Plastic film products with additives and the type of industry applications

Plastic resin additives to improve the processing performance and adding properties and use of chemicals. Often used in the plastics additives have more than 10 categories, with the number of varieties of plastics, and expanded use of the processing technology advances in the type and variety of additives are also on the rise.

In the plastic film processing and use of the process to join the plastic additives. Is because some of the resin film or the inherent properties of the product not meet its requirements for the processing of requests to add auxiliary just need to change the nature of its processing; materials and some of its better performance processing, product performance and not be able to meet our Request, which also aids add to change the properties of their products. Of course, these two roles are complementary to each other, sometimes at the same time in order to achieve the objective of the two.

First introduced here can change the use of plastic packaging film performance of the additive.

Auxiliaries to the general requirements

Compatibility

In general, the only agent with the resin between good compatibility, can the agent long-term, stable, evenly present in the film, to be effective. If compatibility is not good, is prone to "move". In the performance of the liquid agent on a "sweating", in the solid performance of the additives in the "spray frost". However, in some cases less stringent requirements on the film, still allows its lack of compatibility, such as filler between the resin and compatibility is not good, but as long as the filling of small size, and still be able to meet the basic requirements of performance films, of course, If the coupling agent or surfactant to deal with you, you better perform their functions. However, there are a number of films to improve the surface properties of additives such as the opening agents, anti-static agent is required to move a little, some, to make the film on the surface of the work.

Durability

Is a long-term durability requirements of additives present in the film but not essential or very little damage, and loss aids, primarily through three channels: volatile, and move out. This is the main agent with the molecular weight of large and small, medium and solubility of resin in the solubility-related.

Adaptive processing conditions

Some of the resin processing than the harsh conditions, such as high-temperature processing, at this time should be given to the selected agent will break down any auxiliary equipment for processing corrosive effect.

Films on the use of the additive constraints

The use of different additives on the film of the smell, toxicity, weather resistance, thermal properties, and so have certain requirements. For example, loading plastic bags of food, as a result of drug-free requirements, it is used by the agent and general packaging of plastic additives used are different.

Auxiliary co-ordination between the proposition and the synergy effect

At the same resin system, and some will have two auxiliaries "synergy", that is, than all alone with a particular Additives, to play a large multi-functional. However, if the proper co-ordination, and some additives that may arise between the "proposition" that it would weaken the function of each agent, or even a loss of auxiliary role that special attention should be paid, such as carbon black and amine or phenol Antioxidant category and will have a role in combat. Plastic packaging films used performance additives

Plasticizers and heat stabilizers

Plasticizers, as its name implies is to increase the plastic material, that is added to the resin, on the one hand, so that when the resin molding in increased mobility and improve the processing performance, on the other hand, can make the film after the flexibility and increase the flexibility of the material .

Heat stabilizer is to improve the thermal stability of the resin for the purpose of adding additives. For polyvinyl chloride and vinyl chloride copolymer processing.

Light Stabilizer

Polymer materials in the sun, and high-energy rays of light exposure, the rapidly aging occurs, for the performance of the yellow, become brittle and crack the surface dull, mechanical properties and electrical properties are greatly reduced or even lost the final value. In this complex process of destruction, UV polymer is the main reason for starting role in aging. Mainly in the ultraviolet sunlight and atmospheric oxygen to the combined effects of macromolecular polymers.

In order to protect the polymer film from oxygen and ultraviolet radiation damage, they extend the useful life of the light stabilizer will be added to plastic materials to make them in resin absorption of ultraviolet energy and the energy absorbed by the sound Out in the form of conversion. In order to inhibit or weaken the role of the degradation of light and improve light resistance materials. As the majority of the light stabilizer will be able to absorb ultra-violet light, it is also known as ultra-violet light stabilizer for the absorbent. Evaluation of a UV absorber of good or bad, it is necessary to take into account the performance, processing, pricing, non-toxic, and so on, can not separate the two stressed the effect of a particular. Taken together these conditions are as follows:

n effective absorption wavelength of 290 ~ 410nm UV, and absorption bandwidth; be able to effectively eliminate or reduce UV damage to the polymer, while the other polymer did not affect the physical and chemical properties;

n itself has a good stability, long-term UV exposure, the absorptive capacity will not decline;

n good thermal stability, processing and use of shape when the process does not become invalid because of the heat, do not change color; polymer does not affect the processing performance;

n compatibility with the polymer, in the course of processing and use of non-separation, migration, water and can not easily be solvent extraction, evaporation is not easy;

N non-toxic or low toxicity;

n chemical stability, and not the other components of materials in chemical reactions and damage to the properties of materials;

n to the low absorption of visible light, non-staining, does not change color;

n cheap, easily manufactured, a rich source.

