JP6435808B2 - Tire puncture sealant - Google Patents

Description

  The present invention relates to a tire puncture seal material.

Conventionally, tire puncture seal materials have been used to repair tire punctures as soon as possible.
The present applicant has so far provided a tire puncture sealant containing natural rubber latex and a surfactant, wherein the surfactant is added in an amount of 1.0 to 6.0% by mass based on the solid content of the natural rubber latex. And the surfactant contains a nonionic surfactant and an anionic surfactant. Nonionic surfactant / anionic surfactant = 1.0 / 1.0 to 1.0 / 5 A tire puncture sealant containing 0.0 mass ratio was proposed (Patent Document 1). Patent Document 1 describes that the nonionic surfactant has an HLB value of 12.0 to 19.0% (Claim 2). In the examples, the nonionic surfactant has an HLB value of 12.1%. Is used.

JP 2011-26544 A

However, if the tire puncture sealant containing natural rubber latex is stored for a long period of time, the solid content of the natural rubber latex will float, resulting in a difference in viscosity between the upper and lower parts of the tire puncture sealant. The present inventor has found that there is a problem that a cream-like layer is formed near the surface of the tire puncture sealant and a water layer is present under the layer. When the cream is generated, it is necessary to shake the tire puncture sealing material in advance before using the tire puncture sealing material in order to ensure the sealing performance of the tire puncture sealing material.
In addition, the conventional tire puncture sealant containing natural rubber latex and a nonionic surfactant may cause coagulation in the tire puncture sealant after long-term storage, The inventor has found that this can occur.
Then, this invention makes it a subject to provide the tire puncture sealing material which can suppress generation | occurrence | production of a solidified substance and cream.

As a result of earnest research to solve the above problems, the present inventor,
Including natural rubber latex, nonionic surfactant, and organic acid,
The nonionic surfactant has an HLB value of 14 to 19,
According to the present invention, it is found that the organic acid content is 1 to 20 parts by mass with respect to 100 parts by mass of the solid content of the natural rubber latex. It came.
The present invention is based on the above knowledge and the like, and specifically, solves the above problems by the following configuration.

1. Including natural rubber latex, nonionic surfactant, and organic acid,
The nonionic surfactant has an HLB value of 14 to 19,
A tire puncture sealant in which the content of the organic acid is 1 to 20 parts by mass with respect to 100 parts by mass of the solid content of the natural rubber latex.
2. 2. The tire puncture sealing material according to 1, wherein the organic acid is at least one selected from the group consisting of acetic acid and oxalic acid.
3. The tire puncture seal material according to 1 or 2 above, wherein the hydrogen ion index is 5.0 to 8.5.
4). The tire puncture sealant according to any one of 1 to 3, further comprising an ethylene-vinyl acetate-vinyl versatate resin emulsion.

  The tire puncture sealant of the present invention can suppress the generation of coagulum and cream.

Hereinafter, the present invention will be described in detail.
The tire puncture seal material of the present invention is
Including natural rubber latex, nonionic surfactant, and organic acid,
The nonionic surfactant has an HLB value of 14 to 19,
It is a tire puncture sealing material whose content of the said organic acid is 1-20 mass parts with respect to 100 mass parts of solid content of the said natural rubber latex.

In the present specification, the natural rubber latex contains at least water as a dispersion medium and contains at least natural rubber particles as a dispersoid. The solid content of the natural rubber latex contains at least natural rubber. Solid content contains at least the component which seals the puncture of a tire. The solid content of the natural rubber latex can be obtained by removing water from the natural rubber latex. However, the solid content does not include inorganic substances. The same applies to the emulsion and the solid content of the emulsion.
Moreover, the numerical range represented using “to” means a range including numerical values described before and after “to” as the lower limit value and the upper limit value.
When a component contains 2 or more types of compounds, content of the said component refers to content of the sum total of 2 or more types of compounds.

Since the tire puncture sealant of the present invention has the above-described configuration, it is considered that a desired effect can be obtained. The reason is not clear, but it is presumed that it is as follows.
The phenomenon that the above-mentioned cream is generated in the tire puncture sealant is that the specific gravity of the natural rubber particles in the natural rubber latex used in the tire puncture sealant is around 0.9 and the interface of the natural rubber particles. The present inventor thought that the cause is that protein and ammonia are adsorbed.
On the other hand, in the present invention, a nonionic surfactant having an HLB value in a specific range is adsorbed on the interface of the natural rubber particles, and the specific acid neutralizes ammonia in the natural rubber particles. Even after long-term storage, the inventors infer that the difference in viscosity between the upper part and the lower part of the tire puncture sealant is eliminated or the difference is reduced, and the generation of cream can be suppressed.
Further, the present inventor presumes that the natural rubber latex is stabilized by the adsorption and neutralization, and the generation of a solidified substance in the tire puncture sealant can be suppressed even after long-term storage.
Hereinafter, each component contained in the tire puncture sealant of the present invention will be described in detail.

