JP7606340B2 - Release agent composition for molding and vulcanizing rubber products and its use - Google Patents

Description

The present invention relates to a release agent composition for molding and vulcanizing rubber products and its use.

When molding and vulcanizing a rubber product, a rubber bag called a bladder or air bag (hereinafter sometimes referred to as a bladder) is inserted inside the raw rubber, which is the rubber product before molding and vulcanization, and a high-temperature, high-pressure gas (e.g., steam at about 180°C) or liquid is introduced into the inside of the bladder to expand the bladder, and the raw rubber is pressed against a mold to be heated and pressurized, and molded and vulcanized to produce a rubber product.
When the rubber product is a tire, the bladder is inserted inside the tire before molding and vulcanization (hereinafter sometimes referred to as a green tire), the bladder is expanded, and the green tire is pressed against a mold, heated and pressurized, and molded and vulcanized. In this case, since both the bladder and the inner surface of the green tire are made of rubber, a release agent is required between them.

Conventionally, in the molding and vulcanization of tires, for example, a method has been used in which a water-based or solvent-based release agent, known as "inside paint," is applied to the inner surface of a green tire each time, or a method has been used in which a silicone-based release agent is applied to the surface of the bladder to improve the release between the green tire and the bladder.
For example, Patent Document 1 proposes an aqueous diorganopolysiloxane emulsion in which inorganic silicate whose surface has been hydrophobized by reaction with an organosilicon compound is dispersed as an inside paint. However, the method of applying inside paint to the inner surface of a green tire each time has the problem that the process becomes complicated and the surroundings of the equipment are soiled during application. In addition, there is a bigger problem than this problem, in that the inside paint penetrates into the joint of the tire inner liner, causing peeling of the joint of the inner liner and resulting in tire defects, and a huge amount of space is required for the stock point until the tire after the inside paint is applied is put into the molding process.

Therefore, as a method different from the inside painting, there is a method of applying a silicone-based release agent to the bladder surface to improve the release between the green tire and the bladder.As a release agent composition for the bladder, for example, Patent Document 2 proposes a method of using a vulcanization bladder that is surface-treated with a silicone composition containing organopolysiloxane, methylhydrogenpolysiloxane, silica, and a metal organic acid salt.
However, in the method of coating the bladder surface with a silicone-based release agent, the adhesiveness to the bladder is insufficient, so the release property during the molding vulcanization process is weak, and there is a problem that the release coating deteriorates in a short time, especially when molding and vulcanization are performed continuously, causing defects in the rubber products being manufactured. Also, in a composition containing a reactive polysiloxane such as methylhydrogenpolysiloxane and a catalyst such as an organic salt, there is a problem that the reaction proceeds during storage and the viscosity increases, thereby worsening productivity.

As described above, the release agents of Patent Documents 1 and 2 each have problems. However, the current situation is that there is no choice but to use conventional inside paint release agents and bladder release agent compositions, despite the problems of releasability and workability.

Japanese Unexamined Patent Publication No. 53-42243 Japanese Unexamined Patent Publication No. 62-275711

The object of the present invention is to provide a release agent composition for molding vulcanization of rubber products that has good stability during storage, excellent releasability for bladders during the molding vulcanization process of rubber products, and allows continuous molding vulcanization, and to provide an efficient method for manufacturing rubber products using this release agent composition for molding vulcanization.

As a result of intensive research, the present inventors have found that the above problems can be solved by a release agent composition for molding and vulcanizing rubber products containing specific components, and have arrived at the present invention.
That is, the release agent composition for molding and vulcanizing rubber products of the present invention contains a silicone oligomer (A) and a surfactant (B), and the silicone oligomer (A) has a hydrolyzable group.

In the release agent composition for molding vulcanization of rubber products of the present invention, the total ratio of the molecular weight of the hydrolyzable groups to the molecular weight of the silicone oligomer (A) is preferably 2 to 50%.
In the release agent composition for molding vulcanization of rubber products of the present invention, the silicone oligomer (A) preferably has a branched structure and/or a cyclic structure.
In the release agent composition for molding vulcanization of rubber products of the present invention, the content of the surfactant (B) is preferably 5 to 40 parts by weight per 100 parts by weight of the silicone oligomer (A).
It is preferable that the release agent composition for molding and vulcanizing a rubber product of the present invention further contains another polysiloxane (C) other than the silicone oligomer (A).
The release agent composition for molding and vulcanizing a rubber product of the present invention preferably further contains a water-soluble polymer (D).
The release agent composition for molding and vulcanizing a rubber product of the present invention preferably further contains an inorganic component (E).

The method for producing a rubber product of the present invention is a method for producing a rubber product by molding and vulcanizing unvulcanized rubber, and includes step 1 of adhering the above-mentioned release agent composition for molding vulcanization of rubber products to the rubber on the surface of a bladder and/or the surface of the unvulcanized rubber on the side that comes into contact with the bladder, and step 2 of, after step 1, heating and expanding the bladder contained in the unvulcanized rubber in a molding die, thereby pressing the surface of the unvulcanized rubber on the side that does not come into contact with the bladder against the inner surface of the molding die, thereby molding and vulcanizing the unvulcanized rubber.
In the method for producing a rubber product of the present invention, the rubber product is preferably a tire.

The release agent composition for molding and vulcanizing rubber products of the present invention has good stability during storage and is excellent in releasability from a bladder during the molding and vulcanization process of rubber products, and enables efficient continuous molding and vulcanization of rubber products.
Furthermore, the method for producing a rubber product of the present invention uses the above-mentioned release agent composition for molding and vulcanizing a rubber product, so that the rubber product can be produced efficiently.

The release agent composition for molding and vulcanizing rubber products of the present invention contains a silicone oligomer (A) and a surfactant (B).
First, each component constituting the release agent composition for molding and vulcanizing rubber products of the present invention (hereinafter, sometimes simply referred to as the release agent composition) will be described in detail.

