LDPE N125Y《

At the beginning of its establishment, the French company was based on the business philosophy of honesty and mutual benefit, and won the trust and support of our customers. Currently, we have set up branches in Shanghai, Zhejiang, Dongguan, Hong Kong and other places to meet the needs of our customers. Demand, so far, we have cooperated with many brand raw material suppliers including DuPont of the United States, B SABIC, BASF of Germany, LANXESS of Germany, Bayer Br of Germany, Polyethylene Co., Ltd. of Japan, Asahi Kasei Co., Ltd., Chi Mei of Taiwan, Taihua of Taiwan, etc. Establish long-term cooperative relationships and ensure the quality, reliability and stability of materials with first-hand supply. The following is a brief introduction to the company's products. Please call us for prices and parameters! It is a crystalline thermoplastic plastic with a clear melting point of ~°C. Its properties are closest to metal and is generally called plastic steel. It has the advantages of high mechanical strength and rigidity, the highest fatigue strength, environmental resistance, good resistance to organic solvents, and strong resistance to repeated impacts. It has a wide range of properties. Operating temperature range ℃ ~ ℃, good electrical properties, good restorability, self-lubricating, wear resistance, good dimensional stability, advantages and disadvantages, prone to thermal decomposition if exposed to high temperature for a long time during processing, no self-extinguishing properties, poor acid resistance, poor molding shrinkage, large use electronics Electrical appliances, washing machine, juice machine parts, timer components, car handlebar parts, electric window parts, industrial parts, mechanical parts, gear handles, toy screws, we solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. B main features are? Low water absorption? Excellent dimensional stability? High stiffness and strength? Outstanding thermal aging properties? High color stability at high temperatures? Excellent weathering resistance? Good high sliding properties? Good chemical resistance sex. It is a highly crystalline thermoplastic plastic with a melting point of ~°C and a relatively fast crystallization rate. Advantages: Stable mechanical properties, tensile strength and tensile modulus similar to nylon, small friction coefficient, self-lubricating, low water absorption, electrical properties, excellent dimensional stability, good chemical resistance, excellent oil resistance, disadvantages: low ℃, ℃ under load The impact strength is poor, and glass fiber reinforcement is generally used for B purposes. Electronic appliances, fuse breakers, electromagnetic switches, return transformers, household appliances, handle connectors, car door handles, bumpers, distributor covers, fenders, wire shields, rims Covers, industrial parts, fans, keyboards, fishing gear reel parts, lampshades, we solemnly promise that all the raw materials sold by our company are genuine and original. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. The basic properties are outstanding toughness and moisture content. Excellent chemical and oil resistance. Outstanding wear and abrasion resistance. Almost all scores automatically go off. This flame retardant rating is rated certified. Outstanding long-term heat resistance at long-term continuous maximum temperatures ranging from C to 150 C. Grades of reinforced fiberglass and other materials that provide superior modulus of elasticity and strength. Provides low gasoline penetration and excellent gas barrier properties. We solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Outstanding balanced mechanical properties. Outstanding toughness in b Moisture content. Outstanding chemical and oil resistance. Outstanding wear and abrasion resistance. Almost all levels are automatically extinguished. This flame retardant rating is rated for the US. Excellent long-term heat resistance over long-term continuous maximum temperature range to ℃. Grades reinforced with fiberglass materials provide superior elastic modulus and strength. Low permeability provides gasoline and excellent gas barrier properties. We solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. It is an amorphous thermoplastic. Advantages: High strength and elastic coefficient, high impact strength, wide operating temperature range, high transparency and free dyeing, high fatigue resistance, good weather resistance, good electrical properties, tasteless and odorless, harmless to the human body, hygienic and safe in molding Low shrinkage rate, good dimensional stability, shortcomings, poor design of molded products, prone to internal stress problems. Applications: Electronic and electrical switches, home appliance casings, signal tubes, telephones, automobile bumpers, distributors, safety glass, industrial parts, camera bodies, machine tool casings, safety helmets, diving goggles, safety lenses. Solemn commitment All the raw materials sold by our company are genuine materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Added B, excellent mechanical properties, high temperature resistance, outstanding impact strength and excellent dimensional stability during application. Applications Automotive Industry Car front end, instrument panel, console box, glove box lid, door, wheel cover and hood, defrost, rear view mirror housing electronic and electrical display housing, fax machine housing, laptop housing, cellular phone housing, fax machine and copy frames, drive trays and main frames, relay housings, connectors, switches, housings, industrial parts and other helmet housings, junction boxes, power