Food Science Packaging – Craig R. Hof, Roy A. Ulin, PY MAH Corp, 3M Co

Abstract for “Temperature indicating compositions in matter”

A solvent (I) is a single substance or a mixture of substances that can be adapted to change from a solid at substantially a predetermined temperatures to a liquid. A solvent (I) is a substance that can be either a single or mixed substance and which is able to change from a solid to a liquid phase at substantially the same temperature as it was when it was formed. An indicator system (II), which is composed of one or more substances other than (I), is described in that the solvent (II), when it is present in a liquid state, can change from a solid state at substantially a predetermined temperature to dissolved in the liquid.

Background for “Temperature indicating compositions in matter”

“1. “1.

“The invention relates to the field of temperature-indicating compositions and devices therefor, and in particular, the sub-fields of disposable thermometers and compositions of matter which change characteristics with change in phases for use in disposable thermometers.”

“2. “2.

“For many years the conventional mercury thermometer has been the primary temperature-indicating device which has been used in clinical applications for the measurement of temperature in the human body and other animal bodies, and for the measurement of temperature of gases, liquids, and even solids in commercial and industrial applications. As the observer will quickly see, there are many disadvantages to this type of thermometer due to the poisonous nature of mercury and the construction of the mercury thermometer using fragile glass. For clinical applications that involve humans or other animals, it takes several minutes to get a meaningful temperature reading. Because of its high cost, it is imperative that the mercury thermometer be cleaned after use. Sterilization and sterilization can be costly, both in hospitals, doctors’ offices, at home, or out in the field. In hospital sterilization, there is always the possibility of human error. This can lead to contagious diseases like hepatitis. The mercury thermometer’s fragile nature is a danger, especially when used in children’s hands. Fifth, industrial applications that require the determination of high temperatures in vessels in plants or refineries are more difficult than usual. Because of the extreme temperature difference between the mercury thermometer and the ambient temperature outside, conventional thermometers often have extreme error rates after the withdrawal.

“Accordingly, people have tried for many years to create an inexpensive device from mixtures or materials of any type that would change in some characteristic visible by the naked eye at substantially what temperature is being measured. This was to avoid the inconveniences associated with the mercury thermometer. For instance, Ramsden in British Pat. No. No. Ramsden wanted a substance (see pages 9-223) that would change color at a predetermined temperature. However, he did not specify any. He only mentioned several substances, mainly fatty acids, that would change their opacity, or change from opaque to transparent when phases change from liquid to solid or vice versa (see pages 3-11-18). This would require that indicators layers, dyes, and the like be used in the device.

Finklestein, U.S. Pat. No. 3,521,489 (1970). This type of thermometer uses a flow of melted material through a “holding compartment” and into a “flow-inducing receiver element” (see Column 1, lines 60-72 of ‘489). Temperature indication was achieved, as in the Geldmacher patent. However, this was accomplished by using many different thermally responsive chemical substances, each of which undergoes a complete state change at a predetermined temperature, with corresponding changes from opaque to transparent. Once again, it was evident that any “classical” material would need to be used to change from opaque to transparent at phase change. An indicator dye or material would be needed at the bottom to show the observer the changes in the state of the matter. This would indicate the temperature to be determined. Also see Crites U.S. Patent. No. No. 3,580,079 (1971), which required that the transparent temperature responsive material have the same index for refraction as a roughened glass in order to optically smoothen the window.

“As the search for a disposable mercury thermometer continued, Weinstein and Sagi published U.S. Pat. No. 3,631,720 disclosed a specific device employing a carrier sheet (11 in ‘720) with a plurality of individual temperature-indicating elements distributed over at least one surface of the carrier sheet in the form of a grid with the elements buried in a corresponding number of cavities (located between the sheet 11 and surfaces 20A and 10A), each element 12 having an opaque layer covering an indicator element 20. The indicator material 20 would become visible to the observer after melting the coatings 22 of ‘720. The problem with ‘720 was the fact that a manufacturer of multilayered devices, as shown in FIG. 4 of ‘720 with a \”sandwich\” indicator means 20 in temperature-indicating elements 12 became expensive.”

“In U.S. Pat. No. 3,946,612 (1976) to Sagi and Weinstein, the specification disclosed the use of a heat conducting carrier having a plurality of spaced cavities with a corresponding plurality of solid solutions each comprising an organic layer of at least two different organic chemicals (ortho-chloronitrobromobenzene and ortho-bromonitrobromobenzene) in varied composition ratios deposited in said cavities that would turn from opaque to clear upon a change in phase from solid to liquid. The organic layer (9 in’612) served as a sandwich between an indicator layer (13in’612) and a masking layer or opaque (15 in a multilayered device like U.S. Pat. No. 3,665,770). The cavity in FIG. FIG. 2 of ‘612 was heated at a predetermined temperature. The composition of matter would change to a liquid, permeating indicator 13, and forcing a dye to penetrate the opaque layer to change its color to that of the dye. The construction of the multilayered device ‘612 was fraught with problems. First, it was difficult to make a device that had three layers inside the cavity and two transparent layers outside. The organic composition could not always change completely from liquid to solid. This meant that the nucleation sites in the organic layer 9 remained. Resolidification occurred quickly upon withdrawal of the thermometer. Also, not all dye was forced into either the opaque or upper layer 15. Because of the thickness of the layers it was sometimes difficult to see the color change when only a small amount of dye was transferred into an opague layer. Keele, U.S. Pat., provides other examples of opaque thermometers. No. No. No. No. No. No. No. 3,785,336 (methyl sterate); Godsey, Jr., U.S. Pat. No. No. No. No. No. 3,597,976; Lang, U.S. Pat. No. No. No. 3,704,985 (ortho-chloronitrobenzene:ortho-bromonitrobenzene heat-sensitive material, but no \”space layer\”); Chadha, U.S. Pat. No. 3,712,141 (\”space layer\”); Pickett, U.S. Pat. No. No. No. No. No. 3,826,141; Ayres, U.S. Pat. No. No. No. 3,929,021; Chadha, U.S. Pat. No. 3,956,153; Sagi, U.S. Pat. No. 3,835,990, Keele, U.S. Pat. No. 3,859,856; Sagi et al., U.S. Pat. No. De. 238,661 (1976); Nollen, U.S. Pat. No. 3,895,523; Chilton, U.S. Pat. No. No. No. 3,871,232.”

Chadha, U.S. Pat. explains the phenomenon of undercooling that occurs when heat-responsive materials pass from liquid to solid. No. No.

“Another type of device in another art, and not to be misunderstood with the ‘pure’ thermometer (which is only used for measuring temperature), is the (time-temperature) thermometer or the ?time-temperature? watch that indicates by integrating time and temperature a property (such as the degradation of meat due to high temperatures). Chapman, U.S. Pat. No. No. 2,195,395 describes how to measure the thermal abuse of frozen foods by using a dye in water to determine the pH change. Larsson, U.S. Patent. This was a major breakthrough in this art. No. No. 3,946,611, in which paraformaldehyde 19 is FIG. 2, wherein paraformaldehyde 19 in FIG. The pH of wick 18 is reduced by HCl over time, so the dye and wick become darker (see example 3). A color change is not a sign that the solvent’s phases have changed. Gessler U.S. Patent. No. No. No. No. No. No.

Pickett et al. U.S. Pat. reveals a state-of-the-art method to deposit precisely measured quantities of liquid on a small surface. No. 3,810,779.”

“Japanese Patent Applications Nos. 47-105555 and 50-1055555 respectively show compositions (1) consisting of a dye and an acids with a polymeric material and (2) a color changing dye, an acidic compound and a solvent that change colors but not at the melting point.

“While there have been some abbreviated efforts to find substances that change color when phases change, none of these have been able overcome the problems of using many unrelated compounds and accidental overheating. Jennings, U.S. Pat. No. 2,261,473 is a combination of certain cognizable organic dyes (page 2 column 2, lines 13-28), and certain solvents (2 page 2, column 1, lines 56-60). The pH change changes the color of these dyes but Kluth needs 45 to 50 different compositions within a range similar to the human clinical range. Renbaum, U.S. Patent. This is a major advancement in the art. No. No. 3.700,603 in which no solvent system was employed but where the organic moieties (“electron donors” and “electron receivers”) change color when phases change (see Table I columns 5 and 6). Renbaum did not appear to seek out a solvent system to match his electron donor-acceptor pair. This would have meant that a variety of parts would be required to determine almost any temperature range, such as Kluth’s problems. Also see Hammond, U.S. Pat. No. No. 3,576,604, who does not use solvents at a variety of temperatures.”

