JPH05202334A - Epoxy resin coating composition - Google Patents

Abstract

PURPOSE:To provide an epoxy resin coating composition having excellent thixotropic property. CONSTITUTION:A solventless or low-solvent type epoxy resin coating (EP) is incorporated with a thixotropic agent consisting of a pregel (PG) produced by reacting a methylated benzaldehyde with sorbitol at a molar ratio of 2:1 and dissolving the obtained di(methylbenzylidene)sorbitol (MD) in a liquid constituent component (C) of the epoxy resin coating (EP). The liquid constituent component is liquid epoxy resin, reactive diluent, liquid modifier, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a solventless or low solvent type epoxy resin coating composition having excellent thixotropy.

[0002]

2. Description of the Related Art Epoxy resin paints are widely used as anticorrosion paints. Epoxy resin paints used to be solvent-based in the past, but now they are solvent-free or are shifting to water-based systems. Of these, the present invention relates to a solventless or low solvent type epoxy resin paint.

In general, non-aqueous paints such as epoxy resin paints often contain a thixotropic agent for the purpose of preventing sagging or thickening.

JP-A-2-233772 describes that 0.05 to 5 parts by weight of a coupling agent having a functional group, and a functional group that reacts with the functional group of the coupling agent, relative to 100 parts by weight of a film-forming resin. Inorganic fibrous anti-sagging agent 0.5
˜5 parts by weight, 0.01 to 5 parts by weight of an organic fibrous anti-sagging agent having a functional group that reacts with the functional group of the coupling agent, and a fine powder pigment having an average primary particle size of 0.1 μm or less 0.5
Solventless clear coating compositions containing from 10 to 10 parts by weight are shown. Here, the coating film-forming resin is a liquid epoxy resin, an acrylic resin, a polyester resin, or the like, the inorganic fibrous anti-sagging agent is asbestos having a hydroxyl group on the surface, and the organic fibrous material is high. Examples thereof include molecular weight polycarboxylic acids (metal salts of castor oil polymers or those neutralized with N-containing organic compounds such as amines). In the description of the prior art in the publication, asbestos, fine-grained silicic acid anhydride, polycarboxylic acid, castor oil derivative, polyamide wax, etc. have been known as typical examples of thick film coating anti-sagging agents. There is a statement that it has been done.

Japanese Unexamined Patent Publication No. 63-235381 discloses C
₃ -C ₄ straight chain and a mixture of saturated fatty acids and 12-hydroxystearic acid, ethylene diamine, or fatty acid amide obtained by reacting hexamethylene diamine (A)
And a mixture of C ₆ -C ₁₂ straight chain saturated fatty acids and 12-hydroxystearic acid, ethylenediamine,
A dripping preventive agent for non-aqueous paints, which is composed of a fatty acid amide (B) obtained by reacting with hexamethylenediamine or xylylenediamine, is shown.The dripping preventive agent is tar epoxy paint, tar urethane paint, pure epoxy. It is said to be applicable to paints, polyurethane paints, chlorinated rubber paints, acrylic paints, alkyd (modified) paints, etc. In the description of the prior art of the same publication, it is stated that the anti-dripping agents conventionally used in non-aqueous paints include montmorillonite derivatives, hydrogenated castor oil, oxidized polyethylene wax, metal soap, etc. Has been.

In JP-A-61-97375, a film-forming component comprising a hydroxy group-containing resin such as an acrylic resin or a polyester resin and an alcohol-modified amino resin is used, and as a sag controlling agent, aniline and an aliphatic diisocyanate are used. A thermosetting coating composition capable of coating a thick film prepared by blending a reactant (C) and a mixture of a reactant (D) of an oxygen-containing primary monoamine and an aliphatic diisocyanate is shown. In the description of the prior art of the publication, it is said that calcium carbonate, organic bentonite, hydrophobic silica, organic polyamide wax, polyethylene wax, a compound having a urea bond, etc. have been conventionally used as a sag controlling agent for coating materials. There is a description.

[0007] In the section of the conventional method described in JP-A-56-163146, Chikushin (Baker Caster Oil Co., Ltd.) is used as a method for preventing sedimentation of an inorganic filler in a liquid composition containing the inorganic filler. , Disparlon (Kusumoto Kasei Co., Ltd.), Gelol (New Japan Rika Co., Ltd.), Gelton (Shiraishi Calcium Co., Ltd.), and other organic thixotropic agents such as colloidal silica have been used.

