ASTM, originally known as the American Society for Testing and Materials, is an international standards organization founded in 1898 that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services.
ASTM has a dominant role among standards developers in the USA, and claims to be the world's largest developer of standards. Using a consensus process, ASTM supports thousands of volunteer technical committees, which draw their members from around the world and collectively develop and maintain more than 12,000 standards.
Underwriters Laboratories Inc. (UL) is an independent product safety certification organization. UL develops product safety standards and evaluation methods, and performs evaluation tests in order to standardize the functions and safety of materials, equipment, components and tools.
UL does not guarantee the products tested by UL, but permits products that comply with safety regulations through a test of samples whose shapes and contents are identical to other products in the same line, to carry a UL certification mark. UL manages lists of products with UL marks and provides them to users so that they can trace the testing history of materials and products
Haze occurs on the surface of or in a transparent plastic, and is the level of diffusion of incident light into a transparent plastic. Haze is expressed in a ratio of the diffused light transmittance to the total light transmittance
The chemical formula of talc is Mg₃(Si4O10)(OH)₂ and it is a monoclinic crystal system. In general, talc is lamellar and has a scale-like structure. Talc is very soft with a greasy feel, and also has curvedness. Talc which has irregular fracture and basal cleavage is called steatite or soapstone. Talc has a hardness of between 1.0 and 1.5, and a specific gravity of between 2.7 and 2.8. Talc is a byproduct of talc schist and serpentinite
A homopolymer is a polymer compound with one type of monomer. Polypropylene is a single combination of propylene and is widely used since it has excellent mechanical properties such as high crystallinity, tensile strength and stiffness.
In the process of deforming an object by applying stress, stress increases proportionally to strain. Beyond the proportionality limit, stress stops increasing and reducing at some point, and then strain increases rapidly. This point is called the yield point.
Flow marks are molding defects that remain on the surfaces of molded products in the mold cavity and occur in the manufacturing process of injection molding. In general, when the filling speed of a melted material is low, a partial solidification or hardening of the material occurs. This phenomenon occurs on the surfaces of molded products. If the injection speed or injection volume of an injection machine is insufficient compared to the sizes of the products, and the melting temperature of materials is low, flow marks occur.
A plastic material is any of a wide range of synthetic or semi-synthetic organic solids used in the manufacture of industrial products. Plastics are typically polymers of high molecular mass, and may contain other substances to improve performance and/or reduce costs. Monomers of plastic are either natural or synthetic organic compounds.
There are two types of plastics: thermoplastics and thermosetting polymers. Thermoplastics are the plastics that don't undergo chemical change in their composition when heated and can be moulded again and again; examples are polyethylene, polystyrene, polyvinyl chloride and polytetrafluoroethylene. Thermosets can melt and take shape once; after they have solidified, they stay solid. The raw materials needed to make most plastics come from petroleum and natural gas.
Propylene is an unsaturated organic compound with the chemical formula C3H6. It has one double bond, and is the second simplest member of the alkene class of hydrocarbons. Propylene is colorless with a weak but unpleasant smell at room temperature. It has a melting point of 185 ℃, a boiling point of 47.7 ℃ and a specific gravity of 0.5139, and undergoes reactions such as polymerization and oxidation. Propylene is present in cracked gas in petroleum fraction and is made via dehydrogenase of propane or by decomposition. It is used as a raw material for polypropylene and is used to produce isopropyl alcohol as a petrochemical material, acetone, propylene oxide, propylene glycol, allyl alcohol, glycerol, acrylonitrile as well as acetone and dodecyl benzene via the cumene process.
Polypropylene is a thermoplastic polymer obtained from the polymerization of propylene. Polypropylene has a melting point that ranges from 164 to 170°C, a specific gravity of between 0.90 and 0.91 and a molecular weight that ranges from 100,000 to 200,000. Propylene is made together with ethylene when decomposing naphtha in a petrochemical factory. Polypropylene is isotactic and thus has an arrangement of methyl groups, in order, in the same direction. Polypropylene is composed of only carbon and hydrogen and thus has an electrical characteristic which is as good as that of polyethylene. It is used in wide variety of applications, including packaging film, stretch tape, synthetic fibers, pipes, consumer products, toys, industrial components, containers and more.
A polymer is generated through the polymerization of molecules and is a compound composed of repeating structural units. A polymer contrasts with a monomer and has a high molecular weight. 'Polymer' is a compound word made up of 'poly' (many) and 'mer' (unit) and refers to a synthetic compound with a large molecular weight. Polymers are obtained from the polymerization of monomers. In general, polymers containing a molecular weight of between 10,000 and 20,000 are called low polymers. Polymers containing a molecular weight of between 20,000 and a few million are called high polymers. There are two types of polymerization reaction: addition reaction and polycondensation reaction. The molecular weight of a polymer becomes double that of a monomer in an addition reaction. Simple molecules are separated and the molecular weight of a polymer does not become double that of a monomer in a polycondensation reaction. The number of repeating units in a molecule is called the degree of polymerization. There are 2-monomer units and 3-monomer units according to the degree of polymerization. A monomer unit with a value for a degree of polymerization which is less than 20 is called an oligomer. Polymers with high degree of polymerization are called high polymers, and are also called high molecular compounds. Homopolymers have a single type of repeating unit and are also referred to as straight polymers. Copolymers have more than two types of repeating units in a molecule
A pellet is a resin compound with additives, and its diameter is between 2 mm and 5 mm. Pellets are spherical, cylindrical and cubic shaped tablets. Pellets are pelletized by a pellet machine or extrusion for molding operation and then they are cut into small pieces
When light strikes the surface of an object, some of the light is reflected and the rest is absorbed or passes through. Transmitted light is classified as parallel light transmittance and diffused light transmittance. Measures for the transmittance of plastics are light transmittance (a ratio of total light transmittance to incident light) as a measure for brightness, and haze (a ratio of diffused light transmittance to total light transmittance) as a measure for clarity.
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons can be classified as chain type hydrocarbons and ring type hydrocarbons according to how the carbon atoms bond together. Chain type hydrocarbons include paraffinic hydrocarbon (or methane hydrocarbon, general formula CnH2n+2), olefinic hydrocarbon (or ethylene hydrocarbon, general formula CnH2n) and acetylenic hydrocarbon (general formula CnH2n-2). These hydrocarbons have two types of bonding structures: a straight-chain structure and a side-chain structure. A chain type hydrocarbon is sometimes called an aliphatic hydrocarbon. Ring type hydrocarbons usually belong to aromatic compounds or ring type compounds, but also sometimes belong to other aromatic compounds. A hydrocarbon is the basis of organic compounds and can be found in crude oil, natural gas, rubber or terpene. Generally hydrocarbons are the raw materials for naphtha, gas oil, ethane, C₃LPG and C₄ LPG.
Modulus of elasticity is the deformation of an object within elastic limits. It is a ratio of the tensile, bending, compression, shear and twisting stress applied to an object to strain. Its unit is kgf/m㎡. The greater the modulus of elasticity, the less deformation occurs
