JP2010106210A - Two-part type condensation-curable organopolysiloxane composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a two-part type condensation curable organopolysiloxane composition where the first agent can be easily mixed with the second agent, in equivalent amounts, and is excellent in fast curability as well as the curability in a deep portion. <P>SOLUTION: The two-part type condensation curable organopolysiloxane composition comprises: the first agent containing (A) 100 pts.mass of a diorganopolysiloxane having both ends terminated with a hydroxy group, (B) 0.5-10 pts.mass of a silane and/or siloxane having ≥3 alkenoxysilyl groups in its molecule, and (C) 0.01-10 pts.mass of a curing catalyst; and the second agent containing (D) a diorganopolysiloxane having both ends terminated with a hydroxy group and no silane and/or siloxane of component (B), wherein the mass ratio of the first agent to the second agent is in a range of 25:75-75:25. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a two-component condensation curable organopolysiloxane composition useful as a silicone-based sealing agent, adhesive, coating agent, potting agent, etc., and in particular, a deacetone-type two-component with good fast curing and deep part curing. The present invention relates to a type condensation curable organopolysiloxane composition.

  Condensation-curing room temperature fast-curing organopolysiloxane compositions have conventionally been a one-pack type in which the crosslinking agent is reduced to the limit to improve the crosslinking rate by hydrolysis, and the crosslinking agent and curing agent are packaged separately. The two-part type is known. However, although the one-component composition has a high curing rate from the surface, it requires a certain amount of time for deep-curing, and as a whole cannot be said to be fast-curing. Although the two-component composition is relatively excellent in deep-part curability, handling is troublesome because the ratio of the first agent (main agent) and the second agent (curing agent) to be mixed is not 1: 1. Also, there is a drawback that it is difficult to adapt to an automatic mixer. Further, in order to completely cure to the deep part, it is necessary to strictly define the addition amount of the crosslinking agent and the curing agent or to add water as the deep part curing agent. In the case of a dealcohol-free two-component composition, the depolymerization of the siloxane proceeds by the alcohol generated as a by-product during curing and the tin catalyst contained, and the cured product is easily softened or liquefied at a relatively low temperature. I have a point.

  On the other hand, in addition-curable organopolysiloxane compositions, it is easy to make the ratio of the first agent and the second agent at the time of two-component mixing 1: 1, so that the workability is excellent. Requires a heating furnace. Further, since the curing catalyst is easily poisoned in the presence of an additional poison, there is a disadvantage that the working environment is limited.

  In order to solve the above-mentioned problems, a technique has been proposed in which no silane or siloxane having a hydrolyzable group, which is a condensation-curing type crosslinking agent, is used. In Patent Document 1, an oil in which the ends of a diorganopolysiloxane having a hydroxyl group at both ends are blocked with a silane having a hydrolyzable group is prepared in advance and mixed with the endblocked oil and an organopolysiloxane having a silanol group. Liquid composition has been proposed. However, preparation of an oil whose end has been blocked in advance requires a previous step, which is disadvantageous in terms of process, and the blocking oil itself has a reactivity with moisture, so that handling is extremely difficult.

In order to solve these problems, it is effective to generate water in the system of the composition. In Patent Document 2, a deep curing agent is used as a by-product of water produced as a by-product in the ketimination reaction of an organic compound having at least one C═O group in one molecule and an organic compound having at least one NH ₂ group in one molecule It has been proposed to be used as Patent Document 3 proposes the use of water produced as a by-product in the ketimination reaction of a ketone compound generated from alkenoxysilane and a primary amine compound as a deep curing agent. In Patent Document 4, it is proposed to use water produced as a by-product by a Michael addition reaction between a β-ketoester compound and an organic compound having at least one NH ₂ group in one molecule as a deep curing agent. However, in these compositions, in order to supply a sufficient amount of moisture for the crosslinking reaction, an organic compound having a C═O group and an organic compound having an NH ₂ group, an alkenoxysilane and a primary amine compound Alternatively, it is necessary to add volatile components such as β-ketoester and an organic compound having an NH ₂ group to the composition. However, there are cases where the application of environmentally hazardous substances such as sick house regulations and VOC regulations has become stricter and is limited to the application.

