DE4423309A1 - Process for the preparation of a sterically stabilized, non-aqueous dispersion of a polyepoxide and coating compositions containing this dispersion - Google Patents

Abstract

The invention concerns a method of producing a sterically stabilized non-aqueous dispersion of a polyepoxide, the method calling for at least one epoxy resin (A) with at least two epoxy groups to be reacted, in an organic solvent in the presence of a dispersion stabilizer, with at least one diol (B) of the formula (I) HOROH, in which R is a group of the formula (II) in which D is a methylene or propylene group, and optionally with an additional component (C) having groups which are reactive towards epoxy or hydroxyl groups. The method is characterized in that 1) in a first stage, part of the epoxy resin (A) is reacted with an excess, relative to the amount of epoxy resin used in this stage (1), of the diol (B) of formula (I) and, optionally, of the additional component (C) and 2) the reaction product obtained in stage 1 is subsequently reacted with the remainder of the epoxy resin (A) and/or of the additional component (C) to give the required end product.

Description

The subject of the present application is a method to produce a sterically stabilized, not aqueous dispersion of a polyepoxide, in which in a organic solvents in the presence of a dispersion stabilizer with at least one epoxy resin (A) tel at least 2 epoxy groups per molecule with min at least one diol (B) of the formula (I)

HOROH (I)

in which R is a group of the formula (II)

where D is a methylene or a propylene group is, and optionally with a further component (C), the groups reactive towards epoxy or hydroxyl groups has, is implemented.

The present invention also relates to the non-aqueous dispersers made by this process sions and the use of these dispersions in Coating agents, in particular for coating of packaging.

EP-A-321 088 describes a process for the production a sterically stabilized, non-aqueous dispersion a polyepoxide according to the preamble of claim 1 known. The only disadvantage of this method is  limits possible production of dispersions with a defined structure. In need of improvement This procedure is the incorporation of others Resins. Finally there are also different mecha properties of the resulting coatings in need of improvement.

The present invention is therefore the object based on a method of making a steric stabilized, non-aqueous dispersion of a poly to provide epoxides where the result dispersions have a defined structure. Furthermore, the dispersions should be easy to incorporate capacity / carrying capacity for one or more other resins exhibit. The resulting disper sions when used as a coating agent for the Interior painting of cans attached to this coating medium usually placed requirements, e.g. B. good adhesion and good flexibility, good ste Resistance to corrosion and no pores in the resul coating and good application properties properties of the coating agent. About that In addition, the process should be simple and inexpensive be feasible.

This task is surprisingly achieved by a ver driving of the type mentioned solved that is marked that

• 1. in a first stage at least part of the Epoxy resin component (A) with an excess of Diols (B) of formula (I) and optionally the component (C), based on the amount used in step (1) Epoxy resin (A), is implemented and  
• 2. then the reaction obtained in step (1) product with the remaining epoxy resin component (A) and / or component (C) to the desired end product is implemented.

The present invention also relates to non-aqueous dis persions and the use of these dispersions in Coating agents, in particular for coating of packaging.

The inventive method has the surprising Advantage of the fact that additional Har zen in the dispersions is improved. Advantageous is further that with the inventive method Dispersions of resins with a defined structure be preserved. Flexi are also being improved stability, liability and resistance to sterilization of the resulting coatings. After all, it is from Advantage that the resulting dispersions at Ver used in coating materials for interior painting of cans commonly used on this coating tel requirements, z. B. good application properties of the coating compositions.

In the following, the first in the invention compounds used in accordance with the method explained.

To produce the non-aqueous dispersion of the poly epoxides become diols (B) of the formula (I)

HOROH (I),

used in which R is a group of the formula (II)

where D is a methylene or a propylene group is.

Preferred diol (B) of the formula (I) is bisphenol A used.

For the production of the nonaqueous Dispersion of the polyepoxide-suitable epoxy resins (A) are especially for stage (1) of the process Epoxies with an average of at least 2 epoxy groups per Molecule. Epoxy is preferred as component (A) resins are used that are liquid at room temperature. Epoxy resins with a Epoxide equivalent weight from 150 to 450, preferably from 170 to 192.