A disposable thermometer that was inexpensive was sought after by the thermometer industry. It would have been easy to construct and would use materials that would change some characteristics but not easily reversible upon withdrawal from the source. It would be possible to provide chemical substances that change color upon changing phases. This would eliminate the need for dyes in indicator layer. A disposable thermometer was also needed to magnify the presence an indicator layer in cases that involved “classical” substances, which changed only from opaque or transparent when changing from liquid to solid phase.

“MISCELLANEOUS”

A short, unpublished memorandom from June 1975 was written by a scientist who was not affiliated with the inventors of disposable thermometry. He was trying to create a reversible thermometer by changing the color of a dye using molten thermometer chemical instead of solid thermometer chemical. This led to a fascinating phenomenom. He discovered that melting and freezing caused a very obvious color change by mixing bromothymol and ethyl blue together in a “thermometer chemical”. The color became yellow-orange when the chemical solidified. He found that the reaction was completely reversible. Bromophenol blue and purple were apparently substituted for bromothymol. The scientist tested the compounds with various dyes and indicators. Similar structures that did not contain bromine atoms failed to work, such as thymol blue and cresol phthalein. Para rosaniline base, para-rosaniline acetate and crystal violet were all suitable structures to replace ethyl. Although not an indicator or dye, 8-hydroxyquinoline was used as a substitute. It allowed the bromo compound’s color to change from yellow-green to blue-green, from liquid to solid form. The scientist stated that the color change occurred only in aromatic systems like thymol, 2-ethoxybenzamide and 2-naphthyl. Color changes were not observed in aliphatic compounds like 2-chloroacetamide or sorbitol. The report concluded that imidazole was not too basic to show any color changes since the indicators returned to their basic state and stayed there.”

“An intercompany sales of thermometers with Pinacyanol Iodide/OCNB/OBNB within claim 1 was made Sept. 30, 1977 for research purposes by an unincorporated division, assignee, of Applicants to Organon Technika B.V., a similar company to said assignee. The public was first made aware of the assignment by the assignee in the United States shortly after January 1, 1978.

“AN INVENTION”

The present inventors discovered about this failed attempt around 18 months after the date of the memorandum. They did so through a technology transfer agreement, among other attempts using different methods (uses of metal complexes, different solutions to cations, etc.). To obtain a disposable and possibly reversible thermometer at a low price, we performed identical experiments to the memorandum. These experiments did not produce the desired color change for disposable thermometers. This was due to (1) the high melting point experienced, and (2) the memorandum didn’t specify how the components were to mixed. Therefore, much experimentation was required to adjust the ratios between the first and second types mentioned above in order for any color change to occur. Even though the inventors had determined the right ratios between ‘Group I”, ‘Group II”, and “Group III” types of materials, the large melting range remained a problem. The above unpublished memo did not mention any of the phenomena of the ‘Group III” compounds.

“Surprisingly, when the Group I and Group II components were mixed in a certain ratio found by the inventors and were added to the composition (at a total weight of about 0.05%), and when the solvent (ortho-chloronitrobenzene and ortho-bromonitrobenzene) was employed in a composition almost entirely free of nucleating agents (impurities, especially less than 0.1 weight percent), a sharp and narrow melting range (or \”point\”) with a sharp color change was discovered for the composition, which at the same time exhibited the desired color change with change in phases and a remarkable color stability in the liquid upon heating, presumably due to some type of undercooling effect, i.e., upon withdrawal from the source of the temperature to be measured, the materials were not readily susceptible to refreezing and color reversibility. It is not known what caused this sudden color change phenomenon. Only theories have been offered.

“THE PRESENT AART”

“German Patent Application No. 27,15,752 (published Oct. 27, 1977) discloses, inter alia, the use of an ionic reaction between the solvent mixture (for example, n-octadecane/n-eicosane) upon melting to ionize a pair of color producing reagents (for example methyl red and acid clay). The color signal found in No. The color signal in No. 27,15,752 was created by physically seperating two reactive components. They are then joined at a visible site by the action and flow of the temperature sensitive liquid. This can be achieved by either applying each reagent to separate sides of a bibulum, or by dissolving each reagent into the melting substance, and then applying each reagent to the bibulum. U.S. Pat. is more relevant than the German reference. No. 3,712,141 (Chadha).”

“Suzuki et al. U.S. Pat. No. No.

“An application filed on or around Apr. 13, 1978, Ser. No. 896,116, entitled \”DYE IN CHEMICAL TEMPERATURE INDICATING DEVICE\”, and assigned to assignee of the present invention, describes an invention wherein a cavity is filled with a solid mixture (preferably ortho-chloronitrobenzene/orthobromonitrobenzene (hereinafter OCNB/OBNB), including a dye which, although not changing color with change in phase, upon melting turns the color of a bibulum layer to the color of the dye.”

These novel and stable temperature-indicating compositions can be used in many types of disposable thermometers to measure the temperature of humans and other animals, as well as other temperature measurement applications in industries. These novel chemical compositions can also be used in industrial or clinical applications that are induced temperature changes. However, they may also be extended to other indications or measuring systems in the event of a color change. This could be used to indicate a liquid-to-solid or liquid to liquid phase change in non-polar solvents or weaklypolar solvents induced pressure, radiation or other kinetic energies.

“The components of the novel compositions consist of:

“(1) A solvent (I) is a substance consisting of one or more substances that can be adapted to change from a stable state at substantially a temperature predetermined to a liquid state.

“(2) An indicator system (II) containing one or more substances that are different from (I), and characterized in the following:

“(a), (II), is soluble in (I), when the latter is liquid phase.

“(b) (II), changes a color visible by the naked eye when (I), passes from the solid-to-liquid phase or from liquid to solid phase.”

