JPH0985887A - Fluorine resin film laminated metal sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal sheet having excellent design and weather resistance and ethylene-tetrafluoroethylene copolymer (ETFE) film laminated on a surface-printed metal sheet. SOLUTION: An ETFE film and a printed metal sheet are laminated by using glycidyl(meth)acrylate-ethylene copolymer containing hindered amine optical stabilizer as adhesive.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a fluororesin film-laminated metal plate which is required to have good design and weather resistance.

[0002]

2. Description of the Related Art Ethylene-tetrafluoroethylene copolymer (hereinafter referred to as ETFE) has extremely excellent weather resistance and chemical resistance, and attention is paid to its performance, and a laminate material of ETFE film and stainless steel or aluminum is used as a roof. It is used for materials such as road soundproof walls. However, in these laminated materials, since the adhesive used for laminating the metal and the ETFE film causes photodegradation, a pigment-containing ETFE color film that does not transmit ultraviolet rays is currently used. Therefore, a laminated metal plate excellent in design has not been obtained.

As a method for solving this, Japanese Patent Laid-Open No. 3-1
42237 proposes a structure in which an ETFE film is used as the outermost surface layer, and a printing layer made of a curable fluororesin and an acrylic pressure-sensitive adhesive are laminated on a metal plate, to conceal a fluororesin resin ink having good weather resistance. A method of suppressing the photo-deterioration of the acrylic adhesive of the lower layer by using the force is adopted.

[0004]

However, when immersed in boiling water, the acrylic pressure-sensitive adhesive swells, and there is a problem that the adhesion between the printing layer made of the curable fluororesin and the metal is reduced. The present invention has been made to improve these problems, and provides a fluororesin film-laminated metal sheet that is inexpensive and has excellent designability and weather resistance.

[0005]

The present invention provides a surface layer formed of a transparent ethylene-tetrafluoroethylene copolymer film and a glycidyl (meth) acrylate-ethylene copolymer containing a hindered amine light stabilizer. The present invention relates to a fluororesin film-laminated metal plate having an adhesive layer and a printing layer formed on the surface of the metal plate in this order.

In the present invention, the term "(meth) acrylate" is used to mean both acrylate and methacrylate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A glycidyl (meth) acrylate-ethylene copolymer (hereinafter referred to as a copolymer X) in the present invention means a polymerization unit based on ethylene as a main constitutional unit and adhesion to ETFE. Of 2 to 20% by weight of polymerized units based on glycidyl (meth) acrylate. If the number of polymerized units based on glycidyl (meth) acrylate is too small, the adhesion of the copolymer will be insufficient, and if it is too large, the effect of improving the adhesion will be small, and the amount of unreacted polymerization raw material monomer will be large. When melt-extruding the copolymer, gas is generated or the discharge amount becomes unstable. In addition to these polymerized units, polymerized units based on alkyl (meth) acrylates such as vinyl acetate, methyl acrylate, methyl methacrylate, and ethyl acrylate may be contained in the range of 2 to 10% by weight so as not to reduce the weather resistance. These polymerized units are effective in improving the adhesion with the polyester resin, vinyl acetate resin, epoxy resin, etc. used in the ink of the printing layer.

The copolymer X is less likely to undergo photodegradation than the epoxy resin containing a phenyl group such as a bisphenol A epoxy resin, a polyester resin, and a urethane resin.
Further, in order to suppress photodegradation of the copolymer X, the copolymer X
By adding 0.5 to 5 parts by weight of the hindered amine light stabilizer to 100 parts by weight of the above, the weather resistance of the adhesive made of the copolymer can be dramatically improved.

As a hindered amine light stabilizer, a polycondensate of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine (hereinafter referred to as HALS1) , 1, 2, 3,
Mixed esterified product of 4-butanetetracarboxylic acid and 2,2,6,6-tetramethyl-4-piperidinol and 1-tridecanol (hereinafter referred to as HALS2), bis (2,2,6,6-tetramethyl- 4-piperidine) sebacate and the like are used. The hindered amine light stabilizer has a molecular weight of preferably about 500 to 20,000, more preferably 3,000 or more.

