JPH04142927A - Film-coated metallic plate - Google Patents

Abstract

PURPOSE:To eliminate shading of color completely by controlling the difference (Rmu) between the maximum and the minimum of the thickness of a fluorine- containing resin film to or below a predetermined value, and controlling the thickness variation rate (dR) per unit width of the film to or below a predetermined value. CONSTITUTION:A 'fluorine-containing resin' is not particularly limited but may be any thermoplastic resin that contains fluorine in the molecular structural formula thereof. The difference (Ru) between the maximum and the minimum of the thickness of a fluorine-containing resin film and the thickness variation rate (dR) per 1cm film width are specified. Ru is not more than 15mum, preferably not more than 10mum, and more preferably not more than 6mum; dR is not more than 10mum/cm, preferably not more than 8mum/cm, and more preferably not more than 6mum/cm. Method of producing the fluorine-containing resin film is not particularly limited, and any of conventional methods can be used, for example, a heat-melting method or a solution casting method. The method of production is suitably selected according to the intended use of a composite metallic plate, the resin used, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal plate coated with a film, and more particularly to a metal plate coated with a fluororesin film.

[Prior Art] Various film-coated metal plates have already been proposed by the present inventors, in which a fluorine-containing resin film is heat-pressed onto a metal plate. For example, patent application Hei 1-73899
No. 1-139155, No. 1-26211, and No. 2-126572, etc., and these are mainly those printed with fluorine-containing resin films or those contained on surface-treated metal plates. It was intended to cover a fluororesin film.

In response to strong market demand, the inventors coated a metal plate with a colored transparent fluorine-containing resin film containing a small amount of coloring agent, and it became clear that the shading of the color was almost undetectable with the film alone. This resulted in a problem with marketability. Therefore, in order to make the product acceptable to the market, we continued intensive research on improvement, which led to the present invention.

[Problems to be Solved by the Invention] The purpose of the present invention is to solve the problems of the above-mentioned prior art, and to provide a film-coated metal plate that has been completely unknown in the past. It is something to do.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems, and provides a metal plate coated with a fluorine-containing resin film. The difference (Rμ) between the maximum film thickness and the maximum Jz value is 15μ or less, and the rate of change in thickness (dR) per 1□□□ film width of the fluororesin film is 10μ/c+n or less. The present invention provides a film-coated metal plate characterized by:

According to the present invention, a metal plate coated with a transparent fluorine-containing resin film containing a slight amount of a coloring agent has a film-coated metal plate that is highly marketable and has no discernable shade of color. You can get it. Next, the constituent factors of the present invention will be explained in detail.

In the present invention, "fluorine-containing resin" is not particularly limited as long as it is a thermoplastic resin containing fluorine in the molecular structure of the resin, but specifically, for example, Tetrafluoroethylene resins having four fluorine atoms, trifluoroethylene resins, difluoroethylene resins, -fluoroethylene resins, and mixtures of these resins, among others, tetrafluoroethylene resins. and trifluoroethylene resins are preferred, and tetrafluoroethylene resins are more preferred. Here, the tetrafluoroethylene resin specifically refers to, for example, a tetrafluoroethylene resin (
PTI"E), tetrafluoroethylene/perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene/hexafluoropropylene/perfluoroalkoxyethylene copolymer (EPE), and tetrafluoroethylene/ethylene copolymer There are combinations (ETFE), among others PFA, ETF
E and EPE are preferred, especially ETFE.

Specifically, ETFE is mainly composed of ethylene and tetrafluoroethylene, and the molar ratio of ethylene/tetrafluoroethylene is generally 40/60 to 60/40), and if necessary, a small amount (usually 10 mol). % or less)
In the present invention, in particular, the molar ratio of ethylene/tetrafluoroethylene is 4.
0/60 to 60/40, preferably 45155 to 55
/45 and has the formula CH2=CH-CnF2
perfluoroalkylvinyl monomer units represented by n+1 (where n is an integer from 2 to 10) (e.g., CH2=CH-C4H, or CH2=CH-C,
ET in which the content of units derived from H, , is in the range of 0.1 to 10 mol%, preferably 0.3 to 5 mol%.
FE is preferably used. This ETFE is known per se, and can be produced, for example, by the method described in Japanese Patent Publication No. 59-50163, and is also commercially available from Asahi Glass Co., Ltd. under the trade name [Aflon C0PJ]. You can also use things.

In addition, the above-mentioned trifluoroethylene resin is specifically:
For example, chlorotrifluoroethylene resin (PCTFE) and chlorotrifluoroethylene/ethylene copolymer (ECTF)
E), etc., and among them, CTEFE is preferable. Specifically, the difluoroethylene-based and -fluoroethylene-based resins include, for example, vinylidene fluoride resin (PVI) F
) and vinyl fluoride resin (PVC).

