A method of manufacturing a molded lignocellulosic material

 

(57) Abstract:

Usage: in the pulp and paper industry for preparation of pressed lignocellulosic materials. The inventive method comprises grinding the wet wood filler, drying, mixing with the technical lignosulphonate, the formation of the carpet and its pressing. Technical lignosulphonate pre-treated with mineral acid to a pH of 0.3 - 2.0. Source lignosulfonate take the number 18 to 65 wt.% abs. dry. wood filler. The filler is subjected to drying after mixing it with processed technical lignosulphonate to a moisture content of a mixture of 3 - 13% immediately before the formation of the Mat. The pressing is performed at a pressure of 3 to 8 MPa for 1 to 2 min/mm thickness of the carpet. As wood filler can be wood chips, sawdust, or their mixture. 1 C.p. f-crystals, 1 table.

The invention relates to the pulp and paper industry, and in particular to methods of obtaining pressed lignocellulosic materials, mainly wood chipboard, for construction and decoration purposes.

A method of obtaining chipboard (particleboard), where as a binder is with the subsequent introduction of ammonium persulfate [1] in the following ratio of components, wt.%:

Urea-formaldehyde resin 59-94 Lignosulfonate at pH 6-7 5-39 ammonium Persulfate 1-2

There is also known a method of manufacturing particleboard, where before resinification of wood particles with a solution of urea-formaldehyde resin are applied on them, the mixture of aqueous solutions of ammonium chloride and lignosulfonate [2].

In both ways as the main binder used urea-formaldehyde resin, which is toxic and expensive product.

Closest to the claimed technical essence and the achieved result is a method of manufacturing particleboard, including chopping wood processing wood chips lignosulphonates and thermosetting resin, the formation of the Mat and hot pressing [3].

In this way the wood chips are treated first as a lignosulfonate, followed by her 20-50 minute exposure, and then treated with thermosetting resins.

The disadvantage of this method is the low resistance of the obtained plates, their toxicity due to the use of thermosetting resins, as well as the relatively high cost of these resins.

New technical result of the proposed method is that it p the spine.

This is achieved by the fact that the technical lignosulphonate pre-treated with mineral acid to a pH of 0.3-2.0, with lignosulfonate take the number 18 to 65 wt.% abs. dry. wood filler, and the filler after it has been mixed with the treated lignosulfonate being dried to a moisture content of the mixture 3-13% immediately before the formation of the Mat, and pressing is performed at a pressure of 4-8 MPa within 1-2 min/mm thickness plate. If you use wood filler wood chips, sawdust or a mixture thereof.

The author found that carrying out drying after mixing of lignosulfonate with a wood filler facilitates the impregnation of wood particles lignosulphonates, while for the reaction of copolymerization need to increase the exposure time by pressing the up to 1-2 min/mm thickness plate. When this is achieved the result takes place only during preview processing of lignosulfonate acid, i.e., the present invention meets the requirement of inventive step.

Decreasing the moisture content of the mixture below 3% having difficulty in the formation of the Mat, with the increase more than 13% there is a strong steam and gaseous selection PSAT sulphite lye on calcium-sodium base concentration of 40%, with constant stirring is added sulfuric acid to a pH of 1.0. Then acidified thus lignosulfonate is mixed with wood filler - sawdust in the amount of 50 wt.% abs, dry. filler, and the resulting mixture is dried to a moisture content of 10% . Then spend the formation of the Mat and hot pressing at specific pressure of 5 MPa, a temperature of 150aboutC for 15 minutes

P R I m e R s 2 and 3.

The sequence of implementation techniques analogous to example 1, but vary the values of the parameters pH, the ratio of lignosulfonate and wood filler, moisture content of the mixture before pressing, pressure and duration of pressing within the above ranges, as well as in example 2, as lignosulfonate used sodium sulphite lye Foundation.

P R I m e R s 4-11.

The method is carried out similarly to examples 1-3, but with parameter values outside the range shown in the formula of the invention (see table).

Conditions for obtaining the plates, and their basic parameters for the plate thickness of 10 mm is shown in the table.

As can be seen from the data given in the table, the proposed method compared with the method of the prototype provides the result to the improvement of the properties of the material. The proposed method can also reduce the toxicity of the plates and their cost due to elimination of toxic and expensive thermosetting resins.

Thus, the invention provides for the achievement of the technical result and feasible on the existing equipment with the use of industrially produced chemicals and raw materials and production waste, and therefore meets the requirement of industrial applicability.

1. A method of MANUFACTURING a MOLDED LIGNOCELLULOSIC MATERIAL comprising a grinding wet wood filler, drying, mixing with the technical lignosulphonate, the formation of the Mat and pressing, characterized in that the technical lignosulphonate pre-treated with mineral acid to a pH of 0.3 - 2.0, the original lignosulfonate take in the number of 18 - to 65% of the mass of absolutely dry wood filler, the filler is subjected to drying after mixing it with processed technical lignosulphonate to a moisture content of a mixture of 3 - 13% immediately before the formation of the Mat, and pressing is performed at a pressure of 3 to 8 MPa for 1 mm thickness of the carpet within 1 to 2 minutes

2. The method according to p. 1, characterized in that the quality of wood

 

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