JP2011161766A - Bladder for manufacturing tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bladder for manufacturing a tire with a long durable life suppressing necessity of application of a release agent when vulcanizing a tire, and causing no early interlayer peeling. <P>SOLUTION: The bladder 4 for manufacturing a tire consisting of a plurality of layers has an outermost layer 1 containing a silicone rubber composition, a butyl rubber layer 2 containing a butyl rubber composition, and an intermediate layer 3 containing the silicone rubber composition and a resin compound between the outermost layer 1 and butyl rubber layer 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a tire manufacturing bladder (hereinafter, also simply referred to as a “blader”), and more specifically, suppresses the necessity of applying a release agent during tire vulcanization, and does not cause early peeling between layers and is durable. The present invention relates to a long-life tire manufacturing bladder.

  In general, in a tire manufacturing process, a tire molding bladder used when assembling each component of a tire to mold a raw tire (unvulcanized tire) and a final product tire shape at the time of vulcanization are provided. In general, two types of bladders are used, which are the tire vulcanizing bladder used in the above.

  Of these, tire vulcanization bladders are conventionally produced by vulcanization under certain conditions of high temperature and pressure, and butyl rubber compounds are used to ensure heat resistance and elongation. (1) Raw tires It has the following features: (2) low air / steam permeability, (3) good steam deterioration resistance, and (4) excellent heat resistance.

  However, butyl rubber is used as an inner liner in the innermost layer of the tire because of its low air permeability. Therefore, the butyl rubber of the tire and the bladder are co-crosslinked during vulcanization, and the inner surface of the tire or the bladder side is used to release the mold In addition, it is necessary to apply a release agent called an inner surface liquid (see, for example, Patent Document 1). For this reason, an internal liquid coating line is required, and the tire vulcanization lead time has been lengthened. In addition, since the release agent contains silicone oil or the like, if it is mixed into the joint portion of the inner liner of the tire, there is a risk of causing an inner crack, which places a great burden on production management.

  Therefore, it is known to use a silicone rubber composition as a technique that does not require the application of a release agent. For example, in Patent Document 2, silicone rubber is applied to all or part of the bladder surface. A raw tire molding bladder is disclosed, and Patent Document 3 discloses a technique capable of reliably obtaining physical properties of silicone rubber. Patent Document 4 discloses a technique using a rubber composition having a low peel stress from a rubber product such as an organic rubber such as butyl rubber on the inside of a bladder for tire vulcanization and a silicone rubber composition on the outside.

JP-A-6-339927 (paragraph [0002] etc.) Japanese Patent Laid-Open No. 57-181842 (Claims etc.) JP 2007-2183 A (Claims etc.) JP-A-5-31724 ([0009], [0011], etc.)

  However, when the silicone rubber composition is used, there is a problem that the silicone rubber composition is hydrolyzed by the high temperature steam used for expanding the bladder during tire vulcanization. In addition, the vulcanization bladder consisting of a multi-layer structure of butyl rubber and silicone rubber has low need to apply a release agent, and has solved the problem of hydrolysis of silicone rubber by blocking steam with butyl rubber. , Bladders with longer durability life have been demanded due to low cost requirements.

  Accordingly, an object of the present invention is to solve the above-mentioned problems, suppress the necessity of applying a release agent during tire vulcanization, and prevent a tire from being peeled off at an early stage, and a tire manufacturing bladder having a long durability life. It is to provide.

  As a result of intensive studies to solve the above problems, the present inventor solved the above problems by having a specific intermediate layer between the layer containing the silicone rubber composition and the layer containing the butyl rubber composition. The present inventors have found that this can be done and have completed the present invention.

That is, the tire manufacturing bladder of the present invention is a tire manufacturing bladder composed of a plurality of layers, and has an outermost layer containing a silicone rubber composition and a butyl rubber layer containing a butyl rubber composition,
An intermediate layer containing a silicone rubber composition and a resin compound is provided between the outermost layer and the butyl rubber layer.

  In the tire manufacturing bladder of the present invention, the resin compound is preferably a phenolic resin or a formaldehyde resin, and the intermediate layer is 0.7 to 100 parts by mass of the silicone rubber composition. It is preferable to contain 16 parts by mass of the resin compound.