Light Stabilizer in accordance with the mechanism, can be divided into four categories: ①-ray shielding agent (paint); ② UV absorber; ③ ultraviolet quenching agent; ④ radical capture agents. The role of these four ways constitutes a light in a gradual stabilization in-depth four levels, each able to suppress levels of UV polymer body damage, in line with the specific design, or a level of protection at every level Should be as thin films and use of environmental requirements. Light Stabilizer to join, even though very little amount, which prevent the effects of aging is very significant, generally only the weight of the polymer by adding 0.1 percent to 0.5 percent.

Used a lot of light stabilizer, in accordance with their different chemical composition and mechanism, including: ①-o-diphenyl ketone (such as UV-9, UV-531 and so on); ② benzotriazole category (such as UV -P, UV-327, UV-326, etc.), ② acid esters (BAD, TBS and so on); ④ triazine; ⑤ ⑥ replace acrylonitrile-type organic nickel complex; ⑦ hindered amines. These types of absorbent performance to benzotriazole category and triazine for the best.

Antioxidant

For most of the plastic variety, in its manufacturing, processing, storage and application process, the oxidation of a certain degradation of the sensitivity of the infiltration of oxygen in the thin film of plastic polymers can be almost the majority of the reaction leading to degradation or cross - Together, so as to change the properties of materials. A small amount of oxygen so that they can be the strength of polymer materials, the look and performance of dramatic changes. In the hot sunshine and processing, faster oxidation. As a result, the polymer will generally be divided into oxidation and thermal oxidation photo-oxidation. Finally, this reaction is the result of the aging properties. If this type of reaction is not to stop, you can quickly make the polymer oxidation and loss of use value. Different oxygen on the stability of the plastic is different, so there is no need to join in plastic antioxidant. Some of you must join the antioxidant, is to capture the role of the antioxidant activity of free radicals, so that the interruption of a chain reaction with the aim of delaying the process of oxidation of plastics and speed. According to the antioxidant mechanism, which all plastics are effective.

Antioxidant chemical structure can be divided into: 1. Polyphenols, including: single-phenol, bisphenol, three-, polyphenols, hydroquinone, the bisphenol thio; 2. Amines, including: naphthylamine, the Second Aniline, p-phenylenediamine, quinoline derivatives, as well as lipid phosphorous, sulfur and other kinds of esters.

In the above categories, phenols, amines is the main antioxidant, accounting for about 90% of the total amount, general, the protection of the amine antioxidant polyphenols than high-performance, but by Amine Light, the role of oxygen, occurs in varying degrees of color, does not apply to light-colored, Chromic and transparent film, so the application of plastic film less.

In accordance with the antioxidant effect of antioxidants will be the main points and supporting antioxidant antioxidant. Aniline better antioxidant effect, but more polluting, mainly for rubber; phenolic antioxidant effect less, but less pollution, better integrated, multi-use plastic film. Usually, or S-mercaptan, was placed under the auxiliary phosphite antioxidant, with the main antioxidant and to have a synergistic effect, to extend the effectiveness of antioxidant.

At present, the antioxidant production and research towards high-performance, low toxicity, low-cost way. As a result, phenolic antioxidants will gradually than antioxidant amines. Alkyl used to replace some of the phenyl, you can make the type of antioxidant and polyolefin plastic to improve compatibility. Antioxidants increase the molecular weight is to improve the durability of antioxidant important way. Most of antioxidant easy to move, protection so that the loss of polymer, the molecular weight antioxidant large enough to reduce the possibility of migration can be an effective antioxidant to increase life expectancy.

Lubricant

After the polymer melt in the usually has a high viscosity, in the process, the polymer melt through the narrow, the flow gate, and so on, the polymer melt processing machinery and must have a surface friction Some friction in the processing of polymer is very negative, the melt flow so that the friction-reducing, at the same time a serious film on the surface friction will become rough, the lack of sheen or rhyolite. To this end, adding to the need to improve lubricity, reduce friction and reduce the adhesion properties of the interface for the purpose of the additive. This is the lubricant. In addition to improving the mobility of lubricant, but also can promote the melting agent, anti-adhesion and anti-static agent, the agent Shuanghua role.

