NO162666B - PROCEDURE FOR THE MANUFACTURING OF RESPECTABLE MATERIALS. - Google Patents

Description

The present invention relates to a method for the production of resinous materials which can be diluted with water.

In order to achieve a corrosion-resistant coating on metal containers, it is common to coat the metal surface with a crosslinkable resin composition dissolved in an organic solvent, and then heat the coating to evaporate the solvent and crosslink the resin. Cross-linking of the coating transforms it into a strong, adherent, flexible and protective film. During the heating, the solvent is usually evaporated to the atmosphere. Since organic solvents are relatively expensive, easily flammable and usually harmful to the environment, there is a need for coatings that can be applied using minimal amounts of such solvents, particularly useful are coating compositions that contain a large proportion of water.

US Patent No. 4,362,853 describes resin salts prepared from a phenol-terminated resin by a Mannich reaction with an amino acid and an aldehyde, with complete or partial neutralization of the carboxylic acid group or groups introduced at the amino acid.

In West German Explanatory Document No. 3,247,281, the resin salt prepared from a phenol-terminated resin is described, either by thioalkylation with a mercaptocarboxylic acid and an aldehyde followed by at least partial neutralization of the carboxylic acid group(s) introduced by the mercaptocarboxylic acid, or by sulfoalkylation ■ with sulfuric acid (or a water-soluble salt thereof) and an aldehyde, if necessary followed by at least partial neutralization of the sulfonic acid group(s) introduced by the sulfuric acid or its salt.

Other resin salts are described in British Patent No. 2,118,936 A. These salts are prepared from a phenol-terminated resin by a Mannich reaction with an aldehyde or an aminophosphonic acid or an aminosulfonic acid followed by complete or partial neutralization of the acid group(é) introduced by this reaction.

Each of the above-mentioned patents describes the use of resin salts, either alone or together with an aminoplast, a phenoplast or a block-formed polyisocyanate, in aqueous compositions for surface coatings.

US patent no. 4,308,185 describes a method where an epoxy resin is reacted with an addition polymerizable monomer so that a grafted polymer is formed. For the production of a water-dispersible product, a carboxyl-functional monomer is used; in order to limit the reaction of the epoxy groups in the resin with the carboxyl groups in the monomer, the resin is reacted with a terminating agent, which may be bisphenol A, to remove some or all of the epoxy groups.

It has now been found that the properties of resinous reaction products of a phenol-terminated resin, an aldehyde and an acid (or salt), such as those described above, can be improved by a modification involving polymerization of a vinyl monomer in the phenolic terminated the resin, or a precursor thereof, prior to reaction with the aldehyde and the acid (or salt). In particular, aqueous coating compositions having a higher viscosity for a given solids content can be obtained if the modified products are included, and coatings having improved acid resistance can be obtained. There is no indication in the above-mentioned patent documents that such a modification would produce an advantageous result.

Accordingly, the present invention provides a process for the production of resin materials that can be diluted with water which includes reacting the following components: (A) a resin having at least one phenolic hydroxyl group and a free position in the ortho and/or para position to

the phenolic hydroxyl group, med

(B) an aldehyde, and

(C) a sulfuric acid or an organic acid containing

a primary or secondary amino group or a

mercaptan group and a carboxylic acid, sulphonic acid or phosphonic acid group, or a water-soluble salt thereof.

The method is characterized by the fact that the resin (A) contains a residue formed by polymerization of a vihyl monomer in the resin, or a precursor thereof.

The resin (A) generally has from 1 to 4 phenolic hydroxyl groups, resins which on average have between 1 and 2 phenolic hydroxyl groups per molecule is preferred. Preferably, the resin has a backbone derived from an epoxy resin or phenoxy resin. The molecular weight of the resin is usually from 1,000 to 10,000, preferably from 2,000 to 4,000.

Suitable resins (A) are those obtained by reacting an epoxy resin with a polyhydric phenol having a free position ortho and/or para to a phenolic hydroxyl group, so that a phenol-terminated resin is formed and then polymerizing a vinyl monomer in the latter. Known methods can be used to react the epoxy resin with the polyhydric phenol. Preferably, the epoxy resin is a diepoxide and the polyhydric phenol is a dihydric phenol; there must be at least as much divalent phenol present, on a molar basis, as there is diepoxide to give a product having at least one terminal phenolic hydroxyl group. The molar ratio of diepoxide to dihydric phenol is usually in the range of 1:1.02 to 1:1.6, especially 1:1.1 to 1:1.5. The preferred method for carrying out the reaction is to heat the reactants to 100-200°C in the presence of a base, which may be a tertiary amine, but which is preferably an alkali metal hydroxide. The reaction can be carried out in an inert solvent.

The divalent phenol used in the reaction with the epoxy resin can be a mononuclear phenol such as e.g. hydroquinone or resorcinol but is preferably a bisphenol, which may be substituted, especially a compound of the formula:

where each R<1>, which may be the same or different, represents a hydrogen atom, a halogen atom, an alkyl group of 1 to 4 carbon atoms, or an alkenyl group of 2 to 4 carbon atoms, provided that at least 1 of R<1 >the groups ortho to a phenolic hydroxyl group are a hydrogen atom, and

X represents an alkylene or alkylidene group of 1 to 3 carbon atoms, a carbonyl or sulfonyl group, an oxygen or sulfur atom, or a valence bond.

Examples of particularly preferred bisphenols are bis(4-hydroxyphenyl)methane and 2,2-bis(4-hydroxyphenyl)propane. Epoxy resins (polyepoxides) which are preferred for reaction with the divalent phenol are those which contain two terminal glycidyl groups directly linked to an atom, or atoms, of oxygen, nitrogen, or sulfur.

Examples of such resins include polyglycidyl esters which can be obtained by reaction between a compound containing 2 carboxylic acid groups per molecule and epichlorohydrin or glycerol dichlorohydrin in the presence of alkali. Such polyglycidyl esters can be derived from aliphatic polycarboxylic acids, e.g. oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and dimerized linoleic acid; from cycloaliphatic polycarboxylic acids such as e.g. tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid, and 4-methyl-hexahydrophthalic acid; and from aromatic polycarboxylic acids, such as e.g. phthalic acid, isophthalic acid, and terephthalic acid.