“The constituents of the novel compositions of matter substantially free of impurities most preferably comprise (a) a suitable inert solvent (i.e., stable and in which Group I-III moieties are soluble, and generally aromatic hydrocarbons) adapted to change from a solid state at substantially a predetermined temperature to a liquid state, and (b) an effective amount (generally about 0.005 to about 0.5 percent preferably about 0.025 to about 0.05 percent by weight) of (1) one or more Group III compounds (pinacyanol iodide, quinaldine red, 1,1′-diethyl-2,2′-cyanine iodide, pinacyanol chloride, thionin, methylene blue, cresol red, chlorophenol red, neutral red iodide, neutral red chloride, crystal violet, acridin orange, toluidin blue O, Orasol Orange RLN?, Orasol Navy Blue?, Irgalith Red PR?, Fat Red BS?, Xylene Cyanol FF?, Rhodamine 6G?, Irgalith Magenta TCB?, Irgalith Pink TYNC?, Toluidin blue O?, Savinyl Green B?, Savinyl Blue RS?, purpurin, 3,3′-diethylthiadicarbocyanine iodide, cryptocyanine, Dicyanine A?, Merocyanine 540?, 4-(P-ethoxyphenylazo)-m-phenylene diamine monohydrochloride, Yellow Orange S?, Chrysoidin G?, fuchsin, aurintricarboxylic acid (ammonium salt), Victoria Blue R?, Pyronin G?, gallein Erythrosin Yellowish Blend?, chlorophenol blue, bromophenol blue, bromocresol purple, Coriphosphine O?, acriflavine, acridine orange, rhoduline violet, Alizarin cyanin 2R?, Alizarin Red S?, alcannin, Aurantia?, Direct Green G?, Fast Red Salt 3GL?, Fast Blue Salt BB?, Fast Garnet Salt GBC?, Carta Yellow G 180 o/o, Muroxide Savinyl Blue GLS?, Irgalith Blue GLSM?, phthalocyaline, Di Amingreen B?, Alizarin Blue S?, Celliton Blue Extra?, Janus Green, dimethyl yellow, Fast Yellow, Methyl red sodium salt, Alizarin yellow R?, Eriochrome black T?, Chromotrope 2R?, Ponceau 6R?, Brilliant Ponceau G/R/2R?, chromolan yellow, Sudan Red B?, Bismarck brown G?, Fat Black?, Resorcin Brown?, Benzofast pink 2BL?, Oil Red EGN?, Euroglaucine, Fuchsin NB?, parafuchsin, Patent Blue?, Irgalith Blue TNC?, Phloxin B?, fluorescein sodium salt, Rhodamine B base?, Eosinscarlet, Eosin Yellowish?, Erythrosin extrabluish, 4,5-dibromo fluorescein, ethyleosin, Phloxine, Cyanovin B?, chlorocresol green, pinacyanol bromide, 2-(p-dimethylaminostyryl)-1-1-ethyl pyridinium iodide, ethyl red, nigrosine, savinyl blue B?, Orasol Blue BLN?, Safranin O?, Azocarnun G?, Phenosafranine, Azocarmine BX?, Solophenyl Brilliant Blue BL?, Nile Blue A?, gallocyanine, gallanine blue, celestine blue, methylene green, Azure A/B/C?, Blue VIF Organol?, Alizarin, Nitrofast Green GSB?, quinalizarine, Oil Blue N?, Solvay purple, Ciba Blue?, Indigo synthetic?, Chromophtal Bordeaux RS?, acid Alizarin Red B?, 5-Aminoflourescein, Rose Bengal?, Martius Yellow?, Chicago Blue 6B?, Alcian Blue 8GX, cresyl violet, 4,4’Bis(dimethylamino)benzylhdrol, Zinc Pthalocyanine, Sudan III?, Pyronin Y?, Toluylene Blue?, Cresyl Violet perchlorate, Mendola’s Blue?, 3,3′-diethylthiadicarbocyanine iodide, Phosphine Dye?, Nitron?, Cresyl violet acetate, Ceres Orange R?, 4-phenylazo-1-naphthyl-amine, 4-(4-Dimethylamino-1-naphthylazo- 3-methoxybenzene sulfonic acid, Bindschedler’s Green?, and p-(p-dimethylamino phenylazo) benzoic acid and neocyanine) or in the alternative, (2) a similarly small amount of one or more of a Group I body of compounds consisting of the halogenated sulfonphthaleins and organic acids having a pK of less than about four, together with one or more of a Group II body of compounds consisting of the aminotriphenylmethanes and their soluble salts, 8-hydroxyquinoline, and the cyanines (with the proviso that if the Group II compounds consist solely of one or more aminotriphenylmethanes or their soluble salts, then Group I must be selected from one or more of the group consisting of oxalic acid, suitable soluble sulfonic acids, the tetrahalogenated sulfonphthaleins and the other known soluble organic acids having a pK1 of about 2 or less dissolved in the above-mentioned suitable solvents. Examples of Group I compounds suitable for use in this invention are one or more of the group consisting of oxalic acid, maleic acid, dichloroacetic acid, trichloroacetic acid, naphthalene sulfonic acid, benzensulfonic acid, chloroanilic acid, bromophenol blue, bromothymol blue, chlorophenol red, bromochlorophenol blue, bromocresol green, 3,4,5,6-tetrabromophenolsulfonphthalein, bromophenol red, chlorophenol blue, bromocresol purple, 2,4-dinitrobenzenesulphonic acid, and chlorocresol green. Examples of Group II compounds suitable for use in this invention are ethyl red, crystal violet, pararosaniline, pararosaniline acetate, basic fuchsin, 8-hydroxyquinoline, ethyl violet, brilliant green, pinacyanol chloride, and 3,3′-diethylthiodicarbocyanine. When Group III compounds are unavailable, preferred combinations of Group I compounds and Group II compounds include: (1) bromophenol Blue: basic fuchsin;(2) chlorophenol Blue: ethyl blue; (3) chlorophenol Red: ethyl res; (4) bromophenol Red: ethyl res; (5) bromochlorophenol Bleu: brilliant green. The weight ratio of Group I and Group II compounds should not exceed or equal to 3 to 1. In an effective amount, a Group III compound may be used either alone or in combination with a small amount (preferably less that 0.5 percent) from Group I or Group II compounds.

“The invention also contemplates a novel temperature-indicating device comprising (a) a flat or gradually curved heat-conducting carrier having one or more regions defined therein, preferably cavities, to determine a like number of predetermined temperatures at temperatures separated by a constant increment in a predetermined temperature range by means of a like number of different thermally-responsive compositions of matter, each cavity associated with one of the predetermined temperatures and each substantially without impurities, (b) if the novel compositions of our invention are not employed, an indicator means located at the bottom of each said cavities, (c) a transparent means in sealing engagement with a carrier means above each cavity and overlying each of said cavities to form an enclosure for each cavity between the walls of the cavity and the transparent means, and (d) one of said compositions of matter adapted to change from a solid to a liquid at substantially the predetermined temperature associated with said cavity, and in addition, substantially filling the cavity except for a substantially spherical void within said cavity and composition of matter. The novel temperature indicator device does not contemplate the necessity of employing the novel temperature-indicating compositions of matter, but can, in the alternative, employ the \”classical\” compositions of matter (compositions other than our novel compositions which generally change from opaque to transparent with a corresponding change in phase at a predetermined temperature). On the other hand, if the novel compositions of matter are employed, the indicator means in the novel temperature-indicating device may be eliminated. The invention allows for the use of the new device to replace ordinary opaque thermometers. This is possible when the backing material is colored or when bibulum paper is used as a cover or numerals are placed at the bottom of void spaces.

“In one aspect, this invention contemplates providing thermally-sensitive compositions which undergo a change of state, i.e., from solid to liquid, at precisely predetermined temperatures with a corresponding change of color visible to the naked eye; such temperature-sensitive compositions being solid solutions of certain organic compounds to be hereinafter described.”

“Another aspect is the invention’s use of an indicating device associated with novel compositions, so that it can quickly indicate the change in state of such matter and, therefore, the temperature of the subject.”

“Furthermore,” another aspect of the invention is directed at the provision of novel compositions or matter that may be applied to any other indication or measurement system other than temperature. The color change described in our invention can be used to indicate a fluid-to-solid, liquid-toliquid, or weakly-polar solvent induced either by pressure, radiation or other kinetic energy sources.

“In yet another aspect, the invention is directed toward the provision of a novel temperature-indicating device suitable as a disposable thermometer, in which each temperature-sensitive composition of matter used is substantially free of impurities so that said composition of matter upon complete melting has few nucleation sites and is not conducive to resolidification, i.e., the temperature-sensitive composition of matter has the property of stable undercooling and will remain liquid for at least several minutes up to several hours when subjected to a surrounding temperature that is somewhat below the freezing point of the composition.”

“And yet still another aspect, the present invention is directed toward the provision of a novel temperature-indicating device (comprising a flat or gradually curved heat conducting carrier means with one or more cavities therein and a transparent means in sealing engagement with said carrier means above the cavity) for use of so-called \”classical\” temperature-sensitive materials, e.g., compositions of matter commonly employed in disposable thermometers which change from opaque to become transparent upon a change in phase from solid to liquid, through the use of a substantially spherical void within said cavity containing the composition of matter determining the temperature to be indicated to magnify the presence of an indicator layer at the bottom of said cavity.”

“Finally and while some aspects of our invention will be apparent from the detailed description thereof infra,” says the inventor, “The overall object of our invention to provide generally useful improvements on change-of-state thermometers.”

“The details of the invention pertaining to the novel temperature-indicating device will become more evident from the detailed description to follow with reference to the appended drawings:”

“FIG. 2 is a partial plan view from the horizontal of a flat or gradually curved novel heat-conducting carrier having a cavity defined therein, which cavity forms an enclosure for a temperature-sensitive \”classical\” composition of matter therein when such cavity is covered by a transparent cover sheet means in sealing engagement with the carrier means overlying the heat-conducting carrier means and above the cavity; the figure also depicts a substantially spherical cavity inside the temperature-sensitive composition of matter;”

“FIG. 3. is a vertical section taken at line 3–3 in FIG. It is the partial plan view taken from above the cavity in FIG. 2. 2. When a painted material is located at the bottom of said cavity as an indicator means:

“FIG. 4. is a vertical section taken at line 4–4 in FIG. It is a partial view from the overhead cavity of FIG. 2. 2. When a painting material is magnified by a spherical cavity of the “classical” composition, after it has melted;

“FIG. “FIG.

