JPH09175098A - Manufacture of patterned metal sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform stable patterning with high efficiency to one or both surfaces of a metal sheet. SOLUTION: In this manufacture of a patterned metal sheet P, a patterning layer 6 is formed as a transfer layer at least on a base material sheet 3 with a transfer sheet N having a release property, and on one or both surfaces of a metal sheet B with a resin receiving layer 2 formed at least on its one surface, an adhesive layer 5 Is superimposed in a faced manner, then, it is passed through a metal roll heated by an induction heating method and a rubber elastic roll adjacent thereto to be subjected to a heating and pressing process for bonding the transfer layer and resin layer, and then the base sheet 3 is released and removed from the transfer layer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing various painted metal sheets. More specifically, the present invention relates to a particularly excellent manufacturing method for manufacturing a painting blind.

[0002]

2. Description of the Related Art Conventionally, various kinds of metal sheets having a decorative surface have been manufactured. A typical example is a metal blind. Since such a metal sheet is poor in printability, most of the metal blinds have conventionally been of a single color design, and even if the front and back sides are colored solid, they are often inferior in design. Also, as the decoration method, since a coating material containing an organic solvent is used, there is an environmental problem in the workplace due to volatilization of the solvent. Further, during coating, it was necessary to make fine adjustments to keep the finished state of the product constant by blending the paint, dilution, coating conditions, and the like.

As a method of improving these points and providing a decorative layer having a clear pattern on the surface of a metal blind, a decorative layer is once formed on a releasable substrate sheet having printability, and then the decorative layer is formed. A so-called transfer painting method has been attempted, in which is transferred to the surface of a metal blind. FIG. 8 shows Japanese Patent Laid-Open No. 3-235893.
FIG. 3 is a principle diagram of a method of applying a transfer image onto a metal sheet according to the conventional technique disclosed in Japanese Patent Publication No. Recently, heated silicon rubber roll SGR (usually the surface of the iron core is coated with silicon rubber) is used for decoration by transfer of pressure from each other, resulting in environmental pollution by the organic solvent and finish of decoration. Although the problem of fine adjustment to the above has been solved, this method requires the heat required for transfer to be supplied to the silicon rubber roll SGR by the external heater H and the thermal conductivity K of the silicon rubber is small. However, there is a problem in that the transfer layer is inferior in adhesiveness, and if the transfer is performed under the conditions for obtaining sufficient adhesive strength, high-speed production cannot be performed. In general, when a hot body and a cold body come into contact, heat moves from the hot body to the cold body according to the second law of thermodynamics, that is, the law of increasing entropy in a closed system, and the hot body cools while the cold body cools. Heats up. Then, the temperature gradient between the two bodies becomes gentle accordingly.
FIG. 5: is explanatory drawing regarding the movement of the heat in the said system. When the heating roll (high temperature object 1) has a small thermal conductivity K such as that of silicone rubber and the metal sheet (low temperature object 2) which is the object to be heated has a large K, the metal sheet rises in the thermal equilibrium state. The temperature amount ΔT is small, and the depth (thickness) Δx of the temperature rising region is also localized and narrow near the surface in contact with the heating roll. As a result of detailed analysis of the phenomenon, the following was found. That is, since the heating roll has a low thermal conductivity, the amount of heat (heat flow) input from the heating roll to the metal sheet per unit time is small, and even a small amount of the heat once enters the metal sheet, the high thermal conductivity of the metal is high. Therefore, there are few substances that diffuse and dissipate quickly and contribute to the temperature rise. This can be confirmed more precisely by applying the initial condition and the boundary condition as shown in FIG. 5 to the heat conduction equation (Equation 1) to solve. Here, C is the specific heat of the object, and ρ is the density.

[0004]

[Equation 1]

As described above, in addition to the poor heating efficiency and transfer efficiency, the silicon rubber roll SGR is damaged by high-temperature heating, so that it is necessary to perform maintenance such as re-sticking the rubber periodically.