Further examples are polyglycidyl ethers which can be obtained by reaction between a compound containing at least two free alcoholic hydroxyl or phenolic hydroxyl groups per molecule and epichlorohydrin or glycerol dichlorohydrin under alkaline conditions, or alternatively in the presence of an acid catalyst with subsequent treatment with alkali. These ethers can be prepared from acyclic alcohols such as e.g. ethylene glycol, diethylene glycol, and higher poly(oxyethylene) glycols, propane-1,2-diol and poly(oxypropylene) glycols, propane-1,3-diol, butane-1,4-diol, poly(oxytetramethylene) glycols, pentane- 1,5-diol, and polyepichlorohydrins from cycloaliphatic alcohols such as e.g. resorsitol, quinintole, bis(4-hydroxycyclohexyl)methane, 2,2-bis(4-hydroxycyclohexyl)propane, and 1,1-bis(hydroxymethyl)cyclohex-3-ene; and from alcohols that have an aromatic core, such as e.g. N,N-bis(2-hydroxyethyl)-aniline and p,p'-bis(2-hydroxyethylamino)diphenylmethane. Or they can be prepared from mononuclear phenols, such as e.g. resorcinol and hydroquinone, and from polynuclear phenols, such as e.g. bis(4-hydroxyphenyl)methane, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl) sulfone, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxy -phenyl)propane. and 2,2-bis(2-allyl-4-hydroxyphenyl)propane.

Poly(N-glycidyl) compounds include, for example, those formed by hydrochlorination of the reaction products between epichlorohydrin and amines containing two amino hydrogen atoms such as aniline, n-butylamine, and bis(4-methylaminophenyl)methane; and N,N'-diglysidyl derivatives of cyclic alkylene urea compounds, such as e.g. ethylene urea and 1,3-propylene urea, and of hydantoins such as e.g. 5,5-dimethylhydantoin.

Examples of poly(S-glycidyl) compounds are di-S-glycidyl derivatives of dithiols such as e.g. ethane-1,2-dithiol and bis(4-mercaptomethylphenyl) ether.

Polyepoxides having the 1,2-epoxy groups connected to different types of heteroatoms can be used, e.g. the glycidyl ether glycidyl ester of salicylic acid, N-glycidyl-N'-(2-glycidyloxypropyl)-5,5-dimethylhydantoin, and 2-glycidyloxy-1,3-bis(5,5-dimethyl-1-glycidylhydantoin-3- yl) propane.

Polyepoxides containing non-terminal epoxy groups can also be used, such as e.g. vinylcyclohexene dioxide, limonene dioxide, dicyclopentadiene oxide, 4-oxatetracyclo [6, 2,1, 02' 7 ,03, 5] -undec-9-yl glycidyl ether, bis (4-oxatetracyclo [6, 2,1,02'7,03' 5 ] -undec-9-yl) ether of ethylene glycol, 3, 4-epoxycyclohexylmethyl 3',4'-epoxycyclohexanecarboxylate and its 6,6'-dimethyl derivative, bis(3,4-epoxycyclohexanecarboxylate) of ethylene glycol, and 3 -(3,4-epoxycyclohexyl)-8,9-epoxy-2,4-dioxaspiro [5,5]undecane. If desired, a mixture of diepoxides can also be used. Polyepoxides containing more than two epoxy groups can be used, but the reaction between such polyepoxides and polyfunctional reactants is more difficult, as there is a risk of gelation.

Preferred diepoxides are diglycidyl ethers and diglycidyl esters. Specific preferred diepoxides are diglycidyl ethers of 2,2-bis(4-hydroxyphenyl)propane or bis(4-hydroxyphenyl)methane, which have a 1,2-epoxy content of more than 1.0 equivalent per kilo.

The dihydric phenol can be used alone or, if desired, in the presence of a compound which reacts with an epoxy group in the polyepoxide, but which would not react further so that further chain-extending reactions are avoided. Suitable such "chain terminators" are secondary monoamines, monocarboxylic acids and, more particularly, monohydric phenols, p-tert-butylphenol being particularly preferred. If a chain terminator is added, it must be in such a quantity that at least one epoxy group per average molecule of the polyepoxide remains free, allowing it to react with the divalent phenol.

Other suitable resins (A) are those obtained by polymerizing a vinyl monomer in an epoxy resin having a secondary alcoholic hydroxyl group, and then reacting the resulting product with a polyhydric phenol having a free position ortho and/or para ti], a phenolic hydroxyl group to form a phenol-terminated resin. The reaction of the epoxy resin (containing in situ polymerized vinyl monomer) with the polyhydric phenol, which is preferably a dihydric phenol, can be carried out under similar conditions to the epoxy resin-polyhydric phenol reaction described above, using the same dihydric phenols and, if desired, chain terminators. The epoxy resin having a secondary alcoholic hydroxyl group may be a polygly.cAdyl ester, polyglycidyl ether, or poly(N-glycidyl) compound as described above derived from epichlorohydrin and an excess of the polycarboxylic acid, polyhydric alcohol or phenol, or nitrogen compound, respectively. Alternatively, it may be a resin obtained by developing any of the epoxy resins described above, preferably a resin having two terminal glycidyl groups, with a reactant having at least two groups which are reactive with the epoxy groups in relative amounts to produce an epoxy -terminated product. Suitable such promoting reactants include polyfunctional, preferably difunctional, alcohols, carboxylic acids, amines, mercaptans and, especially, phenols. Preferred divalent phenols are the phenols of formula I above. The conditions for the promotion reaction correspond to those described above for the preparation of a phenol-terminated reaction product of an epoxy resin and a dihydric phenol, except that the ratio of the number of chemical equivalents of promoting reactants to epoxy resin is usually in the range of 1:1.02 to 1 :1.6, especially 1:1.1 to 1:1.5.

