JP2019077090A - Coated metal plate - Google Patents

Abstract

To provide a coated metal plate having a coating layer having high versatility to various coating materials and ink.SOLUTION: A coated metal plate has at least a metal plate, a first coating layer, a second coating layer and an active energy ray-curable resin layer in this order, in which the second coating layer contains a polyester resin as a main component, and the polyester resin has an alicyclic hydrocarbon structure.SELECTED DRAWING: None

Description

  The present invention relates to a coated metal plate, and more particularly to a coated metal plate having excellent printing properties.

  2. Description of the Related Art Conventionally, various applications have been made to metal plates used for outer plates of electric appliances and the like in order to enhance design, and coating processes have been applied to metal plates to facilitate application. Such a coating process is required to have a property of satisfying both adhesion to metal and adhesion to paint and ink since the substrate is metal, and a method of laminating a plurality of layers having different properties Have been adopted (patent documents 1 to 3).

Unexamined-Japanese-Patent No. 11-138690 Patent Document 1: Japanese Patent Application Publication JP, 2016-199034, A

  On the other hand, there are many types of paints and inks for enhancing the designability, and there is a demand for coating processing that can be applied to all of them. In particular, when the substrate is a metal plate, adhesion with paints and various inks It has not been possible to realize coating processing that can ensure the properties.

  An object of the present invention is to provide a coated metal plate having a highly versatile coating layer for various paints and inks.

  The object of the present invention is achieved by the following.

(1) A coated metal plate having at least a metal plate, a first coating layer, a second coating layer, and an active energy ray curable resin layer in this order, wherein the second coating layer contains a polyester resin as a main component, A coated metal sheet, wherein the polyester resin has an alicyclic hydrocarbon structure.
(2) The coated metal sheet according to the above 1, wherein the second coated layer contains a crosslinked product of a polyester resin and a melamine resin.
(3) The coated metal sheet according to the above 1 or 2, wherein the first coating layer contains a crosslinked product of a polyester resin and a melamine resin.

  According to the present invention, it is possible to obtain a coated metal plate having a highly versatile coating layer for various paints and inks.

Hereinafter, embodiments of the present invention will be described in detail.
The coated metal sheet of the present invention is a coated metal sheet having at least a metal sheet, a first coated layer, a second coated layer and an active energy ray curable resin layer in this order, and the second coated layer is a polyester resin. Is a main component, and the polyester resin has an alicyclic hydrocarbon structure.

<Second covering layer>
The main component of the second covering layer of the present invention is a polyester resin. Here, the main component means a component having the largest mass% contained among the components constituting the continuity of the layer of the second covering layer, preferably 30 to 90 mass%.

«Polyester resin with alicyclic hydrocarbon structure»
The polyester resin of the present invention has an alicyclic hydrocarbon structure. The alicyclic hydrocarbon structure may be present in any of the dicarboxylic acid component forming the polyester resin and the diol. As a dicarboxylic acid component, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 4,4'-bicyclohexyldicarboxylic acid, and It can introduce | transduce by selecting these derivatives etc. or its acid anhydride.

  As the diol, it is introduced by selecting 1,4-cyclohexanedimethanol, 1,4-cyclohexanediol, 1,3-cyclopentadimethanol, 4,4'-bicyclohexyldimethanol, derivatives thereof, etc. be able to.

  Although the effect of the present invention is exhibited by introducing even a slight amount of the dicarboxylic acid component having such an alicyclic hydrocarbon structure and the diol, each of 5 mol% or more, preferably 30 mol% or more is introduced. As an alicyclic hydrocarbon structure, a cyclohexane structure is preferable.

As other components of the dicarboxylic acid component and the diol, known aromatic and aliphatic dicarboxylic acid components and diols can be used.
A plurality of polyester resins of the present invention may be used, or may be mixed with other polyester resins not having an alicyclic hydrocarbon structure.

  The polyester resin of the present invention can be polymerized by a commonly known method. As a number average molecular weight, it is 1000-100000, Preferably it is 2000-50000. The thing of 1-100 mgKOH / g of hydroxyl values can be selected suitably, and 5-80 mgKOH / g is preferable. The glass transition temperature (Tg) is 1 to 60 ° C, preferably 10 to 50 ° C.

  The number average molecular weight was measured by GPC in terms of standard polystyrene. Moreover, Tg was measured by DSC.

