JP2007314659A - Thermosensitive color developing display composition for rubber product, rubber product with display function and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermosensitive color developing display composition for rubber product which, in spite of a simple composition, can integrally form on the surface of a rubber product a thermosensitive color developing display layer by heating displaying a variety of information such as characters; to provide a rubber product having a display function that is fabricated using the composition; and to provide a manufacturing method thereof. <P>SOLUTION: As the thermosensitive color developing display composition for rubber product, there is used a rubber composition containing a thermosensitive color-changing microcapsule that includes a thermosensitive color-changing composition, a diene type rubber component and a solvent and not containing a crosslinking agent for rubber. This composition is attached to the surface of an unvulcanized rubber product, the crosslinking agent for rubber contained in the above unvulcanized rubber product is allowed to spontaneously migrate into the thermosensitive color developing display composition for rubber product, the unvulcanized rubber product attached with the composition is heated to vulcanize it, and on the surface of the vulcanized rubber product there is formed the thermosensitive color developing display layer that is integrally laminated in the vulcanized state. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a temperature-sensitive color display composition for rubber products, a rubber product with a display function, and a method for producing the same. More specifically, a temperature-sensitive color display composition for rubber products that can integrally form a temperature-sensitive color display layer capable of displaying various information such as letters on the surface of a rubber product by heating despite the simple composition. The present invention relates to a rubber product with a display function produced using the composition, and a method for producing the same.

  Conventionally, product information such as the manufacturer name, date of manufacture, and production lot of a rubber product is usually recorded in a conspicuous narrow area of the rubber product. This is because it does not impair the appearance of the product, and as a recording method, for example, by attaching a plate engraved with product information on the inside of the molding die of the rubber product, the rubber product is limited. Product information is recorded in relief in the area. Therefore, the amount of information that can be recorded is limited, and all desired information cannot be recorded. For example, in a pneumatic tire, the product information as described above is recorded in a relief shape on the tire side portion. However, the tire side portion cannot afford to describe all of these product information in terms of space. Further, if the entire side surface of the tire is used, even if it can be described, it is impossible to frequently reattach the stamping plate to the mold so as to significantly hinder the production efficiency.

  In order to record more information on the rubber product without impairing the appearance, one thing is that printing technology can be used, and the product information recorded on the surface of the rubber product is In order not to impair the appearance of the rubber product, it is only necessary to make it appear only when it is desired to confirm the information. If you intend to achieve this purpose, if you print information on a rubber product using a thermochromic composition that develops or loses color due to changes in temperature, the information becomes visible by heating, In the state of use, it seems that information cannot be revealed and the appearance of the rubber product is not impaired. That is, it is expected that information can be confirmed by recording information on the surface of the rubber product using a temperature-sensitive color-changing rubber paint and heating the cured coating film as necessary.

  The temperature-sensitive color-changing rubber paint may have a structure in which microcapsules containing a known temperature-sensitive color-changing composition are mixed and dispersed in a rubber paint containing a rubber component, a rubber crosslinking agent, and a solvent. It is done. As a prior art suggesting such a configuration, a reversible thermochromic liquid composition has been disclosed (Patent Document 1).

  Patent Document 1 discloses a reversible thermochromic liquid composition comprising a thermochromic capsule containing a reversible thermochromic composition and a vehicle containing a resin. In this Patent Document 1, in addition to general synthetic resins, rubber components such as butyl rubber, cyclized rubber, chlorinated rubber, synthetic latex, liquid rubber, and natural rubber can be used as the resin. No specific composition as a paint is disclosed at all, and furthermore, no rubber paint suitable for integrally forming a temperature-sensitive color-changing layer on a rubber product is disclosed.

JP 2000-73050 A

  As a rubber coating derived from the above-mentioned prior art, the present inventors have a composition comprising a synthetic isoprene rubber, a rubber crosslinking agent (sulfur), a vulcanization accelerator, and a solvent (rubber volatile oil + toluene). A temperature-sensitive color changing microcapsule containing a known temperature-sensitive color-changing composition was mixed and dispersed in a rubber paint, and a temperature-sensitive color-developing display composition for rubber products was made as a trial product. This composition was applied to a sidewall portion of a commercially available pneumatic tire, heated, vulcanized and cured. As a result, the temperature-sensitive color display layer could be formed on the surface of the pneumatic tire, but it was found that there are mainly three problems to be solved.

