JPS6210189B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a laminate in which an aqueous sizing agent is coated on an aluminum base material. More specifically, the present invention relates to a laminate using an aqueous sizing agent that has excellent adhesion to an aluminum base material and a top coating agent, and has excellent processability. BACKGROUND ART Aluminum plates or sheets have traditionally been used for various purposes such as nameplates and decorative plates due to their excellent performance such as light weight, excellent workability, and beautiful surfaces. In these applications, sizing processing is usually applied to the aluminum surface for the purpose of preventing scratches on the surface and improving adhesion of ink and paint. Sizing agents currently widely used include those based on resins such as polyurethane, epoxymelamine, vinyl, and various alkyds, such as short oil, medium oil, and long oil alkyds, and can be used depending on the purpose. ing. On the other hand, aluminum plates or sheets that have been subjected to these sizing processes are cut or bent before and after the top coating process of ink, paint, etc., but the processability of these processes is poor, and cracks and cracks may occur in the processed parts.
Defects such as lifting are likely to occur. Furthermore, the adhesion to ultraviolet curable or electron beam curable inks and paints is very poor. Furthermore, in recent years, there have been strong social demands for resource saving, energy saving, pollution-free, etc., and there are particularly high expectations for water-based resins. However, thermoplastic aqueous resins such as acrylic and vinyl acetate resins have poor adhesion and water resistance. Crosslinking may be considered as a means of improving water resistance, but this is not preferable because the adhesiveness is extremely reduced. In other words, the reality is that there is no water-based resin that has excellent processability, adhesion, and water resistance and can be put to practical use. Therefore, it is desired to develop an aqueous sizing agent that has excellent processability such as cutting or bending, adhesion, and water resistance. Therefore, the present inventors have conducted research on water-based sizing agents that are excellent in processability, adhesion, and water resistance, and have finally arrived at the present invention. That is, the present invention is a laminate comprising an aluminum base material, a film obtained by coating and drying the aqueous sizing agent described below on the base material, and an overcoat layer provided on the film. Aqueous sizing agent: (A) 0.5 to 10 mol% of the polycarboxylic acid component
is a sulfonic acid metal group-containing dicarboxylic acid and has a melting point of 70 to 200°C and/or (B) polycarboxylic acid component, 0.5
Contains an amorphous polyester resin with a softening point of 40 to 200°C in which ~10 mol% is a dicarboxylic acid containing a sulfonic acid metal group, (C) a water-soluble organic solvent with a boiling point of 60 to 200°C, and (D) water. , and (A), (B), (C) and (D)
satisfies the following formulas (1), (2) and (3). Formula (1): (A) / (B) = 0 ~ 100 / 100 ~ 0 (weight ratio) Formula (2): ((A) + (B)) / (C) / (D) = 1 ~ 70 /0~40/20~99 (weight ratio) Formula (3): (C)/((C)+(D)) = 0~66/100 (weight ratio) The above aqueous sizing agent is used in the present invention. As a result, a laminate with excellent adhesion, processability, and water resistance can be obtained. In addition to untreated aluminum, the aluminum base materials used in the present invention include hairline-treated,
Examples include aluminum that has been subjected to various treatments such as sandblasting, alumite treatment, and chemical polishing. The shape of the aluminum base material is generally a flat plate, but is not particularly limited. Further, as the top coating agent used in the present invention, there are inks such as solvent-based, water-based, and photocurable offset inks, gravure inks, and screen inks. Also, from the viewpoint of protecting the printed surface, a solvent type top coating agent (acrylic type, etc.) is sometimes used. The aqueous sizing agent used in the present invention is (A) a crystalline polyester resin containing a metal sulfonate base, (B) an amorphous polyester resin containing a metal base sulfonate, and (C) a metal base-containing amorphous polyester resin.
This is a stable aqueous sizing agent for hydrophobic resins obtained by blending a water-soluble organic compound with a boiling point of 60 to 200°C and (D) water in a specific ratio. The aqueous sizing agent thus obtained provides a coating film with excellent processability, adhesion and water resistance. Next, the aqueous sizing agent used in the present invention will be explained in detail. In the crystalline or amorphous polyester resin of the present invention, the sulfonic acid metal group-containing aromatic dicarboxylic acid accounts for 0.5 to 10 mol % of the polycarboxylic acid component. Specifically, the polycarboxylic acid component is an aromatic dicarboxylic acid containing no sulfonic acid metal base.
99.5 mol% aliphatic or cycloaliphatic dicarboxylic acid