Furthermore, the "colorant" used in the present invention refers to a colorant that is added and mixed into the fluorinated resin film, and is not particularly limited, but includes, for example, white, red,
There are vermilion, yellow, green, blue, purple, and black colorants. More specifically, white colorants include, for example, zinc oxide (ZnO) and titanium oxide (TiO2).
), lithopone (ZnS+Ba5O,), zinc flux (Z
nS), red colorants include cadmium red (CdS+Cd5e), antimony red (2Sb
2S2/Sb20g), Irgazine Red, Perylene Red, vermilion colorants include iron oxide [Fe2
O,-1-(Fe0)], chromium vermilion (PbC
rO4-PbMo0. , Pb5O4), amber type (F
e2030 MnO2 + Mn304), yellow colorants include, for example, chrome yellow (PbCrO,), zinc yellow (Z n Cr O4), barium chromate (BaCrO4), cadmium yellow (CdS),
Titanium yellow colorants (TiO2/NiO5b203), ocher colorants (Fe20,5i02A1203), and green colorants include, for example, phthalocyanine colorants, chromium green colorants (prussian blue + yellow lead), and cobalt green colorants (C.

○ZnOMg0), cerulean blue (CoOnSn○
2.mMgo), blue colorants such as ultramarine (
3NaAl-3iO4・Na252), dark blue [Fe4
[Fe(CN), ], .nH2O], cobalt blue (CoOnA1203), cyanine blue, and purple colorants include, for example, cobalt purple [CO, (P 04)
21, cobalt purple [Co, (AsO,L]), dioxazine violet, and examples of black colorants include carbon black, iron black, aniline black, and cyanine black.

The amount of these colorants added is not particularly limited,
Any one is fine, but - 0.01 to 5 PHR for the crotch, preferably 0.02 to 3 PHR, more preferably 0.03
~2PHR.

Furthermore, in the present invention, it is important to define the difference between the maximum and minimum thickness of the fluororesin film (Ru) and the rate of change in thickness per film width (dR). . This Ru is the difference between the maximum value and the minimum value of film thickness in the entire film (μ), and dR is the rate of change in film thickness per 1 m of film width (μ/mark).

In the present invention, Ru is 15μ or less, preferably 10μ
Below, more preferably 6μ or less, dR is 10μ
/cnl or less, preferably 8μ/cm or less, more preferably 6μ/cIT1 or less.

In addition, the average film thickness (R) of the film is not particularly regulated, and any film thickness may be used.
00μ, preferably 10 to 200μ, more preferably 2
It is 0 to 100μ.

The method for measuring this film thickness is not particularly specified, and any conventional method may be used.

The method for producing the fluororesin film is not particularly limited, and any conventionally employed method can be used. Examples include a hot melting method and a solution casting method, which are appropriately selected depending on the purpose of the composite metal plate of the present invention and the resin used. Examples of the hot melting method include extrusion method, calendar method, and press method, and examples of the solution casting method include:
For example, there are a solvent casting method, an organosol casting method, a plastisol casting method, and the like.

The visible light transmittance (T) of the fluororesin film thus obtained is not particularly limited, but -
For the crotch, it is 20-95%, preferably 30-90%, particularly preferably 40-85%. Here, visible light is light mainly in the wavelength range of 400 to 700 nm, and T is the average transmittance in this range.

The method for measuring T is not particularly specified, and any method may be used. For example, it can also be measured using a commercially available transmission type spectrometer.

Furthermore, the term "metal plate" used in the present invention is not particularly limited, and any metal plate can be used. Among them, iron-based aluminum-based metal plates and copper-based metal plates are preferable, and iron-based and aluminum-based metal plates are particularly preferable. The above-mentioned iron-based metal plate may be any metal plate that mainly contains iron in its composition, and specifically includes, for example, a cold rolled steel plate, a galvanized steel plate, and a zinc alloy plated steel plate. , aluminum-plated steel sheets, copper-plated steel sheets, stainless steel sheets, phosphate-treated steel sheets, and aluminum-zinc alloy-plated steel sheets, among others, zinc-plated steel sheets, zinc alloy-plated steel sheets, aluminum-plated lead steel sheets, and aluminum-zinc alloy-plated steel sheets. preferable.

