Plastic from wood. A method of manufacturing products by pressing from wood plastic

A business idea for organizing small-scale production of products from various injection materials at home. Thanks to innovative technologies, today in the manufacture of plastic products, you can do without expensive thermoplastic automatic machines. Moreover, you can set up small-scale mini-production right on your desktop. This business idea can be viewed in two ways:

  1. As the main business of making finished products and molds by molding from: liquid:
    • plastic;
    • silicone;
    • polyurethane;
    • transparent resins and other materials.
  2. Mold making as an effective addition to other types of business in the field:

In the first and second cases, molding at home does not require large financial investments. You can start an injection molding business just now.

Manufacturing with liquid plastics

The manufacturing process is carried out using liquid plastics and silicone molds. Now there is an opportunity to produce plastic products in small batches at home:

  • souvenir products;
  • toys;
  • costume jewelry;
  • spare parts for auto tuning;
  • spare parts for various mechanical devices;
  • shoes;
  • dishes.

There are components for the manufacture of parts from thin-walled plastic, which can significantly expand the range of products and produce parts of any complexity. For example, mixing two components of the brand Axson FASTCAST F32 from the French manufacturer allows you to get a super-liquid plastic that flows out the smallest folds of the model's relief. In addition, it is harmless to children and odorless.

Preparation for production

To organize production, you will first need a sample model. On it, you first need to make a form from special silicone or polyurethane components. With experience and the quality of materials, you can learn how to remove molds from models at such a high level that you will even see fingerprints on the products (if necessary). That is, the copy will turn out at the level of identity, which cannot be distinguished with the naked eye. Complex compounds with any relief can be made into plastic products. If there is no ready-made model for a sample, but you need to make unique products, you can order it from the owners of the 3D printer. By the way, casting significantly exceeds the performance of 3D printing from plastic.

When your product is ready, you can design it with the help of related products that come with liquid plastics:

  • paints for artistic effects;
  • primers;
  • glue.

Naturally, in some cases, creativity is indispensable, and you will have to manually paint the products, which can affect performance. But creating every business is an undeniably creative process. After all, financial management is an art.

We make a product from liquid plastic

Do-it-yourself technology for creating an ideal shallow relief in a silicone mold. First you need to prepare all the components and materials. We need:

  1. Celikon Platinum.
  2. Liquid plastic Axson FASTCAST F18 (white color, has the consistency of water, odorless!).
  3. Scarlet dye for silicone.
  4. Polyurethane varnish.
  5. Scales.
  6. Syringe.
  7. File-buff.

We securely fix the sample model at the bottom of the formwork to form the shape, using neutral wax plasticine (to avoid silicone leakage). We paint the silicone, from which the finished form is obtained in a scarlet color, so that the quality of mixing the components of liquid, white to the color of plastic, is clearly visible on the form. Helpful hint: in order for the shape to be perfect, you should first coat the sample model with silicone using a wide brush. Thus, carefully fill in all the grooves of the relief with the compound. Only after that, fill the form completely. We fill the entire formwork with silicone. We leave it for 7-8 hours to fix the structure of the form. The hardest part is over.

Congratulations !!! Now you have a ready-made form for repeated production of duplicate items of the reference model. Make sure the mold is completely dry before starting casting to avoid the formation of bubbles. Then we very carefully mix the plastic components 1: 1 by weight (for this it is better to use a pharmacy or laboratory electronic scales). The setting time is 7 minutes, but it will take another 20 minutes to fully cure. This plastic is neutral to silicone and does not stick to it. However, after repeated use of the compound over time, it may be necessary to use an EaseRelease release lubricant. After the required time has elapsed, we take out the finished product, which is copied exactly according to the sample.

Polyurethane molds for construction

Molds for injection molding can be produced together with plastic products. The use of injection molds in construction is now very popular. Can produce compounds for manufacturing building materials... They are durable and do not require special release agents during manufacture. After all, concrete is absolutely neutral to polyurethane. For example, liquid polyurethane compounds allow the production of molds for pouring:

  • concrete decorative products (tiles, fences, etc.);
  • plaster elements of interior decoration (balusters, lepins, etc.);
  • liquid plastic when creating a variety of products (souvenirs, toys, figurines, etc.).