“FIG. “FIG.

“FIG. 8 is a plan view of a temperature-indicating device from the horizontal (together with a plan view from the vertical of a label on said device) using the novel compositions of matter of this invention for indication of a temperature exceeding a predetermined safe limit. We will discuss the details in detail below.

“FIG. 9 is a three-dimensional cutaway view taken from a skewed angle on a thermometer. It contains a heat conductor means with a grid filled with cavities, and enclosed in a case where only the handle of that heat-conducting means protrudes.

“FIG. 11. is a partial horizontal plan view taken along line II-II of FIG. 10 reveals several cavities in the heat conductor carrier means. Each cavity is surrounded by transparent cover sheets and bottom transparent bottom plates.

“FIG. 12 is a plan view of a flat temperature-indicating device from the vertical without the use of a case, comprising a heat-conducting carrier means with a grid of cavities thereon; and”

“FIG. “FIG. 12 shows the heat-conducting carrier, cavities inside, transparent cover sheet, and a bottomplate.”

“FIG. 14 is a plan taken from the vertical view of a transparent support member to a disposable clinical thermometer. 10, or FIGS. 12-13.”

“FIG. FIG. 15 shows a plan view from the vertical end of the transparent support member. 14 except for sealing engagement, using a disposable thermometer like that shown in FIG. 10, with a Fahrenheit scale ranging from 96.0 to 104.8 degrees Fahrenheit, graduated in increments of 0.2 degrees Fahrenheit.

“FIG. 16. This is a plan view from the vertical end of FIG. 14 except for sealing engagement with the disposable thermometer shown in FIG. 10 with a Centigrade scale ranging from 35.5 to 40.4 degrees Centigrade, graduated in 0.1 degree Centigrade increments.

“FIG. “FIG.

“FIG. FIG. 18 shows a partial view of the horizontal as FIG. 17 with an additional layer of PIB at the lower edges of each cavity.

“Throughout the Detailed Description below, the terms \”novel thermally-responsive substance\”, \”novel thermally-responsive material\”, \”novel temperature-indicating compositions of matter\”, \”novel temperature-sensitive solid solutions\”, \”novel temperature-indicating solid solutions\”, and \”novel solid solutions\”, or variations thereof, are used interchangeably to denote the same novel materials of our invention. The terms “compositions or classic compositions of material” and ‘classical compositions or matter” can be used interchangeably to refer to compounds that change from opaque to transparent, with corresponding changes from the liquid to solid state or vice versa.

“1. “1.

It was discovered that certain organic compounds, to be described later, can form novel solid solutions. These solutions undergo a change of state from liquid to solid at predetermined temperatures, with corresponding changes in color visible by the naked eye. Solid solutions are well-known and refer to a homogenous mixture of two or more solids. The present invention contemplates novel solid solutions that are made up of multiple organic compounds, preferably three to four. They contain varying amounts of at least two of the compounds that form a solvent. Each novel solid solution experiences a rapid change in state at a predetermined temperature, or substantially thereabouts. A “change in color visible by the naked eye” refers to a change in wavelength of the luminous light from a source. This is visible to anyone with normal vision and eyesight if the intensity of the luminous flash surrounding the source is greater than or equal to 5 lumens per square feet (ft-c). This change in wavelength of luminous flux visible to the naked eye will most likely be less than 175 Angstroms and more preferably 500 Angstroms.

“It is important to emphasize that once a proposed solvent system (consisting one or more compounds), has been chosen, the compound(s), of the system, must be tested for Group I-III moiety stability (i.e. inertness and soluble in the compound(s). Routine testing is required, according to the expertise of those skilled in the art. This solvent system can only be used if the compound(s) of the solvent system dissolve the Group I-III moieties, and are inert towards them.

“While it is possible for a solvent system to contain only one compound in rare circumstances, most times (as those skilled with the art will understand) the temperature that must be determined cannot be easily obtained without mixing several organic compounds for its solvent system. Hence, for a temperature-indicating device, two or more related organic compound constituents in the solvent are especially helpful for measuring forty or more temperatures located at regular increments.”

It is evident from the above description that the selection and use of inert solvents towards organic moieties in novel composition of matter must be carefully considered. Not all organic compounds can be used for this purpose, and some may not be within the desired temperature range. Any solvent that is inert towards organic moieties, and in which organic moieties can be soluble in the liquid phase of the solvent is a suitable solvent. Simple alcohols and organic substances are sometimes more suitable than aromatic compounds. The organic compounds which are particularly adapted for the formations of solid solutions which can serve a novel temperature-indicating composition in accordance with the present invention are generally those which are aromatic weakly polar (e.g., compounds which are immiscible in water and have a dielectric constant less than about 35) or moderately polar aromatic organic compounds, as well as the requirements of organic moiety solublity and inertness towards the organic moieties. It has been found that the weakly polar and moderately polar aromatic compounds have an analogous chemical structure (e.g. homologs, analogs and optical isomers). These are used to prepare novel solid solutions for the purposes of the invention. It is also preferable for solvent solutions to have a linear, or substantially linear, temperature composition liquidous curve, especially over the desired temperature range, such as the human clinical temperature range. Exemplary weakly polar or nonpolar aromatic solvents are ortho-chloronitrobenzene, ortho-bromonitrobenzene, naphthalene, 2-ethoxybenzamide, 1-thymol, 2-naphthol, ortho-iodonitrobenzene, meta-iodonitrobenzene, para-iodonitrobenzene, para-chloronitrobenzene, meta-bromonitrobenzene, para-dibiomonitrobenzene and para-toluic acid. It is important to remember that not all solvents are suitable for all organic moieties. Also, not every solvent will work for every temperature. For a temperature to be measured, it is recommended to start investigating for the right temperature. Then select a suitable solvent system from the following compounds:

“(1) Moderately or weakly Polar Aromatic Compounds, i.e. compounds with a dielectric constant less than 35;”

“(2) water; or”

“(3) aromatic or aliphatic compounds other that (1)-(2), which are relevant to the temperatures to determine, and which are ‘inert to the Group I to III dyes.”

“The components of the novel compositions consist of:

“(1) A solvent (I) is a substance consisting of one or more substances that can be adapted to change from a stable state at substantially a temperature predetermined to a liquid state.

“(2) An indicator system (II) containing one or more substances that are different from (I), and characterized in that”

“(a), (II), is soluble in (I), when the latter is liquid phase.

“(b) (II), changes color visible to naked eye when (I), passes from the solid to liquid phase or from liquid to solid phase.”

“It is within the reach of skilled art practitioners to find a suitable solvent for a temperature range to be measured and for desired color change (choosing among the various Group I-III substances) to do so. This means that the solvent must be in towards the Group I-III compound and soluble in the liquid phase of said solvent.

“The solid solutions made from ortho-chloronitrobenzene and ortho-bromonitrobenzene have been found to be most preferable for use in temperature measurements in the clinical range within the aforesaid accuracy. As those who are skilled in the art will understand, any combination of aromatic solvents in which the organic moieties described above are soluble and stable may be used for thermometers. If they can be combined to form a homogenous solution, it is possible.

“Preferably, the novel composition of matter consists essentially:

“(A) A suitable solvent that is capable of changing from a solid at a predetermined temperature into a liquid, and

“(B). An effective amount of one of the suitable organic moieties, soluble in said solvent and adapted for changing the color of composition visible to naked eye upon change in state of solvent at substantially the predetermined temperatures.

“(1) A group III body of single compounds, consisting of the monoazo, diazo and triarylmethane classes of dyes, suitable colors from the following classes; azine and oxazine?, anthraquinone?, sulphonephthalein?, acridul?, azine?, thiazine?, anthraquinone?, indigold?, Cara Yellow G 180 o/o, Murexide, Irgalithblue GLSM?

“(2) combinations of:

“(a) One or more organic acids compounds, with a pK less than four and

“(3) combinations of”

“(a) One or more organic acids with a pK less than 2 and

“(b) one of more acid dyes, or acid indicators”

“(4) Mixtures of”

“(a) One or more organic acids compounds with a pK less than approximately 4”

“and”

“(b) one of the group I bodies of compounds”

“(5) combinations of”

“(a) One or more basic indicators or dyes and

“(b) one of the group I bodies of compounds”

“(6) combinations of”

“(a) One or more dyes containing a molecular structure that contains a lactone group.

