EA007980B1 - Ecologically-clean water-resistant wood-mineral-polymer composite - Google Patents

Abstract

The invention relates to compositions, preparation and treatment of wood-mineral-polymer composites, as well as to the production of construction materials and articles based thereon and it can be further used in woodworking industry, furniture-manufacturing industry, building and other industries.The invention is characterized in that the ecologically clean water-resistant wood-mineral-polymer composite, comprising dispersed wood, a mineral agent, thermo-plastic or elastomer binder, as well as one or several additives such as dispersed wastes of agricultural products wastes, crushed waste rubber, a dye, a water-repellant dressing, and further comprising a void filler (highly-dispersed sulfur), reinforcing member (metal or polymer gauze, fabric) or a cladding material (veneer sheet, paper, wall paper, film).The inventive result provides high water resistance, enhanced deformation and strength properties, better aesthetic and consumer qualities, ecological cleanness, as well as a substantial expansion of use of materials and articles manufactured therefrom.

Description

The invention relates to the field of formulations, preparation and processing of wood-mineral-polymer compositions (DMPK), as well as to obtain structural materials based on them. It allows you to skillfully dispose of waste wood processing, waste production of plant agricultural products, some highly dispersed mineral substances, as a result of reinforcement of DMPK provides a significant increase in their deformation and strength properties, expands their field of application and can be used in woodworking, furniture, construction, engineering and other industries, in particular, in the automotive and car building, in the production of furniture, packaging, decorative construction materials for facing administrative and residential premises, window and door blocks, heat-insulating plates, roofing tiles, floors, decoration tiles, platbands, window sills, handrails, baseboards, toys, formwork, linoleum.

Waste wood processing (flour, sawdust, shavings, crushed bark) are widely used as the main filler in the production of chipboard. The availability and cheapness of raw materials, the relative simplicity of the technological design of the processes for producing chipboard based on dispersed wood and phenol-formaldehyde and other thermosetting resins, a satisfactory level of their deformation-strength properties, the possibility of various modifications of their composition predetermined the creation of the enormous scale of chipboard production worldwide.

The technical progress of this industry is inextricably linked with the improvement of the composition (recipes) of the original compositions. Analysis of the scientific and technical (mainly patent) literature on this issue allows all the developed compositions to be conventionally attributed to four generations. The first generation of DMPA can be attributed to numerous compositions that include dispersed wood and thermosetting binder — phenol-formaldehyde, urea-formaldehyde, urea-phosphate, urea-phosphate, ligno-sulfonate-bichromate, formaldehyde-phosphate or siloxanethyl silicate. Pat RF 1728269 from 10.08.89; CO8 L 97/02; B.I. No. 1, 1992; 2. Pat. RF 1742292 from 09/08/89; CO8 L 97/02; B.I. No. 23, 1992; 3. Pat. Of the Russian Federation 2026324 from 01.30.91; 6 CO8 L 97/02; B.I. No. 1, 1995; 4. Pat. RF 2028338 from 04/25/90; 6 CO8 L 97/02; B.I. No. 4, 1995, p. 141]. Compositions of this type are multicomponent and contain dispersed wood (40-90 wt.%), Agricultural products processing wastes (for example, husks of rice, sunflower or millet grains), the aforementioned binder, and various functional and technological additives. For example, the composition for the manufacture of chipboard for a patent [5. Pat RF 2031915 from 11/19/90; 6 CO8 L 97/02; B.I. No. 9, 1995, p. 186] includes wood chips, particles of crushed stems of annual cereal plants (up to 70 wt.%), Urea-formaldehyde resin (5-13 wt.%), Aluminum-chromophosphate binder (3-9 wt.%), Carbamide (0.5-2.5 wt.%), Water (9-17 wt.%). Improved compositions of this type additionally contain silicone compounds, paraffins [6. Pat RF 2100391 from 04/05/95; 6 C08 L 97/02; B.I. No. 36, 1997], surfactants [7. Pat RF 2036943 from 04/01/94; 6 CO8 L 97/02; B.I. No. 16, 1995].

A common drawback of such compositions is their high toxicity, low water resistance, high flammability, low deformation and strength properties (in particular, high fragility).

