Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
  • C08L83/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/12—Polysiloxanes containing silicon bound to hydrogen
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/14—Polysiloxanes containing silicon bound to oxygen-containing groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
  • C08G77/20—Polysiloxanes containing silicon bound to unsaturated aliphatic groups

Definitions

• the present invention relates to a silicone rubber composition containing a block polyisocyanate composition and a curable silicone rubber composition, a manufacturing method of a coated product, and a coated product.
• the compatibility between the block polyisocyanate composition and the curable silicone rubber composition is favorable, and the adhesion of the silicone rubber composition does not decrease as time passes.
• the present invention relates to a silicone rubber composition, a method for manufacturing a coated product, and a coated product, which are suitable for air bags.
• Patent Literature 1 discloses a method of limiting the component and amount of an oil
• composition in order to increase the adhesion force thereof.
• it is difficult to suppress the leakage of a high-pressure gas and maintain the persistence of expansion time. Therefore, strong adhesiveness is demanded in order to achieve the object. As such a
• Patent Literature 2 discloses an isocyanate compound.
• triallyl isocyanurate can exert the adhesion effect, and there is no description or knowledge regarding the refining state of a fabric and the oil solution. Since triallyl isocyanurate is solid, there has been the drawback that compatibility thereof with the silicone rubber composition is poor, causing difficulty in dispersion. As a result, due to separation and dispersion failure, the silicone rubber composition could not adhere to, in
• a fabric which is unrefined or not sufficiently refined to have a large amount of a remained oil solution As a method for improving compatibility, there is a means of adding an organic solvent.
• an organic solvent is not preferred, and it is required to contain a small amount of a solvent, more preferably to hardly contain a solvent.
• Non- Patent Literature 1 For controlling the reactivity of an isocyanate group, a low-viscosity block polyisocyanate composition not containing a solvent is disclosed in Non- Patent Literature 1. However, there is no description or knowledge regarding mixing such a low-viscosity block
• a known silicone rubber composition including a block polyisocyanate composition and a curable silicone rubber composition has a problem in terms that the compatibility between the block polyisocyanate composition and the curable silicone rubber composition is favorable, the adhesiveness of the silicone rubber composition does not decrease as time passes, and when the silicone rubber
• the silicone rubber composition is applied onto an unrefined or refined fabric in which the amount of an oil solution is 5% by mass or less relative to the weight of the fabric, the silicone rubber composition strongly adheres to the fabric even when cured. Therefore, a silicone rubber composition which can achieve the object has been demanded.
• Patent Literature 1 Japanese Patent Application Laid- Open No. 2012-177220
• Patent Literature 2 Japanese Patent Application Laid- Open No. 2007-186596
• Non-Patent Literature 1 "Technical data sheet (Coating
• the present invention has been achieved in view of the aforementioned problems, and relates to a silicone rubber composition containing a block polyisocyanate composition and a curable silicone rubber composition.
• An object of the present invention is to provide a silicone rubber composition in which the compatibility between the block polyisocyanate composition and the curable silicone rubber composition is favorable, and the adhesiveness of the silicone rubber composition does not decrease as time passes; and which, when it is applied onto an unrefined or refined fabric in which the amount of an oil solution is 5% by mass or less relative to the weight of the fabric, can strongly adhere to the fabric even when cured.
• the silicone rubber composition in which the compatibility between the block polyisocyanate composition and the curable silicone rubber composition is favorable, and the adhesiveness of the silicone rubber composition does not decrease as time passes; and which, when it is applied onto an unrefined or refined fabric in which the amount of an oil solution is 5% by mass or less relative to the weight of the fabric, can strongly adhere to the fabric even when cured.
• the silicone rubber composition in which
• composition is suitable for air bags. SOLUTION TO PROBLEM
• the present inventors have intensively conducted studies. As a result, they have found that the object of the present invention can be achieved by using a block polyisocyanate composition, in particular, which has a low viscosity. Thus, the present invention has been completed.
• the present invention provides a silicone rubber composition including a block polyisocyanate composition and a curable silicone rubber composition, wherein the block
• polyisocyanate composition contains a polyisocyanate and a thermally dissociating blocking agent.
• the compatibility According to the silicone rubber composition including a block polyisocyanate composition and a curable silicone rubber composition of the present invention, the compatibility
• the adhesiveness of the silicone rubber composition does not decrease as time passes. Furthermore, when the silicone rubber composition is applied onto an unrefined or refined fabric in which the amount of an oil solution is 5% by mass or less relative to the weight of the fabric, the composition strongly adheres to the fabric even when cured. Therefore, the workload in a refining process can be drastically reduced, thereby improving productivity.
• the curable silicone rubber composition according to the present invention includes one or more composition kits of a silicone rubber composition, and is not particularly limited as long as these composition kits are mixed to initiate a reaction for curing so that a cured product of the silicone rubber composition is finally obtained.
