JP2019006952A - Silicone rubber composition containing block polyisocyanate composition, manufacturing method of coating article, and coating article - Google Patents

Abstract

To provide a silicone rubber composition containing a block polyisocyanate composition and a curable silicone rubber composition, having good compatibility with the block polyisocyanate composition and the curable silicone rubber composition, of which adhesiveness is not reduced with time course, and which strongly adheres even by coating an unrefined or refined fabric having hydrolyzability and oil agent amount of 5 mass% or less of fabric weight with the same and curing the same, especially a silicone rubber composition suitable for an air bag.SOLUTION: There is provided a silicone rubber composition containing a block polyisocyanate composition and a curable silicone rubber composition, in which the block polyisocyanate composition contains polyisocyanate and a heat dissociable block agent.SELECTED DRAWING: None

Description

The present invention relates to a silicone rubber composition containing a block polyisocyanate composition and a curable silicone rubber composition, the compatibility between the block polyisocyanate composition and the curable silicone rubber composition is good, and the silicone rubber composition The adhesiveness of the article does not decrease with time, and the silicone rubber composition is coated on a woven fabric that is unscoured or scoured, and the amount of oil agent is 5% by mass or less of the fabric weight, and is cured. The present invention also relates to a silicone rubber composition that strongly adheres, a method for producing a coating, and a coating. The present invention particularly relates to a silicone rubber composition suitable for an airbag, a method for producing a coating, and a coating.

A coating produced by coating a curable silicone rubber composition on a resin and curing it is used in many fields. However, if a lot of spinning oil at the time of production remains in the fabric, the silicone rubber composition There was a problem that the cured product and the fabric were not bonded. Therefore, in the production, a scouring process for removing the oil component of the fabric is necessary. For example, in Patent Document 1, the amount of the oil component and the oil agent is limited to promote adhesion with the silicone rubber composition. Furthermore, although a method of adding a silicone compound to the oil agent is disclosed, it takes time and effort to manage the components and amount of the oil agent and to manage the equipment of the scouring process.

On the other hand, in order to increase the adhesive strength, a silicone rubber composition has been conventionally blended with a component that improves adhesiveness. Particularly in airbag applications, it is difficult to suppress leakage of high-pressure gas and maintain the sustainability of expansion time, and strong adhesiveness is required to achieve the purpose. As such a component, for example, Patent Document 2 discloses an isocyanate compound, but the effect of adhesion is limited to triallyl isocyanurate, and there are descriptions and knowledge about the state of scouring of fabrics and oil agents. Not shown at all. Conventionally, since triallyl isocyanurate is a solid, it has a disadvantage that it is not compatible with the silicone rubber composition and is difficult to disperse. The fabric was insufficient and could not be bonded to the fabric having a large amount of residual oil. As a method for improving the compatibility, there is a method of blending an organic solvent. However, blending of an organic solvent is not preferred from the viewpoint of the environment, and there is a demand for a solvent with little or no solvent.

In addition, since the isocyanate group has high reactivity, the reaction proceeds in the silicone rubber composition and the adhesiveness gradually decreases. Therefore, it was not possible to formulate a composition kit in advance. Therefore, even if the isocyanate compound is added at the time of blending the silicone rubber composition kit, the adhesiveness is lost with the passage of time, so that the pot life is short, and practically no industrial production was possible. As what can control the reactivity of an isocyanate group, for example, Non-Patent Document 1 describes a completely solvent-free low-viscosity blocked polyisocyanate composition. No findings are shown.

Thus, the silicone rubber composition containing the conventional block polyisocyanate composition and the curable silicone rubber composition has good compatibility between the block polyisocyanate composition and the curable silicone rubber composition, and the silicone rubber composition The adhesiveness of the composition does not decrease with time, and the silicone rubber composition is coated on a woven fabric that has been scoured or scoured and the amount of oil agent is 5% by mass or less of the fabric weight, and is cured. However, there is a problem in strongly bonding, and a silicone rubber composition that realizes such a problem has been demanded.

JP 2012-177220 A JP 2007-186596 A

“Coating Time Report” 2015 No. No. 235 (Asahi Kasei Chemicals Corporation)

The present invention has been made in view of the above circumstances, and relates to a silicone rubber composition containing a blocked polyisocyanate composition and a curable silicone rubber composition, and relates to a block polyisocyanate composition and a curable silicone rubber composition. Good compatibility, the adhesiveness of the silicone rubber composition does not decrease with time, and is a scoured or scoured silicone rubber composition, the amount of oil agent being 5% by mass of the fabric weight An object of the present invention is to provide a silicone rubber composition which is coated on a woven fabric and adheres strongly even when cured, and particularly suitable for an airbag.

As a result of intensive studies, the present inventors have found that the object can be achieved by using a block polyisocyanate composition having a particularly low viscosity, and have completed the present invention.

That is, the present invention is a silicone rubber composition containing a block polyisocyanate composition and a curable silicone rubber composition, wherein the block polyisocyanate composition contains a polyisocyanate and a heat dissociable blocking agent. It is characterized by.

According to the present invention, the silicone rubber composition containing the block polyisocyanate composition and the curable silicone rubber composition has good compatibility between the block polyisocyanate composition and the curable silicone rubber composition, and the silicone rubber composition Adhesiveness does not decrease over time, and the silicone rubber composition is coated on a scoured or scoured woven fabric whose amount of oil is 5% by mass or less of the woven fabric weight and is strong even when cured. Therefore, the work load of the scouring process can be greatly reduced and the productivity can be improved.

Details of the silicone rubber composition according to the present invention will be described below.

