JP2000153575A - Production of fluoroplastic-coated metal panel, and method for applying and drying adhesive for fluoroplastic suitable therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a fluoroplastic-coated metal panel excellent in the adhesiveness of fluoroplastic and a metal panel and to provide a method for applying and drying an adhesive for fluoroplastic suitable for producing the fluoroplastic- coated metal panel. SOLUTION: An adhesive soln. containing a resin having a polar group as an essential component is applied to at least one surface of a metal panel and an adhesive soln. containing fluoroplastic as an essential component is applied to the upper layer of the adhesive soln. without drying the coated layer and, thereafter, these adhesive solns. are dried and, further, the resin having the polar group and fluoroplastic are softened or melted to bond a fluoroplastic film to the surface of the adhesive in a softened and molten state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a fluororesin-coated metal sheet having excellent fluororesin adhesion, and a method for applying and drying a fluororesin adhesive suitable for producing the metal sheet.

[0002]

2. Description of the Related Art Fluororesins have excellent properties such as heat resistance, corrosion resistance, stain resistance, non-adhesion, slidability, insulation, chemical resistance and nonflammability. If this fluororesin can be firmly adhered to a metal plate, a laminated material having both the functions of the above-mentioned fluororesin and the excellent functions of the metal plate, such as high strength and workability, can be obtained. Materials suitable for the application can be provided. However, fluororesins have poor adhesion to metal surfaces due to their excellent non-adhesiveness, and many measures for improving adhesion have been proposed.

For example, Japanese Patent Application Laid-Open No. 5-162243 discloses a coated steel sheet obtained by heat-sealing a fluororesin film via a base treatment layer made of a mixture of a fluororesin and a heat-resistant resin. JP-A-6-264000 discloses a method in which a primer composition comprising a fluororesin, polyethersulfone, polyamideimide and / or polyimide and a metal powder is applied to a metal surface, and a fluororesin film is heat-sealed. I have. JP-A-10-193513 discloses a method of applying a primer composition comprising a fluororesin, an incompatible thermoplastic resin having a high surface energy and a hydrophilic pigment to a metal surface, and heat-sealing the fluororesin film. It has been disclosed.

[0004] These prior arts are characterized by the composition of a primer for bonding the fluororesin film to the surface of the metal plate. That is, by using a fluororesin excellent in heat-fusibility with a fluororesin film and a primer composed of a polar resin excellent in adhesion to metal,
It is intended to firmly bond the fluororesin film and the metal plate. The adhesion mechanism between the fluororesin film and the metal plate in the above-mentioned prior art is based on the fact that a fluororesin having a relatively low surface free energy is concentrated on the surface of the primer film by coating and baking a primer on the metal plate, The method utilizes the fact that a polar resin having a relatively high concentration is concentrated on the metal plate side, and is characterized in that a fluororesin and a fluororesin film, which are largely interposed on the surface of the primer film, are melted and fused together.

[0005]

Among the above-mentioned prior arts, the technique disclosed in Japanese Patent Application Laid-Open No. Hei 10-193513 has greatly improved the film adhesion of a fluororesin film laminated steel sheet. To improve this, increase the amount of fluororesin interposed on the primer layer coating surface as much as possible,
At the same time, the increased cohesive force of the primer coating in the film contributes.

[0006] However, the film adhesion is not sufficient for using the fluororesin film laminated metal sheet manufactured by the conventional technique in applications exposed to high temperatures, such as baking molds for baking various foods. It is necessary to further enhance the adhesion. This is because JP-A-10-1935
In the fluororesin film-laminated metal plate of JP-A No. 13, although the adhesion of the portion where the film and the primer are heat-sealed is sufficient, the actual condition is that fine adhesion failure portions still remain. . This is because, in such a situation, when various foods are baked as a baking mold, the film may swell or peel off starting from a minute poor adhesion portion.

