RU2352597C1 - Biodegradable granular polyolefin blend and method of production - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: biodegradable granular polyolefin blend represents antimisting granules sized 2-8 mm of apparent bulk density 530-630 kg/m³, granule density less than 920-1300 kg/m³. Herewith melt flow index (MFI) of the parent polyolefin is MFI=2.5-25.0 g/10 minutes. Processing and relevant aid concentrate contains at least one biodegradable additive, thermostabilisers, antioxidants, lubricants, antistatic aids, pigments, fillers etc. The granular polymer blend is produced within a number of stages to ensure uniform distribution of all the aids in polyolefin. Four powder material flows are used. Three aid compositions are mixed with three parts of parent powder polyolefin in ratio 1:4, 1:3 and 1:2 respectively. Prepared concentrate mother stocks are supplied to the fourth combined mixer with residual part of polyolefin. If required, necessary liquid biodegradable additive. The blend is stirred and homogenised at 150-250°C.

EFFECT: underwater granulation and drying result in prepared antimisting and uncompressible sustained granular product characterised by good processing behaviour and performance attributes, easy-processed with the common equipment to make various products of controlled biodegradability.

3 cl, 5 tbl, 8 ex

Description

The invention relates to chemical technology and specifically relates to the production of polymeric biodegradable (biodegradable) materials, in particular to a biodegradable granular polyolefin composition, and can be used in the production of biodegradable products, including films, sheets and disposable tableware made by thermoforming from a sheet stock, injection molding and other methods.

Polymers, including polyolefins, are used in various products, including films, plates, fibers, foam materials, molded products, adhesives and many other special products. For applications in the field of packaging materials, agricultural materials, household goods and personal use products, polymers usually have a short cycle (less than 12 months) of use. For example, in food packaging, polymers play the role of a protective agent and are quickly released after the contents of the package are consumed.

Household products, such as detergent bottles and napkins, are thrown away after using the specified product.

Most of these plastic materials end up in solid waste streams, occupying rapidly disappearing and increasingly expensive terrestrial space.

In Russia alone in 2006, more than 1.1 million tons of film materials were produced, of which more than 70% accounted for polyolefin (polyethylene and polypropylene) films. These polymer products can decompose in natural conditions for up to 100 years or more, polluting the environment and having a harmful effect on the human body and all nature.

The use of various recycling processes (recycling of polymer waste into products) cannot completely solve the problem of the environment. The chemical nature of polymers (limited thermal stability) dramatically reduces the number of possible uses of recycling processes.

The reprocessing of even “pure” polymers results in degradation of the material and, consequently, in deteriorated mechanical properties of the product. Different grades of chemically similar plastics (for example, polyethylene of various molecular weights used as milk cartons and shopping bags) mixed after they are collected can cause processing problems, making the recovered material a poor quality product or unused.

The term biodegradable polymer has become an integral part of the green vocabulary. If earlier the efforts of researchers were aimed at creating materials resistant to environmental factors, today a new approach has arisen to the development of polymer materials. Its goal is to obtain polymers that retain performance only during the consumption period, and then undergo physicochemical and biological transformations under the influence of environmental factors and are easily included in the metabolism of natural biosystems.

The main direction in solving the environmental problem of landfills is the development of biodegradable polymers.

The ability of polymers to decompose and be absorbed by microorganisms depends on a number of structural characteristics. The most important are the chemical nature of the polymer, molecular weight, branching of the macrochain (the presence and nature of the side groups), the supramolecular structure, the presence of technological and target additives, etc.

Natural and synthetic polymers containing bonds that are easily hydrolyzed have a high biodegradability. The presence of substituents in the polymer chain often contributes to increased biodegradation. The latter also depends on the degree of substitution of the chain and the length of the sections between functional groups, and the flexibility of macromolecules.

An important factor that determines the resistance of the polymer to biodegradation is the size of its molecules. While monomers or oligomers can be more easily destroyed by microorganisms and serve as a source of carbon for them, polymers with a high molecular weight are more resistant to the action of microorganisms. Biodegradation of most polymers is usually initiated by processes of a non-biological nature (thermal decomposition, photooxidation, thermolysis, mechanical degradation, etc.). Mentioned degradation processes lead to a decrease in the molecular weight of the polymer. In this case, low molecular weight bioassimilable fragments arise having hydroxyl, carbonyl or carboxyl groups at the ends of the chain.

The world's leading scientists and firms offer to combat the accumulating "plastic garbage" in the following ways:

1) selection of special strains of microorganisms that can carry out the destruction of most polymers;

2) synthesis of biodegradable polymers using biotechnology methods.

One of the main areas is the development of the production of biopolymers derived from renewable natural resources. Company "Cargill-Dow" USA for the first time in the world mastered the production of polylactide (PLA) by fermentation of corn, with a capacity of 150,000 tons per year.

Polyhydroxyalkanates (PHA) are widely known - aliphatic polyesters, of which polyhydroxybutyrate (PHB) and polyhydroxyvalerate (PGV) are most known. They are made by bacterial fermentation from plant sugars, such as glucose. Polymers accumulate in bacterial cells, from where they need to learn how to extract the cheapest and safest way. PHA-based biodegradable polymers are close in their properties to the classical polyethylene polyethylene and polypropylene. They are easily decomposed by microorganisms, as well as plasma enzymes of animal tissues; these polymers are used not only as packaging material, the waste of which is destroyed by natural soil microflora to monomers, but also used in surgery and pharmacology.

The British company ICI has created new industrial polymer materials obtained using bacteria on natural substrates: sugar, ethanol, a mixture of gases (CO ₂ and H ₂ ).

The polymer synthesized by bacteria, poly-3-hydroxybutyrate, is not solvent resistant and has low heat resistance. Hydroxyvaleric acid is introduced into poly-3-hydroxybutyrate and a Biopol ™ polymer composition is obtained, which is completely destroyed by microorganisms within a few weeks (composting conditions are unknown);

3) synthesis of biodegradable polymer materials (PM) having a chemical structure similar to that of natural polymers

An example of such a synthesis is a biodegradable aliphatic polyester having a chemical structure similar to that of polyoxy-acetobutyrate cellulose.

Synthetically obtained polymers:

- an analogue of lignin (methoxyoxystyrene);

- biodegradable polyamide;

- a polyester collapsing by microorganisms, which includes lactic and finnylactic acid;

4) the use of natural polymers and special additives introduced into conventional large-tonnage technical plastics, in order to give them biodegradability properties.

This way of creating biodegradable composite polymers does not pretend to replace hydrocarbons with plant resources, but has its advantages. If it was possible to select the appropriate additives for bulk polymers, which, on the one hand, do not impair the performance properties of the products, but ensure biodegradation of plastics within an acceptable time period, the volumes of “plastic waste” would become much smaller. One should also take into account the fact that today, with all their great potential, biopolymers cannot replace the entire range of "traditional" polymers and are still quite expensive.

Among the “oldest” natural materials used in the packaging industry, films based on cellulose, chitin and chitosan, gelatin, polypeptides, etc. can be called. In recent years, interest in starch as one of the cheapest types of raw materials for organizing the industrial production of bioplastics has increased.

