RU2408621C2 - Polymeric composition for moulding biodegradable articles form molten mass - Google Patents

Abstract

FIELD: chemistry. ^ SUBSTANCE: composition contains polyethylene production and/or household wastes, beet pulp and bentonite as a processing additive. ^ EFFECT: disclosed composition has rheological characteristics which meet requirements for polymeric materials for their possible processing on conventional equipment, as well as required operational characteristics, including biodegradability. ^ 4 ex, 2 tbl

Description

The invention relates to the production of plastics on the basis of industrial and household waste polyethylene used in the production of various thermoformed products, films used for the national economy (corrections for flower and vegetable seedlings, film for mulching and destruction of weeds with the effect of warming), etc.

In the difficult environmental situation prevailing in the world, the use of biodegradable polymeric materials for obtaining consumer goods is the main direction of reducing the amount of solid waste, because 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. Low and highly filled starch compositions are known. 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, CL 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. T.1154, No. 4;

US patent 5208267, C08J 9/02, 9/12, publ. 05/03/2004 volume 1150, No. 1,

Patent RU 2095379, publ. 06/30/98;

Patent RU 2180670, publ. 01/06/2000;

Patent RU 2174132, publ. 06/23/2000;

EP patent 1338405, MLK ВСС 67/24. C08J 5/06, publ. August 27, 2003;

US patent 6054510, IPC7 C08L 63/00, publ. 04/25/2000).

Archer Daniels Midland, USA, developed a PolyClean 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 Caprolactam copolycondensation product, adipic acid and hexamethylenediamine 1 ... 10 Glycerol twenty Water twenty Titanium dioxide twenty Ultramarine 0.008

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 degassing unit, which increases energy consumption.

The proposed solution simplifies the technology of manufacturing thermoplastic by eliminating the use of liquid components, significantly reduces the cost of the finished product, because the raw material for thermoplastics is polyethylene waste (industrial and domestic).

In addition, it contributes to environmental protection, as the waste is not disposed of, but is again used for the manufacture of various products.

The objective of the invention is the creation of a thermoplastic composition using a biodegradable filler (sugar industry waste), products from which are destroyed by the action of light, moisture and soil microflora.

This is achieved by the fact that the biodegradable thermoplastic composition for products according to the invention contains waste polyethylene (60 ... 89 wt.%), Biodegradable filler, which is used as sugar industry sugar beet pulp (10 ... 30 wt.%) And bentonite (1 ... 10 wt.%).

According to the invention, as a biodegradable filler, stimulating the process of biological destruction of the final products made from polyethylene waste, beet pulp is used in an amount of 10 ... 30 wt.%.

Beet pulp used for filling beet pulp (insoluble beet sugar mass cut into chips) has the following characteristics:

- pectin substances 50%;

- cellulose and hemicellulose 47%;

- protein 2%;

ash 1%;

- moisture mass fraction,%, no more than 14.0;

- mass fraction of crude protein,%, not less than 7.0.

The technological additive was selected on the basis of the need to create a homogeneous system. Bentonite is used as a dispersant - a substance that facilitates the uniform distribution of components in a polymer matrix when mixed (Technology for processing plastics and elastomers in the production of polymer film materials and artificial leather. G.P. Andrianova, K.L. Polyakova, Yu.S. Matveev, M., "Kolos S", 2008, 367 pp.).

Industrial and household waste polyethylene was used as a polymeric binder, having the following indicators: particles (crumbs) of different colors without mechanical impurities, the amount of foreign matter not more than 10%, the mass fraction of moisture not more than 2%.

Such a composition has rheological characteristics that correspond to 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 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, the optimal ratio is “beet pulp - waste polyethylene” (10-30: 60: 89). The proposed composition is made as follows.

Example 1

30 mass parts of beet pulp are mixed with 60 mass parts of polyethylene waste and 10 mass parts of bentonite in a high-speed turbo mixer for 5 minutes. The resulting mixture enters the extruder for homogenization. The melt temperature at the outlet is 140-160 ° 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, a film or sheet is made on an extruder with a slit head, from which products of various standard sizes are molded, and on a molding machine - various containers.

Example 2

Preparation of the composition according to example 1. The amount of beet pulp 10 wt.%. Polyethylene waste 89 wt.%, Bentonite 1 wt.%.

Example 3

Preparation of the composition according to example 1. The amount of beet pulp 20 wt.%, Waste polyethylene 70 wt.%, Bentonite 10 wt.%.

The composition of the compositions of the examples are shown in table 1. In the examples, their optimum amounts are given.

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 industrial and domestic polyethylene waste, a biodegradable filler, which is used as beet pulp, and a technological additive, which is used as bentonite, in the following ratio, wt.%:
polyethylene waste 60-89 beet pulp 10-30 bentonite 1-10