Take you in-depth understanding of TPE raw materials
Source：德创化工Time：2020-01-06Hits：1968
1.TPE is just a material?
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"How much is your TPE per ton?" Hearing such questions, we will feel that TPE is only a kind of material, and its performance and price are relatively fixed, but in fact, TPE contains many types, such as TPR, TPV, etc. There are many types, and it is not a kind of material. Its performance and use are also different, and its natural price will also be different.
2.TPE can replace PVC perfectly?
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Compared with PVC, TPE does not contain halogen, o-phenylene plasticizer and heavy metals. TPE is a new type of environmental protection polymer material. It has both the processing properties of thermoplastic and the physical properties of vulcanized rubber, and has better low temperature resistance, more comfortable and smooth touch, better wear resistance and skid resistance. These characteristics make people think TPE can replace PVC perfectly.
As far as the actual situation is concerned, in some fields without strict environmental protection requirements, PVC materials still occupy a dominant position by virtue of their price advantages, and it takes a process for TPE to completely replace PVC.
3.TPE secondary injection molding (encapsulation) does not adhere well, it must be a material problem?
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Encapsulation is an important application way of TPE materials. When the problem of incomplete adhesion of TPE encapsulation occurs, some customers may first think of the problem of material. However, incomplete adhesion of encapsulation is not entirely a problem of material. Inadequate temperature used in injection molding will also lead to incomplete adhesion. Different TPE materials and hard plastic, mold and product structure of encapsulation are all factors to be considered in setting molding temperature.
4.TPE is food grade?
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Many manufacturers publicize that their products are food-grade TPE, but the food-grade standard is only a general concept, and there are different testing standards for different materials. The testing requirements of FDA for food-grade materials are distilled water and n-hexane, and the testing standard is 21CFR177.2600. At present, few TPE manufacturers can pass both tests at the same time in the market.
02 Several Major Causes of Fuel Injection Problem
Solvent problem
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TPE integrates the characteristics of soft glue and hard glue. If there is a problem during oil injection, it is often due to an error in solvent selection, resulting in burning and deoiling.
1. Burning glue-mainly occurs on rubber parts with TPE hardness greater than 70 degrees. Due to the strong solvent used, the surface will be seriously corroded and traces will be left when contacting the rubber parts, that is, burning glue occurs.
2. De-oiling-mainly occurs on rubber parts with TPE hardness less than 70 degrees. Because the solvent used is too weak, the paint cannot be firmly attached to the surface of the adhesive. Once the soft rubber piece is deformed, the paint itself cannot follow the shape change, causing the surface layer to separate, causing deoiling.
Die design
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If the surface of the product is uneven, such as the doll's face, burning glue will often occur. The reason is that solvent usually accumulates in the uneven part, and the chance of burning glue naturally increases.
Excessive composition of nozzle material
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Manufacturers usually add different proportions of nozzle materials in their production. However, the nozzle material will reduce the chemical resistance of the glue piece. When the solvent that the pure raw material product can bear is too strong for the product containing the nozzle material, the glue burning occurs.
TPE with PP or pe
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Some TPE contains PP or PE components to enhance adhesion. However, PP and PE are chemicals with strong chemical resistance, so the finished TPE products have poor oil injection performance.
Solution
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1. Select the appropriate paint. Under normal circumstances, manufacturers are not recommended to prepare their own paints and should seek supplies from professional paint suppliers.
2. Try to design the material level as flat as possible. If the design is limited, paint should be diluted as much as possible to reduce the influence of glue burning due to solvent accumulation.
3. The quantity of nozzle material shall be below 30%.
4. TPE containing PP and PE components should be avoided if there is oil injection process.
