JPH035414B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a coating resin that provides a coating with excellent impact resistance and corrosion resistance. More specifically, the present invention relates to a method for producing a piperazine ring-containing polyhydroxypolyetheramine having excellent impact resistance, corrosion resistance, adhesion, thermal properties, and mechanical properties. Epoxy resins and epoxy-modified polyol resins have excellent adhesion to metals and corrosion resistance, and are widely used as undercoat paints. However, in recent years, due to the desire to streamline the painting process and save resources, there has been a growing trend to omit or reduce the painting process or improve workability, and there has been a growing demand for high-performance paints. Generally, epoxy resins that cure at room temperature require an amine-based curing agent and are a two-component type. Also, in the case of epoxy modified polyol resin, polyisocyanate is required as a curing agent, and it is a two-component system. Two-component systems have drawbacks such as limited pot life and the need for measuring. Polyhydroxypolyether resins called phenoxy resins with a molecular weight of 30,000 to 40,000 are available to compensate for this drawback to some extent, but these systems tend to have poor secondary adhesion because they are not crosslinked. Although phenoxy resin has superior impact resistance compared to general epoxy resins, it still does not provide satisfactory secondary adhesion after impact resistance. As mentioned above, in order to streamline the painting process, it is necessary for pre-painted metal materials to withstand strong deformation and impact during cutting and bending, and to maintain coating properties such as corrosion resistance on processed parts. It is. The present inventors have worked diligently to provide a new coating material that essentially belongs to the phenoxy type, but has extremely excellent corrosion resistance, toughness, adhesion, and impact resistance that fully compensates for the above-mentioned drawbacks. As a result of repeated research, the present invention was completed. That is, the present invention is a reaction product of N-aminoethylpiperazine and a dibasic acid or a dibasic acid lower alkyl ester, which is an organic amine containing two piperazine rings and two secondary amines in one molecule, and a diepoxy This is a method for producing a piperazine ring-containing polyhydroxypolyetheramine, which is characterized by reacting a compound with an amino group and an epoxy group in substantially equal moles or in a small excess mole of amino groups.
A piperazine ring is introduced into the molecule of the polyhydroxy polyether amine of the present invention, and the adhesion to the underlying metal is significantly improved by the action of nitrogen of this cyclic tertiary amine. Furthermore, since the molecule does not contain an ester bond, it has excellent alkali resistance and water resistance. Furthermore, it is known that cyclic compounds have better heat resistance than linear compounds, and improvement in heat resistance can be expected. It was also found that the polyhydroxypolyetheramine of the present invention has very good impact resistance. This is due to the fact that the reaction between the secondary amine, which is the organic amine of the present invention, and the epoxy group increases the molecular weight uniformly and smoothly, the molecular weight distribution is sharp, and there are few components in the low molecular weight region. Seem. As a compound similar to the polyhydroxypolyetheramine of the present invention, a method for producing polyhydroxypolyetheramine by reacting a bifunctional epoxy compound with a primary monoamine has also been proposed (Japanese Patent Publication No. 35-11796, No. 36-1993). issue,
No. 51-18973), however, polymerization by the reaction between a primary amine and an epoxy is actually a two-step reaction. That is, the primary amine and epoxy react to generate a secondary amine, and the generated secondary amine and epoxy react. However, there is a large difference in the reaction rate of primary amines and secondary amines with epoxy, with primary amines having a reaction rate 50 to 100 times faster than secondary amines. Furthermore, the secondary amine produced by addition of the primary amine is substituted with an alkyl group derived from the amine, and this acts as a steric hindrance, significantly slowing down the addition reaction of the secondary amine to the epoxy. do. As a result, the molecular weight of the polyhydroxypolyetheramine obtained by the reaction between a diepoxy compound and a primary amine is difficult to increase smoothly, the molecular weight distribution is wide, and many of the molecules are on the low molecular side, and they do not have self-forming properties on their own and do not require crosslinking agents. It is necessary to use it to form a film. Naturally, it has poor impact resistance.
