CS241589B1 - Celobuková waterproof plywood - Google Patents

Abstract

The invention belongs to the field of wood technology. All-beech waterproof plywood with improved fire-technical properties, glued with phenol-formaldehyde resin modified with 2,6-xylenol. It is classified as a B flammability class, while maintaining other physical and mechanical properties required for classic all-beech waterproof plywood. The plywood is produced without changing the technology and without the need to purchase additional equipment, increase the consumption of electrical and thermal energy. Possibilities of use for the production of wooden structures and in the mining industry.

Description

The invention falls within. Wood Technology Department.

Full-body water-resistant plywood with improved fire-technical properties, glued with phenol-formaldehyde resin treated with 2,6-xylenol. It is classified to the degree of flammability B, while maintaining the other physical-mechainic properties required for the classic all-beech water-resistant plywood. Plywood is produced without changing technology and without the need to purchase additional equipment, increasing the consumption of electrical and thermal energy. Possibilities of use for production of wooden structures and in mining industry.

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The present invention solves the composition and process for the production of cellular waterproof plywood with improved fire-technical properties for use in the construction and mining industries.

The prior art methods of retardation treatment of plywood are focused on the treatment of the construction material itself, mainly the impregnation of veneers with solutions of retardants and surface treatment of finished plywood by coating and retarding effect.

In reducing the flammability of plywood by impregnation of dry or wet veneers, these are from the technological point of view a laborious, technologically, energetically and economically demanding way of treatment.

Nevertheless, literary sources report good retardation results. The application of the surface coating to the finished plywood makes the operation relatively technologically undemanding, but the flame retardant effect is less. Although there are currently relatively perfect retardants, based on aqueous solutions of PVAC dispersions, their effectiveness decreases by mechanical damage to the coating.

These drawbacks are overcome by an all-beech water-resistant plywood with improved fire-technical properties consisting of veneers glued with phenol-formaldehyde resin, which consists in that the adhesive consists of 70 to 75% by weight of phenol-formaldehyde resin and 25 to 30% by weight of phenolic anttoxide , 6-xylenol.

An advantage of the solid beech plywood according to the invention is that it has good physico-mechanical properties. Compared to the plywood produced so far, it has improved fire-fighting properties - it is classified in flammability grade B, while it was originally classified in flammability grade C2.

In the production of these plywood it is necessary to change the production technology, to invest additional machinery equipment (eg. For i, veneer mpregnáciu etc.) to increase the workforce and to increase the consumption of electrical and thermal energy.

Example

The plywood was glued with phenol-formaldehyde resin, to which 30% of phenolic antloxidant - Anttoxidant - * - Chematox AO 49 - manufactured m. p. Chemko Strážske. Beech veneers with a thickness of 1.8 mm were used in the manufacture of plywood, counting nine, the total thickness of the plywood after pressing 15 µm.

The specific compression pressure was 1.8 MPa. In the manufacture of the plywood, the molding temperature was 130 degrees C so as not to cause partial decomposition of the retarders. The total pressing time was 16 minutes and the adhesive mixture was 190 to 200 g. m ~ ² .

The plywood produced retains the required physical and mechanical properties with the same characteristics as the plywood glued with phenolic resin without the addition of retarders. Properties were tested according to ČSN 49 0170-9. Adhesion was tested by AW 100 test according to DIN 68 705 and retained in

I. quality group.

The fire-technical properties were tested by the flammability test according to ČSN 73 0862, where the treated plywood was classified in the degree of flammability B. Untreated plywood is classified in the degree of flammability C2.

Waterproof all-beech plywood with reduced flammability can be used for the production of wood glued beams as a co-instruction element, and by using it will be possible to increase the degree of fire safety of wooden buildings.

Waterproof solid beech plywood can be used for partition walls and walls of wooden buildings, which also ensures an increased degree of fire safety. Furthermore, for the production of various transport and other wooden cells, which can then be assigned to a higher degree of fire safety.

Another possibility of using a retarded waterproof plywood is in combination with a suitable retarding or even decorative finish - for example by coating or foil. Such modified large-area material can fulfill the purpose of construction, protection and decoration in wooden buildings of various kinds.

Claims (1)

SUBJECT All-beech water-resistant plywood with improved fire-technical properties, consisting of veneers glued with phenol-formaldehyde resin, characterized in that the adhesive forms! 70 to 75% by weight of phenol-formaldehyde resin and 25 to 30% by weight of phenolic antioxidant having a 6% by weight content of 2,6-xylenol.