JPH06157910A - Room temperature curable polyorganosiloxane composition - Google Patents

Abstract

PURPOSE:To obtain a room temperature curable composition useful as a sealing material for building construction, having matted surface and excellent storage stability, comprising a specific polyorganosiloxane, a specific organosilicon compound, specific mica powder, specific calcium carbonate and a specified condensation reaction catalyst in a specific ratio. CONSTITUTION:This curable composition comprises (A) 100 pts.wt. substantially straight-chain polyorganosiloxane having 20-1,000,000 centistokes viscosity at 25 deg.C, containing a molecular chain end hindered with silanol group or silicon atom bond-hydrolyzable group, (B) 0.1-15 pts.wt. organosilicon compound containing three or more silicon atom bond-hydrolyzable groups in one molecule, (C) 0-10 pts.wt. reaction catalyst such as dibutyltin dilaurate, (D) 10-100 pts.wt. diatomaceous earth having >=0.5mum average particle diameter and/or mica powder having >=0.5mum average particle diameter and (E) 10-150 pts.wt. colloidal calcium carbonate having <=1mum average particle diameter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a room temperature curable polyorganosiloxane composition, and more particularly to a room temperature curable polyorganosiloxane composition capable of becoming a silicone rubber having a matte surface after curing at room temperature. Regarding things.

[0002]

2. Description of the Related Art Conventionally, there are various types of room temperature-curable polyorganosiloxane compositions which are cured at room temperature to form a rubber-like elastic body by contact with moisture in air. Are known. Among these, the type that releases alcohol to cure is used as a sealing material for construction and adhesives because it has no unpleasant odor and is not corrosive to metals. It is used as an adhesive, coating, and sealing material for equipment. In addition, the type that releases oxime and cures is widely used for architectural purposes because of its excellent storage stability and less unpleasant odor. However, since the surface of these compositions has gloss after curing, it is not suitable for the atmosphere when used as an adhesive or a sealing material applied to various materials having a matte surface. It is said that it cannot be used for such purposes. Therefore, the advent of a room temperature curable polyorganosiloxane composition that can become a silicone rubber having a matte surface after curing has been desired.

[0003]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have found that if a room temperature curable polyorganosiloxane composition is blended with a specific filler, the surface after curing is The present invention has been completed by finding that the gloss can be suppressed and the physical properties thereof can be maintained.
That is, it is an object of the present invention to provide a room temperature curable polyorganosiloxane composition which can be a silicone rubber having a matte surface after curing at room temperature.

[0004]

Means for Solving the Problem and Its Action The present invention provides (A) a viscosity at 25 ° C. of 20 to 1,000,000 centistokes and a molecular chain end blocked with a silanol group or a silicon atom-bonded hydrolyzable group. Substantially linear polyorganosiloxane 100 parts by weight, (B) organosilicon compound having 3 or more silicon atom-bonded hydrolyzable groups in one molecule, 0.1 to 15 parts by weight, (C) condensation Reaction catalyst 0 to 10 parts by weight, (D) diatomaceous earth having an average particle size of 0.5 μm or more and / or mica powder having an average particle size of 0.5 μm or more 10 to 100 parts by weight, and (E) an average particle size of 1 μm or less It relates to a room temperature curable polyorganosiloxane composition comprising 10 to 150 parts by weight of colloidal calcium carbonate.

The polyorganosiloxane of the component (A) used in the present invention is a substantially linear polyorganosiloxane in which the molecular chain end is blocked with a silanol group or a silicon atom-bonded hydrolyzable group. Here, “substantially linear” means not only a completely linear but also a slightly branched linear one. Examples of the silicon atom-bonded hydrolyzable group present at the terminal of the molecular chain of this polyorganosiloxane include alkoxy groups such as methoxy group, ethoxy group and propoxy group, oxime groups such as methylethylketoxime group and dimethylketoxime group, and isopropenoxy group. Examples include alkenyloxy groups such as groups, as well as trimethoxysilylpropyl groups. Further, other silicon atom-bonded organic groups present in this polyorganosiloxane include alkyl groups such as methyl group, ethyl group, propyl group, butyl group and octyl group; vinyl group, allyl group and hexenyl group. Alkenyl group; aryl group such as phenyl group and tolyl group; benzyl group; substituted alkyl group such as 3,3,3-trifluoropropyl group, 3-chloropropyl group, 3-cyanopropyl group and chloromethyl group It is illustrated. When the viscosity of this polyorganosiloxane is too low, the rubber elasticity of the cured sealant becomes poor, and when the viscosity is too high, the extrudability becomes heavy and the discharge work from a container such as a cartridge becomes difficult. ~ 1,000,000
Must be within 0 centistokes,
Desirably, it is in the range of 100 to 100,000 centistokes.