59.5 to 0 mol% and 0.5 to 10 mol% of an aromatic dicarboxylic acid containing a sulfonic acid metal group, and the polyol component consists of an aliphatic glycol having 2 to 8 carbon atoms or/and an alicyclic glycol having 6 to 12 carbon atoms. A polyester resin having a molecular weight of 2,500 to 30,000 is preferable. Examples of aromatic dicarboxylic acids that do not contain sulfonic acid metal groups include terephthalic acid, isophthalic acid, orthophthalic acid, and 2,6-naphthalenedicarboxylic acid. The aromatic dicarboxylic acid containing no sulfonic acid metal group preferably accounts for 40 to 99.5 mol % of the polycarboxylic acid component. If it is less than 40 mol%, the mechanical strength and water resistance of the polyester resin will be poor, which is not preferable. If it exceeds 99.5 mol%, the polyester resin will no longer be dispersed in the system. Examples of aliphatic or alicyclic dicarboxylic acids include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dimer acid, tetrahydrophthalic acid, hexahydrophthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, etc. can be mentioned. Aliphatic or alicyclic dicarboxylic acids are polycarboxylic acid components of 59.5~
Preferably it is 0 mol%. If it exceeds 59.5 mol%, water resistance and coating strength will decrease and tackiness will appear. Furthermore, P-hydroxybenzoic acid, P-
(2-hydroxyethoxy)benzoic acid or hydroxypivalic acid, γ-butyrolactone, ε-
Caprolactone or the like can be used if necessary. If necessary, a trifunctional or higher functional polycarboxylic acid such as trimellitic acid or pyromellitic acid may be used in an amount of 10 mol % or less based on the total polycarboxylic acid component. Examples of aliphatic glycols having 2 to 8 carbon atoms include ethylene glycol, propylene glycol, 1,3
-Propanediol, 1,4-butanediol,
Neopentyl glycol, 1,5-pentanediol, diethylene glycol, 1,6-hexanediol and the like can be mentioned. Carbon number 6-12
Examples of the alicyclic glycol include 1,4-cyclohexanedimethanol and the like. The amount of aliphatic glycol having 2 to 8 carbon atoms and/or alicyclic glycol having 6 to 12 carbon atoms is 90 to 100 mol % based on the total polyol component. If necessary, trimethylolpropane, trimethylolethane, glycerin, pentaerythritol, and other trifunctional or higher functional polyols may be added to the total polyol component.
It may be 10 mol% or less. In addition, the molecular weight is 500
~5,000 polypropylene glycol and polytetramethylene glycol may be used as long as it is 40% by weight or less based on the total polyol components, and polyethylene glycol with a molecular weight of 150 to 10,000 may also be used at 20% by weight based on the total polyol components. below,
It can be used preferably in an amount of 10% by weight or less. Examples of aromatic dicarboxylic acids containing sulfonic acid metal bases include metal salts such as sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, and 5[4-sulfophenoxy]isophthalic acid. can be given. Metal salts include Li, Na, K, Mg, Ca,
Examples include salts such as Cu and Fe. Particularly preferred are 5-sodium sulfoisophthalic acid, 5
-Potassium sulfoisophthalate. The amount of the aromatic dicarboxylic acid containing a sulfonic acid metal group is 0.5 to 10 mol % based on the total polycarboxylic acid components, preferably 1 to 7 mol % based on the total polycarboxylic acid components. When no sulfonic acid metal group-containing aromatic dicarboxylic acid is used, the polyester resin has very poor dispersibility in water. As the amount of the metal base-containing aromatic dicarboxylic acid increases, better dispersibility is exhibited. However, when the amount exceeds 10 mol%, the resulting polyester resin has good dispersibility in water, but the water resistance of the film obtained after coating and drying becomes very poor, as well as the adhesion. Sexuality also becomes inferior. The crystalline polyester resin of the present invention has a melting point of 70~
The temperature is 200°C, particularly preferably 90-180°C. If the melting point of the crystalline polyester resin is less than 70°C, the resulting film will have insufficient water resistance. on the other hand,
If the melting point exceeds 200°C, the dispersibility in water will be poor. The crystalline polyester resin in the present invention is
It is necessary to have a heat of crystal fusion of 50 cal or more, preferably 100 to 1500 cal, and the heat of crystal fusion is
If it is less than 50 cal, water resistance, especially hot water resistance, will be poor. The amorphous polyester resin of the present invention has a softening point of 40
-200°C, preferably 60-180°C. When the softening point of the amorphous polyester resin is less than 40°C, the resulting film has poor water resistance and becomes sticky. On the other hand, if the softening point exceeds 200°C, the dispersibility in water becomes poor. The molecular weight of the crystalline or amorphous polyester resin of the present invention is 2500 to 30000, preferably 3000 to 20000.
It is. When the molecular weight of the polyester resin is less than 2500, not only the water resistance is insufficient, but also the adhesion and processability are poor. On the other hand, if the molecular weight exceeds 30,000, the dispersibility in water will be poor. The water-soluble organic compound used in the present invention is an organic compound having a solubility in water of 20 g or more at 20°C, and specific examples thereof include aliphatic and alicyclic alcohols, ethers, esters, and ketone compounds. It will be done. Specifically, for example, methanol,
Ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-
Monohydric alcohols such as butanol and tert-butanol, glycols such as ethylene glycol and propylene glycol, methyl cellosolve, ethyl cellosolve, isopropyl cellosolve, tert-butyl cellosolve, n-butyl cellosolve, 3-methyl-3-methoxybutanol, n- Glycol derivatives such as butyl cellosolve acetate, ethers such as dioxane and tetrahydrofuran, esters such as ethyl acetate, methyl ethyl ketone,
These include ketones such as cyclohexanone, cyclooctanone, cyclodecanone, and isophorone. Particularly preferred are n-butyl cellosolve, tert-butyl cellosolve, isopropyl cellosolve, ethyl cellosolve, isopropanol and the like. These water-soluble organic compounds can be used alone or in combination of two or more. The boiling point of these water-soluble organic compounds needs to be in the range of 60 to 200°C. If the boiling point does not reach 60°C, it is difficult to maintain a temperature sufficient to mix or dissolve the polyester resin in this organic compound. Furthermore, the boiling point
When the temperature exceeds 200°C, the resulting water-based sizing agent cannot be quickly dried after application. The aqueous sizing agent in the present invention includes (A) crystalline polyester resin, (B) amorphous polyester resin, and (C)
Mix water-soluble organic compounds in advance at 50 to 200℃ and add (D) water or (A), (B), and (C).
The mixture is added to water and stirred at 40-120°C. Alternatively, it can also be produced by adding the polyester resins (A) and (B) into a mixed solution of (D) water and (C) a water-soluble organic compound, and stirring and dispersing it at 40 to 100°C. Ru. In either method, the blending ratio of (A) crystalline polyester resin, (B) amorphous polyester resin, (C) water-soluble polymer compound, and (D) water is important in maintaining the performance of the water-based sizing agent. is an element, and formula (1),
It is necessary to satisfy the mixing ratios of (2) and (3). Formula (1): (A) / (B) = 0 ~ 100 / 100 ~ 0 (weight ratio) Formula (2): ((A) + (B)) / (C) / (D) = 1.0 ~ 70 /0~40/20~99 (weight ratio) Formula (3): (C)/((C)+(D)) = 0~66/100 (weight ratio) The polyester resin contained in the aqueous dispersion is ( Both A) a crystalline polyester resin and (B) an amorphous polyester resin may be included, and each may be used alone. When the blending ratio of (A) crystalline polyester resin and/or (B) amorphous polyester resin contained in the aqueous sizing agent does not reach 1.0% by weight, or
If it exceeds 70% by weight, the viscosity of the aqueous sizing agent becomes too low or too high, which is not preferable. If the blending ratio of the water-soluble organic compound (C) contained in the aqueous sizing agent exceeds 40% by weight, drying properties will deteriorate, which is undesirable. Particularly preferably, the blending ratio of the water-soluble organic compound (C) is 80% by weight or less. The aqueous sizing agent of the present invention can be used as it is, but it can be further mixed with one or more compounds selected from the group of amino resins, epoxy compounds, and isocyanate compounds as crosslinking agents. Examples of amino resins include urea, melamine,
Formaldehyde adducts such as benzoguanamine,
Furthermore, alkylation with an alcohol having 1 to 6 carbon atoms can be mentioned. Further, if necessary, a favorable effect can be achieved by using formalin in combination. Epoxy compounds include bisphenol A diglycidyl ether and its oligomer, hydrogenated bisphenol A diglycidyl ether and its oligomer, orthophthalic acid diglycidyl ester, isophthalic acid diglycidyl ester,
Terephthalic acid diglycidyl ester, p-oxybenzoic acid glycidyl ester ether, tetrahydrophthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, succinic acid diglycidyl ester, adipic acid diglycidyl ester, sebacate diglycidyl ester, ethylene Glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-
Butanediol diglycidyl ether, 1,6-
Hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate, 1,4-diglycidyloxybenzene, diglycidyl dimethylhydantoin, diglycidyl ethylene urea, diglycidyl propylene urea, glycerol Examples include polyglycidyl ether, trimethylolethane polyglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, and polyglycidyl ether of a glycerol alkylene oxide adduct. Furthermore, as the isocyanate compound, aromatic, aliphatic, araliphatic diisocyanates, 3
There are polyisocyanates with higher than valance, and they can be either low molecular compounds or high molecular compounds. for example,
Isocyanate compounds such as tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, isophorone diisocyanate trimer, or these Excess amounts of isocyanate compounds, such as ethylene glycol, propylene glycol, trimethylolpropane,
glycerin, sorbitol, ethylenediamine,
Compounds containing terminal isocyanate groups obtained by reacting low-molecular active hydrogen compounds such as monoethanolamine, diethanolamine, and triethanolamine, or high-molecular active hydrogen compounds such as various polyether polyols, polyester polyols, and polyamides, etc. can be mentioned. The isocyanate compound may be a blocked isocyanate. Examples of the isocyanate blocking agent include phenols such as phenol, thiophenol, methylthiophenol, ethylphenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; oximes such as acetoxime, methyl ethyl ketone oxime, and cyclohexanone oxime; methanol; Alcohols such as ethanol, propanol, butanol, halogen-substituted alcohols such as ethylene chlorohydrin, 1,3-dichloro-2-propanol, tertiary alcohols such as t-butanol, t-pentanol, t-butanethiol, etc. class, ε-caprolactam, δ-
