JP2000272022A - Sealing agent for tire puncture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the solidification of natural rubber latex effectively in a valve with the generation of stimulant odors controlled and without lowering sealing performance below a necessary standard level by using a surfactant of a fatty acid salt of 9-18C and/or an acrylic emulsion as a stabilizer for the natural rubber latex. SOLUTION: Into a mixed liquid in which a terpene resin as a tackifier and ethylene glycol as an antifreezing agent are added into natural rubber latex, a fatty acid salt of 9-18C and/or an acrylic emulsion are added as a stabilizer for the latex. In this process, 1.0-7.0 wt.% based on the solid content of the latex of the stabilizer is added.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a puncture treatment system in which a puncture sealant and air are sequentially injected into a tire from an air bubble of a tire wheel when the tire is punctured. The present invention relates to a puncture sealing agent for a tire that does not cause bleeding and can exhibit sufficient sealing performance.

[0002]

2. Description of the Related Art As a treatment system for urgently repairing a punctured tire, a pressure-resistant container containing a sealing agent and a high-pressure air source such as a compressor are used, and a sealing agent is injected into the tire from an air valve. It is known that a tire is pumped up to a running air pressure.

[0003] The performance required of a sealing agent used in such a puncture treatment system is that the sealing agent can be smoothly injected into the tire; Hardened by mechanical stimulus due to tire deformation,
Closes puncture holes (initial sealing performance); ・ Maintains sealing performance up to a certain distance (seal retention performance); etc. Other than these, non-toxic, non-flammable, biodegradable, etc. Consideration must also be given to user protection and environmental protection.

[0004] From such performance requirements, a sealing agent containing natural rubber latex as a main component has been proposed.

[0005]

On the other hand, in the puncturing system, after the sealant has passed through the valve core, residual liquid of the sealant adheres to the valve core or the injection hose. When air is injected in this state, the residual liquid in the valve core is mechanically stimulated by the flow of the air, so that the residual liquid is easily coagulated. Once coagulation occurs, the resistance of the valve during air injection increases, causing an excessive pressure load on the injection hose and the entire system, and in some cases, completely shutting off the air injection.

Therefore, conventionally, a technique of improving the stability of the sealing agent by increasing the content of ammonia with respect to the natural rubber latex has been adopted. By this method, it can be confirmed that the coagulation of the residual liquid at the valve is in a direction to be suppressed. However, the amount of ammonia required to solve this problem is 1.2
% By weight (ratio to the solid content of the rubber latex), which significantly deteriorates the irritating odor of the sealing agent and, at the same time, lowers the sealing performance.

Accordingly, the present invention is based on the use of a fatty acid salt having 9 to 18 carbon atoms among surfactants and / or an acrylic emulsion as a stabilizer for natural rubber latex, instead of ammonia. An object of the present invention is to provide a tire puncture sealant capable of preventing solidification of residual liquid in a valve without suppressing generation and lowering sealing performance below a required reference level.

[0008]

In order to achieve the above object, the invention of a tire puncture sealant according to claim 1 of the present application is to provide a natural rubber latex with a terpene resin as an adhesive and ethylene glycol as an antifreeze. Wherein a fatty acid salt having 9 to 18 carbon atoms of a surfactant and / or an acrylic emulsion is added as a stabilizer for stabilizing the natural rubber latex.

Further, in the invention of claim 2, the stabilizer is
A fatty acid salt having 9 to 18 carbon atoms, wherein the content relative to the solid content of the natural rubber latex is 1.0 to 7.0% by weight.
It is characterized by having.

[0010] In the invention of claim 3, the stabilizer is
An acrylic emulsion, wherein the content of the natural rubber latex with respect to the solid content is 1.0 to 10.0% by weight.
It is characterized by having.

[0011] Further, the invention of claim 4 is characterized in that the solid content of the natural rubber latex is 25% by weight or more based on the total weight of the puncture sealing agent.

Further, in the invention according to claim 5, the natural rubber latex is a deproteinized rubber latex having a nitrogen content of 0.1% by weight or less based on the solid content of the natural rubber latex.

Further, the invention according to claim 6 is characterized in that the content of the ethylene glycol is 18 to 32% by weight based on the total weight of the puncture sealing agent.

In the invention of claim 7, the carbon number of 9 to
The surfactant comprising the fatty acid salt of No. 18 is ammonium laurate.

Further, the invention according to claim 8 is characterized in that the acrylic emulsion is an emulsion of 2-ethylhexyl acrylate / butyl acrylate / acrylic acid copolymer.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. The puncture sealing agent of the present invention is a natural rubber latex to which a terpene resin as an adhesive and ethylene glycol as an antifreezing agent are added, and a stabilizer for stabilizing the natural rubber latex is added. I have. As the stabilizer, a fatty acid salt having 9 to 18 carbon atoms among surfactants and / or an acrylic emulsion is used.