As another method of the prior art, there is a method of transferring by pressing the metal rolls MR having good thermal conductivity. In heating the metal roll MR, the inside of the metal roll MR is made hollow, and hot water, heated steam, etc. are circulated therein, whereby a heat flow is input to the structure of the metal roll at a high speed, and the heat flow is spread throughout and passes through. And by going out,
The purpose was to raise the temperature of the metal sheet B of the object to be heated with good uniformity and in a short time. However, when only the rigid metal roll MR is used, the pressure may fluctuate due to a slight displacement or fluctuation of the roll position during the transfer, or a variation in the thickness of the metal sheet or the transfer sheet N, resulting in non-uniform adhesion. Further, it takes a considerable time for the surface temperature of the metal roll to reach a thermal equilibrium state. In addition, hot water and heated steam may cause rust on the metal roll. Moreover, the expected heating efficiency cannot be obtained. The above method, that is, the heating roll (high temperature object 1) is made of metal having high thermal conductivity, and
When the heat transfer rate from the metal roll to the metal sheet was increased and the transfer of heat in the transfer in which the impression cylinder was made of metal was also analyzed, the following was unexpectedly found. FIG. 6 is an explanatory diagram of heat transfer relating to a transfer method by pressing of metal rolls having good thermal conductivity. Compared to the above-mentioned method of heating the silicon rubber roll from the outside, the method of transferring by pressurizing the metal rolls having good thermal conductivity surely increases both the temperature rise amount ΔT and the depth (thickness) of the temperature rise region. (Improved), but still insufficient. And, in principle, it turned out that this method cannot be expected to achieve a revolutionary improvement. That is, a large amount of heat is input per unit time from a high thermal conductivity metal roll into a high thermal conductivity metal sheet (object to be heated). Although it spreads over the entire sheet, since the impression cylinder is also made of metal, heat is immediately discharged through the impression cylinder. Therefore, the temperature rise is limited to the vicinity of the surface in contact with the heating roll. However, the degree is only relaxed as compared with the external heating method of the silicon rubber roll described above.

[0007]

Provided is a technique capable of highly efficiently performing decoration and painting by stable heat transfer on one side or both sides of a metal sheet.

[0008]

A manufacturing method capable of solving the problems is as follows. That is, a transfer sheet in which at least a decorative layer is provided as a transfer layer on one surface of a base sheet having releasability, and a transfer layer of the transfer sheet on the surface of the resin receiving layer of a metal sheet provided with a resin receiving layer on at least one surface. Side by side, the metal sheet and the transfer sheet are heated and pressed between the metal heating roll heated by an induction heating method and the rubber elastic pressure roller in contact with the metal heating roll, and the transfer layer and the resin. This is a method for producing a metal sheet with a painting, which comprises adhering a layer to the layer, and then peeling and removing the substrate sheet from the transfer layer.

[0009]

1 is a sectional view of a transfer sheet (a) used in the present invention, a metal sheet (b) provided with a resin receiving layer, and a painted metal sheet (c) obtained by the production method of the present invention. Is. According to the method for producing a metal sheet with a painting of the present invention, the transfer sheet N and the metal sheet B coated with the resin receiving layer 2 are superposed on each other, and between the metal heating roll MR and the impression cylinder GR of the elastic body. It is a method of allowing transfer to a metal sheet at high speed and good adhesion by pressurizing and heating through it.

The transfer sheet N used in the present invention comprises a release sheet 4, a decorative layer 6, an adhesive layer 5, etc. as a transfer layer on a releasable base sheet 3. Of the layers forming the transfer layer, the layers other than the decorative layer are not essential and are formed as necessary. As the base material of the transfer sheet, a film or sheet 3 having a thickness of about 12 to 100 μm and formed by the following resin is usually used. Examples of the resin forming the film or sheet 3 include polyolefins such as polypropylene and polymethylpentene, linear polyesters such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate,
Polycarbonate, polyimide, polyarylate, polyetheretherketone, cellulose acetate and the like are non-stretched or stretched films or sheets obtained by film-forming these resins. Further, it is also possible to suitably use a paper such as a wood-free paper coated with a releasable resin such as polymethylpentene or a silicone resin, which uses a resin that is unlikely to change in dimension due to heat or stress. Further, the surface of each of the base materials is preferably in a matte state for adjusting the gloss of the transfer surface. Further, if necessary, a release layer may be provided on the substrate sheet in order to promote the releasability between the transfer layer and the release substrate sheet. Here, the release layer is a layer that remains on the base material sheet side even after transfer and facilitates separation from the transfer layer,
The release layer is a layer which is transferred to the transfer target side after transfer and serves as a surface protective layer of the transfer layer. Peeling with a transfer sheet of the type having a release layer is performed between the release layer and the release layer.
As the release layer, a fluororesin, various waxes, a release agent such as silicone is added to a known vehicle such as an acrylic resin, a fibrin resin, a vinyl resin or the like to form a coating film of a paint, Releasable resin, such as fluorine resin,
A resin such as silicone, melamine-based resin, polyolefin resin, ionizing radiation crosslinkable polyfunctional acrylate, polyester, or epoxy resin is applied, and a film formed by extrusion coating or the like is used.

