JP2003253090A - Resin dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin dispersion using a crystalline polyester resin excellent in production stability, storage stability and roll-coating property. <P>SOLUTION: This resin dispersion is characterized by comprising the crystalline polyester resin (A) dispersed in an epoxy resin solution in which the epoxy resin (B) is dissolved in an organic solvent (C). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a resin dispersion in which a crystalline polyester resin is dispersed in an epoxy resin solution, and to a resin composition for can coating using the resin dispersion. .

[0002]

2. Description of the Related Art Conventionally, a resin containing a bisphenol A type epoxy resin has been widely used as a resin for coating the inner surface of a can. However, in recent years, for the purpose of improving productivity, a method in which a metal flat plate is first coated and the obtained coated steel sheet is processed into a can-like shape is often used, and the coating film requires hardness and workability at the same time. It has started to be done.

From the viewpoint of workability, vinyl organosol-based paints are excellent, but it has been pointed out that dioxin may be generated when incinerated.

Epoxy resins generally have hardness but are inferior in workability, and polyester resins have been investigated as an alternative to epoxy resins. However, hardness, adhesion, and corrosion resistance required for coatings for the inner surface of cans have been investigated. It is not easy to satisfy the strict coating film performance such as property and flavor retention.
It has become important to master a highly crystalline polyester resin represented by ET resin.

As a method of utilizing a crystalline polyester resin, use of a polyester film has been studied. For example, a biaxially stretched thermoplastic film is directly laminated on a metal plate or directly via an adhesive. (For example, JP-A-56-10451, JP-A-57-65463, etc.) or a method in which a thermoplastic resin is processed into a film and then laminated on a metal plate. A method of melting and directly extruding and laminating on a metal plate (for example, Japanese Patent Application Laid-Open No. 51-17988) is disclosed and partly put to practical use.

However, in order to use the film, new capital investment is required, and the workability is inferior. Therefore, there is a strong demand for a coating material using such a crystalline polyester resin.

[0007] Crystalline polyester resins generally have low solubility in solvents and have problems such as crystals precipitating during storage. Therefore, there are many problems in applying crystalline polyester resins as they are to coating materials. was there. In order to solve such a problem, a method of containing a crystalline polyester resin in a dispersed state in an amorphous polyester resin solution is disclosed in JP-A-4-164957 and 2001-2341.
For example, it is disclosed in Japanese Patent No. 15 publication. However, the amorphous polyester resin used in the method has a lower content such as hardness and perfume sorption properties when the content is high, and the storage stability of the resulting resin dispersion is low when the content is low. There is a problem of decrease.

The object of the present invention is that the storage stability of the resin dispersion is good, and the hardness of the film obtained from the resin composition for can coating using the resin dispersion, the fragrance sorption, etc. are problematic. Is to provide a resin dispersion that is not.

[0009]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that the above problems can be solved by using a resin dispersion liquid in which a crystalline polyester resin is dispersed in an epoxy resin solution. They have found that they can be solved and have completed the present invention.

Thus, the present invention is characterized in that the crystalline polyester resin (A) is dispersed in an epoxy resin solution prepared by dissolving the epoxy resin (B) in the organic solvent (C). Is provided.

The present invention also provides a method for producing the above resin dispersion.

Furthermore, the present invention provides a resin composition for coating the inner surface of a can, which uses the above resin dispersion.

The present invention will be described in more detail below.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The resin dispersion of the present invention comprises a crystalline polyester resin (A), an epoxy resin (B) and, if necessary, a phosphoric acid compound (D) added to an organic solvent (C). The crystalline polyester resin (A) which is crystallized and precipitated by heating, mixing and cooling is added to the epoxy resin (B) and the phosphoric acid compound (D) as required.
With the help of, it is dispersed as stable fine particles in an organic solvent.

Crystalline polyester resin (A) The crystalline polyester resin which is the component (A) of the resin dispersion is composed of an esterified product of a polybasic acid component and a polyhydric alcohol component.

Examples of the polybasic acid component include phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride, 2,6
-One or more dibasic acids selected from naphthalenedicarboxylic acid, 1,6-hexanedicarboxylic acid, etc. and lower alkyl esterified products of these acids are mainly used, and if necessary, benzoic acid, crotonic acid, pt -A monobasic acid such as butylbenzoic acid, a tribasic or higher polybasic acid such as trimellitic anhydride, methylcyclohexene tricarboxylic acid, and pyromellitic dianhydride are used in combination.

Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methylpentanediol, 1,4-hexanediol, 1,6-hexanediol, A dihydric alcohol such as butylethylpropanediol is mainly used, and if necessary, a polyhydric alcohol having a valence of 3 or more such as glycerin, trimethylolethane, trimethylolpropane and pentaerythritol can be used in combination. These polyhydric alcohols can be used alone or in admixture of two or more. The esterification or transesterification reaction of both components can be carried out by a method known per se.

Of the above-mentioned raw materials, the crystalline polyester resin mainly uses terephthalic acid and 2,6-naphthalenedicarboxylic acid as acid components, and mainly ethylene glycol and 1,4-butanediol as polyhydric alcohol components. Although it can be obtained by using, a polyethylene terephthalate resin mainly containing terephthalic acid and ethylene glycol is particularly preferable.

The crystalline polyester resin used in the present invention has a melting point of 190 ° C. to 260 ° C., preferably 200 ° C.
235 ℃, Intrinsic Viscosity 0.5
A range of 5 to 1.20, preferably 0.60 to 1.00 is suitable. The intrinsic viscosity of the polyester resin is a measure of the molecular weight, and if the intrinsic viscosity is low, the processability tends to be poor.If the melting point of the crystalline polyester resin is low, the sorption and barrier properties of the film are lowered, and the melting point is If it is too high, the film-forming property deteriorates.

The melting point of the crystalline polyester resin was measured by using an inspection scanning calorimeter (Shimadzu Corporation).

Commercially available crystalline polyester resins include, for example, IFG8L, TG7N10 (above manufactured by Kanebo Synthetic Fibers Co., Ltd.) and KF-511 (manufactured by Mitsubishi Rayon Co., Ltd.).

As the epoxy resin which is the component (B) of the epoxy resin (B) resin dispersion,
Examples thereof include bisphenol type epoxy resins, novolac type epoxy resins, and modified epoxy resins obtained by reacting various modifying agents with the epoxy groups or hydroxyl groups in these epoxy resins.

As the bisphenol type epoxy resin, for example, a resin obtained by condensing epichlorohydrin and bisphenol to a high molecular weight in the presence of a catalyst such as an alkali catalyst, if necessary, epichlorohydrin and bisphenol can be used, if necessary. It may be any resin obtained by condensation in the presence of a catalyst such as an alkali catalyst to give a low molecular weight epoxy resin, and subjecting this low molecular weight epoxy resin to a polyaddition reaction with bisphenol.

Examples of the bisphenol include bis (4-hydroxyphenyl) methane [bisphenol F], 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [bisphenol. A], 2,2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-)
Hydroxy-tert-butyl-phenyl) -2,2-
Examples include propane, p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4′-dihydroxybenzophenone, bis (2-hydroxynaphthyl) methane and the like. it can. The above bisphenols can be used alone or as a mixture of two or more.

Commercially available bisphenol type epoxy resins include, for example, Epicoat 1001, 1004, 1007, 1009, 1010 (all manufactured by Japan Epoxy Resins Co., Ltd.), AER6097, 60.
99 (all of which are manufactured by Asahi Kasei Epoxy Co., Ltd.) and Epomic R-309 (manufactured by Mitsui Chemicals, Inc.).

As the above novolac type epoxy resin,
Examples thereof include a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, and a phenol glyoxal type epoxy resin having a large number of epoxy groups in the molecule. Examples of commercially available novolac type epoxy resins include, as phenol novolac type, Epicoat 152, 154 (all of which are manufactured by Japan Epoxy Resins Co., Ltd.), EPPN-201 (manufactured by Nippon Kayaku Co., Ltd.), and Epotote YDPN-638 ( Toto Kasei Co., Ltd., etc., and as a cresol novolac type,
Epicoat 180S65, 180H65 (all from Japan Epoxy Resins Co., Ltd.), EOCN-102
S, the same -103S, the same -104S (these are all manufactured by Nippon Kayaku Co., Ltd.), Epotote YDCN-701, the same -70.
2, Same-703, Same-704 (all above are manufactured by Tohto Kasei Co., Ltd.), ECN1273, ECN1280, ECN12
99 (manufactured by Asahi Kasei Epoxy Co., Ltd.), and other novolac type epoxy resins such as Epotote ZX-1.
071T, ZX-1015, ZX-1247, Y
Examples include DG-414S (all of which are manufactured by Tohto Kasei Co., Ltd.).

