How to Select the Suitable TPE Material for ABS Encapsulation
Selecting the suitable TPE material for ABS encapsulation requires a comprehensive consideration of various factors. Here are some key points to consider:
Material Compatibility:
Solubility Parameter: According to polymer chemistry, two polymers have good compatibility when the difference in their solubility parameters (SP) is less than 0.5. The closer the solubility parameters of TPE and ABS, the better the encapsulation bonding effect and the less likely it is to delaminate or peel.
Polarity Matching: ABS is a weakly to moderately polar plastic. To ensure good encapsulation, the TPE material should also have a certain degree of polarity or its polarity should be adjusted by adding modifiers to enhance the bonding strength with ABS. For example, adding polar enhancers or compatibilizers such as TPU or SEBS-g-MAH to the TPE formulation can improve the compatibility between TPE and ABS.
Hardness Requirements:
Generally, the hardness range of TPE used for ABS encapsulation is between 30 and 90A. If a soft touch is required, such as for handles or grips, a lower hardness TPE can be selected. If higher support and wear resistance are needed, a higher hardness TPE should be chosen.
Testing Confirmation: When selecting TPE hardness, it is best to request samples from the supplier for actual testing to ensure that the hardness meets the design requirements of the product. For example, produce sample parts and perform bending, compression, and other tests to observe the deformation and recovery ability of the TPE material and determine if its hardness is suitable.
Flowability:
Injection Molding Process Adaptability: The flowability of the TPE material is very important for encapsulation molding. A TPE with good flowability can better fill the mold cavity during the injection molding process, especially in complex structures and thin-walled areas of ABS-encapsulated products, ensuring the uniformity and integrity of the encapsulation layer. Insufficient flowability may lead to incomplete encapsulation, lack of material, and other problems.
Temperature Sensitivity: Understanding how the flowability of TPE changes at different temperatures is also critical. In actual production, it is necessary to adjust process parameters such as injection temperature and pressure according to the flowability characteristics of TPE to ensure that the material's flowability is in the optimal state.
Functional Properties:
Abrasion Resistance: If the encapsulated product will be subjected to friction and abrasion during use, such as tool handles, a TPE material with good abrasion resistance should be selected to ensure the product's service life. The abrasion resistance index can be obtained by checking the material's relevant test reports or consulting the supplier.
Weather Resistance: For ABS encapsulated products that are exposed to outdoor environments or harsh conditions for long periods, such as outdoor tools and automotive parts, the TPE material should have good weather resistance, including resistance to ultraviolet rays, aging, and high and low temperatures. For example, selecting TPE materials with added antioxidants and light stabilizers can improve their weather resistance.
Safety: If the encapsulated product is used in areas that come into contact with the human body, such as children's toys and medical devices, the TPE material must comply with relevant safety standards and regulations, such as RoHS, REACH, and FDA. Ensure that the material is non-toxic, odorless, and harmless to the human body.
