DE2602221A1 - Solid epoxide resin soln. self emulsifiable with water - as a stable dispersion suitable for coatings - Google Patents

Abstract

Solid epoxide resin soln. self emulsifiable with H2O, consists of (a) epoxide resin derivs. of formula (I) R1-O- C6H4(P)-C(R2)2-C6H4(p)-O-CH2-CR4OH-CH2-O- n right arrow C6H4(p)-C(R2)2-C6H4(p)-O-R3 (where R1 is A - is the anionic radical of a monocarboxylic acid; R6 is CH2.CH2OH or -CH2CH(OH)CH3 when R5 is H; or R6=R5=-CH2-CH2OH; or R6=R5=-CH2-CH(OH)CH3; n=1.3-13). and (b) epoxide resin derivs. of formula (V) (V is 1 but with R3 as R1). The resin epoxide equiv. is 300-2000, and the softening point (Durrans)=50-125 degrees C. Self emulsifiable solid resin mixts. are obtd. which form a stable aq. dispersion to which may be added crosslinking agents and other additives. The mixt. is used as a binder in coating materials.

Description

Solid epoxy resin solution that can be self-emulsified with water

Process for the manufacture and use of the same On the varnish resin and the coating sector has increased the use of polyglycidyl ethers because of the Proven excellent technological properties. Special fields of application are with the use of higher molecular weight polyglycidyl ethers with softening points between 5000 and 125 ° C and epoxy equivalents from 300 to'2000 in particular the coating sector.

The crosslinking of the epoxy resins used in the coatings sector either in the form of powders or solutions in organic solvents n.zit carboxylic acid anhydrides or with dicyandiamide, with predominantly the Epoxy groups of the polyglycidyl ether react, but the crosslinking can also be achieved by means of Phenolic or melamine resins, which in a mixture with the polyglycidyl ether to 10 - 6C «, preferably 20-40% are present, in the heat to hardened coatings, mainly those in the. higher molecular weight polyglycidyl ethers present ON groups react.

Such systems of the last-mentioned type are mainly used the areas of container coating.

The disadvantage of powder coating is, besides the indisputable Advantages, Above all, to mention the bad flow, also with the well-known flow aids cannot be improved in such a way that the surface of the film comes close to one that can be achieved with lacquer films from systems containing solvents Disadvantages are the high investment costs for powder production and powder coating systems and the low flexibility in the choice of layer thicknesses; those under 70 - 75 pm are hardly achievable.

For these and other reasons, the coating is made more solvent-based Systems remain indispensable for many areas of application. However, there are disadvantages the high environmental pollution caused by evaporating solvents and the mostly required eau of costly afterburners and the effective ones Loss of solvent is a crucial point in a cost analysis For reasons of occupational hygiene, the use of solvent-based products is prohibited Systems complete in many cases.

The object of the present invention was therefore to provide polyglycidyl ethers, the softening points between 500C and 12500 and epoxy equivalent weights of 300 to 2000 to be modified in such a way that they can be used alone or together with their Crosslinking agents such. B. dicyandiamide, phenolic resin and / or melamine resin in one aqueous dispersion can be converted and thereby as self-emulsifiable with water solid epoxy resin solution.

So far, dispersions of different polymers in water have been possible but such dispersions have proven to be very unstable. Took place within a short period of time ranging from a few hours to a few days a settling. The polymer dispersions known hitherto also have poor ones film-forming properties, which are mainly due to the large particle sizes of the Resin can be attributed, which so far in the order of 50 microns and above lay.

In DT-OS 1.921 198, dispersions and processes are related to it Production described, the resin phase of which can also consist of epoxy resin here with the aid of a colloid mill using quaternary ammonium salts as cationic foreign emulsifiers produced a dispersion, the particles of which have a have an average diameter of 1 - 5 µm. Apart from that through the use a colloid mill, the particle diameter is still very complex great.