[Silicone Oligomer (A)]
The release agent composition of the present invention contains a silicone oligomer (A) having a hydrolyzable group (hereinafter, sometimes simply referred to as component (A)). Component (A) is a component that imparts film-forming properties and release properties. Furthermore, component (A) does not necessarily require the use of a catalyst, and can suppress the progress of the reaction during storage and can have good storage stability.
Component (A) is an inorganic siloxane bond (Si-O-Si) having a relatively small molecular weight, and the molecular weight is not particularly limited, but is preferably 200 to 10,000, more preferably 300 to 9,000, even more preferably 500 to 8,000, and particularly preferably 750 to 7,000. When the molecular weight of component (A) is within the above range, the film-forming property tends to be improved. In the present invention, the molecular weight of component (A) means the weight average molecular weight.

Examples of the hydrolyzable group contained in component (A) include alkoxy groups such as methoxy, ethoxy, propoxy, and butoxy groups; alkoxy-substituted alkoxy groups such as methoxyethoxy, ethoxyethoxy, and methoxypropoxy groups; acyloxy groups such as acetoxy, octanoyloxy, and benzoyloxy groups; alkenyloxy groups such as vinyloxy, propenyloxy, isopropenyloxy, isobutenyloxy, and cyclohexenyloxy groups; dimethylketoxy, Examples of hydrolyzable groups include ketoxime groups such as N-methylamino group, N,N-dimethylamino group, N,N-diethylamino group, N-butylamino group, and cyclohexylamino group; aminooxy groups such as N,N-dimethylaminooxy group and N,N-diethylaminooxy group; amide groups such as N-methylacetamide group, N-ethylacetamide group, and N-methylbenzamide group; hydroxy groups; and epoxy groups. The hydrolyzable group possessed by component (A) may be one type or two or more types of the above hydrolyzable groups.
The hydrolyzable group is preferably at least one selected from an alkoxy group, an alkoxy-substituted alkoxy group, an acyloxy group, an alkenyloxy group, a ketoxime group, and an amide group, which allows efficient film formation.

The ratio of the total molecular weight of hydrolyzable groups in the molecular weight of component (A) (the molecular weight of all hydrolyzable groups in component (A)) to the molecular weight of component (A) is not particularly limited, but is preferably 2 to 50%, more preferably 3 to 45%, even more preferably 4 to 40%, and particularly preferably 5 to 35%. When the ratio of the total molecular weight of hydrolyzable groups in the molecular weight of component (A) is 2% or more, the film formability tends to be improved, and when the ratio of the total molecular weight of hydrolyzable groups in the molecular weight of component (A) is 50% or less, the strength of the resulting film tends to be improved.

When component (A) has a branched structure and/or a cyclic structure, the strength of the coating film to be formed can be increased, which is preferable.
The branched structure contains T units represented by R ¹ SiO _3/2 in its structure, where R ¹ is bonded to a silicon atom. It is preferable that each R ¹ in the T unit is independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group, or a hydrolyzable group.

In the T unit, when R ¹ bonded to a silicon atom is a substituted or unsubstituted monovalent hydrocarbon group, the total number of carbon atoms in the substituted or unsubstituted monovalent hydrocarbon group is not particularly limited, but is preferably 1 to 20, more preferably 1 to 12, and even more preferably 1 to 8.
Examples of monovalent hydrocarbon groups which R ¹ can take include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, and decyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl, allyl, isopropenyl, 1-butenyl, and 2-butenyl; aryl groups such as phenyl, vinylphenyl, tolyl, xylyl, and naphthyl; and aralkyl groups such as benzyl, phenethyl, and phenylpropyl.
Further, the substituted monovalent hydrocarbon groups include those having a group (substituent) in which some or all of the hydrogen atoms bonded to the carbon atoms of these monovalent hydrocarbon groups are substituted with other atoms or groups. Examples of such substituents include halogen atoms such as chlorine atoms, fluorine atoms, and bromine atoms, hydroxyl groups, amino groups, vinyl groups, epoxy groups, glycidyloxy groups, mercapto groups, acryloyloxy groups, methacryloyloxy groups, carboxy groups, cyano groups, and isocyanate groups.
Each R ¹ in the T unit is independently preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted phenyl group, a vinyl group, or a hydrolyzable group, and more preferably an unsubstituted alkyl group having 1 to 8 carbon atoms, an unsubstituted phenyl group, or a hydrolyzable group.

The cyclic structure contains at least one unit selected from T units represented by ^R2SiO3 / ₂ and D units represented by ^R3R4SiO2 _/2 ^, and ^R2 , ^R3 and ^R4 are all bonded to silicon atoms. It is preferable that ^R2 in the T units and R3 and ^R4 in the D ^units are each independently a hydrogen atom, the above-mentioned substituted or unsubstituted monovalent hydrocarbon group, or a hydrolyzable group.

[Surfactant (B)]
The surfactant (B) (hereinafter, sometimes simply referred to as component (B)) is a component that assists in "wetting" the unvulcanized rubber and/or the rubber on the surface of the bladder. By including component (B), the release agent composition can be uniformly attached to the unvulcanized rubber and/or the rubber on the surface of the bladder.
Here, in surface chemistry, "wetting" is defined as a phenomenon in which one fluid on the surface of a solid or liquid is replaced by another liquid. For example, when a solid/gas interface is replaced by a solid/liquid interface, the solid is said to be wetted by a liquid. Therefore, when it is expressed that the release agent composition of the present invention has wetted the unvulcanized rubber and/or the rubber on the bladder surface, it means that the interface between the rubber and air on the unvulcanized rubber and/or the bladder surface has been replaced by the interface between the rubber and the release agent composition on the unvulcanized rubber and/or the bladder surface. When it is expressed that the release agent composition of the present invention does not sufficiently wet the unvulcanized rubber and/or the rubber on the bladder surface, it means that the interface between the rubber and air on the unvulcanized rubber and/or the bladder surface has not been completely replaced by the interface between the rubber and the release agent composition on the unvulcanized rubber and/or the bladder surface.