  Patent Document 5 discloses that a deep curing agent contains water generated by a neutralization reaction between a carboxylic acid generated by hydrolysis of a hydrolyzable silane having at least two acyloxy groups in the molecule or a partial hydrolyzate thereof and an inorganic filler. It has been proposed to be used as However, the curable type producing carboxylic acid has a problem that its application range is very narrow due to the problem of metal corrosion.

  Patent Document 6 proposes supplying moisture directly to the composition by blending moisture-containing wet silica and using it as a deep curing agent. However, if moisture is directly supplied, it is difficult to control the speed of the curing reaction, and it is very difficult to ensure good workability.

Patent Document 7 describes a room temperature-curable organopolysiloxane composition having excellent fluidity using an amino group-containing silane and a 1-methylvinyloxy-containing silane. This amino group-containing silane is hydrolyzed. Therefore, since a compound having a —NH ₂ group is not generated, it does not become fast curing.

Japanese Patent Laid-Open No. 7-166603 Japanese Patent No. 2811134 Japanese Patent No. 2841155 Japanese Patent No. 3112188 JP 2002-338811 A JP 2002-12767 A JP 2000-129130 A

  The present invention has been made in view of the above circumstances, solves the above problems, is industrially easy to produce, and can easily set the ratio of mixing the first agent and the second agent to 1: 1. A two-component condensation-curable organopolysiloxane composition that does not cause depolymerization of the organopolysiloxane, does not require the addition of a large amount of volatile components, and yet achieves fast curing and deep curing. The purpose is to provide.

  As a result of investigations to achieve the above object, the present inventors have reached the composition of the present invention. That is, endblocking can be performed in the production process by mixing diorganopolysiloxane having both ends blocked with hydroxyl groups and silane having an alkenoxysilyl group in the molecule in the presence of a catalyst. It has been found that depolymerization does not occur even when it is prepared as a two-part composition combined with diorganopolysiloxane having both ends of the molecular chain blocked with hydroxyl groups. Moreover, it has been found that such a two-part composition can provide good fast curability and deep part curability, and has led to the present invention.

That is, the present invention
(A) Diorganopolysiloxane having both ends of the molecular chain blocked with hydroxyl groups: 100 parts by mass,
(B) Silane having 3 or more alkenoxysilyl groups in the molecule and / or siloxane having 3 or more alkenoxysilyl groups in the molecule: 0.5 to 10 parts by mass,
(C) Curing catalyst: first agent containing 0.01 to 10 parts by mass;
(D) a diorganopolysiloxane having both ends of the molecular chain blocked with hydroxyl groups, the second component not containing silane and / or siloxane as the component (B), and the first agent and the second agent A two-component condensation-curable organopolysiloxane composition having a mass ratio of 25:75 to 75:25 with the agent is provided.

  The two-component condensation-curable organopolysiloxane composition of the present invention is industrially easy to produce because it uses diorganopolysiloxane having both ends blocked with hydroxyl groups as a raw material. The ratio of the first agent and the second agent can be adjusted flexibly, and it is easy to set it to 1: 1. Further, depolymerization of the main component organopolysiloxane does not occur. In addition, it is not necessary to use a large amount of volatile components, and the composition is excellent in fast curability and deep curability.

  Hereinafter, the present invention will be described in more detail.