The curable silicone rubber composition of the present invention comprises a composition kit of at least one kind of silicone rubber composition, these composition kits are mixed, cured by reaction, and finally the silicone rubber composition. Any material can be used as long as a cured product can be obtained. Examples of such curing methods include peroxide curing, condensation curing, addition curing, ultraviolet curing, and electron beam curing. The preferred curing method of the present invention bonds to silicon atoms in one molecule. For organopolysiloxanes having an alkenyl group, a method of crosslinking the Si-H group of the organohydrogenpolysiloxane with an addition reaction catalyst, a method of crosslinking with an organic peroxide, or silicon at both ends of the molecular chain. This is a method in which an Si-H group of an organohydrogenpolysiloxane is crosslinked with a condensation reaction catalyst with respect to an organopolysiloxane having a hydroxy group or an alkoxy group bonded to an atom.

(Ingredient (A))
Component (A) is a main component constituting the curable silicone rubber composition, and is a main material of the silicone rubber composition for obtaining excellent rubber properties after curing. Component (A-1) is an organopolysiloxane containing, on average, 1.8 or more alkenyl groups bonded to silicon atoms in one molecule, and the average composition formula is generally It is represented by Formula (1).
R ² _a SiO _{(4-a) / 2} (1)
(In the formula (1), R ² is an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms that is the same or different from each other. A is 1.7 to 2.1. is there.)

Here, at least two of the monovalent hydrocarbon groups represented by R ² are alkenyl such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group, isobutenyl group, hexenyl group, and cyclohexenyl group. The other group is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 18 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl Group, tert-butyl group, pentyl group, neopentyl group, hexyl group, 2-ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group and other alkyl groups, cyclopentyl group, cyclohexyl group, cycloheptyl group, etc. Aryl such as cycloalkyl group, phenyl group, tolyl group, xylyl group, biphenyl group, naphthyl group Groups, benzyl groups, phenylethyl groups, phenylpropyl groups, methylbenzyl groups and other aralkyl groups, and chloromethyl groups in which some or all of the hydrogen atoms in these hydrocarbon groups are substituted by halogen atoms, cyano groups, etc. , 2-bromoethyl group, 3,3,3-trifluoropropyl group, 3-chloropropyl group, cyanoethyl group and other halogen-substituted alkyl groups, cyano-substituted alkyl groups, and the like.

In selecting R ^2, a vinyl group is preferable as the alkenyl group required for two or more, and a methyl group, a phenyl group, and a 3,3,3-trifluoropropyl group are preferable as the other groups. Moreover, it least 70 mol% of all R ² is a methyl group, preferably in terms of physical properties and economy of the cured product, usually is used those having more than 80 mol% is methyl groups.

The organopolysiloxane of component (A-1) may be linear or branched. The molecular structure includes dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain, dimethylsiloxane / methylphenylsiloxane copolymer blocked with dimethylvinylsiloxy group at both ends of the molecular chain, and dimethylsiloxane / methylvinylsiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain. Copolymer, dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer with both ends of molecular chain, trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer with both ends of molecular chain, and some of the methyl groups of these organopolysiloxanes Or all alkyl groups such as ethyl group and propyl group; aryl groups such as phenyl group and tolyl group; halogenated groups such as 3,3,3-trifluoropropyl group Illustrative examples include organopolysiloxanes substituted with alkyl groups, and mixtures of two or more of these organopolysiloxanes, but they are linear organopolysiloxanes having vinyl groups at both ends of the molecular chain for ease of availability. Those are preferred.

Component (A-2) is an organopolysiloxane having hydroxy groups bonded to silicon atoms at both ends of the molecular chain and / or an organopolysiloxane having alkoxy groups bonded to silicon atoms at both ends of the molecular chain. It may be linear or branched. Examples of the alkoxy group include a methoxy group and an ethoxy group, and a methoxy group is preferable from the viewpoint of reactivity. Except for the hydroxy group and the alkoxy base, it is preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms which is the same or different from each other, specifically a methyl group, an ethyl group, a propyl group. Alkyl groups such as isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, 2-ethylhexyl group, heptyl group, octyl group, nonyl group, decyl group, dodecyl group, cyclopentyl group Cycloalkyl groups such as cyclohexyl group and cycloheptyl group, aryl groups such as phenyl group, tolyl group, xylyl group, biphenyl group and naphthyl group, aralkyl groups such as benzyl group, phenylethyl group, phenylpropyl group and methylbenzyl group Or some or all of the hydrogen atoms in these hydrocarbon groups are halogenated A halogen-substituted alkyl group such as a chloromethyl group, 2-bromoethyl group, 3,3,3-trifluoropropyl group, 3-chloropropyl group, cyanoethyl group, cyano-substituted alkyl group, etc. In the present invention, a methyl group is preferable from the viewpoints of physical properties and economics of the cured product, and those having a methyl group of 80 mol% or more are usually used.

The organopolysiloxane of component (A) is produced by a method known to those skilled in the art, and the viscosity at 25 ° C. is preferably 50 to 1,000,000 mPa · s, more preferably 200 to 500,000 mPa · s, and particularly the viscosity. It is preferable to use two or more different types because the viscosity of the final silicone rubber composition can be easily adjusted. The viscosity can be measured with a rotational viscometer or the like.

(Ingredient (B))
The block polyisocyanate composition of component (B) is a main component for strongly bonding a silicone rubber composition to a woven fabric that has been scoured or scoured, and the amount of oil agent is 5% by mass or less of the fabric weight. It is an essential component of the invention. The conventional block polyisocyanate compound has a drawback that it is difficult to handle because the viscosity is very high due to the strong intramolecular hydrogen bond of the urethane group and urea group generated when the polyisocyanate used as a raw material and the blocking agent are reacted. there were. In addition, since the isocyanate content in the molecule is small, it was necessary to increase the blending amount in order to strongly adhere to the base fabric, but the viscosity was high and it was difficult to handle, and it was not compatible with the curable silicone rubber composition. Therefore, sufficient adhesion could not be obtained due to separation or poor dispersion. As a result of intensive studies, the present inventors have found that a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, and a block polyisocyanate containing a heat dissociable blocking agent When a low-viscosity block polyisocyanate composition that is substantially free of organic solvents and has a viscosity at 60 ° C. of 100,000 mPa · s or less is used, the compatibility with the curable silicone rubber composition is improved. As a result, the dispersion of the block polyisocyanate composition is improved, the adhesiveness of the silicone rubber composition does not decrease with time, and the scoured or scoured fabric has an oil amount. Even if the fabric is 5 mass% or less of the fabric weight, It has been found that there is to be effective.

