JPS5869265A - Paint composition - Google Patents

Abstract

PURPOSE:To provide a resin compsn. for paints, which has corrosion resistance and adhesion to metal, containing a water dispersion of a specified chelate- reactive epoxy resin and an active org. hardener. CONSTITUTION:A paint compsn. contains a water dispersion of a precondensate (A) derived from an epoxy resin having an epoxy equivalent of pref. 200-1,000 and a polyhydric alcohol ester of a polyhydric phenolic carboxylic acid contg. neighboring hydroxyl groups, such as one derived from glycerol of the formula and proto-catechuic acid, and/or a polynuclear polyhydric phenol contg. neighboring hydroxyl groups, such as a condensate of formal in with pyrogallol, and an active org. hardener (B) for said epoxy resin, such as an aliph. polyamine or a carboxylic acid. This compsn. exhibits excellent corrosion esistance and adhesion to steel sheets in which rust is not appreciable, derusted steel sheets, rusting steel sheets, galvanized sheet, aluminum, stainless steel, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel water-dispersible coating composition for corrosion protection of metals. More specifically, it relates to an aqueous anti-corrosion coating composition comprising an aqueous dispersion of a specific chelate-reactive epoxy resin and an active organic curing agent. In particular, rust-free steel plates, rusted steel plates, rusted steel plates, steel plates with inadequate surface treatment, galvanized steel plates, and aluminum.

The present invention relates to a coating composition that has excellent adhesion and corrosion resistance to stainless steel and the like.

Conventional water-dispersed epoxy resin paints are significantly inferior in adhesion and especially in corrosion resistance compared to solvent-based epoxy resin paints, and are used for corrosion-resistant pipes as a material for protecting nine metals. It cannot be used as an I fee.
The main application is mastic paints related to main rib parts.

An object of the present invention is to provide a resin composition for a water-dispersed epoxy resin paint that has excellent adhesion to metals and corrosion resistance.

The coating composition of the present invention contains (4) an epoxy resin (A-11 and a polyhydric alcohol ester of a polyhydric phenol carboxylic acid having an adjacent hydroxyl group (M-2-1)) as an essential component.
and/or polyhydric phenols having adjacent hydroxyl groups (A
-2-2) and (B) an active organic curing agent for epoxy resin.

Precondensate (modified epoxy resin) which is a component of the composition of the present invention Fi epoxy resin (A-11 and polyhydric alcohol ester of polyhydric phenol carboxylic acid having adjacent hydroxyl groups (mu-2-13 and h/or ti Obtained by heat-treating a polynuclear polyhydric phenol (mu-2-2) containing adjacent hydroxyl groups in the presence or absence of a solvent and in the presence or absence of a catalyst in a proportion in which epoxy groups remain. There is no limitation to ti411 as the heating temperature, but it is usually 1, which does not cause decomposition of the epoxy resin and completes the reaction in an appropriate time.
It is best to carry out at a temperature of 00 to 200°C. During this reaction, a tertiary amine, a 4I & ammonium salt, a quaternary phosphonium salt, an amine hydrochloride, etc. can be used as a catalyst.

The epoxy resin (Mu-1) used here has the formula
Any number of substituted or unsubstituted glycidyl ether groups represented by the formula %) can be used, such as those having more than one substituted or unsubstituted glycidyl ether group in the molecule, and there is no restriction on the epoxy equivalent, but it is preferable. has an epoxy equivalent of 200 to 10,008! degree is better.

