JPH0292916A - Resin composition and coating compound composition for can - Google Patents

Abstract

PURPOSE:To obtain resin composition having excellent processing resistance, adhesivity to metal, solvent popping resistance, etc., containing a specific epoxy group-containing polyhydric phenol modified epoxidized polybutadiene resin and a resol type phenol resin as essential components. CONSTITUTION:The aimed composition containing (A) an epoxy group-containing polyhydric phenol modified epoxidized polybutadiene resin prepared by reacting an epoxidized polybutadiene resin (preferably one having 3-12wt.% oxirane oxygen content and 1,000-10,000 number-average molecular weight) with a polyhydric alcohol (e.g., catechol) and (B) a resol type phenol resin as essential components. The composition is used as a vehicle component to give a coating compound composition for cans.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a novel resin composition and a coating composition for cans.

(Prior art and its problems) Conventionally, the inner surface of metal cans such as food cans and beverage cans is coated with can paint to prevent metal elution and corrosion of the can.

Currently, metal cans are two-piece cans obtained by punching (deep drawing, etc.) a coated metal plate with a can coating film formed on the surface of the metal plate for cans, and the coated metal plate is used as a can body material. Three-piece cans and the like are widely used, which are obtained by cutting the can body material, overlapping both ends of the cut surfaces, welding, and then seaming the bottom lid.

The above-mentioned two-piece can requires a high degree of workability.

In addition, in a three-piece can, a repair paint (side seam paint) is usually required at the joint of the can body to prevent metal from leaching out. Since this repair paint is applied locally to areas with differences in level, it is required to have a thick film that does not cause wrinkles even if it is applied to a thickness of 30 to 50 μm and baked, and since it is baked in a short time, it is hard to cure. Excellent properties (drying properties) are required.

As the above-mentioned repair paint, vinyl chloride resin-based organosol compositions and thermosetting resins (epoxy resins, resol resins, amino resins)/polybutadiene (JP-A-61-26
8768) etc. are proposed.

However, it is difficult to set baking conditions for the former vinyl chloride resin-based organosol composition.

In other words, baking occurs when the temperature is below about 290°C, as curing is insufficient, making it impossible to obtain a paint film with excellent flavor, hardness, and safety. There is a problem in that it causes wrinkles and cannot exhibit its performance as a coating film for cans.

On the other hand, the latter thermosetting resin/polybutadiene composition is
This is a composition obtained by dissolving a three-component mixture of an epoxy resin, a resol resin (thermosetting resin), and a polybutadiene resin in an organic solvent. Since the compatibility between the polybutadiene resin and the resol resin in this composition is insufficient, the resin component may separate and precipitate in the organic solvent during storage, and the coating film formed from this composition may not be uniformly cured. This results in a coating film with poor processing resistance, retort resistance, adhesion to metals, etc. Furthermore, in the composition, if the amount of polybutadiene resin is reduced to such an extent that the resin component does not separate or precipitate during storage, the coating film will have poor scuffing resistance and processing resistance, making it difficult to satisfy the above performance.

The purpose of the present invention is to develop a resin composition that has excellent storage stability and forms a coating film that has excellent processing resistance, scuffing resistance, and the like.

(Means for Solving the Problems) As a result of various studies on methods to overcome these drawbacks, the present inventors have developed a polyhydric phenol-modified epoxidized resin obtained by reacting an epoxidized polybutadiene resin with a polyhydric phenol. The present inventors have discovered that polybutadiene resin has excellent compatibility with resol type phenolic resin and forms a coating film that satisfies the above performance, and has completed the present invention.

That is, the present invention provides an epoxy group-containing polyphenol-modified epoxidized polybutadiene resin (
A) (this product may be simply abbreviated as "resin (A)") and a resol type phenolic resin (B) as essential components, and a resin composition characterized by containing the resin composition. A paint composition for cans, comprising a vehicle component.

As the epoxidized polybutadiene resin used in the resin composition of the present invention, conventionally known resins can be used, in which oxirane groups are introduced using functional groups such as double bonds, hydroxyl groups, and carboxyl groups in liquid polybutadiene resin. As an example of the above, for example, as a method for introducing an oxirane group using a double bond in a liquid polybutadiene resin, it can be obtained by modifying the liquid polybutadiene resin with a peracid such as peracetic acid or performic acid. can. Further, as a method for introducing oxirane groups using the hydroxyl groups in the liquid polybutadiene resin, it can be obtained, for example, by reacting the liquid polybutadiene resin with a low molecular weight epoxy compound such as shrimp herrohydrin.