“(b) One or more acids with a pK between 8 and 12.”

“The compounds listed in group III are classified according the Colour Index, 3rd edition (1971), published at the Society of Dyers and Colourists of Great Britain and Conn?s Biological Stains (9th ed 1977).

Summary for “Temperature indicating compositions in matter”

“1. “1.

“The invention relates to the field of temperature-indicating compositions and devices therefor, and in particular, the sub-fields of disposable thermometers and compositions of matter which change characteristics with change in phases for use in disposable thermometers.”

“2. “2.

“For many years the conventional mercury thermometer has been the primary temperature-indicating device which has been used in clinical applications for the measurement of temperature in the human body and other animal bodies, and for the measurement of temperature of gases, liquids, and even solids in commercial and industrial applications. As the observer will quickly see, there are many disadvantages to this type of thermometer due to the poisonous nature of mercury and the construction of the mercury thermometer using fragile glass. For clinical applications that involve humans or other animals, it takes several minutes to get a meaningful temperature reading. Because of its high cost, it is imperative that the mercury thermometer be cleaned after use. Sterilization and sterilization can be costly, both in hospitals, doctors’ offices, at home, or out in the field. In hospital sterilization, there is always the possibility of human error. This can lead to contagious diseases like hepatitis. The mercury thermometer’s fragile nature is a danger, especially when used in children’s hands. Fifth, industrial applications that require the determination of high temperatures in vessels in plants or refineries are more difficult than usual. Because of the extreme temperature difference between the mercury thermometer and the ambient temperature outside, conventional thermometers often have extreme error rates after the withdrawal.

“Accordingly, people have tried for many years to create an inexpensive device from mixtures or materials of any type that would change in some characteristic visible by the naked eye at substantially what temperature is being measured. This was to avoid the inconveniences associated with the mercury thermometer. For instance, Ramsden in British Pat. No. No. Ramsden wanted a substance (see pages 9-223) that would change color at a predetermined temperature. However, he did not specify any. He only mentioned several substances, mainly fatty acids, that would change their opacity, or change from opaque to transparent when phases change from liquid to solid or vice versa (see pages 3-11-18). This would require that indicators layers, dyes, and the like be used in the device.

Finklestein, U.S. Pat. No. 3,521,489 (1970). This type of thermometer uses a flow of melted material through a “holding compartment” and into a “flow-inducing receiver element” (see Column 1, lines 60-72 of ‘489). Temperature indication was achieved, as in the Geldmacher patent. However, this was accomplished by using many different thermally responsive chemical substances, each of which undergoes a complete state change at a predetermined temperature, with corresponding changes from opaque to transparent. Once again, it was evident that any “classical” material would need to be used to change from opaque to transparent at phase change. An indicator dye or material would be needed at the bottom to show the observer the changes in the state of the matter. This would indicate the temperature to be determined. Also see Crites U.S. Patent. No. No. 3,580,079 (1971), which required that the transparent temperature responsive material have the same index for refraction as a roughened glass in order to optically smoothen the window.

“As the search for a disposable mercury thermometer continued, Weinstein and Sagi published U.S. Pat. No. 3,631,720 disclosed a specific device employing a carrier sheet (11 in ‘720) with a plurality of individual temperature-indicating elements distributed over at least one surface of the carrier sheet in the form of a grid with the elements buried in a corresponding number of cavities (located between the sheet 11 and surfaces 20A and 10A), each element 12 having an opaque layer covering an indicator element 20. The indicator material 20 would become visible to the observer after melting the coatings 22 of ‘720. The problem with ‘720 was the fact that a manufacturer of multilayered devices, as shown in FIG. 4 of ‘720 with a \”sandwich\” indicator means 20 in temperature-indicating elements 12 became expensive.”

“In U.S. Pat. No. 3,946,612 (1976) to Sagi and Weinstein, the specification disclosed the use of a heat conducting carrier having a plurality of spaced cavities with a corresponding plurality of solid solutions each comprising an organic layer of at least two different organic chemicals (ortho-chloronitrobromobenzene and ortho-bromonitrobromobenzene) in varied composition ratios deposited in said cavities that would turn from opaque to clear upon a change in phase from solid to liquid. The organic layer (9 in’612) served as a sandwich between an indicator layer (13in’612) and a masking layer or opaque (15 in a multilayered device like U.S. Pat. No. 3,665,770). The cavity in FIG. FIG. 2 of ‘612 was heated at a predetermined temperature. The composition of matter would change to a liquid, permeating indicator 13, and forcing a dye to penetrate the opaque layer to change its color to that of the dye. The construction of the multilayered device ‘612 was fraught with problems. First, it was difficult to make a device that had three layers inside the cavity and two transparent layers outside. The organic composition could not always change completely from liquid to solid. This meant that the nucleation sites in the organic layer 9 remained. Resolidification occurred quickly upon withdrawal of the thermometer. Also, not all dye was forced into either the opaque or upper layer 15. Because of the thickness of the layers it was sometimes difficult to see the color change when only a small amount of dye was transferred into an opague layer. Keele, U.S. Pat., provides other examples of opaque thermometers. No. No. No. No. No. No. No. 3,785,336 (methyl sterate); Godsey, Jr., U.S. Pat. No. No. No. No. No. 3,597,976; Lang, U.S. Pat. No. No. No. 3,704,985 (ortho-chloronitrobenzene:ortho-bromonitrobenzene heat-sensitive material, but no \”space layer\”); Chadha, U.S. Pat. No. 3,712,141 (\”space layer\”); Pickett, U.S. Pat. No. No. No. No. No. 3,826,141; Ayres, U.S. Pat. No. No. No. 3,929,021; Chadha, U.S. Pat. No. 3,956,153; Sagi, U.S. Pat. No. 3,835,990, Keele, U.S. Pat. No. 3,859,856; Sagi et al., U.S. Pat. No. De. 238,661 (1976); Nollen, U.S. Pat. No. 3,895,523; Chilton, U.S. Pat. No. No. No. 3,871,232.”

Chadha, U.S. Pat. explains the phenomenon of undercooling that occurs when heat-responsive materials pass from liquid to solid. No. No.

“Another type of device in another art, and not to be misunderstood with the ‘pure’ thermometer (which is only used for measuring temperature), is the (time-temperature) thermometer or the ?time-temperature? watch that indicates by integrating time and temperature a property (such as the degradation of meat due to high temperatures). Chapman, U.S. Pat. No. No. 2,195,395 describes how to measure the thermal abuse of frozen foods by using a dye in water to determine the pH change. Larsson, U.S. Patent. This was a major breakthrough in this art. No. No. 3,946,611, in which paraformaldehyde 19 is FIG. 2, wherein paraformaldehyde 19 in FIG. The pH of wick 18 is reduced by HCl over time, so the dye and wick become darker (see example 3). A color change is not a sign that the solvent’s phases have changed. Gessler U.S. Patent. No. No. No. No. No. No.

Pickett et al. U.S. Pat. reveals a state-of-the-art method to deposit precisely measured quantities of liquid on a small surface. No. 3,810,779.”

“Japanese Patent Applications Nos. 47-105555 and 50-1055555 respectively show compositions (1) consisting of a dye and an acids with a polymeric material and (2) a color changing dye, an acidic compound and a solvent that change colors but not at the melting point.

“While there have been some abbreviated efforts to find substances that change color when phases change, none of these have been able overcome the problems of using many unrelated compounds and accidental overheating. Jennings, U.S. Pat. No. 2,261,473 is a combination of certain cognizable organic dyes (page 2 column 2, lines 13-28), and certain solvents (2 page 2, column 1, lines 56-60). The pH change changes the color of these dyes but Kluth needs 45 to 50 different compositions within a range similar to the human clinical range. Renbaum, U.S. Patent. This is a major advancement in the art. No. No. 3.700,603 in which no solvent system was employed but where the organic moieties (“electron donors” and “electron receivers”) change color when phases change (see Table I columns 5 and 6). Renbaum did not appear to seek out a solvent system to match his electron donor-acceptor pair. This would have meant that a variety of parts would be required to determine almost any temperature range, such as Kluth’s problems. Also see Hammond, U.S. Pat. No. No. 3,576,604, who does not use solvents at a variety of temperatures.”

