The rubber foam sole has light texture, good elasticity, tear resistance and aging resistance. It is widely used in a large number of shoes. Many sponge foaming midsole production processes use reclaimed rubber in large quantities to reduce the cost of raw materials. In the middle of the reclaimed rubber sponge, the inorganic foaming agent and the organic foaming agent are used in combination, which can meet the performance requirements of the sponge midsole, reduce the dosage of the high-priced foaming agent, and further reduce the raw material cost; then in actual production, regeneration Which foaming agent is generally used in the rubber sponge midsole. What problems should I pay attention to when using it 1JLYY814?
1. Characteristics of commonly used foaming agents in the midsole of reclaimed rubber sponge
The foaming agent H is dinitrosopentamethylenetetramine. It is a milky yellow powder at room temperature. It has strong pore-forming ability, easy dispersion and simple and safe operation. It is the most commonly used hair in the reclaimed rubber sponge foam sole. Foaming agent. In the actual operation process, when the foaming agent H is selected for the foaming of the reclaimed rubber sponge, the dispersibility is good, the gas generation amount is large, the foaming efficiency is high, and the generated nitrogen has low permeability to the rubber compound, and can be effective. Prevent the collapse of the sponge midsole during use; the decomposition temperature of the blowing agent H can be adapted to the vulcanization temperature of the compound when the foaming aid is used.
2. Recycled rubber sponge mid-bottom foaming system cooperation skills
The decomposition temperature of the blowing agent H is about 200 ° C, but it will decompose when exposed to acid during the reaction. Therefore, when the reconstituted rubber sponge foaming midsole formula contains stearic acid, the foaming agent H is mixed with stearic acid. The decomposition temperature is reduced from 200 ° C to 130 ° C, and the use of slightly acidic compounding agent can exert the maximum effect; when the foaming agent H is used alone, the cell diameter is fine, and it can be used together with alum and soda to obtain a medium-sized cell. The ratio of blowing agent H, alum and soda is controlled at 11:25:45.
3. Process condition setting when using foaming agent H in reclaimed rubber sponge midsole
(1) Control vulcanization temperature: When foaming agent H is used together with stearic acid, it can be uniformly foamed at 110 °C. However, in order to ensure sufficient vulcanization of the rubber in the reclaimed rubber sponge, the vulcanization temperature needs to be increased to 123- Around 140 °C, it will not affect the foaming performance of the sponge midsole, and can further improve the comprehensive performance of the reclaimed rubber vulcanizate.
(2) Controlling the feeding sequence: when the foaming agent H is used as the main foaming agent in the middle of the reclaimed rubber sponge, the gas generation amount is large, the decomposition heat is large, and the problem of poor dispersion is easy to occur, so that the foaming effect and quality of the reclaimed rubber are affected, so The foaming agent needs to be added in advance and carefully handled in a sponge foam sole with a large thickness.
(3) Thin pass: When using the reclaimed rubber to produce the sponge foaming midsole, the thinning is first carried out after the addition of the blowing agent H, and then the kneading operation is carried out, which can effectively avoid the delamination of the reclaimed rubber sponge compound.
The foaming agent H is the most commonly used foaming agent in the reclaimed rubber sponge foaming midsole. It can be combined with other foaming auxiliaries to prepare cost-effective sponge compound with good performance and low price, but it needs to be selected in the actual operation process. A variety of foaming auxiliaries to reduce the decomposition temperature of the blowing agent H to adapt to the vulcanization temperature, improve the comprehensive index of reclaimed rubber sponge midsole.