Silicone Oil Has Three Functions In The Foam Process- Yancheng Oukai Sponge Products Co., Ltd.

Silicone Oil Has Three Functions In The Foam Process

17 . Nov . 2023

1. Emulsification

Polyether, isocyanate, water, physical foaming agent, catalyst, color and other materials are not compatible with each other because of their different physical properties. Add the right amount of effective silicone oil, you can let them blend together, close contact. It’s like two people trying to fight, only when they can touch each other can the fight start.

2. Stable bubble effect

Under the action of catalyst, the carbon dioxide gas produced by the reaction of water and isocyanate is aggregated to form bubbles and escape under the action of gravity of the reaction system. When the physical foaming agent is added, the physical foaming agent also volatilizes and aggregates into bubbles under the action of reaction heat to escape. If the bubbles cannot maintain a certain stability at this time, it is bound to appear side-by-side and burst bubbles. Once the combined bubbles and broken bubbles are large enough to support the stability of the whole system, then collapse of bubbles will occur and foaming will certainly fail.

3. Homogenizing effect

Bubbles gathered in the foaming process have different sizes. At the end of the foaming reaction and the end of the gel reaction, the presence of silicone oil will make the bubbles of different sizes as normalized as possible, that is, the large bubble becomes smaller and the small bubble becomes larger.

When the gel reaction ends, the bubble is broken and a network structure of open holes is formed.

The molecular structure and amount of silicone oil and the amount of tin have obvious influence on the bubble rupture. If the silicone oil activity is high and the amount is large, then the bubble wall formed will be thick and the surface tension will be large. At the end of the gel, the bubble wine is difficult to break completely, and the liquid on the hole wall is difficult to flow to the sponge meridian immediately, forming a residual film.

When the amount of tin is large, the gel speed is fast, the liquid viscosity on the foam wall increases quickly, and the bubble hole is not easy to burst. Even if it bursts, the liquid on the foam wall cannot be completely transferred to the meridians, and some film will remain.

These films will be reduced in the sponge maturation process, but it is difficult to completely eliminate, so that after the sponge maturation is completely cut, you will see the reflective film distributed on the cutting surface. These films are particularly obvious on the colored cotton, which has a great impact on the product quality, especially the black industrial cotton. Customers are very picky about the highlights.

Iii. Solution

It can be eliminated in several ways.

1, choose relatively low activity of silicone oil and the appropriate amount, so that the foam wall of the late foaming foam is thin, easy to break.

2. Use acid-sealed delayed amine to replace part of T-9, give the gel in the foaming process to T-9, and give the delayed amine to complete the post-ripening. In this way, the viscosity before the bubble wall is broken can be greatly reduced, and the liquid can maximize the flow to the sponge meridian after the bubble wall is broken. Reduce film residue.

3. Add sponge to remove film brightening agent and remove residual film by chemical method.

Based on the principle of interface technology, the use of organosilicon surfactants can reduce the surface tension of some materials, the selection of reactive organosilicon materials, supplemented by advanced fatty alcohol, through reasonable manufacturing process, successfully developed the sponge film removal and lightening agent WM-655, the product has been applied to the production of black sponge, achieved satisfactory film removal effect. Under the condition that the amount of black paste is the same, the residual film is much less than that without removing film agent, and the blackness is obviously higher than that without removing film agent.