JP2007224245A - Puncture sealing material for tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a puncture sealing material for tire exhibiting sealing performance comparable to conventional puncture sealing material for tire and having relatively low viscosity and excellent storage stability. <P>SOLUTION: The puncture sealing material for tire contains at least one kind of polyolefin emulsion selected from polyethylene emulsion, polypropylene emulsion, ethylene-propylene copolymer emulsion and polybutene emulsion and 90-500 pts.mass (based on 100 pts.mass of the solid component of the polyolefin emulsion) of an antifreezing agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a tire puncture seal material.

Conventionally, as a tire puncture sealing material for repairing a punctured tire, a natural rubber latex blended with a tackifying resin emulsion and an antifreezing agent has been frequently used (for example, see Patent Documents 1 and 2).
This tire puncture sealant is a latex in which natural rubber particles and tackifying resin particles are repelled by ionic repulsion in an aqueous solution of an antifreeze and dispersed.
As this type of tire puncture sealant, for example, “a puncture sealant for a tire containing at least a natural rubber latex, a tackifying resin emulsion and an antifreezing agent, wherein the solid content A of the natural rubber latex and the tackifying resin are used. The solid content A of the natural rubber latex is 30 to 60 parts by weight with respect to 100 parts by weight of the total solids, which is the sum A + B + C of the solids B of the emulsion and the cryoprotectant C. The content of component B was 10 to 30 parts by weight, the content of the antifreezing agent C was 20 to 50 parts by weight, and an aromatic modified terpene resin was used as the tackifying resin of the tackifying resin emulsion A tire puncture sealant characterized by the above is known (see Patent Document 1).

  In addition, tire puncture seal materials using synthetic rubber latex such as acrylonitrile-butadiene rubber (NBR) latex and styrene-butadiene rubber (SBR) latex have been proposed (see Patent Documents 3 to 4).

  The tire puncture sealing material as described above is usually injected into the tire from the air filling portion of the tire, filled with air up to a predetermined air pressure, and then traveled to reach the puncture hole. Then, an aggregate of rubber particles is formed by the compressive force and shearing force received when the tire is in rotating contact with the ground, and the puncture hole is sealed.

  The tire puncture frequency recently used is usually said to be once every few years, and the frequency with which sealants are actually used is very low. Therefore, the tire puncture sealant is not only excellent in sealability but also important in performance that can withstand long-term storage in the vehicle.

JP 2004-035867 A Japanese Patent No. 3210863 JP 2005-170973 A JP 2001-62934 A

However, the natural rubber latex tire puncture seal materials described in Patent Documents 1 and 2 have low storage stability, and, for example, have a life of about one year when left in an automobile trunk, and if that is exceeded, There are problems such as solidification or gelation, and the fluidity is remarkably lowered, making it impossible to inject into a punctured tire.
Natural rubber latex tire puncture seal materials usually have an irritating odor because ammonia is used to stabilize the natural rubber latex. Furthermore, since the pH is adjusted to about 9.0 to 12.0, there is a problem that the steel cord in the tire is corroded by rust, and may cause inflammation when touching the skin.
On the other hand, Patent Document 1 describes that if so-called deproteinized natural rubber latex is used, the decay of natural rubber latex can be suppressed with less ammonia. However, the problem of odor and corrosion of steel cords remains even when deproteinized natural rubber latex is used. In addition, complicated manufacturing processes such as deproteinization are required.

Although the NBR latex tire puncture sealant described in Patent Document 3 is excellent in storage stability, it has a relatively high viscosity, so that a load is applied to the pump when it is injected into the tire, or it remains in the nozzle after the injection. There is a risk that the tire puncture sealant will harden and become clogged. Furthermore, when the temperature is extremely low, such as during the severe cold season or during snowfall, the viscosity becomes higher and the above-mentioned problem is likely to occur when injecting. In addition, since ammonia is usually adjusted to pH 9.0 to 11.0 for stabilization of NBR latex, as with natural rubber latex tire puncture seal materials, generation of irritating odors, steel cord There are problems such as corrosion and irritation when touching the skin.
In addition, since the SBR latex tire puncture sealant is also adjusted to pH 9.0 to 11.0 using ammonia for stabilization, there is a problem similar to that of the NBR latex tire puncture sealant.