Component (B) may include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, etc., and may contain one or more types. If component (B) is a nonionic surfactant and/or an anionic surfactant, it is preferable from the viewpoint of imparting wettability to the unvulcanized rubber and/or the rubber on the bladder surface.

Examples of nonionic surfactants include polyoxyalkylene alkyl ethers such as polyoxyethylene cetyl ether, polyoxyethylene lauryl ether, and polyoxyethylene polyoxypropylene lauryl ether; polyoxyalkylene alkyl phenyl ethers such as polyoxyethylene nonylphenyl ether and polyoxyethylene octylphenyl ether; polyoxyalkylene fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monooleate; sorbitan fatty acid esters such as sorbitan monopalmitate and sorbitan monooleate; polyoxyethylene sorbitan monostearate, polyoxyethylene Examples of the nonionic surfactant include polyoxyalkylene sorbitan fatty acid esters such as ethylene sorbitan monooleate; glycerin fatty acid esters such as glycerin monostearate, glycerin monopalmitate, and glycerin monolaurate; polyoxyalkylene castor oil; polyoxyalkylene hydrogenated castor oil; polyoxyalkylene sorbitol fatty acid esters; polyglycerin fatty acid esters; alkyl glycerin ethers; polyoxyalkylene cholesteryl ethers; alkyl polyglucosides; sucrose fatty acid esters; polyoxyalkylene alkylamines; and oxyethylene-oxypropylene block polymers. One or more of these may be used in combination. Among these, it is preferable that the nonionic surfactant is at least one selected from polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenyl ethers, as this provides excellent wetting of the unvulcanized rubber and/or the rubber on the bladder surface.

Examples of anionic surfactants include fatty acid salts such as sodium oleate, potassium palmitate, and triethanolamine oleate; alkyl sulfate ester salts such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium stearyl sulfate, and sodium cetyl sulfate; polyoxyalkylene alkyl ether acetates such as sodium polyoxyethylene tridecyl ether acetate; alkyl benzene sulfonates such as sodium dodecylbenzene sulfonate; polyoxyalkylene alkyl ether sulfates; sodium stearoyl methyl taurate, sodium lauroyl methyl taurate, sodium myristoyl methyl taurate, and sodium palmitoyl methyl taurate. Examples of the anionic surfactant include higher fatty acid amide sulfonates, N-acyl sarcosine salts such as sodium lauroyl sarcosine, alkyl phosphates such as sodium monostearyl phosphate, polyoxyalkylene alkyl ether phosphate salts such as sodium polyoxyethylene oleyl ether phosphate and sodium polyoxyethylene stearyl ether phosphate, long-chain sulfosuccinates such as sodium di-2-ethylhexyl sulfosuccinate and sodium dioctyl sulfosuccinate, long-chain N-acyl glutamate salts such as sodium monosodium N-lauroyl glutamate and disodium N-stearoyl-L-glutamate, and the like. One or more of these may be used in combination. Among these, it is preferable that the anionic surfactant is at least one selected from fatty acid salts, alkyl sulfates, alkylbenzene sulfonates, polyoxyalkylene alkyl ether sulfates, higher fatty acid amide sulfonates, polyoxyalkylene alkyl ether phosphates, and long-chain sulfosuccinates, since they exhibit excellent wetting of the unvulcanized rubber and/or the rubber on the bladder surface.

Examples of the cationic surfactant include alkyltrimethylammonium salts such as stearyltrimethylammonium chloride, lauryltrimethylammonium chloride, and cetyltrimethylammonium bromide; dialkyldimethylammonium salts; trialkylmethylammonium salts; and alkylamine salts. One or more of these may be used in combination.
Examples of the amphoteric surfactant include imidazoline-based amphoteric surfactants such as 2-undecyl-N,N-(hydroxyethylcarboxymethyl)-2-imidazoline sodium and 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt; betaine-based amphoteric surfactants such as 2-heptadecyl-N-carboxymethyl-N-hydroxyethylimidazolium betaine, lauryl dimethylaminoacetic acid betaine, amidopropyl betaine, alkyl betaine, amido betaine, and sulfobetaine; and amino acid amphoteric surfactants such as N-lauryl glycine, N-lauryl β-alanine, and N-stearyl β-alanine. One or more of these may be used in combination.

The amount of component (B) contained in the release agent composition of the present invention is not particularly limited relative to 100 parts by weight of component (A), but is preferably 5 to 40 parts by weight, more preferably 6 to 39 parts by weight, even more preferably 7 to 38 parts by weight, and particularly preferably 8 to 37 parts by weight. When the content of component (B) is 5 parts by weight or more, sufficient wetting of the unvulcanized rubber and/or the rubber on the bladder surface tends to be achieved. On the other hand, when the content of component (B) is 40 parts by weight or less, foaming tends to be suppressed.

[Other polysiloxanes (C)]
The release agent composition of the present invention may further contain a polysiloxane (C) (hereinafter, sometimes simply referred to as component (C)) other than the component (A). The further inclusion of component (C) is preferable in terms of improving the release properties.
Component (C) is at least one selected from silicone oil, silicone rubber, and silicone resin. Examples of component (C) include dialkyl polysiloxanes such as dimethyl polysiloxane, diethyl polysiloxane, methyl isopropyl polysiloxane, and methyl dodecyl polysiloxane; alkyl phenyl polysiloxanes such as methyl phenyl polysiloxane, dimethyl siloxane-methyl phenyl siloxane copolymer, and dimethyl siloxane-diphenyl siloxane copolymer; alkyl aralkyl polysiloxanes such as methyl (phenyl ethyl) polysiloxane and methyl (phenyl propyl) polysiloxane; and 3,3,3-trifluoropropyl methyl polysiloxane. One or more of the above may be used in combination. In addition, an emulsion of component (C) may be used when producing the release agent composition.

