GB2204045A - Epoxy resin composition - Google Patents

Description

3-16504/+/CGJ 28 Epoxy resin composition The present invention relates to

an epoxy resin composition containing an inorganic filler, an anionic surfactant and a silane coupler.

Epoxy resin compositions into which one or more inorganic fillers such as quartz powder, alumina, talcum, calcium carbonate or the like are in corporated, are used in particular in the fields of casting, moulding and impregnation, and also as modified epoxy resin compositions, for example as adhesive or coating material, and as compositions for use in struc tural engineering and in the building sector. These epoxy resin com positions which contain inorganic fillers have the disadvantage that, on transportation or-in the course of storage, the inorganic filler is apt to precipitate or solidify.

The combined use of thixotropic agents such as very finely ground quartz powder (commercially available under the registered trademark Aerosila), bentonite and the like, is a known means of preventing i-his phenomenon.

However, the addition of quartz powder and the like is disadvantageous in that it increases the viscosity of the epoxy resin composition, thereby making it less easy to process the composition and reducing its productivity.

Accordingly, with regard to epoxy resin compositions which contain inorganic fillers, a solution is sought to the problem of preventing the solidification of the inorganic filler without the addition of material that increases the viscosity of the compositions, for example quartz powder, bentonite and the like.

One possibility is to add a surfactant which imparts to the epoxy resin a surface-active effect that enhances the wettability of the inorganic filler by said epoxy resin and thereby the dispersibility of the 2204045 2 - inorganic filler and so prevents solidification of the filler. The addition of the surfactant, however, causes marked deterioration of the defoaming and the antifoaming properties of the composition. A cured moulded article fabricated from such a composition therefore has an increased foam content and becomes fagile.

This method is therefore not used in actual practice.

It is therefore the object of the present invention to provide an epoxy resin composition in which the solidification of the inorganic filler is prevented by addition of a surfactant without causing any deterioration of the defoaming properties of the resin.

The use of cationic surfactants and silane couplers for solidifying loose underground sand formations in boreholes by means of curable organic resins is disclosed in German Offenlegungsschrift 2 652 045. Further, a process for the scratch-proof and abrasion-proof coating of glass containers with resin mixtures containing, inter alia, surfactants and silane couplers is disclosed in European patentapplication 57 595.

Non-ionic surfactants and silane couplers,as.constituents of aqueous primer compositions for glass fibres are disclosed in European patent application 83 053. A similar process, but using cationic surfactants, is disclosed in Japanese Kokai Sho 51-35 799. Non-tarnishing, abrasion-proof coatings for transparent polycarbonate mouldings which contain, inter alia, an epoxidised silane coupler as well as a non-ionic surfactant in an acrylate polymer composition are disclosed in US patent specifi cation 4 522 966.

Surprisingly, it has now been found that the defoaming and antifoaming properties can be improved and, in addition, the solidification of the inorganic filler prevented, jy adding a silane coupler to an epoxy resin composition that contains a surfactant.

Accordingly, the present invention relates to an epoxy resin composition which contains an inorganic filler, an anionic surfactant and a silane coupler.

3 The epoxy resin composition of this invention conveniently contains 5-700 parts by weight of an inorganic filler, 0.01-5.0 parts by weight, preferably 0.05-1.0 part by weight, of an anionic surfactant, and 0.001-10.0 parts by weight, prqferably 0.01-1.0 part by weight, of a silane coupler, based on 100 parts by weight of the epoxy resin.

The amount of anionic surfactant can also depend on the amount of the inorganic filler. However, if the amount of anionic surfactant in the composition is less than 0.01 part by weight, based on 100 parts by weight of epoxy resin, then it has no effect. If the amount of anionic surfactant is greater than 5.0 parts by weight, then the defoaming property of the composition is substantially reduced, so that the silane coupler can no longer exert its protective action. Therefore the appropriate amount of anionic surfactant is from 0.01-5.0 parts by weight. If the amount of anionic surfactant in the composition is less than 0.05 part by weight, then it has virtually no effect, although the solidification of the inorganic filler is minimally prevented. If the amount of anionic surfactant is 1.0-5.0 parts by weight, then the defoaming and antifoaming properties are so severely impaired that the silane coupler has no effect or has to be added in a large amount to produce an effect, so that the glass transition temperature of the cured product is lowered and th cost of the resin composition rises to an uneconomic level. The preferred amount of anionic surfactant is therefore from 0.05-1.0 part by weight.

