Table of Contents
The extruder can be combined with various plastic forming auxiliary machines, such as pipes, films, support materials, monofilaments, flat wires, winding tapes, extrusion nets, plates, profiles, granulation, cable coating, etc., to form various plastic extrusion and forming lines to produce various plastic products.
The Applications of Extruder in Processing Industry
1. PET PLA PBAT Sheet Extrusion
Use in producing PET / PLA sheets, no need pre-drying crystallization of the energy consumption and adapt to the material for the production of the second, high yield, low energy consumption, high-quality plastics characteristics.
2. Long Glass Fiber Reinforced Thermoplastic Composites Impregnation Extrusion
It is not simply coating fibre tows with polymer, inside impregnation mould individual filaments in the fibre tows are spread apart so each is encapsulated with thermoplastic polymer.
3. Underwater Pelletizing
For example：
Reinforced modification: PP, PA, PBT, ABS, AS, PC, POM, PPS, PET, PPO, PSF, LCP add. Glass Fiber;
Filling Modification: PE, PP, EVA etc.+ talcum powder, titanium dioxide, carbon black;
Cable material: LDPE, HDPE, LLDPE, MDPE, sheath material, insulating material;
Blend alloy: PC+ABS, PA+ABS, CPE+ABS, PP+EPDM, PA+EPOM, PP+SBS;
Colour masterbatch: PE, ABS, PS, EVA, PET, PP+pigment, additive etc;
Flame retardant masterbatch:PP, PA, ABS, EVA, PBT+ flame retardant, additive etc;
Biodegradable masterbatch: PP, PE, PS+starch, additive etc.
4. Pipeline
Large size water supply lines for connection to water sources, water treatment plants and drinking water reservoirs, smaller size domestic water supply lines.
Large size mains for gas supply networks. Smaller size domestic gas supply lines.
Various types of panel and underfloor heating systems, hot and cold water installations, and acoustic drainage systems in buildings.
5. Cable pipe
The cable industry uses plastic tubing almost exclusively for the protection of power lines and cables used for data transmission, control systems and telecommunications systems against external shocks.
PVC is an extremely versatile material and is generally supplied as a dry (powder) mix, as in the case of PVC processing. The PVC compound is sensitive to shear and high temperatures, so it is gently processed with a parallel or conical twin-screw extruder, depending on the required output and pipe size.
The most commonly used 3-layer tube system is the core foam tube with a foam intermediate layer. The foam layer reduces the total weight of the pipe by 25 %. In addition, recycled material can often be used for the intermediate layer of core foam and solid wall tubes.
3-layer PVC pipes are now being used for a wide range of non-pressure applications such as drainage pipes and cable penetrations.
6. The Extruder Production of PE-Xa Pipe
PE-Xa (Peroxide crosslinked polyethene) has a very high degree of crosslinking and therefore excellent heat resistance. The manufacture of PE-Xa pipes requires a highly specialised process in which a blend of PE powder, liquid peroxide and stabiliser is melted and homogenised in a twin-screw extruder. To prevent early cross-linking, a low process temperature of 160°C is used for the compounding. Afterwards, the melt is moulded into a pipe blank in a pipe die with optimised flow properties and with a very small amount of special coating.
7. The Processing of Polyolefin
Polyolefins are generally supplied in the form of pellets. They are particularly suitable for single-screw extrusion because they are only moderately sensitive to shear and thermal stress.
8. The Modified and Prilling of Material
Extruders can be used for mixing, plasticising and granulating plastics, colouring and blending.
The plastic we normally use is not a pure substance, it is formulated from many materials. In addition, in order to improve the performance of the plastic, various auxiliary materials such as fillers, plasticisers, lubricants, stabilisers, colouring agents, etc. are added to the polymer in order to become a plastic with good performance.
The Applications of Screw Extruder in Food Industry
The most common type of extruder used in food processing is the co-rotating with fully meshed parallel twin-screw extruder. Screw extruders are mainly used in the food industry for the production of starch expanded food, protein extruded food, expanded feed and as special chemical or biochemical reactors.
Starch Puffed Food
Under the high temperature and pressure of the extruder, the starch in the grain will gelation. For example, when maize flour is puffed, the degree of starch gelation is above 98%, the crude fat is reduced by 60% or even disappears completely and the water solubility increases by more than 40%. This is why extruders can replace drum dryers for the production of dextrinised starch.
