RU2493001C1 - Pulp for making wood particle boards - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to production of construction materials and may be used for making particle boards for facing and heat-insulation in construction, ship building, production of furniture and consumer goods. Pulp comprises minced wood chips and biobinders based on modified brewer's yeast wastes at the following ratio of components in wt %: wood chips - 64-70, biobinder based on modified brewer's yeast wastes - 30-36.

EFFECT: higher strength, lower toxicity and costs.

2 tbl

Description

The invention relates to the production of building materials and is intended for the manufacture of chipboards, which are used as facing, decorative, heat-insulating and structural material in civil, industrial, agricultural construction, shipbuilding, in the manufacture of furniture and consumer goods, in the manufacture of furniture and consumer goods consumption.

Known wood press pulp, including crushed wood, fibrous filler and phenol-formaldehyde resin [SU 331932, B27K 3/50, publ. 01/01/1972].

Plates made from such a material have increased impact strength, fire resistance and resistance to ammonia medium. Products from them do not require additional decorative processing. Such materials have a lower cost, due to the use of cheaper filler and lower binder consumption. However, such materials have increased toxicity, in addition, when preparing them, high energy costs, it is necessary to use harsh process conditions. The toxicity of particle boards is due to the release of formaldehyde gas harmful to human health from the boards after their manufacture, the concentration in the air of which is 10-20 times higher than the maximum permissible concentration (MPC) even after 3-6 months of exposure of the boards to the finished goods warehouse. Isolation of formaldehyde from boards is associated with the use of urea-formaldehyde or phenol-formaldehyde resins in the production of particle boards as a binder, which contain free formaldehyde.

The closest technical solution is a press mass for the manufacture of chipboards, including crushed wood particles, and as a binder use bone glue, previously dissolved in water to an adhesive content of 21-25% by weight [RU 2037505. C08L 97/02, B27N 3 / 04, C08L 97/02, publ. 06/19/1995].

However, taking into account existing prices for bone glue, its use as a binder increases the cost of chipboards. In addition, plates made using bone glue have a high density, which creates additional difficulties when processing products from such material (cutting, calibration, cutting in place, etc.), and in terms of bending strength they only slightly exceed those according to GOST.

The technical result consists in increasing strength, reducing toxicity and cost of finished products made from the claimed composition of the press mass.

The technical result is achieved by the fact that the press mass for the manufacture of wood-based panels contains ground wood chips and a biocontainer based on modified yeast waste from beer production, in the following ratio of components, wt.%:

Wood shavings - 64-70 Modified biocontainer beer production yeast - 30-36.

In the production of beer, solid waste is yeast cells (0.25-0.40 kg per 1 liter of beer), malt and hop grains, protein precipitate from the separator. Residual brewer's yeast is a dense mass with a specific yeast taste with a slight hop bitterness and a smell characteristic of fresh yeast. The mass fraction of solids in residual brewer's yeast is up to 15% wt.%. Yeast contains 24-30% solids, which are 90-95% composed of organic substances. Proteins and other nitrogen-containing substances in yeast contain 54-56%, carbohydrates - 24-40%, fats - 2-5%. The most famous yeast proteins are zymocasein (phosphoglobulin) and cerewizine. First, the residual brewer's yeast is treated with a 5% sodium hydroxide solution in a ratio of 1: 0.8 for 30 minutes and centrifuged for 15 minutes to obtain a modified precipitate of brewer's yeast. In the preparation of the biocomponent, the components were taken in the following proportions, masses,%: residual brewer's yeast treated with a 5% sodium hydroxide solution — 95.5, glycerol — 4.0, boric acid — 0.5. These components are mixed continuously for 10-20 minutes (RU 2404222, publ. 20.11.2010).

The method is as follows. Shredded wood shavings or sawdust are mixed with a biocontainer based on modified brewer's yeast waste (compositions are listed in Table 1) and dried to a moisture content of 7-8%, form a carpet by cold pressing and hot pressing under the following conditions: temperature 150 ° C, pressure and 3.5-4 MPa per millimeter of thickness, the duration of pressing is 0.5 minutes per millimeter of thickness. After heating and holding at a given temperature, the formed product is cooled to a temperature of 50-60 ° C. Plate material of any sizes and various configurations can be made from the proposed material. Table 2 shows the indicators of physico-mechanical properties of the plates obtained from the proposed composition, made as an example with a thickness of 10 mm

Plates made from the proposed composition of the press mass with a biocontainer based on modified yeast from beer production are not inferior in their properties to the known plate materials. In addition, the formaldehyde content per 100 g of a completely dry plate is reduced to 2 mg, which makes it possible to classify the plate material from the proposed press mass as toxicity class E ₁ (according to GOST 10632-2007). Based on the proposed composition of the press mass, plates are obtained without the addition of special reinforcing additives of organic resins. The exclusion of binders based on organic resins can reduce the emission of formaldehyde from finished products, as well as reduce their cost.

Table 1 The composition of the press mass Option 1 Option 2 Option 3 Wood shavings, wt.% 70 67 64 Binding agent based on modified yeast from beer production, wt.% thirty 33 36

table 2 Indicators Chipboard GOST 10632-2007 (for a thickness of 7-13 mm) A solution of bone glue 20% concentration of 20% by weight of wood raw materials Press-mass with biocontainer based on modified yeast from beer production Option 1 Option 2 Option 3 Strength in static bending, MPa 12.5-14.0 15.0 18.2 19.0 21.7 Tensile strength perpendicular to the plate face, MPa Not less than 0.40 0.30 1.00 1.10 1.20 Density, kg / m3 550-820 1000 810 840 830 Formaldehyde content, mg / 100 g dry plate (class E1) Up to 8 eleven 2 2 2

Claims (1)

A press material for the manufacture of chipboards, including crushed wood chips and a binder, characterized in that the binder contains a biocontainer based on modified yeast from beer production in the following ratio, wt.%:
Wood shavings 64-70 Modified biocontainer beer production yeast 30-36