DE102005029792B4 - Curing agent for aqueous epoxy resin dispersions - Google Patents

Abstract

hardener for watery or solventless Epoxy resin dispersions obtained by reacting a polyepoxide compound with an amine compound at temperatures from room temperature to 200 ° C and followed by Isolation of the curing agent by separation of the excess amine compound, characterized in that the amine compound is an amine having two active, for the crosslinking is suitable hydrogen atoms.

Description

The Invention relates to curing agent for aqueous epoxy resin dispersions, wherein the curing agent is a having a linear structure. The curing agent is by reaction of an addition compound, which consists of a Polyepoxide compound and a Polyalkylenpolyetherpolyol obtained was obtained with an amine compound. The amine compound used has a functionality on, the formation of linear structures of the curing agent allowed.

Aqueous curing agents for epoxy resins are known in the art. In most cases, these aqueous epoxy systems are applied in thin layers as a lacquer. In the EP 0 637 324 B1 an aqueous hardener is described, which allows curing in thick layers, eg 5 mm. After curing, however, these layers show a behavior which is typically hard and brittle for epoxy binders. This property is not always desirable, since in many applications, for example in the floor area, an impact-resistant or slightly elastic behavior is desired, as is the case, for example the polyurethanes is known. This elastic behavior of the epoxy binders is advantageous not only in aqueous but also in solvent-containing and solvent-free systems.

To The prior art is commonly used as a curing agent for epoxy resins highly functional amines used, i. Amines that a variety having active hydrogen atoms. Examples of common amines are isophoronediamine (IPD) with 4 active hydrogens, triethylenetetramine (TETA) with 6 active Hydrogens, m-xylylenediamine (MXDA) with 4 active hydrogens, Trimethylhexamethylenediamine (TMD) with 4 active hydrogens and Pentaethylenehexamine (PEHA) with 8 active hydrogens. by virtue of high reactivity, i. the variety of active hydrogens, occurs in these compounds a strong crosslinking of the binder matrix, which then becomes a correspondingly strong brittleness leads.

task The present invention was therefore to provide curing agents, the provision of coatings with high elasticity and on the other side low brittleness allows.

These Task is performed by the curing agent with the features of claim 1 and by the coating with the features of claim 16 solved. In claim 18 is a use according to the invention the curing agent described. The other dependent claims show advantageous developments.

According to the invention is a hardener for watery or solventless Epoxy resin dispersions provided by reacting a Polyepoxide compound is obtained with an amine compound. The Reaction is at temperatures in the range of room temperature up to 200 ° C carried out. The curing agent is isolated after the reaction by removal of the excess amine compound.

special A feature of the present invention is that as the amine compound an amine with two active, for the crosslinking of suitable hydrogen atoms is used.

Preferably For example, the amine compound has a molecular weight in the range of 30 up to 430 g / mol. The amine compound may be an aliphatic, cycloaliphatic, araliphatic, heterocyclic amine or a Be a mixture of these. Particularly preferred as amine compound B Amines are selected from the group consisting of dialkylaminopropylamine, Monoalkylamine, hydroxyalkylamine, alkoxyalkylamine and polyethermonoamine used. In particular, cyclohexanamine, octylamine and diethylaminopropylamine prefers.

Under Polyepoxide are basically to understand all compounds with epoxy functionality. A preferred Variant provides that the polyepoxide compounds adducts a polyalkylene polyether polyol and a polyepoxide.

