JPH0441695B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a cationic epoxy resin modified by using a substituted urea having an aminoalkylated phenol for chain extension of a diepoxy resin. chains of cationic resins, especially epoxy resins for the production of binders for cationic electrocoating (CED), in order to influence the adhesion and flexibility of crosslinked films without adversely affecting the corrosion resistance. Many attempts have been made to extend it. Attempts to increase the molecular size of low-molecular-weight epoxy resins by chain extension with diphenyl have been described, inter alia, in US Pat. Other than increasing molecular size, such methods do not achieve substantial improvements in adhesion or film forming temperatures. According to DE 1930949, adhesion and flexibility can be achieved by using long-chain monocarboxylic and/or di- or polycarboxylic acids, such as maleated oils or maleated polybutadiene, acidic alkyd resins or copolymers. It is said that this can be improved by partial esterification. According to U.S. Pat. No. 4,104,147 or 4,148,772, chain extension is carried out by reacting a cationically modified epoxy resin with a polyol having at least two primary hydroxyl groups, which improves the breakdown voltage, film forming temperature and It states that both flexibility can be improved. However, these improvements are no longer able to satisfy recent high requirements, particularly those of the automobile industry. It has recently been discovered that the use of a cationic binder having an amide structure can improve the mounting properties of cationic electrodeposited films. However, for example, US Pat.
As described in No. 4036795, in aminoamide compounds of maleated fatty acids and polyamines,
In order not to improve these properties, the method of introducing the amide structure is fundamentally important. European Patent (EP) A2-0137459 describes the possibility of introducing amide and/or urea groups, in which diamines bearing the groups described in this patent are used for chain extension of epoxy resins. It is said to be effective. A basic group that imparts cationic properties to the binder is introduced by addition of an amine. This patent application does not belong to the state of the art patent application [A713/84=Austrian patent specification (AT-PS) No. 379406/2450; JP-A-60-221467
No.], a carboxylic acid amide structure is introduced using a special secondary amine that simultaneously introduces cationic properties necessary for water dilutability into either part or all of the molecule. For example, Austrian patent (AT
-PS) No. 378537 (2390) JP-A-60-260664,
Aminoalkylated phenols are optionally used in the production of self-crosslinking electrodeposition paints. A further improvement of this principle is the Austrian patent application A3608/84 (2397) or A2331/
85 (2730). Diepoxy resins for paint binders can be advantageously improved by using molecular structural segments appropriately formed by etherification of phenols bonded to modified urea groups as chain extension structural molecules of diepoxy resins. I found out that it works. If the reaction product has a basic group due to chain extension and/or further modification, the product becomes water-dilutable due to protonation and is used as a paint binder for cathodic electrodeposition paints. It can be used as That is, the present invention relates to a method for producing a cationic epoxy resin modified by chain extension, which is obtained by the reaction of a phenol having at least one reactive site with formaldehyde, a primary amine, and formaldehyde. reaction product (A) of 2 moles of an aminoalkylation product having one NH group with 1 mole of diisocyanate, or 1 mole of substituted urea obtained from 1 mole of diisocyanate compound and 2 moles of primary amine;
A reaction product (A1) of 2 moles of formaldehyde or a formaldehyde-generating substance and 2 moles of phenol having at least one reaction site with formaldehyde, and 1 mole of a diepoxy compound per phenolic hydroxyl group to form a phenolic hydroxyl group. Etherification reaction (B), then the final product has an amine value of 35 mg or more.
This production method (C) is characterized in that the remaining epoxy groups are reacted with an amine compound and/or a carboxy compound by a known method under conditions to contain a basic nitrogen group in an amount of 150 mgKOH/g. The process according to the invention results in products which do not contain saponifiable groups in the chain-extending components, but which contain the substituted urea groups necessary to improve the adhesion of paint films. Phenols suitable for the production of chain-extending molecular segments include compounds having at least one formaldehyde-reactive site.