  The first problem is that in the process of heating and vulcanizing and curing the rubber paint applied to the surface of the rubber product, bubble-like swelling is likely to occur in the coating film, and it is difficult to control the heating conditions. The second problem is that the adhesion of the temperature-sensitive color display layer to the surface of the pneumatic tire (rubber product) is not sufficient, and part of it may peel off over time. Furthermore, as a third problem, the surface on which the temperature-sensitive color display layer is formed and the other surface have different textures, and the temperature-sensitive color display layer is not colored by heat, It looks somewhat floating and the appearance is impaired.

  Accordingly, an object of the present invention is to solve the above-described problems and provide a technique capable of integrally forming a temperature-sensitive color display layer without impairing the appearance of the surface of a rubber product such as a pneumatic tire. There is.

As a result of diligent efforts, experiments, and examinations, the present inventor has obtained the following knowledge.
(1) A thermosensitive color-changing rubber paint is not attached to the surface of an existing rubber product and cured by vulcanization, but a temperature-sensitive color-changing rubber paint is applied to a rubber product before vulcanization (unvulcanized rubber product = green rubber molding). The green rubber molded body (hereinafter abbreviated as green) is heated and vulcanized in a molding die, and the paint is vulcanized and cured simultaneously with the curing of the green. As a result, the temperature-sensitive color display layer formed on the surface of the rubber product is integrated with the rubber product without causing defects such as swelling, and the adhesiveness becomes satisfactory.
(2) The compounding component of the rubber paint is basically the same as the compounding component constituting the green, and the rubber crosslinking agent necessary for vulcanization and curing is not contained in the paint itself. When a rubber paint having such a composition is attached to green, the crosslinking agent contained in the green migrates into the rubber paint, so that the rubber paint can be simultaneously crosslinked and cured under substantially the same composition conditions as green by heating the green. Can do. As a result, the temperature-sensitive color display layer formed on the surface of the rubber product is indistinguishable from the other parts, and the appearance is not impaired by providing the temperature-sensitive color display layer.

  The present invention has been made based on the above findings. That is, the temperature-sensitive color display composition for rubber products according to the present invention is attached to the surface of an unvulcanized rubber product and then heated together with the unvulcanized rubber product, whereby the unvulcanized rubber product is A temperature-sensitive color display composition for a rubber product, which forms a temperature-sensitive color display layer integrally laminated in a vulcanized state on the surface of a vulcanized rubber product, comprising: It contains a temperature-sensitive color-changing microcapsule, a diene rubber component, and a solvent, and does not contain a rubber crosslinking agent.

  As the temperature-sensitive color-changing composition, for example, a two-component composition composed of an acid developing substance and an acidic substance or a three-component composition obtained by adding a solvent to the two-component composition can be used.

  The rubber product is typically a pneumatic tire, in which case the unvulcanized rubber product corresponds to a green tire.

  The rubber product with a display function according to the present invention is a rubber product with a display function in which a temperature-sensitive color display layer is integrally laminated in a vulcanized state on the surface thereof, and the temperature-sensitive color display The layer is a vulcanized rubber layer made of a diene rubber, and temperature-sensitive color-changing microcapsules encapsulating the temperature-sensitive color-changing composition are dispersed therein.

  In the above structure, it is preferable that the temperature-sensitive color display layer constitutes information. Examples of the information include characters, numbers, symbols, other codes, and graphic forms.

  In the above configuration, as the rubber product, a pneumatic tire in which a temperature-sensitive color display layer is integrally formed on the surface of the sidewall portion is preferable.

  Moreover, the method for producing a rubber product with a display function according to the present invention is a method for producing a rubber product with a display function, in which a temperature-sensitive color display layer is integrally laminated in a vulcanized state on the surface, A temperature sensitive color-developing display composition for rubber products containing a temperature-sensitive color-changing microcapsule encapsulating a temperature-sensitive color-changing composition, a diene rubber component, and a solvent, and not containing a rubber crosslinking agent. An attaching step for attaching to the surface of the product, and a cross-linking agent transferring step for spontaneously transferring the cross-linking agent for rubber contained in the unvulcanized rubber product into the temperature-sensitive color display composition for rubber product; The unvulcanized rubber product to which the temperature sensitive color display composition for rubber products is adhered is heated to vulcanize the unvulcanized rubber product and to be integrated with the surface of the vulcanized rubber product in a vulcanized state. And a vulcanization step for forming a laminated thermosensitive color display layer And features.