As a method of suppressing the photodegradation of the printed layer on the surface of the metal plate, an ultraviolet absorber having a benzotriazole group or a benzophenone group is further added to 100 parts by weight of the copolymer X in an amount of 0.5. By adding up to 5 parts by weight, 350 nm or less is completely absorbed, and the weather resistance of the printing layer is dramatically improved. The thickness of the adhesive layer is 20 to 100 μm
Is preferred.

Glycidyl (meth) constituting the copolymer X
Epoxy groups in polymerized units based on acrylate are ETF
It greatly contributes to the interfacial adhesion of E. As a general adhesive containing an epoxy group, one having a bisphenol A type epoxy resin as a main constituent unit actually has a large molecular cohesive force of the adhesive itself, excellent interfacial adhesion, and considerably high adhesion. However, since the phenylene group of bisphenol A is largely photo-deteriorated, the weather resistance is not sufficient. Further, a copolymer of glycidyl (meth) acrylate having no phenylene group and a (meth) acrylic monomer has good weather resistance,
The interfacial adhesion of the polymer is excellent, but the molecular cohesion is small and the adhesion is low. On the other hand, the copolymer X having polymerized units based on glycidyl (meth) acrylate and ethylene in the present invention has high molecular cohesive force and excellent interfacial adhesion force, and therefore has high adhesion force and excellent weather resistance. There is.

The copolymer X in the present invention is a hot melt type, and can be directly extrusion-molded on an ETFE film, and then this molded composite film can be thermally laminated on a metal plate provided with a printing layer. In addition, after the adhesive layer is formed in a film shape in advance, the adhesive film can be heat laminated simultaneously with the ETFE film on the metal plate provided with the printing layer.

As the metal plate in the present invention, aluminum, stainless steel (hereinafter abbreviated as SUS), galvanium metal plate, galvanized metal plate, steel plate or the like is used.

The printing layer is silk printing, screen printing,
It can be formed by a general metal printing means such as gravure printing. As the resin that makes up the ink, fluororesin,
Acrylic resins, polyester resins, alkyd melamine resins, epoxy resins, urethane resins can be used. Among these resins, alkyd melamine resins and polyester resins, which have high adhesion to the adhesive layer, are preferable.

The printing layer can also be formed by forming it on a synthetic resin film having adhesiveness and laminating this printing film on a metal plate or the like.

As the transparent ETFE film in the present invention, a film having a total light transmittance at 400 nm of 60% or more is used. When the transmittance is lower than this, the printed pattern of the lower layer becomes unclear and the design of the laminated metal plate becomes insufficient. Further, silica, mica and the like can be added to the ETFE film in order to improve the surface hardness of the ETFE film within the range of maintaining the total light transmittance of 60%. It is also possible to add an ultraviolet absorber for the purpose of further improving the weather resistance. The thickness of the ETFE film is preferably 20 to 100 μm from the viewpoint of scratch resistance.

In the present invention, the surface of the ETFE film is preferably surface-treated in order to ensure sufficient adhesion with the adhesive layer. Examples of the surface treatment method include treatment methods such as corona discharge treatment and excimer laser treatment.

Examples will be described below.

[0019]

Examples [Example 1] Copolymer A in which polymer units based on ethylene / glycidyl methacrylate are 94/6 (weight ratio)
Was synthesized. The melting point of copolymer A is 105 ° C.
Melt flow rate (hereinafter referred to as MFR) at 190 ° C. measured according to SK-7210 was 3.2 g.
/ 10 minutes.

With respect to 100 parts by weight of the copolymer A, 2 parts by weight of a benzophenone type ultraviolet absorber (trade name; ASL-23, manufactured by Shonan Chemical Co., Ltd.) and a light stabilizer HALS1 (trade name: T) are used.
Inuvin 622LD, manufactured by Ciba Geigy), was added with 1 part by weight of an adhesive, and the thickness was 50 μm after corona discharge treatment.
A 50 μm thick film was extruded onto an ETFE film (trade name; Aflex 50N, manufactured by Asahi Glass Co., Ltd.) at a processing temperature of 200 ° C. to prepare a composite film A having a thickness of 100 μm. The total light transmittance of the ETFE film at 400 nm is 85%.

Next, a white polyester resin ink was printed on the entire surface of the SUS430 plate, and a blue polyester resin ink was printed in a stripe pattern on the printed surface. The printed SUS430 plate was preheated to 220 ° C., and then the composite film A was heat-laminated by passing through a hot roll held at 120 ° C. to obtain a fluororesin film-laminated metal plate.

