DB22 Microcellular Foaming Efficiency in PVC Slippers and Mats

# DB22 Microcellular Foaming Efficiency in PVC Slippers and Mats > **What does foaming efficiency mean in a PVC slipper or mat?** Foaming efficiency is the ability of the plasticizer system to keep gelation, melt strength and blowing agent decomposition working in the same processing window, so that the foam expands to the intended density and then holds a fine, even cell structure. DB22 is designed for PVC foaming systems such as slippers, floor mats and foam boards, where plasticizing and foaming behaviour have to be balanced rather than optimized separately. The foaming ratio and process parameters should be confirmed through a trial on your own equipment. ## Why the plasticizer decides the cell structure In a chemically blown PVC foam, the plasticizer does more than soften the resin. It controls when the compound gels, how the melt behaves while the blowing agent is releasing gas, and how much the cell walls can stretch before they rupture. If gelation runs ahead of gas release, the compound is already too stiff to expand and the result is a dense skin with poor expansion. If the melt stays too soft, gas escapes through the surface and the cells coalesce into a coarse, uneven structure. A foaming plasticizer therefore has to be compatible enough to gel the resin cleanly, and slow enough to leave a usable processing window. That balance is what DB22 is formulated for. | Process variable | Direction that improves cell quality | What it controls | | :--- | :--- | :--- | | Plasticizer type | Good plasticizing and foaming compatibility | Gelation timing against gas release | | Plasticizer loading | Raised to suit foam density target | Melt viscosity and expansion ratio | | Blowing agent level | Matched to the plasticizer system | Gas volume available for expansion | | Mould or oven temperature | Set so decomposition sits inside the gelation window | Cell growth versus cell collapse | | Filler loading | Kept consistent between trials | Density, hardness and surface finish | ## Reading the foam: surface quality and resilience Two quality signals matter most on a slipper or a mat. The first is the surface: a fine, closed and even skin indicates that cells grew evenly and that the surface gelled at the right moment. The second is resilience and rebound, which reflects the uniformity of cell size through the thickness. A part can look acceptable on the surface while the core is coarse, which usually shows up later as a soft spot or a visible depression. DB22 is designed so that the plasticizing and foaming behaviours stay closely matched, which supports a dense and even cell structure and improves surface and resilience consistency under conventional foaming processes. | Formulation and process factor | Troubleshooting effect | Practical action | | :--- | :--- | :--- | | Plasticizer loading too low | Poor expansion, heavy part | Raise loading stepwise and re-check hardness | | Plasticizer loading too high | Sticky surface, collapse at the mould wall | Reduce loading, re-balance blowing agent | | Blowing agent too high | Coarse cells, blistered surface | Reduce level, verify decomposition profile | | Gelation too fast | Dense edge, uneven expansion | Adjust temperature profile or plasticizer blend | | Poor mixing | Localized defects, uneven density | Extend mixing time and check dispersion | ## Typical formulation approach for slippers and mats Slippers, floor mats and foam boards share a common starting structure: suspension PVC, a plasticizer package that carries the main loading, filler for cost and hardness control, a blowing agent, and a stabilizer and lubricant package to protect colour and release. | Component | Typical role | Notes for a foamed system | | :--- | :--- | :--- | | PVC resin | Matrix | Grade choice sets gelation behaviour | | DB22 (or a DB22 blend) | Plasticizing and foaming balance | Main lever on expansion and cell quality | | Filler (for example calcium carbonate) | Cost and hardness | Keep consistent between trials | | Blowing agent | Expansion | Decomposition temperature must suit the process | | Stabilizer and lubricant | Colour and release | Protects appearance through the heat history | Because DB22 is a proprietary in-house formulation with no public CAS Registry Number, the practical recommendation is always built from a trial: start from the loading that meets the hardness target, set the blowing agent to suit that melt viscosity, then tune the temperature profile until the surface and the core match the reference sample. ## Defect checklist for the moulding line | Defect | Most probable cause | Verify by | | :--- | :--- | :--- | | Coarse or open cells | Blowing agent too high or melt too soft | Reduce level, hold, and compare cut sections | | Compressed or glossy skin | Gelation too fast, low expansion | Check temperature profile and loading | | Uneven density side to side | Uneven dispersion or mould temperature | Mixing sequence and mould heating | | Shrinkage after demoulding | Insufficient curing or excess gas | Cure time and blowing agent level | | Colour variation | Heat history or stabilizer level | Temperature log and stabilizer package | ## Frequently asked questions **Can DB22 be used together with a general purpose plasticizer?** Yes. Blending is common where a foam compound has to meet both a density target and a cost target. The blend ratio is confirmed by trial. **Does a higher plasticizer loading always give a lower density part?** Only up to a point. Beyond the point where the melt loses strength, extra loading reduces cell stability and the part can collapse or take up water. **What should I check first when the foam looks correct but feels hard?** Check the actual density and the filler loading, then review the blowing agent level. Resilience is usually a density and cell uniformity question before it is a plasticizer question. **How long does a trial normally take?** A short trial series over three or four loadings, run on your own line, is normally enough to identify the working window. We can supply the trial material. ## Request a sample and a recommendation Our application team can review your current slipper or mat formulation and suggest a starting loading for DB22, supported by a 1kg complimentary testing sample dispatched worldwide via DHL or FedEx. Trial order MOQ is 1 MT, and bulk shipments are loaded as 23 MT flexitank containers from Ningbo or Shanghai.