  In the adhering step of the above-described configuration, the unvulcanized rubber product in the form of information such as letters, numbers, symbols, other codes, and figures is displayed on the temperature-sensitive color display composition for rubber products using a liquid jet printing apparatus. You may make it mark on the surface of.

  When the product information is recorded on the surface of the rubber product using the thermosensitive color display composition for rubber product of the present invention, the information can be manifested by applying heat only when it is desired to confirm, Product information can be easily confirmed when necessary. In addition, the temperature-sensitive color display layer on which information is recorded appears to be integrated with the rubber product at a normal environmental temperature, so that the appearance of the rubber product is not impaired.

  As described above, the temperature sensitive color display composition for rubber products according to the present invention is attached to the surface of an unvulcanized rubber product and then heated together with the unvulcanized rubber product, thereby A temperature sensitive color display composition for a rubber product which forms a temperature sensitive color display layer integrally laminated in a vulcanized state on the surface of the rubber product obtained by vulcanizing the rubber product, and has a temperature sensitive color change property. It includes a thermochromic capsule encapsulating the composition, a diene rubber component, and a solvent, and does not include a rubber crosslinking agent.

  The temperature-sensitive color-changing composition included in the microcapsules constituting the temperature-sensitive color-developing display composition of the present invention is a conventionally known temperature-sensitive color changing property as long as it is a composition that develops color at a predetermined temperature of room temperature or higher. The composition can be used and is not particularly limited. The temperature-sensitive color display composition used in the present invention is a two-component system comprising an acid developer and an acidic substance in that a high color density is obtained and the color type and color change temperature can be set relatively freely. More preferably, the composition is used. Further, a three-component composition obtained by adding a solvent for dissolving them to the two-component composition is more preferable.

  Examples of the acid developer include 3,3′-dimethoxyfluorane (yellow), 3-chloro-6-phenylaminofluorane (yellow orange), 3-diethyl-7,8-benzofluorane ( Peach), 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (blue purple), 3,3'-bis (p-dimethylaminophenyl) phthalide (green), 3-diethylamino-6- Examples thereof include substituted triphenylmethane or fluorane derivatives such as methyl-7-phenylaminofluorane (black), various indolylphthalide dyes, and spiropyrans. These acid developing substances may be used alone or in combination of two or more.

  Examples of the acidic substance that develops the acid developer include, for example, p-phenylphenol, bisphenol A, cresol, resorcin, chloroglycine, phenol resin oligomer, phenols such as β-naphthol, metal salts thereof or ammonium Salts, benzotriazoles such as 5-chlorobenzotriazole, 4-laurylaminosulfobenzotriazole, 5-butylbenzotriazole, dibenzotriazole, 2-oxybenzotriazole, 5-carboethoxybenzotriazole, or metal salts or ammonium salts thereof Furthermore, organic acids such as resorcinic acid, gallic acid, salicylic acid, benzoic acid, pyromellitic acid, stearic acid, p-toluenesulfonic acid, 1,5-naphthalenedisulfonic acid, or substitution induction thereof Or it can include a metal salt. These acidic substances may be used alone or in combination of two or more.

  Solvents that dissolve and coexist with the acid developer and acidic substance include, for example, alcohols such as octyl alcohol, dodecyl alcohol, myristyl alcohol, and oleyl alcohol, lanolin, lauryl stearate, octyl stearate, and palmitic acid. Esters such as benzyl acid, nonyl palmitate, glyceride palmitate, phenyl myristate, lauryl laurate, undecyl laurate, benzylideneaniline, benzylidene stearylamine, benzylidenephenylhydrazine, azomethines such as 1,4-bisphenylazomethine, In addition, amides such as acetamide, lauric acid amide, p-toluenesulfoamide, salicylic acid amide, coconut oil, beef tallow, naphthalene, parklene, etc. Kill. These solvents may be used alone or in combination.