  Accordingly, an object of the present invention is to provide a tire puncture sealing material having a sealing property equivalent to that of a conventional tire puncture sealing material, having a relatively low viscosity, and excellent storage stability. It is another object of the present invention to provide a tire puncture seal material that has no irritating odor and hardly corrodes a steel cord.

When the present inventor contains a polyolefin-based emulsion and an antifreezing agent, the tire puncture sealant has a sealing property equivalent to that of a conventional tire puncture sealant, has a relatively low viscosity, and has excellent storage stability. I found out.
Furthermore, the present inventor has found that when the hydrogen ion index (pH) of the tire puncture sealant is 5.5 to 8.5, the tire puncture sealant has no irritating odor and hardly corrodes the steel cord. did.
The present inventor completed the present invention based on these findings.

That is, the present invention provides the following (1) to (8).
(1) A tire puncture sealant containing a polyolefin-based emulsion and an antifreezing agent.
(2) The tire puncture sealing material according to (1), wherein the polyolefin-based emulsion is at least one emulsion selected from the group consisting of polyethylene emulsion, polypropylene emulsion, ethylene-propylene copolymer emulsion and polybutene emulsion. .
(3) The tire puncture sealant according to (1) or (2), wherein the antifreezing agent is contained in an amount of 90 to 500 parts by mass with respect to 100 parts by mass of the solid content of the polyolefin emulsion.
(4) The tire puncture sealing material according to any one of (1) to (3), further containing a tackifier.
(5) The tire puncture sealant according to (4), wherein the tackifier is an emulsion obtained by emulsifying a resin.
(6) The tire puncture seal material according to (4) or (5), wherein the tackifier includes at least one selected from the group consisting of a rosin resin, a terpene resin, and a hydrogenated terpene resin.
(7) The tire puncture seal according to any one of (4) to (6), wherein the solid content of the tackifier is 50 to 250 parts by mass with respect to 100 parts by mass of the solid content of the polyolefin-based emulsion. Wood.
(8) The tire puncture sealant according to any one of (1) to (7), wherein the hydrogen ion index is 5.5 to 8.5.

The tire puncture seal material of the present invention has a sealing property equivalent to that of a conventional tire puncture seal material, has a relatively low viscosity, and is excellent in storage stability.
Furthermore, when the hydrogen ion index of the tire puncture sealant of the present invention is 5.5 to 8.5, there is no irritating odor and the steel cord is hardly corroded.

Hereinafter, the present invention will be described in more detail.
The tire puncture sealing material of the present invention contains a polyolefin-based emulsion and an antifreezing agent.

The polyolefin emulsion used for the tire puncture seal material of the present invention is not particularly limited, and a conventionally known polyolefin emulsion can be used.
Examples of the polyolefin-based emulsion include those in which a polyolefin having a hydrophilic group introduced is dispersed in water. Examples of the hydrophilic group include a carboxy group, a sulfonic acid group, a phosphoric acid group, a hydroxy group, and an amino group.
Specific examples of the polyolefin emulsion include polyethylene emulsion, polypropylene emulsion, ethylene-propylene copolymer emulsion, and polybutene emulsion.
These may be used alone or in combination of two or more.

The polyethylene emulsion is not particularly limited, and a conventionally known polyethylene emulsion can be used.
Examples of the polyethylene emulsion include those in which a polyethylene having a hydrophilic group introduced is dispersed in water. Examples of the hydrophilic group include a carboxy group, a sulfonic acid group, a phosphoric acid group, a hydroxy group, and an amino group.

  Examples of the emulsifying dispersant include nonionic surfactants, anionic surfactants, cationic surfactants, and zwitterionic surfactants. Among these, nonionic surfactants are preferable because they are neutral and have a low odor.

  Specific examples of the nonionic surfactant include, for example, fatty acid sorbitan esters, polyoxyethylene fatty acid sorbitans, polyoxyethylene higher alcohol ethers, polyoxyethylene-propylene higher alcohol ethers, polyoxyethylene fatty acid esters, polyoxyethylene. Examples thereof include alkylphenol, polyoxyethylene alkylamine, and polyoxyethylene-polyoxypropylene block polymer.

  Specific examples of the anionic surfactant include, for example, fatty acid alkali metal salts, alkyl sulfates, alkyl ether sulfates, alkylbenzene sulfonates, N-acyl-N-methyl taurates, and dialkyl sulfosuccinates. N-alkyl-N, N-dimethyl oxide and the like.

