PMP Introduction
PMP scientific name Poly 4-methylpentene-1 monomer 4-methylpentene-1 original color Poly 4-methylpentene-1 is a highly crystalline transparent plastic with a specific gravity of 0.83, the lightest of all plastics. It has a low surface hardness and is non-toxic. Its light transmittance is between that of plexiglass and polystyrene. Combustion characteristics It can burn, and continues to burn slowly after leaving the fire, with molten dripping. Advantages The light transmittance of TPX does not change with changes in processing conditions or product thickness, so it is suitable for making transparent products. It has high rigidity, exceeding polypropylene at above 100°C and exceeding PC at above 150°C.
PMP material is a polymer of 4-methylpentene (4-methylpentene-1) produced by Mitsui Chemicals, Ltd. of Japan. TPX is its trade name, and its chemical name is Methyl pentene copolymer, referred to as PMP. Mitsui Chemicals, Ltd. is the world’s only TPX manufacturer; density: 0.82-0.83; water absorption: 0.01%; melting point: 240℃; Vicat softening point 160℃～170℃; shrinkage: 1.5%～3.0%; light transmittance: 90%～92% (the only crystalline polymer among the currently commercialized high-transparency resins).
PMP characteristics
PMP material (high temperature resistance, clear and transparent, high melting point, chemical resistance, acid resistance, alcohol resistance, impact resistance):
⒈Comparison at high temperature: quite high elongation at break, impact strength, excellent creep resistance (high rigidity); a. Exceeding PP above 100℃;
b. Can be used for one year at 130℃;
c. Exceeding PC above 150℃;
d. Can be used for 100 hours at 180℃.
⒉ Electrical insulation: (no polar group in TPX molecule)
a. Dielectric strength: 65KV/mm (better than PTFE and propylene);
b. Dielectric constant: 2.12 (PTFE dielectric constant is 2.0~2.1);
⒊ Chemical resistance: acid, alkali, edible oil; (very low water absorption: extremely high tolerance to water and water vapor)
⒋ Hygiene and safety: non-toxic, in line with US FDA certification;
PMP has better electrical insulation than polypropylene. It is resistant to acid and alkali, chemical corrosion, organic solvents, and stress cracking. It does not have the tendency of other transparent materials to stress crack when used by detergents.
PMP plastic can be sterilized by boiling at 130℃ for 400 times without fogging, and can withstand 50 times of hot air sterilization at 160℃ for 1 hour, and sterilization at 200℃ or above. It can also withstand ethylene oxide and radiation sterilization.
Disadvantages Poor environmental resistance, easy oxidation, degradation by radiation after light, and yellowing when heated.
Applicable Transparent medical equipment, microwave tableware and ordinary tableware.
PMP plastic also has good fiber-forming properties and a wide source of raw materials. Therefore, some people call it “poor people’s nylon”.
Injection molding characteristics PMP is a crystalline polymer with a clear melting point. It can generally melt when heated to 235℃; during injection molding, the general use temperature is 260℃–300℃.
PMP materials do not absorb water and generally do not need to be dried. Sometimes, for product quality, they can be dried at 60°C for 30 minutes to 1 hour to remove the floating water in the raw materials. The shrinkage rate of PMP materials is 22‰.
PMP application
Currently, the annual usage of PMP in the world is about 6,000 tons, mainly in the European, American and Japanese markets. In the past, the Taiwanese industry was not familiar with TPX materials, and the main reason for using TPX was usually specified by foreign manufacturers. Therefore, a few years ago, the usage of PMP in Taiwan was not large, with an annual usage of about 10 tons, and its uses were limited to microwave tableware, transparent cosmetic containers and medical equipment.
However, with the progress of Taiwan’s electronics industry, Taiwan’s PMP plastic usage has grown significantly in recent years. TPX’s release and temperature resistance make it an excellent mold material for epoxy resin limb packaging. In 2000, Taiwan used about 90 hectares of PMP to manufacture LED packaging molds. In the electronic packaging industry, some heat-resistant release papers or films are often used. PMP release films are favored because of their excellent temperature resistance.
In 2000, the Taiwanese industry used about 50 hectares of release film. In addition, the dielectric constant of PMP is very low, so some TPX is used to make high-frequency connectors. Therefore, the current annual usage of PMP in Taiwan is about 150 metric tons, and it is estimated that the usage will continue to grow in the future.
⒈ Beakers, culture dishes, incubators (transparency, chemical resistance, water vapor permeability);
⒉ Cosmetic containers, bottle caps (flavors) (they do not have plastic odor and will not interfere with the original aroma);
⒊ Microwave lunch boxes, food containers (non-toxic, good temperature resistance, no microwave absorption);
⒋ Electronic and electrical parts, LED mold strips, coated cables (insulation, extrusion grade);
⒌ Medical equipment: endoscope tubes, syringes (sanitation);
⒍ Oven appliances (high temperature);
⒎ Film (extrusion grade).