A disposable thermometer that was inexpensive was sought after by the thermometer industry. It would have been easy to construct and would use materials that would change some characteristics but not easily reversible upon withdrawal from the source. It would be possible to provide chemical substances that change color upon changing phases. This would eliminate the need for dyes in indicator layer. A disposable thermometer was also needed to magnify the presence an indicator layer in cases that involved “classical” substances, which changed only from opaque or transparent when changing from liquid to solid phase.

“MISCELLANEOUS”

A short, unpublished memorandom from June 1975 was written by a scientist who was not affiliated with the inventors of disposable thermometry. He was trying to create a reversible thermometer by changing the color of a dye using molten thermometer chemical instead of solid thermometer chemical. This led to a fascinating phenomenom. He discovered that melting and freezing caused a very obvious color change by mixing bromothymol and ethyl blue together in a “thermometer chemical”. The color became yellow-orange when the chemical solidified. He found that the reaction was completely reversible. Bromophenol blue and purple were apparently substituted for bromothymol. The scientist tested the compounds with various dyes and indicators. Similar structures that did not contain bromine atoms failed to work, such as thymol blue and cresol phthalein. Para rosaniline base, para-rosaniline acetate and crystal violet were all suitable structures to replace ethyl. Although not an indicator or dye, 8-hydroxyquinoline was used as a substitute. It allowed the bromo compound’s color to change from yellow-green to blue-green, from liquid to solid form. The scientist stated that the color change occurred only in aromatic systems like thymol, 2-ethoxybenzamide and 2-naphthyl. Color changes were not observed in aliphatic compounds like 2-chloroacetamide or sorbitol. The report concluded that imidazole was not too basic to show any color changes since the indicators returned to their basic state and stayed there.”

“An intercompany sales of thermometers with Pinacyanol Iodide/OCNB/OBNB within claim 1 was made Sept. 30, 1977 for research purposes by an unincorporated division, assignee, of Applicants to Organon Technika B.V., a similar company to said assignee. The public was first made aware of the assignment by the assignee in the United States shortly after January 1, 1978.

“AN INVENTION”

The present inventors discovered about this failed attempt around 18 months after the date of the memorandum. They did so through a technology transfer agreement, among other attempts using different methods (uses of metal complexes, different solutions to cations, etc.). To obtain a disposable and possibly reversible thermometer at a low price, we performed identical experiments to the memorandum. These experiments did not produce the desired color change for disposable thermometers. This was due to (1) the high melting point experienced, and (2) the memorandum didn’t specify how the components were to mixed. Therefore, much experimentation was required to adjust the ratios between the first and second types mentioned above in order for any color change to occur. Even though the inventors had determined the right ratios between ‘Group I”, ‘Group II”, and “Group III” types of materials, the large melting range remained a problem. The above unpublished memo did not mention any of the phenomena of the ‘Group III” compounds.

“Surprisingly, when the Group I and Group II components were mixed in a certain ratio found by the inventors and were added to the composition (at a total weight of about 0.05%), and when the solvent (ortho-chloronitrobenzene and ortho-bromonitrobenzene) was employed in a composition almost entirely free of nucleating agents (impurities, especially less than 0.1 weight percent), a sharp and narrow melting range (or \”point\”) with a sharp color change was discovered for the composition, which at the same time exhibited the desired color change with change in phases and a remarkable color stability in the liquid upon heating, presumably due to some type of undercooling effect, i.e., upon withdrawal from the source of the temperature to be measured, the materials were not readily susceptible to refreezing and color reversibility. It is not known what caused this sudden color change phenomenon. Only theories have been offered.

“THE PRESENT AART”

“German Patent Application No. 27,15,752 (published Oct. 27, 1977) discloses, inter alia, the use of an ionic reaction between the solvent mixture (for example, n-octadecane/n-eicosane) upon melting to ionize a pair of color producing reagents (for example methyl red and acid clay). The color signal found in No. The color signal in No. 27,15,752 was created by physically seperating two reactive components. They are then joined at a visible site by the action and flow of the temperature sensitive liquid. This can be achieved by either applying each reagent to separate sides of a bibulum, or by dissolving each reagent into the melting substance, and then applying each reagent to the bibulum. U.S. Pat. is more relevant than the German reference. No. 3,712,141 (Chadha).”

“Suzuki et al. U.S. Pat. No. No.

“An application filed on or around Apr. 13, 1978, Ser. No. 896,116, entitled \”DYE IN CHEMICAL TEMPERATURE INDICATING DEVICE\”, and assigned to assignee of the present invention, describes an invention wherein a cavity is filled with a solid mixture (preferably ortho-chloronitrobenzene/orthobromonitrobenzene (hereinafter OCNB/OBNB), including a dye which, although not changing color with change in phase, upon melting turns the color of a bibulum layer to the color of the dye.”

These novel and stable temperature-indicating compositions can be used in many types of disposable thermometers to measure the temperature of humans and other animals, as well as other temperature measurement applications in industries. These novel chemical compositions can also be used in industrial or clinical applications that are induced temperature changes. However, they may also be extended to other indications or measuring systems in the event of a color change. This could be used to indicate a liquid-to-solid or liquid to liquid phase change in non-polar solvents or weaklypolar solvents induced pressure, radiation or other kinetic energies.

“The components of the novel compositions consist of:

“(1) A solvent (I) is a substance consisting of one or more substances that can be adapted to change from a stable state at substantially a temperature predetermined to a liquid state.

“(2) An indicator system (II) containing one or more substances that are different from (I), and characterized in the following:

“(a), (II), is soluble in (I), when the latter is liquid phase.

“(b) (II), changes a color visible by the naked eye when (I), passes from the solid-to-liquid phase or from liquid to solid phase.”

