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Wood plastic. Wood-polymer composite or liquid wood. Application and processing

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

  1. As the main business for the manufacture of finished products and molds by casting from: liquid:
    • plastic;
    • silicone;
    • polyurethane;
    • transparent resins and other materials.
  2. Mold making as an effective addition to other types of business in the area:
    • construction;
    • Food Industry;
    • soap making.

In the first and second cases, casting 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 it is possible to produce plastic products in small batches at home:

  • souvenir products;
  • toys;
  • bijouterie;
  • spare parts for autotuning;
  • 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 Axson FASTCAST F32 brand from a French manufacturer makes it possible to obtain a super-liquid plastic that flows into the smallest folds of the relief of the model's shape. In addition, it is harmless to children and has no smell.

Preparation for production

To organize production, first of all, a sample model is required. According to it, you first need to make a mold 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 can even see fingerprints on products (if necessary). That is, a copy will turn out at the level of identity, which cannot be distinguished with the naked eye. Plastic products can be given complex compounds with any relief. 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 a 3D printer. By the way, injection molding significantly exceeds the productivity of 3D printing from plastic.

When your product is ready, you can decorate it with the help of related products that are attached to 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 may affect performance. But the creation of each business is undoubtedly a creative process. After all, financial management is an art.

We make a product from liquid plastic

Technology for creating an ideal small relief in the manufacture of a silicone mold with your own hands. First you need to prepare all the components and materials. We will need:

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

We securely fix the model-sample at the bottom of the formwork to form the form, using neutral wax clay (to avoid silicone leakage). We paint silicone, from which to get finished form in scarlet color, so that the quality of kneading the components of liquid, white to the color of plastic can be clearly seen on the form. Useful advice: in order for the shape to be perfect, the sample model should first be smeared with silicone using a wide brush. In this way, carefully fill in all the recesses of the relief of the compound. Only after that, fill the form completely. We fill the entire formwork with silicone. We leave to fix the structure of the form for 7-8 hours. The hardest part is over.

Congratulations!!! Now you have a ready-made form for the repeated production of copies of the sample model. Make sure the mold is completely dry before casting to avoid 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 scale). The setting time is 7 minutes, but it will take another 20 minutes to fully consolidate. This plastic is neutral to silicone and does not stick to it. But after repeated use of the compound over time, you may need a lubricant release agent with the protective properties of EaseRelease. After the required time has elapsed, we take out the finished product, which is copied exactly according to the model.

Polyurethane molds for construction

Together with plastic products casting molds can be produced. The use of injection molds in construction is now very popular. It is possible to produce compounds for the production of building materials. They are durable and do not require treatment with special separating lubricants during manufacture. After all, concrete is absolutely neutral to polyurethane. For example, liquid polyurethane compounds allow you to make molds for pouring:

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

Silicone molds for confectioner and soap making

The use of mold casting technology in the food industry is quite obvious. New innovative solutions in the field of chemistry today offer liquid: plastics, silicones, silicone masses that comply with all health standards and have the appropriate certificates. Such safe components can be used to produce molds for the food industry. For example, for production:

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

Compounds are also in great demand among soap makers. They are always in need of new original molds to create salable souvenirs made from soap. It is not at all difficult to find a customer who wants to make their products with a unique shape.

small business idea opportunities

This business idea makes it easy to create popular products with your own hands. Finished works can be sold through the online store. It is also possible to provide services or sell finished compounds to other manufacturers in other industries. Most importantly, with all these wide range of 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. Such a business idea is quite attractive for a home based business. It does not require a lot of costs, allows you to produce useful goods and captivates the creative process of production.

  1. Description and chemical composition
  2. The ratio of polymer and wood
  3. Material Advantages

In construction and in the manufacture of furniture, new high-tech materials with improved properties are used, compared with conventional ones of the same class, and their price is lower. One such material is wood-polymer composite (WPC). Now it is widely distributed, which is associated with availability and low price. It is cheaper than regular wood but has the same strength.

In the manufacture of the composite, natural wood and a polymer that does not harm human health are used. Usually, WPC is obtained by casting, which significantly increases its strength.

Composite can be used when laying flooring. It is used when installing railings on open terraces, in gazebos, on balconies, as it is resistant to temperature extremes, any precipitation, mechanical stress. This makes the WPC versatile. The material has a beautiful structure.

WPC is widespread in the USA, where it is actively used in the construction of cottages.. It is important to know the production technology, characteristics, if you have chosen this material. If you know the features of the liquid wood manufacturing process, then you can make a composite with your own hands.

Description and chemical composition

Wood-polymer composite, which is called liquid wood, is an artificial material obtained by mixing wood and a monomer. During the manufacturing process, extrusion takes place, forming a polymer. In a similar way, a polymer board is made, which is superior in strength to ordinary wood, but slightly inferior ceramic tiles. The boards themselves take shape during the casting process.

Produced " liquid tree» by adding binder polymers to the chips: polystyrene, polyethylene, polypropylene and polyvinyl chloride. WPC received the name "liquid tree" because of its flexibility and plasticity..

"Liquid tree" is used in the production of floorboards, siding, pipes (for plumbing, sewage), furniture.

