Causes and solutions of some quality problem​s during rubber mixing

First, the surface is not smooth and rough:

Cause:

1. The film is too thick.

2. The temperature difference between the two rollers is large.

3. The temperature of the two rollers is too low.

Solution:

1. Adjust the roll distance to meet the technological requirements.

2. Add or subtract cooling water to feel temperature.

3. When the roll temperature is low, the roll distance is marked

Second, the product surface has impurities or surface There are powder holes in the cross section of cooked rubber particles

Cause:

1. There are impurities in the filler material used. The filter screen of the rubber is broken when the rubber is being filtered. The rubber material gets into the ground during mixing and tableting, resulting in sand and other debris mixed into the rubber material.

2. The scorch time of the rubber is too short, and the rubber is vulcanized at an early stage.

3. The cooling is not in place when the film is released, which causes the glue to be cooked due to the inability to dissipate heat in the middle of the whole basket of glue.

4. The untreated machine head glue with cooked glue is mixed into the good glue.

5. The temperature of the roller is too high during kneading or tableting.

6. The film thick and thin triangular bags are not operated according to the process.

7. The powder compound is damp, which leads to the high moisture content of the rubber and the difficulty of dispersion

Solution:

1. Check all kinds of fillers used, and if there are impurities or coarse particles in hand, they cannot be used, and they should be returned. When the rubber filter is found, the rubber filtered after the filter screen is broken must be re-filtered. The rubber compound must not get dirty on the ground during operation.

2. Properly adjust the dosage of vulcanizing agent and accelerator.

3. Pay attention to the temperature of the rubber when the film is produced. If the rubber is found to be overheated, put a little less glue in each basket and spread it out to cool it naturally to avoid burning the rubber.

4. Classify and store the rubber for the machine head. The rubber that can be used must be treated with a small amount of anti-scorch agent and stearic acid on the open mill before it can be used.

5. Reasonably control the temperature of cooling water: 50-60 degrees of natural styrene-butadiene, 60-70 degrees of chlorinated polyethylene and EPDM.

6. The roll distance is 1-2mm for 5 times of book pass and 3 times of triangle bag.

7. If there is no drying equipment, it is found that the wet powder compound cannot be used in one case

Three, the plasticity of the rubber is high or low or uneven

Cause:

1. The amount of plasticizer is too large or the temperature during mixing is too high.

2. The proportion of plasticizer is low, and the mixing temperature is low or the thin triangular bag is not in place.

3. The film is too thick and not mixed according to the process

Solution:

1. The amount of plasticizer can not be changed normally, and the temperature of the machine is controlled within the process range.

2. The proportion of plasticizer is reasonable. If the roller temperature is low at the beginning, the roller distance should be smaller and strictly follow the process.

3. Improve the quality awareness of operators and operate according to the specifications of the process.

4. There are many voltage breakdown points in the spark test of insulated wire cores

Cause:

1. Insufficient vulcanization of the insulating rubber, resulting in foaming, flattening and frying of the insulating core.

2. There are impurities in the rubber.

3. The surface of the insulated wire core is scratched or scratched.

4. The insulating rubber is eccentric or the outer diameter of the insulation is too small, and the insulating rubber is too thin.

Solution:

1. Improve the vulcanization system to make the insulating rubber fully vulcanized to meet the standard requirements.

2. Strengthen the management of the filter rubber, and keep the rubber compound clean during the process of adding vulcanization and tableting, and no impurities are mixed in.

3. Remove the mold sleeve to remove impurities or cooked glue in the mold sleeve. 4. Readjust the eccentricity so that the insulation thickness can meet the standard requirements.