• a curing technique may include peroxide curing, condensation curing, addition curing, UV curing, and electron beam curing.
• Examples of a suitable curing method according to the present invention may include a method of crosslinking an Si-H group of an organohydrogenpolysiloxane to an organopolysiloxane having an alkenyl group bonded to a silicon atom in one molecule with an addition reaction catalyst or an organic peroxide, and a method of crosslinking an Si-H group of an organohydrogenpolysiloxane to an organopolysiloxane having a hydroxy group or an alkoxy group bonded to a silicon atom at both terminals in the molecular chain with a condensation reaction catalyst.
• Component (A) is the main component of the curable silicone rubber composition, and the main material of the silicone rubber composition for obtaining excellent rubber properties after curing.
• Component (A-l) is an
• organopolysiloxane containing in average 1.8 or more alkenyl groups bonded to a silicon atom in one molecule and the average composition formula thereof is usually represented by the following general formula (1) :
• R 2 ' s are each the same or different, unsubstituted or substituted, monovalent hydrocarbon group with 1 to 18 carbon atoms, and a is 1.7 to 2.1.
• At least two monovalent hydrocarbon groups are selected from an alkenyl group such as a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a hexenyl group, and a cyclohexenyl group.
• an alkenyl group such as a vinyl group, an allyl group, a propenyl group, an isopropenyl group, a butenyl group, an isobutenyl group, a hexenyl group, and a cyclohexenyl group.
• Other groups are a substituted or unsubstituted monovalent hydrocarbon group with 1 to 18 carbon atoms, and specifically selected from: an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a
• neopentyl group a hexyl group, a 2-ethylhexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and a dodecyl group; a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, a biphenyl group, and a naphthyl group; an aralkyl group such as a benzyl group, a phenylethyl group, a phenylpropyl group, and a methylbenzyl group; and a halogen-substituted alkyl group and a cyano-substituted alkyl group in which a portion or the
• a vinyl group is preferable as the at least two alkenyl groups required, and a methyl group, a phenyl group, and a 3 , 3 , 3-trifluoropropyl group are preferable as other groups.
• 70 mol% or more of all R 2 ' s is preferably a methyl group from the viewpoint of properties of a cured product and economic efficiency. Usually, those having a methyl group in an amount of 80 mol% or more of all R 2 ' s are used .
• the organopolysiloxane of the component (A-l) may be linear or branched.
• the molecular structure may include: a dimethylpolysiloxane in which both terminals of the molecular chain are blocked with a dimethylvinylsiloxy group; a dimethylsiloxane-methylphenylsiloxane copolymer in which both terminals of the molecular chain are blocked with a
• an organopolysiloxane obtained by substituting a portion or the entirety of methyl groups of each of these organopolysiloxanes with an alkyl group such as an ethyl group and a propyl group, an aryl group such as a phenyl group and a tolyl group, and an alkyl halide group such as a 3 , 3 , 3-trifluoropropyl group; and a mixture of two or more of these organopolysiloxanes.
• a linear radicalsiloxane obtained by substituting a portion or the entirety of methyl groups of each of these organopolysiloxanes with an alkyl group such as an ethyl group and a propyl group, an aryl group such as a phenyl group and a tolyl group, and an alkyl halide group such as a 3 , 3 , 3-trifluoropropyl group
• organopolysiloxane having a vinyl group at both terminals of the molecular chain is preferable in terms of availability.
• Component (A-2) is an organopolysiloxane having a hydroxy group bonded to a silicon atom at both terminals of the molecular chain, and/or an organopolysiloxane having an alkoxy group bonded to a silicon atom at both terminals of the molecular chain.
• These organopolysiloxanes may be liner or branched.
• the alkoxy group may include a methoxy group and an ethoxy group. Of these, a methoxy group is preferable from the viewpoint of reactivity.
• Groups other than the hydroxy group and the alkoxy group are preferably the same or different, unsubstituted or substituted, monovalent
• hydrocarbon groups with 1 to 18 carbon atoms and specifically selected from: an alkyl group such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a
• neopentyl group a hexyl group, a 2-ethylhexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and a dodecyl group; a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, and a cycloheptyl group; an aryl group such as a phenyl group, a tolyl group, a xylyl group, a biphenyl group, and a naphthyl group; an aralkyl group such as a benzyl group, a phenylethyl group, a phenylpropyl group, and a methylbenzyl group; and a halogen-substituted alkyl group and a cyano-substituted alkyl group in which a portion or the
• the viscosity at 25°C thereof is preferably 50 to 1,000,000 mPa-s, and more preferably 200 to 500, 000 mPa-s .
• the viscosity may be measured using a rotary viscometer and the like.
