Plastics

Polymer additives – why do we use them?

The industry uses many types of polymer additives that can be divided into four main groups:

Processing stabilizers

• Thermal stabilizers – they are used in the case of polymers that tend to decompose at processing temperatures.
• Process antioxidants – they are used to prevent the oxidation of polymers, as well as the formation of post-transformation (e.g. branching) during processing.

The PCC Group’s offer includes a number of such substances in the form of products from the Rostabil series, which as additives have a wide range of applications in the plastics industry. These products have antioxidant properties, they can also act as thermal stabilizers, preventing degradation of plastics during processing. They are also used as process stabilizers. The Rostabil series has high hydrolytic stability, does not adversely affect the mechanical properties of materials and prevents degradation during thermal processes.

Processing modifiers

• Lubricants, dispersing and anti-adhesives – they reduce internal and external friction, which increases the plasticity of polymers. They also prevent adhesion of plastics to metal parts of forming devices. The Chemstat and Maxomer series is a group of professional additives that very well improve lubricating, antistatic and dispersing properties in the production of plastics. The PCC Group also offers a number of dispersants – Dyspergator series (R, RP, SBRP) – that allow the formation of latex dispersions that are stable during polymerization. These products are mainly used as auxiliary agents in the production of styrene-butadiene rubber (SBR) by emulsion polymerization. Dyspergator series of products (R, RP, SBRP) are compatible with other additives used in this process (e.g. emulsifiers and stabilizers), providing very good dispersion of the resulting latex particles in the aqueous phase. Another group of products are anti-adhesives, such as Chemax X-997 and Chemstat X-9910, which can also act as lubricants during the production of plastics.
• Corrosion inhibitors – additives that, even if used in small amounts, effectively reduce the corrosion rate of metals. The products Chemstat Cl-1020 and Chemstat Cl1020 / 60DC have been specially designed to prevent corrosion in the production of plastics, e.g. polyolefin granulates. The PCC Group’s offer includes both a powder product (Chemstat Cl1020 / 60DC) and a liquid (Chemstat Cl1020), due to which it can be used in many processes during the manufacture of such materials as Polypropylene and Polyethylene (HDPE and LLDPE).
• Fluidizing additives – they reduce the softening and flowing temperature of polymers. In contrast to greases, they have a low viscosity. Rodys series products (C, L, LP, O) are polymers of naphthalene sulfonic acid with formaldehyde, which thanks to their unique structure act as both emulsifiers and dispersants. Emulsifiers have a huge impact on the rheological properties of polymers, greatly improving them, which allows the reduction in the cost of production.
• Thixotroping agents – these additives are intended to increase or decrease the viscosity under the influence of plastic deformation. Plastics that have thixotropic properties under static conditions will be more sticky, resembling a solid (or vice versa, they will be in a liquid state). On the other hand, subjected to the process of mixing, shaking or other stress, they begin to “flow”, drastically reducing their viscosity (or become denser). Then after a set time they return to their original state. Typically, thixotropes include, but are not limited to, active silica, talc, ground glass.

Property modifiers

• Modifiers of optical properties – these are mainly colouring agents (dyes and pigments), brightening and matting agents.
• Flammability modifiers – these are flame retardants and anti-smokers. The products from the Roflam series are effective flame retardants and have a very weak influence on the physico-mechanical properties of polyurethane flexible foams. They are also characterized by low emission of volatile organic compounds. These products can be used in the furniture industry, for example for the production of armchairs, sofas, mattresses and pillows. Thanks to the content of phosphorus, they form a protective layer on the surface of the polymer, preventing the oxygen from reaching the flame and spreading it. The use of products from the Roflam series allows to obtain a good fire classification of building materials.
• Mechanical properties modifiers – they are plasticizers, impact modifiers, foaming agents and cross-linking agents. This product group includes the Roflex series, i.e. professional high viscosity plasticizers that are compatible with flame retardants from the Roflam They have many times better migration resistance compared to standard plasticizers based on traditional PVC formulations. Accessories from the Roflex series are widely used in construction (technical films, coverings), electronics (cable insulation), furniture (projection screens, artificial leather), automotive (car upholstery), as well as transport (conveyor belts and tarpaulins).
• Surface property modifiers – these are anti-statics, lubricants and anti-fogging agents, such as, for example, Chemstat® AF-322 and Chemstat® AF-687. Both products prevent steam formation and can be intended for indirect food contact according to the definition and limits set by the US Food and Drug Administration (FDA) – 21 CFR 178.3400 list. They have a wide range of applications in the packaging industry, food industry and plastics. Antistatic agents can be applied both internally (they are then connected to the polymer matrix) and externally to the surface of the polymer. The PCC Group offers a wide range of high-quality antistatic additives. Chemstat products can be used as anti-electrostatic in the production of many plastics, and thanks to their presence in various forms (solid, liquid or granulate) they are convenient in application.

Property stabilizers

• Metal deactivators – they prevent the oxidation of metal ions which occur in plastics at several degrees of oxidation.
• Stabilizers – they delay the degradation processes occurring in polymers, caused for example by the destructive effects of oxygen, temperature, ozone or other catalytic reactions leading to the disruption of the polymer chain. These changes have a direct impact on the processing and the appearance of finished products, e.g. changes in colour, gloss, shade of plastic. The PCC Group, in order to meet the customers’ expectations, offers a series of Rostabil products that can be used both as process and thermal stabilizers. They eliminate the effect of yellowing of materials during processing, enhance the colour stability of polymeric materials containing pigments and ensure transparency in non-pigmented materials.

The observed trends in the plastics industry

The plastics industry has undergone numerous changes in recent years. It is a huge sector, very fragmented (according to CSO research, it shows that in Poland over 2.8 thousand companies generate about 50% of revenues) and with great potential. In the plastics sector, a number of trends have been observed for several years.

The first one is based on material weight reduction, which is particularly evident in the automotive and construction industries. Plastics, thanks to their low weight and high strength, displace the steel elements used in the production of cars. In addition, thanks to the possibility of polymer modification using various additions, engineers can create specialized products dedicated to appropriate applications. A similar trend is occurring in the construction industry, where elements made of plastics replace traditional building materials, such as wood, steel or concrete, as well as in the construction of bridges, buildings and railway lines.

Another trend in the plastics sector is the use of biological and biodegradable polymers as an alternative to plastics produced from petroleum compounds. This is due to the fact that thermoset plastics, often used, for example, in cars, are very difficult to recycle. Of course, this directly affects the environment in a negative way. Currently, many companies are focusing on searching for alternative biological solutions that will be able to replace a number of hard-to-recycle petroleum materials. A recent example of this is a fully biodegradable material made of chitin.