Lubricants can be divided into inner and outer lubricant two lubricants, lubricants outside the main role is to improve the polymer melt processing equipment and the heat of friction on metal surfaces. Its compatibility with the polymer less easy to melt from the inside out migration, they are able to melt the plastic and metal interface to form thin layer of lubrication. Polymer and lubricant with good compatibility, it has played in the polymer to reduce internal cohesion between the polymer molecule, so as to improve the plastic melt in the heat of friction and melt mobility. Commonly used outside the lubricant is stearic acid and its salts; lubricant inside is low-molecular-weight polymer. Lubricants and some other function. Each has a real lubricant can request a particular role, both within and outside the lubrication always together, but in a sense some of the more prominent. The same type of lubricant on different polymers or different processing conditions will show a different lubricant, such as high temperature and high pressure, with lubricant will be squeezed out of the system as a lubricant outside.

In the plastic film production, we also encountered a number of adhesion phenomena, such as in the production of plastic film, film is not easy to separate two-story, which automatically to the high-speed packaging difficult. In order to overcome it, add a small amount of resin to increase the surface lubricity additive, to increase the external lubrication, generally known as anti-adhesion agent or agents Shuanghua. General molecular structure of the lubricant, there will be a long chain of non-polar and polar two parts, they are different in polymer compatibility is not the same, as evidenced by the different internal and external lubrication. In accordance with the chemical component, commonly used lubricants can be divided into the following categories: fatty acids and esters, fatty acid amide, metal soap, hydrocarbons, organic compounds such as silicon.

Lubricants in the actual processing of plastic with a variety of performance, such as mixing, rolling process, to prevent the adhesion of polymer bowl, suppression of friction heat, reduce the mixer and the torque load so as to prevent the polymer material Thermal degradation. In extrusion, to improve liquidity and improve polymer materials and bowl with the adhesion of the mold, to prevent and reduce the residual material. Another film can improve the appearance and sheen.

Processing machinery from the point of view, the mixing, rolling, forming, such as Tang Su, outside the lubricants plays an important role in the extrusion and injection molding, with lubricant is more effective.

In general the amount of lubricant 0.5 percent to 1 percent, to be selected:

n the flow properties of polymers have to meet the needs of the molding process, the main consideration, the role of lubrication in order to ensure internal and external balance;

n outside the effectiveness of lubrication, it should be based on the possibility of forming when the temperature in the plastic surface to form a complete film of liquid which, therefore, outside the melting point of the lubricant should be close to forming temperature, but a difference of 10 ℃ ~ 30 ℃ side Be able to complete the formation of the film;

n does not reduce the polymer's mechanical strength, as well as other physical properties.

In the production of lubricants to choose when to meet the following requirements:

N-lubricating high performance and long-lasting;

n compatibility with the resin size, internal and external balance of lubrication; not spray frost, the scale is not easy;

n gravity on the surface of small, small viscosity, in the interface of scalability, easy-interface layer;

n as much as possible without lowering the excellent performance of polymer, plastic does not affect the performance of secondary processing;

n their heat resistance and good chemical stability in the processing of non-biodegradable, non-volatile;

n non-corrosive, non-pollution films, there is no toxicity.

However, simply using a lubricant, it is often difficult to achieve their goals and will take several joint lubricant, lubricating composite developed rapidly in recent years, the choice can be viewed from different angles and lubricants.

There are commonly used lubricants stearic acid, butyl stearate, oil-, ethylene bistearic amide, and so on.

A lot of paraffin-type material can be used as a lubricant, such as natural paraffin and liquid paraffin (white), microcrystalline wax and so on, but the effects are mixed. Natural paraffin and more to do with external lubrication, a variety of plastics can be used as lubricant, release agent, in general the amount of 0.2 ~ 1phr, but their compatibility, thermal stability and the dispersion is not good, not the amount is too large, with the best Within and lubricants; white oil and more to do with PVC, PS within the lubricant, lubricating properties, thermal stability is also very good, in general usage 0.5phr. They are drug-free, can be used for food packaging. Another kind of microcrystalline wax: China Plastics Processing It has also been used as a lubricant, the amount of 1 ~ 2Phr, thermal stability and lubricity better than ordinary wax.

