RU2552560C2 - Glue compound for veneer production and preparation of filler for said compound - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to woodworking and can be used for glued laminar materials (veneer, veneer boards, curved and flat work pieces). Production of filler comprises drying and mixing. Filler as hydrolytic lignin is processed with 4-10% solution of sodium thiosulphate (Na₂S₂O₃) at adsorbent-to-solution ratio makes 1:3. This mix is mixed for 10 minutes at 100°C for 4 hours. Proposed glue composition comprises phenol-formaldehyde resin, paraformaldehyde and filler, that is, hydrolytic lignin processed with sodium thiosulphate.

EFFECT: better ecological properties, higher mechanical characteristics.

2 cl, 3 tbl

Description

The invention relates to the woodworking industry and can be used in technological processes for the production of glued laminated materials (plywood, plywood boards, bent and flat glued workpieces).

A known method of producing a filler is hydrolytic lignin, which includes the following operations: preliminary grinding, drying of raw hydrolysis lignin, grinding dry hydrolysis lignin (Nikitin V.M., Obolenskaya A.V. “Shegolev V.P. Chemistry of wood and cellulose. M .: Forest industry, 1978.- 368 p.).

A known adhesive composition comprising phenol-formaldehyde resin of a resol type SFZh-3014 (V. Kondratyev and others. Water-resistant adhesives in woodworking. M: Forest industry, 1988, p. 51).

The disadvantages of the existing adhesive composition are the toxicity of adhesive compositions and plate materials made with their use, low adhesive strength.

An object of the invention is to obtain glued laminated materials with improved environmental properties and increased physical and mechanical properties.

The problem is solved in that in the method of producing a filler, including drying, grinding, it is new that the filler in the form of hydrolytic lignin is treated with a 4-10% solution of sodium thiosulfate (Na ₂ S ₂ O ₃ ) in relation to the mass of the adsorbent to the mass 1: 3 solution, stir the mixture for 10 minutes and dry at 100 ° C for 4 hours.

In the adhesive composition for the manufacture of glued laminated materials, including phenol-formaldehyde resin, paraformaldehyde, filler, according to the invention, the filler treated with sodium thiosulfate hydrolysis lignin in the following ratio, wt. %:

phenol formaldehyde resin 92.5-94.0 treated with sodium tisulfate (Na ₂ S ₂ O ₃ ) filler (hydrolysis lignin) 5.0-6.5 paraformaldehyde 1,0

To implement the technical solution, phenol-formaldehyde resin of any grades used in the production can be used (SFZh-3013, SFZh-309, SFZh-3014), which will make it possible to obtain glued wood materials with improved environmental properties and increased physical and mechanical properties.

Obtaining a modified filler (hydrolysis lignin), with good adsorption properties, was carried out as follows.

The studied factor contributing to an increase in the degree of formaldehyde concentration decrease was the acid treatment of adsorbents. Hydrolysis lignin was treated with a solution of sodium thiosulfate of various concentrations. The concentration of sodium thiosulfate solution varied in the range of 4-10%.

Example 1. In a ceramic cup is placed 20 g of hydrolysis lignin and poured 30 g of sodium thiosulfate 4% concentration. The mixture is thoroughly mixed until a homogeneous state. Then the obtained jelly-like mass is placed in an oven with natural air circulation and dried at a temperature of 100 ° C for 4 hours. After drying, the processed samples are ground in a mortar.

Example 2. Analogously to example 1, 20 g of hydrolysis lignin is placed in a ceramic cup and 30 g of sodium thiosulfate of 6% concentration are added.

Example 3. Analogously to example 1, 20 g of hydrolysis lignin is placed in a ceramic cup and 30 g of sodium thiosulfate of 8% concentration are added.

Example 4. Analogously to example 1, 20 g of hydrolysis lignin is placed in a ceramic cup and 30 g of sodium thiosulfate of 10% concentration are added.

The research results are given in table. one.

In order to select the optimal mass ratio of hydrolytic lignin (m_{hydraulic lign}) and sodium thiosulfate (m_{thiosulf.sodium}) experiments were conducted where the ratio m_{hydraulic lign}: m_{thiosulf.sodium} ranged from 1: 1 to 1: 5.

It was found that the greatest effect was obtained with respect to

m _hydr . _lign : m _thiosulf . _sodium = 1: 3.

The resulting mixture was stirred for 5-15 minutes. The most complete wetting of hydrolysis lignin with sodium thiosulfate was achieved by stirring the mixture for 10 minutes. The mixture was dried to a moisture content of 2-3% at a temperature of 100 ° C for 4 hours.

To verify the quality of the adhesive compositions obtained with the modified filler, the following adhesive recipes for the manufacture of plywood are prepared, are presented in table. 2.

For the manufacture of plywood, coniferous shelving veneer was used that meets the requirements of GOST 99-96.

Method 1. In the laboratory, tests were carried out on samples of plywood glued from sheets of pine veneer with an adhesive composition prepared according to the method described above. As a binder, phenol-formaldehyde resin of the SFZh-3013 brand was used in an amount of 92.5 wt. %

The veneer bonding modes are as follows:

glue consumption 120 g / m ² temperature of press plates 130 ° C pressing pressure 1.8 MPa pressure holding time 2 min per 1 mm of plywood thickness.

Method 2

The method of producing glued plywood was carried out according to method 1, while the binder used phenol-formaldehyde resin brand SFF-309 in an amount of 93 wt. %

Method 3

The method of producing glued plywood was carried out according to method 1, while the binder used phenol-formaldehyde resin brand SFF-3014 in an amount of 94 wt. %

Plywood glued with different adhesive recipes according to the above technological conditions was tested for strength when chipping along the adhesive layer and the content of free formaldehyde was determined. The test data are given in table. 3.

From table 3 it is seen that the index of tensile strength when chipping along the adhesive layer meets the requirements of GOST 3916.1-96.

The content of free formaldehyde was determined by non-destructive samples of plywood by the method (laboratory desiccation method). In plywood glued on adhesives according to examples 1-4, the content of free formaldehyde is lower than that of the prototype, because hydrolysis lignin treated with sodium thiosulfate has adsorption properties.

Claims (2)

1. A method of producing a filler, including drying and grinding, characterized in that the filler in the form of hydrolytic lignin is treated with a 4-10% solution of sodium thiosulfate (Na ₂ S ₂ O ₃ ) in relation to the mass of the adsorbent to the mass of the solution 1: 3, stir the mixture for 10 minutes and dried at a temperature of 100 ° C for 4 hours 2. The adhesive composition for the manufacture of glued laminated materials, including phenol-formaldehyde resin, paraformaldehyde, filler, according to the invention as a filler, it contains hydrolysis lignin according to claim 1 in the following ratio, wt. %:
phenol formaldehyde resin 92.5-94.0 specified filler treated with sodium thiosulfate (Na ₂ S ₂ 0 ₃ ) - hydrolysis lignin 5.0-6.5 paraformaldehyde 1,0