When phenols with a large number of functional groups are used, the product further has crosslinking properties and can be used for the preparation of self-crosslinking binders. Besides phenols, alkylphenols such as butylphenol and its congeners, diphenols and bis-(4-hydroxyphenyl)-methane or 2,
Diphenyloalkanes such as 2-bis-(4-hydroxyphenyl-)-propane may be used. Suitable primary amines include alkylamines, preferably higher homologs having 4 or more carbon atoms, and monoethanolamine and its homologues, alkanolamines. Those containing tertiary amines as primary amines can also be used. And in order to simultaneously introduce a basic group in the form of a tertiary amino group into the chain extension group, primary-tertiary diamines, such as dimethyl- or dialkylaminoalkylamines such as diethylaminopropylamine, etc. are advantageous. . Commercially available liquid formaldehyde can be used. Preferably, paraformaldehyde with a CH ₂ O content of 90% or more is used. Suitable diisocyanates include commercially available products such as toluylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, etc., or reaction products in which the molar ratio of diol to diisocyanate is 1:2. To produce intermediate (A), phenol, amine and formaldehyde are reacted in one step at 80°C to 130°C. The water of reaction is removed azeotropically by the azeotrope generator. The reaction with the isocyanate is carried out at 30°C to 50°C, preferably in the presence of an aprotic solvent, and the isocyanate compound is
It is added little by little under cooling until the NCO value reaches zero. During the preparation of intermediate (A1), the amine is dissolved in an aprotic solvent and the diisocyanate is added with cooling at 30°C to 60°C. The reaction usually ends upon completion of the addition. After adding formaldehyde and phenol, the reaction is carried out at 80°C to 103°C, and the reaction water is removed by azeotropic distillation. The reaction between the chain extender and the epoxy resin is carried out in a conventional manner to produce a phenol ether. The reaction is
0.05 to 0.2 of triethylamine as a basic catalyst at 90 to 120 °C in the presence of a solvent.
This can be done advantageously using weight percentages. Epoxy resins suitable for the production process according to the invention are commercially available di- or polyepoxy compounds obtained by the reaction of polynuclear phenols, in particular bisphenol A or phenol novolacs, with epichlorohydrin. Other epoxy resins, such as polyol-based epoxy resins, can also be used if desired. Products of this type are well known to those skilled in the art and are described in detail in the literature. Preferred epoxy resins for this production method are those based on bisphenol A or phenol novolak, and have an epoxy equivalent of 180 to 1,000. The diepoxy resin is modified by introducing a basic group simultaneously with the reaction with the chain-extending constituent molecules or after the reaction, such as by an epoxy amine production reaction or an esterification reaction with carboxy compounds of various structures. Unsaturated groups can also be introduced, for example by reaction of hydroxyacrylates with half esters of dicarboxylic acids. Further, a basic group can be introduced by reacting a free hydroxy group with a basic monoisocyanate. If necessary, modification can be performed before the chain extension reaction. It is important that substantially all epoxy groups react;
The final product must be free of epoxy groups. In order to impart water dilutability, the basic groups of the reaction product are partially or completely neutralized with an acid, preferably formic acid, acetic acid or lactic acid. To obtain the dilutability required for practical use, 10% to 40% of the basic groups must be neutralized, or approximately 20% of the acid should be added to 100 g of resin solids.