For Example：
Direct extrusion puffed products i.e. “ready-to-eat products”
Examples: puffed bars, puffed balls, cereals, bread
Indirect extrusion puffed products
The extrudate is puffed by using additional process steps such as microwave ovens, hot oil or hot air flow.
The Protein Extrusion Food
Under high temperature and pressure, plant proteins become organised. Under the action of shear between the screw groove and the barrel wall of the extruder, the proteins are strongly unfolded and arranged in a relatively straight line. The unfolded molecular chains become free and can be reoriented and recombined, thus forming a fibrous state. The fibrous structure is similar to that of lean meat, and when rehydrated has a certain elasticity and chewiness. It can be used to reorganise fish proteins such as minced fish and dried fishmeal to produce food products that mimic the flavour of prawns, snappers and chicken.
Puffing Fodder
In feed processing, extruders are mainly used to process whole soybean meal, maize starch, various kinds of cake meal, rice hulls, rice bran, egg shells and fish meal. The feeds produced include floating feeds for fish, high protein shrimp feeds, piglet feeds, chicken feeds feeds for pleasure animals, special aquatic feeds, etc.
Extruders produce puffed feeds with a variety of advantages, such as
- By extruding puffed full-fat soybeans, which inactivate anti-nutritional factors such as urease, improves the palatability and digestibility of soybean feed.
- A variety of oilseed cake meal rich in protein but also contains a certain amount of toxic components, extrusion puffing method can effectively detoxify and improve the digestibility and utilization of energy materials.
- After extrusion and puffing of rice hulls and rice bran, the shelf life can be extended by 10 times.
The Other Applications of Screw Extruder in Food Industry
- The extruder is a new type of biochemical reactor in which a series of biochemical reactions take place during the extrusion process. In addition to denaturing proteins, it also inactivates lipases, lipoxygenases, antitrypsin factors and naturally occurring toxic substances, and blunts the activity of enzymes that can cause food deterioration during storage, largely free of pathogenic bacteria, salmonella, insects and other contaminants.
- Replaces stirring reactors for the production of casein salt reactants for dairy products
- Replaces the boiler and mould pourer for the production of liquorice and fruit fudge.
- Replacement of the fine grinding machine for the production of chocolate
- Replacement of ovens for the production of baking sauces and caramels
- Instead of baking ovens for the production of sliced bread and biscuits;
- As a juicer for the production of various juices and oils.
The Applications of Screw Extruder in Pharmaceuticals Industry
Hot Melt Extrusion
Hot-melt extrusion technology allows polymeric materials to be processed above their glass transition temperature, leading to effective mixing of thermoplastic binders and/or polymers, and active ingredients at the molecular level.
This results in dust-free, continuous operation, good reproducibility and very high production efficiency.
The technology not only facilitates the dissolution of insoluble active ingredients and thus increases their bioavailability, but can also be used to delay the dissolution of water-soluble active ingredients for the preparation of slow-release or enteric formulations; in addition, the short duration of the extrusion process and the absence of the addition of water or organic solvents means that no heating and drying are required and hydrolysis is less likely to occur.
It is can be used in continuous mixing of pharmaceutical active ingredients
- Pharmaceutical Hot Melt Extrusion (HME)
- Solvent-free production of solid dispersions or solids solutions of APIs thus enhancing their bioavailability
- Hot Melt extrudates as the basis for solid dosage forms with controlled/sustained release of APIs
- Degassing of water to counteract API re-crystallisation(Encapsulation and taste masking)
Laboratory extruders (micro twin-screw extruders) are also available for processing small batches of pharmaceutical materials.
Pharmaceutical Plastic Packaging
In pharmaceutical packaging, plastics offer greater design flexibility and have replaced some of the traditional metal-based applications. In addition, plastics have developed more successful solutions to problems such as sterilisation and the abandonment of disposables, and technological innovations have enabled the market to grow by leaps and bounds. New developments, such as biocompatible plastics for implants, have led to a growing global market for pharmaceutical plastics.
The more common resins used in the pharmaceutical market include PVC, PE, PP and PET, with PVC also commonly used in pharmaceutical devices due to its softness.
The Other Applications of Screw Extruder
Screw extruders can also be used for other industrial products, such as the paper industry, the textile industry, metal casting, oil well drilling, etc.
