GB2359085A

GB2359085A - Thermal insulation material

Info

Publication number: GB2359085A
Application number: GB0003262A
Authority: GB
Inventors: Andrew John Smith; William Henry Player
Original assignee: Winn and Coales International Ltd
Current assignee: Winn and Coales International Ltd
Priority date: 2000-02-11
Filing date: 2000-02-11
Publication date: 2001-08-15
Also published as: GB0003262D0; WO2001058995A1; AU3206601A

Abstract

A material for thermal insulation which comprises a phenolic resin, is characterised in that one or more fillers and one or more minerals are included as additives during synthesis of the phenolic resin. The one or more fillers are selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides, and the one or more minerals are selected from the group consisting of silicate glass, mica, igneous rock and minerals derivable from igneous rock. Processes for production of such a material and its use as a fire retardant material are also described.

Description

THERMAL INSULATION MATERIAL The present invention concerns novel thermal insulation materials, processes for the production of such materials and uses of such materials.

Thermal insulation materials may be usefully employed in a very wide variety of applications which require the maintenance of a temperature differential between two regions. For example, they may be used to manufacture heat resistant coatings, cold storage containers or fireproof structures.

In the past, asbestos has been used as a thermal insulation material in a wide variety of applications. However, since the discovery of the carcinogenic nature of asbestos, there has been a particular need for the development of thermal insulation materials suitable for its replacement.

Phenolic resins are a class of polymers which are well known to those skilled in the art and they have been used in a variety of products which are subject to severe conditions such as heat-resistant surfaces, electrical insulators and flame-retardant composites. It should be noted that, within the context of the present specification the term "phenolic resin" refers to the final cured form of the resin rather than intermediate partially polymerised resins. The intermediate resins are referred to herein by the term "phenolic resin prepolymer".

Phenolic resins result from the interaction of phenolic compounds and aldehydes. There are various routes by which phenolic resins may be synthesised and the present invention is not intended to be limited to any particular one. However, by way of explanation and The choice of aldehyde or aldehyde precursor to be included in the phenolic resin precursor composition will depend upon the desired properties of the resultant resin.

Other reactants may optionally be included in the phenolic resin precursor composition to provide phenolic resins with specific properties. Examples of other additives include: aniline, rosin, dicyclopentadiene, unsaturated oils such as tung oil and linseed oil, and polyvalent cations for cross- linking.

It would be advantageous to provide a material based on a phenolic resin which exhibits improved thermal insulation properties.

Accordingly, the present invention provides a material for thermal insulation which comprises a phenolic resin, characterised in that one or more fillers and one or more minerals are included as additives during synthesis of the phenolic resin, the one or more fillers being selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides; and the one or more minerals being selected from the group consisting of silicate glass, mica, igneous rock and minerals derivable from igneous rock.

Preferably, the one or more fillers and the one or more minerals are mixed with a phenolic resin prepolymer prior to curing the phenolic resin prepolymer so as to synthesise the phenolic resin. The phenolic resin prepolymer may be either a novolak or resole resin. An example of a suitable phenolic resin prepolymer is the phenol formaldehyde resole resin P963 supplied by Borden Chemical UK Ltd. examples of hardeners. The mixture may also be heated to accelerate the cross-linking process. The novolak curing reaction may involve a catalyst such as magnesium or calcium oxide and may also involve the use of certain metal salts, such as zinc, magnesium or calcium acetates. Resoles do not require the addition of a catalyst or other additive and may be cured (cross-linked) simply by heating the prepolymer. However, acid catalysis may be used to accelerate the hardening of resole resins.

Phenol itself is the most common phenolic compound to be used in phenolic resin precursor compositions. However, other aromatic hydroxyl compounds may also be used such as, for example, catechol (1,2-dihydroxy- benzene), resorcinol (1,3-dihydroxy-benzene), quinol (1,4-dihydroxy-benzene), cresol (methylphenol, including 3-methylphenol and 4-methylphenol), xylenol (dimethylphenol), p-t-butylphenol, p-phenylphenol, diphenols and bisphenol A. The choice of phenolic compound to be included in the precursor composition will depend upon the desired properties of the resultant resin. For example the incorporation of alkyl phenols into the precursor composition provides a resin with reduced reactivity, hardness, cross-link density and colour formation but increased solubility in non-polar solvents, flexibility and compatability with natural oils.