As a specific example of the resin mentioned above, for example, R-45EPI
%R-15EPI, E-1000-8, E-1800-
6,5, E-1000-3,5, BP-1000, E-
700-6,5 (trade name, manufactured by Idemitsu Petrochemical Co., Ltd.) and the like.

In addition, as a method for introducing an oxirane group using a carboxyl group in a liquid polybutadiene resin, for example, a compound or resin having an average of two or more oxirane groups in one molecule (such as diglycidyl ether, glycidyl phenyl glycidyl ether, 2
．． 6-sibricidylphenylglycidyl ether, glycerin tetraglycidyl ether, epichlorohydrin bisphenol, etc.).

Among the above-mentioned resins, it is preferable to use one in which an oxirane group is introduced using a double bond or a hydroxyl group in the liquid polybutadiene resin since there is no risk of an increase in molecular weight.

As the liquid polybutadiene resin, a polybutadiene resin containing 20% by weight or more of 1,2-butadiene units can be used.

In addition, epoxidized polybutadiene resin has an average of 3 to 3 oxirane oxygen (oxygen atoms in the oxirane group) per molecule.
Contains 12% by weight, preferably 3 to 9% by weight on average, and has a number average molecular weight of 1000 to 10000, preferably 100.
0 to 3500. Oxirane oxygen content is 3
If the amount is less than % by weight, the resin obtained by reacting the epoxidized polybutadiene resin with a polyhydric phenol compound (
Since the polyhydric phenol component chemically bonded to A) is reduced, the compatibility with the resol type phenolic resin (B) is poor, resulting in a coating with poor storage stability, processing resistance, retort resistance, and adhesion to metals. On the other hand, oxiranes with an oxygen content of more than 12% by weight are difficult to obtain. If the number average molecular weight is less than 1,000, the final coating film will be sticky, resulting in poor line workability and poor coating performance.On the other hand, if the number average molecular weight is greater than 10,000, The drawback is that the viscosity increases rapidly in the reaction system with the polyhydric phenol compound, making it difficult to manufacture.

The above-mentioned epoxidized polybutadiene resin is reacted with a polyhydric phenol compound to obtain an epoxy group-containing polyhydric phenol-modified epoxidized polybutadiene resin (A) used in the resin composition of the present invention.

As the polyhydric phenol compound, a compound containing an average of 2 or more phenolic hydroxyl groups, preferably 2 to 3 phenolic hydroxyl groups in one molecule can be used. Specifically, examples include monocyclic phenol compounds such as catechol, resorcinol, hydroquinone, pyrogallol, hydroxyhydroquinone, and phloroglucin; , R+ which may be substituted with an alkyl group, an alkoxy group, a nitro group, an amino group or a cyano group
is an alkylene group, -〇-1-CH,0-1-CHI O
CH, - or -SO□-, n is an integer of 1 to 10] Examples include polycyclic phenol compounds represented by the following.

In the above general formula, "halogen atom" is fluorine,
It is an atom such as chlorine or bromine, and as an "alkyl group", those of 01 to 8 are preferable, such as methyl, ethyl,
Examples include propyl, butyl, pentyl, octyl, and the like. The "alkoxy group" is preferably one having C1 to -, and includes, for example, methoxy, ethoxy, propoxy, butoxy, pentoxy, octyloxy, and the like.

The "alkylene group" is preferably C1-.

CH.

For example, -CHl--C-C-H-CH
Examples include s -C-.

Cxt'b Specific examples of the polycyclic phenol compounds represented by the above general formula include 2.2-bis(4-hydroxyphenyl)propane [bisphenol A], 2.2-bis(4-hydroxyphenyl) ) Butane [bisphenol B], l, 1-bis(4-hydroxyphenyl)ethane, bis(4-hydroxyphenyl)methane [bisphenol F], 4-hydroxyphenyl ether, p-(4
-Hydroxy) phenol, HO-c > 000 fertilizer HOOCH* OCH* <Σ0 former HO-f5 SO, Q OH.

etc.