The reaction between the epoxy and the secondary amine of the piperazine ring of the present invention does not substantially cause steric hindrance, and since only the secondary amine is used from the beginning, there are no adverse effects due to differences in reaction rates. It is possible to create polymers with sharp molecular weight distribution. Although it is possible to make the molecular weight distribution relatively sharp with the polyhydroxy polyether synthesized from bisphenol A and epichlorohydrin mentioned above, this polymer system takes 25 to 30 hours to polymerize with an alkaline catalyst. This is a long-lasting reaction. If you use a highly concentrated alkaline catalyst to shorten the reaction time, the
This is undesirable because it results in a branched polymer due to the reaction between the class hydroxyl group and the epoxy. In addition, this system requires a great deal of labor, time and energy to remove the alkali catalyst, which increases production costs. Mata Tokuko Showa 53-
No. 20080 lists 2,5-piperazine, 2,6-piperazine, 2,4-imidazolidione, 5,6-
A method for producing a thermoplastic resin for coating and molding by reacting a nitrogen-containing heterocyclic compound such as dihydrouracil or barbituric acid with an epoxy compound is disclosed. All of the above nitrogen-containing heterocyclic compounds have a carbonyl group in the ring, and the carbonyl is the carbon atom adjacent to nitrogen (secondary amine). In other words, as expressed by -CONH-,
This hydrogen bonded to nitrogen has properties similar to so-called amide hydrogen, and has significantly lower reactivity with epoxy groups than general secondary amine hydrogen. In fact, all of the examples described in Japanese Patent Publication No. 53-20080 use a catalyst (quaternary ammonium salt), and the reaction time is long, 35 to 60 hours at 100 to 110°C. Productivity is extremely poor. Also, since a catalyst is used, which is not removed, it may cause performance problems and is therefore unsatisfactory. In contrast, the method according to the invention uses only essentially linear polymers and a reaction time of 5 to 6 hours is sufficient;
There is no need to remove the catalyst, and it can be said to be superior to conventional polymer systems in all aspects. The organic amine used in the present invention is represented by the following formula [], However, R ^c is synthesized by an amide reaction from the dibasic acid residue N-aminoethylpiperazine and the dibasic acid or dibasic acid lower alkyl ester, and the usable dibasic acids or their esters include adipic acid, sebatin acid,
1.10 decacarboxylic acid, high purity dimer acid obtained by polymerization of tall oil fatty acids, aromatic dicarboxylic acids such as isophthalic acid and terephthalic acid, butadiene-acrylonitrile liquid rubber with terminal carboxylic acid, and low molecular weight terminal carboxylic acid. Polyester oligo etc. can be used. The diepoxy compound used in the present invention can be obtained by reacting divalent phenol and epihalohydrin in a conventional manner. As a divalent phenol, mononuclear 2 having one aromatic nucleus is used.
There are polyvalent phenols and polynuclear divalent phenols having two or more aromatic nuclei. Examples of mononuclear divalent phenols include, for example, resorcinol, 4,6-dichloro-resorcinol, hydroquinone, 2-
Bromo-hydroquinone, birocatechol, phloroglucinol, 1,5-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,6
-Dihydroxynaphthalene, etc. In addition, examples of polynuclear divalent phenols include 2,2-bis-
Various bis(hydroxyphenyl) alkanes represented by (4-hydroxyphenyl)propane (bisphenol A), various dihydroxybiphenyl represented by 4,4'-dihydroxyphenyl, or bis-( 4-hydroxyphenyl)
Examples include various di(hydroxyphenyl) sulfones represented by sulfones, and various di(hydroxyphenyl) ethers represented by bis(4-hydroxyphenyl) ether. Furthermore, 1,1-bis(4-hydroxyphenyl)-2-
Phenylethane, 1,3,3-trimethyl-1-
(4-hydroxyphenyl)-6-hydroxyindan, 2,4-bis(p-hydroxyphenyl)
-4-Methylpentane can also be used. Examples of epihalohydrin include epichlorohydrin, epibromohydrin, 1,2-epoxy-2-methyl-3-chloropropane, 1,2-epoxy-2
-Ethyl-3-chloropropane and the like. Catalysts that promote the reaction between the epihalohydrin and divalent phenol include Lewis acids such as boron trifluoride, stannic chloride, zinc chloride, and ferric chloride, and derivatives exhibiting these activities (e.g., trifluoride). Examples include acidic catalysts such as boron-ether complex compounds) or mixtures thereof, and basic catalysts such as alkali metal hydroxides, alkali metal alcoholates, tertiary amine compounds, quaternary ammonium compounds, or mixtures thereof. The epoxy compound is produced simultaneously with this reaction, or the polyhalohydrin ether produced as a result of the reaction is ring-closed by a dehydrohalogenation reaction to produce the epoxy compound. The basic compounds used in this dehydrohalogenation reaction include alkali metal oxides,
