Scorched core but normal surface appears in PU flexible foam

The surface of large flexible foam blocks is normal, but the core is found scorched yellow when cut open. Surface defects directly affect the appearance quality and service performance of the product, particularly evident in transparent products. This defect affects the appearance quality of the product, reducing the market competitiveness of the product.

(1) Process factor: Foam has extremely poor thermal conductivity, This factor affects the '2079851475616104453 and final quality of the product. (2) Temperature parameter aspect: When the core temperature is highest and oxygen is present, oxidative degradation accelerates, which may cause thermal degradation of the material or runaway reaction rate, destroying the internal structure of the product. (3) Mold aspect: Insufficient mold surface finish or poor maintenance. (4) Process aspect: Improper temperature or pressure parameters affect surface molding quality. (5) Material aspect: The shrinkage or rheological characteristics of the resin formulation affect surface replication accuracy.

(1) Implementation measure: Limit the maximum block thickness, Develop a specific operation plan based on actual production conditions, and verify the implementation effect. (2) Implementation measure: Actively cool the core after foaming (water or air cooling), Develop a specific operation plan based on actual production conditions, and verify the implementation effect. (3) Formulation adjustment: Reduce the amount of water (exothermic reactant)., Adjust gradually and verify the effect, ensuring that other performance indicators of the product are not affected. (4) Preventive measure: Establish sound process control standards and a quality inspection system, and regularly review process data for continuous optimization.

Surface defects are the result of the combined action of mold condition, process parameters, and material formulation; it is necessary to systematically investigate each factor and optimize accordingly.