JP2012158701A - Room temperature curable organopolysiloxane composition and silicone rubber molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a room temperature curable organopolysiloxane composition for coating which prevents dust and fins and foreign matter on molding from attaching due to the surface slip characteristics of the obtained cured coating film and, due to the high elongation of the obtained cured coating film, does not cause a fracture and a crack on deformation of an article when coated on the surface of the article such as a molded article, a gasket, and packing and a silicone rubber molded article whose surface is covered with a coating film obtained by curing the composition.SOLUTION: The condensed curable organopolysiloxane composition has a condensation reaction product of an organopolysiloxane having a three dimensional network comprising an RSiOunit (wherein R is independently a nonsubstituted or substituted 1-6C monovalent hydrocarbon group) and an SiOunit and a high-molecular weight straight-chain diorganopolysiloxane with both the molecular chain terminals blocked with hydroxyl groups as a base.

Description

  The present invention relates to a room temperature-curable organopolysiloxane composition that provides a coating film having slipperiness on the surface, and in particular, prevents the adhesion of dust, burrs during molding, and foreign matter by coating on the surface of a silicone rubber molded product. A room temperature-curable organopolysiloxane composition that can provide slipperiness and that follows well when a molded product is deformed, and that gives a cured coating film that does not crack or crack on the surface and has good adhesion, and the composition The present invention relates to a silicone rubber molded article whose surface is coated with a coating film obtained by curing the above.

Conventionally, several proposals have been made for methods for improving the surface tack of silicone rubber molded products.
Japanese Patent Application Laid-Open No. 2008-195939 (Patent Document 1) discloses a highly crosslinked addition-vulcanized silicone to which a diorganopolysiloxane having no alkenyl group and having a viscosity at 25 ° C. of at least 5,000,000 mPa · s is added. Compositions have been proposed. Although the composition gives a molded product having a low coefficient of friction, no mention is made of a coating that improves the surface tack of a conventional silicone rubber composition. Further, since the composition is an addition vulcanization type, its properties cannot be exhibited by room temperature curing, and complicated steps such as coating, heat curing, and cooling are required. Further, in the case of a silicone rubber molded product integrally molded with a resin base material, deterioration of the resin due to heat becomes a problem. In addition, in thin film coating, there is a high possibility of poor curing and surface stickiness due to the effects of added poisons derived from molded products and the environment.

  Silicone varnish coating is the most common method for improving the surface tack of molded articles, but the coating surface gives a glossy appearance and its slipperiness is not sufficient. Further, since the silicone varnish has almost no elongation, it cannot follow the deformation and elongation of the molded product, gasket, and packing, resulting in surface cracks, cracks, and the like. Japanese Patent Application Laid-Open Publication No. 2010-1000066 (Patent Document 2) proposes a coating film having surface slipperiness in which a small amount of dimethylpolysiloxane is added to a phenyl block polymer, but similarly cracks and cracks occur.

  Japanese Patent Application Laid-Open No. 6-248186 (Patent Document 3) proposes that an organic titanium compound is added to a phenyl block polymer to form a cured product having protrusions formed on the surface, thereby providing a coating film having antistatic properties. However, it will also crack and crack as well.

In Japanese Patent Application Laid-Open No. 2004-143331 (Patent Document 4), R ₃ SiO _1/2 unit (wherein R independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms) and There has been proposed a condensation curable composition based on a condensate of an organosiloxane composed of SiO _4/2 units and a diorganopolysiloxane whose molecular chain end is blocked with a functional group-containing silyl group. However, although a high-strength, high-elongation coating film can be obtained, surface slipperiness is not exhibited. By adding a siloxane having a bleeding property that does not dissolve in dimethylsiloxane, such as a phenyl group or a polyoxyalkylene structure, the ability to prevent biological adhesion can be obtained, but dust, burrs at the time of molding, and foreign matters are more likely to adhere.

  Further, in the composition of Japanese Patent Application Laid-Open No. 2004-143331, surface unevenness is imparted by adding fillers such as wet silica and dry silica in place of the bleed component, surface hardening by adding phenyl block polymer, and surface unevenness by adding titanate ester. However, in all cases, surface slipperiness was not obtained, but defects such as surface adhesion and cracking were generated.