When the release agent composition of the present invention contains component (C), its content is not particularly limited, but is preferably 0.1 to 25 parts by weight, more preferably 0.2 to 20 parts by weight, even more preferably 0.3 to 15 parts by weight, and particularly preferably 0.4 to 10 parts by weight, relative to 100 parts by weight of component (A). When the content of component (C) is 0.1 part by weight or more, the release properties tend to improve. On the other hand, when the content of component (C) is 25 parts by weight or less, the adhesion tends to improve.

[Water-soluble polymer (D)]
The release agent composition of the present invention may further contain a water-soluble polymer (D) (hereinafter, sometimes simply referred to as component (D)). When the release agent composition further contains component (D), This is preferable in terms of improving the adhesion of the coating.
Examples of the component (D) include starches such as oxidized starch, starch acetate, starch phosphate, carboxymethyl starch, carboxyethyl starch, hydroxyethyl starch, cationic starch, cyanoethylated starch, and dialdehyde starch; mannan; alginic acid; alginates such as sodium alginate, propylene glycol alginate, triethanolamine alginate, and ammonium alginate; methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl methyl cellulose; cellulose ethers such as cellulose, hydroxyethyl ethyl cellulose, carboxymethyl cellulose and its salts; natural gums such as taracant gum, gum arabic, guar gum, xanthan gum, British gum, glucomannan, gellan gum, tara gum, locust bean gum, carrageenan; polyacrylic acid soda; polyvinyl alcohol; polyethylene glycol; polyethylene oxide; water-soluble acrylic resin; water-soluble urethane resin; water-soluble melamine resin; water-soluble epoxy resin; water-soluble butadiene resin; water-soluble phenol resin, etc., can be used alone or in combination. The above may be used in combination.
Among these, it is preferable that component (D) is at least one selected from carboxymethyl cellulose and its salts, guar gum, and xanthan gum.

When the release agent composition of the present invention contains component (D), its content is not particularly limited, but is preferably 0.1 to 25 parts by weight, more preferably 0.2 to 20 parts by weight, even more preferably 0.3 to 15 parts by weight, and particularly preferably 0.4 to 10 parts by weight, relative to 100 parts by weight of component (A). When the content of component (D) is 0.1 part by weight or more, the adhesion of the release agent composition tends to improve. On the other hand, when the content of component (D) is 25 parts by weight or less, the handleability of the release agent composition tends to improve.

The release agent composition of the present invention may further contain an inorganic component (E) (hereinafter, sometimes simply referred to as component (E)). When the component (E) is further contained, the strength of the coating film to be formed can be improved, which is preferable.
Examples of component (E) include carbonates such as calcium carbonate, magnesium carbonate, barium carbonate, etc.; silicates such as kaolin, aluminum silicate, calcium silicate, clay, talc, mica, sericite, bentonite, etc.; sulfates such as calcium sulfate, barium sulfate, etc.; metal oxides such as silica, alumina, magnesium oxide, antimony trioxide, titanium oxide, white carbon, iron oxide, etc.; metal hydroxides such as aluminum hydroxide, magnesium hydroxide, iron hydroxide, etc.; red iron oxide; carbon black; graphite, etc., and one or more of these may be used in combination.
Among these, it is preferable that component (E) is at least one selected from calcium carbonate, magnesium carbonate, kaolin, clay, talc, mica, sericite, and silica.

When the release agent composition of the present invention contains component (E), its content is not particularly limited, but is preferably 0.1 to 25 parts by weight, more preferably 0.2 to 20 parts by weight, even more preferably 0.3 to 15 parts by weight, and particularly preferably 0.4 to 10 parts by weight, relative to 100 parts by weight of component (A). When the content of component (E) is 0.1 part by weight or more, the strength of the coating film formed tends to be improved. On the other hand, when the content of component (E) is 25 parts by weight or less, the adhesion of the release agent composition tends to be improved.

〔water〕
The release agent composition of the present invention may further contain water. By containing water, the handleability of the release agent composition can be improved, which is preferable.
The water may be tap water, ion-exchanged water, distilled water, or the like.
When the release agent composition of the present invention contains water, the content of water is not particularly limited, but is preferably 150 to 15,000 parts by weight, more preferably 180 to 5,000 parts by weight, further preferably 210 to 3,000 parts by weight, and particularly preferably 240 to 2,000 parts by weight, relative to 100 parts by weight of the content of component (A). When the content of water is within the above range, the coatability of the release agent composition tends to be improved. In addition, when the release agent composition contains water, it may be an aqueous dispersion in which components other than water are dispersed or dissolved in water.

[Other ingredients]
The release agent composition of the present invention may further contain, in addition to the components described above, metal soaps, waxes, polymer particles, antifoaming agents, preservatives, catalysts, and the like.
Examples of metal soaps include magnesium laurate, calcium laurate, zinc laurate, magnesium myristate, calcium myristate, zinc myristate, magnesium palmitate, calcium palmitate, zinc palmitate, magnesium stearate, calcium stearate, zinc stearate, aluminum trioctadecanoate, aluminum dioctadecanoate, aluminum monooctadecanoate, calcium octadecanoate, zinc octadecanoate, magnesium octadecanoate, barium octadecanoate, and the like, and one or more of these may be used in combination.

Examples of waxes include vegetable waxes, animal waxes, mineral waxes, petroleum waxes, synthetic hydrocarbon waxes, modified waxes, hydrogenated waxes, fatty acid amides, and phthalic anhydride imide waxes, and these may be used alone or in combination of two or more.
Examples of vegetable waxes include candelilla wax, carnauba wax, rice wax, Japan wax, jojoba oil, sugar wax, bayberry wax, oculi wax, esparto wax, and the like, and one or more of these may be used in combination.
Examples of animal waxes include beeswax, lanolin, spermaceti, insect wax, shellac wax, etc., and these may be used alone or in combination of two or more kinds.
Examples of mineral waxes include montan wax, ozokerite, and ceresin, and one or more of these may be used in combination.
Examples of the petroleum wax include paraffin wax, microcrystalline wax, petrolatum, etc., and one or more of these may be used in combination.
Examples of synthetic hydrocarbon waxes include Fischer-Tropsch wax and polyethylene wax, and these may be used alone or in combination of two or more kinds.

