NO165869B - Rotary crushers with blades. - Google Patents

Abstract

The rotor of the crusher receives the stones at its centre. It comprises three blades (20, 21) which, except on the ejecting edges (22), are protected against internal wear by their hollow shape which retains a protective layer of stones. These edges are protected from impacts by protecting plates (24) arranged radially in front of them. <IMAGE>

Description

Process for the production of epoxy resin esters.

The invention relates to a method for the production of epoxy resin esters containing carboxylic acid and hydroxyalkyl ester groups.

The epoxy resin esters produced by the present method can be used as aqueous coatings and are excellently suitable for application by electrophoretic methods.

The present invention thus provides a method for the production of modified epoxy resin esters, in that

A. a glycidyl ether of a divalent phenol is esterified with an unsaturated fatty acid in sufficient amounts to react with at least approx. 90 per cent of the hydroxyl groups in the glycidyl ether in which one epoxide group is considered equivalent to two hydroxyl groups, and that

B. the adduct of the obtained fatty acid ester with at least 8 wt% maleic anhydride, calculated on the weight of the entire preparation, is formed, and the method is characterized by C. 0.25 to 0.75 of the carboxylic acid equivalents. of the maleic anhydride adduct is hydroxyalkylated with a hydroxyalkylation agent.

The preparations hydroxyalkylated by the present method have improved dispersibility in water at lower amine equivalents. Feed preparations with a high solids content can easily be prepared for electrolysis baths. When used in electrophoretic coating applications, the resins exhibit high mass transfer, thereby requiring less electrical current to coat an object with a given amount of resin. Primary coatings made from these preparations have excellent corrosion resistance, especially salt shower resistance. In addition, the hydroxy groups in the preparations act as crosslinking areas for reaction with other resins, such as aminoplast resins.

The epoxy resins used in the method according to the invention are low molecular weight glycidyl ethers of divalent phenols. Although fatty acid esters of high molecular weight glycidyl ethers of divalent phenols can be prepared, these high molecular weight esters are prone to gelation during the subsequent reaction with maleic anhydride. The glycidyl ethers of divalent phenols used according to the invention are therefore preferably selected on the basis of their molecular weight so that subsequent reaction of the esters with maleic anhydride will not lead to gel formation. The particular molecular weight will also depend somewhat on the hydroxy functionality of the glycidyl ether, and it is thus difficult to specify a suitable upper limit for the molecular weight of the glycidyl ethers that can be used. Experiments to date have shown that glycidyl ethers of divalent phenols with an average molecular weight of less than approx. 700 in general can be used in carrying out the present invention without gelation during the maleic anhydride addition reaction.

The preferred epoxy resins that can be used in the present invention are the diglycidyl ether of p,p'-dihydroxydphenylpropane, which is referred to as the diglycidyl ether of bisphenol A. The commercially produced diglycidyl ether of bisphenol A has an epoxy equivalent weight of approx. 190 and a melting point of approx. 8°C. It can be produced e.g. by converting 1 mol of bisphenol A in 10 mol of epichlorohydrin using approx. 2 mol sodium hydroxide as dehydrohalogenating agent. The diglycidyl ethers of other divalent phenols which can also be used according to the invention include p,p'-dihydroxybiphenyl, p,p'-dihydroxybiphenylmethane, p,p'-dihydroxybiphenylethane, resorcinol, hydroquinone, dihydroxy-naphthalene, dihydroxydiphenylsulfone, dihydroxy-benzophenone and the like.

Mixtures of glycidyl ethers of divalent phenols can also advantageously be used according to the invention as long as the average molecular weight of the mixture is sufficiently low to prevent gel formation when the fatty acid esters thereof are reacted with maleic anhydride. An example of a high-molecular diglycidyl ether that can be used in a mixture with lower-molecular glycidyl ethers is the reaction product of 1.57 mol of epichlorohydrin and 1 mol of bisphenol A with approx. 1.8 moles of sodium hydroxide. The glycidyl ether thus formed has an epoxy equivalent weight of approx. 500. This glycidyl ether can advantageously be used in a mixture with the diglycidyl ether of bisphenol A up to at least approx. 60 vekitpst. of the entire epoxy resin mixture.

The unsaturated fatty acids used in the production of the fatty acid epoxy resin esters are unsaturated fatty acids with from approx. 11 to 24 carbon atoms. Such unsaturated fatty acids are usually obtained from drying oils, but may be obtained from any desired source. Examples of fatty acids that can be used include linoleic acid, oleic acid, linolenic acid, dehydrated ricinoleic acid, etc. Mixtures of unsaturated fatty acids can also be used. Such compounds are named after the oils from which they are derived, and include tallow, linseed, Chinese tree oleic, soybean oleic and dehydrated castor oleic acids. Acids which have been shown to be particularly useful in the present invention are the linoleic acids. The preferred unsaturated fatty acids are those derived from unsaturated diglycerides with an iodine value of from approx. 135 to approx. 210.