It is sufficient to use amounts of from 60 mmol to 60 mmol. The binder is diluted with deionized water to the required concentration. If necessary, pigments, extenders, and other paint additives can be mixed with the binder before neutralization or dilution, or in a partially diluted state, to obtain a pigmented paint. The formulation of such coatings and their use in electrodeposition coatings are known to those skilled in the art and are described in the literature. When used as a primer, the electrodeposited film is cured at 150°C to 170°C for 10 to 30 minutes. If the binder is not sufficiently self-crosslinked, addition crosslinking agents such as blocked isocyanates, transesterification curing agents, amino resins or phenolic resins may be used in combination. Depending on the appropriate formulation, it is also possible to apply by other methods, for example by dipping, rolling or spraying. If desired, the binder according to the method of the invention can be used in an organic solvent. The following examples are illustrative of the invention but are not intended to limit the scope of the invention in any way. Parts and percentages represent weight unless otherwise specified. The following abbreviations are used in the examples: DEA Diethylamine DEAPA Diethylaminopropylamine DMAPA Dimethylaminopropylamine DOLA Diethanolamine EHA 2-ethylhexylamine HA n-hexylamine IBA Isobutylamine MEOLA N-methylethanolamine MIPA Monoisopropanolamine BPA Bisphenol A BPF Bisphenol F DMP 2,6-dimethyl Phenol NPH Nonylphenol NPB n-Butylphenol PH Phenol PF91 91% paraformaldehyde IPDI Isophorone diisocyanate ODI 1 mole of 1,8-octanediol and IPDI2
Mol of reaction product TDI Toluylene diisocyanate (commercially available monomer mixture) TMDI Trimethylhexamethylene diisocyanate EHX/TDI 2 of toluylene diisocyanate
- Ethylhexanol semi-block product EPH Bisphenol A-based diepoxy resin (epoxy equivalent: approx. 475) EPH Bisphenol A-based diepoxy resin (epoxy equivalent: approx. 190) CE 1,1-dimethyl-(C ₇ -C ₉ )-alkane Technical mixture of glycidyl esters of carboxylic acids DMPS dimethylolpropionic acid HE 1 Half ester of phthalic anhydride and hydroxyethyl oxazolidine, DGDE 70% solution (molecular weight 265) HE 2 Half ester of tetrahydrophthalic anhydride and hydroxyethyl methacrylate ( (molecular weight approx. 282) BM Basic monoisocyanate, MIBK 60% solution (molecular weight
239) DGDE Diethylene glycol Dimethyl ether MIBK Methyl isobutyl ketone PGME Propylene glycol monomethyl ether The phenol component and the amine, as well as an azeotrope, such as toluene, to remove the water of reaction are placed in a reactor and heated to about
Heat to 75°C. After adding formaldehyde, preferably in the form of paraformaldehyde, the temperature is slowly increased until continuous azeotropic distillation occurs. Once the calculated amount of water of reaction has been removed, the azeotrope is removed in vacuo and the reactants are dissolved in a previously prepared aprotic solvent. The isocyanate is added in portions at 30°C to 50°C while cooling the above solution until the NCO number is essentially zero. The intermediate is diluted with the solvent listed in Table 1 to give the solids content in Table 1. Reaction products of type (A1): Amines (mixtures) according to the amounts listed in Table 1a.
and a solvent are charged into a reactor. The diisocyanate is added continuously with cooling at 30°C to 50°C over 30 to 60 minutes. Once the addition is complete, heat the mixture to 70°C and add paraformaldehyde. Phenol is added while maintaining this at 70°C to 80°C, and a suitable azeotrope, such as toluene, is added to remove the reaction water azeotropically at this temperature. After removing the azeotrope in vacuo, the reaction product is diluted to the solids listed in the table.

【table】

[Table] Example 1 475 parts (1 Val) of EPH was added in a suitable reactor.
Dissolve in 204 parts of PGME, add 181 parts of intermediate Zp1 (resin solid content: 136 parts = 0.2 mol) and 0.5 part of triethylamine as a catalyst, and continue the reaction at 110°C until the free epoxy group becomes 0.6 mol. reactant
Cool to 75°C and add 26 parts (0.2 mol) of DEAPA.
and 21 parts (0.2 mol) of DOLA are added and reacted at 80°C to reduce the epoxy value to zero. The reaction product is
Dilute with 105 parts of PGME to 65% solids.
The amine value has 51 mgKOH/g. Example 2 Same as Example 1, 190 parts of EPH (1Val)
and a mixture of 475 parts (1Val) of EPH
It was dissolved in 222 parts of PGME and reacted with 461 parts of Zp2 (corresponding to 346 parts of resin solid content = 0.5 mole, equivalent to 1 mole of phenolic hydroxyl group) in the presence of 1.0 part of triethylamine at 115°C, so that 1 epoxy group was dissolved. Continue the reaction until the amount corresponds to mol. The reaction mixture was cooled to 60°C, and 15 parts (0.2 mol) of MEOLA was added to it.