Examples of modified waxes include montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives, and these may be used alone or in combination of two or more kinds.
Examples of hydrogenated waxes include hydrogenated castor oil, 12-hydroxystearic acid, 12-hydroxystearic acid amide, N-hydroxyethyl-12-hydroxystearylamide, N,N'-ethylene-bis-12-hydroxystearylamide, N,N'-hexamethylene-bis-12-hydroxystearylamide, N,N'-xylylene-bis-12-hydroxystearylamide, methyl-12-hydroxystearate, propylene glycol-mono-12-hydroxystearate, and ethylene glycol-mono-12-hydroxystearate, and one or more of these may be used in combination.
Examples of the polymer particles include particles made of polystyrene, polyacrylonitrile, polymethacrylonitrile, polymethyl (meth)acrylate, etc., and one or more of these may be used in combination.

Examples of defoaming agents include oil-based defoaming agents such as castor oil, sesame oil, linseed oil, and animal and vegetable oils; fatty acid-based defoaming agents such as stearic acid, oleic acid, and palmitic acid; fatty acid ester-based defoaming agents such as isoamyl stearate, distearyl succinate, ethylene glycol distearate, and butyl stearate; alcohol-based defoaming agents such as polyoxyalkylene monohydric alcohol di-t-amylphenoxyethanol, 3-heptanol, and 2-ethylhexanol; di-t-amylphenoxyethanol, 3-heptanol, and 2-ethylhexanol; Examples of such defoamers include ether-based defoamers such as nonoxyethanol, 3-heptyl cellosolve, nonyl cellosolve, and 3-heptyl carbitol; phosphate-based defoamers such as tributyl phosphate and tris(butoxyethyl) phosphate; amine-based defoamers such as diamylamine; amide-based defoamers such as polyalkylene amide and acylate polyamine; sulfate-based defoamers such as sodium lauryl sulfate; paraffin-based mineral oil; naphthene-based mineral oil; and the like. These may be used alone or in combination of two or more.

Examples of preservatives include thiazoles such as thiazole and 2-mercaptothiazole; thiocyanates such as methylene bisthiocyanate and ammonium thiocyanate; sulfimides such as o-benzoic sulfimide and phenylmercuric-o-benzoic sulfimide; alkyl dialkyl thiocarbamates such as methyl dimethyl thiocarbamate and ethyl diethyl dithiocarbamate; thiuram sulfides such as tetramethyl thiuram sulfide and tetraethyl thiuram sulfide; thiuram disulfides such as tetramethyl thiuram disulfide and tetraethyl thiuram disulfide; dithiocarbamates such as ferric diethyl dithiocarbamate and lead dimethyl dithiocarbamate; sulfamides such as o-toluenesulfonamide and benzenesulfonanilide; 1- Aminosulfonic acids such as aminonaphthyl-4-sulfonic acid and 1-amino-2-naphthol-4-sulfonic acid; phenols such as pentachlorophenol and o-phenylphenol and their alkali metal salts; chlorinated quinones such as tetrachloro-p-benzoquinone and 2,3-dichloro-1,4-naphthoquinone; nitro group-containing compounds such as dinitrocaprylphenylcrotonate and dinitro-o-cresol; triazines such as 1,3,5-trihydroxyethylhexahydro-1,3,5-triazine and 1,3,5-triethylhexahydro-1,3,5-triazine; organic mercury compounds such as phenylmercuric phthalate and o-hydroxyphenylmercuric chloride; iodine-containing compounds such as 1,3-diiodo-2-propanol, and the like may be used alone or in combination.

Examples of catalysts include organic tin compounds such as dibutyltin diacetate, dibutyltin dioctylate, and dibutyltin dilaurate; organic aluminum compounds such as aluminum tris(acetylacetone), aluminum tris(ethyl acetoacetate), and aluminum diisopropoxy(ethyl acetoacetate); zirconium (acetylacetone), zirconium tris(acetylacetone), zirconium tetrakis(ethylene glycol monomethyl ether), zirconium tetrakis(ethylene glycol monoethyl ether), and zirconium tetrakis(ethylene glycol monobutyl ether). Examples of the organic compounds include organic zirconium compounds such as titanium tetrakis (ethylene glycol monomethyl ether), titanium tetrakis (ethylene glycol monoethyl ether), and titanium tetrakis (ethylene glycol monobutyl ether); mineral acids such as hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid; organic acids such as formic acid, acetic acid, oxalic acid, and trifluoroacetic acid; inorganic bases such as ammonia, sodium hydroxide, and potassium hydroxide; organic bases such as ethylenediamine and alkanolamine; amino compounds such as aminosilane, silazane, and amines, and one or more of these may be used in combination. Among these, at least one selected from organic tin compounds, organic aluminum compounds, organic titanium compounds, mineral acids, and amino compounds is preferable.

[Release agent composition for molding and vulcanization of rubber products and its manufacturing method]
The viscosity of the release agent composition of the present invention at 25°C is not particularly limited, but is preferably 0.1 to 20,000 mPa·s, more preferably 0.1 to 5,000 mPa·s, even more preferably 1 to 1,000 mPa·s, and particularly preferably 1 to 500 mPa·s. When the viscosity of the release agent composition is 0.1 mPa·s or more, the wettability of the release agent composition tends to be improved. On the other hand, when the viscosity of the release agent composition is 20,000 mPa·s or less, the adhesion of the release agent composition tends to be improved. The viscosity of the release agent composition can be measured by using a B-type rotational viscometer, for example.

The pH of the release agent composition of the present invention at 25°C is not particularly limited, but is preferably 3 to 12, more preferably 3 to 11, even more preferably 3 to 10, and particularly preferably 3 to 9. When the pH of the release agent composition for molding vulcanization is in the above range, the handleability of the release agent composition tends to be improved.