The amount of silane coupler can depend on the amount of the anionic surfactant. But if the amount of silane coupler is less than 0.001 part by weight, based on 100 parts by weight of epoxy resin, then the coupler has no effect. If the amount exceeds 10.0 parts by weight, such a large amount of silane coupler lokyers the glass transition temperature (Tg value). The silane coupler should therefore suitably be used in an amount of 0.001-10.0 parts by weight. If the amount of silane coupler is less than 0.01 part by weigh, then the defoaming process takes too long and the resin composition becomes less easy to process, although a certain enhancement of the defoaming and antifoaming properties is attained. If the amount of silane coupler is from 1.0-10.0 parts by weight, this large amount lowers the glass transition temperature and the heat resistance of 4 the cured product and, in addition, increases the cost of the compo sition, so that the use of such a large amount of silane coupler is no longer of practical interest. The preferred amount of silane coupler is therefore 0.01-1.0 part by weight.

Epoxy resins suitable for use in this invention are all polyepoxides which contain, on average, two or more 1,2-epoxy groups in the molecule.

These epoxides can be saturated, unsaturated, aliphatic, alicyclic, aromatic or heterocyclic epoxides. They may also contain a non-hindering substituent such as a halogen atom, a hydroxyl group, an ether group, an ester group or the like. Examples of such polyepoxides are novolaks, polyglycidyl ethers of dihydric phenols such as 2,2-bis(4-hydroxyphenyl) propane, 1,1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane, bis(4-hydroxyphenyl)sulfone, resorcinol or hydroquinone; polyglycidyl ethers of trihydric alcohols, for example glycerol; polyglycidyl esters such as diglycidyl phthalate or diglycidyl isophthalate; epoxidised esters of polyethylenically unsaturated fatty acids such as epoxidised linseed oil; epoxidised esters of unsaturated alcohols with unsaturated carboxylic acids, for example 3,4-epoxycyclohexylmethyl-1,3,4-epoxycyclohexylcarboxylate; and epoxidised polyethylenically unsaturated hydrocarbons such as epoxidised 2,2-bis(2-cyclohexenyl)propane, epoxidised vinyl cyclohexane, epoxidised cyclopentadiene dimer and ^::be like.

Preferred epoxy resins are polyglycidyl ethers of polyhydric phenols and epoxide esters of unsaturated alcohols with unsaturated carboxlic acids.

Surfactants comprise cationic, non-ionic and anionic surfactants as well as those of the block copolymer type. Not even the addition of a silane coupler is able to improve the defoaming properties of cationic, non-ionic or block copolymer surfactants. Only the defoaming propertien of anionic surfactants are improved by the addition of a silane coupler.

Accordingly, the present invention relates to the use of anionic surfactants.

Anionic surfactants comprise carboxylates, sulfonates, e.g. alky.1 benzenesulfonates, alky1naphthalenesulfonates, alkylsulfonates, a-alefinsulfonates, a-sulfo fatty acid esters, sulfosuccinates; alkoxy sulfonates, acyloxysulfonates Qr acylaminoalkanesulfonates, sulfates such as alkylsulfates or ether sulfates, phosphonates or phosphates.

Anionic surfactants which are especially eligible for use in this invention are ether sulfates, for example sodium polyoxyethylene lauryl ether sulfate, triethanolamine polyoxyethylene lauryl ether sulfate, sodium polyoxyethylene alkyl ether sulfate, sodium alkyl sulfate, triethanolamine alkyl sulfate, which are particularly preferred.

Silane couplers comprise organoepoxysilanes, organoaminosilanes, arganocarboxysilanes, organomercaptosilanes, organomethacryloxy6iianei', organochlorosilanes, organovinylsilanes and organocyanosilanes.

Examples of particularly suitable silane couplers are the organo epoxysilanes, such as:

