JP2018086728A - Release agent for bladder internal addition and use thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a release agent for bladder internal addition excellent in repetition releasability with a raw tire in the step of molding and vulcanizing a tire; a bladder excellent in repetition releasability; and a method for manufacturing the tire using the release agent for bladder internal addition.SOLUTION: The release agent for bladder internal addition includes: at least one kind selected from the following component (A) and the following component (B); and the following component (C). A ratios [C/(A+B)] of the weight of the component (C) to the total weight of the at least one kind selected from the component (A) and the component (B) is 0.05-10. The component (A) is wax; the component (B) is metal soap; and the component (C) is polyhydric alcohol.SELECTED DRAWING: None

Description

  The present invention relates to a release agent for internal addition to a bladder. More specifically, the present invention relates to a bladder-added mold release agent that exerts lubrication and mold release action with a tire by being internally added to a bladder rubber used during tire vulcanization molding.

  When molding and vulcanizing a tire, the bladder is inserted into the raw tire before molding and vulcanized, the bladder is expanded, the raw tire is pressed against a mold and heated and pressurized to perform molding and vulcanization. In this case, since both the bladder and the tire inner surface are made of rubber, releasability is required between them.

Conventionally, for molding vulcanization of tires, a method of applying a release agent called inside paint to the inner surface of the green tire each time, or a silicone-based on the surface of the bladder to improve the peeling between the green tire and the bladder. A method of applying a release agent has been performed.
Patent Document 1 proposes a powder release agent composition comprising a polymer of dialkylpolysiloxane and polyalkylene glycol and mica or talc. However, the method of applying the inside paint to the inner surface of the green tire each time has a problem that the process becomes complicated and stains around the device occur during application.
Therefore, as a method different from the inside paint, there is a method of coating a release agent on the bladder surface.
Patent Document 2 proposes a method using a vulcanizing bladder surface-treated with a silicone composition containing an organopolysiloxane, methylhydrogensiloxane, silica and a metal organic acid salt. However, since the adhesion between the release agent film and the bladder is insufficient, the mold release property at the time of the molding vulcanization process is weak, and when continuously molding and vulcanizing, the mold release film deteriorates in a short time, It is necessary to apply the release agent 10 times or more until the life of the bladder is exhausted. In addition, there are disadvantages in that the variation of workers is large, it is difficult to apply uniformly, and it is difficult to form a film having a stable thickness.
In order to omit the step of applying the release agent as described above, a method of internally adding the release agent at the time of producing the bladder is also considered.
For example, Patent Document 3 proposes a method of internally adding a fluorine-based resin to rubber constituting a bladder. However, since the fluororesin powder is only dispersed in the rubber, the releasability is not sufficient. Further, when the blending amount of the fluororesin is increased, there is a problem that the rubber physical properties of the bladder are adversely affected and the life of the bladder is shortened.

JP 52-86477 A JP-A-62-275711 JP 9-234744 A

  A release agent for internal addition of a bladder excellent in releasability with a raw tire during a molding vulcanization process of a tire, a bladder excellent in releasability of release, and a tire using the release agent for internal addition of a bladder And a manufacturing method.

As a result of intensive studies to solve the above problems, the present inventors have solved the above problems by using a mold release agent for internal addition of a bladder containing at least one of two specific components and a polyhydric alcohol component. As a result, the present invention has been reached.
That is, the release agent for internal addition of the bladder of the present invention contains at least one selected from the following component (A) and the following component (B), and the following component (C).
Ingredient (A): Wax Ingredient (B): Metal soap Ingredient (C): Polyhydric alcohol

The component (A) and the component (B) are preferably solid at 20 ° C., and the component (C) preferably has a viscosity of 100 mPa · s or higher at 20 ° C.
The component (A) preferably contains paraffin wax, and the component (B) preferably contains a non-alkali metal salt of an organic acid having 10 to 18 carbon atoms.
The component (C) preferably contains at least one selected from glycerin and polyglycerin.

  The bladder of the present invention includes a rubber component and the above-mentioned release agent for internal addition of the bladder.

  The total of at least one selected from the component (A) and the component (B) is 0.1 to 10 parts by weight, and the component (C) is 0.1 to 10 parts by weight with respect to 100 parts by weight of the rubber component. Part is preferred.