The surface tension of an aqueous solution of the release agent composition of the present invention having a solids concentration of 0.1% by weight at 20°C is not particularly limited, but is preferably 20 to 50 mN/m, more preferably 21 to 45 mN/m, even more preferably 22 to 40 mN/m, and particularly preferably 23 to 35 mN/m. When the surface tension of the release agent composition for molding vulcanization is within the above range, the adhesion of the release agent composition tends to be improved.

The release agent composition of the present invention may be an emulsion. When the release agent composition is in an emulsion state, it is preferable because the film-forming property is improved. When the release agent composition is an emulsion, the average particle size of the emulsion is not particularly limited, but is preferably 0.001 to 200 μm, more preferably 0.01 to 150 μm, even more preferably 0.05 to 100 μm, and particularly preferably 0.1 to 50 μm. When the average particle size of the release agent composition for molding vulcanization is 0.001 μm or more, the stability of the release agent composition tends to be improved. On the other hand, when the average particle size of the release agent composition for molding vulcanization is 200 μm or less, the film-forming property tends to be improved.

The method for producing the release agent composition of the present invention can include, for example, a method of mixing component (A), component (B), and, if necessary, components (C) to (E), water, and other components. In the method for producing the release agent composition, the mixing order is not particularly limited, and all of the components may be mixed at the same time, or each component may be mixed in order, or some components may be mixed in advance and the remaining components may be added and mixed later.
The mixing method is not particularly limited, and can be carried out using a device equipped with a very simple mechanism such as a container and a stirring blade. Among them, the use of an emulsifying device such as a homomixer, homogenizer, colloid mill, or line mixer can efficiently produce the mixture.

[Method of manufacturing rubber products]
The method for producing a rubber product of the present invention is a method for producing a rubber product by molding and vulcanizing unvulcanized rubber, which includes step 1 of adhering the above-mentioned release agent composition to the rubber on the surface of a bladder and/or the surface of the unvulcanized rubber on the side that comes into contact with the bladder, and step 2 of molding and vulcanizing the unvulcanized rubber by heating and expanding the bladder contained in the unvulcanized rubber in a mold after step 1, thereby pressing the surface of the unvulcanized rubber on the side that does not come into contact with the bladder against the inner surface of the mold, thereby efficiently producing a rubber product. It is also preferable that the rubber product is a tire.

A bladder is a rubber bag used when molding and vulcanizing the raw material unvulcanized rubber (when the rubber product is a tire, it is called a green tire). The bladder is inserted inside the unvulcanized rubber (the side where the unvulcanized rubber comes into contact with the bladder) and a high-temperature, high-pressure gas (for example, steam at about 180°C) or liquid is introduced into the bladder to expand it, and the unvulcanized rubber is pressed against a mold to be heated and pressurized, thereby performing molding and vulcanization.
There are no particular limitations on the shape of the bladder, etc. Examples of the shape include a sheet, a film, a hose, a tube, a sponge, a packing, a belt, etc., and the bladder may have grooves engraved therein to allow air to escape during vulcanization molding.

In step 1, the method of attaching the release agent composition to the rubber on the bladder surface and/or the surface of the unvulcanized rubber on the side that comes into contact with the bladder can be, for example, sprayed onto the rubber on the bladder surface in a mist using a spray gun, sprayed onto the rubber on the bladder surface in a fine stream, applied to the rubber on the bladder surface with a brush, or immersed the rubber on the bladder surface and/or the unvulcanized rubber in the release agent composition.

When the release agent composition is applied to the rubber on the bladder surface in step 1, curing may be performed between steps 1 and 2 until a coating is formed on the bladder surface. When curing until a coating is formed, the period is not particularly limited, but is preferably 0.01 to 168 hours, more preferably 0.01 to 120 hours, particularly preferably 0.01 to 72 hours, and most preferably 0.01 to 24 hours. If the curing period is within the above range, the coating tends to be efficiently formed.

The atmospheric temperature for curing the bladder surface before the coating is formed is not particularly limited, but is preferably 0 to 200°C, more preferably 10 to 190°C, particularly preferably 20 to 180°C, and most preferably 30 to 170°C. When the atmospheric temperature is within the above range, the coating tends to be formed efficiently.

In step 1, if the release agent composition is applied to the surface of the unvulcanized rubber on the side that comes into contact with the bladder, it is believed that when the rubber on the bladder surface comes into contact with the unvulcanized rubber, some or all of the release agent composition is transferred to the rubber on the bladder surface, forming a coating with releasability on the bladder surface, allowing efficient continuous molding and vulcanization of rubber products. In this case, the coating can also be formed when the unvulcanized rubber is molded and vulcanized.

There are no particular limitations on the thickness of the coating formed on the bladder surface, but it is preferably 0.01 to 1000 μm, more preferably 0.01 to 500 μm, even more preferably 0.01 to 250 μm, and particularly preferably 0.1 to 100 μm. If the thickness of the coating after curing is within the above range, the productivity of rubber products tends to improve.

The weight per unit area of the coating formed on the bladder surface is not particularly limited, but is preferably 0.1 to 200 g/m ² , more preferably 0.5 to 150 g/m ² , even more preferably 1 to 100 g/m ² , and particularly preferably 3 to 50 g/m ^2. When the weight per unit area of the coating is within the above range, the productivity of rubber products tends to improve.

The bladder having the coating formed from the release agent composition applied in step 1 exhibits good releasability in step 2 which is carried out after step 1, and can increase the number of molding and vulcanization of rubber products and reduce the defective rate of rubber products.
Examples of the molding method in step 2 include calendar roll sheet molding, roller head sheet molding, extrusion sheet molding, ram extrusion molding, screw extrusion molding, compression molding, casting molding, and injection molding.

The temperature during molding and vulcanization in step 2 is not particularly limited, but is preferably 100 to 300°C, more preferably 110 to 260°C, further preferably 120 to 220°C, and particularly preferably 130 to 180°C.
The pressure during molding and vulcanization in step 2 is not particularly limited, but is preferably 0.1 to 50 kgf/cm ² , more preferably 0.2 to 45 kgf/cm ² , still more preferably 0.3 to 40 kgf/cm ² , and particularly preferably 0.5 to 35 kgf/cm ² .