As the peeling layer 4, a resin composition having a peeling property with respect to the peeling base material and having a desired physical property as the surface protective layer of the transfer layer after the completion of the transfer is selected. As the resin used for the release layer, it is desirable to add a fatty acid ester, paraffin wax, or polyethylene wax as a lubricant to an acrylic resin or a urethane resin so that the surface smoothness of the transferred product appears. When surface scratch resistance, chemical resistance, and stain resistance are required, a thermosetting resin such as polyester, epoxy, acrylic, or ionizing radiation curable resin may be used. The film thickness is also selected depending on the desired physical properties and the like, but is usually about 0.1 to 20 μm.

Next, the decorative layer 6 is typically a pattern layer. For such a pattern layer, an ink in which a pigment is dispersed in a binder selected from acrylic resin, urethane resin, vinyl chloride vinyl acetate copolymer, polyester, cellulose resin and the like is used. Gravure method using the ink,
Printing or coating is performed by a known method such as an offset method.
Alternatively, a metal vapor deposition layer of aluminum, chromium or the like may be formed on the entire surface or in a pattern. As a decorative layer,
It may be a functional layer such as a hard coating film or a water repellent coating film.

A heat-sensitive adhesive is used as the adhesive layer 5.
A heat-sensitive adhesive is a material that exhibits adhesiveness when heated,
Usually, a thermoplastic resin, an ionomer, a thermosetting resin or the like is used. Examples of the thermoplastic resin include polystyrene, a styrene resin such as poly α-methyl styrene or a styrene copolymer, or an acrylic resin such as polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polybutyl acrylate, or poly. One kind or a mixture of two or more kinds of vinyl acetate, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl butyral and other vinyl polymers is used.
Further, as the thermosetting resin, a phenol resin, a diallyl phthalate resin, a polyurethane resin using a blocked isocyanate as a cross-linking agent, or the like is used. The adhesive layer 5 is formed by applying by gravure coating, roll coating, offset coating, or the like.

The thickness of the transfer layer portion of the transfer sheet of the present invention is 2 to 20 μm, preferably 3 to 15 μm. That is, when the thickness is 2 μm or less, the burr is flexible when the burr of the transfer layer is generated, and it is difficult to remove the burr by a deburring device using a brush or an operator. If the thickness exceeds 15 μm, foil burrs are likely to occur. In addition, the thermal conductivity is poor, the adhesion is poor, and the thicker the coating is, the thicker the winding becomes, resulting in an increase in weight and waste of storage space.

Next, the metal sheet B which is a heat transfer target will be described. The metal sheet 1 provided with a resin receiving layer, which is a base of a metal blind, for example, may be a flat sheet or a plate, and the thickness thereof is approximately 0.
The target is about 1 mm to 10 mm. The material is iron, aluminum, copper, brass, bronze, nickel, titanium and the like. When the metal sheet is a flexible thin material, it is preferable to supply it as a long strip-shaped sheet (web). The resin receiving layer 2 receives the transfer layer on the surface of the metal sheet and adheres to and integrates with the transfer layer, and also adheres itself to the metal sheet 1. If the transfer layer itself of the transfer sheet N to be used has sufficient adhesive force with metal, it can be omitted. The resin system constituting the resin receiving layer 2 used in the present invention includes acrylic resin, polyester resin,
A urethane resin, an epoxy resin, a polyamide resin, a polyvinyl chloride resin, a vinyl acetate resin, a melamine resin, or a mixture thereof can be used, and if necessary, an extender pigment composed of fine particles such as silica and calcium carbonate, a coloring agent. Alternatively, a heat stabilizer or the like may be added.

