• Describe the toughest problems, difficulties, and red flags on the factory floor
• Clearly define performance improvement/efficiency goals
• Identify the time-consuming steps in the current work flow
It is incumbent upon compound service providers to spend time on the factory floor with plant chemists and mixing line operators to understand their goals and concerns to help them find and implement the solutions. Other topics at the mixing plant to be considered and addressed, including:
- Functional/Material Components: There are always questions about and a need to understand raw materials and their formulations. Raw materials include base polymers, fillers, vulcanizing agents, process aids, plasticizers, lubricants, curatives, accelerators and activators, protectants, colorants, blowing agents, and bonding agents (See the Material Component Overview).
- Forms of Components: Different form types, such as solids (e.g., slabs, bars, beads, and pellets), liquids, or pastes impact handling, mixing efficiency, environmental issues.
- Fabrication: Different fabrication methods, such as extrusion, injection molding, building and curing affect formulation requirements and performance additive selection.
- Financial Considerations: Performance additives cost more than powders, but improved processing, shorter mixing cycles, and increased throughput offset initial costs
Performance improvements, process efficiency goals, and total cycle cost reductions are what compounding service providers, such as HEXPOL Compounding, identify, evaluate, and strive to implement for their mixing customers. The price of performance additives is not going to be less expensive than powders (though only a small percentage of a formulation's cost), but process improvements and increased throughput contribute to lower total cycle costs as illustrated in (See Case Study A). That’s a major reason why plant chemists should constantly ask these types of questions when working with their compounding services provider. They should expect technical and application leadership.
Using dispersion performance additives, as shown in this case study, reduces the overall finished compound cost while improving quality and consistency. Improved efficiency leads to increased capacity.
Material Component Overview
Rubber Polymers - There are numerous grades of base polymers that vary in properties and cost. Select the right polymer for your application because rubber does not have universal, one- size-fits-all design criteria.
Fillers - Are available in several types: reinforcing, such as carbon black, semi-reinforcing, such as hard clay, and non-reinforcing, such as calcium carbonate. They help provide durability and performance in rubber compounds.
Plasticizers - They improve the rubber's flow during processing and enhance filler dispersion, and reduce compound viscosity.
Tackifiers - Provide short- and long-term tack in the compound that causes two layers to stick together with mild pressure. Tacky compounds don't always stick to other surfaces.
Process Aids - As the name implies, these chemicals improve the compound's precessability.
Internal Lubricants - Are mixed into the compound to keep the compound from sticking to process equipment and to lower heat build up.
Protectants - Include antioxidants that slow deterioration caused by contact with oxygen, antiozonants that slow deterioration caused by contact with ozone, and waxes, as well as metal deactivators and flame-retardants.
Accelerators - Hasten the chemical reaction and optimize the cross-linking reaction to speed up curing.
Activators - Strengthen accelerator performance and activate the vulcanization process.
Curatives - Sulfur, sulfur donors and other chemicals that cause cross-linking to occur.
Colorants - Are dispersions that eliminate cross-contamination of dry pigments, enhance color consistency across batch lots, reduce costs and increase product quality.
Blowing Agents - Produce gas by chemical or thermal action when added to a rubber com- pound in the manufacture of cell or sponge products.
Bonding Agents - They help hold dissimilar materials together in the nished rubber article.
Vulcanizing Agents - These agents provide the chemical process for converting rubber or related polymers into a more durable rubber-elastic material end product.
For more info on Performance Additives, visit http://hexpolperformanceadditives.com/.