In order to solve such a problem, it is conceivable to take measures such as lengthening the baking time after the primer coating or heating the film again after laminating the film. However, even if these measures are taken, the effect is not sufficient, and if the heating time is lengthened or reheated,
An obstacle such as deterioration of the fluororesin or a significant decrease in the production efficiency occurs. Therefore, an object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method for producing a fluororesin-coated metal plate having excellent adhesion between the fluororesin and the metal plate. Another object of the present invention is to propose a method of applying and drying a fluororesin adhesive suitable for producing a fluororesin-coated metal plate.

[0008]

Means for Solving the Problems The inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, after forming a primer layer on the surface of a metal plate through the following steps, a fluororesin film is bonded. Then, they found that the fluororesin film and the metal plate were firmly joined via the primer layer. (1) An adhesive solution (a) containing a polar resin having an adhesive property to a metal plate as an essential component is applied to the surface of the metal plate. (2) Without drying the adhesive solution (a), an adhesive solution (b) containing a fluororesin as an essential component is applied thereon. (3) Dry these adhesive solutions. (4) Further heating is performed to melt or soften the polar resin and the fluororesin, and in this state, the fluororesin film is bonded to the upper surface of the adhesive layer. In addition, the layer which bonds a metal plate and a fluororesin film is also called a primer layer. Therefore, in the present invention, the layer obtained by drying the adhesive solution (a) and the adhesive solution (b) corresponds to the primer layer.

That is, the present invention provides a method of applying an adhesive solution (a) containing a resin having a polar group as an essential component to at least one surface of a metal plate, and then drying the adhesive solution (a). Instead, an adhesive solution (b) containing a fluorocarbon resin as an essential component is applied to the upper layer of the adhesive solution (a), and then these adhesive solutions are dried. A method for producing a fluororesin-coated metal plate, characterized by softening or melting a fluororesin and bonding a fluororesin film to the surface of the softened and molten adhesive. Also, the present invention provides an adhesive solution (a) containing a resin having a polar group as an essential component on at least one surface of a metal plate, and then drying the adhesive solution (a) without drying the adhesive solution (a). An adhesive solution (b) containing a fluororesin as an essential component is applied to the upper layer of the adhesive solution (a), and then the adhesive solution is dried, which is suitable for producing a fluororesin-coated metal plate. This is a method of applying and drying a fluororesin adhesive. The adhesive solution (a) preferably contains a fluororesin in addition to the resin having a polar group. The polar group preferably contains at least one of a hydroxyl group, a carbonyl group and a sulfonyl group.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors presume the mechanism by which a fluororesin film-coated metal sheet produced by the method of the present invention exhibits excellent adhesion as follows. By overlapping and coating the adhesive solution containing the polar resin and the adhesive solution containing the fluororesin, the fluororesin and the polar resin are appropriately diffused in the medium, and both resins are not separated into layers, and the primer layer is It is interposed with a concentration gradient that is inclined in the thickness direction. Further, the amount of the fluororesin interposed on the surface of the primer layer increases, and the fluororesin film is firmly adhered.
On the other hand, a large amount of polar resin is interposed on the surface of the metal plate and strongly adheres to the metal plate. Due to these effects, the cohesive force in the primer layer is increased, so that when the fluororesin film is peeled from the finally obtained fluororesin film-coated metal plate, the interlayer is not easily delaminated in the primer layer, It is considered that high film adhesion is exhibited. Hereinafter, the present invention will be described in detail.

As the metal plate used in the present invention, an iron plate, a steel plate (including a stainless steel plate), an aluminum plate and the like can be applied. In addition, these metal plates may be subjected to various types of plating such as Al-Zn alloy plating, Zn-Fe alloy plating, Al-Si alloy plating, Zn-Ni alloy plating, Can also be applied.
In addition, since the method of the present invention is applicable to a continuous process, in order to utilize such advantages, it is preferable that these various metal plates have a coil shape.

