Plastic bottle recycling

Bottles include refreshing beverage bottles, mineral water bottles, liquid food bottles, cosmetics bottles, etc. The materials used are polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (polyester) ( PET) etc. Usually, mineral water bottles are made of PVC or PET, carbonated beverage bottles are made of PET, refreshing drink bottles, liquid food bottles are made of PVC, PE, detergent bottles, cosmetic bottles, milk bottles, and lactic acid bacteria drinks are mostly made of PE.

The various types of bottles that are recycled are generally manually sorted and then recycled according to different materials. At present, there are many technologies and equipment for the recycling of various types of bottles.

(1) PET bottle recycling, PET bottles used in large quantities for Coca-Cola, Pepsi, Sprite and other carbonated beverages, most of which are currently composed of PET bottles and HDPE bottles, caps material HDPE, trademark biaxially oriented polypropylene (BOPP) The film is adhered to the bottle body using an EVA type adhesive. Recycling granulation is used as a way to recycle the PET bottle. Alcoholysis and other methods. Regardless of the method used, the PET bottle must first be separated from other bottles, and the PET bottle body must be separated from the bottom of the bottle.

1 Separation: The mixed vials are crushed by a conveyor belt and then separated by density.

2 Regeneration granulation: Recycle granulation can be used extruder. The separated PET scraps are extruded into pellets through an extruder to make pellets. To prevent the water absorption during extrusion from deteriorating the physical viscosity, the pellets should be dried before extrusion. The use of PET pellets is as follows:

a, Remanufacturing of PET bottles, recycled pellets can not be used in direct contact with food, but can be used in the middle layer of three-layer PET bottles, and then into carbonated beverage bottles.

b. Spinning to make fibers, recycled PET material can be used to spin fibers, used as pillows, mattresses, sleeping bags, felts, etc.

c. Glass fiber reinforced materials, glass fiber reinforced recycled PET has good heat resistance and mechanical strength, can be used to make automotive parts, such as heat-resistant car wheel cover, and its thermal distortion temperature can reach 240 degrees. The flexural modulus is 9500 MPa, the flexural strength is 214 MPa, and the impact strength is 15 kf/m2.

d. Blend modification, recycled PET material can be blended with other polymers to obtain various modified materials, such as blending with PE, can obtain PET blends with improved impact properties, PE: PET is (10 ~50): (90~50): If a small amount of polypropylene is added, the dimensional stability of the blend can be significantly improved. Since the polarities of PE and PET are quite different, compatibility treatment is required during blending, and the compatibility is generally improved by graft modification of polyolefins.

3 alcoholysis, PET waste in the presence of alkaline catalysts for alcoholysis, and then adding dicarboxylic anhydride and other polycondensation, to get the acid value of products greater than 12, diluted, filtered, adding the right amount of catalyst, can be prepared alkyd resin paint. The recipe is shown in the table below. Reaction temperature 80~85 degrees, reaction 4~5h

PET waste alcohol solution coating formula

Material; Adding amount;; Material; Adding amount;

Material; 25; N-Hydroxymethyl acrylamide; Diethylene glycol nonionic emulsifier

Dibutyl phthalate 18; Anionic emulsifier 1.1

Vinyl Acetate 24 Persulfate Initiator 1.4

Methylstyrene 7 water 130

Methacrylic acid 1

Another example is the reaction of PET wastes with polyols at 220 to 250 oc. Solvents are used to obtain insulating lacquer with three-dimensional network structure. The quality meets the requirements of GB6109. 3 Others, PET bottles can also be used to make plasticizers: 2-Ethylhexyl phthalate (DOTP) has a plasticizing effect similar to dioctyl phthalate (DOP) and is slightly superior to DOP in electrical properties and low temperature flexibility. Waste PET bottles can also be made into adhesives and unsaturated polyesters using similar methods as used PET films.

(2) The recycling of PVC bottles and PVC recycling procedures are as follows.

PVC bottle cleaning sorting and smashing finely crushed and regenerated products First, the PVC bottle is cleaned with steam and alkali solution and the trademark is removed, and then the machine and the manpower are used to separate the first, and the PVC bottle after the sorting is performed.
Sub-pulverization, the final fineness of 500 ~ 1200μm powdery recycled products, purity up to 99.98%

(3) Recycling of PE bottles. The PE used as bottle material is mainly HDPE. There are dairy products bottles, food bottles, cosmetics bottles, etc. After sorting, the HDPE recovery bottles after cleaning can be crushed and selected. Their uses are as follows:

1 Use coloring Coke bottle holder

2 Used for coextruding the middle core layer of the pipe

3 Filled talcum powder or glass fiber manufacturing flower cup or injection molding products.

4 It is composited with the fiber and used as artificial wood. Because the wood fiber has poor compatibility with HDPE, it is necessary to add an appropriate coupling agent or use activated wood fiber.

5 Manufacture of artificial gravel, crushing HDPE bottles into small pieces or granules, and then sticking the surface with yarn, made of metal, etc., and then mixing them with concrete or asphalt for use in civil construction materials.

Reprinted from: China Waste Net