SU1033320A1 - Method of producing modified wood - Google Patents

Abstract

A METHOD FOR MANUFACTURING MODIFIED WOOD by treating it with ammonia, removing it chemically. associated ammonia, characterized in that, in order to improve the quality of the modified wood, the treatment with ammonia is carried out in a vacuum of 2 hundred: diy — under a vacuum of (-0.50) - (- O, 75) kgf and . temperature 18-22 C during 24O-360 mic in the first stage and under vacuum (-0.10) - (- 0.50) kgf / cm and temperature 6Q-80 C for 120240 minutes in the second stage, and sealing is carried out also in vacuum in 2 stages - under vacuum (-0.25) - (- 0.35) kgf / cm and a temperature of 50-85 ° C for 180-240 minutes in the first stage and g under vacuum (-0.30) - (- 0.40) kgf / cm i and a temperature range of 60-8 O with during 240-300 Min at the second stage. F / J

Description

The invention relates to woodworking industry, in particular to methods for modifying boards and bars, and can be used to make a parquet floor covering, panels, and the like. A known method of producing compressed wood by modifying with ammonia, according to which the treatment of wood with ammonia and the removal of chemically unrelated ammonia is carried out in the field of high-frequency currents, and the treatment with ammonia is carried out for 10-240 minutes at 60-, and the removal of ammonia is 5- 60 minutes in the same temperature range 1. However, the known method requires additional complex equipment, which significantly increases the cost of the process. A known method of manufacturing modified wood by treating it with ammonia at an overpressure of 2-4 kgf / cm in an amount of 20-40% by weight of absolutely dry wood, removing chemically unrelated ammonia, followed by compaction. According to a known method, peeled veneer is treated with ammonia, which is then compacted by hot pressing 2. However, in the process of hot npecco boards and bars having a greater thickness than veneer, microcracks are formed as a result of material deformation. The formation of microcracks reduces the wear resistance of the material. In order to manufacture modified planks and bars without microcracks in a known manner, it is necessary to reduce the specific pressure during hot pressing, which leads to a decrease in the density of the material obtained to 650 kg / m, in addition to the treatment with ammonia at an initial humidity of 10% and excessive pressure. contribute to the destruction of wood cells, which leads to the appearance of spots on the surface of the finished material. The purpose of the invention is to improve the quality of the modified wood. The goal is achieved in that the treatment with ammonia is carried out in vacuum in 2 stages - under vacuum (-0.50) (-0.75) kgf / cm and a temperature of 1822 ° C for 240-360 minutes in the first stage and under vacuum (-0.10) - (-0.50) kgf / cm and temperature BO-C0 for 120-240 minutes in the second stage, and compaction is also carried out in vacuum in stage 2 - under vacuum (-0.25) (-0.35) kgf / cm and a temperature of 50-85 ° C for 180-240 min at the first strike, di and under vacuum (-0.30) - (-0.40) kgf / cm: and temperature 60-80s within 240-300 min in the second stage. Example. Autoclave is loaded with blanks of natural birch wood 40 mm thick, humidity 64%, evacuates them to (-0.75) kgf / cm and is kept under vacuum 0.75 kgf / cm 15 min. Then the autoclave is admitted ammonia gas, after which the blank blocks are formed in ammonia in two stages: in stage 1, 240 minutes under vacuum (-0, 6) kgf / cm and temperature, and in stage 2, they are held in vacuum 0, 5 kgf / cm and a temperature of 70 ° C. Further, chemically unbound ammonia is removed from the autoclave and at the same time chemical compaction is carried out with ammonia treated wood in two stages: at the 1st stage 180 minutes at a vacuum of 0.25 kgf / cm and a temperature of 7, at the 2nd stage 240 minutes at a vacuum of 0.40 kgf / cm and temperature. Bars are dried and cooled. After this treatment, the resulting material has a density of 835 kgf / cm, abrasion 25.2%, hardness 39.8 MPa, water absorption in 24 hours 43.5% and dimensional stability (depressing) 1.05% without microcracks and spots. In a similar way, wood samples are made at different modes. max treatment with ammonia and compaction / Impregnation conditions and test results of impregnated samples are presented. you are in table 1.