  Specific examples of the cationic surfactant include quaternary ammonium salts such as alkylamine acetate and alkyltrimethylammonium chloride.

  Specific examples of the zwitterionic surfactant include dimethylalkyl betaine and alkylamide betaine.

Further, as the emulsifying dispersant, a reactive surfactant having a reactive double bond in the surfactant molecule; a water-soluble polymer such as polyvinyl alcohol and starch can be used.
The above emulsifying dispersants may be used alone or in combination of two or more.

As said polyethylene, the thing whose melting | fusing point is 90-150 degreeC is preferable, and the thing whose weight average molecular weight is 1,000-1,000,000 is preferable.
In the present specification, the melting point refers to a value measured by a softening point test method (ring ball method) defined in JIS K2207.

  In the present invention, commercially available products may be used as the polyethylene emulsion. Specific examples thereof include Johnson Polymer JW-150, Clariant Wax Dispersion W867, and San Nopco Nopcoat. PEM-17, PE401 manufactured by Naruse Chemical Co., etc., can be mentioned.

The said polypropylene emulsion is not specifically limited, A conventionally well-known polypropylene emulsion can be used.
Examples of the polypropylene emulsion include those in which a polypropylene having a hydrophilic group introduced is dispersed in water. Examples of the hydrophilic group include a carboxy group, a sulfonic acid group, a phosphoric acid group, a hydroxy group, and an amino group.

Moreover, what the polypropylene was disperse | distributed in water with the emulsification dispersing agent can also be used as said polypropylene emulsion.
The emulsifying dispersant is the same as that used for the polyethylene emulsion described above.

  As said polypropylene, the thing whose melting | fusing point is 90-150 degreeC is preferable, and the thing whose weight average molecular weight is 1,000-1,000,000 is preferable.

  In the present invention, commercially available products may be used as the polypropylene emulsion, and specific examples thereof include PP emulsion manufactured by Maruyoshi Kasei Co., Ltd.

The ethylene-propylene copolymer emulsion is not particularly limited, and a conventionally known ethylene-propylene copolymer emulsion can be used.
Examples of the ethylene-propylene copolymer emulsion include those in which an ethylene-propylene copolymer having a hydrophilic group introduced is dispersed in water. Examples of the hydrophilic group include a carboxy group, a sulfonic acid group, a phosphoric acid group, a hydroxy group, and an amino group.

Moreover, what the ethylene-propylene copolymer was disperse | distributed in water with the emulsification dispersing agent can also be used as said ethylene-propylene copolymer emulsion.
The emulsifying dispersant is the same as that used for the polyethylene emulsion described above.

  As the ethylene-propylene copolymer, those having a melting point of 90 to 150 ° C. are preferable, and those having a weight average molecular weight of 1,000 to 1,000,000 are preferable.

  In the present invention, a commercially available product may be used as the ethylene-propylene copolymer emulsion, and specific examples thereof include HS manufactured by Regitex.

The polybutene emulsion is not particularly limited, and a conventionally known polybutene emulsion can be used.
Examples of the polybutene emulsion include those in which a polybutene having a hydrophilic group introduced is dispersed in water. Examples of the hydrophilic group include a carboxy group, a sulfonic acid group, a phosphoric acid group, a hydroxy group, and an amino group.

Moreover, what the polybutene was disperse | distributed in water with the emulsification dispersing agent can also be used as said polybutene emulsion.
The emulsifying dispersant is the same as that used for the polyethylene emulsion described above.

  Specifically, as the polybutene emulsion, for example, a polymer having a structural unit based on a phosphorylcholine-like group-containing methacrylic acid ester represented by the following formula (1) (hereinafter referred to as polymer (A)). Preferable examples include an emulsion of polybutene and water.

The formula (1), R ^1, - (CH _{2) m} - or _{- (CH 2 CH 2 O)} n -CH 2 CH 2 - and is, m, n are each is an integer from 1 to 10 .

Specific examples of the monomer represented by the above formula (1) include 2-methacryloyloxyethyl-2 ′-(trimethylammonio) ethyl phosphate, 3-methacryloyloxypropyl-2 ′-(trimethylammonio). ) Ethyl phosphate, 4-methacryloyloxybutyl-2 '-(trimethylammonio) ethyl phosphate, 2-methacryloyloxyethoxyethyl-2'-(trimethylammonio) ethyl phosphate, 2-methacryloyloxydiethoxyethyl-2'- (Trimethylammonio) ethyl phosphate and the like. These may be used alone or in combination of two or more.
Among these, 2-methacryloyloxyethyl-2 ′-(trimethylammonio) ethyl phosphate is preferable.