As the modified epoxy resin, the bisphenol type epoxy resin or the novolak type epoxy resin is reacted with a drying oil fatty acid, for example, an epoxy ester resin, or a polymerizable unsaturated resin containing acrylic acid or methacrylic acid. Epoxy acrylate resin reacted with a monomer component, urethane modified epoxy resin reacted with an isocyanate compound, the above bisphenol type epoxy resin, novolac type epoxy resin or the above modified epoxy resin in various modified epoxy resins is reacted with an amine compound to give an amino group. Examples thereof include amine-modified epoxy resin obtained by introducing a group or a quaternary ammonium salt.

Among the above epoxy resins, the bisphenol type epoxy resin and the cresol novolac type epoxy resin are preferable from the viewpoint of the adhesion and workability of the coating film.

The compounding ratio of the crystalline polyester resin (A) and the epoxy resin (B) is (A) / (B) = weight ratio.
The range of 65/35 to 5/95, especially 45/55 to 10/90 is preferable from the viewpoint of the retort resistance and the corrosion resistance of the film obtained from the resin dispersion liquid.

Organic solvent (C) Organic solvent (C) used in the production of the resin dispersion of the present invention
Can be used as long as it can dissolve the above epoxy resin, but 50% by weight or more of the organic solvent (C) is a hydroxyl group-free organic solvent having a boiling point of 150 ° C to 220 ° C. Preferred from the viewpoint of production stability of the dispersion liquid, for example, N-methyl-2-pyrrolidone, isophorone, a ketone solvent such as cyclohexanone, DBE (manufactured by DuPont, dimethyl adipate, dimethyl glutarate, dimethyl succinate mixed solvent). And other ester solvents.

Phosphoric Acid Compound (D) The phosphoric acid compound (D), which is optionally used in the resin dispersion of the present invention, has a structure represented by the following formula (1) and has a surface active property during resin dispersion. It is considered that it acts as an agent and not only makes the dispersed particle diameter finer, but also prevents the particles of the obtained resin dispersion liquid from coalescing and stabilizes the dispersion system.

[0032]

[Chemical 2]

R ₁ , R ₂ and R ₃ are the same or different and each represents an aliphatic hydrocarbon having 6 or more carbon atoms, preferably 8 or more carbon atoms or an aromatic hydrocarbon having 6 or more carbon atoms, and m
And n are integers of 1 or more and m + n is an integer of 6 or more.

Examples of the phosphoric acid compound (D) include 2-ethylhexyldiphenyl phosphate, tris (2-ethylhexyl) phosphate, tris (butoxyethyl) phosphate, triphenylphosphate,
Examples thereof include tricresyl phosphate.

The compounding amount of the phosphoric acid compound (D) is as follows.
Storage of the resin dispersion liquid in which 0.1 to 20 parts by weight, preferably 1 to 15 parts by weight, is obtained based on 100 parts by weight of the total solid content of the crystalline polyester resin (A) and the epoxy resin (B). Suitable from a stability point of view.

Method for producing resin dispersion A crystalline polyester resin (A), an epoxy resin (B) and, if necessary, a phosphoric acid compound (D) are heated and dissolved in an organic solvent, and then the resulting solution is prepared. When cooled, the crystalline polyester resin (A) crystallizes and precipitates to obtain a resin dispersion.

Cooling in the case of production in a tank or the like is generally slow at about 0.1 to 1 ° C. per minute, but when a polyester resin having a high melting point and high crystallinity is used, the cooling rate is slow. As the diameter of the precipitated resin particles increases, the stability of the dispersion decreases. The effect mainly appears as a decrease in storage stability of the resin dispersion or a coating composition using the dispersion, but even if the storage stability does not decrease so much, it is dispersed when a strong share like roll coating is applied. There is also a phenomenon that particles are fused together and the viscosity becomes so high that they cannot be coated by a normal roll coating machine, resulting in a problem that coating cannot be performed well. The stability of the resin dispersion liquid is greatly influenced by the cooling rate from the temperature rising crystallization start temperature of the crystalline polyester resin (A) to the glass transition temperature of the crystalline polyester resin (A). The cooling rate from the temperature above the temperature rising crystal starting temperature of A) to the temperature below the glass transition temperature of the crystalline polyester resin (A) is 2 ° C./minute or more, preferably 3 to 10
By carrying out at a temperature of C / min, a resin dispersion having good storage stability and roll coatability can be obtained.

As a manufacturing device, a device for heating and melting the resin and a device for rapidly cooling the solution may be used.

