GB2343181A

GB2343181A - A phenolic foam

Info

Publication number: GB2343181A
Application number: GB9823704A
Authority: GB
Inventors: Mark Stanley Harris; Graham Morgan Edgerley
Original assignee: Kingspan Industrial Insulation Ltd
Current assignee: Kingspan Industrial Insulation Ltd
Priority date: 1998-10-30
Filing date: 1998-10-30
Publication date: 2000-05-03
Also published as: GB9823704D0

Abstract

A phenolic foam including a phenol formaldehyde resin and a blowing agent has an amount of boric acid which is greater than 35 and ideally about 60 parts by weight of the resin. The foam includes acid catalyst(s) and surfactant(s). The addition of boric acid enhances the temperature characteristics of the foam.

Description

Title: A Product and Process Introduction This invention relates to a foam, especially a phenolic foam and to a process for preparing such foams.

Phenolic foams are widely used in building applications in view of their thermal insulation and fire resistant properties. Typically, such foams are prepared by mixing a phenol formaldehyde resin with a blowing agent, a cell stabiliser and a hardener.

One problem with such foams, however, is that they cannot be rated above a temperature of about 100 C. This is because the foam breaks down above this temperature. Thus, the range of applications for such foams is limited.

There is therefore a need for a foam which can be rated at higher temperatures and can then be used in a wider range of applications than has been possible to date.

Statements of Invention According to the invention there is provided a foam including a boroncontaining compound as a foam degradation inhibitor.

In a preferred embodiment of the invention the boron-containing compound is boric acid. The boron-containing compound may also be a salt of boric acid, such as sodium borate.

In a preferred embodiment of the invention the foam is a phenolic foam.

Preferably the foam is formed from a phenol formaldehyde resin and a blowing agent. In a preferred embodiment at least portion of the boroncontaining compound is contained in the resin.

Preferably the boron-containing compound is present in an amount of greater than 35 parts by weight of the phenolic resin component. Most preferably, the boron-containing compound is present in an amount of greater than 60 parts by weight.

Detailed Description The invention will be more clearly understood from the following description thereof.

The invention is based on the surprising finding that the high temperature stabilisation of phenolic foams can be greatly enhanced by using a boron-containing compound, especially boric acid as a foam degradation inhibitor.

We have found that by adding boric acid to a conventional phenolic foam formulation the temperature characteristics of the foam can be greatly enhanced. In particular, we have found that the incorporation of boric acid into the foam formulation at a level of approx 66 parts by weight of the resin produces a foam with a compressive strength that is maintained when aged at 140 C.

Example 1 Foams were manufactured in the laboratory using the formulations below. All amounts are parts by weight of the phenolic resin.

Foam A Foam B Phenolic Resin 100 100 HCFC 141 b 12 15 50% by weight Sulphuric acid 10 Surfactant Tegostab B8404-2 Surfactant Ethylan C40AH-2 81% by weight Phosphoric Acid 2 10 65% by weight Phenol Sulphonic-20 Acid Boric acid-66. 7 The phenolic resin is a standard low viscosity resin.

Tegostab is a silicone surfactant available from Goldschmidt.

Ethylan is an ethoxylated castor oil surfactant available for example from Akcros.

After de-moulding the compressive strength of the foams were tested with the following results.

Compressive strength of samples aged at 140 C

Dry density Initial 11 days 90 days % dif ka/-3 Foam A 30 177 141-20 99-44 58-67 Foam B 51 160 201 26 188 18 157 -2 Suitable blowing agents include HFC, HCFC, Pentane, methylene chloride and blends thereof. In addition, any organic compound boiling within the range-20 C to + 60 C is also likely to be suitable.

Suitable catalyst systems include mineral acids (such as sulphuric, phosphoric acids) and/or organic acids (such as phenol sulphonic, toluene sulphonic, xylene sulphonic and others.) The invention is not limited to the embodiments hereinbefore described which may be varied in detail.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

Claims 1. A foam including a boron-containing compound as a foam degradation inhibitor.
2. A foam as claimed in claim 1 wherein the boron-containing compound is boric acid.
3. A foam as claimed in claim 2 wherein the boron-containing compound is a salt of boric acid, such as sodium borate.
4. A foam as claimed in any preceding claim which is a phenolic foam.
5. A foam as claimed in claim 4 including a phenol formaldehyde resin and a blowing agent.
6. A foam as claimed in claim 5 wherein the boron-containing compound is present in an amount of greater than 35 parts by weight of the resin component.
7. A foam as claimed in claim 6 wherein the boron-containing compound is present in an amount of grater than 60 parts by weight.
8. A foam as claimed in any of claims 5 to 7 wherein at least portion of the boron-containing compound is contained in the resin.
9. A foam as claimed in any preceding claim including an acid catalyst.
10. A foam as claimed in claim 9 wherein the acid catalyst is a mineral acid such as sulphuric or phosphoric acids.
11. A foam as claimed in claim 9 wherein the acid catalyst is an organic acid such as phenol sulphonic, toluene sulphonic and/or xylene sulphonic.
12. A foam substantially as hereinbefore described.
13. Any novel feature or novel combination of features hereinbefore described.