Are for use in the method according to the invention especially aromatic epoxy resins (A), but also also aliphatic and araliphatic epoxy resins (A) suitable. Examples include diglycidyl ethers from Poly phenols, diglycidyl ethers of dialcohols and diglyci called dylester of dicarboxylic acids. To be favoured Diglycidyl ethers of polyphenols, especially diglyci bisphenol A dylether, and epoxidized novolak resins, epoxy resins based on bisphenol are particularly preferred A, used. Of course, Gemi different epoxy resins are used. Furthermore, it is of course also possible in the Stage (1) and stage (2) of the Ver different epoxy resins (A). In particular, it is possible in stage (2) of inventive method also epoxy resins (A) with  a functionality <2, for example also Monoepoxides to use.

Suitable epoxy resins (A) are, for example, the products based on bisphenol A which are commercially available under the following names:
Epikote® 828 from Shell-Chemie;
DER® 330 and 333 from Dow Chemicals;
GY 250 from Ciba-Geigy.

Also suitable, for example, are the products commercially available under the following names based on epoxidized novolak resins:
XPY 307 and EPN 1139 from Ciba-Geigy and DEN® 438 from Dow Chemicals.

Also suitable are those in EP-A-321 088 page 2, line 46, to page 5, line 36, and in Karsten, paint raw material tables, 9th edition, capital 31, Sections 31.1 and 31.2, described epoxy compound fertilize.

Possibly. can be small amounts, preferably less than 20 % By weight, particularly preferably from 1 to 15% by weight, of the Diols (B) and / or the epoxy resin component (A) by other components (C) to be replaced with the Epoxy resin component (A) or with the in step (1) of Process obtained reaction product implemented will. In particular, as component (C) difunk tional connections used. By using it of these further compounds (C) can be targeted physical properties of the resulting poly epoxy resins can be improved.

For example, as component (C) for the Implementation with the epoxy resin small amounts of adipic acid  or dimer fatty acid or other flexibilizing com poneneten be installed. You can also do this Polyester, polyacrylates, diamines and fatty acid amides be used. Component (C) is preferred in stage (1) of the method implemented.

The reaction of the diol (B) of the formula (I) and, if appropriate, the Component (C) with the epoxy resin component (A) in the presence of a steric dispersion stabilizer.

A steric dispersion stabilizer is a verb with a part that corresponds to the part to be stabilized Associated with epoxy resin (usually as anchor components called te), and a part containing the solvent associated (usually as a solvated component designated).

Suitable steric dispersion stabilizers are known and for example in EP-A-321 088 Page 5, line 41, to page 6, line 1, and in K.E.J. Barrett, Dispersion Polymerization in Organic Media, John Wiley and Sons, 1975.

For example, in the method according to the invention Ren dispersion stabilizers are used in which the anchor component on an acrylate polymer based. Suitable acrylate polymers are homo- and Copolymers of (meth) acrylic acid alkyl esters (e.g. Polymethyl methacrylate, polyethyl methacrylate, polymethyl acrylate, polyethylacrylate, polyethylacrylate / polyethyl methacrylate u. a.) and copolymers of (meth) acrylic acid alkyl esters and methacrylic and / or acrylic acid, the proportion of polymerized (meth) acrylic acid is usually below 10% by weight. Furthermore, in the copolymers still have small proportions of other ethyls polymerized nisch unsaturated monomers,  for example small amounts of crotonic acid, isocroton acid, maleic acid and / or alkyl esters of these acids.

The solvated component can be a poly-C6-18 alkyl ester, such as B. Poly-2-ethylhexyl acrylate Polyester such as B. poly-12-hydroxystearic acid, or a polymer, such as. B. derived from polybutadiene Resins, be.

The dispersion stabilizers can according to the usual wisely applied methods can be produced by for example the reaction product of poly-12-hy droxystearic acid with glycidyl (meth) acrylate with the desired acrylate monomers is copolymerized or by, for example, the one desired as the anchor component Polymer with the as a solvated component desired polymer (e.g. derived from polybutadiene tet) is implemented.

