JPH0221936B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a coated metal plate coated with a polyethylene terephthalate biaxially stretched film having a metal thin film layer. BACKGROUND ART Conventionally, a metal plate whose surface has been subjected to a brushing process is molded to produce a molded product having a brushed surface. However, conventional methods have disadvantages in that they tend to scratch the metal surface during the molding process, and the matting process is monotonous, making it impossible to produce molded products with rich designs. Therefore, by painting molded products, scratches can be repaired and designs can be imparted.
However, when painting molded products, it is difficult to create a metallic appearance, and a large number of skilled workers are required, resulting in high costs. Therefore, the method that is considered to be the most economically advantageous is to attach a film to a metal plate. This method uses commonly used inexpensive metal plates such as chromium-treated steel plates, galvanized steel plates, and aluminum plates, without using expensive metal plates that have been subjected to a burnishing process. This method uses adhesive to attach the film. Conventionally, solvent-type adhesives, emulsion-type adhesives, polyolefin-based hot melt adhesives, etc. have been used as adhesives in this method, but they have not yet achieved satisfactory performance and suffer from the following drawbacks: have (1) The degree of elegance is not sufficient and it is not possible to create a calm feeling. It also lacks design. (2) The bending and drawing properties are poor, and the coating layer in the processed area peels off and floats off the metal plate. (3) When punching is performed, the coating layer stretches and protrudes from the punched part of the metal plate, making the punching process difficult. (4) Moisture resistance is poor, and the metal thin film layer disappears from the end surface of the coated metal plate. As a result of studying to improve these drawbacks of conventional products, we found that these drawbacks could be overcome for the first time by a combination of providing a metal thin film layer on a specific polyester film and thermally bonding it to a metal plate via a specific high molecular weight thermoplastic resin. The present invention was achieved by discovering that all of the above can be improved and a coated metal plate with a high design quality can be produced. That is, the coated metal plate of the present invention has a thickness of 10 to
250μ, center line average roughness (hereinafter referred to as Ra value)
0.05μ or more, and the maximum height (hereinafter referred to as Rmax
polyethylene terephthalate biaxially stretched film (hereinafter referred to as polyethylene terephthalate biaxially stretched film) having a rough surface with a roughness of 0.5μ or more
Metal vapor deposition is provided on one side of the PET-BO film (abbreviated as PET-BO film), and this metal thin film layer surface and the metal plate are
~95% by weight and 5~30% by weight of ethylene/vinyl acetate copolymer, which are thermally bonded via a 5~50μ thick adhesive layer. A High molecular weight heat with a melting point of 100 to 230°C and a molecular weight of 10,000 or more, where the diol component is ethylene glycol and butanediol, the dicarboxylic acid component is terephthalic acid and isophthalic acid, and 50 mol% or more of the dicarboxylic acid component is terephthalic acid. Plastic polyester. The PET-BO film used in the present invention has a thickness of
10~250μ, preferably 25~150μ, JIS
The center line average roughness (Ra value) measured with B601 is
It has a rough surface having a roughness of 0.05μ or more, preferably 0.1μ or more, and a maximum height (Rmax value) of 0.5μ or more, preferably 1μ or more. PET-BO film with such a rough surface is (1)
Films made by dispersing and blending fillers such as inorganic fine particles, glass fibers, and glass beads into PET; (2) films whose surface has been roughened by sand matte processing, hair win processing, or chemical treatment; (3) matting agents. coatings, etc. are used. In particular, (1) is preferable from the viewpoint of drawing workability. It is also possible to use PET-BO films with different degrees of roughness on both sides of the film, and with added quality-improving additives such as colorants and ultraviolet absorbers. The metal forming the metal thin film layer is a metal capable of forming a mirror surface, such as aluminum, copper, zinc, gold, silver, platinum, chromium, nickel, tin, or cobalt. Among these, aluminum is preferred from the viewpoint of economy and design. The thickness of the metal thin film layer is 200-2000 Å, preferably 400-1000 Å. The metal thin film layer is made by a known vacuum thin film forming method such as a vapor deposition method, an ion plating method, or a sputtering method. Among these, the vapor deposition method is preferred because it can greatly improve the moisture resistance of the coated metal plate. The high molecular weight thermoplastic polyester of adhesive layer resin A is a high molecular weight material with a molecular weight of 10,000 or more, preferably 15,000 or more, and a melting point of 100 to 230°C, preferably
The temperature is 105-220℃, the diol component is ethylene glycol and butanediol, the dicarboxylic acid component is terephthalic acid and isophthalic acid,
And 50 mol% or more of the dicarboxylic acid component consists of terephthalic acid. In the present invention, 5 to 30% by weight, preferably 10 to 25% by weight of ethylene/vinyl acetate copolymer is blended as another component of the adhesive layer resin. If the amount is too small, the effect of improving moisture resistance will not be significant, while if it is too large, molding processability such as drawing processability and heat resistance will decrease. Furthermore, additives such as inorganic fine particles, adhesion promoters, and heat resistors can be added to the adhesive layer. If the molecular weight of adhesive layer resin A is less than 10,000, punching,
