First of all, local regulation, probably the most well-known blowing agent of XPS is Freon, some halocarbon including CFCs, HCFCs and HFCs. Every nationwide country provides its regulations about the use of Freon. In most created countries, HCFC is banned now, while in some developing countries like China, can use it until 2030 still, Indonesia may use it until 2040. But many countries are undertaking the new intend to speed up the phasing out schedule of HCFCs. One thing I must address is the fact that because of the poor solubility in polystyrene, CO2 cannot be used as blowing agent alone; it must be used with other co-blowing agent like ethanol collectively, butane or DME etc. as solvent to help CO2 solve into the polystyrene.
Secondly, source availability. In some countries, some kinds of blowing providers are not available. For instance, in a few Middle East countries, ethanol is not available and not allowed to import, which means you have to make use of something else to be alternatives. And in some countries, hFCs aren't available and not allowed to make use of actually, aside from HCFCs. You must consult with your specialist to see plastic compounding machines the source availability.
Finally, local insulation standard. Almost every nation has its own standard of thermal conductivity of XPS panel. Let's consider China; the China national standard of thermal conductivity of XPS is certainly 0.030. On the other hand, some countries don't use thermal conductivity as the standard; they use thermal level of resistance value or R worth rather. But how does the typical has something regarding your recipe of blowing agent? The good reason is that using different blowing agent can result in different thermal conductivity. For example, when you use HFCs or HCFCs, it is possible to control the lambda value below 0.029. Nevertheless if you are using CO2 plus ethanol, it really is hard to make the lambda worth under than 0.033. To get the lambda worth below 0.030, some ongoing companies are employing the combination of HFC, CO2 and ethanol.
The last issue, I'd prefer to talk about may be the relationship between thickness, hardness and the recipe of blowing agent. Using HFCs or HCFCs is simpler to obtain thickness like 15cm. If you use CO2 alone as the main blowing agent, it would be very hard to obtain such thickness unless your line can yield 1.5 ton each hour. But CO2 can be advisable once you produce high compressive strength panel like 1000kpa for special use, because CO2 provides smaller cell quantity which is beneficial to obtain finer cell structure of the board.