  The reason why the thermochromic composition is encapsulated in microcapsules is to allow the two components or the three components to coexist. If it is not encapsulated in the microcapsule, the discoloration performance may be hindered due to elution of components out of the system or the entry of a discoloration inhibitor into the system, which is not preferable. Any known encapsulation method can be used as a method of encapsulating the thermochromic composition in a microcapsule to form a thermochromic microcapsule. For example, there are a coacervation method, an in situ polymerization method, an interfacial polymerization method, a liquid curing method, a spray drying method, and the like, and these methods may be used in combination of two or more.

  The temperature-sensitive discoloration capsule used in the present invention is the above-described interfacial polymerization method or in situ polymerization method using a thermosetting resin such as polyester resin, polyurethane resin, melamine resin, benzoguanamine resin, epoxy resin, etc. A thermosensitive color-changing composition is encapsulated and encapsulated by a known microencapsulation method. The inclusion body may be immersed in water in which a hydrophilic polymer such as polyvinyl alcohol, polyacrylate, gelatin, methylcellulose, alginic acid or the like is suspended, and the surface thereof may be further coated. This coating treatment can improve the durability of the microcapsules.

  The temperature-sensitive color-changing composition having the above-described configuration can set the color development temperature by selecting the type of the acidic substance.

  As the diene rubber component constituting the temperature-sensitive color display composition of the present invention, a rubber that is basically the same as the rubber component constituting the target rubber product may be used. For example, natural rubber (NR), It is possible to use synthetic isoprene rubber (IR), styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), isobutylene isoprene rubber (IIR), ethylene propylene rubber (EPDM), and oil-extended products of these rubbers. it can.

  In the temperature-sensitive color display composition of the present invention, the solvent in the composition is not particularly limited, but when the rubber product is a pneumatic tire, examples thereof include rubber volatile oil, toluene, xylene, cyclohexane and the like.

  The amount of the component in the temperature-sensitive color display composition of the present invention is 1 to 30 parts by weight of the thermosensitive discoloration microcapsule and 400 to 2000 parts by weight of the solvent with respect to 100 parts by weight of the diene rubber component. . The amount of the temperature-sensitive color-changing microcapsules is more preferably 5 to 20 parts by weight, and still more preferably 15 ± 2 parts by weight.

  The temperature-sensitive color-developing display composition of the present invention is characterized in that it does not contain a rubber crosslinking agent, but it does not preclude blending other additives as necessary. Basically, the same additives as those used in the target rubber product can be blended.

  In order to form a temperature-sensitive color display layer on the surface of a rubber product using the temperature-sensitive color display composition having the above structure, first, the temperature-sensitive color display composition is applied to the surface of an unvulcanized rubber product. Adhere. At this stage, a concentration gradient of the crosslinking agent is generated between the unvulcanized rubber product and the coating film of the thermosensitive color display composition, and the transition of the crosslinking agent to the coating film occurs during vulcanization. Therefore, when the unvulcanized rubber product to which the thermosensitive color display composition is adhered is heated in a molding die, the unvulcanized rubber product is vulcanized and vulcanized on the surface of the vulcanized rubber product. Thus, a temperature-sensitive color display layer that is integrally laminated is formed. Through this series of steps, the rubber product with a display function of the present invention is manufactured.

  The temperature sensitive color display composition can be attached using a conventionally known printing method such as printing or drawing with a brush, a known printing method, or a printing method using a known liquid jet printing apparatus. In order to attach more information such as numbers, letters, marks, etc. to the surface of the rubber product, it is preferable to use a liquid jet printing apparatus.

  It is important to set the color development temperature of the temperature-sensitive discoloration display layer formed on the surface of the rubber product to a temperature that exceeds the temperature range assumed in the normal use environment of the target rubber product. With this temperature setting, under normal operating conditions, the temperature-sensitive discoloration display layer is visually integrated with the rubber product, and it is not determined that the temperature-sensitive display layer is formed. There is no loss.

  By setting the developing temperature to the control temperature of various processes required when molding rubber products, not only the function of confirming product information by heating, which is the original purpose, but also various processes up to the completion of the manufacture of rubber products A function for checking whether the control temperature is appropriately performed can be used in combination.