Other suitable resins (A) are those obtained by polymerization of a vinyl monomer in a phenoxy resin, i.e. a phenol-terminated resin analogous to the resin produced by reaction between bisphenol diglycidyl ether and a bisphenol, but obtained directly by reaction between a bisphenol and epichlorohydrin. The phenoxy resin-forming reaction is usually carried out in an alkaline medium by using approximately equimolar amounts of bisphenol and epichlorohydrin, a chain terminator, which e.g. monovalent phenol is added when the desired molecular weight is reached.

As indicated above, the vinyl monomer can be polymerized in the phenol-terminated resin or in its e/t epoxy resin precursor. The monomer, together with a free radical polymerization initiator, can be mixed with the resin or with a solution of the resin in an organic solvent, such as e.g. n-butanol, 2-ethoxyethanol, 2-butoxyethanol, ethyl acetate, toluene, xylene or tetrahydrofuran. In situ polymerization can be effected by heating the mixture to a temperature of 60 to 200°C, preferably 100 to 150°C, usually for a period of from 1 to 10 hours. The monomer can be used in such an amount that it provides up to 50% by weight of the resin (A), i.e. the total weight of the phenol-terminated resin and the polymerized vinyl monomer. It is preferred to use quantities so that up to 40% by weight, in particular 10 to 30% by weight, of resin (A) is provided. That is, where the monomer is polymerized in the phenol-terminated resin it can be used in amounts up to 100% by weight of the resin, amounts up to 67% by weight, especially 11 to 43% by weight, are preferred. The free radical initiator is usually present in an amount of from 1 to 20% by weight, typically 2 to 10% by weight, of the monomer. The monomer and/or initiator can advantageously be added to the resin in two or more stages, where the mixture is heated for 1 to 3 hours after each addition.

Suitable vinyl monomers include styrenes, e.g. styrene itself, ring-substituted styrenes such as 4-methylstyrene and 4-bromostyrene, and α - and 3-substituted styrenes such as e.g. α-methylstyrene and 3-methylstyrene; acrylic acid, methacrylic acid and esters thereof, e.g. alkyl esters, especially those where the alkyl groups have from 1 to 6 carbon atoms such as e.g. ethyl acrylate and methyl methacrylate, and hydroxyalkyl esters, especially hydroxyethyl and hydroxypropyl esters; acrylamide, methacrylamide and hydroxyalkyl derivatives thereof such as e.g. N-methylolacrylamide; and vinyl esters of carboxylic acids such as e.g. vinyl acetate and vinyl propionate. Mixtures of two or more vinyl monomers can be used. Particularly preferred monomers are styrene, ethyl methacrylate and mixtures of these two compounds.

The free radical polymerization initiator can advantageously be a peroxide, which can be inorganic or organic. Examples of inorganic peroxides are hydrogen peroxide and persulphates, which e.g. potassium and sodium persulfates. Examples of organic peroxides are acyl peroxides such as benzoyl peroxide, p-chlorobenzoyl peroxide and t-butyl perbenzoate, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, and hydroperoxides such as e.g. cumene hydroperoxide and t-butyl hydroperoxide. Other suitable initiators include azo compounds such as azobis(isobutyronitrile) and azobis(α-methylbutyronitrile). Preferred initiators are benzoyl peroxide, cumene hydroperoxide and azobis(isobutyronitrile).

The aldehyde (B) which reacts with the resin (A) and the acid (or salt) (C) to form a water-dilutable product is preferably an aliphatic aldehyde, especially an aldehyde having from 1 to 6 carbon atoms, although aromatic aldehydes can also be used, especially those having from 7 to 12 carbon atoms. Formaldehyde, which can advantageously be formed in situ from paraformaldehyde, is a particularly preferred aldehyde.

Useful acids (C) include aminosulfonic and aminophosphonic acids. The amino group and the sulphonic or phosphonic acid group can be connected with aliphatic, aromatic or araliphatic residues. Suitable such acids include compounds of the formula:

where R stands for a hydrogen atom or an alkyl group with from 1 to 6 carbon atoms,

R stands for an aliphatic, aromatic or araliphatic di- or trivalent hydrocarbon group with from 1 to 10 carbon atoms which may contain a free sulfonic or phosphonic acid group, and

Y stands for the residue of a sulfonic or phosphonic acid group after removal of a hydrogen atom (ie -SO3- or

-P02H-).

Aminosulfonic acids of formula II include sulfanilic acid, taurine, orthoanilic acid, and 2-aminobenzene-1,4-disulfonic acid.

Aminophosphonic acids of formula II further include compounds of the formula:

where either R<4> stands for an alkyl group with from 1 to 4 carbon atoms, an aryl group with from 6 to 10 carbon atoms or a free phosphonic acid group of the formula -P(:0)(OH)2"

R stands for a hydrogen atom, an alkyl group with from 1 to 4 carbon atoms, or an aryl group with from 6 to 10 carbon atoms, and

R^ stands for a covalent bond or an alkylene group with from 1 to 4 carbon atoms, or

R 4. and R 6 together with the carbon atom to which they are connected form an aromatic ring and R^ is absent.

Specific aminophosphonic acids of formula III include 2-amino-1-phenylethylphosphonic acid, 1-aminoethylidenebis(phosphonic acid) and aminophenylmethylenebis(phosphonic acid).

Other useful acids (C) are mercaptocarboxylic acids. In these acids, mercaptan and carboxylic acid groups can be connected with aliphatic, aromatic or araliphatic residues. Suitable mercaptocarboxylic acids include acids of the formula:

where R stands for an aliphatic, aromatic or araliphatic divalent group with 1 to 10 carbon atoms which may contain a further carboxylic acid group.

Specific acids of formula IV are thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid and thiomalic acid.