An alkali metal aluminate or the like is used. These catalysts and basic compounds can be used as they are or as a solution in an appropriate inorganic or organic solvent. The method for producing the piperazine ring-containing polyhydroxypolyetheramine of the present invention can be carried out as follows. That is, the organic amine of the present invention and the epoxy compound may be charged in substantially equal molar amounts or in slight excess, and if desired, a ketone type, ether type, ester type, phenol type, aromatic hydrocarbon/alcohol mixed type, etc. may be used as a solvent. good. The thus obtained piperazine ring-containing polyhydroxypolyetheramine can be used alone, but it can be used in combination with one selected from epoxy resins, urea melamine resins, polyurethane resins, polyurethane prepolymers, phenolic resins, alkite resins, polyester resins, etc. A species or two or more kinds of resins can be contained within a desired objective range. Further, if necessary, diluents, dyes, pigments, fillers, plasticizers, crosslinking agents, etc. can be included. The effects of the present invention are that the piperazine-containing polyhydroxypolyetheramine obtained has a high molecular weight and can be used as a warming lacquer type paint, and can also be used in combination with a crosslinking resin to create base paints for pre-coated metals, wire coating paints, magnetic paints, and cans. It is also useful for paints, etc. The present invention will be explained below with reference to Examples, but the present invention is not limited to these Examples. Example 1 130.3 parts (1.01 mol) of N-aminoethylpiperazine and 73 parts (0.5 mol) of adipic acid were charged into a separable flask, dehydrated while purging with nitrogen gas, and heated at 200°C for 4 hours. Approximately 18 ml of water was collected to synthesize a diamine (A-1) containing two piperazine rings per molecule. This substance was pale yellow and waxy. This diamine (A-1)
Synthesized from bisphenol A and epichlorohydrin in 184g (0.5 mol), epoxy equivalent 188g/
188 g (0.5 mol) of the epoxy resin of eq and 93 g of methyl ethyl ketone as a solvent were added and reacted at 60°C. After 30 minutes, 100 g of methyl ethyl ketone was added. The reaction was carried out at 60° C. for 5 hours while diluting the mixture successively in the same manner. The final solids concentration was 40%. The resulting varnish had a hue of Gardner 1, a viscosity at 25°C of Z ₆ ,
Gel permeation chromatography (hereinafter referred to as GPC)
The molecular weight distribution measured by the method was as follows: number average molecular weight (Mn) was 31,000, weight average molecular weight (Mw) was 96,000, and dispersity Mw/Mn was 3.1. Example 2 184g of diamine (A-1) synthesized in Example 1
(0.5 mol), 648.7 g (0.499 mol) of a solid epoxy resin synthesized from bisphenol A and epichlorohydrin and having an epoxy equivalent of 650 g/eq, and 555 g of methyl ethyl ketone were added, and the mixture was reacted at 50°C. The mixture was diluted successively as the viscosity increased, and after 6 hours, a varnish with a solid content of 35% was obtained. Hue Gardner 1, 25℃
The viscosity Z ₂ - Z ₃ at
It was 2.78. Example 3 130.3 parts (1.01 mol) of N-aminoethylpiperazine and 97 parts (0.5 mol) of dimethyl terephthalate were heated in the same manner as in Example 1 and amidated at 220°C for 3 hours while removing methanol to form diamine (A-
2) was synthesized. This diamine (A-2) is 38.8
g, 95 g of an epoxy resin synthesized from bisphenol A and epichlorohydrin and having an epoxy equivalent of 475 g/eq, and 89.2 g of cyclohexanone were added and heated to 80°C. After 30 minutes, the mixture was diluted to a solid content of 40% and reacted for an additional 3 hours. The obtained varnish had a hue of Gardner 2, a viscosity at 25°C of Z ₅ −Z ₆ , and a molecular weight distribution measured by the GPC method: Mn=17000, Mw=
43000, Mw/Mn=2.53. Comparative Example 1 Synthesized from 93 g (1.0 mol) of aniline, bisphenol A and epichlorohydrin, with epoxy equivalent
376 g (1.0 mol) of a 188 g/eq epoxy resin and 312.6 g of cyclohexanone were added and reacted at 120 to 140° C. with stirring for 16 hours. Solid content 60%, hue Gardner 2, viscosity UV at 25℃, molecular weight distribution measured by GPC method: Mn = 2800, Mw = 18000,
Mw/Mn=6.43. Comparative Example 2 94 g (1.0 mol) of benzylamine, 950 g (1.0 mol) of an epoxy resin synthesized from bisphenol A and epichlorohydrin and having an epoxy equivalent of 475 g/eq, and 696 g of methyl ethyl ketone were stirred and reacted at 60°C. The reaction was carried out for 24 hours with successive dilutions.
The obtained varnish had a solid content of 40%, a hue of Gardner 1, a viscosity of Y-Z at 25°C, and a molecular weight distribution measured by GPC method: Mn = 5900, Mw = 30500, Mw/
Mn=5.17. Comparative Example 3 Phenoxy resin synthesized from bisphenol A and epichlorohydrin (PKHH, UCC, USA)
Dissolve 40g in 60g of methyl ethyl ketone and make 40
% varnish was obtained. Hue Gardner 1, viscosity at 25℃ Z ₄ −Z ₅ , molecular weight distribution measured by GPC method is Mn
= 9500, Mw = 42200, Mw/Mn = 4.44. Application Example A one-component zinc-rich paint prepared using the resins obtained in the Examples and Comparative Examples through the following formulation and operation was barred onto a 0.8 x 70 x 150 m/m mild steel plate that had been sandblasted and degreased in advance. A coater was used to coat the film to a dry film thickness of approximately 30 microns. The coating film was tested after drying at 20°C for 7 days. One-component zinc-rich primer formulation polyhydroxypolyetheramine or phenoxy resin
15 parts Zinc dust (LS-2 manufactured by Mitsui Kinzoku Co., Ltd.) 84 parts Bentone #38 1 part Diluent solvent* Appropriate amount Solid content 66.7%, Pigment weight concentration 85% Dispersion was performed for 30 minutes using a paint conditioner. * Mixed system of toluene/celloacetate/IPA=50/30/20 [Table]

Claims (1)

[Claims] Two piperazine rings and two
1. A method for producing a piperazine ring-containing polyhydroxypolyether amine, which comprises reacting an organic amine containing a grade amine with a diepoxy compound in substantially equal moles of amino groups and epoxy groups or in a slight excess mole of amino groups.