The ETFE film and the adhesive layer were so closely attached that they could not be separated, and the peeling interface was between the adhesive layer and the printing layer. The adhesive force between the adhesive layer and the printing layer is 1.7 kg / cm.
Therefore, the adhesive strength was practically no problem. After this test piece was immersed in boiling water for 10 hours, the adhesion was measured again, and as a result, there was no decrease in the adhesion. Further, the test piece was put in a sunshine weatherometer for 5000 hours and then the adhesion was measured. As a result, the peeling interface was the adhesive layer and the printing layer as before the exposure. The adhesive force between the adhesive layer and the printing layer was 1.6 kg / cm, which was a strong adhesive force with no practical problems. In addition, the color difference ΔE of the test piece after exposure
Was a very small change with 1.2 parts by weight in white and 3.8 parts by weight in blue.

Example 2 A polymer unit based on ethylene / glycidyl methacrylate / vinyl acetate was 83/12 /
A copolymer B consisting of 5 (weight ratio) was synthesized. The melting point of copolymer B was 95 ° C., and the MFR at 190 ° C. was 6.9 g / 10 minutes.

With respect to 100 parts by weight of the copolymer B, a benzotriazole-based ultraviolet absorber (trade name; Biosorb-
550, manufactured by Kyodo Pharmaceutical Co., Ltd.), 2 parts by weight, light stabilizer HALS1
An adhesive containing 3 parts by weight of (trade name: Tinuvin 622LD, manufactured by Ciba-Geigy) was processed at 200 ° C. on a 25 μm-thick ETFE film (trade name: Aflex 25HK, manufactured by Asahi Glass) in the shape of a mat, which was subjected to corona discharge treatment. A 30 μm thick film was extruded at a temperature to prepare a 55 μm thick composite film B. The total light transmittance of this ETFE film at 400 nm is 78%. Next, a white alkyd melamine resin ink was printed on the entire surface of the SUS430 plate, and a blue alkyd melamine resin ink was printed in a stripe pattern on the printed surface. The printed SUS430 plate was preheated to 220 ° C., and then the composite film B was heat-laminated by passing it through a hot roll held at 120 ° C. to obtain a fluororesin film-laminated metal plate.

The ETFE film and the adhesive layer were so closely attached that they could not be separated, and the separation interface was the adhesive layer and the printing layer. The adhesive force between the adhesive layer and the printing layer was 1.6 kg / cm, which was a strong adhesive force with no practical problems. After soaking this test piece in boiling water for 10 hours, the adhesion was measured again, and there was no decrease in the adhesion. The test piece was placed in a sunshine weatherometer for 5,000 hours and the adhesion was measured. As a result, the peeling interface was different from that before exposure and was the adhesive layer and the ETFE film. The adhesive strength between the adhesive layer and the ETFE film was 1.3 kg / cm, which was a strong adhesive strength with no practical problems. The color difference ΔE of the test piece after exposure was 1.
The change was 0, and the blue part was 2.5, which was an extremely small change.

[Example 3] Example 2 was carried out with respect to the copolymer B.
2 parts by weight of the same benzotriazole-based UV absorber as described above, light stabilizer HALS2 (trade name; ADEKA STAB LA
-67, manufactured by Asahi Denka Co., Ltd.), a 35 μm thick ETFE film (trade name; Aflex 35GN) containing corona discharge treated adhesive containing 2% of flattened mica for improving surface hardness. Asahi Glass) 200 ℃
A composite film C having a thickness of 65 μm was prepared by extruding a film having a thickness of 30 μm at the processing temperature of. In addition,
The total light transmittance at 400 nm of this ETFE film was 62%.

Then, a white polyester resin ink was printed on the entire surface of the SUS430 plate, and a blue polyester resin ink was printed in a stripe pattern on the printed surface. The printed SUS430 plate was preheated to 220 ° C., and then the composite film C was heat-laminated by passing through a hot roll held at 120 ° C. to obtain a fluororesin film-laminated metal plate.