Other useful acids (C) are aminocarboxylic acids. The amino and carboxylic acid groups can be connected with aliphatic, aromatic or araliphatic residues. Suitable aminocarboxylic acids include acids of the formula:

where R^ stands for an aliphatic, aromatic or araliphatic divalent group with from 1 to 10 carbon atoms which may contain a further carboxylic acid group and which is preferably an alkylene group with from 1 to 4 carbon atoms or a phenylene group, and

R Q stands for a hydrogen atom, a group of the formula:

or an alkyl group with from 1 to 6 carbon atoms which may be substituted by a further carboxyl group or by a group of the formula -CH(R10)OH or -CH(R10)0R12, provided that R and R together do not contain more than one carboxylic acid group,

R'<1>"<0> stands for a hydrogen atom, an alkyl group with from 1 to 4 carbon atoms, or an aryl group with from 6 to 1C carbon atoms,

R^ stands for a hydrogen atom, a carboxylic acid group, or an alkyl group with from 1 to 6 carbon atoms which may be substituted with a carboxylic acid group or with a group of the formula -CH(R<10>)OH or CH(R10)OR12, and R stands for an alkyl group with from 1 to 6 carbon atoms or an alkoxyalkyl group where the alkoxy group and the alkyl group each have from 1 to 6 carbon atoms.

Specific acids of formula V which may be used include sarcosine, iminodiacetic acid, anthranilic acid, glycine, glutamic acid, aspartic acid and p-aminobenzoic acid.

Salt that can be used as component (C) in the method according to the invention includes the potassium and sodium salts of styrene described above and of sulfuric acid.

Preferably, component (C) is an aminocarboxylic acid or a mercaptocarboxylic acid, specific particularly preferred acids being glycine, glutamic acid, aspartic acid, p-aminobenzoic acid, sarcosine and thioglycolic acid.

The reaction between the resin (A), the aldehyde (B) and the acid or salt (C) can be effected by heating the reactants, usually in an inert solvent, preferably in the presence of sufficient base to at least partially neutralize any free acid. The reaction temperature is usually in the range from 60 to 180°C, especially 75 to 140°C, and the reaction is usually completed within a period of from 15 min. to 8 hours.

If necessary, a base, or additional base, may be added to the reaction product to improve its ability to be diluted with water. In general, at least 25% of the acid groups present in the reaction product are neutralized to obtain a product that can be fully diluted with water, although the extent of neutralization may vary with the properties of the reactant (C).

Suitable inert solvents include hydrocarbons, ethers, alcohols, and esters; among these, toluene, xylene, tetrahydrofuran, ethyl acetate, and especially 2-butoxyethanol and n-butanol, are preferred. Suitable bases for the partial neutralization include sodium hydroxide, sodium carbonate, potassium hydroxide, potassium carbonate, ammonia, triethylamine, and triethanolamine; 2-(dimethylamino)-2-methylpropan-1-ol and 2-(dimethylamino)ethanol are particularly preferred.

Usually 0.3 to 2.0 mol of the acid or salt is used

(C) per moles of phenolic hydroxyl groups in the resin (A). An excess of the aldehyde (B) is usually used, in particular

1.1 to 4.0 mol aldehyde per mol (C), because the products then show improved stability when stored at room temperature. If the resin (A) has more than one free ortho position

<

or para to a phenolic hydroxyl group, the application of an excess of an aliphatic aldehyde usually leads to a product having a hydroxyalkyl group attached to the f change, as a result of a reaction between the phenol-terminated resin and the excess of aldehyde, as it finds place in the formation of phenol-aldehyde resols under basic conditions; where the aldehyde is formaldehyde, the hydroxyalkyl group is naturally a methylol group.

The resinous materials produced according to the invention, i.e. the reaction products from (A), (B) and (C) can be used in the form of heat-curable compositions to form surface coatings.

Based on the product of the method according to the invention, heat-curable compositions can be prepared which include 100 parts by weight of a reaction product of (A), (B) and (C), calculated on the basis of the solids content (defined below) and 2 to 200 parts by weight , preferably 25 to 150 parts by weight, calculated on the basis of the solids content, of an aminoplast, phenol-formaldehyde resin, or a block polyisocyanate, wherein the aminoplast or phenol-formaldehyde resin has at least two groups of the formula:

connected directly to an amide nitrogen atom or atoms or connected directly to carbon atoms in a phenol ring, where R stands for a hydrogen atom or an alkyl group with from 1 to 6 carbon atoms. For use in such heat-curable compositions, it is preferred that the reaction product of (A), (B) and (C) has alcoholic hydroxyl groups, which e.g. secondary alcoholic hydroxyl groups in the residue of formula -CH2-CH(OH)-CH2- in the main chain of a product derived from an epoxy resin or phenoxy resin, or hydroxy-alkyl groups attached to the phenolic rings as described above.

Such compositions in a form suitable for use as a surface coating will usually also contain water and a smaller proportion, compared to the volume of the water, of an organic solvent, such as e.g. an ether, alcohol, ketone, or ester, especially 2-butoxyethanol or n-butanol. Methylolated compounds which can be used to prepare the compositions include urea-formaldehyde condensates, amino-triazine-formaldehyde condensates, especially melamine-formaldehyde and benzoguanamine-formaldehyde condensates, and phenol-formaldehyde condensates. If desired, these can be preferred, i.e. n-butyl ethers can be used. In many cases, the methylolated compounds and ethers thereof are not themselves water-soluble or dispersible in water. Incorporation of a product made according to the invention facilitates the dispersion or dissolution of such materials in water, and provides stable solutions or dispersions of the mixtures.

Examples of suitable block polyisocyanates (i.e. those which are stable in the aqueous dispersion at room temperature, but which become reactive on heating) include di- and poly-isocyanates blocked with caprolactam, an oxime (e.g. cyclohexanone oxime), a monovalent phenol ( e.g. phenol itself, p-cresol, and p-tert.butylphenol), or a monohydric aliphatic, cycloaliphatic, or araliphatic alcohol (e.g. methanol, n-butanol, decanol, 1-phenylethanol, 2- ethoxyethanol, and 2-n-butoxyethanol). Suitable isocyanates include aromatic diisocyanates such as e.g. m-phenylene, 1,4-naphthylene, 2,4- and 2,6-tolylene, and 4,4'-methylenebis-(phenylene) diisocyanates, and also their prepolymers with glycols (e.g. ethylene and propylene glycol ), glycerol, trimethylolpropane, pentaerythritol, diethylene glycol, and addition products of alkylene oxides with these aliphatic two- and multi-chain alcohols.

