RU2200659C2 - Method of manufacture of articles from plastic wastes - Google Patents

Abstract

FIELD: technology of processing thermoplastic polymer materials; manufacture of articles from plastic polymer wastes. SUBSTANCE: method includes grinding, washing, drying and preheating the wastes which are subjected to injection molding. Prior to grinding secondary plastic wastes, they are divided in two parts: first part is single-type thermoplastic secondary waste after single processing without considerable damage of polymer structure whose characteristics are within boundaries of characteristics of primary initial material; second part is secondary raw material from articles made from polyethylene and/or polypropylene and polystyrene possessing known characteristics. After grinding, ground material is subjected to separation of it from admixtures before washing. After drying, raw material blend is prepared from dried secondary material by adding 20-50% of material of first part to material of second part whose amount is equal to 80-50% of total amount of raw material. EFFECT: enhanced efficiency. 2 cl, 2 tbl

Description

 The invention relates to a technology for processing thermoplastic polymeric materials and can be used in the manufacture of products from plastic polymer waste.

 Currently, there is a big problem associated with the rational use of secondary raw materials in the areas of production and consumption of plastics.

 It is known that the main types of secondary polymer raw materials are technological waste from the production and processing of plastics in the form of ingots, defective products, including large-sized ones, sprues, films, fibers, pipes and molded products, as well as used plastic products that have expired consumer goods, bags, films, containers for various purposes, etc.

 Most of the generated wastes from processing large-capacity polymers are again processed into products at the place of their formation or at other enterprises.

 Recently, the problem of using constantly increasing volumes of plastic waste in the form of worn-out products for various purposes, which have lost their consumer properties due to their physical and moral deterioration, has remained more difficult.

 The most rational way of using technological polymer waste and polymer consumption waste is to process them into useful products.

 At the same time, it is known that multiple processing leads to a change in the structure and properties of the material, and the deterioration of properties is largely uncontrollable. Therefore, regenerates, as a rule, are used for the production of products with lower consumer properties.

 It is known (see, for example, L. Starke’s book “The Use of Industrial and Domestic Waste”, L., Chemistry, 1987, p.132) that in the manufacture of products from plastic waste of polyethylene, polypropylene, as well as other polymers in the feedstock 80 ... 90% of polyethylene, polypropylene or other wastes must be contained and 10. ..20% of primary polyethylene (GOST 16338-85) or polypropylene (GOST 26996-86).

 The closest in technical essence and the achieved effect of its use to the claimed method is a known method of manufacturing products from plastic waste according to the patent of the Russian Federation N 2005605, 29 V 17/00, 1992, according to which the plastic waste is first crushed (cut into pieces), then they are washed and dried, after which they are heated, rolled, granulated, and products are formed from the granules by injection molding in standard mode — samples for mechanical tests.

 This method, although it allows the processing of plastic waste into some types of products, however, it does not allow the manufacture of products with predetermined guaranteed characteristics.

 The objective of the present invention is to significantly increase the efficiency of the manufacturing process of products from plastic waste.

 This problem is solved primarily due to the technical result from the use of the invention, which consists in a significant reduction in the cost of the original plastic raw materials by replacing the original primary raw materials with the original secondary raw materials with desired characteristics that are within the characteristics of the primary raw materials.

This result is achieved by the fact that in the known method of manufacturing products from plastic waste, which consists in the fact that the plastic waste is first crushed, then washed, dried, heated and injection molded to form the product,
firstly, before grinding, secondary plastic waste of the same type is divided into two parts:
- on the first one, consisting of the same type of thermoplastic secondary raw material after a single processing without significant damage to the polymer structure with characteristics lying within the characteristics of the original primary material, for example with the following close characteristics of physical and mechanical properties (see table 1),
- on the second, consisting of recycled materials from products made of polyethylene, and / or polypropylene, or polystyrene with unknown characteristics,
secondly, after grinding before washing, the crushed material is separated, separating it from impurities,
thirdly, after drying, a dried mixture is made from the dried raw secondary material by adding a second part to the material, which is 80. ..50% of the total amount of raw material, 20 ... 50% of the material of the first part.

 The introduction of additional operations and special conditions for performing existing operations can significantly increase the efficiency of the process of manufacturing products from plastic waste.