Silicone molds for pastry chef and soap making

The application of injection molding technology in the food industry is quite obvious. New innovative solutions in the field of chemistry today offer liquid: plastics, silicones, silicone masses, which meet all health care standards and have the appropriate certificates. Such safe components can be used to make molds for the food industry. For example, for production:

  • chocolate;
  • caramel;
  • isomalt;
  • ice;
  • mastics.

Also, compounds are in great demand among soap makers. They are always in need of new original shapes to create a salable souvenir made from soap. It is not at all difficult to find a customer who wants to manufacture their products with a unique shape.

Possibilities of a small business idea

This business idea makes it easy to create highly demanded products with your own hands. Finished works can be sold through the online store. It is also possible to provide services or sell off-the-shelf compounds to other manufacturers in other industries. Most importantly, with all these ample home business opportunities, the cost of the components is more than affordable. The range of components is wide and allows you to choose necessary materials to create shapes or fill them. All that is required is a sample model from which the form will be removed. This business idea is very attractive for a home business. It does not require a lot of costs, allows you to produce useful goods and carries away the creative process of production.

Unfortunately, all of us known and so widespread all over the world plastic contains substances harmful to human health. Moreover, petroleum products are used in its production. However, until recently, there was virtually no alternative to this cheap material. Of course, new construction materials appear constantly. These are plywood, chipboard and fiberboard. There are also novelties in the concrete industry, metallurgy, glass industry. Nevertheless, in terms of cost, and, therefore, availability, they are still far from plastic.

At the beginning of the new millennium, scientists managed to create a fundamentally new structural material, which in the coming decades can almost completely replace the usual plastic. it thermoplastic wood-polymer composite(DPKT or DPK), and in the common people - “ liquid tree". In its production, primary (secondary) raw materials PP, PE or PVC are used plus wood additives (wood flour, other vegetable fibers) and auxiliary additives. The effect exceeded all expectations. The newest material is not only environmentally friendly (the sulfur content is reduced by 90%), but also, combining the best properties of wood and plastic, has kept a relatively low cost.

According to experts, the annual growth in WPC sales in the world is about 20%. So what is this miracle that architects, designers and production workers have been waiting for so long? Let's try to figure it out.

Application and processing

Due to its properties, wood-polymer composite is excellently used in a wide variety of fields. The materials are distinguished by the uniformity and smoothness of the surface, plasticity, resistant to atmospheric and biological influences, and the service life even in harsh outdoor conditions reaches 50 years.

All this allows the use of WPC in the production of various architectural and building materials: skirting boards, lining, window sills, profiles, decorative elements, as well as fillers.

Ready-to-use products are made of WPC: laminate, floor coverings, furniture sheets, furniture, cable boxes, multi-chamber window profiles and even decking - a profile for the manufacture of berths and piers.

The physical and mechanical properties of the wood-polymer composite provide ample opportunities for its processing. Material does not lose its shape and strength, taking in up to 4% moisture. Lightweight, hollow things can be made from it. It is mounted both with nails and screws, and on special latches.

And also, WPC can be veneered with veneer, laminated with films and sheet plastics, painted with any paints and varnishes, and various decorative effects, adding pigments to the composition, etc.

Products obtained from WPC can be easily machined. They are easily sawn, drilled, cut, glued, welded to each other, bend (after preheating with a burner), and if soft wood flour or cellulose-containing waste is added to the material, this also gives the product increased plasticity.

Finally, the DPK, in addition to the aesthetics that gives it appearance, pleasant for the sense of smell, with a light woody scent.