When using such compositions in the process of manufacturing products and in the process of long-term operation of the latter, the release of free formaldehyde (carcinogen, nerve agent poison, its MPC = 0.01 mg / m ³ ), phenol (nervous system irritant, allergen) and other physiologically active harmful substances occurs. for human health substances (volatile acids, etc.). The rate of release of these pesticides with increasing temperature increases dramatically. At 100 ° C, the content of formaldehyde and phenol in DMPA and in their environment can be tens of times higher than the MPC of these substances. All this dramatically reduces the environmental safety of the use of materials of this type.

In recent years, the problems of the environmental safety of the production of particleboard and products based on them have become more significant for the world community than their technological and economic advantages. Due to the increasing number of chemically stimulated allergic and oncological diseases, the world community recommends to completely stop the use of phenol-formaldehyde resins and their analogues as binders in particleboard. However, despite numerous bans, the production and use of particleboard with phenol-formaldehyde binders continues in both Russia and other countries.

Awareness of this problem by producers and consumers has contributed to the expansion of research and development aimed at creating chipboard with improved environmental properties.

The quest to reduce toxicity and improve the properties of DMPK in the framework of the above classic basic formulations led to the creation of a second generation DMPK, from which phenol-formaldehyde and urea-formaldehyde binders were excluded.

Instead of phenol-formaldehyde and urea-formaldehyde binders, the use of inorganic binders (quicklime) was proposed as part of a particle board [8. Application for patent. RF 93011579/33 dated March 4, 1993; 6 C04 B 28/10; BI No. 14, 1995, C. 68], gypsum Ca8O ₄ -2H ₂ O, phosphogypsum [9. Application for RF patent 92009052/33 from 11/30/92; 6 С04 В 28/14; BI No. 5, 1995, P. 43], portland cement (30-55 wt.%) [10. Pat. RF 2026842 from 03.16.92; 6 C08 04B 28/00; B.I. № 2, 1995, P.140; 11. RF. Pat. RF 2022986 from 06.26.91 ; five

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C08 L 97/02; B.I. No. 21, 1994], alumochromophosphate, lignin sulfonate bichromate [12. Pat RF 2001065 of February 24, 1992; 5 C08 L 97/02; B.I. No. 37-38, 1993] and other mineral-organic resins [13. Pat RF 2010822 of 09/30/92; 5 C08 L 97/02; B.I. No. 7, 1994; 14. Pat. Of the Russian Federation 2017769 from 02.12.91; 5 C08 L 97/02; B.I. No. 15, 1994; 15. Pat. RF 2001065 of February 24, 1992; 5 C08 L 97/02; B.I. No. 37-38, 1993; 16. AS USSR 887602 from 1980; C08 L 97/02]).

For example, wood-Portland cement composition [10. Pat RF 2026842 from 03/16/92; 6 C08 04B 28/00; B.I. No. 2, 1995, p. 140] contains 25-50 wt.% Wood chips, 30-55 wt.% Of portland cement, 3-6 wt.% Ligninosulphonates, 5-10 wt.% Skin waste. The plates made from these compositions have a flexural strength of 1.4-1.8 MPa, a flexural modulus of 450-500 MPa, and a thermal conductivity at 20 ° С of 0.045-0.05 W / mrad. and water absorption 30-33 wt.%.

The use of the above-mentioned inorganic and mineral-organic resins as binders in the composition of wood-mineral compositions made it possible to obtain environmentally friendly plates and shaped articles that do not emit harmful substances.

However, as in the case of wood-phenol-formaldehyde or wood-urea-formaldehyde composites, wood-mineral composites in general are characterized by low water resistance, low deformation and strength properties and low frost resistance.

In order to eliminate these shortcomings in the late eighties of the last century, the third generation of particleboard was developed, in which asphaltite (25-50 wt.%) Was used as a binder in combination with lignin sulfonate (2-20 wt.%) [17. Pat RF 1778124 from 01/08/91; C08 L 97/02; B.I. No. 44, 1992], tall pitch (10-50 wt.%) [18. Pat RF 2004557 of 03/05/91; 5 C08 L 97/02; B.I. No. 45-46, 1993], polyacrylic acid with a molecular weight of 40-70 thousand g / mol (5-20 wt.%) [2. Pat RF 1742292 from 09/08/89; C08 L 97/02; B.I. No. 23, 1992], waste suspension of polyvinyl chloride (10-25 wt.%) [19. Pat RF 2059672 from 07.28.99; 6 C08 L 97/02; B.I. No. 13, 1996; 20. Pat. RF 2005752 from 07.15.92; 5 C08 L 97/02; B.I. No. 1, 1994], polymethyl methacrylate, polymethyl acrylate, copolymers of ethylene with acrylic acid (sivylene) [2. Pat RF 1742292 from 09/08/89; C08 L 97/02; B.I. No. 23, 1992]. It turned out, however, that all such composites also have low water resistance and low deformation-strength properties. Polyvinyl chloride deserves separate consideration. During the operation of products from wood plastics, including polyvinyl chloride, hydrogen chloride is released as a result of thermal, mechanical and photo-induced effects. Therefore, composites based on dispersed wood and polyvinyl chloride binder [20. Pat RF 2005752 from 07.15.92; 5 CO8 L 97/02; B.I. No. 1, 1994; 21. Pat. RF 2059672 from 07.28.99; 6 C08 L 97/02; B.I. No. 13, 1996] are also not environmentally friendly.