JP 2008-195939 A JP 2010-1000066 A JP-A-6-248186 JP 2004-143331 A

  The present invention has been made in view of the above circumstances, and since the obtained cured coating film has surface slipperiness, it prevents dust, burrs during molding, and adhesion of foreign substances, and the resulting cured coating film has high elongation. Therefore, it is obtained by curing a room temperature curable organopolysiloxane composition for coating that does not crack or crack when the article is deformed even if applied to the surface of the article, such as a molded article, gasket, or packing, and cured. An object is to provide a silicone rubber molded article whose surface is coated with a coating film.

The present inventor previously described R ₃ SiO _1/2 unit in Japanese Patent Application No. 2010-192359 (wherein R independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms). And a condensation curable composition based on a condensate of an organosiloxane composed of SiO _4/2 units and a linear diorganopolysiloxane having a degree of polymerization of 1,000 or less in which both ends of the molecular chain are blocked with hydroxyl groups, A condensation curable composition was proposed in which diorganopolysiloxane raw rubber having a degree of polymerization of 5,000 or more was further added. In this invention, since the cured coating film obtained has surface slipperiness, it prevents dust, burrs at the time of molding and adhesion of foreign substances, and the cured coating film obtained has elongation, so that articles such as molded products, gaskets, packings, etc. A room temperature curable organopolysiloxane composition for coating that does not crack or crack when deformed, even if applied to the surface and cured, and a silicone rubber molding whose surface is coated with a coating film obtained by curing the composition Offering goods. However, cracks and cracks are judged by visually observing the surface when 100% stretched, and no cracks or cracks during further high deformation of 200% or more have been confirmed.

As a result of further intensive studies, the present inventor has found that R ₃ SiO _1/2 units (wherein R independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms) and SiO _{4 /} Condensation-curable organopolysiloxanes based on condensation reaction products of _2- unit organopolysiloxanes with a three-dimensional network structure and high-molecular-weight linear diorganopolysiloxanes having both molecular ends blocked with hydroxy groups Since the siloxane composition has a high molecular weight (high polymerization degree) without adding a diorganopolysiloxane raw rubber, the surface slipperiness of the cured coating is dramatically improved, and the cured coating has a high elongation. The inventors have found that neither cracking nor cracking occurs, and have studied the amount and type of addition, and have completed the present invention.

Accordingly, the present invention provides the room temperature curable organopolysiloxane composition and silicone rubber molded article shown below.
[Claim 1]
(I) Organo, which is a condensation reaction product of 80 to 20 parts by mass of the following component (A) and 20 to 80 parts by mass of component (B) (the total of components (A) and (B) is 100 parts by mass) Polysiloxane: 100 parts by mass,
(A) R ₃ SiO _1/2 unit (wherein R independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms) and a SiO _4/2 unit, and SiO _{4 / The} number of moles of R ₃ SiO _1/2 units per mole of ₂ units is 0.6 to 1.2 moles, and further R ₂ SiO _2/2 units and RSiO _3/2 units (wherein R is Can be contained in an amount of 0 to 1.0 mol per mol of SiO _4/2 units, and 0.02 to 0.12 mol / 100 g of hydroxy groups bonded to silicon atoms. Siloxane (B) Diorganopolysiloxane raw rubber having a hydroxy group at both ends and a polymerization degree of 5,000 or more (II) Organosilane compound having two or more hydrolyzable groups in one molecule bonded to a silicon atom and / or The partial hydrolysis condensate: 10-50 mass ,
(III) Solvent: A room temperature-curable organopolysiloxane composition containing 500 to 1,500 parts by mass.
[Claim 2]
The component (B) is represented by the following general formula (1):
HO— (R ¹ ₂ SiO) _n —H (1)
(In the formula, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n is an integer of 5,000 or more.)
The composition according to claim 1, which is a linear diorganopolysiloxane represented by the formula:
[Claim 3]
The component (II) is an organosilane compound having two or more hydrolyzable groups bonded to a silicon atom represented by the following general formula (2) and / or a partial hydrolysis condensate thereof. The composition according to 1 or 2.
R ² _a SiX _4-a (2)
(In the formula, R ² is an unsubstituted or substituted monovalent hydrocarbon group, X is a hydrolyzable group, and a represents 0, 1 or 2.)
[Claim 4]
The composition according to claim 1, 2 or 3, wherein the hydrolyzable group of the component (II) is a dialkyl ketoxime group.
[Claim 5]
A silicone rubber molded article having a surface coated with a coating film obtained by curing the composition according to any one of claims 1 to 4.