Examples of rubber products obtainable by the manufacturing method of the present invention include tires, hoses, anti-vibration rubber, automobile belts, seals, fenders, conveyor belts, elastic sleepers, rubber pads, rubber mats, seismic isolation rubber, sealing materials, waterproofing agents, rubber electric wires, rubber cables, condoms, rubber gloves, rubber balloons, gaskets, packing, rubber balls, etc., with tires being preferred. There are no particular limitations on the tires, but examples include automobile tires for passenger cars, automobile tires for trucks and buses, automobile tires for sports cars, tires for racing cars, tires for aircraft, tires for two-wheeled automobiles, tires for bicycles, tires for buggies, tires for agricultural use, rubber crawlers, etc.

Below, examples and comparative examples of the release agent composition for molding and vulcanizing rubber products are specifically described. Note that the present invention is not limited to these examples. In the following, the release agent composition for molding and vulcanizing rubber products may be referred to as the "release agent composition" for simplicity.

[Evaluation of releasability]
The release agent composition was applied to the surface of a bladder rubber sheet (4 cm × 7 cm × 0.5 cm, mainly made of IIR rubber) in an amount of 10 g/ ^m2 , and the sheet was heated to a temperature of 160° C. to promote the reaction, thereby forming a coating on the surface of the bladder rubber sheet, thereby obtaining a treated bladder rubber sheet.
The treated bladder rubber sheet and an unvulcanized rubber sheet (4 cm x 7 cm x 0.5 cm, mainly IIR) were overlapped and press-vulcanized for 20 minutes under conditions of 160°C and 20 kgf/ ^cm2 . The vulcanized evaluation rubber sheet and the bladder rubber sheet were peeled off at 180 degrees, and the peel load required at that time was measured with a tensile tester to evaluate the releasability.
The evaluation criteria for releasability are as follows, with ⊚ and ◯ being acceptable. Note that if peeling had already occurred at the end of vulcanization, a tensile test could not be performed, but the releasability was obviously excellent, so it was rated as ⊚.
⊚: Peeled off with a tensile load of less than 0.5 N, and excellent releasability.
◯: Peeled off with a tensile load of 0.5 N or more and less than 1.0 N, and the releasability is somewhat excellent.
Δ: Peeled off under a tensile load of 1.0 N or more and less than 1.5 N, and releasability was somewhat poor.
x: Peeled off under a tensile load of 1.5 N or more, poor releasability.

[Evaluation of repeated release properties]
The treated bladder rubber sheet used in the evaluation of the above mold releasability was repeatedly vulcanized in the same manner as above, and the number of times the mold releasability could be maintained was measured. The more times the vulcanization could be repeated, the better the mold releasability. The evaluation of the mold releasability was performed according to the following criteria.
⊚: Even after repeated vulcanization 20 times or more, the mold is released with a tensile load of less than 1.0 N, and the mold is excellent in repeated release property.
◯: Released with a tensile load of less than 1.0 N between 10 or more and less than 20 times, and the repeated continuous release property is somewhat excellent.
Δ: Released at a tensile load of less than 1.0 N between 5 or more and less than 10 times, and the repeated release properties are somewhat poor.
x: Released with a tensile load of less than 1.0 N in less than five tries, poor releasability.

[Evaluation of storage stability]
The release agent composition was placed in a plastic container and left to stand for one month in thermostatic chambers at 5° C., 25° C., and 40° C., respectively, and the change in state was observed. The stability during storage was evaluated according to the following criteria.
⊚: No change in state was observed at any temperature, and the storage stability was excellent.
◯: Viscosity increased and separation occurred at either temperature, but the product was easily redispersed, and the storage stability was somewhat excellent.
Δ: Viscosity increased and separation occurred at any temperature, and redispersion was not easily achieved. Storage stability was somewhat poor.
×: At any temperature, the polyethylene container expands due to gas generation, and the storage stability is poor.

[Evaluation of molding vulcanization test of passenger car tires]
The release agent composition was applied at 10 g/ ^m2 to the rubber on the surface of a bladder (surface area: 6000 ^cm2 ) for molding and vulcanizing passenger car tires, and heated to a temperature of 160°C to promote the reaction and form a coating on the bladder rubber surface, thereby obtaining a treated bladder.
Using this treated bladder, a molding and curing test for passenger car tires was repeatedly performed, and the number of times that tires could be produced without any defects was measured. The molding and curing test for passenger car tires was evaluated according to the following criteria.
⊚: Even when molding and vulcanization were repeatedly performed 30 times or more, the mold releasability remained good.
◯: Molding and vulcanization can be repeatedly performed 20 or more times but less than 30 times with good releasability.
Δ: Molding and vulcanization can be repeatedly performed 10 or more and less than 20 times with good releasability.
x: Molding and vulcanization could be repeatedly performed for less than 10 times with good releasability.

[Evaluation of mold vulcanization tests for bicycle tires]
The release agent composition was applied at 10 g/ ^m2 to the rubber on the surface of a bladder (surface area: 1500 ^cm2 ) for molding and vulcanizing a bicycle tire, and heated to a temperature of 160°C to promote the reaction and form a coating on the bladder rubber surface, thereby obtaining a treated bladder.
Using this treated bladder, a molding and curing test for a bicycle tire was repeatedly performed, and the number of times that a tire could be produced without a defect was measured. The molding and curing test for a bicycle tire was evaluated according to the following criteria.
⊚: Even when molding and vulcanization were repeatedly performed 30 times or more, the mold releasability remained good.
◯: Molding and vulcanization can be repeatedly performed 20 or more and less than 30 times with good releasability.
Δ: Molding and vulcanization can be repeatedly performed 10 or more and less than 20 times with good releasability.
x: Molding and vulcanization could be repeatedly performed for less than 10 times with good releasability.

