Plastic coating in the current plastic products processing and manufacturing industry can be said to be commonplace, abound. Daily life of the toothbrush, shower head, screwdriver handle, etc., are plastic overmolded typical cases. Although the plastic covering process has been very mature in the industry, but for some contact with TPE plastic material is not much for the user, in the pre-molding process, TPE plastic package is not not uncommon, plastic Bur here to do a brief analysis, I hope to help you.

　　The package is not secure impact factor analysis

　　Factor one material did not find the right

　　Problem Cause Analysis: Some users have just come into contact with a new TPE package plastic products, before not used TPE, not through the network or other channels to do the pre-TPE materials to understand, directly in the acquaintances (generally some not very professional TPE material plastic traders) that casually take a TPE material to try. The result is to try out the package can not be.

　　Suggestions: the first contact with the TPE plastic wrapping materials, it is best to have production and research and development strength of TPE manufacturers to do preliminary technical advice.

　　Knowledge popularization:

　　1 plastic wrapping difficult to analyze

　　Commonly used plastics are ABS, PP, PC, PA, PS, POM and so on. Each plastic, basically have the corresponding TPE coating material grade. Relatively speaking, PP is the best wrapping; PS, ABS, PC, PC + ABS, PE plastic wrapping second, but the wrapping technology is also very mature, the realization of solid wrapping no difficulty; nylon PA wrapping difficulty will be greater, but in recent years the technology has made significant progress. TPE wrapping nylon is no longer imported TPE manufacturers patents, there are at least a few domestic TPE manufacturers can provide Firm package nylon TPE grades; as for polyacetal (POM steel material) of the package, in the industry is still a difficult problem, the imported material Germany Gumbo TCXH series, can be wrapped; domestic plastic Bo, TSE-ADM series can be achieved a good package.

　　2.The main plastic wrapping TPE hardness range

　　PP wrapping: hardness range 10~95A.

　　ABS, PC, PC+ABS overlay: hardness range 30~90A.

　　PS coating: hardness range 20~95A.

　　Nylon PA overmolding: hardness range 40~80A.

　　POM (paraformaldehyde steel) overmolding: hardness range TCXH series 50~80A, TSE-ADM series 60~85A.

　　Factor 2: Mold and product structure

　　A Product structure - thickness and area of overmolding

　　The greater the thickness and area of the product wrapping, the longer the time for TPE to flow in the mold cavity to complete the wrapping, but the longer the time, the greater the decrease in temperature of the rubber material in the flow process in the mold cavity, and the lowering of temperature is not conducive to the wrapping of adhesive bonding.

　　B Product structure--Flow length ratio

　　The greater the flow length ratio, the greater the difficulty of overmolding. In general, it is recommended that the overmolding mold design, the flow length ratio of 1:150 or less. For example, the overmolding thickness of the overmolding layer is 0.5mm, and the maximum overmolding length of the overmolding layer (in the direction of flow) is recommended to be below 75mm. The larger the overmolding flow length ratio, the higher the requirement for TPE material's fluidity and melt strength.

　　Mold design - runner and gate design

　　For some products with large overmolding area or flow length, the size of the flow interface, the location and number of gate design should be considered. the core of TPE overmolding process is: overmolding while it is hot, so some of the design should be conducive to the rapid completion of the TPE overmolding.

　　Mold design--Hot runner

　　For complex product coating structure, if conditions allow, using hot runner molds, will be conducive to the realization of the hot coating, so as to obtain a better effect of the overmolding.

　　Factor 3: Overmolding process

　　A Molding temperature

　　If the overmolding temperature is low, the TPE can not form a fused layer with the plastic to be overmolded. If there is no problem in material selection, but the overmolding effect is not good, you can try to increase the overmolding temperature appropriately.

　　Generally speaking, it is recommended to increase the overmolding temperature to 180~250℃ for PP;

　　Package ABS, PC, PC + ABS, it is recommended to package temperature 180 ~ 230 ℃. Package PC, the temperature is higher than the package ABS.

　　Package nylon molding temperature ranging from 210 ~ 280 ℃, PA66 than PA6D wrapping temperature is high, fiber-added, heat-resistant nylon wrapping temperature is higher. For nylon covering, according to the different temperature resistance of nylon, to match the corresponding TPE grade.

　　For POM, TSE-ADM series, the supplier, Plastic Bo, gives the suggestion that the coating temperature is 175~195℃.