Japanese Patent Application Laid-Open No. 48-83 relating to the applicant's application
No. 98 discloses a thixotropic agent obtained by reacting polyisocyanates with an amide derivative obtained by reacting 12-hydroxystearic acid with polyamines. In the description of the conventional method of the publication, as the conventional thixotropic agent, fine powdery silicic acid anhydride is generally used, and it is described that saturated fatty acid ester or amide type is also used. is there.

Japanese Unexamined Patent Publication (Kokai) No. 51-67395 discloses a thixotropic polyurethane composition in which 1,3,2,4,5,6-tribenzylidene sorbitol is mixed with a polyurethane prepolymer. The description of the conventional method in the publication describes that fine powder silica, asbestos, organic bentonite, benzylidene sorbitol and the like have been conventionally used as the organic thixotropic agent.

From 497 of "Handbook of color materials engineering, published by Asakura Shoten Co., Ltd., date of issue: November 25, 1989"
On page 500, as a non-aqueous thixotropic agent, synthetic fine powder silica,
It has been shown that organic bentonite, fine particle treated calcium carbonate, hydrogenated castor oil, metal soap, polyamide wax, polyethylene oxide, vegetable oil-based polymerized oil, surfactant, etc. are used. Issued by CMC Inc., date of issue: July 31, 1989
On page 100 of "Sun", in addition to the above, dextrin fatty acid ester and dibenzylidene sorbitol are also listed as thickening and anti-sagging agents for non-aqueous systems.

[0011]

As described above, various types of thixotropic agents for non-aqueous paints have been conventionally used or proposed. Among these, the most versatile one is fine particle silicic acid anhydride, and fatty acid amide, hydrogenated castor oil, organic bentonite, etc. are also put to practical use.

However, when thixotropic properties are imparted to solvent-free or low-solvent type epoxy resin coatings, these thixotropic agents do not always give satisfactory thixotropy. For example, the addition of particulate silicic acid anhydride lacks the thixotropic effect, and fatty acid amides, hydrogenated castor oil, dibenzylidene sorbitol, organic bentonite, etc. also lack the thixotropic effect. When the thixotropic effect is insufficient, it is difficult to form a thick film during coating.

The present inventors, while searching for new thixotropic agents to replace the above-mentioned thixotropic agents having such limitations, give excellent thixotropy to solvent-free or low-solvent type epoxy resin coatings. The inventors have succeeded in finding a thixotropic agent and have completed the present invention. That is, the object of the present invention is to provide an epoxy resin coating composition having excellent thixotropy.

[0014]

The epoxy resin coating composition of the present invention is a solventless or low solvent type epoxy resin coating (E
P), as a thixotropic agent, di (methylbenzylidene) sorbitol (MD), which is a reaction product of methylated benzaldecht and sorbitol in a molar ratio of 2: 1, is epoxy resin paint.
Pregel (PG) pre-dissolved in liquid component (C) in (EP)
Is included.

The present invention will be described in detail below.

Solventless or low solvent type epoxy resin paint (E
As P), liquid epoxy resins such as pure epoxy resins including bisphenol A type epoxy resin and bisphenol F type, tar epoxy resin, modified epoxy resin, and aliphatic polyamines (ethylenediamine, diethylenetriamine, etc.), amine adducts (amines). To an epoxy resin), a polyamide (a reaction of amine with dimer acid), a polyamide adduct (a dimer acid of amine and an epoxy resin adduct), and other hardeners and other hardeners The following are preferably used.

The above liquid epoxy resin may be mixed with a reactive diluent such as allyl glycidyl ether, phenyl glycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, epichlorohydrin and styrene oxide. Petroleum resin, tar, coumarone-indene resin,
A modifying component such as creosote oil may be blended. It is preferable not to add a solvent, but a small amount may be added.

In the present invention, the solvent-free or low-solvent type epoxy resin coating material (EP) is used as a thixotropic agent in a molar ratio of methylated benzaldecht and sorbitol of 2: 1.
Reaction product of di (methylbenzylidene) sorbitol
Add (MD).