The polymer (A) is a homopolymer obtained by polymerizing the monomer represented by the formula (1) alone or a copolymer obtained by copolymerizing another copolymerizable vinyl monomer.
Examples of other copolymerizable vinyl monomers include styrene monomers such as styrene, methylstyrene, and chlorostyrene; vinyl ether monomers such as vinyl acetate and vinyl propionate; methyl (meth) acrylate, ethyl (meth) acrylate, Alkyl (meth) acrylate monomers such as n-butyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, 2-ethylhexyl (meth) acrylate; (meth) acrylic acid; 2-hydroxyethyl (meth) Functional group-containing (meth) acrylates such as acrylate and glycerol (meth) acrylate; polyalkylene glycol (meth) acrylates such as polyethylene glycol (meth) acrylate and polypropylene glycol (meth) acrylate DOO; (meth) acrylic acid amide, N- vinylpyrrolidone, and nitrogen-containing monomers such as acrylonitrile and the like. These may be used alone or in combination of two or more.
Among these, a (meth) acrylate monomer is preferable from the viewpoint of controlling the balance between the hydrophilicity and the hydrophobicity of the polymer (A) and copolymerization during the reaction. From the viewpoint of the stability of the polybutene emulsion, a (meth) acrylate monomer having an alkyl chain having 1 to 24 carbon atoms is preferred.

  When the monomer represented by the formula (1) is copolymerized with another monomer, the content of the monomer represented by the formula (1) is preferably 1 to 90% by mass, and more preferably 5 to 80% by mass. . If it is this range, the characteristic of the monomer represented by Formula (1) and another monomer can fully express.

  The polymer (A) has an effect as a dispersant or an emulsifier for polybutene in water, and also has an effect as a stabilizer for fillers, drugs, etc. added as necessary. On the other hand, it is inert and less irritating and can be used safely.

The polymer (A) is, for example, bulk polymerization, suspension polymerization, emulsion polymerization, solution of each monomer component described above in the presence of a radical polymerization initiator in an inert gas atmosphere such as nitrogen, carbon dioxide, and helium. It can be obtained by polymerization by a known method such as polymerization.
The polymerization initiator is not particularly limited. For example, benzoyl peroxide, lauroyl peroxide, diisopropyl peroxydicarbonate, t-butylperoxy-2-ethylhexanoate, t-butylperoxypivalate, t-butylperoxy Examples thereof include diisobutyrate, azobisisobutyronitrile, azoisobisdimethylvaleronitrile, persulfate, and persulfate-bisulfite system.
As for the preparation amount of the said polymerization initiator, 0.0001-10 mass parts is preferable with respect to 100 mass parts of monomer components, and 0.01-5 mass parts is more preferable.
The polymerization temperature is preferably 20 to 100 ° C., and the polymerization time is preferably 0.5 to 72 hours.

  The weight average molecular weight of the polymer (A) is preferably 1,000 to 5,000,000, and preferably 10,000 to 1,000,000 from the viewpoint of miscibility with polybutene and water and the viscosity of the blend. More preferred.

The polybutene includes isobutylene homopolymer, copolymer of isobutylene and its isomer, copolymer of isobutylene and other olefin, copolymer of isobutylene, its isomer and other olefin, and hydride thereof. It is. These may be used alone or in combination of two or more. Among these, hydrogenated polybutene, which is a hydride, is preferable because it is less susceptible to oxidative degradation due to heat and light.
Examples of the isomer include 1-butene, cis-2-butene, and trans-2-butene.

The polybutene is produced, for example, by polymerizing a gas mixture containing isobutylene or the like using an acid catalyst such as aluminum chloride, and adding hydrogen as necessary.
When producing polybutene, a high-viscosity polybutene can be produced from a low-viscosity light polybutene by adjusting the amount of catalyst added and the reaction temperature.
Polybutene is a highly safe material, is an oily polymer that is inert to biological components, and can impart sealing properties.