Add 41 parts (0.4 mol) of DMAPA and react until the epoxy value becomes zero. The reactant was diluted with DGDE to give a solids content of 70% and an amine value of 52 mgKOH/g. Example 3 380 parts (2 Val) of EPH, 189 parts of HE1 (133 parts of resin solid content = 0.5 mol) and 243 parts of ZP4 (170 parts of resin solid content = 0.2 mol, equivalent to 0.8 mol of phenolic hydroxyl group) were added to 90 parts of EPH. Stir for 1 hour at °C. 22 parts (0.3 mol) of DEA, 26 parts (0.2 mol) of DEAPA, and 184 parts of BGME are added to the reaction mixture at 65°C, and these are reacted at 75°C until the epoxy value becomes zero. The solid content of the reaction product is 70%, and the amine value is
It is 100mgKOH/g. Example 4 950 parts of EPH (2Val) and 152 parts of EPH (0.8Val) were dissolved in 698 parts of MIBK and added to this solution.
Add 508 parts of HE2 (1.8 moles) and 560 parts of ZP3 (392 parts of resin solids = 0.5 moles). This mixture was reacted at 110°C in the presence of 1.5 parts of triethylamine,
Set the epoxy value to zero. The reactant was cooled to 60°C, and the BMI was 1194 parts (resin solid content 836 parts = 3.5 moles).
at 60℃ until all isocyanate groups have reacted.
Keep it. The obtained binder is cured by thermal polymerization, and has a solid content of approximately 70% and an amine value of 69mgKOH/
It is g. Example 5 285 parts of EPH (1.5 Val) were mixed with 384 parts of ZP5 (resin solids 268 parts) in the presence of 0.2 part of triethylamine.
part = 0.25 mole) at 110°C until the free epoxy group becomes 1 mole. Bring the reaction to 65°C,
59 parts (0.45 moles) of DEAPA and 58 parts (0.45 moles) of EHA are added to the reactants and reacted at 70°C until the epoxy value becomes zero. Furthermore, this reaction product was added to 300 parts of PGME and 30 parts of NBP.
part (0.2 mole), BPA160 part (0.7 part) and PF91
React with 66 parts (2 mol) at 70°C until the free formaldehyde content is below 0.3%. This resin is diluted with PGME to a solids content of 65%.
The amine value of this resol curing binder is 86mg
KOH/g. Example 6 304 parts of EPH (1.6 Val) in the presence of 76 parts of PGME and 0.2 parts of triethylamine, 336 parts of ZP3 (235 parts of resin solids = 0.3 mole) and 0.6 mole of epoxy group consumed at 110°C React until. (Reaction component A) In another reactor, 228 parts (1 mol) of bisphenol A, 260 parts (2 mol) of DEAPA, and 66 parts of PF91 were added.
(2 mol) are reacted in the presence of 131 parts of the azeotrope toluene until 42 parts of the water of reaction have been separated.
The reaction was cooled to 30°C and 608 parts of EHX/TDI (2.0
mol) within 45 minutes. Once the epoxy value becomes practically zero, the reaction product can be immediately removed.
Dissolve in 152 parts of DGDE (reaction component B). 716 parts of reaction component A and 1403 parts of reaction component B,
Mixed with 361 parts of PGME and 250 parts of CE (1 mole),
React at 95℃ to 100℃ until the epoxy value becomes zero. The solids content of the reaction product is 70% and the amine value is 59 mgKOH/g. For the subsequent steps, 0.6 parts of a tin catalyst such as dibutyltin dilaurate (calculated as metal) is added per 100 parts of resin solid content. Example 7 Example 4 except that 586 parts of ZP6 (resin solid content 410 parts = 0.5 mol) was used instead of ZP3 as the resin solution.
Operate in the same way. Example 8 760 parts of EPH (4.0 Val) was dissolved in 326 parts of PGME and dissolved in the presence of 1 part of triethylamine.