Polyhydric alcohol ester of polyhydric phenol carboxylic acid containing adjacent hydroxyl groups in the molecule used in the present invention (mu-2-
1) includes the following:

That is, polyhydric alcohol components include ethylene glycol, propylene glycol, butylene glycol, 1.6
- Diols such as hexanediol, triols such as glycerin and trimethylolpropane, polyols with a valence of 4 or more such as pentaerythritol, sorbitol, glucose, etc. can be used, and as the i11 hydroxyl group-containing polyhydric phenol carboxylic acid component, Catechol-3-carboxylic acid, catechol-4-carvone @ (protocatechuic acid), gallic acid (3,4,5-trioxybenzoic acid)
, m-digallic acid, pyrogal-4-carboxylic acid, pyrogallol-4,6-dicarboxylic acid, tannic acid, etc. can be used, and the typical structure of the ester is Fi, for example, in the case of an ester of glycerin and protocatechuic acid. can be,
In addition to this, it is thought that higher-order condensates are also included.

[ You can give it 2.

Polyhydric phenol with adjacent hydroxyl groups used in the present invention (
The following four examples are preferable as mu-2-2). formalin condensate of catechol, formalin condensate of catechol-3 (or 4)-carboxylic acid (or its ester), formalin condensate of pyrogallol,
Formalin condensate of pyrogallol-4-carboxylic acid (or ester of TLT), formalin condensate of pyrogallol-4,6-dicarboxylic acid (or ester thereof),
S, 4.5-)! Formalin condensate of J oxybenzoic acid (or its ester), tannic acid (or its ester) or its formalin condensate, formalin condensate of urushiol. 9 When polyhydric phenol is condensed with formalin, it is mixed with mononuclear phenol such as phenol, cresol, hydroquinone, and salicylic acid.
good. Polyhydric alcohol ester of polyhydric phenol carboxylic acid A (A-・2-1) and /1! The reaction ratio of the M polynuclear polyhydric phenol (Mu-2-2) and the epoxy resin (Mu-1) is an average of 0.05 mol or more per molecule of stopped precondensation, preferably q 0.1 mol or more. The ratio should be such that the polyhydric phenol carboxylic acid polyhydric alcohol ester and/or polynuclear polyhydric phenol are reacted and contained, and the epoxy equivalent of the obtained precondensate is 3000 or less. It is better.

The thus obtained precondensate can be easily made into an aqueous dispersion by using known nonionic, anionic or cationic surfactants.

As the active organic curing agent, all curing agents for ordinary epoxy resin coatings can be used, such as aliphatic polyamines, aromatic modified polyamines, alicyclic modified polyamines, polyamides, amino resins, Examples include carboxylic acids.

Furthermore, the composition of the present invention may contain other epoxy resins, diluents, PM substances, solvents, coloring pigments, antirust pigments, fillers, and other additives, if necessary.

The coating composition of the present invention can be dried naturally to form a coating film, but if necessary, the desired coating film can also be obtained by forced drying by heating or the like.

Hereinafter, the present invention will be explained in detail with reference to Examples.

Note that the weight is based on part #'1 in the example.

Example 1 Triester of protocatechuic acid in glycerin (Mw=
500,120 parts, 100 parts of bisphenol A diglycidyl ether (epoxy equivalent = 190) and 0.15 parts of dimethylbenzylamine as a catalyst were added, and the reaction was continued at 150° C. for 3 hours with stirring.

The product thus obtained in L7 is referred to as a precondensate [Summer].

Precondensate [11,100 parts and Adekanol NK-511
(Asahi Denka Kogyo Co., Ltd., anionic surfactant, 30 aqueous solution) was added to the mixture and stirred using a homomixer. Next, 54 parts of water are gradually added and stirring is continued for 30 minutes. A curing agent and a polyamide (amine value = 3.4) were added to 100 parts of the obtained epoxy emulsion (solid content = 60%).
Q) Add 25 parts of this blended resin to a steel plate (JIS G 31
41) was applied to a film thickness of 20 μm, and after curing for one week, a comparative wiping test was conducted to compare the film performance as shown in Table IK. <Better than the comparative example.

Example 2 and 200 parts of sphenome diglycidyl ether (epoxy equivalent = 280) and 5.5 parts of trimethylolpropane.
4.5- ) triester of lyoxybenzoic acid (Mw=
590) and 20 parts of ethyl cellosolve were added and the reaction was continued at 150°C for 8 hours with stirring.

