RU2286370C1 - Facing mastic - Google Patents

Abstract

FIELD: building materials.

SUBSTANCE: invention relates to compositions of mastics used for profiling facing of wood backings and for repair works as a spackling compound that can be used in building, furniture manufacturing and other fields. Mastic comprises polyvinyl acetate lacquer in acetone medium and polystyrene lacquer in toluene medium as a binding agent, a mixture of acetone with toluene in the ratio = 1:1 as a solvent, and finely divided powdered wood, brand 200 as a filling agent, and pare oil as an anti-adhesive agent. Invention provides reducing adhesion to metallic surfaces of using equipment and increasing adhesion to wood backings at optimal level of elasticity being without deterioration of decorative properties of ready articles.

EFFECT: improved and valuable properties of mastic.

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Description

The invention relates to the field of mastic compositions for profile cladding of wooden substrates, as well as for repair work as a putty that can be used in construction, furniture production and other fields.

Known adhesive mastic based on a filled polyvinyl acetate emulsion modified with bottoms of dimethyl terephthalate production, styrene butadiene latex with surfactant additives / 1 /.

The disadvantage of this composition is the high adhesion to the metal surfaces of the parts of the manufacturing and processing equipment, due to the adhesive ability of the rubber, and the corrosion activity of a water-based binder.

Also known is an adhesive mastic based on nitrocellulose modified with nitrile butadiene rubber with the addition of dibutyl phthalate, trichloroethyl phosphate, zinc oxide and castor oil / 2 /.

The disadvantage of this composition are also increased adhesion to metal surfaces and fire hazard when using nitrocellulose.

The closest in technical essence and the achieved result to the proposed one is facing mastic, including joiner's glue, liquid galert glue, filled with powdered chalk with additives of rosin, machine oil and drying oil / 3 /.

A disadvantage of the known material is the high density of the material, poor elasticity due to the increased level of internal stresses leading to deterioration of decorativeness, cracking of products, increased adhesion to metal surfaces of technological equipment and insufficient adhesion to wood substrates, requiring an additional sublayer for reliable adhesion of the cladding to the wood substrate.

The objective of the invention is the reduction of adhesion to the metal surfaces of the equipment used while increasing adhesion to wooden substrates, with an optimal level of elasticity that does not impair the decorativeness of finished products.

The problem is solved in that the facing mastic includes a binder, solvent, filler and release agent, while it contains a polyvinyl acetate varnish on acetone and a polystyrene varnish on toluene as a binder, as a solvent: a mixture of acetone with tululine in a ratio of 1: 1, as filler - finely divided wood flour, and rapeseed oil as a release agent, in the following ratio of components, wt.%:

polyvinyl acetate varnish on acetone 30-35 polystyrene polish on toluene 10-15 rapeseed oil 6-8 fine wood flour, grade 200 30-42 solvent - acetone: toluene = 1: 1 rest

Varnishes are used at a 40% concentration due to the optimal ratio between the rheological characteristics and the solvent consumption. The invention and the hypothetical mechanism of action of the components is as follows.

Facing mastic should have selective adhesion, i.e. in the uncured state, adhesion to the metal surfaces of technological equipment and the operator’s hands should be completely absent, at the same time, when used (applied to the substrate) and in the cured state, the mastic should form a layer strongly bonded to the surface. Lack of adhesion to metal surfaces and operator's hands is achieved by using rapeseed oil as an anti-adhesive, which is added in the optimal amount. A thin film of oil covering metal and other surfaces prevents the interaction of the active groups of the polymer matrix, while at the same time it does not reduce the adhesion of the cured layer to the substrate.

To ensure cohesion (intrinsic strength, elasticity) of the material, a binder is used, which is obtained by reacting a solution of one thermoplastic polymer in an organic solvent with another thermoplastic polymer in another solvent, and the solvent of one polymer serves as a precipitant for the other. This allows, when mixed as a result of polymer interaction, to obtain a compound with a higher molecular weight and to precipitate a part of a high molecular weight substance - a binder on the filler, thereby ensuring greater elasticity of the material and strength of the interparticle layer, i.e. cohesion. The precipitation in polymer solutions is also facilitated by the use of special precipitants - vegetable oils - at various technological stages (preparation of the adhesive base or after mixing all the components). Effective modification and precipitation occurs by mixing concentrated solutions of the proposed polymers. However, such a process, leading to an increase in the elasticity and cohesion of the material, can significantly worsen its decorative and technological properties. In this regard, the composition of the binder was optimized according to the degree of polymerization, concentration, polymer ratio and solvent ratio.

