JPS61296064A - Polyorganosiloxane composition reinforced with inorganic fine powder - Google Patents

Abstract

PURPOSE:To provide the titled composition formable to a thin film and having excellent electrical insulation property, moisture resistance, water resistance, chemical resistance and mechanical properties, by compounding a polyorganosiloxane resin with a phosphoric acid compound and fine mica powder. CONSTITUTION:The objective composition can be produced by compounding (A) 100pts.(wt.) of a polyorganosiloxane resin composed of the organosiloxane unit of formula I (R<1> is univalent hydrocarbon group, preferably methyl; R<2> is H or univalent hydrocarbon group; a is 1-1.5; b is 0.05-0.2) and curable by the condensation reaction of the group selected from hydroxyl group and alkoxy group with (B) <=10pts. of a phosphoric acid compound selected from phosphoric acid and the compound of formula II (R<3> is substituted or unsubstituted univalent hydrocarbon group; c is 1 or 2), (C) 10-150pts. (based on 100pts. of A+B) of fine mica powder, and preferably (D) 0.1-10pts. (based on 100pts. of the component A) of carbon-functional organic silicon compound and (E) 1-10pts. (based on the solid component) of bentonite in the form of solution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inorganic fine powder reinforced silicone resin composition. In particular, the present invention relates to an inorganic fine powder-reinforced silicone resin composition that can be formed into a thin film and has excellent electrical insulation, mechanical strength, moisture resistance, water resistance, chemical resistance, and heat resistance.

Silicone resins have excellent properties and are used for various purposes. For example, silicone resin alone
Alternatively, it can be used as a paint by blending heat-resistant inorganic pigments such as silica, magnesia, and titanium oxide. Although the coating films formed with these exhibit excellent heat resistance, they do not necessarily exhibit sufficient performance in terms of F# moisture resistance, water resistance, chemical resistance, and mechanical strength. In particular, known silicone resins have not been able to provide satisfactory moisture resistance and corrosion resistance (acid, alkali, salt water, etc.) when forming a thin film of 10 μm or less as a protective coating for metal.

The present invention provides an inorganic fine powder-reinforced polyorganosiloxane composition that can be applied as a thin film onto a metal substrate and has excellent electrical insulation, moisture resistance, water resistance, chemical resistance, and mechanical properties. .

According to the present invention, a is a monovalent group selected from the general formula and a monovalent hydrocarbon group, and a is 1.
0-1.5. 100 parts by weight of a polyorganosiloxane resin cured by a condensation reaction of a monovalent group selected from the group consisting of a hydroxyl group and an alkoxy group at the center of the organosiloxane represented by S (b represents 0.05 to 0.2); 10 parts by weight or less of phosphoric acid and the general formula % ster (wherein R3 is a substituted or unsubstituted monovalent hydrocarbon group,
10-150 parts by weight of fine mica powder are blended with 100 parts by weight of a mixture of the polyorganosiloxane resin and the phosphoric acid compound (C represents 1 or 2). An inorganic fine powder reinforced polyorganosiloxane composition is provided.

In the present invention, since the polyorganosiloxane resin is cured by a condensation reaction of monovalent groups selected from the group consisting of hydroxyl groups and alkoxy groups, substantially all of the organic groups bonded to silicon atoms are methyl groups, and the number of However, it is preferably 1.0 to 1.2 per silicon atom.

Phosphate esters preferably used in the present invention include:
(CH30)P(0)(CH)2, (CH30)P
(0)(OH), (C2H50)P(0)(OH)
(CH0)2F(0)2' 2 5 (OH), etc.

The fine mica powder has a particle size of 200 ILm or less and an aspect ratio (ratio of mica piece diameter/mica piece thickness) of lO
Muscovite-based or flocovite-based mica is used.

The carbon-functional organosilicon compound is preferably one in which the carbon functional group is a monovalent group selected from organic groups including a vinyl group, an amine group, a methacryloxy group, or an epoxy group. Examples of these include vinyltriethoxysilane, vinyltris(2-methoxyethoxysilane), γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxy Silane, N-β-(aminoethyl)
-γ-aminopropyltriethoxysilane, β-(3,
4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ
-metacycloxypropyltrimethoxysilane and polysiloxane obtained by hydrolyzing these.

These compounds are polyorganosiloxane resin 100
It is added at a blending ratio of 0.1 to 10 parts by weight.

