CS268567B1 - Thickness of agglomerated lignocellulosic material - Google Patents

Abstract

Doaks according to solution included! 86.37 to 92.74% haot. of lignocellulosic material, 7.0 to 12 wt.% urea formalin and hyde condensate, 0.25 to 0.43% by mass. of ammonium chloride and 0.007 to 1.2 wt.% surfactants such as oxyethylene alkylphenols and fatty alcohols, amides of ethylenediaminetetraacetic acid and nitrilotriacetic acid, condensates of fatty acids with amino acids and polyamines, alkylarylsulfonates and sulfobetaines

Description

The invention relates to boards of agglomerated lignocellulosic material containing surfactants.

Hitherto known thatches of agglomerated material, for example chipboard docks, sawdust docks, sheathing boards, wood-fiber boards that are made using urea-formaldehyde adhesives, release harmful formaldehyde into the environment to an increased extent. The release of formaldehyde from agglomerated boards, even several years old, is caused by the hydrolysis of the urea-formaldehyde adhesive by the effect of heat and moisture in the plates. The release of formaldehyde causes great difficulties in the mass use of mainly chipboard boards in furniture production and in the state of mining. At present, thatches of agglomerated material with fogged formaldehyde emissions are known, which contain! in addition to the lignocellulosic material and urea-formaldehyde adhesive components of the usual composition, also additional conglomerates which are added to the plates in order to reduce the emission of formaldehyde therefrom. Various nitrogen compounds such as urea are used (Ikeda M .; Japanese Patent 74.18926, Kawahara N.; Japanese Parent 73.72309), Mel Amine (Ideda M .; Japanese Patent 74.18926, Slezyngier W .; et al .; Polish Patent 74060, 1975. Guanidine and its derivatives (Niskina S .; Japanese Patent 73,92541), thiourea, dicyandiamine, caprolactamine, m-phenylenediamine (Starzynská K .; Polimers 18/12/639, 1973), aliphatic and aromatic azo compounds, ammonium salts of carbonic acid ( Kellner et al .; AO ČSSR 206094) as well as oxygenated sulfur compounds, ammonium sulfide and polysulfides (Neumann R .; NSR patent 2130677, 1971), IIInosulfonates (Ludvig C., Staut AW; U.S. Pat. No. 3,686,838; Kubín J. et al. AO ČSSR 167432, 1977), amino compounds such as urea, ammonia thiourea with water-soluble alkaline earth metal salts using an acid catalyst from the group of acids and their hydrolyzable salts (Černý J., AO ČSSR 178637, 1975) or an excess of urea and ammonium chloride ( Kawahara N .; Japanese Patent 73.72309). Hubatsch H * et al. (AO ČSSR 234437, 1983) prepares a urea-formaldehyde adhesive at a higher molar ratio of amino groups to aldehyde groups. An amino compound, especially urea, is added to the adhesive thus produced in a known manner. Also by the action of ammonia gas on finished agglomerated thatches (Charles S .; Plywood and Panel 4, 1982, 8-9) or ammonia and released from ammonium hydroxide (Roíael E. Miertzsch H., Menzel W .; Adhazion 26/3 /, 1982 , 18-23) and reduces formaldehyde emissions from highly permeable lingnocellulosic materials. The disadvantage of the described methods is the deterioration of the ratio of nitrogenous substances to formaldehyde, which results in the deterioration of the physical and mechanical properties of the agglomerated boards resp. the achieved effect of reducing formaldehyde leakage is low. Some applications are disadvantageous from economic or operational knowledge.

The disadvantages of the current state are eliminated by thatched agglomerated surfactant-containing lignocellulosic material according to the invention, the essence of which is that they contain 86.37 to 92.74% by weight of lignocellulosic material, 7.0 to 12.0% by weight, of urea-formaldehyde condensate. 25 to 0.43% by weight of ammonium chloride and 0.007 to 1.2% by weight. surfactants such as oxyethylene alkylphenols, exethylene fatty alcohols, ethylenediaminetetraacetic and nitrilotriacetic acid amides, fatty acid condensates with amino acids and polyamines, alkylarylsulfonates and sulfobetaines.

Fopísané agglomerated thatch from lignocellulosic material, such as fiberboard boo, sawdust plate Pazderová plate fiberboards according to the invention ¹ are expanded release a reduced amount of formaldehyde in the environment, the physical and mechanical properties are not altered. After ventilation, the removal of the formaldehyde released during the pressing of the boards from the agglomerated lignocellulosic material of the knee may result in a concentration of formaldehyde released into the air of up to 0.1 .mu.g of aldehydes / .mu.l of water, which results in a higher effect of the invention. The data apply to the conditions of determination of the formaldehyde released by the two-hour desiccator method. According to Myersa E., (Forest Prod. J., 33, 1983, No. 4, 27-37) and according to Sundin B. (IUFRO World Congress, South Africa 9, 1986) 0.25 .mu.g of formaldehyde / ml of water corresponds to emission limit value E ^ Special, CS 268 567 B1 (ie 5 .mu.g formaldehyde / 100 g chipboard determined by the perforator method) and 0.65 pg formaldehyde / ml water corresponds to the limit value of triode E ^ ·

The advantages of agglomerated lignocellulosic material and surfactant-containing boards according to the invention with reduced formaldehyde emissions will make it possible to use aglocerized boards in construction to an increased extent, mainly as a replacement for phenol-formaldehyde chipboards in building interiors and to improve the hygiene of furniture products.

Example 1

Three-layer chipboard containing 90.37% by weight, wood material, 9.2% by weight, urea-formaldehyde condensate, 0.33% by weight, ammonium chloride and 0.1% by weight, a mixture of surfactants consisting of 65% by weight, oxyethylene alkylphenol and 35% by weight. % by weight of oxyethylene fatty alcohol, after venting the formaldehyde released during pressing, under the conditions of the two-hour desiccator method, releases 0.15 .mu.g of formaldehyde / ml of water, which complies with emission class E. Special, Example 2

Pazder plate containing 91.67% by weight, lignocellulosic material, 8.0% by weight, urea-formaldehyde condensate, 0.29% by weight, ammonium chloride, 0.04% by weight, surfactants composed of 50% by weight, nitrilotriacetic acid amide and $ 50. mass, the fatty acid condensate with amino acids releases, under the conditions of determination as in Example 1, 0.45 .mu.g of formaldehyde / ml of water, which complies with the emission class E2.

Example 3

Sawdust board containing 87.6% by weight, wood material, 11% by weight, urea-formaldehyde condensate, 0.4% by weight, ammonium chloride and 1.0% by weight, surfactants consisting of 22.7% by weight, oxyethylene alkylphenol and 77% by weight .3% by weight of a condensate of fatty acids with polyamines releases, under the conditions of the determination as in Example 1, 0.1 .mu.g of formaldehyde / ml of water, which complies with the emission class Special.

Plates of agglomerated lignocellulosic material containing surfactants with reduced formaldehyde emissions according to the invention can be produced in the woodworking industry.

Claims (1)

SUBJECT. -OPCENT OF THE INVENTION Plates of agglomerated lignocellulosic material containing surfactants with reduced formaldehyde emission, characterized in that they contain! 86.37% to 92.74% by weight of lignocellulosic material, 7.0 to 12% by weight of urea-formaldehyde condensate, 0.25 to 0.43% by weight of ammonium chloride and 0.007% to 1.2% by weight of surfactants such as oxyethylene alkylphenols, oxyethylene fatty alcohols, ethylenediaminetetraacetic and nitrilotriacetic acid amides, fatty acid condensates with amino acids and polyamines, alkylarylsulfonates and sulfobetaines.