As the adhesive and the antifreezing agent, a terpene resin and ethylene glycol are used as in the prior art.

Here, as an additive for improving the stability of the puncture sealant while suppressing the deterioration of the sealing performance,
There are surfactants such as nonionic surfactants, amphoteric surfactants, and special carboxylic acid type surfactants.

However, as a result of our research,
For the solidification of the puncture sealant in the valve core,
It has been found that not all of these surfactants are effective and are limited to only a few, and in some cases, conversely, promote coagulation. That is, among the surfactants, it was possible to find out that particularly fatty acid salts having 9 to 18 carbon atoms can suppress coagulation in the valve without lowering the sealing performance.

Examples of the fatty acid in the fatty acid salt having 9 to 18 carbon atoms include capric acid having 10 carbon atoms, lauric acid having 12 carbon atoms, myristic acid having 14 carbon atoms, palmitic acid having 16 carbon atoms, and 18 carbon atoms. , Stearic acid, oleic acid, linoleic acid, linolenic acid, and the like. On the other hand, as the salt, a sodium salt, a potassium salt, an ammonium salt, a triethanolamine salt and the like can be considered.

Among them, ammonium laurate and the like can be preferably employed because they can exert a sufficient coagulation suppressing effect and can improve the coagulation suppressing effect in proportion to the content thereof.

In order to sufficiently exhibit this coagulation inhibitory effect, the solid content of the natural rubber latex must be
It is necessary to add 1.0% by weight or more of the fatty acid salt.

However, if the amount of addition (content) is too large, the viscosity of the puncture sealant tends to increase, and considering the injection into a tire at a low temperature, excessive addition is not preferable. In particular, when a fatty acid salt having the above-mentioned ammonium salt is used, ammonia is required when the fatty acid salt is formed. Therefore, if the amount is excessively increased, a pungent odor also becomes a problem. Therefore, the content of the fatty acid salt, including the ammonium salt, is preferably 7.0% by weight or less, and more preferably 5.0% by weight or less based on the solid content of the natural rubber latex.

As a stabilizer, an acrylic emulsion has the same effect as the fatty acid salt. This acrylic emulsion is an emulsion of a polymer and a copolymer using an acrylic monomer such as acrylic acid, methacrylic acid, or an ester thereof. A soft material exhibiting elasticity is preferable.

Examples of such an acrylic emulsion include 2-ethylhexyl acrylate / butyl acrylate / acrylic acid copolymer, 2-ethylhexyl acrylate / propyl acrylate / acrylic acid copolymer, and 2-ethylhexyl acrylate / ethyl acrylate / acryl. Acid copolymers and the like.

On the other hand, in order to effectively exert the above-described coagulation suppressing effect, it is necessary to add an acrylic emulsion of 1.0% by weight or more based on the solid content of the natural rubber latex. However, in consideration of a decrease in the sealing property, it is preferable to suppress the addition to 10.0% by weight or less, preferably 8.0% by weight or less based on the solid content of the natural rubber latex.

Further, when the fatty acid salt and the acrylic emulsion are combined, a particularly excellent coagulation suppressing effect can be obtained. For example, ammonium laurate, a fatty acid salt having 9 to 18 carbon atoms, and a soft acrylic emulsion, 2-ethylhexyl acrylate / butyl acrylate / acrylic acid copolymer emulsion (Nicazole TS805 manufactured by Nippon Carbide Co., Ltd.) Combinations are highly effective.

Next, the puncture sealant quickly enters the puncture hole by running, closes the puncture hole (initial sealing performance), and maintains the sealability up to a certain traveling distance (seal retention performance). Preferably, the solid content of the natural rubber latex is at least 25% by weight based on the total weight of the puncture sealant. Note that the content is preferably not more than 60% by weight for smooth injection into the tire.

From the viewpoint of suppressing the irritating odor of ammonia,
It is desirable to use a deproteinized rubber latex that can maintain stability with less ammonia as a sealing agent. At this time, considering the storage stability of the liquid, it is preferable to use a deproteinized rubber latex having a nitrogen content of 1.0% by weight or less based on the solid content of the natural rubber latex. The nitrogen content is a value measured by the Kjeldahl method.

The operating temperature range of the puncture sealant is
Considering the above-mentioned -25 ° C. in consideration of cold regions, the content of ethylene glycol as an antifreezing agent is preferably 18% by weight or more based on the total weight of the puncture sealing agent. It has been found that when ethylene glycol is added in a certain amount or more, the puncture sealing agent tends to coagulate in the valve core. Therefore, the upper limit of the content of ethylene glycol is desirably 32% by weight or less based on the total weight of the puncture sealing agent.