The compositions can be cured by heating to 100°C to 275°C, preferably 150°C to 225°C, for from 30 seconds to 1 hour, preferably from 2 to 30 minutes.

in

Other water-soluble or water-dispersible film-forming substances can also be included, such as e.g. alkyd resins and acrylic resins. The amount of such materials may vary within wide limits, but should not be so great as to mask the beneficial properties of the compositions. Typically, concentrations of up to 50%, and preferably up to 30%, are used, these percentages are based on the solids content of the materials.

The term "solids content" used in the present description and claims is understood to mean the percentage residue left after a sample of 1 g of the material has been heated in an open dish with a diameter of 5 cm in an oven at 120°C for 3 hours at atmospheric pressure.

When the reaction product from (A), (B) and (C) contains a hydroxyalkyl group having from 1 to 4 carbon atoms, such as e.g. a methylol group, it can be heat-cured without the addition of an aminoplast, a phenol-formaldehyde resin, or a block-formed polyisocyanate.

Coating of a surface can be carried out by

the surface is applied to the reaction product from (A),

(B) and (C) substituted with a hydroxyalkyl group -having from 1 to 4 carbon atoms, and the coated surface is heated to a temperature in the range from 100°C to 275°C, preferably from 150°C to 225°C, for from 30 seconds to 1 hour, and preferably from 2 to 30 min. to harden the product.

The surfaces to be coated with the compositions mentioned above are preferably of primed metal or untreated metal, especially a ferrous metal, but can also e.g. be made of wood or of a heat-resistant synthetic material.

The compositions may be applied by dipping, brushing, rolling, spraying (including electrostatic spraying), by electrolytic deposition, or by any other conventional method. The compositions can, if desired, include pigments and dyes. Other materials that can be incorporated include retarding agents such as e.g. calcium carbonate, calcium sulfate, barium sulfate, and magnesium silicate, surfactants, flow improvers, and plasticizers. They can also contain a strong acid, e.g. an aromatic sulphonic acid or its salt with an amine or ammonia as catalyst.

The present invention is illustrated in more detail by means of the following examples where all percentages indicate weight-%.

The starting materials used in the examples were prepared in the following way:

Phenol I

Epoxy resin I, a liquid diglycidyl polyether of 2,2-bis(4-hydroxyphenyl)propane (359 g; epoxy content 5.35 equivalents/kg), 2,2-bis(4-hydroxyphenyl)propane (246 g), p-tert .butylphenol (20 g) and 10% aqueous sodium hydroxide solution (0.39 g) are stirred and heated under nitrogen to 180°C. The molar ratio between epoxy resin and bisphenol and monovalent phenol is 1:1.14:0.14. An exothermic reaction starts and the temperature of the mixture rises spontaneously to 207°C. The mixture is cooled to 180°C and stirred at this temperature for 3 1/2 hours to give phenol I, a phenolic hydroxyl group-terminated resin having a negligible content of epoxy groups and an average molecular weight of 1880.

Phenol II

Epoxy resin I (2500 g) is stirred and heated under nitrogen to 120°C. p-Tert-butylphenol (75 g) and 2,2-bis(4-hydroxy-phenyl)propane (897 g) are added followed by a solution comprising sodium hydroxide (0.25 g), water (10.70 g) and methanol (3.50 g) and the temperature is increased to 160°C. The molar ratio of epoxy resin to bisphenol and monovalent phenol is 1:0.57:0.07. An exothermic reaction starts and the temperature of the mixture rises spontaneously to 210°C. The mixture is cooled to 190°C and stirred at this temperature for a further two hours, after which it has an epoxy content of 1.41 equivalents/kg. 2,2-Bis(4-hydroxyphenyl)propane (865 g) is added and the mixture is stirred for a further 2 hours at 190°C to give phenol II, a phenolic hydroxyl group-terminated resin having a negligible content of epoxy groups ( not more than 0.045 equivalents/kg) and an average molecular weight of 1945.

Phenol III

This is produced in a similar way to phenol II, except that the molar ratio between epoxy resin and the first bisphenol additive and monovalent phenol and the second bisphenol additive is 1:0.58:0.04:0.55. The epoxy content after the first bisphenol addition is 1.41 equivalents/kg. After the second bisphenol addition, the mixture is stirred and heated to 195°C for 5 hours to give phenol III, a phenolic hydroxyl group-terminated resin having a negligible epoxide content (not more than 0.05 equivalents/kg) and an average molecular weight in 2035.

Phenol IV

Epoxy resin I (338 g), 2,2-bis(4-hydroxyphenyl)propane (225 g) and 5% aqueous sodium hydroxide solution (0.5 g) are stirred and heated under nitrogen to 160°C. The molar ratio between epoxy resin and bisphenol is 1 :1,2. An exothermic reaction starts and the temperature rises to 202°C. The mixture is cooled to 180°C and stirred at this temperature for 2 hours. 2-Butoxyethanol is added and the reaction continues at 180°C for a further 3 hours so that obtains phenol IV, a phenolic hydroxyl group-terminated resin having a molecular weight of 2900 and a negligible epoxy content.

Example 1

A solution of phenol I (50 g; 0.027 mol) in 2-butoxyethanol (8.8 g) and n-butanol (10 g) is heated to 120°C in a flask fitted with a stirrer, condenser, dropping funnel and thermometer. A monomer/initiator mixture consisting of:

is added over the course of 2 hours via the dropping funnel to the solution of phenol I. The reaction is continued at 120°C for a further 2 hours before another portion of benzoyl peroxide (0.2 g) is added and the reaction is continued for another hour. A second monomer/initiator mixture consisting of: is added over the course of 1 hour. A further portion of benzoyl peroxide (0.2 g) is added and the reaction is continued at 120°C for two hours. The reaction mixture is cooled to 100°C, then added:

<*> 80% aqueous solution of 2-(dimethylamino)-2-methylpropan-1-ol.

The reaction mixture is heated for 1/2 hour to 100°C, then cooled to 90°C. Paraformaldehyde (2.5 g; 91% active content, 0.076 mol) is added and the temperature is maintained at 85°C for 6 hours, at which time the free formaldehyde content was determined to be 0.7%. The resinous product is diluted with water, so that a stable emulsion is formed which has a solids content of 25% and which can be diluted completely with water.