  According to the present invention, the obtained cured coating film has surface slipperiness, so that dust, burrs at the time of molding, and adhesion of foreign substances are prevented, and the obtained cured coating film has a high elongation. Even when applied to the surface of an article such as packing and cured, a room temperature-curable organopolysiloxane composition that does not crack or cause cracks when the article is deformed can be obtained.

Hereinafter, the present invention will be described in detail.
[(I) component]
Organopolysiloxane which is component (I) of the composition of the present invention is a base polymer (main agent) of the present composition, and is a condensation reaction product of component (A) and component (B) described later.

<(A) component>
The component (A) consists of R ₃ SiO _1/2 units (wherein R independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms) and SiO _4/2 units, The number of moles of R ₃ SiO _1/2 units per mole of SiO _4/2 units is 0.6 to 1.2 moles, and R ₂ SiO _2/2 units and RSiO _3/2 units (in the above formulas, R is as described above) may be contained in an amount of 0 to 1.0 mol per mol of SiO _4/2 units, and 0.02 to 0.12 mol / 100 g of hydroxy groups bonded to silicon atoms. It is an organopolysiloxane having a three-dimensional network (resinous) structure.

  Examples of R include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl; cyclopentyl, cyclohexyl, etc. A cycloalkyl group; an alkenyl group such as a vinyl group, an allyl group, an isopropenyl group, a butenyl group, a pentenyl group, and a hexenyl group; an aryl group such as a phenyl group; a chloromethyl group, a 3-chloropropyl group, and a 1-chloro-2 -Halogenated alkyl groups such as methylpropyl group and 3,3,3-trifluoropropyl group, etc. are mentioned, among which methyl group, vinyl group and phenyl group are preferable, and methyl group is particularly preferable.

The organopolysiloxane itself as the component (A) can be obtained by co-hydrolyzing and condensing an alkoxy group-containing silane compound corresponding to each unit in an organic solvent by a known method. For example, R ₃ SiOMe and Si (OMe) ₄ may be co-hydrolyzed in an organic solvent together with R ₂ Si (OMe) ₂ and / or RSi (OMe) ₃ and condensed if desired (note that In the above formulas, R is independently as described above, and Me represents a methyl group).

  As said organic solvent, what can melt | dissolve organopolysiloxane produced | generated by cohydrolysis and condensation reaction is preferable, and toluene, xylene, a naphtha mineral spirit etc. can be mentioned typically.

  About the content molar ratio of each unit which concerns on the said (A) component, it can set suitably by adjusting the preparation molar ratio of the silane compound corresponding to each unit, for example.

The number of moles of the R ₃ SiO _1/2 unit relative to 1 mole of SiO _4/2 units in the component (A) must be in the range of 0.6 to 1.2 moles, preferably 0.65 to 1. The range is 15 moles. If the number of moles is less than 0.6 moles, the strength of the cured product obtained from the composition of the present invention will be insufficient, and if it exceeds 1.2 moles, the transparency will be poor.

Further, if desired, the content of the R ₂ SiO _2/2 unit and RSiO _3/2 unit which may be contained in the component (A) is 1.0 mol per mol of SiO _4/2 unit. The following (that is, 0 to 1.0 mol), preferably 0.2 to 0.8 mol. When either one or both of the above contents exceeds 1.0 mol, the transparency becomes inferior.