The adhesive solution (a) of the present invention is an aqueous or solvent-based liquid medium containing a resin having a polar group described below (hereinafter abbreviated as "polar resin"). The liquid medium may be any as long as it disperses or dissolves the polar resin, but the polar resin is more preferably dissolved in the liquid medium. In this case, polar solvents such as acetone, diacetone alcohol, N-propyl alcohol, epichlorohydrin, cyclohexanone, methylcyclohexanone, isophorone, acetophenone, and N-methylpyrrolidone are preferably used.

The polar resin is a resin having a polarity in the molecule. Examples of the polar group having an adhesive property to a metal plate include a hydroxyl group, a carbonyl group and a sulfonyl group. Among them, those having a melting point or a softening point of 150 ° C. or more are preferable in order to develop film adhesion at high temperatures. For example, polyethersulfone (PES), polyarylate, polyetheretherketone (PEEK),
Polyamide imide (PAI), polyimide (PI) and the like can be mentioned, among which PES is particularly preferable. The liquid medium and the polar resin may each be composed of a plurality of types. Further, a resin component other than the polar resin may be included. In particular, it is preferable to contain a fluorine resin in addition to the polar resin. As the fluororesin, those exemplified as the fluororesin in the adhesive solution (b) described later can be used. However, when a resin component such as a fluororesin is contained in addition to the polar resin, the ratio of the polar resin (a) to all the resin components is preferably 5 to 100% by weight. The reason is that if it is less than 5% by weight, the adhesive strength between the adhesive and the metal plate is insufficient. A particularly preferred weight ratio between the polar resin and the fluororesin is polar resin: fluororesin = (10 to 50) :( 90 to 50).

The adhesive solution (a) is provided with a pigment exhibiting a design property to impart a design property without impairing the film adhesion of the finally obtained fluororesin film laminated metal plate. can do. The pigment expressing the design here is a known coloring pigment or a brilliant pigment, for example, carbon black, iron black, graphite,
Zinc yellow, yellow iron oxide, loess, titanium yellow, red iron, red lead, zinc white, lead white, basic lead sulfate, lead sulfate, lithopone,
Titanium oxide, antimony oxide, alumina white, gloss white, satin white, gypsum, aluminum powder, bronze powder, copper powder, zinc powder, various metal fibers, and the like can be used by mixing a plurality of types. it can. Although the amount of the pigment is not particularly specified, it is usually an adhesive solution.
1 to 150 with respect to 100 parts by weight of all resin components constituting (a)
It is blended by weight.

As a method of applying the adhesive solution (a) to a metal plate, a method generally used in industry such as spray coating, a roll coater, a flow coater, a knife coater, etc. can be applied. The thickness of the adhesive (a) is preferably set in a range of about 1 to 15 μm in terms of the thickness of the film after drying.

In the present invention, the adhesive solution (a) is applied, and the adhesive solution (a) is not dried (no solvent is removed). Apply adhesive solution (b). Thus the adhesive solution (a)
After applying the adhesive solution (b), do not dry (remove the solvent) before applying the adhesive solution (b) because the adhesive solution (a) and the adhesive solution (b)
The reason for this is that at the contact interface, the two adhesives use the action of appropriately mixing. Therefore, from the viewpoint of such an effect, the meaning that drying (desolvation) is not performed in the present invention means that a solvent necessary for forming a mixed layer of both adhesives is left. This is a state in which the agent does not mix at all and does not reach a state of separating into two layers.

The adhesive solution (b) of the present invention contains a fluororesin described below. As a fluororesin, C-
Various fluororesins having an F bond can be used. For example, polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene-perfluoroalkylvinylether copolymer (EPE), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), polytetrafluoroethylene (P
TFE) and the like. From the viewpoint of heat resistance, FEP, PFA, PTFE or a mixture thereof is particularly suitable.