Examples of the aliphatic diisocyanate include butane diisocyanate, pentane diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. Among these, hexamethylene diisocyanate is preferable from the viewpoint of industrial availability. These aliphatic diisocyanates may be used alone or in combination of two or more. Examples of the alicyclic diisocyanate include isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, and 1,4-cyclohexane diisocyanate. Among these, isophorone diisocyanate is preferable from the viewpoint of industrial availability. These alicyclic diisocyanates may be used alone or in combination of two or more.

Either an aliphatic diisocyanate or an alicyclic diisocyanate may be used alone, or two or more of the aliphatic diisocyanate and the alicyclic diisocyanate may be used in combination.

The blocking agent is not particularly limited as long as it is thermally dissociable and meets the purpose of the present invention. The blocking agent protects the isocyanate group, prevents deactivation of the isocyanate group due to moisture and the like, and prevents the curing catalyst from being poisoned by the isocyanate group, so that it can be stabilized and maintained even in the silicone composition. The term “thermal dissociation” here means that the blocking agent bonded to the isocyanate group is dissociated by heating, but the temperature required for dissociation varies depending on the structure of the blocking agent, for example, 40 ° C. to 300 ° C. It is. Immediately after the blocking agent is dissociated, the isocyanate group can act as an adhesive.
Of these, those selected from oxime, acid amide, amine, active methylene, and pyrazole compounds are preferably used singly or in combination because of their industrial availability. Methyl ethyl ketoxime, acetoxime , Methanol, ethanol, acetanilide, acetic acid amide, ε-caprolactam, diphenylamine, aniline, ethyl acetoacetate, 3-methylpyrazole, 3.5-dimethylpyrazole and the like.

The block polyisocyanate composition of the present invention does not substantially contain an organic solvent, but “substantially does not contain” means that the content of the organic solvent in the block polyisocyanate composition is 5% by mass or less. Furthermore, 3 mass% or less is preferable from a viewpoint of environmental load reduction, and 1 mass% or less is more preferable. Also, the lower the viscosity, the better the compatibility, and the better the compatibility. From the viewpoint of ease of handling, the viscosity is preferably 100,000 mPa · s or less at 60 ° C., and the ease of mixing is preferably 30,000 mPa · s or less at 60 ° C. More preferred. For the viscosity measurement, an E-type viscometer can be used up to 25,600 mPa · s, and a rheometer (RS-1 manufactured by HAAKE) can be used beyond that. Moreover, a rotor can be selected according to a viscosity.

0.01-5 mass parts is preferable with respect to 100 mass parts of components (A), and, as for the compounding quantity of a component (B), 0.02 mass part-3 mass parts is more preferable. If it is 0.01 part or less, the proportion of the isocyanate group exposed from the beginning becomes large, so that it is deactivated by moisture or the like, so that it is difficult to obtain an adhesive effect.

(Ingredient (C))
Any curing catalyst can be used as long as it is used for curing the curable silicone rubber composition. The catalyst used for the addition reaction is a catalyst known to those skilled in the art that accelerates the addition curing reaction between an alkenyl group and a hydrogen atom bonded to a silicon atom. Specifically, platinum group metals such as platinum, rhodium, palladium, osmium, iridium, ruthenium, or the like, which are fixed to a particulate carrier material (for example, activated carbon, aluminum oxide, silicon oxide), platinum compounds Examples include platinum halides, platinum-olefin complexes, platinum-alcohol complexes, platinum-alcolate complexes, platinum-vinylsiloxane complexes, dicyclopentadiene-platinum dichloride, cyclooctadiene-platinum dichloride, cyclopentadiene-platinum dichloride, and the like. Is done.

Further, for economic reasons, a metal compound catalyst other than a noble metal may be used. Specifically, as the hydrosilylated iron catalyst, an iron-carbonyl complex catalyst, an iron catalyst having a cyclopentadienyl group as a ligand, Terpyridine ligand, iron catalyst with terpyridine ligand and bistrimethylsilylmethyl group, iron catalyst with biiminopyridine ligand, iron catalyst with biiminoquinoline ligand, aryl group coordination An iron catalyst having a cyclic or acyclic olefin group having an unsaturated group, and an iron catalyst having a cyclic or acyclic olefinyl group having an unsaturated group. Other examples include hydrosilylation cobalt catalysts, vanadium catalysts, ruthenium catalysts, iridium catalysts, samarium catalysts, nickel catalysts, manganese catalysts, and the like.

The catalyst can also be used in the form of microencapsulation in a fine particle solid or the like. In this case, the fine particle solid containing a catalyst and insoluble in the organopolysiloxane is, for example, a thermoplastic resin (for example, a polyester resin or a silicone resin). The catalyst can also be used in the form of an inclusion compound, for example in a cyclodextrin.

The effective amount according to the desired curing temperature and curing time is used as the catalyst blending amount. Usually, the catalyst metal element concentration is 0.5 to 1,000 ppm with respect to the total mass of the silicone rubber composition. It is sufficient that the ratio is 1 to 500 ppm, more preferably 1 to 100 ppm. When the blending amount is less than 0.5 ppm, curing may be remarkably slow or may not be cured. On the other hand, when it exceeds 1,000 ppm, the cost increases, which is not economically preferable.