«Melamine resin»
It is preferable that the 2nd coating layer of this invention is made to contain and harden | cure melamine resin as a hardening | curing agent. As the melamine resin, a part or all of the methylol group of methylolated melamine is a monohydric alcohol having 1 to 8 carbon atoms, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, Examples thereof include partially etherified or fully etherified melamine resins etherified with i-butyl alcohol, 2-ethyl butanol, 2-ethyl hexanol and the like. These may be used in which all methylol groups are etherified or partially etherified, and methylol groups and imino groups remain.

  There may be mentioned alkyletherified melamines such as methyletherified melamine, ethyletherified melamine and butyletherified melamine, and only one kind may be used or, if necessary, two or more kinds may be used in combination. Among them, methyletherified melamine resin in which at least a part of methylol group is alkyletherified is preferable.

  As a commercial item of such a melamine resin, Cymel series (made by Nippon Cytec Industries, Ltd.), Yuvan 20SE60 (made by Mitsui Chemicals, Inc., a brand name, the average degree of polymerization exceeds 3), etc. are mentioned. Among these, melamine resins in which a hydrophilic group (for example, an imino group) does not remain are preferable for improving the corrosion resistance. For example, combined use of methyl etherified melamine resins is good for improving the corrosion resistance.

As a curing catalyst, an acid catalyst such as a sulfonic acid compound or an amine neutralized product of a sulfonic acid compound may be used.
The melamine resin is preferably contained in an amount of 1 to 99 parts by mass, more preferably 5 to 50 parts by mass, with respect to 100 parts by mass of the polyester resin.
Other known curing agents may include epoxy resins, blocked isocyanates, and polyurethane resins.

«Pigment particles»
The polyester resin of the present invention may contain pigment particles to form a second covering layer. The pigment particles include inorganic pigment particles and organic pigment particles.
Examples of inorganic pigment particles include white pigment particles such as titanium oxide and zinc flower, blue pigment particles, green pigment particles, red pigment particles, yellow pigment particles, black pigment particles, aluminum powder, copper powder, nickel powder, titanium oxide coating Bright pigment particles such as mica powder, iron oxide-coated mica powder and bright graphite; and extender pigment particles such as clay, talc, barta, calcium carbonate, silica; and the like. In addition, it is also possible to use Fe-Cr inorganic complex oxide pigment particles and Bi-Mn inorganic complex oxide pigment particles that reflect infrared light.

  Examples of organic pigment particles include fluorine resins such as polyvinylidene fluoride and polytetrafluoroethylene, polyamides, acrylic resins, polyurethanes, phenol resins, silicone resins, polypropylene, and polyamides such as nylon 11 and nylon 12, etc. it can.

  The pigment particles are not components constituting the continuity of the layer of the second covering layer, but it is preferably contained in an amount of 1 to 200 parts by mass, preferably 1 to 150 parts by mass, with respect to 100 parts by mass of the polyester resin.

«Other additives»
The second coating layer of the present invention may contain additives such as an ultraviolet light absorber, a light resistant agent, and an antistatic agent.
«Formation method»
The second coating layer of the present invention can be formed by coating and drying a coating solution in which a polyester resin or a melamine resin is dissolved.

«Solvent»
As a solvent used for the coating liquid for forming a 2nd coating layer, what can melt | dissolve or disperse | distribute components, such as a polyester resin, can be used, Specifically, For example, toluene, xylene, high boiling point petroleum-based carbonization Hydrocarbon solvents such as hydrogen, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and isophorone, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate and diethylene glycol monoethyl ether acetate, methanol and ethanol Alcohol solvents such as butanol, ether alcohol solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, water, etc. These may be used alone or in combination of two or more.
The coating solution has a solid content concentration of 20 to 90% by mass, preferably 30 to 80% by mass.

<< application drying >>
The coating and drying is performed by curtain coating or roll coating so that the film thickness after drying and curing becomes 5 to 30 μm, preferably 10 to 20 μm, and within the range of 15 to 180 seconds at 160 to 250 ° C. A dried coating is formed by baking and drying under conditions of -230 ° C. and in the range of 20 to 120 seconds.

<Metal plate>
The metal plate of the present invention is iron, aluminum alloy, brass, copper plate, stainless steel plate, tin plate, galvanized steel plate, alloyed zinc (such as Zn-Al, Zn-Ni, Zn-Fe) plated steel plate, aluminum plated steel plate And the like, and a surface-treated metal plate in which the surface of the metal plate is subjected to a conversion treatment such as phosphate treatment or chromate treatment.