Formaldehyde, principally in its hydrated form, is the most common aldehyde compound to be used in phenolic resin precursor compositions because of its high reactivity. However, other aldehyde compounds may also be used such as, for example, ethanal, benzaldehyde or furfuraldehyde. The aldehyde component may alternatively be provided by a latent source of aldehyde such as, for example, hexarnethylenetetramine. acid such as the product P964 supplied by Borden Chemical UK Ltd.

A very wide variety of materials may also be included as additives during the synthesis of the phenolic resin in order to provide composite materials which exhibit particular chemical and/or physical properties. Thus in further embodiments of the present invention one or more materials selected from the group consisting of glass fibre, carbon fibre and metal particles such as aluminium trimite may also be included as additives during synthesis of the phenolic resin.

The present invention also includes within its scope a material for thermal insulation which comprises: (i) one or more fillers selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides, (ii) one or more minerals selected from the group consisting of silicate glass, mica, igneous rock and minerals derivable from igneous rock, and (iii)a cured phenolic resin in an amount sufficient to bind components (i) and (ii). As stated earlier, even very small quantities of filler(s) and mineral (s) can provide improvements in the thermal insulation properties of phenolic resins. However, in a preferred embodiment the material comprises a cured phenolic resin in an amount of from 10 to 90 wto, one or more fillers in an amount of from 5 to 60 wto and one or more minerals in an amount of from 5 to 60 wt o, based on the total weight of the composite material.

More preferably, the material comprises a cured Improvements in the thermal insulation properties of a phenolic resin can be obtained even by the use of very small amounts of filler(s) and mineral(s) as additives during the synthesis of the phenolic resin. However, in a preferred embodiment, the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 10 to 90 wt%, one or more fillers in an amount of from 5 to 60 wt% and one or more minerals in an amount of from 5 to 60 wt%, based on the total weight of the mixture.

More preferably, the mixture prior to curing comprises phenolic resin prepolyrner in an amount of from 40 to 80 wt%, one or more fillers in an amount of from 10 to 30 wt% and one or more minerals in an amount of from 10 to 30 wt%, based on the total weight of the mixture.

Even more preferably, the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 60 to 70 wt%, one or more fillers in an amount of from 15 to 20 wt% and one or more minerals in an amount of from 15 to 20 wt%, based on the total weight of the mixture.

As mentioned in the discussion of phenolic resin synthesis above, some phenolic resin prepolymers require a hardener in order to cure them to provide the final phenolic resin. Thus the mixture prior to curing may also comprise a hardener. The hardener is preferably present in an amount of from 5 to 20 wt% based on the total weight of the mixture. Even where a hardener is not required an acid catalyst may optionally be used, preferably in an amount of from 5 to 20 wt% based on the total weight of the mixture. An example of a suitable acid catalyst is an aqueous mixture of p-toluene sulphonic acid and phosphoric an amount of from 5 to 30 wt%, magnesia in an amount of from 0.05 to 30 wt% and ferric oxide in an amount of from 0.05 to 10 wt%, based on the total weight of the mineral.

A preferred mineral which comprises silica, alumina, magnesia and ferric oxide is perlite. Perlite is a volcanic glassy rock which has a concentric or onion- like structure and a pearly lustre. It usually comprises silica in an amount of from 65 to 75 wt%, alumina in an amount of from 9 to 20 wt%, magnesia in an amount of from 0.05 to 1 wt% and ferric oxide in an amount of from 0.05 to 3 wt%, based on the total weight of the mineral. It may also comprise small amounts (i.e. less than 5 wt%) of a number of other oxides such as, ferrous oxide, lime, soda, potash, titanium dioxide phosphorous pentoxide and manganous oxide. Perlite may also contain up to approximately 6 wt% water which causes it to expand to a considerable extent upon heating. In the present invention the perlite is preferably used in its expanded form. Another preferred mineral which comprises silica, alumina, magnesia and ferric oxide is vermiculite. Vermiculite has a platy, laminated structure and it usually comprises silica in an amount of approximately 40 wt%, alumina in an amount of approximately 15 wt%, magnesia in an amount of approximately 25 wt% and ferric oxide in an amount of approximately 5 wt%, based on the total weight of the mineral. It may also contain from 4 to 14 wt% water which also causes it to expand to a considerable extent upon heating. In the present invention the vermiculite is preferably used in its expanded form.

