Industrial products in the production of the pursuit of the lowest temperature, the shortest curing time. When it is considered that the vulcanization time is too long, it is often to increase the accelerator or increase the vulcanization temperature, but this is actually wrong.

1, because the vulcanization temperature depends on the variety of rubber, such as the best vulcanization temperature of natural rubber is 145-148 degrees, the best vulcanization temperature of styrene-butadiene rubber, butyl rubber and butadiene rubber is 148-153 degrees, and the vulcanization temperature of silicone rubber is 170-175 degrees. In actual operation, the temperature difference of the filter should be adjusted to add about 3-5 degrees on this basis. The setting of the curing temperature should not be changed. Such as changes will certainly affect the physical properties of rubber. At the same time, there will certainly be such and such problems in the production process.

2. The setting of vulcanization time is set according to the thickness and operation requirements of the product. Because the thermal conductivity of rubber is very poor. The thicker the product, the longer the vulcanization time. The setting of vulcanization time should be considered to filter different products and set different vulcanization time. Too long fluidization time of thin products is a waste of productivity and energy. Thick products vulcanization time is too short, the outside coke is not ripe seriously affect the quality.

3. In order to improve the vulcanization speed, there are generally two methods: heating, and the other is to increase the amount of accelerator or switch to super accelerator. For example, products with low physical property requirements can be filtered. But it's hard to control. Because according to the theoretical calculation of each increase of 10 degrees vulcanization time is reduced by less than half of the time. If the temperature is increased, it should also be calculated how much temperature should be increased. It is a common method to adjust the fluidization speed by increasing or decreasing the accelerator. It must be adjusted by increasing or decreasing the accelerator after setting the temperature and time. It is important to adjust the accelerator because the solubility of the accelerator and sulfur in the rubber is very small. When it exceeds its solubility, it will run out and spray frost. Moreover, physical properties should also be greatly changed.

Practice has proved. Generally, the amount of accelerator for ordinary products should be as little as possible. Adding or subtracting accelerators should not be done proportionally. The second should be added. The third accelerator improves the activation performance. In this way, the blooming problem of the accelerator can be effectively controlled, so as not to affect the physical properties and stability of the product. Increased productivity cannot be fully filtered from reducing the vulcanization time. General manufacturers are from the operator to increase the number of operating mold to test the filter.

Blindly increase the accelerator, increase the temperature, to improve the yield has the following hazards.

1, physical impact.

2, there is the possibility of frost spray

3, the rubber is easy to self-sulfur.

4. The rubber material has high viscosity, poor vulcanization performance and is not easy to operate.

Excellent formula should be selected to adapt to the rubber curing temperature of the best upper limit, the least amount of accelerator, the shortest curing time. Consider these three main points.

At present, there are many rubber factories in China that produce molded products with a thickness of less than 8MM. The combination of four DM-M-TMTD-D accelerators is a very good formula. Its advantages are flat vulcanization curve, long scorch time, easy control and difficult frost spraying.

DM is the first accelerator to determine the entire vulcanization process, and the amount of the four accelerators is the most, and it is determined by a certain physical property of the rubber. In general, it should not be increased or decreased.

The amount of M a little less it can improve the curing speed, as a second accelerator. In the vulcanization process, it and DM are both mutually inhibited and activated, and this combination plays a key role in the control of vulcanization speed. And is a kind of plasticizer, is conducive to the plastic solution of rubber molecules.

TMTD is the third accelerator. It is a super accelerator used to speed up the vulcanization speed. Generally, the dosage does not exceed 10% of DM. Otherwise, it is easy to self-sulfur if too much rubber is used, and the physical properties of rubber will decrease. Accelerator D itself is a medium-velocity accelerator. Single when the vulcanization speed is not fast, generally used for thick products. However, it is an alkaline accelerator, which can be activated quickly when combined with DM and M, and the vulcanization speed is accelerated immediately. It is used as an auxiliary accelerator, mainly as an activator, and is used to control the vulcanization speed. Generally not more than 20% of DM. It is well adjusted together with TMTD when regulating the sulfur rate.

TMTD will decompose to M at high temperature and rapidly activate D/DM. The solubility of different accelerators in rubber is different, and the use of such multiple accelerators can reduce the amount of single promotion. It plays a key role in the control of accelerator blooming in rubber products. The adjustment of the vulcanization speed is also greatly facilitated. Different physical properties, different scorch, different curing time, the application of different accelerators. Blindly increasing the vulcanization temperature to speed up the vulcanization is one of the most stupid practices.

With the best curing temperature, reasonable use of accelerator collocation, still can design a curing speed, good physical properties of the formula, in the daily production, to the pursuit of rapid vulcanization in 1. M/H or M/TS can be used for less than 5 points, and DM/D/TMTD can be used for those requiring general scorching and faster sulfur rate below 3 points, and at 4 points. DM/M/TMTD can be used in combination for 5 minutes or less. Similar uses are numerous. The optimal vulcanization time is not determined casually either. It is calculated according to the thickness of the product and vulcanization temperature. I will not talk much about what is in the calculation formula book. It can also be estimated by practical experience. T90 time is used for less than 6MM and T90 +(m-6) minutes is used for more than 6MM. Can produce an excellent product in addition to a reasonable excellent formula. In the vulcanization time, temperature, pressure and production process factors are equally important.