The reaction between the epoxidized polybutadiene resin and the polyhydric phenol compound is usually carried out by reacting a mixture of the epoxidized polybutadiene resin and the polyhydric phenol compound in the presence of a catalyst to about 10%
It is carried out at a temperature of 00 to 200°C, preferably about 140 to 160°C.

For example, when a dihydric phenol compound is used, the reaction ratio between the epoxidized polybutadiene resin and the polyhydric phenol compound is approximately 0.01 to 0.45 mol per oxirane group in the epoxidized polybutadiene resin. Also 3
When using a phenolic compound, approximately 0.006
~0.3 mol can be used.

If the reaction ratio of the polyhydric phenol compound is less than the above range, the compatibility with the resol type phenolic resin (B) will be insufficient, resulting in the formation of a coating film with poor storage stability, processing resistance, retort resistance, and adhesion to metals. On the other hand, if the reaction ratio is greater than the above range, the content of oxirane oxygen in the resin (A) will decrease, resulting in the formation of a coating film with poor curability, which is not preferable.

Furthermore, the resin (A) contains oxirane oxygen in an average of about 1 to 11.5% by weight, preferably an average of about 2 to 10% by weight in one molecule.
and has a number average molecular weight of 1,100 to 20,000. Preferably, it can have about 1100-5000.

As the catalyst, conventionally known ring-opening catalysts for oxirane groups, such as ammonia, dimethylamine, jetanolamine, and other ammonia and amine compounds, nitriethylammonium bromide, trimethylammonium chloride, and other quaternary salts can be used. .

The resol type phenolic resin (B) used in the resin composition of the present invention is, for example, one obtained by mixing one or more of phenol, cresols, alkylphenols, and bisphenols with formaldehyde under a basic catalyst. Alternatively, conventionally known resins such as phenol resins obtained by etherifying these with alcohols such as ethanol and butanol can be used.

The resin composition of the present invention can be obtained by mixing the resin (A) and the resol type phenolic resin (B). The mixing ratio of both resin components is resin (A) 95
-50% by weight, preferably 85-70% by weight, and 5-50% by weight of resin (B), preferably 15-30% by weight. The resin (A) is more than 95% by weight, or the resin (A) is more than 95% by weight.
When B) is less than 5% by weight, the curing properties are insufficient and a coating film is formed that is poor in retort resistance, processing resistance, adhesion to metals, and coating hardness; on the other hand, when the resin (A) is 70% by weight less or when the resin (B) is more than 30% by weight,
This is not preferable because the coating film becomes brittle, has poor processing resistance, poor adhesion to metals, and has poor retort resistance.

The resin composition of the present invention can be used as a vehicle component of paints such as can paints, PCM paints, automobile paints, building material paints, and antirust paints. Among these, it is particularly useful as a vehicle component for can paints.

The resin composition of the present invention may contain conventionally known curing accelerators (for example, acid catalysts such as phosphoric acid and p-toluenesulfonic acid, dryers such as manganese naphthenate and cobalt naphthenate, amines such as trimethylamine and triethylamine). organic peroxides such as benzoyl peroxide), organic solvents (aromatic solvents, aliphatic solvents, ketone solvents, ester solvents, glycol solvents, etc.), plasticizers, pigments, surfactants, A lubricant, furthermore, vinyl acetate resin, vinyl chloride-vinyl acetate copolymer resin, polyester resin, polyvinyl chloride resin, polyolefin resin, polyamide resin, etc. can be added as necessary.

As a method for forming a coating film using the resin composition of the present invention, for example, a solution prepared by dissolving the resin composition in the above-mentioned organic solvent is applied to the surface of a steel plate, an aluminum plate, or a steel plate such as zinc, tin, chromium, etc. Coating is done by coating methods such as roll coating, spray coating, brush coating, dip coating, etc. on metal materials that have been chemically or electrolytically treated with chromic acid, phosphoric acid, etc., on the surface of plated steel plates that have been plated with aluminum, etc. This can be done by baking.

The coating film thickness and baking conditions can be selected as appropriate depending on the application. For example, when applied to a can paint, the dry film thickness is about 2 to 100 μm, preferably about 5 to 50 μm, and the baking conditions are about 220 μm to 100 μm. Baking at 280°C for about 7 to 120 seconds seems to be sufficient. Furthermore, if short-time baking is not required, baking at about 160 to 250° C. for about 30 seconds to 10 minutes seems to be sufficient.

