Hello dear, you have to reduce the foaming agent amount. I can not understand why do you talk about surfactant for this synthesis type.

Hello and 

Because I want to keep the density of the foam.I thought to change or decrease surfactant and catalyst .in your opinion I must decrease the water?

Thanks you 

Hello dear You have to reduce the water amount, because the water react with isocyanate producing CO2 and it increases the porosity. 

Ok, 

really, I will do it, and I see. 

Thanks dear Edwin

 Exactly right, yes, its much better.

But as ever, more dry?  it has no more elasticity?why?

Thank you so much

It depends very much on the foaming agent you use. If it is water you may chose a surfactant like TEGOSTAB B8433, if you use a mix of water amd physical foaming agent like pentane or a flourinated hydrocarbon you have to try with several types as their way and quality of action depend on the composition (ratio of water and hydrocarbon). Further, you have to adjust your catalytic system. In case of water only you may use a mixture of DABCO and tin dioctoate (usually 0.9 to 0.3 g /100 of A component), in case of mixing the foaming agents you have to adjust and use probably another catalytic system, e. h. including PC CAT TMG or PC CAT NP 50.

use higher activity surfactant or decrease water content