Analysis on the poor adhesion of liquid silicone wrap product

First, liquid silicone adhesive (composite injection molding) difficulty

 

With the popularity of the application of liquid silica gel, the liquid silicone rubber (composite injection molding) process is also more and more, but the liquid silica gel is particularly difficult to bond other materials due to its surface inertia. Therefore, how to use the coating (composite injection molding) process in the preparation of both soft and hard products involving liquid silicone/plastic substrates has become a problem. Although there are also some surface treatment such as applying primer, using ultraviolet treatment and other methods to treat the substrate surface, but these methods on the one hand more cumbersome, followed by product yield and other losses, in fact, if the process is strictly controlled, the realization of liquid silicon and plastic adhesive good bonding can be better achieved.

 

Second, liquid silicone adhesive preparation

 

① Select a hard rubber material with suitable temperature resistance to ensure that the material can not be deformed when the liquid silicone is packaged twice.

 

② Based on the selection of a shot material, find the matching glue. Because of the different grades of a shot of hard adhesive material, and the same glue does not necessarily match the bond. Therefore, we provide a product to the glue supplier, and deploy the glue that matches and can bond well.

 

③ Choose a reasonable type of glue (self-adhesive or ordinary glue) according to the actual amount of the product.

 

④ Grasp the physical properties and use methods of glue clearly

 

Third, to ensure that the encapsulation firm method

 

① The surface of the product is clean and dry before the coating

 

As we usually use glue to bond objects need to be cleaned, the cleaning of the surface is also very important for the bonding of the adhesive, of course, it is also necessary to keep the substrate sufficiently and reasonably dry, otherwise dirt and water will seriously affect the bonding effect.

 

② Ensure reasonable molding temperature

 

The molding temperature mainly considers the reaction curing temperature of liquid silica gel, the typical liquid silica gel molding temperature is about 150, liquid silicon often needs to be fully cured at a relatively high temperature, so as to have good bonding performance, so it is critical to maintain the substrate product high molding temperature;

 

③ Brush glue

 

Ensure that the width and thickness of the brushing area are stable and consistent, so that the bonding area in the bonding process will be stable and consistent, and the consistency of the bonding performance of the product is also better.

 

Do not use auxiliaries

 

Liquid silicon itself inert has been close to the product as a release agent, if you add these products will be worse, not conducive to the adhesion of the product, so try not to use internal release agent, external release agent or self-lubricating additives in the substrate, even if these additives may not affect the bonding effect, try not to use.

 

⑤ Product demoulding

 

The curing process of liquid silicon is relatively slow, so even if the liquid silica gel seems to have good bonding strength after the release, it is not necessarily the most complete curing when the mold is opened, so try not to pull the liquid silica gel during the release process, so that it will maintain a good bonding effect after slow cooling.

 

⑥ Post-process cleaning

 

When cleaning the rubber in the post-process, pay attention to training the basic configuration and operation techniques of the operator, and formulate a reasonable post-process SOP to ensure that the surface damage to the product will not be caused during the post-process treatment, resulting in the local stripping of the wrapped silicone product.

 

All in all, if you make silicone products, it often occurs to solve the problem of degumming in the production of silicone products, if you find the right direction, you can't solve the problem to the collapse, if you find the right direction, you can solve it soon. As for how to find the direction and method to solve the problem of degumming, it is nothing more than to find the factors through the man-machine material process, so in the final analysis, as long as the early preparation work is sufficient to ensure that the man-machine material process and other factors are well controlled, the degumming problem can be solved.

Guangzhou S-guangyu Machinery & Equipment Co.,Ltd is a professional liquid silicone rubber(LSR) Injection molding machine manufacturers in China since 2010.We have got more than one hundred patents and serve for more than thousands of customers .if you want to learn more about our machines,please visit our web www.lsrexpert-better.com or contact us:86-13902294163.