JPS5859220A - Production of coating resin - Google Patents

Abstract

PURPOSE:To obtain a coating resin excellent in corrosion resistance, adhesion and impact resistance, by reacting a specified sec. diamine with a diepoxy compound in amounts such that the amount of amino groups is equimolar to or slightly excess over that of epoxy groups. CONSTITUTION:A piperazine ring-contaning polyhydroxy polyether amine is obtained by reacting a diepoxy compound with piperazine or an organic amine containing at least one piperazine ring and two sec. amine groups in the molecule, in amounts such that the amount of amino groups is equimolar to or slightly excess over that of epoxy groups. This polyether amine is typified by a compound of chemical formulaI, and depending upon a combination of the amine component and the epoxy component, the polyether polyamine has a more complicated and diversified chemical structure. As the organic amines used, there can be mentioned compound represented by formula II, wherein R<1>-R<8> are each H or a lower alkyl.

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, heat resistance, and mechanical properties.

Epoxy resins and epoxy-modified polyol resins have excellent adhesion to metals, corrosion resistance, etc., and are widely used as undercoat paints. However, in recent years, due to the rationalization of the painting process and the desire to save resources,
There is a growing trend towards omitting or reducing painting processes and improving workability, and there is an increasing demand for high-performance paints. Generally, epoxy resins that cure at room temperature are
In the case of zero or epoxy modified polyol resin, which requires an amine curing agent and is a two-part system, it also requires a polyisocyanate as a curing agent and is a two-part 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 can compensate for this shortcoming to some extent, but this system tends to have poor secondary adhesion because it is not crosslinked. Although phenoxy resin has better impact resistance than general epoxy, it still does not provide satisfactory secondary adhesion after impact resistance. In order to streamline the process, it is necessary for the pre-painted metal material to withstand strong deformation and impact during cutting and bending, and to maintain coating properties such as corrosion resistance of the processed parts.The present invention These materials essentially belong to the phenoxy type, but we are working diligently to provide a new coating material that fully compensates for the above drawbacks and has extremely excellent corrosion resistance, toughness, and adhesion, and IIC also has acupuncture impact properties. As a result of repeated research, the present invention has been completed, in which a specific secondary diamine described below is used as an amine component, and a difunctional di-boxy compound is used as an epoxy component.
A polyhydroxypolyetheramine is provided by reacting the amino group and the epoxy group in substantially equivalent amounts or in a small excess of the amino group.

The piperazine ring-containing polyhydroxy polyether amine of the present invention can be expressed as a typical chemical formula as follows.

Of course, due to the combination of the amine component and the epoxy component, a piperazine ring is introduced into the molecule of the polyhydroxy polyether amine of the invention, and the adhesion to the base metal is significantly improved by the action of nitrogen of this cyclic tertiary amine. be done.