 The possibility of implementing this method is confirmed by the following description of the proposed technology for the manufacture of plastic waste products.

1. Secondary plastic waste is divided (for example, manually) into two parts:
- on the first one, consisting of the same type of secondary thermoplastic raw material after a single processing without significant damage to the polymer structure with characteristics lying within the characteristics of the original primary material, for example, with the following close physical and mechanical properties determined experimentally (see table 2),
- on the second, consisting of secondary raw materials from products made of polyethylene, and / or polypropylene, or polystyrene with unknown characteristics.

 2. Sorted plastic waste is crushed, for example, using an IPR-450 crusher. Moreover, the degree of crushing is determined by the diameter of the holes of the separating mesh and is not more than 5 ... 8 mm.

 3. The crushed material is separated (separated from impurities), for example, using a conventional separator (see, for example, the book "Machines and apparatuses of chemical production", edited by II Chernobylsky, M., Mashgiz, 1959, p. .25).

 4. The separated material is washed with water.

5. The washed material using a drying chamber, for example, a spiral type is dried with hot air at a temperature of 20 ... 80 ^o C.

 6. From the dried raw secondary material, an injection mixture is made by adding to the material a second part, comprising 80 ... 50% of the total amount of raw material, 20 ... 50% of the material of the first part.

 7. The injection mixture, using, for example, an electric heating cylinder, is heated with stirring to a plasticization temperature.

 8. Injection molded product.

Using the invention allows:
1. Significantly increase the efficiency of the process of manufacturing products from plastic waste by reducing the cost of primary primary plastic raw materials by replacing the original primary raw materials with a portion of the initial secondary raw materials with acceptable characteristics that are within the characteristics of the primary raw materials.

 2. To increase the efficiency of processing and use of plastic waste by more thorough sorting.

 3. Improve the environmental situation in the region by making it possible to turn useless and even harmful plastic waste into useful, harmless consumer goods.

 4. To expand the base of raw materials due to the rational use of industrial waste and consumption waste in the form of worn and lost their consumer value products from thermoplastics.

 5. Improve the quality of plastic products in the recycling of thermoplastics at no additional cost or with minimal cost.

 6. To increase the efficiency of processing and use of plastic waste by ensuring the possibility of abandoning one of the most important provisions of the existing technology in practice - the mandatory use of a primary polymer to improve the secondary mixtures that are used for the manufacture of products, and the transition to 100% use of the “secondary” in the formulation of injection molding machines.

Claims (2)

 1. A method of manufacturing products from plastic waste, in which plastic waste is crushed, washed, dried, heated and molded by injection molding, characterized in that before grinding the secondary plastic waste is divided into two parts, the first part from the same type of thermoplastic secondary raw material after a single processing without significant damage to the polymer structure with characteristics lying within the characteristics of the source of the primary material, and the second part of the secondary raw materials and of articles made of polyethylene and / or polypropylene or polystyrene with unknown characteristics, and after grinding before washing, the crushed material is separated, separating it from impurities, after drying, a dried injection material is prepared from the dried raw secondary material by adding a second part to the material of 80- 50% of the total amount of raw material, 20-50% of the material of the first part. 2. A method of manufacturing products from plastic waste according to claim 1, characterized in that either high pressure polyethylene with tensile strength of 170-100 kgf / cm ² , with strength, is used as a single type thermoplastic secondary raw material after a single processing without significant damage to the polymer structure with a bend of 200-170 kgf / cm ² , with a shear strength of 170-140 kgf / cm ² , with a yield strength of 90-160 kgf / cm ² , with a relative elongation at the beginning of the flow of 15-20%, and at break - 800- 500%, or low-pressure polyethylene with strength at tension 450-180 kgf / cm ² , with a bending strength of 400-200 kgf / cm ² , with a shear strength of 360-200 kgf / cm ² , with a yield strength of 250-350 kgf / cm ² , with elongation at the beginning of the flow 10-12%, and at break - 1200-50%, either polypropylene with tensile strength of 300-350% kgf / cm ² , yield strength 270-300 kgf / cm ² , or polystyrene with tensile strength of 300-500 kgf / cm ² , with a bending strength of 500-1000 kgf / cm ² and elongation at break of 1-2%.

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