Furthermore, in the bladder for tire manufacture of the present invention, the silicone rubber composition is
(A) a linear diorganopolysiloxane containing an alkenyl group bonded to two or more silicon atoms in one molecule;
(B) Average composition formula (R ¹ ) _x H _y SiO _{(4-xy) / 2} (where R ¹ is a substituted or unsubstituted monovalent hydrocarbon group excluding an aliphatic unsaturated group, x and y are each a positive number satisfying 1 ≦ x ≦ 2.2, 0.002 ≦ y ≦ 1, and 1.002 ≦ x + y ≦ 3), and two or more in one molecule An organohydrogenpolysiloxane containing hydrogen atoms bonded to silicon atoms of
(C) dry silica having a specific surface area of 100 m ² / g or more,
(D) It is preferable to contain a vulcanizing agent, and the vulcanizing agent is preferably a platinum group metal catalyst or a peroxide crosslinking agent.

Furthermore, in the bladder for tire manufacture of the present invention, the silicone rubber composition has a vinyl group in the polymer of 1.0 mol% or less as the (A) diorganopolysiloxane, and a molecular weight of 60 to 1,200,000. Preferably, the silicone rubber composition contains 2.0 parts by mass or less of the (B) organohydrogenpolysiloxane with respect to 100 parts by mass of the (A) diorganopolysiloxane. Preferably, the (C) dry silica is high-strength silica having a specific surface area of 200 to 400 m ² / g, and the silicone rubber composition is based on 100 parts by mass of the (A) diorganopolysiloxane. It is preferable to contain 40-60 mass parts of said (C) dry silica.

In the tire manufacturing bladder according to the present invention, the butyl rubber composition preferably contains a butyl polymer having a molecular weight of 60 to 1,200,000 as butyl rubber, and the butyl rubber composition has 100 parts by mass of the butyl rubber. It is preferable to contain 10-60 mass parts carbon black. Furthermore, the butyl rubber composition contains zinc oxide and a formaldehyde resin,
When the content of the zinc oxide in the butyl rubber composition is X parts by mass, and the content of the formaldehyde resin is Y parts by mass,
X + Y = 3-10
0.3 ≦ X / (X + Y) ≦ 0.7
It is preferable to satisfy the relationship.

  Furthermore, in the tire manufacturing bladder of the present invention, the thickness of the intermediate layer is preferably 1 to 25% of the thickness of the entire tire manufacturing bladder.

  According to the present invention, it is possible to provide a tire manufacturing bladder that can suppress the necessity of applying a release agent at the time of tire vulcanization and has a long durability life without causing early peeling between layers. .

It is a figure showing the bladder for tire manufacture concerning one embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a view showing a tire manufacturing bladder according to an embodiment of the present invention. As shown in FIG. 1, the tire manufacturing bladder 4 of the present invention comprises a plurality of layers, and has an outermost layer 1 containing a silicone rubber composition and a butyl rubber layer 2 containing a butyl rubber composition. And an intermediate layer 3 containing a silicone rubber composition and a resin compound between the butyl rubber layer 2 and the butyl rubber layer 2. By including the silicone rubber composition in the outermost layer 1 in contact with the tire inner surface, it is possible to suppress the necessity of applying a release agent due to the release action of the silicone rubber composition. Silicone rubber is hydrolyzed by steam water, but by having the butyl rubber layer 2 containing the butyl rubber composition, the steam water can be blocked and the silicone rubber can be prevented from hydrolysis. Further, since the intermediate layer 3 includes a resin compound that chemically adsorbs with the butyl rubber composition of the butyl rubber layer 2, and a silicone rubber composition that chemically adsorbs with the silicone rubber composition of the outermost layer 1, the bladder during tire vulcanization Uniform deformation failure that occurs in the double bladder during expansion or vacuum contraction can be prevented. Furthermore, by adopting the configuration of the present invention, a highly durable bladder can be realized without causing tire vulcanization defects such as brad squirrels and air traps. In FIG. 1, the tire manufacturing bladder 4 having a three-layer structure is shown. However, if the outermost layer 1, the butyl rubber layer 2, and the intermediate layer 3 are provided, four or more layers may be used. The outermost layer 1 means the layer of the bladder 4 that is closest to the rubber product among the molding presses arranged in the order of the mold, the tire and other rubber products, and the bladder 4 from the outside. The inner layer means the layer of the bladder 4 farthest from the rubber product.

  In the present invention, the resin compound that can be used for the intermediate layer 3 is not limited as long as it can be used for an ordinary bladder for manufacturing a tire, but from the viewpoint of heat resistance, for example, a phenol resin, a formaldehyde resin, or the like is desirable. . Specific examples of such resin compounds include cresol / formaldehyde cocondensation resin, ethylphenol / formaldehyde cocondensation resin, butylphenol / formaldehyde cocondensation resin, octylphenol / formaldehyde cocondensation resin, butylphenol / octylphenol / formaldehyde cocondensation resin, and the like. It is done. These cocondensation resins may be used alone or in combination of two or more.