glycidoxymethyltrimethoxysilane -glycidoxymethyltriethoxysilane 0-glycidoxyethyltrimethoxysilane 0-glycidoxyethyltriethoxysilane y-glycidoxypropyltrimethoxysilane 7-glycidoxypropyltriethoxysilane y-glycidoxypropyltri(methoxyethoxy)silane y-glycidoxypropyltriacetaxysilane 6-glycidoxybutyltrimetboxysilane 6-glyc-idoxybutyltriethoxysilane glycidoxymethyldimethoxysilane glycidoxymethyl(methyl)dimethoxysilane glycidoxymethyl(ethyl)dimethoxysilane glycidoxvMethyl(phenyl)dimethoxysilane glycidoxymethyl(vinyl)dimetboxysilane glycidoxymethyl(dimethyl)methoxysilane B-glycidoxyethyl(methyl)dimethoxysilane B-glycidoxyethyl(ethyl)dimethoxysilane 0-glycidoxyethyl(dimethyl)methoxysilane 6 y-glycidoxypropyl(methylldimethoxysilane Y-glycidoxypropyl(ethyl)dimethoxysilane y-glycidoxypropyl(dimethyl)methoxysilane d-glycidoxybutyl(methyl)dimethoxysilane 6-glycidoxybutyl(e.thyl)dimethoxysilane 6-glycidoxybutyl(dimethyl)methoxysilane bis(glycidoxymethyl)dimethoxysilane bis(glycidoxymethyl)diethoxysilane bis(glycidoxyethyl)dimethoxysilane bis(glycidoxyethyl)diethoxysilane bis(glycidoxypropyl)dimethoxysilane bis(glycidoxypropyl)diethoxysilane tris(glycidoxymethyl)methoxysilane tris(glycidoxymethyl)ethoxysilane 4.

tris(glycidoxyethyl)methoxysilane tris(glycidoxyethyl)ethoxysilane tris(glycidoxypropyl)methpxysilane tris(glycidoxypropyl)ethoxysilane glycidylmethyltrimethoxysilane glycidylmethyltriethoxysilane 0-glycidylethyltrimethoxysilane 0-glycidylethyltriethoxysilane y-glycidylpropyltrimethoxysilane y-glycidylpropyltriethoxysilane y-glycidylpropyltri(methoxyethoxy)silane y-glycidylpropyltriacetoxysilane 3,4-epoxycyclohexylmethyltrimethoxysilane 3,4-epoxycyclohexylmethyltriethoxysilane 3,4-epoxycyclohexylethyltrimethoxysilane 3,4-epoxycyclohexylpropyltrimethoxysilane 3,4-epoxycyclohexylbutyltrimethoxysilane.

y-Glycidoxypropyltrimethoxysilane and a-(3,4-epoxycyclohexyl)ethyltrimethoxysilane are especially preferred.

7 The presence of a surfactant in the epoxy resin composition of this invention effects enhanced dispersibilifty of the inorganic filler and prevents the solidification and sedimentation thereof. As the composition additionally contains a silane coupler, the deterioration of the defoaming properties of the surfactant is prevented.

Thus neither solidification nor sedimentation of the inorganic filler in the composition of this invention occurs and the composition has excellent defoaming properties, so that cured products of high quality can be obtained by using such epoxy resin compositions.

The epoxy resin compositions of this invention can also contain further components which have no influence on the effect obtained. Examples of such additional components are dyes and stabilisers.

The invention is illustrated in more detail by the following Examples.

Example 1: A resin composition is prepared by compounding 100 parts by weight of a liquid bisphenol A type epoxy resin having a epoxy equivalent of 189 (Araldite GY 260, available from CIBA-GEIGY AG.) with 0.10 part by weight of triethanolamine polyoxyethylene lauryl ether sulfate, 0.02 part by weight of 7-glycidoxypropyltrimethoxysilane and 50 parts by weight of crystalline silica powder (available unter the registered trademark 3H from Nagase & Co., Japan).

Example 2: A resin composition is prepared by compounding 100 parts by weight of a liquid bisphenol F type epoxy resin (Epiclon 830-S, available from DIC Co., Japan) with 0.10 part by weight of triethanolamine poly oxyethylene lauryl ether sulfate, 0.02 part by weight of y-glycidoxy propyltrimethoxysilane and 50 parts by weight of crystalline silica powder (as in Example 1).

Comparative.Example 1: A resin composition is prepared by compounding parts by weight of a liquid bisphenol A type epoxy resin (AralditeO GY 260, CIBA-GEIGY AG) with 50 parts by weight of silica powder (as in Example 1).

8 Comparative Example 2: A resin composition is prepared by compounding parts by weight of a liquid bisphenol F type epoxy resin (Epiclon 830-S, DIC Co., Japan) with 50 parts by weight of silica powder (as in Example 1).

Use Example 1: 300 g of each of the epoxy resin compositions of Ex ample 1, Example 2, Comparative Example 1 and Comparative Example 2 are introduced into a 300 ml bottle and subjected to a 12 day (ca. 6000 km) transportation test by truck, and subsequently examined for the degree of solidification. The results are reported in Table 1.