(Action and Effect of the Invention) In the present invention, the polyhydric phenol component which is a component of the resin (A) is a resol type phenol resin (which is a crosslinking agent) (
Because it has excellent compatibility with T3), there is no fear that the two resin components will separate or settle during storage in organic solvents, and exhibits good storage stability.Also, coatings formed from this material cure uniformly. It has excellent processing resistance, adhesion to metals, and scuffing resistance.

In addition, the resin (A) has an excellent balance of properties such as processing resistance, adhesion to metals, and scuffing resistance, since the resin (A) contains a polybutadiene component that imparts flexibility and a polyhydric phenol component that imparts hardness. A coating is formed.

From the above, the resin composition of the present invention has high processing resistance,
It is useful as a vehicle component for can paints and repair paint compositions that require scuff resistance, retort resistance, etc.

(Example) Hereinafter, the present invention will be specifically explained with reference to Examples.

In the examples, "parts" and "1%" indicate "parts by weight" and "% by weight."

The following epoxidized polybutadiene and resol type phenolic resin were used.

Epoxy Butadiene (a) E-1000-8 (manufactured by Nippon Petrochemicals) 1.4-
Butadiene 40%, 1,2-butadiene 60%, oxirane oxygen 8%, molecular weight 1.000 (blE-1800-6,5 (Japan Petrochemicals Co., Ltd. WJ) 1
．． 4-butadiene 40%, 1,2-butadiene 60%,
Oxirane oxygen 6.5%, molecular weight 1.800 (clR-45EPI (manufactured by Idemitsu Petrochemical Co., Ltd.) 1.4-
Butadiene 80%, 1,2-butadiene 20%, oxirane oxygen 7.7%, molecular weight 3.000 (d) E-1000-3,5 (manufactured by Nippon Petrochemicals) 1.
4-butadiene 40%, 1.2-butadiene 60%, oxirane oxygen 3.5%, molecular weight 1.000 (e) BF-1000 (manufactured by Adeka Argus) 1.2-
Butadiene 100%, oxirane oxygen 7.5%, molecular weight 1,000 (f) E-700-6,5 (manufactured by Nippon Petrochemicals) 1.4
-butadiene 40%, 1.2-butadiene 60%, oxirane oxygen 6.5%, molecular weight 700 Resono 1L = -7 25 plates fg) Resol phenol resin Bisphenol A 100 parts, 37% formaldehyde aqueous solution 140 parts, caustic soda 2 of the mixture was added, and the mixture was reacted at 60°C for 3 hours, followed by dehydration at 50°C for 1 hour under reduced pressure.

After that, 85% phosphoric acid and butanol were added, and the solution was filtered to separate the generated sodium phosphate, leaving 60% of the heated residue.
%, a phenolic resin (g) with a viscosity of UV was obtained.

Tamakudo 2.1 (h) 40 parts of epoxy resin solution Epicoat 1009 (manufactured by Yuka Shell Epoxy Co., Ltd., bisphenol A type epoxy resin) was added to Swasol #1
It was dissolved in 60 parts of a mixed solvent of 000 Nibutyl Cellosolve = 1:1 at 40 to 50°C to obtain an epoxy resin solution (HL).

Resin (1) 100 parts of epoxidized polybutadiene (a), 68.4 parts of bisphenol, soo ppm of tetraethylammonium bromide and 100 parts of butyl cellosolve were mixed and dissolved. The mixed solution was reacted at 140° C. for 8 hours to obtain a modified resin having a Gardner viscosity of M, a Herige color number of 3, and an added bisphenol (mol) of 0.18.

Resin ■~■ Epoxidized polybutadiene (a)~(fl) Mix bisphenol A or bisphenol F with the resin in the proportions listed in Table 1, and conduct the reaction under the reaction conditions listed in Table 1.
・Resin ■～■... Obtained a bowl.

Examples 1 to 7 100 parts of resins (solid content) of resins ■ to ■ and resol type phenolic resin (g) were mixed in the formulation (solid content) shown in Table 2, and then Swasol #1000 (manufactured by Cosmo Oil Co., Ltd.) was mixed. ) Nibutyl cellosolve = 1:1 weight ratio) The solid content was adjusted to 50% with a mixed solvent to obtain a composition of an example.

