What is the business scope of the plastics industry?

1, synthetic resin:

Synthetic resin refers to the high molecular compound synthesized by chemical and physical methods, taking coal, calcium carbide, petroleum, natural gas and some agricultural and sideline products as the main raw materials, first preparing low molecular compounds with certain synthesis conditions. The properties of these compounds are similar to natural resins, but they are superior to natural resins. Such as synthetic resin dentures.

The content of synthetic resin accounts for 40% ~ 100% in all components of plastics, which plays an adhesive role and determines the main properties of plastics, such as mechanical strength, hardness, aging resistance, elasticity, chemical stability, photoelectricity and so on.

2, plastic additives:

Plastic additives The main purpose of adding additives to plastics is to improve processing performance, improve use efficiency and reduce costs. Additives account for a small proportion in plastic materials, but they have a great influence on the quality of plastic products. Different kinds of plastics need different kinds and dosage of additives because of different molding methods and using conditions. The main auxiliary equipment is as follows:

(1) plasticizer:

Plasticizers can increase the flexibility, ductility and plasticity of plastics, reduce the flowing temperature and hardness of plastics, and are beneficial to the molding of plastic products. Commonly used are phthalate, sebacate, chlorinated paraffin and camphor. The most common is camphor.

(2) stabilizer:

Mainly used to prevent thermal aging, known as heat stabilizer; Mainly used to prevent oxidative aging, called antioxidants; Mainly used to prevent photoaging, called light stabilizer, collectively referred to as stabilizer. At present, the best plastic stabilizer is methyl tin heat stabilizer (18 1), which is very effective for calendering, extrusion, injection molding and blow molding of rigid polyethylene (PVC).

Because of its high safety, it is especially suitable for food packaging and high-definition rigid polyethylene products. At the same time, it is also widely used in plastic doors and windows, water pipes and decorative materials to replace other highly toxic plastic heat stabilizers. It has been widely used in America, Europe and Japan. In recent years, 18 1 methyl tin heat stabilizer has been widely used in China.

(3) Flame retardant:

Additives that can improve the flame retardancy of plastics are called flame retardants. Most plastics containing flame retardants are self-extinguishing or slow in combustion. Commonly used flame retardants include antimony oxide, compounds of aluminum and boron, halides and phosphates, tetrachlorobenzene phthalic anhydride, tetraphthalic anhydride and so on.

(4) antistatic agent:

Antistatic agents can eliminate or reduce static electricity generated on the surface of plastic products. Antistatic agents are mostly electrolytes, which have limited compatibility with synthetic resins and can migrate to the plastic surface to absorb moisture and eliminate static electricity.

(5) foaming agent:

Plastic foaming agent is a kind of low molecular organic matter that can be gasified at a certain temperature, such as dichlorodifluoromethane; Or organic compounds that decompose gases when heated. These gases remain in the plastic matrix, forming foam with many fine foam structures. Azo compounds and nitroso compounds are usually used.

(6) Colorant:

Colorants are used to color plastics. Mainly plays the role of beautification and decoration. About 80% of plastic products are made into final products after coloring.

(7) Lubricant:

Lubricant is a substance added to improve the demoulding property of plastic during heating molding and improve the surface smoothness of products. Commonly used lubricants are: stearic acid and its salts, paraffin wax, synthetic wax, etc.

(8) Reinforcing materials and fillers:

In many plastics, reinforcing materials and fillers account for a considerable proportion, especially reinforcing plastics and calcium-plastic materials. Main uses: in order to improve the strength and rigidity of plastic products, various fiber materials or inorganic substances are generally added. The most commonly used reinforcing materials are: glass fiber, asbestos, polystyrene, carbon black, silicate, calcium carbonate, metal oxide and so on.

Extended data:

Development of plastic industry;

The development direction of plastics can be summarized into two aspects. On the one hand, it is to improve the performance, that is, to modify the existing varieties in various ways to improve their comprehensive performance; The other is the development function, that is, the development of polymer materials with optical, electrical, magnetic and other physical functions, so that plastics have photoelectric effect, thermoelectric effect and piezoelectric effect.

Judging from the current development speed of plastics industry in the world, Germany and Sweden rank first, followed by Japan and some European countries, and the United States is slower. Foreign plastic packaging presents the following development trends:

1, * * * poly composite packaging film:

At present, some countries in Europe and America have invested heavily in developing nonpolar and polar ethylene polymers, which will greatly improve the tensile and extrusion properties of plastic films, improve transparency, sealing strength, stress resistance and crack resistance, enhance stability and improve the rheological properties of molecular weight distribution and extrusion.

2. Multifunctional composite membrane:

A large number of multifunctional composite membranes have been developed abroad to further improve their functions. For example, the cold-resistant membrane can withstand the low temperature environment of-18℃, -20℃ and -35℃; The moisture-proof film made of PP can be divided into several types, such as moisture-proof, dew-proof, evaporation-proof and humidity-regulating. Anti-corrosion film can package perishable, acidic and sweet foods; Friction film accumulation is stable; Special PE film is resistant to chemical corrosion.

Adding odorless insect repellent into the moth-proof film; The biaxially oriented nylon 66 heat-resistant film was used instead of biaxially oriented nylon 6 to package food, and its high temperature resistance reached 65438 040℃. The new special food packaging film can improve the fragrance retention rate of food packaging; The transparency of amorphous nylon film is similar to that of glass; The high shielding film can keep the stability of color, fragrance, taste, nutritional index and taste quality; The metal protective film adopts LDPE modified film to package liquid products, which can be heat sealed at low temperature.

PP synthetic paper is used to improve the light resistance, cold resistance, heat resistance, water resistance, moisture resistance, oil resistance, acid resistance, alkali resistance and impact resistance of packaging. At present, plastic cups and composite cups (outer psP, inner PP and covered PS) are popular in foreign countries to package hot and cold drinks, wines and convenience foods. France uses PE bottles to package fructose and yogurt, while Germany uses PC bottles to package milk. In China, polyethylene bottles are used to package medicines.

Baidu encyclopedia-plastic products industry

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