JP3022124B2 - Room temperature curable organopolysiloxane composition - Google Patents

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 organopolysiloxane composition useful as a building material in the construction industry.

[0002]

2. Description of the Related Art Room temperature-curable organopolysiloxane compositions have been applied to various fields including the construction industry since the resulting cured products have properties such as weather resistance and heat resistance. In recent years, in the field of the construction industry, emphasis has been placed on the appearance of cured products, in addition to such properties. However, in the case of a room temperature-curable organopolysiloxane composition, the surface energy of the organopolysiloxane, which is the main component, is low, and the surface of the resulting cured product is only glossy with a commonly used composition. Therefore, such compositions could not be used where a matte surface was required.

Accordingly, as a technique for preparing a room-temperature-curable organopolysiloxane composition that gives a cured product having a matte surface, a technique has been proposed in which a large amount of an inorganic filler having coarse particles is contained in the composition. However, this has disadvantages such as an increase in the specific gravity of the obtained composition, a remarkable decrease in the extrudability of the composition, and a decrease in mechanical properties such as elongation of the obtained cured product. Due to this drawback, the composition obtained by this technique has been applied only to limited uses, although the cured product obtained has a matte surface.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a room temperature curable organopolysiloxane composition which has a specific gravity which is not particularly large and which gives a cured product having a matte surface while having good mechanical properties. It is to provide.

[0005]

The present invention solves the above-mentioned problems by providing (a) 100 parts by weight of a diorganopolysiloxane in which both ends of a molecular chain are terminated by hydroxyl groups, and (b) silicon in one molecule. At least one selected from the group consisting of an organic silicon compound having at least three hydrolyzable groups bonded to a silicon atom and a partial hydrolyzate thereof; 0.5 to 30 parts by weight; (c) inorganic filler 1 to 500 The present invention provides an organopolysiloxane composition comprising, by weight, 0.1 to 20 parts by weight of a fibrous resin having a fiber length of 0.01 to 0.5 mm. Hereinafter, the present invention will be described in detail.

(A) Component As the component (a), for example, the following general formula (1): (Wherein R ¹ may be the same or different and is a substituted or unsubstituted monovalent hydrocarbon group, and n is an integer of 10 or more). In the general formula (1), examples of the substituted or unsubstituted monovalent hydrocarbon group R ¹ include an alkyl group such as a methyl group, an ethyl group and a propyl group; a cycloalkyl group such as a cyclohexyl group; a vinyl group and an allyl group Alkenyl group such as phenyl group, tolyl group and the like; groups in which hydrogen atoms of these hydrocarbon groups are partially substituted by halogen atoms such as fluorine and the like.

The viscosity of the organopolysiloxane is 2
It is preferably within the range of 25 to 500,000 cSt at 5 ° C, more preferably 1,000 to 10 at 25 ° C.
It is in the range of 000 cSt.

(B) Component The organosilicon compound as the component (b) includes, for example, silane, siloxane and the like. Examples of the hydrolyzable group contained in the organosilicon compound include, for example, a methoxy group,
An alkoxy group such as an ethoxy group; a ketoxime group such as a dimethyl ketoxime group and a methyl ethyl ketoxime group;
Acyloxy groups such as acetoxy group; amino groups such as N-butylamino group and N, N-diethylamino group; amide groups such as N-methylacetamide group; N, N-dimethylaminooxy group and N, N-diethylaminoxy group And an alkenyloxy group such as an isopropenoxy group, an isobutenoxy group and a cyclohexenoxy group.

Specific examples of the organosilicon compound include:
Alkoxysilanes such as methyltrimethoxysilane, vinyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-aminopropyltriethoxysilane,
Ketoxime silanes such as methyltris (dimethylketoxime) silane, methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane, tetra (methylethylketoxime) silane, vinyltriacetoxysilane, methyltriacetoxysilane, phenyltriacetoxysilane, etc. Acyloxysilane, phenyltris (N-methylacetamido) silane, vinyltris (N-methylacetamido)
Amidosilanes such as silane, aminosilanes such as vinyltris (N-butylamino) silane and phenyltris (N, N-diethylamino) silane, methyltris (N, N-
Dimethylaminoxy) silane, vinyl tris (N, N-
Aminooxysilanes such as diethylaminoxy) silane,
Alkenyloxysilanes such as vinyltriisopropenoxysilane, methyltriisobutenoxysilane, and phenyltricyclohexanoxysilane are exemplified. These organosilicon compounds and partial hydrolysates thereof may be used alone or in combination of two or more.

The amount of the component (b) is 0.5 to 30 parts by weight, preferably 3 to 20 parts by weight, per 100 parts by weight of the component (a). If this amount is less than 0.5 part by weight, the composition may gel during the preparation of the composition or during storage of the composition, or the curing of the elastic body obtained by curing the composition may not be achieved sufficiently. The mechanical strength is reduced. On the other hand, when the amount exceeds 30 parts by weight, the shrinkage of the composition at the time of curing becomes large, and the elasticity of the obtained cured product decreases.

Component (c) The component (c) may be an inorganic filler usually added to a room temperature-curable organopolysiloxane composition.
Examples include fumed silica, wet silica, colloidal calcium carbonate, heavy calcium carbonate, zinc carbonate, carbon black, titanium dioxide, aluminum oxide, quartz powder, talc, bentonite and the like. The surface of these inorganic fillers may be subjected to a hydrophobic treatment with hexamethyldisilazane or a treatment with stearic acid soap.