The resin dispersion is prepared by first heating the crystalline polyester resin (A) and the epoxy resin (B) in a solvent at a high temperature, preferably at or above the temperature rise of the crystalline polyester resin (A). Make a resin solution at a temperature of.

There are no particular restrictions on the procedure for producing the high temperature resin solution. For example, the organic solvent (C) and the crystalline polyester resin (A) in the form of pellets are mixed, heated with stirring and dissolved, and then the epoxy resin (B) is added. ) Is added. Method of heating and dissolving after mixing the organic solvent (C), the epoxy resin (B) and the crystalline polyester resin (A), in a solution of the heated epoxy resin (B) in the organic solvent (D) To the crystalline polyester resin (A) is gradually added. Dissolution of the crystalline polyester resin (A)
It is not always necessary to raise the temperature to the melting point of the resin in the organic solvent, and if the temperature is higher than the temperature at which the resin starts to crystallize, it should be as low as possible within the range where there is no problem in workability to avoid decomposition of the polyester resin by heat. It is suitable for

After the crystalline polyester resin (A) and the epoxy resin (B) are dissolved, they are cooled according to the cooling conditions of the present invention as soon as possible. When all heating, melting, and cooling are performed in the same device (for example, tank), it is necessary to use a device with excellent cooling performance or to select a place that meets the above cooling conditions by reducing the charging amount. is there. Further, it is possible to employ a method of heating in the cooling step and quenching separately from the dissolving device, for example, a method of heating and carrying in the dissolved resin solution into a pre-cooled tank or a pipe with a cooling device. it can.

Further, a part of the organic solvent (C) may be used as an auxiliary means for cooling by cooling it and adding it at the time of cooling.

After cooling to a temperature not higher than the glass transition temperature of the crystalline polyester resin (A), the cooling rate thereafter is not particularly limited.

Further, although the phosphoric acid compound (D) has an effect on the storage stability even if it is added after cooling, the effect on the stability of the resin dispersion is greater when it is added during or before cooling. It is particularly preferable to add it before cooling.

The resin dispersion obtained as described above may be used alone or in combination with other organic resins, crosslinking agents, additives (curing catalyst, lubricity imparting agent, defoaming agent, leveling agent, anti-aggregation agent, etc.). , Pigments (organic pigments, inorganic pigments, bright pigments, extender pigments, rust-preventive pigments, etc.), organic solvents, etc.
Although a coating composition having excellent adhesion and corrosion resistance can be obtained, it exhibits particularly excellent properties as a coating for the inner surface of a can.

Resin composition for coating the inner surface of a can When the resin composition for coating the inner surface of a can is prepared using the resin dispersion of the present invention, the resin dispersion may be used alone, or a cross-linking agent such as a resol type phenol resin may be used. Retort resistance, adhesion, flavor and the like are further improved by combining with agents.

As the above-mentioned resol type phenol resin,
A phenol component and formaldehydes are heated in the presence of a reaction catalyst to cause a condensation reaction to introduce a methylol group, and a part of the methylol group of a methylolated phenol resin obtained by alkyletherification with an alcohol.

In the production of the resol type phenol resin cross-linking agent, the above phenol component as a starting material is
A bifunctional phenol compound, a trifunctional phenol compound, a tetrafunctional or higher functional phenol compound, etc. can be used.

Examples of the bifunctional phenol compound used for producing the resol type phenol resin crosslinking agent include o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol,
Examples thereof include difunctional phenols such as 2,5-xylenol, and examples of trifunctional phenol compounds include phenol, m-cresol, m-ethylphenol, 3,5-xylenol, and m-methoxyphenol. Examples of the tetrafunctional phenol compound include bisphenol A and bisphenol F. These phenol compounds may be used alone or in combination of two or more.

The formaldehydes used for producing the resol type phenol resin include formaldehyde,
Paraformaldehyde, trioxane, etc. are mentioned, and they can be used individually or in mixture of 2 or more types.

The alcohol used for alkyl-etherifying a part of the methylol group of the methylolated phenolic resin has 1 to 8 carbon atoms, preferably 1 to 8 carbon atoms.
Four monohydric alcohols can be preferably used.
Suitable monohydric alcohols include methanol, ethanol, n-propanol, n-butanol, isobutanol and the like.

The amount of the resol-type phenolic resin is 1 to 30 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the total solid content of the crystalline polyester resin (A) and the epoxy resin (B). The range is suitable from the viewpoint of the balance between curability and processability.