The amount of fatty acid used to esterify the epoxy resins should be practically equivalent to the hydroxyl functionality of the epoxy resin. When determining the hydroxyl functionality of the epoxy resin, one epoxide group is considered equivalent to two hydroxyl groups. If therefore the epoxy resin contains an average of two epoxide groups per molecule and practically no hydroxyl groups, the hydroxyl functionality is 4. Approx. 4 mol of unsaturated fatty acid are then reacted with 1 mol of the epoxy resin, which gives a minimum of hydroxyl groups in the thus formed ester. It is important that the hydroxyl content of the ester is low as the ester is later reacted with maleic anhydride. The anhydride groups in the maleic anhydride can react with hydroxyl groups in the ester. As an addition reaction takes place between the unsaturation in the maleic anhydride and the unsaturated groups in the fatty ester, a further addition reaction of anhydride and hydroxyl groups can lead to cross-linking and subsequent gel formation. The exact amount of residual hydroxyl groups that can be tolerated in the fatty acid esters of the epoxy resins will vary somewhat depending on the particular epoxy resin used, the particular fatty acid with which the epoxy resin is esterified, as well as the reaction conditions. In general, it is preferred to esterify at least approx. 90 percent of the hydroxyl functionality so that gel formation does not occur during subsequent reactions.

It is advantageous to esterify the epoxy resin with an amount of fatty acid that is practical

equivalent to the hydroxyl functionality of the epoxy resin and to continue the esterification reaction by means of heat, generally at a temperature from about 204°C to approx. 260°C, incl

removal of the water of esterification until the acid number of the reaction mixture falls to approx. 15 or lower, preferably below approx. 10. The details for carrying out the esterification of epoxy resins are well

known to those skilled in the art and will not be discussed in detail here.

The epoxy resins can be modified with different components before the esterification with the fatty acids. Monovalent phenols can e.g. is reacted with the epoxy resins to form epoxy resins with lower hydroxyl functionality. The amount of monovalent phenol that can be used can vary from a fairly small amount up to approx. 1 mol of phenol for each epoxide group in the epoxy resin.

The epoxy resins can also be esterified with mixtures of unsaturated fatty acids and saturated acids as long as the percentage of unsaturated fatty acids is kept at a sufficiently high level to ensure the presence of residual fatty acid unsaturation (a minimum of at least about 3 unsaturated groups per molecule) in the product which is obtained after reaction with maleic anhydride. Examples of saturated acids which can be used in mixture with the unsaturated fatty acids include benzoic acid, acetic acid, butyric acid, hexanoic acid, stearic acid and so on. The amount of saturated acid that can be used will depend on the degree of defatting of the fatty acid that is used in mixture with it, but in general saturated acids can be up to approx. 50 mole parts, calculated on the total acids, is used.

The addition reaction of the fatty acid ester of the epoxy resin with maleic anhydride can be carried out by simply mixing the fatty acid epoxy resin ester with the appropriate amount of maleic anhydride and heating the reactants until the addition of maleic anhydride to the unsaturated groups of the fatty acid ester is complete. This reaction is generally carried out at a temperature from approx. 171°C to approx. 216°C, and preferably from approx. 182°C to approx. 193°C.

The completeness of the reaction between maleic anhydride and the fatty acid epoxy resin esters can be determined by a permanganate test. The test consists in extracting part of the fatty acid epoxy resin addition product with an equal amount of water and adding to 2 ml of the water extract a few drops of 0.05 N potassium permanganate solution. If the extract is bright red after 1-3 drops of permanganate solution have been added, there is no unreacted maleic anhydride left. The formation of a brown color indicates the presence of unreacted maleic anhydride and in that case the reaction is continued to complete the addition.

The amount of maleic anhydride which can be added to the fatty acid epoxy resin ester can be varied within relatively wide limits depending mainly on the end use of the adduct and especially on the degree of water solubility desired for the amine salts. In general, approx. 8 wt. maleic anhydride, calculated on the weight of the entire reaction mixture, to obtain the presence of sufficient free carboxyl groups in the product after the hydroxyalkylation to make the amine salts water soluble. The maximum amount of maleic anhydride that can be used will depend somewhat on the amount of entrainment present in the fatty acid epoxy resin ester and the end use of the preparations. Large amounts of maleic anhydride can lead to coating preparations with a low degree of stability and to coatings that have poor resistance to salt and alkali. In general, approx. 20 wt. maleic anhydride, calculated on the total weight of the reactants, be the maximum that can be used.