In the early nineties, the fourth generation of chipboard and environmentally friendly highly filled wood-mineral-polymer compositions were developed, including thermoplastic binder (polyethylene - PE, polypropylene - 1111, copolymer of ethylene and propylene - BOT, polystyrene PS, natural and synthetic rubbers) and more than 50 wt.% wood and mineral fillers [21. Savitsky A.S. Express information. - Plywood and wood-based panels. 1991. No. 12. С.2-17; 22. Application for Pat. Of the Russian Federation 92005207/33 from 10.11.92; 6 C04 B 30/02; B.I. No. 5, 1995, p. 43; 23. Application for Pat. RF 92005208/03 from 10.11.92; 6 C08 B 38/00; B.I. No. 5, 1995, p. 45; 24. Pat. RF 2005752 from 07.15.92; 5 C08 L 97/02; B.I. No. 1, 1994; 25. Pat. RF 2016022 from 01/31/92; 5 C08 L 97/02; B.I. No. 13, 1994; 26. Pat. RF 2,026,182 dated February 27, 1992; 6 B29 B 9/08; B.I. No. 1, 1995, p. 56; 27. Pat. RF 2056446 from 10.22.91; 6 C08 L 97/02; B.I. No. 8, 1996; 28. Pat. RF 2074208 from 07.21.93; 6 C08 L 97/02; B.I. No. 6, 1997; 29. Pat. RF 2081135 dated July 12, 1995; 6 C08 L 97/02; B.I. No. 16, 1997; 31.Pat. RF 2096432 from 10.10.94; 6 C08 L 97/02; B.I. No. 32, 1997; 32. Pat. RF 2125070 from 01/22/97; 6 C08 L 97/02; B.I. No. 2, 1992; 38. Pat. Of the Russian Federation 2132347 from 10/17/97; 6 C08 L 97/02; B.I. No. 18, 1999; 33. Pat. RF 2133255 from 10.17.97; 6 C08 L 97/02; B.I. No. 20, 1999].

The simplest composition used in the preparation of truly environmentally friendly chipboard contains 70-90% by weight of sawdust as a filler, and 10-30% by weight of primary PE powder as a polymeric binder [25. Pat RF 2016022 from 01/31/92; 5 C08 L 97/02; B.I. No. 13, 1994] or 20 wt.% Crushed secondary PE [21. Savitsky A.S. Express information. - Plywood and wood-based panels. 1991. No. 12. C.2-17]. The main disadvantages of such simple compositions are the relatively low level of physical and mechanical properties and the relatively low resistance of the materials obtained from them.

DMPK of any composition should be considered as a 3-component mixture consisting, firstly, of solid filler particles (plant waste and minerals) - up to 60% by volume, secondly, of thermoplastic material (various polymers and plasticizers) - up to 25 vol.%, and, thirdly, from voids, both initially in the filler particles, and voids acquired in the process of thermobaric molding of the product - up to 15 vol.%.

The decrease in the level of deformation and strength properties and water resistance of wood-mineral-polymer composite materials containing 10–20 wt.% Polyolefin binder is mainly due to the lack of affinity between the polymer binder and components of wood-mineral fillers and the presence in chipboard and other products of considerable size (up to 15 vol.%) free volume.

