JP5106914B2 - Room temperature curable organopolysiloxane composition - Google Patents

Description

  The present invention is a dealcohol that becomes an adhesive rubber having excellent curability, high strength, high modulus, and excellent moisture resistance and warm water resistance by blending a specific long-chain alkyl group-containing silane compound. Type room temperature curable organopolysiloxane composition. The room temperature curable organopolysiloxane composition of the present invention is particularly suitably used for a multi-layer glass seal application.

  Conventionally composed of organopolysiloxane having a hydroxyl group at the molecular chain end, a reaction product or mixture of aminoalkylalkoxysilane and epoxyalkylalkoxysilane and a curing catalyst, and has adhesiveness to various substrates that are in contact during curing Organopolysiloxane compositions are known (Patent Document 1). However, the silicone rubber obtained by curing this composition has a drawback that its adhesive strength is reduced in a water-resistant adhesive property, particularly in a harsh environment such as hot water immersion in float glass.

Moreover, in order to improve water-resistant adhesiveness, it has been proposed to add a disilaalkane compound (Patent Documents 2 and 3), but the effect is not sufficient.
Japanese Patent Publication No. 63-23226 JP-A 64-60656 JP 2003-221506 A

  The present invention is a room temperature curable organopolysiloxane composition that improves the above-mentioned drawbacks of the prior art, has excellent curability, has high strength, high modulus, and has excellent moisture resistance and warm water resistance. The purpose is to provide.

  As a result of intensive studies to achieve the above object, the present inventors have obtained a room temperature curable organopolysiloxane composition having the above-mentioned excellent characteristics by blending a specific long-chain alkyl group-containing silane compound. The present invention has been completed.

That is, the present invention
(A) 100 parts by weight of a polyorganosiloxane having molecular chain terminals blocked with silanol groups and having a viscosity at 25 ° C. of 500 to 100,000 cSt,
(B) 0.1-20 parts by weight of a long-chain alkyl group-containing silane compound represented by the following general formula,
R ¹ R ² _a Si (OR ³ ) _3-a
(In the formula, R ¹ represents an alkyl group having 5 to 20 carbon atoms, R ² represents a monovalent hydrocarbon, and R ³ represents an alkyl group. A is an integer of 0 or 1.)
(C) 0.1-20 parts by weight of a reaction mixture of aminoalkylalkoxysilane and epoxyalkylalkoxysilane, and
(D) A room temperature-curable organopolysiloxane composition comprising 0.001 to 10 parts by weight of a curing catalyst.

  The polyorganosiloxane as the component (A) of the composition of the present invention is a chain polymer in which both ends are blocked with silanol groups. Further, the component (A) may contain a branched polymer.

  (A) The organic group bonded to the silicon atom in the diorganosiloxane that is the structural unit of the component may be the same or different, for example, methyl group, ethyl group, propyl group, butyl group, hexyl group, dodecyl group, etc. Alkyl groups such as vinyl and allyl groups; aryl groups such as phenyl and tolyl groups; aralkyl groups such as benzyl, β-phenylethyl, and β-phenylpropyl; and 3,3,3- Examples thereof include monovalent substituted hydrocarbon groups such as a trifluoropropyl group and a chloromethyl group. Among these, a methyl group, a vinyl group, or a phenyl group is preferable from the viewpoint of ease of synthesis. Furthermore, when the organic group bonded to the silicon atom is a methyl group, the raw material is compared with the case of other organic groups. The intermediate is easy to synthesize, the viscosity is the lowest compared to the degree of polymerization of the resulting polymer, and the balance of physical properties of the rubber-like elastic body, which is a cured product, is most preferred. For this reason, it is most preferable that substantially all are methyl groups, but when the cured product requires heat resistance, it is preferable that some of the organic groups bonded to the silicon atom are phenyl groups. . Even when organic groups other than methyl groups are contained in this way, it is preferable that 85% or more of the total number of organic groups in the polymer is methyl groups for the reasons described above.

  Such polyorganosiloxane has a viscosity at 25 ° C. of 500 to 100,000 cSt, preferably 500 to 50,000 cSt. If the viscosity is less than 500 cSt, it is difficult to impart excellent mechanical properties to the cured product, and if it exceeds 100,000 cSt, the viscosity becomes too high and the workability is practically inferior.

  The component (B) is a long-chain alkyl group-containing silane compound represented by the following general formula.

R ¹ R ² _a Si (OR ³ ) _3-a
(In the formula, R ¹ represents an alkyl group having 5 to 20 carbon atoms, R ² represents a monovalent hydrocarbon, and R ³ represents an alkyl group. A is an integer of 0 or 1.)
R ¹ represents an alkyl group having 5 to 20 carbon atoms, and in order to exhibit the effects of the present invention, the alkyl group must have 5 or more carbon atoms, preferably an alkyl group having 6 to 18 carbon atoms. It is.