In the method according to the invention, in particular Solvent used, the resulting polyepoxide do not dissolve, for example non-polar organic solvents medium. Aliphatic solvents are preferred Hydrocarbons used, possibly up to 20 % By weight of other solvents, e.g. B. aromatic kohlwas ser substances, such as B. xylene and Solvesso® 150 included can.

High-boiling aliphati are preferred as solvents cal hydrocarbons, especially those with a Boiling point between 120 and 280 ° C, used. At games for suitable solvents are Hydrosol® P 2300 EA from Deutsche Hydrocarbures GmbH, Exxold® 240-270, Norpar® 12 and Isopar® M from Deutsche Exxon Chemical GmbH.  

The amount of solvent is preferably chosen so that the reaction of the diol (B) with the epoxy resin components te (A) (stage (1)) for a dispersion solid holds from 20 to 80% by weight, preferably from 50 to 70 Wt .-% and the implementation of the reaction product Step (1) with the diol (B) (step (2)) on a Disper sion solids content of 25 to 85 wt .-%, preferred from 55 to 75% by weight.

The reaction of the diol (B) with the epoxy resin components te (A) is preferably carried out in the presence of a catalyst tors. Suitable catalysts are, for example Alkali metal carbonates, such as potassium and sodium carbonate, Alkali metal hydroxides such as sodium and potassium hydroxide quaternary ammonium salts, amines, such as dibenzylamine, and trialkylphosphonium salts, such as. B. triphenyl ethylphosphonium iodide and triphenylethylphosphoniumace did. Triphenylethylphos is preferred as the catalyst Phonium iodide used.

The manufactured with the inventive method Reaction products (in this application regardless of the actual functional groups always as Usually referred to as polyepoxy resin) Equivalent weight of functional groups from 678 to infinite, preferably from more than 1000. Is in the second stage of the process is the reaction product the first stage exclusively or predominantly with implemented a diepoxide (A), so with the Polyepoxide produced according to the inventive method resin epoxy groups as functional groups (Epoxy equivalent weight is given). Will that Reaction product of the first stage, however, in the second stage with a monoepoxide and / or the Implemented component (C), there is the equivalentge  emphasizes the content of functional groups that are caused by these components are introduced into the resin.

It is essential to the invention that the implementation of the Epoxy resin component (A) with the diol (B) of the formula (I) takes place in a two-stage process.

In the first stage of the method according to the invention is first part of the epoxy resin component (A) an excess of at least one diol (B) of the formula (I) and optionally component (C), based on the in this stage (1) of the method used amount of Epoxy resin component (A) implemented. Here is a obtained essentially phenoxy-terminated product. The amounts of epoxy resin component (A) and diol (B) Formula (I) are preferably chosen so that 1 mol Epoxy resin component with 3 to 1.001 mol, preferably 1.5 up to 1.02 mol, at least one diol (B) becomes.

The reaction of the epoxy resin component (A) with the the diols (B) and optionally (C) in the first stage of The method according to the invention is preferably carried out by that that or the epoxy resins, that or the diols and optionally (C), the dispersion stabilizer and the dissolver tel together and slowly warmed while stirring will. Preference is given to temperatures between 80 and Heated to 140 ° C. At this slightly elevated temperature is preferably dispersed for some time. After that If necessary, the catalyst is added and on the desired reaction temperature heated. The order settlement of the epoxy resin with the diol and possibly (C) usually takes place at a temperature between rule 120 and 250 ° C, preferably at a temperature between 160 and 180 ° C.  

In addition, it is in the first stage of the invention according to the method also possible, first the epoxy resin component (A) with the solvent and the disperser tion stabilizer and by stirring and if necessary gentle heating, preferably to temperatures between 80 and 140 ° C to disperse the epoxy resin component. The dispersion can then be adjusted to the desired one Heated reaction temperature and the diol (B) and possibly (C) can be added.