In order to improve the solubility of phosphoric acid or phosphoric acid ester in polyorganosiloxane resin, it is recommended to dissolve it in advance in a mixed solvent such as toluene or xylene containing 20 wt% or more of alcohol such as propyl alcohol or butyl alcohol. good.

The phosphoric acid or phosphate ester and the carbon-functional organosilicon compound may be added separately to the polyorganosiloxane resin, or they may be added as a premix to the polyorganosiloxane resin.

Bentonite prevents the settling of fine mica powder in the coating solution11.
For this purpose, 1 to 10 parts by weight based on the solid content is used, and a solution is added to this.

Next, preferred embodiments of the present invention will be described.

Example 1 Toshiba Silicone TSR-127B (polyorganosiloxane resin with one methyl group) 360 weight 31 parts (solid content 50%) and 1000 mesh (particle size 13 μm) muscovite mica 90 weight with aspect ratio 20 A premixed mixture of 4.3 parts by weight of phosphoric acid and 0.2 parts by weight of γ-glycidoxypropyltrimethoxysilane as a stabilizer was added to the mixture, and further, mica powder was precipitated. Defense 1
1-A paint preparation was made by adding 84 parts by weight of bentonite liquid (7 parts of organic bentonite, 70 parts of toluene, 7 parts of isopropyl alcohol) as an agent, and the resulting coating liquid was homogenized for 3 hours with a homo mixer. It was applied to a steel plate with a thickness of 3 #i, m using the dip coating method, and after the paint was air-dried, it was heated to 200°C in an oven! The coating film was cured by leaving it for 3 hours.

Various physical properties of the coating film obtained in Example 1 were measured. The results are shown in Table 1.

Examples 2 and 3 Except that the amount of mica powder was 270 parts and 18 parts,
Table 2 shows the physical properties of the coating film obtained by performing the same operation as in Example 1.

The phosphoric acid or phosphoric acid ester used in the present invention has a catalytic function to rapidly cure the polyorganosiloxane resin, and improves the water resistance, chemical resistance, and adhesion of the coating film of the inorganic fine powder reinforced polyorganosiloxane composition. Direction-1-
useful for.

For comparison, a physical property test was conducted on a coating film obtained in the same manner as in Example 1 except that phosphoric acid or phosphoric acid ester was not added. The results are shown in Table 3.

As is clear from the comparison of Tables 1 and 3, the composition according to the present invention containing phosphoric acid or phosphoric acid ester has remarkable improvements in curability, electrical insulation, adhesion, chemical resistance, etc. be.

As mentioned above, the inorganic fine powder reinforced polyorganosiloxane composition for metal protection according to the present invention can be applied as a thin film of 10 #Lm or less, and has excellent electrical insulation, moisture resistance, water resistance, and chemical resistance. It also has excellent mechanical strength such as flexibility, impact resistance, and abrasion resistance.

Claims (4)

[Claims] (1) General formula R^1_asi(OR^2)bO(4-a-b)/2(
In the formula, R^1 is a monovalent hydrocarbon group, R^2 is hydrogen and 1
a monovalent group selected from valent hydrocarbon groups, a is 1.0 to 1
．． 5, b represents 0.05 to 0.2) 100 parts by weight of a polyorganosiloxane resin that is cured by a condensation reaction of a monovalent group selected from the group consisting of a hydroxyl group and an alkoxy group; 10 parts by weight or less of phosphoric acid and a phosphoric acid ester of the general formula (R^3O)_CP(O)(OH)_3_-_C (wherein R^3 is a substituted or unsubstituted monovalent hydrocarbon group, C is 1 or 2), and 10 to 150 parts by weight of mica fine powder are blended with 100 parts by weight of the mixture of the polyorganosiloxane resin and the phosphoric acid compound. An inorganic fine powder reinforced polyorganosiloxane composition. (2) Claim 1, wherein R^1 is a methyl group
Compositions described in section (3) 0 parts by weight of a carbon-functional organosilicon compound selected from an organoalkoxysilane having a carbon-functional group and a polyorganosiloxane obtained by hydrolyzing the organoalkoxysilane to 100 parts by weight of the polyorganosiloxane resin. .1 to 10 parts by weight of the composition according to claim 1. (4) The composition according to claim 3, which contains 1 to 10 parts by weight of bentonite.