The fatty acid epoxy resin addition products can be modified by incorporating into the addition reaction various modifiers, such as drying oils, semi-drying oils, unsaturated hydrocarbon resins and copolymers thereof containing unsaturated groups. Examples of drying oils or semi-drying oils that can be used to modify the acid epoxy resin ester addition products include linseed oil, soybean oil, tallow oil, dehydrated castor oil, sunflower oil, safflower oil and the like. The amount of drying oil modification that can be used should be limited to such an amount that will not interfere disturbingly with the desirable properties of the addition product, including its stability, the obtained film properties and the water solubility of the amine salts. In general, such drying oils can be used to modify the condensates up to approx. 30 wt. of the entire preparation. The use of drying oils is advantageous for reducing the price of the condensate and for reducing the overall functionality thereof. The modification with drying oils can also be used to lower the viscosity and facilitate the handling of the undissolved resin materials where this is desirable or necessary.

The unsaturated hydrocarbon resins that can be used to modify the fatty acid epoxy resin addition products include polymerized fractions of coal tar distillates containing coumarone or indene or petroleum distillates containing cyclopentadiene or piperylene. Copolymers of the fractions or distillates with vinyl monomers, such as ethylene, isobutylene, styrene and the like, can also be used. Useful resins have softening points below approx. 121°C and iodine number in the range from 100 to 300. The use of such unsaturated hydrocarbon resins to modify the fatty acid epoxy resin ester addition products leads to harder films after the preparations are cured. The amount of unsaturated hydrocarbon resins that can be used can vary quite widely depending on the desired hardness of the films obtained. In general, quantities can be up to 25% by weight. calculated for the total reactants, is used without interfering with other valuable properties of the condensates.

According to the invention, part of the carboxylic acid equivalents of the anhydride groups in the preparations described above are hydroxyalkylated. The hydroxyalkylation reaction can be carried out by hydrolyzing the anhydride groups of the reacted maleic anhydride with water to form carboxylic acid groups. A portion of the carboxylic acid groups is then reacted with a monoepoxide compound to form a hydroxyalkyl ester. The amount of monoepoxide reacted with the hydrolyzed maleic anhydride epoxy resin ester can be varied to some extent. It is important that sufficiently converted carboxylic acid groups are back in the preparations so that the amine salts that are later formed are water-soluble. To achieve this water solubility, the hydroxyalkylated preparations should have an acid number of at least approx. 40. This minimal acid number is obtained by converting no more than approx. 75 percent of the carboxylic acid groups with the monoepoxide compound. The presence of a small amount of hydroxyalkyl groups in the modified epoxy resin ester preparations provides preparations with improved coating properties. However, it has usually been shown that the most remarkable improvements are obtained when at least approx. 25 percent of the hydroxyl acid equivalents of the reacted maleic anhydride are hydroxyalkylated. The improved coating products according to the invention have acid numbers varying from approx. 40 to approx. 160, and preferably from approx. 50 to approx. 100.

The monoepoxide compounds which can be used in the method according to the invention contain an epoxide group. on nab<p>carbon atoms and no other groups reactive with carboxylic acid groups under the conditions used. Examples of useful monoepoxy compounds are ethylene oxide, propylene oxide, butylene oxide, styrene oxide, butyl glycidyl ether, phenyl glycidyl ether, glycidyl acetate, glycidyl benzoate, etc.

The hydroxyalkylation reaction can be simply carried out by first hydrolyzing the anhydride groups of the maleic anhydride adduct with water, followed by reaction with the desired amount of monoepoxide precursor. The hydrolysis of the anhydride groups is carried out by bringing the resin material into contact with water equivalent to or in excess of the anhydride groups. Although the hydrolysis will take place at room temperature and without a catalyst, it is preferred to carry out the reaction at elevated temperatures in the range from approx. 38°C to approx. 93°C using a basic catalyst, such as tertiary amines, tertiary amine salts, quaternary ammonium bases and salts, as well as alkali metal hydroxides and alkaline earth metal hydroxides. The completeness of the hydrolysis reaction is determined by infrared analysis or by acid number. When the hydrolysis is complete, the resin material is hydroxyalkylated by reaction with the desired amount of monoepoxyd by simply heating the reactants at a temperature from 66° to 121°C until the reaction is complete according to the acid number determinations. Pressure above atmospheric pressure can be used to facilitate the reaction. The basic catalyst used in the hydrolysis reaction can serve as catalyst for the hydroxyalkylation reaction or further basic catalysts can be added.

Further hydroxyalkylation reagents which can be used in the method according to the invention are cyclic carbonates, monohalohydrins and aliphatic diols. Cyclic carbonates react with acids in practically the same way as monoepoxide compounds to form hydroxyalkyl esters, except that carbon dioxide is evolved in the reaction. When carrying out the reaction between cyclic carbonates and maleic anhydride epoxy resin esters, the anhydride groups of the maleic anhydride adduct are hydrolysed as described above, and the cyclic carbonate is reacted with the acid groups at elevated temperatures, approx. 121°C to approx. 204°C using basic catalysts as described above, until carbon dioxide ceases to evolve. Cyclic carbonates that can be used in the present invention are e.g. ethylene carbonate, propylene carbonate, butylene carbonate and octylene carbonate.