In this case, the type of the liquid medium is not specified.
The same liquid media as those used for the adhesive solution (a) can be used. Among them, those in which a fluororesin is dispersed are preferred. In this case, the dispersed particle diameter of the fluororesin is preferably 10 μm or less in average particle diameter. When the average particle diameter is more than 10 μm, the amount of the fluororesin on the surface of the primer layer becomes insufficient, and the heat-fusibility with the fluororesin film is impaired, or the cohesive force of the primer layer is reduced, and the fluororesin is reduced. The adhesion of the film may be reduced. A particularly preferred dispersed particle size is 1 μm or less.

The liquid medium as the adhesive solution (b) and the fluororesin may each be composed of a plurality of types. Further, a resin component other than the fluororesin, for example, a resin containing the above-described polar resin may be used. However, when a plurality of resin components are contained, the weight ratio of the fluororesin to all the resin components is preferably set to 50 to 100% by weight. A particularly preferred weight ratio of the fluororesin is 80 to 10
0% by weight. The reason is that if less than 50% by weight,
This is because the resin other than the fluororesin is exposed on the surface of the adhesive coating, and the heat-fusibility with the fluororesin film is reduced.
When the aforementioned adhesive (a) contains a fluororesin, the adhesive
(b) preferably contains a higher concentration of fluororesin than the concentration of fluororesin in the adhesive (a).

The thickness of the adhesive layer including the adhesive (a) and the adhesive (b) is preferably in the range of 2 to 30 μm in terms of the thickness after drying. The adhesive solutions (a) and (b) may contain an antifoaming agent, a surfactant, a dispersant, a rust inhibitor, a weathering agent, a coupling agent, a thickening agent as long as the effects of the present invention are not impaired. And fillers such as rust preventive pigments, extender pigments, matting agents, and the like. In addition,
As a method of applying the adhesive solution (b) on the metal plate coated with the adhesive solution (a), spray coating, sputter coating, etc., which are generally used in industry, can be applied.

As the fluororesin film used in the present invention, various fluororesins formed into a film can be used. From the viewpoints of heat resistance and stain resistance, the types of the fluororesins are FEP and PFA. And perfluoro resins such as PTFE, and particularly, a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PF
A) is preferred. As the fluororesin film, those subjected to various treatments, such as those obtained by kneading or printing color pigments and dyes, those whose surfaces are oxidized and modified by plasma, and those mixed with antibacterial agents and inorganic fillers are used. It is possible. Although the thickness of the film is not particularly specified, from the viewpoint of cost and moldability, 10 to 10
Those having a thickness of 0 μm are preferred.

As described above, the adhesive solution (a) is applied, the adhesive solution (b) is applied without drying (without desolvation), and then drying (desolvation). .
The drying conditions are, for example, a heating temperature of 100 to 500 ° C.,
It is preferred that the heating time be 10 to 180 seconds. After drying is completed, the polar resin and the fluororesin are softened or melted by cooling once and then heated again after the drying is completed, thereby forming a primer layer for bonding the fluororesin film. From the viewpoint of energy saving, the latter method of performing these steps continuously without interposing cooling between the steps of drying and softening or melting is suitable.

After drying, the coated surface is heated to a temperature higher than the higher of the melting points or softening points of the polar resin and the fluororesin,
Preferably, heating is further performed at a temperature equal to or higher than the melting point of the fluororesin film. The normal heating temperature may be 250-500 ° C.
If the heating temperature is lower than the melting points or softening points of the polar resin and the fluororesin, the concentration of the fluororesin intervening on the surface of the primer layer becomes insufficient, and the adhesiveness of the fluororesin film is undesirably reduced. Further, when heating is performed at a temperature equal to or higher than the melting point of the fluororesin film, the bonding surface of the fluororesin film is melted at the time of bonding, and is easily bonded by heat. On the other hand, the heating temperature is 500
When the temperature exceeds ℃, the resin component constituting the primer layer may be thermally decomposed and the adhesion of the fluororesin film may be reduced. Further, the heating time is not particularly specified, but usually,
It is heated to a predetermined temperature in the range of 10 to 180 seconds. The heating method for softening or melting may be a hot air method, an infrared method, an induction heating method, or the like, which is usually performed, and is not particularly limited.