In particular, from RU 20263321, 01/27/1989 known polymer composition for molding products from the melt, including starch, having 5-30 wt. % water and a synthetic thermoplastic polymer, contains degraded starch, and as a synthetic thermoplastic polymer - a water-insoluble homo- or copolymer, in the following ratio, wt. %: water-insoluble homo- or copolymer of 0.1-90.

Examples of water-insoluble thermoplastic materials are polyolefins, such as polyethylene (PE), polyisobutylene, polypropylene (PP), vinyl polymers such as polyvinyl chloride (PVC), polyvinyl acetate (PVA), polystyrenes (PC), polyacrylonitriles (PAN); polyvinylcarbazoles (PVC); substantially water-insoluble polyacrylic acid esters or polymethacrylic acid esters; polyacetals (POM); polycondensates such as polyamides (PA), thermoplastic polyesters, polycarbonates, polyalkylene terephthalates; polyaryl ethers; thermoplastic polyimides; but also polyhydroxybutyrates (PHB) and high molecular weight, mainly water-insoluble polyoxyethylene oxides, such as ethylene oxide and propylene oxide polymers, as well as their copolymers.

It is desirable to degrade and granulate the starch before mixing it with a synthetic polymer, which is preferably in a granular state with a granule size equal to the granule size of the degraded starch. However, it is possible to process natural starch or pre-extruded granular or powdery starch together with powdery or granular plastic material in any desired mixture or sequence.

The starch in accordance with the invention may contain or may be mixed with additives, such as fillers, lubricants, plasticizers and / or coloring agents.

Additives can be introduced before or after the destructuring step, i.e. mix with hard granules of degraded starch. This mainly depends on the intended use of the degraded starch.

The described materials form thermoplastic melts when heated in a closed apparatus, i.e. subject to regulation of water content and pressure. Such melts can be processed in the same way as well-known thermoplastic materials, using, for example, injection molding, blow molding, extrusion and co-extrusion (extrusion of rods, pipes and films), direct compression for the production of known products. Products include bottles, chandeliers, pharmaceutical capsules, etc.

The known invention is mainly aimed at improving the dimensional stability of products made from such a composition. The need to create such compositions is associated with the use of starch in the polymer, providing biodegradability of the final product.

For this reason, the method of obtaining this composition is technically complicated and does not provide for the regulation of biodegradation of products from it.

Another biodegradable thermoplastic composition is known from RU 2174132, 06.23.2000, including cellulose diacetate containing acetate groups of 56.4-30 parts by weight, plasticizer - triacetin-30 parts by weight. and biodegradable filler - starch 10-50 wt.h. Moreover, it contains an additional biodegradable filler - hydrolytic lignin - 10-20 wt.h.

EFFECT: creation of a thermoformable composition based on highly filled cellulose diacetate, products from which are biologically destroyed under the influence of natural factors (soil microflora, water).

Filled compositions are processed at lower temperatures and lower shear deformations. Thermoformed products are obtained that are sufficiently durable under operating conditions, while, in the opinion of the inventors, productivity is increased and energy costs are reduced. However, specific information on the quality of products, on the timing and degree of their biodegradation is not provided.

A photodegradable composition based on polyolefins is known from RU 94023952, 05.27.1997, which contains a photosensitizing agent, alkyloxysilyl ferrocene, and a polyolefin — high or low density polyethylene, polypropylene, copolymers of ethylene with polypropylene, higher olefins, vinyl acetate and other mixtures and alloys thereof. The composition has limited use in the form of coextruded, laminating or laminated multilayer films, where the layers are made of the same or different polyolefins.

From JP 2007177083, July 12, 2007, a photodegradable polymer composition is known containing a mixture of polyethylene and polypropylene, calcium carbonate (20-50 wt.%) In combination with stearin (3-5 wt.%) And (1-3 wt.%) Stearic acid.

A foamable biodegradable composition is known from WO 2007052543, 05/10/2007, containing wax and / or polyolefin resin (polyethylene) in combination with polylactic acid.

From US 20050154097, July 14, 2005, a plastic product is known that degrades over time (degradable) through the use of a combination of degrading additives, such as metal salts (Fe, Ce, Co, Mn, Cu) and at least one sterically hindered amine. The composition may contain as a polymer a polyolefin, starch, another biopolymer; the composition may further comprise an aliphatic polyhydroxycarboxylic acid. The composition is not granular, data on the timing of its biodegradation are not indicated.

In WO 0139807, 07/07/2001, another degradable polymer composition is described, including a polyolefin, a metal carboxylate from a series including cobalt, cerium and iron, a degradation accelerating additive, in the form of 1-10 μm calcium carbonate fibers.

A multilayer film is known from US20060280923, December 14, 2006, one of the layers of which is made of a polyolefin containing 0.1-10 wt.% Of a degrading additive - a metal carboxylate and at least one aliphatic polyhydroxyxylcarboxylic acid.

The prior art shows that the use of various biodegradable and (or) photodegradable additives to polymers, including polyolefins, allows to obtain biodegradable compositions based on various non-biopolymers.

Nevertheless, the problem associated with the production of biodegradable polymeric materials is still relevant, due to the need to create such polymeric materials that would have sufficiently high performance properties for the period of storage and operation of polymeric materials and products from them and good biodegradability after the end of the life of these products (materials) based on them.

As noted above, in order to facilitate the storage, processing and transportation of such polymers (polymer compositions), it is also advisable to obtain them in granular form without compromising their biodegradability.

From RU 2263576, 03/13/2001, for example, is known to a method for granulating thermoplastic polymers, in particular thermoplastic polyolefins. According to the described method, the polymer powder obtained in the polymerization reactor is melted and homogenized in an extruder, then pressed through an extrusion nozzle and granulated. Before loading into the extruder, the polymer powder is subjected to heat treatment, heating it to a temperature of 5-30 K below the melting temperature of the polymer. In this case, the thermal energy necessary for heat treatment of the polymer powder is obtained due to the waste heat of the exothermic polymerization reaction. The invention improves the efficiency of homogenization of the material during granulation and productivity.

Only granular polymer is obtained by this method, into which, during further processing, various additives must be introduced, including biodegradable ones; the method basically solves the problem of energy saving.

A very important task, especially when obtaining various compositions based on polymers with various target additives necessary for the processing and operation of polymers and products from them, is to obtain granules of uniform composition, not dusting, and with good stable physicochemical characteristics. A well-known way to solve this problem is the use of "masterbatches" in the production of compositions.

In particular, from RU 2127286, 11/18/1996, a method for producing polyolefin-based polymer compositions is known. The compositions are characterized by increased resistance to thermal oxidative aging and can be used for the manufacture of pipes, profiles, films, sheets and other products. The method consists in preliminarily mixing a dithiocarbamate derivative and carbon black with a part of polyethylene or its copolymer with α-olefin, at a concentration of carbon black in polyethylene or its copolymer with α-olefin of 15-40 wt.%, Followed by mixing the resulting product with the remainder of polyethylene or its copolymer with α-olefin and a heat stabilizer in the following ratio of components, wt.%: heat stabilizer 0.01-0.5, dithiocarbamate derivative 0.005-0.5, carbon black 0.5-3.0, polyethylene or him copolymer with α-olefin - the rest. The proposed method allows to obtain a polymer composition with high resistance to thermal oxidative degradation at low concentrations of thermostabilizer.