The chemical composition of WPC includes only 3 components:

  1. Small particles of wood (shavings, sawdust, shredded wood, abroform, cheap models come across cake from sunflower seeds, shredded plywood). The amount of additive can vary in composition from 1/3 to 4/5 of the total mass.
  2. Polymer additive - polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP).
  3. Special chemical additives which significantly improve technical properties, appearance(dyes, varnishes). The volume of these additives is 0.1–4.5% of the total mass.

The ratio of polymer and wood

The proportions of the ratio of polymer and wood can be different. The selection is made taking into account technical indicators DPC is required.

The ratio of wood (abroform) to polymer is 2:1. This ratio gives the WPC the properties of wood - the mass will contain more wood fibers. Boards made of such material will swell from moisture, which significantly reduces the service life in a humid climate. For the central zone and the south of Russia, it will be 5–10 years. WPC is relatively fragile, which limits its use, but the building material has a beautiful wood texture and a “corrugated” surface.

The ratio of wood to polymer, like 2:3, significantly impairs the appearance of the WPC board, which limits the use of boards for decorative purposes. To the touch, the board resembles ordinary plastic, and the surface becomes smoother (sometimes slippery).

If the wood-polymer composite has a ratio of wood fibers (abroform) to polymer 1:1, the board acquires optimal characteristics. The texture is beautiful, with a rough surface, non-slip. The casting process is simplified: there is no need to heat the components to the desired temperature. The preparation of WPC in this way does not transfer the properties of wood to the material: it does not absorb moisture, does not swell, and is relatively durable in use.

Liquid wood is poured into special forms, which provide for the presence of spikes and grooves for attaching boards.

Material Advantages

WPC is resistant to ultraviolet radiation: it does not crack, does not deform. It does not change its structure when low temperatures air, exposure to moisture, acids and other negative environments.

The material is resistant to mold, insects do not start in the WPC, it is not a bait for mice, rats and other rodents. For greater stability, it can be covered with a special polymer film.

Another plus is higher strength (allows you to withstand more than 5 centners per 1 m 2). This makes it possible to place any heavy furniture on the boards.

Liquid wood is a flexible material that can be easily processed.. It can be sawn, planed. This is taken into account in the production of polymers or in the casting process.

Liquid wood is an environmentally friendly material, since the used abroform and polymer do not emit toxic substances and do not pose a danger to humans. WPC is non-flammable and does not support combustion.

Is it possible to make it yourself?

It is possible to make a “liquid tree” (abroform) at home, while a do-it-yourself WPC will have the necessary characteristics. The blanks are suitable for restoration work (furniture), rough flooring for auxiliary rooms, gazebos, terraces.

To make a liquid tree, you need to take sawdust and grind them with home mills or coffee grinders. PVA glue is added to the mixture (the ratio of sawdust and glue is 70:30). The resulting mixture should be thick. For the material to have desired color, it is recommended to add paint (enamel) of a suitable color.

The resulting mass is an analogue of the WPC. The material can be applied to damaged areas of parquet, laminate, furniture.

If you fill the floor with such material, then under it you need to make a formwork, and prepare the mixture itself in the right amount. Then you can start filling. The recommended thickness of the future board is 50 mm.

Consumption ecology. Science and technology: People have learned how to turn natural materials processing waste into products that are ahead of these materials in terms of properties. From the article you will learn about a completely new material - wood-polymer composite or WPC.

The last 40 years of industrial development can be safely called the “era of combined materials”. Modern equipment and technologies make it possible to connect seemingly incompatible: wood, concrete, plastic, paper, metal. All of them mix, diffuse, fuse with one goal - to get New Product combining the best properties of several raw materials. So, among other novelties, we saw a “liquid tree”.

What is a "liquid tree"

In technical terms, this is an extruded wood-polymer composite (WPC). This means that the wood component is preserved with plastic. In this combination, the material takes on the best properties:

  1. From wood - compressive strength, impact resistance, elasticity. At the same time, the wood component is practically free - any waste ground into flour is used.
  2. From plastic - corrosion resistance, flexibility, processing accuracy. The polymer envelops wood particles and eliminates the main disadvantage of wood - destructive reactions with water. The polymer in this technology is 90% recycled plastic, i.e. recycled waste.

The technological process is easy to understand, but quite difficult to execute. The polymer (plastic) is mixed in a certain proportion with wood flour and heated so that it melts. Then molded in an extruder, on rollers or in molds and cooled. At different stages, about 10 different additives are mixed into the mass - plasticizers, catalysts, hardeners and others. All manufacturing details - wood type and plastic brand, mixture proportions, additives, temperature conditions, as a rule, constitute a trade secret. It is known that all ingredients can be purchased freely, and for wood flour, bamboo, larch and other durable species of the middle price category are mainly chosen.

For the manufacture of WPC, special multi-stage production lines are created. They consist of many devices and controllers. Unfortunately, it will not work to assemble such a machine with your own hands in the garage. But you can buy a ready-made production line.

WPC products

Currently, the product range is incomplete, because the material is relatively new and its properties have not been fully studied. However, several of the most popular positions can already be mentioned.