[Natural rubber latex]
The natural rubber latex contained in the tire puncture seal material of the present invention is not particularly limited. Examples thereof include natural rubber latex to which protein is adsorbed and deproteinized natural rubber latex. The natural rubber latex may contain ammonia.
In the present invention, the solid content of the natural rubber latex is preferably 10 to 30% by mass in the total amount of the tire puncture sealant.

[Nonionic surfactant]
The nonionic surfactant contained in the tire puncture seal material of the present invention has an HLB value of 14 to 19. When the HLB value is less than 14, a solidified product and a cream may be generated in the tire puncture sealant after storage, resulting in poor storage performance.

The HLB value of the nonionic surfactant is excellent in a predetermined effect, preferably 14.5 to 18.5, and more preferably 16.5 to 18.0.
In the present invention, the HLB (Hydrophile-Lipophile Balance) value is defined by the Griffin method.

The nonionic surfactant is not particularly limited with respect to its structure. Examples thereof include polyoxyethylene alkyl ethers; sulfates such as alkyl sulfates and polyoxyethylene alkyl ether sulfates.
The cation forming the sulfate is not particularly limited. An example is sodium.

Examples of the polyoxyethylene alkyl ether include polyoxyethylene decyl ether, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene 2-ethylhexyl ether, polyoxyethylene isodecyl ether, polyoxyethylene Examples thereof include oxyethylene tridecyl ether and polyoxyethylene isostearyl ether.
Examples of the polyoxyethylene alkyl ether sulfate salts include the sulfate salts of the above polyoxyethylene alkyl ethers.

Examples of the alkyl sulfate ester salt include sodium lauryl sulfate, triethanolamine lauryl sulfate, and ammonium lauryl sulfate.
The nonionic surfactants can be used alone or in combination of two or more.

  The content of the nonionic surfactant is 1 to 15 parts by mass with respect to 100 parts by mass of the solid content of the natural rubber latex from the viewpoint that it is excellent by a predetermined effect and excellent in suppressing aggregation of natural rubber particles. Is preferable, and it is more preferable that it is 5-10 mass parts.

[Organic acid]
The organic acid contained in the tire puncture sealant of the present invention is not particularly limited as long as it is an acid containing a carbon atom. The organic acid can have, for example, an acid group such as a carboxy group (—COOH), a sulfo group, or a group containing a phosphorus atom. Of these, compounds having a carboxy group are preferred.
The acid group can be bonded to a hydrogen atom or a hydrocarbon group. The hydrocarbon group is not particularly limited. For example, an aliphatic hydrocarbon group (which may be linear, branched or cyclic), an aromatic hydrocarbon group, or a combination thereof may be mentioned. The hydrocarbon group may have an unsaturated bond.

Examples of the organic acid include monocarboxylic acids such as formic acid, acetic acid, propionic acid, octanoic acid, stearic acid, (meth) acrylic acid, and benzoic acid; oxalic acid, malonic acid, succinic acid, sebacic acid, maleic acid, Examples thereof include dicarboxylic acids such as phthalic acid; trifunctional or higher functional carboxylic acids such as citric acid.
Of these, a monocarboxylic acid is preferable from the viewpoint of being excellent in a predetermined effect. Further, from the viewpoint of being superior in a predetermined effect, saturated fatty acids such as acetic acid, propionic acid, octanoic acid and stearic acid are preferable.
In addition, the organic acid is preferably at least one selected from the group consisting of acetic acid and oxalic acid from the viewpoint of being excellent in a predetermined effect and easy to handle.
The organic acids can be used alone or in combination of two or more.

Content of organic acid is 1-20 mass parts with respect to 100 mass parts of solid content of natural rubber latex.
The content of the organic acid is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the solid content of the natural rubber latex, from the viewpoint of being excellent by a predetermined effect and excellent in suppressing aggregation between natural rubber particles. It is more preferably 1 to 5 parts by mass.

[Synthetic resin emulsion]
The tire puncture sealant of the present invention can further contain a synthetic resin emulsion. The synthetic resin emulsion is not particularly limited. Examples thereof include an ethylene-vinyl acetate copolymer resin (hereinafter sometimes referred to as “EVA”) emulsion, and specifically, for example, an ethylene-vinyl acetate-vinyl versatate resin emulsion, an ethylene-vinyl acetate- (meth). An acrylic acid ester copolymer resin emulsion is mentioned.