The introduction of wood flour reduces the specific gravity of the material, and its high dispersion contributes to the shaping and decorative coating. A higher dispersion degrades the processability (the occurrence of dusting), and a lower dispersion degrades decorativeness. The use of wood flour in combination with a binder and rapeseed oil provides a strong adhesion of the facing layer to the substrate in the cured state, which eliminates the use of an additional adhesive sublayer and reduces the number of technological operations.

Facing mastic is prepared as follows.

Polyvinyl acetate varnish on acetone and polystyrene varnish on toluene are successively introduced into the filler. Varnishes are used at 40% concentration. The mixture was stirred for 10 minutes, rapeseed oil was added and mixed again for 10 minutes. Then add the solvent (a mixture of acetone and toluene) and mix again for 5 minutes

The specific compositions of the mastics are shown in table 1.

Table 1 Components Amount, wt.% one 2 3 Polyvinyl acetate varnish on acetone TU 6-10-1081-80 thirty 33 35 Lacquer polystyrene on TU 6-05-1604-82 toluene 10 13 fifteen Rapeseed oil GOST 1129-93 6 7 8 Wood flour, brand 200 GOST 16381-87, brand 200 thirty 35 42 Solvents - Acetone: Toluene = 1: 1 rest rest rest

Characteristics of mastics of different composition in comparison with the known composition are shown in table 2.

table 2 Characteristics Compositions Proposed by Example Famous one 2 3 one 2 3 four 5 Density, kg / m ³ 2200 2350 2300 2600 Adhesion to the metal surfaces of uncured mastic processing equipment - - - + The adhesion to the wood substrate of the cured mastic, not less than MPa 1.9 2.2 2,4 0.9 Drying time, hour 24 24 24 48 Decorative (estimated by a five-point system) 5 5 5 four The surface area of the cured sample, covered with cracks,% (estimated visually) - - - 2 7 days exposure - - - 10 30 days exposure - - - twenty 500 days exposure

The adhesive ability of the mastic was determined according to GOST 24064-80. The density of the material was determined according to GOST 15139-69. The surface area of the cured sample, covered with cracks, in% was evaluated visually.

As can be seen from the tables, the proposed mastic has minimal adhesion to the metal surface of technological equipment, and to wood substrates is quite large, the use of an additional adhesive sublayer is not required. The drying time of the decorative coating due to the optimal selection of organic solvents, which binds to various evaporation temperatures, reduces internal stresses, eliminating cracking and providing high decorative effect. The use of organic solvents in the composition of the mastic, subject to the rules for working with volatile substances, is not dangerous.

Information sources

1. USSR author's certificate No. 808508, IPC C 09 J 3/14, 1981.

Published in the bulletin "Discoveries, inventions, industrial designs, trademarks" No. 8, 1981.

2. Russian patent No. 2083625, IPC C 09 J 101/18, 1997. Published in the bulletin "Inventions", No. 19, 1997.

3. Zamokin VV, Kalugin A.E. Baguette production at woodworking enterprises. M., TSNIITI, 1961 (prototype).

Claims (1)

Facing mastic, including a binder, solvent, filler and release agent, characterized in that it contains a polyvinyl acetate varnish on acetone and a polystyrene varnish on toluene as a binder, a 1: 1 mixture of acetone and toluene as a solvent, and finely dispersed as a filler wood flour grade 200, as a release agent - rapeseed oil in the following ratio of components, wt.%: Acetone polyvinyl acetate varnish 30-55 Polystyrene polish on toluene 10-15 Rapeseed oil 6-8 Fine wood flour, grade 200 30-42 Solvent - Acetone: Toluene = 1: 1 Rest