In this way, a granular and biodegradable composition is not obtained.

From RU 2002124619, January 10, 2004, a method is known for producing masterbatches or concentrates of a mineral filler (mineral fillers) with a high content of inorganic substance or mineral filler (inorganic substances or mineral fillers), according to which the organic part of the filler concentrate, that is, a polymer mixture forming a binder and, if necessary, conventional additives, consists of 30-100% isotactic polypropylene with a melt flow rate (MFR) of greater than or equal to 200 g / 10 min (temperature 190 ° C, heat dressing 10 kg, die 1.05 mm) 0-70% of amorphous and / or crystalline polyolefins chosen from polypropylene, polyethylene and polymers or copolymers based on ethylenic monomers containing 2-6 carbon atoms used individually or as a mixture; 0-5% additives, such as thermal stabilizers, antioxidants, anti-UV components, dispersants, lubricants, dyes, plasticizers, antistatic agents, flame retardants, seeds, metal passivators such as copper passivators.

This compound may be in the form of aggregates or granules for the manufacture of industrial products by thermoforming or injection molding, in particular films, sheets, pipes, rods.

The claimed invention successfully selected a combination of partially known technologies for the production of granules, as well as the use of the principle of "masterbatches", to obtain biodegradable polymer materials. And this allowed us to obtain a granular polypropylene composition with controlled biodegradability and good stable performance properties during storage, processing and use (operation) of products from such a composition.

The technical task of the claimed group of the invention is to improve the manufacturability of the polymer composition in the process of its preparation, storage and processing, the ability to control the biodegradation of products from it while maintaining all the necessary consumer and technical properties of the composition and products for the entire specified period of their operation.

The technical problem is solved by the claimed group of the invention, which includes a biodegradable granular polyolefin composition and a method for its preparation. The technical problem is achieved by the biodegradable composition.

Biodegradable granular polyolefin composition for its subsequent processing into various products, in the form of non-dusting granules with a size of 2 mm to 8 mm, bulk bulk density of granules 530 ÷ 630 kg / m ³ , granule density 920 ÷ 1300 kg / m ³ made by melt extrusion obtained from a powder mixture composed of four parts, the first part of the concentrated masterbatch containing a smaller part of the initial powdery polyolefin of its total amount in the composition with a melt flow index of t 2.5 to 25 g / 10 min, the two subsequent masterbatches contain respectively at least one biodegradable additive that promotes the biodegradation of the product in contact with the biological medium, and concentrates of technological and target additives, as well as powdered polyolefin with the same melt flow rate and the remaining fourth part contains the remaining amount of powdered polyolefin in the amount of 26.315-88.925 wt.%, and the content of biodegradable (biodegradable) additives is 2-10 wt.% calculated on the whole composition.

So, the technical solution is achieved by a biodegradable granular polyolefin composition for its subsequent processing into various products, in the form of non-dusting granules with a size of 2 mm to 8 mm, bulk bulk density of granules 530-630 kg / m ³ , granule density less than 920-1300 kg / m ³ made by extruding a melt obtained from a powder mixture composed of four parts, and:

- the first part contains a smaller part of the powdered polyolefin from its total amount in the composition with a melt flow rate of 2.5 to 25 g / 10 min and a concentrate of target “regular” additives and with a ratio of 1: 4;

- the second part contains a powdered polyolefin with the same melt flow rate and a concentrate of biodegradable additives of 2-10 wt.% calculated on the whole composition with a ratio of components 1: 3.

- the third part contains a powdered polyolefin with the same MFR and a concentrate of technological additives 0.25-21.12 wt.% (t);

- the fourth part of the remaining amount of powdered polyolefin 23.315-88.925 wt.% supplements the entire composition to 100 wt.% (t).

As technological and target additives, it contains stabilizers of the polyolefin processing process, thermal stabilizers, antioxidants, lubricants and antistatic agents, antioxidant, biodegradable additive, pigments, fillers, emollients, optical brighteners, nucleators (nucleating agents), processing additive (additive) "Dynamer", for example, the brand FX 5911.

It is known that enlighteners, nucleators and processing additives improve the physicomechanical properties of finished products from polyolefins. However, in this case, these functional additives are also used to improve biodegradation:

1. Clarifiers and nucleators significantly affect the crystal structure of polyolefins, contribute to the formation of fine crystalline formations, which are more convenient for the destruction of the composition using microorganisms in the environment.

2. Processing additive FX 5911 is a triple copolymer of hexafluoropropylene with tetrafluoroethylene and vinylidene fluoride, which in addition to the active substance (triple copolymer) incorporates special finely dispersed fillers.

The processing aid changes the melt flow profile of the composition along the walls of the extruder barrel and all pipelines. In practice, it has been confirmed that the melt of the triple copolymer of hexafluoropropylene (melting point 110-126 ° C) does not dissolve in polyolefins and, when flowing through the pipes, fractionates and “envelops” all the internal walls of the cylinder of pipelines and channels of the forming tool.

This provides:

- a sharp decrease in melt overheating in all heated walls of the extruder cylinder, pipelines and the forming head, and thus biodegradable additives on an organic basis are protected from premature thermal decomposition;

- lowering the temperature of the melt by 15-20 ° C without a significant increase in back pressure in the forming head;

- reduction in the number of deposits and the cleaning time of the head from carbon deposits;

- reducing the time to replace the color of the composition;

- homogeneous distribution of additives in the final product.

The technical task is also achieved by the method of preparation of this composition according to the invention. A method of obtaining a biodegradable granular polyolefin composition according to the invention is as follows. First, three masterbatches are prepared in the form of concentrates by dry mixing part of the total amount (content) in the composition of the powdered polyolefin with technological and target additives, including at least one biodegradable additive, with a ratio of polyolefin and additives in the masterbatch, respectively 1: 4 , 1: 3 and 1: 2, while the first masterbatch is prepared in a batch mixer for 85-95 minutes, the second and third masterbatches are obtained in a continuous mixer, mixing for 3-4 minutes, then rovodyat dry mixing the obtained masterbatch with the remaining amount of the powdered polyolefin continuous mixer for 3-4 min, and stirring was carried out further homogenizing the components of the composition in the melt and pelletizing the composition in a 2-screw granulator at a temperature of 150 to 250 ° C.

Thus, the technical solution of the problem is also achieved by the method of producing a biodegradable granular polyolefin composition for its subsequent processing into various products, characterized in that it includes the preparation of concentrates of technological and target additives by mixing three masterbatch dry concentrates of mixtures of various groups of additives with powdered polyolefin in different mixers for a different period of time and a different ratio of components, followed by dry mixing we eat in a continuous mixer all the masterbatches with the addition of the remaining part of the powdered polyolefin and further mixing, homogenizing the components of the mixture in the melt and granulating the composition in a 2-screw extruder at a temperature of from 150 to 250 ° C.