The reaction of the epoxy resin component is preferred (A) with the diol (s) (B) in the first stage of Procedure continued until the resulting Reaction product a phenoxy equivalent weight of min at least 256, preferably of at least 682 and particularly preferably of at most 20,000.

In a second stage, that in stage (1) phenoxy-terminated reaction product obtained with the remaining epoxy resin component (A) and / or possibly white teren modifying components to the desired Final product implemented. Preference is given to the second Stage the product obtained in stage (1) with the rest Lichen epoxy resin component (A) implemented.

The reaction with the rest of the epoxy resin component and / or possibly further modifying components (C) preferably takes place in that the epoxy resin and possibly the other modifying components in a he high temperature, preferably at a temperature of 60 to 120 ° C, slowly added dropwise. Furthermore, it is possible, the remaining epoxy resin component in the stu admit fe 2 of the procedure at once. Prefers after the end of the epoxy resin addition or addition of the modifying components again catalyst given and the temperature increased, preferably to values  between 160 and 180 ° C. Then the reaction continues continued until the desired degree of implementation is achieved is.

In addition, it is also possible to use the remaining epoxy resin component and / or the other modifying Components (C) at room temperature to that in step (1) of the process obtained phenoxy-terminated product to give, then to a temperature of 120 to 180 ° C. heat up, disperse and the reaction as long continue until the desired degree of implementation is reached.

Those produced by the process according to the invention Dispersions of polyepoxy resins are particularly suitable for use in coating materials. These In addition to these non-aqueous, sterically stabilized dispersions still further bin detergent, other common solvents, possibly other Resins, possibly pigments and / or fillers as well as usual ones Auxiliaries and additives contained in usual amounts.

The coating compositions preferably contain up to 100 % By weight, particularly preferably 60 to 100% by weight, of the non-aqueous dispersion, 0 to 40 wt .-% further bin medium, 0 to 40% by weight of other resins, 30 to 80 % By weight of solvent (including the solvent content the non-aqueous dispersion), 0 to 50 wt .-% pigments and / or fillers and 0 to 10% by weight customary Auxiliaries and additives, each based on the Total weight of the coating agent.

The coating compositions are preferably used for Coating of packaging, especially for coating processing of food packaging. The Packaging can come from a wide variety  Materials exist and a wide variety of geometries exhibit. Black in particular comes as materials sheet, tinplate and various iron alloys in Question that may have a passivation layer on it Base of nickel, chrome and zinc compounds are. The packaging can be in the form of, for example Half can parts, i.e. hulls and lids, as 3 parts cans and as 2-part, deep-drawn or other deep-drawn cans, such as. B. drink ke- and food cans can be coated.

The coating compositions according to the invention harden in Ob temperature range from 150 to 400 ° C during a Time from 2 s to 15 min. You can by rolling, Squeegee, brush, spray, flood or dive with be applied by conventional devices, wherein the film then becomes an adherent coating is cured. The coating compositions are before applied by roller application.

The invention is now based on exemplary embodiments explained in more detail. All information about parts and percentages are weights, unless expressly stated something else is found.

Production of a dispersion stabilizer

In the inlet 1
18.774 parts of methyl methacrylate and
1.198 parts methacrylic acid
weighed in and mixed.

In the inlet 2
0.533 parts of dibenzoyl peroxide (75% in water) and
9.910 parts of xylene
weighed in and mixed.

Then be
29.724 parts of xylene
19.974 parts of a commercially available, solvent-free polymer based on butadiene with a number average molecular weight of approx. 5000, with 15-20% vinyl double bonds, 50-60% 1,4-trans double bonds, 25-35% 1,4- cis double bonds and an iodine number of approx. 450 (commercial product Lithene N4-5000 from Chemetall GmbH, Frankfurt)
19.794 parts of a commercially available mixture of paraffinic and naphthenic hydrocarbons in the range C15-C17 with a boiling range between 230 and 265 ° C (commercial product Hydrosol P 230 EA from Deutsche Hydrocarbures GmbH)
mixed and heated to 123 ° C with stirring. Then feed 1 and feed 2 are metered in simultaneously but separately within 1.5 h. Then be
0.093 parts of tert-butyl per-2-ethylhexanoate
added and the temperature kept at 123 ° C for 1 h. Then 9.910 parts of solvent are distilled off under a slight vacuum. Then 9.910 parts of a commercially available mixture of paraffinic and naphthenic hydrocarbons in the range C15-C17 with a boiling range between 230 and 265 ° C (commercial product Hydrosol P 230 EA from Deutsche Hydrocarbures GmbH) with stirring within 30 min at a temperature of 122 -124 ° C added dropwise. Then it is cooled.