[(A) component]
A typical example of the diorganopolysiloxane in which both ends of the molecular chain of the component (A) are blocked with hydroxyl groups is represented by the following general formula.
HO— (R ₂ SiO) _n —H
(In the formula, each R is independently an unsubstituted or substituted monovalent hydrocarbon group, and n represents an integer of 100 or more.)
In the above general formula, each R is independently an unsubstituted or substituted monovalent hydrocarbon group. Examples of R include an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and a part or all of hydrogen atoms of these hydrocarbon groups. Group substituted with a halogen atom such as fluorine and chlorine. Examples of the alkyl group (in this specification, the alkyl group is used to include a cycloalkyl group) include a methyl group, an ethyl group, a propyl group, a cyclohexyl group, and the like. Examples of the alkenyl group include a vinyl group and an allyl group. Examples of the aryl group include a phenyl group. Examples of the halogen atom substituent include a 3,3,3-trifluoropropyl group. Among these, a methyl group, a vinyl group, and a phenyl group are preferable, and a methyl group is particularly preferable.

  In the above general formula, n is an integer of 100 or more, and the viscosity of the diorganopolysiloxane at 25 ° C. is preferably 100 to 1,000,000 mPa · s, more preferably 300 to 100,000 mPa · s, The number is particularly preferably 700 to 50,000 mPa · s. If the viscosity is too small, sufficient mechanical properties may not be obtained in the cured product, and if it is too large, the viscosity of the composition may increase and workability may decrease. Here, the viscosity is a value measured by a rotational viscometer.

Specific preferred examples of the component (A) include the following compounds.
HO— (Me ₂ SiO) _n —H
_{HO- (Me 2 SiO) n1 -} (PhMeSiO) n2 -H
_{HO- (Me 2 SiO) n1 -} (Ph 2 SiO) n2 -H
_{HO - [(CF 3 C 2} H 4) (Me) SiO] n -H
_{HO- (Me 2 SiO) n1 -} [(CF 3 C 2 H 4) (Me) SiO] n2 -H
(Wherein, n is as defined above, n _1, n ₂ is an integer of 1 or more satisfying _{n 1 + n 2 = n,} Me represents a methyl group, Ph refers to a phenyl group.)
[Component (B)]
The silane and / or siloxane having 3 or more alkenoxysilyl groups in the molecule of the component (B) is a supply source of an organic compound having a crosslinking agent and a C═O group, and is represented by the following formula: Xylsilane or a partial hydrolyzate thereof is preferable.

_{^{R 1 x -Si (O-CR}} 2 = CR 3 R 4) 4-x
(Wherein R ¹ and R ² are substituted or unsubstituted monovalent hydrocarbon groups, R ³ and R ⁴ are each a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R ² and R ³ And may form an alicyclic ring having a C═C double bond in the above formula together with the carbon atom to which they are bonded. X represents 0 or 1.)
In the above formula, R ¹ and R ² are each a substituted or unsubstituted monovalent hydrocarbon group, preferably having 1 to 10 carbon atoms. Monovalent hydrocarbon groups include alkyl groups such as methyl, ethyl, propyl, butyl, and cyclohexyl groups, alkenyl groups such as vinyl and allyl groups, aryl groups such as phenyl groups, and aralkyl groups such as benzyl groups. And halogen-substituted alkyl groups such as 3,3,3-trifluoropropyl group. Particularly preferred are a methyl group, an ethyl group, a vinyl group and a phenyl group.

R ³ and R ⁴ are each a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, and the monovalent hydrocarbon group is preferably a group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, or a propyl group. Alkyl groups such as isopropyl group, butyl group and isobutyl group. Further, R ² and R ³ may be bonded to form an alicyclic ring having a C═C double bond in the above formula together with the carbon atom to which these are bonded. In this case, the above equation is

-R ² -R ³ -represents an alkylene group, preferably an alkylene group having 3 or 4 carbon atoms (trimethylene group or tetramethylene group).