In addition to the above metal plate, using a resin composite metal plate having a layer configuration of “metal plate / adhesive layer / resin layer / adhesive layer / metal plate” having a metal plate in the outermost layer on one side or both sides it can.
In addition, a resin composite metal plate in which the surface of a nonmetal substance such as resin is covered with a metal layer by vapor deposition or the like can also be used as a metal plate, and the resin is further melted and sandwiched between the resin composite metal plates The one having “resin layer / metal plate” can also be used as a metal plate.
Although the thickness of a metal plate can be arbitrarily selected by a use location, it is preferable that it is 10-1500 micrometers.

<First covering layer>
The first covering layer of the present invention has a role as a subbing layer of the second covering layer. Although a known material that can be used for the metal plate surface can be used for the undercoat layer, a cured reaction product of a polyester resin and a melamine resin is preferable. Also, it may be a urea resin containing a blocked isocyanate and a polyamine, or a polyester resin crosslinked with a urea resin and a melamine resin. The formation method can be the same as the formation of the second covering layer.
The dry film thickness is preferably 1 to 50 μm.

«Chemical conversion treatment»
The metal plate is also preferably subjected to a chemical conversion treatment as a pre-application treatment of the first covering layer. Chemical conversion treatment is performed by known chemical conversion treatment. Examples of the treatment agent (chemical conversion treatment agent) for chemical conversion treatment include chromium such as chromate treatment agent, trivalent chromic acid treatment agent, chromate treatment agent containing resin, trivalent chromic acid treatment agent containing resin, etc. Treatment agents, zinc phosphate treatment agents, phosphate treatment agents such as iron phosphate treatment agents; oxide treatment agents containing metal oxides such as cobalt, nickel, tungsten and zirconium singly or in combination, Treatment agents containing inhibitor components that prevent corrosion, treatment agents in which a binder component (organic, inorganic, organic-inorganic composite, etc.) and inhibitor component are complexed, treatment agents in which an inhibitor component and metal oxide are complexed, binder component and Treatment agents in which silica, titania, sols such as zirconia are complexed, treatment agents in which the components of the treatment agent exemplified above are further complex, etc. are mentioned. .

  The chemical conversion treatment can be carried out using a chemical conversion treatment agent by a known method such as a roll coating method, a spray method, an immersion method, an electrolytic treatment method or an air knife method. After the chemical conversion treatment, steps such as drying at a normal temperature or drying with a heating device such as a hot air furnace, an electric furnace, or an induction heating furnace may be added as necessary. You may apply the curing method by energy rays, such as infrared rays, ultraviolet rays, and electron beams.

<Active energy ray curable resin layer>
The present invention further comprises an active energy ray-curable resin layer on the second covering layer. The active energy ray curable resin layer is cured by irradiation of active energy rays such as ultraviolet rays. As a light source of the active energy ray, it is preferable to use a high pressure mercury lamp, a metal halide lamp, an LED or the like. The active energy ray-curable resin layer does not have to be uniform as a layer, and may be present as a lens-like molded article formed by the active energy ray-curable inkjet ink composition.

  Known materials can be used for the active energy ray curable resin layer of the present invention, but (A) a compound having a (meth) acryloyl group or a vinyl ether group in the molecule, and (B) a photopolymerization initiator It is preferable that it is a hardened | cured material of the composition which it has. Examples of these materials include compounds described in paragraphs (0012) to (0023) of JP-A-2015-77765, and compounds described in paragraphs (0013) to (0042) of JP-A-2016-194063. It can be mentioned.

  Examples of the photopolymerization initiator include known benzophenone compounds, acetophenone compounds, thioxanthone compounds, phosphine oxide compounds and the like, but from the viewpoint of curability, the wavelength of the active energy ray to be irradiated and the photopolymerization initiator It is preferable that the absorption wavelengths of R and R overlap as much as possible.

  You may further contain coloring agents, such as a dye and a pigment. In order to heat the printing layer after active energy ray irradiation, a pigment is preferable, and C.I. I. Pigment Black 7, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 15: 4, C.I. I. Pigment Blue 28, C.I. I. Pigment Red 101, C.I. I. Pigment Red 122, C.I. I. Pigment Red 202, C.I. I. Pigment Red 254, C.I. I. Pigment Red 282, C.I. I. Pigment Violet 19, C.I. I. Pigment White 6, C.I. I. Pigment White 7, C.I. I. Pigment Yellow 42, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 138, C.I. I. Pigment Yellow 139, C.I. I. Pigment Yellow 150, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 213, C.I. I. Pigment Green 7, C.I. I. Pigment Green 36 etc. is mentioned suitably. Other common additives and solvents can be used.