Terrace board or decking

It makes up to 70% of all demanded products from WPC today. Most of the supplied production lines is focused on the release of just such a board, because it is currently the only alternative to wood. The board consists of a perimeter frame, stiffening ribs inside and has a tongue-and-groove fastening system. Various colors are offered.

Advantages over traditional material: WPC board is favorably distinguished from wood by continuous coloring and better physical indicators (strength, flexibility, processing accuracy). Many types of WPC boards are produced double-sided - with solid wood reliefs and ribbed cutting.

WPC terrace board on video

Cladding facade panels or planken

By and large, they can be correlated with vinyl siding - the principle of installation and the structure of the panel are very similar. But the WPC panel is much thicker and stiffer, respectively, has more weight and better physical properties.

Advantages over traditional material: a stronger and more durable facade, panel cavities and thick walls better retain heat and absorb noise.

Fences, railings, railings, balustrades

Forms of small architecture from "liquid wood" for decorative finishes exterior and landscape. They have good bearing capacity and are suitable for intensive use (in crowded places).

It was customary to make such products from wood (short-lived and requiring maintenance) or concrete (heavy, cold and not always reliable). Wood-composite forms are made prefabricated, and all the details are designed in advance. On the spot, it remains only to assemble them with a grinder and a screwdriver. Such a fence does not require a powerful foundation, permanent painting. In case of damage to a section or structural element, it can be easily replaced by manufacturing the required number of additional parts.

The general advantage is absolute insensitivity to atmospheric wear (moisture, frost, overheating in the sun), insects, fungi and abrasion.

A common disadvantage is the relatively large fluctuations during heating and cooling. The expansion of the WPC terrace board can be up to 6 mm per 1 m (with gradual heating up to +40 °C).

Prices for facade panels made of "liquid wood"

Name Manufacturer Characteristics The price of 1 m 2, at. e.
Duo Fuse FPS-22 Belgium 2800x220x22 mm, PVC 35
"MultiPlast" Russia 3000x166x18 mm, PE 20
RINDEK Russia 3400x190x28 mm, PVC 22
MultiDeck Chalet China 2900x185x18 mm, PE 17
CM Cladding Sweden 2200x150x11 mm, PVC 28
ITP ("Intechplast") Russia 3000x250x22 mm, PVC 26
DORTMAX Russia 4000x142x16 mm, PE 18

How to choose a deck board from WPC

Any kind of "liquid tree" is made from wood flour, the composition of which is not so important. But the composition of the polymer that is added to it can be critical:

  1. Polyethylene based polymer. Easier and cheaper to manufacture. Contains a larger amount of sawdust, due to which it is cheaper than analogues. Exposure to UV radiation (no additives).
  2. PVC polymer. More resistant to temperature extremes, ultraviolet, greater fire safety. Longer lasting 2 times compared to other formulations.

According to the type of profile, terrace boards are divided into two types:

  1. Full bodied. Withstand significant shock loads. Well suited for places with high traffic - summer cafes and verandas, ship decks, embankments and piers.
  2. Hollow. They are light in weight. Suitable for terraces of private houses.

According to the type of connection, WPC boards are divided into:

  1. Suture. They are mounted with a gap of 3-5 mm and provide good water drainage. Attached with metal or plastic clasps.
  2. Seamless. They create a continuous durable surface due to mutual adhesion. Mounted with self-tapping screws, clamps are not required. Suitable for summer cafe areas - small things, heels, etc. do not fall into the gaps.

By type of anti-slip coating or treatment:

  1. Processed with brushes ("brushing" from the English brush - brush, brush). Surface created with a metal brush (artificial aging).
  2. Sanded. The surface is treated with an emery cloth.
  3. Embossed. As a rule, they are executed in a tree structure. Good decorative look, but in passable places the pattern wears out and it becomes noticeable.
  4. Co-extrusion. The top layer is made of a high-strength compound and is structured during the extrusion of the board itself.
  5. Co-extrusion with deep embossing (from the English embossing - embossing). The embossing on the top layer imitates precious woods.

What to look for, regardless of the type of board you choose:

  1. Rib height. The strength of the board depends on it.
  2. The number of stiffeners. Affects the bending strength - the more of them, the higher the strength.
  3. Wall thickness. Thin walls (2-3 mm) do not hold shock loads well.
  4. Board width. The wider the board or panel, the faster and easier installation and fewer fixtures are required.

Video - how to choose a WPC terrace board

Quite rightly, you can take this advice in relation to facade panels and other WPC products for facing planes.

The industry provides the layman with the opportunity to make his choice - to use a new natural material, which is used by natural resources (wood, stone) or to use recycled products. Today, people have learned to turn waste from the processing of natural materials into products that outperform these materials in terms of properties. However, the choice remains with the person - either to dispose of garbage, acquiring WPC, or to create more and more of it, giving preference to natural materials. published

480 rub. | 150 UAH | $7.5 ", MOUSEOFF, FGCOLOR, "#FFFFCC",BGCOLOR, "#393939");" onMouseOut="return nd();"> Thesis - 480 rubles, shipping 10 minutes 24 hours a day, seven days a week and holidays

Savinovskikh Andrey Viktorovich. Obtaining plastics from wood and plant waste in closed molds: dissertation ... candidate of technical sciences: 05.21.03 / Savinovskikh Andrey Viktorovich; [Place of protection: Ural State Forestry Engineering University].- Yekaterinburg, 2016.- 107 p.