So, the proposed composition according to the invention may contain various stabilizers, an antistatic agent, an initiator of the formation of nuclei, a pigment (dye), an inorganic filler, and other target and technological additives.

When a phenolic type thermal stabilizer is introduced into the olefin polymer composition of the present invention, a molded article can be obtained with improved thermal stability and transparency, therefore, the introduction of a phenolic type stabilizer is preferable. In the case of the introduction of both phenolic type stabilizers and based on organic phosphite in the proposed composition, it is possible to obtain a molded product with significantly improved thermal stability and transparency, and therefore their introduction is preferable.

The use of a combination comprising a phenolic type stabilizer and / or an organic phosphite or phosphonite stabilizer and a metal salt of a higher aliphatic acid is particularly preferred.

In particular, such phenolic antioxidants are used, for example, the Irganox type [Irganox 1010, Irganox 1076 - 3- (3,5-di-tert-butyl-4-hydroxyphenyl), etc.]; organic phosphites (alkofen phosphite, distearylpentaerythritol diphosphite, etc.) and organic phosphonites; in the amount traditionally used for them, in particular, in amounts of 0.01-2.0 wt.%.

Specific examples of phenolic stabilizers include, but are not limited to:

2,6-di-tert-butyl-4-methylphenol,

2,6-di-tert-butyl-4-ethylphenol,

2,6-dicyclohexyl-4-methylphenol,

2,6-diisopropyl-4-ethylphenol,

2,6-di-tert-amyl-4-methylphenol,

2,6-di-tert-octyl-4-n-propylphenol,

2,6-dicyclohexyl-4-n-octylphenol,

2-isopropyl-4-methyl-6-tert-butylphenol,

2-tert-butyl-2-ethyl-6-tert-octylphenol,

2-isobutyl-4-ethyl-5-tert-hexylphenol and others.

These phenolic stabilizers are used both in pure form and in combination with each other in amounts traditionally used, in particular in amounts from 0.01 to 1.0 wt.%.

Specific examples of stabilizers based on organic phosphites include:

Thioctylphosphite,

Triarylphosphite,

Tristridecylphosphite,

Trisisodecylphosphite

Phenyl diisooctyl phosphite,

Phenyl diisodecyl phosphite,

Phenyldi (tridecyl) phosphite,

Diphenylisooctylphosphite,

Diphenyl isodecyl phosphite,

Diphenyltricedylphosphite,

Triphenylphosphite,

Tri (nonylphenyl) phosphite,

Tris (2,4-di-tert-butylphenyl) phosphite,

Tris (butoxyethyl) phosphite,

Tetra (tridecyl) -4,4′-butylidenebis (3-methyl-6-tert-butylphenol) diphosphite.

Of these compounds, it is preferable to use tris (2,4-di-tert-butylphenyl) phosphite, tris (nonylphenyl) phosphite and tetrakis (2,4-di-tert-butylphenyl) -4,4-biphenylene diphosphite; from organic phosphonites, for example tetrakis (2,4-di-tert-butylphenyl) -4,4 ^, -phenylene diphosphonite.

These stabilizers based on organic phosphites or phosphonites are used individually and in combination with each other in conventionally used amounts, for example, 0.01-0.5 wt.%.

As other technological and targeted additives biodegradable granular composition according to the invention contains:

- stabilizers of the processing of polyolefins, such as salts of metals and carboxylic (higher aliphatic) acids in amounts traditionally used for them, for example, from 0.01 to 1.0 wt.%.

Examples of metal salts of higher aliphatic acid include alkali metal salts, alkaline earth metal salts and other metal salts of saturated or unsaturated carboxylic acids containing from 12 to 40 carbon atoms (C _12-40 saturated or unsaturated carboxylic acids mentioned above may contain substituents, e.g. hydroxyl groups).

Examples of C _12-40 saturated or unsaturated carboxylic acids include stearic, oleic, lauric, caprioic, arachidonic, palmitic, behenic, 12-hydroxystearic and montanoic acids, and examples of metals that can form salts when reacted with these higher aliphatic acids are alkaline earth metals, for example magnesium, calcium and barium; alkali metals such as sodium, potassium and lithium and other metals, excluding heavy metals.

Specific examples of the metal salts of higher aliphatic acids include: magnesium stearate, magnesium laurate, magnesium palmitate, calcium stearate, calcium oleate, calcium laurate, barium stearate, barium oleate, barium laurate, arachidonic acid barium salt, behenic acid barium salt, zinc stearate zinc oleate, zinc laurate, lithium stearate, sodium stearate, sodium palmitate, sodium laurate, potassium stearate, potassium laurate, calcium 12-hydroxystearate.

Of these metal salts of higher aliphatic acids, it is particularly preferable to use zinc and calcium salts of saturated aliphatic acids containing from 12 to 35 carbon atoms.

These metal salts of higher aliphatic acids can be used in pure form or in combination with each other.

Other targeted additives are:

- substances that reduce friction during the extrusion process (fatty acid amides, for example oleic acid amide, for example, Finawax 0 brand, in an amount of, for example, 0.05-2.0 wt.%;

- lubricants and antistatic substances (wax, paraffin oil, glyceryl monostearate and others in an amount of 0.05-0.1 wt.%;

- modifiers of molecular weight and rheological properties, for example peroxides;

- various fillers, for example carbon black, natural calcium carbonates, etc., pigments, dyes, flame retardants, nucleating agents and other additives traditionally used in the processing of polyolefins.

As biodegradable additives, the composition according to the invention contains various biodegradable additives that promote biodegradation of products made of polyolefins (films, injection molded and molded various products) upon contact with the external biosphere (under the influence of soil biota, sewage and river water, water sediment, manure or vermicompost and liquid extracts of it, under the influence of various microorganisms). For example, various special additives can be used as such additives in the compositions according to the invention, which regulate the degree and time (time) of degradation and subsequent decomposition of products from polymeric materials under the influence of biological environmental factors, as well as promoting accelerated photodegradation of polymers.

Such additives, in particular, are starches, including granular starch, crude starch, starch ethers and polyoxyalkylene glycol, chitosan, chitins, polylactides, microcellulose fiber, monocrystalline cellulose, cellulose acetate, lignin and its derivatives, and other polymers decompositions, salts of carboxylic acids, for example cobalt stearates (metal carboxylates), aliphatic polyoxycarboxylic acids (citric, glyceric, malic, lactic acid and its production n), in combination, possibly with agents that accelerate oxidation (an oxidizing agent acting as a catalyst for biodegradation), various combinations of them, for example, a combination of metal carboxylate (Fe, Co, Cu, Al, Zn, etc.) and aliphatic polyhydroxycarboxylic acid ( for example, citric, lactic acid) and a degradation regulator (calcium oxide); and they also use imported brands of ECM, PDQ-H, UV-H additives, Bio-Batch ™ additive and others (see, for example, the journal Plastics masses 2001, No. 2, pp. 42-46, "Polymer materials" No. 11, p. 8-12; No. 12, p. 22-27, 2005); US20050154097, July 14, 2005; WO 2007048831).