Examples of suitable polyepoxides are oligomers of epichlorohydrin and the like, epoxy ethers of polyhydric alcohols (ethylene, propylene and butylene glycols, polyglycols, thiodiglycols, glycerol, pentaerythritol, sorbitol, polyvinyl alcohol, polyallylalcohol and the like), epoxy ethers of polyhydric phenols (resorcinol, hydroquinone , Bis (4-hydroxy-phenyl) -methane, bis (4-hydroxy-3-methylphenyl) -methane, bis (4-hydroxy-3,5-dibromophenyl) -methane, bis (4-hydroxybenzoyl) 3,5-difluorophenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl ) -propane, 2,2-bis (4-hydroxy-3-chlorophenyl) -propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) -propane, 2,2-bis (4 -hydroxy-3,5-dichlorophenyl) -propane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) phenylmethane, bis (4-hydroxyphenyl) diphenylmethane, bis (4-hydroxyphenyl) -4'-methylphenylmethane, 1,1-bis (4-hydroxyphenyl) -2,2,2-trichloroethane, bis (4-hydroxyphenyl) - (4-chlorophenyl) -methane, 1,1 Bis (4-hydroxyphenyl) cyclohexane, bis (4-hydroxyphenyl) cyclohexylmethane, 4,4'-dihydroxydiphenyl, 2,2'-dihydroxydiphenyl, 4,4'-dihydroxydiphenylsulfone and their hydroxyethyl ether, phenol-formaldehyde condensation products , such as phenol alcohols, phenol-aldehyde resins and similar, S- and N-containing epoxides, (N, N-diglycidylanillin, N, N'-dimethyldiglycidyl-4,4-diaminodiphenylmethane) and epoxides, which by conventional methods of polyunsaturated carboxylic acids or monounsaturated Carboxylic acid residues of unsaturated alcohols have been prepared, glycidyl esters, polyglycidyl esters, which can be obtained by polymerization or copolymerization of glycidyl esters of unsaturated acids or from other acidic compounds (cyanuric acid, diglycidyl sulfide, cyclic trimethylene trisulfone or their derivatives and others) available are.

The above polyepoxides, this term also includes the term epoxy resin one, can individually or in a mixture, if appropriate in the presence of solvents or plasticizers, implemented according to the present process or be used for the preparation of dispersions. You can also used in mixtures with monoepoxides. For example, find the following monoepoxides in admixture with the aforementioned epoxy compounds Use: epoxidized, halogenated epoxides, e.g. epichlorohydrin, Epoxy ethers of monohydric alcohols (methyl, ethyl, butyl, 2-ethylhexyl, Dodecyl alcohol and others), epoxy resins of monohydric phenols (phenol Cresol and other ortho or para substituted phenols), Glycidyl ester of unsaturated Carboxylic acids, epoxidized esters of unsaturated Alcohols or unsaturated carboxylic acids and the acetals of glycidaldehyde.

When Preferred mer phenols are resorcinol and various Bisphenols obtained by condensation of phenol with aldehydes and ketones, e.g. Formaldehyde, acetaldehyde, acetone, methyl ketone ketone et al., receives, used. Resins of this type are disclosed in US-A-2,855,159 and 2,589,245 described.

Especially preferred epoxy resins are polyphenol glycidyl ethers, e.g. the reaction product from epichlorohydrin and 2,2-bis (4-hydroxyphenol) propane (= bisphenol A).

suitable Polyalkylene polyether polyols for the preparation of the adducts are e.g. the addition products of alkylene oxides to polyhydric alcohols or other H-acidic compounds, e.g. Amines with one or more primary or secondary Amino groups. Suitable alkylene oxides are e.g. Ethylene oxide, propylene oxide, Butylene oxide and amylene oxide. As polyhydric alcohols are aliphatic Alcohols individually or in admixture, e.g. Ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentanediol, 1,4-pentanediol, 1,3-pentanediol, 1,6-hexanediol, 1,7-heptanediol, Glycerine, 1,1,1-trimethylolpropane, 1,1,1-trimethylolethane, hexane-1,2,6-triol, α-methylclycoside, Pentaerythritol and sorbitol.

The Polyalkylenpolyetherpolyole can also be prepared from other starting materials, e.g. from tetrahydrofuran and alkylene oxide-tetrahydrofuran copolymers; epihalohydrins, e.g. Epichlorohydrin.

The alcohols or other proton-containing compounds useful as starting molecules can be reacted with one or more alkylene oxide (s) individually or in admixture, such that statistical or co-polymer block copolymers can result when using multiple alkylene oxides. The polyalkylene polyether polyols have primary and / or secondary hydroxyl groups, preferably primary hydroxyl groups, and are preferably polyethers prepared from alkylene oxides having 2 to 6 carbon atoms, eg, polyethylene ether glycols, polypropylene ether glycols, and polybutylene ether glycols. The polyalkylene polyether polyols can be prepared by any known method. The average molecular weight of the component (A ₂ ) is preferably 200 to 1000, in particular 600 to 4000.

The addition compound is preferably formed from a polyepoxide compound selected from the group consisting of bisphenol A diglycidyl ethers and bisphenol F diglycidyl ethers. But there are also more poly compounds used, with respect to these compounds expressly to the EP 0 000 605 B1 and their related disclosure is referenced.

in the Trap solvent-free hardener As polyepoxide compound, it is preferable to use a bifunctional polyepoxide used. Particularly preferred are the polyepoxide compounds selected here from the group consisting of butanediol diglycidyl ether, hexanediol diglycidyl ether, Neopentyl glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, Polypropylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether.

