Method for the vacuum-assisted production of a PUR/PIR foam body

Patent metadata

Field	Value
Publication number	US-9950454-B2
Application number	US-201314418251-A
Country	US
Kind code	B2
Filing date	Jul 29, 2013
Priority date	Jul 31, 2012
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

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.

First claim

What is claimed is:

1. 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;
applying an underpressure to the interior of the mold, so the underpressure acts on the introduced reaction mixture;
wherein the following consecutive moments are defined in the method:
t0: the reaction mixture has started to be introduced into the mold
tL: the reaction mixture has started to expand in the mold
tA: the reaction mixture has started to set in the mold
tF: the expanded reaction mixture has finished filling the mold
wherein the isocyanate index of the reaction mixture is ≥300, and
wherein the underpressure is applied before tA, and
≥50% to ≤80% of the total period for which the underpressure is applied, is before tA.

2. The method as claimed in claim 1 , wherein applying the underpressure is terminated before tF.

3. The method as claimed in claim 1 , wherein applying the underpressure is terminated at tF or after tF.

4. The method as claimed in claim 1 , wherein the isocyanate index of the reaction mixture is ≥300 to ≤500.

5. The method as claimed in claim 1 , wherein the underpressure is applied for a total period of ≥5 seconds to ≤180 seconds.

6. The method as claimed in claim 1 , wherein the underpressure is ≥0.01 bar to ≤0.95 bar.

7. The method as claimed in claim 1 , wherein the magnitude of the applied underpressure is temporally variable.

8. The method as claimed in claim 1 , wherein the introducing of the reaction mixture into the mold is effected such that the reaction mixture comes into contact with at least one article that is present in the mold and differs from the mold.

9. The method as claimed in claim 8 , wherein the at least one article is a hollow body and the reaction mixture is in the interior of the hollow body.

10. The method as claimed in claim 8 , wherein the reaction mixture is between two face layers.

11. The method as claimed in claim 8 , wherein the reaction mixture is on the outside surface of a pipe.

12. The method as claimed in claim 1 , wherein the flow index of the reaction mixture after application of the underpressure is ≥1.0 to ≤1.3.

Assignees

• Covestro Deutschland Ag

Inventors

• Albers Reinhard
• Klasen Patrick
• Vogel Stephanie

Classifications

• Y10T428/1376

  Foam or porous material containing · CPC title

• B29K2075/00

  Use of {PU, i.e.} polyureas or polyurethanes {or derivatives thereof}, as moulding material · CPC title

• B29K2079/00

  Use of polymers having nitrogen, with or without oxygen or carbon only, in the main chain {, not provided for in groups B29K2061/00 - B29K2077/00}, as moulding material · CPC title

• B29L2007/00

  Flat articles, e.g. films or sheets (B29L2024/00 takes precedence) · CPC title

• B29L2023/00

  Tubular articles (B29L2024/00 takes precedence {; catheters B29L2031/7542}) · CPC title