When the hydroxyalkylation reaction is carried out with a monohalide hydride, the anhydride groups are again first hydrolysed. The monohalohydrin is condensed with the acid groups to form hydroxyalkyl esters by a dehydro-halogenation reaction with eth-alkali, preferably sodium or potassium hydroxide. Monohalohydrins which can be used in the invention include ethylene chlorohydrin, propylene chlorohydrin, butyl bromohydrin, propylene iodohydrin, etc.

Hydroxyalkylation of the maleic anhydride epoxy resin esters can also be carried out by reacting the anhydride groups of the maleic anhydride with an aliphatic diol. A hydroxy group of the diol reacts with the anhydride group by opening the anhydride ring and forming an acid group and a hydroxyalkyl ester group. The hydroxyalkylation reaction with the aliphatic diol is carried out at elevated temperatures, generally at approx. 38°C to approx. 121°C using the basic catalysts indicated above. Aliphatic diols that can be used in the present invention are ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,3-butanediol, hexylene glycol, octethylene glycol, decanediol, etc., as such compounds -ser has two alcoholic hydroxyl groups and from 2 to approx. 20 carbon atoms in the chain. Other suitable diols are polyalkylene glycols, such as polyethylene glycols, polypropylene glycols and polybutylene glycols, polypropylene glycols and polybutylene glycols, where the molecular weights are from approx. 106 to approx. 1000. Suitable aliphatic diols are those containing two alcoholic hydroxyl groups and no other groups reactive with the carboxylic acid groups under the conditions used.

The hydroxyalkylated preparations produced according to the invention can be used in conventional paint formulations by dissolving the esters in organic solvents with or without pigmentation. Suitable organic solvents include aromatic and aliphatic hydrocarbons, esters, ethers, alcohols, ether alcohols, ester alcohols, and mixtures of these solvents. The solutions can be applied to suitable substrates by brushing, spraying, dipping, roller application, etc. The preparations can be used as air-drying or burning coatings. Particularly useful coatings are prepared by mixing the resin solutions with aminoplast resins, applying the mixture to the desired substrate and burning the formed coating to the heat-set stage.

It is particularly advantageous to use the hydroxyalkylated maleic anhydride epoxy resin esters as water-dispersed coating preparations. The term "water-dispersed coating preparations" is used herein to denote preparations where the resin is dissolved in, dispersed in or emulsified in water.

To make the preparations "water-dispersible", they are reacted with amines to form the salt of the amine and the carboxylic acid groups in the preparations. The amount of amine required to react with the carboxylic acid groups to render the salts water dispersible will depend to some extent on the particular amine employed as well as the particular modified epoxy resin ester reacted. In general, the modified epoxy resin ester can be made water-dispersible by reacting the ester with between 0.2 and 1.5 equivalents of amine for each carboxyl group in the condensate. The amine equivalence is based on the amino nitrogen and the acid groups on the acid number of the ester.

Examples of amines that can be used include ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, butylamine, dibutylamine, tributylamine, ethanolamine, propanolamine, dipropanolamine, triethanolamine, 2-amino-2-methyl-1-propanol, morpholine, ethylenediamine , propylene diaine, diethylaminopropylamine, and so on. Other amines can also be used.

The amines that can be used to react with the condensates can be water soluble or only partially water soluble. Triethylamine sr is an example of a partially water-soluble amine that can be used to advantage. The water solubility of triethylamine at 20°C is 5.5 percent.

Water-insoluble amines can also be used in admixture with water-soluble or partially water-soluble amines. Such water-insoluble amines include polyamido-amines prepared by reacting a mono- or poly-basic acid with an aliphatic polyamine in which the amino groups are in excess over the acid groups. Such polyamido-amines can be produced by reacting fatty acids, e.g. linseed oil fatty acids, soybean acids, tall oil acids, Chinese tree oleic acids and dimerized and trimerized fatty acids, with polyalkylene polyamines, such as diethylenetriamine, tripropylenetetramine, tetraethylenepentamine and the like. Up to as high as 40% by weight, calculated on the entire amine mixture, of polyamido-amine can be used in admixture with the water-soluble or partially water-soluble amines.

The amine salts of the modified epoxy resin esters can be formed by dissolving the amine in water and then slowly adding the condensate. It is preferred to heat the modified ester material before adding it to the amine-water solution. Heat makes the ester more fluid and easier to process, and it also facilitates the reaction of the ester with the amine.

Small amounts of water-soluble solvents, such as alcohols and ether alcohols, can be added to the amine salts in water to obtain a clear solution if desired.

Small amounts of water-insoluble solvents may be added to the modified epoxy resin ester prior to dissolution in water to make the condensate more fluid and to facilitate the dissolution process. Aromatic and aliphatic hydrocarbons, as well as certain esters and ketones can be used for this purpose.