An acid catalyst can be added to the above coating composition, if necessary, in order to accelerate the curing reaction. Specific examples include acid catalysts such as paratoluene sulfonic acid, dodecylbenzene sulfonic acid, dinonylnaphthalene sulfonic acid, dinonyl naphthalene disulfonic acid, phosphoric acid, and amine neutralized products of these acids.
Among them, the sulfonic acid compound or an amine neutralized product of the sulfonic acid compound is preferable.

From the viewpoint of physical properties of the coating film obtained, the amount of the acid catalyst to be blended is the amount of acid (for example, in the case of an amine neutralized product of a sulfonic acid compound, the remaining sulfone obtained by removing the amine from this neutralized product). 0.1 to 5 parts by weight, preferably 0.5 to 2 parts by weight based on 100 parts by weight of the total solid content of the crystalline polyester resin (A) and the epoxy resin (B) as the acid compound amount).
A range of parts by weight is suitable.

The coating composition may further contain, if necessary, an amorphous polyester resin, an additive (lubricity imparting agent, defoaming agent, leveling agent, anti-aggregation agent, etc.), pigment (organic pigment, inorganic pigment). Pigments, bright pigments, extender pigments, rust preventive pigments, etc.) and organic solvents can be combined with commonly known raw materials.

The coating composition can be coated on a flat metal plate by a known coating method such as a roll coater or a curtain flow coater, and baked to form a coating film suitable for the inner surface of a can. As a coating amount, a dry coating amount is 40 to 180 mg / 100 cm ² ,
It is preferably in the range of 60 to 150 mg / 100 cm ² . The baking condition of the coating film is usually about 15 seconds to about 30 minutes under the condition that the maximum temperature of the metal plate is about 190 to 300 ° C.

Examples of the material of the can include untreated steel sheet, tin-plated steel sheet, zinc-plated steel sheet, chrome-plated steel sheet, phosphate-treated steel sheet, chromate-treated steel sheet, non-treated aluminum sheet, chromate-treated aluminum sheet. Metal materials such as

[0058]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In the following, "part" and "%"
All are based on weight.

Production of Resin Dispersion Example 1 Crystalline polyester resin KF511 (Crystalline polyester resin manufactured by Mitsubishi Rayon Co., Tg 60 ° C., Tm [melting point]
214 ° C, intrinsic viscosity 0.78 dl / g) 9 parts and DBE
(DuPont dimethyl adipate, dimethyl glutarate, dimethyl succinate mixed solvent) 12 parts, N-
12 parts of methyl-2pyrrolidone was charged into a nitrogen gas-substituted four-necked flask equipped with a cooling tube, heated to about 200 ° C. with a mantle heater while stirring with a stirring blade, and KF5
11 was completely dissolved. Next, the heating was stopped and 6 parts of cyclohexanone and Solvesso 100 (manufactured by ExxonMobil,
15 parts of aromatic hydrocarbon solvent) and butyl derosolve 1
After 5 parts were dropped, Epicoat 1010 (manufactured by Japan Epoxy Resins Co., bisphenol A type epoxy resin, number average molecular weight of about 5,500, epoxy equivalent of about 4,000)
21 parts were charged and stirred until completely dissolved and cooled to 160 ° C. To this solution, 5 parts of 2-ethylhexyldiphenyl phosphate was charged, cooled from a cooling start temperature of 160 ° C. to a cooling end temperature of 55 ° C. at a rate of 5 ° C./min, 5 parts of methyl isobutyl ketone and 5 parts of methyl ethyl ketone were charged, and a solid content was about A resin dispersion a1 having a particle size of 33% and a particle size of about 5 μm was obtained. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Example 2 9 parts of crystalline polyester resin KF511 and 24 parts of N-methyl-2pyrrolidone were placed in a four-neck flask in which a nitrogen gas was replaced with a cooling tube, and a mantle heater was used for stirring while stirring with a stirring blade. KF511 heated to 200 ℃
Was completely dissolved. Next, the heating was stopped, 6 parts of cyclohexanone, 15 parts of Solvesso 100, 1 part of butyl derosolve
After 5 parts were dropped, Epicoat 1009 (manufactured by Japan Epoxy Resins Co., bisphenol A type epoxy resin, number average molecular weight of about 3,800, epoxy equivalent of about 2,600)
21 parts were charged and stirred until completely dissolved and cooled to 160 ° C. To this solution, 5 parts of 2-ethylhexyldiphenyl phosphate was charged, cooled from a cooling start temperature of 160 ° C. to a cooling end temperature of 55 ° C. at a rate of 5 ° C./min, 5 parts of methyl isobutyl ketone and 5 parts of methyl ethyl ketone were charged, and a solid content was about A resin dispersion a2 having 33% and a particle diameter of about 5 μm was obtained. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Example 3 The crystalline polyester resin KF511 in Example 2 was used.
In place of 9 parts, Epocoat 1009 in place of 21 parts, Epicoat 1007 (manufactured by Japan Epoxy Resins Co., bisphenol A type epoxy resin, number average molecular weight about 2,900, epoxy equivalent about 2,000) 18 parts Solid content of about 33% as in Example 2 except for use.
%, A resin dispersion a3 having a particle diameter of about 5 μm was obtained. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Example 4 In Example 2, instead of Epicoat 1009, Epicoat 4010P (manufactured by Japan Epoxy Resins, bisphenol F type epoxy resin, number average molecular weight of about 5,50) was used.
A resin dispersion a4 having a solid content of about 33% and a particle size of about 5 μm was obtained in the same manner as in Example 2 except that 0, epoxy equivalent of about 4,400) was used. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Example 5 The crystalline polyester resin KF511 in Example 2 was used.
18 parts instead of 12 parts, and ECN1299 (orthocresol novolac type epoxy resin manufactured by Asahi Kasei Epoxy Co., number average molecular weight about 1,200, epoxy equivalent about 220) instead of 12 parts of Epicoat 1009 except for 12 parts In the same manner as in Example 2, a resin dispersion liquid a5 having a solid content of about 33% and a particle size of about 5 μm was obtained. Resin dispersion is 2
Even when stored at 0 ° C. for 1 month, no precipitation or thickening was observed and it was stable.