Slightly poor molding processability such as bending and drawing, and moisture resistance. If the melting point of the adhesive layer resin is lower than a predetermined temperature, the coating layer on the end face of the molded product made from the coated metal plate will gradually shrink. Moreover, if the temperature is too high than a predetermined temperature, the moisture resistance will not be sufficient. In the present invention, thermal bonding via an adhesive layer is essential. If the thermal adhesion method is not used, that is, if the adhesive layer resin is dissolved in an organic solvent and applied and bonded, the moisture resistance is poor. The thermal bonding temperature in the present invention is 130 to 240°C, preferably 140 to 230°C. The metal plates used in the present invention include aluminum, iron, copper,
and various alloys, etc., in the form of plates of commonly known metals. The surface of the metal plate may be subjected to various surface treatments such as rust prevention treatment, hardening treatment, adhesion promotion treatment, polishing, etc. in advance. The thickness of the metal plate used is
It is 0.1-5 mm, preferably 0.2-2 mm. The coated metal plate of the present invention can be produced by the following methods, but is not limited to these methods. (1) Create a composite film by melt-extruding and laminating adhesive layer resin on the metal thin film layer surface of PET-BO film. A method in which this composite film and a preheated metal plate are bonded under pressure and heat using a press roll, passed through a heating oven if necessary, and then cooled with water. (2) A method in which a film is made by forming adhesive layer resin in advance, and the film is sandwiched between the metal thin film layer surface of the PET-BO film and a metal plate, and the film is bonded by pressure and heat using a press roll. (3) A method in which the adhesive layer resin is directly melted and extruded between the metal thin film layer surface of the PET-BO film and the metal plate to integrate it, and if necessary, it is passed through a heating oven and then cooled. (4) After melting and extruding the adhesive layer resin onto the metal plate to create a composite of the metal plate/adhesive layer,
Overlap the metal thin film layer side of PET-BO film,
A method of bonding under pressure and heat using a press roll. In the present invention, method (1) is preferred in terms of productivity. In addition, the PET-BO surface layer of the coated metal plate of the present invention
Surface hardening layer, antistatic layer on the surface of the film,
By providing a printed layer such as a colored layer or a pattern by a method such as coating, scratch resistance, dust adhesion prevention, design, etc. can be further improved. The present invention relates to a specific PET-BO having a metal thin film layer.
Since it is a coated metal plate made by thermally bonding a film and a metal plate via a special adhesive layer, it has the following excellent effects. (1) By appropriately selecting the degree of roughness of the PET-BO film, even if the same metal is used and a metal thin film layer is provided, coated metal plates with various tones can be made, resulting in a faded effect. A coated metal plate with a high design quality that takes advantage of this can be obtained. (2) It has excellent forming processability in punching, bending, drawing, etc., and the coating layer does not peel or tear during these processes, and processes with a large degree of deformation can be performed. (3) It has excellent moisture resistance, and the metal thin film layer will not gradually disappear due to moisture. Since the coated metal plate of the present invention has the above-mentioned effects, it can be used for decorative items, fixtures, exterior members for steel products, and building materials such as wall and ceiling materials. The present invention will be specifically described below with reference to Examples. In the present invention, various physical properties were measured by the following methods. (1) Melting point Using a differential calorimeter (DSC), 10 mg of sample,
Melting peak temperature measured at a heating rate of 40°C/min in a nitrogen atmosphere. If the DSC melting point is unclear,
Measured with a penetrometer. In this case, after heat treating the sample at 80°C for 15 hours, the melting point is defined as the temperature at which a 0.5mm diameter pin (load: 5g) penetrates 250μ. (2) Surface roughness PET before metal thinning according to JIS B601
-We measured the Ra value and Rmax value of the BO film. (3) Punching workability A disk with a diameter of 12 cm is punched out from the coated metal plate, the punched surface is observed, and the punching workability is evaluated using the following criteria. ○: Has a clean punching surface. ×: The film peeled off or stretched and protruded from the punched surface. (4) Bending processability The coated metal plate is folded in close contact with the PET-BO film layer side facing outward. A cut reaching the surface of the metal plate is made in the bent part with a knife, the degree of adhesion of the metal coating layer is observed, and the decrease in adhesion due to the bending process is evaluated using the following criteria. 〇: No decrease in adhesion. △: Adhesion is slightly decreased. ×: Adhesion deteriorates and peels off. (5) Drawing workability A disk of coated metal plate punched out for punching workability evaluation was drawn with a die and a punch to a diameter of 6.7 cm and a depth of 6.7 cm.
