SU1257079A1 - Composition for wood particle boards - Google Patents

Description

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The invention relates to the woodworking industry, namely to the production of chipboard.

The aim of the invention is to improve the physicomechanical properties of the plates.

The production of chipboard is carried out according to the following technology.

Wood chips with a moisture content of 3% are treated with a binder. The mass is stirred for 5-7 minutes, after which it is pressed in a hot press at 16015 С, specific pressure 2.0-2.5 MPa. Time voderki 0.6-0.7 min / mm, plate thickness 20 mm.

The binder is obtained by mixing 59-60% aqueous solutions of a urea-formaldehyde resin with a hardener.

257079

and the condensation product of urea and polyvinyl alcohol.

The product is obtained by the condensation of carbamide (90 wt. Parts) with high molecular weight polyvinyl alcohol.

(44 parts by weight) in the presence of glycerol (1.8 parts by hours). Glycerin performs the role of a catalyst. Condensation is carried out at 175-185 ° C for 2.5-3.5 hours. O The resulting resinous product has an OT-4 viscosity of 11-13.5 s, the molecular weight determined by the viscometric method is 1130-2690

completely soluble in water, acetone. 15

The formulations of the compositions according to the invention are given in table. 1. The test results of the composition according to the invention in comparison with the known and 20 controls are in table. 2

Table 1 Formulation Compositions

6.5 10.0 13.5

0.5 0.75 1.0

1.3 4.4 7.5

91.7 84.85 78

57079

and the condensation product of urea and polyvinyl alcohol.

The product is obtained by the condensation of carbamide (90 wt. Parts) with high molecular weight polyvinyl alcohol.

(44 parts by weight) in the presence of glycerol (1.8 parts by hours). Glycerin performs the role of a catalyst. Condensation is carried out at 175-185 ° C for 2.5-3.5 hours. O The resulting resinous product has an OT-4 viscosity of 11-13.5 s, the molecular weight determined by the viscometric method is 1130-2690,

completely soluble in water, acetone. 15

10.0 10.0 0.75 0.75

4.4

4.4 84.85 84.85

Chipboard properties (thickness 20 mm, density 850 kg / m)

Strength at a static bend, MPa 28,5

29.0 27.5 26.5 28.3 20.5 20.0

5.9 6.0 5.9 5.2 6.0 3.5

9.2 9.0 9.3 10.1 9.3

3.0 2.9 3.3 3.2 19.2

0.01 0.009 0.0095 Additive - a mixture of urea and polyvinyl alcohol.

.Editor, Sligan

Compiled by G. Stepanova

Tehred L. Serdyukova Proofreader M. Samborska

Order 4880/19

Circulation 470

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d, 4/5

Production and printing company, Uzhgorod, st. Project, 4

table 2

3.9

15.0

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Claims (1)

COMPOSITION FOR WOODBACKBOARDS, including urea-formaldehyde resin, an additive based on polyvinyl alcohol, a hardener and wood chips, characterized in that, in order to improve the physicomechanical properties of the plates, it contains the condensation product of polyvinyl alcohol and urea in the presence glycerol at a mass ratio of reagents 44: 90: 1.8, respectively, with a viscosity of 11-13.5 with a molecular weight of 1130-2690, and ammonium chloride as the hardener, with the following ratio of ponents, wt.%: Carb amide formaldehyde resin Polyvinyl condensation product 6.5-13.5 alcohol and urea 1.3-7.5. Ammonium chloride 0.5-1.0 Wood shavings Rest SU,, 1257079; and a condensation product of urea and polyvinyl alcohol. The product is obtained by condensation of urea (90 parts by weight) with high molecular weight polyvinyl alcohol (44 parts by weight) in the presence of glycerol (1.8 parts by weight). Glycerin acts as a catalyst. Condensation is carried out at 175-185 ° C for 2.5-3.5 hours ¹⁰ The obtained gummy product has a viscosity according to VZ-4 of 11-13.5 s, the molecular weight, determined by the viscometric method 1130-2690, is completely soluble in water, acetone. fifteen ' The formulation of the compositions according to the invention are given in table. 1. The test results of the composition according to the invention in comparison with the known and 20 control in table. 2. Table 1 Songs