Solvent-free systems according to the concept of the invention show macroscopic properties as the aqueous systems, ie in terms of impact resistance and in particular elasticity. The choice of amines and Epoxidverbinungen here is not so much dependent on the water solubility and the emulsifying capacity. Decisive in the preparation of a solvent-free system is the viscosity of the adduct to enable a practical hardener formulation.

The for the Production of solvent-free Systems used amine compounds should as in the aqueous hardener not too high molecular weight, as this increases the reactivity, i. the hardening, negatively affected becomes.

Also Inventive solvent-free hardener enable the application in thin layers. The processing viscosity can, if necessary, with organic solvents be set.

According to the invention preferably as Polyalkylenetherpolyole, Polyethylenetherglycole and Polypropylenetherglycole used.

For the preparation of the addition compounds A, a catalyst is preferably used. For this purpose, a BF ₃ diethyl ether or a BF ₃ -amine complex is particularly preferably used. With respect to the other possible catalysts is on the relevant disclosure of the EP 0 000 605 directed.

According to the invention as well an epoxy resin-based coating provided with a curing agent, cured as described above has been. Such a coating has a particularly high elasticity, the Expressed in the tensile strain in the range of 10 to 400%.

Based The following examples are intended to illustrate the subject matter of the invention be explained in more detail, without restrict this to the embodiments shown here want.

example 1

300 g of polyethylene glycol, average molecular weight 1000, 428 g of bisphenol F diglycidyl ether having an epoxide equivalent weight (EEW) of 167 and 1.3 g of BF3 benzylamine complex (eg Heyl, Berlin) are dissolved in a 1 l three-necked flask equipped with a thermometer and stirrer, weighed. It is heated to 170 ° C and held this temperature until the theoretical EEW value of 372 g / eq is reached.
Found EEW value: 374 g / eq
Viscosity (25 ° C): 2.1 Pas

Example 1B

204 g (2 mol) of dimethylaminopropylamine (DMRPA) are placed in a 1 l flask with thermometer and stirrer and heated to 100.degree. With good stirring, 374 g (1 eq) of the epoxide compound of Example 1A are added slowly. After complete addition is stirred at 130 ° C for 30 minutes. Subsequently, the temperature is increased and distilled off only at atmospheric pressure and later in vacuo, the excess amine completely. There were obtained 97.2 g of distillate. After cooling to 80 ° C, 206 g of water are added, homogenized to obtain a 70% aqueous solution.
Viscosity (25 ° C): 1.87 Pas
Amine number: 162 mg KOH / g
H equivalent weight: 690 g / eq

Example 2

As described in Example 1B, 612 g (6 mol) of DMAPA are reacted with 324 g (3 eq) of butanediol diglycidyl ether and the excess amine is distilled off. There were obtained 293.8 g of distillate. After cooling to 80 ° C, 282.9 g of water are added, homogenized to obtain a 70% aqueous solution.
Viscosity (25 ° C): 305 m Pas
Amine number: 364 mg KOH / g
H equivalent weight: 300 g / eq

Example 3A

As described in Example 1A, 360 g of polypropylene glycol, average molecular weight 1200, 401 g of bisphenol F diglycidyl ether having an EEW of 167 and 1.25 g of BF3 benzylamine complex are reacted to the theoretical EEW of 422 g / eq.
Found EEW value: 432 g / eq
Viscosity (25 ° C): 7.8 Pas

Example 3B

As described in Example 1B, 144 g (2.4 mol) of ethylenediamine are reacted with 518.4 g (1.2 eq) of epoxide adduct from Example 3A and the excess amine distilled off. The amount of distillate was 72 g. Subsequently, 253 g of water were added to obtain a 70% solution.
Viscosity (25 ° C): 4.12 Pas
Amine number: 171 mg KOH / g
H equivalent weight: 234 g / eq

Example 4

As described in Example 1B, 585 g (4.5 mol) of diethylaminopropylamine (DEAPA) are reacted with 322.8 g (2.25 eq) of hexanediol diglycidyl ether and the excess amine is distilled off. There were obtained 279.9 g of distillate.
Viscosity (25 ° C): 10.1 Pas
Amine number: 381 mg KOH / g
H equivalent weight: 268 g / eq

