RU2318006C1 - Biologically degradable thermoplastic composition with using of rye flour - Google Patents

Abstract

FIELD: biopolymers.

SUBSTANCE: invention relates to production of plastic masses based on ethylene and vinylacetate copolymer for mould products useful in food processing industry and agriculture. Claimed composition contains 50-68.7 mass % of ethylene and vinylacetate copolymer, biologically degradable filler containing rye flour in amount of 30-48,7 mass % and additives such as surfactant in amount of 0.1 mass %, maize amylacetate in amount of 1 mass %, and 0.2 mass % of methylcellulose.

EFFECT: new biologically degradable composition.

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Description

The invention relates to the production of plastics based on a copolymer of ethylene and vinyl acetate used in the manufacture of various thermoformed products (consumer packaging, utensils, etc.), films that are used both in contact with food and for technological purposes for the national economy (corrections for flower and vegetable seedlings).

In the difficult environmental situation in the world, the use of biodegradable polymeric materials to produce consumer goods is the main direction of reducing the amount of solid waste, as it will ensure their rapid decomposition under the influence of climatic factors and microorganisms.

One of the possible directions for the production of biodegradable materials is the modification of traditional polymers. The combination of a synthetic polymer with a natural active filler can give the material a new set of properties.

Such materials are filled systems where starch is used as an active filler. Known low- and highly-filled starch compositions. The most important quality of these compositions is their ability to decompose under the influence of natural environmental factors: light, heat, microorganisms. Known biodegradable packaging material based on starch (France, 2691467, class 5 C08J 5/18, B65D 1/10, 65/46, C08L 3/20).

Recently, a significant number of patents and scientific publications have appeared containing information on the use of starches as fillers for imparting biodegradability to polymer compositions (US patent 5248702, C08J 9/12, publ., Volume 1154, No. 4; US patent 5208267, C08J 9 / 02, 9/12, published on May 93, 2004, volume 1150, No. 1; patent RU 2095379, published on 06/30/98; patent RU 2180670, published on January 6, 2000; patent RU 2174132, published June 23, 2000; EPO patent 1338405, MKL В29С 67/24, С08J 5/06, published on August 27, 2003; US patent 6054510, IPC ⁷ С08L 63/00, published on April 25, 2000).

Archer Daniels Midland USA has developed a Poly Clean brand concentrate based on polyethylene to produce biodegradable films. The concentrate contains 40% starch and an oxidizable additive, the amount of starch in the final product is 5-6%. The disadvantage of this composition is that only the starch component undergoes biological destruction in it.

The closest in technical essence and the achieved result to the proposed invention is a composition according to the patent of the Russian Federation No. 2180670:

starch one hundred copolycondensation product caprolactam, adipic acids and hexamethylenediamine 1-10

Obtaining the composition of the prototype requires the use of a plasticizer (water-glycerin mixture).

If there is water in the composition, the technological scheme of processing requires an additional unit - degassing, which increases energy consumption.

The proposed solution simplifies the technology of manufacturing thermoplastics and eliminates the use of liquid components.

The objective of the invention is the creation of a thermoplastic composition using a biodegradable filler - rye flour, the products of which are destroyed by light, moisture and microflora of the soil.

This is achieved by the fact that the biodegradable thermoplastic composition for products according to the invention contains a copolymer of ethylene and vinyl acetate (50-68.7 wt.%), A biodegradable filler, which is used as rye flour (30-48.7 wt.%) and technological additives, which use a cationic surfactant (0.1 wt.%), corn amyl acetate (1 wt.%) and methyl cellulose (0.2 wt.%).

Technological additives with different functional purposes were selected according to the principle of the need to create a heterogeneous system with specified values of its effective viscosity in the selected processing temperature range. Cationic surfactants were selected from a series of quaternary ammonium salts: alkoxymethylpyridinium chloride, cntylpyridinium chloride (trademark Katapav, P-26), which were used in the composition to improve the compatibility of the ingredients and achieve homogenization, and prevent clumping of the powder mixture. Corn cellulose and corn amyl acetate are water-retaining and film-forming modifiers.

The indicated components were introduced in the required amounts using the techniques of introducing small additives of solid consistency that are generally accepted in the technology for producing plastics.

Such a composition has rheological characteristics that meet the requirements for materials for processing on traditional equipment for plastics (extruder, injection molding machine).

Products from the proposed composition have predetermined operational characteristics, including biological destructibility.

The rye flour used for filling has the following physical characteristics: humidity 15%, ash content not more than 1.45%, proteins 8.9 g, fats 1.7 g, carbohydrates 61.8 g.