[0031]

EXAMPLES A puncture sealant was produced on the basis of the use of Tables 1 and 2, and the coagulation property, puncture sealability, and degree of ammonia-irritating odor in each sample were tested. No. 2. In the table, the ammonia content and the nitrogen content are the contents based on the solid content of the natural rubber latex.

(1) Solidification: tire size 225/60
After using a non-punctured tire of R16 and injecting 500 ml of a puncture sealant from an air valve,
The tire was pressurized by filling with air. And the actual tire pressure (actual tie and internal pressure) 5 minutes after pressure increase
And the valve resistance, which is the difference between the pressure and the air supply pressure at the time of filling, was evaluated as the degree of internal solidification.

(2) Puncture sealability: tire size 18
A hole was made in a 5 / 65R14 tire with a nail having a diameter of 3.4 mm, and after the nail was pulled out, 500 ml of a puncture sealing agent was injected from an air valve, and the pressure of the air was increased to 200 kpa. Thereafter, evaluation was made based on the traveling distance until the puncture hole was closed by actual vehicle traveling.・ Car… Tested with a puncture tire on the left side of the rear wheel of 1500cc (FF model) -Running speed: 20 km / h.

(3) Degree of ammonia-stimulated odor: The smell of the puncture sealant was smelled, and the odor was evaluated.

[0035]

[Table 1]

[0036]

[Table 2]

As shown in the table, the puncture sealant of the embodiment can effectively suppress the solidification in the valve while maintaining the required sealing performance. Therefore, when pumping up the tire, it is possible to prevent problems such as applying an unnecessarily high pressure load to the hose and the entire system, and preventing the pump from being pumped up to an internal pressure capable of running. In addition, since the nitrogen content can be kept low, the pungent odor of ammonia can be improved.

[0038]

As described above, the present invention uses a fatty acid salt having 9 to 18 carbon atoms among surfactants and / or an acrylic emulsion as a stabilizer for natural rubber latex instead of ammonia. Further, it is possible to effectively prevent solidification of the natural rubber latex in the valve without suppressing the generation of irritating odor and without lowering the sealing performance below a required standard level.

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[Procedure amendment]

[Submission date] April 6, 1999 (1999.4.6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

Here, as an additive for improving the stability of the puncture sealant while suppressing the deterioration of the sealing performance,
Nonionic surface active agents, amphoteric surface active agents, surface active agents, such as special Cal Bonn acid type surfactant.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0029

[Correction method] Change

[Correction contents]

From the viewpoint of suppressing the irritating odor of ammonia,
It is desirable to use a deproteinized rubber latex that can maintain stability with less ammonia as a sealing agent. At this time, considering the storage stability of the liquid, it is preferable to use a deproteinized rubber latex having a nitrogen content of 0.1 % by weight or less based on the solid content of the natural rubber latex. The nitrogen content is a value measured by the Kjeldahl method.

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Claims (8)

[Claims] 1. A mixture of a natural rubber latex and a terpene resin as an adhesive and ethylene glycol as an antifreezing agent, wherein a carbonaceous surfactant is used as a stabilizer to stabilize the natural rubber latex. A puncture sealing agent for a tire, wherein a fatty acid salt of several 9 to 18 and / or an acrylic emulsion is added. 2. The method according to claim 1, wherein the stabilizer is a fatty acid salt having 9 to 18 carbon atoms, and the content of the natural rubber latex with respect to the solid content is 1.0 to 7.0% by weight. Item 7. A puncture sealing agent for a tire according to item 1. 3. The tire according to claim 1, wherein the stabilizer is an acrylic emulsion, and a content of the natural rubber latex with respect to a solid content is 1.0 to 10.0% by weight. Puncture sealant. 4. A puncture sealing agent for a tire according to claim 1, wherein the solid content of said natural rubber latex is not less than 25% by weight based on the total weight of the puncture sealing agent. 5. The natural rubber latex has a nitrogen content of 0.1% by weight based on the solid content of the natural rubber latex.
The tire puncture sealing agent according to claim 1, 2, 3 or 4, which is the following deproteinized rubber latex. 6. The puncture sealing agent for a tire according to claim 1, wherein the content of the ethylene glycol is 18 to 32% by weight based on the total weight of the puncture sealing agent. . 7. The method according to claim 1, wherein the fatty acid salt having 9 to 18 carbon atoms is ammonium laurate.
The puncture sealing agent for a tire according to 2, 4, 5 or 6. 8. The puncture sealing tire according to claim 1, wherein said acrylic emulsion is an emulsion of 2-ethylhexyl acrylate / butyl acrylate / acrylic acid copolymer. Agent.