The ETFE film and the adhesive layer were so closely attached that they could not be peeled off, and the peeling interface was between the adhesive layer and the printed layer. Adhesive force between adhesive layer and printing layer is 1.4kg / cm
Therefore, it had a strong adhesion without any problem in practical use. After soaking this test piece in boiling water for 10 hours, the adhesion was measured again, and there was no decrease in the adhesion. Further, the test piece was put in a sunshine weatherometer for 5000 hours and then the adhesion was measured. As a result, the peeling interface was the adhesive layer and the printing layer as before the exposure. The adhesive force between the adhesive layer and the printing layer was 1.1 kg / cm, which was a strong adhesive force with no practical problems. In addition, the color difference ΔE of the test piece after the exposure was a very small change of 1.0 in the white part and 3.1 in the blue part.

Comparative Example 1 A fluororesin film-laminated metal plate was prepared in the same manner as in Example 1 except that the hindered amine light stabilizer was not added to the copolymer A. In the normal state adhesion test and the 10-hour boiling water test, the values were the same as in Example 1. However, as a result of measuring the adhesive force after putting it in the sunshine weatherometer for 5000 hours, the peeling interface was ETFE film and the adhesive layer,
It had fallen to g / cm. In addition, the color difference ΔE of the test piece after exposure was 2.0 in the white part by weight and 5.0 in the blue part by weight, showing very little discoloration.

Comparative Example 2 The thickness used in Example 1 is 50 μm.
m ETFE film and a striped printed metal plate prepared in the same manner as in Example 1 with acrylic adhesive (trade name: S
100 parts by weight of Kdyne 1222, manufactured by Soken Chemical Co., Ltd. and 2 parts by weight of an isocyanate curing agent (trade name; L-45, manufactured by Soken Chemical Co., Ltd.) were used for lamination. The pressure-sensitive adhesive had a thickness of 40 μm. The ETFE film and the pressure-sensitive adhesive layer were in close contact with each other so that they could not be peeled off, and the peeling interface was the pressure-sensitive adhesive layer and the printed layer. Adhesive force between adhesive and printed layer is 1.2kg / c
m It had a strong adhesion without any problem in practical use. However, after immersing this test piece in boiling water for 10 hours and then measuring the adhesive force again, the adhesive force between the adhesive and the printed layer was
It was 0.3 kg / cm, and the decrease in adhesion was extremely large.

Comparative Example 3 50 μmE used in Example 1
The TFE film and the striped printed metal plate prepared in Example 1 are coated with a polyester adhesive (trade name: Byron 5
0AS, manufactured by Toyobo), 5 parts by weight of an isocyanate curing agent (trade name; Coronate L, manufactured by Nippon Polyurethane), and 4 parts by weight of the ultraviolet absorber used in Example 1 were laminated. The thickness of the adhesive layer was 20 μm.

The adhesive layer and the printed layer were in very close contact with each other, and the peeling interface was the interface between the adhesive layer and the ETFE film. Adhesion between the adhesive layer and ETFE film is 1.0k
It was g / cm. The test piece was dipped in boiling water for 10 hours, and the adhesion was measured again. As a result, the adhesion between the adhesive layer and the ETFE film was 0.9 kg / cm. In addition, 500 in the sunshine weatherometer
As a result of measuring the adhesive force after putting it in for 0 hour, the peeling interface is E
It was the TFE film and the adhesive layer, and it was lowered to 0.1 kg / cm. The color difference ΔE of the test piece after exposure is
The white part was 3.5, and the blue part was 5.0, showing little discoloration.

[0033]

[Effects of the Invention] Surface-printed metal plate and transparent ETFE
By interposing the film with a glycidyl (meth) acrylate ethylene-based copolymer containing a hindered amine-based light stabilizer as an adhesive, a fluororesin film-laminated metal plate that is sufficiently resistant to outdoor exposure and has a design property can be obtained.

Claims (2)

[Claims] 1. A surface layer formed of a transparent ethylene-tetrafluoroethylene copolymer film, an adhesive layer made of a glycidyl (meth) acrylate-ethylene copolymer containing a hindered amine light stabilizer, and printing. A fluororesin film-laminated metal plate, wherein layers are formed in this order on the surface of the metal plate. 2. The fluororesin film-laminated metal plate according to claim 1, wherein the glycidyl (meth) acrylate-ethylene copolymer contains 2 to 20% by weight of a polymer unit based on glycidyl (meth) acrylate.