• a block polyisocyanate composition of component (B) is an essential component of the present invention for enabling strong adhesion of the silicone rubber composition to an unrefined or refined fabric containing an oil solution in an amount of 5% by mass or less relative to the weight of the fabric.
• a conventionally known block polyisocyanate compound includes as a raw material a polyisocyanate and a blocking agent which are reacted to generate a urethane group and a urea group. Since a strong intramolecular hydrogen bond in the urethane group and the urea group significantly increases viscosity, there has been the drawback that handling is not easy.
• a block polyisocyanate composition includes a polyisocyanate obtained from at least one diisocyanate selected from the group consisting of an aliphatic diisocyanate and an alicyclic diisocyanate, and a thermally dissociating blocking agent.
• the block polyisocyanate composition substantially contains no organic solvent, and has a low viscosity at 60°C of 100,000 mPa-s or less. The use of such a block polyisocyanate
• composition can drastically improve compatibility with a curable silicone rubber composition as compared to a
• the silicone rubber composition does not decrease as time passes. Furthermore, even when the silicone rubber composition is applied onto an unrefined or refined fabric containing an oil solution in an amount of 5% by mass or less relative to the weight of the fabric, the silicone rubber composition strongly adheres to the fabric.
• aliphatic diisocyanate examples include butane diisocyanate, pentane diisocyanate, hexamethylene
• hexamethylene diisocyanate is preferable from the viewpoint of industrial availability.
• One of these aliphatic diisocyanates may be used alone, or two or more thereof may also be used in combination.
• the alicyclic diisocyanate may include isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated
• isophorone diisocyanate isophorone diisocyanate.
• One of these alicyclic diisocyanates may be used alone, or two or more thereof may also be used in combination.
• One of the aliphatic diisocyanate and the alicyclic diisocyanate may be used alone, or two or more of the aliphatic diisocyanate and the alicyclic diisocyanate may also be used in combination.
• the blocking agent is not particularly limited, as long as it has thermally dissociating properties and does not impair the object of the invention.
• the blocking agent can protect an isocyanate group, prevent the deactivation of an isocyanate group caused by moisture and the like, and suppress the poisoning of a curing catalyst by an isocyanate group.
• the blocking agent can stabilize and maintain the isocyanate group even in the silicone composition.
• isocyanate group from which the blocking agent has been dissociated can immediately exert adhesion effect.
• the blocking agent to be used is preferably one or more selected from an oxime-based compound, an acid amide-based compound, an amine-based compound, an active methylene-based compound, and a pyrazole-based compound, for reasons of industrial availability.
• Examples thereof may include methyl ethyl ketoxime, acetoxime, methanol, ethanol, acetanilide, amide acetate, ⁇ -caprolactam, diphenylamine, aniline, ethylacetoacetate, 3-methylpyrazole, and 3 , 5-dimethylpyrazole .
• the block polyisocyanate composition according to the present invention substantially contains no organic solvent.
• substantially contains no organic solvent means that the content of an organic solvent in the block polyisocyanate composition is 5% by mass or less, and preferably 3% by mass or less, more preferably 1% by mass or less, from the viewpoint of reduction in a load on the
• the viscosity is preferably as low as possible for improving compatibility.
• the viscosity at 60°C is preferably 100,000 mPa-s or less from the viewpoint of facilitating handling, more preferably 30,000 mPa-s or less from the viewpoint of facilitating mixing.
• the viscosity may be measured using an E-type viscometer for not more than
• a rotor can be selected depending on the viscosity to be measured.
• the mixing amount of the component (B) relative to 100 parts by mass of the component (A) is preferably 0.01 to 5 parts by mass, and more preferably 0.02 to 3 parts by mass.
• the mixing amount is 0.01 parts or less, the ratio of an initially exposed isocyanate group increases, thereby deactivating the isocyanate group by moisture and the like. Therefore, effect of the adhesiveness is unlikely to be obtained.
• the amount of 5 parts by mass or more is not
• the curing catalyst according to the present invention is not particularly limited, as long as it is used for curing the curable silicone rubber composition.
• a catalyst used for an addition reaction there is used any catalyst known to those skilled in the art which promotes an addition curing reaction between an alkenyl group and a hydrogen atom bonded to a silicon atom.
• platinum group metal such as platinum, rhodium, palladium, osmium, iridium, and ruthenium
• a product obtained by fixing the platinum group metal to a particulate carrier material for example, activated carbon, aluminum oxide, and silicon oxide
• a platinum compound such as platinum halide, a platinum- olefin complex, a platinum-alcohol complex, a platinum- alcoholate complex, a platinum-vinylsiloxane complex,
• dicyclopentadiene-platinum dichloride dicyclopentadiene-platinum dichloride, cyclooctadiene-platinum dichloride, and cyclopentadiene-platinum dichloride.