The amount of the component (c) is 1 to 500 parts by weight, preferably 10 to 300 parts by weight, per 100 parts by weight of the component (a).
Parts by weight. If the amount is less than 1 part by weight, the elastic body obtained by curing the composition will not exhibit practically usable mechanical strength. If it exceeds 500 parts by weight, the elastic body becomes brittle.

(D) Component The component (d) may be any fibrous resin as long as it is inert to each component in the composition.
Examples include fibrous resins made of polyethylene, polypropylene, polyester, nylon, tetron and the like.

The fiber length of the component (d) is 0.01 to 0.5 mm
Must be within the range. This fiber length is 0.0
If it is less than 1 mm, the surface of the obtained cured product cannot be sufficiently matted. On the other hand, when the thickness exceeds 0.5 mm, mechanical properties such as elongation are extremely reduced, and the appearance of the cured product is impaired.

The amount of the component (d) is 0.1 to 20 parts by weight, preferably 0.5 to 1 part by weight, per 100 parts by weight of the component (a).
0 parts by weight. If this amount is less than 0.1 parts by weight,
The surface of the obtained cured product cannot be sufficiently matted. Also, if it exceeds 20 parts by weight, the tensile strength,
The mechanical properties such as elongation are extremely reduced, and the appearance of the cured product is impaired.

Other Additives The organopolysiloxane composition of the present invention may contain , if necessary, known additives usually added to the condensation-curable room temperature-curable organopolysiloxane composition, such as amines, Curing catalysts such as organic metal compounds such as quaternary ammonium salts and dibutyltin dioctoate, titanium chelate compounds, and guanidyl group-containing compounds [usually, component (a) 100
0.05 to 10 parts by weight per part by weight]; an oil-resistance improving agent such as potassium methacrylate; a coloring agent; a heat resistance improving agent such as red iron oxide and cerium oxide; a cold resistance improving agent; a thixotropic agent such as polyether; An adhesiveness improver such as γ-aminopropyltriethoxysilane may be added.

Preparation of Composition The composition of the present invention can be prepared , for example, by mixing a predetermined amount of the components (a) to (d) uniformly in a dry (ie, anhydrous) atmosphere to form a one-part composition. It is prepared as Also, for example,
A homogeneous mixture of the components (a), (c) and (d) and the component (b) may be prepared as a two-pack type composition separately packaged.
When the composition of the present invention is exposed to the atmosphere, the composition is cured by moisture in the atmosphere.

Applications The room-temperature-curable organopolysiloxane composition of the present invention is required to have design properties used for, for example, sealants used in places where the appearance of building materials is important, food samples, and the like. It is useful as a material.

[0019]

Examples of the present invention will be described below. In each example, “parts” indicates “parts by weight”, and the viscosity is a measured value at 25 ° C. In the following description, * was added to the number of the composition according to the comparative example. Compositions without an asterisk (*) are examples of the present invention.

Example 1 100 parts of dimethylpolysiloxane (viscosity: 20,000 cSt) in which both ends of a molecular chain are terminated with a hydroxyl group, and 13 parts of hydrophobic silica obtained by hydrophobizing the surface of fumed silica with hexamethyldisilazane , And 1.5 parts of titanium dioxide. After passing the obtained mixture through a three-roll mill once, the mixture was further added with methyltributanoxime silane 7
, 5 parts by weight of polyethylene fiber having a fiber length of 0.3 mm and 0.1 part of dibutyltin dioctoate were defoamed and mixed in an anhydrous state to prepare composition 1.

Example 2 Colloidal calcium carbonate 6 whose surface was treated with a stearic acid soap on 100 parts of dimethylpolysiloxane (viscosity: 20,000 cSt) in which both ends of a molecular chain were terminated with a hydroxyl group
0 parts and 1.5 parts of titanium dioxide were mixed. After passing the obtained mixture through a three-roll mill once, 7 parts of methyltributanoxime silane and a fiber length of 0.1 were further added to the mixture.
10 parts by weight of polyester fiber of 0.1 mm and 0.1 part of dibutyltin dioctoate are defoamed and mixed in an anhydrous state,
Composition 2 was prepared.

Comparative Example 1 A composition 3 ^* was prepared in the same manner as in Example 1 except that polyethylene fiber was not blended.

Comparative Example 2 A composition 4 ^* was prepared in the same manner as in Example 2 except that no polyester fiber was blended. The compositions 1-4 ^* were formed into a sheet having a thickness of 2 mm, and the obtained sheet was heated at a temperature of 20
When left in an atmosphere at a temperature of 55 ° C. and a relative humidity of 55% for 7 days, all of these sheets were cured to become rubber elastic bodies. The surface of the obtained rubber elastic body was observed, and whether or not the surface was matte was observed. The physical properties of the rubber elastic body were measured in accordance with JIS K6301 (the hardness was measured using a spring-type hardness tester type A). Table 1 shows the results.

[0024]

[Table 1]

[0025]

The room-temperature-curable organopolysiloxane composition of the present invention has a specific gravity which is not particularly high, and gives a cured product having good mechanical properties and a matte surface.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 83/06

Claims (1)

(57) [Claims] (1) 100 parts by weight of a diorganopolysiloxane having both ends of a molecular chain terminated by a hydroxyl group, and (b) a compound having at least three hydrolyzable groups bonded to a silicon atom in one molecule. At least one selected from the group consisting of a silicon compound and a partial hydrolyzate thereof, 0.5 to 30 parts by weight, (c) 1 to 500 parts by weight of an inorganic filler, and (d) a fiber length of 0.01 to 0. 0.1 to 20 parts by weight of a fibrous resin having a diameter of 0.5 mm, containing no water and hardening by absorbing moisture.
A room temperature curable organopolysiloxane composition which can be converted into a composition.