Example 2

A solution of phenol IV (.50 g; 0.018 mol) in 2-butoxyethanol (10 g) and n-butanol (10 g) is heated to 120°C in a flask fitted with a stirrer, condenser, dropping funnel and thermometer. A monomer/initiator mixture consisting of:

is added over the course of 2 hours via the dropping funnel to the solution of phenol IV. The reaction is continued at 120°C for a further 2 hours before another portion of benzoyl peroxide (0.2 g) is added and the reaction continues for another hour. A second monomer/initiator mixture consisting of: is added over the course of 1 hour. A further portion of benzoyl peroxide (0.2 g) is added and the reaction is continued at 120°C for 2 hours. The reaction mixture is cooled to 100°C and the following mixture is added:

The reaction mixture is heated to 100°C for half an hour, and then cooled to 90°C. Paraformaldehyde (2.5 g; 91% active/content, .0.076 mol) is added and the temperature is maintained at 85°C for 6 hours, at which time the content of free formaldehyde is measured to be 0.8%. Free styrene cannot be detected in the product using gas chromatography. After addition of further DMAMP-80 (1.8 g), the reaction product is diluted with water so that a stable emulsion is formed which has a solids content of approx. 25% and completely can be diluted with water.

Example 3

A solution of phenol I (50 g; 0.027 mol) in 2-butoxyethanol (10 g) and n-butanol (10 g) is heated to 120°C in a flask fitted with a stirrer, condenser, dropping funnel and thermometer. A monomer/initiator mixture consisting of:

is added over the course of 2 hours via the dropping funnel to the solution of phenol I. The reaction is continued at 120°C for a further 2 hours before another portion of azobis(isobutyronitrile) (0.2 g) is added and the reaction continues for another 1 hour . A second monomer/initiator mixture consisting of: is added over the course of 1 hour. Another portion of azobis(iso-butyronitrile) (0.2 g) is added and the reaction is continued at 120°C for a further 2 hours. The reaction mixture is cooled to 100°C and the following mixture is added:

The mixture is heated to 100°C for 1/2 hour, and cooled

then to 90°C. Paraformaldehyde (2.5 g; 91% active content, 0.076 mol) is added and the temperature is maintained at 85°C for 6 hours, at which time the free formaldehyde content was measured to be 0.3%. The resinous product is diluted with water so that a stable emulsion is formed which has a solids content of 25% and can be fully diluted with water.

Example 4

A solution of phenol I (50 g; 0.027 mol) in 2-butoxyethanol (10 g) and n-butanol (10 g) is heated to 120°C in a flask fitted with a stirrer, condenser, dropping funnel and thermometer. A monomer/initiator mixture consisting of: is added over the course of two hours via the dropping funnel to the solution of phenol I. The reaction is continued at 120°C for a further 2 hours before another portion of cumene hydroperoxide (0.2 g) is added and the reaction is continued for another one hour. A second monomer/initiator mixture consisting of:

is added within 1 hour. Another portion of cumene hydroperoxide (0.2 g) is added and the reaction is continued at 120°C for a further 2 hours. The reaction mixture is cooled

to 100°C and the following mixture is added:

The reaction mixture is heated to 100°C for 1/2 hour, and then cooled to 90°C. Paraformaldehyde (2.5 g; 91% active content, 0.076 mol) is added and the temperature is maintained at 80°C for 6 hours, at which time the content of free formaldehyde is measured to be 0.45%. The resinous product is diluted with water so that a stable emulsion is formed which has a solids content of 25% and can be fully diluted with water.

Example 5

A solution of phenol III (500 g; 0.25 mol) in 2-butoxyethanol (100 g) and n-butanol (100 g) is heated to 120°C in a flask fitted with a stirrer, condenser, dropping funnel and thermometer. A monomer/initiator mixture consisting of:

is added over the course of 2 hours via the dropping funnel to the solution of phenol III. The reaction is continued at 120°C for a further 2 hours before another portion of cumene hydroperoxide (2.0 g) is added and the reaction is continued for another hour. A second monomer/initiator mixture consisting of: is added over the course of 1 hour. Another portion of cumene hydroperoxide (2.0 g) is added and the reaction is continued at 120°C for a further 2 hours. The reaction mixture is cooled to 100°C and the following mixture is added:

The reaction mixture is heated to 100°C for 30 min., and then cooled to 90°C. Paraformaldehyde (25 g; 91% active content, 0.76 mol) is added and the temperature is maintained at 85°C for 6 hours, at which time the free formaldehyde content was measured to be 0.45%. The resinous product is diluted with water so that a stable emulsion is formed which has a solids content of 25% and can be fully diluted with water.

Example 6

A solution of phenol I (50 g; 0.027 mol) in 2-butoxyethanol (10 g) and n-butanol (10 g) is heated to 120°C in a flask fitted with a stirrer, condenser, dropping funnel and thermometer. A monomer/initiator mixture consisting of:

is added over the course of 2 hours via the dropping funnel to the solution of phenol I. The reaction is continued at 120°C for a further 2 hours before another portion of cumene hydroperoxide (0.2 g) is added and the reaction is continued for 2 hours. A second monomer/initiator mixture consisting of: is added over the course of 1 hour. Another portion of cumene hydroperoxide (0.2 g) is added and the reaction continues at 120°C for a further 2 hours. The reaction mixture is cooled to 100°C and the following mixture is added:

The reaction mixture is heated to 100°C for 1/2 hour, and then cooled to 90°C. Paraformaldehyde (2.5 g; 91% active content, 0.076 mol) is added and the temperature is maintained at 85°C for 6 hours. The resinous product is diluted with water so that a stable emulsion is formed which has a solids content of 25% and can be fully diluted with water.