Additives can be introduced into the polymer both on a carrier, for example, on an ethylene copolymer and linear high pressure polyethylene (LLDPE), a copolymer of ethylene with vinyl acetate, polypropylene, etc., and without it.

As a stabilizer (regulator) of the biodegradation process, calcium oxide is used, in particular. When metal carboxylates (Co, Fe, etc.) are used as, for example, biodegradable additives, metal carboxylate (for example, cobalt stearate) stimulates the photodestruction of the polymer, and aliphatic acid (for example, citric) is “responsible” for the chemical decomposition of PM in the compost .

One of the descriptions of the mechanism of occurrence and course of biodegradation with the help of additives may be the following.

Oxidative processes due to the presence of additives lead to the breaking of long polymer chains and a corresponding decrease in the molecular weight of the polymer. The film quickly becomes brittle and breaks up into small flakes. As the length of the macromolecules decreases, oxygen is able to connect with carbon to form CO ₂ . In this case, the molecular weight of the base polymer continues to decrease sharply and a biofilm containing various microorganisms is formed on the macromolecules. Colonies of microorganisms from the environment “absorb” the carbon and hydrogen contained in the oxidized PM, and ultimately the PM turns into H ₂ O, CO ₂ and biomass.

In practice, it is important to have such biodegradable additives so that the decomposition process proceeds both in aerobic (in the presence of atmospheric oxygen - with the formation of CO ₂ and water), and in anaerobic (in the absence of oxygen in the atmosphere with the formation of CO ₂ , methane and water.

Finally, an important condition for creating a composite biodegradable material is to ensure all the technical properties of the product necessary for the consumer for the entire specified period of its operation. And for these purposes, the traditionally used various technological and targeted additives necessary in the process of obtaining, processing and operating this composition according to the invention are introduced into the composition. The concept of biodegradable composition in the context of the claimed invention may include essentially simultaneously photodegradation of the polymer, chemical degradation (destruction) of the polymer (and the product thereof).

Various polyolefins are used as polyolefins in the invention, in particular polyethylene, polypropylene and copolymers of ethylene and polypropylene with MFR = 2.5-25.0 g / 10 min.

The following are, in particular, examples of the preparation of a composition according to the invention, illustrating (but not limiting) the general method for preparing a composition, also claimed as an invention from the claimed group.

As an example, the claimed invention shows biodegradable polypropylene compositions based on two serial grades of polyethylene "KAPLEN" (TU 2211-015-00203521-99).

The choice as an example of a polypropylene biodegradable composition is due to the fact that:

1. These compositions are processed at higher temperatures and shear stresses than other polyolefins.

2. Polypropylene is widely used in the manufacture of disposable tableware and disposable cutlery.

3. Practice has shown that the technological process for the production of biodegradable LDPE, HDPE, linear polyethylene, polypropylene according to this invention is the same and universal.

So, below are examples of the production of biodegradable compositions based on powdered polypropylene with MFR = 3.0 and 25.0 g / 10 min:

1. Compositions with MFR = 3.0 g / 10 min are used for sheet extrusion and subsequent thermoforming of disposable tableware (plates, thin-walled glasses, containers, etc.)

Compositions with PTR = 25.0 g / 10 min are used for injection molding of disposable tableware - cutlery (spoons, forks, knives), disposable containers, packaging, etc.

2. The composition of all the following examples includes targeted, technological (regular) additives in an amount of 0.465 wt%, for example:

- stabilizers of the processing process (a mixture of "Irganox B 215" and "Irgonox 1075" - phenolic type antioxidant) in an amount of 0.09 wt.%;

- antioxidant - "Irganox 1010" - 0.025 wt.%;

- antioxidant (calcium stearate) - 0.05 wt.%;

- a structuring additive - a Hiperform nucleator of the HPN-20E brand (or 68L) or a Milad NX 8000 enlightener or a mixture thereof - 0.2 wt.%;

- processing additive brand "Dynamer" FX 5911-0,05 wt.%;

- antistatic GMS or Armostat 1000-0.05 wt.%.

In addition to these "regular" additives, the composition of the composition includes additives, the composition and percentage of which may vary:

3. Biodegradable components.

4. Other possible (additional) target and technological additives, which vary depending on the specific conditions of production of the final product and methods of waste disposal.

Currently, there is no scientifically based approach to the selection of biodegradable compositions, however, in practice it has been noted that the supramolecular structure of synthetic polymers is a significant factor affecting biodegradation. The compact arrangement of structural fragments of semi-crystalline and crystalline polymers limits their swelling in water and other natural environments and prevents the penetration of enzymes into the polymer matrix. This complicates the effect of enzymes not only on the main carbon chain of polymers, but also on biodegradable parts of the chain. The amorphous part of the polymer is always less resistant to biodegradation than the crystalline one. In this regard, it is important to set such additives in the composition that would contribute not only to the optimal biodegradation of products, but also allow the production of products with the desired consumer properties while minimizing the cost of their production.

For example, in the production of disposable thermoformed dishes from sheet materials, up to 50% of sheet waste is generated with a cut from finished products. These wastes are crushed and added to raw materials. It was of practical interest to study the repeated extrusion of the same raw material (up to 5 times) and to determine the change in properties during repeated (5 times) and single processing of biodegradable polypropylene compositions.

Studies were carried out on the physicomechanical properties of the polypropylene composition with biodegradable additives after the 1st and 5th granulation.

For the 1st extrusion and granulation, mixtures of biodegradable additives and powdered polypropylene were prepared (with additives to polypropylene in accordance with standard formulations according to the technological regulations for the industrial granulation process).

The temperature conditions at the granulation plant, for example, were as follows:

Table 4 Brand KAPLEN PP 01030 Zones one 2 3 four Temperature ° С 190 210 220 210 Brand KAPLEN PP 01250 Zones one 2 3 four Temperature ° С 160 170 180 170

After the first granulation from the composition of polypropylene with biodegradable additives, laboratory samples were made of film samples and injection standard samples.

Physico-mechanical tests of the composition were carried out in accordance with the standards of GOST and ASTM.

The remaining granulate after the 1st extrusion was granulated again, repeating this procedure 4 more times; thus, the granular composition was subjected to 5-fold processing.

After each subsequent granulation (regranulation), the film and injection standard samples were produced again and the physical and mechanical properties of the samples were tested again.

A series of experiments showed that 5-fold extrusion does not cause significant changes in the properties of the composition compared with the properties of polypropylene without biodegradable additives (see table 5).

