Polyurethane-based insulation body and method for producing same

1. A process for producing an insulation body based on a fine- and open-celled polyurethane/polyisocyanurate foam in a cavity of a mold, comprising:

a. optionally inserting an optionally pre-molded insert into the cavity of the mold,

b. inserting a barrier film into the cavity or, if present, onto or into the insert,

c. applying a pressure of 8-30 bar in the cavity,

d. injecting a polyurethane reactive mixture containing supercritical CO 2 into the pressurized cavity,

e. decompressing to ambient pressure after a time of 1 to 40 seconds measured after the injection,

f. curing the polyurethane reactive mixture,

g. applying a vacuum of 0.001 mbar to 0.5 mbar in the cavity,

h. sealing any holes in the barrier film, and

i. demolding the resulting insulation body.

2. The process for producing an insulation body according to claim 1 , wherein a gas scavenger material is introduced between step b) and c) and/or between step f) and g).

3. The process for producing an insulation body as claimed in claim 1 , wherein the polyurethane reactive mixture comprises:

A) isocyanate-reactive component comprising:

A1) at least one polyol component having a functionality f of >2.5 selected from the group consisting of polyether polyols, polyester polyols, polycarbonate polyols, polyether polycarbonate polyols and polyether ester polyols, wherein the proportion of all primary OH functions present in the component A1) based on the total number of terminal OH functions in the component A1) is at least 30%,

A2) at least one catalyst component having Zerewitinoff-active hydrogens,

A3) at least one cell-opening compound,

A4) supercritical CO 2 ,

A5) optionally blowing agents with the exception of supercritical CO 2 , and

A6) optionally auxiliary and/or additive substances and

B) at least one polyisocyanate component,

wherein, relative to component A), component B) is present in an amount such that a ratio of the number of moles of NCO groups from component B) to the number of moles of OH groups from component A1) is 80 to 400.