Coatings can be prepared from the modified epoxy resin ester amine salts dispersed in water using conventional methods, such as spraying, roll coating, dip coating, brushing, etc. Solutions containing different percentages of solids can be used depending on the desired results. In general, solutions containing between 25 and 50 percent solids are used, and when these are applied to suitable substrates, the coatings can be air-dried at the ambient temperatures or they can be hardened by heating. Excellent films have been obtained by heating the coatings to between 149°C and 204°C for 15 to 45 minutes. Dryers can be used to harden the coatings, but they are not necessary in most cases.

Other water-soluble resins, particularly film-forming resins, may be incorporated into the water-dispersed amine salt-modified epoxy resin ester compositions to modify the properties of the coatings thus produced. Water-dispersible aminoplast resins, such as methylated, methylol-methylamine, have been found to be particularly advantageous. The use of water-soluble aminoplast resins generally leads to improved coating hardness as well as improved resistance to solvents, alkalis and salt spray. Until approx. 30% by weight, calculated on the weight of the entire resin mixture, of amino-plastic resin can be used.

The amine salts of the modified epoxy resin esters are particularly useful in electroplating or electrophoresis processes. In these processes, the amine salts can be distributed to 5-10% solids in water and used in an electrolysis bath. The object to be coated and which has an electrically conductive surface is made the anode and the container containing the coating preparation can be the cathode. The provision of an electrical potential between the anode article and the cathodic container causes the resin to deposit on the anode as a coating. After the object has been coated, it is removed from the cell and the coating is hardened to the insoluble infusible state by firing at a temperature of from approx. 149 to approx. 232°C.

It is preferred to use an electrophoretic coating bath by continuously passing objects to be coated through the bath and by continuously or periodically replacing the coating resin solid preparation in the bath as it is used up in the coating operation. When the electrophoresis process is operated continuously, the resin is exposed to heat (approximately 27°C to 49°C) as well as to an electric field. Under these conditions, the resin generally breaks down, preventing more than a few turns during continuous operation. A "round" is defined as the point at which the total added solids are equal to the weight of the initial solids in the bath. The water-dispersed amine salts have a very long and useful life when used in the electrophoresis coating process, and no degradation of the resin is observed even after 20 passes.

When the amine salts are used in electrophoresis processes, the modified epoxy resin ester is separated on the anode and the amine is discharged at the cathode and dissolves again. A small amount

of the amine, however, is carried by the resin to the anode, becomes enclosed in the film, and thus leaves

the bathroom. This condition leads to a depletion of the resin and of the amine in the bath, as the resin is depleted at a much greater rate than the amine. To keep the solids in the bath on

the desired constant level and pH in the bath constant, (as desired between about 7 and 8.5), the resin and amine are added to the bath, either continuously or from time to time, at a rate approximately equal to their depletion rate. This renewal of the bath requires a feed material with a high solids content that is rich in resin and with a low amine content. Feed materials with high solids can be prepared quite easily from the preparations according to the invention. The modified epoxy resin esters according to the invention can, when reacted with a small amount of amine, be fairly easily emulsified in water at a high solids content. The emulsions formed are quite liquid and can be fed in the bath

without much difficulty. Once in the bath, the emulsions are quickly dispersed through the bath without any interruption or disturbance of the coating process.

The water-distributed amine salts have good settling ability when used in the electrophoresis process. By the term "deposition ability" is meant the ability of the resin to cover or coat areas of anode objects that are not easily accessible, such as retracted areas, small defects and imperfections, and areas that do not face the cathode.

When performing electrophoresis-plating processes, the voltages and amperages will vary depending on the desired film thickness of the coating and the duration of the coating operation. Increasing the voltage increases the amount of resin preparation deposited in a given time. The amine salts are very stable and show no degradation or breakdown under widely varying electrical potentials. Moreover, the amine salt preparations have a high mass transfer under the influence of an electric current and require a small amount of electricity to transport a given amount of resin.

Coatings or films of the modified epoxy resin esters, applied electrophoretically or otherwise, have excellent resistance to salt spray, and good resistance to boiling water and solvents as well as excellent flexibility and adhesion.

Different pigments can be used with the preparations produced according to the invention. When the preparations are to be used as primers, it is advantageous to use red iron oxide pigments. Other useful pigments and additives include magnesium silicate, basic lead-silicic chromate, lead oxide, silicic acid, chromium oxide, clay, talc, thoaryte, carbon black, titanium dioxide, etc.

The following examples are given to further illustrate the invention. Parts are given by weight. The term "epoxy resin A" in the examples is used to denote the diglycidyl ether of bisphenol A at an epoxide equivalent weight of 190. "Epoxy resin B" is the reaction product of epichlorohydrin and bisphenol A using a molar ratio of 1.57 mol epichlorohydrin to 1 mol bisphenol A under application of approx. 1.8 mol of acetic acid.

