CS261841B1 - A method of producing thin hard fibreboards made of soft non-pressed wood fiber materials - Google Patents

Abstract

Soft, unpressed wood fiber sheets are pressed individually or in a set between flat plates at a temperature of 200 to 225 degrees Celsius, a specific pressure of 5 to 7 MPa and a time of 45 to 420 seconds.

Description

The invention solves a process for the production of thin "hard fibreboards" from soft non-pressed fibreboards.

Nowadays, large-area fibreboard that is smooth on both sides is produced on large-capacity wood-based lines in the form of industrial flat wood, chips, etc. with the addition of glue.

The disadvantage of this method is that large volumes of production are needed, because at smaller volumes production is unprofitable. Due to the large format of fiber boards required for production profitability, it is not possible to maintain the thickness of the boards within the tolerances required by some processing industries, e.g. automotive industry, without additional thickness equalization by grinding, which requires further operation, production of equipment and in particular means loss of wood mass. Another disadvantage of the described process is the hygienic defect due to free formaldehyde leakage and the environmental problems associated with the addition of the adhesive during manufacture.

The above-mentioned disadvantages of the prior art are overcome by the method of making thin hardboard from the non-molded wood fiber materials according to the invention, which is characterized in that the non-molded hardwood fiber that is individually pressed or stacked is pressed between equal payments at 200 to 225 ° C. a specific pressure of 5 to 7 MPa and a time of 45 to 410 seconds.

The process according to the invention allows for the compression of the finished, non-molded fiberboard into hard thin, double-sided smooth fiberboard with properties which are suitable for I. grade hard fiberboard.

Thus, the production method makes it possible to use excess volumes of the macrofibre board for the production of hard thin, double-sided smooth fiber boards in cases where the hard fibreboard is more desirable on the market than the macrofibre board. An advantage of the process according to the invention is that it ensures the production of hygienically sound boards and eliminates the negative ecological effects arising from the addition of glue in the conventional manufacture of hard fiber boards, which is a higher effect of the invention.

In accordance with the process of the invention, the non-compacted fiberboard in whole formats or in blanks, without further treatment, individually or stacked together, is joined together in a compact thatch between the straight plates of the hydraulic press under heat and pressure.

Claims (4)

SUBJECT A method for producing thin hard fibreboards of soft non-pressed wood fibers, characterized in that the soft non-pressed fibreboard is Example 1 Non-pressed fibreboard of 1 000 X 1 000 mm with 15 mm ridges of coniferous raw material without any prior treatment. it is inserted into the hydraulic press between the straight presses and pressed at a temperature of 225 ° C at a pressure of 6.0 MPa and a time of 50 seconds. This gives a hard, double-sided smooth fibreboard of 2.5 mm with a density of 1180 kg / m3. Example 2 Non-pressed fibreboard with a diameter of 2 240 X 1 220 mm of 20 mm ridges made of coniferous raw material without further treatment is inserted into the hydraulic press between straight pressing and pressed at 210 ° C at 6 MPa and for 120 seconds. This results in a hard, double-sided, 3 mm thick fibreboard with a density of 1,094 kg / m 3. Example 3 Crushed fibreboard of 2 240 X 1 220 mm thickness of 15 mm from coniferous raw material without further treatment is placed in a hydraulic press with straight pressing plates and pressed at 200 ° C at 6.5 MPa and for 175 seconds. This results in a hard, double-sided smooth fibreboard of 2.5 mm with a density of 1150 kg / m3. Example 4 Two non-extruded fibreboards of 2 000 X 1 000 mm with a thickness of 15 mm from coniferous raw material, without any pre-treatment and without the use of glue, are placed in a hydraulic press between the same and pressed at 210 ° C. pressure of 7 MPa and 360 seconds. 5 mm thick fibreboard with a density of 1180 kg / m 3 is produced. The thin hard fibreboard produced by the present invention is suitable for use in manufacturing industries where board ridge accuracy is increased, e.g., the automotive industry. They will also be used where there is a need for health and where a smooth surface is required, as well as wherever conventional DVDs are used. individually or in a set, they are pressed between flat plates at a temperature of 200 to 225 degrees Celsius, a specific pressure of 5 to 7 MPa and a period of 45 to 420 seconds.