It is said that these six additives are used in fi

2022-07-26
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It is said that these six additives are used in film processing. Some resins or film products have inherent properties that do not meet the requirements of the required processing technology, and additives need to be added to change their processability; Other materials have good processability, but the product performance can not meet the requirements. Additives should also be added to change the product performance

film requirements for additives

compatibility

poor compatibility will lead to "migration", which is manifested in "sweating" in liquid additives and "frost spraying" in solid additives

sometimes, when the requirements for the film are not too strict, it can be allowed to lack some compatibility, such as poor compatibility between the filler and the resin. As long as the particle size of the filler is small, it can still meet the basic requirements of the film performance. If it is treated with coupling agent or surfactant, it can better play its function. However, there are some additives to improve the surface properties of the film, such as opening agent, antistatic agent, etc., which require a little mobility to make it play a role on the surface of the film

durability

requires that additives exist in the film for a long time with little or no loss, and the loss of additives is mainly through three ways: volatilization, extraction and migration. This is mainly related to the molecular weight of the additive, the solubility of the recorded data in the medium and the solubility in the resin

processing conditions

the processing conditions of some resins are harsh. If the processing temperature is high, whether the selected additives will decompose and whether the additives have corrosive effect on the processing equipment should be considered

film application

films with different applications have different requirements for the odor, toxicity, weather resistance and thermal performance of additives. For example, plastic bags for food are required to be non-toxic, so the additives used are different from those used for general packaging

synergism and phase antagonism in the coordination of additives

in the same resin system, some two additives will produce "synergism". If the coordination is improper, some additives may have "mutual resistance", which will weaken the function of each additive or even make it ineffective. For example, the combination of carbon black and phenolic antioxidants will produce resistance

additives that can change film packaging performance

plasticizers and heat stabilizers

plasticizers and heat stabilizers can greatly improve the compatibility of film materials

plasticizer, as the name suggests, is a substance that increases the plasticity of the material. On the one hand, it increases the fluidity of the resin during molding, and neopentyl 2 alcohol is a good solvent to improve the processing performance. On the other hand, it can increase the flexibility and elasticity of the film

heat stabilizer is mainly used to improve the thermal stability of resin

light stabilizer

polymer materials will rapidly age under the irradiation of sunlight, light and high-energy rays, showing yellowing, embrittlement, cracking, surface loss of gloss, greatly reduced mechanical and electrical properties, and even lost their use value. In this complex destruction process, ultraviolet light is the main reason for the aging of polymer materials. It is mainly the result of the combined action of ultraviolet rays in sunlight and oxygen in the atmosphere on polymer macromolecules

role of light stabilizer:

it can effectively absorb ultraviolet rays with a wavelength of 290~410nm, eliminate or weaken ultraviolet rays, protect polymer material films from damage by ultraviolet rays and oxygen, prolong service life and improve light resistance of materials. Since most of the light stabilizers can absorb ultraviolet light, they are also called UV absorbers

addition amount of light stabilizer:

according to the action mechanism of light stabilizer, it can be divided into light shielding agent (pigment), ultraviolet absorber, ultraviolet quenching agent and free radical trapping agent. These four modes of action constitute four levels of light stabilization

after adding light stabilizer, although the dosage is very small, its anti-aging effect is very significant, generally only 0.1%~0.5% of the weight of polymer needs to be added

antioxidant

for most plastic varieties, they are sensitive to oxidative degradation in the process of manufacturing, processing, storage and application. Oxygen can penetrate into the plastic film and react with most polymers. This development is expected to be completed in 2020, resulting in degradation or cross-linking, thus changing the performance of the material. A small amount of oxygen can make the strength, appearance and properties of these polymer materials change dramatically. Under heat treatment and sunlight, the oxidation rate is faster. Therefore, the oxidation of polymers is usually divided into thermal oxidation and photooxidation. The final result of this reaction is performance aging. If this kind of reaction is not prevented, it can quickly oxidize the polymer and lose its use value

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