Example 5

As described in Example 1B, 306 g (3 mol) of DMAPA are reacted with 469.5 g (1.5 eq) of polypropylene glycol diglycidyl ether (POLYPOX R 19) and the excess amine is distilled off. There were obtained 145.52 g of distillate.
Viscosity (25 ° C): 2.64 Pas
Amine number: 252 mg KOH / g
H equivalent weight: 400 g / eq

Example 6

Aqueous systems

For the performance testing of the aqueous curing agents according to the invention, a dispersion is prepared with epoxy resin and fillers as follows:
0.1 g / eq of the corresponding hardener are intensively intensified with 4.5 g of water and the equimolar amount (0.1 g / eq) of a bisphenol A / F resin which has been reactively diluted with C12-14-glycidyl ether (eg POLYPOX E 403) stirred, so that a dispersion is formed. Subsequently, 66 g of finely divided quartz flour and 100 mg Byk 021 are added as a defoamer and homogenized.

Table 1

example 1B is the curing agent of the invention. Examples 2 and 3B are negative examples.

Testing as a pure binder

Table 2

The Tensile strain was on a testing machine of the company UTS test system. The test specimens were according to DIN-ISO 527-2 (Specimen A) produced.

Example 7

Solvent-free systems

0.1 g / eq of the hardener be with the equimolar Amount of bisphenol A / F resin reactively diluted with C 12-14 glycidyl ether (e.g., POLYPOX E 403) stirred vigorously. There are test specimens with made of a layer thickness of 2 mm.

Table 3

Table 4

Claims (18)

Curing agents for aqueous or solvent-free epoxy resin dispersions obtained by reacting a polyepoxide compound with an amine compound at temperatures from room temperature to 200 ° C and then isolating the curing agent by removal of the excess amine compound, characterized in that the amine compound is an amine having two active, for crosslinking suitable hydrogen atoms. hardener according to claim 1, characterized in that the amine compound has a molecular weight in the range of 30 to 430 g / mol. hardener according to one of the preceding claims, characterized the amine compound is an aliphatic, cycloaliphatic, araliphatic, heterocyclic amine or a mixture thereof. hardener according to one of the preceding claims, characterized that the amine compound is selected is selected from the group consisting of dialkylaminopropylamine, monoalkylamine, Hydroxyalkylamine, alkoxyalkylamine and polyethermonoamine. hardener according to the preceding claim, characterized in that the Amine compound selected is selected from the group consisting of cyclohexanamine, octylamine and dimethylaminopropylamine. hardener according to one of the preceding claims, characterized the polyepoxide compound is an adduct of a polyalkylene polyether polyol and a polyepoxide. hardener according to one of the preceding claims, characterized the polyepoxide compound is an adduct of a polyalkylene polyether polyol and epihalohydrin. hardener according to one of the preceding claims, characterized the polyepoxide compound is an adduct of an alkoxylated one Bisphenol and epihalohydrin. hardener according to one of the preceding claims, characterized the polyepoxide compound is an adduct of an alcohol and epichlorohydrin is. hardener according to one of the preceding claims, characterized that the polyepoxide compound is selected from the group of Bisphenol A diglycidyl ether and bisphenol F diglycidyl ether. hardener according to one of the preceding claims, characterized the polyepoxide compound is a bifunctional polyepoxide. hardener according to the preceding claim, characterized in that the Polyepoxide compound selected is selected from the group consisting of butanediol diglycidyl ether, hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, Cyclohexanedimethanol diglycidyl ether, polypropylene glycol diglycidyl ether and polyethylene glycol diglycidyl ether. hardener according to one of the preceding claims, characterized the polyalkylene ether polyol is selected from the group of Polyethylenetherglycole and Polypropylenetherglycole. hardener according to one of the preceding claims, characterized that the addition compound A is prepared in the presence of a catalyst has been. Curing agent according to the preceding claim, characterized in that the catalyst is a BF ₃ diethyl ether or a BF ₃ -amine complex. Epoxy-based coating, which with a hardener cured according to one of the preceding claims. Coating according to claim 16, characterized in that the coating has a tensile elongation of 10 to 400%. Use of the curing agent according to one of the claims 1 to 15 for the production of epoxy resin systems, in particular adhesives, Paints, coatings, mold making, tooling resin, by hot or work hardening to be obtained.