tool housings, industrial spools, manifold boxes, power tool parts, gears, water meters Shell solemnly promises that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Resins offer designers a wide range of materials with exceptional properties for a wide range of applications. Typical uses for thermoplastic polyurethanes are automotive dashboards, casters, power tools, sports equipment, medical devices, and various applications in extruded films, sheets and configurations. The production equipment is/is certified. The most important advantages are high wear resistance, high elasticity, r hardness range, good low temperature impact strength, flexibility over a wide temperature range, freedom from plasticizers, excellent resistance to oils, greases and many solvents , good resistance to weathering and high-energy radiation, pleasant tactile properties and thermal bonding, easy to color, easy to recycle, excellent anti-corrosion special grades, we solemnly promise that all the raw materials sold by our company are genuine materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Choose from transparent, translucent, opaque, or custom colors in varying levels of melt flow and heat resistance. For those special applications, there are also UV-absorbing UV and UV-transmitting grades. Properties Amorphous polymer, light transmittance, thermal denaturation temperature between Window glass signs, optical lenses, hard contact lenses, auto parts, solemnly promise that all the raw materials sold by our company are genuine and original. Buyers who choose logistics or express delivery, please first confirm whether there is resin in the local area that has the characteristics of high gloss, impact resistance, electroplating, etc. of the logistics or express delivery. Generally used in daily necessities such as household appliances and toys. At present, the main types of general-level products are: It has high flow characteristics. It is generally used for molding products such as large household appliances, motorcycle trailer shells, and thin meat moldings. It has low flow characteristics and is suitable for extruding plates and pipe fittings. Generally used for lining suitcases, B pipes and large containers in refrigerators. It has heat-resistant properties and is suitable for products with high temperature requirements. It is generally used in heating appliance casings, hair dryers, heaters and automotive components such as instrument panels. The company has established long-term cooperative relationships with many companies based on the principle of customer first and integrity first. We solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Applications: Electronic and electrical, micro electronic component packaging, connectors, connectors, sockets, coil skeletons, trimming capacitors, and fuse bases. Mechanical instrument pump casing pump wheel gear pulley universal head seal gasket flange counter level meter flow meter components. In the automotive field, temperature sensor, carburetor evolver, carburetor pump, seat base, water tank and water chamber. Household appliances, electric fans, microwave oven stands, clothes dryers, coffee cookers, rice cookers, hot air cylinders, hair curlers, air conditioner compressors, we solemnly promise that all raw materials sold by our company are genuine and original. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Product Features High temperature electrical/electronic assembly can withstand assembly process operations, including lead-free reflow soldering. Excellent thermal aging properties, maintaining inherent properties at high temperatures. Excellent flowability in thin walls, complex shapes. It has excellent dimensional stability, low molding shrinkage and extremely small thermal expansion coefficient, comparable to metal. During molding, the molecular chains are aligned in the direction of flow, producing a self-reinforcing effect as if the molecules themselves reinforce them, resulting in extremely high strength and elastic modulus. Excellent chemical resistance. Molding speed cycle is extremely fast. Excellent creep resistance. Flame retardant. It has excellent dielectric properties in a wide temperature range. We solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Business outlets. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Product Features: High tensile strength, high toughness, stronger impact toughness, the product is not easy to warp, good flow properties during molding, and good electrical insulation. Typical applications can be used in ignition components, coil covers, relay seats, gears, various pump casings, vacuum cleaner components, storage equipment components, screw sockets. We solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Properties are generally available in blends with other polymers, exhibiting exceptional moisture resistance, high dimensional and thermal stability, good flame retardant and high electrical resistance properties. Polyphenol Oxidase* was first formulated by GE. Features: Wide operating temperature range to ultra-rigid, excellent impact resistance and fatigue resistance, excellent insulation properties, low dielectric constant and low dielectric loss, low tangent water absorption, stable molding size, excellent flame retardancy and self-extinguishing performance, low specific gravity, low molding shrinkage, Suitable for precision parts. Excellent mold release and fluidity, wide molding temperature range. We solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. It is designed for applications requiring good elasticity, appearance and sealing properties. This grade is