RU2288929C1 - Expoxy-woody composite - Google Patents

Abstract

FIELD: building industry and materials.

SUBSTANCE: invention relates to preparing epoxy-woody composition. The composition comprises the following content of components, mas. p. p.: epoxy-diane resin ED-20, 100; polyethylenepolyamine as an amine hardening agent, 10; plasticizing agent, 15; rubber crumbs as waste in rubber-technical manufacture, 125, and pone saw-dust as filling agents, 62.5. As a plasticizer agent the invention uses mother epoxy resin representing waste in manufacture of epoxy resins. Invention provides enhancing water-resisting properties and to obtain the composition preventing evolving free phenol from splint-slab plate and possessing high exploitation properties. Invention is used as a water-resistant cover for woody plates and splint-slab plates and for reconstruction of defected member sites of woody constructions.

EFFECT: improved and valuable technical properties of composition.

4 tbl, 2 dwg

Description

The invention is used in construction as a waterproof coating for wood boards, in the restoration of damaged sections of elements of wooden structures, and also as a slab material.

Plate material is made by flat pressing of filler particles mixed with a binder at a temperature of 18-20 ° C and a pressure of 3 MPa. To reduce the viscosity, the ED-20 epoxy resin is heated to 50-60 ° C, then a hardener and a plasticizer are introduced into it. The resulting binder is thoroughly mixed and a mixture of wood sawdust with crumb rubber is added to it. The prepared mass is placed in metal molds and pressed during the day. Then, to speed up the hardening process, the compositions are heat treated at a temperature of 80 ° C for 2 hours. To use the composition as a coating, the mixture prepared in the same way is laid on the surface to be protected, and pressing is carried out at the same technological parameters as in the preparation of the plate material. The scheme for producing an epoxy-wood composition is shown in Fig. 1.

The analogue was taken as an epoxy-wood composition for coating wood (for leveling surfaces) (patent RU 2028344, C1, 02/09/1995). Composition of the composition in parts by weight: 10-20 epoxy diane resin ED-20, 10-20 dibutyl phthalate as a plasticizer, 10-15 polyethylene polyamine (PEPA) as an amine hardener, 30-70 graphite and 30-70 talc as fillers .

The objective of the invention is to protect particleboard from exposure to water, preventing the release of free phenol, as well as replacing chipboard in structures.

This technical task is achieved by the fact that ED-20 grade epoxy resin (GOST 10587-84) was used as a binder, and pine filings were used as filler, crumb rubber wastes from the production of rubber products from the ARTI plant in Tambov, plasticizer - uterine epoxy resin (ITU-I grade B) - waste from the production of epoxy resins. Curing was performed using polyethylene polyamine (PEPA) (TU 2413-357-00203447-99) at room temperature and atmospheric pressure. Rubber crumb is obtained by crushing recycled rubber products (used car tires, tires, production defects (gaskets, gas masks, gaskets)). The particle size distribution of rubber crumb was determined as the residue on sieves of size, mm, in%: 2.5: 1.25: 0.63: 0.315: 0.14 = 50: 16: 24: 8: 2.

ITU-I (STP 6-21-700-1.24-93) is a technological industrial waste and is a solution of a mixture of resins and dehydrochlorination products in toluene-butanol or toluene isolated from the mother liquor from the production of epoxy resins: ED-20, E-40 , E-05k, E-23. The ITU-I Uterine Resin must comply with the requirements and standards specified in Table 1.

Table 1
Regulatory requirements for the physicochemical parameters of ITU-I No. p.p. Name of indicator Standards STP 6-21-700-1.24-93 Brand a Brand b one Appearance Homogeneous clear liquid 2 Mass fraction of non-volatile in-in,% 45 ... 50 No more than 50 3 The color of the solution on the iodometric scale, mg iodine is not darker 7 - four Mass fraction of epoxy groups,% 10 ... 15 4 ... 15 5 Mass fraction of chlorine ion,%, no more 0.0035 - 6 Mass fraction of total chlorine,% no more 0.3 - 7 Resin solution purity The filling must be clean, the presence of single impurities is allowed, not more than 10 pcs. per 1 sq. dm - 8 Conv. the viscosity of the resin solution according to the viscometer B3-246 with a dia. nozzle 4 mm 13 ... 15 No more than 100 9 pH of the aqueous extract 6 ... 7 -

The influence of the degree of filling and plasticization on the physicomechanical properties of the epoxy-wood composition was evaluated according to the results of short-term tests for compression, transverse bending, and water resistance at room temperature (20 ° C). The calculation of the composition was performed in parts by weight, where the total weight of the composition was taken as 100. The test results are presented in tables 2, 3 and figure 2.

The study of the mechanical and physical characteristics of the composite material depending on the amount of the introduced plasticizer ITU was carried out on a composition containing 50 parts by weight wood filler (pine sawdust) of the total weight of the mixture. With the introduction of a plasticizer, the viscosity of the binder decreases and the processing conditions of the composition improve.

At 15 parts by weight plasticizer material has the highest density (1) and bending strength (2) and compression (3), as well as the least water absorption (in 2 hours (4), in 24 hours (5)) and swelling in thickness (in 2 hours (6 ), in 24 hours (7)) (figure 2). A further increase in the amount of plasticizer leads to a deterioration in the mechanical and physical characteristics of the composition.