  When the component (A) is prepared by a cohydrolysis / condensation reaction, a hydroxy group bonded to a silicon atom is generated. Containing this hydroxy group is required for the condensation reaction with the component (B), but the content in the component (A) needs to be 0.02 to 0.12 mol / 100 g. Yes, particularly preferably 0.03 to 0.10 mol / 100 g. The hydroxy group content can be set by adjusting cohydrolysis / condensation reaction conditions. When the content exceeds 0.12 mol / 100 g, the hardness of the cured product obtained from the composition of the present invention becomes too high, and rubber elasticity is impaired. Moreover, if it is less than 0.02 mol / 100g, the intensity | strength of the hardened | cured material obtained from this invention composition will become inadequate.

The molecular weight of the component (A) is preferably about 2,000 to 10,000, particularly about 3,000 to 7,000. If the molecular weight is too small, the elongation of the target coating film may not be sufficiently obtained, and if it is too large, the target condensation reaction product may not be obtained due to gelation during the reaction with the component (B).
In the present invention, the molecular weight or the degree of polymerization can usually be measured as a polystyrene-reduced weight average molecular weight (Mw) or weight average degree of polymerization (Nw) in gel permeation chromatography (GPC) analysis using toluene or the like as a developing solvent. .

<(B) component>
The component (B) to be condensed with the component (A) has a hydroxyl group at both ends (that is, a hydroxydiorganosiloxy group (HO) R ¹ ₂ SiO _1/2 (R ¹ is independently A diorganopolysiloxane raw rubber having a degree of polymerization of 5,000 or more, in particular, the following general formula (1): an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms)
HO— (R ¹ ₂ SiO) _n —H (1)
(In the formula, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10, especially 1 to 6 carbon atoms, and n is an integer of 5,000 or more.)
It is preferable that it is the linear diorganopolysiloxane represented by these.

In the above formula (1), as R ¹ , for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, Alkyl groups such as octyl group, nonyl group, decyl group; cycloalkyl groups such as cyclopentyl group, cyclohexyl group; alkenyl groups such as vinyl group, allyl group, isopropenyl group, butenyl group, pentenyl group, hexenyl group; phenyl group, Aryl groups such as tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group; chloromethyl group, 3-chloropropyl group, 1-chloro-2-methylpropyl group, 3, 3 And halogenated alkyl groups such as 3-trifluoropropyl group. Among them, methyl group is preferred. .

  In the above formula (1), n (degree of polymerization) is 5,000 or more, preferably 5,000 to 200,000, more preferably 5,000 to 20,000, and particularly preferably 6,000 to 12,000. It is an integer. If the degree of polymerization is less than 5,000, the desired high elongation cannot be obtained, and if it exceeds 20,000, the viscosity of the composition may become so high that it is not suitable for coating even when diluted with a solvent.

<Condensation reaction between component (A) and component (B)>
The organopolysiloxane of component (I) is based on 80 to 20 parts by mass of the component (A) (that is, 80 to 20% by mass in the total of components (A) and (B)). It can be obtained by a condensation reaction using 20 to 80 parts by mass (that is, 20 to 80% by mass in the total of components (A) and (B)). When the amount of the component (A) used is less than 20% by mass, the cured product obtained from the composition of the present invention does not have rubber strength, and when it exceeds 80% by mass, the resulting cured product is obtained. The elongation of the object is lowered and the rubber elasticity is impaired.

In the condensation reaction between the component (A) and the component (B), it is preferable to use a condensation reaction catalyst. Examples of the condensation reaction catalyst include titanium compounds, tin compounds, amine compounds, alkali metal compounds, and the like, preferably amine compounds, and specifically, ethylamine, propylamine, isopropylamine, butylamine, diethylamine, diamine. Examples include butylamine, triethylamine, aqueous ammonia and the like.
The amount of the condensation reaction catalyst used is not particularly limited as long as it is an effective amount as a catalyst, but is generally 0.5 to 3.3 with respect to a total of 100 parts by mass of the component (A) and the component (B). It may be about 0 part by mass.

  Further, the condensation reaction temperature is not particularly limited, but is usually in the range of 1 to 120 ° C, preferably 10 to 80 ° C. The reaction time is not particularly limited, but about 1 to 24 hours is sufficient.

  After completion of the condensation reaction, it is desirable to remove the catalyst if possible. When aqueous ammonia is used, it can be distilled off with an ester trap using a solvent capable of azeotropic dehydration such as toluene. When organic amine is used, removal by heating under reduced pressure is effective.