  The tire manufacturing method of the present invention includes a vulcanization step in which the bladder is heated and expanded to press-fit a raw tire into a mold and vulcanize and mold.

  The release agent for internal addition of the bladder of the present invention is excellent in repetitive release properties.

  First, each component mix | blended with the mold release agent for bladder internal addition of this invention is demonstrated.

[Component (A): Wax]
The mold release agent for internal addition of the bladder of this invention contains at least 1 sort (s) chosen from the wax which is a component (A), and the fatty acid soap which is the component (B) mentioned later.
This component (A) or component (B) plays the role of maintaining the releasability of the release agent for internal addition of the bladder, that is, excellent releasability even when tire molding is repeated.
As a factor that the component (A) or the component (B) is excellent in releasability, when it is internally added to the bladder, the bladder surface is coated over time by blooming on the bladder surface, and the bladder is subjected to tire molding vulcanization. It is presumed that the release property is exhibited by being interposed between the tire and the tire.
In addition, as a factor that the component (A) or the component (B) is repetitively excellent in releasability, an appropriate amount of the bladder surface is coated every time the tire is molded because the speed of blooming on the bladder surface over time is appropriate. Estimated to do.

The component (A) is not particularly limited as long as it is a wax, but includes, for example, petroleum waxes such as paraffin wax, microcrystalline wax, and petratam; synthetic waxes such as polyhydric alcohol fatty acid esters, polyethylene wax, and oxidized polyethylene; Animal and plant waxes such as carnauba wax, candelilla wax, beeswax, lanolin, rice wax, banana wax, sugarcane wax; mineral waxes such as montan wax, ozokerite, and ceresin. The wax may be used alone or in combination of two or more.
Of these, petroleum wax, synthetic wax, animal and plant wax, and mineral wax are preferable, and animal and plant wax, petroleum wax, and synthetic wax are more preferable, and animal and plant wax and petroleum wax from the viewpoint of releasability. Is particularly preferable, and paraffin wax is most preferable among petroleum waxes.

  It is preferable from a viewpoint of mold release property that a component (A) is solid at 20 degreeC. The term “solid” as used herein means a substance having no fluidity regardless of whether it is hard or soft.

[Component (B): Metal soap]
The metal soap which is a component (B) is a component which provides releasability repeatedly. The metal soap used in the present invention is preferably a non-alkali metal salt of an organic acid having 10 to 18 carbon atoms from the viewpoint of repeated releasability, and may contain one or more kinds.

  The organic acid constituting the metal soap is not particularly limited, and may be any one selected from capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, and arachidic acid. It may contain more than seeds.

  The non-alkali metal salt constituting the metal soap is not particularly limited, but Al, Ag, Ba, Ca, Ce, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Sn, It may be one kind selected from Th, Ti, and Zn, and may contain two or more kinds.

  Further, the average particle diameter of the metal soap is not particularly limited, but is preferably 0.1 to 200 μm, more preferably 0.1 to 100 μm in view of repeated releasability.

[Component (C): Polyhydric alcohol]
The component (C) used in the release agent for internal addition of the bladder of the present invention is a polyhydric alcohol, and is a component that is excellent in repetitive release properties when used in combination with the component (A) or the component (B). .
Although the reason is not clear, the coating form on the bladder surface when the component (A) or the component (B) blooms with time due to the component (C) is more likely to exhibit continuous releasability. Because it has a function to adjust to
The polyhydric alcohol is preferably liquid at 20 ° C., and the viscosity at 20 ° C. is preferably 100 mPa · s or more, and more preferably 500 mPa · s or more. A preferable upper limit of the viscosity is 100,000 mPa · s.