Example 6 In the same manner as in Example 2 except that 15 parts of Epicoat 1009 and 6 parts of ECN1299 were used in place of 21 parts of Epicoat 1009 in Example 2, solid content of about 33%, A resin dispersion liquid a6 having a particle diameter of about 5 μm was obtained. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Example 7 In Example 2, instead of KF511, IFG8L (Kanebo Gosei Co., Ltd. crystalline polyester, Tg 72 ° C., Tm) was used.
A resin dispersion liquid a7 having a solid content of about 33% and a particle size of about 5 μm was obtained in the same manner as in Example 2 except that [melting point] 226 ° C. and intrinsic viscosity 0.80 dl / g) were used. Resin dispersion is 2
Even when stored at 0 ° C. for 1 month, no precipitation or thickening was observed and it was stable.

Example 8 TG7N10 was used in place of KF511 in Example 2.
(Kanebo synthetic fiber crystalline polyester, Tg 79 ℃,
Tm [melting point] 230 ° C., intrinsic viscosity 0.75 dl / g) was used in the same manner as in Example 2 except that the solid content was about 33%,
A resin dispersion a8 having a particle diameter of about 5 μm was obtained. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Example 9 The solid content was the same as in Example 2 except that TOP (Tris (2-ethylhexyl) phosphate, manufactured by Daihachi Chemical Industry Co., Ltd.) was used in place of 2-ethylhexyldiphenylphosphate in Example 2. About 33%, particle size about 5
A resin dispersion a9 having a thickness of μm was obtained. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Comparative Example 1 In Example 2, 21 parts of KF511 was used instead of 9 parts,
A resin dispersion a10 having a solid content of about 33% and a particle size of about 20 μm was obtained in the same manner as in Example 2 except that 9 parts of Epicoat 1009 was used instead of 21 parts. When the resin dispersion was stored at 20 ° C. for 1 month, precipitation was observed.

Comparative Example 2 Example 2 was repeated except that GM925 (Crystalline polyester manufactured by Toyobo Co., Ltd., Tg 15 ° C., Tm [melting point] 166 ° C., intrinsic viscosity 0.75 dl / g) was used in place of KF511 in Example 2. In the same manner as above, a resin dispersion liquid a11 having a solid content of about 33% and a particle size of about 5 μm was obtained. Resin dispersion is 2
Even when stored at 0 ° C. for 1 month, no precipitation or thickening was observed and it was stable.

Comparative Example 3 Instead of KF511 in Example 2, MA585 (a crystalline polyester manufactured by Mitsubishi Rayon Co., Tg 69 ° C., Tm) was used.
A resin dispersion a12 having a solid content of about 33% and a particle diameter of about 5 μm was obtained in the same manner as in Example 2 except that the melting point was 255 ° C. and the intrinsic viscosity was 0.49 dl / g. The resin dispersion was stable even when stored at 20 ° C. for one month without precipitation or thickening.