Example 7

A solution of phenol III (320 g; 0.13 mol) in 2-butoxyethanol (155.4 g) and n-butanol (155.4 g) is heated to 110°C in a flanged flask equipped with a stirrer, condenser, nitrogen purge, temperature recording and inlet from a peristaltic feed pump. Benzoyl peroxide (70% in water, 0.55 g) is added and the styrene supply is started at 0.8 ml min.<->"'", 80 g of styrene is added during 90 min. and further additions of benzoyl peroxide are made after 30 min. (1.55 g), 60 min. (1.55 g) and 90 min. (3.1 g). The mixture is heated to 110°C for a further 2 hours. Aspartic acid (21.2 g, 0.16 mol) and 2-(dimethylamino)-2-methylpropan-1-ol (80% aqueous solution, 23.6 g; 0.16 mol) are added and the mixture is stirred for 15 min. , and then cooled to 80°C. Paraformaldehyde (14.2 g; active content 91%, 0.34 mol) is added and the temperature is maintained at 80°C for 3 hours. The resulting resinous product solution has a solids content of 56% and can be fully diluted with water.

Example 8

Example 7 is repeated by using phenol I (320 g; 0.17 mol) instead of phenol III. The product has a solids content of 56% and can be fully diluted with water.

Example 9

An epoxy resin having an epoxy content of 1.52 equivalents/kg (499.1 g), prepared by reacting epoxy resin I with 2,2-bis(4-hydroxyphenyl)propane, is heated to 145°C and a mixture of styrene ( 99.8 g) and cumene hydroperoxide (80% solution in cumene, 5.5 g) are added via the peristaltic pump over a period of 1 hour. The reaction is continued at 145°C for a further 2 hours. 2,2-Bis(4-hydroxyphenyl)propane (124.5 g, 0.55 mol) is added and the temperature of the reaction mixture is slowly raised to 190°C over a period of 5 hours, after which the epoxy content is negligible. 2-Butoxyethanol (285 .2 g) and n-butanol (285.2 g) are added and the resulting solution is cooled to 110° C. Aspartic acid (36.4 g,

0.27 mol) and 2-(dimethylamino)-2-methylpropan-1-ol (80% aqueous solution, 40.6 g; 0.28 mol) are added and the reaction mixture is cooled to 80°C. Paraformaldehyde (24.3 g; 91% active content, 0.74 mol) is added and the temperature of the mixture is maintained at 80°C for 3 hours. The resulting solution of resinous product has a solids content of 56% and can be fully diluted with water.

Example 10

Phenol II (722 g; 0.37 mol) is dissolved in 2-butoxyethanol (350.6 g) and n-butanol (350.6 g) at 120°C. A solution containing cumene hydroperoxide (80% solution in cumene, 7.6 g) and styrene (144.4 g) is added via a peristaltic pump over 150 min., and the mixture is heated to 120°C for a further 3 hours. The solution is cooled to 110°C and aspartic acid (47.8 g; 0.36 mol) and 2-(dimethylamino)-2-methylpropan-1-ol (80% aqueous solution; 53.2 g; 0.36 mol) ) is added. After cooling to 80°C, paraformaldehyde (32.0 g; 91% active content, 0.97 mol) is added and the mixture is stirred at 80°C for 3 hours. The resulting resinous product solution has a solids content of 58% and can be fully diluted with water. A mixture of the product with a commercially available butylated urea-formaldehyde resin having a solids content of 53%, at a solids ratio of 90:10, on dilution with water gave an emulsion which had a solids content of 25% and was suitable for use as a coating composition. sentence, and had a viscosity (Ford B4 cup) of 13 seconds.

Example 11

A solution of phenol I (50 g; 0.027 mol) in 2-butoxyethanol (10 g) and n-butanol (10 g) is heated to 120°C. A monomer/initiator mixture consisting of:

is added dropwise to the solution over 2 hours. The reaction is continued at 120°C for a further hour before another portion of cumene hydroperoxide (0.2 g) is added and the reaction is continued at 120°C for 2 hours. A second monomer/initiator mixture consisting of: > is added drop by drop over the course of 1 hour. Another portion of cumene hydroperoxide (0.2 g) is added and the reaction is continued at 120°C for a further 2 hours. The reaction mixture is cooled to 100°C and the following mixture is added:

The mixture is kept at 100°C for 30 min., and then cooled to 90°C. Paraformaldehyde (2.5 g; 91% active content, 0.076 mol) is added and the temperature is maintained at 85°C for 6 hours, at which time the content of free formaldehyde is measured to be 0.6%. The resulting solution of resinous product is fully dilutable with water. A mixture of the product with a commercially available butylated urea-formaldehyde resin having a solids content of 53% in a solids ratio of 90:10 gives, when diluted with water, an emulsion having a solids content of 25% and is suitable for use as a coating compound. sentence, the emulsion has a viscosity (Ford B4 cup) of 26 seconds.

Example 12

A solution of phenol I (50 g; 0.027 mol) in 2-butoxyethanol (20 g) is heated to 120°C. A monomer/initiator mixture consisting of:

is added dropwise to the solution over 2 hours. The reaction is continued at 120°C for a further 1 hour before another portion of cumene hydroperoxide (0.2 g) is added and the reaction is continued at 120°C for 2 hours. A second monomer/initiator mixture consisting of: is added dropwise over the course of 1 hour. Another portion of cumene hydroperoxide (0.2 g) is added and the reaction is continued at 120°C for a further 2 hours. The reaction mixture is cooled to 100°C and the following mixture is added:

The mixture is kept at 100°C for 30 min., and then cooled to 90°C. Paraformaldehyde (5.5 g; 91% active content, 0.168 mol) is added and the temperature is raised to the reflux temperature (137°C). The mixture is held at the reflux temperature for 6 1/2 hours, at which time the free formaldehyde content is 0.35%. The resulting solution of resinous product can be fully diluted with water.

Example 13

A coating composition is prepared by mixing the product of Example 5 with a commercially available butylated phenol formaldehyde resin, in the form of a solution (56% solids content) in n-butanol containing a small amount of toluene, at a solids ratio of 70:30. The composition is applied to a tin-coated steel plate by swirl coating, this gives a coating that is 2 to 4 um thick. The plates are heated to 200°C for 10 min. to harden the coating. The cured coating shows no defects after immersion in boiling 2% acetic acid for 6 hours.

