JP3084617B2 - Resin coated metal plate for UV curing coating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated metal sheet suitable for one-sided coating and printing of a UV-curable paint such as a container material and a steel furniture material. By pre-coating an aqueous urethane paint as a coating, the adhesion of the UV-cured paint, especially the adhesion of the processed part is improved, and further, by adding a white pigment to the aqueous urethane paint, BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin-coated metal plate that enables cost reduction and environmental measures for harmful gas emission by omitting a conventional solvent-type base coating and a UV-curable white base coating.

[0002]

2. Description of the Related Art In recent years, ultraviolet curable paints are frequently used for coating wooden furniture surfaces and papers because of the advantages of low organic solvent emission and compact drying equipment. When an ultraviolet curable paint is directly applied to a metal plate such as a steel plate or an aluminum plate having a metal plating film or a chemical conversion coating film on the outermost layer, the adhesion may be a problem, and in many cases, a solvent is used. A method in which a base coat is applied to the base or a method using a special surface coating structure or a special oil has been proposed as shown in Japanese Patent No. 1462857.

[0003]

As described above, there is a problem that the ultraviolet curable paint has poor adhesion to the surface of the metal plate. At present, to solve this problem, a base coat is applied or a special paint is applied. Processing is required, and there are problems of both environmental measures and cost reduction. Further, when printability is emphasized, it is a general coating method to apply a white UV-curable paint as a printing base to enhance the clarity of printing, which increases the cost.

According to the present invention, the adhesion of an ultraviolet-curable paint is improved by previously applying a water-based urethane coating to the base of the ultraviolet-cured paint surface of a metal plate, and the addition of a white pigment also eliminates the use of an ultraviolet-curable white paint. Is made possible.

[0005]

That is, the gist of the present invention is as follows. (1) Applying an ultraviolet-curable paint to a metal plate having a metal plating film or a chemical conversion coating film on the outermost layers on both surfaces. A resin-coated metal plate for ultraviolet-curing coating characterized by having an aqueous urethane resin film on one surface. .

(2) The resin-coated metal plate for ultraviolet-curing coating according to the above (1), further comprising a thermosetting resin film on the other surface. (3) The resin-coated metal plate for ultraviolet-curing coating according to the above (1), further comprising a thermoplastic resin film on the other surface. (4) The resin-coated metal plate for ultraviolet curing coating according to (3), wherein the melting point of the thermoplastic resin is 180 ° C. or less.

(5) The resin-coated metal for ultraviolet-curing coating according to any one of (1) to (4), wherein the aqueous urethane resin film contains 5 to 20% by weight of a white pigment. Board. Hereinafter, the present invention will be described in detail. The present invention provides an undercoat of an aqueous urethane-based resin for improving the adhesion of an ultraviolet-curing paint on the outer surface coating / printing side, and depending on the application on the opposite side, metal plating, an aqueous thermosetting resin, a thermoplastic resin in advance. It is characterized by being a coated metal plate.

The metal plate used in the present invention includes aluminum, iron, and alloys mainly composed of these.
The present invention is not particularly limited thereto, but applies to all metal materials generally used as container materials. These metal plates may be appropriately added to Sn, Ni, Cr, Z in order to impart corrosion resistance and adhesion according to the application.
A chemical treatment such as plating of a metal such as n or Al and alloys thereof and chromium or phosphorous hydrated oxide coating is performed. Typical examples of these coating methods include general electroplating, hot-dip plating, chemical plating, and simple application. Further, the thickness of these metal plates varies depending on the size of the container, the application, etc., but is generally 0.10 mm to 1.5 mm.
Are used.

As a matter of course, the undercoat on the surface of the surface-treated metal plate to which the ultraviolet-curable paint is applied must be an environmentally compatible water-based resin. For improvement, it is required that the basic component of the resin be a urethane resin. further,
In order to omit the UV-curable white paint, it is required to contain 5 to 20% by weight of a white pigment such as titanium oxide and silica. With the same water-based epoxy resin or ester resin, satisfactory results could not be obtained with respect to the adhesion to the upper UV-curable paint. The coating thickness of the base aqueous urethane resin is determined by the uniformity of coating and the cost. The lower limit is about 2 μm, and the upper limit varies depending on the coating method, but generally about 50 μm is the limit. Among titanium oxide-based white pigments, anatase-based white pigments are generally used because they have high whiteness and are inexpensive. As for the content, if the lower limit is less than 5%, white unevenness or the like occurs, the whiteness is 60 or less in L value, and a satisfactory level of sharpness after printing cannot be obtained. Exceeds 20%, the effect on the L value and the sharpness is lost, and the cost increases.