Table 5 Test Name Test method documentation Standards for technical specifications on PP without biodegradable additives Biodegradable Samples Granulate based on PP 01030, after Injection samples based on PP 01250, after PP film based on PP 01030, after PP 01030 PP 01250 1 ext. 5 ext. 1 ext. 5 ext. 1 ext. 5 ext. 1. Determination of melt flow rate, g / 10 min GOST 11645 2.9-3.5 23-27 3,7 4,5 27,2 27.9 - - 2. Determination of tensile yield strength, MPa GOST 11262 34 - - 35.0 34.7 - - 3. Determination of elongation at yield strength,% GOST 11262 10 - - 32 31 - - 4. Determination of the softening temperature by Wick, ° C GOST 15088 150-157 - - 154.9 153.9 - - 5. Determination of impact strength Izod notched, J \ m ² GOST 19109 20-150 - - 62.9 51.7 - - 6. Determination of the modulus of elasticity in bending, MPa GOST 9550 1000-1700 - - 1628 1592 - - 7. Rockwell hardness test, R ASTM
D 785 70-97 - - 86 81 - - 8. Determination of the temperature of thermal deformation at a load of 0.46 N / mm ² , ° C ASTM
D 648 70-96 - - 88.4 85,2 - - 9. Determination of film thickness, microns GOST 17035 - - - - 50, 100, 500 50, 100, 500 10. Determination of tensile strength, MPa GOST 14236 19 - - - - 29.0 26.5 11. Determination of elongation at break of the film,% GOST 14236 200 - - - - 1090 930 12. Linear shrinkage in the form,% GOST 18616 1.4-2.0 - - 1.1-2.0 - -

The technical solution of the problem of creating a biodegradable polyolefin composition is also achieved by the method of producing a granular product with the maximum possible uniform distribution of all functional additives in the granulate.

It is known that manufacturers of biodegradable additives offer to use them as superconcentrates (masterbatch) in a base polymer by mixing them before extrusion (or injection molding). Practice has shown that the uneven distribution of biodegradable additives in the final product leads to a significant heterogeneity of its decomposition in natural environments.

To prepare a biodegradable granular polypropylene composition according to the claimed invention, a multistage system for mixing components is used, followed by granulation using various equipment used to prepare mixtures (mixing, dispersing) of polymers with various additives, both powdered, solid and liquid, as well as various equipment used for subsequent extrusion of the melt and granulation, depending on the nature of the products (pl canes, sheets, injection products, fibers, technical, household, medical products, toys, products intended for contact with food products).

To obtain a granular biodegradable composition, it is proposed to use masterbatches (additive concentrates) in order to achieve a high-quality distribution of all additives in the base powder polyolefin due to the following mixing technology:

- I stage dry mixing of individual groups of additives in separate mixers;

- II stage of dry mixing of all components of the composition in one continuous mixer;

- III stage mixing additives in the molten polypropylene;

- averaging granules of the batch of the product in silos and packing granules in a transport container.

The following are examples of biodegradable granular polyolefin compositions according to the invention and methods for its preparation. These examples illustrate the invention, but do not limit it. Biodegradation occurs under the influence of natural conditions: solar radiation, heat and microorganisms (fungi, bacteria, algae, etc.) under aerobic and anaerobic conditions

Specific examples are given using polypropylene as the polyolefin.

EXAMPLE 1

To obtain a granular biodegradable composition based on the base brand of polypropylene with MFR = 3.0 g / min (for example, for sheet extrusion and subsequent thermoforming of disposable tableware), the following composition is used per 100 tons of composition (100 wt.%):

2.1 "Regular" additives mentioned above - 0.485 wt.% (T);

2.2 Biodegradable additives:

- cobalt stearate - 1.5 wt.% (t);

- citric acid - 0.55 wt.% (t).

2.3. Dye superconcentrate - 3 wt.% (T)

For the preparation of masterbatches based on 3 groups of additives (according to 2.1-2.3), polypropylene powder is used in ratios of 1: 4, respectively; 1: 3; and 1: 2 (see below).

3.1 “Regular” additives - 0.485 wt.% (T) are mixed with the first part (1.86 t) of polypropylene - with a ratio of components 1: 4, in two periodically alternating planetary-conical mixers. Mixing time - 85-90 minutes. During the unloading of the first mixer, the next portion of the masterbatch is prepared in the second mixer.

3.2 Biodegradable additives - 2.05 wt.% (T) are mixed with the second part of the powdered polypropylene (6.15 wt.% (T)) by combining two streams of materials and feeding them into a continuous high-performance mixer (component ratio 1: 3). Mixing time (residence time of the mixture in the mixer) is 3-4 minutes.

3.3 Dye superconcentrate - 3 wt.% (T) (or other additional target and technological additives) are mixed by simultaneously feeding two streams of materials (dye superconcentrate and polypropylene powder) into a continuous high-performance mixer, providing high-quality mixing of components in a ratio of 1: 2 for 3-4 minutes

The dry mixes of additive concentrates prepared in this way enter the second stage of dry mixing.

4. The second stage of dry mixing of all individual groups of masterbatch mixtures (according to Clauses 3.1, 3.2, and 3.3) is carried out in a continuous mixer, where the fourth (last) part of the polypropylene powder is supplied - 80.475 wt.% (T). If necessary, a liquid-phase additive, for example, biodegradable, can be supplied to the same mixer. The mixing time of all components of the composition (residence time in a continuous mixer) is 3-4 minutes.

All of the above stages of dry mixing are performed without heating the composition.

Thus, in EXAMPLE 94.485 wt.% (T) of powdered polypropylene used throughout the composition and taken as 100% is distributed as follows:

- The first masterbatch of “regular” additives consumes 1,860 tons of polypropylene powder or 2,325 wt.% Of the total polypropylene powder (of the total amount of polypropylene powder in the composition). This number of components is constant for all examples used in this application.

- For the second masterbatch of biodegradable additives, different amounts of powdered polypropylene are consumed depending on the percentage of additives for this purpose, although the ratio of the amounts of biodegradable additives and powdered polypropylene is constant for all of the following examples (1: 3). In this example, 6.150 tons of powdered polypropylene or 8.2 wt.% (Of the total amount of powdered polypropylene per composition) are used for these purposes.

- The third masterbatch - superconcentrates of dyes (or other additives) consumes 9.0 wt.% Powdered polypropylene (from the whole composition). With a constant ratio of components in this mixture (1: 2), the absolute value of the consumed powdered polypropylene will also vary depending on the amount of added additives. The range of change in the percentage of input additives is wide enough (see below).

- The fourth (remaining) part of the powdered polypropylene of 80.475 tons enters the total mixture of all additives in the second stage of mixing before extrusion of the melt composition. This part is also unstable, and varies depending on the size of specific additives in the composition. In this example, at this stage, 80.475% by weight of polypropylene powder is used (of the total amount of polypropylene powder per composition).

The mixture prepared in this way enters the hopper of a special 2-screw extruder with special mixing cams. The cylinder of the extruder is heated to a temperature of 210 to 250 ° C. Since the complex geometry of the screws is used, when the composition moves from the charging funnel to the granulating head, the melt is intensively mixed and a good uniform distribution of the components of all additives in the finished product is achieved - granulate. Underwater granulation, water separation, sorting and drying of granules complete the process of manufacturing a biodegradable composition based on polypropylene.

After separating the water from the granules, they are dried and the batches of polymer are averaged in special silos (for 1.2-2 hours), from where the product is fed to packaging: it is packed in 25 kg plastic bags or another method of product shipment is used.