• a metal compound catalyst other than noble metal may be used.
• Specific examples thereof may include a hydrosilylation iron catalyst such as an
• iron—carbonyl complex catalyst an iron catalyst having a cyclopentadienyl group as a ligand, an iron catalyst having a terpyridine-based ligand, or a terpyridine-based ligand and a bistrimethylsilylmethyl group, an iron catalyst having a bisiminopyridine ligand, an iron catalyst having
• bisiminoquinoline as a ligand an iron catalyst having an aryl group as a ligand, an iron catalyst having a cyclic or non- cyclic olefin group with an unsaturated group, and an iron catalyst having a cyclic or non-cyclic olefinyl group with an unsaturated group.
• Other examples may include a cobalt catalyst, a vanadium catalyst, a ruthenium catalyst, an iridium catalyst, a samarium catalyst, a nickel catalyst, and a manganese catalyst, which serve as a hydrosilylation
• the catalyst may be used in a form of being
• examples of a particulate solid which contains a catalyst and is insoluble in organopolysiloxane may include thermoplastic resin (for example, a polyester resin or a silicone resin) .
• the catalyst may also be used in a form of clathrate compound, for example, in cyclodextrins .
• the effective mixing amount of the catalyst depends desired curing temperature and curing time.
• the effective mixing amount of the catalyst relative to a total mass of the silicone rubber composition, in terms of the concentration of a catalyst metal element, may be usually 0.5 to 1,000 ppm, more preferably 1 to 500 ppm, and further preferably 1 to 100 ppm.
• the mixing amount thereof is less than 0.5 ppm, the curing becomes significantly slow or may be disabled.
• the mixing amount thereof is more than 1,000 ppm, costs increase, thereby unfavorably reducing economic efficiency.
• Examples of the catalyst used for a reaction by an organic peroxide may include benzoyl peroxide, 2,4- dichlorobenzoyl peroxide, p-chlorbenzoyl peroxide, o- chlorbenzoyl peroxide, p-methylbenzoyl peroxide, o- methylbenzoyl peroxide, 2,4-dicumyl peroxide, 2 , 5-dimethyl- bis (2 , 5-t-butylperoxy) hexane, di-t-butylperoxide, t- butylperbenzoate, and 1 , 1-bis (t-butylperoxycarboxy) hexane .
• the content of these organic peroxides relative to 100 parts by mass of the component (A-l) is 0.1 to 5 parts by mass.
• Examples of the catalyst used for a condensation reaction may include an organic tin-based catalyst such as dibutyltin diacetate, bis (acetoxydibutyltin) oxide,
• condensation reaction catalysts relative to 100 parts by mass of the component (A-2) is 0.1 to 20 parts by mass.
• Component (D) is an organohydrogenpolysiloxane having in average two or more hydrogen atoms bonded to a silicon atom in one molecule, and functions to react with the component (A) to serve as a crosslinking agent. Specific examples thereof may include methylhydrogenpolysiloxane, a dimethyl
• siloxane-methylhydrogenpolysiloxane copolymer a methyl phenyl siloxane-methylhydrogenpolysiloxane copolymer, cyclic
• the mixing amount of this organohydrogenpolysiloxane is preferably such that the amount of the hydrogen atom bonded to a silicon atom becomes 0.5 to 20 mol relative to a total of an alkenyl group of the component (A-l) .
• the mixing amount thereof is less than 0.5 mol, the hardness significantly decreases.
• the mixing amount thereof is more than 20 mol, the hardness becomes excessive, causing a cured coating film to unfavorably crack and peel.
• the viscosity at 25°C of the organohydrogenpolysiloxane of the component (D) is preferably 1 to 100,000 mPa-s, and more preferably 2 to 5, 000 mPa-s .
• One organohydrogenpolysiloxane of the component (D) may be used alone, or two or more thereof may also be used in combination.
• an organohydrogenpolysiloxane having a hydrogen atom bonded to a silicon atom only at both terminals of the molecular chain may be included for enhancing the elongation of a cured product of the silicone rubber
• composition to follow a stretchable fabric The
• organohydrogenpolysiloxane is preferably linear.
• the high elongation is likely to be obtained by relatively easily increasing the molecular chain length of the
• organopolysiloxane having an alkenyl group of the component (A-l) by a curing reaction.
• an organohydrogenpolysiloxane having a hydrogen atom at both terminals of the molecular chain and at any portion other than the both terminals may be included.
• Specific examples thereof may include a linear organohydrogenpolysiloxane represented by the following general formula (2) :
• R 3 ' s are independently the same or different, unsubstituted or halogen-substituted, monovalent hydrocarbon group with 1 to 10 carbon atoms which does not have an aliphatic unsaturated bond
• m is a positive number of 1 to 50
• n is 0 or a positive number of 1 to 150
• t indicated by formula: t m/ (m + n) satisfies 0.01 ⁇ t ⁇ 1.0.