[0010] The surface of the surface-treated metal plate to which the ultraviolet curable paint is not applied can be used as it is in the state of metal plating depending on the application. Of a thermosetting resin or a thermoplastic resin. As an aqueous thermosetting resin,
Various urethanes, epoxies, and esters may be mentioned, but are not particularly limited, and are determined by required quality and cost. The thickness of the aqueous thermosetting resin film is 0.
A range of 1 to 50 μm is common. Further, when further corrosion resistance is required, a thermoplastic resin is coated. As a coating method, a general method such as a film lamination method in which a film is bonded by heating or a method in which a resin is coated with T
There is an extrusion lamination method for directly coating by melt extrusion with a die. As the thermoplastic resin coating in this case, polyethylene terephthalate, polybutylene terephthalate, polyamide or the like having a melting point of 20
Not only resins exceeding 0 ° C., but also polypropylene, polyethylene, and polyolefin resins as low melting point (180 ° C. or less) resins having low resin cost and excellent corrosion resistance can be used. The thickness of the thermoplastic resin varies depending on the type and use of the final product, but generally ranges from 5 to 5.
A range of 200 μm, especially 20 to 100 μm is preferred.
In this case, the lower limit is determined by corrosion resistance, and the upper limit is determined by workability and cost.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described based on embodiments. Example 1-1-1 A low-carbon cold-rolled steel sheet cold-rolled and annealed by an ordinary method is degreased and pickled by an ordinary method, and then subjected to ordinary Sn plating (Sn = 2.8 g / m ² ), a normal reflow treatment is performed to form a Sn—Fe alloy layer, and a chromate treatment (total chromium amount is 20)
mg / m ² ) on one side of a tin material, an aqueous urethane resin (manufactured by Sanyo Kasei Kogyo Co., Ltd., trade name: Ucoat 4240) is coated with a 5 μm undercoat, and an ultraviolet curable ink (5 μm) is further coated thereon. A UV-curable clear coating (15 μm) was applied and subjected to various evaluation tests.

[Example 1-1-2] Cold pressure was obtained by a usual method.
On one side of the rolled and annealed aluminum plate
After degreasing and chromating in the usual way (for all
20mg / m as rom amount ^Two) Aqueous urethane on top
Resin (manufactured by Sanyo Chemical Industry Co., Ltd., trade name Ucoat 4)
240) is coated with a 5 μm undercoating, and then UV hardened
Type ink (5μm) and UV curable clear coating (1
5 μm) and subjected to various evaluation tests.

Example 1-2 In Example 1-1-1, an aqueous urethane resin was coated on both sides of a tin material at 5 μm, and on one side thereof, an ultraviolet curable ink (5 μm) and an ultraviolet curable clear were applied. Coating (15 μm) was applied and subjected to various evaluation tests. [Example 1-3] In Example 1-1-1, an adhesive layer (manufactured by Mitsui Petrochemical Co., Ltd., trade name: ADMER QE060) was formed on the surface side not coated with the aqueous urethane resin and the ultraviolet curable paint. ) Via 100μ
m, and subjected to various evaluation tests.

[Example 1-4] In Example 1-1-1
And instead of tin material, Cr plating is 100mg / m
^TwoIt was subjected to various evaluation tests as the applied tin-free material. [Example 1-5] The same procedure as in Example 1-1-1, except that the tin material was used.
Instead of Ni plating, 1.0g / m ^TwoWith the applied material
And subjected to various evaluation tests.

[Example 1-6] In Example 1-4,
Aqueous urethane resin 5μm on both sides of tin-free material
It was coated, and one side thereof was coated with an ultraviolet-curable ink (5 μm) and an ultraviolet-curable clear coating (15 μm), and subjected to various evaluation tests. [Example 1-7] In Example 1-4, an adhesive layer (manufactured by Mitsui Petrochemical Industry Co., Ltd., trade name: ADMER QE060) was applied to the surface side not coated with the aqueous urethane resin and the ultraviolet curable paint. Through a 100 μm laminate and subjected to various evaluation tests.

[Embodiment 1-8] In Embodiment 1-3,
Adhesive layer made of polyethylene resin instead of polypropylene resin (trade name ADMER XE, manufactured by Mitsui Petrochemical Industries, Ltd.)
070), and was subjected to various evaluation tests. [Example 1-9] In Example 1-7, instead of polypropylene resin, a polyethylene resin was laminated and coated with a 70 μm layer via an adhesive layer (trade name: ADMER XE070, manufactured by Mitsui Petrochemical Industries, Ltd.), and subjected to various evaluation tests. Provided.

[Example 1-10] In Example 1-3, a polyethylene terephthalate resin was coated in a thickness of 30 µm in place of the polypropylene resin, and subjected to various evaluation tests. [Example 1-11] In Example 1-7, a polyethylene terephthalate resin was coated in a thickness of 30 µm in place of the polypropylene resin, and subjected to various evaluation tests.