Examples include lactams such as valerolactam, τ-butyrolactam, and β-propyllactam, as well as aromatic amines, imides, active methylene compounds such as acetylacetone, acetoacetate, and malonic acid ethyl ester, mercaptans, and imines. ureas, diaryl compounds, sodium bisulfite, and the like. The blocked isocyanate can be obtained by subjecting the above-mentioned isocyanate compound and an isocyanate blocking agent to an addition reaction by a conventionally known appropriate method. A curing agent or an accelerator can also be used in combination with these crosslinking agents. The crosslinking agent can be mixed with (A) crystalline polyester resin or (B) amorphous polyester resin, mixed directly with aqueous sizing agent, or mixed with (C) water-soluble organic compound or (D) in advance. There are methods such as dissolving or dispersing it in a mixture with water, and any method can be selected depending on the type of crosslinking agent. The aqueous sizing agent of the present invention exhibits unprecedented processability, adhesion, and water resistance. The aqueous sizing agent of the present invention includes pigments, dyes,
Various additives can be added. The laminate of the present invention is usually obtained by coating the aqueous sizing agent on an aluminum base material and drying it to obtain a film, and then applying a top coat onto the film and drying it. The aqueous sizing agent layer and topcoat layer may be provided simultaneously. A roll coater is usually used to apply the aqueous sizing agent and topcoat. It may also be applied by screen printing. In addition, the drying method for water-based sizing agents and topcoating agents is air drying or forced drying (e.g. 100℃ at 70℃).
2 minutes at 100℃, 1 minute at 150℃, etc. For baking type, 5 to 30 minutes at 100-200℃. )
and so on. Furthermore, after applying a sizing agent to the aluminum base material, processing such as bending may be performed.
Processing may be performed after providing an overcoat layer. By using the above water-based sizing agent, the laminate of the present invention has excellent adhesion to a base material, processability, and water resistance, and can be used for various purposes. EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples. In the examples, parts simply indicate parts by weight. Evaluation of various properties was performed according to the following methods. (1) Molecular weight Measured using a molecular weight measuring device (Hitachi Model 115). (2) Crystal melting point and heat of crystal fusion Measured using a differential scanning calorimeter (manufactured by Shimadzu Corporation) at a heating rate of 10° C./min. (3) Softening point Fully automatic melting point measuring device (manufactured by METTLER,
The measurement was carried out using MODEL FP-1). (4) Particle size of aqueous dispersion Measured using a grindmeter and an optical microscope. (5) Adhesion Conforms to ASTM-3359. (6) Water resistance Conforms to JIS 5400. (7) Film hardness Compliant with JIS K 5400. (8) When bending a painted aluminum plate by 180°, an untreated aluminum plate was inserted and processed, and workability was evaluated by the number of untreated aluminum plates when lifting or cracking occurred in the processed area. Example: 5T means that when five untreated aluminum plates are inserted, there will be no cracks or floating in the processed area.
If four sheets are inserted, cracks or floating will occur. 0T means that no cracks or lifting will occur even if untreated aluminum plates are processed without being inserted. Production example 1 475 parts of dimethyl terephthalate, 466 parts of dimethyl isophthalate, 45 parts of dimethyl 5-sodium sulfoisophthalate, 443 parts of ethylene glycol
parts, 400 parts of neopentyl glycol, zinc acetate
Charge 0.44 parts of sodium acetate, 0.05 parts of sodium acetate, and 0.43 parts of antimony trioxide into a reaction vessel, and heat at 140°C to 220°C.
The transesterification reaction was carried out over a period of 4 hours. Next, while raising the temperature to 260°C, the pressure inside the reaction system was gradually reduced to 5 mmHg after 1 hour. And finally
A polycondensation reaction was carried out at 260°C for 1 hour under reduced pressure of 0.1 to 0.3 mmHg to obtain an amorphous polyester resin (A-3) having a molecular weight of 7000 and a softening point of 152°C. As a result of compositional analysis such as NMR, the composition of polyester resin (A-3) is 49 mol% terephthalic acid, 48 mol% isophthalic acid, 3 mol% 5-sodium sulfoisophthalic acid, 52 mol% ethylene glycol, and neopentyl glycol. It was 48 mol%.
Further, the heat of crystal fusion of the polyester resin was measured using a differential scanning calorimeter, but no endothermic peak was observed. Furthermore, amorphous polyester resins (A-2) to (A-7), crystalline polyester resins (B-1), (B- 2) was obtained. Their characteristic values were as shown in Tables 1-1 and -2.

