Polystyrene-based elastomer TPE-S
1 TPE-S concept
TPE-S is a type of thermoplastic elastomer obtained by modifying SBS (polystyrene-butadiene-styrene block copolymer) or hydrogenated SBS - SEBS as the base material. The TPE-S elastomer modified with SEBS is customarily referred to as TPE and the TPE-S elastomer modified with SBS is referred to as TPR (unless otherwise noted below, TPE refers to the TPE-S class, not the broad TPE thermoplastic elastomer concept).
2 Basic properties of TPE-S elastomers
TPE-S elastomers have in common the thermoplastic processability of plastic and the elasticity of rubber, and have a comfortable elastic feel due to the ability to adjust hardness.
2.1 TPE type TPE-S, the surface is sub-surface, the appearance of transparent, translucent or natural color of the round or cut pellets. The general hardness range is Shore 0-100A, density 0.88~1.2g/cm3. TPE has good aging resistance, excellent chemical stability, and temperature resistance of -50~80 degrees Celsius.
2.2 TPR class TPE-S, the surface is bright, the appearance is transparent, translucent or natural color of the round grain or cut grain. The general hardness range is Shore 0-100A, density 0.88~1.2g/cm3. TPR is less resistant to aging and chemical stability than TPE, with a temperature resistance of -50~60 degrees Celsius and poor hydrolysis resistance. The temperature is higher, or in the high temperature of the water is easy to sticky. However, TPR is easy to stick to glue and easy to match with bright colors, so it is widely used in toys and shoes industry.
3 Microscopic interpretation of special physical properties of TPE-S elastomer
TPE-S materials contain hard styrene chain segments and soft butadiene chain segments, which give the materials the hardness of plastic (making them stiff and wear-resistant) and the elasticity of rubber (giving them a comfortable soft touch). The hard styrene chain segment is embedded in the soft butadiene segment, giving the TPE-S material elasticity and elastic recovery properties without deformation.
4 The main processing and molding methods of TPE-S elastomers
TPE-S elastomers can be easily processed and molded by conventional processing methods such as injection molding (including single-material injection molding and dual/multi-material injection molding), extrusion, calendering (lamination), blow molding, etc. TPE elastomers can also be molten into a liquid state, then poured into a predetermined mold and molded to cool.
5 Main application areas/uses of TPE-S elastomer
5.1 Single material applications
Direct injection molding to produce soft rubber toys, luggage accessories, cushioning and shock absorbing parts. Take advantage of the easy processing, good softness and elasticity of TPE material to meet the customer's use requirements.
5.2 Double material and multi-material applications.
TPE-S is popular in dual-material and multi-material applications. Covering a layer of TPE-S with comfortable handfeel can make the products more contemporary, and its comfortable touch and excellent physical properties are well received by consumers. TPE/TPR can be adjusted to a variety of physical properties and hardnesses, allowing designers to play with unlimited design inspiration. Applications: tool handles, sports equipment, wheels, electronic materials, daily necessities, etc. In the actual application process, because the feel of TPE is better than TPR, double material injection molding is mostly used TPE, if you consider the surface brightness of the product, if you need to spray oil / spray paint, TPR material must be used.
5.3 Food contact apparatus class.
TPE-S is comfortable to touch, non-slip, easy to match with colorful colors, easy to play design inspiration, make life more colorful. Applications: tableware handles, tableware spoons, forks, lids, non-slip coasters, refrigerator ice compartments, etc.
5.4 Medical devices
TPE-S meets the trend of green environment protection and medical food hygiene, excellent chemical resistance, good touch feeling, increase the functionality and comfort of the products. Application cases: medical tubes, disposable infusion sets, anti-drug masks, bottle stoppers, ear wash balls, etc.
5.5 Auto parts category
TPE-S material can withstand high and low temperature (-50-80℃), excellent fluidity, oil resistance, good flexibility, excellent environmental protection, to meet the customer's demand for products with high weather resistance. Application examples: tire cushion, handle, steering wheel, dust cover, etc.