shear dependent and can be used on conventional thermoplastic processing equipment, injection molding, extrusion or blow molding. It is polyolefin based and fully recycled. It has excellent temperature resistance, aging resistance, ultraviolet and ozone resistance, excellent bonding properties with polyolefin, and small permanent compression deformation. The material has strong rubber feel, excellent electrical properties, good colorability, and excellent Dynamic fatigue resistance and high tear resistance. We solemnly promise that all the raw materials sold by our company are genuine and original materials from the original factory. Buyers who choose logistics or express delivery should first confirm whether there is a local business outlet for this logistics or express delivery. After the raw materials arrive at the factory, please do not open the outer packaging. You should first carefully check whether the outer packaging of the raw materials is intact and whether the raw material model matches the raw material model you ordered. After the goods are delivered, please check them as soon as possible. If you find a large number of packaging damage and leakage of raw materials during the logistics process, please ask the logistics personnel to issue a certificate and save it, and contact us within hours. If you cannot receive it in time after shipment, please contact us in time. Product Features? Among the nylon series resins, it has the lowest water absorption?? Dimensional stability will not cause dimensional changes and mechanical strength reduction due to water absorption?? High heat resistance,? Temperature of lead-free solder. ??Good fluidity, suitable for thin meat forming. ??Low gas, less likely to contaminate and corrode the mold than other nylon resins, extending the use of the mold. ??The crystallization speed is fast and the cooling time is short. ??In high-temperature environments, the mechanical strength and rigidity decrease less, and the bonding line strength and recyclability are good. High performance polyamides offer unparalleled performance and value for automotive and electronics applications. Highest mechanical properties, high temperatures, excellent wear resistance, low friction, excellent flow, ease of processing and exceptional design. Degree of freedom? Polym-xylylene adipamide, the English abbreviation, generally referred to as nylon, is a special high-barrier nylon material. Although its barrier properties are slightly worse than those of A and B, its barrier properties are not affected by temperature and humidity, which is especially suitable for use in high temperature and humid situations. In today's general trend of barrier packaging and replacing steel with plastic, nylon has become one of the most eye-catching new plastic varieties. R series resin has higher mechanical strength and modulus than other engineering plastics. ?It is therefore versatile and can be used as a replacement for metal, especially in more complex structural components that need to withstand heavy stress. ?Currently, R has been widely used in various industries, such as automobiles, electrical appliances, electronic machinery, construction, etc. ?Features??The advantage of high strength and high modulus in a wide temperature range??The molding dimensional stability is higher than that of polyamide, and the low water absorption rate gives it the advantage of high strength??The thermal expansion coefficient is low, equivalent to that of alloys ??High resistance to oils and organic solvents??Small shrinkage, not easy to deform??The surface remains glossy even when reinforced with glass fiber. Features: Minimum hygroscopicity. Parts display the greatest dimensional stability under changes in humidity conditions. ?Exceptional impact and notch impact strength, even at temperatures well below freezing, excellent resistance to grease, oil, fuel, hydraulic fluids, various solvents, salt solutions and other chemicals ?Excellent resistance to stress cracking, including Injection molded or embedded metal parts for encapsulation Good wear resistance Low sliding friction coefficient in dry, running conditions against steel, polyethylene terephthalate, polyacetal, and other materials Noise and vibration damping properties Superb resistance Fatigue Performance Cyclic Loading Conditions at High Frequency? High Processing Applications/Uses? Blister Packaging? Blood Therapy? Blown Film? Credit Card? Debit Card? Deodorizing Packaging? Packaging Equipment? Drug Release? Electronic Packaging? Prefabricated Boxes? Flexible Packaging? Food packaging? Furniture/furniture decoration? Game cards? Gift cards? Identity documents? Four components? Four, containers? Medical experiments? Lamination? Phone cards? Plastic cards? Rigid medical packaging? Shrink film? Logo? Smart card? Suction & Drainage? Toys/Sporting Goods? Oil Pipes? Writing Instruments The resin provides excellent elasticity due to its glass transition temperature of about ℃. This characteristic of polymer materials and its high strength and low spread absorbs low tides, and it is an excellent finish that makes metal materials good. Alternative candidates for many regional markets, high elastic tension coefficient up to high strength r number up to more rarely spread? When the deformation is insufficient, the spirit is more, some results are the same as the glass fiber content, facing the excellent resistance of engineering most polymer floors The completion of first-class products with excellent appearance is further strengthened by the high glass fiber content, which is easy to process and the input b. Even the high glass fiber