The polybutene is preferably liquid or viscous, and liquid polybutene is particularly preferable for preparing an emulsion.
The number average molecular weight of the polybutene is preferably from 150 to 4000 from the viewpoint of being liquid or viscous.

1-50 mass% is preferable and, as for content of a polymer (A), 2-40 mass% is more preferable. Within this range, the stability of the emulsion is excellent and the viscosity does not become too high.
10-90 mass% is preferable, and, as for content of polybutene, 20-80 mass% is more preferable.
The water content is preferably 9 to 89% by mass.

The emulsion preferably further contains a surfactant. The stability of the emulsion can be improved by adding a surfactant.
Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, and zwitterionic surfactants. These may be used alone or in combination of two or more.
In the above surfactant, the preferred carbon chain length of the fatty acid and alkyl group is 8 to 18 carbon atoms.

  Specific examples of the nonionic surfactant include, for example, fatty acid sorbitan esters, polyoxyethylene fatty acid sorbitans, polyoxyethylene higher alcohol ethers, polyoxyethylene-propylene higher alcohol ethers, polyoxyethylene fatty acid esters, polyoxyethylene. Examples thereof include alkylphenol, polyoxyethylene alkylamine, and polyoxyethylene-polyoxypropylene block polymer.

  Specific examples of the anionic surfactant include, for example, fatty acid alkali metal salts, alkyl sulfates, alkyl ether sulfates, alkylbenzene sulfonates, N-acyl-N-methyl taurates, and dialkyl sulfosuccinates. N-alkyl-N, N-dimethyl oxide and the like.

Specific examples of the cationic surfactant include quaternary ammonium salts such as alkylamine acetate and alkyltrimethylammonium chloride.
Specific examples of the zwitterionic surfactant include dimethylalkyl betaine and alkylamide betaine.

  0.01-10 mass% is preferable and, as for the addition amount of the said surfactant, 0.1-2 mass% is more preferable. Within this range, the effect of adding a surfactant can be sufficiently obtained, and the safety such as less irritation to the skin is also excellent.

The emulsion may contain various additives as long as the object of the present invention is not impaired.
Specific examples of the additives include oily materials such as vegetable oils, animal fats, waxes, waxes, paraffins other than polybutene, petrolatum, fatty acid esters, higher fatty acids, higher alcohols, titanium oxide, zinc oxide, talc. , Inorganic compounds such as silica, kaolin, sodium carbonate, borax, organic solvents such as ethanol, isopropanol, ethylene glycol, propylene glycol, glycerin, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, ethylene oxide and propylene Other water-soluble polymers such as a block copolymer of oxide and a copolymer of maleic anhydride and methyl vinyl ether are included.

  The manufacturing method of the said emulsion is not specifically limited, It can carry out by a well-known method. For example, polybutene, polymer (A), water, and optionally surfactants and various additives are emulsified in a temperature range of room temperature to 90 ° C. using an emulsifier or kneader such as a homogenizer or a homomixer. Can be manufactured.

  In the present invention, commercially available products may be used as the polybutene emulsion, and specific examples thereof include Emmawet 10E, Emmawet 30E (both manufactured by NOF Corporation) and the like.

  Specific examples of the antifreezing agent used in the tire puncture seal material of the present invention include, for example, ethylene glycol and propylene glycol. These may be used alone or in combination of two or more.

The content of the antifreeze agent is preferably 90 to 500 parts by mass, and 120 to 350 parts by mass with respect to 100 parts by mass of the solid content of the polyolefin emulsion, from the viewpoint of excellent performance for preventing the tire puncture sealant from freezing. Part is more preferable, and 140 to 300 parts by mass is still more preferable.
Here, the solid content of the polyolefin-based emulsion means the total of the components contained in the polyolefin-based emulsion excluding water and the solvent.

The tire puncture sealant of the present invention preferably further contains a tackifier from the viewpoint that excellent sealing properties can be obtained.
Specific examples of the tackifier include rosin resins such as rosin esters, polymerized rosin esters, and modified rosins; terpene resins such as terpene phenols and aromatic terpenes; hydrogenated hydrogenated terpene resins. Examples include terpene resins; phenol resins; xylene resins. In addition, an emulsion obtained by emulsifying these resins is one of preferred embodiments from the viewpoint of excellent compatibility with the polyolefin emulsion. These may be used alone or in combination of two or more.
Among these, a tackifier containing at least one selected from the group consisting of rosin-based resins, terpene-based resins, and hydrogenated terpene-based resins is preferable from the viewpoint of excellent sealing properties.

