DD203701A1 - METHOD FOR PRODUCING POLYMER TIMBER COMBINATIONS - Google Patents

Abstract

The invention relates to a process for the production of polymer-wood combinations, which are characterized by improved performance compared to untreated wood. The method consists of drying dry wood with the solution of a polymer and then removing the solvent from the wood by known methods. After removal of the solvent, a polymer film remains, which makes the wood hydrophobic and preserved against external influences. When crosslinkable polymers are used, irradiation with ionizing radiation can also lead to an improvement in the wood properties with regard to hardness and abrasion resistance.

Description

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Process for the preparation of poly-wood combinations Field of application of the invention

The invention relates to a process for producing clay polymer-wood combinations, which are distinguished by improved performance properties.

Characteristic of the known technical solutions

Process for the preparation τοη polymer-wood combinations are known · Already in the 30-iger years wood with phenolbzw. Urea resins impregnated, but this did not bring satisfactory improvements in wood properties. Only the introduction of the impregnation of trookenem wood with vinyl monomers and their polymerization with the aid of gamma radiation has led to good results (US Pat. No. 3,077,417, SU copyrights 122,219 and 126,562). Other monomers have also been used later on, for example styrene, methyl methacrylate, vinyl acetate, unsaturated polyester resins and combinations of various monomers (for example Jad.energie JMS (1970), H. 7, page 228 and H, 8, S). 261; Proceedings of the 9th Japan Conference on Radioisotopes, Tokyo 1969; Third Symposium on Radiation Chemistry, Tihany, Hungary, B / 38 (1971)).

The processes for producing polymer-wood combinations generally consist of the three process steps of wood preparation (drying, shaping), impregnation with the monomer and polymerization. If the moisture content of the wood is low (3.5 ... 4.5 #), it can be used directly for impregnation

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Otherwise, drying in air, in an oven or under vacuum conditions is required. Treatment of the wood with the monomers is first carried out at reduced pressure (10 × 30 mmHg) and then at elevated pressure (6 × 10 × 10 -4) During the vacuum treatment takes about 30 minutes, the impregnation under pressure can take several hours.Most often under nitrogen (possibly also argon) worked, since oxygen is known to be a strong polymerization inhibitor.The polymerization takes place under the action τοη gamma radiation The higher the radiation intensity, the faster the process, but since heat is released during polymerization and the temperature in the wood must not exceed a certain level to avoid sohing in the wood, the process must not be carried out too quickly.

Object of the invention

The aim of the invention is the simple production of polymer-wood combinations.

Explanation of the essence of the invention

The object of the invention is to specify a simple and rapid process for the production of polymer-wood combinations.

The inventive method for the production of polymer-wood combinations is that dry wood soaked with the solution of a polymer and then the solvent by known methods, for example by heating, vacuum evaporation or simple evaporation in the air, removed from the wood becomes. It has surprisingly been found that polymers brought into solution, for. As polyethylene, polystyrene, polymethacrylate u. a. well absorbed by dry wood. When the removal of the solvent (xylene, toluene, dioxorethane, trichlorethylene, etc.) has formed a polymer film,

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which makes the wood hydrophobic and well preserved against external influences *

If polymers are used which are crosslinkable under the influence of ionizing radiation, then the wood, after impregnation with the polymer solution and removal of the solvent, can be treated with ionizing radiation, most preferably with gamma radiation The dose depends above all on the polymer used it is usually 10 kGy and should not exceed 50 kGy. Crosslinking of the polymer improves the properties of the polymer / wood combinations, in particular with regard to hardness and / or abrasion resistance.

The goal parts of the invention are that the production of polymer-wood combinations is simplified; for example, the duration of the action of the polymer solution during impregnation of the wood is only minutes to a few hours. In addition, neither a vacuum nor increased pressure is required.

embodiment

1. Fittings of dried wood (Feuohtegehalt ca 5 #) are soaked for 10 minutes with a 1.5 # solution of polyethylene in xylene · Then the xylene is driven off by heating.

Investigations show that the polyethylene has spread evenly over the entire inner and outer surface of the wood. The polymer-wood combination is hydrophobic and easy to polish.

2. Some of the first examples of polymer-wood fittings obtained are treated with gamma radiation from a cobalt-60 source. In total, a dose of about 10 kGy is applied. Due to the cross-linking of the polyethylene, the hardness and abrasion resistance of these molded pieces are, when the hydrophobicity and polishing barksite are preserved, compared to untreated wood

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almost 100 % increased.

3 · fittings Mooreiche (moisture content about 45 are "dried at 110 ⁰ C and then a 9 # solution of polystyrene in dichloroethane for 15 minutes" 4 Stunden treated. The solvent is evaporated by heating. The obtained polymer timber Combinations are hydrophobic and improved in the essential performance properties (hardness, abrasion resistance)

Claims (6)

238019 Erfindungsanspruoh • J process for the production of polymer-wood combinations, characterized in that dry wood is impregnated with the solution of a polymer in a suitable solvent and then the solvent is removed from the wood by known methods. 2. The method according to item 1, characterized in that Ternetzbare polymers are used and the wood is treated after removal of the solvent with ionizing radiation. 3. The method according to item 1 and 2, characterized in that the dose is a maximum of 50 kGy. 4. The method according to item 1, characterized in that such polymers as polyethylene, polystyrene, polymethacrylate are used · 5. The method according to item 1, characterized in that as solvent xylene, toluene, dichloroethane, trichlorethylene u. a. to be used * 6. The method according to item 1, characterized in that the concentration of the polymer in the solvent is not more than 10 #.