A cup with a 2.3cm flange is made and its drawability and heat resistance after processing are evaluated using the following criteria. ◎: No defects such as peeling of the film are observed, and no defects are observed even after the processed product is left in an oven at 90°C for 1 hour and taken out. ○: No defects such as peeling of the film are observed, but peeling of the film is observed after leaving the processed product in an oven at 90°C for 1 hour and taking it out. △: Slight peeling is observed on the film at the flange and bottom corners. ×: The film peels off at the flange and bottom corners. (6) Moisture resistance A cross cut with a side length of 10 cm is placed on a 15 cm square coated metal plate and left in boiling water for 1 hour to perform an acceleration test. Observe the disappearance width of the metal thin film layer on the cross-cut surface. ◎: Disappearance is almost 0 mm. 〇: Disappearance width is less than 0.5mm. △: Disappearance width is 0.5 to 1.0 mm. ×: Disappearance width exceeds 1.0 mm. (7) Glossiness 60 degree specular glossiness was measured according to JIS Z8741. Those with a gloss level of 50 or less have a strong eraser effect, and those with a gloss level of 100 or higher have no eraser effect. Example 1 and Comparative Example 1 (1) Aluminum deposited PET-BO film A PET-BO film having a paper-like surface with a thickness of 50μ is produced by biaxially stretching PET containing 20wt% of short glass fibers with a diameter of 10μ. (Film No.1)
I made it. Then aluminum is coated on one side with a thickness of 700Å.
Deposited. For comparison, conventional smooth thickness 8μ
A PET-BO film (film No. 2) was also deposited in the same manner. (2) Melt extrusion laminate of adhesive layer resin: terephthalic acid/isophthalic acid (copolymerization molar ratio: 56/44) as the dicarboxylic acid component and butanediol/ethylene glycol (copolymerization molar ratio: 68/32) as the diol component. Mix 80 wt% of a thermoplastic polyester [melting point 114°C, molecular weight 23000 (vapor pressure method)] with 20 wt% of ethylene/vinyl acetate copolymer (vinyl acetate content 14 wt%, melt index 3.5 g/10 min), and The material was supplied to a 40 mm extrusion laminator having a T-die nozzle with a width of 360 mm, extruded at an extrusion temperature of 170°C, and laminated on the aluminum-deposited surface of the aluminum-deposited PET-BO film. The thickness of the adhesive layer of this composite film is
It was 20μ. (3) Preparation of coated metal plate The adhesive layer surface of the various composite films prepared in (2) above was laid on a galvanized steel plate with a thickness of 0.6 mm, and the adhesive layer surface of the various composite films prepared in (2) above was stacked on a galvanized steel plate with a thickness of 0.6 mm.
A coated metal plate was made in the same manner. (4) Performance evaluation As shown in Table 1, the product of the present invention (Example 1) is a coated metal plate with a Japanese paper-like, subdued white silver color and a high design quality. It had good moldability and moisture resistance. On the other hand, the film using the conventional smooth PET-BO film (Comparative Example 1) had a mirror surface with undulations, no fade effect, and lacked design.