When the R ³ do not form the aforementioned alicyclic with R ² is particularly preferred as R ³ and R ⁴ are hydrogen atom, a methyl group, an ethyl group. When R ² and R ³ combine to form —R ² —R ³ —, —R ² —R ³ — is preferably — (CH ₂ ) ₄ —, in which case R ⁴ is a hydrogen atom. It is preferable that

  The present crosslinking agent can be obtained, for example, by dehydrochlorinating a corresponding chlorosilane and an organic compound having a C═O group. If necessary, a hydrochloric acid scavenger such as triethylamine can be used in combination during the reaction.

  The blending amount of the silane and / or siloxane having 3 or more alkenoxysilyl groups as the component (B) is preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the diorganopolysiloxane as the component (A). Is 1-8 parts by mass. If it is less than 0.5 part by mass, sufficient curability cannot be obtained, and if it exceeds 10 parts by mass, the deep part curability of the composition is lowered and workability is lowered.

[Component (C)]
The (C) component curing catalyst acts as a catalyst for the reaction in which the (B) component blocks the hydroxyl groups that the (A) component has at both ends in the composition of the present invention, and is thus produced during two-component mixing. It acts as a condensation reaction catalyst between the reaction product of component (A) and component (B) and component (D). As the component (C), one type may be used alone, or two or more types may be used as a mixture.

Specific examples of the component (C) include tin dioctoate, dimethyltin diversate, dibutyldimethoxytin, dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, dibutyltin dibenzyl malate, dioctyltin dilaurate and the like. A salt catalyst, a tin catalyst composed of a tin chelate compound such as acetylacetonate tin, a strong base compound such as guanidine, DBU (1,8-diazabicyclo [5.4.0] -7-undecene), a guanidyl group, a biguanide group alkoxysilane having such, tetraisopropoxytitanium, tetra -n- butoxytitanium, tetrakis (2-ethylhexoxy) titanium, dipropoxybis (acetylacetonato g) titanium, titanium-isopropoxy octylene glycol Titanate ester or titanium chelate compounds and the like. In particular, strong base compounds such as guanidine and DBU (1,8-diazabicyclo [5.4.0] -7-undecene) and alkoxysilanes having guanidyl group, biguanide group, etc., particularly alkoxysilanes having guanidyl group such as tetra It is preferable to use methylguanidylpropyltrimethoxysilane or the like.

  (C) The compounding quantity of component is 0.01-10 mass parts with respect to 100 mass parts of (A) component diorganopolysiloxane, Preferably it is 0.02-5 mass parts. If it is less than 0.01 part by mass, sufficient curing characteristics cannot be obtained, and if it exceeds 10 parts by mass, the durability of the composition is lowered.

[(D) component]
The diorganopolysiloxane in which both ends of the molecular chain used as the component (D) which is an essential component of the second agent are blocked with a hydroxyl group is the same compound as that used as the component (A) described above, and (A The above description of the component) applies to the component (D), including preferred examples.

  However, in the case of component (D), the two-component condensation-curable organopolysiloxane composition of the present invention easily achieves 1: 1 as the mixing ratio (mass ratio) of the first agent and the second agent. In order to impart deep part curability to the composition, the component (D) is a degree of polymerization (meaning an average degree of polymerization calculated from a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography. The same applies hereinafter). Deep-curability is further improved by a mixture of diorganopolysiloxane having both ends of 100 or more molecular chains blocked with hydroxyl groups and diorganopolysiloxane having both degree of polymerization of 50 or less and blocked with hydroxyl groups This is preferable. In this case, the ratio (mass ratio) of the diorganopolysiloxane having both ends of the molecular chain having a degree of polymerization of 100 or more blocked with hydroxyl groups and the diorganopolysiloxane having both ends of the molecular chain having a degree of polymerization of 50 or less blocked by hydroxyl groups is The range is 100: 0 to 90:10, preferably 100: 0 to 95: 5, and more preferably 99: 1 to 95: 5. When the proportion of diorganopolysiloxane having both polymerization chain ends with a degree of polymerization of 50 or less blocked with a hydroxyl group exceeds 10% by mass, the rubber strength after curing decreases.