Also, since it does not contain ester bonds in the molecule, it has excellent alkali resistance and water resistance. Furthermore, it is known that cyclic compounds have better heat resistance than linear compounds, and an 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 thought to be due to the fact that the reaction between the specific secondary amine and the epoxy group uniformly and smoothly increases the molecular weight, the molecular weight distribution is sharp, and there are few low molecular weight components. As a compound similar to the polyhydroxypolyetheramine of the present invention, a method for producing polyhydroxypolyetheramine by the reaction of a bifunctional engineered poxy compound and a primary monoamine was proposed (Japanese Patent Publication No. 3, Sho 3).
No. 5-11796, No. 36-1993, No. 51-18
No. 973), but polymerization by reaction of primary amine and epoxy is actually #'12 reaction color 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 between l,@amine and secondary amine with epoxy, and the reaction rate is 50 to 100 times that of primary amine and t12-class amine. Furthermore, the secondary amine produced by addition of the primary amine is substituted with an alkyl group derived from the amine, and this becomes a steric hindrance, significantly slowing down the addition reaction of the secondary amine to the epoxy. do. As a result, the polyhydroxypolyether amine obtained by the reaction of a jepoxy compound and a 1M amine has difficulty in increasing its molecular weight smoothly, has a wide molecular weight distribution, contains many low-molecular steels, and does not have self-forming properties by itself.
Since it is necessary to form a film using a crosslinking agent, it is naturally inferior in impact resistance to 4I#. 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 rate, and therefore the molecular weight distribution It is possible to make sharp polymers. Bisphenol A mentioned earlier
Although it is possible to create a relatively sharp molecular weight distribution using polyhydroxypolyether synthesized from and epichlorohydrin, this polymer system requires a long reaction time of 25 to 30 hours because it is polymerized using an alkali catalyst. If a highly successful alkali catalyst is used with the aim of shortening the reaction time, it is not preferable to use a branched polymer due to the reaction between pendant secondary hydroxyl groups and epoxy. In addition, this system requires a great deal of labor, time and energy to remove the alkali catalyst, which increases production costs. Moreover, in Japanese Patent Publication No. 53-20080, nitrogen-containing heterocyclic compounds such as 2,5-piperadione, 2,6-piperadione, 2,4-imidazolidione, 5,6-sihydrouracil, barbylic acid, etc. and epoxy compounds are disclosed. A method for producing thermoplastic resins for coating and molding is disclosed. All of the above nitrogen-containing heterocyclic compounds have a carbonyl group in the ring, and the carbonyl group is a carbon atom adjacent to the carbonyl Fi element (secondary amine). In other words -C0
As represented by N)I-, the hydrogen bonded to this nitrogen has properties similar to so-called amide hydrogen, and its reactivity with epoxy groups is significantly worse than that of general 2Mt amine hydrogen. In fact, all of the examples described in Special Publication No. 53-20080 use a catalyst (quaternary ammonium),
Moreover, the reaction time is 35 to 60 hours at 4,100 to 110°C, and the productivity is extremely low. A poorly engineered zero-pronged catalyst is used, and the burrs are not removed, resulting in performance problems. On the contrary, the process according to the invention can be used only with essentially linear polymers,
The reaction time is 5 to 6 hours, which is sufficient, and the removal of the catalyst is also fast.It is superior to conventional polymer systems in all aspects.
The specific secondary diamine used in the present invention has the general formula: The secondary diamine may be used alone or as a mixed amine. Alkyl substitution on the piperazine ring is allowed as long as it is lower.

The compound of formula (2) is synthesized from N-aminoethylpiperazine and a dibasic acid or dibasic acid lower alkyl ester through an amidation reaction. Dibasic acids or their esters that can be used include adipic acid, cepatic 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 polyester with terminal carboxylic acid. Oligomers etc. can be used.

In addition, as the jepoxy compound used in the present invention, Fi2
It can be obtained by reacting phephenol with pyhalohydrin in a conventional manner. As dihydric phenol, 1
Examples of mononuclear dihydric phenols having 2 aromatic nuclei and poly[2111 phenols having 2 or more aromatic nuclei; Lauresorcinol, hydroquinone, 2.-POMOJ'4)' quinone, pyrocatechol, 70roglucinol, l,5-dihydroxynaphthalene, 2.7-dihydroxynaphthalene, 2,6-
Examples include dihydroxynaphthalene. Examples of polynuclear dihydric phenols include various bis(hydroxyphenyl) alkanes such as 2,2-bis-(4-hydroxyphenyl)propane (bisphenol A), and Fi4, 4'-dihydroxybiphenyl. or various di(hydroxyphenyl) sulfones represented by bis-(4-hydroxyphenyl) sulfone, or various di(hydroxyphenyl)s represented by bis(4-hydroxyphenyl) ether. Examples include ether. Furthermore 1,1-
Bis(4-hydroxyphenyl)-2-phenylethane, 1,3.3-)limethyl-1-(4-hydroxyphenyl)-6-hydroxyindan, 2.4-bis(p-
Hydroxyphenyl)-4-methylpentane can also be used as the 710 human sin, for example, epicurhydrin, epibromohydrin, 1,2-epoxy-2-
Methyl-3-10 propane, 1,2-epoxy-2-
Examples of catalysts that promote the reaction between the epihalohydrin and dihydric phenol include Lewis acids such as trifluoride, stannic chloride, zinc chloride, and ferric chloride. , acidic catalysts such as derivatives exhibiting these activities (e.g. trifluoride salt-ether complex compounds) or mixtures thereof, alkali metal hydroxides, alkali metal alcolades, tertiary amine compounds, quaternary ammonium Examples include basic catalysts such as compounds or mixtures thereof. The epoxy compound is produced simultaneously with this reaction, or the epoxy compound is produced by ring-closing the polyhahydrin ether produced as a result of the reaction into dehydrogenation. As the basic compound used in this de-N-hydrogenation reaction, alkali metal oxides, alkali metal aluminates, etc. are used. These catalysts and basic compounds can be used as they are or as a solution in an appropriate inorganic or organic solvent.

