Plastic footwear includes foaming, non-foaming sandals and slippers, as well as a variety of plastic soles, mainly PVC, PE, PE / EVa. Before recycling and recycling, the first sorting is carried out, generally based on manual sorting. The sorted waste shoes are regenerated according to the type of materials and used.
1. Recycling of PVC plastic footwear: the addition of PVC plastic footwear mainly adopts the method of regranulation
The waste PVC shoe material which has been sorted and washed is mixed on a two-roller refining machine. At this time, according to the specific source and quality of the waste, various kinds of fine additives are added, and after sufficient mixing, the pieces are cut, diced, and filtered. Extrusion to produce recycled pellets.
The addition of auxiliary additives depends on the condition of the waste PVC shoe material. If it is the scrap of the factory, it is not necessary to add the additive, as long as it is mixed with the new material in a certain proportion, the ratio of the continuous material to the new material can reach 1:1 or even Higher, for foamed PVC waste, the mixing temperature should be properly increased, and the mixing time should be extended to remove air bubbles.
For the waste PVC shoe materials with poor quality, various additives are added, and various impurities are removed by extrusion filtration. The formula for determining the amount of plasticizer added is:
bC1K1C2K2b
X=a(a1+a2+...)×(1+)
100+b100+C1K1100+C2K2100
a=a1+a2+...
Where: X - the quality of the plasticizer to be added to the recycled ingredients, kg
a——Recycled ingredients, total mass of waste plastics, kg
A1a2...——Quality kg of some waste plastics recycled
b——Quality ratio of plasticizer required in recycled raw meal, %
C1C2...——The mass ratio of plasticizer in the original formulation of a certain kind of recycled plastics, %
K1K2... - The retention factor of plasticizers for certain recycled plastics, which is usually determined empirically.
Other additives, such as stabilizers, lubricants, etc., can in principle also be determined using the above formula and experience.
Waste PVC film, film is commonly used to make PVC recycled materials for shoes. The content of plasticizer in general PVC film is about 42 parts. Now we introduce several ingredients (using the ratio of factory PVC foam trim).
Formula 1
Factory PVC foam shoe scrap 10kg waste PVC film 25kg
New material powder 10kg
The formula of the new material powder is as follows:
PVC (XO-4) 100 (parts by mass) dibasic lead sulfate 5.0
DOP35 dibasic lead phosphite 2.0
DBP60 medium yellow pulp 1.0
Mixed ester 25 iron oxide red paste 2.2
Barium stearate 3.5 carbon black pulp 0.14
Formula 2
Factory PVC foam trim 30kg new powder cooking 10kg
Waste PVC film 5kg
The new powder formula is as follows.
PVC (XO-4) 100 (parts by mass) DOP25
Tribasic lead sulfate (powder) 0.5DBP30
Barium stearate 0.7
2. PE.PE/EVa shoe material recycling: PE, PE/EVa shoe material is usually a foamed product. The factory scrap is mainly granulated after pulverization. Added to the new material, the waste collected in the society can be mainly used for agricultural tools, fences and the like.
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