Examples of the dihydric alcohol (polyhydric alcohol having 2 hydroxyl groups) include polyethylene glycols such as diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol and hexaethylene glycol; dipropylene glycol, tripropylene glycol and tetrapropylene. Polypropylene glycols such as glycol, pentapropylene glycol and hexapropylene glycol; polybutylene glycols such as dibutylene glycol, tributylene glycol, tetrabutylene glycol, pentabylene glycol and hexabutylene glycol; ethylene glycol, 1,2-propylene glycol 1,3-propylene glycol, 1,2-butanediol, 1,4-butanediol, 1,2, Pentanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8-octane Diol, 1,2-octanediol, 1,9-nonanediol, 1,2-decanediol, 1,10-decanediol, 1,2-decanediol, 1,12-dodecanediol, 1,2-dodecanediol , 1,14-tetradecanediol, 1,2-tetradecanediol, 1,16-hexadecanediol, linear alkylene dihydric alcohols such as 1,2-hexadecanediol; 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol 2,4-dimethyl-2,4-dimethylpentanediol, 2,2-diethyl-1,3-propanediol, 2,2,4-trimethyl-1,3-pentanediol, dimethyloloctane, 2- Ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2, Branched alkylene dihydric alcohols such as 4-diethyl-1,5-pentanediol; 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cycloheptanediol, Examples thereof include cyclic alkylene dihydric alcohols such as tricyclodecane dimethanol.
Examples of the trihydric alcohol (polyhydric alcohol having 3 hydroxyl groups) include glycerin, trimethylolpropane, 1,2,6-hexanetriol, 3-methylpentane-1,3,5-triol, hydroxymethylhexanediol, A trimethylol octane etc. can be mentioned.

  Examples of the tetravalent or higher alcohol include pentaerythritol, sorbitol, polyglycerins and the like.

[Bladder internal release agent]
The release agent for internal addition of the bladder of the present invention comprises at least one selected from the above component (A) and the above component (B) and the above component (C).
The ratio [C / (A + B)] of the weight of the component (C) and the total weight of at least one selected from the component (A) and the component (B) is 0.05 to 10, .1-8 are preferred, 0.2-5 are more preferred, and 0.3-3 are even more preferred. If it is less than 0.05 and more than 10, the amount of the component (C) relative to the total amount of the component (A) and the component (B) is not an appropriate amount, and the effect of the present application cannot be exhibited.
The mold release agent for internal addition of the bladder of the present invention may contain additives such as a thickener, an antifoaming agent, and an antiseptic as necessary in addition to the components described above.
About the manufacturing method of the mold release agent for the bladder internal addition of this invention, if it includes the process of mixing the said component (A), the said component (B), and the said component (C), a mixing order and the mixing to use There are no particular limitations on the equipment.

  The mixing is not particularly limited, and can be performed using an apparatus having a very simple mechanism such as a container and a stirring blade. Moreover, you may use the powder mixer which can perform a general rocking | swiveling or stirring. Examples of the powder mixer include a powder mixer that can perform rocking stirring or stirring, such as a ribbon mixer and a vertical screw mixer. In recent years, super mixers (manufactured by Kawata Co., Ltd.), high-speed mixers (manufactured by Fukae Co., Ltd.), and Newgram Machines (Seishin Co., Ltd.), which are efficient and multifunctional powder mixers by combining stirring devices Product), SV mixer (manufactured by Shinko Environmental Solution Co., Ltd.), and the like. Other examples include dry crushers such as jaw crusher, gyratory crusher, cone crusher, roll crusher, impact crusher, hammer crusher, rod mill, ball mill, vibration rod mill, vibration ball mill, disk type mill, jet mill, cyclone mill, etc. May be used.

  Since the component (A), the component (B), and the component (C), which are release agents for internal addition of the bladder of the present invention, may not be able to maintain product stability after mixing, There is no need. The component (A), the component (B), and the component (C) may be added separately in the kneading step when manufacturing the bladder rubber.

[Bladder]
The bladder of the present invention includes a rubber component and the above-mentioned release agent for internal addition of the bladder. That is, the bladder of the present invention includes a rubber component, at least one selected from the component (A) and the component (B), and the component (C). In some cases, short fibers for reinforcement are included. Although the reinforcing short fibers are not particularly limited, it is preferable to use fibers such as polyvinyl alcohol, aromatic polyamide, nylon, polyester, polyethylene, and natural cellulose.
About the said component (A), the said component (B), and the said component (C), what was described by the mold release agent for bladder internal addition can be used.
The rubber component preferably contains 90 parts by mass or more of butyl rubber composed of butyl rubber (IIR) and / or halogenated butyl rubber.
As the halogenated butyl rubber, brominated butyl rubber (Br-IIR) and chlorinated butyl rubber (Cl-IIR) are preferable.