Low-molecular-weight polymer is also widely used as a lubricant, such as polyethylene wax, low-molecular-weight polyacrylamide, and its internal and external have good lubricity, and non-toxic. Polyethylene wax applied to materials such as PVC extrusion, rolling processing, usage is generally 0.1 ~ 1phr, improve processing efficiency, to prevent the film adhesion to improve the dispersion of pigments or fillers, compatibility and transparency is not very good; non-regular Low-molecular-weight polyacrylamide structure can be used as rigid PVC, PE lubricant, good performance, can improve the dispersion of other additives, in the amount of 0.05 ~ 0.5phr.

Anti-fog agent

Transparent plastic film, sheet or plate, in the humid environment, when the dew point and humidity to achieve the following, in its condensation on the surface layer of tiny water droplets, so that the surface of fuzzy atomization, hampered by the waves, such as the use of film packaging products , Would end because of fog and the contents can not see, and the resulting droplet also easily lead to damage to the contents of decay.

Anti-fog agent is to prevent the above-mentioned fogging phenomenon and the use of a class of agent. They are some of the water with a surface-active agent, can be oriented in the plastic surface, inward-hydrophobic, hydrophilic-out, so that the easy-to-wet plastic surface water, small droplets of condensation to form the rapid spread very thin water Shun-or water flow down the film. This would avoid the small drops of light scattering caused by fogging, to prevent condensation of water droplets Sala to be above packaging, packaging has been damaged.

In accordance with anti-fog agent in the way of accession to the plastic can be divided into anti-fog agent in Canada and two categories-treated. Anti-added ingredients when the agent is added to the resin, which is characterized by loss of hard, durable performance, but with a high degree of polymer crystallization difficult to obtain a good anti-;-treated anti-fog agent is soluble in In the water or organic solvents, plastic film applied to the surface, and the use of simple, low cost, but poor durability, easily washed away or erased, only Canada, anti-agent invalid or occasions when it does not require persistent use.

The effectiveness of anti-fog agent can be divided into the early fog, durable fog, low temperature and high temperature anti-fog and anti-fog four, a fog of four very difficult for both effects, often on the film is based on the anti-fog The effect of the requirements, with the use of several choices.

Fog of chemical agents mainly composed of fatty acids and some of the polyol-esterification. Polyols are used glycerol, sorbitol and its anhydride, used the fatty acid is C11, C12 of saturated fatty acid, or acid, carbon atoms for more than 24 fatty acids can also be used. In general, medium-chain fatty acid ester of the early effects of a good anti-fog; long-chain fatty acids in the fat fog lasting good effects. In fact a variety of anti-fog agent is often mixed acid ester, a number of polyol fatty acid ester of a lack of water, through the addition of ethylene oxide, may increase the water, increasing the initial anti-fog and low temperature.

Anti-fog agent should have the following properties:

1. Antifog high-performance, the rapid entry into force, good durability;

2. Thermal stability, and resistant to heat decomposition and decomposition does not lead to degradation of the polymer;

3. And other additives with the good, without prejudice to other auxiliary functions;

4. Does not affect the transparency of the film, electrical properties, adhesion, resistant to pollution, such as sexual function.

Here are some typical anti-fog agent.

Single-oil glycerol ester of a white waxy material can be added as an anti-agent, has a good initial anti-fog and low temperature for food packaging films, in general the amount of polyethylene in 1 ~ Were 1.5, 0.5 for polyolefin 1. Sorbitol anhydride palmitate single yellow granular material, in order to increase anti-agent, the rapid entry into force of the durable, vinyl chloride in the amount of 1 to 1.7 copies.

Sorbitol anhydride monostearate also added anti-agent, yellow granular solid, the melting point of about 60 ℃, lasting performance, commonly used in agricultural films, can also be used for food packaging materials, which in PVC The amount is generally 1.5 to 1.8 were in the polyvinyl acetate in the 0.7 to 1.

PEO (20) monostearates also added anti-agent, the entry into force very quickly, has good anti-fog and low temperature and early. It is a pale yellow liquid, at the same time, anti-static performance for food packaging films. In general the amount of PVC in the 1.5 to 1 which, in polyolefins for 0.5 ~ l 000.