Table 1

Example 1 Example 2 Comparative Comparative Example 1 Example 2 degree of 0 0 X X solidification In Table 1 and the following tables, the symbols 0, A and X denote the following degrees of solidification:

0: If a rod is thrust into a samplg and pushed with the finger, the rod reaches the bottom easily.

A: If a rod is thrust into a sample and pushed forcibly, the rod reaches the bottom.

X: The.7od cannot be thrust into the sample at all.

In the epoxy resin compositions of Examples 1 and 2 of the present invention, the silica powder does not solidify and can be readily stirred even if sedimentation takes place. The epoxy resin compositions of Comparative Examples 1 and 2 do not contain the anionic surfactant or the silane coupler. In both compositions the silica solidifies.

Use Example 2: Each of the epoxy resin compositions of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 is filled into a test tube (30 cm x 200 mm) to a height of 180 mm and the test tube is vertically placed in a hot Air circulation oven and subjected to a heat ageing test for 24 hours at 80C and for 8 hours at 120C. In this test, the content of the test tube separates into a clear layer A, a filler dispersion layer B and layer C of excess filler. The heights of the layers (layer A: a mm; layer B: b mm, layer C: c mm) are measured, and the degree of sedimentation is calculated according to the following equation. A greater degree of sedimentation means that the filler is more uniformly dispersed in the resin and the degree of solidification is smaller.

Degree of sedimentation = c - X 100 [%] a + b + c In addition, the degree of solidification is evaluated in accordance with Use Example 1. The results are as shown in Table 2.

Table 2

Example ExamplelComparative Comparative 1 2 iExample 1 Example 2 Degree of sedi- 80'C/24 h 33 36 27 27 mentation 120'C/8 h 40 45 32 32 Degree of 0 0 X X solidification The results shown in Table 2 demonstrate that the epoxy resin compo sitions of Examples 1 and 2 are free from solidification of silica in the heat ageing test and that, even if sedimentation does take place, the precipitated silica layer can be easily stirred. On the other hand, the epoxy resin compositions of Comparative Examples 1 and 2 exhibit marked sedimentation and solidification of the inorganic filler as compared with the compositions of Examples 1 and 2.

Use Example 3: Epoxy resin compositions having the same formulation as in Example 1, except that no silane coupler is used and the amount of anionic surfactant is varied, are prepared. These compositions are subjected to the same heat ageing test of 80'Cl24 hours as in Use Example 2. The amount of anionic surfactant in these compositions and the results of the test are summarised in Table 3.

Table 3

Formulation: AralditeO GY 260 100 100 100 100 100 100 100 1) [parts by 0.05 0.1 0.2 0.5 1.0 2.0 Surfactant weight] Silica powder so so so so 50 so so 2) 0 X X X XX XXX XXX defoaming properties degree of sedimentation 27 32 33 31 29 27 27 1) Triethanolamine polyoxyethylene lauryl ether sulfate 2) Defoaming properties 0: Usual defoaming and antifoaming properties are exhibited (standard).

A: The foam disappears under reduced pressure over a substantial period of time, and the time taken for defoaming is longer than in 0.

X: Even under reduced pressure, the time taken until the dis- appearance of the foam is longer than in 0, and complete defoaming cannot be attained.

XX: Defoaming takes even longer than in X, and complete defoaming cannot be achieved even after a substantial period of time under reduced pressure.

XXX: No defoaming is achieved after even a longer period of time than in XX under reduced pressure.

It is apparent from Table 3 that, when no silane coupler is used, the addition of an anionic surfactant causes the defoaming properties of the composition to deteriorate. The defoaming properties deteriorate with increasing amounts of anionic s.urfactant, and no defoaming takes place at all when the amount of anionic surfactant is greater than 0.5 part by weight. As regards the degree of sedimentation, good results are achieved with all the compositions.

Use Example 4: Epoxy resin compostions having the same formulation as in Example 1 are prepared, except that the amount of silane coupler is varied. These compositions are subjected to the heat ageing test of WC/24 hours in the same manner as in Use Example 2. The amount of silane coupler in the compositions and the results of the test are summarised in Table 4.