content makes the production of dispersed and complex construction projects good, stable, low shrinkage and high reproduction, so that the tension is kept low and the time is tight. , achieve slow water absorption, semi-aromatic, low water absorption, slow water absorption, relatively, implementation of project formation and implementation, humidity more sensitive chemical properties, resistance to various complex chemical product characteristics, optical properties, optical components, low birefringence, electrical insulation, chemical resistance Properties: Acid-base cooking oil has very low water absorption, extremely high tolerance to water and water vapor, hygienic and safe, non-toxic, and complies with US certification. Applications: Film sheet industrial parts blowing pharmaceutical packaging eyeglass parts including lens frames. Polyetherimide Polyetherimide resin is an amorphous thermoplastic resin, referred to as. It has outstanding high temperature resistance, high strength, high modulus and wide range of chemical resistance. Features Inherent flame resistance Electrical/electronic applications, low smoke emission Internal components for the aircraft/aerospace industry, Long-term heat resistance R up to ℉°C Food service Bakeable, Dimensional stability High temperature lighting condensers and reflectors, High temperature strength and Modulus for automotive under-the-hood applications, hydrolytically and chemically stable medical device trays, wave soldering and steam soldering stable utility cookware. and grade application vessels and fasteners feature low density, among the engineering plastics, the plastic is one of the mildest, has proven resistance to hydrolysis, vapor resistance, excellent acid and alkali resistance, good forming, good flowability, good repeatability, Electrical characteristics: Very small loss, good tracking resistance characteristics??Wide operating temperature range??Super rigidity, impact resistance and fatigue resistance??Excellent insulation properties, low dielectric constant and low dielectric loss tangent??Low water absorption rate , Stable molding dimensions? Good flame retardancy and self-extinguishing performance? Low specific gravity? Low molding shrinkage, suitable for precision parts? Excellent mold release and fluidity, wide molding temperature range. Main features? Mechanical properties, Is an ideal metal replacement? Excellent high temperature performance. Outstanding electrical properties. Excellent resistance to fuels, glycols and chemicals. Excellent dimensional stability, low moisture absorption. Low vapor transmission rate. Typical Applications Automotive? Air Induction? Electrical/Electronics? Fuel Systems? Heating and Cooling? Coatings, Composites, Additives? Cookware? Personal Care, Small Appliances? Lawn & Garden, Power Tools? Electric? Contactors, Switches? Automotive Components Electronics Components of the product Faucet assembly Bearing holder B Overview of uses: Washing machines, vacuum cleaners, printers, toys, stationery and other accessories. It can also be used to manufacture transparent plates and lamps, which are widely used in various fields of national production. Our company operates *American DuPont SABIC Innovation〔 *Netherlands*?SABIC Innovation〔Transparent, translucent, opaque, with fiberglass, auto parts, plugs and other raw materials*American DuPont SABIC Innovation〔?SABIC Innovation 〔?SABIC Innovation〔 *ExxonMobil SABIC Innovation〔Toughened nylon,,,,,tubing, packaging coating*France Arkema SABIC Innovation〔SABIC Innovation〔SABIC Innovation〔 Toughening, hot melt adhesive, shoe glue, adhesive materials imported original package * South Korea Engineering Plastics SABIC Innovation [? SABIC Innovation [ * DuPont of the United States,? SABIC Innovation [ * Supply? DuPont of the United States high toughness injection molding grade *Supply? The U.S. DuPont super toughness* supplier? The U.S. DuPont tough and high viscosity* supplier? The U.S. DuPont high viscosity plus Teflon fiber* supplier? The U.S. DuPont high viscosity* supplier? The U.S. DuPont super tough grade* supplier? The U.S. DuPont wear-resistant Grade* supplier? American DuPont plus fiber* purpose automotive SABIC [machine tool SABIC [instrument interior parts SABIC] bearings SABIC [fasteners SABIC] [gears SABIC] Spring leaf SABIC [Pipe SABIC] Conveyor belt accessories SABIC [Electric water cooker SABIC] [Pump casing SABIC] [Drainer SABIC] [Faucet, etc.* Korea? SABIC Basic Innovation〔*Germany's Bayer supplies Japan's Idemitsu, South Korea's Samsung, and the United States' raw materials*The United States? ?SABIC Innovation〔 ?SABIC Innovation〔*Japan's Idemitsu SABIC Innovation〔R?SABIC Innovation〔 ?SABIC 〔*Samsung Cheil Wool Saber Basic Innovation〔?Sabot Basic Innovation〔 *«High impact strength, good dimensional stability, colorless and transparent, good colorability, electrical insulation Saber Basic Innovation〔Corrosion resistance Basic Innovation [Good wear resistance] * Optical lighting " Transparent materials used to manufacture large lampshades SABIC [Protective glass SABIC [left and right eyepiece tubes of optical instruments, etc., and can also be widely used on aircraft" * Electronics Electric appliances "Polycarbonate is an excellent ℃-level insulating material, used to manufacture insulating connectors SABIC [coil frame SABIC] tube base SABIC [insulation sleeve SABIC] telephone casing And parts SABIC Innovation [battery shells for miner's lamps, etc.] * High temperature resistance, transparent, opaque, fiber reinforced, flame retardant,,, UV resistance, injection molding, extrusion, general grade * Japan Toray SABIC Innovation [?S