Introduction

CHAPTER 1 Desk Review 6

1.1 Wood-composite materials with synthetic binders 6

1.2 Lignocarbon and piezothermoplastics 11

1.3 Ways to modify wood particles 14

1.4 Lignin and lignocarbohydrate complex 19

1.5 Cavitation. Cavitation treatment of vegetable raw materials 27

1.6 Bioactivation of wood and plant particles with enzymes.. 33

1.7 Selection and justification of research direction 35

CHAPTER 2. Methodical part 36

2.1 Characterization of starting materials 36

2.2 Measurement techniques 41

2.3 Preparation of bioactivated press material 41

2.4 Making samples of DP-BS 41

2.5 Preparing a weighed amount of press material for plastics 42

CHAPTER 3 Obtaining and studying the properties of wood-based plastics without a binder using modifiers 43

CHAPTER 4. Effect of chemical modification of wheat hulls on the properties of RP-BS 57

CHAPTER 5. Obtaining and studying the properties of wood-based plastics without a binder using bioactivated press raw materials 73

CHAPTER 6. Technology for obtaining DP-BS 89

6.1 Calculating the output of an extruder 89

6.2 Description of the manufacturing process 93

6.3 Cost estimate finished products 95

Conclusion 97

Bibliography

Introduction to work

Relevance of the research topic. The volumes of production of processed wood and vegetable raw materials are constantly increasing. At the same time, the amount of various wastes from wood processing (sawdust, shavings, lignin) and agricultural plants (straw and shells of cereal seeds) also increases.

In many countries, there are production of wood composite materials using synthetic thermosetting and thermoplastic organic and mineral binders as a polymer matrix, crushed waste as fillers. plant origin.

Known is the possibility of obtaining wood composite materials by flat hot pressing from wood waste without the addition of synthetic binders, which are called piezothermo plastics (PTP), lignocarbon wood plastics (LUDP). It is noted that the original press compositions have low plastic-viscosity properties, and the resulting composites have low physical and mechanical properties, especially water resistance. And this requires the search for new ways to activate the lignin-carbohydrate complex.

Thus, works aimed at the use of wood and plant waste without the use of synthetic binders in order to create products are relevant.

The work was carried out on the instructions of the Ministry of Education and Science of the Russian Federation, project No. 2830 "Obtaining wood plastics from waste biomass of wood and agricultural plants" for 2013-2016.

Purpose and tasks of the work. The aim of the work is to obtain plastics from wood (DP-BS) and agricultural waste (RP-BS) without the addition of synthetic binders with high performance properties.

To achieve this goal, it is necessary to solve the following tasks:

To study the process of formation of DP-BS and RP-BS based on wood (pine sawdust) and vegetable (wheat husk) waste.

To study the influence of chemical modifiers, as well as technological parameters (temperature, humidity) on the physical and mechanical properties of DP-BS and RP-BS.

Determine the rational conditions for obtaining DP-BS and RP-BS from wood and plant waste.

To establish the effect of bioactivation of press raw materials with activated sludge on the physical

co-mechanical properties of DP-BS.

The degree of development of the research topic. An analysis of scientific, technical and patent literature showed a very low degree of development of issues related to the patterns of formation of the structure and properties of wood plastic without a synthetic binder.

Scientific novelty

    The kinetic regularities of the process of formation of DP-BS and RP-BS (activation energy, pre-exponential factor, reaction order) were established by DSC.

    The effect of chemical modifiers (hydrogen peroxide, urotropine, isomethyltetrahydrophthalic anhydride, cavitation lignin, hydrolytic lignin) on the rate of formation of DP-BS and RP-BS has been established.

    The kinetic regularities of obtaining DP-BS with the use of bioactivated wood waste are obtained.

Theoretical significance work is to establish patterns of influence of a number of modifiers and moisture content of press raw materials from wood and agricultural waste on the physical and mechanical properties of DP-BS and RP-BS.

Practical significance The work consists in the use of renewable raw materials waste and experimental proof of the possibility of obtaining DP-BS and RP-BS with improved physical and mechanical properties. A recipe for obtaining DP-BS and RP-BS is proposed. DP-BS products have low formaldehyde emission.

Methodology and research methods. The work used the traditional methodology scientific research and modern research methods (differential scanning calorimetry, IR Fourier spectroscopy, PMR 1 H).

Taken for defense

The results of the study of the thermokinetics of the formation of DP-BS, RP-BS and the influence of modifiers and humidity on this process.

Patterns of the formation of the properties of DP-BS and RP-BS in closed molds under the influence of temperature, humidity of the press raw material and its chemical modification.

The degree of reliability of research results provided by repeated repetition of experiments, the use of methods of statistical processing of the obtained measurement results.