As a catalyst used for the reaction by the organic peroxide, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, o-chlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl Peroxide, 2,4-dicumyl peroxide, 2,5-dimethyl-bis (2,5-t-butylperoxy) hexane, di-t-butyl peroxide, t-butylperbenzoate, 1,1- Examples thereof include bis (t-butylperoxycarboxy) hexane, and these organic peroxides are used in the range of 0.1 to 5 parts by mass per 100 parts by mass of the component (A-1).

Catalysts used in the condensation reaction include dibutyltin diacetate, bis (acetoxydibutyltin) oxide, bis (lauroxydibutyltin) oxide, dibutyltin bisacetylacetonate, dibutyltin bismaleic acid monobutyl ester, dioctyl bismaleic acid monobutyl ester, etc. Organotin catalysts and the like are exemplified, and these condensation reaction catalysts are used in the range of 0.1 to 20 parts by mass per 100 parts by mass of the component (A-2).

(Component (D))
Component (D) is an organohydrogenpolysiloxane having an average of two or more hydrogen atoms bonded to silicon atoms in one molecule, and reacts with component (A) to act as a crosslinking agent. Specifically, methylhydrogenpolysiloxane, dimethylsiloxane / methylhydrogenpolysiloxane copolymer, methylphenylsiloxane / methylhydrogenpolysiloxane copolymer, cyclic methylhydrogenpolysiloxane, dimethylhydrogensiloxy unit and SiO _Examples thereof include a copolymer composed of _4/2 units. The amount of the organohydrogenpolysiloxane blended is preferably such that the hydrogen atoms bonded to the silicon atoms are 0.5 to 20 moles relative to the total of the alkenyl groups of the component (A-1). When the amount is less than 0.5 mol, the hardness is remarkably lowered. When the amount is more than 20 mol, the hardness becomes too hard and the cured film is liable to be cracked or peeled off.

The viscosity of the organohydrogenpolysiloxane of component (D) at 25 ° C. is preferably 1 to 100,000 mPa · s, more preferably 2 to 5,000 mPa · s. These may be used alone or in combination of two or more. May be.

In particular, an organohydrogen having hydrogen atoms bonded to silicon atoms only at both ends of the molecular chain when it is desired to follow the stretchable fabric by improving the elongation of the cured product of the silicone rubber composition. It is good to contain polysiloxane. These are preferably linear, and high elongation can be easily obtained by increasing the molecular chain length of the organopolysiloxane having an alkenyl group as the component (A-1) relatively easily by a curing reaction.

In addition, from the viewpoint of elongation and adhesiveness, both ends of the molecular chain and those containing hydrogen atoms other than both ends may be contained. Specifically, as shown by the following general formula (2) A linear organohydrogenpolysiloxane is exemplified.

HR ³ ₂ SiO— (HR ³ SiO) _m — (R ³ ₂ SiO) _n —SiR ³ ₂ H (2)

In the formula (2), R ³ independently represents an unsubstituted or halogen-substituted monovalent hydrocarbon group having 1 to 10 carbon atoms which is the same or different and does not have an aliphatic unsaturated bond. A positive number of 50, n is 0 or a positive number of 1 to 150, and t represented by the formula: t = m / (m + n) satisfies 0.01 ≦ t ≦ 1.0. M in the formula (2) is more preferably 1 to 20, n is more preferably 10 to 100, t is 0.02 ≦ t ≦ 1.0, and further preferably t is 0.00. 02 ≦ t ≦ 0.2. When m is 50 or more, the elongation at break does not increase, and when n is 150 or more, the hardness of the cured product decreases. Further, when t is 0.01 or less, the hardness of the cured product is lowered, which is not preferable, and when it is 0.1 or more, the elongation at break of the cured product is hardly increased.

From the viewpoint of adhesion and heat resistance, both ends of the molecular chain of the organohydrogenpolysiloxane have trimethylsiloxy groups, and contain an organohydrogenpolysiloxane containing at least one aromatic group in the molecule. In addition, for economic reasons, the aromatic group is preferably a phenyl group. Furthermore, when these are combined with an organohydrogenpolysiloxane having both ends of the molecular chain having a trimethylsiloxy group and no aromatic group in the molecule, the hydrogen content is 5 mmol / g or more. This is preferable because adhesion is further promoted.

(Ingredient (E))
The component (E) silica is a component having a function as a reinforcing material, and examples thereof include fumed silica, silica fume, precipitated silica, calcined silica, colloidal silica, and diatomaceous earth having hydrophilicity or hydrophobicity. In particular, they are preferably fine powders, have a particle size of 100 μm or less, a specific surface area of 50 m ² / g or more, more preferably 150 m ² / g or more. In addition, silica that has been surface-treated in advance with organosilane, organosilazane, organocyclopolysiloxane, or the like can also be suitably used. The amount of component (E) added is usually in the range of 0.5 to 50 parts by weight, preferably 1 to 30 parts by weight, per 100 parts by weight of component (A). You may use these individually or in combination of multiple types. If the amount is too small, the desired physical properties such as tear strength cannot be obtained. If the amount is too large, the fluidity of the silicone rubber composition decreases, and the desired cured product thickness cannot be obtained or the coating workability decreases. To do.

When hydrophilic fine powder silica is used, it is preferable to use the surface after hydrophobizing the surface with a hydrophobizing agent as necessary. Examples of the hydrophobizing agent include organosilazanes such as hexamethyldisilazane, halogenated silanes such as methyltrichlorosilane, dimethyldichlorosilane, and trimethylchlorosilane, and these halogen atoms are alkoxy groups such as methoxy group and ethoxy group. Examples thereof include substituted organoalkoxysilanes and dimethyl silicone oil, and hexamethyldisilazane is preferable.