In the present invention, a fluororesin film is laminated and bonded in a state where the primer layer is melted or softened after heating. In consideration of continuous operation and ensuring high adhesion, it is preferable to perform pressure bonding with one or more rolls. In this case, it is preferable to laminate and press-bond during the temperature drop after heating the primer-coated surface. Naturally, the fluororesin film laminated metal plate of the present invention can be obtained by using a cut plate as the metal plate and pressing the film by pressing. Alternatively, the metal plate coated with the primer layer may be cooled once and then heated again to laminate and compress the film. In addition, the pressure for pressing is not particularly specified, but is usually determined by the linear pressure of the roll.
0.1 30 kg / cm, preferably set to range in terms of 0.5 to 100 kg / cm ² pressure.

[0025]

EXAMPLES The present invention will be described more specifically with reference to the following examples. Fluororesin-coated metal sheets were manufactured under various conditions shown in Table 1. With respect to the obtained fluororesin-coated metal plate, the following evaluation test on film adhesion was performed.・ Bake resistance: Place a mixture of eggs, sugar and soy sauce (mixing ratio 1: 1: 1) on the sample and place in a 260 ° C oven.
After heating for 15 minutes, a change in the appearance of the film after removal was observed. This test was repeated up to 10 times using the same sample, and the number of consecutive passes that did not cause appearance defects was investigated. Film peel strength: The sample cut into strips was exposed to 200 ° C. saturated steam for 3 hours in an autoclave.
After the sample was taken out, the film was forcibly peeled at normal temperature perpendicular to the surface of the metal plate, and the peeling load per peeling width of 1 cm of the film was measured and evaluated.

The detailed conditions of each embodiment will be described below. Inventive Example 1 0.45 mm-thick 430 previously roughened and activated
The following adhesive solution (a) was applied to the surface of the stainless steel strip using a roll coater. The film thickness was about 5 μm calculated after heating and drying. Immediately after the application of the adhesive solution (a),
The following adhesive solution (b) was spray-applied using a spray coater. After the application, heating was performed under the condition that the reached plate temperature reached 380 ° C. in 2 minutes, the liquid medium (N-methylpyrrolidone and cyclohexanone) was removed, and PES and FEP were melted or softened. Continue with fluororesin film (thickness 40
μm clear film of PFA) on the painted surface,
During natural cooling, they were continuously pressed (using three pairs of rolls, each with a linear pressure of 2 kg / cm). All adhesive layers (adhesive
The thickness of the coating after heating and drying (a) and (b) was about 10 μm. -Adhesive solution (a): A solution obtained by dissolving polyethersulfone (PES, polar resin) in N-methylpyrrolidone (medium). Adhesive solution (b): A solution in which a tetrafluoroethylene-hexafluoropropylene copolymer (FEP, fluororesin) having an average particle size of about 0.3 μm is dispersed in cyclohexanone (medium).

Invention Example 2 N-methylpyrrolidone (medium) was used as the adhesive solution (a).
Polyethersulfone (PES, polar resin) is dissolved in
Invention Example 1 except that aluminum powder (3 parts by weight with respect to 100 parts by weight of PES) was dispersed.
A fluororesin-coated metal plate was prototyped in the same manner as described above. The thickness of the adhesive layer was almost the same as that of Inventive Example 1.

Invention Example 3 N-methylpyrrolidone (medium) was used as the adhesive solution (a).
Polyethersulfone (PES, polar resin) is dissolved in the mixture, and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) (average particle diameter is about 0.3 μm)
, Carbon black (15 parts by weight per 100 parts by weight of PES), aluminum powder (3 parts per 100 parts by weight of PES)
(Parts by weight) was used, and a fluororesin-coated metal plate was trial-produced in the same manner as in Inventive Example 1 except for using a dispersion of (weight part). Note that PES: FEP in the adhesive solution (a) = 3: 1 (weight ratio). The thickness of the adhesive layer was almost the same as that of Inventive Example 1.