The dispersion stabilizer solution thus obtained has a solids content (60 min 130 ° C) of 38.5%, an acid number of 21 mgKOH / g and a viscosity of 2.2 ± 0.2 dPa.s (ICI plate / cone viscometer, 23 ° C) on.

example 1

28.172 parts of a commercially available liquid epoxy resin based on bisphenol A with an epoxide equivalent weight of 188 and a molecular weight of 350-380 (commercial product Epikote® 880 from Shell Chemie)
0.455 parts of a commercial liquid epoxy resin based on bisphenol A with an epoxide equivalent weight of 188 and a molecular weight of 350-380 (commercial product Epikote® 880 from Shell Chemie)
20,526 parts of bisphenol A
14.964 parts of the above-described dispersion stabilizer and
27.389 parts of a commercially available mixture of paraffinic and naphthenic hydrocarbons in the range C15-C17 with a boiling range between 230 and 265 ° C (commercial product Hydrosol P 230 EA from Deutsche Hydrocarbures GmbH)
are mixed and heated to 120 ° C. with slow stirring (approx. 80 revolutions per minute). Then the stirrer speed is increased to 300 revolutions per minute and dispersed for 1 hour. Then be
0.018 parts of phosphonium ethyl triphenyl iodide as a catalyst
added and the temperature increased to 170 ° C. It is kept at this temperature until the phenoxy equivalent weight is 1990. Then it is cooled to 120 ° C and it will be
8.464 parts of a commercial liquid epoxy resin based on bisphenol A with an epoxide equivalent weight of 188 and a molecular weight of 350-380 (commercial product Epikote® 880 from Shell Chemie), heated to 80 to 120 ° C.
added dropwise within 1 h (stage II). The mixture is then dispersed for one hour. Then be
0.012 parts of phosphonium ethyl triphenyl iodide as a catalyst
added and the dispersion is heated to 170 ° C. The temperature is maintained until the desired epoxide equivalent weight of 3800 g / mol is reached. It is then cooled and the product is filtered through a nylon mesh (mesh size 30 μm).

The dispersion obtained has a solids content (90 min 180 ° C) of 63.5% and a viscosity (ICI Plate / cone viscometer, 23 ° C) of 2.9 dPa · s. The The polyepoxide obtained has a number-average molecule  Lar weight of 11 375, a weight average molecular weight of 78 069 and a non-uniformity of 6.9 on (each determined by gel permeation chromatography against polystyrene standard). The dispersion thus obtained has a storage stability of more than 30 at 23 ° C Days on.

Comparative Example 1

37.683 parts of a commercial liquid epoxy resin based on bisphenol A with an epoxide equivalent weight of 188 and a molecular weight of 350-380 (commercial product Epikote® 880 from Shell Chemie)
0.393 parts of a commercial liquid epoxy resin based on bisphenol A with an epoxide equivalent weight of 188 and a molecular weight of 350-380 (commercial product Epikote® 880 from Shell Chemie)
20.904 parts of bisphenol A
14.782 parts of the dispersion stabilizer described above,
0.119 parts of phosphonium ethyl triphenyl iodide as catalyst and
18.977 parts of a commercially available mixture of paraffinic and naphthenic hydrocarbons in the range C15-C17 with a boiling range between 230 and 265 ° C (commercial product Hydrosol P 230 EA from Deutsche Hydrocarbures GmbH)
are mixed and heated to 120 ° C. with slow stirring (approx. 80 revolutions per minute). Then the stirrer speed is increased to 300 revolutions per minute and dispersed for 1 hour. Then the temperature is increased to 170 ° C. It is kept at this temperature until the epoxy equivalent weight is 3800. Then it is cooled to 160 ° C and it will be
7.142 parts of a commercially available mixture of paraffinic and naphthenic hydrocarbons in the range C15-C17 with a boiling range between 230 and 265 ° C (commercial product Hydrosol P 230 EA from Deutsche Hydrocarbures GmbH)
added dropwise within 30 min. It is then cooled and the product is filtered through a nylon mesh (mesh size 30 μm).