• m is more preferably 1 to 20
• n is more preferably 10 to 100
• t is more preferably 0.02 ⁇ t ⁇ 1.0, further preferably 0.02 ⁇ t ⁇ 0.2.
• an organohydrogenpolysiloxane having a trimethylsiloxy group at both terminals of the molecular chain and at least one aromatic group in the molecule may be contained.
• the aromatic group is preferably a phenyl group for economic reasons.
• this organohydrogenpolysiloxane is used in combination with an organohydrogenpolysiloxane having a trimetylsyloxy group at both terminals of the molecular chain and not having an aromatic group in the molecule with a hydrogen content of 5 mmol/g or more, the adhesiveness is favorably further enhanced.
• a silica of component (E) is a component to serve as a reinforcing material. Examples thereof may include fumed silica, silica fume, precipitated silica, pyrogenic silica, colloidal silica, and diatomaceous earth, which have
• hydrophilicity or hydrophobicity are preferably micronized (micropowder) , and more preferably have a particle size of 100 ⁇ or less and a specific surface area of 50 m 2 /g or more, and further preferably 150 m 2 /g or more.
• organosilane, organosilazane, organocyclopolysiloxane, or the like may also be suitably used.
• (A) is usually 0.5 to 50 parts by mass, and preferably 1 to 30 parts by mass. One of these may be used alone, or two or more thereof may also be used in combination.
• the mixing amount of the component (E) is small, properties such as desired tear strength cannot be obtained.
• the mixing amount thereof is excessively large, the fluidity of the silicone rubber composition decreases. Accordingly, a desired thickness of a cured product cannot be obtained, and coating workability deteriorates.
• hydrophilic micronized silica When hydrophilic micronized silica is used, it is preferable that the surface of the micronized silica be previously subjected to hydrophobization treatment with a hydrophobization agent as necessary. Examples of the
• trichlorosilane dimethyl dichlorosilane, and trimethyl chlorosilane
• organoalkoxysilane in which the halogen atom of the aforementioned agents is substituted with an alkoxy group such as a methoxy group and an ethoxy group
• dimethyl silicone oil e.g., hexamethyl disilazane is
• Component (F) is a component to impart a function of improving the strength of a cured product of the silicone rubber composition, and preferably an organopolysiloxane resin containing in the molecule a siloxane unit having a vinyl group, and a siloxane unit having a T siloxane unit
• the content of the component (F) relative to 100 parts by mass of the component (A) is preferably 0.1 to 50 parts by mass. When the content thereof is 0.1 parts by mass or less, adhesiveness is not improved as expected. When the content thereof is 50 parts by mass or more, a cured product becomes excessively hard, or tack properties are exerted on the surface of a cured product, resulting in likeliness of blocking.
• An organosilicon compound of component (G) is a component to impart a function of further improving the adhesiveness of the silicone rubber composition according to the present invention, and may be any organosilicon compound as long as the compound has an epoxy group and a silicon atom-bonded alkoxy group in one molecule.
• an organosilicon compound having at least one epoxy group and at least two alkoxy groups bonded to a silicon atom is preferable.
• Such an epoxy group is preferably bonded to a silicon atom, in a form of a glycidoxyalkyl group such as a glycidoxypropyl group, and an epoxy-containing cyclohexylalkyl group such as a 2,3- epoxycyclohexylethyl group and a 3, 4-epoxycyclohexylethyl group.
• 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.
• Two or three epoxy groups may also be contained in one molecule.
• Examples of the silicon atom-bonded alkoxy group may include a trialkylsilyl group, an alkyldialkoxysilyl group, and the like, such as a trimethylsilyl group, a triethylsilyl group, a methyldimethoxysilyl group, an ethyldimethoxysilyl group, a methyldiethoxysilyl group, and an ethyldiethoxysilyl group.
• a functional group to be used other than the above- described groups 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.
• Component (H) is a component having a function as a condensation co-catalyst for promoting adhesion, and one or more compounds selected from the group consisting of a metal alkoxide, a metal acid salt, and a metal chelate, which include as a metal atom an element selected from B, Al, Ti, and Zr.