This di (methylbenzylidene) sorbitol (MD) is a reaction product of two molecules of methylated benzaldecht with four of six OH groups of one molecule of sorbitol, and the main products are as follows. It is believed to be the compound represented by Chemical formula 1 A commercially available product of di (methylbenzylidene) sorbitol (MD) is, for example, "Gel All MD" manufactured by Shin Nippon Rika Co., Ltd.

[0020]

[Chemical 1]

The above-mentioned di (methylbenzylidene) sorbitol (MD) is a solventless or low solvent type epoxy resin in the form of pregel (PG) prepared by previously dissolving it in the liquid constituent (C) in the epoxy resin coating (EP). It is necessary to add it to the paint (EP) and mix it, and the desired thixotropy cannot be obtained simply by adding the powder of di (methylbenzylidene) sorbitol to the solventless or low solvent type epoxy resin paint. Examples of the liquid constituent component (C) include epoxy resin, reactive diluent, liquid modifying component, liquid non-reactive component and the like.

The di (methylbenzylidene) sorbitol (MD) is added in an amount of 0.1 to 5% by weight, usually 0.1 to 3% by weight, and particularly 0.2 to the solventless or low solvent type epoxy resin coating (EP). It is desirable to set the amount to 2% by weight. If the added amount is too small, the desired thixotropic property cannot be obtained. On the other hand, if the added amount is too large, the viscosity becomes excessive and the coatability is impaired.

In the composition of the present invention, in addition to the above components,
Additives such as a filler, a defoaming agent, a leveling agent, a color separation preventing agent, and a coloring agent can be appropriately mixed.

[0024]

[Function] In a coating composition using a solventless or low solvent type epoxy resin (EP), the above di (methylbenzylidene) sorbitol (MD) is a similar compound such as dibenzylidene sorbitol or tribenzylidene sorbitol. It shows a rock-shaking effect that is far superior to. In addition, such an effect is obtained by adding di (methylbenzylidene) sorbitol (MD) to the epoxy resin coating (EP) in the form of pregel (PG) in which the liquid constituent (C) in the epoxy resin coating (EP) is dissolved in advance. If it is done, it will be played for the first time.

[0025]

EXAMPLES The present invention will be further described with reference to examples. Hereinafter, "part" and "%" are shown on a weight basis.

Example 1 The following were prepared as thixotropic agents for non-aqueous paints. (C-1) Di (methylbenzylidene) sorbitol (reaction product of methylated benzaldecht and sorbitol in a molar ratio of 2: 1, "Gelol MD" manufactured by Shin Nippon Rika Co., Ltd.) (C-2) dibenzylidene sorbitol (“Gelol D” manufactured by Shin Nippon Rika Co., Ltd.) (C-3) Tribenzylidene sorbitol (“Gelol T” manufactured by Shin Nippon Rika Co., Ltd.) (C-4) N-lauroyl-L-glutamic acid dibutylamide (Ajinomoto "GP-1" made by a corporation)

A coating composition was prepared with the following formulation. Main agent ・ Bisphenol F type epoxy resin ("Epiclon # 830" manufactured by Dainippon Ink and Chemicals, Inc.) 72 parts ・ Titanium oxide ("Taipec R-820" manufactured by Ishihara Sangyo Co., Ltd.) 20 parts ・ For thixotropic agent Pre-gel 8 parts Curing agent-Oilized shell- "Epomate N-001" manufactured by Epoxy Co., Ltd.) 40 parts

The pregel is prepared by dissolving 5 parts of the thixotropic agent in 95 parts of the same type of bisphenol F type epoxy resin as described above by heating.

The results are shown in Table 1. There are 6 TI values
Ratio of rpm viscosity / 60 rpm viscosity.