  In addition, (D) component has the preferable range of 50-200 mass parts with respect to 100 mass parts of (A) component, 75-150 mass parts is more preferable, It is especially preferable that it is 80-120 mass parts.

  The second agent contains the component (D) as the main component and does not contain the component (B), and may contain the component (C), the component (E), the component (F), and an optional component described later. , (D) component or (D) component and (F) component (including wetter when wetter is used) are preferable.

[(E) component]
When the adhesiveness is required, the composition of the present invention can contain (E) a silane coupling agent as an adhesion-imparting component. A well-known thing is used suitably as a silane coupling agent. In particular, as the hydrolyzable group, those having an alkoxysilyl group and having two or less alkenoxysilyl groups in the molecule are preferable. Vinyltris (β-methoxyethoxy) silane, methacryloxypropyltrimethoxysilane, β- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, glycidoxypropyltrimethoxysilane, glycidoxypropylmethyldiethoxysilane, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, aminopropyltriethoxysilane, Examples include mercaptopropyltrimethoxysilane, glycidoxypropyltriisopropenoxysilane, glycidoxypropylmethyldiisopropenoxysilane, and the like. Of these, aminosilane coupling agents are particularly preferred.

  When the silane coupling agent is blended, the blending amount is 0.1 to 10 parts by weight, particularly 0.2 to 100 parts by weight with respect to a total of 100 parts by weight of the (A) component and the (D) component diorganopolysiloxane. 5 parts by mass is preferred. If the amount is less than 0.1 parts by mass, sufficient adhesiveness may not be obtained, and if it exceeds 10 parts by mass, it may be disadvantageous in price.

  In addition, the component (E) can be added to the first agent and / or the second agent in the blending as the two-component condensation curable organopolysiloxane composition, but it is desirable to add it to the first agent.

[(F) component]
The composition of the present invention can further contain (F) a filler, which acts as a reinforcing agent and a bulking agent in the composition of the present invention. Examples of the filler of component (F) include reinforcing fillers such as fumed silica, wet silica, precipitated silica, and calcium carbonate, metal oxides such as aluminum oxide and zinc oxide, metal hydroxides, and carbon black. , Glass beads, glass balloons, resin beads, resin balloons and the like. Preference is given to fumed silica, precipitated silica, calcium carbonate and zinc oxide. Even if these fillers are not surface-treated, they may be surface-treated with a known treating agent.

(F) When mix | blending the filler of a component with this invention composition, the compounding quantity is 1-500 mass parts with respect to a total of 100 mass parts of (A) component and the diorganopolysiloxane of (D) component. Particularly preferred is 2 to 250 parts by mass. If it is less than 1 part by mass, the effect of addition may be insufficient. If it exceeds 500 parts by mass, the dischargeability and workability of the composition of the present invention may be deteriorated.

  In addition, when blended as a two-component condensation-curable organopolysiloxane composition, the component (F) may be added only to the first agent, only to the second agent, or both the first and second agents. it can. In consideration of mixing variation during two-component mixing, it is advantageous to stabilize the physical properties after curing by adding almost the same amount of the same component to both the first agent and the second agent.

[Other ingredients]
In the composition of the present invention, a known additive as an additive for the room temperature curable organopolysiloxane composition may be added within a range that does not impair the object of the present invention. For example, polyether as a thixotropy improver, non-reactive dimethyl silicone oil as a plasticizer, isoparaffin, reticulated polysiloxane composed of trimethylsiloxy units and SiO ₂ units as a crosslink density improver, and the like.

  Furthermore, as necessary, colorants such as pigments, dyes, fluorescent brighteners, fungicides, antibacterial agents, cockroach repellents, bioactive additives such as marine organism repellents, and non-reactive phenyl as bleed oil Surface modifiers such as silicone oil, fluorosilicone oil, organic liquid incompatible with silicone, solvents such as toluene, xylene, solvent volatile oil, cyclohexane, methylcyclohexane, and low boiling point isoparaffin may also be added.