(Ingredient (F))
Component (F) is a component that imparts a function of improving the strength of the cured product of the silicone rubber composition, and includes a siloxane unit having a vinyl group in the molecule and T siloxane represented by the formula R ¹ SiO _3/2. A unit (wherein R ¹ is the same or different from each other, an unsubstituted or substituted monovalent hydrocarbon group having 1 to 18 carbon atoms) and / or the formula SiO _4/2 Organopolysiloxane resins containing siloxane units having Q siloxane units are preferred. It is preferable that these contain 0.1-50 mass parts with respect to 100 mass parts of components (A). If the amount is 0.1 parts by mass or less, the effect of improving the adhesiveness is not observed, and if it is 50 parts by mass or more, the cured product becomes too hard, or tackiness appears on the surface of the cured product and blocking is not preferable.

(Ingredient (G))
The organosilicon compound of component (G) is a component that imparts a function of further improving the adhesion of the silicone rubber composition of the present invention, and has an epoxy group and a silicon atom-bonded alkoxy group in one molecule. Any organosilicon compound can be used as long as it is a compound, but an organosilicon compound having at least one epoxy group and at least two silicon-bonded alkoxy groups is preferred. Examples of such an epoxy group include silicon in the form of a glycidoxyalkyl group such as a glycidoxypropyl group, an epoxy-containing cyclohexylalkyl group such as a 2,3-epoxycyclohexylethyl group, and a 3,4-epoxycyclohexylethyl group. It is preferably bonded to an atom, and an epoxy group in one molecule containing 2 to 3 epoxy groups may be used. Examples of the silicon atom-bonded alkoxy group include a trialkylsilyl group such as a trimethylsilyl group, a triethylsilyl group, a methyldimethoxysilyl group, an ethyldimethoxysilyl group, a methyldiethoxysilyl group, and an ethyldiethoxysilyl group, and an alkyldialkoxysilyl group. Etc. are preferable. Further, as a functional group other than those described above, a functional group selected from an alkenyl group such as a vinyl group, a (meth) acryloxy group, and a hydrosilyl group (SiH group) may be used.

(Ingredient (H))
Component (H) is a component having a function as a condensation promoter for promoting adhesion, and a metal alkoxide, metal salt, and metal having an element selected from B, Al, Ti, and Zr as a metal atom One or more compounds selected from the group consisting of chelates. Examples of such organometallic compounds include boron condensation catalysts such as boron isopropoxide; organotitanium alkoxides such as tetraisopropyl titanate, tetranormal butyl titanate, tetra tertiary butyl titanate, tetraoctyl titanate, and tetrastearyl titanate; Organic titanium acylates such as titanium isostearate, diisopropoxy (acetylacetonate) titanium, diisopropoxy (ethylacetoacetate) titanium, tetraacetylacetonate titanium, titanium-1,3-propanedioxybis (ethylacetate) Titanium-based condensation promoters represented by organic titanium chelate compounds such as acetate); tetraisopropyl zirconate, tetranormal butyl zirconate, tetratertiary butyl zirconate , Organic zirconium alkoxides such as tetraoctyl zirconate and tetrastearyl zirconate, organic zirconium acylates such as zirconium isostearate, zirconium diisopropoxy (acetylacetonate), zirconium diisopropoxy (ethylacetoacetate), zirconium Organic zirconium chelate compounds such as tetraacetylacetonate, zirconium tributoxyacetylacetonate, zirconium butoxyacetylacetonate, zirconium bis (2-ethylhexanoate) oxide, zirconium acetylacetonate (2-ethylhexanoate) oxide, etc. Zirconium-based condensation promoters represented by oxozirconium compounds of the above; aluminum triethylate, aluminum Aluminum alkoxides such as umtriisopropylate and aluminum tri (sec-butyrate); aluminum chelate compounds such as diisopropoxyaluminum (ethyl acetoacetate) aluminum tris (ethyl acetoacetate) and aluminum tris (acetylacetonate); hydroxyaluminum bis An aluminum condensation catalyst represented by an aluminum acyloxy compound such as (2-ethylhexanoate) is exemplified.

(Component (I))
The component (I) may be any component as long as it imparts a function of further improving the dispersion of the block polyisocyanate composition of the component (B), but the density is 2.0 g / cm ^3. The above powder is preferable. When the oil absorption increases, the dispersion of the block polyisocyanate composition is further improved. Therefore, the amount is preferably 15 ml / 100 g or more, and the average particle diameter is preferably 100 μm or less for ease of blending. Specifically, powders such as precipitated barium sulfate and talc are exemplified.

In the silicone rubber composition of the present invention, any conventionally known additive as a silicone rubber can be used as an optional component other than the components (A) to (I) within the range not impairing the object of the present invention. Good. Such additives include viscosity modifiers, reinforcing fillers, non-reinforcing fillers, adhesion-imparting agents, pigments, dyes, cure inhibitors, heat-imparting agents, flame retardants, antistatic agents, conductivity-imparting agents, and airtightness. Containing a silicon atom-bonded hydrogen atom or alkenyl group in one molecule, and other properties improver, radiation shielding agent, electromagnetic shielding agent, preservative, stabilizer, organic solvent, plasticizer, fungicide, etc. Examples thereof include organopolysiloxanes that do not contain any functional group, non-functional organopolysiloxanes or organopolysiloxane resins that do not contain silicon-bonded hydrogen atoms or alkenyl groups. These may be used alone or in combination.

As the viscosity modifier, any material may be used as long as it imparts a function of controlling the viscosity change of the silicone rubber composition. Specifically, at least one silanol group (that is, one molecule) Silanes containing hydroxyl groups bonded to silicon atoms are preferred. These may be used alone or in plural, and specific examples include trimethylsilanol, triethylsilanol, triisopropylsilanol, triphenylsilanol, dimethylphenylsilanol, vinylphenylmethylsilanol, dimethylvinylsilanol, etc. In view of ease of treatment, trimethylsilanol, triethylsilanol, triisopropylsilanol, and triphenylsilanol are preferable.

