Sunday, December 26, 2010

ABS Plastics ( Acrylonitrile-butadiene-styrene )

Molecular  (C8H8·C4H6·C3H3N)n

        The letters ABS identify the family of acrylonitrile-butadiene-styrene.  Common trade names for these materials are Cycolac, Kralastic, and Lustran. They are opaque and distinguished by a good balance of properties, including high impact strength, rigidity, and hardness over a temperature range of–40 to 230°F (–40 to 110°C). Compared to other structural or engineering plastics, they are generally considered to fall at the lower end of the scale. Medium impact grades are hard, rigid, and tough, and are used for appearance parts that require high strength, good fatigue resistance, and surface hardness and gloss. High impact grades are formulated for similar products where additional impact strength is gained at some sacrifice in rigidity and hardness. Low-temperature impact grades have high impact strength down to –40°F (–40°C). Again, some sacrifice is made in strength, rigidity, and heat resistance—continuous use up to about 200°F  (93°C), and a 264lb/in2 (2Mpa) heat distortion temperature of around 215°F (102°C). Impact strength is about comparable to that of medium impact grades, but strength, modulus of elasticity, and hardness are higher. At stresses above their tensile strength, ABS plastics usually yield plastically instead of rupturing, and impact failures are ductile. Because of relatively high heat resistance provide ABS plastics with good dimensional stability. ABS plastics are readily processed by extrusion, injection molding, blow molding, calendering, and vacuum forming. Resins have been developed especially for cold forming or stamping from extruded sheet. Extruded shapes including tubing and pipe. ABS plate parts are now in wide use, replacing metal parts in the automotive and appliance field.

Applications:

     ·   TV set, radio, and vacuum cleaner housings
     ·   Telephones (body)
     ·   Refrigerators (internal box)
     ·   Air conditioner grill
     ·   Containers
     ·   Helmets
     ·   Luggage tote trays
     ·   Grills for hot air systems and pump impellers


ABS High Rigidity

Molding Properties

       ·    Drying temperature                                        : 70~80°C
       ·    Drying time                                                    : 2hr
       ·    Injection forming cylinder temperature            : 200~260°C
       ·    Injection molding tool temperature                  : 50~80°C
       ·    Injection molding pressure                              : 560~1760kgf/cm­­2
       ·    Compression molding temperature                  : 160~180°C
       ·    Compression molding pressure                       : 0.7~5.6kgf/cm2
       ·    Molding shrinkage rate                                   : 0.4~0.9%
       ·    Specific gravity                                               : 1.03~1.06density
       JIS            : K6911,K7122
       A.S.T.M   : D792

Mechanical Characteristics

       ·    Tensile strength                                               : 400~530kgf/cm2
       JIS            : K6911,K7113
       A.S.T.M   : D638
       ·    Tensile elongation                                           : 3.0~20.0%
       ·    Compressive strength                                     : 127~879kgf/cm2
       JIS            : K7208
       ·    Flexure strength                                              : 773~914kgf/cm2
       JIS            : K7203
       ·    Izot impact strength                                         : 10.9~33.7kgf/cm2
       JIS            : K7110,K7111
       ·    Rockwell hardness                                          : R107~115
       JIS            : K7202
       A.S.T.M   : D785

Thermal Characteristic

       ·      Heat resistance temperature (continuous)                   : 71~93°C
       ·      Deflection temperature under load
               a)                  Bending stress18.6kgf/cm2                  : —
               b)                  Bending stress 4.6kgf/cm2                   : 99~108°C
       JIS            : K7206,K7207
       A.S.T.M   : D648

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