Example 1

In a suitable reaction vessel equipped with a mechanical stirrer, temperature recording device, cooler and addition tube, 4753 parts of linseed oil fatty acids were introduced. The contents of the vessel were covered with nitrogen and heated to 66-107°C. 1.69 parts of sodium benzoate are then added to the reaction vessel and mixed carefully with the fatty acids by stirring for 30 minutes. 1697 parts of epoxy resin A are introduced into the reaction vessel and the temperature of the reactants is raised to 260°C. The temperature is kept at approx. 260°C while water is removed from the reaction mixture, until the acid number is reduced to 8-11. The reactants are cooled to 135°C and 879 parts of maleic anhydride are added. The reaction temperature is raised to 160—

163°C, and kept at this temperature for 1 hour, after which the temperature is raised to 182-188°C. The latter temperature is maintained until a negative permanganate test is obtained, which indicates complete conversion of the maleic anhydride. The reaction product is then cooled to 149°C and filtered.

3303 parts of the reaction product are returned to the reaction vessel and heated to 82°C.

73 parts of demineralized water and 0.4 parts of triethylamine are added and the temperature is maintained at 88

-91°C for 6.5 hours. After this heating period, the acid number is 100, which indicates practically complete hydrolysis of the anhydride groups. The temperature is then raised to 99°C and 334 parts of propylene oxide are added in the course of 6 hours and 15 minutes, the rate of addition being as follows

that a minimal reflux is obtained while the temperature is kept at 99°C. After all the propylene oxide has been added, the temperature is slowly raised to 121°C and held at this temperature for 2 hours. The viscous product formed has an acid number of 44, a bulk density of 1.03 kg/l and a Gardner-Holdt viscosity at 25°C on O-P at 60% solids in an aromatic hydrocarbon solvent (boiling range 156-203°C, KB -numbers 70-76).

A portion of the resin product is stored in a closed container for approx. 1 month at 60°C. At the end of this time, the product has an acid value of 44 and a Gardner-Holdt viscosity at 25°C of V at 60% solids in the above-described aromatic solvent. After 3 months of storage at this temperature, the acid number is 41 and the viscosity is U-V.

Another portion of the resin product is emulsified in water to 50 percent solids with 0.2 equivalents of triethylamine (1.58 parts of triethylamine per 100 parts of resin product). The resin product emulsifies easily and the emulsion formed is liquid and uniform. The emulsion is diluted to 10% solids by adding water and placed in an electrolysis cell. A steel panel whose surface is treated with zinc phosphate is placed in the cell and serves as the cell anode, while the metal container serves as the cathode. A direct current of electricity is passed through the cell for 1 minute to deposit the resin on the steel panel anode. At the deposition temperature of 27°C, the maximum voltage is 150 V. The initial current strength at this voltage is 0.5 A per 258 cm<2> surface, and the amperage after 1 minute is 0.2 A. The thickness of the film on the anode is 0.025 to 0.038 mm and the deposition ability is 100 percent. The coated steel panel is removed from the bath, rinsed with water to remove undeposited resin and fired at 182°C for 25 minutes. The film is well hardened, but somewhat wrinkled and soft.

The resin emulsion is heat-aged at 38 °C for 28 days and again subjected to the electrocoating process. At a plating temperature of 27°C, the maximum voltage is 157 V, the initial and final amperage are respectively 0.5 and 0.15 A per 258 cm<2> surface, the film thickness is 0.036 to 0.046 mm and the deposition ability is 100 percent. After firing at 182°C for 25 minutes, the film is well cured, but somewhat wrinkled and soft. The salt spray resistance of the coated panels is excellent after 240 hours of testing.

Example 2

Into a suitable reaction vessel equipped as described in Example 1, 3549 parts of the maleic acid adduct of an epoxy ester prepared as described in the first section of Example 1 are introduced. The adduct is heated to 82°C and 78 parts of mineralized water and 0.45 parts of triethylamine are added to hydrolyze the anhydride groups of the maleic acid adduct. The reactants are heated at 88-89°C for 5 hours and 10 minutes. At the end of this heating period, the acid value of the reaction mass is 100, which indicates practically complete hydrolysis of the anhydride groups. The temperature of the reactants is raised to 99°C and 251 parts of propylene oxide are added slowly over the course of 4 hours. The temperature is then slowly raised to 121°C and held at this temperature for 2 hours at which time the acid number is 56 indicating that the hydroxypropylation reaction has a density of 1.03 kg/l at 25°C and a Gardner-Holdt viscosity of 25°C on T-U at 60% solids in the aromatic hydrocarbon solvent described in Example 1. After storage in a closed container for 1 month at 60°C, the product has an acid number of 58 and a Gardner-Holdt viscosity at 60% solids in the aromatic hydrocarbon solvent of V-W. After approx. After 3 months of storage at this temperature, the acid number is 57 and the viscosity is W-X.