The content of the solid content of the tackifier is preferably 50 to 250 parts by mass, more preferably 70 to 220 parts by mass with respect to a total of 100 parts by mass of the solid content of the polyolefin-based emulsion, from the viewpoint of excellent sealing properties. preferable.
Here, the solid content of the tackifier means the total of the components contained in the tackifier excluding water and the solvent.

  In addition to the components described above, the tire puncture seal material of the present invention is optionally filled with a filler, an anti-aging agent, an antioxidant, a pigment (dye), a plasticizer, a thixotropic agent, an ultraviolet absorber, a flame retardant, Various additives such as a surfactant (including a leveling agent), a dispersant, a dehydrating agent, and an antistatic agent can be contained.

  Examples of the filler include organic or inorganic fillers having various shapes. Specifically, for example, fumed silica, calcined silica, precipitated silica, ground silica, fused silica; diatomaceous earth; iron oxide, zinc oxide, titanium oxide, barium oxide, magnesium oxide; calcium carbonate, magnesium carbonate, zinc carbonate; Waxite clay, kaolin clay, calcined clay; carbon black; these fatty acid treated products, resin acid treated products, urethane compound treated products, fatty acid ester treated products and the like.

Specific examples of the anti-aging agent include hindered phenol compounds.
Specific examples of the antioxidant include butylhydroxytoluene (BHT) and butylhydroxyanisole (BHA).

  Specific examples of the pigment include inorganic pigments such as titanium oxide, zinc oxide, ultramarine, bengara, lithopone, lead, cadmium, iron, cobalt, aluminum, hydrochloride, sulfate, etc .; azo pigment, phthalocyanine pigment, quinacridone Pigment, quinacridone quinone pigment, dioxazine pigment, anthrapyrimidine pigment, anthanthrone pigment, indanthrone pigment, flavanthrone pigment, perylene pigment, perinone pigment, diketopyrrolopyrrole pigment, quinonaphthalone pigment, anthraquinone pigment, thioindigo pigment, benzimidazolone Examples thereof include organic pigments such as pigments, isoindoline pigments, and carbon black.

  Specific examples of the plasticizer include diisononyl phthalate (DINP); dioctyl adipate, isodecyl succinate; diethylene glycol dibenzoate, pentaerythritol ester; butyl oleate, methyl acetylricinoleate; tricresyl phosphate, trioctyl phosphate An adipate propylene glycol polyester, an adipate butylene glycol polyester, and the like.

  Specific examples of the thixotropic agent include aerosil (manufactured by Nippon Aerosil Co., Ltd.), disparon (manufactured by Enomoto Kasei Co., Ltd.), and the like.

Specific examples of the flame retardant include chloroalkyl phosphate, dimethyl / methylphosphonate, bromine / phosphorus compound, ammonium polyphosphate, neopentyl bromide-polyether, brominated polyether, and the like.
Specific examples of the antistatic agent include quaternary ammonium salts; hydrophilic compounds such as polyglycols and ethylene oxide derivatives.

  The method for producing the tire puncture sealant of the present invention is not particularly limited. For example, the polyolefin emulsion and the antifreeze agent are added to the reaction vessel, and if necessary, the tackifier and various additives are mixed under reduced pressure. A method of sufficiently kneading using a stirrer such as a mixer may be mentioned.

The tire puncture sealant of the present invention preferably has a pH of 5.5 to 8.5. When the pH is within this range, the steel cord is hardly corroded.
Usually, since the tire puncture sealant of the present invention is excellent in stability when the pH is within the above range, it is not necessary to add ammonia or the like for stabilization. Therefore, there is no irritating odor. In view of these characteristics, the tire puncture sealant of the present invention preferably has a pH of 6.0 to 8.0, and more preferably 6.5 to 8.0.

An acid or a base may be added to the tire puncture sealant of the present invention to adjust the pH within the above range.
The acid is not particularly limited, and specific examples include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, phosphorous acid, acetic acid, propionic acid, formic acid, butyric acid, lactic acid, malic acid, and citric acid. Organic acids such as These may be used alone or in combination of two or more.
The base is not particularly limited, but preferably has no irritating odor, and specific examples thereof include sodium hydroxide, potassium hydroxide, and tertiary amine. These may be used alone or in combination of two or more. Among these, triethylamine is preferable from the viewpoints of safety and water resistance after sealing.