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In order to increase the deformation-strength properties of products from wood-polymer compositions, imparting new useful properties to them and expanding the areas of their application in DMPC, it was proposed to introduce functional organic and / or inorganic dispersed co-fillers [34. The USSR AS 495213, 1975; B 29 1 5/00; 35. Pat. U.S. 3,888,810, 1975; C 08 6 45/18; 36. Pat. U.S. 4,746,688, 1988; C 08 K 3/34; 37.3 Japanese Appeal No. 63139946, 1988; C 08 L 101/00]. For example, compositions that include dispersed wood (sawdust, flour of coniferous and deciduous trees) and PE binder, additionally contain the following concretes: reinforcing chopped fibrous plant materials (flax, hemp, stalks of cereals) [34. The USSR AS 495213, 1975; B 29 1 5/00; 35. Pat. U.S. 3,888,810, 1975; C 08 6 45/18], a mixture of a cross-linked elastomer (dispersed rubber) with talc or barite [36. Pat U.S. 4,746,688, 1988; C 08 K 3/34], magnesium oxide [37. Japanese Application No. 63139946, 1988; C 08 L 101/00]. Among the compositions of this type there is a composition that includes the following components: vegetable dispersed lignocellulosic filler (5-65 wt.% Dispersed wood in the form of flour or sawdust); vegetable fibrous filler (15-110 wt.% chopped hemp, nettle, flax or jute); thermoplastic binder (PE, PP, BOT, ABC copolymers or polyamide 6 (nylon)) (100 parts by weight) and inorganic co-filler (10-40 wt.% talc) [38. Pat EPO No. 0319589, 1990; C 08 L 101/00]. Products from such compositions have increased strength during impact, stretching and bending. The disadvantage of such compositions is the low content of wood-based filler (natural polymer) in them, which, with a relatively low content of PE binder, leads to a significant decrease in water resistance and deformation-strength properties of the products obtained from them. To increase the strength characteristics of products from DMPK, DMPKs include adsorption, mechanically or chemically modified particles of the solid components of the compositions [39. A.S. USSR 1722835, 1992; B 27 N 3/02; 40. Application of France No. 2602513, 1988; C 08 L 23/04; 41. The patent of the Russian Federation 1826939, 1993; B 27 N 3/02; 42. A.S.SSSR 1692841.1991; B 27 N 3/02; 43. Pat. U.S. 4,559,376, 1985; C 08 b '/ 2; 44. A.S. USSR 1062019, 1983; In 29 1 5/00]. So, one of the DMPK [40. Application of France No. 2602513, 1988; C 08 L 23/04], along with a polyethylene binder, contains in its composition particles of wood-vegetable filler, modified by polymer from a solution. The main disadvantage of such compositions is the complex technological design of their production.

Closest to the claimed invention to the technical essence and the achieved result is environmentally friendly waterproof wood-mineral-polymer composition, including dispersed wood; mineral additive (inorganic co-filler); thermoplastic polymer (polyethylene, polypropylene, polystyrene) or elastomeric binder, as well as one or more other additives, such as dispersed waste from agricultural products, dye, fire retardant, crushed rubber (regenerate), water-repellent finishing agent, polymerization initiator, inorganic pigment and fragrant substance natural origin in the following ratio, wt.% [45. Application for Pat. RF 2000110310 of 04/25/2000; IPC 7 C

08 97/02]:

Inorganic (mineral) additive (honey filler) 0.5-40.0

Polymer binder 5-30

Dispersed waste from the processing of agricultural products 0.1-10.0 Crushed waste rubber (regenerate) 1-5

Dye 0.05-0.5

Fire retardant 3.0-30.0

Polymerization initiator 0.1-0.5

Water repellent finish 0.05-3.0

Inorganic pigment 0.1-5.0

Aromatic substance of natural origin 0.01-1.0

Dispersed wood Else

We consider this invention as a prototype. The main disadvantage of the prototype solution is the relatively low deformation-strength properties of the products obtained from these compositions, even with their optimal composition.

The present invention is to improve the water resistance, increase the deformation-strength properties of the DMPA and the resulting products, improving the aesthetic and increasing consumer properties of composites and products from them with a low content of binder in them.