[Preparation and curing of composition]
The two-component room temperature curable organopolysiloxane composition of the present invention is prepared by preparing the above components (A) to (D), and if necessary, (E), (F) components and other components, It can be obtained by separately mixing the second agent separately using a known kneader such as a planetary mixer.
In the mixed use, separately prepared (A), (B), (C) component, first component consisting of (E), (F) component and other components as required, and (D) component If necessary, measure the amount of the second agent consisting of components (E) and (F) and other components before use and stir and mix with a metal spatula, or mix with a static mixer or dynamic mixer. It is easy to use.

  The ratio of the first agent to the second agent is preferably in the range of 25:75 to 75:25 by mass ratio, more preferably 40:60 to 60:40, and even more preferably 45:55 to 55:45. Yes, particularly preferably 50:50.

[Use of composition]
The room temperature fast-curing organopolysiloxane composition of the present invention can be suitably used as a sealing agent, an adhesive, a coating agent, a potting agent and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. In addition, in the following example, a viscosity shows the value in 25 degreeC measured with the rotational viscometer.

[Example 1]
First agent (1-1):
100 parts by mass of dimethylpolysiloxane having a viscosity of 700 mPa · s blocked at both ends with hydroxyl groups, 8 parts by mass of vinyltriisopropenoxysilane, and 1.0 part by mass of tetramethylguanidylpropyltrimethoxysilane are mixed until uniform. To prepare a composition.

Second agent (1-2):
As a second agent, 100 parts by mass of dimethylpolysiloxane having a viscosity of 700 mPa · s and having both ends blocked with hydroxyl groups was prepared.

  The first agent and the second agent are weighed in the same amount of 25 g each in a resin cup, mixed with a metal spatula, filled into a glass petri dish with a depth of 15 mm, and cured after curing for 24 hours at 23 ° C. and 50% RH. The film thickness (thickness of the cured part) was confirmed.

[Comparative Example 1]
The first agent (1-1) was filled in a glass petri dish having a depth of 15 mm, and the cured film thickness (thickness of the cured part) was confirmed after curing for 24 hours at 23 ° C. and 50% RH.

[Comparative Example 2]
The second agent (1-2) was filled into a glass petri dish having a depth of 15 mm, and the cured film thickness (thickness of the cured part) was confirmed after curing at 23 ° C. and 50% RH for 24 hours.

[Example 2]
First agent (2-1):
As a first agent, 50 parts by mass of dimethylpolysiloxane having a viscosity of 3000 mPa · s blocked at both ends with a hydroxyl group and 10 parts by mass of EROSIL 200 (manufactured by Nippon Aerosil Co., Ltd., fumed silica) are heat-treated and mixed at 150 ° C. for 2 hours. Applying this roll, 50 parts by mass of dimethylpolysiloxane having a viscosity of 1000 mPa · s blocked at both ends with hydroxyl groups, and 10 parts by mass of dimethylpolysiloxane having a viscosity of 50 mPa · s blocked at both ends by trimethylsiloxy groups Until the mixture is further mixed, 5 parts by mass of phenyltriisopropenoxysilane, 1.0 part by mass of tetramethylguanidylpropyltrimethoxysilane, and 2.0 parts by mass of γ-aminopropyltriethoxysilane are made uniform. A composition (first agent (2-1)) was prepared by mixing.

Second agent (2-2):
As the second agent, 50 parts by mass of dimethylpolysiloxane having a viscosity of 3000 mPa · s (degree of polymerization: about 350) blocked at both ends with hydroxyl groups, and 10 parts by mass of EROSIL 200 (manufactured by Nippon Aerosil Co., Ltd., fumed silica) at 150 ° C. After heat mixing for 2 hours, three rolls are applied, and 47 parts by mass of dimethylpolysiloxane having a viscosity of 1000 mPa · s (polymerization degree: about 280) blocked at both ends with a hydroxyl group, and both ends blocked with a trimethylsiloxy group 18 parts by weight of dimethylpolysiloxane having a viscosity of 50 mPa · s and 3 parts by weight of dimethylpolysiloxane having a polymerization degree of 14 blocked at both ends with hydroxyl groups were mixed until uniform (second agent (2-2) ) Was prepared.

