china extruder machine manufacturer Glass fiber is a filler commonly used in engineering plastics. Its main components are silica and other derived metal oxides. The current international mainstream production process is the kiln drawing method; It is divided into alkali-free glass fiber, medium-alkali glass fiber and high-alkali glass fiber; the glass fibers commonly used in engineering plastics are mainly alkali-free chopped glass fiber and untwisted long glass fiber. After adding glass fiber, the engineering plastics will change as follows .
1. Enhance rigidity and hardness, the increase of glass fiber can improve the strength and rigidity of plastic;
2. Improve heat resistance and heat distortion temperature. Taking nylon as an example, nylon with glass fiber is added, and the heat distortion temperature is increased by at least 30°C or more, and the temperature resistance of general glass fiber reinforced nylon can reach more than 220°C;
3. Improve dimensional stability and reduce shrinkage;
4. Reduce warping deformation;
5. Reduce creep;
6. Reduce hygroscopicity.
When the modulus of the product increases, the toughness will decrease; it will have an adverse effect on the flame retardant performance, because the candle wick effect will interfere with the flame retardant system and affect the flame retardant effect; the exposed glass fiber will reduce the gloss of the surface of the plastic product.
The length of the glass fiber directly affects the brittleness of the material; if the glass fiber is not handled well, the short fiber will reduce the impact strength; if the long fiber is handled well, the impact strength will be improved. In order to keep the brittleness of the material from being greatly reduced, it is necessary to choose a certain length of glass fiber.
The fiber content of the product is also a key issue. The industry generally adopts integer content such as 15%, 25%, 30%, 50%, etc. The specific content of glass fiber needs to be determined according to the use of the product.
In order to obtain good mechanical properties and surface effects, the diameter and length of the glass fiber, as well as the surface treatment and glass fiber content during subsequent modification, are all very important!
china extruder machine calcium carbonate products are divided into heavy calcium carbonate and light calcium carbonate. Heavy calcium carbonate is abbreviated as heavy calcium, and English abbreviated as GCC. Because the sedimentation volume of heavy calcium carbonate is smaller than that of light calcium carbonate, it is called heavy calcium carbonate. At present, there are two main processes for industrial production of heavy calcium carbonate, one is dry process and the other is wet process. The dry process produces a lower cost and versatile product than the wet process.
Light calcium carbonate is referred to as light calcium, also known as precipitated calcium carbonate, and English abbreviation is PCC. The main components of lime are calcined limestone and other raw materials to form lime. , and then introduced carbon dioxide, carbonized lime milk to form calcium carbonate precipitation, and finally obtained by dehydration, drying and pulverization. Or first use sodium carbonate and calcium chloride to carry out a metathesis reaction to generate calcium carbonate precipitate, and then dehydrate, dry and pulverize it.
Calcium carbonate is one of the earliest inorganic fillers used to fill and strengthen PP, and the application of micro-scale calcium carbonate has always been in a dominant position. The research shows that the addition of calcium carbonate can increase the impact strength of PP, but the tensile strength decreases, the addition of light calcium carbonate can improve the impact strength and yield strength at the same time, and the PCC treated with stearic acid has a better effect. , Calcium carbonate treated with titanate coupling agent can significantly improve the impact strength of PP.
With the emergence of nano-scale calcium carbonate, china extruder machine manufacturer found that nano-scale calcium carbonate can strengthen and toughen at the same time, and the toughening effect is better than micron-scale calcium carbonate. Studies have shown that the morphology of nano-calcium carbonate is different, and the mechanical properties of composite materials are also very different. Cubic nano-calcium carbonate is beneficial to improve the impact properties of composite materials, while fibrous nano-calcium carbonate can significantly improve the tensile properties of the material. Nano-calcium carbonate can significantly refine PP spherulites and promote the formation of generate.
Glass beads are a new type of silicate material, including solid and hollow. Usually glass beads with a particle size of 0.5-5mm are called fine beads, and those with a particle size below 0.4mm are called microbeads; there are many kinds of microbeads according to different sources, and fly ash glass beads are extracted from fly ash A kind of lightweight micro-spherical material, its main component is silicon dioxide, and it also contains a variety of metal oxides. The fly ash glass beads have the advantages of high temperature resistance and small thermal conductivity. Wear resistance, compression resistance, flame retardant and other properties of the material, and its special spherical surface can also improve the processing fluidity of the material, in addition, its surface gloss is good, which can increase the surface gloss of the product and reduce the dirt adsorption on the surface.
Glass beads are widely used for strengthening and toughening of PP. The research shows that with the increase of glass microsphere content, the tensile modulus, flexural strength and modulus of single- and twin-screw extruded PP/glass microsphere composites all show a linear increase, while the yield strength decreases slightly. ; The fracture strain increases at a low content, and then decreases rapidly, and the impact strength of single-screw and twin-screw extruded materials increases, and increases with the increase of the glass bead dosage within a certain range, and the single-screw extrusion material increases. The impact strength of the extruded material is slightly higher than that of the twin-screw extruded material, and the particle size of the glass beads has a great influence on the toughness of the PP/glass bead composite.
At present, the most widely used and studied silicate minerals are talc, montmorillonite, wollastonite, etc. Among them, attapulgite and zeolite have also received more attention.
Both talc and montmorillonite (MMT) are layered silicate minerals. Talc is a magnesium silicate mineral with a flaky structure. Generally, the finer the particle size, the better the dispersion effect, which can improve the thermal deformation temperature and surface finish of the material; the MMT layer spacing is large, and the intercalation method is often used to prepare PP composite materials. , MMT can form a good intercalation structure in the PP matrix, thereby improving the impact resistance and dimensional stability of PP.
Attapulgite (ATP) is a chain layered silicate. ATP is a natural one-dimensional nanomaterial silicate mineral. Its basic structural unit is a needle-like or short-fiber-like single crystal. ATP can be compounded with polypropylene at two levels of micro-filling and nano-enhancing to improve the mechanical properties of the material. . This new type of short clay fiber overcomes the shortcomings of general glass fiber reinforced resin, such as poor fluidity, rough appearance, and serious wear to processing equipment, so it has high development value.
china extruder machine Wollastonite is a single-chain silicate mineral, usually in the form of flake, radial or fibrous aggregates. Studies have shown that wollastonite-filled plastics can not only improve their mechanical properties, but also can be used instead of glass fibers to reduce costs.
Zeolites are shelf silicate minerals. It has a rich pore structure, and can prepare polypropylene composite materials with strong functionality by adsorbing or loading functional particles to improve the added value of products. Therefore, the development of PP/zeolite functional composites has great potential and has become a hot spot of current research and attention.
The chemical composition of titanium dioxide is titanium dioxide. According to the different crystal forms, there are rutile type and anatase type. Rutile type is the most stable crystal form, with compact structure, and its hardness, weather resistance and powdering resistance are better than anatase type. It is stable to various chemical substances in the atmosphere, insoluble in water, and has good heat resistance. After titanium dioxide is added, it can not only improve the whiteness of the product, but also reduce the damaging effect of ultraviolet rays, improve the light aging performance of polypropylene, and improve the rigidity, hardness and wear resistance of the product, but it is different from crystalline materials such as PP. , PA and other poor compatibility, it is necessary to compatibilize and modify it.