UA54691A - Method for manufacture of construction low-toxic plates - Google Patents

Abstract

A method for production of construction low-toxic plates includes manufacture and drying of crushed wood particles or vegetable waste, mixing with urea-formaldehyde resin and carbamide, molding of a packet of chips, pressing and conditioning of plates. Into resin are introduced aqueous solution of carbamide, liquid glass and albuminous glue in amount from 1 to 10 % of dry substances from dry residue of resin. Crushed wood or vegetable waste before resinification are treated with aqueous solution of slaked lime in amount of 0,5 - 2,5 % of dry residue with respect to absolutely dry chips.

Description

Description of the invention

The invention relates to the woodworking industry and can be used in the production of 2 low-toxic construction boards, both from wood and vegetable waste from agricultural crops (flax stalks, hemp, straw, rape stalks, etc.) and urea formaldehyde resin used in construction. in transport, in the manufacture of furniture, and in other branches of the national economy.

There is a known method of production of chipboards by grinding wood, mixing 70 dried chips with urea-formaldehyde resins. Forming chip carpet, cutting it into sheets, pressing, hot pressing, cutting boards and stacking them (1 - prototype).

The disadvantage of the known method is the toxicity of chipboards, as the amount of formaldehyde released from the boards exceeds the requirements of sanitary and hygienic norms (more than 1 Ωg/100g of the board), as well as the use of a significant amount of carbamidoformaldehyde resins. 12 A known method of manufacturing chipboards, which includes mixing wood mass with a binder, processing the outer layers of the board with a plasticizer, forming a carpet, pressing and hot pressing. As a plasticizer, urea (urea) powder is used, which is injected together with a binder in the amount of 1.0 - 15.095 from the absolutely dry mass |21.

The disadvantage of the known method is the significant consumption of scarce and expensive phenol-formaldehyde resins, the toxicity of plates due to the emission of free phenol and formaldehyde. This leads to the prohibition of the use of such plates in residential and public buildings. Urea is introduced into the binder in the form of a powder for the outer layers, which interferes with obtaining a binder of sufficient density for applying it to the wood mass.

The invention is based on the goal of creating a method of manufacturing low-toxic building boards from wood or plant waste from agriculture, in which, by introducing additional components, 29 sequences and modes of technological components, it is ensured that the emission of free formaldehyde is reduced to "sanitary standards in residential premises. Also, the consumption of carbamide-formaldehyde resins is reduced. This will expand the field of use of urea formaldehyde resins.

The task is solved by the fact that in the method of manufacturing plates, including the production and drying of crushed wood particles or plant waste, mixing them with urea-formaldehyde resins and - urea, forming a chip bag, pressing and conditioning plates, according to the invention in Ge"! urea-formaldehyde resin is injected with an aqueous solution of urea, liquid sodium glass and protein glue in the amount of 1.0 - 10.00 mass of dry substances from the dry residue of the resin with the following ratio of ee, components, mass.9. "Its 3 urea 20-47 is) liquid sodium hydroxide 5-12 protein glue 0.5-3.0 water the rest "

The aqueous solution of the components is obtained by first dissolving protein glue, for example, casein glue in water, and then mixing the remaining components until they are completely dissolved. h Before tarring, particles of chopped wood or plant waste are treated with an aqueous solution of » slaked lime (milk of lime) in the amount of 0.5 to 2.5 wt. 9o of dry residue to completely dry shavings.

Particles of crushed raw materials are pitched with a prepared binder with an amount of ammonium chloride hardener of 395 to completely dry resin, and a capacity of resin in slabs of 995 from the mass of completely dry shavings. A chip bag is formed from 1 of the obtained mass, which is then pressed. The plate pressing temperature is 1857C, the pressing duration is 0.28 min/mm of plate thickness, the specific pressing pressure is 2.4 - 2.5 MPa. After pressing, the slabs are conditioned. (o) Table 1 shows the properties of the binder based on urea-formaldehyde resin KF-MT-15 with the addition of an aqueous solution of urea, liquid glass and protein glue with s 50 with different amounts of components to the dry residue of the resin. Table 2 shows examples of concrete compositions for the manufacture of "6 wood chipboards, their physical and mechanical properties with the application of an aqueous solution of lime with different amounts of dry matter to the wood chips before tarring, according to the invention and the prototype. An aqueous solution of urea, liquid glass and protein was introduced glue in carbamide-formaldehyde resin in the process of its approval binds the released formaldehyde up to two times, and also replaces the added amount of resin p" in the manufacture of boards. Processing of chips before tarring with an aqueous solution of lime partially fills the pores and irregularities of the particles of chopped wood, which reduces absorption in of carbamide-formaldehyde resin in the process of mixing the chips with the binder and transporting the chips - adhesive composition. The aqueous solution of lime applied to the chips during the process of pressing the plates and their subsequent conditioning binds free formaldehyde. Because the use of the proposed method, compared to the prototype, allows keep chipboards of formaldehyde emission class E-1 (up to 10 mg per 100 g of board) and reduce the consumption of carbamide-formaldehyde resin by 10 - 3095. However, an exaggeration of lime in the composition of the board can cause the release of formaldehyde. b5 -D-

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PI - shavings, mass.9o 77 ti o ch zvo 000 Mekamshutmya yuyu plates « yu Z s (Vmistformaldeplumitoog obi | 46/98 82 | 78186 174686 :z» Note: in the process of preparing the binder in carbomidoformaldehyde resin KF-MT-15 an aqueous solution was introduced in the composition by mass: urea - 45, liquid glass - 8, casein glue - 1.0, water - 46, in the amount of 5.095 absolutely dry substances from the dry residue of the resin. 395 References. and 1. Shvartsman G. M Production of chipboards - M.: Lesnaya promyishlenost, 1977, pp. 40 - 141.

Sg" 2. Author's certificate of the USSR, Mo1027051, V 29.5/00, 1983. (e)) p. 50

Claims (2)

The formula of the invention - Z y y y y 1. The method of manufacturing low-toxic construction boards, which includes the production and drying of crushed wood particles or plant waste, mixing them with urea-formaldehyde resin and urea, forming a chip bag, pressing and conditioning the boards, which is characterized by the fact that a 29% aqueous solution of urea is introduced into the resin, of liquid glass and protein glue in the amount of 17 to 10 95 dry substances from dry in. of the resin residue, with the following ratio of components, wt. 9o: urea 20-47 liquid sodium hydroxide 5-12 60 protein glue 05-30 water the rest. 2. The method according to claim 1, which differs in that the chopped wood or vegetable waste is treated with an aqueous solution of slaked lime in the amount of 0.5 - 2.5 95 dry residue to completely dry shavings before tarring. Official bulletin "Industrial Property". Book 1 "Inventions, useful models, topographies of integrated microcircuits", 2003, M Z, 15.03.2003. State Department of Intellectual Property of the Ministry of Education and Science of Ukraine. « «- (22) (Se) « IS in) - with . and? 1 sh" (22) at 50 - 60 b5