  In the ink composition of the present invention, the content of the colorant is, for example, 0.1 to 20% by mass, and preferably 1 to 17% by mass from the viewpoints of coloring properties, ejection stability of the ink, and the like. Moreover, a coloring agent may be used individually by 1 type, and may be used in combination of 2 or more types.

  In another preferable example of the inkjet ink composition forming the active energy ray-curable resin layer of the present invention, the ink viscosity at 40 ° C. is 5 mPa · s or more and less than 20 mPa · s.

The method for producing an active energy ray-curable resin layer according to the present invention comprises the steps of: discharging the above-mentioned active energy ray-curable ink jet ink composition onto the second coating layer by an inkjet printer; And, if necessary, heating to cure the layer. The discharge amount is appropriately determined by the performance required for the coated metal plate, and may be a plurality of discharge steps.
In addition, the coated metal plate of the present invention may be provided with a protective layer on the active energy ray curable resin layer, and may be provided with a layer on the opposite surface.

  Hereinafter, the present invention will be more specifically described by way of examples and comparative examples. In the following, “parts” and “%” are all based on weight.

<Synthesis of Polyester Resin-Synthesis Example P1>
In a four-necked flask equipped with a reflux apparatus capable of separating water, 40 mol% of cyclohexanedimethanol (CHDM), 30 mol% of ethylene glycol (EG), 30 mol% of neopentyl glycol (NPG), hexahydrophthalic anhydride (HHPA 60% by mole, 40% by mole of isophthalic acid (IPA) and a small amount of an antifoaming agent, heated and stirred to 160 ° C over 4 hours from 160 ° C to 240 ° C, and then the acid value is 3 mg KOH / g The dehydration condensation reaction was carried out at 240 ° C. until reaching Thereafter, the heating is stopped, cooling is carried out, and dilution with a mixed solution of cyclohexanone / sorbesso 150 = 50/50 is carried out while paying attention to reflux of the solvent, nonvolatile content 40%, hydroxyl value 6 mg KOH / g, number average molecular weight A polyester resin solution of 18,000 was obtained.

Synthesis Example P2-8
The synthesis was performed in the same manner as in Synthesis Example P1 except that the composition was changed as shown in Table 1 below in Synthesis Example P2 to 8 to obtain each polyester resin. In addition to the above, adipic acid (AA) was used as a polybasic acid for P5-7.

<Preparation of Coating to Form Second Coating Layer>
The various polyester resins thus obtained, the crosslinking agent, and the Ti-containing oxide were mixed in accordance with the following procedure to prepare a coating agent having the composition (in terms of solid content) shown in Table 2.
A part of the polyester resin was charged, a pigment (Ti-containing oxide) and cyclohexanone were added, and the mixture was uniformly dispersed in a dispersing machine to confirm that the particle diameter of the pigment became 20 μm or less using a particle gauge.

  Next, the remainder of the polyester resin and the crosslinking agent were added and dispersed to obtain a dispersion. Furthermore, in order to improve the film forming property, an antifoaming agent (Polyflow 90, manufactured by Kyoeisha Chemical Co., Ltd.) which is 0.3% by mass of the whole coating agent is added to the obtained dispersion, and cyclohexanone is added to make 54% of solid content Adjusted to%. As melamine of a crosslinking agent of the obtained coating agent, methyl etherified melamine (Cymel 303, solid content 100% by mass) manufactured by Nippon Cytech Industries, Ltd., and as a pigment (Ti-containing oxide), titanium oxide manufactured by Ishihara Sangyo (R- 930, primary particle size: 250 nm). Table 2 shows various blending ratios. In addition, in Table 2, the mass part of each of a crosslinking agent and a pigment is a mass part (solid content conversion) with respect to 100 mass parts of polyester resin.

<Preparation of test plate>
Plate thickness: A hot-dip galvanized steel sheet of 0.3 mm was cut out to a size of width: 200 mm, length: 300 mm, and used as a test material. The steel plate was subjected to alkaline degreasing according to a conventional method, then washed with water and dried. A primer (V knit # 156 primer) manufactured by Dainippon Paint Co., Ltd. is applied to the surface of the test material subjected to chemical conversion treatment to form a first coating layer using a bar coater so that the dry film thickness is 5 μm, and then the plate The first covering layer was formed by heating so as to reach 210 ° C. in 60 seconds.

  The various coating agents shown in Table 2 are coated on the surface of the first coating layer by a bar coater so that the dry film thickness is 15 μm, and the plate is heated to a temperature of 232 ° C. in 60 seconds to obtain a second coating A layer was formed. In addition, the metal plate in which the same 1st coating layer was formed in all the Examples and comparative examples is used.

