Usual additives used depends on production, processing and end-use requirements of plastic products, corresponding, additives and processing aids can be divided into functional additives. Where plastic additives in the production process, the resin can protect against heat, oxygen, shear and other factors in the destruction or improve resin processability collectively referred to as processing aids, such as antioxidants, heat stabilizers, lubricants and the like. Plastic can impart a particular function or use of adjuvants is called functional additives, such as antistatic agents, anti-aging agent, flame retardants, slip agents, and antibacterial agents.

 

Plastics additives polymer resin due to the choice of different structures exhibit different processing characteristics, thus can be divided into thermoplastic and thermosetting resins, crystalline and non-crystalline polymer. Different resins different processing methods, the final product because the same type of resin use of different molding processing in different ways, such as: blow molding, injection molding, slush molding, rotational molding, casting, rolling, extrusion and the like. Grade plastics industry because of their different applications for different functional requirements, required functional additives are also different.

Depending on the selection process and functional additives, often a target corresponding to an adjuvant. Multi-performance plastics need more aid, but a variety of additives are mixed together, the performance does not necessarily play a synergistic anti synergies sometimes exist, but rather a deterioration of physical and mechanical properties of products, and therefore aid should be chosen carefully .

Selection of additives, generally should follow the following principles:

(1) in a given formulation and processing system, and give full play to their own effectiveness;

(2) without deterioration or minimally affect the basic physical-mechanical properties of the resin;

(3) does not deteriorate minimally affect the play or the efficacy of other additives, and other additives have better synergy;

(4) processing thermal stability of plastic products mostly thermoformed, should ensure that aid small loss in the process, not bad, do not break down (except the blowing agent), volatile products processing equipment, operators and environmentally sound that the aid should be passed off process. The same type of functional additives or processing aids There are many varieties, not every breed is suitable for various kinds of plastic or plastic and some additives does not match the thermal behavior of the base resin. This does not match the thermal behavior could easily lead to failure of plastic processing. Some, such as engineering plastics processing selected GE Plastics processing aid, and finally in the extruder aid due to decomposition foaming difficult to mold, functioning out of the question; lower thermal stability of antistatic agent for B0PP film production, produce large amounts of pungent blue smoke die, endangering the operating environment, product quality and performance.

Some aid their high thermal stability, it is possible to limit its function. As the blowing agent decomposition temperature is higher than the foaming temperature, flame retardants, when the substrate thermal decomposition and still not produce capture free radicals, blocking the activity of free radicals and other active substances or combustion chain reaction.

Compatibility with the base resin selected additives in addition to considering the effect of the mandatory, but also must start from the similarity of the base resin and additives and structure differences, judging both compatibility. Aid good compatibility with the base resin, will not deteriorate (possible increase) physical-mechanical properties of the substrate, and also improve the migration resistance, resistance to extraction. Analyzing both compatibility based on multiple follow similar principles of compatibility, similar structure, similar polarity, similar molecular weight, etc. are conducive to improve compatibility. For compatibility with the base resin is poor, it is difficult to improve the amount of additives, must try to enhance or improve the compatibility, such as the use of a coupling agent or a compatibilizing agent that the surface chemical matter. Plastics modification research work has published two monographs, papers related to the number of functional additives support, various functional additives carp compound resin had to give up the choice. Modern Plastics Processing and Applications activation treatment, or microencapsulation process Wait.

Structure similar to the structure of the synthetic resin in a limited number of additives and structural complexity, not every polymer additives should choose to pick their close structural varieties, but the structure of the base resin additives similar to really improve the effectiveness of aid and overall performance of the article. For example, antioxidants having amide structure 1098 for nylon, the stabilizing effect is far superior antioxidant 1010, extraction resistance is also significantly better than the latter, and antioxidants for polyolefins or polyesters 1098, there was no any Advantage.

Differences similar polarity polarity direct impact on aid compatibility with the base resin. Polar additive resin matrix do not match, resulting in poor compatibility, physical-mechanical performance of product degradation, precipitation aids, surface bloom on the efficacy of additives shortened durability, color products, affecting the product rework Wait. Accordingly, non-polar or weakly polar polymers nonpolar additives should be selected, and polar polymer polar additives should be selected. For example, a cationic antistatic agents for PVC, the effect is significant; and for PE or PP, is achieving the desired effect. In another example, the production of agricultural PVC films add flow drops of up to 3% to 4%; production of EVA films, drops flow amount of 1.5% to 2.5%; and the production of PE films, only adding 1.2 flow drops % to 1.8%, otherwise the surface of the films soon to produce a white precipitate.

Relative molecular mass similar to high molecular weight polymer additives with low molecular weight in many ways difficult to synchronize dispersion behavior, melting behavior, crystallization behavior, directly affect the aid in polymer dispersion, migration and resistance to draw mention sex, but also directly affect the play aid functions. Aid of high molecular weight is to reduce this gap, one of the effective measures to improve compatibility. High molecular weight polymeric additives have type 2 and macromolecular species, such as antioxidant molecules 1010 than the low molecular weight antioxidant capacity of 1076 hydrolysis, resistance to extraction, and resin compatibility, persistent antioxidant function were significantly improved. Polymeric hindered amine light stabilizer 944,622,3346, HA88, N30 and other polyolefin compatibility are better than low molecular weight single molecule light stabilizer 770, GW540, etc., are also significantly reduced toxicity.

Improve the compatibility with the resin to improve the compatibility of the additive, it is sometimes necessary to use other measures such as the use of various types of coupling activation fillers, agents to improve the compatibility of different structures using resin compatibility, adjustment processes allow the the compatibility of the components.