Approbation of work. The results of the work were reported and discussed at the VIII international scientific and technical conference "Scientific creativity of youth - the forest complex" (Yekaterinburg, 2012), the IX international scientific and technical conference "Scientific creativity of youth - the forest complex" (Yekaterinburg, 2013), the International Conference "Composite materials on wood and other fillers” (Mytishchi, 2014).

Publications. Based on the dissertation materials, 12 articles were published, including 4 articles in publications recommended by the Higher Attestation Commission.

Workload

The dissertation is presented on 107 pages of typewritten text, contains 40 tables and 51 figures. The work consists of an introduction, 6 chapters, a conclusion, a list of references, including 91 references to domestic and foreign works.

Lignocarbon and piezothermoplastics

Lignocarbohydrate and piezothermoplastics. These materials are made from sawdust or other vegetable raw materials by high-temperature processing of the press mass without the introduction of special synthetic binders. The technological process for the production of lignocarbon wood plastics consists of the following operations: preparation, drying and dosing of wood particles; carpet forming, cold pressing, hot pressing and cooling without pressure relief. When preparing the press mass, wood particles are sorted, then a fraction larger than 0.5 mm is additionally crushed, conditioned sawdust is fed into the dryer, and then into the spreader. The carpet is formed on pallets coated with a layer of talc or release agent. First, the finished carpet is fed into a press for cold pre-pressing, which lasts for 1.5 minutes at a pressure of 1-1.5 MPa, after which it is sent for hot pressing at a pressure of 1.5-5 MPa and a temperature of 160-180 C. Pressing plates 10 mm thick lasts 40 min.

Under the influence of temperature, partial hydrolysis of wood polysaccharides and the formation of organic acids occur, which are catalysts that contribute to the destruction of the lignocarbohydrate complex. The resulting reactive products (lignin and carbohydrates) interact with each other during pressing. The result is a denser and stronger material than wood.

Raw materials for the production of lignocarbon wood plastic are obtained by processing coniferous and hardwood. Along with sawdust, machine shavings, crushed wood, bark mixed with wood, crushed logging waste and some lignified agricultural waste can be used to produce plastic. Impurities in the raw materials of partially decayed wood improve the physical and mechanical properties of lignocarbon plastics.

Compared to particle boards, lignocarbon plastics have a number of advantages: they are not subject to aging due to the degradation of the organic binder and their strength properties do not decrease with time; during operation there are no toxic emissions in environment. Significant disadvantages of the production of lignocarbon plastics are the need for powerful press equipment and the duration of the pressing cycle.

It is noted that under the influence of pressure and temperature, the crushed plant material acquires the ability to form a strong and solid dark-colored material that can be molded. This material is called piezothermoplastic (PTP).

The feedstock, along with sawdust, can be crushed wood of coniferous and hardwood, flax and hemp fire, reeds, hydrolytic lignin, odubina.

There are several ways to obtain DRAs that have undergone deep study and introduction into production, but have not found further application due to high energy costs: 1) a one-stage method for obtaining DRAs (A.N. Minin, Belarusian Technological Institute); 2) a two-stage method for producing plastics from hydrolyzed sawdust (N.Ya. Solechnik, Leningrad LTA); 3) technology for obtaining lignocarbohydrate wood plastics (LUDP) (VN. Petri, Ural LTI); 4) steam explosion technology (J.A. Gravitis, Institute of Wood Chemistry, Latvian Academy of Sciences). Piezo thermoplastics are divided into insulating, semi-hard, hard and super-hard.

At medium density 700-1100 kg/m3 piezothermal plastics made from birch sawdust have a static bending strength of 8-11 MPa. With an increase in the average density to 1350-1430 kg/m3, the ultimate strength in static bending reaches 25-40 MPa.

The high physical and mechanical properties of piezothermoplastics make it possible to use them for the manufacture of floors, doors, and also as finishing material. A variety of wood plastics is a vibrolite, technological features which consist in the partial grinding of sawdust and small chips on a vibrating mill, mixing the finely ground mass with water, and then we get the sludge. From a mixture of sludge with particles of 0.5-2 mm in size, a carpet is formed in the casting machine, which is dehydrated by a vacuum pump. The resulting press mass is fed to cold and hot pressing. The finished boards are transported to the hardening chamber, where they are subjected to heat treatment for 3-5 hours at a temperature of 120-160 C, as a result of which their water absorption is reduced by almost 3 times and swelling by more than 2 times.

Vibrolit is used for subflooring, partitioning, wall panels in public buildings, built-in furniture and panel doors.

Since the 1930s in the USSR, many researchers have been engaged in the production of plate materials by piezothermal processing of plant materials without the use of traditional binders. The work was carried out in the following areas: 1) pressing natural, untreated sawdust; 2) pressing sawdust, pre-autoclaved with steam (pre-hydrolysis) or steam with a catalyst (mineral acid); 3) pressing of sawdust pre-treated with chemical reagents: a) gelatinization of the press mass (with chlorine, ammonia, sulfuric acid, and other substances) for its partial hydrolysis and enrichment with substances with binding properties; b) chemical polycondensation of the press mass with the participation of other chemicals (furfural, phenol, formaldehyde, acetone, alkaline and hydrolytic lignins, etc.).

