CS235366B1 - Consolidation agent for wood protection - Google Patents

Description

The invention relates to a composition for increasing the strength, toughness and specific gravity of a damaged wood and solves the problem of poorly obtaining physico-mechanical properties without damaging the wood and without color and other visual changes such as gloss and overall surface appearance.

For the surface treatment and protection of wood are used products based on epoxy, polyurethane, alkyd, melamine-formaldehyde resins, nitrocellulose lacquers, or various combinations thereof. These agents protect the wood surface, increase its durability and performance, but do not protect the wood in the whole mass, but only surface. Such a protective coating containing a fungicidal component is disclosed in British Patent 1,124,297. U.S. Patent 3,979,354 describes a protective coating with a fungicidal component - an organic tin compound that is chemically bound to an epoxy polymer.

Known impregnating wood preservatives having good penetration capacity are produced on the basis of tar, gas and pyrolysis oils or other high-boiling proportions of petroleum distillation. The disadvantage of these compositions is that the wood varies considerably, does not increase its strength and toughness and is only short-term acting as it evaporates and washes out of the wood. Improvement of the properties of the impregnating agents has been achieved in part according to the invention AO 192 864, which solves the short-term preservation of the original color of the wood, good penetration into the mass and partly improves the water-repellency. The disadvantage is low weather resistance, which is manifested by darkening of treated wood after six to ten months, while not increasing the strength and toughness of the wood.

The strengthening means according to the invention improve the properties and eliminate their drawbacks. Its composition is as follows: 5 to 30 wt. % of an acrylate type copolymer, optionally with styrene, having a weight average molecular weight of 45,000 to 65,000; % aliphatic alcohol having 2 to 4 carbon atoms, 10 to 15 wt. % methylcyclohexanone, 1 to 15 wt. % ethyl acetate, 5 to 15 wt. % butyl acetate, 20 to 40 wt. % toluene, 20 to 50 wt. % of liquid hydrocarbons boiling in the range of 150 to 360 ° C, 0.1 to 10 wt. pentachlorophenol, optionally in admixture with bis-tributyltin oxide. This composition has the advantage over previously known compositions in that it penetrates very well into the wood mass, increases strength and toughness, increases water repellency and dimensional stability, preserves flood coloration of wood, does not wash out of wood and even after prolonged weathering, impregnated wood does not lose its flood properties, has high resistance to ultraviolet radiation and wood biologically protects.

The wood is impregnated with a reinforcing agent by matting, soaking for 24 to 48 hours, or by a vacuum-pressure process. The treated wood is allowed to dry at 20 ° C and 50 to 60% relative humidity for 10 to 12 days. The compressive strength in the fiber direction is increased by 15 to 25%, the compressive strength perpendicular to the fibers increases by 25 to 45%, the water absorption is reduced by 20 to 50%, depending on the type of wood and the degree of its biological damage.

Firming agent is suitable for the protection of wood healthy or damaged by biological pests - insects, fungi, rot. It is suitable for the treatment of historic wood pulps, which are always significantly damaged by biological pests. It is advisable to treat such wood by soaking it in a firming agent so that it penetrates perfectly into the whole mass of the wood, reinforcing it and at the same time protecting it against biological corrosion. The advantage of this means is that the impregnated wood retains its flood coloration, which is very important especially when restoring historical wooden monuments.

The reinforcing agent is suitable for impregnating wood products such as cottages, wood paneling, windows and other wood-based products. Compared to classic wood varnishes, it has the advantage that it penetrates well into the wood and does not form a continuous varnish coating on its surface, as this is broken, cracked and peeled off due to weathering. Wood coated with a reinforcing agent has better weather resistance than the known compositions and has the advantage that maintenance of the treated wood is very easy to carry out, since the previous coating does not need to be removed, as with paints, but it is sufficient to clean the wood from dust. and abbot paint.

Examples of use

Example 1

The spruce wood damaged by the biological pests is impregnated by soaking in a firming agent having the following composition: 13 9 wt. a styrene-methyl methacrylate copolymer with a roofing molecular weight of 45,000 is dissolved with stirring at 20 ° C in a mixture of organic solvents of the composition: 6 wt. % aliphatic alcohol with 2 carbon atoms, 12 wt. % methylcyclohexanone, 2 wt. % ethyl acetate, 22 wt. % toluene and 42 wt. % of liquid hydrocarbons boiling in the temperature range of 150 ° to 360 ° C and 3 wt. pentachlorfemolu.

Dipping biologically damaged wood for 24 hours followed by drying at 20 ° C and relative humidity of 55% for 240 aSA will increase the wood compressive strength in the fiber direction by 40%, while preserving the original appearance of the wood as gloss and color.

Example 2

Beech wood damaged by the woodworm is treated with a double coating of a firming impregnating agent having the following composition: 20 wt. butyl methacrylate-methyl methacrylate copolymer with a weight average molecular weight of 650000, is dissolved under stirring at 40 ° C in a solvent mixture of the composition: 10 wt. % ethyl acetate, 15 wt. % butyl acetate, 5 wt. % aliphatic alcohol having 4 carbon atoms, 47.9 wt. % xylene and 2 wt. % of bis-tributyltin oxide and 0.1 wt. pentachlorophenol.

The treated wood is allowed to dry for 11 days at 20 ° C. The compressive strength of the wood is increased by 25% and the water absorption in water is reduced by 30% compared to untreated wood.

Example 3

Undamaged, healthy pine wood is treated with a double coating with a firming agent, which has the following composition: 5 wt. of a styrene-metayl methacrylate copolymer with a weight average molecular weight of 55,000, 18 wt. % butyl acetate, 20 wt. % ethyl acetate, 15 wt. % toluene, 37 wt. % xylene, 3 wt. % pentachlorophenol and 2 wt. bistributylcínoxidu.

After the first coating, the thatch is allowed to dry at 20 ° C for 72 hours. After this time a second coat is applied and the thatch is left to dry for 240 hours. In this way, the service life of the wood is increased 6-fold.

Claims (3)

SUBJECT A wood preservative comprising 5 to 30 wt. % of an acrylate type copolymer, optionally with styrene, having a weight average molecular weight of 45,000 to 65,000; % aliphatic alcohol having 2 to 4 carbon atoms, 10 to 15 wt. % of methyl tert-cyclobhexanone, 5 to 20 wt. % ethyl acetate, 5 to 15 wt. % butyl acetate, 20 to 40 wt. % toluene, 20 to 50 wt. % of liquid hydrocarbons boiling in the range of 150 to 360 ° C, and 0.1 to 10 wt. pentachlorophenol optionally in admixture with bis-tributyltin oxide.