Invention Example 4 The following adhesive solution (a) was applied to a 0.8 mm thick aluminum-plated steel strip (the plating surface of which was previously treated with a coating type chromate solution) using a roll coater. The thickness of the adhesive (a) was about 8 μm calculated after drying. Immediately after the application of the adhesive solution (a), the following adhesive solution (b) was spray-applied using a spray coater. Next, heating is performed under the condition that the plate temperature reaches 425 ° C. in 2 minutes, the medium is removed, and P
ES and PTFE were melted or softened. Continuously, a fluororesin film (40 μm thick PFA printed film
) Was laminated on the surface to which the adhesive was applied, and was continuously pressed during natural cooling (each line pressure was 2 kg / cm using three pairs of rolls). The thickness of the entire adhesive layer (thickness after heating and drying the combined adhesives (a) and (b)) was about 13 μm. The film surface of the obtained fluororesin-coated metal plate showed a glittering appearance due to the black color of the primer layer and the aluminum powder through the printed pattern.・ Adhesive solution (a): N-methylpyrrolidone (medium)
Dissolve polyether sulfone (PES, polar resin)
In addition, carbon black (15 parts by weight per 100 parts by weight of PES), aluminum powder (3 parts per 100 parts by weight of PES)
Parts by weight).・ Adhesive solution (b): N-methylpyrrolidone (medium)
Polytetrafluoroethylene with an average particle size of about 0.3 μm
(PTFE, fluororesin).

Invention Example 5 0.45 mm whose surface was previously roughened and activated
Using a roll coater on a thick 430 stainless steel strip,
The following adhesive solution (a) was applied. The thickness of the adhesive (a) was about 10 μm calculated after drying. Immediately after the application of the adhesive solution (a), the following adhesive solution (b) was spray-applied using a spray coater. Next, heating is performed under the condition that the plate temperature reaches 380 ° C. in 2 minutes, the medium is removed, and PES, PAI, and FE are removed.
P was melted or softened. Subsequently, a fluororesin film (a clear film of PFA having a thickness of 40 μm) was laminated on the surface to which the adhesive was applied, and was continuously pressed during natural cooling (3.
The linear pressure was 2 kg / cm using a pair of rolls. In addition,
The thickness of all the adhesive layers (thickness after heating and drying the combined adhesives (a) and (b)) was about 15 μm. The film surface of the obtained fluororesin-coated metal plate had a yellow color. A film adhesion test of this sample was performed under the same conditions as in Example 1. -Adhesive solution (a): Polyethersulfone (PES) and polyamideimide (PAI) as polar resins are dissolved in a mixed solvent of N-methylpyrrolidone: diacetone alcohol = 3: 1 (weight ratio), and the like. To tetrafluoroethylene-hexafluoropropylene copolymer (FEP)
(Average particle size is about 0.3 μm), titanium yellow (total resin component 10
60 parts by weight with respect to 0 parts by weight). The mixing weight ratio of the resin components is PES: PAI: FEP = 60: 15: 25.
It is.・ Adhesive solution (b): Cyclohexanone (medium), tetrafluoroethylene-hexafluoropropylene copolymer (FEP) (fluororesin) having an average particle diameter of about 0.3 μm
What is distributed.

Comparative Example 1 0.45 mm whose surface was previously roughened and activated
Using a roll coater on a thick 430 stainless steel strip,
The following adhesive solution was applied. Next, in 2 minutes, the plate temperature reached 38
Heating is performed under the condition of 0 ° C., the medium is removed, and PES,
The FEP was melted or softened. Subsequently, a fluororesin film (40 μm thick PFA clear film) is laminated on the surface to which the adhesive is applied, and continuously pressed during natural cooling.
(The linear pressure was 2 kg / cm using three pairs of rolls, respectively.) Note that the thickness of the adhesive layer was about 10 μm. Adhesive solution: Polyethersulfone (PES, polar resin) is dissolved in a mixed solvent of N-methylpyrrolidone and cyclohexanone (mixing ratio 1: 1 (weight ratio)), and the average particle diameter is about 0.3 μm. Dispersion of the above-mentioned tetrafluoroethylene-hexafluoropropylene copolymer (FEP, fluororesin). (Equivalent to a mixture of the adhesive solutions (a) and (b) of Invention Example 1)