  The resulting condensation reaction products of the component (A) and the component (B) are greatly different in molecular weight, so it is difficult to determine the weight average molecular weight (Mw) in GPC measurement. Basically, the hydroxy group in the component (A) having a weight average molecular weight of 2,000 to 10,000 is preferably (B) having a polymerization degree of 5,000 or more (corresponding to a weight average molecular weight of 370,000 or more). It has a structure obtained by condensation reaction with hydroxy groups at both ends of the component.

[Component (II)]
The component (II) of the composition of the present invention acts as a crosslinking agent of the composition, and has an average of 2 or more, preferably 3 or 4 hydrolyzable groups bonded to silicon atoms in one molecule. A silicon atom represented by the following general formula (2), which is an organosilane compound and / or a partial hydrolysis condensate thereof (that is, an organopolysiloxane having an average of two or more residual hydrolyzable groups in one molecule) An organosilane compound having two or more hydrolyzable groups bonded to 1 and / or a partially hydrolyzed condensate thereof can be used.
R ² _a SiX _4-a (2)
(In the formula, R ² represents an unsubstituted or substituted monovalent hydrocarbon group, X represents a hydrolyzable group, and a represents 0, 1 or 2, preferably 0 or 1.)

In the above formula (2), as R ² , for example, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, Alkyl groups such as octyl group, nonyl group, decyl group; cycloalkyl groups such as cyclopentyl group, cyclohexyl group; alkenyl groups such as vinyl group, allyl group, isopropenyl group, butenyl group, pentenyl group, hexenyl group; phenyl group, Aryl groups such as tolyl group, xylyl group, naphthyl group; aralkyl groups such as benzyl group, phenethyl group, phenylpropyl group; chloromethyl group, 3-chloropropyl group, 1-chloro-2-methylpropyl group, 3, 3 , 3-trifluoropropyl group and other halogenated alkyl groups such as those having 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms. Is a methyl group. Among these, a vinyl group, a phenyl group is preferable.

  As the hydrolyzable group bonded to the silicon atom (X in the above formula (2)), an alkoxy group having 1 to 4, particularly 1 or 2, carbon atoms such as methoxy group, ethoxy group, propoxy group, butoxy group, Examples include dialkyl ketoxime groups such as dimethyl ketoxime group, methyl ethyl ketoxime group and methyl isobutyl ketoxime group, alkenoxy groups having 2 to 4 carbon atoms such as isopropenoxy group, and acyloxy groups such as acetoxy group. A dialkyl ketoxime group is preferred.

  Specific examples of the component (II) include, for example, methyltris (dimethylketoxime) silane, methyltris (methylethylketoxime) silane, ethyltris (methylethylketoxime) silane, methyltris (methylisobutylketoxime) silane, vinyltris (methylethylketoxime) silane. Dialkyl ketoxime silanes; alkoxy silanes such as methyltrimethoxysilane and vinyltrimethoxysilane; alkenoxysilanes such as methyltriisopropenoxysilane; acetoxysilanes such as methyltriacetoxysilane and vinyltriacetoxysilane A silane and its partial hydrolysis-condensation product are mentioned. These can be used singly or in combination of two or more. In particular, dialkyl ketoxime silane hydrolyzable silanes and partial hydrolysates thereof are particularly preferably used from the viewpoints of curability in a thin film, odor, and the like.

  The compounding quantity of this (II) component is 10-50 mass parts with respect to 100 mass parts of said (I) component, Preferably it is the range of 15-45 mass parts. If the blending amount is less than 10 parts by mass, sufficient crosslinking and curing will not occur, so that a cured product having rubber elasticity cannot be obtained, and there is a risk of thickening and gelation over time. Moreover, when it exceeds 50 mass parts, the fall of an elongation and the raise of hardness will occur, and it will be inferior to mechanical characteristics.