Hereinafter, the usage method of the tire puncture sealing material of this invention is demonstrated. However, the method of using the tire puncture seal material of the present invention is not limited to the following method.
First, the tire puncture seal material of the present invention is injected into the tire from the air filling portion of the tire. The method for injecting the tire puncture sealant of the present invention into the tire is not particularly limited, and a conventionally known method can be used, and examples thereof include a method using a syringe, a spray can and the like. The amount of the tire puncture sealant injected into the tire is not particularly limited, and is appropriately selected according to the size of the puncture hole.
Next, air is filled up to a predetermined air pressure.
Then, drive the car. Agglomerates such as polyolefin particles can be formed by the compressive force and shear force received when the tire is in contact with the rotating ground, and the puncture hole can be sealed.

The tire puncture seal material of the present invention has a sealing property equivalent to that of a conventional tire puncture seal material, has a relatively low viscosity, and is excellent in storage stability.
Furthermore, when the hydrogen ion index of the tire puncture sealant of the present invention is 5.5 to 8.5, there is no irritating odor, it is difficult to corrode the steel cord, and there is a possibility of causing inflammation even when contacted with the skin. Low.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
<Preparation of NBR latex tire puncture sealant (Formulation Example 1)>
An NBR latex tire puncture sealant was prepared in accordance with the method of Example 1 described in JP-A-2005-170973.
Specifically, the following materials (1) to (5) were mixed using a stirrer to obtain an NBR latex tire puncture sealant (pH 9.5) of Formulation Example 1.
(1) Rubber latex: NBR latex (Nipol, manufactured by Nippon Zeon Co., Ltd.), 65% by mass in the puncture sealing agent
(2) Nylon fiber: content 2% by mass in the puncture sealant, fiber length 2 to 7 mm, fiber thickness 5 to 30 μm
(3) Antifreezing agent: 25% by mass in ethylene glycol and puncture sealing agent
(4) Thickener: Smectite clay, content in puncture sealing agent: 2% by mass
(5) Other: Water as the balance

<Examples 1-32 and Comparative Examples 1-2>
The components shown in Table 1 below were mixed using a stirrer with the composition (parts by mass) shown in Table 1 to obtain tire puncture seal materials shown in Table 1.
The hydrogen ion index of each tire puncture sealant obtained was measured with a pH meter (manufactured by Hitachi High-Technology Corporation). For each tire puncture sealant, the following methods were used to evaluate rust prevention, odor, freezing point, sealability, thermal cycle stability, shake test, storage stability, liquid supply property, and air supply property. .
The results are shown in Table 1.

(Rust prevention)
Each tire puncture sealant was applied to the surface of a steel sheet degreased with methyl ethyl ketone, allowed to dry at 20 ° C. for 24 hours, and then left in warm water at 50 ° C. for 7 days. Thereafter, the sealing material was peeled off from the steel sheet, and the surface of the steel sheet was visually observed to evaluate the presence or absence of rust.
The case where rust did not occur was indicated as “◯”, and the case where rust occurred was indicated as “x”.

(Odor)
Each tire puncture sealant was checked for odor.
“O” indicates no odor and “X” indicates a strong odor.

(Freezing point)
The freezing point was measured using a differential scanning calorimeter (DSC, manufactured by TA Instruments).

(Sealability)
A hole was formed by penetrating a nail having a diameter of 5 mm through a tread of a member obtained by cutting the tire tread portion into a length of 15 cm and a width of 22 cm.
Assuming that the inside of the tire was injected in a 20 ° C., 65% RH environment, 50 g of each tire puncture sealant was hung from the back side (inside) of the tread to the hole portion.
In order to promote film formation, the periphery of the hole portion was hit with a mallet five times from the tread side.
After leaving for 20 minutes in an environment of 20 ° C. and 65% RH, water was sprayed from the tread side to the hole portion, and the presence or absence of water leakage to the back surface (inside) was observed.
The case where there was no water leak was indicated as “◯”, and the case where there was a water leak was indicated as “x”.

(Cool cycle stability)
Each tire puncture sealant was cooled at −20 ° C. for 8 hours and then heated at 80 ° C. for 16 hours. After repeating this cycle 10 times, the dispersion state was visually observed, and there was no precipitation and the particles were uniformly dispersed. “◯” was used for the sample, and “Δ” was used for the case where the aggregate or film was present.