Example 1
A release agent composition was obtained by mixing 20 g of silicone oligomer 1, 4 g of POE(7) lauryl ether, and 76 g of tap water.
The obtained release agent composition was applied to the surface of a bladder rubber sheet in an amount of 10 g/m ² and heated to a temperature of 160° C. to form a coating on the surface of the bladder rubber sheet, thereby obtaining a treated bladder rubber sheet.
The treated bladder rubber sheet and the unvulcanized rubber sheet were stacked and press-vulcanized for 20 minutes at 160°C and 20 kgf/ ^cm2 . After molding and vulcanization, the rubber sheet peeled off and had excellent releasability. The treated bladder rubber sheet was then used to repeatedly perform molding and vulcanization. As a result, the releasability was maintained for 30 cycles, and the rubber sheet had excellent releasability.
Furthermore, the obtained release agent composition was placed in a plastic container and left to stand for one month in thermostatic chambers at 5° C., 25° C., and 40° C., respectively. No change in state was observed at any of the temperatures, and the composition was found to have excellent stability during storage.

(Examples 2 to 20)
In Examples 2 to 20, release agent compositions were obtained and evaluated in the same manner as in Example 1, except that the compositions in Example 1 were changed as shown in Table 1. The results are shown in Tables 1 to 3, respectively.

Example 21
The release agent composition obtained in Example 1 was applied in an amount of 10 g/ ^m2 to each of a bladder for molding and vulcanizing a passenger tire and a bladder for molding and vulcanizing a bicycle tire, and heated to a temperature of 160° C. to form a coating, thereby obtaining each of the treated bladders.
Using each of the treated bladders, tire molding and vulcanization tests were repeatedly performed. The number of times that tires could be produced without any problems was 50 times for passenger car tires and 100 times for bicycle tires, and the mold releasability was good (respective evaluations: ⊚).

(Comparative Example 1)
A comparative release agent composition was obtained by mixing 20 g of hydrogenpolysiloxane, 0.02 g of dibutyltin diacetate, 4 g of POE(7) lauryl ether, and 75.98 g of tap water.
The comparative release agent composition obtained was applied to the surface of the bladder rubber sheet ^at 10 g/m2, and heated to a temperature of 160°C to form a coating on the surface of the bladder rubber sheet, thereby obtaining a comparative treated bladder rubber sheet. The comparative treated bladder rubber sheet obtained and an unvulcanized rubber sheet were overlapped and press-vulcanized for 20 minutes under conditions of 160°C and 20 kgf/ ^cm2 . The tensile load at the time of peeling the molded and vulcanized rubber sheet was 0.1 N, and the releasability was excellent. After that, continuous vulcanization was repeatedly performed using the treated bladder rubber sheet, but the releasability could only be maintained six times, and the releasability was somewhat poor in repeated vulcanization.
In addition, the comparative release agent composition was placed in a plastic container and left to stand for one month in thermostatic chambers at 5° C., 25° C., and 40° C., respectively. As a result, an increase in viscosity and expansion of the container due to gas generation were confirmed at 25° C. and 40° C., and the stability during storage was poor.

(Comparative Examples 2 to 5)
In Comparative Examples 2 to 5, comparative release agent compositions were obtained and evaluated in the same manner as in Comparative Example 1, except that the compositions in Comparative Example 1 were changed as shown in Table 4. The results are shown in Table 4.

In Tables 1 to 4, "POE(n)" means "polyoxyethylene having n repeating oxyethylene groups," and "POE(7) lauryl ether" means "polyoxyethylene lauryl ether having 7 repeating oxyethylene groups."
Table 5 shows the details of the raw materials used in the above examples and comparative examples.

As can be seen from Tables 1 to 3, the release agent compositions of Examples 1 to 20 are release agent compositions containing a silicone oligomer (A) having a hydrolyzable group and a surfactant, and are able to solve the problem of the present application.
On the other hand, when the silicone oligomer (A) having a hydrolyzable group is not contained as in Comparative Examples 1, 2, 4, and 5, and when the surfactant (B) is not contained as in Comparative Example 3, the problem of the present application cannot be solved.

Claims (9)

Contains a silicone oligomer (A) and a surfactant (B),
The release agent composition for molding and vulcanizing a rubber product, wherein the silicone oligomer (A) has a hydrolyzable group and a branched structure and/or a cyclic structure . The release agent composition for molding and vulcanizing rubber products according to claim 1, wherein the total proportion of the molecular weight of the hydrolyzable groups in the molecular weight of the silicone oligomer (A) is 2 to 50%. 3. The release agent composition for molding and vulcanizing a rubber product according to claim 1 or 2, wherein the branched structure contains T units represented by R ¹ SiO _3/2 in its structure , and R ¹ in the T units is each independently a hydrogen atom, a substituted or unsubstituted monovalent hydrocarbon group, or a hydrolyzable group . 4. The release agent composition for molding and vulcanizing a rubber product according to claim 1, wherein the content of the surfactant (B) is 5 to 40 parts by weight per 100 parts by weight of the silicone oligomer (A). The mold release agent composition for molding and vulcanizing rubber products according to any one of claims 1 to 4, further comprising another polysiloxane (C) other than the silicone oligomer (A). The release agent composition for molding and vulcanizing a rubber product according to any one of claims 1 to 5, further comprising a water-soluble polymer (D). The release agent composition for molding and vulcanizing rubber products according to any one of claims 1 to 6, further comprising an inorganic component (E). A method for producing a rubber product by molding and vulcanizing unvulcanized rubber, comprising the steps of:
A step 1 of adhering the mold release agent composition for molding vulcanization of a rubber product according to any one of claims 1 to 7 to a rubber on a surface of a bladder and/or a surface of the unvulcanized rubber on a side in contact with the bladder;
The method for producing a rubber product includes, after step 1, step 2 of heating and expanding the bladder contained in the unvulcanized rubber within a mold, thereby pressing the surface of the unvulcanized rubber that is not in contact with the bladder against the inner surface of the mold, thereby molding and vulcanizing the unvulcanized rubber. The method for producing a rubber product according to claim 8, wherein the rubber product is a tire.