As the adhesiveness imparting agent, a silane coupling agent not containing an epoxy group may be further blended. As the organic functional group, those containing one or more selected from vinyl group, methacryl group, acrylic group, and isocyanate group are preferable, and 3-methacryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane are preferable. And flange-on such as 3-trimethoxysilylpropyl succinic anhydride and dihydro-3- (3- (triethoxysilyl) propyl) -2,5-flange-on. The organic functional group may be bonded to the silicon atom via another group such as an alkylene group. These are particularly preferably used in combination with the component (H), and the effect thereof is further promoted, so that the combined use is preferable. Specifically, the titanium chelate compound is used in combination with the methacryloxy group-containing organoalkoxysilane, and / or zirconium. A chelate compound, and / or an aluminum chelate compound, or a titanium chelate compound for dihydro-3- (3- (triethoxysilyl) propyl) -2,5-furandone, and / or Examples include combinations of zirconium chelate compounds and / or aluminum chelate compounds.

Pigments include titanium oxide, alumina silicate, iron oxide, zinc oxide, carbon black, rare earth oxide, chromium oxide, cobalt pigment, ultramarine, cerium silanolate, aluminum oxide, aluminum hydroxide, titanium yellow, carbon black, phthalocyanine Examples are blue and a mixture thereof.

As the curing inhibitor, all conventionally known compounds having a curing inhibiting effect can be used, and phosphorus-containing compounds such as acetylene compounds, hydrazines, triazoles, phosphines, mercaptans, triphenylphosphine, Nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine and benzotriazole, sulfur-containing compounds, acetylene compounds, compounds containing two or more alkenyl groups, hydroperoxy compounds, maleic acid derivatives, silanes and silicone compounds having amino groups Etc. are exemplified.

More specifically, various “en-in” systems such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; Acetylene alcohols such as 1-hexyn-3-ol, 1-ethynyl-1-cyclohexanol, and 2-phenyl-3-butyn-2-ol; well known dialkyl, dialkenyl, and dialkoxyalkyl fumarate and maleate And maleate and fumarate, and those containing cyclovinylsiloxane.

Examples of the heat resistance-imparting agent include cerium hydroxide, cerium oxide, iron oxide, fume titanium dioxide, and a mixture thereof.

Examples of the flame retardant include metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide, diatomaceous earth, and calcium carbonate.

Any airtightness improver may be used as long as it has an effect of reducing the air permeability of the cured product, and any organic or inorganic material may be used. Specifically, polyvinyl alcohol, polyisobutylene, isobutylene-isoprene copolymer, powder having a flat shape such as mica, glass flakes, boehmite, various metal foils and metal oxides, silicone rubber powder and silicone resin Examples thereof include powders and mixtures thereof.

In order to produce the silicone rubber composition of the present invention, a method known to those skilled in the art can be used, and the method is not limited. For example, component (A), component (B), component (C), and component (E) are mixed in advance, or component (A), component (D), and component (E) are mixed with a stirrer, or 2 A silicone rubber base is prepared by uniformly kneading with a high-shear mixer such as a roll, a kneader mixer, a pressure kneader mixer, a loss mixer, an extruder, or a continuous extruder. You may mix and manufacture any of F)-component (I). Further, for example, a known method in which the component (A) and the component (C), or the component (A) and the component (D) are produced with an emulsifier using an emulsifier may be used. The silicone rubber composition of the present invention may be stored in an organic solvent such as toluene, xylene, hexane, white spirit, or a mixture thereof.

In particular, the present invention relates to a silicone rubber composition for a fiber base fabric used for an airbag of an automobile or the like. The airbag is obtained by stitching an airbag base cloth into a bag shape. This is a device that ensures the safety of the driver and passengers by expanding the bag at the time of collision. The airbag base fabric is usually a fabric in which synthetic fibers such as polyamide and polyethylene terephthalate are woven, and the silicone rubber composition of the present invention is coated on these synthetic fiber fabrics. Specifically, polyamide fiber fabric such as nylon 6, nylon 66, nylon 46, aramid fiber fabric, polyester fiber fabric represented by polyalkylene terephthalate, polyetherimide fiber fabric, sulfone fiber fabric, carbon fiber fabric, or Mixtures of these are used. The silicone rubber composition is coated on a woven fabric having a shape such as a plain weave, a bag shape, a hose shape, etc., using a yarn having a thickness of 10 to 5,000 dtex, but it is 50 to 50 from the viewpoint of workability and economy. A fabric using 1,000 dtex yarn is preferred.

The woven fabric may be either unscoured or scoured, but in the case of unscoured, the scouring step can be omitted by direct coating. The type and components of the oil agent are not particularly limited, but the amount of the oil agent is preferably 5% by mass or less, more preferably 3% by mass or less, based on the ease of production.

The silicone rubber composition of the present invention can be coated by a commonly used method, for example, dipping and padding, brush coating, flow coating, spraying, roller coating, gravure coating, comma A coater, textile printing, knife coating, Mayer bar, air brush, slop padding, roll coating, etc. are used, and coating is carried out alone or in combination depending on the situation. Further, the coating is not necessarily performed once, and may be performed a plurality of times until a desired coating state is obtained. Therefore, the cured film after coating may not necessarily be a single layer, and may be composed of a plurality of cured films. Furthermore, for the purpose of imparting effects such as antifouling, antistatic, slipperiness and antiblocking to the surface of the cured film after coating, the desired components can be added to the silicone rubber composition, Alternatively, the surface may be processed after curing, or a cured layer having such a function may be further formed.

Drying and curing after the coating is performed is usually done in a heating device that can be heated by hot air, infrared, near infrared, gas burner, heat exchanger or other energy source. In addition to a commonly used heating device, any device that can achieve the object can be used. For example, a heating roll calender, a heatable bonding press, a heatable corrugated press Or a high temperature contact roll, a hot air dryer, and a microwave dryer are illustrated.