Process for the production of stable aqueous epoxy resin emulsions, which are completely solvent-free are z. B.

also known from DT-OS 2 332 165. Here, however, the resin phase a liquid epoxy resin that emulsifies using nonionic emulsifiers Liquid epoxy resins are because of their low degree of condensation for many unsuitable applications that result in the use of nonionic emulsifiers in the case of polyglycidyl ethers with a higher degree of condensation, especially those which are used in Room temperature are fixed, not to success.

U.S. Patent No. 3,707,526 states that water-soluble coating materials can be prepared by conventional, water-insoluble epoxy compounds, such as z. B.

Diglycidyl ether of bisphenol A, with dimethylolpropionic acid, optionally in the presence of other carboxylic acids.

The process leaves some to be desired, as the respondents need to be heated for several hours in order to produce the product with amines, such as B.

Alkanolamines, which make it water-soluble.

The extended heating time required for the preparation of the above mentioned product is required is not only for a commercial process inexpedient, but undesirable for other reasons, as this is a spontaneous, exothermic polymerization of the epoxy compound can occur, whereby an infusible, insoluble and crosslinked plastic is obtained that does not can be used as a coating material. Also, on epoxy groups related, a large molar excess of acid (epoxy groups acid = 1: 2 - 3) used what is undesirable.

Resins are known from US Pat. No. 3,336,253 which are made in water can be and the reaction products of yono or dialkanolamines with different are water-insoluble polymers, in particular with epoxy polymers, which Contain end groups that are reactive with amines. The resulting products will be water-soluble following the neutralization of the alkanolamine residue with an acid made.

The preferred reaction products contain one epoxy radical per molecule and are applied as coverings to various substrates. The toppings are then crosslinked by self-polymerization. A disadvantage of this covering is aterialien is the presence of epoxy radicals, which in the presence of traces of acidic or basic materials, such as. B. the alkanolamine residues at one end of a each molecule are present, can enter into a self-polymerization, whereby cross-linked infusible materials are obtained. This increases the shelf life of the Coating compositions greatly reduced. In the aforementioned U.S. Pat 3,336,253 indicates that the storage stability of the epoxide / alkanolamine reaction products can be increased by including all unreacted epoxy groups Use of different compounds, such as B. of dialkanolamines eliminated. This way of working is undesirable because it leaves all reactive sites for the subsequent Networking is eliminated, which leads to the production of a permanent, solvent-resistant Topping are required.

In addition, these products can only be produced in very large quantities of dialkanolamines (in the aforementioned US Pat. No. 3,336,253, for example, up to 28% diethanolamine used). The coatings obtained are opposite to aqueous media so unstable that they are completely useless in many cases. In US Pat. No. 3,336,253 there is no information that the reaction products described there could be used to emulsify epoxy resins. Even those according to the DT-OS 2,415,100 manufactured products contain stoichiometric amounts of alkanolamines based on epoxy resin. In DT-OS 2 426 996, the amine amounts were reduced to approx. 5%, but the dispersions still contain significant amounts of solvent. The mentioned method is also not suitable for preparing solvent-free dispersions.

Another object of the present invention was to provide self-emulsifiable Solid epoxy resin mixtures in which the component with the formula V has melting points between Contains 50 0C and 125 0C and epoxy equivalent weights from 300 to 2000 in an aqueous stable dispersion, if necessary together with crosslinkers and others for one certain application required additives, z. B. elasticizing agents to bring, the aliphatic OH groups and / or the epoxy groups for crosslinking should be available.