Examples of R ² include alkyl groups such as a methyl group, an ethyl group, and a propyl group, and monovalent hydrocarbon groups such as a phenyl group and a vinyl group.

Examples of R ³ generally include a methyl group, an alkyl group such as an ethyl group, and a propyl group because of the hydrolyzability of OR ³ . a is an integer of 0 or 1, preferably 0.

  Specific examples of the component (B) include octyltriethoxysilane, octylmethyldiethoxysilane, octyltrimethoxysilane, octylmethyldimethoxysilane, dodecyltriethoxysilane, dodecylmethyldiethoxysilane, dodecyltrimethoxysilane, dodecylmethyldimethoxy. Examples include silane, hexadecyltriethoxysilane, hexadecylmethyldiethoxysilane, hexadecyltrimethoxysilane, hexadecylmethyldimethoxysilane, and the like. These may be used alone or in combination of two or more.

  The amount of component (B) is 0.1 to 20 parts by weight per 100 parts by weight of component (A). When the amount is less than 0.1 part by weight, the crosslinking reaction is not sufficiently performed, and when the amount exceeds 20 parts by weight, an excessive crosslinking component that is not consumed by the crosslinking reaction adversely affects the properties of the rubber-like elastic body.

The reaction mixture of component (C) aminoalkylalkoxysilane and epoxyalkylalkoxysilane acts as a cross-linking agent for the composition of the present invention, and also functions to provide adhesion to various substrates that are in contact during curing. In addition, when used in combination with the component (B), the cured product of the composition of the present invention is imparted with adhesive durability under severe conditions such as immersion in warm water. Examples of the aminoalkylalkoxysilane constituting the component (C) include aminomethyltriethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) aminomethyltrimethyl. Examples include butoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-anilinopropyltriethoxysilane. Examples of the epoxyalkylorganoalkoxysilane include γ-glycidoxyprolyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3 , 4-epoxycyclohexyl) ethylmethyldimethoxysilane. These aminoalkylalkoxysilanes and epoxyalkylalkoxysilanes are mixed in a molar ratio of (1: 1.5) to (1: 5), preferably (1: 2) to (1: 4), and stored at room temperature or A reaction mixture can be easily obtained by heating. Component (C) is added in an amount of 0.1 to 20 parts by weight, preferably 0.5 to 10 parts by weight per 100 parts by weight of component (A). This is because if the amount of the component (C) is too small, sufficient rubber strength and adhesiveness cannot be obtained, and if it is too large, the curing rate is slowed down or the cured rubber becomes too hard.

  The component (D) curing catalyst serves as a catalyst for accelerating the curing of the composition of the present invention, and includes tin, titanium, zirconium, iron, antimony, bismuth or manganese organic carboxylates, organic titanates, and organic titanium chelates. Compound etc. are mentioned. Specific examples of the catalyst used include tin compounds such as dibutyltin dilaurate, dibutyltin dioctoate, dioctyltin dilaurate, dibutyltin malate ester, stannous octoate; tetrabutyl titanate, diisopropoxybis (acetylacetonate) Titanium compounds such as titanium and diisopropoxybis (ethyl acetoacetate) can be mentioned. Component (D) is added in an amount of 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight per 100 parts by weight of component (A). This is because if the amount of the component (D) is too small, the curing rate is too slow to be suitable for practical use, and if it is too large, the curing rate is too fast to take working time.

In the present invention, in order to impart excellent mechanical properties to the cured product, as the component (E), the BET specific surface area is 14.0 to 20.0 m ² / g, the average particle size is 0.05 to 0.20 μm, and the particle surface is treated with rosin acid. It is preferable to add the colloidal calcium carbonate prepared. When the average particle size is less than 0.05 μm, the viscosity becomes too high and the workability is practically inferior, and when it exceeds 0.20 μm, excellent mechanical properties cannot be imparted to the cured product. Can not be imparted to excellent mechanical properties in the cured product is less than even 14.0 m ² / g for the BET specific surface area, poor practical workability becomes too high viscosity exceeds 20.0 m ² / g. Further, calcium carbonate is a colloidal type, and the one whose surface is treated with rosin acid gives a rubber cured product having the highest modulus, and the resistance to warm and moisture and the warm water resistance are maintained.

  Examples of such calcium carbonate include Homocal D, Homocal DM, Shiroka Hana TDD, Shiroka Hana IGV (trade name, manufactured by Shiroishi Kogyo Co., Ltd.).

