How to prevent scorching in the process of using a rubber mixing mill?

 

Scorching is essentially the accumulation of heat and time on the rubber in the process of using a rubber mixing mill and is an early vulcanization phenomenon of the rubber, which can also be called the thermal history of the rubber. The scorch time is often used to measure the ease of scorching of the rubber, and the longer the scorch time, the less likely it is that early vulcanization will occur in the process.

Here is the content list:

• How to determine rubber scorch?
• What is scorch time?
• What are the methods to prevent scorching?
• How to deal with scorching?

How to determine rubber scorch?

1. Scorched rubber, after vulcanization, the product is not bright (matte), the surface has obvious wrinkles, the surface is not flat, very brittle, and easy to crack.

2. The surface of burnt rubber is also uneven and has hard lumps. And scissors can’t cut the burnt rubber.

3. The scorched rubber can be measured by doing the Menny scorch test.

4. See figure: scorched part of the hard lump of protrusion. Try to cut to see, that the hard block is scissors that can not be cut.

What is scorch time?

The scorching characteristics of rubber are usually expressed by the Menny scorching time ts at 120°C. The t10 or ta1, ta2 on the vulcanization curve can also be measured by the vulcanizer, and t10 is the scorching time. It is the time required for the torque to reach 10%. The scorching time of the rubber material is related to its process, rubber accelerator process conditions, rubber hardness and rubber material back to use, and other factors. Generally, the scorching time is 10-20min for soft rubber, 20-35min for most rubber (excluding hard rubber with a high filling or high processing temperature), and 35-80min for hard rubber with high filling. steeply increase.

What are the methods to prevent scorching?

1. The rubber compounding machine of the rubber additives formula design should be appropriate and reasonable. As far as possible, such as a variety of accelerators with the way.

2. For the rubber mixing machine cooling measures for rubber, through strict control of the machine temperature, roll temperature, and adequate cooling water circulation, so that the operating temperature does not exceed the critical point of scorching.

3. The management of semi-finished products of rubber material, ensure that each batch of material has a flowing card to follow, follow the principle of “first in first out” storage, and stipulate that the longest time of each car material stays in the storage and does not exceed. In addition, keep the warehouse well ventilated.

How to deal with scorching?

In the rubber mixing machine on the thin pass, and the roll temperature is low, the loading capacity should be small, can not wrap the roll, packing, beating roll, parked for 24 hours, and then mixed into the good material to use, mixing amount 15-20%. Scorch serious in the thin pass when adding stearic acid and oil softeners to destroy its cross-linked structure.

Through the above on the rubber mixing mill scorching phenomenon of the judgment method, prevention methods, and treatment of the introduction, I believe that you have been able to better prevent the use of rubber mixing mill scorching phenomenon. If you are in the rubber mixing mill business, you can consider Qingdao Huicai Machine Manufacture Co., Ltd.’s cost-effective products.