Comparative Examples 1 to 8 The resins were mixed in the formulation shown in Table 2, and then the solid content was adjusted to 50% with a mixed solvent of Swasol #1000 Nibutyl Cellosolve = 1:1 (weight ratio). A composition was obtained.

The paints obtained in Examples and Comparative Examples were baked according to the following method, and the state of the painted surface was observed and physical property tests were conducted.

A tin-plated steel plate with a thickness of 0121 mm was coated with a bar coater to a film thickness of 40 μm, and baked in a conveyor gas furnace for 9 seconds. The conditions of the gas furnace were set so that the plate temperature reached 270° C. after 9 seconds of baking.

Next, using the panels prepared as described above, the coating surface condition (foaming), gel fraction, stickiness of the coating surface, pencil hardness, retort resistance, DuPont impact processability, retort resistance after DuPont impact processing, Various deep drawing workability tests were conducted. The test results are shown in Table-2.

Painted surface condition (foaming) Visually observe the painted surface, and no foaming is observed on the entire painted surface. 0. Only a few small bubbles are observed. ◎. A considerable number of small foams are observed. Δ. A considerable number of large foams are observed. Evaluations were made using criteria such as ``X'' or better.

Cut the gel fraction panel into 10cm x 10c+n, weight Wl (
gr) is measured. Pour MEK into the flask so that MEK (methyl ethyl ketone)/coated plate = 100 d/l OOcm, warm it until it refluxes, start refluxing, add the coated plate, and extract under MEK reflux for 2 hours. Remove the coated plate from the flask. After taking out and drying at 150℃ for 30 minutes and cooling to room temperature, measure the weight w z (grl).
After copying with a mixed solvent of K/cyclohexanone = 50150, dry at 150°C for 30 minutes, and after cooling to room temperature, the weight W (
gr) is measured.

The gel fraction is determined by the following formula.

After baking the paint surface is sticky, cool it down to room temperature, press the paint surface with your finger, and there will be no finger marks at all. 0 There will be very few finger marks. Δ There will be a lot of finger marks on the paint surface. The evaluation was carried out based on the above criteria.

Pencil Hardness The coating hardness of the painted panel was evaluated using a pencil hardness test method based on JIS standards.

Retort resistance (flat plate) Painted panels were immersed in deionized water, treated in an autoclave at 125℃ for 45 minutes, and the whitening state of the paint film was observed.No whitening at all.10Those with severe whitening. ~10).

Retort resistance (impact processed plate) Hitting core 3/8" from the back side of the coating, load 500 gr.

Impact processing was performed at a height of 50 cm, immersed in deionized water, and treated in an autoclave at 125°C for 45 minutes.
The state of peeling of the paint film was observed.

No peeling at all ○ A little peeling Δ Fully peeling × dupont impact workability Hitting core 3/8" from the back side of the coating, load 500 gr.

Impact processing was performed at a height of 50 cm, the processed part was immersed in an aqueous copper sulfate solution, and the degree of copper precipitation was evaluated according to the following criteria.

No copper precipitation is observed O Slight copper precipitation is observed ■ Considerable copper precipitation is observed Δ Copper precipitation is observed on the entire surface of the machined area
*Deep drawing processability A cup was made from the painted panel using an Erichsen deep drawing tester with a blank diameter of 68 um and a punch diameter of 33 m, and the adhesion of the coating film was visually observed.

No abnormality at all Q: Slight peeling Δ: Whole surface peeling

No abnormalities at all ○ Slight layer separation Δ Sedimentation ×

Claims (1)

[Scope of Claims] [1] Essential components include an epoxy group-containing polyhydric phenol-modified epoxidized polybutadiene resin (A) obtained by reacting an epoxidized polybutadiene resin and a polyhydric phenol compound and a resol type phenol resin (B) A resin composition characterized by containing: [2] The epoxidized polybutadiene resin has an oxirane oxygen content of 3 to 12% by weight and a number average molecular weight of 1000 to 1.
0000. The resin composition according to item 1, which is 0000. [3] The resin composition according to item 1, wherein the polyhydric phenol compound is at least one selected from bisphenol A, bisphenol F, and bisphenol B. [4] A coating composition for cans, characterized in that the resin composition according to item 1 is used as a vehicle component.