1845 parts of hydroxyalkylated maleic acid adduct of the epoxy ester are heated to 82°C and added over the course of 20 minutes to a solution of 216 parts of triethylamine, 270 parts of ethylene glycol monobutyl ester and 2169 parts of water, the solution being heated to 38° C. The temperature of the mixture is maintained at 91-92 °C until complete dissolution is achieved. The solution formed shows no decomposition over a longer heating period of 20 hours at , 88-93°C. The solution has a Gardner-Holdt viscosity of Z to Zt at 25°C, a specific gravity of 1.01 kg/l at 25°C, and a pH of 7.32.

Coatings are produced from the aqueous solution by spraying onto treated steel panels

with zinc phosphate. Well-cured films are obtained after 20 minutes of firing at 177°C.

An electrocoating paint is produced by first grinding in a ball mill 24.04 parts of iron oxide, 13.8 parts of talc, 18.95 parts of hydroxypropylated malenized epoxy ester, 0.76 parts of triethylamine and 42.45 parts of water until a uniform miller- <1 >dium is obtained. ,

A resin emulsion is prepared by mixing with a high-speed stirrer 32.73 parts of hydroxypropylated maleinized epoxy ester, 1.04 parts of triethylamine and 31.69 parts of water. To this in emulsion are added 34.54 parts of the painted base <: >material described above as an electrocoating paint base.

An electroplating bath is prepared by diluting the electroplating paint base to 10 percent solids content with water. This bath is then used in the electroplating process described in example 1. When 200 V is applied to the electrodes in the bath, a uniform film of 0.023-0.025 is obtained

mm thickness of the steel plate anode. For 258 cm<2> 1

anode surface, the current varies from 1.0 A at the beginning to 0.4 A at the end of 1 minute. The steel plate anode is removed from the bath, rinsed with water and burned at 177 °C for 25 minutes. The resulting coating is well cured, uniform and hard and has excellent resistance to salt spray corrosion.

Example 3

Using the same method as in example 1, 3271 parts of the maleic acid adduct of the epoxy ester described in the first section of example 1 are first reacted with 72 parts of demineralized water and 0.4 parts of triethylamine, followed by reaction with 157 parts of propylene oxide. The product obtained has a density at 25°C of 1.03 kg/l, an acid number of 72 and a Gardner-Holdt viscosity at 25°C on U-V at 60 percent solids in the aromatic hydrocarbon solvent described in example 1. After storage in a closed container for one month at 60°C, the product has a Gardner-Holdt viscosity at 25°C of V-W at 60 percent solids in the above-described aromatic hydrocarbon solvent and an acid number of 73.

The hydroxypropylated maleic epoxy ester is emulsified in water at 50% solids using 0.2 equivalents of triethylamine. After further dilution to 10% solids, the emulsion is used in the electroplating process described in example 1. At a plating temperature of 27°C, and below 125 V, a 0.025 mm thick film is deposited on the anode for 1 minute. The initial amperage is 0.6 A per 258 cm<2> coating surface and the final current strength is 0.1 A. The coated panel is removed from the bath, cleaned with water and fired at 182°C for 25 minutes. A smooth, semi-glossy, hard, well-cured coating with good salt spray resistance is obtained.

Comparable electrocoating results are obtained with epoxy ester-modified maleic anhydride preparations salted with 0.65 equivalents of triethylamine and 0.65 equivalents of triisopropylamine and emulsified in water.

Example 4

In a suitable reaction vessel equipped as described in Example 1, 2210 parts of linseed oil fatty acids are introduced. The contents of the vessel are covered with nitrogen and heated to 99°C. 0.79 part sodium benzoate is added to the vessel and thoroughly mixed with the fatty acids by stirring for 1 hour and 15 minutes. The contents of the vessel are then heated to 109°C and 790 parts of epoxy A are added. The temperature of the reactants is raised to 254°C and held at 254-260°C for 8 hours. The water from the esterification is removed as it is formed. At the end of this heating period, the acid number of the jpoxyester is 12.4, indicating practically complete esterification reaction. The epoxy ester is taken out of the tub for storage.

To a reaction vessel as described above, 2519 parts of the epoxy ester and 552 parts of maleic anhydride are added. Heat is applied to raise < the temperature to 185°C and maintained at 182-188°C 1

for 10 hours and 20 minutes. A negative permanganate test is obtained at this point, indicating practically complete adduct formation of the maleic anhydride. in

The reactants are cooled to 80°C and 0.4 parts of triethylamine and 102 parts of demineralized water are added. After heating for 8 hours at 88- < 93°C, the acid number is 145, which indicates complete hydrolysis of the anhydride groups. 327 parts of propylene oxide are then added dropwise over the course of 5 ] hours while the temperature is maintained at 88-99°C. The temperature is then slowly raised to 121°C and held at 121°C for 2 hours. The product formed has an acid value of 77.8 and a specific gravity of 1.06 kg/l.

