Why can't the shoe industry do without calcium carbonate?
Which shoe materials need calcium carbonate powder
The main resins used in the shoe industry are PVC (polyvinyl chloride), RB (rubber), PU (polyurethane), TPR (thermoplastic rubber) and so on, and the addition of calcium powder mainly plays a role in reducing the cost and increasing the abrasion resistance of shoes.
In this article, we will briefly introduce the application of inorganic filler for several common shoe sole materials, because the shoe sole filler involves more than calcium carbonate powder materials, but also some related fillers incidentally introduced for your reference.
RB rubber sole
Rubber sole materials can be roughly divided into natural rubber or synthetic rubber. The advantage of natural rubber is that it is very soft and flexible, which is suitable for all kinds of sports. However, the disadvantage is also very obvious, that is, it is not wear-resistant, indoor sports shoes are mostly used natural rubber.
Rubber soles are generally adapted to precipitated silica as a filler (can play a reinforcing role), some formulations need to add a small amount of calcium carbonate, in order to appropriately enhance the abrasion resistance of the soles as well as resistance to yellowing properties.
PVC soles
PVC is used as the material for full-plastic sandals, tall miner's shoes, rain shoes, slippers and soles. Generally add light calcium, some formulations add 400-800 mesh heavy calcium, according to different requirements, the dosage is about 3-5%.
TPR soles
Thermoplastic rubber (TPR) sole is a material with both rubber and thermoplastic characteristics, with rubber properties and can be processed and recycled according to thermoplastic, and can be made into rubber products by injection molding, extrusion molding and blow molding with ordinary plastic molding machines. Usually, if you need anti-scratch formula, you will add silica and nano-calcium, etc. If you need transparent effect, you can add silica and transparent powder, etc. If you need lower quality, you can add a small amount of silica, and add bicarbonate powder.
EVA One Shot Sole
EVA is mainly used for the midsole of sports shoes, casual shoes, outdoor shoes, travel shoes, and lightweight slippers, which are the most used products. The main filler added is talcum powder, the amount of addition varies from 5-20%. The midsole has higher requirements for whiteness and talc quality, and the light-colored material of slippers also has higher requirements for whiteness, above 90 degrees, with silica content ranging from 35-55%.EVA sole is the lightest material in terms of weight. According to the different quality requirements can add 800-3000 mesh talc as filler.
EVA Sheet Foam
EVA sheet large foam for the template foam whole bed molding, and then according to the need to cut into different thicknesses of the sheet or secondary molding of the sole, in the slippers and the midsole are in the foam material.
Most of these sheets are made by adding 325-600 mesh of heavy calcium, and 1250-2000 mesh of heavy calcium will be added if high density is required, and 600-800 mesh of talcum powder, or even 1250 mesh of talcum powder will be added if some formulas require high surface flatness and elasticity of the sheets. Some special requirement products will also use barium sulfate powder.