Preparation of bioactivated press raw materials

The endothermic minimum corresponds to the process of hydrolysis of the lignin-carbohydrate complex and the easily hydrolyzed part of cellulose (polysaccharides).

The exothermic maximum corresponds to the processes of polycondensation, which determine the process of formation of DP-BS. Since the process is catalyzed by acids that are formed during the pyrolysis of wood, as well as due to the presence of resin acids contained in the composition of extractives, this is an n-th order reaction with autocatalysis.

For wood waste with modifying additives (hydrogen peroxide, urotropine, IMTHFA), the peak maxima on the DSC curves shift to the left, which indicates that these compounds act as catalysts for the above processes (T1 100-120 0C, T2 180-220 0C), accelerating the process of hydrolysis of wood polysaccharides, as well as the lignin-carbohydrate complex.

Table 3.2 shows that at the first stage, with an increase in the moisture content of the raw material, the effective activation energy increases (from 66.7 to 147.3 kJ / mol), which indicates a greater degree of hydrolytic destruction of wood. The use of modifiers leads to a decrease efficient energy activation, which indicates their catalytic action.

The values ​​of the effective activation energy at the second stage of the process for the modified press material change insignificantly with increasing humidity.

The use of modifiers leads to a decrease in the effective activation energy at the second stage of the process. An analysis of the kinetic equations showed that the best model at the first stage of the process is an n-order reaction, at the second stage - an n-order reaction with auto-acceleration: A 1 B 2 C.

Using the kinetic parameters of the process, t50 and t90 (time required to reach 50 and 90% conversion) were calculated for unmodified and modified press feedstock (Table 3.3), and conversion curves are presented (Fig. 3.4-3.6) .

The dependence of the degree of conversion on time at various temperatures(pine, initial moisture content of press raw materials - 8%) Figure 3.5 - Dependence of the degree of conversion on time at different temperatures (pine, modifier - urotropin, initial moisture content of press raw materials - 12%)

Dependence of the degree of conversion on time at different temperatures (pine, modifier - hydrogen peroxide, initial moisture content of the press raw material - 12%) with humidity 8% Press material with moisture content 12% (modifier -1.8% H2O2, %) Press material with moisture content 12% (modifier - 4% C6H12N4, %)

The use of hydrogen peroxide leads to an acceleration of the process at the first stage by more than 4 times than when the press material is modified with urotropine. A similar pattern is observed at the second stage of the process. According to the total time of formation of DP-BS, the activity of the press material can be arranged in the following order: (unmodified press material) (press material modified with urotropin) (press material modified with hydrogen peroxide). In order to establish the influence of humidity and the content of the amount of the modifier in the press raw material on the operational properties of DP-BS, a mathematical planning of the experiment was carried out. A preliminary study was made of the influence of the moisture content of the initial press raw material on the physical and mechanical properties of DP-BS. The results are shown in table. 3.4. It has been established that the greater the initial moisture content of the press raw material, the lower the physical and mechanical properties, such as flexural strength, hardness, flexural modulus. In our opinion, this is due to a greater degree of thermohydrolytic destruction of the lignocarbohydrate complex. Table 3.4 - Physical and mechanical properties of DP-BS obtained at different moisture content of the press material

Thus, the physical and mechanical properties of DP-BS depend on the formulation and conditions for its preparation. So for plastic with high physical and mechanical properties, the following composition should be used: lignin content 3%, IMTHFA content 4%, initial moisture content of the press raw material 6% and hot pressing temperature 1800C. For plastics with low values ​​of water absorption and swelling, it is required to use the composition: 68% lignin content, 2% IMTHFA content, 17% initial moisture content of the press raw material and 195 C0 hot pressing temperature.

Effect of chemical modification of wheat husk on the properties of RP-BS

The depth of the thermohydrolytic degradation of wood and plant material lignin depends on the type of chemical modifier used.

Our studies of the formal kinetics of obtaining plastics show that lignin conifers(pine) is more reactive than lignin annual plants(wheat husk). These results are consistent with the results on the oxidation of model compounds of coniferous and hardwood lignin and plant lignin. An analysis of the literature showed that theoretical studies of the features of wood transformation under enzymatic effects made it possible to develop biotechnology for wood plastics based on the partial biodegradation of the lignocarbohydrate complex.

It is known that biotransformed wood particles significantly change their plasticity. Also, the species composition of wood raw materials has a significant impact on the physical and mechanical properties of plastic.

Bioactivated wood waste treatment various types ligno-destroying fungi, bacteria, in our case, activated sludge, is promising for the manufacture of press raw materials for DP-BS(Au).

Initially, the regularities of the process of obtaining DP-BS (Au) based on wood waste using activated sludge (Fig. 5.1) with different bioactivation periods were studied. 0.5 7 days 14 days

The study of the process of formation of DP-BS(Au) by DSC showed that the curves w = f(T) (Fig. 5.2) have two exothermic maxima. This indicates that the process can be represented as two parallel reactions, corresponding to bioactivated and non-activated press materials, i.e. A 1 B and C 2 D. In this case, reactions 1 and 2 are n-order reactions).