Get non-dusting granules with a size of 2-8 mm, a bulk density of granules up to 530 kg / m ³ , a density of granules up to 920 kg / m ³ .

The process of processing this polypropylene composition into disposable tableware occurs on conventional processing equipment without significant changes in its parameters.

Biodegradation of products from such a composition begins on average after 30 days, depending on the conditions of landfills or industrial composting.

EXAMPLE 2

A granular polypropylene biodegradable composition is obtained similarly to EXAMPLE 1, but instead of KAPLEN 01030 polypropylene (MFR = 3 g / 10 min), KAPLEN 01250 polypropylene with MFR 25 g / 10 min is used. Such a composition is used for casting various disposable products.

EXAMPLE 3

To obtain a biodegradable composition based on base grade 01250 (for injection molding), the following composition is used per 100 tons of the composition (100 wt.%):

The composition of the masterbatch:

- “regular” additives - 0.465 wt.% (T) are mixed with the first part (1.860 wt.%) Of polypropylene powder;

- biodegradable additive - 2 wt.% (t), consisting of a mixture of:

cobalt stearate 1.7% (t);

sodium citrate - 0.3% (t).

mixes up with the second part (6 wt.%) of powdered polypropylene.

Other targeted and technological additives:

- pigment oxide of iron - 0.12 wt.% (t);

- glycyrin monostearate (glycyrolmonostearate) in an amount of 1 wt.% (t);

- special grade of chalk (CaCO ₃ ) - 20 wt.% (t)

mixed with the third part of the powdered polypropylene - 42,240 wt.% (t).

The fourth (last) part of the polypropylene powder - 26.315 wt.% Enters the second stage of dry mixing of all additives.

Further operations for the manufacture of granulate produce similarly to EXAMPLE 1.

Get non-dusting granules with a size of 2-8 mm, a bulk density of granules up to 630 kg / m ³ , a density of granules up to 1300 kg / m ³ . The biodegradation of products made from such a composition begins on average in 20 days, depending on the conditions of the landfill.

EXAMPLE 4

To obtain a biodegradable composition based on KAPLEN 01030 polypropylene (PTR = 3 g / 10 min), the following composition per 100 t of composition (100 wt.%) Is used for sheet extrusion:

Состав добавок:

The composition of the additives:

- “regular” additives mentioned above - 0.465 wt.% (T);

- biodegradable additive - 9.6 wt.% (t), including:

cobalt stearate - 6 wt.% (t);

citric acid - 3 wt.% (t);

calcium oxide - 0.6 wt.% (t) - a regulator (stabilizer) of the biodegradation process. Calcium stearate and citric acid are introduced into the carrier (binder) of a copolymer of ethylene with vinyl acetate.

- dye superconcentrate - 3 wt.% (t).

The composition of the masterbatch:

- “regular” additives - 0.465 wt.% (T) are mixed with 1.860 wt.% (T) of powdered polypropylene;

- biodegradable additive - 9.6 wt.% (t) is mixed with the second part of the powdered polypropylene - 28.8 wt.% (t);

- dye superconcentrate - 3 wt.% (t) is mixed with the third part of the polypropylene powder - 6 wt.% (t);

- the fourth (last) part of the polypropylene powder - 50.275 wt.% enters the second stage of dry mixing of all components.

The second stage of dry mixing of all components of the composition and further operations for the manufacture of granules produce similarly to EXAMPLE 1.

Get non-dusting granules with a size of 2-8 mm, a bulk density of granules up to 550 kg / m ³ , a density of granules up to 950 kg / m ³ . The biodegradation of products made from such a composition begins on average in 20 days, depending on the conditions of the landfill.

EXAMPLE 5

Biodegradable composition for the extrusion of films and thin sheets (up to 1 mm thick) for thermoforming based on polypropylene with PTR = 3 g / 10 min has the following composition:

Состав маточных смесей:

The composition of the masterbatch:

“Regular” additives - 0.465 wt.% (T) are mixed with the first part of the powdered polypropylene - 1.860 wt.% (T);

biodegradable additive - 2 wt.% (t) is mixed with the second part of the powdered polypropylene - 6 wt.% (t).

As a biodegradable additive, an ECM biodegradable additive (WO 2007048831, 05/03/2007, for example) is used, containing, for example, fibers (calagen, elastin), proteins (fibropectin, laminin) and, for example, molecules of one or more glycosaminoglycan , glycoprotein, and / or proteoglycans; or, for example, PDQ-H additive or, for example, Bio-Batch ™ additive. It is possible to use these additives also on a polymeric carrier - linear polyethylene (LLDPE). Biodegradable additive can be used in combination with polysaccharides (cellulose and its derivatives; alginates, chitosan, pectin), as well as in combination with polylactides and other biodegradable materials;

structuring additive - talc of the Jetfin 1CA brand in an amount of 0.25 wt.% (t) is mixed with the third part of the polypropylene powder - 0.5 wt.% (t);

the fourth (last) part of the polypropylene powder - 88, 925 wt.% (t) enters the second stage of dry mixing of all components.

The second stage of dry mixing of all components of the composition and further operations for the manufacture of granules produce similarly to EXAMPLE 1.

Get non-dusting granules with a size of 2-8 mm, a bulk density of granules up to 530 kg / m ³ , a density of granules up to 920 kg / m ³ . The biodegradation of products made from such a composition begins on average after 30 days, depending on the conditions of the landfill.

EXAMPLE 6

The biodegradable composition for the extrusion of films and thick sheets (more than 1 mm thick) for thermoforming on the basis of polypropylene with PTR = 3 g / 10 min has the following composition:

Состав маточных смесей:

The composition of the masterbatch:

“Regular” additives - 0.465 wt.% (T) are mixed with the first part of the powdered polypropylene - 1.860 wt.% (T);

the biodegradable additive from EXAMPLE 5 in an amount of 5 wt.% (t) is mixed with the second part of the powdered polypropylene - 15 wt.% (t);

structuring additive - talc of the brand Jetfin 1CA in an amount of 0.5 wt.% (t) is mixed with the third part of the powdered polypropylene - 1.0 wt.% (t);

the fourth (last) part of the polypropylene powder - 76.175 wt.% (t) enters the second stage of dry mixing of all components.

Further operations for the production of biodegradable polypropylene are carried out similarly to EXAMPLE 1 (5).

Get non-dusting granules with a size of 2-8 mm, a bulk density of granules up to 550 kg / m ³ , a density of granules up to 950 kg / m ³ .

The biodegradation of products made from such a composition begins on average in 20 days, depending on the conditions of the landfill.

EXAMPLE 7

The biodegradable composition based on polypropylene with PTR = 25 g / 10 min for injection molding thin-walled (up to 1 mm) products of disposable tableware (spoons, forks, knives, containers and other products) has the following composition:

- powdered polypropylene 01250 -94.035 wt.% (t);

- the total number of all technological and target additives is 5.965 wt.% (t), as in EXAMPLE 5 and 6.