Production technology

A number of components are used to make wood-polymer composite. First of all, it is, of course, shredded wood or cellulose-containing raw materials. That is, it can be not only wood, but also corn, rice, soybeans, straw, paper, sawdust, etc. The second main component of WPC is synthetic binders. These include: polyethylene, propylene PVC, etc. The rest of the components are additional additives, the composition of which varies depending on the purpose of the future product. The most common are: dyes, pigments, antioxidants, shock modifiers, light and heat stabilizers, flame retardants and antiseptics to protect against fire and decay, hydrophobic additives for moisture resistance, foaming agents to reduce the density of WPC.

Wood particle volume in the material can be from 30 to 70%, and their size is from 0.7 to 1.5 mm. Fine fractions are used in the production of finished profiles that do not require additional surface treatment. Mediums are suitable for painting or veneer finishing. Rough - for technical purposes.

The volume of synthetic binders x also varies and can be from 2 to 55%. It again depends on the purpose of the future product. As for additional additives, their volume in the material does not exceed 15%.

By the way, not so long ago, German developers managed to make "Liquid wood" of ideal quality... Fraunhofer Institute specialists created it from lignin. This material is obtained from wood. KDP called Arboform is absolutely non-toxic product. Moreover, if an ordinary wood-polymer composite can be recycled 3-4 times, then this one can be recycled up to 10 times. Why are we doing this? The fact is that in China, the WPC industry is growing like nowhere else in the world. And, if in Europe and the USA, the created materials undergo a series of tests, then in the Middle Kingdom they do not bother themselves with this and supply to the market, including the international one, a product of not the best quality.

Now about equipment for the production of WPC... Its standard composition includes: a twin-screw extruder, a forming die, a calibration and cooling table, a pulling device, a length-cutting device, a width division (if necessary) and a stacker. The entire line is compact and usually fully automated. The complete set of some models also includes: a mill (raw material grinder), an autoloader of raw materials, and a mixer.

The manufacturers of such lines and modules are mainly Chinese companies... The leaders among them are WPC, Zhangjiagang City Boxin Machinery and others. The quality of the equipment is of a decent level, especially since the main units for them are produced by European engineering plants.

