SU939298A1 - Method of producing fibreboards - Google Patents

Description

one

The invention relates to the production of building materials, namely the production of fibreboard.

A known method of manufacturing fiberboard, including grinding chips for fiber, pouring pulp, partial dehydration of the carpet, followed by flat KIM pressing at 190-21 (f C and specific pressure 5.0-5.5 MPa p.

This method produces slabs with a surface on which large wood fibers and bark particles are contrasted.

The closest to the proposed technical essence is a method of manufacturing fibreboard plates by applying to the wet fibre carpet of a finishing composition based on an aqueous solution of lignosulfonate - sulfite-alcohol bards concentrate followed by

by pressing at 180-195 ° С and specific pressure 5.0-5.5, MPa 2.

The disadvantages of this method are the loss of lignosulphonate with wastewater during hot pressing of wood-fiber carpet, foaming during preparation and application of the composition, due to the alkaline character of stillage, the gray-brown color of the front surface of the plates, the formation of spots on the mesh side of the plates due to uneven adsorption of lignosulfonate on carpet fibers.

The purpose of the invention is to increase the hiding power of the coating and bending strength.

The goal is achieved by the fact that in the method of manufacturing fibreboard by applying a finishing composition based on an aqueous solution of lignosulfonate on a wet fibrous carpet and then pressing a specific pressure at 180ISS CW of 5.05–5 MPa, the composition comprising solution of ligiosulfonate (in terms of 50% concentration) 80-90 Liquid glass (in terms of 50% concentration) 0.8-2.0 Dye 0.15-3.3 Wood flour 1.5- 3.0 .S ° A9 Else As lignosulfonate form a dense liquor spol neytralnosulfi Nogo production on the ammonium osiovanii comprising wt.% lignosulfonate and complex wt.% hemicellulose. Mineral pigments from the group of jelly, zooxide pigments, pickles of Tona forces, and their mixtures are used as dyes. I The method is carried out as follows. Solid fibreboard of the wet method is obtained according to the traditional technology, including spreading on a defibrator, obtaining fiber with grinding 19 - defibrator seconds in the refinator feeding the fiber into the mass pool, where they get a mass with a fiber concentration of 1-1.5 mas. sizing the mass with hydrophobic additives, introducing reinforcing additives (albumin, resin, etc), draining the mass in the form of a carpet, its partial dehydration, and hot pressing. The finishing composition is prepared as follows. Lye, liquid glass are poured into the mixer with a paddle mixer (60-80 rpm), the dye and wood flour are poured, water is introduced and stirred for 2-3 hours at 18-23 ° C, after which the finished composition is pumped through the supply tank to the nozzle, which sprays the composition onto a wood-fiber carpet (in the area after cross cutting the carpet). The specific consumption of the composition is 200-300 g / m. Table 1 presents examples of finishing compositions used in the proposed method. 1t a b-l and c a 1

Dense lye of neutral sulphite production on ammonium base (in terms of concentration)

Liquid glass (in terms of

 concentration (module

2.6)

Dye - iron minium

either redox or ocher

and / or pickle Tonaxil

Wood flour (size .140 and 250 microns)

Water

The compositions in examples 1-3 have a pH of 5 to 6-5 | In the content of non-volatile in them ii3, masd.

Wood-fiber carpets with the following characteristic are used: the pedigree composition of needles and hardwood (rocks, respectively, 50-65 and

83.0

1.0

2.7

1.8 Else

bark content is 8-12, rot content is 0.9-1.1%, grinding weight is 18-20 DS, carpet moisture 70.-71%, carpet thickness 18-19 mm, pH of the carpet 4.1-C, 3. Hot pressing is carried out in accordance with the regime adopted in enterprises manufacturing hard fiberboard of the wet production method. The thermoaccount of the plates is completed with the prototype finish at 150-160 ° C for 4.5 hours, and the proposed method is performed at 10O-11 for 3 hours. The compositions apply hydrate 320-330.

29-32 22-2i

19-21 18-20

.rospray through a nozzle with a specific flow rate, in the known method - 350-00, the proposed 200-300., Characteristics of the finished plates with S are listed in Table. 2

table 2

i 60-510 it30- 60

U-18

20-21 16-18 12-13

Claims (2)

Claim 1. A method of manufacturing wood- ₄₅ fibrous boards by applying a finishing composition based on an aqueous solution of lignosulfonate to a wet wood-fiber carpet and then pressing at 180-195? C and _m specific pressure of 5.0-5.5 MPa, characterized in that, in order to increase the spreading rate of the coating and bending strength, a composition, _J5 comprising, wt.%: _Is used as a finishing composition: An aqueous solution of lignosulfonate (in terms of 50% concentration) Liquid glass (in terms of 50% concentration) Dye Wood flour Water 2. The method according to π. 1, dubious 80-90 ’0.8-2.0 0.15-3.3 1.5-3.0 The rest. about l and - that as a lignosulfonate, a dense neutral-sulfate - liquor is used, produced on an ammonium base, containing 40-45 wt.% of the lignosulfonate complex and 40-45 wt.% of hemicellulose.