  In this invention, it is preferable that the intermediate | middle layer 3 contains a 0.7-16 mass part resin compound with respect to 100 mass parts of silicone rubber compositions. There exists a possibility that adhesiveness with the butyl rubber layer 2 may become weak that content of a resin compound is less than 0.7 mass part. On the other hand, if the content of the resin compound exceeds 16 parts by mass, resin aggregates may be formed and the adhesiveness with the outermost layer 1 may be weakened.

  Moreover, as a silicone rubber composition used in this invention, it is preferable to contain the following (A)-(D) component. A high-strength silicone rubber composition improves wear resistance and fatigue durability, and a more durable bladder can be realized. The silicone rubber composition of the outermost layer 1 and the silicone rubber composition of the intermediate layer 3 both have the following components (A) to (D) in order to improve the adhesion between the outermost layer 1 and the intermediate layer 3. It is preferable to have a similar composition, and it is particularly preferable that the composition is exactly the same because the cost is low.

  In the present invention, the linear diorganopolysiloxane containing an alkenyl group bonded to two or more silicon atoms in one molecule used as the base polymer of the component (A) is an ordinary liquid addition-curable silicone rubber composition. It is a known organopolysiloxane used as a main raw material (base polymer) in products.

Such an organopolysiloxane generally has an average composition formula (R ² ) _a SiO _{(4-a) / 2} (where R ² is usually substituted or non-substituted having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms. Represents a substituted monovalent hydrocarbon group, which is bonded to a silicon atom forming a siloxane structure in the molecule, and a is 1.9 to 2.4, particularly 1.95 to 2.05. 2 or more, preferably 2 to 10, more preferably 2 to 5 alkenyl groups bonded to silicon atoms, and GPC (gel permeation chromatography). Graphite) Basically linear diorganopolysiloxane having a polystyrene-reduced weight average molecular weight of preferably 600,000 to 1200,000, more preferably about 600,000 to 1,000,000. The

In the above composition formula, R ² is an alkyl group such as methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, hexyl, cyclohexyl, etc .; an alkenyl group such as vinyl, allyl, propenyl, isopropenyl, butenyl, etc .; phenyl, tolyl Aryl groups such as xylyl; aralkyl groups such as benzyl and phenylethyl; and halogen-substituted or cyano-substituted hydrocarbon groups such as chloromethyl, bromoethyl, 3,3,3-trifluoropropyl, cyanoethyl, and the like. Alternatively, the unsubstituted monovalent hydrocarbon group may be different or the same. Here, the alkenyl group is preferably a vinyl group, and the other hydrocarbon groups are preferably a methyl group, a phenyl group and a trifluoropropyl group, and in particular, a substituted or unsubstituted monovalent hydrocarbon other than an alkenyl group. It is preferable that 95-100 mol% is a methyl group among groups. The content of the alkenyl group, the total organic groups (i.e., substituted or unsubstituted monovalent hydrocarbon groups described above) in ^{R 2,} usually 0.0001 mol%, preferably 0.001 to 10 mol%, in particular It is 0.01-5 mol%, and it is especially preferable that vinyl group content is 0.10 mol% or less. An alkenyl group contained in two or more molecules in one molecule may be bonded to either a silicon atom at both ends of the molecular chain or a silicon atom in the middle of the molecular chain. However, from the viewpoint of physical properties of the cured silicone rubber, it is preferable that it contains at least alkenyl groups bonded to silicon atoms at both ends of the molecular chain.

This organopolysiloxane is a linear diorganosiloxane whose main chain is composed of repeating diorganosiloxane units (R ₂ SiO _2/2 units), and some RSiO _3/2 units and / Or a branched structure containing SiO _4/2 units is allowed, but usually the main chain consists of only diorganosiloxane units (R ₂ SiO _2/2 units), and both ends of the molecular chain are It is preferably a linear diorganopolysiloxane blocked with a triorganosiloxy group (R ₃ SiO _1/2 unit), for example, dimethylpolysiloxane blocked with a dimethylvinylsiloxy group blocked at both ends of a molecular chain, or both ends of a molecular chain. Dimethylvinylsiloxy group-blocked dimethylsiloxane-methylvinylsiloxane copolymer, both ends of molecular chain dimethylvinylsiloxy group-blocked Dimethylsiloxane-diphenylsiloxane copolymer, etc. both molecular terminals with trimethylsiloxy groups dimethylsiloxane-methylvinylsiloxane copolymer.