The material of the present invention exhibits excellent properties as a fire retardant material. In phenolic resin in an amount of from 40 to 80 wt%, one or more fillers in an amount of from 10 to 30 wt% and one or more minerals in an amount of from 10 to 30 wt%, based on the total weight of the composite material.

Even more preferably, the material comprises a cured phenolic resin in an amount of from 60 to 70 wt%, one or more fillers in an amount of from 15 to 20 wt% and one or more minerals in an amount of from 15 to 20 wt%, based on the total weight of the composite material.

The material may also comprise one or more materials selected from the group consisting of glass fibre, carbon fibre and metal particles such as aluminium trimite.

Preferably, the filler is selected from one or more of hydrated calcium sulphate (commonly called gypsum), calcium sulphate hemihydrate, anhydrous calcium sulphate and calcium oxide (commonly called lime or limestone).

When silicate glass is present as the mineral component it may be in the form of a fine powder, short strands, spheres or flakes.

When mica is present as the mineral component it may be in the form of natural or synthetic mica.

When igneous rock or a mineral derivable from igneous rock is present as the mineral component it is preferably a mineral which comprises silica, alumina, magnesia and ferric oxide. Even more preferably it includes these components in the following amounts: silica in an amount of from 20 to 80 wt%, alumina in application. The present invention also includes within its scope a process for forming a thermal insulation material comprising mixing a phenolic resin prepolymer with one or more fillers selected from the group consisting ofalkaline earth metal sulphates and alkaline earth metal oxides, and with one or more minerals selected from the group consisting of silicate glass, mica, igneous rock and minerals derivable from igneous rock, and curing the mixture so as to convert the phenolic resin prepolymer into a phenolic resin.

The present invention is further described by way of the following example.

Example 1 1 kg of phenol-formaldehyde phenolic resin prepolymer (Borden Resin P963) was mixed with 0.5 kg of a mixture of 49.75 wto gypsum powder, 49.75 wto perlite granules and 0.5 wto glass powder. To this mixture was added 0.1 kg of hardener (Borden Hardener P964). The mixture was placed in a mould and the mould was placed in an oven for 1 hr at 60 C. this regard the material is found to satisfy the three major criteria for fire retardant materials. That is to say, the material is very resistant to heat, it is non-flammable and it does not produce harmful fumes when exposed to heat and/or flame. Prior to the present invention, known fire retardant materials have usually addressed only one or two of these three requirements.

Furthermore, the material of the present invention also exhibits other properties which make it very suitable for a wide variety of industrial uses. In particular, the material shows excellent thermal insulation efficiency which is not only beneficial in its use as a fire retardant but also makes it suitable for protection against severe cold temperatures or for maintaining any desired temperature, such as the accurate control of sustained liquid temperatures within pipelines. The material is very light and strong and may be readily handled and cut. It is fully mouldable into any desired shape and it does not shrink, expand or distort when exposed to very low and/or very high temperatures. The material is also extremely resistant to common industrial chemicals such as detergents, oils, petrochemicals, acids and alkalis. It is not affected by UVA radiation and it is non-soluble in common solvents and impervious to water. Finally, it will seal a wide range of known construction and manufacturing materials and is therefore suitable for use as a thermally insulating and/or fire retardant sealing or cladding material.

In common with known phenolic resins the material may be shaped and processed by methods known in the art such as compression moulding, injection moulding, sheet forming, vacuum forming, extrusion, fibre spinning, wet lay-up, spray application and trowel to 80 wt%, one or more fillers in an amount of from 10 to 30 wt% and one or more minerals in an amount of from 10 to 30 wt% based on the total weight of the mixture.

7. A material as claimed in any one of claims 2 to 4 wherein the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 60 to 70 wt%, one or more fillers in an amount of from 15 to 20 wt% and one or more minerals in an amount of from 15 to 20 wt% based on the total weight of the mixture.

