Polyurethane flexible foam is a kind of flexible polyurethane foam with certain elasticity, which is the most used polyurethane product in polyurethane products.
Polyurethane soft foam is mostly open-cell structure, with low density, good elastic recovery, sound absorption, ventilation, heat preservation and other properties. Molded soft foam is a foam product that is directly mixed with raw materials and then injected into a mold to foam into a desired shape through a gap method.
How to deal with the problem of easy bonding and peeling of molded soft foam skin?
First of all, it must be clear that the epidermis is related to these processes:
a. The configuration and fluidity of materials: including raw materials, water, and additives, any improper configuration will not work;
b. Mold temperature, material temperature: should not be too low;
c. Mold structure, design and placement;
d.Selection and dosage of release agent, in which more amount will defoam, less will peel;
e. Control the curing time of the product. Insufficient curing (the proportion of B material is too high) or curing for too long can cause peeling;
f. Other complicating factors.
We can adjust by the following points:
1. find the reason in the formula. If the B material has a T/M system, the ratio should be considered and the MDI should be appropriately increased; it is recommended to remove T-9 and add DMEA (dimethylethanolamine); grasp the fluidity of the material.
2. the amount of water and silicone oil should be moderate, generally controlled at about 2.8--3.5, otherwise it will stick to the skin; the amount of silicone oil should not be used too much, otherwise it will peel.
3. check the mold, whether it is clean, whether there is air leakage, and whether the placement position is balanced, otherwise the collapsed bubbles will cause the mucous membrane.
4. the mold temperature and the material temperature, the large difference between the two temperatures is easy to peel and stick. The mold temperature is generally 30 to 50 degrees, and the material temperature is 21 to 25 degrees. The temperature must be adjusted during the season.
In addition, it is recommended to use a delayed amine catalyst to slow down the reaction speed; use a better waxy release agent to reasonably control the product aging time.
