TPE|TPR products cracking is what happened?

　　Answer: mainly by three reasons to cause TPE products crack!

　　1、Cracking

　　Material by air, ozone oxidation, aging cracking caused by. Some low hardness, thin size of the sheet products (especially SBS substrate), the

　　Exposed to the air, the surface will be cracked after a few days!

　　2、Solvent action cracking

　　Some toys that need to be sprayed with oil, as well as some softer children's shoes soles, sometimes the phenomenon of product cracking will occur during the processing. The reason for the occurrence of cracks is that the amount of ink or glue used is too much, or accumulate on the surface, just the surface of the product is corroded resulting in cracks. For this reason, according to the different TPE|TPR materials, attention should be paid to the choice of adhesive, as well as attention to the amount of adhesive and the uniformity of the surface spraying.

　　3、Stress cracking

　　TPE|TPR products because of structural design, certain reasons, such as fusion marks, uneven product thickness and structure with obvious angle or curvature changes, easy to stress concentration, gap effect, which leads to product cracking.

　　What happened to the skinning and delamination of TPE product sprue?

　　Answer: The internal reason is bad material compatibility. The external reason is that the location of the gate has a strong shearing effect. The skinning and delamination at the gate is mainly due to the lack of material compatibility and the strong shearing effect.

　　Many TPEs based on SEBS system are alloy materials, if the compatibility of the system is not enough, when encountering special injection molding product cases (such as flow length ratio is large, need higher injection speed), it is easy to have skin delamination at the gate position. In the gate position, the flow direction and rate of the melt will change sharply, which is similar to shear effect, and is a great test for the system uniformity of TPE melt. The larger the injection rate and the larger the flow length ratio, the more obvious the shearing effect. If the TPE components are not compatible enough, it is easy to lead to different phase structure and component delamination and skinning.

　　Improvement: TPE blending system should simplify the component distribution ratio and enhance the compatibility of the system. Try to use high pressure and low injection speed when molding. If possible, design a more reasonable location of the inlet port to reduce the product flow length ratio.