Example 14

A coating composition is prepared by mixing the product of Example 7 with a commercially available butylated urea-formaldehyde resin with a solids content of 53%, in a ratio of 90:10 calculated on the basis of solids content and diluting the mixture with water so that an emulsion is formed having a solids content of 25%. The viscosity of the emulsion is measured. The emulsion is applied to an electrolytic tin plate as a film mea*«thickness 2 to 4 µm and cured by heating to 215°C for 3 min. The resulting coated tin plate is examined. The results from the viscosity measurements and investigations of the cured coating are reproduced below:

Emulsion viscosity (Ford B4 cup) Greater than 100 sec.

<*> The MEK rub test involves giving the coated surface double rubs with cotton soaked in methyl ethyl ketone. The result is stated as the number of such

rubbings required before the coating shows the first signs of being attacked.

the wedge bending test involves impact bending the specimen over a mandrel 10 cm long and having an outer diameter of 6 mm at one end and tapering to a point on the

other end. The sample is then examined to determine the percentage of the length of the sample where the coating did not peel off.

The hatched cross-adhesion test involves using a knife to cut parallel lines 3 mm apart in the hardened coating in one direction, and two other parallel lines cutting these at a 90° angle. A piece of adhesive tape is then pressed over the cut the area. The tape is pulled off with a rapid and continuous movement and the area is examined for the removal of coating. The percentage of the area from which the coating has not been removed is indicated. <4> the pasteurization tests include heating the samples in water, steam and the indicated acids in the indicated time periods, the coated surface is then examined for whitening and the hatched cross test is repeated.The adhesion and whitening properties are indicated according to a scale of 0 to 5, where 0 indicates excellent adhesion and no whitening and 5 indicates poor results for these properties.

Claims (13)

1. Process for the production of resinous products which can be diluted with water by reacting (A) a resin which has at least one phenolic hydroxyl group and a free position in the ortho- and/or para-position to the phenolic hydroxyl group, with (B) a aldehyde and (C) a sulfuric acid or an organic acid containing a primary or secondary amino group or a mercaptan group and a carboxylic acid, sulphonic acid or phosphonic acid group, or a water-soluble salt thereof, characterized in that the resin (A) contains a residue formed by polymerization of a vinyl monomer in the resin, or a precursor thereof. 2. Method according to claim 1, characterized in that a resin is used as (A) which is produced by reacting an epoxy resin and a polyhydric phenol with a free position in the ortho and/or para position to the phenolic hydroxyl group of a resin with terminal phenolic groups and subsequent polymerization of a vinyl monomer in the resin with terminal phenolic groups, 3. Process according to claim 1 or 2, characterized in that a resin is used as (A) which is produced by polymerization of a vinyl monomer in an epoxy resin with a secondary alcoholic hydroxyl group, where the product obtained is reacted with a polyhydric phenol with a free position in ortho - and/or para-position to a phenolic hydroxyl group of a resin with terminal phenolic groups. 4. Process according to claim 2 or 3, characterized in that a bisphenol of formula I is used as the polyvalent phenol in which R<1>, independently of each other, represents a hydrogen atom, a halogen atom, an alkyl group with 1-4 C atoms, or an alkenyl group with 2-4 C atoms, provided that at least one of the groups R<1> in the ortho position to a phenolic hydroxyl group is a hydrogen atom, and X is an alkylene or alkylidene group with 1-3 C atoms, a carbonyl or sulfonyl group, an oxygen or sulfur atom, or a covalent bond. 5. Method according to one of claims 2-4, characterized in that the vinyl monomer, together with a polymerization initiator that forms free radicals, is mixed with the resin with terminal phenolic groups, the epoxy resin precursor or a solution thereof, in an organic solvent and the mixture is heated to 60- 200"C. 6. Method according to one of claims 1-5, characterized in that the vinyl monomer is used in such an amount that it constitutes up to 50% by weight of the resin (A). 7. Process according to one of claims 1-6, characterized in that a styrene, acrylic acid, methacrylic acid or an ester thereof, acrylamide, methacrylamide or a hydroxyalkyl derivative thereof, a vinyl ester of a carboxylic acid, or a mixture of two or more of these are used as vinyl monomer the connections. 8. Method according to one of claims 5-7, characterized in that a peroxide or an azo compound is used as polymerization initiator, present in an amount of 1-20% by weight of the monomer. 9. Method according to one of claims 1-8, characterized in that an aliphatic aldehyde with 1-6 C atoms is used as aldehyde (B). 10. Method according to one of the claims 1-8, characterized in that (C) is used a mercaptocarboxylic acid of the formula IV in which R<7> stands for an aliphatic, aromatic or araliphatic, divalent group with up to 10 C atoms, which may contain an additional carboxylic acid group, or an aminocarboxylic acid of the formula V in which R<8> stands for an aliphatic, aromatic or araliphatic, bivalent group with up to 10 C atoms, which may contain an additional carboxylic acid group, R<9> stands for a hydrogen atom, a group of the formula VI or an alkyl group with 1-6 C atoms, which may be substituted with another carboxylic acid group or a group of the formula -CH(R1<0>)OH or -CH(R1<0>)OR12, provided that R< 8> and R<9> together do not contain more than 1 carboxylic acid group, R^<0> stands for a hydrogen atom, an alkyl group with 1-4 C atoms, or an aryl group with 6-10 C atoms, R<11> stands for a hydrogen atom, a carboxyl group or an alkyl group with 1-6 C atoms, which may be substituted with a carboxylic acid group or a group of the formula -CH(R10)OH or -CH(R<12>)OR, and R12 stands for an alkyl group with 1-6 C atoms or an alkoxyalkyl group in which the alkoxy and the alkyl group each have 1-6 C atoms. 11. Method according to claim 10, characterized in that glycine, glutamic acid, aspartic acid, p-aminobenzoic acid, sarcosine or thioglycolic acid are used as (C). 12. Method according to one of the preceding claims, characterized in that (A), (B) and (C) together, in an inert solvent, are heated to a temperature between 60 and 180°C, in the presence of a sufficient amount of base to least partially to neutralize any free acid present. 13. Method according to one of the preceding claims, characterized in that 0.3 to 2.0 mol of component (C) is used per mol of phenolic hydroxyl groups in (A) and 1.1 to 4.0 mol of component (B) per moles (C).