The effect of the degree of filling on the physicomechanical properties of the composition was evaluated at an ITU content of 15 parts by weight. on the composition containing pine filings and asbofriction waste as a filler (Table 2).

table 2
The effect of the amount of filler (sawdust + AFO) on the physicomechanical properties of the epoxy-wood composition Amount of filler,% of the total mass σ _mfd, MPa σ _squ , MPa Density, kg / m ³ Water absorption by weight,% Thickness swelling,% After 2 hours After 24 hours After 2 hours After 24 hours 60 2.68 11.32 740 9.92 21.83 0.26 1,58 65 0.89 5.36 614 16.72 69.6 1.12 4.72 70 0.42 2.98 535 35.77 120.79 1.21 4.13 80 0.24 1,67 460 75.8 131.73 3.68 5.13

The composition has the best performance when the amount of filler is 60 parts by weight, therefore, the optimal ratio of pine sawdust and crumb rubber for the invention is determined on the composition containing 60% of the filler (table 3).

Table 3
The effect of the ratio of fillers (pine sawdust and crumb rubber) on the physical and mechanical properties of the epoxy-wood composition The ratio of the mass of fillers σ _mfd, MPa σ _squ , MPa Density, kg / m ³ Water absorption by weight,% Thickness swelling,% After 2 hours After 24 hours After 2 hours After 24 hours 0.5 3.98 - 981 11.56 13.23 1.39 1.73 one 3.23 - 824 16.26 28.8 1.19 2.54 2.2 1.51 3.93 604 9.55 21.86 0.20 1,56 5 1,04 2.71 568 16.83 36.82 0.932 2,792

Studies have shown that the use of pine sawdust and crumb rubber as a filler in the epoxy composition can replace traditional fillers specially manufactured by the industry without compromising the performance properties of the material.

From the above data it is seen that the composition containing 15 parts by weight of the ITU plasticizer and 60 parts by weight of the filler with a ratio by weight of pine sawdust and crumb rubber of 1: 2 has the best set of physical and mechanical indicators.

Due to the fact that the invention is used as a coating for particleboard and in the restoration of damaged sections of elements of wooden structures, for optimal composition, adhesion to chipboards and wood, as well as the effect of water on the strength of the composition, were investigated. For wood chipboards coated with this composition, the drop in bending strength, swelling and water absorption after 24 hours of soaking were studied (Table 4)

Table 4
Physico-mechanical characteristics of the epoxy wood composition No. p / p Indicator Value one Destructive stress, MPa, with: - compression 7.30 - transverse bending 5.37 2 The elastic modulus in compression, MPa in the direction of pressing 56.9 in the direction of perpendicular pressing 120.7 3 Density, kg / m ³ 1000 ± 50 four Adhesion, MPa
to chipboard
to wood
1.77
4,58 5 Residual strength,%, after exposure to water for
- 2 hours
- 24 hours
- 168 hours
- 672 hours

one hundred
one hundred
83.6
76 6 Water absorption by weight,%, per
- 2 hours
- 24 hours
- 168 hours
- 672 hours
11.56
13.23
31.16
31.18 7 Thickness swelling,%. behind
- 2 hours
- 24 hours
- 168 hours
- 672 hours
1.39
1.73
2,36
4.45 8 The coefficient of linear thermal expansion α × 10, deg ^-1 3.13 9 Residual bending strength of particleboard with a coating thickness, mm, in 24 hours,%
2.9
3,7
4,5
6.0
65
68
65
73 10 The same for chipboard without coating,% 29.5 eleven Water absorption by weight of particleboard coated with a thickness, mm, in 24 hours,% 2.9 26.5 3,7 20.6 4,5 23.6 6.0 20.1 12 The same for chipboard without coating,% 65.8

Continuation of table 4. one 2 3 13 Thickness swelling of particleboard coated with a thickness, mm, in 24 hours,%
2.9
3,7
4,5
6.0
3,54
2.13
5.11
3.28 fourteen The same for chipboard without coating,% 21 fifteen Residual hardness, MPa, particleboard with a coating thickness, mm, in 24 hours,%
2.9
3,7
4,5
6.0
84.1
72.8
81.1
88.0

In the study of adhesion to particleboard, the destruction of the samples occurred along a chipboard, and to wood along an adhesive joint. As can be seen from table 4, the use of coatings for chipboard can significantly increase the water resistance of the material even with a minimum coating thickness compared to an uncoated chipboard. So, the residual strength of coated particleboards after 24 hours of soaking is 2 times higher, and water absorption and swelling are 3 and 5 times lower, respectively. The results show that the coating acts as a cage, limiting water access and plate swelling, which increases the structural bearing capacity. Another function of the coating is that it prevents the release of free phenol from particle board, which reduces its environmental hazard.

The authors propose the following composition of the epoxy-wood composition, parts by weight:

- epoxy resin ED-20 - 100;

- hardener PEPA - 10;

- plasticizer (uterine epoxy resin ITU-1) - 15;

- filler (pine sawdust) - 62.5;

- filler (rubber crumb) - 125.

The proposed epoxy wood composition has:

- good physical and technical characteristics;

- environmental safety;

- allows the use of industrial waste.

Claims (1)

An epoxy-wood composition for coating wood and chipboard, including ED-20 epoxy-diane resin, polyethylene polyamine as an amine hardener, fillers and a plasticizer, characterized in that the composition contains a mother epoxy resin - waste from the production of epoxy resins, as fillers - pine sawdust and crumb rubber - waste products of rubber products, with the following components, parts by weight: Epoxy Dianovy resin ED-20 one hundred Polyethylene polyamine 10 The above plasticizer fifteen Rubber crumb 125 Pine sawdust 62.5

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