Two-component silicone sealant common problems and solutions

time:2021-01-06 10:12:00source:http://en.scknd.com/news808254.html

There are bubbles in the silicone sealant


Causes of bubbles:

1. When replacing the plastic barrel, the air in the barrel and the surface of the plastic was not drained cleanly, causing air bubbles.

2. Improper use of bottom rubber in the collection bucket.

3. When the sealant needs to be replaced after the sealant is used up, it is not replaced in time, and the glue supply pump has been running idly, so that air is mixed into the supply glue cylinder. After the air is mixed with the sealant, large or small air bubbles are formed.

4. The solvent used for cleaning the gluing equipment is not completely volatilized. When gluing, it adheres to the surface of the sealant, forming pores on the bonding surface of the sealant and the substrate.


solution:

1. After cleaning the gluing equipment, drain more glue to ensure that the solvent is completely evaporated before normal construction.

2. It is recommended that the sealant be replaced in time after use, and the glue pump should not be idling.

3. Open the exhaust valve after changing the barrel, so that all the gas in the pressure plate is exhausted, and a small amount of glue overflows from the exhaust port, and there is no sound of gunshots when the glue is discharged continuously.

Second, the bonding is unstable


reason:

When part of the path of the glue application equipment is blocked or the air pressure is unstable, it will cause abnormal glue output of the glue application equipment, and the ratio of A and B will be unstable. The knot is unstable or the bonding time is prolonged.​​


solution:

1. During the construction process, check the air source frequently to ensure the stability of the air pressure, and clean the glue equipment regularly to make the glue path unobstructed.

2. The mass ratio of components A and B of Zhengzhou Zhongyuan MF881 silicone structural sealant ranges from 11:1 to 14:1, the maximum mass ratio is 12:1, and the volume ratio is about 8.5:1.

3. The bonding with the aluminum profile with the frame is unstable

Reasons for unstable bonding:

1. The selection of profiles does not meet the requirements of the specification - the material or the viscose surface is selected as the material;

2. There is no compatibility test, the glue and the profile are not compatible;

3. The compatibility test profile is inconsistent with the actual profile;

4. There is a big difference between the profiles.

5. The profiles are not clean enough;

6. Improper use of primer;

7. Uneven mixing of glue;

8. The maintenance time is not enough;

9. There is no strict quality control.

4. Group B is separated, analyzed and delaminated, and the colloid solidifies abnormally

Reason for separation:

Component B is mainly composed of curing agent, coupling agent, filler, etc. through physical blending. After a long time of placement or bumpy transportation, segregation and delamination are prone to occur. Do not stir well before use.


solution:

Please stir in the same direction before use.

5. "Flower Maw" appears during the gluing process.

Causes of "flower glue":

1. The pipeline of Group B of the gluer is blocked.

2. The static mixer has not been cleaned for a long time, causing the cured sealant to block part of the path of the mixer, so that components A and B cannot be fully mixed.

3. Different manufacturers have different product performance, and the equipment process parameter settings are also different.


solution:

1. Clean the B component pipeline.

2. Regularly clean the static mixer.

3. Adjust the process parameters of the equipment to ****.

6. The pressure plate cannot be pressed down or the glue turns over when glue is applied.


reason:

1. The size of the packaging barrel and the pressure plate of the glue machine do not match.

2. The diameter of the sealing ring is too large or too small, or the sealing ring loses elasticity due to aging.

solution:

1. Select the packaging barrel that matches the pressure plate of the glue machine or adjust the size of the pressure plate.

2. Replace the sealing ring with a slightly larger diameter or add some lining to the original sealing ring to increase the diameter of the sealing ring.

7. The curing speed is too fast or too slow.


cause:

1. The amount of component B is too large or too small.

2. The gluing equipment is abnormal.​​

3. The sealants of different manufacturers are used interchangeably.


solution:

1. Components A and B should be used in the correct proportion (mass ratio A:B=11:1~14:1).​​

2. Cleaning and maintenance of gluing equipment.

3. The composition of sealant of different manufacturers is different, and the curing system is also different, so they cannot be used interchangeably.

4. After gluing, a period of curing and a period of non-curing appear.


cause:

The pipe of component B of the gluer is blocked, which causes the above phenomenon to be caused by the supply of component B more and more often.


solution:

1. Clean the B component pipeline.

2. Adjust the process parameters of the equipment.

Related tags

silicone,sealant,

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