  The (A) component alkenyl group-containing organopolysiloxane is a single polymer having these molecular structures or a mixture of these polymers. The alkenyl group-containing organopolysiloxane (A) may be used alone or in combination of two or more. When two or more alkenyl group-containing organopolysiloxane components having different weight average molecular weights are used in combination, the value of the weight average molecular weight of the whole mixture obtained by combining and mixing these two or more components is within the above range. It is preferable to be within.

等が挙げられる。ここでＲは、上記の置換または非置換の１価炭化水素基と同じであり、またｎ、ｍは、個々の単一の分子については、それぞれ上記の重量平均分子量を与える正の整数であり、重合度に分布を持った混合物としての均一成分については、平均値として上記の重量平均分子量を与える範囲の正数である。 As a suitable example of the component (A),

Etc. Here, R is the same as the above-mentioned substituted or unsubstituted monovalent hydrocarbon group, and n and m are each a positive integer that gives the above-mentioned weight average molecular weight for each single molecule. The uniform component as a mixture having a distribution in the degree of polymerization is a positive number in a range that gives the above-mentioned weight average molecular weight as an average value.

In the present invention, the organohydrogenpolysiloxane used as the component (B) undergoes a hydrosilylation addition reaction with the component (A) and acts as a crosslinking agent. This organohydrogenpolysiloxane has an average composition formula (R ¹ ) _x H _y SiO _{(4-xy) / 2} (where R ¹ is a substituted or unsubstituted monovalent carbonization excluding an aliphatic unsaturated group. A hydrogen group, and x and y are positive numbers satisfying 1 ≦ x ≦ 2.2, 0.002 ≦ y ≦ 1 and 1.002 ≦ x + y ≦ 3), and 25 ° C. In which the number of silicon atoms in one molecule (or the degree of polymerization) is from 2 to 300, and particularly from about 3 to 200 is used. be able to. The molecular structure is not particularly limited, and various types such as linear, cyclic, branched, and three-dimensional network (resin-like) structures are used, for example, in the same manner as those usually used in conventional liquid addition-curable silicone rubber compositions Although one can be used, 2 or more (usually about 2 to 200) hydrogen atoms bonded to silicon atoms (that is, about 2 to 200), preferably 3 or more (for example, 3 to 100). It is necessary to include about). In addition, the monovalent organic group (for example, R ¹ group in the above average composition formula) bonded to a silicon atom other than a hydrogen atom of this compound is a substituted or unsubstituted monovalent group in the organopolysiloxane of component (A). Examples of the hydrocarbon group are the same, but a substituted or unsubstituted monovalent hydrocarbon group excluding an aliphatic unsaturated group such as an alkenyl group, particularly a methyl group, a phenyl group, 3,3,3-trimethyl. A fluoropropyl group is preferred.

Examples of the organohydrogenpolysiloxane include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, tris (dimethylhydrogensiloxy) methylsilane, and tris (dimethylhydrogen). Siloxy) Phenylsilane, Trimethylsiloxy group-capped methylhydrogenpolysiloxane at both ends, Trimethylsiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer at both ends, Dimethylhydrogensiloxy group-capped dimethylpolysiloxane at both ends, Dimethylhydrosiloxane at both ends Gensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, both ends trimethylsiloxy group-blocked methylhydrogensiloxane / diphenylsiloxane copolymer , Copolymers comprising both end trimethylsiloxy-blocked methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymer _{(CH 3)} 2 _{HSiO 1/2} units and _{SiO 4/2 units, (CH} 3) 2 HSiO _{1 / 2} units, SiO _4/2 units and (C ₆ H ₅ ) ₁ SiO _1/2 units, and the like. A terminal triorganosiloxy group-blocked organohydrogenpolysiloxane is preferred.

  The addition amount of the component (B) is preferably 2.0 parts by mass or less, and more preferably 1.0 to 2.0 parts by mass with respect to 100 parts by mass of the component (A). If the amount added is too small, the crosslinking density becomes too low. As a result, the heat resistance of the cured silicone rubber may be adversely affected, and the strength may be lowered. On the other hand, if the amount is too large, the surface may not be mirror-like, or the amount may be as bad as the heat resistance. The (B) component organohydrogenpolysiloxane may be used alone or in combination of two or more.

