Polysiloxane composition and method of making the same

PATENT DESCRIPTION 148 704

POLAND

REPUBLIC

CHINA

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Additional patent to patent no. - Patent pending: 86 11 18 (P. 262455)

Int. Cl.4 C08L 8/04

First - CZ '5LLNIA

OFFICE

PATENT

PRL

The application was announced: 88 08 04

Patent description published: 1990 03 31

Inventor: Jeremi Maciejewski

Patent holder: Institute of Industrial Chemistry, Warsaw (Poland)

Polysiloxane composition and method for preparing the polysiloxane composition

The present invention relates to a polysiloxane composition and a method for preparing the polysiloxane composition used to impregnate waterproof porous materials, for the production of coatings with high adhesion to metals and silicone elastomers, and as an adhesive in the processing of chemosetting resins.

Known polysiloxane compositions used for waterproofing, as coating materials or as release agents are most often solutions of cross-linked polysiloxane polymers obtained by the hydrolysis of mixtures of alkyl- or alkyl-arylchlorosilanes. The polysiloxane composition known from the description of Polish patent No. 49 957 for hydrophobization and protective enamels is obtained by hydrolysis of a mixture of methyl-trichlorosilane with dimethyl-dichlorosilane in water with the addition of alcohol.

The method of obtaining the composition according to the description No. 49 957 consists in hydrolyzing a solution of chlorosilanes dissolved in organic solvents in water containing alcohols and separating the organic layer constituting the solution of the polysiloxane composition.

Also known is the polysiloxane composition from Polish Patent No. 88 964 used as an adhesive and being a mixture of a polysiloxane resin with silicone oils containing Si-OH or Si-H groups, all of which is dissolved in organic solvents. Also known from Polish Patent No. 100,633, a composition consisting of a polysiloxane resin, silicone oil containing Si-OH or Si-H groups and alkenyl (alkyl) -triacyloxysilane is used to make coatings on porous materials, especially on paper. The disadvantage of these compositions is the low reactivity which causes the need to heat them at elevated temperatures to obtain a hydrophobic effect or to get a varnish coat on metals, especially coatings with high adhesion to the substrate. In addition, the compositions described are not capable of forming chemical bonds with the materials to be coated, which causes the coatings to lose their adhesion and flaking during prolonged soaking.

148 704

The methods of obtaining polysiloxane compositions obtained above do not take into account the reactions occurring during the mixing of reagents, which in each case results in the formation of compositions with different properties.

The polysiloxane composition according to the invention, containing polysiloxane resins and organic solvents, is characterized in that it contains 10-80 parts by weight of solutions of polysiloxane resins containing 30-60% by weight of resin, 1-40 parts by weight of alkoxysilanes, 0.01-10 parts by weight of alkyl (alkenyl) chlorosilanes and 10-100 parts by weight of organic solvent.

It was found that elastic coatings are obtained using solutions of alkyl polysiloxane resins with R / Si = 1: 1.2, while hard coatings with high adhesion to metals and plastics are obtained using a mixture of solutions of alkyl polysiloxane resins with R / Si = 1: 1,2 with alkyl-aryl-polysiloxane resins with R / Si = 1.1: 1.5 in a weight ratio of 1: 0.1 to 1: 3. It has been found advantageous to use toluene or acetone as solvents.

The polysiloxane composition according to the invention has a high reactivity, due to which it cures at room temperature. The use of organic solvents to dilute the resulting polysiloxane compositions extends the life of the composition and allows the application of coatings of the required thickness.

At the same time, it was found that the method of mixing individual components of the composition is not indifferent, as the hydrolysis and condensation reactions of polysiloxanes that occur can form polymers with a higher structure.

To obtain a composition with the desired properties, 10-80 parts by weight of a solution of polysiloxane resins containing 30-60% by weight resin, which is an alkyl polysiloxane resin, are introduced into 10-100 parts by weight of an organic solvent and, after dissolving, optionally an alkyl-aryl-polysiloxane resin. After the gums are completely dissolved, 1-40 parts by weight of alkoxysilanes are added and the ingredients are mixed for 10-60 minutes. If the solution is cloudy, desiccants, preferably type 4A molecular sorbents or magnesium carbonate, are introduced. After obtaining a clear solution, 0.01-10 parts by weight of alkyl- (alkenyl) -chlorosilanes are added in portions with vigorous stirring for 10-30 minutes. The resulting composition is left for about 24 hours before use.

Example I. Composition: 20 parts by weight of a 50% solution of methylsilicone resin with R / Si = 1.0 to 1.2.2 parts by weight of a 50% solution of phenylsilicon resin with R / Si = 1.2 to 1.5 , 5 parts by weight of tetraethoxysilane, 0.3 part by weight of vinyl-trichlorosilane, 30 parts by weight of toluene.

This composition creates a coating on metals that cure at room temperature with high flexibility. A 10% solution of this composition in toluene used to hydrophobize concrete or wood makes these materials resistant to moisture penetration.

Example II Composition: 10 parts by weight of a 50% solution of methyl silicone resin with R / Si = 1.0 to 1.2, 5 parts by weight of a 50% solution of methyl phenylsilicone resin with R / Si = between 1.2 and 1.5, 5.3 parts by weight of tetraethoxysilane, 1.0 part by weight of methyl trichlorosilane, 100 parts by weight of acetone.

This composition creates coatings that cure at room temperature and are distinguished by high adhesion to both metals and silicone rubbers. This composition mixed with solutions of vinyl-butyrol creates durable, tight coatings on wood, concrete, etc.

Example III. A composition having the composition given in Example 1 is obtained as follows.

To 30 parts by weight of toluene are added 20 parts by weight of a 50% solution of methylsilicone resin with R / Si = 1.0 to 1.2 while stirring. After obtaining a homogeneous solution, 2 parts by weight of methyl-phenyl-silicone resin with R / Si = 1.2 to 1.5 are added and the whole is mixed until both components are completely dissolved. Then 5 parts by weight of tetraethoxysilane are added, the mixture is mixed for 40 minutes. In the case of turbidity of the solution, desiccants of the 4A type sorbents are added in an amount of 1% by weight relative to the solution, and after mixing for 60 minutes, the sorbents are separated. Dc of the dried solution is added with vigorous stirring 0.3 parts by weight of vinyl trichlorosilane. The whole composition is mixed

148 704 3 an additional 30 minutes, poured into glass containers and left for 24 hours before use.

Example IV The composition given in Example 2 is obtained as follows:

To 100 parts by weight of acetone are added by stirring 10 parts by weight of a 50% solution of methyl-silicone resin with R / Si = 1.0 to 1.2. After obtaining a homogeneous solution, 5 parts by weight of a 50% solution of methyl-phenyl-silicone resin with R / Si = 1.2 to 1.5 are added and mixed until both resins are completely dissolved.

Then 5.3 parts by weight of tetraethoxysilane are added and the solution is stirred for 15 minutes. If the solution is cloudy, drying agents such as magnesium carbonate are added in an amount of 1% relative to the solution, and after stirring for 2 hours, the precipitate falling to the bottom of the reactor is separated.

To the clear, dried solution, methyl trichlorosilane is added in an amount of 1 part by weight and stirring is continued for 10 minutes. After mixing, the solution is poured into sealed glass containers and left for 24 hours before use.