• organometallic compound may include a boron-based condensation catalyst such as boron isopropoxide ; a titanium-based condensation co-catalyst represented by, for example, an organic titanium alkoxide such as tetraisopropyl titanate, tetranormalbutyl titanate,
• tetrastearyl titanate an organic titanium acylate such as titanium isostearate, and an organic titanium chelate compound such as diisopropoxy (acetylacetonate) titanium,
• a zirconium-based condensation co-catalyst represented by, for example, an organic zirconium alkoxide such as tetraisopropyl zirconate, tetranormalbutyl zirconate, tetratertiarybutyl zirconate, tetraoctyl zirconate, and tetrastearyl zirconate, an organic zirconium acylate such as zirconium isostearate, an organic zirconium chelate compound such as zirconium
• an oxozirconium compound such as zirconium bis (2-ethylhexanoate) oxide and zirconium acetylacetonate (2-ethylhexanoate) oxide
• an aluminum-based condensation catalyst represented by, for example, an aluminum alkoxide such as aluminum triethylate, aluminum
• Component (I) is not particularly limited as long as it is a component to impart a function of further improving the dispersion of the block polyisocyanate composition of the component (B) , and is preferably a powder having a density of 2.0 g/cm 3 or more. Since a larger oil absorption amount improves the dispersion of the block polyisocyanate composition, the oil absorption amount is preferably 15 ml/100 g or more. Also, for facilitating mixing, the average particle size is preferably 100 ⁇ or less. Specific examples thereof may include a powder such as precipitated barium sulfate and talc.
• the silicone rubber composition according to the present invention may contain any additive that is publicly known as an additive for silicone rubber as an optional component other than the above-described components (A) to (I), within the range that does not impair the object of the present
• Examples of such an additive may include a
• viscosity modifier a reinforcing filler, a non-reinforcing filler, an adhesion-imparting agent, a pigment, a dye, a curing inhibitor, a heat resistance-imparting agent, a flame retardant, an antistatic agent, a conductivity-imparting agent, an airtightness improver, a radiation shielding agent, an electromagnetic wave shielding agent, a preservative, a stabilizer, an organic solvent, a plasticizer, a fungicide, an organopolysiloxane containing one silicon atom-bonded hydrogen atom or one alkenyl group in one molecule and not containing any other functional group, and a non-functional
• organopolysiloxane and an organopolysiloxane resin which do not contain a silicon atom-bonded hydrogen atom or an alkenyl group One of these may be used alone, or two or more thereof may also be used in combination.
• the viscosity modifier is not particularly limited, as long as it imparts a function of controlling a change in the viscosity of the silicone rubber composition.
• silanes containing at least one silanol group that is, a hydroxyl group bonded to a silicon atom
• One of these may be used alone, or two or more thereof may also be used in combination.
• Specific examples may include trimethyl silanol, triethyl silanol, triisopropyl silanol, triphenyl silanol, dimethyl phenyl silanol, vinyl phenyl methyl silanol, and dimethyl vinyl silanol.
• trimethyl silanol, triethyl silanol, triisopropyl silanol, and triphenyl silanol are preferable.
• a silane-coupling agent not containing an epoxy group may be further mixed.
• At least one selected from a vinyl group, a methacryl group, an acryl group, and an isocyanate group is preferably contained as an organic functional group.
• examples thereof may include a methacryloxysilane such as 3- methacryloxypropyltrimethoxysilane and 3- methacryloxypropyltriethoxysilane, 3-trimethoxysilylpropyl succinic acid anhydride, and a furandione such as dihydro-3- (3- (triethoxysilyl) propyl) -2, 5-furandione .
• the organic functional group may be bonded to a silicon atom via another group such as an alkylene group. These are particularly preferably used in combination with the component (H) because the effect is further promoted. Specific examples of such a combination may include a combination of a methacryloxy group- containing organoalkoxysilane and a titanium chelate compound, a combination of a methacryloxy group-containing
• organoalkoxysilane and a zirconium chelate compound a zirconium chelate compound
• organoalkoxysilane and an aluminum chelate compound a
• the pigment may include titanium oxide, alumina silicic acid, iron oxide, zinc oxide, carbon black, rare earth oxides, chromium oxide, cobalt pigment, ultramarine blue, cerium silanolate, aluminum oxide, aluminum hydroxide, titanium yellow, carbon black, phthalocyanine blue, and mixtures thereof.
• any compound which is publicly known as a compound having the curing inhibiting effect may be used.
• examples thereof may include an acetylene-based compound having the curing inhibiting effect.
• tetramethylethylenediamine and benzotriazole, a sulfur- containing compound, an acetylene-based compound, a compound having two or more alkenyl groups, a hydroperoxy compound, a maleic acid derivative, and silane and a silicone compound which have an amino group.
• Further specific examples may include various "ene-yne” systems such as 3-methyl-3-pentene-l-yne and 3 , 5-dimethyl-3- hexene-l-yne; acetylene-based alcohols such as 3, 5-dimethyl-l- hexyne-3-ol, 1-ethynyl-l-cyclohexanol, and 2-phenyl-3-butyne- 2-ol; known dialkyl, dialkenyl, and maleate and fumarate such as dialkoxyalkyl maleate and fumarate; and a substance
• heat resistance-imparting agent examples include cerium hydroxide, cerium oxide, iron oxide, fume titanium dioxide, and mixtures thereof.