The component (B) organosilicon compound used in the present invention is a component which acts as a crosslinking agent for the present composition and crosslinks and cures the present composition. This organosilicon compound is an organosilicon compound having three or more silicon atom-bonded hydrolyzable groups in one molecule. The silicon atom-bonded hydrolyzable group is preferably the same as the silicon atom-bonded hydrolyzable group in the component (A). Such a hydrolyzable group is described in the section of the description of the component (A). The alkoxy group, the alkenyloxy group and the oxime group are mentioned above, and the alkoxy group and the oxime group are particularly preferable. Examples of the organosilicon compound having an alkoxy group include trifunctional alkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, phenyltrimethoxysilane, and vinyltrimethoxysilane, and partial hydrolyzed condensates thereof, methyl orthosilicate, ethyl. Alkyl silicates such as orthosilicate, n-propyl orthosilicate, and methyl cellosolve silicate and their partial hydrolysis-condensation products,

[Chemical 1] Cyclic alkoxy siloxanes such as

[Chemical 2]

[Chemical 3] Examples thereof include linear alkoxysiloxanes. Examples of the organosilicon compound having an alkenyloxy group include methyltriisopropenoxysilane, vinyltriisopropenoxysilane, phenyltriisopropenoxysilane, tetraisopropenoxysilane, methyltricyclohexenoxysilane, vinyltricyclohexenoxy. Examples thereof include alkenyloxysilanes such as silane and partially hydrolyzed condensates thereof. As the organosilicon compound having an oxime group,

[Chemical 4]

[Chemical 5]

[Chemical 6]

[Chemical 7] Examples thereof include oxime silanes such as CH ₂ ═CHSi [ON═C (CH ₃ ) ₂ ] ₃ and partial hydrolysis-condensation products thereof. These organosilicon compounds may be used alone or in combination of two or more. Moreover, you may use the organosilicon compound which has a several hydrolyzable group in 1 molecule. The amount of component (B) added is in the range of 0.1 to 15 parts by weight, preferably 0.5 to 10 parts by weight, per 100 parts by weight of component (A). This is because the composition does not cure when the amount of component (B) added is less than 0.1, and
This is because if it exceeds 5 parts by weight, the curing will be delayed and it will be economically disadvantageous.

The condensation reaction catalyst of the component (C) used in the present invention is optionally used to accelerate the curing of the composition of the present invention. Examples of this type of catalyst include organic acid salts of tin, titanium, zirconium, iron, antimony, bismuth, manganese, etc., organic titanate esters, and organic titanium chelate compounds. Specific examples of such condensation reaction catalysts include organic tin compounds such as dibutyltin dilaurate, dibutyltin dioctoate and stannas octoate, tetrabutyl titanate, tetraisopropyl titanate, diisopropoxybis (acetylacetonate) titanium, dibutyltin dioctoate. An organic titanium compound such as isopropoxybis (ethylacetoacetate) titanium is exemplified. Here, when the component (B) is vinyltrioxime silane, the component (C) is unnecessary. The amount of this component added is
0 to 15 parts by weight per 100 parts by weight of component (A),
A range of 0.001 to 5 parts by weight is preferable.

The component (D), diatomaceous earth and / or mica powder, is a component which characterizes the present invention, and acts to give a cured product of the composition of the present invention a matte surface. still,
In the composition of the present invention, the diatomaceous earth and the mica powder each give a matte surface, but when they are used in combination, a further excellent matteness is exhibited. The addition amount of this component is 10 to 1 with respect to 100 parts by weight of the component (A).
If the amount is too small, the matteness is insufficient, and if the amount is too large, the extrudability before curing and the adhesiveness / mechanical strength are adversely affected.

