Abstract: The invention relates to a one-component reaction system for producing rigid polyurethane foams (also called rigid PUR foams) having improved dimensional stability, to methods for producing same and the use thereof. The invention also relates to the rigid polyurethane foams produced using the one-component reaction system according to the invention.

Abstract: The invention relates to a method for producing rigid polyurethane-polyisocyanurate (PUR/PIR) foams using partially trimerized isocyanate blends. The invention further relates to the rigid polyurethane-polyisocyanurate foams obtainable by said method and to the use thereof in manufacturing composite elements made of the rigid polyurethane-polyisocyanurate foams and suitable coatings. The invention also relates to the composite elements obtainable thereby.

Abstract: The present invention relates to a method for producing a PUR/PIR foam body, comprising the steps of providing a mold adapted for applying an underpressure to the interior of the mold; introducing a reaction mixture comprising an isocyanate-reactive component A and an isocyanate B into the mold, and applying an underpressure to the interior of the mold, so the underpressure acts on the introduced reaction mixture. The underpressure is applied to the interior of the mold no later than the reaction mixture has started to set in the mold, and the isocyanate index of the reaction mixture is ?300.

Abstract: The present invention relates to a process for producing a rigid polyurethane-polyisocyanurate foam C, comprising the step of reacting (i) an isocyanate-terminated prepolymer B with (ii) an activator component A comprising at least one trimerization catalyst A1 and at least one blowing agent A3 in a reaction mixture to form a foam, characterized in that—there is used an isocyanate-terminated prepolymer B obtained from a reaction of an isocyanate B1 having a mean isocyanate functionality of from ?2.3 to ?2.9 with a polyol component B2, and—the activator component A comprises water as the blowing agent A3 in an amount of from ?5 wt. % to ?50 wt. %,—the isocyanate index in the reaction mixture is in a range of from ?400 to ?500, and—the isocyanate content of the prepolymer B is in a range of from ?21 wt. % to ?30 wt. %, based on the total mass of the prepolymer B, and—wherein in the reaction of the prepolymer B and the activator component A a conversion contribution to polyisocyanurate of ?75% is achieved.

Abstract: The present invention relates to a method for producing a PUR/PIR foam body, comprising the steps of providing a mold adapted for applying an underpressure to the interior of the mold; introducing a reaction mixture comprising an isocyanate-reactive component A and an isocyanate B into the mold, and applying an underpressure to the interior of the mold, so the underpressure acts on the introduced reaction mixture. The underpressure is applied to the interior of the mold no later than the reaction mixture has started to set in the mold, and the isocyanate index of the reaction mixture is ?300.

Abstract: The present invention relates to a process for producing a rigid polyurethane-polyisocyanurate foam C, comprising the step of reacting (i) an isocyanate-terminated prepolymer B with (ii) an activator component A comprising at least one trimerisation catalyst A1 and at least one blowing agent A3 in a reaction mixture to form a foam, characterised in that—there is used an isocyanate-terminated prepolymer B obtained from a reaction of an isocyanate B1 having a mean isocyanate functionality of from ?2.3 to ?2.9 with a polyol component B2, and—the activator component A comprises water as the blowing agent A3 in an amount of from ?5 wt. % to ?50 wt. %,—the isocyanate index in the reaction mixture is in a range of from ?400 to ?500, and—the isocyanate content of the prepolymer B is in a range of from ?21 wt. % to ?30 wt. %, based on the total mass of the prepolymer B, and—wherein in the reaction of the prepolymer B and the activator component A a conversion contribution to polyisocyanurate of ?75% is achieved.

Abstract: The invention provides a process for producing rigid polyurethane-polyisocyanurate foams using polyols having a high proportion of secondary hydroxyl end groups. The invention further relates to the rigid polyurethane-polyisocyanurate foams thus obtainable and to the use thereof in the production of composite elements from rigid polyurethane-polyisocyanurate foams and suitable outer layers. The invention further provides the composite elements thus obtainable.

Abstract: The invention relates to a method for producing a water-blown polyurethane/polyisocyanurate rigid foam material that can be sprayed, by reacting a mixture comprising an aromatic polyester polyol, a first, comparatively short-chain aliphatic polyether polyol, a second, comparatively long-chain aliphatic polyether polyol, an isocyanate component, a blowing agent having water at least as a main component, and a catalyst component. The invention further relates to a rigid foam produced according to the method according to the invention, a composite material composed of said rigid foam and a pipe, and to the use of such a composite material for transporting liquid or gaseous media.