Modified Plastic Additives

During the processing of plastics, different types of additives often need to be added to meet the different processing and application needs of the material. Today we will briefly introduce these additives.

Plastic additives refer to various auxiliary materials added before or during plastic molding to facilitate product production and performance improvement.

According to the functional differences of additives in improving plastics, from the perspective of increasing the processing characteristics of the base material, additives include:

①Fluidity: Lubricant

②Thermal stability: heat stabilizer, antioxidant

③Dispersion: processing aids, dispersants

④Compatibility: compatibilizer, coupling agent

⑤Melt strength: bridging agent, tackifier

From the perspective of increasing the physical and chemical properties of the substrate, additives include:

① Rigidity and strength: filler, crystal nucleation agent

②Impact: impact modifier

③Heat resistance: filler, nucleating agent

④Flame retardant: flame retardant

⑤Weather resistance: stabilizer, UV stabilizer

⑥Conductivity: antistatic agent conductive filler

⑦Color: Toner

⑧Softness and hardness: plasticity processing oil

⑨Density: Foaming agent

⑩Transparency: crystal nucleating agent

⑪Hygiene: antibacterial agent

Instructions for use of various additives:

Functional masterbatch: More functional additives are needed in the manufacturing and molding of plastics. Choosing appropriate carriers and functional additives to prepare masterbatch can facilitate downstream manufacturers' preparation and avoid problems such as mixing, dispersion, feeding and unsatisfactory effects.

Processing aids: Processing aids refer to additives used to improve the rheology and molding properties of plastic processing. They are usually additives with low viscosity or surface energy and a certain lubrication effect. Including plasticizers, lubricants, dispersants, release agents, etc.

Stabilizing additives: Stabilizing additives include antioxidant additives, light stabilizing additives, acid neutralizing additives, etc. It is mainly used to prevent oxidative degradation of polymers during transportation, processing, molding and use, and to maintain the performance and appearance of the material.

Antistatic agent: Polymers can easily generate static electricity through friction, which can easily cause dangerous radicals or even fires. Therefore, it is necessary to eliminate the static electricity on plastic products. Antistatic agents can reduce the accumulation of static electricity during the processing and use of plastics and reduce the surface resistivity of the material.

Silane coupling agent: In the polymerization of polyene, both the electron donor and the main catalyst play a crucial role. The tacticity of the product can be manipulated through the selection of electron donors, thereby modulating the properties and applications of the final polypropylene product.

Flame retardant: Flame retardants are chemical additives that can improve the burning properties of combustible materials. They are polymer materials modified by flame retardants. When attacked by a fire source, it can effectively prevent, delay or terminate the spread of flames, thereby achieving a flame retardant effect.

Nucleating agent/transparent agent: Crystallization accelerator, also called nucleating agent, is suitable for semi-crystalline plastics. It is a new functional additive that shortens the molding cycle and improves the optical properties and physical and mechanical properties of products by changing the crystallization behavior of plastics.

Basic requirements for selecting additives and application considerations:

1. The additives should have good compatibility with plastics so that they can exist in the product stably and uniformly for a long time and exert their effectiveness. If the compatibility is not good, the additives will easily precipitate.

2. The additive should be durable. Choose additives that are not easy to volatilize and migrate from the plastic.

3. The additives must have good adaptability to the processing conditions. The most important thing is that the additives are required to be difficult to decompose, volatilize and sublime at processing temperatures.

4. Additives should not be polluting or toxic to the product. Additives should not have harmful effects on personnel engaged in processing and application. When used as food packaging and toys, compliance with hygienic standards should be absolutely guaranteed.

Precautions for application of additives

(1) Matching of additives and polymers: The additives should match the polymer. This is the first issue to consider when selecting additives. Compatibility of additives and polymers, including their compatibility and interaction in terms of stability.

(2) Durability of additives: This is also an issue that must be considered when selecting additives. The loss of additives mainly occurs through three pathways: volatilization, extraction and migration.

(3) Adaptability of additives to processing conditions: The processing conditions of some polymers are relatively harsh, such as high processing temperatures and long processing times. Therefore, it is necessary to consider whether the additives can adapt. The same polymer may require different additives due to different processing and molding methods. The most important requirement for additives under processing conditions is heat resistance, which means that the additives must not decompose, volatilize, or sublime at the processing temperature. In addition, attention must be paid to the possible corrosive effects of additives on processing equipment and molds.

(4) Restrictions on additives due to product use: The selection of additives is often restricted by the final use of the product, which is an important basis for selecting additives. Products with different uses have certain requirements on the appearance, odor, pollution, durability, electrical properties, thermal properties, weather resistance, toxicity, etc. of the additives used.

Synergy and opposition in the combination of additives: A polymer often uses multiple additives at the same time. These additives are in ten polymer systems and have an influence on each other. If matched properly, different additives will often synergize with each other, that is, they will achieve the desired "synergistic effect". One of the main purposes of polymer formulation research is to discover synergistic effects between additives.

(5) Several common additives in the plastic modification industry:

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