At the time of curing, in order to avoid the formation of bubbles in the cured film, it is preferable to provide a plurality of temperature zones with different temperatures in the heating device, for example, 60 to 150 ° C., preferably 80 to 130 in the first temperature zone. Preliminary drying is performed at a temperature of 90 ° C., more preferably 90 to 120 ° C., and curing can be carried out at a temperature of 300 ° C. or less in the subsequent second and subsequent temperature zones, but many fibers are limited in heat resistance during processing. Therefore, the temperature is preferably 250 ° C. or lower.

Even when it is difficult to provide a plurality of temperature zones in the process, it is preferable to perform preliminary drying so that the base material to be cured reaches a temperature of at least 170 ° C. at least once. The residence time required for curing varies depending on the weight of the coating, the thermal conductivity of the fabric and the thermal conductivity of the coated fabric, etc., preferably about 0.5 to 30 minutes, If so, it may be carried out by standing for 10 minutes to several hours.

EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not limited to the following Example. In addition, all the compounding part numbers in each example show a mass part. The results of Examples and Comparative Examples are shown in Tables 1 and 2.

<Test fabric>
The base fabric is a plain woven fabric made of polyester composed of yarns having a thickness of 470 decitex, and a base fabric in which the amount of the oil agent is 0.04% by mass of the fabric weight by scouring, and the amount of the oil agent in the unscoured weight of the fabric weight Two types of base fabrics of 1.2% by mass were used.

<Coating method>
In order to confirm the time course of adhesiveness, the silicone rubber composition after the formulation was allowed to stand at room temperature for 5 hours or more before coating. Coating was performed using a knife coater, and curing was performed at a temperature of 190 ° C. and a curing time of 45 seconds.

<Coating adhesion test method>
The adhesion of the cured product was confirmed by a stagnation test. A coating cloth having a length of 10 cm and a width of 5 cm was prepared, and measurement was performed by applying a load of 10 N on the cured film. The test apparatus used was a scrub tester INC-1507-A (manufactured by Imoto Seisakusho Co., Ltd.), and the test was performed in accordance with ISO 5981.
The measurement was performed after the coated fabric was allowed to stand at room temperature for 24 hours, and the determination of adhesiveness was accepted when no pinhole or peeling was observed when the number of stagnation was 1000 times.

<Example 1>
As component (A-1), 6 parts of dimethylpolysiloxane containing both ends vinyl groups having a viscosity of about 20,000 mPa · s and 8 parts of dimethylpolysiloxane containing both ends vinyl groups having a viscosity of about 100,000 mPa · s And 7.8 parts of dimethylpolysiloxane containing vinyl groups at both ends having a viscosity of about 1,000 mPa · s, and dimethylpolysiloxane containing vinyl groups in both ends and molecules having a viscosity of about 10 mPa · s (vinyl group) Content 3 mmol / g) 0.5 part, and as component (B), 0.3 parts of Duranate X2252 (Asahi Kasei Co., Ltd.) having a viscosity of 20,000 mPa · s at 60 ° C., As component (C), a dimethylpolysiloxane solution containing 1% of platinum-divinyltetramethyldisiloxane complex as platinum content. A rubber base was prepared by adding 3 parts and mixing well with a stirring mixer.

Into 77 parts of the rubber base, 5.9 parts of fumed silica having a specific surface area of 300 m ² / g measured by the BET method and 0.1 part of ethynylcyclohexanol as a curing inhibitor are added as the component (E). And mixed well with a stirring mixer. Furthermore, as component (D), the viscosity at 25 ° C. is 30 mPa · s, both ends trimethylsiloxy group-blocked methyl hydrogen polysiloxane (hydrogen content 1.6%) 0.6 parts, and the viscosity at 25 ° C. is 70 mPa · 3 parts trimethylsiloxy group-capped methylhydrogenpolysiloxane (hydrogen content 0.8%) as s, and both ends trimethylsiloxy group-capped methylphenylhydrogenpolysiloxane with a viscosity at 25 ° C of 40 mPa · s (Hydrogen content 0.8%) 0.2 parts and organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms only at both ends of a molecular chain having a viscosity at 25 ° C. of 50 mPa · s (hydrogen content 0.05%) and 0.3 part of trimethylsilanol, and mix well with a stirring mixer. .

Furthermore, 0.8 parts of 3-glycidoxypropyltrimethoxysilane as component (G) and 0.5 parts of diisopropoxy (ethyl acetoacetate) titanium as component (H) were added, and the mixture was stirred. The silicone rubber composition of Example 1 was prepared by mixing well. The molar ratio of all Si—H groups to all vinyl groups in this silicone rubber composition was 5.9. This was allowed to stand at room temperature for 5 hours, then coated on a scoured polyester cloth at about 36 g / m ² and cured, and then allowed to stand at room temperature for 24 hours before performing an adhesion test.

In the coated fabric of Example 1, several pinholes were observed at 2,000 times, but there was no pinhole or peeling until 1,800 times, showing good adhesion, and the determination of adhesion was acceptable. there were.

<Example 2>
The silicone rubber composition of Example 1 that was allowed to stand at room temperature for 5 hours was coated on an unscoured polyester cloth at 36 g / m ² to prepare a coated cloth in the same manner as in Example 1. In Example 2, although the amount of the oil agent was increased, there was no pinhole or peeling up to 1,800 times, and the adhesion determination was acceptable.

<Example 3>
In addition to the formulation of the silicone rubber composition of Example 1, 6 parts of an organopolysiloxane resin having vinyl group units and Q siloxane units in the molecule as component (F), and precipitated barium sulfate as component (I) 0.3 parts of powder (density 4.0 g / cm ³ , oil absorption 18 ml / 100 g, average particle size 0.3 μm) was added and mixed well with a stirrer-mixer to prepare the silicone rubber composition of Example 3. This was allowed to stand at room temperature for 5 hours, then coated on an unscoured polyester cloth at about 35 g / m ² and cured to prepare a coated cloth. In Example 3, the adhesion was further improved, pinholes and peeling were not observed even after 2,000 times, and the adhesion determination was acceptable.