[Comparative Example 1-1] In Example 1-1-1, an aqueous urethane resin was omitted, and an ultraviolet curable ink and a paint were applied directly on a tin material. Other items are the same as in Example 1-1-1. [Comparative Example 1-2] The same as Example 1-4 except that the aqueous urethane resin was omitted, and the ultraviolet curable ink and paint were applied directly on the tin-free steel material. Other items are the same as those of the embodiment 1-4.

[Comparative Example 1-3] In Example 1-4,
What applied aqueous ester resin instead of aqueous urethane resin. Other items are the same as those of the embodiment 1-4. [Comparative Example 1-4] The same as Example 1-4, except that an aqueous epoxy resin was applied instead of the aqueous urethane resin.
Other items are the same as those of the embodiment 1-4.

[Comparative Example 1-5] In Example 1-3,
Instead of UV-curable coating, it is coated with current solvent-based ink and paint. Other items are the same as those of the embodiment 1-3. [Comparative Example 1-6] The same method as in Example 1-9, except that the current solvent-based ink and paint were applied instead of the ultraviolet-curable coating. Other items are the same as those of the embodiment 1-3.

Example 2-1-1 A low-carbon cold-rolled steel sheet cold-rolled and annealed by an ordinary method is degreased and pickled by an ordinary method, and then subjected to ordinary Sn plating (Sn = 2). .8g
/ M ² ) and normal reflow processing to perform Sn-F
An e-alloy layer was formed, and one side of a tin material further subjected to a chromate treatment (total chromium amount: 20 mg / m ² ) was coated with an aqueous white urethane resin (trade name: Ucoat 4240 + titanium oxide 15 by Sanyo Chemical Industry Co., Ltd.) %) Was coated with a 5 μm undercoat, and an ultraviolet-curable ink (5 μm) and an ultraviolet-curable clear coating (15 μm) were further applied thereon, and subjected to various evaluation tests.

[Example 2-1-2] Cold pressure by a usual method
On one side of the rolled and annealed aluminum plate
After degreasing and chromating in the usual way (for all
20mg / m as rom amount ^Two) And aqueous white
Rethane resin (manufactured by Sanyo Chemical Industry Co., Ltd., trade name: Yuko)
4240 + titanium oxide 15%)
In addition, UV curable ink (5 μm) and UV light
Hardening clear coating (15μm) and various evaluation tests
Was served.

[Example 2-2] In Example 2-1-1, an aqueous white urethane resin was applied to both surfaces of a tin material by 5 μm.
It was coated, and one side thereof was coated with an ultraviolet-curable ink (5 μm) and an ultraviolet-curable clear coating (15 μm), and subjected to various evaluation tests. [Example 2-3] In Example 2-1-1, before applying the ultraviolet-curable coating material, a polypropylene resin was applied to the opposite surface via an adhesive layer (trade name: ADMER QE060, manufactured by Mitsui Petrochemical Industries, Ltd.). The laminate coated with 100 μm was subjected to various evaluation tests.

[Example 2-4] In Example 2-1-1, 100 mg / m 2 of Cr plating was used instead of the tin plate.
^It was subjected to various evaluation tests as ^two tin-free materials. In Example 2-5] Example 2-1-1 instead of the tin material, and subjected to various evaluation tests Ni plating as a material which has been subjected 1 g / m ^2.

[Example 2-6] In Example 2-4,
5μ of aqueous white urethane resin on both sides of tin-free material
m painted, UV curable ink (5μm) on one side
And a UV-curable clear coating (15 μm) and subjected to various evaluation tests. [Example 2-7] In Example 2-4, before applying the ultraviolet-curable paint, a polypropylene resin was applied to the opposite surface side with an adhesive layer (trade name Admer Q, manufactured by Mitsui Petrochemical Industries, Ltd.)
E060) and subjected to various evaluation tests.

[Embodiment 2-8] In Embodiment 2-3,
Adhesive layer made of polyethylene resin instead of polypropylene resin (trade name ADMER XE, manufactured by Mitsui Petrochemical Industries, Ltd.)
070), and was subjected to various evaluation tests. [Example 2-9] In Example 2-7, instead of polypropylene resin, a polyethylene resin was laminated and coated with 70 μm via an adhesive layer (trade name: ADMER XE070, manufactured by Mitsui Petrochemical Co., Ltd.), and subjected to various evaluation tests. Provided.

Example 2-10 In Example 2-3, a polyethylene terephthalate resin was coated in a thickness of 30 μm in place of the polypropylene resin, and subjected to various evaluation tests. [Example 2-11] In Example 2-7, a polyethylene terephthalate resin was laminated and coated in a thickness of 30 µm in place of the polypropylene resin, and subjected to various evaluation tests.