Production and Evaluation of Resin Composition for Coating Inner Surface of Cans Examples 10 to 20, Comparative Examples 4 to 10 Each material was blended in a container having a stirrer according to the formulation table shown in Table 1 below, and the resin for coating inner surface of each can was prepared. A composition was made.

The roll coating suitability (paintability) of each of the above resin compositions for coating the inner surface of a can was evaluated according to the following test method. In addition, the resin composition for coating the inner surface of each can is 505
2 Aluminum plate has a dry coating film weight of 120 per 100 cm ^2.
Bar coater coating to make mg, 270 in 20 seconds
Each coated plate was prepared by baking and drying under conditions of reaching ℃.

With respect to each coated plate obtained by the above-mentioned method for producing a coated plate, the coated surface state, adhesion, workability, perfume sorption, retort resistance, and corrosion resistance were evaluated according to the following test methods. The test results are shown in Table 1 below.

Test Method Suitability for Roll Coat: The dispersion composition was tested for No. 1 using a reverse roll coater with the following conditions as standard. It was coated on a 5052 aluminum plate and evaluated according to the following criteria. -Coating conditions: As a peripheral speed ratio of each roll, a backup roll / coating roll / pickup roll = 1.
0 / 1.05 / 0.4 ・ Film thickness: Dry coating weight is about 120 m per 100 cm ^2.
g ・ Baking: No. 5052 aluminum plate, 27 seconds in 20 seconds
Conditions reaching 0 ° C .: A uniform film thickness of about 120 mg per 100 cm ² can be applied. Δ: The film thickness is non-uniform. X: With a roll coater, an unpainted portion occurs and the entire surface cannot be coated.

Coating state: The coating surface of the coated plate was visually observed and evaluated according to the following criteria. ○: The entire coated surface is smooth. Δ: Slight unevenness is observed on the entire coated surface. X: Large unevenness is observed on the entire coated surface.

Blocking property: Each coated metal plate is 5 cm ×
Cut to a size of 5 cm and apply the specified paper (Kleenex Facial Tissues by Crecia) to the coated surface.
24 at 30 Kg / cm ² in a 60 ° C. atmosphere.
After pressurizing for a period of time, it was taken out, returned to room temperature, the paper was peeled off, and the state was evaluated. ○: Peelable △: Peelable, but paper fibers remained in the coating film ×: Cannot be peeled off

Adhesiveness: A knife was used to make 11 cuts in each of the vertical and horizontal widths on the coating film of the paint board in the width of about 1.5 mm, and a 24 mm wide cellophane adhesive tape was adhered to the film for strong peeling. The coating film on the eye area at the time of observing was observed and evaluated according to the following criteria. ◯: No peeling is observed. Δ: Peeling is recognized. X: Remarkable peeling is recognized.

Workability: A 180-degree bent portion is provided on the lower part of the coated plate with the coating surface outside, and a special goby folding type DuPont impact tester is used to make a flat contact surface on the bent portion. The length of cracks in the coating film at the bent portion, which occurred when a 1 kg iron weight was dropped from a height of 50 cm, was measured and evaluated according to the following criteria. ◯: less than 5 mm. Δ: 5 mm or more and less than 10 mm. X: 10 mm or more.

Retort whitening: The coated plate was immersed in deionized water at 125 ° C. for 35 minutes in an autoclave and pulled up, and then the whitening state of the coating film was observed and evaluated according to the following criteria. ◯: Slight whitening is observed in the coating film Δ: Significant whitening is observed in the coating film ×: Significant whitening is observed in the coating film

Corrosion resistance: The coated surface is the inner surface, and like a lid with a mouth of a can, it is processed into a basic end with a diameter of 2 inches with a dedicated press machine, and further rivet hole processing and score processing. A can lid was prepared. The lid was wrapped around a 2-piece can having an inner surface coated with 10% pine juice and stored at 35 ° C. for 1 month, after which the corrosion state of the test coated surface was observed and evaluated according to the following criteria. . ○: No corrosion is observed. Δ: Corrosion is considerably observed. X: Corrosion is remarkable.

Perfume sorptive property: The coated plate was dipped in a liquid prepared by dispersing 30 mg / L of d-limonene solution in an amount of 1 g / L of S-1170 (sucrose fatty acid ester manufactured by Mitsubishi Chemical Co., Ltd.) in deionized water at 35 ° C. Store for 1 month at. After storage, the d-limonene sorbed on the coating is extracted with diethyl ether at 20 ° C. for 1 week. It was measured by gas chromatography in which a calibration curve for d-limonene quantification was prepared in advance, and evaluated according to the following criteria. ◯: Less than 0.6 mg per 120 mg of coating film weight. B: 0.6 mg or more and 1.6 m per 120 mg of coating film weight
less than g. X: 1.6 mg or more per 120 mg of coating film weight.