“The constituents of the novel compositions of matter substantially free of impurities most preferably comprise (a) a suitable inert solvent (i.e., stable and in which Group I-III moieties are soluble, and generally aromatic hydrocarbons) adapted to change from a solid state at substantially a predetermined temperature to a liquid state, and (b) an effective amount (generally about 0.005 to about 0.5 percent preferably about 0.025 to about 0.05 percent by weight) of (1) one or more Group III compounds (pinacyanol iodide, quinaldine red, 1,1′-diethyl-2,2′-cyanine iodide, pinacyanol chloride, thionin, methylene blue, cresol red, chlorophenol red, neutral red iodide, neutral red chloride, crystal violet, acridin orange, toluidin blue O, Orasol Orange RLN?, Orasol Navy Blue?, Irgalith Red PR?, Fat Red BS?, Xylene Cyanol FF?, Rhodamine 6G?, Irgalith Magenta TCB?, Irgalith Pink TYNC?, Toluidin blue O?, Savinyl Green B?, Savinyl Blue RS?, purpurin, 3,3′-diethylthiadicarbocyanine iodide, cryptocyanine, Dicyanine A?, Merocyanine 540?, 4-(P-ethoxyphenylazo)-m-phenylene diamine monohydrochloride, Yellow Orange S?, Chrysoidin G?, fuchsin, aurintricarboxylic acid (ammonium salt), Victoria Blue R?, Pyronin G?, gallein Erythrosin Yellowish Blend?, chlorophenol blue, bromophenol blue, bromocresol purple, Coriphosphine O?, acriflavine, acridine orange, rhoduline violet, Alizarin cyanin 2R?, Alizarin Red S?, alcannin, Aurantia?, Direct Green G?, Fast Red Salt 3GL?, Fast Blue Salt BB?, Fast Garnet Salt GBC?, Carta Yellow G 180 o/o, Muroxide Savinyl Blue GLS?, Irgalith Blue GLSM?, phthalocyaline, Di Amingreen B?, Alizarin Blue S?, Celliton Blue Extra?, Janus Green, dimethyl yellow, Fast Yellow, Methyl red sodium salt, Alizarin yellow R?, Eriochrome black T?, Chromotrope 2R?, Ponceau 6R?, Brilliant Ponceau G/R/2R?, chromolan yellow, Sudan Red B?, Bismarck brown G?, Fat Black?, Resorcin Brown?, Benzofast pink 2BL?, Oil Red EGN?, Euroglaucine, Fuchsin NB?, parafuchsin, Patent Blue?, Irgalith Blue TNC?, Phloxin B?, fluorescein sodium salt, Rhodamine B base?, Eosinscarlet, Eosin Yellowish?, Erythrosin extrabluish, 4,5-dibromo fluorescein, ethyleosin, Phloxine, Cyanovin B?, chlorocresol green, pinacyanol bromide, 2-(p-dimethylaminostyryl)-1-1-ethyl pyridinium iodide, ethyl red, nigrosine, savinyl blue B?, Orasol Blue BLN?, Safranin O?, Azocarnun G?, Phenosafranine, Azocarmine BX?, Solophenyl Brilliant Blue BL?, Nile Blue A?, gallocyanine, gallanine blue, celestine blue, methylene green, Azure A/B/C?, Blue VIF Organol?, Alizarin, Nitrofast Green GSB?, quinalizarine, Oil Blue N?, Solvay purple, Ciba Blue?, Indigo synthetic?, Chromophtal Bordeaux RS?, acid Alizarin Red B?, 5-Aminoflourescein, Rose Bengal?, Martius Yellow?, Chicago Blue 6B?, Alcian Blue 8GX, cresyl violet, 4,4’Bis(dimethylamino)benzylhdrol, Zinc Pthalocyanine, Sudan III?, Pyronin Y?, Toluylene Blue?, Cresyl Violet perchlorate, Mendola’s Blue?, 3,3′-diethylthiadicarbocyanine iodide, Phosphine Dye?, Nitron?, Cresyl violet acetate, Ceres Orange R?, 4-phenylazo-1-naphthyl-amine, 4-(4-Dimethylamino-1-naphthylazo- 3-methoxybenzene sulfonic acid, Bindschedler’s Green?, and p-(p-dimethylamino phenylazo) benzoic acid and neocyanine) or in the alternative, (2) a similarly small amount of one or more of a Group I body of compounds consisting of the halogenated sulfonphthaleins and organic acids having a pK of less than about four, together with one or more of a Group II body of compounds consisting of the aminotriphenylmethanes and their soluble salts, 8-hydroxyquinoline, and the cyanines (with the proviso that if the Group II compounds consist solely of one or more aminotriphenylmethanes or their soluble salts, then Group I must be selected from one or more of the group consisting of oxalic acid, suitable soluble sulfonic acids, the tetrahalogenated sulfonphthaleins and the other known soluble organic acids having a pK1 of about 2 or less dissolved in the above-mentioned suitable solvents. Examples of Group I compounds suitable for use in this invention are one or more of the group consisting of oxalic acid, maleic acid, dichloroacetic acid, trichloroacetic acid, naphthalene sulfonic acid, benzensulfonic acid, chloroanilic acid, bromophenol blue, bromothymol blue, chlorophenol red, bromochlorophenol blue, bromocresol green, 3,4,5,6-tetrabromophenolsulfonphthalein, bromophenol red, chlorophenol blue, bromocresol purple, 2,4-dinitrobenzenesulphonic acid, and chlorocresol green. Examples of Group II compounds suitable for use in this invention are ethyl red, crystal violet, pararosaniline, pararosaniline acetate, basic fuchsin, 8-hydroxyquinoline, ethyl violet, brilliant green, pinacyanol chloride, and 3,3′-diethylthiodicarbocyanine. When Group III compounds are unavailable, preferred combinations of Group I compounds and Group II compounds include: (1) bromophenol Blue: basic fuchsin;(2) chlorophenol Blue: ethyl blue; (3) chlorophenol Red: ethyl res; (4) bromophenol Red: ethyl res; (5) bromochlorophenol Bleu: brilliant green. The weight ratio of Group I and Group II compounds should not exceed or equal to 3 to 1. In an effective amount, a Group III compound may be used either alone or in combination with a small amount (preferably less that 0.5 percent) from Group I or Group II compounds.

“The invention also contemplates a novel temperature-indicating device comprising (a) a flat or gradually curved heat-conducting carrier having one or more regions defined therein, preferably cavities, to determine a like number of predetermined temperatures at temperatures separated by a constant increment in a predetermined temperature range by means of a like number of different thermally-responsive compositions of matter, each cavity associated with one of the predetermined temperatures and each substantially without impurities, (b) if the novel compositions of our invention are not employed, an indicator means located at the bottom of each said cavities, (c) a transparent means in sealing engagement with a carrier means above each cavity and overlying each of said cavities to form an enclosure for each cavity between the walls of the cavity and the transparent means, and (d) one of said compositions of matter adapted to change from a solid to a liquid at substantially the predetermined temperature associated with said cavity, and in addition, substantially filling the cavity except for a substantially spherical void within said cavity and composition of matter. The novel temperature indicator device does not contemplate the necessity of employing the novel temperature-indicating compositions of matter, but can, in the alternative, employ the \”classical\” compositions of matter (compositions other than our novel compositions which generally change from opaque to transparent with a corresponding change in phase at a predetermined temperature). On the other hand, if the novel compositions of matter are employed, the indicator means in the novel temperature-indicating device may be eliminated. The invention allows for the use of the new device to replace ordinary opaque thermometers. This is possible when the backing material is colored or when bibulum paper is used as a cover or numerals are placed at the bottom of void spaces.

“In one aspect, this invention contemplates providing thermally-sensitive compositions which undergo a change of state, i.e., from solid to liquid, at precisely predetermined temperatures with a corresponding change of color visible to the naked eye; such temperature-sensitive compositions being solid solutions of certain organic compounds to be hereinafter described.”

“Another aspect is the invention’s use of an indicating device associated with novel compositions, so that it can quickly indicate the change in state of such matter and, therefore, the temperature of the subject.”

“Furthermore,” another aspect of the invention is directed at the provision of novel compositions or matter that may be applied to any other indication or measurement system other than temperature. The color change described in our invention can be used to indicate a fluid-to-solid, liquid-toliquid, or weakly-polar solvent induced either by pressure, radiation or other kinetic energy sources.

“In yet another aspect, the invention is directed toward the provision of a novel temperature-indicating device suitable as a disposable thermometer, in which each temperature-sensitive composition of matter used is substantially free of impurities so that said composition of matter upon complete melting has few nucleation sites and is not conducive to resolidification, i.e., the temperature-sensitive composition of matter has the property of stable undercooling and will remain liquid for at least several minutes up to several hours when subjected to a surrounding temperature that is somewhat below the freezing point of the composition.”

“And yet still another aspect, the present invention is directed toward the provision of a novel temperature-indicating device (comprising a flat or gradually curved heat conducting carrier means with one or more cavities therein and a transparent means in sealing engagement with said carrier means above the cavity) for use of so-called \”classical\” temperature-sensitive materials, e.g., compositions of matter commonly employed in disposable thermometers which change from opaque to become transparent upon a change in phase from solid to liquid, through the use of a substantially spherical void within said cavity containing the composition of matter determining the temperature to be indicated to magnify the presence of an indicator layer at the bottom of said cavity.”

“Finally and while some aspects of our invention will be apparent from the detailed description thereof infra,” says the inventor, “The overall object of our invention to provide generally useful improvements on change-of-state thermometers.”

“The details of the invention pertaining to the novel temperature-indicating device will become more evident from the detailed description to follow with reference to the appended drawings:”

“FIG. 2 is a partial plan view from the horizontal of a flat or gradually curved novel heat-conducting carrier having a cavity defined therein, which cavity forms an enclosure for a temperature-sensitive \”classical\” composition of matter therein when such cavity is covered by a transparent cover sheet means in sealing engagement with the carrier means overlying the heat-conducting carrier means and above the cavity; the figure also depicts a substantially spherical cavity inside the temperature-sensitive composition of matter;”

“FIG. 3. is a vertical section taken at line 3–3 in FIG. It is the partial plan view taken from above the cavity in FIG. 2. 2. When a painted material is located at the bottom of said cavity as an indicator means:

“FIG. 4. is a vertical section taken at line 4–4 in FIG. It is a partial view from the overhead cavity of FIG. 2. 2. When a painting material is magnified by a spherical cavity of the “classical” composition, after it has melted;

“FIG. “FIG.

“FIG. “FIG.

“FIG. 8 is a plan view of a temperature-indicating device from the horizontal (together with a plan view from the vertical of a label on said device) using the novel compositions of matter of this invention for indication of a temperature exceeding a predetermined safe limit. We will discuss the details in detail below.

