SU1096105A1 - Method of modifying wood - Google Patents

Abstract

A METHOD FOR MODIFYING WOOD, which includes its impregnation in acetic anhydride at elevated temperature, extraction with methylene chloride and drying, characterized in that, in order to improve the performance and dimensional stability of acetylated wood, impregnation is carried out 120-160 min at 107-110 & C in a mixture of acetic anhydride and toluene, taken in volume ratios of 3-15: 100, moreover, wood is taken in an amount of 0.05-0.1 ob.h from the volume of the mixture of acetic anhydride and toluene, and extraction with methylene chloride is carried out 60-100 m n.

Description

Yu

with:

with about:

The invention relates to methods for producing modified wood and can be used in the woodworking industry.

There is a method of acetylation of wood, which includes treating it with acetic anhydride, subsequent evacuation and extraction with gaseous ethylene oxide at 100-120 ° C G11.

The closest to the proposed technical essence and the achieved result is a method of modifying wood, including its impregnation in acetic anhydride at elevated temperature, extraction with methylene chloride and drying of G 2.

The disadvantages of the known methods are the length of the wood processing time and the relatively low dimensional stability of the acetylated wood.

The purpose of the invention is to increase the productivity of the method and the form stability of acetylated wood.

This goal is achieved by the fact that according to the wood modification method, the impregnation is carried out for 120-160 minutes at LOT-IIO C in a mixture of acetic anhydride and toluene, taken in volume ratios of 3-15: 100 and the wood is taken in 0.05-0 , 1 ob.ch. by volume of the mixture of acetic anhydride and toluene, and extraction with methylene chloride is carried out for 60-100 minutes.

The introduction of toluene into the wood acetylation mixture is caused by the following: it combines well with acetic anhydride, its boiling point is 1PO, which is an acceptable temperature during the acetylation process D known methods after the treatment temperature, ° C 120 Treatment time, min. 60 Duration of extraction , min140-200 Volume ratio of treated wood and acetylation mixture 1 | .-ll. .-. JU ... - --zi-j. -.i ..- J.-J-, a-l i ir

sorption equilibrium is reached for some time of acetylation, and the process of diffusion of acetic anhydride inside the cell is completed, the use of toluene in the mixture

for acetylation contributes to the mixing of this sorption equilibrium, thereby providing the best conditions for a more complete acetylation reaction; during the course of the acetylation reaction, which is exacerbated by acetic acid in the volume of wood, forms an azeotropic mixture with a toluene mixture in a mass ratio of 37-73, unlike acetic acid

5) the boiling point of the formation of a ceio azeotropic mixture is significantly lower and is 107 ° C. Varying the ratio of the volume parts of the processing wood and

Q volume of the acetylating mixture, it is possible to achieve the case in which most of the acetic anhydride will react with the components of the wood with a high degree of substitution.

Examples 1-5. Billets of old vasins are placed in a g plant equipped with a reflux condenser with a direct cooler, as well as a dropping funnel, and a thermofluid at 107–110 ° C for 120–160 min in a mixture of acetic anhydride and toluene, taken in volumetric ratios 3: 15-100, and the wood take in the amount of 0.050, 1 ob.h. by volume of a mixture of acetic anhydride and toluene followed by

5 extraction with methylene chloride for 60-100 minutes During heat treatment, the toluene consumption from the dropping funnel is chosen equal to the amount of the azeotrope distilled.

Modes of acetylation are given in Table. 1, and in table. 2 - dependence of the shape stability of acetylated wood on the processing conditions.

Table 1 9710/107 110 117 240160145 120 190 12010070 60 85 0.20.1 0.075U, 05 0.03 g :: -. -.i-a .. d- -J- -seg with: g- Table

2.3

3.4

2.0

3.1

2.5 1.7 1.2

2.1

Thus, the foregoing method allows to obtain a material whose dimensional stability in comparison with the prototype is much higher, while it is more productive,

as it allows to reduce the processing time during acetylation of wood by 2-2.5 times.

Claims (1)

METHOD FOR MODIFICATION OF WOOD, including its impregnation in an environment of acetic anhydride at elevated temperature, extraction with methylene chloride and drying, characterized in that, in order to increase the productivity and form stability of acetylated wood, the impregnation is carried out for 120-160 min at 107-110 ° С in a mixture acetic anhydride and Toluene, taken in volume ratios of 3-15: 100, with wood being taken in an amount of 0.05-0.1 vol.h of the volume of the mixture of acetic anhydride and toluene, and extraction with methylene chloride was carried out for 60-100 minutes.