Component (C) dry silica (fumed silica) used in the present invention is for adjusting strength by adding in order to ensure strength, and for suppressing hydrolysis of silicone rubber due to heat. Dry silica is used. As such dry silica, those conventionally known as reinforcing fillers for silicone rubber can be used. For this purpose, the specific surface area by the BET adsorption method is 100 m ² / g or more. Is required, preferably 200 to 600 m ² / g, and more preferably 200 to 400 m ² / g. In addition, the silanol groups present in large numbers on the surface of these silicas are hydrophobized with organopolysiloxane, organopolysilazane, chlorosilane, alkoxysilane, etc., and the surface of the silica fine powder is coated with an organic group such as an ether-bonded alkyl group. Silica is more preferable. This hydrophobization treatment may be performed by mixing the untreated component (C) with the above-mentioned treatment agent in advance before mixing with one or more other components of the silicone rubber composition. When preparing a product, the untreated component (C) may be mixed with the other components and the above-mentioned treating agent under heating to be performed simultaneously with the preparation of the silicone rubber composition. These silicas may be used alone or in combination of two or more. Specific examples of the hydrophobic silica include Aerosil R-812, R-812S, R-972, R-974 (manufactured by Degussa), Rheorosil MT-10 (manufactured by Tokuyama Soda), and Nippon Sil SS series (Nippon Silica). For example).

  The addition amount of the silica of component (C) is preferably 10 to 90 parts by mass, more preferably 40 to 60 parts by mass with respect to 100 parts by mass of component (A). If the amount added is too small, sufficient strength and hardness may not be obtained, and the effect of improving creep resistance may be insufficient. On the other hand, if the amount is too large, the viscosity of the rubber composition becomes too high, and casting may be difficult.

Although it does not specifically limit as a vulcanizing agent of (D) component used by this invention, Preferably, they are a platinum group metal catalyst or a peroxide crosslinking agent. The platinum group metal catalyst is a catalyst for promoting the hydrosilylation addition reaction between the alkenyl group in the component (A) and the SiH group in the component (B). Such a platinum group metal catalyst can crosslink the components (A) and (B) with only thermal energy without generating radicals, and is required to have high temperature durability like a tire vulcanization bladder. Even in cases, there is no polymer cutting and it is used to ensure heat resistance. Further, rubber vulcanized with a platinum group metal catalyst has a rubber network bonded and formed only at a polymer terminal. Examples of the platinum group metal catalyst include platinum black; chloroplatinic acid; alcohol-modified chloroplatinic acid; platinum compounds such as complexes of chloroplatinic acid and olefins, aldehydes, vinyl siloxanes or acetylene alcohols; and rhodium, Examples thereof include compounds containing a platinum group metal such as palladium. Particularly preferably, from the point of compatibility between the component (A) and the component (B), a platinum / vinylsiloxane complex formed by mixing and reacting chloroplatinic acid (H ₂ PtCl ₆ / nH ₂ O) and vinyl siloxane, etc. This is a modified product of silane and siloxane. In this case, vinylsiloxane as a ligand forming a complex with the platinum group metal is a constituent element of the platinum group metal catalyst and does not correspond to the component (A). The amount of the platinum group metal catalyst is preferably 0.1 to 1000 ppm, more preferably 1 to 200 ppm, based on the total mass of the components (A) and (B) in terms of the mass of the platinum group metal. . If the amount added is too small, the crosslinking start temperature becomes too high, which may lead to a delay in the end time. On the other hand, if the amount is too large, crosslinking may start before the casting is completely completed.

  The peroxide cross-linking agent can activate the peroxide with thermal energy, generate radicals, and cross-link the components (A) and (B) with the radicals. In addition, in rubber vulcanized with a peroxide cross-linking agent, the rubber network is not only bonded to the polymer terminal but also bonded to the polymer intermediate part via a vinyl group present in the middle of the polymer. Therefore, even when high temperature durability is required like a tire vulcanization bladder, the rubber network can be sufficiently maintained and high durability can be obtained. Examples of the peroxide cross-linking agent include 2,5-dimethyl-2,5-bis (tertiary butyl peroxy) hexane. Furthermore, the compounding quantity of this peroxide crosslinking agent is 0.2-1.0 mass part suitably with respect to 100 mass parts of said (A) component. If the amount is too small, the crosslinking start temperature becomes too high, which may lead to a delay in the end time. On the other hand, if the amount is too large, crosslinking may start before the casting is completely completed.