(Other ingredients)
The bladder of the present invention preferably contains a zinc compound, sulfur, oil, carbon black, a thiazole compound or the like in addition to the components (A) to (C).
Examples of the zinc compound include zinc oxide (ZnO) and zinc stearate.
S8 etc. can be mentioned as sulfur.
Examples of the oil include palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, and ricinoleic acid.
Examples of the carbon black include furnace carbon black such as SAF, ISAF, HAF, FEF, and GPF, acetylene black, and channel carbon black.

  Examples of the thiazole compounds include accelerator TT (tetramethylthiuram disulfide), dibenzothiazyl disulfide (MBTS), cyclohexylamine salt of mercaptobenzothiazole (CMBT), N-cyclohexyl-2-benzothiazolesulfenamide (CBS). ), N-oxydiethylene-2-benzothiazole sulfenamide (OBS), mercaptobenzothiazole (MBT), Nt-butyl-2-benzothiazole sulfenamide (TBBS) and the like, and these thiazole compounds Among these, accelerator TT (tetramethyl thiuram disulfide) and dibenzothiazyl disulfide are particularly preferable. These thiazole compounds may be used individually by 1 type, or may use 2 or more types together, and what is marketed conventionally can be utilized.

  There is no particular limitation on the shape of the bladder. The shape can include, for example, a sheet shape, a film shape, a hose shape, a tube shape, a sponge shape, a packing, a belt, etc., even if a groove for escaping air to the outside during vulcanization molding is engraved. Good.

[Tire manufacturing method]
The tire manufacturing method of the present invention first includes a bladder manufacturing process.
(Bladder manufacturing process)
The bladder manufacturing process
1) A blending step in which the above-mentioned release agent for adding bladder is added to a rubber component, and a zinc compound or the like and various compounding agents appropriately selected as necessary are blended. 2) Kneading step, 3) Heating step 4) Includes an extrusion process.
(Tire manufacturing method)
Combining necessary members such as bead wires and tire cords mainly with unvulcanized rubber, and bonding them together, a tire prototype called a raw tire is prepared.
The tire manufacturing method of the present invention may be a manufacturing method including a vulcanization process in which the bladder obtained in the above-described bladder manufacturing process is heated and expanded to press-fit a raw tire into a mold and vulcanize molding. The manufacturing method of the tire of the invention is a manufacturing method including a vulcanization step in which a bladder including the above-mentioned release agent for internal addition of bladder and / or the above-mentioned bladder is heated and expanded to press-fit a raw tire into a mold and vulcanize and mold. There may be.

Below, the Example and comparative example of a mold release agent for bladder internal addition are demonstrated concretely. The present invention is not limited to these examples.
First, a method for evaluating physical properties of a mold release agent for bladder internal addition will be described.
[Evaluation of releasability]
The bladder produced in the example and the unvulcanized rubber were superposed and press vulcanized for 20 minutes at 160 ° C. and 2 MPa. After vulcanization, the bladder was cooled to room temperature, and the peel resistance (N / mm) was measured at a speed of 100 mm / min using a tensile tester Tensilon (PT-200N type, Minebea Co., Ltd.). The evaluation criteria for releasability are as follows. ○ was accepted.
○: Peel resistance is less than 0.01 N / mm ×: Peel resistance is 0.01 N / mm or more

[Repeated releasability evaluation]
Vulcanization was repeated in the same manner as described above, and the number of times that the releasability was maintained was measured. The more times that vulcanization can be repeated, the better the releasability. The evaluation criteria for repeated releasability are as follows. ◎ and ○ were accepted.
A: Even if vulcanization molding is repeated 100 times or more, the releasability is good continuously.
○: Repeated molding vulcanization can be performed with good releasability between 30 times and less than 100 times.
X: Repeated molding vulcanization can be performed with good releasability for less than 30 times.