The (E) component colloidal calcium carbonate is
It is an essential component for imparting good physical properties and good adhesion to the composition of the present invention. That is, the diatomaceous earth and / or mica powder as the component (D) can provide the surface mattability, but the component (D) alone cannot provide the required physical properties and adhesiveness. As well known to those skilled in the art, calcium carbonate is a heavy calcium carbonate,
There are light calcium carbonate, colloidal calcium carbonate, etc., but only the colloidal calcium carbonate having the smallest particle size can be used in the composition of the present invention. The presence or absence of surface treatment of calcium carbonate is not particularly limited, but those treated with fatty acid, resin acid, surfactant and the like are preferable, and those treated with fatty acid and resin acid are particularly preferable. This component is 10 to 150 parts by weight with respect to 100 parts by weight of the component (A). If it is too small, adhesiveness and mechanical strength are insufficient, and if it is too large, it has matte properties and extrudability from a container before curing. Adversely affect.

The composition of the present invention comprises the above-mentioned components (A) to (E) or components (A), (B), (D) and (E).
It can be easily produced by uniformly mixing the components. In addition to these components, organic solvents, fluidity control agents, fungicides, flame retardants, heat resistance agents, adhesion promoters, pigments,
Addition of an inorganic filler other than the component (D) and the component (E), a component for imparting conductivity, etc. may be added unless the object of the present invention is impaired.

[0011]

EXAMPLES The present invention will be described below with reference to examples. In the examples, the viscosity is a value at 25 ° C., and cs represents centistokes. In the examples, various properties of the room temperature curable polyorganosiloxane composition were measured according to the following methods. ○ Measurement of Physical Properties A room temperature curable polyorganosiloxane composition was placed in a mold and allowed to stand for 7 days under the conditions of 20 ° C. and 55% humidity to be cured to form a 2 mm thick silicone rubber sheet. . Physical properties of this silicone rubber sheet
It was measured according to ISK6301. The hardness is JIS A
I used a mold hardness tester. -Measurement of gloss value The silicone rubber sheet used for the measurement of physical properties was placed in a gloss measuring machine, and the surface was irradiated with light under the condition of an incident angle of 60 degrees. The gloss value was measured from the light reflection degree (light reflectance). However, the gloss value of glass having a reflectance of 10% and a refractive index of 1.567 was set to 100. Here, the smaller the value of gloss, the less gloss. -Adhesiveness A room temperature curable polyorganosiloxane composition was extruded in the shape of a string on the surface of each test plate and left standing for 7 days to cure at 20 ° C and 50% humidity. After that, the cord-like cured product was manually peeled off from the tensile test plate. At this time, the fractured state at the interface between the cured product and the test plate was visually observed.

[0012]

Example 1 100 parts by weight of polydimethylsiloxane blocked with silanol groups at both ends having a viscosity of 15,000 cs, surface fatty acid-treated colloidal calcium carbonate (average particle size 0.1 μm)
m) 60 parts by weight, diatomaceous earth (average particle size 5 μm) 20 parts by weight, mica powder (average particle size 5 μm) 20 parts by weight, methyltrimethoxysilane 5 parts by weight, diisopropoxybis (ethylacetoacetate) titanium 2 parts by weight Were mixed to prepare a one-pack type room temperature curable polyorganosiloxane composition. The gloss, adhesion and physical properties of this composition were measured. The results are shown in Table 1.

[0013]

Example 2 100 parts by weight of polydimethylsiloxane blocked with silanol groups at both ends and having a viscosity of 15,000 cs, surface fatty acid-treated colloidal calcium carbonate (average particle size 0.1 μm)
m) 60 parts by weight, diatomaceous earth (average particle size 5 μm) 40 parts by weight, methyltrimethoxysilane 5 parts by weight, and diisopropoxybis (ethylacetoacetate) titanium 2 parts by weight are mixed to form a one-pack type room temperature curable polyorgano. A siloxane composition was prepared. The gloss, adhesion and physical properties of this composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[0014]