The nine products obtained in this manner are referred to as Preliminary Compound 1 [n].

Precondensate [II] 100 parts and Ryodecanol NK-s
Add 11 parts of the mixture and stir with a homomixer.

Next, 54 parts of water was gradually added and stirring was continued for 50 minutes. Obtained epoxy emulsion (solid content -42%) 100
The modified aromatic amine decano-1-donor IH-551 (amine value = 280
, trade name (manufactured by Asahi Denka Kogyo Co., Ltd.) was added, and a coated board was made using this blended resin in the same manner as in Example 1. As a result of comparison, it was found that the adhesion and corrosion resistance were superior to the comparative example in terms of adhesion and corrosion resistance. No.

Example 3 150 parts of bisphenol AI diglycidyl ether (epoxy equivalent = 190), 50 parts of bisphenol A propylene oxide-added eyelid diglycidyl ether (epoxy equivalent = !540), 50 parts of m-digallic acid ester of glucose, cellosolve 50 parts of acetate and 0.5 part of triethylamine as a catalyst were added, and the reaction was continued at 140°C for 6 hours.

The product thus obtained is referred to as a precondensate (I[]).

Precondensate [■] 100 parts and Adekanol 961S (Asahi Denka Kogyo C Co., Ltd.), nonionic surfactant, 701J1
Add 20 parts of aqueous solution and stir with a homomixer. Next, gradually add 53 parts of water and wait 30 minutes! Continue stirring.

Obtained epoxy emulsion (hard content = 60 t) 1
Add 6 parts of Adeka Hardener IH-220 (amine value = 375, manufactured by Asahi Denka Kogyo Co., Ltd.) as a hardening agent to 2.
IS G! 1141), film thickness 200μ 7.1
After curing at room temperature for a week, a comparative test of coating film performance as shown in Table 1 was carried out, and the results showed that both adhesion and corrosion resistance were significantly superior to the comparative example.

Example 4 150 parts of bisphenol F diglycidyl ether (epoxy equivalent = 240) and 50 parts of pyrogallol-4-carboxylic acid diester of diethylene glycol, Φ to cyclo
20 parts of Sanone and 0.3 parts of triethanolamine are added and the reaction is continued at 155° C. for 8 hours without stirring.

The product thus obtained is designated as precondensate [IV].

Precondensate [IV] 100 parts and Adekanol 961B
Add 15 parts and stir with a homomixer. Then water 65
Gradually add parts! Continue stirring for IO minutes.

Obtained 9 epoxy emulsions (55 bags per hard layer) 100
15 parts of polyamide (amine value = 20,0) was added as an epoxy resin curing agent to the epoxy resin curing agent, and 1 part of the blended resin was applied to a rusted steel plate (1-year Sekihogai Bakuro (7, steel plate with floating rust removed). , with a film thickness of 200 voices, and one
After curing at II temperature, a comparative test of coating film performance as shown in Table 1 was carried out, and the result was that both adhesion and corrosion resistance were excellent and superior to the comparative example.

Example 5 100 parts of bisphenol A diglycidyl ether (epoxy equivalent = 190), 20 parts of a formalin condensate of catechol (molecular weight = 450), 10 parts of xylene, and 0.2 parts of triethylamine as a catalyst were added, and the mixture was mixed with stirring.
Continue the reaction at 40°C to 150°C for 6 hours.

The product thus obtained is referred to as precondensate [v].

Precondensate [100 parts of Vl and Adekanol MK-51
Add 155 parts and stir with a homomixer.

Next, 85 parts of water was gradually added and stirring was continued for 50 minutes. The obtained epoxy emulsion (solid star fraction = 501 / 100
polyamide as a curing agent (amine value, = 2
40) 5 m parts was added, and this blended resin was applied to a steel plate (G 5141 from J) to a film thickness of 150μ, and cured for one week for home appliances.As a result of comparison in the same manner as Example 1, the adhesion and corrosion resistance were better than that of the comparative example. He was excellent, finishing in 4th place.

