Plastic additives
DATE：2022/7/1 8:42:57 / READ： / SOURCE：This station
Plastic additives
Additives are also called additives. The purpose of adding additives is to improve the processability and serviceability of plastic products, or reduce the cost of plastics. There are many kinds of additives for plastics (including foamed plastics), which are introduced according to their classification and functions. Lithium battery diaphragm production line www.handern comFoaming agent is a kind of substance that makes the plastic in viscous flow state form honeycomb cell structure. It can be solid, liquid, gas or a mixture of several substances. When the external conditions change, such as temperature rise and pressure reduction, the blowing agent generates gas through physical or chemical changes, filling the polymer melt with gas, and finally forming foam. Foaming agent is divided into physical foaming agent and chemical foaming agent. Lithium battery diaphragm production line www.handern com
The physical foaming agent generates bubbles in the foaming process by the change of its physical state, such as the bubbles generated by the vaporization of volatile liquid. It is generally divided into inert gas and low boiling point liquid. Lithium battery diaphragm production line www.handern com
The requirements for physical foaming agent are as follows. ① It is non-toxic, non corrosive, non combustible, and has a certain stability to heat and chemicals. ② it does not affect the physical and chemical properties of the polymer itself. The penetration rate through the polymer membrane wall shall be less than that of air. ③ At room temperature, the steam pressure is low and it is liquid for storage, transportation and operation. ④ The chemical foaming agent has a wide range of sources and is cheap. The chemical foaming agent changes under the action of heat and decomposes into gases. Generally, it is divided into organic foaming agent and inorganic foaming agent. Inorganic foaming agents mainly include sodium bicarbonate, ammonium carbonate, etc., and organic foaming agents are the main foaming agents for the chemical foaming method of foamed plastics at present.
The requirements for chemical blowing agent are as follows. ① Foaming agent has good dispersibility in plastics. The heat release during the decomposition of foaming agent shall not be too large. The gas evolution is large and rapid, and the temperature of the gas released from decomposition should be stable. ② the gas released from the decomposition of foaming agent and the residue left should be non-toxic, tasteless, non corrosive, colorless, and have no adverse effect on polymers and other additives. ③ The outgassing speed of foaming agent should be controlled and adjusted by changing the molding conditions. ④ The foaming agent has stable chemical properties, is convenient for storage and transportation, and will not decompose during storage. ⑤ It is cheap and comes from a wide range of sources. Lithium battery diaphragm production line www.handern com
The plasticizing principle is that the plasticizer molecules are inserted between the polymer molecular chains, which weakens the attraction between the polymer molecules, increases the activity of the polymer molecular chains, reduces the crystallinity of the polymer, thus increasing the plasticity, flexibility and cold resistance of the polymer, reduces the glass transition temperature, softening temperature or viscous flow temperature of the plastic, reduces the viscosity, increases the fluidity, and greatly improves the formability of the plastic. Lithium battery diaphragm production line www.handern com
Plasticizers are generally high boiling point liquids or low relative molecular weight (low melting point) solids. The variety is complex and there are many classification methods. According to the use and performance of the product, it can be divided into cold resistant, heat-resistant, non-toxic, electrical insulation and other plasticizers; According to the molecular structure, it can be divided into monomeric and polymeric plasticizers; It can be divided into main plasticizer, auxiliary plasticizer and increaser according to the use conditions (mainly judged according to the compatibility of resin and plasticizer). Lithium battery diaphragm production line www.handern com
Classification by chemical structure is the most common classification method, which is generally divided into the following categories. ① Phthalate esters are the most commonly used main plasticizers with good compatibility and soft and comprehensive performance. Such as dioctyl phthalate (DOP), dibutyl phthalate (DBP), etc Isoproterozoic dibasic acid enzymes are especially good at low temperature and good stability, which is sweet and cold auxiliary 0). When used together with the main plasticizer, it can improve the cold resistance. For example, dioctyl sebacate (DOS) and dioctyl azelaic acid (doz) have good low-grade softness and smoothness of fatty acids, but poor mobility, oiliness and heat resistance. For example, Trimethylphenol phosphate (TCP) and triphenyl linoate (top), etc. ④ Epoxy esters are auxiliary plasticizers. Excessive dosage will cause overflow. They are generally mixed with DOP. Epoxy ester plasticizers have the characteristics of good heat and low temperature resistance. Such as epoxy soybean oil (ESO), epoxy octyl stearate (ED), etc. ⑤ , good performance and other advantages can also reduce the cost of plastic, but due to poor compatibility, the dosage should not be too large, such as oxidized paraffin (chlorine content 42%~52%). There are many kinds of plasticizers, and the following conditions should be met when selecting them. ① The selected plasticizer has good compatibility with the resin used. ② The plasticizing efficiency is high, that is, after adding a certain amount of plasticizer, its performance changes obviously. ③ It has good durability, low volatility, low mobility and high extraction resistance.
④ Good chemical stability, light resistance, heat resistance, bacteria resistance and chemical resistance. It is hygienic, non-toxic, tasteless and non polluting.
⑤ Low price. Lithium battery diaphragm production line www.handern com
Author：admin