The kinetic parameters of the formation of DP-BS(Au) have been determined. The results are shown in table. 5.1. Table 5.1 - Kinetic parameters of the process of formation of DP-BS(Au)

At the second stage of the process of obtaining DP-BS(Au), the values ​​of the effective activation energy are of the same order as for wood press raw materials (see Chap. 3). This indicates that this exothermic peak corresponds to a non-bioactivated wood press. Using the kinetic parameters of the process, t50 and t90 (the time required to reach the degree of conversion of 50 and 90%) of the modified press raw material were calculated (Fig.5.3, 5.4).

Figure 5.3 - DP-BS(Au) conversion times at different temperatures (bioactivation time 7 days) Figure 5.4 - DP-BS(Au) conversion times at different temperatures (bioactivation time 14 days)

In order to establish the effect of activated sludge and cavitation lignin on the physical and mechanical properties of DP-BS(Au), an experiment planning matrix was compiled based on regression fractional mathematical planning of the form 25-1 (see Table 5.2).

The following factors were used as independent factors: Z1 – cavitation lignin content, %, Z2 – hot pressing temperature, C, Z3 – activated sludge consumption, %, Z4 – holding time (bioactivation), days; Z 5 is the initial moisture content of the press raw material, %.

The output parameters are: density (P, kg/m3), bending strength (P, MPa), hardness (T, MPa), water absorption (B), swelling (L, %), modulus of elasticity in bending (Ei, MPa ), impact strength (А, kJ/m2).

According to the plan of the experiment, samples were made in the form of disks and their physical and mechanical properties were determined. Experimental data were processed and obtained by studying the regression equation in the form of a linear, polynomial of 1 and 2 degrees with an assessment of the significance of factors and the adequacy of the equations, which are presented in Tables 5.2-5.4. Table 5.2 - Planning matrix and experiment results (three-level five-factor mathematical plan) a) hot pressing temperature and cavitation lignin content; b) consumption of ion mixture and pressing temperature; c) humidity of press raw materials and duration of bioactivation; d) the duration of bioactivation and the content of cavitation lignin.

It has been established that the density of DP-BS(Au) with an increase in the content of cavitation lignin in the press raw material is of an extreme nature: the minimum density of 1250 kg/m3 is achieved at a CL content of 42%. The dependence of the density of DP-BS(Au) on the duration of the bioactivation of the press raw material also has an extreme character and the maximum value is reached at 14 days of bioactivation (Fig. 5.5c).

Finished product cost estimate

Conducted studies on the production of DP-BS, DP-BS(Au) and RP-BS (see Chap. 3,4,5) show that the physical and mechanical properties of plastic depend on the formulation of the press raw material, the type of chemical modifier and the conditions for its manufacture .

In table. 6.1 shows the physical and mechanical properties of plastics (DP-BS, DP-BS(Au) and RP-BS) obtained under rational conditions.

From the analysis of the results obtained (Table 6.1), it can be seen that for the manufacture of products with high physical and mechanical properties, a press composition of the following composition is recommended: wood waste (pine sawdust), modifier - hydrogen peroxide (consumption - 1.8%) initial humidity - 12%.

To increase productivity, an extrusion method is proposed, which allows the production of molded products.

The dissertation work considers the production of plinth. In order to comply with the conditions defined for hot pressing in closed molds, the extrusion head consists of two parts (heated part of the head and the second part without heating). At the same time, the residence time of the press composition in the heated part of the extrusion head is 10 minutes.

To determine the annual production volume, an extruder performance calculation was performed.

For a single screw extruder with variable (reducing) depth cutting of the spiral channel, the calculation of volumetric productivity (Q, cm3/min) can be carried out as follows:

Here A1, B1, C1 are the constants of the direct and two reverse flows, respectively, at a variable screw cutting depth, cm3; Table 6.1 - Physical and mechanical properties of DP-BS, DP-BS(Ai) and RP-BS (summary table) No. p / p 1245 6 Moisture content of the raw material,% Modifier DP-BS (Ai) DP-BS RP-BS 12 % (4%-C6H12N4) 12% (1.8%-H202) CL - 3% Consumption AI-37% Humidity - 10% GL - 3% IMTHFA-4% Humidity - 6% GL - 68% IMTHFA-2, 5% Moisture - 17.9% Moisture - 12% HL - 3% Hydrogen Peroxide - 0.06% Moisture - 12% HL - 35% Hydrogen Peroxide - 5% Moisture - 12%

Bending strength, MPa 8 12.8 10.3 9.6 12.0 - 8 9.7 Hardness, MPa 29 29.9 27.7 59 69 20 19 34 Modulus of elasticity in bending, MPa 1038 2909.9 1038, 6 732.6 2154 1402 1526 1915 Water absorption, % 59.1 148 121.7 43 59 34 143 139 Swelling, % 6.0 12 8 3 5.0 1.0 7 7.0 1 K=0.00165 cm3; n – screw speed, n=40 rpm. where t is the cutting step, cm, it is assumed t = 0.8D; - the number of threading of the screw, =1; e is the width of the auger crest, cm; e = 0.08D; - coefficient of geometrical parameters of the screw:

The coefficients, a, b depend on the geometric dimensions of the screw. They are easy to calculate if there is a drawing of the screw, from which the following values ​​are taken: h1 - the depth of the spiral channel at the beginning of the feeding zone, cm; h2 is the depth of the spiral channel at the beginning of the compression zone, cm; h3 is the depth of the spiral channel in the dosing zone, cm; If the dimensions of the screw are unknown (with the exception of D and L, which are known from the brand of the extruder), then take h1=0.13D. After that, the remaining parameters are calculated: where L is the length of the screw, cm; L0 is the length of the screw up to the compression zone, cm; where Ln is the length of the pressure part of the auger, cm; Lн=0.5L. where i is the degree of compression of the material; i=2.1. The results of calculations using the above formulas allow us to calculate some other parameters of the screw.

