RU2423397C2 - Moulding composition for moulding finishing slabs - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: moulding composition relates to agriculture, particularly to processing flax production wastes and compositions for producing finishing slabs. The moulding composition contains pile of flax, urea-formaldehyde resin KF-NU, polyvinylacetate dispersion, hardener - ammonium chloride, with given ratio of components, wherein the pile of flax contains a crushed flax in ratio of (1-3):(9-7).

EFFECT: use of the composition enables to obtain low-toxicity finishing slabs with high water resistance.

2 cl, 2 tbl, 7 ex

Description

The invention relates to agriculture, in particular to the processing of flax production waste, and relates to compositions for producing finishing boards. Of great importance to industry is the problem of recycling secondary material resources. Flax production is characterized by its multi-purpose use. The processing of bast fiber raw materials is accompanied by a large amount of waste, the fiber in the stem of the bast fiber stalk plants is about 15% of the mass, the remaining mass is waste in the form of a short indirect fiber of 20-30% and a fire of 50-60%, consisting of cellulose 40-50%, hemicellulose 15-20%, lignin 29-25%. Flax bonfire is used as fuel in the form of briquettes, to which peat crumbs are added or burned in the furnaces of flax mill boiler houses. Currently, flax bonfire is used in large quantities in heat-insulating, decorative and finishing boards.

Ecologically clean decorative decorative boards are known that are formed from a mixture containing the initial fire and the fire, which is previously subjected to grinding, mixed with water until a suspension is obtained.

(see Patent RU No. 2081098, С04В 18/24, 08/10/1997)

Known press composition for the manufacture of plates containing a flax bonfire treated with a hydrolyzing agent - sulfuric or phosphoric acid and a modifying agent selected from the group: iron salt, zinc salt, copper salt.

(see Patent RU No. 2202574, D27N 3/04, 04/20/2003)

A disadvantage of the known compositions is the unsatisfactory performance properties of the resulting boards, which have low water resistance.

Known raw mix for the manufacture of building boards, containing flaxseed fire, water glass, sodium carbonate, epoxy Dianova resin.

(see Patent RU No. 17979677, C 04 B 28/26, 12/07/92)

However, slabs formed from a known raw material mixture emit harmful volatile substances, and therefore they must be subjected to additional decoration.

The closest analogue of the claimed press composition for forming decoration boards is a press mass containing a flax bonfire, urea-formaldehyde resin and hardener.

(see. Copyright certificate No. 859191, 1 В27К 9/00, 08/30/81)

The disadvantage of the press mass is the low water resistance of the finished plates, and also these plates are toxic due to the negative effect of the resin on the environment.

The objective of the development is to increase the efficiency of processing bonfires with the production of plates with high operational and environmental parameters.

The technical result from the use of the invention is to obtain low-toxic finishing boards with high water resistance, which is determined by the indicator - swelling in thickness in 24 hours.

This technical result is achieved due to the proposed press composition for the formation of finishing plates containing flax bonfire, urea-formaldehyde resin KF-NU, polyvinyl acetate dispersion and hardener - ammonium chloride, in the following ratio of components, wt.% On dry matter:

Flax bonfire 87.3-91.4 Urea-formaldehyde resin KF-NU 5.4-8.3 Polyvinyl Acetate Dispersion 1.1-3.4 Ammonium chloride 0.9-1.2

wherein the press composition in which the mass ratio of flax bonfire: crushed flax bonfire = (9-7) :( 1-3).

Obtaining low-toxic finishing boards from the proposed press composition is achieved by the introduction of ingredients - polyvinyl acetate dispersion and hardener of ammonium chloride, which bind free formaldehyde. The formed plates have a low formaldehyde content and belong to the E1 class of formaldehyde emission, which meets the requirements of the international standard.

In combination with a flax bonfire, these ingredients simultaneously increase the water resistance of the tiles, which is determined by the swelling rate of the plate in 24 hours.

Flax bonfire in the composition is used without additional processing or in combination with chopped flax bonfire to an average size of 5-10 mm with a mass ratio of flax bonfire and chopped bonfire (9-7) :( 1-3).