The ink 2 shown in Table 3 was discharged as an active energy ray-curable inkjet ink on the second covering layer, and an active energy ray was irradiated to obtain an active energy ray-curable resin layer.
Furthermore, as a protective layer of the active energy ray-curable resin layer, a ratio of 8: 2 in solid ratio of polyester resin (Almatex HMP-15, solid content 50% by mass) manufactured by Mitsui Chemicals, Inc. and melamine resin (Cymel 303) The coating agent mixed in the above was applied by a bar coater, and heating was performed so that the ultimate temperature of the plate reached 232 ° C. in 60 seconds, to prepare a test plate having a clear protective layer with a dry film thickness of 15 μm.

<Evaluation test>
The evaluation test was implemented about the coated board shown in Table 4 as follows.
«Adhesiveness»
Evaluation was carried out in accordance with JIS K 5600-5-6.
After holding the test plate cut into a size of 50 mm × 70 mm in an atmosphere of 23 ° C. and 55% RH for 1 hour, immediately carry out a cross cut of 10 × 10 mass with a grid spacing of 1 mm on the surface of the test plate and tape The peeled area after peeling was observed visually. The evaluation criteria were as follows, and 2 or less was accepted.
0: Peeling area is 0% of cross cut part
1: Peeling area exceeds 1% but not 5% of cross cut part 2: Peeling area exceeds 5% but not 15% of cross cut part 3: Peeling area is cross cut Of more than 15% but not more than 35% 4: Peeling area exceeds 35% of crosscut part but not more than 65% 5: Peeling area exceeds 65% of crosscut

«Processability»
After holding a test plate cut to a size of 50 mm x 70 mm in an atmosphere of 23 ° C and 55% RH for 1 hour, the surface (second coating layer-formed surface) is quickly bent outward with a vise. The presence or absence of a crack on the bending surface after 0 T bending test which does not sandwich the same test plate on the surface was visually observed or observed with a loupe 10 times. The evaluation criteria were as follows, and 1 or less was a pass.
0: There is no crack at all in 10 times loupe observation 1: There is a minute crack in 10 times loupe observation (level not observed visually)
2: Visually cracked 3: Visually cracked

«Ink versatility»
Each ink in the following table (parts by mass) was discharged by an ink jet printer, and the landed ink was irradiated with an active energy ray with a metal halide lamp to obtain an active energy ray cured resin layer having an average film thickness of 10 μm.
Three test plates having a first coating layer, a second coating layer, an active energy ray-curable resin layer obtained from each of the inks 1 to 3 shown in Table 3 and a clear protective layer were prepared, The test described in «Adhesiveness» was conducted and evaluated according to the following criteria.
○: Evaluation standard of adhesion is 2 or less with all 3 types of test plates ×: Other than the above

The following ink has the following properties.
Ink 1
There are few crosslinking components and the cured film is soft. Internal stress is small and easy to adhere.
Ink 2
Intermediate property between Ink 1 and Ink 3
Ink 3
There are many crosslinking components and the cured film is hard. Internal stress is large and hard to adhere.

<Summary of raw materials>
-2-phenoxyethyl acrylate (Kyoeisha Chemical Co., Ltd. monofunctional acrylate monomer)
・ Dipropylene glycol diacrylate (Difunctional ornex bifunctional acrylate monomer)
· Trimethylolpropane triacrylate (3 functional acrylate monomers manufactured by Kyoeisha Chemical Co., Ltd.)
・ BYK-UV3500 (surface conditioner made by BIC-Chemie Japan)
・ 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide (photopolymerization initiator IRGACURE TPO manufactured by BASF Corp.)

本発明は、すべてのインクが良好な付着性を示した。

The invention showed good adhesion of all the inks.

  As is clear from Table 3 above, the present invention has excellent adhesion and ink versatility in the case of metal substrates.

Claims (3)

  A coated metal plate comprising at least a metal plate, a first coating layer, a second coating layer, and an active energy ray curable resin layer in this order, the second coating layer comprising a polyester resin as a main component, the polyester resin A coated metal plate, wherein is an alicyclic hydrocarbon structure.   The coated metal sheet according to claim 1, wherein the second coated layer contains a crosslinked product of a polyester resin and a melamine resin. The coated metal sheet according to claim 1 or 2, wherein the first coating layer contains a crosslinked product of a polyester resin and a melamine resin.