Expaned PVC Foam Board Closed cell structure

PVC foam board is a foam composition with a closed cell structure, widely used in advertising panels, mounting board, silk screen, sculpture and so on. And some experience in the foam plant in the production process will inevitably encounter problems such as the production of PVC foam board bubble phenomenon. Today, Dongguan foam factory on the basis of more than 10 years experience in the bubble plant that PVC foam board bubble solution solution:

In the production process, the two effects may coexist, most of the hole is the local cell is not even after the expansion of the melt, the melt strength is reduced due to the strength of the melt itself is too low and the melt pressure is too small a lot of factors, To sum up, mainly in the following areas:

1. Foam melt has poor thermal stability, extrusion temperature setting or improper control

Solution: Extrusion operation, in addition to ensuring good melt plasticization, the extruder melt temperature must be lower than the blowing agent decomposition temperature, to prevent the blowing agent in the machine premature decomposition; Body temperature must reach the decomposition temperature of the blowing agent in order to facilitate the full foaming of the extrusion temperature setting and control, but also according to the vacuum hole material and the melt shape when the melt, the timely adjustment to ensure that the material in the Through the exhaust hole when the basic orange peel state, the bottom of the screw should not have powder flow; melt from the die when the surface should be smooth, there is a certain degree of flexibility, not an outlet die sagging or cross-section rough crystal.

2. The molecular weight or polymerization is too low

Solution: Production crust pvc foam board should use sc-7 resin, try not to use sc-8 type resin, or sc-8 type resin and sc-5 type or sc-6 type resin mixed.

3. improper addition of foaming agent

Solution: without affecting the foaming rate under the premise may be appropriate to add more heat-absorbing foaming agent, replace part of the exothermic foaming agent to inhibit the addition of exothermic foaming agent caused by the bubble .1232 or bla -616 foaming agent is an exothermic and endothermic balance of the blowing agent, decomposition without induction period, the decomposition rate is fast, about 10 minutes to reach the maximum amount of gas, deflated, no burst, the maximum amount of gas up to 156ml. The decomposition temperature is between pvc processing temperature range, can be used for thicker and complex shape of the product dynamic molding process, in order to eliminate the bubble, to ensure the stability of the foam performance.

4. Mold used improperly

Solution: different thickness crust pvc foam board production, must be the correct choice of mouth mold.

5. Poor quality of processing regulator or lack of dose

Solution: the production of different thickness of the plate, the processing regulator dose should also be different circumstances, the same formula, the thin plate without cells, thick plate cells, may be appropriate to add 0.3-0.5 copies of processing regulator, only Eliminate the bubble as a benchmark, trace add, avoid reckless consequences, blindly more, so as not to increase the density of products, affecting the effective production time.

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