The invention relates to a solid epoxy resin solution which is self-emulsifiable with water and which is composed of epoxy resins of the formula I. where R "is the remainder R2 and, 4 H and / or CH3 and R3 the remainder where A e is the anionic radical of a monocarboxylic acid and R5 and R6 have the following meaning 6 If R5 is the radical below then R6 is the radical below is radical H -CH2CH2OH -CH2CH (OH) 0H3 -CH2CH2OH -CH2-CH2OH CH2- CH (OH) CH3 -CH2-CH (OH) CH3 and n means values from 1.3 to 13.

and solid epoxy resins of the formula V where R4 and R² are H and / or CH3 and n has a value of 1.3 to 13, the resins have epoxy equivalent weights of 300 to 2000 and the Durrans softening points are between 50 and 125 ° C.

The invention also relates to a solid epoxy resin solution which is self-emulsifiable with water and which consists of epoxy resins of the formula I and epoxy resins of the formula V, characterized in that the mixture of the formula I ', R1, R², R3, R4, R5, R6 and A # in which R, R, R², R, R, R,, R3, n and A # have the meaning already mentioned and where the sum of n1 and n3 has the value 2 and that The ratio of n1: n3 has values from 20 to 0.1, preferably from 10 to 0.1.

The invention also relates to a process for producing the above-described epoxy resin mixture which is self-emulsifiable with water, characterized in that a) solid epoxy resins of the general formula V where R 4 and R2 are H and / or CH3 and n 3 has a value of 1.3 to 13, the resins have epoxy equivalent weights of 300 to 2000 and the softening points according to Durrans are between 50 and 12500, in the presence of at least one inert organic solvent a boiling point between 50 and 170 ° C with 0.01 to 1.0 mol (based on 100 g of solid epoxy resin with the formula V) alkanol or dialkanolamine with the formula VI in which R5 and R6 have the same meaning as in formula I, are reacted at 50 to 1000C with thorough stirring b) and the reaction product obtained with 0.01 to 1.0 ol of a monocarboxylic acid (based on 100 g of solid epoxy resin with the formula V) with a pka value of 2 to 5 added, the equivalent ratio of monocarboxylic acid to alkanol or dialkanolamine must be 0.7: 1 to 3: 1.

Another object of the invention is the use of the described Mixtures of epoxy resin solutions as binders in aqueous coating agents.

The production of self-emulsifiable epoxy resin mixtures can thereby take place. that one is present in a solvent (mixture) Epoxy resin V with stirring with 0.01 to 1.0, preferably 0.02 to 0.1 mol of alkanolamine VI, based on 100 g of epoxy resin V, preferably dialkanolamine, most preferably Diethanolamine, at 50 to 100 ° C, preferably at 70 to 9000, within 10 to 180 *, preferably from 15 to 60 minutes postponed, after completion the post-reaction time of about 10 to 180, preferably 30 to 60 minutes, at 30 to 9000, preferably at 50 to 700C 0.01 to 1.0, preferably 0.02 to 0.1 mol of a monocarboxylic acid based on 100 g of epoxy resin, the equivalent ratio Monocarboxylic acid amine = 0.7: 1 to 3: 1, preferably 1.2: 1 to 1.4: 1 should be added within 10 to 180 minutes3, preferably from 40 to 80 minutes, formic acid, more preferably lactic acid, being used as the monocarboxylic acid. If the mixture of epoxy resin I and V is desired as a dispersion, the Mix with the desired amount of water while stirring vigorously at 20 to 700C, preferably added at 35 to 450C and finally that contained in the mixture Solvent azeotropically with water in vacuo at 30 to 60 ° C, preferably at 35 up to 450C, if necessary distilled off under cycle conditions.

But it is also possible to convert the solid epoxy resins of the formula I of the epoxy resins with the formula V with the alkanolamine or dialkanolamine of the formula VI in a stoichiometric ratio of 2 epoxy groups to 1 amine group, if appropriate in the presence of inert organic solvents.

As a solvent in which the epoxy resins V at 50 to 10000 in dissolved form should be present before the amine addition VI are suitable — depending on the type of epoxy resin z. B. all lower boiling alcohols from ethanol to butanol, mixtures of alkanol / toluene, Alkanolixylene up to approx. 30% toluene or xylene content, as well as the various lower boiling ketones e.g. B.