[Component (III)]
In addition to the above components (I) and (II), the composition of the present invention further contains (III) a solvent. This compounding component gives an appropriate viscosity to the material and has an effect of adjusting workability during coating. In the present composition, a solvent used in a usual condensation-curable organopolysiloxane composition is preferably used. Specifically, saturated hydrocarbons such as pentane, hexane, heptane, octane, isooctane, cyclohexane, methylcyclohexane, solvent volatile oil, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene, and ketones such as methyl ethyl ketone and methyl isobutyl ketone And esters such as ethyl acetate, low-molecular cyclic siloxanes such as octamethylcyclotetrasiloxane, and isoparaffins. These may be used alone or as a mixture of two or more.

  The compounding quantity of this (III) component is 500-1,500 mass parts with respect to 100 mass parts of said (I) component, and it is preferable that it is 600-1,200 mass parts. When the blending amount is less than 500 parts by mass, sufficient workability may not be obtained, and when it exceeds 1,500 parts by mass, the film thickness of the coating film to be generated is lowered and the coating film strength may be inferior. is there.

[Other ingredients]
The composition of the present invention may further contain a condensation reaction catalyst. Examples of the condensation reaction catalyst include organic titanium compounds such as tetraisopropoxy titanium, tetrabutoxy titanium and titanium bisacetylacetonate; strong bases such as tetramethylguanidine and tetramethylguanidylpropyltrimethoxysilane; γ-aminopropyl Aminosilane coupling agents such as triethoxysilane; zinc octoate, lead 2-ethylhexanoate, dibutyltin diacetate, dibutyltin dilactate, dioctyltin dilaurate, stannous octoate, zinc naphthenate, ferrous octoate, etc. And carboxylic acid metal salts.

  When blending this condensation reaction catalyst, the blending amount may be an effective amount as a catalyst and is not particularly limited, but is usually 0.01 to 5 parts by weight, preferably 100 parts by weight of component (I). About 0.05 to 3 parts by mass are used.

[Preparation of composition]
The composition of the present invention can be obtained by uniformly mixing the above components (I) to (III) and other components as required.

[Use of composition]
The composition of the present invention has good slipperiness on the surface of the molded product by applying and curing to the surface of the silicone rubber molded product, and further follows the deformation of the molded product because the cured coating film has a high elongation. Silicone rubber molded articles whose surface is coated with the coating film can prevent the adhesion of dust, burrs during molding, and foreign materials. Can prevent cracks and cracks.

  Here, examples of the application of the present composition to a silicone rubber molded product that can form a coating film include a catheter that requires smooth insertion of a medical device, an inner surface of a stent, improved slipperiness of a rubber roller, etc., dust For example, waterproofing of precision devices, cellular phones, mobile devices, etc. that do not like adhesion, dust-proof packing, adhesion of gaskets, improvement of ASSY properties by preventing sticking, prevention of sticking of high-temperature pressing members, and the like.

  The composition can be applied by an application method known in the art such as brushing, spraying, dipping or the like. Since the composition has condensation curable properties, it is desirable to avoid contact with moisture for a long time during the operation, and airless spraying, dip using a composition tank capable of purging with nitrogen, and the like are desirable.

  The standard curing conditions for the composition are 23 ° C. and 50% RH × 7 days, but a cured film can be obtained by curing for about 2 hours in a normal room (eg, 20 ° C. ± 15 ° C., 25-80% RH). be able to. Further, in order to speed up the drying of the solvent, a cured film can be obtained in about 30 minutes by drying at 120 ° C.

  In addition, although the thickness of a coating film changes with purposes, it is 50 micrometers or less (for example, 0.5-50 micrometers) normally, Preferably it can use by about 1-10 micrometers. It should be noted that due to the moisture curing property, it takes time to cure the deep part in a thick film of 100 μm or more.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in full detail, this invention is not limited by this. In addition, the polymerization degree and molecular weight of each component are weight average values in terms of polystyrene in GPC analysis (solvent: toluene).