• Examples of the flame retardant may include metal hydroxide such as aluminum hydroxide, magnesium hydroxide, and calcium hydroxide, diatomaceous earth, and calcium carbonate.
• the airtightness improver is not particularly limited as long as it has the effect of reducing the air permeability of a cured product, and can be either an organic substance or inorganic substance. Specific examples thereof may include polyvinyl alcohol, polyisobutylene, an isobutylene-isoprene copolymer, a flat-shaped powder such as mica, glass flake, boehmite, and various metal foils and metal oxides, a silicone rubber powder and a silicone resin powder, and mixtures thereof .
• composition according to the present invention is not
• the component (A), the component (B) , the component (C) , and the component (E) , or the component (A) , the component (D) , and the component (E) may be previously mixed using a stirrer, or uniformly kneaded using a two-roll, a kneader mixer, a pressure kneader mixer, a high shear-type mixer such as a Ross mixer, an extruder, a continuous extruder, and the like, to prepare a silicone rubber base. After that, to the obtained silicone rubber base, any of the component (F) to the component (I) may be added to manufacture the silicone rubber composition.
• the components (A) and (C) or the components (A) and (D) may be previously manufactured with an emulsifier using an
• the silicone rubber composition according to the present invention may be
• organic solvent such as toluene, xylene, hexane, white spirit, or a mixture thereof.
• the present invention particularly relates to a silicone rubber composition for fiber base cloths used for airbags of automobiles and the like.
• An airbag is obtained by sewing an airbag base cloth into a bag shape, and mainly mounted to automobiles.
• the bag is a device to be inflated in a collision to secure the safety of a driver and a passenger.
• An airbag base cloth is usually a fabric woven with synthetic fiber such as polyamide and polyethylene terephthalate.
• the silicone rubber composition according to the present invention is applied onto the synthetic fiber fabric.
• synthetic fiber fabric may include polyamide fiber fabric such as nylon 6, nylon 66, and nylon 46, aramid fiber fabric, polyester fiber fabric represented by
• the silicone rubber composition is applied onto a fabric woven with a thread having a size of 10 to 5,000 decitex and having a shape of flat woven, a bag, a hose, and the like. From the viewpoint of processability and economic efficiency, a fabric woven with a thread having a size of 50 to 1,000 decitex is preferable.
• the fabric may be used in an unrefined or refined state. When in an unrefined state, the fabric may be directly coated, thereby omitting a refining process.
• the type and component of the oil solution is not particularly limited. However, from the viewpoint of facilitating the manufacture, the amount of the oil solution relative to the weight of the fabric is preferably 5% by mass or less, and more preferably 3% by mass or less.
• Coating with the silicone rubber composition according to the present invention may be performed by a generally used method. Examples thereof may include immersion and padding, brushing, flow coating, spraying, roller coating, gravure coating, comma coater, fiber printing, knife coating, Meyer bar, air brush, slop padding, and roll coating. One or a combination of these methods may be performed depending on the circumstances. The coating is not necessarily performed once, and may be repeated multiple times until an intended coating state is obtained. Therefore, the number of cured films after coating is not necessarily one, and may be two or more.
• an additional intended component may be mixed into the silicone rubber composition, the surface after coating or curing may be processed, or a cured layer having such a function may be further formed.
• the drying and curing after coating are usually performed in a heating device which can generate heat with an energy source such as hot air, infrared ray, near-infrared ray, a gas burner, and a heat exchanger.
• an energy source such as hot air, infrared ray, near-infrared ray, a gas burner, and a heat exchanger.
• any heating device capable of achieving an intended purpose may be used. Examples thereof may include a heating roll calendar, a heatable bonding press, a heatable daylight press, a high-temperature kiss roll, a hot air dryer, and a microwave dryer.
• a heating device During curing, it is preferable to set a plurality of temperature zones with different temperatures to a heating device, in order to prevent the formation of bubbles in a cured film. For example, in a first temperature zone,
• preliminary drying may be performed at a temperature of 60 to 150°C, preferably 80 to 130°C, and further preferably 90 to 120°C, and in a subsequent second temperature zone, curing may be performed at a temperature of 300°C or lower.
• 300°C or lower since most fibers have heat resistance limitation in terms of processing, 250°C or lower is preferable.
• preliminary drying be performed such that the temperature of a base material to be cured reaches 170°C or higher at least once.
• the retention time necessary for curing varies depending on the weight of coating, the thermal conductivity of a fabric and a coated fabric, and the like. However, it is preferably about 0.5 to 30 minutes. At room temperature, a base material may be left to stand for 10 minutes to several hours.
• Two polyester plain-woven cloths formed of a 470-decitex thread were used as a test base cloth.
• One is a base cloth having been refined thereby to adjust an oil solution amount to 0.04% by mass relative to a fabric weight, and the other is a base cloth not having been refined and having an oil
• the coating was performed with a knife coater.