(Shaking test)
In a 70 ° C. atmosphere, the glass bottle containing 200 g of the sealing material was sealed and shaken at 1 to 5 Hz for 60 hours.
Thereafter, the dispersion state was visually observed, and “◯” indicates that there was no precipitation / separation, and “Δ” indicates that there was an aggregate or film.

(Storage stability)
The obtained tire puncture sealant was put in a container, purged with nitrogen, sealed, and left at 80 ° C. for 100 days. Thereafter, the state of the tire puncture sealant was observed, the dispersion state was visually observed, and “◯” indicates that there was no precipitation / separation, and “Δ” indicates that there was an aggregate or film.

(Liquid feeding property)
A compressor having a power source (12 V) obtained from a cigar lighter was attached to a plastic container containing 500 ml of the obtained tire puncture sealant, and a nozzle was attached to a tire valve. Next, the sealing material was fed into the tire at 0.5 MPa pressure and normal temperature, and the time (seconds) required to feed all the sealing material in the plastic container into the tire was measured.

(Air supply)
After the liquid feeding test, air was continuously introduced at room temperature, and the time (seconds) required until the compressor pressure gauge reached 0.3 MPa was measured.

The components shown in Table 1 are as follows.
Polyethylene emulsion 1: Nopcoat PEM-17, manufactured by San Nopco, solid content 40% by mass, pH 7.0
-Polyethylene emulsion 2: PE401, manufactured by Naruse Chemical Co., Ltd., solid content 60% by mass, pH 7.0
Polypropylene emulsion: PP emulsion, manufactured by Maruyoshi Kasei Co., Ltd., solid content 50% by mass, pH 7.0
Polybutene emulsion 1: Emmawet 10E, manufactured by NOF Corporation, solid content 53% by mass, pH 7.0
Polybutene emulsion 2: Emmawet 30E, manufactured by NOF Corporation, solid content 53% by mass, pH 7.0
・ Natural rubber latex: HA, manufactured by Felfex, solid content 60% by mass, pH 11.5
-Tackifier: Harrier Star SK508, Harima Kasei Co., Ltd., solid content 54% by mass, pH 6.5
-Antifreeze agent (ethylene glycol): Wako Pure Chemical Industries, solid content 100% by mass
・ Hydrochloric acid: Wako Pure Chemical Industries, Ltd. ・ Triethylamine: Wako Pure Chemical Industries, Ltd.

As is clear from the results shown in Table 1, the natural rubber latex tire puncture seal material (Comparative Example 1) had a high pH, rust, an irritating odor, and low storage stability. Further, the NBR tire puncture sealant (Comparative Example 2) had a high pH, rust was generated, there was an irritating odor, and liquid feeding properties and air feeding properties were low.
On the other hand, Examples 1-32 had the sealing performance equivalent to Comparative Examples 1-2, and was excellent in storage stability, liquid feeding property, and air feeding property. Furthermore, there was no rust and it was odorless.

Claims (8)

  A tire puncture sealant containing a polyolefin emulsion and an antifreezing agent.   2. The tire puncture sealing material according to claim 1, wherein the polyolefin emulsion is at least one emulsion selected from the group consisting of a polyethylene emulsion, a polypropylene emulsion, an ethylene-propylene copolymer emulsion, and a polybutene emulsion.   The tire puncture sealant according to claim 1 or 2, comprising 90 to 500 parts by mass of the antifreezing agent with respect to 100 parts by mass of the solid content of the polyolefin emulsion.   Furthermore, the tire puncture sealing material in any one of Claims 1-3 containing a tackifier.   The tire puncture sealant according to claim 4, wherein the tackifier is an emulsion obtained by emulsifying a resin.   The tire puncture sealant according to claim 4 or 5, wherein the tackifier includes at least one selected from the group consisting of a rosin resin, a terpene resin, and a hydrogenated terpene resin.   The tire puncture sealant according to any one of claims 4 to 6, wherein the solid content of the tackifier is 50 to 250 parts by mass with respect to 100 parts by mass of the solid content of the polyolefin emulsion.   The tire puncture seal material according to any one of claims 1 to 7, which has a hydrogen ion index of 5.5 to 8.5.