Integral skin foam is a type of polyurethane foam that is widely used in the manufacture of automotive parts, gym equipment, and furniture and other industries related to daily life. However, some problems in the production process are becoming more and more concerned by producers.

Here are some common problems and solutations to share with you:

1.Dark bubbles

Dark bubbles are one of the most common defects of integral skin molded foam, from the appearance, there is only one layer of skin, and there are pores under the skin, some large and some small, and bubbles will bulge by squeezing.

Dark bubbles are usually not visible directly with the eyes, but can only be felt by touching the hands, regardless of size. In this case, the foam is usually torn open to see the result.

Tear off the skin, if the skin is smooth, it means that the air bubbles are not discharged, or the air that is not well discharged in the discharge head of the foaming machine needs to be eliminated by exhausting.

If the cavity under the skin is rough, it may be caused by the foam simmering and blistering caused by fine dust particles in the material. This requires eliminating the source of contamination and identifying conditions that could cause small particles to appear. In some the densities are higher. This occurs when the mold temperature is below 35°C in products that require a fast gel speed.

2.Chicken feet bubbles

Chicken feet bubbles, shaped like chicken feet, without epidermis covering, much like chicken feet on the foam skin.

The main reason is that the reaction speed is too fast in the later stage, that is, the gel speed is too fast, and it is necessary to reduce the amount of gel catalyst and reduce the amount of crosslinker accordingly to reduce the gel speed in the later stage.

3.Desquamate

In molded integral skin foams, peeling is often the case at the edge of the mold's clamping line or inserts. This is especially true in all-water achoncine foaming. 

The reasons are that the molding ratio is too low; the mold temperature is too low; the activity of modified isocyanate is low.

4.Pinholes

On the surface of the epidermis, especially around the mold exhaust, it is easy to have small pores, which are difficult to find without looking closely.

The main reason for this phenomenon is that the moisture content is too high in the foaming system mixed with water. In an all-water system, it can be caused by the release agent not drying out. In humid climates, air compressors often have a lot of moisture, when blowing the mold with compressed air, or when using compressed air to spray the inner paint of the mold, the water droplets are brought into the mold, and the water is difficult to clean up, and it is easy to appear pinhole-like.

5.Bulging

Full-water autocrust foaming, especially easy to bulge for thicker products. This is mainly caused by the lack of overall porosity and late maturation of the all-water foaming system.

Generally, it can be solved by adding an appropriate amount of open-pore polyether or increasing the catalyst in the later stage.

Qichen provides customers with customized Blend Polyol for integral skin foam, and also provides a series of technical support.