The present invention relates to a process for the production of a rigid polyurethane foam or rigid polyisocyanurate foam, comprising the reaction of at least one polyisocyanate and of a polyol composition (PZ), where the polyol composition (PZ) comprises at least one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound (I) selected from the group consisting of dicarboxylic diesters of dicarboxylic acids having from 2 to 18 C atoms and tricarboxylic triesters of tricarboxylic acids having from 3 to 18 C atoms, where at least one blowing agent is used during the reaction. The present invention further relates to rigid polyurethane foams or rigid polyisocyanurate foams obtainable or obtained by such a process, and also to a polyol composition (PZ) at least comprising one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound (I) selected from the group consisting of dicarboxylic diesters of dicarboxylic acids having from 2 to 18 C atoms and tricarboxylic triesters of tricarboxylic acids having from 3 to 18 C atoms. The present invention also relates to the use of such a polyol composition (PZ) for the production of rigid polyurethane foams or rigid polyisocyanurate foams, and also to the use of a rigid polyurethane foam or rigid polyisocyanurate foam of the invention as, or for the production of, insulation materials, preferably insulation sheets, sandwich elements, hot-water tanks, boilers, coolers, insulation foams, refrigerators or freezers.

The present invention discloses the production of panels by a discontinuous process. The panels are produced by injecting a polyisocyanurate foam forming composition into the mold cavity at reduced pressure. The combination of certain polyisocyanurate foam forming formulation and the reduced pressure in the mold cavity allows production of and resulting sandwich panels in a discontinuous process where the produced panels are characterized by improved fire resistance.

Provided is a method for producing a polyethylene-based resin extruded foam sheet by extruding and foaming a foamable molten resin composition formed by kneading a mixture containing a low-density polyethylene, a physical blowing agent, and an antistatic agent, wherein the foam sheet has a thickness in a range of from 0.05 to 0.5 mm, and the antistatic agent is a polymeric antistatic agent having a melting point whose different from the melting point of the low-density polyethylene is in a range of from 10 to +10 C., and having a melt flow rate of 10 g/10 min or more. This method enables a novel polyethylene-based resin extruded foam sheet to be obtained that is of high quality such that formation of a small hole or a through-hole has been reduced or eliminated, and has both excellent strength and a shock-absorbing property despite a very small thickness even in medium- or long-term continuous production, and besides, exhibits a sufficient antistatic property, thus suitable as a glass plate interleaf sheet.

The present invention relates to a process for the production of a rigid polyurethane foam or rigid polyisocyanurate foam, comprising the reaction of at least one polyisocyanate and of a polyol composition (PZ), where the polyol composition (PZ) comprises at least one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound (I) selected from the group consisting of dicarboxylic diesters of dicarboxylic acids having from 2 to 18 C atoms and tricarboxylic triesters of tricarboxylic acids having from 3 to 18 C atoms, where at least one blowing agent is used during the reaction. The present invention further relates to rigid polyurethane foams or rigid polyisocyanurate foams obtainable or obtained by such a process, and also to a polyol composition (PZ) at least comprising one compound having at least two hydrogen atoms reactive toward isocyanate groups and at least one compound (I) selected from the group consisting of dicarboxylic diesters of dicarboxylic acids having from 2 to 18 C atoms and tricarboxylic triesters of tricarboxylic acids having from 3 to 18 C atoms. The present invention also relates to the use of such a polyol composition (PZ) for the production of rigid polyurethane foams or rigid polyisocyanurate foams, and also to the use of a rigid polyurethane foam or rigid polyisocyanurate foam of the invention as, or for the production of, insulation materials, preferably insulation sheets, sandwich elements, hot-water tanks, boilers, coolers, insulation foams, refrigerators or freezers.