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[Table 1]

[0083]

[Table 2]

The raw materials of each note (* 1) to (* 4) in Table 1 have the following contents. (* 1) Hitanol 3305N: Hitachi Chemical Co., Ltd., cresol / p-tert-butylphenol / formaldehyde type phenol resin solution, solid content about 42%. (* 2) Balcam 29-101: BTL SPECIA
Made by LTY RESINS, xylenol / formaldehyde type phenol resin, solid content 100%. (* 3) Cymel 303: Mitsui Cytec, methylated melamine resin, solid content 100%. (* 4) NACURE 5925: A product of King Industries, a neutralized solution of dodecylbenzenesulfonic acid in amine, 25% active ingredient.

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INDUSTRIAL APPLICABILITY The resin dispersion liquid of the present invention is one in which a crystalline polyester resin which is insoluble in a solvent can be uniformly dispersed in an organic solvent by an epoxy resin and optionally a specific phosphoric acid compound. Thus, the storage stability of the obtained resin dispersion is also extremely excellent. Further, the coating composition using the resin dispersion is also excellent in roll coating workability, and a coating obtained by coating a metal material has adhesiveness, processability, flavor sorption and resistance. Since it exhibits excellent properties such as retort properties and corrosion resistance, it is particularly suitable as a resin composition for coating the inner surface of a can.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 5/08 C09D 5/08 163/00 163/00 167/00 167/00 F term (reference) 4F070 AA46 AA47 AC55 AE07 CA11 CB11 4J002 CD00X CD04X CD06X CF00W CF04W EW046 GH00 GH01 4J038 DB061 DB062 DB071 DB072 DB451 DB452 DB471 DB472 DB481 DB482 DB491 DB492 DD061 DD062 DD072 JA32 JA53 JB27 JC15 PKA06 MA13

Claims (10)

[Claims] 1. An epoxy resin (B) in an organic solvent (C).
A resin dispersion liquid comprising a crystalline polyester resin (A) dispersed in an epoxy resin solution in which is dissolved. 2. The resin dispersion according to claim 1, wherein the melting point of the crystalline polyester resin (A) is in the range of 190 ° C. to 260 ° C. 3. The resin dispersion according to claim 1, wherein the crystalline polyester resin (A) has an intrinsic viscosity (Intrinsic Viscosity) of 0.55 to 1.20. 4. The weight ratio of the crystalline polyester resin (A) and the epoxy resin (B) is (A) / (B) = 65/3.
The resin dispersion liquid according to any one of claims 1 to 3, which is within a range of 5 to 5/95. 5. The crystalline polyester resin (A), wherein the resin dispersion further contains a phosphoric acid compound (D) represented by the following formula (1).
It is within the range of 0.1 to 20 parts by weight based on 100 parts by weight of the total solid content of the epoxy resin (B) and the epoxy resin (B).
The resin dispersion according to any one of 1. [Chemical 1] R ₁ , R ₂ and R ₃ are the same or different and each is an aliphatic or aromatic hydrocarbon having 6 or more carbon atoms, or -C _m H.
_2m OC _n H _{2n + 1} , m and n are integers of 1 or more, and m + n is an integer of 6 or more. 6. The resin dispersion according to claim 5, wherein the phosphoric acid compound (D) is 2-ethylhexyl diphenyl phosphate. 7. An organic solvent (C) comprising 50% by weight or more of
The resin dispersion liquid according to any one of claims 1 to 6, which is an organic solvent having a boiling point of 150 ° C to 220 ° C and containing no hydroxyl group. 8. A crystalline polyester resin (A), an epoxy resin (B), and optionally a phosphoric acid compound (D) are heated and dissolved in an organic solvent (C), and then the resin solution is cooled. A method for producing a resin dispersion, comprising: 9. In cooling the resin solution, a speed of 2 ° C. or more per minute from a temperature above the temperature rising crystallization start temperature of the crystalline polyester resin (A) to a temperature below the glass transition temperature of the crystalline polyester resin (A). 9. The method for producing a resin dispersion according to claim 8, wherein the method is rapidly cooled. 10. A resin composition for can coating, comprising the resin dispersion according to any one of claims 1 to 7.