Table 1 Main agent + thixotropic agent Type of thixotropic agent C-1 C-1 C-2 C-3 C-4 Addition form of thixotropic agent PG powder PG PG PG PG pregel addition amount (part) 8 8 8 8 Active ingredient (part) 0.4 0.4 ^# 0.4 0.4 0.4 Viscosity (cps / 25 ℃) 60rpm 9000 4800 7500 4860 5200 6rpm 22000 5000 14800 6000 6600 TI value 2.44 1.04 1.97 1.23 1.27 Main agent + thixotropic agent + curing agent Viscosity (cps / 25 ℃) 60rpm 7800 3620 3400 3780 3950 6rpm 13400 4000 3800 4300 4500 TI value 1.72 1.10 1.12 1.14 1.14 Wet film thickness (μm) 400 <75 <75 <75 <75 Appearance of coating film No abnormal No abnormal No abnormal No abnormal No abnormal No abnormal (Note) In the item of thixotropic agent addition form, PG is pregel. ^# Means powder addition.

As shown in Table 1, the addition of (C-1) and (C-2) markedly increases the viscosity of the base compound. However, when (C-1) is added, thixotropy can be obtained even if a curing agent is added. While there is
It can be seen that when (C-2) is added and the curing agent is added, the viscosity decreases and the thixotropy is lost. That is, (C-
2) With addition, the thixotropic effect disappears during application, while (C-1)
It can be seen that addition can increase the film thickness. Also, (C-
It can be seen that the addition of 3) and (C-4) does not give the expected thixotropy.

Further, even when di (methylbenzylidene) sorbitol (C-1) is used, almost no thixotropic effect is exhibited when added in powder form. Therefore, it can be seen that (C-1) needs to be pre-gelled and swelled and activated before being added to the paint.

Example 2 The following were prepared as thixotropic agents for non-aqueous paints. (C-1) Di (methylbenzylidene) sorbitol (C-5) Hydrogenated castor oil (C-6) Diamide (C-7) hexamethylenediamine which is a reaction product of ethylenediamine and 12-hydroxystearic acid Reaction of 12-hydroxystearic acid with diamide (C-8) Reaction of 12-hydroxystearic acid with diamide (C-9) Reaction of 12-hydroxystearic acid with diamide (C-9) methylpentamethylenediamine Diamide (C-10) Commercial fine particle silicic acid (C-11) Commercial organic bentonite

A coating composition was prepared with the following formulation. Main agent-Bisphenol A type liquid epoxy resin ("EPO MIK R-140" manufactured by Mitsui Petrochemical Co., Ltd.) 40 parts-Diluent-containing bisphenol A type epoxy resin ("EPIKOTE # 815" manufactured by Yuka Shell Epoxy Co., Ltd.) )) 21 parts Titanium oxide (“Taipec R-820” manufactured by Ishihara Sangyo Co., Ltd.) 20 parts • Pregel of thixotropic agent 20 parts Curing agent • (Epomate N-001 manufactured by Yuka Shell Epoxy Co., Ltd.) ) 40 copies

A pregel means that 5 parts of the above thixotropic agent is the same type of epoxy resin as that described above ("EPOMIK R-14").
0 ") dissolved in 95 parts by heating.

The results are shown in Table 2. There are 6 TI values
Ratio of rpm viscosity / 60 rpm viscosity.

Table 2 Main agent + thixotropic agent Thixotropic agent type C-1 Not used C-5 C-6 C-7 C-8 Thixotropic agent addition form PG-PG PG PG PG Pregel addition amount (part) 10- 10 10 10 10 Of which, active ingredient (part) 0.5 − 0.5 0.5 0.5 0.5 Viscosity (cps / 25 ° C) 60 rpm 9700 5200 7400 7200 7300 7400 6rpm 21000 8500 12200 12100 12400 12600 TI value 2.16 1.63 1.65 1.68 1.70 1.70 Main agent + thixotropic agent + Curing agent Viscosity (cps / 25 ℃) 60rpm 6600 3950 4420 4400 4510 4500 6rpm 10500 4600 5300 5300 5200 5400 TI value 1.59 1.16 1.20 1.20 1.15 1.20 Wet film thickness (μm) 350 <75 150 150 150 150 Appearance abnormality of coating film No Abnormal No Abnormal No Glossing Abnormal No Abnormal No

Table 2 (continued) Main agent + thixotropic agent Thixotropic agent type C-9 C-10 C-11 Thixotropic agent addition form PG powder Powder pregel addition amount (part) 10 Of these, active ingredient (part) 0.5 0.5 ^# 0.5 ^# viscosity (cps / 25 ℃) 60rpm 6800 6200 5220 6rpm 10900 10500 8500 TI value 1.60 1.69 1.63 base resin + thixotropic + curing agent viscosity (cps / 25 ℃) 60rpm 4360 4100 3970 6rpm 5100 4800 4700 TI value 1.17 1.17 1.18 Wet film thickness (μm) 125 100 <75 Appearance of coating film No abnormalities No abnormalities No abnormalities (Note) Gloss is bleeding and gloss is recognized. In the paragraph of the thixotropic agent addition form, PG is pregel. ^# Means powder addition.