[Comparative Example 2-1] In the same manner as in Example 2-1-1, except that the aqueous white urethane resin was omitted, and an ultraviolet curable ink and a paint were applied directly on the tin material. Other items are the same as those in Example 2-1-1. [Comparative Example 2-1-1] In Example 2-1-1, the amount of titanium oxide in the aqueous white urethane resin was set to 4%, and an ultraviolet curable ink and a paint were applied thereon. Other items are the same as those in Example 2-1-1.

Comparative Example 2-2 In Example 2-4,
UV-curable ink and paint applied directly on tin-free steel, omitting the aqueous white urethane resin. Other items are the same as those of the embodiment 2-4. [Comparative Example 2-3] An example in which an aqueous white ester-based resin (content of titanium oxide = 15%) was applied instead of the aqueous white urethane resin in Example 2-4. Other items are the same as those of the embodiment 2-4.

Comparative Example 2-4 In Example 2-4,
An aqueous white epoxy resin (content of titanium oxide = 15%) applied instead of the white urethane resin. Other items are the same as those of the embodiment 2-4. [Comparative Example 2-5] The same method as in Example 2-3 except that the current solvent-based ink and paint were applied instead of the ultraviolet-curable coating. Other items are the same as those of the embodiment 2-3.

[Comparative Example 2-6] In Example 2-9,
Instead of UV-curable coating, it is coated with current solvent-based ink and paint. Other items are the same as those of the embodiment 2-3. Examples of the present invention and comparative examples described above are shown below in (a) to (a).
It was subjected to the evaluation test of (e) and the characteristics were compared.

(A) Evaluation of Adhesion of UV-Curable Coating-1 Evaluation of adhesion of UV-curable coating was performed by bending 1t so that the surface of the UV-curable coating was on the inside, and the surface near the top of the bend. Observe the appearance with a magnifying glass.
A sample where partial peeling was observed was rated as Δ, and a sample where complete peeling was performed was rated X. (B) Evaluation of adhesion of UV-curable coating-2 Evaluation of adhesion of UV-curable coating-2 was carried out from the inner side with a Dupont impact test (1/2 inch diameter, 500 g) so that the surface of the UV-curable coating was on the outside. , 30 cm), and the surface appearance near the impact apex was observed with a magnifying glass. A sample without peeling was rated as ○, a sample with partial peeling was rated as Δ, and a sample with complete peeling was rated as ×.

(C) Evaluation of Corrosion Resistance on the Inner Side The Erichsen extrusion process was performed 4 mm so that the inner surface of the can became convex, (1) methanol, (2) 5% saline, and (3) strong alkali (alkylbenzene sulfone). (A 25% solution of acid soda) for 1 month, and the rust was evaluated. The evaluation was ◎ for no rust, ○ for discolored, 微小 for slight rust, and × for completely rusted.
And

(D) Evaluation of printability It was observed and evaluated whether or not the ink on the outer surface and the resin on the inner surface changed at the time of coating. X. (E) Evaluation of print clarity The coated surface side of the base white urethane resin was measured with a color meter.
Measure the degree of whiteness as a value, further apply an ultraviolet curable ink paint, and visually evaluate the degree of sharpness ○, △, ×
Was evaluated.

The above test results are shown in Tables 1 and 2 (continuation-1 in Table 1), Table 3 (continuation-2 in Table 1), Tables 4 and 5 (continuation-1 in Table 4), and Table 6 (continuation-1 in Table 4). The results are summarized in Table 4-2).

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

[0042]

As described above, the present invention improves the adhesiveness of an ultraviolet curable paint, particularly the adhesion of a processed part, by pre-coating an aqueous urethane paint as a base coat of the ultraviolet curable paint. By further adding a white pigment to the aqueous urethane-based paint, the conventional solvent-based undercoat, and further, a UV-curable white undercoat is omitted,
It enables cost reduction and measures to reduce harmful gas emissions.

Claims (5)

(57) [Claims] 1. A resin coating for ultraviolet-curing coating, wherein an aqueous urethane-based resin coating is applied to one surface of a metal plate having a metal plating film or a chemical conversion coating film on the outermost layers on both surfaces. Metal plate. 2. The resin-coated metal plate for ultraviolet curing coating according to claim 1, further comprising a thermosetting resin film on the other surface. 3. The resin-coated metal plate for ultraviolet-curing coating according to claim 1, further comprising a thermoplastic resin film on the other surface. 4. The resin-coated metal plate for ultraviolet curing coating according to claim 3, wherein the melting point of the thermoplastic resin is 180 ° C. or less. 5. The aqueous urethane-based resin film contains 5 to 20% by weight of a white pigment.
The resin-coated metal plate for ultraviolet curing coating according to any one of the above.