As a key component connecting the upper and the sole, the rubber upper midsole directly affects the comfort and performance of the shoe, and is mainly divided into two types: sponge midsole and hard midsole. Natural rubber has excellent elasticity and abrasion resistance, which is an ideal raw material for the production of rubber parts of rubber shoes; However, the price of natural rubber is high and the price fluctuates greatly, and the performance demand for rubber in the midsole of vinyl shoes is relatively low, so a large amount of reclaimed rubber can be mixed to effectively reduce the production cost of sponge midsole and hard midsole of vinyl rubber shoes.
1. The performance requirements of the vinyl rubber shoe sponge midsole are different from the hard midsole
(1) Sponge midsole: The sponge midsole of rubber shoes mainly plays a cushioning role in rubber shoes, requiring the rubber to have excellent softness, lasting elasticity and compression deformation resistance, as well as good aging resistance; In the process of wearing, the sponge is required to have small compression deformation, good elasticity and flexibility, and a closed-cell structure. When a large amount of reclaimed rubber is used to produce the sponge midsole of rubber shoes, it is necessary to ensure that the rubber material has enough softness and elasticity to play a cushioning role.
(2) Hard midsole: The hard midsole of rubber shoes mainly plays a supporting and protective role in rubber shoes, and has higher requirements in terms of strength and durability, and has incomparable hardness, stiffness, wear resistance and bending resistance of sponge midsole. When a large number of reclaimed rubber is used to produce hard midsoles of vinyl-faced rubber shoes, the physical and mechanical properties and wear resistance of rubber materials are required to be higher.
2. Design the difference among the sponge midsole and the hard midsole formula of vinyl rubber shoes
(1) Sponge midsole
When using a large amount of reclaimed rubber to produce the sponge midsole of vinyl rubber shoes, the glue content is generally controlled among 5% and 10%, and the amount of reclaimed rubber is 13-15 times that of raw rubber, and reclaimed rubber can be completely used; Foaming agents are used in the formulation to produce bubbles E4LYY117 form a spongy structure, such as foaming agent H, baking soda, etc.; The selection of vulcanization system needs to consider the coordination of pore rate and vulcanization rate, and accelerator M, accelerator DM and accelerator D are generally used together. Calcium carbonate and clay are commonly used in the filling system; Commarone, motor oil, petroleum jelly, industrial grease, black ointment, etc., are used to improve the processability and softness of the compound.
(2) Hard midsole
When natural rubber and a large amount of reclaimed rubber are used together to produce the hard midsole of rubber-faced rubber shoes, the glue content is generally controlled among 5% and 10%, and the amount of reclaimed rubber is 8-10 times that of raw rubber, or reclaimed rubber is completely used; In the vulcanization system in the formula, accelerator M and accelerator D are mostly used together to promote sulfur vulcanization; The filler is light calcium carbonate, clay or kaolin, etc.; An appropriate amount of crushed cloth chips can improve the flexural resistance of the rubber material and the hardness of the midsole after vulcanization; Use plasticizers sparingly.
3. A large amount of natural rubber is mixed with reclaimed rubber to produce vinyl rubber shoe sponge midsole and hard midsole vulcanization formula
(1) A large number of reclaimed rubber is used to produce vinyl rubber shoe sponge midsole vulcanization formula
5 parts of natural rubber, 95 parts of reclaimed rubber, 0.6 parts of zinc oxide, 2.4 parts of stearic acid, 0.5 parts of antioxidant, 10 parts of clay, 1.8 parts of industrial fat, 0.6 parts of foaming agent H, 0.25 parts of accelerator M, 0.45 parts of accelerator DM, 0.2 parts of accelerator D, 1.2 parts of sulfur; A total of 118 copies.
(2) A large number of reclaimed rubber is used to produce vinyl rubber shoes hard midsole vulcanization formula
10 parts of natural rubber, 90 parts of reclaimed rubber, 0.4 parts of zinc oxide, 0.25 parts of stearic acid, 60 parts of light calcium carbonate, 37 parts of clay, 3 parts of engine oil, 5 parts of cloth crumbs, 0.45 parts of accelerator M, 0.25 parts of accelerator D, 1.25 parts of sulfur; Total 207.6 copies.
When a large amount of reclaimed rubber is used together with natural rubber to produce rubber shoe sponge midsole and hard midsole, other external natural rubber can also be used to replace standard natural rubber to further reduce the cost of raw materials. The performance requirements of the sponge midsole and hard midsole of vinyl rubber shoes are different, the basic vulcanization formula is different, and the production process is different.
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