SU1703667A1 - Compound for wood-fiber and chip boards - Google Patents

Abstract

The invention relates to woodworking, in particular to the preparation of press compositions for the production of fibreboard and particle board. The invention makes it possible to improve the vibration-absorbing properties of the plates by using a composition containing, in wt%: polyvinyl acetate dispersion 13.0 - 20.0; carbamide formaldehyde resin 4.0-6.0; dibutyl phthalate 7.5 - 11.0; OP-7.0 0.9-1.32; wood fiber else. 2 tab.

Description

The invention relates to the field of woodworking, in particular to the preparation of press compositions for the production of fibreboard and particleboard.

The purpose of the invention is to increase the vibration-absorbing properties of the plates.

Example 1: The components of the composition are metered into the stirred reactor at the following ratio, wt%: Polyvinyl acetate dispersion 13 Urea-formaldehyde resin 4 Dibutyl phthalate 7.5 OP-7 0.9 add water until a 40% solution is obtained concentrations include agitator and mix contents. After mixing, the working solution is poured into the supply tank. Then a portion of wood fiber is loaded into the drum mixer and through a pneumatic nozzle

enter the binder. The ratio between the binder components and wood fiber is as follows, wt.%:

Polyvinyl acetate dispersion 13.0 Urea-formaldehyde resin 4.0 Dibutyl phthalate 7.5 OP-7 0.9 Wood fiber Remaining Wood fiber treated with a combined binder is dried in a gas dryer at a temperature of 120 ± 1.0 ° C to a moisture content of 14%. From the dried press mass, carpets of 550 x 550 x 100 mm in size are manually formed in the frame. they are pressed in a cold press to give them sufficient stability, and then plates are pressed from a VP-9024 M press from these carpets. Pressing is performed using remote (restrictive) straps at a temperature of 180 ° C. maximum pressing pressure 2.5

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MPa and duration 0.5 min / mm. After cooling, pressed plates are cut into separate samples for testing in order to evaluate the physicomechanical and acoustic properties of the proposed plates in comparison with the known ones. The loss factor, the dynamic elastic modulus and the loss modulus are determined by the known method of forced resonant bending vibrations.

Table 1 shows examples of the implementation of the proposed technical solution, and Table. 2 shows the comparative results of tests of known and proposed plates.

The physicomechanical and acoustic characteristics of the material based on wood (wood boards) for the preparation of high-quality acoustic system (AC) enclosures should have the following values: density 600-700 kg / m3; thickness is 8-12 mm; attenuation coefficient (loss) of at least 0.1; static bending strength 13 - 19 MPa; dynamic modulus of elasticity (Young's modulus) not less than 1340 n / m2 (MPa).

From Tables 1 and 2, it follows that for the manufacture of high-quality speaker enclosures, plates manufactured according to the proposed formulation given in Table 1 are suitable (examples 1-3).

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION A wood board composition comprising a wood filler, a carbamide-formaldehyde resin and a polyvinyl acetate dispersion, characterized in that, in order to increase the vibration-absorbing properties of the plates, it contains wood fiber with a grinding degree of 350 to 400 units. PV and additionally dibutyl phthalate and surfactant OP-7 in the following ratio, wt.%: Polyvinyl acetate dispersion 13, 0-20.0 Kerbamide-formaldehyde resin 4,0 - 6,0 Dibutyl phthalate 7,5 - 11,0 Surfactant OP-7 9,1-1,32 Wood fiber with a degree of grinding 350-400 units. PV Else Table 1 table 2