• the curing temperature was 190°C, and the curing time was 45 seconds .
• the adhesiveness of the cured product was confirmed in a crease-flex test.
• the measurement was performed by preparing a coated cloth with a size of 10 cm in length x 5 cm in width, and applying a load of 10 N onto the cured film.
• the test device used was an INC-1507-A scrub tester (manufactured by Imoto Machinery Co Ltd.), and the test was performed in accordance with ISO 5981.
• the component (A-l) was obtained by mixing 8 parts of a dimethylpolysiloxane containing a vinyl group at both
• component (A-l) To the component (A-l), there were added 0.3 parts of Duranate X2252 (manufactured by Asahi Kasei Corp.), as the component (B) , having a viscosity at 60°C of 20, 000 mPa-s, and 0.3 parts of a dimethylpolysiloxane solution, as the component (C) ,
• component (D) 0.6 parts of a methylhydrogenpolysiloxane (hydrogen content: 1.6%) in which both terminals were blocked with a trimethylsiloxy group, and the viscosity at 25°C was 30 mPa-s, 3 parts of a methylhydrogenpolysiloxane (hydrogen content: 0.8%) in which both terminals were blocked with a trimethylsiloxy group, and the viscosity at 25°C was 70 mPa-s, 0.2 parts of a methylphenylhydrogenpolysiloxane (hydrogen content: 0.8%) in which both terminals were blocked with a trimethylsiloxy group, and the viscosity at 25°C was 40 mPa-s, 5 parts of an organohydrogenpolysiloxane (hydrogen content: 0.05%) in which only both terminals have a hydrogen atom bonded to a silicon atom, and the viscosity at
• the coated cloth of Example 1 had several pinholes at 2,000 times. However, it had no pinholes and peeling until 1,800 times, and exhibited favorable adhesiveness with the judgment of adhesiveness being success.
• Example 1 The silicone rubber composition in Example 1 having been left to stand at room temperature for 5 hours was applied onto an unrefined polyester cloth with 36 g/m 2 to prepare a coated cloth in the same manner as that in Example 1. Even with the cloth of Example 2 having an increased amount of an oil solution, pinholes and peeling were not observed until 1,800 times with the judgment of adhesiveness being success.
• a silicone rubber composition of Example 3 was prepared by: further adding, to the formulation of the silicone rubber composition of Example 1, 6 parts of an organopolysiloxane resin having a vinyl group unit and a Q siloxane unit in the molecule as Component (F) , and 0.3 parts of a precipitated barium sulfate powder (density: 4.0 g/cm 3 , oil absorption: 18 ml/100 g, average particle size: 0.3 ⁇ ) as Component (I); and thoroughly mixing the mixture using a stirring and mixing device.
• the obtained silicon rubber composition was left to stand at room temperature for 5 hours, and applied onto a refined or unrefined polyester cloth with about 35 g/m 2 .
• the coating was cured to prepare a coated cloth.
• adhesiveness was further improved. Pinholes and peeling were not observed even at 2,000 times, and the judgment of
• a silicone rubber composition which did not include a block polyisocyanate composition as the component (B) in the formulation of Example 3 was prepared as Comparative Example 1. Then, the silicone rubber composition having been left to stand at room temperature for 5 hours was applied onto a refined polyester cloth with 35 g/m 2 to prepare a coated cloth in the same manner as that in Example 1.
• Comparative Example 1 A silicone rubber composition which did not include a block polyisocyanate composition as the component (B) in the formulation of Example 3 was prepared as Comparative Example 1. Then, the silicone rubber composition having been left to stand at room temperature for 5 hours was applied onto a refined polyester cloth with 35 g/m 2 to prepare a coated cloth in the same manner as that in Example 1. In Comparative Example 1.
• Example 1 pinholes and peeling were not observed until 600 times. However, since peeling was found at 800 times, the test was stopped. Accordingly, the judgment of adhesiveness was failure .
• the mixed liquid prepared in Comparative Example 1 having been left to stand at room temperature for 5 hours was applied onto an unrefined polyester cloth with 35 g/m 2 to prepare a coated cloth in the same manner as that in Example 1.
• the compatibility between the block polyisocyanate composition and the curable silicone rubber composition becomes favorable, and the
• the adhesiveness of the silicone rubber composition does not decrease as time passes. Furthermore, when the silicone rubber composition is applied onto an unrefined or refined fabric in which the amount of an oil solution is 5% by mass or less relative to the weight of the fabric, it strongly adheres to the fabric even when cured. Therefore, the work load in a refining process can be drastically reduced, thereby improving productivity.

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• Organic Chemistry (AREA)
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• 2017
  • 2017-06-28 JP JP2017126224A patent/JP6877837B2/ja active Active
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