As a polymer binder, a copolymer of ethylene and vinyl acetate (SEVA) was used, which has the following physicochemical characteristics: vinyl acetate content from 5 to 30 wt.%, Density 0.928-0.945 7 / cm ³ , tensile elongation 600-800%, breaking stress at a break of 9-12 MPa.

The polymer binder plays the role of a dispersion medium. The surface of the filler is able to actively interact with the polymer binder, exerting a certain influence on the rheological properties of the compositions and the physical and mechanical characteristics of the products.

The filler and polymer are hydrophilic and have surface active centers capable of forming fairly strong hydrogen bonds. The adhesive interaction at the polymer-biodegradable interface is an adsorption interaction of two bodies.

The choice of the optimal ratios of the polymer and the filler is determined by the theoretical filling limit, which is determined by the interaction strength at the phase boundary.

According to the invention, as a biodegradable filler, stimulating the process of biological destruction of the final products made from a copolymer of ethylene and vinyl acetate, rye flour is used in an amount of (30-48.7) wt.%.

The proposed copolymer of ethylene and vinyl acetate has high physicomechanical properties, increased elasticity, deformation heat resistance during processing, has sufficient water absorption (1-3%), which contributes to the biodegradation of finished products during disposal.

The optimal according to the invention is the ratio of rye flour - a copolymer of ethylene and vinyl acetate (SEVA) (30-48.7) :( 50-68.7), a cationic surfactant (0.1 wt.%), Corn amyl acetate (1 wt. %) and methyl cellulose (0.2% by weight).

The invention is carried out as follows.

Example 1

48.7% by weight of rye flour are mixed with 50% by weight of a copolymer of ethylene and vinyl acetate; 0.1 wt.% Cationic surfactant (alkoxymethylpyridinium chloride), 1 wt.% Corn amyl acetate; 0.2 wt.% Methyl cellulose in a high-speed turbo mixer for 5 minutes The resulting mixture enters the extruder for homogenization. The melt temperature at the outlet of the extruder head is 90-100 ° C.

The obtained bundles are cooled by a stream of cold air and cut into granules with a size of 4-6 mm. From the obtained granules on a slit head extruder, a sheet is obtained from which the corrections and containers of various sizes are formed.

Example 2

The preparation of the composition according to example 1. The amount of rye flour 30 wt.%, A copolymer of ethylene and vinyl acetate 68.7 wt.%. The granules obtained from this composition are used to make the film by blown extrusion, at a temperature of 120-150 ° C.

Example 3

The preparation of the composition according to example 1. As a cationic surfactant, cetylpyridinium chloride is used in an amount of 0.1 wt.%.

The compositions of the compositions of the examples are shown in table 1. Technological additives are used in the proposed compositions in traditional proportions. In the examples, their optimum amounts are given.

Table 1 Example No. Filler Polymer Technological Additives Technological and operational properties Rye flour Prototype polymer * Ethylene Vinyl Acetate Copolymer (SEVA) Cationic surfactant, wt.% Amyl acetate corn wt.% Cellulose, wt.% Melt processing temperature, ° С PTR, g / 10 min. load Water absorption in 24 hours,% Microbiological resistance Prototype - one hundred - - - - 135 fifteen fifteen Seed 10 cm surface 1 × 30 units. Example 1 48.7 - fifty 0,1 ** one 0.2 90-100 eighteen 35 Seed 10 cm surface 1 × 70 units. Example 2 thirty - 68.7 0.1 one 0.2 120-150 22 twenty Seed 10 cm surface 1 × 40 units. Example 3 48.7 - fifty 0.1 *** one 0.2 90-100 eighteen 35 Seed 10 cm surface 1 × 70 units. * A mixture of corn starch with the copolycondensation product of caprolactam, adipic acid and hexamethylene diacetate
** Alkoxymethylpyridinium chloride
*** Cetylpyridinium chloride

Table 2 shows the methods for determining the properties that provide the objective of the invention.

table 2 №№ Name of indications Test methods one The melt flow rate of the composition (MFR) at a temperature of 120 ° C, g / 10 min GOST 11645-73 2 The processing temperature of the composition, ° C GOST 11645-73 3 Water absorption,% for 24 hours GOST 4650-80 four Microbiological resistance GOST 9.053-75 GOST 9.049-91

Claims (1)

A biodegradable thermoplastic composition for products, characterized in that it contains a copolymer of ethylene and vinyl acetate, a biodegradable filler, which is used as rye flour and processing aids, which use a cationic surfactant, corn amyl acetate and methyl cellulose, in the following ratio of components, wt.%: ethylene vinyl acetate copolymer 50-68.7 Rye flour 30-48.7 cationic surface active substance 0.1 corn amyl acetate one cellulose 0.2