Acetone, methyl ethyl ketone and kIethylisobutylkc-ton.

Suitable epoxy resins V which can be used according to the invention are based on diphenylolpropane (bisphenol A) and / or diphenylolmethane (Bisphenol F) and epihalohydrin and / or, methylepihalohydrin, preferably epichlorohydrin according to the method described in the literature (see e.g.

"Epoxy compounds and epoxy resins" Paquin (1958), p.322 et seq where R4 and R² are H and / or CH3 and n has a value of 1.3 to 13, the resins have epoxy equivalent weights of 300 to 2000 and the Durrans softening points are between 50 and 125.degree.

As inventively usable alkanolamines or dialkamolamines are z. B. all of the general formula VI corresponding suitable wherein R5 and R6 have the same meaning as In Formula 1.

Monocarboxylic acids which can be used according to the invention are general such can be used whose pka value is in a range from 2 to 5, such as. B. formic acid, Lactic acid and dimethylol propionic acid.

Example 1 291 g of an epoxy resin of the general formula were obtained where n has the value 9.7 to 13.0, with a softening point according to Durrans of 11800 and an epoxy equivalent weight of 1865 (one such epoxy resin is from Hoechst AG with the designation EP 307 in the technical data sheets Epoxy resins described) melted. At 1300C they became the melt within 36 g of toluene and 108 g of n-butanol were added over a period of 1 hour, the temperature gradually increasing fell to 800C. Then 9 g (0.03 mol / 100 g EP resin) diethanolamine added. The reaction was allowed to continue for one hour at 80.degree. C., then 7.2 g of a 99% strength by weight formic acid were added at 70 ° C. in the course of 1 hour. The mixture was cooled to 40 ° C. and 500 g of distilled water were added over the course of 1 hour Stir in water. Finally, the solvent mixture was azeotroped with water at 40 ° C. in vacuo removed by distillation. The resulting dispersion was filtered through a 56 µm mesh.

Characteristic values: Solids: 44.1% Viscosity at 1720 mPas 25 ° C: (Brookfield, Spindle 3/30 U) +) pH value: 3.18 D. The composition of the resin content of the dispersion is represented by formula I ', where R1 and R3 have the same meaning as in Formula I 'have, R2 and R4 mean H, R5 and R6 mean the radical -CH2-CH2-OH, A e denotes the radical HCOO #, n has a value from 9.7 to 13.0 and n1: n3 a Has a value of 0.5 to 0.7.

u U = revolutions / min.

Example 2 291 g of an epoxy resin of the general formula were obtained V, where n is 9.7 to 13.0, with a Durrans softening point of 1180C and an epoxy equivalent weight of 1865 (one such epoxy resin is from Hoechst AG with the designation EP 307 in the technical data sheets "Epoxy resins" described) melted. At 130 ° C were to the melt within 1 hour 36 g of toluene and 108 g of n-butanol were added, the temperature gradually increasing fell to 800C. Then 9 g (0.03 mol / 100 g EP resin) diethanolamine added. The reaction was allowed to continue for one hour at 80.degree. C., then 23.9 g of a 90% strength by weight lactic acid were added at 70 ° C. within 1 hour The mixture was cooled to 40 ° C. and 450 g of distilled water were added over the course of 1 hour Stir in water. Finally, the solvent mixture was azeotroped with water at 40 ° C. in vacuo removed by distillation. The dispersion obtained was filtered through a 56 μm net.

Characteristic values: Solids: 42.5% viscosity at 1800 mPas 25 C: (Brookfield, Spindle 3/30 U) pH value: 3.25 The composition of the resin part of the dispersion is represented by formula I ', where R1 and R3 have the same meaning as in Formula I ', R2 and R4 mean H5 R5 and R6 mean the radical -CH2-CH2-OH, AG denotes the radical CH3-CH (OH) -COO #, n has a value from 9.7 to 13.0 and n1: n3 has a value from 0.5 to 0.7.