The mixture of all target and technological additives, as well as the entire process of production of biodegradable granulate, is similar to EXAMPLE 1 (6).

EXAMPLE 8

Biodegradable composition based on polypropylene with PTR = 25 g / 10 min for injection molding of thick-walled (with a wall thickness of more than 1 mm) disposable products has the following composition:

Состав маточных смесей:

The composition of the masterbatch:

“Regular” additives - 0.465 wt.% (T) are mixed with the first part of the powdered polypropylene - 1.860 wt.% (T);

the biodegradable additive according to EXAMPLES 6 and 7 in an amount of 10 wt.% (t) is mixed with the second part of the powdered polypropylene - 30 wt.% (t);

structuring additive - talc of the brand Jetfin 1CA in an amount of 0.5 wt.% (t) is mixed with the third part of the powdered polypropylene - 1.0 wt.% (t). The mixture of all target and technological additives, as well as the entire process of production of biodegradable granulate, is similar to EXAMPLES 1 (6, 7).

Get non-dusting granules with a size of 2-8 mm, a bulk density of granules up to 570 kg / m ³ , a density of granules up to 980 kg / m ³ .

The biodegradation of products made from such a composition begins on average in 20-30 days, depending on the conditions of the landfill.

The following are examples to illustrate the specific parameters of the process of processing biodegradable polypropylene compositions according to the invention into laboratory samples of films and standard injection molds for conducting physical, mechanical and biological tests.

To produce laboratory samples of films with a width of 150 mm and a thickness of 50 to 500 μm, an extrusion line was used with a standard screw 32 mm in diameter and 25 D.

Temperature conditions for the extrusion of polypropylene grade PP 01030 (PTR 3 g / 10 min) with biodegradable additives:

Table 1 Zones one 2 3 four 5 6 7 8 Head Temperature ° С 180 200 210 220 220 220 220 215 205

The manufacture of standard injection molds (bars, blades, plates) from polypropylene of two grades and additives was carried out on injection molding machines.

The temperature conditions on the injection machine for polypropylene are given in table 2.

table 2 Brands PP Zones one 2 3 Note 01030 Temperature ° С 205 200 195 01250 180 175 170

Form temperature ~ 65 ° С.

Samples of injection disposable cutlery (coffee spoons) made of PP 01250 polypropylene grade with biodegradable additives were produced on DEMAG-D85 thermoplastics under factory conditions under the following conditions (Table 3).

Table 3 Heating zones one 2 3 Nozzle Temperature ° С 195 210 220 230

The temperature of the 8-nest hot runner mold: 20-30 ° C.

Cycle time: 14 sec.

The processing of the polypropylene composition with biodegradable additives was carried out practically under normal conditions, both in laboratory and industrial equipment for thermoforming from a sheet of disposable tableware and injection molding. However, depending on the type of biodegradable additives used and the thickness of the products (samples), the natural color of polypropylene may change from a transparent white to purple.

Biological tests have shown that the rate of biodegradation of samples depends on:

- the activity of the biodestructor (microorganisms) in the natural environment (landfills, industrial composting, etc.); strains of microorganisms of lower fungi (Aspergillus caespittosuns) and higher fungi (Panus tigrinus) most actively grow (biodegradable polypropylene), using composite additives, for example, ECM, PDQ-H, Bio, for their reproduction (growth) as a source of carbon and energy -Batch ™.

- the composition of the natural environment in which biodegradation of the samples occurs;

- temperature, pH of the medium;

- the presence of sunlight - ultraviolet and infrared radiation;

- aerobic or anaerobic (and other) decomposition conditions;

- the type of biodegradable additive used, etc.

The duration and conditions of the winter period affect the decomposition of polypropylene, as the vital activity of microorganisms in this period of time almost completely ceases.

The best biodegradation results for polypropylene were obtained on films with a thickness of 50 μm. Weight loss (taking into account winter time) for 12 months was ~ 50%.

Over the same period of time, the weight loss of single-use plates was 10%, and injection molds 3%.

The examples and results of a comprehensive study of various compositions based on polypropylene showed that:

1. Products from the materials proposed for this application retain all the basic physical, mechanical and technological properties when processed into products using conventional extrusion, thermoforming industrial equipment and injection molding machines in the production of disposable tableware and cutlery.

2. Under certain conditions, the onset of biodegradation is ensured within 20-30 days. Based on the conducted experimental studies in independent specialized laboratories during the year in different natural environments and taking into account the expert evaluation of leading experts in this field, we can conclude that the decomposition of polymer products (for example, disposable tableware and cutlery) made from a composition according to this application can be achieved within 2-10 years instead of 100 or more years.

Thus, it can be argued that the biodegradable granular polyolefin composition with a specific granule size, ensuring its manufacturability in processing on various equipment and the most favorable conditions under different storage conditions in combination with such properties as bulk density of granules, density of granules, and obtained using various biodegradable additives, providing regulation of the terms of its decomposition under the various conditions indicated above, as a whole allows on its basis Ove to receive various products that retain good properties during their operation and ensure, on the other hand, their quick disposal after the end of their operation. The invention thereby solves an important environmental problem in protecting the environment.

Claims (3)

1. Biodegradable granular polyolefin composition for its subsequent processing into various products, in the form of non-dusting granules with a size of 2 to 8 mm, bulk bulk density of granules 530-630 kg / m ³ , granule density 920-1300 kg / m ³ made by extrusion the melt obtained from the powder mixture, consisting of four parts, the first part of the concentration of the masterbatch contains a smaller part of the initial powdered polyolefin of its total amount in the composition with a melt flow rate of from 2.5 to 25 g / 10 min, the following two masterbatches contain, respectively, at least one biodegradable additive that promotes biodegradation of the product upon contact with the biological medium and concentrates of technological and target additives, as well as a powdered polyolefin with the same flow rate, and the remaining fourth part contains the remaining amount of powdered polyolefin in an amount of 26.315-88.925 wt.% (t), while the content of biodegradable (biodegradable) additives is 2-10 wt.% based on the entire composition. 2. The biodegradable granular polyolefin composition according to claim 1, characterized in that it contains processing stabilizers, antioxidants, lubricants and antistatic agents, an antioxidant, a biodegradable additive, a dye, a nucleator (nucleating agent), a bleach, a processing additive as technological and target additives , filler. 3. A method of obtaining a biodegradable granular polyolefin composition for its subsequent processing into various products according to one of claims 1 and 2, characterized in that first they prepare three masterbatch mixtures in the form of concentrates by dry mixing part of the powdered polyolefin of its total amount in the composition with technological and target additives, including at least one biodegradable additive, with a ratio of polyolefin and additives of masterbatches, respectively 1: 4, 1: 3, 1: 2, while the first m the exact mixture is prepared in a batch mixer for 85-95 min, the second and third mixtures are obtained in a continuous mixer, mixing for 3-4 minutes, then the resulting masterbatches are dry mixed with the remaining amount of powdered polyolefin in a continuous mixer for 3-4 minutes, carry out further mixing and homogenization of the components of the composition in the melt and granulation in a twin-screw granulator at a temperature of from 150 to 250 ° C.