Example 6 Formalin condensation of 150 parts of bisphenol A diglycidyl ether (epoxy equivalent = 240), diglycidyl ether of bisphenol A propylene oxide adduct (epoxy equivalent = 340), and m-digallic acid methyl ester - (average 45 parts (molecular weight = 750) and 0.7 parts of triethylamine as a catalyst were added, and the reaction was continued at 150°C to 140'C for 10 hours with stirring.

Preparation of the desired product in this way [11m]
shall be.

9 parts of Adekanol per 100 parts of precondensate (Vl)
418, and stirred with a homomixer. Next, 70 parts of water was gradually added and stirring was continued for 1 hour.

Obtained 9 epoxy emulsion (solid content = 60) 1
00 parts, 15 parts of modified aliphatic amine Adeka Hardener In-218 (amine value = S a O1, trade name manufactured by Asahi Denka Kogyo Co., Ltd.) was added as a hardening agent, and the same procedure as in Example 1 was carried out using this blended resin. As a result of making painted plates and comparing them, it was found that both pipe adhesion and corrosion resistance were significantly superior to the comparative example.
Example 1 100 parts of unmodified bisphenol A diglycidyl ether (epoxy equivalent = 190) and Adekanol NK-5
Add 1150 parts and stir with a homomixer. Next, 54 parts of water was gradually added and stirring was continued for 30 minutes. 50 parts of polyamide (amine value = 340) was added as a hardening agent to 100 parts of the obtained epoxy emulsion (solid lid part 2 601), and this blended resin was applied to a steel plate (JIS G!5141).
A coated plate is prepared by applying the coating to a film thickness of 200 μm and curing at room temperature for one week.

Comparative Example 2 Unmodified bisphenol A diglycidyl ether [epoxy equivalent = 280) 1001IS and Adekanol NK
-51150 parts were added and stirred using a homomixer. Next, 54 parts of water was gradually added, and stirring for the IsO portion was continued. The obtained epoxy emulsion M ([1!11 min=6o*)
ADEKA HARDENER ZM- as a hardening agent for 1OO@
A painted board was prepared in the same manner as in Comparative Example 1 by adding s51zs@.

Comparative Example 3 754 g of unmodified bisphenol A diglycidyl ether (epoxy equivalent ≠ 190), 25 parts diglycidyl ether of bisphenol A propylene oxide adduct (epoxy equivalent = 340), and 9618 adecanol.
Add 20 parts and stir with a homomixer. Then water 70
1 part and continue stirring for 50 minutes. Obtained epoxy emulsion W (1ffi! 111 minutes = 4016) 100s
K vs. t,”r, Hardener Adeka Hardener-In-2209
A coated plate was prepared in the same manner as in Comparative Example 1.

Comparison Example 4 100 parts of diglycidyl ether of bisphenol 1 (epoxy equivalent = 240) and Adekanol 961B 20
of the mixture and stir with a homomixer. Next, 90 parts of water was gradually added and stirring was continued for 50 minutes. 20 g of the hardening agent Boria': )' (7 inch value = 200) was added to too much of the obtained epoxy emulsion (solid content = 55 pieces), and this blended resin was applied to a rusted steel plate in the same manner as in Example 4. The coating was applied to a film thickness of 200 μm and the temperature was reduced to 100%.

Table 1 shows the coating film performance test results of the coated plates prepared in Examples 1 to 6 and Comparative Examples 1 to 4.

Claims (1)

[Scope of Claims] As essential constituents, (4) an epoxy resin (Mu-1) and a polyhydric alcohol ester of polyhydric phenol carboxylic acid having adjacent hydroxyl groups (
A coating composition containing an aqueous dispersion of a precondensate with Mu-2-1) and/or a polynuclear polyhydric phenol having adjacent hydroxyl groups (Mu-2-2), and 俤) an active organic curing agent for epoxy resin. thing.