DMPS 268 parts (2 mol) and acid value 2 mg at 100℃
React until the amount is below KOH/g. Next, ZP7
1677 parts (1174 parts resin solids = 1.0 mole) are added to the reactants and the reaction is carried out at 95°C to 100°C until all the epoxy groups have reacted. This is diluted with PGME to give a solid content of 65%. The amine value of the product is 51mg
KOH/g. Example 9 A resin solution is prepared in the same manner as in Example 2, except that 494 parts of ZP8 (346 parts of resin solids = 0.5 mole) is used instead of ZP2. Testing of binders according to the method of the present invention The binders obtained in Examples 1 to 9 were uniformly mixed with a curing agent at 60°C according to the resin solid amounts listed in Table 2, and pigmented paints were prepared from this mixture. . In preparing a pigmented paint, the following formulation was made into a pigment paste using a suitable mixing device, and this was uniformly mixed with 75 parts (solid content) of a binder mixture to prepare a pigmented paint. Binder hardener mixture (100%) 25 parts Carbon black 0.25 parts Basic lead silicate pigment 3 parts Titanium dioxide 36.75 parts The following components were used as the hardener. Curing agent component X: transesterification curing agent based on malonic acid ester of AT-PS 372099, for example according to "component B2". Curing agent component Y: AT-PS 379602 (A 2532/83)
For example, a transesterification curing agent based on a modified malonic ester according to Example 1 (U.S. Pat. No. 4,523,007). Hardener component Z: Example of EP-B1-00 12463
Transesterification curing agent based on oligomeric beta hydroxy ester according to 6b. The pigmented paint was neutralized and diluted as listed in Table 2, and then cationically electrodeposited onto a zinc phosphate steel plate to a dry film thickness of 20 ± 2 μm, and then heated at the temperature shown in Table 2. Cured for 30 minutes. ASTM B-
117-64, the degree of corrosion of the cross-cut specimen after 700 hours was 2 mm in all cases.
It was below. The coating film was in good condition after being left in a high temperature chamber (50°C, relative humidity 100%) for 500 hours. To test the adhesion of PVC materials to cationically electrodeposited paint, 30 pieces of PVC 1 cm wide and 2 mm thick were
This was applied to a cationic electrodeposition primer and cured at 140° C. (objective temperature) for 7 minutes. Adhesion tests were conducted 1 hour after curing. The peeling state of the PVC layer was evaluated on a 5-grade scale. (5 = easily peeled off, 1 = not peeled off, test piece was destroyed) The tested PVC materials were commercially available car body underbody protection materials (Stankiewicz 2252 manufactured by Stankiewicz, West Germany) and A commercially available seam sealant used in the automobile industry (Dekelin 9003, manufactured by Krebstzukwerke, Hanau, Germany) was used.

[Table] For comparative testing, 30 parts of the binder (resin solids) of Example 29 of U.S. Pat. No. 4,174,332 and EP
-B1-00 12463 and 70 parts of the binder (resin solid content) of Example 8 were used as a binder and a paint was prepared in the same manner as a comparative paint A. Comparative paint B is one in which the ratio of the above components is changed to 50:50. Comparative paint C was prepared based on the binder composition according to Example 4 of EP-B1-0049369.
Neither binder contains substituted urea groups. The composition of each coating with a solids content of about 18% is shown in Table 2.

【table】

【table】

Claims (1)

[Scope of Claims] 1. In a method for producing a modified cationic epoxy resin by chain extension, one phenol having at least one reactive site with formaldehyde, a primary amine, and formaldehyde are reacted. reaction product (A) of 2 moles of an aminoalkylation product having NH groups with 1 mole of diisocyanate, or 1 mole of diisocyanate compound and primary amine 2
a reaction product (A1) of 1 mole of substituted urea obtained from 1 mole of substituted urea, 2 moles of formaldehyde or a formaldehyde-generating substance, and 2 moles of phenol having at least one reaction site with formaldehyde; The phenolic hydroxyl group is etherified with mol (B), and then the amine value of the final product is 35 mg to 150 mg.
A production method (C) characterized in that the remaining epoxy groups are reacted with an amine compound and/or a carboxy compound in a conventional manner under conditions to contain a basic nitrogen group in an amount such that KOH/g. 2 Reaction product (A) and (A1) of 1st-tertiary diamine
The production method according to claim 1, which is used as a primary amine in the production of. 3. The manufacturing method according to claim 1 or 2, wherein the reaction with the amine and/or carboxy compound is carried out simultaneously with or after the reaction of the chain extension constituent molecule with the epoxy compound. 4. The manufacturing method according to claim 3, wherein a half ester of dicarboxylic acid and hydroxy (meth)acrylate is used as the carboxy compound.