Method for the production of a polyurethane sandwich element

Patent metadata

Field	Value
Publication number	US-2025263526-A1
Application number	US-202218702933-A
Country	US
Kind code	A1
Filing date	Oct 26, 2022
Priority date	Nov 3, 2021
Publication date	Aug 21, 2025
Grant date	—

Abstract

The invention relates to an isocyanate-reactive composition comprising an internal release agent, a method for production of a polyurethane sandwich element using the isocyanate-reactive composition, use of the isocyanate-reactive composition in the method for production of a polyurethane sandwich element and the polyurethane sandwich element.

First claim

1 . An isocyanate-reactive composition B comprising:
B1) at least one isocyanate-reactive component having at least two reactive hydrogen atoms; and B2) more than 5.0 to less than 9.0 wt % of an internal mold release, based on the amount of isocyanate-reactive composition B, wherein the internal mold release comprises:
B2a) a first internal mold release agent; and
B2b) a second internal mold release agent which is a fatty acid and different from B2a.

2 . The isocyanate-reactive composition B of claim 1 wherein the first internal mold release agent B2a is a fatty acid ester.

3 . The isocyanate-reactive composition B of claim 1 , wherein the amount of the first internal mold release agent B2a is 2.0-8.0 wt %, based on the amount of isocyanate-reactive composition B.

4 . The isocyanate-reactive composition B of claim 1 , wherein the amount of the second internal mold release agent B2b is 0.50-6.0 wt %, based on the amount of isocyanate-reactive composition B.

5 . The isocyanate-reactive composition B of claim 1 , wherein the amount of B2 internal mold release is 5.5-8.5, wt %, based on the amount of isocyanate-reactive composition B.

6 . The isocyanate-reactive composition B of claim 1 , wherein the at least one isocyanate-reactive component having at least two reactive hydrogen atoms B1 comprises:
B1a) a polyether polyol with an OH number of 700-1000 mg KOH/g and a functionality of 2.0-4.0, obtained by addition of an alkylene oxide to an alcohol; B1b) a polyether polyol with an OH number of 300-600 mg KOH/g and a functionality of 3.0-6.0, obtained by addition of an alkylene oxide to a starter compound, wherein the starter compound comprises at least one of a carbohydrate, a bifunctional alcohol that is not a carbohydrate, or a mixture of the foregoing; and B1c) a polyether polyol different from B1b with an OH number of 250-550 mg KOH/g and a functionality of 2.0-4.0, obtained by addition of an alkylene oxide to an alcohol.

7 . A method for producing a polyurethane sandwich element, comprising the steps of:
i. applying a first fiber material having a first surface and a second surface to a first surface of a core material; ii. applying a second fiber material having a first surface and a second surface to a second surface of the core to form a sandwich structure having a first and a second surface wherein the first and second fiber material may be the same or different; iii. applying a polyurethane-forming mixture comprising an isocyanate composition and a isocyanate-reactive composition to the first and the second surface of the sandwich structure so that the first and the second surface of the sandwich structure are at least partly covered by the polyurethane-forming mixture to form a polyurethane-forming mixture covered sandwich structure and placing the sandwich structure into a mold, wherein applying the polyurethane-forming composition may take place before, during or after placing the sandwich structure into a mold; iv. curing the polyurethane-forming mixture to form the polyurethane sandwich element; v. removing the sandwich element from the mold; and vi. optionally, post-treating the sandwich element; wherein the polyurethane-forming mixture comprises:
A) an isocyanate composition; and
B) the isocyanate-reactive composition of claim 1 .

8 . The method of claim 7 , wherein the isocyanate composition A comprises polymeric MDI with an NCO content of 30 to 33 wt % and a content of monomeric MDI of at least 20 wt %.

9 . The method of claim 7 , wherein the core material comprises a honeycomb paperboard, a plastic honeycomb, aluminum honeycomb, balsa wood, a rigid foam, compressed or uncompressed cotton fibers, compressed or uncompressed natural fibers, or compressed or uncompressed plastic fibers, or a combination of the foregoing.

10 . The method of claim 7 , wherein the first fiber material and second fiber material are independently at least one of a reinforcing fiber material, a woven fiber mat, a non-woven fiber mat, a continuous strand fiber, a fiber random structure, a fiber tissue, chopped fibers, ground fibers, a knitted fabric, or a combination of the foregoing.

11 . The method of claim 7 , wherein the first fiber material and second fiber material independently comprise at least one of carbon fibers, polymeric fibers, aramide fibers, mineral fibers, glass fibers, natural fibers, or a mixture of the foregoing.

12 . A polyurethane sandwich element obtained by the method of claim 7 .

13 . (canceled)

14 . A polyurethane produced from the isocyanate-reactive composition according to claim 1 .

15 . A polyurethane sandwich element comprising the polyurethane of claim 14 .

16 . The isocyanate-reactive composition B of claim 3 , wherein the amount of the first internal mold release agent B2a is 4.0-7.0 wt %, based on the amount of isocyanate-reactive composition B.

17 . The isocyanate-reactive composition B of claim 4 , wherein the amount of the second internal mold release agent B2b is 1.0-4.0 wt %, based on the amount of isocyanate-reactive composition B.

18 . The isocyanate-reactive composition B of claim 5 , wherein the amount of B2 internal mold release is 6.0-8.0 wt %, based on the amount of isocyanate-reactive composition B.

19 . The method of claim 8 , wherein the isocyanate composition A consists of polymeric MDI with an NCO content of 30 to 33 wt % and a content of monomeric MDI of at least 20 wt %.

20 . The method of claim 8 , wherein the isocyanate composition A comprises polymeric MDI with an NCO content of 30 to 33 wt % and a content of monomeric MDI of at least 30 wt %.

Assignees

• Covestro Deutschland Ag

Inventors

• Reithmeier Richard
• Hoffmann Andreas
• Niederelz Heike
• Rasselnberg Harald
• Kraus Thorsten Josef

Classifications

• C08K5/101

  of monocarboxylic acids · CPC title

• C08K5/09

  Carboxylic acids; Metal salts thereof; Anhydrides thereof · CPC title

• C08J2375/08

  from polyethers · CPC title

• C08G18/7671

  containing only one alkylene bisphenyl group · CPC title

• C08G18/6674

  with compounds of group C08G18/3203 · CPC title