Surface silver streaks on microcellular foamed products

Silver-white fine streaks appear on the surface of supercritical fluid microcellular foamed products. Surface defects directly affect the appearance quality and usability of the product, and are particularly evident in transparent products. This defect affects the appearance quality of the product and reduces the market competitiveness of the product.

(1) Gas removal aspect: dissolved gas rapidly escaping from the product surface producing surface stretch marks; gas retention forms internal defects affecting product compactness. (2) Mold aspect: insufficient mold surface finish or poor maintenance. (3) Process aspect: improper temperature or pressure parameters affecting surface molding quality. (4) Material aspect: resin formulation shrinkage or rheological characteristics affecting surface replication accuracy.

(1) Parameter adjustment: reduce depressurization/cooling rate after foaming; appropriately reduce pressure under the premise of ensuring product compactness to avoid defects caused by insufficient pressure. (2) Parameter adjustment: appropriately increase mold temperature to slow gas escape; it is recommended that each adjustment range be 5-10°C, while monitoring product quality changes to avoid new defects caused by excessive temperature. (3) Implementation measures: use rapid cooling for surface setting., formulate specific operation plans based on actual production conditions and verify implementation effects. (4) Preventive measures: establish a sound process control standard and 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; each factor must be systematically investigated and targeted optimization performed.