8. A material as claimed in any one of claims 5 to 7 wherein the mixture prior to curing also comprises a hardener in an amount of from 5 to 20 wt% based on the total weight of the mixture.

9. A material as claimed in claim 8 wherein the hardener is an aqueous mixture of p-toluene sulphonic acid and phosphoric acid.

10. A material as claimed in any one of claims 1 to 9 wherein one or more materials selected from the group consisting of glass fibre, carbon fibre and metal particles are also included as additives during synthesis of the phenolic resin.

11. A material for thermal insulation which comprises (i) one or more fillers selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides, (ii) one or more minerals selected from the group consisting of silicate glass, mica, igneous rock and minerals derivable from igneous rock, and (iii)a cured phenolic resin in an amount

Claims

CLAIMS: 1. A material for thermal insulation which comprises a phenolic resin, characterised in that one or more fillers and one or more minerals are included as additives during synthesis of the phenolic resin; the one or more fillers being selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides, and the one or more minerals being selected from the group consisting of silicate glass, mica, igneous rock and minerals derivable from igneous rock.
2. A material as claimed in claim 1 wherein the one or more fillers and one or more minerals are mixed with a phenolic resin prepolymer prior to curing the phenolic resin prepolymer so as to synthesise the phenolic resin.
3. A material as claimed in claim 2 wherein the phenolic resin prepolymer is a novolak resin.
4. A material as claimed in claim 2 wherein the phenolic resin prepolymer is a resole resin.
5. A material as claimed in any one of claims 2 to 4 wherein the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 10 to 90 wt%, one or more fillers in an amount of from 5 to 60 wt% and one or more minerals in an amount of from 5 to 60 wt% based on the total weight of the mixture.
6. A material as claimed in any one of claims 2 to 4 wherein the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 40 comprises silica in an amount of from 20 to 80 wt%, alumina in an amount of from 5 to 30 wt%, magnesia in an amount of from 0.05 to 30 wt% and ferric oxide in an amount of from 0.05 to 10 wt%, based on the total weight of the mineral. 18. A material as claimed in any one of claims 1 to 17 wherein the mineral is expanded perlite. 19. A material as claimed in any one of claims 1 to 17 wherein the mineral is expanded vermiculite. 20. Use of a material as claimed in any one of claims 1 to 19 as a fire retardant material. 21. A process for forming a thermal insulation material comprising mixing a phenolic resin prepolymer with one or more fillers selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides and with one or more minerals selected from the group consisting of silicate glass, mica, igneous rock and minerals derivable from igneous rock and curing the mixture to convert the phenolic resin prepolymer into a phenolic resin. sufficient to bind components (i) and (ii). 12. A material as claimed in claim 11 which comprises a cured phenolic resin in an amount of from 10 to 90 wt%, one or more fillers in an amount of from 5 to 60 wt% and one or more minerals in an amount of from 5 to 60 wt%, based on the total weight of the resin. 13. A material as claimed in claim 11 which comprises a cured phenolic resin in an amount of from 40 to 80 wt%, one or more fillers in an amount of from 10 to 30 wt% and one or more minerals in an amount of from 10 to 30 wt%, based on the total weight of the resin. 14. A material as claimed in claim 11 which comprises a cured phenolic resin in an amount of from 60 to 70 wt%, one or more fillers in an amount of from 15 to 20 wt% and one or more minerals in an amount of from 15 to 20 wt%, based on the total weight of the resin. 15. A material as claimed in any one of claims 11 to 14 which further comprises one or more materials selected from the group consisting of glass fibre, carbon fibre and metal particles. 16. A material as claimed in any one of claims 1 to 15 wherein the one or more fillers are selected from the group consisting of hydrated calcium sulphate, calcium sulphate hemihydrate, anhydrous calcium sulphate and calcium oxide. 17. A material as claimed in any one of claims 1 to 16 wherein the mineral is igneous rock or a mineral derivable from igneous rock which to 80 wt%, one or more fillers in an amount of from 10 to 30 wt% and one or more minerals in an amount of from 10 to 30 wt% based on the total weight of the mixture.