The transfer method of the present invention will be described. 2 and 3 are explanatory views in which the basic structure of the transfer machine for carrying out the present invention is simplified. Resin receiving layer 2 of transfer target B
And the transfer layer side of the transfer sheet N (adhesive layer 5 side in the case of the transfer sheet of FIG. 1) facing each other, the induction-heated metal heating roll (also simply referred to as metal roll) M of the present invention.
Between the R and the pressure rubber roll GR, the transfer sheet N is passed so that the base sheet side is the metal roll side MR and the metal sheet side is the pressure rubber roll GR side (FIG. 2). The painting on only one side of the metal sheet is completed by passing it once between the metal heating roll and the rubber pressure roll, but when painting on both sides of the metal sheet B,
As shown in FIG. 3, transfer sheets N1 and N2 are superposed on both sides of a metal sheet having a resin receiving layer 2 provided on both sides, and heat and pressure are applied to each side one by one to transfer the images to both sides in one step. Is possible. The heating roll is made of metal, and the heating method of the metal roll MR is an induction heating method. An internal or / and external heating method with a heater is also possible, but the induction heating method is preferable in terms of temperature rising rate and temperature stability. Induction heating is a heating method that utilizes heat generated by hysteresis loss, eddy current loss, or both that occur when an alternating electromagnetic field is applied to a metal.

As the material of the metal roll MR used in the present invention, aluminum or aluminum alloy such as duralumin is particularly preferable in view of workability, cost and heat conductivity. In addition, iron, copper, etc. can also be used. If necessary, a chrome-plated or fluororesin-coated surface may be used. In addition to the reason why the metal roll MR is used in the present invention, the heating and pressing metal roll (hereinafter referred to as a metal roll) is less likely to be damaged by heating, is maintenance-free, and has a high thermal conductivity. Is possible, resulting in high productivity. Incidentally, the silicone rubber roll is not worth using because it is greatly damaged by heating and its thermal conductivity is low.

A rubber elastic pressure roll (hereinafter referred to as a rubber roll) is used as the pressure rubber roll, that is, the impression cylinder, which is arranged to face the metal roll. The rubber roll provided so as to be in contact with the metal heating roll MR supplies pressure necessary for transfer when the transfer sheet and the metal sheet pass between the rolls, and also performs thermal insulation. As a rubber elastic material of the rubber roll GR, a material such as silicon rubber or fluororubber having high heat resistance and a thermal conductivity smaller than that of metal is used. In order to prevent bending and deformation as an impression cylinder and to have strength, the structure is such that a rubber elastic body is coated around a metal core.

FIG. 4 is a diagram showing a practical method of double-sided painting. Hereinafter, a practical transfer painting method in the transfer step to the metal sheet B having the receiving layers on both sides will be described.
Rolled metal sheet B and transfer sheet N1, respectively
N2 and the metal sheet B having resin receiving layers on both sides are sandwiched (the transfer layer surface of the transfer sheet is on the metal sheet side), and the transfer sheet N1 is on the metal roll MR1 side. Supply between MR1 and rubber roll GR1. At this time, the metal roll MR1 supplies heat necessary for adhesion to the transfer sheet and the metal sheet, and the rubber roll G1
R1 supplies pressure necessary for adhesion and at the same time prevents heat that has penetrated into the metal sheet from escaping. Next, the transfer sheet N2 is supplied between the metal roll MR2 and the rubber roll GR2 so that the transfer sheet N2 side is the metal roll MR2 side. At this time, the metal roll MR2 applies the heat necessary for adhesion to the transfer sheet B.
And the rubber roll GR2 supplies the pressure necessary for the close contact and at the same time performs thermal insulation of the metal sheet. The metal sheet B sandwiched between the two pairs of the metal roll and the rubber roll is rotated in the opposite direction around the shaft core by using an electric motor or the like so as to send out the metal sheet B sandwiched between them in one direction. The metal roll MR and the rubber roll GR are usually pressed by a known mechanism such as a hydraulic cylinder at a pressure of about 0.1 to 10 kg / cm ² . Then, only the base material sheet 3 of the transfer sheet is peeled off and wound up as winding rolls WR and WR to be removed.

Regarding the conduction of heat in the present invention, as shown in FIG. 7, a metal sheet (low temperature object 2) which is a transferred material
Is sandwiched between a metal heating roll (high temperature object 1) and a pressure rubber roll (low temperature object 3) made of a rubber elastic body, and the thermal conductivity K is K ₁ (heating roll) as shown in FIG. K ₂ (metal sheet) and together large cities, K ₃ a (pressure rubber roll) was small. As a result, a large amount of heat is input per unit time from the metal roll MR toward the inside of the metal sheet B, and the heat rapidly and generally diffuses throughout the metal sheet having high thermal conductivity. However, since the rubber roll GR behind is low in thermal conductivity, the amount of heat transferred (heat flow) from the metal sheet to the impression cylinder (low temperature) side per unit time is small. Therefore, the inside of the metal sheet is quickly brought into a thermal equilibrium state, and the temperature rise amount ΔT and the depth (Δx) of the temperature rise region are both large.

