In plastics, talcum powder of significant importance is a white, fine powder with a lamellar (sheet-like) structure. This special structure makes talc powder an effective reinforcing material. It improves rigidity and creep resistance of plastics at both normal and high temperatures. In addition, fine lamellar talc powder provides good solid gloss.
Effects of Talcum Powder on Plastic Properties
The addition of talc powder can change many plastic properties. These include molding shrinkage, surface hardness, flexural modulus, tensile strength, impact strength, heat distortion temperature, molding processability, and dimensional stability of products.
Application Features of Talcum Powder in Plastics
1. Economy
Talcum powder is only about 10%–20% of the price of plastics. Adding it effectively reduces material costs, especially when raw plastic prices continue to rise. This improves economic benefits. However, talc powder does not always reduce costs. In some cases, limited dosage or high-quality requirements may increase costs.
2. Improvement of Comprehensive Properties
Talcum powder improves multiple properties of plastics. Many effective properties are enhanced. For engineering plastics, it is often indispensable. Applications may require heat resistance, rigidity, hardness, flat surfaces, easy molding, or light weight.
3. Different Effects in Different Plastics
- In ABS and nylon: talc powder improves heat resistance and reduces molding shrinkage, besides economic benefits.
- In polyethylene: it mainly improves rigidity, heat resistance, shrinkage, and reduces costs.
- In polypropylene: it is most widely used and most effective. It improves overall strength, heat resistance, rigidity, and reduces shrinkage and cost. High-mesh talcum powder can also act as a nucleating agent in polypropylene, further enhancing comprehensive performance.
Methods of Using Talcum Powder
Direct Powder Addition
Talc powder is directly mixed with plastic resins. Then the mixture is extruded through a twin-screw extruder into modified plastic granules. This is the most common and economical method.
Carrier-Free Masterbatch Method
Talcum powder is processed into loose granules without a carrier. These are mixed with plastic resins and extruded into modified granules. This method reduces dust pollution and improves the working environment. It also prevents segregation between powder and granules, improves mixing uniformity, and enhances product quality.
Filler Masterbatch Method
Talcum powder is mixed with a plastic carrier and extruded into high-content masterbatches. These masterbatches can then be directly mixed with resins for extrusion or injection molding. This method is convenient, but dispersion is poor. It is unsuitable for high-quality products.
Notes on the Use of Talc Powder
Surface Treatment
Talcum powder must be surface-activated. Surface treatment improves compatibility between talc powder and plastics, enhancing modification effects. Different plastics require different treatment agents.
Dispersion in Plastics
Dispersion greatly affects the final properties of modified plastics. It is influenced by formulation, temperature, output, and processing conditions. For large addition amounts, a stepwise addition method may improve dispersion.
Proper Grade Selection
Different plastics and applications require different grades of talcum powder. The right choice ensures ideal results. Wrong selection may lead to opposite effects. Each plastic, product, and use condition has unique requirements, so the powder must be chosen carefully.
Epic Powder
In summary, talcum powder in plastic modification not only enhances comprehensive performance but also reduces costs and improves processability. To fully leverage its advantages, the right grade and surface treatment must be selected according to different plastics and application needs. With over 20 years of expertise in ultrafine powder technology, Epic Powder provides high-purity, ultrafine, and surface-modified talc powder processing equipment and integrated solutions, helping plastic manufacturers achieve both performance improvement and cost efficiency.