In the present invention, the ethylene-vinyl acetate copolymer resin contained as a dispersoid in the ethylene-vinyl acetate copolymer resin emulsion means a copolymer resin containing at least ethylene and vinyl acetate as monomer units. That is, the ethylene-vinyl acetate copolymer resin is not particularly limited as long as it is a copolymer resin containing ethylene and vinyl acetate as monomer units.
The ethylene-vinyl acetate copolymer resin may further contain, for example, versatic acid vinyl ester (veova) and (meth) acrylic acid ester as monomer units in addition to ethylene and vinyl acetate.
Examples of the ethylene-vinyl acetate copolymer resins having a monomer unit other than ethylene and vinyl acetate include ethylene-vinyl acetate-vinyl versatate resins, ethylene-vinyl acetate- (meth) acrylates, and the like. A polymerization resin is mentioned.
Of these, ethylene-vinyl acetate-vinyl versatate resin is preferable.
The synthetic resin emulsions can be used alone or in combination of two or more.

  The content of the solid content of the synthetic resin emulsion is preferably 10 to 50 parts by mass and more preferably 10 to 30 parts by mass with respect to 100 parts by mass of the solid content of the natural rubber latex.

From the viewpoint that the tire puncture sealant can prevent the tire puncture sealant from freezing, the tire puncture sealant further includes an antifreezing agent.
The antifreezing agent is not particularly limited. For example, it is preferably at least one selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, glycerin and 1,3-propanediol.
Antifreeze agents can be used alone or in combination of two or more.

  The content of the antifreezing agent is preferably 50 to 200 parts by mass and more preferably 100 to 200 parts by mass with respect to 100 parts by mass of the natural rubber latex.

The hydrogen ion index of the tire puncture sealant of the present invention is preferably 5.0 to 8.5, more preferably 5.0 to 7.0, from the viewpoint that it is more excellent due to a predetermined effect.
In the present invention, the hydrogen ion index of the tire puncture sealant was measured under a condition of 23 ° C. using a pH meter.

  In addition to the components described above, the tire puncture seal material of the present invention includes, for example, a surfactant other than a predetermined nonionic surfactant, a filler, an anti-aging agent, an antioxidant, a pigment (dye), a plasticizer, It can contain additives such as thixotropic agents, ultraviolet absorbers, flame retardants, dispersants, dehydrating agents, antistatic agents and the like.

  The production of the tire puncture seal material of the present invention is not particularly limited. For example, a natural rubber latex, a predetermined nonionic surfactant, an organic acid, a synthetic resin emulsion, an antifreezing agent, an additive, water, etc. that can be used as necessary are placed in a container, and a mixing mixer under reduced pressure. The method of mixing and manufacturing using a stirrer is mentioned.

  The viscosity of the tire puncture sealant of the present invention is preferably 30 to 40 mPa · s. In the present invention, the tire puncture sealant has a viscosity of BL type viscometer, rotor No. 2 was measured under an atmosphere of 20 ° C.

The tire puncture seal material of the present invention is not particularly limited with respect to its usage. For example, a conventionally well-known thing is mentioned.
The tire puncture seal material of the present invention can be used, for example, as a hand-drawn tire emergency puncture repair liquid.

  Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to these.

<Manufacture of tire puncture seals>
Each component shown in Table 1 was used in the composition (parts by mass) shown in the same table, and they were mixed uniformly to produce each tire puncture seal material.
Regarding the amount of the natural rubber latex, the upper part is the amount of the whole natural rubber latex, and the lower part is the amount of the solid content of the natural rubber latex. The same applies to the VEVA emulsion.

<Evaluation>
The following evaluation was performed using the tire puncture seal material manufactured as described above. The results are shown in Table 1.
-Seal performance A puncture hole (diameter 4 mm) was formed in the shoulder groove portion of the tire tread.
Next, the tire with puncture holes was mounted on a drum testing machine, and each tire puncture seal material produced as described above was injected from the valve opening of the tire, and was filled with air so that the tire internal pressure was 200 kPa.
After that, intermittent operation (1 cycle per minute) was repeated by running the tire for 1 minute under the condition of 350 kg load and 30 km / h, and the presence of air leakage was confirmed by spraying soapy water near the puncture hole. Then, intermittent operation was performed until air leakage disappeared.
As a result, the case where air leakage disappeared after repeating the intermittent operation for 1 to 10 cycles was evaluated as “A” because the sealing performance was very excellent.
Those in which air leakage did not occur after intermittent operation was repeated 11 to 15 cycles were evaluated as “B” because the sealing performance was excellent.
Even if the intermittent operation was repeated for 16 cycles or more, the case where air leakage did not disappear was evaluated as “C” because the sealing performance was inferior.

-Storage performance Storage performance of putting 1000 g of each tire puncture sealant manufactured as described above into a container having a height of 25 cm, replacing the inside with a nitrogen gas and sealing it, and placing the container under a condition of 70 ° C for 168 hours. A test was conducted.