Wood waste is sorted on vibrating screens (pos.1) from large particles, then wood particles pass through a metal detector (pos.3). The coarse fraction enters the hammer crusher (pos. 2) and then returns to the vibrating screen (pos. 1). From the vibrating sieve, small particles are pneumatically transported to a cyclone (pos.4), and then to a bin (pos.5), from where they are fed by a batch screw conveyor to a drum-type dryer (pos.6), wood particles are dried to a moisture content of 6%. Shredded wood waste enters the cyclone (pos.7), then into the dry shredded waste hopper (pos.8) with a screw conveyor, through which they are fed to the belt scales (pos.9).

The preparation of a hydrogen peroxide solution takes place in a tank (pos.10) for mixing with water. Hydrogen peroxide is dosed using scales (pos.11). The supply of the required amount of water is regulated by a flow meter. The concentration of hydrogen peroxide should be 1.8%. Belt scales feed the required amount of crushed wood particles into a continuous mixer (pos. 12), which also receives a certain amount of modifier solution. In the mixer, the components are thoroughly mixed, the moisture content of the press raw material should be 12%.

Then the press material enters the distribution funnel (pos.13), from where it enters the bunker (pos.14) of the finished press material. The bunker is the main buffer store to ensure the smooth operation of the plants. The bunker (pos. 14) is equipped with a screw dispenser (pos. 15), with the help of which the finished composition is loaded into the bunker of the extrusion unit (pos. 16), with the help of which the finished composition is fed into the extrusion head.

The channel of the extrusion unit (pos.17) is heated to a temperature of 1800C, the residence time in the heated part is 10 minutes, and in the unheated part it is also 10 minutes.

The pressed product (pos.18) is sent to the stage of cutting, culling and sorting, then it enters the stage of machining. After the control stage finished goods sent to the warehouse of finished products. Figure 6.1 Technology system production of a product in the form of a DP-BS skirting board from woodworking waste without the addition of binders by extrusion

Table 6.2 shows the calculation of the annual need for raw materials for the production of skirting boards. The estimated annual capacity of the line for the production of this type of product is 1 ton. Table 6.3 - Calculation of the need for raw materials and materials Type of raw materials Consumption rate (1 t), Cost of 1 kg of raw materials, rub. The amount of costs for 1 ton of products, thousand rubles. Pine sawdust 0.945 8 7.56 Industrial water 0.048 7 0.33 Hydrogen peroxide 0.007 80 0.56 Total: 8.45 The amount of costs for the purchase of raw materials per ton of finished production products will be 8.456 thousand rubles. Compared with the production of this type of product from WPC, which amounted to 47.65 thousand rubles. Thus, the production of skirting boards from DP-BS is economically viable. With the production of 50 tons / year, the savings in raw materials will amount to 1.96 million rubles.

Details you can cut 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 injection at home.

What we might need

For self-made plastic molding, we do not need any special tools or materials. 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 must be impregnated 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 you should buy it with the lowest viscosity - this will contribute to a better streamlining of the part. Of course, the results will be more accurate. There are a great many 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 certainty that sealant for cars, preferably red, is ideal for coating. With it, pouring plastic at home will be much easier.

Determining the casting material

To be honest, there are even more molding materials than silicone grades. Among them 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 casting substances:

  • The duration of their work.
  • Viscosity.

Regarding the first point, it indicates 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 the factory, then two minutes will be more than enough. Well, we, who do it at home, need at least five minutes. And if it so happened that suitable materials If you couldn’t get it, then it’s quite possible to replace them with a simple epoxy resin. Where to look for it? In auto shops or in stores for fans of aeromodelling. In addition, such resin is often found in ordinary hardware stores.

Making a cut shape

This one is ideal for pouring plastic with your own hands, because unusual types of resins can be poured into it. A little trick of this technique can be considered 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 form, we must apply a three-millimeter layer of sealant, after which we simply wait until the material hardens - usually it takes two hours. In this case, it is desirable to apply it with a brush. When applying the first layer, we must try to fill all the irregularities or voids with the material so that air bubbles do not subsequently form.

How is the casting process

First step.

We take the casting mold and thoroughly clean it - it should 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 for degassing of our casting mix. This can be explained by the fact that plastic molding 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, it is only necessary to manually remove them after pouring.

Fourth step.

Thoroughly mix all the necessary components and pour it into the template shape slowly, in 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 decrease significantly and become what we need.

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