  Moreover, in this invention, a metal powder can be mix | blended with a silicone rubber composition as desired. The metal powder is not particularly limited as long as it is a metal powder that can increase the thermal conductivity in the rubber compounding composition, and pure metal powder such as aluminum, gold, silver, and copper can be used. It can be preferably used. The metal powder is preferably a sphere having a particle size of 10 to 500 μm, more preferably 100 to 200 μm. When the metal powder is needle-shaped or plate-shaped, anisotropy appears in the physical properties of the resulting crosslinked product, which is not preferable. The compounding amount of the metal powder is usually 10 parts by mass or less (that is, 0 to 10 parts by mass), preferably 0.5 to 10 parts by mass, more preferably 0. 5 to 5 parts by mass. If the blending amount is too small, the thermal conductivity in the rubber blending composition cannot be sufficiently increased, and the progress of the crosslinking reaction may be different between the surface and the inside. On the other hand, if the amount is too large, the viscosity of the composition becomes too high, and it may be difficult to fill the composition into details during molding. In addition, the casting time is prolonged and workability is deteriorated.

  Furthermore, in this invention, inorganic powder can also be mix | blended with a silicone rubber composition as needed. The inorganic powder is other than the above (C) silica and metal powder, and has an effect of adjusting the heat shrinkage rate of the composition of the present invention. The type of inorganic powder is not particularly limited. For example, mineral powder such as mica, talc, gypsum, calcite, fluorite, apatite and feldspar, clay such as kaolin, zeolite, and glass powder. Etc. can be used. The added amount of the inorganic powder is usually 5 parts by mass or less (that is, 0 to 5 parts by mass), preferably 1 to 5 parts by mass, more preferably 1 to 2 parts by mass with respect to 100 parts by mass of the component (A). It is. If the amount added is too small, the effect of adjusting the composition may be insufficient. On the other hand, if the amount is too large, the viscosity of the composition may become too high and the desired effect may not be achieved.

  Furthermore, in the present invention, various additives conventionally used in silicone rubber compositions can be appropriately added to the silicone rubber composition as necessary. For example, a control agent for adjusting the curing time such as extending the pot life at room temperature, a silane coupling agent, or the like can be added as necessary.

  In the present invention, the preparation of the silicone rubber composition includes, for example, components (A) to (D) and one or more optional components added as necessary, such as planetary mixers and Shinagawa mixers. The mixing means can be used by mixing in any mixing order. In addition, in the intermediate | middle layer 3, it can adjust by adding the said resin compound to a silicone rubber composition, and mixing.

  In the present invention, the butyl rubber which is the main component of the butyl rubber composition is not limited as long as it can be used in a normal tire manufacturing bladder, but an isobutylene-isoprene copolymer or the like can be used. Examples include Butyl 268 (manufactured by Nippon Butyl Co., Ltd.), Butyl 301 (manufactured by Polysar), and the like. In particular, from the viewpoint of adhesiveness with the intermediate layer 3, it is preferable to contain a butyl polymer having a molecular weight of 60 to 1,200,000 as butyl rubber.

  In the present invention, the butyl rubber composition includes chloroprene rubber, chlorosulfonated polyethylene, halogenated butyl rubber, and other halogenated ethylene propylene terpolymer rubbers as other rubber components used as a vulcanization catalyst in addition to butyl rubber. Etc. can be used.

Furthermore, in the present invention, it is preferable that zinc oxide and a formaldehyde resin are contained in the butyl rubber composition. Furthermore, the content of zinc oxide in the butyl rubber composition is X parts by mass, and the content of the formaldehyde resin. Is Y part by mass, the following formula:
X + Y = 3-10
0.3 ≦ X / (X + Y) ≦ 0.7
It is preferable to satisfy the relationship. Thereby, the adhesiveness with the intermediate | middle layer 3 can be made more favorable. In addition, as a formaldehyde resin, the thing similar to the intermediate | middle layer 3 can be used, and it is more preferable that it is the same kind or the same composition as the intermediate | middle layer 3 from an adhesive viewpoint.

  Furthermore, in this invention, it is preferable to add 0.1-1.0 mass part of thiazole compounds in a butyl rubber composition. Such thiazole compounds include, for example, dibenzothiazyl disulfide (MBTS), cyclohexylamine salt of mercaptobenzothiazole (CMBT), N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N-oxydiethylene-2- Benzothiazole sulfenamide (OBS), mercaptobenzothiazole (MBT), Nt-butyl-2-benzothiazole sulfenamide (TBBS), mercaptobenzothiazole zinc salt (ZnMBT) Among the compounds, dibenzothiazyl disulfide is 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.

