CS210893B1 - Method for treatment of fibreboards by precipitation of vegetable oil water emilsion - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for treating wood fiber boards by precipitation of an aqueous emulsion of vegetable oils in a mass.

Wet fibreboard production is characterized in that the defibrated wood in the form of a water dispersion is dewatered on a dewatering machine and the resulting fibrous carpet is pressed onto the boards by high temperature and pressure.

During manufacture, a paraffin emulsion is added to the fiber dispersion as a hydrophobizing agent. The sheets produced in this way exhibit a fairly high water absorption and relatively low physical and mechanical properties.

In order to improve both the water resistance and the mechanical properties, the pressed plates are treated by impregnating still hot plates with vegetable drying oils by applying oil to the plate between rotating rollers. The amount of oil applied is controlled or adjusted. it is given by the speed of hot plates removal from the press tank.

The penetration of vegetable oil into the plate is given both by the feed rate and the temperature of the impregnated plates. This means that by gradually removing the plates from the press reservoir, the temperature of the plates decreases and thus the penetration is relatively lower.

The impregnation intake is eliminated and the impregnation process improves and cheaper the whole impregnation process by the method of treating wood-fiber boards by precipitation of an aqueous emulsion of vegetable oils in the mass according to the invention, which is based on the aqueous emulsion of drying oil. and possibly adding manganese, lead or cobalt resin soap, or dicyclopenta210893 dlen as oxidation accelerators ranging from 1% to 15% by weight, precipitates under the influence of weakly acidic electrolytes such as aluminum chloride, aluminum sulfate, potassium aluminum sulfate, and the like. A pH of less than 7 and the fiber dispersion with the precipitated emulsion are partially dewatered prior to compression.

The technical effect of the invention is that the addition of an aqueous emulsion of vegetable oil to the aqueous dispersion of wood fibers ensures perfect contact of the impregnating agent with the entire surface of the wood fiber, while achieving perfect impregnation of the fibers throughout the cross section of the board.

The advantages of the invention are then the uniformity of impregnation uptake and the possibility of accurate impregnation dosing, which improves and cheaper the entire impregnation process and ensures a homogeneous distribution of the impregnating agent throughout the cross-section of the board mass.

Water from the dewatering machine practically does not even contain traces of greasy impregnation components. The dosing of the vegetable oil impregnating agent with respect to the perfect dispersion in the mass of the board is very economical and achieves up to half the consumption compared to the surface impregnation on the already pressed boards, with the mechanical properties of the final product being at the same level.

EXAMPLE 1

Impregnating mixture consisting of

32,0 kg linseed technical oil

4.0 kg paraffin

10.0 kg oleic acid technical

100.0 kg domestic water

3.0 l of ammonia 26% technical is emulsified in an emulsifier at 80 ° C and after cooling to about 30 ° C it is pumped into a storage tank. A vegetable oil emulsion of the above composition is added to the wood pulp water dispersion through a metering device on a sizing cabinet, followed by the addition of an aluminum sulfate electrolyte solution until a pH of 4.2 to 4.5 is achieved, the emulsion is precipitated into wood pulp, followed by conventional dewatering machine.

Example 2

Impregnating mixture consisting of

30,0 kg linseed technical oil with addition of oxidation accelerator 1 to 3 wt. resin soap lead or manganese or cobalt • 3.0 kg paraffin

6, kg oleic acid technical

100.0 kg utility water 2.0 l of ammonia 26% technical is emulsified in the emulsifier under the same conditions as in Example 1, so that the method of dosing is similar. The electrolyte used to precipitate the emulsion onto wood fiber is aluminum sulphate or potassium aluminum sulphate until a pH of 4.2 to 4.5 is reached.

Example 3

Impregnating mixture consisting of

32.0 kg linseed oil copolymer with 15 wt. dicyclopentadiene as an oxidation accelerator 3.0 kg paraffin

6.0 kg oleic acid technical

100.0 kg domestic water

2,0 1 ammonia 26% technical

The preparation of the emulsion of said composition is the same as in the previous examples, as well as the method and technology of dispensing the emulsion into the wood fiber dispersion. A mixture of an aqueous solution of aluminum sulphate acidified with 10% sulfuric acid is used to precipitate the emulsion until the pH of the environment is 4.1 to 4.3, followed by conventional dewatering.

Claims (1)

SUBJECT OF THE INVENTION Process for treating wood fiber boards by precipitation of an aqueous emulsion of vegetable oils in a mass produced by a wet process from defibrated wood with the addition of a drying oil of linseed, castor oil and the like, characterized in that the aqueous emulsion of drying oil having a paraffin carrier in water emulsion. , lead, or cobalt, or dicyclopentadiene, as oxidation accelerators ranging from 1% to 5% by weight, is precipitated by the action of weakly acidic electrolytes such as aluminum chloride, aluminum sulphate, potassium aluminum sulphate and the like in environments with pH less than 7 and fibrous The emulsion precipitated emulsion is partially dewatered prior to compression.