<Comparative Example 1>
A component not containing the block polyisocyanate composition as the component (B) of the formulation of Example 3 was prepared, and this was designated as Comparative Example 1. Then, it was coated at 35 g / m ² on a scoured polyester cloth that was allowed to stand at room temperature for 5 hours, and a coated cloth was produced in the same manner as in Example 1. In Comparative Example 1, pinholes and peeling were not observed up to 600 times, but the test was stopped because peeling was observed at 800 times. Therefore, the determination of adhesiveness was unacceptable.

<Comparative Example 2>
The preparation liquid prepared in Comparative Example 1 which was allowed to stand at room temperature for 5 hours was coated on an unscoured polyester cloth at 35 g / m ² to prepare a coated cloth in the same manner as in Example 1. In Comparative Example 2, pinholes and peeling were not observed up to 200 times, but the test was stopped because peeling was observed at 400 times. The determination of adhesiveness was unacceptable.

According to the present invention, the silicone rubber composition containing the block polyisocyanate composition and the curable silicone rubber composition has good compatibility between the block polyisocyanate composition and the curable silicone rubber composition, and the silicone rubber composition Adhesiveness does not decrease over time, and the silicone rubber composition is coated on a scoured or scoured woven fabric whose amount of oil is 5% by mass or less of the woven fabric weight and is strong even when cured. Therefore, the work load of the scouring process can be greatly reduced and the productivity can be improved.

Claims (13)

A silicone rubber composition comprising a block polyisocyanate composition and a curable silicone rubber composition, wherein the block polyisocyanate composition comprises a polyisocyanate and a heat dissociable blocking agent. Rubber composition. The block polyisocyanate composition contains a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of aliphatic diisocyanates and alicyclic diisocyanates, a thermally dissociable blocking agent, and substantially contains an organic solvent. The silicone rubber composition according to claim 1, wherein the silicone rubber composition has a viscosity at 60 ° C. of 100,000 mPa · s or less. A silicone rubber composition is applied to at least one surface of the fabric by coating and curing the silicone rubber composition on an unscoured or refined fabric having an oil amount of 5% by mass or less of the fabric weight. The silicone rubber composition according to claim 1, wherein a cured product layer of the product is formed. In the block polyisocyanate composition, at least one diisocyanate compound selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate is hexamethylene diisocyanate, and the thermally dissociable blocking agent is an oxime type, an acid amide type, The silicone rubber composition according to any one of claims 1 to 3, wherein the silicone rubber composition is at least one selected from amine-based, active methylene-based and pyrazole-based compounds. (A) (A-1) 100 parts by mass of an organopolysiloxane having an average of 1.8 or more alkenyl groups bonded to silicon atoms in one molecule, or
(A-2) 100 parts by mass of an organopolysiloxane having hydroxy groups bonded to silicon atoms at both ends of the molecular chain, and / or an organopolysiloxane having alkoxy groups bonded to silicon atoms at both ends of the molecular chain,
(B) A polyisocyanate obtained from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, a thermally dissociable blocking agent, substantially free of an organic solvent, and at 60 ° C. 0.01-5 parts by mass of a block polyisocyanate composition having a viscosity of 100,000 mPa · s or less,
(C) an effective amount of curing catalyst,
The silicone rubber composition according to claim 1, comprising: As component (D), an organohydrogenpolysiloxane having an average of two or more hydrogen atoms bonded to silicon atoms in one molecule was bonded to silicon atoms with respect to the alkenyl group of component (A-1). The hydrogen atom is contained in an amount of 0.5 to 20 mol, and the curing catalyst of component (C) is a catalyst that promotes an addition reaction between a Si—H group and a carbon-carbon unsaturated group. The silicone rubber composition according to any one of claims 1 to 5. The component (E) contains 0.5 to 50 parts by mass of finely divided silica having a specific surface area by a BET method of 50 m ² / g or more with respect to 100 parts by mass of the component (A). Item 7. The silicone rubber composition according to any one of Items 1 to 6. As the component (F), a siloxane unit having a vinyl group in the molecule and a T siloxane unit represented by the formula R ¹ SiO _3/2 (wherein R ¹ is the same or different from each other having 1 to 18 carbon atoms. And / or an organopolysiloxane resin containing a siloxane unit having a Q siloxane unit represented by the formula SiO _4/2 , wherein the component (A) is a non-substituted or substituted monovalent hydrocarbon group. The silicone rubber composition according to any one of claims 1 to 7, wherein the silicone rubber composition is contained in an amount of 0.1 to 50 parts by mass with respect to 100 parts by mass. The silicone rubber composition according to any one of claims 1 to 8, comprising an organosilicon compound having an epoxy group and a silicon-bonded alkoxy group in one molecule as the component (G). The component (H) includes one or more compounds selected from the group consisting of metal alkoxides, metal acid salts, and metal chelates, each having an element selected from B, Al, Ti, and Zr as a metal atom. The silicone rubber composition according to any one of claims 1 to 9. As component (I), it has a function of improving the dispersion of the block polyisocyanate composition of component (B), the density is 2.0 g / cm ³ or more, the oil absorption is 15 ml / 100 g or more, and the average particle size is 100 μm or less. The silicone rubber composition according to any one of claims 1 to 10, wherein the silicone rubber composition comprises: The silicone rubber composition according to any one of claims 1 to 11, wherein the silicone rubber composition is an unscoured or scoured fabric, and the amount of oil agent is 5% by mass or less of the fabric weight by coating and curing. A method for producing a coating material and a coating material obtained by forming a cured layer of a silicone rubber composition on at least one surface of the fabric. An airbag using the coating product according to claim 12.