The problem is solved in that the environmentally friendly water-resistant wood-mineral polymer composition (hereinafter referred to as composition), including dispersed wood, mineral additive (0.5-40 wt.%), Thermoplastic polymer or elastomeric binder (10-40 wt.%), And also one or more other additives, such as dispersed waste from the processing of agricultural products (0.1-10 wt.%), crushed waste rubber (1.0-10.0 wt.%), dye (0.01-1.0 wt.%), water-repellent finish (0.05-3.0 wt.%), according to the invention additionally contains a filling void carrier, reinforcing component or facing material in the following ratio, wt.%:

Filler of voids 1,0-5,0

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Reinforcing component Facing material Dispersed wood

3.0-30.0

2.0-5.0

The rest is up to 100 wt.%

All components of this composition, listed in the claims to the distinctive part, are used in the same proportions and for the same purpose as in the prototype. Examples of formulations of wood-mineral-polymer compositions for the manufacture of various products and physical and mechanical characteristics of the materials obtained from them are given in table. 1, 2. These examples demonstrate, but do not exhaust all possible formulations, compositions developed. The characteristics of the properties described in the table, characterized by wood-mineral-polymer composites, confirm the possibility of using them for the manufacture of structural materials of various purposes.

From tab. 2 shows that the compositions usually contain a significant free volume, filled with air. The presence of free volume in the products reduces their deformation-strength properties, water absorption and water resistance. To fill the free volume according to the present invention, the composition contains a low-melting core filler (claim 2). As a void aggregate, the composition according to the present invention contains highly dispersed sulfur (large tonnage oil and gas processing waste) (Claim 2). Sulfur melts at 110 ° C to form a low-viscous melt that fills pores that are inaccessible to a highly viscous polymer. The content of the voids in the composition vary in the range from 1.0 to 5.0 wt.%. In the presence of a polymeric binder in DMPK with reactive double bonds, sulfur contributes to their crosslinking and thereby provides an additional improvement in the strain-strength properties of the DMPC.

As a reinforcing component, the developed compositions contain a polyethylene brazed net, a polypropylene net, a raffia net, a nylon net, a glass cloth, a carbon cloth or a metal net made of anodized steel (claim 3). The content of the reinforcing component in the composition varies from 3.0 to 30.0 wt.%.

The reinforcing component in the composition and the products obtained from it are placed on one side or on both sides in subsurface layers (Claim 4). This provides the maximum possible in each case, hardening obtained from the composition of the product.

As a cladding material, the developed DMPK contains ash or oak veneer; colorless, colored or patterned paper; polyethylene terephthalate film (claim 5 in the claims). As well as reinforcing components, facing material contributes to the improvement of the deformation-strength properties of products. Therefore, the compositions may contain reinforcing components or facing material. In addition, the cladding material provides the product with DMPK a high aesthetic quality.

Acceptable for practical use of DMPK formulations are very diverse, since the developed composition may contain any possible combination of components mentioned in its description (claim 6 in the claims). As already noted, the examples given in the tables demonstrate, but do not exhaust, the formulations of the compositions and their properties.

Developed DMPK and products from them are prepared by known methods. The preparation of the simplest DMPC containing all the components mentioned (including chopped fibers and sulfur) involves dosing operations into the mixer (by mass or volume) and subsequent thorough mixing of the components. To increase the homogeneity of the resulting mixtures, it is necessary that the components of the DMPA have approximately the same particle size. Since this method of mixing does not exclude the enrichment of the lower layers with particles of higher density (sand, stone powder), the latter are first treated with oil and only then with highly dispersed sawdust, which, enveloping the high-density particle of the filler or co-filler, makes it less dense, and this interferes with stratification of DMPK. All DMPK can be divided into pressing and molding. Molding DMPK from pressing are characterized by a high (up to 35-50 wt.%) Content of thermoplastic and / or elastomeric binder.

The manufacture of products from the described formulations of the compositions produced by thermobaric molding of the product according to a given program in a heat-heated flat or figured mold at temperatures of 140-220 ° C under a pressure of 1.0-5.0 MPa for from 0.1 to 3.0 min / mm thickness of the finished product or heat-heated tunnel-conveyor rolls. In the industrial production of DMPK products, existing equipment for the production of chipboard (Zimpelkamp, SP-25, SP-35, Bison, Raut, Rauma-Repola lines, etc.) can be used. In the production of molded products from DMPK or linoleum, existing standard equipment can already be used.

In the manufacture of chipboard and other products by the method of thermobaric pressing the prepared composition is loaded into the mold. Before or after this, the reinforcing components and the facing material are placed in the mold so that the reinforcing components are placed

- 4 007980 were laid in the subsurface or in the surface layer of the composition, and the facing material was placed on one or both sides of its surface (see Fig. 1, 2).

