Application of talc powder in the field of plastic packing

The main component of talc is hydrated magnesium silicate, which belongs to monoclinal system. The crystal is a pseudo-hexagonal or diamond shaped sheet, usually colorless, transparent or white, but there are also light green, light yellow, light brown or even light red due to the small amount of impurities. Super detail talcum powder filler added to plastics, can significantly increase the rigidity of plastic products and creep resistance, hardness and surface scratch resistance, heat resistance and heat deformation temperature, quite a fineness of talcum powder can improve the impact strength of plastic products. It also has the function of lubrication, which can promote the flow and improve the processing technology of plastics.

The characteristics and application value of ultrafine talc powder in several kinds of common plastic materials will be introduced.

1. Application in polypropylene resin:

Talc powder is often used to fill polypropylene. Talc powder has lamellar structural characteristics of lamellar configuration. The fine talc powder can be used as a reinforcing filler for polypropylene. In modification of polypropylene system, by adding super fine talcum powder concentrate not only can significantly improve the rigidity, surface hardness and heat resistance of polypropylene products creep, electric insulation, dimensional stability, also can improve the impact strength of pp. A small amount of talcum powder is added in the polypropylene can also have the effect of nucleating agent, increase the crystallization of polypropylene, so that the various mechanical properties of polypropylene, and due to improve the crystalline, refine the grain size, also can improve the transparence of polypropylene.

Polypropylene composites filled with 20% and 40% superfine talc powder can significantly improve the rigidity and creep resistance of polypropylene at high temperature, both at room temperature and at high temperature. For example: adding 40% of super laundry powder of polypropylene masterbatch resistance to bending modulus can be increased from 16100 kg/cm2 to 42000 kg/cm2, thermal deformation temperature from 62 ℃ (1.82 Mpa) to 88 ℃ or 121 ℃ to 147 ℃ (0.45 Mpa). For electrical components, the dielectric constant increased from 1.9 to 2.4, and the arc resistance increased from immediate melting to 140 seconds. Therefore, in the automobile industry, polypropylene composite materials with talc masterbatch are used for fan cover, heater cover, conduit, battery heat shield, fluid pump parts, etc. In aircraft industry, used for refrigerator door liner, heater, vacuum pump cover, washing machine agitator; In the electrical industry, it is used for injection molding various instrument cases and electrical components, etc.

2. Application in polyethylene resin:

Talc is a natural magnesium silicate with four granule types: fibrous, laminated, needle-shaped and standard (cryolite). But only layers are used in industry. The layered sandwich structure of talc, each layer has certain water resistance and high chemical inertia, so it has good chemical corrosion resistance and slip resistance. Polyethylene filled with it can be used as engineering plastics with good chemical corrosion resistance and fluidity. It can be filled with polyethylene as engineering plastics, and can compete with ABS, nylon and polycarbonate. Filling polyethylene with polyethylene can improve the following properties: improve toughness, flexural modulus and torsion modulus; Improve flexural strength; To reduce the creep tendency under normal temperature and high temperature; Improve the thermal temperature and dimension stability; Improved deformation and warping, but also lower thermal expansion coefficient; Improve thermal conductivity; Improve the surface hardness and finish of moulding parts; Increase the mechanical strength of polyethylene.

For example: use superfine talcum powder filler injection grade hdpe composites, in addition to the above performance has improved significantly, this kind of composite materials tensile strength increases, increased when adding 10% to the maximum, adding 30% when still can keep the original strength, impact strength increases slightly.

For polyethylene blow film, the superfine talcum powder is better filled than other fillers, easy to form and good technology. Moreover, this kind of film can make oxygen transmittance is reduced 80%, especially suitable for packaging oily food, such as peanuts, beans, long-term oil, metamorphism: this kind of film can make water vapor transmittance is reduced 70%, has the very good moisture resistance, is suitable for underground geotechnical wrappings, can also be applied to packaging such as ham, sausages, cheese and other food.

3. Application in polystyrene resin:

Unmodified level general polystyrene is amorphous polymers, its hard and brittle, but it has a good performance, aging resistance and high dimensional stability, the disadvantage is that high brittleness, sensitive to environmental stress cracking. The addition of ultrafine talc powder can improve the impact toughness, adjust the rheology, increase the disturbing modulus and increase the tensile yield strength. For example, if 40% ultrafine talc masterbatch is added, the disturbing modulus increases from 23800kg/cm2 to 58800kg/cm2, and the tensile strength increases from 336kg/cm2 to 385kg/cm2.

Summary: overall, talcum powder particles due to the special lamellar structure, crystal morphology and the chemical properties and the most commonly used filler calcium carbonate, so the talcum powder as polymer filler is still has an irreplaceable role and advantage. If talc enterprises can make full use of ultrafine and modification technologies, it is believed that the market is promising.

Talcum powder