  Moreover, in this invention, it is preferable to add 10-80 mass parts of carbon black in a butyl rubber composition, and it is more preferable to add 10-60 mass parts. By adding such a range of carbon black, the durability life can be further extended.

  Examples of the carbon black include furnace carbon black such as SAF, ISAF, HAF, FEF, and GPF, acetylene black, and channel carbon black.

  Furthermore, oil can also be added in the present invention. Such oil is not particularly limited, and naphthenic oil, paraffinic oil, aromatic oil, and the like can be used. Among these oils, naphthenic oil is excellent in compatibility with the rubber component and the resin. Series oils are preferred. These oils may be used alone or in a combination of two or more.

  In the present invention, the vulcanization reaction can be suitably performed at a temperature of 120 to 200 ° C, preferably 140 to 180 ° C, more preferably 160 to 170 ° C, and even more preferably 160 ° C.

  In the present invention, after the vulcanization reaction, heat treatment (post cure) is preferably performed at 140 to 175 ° C. for 12 to 48 hours. Thereby, for example, in the silicone rubber composition, residual SiH co-crosslinks to suppress hydrolysis, and therefore, interfacial peeling can be prevented. Further, if the heat treatment temperature is less than 140 ° C., sufficient heat treatment effect may not be obtained. On the other hand, if the heat treatment temperature exceeds 175 ° C., recombination SiH is decomposed to generate free SiH, and a separation nucleus is formed. There is a risk.

  In this invention, it is preferable that the thickness of the intermediate | middle layer 3 is 1-25% of the thickness of the whole bladder for tire manufacture. Specifically, the thickness of the intermediate layer 3 is preferably 0.1 to 1 mm. If the thickness of the intermediate layer 3 is less than 0.1 mm, the strength may be insufficient, while if it exceeds 1 mm, the silicon layer may be peeled off. More preferably, it is 0.3-0.5 mm. More preferably, the film thickness ratio of the outermost layer 1, the intermediate layer 3, and the butyl rubber layer 2 is 49.5: 1: 49.5-37.5: 25: 37.5. In the tire manufacturing bladder 4 of the present invention, the inner butyl rubber layer 2 is preferably 1.5 mm or more from the viewpoint of suppressing permeation of gas or the like, and the outer layer is preferably 1 mm or more from the viewpoint of preventing the outer layer from peeling off. It is not limited to this.

  The tire manufacturing bladder of the present invention is a tire vulcanizing bladder used for imparting a final product tire shape at the time of vulcanization, or by assembling each component of the tire in the tire manufacturing process to prepare a raw tire (unvulcanized). It can be used as a tire molding bladder used when molding a tire). In particular, it is preferably used as a tire vulcanization bladder for good releasability from a tire under high temperature conditions and prevention of hydrolysis of the silicone rubber composition.

  Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by the following description.

Example 1
A tire manufacturing bladder was manufactured under the conditions shown in Table 1 below. As a silicone rubber composition, KE1310ST manufactured by Shin-Etsu Chemical Co., Ltd. (composition contains vinyl group-containing dimethylpolysiloxane (main agent), silica filler (30% by mass) and platinum catalyst (vulcanizing agent) (0.3% by mass)) Cat. 1310 L [composition contains vinyl group-containing dimethylpolysiloxane (main agent) and methylhydrogenpolysiloxane (crosslinking agent)], 10 parts by weight, aluminum powder (particle size 100 μm), 5 parts by weight, mica powder, 2 parts by weight The outermost layer was prepared using a mixture of a part and 1.5 parts by mass of a crosslinking controller (manufactured by Shin-Etsu Chemical Co., Ltd .: NO6). Moreover, the intermediate | middle layer was produced using what mixed 100 mass parts of silicone rubber compositions similar to the above, and 8 mass parts of resin compounds (Tacchi roll 201, Taoka Chemical Industry Co., Ltd.). Further, as a butyl rubber composition, 100 parts by mass of JSR Butyl 268, 5 parts by mass of chloroprene rubber (manufactured by Showa Neoprene: Neoprene W), 40 parts by mass of carbon black (manufactured by Toshiba Carbon: 600A), and 5 parts of zinc oxide A butyl rubber layer was prepared by using 3 parts by mass of stearic acid, 5 parts by mass of a resin vulcanizing agent (Taoka Chemical Industry Co., Ltd .: Tactrol 201), and 5 parts by mass of aroma oil. The thickness of the intermediate layer was 0.4 mm, the total thickness at the center of the bladder was 5 mm, and the outermost layer and the butyl rubber layer were the same thickness. In Table 1, the presence or absence of each layer is shown.