“FIG. 9 is a three-dimensional cutaway view taken from a skewed angle on a thermometer. It contains a heat conductor means with a grid filled with cavities, and enclosed in a case where only the handle of that heat-conducting means protrudes.

“FIG. 11. is a partial horizontal plan view taken along line II-II of FIG. 10 reveals several cavities in the heat conductor carrier means. Each cavity is surrounded by transparent cover sheets and bottom transparent bottom plates.

“FIG. 12 is a plan view of a flat temperature-indicating device from the vertical without the use of a case, comprising a heat-conducting carrier means with a grid of cavities thereon; and”

“FIG. “FIG. 12 shows the heat-conducting carrier, cavities inside, transparent cover sheet, and a bottomplate.”

“FIG. 14 is a plan taken from the vertical view of a transparent support member to a disposable clinical thermometer. 10, or FIGS. 12-13.”

“FIG. FIG. 15 shows a plan view from the vertical end of the transparent support member. 14 except for sealing engagement, using a disposable thermometer like that shown in FIG. 10, with a Fahrenheit scale ranging from 96.0 to 104.8 degrees Fahrenheit, graduated in increments of 0.2 degrees Fahrenheit.

“FIG. 16. This is a plan view from the vertical end of FIG. 14 except for sealing engagement with the disposable thermometer shown in FIG. 10 with a Centigrade scale ranging from 35.5 to 40.4 degrees Centigrade, graduated in 0.1 degree Centigrade increments.

“FIG. “FIG.

“FIG. FIG. 18 shows a partial view of the horizontal as FIG. 17 with an additional layer of PIB at the lower edges of each cavity.

“Throughout the Detailed Description below, the terms \”novel thermally-responsive substance\”, \”novel thermally-responsive material\”, \”novel temperature-indicating compositions of matter\”, \”novel temperature-sensitive solid solutions\”, \”novel temperature-indicating solid solutions\”, and \”novel solid solutions\”, or variations thereof, are used interchangeably to denote the same novel materials of our invention. The terms “compositions or classic compositions of material” and ‘classical compositions or matter” can be used interchangeably to refer to compounds that change from opaque to transparent, with corresponding changes from the liquid to solid state or vice versa.

“1. “1.

It was discovered that certain organic compounds, to be described later, can form novel solid solutions. These solutions undergo a change of state from liquid to solid at predetermined temperatures, with corresponding changes in color visible by the naked eye. Solid solutions are well-known and refer to a homogenous mixture of two or more solids. The present invention contemplates novel solid solutions that are made up of multiple organic compounds, preferably three to four. They contain varying amounts of at least two of the compounds that form a solvent. Each novel solid solution experiences a rapid change in state at a predetermined temperature, or substantially thereabouts. A “change in color visible by the naked eye” refers to a change in wavelength of the luminous light from a source. This is visible to anyone with normal vision and eyesight if the intensity of the luminous flash surrounding the source is greater than or equal to 5 lumens per square feet (ft-c). This change in wavelength of luminous flux visible to the naked eye will most likely be less than 175 Angstroms and more preferably 500 Angstroms.

“It is important to emphasize that once a proposed solvent system (consisting one or more compounds), has been chosen, the compound(s), of the system, must be tested for Group I-III moiety stability (i.e. inertness and soluble in the compound(s). Routine testing is required, according to the expertise of those skilled in the art. This solvent system can only be used if the compound(s) of the solvent system dissolve the Group I-III moieties, and are inert towards them.

“While it is possible for a solvent system to contain only one compound in rare circumstances, most times (as those skilled with the art will understand) the temperature that must be determined cannot be easily obtained without mixing several organic compounds for its solvent system. Hence, for a temperature-indicating device, two or more related organic compound constituents in the solvent are especially helpful for measuring forty or more temperatures located at regular increments.”

It is evident from the above description that the selection and use of inert solvents towards organic moieties in novel composition of matter must be carefully considered. Not all organic compounds can be used for this purpose, and some may not be within the desired temperature range. Any solvent that is inert towards organic moieties, and in which organic moieties can be soluble in the liquid phase of the solvent is a suitable solvent. Simple alcohols and organic substances are sometimes more suitable than aromatic compounds. The organic compounds which are particularly adapted for the formations of solid solutions which can serve a novel temperature-indicating composition in accordance with the present invention are generally those which are aromatic weakly polar (e.g., compounds which are immiscible in water and have a dielectric constant less than about 35) or moderately polar aromatic organic compounds, as well as the requirements of organic moiety solublity and inertness towards the organic moieties. It has been found that the weakly polar and moderately polar aromatic compounds have an analogous chemical structure (e.g. homologs, analogs and optical isomers). These are used to prepare novel solid solutions for the purposes of the invention. It is also preferable for solvent solutions to have a linear, or substantially linear, temperature composition liquidous curve, especially over the desired temperature range, such as the human clinical temperature range. Exemplary weakly polar or nonpolar aromatic solvents are ortho-chloronitrobenzene, ortho-bromonitrobenzene, naphthalene, 2-ethoxybenzamide, 1-thymol, 2-naphthol, ortho-iodonitrobenzene, meta-iodonitrobenzene, para-iodonitrobenzene, para-chloronitrobenzene, meta-bromonitrobenzene, para-dibiomonitrobenzene and para-toluic acid. It is important to remember that not all solvents are suitable for all organic moieties. Also, not every solvent will work for every temperature. For a temperature to be measured, it is recommended to start investigating for the right temperature. Then select a suitable solvent system from the following compounds:

“(1) Moderately or weakly Polar Aromatic Compounds, i.e. compounds with a dielectric constant less than 35;”

“(2) water; or”

“(3) aromatic or aliphatic compounds other that (1)-(2), which are relevant to the temperatures to determine, and which are ‘inert to the Group I to III dyes.”

“The components of the novel compositions consist of:

“(1) A solvent (I) is a substance consisting of one or more substances that can be adapted to change from a stable state at substantially a temperature predetermined to a liquid state.

“(2) An indicator system (II) containing one or more substances that are different from (I), and characterized in that”

“(a), (II), is soluble in (I), when the latter is liquid phase.

“(b) (II), changes color visible to naked eye when (I), passes from the solid to liquid phase or from liquid to solid phase.”

“It is within the reach of skilled art practitioners to find a suitable solvent for a temperature range to be measured and for desired color change (choosing among the various Group I-III substances) to do so. This means that the solvent must be in towards the Group I-III compound and soluble in the liquid phase of said solvent.

“The solid solutions made from ortho-chloronitrobenzene and ortho-bromonitrobenzene have been found to be most preferable for use in temperature measurements in the clinical range within the aforesaid accuracy. As those who are skilled in the art will understand, any combination of aromatic solvents in which the organic moieties described above are soluble and stable may be used for thermometers. If they can be combined to form a homogenous solution, it is possible.

“Preferably, the novel composition of matter consists essentially:

“(A) A suitable solvent that is capable of changing from a solid at a predetermined temperature into a liquid, and

“(B). An effective amount of one of the suitable organic moieties, soluble in said solvent and adapted for changing the color of composition visible to naked eye upon change in state of solvent at substantially the predetermined temperatures.

“(1) A group III body of single compounds, consisting of the monoazo, diazo and triarylmethane classes of dyes, suitable colors from the following classes; azine and oxazine?, anthraquinone?, sulphonephthalein?, acridul?, azine?, thiazine?, anthraquinone?, indigold?, Cara Yellow G 180 o/o, Murexide, Irgalithblue GLSM?

“(2) combinations of:

“(a) One or more organic acids compounds, with a pK less than four and

“(3) combinations of”

“(a) One or more organic acids with a pK less than 2 and

“(b) one of more acid dyes, or acid indicators”

“(4) Mixtures of”

“(a) One or more organic acids compounds with a pK less than approximately 4”

“and”

“(b) one of the group I bodies of compounds”

“(5) combinations of”

“(a) One or more basic indicators or dyes and

“(b) one of the group I bodies of compounds”

“(6) combinations of”

“(a) One or more dyes containing a molecular structure that contains a lactone group.

“(b) One or more acids with a pK between 8 and 12.”

“The compounds listed in group III are classified according the Colour Index, 3rd edition (1971), published at the Society of Dyers and Colourists of Great Britain and Conn?s Biological Stains (9th ed 1977).

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