The obtained hydroxypropylated maleic ester epoxy ester is emulsified in water to 40% solids using 0.5 equivalent of triethylamine. The emulsion is diluted to 10% solids with additional water and used in the electroplating process described in example 1. At a plating temperature of 27°C and below: 250 V, a 0.020 mm thick film is deposited for 1 minute. : The initial amperage is 1.2 A and the final amperage is . the strength is 0.1 A at 258 cm<2> coating surface. The coated plate is removed from the bath, rinsed

read with water and burn for 25 minutes at 182°C. The obtained well-cured coating is uniform,

semi-glossy and hard, and has good salt spray resistance after a 250-hour test.

Example 5

2250 parts of the maleic acid adduct of epoxy- ; the ester described in the first paragraph of exem-

pel 1 is heated to 99°C in the reaction vessel described in example 1. 150 parts of 1,2-propylenegly-

col is added within 30 minutes. After 8.5 hours of heating at 99°C, the acid number of the reaction product is 64, which indicates practically complete reaction of the glycol with the anhydride groups.

The obtained hydroxypropylated maleinized epoxy ester is emulsified with 0.5 equivalent in triethylamine to 40% solids in water. When diluting to 10% solids with additional water, the pH is 7.7. 10 percent of the solids emulsion is used

in an electroplating process as described in example 1. At a plating temperature of: 27°C under 50 V, a film of 0.020—0.023 is deposited

mm thickness of the anode for 1 minute. The initial current is 1 A and the final current is 0.2 A per 258 cm<2> surface. The coated panel is removed from the bath, rinsed with water and fired at 182°C for 25 minutes. The formed film is hard and well cured and has good salt spray resistance.

Example 6

Using the same procedure

as described in example 1, 304 parts of 1,2-propylene glycol are reacted with 3253 parts of the maleic acid adduct of the epoxy ester as described in

example 1. The product formed has an acid

figure of 57.2 and a volumetric weight of 1.034 kg/l at 25°C.

The resinous product emulsifies easily

in water to 50% solids using 0.6 equivalents of triethylamine. When diluted to 10 percent solids with additional water and used in the electrocoating process described above, results comparable to those in example 5 are obtained.

Example 7

Using the same method as described in example 1, 2033 de-

lyes linseed oil fatty acids at 260°C with 395 parts epoxy resin A and 572 parts epoxy resin B using 0.97 parts sodium benzoate as catalyst. After 10 hours at 260°C, the esterification is practically complete, the acid number being 5.4.

To 1064 parts of the epoxy ester are added 210 parts of linseed oil and 126 parts of maleic anhydride. The reactants are heated at 182°C for 9 hours until complete adduct formation is achieved. The adduct is cooled to 82°C and 40 parts water and

D.3 parts of triethylamine are added to the reaction ca-

right. After 5 hours of heating at 82-93°C

the anhydride rings are opened and the acid number is 82.

685 parts of the maleic acid adduct of the epoxy ester are heated to 99° C. and 29 parts of 1,2-butylene oxide are added slowly over the course of 4 hours. The temperature is slowly raised to 121°C and hol-

des at this temperature for 2 hours. At the end of this heating period, the acid number is 48, which indicates practically complete conversion of the butylene oxide. The reaction product is stable after 1 month of storage at 60°C.

150 parts of the epoxy ester-modified maleic acid preparation are heated to 93°C and added

tes to 335 parts water and 12 parts 2-amino-2-methyl-1-propanol heated to 38°C. Solution is obtained after heating for 1 hour at 66°C. The solution is cooled below 38°C and 50 parts of hexamethoxymethylolmelamine are added. When complete dissolution is achieved, 2 parts of the morpholine salt of p-toluenesulfonic acid are added and the solution is sprayed onto steel panels forming a 0.050 mm thick coating. After firing for 30 minutes at 177°C, well-cured films with excellent adhesion, flexibility and hardness are obtained.

Claims (2)

1. Process for the production of modified epoxy resin esters, in that A. a glycidyl ether of a divalent phenol is esterified with an unsaturated fatty acid in sufficient quantities to react with at least approx. 90 percent of the hydroxyl groups in the glycidyl ether in which one epoxide group is considered equivalent to two hydroxyl groups, and that B. the adduct of the obtained fatty acid ester with at least 8 percent by weight. maleic anhydride, calculated on the weight of the entire preparation, is formed, characterized by that C. 0.25 to 0.75 of the carboxylic acid equivalents of the maleic anhydride adduct is hydroxyalkylated with a hydroxyalkylating agent. 2 Method according to claim 1, characterized in that the hydroxyalkylation of the adduct is carried out by hydrolyzing the anhydride groups with water and reacting the free carboxyl groups with a monoepoxide containing a epoxide group on neighboring carbon atoms, preferably propylene oxide, or by reacting the adduct with an aliphatic diol, preferably 1,2-propylene glycol.