-Generation | occurence | production of solidified material The tire puncture sealing material after performing the storage performance test as mentioned above was filtered with 100 mesh.
When the tire puncture sealant was filtered and coagulum remained as a filtrate, it was evaluated as “present” as there was coagulum in the tire puncture sealant.
The case where no filter residue remained was evaluated as “none”, assuming that there was no coagulum in the tire puncture sealant.

・ Viscosity of tire puncture sealant Using the tire puncture sealant after the storage performance test as described above, the viscosity of the upper part of the tire puncture sealant and the viscosity of the lower part of the tire puncture sealant are determined as BL type viscosity. Measurement was performed using a meter (rotor No. 2) in an atmosphere at 20 ° C. (unit: mPa · s).
The upper part of the tire puncture sealant is a part at a depth of 4 to 6 cm from the surface of the tire puncture sealant. The lower part of the tire puncture sealant is a part at a height of 4 to 6 cm from the bottom surface of the container. Tire puncture sealing material was extracted from each part.
The closer the upper viscosity / lower viscosity is to 1, the more cream generation can be suppressed and the better the storage performance.

-Generation | occurrence | production of cream The tire puncture sealing material after performing the storage performance test as mentioned above was confirmed visually.
The case where cream occurred in the tire puncture sealant was evaluated as “Yes”.
The case where there was no cream in the tire puncture sealant was evaluated as “none”.

Details of each component shown in Table 1 are as follows.
・ Natural rubber latex: Hytex HA, manufactured by Nomura Trading Co., Ltd., solid content 60% by mass
-VEVA emulsion: ethylene-vinyl acetate-vinyl versatate copolymer resin emulsion (Sumikaflex 950HQ, manufactured by Sumika Chemtex Co., Ltd., ethylene: vinyl acetate: vinyl versatate = 10: 5: 85, solid content 53% by mass)
Comparative nonionic surfactant: polyoxyethylene lauryl ether (trade name Emulgen 108, manufactured by Kao Corporation, HLB = 12.1)
Nonionic surfactant 1: polyoxyethylene lauryl ether (trade name Emulgen 120, manufactured by Kao Corporation, HLB = 13.6)
Nonionic surfactant 2: polyoxyethylene lauryl ether (trade name Emulgen 123P, manufactured by Kao Corporation, HLB = 16.9)
Nonionic surfactant 3: polyoxyethylene lauryl ether (trade name Emulgen 130K, manufactured by Kao Corporation, HLB = 18.1)
-Organic acid 1: Acetic acid-Organic acid 2: Oxalic acid-Antifreezing agent: Propylene glycol (Reagent grade 1, Wako Pure Chemical Industries, Ltd.)

As is apparent from the results shown in Table 1, in Comparative Examples 1 and 2 not containing an organic acid, a cream was generated after the storage performance test.
In Comparative Example 3 containing no nonionic surfactant, a coagulated product was generated after the storage performance test.
In Comparative Example 4 containing a nonionic surfactant having an HLB value outside the predetermined range, a coagulum and a cream were generated after the storage performance test.

On the other hand, Examples 1-6 were able to suppress the generation of coagulum and cream.
Moreover, when Examples 1-3 were compared, it turned out that the ratio of the viscosity of the upper part with respect to the viscosity of the lower part of the tire puncture sealing material after a storage performance test becomes close to 1, so that the quantity of organic acid increases.
When Examples 2, 4, and 5 were compared with respect to the ratio of the upper viscosity to the lower viscosity of the tire puncture sealant after the storage performance test, the results of Examples 2 and 5 were closer to 1 than Example 4. Therefore, when the HLB value of a nonionic surfactant exceeds 13.6, it is thought that it is excellent by suppression of generation | occurrence | production of a coagulum and / or cream.
Comparing Example 2 and Example 6, in Example 2, the ratio of the upper viscosity to the lower viscosity of the tire puncture sealant after the storage performance test was closer to 1 than in Example 6. . Therefore, it is considered that a monocarboxylic acid is more excellent as an organic acid than dicarboxylic acid in suppressing the generation of a coagulum and / or cream.

Claims (4)

Including natural rubber latex, nonionic surfactant, and organic acid,
The nonionic surfactant has an HLB value of 14 to 19,
A tire puncture sealant in which the content of the organic acid is 1 to 20 parts by mass with respect to 100 parts by mass of the solid content of the natural rubber latex.   The tire puncture sealant according to claim 1, wherein the organic acid is at least one selected from the group consisting of acetic acid and oxalic acid.   The tire puncture sealant according to claim 1 or 2, having a hydrogen ion index of 5.0 to 8.5.   The tire puncture sealing material according to any one of claims 1 to 3, further comprising an ethylene-vinyl acetate-vinyl versatate resin emulsion.