[Synthesis Example 1] Preparation of Component (I) In a four-necked separable flask equipped with a thermometer, a stir bar, and a reflux condenser, (CH ₃ ) ₃ SiO _1/2 unit and SiO _{4 / A} three-dimensional network comprising ₂ units, (CH ₃ ) ₃ SiO _1/2 units / SiO _4/2 units (molar ratio) = 0.75, and the content of hydroxy groups bonded to silicon atoms is 0.10 mol / 100 g. 1,167 g of a solution obtained by dissolving organopolysiloxane having a structure (molecular weight; about 3,200) in toluene so that the solid content is 60% by mass, and a degree of polymerization of about 8,000 (molecular weight; about 600,000) 300 g of linear dimethylpolysiloxane blocked with silanol groups at both ends was uniformly stirred and mixed, 5.0 g of aqueous ammonia was added, and a condensation reaction was carried out at 20 ° C. for 12 hours. Next, an ester trap tube was attached to the separable flask, and azeotropic dehydration was performed by heating to 120 ° C. to distill off ammonia, water, and toluene. Appearance was colorless and transparent, and a toluene solution of a condensation reaction product of the components (A) and (B) having a nonvolatile content of 80% by mass after drying at 105 ° C. for 3 hours was obtained. Furthermore, 120 g of toluene was added to 200 g of the obtained solution to adjust the non-volatile matter mass to 50%. It was set to 1.

[Example 1]
Component (I) obtained in Synthesis Example 1: The composition 1 was prepared by adding 30 g of vinyltris (methylethylketoxime) silane as the component (II) and 800 g of normal pentane as the component (III) to 200 g of 1, and mixing uniformly.

[Example 2]
Composition 2 was prepared in the same manner as in Example 1, except that the amount of vinyltris (methylethylketoxime) silane was 40 g, and 1 g of γ-aminopropyltriethoxysilane was further added.

[Example 3]
Composition 3 was prepared in the same manner as in Example 1, except that 30 g of vinyltris (methylethylketoxime) silane was added to 40 g of methyltris (methylethylketoxime) silane and 0.1 g of dioctyltin dilaurate was further added.

[Synthesis Example 2] Preparation of Component (I ') (Comparative Reaction Product) A four-necked separable flask equipped with a thermometer, a stir bar, and a reflux condenser was charged with (CH ₃ ) ₃ SiO _{1 /} as component (A). ₂ units and SiO _4/2 units, (CH ₃ ) ₃ SiO _1/2 units / SiO _4/2 units (molar ratio) = 0.75, and the content of hydroxy groups bonded to silicon atoms is 0.10 mol / 1167 g of a solution prepared by dissolving 100 g of a three-dimensional network-organopolysiloxane (molecular weight; about 3,200) in toluene so that the solid content is 60% by mass; After stirring 300 g of linear dimethylpolysiloxane with a silanol group blocked at both ends with a viscosity of 700 mPa · s (polymerization degree: about 260) uniformly and stirring, 5.0 g of ammonia water was added and the mixture was stirred at 20 ° C. for 12 hours. A condensation reaction was performed. Next, an ester trap tube was attached to the separable flask, and azeotropic dehydration was performed by heating to 120 ° C. to distill off ammonia, water, and toluene. Appearance was colorless and transparent, and a toluene solution of a condensation reaction product of the component (A) and the component (B) having a nonvolatile content of 77% by mass after drying at 105 ° C. for 3 hours was obtained. Further, 70 g of toluene was added to 130 g of the obtained solution to adjust the non-volatile matter mass to 50%. 2.

[Comparative Example 1]
Component (I ′) obtained in Synthesis Example 2: 2 was added to 30 g of vinyltris (methylethylketoxime) silane as component (II) and 800 g of normal pentane as component (III), and mixed uniformly to prepare composition 4.

Synthesis Example 3 Preparation of Component (I ″) (Comparative Reaction Product) A four-necked separable flask equipped with a thermometer, a stir bar, and a reflux condenser was charged with (CH ₃ ) ₃ SiO _{1 / 2} units and SiO _4/2 units, (CH ₃ ) ₃ SiO _1/2 units / SiO _4/2 units (molar ratio) = 0.75, and the content of hydroxy groups bonded to silicon atoms is 0.10 mol / 1,000 g of a solution prepared by dissolving 100 g of an organopolysiloxane having a three-dimensional network structure (molecular weight; about 3,200) in toluene so that the solid content is 60% by mass is replaced with component (B), 25 After uniformly stirring and mixing 600 g of linear dimethylpolysiloxane (polymerization degree: about 1,100) with both ends silanol groups blocked at a viscosity of 100,000 mPa · s at 20 ° C., 5.0 g of ammonia water was added and 20 Conduct the condensation reaction at 12 ℃ for 12 hours Next, an ester trap tube was attached to the separable flask, and azeotropic dehydration was performed by heating to 120 ° C. to distill off ammonia, water, and toluene, and the appearance was colorless and transparent, and the non-volatile content after drying at 105 ° C. for 3 hours. A toluene solution of the condensation reaction product of the component (A) and the component (B) that was 80% by mass was obtained, and 120 g of toluene was added to 200 g of the resulting solution to adjust the nonvolatile content mass to 50%. I ″) component: No. It was set to 3.