  The amount of component (E) is 10 to 200 parts by weight, preferably 50 to 150 parts by weight, per 100 parts by weight of component (A). If the amount is less than 10 parts by weight, excellent mechanical properties cannot be imparted to the cured product. If the amount exceeds 200 parts by weight, the viscosity becomes too high and the workability is practically inferior.

  In the composition of the present invention, an alkoxysilane different from the component (B) and the component (C) can be further added as a crosslinking agent in order to adjust the curability and rubber strength after curing. Examples of such alkoxysilanes include tetrafunctional silanes such as tetramethoxysilane, tetraethoxysilane, methyl cellosolve orthosilicate, and n-propyl orthosilicate; methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, vinyl Examples thereof include trifunctional alkoxysilanes such as trimethoxysilane, phenyltrimethoxysilane, and methyltrimethoxyethoxysilane, and partial hydrolysates thereof.

  Further, the composition of the present invention contains an organic solvent, a terminal trimethylsiloxylated diorganopolysiloxane, a flame retardant, a plasticizer, a thixotropic agent, a colorant, a normal adhesion promoter, an antifungal agent and the like as necessary. Addition may be made as long as the object of the present invention is not impaired.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the examples and comparative examples, “parts” all represent parts by weight.

Example 1
Collagen calcium carbonate “Shiraka Hana TDD” surface-treated with rosin acid with a BET specific surface area of 16.0 m ² / g and an average particle size of 0.10 μm on 100 parts of polydimethylsiloxane with a viscosity of 5,000 cSt blocked with silanol groups at both ends of the molecular chain 100 parts (product name, manufactured by Shiroishi Kogyo Co., Ltd.) were mixed until uniform (hereinafter, the obtained mixture is referred to as a base). On the other hand, each component shown in Table 1 was mixed and defoamed to obtain a catalyst composition. Subsequently, the base and the catalyst composition were mixed and removed at a ratio of 100: 5 (weight ratio) to obtain the composition of the present invention.

The hardness of this composition after 4 hours, 8 hours and 24 hours was examined. Further, the adhesion durability was evaluated by the following method.
<Method for evaluating adhesion durability of room temperature-curable organopolysiloxane composition>
An adhesion durability test specimen was prepared according to the method specified in JIS K5758 architectural sealant. That is, a room temperature-curable organopolysiloxane composition was filled between two float glass plates (float plate glass defined in JIS R3202) to prepare an adhesion durability test specimen (commonly known as an H-shaped test specimen). . The adhesion durability test specimen was allowed to stand for 7 days under conditions of a temperature of 23 ° C. and a humidity of 50% to cure the composition. The tensile adhesion strength of the obtained adhesion durability test specimen was measured, and the breaking state of the silicone rubber was observed together. Further, this adhesion durability test specimen was immersed in warm water of 80 ° C. for 14 days, then taken out, measured for tensile adhesive strength, and observed for the breaking state of the silicone rubber. These measurement results and observation results were expressed as follows.
M50: 50% tensile stress,
Tmax: Maximum tensile stress Emax: Elongation at maximum load CF: Cohesive failure (failed by silicone rubber layer)
TCF: Thin layer breakage (broken by leaving a thin layer of silicone rubber at the interface with the glass plate)
AF: Adhesive failure (peeling at the interface between glass plate and silicone rubber)

Examples 2-3 and Comparative Examples 1-5
A composition was obtained and evaluated in the same manner as in Example 1 except that the type and amount of each component to be blended were changed as shown in Table 1. The results are shown in Table 1.

Claims (1)

(A) 100 parts by weight of a polyorganosiloxane having molecular chain terminals blocked with silanol groups and having a viscosity at 25 ° C. of 500 to 100,000 cSt,
(B) 0.1-20 parts by weight of a long-chain alkyl group-containing silane compound represented by the following general formula,
R ¹ R ² _a Si (OR ³ ) _3-a
(In the formula, R ¹ represents an alkyl group having 8 to 20 carbon atoms, R ² represents a monovalent hydrocarbon, and R ³ represents an alkyl group. A is an integer of 0 or 1.)
(C) 0.1-20 parts by weight of a reaction mixture of aminoalkylalkoxysilane and epoxyalkylalkoxysilane ,
(D) a curing catalyst 0.001 to 10 parts by weight , and
(E) Room temperature curable organo, characterized in that it contains 50 to 200 parts by weight of rosin acid-treated colloidal calcium carbonate having a BET specific surface area of 14.0 to 20.0 m ² / g and an average particle size of 0.05 to 0.20 μm. Polysiloxane composition.