When hydrogenated castor oil (C-5), diamide (C-6) to (C-9) or fine particle silicic acid (C-10) is added as a thixotropic agent, the thixotropic agent In some cases, the wet film thickness is thicker than in the case of not adding, but thixotropy is still insufficient at such a film thickness.

Although data is omitted, (C-6) to (C-9)
High-boiling hydrocarbons that are non-reactive diluting agents for diamide thixotropic agents (“Nisseki Hysol SAS manufactured by Nippon Oil Co., Ltd.
-296 ") made into a paste and epoxy resin (" Epiclon # 83 manufactured by Dainippon Ink and Chemicals Co.
0 ”) and a method of dispersing with a disper was adopted, the result was even worse than that in Table 2. From this, it is understood that the effect of the diamide cannot be sufficiently brought out even if it is attempted to swell with a medium of low polarity and hardly swelling.

Example 3 Base agent: 30 parts of bisphenol F type epoxy resin ("Epiclone # 830" manufactured by Dainippon Ink and Chemicals, Inc.) ・ Hexylene diglycidyl ether ("Denacol EX-" manufactured by Nagase Kasei Co., Ltd.) 212 ") 15 parts-Petroleum resin (" Nicanol LLL "manufactured by Mitsubishi Gas Chemical Co., Inc.) 20 parts-Bengala (Morishita Bengal Industry Co., Ltd.) 15 parts-Talc (" SC-25 manufactured by Fuji Talc Industry Co., Ltd. " )) 20 parts Defoamer ("AS-A DF-1" manufactured by Ito Oil Co., Ltd. diluted to 1/100 with methyl isobutyl ketone) 0.05 part ・ Pregel of thixotropic agent Hardener ・ Oil Shell Epoxy Co., Ltd. "Epomate LX-1S") 16 parts

The pregel is prepared by heating and dissolving 10 parts of the above thixotropic agent in 90 parts of the same type of epoxy resin (reactive diluent) as described above, and the pregel is blended with respect to the main agent. 3%, 5%, and 7%, and the compounding amount of "Denacol EX-212" was reduced by an amount commensurate with the compounding amount.

The results are shown in Table 3. There are 6 TI values
Ratio of rpm viscosity / 60 rpm viscosity.

Table 3 Main agent + thixotropic agent No type of thixotropic agent C-1 C-1 C-1 Thixotropic agent addition form PG PG PG Pregel addition amount (%) 0 3 5 10 Viscosity (cps / 25 ° C) 60rpm 1020 4200 6850 8900 6rpm 1500 12300 22900 31500 TI value 1.47 2.93 3.34 3.54 Base agent + thixotropic agent + curing agent Viscosity (cps / 25 ℃) 60rpm 890 2400 3650 5400 6rpm 1170 6000 11800 18700 TI value 1.31 2.50 3.23 3.46 Wet film Thickness (μm) 75 250 400 700

[0045]

The solvent-free or low-solvent type epoxy resin coating composition of the present invention has an excellent thixotropic effect because di (methylbenzylidene) sorbitol is added as a thixotropic agent. Prevents sagging and thickens the film.

Claims (2)

[Claims] 1. A solventless or low solvent type epoxy resin coating (E
P), as a thixotropic agent, di (methylbenzylidene) sorbitol (MD), which is a reaction product of methylated benzaldecht and sorbitol in a molar ratio of 2: 1, is epoxy resin paint.
Pregel (PG) pre-dissolved in liquid component (C) in (EP)
An epoxy resin coating composition containing: 2. The content of di (methylbenzylidene) sorbitol (MD) in the epoxy resin coating (EP) is 0.1 to 5% by weight.
The solventless epoxy resin coating composition according to claim 1.