Comparative Example 2 A sample was prepared in the same manner as in Comparative Example 1 except that the adhesive solution was changed to the following. Adhesive solution: Polyethersulfone (PES, polar resin) is dissolved in a mixed solvent of N-methylpyrrolidone and cyclohexanone (mixing ratio 1: 1 (weight ratio)), and carbon black (PES 100 parts by weight) 15 parts by weight),
Aluminum powder (3 parts by weight for 100 parts by weight of PES)
What is distributed. (Corresponding to a mixture of the adhesive solutions (a) and (b) of Invention Example 2)

Comparative Example 3 Comparative Example 1 except that the adhesive solution was changed to the following:
A sample was made in the same manner as described above.・ Adhesive solution: Polyethersulfone (PES, polar resin) is dissolved in a mixed solvent of N-methylpyrrolidone and cyclohexanone (mixing ratio 3: 5 (weight ratio)), and the average particle diameter is about 0.3 μm. Fluoroethylene-hexafluoropropylene copolymer (FEP, fluororesin), carbon black (15 parts by weight per 100 parts by weight of PES),
Aluminum powder (3 parts by weight for 100 parts by weight of PES)
What is distributed. PES: FEP = 3: 5 (weight ratio). (Corresponding to a mixture of the adhesive solutions (a) and (b) of Invention Example 3)

Comparative Example 4 The following adhesive solution was applied to a 0.8 mm-thick aluminum-plated steel strip (plated surface of which was previously treated with a coating type chromate solution) using a roll coater. next,
Heating was performed under the condition that the reached plate temperature reached 425 ° C. in 2 minutes, the medium was removed, and PES and PTFE were melted or softened.
Subsequently, a fluororesin film (40 μm thick PFA print film (printed surface was made to be an adhesive surface)) was laminated on the surface to which the adhesive was applied, and continuously pressed during natural cooling.
(The linear pressure was 2 kg / cm using three pairs of rolls, respectively.) Note that the thickness of the adhesive layer was about 13 μm. The film surface of the obtained fluororesin-coated metal plate showed a glittering appearance due to the black color of the primer layer and the aluminum powder through the printed pattern. A film adhesion test of this sample was performed under the same conditions as in Example 1.・ Adhesive solution: Polyethersulfone (PES, polar resin) is dissolved in N-methylpyrrolidone (medium), and polytetrafluoroethylene (PTFE) (average particle diameter is about 0.
3 μm), carbon black (15 parts by weight with respect to 100 parts by weight of PES), and aluminum powder (3 parts by weight with respect to 100 parts by weight of PES). In addition, PES: PTF
E = 1: 1 (weight ratio). (Adhesive solution of Invention Example 4)
(equivalent to a mixture of (a) and (b))

Comparative Example 5 0.45 mm whose surface was previously roughened and activated
Using a roll coater on a thick 430 stainless steel strip,
The adhesive solution was applied. Next, in 2 minutes, the plate temperature reaches 380 ° C
Heating is performed under the following conditions, the medium is removed, and PES, PA
I, FEP was melted or softened. Subsequently, a fluororesin film (a PFA clear film having a thickness of 40 μm) was laminated on the surface to which the adhesive was applied, and was continuously pressed (by using a pair of rolls with a linear pressure of 2 kg / cm) while cooling naturally. The thickness of the entire adhesive layer (the thickness after heating and drying of the adhesives (a) and (b)) was about 15 μm. The film surface of the obtained fluororesin-coated metal plate had a yellow color.・ Adhesive solution; N-methylpyrrolidone: diacetone alcohol: cyclohexane = 3: 1: 2 (weight ratio) in a mixed solvent of polyethersulfone (PE
S) and polyamideimide (PAI) are dissolved, and tetrafluoroethylene-hexafluoropropylene copolymer (FEP) (average particle diameter is about 0.3 μm), titanium yellow
(60 parts by weight based on 100 parts by weight of all resin components). The mixing weight ratio of the resin components is PES: PAI: FE
P = 4: 1: 5. (With the adhesive solution (a) of Invention Example 5)
(equivalent to a mixture of (b))