Matching between the plastics additives industry in-depth application to one of the reasons is that it is multifunctional. Multi-functional plastic products is by blending more varieties, eutectic molding required between the various additives do not have a reactive, an adjuvant migration should not result in the loss of other additives, and performance can be complementary.

Chemical reaction leading to the loss of the matching system of anti-aging agent, a hindered amine light stabilizer class good, better than other types of light stabilizers, flame retardants but acidic occasion, generally not hindered amine, and use an ultraviolet absorber. Because flame retardants and acidic alkaline hindered amine light stabilizer occurs salinization reaction, leading to hindered amine failure. Similarly, there are also acrylic exterior paint problems in an acidic environment, and in this case, can be low-alkali HALS, it does not react with acidic substances, and thus play its excellent anti-aging properties.

Migration lead to the loss due to the need composite packaging film, the adhesive and the matching slip agent is critical, composite manufacturers often unjustified slip agent and the optional binder, adhesive strength attenuation cause severe performance degradation apparent slip problem. Because the adhesive agents are induced to slip, slip agent to migrate to accelerate complex interface. Beijing Research Institute of Chemical additives and adhesives through the study of the relationship between the developed polyurethane adhesive and amide slippery agent has a better coordination of.

Performance plastics complementary features should not be the simple sum of the efficacy of various types of aid, but should be the efficacy of various additives synergistically. Single auxiliary species, sometimes not a single function. Some antioxidants (1076,168, etc.) both light stability; heated some light stabilizers (such as 944), and oxidative stability as much as some of the hindered phenolic antioxidant species (such as 1010) flame retardant synergist with smoke suppression; there are flame-retardant fillers and the like. Some varieties with the use of a synergistic effect can be achieved. Therefore, the establishment of plastic products production formula, should be considered complementary to aid performance, in order to improve product performance and low cost.

Environmental compatibility. With low toxicity itself non-toxic plastic applications continue to broaden, particularly in-depth applications in the food, pharmaceutical industry, a lot of self-toxic additives to be eliminated or restricted, accidents (combustion) occurring in the application process will produce toxic substances additives (such as flame retardants) have also been restricted or disabled, non-toxic additive is one of development.

Reduce environmental harm in plastics processing, additives generate dust or heat toxic volatile compounds etc. would endanger the operator and operating environment. Waste plastics recyclability and environmental consumptive sex selection should also be a factor that must be considered aid. For example, a light stabilizer GW-540 has excellent optical, thermal stability, but the environmental hazard (sensitization) so that users do not play the efficacy of Plastic Additives 2 plastics processing and multi-functionality by adding all kinds of get aid, but this does not mean that as long as the proper selection of additives added to plastics can give full play to their effectiveness, aid effectiveness factors play very complicated.

The variety and amount of aid to people understanding the amount of additives is more often the better the performance (without taking into account the cost of the premise) In fact, for some aid, the amount of increase is not much, but then the performance of other products cause significant degradation.

Lower molecular weight antistatic agents which migrate faster, can play the effect in a short time, but in the use of the polyolefin resin, there is a holding effect poor shortcomings, and its application to engineering thermoplastics article It is not only a good antistatic effect, and persistent action to meet product demand.

Slip dosage slightly increased precipitation will make PE film surface was significantly increased, leading to composite bonding strength decreased faster.

Processing conditions processing conditions matching of different plastics, which restricts the use of some of the aid must be selected to match the processing aids, to pass off process.

      For the polyolefin materials (PE, PP), often require an antistatic agent has excellent heat resistance, high safety and health, as well as no adverse effect on the performance itself and other products. The use of ionic can not meet the above requirements, non-ionic antistatic agent is able to meet these requirements, a polyolefin-based material is the most commonly used species antistatic agent.

Polyvinyl chloride (PVC), polyurethane (PU) material of lower processing temperatures, and require anti-static situation often have no health requirements, while requiring high antistatic performance, this time should be used cation-containing antistatic agent.

Cationic antistatic agent antistatic effect is remarkable, but poor thermal stability, limiting their use.

Effect sizes products product sizes on aid performance play mainly in its thickness effect. On anti-aging products, the products are usually thin hindered amine light stabilizer, which is due to play its thickness is not related to performance and products, and no adverse effect on the properties of the products. The presence of the UV absorber thickness effect, the thinner the thickness, the worse the effect, less use of film products. In the injection molded article, and while the use of a hindered amine ultraviolet absorber, can synergistically. Common UV absorbers such as UV 326, etc., and hindered amine light stabilizers 770,622 and 944 with the use of light can effectively improve the performance and stability.

Additives for antistatic function, the injection-molded articles often than film products add more antistatic agents. This is mainly due to the thick injection molded products, antistatic agents migrate to the surface of the performance of the play long time, relatively low effective concentration.

Use of the environment on the performance of some of the features of the aid effectiveness play influenced by the environment, you should choose the right amount of the right species and according to the environment. The organic nonionic antistatic agent on the outside has a certain sensitivity to moisture, which with its related antistatic mechanism. Seasonal and geographical humidity is different in kind and amount of the antistatic agent must be adjusted accordingly, in order to meet the needs of the antistatic products from both performance and price.

Conclusion: General plastics engineering, high performance engineering plastics is inseparable from the implementation of aid Plastics Processing Industry ABC (alloys, composites, modified) target strategy, ABC strategy. Select and play the efficacy of aid aid is a complicated systematic project, we must fully consider the type of plastic, use, processing, use of the environment, a variety of factors such as synergistic additives. The correct selection of additives, in order to give full play to the effectiveness of aid, access to comprehensive high performance plastic products.