Those Working in the Polyurethane Segment Know That Sedimentation Is Common in Some Formulated Polyols
Professionals in the polyurethane (PU) segment know that sedimentation is a frequent occurrence in some formulated polyols, even when the formulation includes a blowing agent (as blowing agents typically enhance solubility among components).
Proper mixing of formulated polyols is always recommended before handling, as some of these products contain more than ten components, and not all raw materials are mutually soluble.
The correct mixing of formulated polyol and isocyanate in polyurethane processing is essential for producing any type of foam. If the components are not mixed properly, the quality of the final product can be partially or even entirely compromised. Below, we will discuss the implications of improper mixing and the importance of ensuring a good mix in PU processing.
Consequences of Incorrect Mixing
When there are mixing errors, the final foam may exhibit:
- Irregular distribution of the reactions that form the PU polymer: The formation of the PU structure will be uneven and weakened. This irregular distribution can have significant effects on both flexible and rigid foams.
Flexible Foam Block: Irregular reaction distribution can result in:
- Loss of block height
- Internal cracks
- Compromised physical properties of the foam
The extent of these issues depends on the degree of mixing deficiency.
When this occurs, the quality and durability of the resulting foam will be inferior.
How to Achieve Proper Component Mixing
Having quality equipment is essential for successful PU production. If the manufacturer has access to low- or high-pressure injectors or continuous machines, for example, the performance of the produced PU can reach optimal levels of quality and productivity.
Due to PU’s versatility, it is also possible to produce foams using a high-speed electric agitator (or mixer). However, productivity will be lower compared to a machine, and production will be limited to smaller items. When using a mixer to produce foams, it is important to consider the following:
- Variable Frequency Drive (VFD): Using a mixer equipped with a VFD allows the operator to adjust the motor speed, ensuring efficient mixing for any foam density the company produces. Additionally, it is worth noting the temperature variations that commonly occur during production, which can increase or decrease the material’s viscosity. A VFD-equipped mixer enables better adjustments to accommodate different production scenarios.
What Care Should Be Taken with Equipment?
Although it may seem obvious, proper equipment cleaning is critical and positively impacts productivity. Here are some best practices:
- Thorough cleaning of equipment to remove raw material residues: Even a small particle of leftover material stuck to the equipment can contaminate and compromise future productions.
- Avoid using substances like petroleum jelly, grease, or similar products on mixing equipment: These substances can mix with the formulated material and contaminate the foam. The same applies to lubricants like oils or grease commonly used in machinery maintenance.
For more information about Amino Technology, contact us at +55 11 4077-3777 or send an email to: vendas@amino.com.br