Table 4

Formulation: AralditeO GY 260 100 100 100 100 100 100 100 [parts by surfactant 1) 0.1 0.1 0.1 0.1 0.1 0.1 - weight 1 silica powder 50 so 50 so 50 50 50 silane coupler 3) 0.002 0.00 6 0.015 0.02 0.05 0.1 0.02 defoaming properties 2) A A A-0 0 0 0 0 degree of sedimentation 33 33 33 33 34 34 27 1) + 2) see Table 3 3) 7-Glycidoxypropyltrimethoxysilane The results shown in Table 4 demonstrate that the silane coupler exhibits its effect when used in an amount of 0.015 part by weight. Although the results obtained with all the compositions are good with respect to the degree of sedimentation regardless of the amount of silane coupler, only the composition containing no surfacant and containing silane coupler exhibits a low degree of sedimentation, demonstrating that it is in a sclid state.

12 Use Example 5: Epoxy resi;i compositions are prepared in accordance with Example 1, except that the anionic surfactant is replaced by a cationic, nonionic or block copolymer type surfactant and the amount of silane coupler is varied. These compos.itions are tested for their defoaming properties, degree of sedimentation and degree of solidification in accordance with the procedures described in Use Examples 1 to 3, except that the degree of sedimentation is tested only after heat ageing for 24 hours at 80'C. The results are reported in Table 5.

Table 5

Formulation: Aralditec GY 260 100 100 100 100 100 100 [parts by surfactant cationic 1) 0.1 weight] 2) 0.1 nonionic block 3) 0.1 0.1 0.1 0.1 copo ymer silica powder so so so so so 50 4) 0.02 0.05 0.10 silane coupler 5) X X- X X X X defoaming properties degree of sedimentation 29 29 32 32 34 35 degree of solidification 6) X X 0 G 0 0 1) Cetyltrimethylammonium chloride, stearylbenzyldimethylammonium chloride or the like.

2) Polyoxyethylene nonylphenyl ether or the like.

3) Ethylene oxide-propylene oxide block copolymer.

4) y-glycidoxypropyltrimethoxysilane 5) see Table 3 6) see Table 1 The results of this test demonstrate that, if a cationic or nonionic surfactant is used as the surfactant, the defoaming properties and the degree of solidification are not improved. If a block copolymer sur- 13 factant is used, the defoaming properties are not improved even by the addition of a silane coupler. However, the degree of solidification and the degree of sedimentation are improved.

In the epoxy resins compositions of the present invention, hardly any precipitation and solidification of the inorganic filler occurs in the course of transportation or storage at elevated temperature. Even if precipitation or solidification does occur, disintegration can be readily effected by simple stirring. Further, there is no increase in the viscosity of the epoxy resin composition or in the foaming propensity which makes cured products made therefrom fragile. Accordingly, the epoxy resin composition of the present invention can be easily processed and has good productivitiy and gives a cured product of high quality when used as a casting or moulding r esin.

- 14

Claims (12)

1. t is claimed is:

   I. An epoxy resin composition containing an inorganic filler, an anionic surfactant and a silane coupler.
2. 2. A composition according to claim I, which contains 5-700 parts by weight of inorganic filler, based on 100 parts by weight of epoxy resin.
3. 3. A composition according to claim 1 or 2, which contains 0.01-5.0 parts by weight of anionic surfactant, based on 100 parts of epoxy resin.
4. 4. A composition according to claim 3, which contains 0.05-1.0 part by weight of anionic surfactant.
5. 5. A composition according to any preceding claim, which contains 0.00110.0 parts by weight of silane coupler, based on 100 parts by weight of epoxy resin.
6. 6. A composition according to claim 5, which contains 0.01-1.0 part by weight of silane coupler.
7. 7. A composition according to any preceding claim, wherein the epoxy resin is a polyepoxide containing an averge of two or more 1,2-epoxy groups in the molecule.
8. 8. A composition according to any preceding claim, wherein the anionic surfactant is a carboxylate, a sulfonate, a sulfate, a phosphonate or a phosphate.
9. 9. A composition according to claim 8, wherein the anionic surfactant is an ether sulfate.
10. 10. A composition according to any preceding claim, wherein the silane coupler is an organoepoxysilane, an organoaminosilane, an organocarboxy silane, an organomercaptosilane, an organomethacryloxysilane, an organochlornsilane, an organovinylsilane or an organocyanosilane.
11. Ii. A composition according to claim 10, wherein the silane coupler is an organoepoxysilane.
12. 12. A composition according to claim I substantially as hereinbefore described with reference to any of the foregoing Examples.

    Published 1988 a, The Patent Offi-ce, State I-louse. 6671 High Holborn, London WC1R 4TP. Further copies may, be obtained from The Patent Office.

    Salle-s Branch. St Mary Cray. Orpington. Kent BR5 3RD. Printed by Multiplex techniques ltd, St Mary Cray, Kent. Con. 1/87.