[0021]

Example The materials of the transfer sheet and the metal sheet had the following specifications. (1) As a transfer sheet, a 26-μm thick biaxially stretched polyester film (X44 manufactured by Toray) was used as a substrate, and a release layer, a decorative layer, and an adhesive layer were sequentially provided on the substrate by a gravure printing method. The decorative layer was a wood grain pattern layer, and the other layers were all solid layers. The respective grades and dry coating amounts were as follows. Release layer Removable ink: (Acrylic resin) coating amount 2g / m ² Decorative layer Pattern ink: (Acrylic resin) coating amount 2g / m ² Adhesive layer HS: (Vinyl chloride vinyl acetate copolymer) coating amount 1g / m ² (2 As a transfer-receiving sheet, an ink having the following composition was applied to an aluminum sheet having a thickness of 100 μm and dried at 200 ° C. for 30 seconds to form a resin-receiving layer. Acrylic resin 16.5% Melamine resin 10.4% Epoxy resin 10.5% Titanium oxide 20.0% Solvent (MEK / toluene / IPA) 42.6% (1/1/1)

The transfer foil obtained by the above method was applied to both sides of coated aluminum using the same transfer machine as in FIG. 4, the adhesive side of the transfer sheet was applied to the resin receiving layer coating surface of the metal sheet, in this embodiment both sides. They were placed facing each other and passed between a heat roll made of aluminum heated to 170 ° C by induction heating and an impression cylinder composed of a roll coated with silicon rubber around the iron core. The pressure between the transfer rolls was 2 kg / cm. "Transfer sheet / Aluminum sheet / Transfer sheet" The front and back surfaces of the laminate were sequentially heated and pressed. Then, after the laminate of "transfer sheet / aluminum sheet / transfer sheet" was cooled to room temperature (25 ° C), only the base sheet was peeled off to obtain an aluminum sheet having a pattern on both sides. The transfer speed is 20 m / min. It was twice as much as the conventional technology. The state of the obtained painted surface and the adhesive strength of the painted metal sheet were satisfactory. In the above description, the metal roll is placed on the base sheet side, and the rubber roll is placed on the metal sheet side. However, in the present invention, the metal roll is placed on the metal sheet side and the rubber roll is placed on the base sheet. It is also possible to place it on the side.

[0023]

EFFECTS OF THE INVENTION It is possible to manufacture a painted metal sheet with good adhesion at high speed by the thermal transfer method. That is, the transfer sheet / metal sheet has a high temperature rising rate and can be uniformly heated to a sufficiently high temperature. We were able to provide technology with high productivity and clear painting.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a transfer sheet, a metal sheet, and a painted metal sheet used in the present invention.

FIG. 2 is a principle diagram showing a painting method of the present invention.

[Fig. 3] Same as above, with a method of painting on both sides.

FIG. 4 is an explanatory diagram of a practical machine.

[Figure 5]

FIG. 7 is an explanatory diagram related to heat transfer in thermal transfer.

FIG. 8: A method for painting on a metal sheet according to the prior art

[Explanation of symbols]

 1 Base Material of Metal Sheet 2 Resin Receptive Layer 3 Base Material of Transfer Sheet 4 Release Layer 5 Adhesive Layer 6 Pattern Layer H Heater SGR Silicon Rubber Roll N Transfer Sheet B Metal Sheet P Painted Metal Sheet MR Metal Roll GR Rubber Roll DR Guide Roll WR Winding of released base material sheet after transfer

Claims (1)

[Claims] 1. A transfer sheet in which at least a decorative layer is provided as a transfer layer on one surface of a base sheet having releasability,
A metal heating roll heated by an induction heating method and a rubber elastic pressure roll in contact with the metal heating roll, which is heated by an induction heating method, are superposed with the transfer layer side of the transfer sheet facing the resin receiving layer surface of the metal sheet provided with the resin receiving layer on at least one surface Between the metal sheet and the transfer sheet, heating and pressing are performed to bond the transfer layer and the resin layer together, and then the base sheet is peeled off from the transfer layer. A method for producing a painted metal sheet.