The advantage of the products from the developed compositions is that they are distinguished by ecological purity, high water resistance, high frost resistance, biostability, low prime cost and adaptability. Due to their thermoplasticity, if necessary, they can be reformed after appropriate heat treatment in accordance with the specific requirements of the interior. In addition, waste and products from the developed environmentally friendly wood-mineral-polymer compositions can be recycled using thermobaric methods, which allows you to create an almost waste-free process.

Examples of formulations of wood-mineral-polymer compositions for the manufacture of various products and physico-mechanical characteristics of the materials obtained from them are given in table. 1, 2. We emphasize once again that these examples demonstrate, but do not exhaust all the possible formulations and compositions developed. As polymers for the preparation of the developed compositions were used:

high density polyethylene (HDPE) powdered unstabilized unpainted grade 20908-040 (GOST 16338-85);

ethylene copolymer with propylene powder;

dispersed to the required fractional composition of waste processing of PE or PP, reused products of dispersing plastic packaging, packaging, damaged plastic products, etc .;

ethylene-propylene-dicyclopentadiene rubber;

synthetic isoprene rubber SKI-3; suspension polyvinyl chloride (GOST 14332-78); polyvinyl emulsion chloride (GOST 14039-79); PVC microsuspension (SSCHST 14039-79);

waste PVC emulsion (TU 6-01-1179-79).

Fractionation of dispersed waterproof components of the developed compositions was performed by sieving dispersed material on a sieve analyzer with a wide range of sieves. The average equivalent particle diameter in fractions was evaluated by statistical processing of photographs of samples obtained using a MBS-10 microscope. The moisture content in the fillers and fillers was determined by a gravimetric method using an analytical balance, as well as by a derivatographic method on an Oppouhigar11-0 instrument made by MOM (Hungary).

The manufacture of plates for determining the deformation and strength properties of the developed compositions was produced using a laboratory hydraulic press. After loading the mixture of all DMPK components into the mold, it was heated to a predetermined temperature, which should be approximately 20-30 ° C above the melting point of the thermoplastic binder. In the case of polyethylene and polyvinyl chloride binder, DMPK was heated to 140-160 ° C. In all cases it is necessary to ensure complete melting of the thermoplastic binder. Usually this was achieved at temperatures of heating the mold 140-160 ° C. Due to the low thermal conductivity of the DMPC, the duration of the operation of its thermal heating to a predetermined temperature varies from 15 to 60 minutes. Metallic, mineral and carbonaceous fillers provide a significant reduction in the duration of this operation. After heating the composition to a predetermined temperature and melting the thermoplastic binder in the entire volume of the molded product, the composition is compressed at a pressure of from 1 to 5 MPa. The pressing pressure determines the density and deformation-strength properties of products. These characteristics typically increase with increasing product density. The formed heated product is held under pressure for 5-15 minutes, followed by cooling it under pressure to a temperature 30-50 ° C below the melting point of the thermoplastic binder. In the case of a polyethylene binder, the mold with the resulting product is cooled to a temperature below 100 ° C, after which the pressure in the mold is reduced to atmospheric, the product is removed from the mold and filled with a new portion of DMPC (see Fig. 3).

The conditions of thermobaric treatment of DMPK significantly affect the structure of the thermoplastic matrix. The structure of a crystallizable polymer is estimated by the degree of its crystallinity. This characteristic of the thermoplastic matrix was determined by X-ray structural analysis.

The density of the samples was evaluated by the method of gradient tubes and according to GOST 15139-69. The strength characteristics of the samples were determined according to GOST 4648-71 using a modified tensile testing machine Ιηκΐτοη with rectangular samples at a speed of movement of a loaded platform of 2 mm / min. The values given in table. 2 physicomechanical characteristics were obtained by averaging the results of tests of 5-10 samples.

Water absorption over a certain period of time (the kinetics of water absorption) was determined by the gravimetric method, and the change in the dimensions of the sample over time was carried out by precision direct measurement of the length, width and height of the samples.

Properties DMPK (tab. 2).