【table】

【table】

[Table] Example 1 100 parts of amorphous polyester resin (A-1) and 40 parts of n-butyl cellosolve were placed in a container.
After stirring at 130°C for about 3 hours to obtain a uniform and viscous melt, 360 parts of water was gradually added while stirring.
After about 1 hour, a homogeneous pale bluish-white aqueous sizing agent () was obtained. The obtained aqueous sizing agent was applied onto an untreated aluminum plate with a thickness of 1.0 mm using a bar coater #10 so that the solid film thickness was 1.0 μ, and then
It was dried at 100°C for 5 minutes. The resulting film had good adhesion and workability, and exhibited water resistance without whitening even after being immersed in water for 7 days. Furthermore, when we printed red and black ultraviolet curing ink on a sized aluminum plate, the adhesion of both red and black inks was 100/100.
It was very good. Examples 2 to 4, Comparative Examples 1 to 4 Aqueous sizing agents () to () were obtained in the same manner as in Example 1 using the formulations shown in Table 2. Table 3 shows the performance of the films obtained from these aqueous sizing agents () to (). For comparison, aqueous sizing agents (-) were obtained in the same manner as in Example 1 using the formulations shown in Table 2. The performance of the obtained film is shown in Table 3.

【table】

[Table] Example 5 100 parts of aqueous sizing agent () and amino resin,
A film was formed on an untreated aluminum plate in the same manner as in Example 1 except that 5 parts of Sumimaru M-30W (manufactured by Sumitomo Chemical Industries, Ltd.) was used. The performance of the obtained film is shown in Table 4. Comparative Example 5 A film was obtained on an untreated aluminum plate in the same manner as in Example 5, except that the aqueous sizing agent (2) was used instead of the aqueous sizing agent (2). The performance of the obtained film is shown in Table 4.

[Table] Comparative Example 6 On an untreated aluminum plate in the same manner as in Example 5 except that an epoxy melamine solvent-based sizing agent, S-77-600 (manufactured by Toyo Ink) was used instead of the water-based sizing agent (). A coating film was obtained. The performance of the obtained film is as follows.

【table】

【table】

Claims (1)

[Scope of Claims] 1. A laminate comprising an aluminum base material, a film obtained by coating and drying the following aqueous sizing agent on the base material, and a top coat layer provided on the film. Aqueous sizing agent: (A) 0.5 to 10 mol% of the polycarboxylic acid component
is a sulfonic acid metal group-containing dicarboxylic acid and has a melting point of 70 to 200°C and/or (B) polycarboxylic acid component, 0.5
Contains an amorphous polyester resin with a softening point of 40 to 200°C in which ~10 mol% is a dicarboxylic acid containing a sulfonic acid metal group, (C) a water-soluble organic solvent with a boiling point of 60 to 200°C, and (D) water. , and (A), (B), (C) and (D)
satisfies the following formulas (1), (2) and (3). Formula (1): (A) / (B) = 0 ~ 100 / 100 ~ 0 (weight ratio) Formula (2): ((A) + (B)) / (C) / (D) = 1 ~ 70 /0~40/20~99 (weight ratio) Formula (3): (C)/((C)+(D)) = 0~66/100 (weight ratio)