1. Evacuation, kgf / cm -0.75 -0.75 -0.75 1 .1. . Medium temperature, ° С

18

18

18

18

18

18 18 0.75 -0.75 -0.75 -0.75 -0.75

Duration of vacuum, 15 min

Vyderzhka under vacuum, kgf / cm -0.75

0.75 18 15

Temperature

18

Wednesday, C

Duration 15 min

Ammonia wood processing

Supply of gaseous ammonia, kg / m

48

52

Pressure (va-2 cuum), kgf / cm-in, 75

-0.75

Temperature, C 18 18

Duration, min 82

72

Vyrozhka zarOTOBfOK in the environment W in the autoclave 1-stage

Pressure (va-g kum), kgf / cm -0.5

-0,6 20

Temperature, C 18

Duration, min 360

300

Stage 2

Pressure (vacuum), kgf / cm-0.15

-0.10 80

Temperature, C 60

Duration, min 240

240

Removal of chemically unrelated ammonia and chemical compaction

Stage 1

Table continuation

15 15 15

15

15 15

-0.75 -0.75 -0.75 -0.75 -0.75

18 18 18

18 18

15 15 15 60

15

52 130

52

50

52

50

-0.75 2, 0-3, o

75 -0.75 -0.75 -0.75 18 18 18 18 18 40

78

82 360

70

95

75

0.75 -0.6 -0.6 -0.3

-0.85 1.00 22 18-22 20 16 25 45

240 240 180 420 1200

360

-0.25 -0.20 -0.5 -0.05 -0.6 80 70 70 50 100

180 180 120 300

120, 5.1. Pressure (vacuum) kgf / cm -0.25 -0.25 0.35 5.2. Temperature, C 50 65 5.3. Duration, min. 240 240 5.4. Pressure (Ba-, j. Kuum), kgf / cm-0.35 -0.30 -0.40

e.a day-45.0 44.2 39.4 47.1

ki%

Decompression

(neg. W)%) 1.54 1.22 1.25 1.43

Continuation of the table 85 180

20 150

-240

1612 5010

708 50 52130

8.10 8.00

8.05

738 670 876-940

28,8

29.5 36.7

34.4 38.4 37.4

60.2 63.80

57.9

1.05 1.64 19.8 18.34, 25 -0.25 -0.10 -0.5 0.00 7575409530 180 180 120 360 3120, 40 - -0.40 -0.20 -0.7 Without chemical compaction 90 3.1. Coloring (by section) Light brown under a nut 3.2. Appearance Uniform - One - One. Native. 3.3. Three-dimensional formation (from the surface)

For comparison, a portion of the samples was impregnated in a known manner. The conditions and results of the impregnation are also presented in the table.

When using the proposed method, the abrasion of the sample lowers the 1H by 1.5 times, the water content is also 1.5 times, and the compression decreases almost 15-18 times, which is very important when assessing quality

Prolong Table

material performance for the production of parquet and furniture.

Carrying out the treatment of wood with ammonia and chemical compaction of wood in vacuum in 2 stages allows to obtain a material with a final moisture content of up to 8%, inhalation in a day to 39.4% with a static hardness of up to 47.3 MLa without microcracks, distortions and spots. . Korichne-Gel- Light-Va wood is yellow on a solid spot of 4 and Homogeneous-Homogeneous-Neod-Neiod-Neodnony. native native-native native

Claims (1)

METHOD FOR PRODUCING MODIFIED WOOD by treating it with ammonia, removing chemically unbound ammonia followed by compaction, characterized in that, in order to improve the quality of the modified wood, ammonia is treated in a vacuum in 2 stages - under vacuum (-0.50) - ( -0.75) kgf cm and ^a temperature of 18-22 ^minutes C for 240-360 minutes in the first stage and at a vacuum (-0.10) - (- 0.50) kg / cm and a temperature of 60-80 ° C. during 120-240 min in the second stage, and the compaction is also carried out in vacuum in 2 stages - at a vacuum of (-0.25) - (-0.35) kgf / cm ^g and a temperature of 50-85 ° C for 180 -240 min in the first stage and ₂ under vacuum (-0.30) - (- 0.40) kgf / cm and a temperature of 60-80 ° C for 240300 min in the second stage. СО СО СО>