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The basic parameters of products from DMPK, mainly determining their deformation-strength properties, are the real density of DMPK - p ₀ and the content of voids in the DMPC - φ ₀ . The density of DMPC was determined empirically, the proportion of voids - from the relation (1) fo = pho * / (pho * + f1 * + f2 * + fz * + .... + F1 *) (1), where φ ₁ *, φ ₂ *, φ ₃ *, .... φ ₁ * - volume fractions of ingredients, φ ₀ * - the apparent volume fraction of voids, which was calculated from the relation (2) pho * = 1 - ro / po * (2), where p _о * and р _о - calculated and real density of DMPC, respectively. The calculated density of DMPC was found from the relation (3) po * = ("1 / p1 +" 2 / p2 + ... + "1 / p1) ^-1 (3), where p1, p ₂ ... p ₁ and αι .α ₂ ... α, - density and mass fractions of ingredients included in the DMPC.

The most informative data on the deformation-strength properties of products from DMPK were obtained as a result of testing samples (plates in the form of a parallelepiped about, 5 x 2.5 x 6, about cm ³ , with the distance between the supports L = 3.2 cm) for bending. Flexural strength was determined by the formula (4) δ ...... = 3РЬ / 2ЬЬ ² (4), where P is the breaking force applied to the middle of the sample, kg; B — distance between supports, cm; B and 11 are the width and thickness of the sample, cm, respectively.

Elongation at maximum deflection of the sample, ζ, at the time of destruction bizgib = (6ζ.1ι / 1 ²⁾ x 1oo% (5)

When a DMPK plate is reinforced under the surface mesh from two sides, the plate is destroyed in three stages, schematically shown in FIG. 1. At point 1 of the section of the bending curve o-1, the outer peripheral (distant from the point of application of the load P) layer is destroyed, the peripheral reinforcing mesh is destroyed at point 2, and finally, at the point 3 - the internal grid (closest to the place of load P) . With one-sided reinforcement, the bending curve is limited either by the o-1-2 section or, depending on where the bending force P is applied, by the o-2- section

3. Finally, the destruction of unreinforced DMPK is limited to only one section of the bending curve: o-1, o-2, or o-3.

The ratio between the strength limits at points 1, 2 and 3 with two-sided subsurface reinforcement with a polymer mesh (polypropylene raffia, nylon) looks approximately like σ *: σ **: σ *** = 6: 3: 1. At the same time, the destructive elongations at the same points are in inverse relationship - ε *: ε **: ε *** = 1: 2: 4. The modulus of elasticity in bending E _bending e was calculated by the formula (6)

_FROM E r _and b = ³ Pb / 4Schy ³ (6)

Unilateral subsurface reinforcement of DMPK, as expected, leads, depending on the test conditions (see diagram in Fig. 2), to an increase in strength and flexural modulus and a decrease in the "elasticity" (relative elongation at fracture) of the samples compared to non-reinforced DMPC (columns 1-6, Table 2, in the numerator - loading according to option B, in the denominator - according to option C). At the same time, it is clear that the introduction of highly dispersed sulfur in columns (columns 3, 4 and 6) on average increases its strength properties. This may indirectly argue in favor of the crosslinking of reactive bonds in sulfur, both in wood and in polyethylene. However, it is impossible to exclude the effect of sulfur on the deformation-strength properties of products from DMPK and as a usual filler, which forms a rigid glassy frame in the free space of DMPK.

A single (columns 7 and 8, Table 2) and two-sided (columns 9 and 1 °) surface reinforcement of high DMPK (7 and 8) and medium (9 and 1 °) density gives slightly higher strength properties than subsurface reinforcement with nets, however This is most likely due to the geometry of the specimen loaded with bending (Variant D, Fig. 2). The low rates of physical and mechanical properties in DMPK No. 8 (Table 2) are due to the extremely high content in the composition of this DMP stone crumb 56% (No. 8, Table 1).

The manifestation of sulfur as a vulcanizing agent can be seen on the example of DMPK, filled with rubber regenerated crushed to small particles, containing residual double reactive bonds in rubber and long-lived free radicals formed during mechanical destruction. "Classic" DMPK lower average density (columns 15-18), in which the main ingredients are finely dispersed sawdust, pine polyethylene, sufficiently resilient minutes _mfd = 1.6-2.1%; ε ^ = 5,4-7,8%) and strong (and 2oo = _mfd kgf / cm ^2, σ ^ = 33o kgf / cm ^2). The increase in the share of crumb rubber (columns 39 and 4o), as well as the introduction of graphite, a substance with a low friction coefficient (columns 41 and 42) in medium density DMPCs, increases their elasticity, while their strength decreases, especially during compression. Finally, high density DMPK (columns 31-34) provides a high stone powder content of 33 to 45 vol.%, Which can be used for flooring, characterized by high stiffness E = E _{mfd compression channel} to 195oo kgf / cm ^2, high strength at compression - up to 6 ° kgf / cm ² and low destructive elongations - 5-7%.