22.05.2015


Plastics from wood press pulp (MDP) are produced by piezothermal treatment in molds, which provide parts of the required configuration.
Materials. For the manufacture of wood press masses different types lump veneer with a thickness of 0.5-1.8 mm, humidity up to 12%, waste wood laminated plastics, waste woodworking industries - shavings and sawdust are used. Wood waste should not contain inclusions of bark and rot, and chipboard waste is cut into lengths up to 120 mm for the possibility of loading them into the crusher.
Bakelite varnishes SBS-1 and LBS-3, phenol-formaldehyde resin SFZh-3011 and phenol alcohols B and C are used as binders in the manufacture of press masses. The concentration of bakelite varnish before impregnation should be 43-45%, and phenol-formaldehyde resin 28-35%. Mineral oil, oleic acid, dyes, aluminum powder, silvery graphite, copper powder, etc. are used as additives that improve the properties of MDP products.
Technological process for the production of TIR. The technological process of MDP production consists of the following operations: preparation of conditioned wood particles, preparation of a working solution of a binder, dosing and mixing of wood particles with a binder and a modifier, and drying of the mass.
Features of the technological process for the production of MDP are associated with the type of wood waste used, in the manufacture of press mass from sawdust (Fig. 106, a), they are sieved on a vibrating sieve with cells of 10x10 mm for large fraction and 2x2 mm - for small ones. Conditioned particles enter the dryer, where they are dried at 80-90 ° C to a moisture content of 3-8%. For drying, drum, belt and aerial dryers are used.
When lump veneer and chipboard wastes are used as raw materials, the technological process includes the operation of crushing wood in crushers (Fig. 106, b). To grind veneer, hammer crushers are used, for example, DKU-M. The veneer is crushed with knives and hammers mounted on the rotor of the machine. As they are crushed to the desired fraction, the particles are thrown out through a replaceable sieve and removed by pneumatic transport into the hopper. As a result, needle-shaped wood particles are formed with a length of 5-60 mm, a width of 0.5-5 mm, and a thickness of 0.3-2 mm. For crushing chipboard waste, a S-218 hammer crusher is used, crushing and sorting wood particles. The length of the particles after crushing is 12-36 mm, the width is 2-7 mm, and the thickness is 0.5-1.2 mm. Particle sizes depend on the purpose of the MPE.
Wood particles with a binder are mixed in worm-blade mixers, and sawdust - in mixer-runners. The rollers of the runners, when moving along the layer of sawdust, crush them into fibers, which further provides increased physical and mechanical properties of MDP products. Wood particles and binder are dosed by weight. They are mixed by feeding wood particles in portions of 80-100 kg. The temperature of the impregnating solution, depending on its viscosity, is 20-45 ° C. The duration of mixing in worm mixers depends on the type of particles. Sawdust, shavings and veneer particles are mixed within 10-30 minutes, and chipboard particles - 15-20 minutes. The amount of dry resin in MDP should be 25-30% and 12-15%, respectively). The duration of mixing in jogging mixers is 30-40 minutes, and the dry resin content in the press mass is 25-35%.
Modifiers are fed into the mixers after loading the impregnating solution in the following amount,%: oleic acid 0.8-1.5, urotropin 1-3, dyes 2-5, graphite 2.5-10, aluminum powder or copper powder 1.5- 3, mineral oil 10-20.
Drying of the press mass is carried out at 40-50 ° C for 30-60 minutes to a moisture content of 5-7%. For this, the same units are used as for drying raw wood particles.
Technological process for the production of TIRP products. For the manufacture of products, MDP can be used in the form of a free-flowing mass or in the form of a briquette obtained as a result of its preliminary compaction. The use of briquettes makes it possible to dose MDP more accurately, to reduce the volume of the loading chamber of the mold by 2-3 times, and to speed up the preheating process. Briquettes with a shape corresponding to the shape of the product (cylinders, parallelepipeds, etc.) are made in special briquetting presses or molds. Briquetting is carried out under a pressure of 20 MPa. At temperatures up to 25 ° C, the holding time under pressure is 1 min, at 50-60 ° C - 0.5 min.
To shorten the pressing cycle of MDP products, it is preheated. At 60-70 ° C, heating is carried out for 30-60 minutes, and at 140 ° C - up to 5 minutes. The most uniform heating is achieved in the HDTV field. Convective, induction and other types of heating are also used.
MDP products are made by hot pressing in hydraulic presses in closed-type steel molds. Pressing is carried out by direct and injection methods (Fig. 107). In direct compression, the pressure acts directly on the mass in the mold cavity. During injection molding, MDP flows under pressure from the loading cavity into the forming cavity; direct pressing is used in the manufacture of simple and large-sized products. Injection molding produces products with thin walls and a complex configuration. In the process of pressing, MDP is heated, softened, compacted, spreading in the cavity of the mold, and hardened.

The pressure during pressing of MDP, which has a weak fluidity, depends on the configuration of the parts and the pressing method. With direct pressing of parts with a straight contour, it is equal to 40-50 MPa. During injection molding of parts with a figured contour in the process of pressing the press mass into a mold, the pressure is 80-100 MPa, during pressing - 40-50 MPa.
The temperature of the mold during direct pressing is 145 ± 5 ° С. The pressing time depends on the wall thickness of the product. For products with a wall thickness of up to 10 mm, when the matrix and punch are heated, it is equal to 1 min / mm, when only the matrix is ​​heated, it is 1.5-2 min / mm, for products with a wall thickness of more than 10 mm, it is 0.5 and 1 min, respectively. /mm.
during injection molding, MDP is first compacted at a mold temperature of 120-125 ° C for 1-2 minutes. The mass is pressed into the mold at the same temperature. The end of this pressing period is determined by the moment the pressure starts to drop. Pressing is carried out at 145-165 ° C for 4 minutes. After the end of pressing, the products are cooled.
Products with a large contact surface with the mold are cooled with it to 40-60 ° C. Thin-walled products are cooled in a clamped state in special devices under a pressure of 0.2-0.3 MPa. Parts of a simple configuration and parts that are not dimensioned high demands, cooled in a free state.
Mechanical processing of MDF products consists mainly in the removal of flash and sprues. Additional machining in order to change the shape and size of parts is performed on metal-cutting machines.
In the production of 1 ton of MDP, the following is consumed: dry wood 1.8-2 m3, resin 600 kg, ethyl alcohol 340 l, steam 2 tons, electricity 70 kW * h.