The dispersion obtained has a solids content (90 min 180 ° C) of 60.3%. The polyepoxide obtained has a number average molecular weight of 10,305, a weight average molecular weight of 43 609 and an inconsistency of 4.2 on (each gelper determined by meation chromatography against polystyrene default). The dispersion thus obtained has a Storage stability at 23 ° C for more than 30 days.

Claims (12)

1. A process for the preparation of a sterically stabilized, non-aqueous dispersion of a polyepoxide, in which, in an organic solvent in the presence of a dispersion stabilizer, at least one epoxy resin (A) with on average at least 2 epoxy groups per molecule with at least one diol (B) of the formula ( I) HOROH (I) in which R is a group of the formula (II) is in which D is a methylene or a propylene group, and optionally with a further component (C) which has groups reactive towards epoxy or hydroxyl groups, is characterized in that

• 1) in a first stage at least part of the epoxy resin component (A) with an excess of the diol (B) of the formula (I) and, if appropriate, the component (C), based on the amount of epoxy resin used in this stage (1) ( A), is implemented and
• 2) then the reaction product obtained in stage (1) is reacted with the remaining epoxy resin component (A) and / or component (C) to give the desired end product.

2. The method according to claim 1, characterized in that that at least in stage (1) of the process as a compo nente (A) at least one liquid at room temperature epoxy resin is used. 3. The method according to claim 1 or 2, characterized records that as component (A) at least one Epoxy resin with an epoxy equivalent weight of 150 to 450 and preferably at least one epoxy resin Bisphenol A based. 4. The method according to any one of claims 1 to 3, characterized characterized in that small amounts of the diol (B) and / or the epoxy resin component (A) by others, difunctional compounds (C) are replaced. 5. The method according to any one of claims 1 to 4, characterized characterized in that in stage (1) of the process reaction product obtained a phenoxy equivalent weight of at least 256, preferably at least 682 and particularly preferably of a maximum of 20,000 and / or the poly obtained in step (2) of the process epoxy resin an equivalent weight of functional Has groups from 678 to infinity. 6. The method according to any one of claims 1 to 5, characterized characterized in that the reactions in stage (1) of Process with a dispersion solids content of 20 to 80% by weight, preferably from 50 to 70% by weight, and in step (2) for a dispersion solid body holds from 25 to 85% by weight, preferably from 55 to 75 % By weight. 7. The method according to any one of claims 1 to 6, characterized characterized in that in stage (1) of method 1  mol of the epoxy resin component with 3 to 1.001 mol, preferably with 1.5 to 1.02 mol, of the diol component be implemented. 8. The method according to any one of claims 1 to 7, characterized characterized in that a stabilizer that a sol dated component derived from polybutadiene comprises, and preferably a stabilizer, the one with the anchor component associated with the epoxy resin, in particular special an anchor component that is a homopolymer from methyl methacrylate or a copolymer from methyl methacrylate and acrylic acid and / or methacrylic acid, is used. 9. The method according to any one of claims 1 to 8, characterized characterized in that high-boiling ali phatic hydrocarbons, preferably aliphatic Hydrocarbons with a boiling point between 120 and 280 ° C can be used. 10. Sterically stabilized, non-aqueous dispersion one according to a method according to one of the claims 1 to 9 produced polyepoxide. 11. Coating agent based on a steric stabilized, non-aqueous dispersion of a Polyepoxide, characterized in that it is the Dispersion according to claim 10 contains. 12. Use of the coating compositions according to claim 11 for coating packaging, in particular for Coating of food packaging containers.