SU1416501A1 - Plywood coating composition - Google Patents

Abstract

The invention relates to the field of construction and can be used in the manufacture of plywood for formwork in the manufacture of reinforced concrete and wood concrete structures. The invention makes it possible to reduce the roughness and increase the resistance of the coating to cyclic effects due to the use of recycled polyamide with a melting point of 202-225 ° C, obtained from cord waste or fiber waste, in the composition, wt.hour: water-soluble phenol formaldehyde resin 100; glycerin 5-10, secondary s polyamide 5-10. 3 tab. c

Description

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The invention relates to the construction and can be used in the manufacture of plywood for formwork in the manufacture of reinforced concrete and arbolite structures.

The aim of the invention is to reduce the roughness and increase the durability of the coating during operation.

The package is collected from veneer thickness

1.5 mm, water-soluble phenol-formaldehyde resin (SFZH-ZOP) is applied on even sheets on both sides. At the same time, a composition consisting of a water-soluble phenol-formaldehyde resin of the SPF-ZOP brand, secondary powdered polyamide (G1A) and glycerin o

The consumption of water-soluble phenol-formaldehyde resin and coating mixture is 140 g / m.

After assembly, the bag is covered with an anti-adhesion polyethylene terephthalate film and a cold underpressure is performed under the following mode: 1MPa cold prepressing pressure, temperature of press plates tоо „18-22 С, time in cold prepressing is 00 s,

Hot bonding is carried out in one bag in the middle of the press. 4 mm plywood thickness under the mode: hot-pressing pressure 2.0 MPa, hot-pressing time

 6 mountains 200 s, pressure relieving time C 60 s, temperature of hot plates of the press trop - 145 - 2 C.

PA is used as a secondary PA, which is obtained from PA fiber wastes or from a cord of used tires.

A secondary polyamide powder is obtained by re-precipitating from a solvent (ethylene glycol). The technological process of separating secondary PA from cord waste or fiber waste 63.8-81 consists of the following operations: dissolving from PA strokes at 165-170 ° C for 40-45 minutes, filtering the solution to separate non-polyamide components of pulp, planting powdered polyamide when cooled. In this case, the cooling is carried out gradually, smoothly at a speed of no more than 5 degrees / min.

Secondary PA is a fine powder with a particle size of 1-30 microns. Polyamide powder obtained from fiber waste for physico-mechanical properties is not

inferior to primary PA, Polyamide powder isolated from waste polyamide cord, has lower rates (see Table 1).

Table 2 shows the formulation of the composition according to the invention,

Table 3 presents data on physicomechanical properties.

Claims (1)

The indicator of the resistance of the coating to cyclic effects is lexical: it indirectly characterizes the elasticity of the coating and its water-permeability, resistance to temperature differences. Each test cycle consists of a sample containing samples in an alkaline solution of cement milk for 6 hours and drying them at 80 ° C for 2 hours. The resistance of the coating to cyclic testing is determined by the number of cycles after which the coating begins to crack. A plywood coating composition that includes a water-soluble polyethylene phenol-formaldehyde resin, glycerin, and a filler, which, in order to reduce roughness and increase the cyclic resistance of the coating, contains a secondary polyamide with a melting point of 202- 225 0, obtained from waste cord or fiber waste, in the following ratio of components на noso: Water soluble Phenol-formaldehyde resin Secondary poly100 Characteristic viscosity, ml / t 25.5 Molecular mass 2850 113 27450 Water soluble phenol formaldehyde resin Secondary PA Glycerin Coating hardness, MPa Wetting angle, hail Adhesion Carbolite, MPa Roughness tests, in the denominator - after 5 test cycles. The value is for 3 test cycles, since already with 3 test cycles on the coating significant cracks were formed. - 1416501 table 2 100 5 5 100 7.5 7.5 Table 3 180 165 171 77 68 73 0.001 0.0012 0.004