[Comparative Example 2]
Component (I ″) obtained in Synthesis Example 3: To 200 g of No. 3, add 30 g of vinyltris (methylethylketoxime) silane as component (II) and 800 g of normal pentane as component (III), and mix uniformly. Composition 5 was prepared.

  The obtained compositions 1 to 5 were applied onto a 2 mm thick silicone rubber sheet with a brush and cured at 20 ° C. and 50% RH for 24 hours to form a coating film having a thickness of about 10 μm. Table 1 shows the results of checking the slipperiness of the surface of the coating film by finger touch and evaluating according to the following criteria. Moreover, the obtained sheet | seat was cut | disconnected to the width of 10 mm, the surface crack at the time of 100% expansion | extension, the presence or absence of a crack at the time of 300% expansion | strain was confirmed visually, and the following reference | standard evaluated. The results are also shown in Table 1.

[Slipperiness]
Good: Cleaned with ethanol, with a very smooth touch even when lightly touched with a dry finger. Bad: Cleaned with ethanol, touched with a dry finger.

[Crack, crack]
None: When the tensile tester is stretched 100% or 300% at a tensile speed of 50 mm / min, there is no change in the appearance when stretched or restored. Existence: 100% at a tensile speed of 50 mm / min with a tensile tester. When it is stretched 300%, it cracks in the direction perpendicular to the stretching direction, cracks appear, and the appearance remains unchanged when restored

Claims (5)

(I) Organo, which is a condensation reaction product of 80 to 20 parts by mass of the following component (A) and 20 to 80 parts by mass of component (B) (the total of components (A) and (B) is 100 parts by mass) Polysiloxane: 100 parts by mass,
(A) R ₃ SiO _1/2 unit (wherein R independently represents an unsubstituted or substituted monovalent hydrocarbon group having 1 to 6 carbon atoms) and a SiO _4/2 unit, and SiO _{4 / The} number of moles of R ₃ SiO _1/2 units per mole of ₂ units is 0.6 to 1.2 moles, and further R ₂ SiO _2/2 units and RSiO _3/2 units (wherein R is Can be contained in an amount of 0 to 1.0 mol per mol of SiO _4/2 units, and 0.02 to 0.12 mol / 100 g of hydroxy groups bonded to silicon atoms. Siloxane (B) Diorganopolysiloxane raw rubber having a hydroxy group at both ends and a polymerization degree of 5,000 or more (II) Organosilane compound having two or more hydrolyzable groups in one molecule bonded to a silicon atom and / or The partial hydrolysis condensate: 10-50 mass ,
(III) Solvent: A room temperature-curable organopolysiloxane composition containing 500 to 1,500 parts by mass. The component (B) is represented by the following general formula (1):
HO— (R ¹ ₂ SiO) _n —H (1)
(In the formula, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and n is an integer of 5,000 or more.)
The composition according to claim 1, which is a linear diorganopolysiloxane represented by the formula: The component (II) is an organosilane compound having two or more hydrolyzable groups bonded to a silicon atom represented by the following general formula (2) and / or a partial hydrolysis condensate thereof. The composition according to 1 or 2.
R ² _a SiX _4-a (2)
(In the formula, R ² is an unsubstituted or substituted monovalent hydrocarbon group, X is a hydrolyzable group, and a represents 0, 1 or 2.)   The composition according to claim 1, 2 or 3, wherein the hydrolyzable group of the component (II) is a dialkyl ketoxime group.   A silicone rubber molded article having a surface coated with a coating film obtained by curing the composition according to any one of claims 1 to 4.