A method of manufacturing a biostable fibreboard

 

(57) Abstract:

Use: in the production of firm wood-fiber plates in the wet. The inventive form the wet plate method. Dried. Not obverse side of the dried plate was washed with antiseptiruyuschimi solution heated to a temperature of 60-80°C with simultaneous pressing. Then the plate is additionally podpisovat with simultaneous heat treatment at a temperature of 90-120°With multiplicity operations 3-7. As antiseptiruyuschimi composition using a mixture of aqueous solutions of ammonium silicofluoride and surfactant at a ratio of 1:1. table 1.

The invention relates to woodworking industry and can be used in the production of solid hardboard wet.

A known method for the production of wood-fiber plates by processing wood fiber antiseptic in the formation of the carpet on the casting machine. Antiseptic injected directly formed on the carpet through the top surface in the area of the suction part of the casting machine and through the bottom before the last spin at a relative humidity of 60-70% [1]

The disadvantage of this method nachitalas and at the time of the first phase of hot pressing (squeezing). When specific pressure of 55 kg/cm2and the temperature of the pressing 200aboutWith over 50-60 C is pressed the main quantity of water from wood-fibre carpet in the process. When this contaminated wastewater enterprise substances are difficult to clean and has high toxicity. If losses are high, the antiseptic in the waste water, it remains in a wood-fiber plate is not enough to ensure its biostability.

A known method of manufacturing a biostable solid wood slabs with a thickness of 3.2 mm wet process by impregnation not obverse surface of wood-fiber material with an antiseptic solution consisting of a mixture of aqueous ammonium silicofluoride with a concentration of 20-35% aqueous solution of surface-active substances on the basis of monoalkylphenols ether of polyethylene glycol with a concentration of 0.75 to 1.25% at a ratio of 1:1. Impregnation not obverse surface of the material is carried out after drying the plates at a temperature of antiseptic solution 60-80aboutWith every 3-7 times with simultaneous pressing in each cycle [2]

The disadvantage of this method is the impossibility of its use in the manufacture of biostable solid grovesnor the solid fiberboard thickness of 6-8 mm, which is the basic building material in standard wooden construction, this method provides the depth of impregnation antiseptiruyuschimi the solution is not more than 30% of the plate thickness. The depth of impregnation of the material does not ensure the desired biological, additionally, it causes warping of the material, which leads to loss of strength properties of the plate.

The purpose of the invention improve the depth of impregnation with simultaneous improvement of physico-mechanical properties of the plate.

This objective is achieved in that in the known production method biostable wood-fiber plates, which consists in forming plate, drying her with the subsequent cyclic impregnation not obverse surface of the plate with a mixture of 20-40% aqueous solution of ammonium silicofluoride and 1.0-1.5% aqueous solution monoalkylphenols ether of polyethylene glycol at a ratio in a mixture of 1:1, heated to a temperature of 60-80aboutWith simultaneous pressing in each cycle, according to the invention. After each impregnation cycle additionally perform thermal processing plate at a temperature of 90-120aboutWith simultaneous pressing. The necessary duration of the process of soaking and termoobrezan edowski examples (see table).

P R I m e R 1. Made of firm wood-fiber plate thickness of 6 mm wet method of production on the production line "Semak". On not obverse surface of the finished plate is applied preheated to a temperature of 60aboutWith the antiseptic solution consisting of a mixture of aqueous ammonium silicofluoride with a concentration of 20% aqueous solution of surface-active substances on the basis of monoalkylphenols ether of polyethylene glycol type OP-10 GOST 8433-81 with a concentration of 1.0% at a volume mixing ratio of 1:1.

Application antiseptiruyuschimi solution is performed by means of rubber rollers with simultaneous pressing. Then the plate is subjected to heat treatment with simultaneous pressing. The heat treatment is carried out by a pair of heated rollers to a temperature of 90aboutC. the Above sequence of operations is repeated 3 times.

Then fiberboard condition and determine the content of ammonium silicofluoride according to THE 13-0273643-15-90 and indicators of physical and mechanical properties in accordance with GOST 19592-80, the depth of impregnation antiseptic plate thickness is determined by the test method.

P R we analogously to example 1.

P R I m e R s 18-31. Analogously to example 1 the manufacture of plates in the range of transcendent values of the concentration of aqueous solutions of the components antiseptiruyuschaya mixture (18-23), temperature antiseptiruyuschimi composition (24-27), heat treatment temperature (28-31).

The table shows that the method of manufacturing a biostable wood-fiber plates in examples 1-17 allows you to ensure the content of ammonium silicofluoride in the slab is not less than 0.75% by weight of the abs. dry.plate that provides the desired level of biological stability. The depth of impregnation plate thickness 100% that provides high strength properties of the plate.

Examples 18, 19 show that the decrease in the concentration of a solution of ammonium silicofluoride below the proposed level does not provide the necessary content of antiseptic in the plate and 100% saturation depth, which reduces the strength.

To use the concentration of the solution ammonium silicofluoride above 40%, it is due to the fact that this concentration is the threshold of solubility of the ammonium silicofluoride.

In examples 20, 21 taken insufficient concentration of the surfactant, resulting in the observed low wettability plate antiseptiruyuschimi composition that reduces the content of th surfactant solution, what causes excessive slip antiseptiruyuschimi composition for wood-fiber plate at the time of the pre-plate, and hence reduces the amount of antiseptic in the plate and simultaneously reduces the strength characteristics of the plate.

Examples 24, 25 show a decrease in the content of ammonium silicofluoride in the plate, due to lack of solution temperature for activation molecules antiseptic with its penetration into the plate.

Examples 26, 27 carried out with the temperature of the solution 90aboutWith that causes increased evaporation of antiseptic in the air and, as a consequence, the lack of it in the stove, the decrease of the strength indicators.

Examples 28, 29 carried out at a low temperature heat treatment 80aboutWith that not enough intensifies the process of impregnation plate and thus does not provide the depth of impregnation. Insufficient heat treatment is not plasticizes the material being processed from strength drop in the plate.

Examples 30, 31 carried by excessive temperature heat treatment, which causes the dominance of evaporation of the liquid over the process of its penetration into the plate, and this causes a lack of antiseptics in the plate and adversely affects the strength dormancy is of the plate, drying and subsequent cyclic impregnation not obverse surface of the plate with a mixture of 20 to 40% aqueous solution of ammonium silicofluoride and 1.0 to 1.5% aqueous solution monoalkylphenols ether of polyethylene glycol at a ratio of 1: 1 in the mixture, heated to 60 to 80oWith simultaneous pressing in each cycle, characterized in that, with the aim of increasing the depth of impregnation with the simultaneous improvement of physico-mechanical properties of the plate, after each cycle of impregnation additionally perform thermal processing plate at 90 120oWith simultaneous pressing.

 

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