Research on Recycling Technology of Raw Materials for Plastic Packaging II

Plastic packaging raw material recycling process route is:

Rough washing → crushing → fine washing → drying → plasticization → homogenization → granulation

The plasticization process is to put the waste plastic in a plastic mixer or a plastic extruder. After the internal spiral roller rotates and extrudes, it is heated to become a molten billet. After a period of time, the waste plastic has a uniform plasticity. Plasticization is the prerequisite for getting new recycled products. One of the purposes of plasticization is to prepare recycled pellets, and the second is to shape directly after plasticization. The direct molding can be completed on the plastic mixer after the plasticization is completed, and the granulation process is omitted. This is a process for directly manufacturing the packaging product (container) from the waste plastic.

The homogenization process is a kind of plasticization in which the waste plastic packaging material is mixed with various auxiliary agents or modifiers (plasticizers, lubricants, stabilizers, anti-aging agents, etc.) and uniformly mixed. There are two ways to homogenize: First, the mixing and plasticization are completed synchronously, and the broken waste plastic and various additives (plasticizers, etc.) are kneaded and homogenized to obtain various products (containers, etc.) ); Another is after homogenization granulation, homogenization granulation can make the materials mix very evenly. This is also the key to improving the quality of raw materials in recycling. Granulation is the use of a rapidly moving tool to cut waste plastic into fine, uniform particles as it is melt extruded.

Granulation process cold granulation and hot granulation two. The cold cut is that the extruded melt is cooled by a cold water tank and cut into pellets by a pelletizer. The eagerness is directly after the melt extrusion is cut by a rotary knife, and is sprayed with a water spray to cool, in order to prevent the particles from sticking to each other and affecting the quality.

Granulation can be done on granulators or pelletizers, respectively. The size of the material obtained by the granulation of the granulator is not uniform, and the granulator is a granulating apparatus for sheet-like plastics refining, which cuts the sheet-shaped extrudate into a rectangular or hexahedron by slitting and cross-cutting.

The plastic particles obtained by the granulation are raw materials used for remanufacturing plastic packaging obtained by using waste plastic packaging recycling technology. When it is used to make plastic packaging, it can be used entirely in this granular material or in part (added in proportion to the original material). If all of these materials are used, the quality of plastic packaging will be reduced.

3 Process and Equipment Problems for Recycling Raw Material Particles to Produce Packaging or Other Products

The above-obtained particle raw materials are the ultimate purpose of recycling plastic packaging material type recycling technology. The use of this recycled particulate raw material to prepare a variety of products (packaging and other), the process can fully use the existing plastic molding processing technology and equipment, including the following processes and equipment:

Extrusion molding process and equipment Injection molding process and equipment Calendering process and equipment Blow molding process and equipment Molding process and equipment Hot press molding process and equipment Foam molding process and equipment Casting molding process and equipment Spinning molding process and equipment

The above molding processes and equipment are relatively mature and are widely used in plastic molding processing. Reference can be made to the plastic processing and equipment information, which will not be repeated here.

4 Other problems

The use of the recycled plastic material particles obtained should pay attention to the following points:

(1) Reduce use

The use of recycled raw material particles to process packaging products may result in packaging products that do not meet the requirements of raw materials. Reduced use can then be used, such as packaging of raw materials for export product packaging, and recycled packaging materials for domestic product packaging.

(2) Use in proportion

The raw granules and the recycled material are proportioned according to a certain ratio, and then the package is prepared to improve the quality.

(3) Composite processing

The packaging made from recycled recycled plastic particles is compounded with other high performance materials to improve the performance of recycled plastic packaging.

(3) Add enhancer

In the process of making recycled packaging from recycled plastic particles, additives that improve packaging performance are added to improve the packaging performance of recycled plastics.

Yang Ting Yang Fuxin (Zhuzhou Institute of Technology, Zhuzhou, Hunan)

China Packaging Industry