Example 3 291 g of an epoxy resin of the general formula were obtained V, where n is 1.9 to 2.5, with a Durrans softening point of 70 0C and an epoxy equivalent weight of 4/0 (such an epoxy resin is from Hoechst AC with the designation EP 301 in the technical data sheets "Epoxy Resins" described) melted. At 130 ° C 36 g of toluene and 108 g of n-butanol were added to the melt in the course of 1 hour the temperature gradually fell to 80 ° C. Subsequently, within 15 minutes 9 g (0.03 mol / 100 g EP resin) diethanolamine was added. It was left at 80 ° C. for one hour post-react, then 18.3 g of a 90% strength by weight were obtained at 70 ° C. within 1 hour Lactic acid added.

The mixture was cooled to 40 ° C and it was within 1 hour Stir in 500 g of distilled water. Finally, azeotrope took place in vacuo at 40.degree the solvent mixture is removed by distillation with water. The dispersion obtained was filtered through a 56 µm mesh.

Characteristic values: Solids: 60.1% viscosity at 2290 mPas 25 C: (Brookfield, Spindle 3/30 U) pH value: 3.48 The composition of the resin part of the dispersion is represented by formula I ', wherein R and R have the same meaning as in formula I ', R2 and R4 denote H, R5 and R6 denote the radical -CH2-CH2-OH, A # denotes The radical CH3-CH (OH) COO # denotes, n has a value from 1.9 to 2.5 and n: n3 is a Has a value of 5 to 6.

Claims (5)

Claims 1. With water self-emulsifiable solid epoxy resin solution, which is made from epoxy resin derivatives of the formula I where R1 is the remainder R2 and R4 H and Z or CH3 and R3 the remainder where Ag represents the anionic radical of a monocarboxylic acid and R5 and R6 have the following meaning if R5 is the radical below then R6 is the radical below is H -CH2CH2OH H -CH2CH (OH) CH3 -CH2CH2OH -CH2-CH2OH -CH2-CH ( OH) CH3 -CH2-CH (OH) CH3 and epoxy resins of the formula V where R and R2 are H and / or CH3 and n has a value of 1.3 to 13, the resins have epoxy equivalent weights of 300 to 2000 and the Durrans softening points are between 50 and 125 G. 2. Self-emulsifiable solid epoxy resin solution according to claim 1, characterized in that the mixture of formula I ' wherein R1, R², R3, R4, R5, R6, n and A # have the meaning already mentioned. and where the sum of n1 and n3 has the value 2 and the ratio of n1: n3 has values from 20 to 0.1, preferably from 10 to 0.1. 3. A process for the preparation of the self-emulsifiable solid epoxy resin solutions mentioned in claim 2, characterized in that a) solid epoxy resins of the general formula V wherein R4 and R² are H and / or CH3 and n has a value of 1.3 to 13, the resins have epoxy equivalent weights of 300 to 2000 and the softening points according to Durrans are between 50 and 1250, in the presence of at least one inert organic solvent with a Boiling point between 50 and 170ob with 0.01 to 1.0 mol (based on 100 g of solid epoxy resin with the formula V) alkanol or dialkanolamine with the formula VI in which R5 and R6 have the same meaning as in formula I, are reacted at 50 to 1000C with thorough stirring, b) and the reaction product obtained with 0.01 to 1.0 mol of a monocarboxylic acid (based on 100 g of solid epoxy resin with the formula V ) with a pka value of 2 to 5, whereby the equivalent ratio of monocarboxylic acid to alkanol or dialkanolamine must be 0.7: 1 to 3: 1. 4. Solid epoxy resin solution according to claim 1 or 2 dispersed in the aqueous Medium. 5.Use of the mixtures mentioned in claims 1, 2 and 4 as Binder in aqueous coating agents.