  For example, in a pneumatic tire, a green tire is heated and vulcanized in a mold, then it is removed from the mold and allowed to cool, but the carcass cord contracts as it cools, which deforms the molded tire. In order to prevent this, the normal temperature gas is injected into the tire under pressure, the cord is cooled to below the glass transition point, and the vulcanized tire is allowed to cool until shrinkage does not occur. Since the temperature measurement is complicated in this post-vulcanization cooling treatment process, it is managed by the cooling time set empirically. This cooling time is set substantially excessively so as not to produce defective products. If this required cooling time can be accurately controlled, it can contribute to speeding up the manufacturing process.

  The setting of the cooling time in the post-vulcanization cooling treatment step is a secondary means for realizing the post-vulcanization cooling treatment, and precisely, the tire temperature is lower than the glass transition temperature of the carcass cord. It only has to be. The carcass cord is mainly composed of an organic fiber cord such as a nylon cord or a polyester cord. Since the glass transition temperature of nylon cord is about 50 ° C and the glass transition temperature of polyester cord is about 70 ° C, if the tire surface temperature after vulcanization falls below the respective glass transition temperature, the shrinkage of the carcass cord is corrected. Then, the cooling treatment after vulcanization can be finished. Accordingly, if the kind and combination of acidic substances are adjusted so that the color temperature of the thermosensitive color display composition of the present invention matches the material of the carcass cord, the post-vulcanization cooling treatment process at the time of tire manufacture It is possible to accurately control the time and contribute to shortening the manufacturing process.

  Examples of the present invention and comparative examples are shown below. Examples described below are merely examples for suitably explaining the present invention, and do not limit the present invention.

(Examples 1-3)
A pneumatic tire was used as a target rubber product on which the temperature-sensitive color display layer was formed. Three types of rubber compositions having the compositions shown in Table 1 below (units are parts by weight) were prepared as temperature-sensitive color display compositions. The temperature-sensitive color-changing microcapsules used were black at 80 ° C. or lower and colorless at temperatures above 80 ° C. (underlying rubber-colored white was visible). The acid developing substance was 3-diethylamino-6-methyl-7. -Phenylaminofluorane, an acidic substance encapsulating a two-component composition of bisphenol A.

  In preparing the composition, first, components other than the rubber volatile oil and toluene were mixed in advance. Next, a mixed solution of rubber volatile oil and toluene was prepared, and the mixed components were stirred and dissolved in this mixed solution to obtain a rubber composition in a paint state.

  Each temperature-sensitive color developing composition was included in a brush on the side wall of one green tire and applied in the form of letters. The drawn letters were “YG-E1” for the composition of Example 1, “YG-E2” for the composition of Example 2, and “YG-E3” for the composition of Example 3.

(Comparative Examples 1 and 2)
In the same manner as in the above examples, two types of rubber compositions having the compositions described in Table 1 below were prepared as the temperature sensitive color display composition. The temperature-sensitive discoloration microcapsules used were the same as those used in the examples.

  In the blank part of the side wall part of the green tire used in the Examples, the two types of temperature-sensitive color display compositions were included in a brush and applied in the form of letters. The drawn letters were “YG-C1” in the composition of Comparative Example 1 and “YG-C2” in the composition of Comparative Example 2.

  Green tires in which the compositions of the above Examples and Comparative Examples were applied to the side wall portions in the form of letters were placed in a molding die, heated, vulcanized and molded. The molding temperature was 180 ° C. and the molding time was 10 minutes.

The tire taken out from the molding die is immediately attached to the post-vulcanization processing apparatus for a pneumatic tire disclosed in Japanese Patent Laid-Open No. 7-24848, and air at 100 ° C. has an internal pressure of 2.0 kg / cm ² inside the tire. And then allowed to cool. At the same time as the color of each character disappeared, the tire was removed from the post-vulcanization treatment apparatus and left for 30 minutes. When the dimensions and shape of the tire after being allowed to stand were measured, the tire was not deformed in light of the standard product standards and was a good product.

  The sidewall portion of the tire was heated so that the surface temperature exceeded 80 ° C. As a result, the letters “YG-E1” were dark gray, “YG-E2” was light gray, and “YG-E3” and “YG-C2” were white. The developed color of the letters “YG-C1” was not seen. In addition, deformation of each character was not recognized.

  The tire was subjected to a constant strain fatigue test. First, a rubber sheet having a thickness of 0.2 cm was cut out from the tire sidewall portion so as to include a character portion, and a fatigue test sample was prepared using a JIS No. 3 dumbbell. A tensile strain rate of 0% to 80% was added to the dumbbell-shaped sample at a rate of 400 times at room temperature, and the state of each character part after 500,000 times was confirmed. As a result, as shown in Table 1, peeling was found in the character portion of Comparative Example 2.