[Adjustment of bladder rubber composition]
The following components were mixed in a predetermined amount to prepare a bladder rubber composition. In general, since the raw tire surface is mainly composed of butyl rubber, this rubber composition was used as an unvulcanized rubber for evaluation of releasability.
Rubber component IIR rubber: 100 parts by weight Bladder rubber composition other than rubber component ZnO: 3 parts by weight S8: 2 parts by weight Stearic acid: 1 part by weight Oil furnace black: 50 parts by weight Accelerator TT (tetramethylthiuram disulfide): 1 part by weight Part

[Example 1]
A rubber composition obtained by blending 1 part by weight of calcium stearate and 1 part by weight of glycerin with 157 parts by weight of the above bladder rubber composition (rubber component: 100 parts by weight, other rubber composition: 57 parts by weight). Was prepared, and then vulcanized to obtain a bladder internally added with a release agent. Table 1 shows the results of evaluation of releasability and repetitive releasability using this bladder. Excellent releasability and releasability.

[Examples 2 to 21]
In Examples 2 to 21, a release agent-added bladder was obtained in the same manner as in Example 1 except that the release agent composition was changed as shown in Tables 1 and 2, and the physical properties and the like were also shown in Examples. Evaluation was performed in the same manner as in 1. The results are shown in Tables 1 and 2. They were excellent in releasability and releasability.

[Comparative Example 1]
A rubber composition obtained by blending 15 parts by weight of calcium stearate and 0.2 parts by weight of glycerin with 157 parts by weight of a bladder rubber composition (rubber component: 100 parts by weight, other rubber composition: 57 parts by weight). By preparing and vulcanizing, a bladder containing a release agent was obtained. Table 2 shows the results of evaluation of releasability and repeated releasability using this bladder.

[Comparative Examples 2 to 10]
In Comparative Examples 2 to 10, a release agent-added bladder was obtained in the same manner as in Comparative Example 1 except that the composition was changed as shown in Table 2, and the physical properties and the like were the same as in Comparative Example 1. Evaluated. The results are shown in Table 3.

As can be seen from Tables 1 to 3, the release agent for internal addition of Examples 1 to 21 includes at least one selected from the component (A) and the component (B), and the component (C). A release agent for internal addition of bladder, wherein the ratio of the weight of the component (C) to the total weight of at least one selected from the component (A) and the component (B) [C / (A + B) ] Satisfies 0.05 to 10, it is excellent in releasability and repetitive mold release, which are the problems of the present application.
On the other hand, it contains one type selected from the component (A) and the component (B) and the component (C), but is selected from the weight of the component (C) and the component (A) and the component (B). When the ratio [C / (A + B)] to the total weight of at least one kind is not in the range of 0.05 to 10 (Comparative Examples 1 to 3, 7 and 8), the polyhydric alcohol (C) is not contained ( In Comparative Examples 2 and 3), when neither component (A) nor component (B) is contained (Comparative Examples 4 to 6, 9 and 10), any of the problems of the present application cannot be solved.

Claims (7)

A release agent for internal addition to a bladder comprising at least one selected from the following component (A) and the following component (B), and the following component (C), wherein the weight of the component (C), A mold release agent for internal addition to a bladder, wherein the ratio [C / (A + B)] to the total weight of at least one selected from A) and the component (B) is 0.05-10.
Ingredient (A): Wax Ingredient (B): Metal soap Ingredient (C): Polyhydric alcohol   The mold release agent for bladder internal addition according to claim 1, wherein the component (A) and the component (B) are solid at 20 ° C, and the component (C) has a viscosity of 100 mPa · s or more at 20 ° C.   The mold release agent for bladder internal addition of Claim 1 or 2 in which the said component (A) contains paraffin wax and the said component (B) contains the non-alkali metal salt of a C10-C18 organic acid.   The mold release agent for bladder internal addition in any one of Claims 1-3 in which the said component (C) contains at least 1 sort (s) chosen from glycerol and polyglycerol.   A bladder comprising a rubber component and a release agent for adding bladder internally according to any one of claims 1 to 4.   The total of at least one selected from the component (A) and the component (B) is 0.1 to 10 parts by weight, and the component (C) is 0.1 to 10 parts by weight with respect to 100 parts by weight of the rubber component. The bladder according to claim 5, which is a part.   A tire manufacturing method comprising a vulcanization step in which the bladder according to claim 5 or 6 is heated and expanded to press-fit a raw tire into a mold and vulcanize and mold.