CS276346B6 - A method of producing waterproof chipboard thatch - Google Patents

Abstract

The solution relates to a method of producing a water-resistant particleboard consisting of inner and outer layers with a reduced degree of flammability, including mixing the components, pre-pressing, pressing, formatting, thickness equalization and air conditioning. The essence of the solution is that phenol-formaldehyde glue in an amount of 10 to 12% by weight is applied to a mixture consisting of 65 to 85% by weight of surface chips and ]> to 30% by weight of ammonium dihydrogen phosphate in a solid state and 7 to 11% by weight of phenol-formaldehyde glue aa is applied to a mixture consisting of 70 to 95% by weight of central chips and 5 to 30% by weight of ammonium dihydrogen phosphate in a solid state. The boards produced in this way can be used as structural elements in wooden structures.

Description

r 1 EN 276 346 B6

SUMMARY OF THE INVENTION The present invention provides a method for producing a waterproof particleboard with a reduced flammability rating for general use in enhanced fire safety conditions.

The prior art methods of retarding particleboard have been directed to their own structural material by priming a certain proportion of the mineral substances which flame retardant, impregnate the chips with retardant solutions, and finish the coated particle board with paints or layers of non-wood materials with retarding effects. When reducing the flammability of chipboard boards by impregnating dry or moist damps, this is a very laborious, lengthy, technologically, energy-intensive and economically demanding treatment process, and shrubs report good retardation results.

The application of a surface coating or a layer of non-wood material to the finished particle board is an operation that is relatively unpretentious but reduces the flammability effect. Despite the fact that water-retardant substances with PVC dispersions and non-combustible non-wood-based materials with the possibility of application of chipboard surface coatings currently exist, their effectiveness decreases by mechanical damage.

These drawbacks are avoided by the production of a waterproof chipboard consisting of inner and outer layers of reduced flammability, including component mixing, preforming, molding, thicknessing, and air conditioning according to the invention, wherein the phenol formaldehyde adhesive is 10-12% by weight . is applied to a mixture consisting of 65 to 85 wt. surface chips and 15 to 35 wt. solid ammonium dihydrogen phosphate and 7 to 11 wt. of a phenol formaldehyde adhesive is applied to a mixture consisting of 70 to 95 wt. % of central chips and 6 to 30 wt. solid ammonium dihydrogen phosphate.

For the production of water-resistant three-layer chipboard, chips prepared for this purpose from wood raw material on chopping machines, or chips, chips, shavings and debris which are waste material from other wood processing can be used. Treated and dried chips should have 2 to 6% moisture according to the use of the individual layers of waterproof chipboard. The water-resistant particle board is molded from chips with a surface chip adhesive of 10 to 12% for the central chips 7 to 11% at a press temperature of 150 to 180 ° C and the overall pressing process is dependent on density, thickness and moisture particle size. The total pressing time is given by the sum of the overheating time of the chipboard, which is dependent on the thickness of the chipboard, the moisture and the temperature and time required to cure the adhesive. After molding, the particleboard is typically formatted, thicknessed, air-conditioned and shipped. An advantage of the method of producing water-resistant particle boards with reduced flammability according to the present invention is that it is not in principle necessary to change the process equipment in their manufacture. A further advantage is the reduction of the specific compression pressure of 0.1 to 1.0 MPa. The advantage of the particle board produced in accordance with the invention is the improvement of the degree of flammability, absorption and thickness swelling while maintaining the mechanical properties according to the requirements of the relevant standards. The method according to the invention can also be used for extruded particle board. Example 1

A water-resistant three-layer chipboard was produced with a density of 780 k.g.nT ^ of a wetness of 8%, with a weight ratio of surface chips to center 3/8: 5/8, in the surface layers to a mixture consisting of 70 wt. parts of surface tread 30 wt. parts of ammonium dihydrogen phosphate deposited with 11% phenol-formaldehyde adhesive in a central layer consisting of a mixture of 70 wt. parts of central chips and 30 parts by weight of ammonium dihydrogen phosphate deposited with 10% of phenol formaldehyde adhesive. It was

Claims (2)

with a paraffin emulsion coating of 1.0%. The total thickness of the waterproof, chipboard was 19 mm. The maximum pressing pressure was 2.5 MPa, the total pressing time of 6.5 mins the pressing temperature was 175 ° C. The produced waterproof chipboard retained the mechanical properties specified by ČSN 49 0165 Chipboard Docking - Method of Determining the Bending Strength and ČSN 49 0172Tensile Strength of Tensile Strength Perpendicular to the Deck Plane and Has Improved Physical Properties Specified by ČSN 49 0164 Determination of Physical and Mechanical Properties chipboard - Absorption, moisture and swelling, compared to commonly produced phenol-formaldehyde chipboard. The fire-technical properties were tested by the flammability test according to ČSN 73 0862, where the treated water-resistant particle board was included in the flammability class A. The non-treated particle board is classified in the degree of flammability - C2. Example 2 A waterproof drp / abrasive plate was produced as in Example 1 with a reduced content of pure ammonium dihydrophosphate in the central layer (90 parts by weight of central chips and 10 parts by weight of ammonium dihydrofuran). The waterproof chipboard treated in this way has been classified as flame retardant B. The retardation treatment can also be carried out with single-layer or 5-layer water-resistant particle boards. The accompanying table lists the technical properties of the waterproof particle board produced according to the present invention. These dockings request the CSN. A waterproof chipboard with a reduced flammability rating may be used as a structural element in timber construction; by its use it will be possible to increase the fire safety level of wooden buildings. Waterproof chipboard with a reduced flammability rating can be used to produce various transport and other wood cells, which will then be included in a higher degree of fire safety. Another possibility of using a waterproof particleboard with a reduced flammability rating is combined! with suitable retardation coating, e.g., retardant or foil coating compositions. Such treated large-area material can fulfill the purpose of design, protection and decoration in wooden structures. PATENT REQUIREMENTS A method for producing a waterproof particle board consisting of inner and outer layers with reduced flammability, including component mixing, preforming, molding, formatting, thickness equalization, and air conditioning, wherein the phenol-formaldehyde adhesive is 10-12% wt. is applied to a mixture consisting of 65-85 wt. % of surface chips and 15 to 35 wt. ammonium dihydrophosphate in solid form and 7 to 11 wt. of the phenol formaldehyde adhesive is applied to a mixture consisting of 70 to 95 wt. % of central chips and 5 to 30 wt. ammonium dihydrate in a solid group. In CS 276 346 B6 Technical Properties of Waterproof Particle Boards Characteristic Light Reducing Plate According to Example 1 Plate with Reduced Flammability According to Example 2 Thickness (mm) 19.0 19.0 Density (kg.m 3) 780 780 Bending Strength (MPa) 17.71 18.21 Tensile Strength Perpendicular to Thickness (MPa) 0.53 0.59 Thickness 2 hours (%) 1, 64 1.96 PO 24h (%) 4.56 5.35 water absorption after 2 hours (%) 10.59 11.01 after 24 hbd (%) 24.36 27.29 Flammability rating according to ČSN 73 0862 AB