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Affected by the construction conditions, equipment, process and environment, polyurethane rigid foam will have various abnormal phenomena during the construction process, which will eventually cause product quality problems. The various situations are now analyzed as follows:
1, A, B material does not foam after mixing: 1 material temperature is low; 2 two groups of distribution ratio is not allowed 3 leakage plus catalyst; 4B material quality is inferior; 5 leakage plus blowing agent.
2, polyurethane rigid bubble shrinkage: 1A material composition, so that the strength of polyurethane rigid foam caused by shrinkage; 2 spray gun material mixture is uneven, spray air is too small, or material viscosity is too large; 3 curing too fast, more formation Closed hole; 4 gas thermal expansion and contraction deformation.
3, polyurethane rigid foam crisp: 1B material too much; 2 too much water; 3 working surface temperature is too low; 4B material acid value, containing more impurities; 5 flame retardant added too much.
4, polyurethane rigid foam is too soft, too mature: 1B material composition is small; 2A material tin catalyst is too small; 3 temperature, material temperature, blanking work surface temperature is low.
5, polyurethane rigid foam collapse: 1 foaming gas produced too fast, should reduce the amount of amine catalyst in the A material; 2 foaming agent failure or alkaline; 3 catalyst failure or leakage, should be added to the tin catalyst in the A material ; 4 The acid value of the raw material is large.
6, polyurethane rigid bubble hole coarse: 1 foaming agent failure or leakage; 2 more water (foaming agent or polyether moisture); 3A, B material mixing and mixing uneven; 4B material purity is low, containing total chlorine or The acid value is high; 5 gas is generated faster than the gel.
7. Polyurethane hard foam cracking, or heartburn: 1 material temperature is high; 2 catalyst excess; 3 once pouring amount is too large, foam is too thick; 4 water is used as foaming agent when adding too much; 5 material has metal salt impurities .
8. Polyurethane hard foam shedding: 1 The wetness of the sprayed working surface is large, so that the reaction is not completely sufficient, the bottom layer of the foam is crispy, brittle, and powdery; 2 the sprayed working surface is unclean, oily, too dusty
9, polyurethane hard foam escape smoke: 1 catalyst dosage is too high; 2 polyether hydroxyl value is too high; 3 material temperature is too high.
From the above reasons, it is known that, in addition to objective factors, there are many factors involved in the composition of A material. In actual production, the adjustment of viscosity, milking time, foaming time, curing time, etc. is mainly to adjust the A material.
This article is reproduced from Langfang Zhongyang Insulation Materials Co., Ltd.: http://