You can cut the parts and hone each of them by hand, but this technique is very imperfect: it takes a lot of effort, and it is impossible to get two absolutely identical products. Therefore, in this material you will learn how to carry out plastic molding at home.

What we may need

We do not need any special tools or materials for our hand-made plastic molding. We can make a template model, a kind of matrix, from almost anything - from metal, cardboard or wood. But regardless of which option you choose, in any case it is necessary to soak it with a special solution before starting work. This is especially true for wood and paper, because they actively absorb moisture and to prevent this process, we need to fill the pores, preferably with liquid wax.

Silicone.

If we settled on this option, then we should buy it with the lowest viscosity - this will contribute to better streamlining of the part. Of course, the results will be more accurate. There is a great variety of its varieties on the modern market, and it makes no sense to compare them with each other: we have neither the time nor the opportunity for this. We can only say with confidence that a car sealant, preferably red, is ideal for coating. It will be much easier to pour plastic at home with it.

Determining the casting material

In all fairness, there are even more casting materials than silicone grades. Among them there are liquid plastic, and ordinary gypsum mixed with PVA glue, and even polyester resin. Substances for cold welding, low-melting metals, and so on are somewhat less popular. But in our case, we will be based on some other characteristics of the casting substances:

  • The term of their work.
  • Viscosity.

Regarding the first point, it denotes the time during which we can carry out manipulations with the material that has not yet hardened. Of course, if the manufacture of plastic products takes place in a factory, then two minutes will be more than enough. Well, we, who do this at home, need at least five minutes. And if it happened that suitable materials you could not get it, then they can be replaced with a simple epoxy resin. Where to find her? In car dealerships or in stores for fans of aeromodelling. It is also common in conventional hardware stores.

Making a split shape

This one is ideal for pouring plastic with your own hands, because you can pour unusual types of resins into it. A little trick of this technique is that at the preliminary stage, the entire surface of the model must be treated with silicone, and then, after the material has completely hardened, the matrix can be cut off. After that, we extract its "insides", which will be useful to us for further casting. In order for us to fit the shape, we need to apply a three-millimeter layer of sealant, after which we just wait for the material to harden - it usually takes two hours. In this case, it is desirable to apply it with a brush. When applying the first layer, we should try to fill all the irregularities or voids with the material, so that air bubbles do not subsequently form.

How the casting process works

First step.

We take a casting mold and clean it thoroughly - it must be dry and clean. All remnants of the material remaining after the preliminary procedures must be removed.

Second step.

If the need arises, we can slightly change the color of our composition: for this you just need to add one drop of paint to it, but in no case water (liquid plastics have a personal dislike for them).

Third step.

There is no need to degass our casting mix. This can be explained by the fact that the molding of plastics at home initially provides for the relative short duration of its "life". At the same time, in order to extract air bubbles from small-sized products, you just need to remove them with your own hands after pouring.

Fourth step.

Mix all the necessary components thoroughly and pour it into the template mold slowly, with a thin stream. This should be done until the mixture fills the entire volume and some more of the casting channel. And soon, when the degassing procedure takes place, the volume of this material will significantly decrease and become what we need.

And the last tip: in order for the quality of the model to be high, the template needs to be cooled gradually, slowly. So, follow all the instructions and you will succeed!

The production of ligno-carbohydrate wood plastics is a new industry. The problem of obtaining plastic materials from crushed wood particles without the addition of binders due to decomposition products of wood components has long occupied researchers. Many options for piezothermal processing of wood particles were proposed, which differed in modes, but essentially all these methods involved processing wood particles at high pressures and pressing temperatures, in hermetic molds. Subsequently, the plastics obtained in this way were called piezothermoplastics.