  Fill the first cartridge (2-1) and the second agent (2-2) into a 1: 1 mixing specification double cartridge with 18-stage static mixer, and fill the glass petri dish with a depth of 15 mm with a dedicated gun. After the mixture was discharged and cured at 23 ° C. and 50% RH for 24 hours, the cured film thickness (the thickness of the cured part) was confirmed. In addition, 50 g of the mixture was weighed in a 100 ml paper cup, and the flow stop time (time until the surface of the composition did not change even when the paper cup was tilted and lost fluidity) was measured at 23 ° C. and 50% RH. .

[Comparative Example 2]
The composition of the first agent (2-1) was put in a glass petri dish having a depth of 15 mm, and the cured film thickness was confirmed after curing at 23 ° C. and 50% RH for 24 hours. In addition, 50 g of the mixture was weighed in a 100 ml paper cup, and the flow stop time (time until the surface of the composition did not change even when the paper cup was tilted and lost fluidity) was measured at 23 ° C. and 50% RH. .

[Comparative Example 4]
The composition of the second agent (2-2) was put in a glass petri dish with a depth of 15 mm, and the cured film thickness was confirmed after curing at 23 ° C. and 50% RH for 24 hours. In addition, 50 g of the mixture was weighed in a 100 ml paper cup, and the flow stop time (time until the surface of the composition did not change even when the paper cup was tilted and lost fluidity) was measured at 23 ° C. and 50% RH. .

* Note: In Comparative Example 4, measurement was not possible because it was not cured.

Claims (6)

(A) Diorganopolysiloxane having both ends of the molecular chain blocked with hydroxyl groups: 100 parts by mass,
(B) Silane having 3 or more alkenoxysilyl groups in the molecule and / or siloxane having 3 or more alkenoxysilyl groups in the molecule: 0.5 to 10 parts by mass,
(C) Curing catalyst: first agent containing 0.01 to 10 parts by mass;
(D) a diorganopolysiloxane having both ends of the molecular chain blocked with hydroxyl groups, and (B) a second agent that does not contain silane / or siloxane as a component, and the first agent and the second agent Is a two-component condensation-curable organopolysiloxane composition having a mass ratio of 25:75 to 75:25. The component (D) is a mixture of a diorganopolysiloxane in which both ends of a molecular chain having a polymerization degree of 100 or more are blocked with hydroxyl groups and a diorganopolysiloxane in which both ends of a molecular chain having a polymerization degree of 50 or less are blocked with hydroxyl groups. The composition of claim 1. The composition according to claim 1, wherein the component (B) is an alkenoxysilane represented by the following formula and / or a partial hydrolyzate thereof.
_{^{R 1 x -Si (O-CR}} 2 = CR 3 R 4) 4-x
(Wherein R ¹ and R ² are substituted or unsubstituted monovalent hydrocarbon groups, R ³ and R ⁴ are each a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group, R ² and R ³ And may form an alicyclic ring having a C═C double bond in the above formula together with the carbon atom to which they are bonded. X represents 0 or 1.) Furthermore, (E) Silane coupling agent: 0.1-10 mass parts is contained, The composition of any one of Claims 1-3 characterized by the above-mentioned. Furthermore, (F) filler: 1-500 mass parts is contained, The composition of any one of Claims 1-4 characterized by the above-mentioned. The composition according to any one of claims 1 to 4, wherein the curing catalyst (C) is selected from guanidine, 1,8-diazabicyclo [5.4.0] -7-undecene, and alkoxysilane having a guanidyl group. object.