Therefore, the method for producing the piperazine ring-containing polyhydroxypolyetheramine of the present invention can be carried out by the following method. That is, the diamine and the epoxy compound are charged in substantially equal moles or in a small excess of the diamine, and if desired, A ketone type, ether type, ester type, phenol type, aromatic hydrocarbon/alcohol mixed type, etc. may be used as the solvent. The thus obtained piperazine ring-containing polyhydroxypolyetheramine can be used alone, but it can also be used in combination with epoxy resins, urea melamine resins, polyurethane resins, polyurethane prepolymers, phenolic resins,
1 selected from alkyd resin, polyester resin, etc.
A species or two or more kinds of resins can be contained within a desired objective range. In addition, diluents, dyes, pigments,
It is also possible to contain fillers, plasticizers, crosslinking agents, etc. The effect of the present invention is that the resulting piperazine-containing polyhydroxypolyetheramine has a high molecular weight, so it can be used as a lacquer-type paint, and can also be used in combination with a crosslinking resin to create a base paint for pre-coated metals, a wire coating paint, a magnetic paint, etc. It is also useful as paint for cans, 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 adipine were placed in a 1 l separable flask, and dehydrated while purging with nitrogen gas at 200°C. Heated for 4 hours. Collected 18 pieces of real fishing,
Diamine containing two piperazine rings per molecule (A-1
) was synthesized. This product was pale yellow and waxy. This diamine (A-1) 184 f (0.5 mol) [, synthesized from bisphenol A and epichlorohydrin, epoxy resin 18 with an epoxy equivalent of 188 p/eq
8y (0.5 mol) and 93 g of methyl ethyl ketone as a solvent were added and reacted at 60°C. After 30 minutes, 100y of methyl ethyl ketone was added. Similarly, the mixture was reacted at 60° C. for 5 hours while being serially diluted. The final solid content concentration WL is 4
It was 0chi. Hue Gardner 1.2 on the resulting varnish
．． The viscosity at 5°C is Z6, and the molecular weight distribution measured by the gel permeation method (hereinafter referred to as GPC) is: number average molecular weight (Mn) 31,000, weight average molecular weight (Mw) 96.
,000, variance*Mw/M n=3.1.

Example 2゜Diamine (A-1) 184f (0
, 5 mol) #C A solid epoxy resin synthesized from bisphenol A and epichlorohydrin, 648.79 (0,499 mol) of a solid epoxy resin with an epoxy equivalent of 5 sOy/eq and 555 y of methyl ethyl ketone were added and reacted at 50 °C to give a zero thickening solution. After 6 hours, the solid content was 3Fl.
& got varnish. The molecule 1 distribution measured by GPC method is M
n=28.00 'Os Mw=78,000, M
w/Mn = 2.78.

Example 3゜N'-7mi/ :X f le Herashif 1'3 o'
, s part (1,01) was amidated at 220°C for 3 hours to exude diamine (A-2).
'2) was synthesized from as, sy, bisphenol A and epichlorohydrin, and an epoxy resin 95P1cyclo of 1i475y/eQ per epoxy was added and heated to 80°C. After 30 minutes, the mixture was diluted to a solid content of 4° and reacted for an additional 3 hours. The varnish obtained had a hue Gardner of 2.25 DEG C. and a viscosity of 25-2. ,G
The molecular weight distribution measured by the PC method is Mn = 17,000
, Mw=43,000. Mw/Mn=2.53.