Currently, in our country, two methods have been proposed for obtaining piezothermoplastics:

1. The one-stage method, developed at the Belarusian Technological Institute, provides for grinding wood to a state close in particle size to wood flour, and pressing it in sealed molds at a pressure of 250-300 kg / cm 2 and a temperature of 190-200 ° C. subsequent cooling to 20 ° C without relieving pressure.

2. The two-stage method, developed at the Leningrad Forestry Academy, involves preliminary partial aqueous hydrolysis of wood particles in an autoclave followed by pressing the dried, partially hydrolyzed material in a mold in a hot press. Preliminary hydrolysis will reduce the pressing pressure for pressing materials made from wood of some hardwoods to 150 kg / cm 2 and the temperature of hot pressing to 160 ° C.

At the Department of Wood Science and Construction Business and in the problem laboratory of wood plastics of the Ural Forestry Institute under the guidance of prof. From 1962 to the present, V.N.Petri has been conducting versatile studies of new materials - ligno-carbohydrate wood plastics, obtained by using the reactivity of wood components (natural lignins and polysaccharides), without adding thermosetting resins or other binders to wood particles.

The authors of the new method, in contrast to the proponents of piezothermoplastics, believe that when obtaining plastics, wood should not be subjected to deep destruction, but only by mild effects during piezothermal treatment, in which at the first stage of processing there is a partial hydrolysis of polysaccharides (primarily water-soluble and easily hydrolyzed) with the formation of some quantities of organic acids, which carry out the hydrolytic cleavage of the natural ligno-carbohydrate complex, since it is known that at least small amounts of an acid catalyst are required to destroy the chemical bond between lignin and carbohydrates.

As a result of these processes, not monomers appear, but larger molecules that retain the natural reactivity of the main components of wood - carbohydrates and lignin. Wood in the manufacture of plastics should not be subjected to deep destruction, since this destroys the reactive components of natural wood.

In the process of piezothermal treatment, it is also necessary to provide opportunities for subsequent interaction between the reactive components of individual wood particles in order to synthesize new ligno-carbohydrate complexes. Thanks to this, the formation of durable and water-resistant plastic from wood particles occurs. New materials named ligno-carbohydrate wood plastics(LUDP). Ligno-carbohydrate wood plastic (LUDP) is a new board material obtained by hot pressing wood particles without the addition of binders. Ligno-carbohydrate wood plastics have a number of features that make their production economically viable:

1. The main advantage of LUDP, from this point of view, is that there is an unlimited amount of raw materials for their manufacture. These are wood particles of any of the most common conifers (pine, larch, spruce, cedar, fir) and deciduous species (birch, aspen, etc.), as well as their mixtures.

The production of LUDP can be established in any region of our country where logging and woodworking enterprises operate, since plastics can be made from any waste from logging and wood processing, as well as from firewood (without limiting the content of rot and bark).

On the basis of technical and economic calculations, it has been established that the minimum capacity of the workshop for the production of LUDP is 3.5-4 thousand m 3 of plates per year; the demand for raw materials for such a shop is 10-12 thousand m 3. Consequently, the production of LUDP, in contrast to the production of particle boards, can be organized in small enterprises.

2. Ligno-carbohydrate wood plastics are obtained by using the reactivity of the components of the wood itself, ie, without adding thermosetting resins or other binders to wood particles.

3. The technological process of LUDP production in comparison with the production of particle boards is simpler, since there are no technological operations for the preparation of binders and mixing them with wood particles.

4. For the manufacture of LUDP use standard pressing and other equipment used for the production of particle boards and serially produced by the domestic industry.

Basic technical properties of flat single-layer LUDP the following:

1. Appearance and color... After pressing, LUDP boards have a middle, darker (conditioned) part and a light edge along the periphery, or substandard part of the board. Substandard part of the slab at optimal conditions pressing does not exceed 10 cm. When using plates big size a 10 cm wide edge makes up only 2-5% of the area of ​​the pressed board. For example, with the size of the pressed plates 3100X1100 mm, the edge with a width of 10 cm is 2.5% in area. The width of the substandard part of the slabs can be reduced.