Comparative Example 6 0.45 mm whose surface was previously roughened and activated
The following adhesive solution (a) was applied to a thick 430 stainless steel strip using a roll coater, and the plate temperature reached 380 ° C in 2 minutes.
Heating was carried out under the following conditions to remove the medium, followed by cooling to room temperature. The thickness of the adhesive (a) was about 10 μm. Next, the following adhesive solution (b) was spray-applied using a spray coater, and then heated under conditions that the plate temperature reached 380 ° C. in 2 minutes, the medium was removed, and PES, PAI, and FEP were removed. Melted or softened. Continue with fluororesin film (thickness 40
A Pm clear film having a thickness of μm) was laminated on the surface to which the adhesive was applied, and continuously pressed (with a linear pressure of 2 kg / cm using three pairs of rolls) during natural cooling. In addition, all adhesive layers
(Thickness after heating and drying the combined adhesives (a) and (b)) was about 15 μm.・ Adhesive solution (a): N-methylpyrrolidone (medium)
Polyethersulfone (PES, polar resin) dissolved. Adhesive solution (b): A solution in which a tetrafluoroethylene-hexafluoropropylene copolymer (FEP, fluororesin) having an average particle size of about 0.3 μm is dispersed in cyclohexanone (medium).

[0037]

[Table 1]

The evaluation test results are shown in Table 1. Table 1
According to the results of the above, the method of applying the two kinds of adhesive solvents without drying as in the present invention can be performed by mixing and applying the two kinds of adhesive solvents (Comparative Examples 1 to 5),
It can be seen that the adhesiveness of the film is much better than the method of applying the adhesive solution (b) after drying after applying (a).

[0039]

As described above, the fluororesin film-laminated metal sheet produced by the production method of the present invention has extremely low adhesive strength between the fluororesin film, the primer coating, the metal sheet and the cohesion within the primer layer. As a result, the adhesiveness of the heat-resistant and durable film is particularly excellent, so that it can be suitably used as a material for various heating cookware, a material for kitchenware, and the like. Further, according to the production method of the present invention, a highly adhesive fluororesin film laminated metal plate can be continuously and efficiently produced.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B29L 9:00 (72) Eiji Fujisawa 132-8 Sakuragicho, Wakaba-ku, Chiba-shi, Chiba F-term (Reference) 4F100 AB01A AB04 AK17C AK17D AK17E AK54B AK54E AK55B AK55E AL01B AL01E AT00A BA02 BA03 BA04 BA05 BA06 BA07 BA10A BA10D BA10E CB01B CB01C CB01E CB03C CB03E EC181 E02A11 J12B11 J02B11 J12J11A11

Claims (2)

[Claims] 1. An adhesive solution (a) containing a resin having a polar group as an essential component is applied to at least one surface of a metal plate, and then the adhesive solution (a) is dried without drying the adhesive solution (a). An adhesive solution (b) containing a fluororesin as an essential component is applied to the upper layer of the agent solution (a), and then these adhesive solutions are dried, and then the resin having a polar group and the fluororesin are softened. Alternatively, a method for producing a fluororesin-coated metal plate, comprising melting and bonding a fluororesin film to the surface of a softened and molten adhesive. 2. An adhesive solution (a) containing a resin having a polar group as an essential component is applied to at least one surface of the metal plate, and then the adhesive solution (a) is dried without drying the adhesive solution (a). An adhesive solution (b) containing a fluororesin as an essential component is applied to the upper layer of the agent solution (a), and then the adhesive solution is dried. How to apply and dry resin adhesive.