In addition, the bending workability is poor, and when drawing processing is performed,
The PET-BO film broke. It also had poor moisture resistance. Examples 2 and 3 (1) Aluminum evaporated PET-BO film with rough surface with Ra value of 0.1μ and Rmax value of 1.2μ
One and both sides of the PET-BO film (thickness 38μ) are further roughened by sandblasting,
I made films No. 3 (sandblast on one side) and No. 4 (sandblast on both sides). The Ra value and Rmax value of the sandblasted surface are also listed in Table 1. Aluminum was deposited to a thickness of 700 Å on the sandblasted surface of these films. (2) Adhesive layer The melt extrusion laminate of the resin and the preparation of the coated metal plate were carried out in the same manner as in Example 1. (3) Performance evaluation As shown in Table 1, the products of the present invention are vapor-deposited aluminum, but have a deep gray color that is not seen in conventional aluminum vapor-deposited products.
It was a brushed coated metal plate with a silvery white color. In addition, this product had good forming processability such as punching, bending, and drawing, and was also excellent in moisture resistance.

[Table] Comparative Example 2 The following low molecular weight thermoplastic polyester was prepared as the adhesive layer resin. Polyester consisting of terephthalic acid (copolymerization molar ratio: 50/50) as the dicarboxylic acid component and ethylene glycol/neopentyl glycol (copolymerization molar ratio: 55/45) as the diol component [melting point 115°C, molecular weight 3000 (vapor pressure method) )]. This polyester was dissolved in ethyl acetate and coated on one side of a 25μ roughened PET-BO film (Ra value 0.30, Rmax value 3.5) to which 0.7% by weight of silicon dioxide fine particles with an average particle size of 4μ was added. Aluminum was vapor-deposited to a thickness of 500 Å] and coated on the surface of the vapor-deposited layer. The solvent was evaporated at 60°C to produce a half-dried composite film. A chromium-treated steel plate with a thickness of 0.3 mm was coated with the above adhesive, left to dry, and then overlapped with the coating surface of the composite film and bonded with a press roll (linear pressure: 5 kg/cm) to produce a coated metal plate. . The adhesive layer thickness of this product was 4μ. As a result of evaluating this coated metal plate (also listed in Table 1), it was found that the coated metal plate was affected by the surface of the steel plate and had undulations and poor design. Furthermore, when punching was performed, the coating layer on the end face peeled off, and peeling of the coating layer also occurred during bending and drawing. It also had poor moisture resistance. It has been found that when low molecular weight polyester is bonded using a solvent method as described above, a coated metal plate with good design and moldability cannot be obtained. Comparative Examples 3 to 5 Coated metal plates were prepared in the same manner as in Example 1, except that the composition of the adhesive layer resin was changed as shown below.
evaluated. The results are shown in Table 1. (Composition of adhesive layer resin) Comparative example 3: Terephthalic acid/isophthalic acid (copolymerization molar ratio: 56/44) as the dicarboxylic acid component, butanediol/ethylene glycol (copolymerization molar ratio: 68/32) as the diol component. Thermoplastic polyester consisting of [melting point 114°C, molecular weight 23000 (vapor pressure method)] Comparative example 4: Thermoplastic polyester ether
PBT/I-PTMG [terephthalic acid/isophthalic acid (copolymerization molar ratio: 70/30), copolymerization amount of polytetramethylene glycol 50wt%, melting point 155°C, molecular weight approximately 25000 (GPC method)] Comparative example 5: Ethylene・Vinyl acetate copolymer (vinyl acetate content 14wt%, melt index 3.5
g/10 minutes)

Claims (1)

[Claims] 1. A metal vapor-deposited layer is provided on one side of a polyethylene terephthalate biaxially stretched film having a rough surface having a thickness of 10 to 250μ, a center line average roughness of 0.05μ or more, and a maximum height of 0.5μ or more. The surface of the metal vapor deposited layer and the metal plate have a thickness of 5 consisting of 70 to 95% by weight of the following A and 5 to 30% by weight of ethylene/vinyl acetate copolymer.
A coated metal plate that is thermally bonded through a ~50μ adhesive layer. A High molecular weight heat with a melting point of 100 to 230°C and a molecular weight of 10,000 or more, where the diol component is ethylene glycol and butanediol, the dicarboxylic acid component is terephthalic acid and isophthalic acid, and 50 mol% or more of the dicarboxylic acid component is terephthalic acid. Plastic polyester.