The color of the conditioned part of the board, pressed under optimal conditions, depends on the tree species from which the plastics are made, but is always much darker than that of the original wood and ranges from light to dark brown. The bark disturbs the uniformity of color. By coloring the wood particles of the outer layers of the formed carpet and making slabs faced with various decorative materials, it is possible to change the color and appearance of the slabs.

2. Surface quality... Boards made from fine and flat wood particles have a smoother and more even surface than boards made from thick and coarse wood particles. When pressing plastics from small wood particles on well-finished (better polished) pallets, the boards have a smooth, shiny surface.

3. Warping... The warpage of the LUDP depends on the thickness and design of the slabs. Thin slabs tend to warp more than thick slabs. Three-layer slabs warp less than single-layer slabs, and slabs lined with veneer are somewhat more warped than non-lined ones. In order to avoid warping of the LUDP boards during conditioning, the rules for laying the boards must be strictly followed and the modes of their conditioning - drying must be observed.

4. Density... The density of ligno-carbohydrate wood plastics cannot be less than 1 g / cm 3. Only at this density is the minimum degree of compaction of the pressed mass ensured, at which the necessary contact and the possibility of chemical interaction between individual wood particles are achieved.

5. Moisture absorption... LUDP to a certain extent retains one of the main features of wood - to absorb moisture from moist air. With an increase in the content of hygroscopic moisture in plastics, their mechanical properties decrease:

a) LUPD with a density of not less than 1.2 g / cm 3 have a swelling of 7-10%, water absorption 5-12%, total moisture content 20-22%;

b) LUDP with a density of 1.20-1.15 g / cm 3; swelling 10-12%, water absorption 12-15%;

c) LUDP with a density of 1.15-1 g / cm 3; swelling 18-25%, water absorption 20-26%.

6. Thermal properties... The material used for floors in residential and industrial buildings is characterized by a coefficient of heat absorption, which should not exceed 10 kcal / m 2.

Lignocarbon wood plastics with a thickness of 10-11 mm allow you to arrange floors by directly laying them on a concrete base.

7. Biostability... LUDP have a high anti-rotting resistance, which is 4-5 times higher than that of pine wood.

Mechanical properties of LUDP... Flat single layer uncoated LUDP slabs can be divided into three groups.

Group A - ultimate strength in static bending not less than 270 kg / cm 2 (density more than 1.2 g / cm 3), group B - ultimate strength in static bending not less than 220 kg / cm 2 (density 1.2-1, 18 g / cm 3); group B - ultimate strength in static bending not less than 120 kg / cm 2 (density 1.15-1 g / cm 3).

The physical and mechanical properties of ligno-carbohydrate wood plastics obtained from spruce logging residues are as follows: the ultimate strength in static bending is 170-190 kgf / cm 2, the swelling in 24 hours is 8-11%, and the density is 1.2 g / cm 3. Plastics made from crushed (1: 1 mixture) of birch and aspen have a static bending strength of 176 kgf / cm 2, swelling in 24 hours - 16% and a density of 1.18 g / cm 3.

Manufacturing process is generally the same for all types of single layer, unfaced lignocarbohydrate plastics. The only difference is that for each specific type of raw material used for the manufacture of LUDP, different preparation of raw materials and different modes of pressing and conditioning of plastics are required. Therefore, organizations industrial production plastics at a particular enterprise should be preceded by research work aimed at clarifying the technology for their manufacture from available raw materials. These studies can be carried out in parallel with the design and construction of the plastics manufacturing plant.

In general, the technological process of LUDP production consists of the following main operations: preparation of raw materials, drying of raw materials, dosing of wood particles, forming a carpet (package), cold pre-pressing of a carpet (package), hot pressing and cooling, hot pressing mode, cutting boards, conditioning - drying of plastic plates.