5.6 Extruded products
TPE-S has good UV resistance and chemical resistance, easy extrusion process, it is a new ideal material to replace traditional rubber and PVC. Application cases: earphone cable, USB cable, cable, building sealing strip, door and window adhesive strip, anti-crash buffer strip, etc.
5.7 Extra soft products
TPE-S meets the requirements of human skin contact hygiene and is a recognized green material. Highly transparent, high tensile, high extension and soft touch (skin-like intimate touch) are greatly sought after by consumers. Experience the intimate soft touch and careful care brought by TPE-S material. Application examples: extra soft soft toys, female breast enlargement pads, adult products, etc.
6 Comparison of the difference between TPE-S (TPE/TPR) and PVC
6.1.The basic components of TPE/TPR and PVC soft rubber--
TPE/TPR soft rubber is made of rigid SEBS/SBS (polystyrene-butadiene-styrene block copolymer) as the main base material, with the addition of softening oil, filler and other components.
fillers and other components.
PVC soft rubber is made of polyvinyl chloride as the main substrate, with the addition of softeners (plasticizers), anti-stabilizers and other components, with rubber elasticity.
It is a composite soft rubber material with rubber elasticity.
6.2. Basic characteristics of TPE/TPR and PVC soft rubber
TPE/TPR soft rubber is transparent, semi-transparent and natural color granule, specific gravity 0.85~1.2g/cm3, temperature resistance -50-80 degrees Celsius, with
It has the elasticity and soft touch of rubber, hardness range Shore0-100A, good resistance to general chemicals, gasoline resistance, temperature resistance, hydrolysis resistance is a little worse.
TPE/TPR soft rubber has a special aromatic smell when burning, the material can be glued, the surface can be sprayed with oil, screen printing.
PVC soft rubber can be made into transparent, semi-transparent and natural color granules, specific gravity 1.1~1.4g/cm3, temperature resistance -40-80 degrees Celsius.
PVC is divided into hard PVC and soft PVC. Hard PVC has high strength and is used to produce structural materials. Usually, the soft PVC refers to the soft PVC
PVC soft glue is used to improve the processability and ductility of PVC materials by adding plasticizers (commonly phthalates) to reduce the hardness of PVC.
Acid and alkali resistance, good chemical stability, non-flammable, burning with an unpleasant chlorine smell.
6.3.TPE/TPR and PVC soft rubber environmental performance comparison -
TPE/TPR - Due to the good thermal stability of SEBS/SBS, the material used in the production of TPE/TPR soft rubber, and no other toxic and harmful components are introduced in the modification process.
Therefore, TPE/TPR soft rubber meets ROHS, REACH, PAHS, NP, EN71 environmental testing standards, and the selection of high-quality raw materials can achieve FDA food-grade standards.
PVC - Due to the poor thermal stability of PVC resin, it is difficult to process, so plasticizers and heat stabilizers are usually introduced. Currently most PVC
still use phthalates (DEHP and others in the series) as plasticizers. Phthalates are recognized as toxic substances, and human exposure and inhalation can increase the risk of cancer.
They are recognized as toxic, and human exposure and inhalation increases the risk of cancer. According to some medical studies, PVC plasticizers may cause chronic diseases such as scleroderma, cholangiocarcinoma, and other diseases.
（In 2004, a team of Swedish and Danish scholars found that PVC plasticizers commonly used in the manufacture of PVC were more likely to cause cancer.
In 2004, a team of Swedish and Danish researchers found that the phthalate esters DEHP and BBzP, commonly used in PVC, were strongly associated with allergies in children.
Anti-stabilizers added during the production and processing of PVC can introduce heavy metals such as lead (Pb) and cadmium (Cd). Therefore, it is difficult to meet ROHS, REACH, EN71 environmental testing standards.
6.4. Comparison of the use of TPE/TPR and PVC soft rubber -
TPE/TPR soft rubber application fields-- environmental protection toys (can be sprayed oil screen printing), auto parts, medical supplies, seals, daily necessities, sports equipment, wire
cables, shoe soles, etc.
Application areas of PVC soft rubber - traditional toys, pharmaceutical industry, soft fittings, seals, wires and cables, packaging industry, etc.