Modifying additives
Layers of plastic film have a tendency to stick to each other, which makes it harder to open plastic sleeves. This phenomenon is also visible when film is wound onto rollers.
Anti-blocking additives added to the plastic used to produce film reduce adhesion between the layers and make it easier to separate them. Using an appropriate anti-blocking additive makes the production process much easier.
We have a wide range of anti-blocking additives, from simple and economical solutions to carefully selected anti-blocking additives with a specific particle size for specialist applications We also have 2in1 solutions – slip additives with anti-blocking additives, which are often used because they make the manufacturing process easier.
PE/PP film is characterised by a high friction coefficient, which often makes it difficult to move the film on metal parts of machines.
The friction coefficient can be lowered by using appropriate slip additives.
Their effect is based on low compatibility with plastic. Over time, particles of the slip additive migrate towards the external layer of the film. In this way, slip additives modify the surface of the film and reduce friction during processing.
GM Color offers both fast blooming slip additives (which are important especially in the production of in-line bags) and slow blooming slip additives (used in two-stage processes, in which it is necessary to store intermediate products).
When two materials contact and there is friction, this can result in electrostatic charges. Electrostatic charges on the surface of plastics may make the production process significantly more difficult or have a negative impact on the future performance of the product.
Using anti-static additives makes it possible to limit or eliminate the undesired electrostatic effect. The most common problems caused by electrostatic charges include:
- excessive dust settling on finished products (which particularly relevant when goods are displayed in shops)
- static picked up by granules of plastics, colour masterbatches and additives in dispensers, feeding systems or storage places.
- electrostatic charges which may be dangerous for employees and cause a fire or an explosion
Active substances which can be used as antistatic agents are usually particles with a characteristic chemical structure. One part is hydrophylic and dissolves in water, whereas the second part is hydrophobic and has a higher affinity for the polymer matrix. Molecules of the antistatic agent migrate towards the surface of the polymer and are arranged in such a way that the hydrophylic part extends beyond the polymer matrix, whereas the hydrophobic part stays inside the plastic. In this way, the hydrophilic parts attract water molecules from the air, making it possible to create a very thin layer of water on the surface of the plastic. This extremely thin layer of water gives plastic products anti-static properties. In general, the higher the humidity, the more efficient the anti-static additive. Apart from standard anti-static additives, our range of products includes anti-static additives that work in low humidity.
In addition to standard antistatic additives, GM Color offers antistatic agents that work at low air humidity.
Plastics are exposed to oxidation, which can be caused by light or high temperatures. As a result, over time or even during processing, plastics may lose their mechanical properties and their surface may deteriorate visibly.
Antioxidants work by capturing free radicals responsible for the oxidative degradation of plastics, which extends the lifetime of the final product. Antioxidants are usually used wherever the final product is at risk of being exposed to high temperatures.
Antioxidants are also used as a component of mixes applied during machine downtime. When production is stopped, it often leads to the formation of gels. Moreover, plastic present in an excruder that has stopped running but is still cooling down often gets burnt. Starting up a line affected by the thermal degradation of plastic may be time-consuming and may generate unnecessary losses. Adding a small amount of antioxidant makes it possible to prevent the degradation of plastics and enables a seamless start-up after downtime.
Additives in which the active substance are fluoroelastomers. They are used in the manufacturing of LLDPE and LDPE film (both blown and cast), HDPE foil, pipe extrusion and in the process of injection blow moulding. The advantages of using process additives include:
- preventing the formation of deposits on the head,
- eliminating „shark skin effect”,
- limiting the formation of gels,
- obtaining a better quality surface,
- adding shine,
- lowering pressure and temperature in the extrusion process,
- making it easier to change colour.
GM Color has a wide range of process additives intended for different types of processes.
Plastics on the outside of buildings are exposed to various weather conditions, in particular sunlight. Natural sunlight causes irreparable damage to polymers. To ensure a long product life time, UV stabilisers should be used to protect plastics against premature degradation.
Choosing the right stabilising system depends on factors such as:
- the thickness of the element,
- the geographical region in which plastics are exposed to sunlight,
- the type of plastic,
- the presence of other components in the plastic (e.g. flame retardants).
Particular attention should be paid to the environment in which the finished product will be used. For example, film used in the agricultural sector is at risk of contact with pesticides and herbicides, which determines the choice of appropriate UV stabilisers.
Some production lines make use of water to cool polymer mass. Some production lines make use of water to cool polymer mass. It is an important factor which eliminates a large number of stabilisers from use due to their tendency to absorb moisture (WCO).
Apart from an extensive choice of UV stabilisers, GM Color also has a range of stabilising systems which have a minimal impact on WCO.
Under the influence of temperature, foaming agents decompose, leading to the formation of gas bubbles. Due to this process, the plastic structure becomes porous.
The application of foaming additives has many benefits:
- it eliminates sink marks and dents in moulded parts with ribs or near the point of injection,
- it limits plastic shrinkage,
- in some cases, it contributes to an increase in stiffness,
- it leads to an increase in insulation and suppression properties (heat, noise),
- it reduces the weight of the final product, making it possible to lower the cost of the final product.
GM Color has a range of additives with varying foaming capabilities and a range of products adjusted to different processing temperatures.
Chemical neutralisers of the unpleasant smell of plastic waste.
The melt flow index (MFI) is a very important parameter which determines the processing properties of plastics. Raising MFI is often the only way to manage a raw material whose melt flow index is too low.
Currently, GM Color can offer solutions for polypropylene.
Impact is the measure of crack resistance when the dynamic load is used. It is an important parameter which is controlled in particular in the production of regranulates. When a raw material with low resistance is used to manufacture regranulates, its resilience can be improved by adding a modifier.
Mineral fillers are used mainly to lower the manufacturing cost. Replacing some of the plastic with a filler makes it possible to generate significant savings without lowering the quality of the final product.
GM Color has a range of powder fillers and concentrates based on polymer carriers adjusted to the application.
A mineral filler in a polymer matrix is often more competitive than mineral filler powder. The advantages of concentrates include:
- easy dusting,
- quick mixing with the plastic which does not require any additional operations,
- very good homogenisation,
- easier dosing control.