  As described above, when the product information is recorded on the surface of the rubber product using the temperature-sensitive color display composition for the rubber product of the present invention, the information is applied only when it is desired to confirm, Product information can be revealed, and product information can be easily confirmed when necessary. In addition, the temperature-sensitive color display layer on which information is recorded appears to be integrated with the rubber product at a normal environmental temperature, so that the appearance of the rubber product is not impaired.

  Therefore, according to the present invention, a thermosensitive color display composition for rubber products, which can integrally form a heat discoloration display layer without impairing the appearance of the surface of a rubber product such as a pneumatic tire, the composition It is possible to provide a rubber product with a display function manufactured using a product and a manufacturing method thereof.

Claims (12)

After being attached to the surface of the unvulcanized rubber product, by being heated together with the unvulcanized rubber product, the unvulcanized rubber product is integrally integrated with the surface of the rubber product obtained by vulcanization. A temperature-sensitive color display composition for rubber products that forms a laminated temperature-sensitive color display layer,
A temperature-sensitive color display composition for rubber products, comprising a temperature-sensitive color-changing microcapsule encapsulating a temperature-sensitive color-changing composition, a diene rubber component, and a solvent, and not containing a rubber crosslinking agent.   The temperature-sensitive color-changing composition is a two-component composition comprising an acid developer and an acidic substance, or a three-component composition obtained by adding a solvent to the two-component composition. 2. A temperature-sensitive color display composition for rubber products as described in 1.   The temperature sensitive color display composition for rubber products according to claim 1 or 2, wherein the rubber product is a pneumatic tire and the unvulcanized rubber product is a green tire. On the surface of the rubber product with a display function, a temperature-sensitive color display layer is integrally laminated in a vulcanized state,
The temperature-sensitive color-developing display layer is a vulcanized rubber layer made of a diene rubber, and a temperature-sensitive color-changing microcapsule containing a temperature-sensitive color-changing composition is dispersed therein. With rubber products.   The rubber product with a display function according to claim 4, wherein the temperature-sensitive color display layer constitutes information.   6. The rubber product with a display function according to claim 5, wherein the information is at least one selected from characters, numbers, symbols, other codes, and figures.   5. The temperature-sensitive color-changing composition is a two-component composition comprising an acid developing substance and an acidic substance, or a three-component composition obtained by adding a solvent to the two-component composition. The rubber product with a display function according to any one of -6.   The rubber product with a display function according to any one of claims 4 to 7, which is a pneumatic tire in which a temperature-sensitive color display layer is integrally formed on a surface of the sidewall portion. A method for producing a rubber product with a display function in which a temperature sensitive color display layer is integrally laminated in a vulcanized state on its surface,
A temperature sensitive color-developing display composition for rubber products containing a temperature-sensitive color-changing microcapsule encapsulating a temperature-sensitive color-changing composition, a diene rubber component, and a solvent, and not containing a rubber crosslinking agent. An adhesion process to adhere to the surface of the product;
A cross-linking agent transition step for spontaneously transferring the cross-linking agent for rubber contained in the unvulcanized rubber product into the temperature-sensitive color display composition for the rubber product;
The unvulcanized rubber product to which the temperature sensitive color display composition for rubber products is attached is heated to vulcanize the unvulcanized rubber product and to be integrated with the surface of the vulcanized rubber product in a vulcanized state. A vulcanization step of forming a temperature-sensitive color display layer laminated on the substrate,
A method for producing a rubber product with a display function, comprising:   The said adhesion process WHEREIN: The said temperature-sensitive color display composition for rubber products is marked on the surface of the said unvulcanized rubber product in the form of information using a liquid jet printing apparatus. Manufacturing method of rubber products with display function.   The method for producing a rubber product with a display function according to claim 10, wherein the information is at least one selected from characters, numbers, symbols, other codes, and figures.   10. A two-component composition comprising an acid developer and an acidic substance or a three-component composition obtained by adding a solvent to the two-component composition is used as the temperature-sensitive color-changing composition. The manufacturing method of the rubber product with a display function of any one of -11.