Water absorption of DMPK, as is known, is higher, the more hydrophilic ingredients in it (in this case, these are sawdust). The penetration of water into the volume of DMPC leads to no

- 6 007980 reversible change in the geometric dimensions of the samples. Given in Table. 2 data on the water absorption of DMPK samples placed entirely in water at room temperature and atmospheric pressure for 1, 10, and 100 hours depend on the geometry of the samples. These data provide some insight into the dynamics of water absorption and allow us to confidently assert that the equilibrium (limiting) water absorption is directly proportional to both the proportion of water-absorbing ingredients and the fraction of voids available for water penetration into the volume of DMPC. Therefore, the struggle to reduce the penetration of water into the “body” of DMPA is carried out in two directions: (1) - a decrease in the share of hydrophilic ingredients and (2) the cladding of hydrophilic ingredients with hydrophobic, in particular, polymers from a number of polyolefins and sulfur. Sulfur, however, did not produce the expected result: the two component DMPK No. 19-22 (Table 1, sulfur + hardwood aspen sawdust) in water disintegrated into its constituent components after being in it for a little over an hour. During the hour of stay in water, the weight gain reached 350% (an increase of 4.5 times), and the sample thickening reached 210% (an increase of 3.1 times) - table. 2. Improved characteristics showed DIPA No. 23-26 (Table 1, sulfur + pine pine sawdust) - and their water absorption was less and their decay time into its constituent components increased to 30 hours. It is characteristic that after drying these two component DMPCs keep the same volume and the same thickness that they have acquired during their stay in the water. Their mechanical strength in dried form is not sufficient to use them as structural products.

The water resistance of all other DMPK formulas developed, measured by equilibrium (limiting water absorption and size increase in the pressing direction, i.e., the thickness of the plate), is excellent (columns 19-26).

The combustibility of the developed DMPK containing more than 50 wt.% "Non-combustible" components can be considered low (columns 7, 8, 12, 28-42, 44-46), and in the case of DMP containing less than 10 wt.% "Non-combustible" components (columns 1-4, 6, 9-11, 19-26, 43) - high. The intermediate content of "non-combustible" components in the DMPC provides them with "satisfactory" flammability characteristics.

The characteristics of the properties of wood-mineral-polymer composites reinforced in Table 2, as already noted, confirm the possibility of using them as structural materials of various purposes.

From the description of the developed wood-mineral-polymer compositions in the recipe tables and from the results of studying the properties of materials prepared from them, it follows that the developed invention eliminates the toxicity of the material, expands the range of components of the compositions, gives special properties to some DMPKs, improves the deformation-strength characteristics and water resistance , to improve the aesthetic and improve the consumer quality of composites and products from them.

Claims (6)

CLAIM 1. An environmentally friendly waterproof wood-mineral-polymer composition (hereinafter the composition), including dispersed wood, a mineral additive (0.5-40 wt.%), A thermoplastic polymer or elastomeric binder (10-40 wt.%), As well as one or several other additives, such as dispersed waste from agricultural processing (0.1-10 wt.%), crushed waste rubber (1.0-10.0 wt.%), dye (0.01-1.0 wt. %), hydrophobizing sizing (0.05-3.0 wt.%), characterized in that it further comprises a void filler reinforcing compo ent or facing material in the following ratio, wt.%: Void Filler 1.0-5.0 Reinforcing component 3.0-30.0 Facing material 2.0-5.0 Dispersed wood The rest is up to 100 wt.% 2. The composition according to claim 1, characterized in that it contains highly dispersed sulfur as a filler of voids. 3. The composition according to PP.1, 2, characterized in that as the reinforcing component it contains a soldered polyethylene mesh in nodes, a raffia polypropylene mesh, a nylon mesh, fiberglass, carbon fabric, anodized steel metal mesh. 4. The composition according to claims 1, 3, characterized in that the reinforcing component is located in it on one side or on both sides in subsurface layers. 5. The composition according to claims 1 to 4, characterized in that it contains ash or oak veneer as a facing material; colorless, colored or drawings-colored paper; polyethylene terephthalate film. 6. The composition according to PP.2-5, characterized in that it contains any possible combination of components mentioned in PP.2-5.