(Example 2)
A tire manufacturing bladder was prepared in the same manner as in Example 1 except that tack roll 160 (manufactured by Taoka Chemical Industry Co., Ltd.) was used as the resin compound of the intermediate layer.

(Comparative Example 1)
A tire manufacturing bladder was manufactured in the same manner as in Example 1 except that the intermediate layer was not provided.

Obtained using a tire building bladder, a tire vulcanization of a tire size PSR215 / 60R15.5 vulcanization time 15 min (13 kg / cm ² steam pressure by a pressure time of 5 minutes, then 10 minutes internal pressure 21 kg / cm ^It was repeated until the bladder was punctured in ² ), and its service life (vulcanization durability, times) was evaluated. These results are also shown in Table 1 below using an index with Comparative Example 1 as 100. In addition, it shows that vulcanization durability is so favorable that the numerical value of an index | exponent is large.

  As shown in Table 1 above, it was confirmed that the tire manufacturing bladders of Examples 1 and 2 had very high vulcanization durability compared to the tire manufacturing bladder of Comparative Example 1.

1 Outermost layer 2 Butyl rubber layer 3 Middle layer 4 Tire manufacturing bladder

Claims (12)

A bladder for tire production consisting of a plurality of layers, comprising an outermost layer containing a silicone rubber composition, and a butyl rubber layer containing a butyl rubber composition,
A tire manufacturing bladder comprising an intermediate layer including a silicone rubber composition and a resin compound between the outermost layer and the butyl rubber layer.   The tire manufacturing bladder according to claim 1, wherein the resin compound is a phenol resin or a formaldehyde resin.   The bladder for tire manufacture according to claim 1 or 2, wherein the intermediate layer includes 0.7 to 16 parts by mass of the resin compound with respect to 100 parts by mass of the silicone rubber composition. The silicone rubber composition is
(A) a linear diorganopolysiloxane containing an alkenyl group bonded to two or more silicon atoms in one molecule;
(B) Average composition formula (R ¹ ) _x H _y SiO _{(4-xy) / 2} (where R ¹ is a substituted or unsubstituted monovalent hydrocarbon group excluding an aliphatic unsaturated group, x and y are each a positive number satisfying 1 ≦ x ≦ 2.2, 0.002 ≦ y ≦ 1, and 1.002 ≦ x + y ≦ 3), and two or more in one molecule An organohydrogenpolysiloxane containing hydrogen atoms bonded to silicon atoms of
(C) dry silica having a specific surface area of 100 m ² / g or more,
(D) The bladder for tire manufacture as described in any one of Claims 1-3 containing a vulcanizing agent.   The tire manufacturing bladder according to claim 4, wherein the vulcanizing agent is a platinum group metal catalyst or a peroxide crosslinking agent.   The silicone rubber composition contains, as the (A) diorganopolysiloxane, a dimethylsiloxane polymer having a vinyl group in the polymer of 1.0 mol% or less and a molecular weight of 60 to 1,200,000. 5. The tire manufacturing bladder according to 5.   The silicone rubber composition contains 2.0 parts by mass or less of the (B) organohydrogenpolysiloxane with respect to 100 parts by mass of the (A) diorganopolysiloxane. The bladder for manufacturing a tire according to Item. The (C) dry silica is high-strength silica having a specific surface area of 200 to 400 m ² / g, and the silicone rubber composition is 40 to 60 parts by mass with respect to 100 parts by mass of the (A) diorganopolysiloxane. The bladder for tire manufacture as described in any one of Claims 4-7 containing the said (C) dry-type silica.   The bladder for tire manufacture according to any one of claims 1 to 8, wherein the butyl rubber composition contains a butyl polymer having a molecular weight of 60 to 1,200,000 as butyl rubber.   The bladder for tire manufacture according to any one of claims 1 to 9, wherein the butyl rubber composition contains 10 to 60 parts by mass of carbon black with respect to 100 parts by mass of the butyl rubber. The butyl rubber composition contains zinc oxide and a formaldehyde resin,
When the content of the zinc oxide in the butyl rubber composition is X parts by mass, and the content of the formaldehyde resin is Y parts by mass,
X + Y = 3-10
0.3 ≦ X / (X + Y) ≦ 0.7
The bladder for tire manufacture according to any one of claims 1 to 10 satisfying the relationship:   The thickness of the said intermediate | middle layer is 1-25% of the thickness of the whole bladder for tire manufacture, The bladder for tire manufacture as described in any one of Claims 1-11.

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