Example 3 100 parts by weight of polydimethylsiloxane blocked with methyldimethoxysiloxy groups at both ends having a viscosity of 15,000 cs, 60 parts by weight of surface fatty acid-treated colloidal calcium carbonate (average particle size 0.1 μm), mica powder (average particle size) 5 μm) 40 parts by weight, methyltrimethoxysilane 5 parts by weight, diisopropoxybis (ethylacetoacetate)
Two parts by weight of titanium were mixed to prepare a one-pack type room temperature curable polyorganosiloxane composition. The gloss, adhesion and physical properties of this composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[0015]

Example 4 100 parts by weight of polydimethylsiloxane capped with silanol groups at both ends having a viscosity of 10,000 cs, surface fatty acid-treated colloidal calcium carbonate (average particle size 0.1 μm)
m) 60 parts by weight, diatomaceous earth (average particle size 5 μm) 20 parts by weight, mica powder (average particle size 5 μm) 20 parts by weight, methyltri (methylethylketoxime) silane 15 parts by weight,
A one-part room temperature curable polyorganosiloxane composition was prepared by mixing 0.5 part by weight of dibutyltin dilaurate and 2 parts by weight of γ-aminopropyltrimethoxysilane. The gloss, adhesion and physical properties of this composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[0016]

[Comparative Example 1] 100 parts by weight of polydimethylsiloxane blocked at both ends with silanol groups having a viscosity of 15,000 cs, surface fatty acid-treated colloidal calcium carbonate (average particle size: 0.1 μm)
m) 100 parts by weight, 5 parts by weight of methyltrimethoxysilane, diisopropoxybis (ethylacetoacetate)
Two parts by weight of titanium were mixed to prepare a one-pack type room temperature curable polyorganosiloxane composition. The gloss, adhesion and physical properties of this composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[0017]

Comparative Example 2 100 parts by weight of polydimethylsiloxane blocked with silanol groups at both ends and having a viscosity of 10,000 cs, 10 parts by weight of fumed silica (average particle size 0.01 μm), 15 parts by weight of methyltris (methylethylketoxime) silane, dibutyltin dilaurylate. 0.5 parts by weight were mixed to prepare a one-part room temperature curable polyorganosiloxane composition.
The gloss, adhesion and physical properties of this composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[0018]

[Comparative Example 3] 100 parts by weight of polydimethylsiloxane blocked with silanol groups at both ends having a viscosity of 15,000 cs, 70 parts by weight of diatomaceous earth (average particle size 5 μm), 70 parts by weight of mica powder (average particle size 5 μm), methyltrimethoxysilane 5 Parts by weight, diisopropoxy bis (ethyl acetoacetate)
Two parts by weight of titanium were mixed to prepare a one-pack type room temperature curable polyorganosiloxane composition. The gloss, adhesion and physical properties of this composition were measured in the same manner as in Example 1. The results are shown in Table 1.

[Table 1] ○ Adhesiveness is good; cohesive failure (broken at the silicone rubber layer). △ Adhesiveness is intermediate between cohesive failure and interfacial failure. × Poor adhesion: Interface failure (fractured at the interface between the silicone rubber layer and the adherend).

[0019]

The room temperature-curable polyorganosiloxane composition of the present invention comprises components (A) to (E), or components (A), (B), (D) and (E). , Especially (D)
Since it contains diatomaceous earth with an average particle size of 0.5 μm or more and / or mica powder with an average particle size of 0.5 μm or more, it can be a silicone rubber having a matte surface after curing at room temperature. It has characteristics.

Claims (1)

[Claims] 1. (A) The viscosity at 25 ° C. is 20 to 1.0
100 parts by weight of a substantially linear polyorganosiloxane having a molecular chain end blocked with a silanol group or a silicon atom-bonded hydrolyzable group, (B) a silicon atom bond in one molecule Organosilicon compound having 3 or more hydrolyzable groups 0.1 to 15 parts by weight, (C) condensation reaction catalyst 0 to 10 parts by weight, (D) diatomaceous earth having an average particle size of 0.5 μm or more and / or an average particle size A room-temperature-curable polyorganosiloxane composition comprising 10 to 100 parts by weight of 0.5 μm or more of a mica powder, and (E) 10 to 150 parts by weight of colloidal calcium carbonate having an average particle size of 1 μm or less.