The invention is illustrated by the following examples. A flax bonfire is loaded into the mixer, a pre-prepared mixture in a predetermined quantity containing a hardener - ammonium chloride, urea-formaldehyde resin KF-NU (TU RB 00204547.075-96) and 20-50 wt.% Polyvinyl acetate aqueous dispersion is fed through pressure nozzles. The press composition is mixed for 15-20 minutes until the flax fires are evenly distributed, poured into the mold, a layer defined by thickness is formed and pressed in two cycles. The duration of the first cycle is 25-30 minutes at a pressure of 250-300 atm and a temperature of 115-120 ° C, the second - 10-15 minutes at the same pressure and temperature of 140-150 ° C.

The nominal dimensions of the plate are:

Thickness 10 to 25 mm +/- 0.3 Long 1800 mm +/- 5.0 Width 1200 mm +/- 5.0

Flax bonfire is used with chopped flax bonfire up to 5-10 mm with a mass ratio of (9-7) :( 1-3), while the surface structure of the plate becomes more even and smooth.

Specific examples are presented in the tables. Table 1 shows the specific composition of the press composition of the examples. Table 2 presents the physico-mechanical properties of the finishing plates.

Changing the quantitative ratios of the ingredients of the press composition in the direction of decreasing or increasing does not achieve a technical result.

As can be seen from table 2, for plates from the proposed press composition, in comparison with the closest analogue, the swelling in thickness over 24 hours decreased by 2 times and amounted to ~ 11%. The formaldehyde content (mg per 100 g of absolutely dry plate) in these finishing plates is less than 8.0 including, which corresponds to the emission class of formaldehyde E1 - up to 8.0 including, and the plates in the comparative example correspond to the emission class of formaldehyde E2 - over 8, 0 to 30 including.

Thus, the finishing plates formed from the proposed press composition have high moisture resistance and are low toxic, which allows them to be widely used without additional cladding in the furniture and construction industries.

Table 1 The composition of the press composition for the formation of finishing plates Components wt.% On dry matter Examples p / p one 2 3 four 5 6 7 Flax bonfire 91.1 63.0 89.1 87.3 91.4 81.9 90.3 Flax bonfire shredded - 26.9 - - - 9.1 - Urea-formaldehyde resin KF-NU 6.8 6.6 8.3 8.1 6.6 5,4 - Urea formaldehyde resin - - - - - - 8.4 Polyvinyl Acetate Dispersion 1,1 2.6 1.4 3.4 1,1 2.7 - Hardener - ammonium chloride 1,0 0.9 1,2 1,2 0.9 0.9 1.3

table 2 Physico-mechanical properties of the tiles The name of indicators Examples p / p Comparative AC No. 859191 one 2 3 four 5 6 7 Density, kg \ m ³ 550 850 500 600 620 700 650 Thickness swelling in 24 hours (sample size 100 × 100 mm)% no more 12 9 eleven 12 13 10 22 Tensile strength, MPa, not less 0.42 0.46 0.43 0.42 0.41 0.44 0.30 Formaldehyde content, mg per 100 g, absolutely dry plate 6.1 4.3 6.9 6.3 5.9 5,6 32 Plate thickness, mm 9.9 10 10.1 10 10 9.9 10.1 Mass ratio of flax bonfire: crushed flax bonfire - 7: 3 - - - 9: 1 -

Claims (2)

1. Press composition for the formation of finishing plates containing a flax bonfire, urea-formaldehyde resin KF-NU, polyvinyl acetate dispersion and hardener - ammonium chloride, in the following ratio of components, wt.% On dry matter:
Flax bonfire 87.3-91.4 Urea-formaldehyde resin KF-NU 5.4-8.3 Polyvinyl Acetate Dispersion 1.1-3.4 Ammonium chloride 0.9-1.2 2. The press composition according to claim 1, in which the mass ratio of flax fire: crushed flax fire = (9-7) :( 1-3).