Example 4 Piperazine 86p (1.0 mol), synthesized from bisphenol A and epichlorohydrin, epoxy equivalent 9sO
P/eq epoxy resin 1900y and cellosolve acetate) 3310y were stirred and heated at 50°C. After 3 hours, the mixture was diluted with ethylceronlube to give a solid content of 25%. A varnish was obtained by reacting at the same temperature for 3 hours.The hue of this product was less than Gardner 1, viscosity at 25℃ff1tiU, GPC
Molecular weight distribution t measured by method; j Mn = 19.0
0'0, Mw = 52,000, Mw/Mn=2.
It was 74.

Example 5゜Same as Example 4, the solvent composition was changed to ethylcerone 7, methyl cellosolve 251) toluene 34, and butanol 34.
- Reacted in the same manner except for using a mixed system with a solid content of 40
Got arrogant varnish. The hue of this one is Gardner 1.25
Viscosity at °C〉Z6.

Example 6 Epoxy resin 103.89 (0.4 mol) synthesized from piperazine 86y (1.0 mol), polyethylene glycol and epichlorohydrin and has an epoxy equivalent of 173 y/eQ, and an epoxy resin synthesized from bisphenol A and epichlorohydrin and has an epoxy equivalent of 188 y/eQ. eq epoxy resin 26
3.2 y (0.7 mol) and methyl ethyl ketone 1
94y was stirred at 50° C. for 4 hours, diluted to a solid content of 40%, and reacted at the same temperature for 4 hours to obtain a varnish. Hue Gardner 1 or less, Teno viscosity 22-2 at 25℃
．． , the molecular weight distribution measured by GPC method is Mn=14,0
Comparative Example 1 Aniline (13y (1.0 mol), synthesized from bisphenol A and epichlorohydrin, epoxy equivalent: 188
y/eQ epoxy resin 376y (1.0 mol) and cyclohexanone 312.67 were added and reacted for 16 hours with stirring at 120 to 140°C. The solid content is 60 cm, the color is Gardner, the viscosity is UV at 2.25°C, and the molecular weight distribution measured by GPC is Mn = 2,800. Mw=18,0
00, Mw/Mn=6.43. .

Comparative Example 2 Epoxy tree 1 synthesized from benzylamine 94 f (1.0 mol), bisphenol A and epichlorohydrin and having an epoxy equivalent of 475 y/eq] Fr 950 f (
1.0 mol) and methyl ethyl ketone 696y were stirred and reacted at 60°C. The reaction was carried out for 24 hours with successive dilutions. The resulting varnish had a solid content of 40'1 and a hue of Gardner of 1.
．． 25°C tenor viscosity Y-Z, molecular weight distribution measured by GPC method: Mn = 5,900, Mw = 30.500
, My/Mn = 5.17.

Comparative Example 3 A phenoxy resin (PKHH, UCC, USA) 40F synthesized from bisphenol A and epichlorohydrin was dissolved in 60F of methyl ethyl ketone to obtain a 40F varnish. Hue Gardner 1. Viscosity at 25°C 24-2. ,G
Molecular weight distribution measured by PC method #iMn = 9,50
0, Mw=42,200, Mw/Mn=4.4
4.0 Application Examples The resins obtained in the Examples and Comparative Examples were prepared through the following formulations and operations - A liquid zinc-rich undercoat was pre-sandblasted and degreased to give a 0.8 x 7
A dry film of about 30 microns was coated on a 0 x 150 m/rn mild steel plate using a bar coater. Test of coating film F: Tested after drying at 120°C for 7 days.

Formula of one-component zinc-rich primer 15 parts polyhydroxy polyether amine or phenoxy resin
38 1 part diluent solvent 2
Solid content: 66.796, Pigment weight concentration: 85% O x Mixed system of toluene/celloacetate/IPA = 50/30/20 for 30 minutes with Dispersa paint conditioner

Claims (1)

[Claims] Piperazine or an organic amine containing at least one piperazine ring and two secondary amines in one molecule and a jepoxy compound in which the amino group and the epoxy group are substantially equal moles or a small excess mole of amino groups. A method for producing a coating resin characterized by reacting with.