Scheme of the technological process for the production of LUDP by hot pressing from sawmilling and woodworking waste using one hydraulic press.

Branches, small-sized trunks, rotten spitting out of firewood, etc. are crushed on a chipper or crusher and fed by a conveyor or pneumatic conveyor into a hopper for a stock of chopped wood pulp, which can also receive sawdust, shavings or screenings from technological chips, chip production, etc. To obtain conditioned wood particles, wood pulp, previously cleaned of metal inclusions using a metal detector, is passed through a DO-5,7 chip machine, and then through cross-shaped mills of the DM-3 brand. The sieve drum openings of mills for some rocks are reduced to 3 mm. After crushing, wood particles are sucked in by a fan and transported to a cyclone installed under the metering hopper.

The dosing device of this hopper allows you to change the amount of dispensed chips per unit of time, which is necessary to maintain the required temperature regime in the chamber of the drying plant.

The shavings are loaded into the installation chamber by a screw conveyor.

The fluidized bed dryer consists of two parallel sections. The drying agent is heated air. Air is blown in by fans. Crushed crushed to the required moisture content through the drain thresholds of the drying chambers enters the sluice feeders, and then into the suction pneumatic conveying pipeline. The air, passing through the layer of shavings in the drying chambers, carries away dust, which settles in the cyclone with an increased cleaning coefficient. Air cleaned of dust, but with high humidity is emitted into the atmosphere, and the dust is sent together with the bulk of the material to the dry chip bin.

From this hopper, the shavings are uniformly fed by the dispensing device onto the belt conveyor 2 to the feeders and are distributed over the forming machines with fractionating rollers. The machines are laying the carpet on pallets. The formation of the sides of the carpet is carried out by two, vertical belt conveyors. Then the pallet with the loose carpet laid on it is moved by another section of the chain conveyor to press the carpet into a cold pressing press. The carpet is pressed under a pressure of 25 kg / cm 2 for 1 minute.

Before loading the package into a cold press, a duralumin gasket is placed on top using a rebar with suction cups. This contributes to uniform heating of the package and allows you to get a board with a high-quality surface on both sides.

Packages are collected in the press loading rack. After the stack is completely filled, all press spans are loaded simultaneously.

After the end of pressing, all plastic slabs are simultaneously unloaded into an unloading stacker, from which they successively, starting from the bottom, are fed to the longitudinal and transverse conveyors.

Plates of plastic are transferred from the lower pallet to the three-sawing machine by the removal mechanism. The pallets, after cleaning and applying talcum powder, are directed under the forming machines.

Plates of plastic, after trimming the light edges, are sorted. Rejected slabs are cut into smaller ones with cutting out defective places. After sorting, high-quality slabs are stacked on pads and loaded into the conditioning and drying chambers using a traverse trolley. After unloading from the chambers, the slabs are placed in dense stacks in a heated room. Then they are packed and sent to the finished product warehouse for shipment to the consumer. (Technological operations following the cutting of plastic slabs are not shown in the diagram.) It is possible to increase the productivity of the LUDP workshop by increasing the size of the slabs, the number of stories of presses or their number.

High physical and mechanical properties of LUDP, beautiful appearance and the ability to manufacture large slabs allow them to be used in construction as a structural and finishing material for flooring, filing ceilings, manufacturing of built-in furniture, installation of partitions, door panels, window sills, for cladding walls and panels in public buildings, in kitchens and corridors of residential buildings, etc., in furniture and other industries, as well as as a substitute for solid wood, particle boards, fibreboards and other sheet materials. Plates have smooth surface and get off well with transparent and opaque varnishes and paints using conventional technology. Finishing with transparent furniture varnishes can be done with preliminary tinting of the surface with water-soluble and other dyes in any color while maintaining the texture of the boards.

Thus, when crushing branches and small size, the yield of conditioned chips is on average 50% of the total crushed mass. These conditioned chips can be used to make semi-cellulose, make particle boards and fibreboards, and 50% substandard chips can be used to make ligno-carbohydrate wood plastics or fertilizers.

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