7. A material as claimed in any one of claims 2 to 4 wherein the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 60 to 70 wt%, one or more fillers in an amount of from 15 to 20 wt% and one or more minerals in an amount of from 15 to 20 wt% based on the total weight of the mixture.
8. A material as claimed in any one of claims 5 to 7 wherein the mixture prior to curing also comprises a hardener in an amount of from 5 to 20 wt% based on the total weight of the mixture.
9. A material as claimed in claim 8 wherein the hardener is an aqueous mixture of p-toluene sulphonic acid and phosphoric acid.
10. A material as claimed in any one of claims 1 to 9 wherein one or more materials selected from the group consisting of glass fibre, carbon fibre and metal particles are also included as additives during synthesis of the phenolic resin.
11. A material for thermal insulation which comprises (i) one or more fillers selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides, (ii) one or more minerals selected from the group consisting of mica, igneous rock and minerals derivable from igneous rock, and (iii)a cured phenolic resin in an amount <B>Amendments to the claims have been filed as follows</B> CLAIMS: 1. A material for thermal insulation which comprises a phenolic resin, characterised in that one or more fillers and one or more minerals are included as additives during synthesis of the phenolic resin; the one or more fillers being selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides, and the one or more minerals being selected from the group consisting of mica, igneous rock and minerals derivable from igneous rock. 2. A material as claimed in claim 1 wherein the one or more fillers and one or more minerals are mixed with a phenolic resin prepolymer prior to curing the phenolic resin prepolymer so as to synthesise the phenolic resin. 3. A material as claimed in claim 2 wherein the phenolic resin prepolymer is a novolak resin. 4. A material as claimed in claim 2 wherein the phenolic resin prepolymer is a resole resin. 5. A material as claimed in any one of claims 2 to 4 wherein the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 10 to 90 wt%, one or more fillers in an amount of from 5 to 60 wt% and one or more minerals in an amount of from 5 to 60 wt% based on the total weight of the mixture. 6. A material as claimed in any one of claims 2 to 4 wherein the mixture prior to curing comprises phenolic resin prepolymer in an amount of from 40 comprises silica in an amount of from 20 to 80 wt%, alumina in an amount of from 5 to 30 wt%, magnesia in an amount of from 0.05 to 30 wt% and ferric oxide in an amount of from 0.05 to 10 wt%, based on the total weight of the mineral. 18. A material as claimed in any one of claims 1 to 17 wherein the mineral is expanded perlite. 19. A material as claimed in any one of claims 1 to 17 wherein the mineral is expanded vermiculite. 20. Use of a material as claimed in any one of claims 1 to 19 as a fire retardant material. 21. A process for forming a thermal insulation material comprising mixing a phenolic resin prepolymer with one or more fillers selected from the group consisting of alkaline earth metal sulphates and alkaline earth metal oxides and with one or more minerals selected from the group consisting of mica, igneous rock and minerals derivable from igneous rock and curing the mixture to convert the phenolic resin prepolymer into a phenolic resin. sufficient to bind components (i) and (ii).
12. A material as claimed in claim 11 which comprises a cured phenolic resin in an amount of from 10 to 90 wt %, one or more fillers in an amount of from 5 to 60 wt% and one or more minerals in an amount of from 5 to 60 wt %, based on the total weight of the resin.
13. A material as claimed in claim 11 which comprises a cured phenolic resin in an amount of from 40 to 80 wt %, one or more fillers in an amount of from 10 to 30 wt% and one or more minerals in an amount of from 10 to 30 wt%, based on the total weight of the resin.
14. A material as claimed in claim 11 which comprises a cured phenolic resin in an amount of from 60 to 70 wt %, one or more fillers in an amount of from 15 to 20 wt% and one or more minerals in an amount of from 15 to 20 wt %, based on the total weight of the resin.
15. A material as claimed in any one of claims 11 to 14 which further comprises one or more materials selected from the group consisting of glass fibre, carbon fibre and metal particles.
16. A material as claimed in any one of claims 1 to 15 wherein the one or more fillers are selected from the group consisting of hydrated calcium sulphate, calcium sulphate hemihydrate, anhydrous calcium sulphate and calcium oxide.
17. A material as claimed in any one of claims 1 to 16 wherein the mineral is igneous rock or a mineral derivable from igneous rock which