Further, the aluminum-based metal may be any metal as long as it mainly contains aluminum metal in its composition. Aluminum is described in pages 13 to 22 of the "Aluminum Handbook (2nd Edition)" published by the association, and specifically includes pure aluminum, (AI-Cu) series, (AI-Mn) series, (AISi) series, ( AI-Mg)
system, (Al-Mg-3i) system, and (AI-Zn-Mg
) system, among which pure aluminum system, (AI-Mn)
and (A I-Mg) series are preferred.

Further, the copper-based metal may be any metal as long as it mainly contains copper in its composition. There are metals.

The thickness of the metal plate in the present invention is not particularly limited, but it is, for example, 0.15 to 41 I□, preferably 0.2 to 2.2 IllIll.

Next, an example of the process of coating a metal plate with a fluorine-containing resin film according to the present invention will be described, and the films can be bonded by heat-melting and bonding using conventional methods. - The crotch area can be obtained, for example, by processes such as a pretreatment process, a heating process, film lamination, a pressing process, a reheating process, and a cooling process. The steps will be explained below.

(1) Pretreatment Step This step is a step that is carried out as necessary to coat the metal plate and the fluorine-containing resin film more strongly.

■ Pre-treatment process for metal plates The purpose of the pre-treatment process for metal plates is to clean and remove oily substances, foreign substances, oxide films, etc. adhering to the surface, and to expose the bare metal to the surface by polishing etc. In addition, surface treatments such as surface plating and acid treatment are performed, and if necessary, roughness is added to the surface.

a. Surface cleaning is not particularly limited, and conventional cleaning methods used for specific metals may be used. For example, as a degreasing method,
Degrease and clean using organic solvents, alkaline aqueous solutions, surfactants, etc.

=12- (1) 54 Surface Polishing The surface can be polished to expose the bare metal on the surface, for example, by mechanical or chemical polishing.

C9 Surface Treatment If necessary, the surface covered with the film may be subjected to plating treatment, coating treatment for installing a metal oxide film layer, and chemical conversion treatment for rust prevention treatment.

For example, specific examples of chemical conversion treatments for iron-based metals include phosphate treatment with zinc phosphate, calcium phosphate, etc., and chromate treatment with reactive chromate, coating type chromate, and the like.

d) Surface Roughening The surface can be roughened by a surface roughening method using physical means such as brushing, sandblasting, and shotblasting, or by a surface roughening method using a chemical or electrochemical etching method or a combination thereof.

Film pre-treatment process: removing oily matter, foreign matter, etc. adhering to the film surface, applying an oxide film etc. by corona discharge treatment, chemical treatment, etc., and using various surface treatment agents, For example, treatments such as coating aminosilane, vinylsilane, mercaptosilane, etc. can be performed.

(2) Heating process This is a process in which the pretreated metal plate is heat treated in the air or in an atmosphere substantially free of oxygen. In the present invention, the latter is preferred, and if necessary, a film may also be added. This is a process of heat treatment at the same time.

■Heating atmosphere The above-mentioned “substantially oxygen-free atmosphere” means:
There are no particular restrictions on the atmosphere as long as it can heat the metal plate and film while substantially maintaining the surface condition of the metal plate and film that underwent the pretreatment process, but specifically, the atmosphere may have an oxygen content of 1% or less, The atmosphere is preferably 0.5% or less, more preferably 0.2% or less, particularly preferably 0.01% or less. To create this heating atmosphere, it can be filled with an inert gas or heated in a vacuum state.

Any type of inert gas may be used, but in terms of numbers,
Nitrogen gas and argon gas are preferred.

In addition, the vacuum state is 5 Torr or less, preferably IT
orr or less, more preferably 0. It is less than ITorr.

■ Heating temperature The optimum heating temperature is determined by the type of fluororesin film and metal plate to be coated, but - numerically, the softening point temperature, which is the melting point of the fluororesin film ( mp) or more, preferably (mp +30) 'C
More preferably, the temperature is above (mp+50)°C and below the thermal decomposition temperature.
Generally 260-370°C, preferably 280-3
30℃, PFA generally 280-400℃, PCT
In FE, numerically 180-350°C preferably Ha210
-290°C and 250-300°C for PVDF, etc.

■ Heating time = 15- The heating time is not something that should be specified in particular, but it must be the time it takes for at least the surface of the metal plate to reach the heating temperature. determined, but - numerically from 1 to 20 minutes, preferably from 3 to 15
minutes, more preferably about 5 to 10 minutes.

(3) Lamination step This step is a step of covering a heated metal plate with a fluorine-containing resin film by lamination and pressing.

■ Lamination atmosphere The lamination atmosphere is not particularly limited, but at least in cases where films are laminated and placed on heated metal plates, it is desirable that the atmosphere be substantially free of oxygen; It is preferable to follow the previous step (2), (2).

■ A film laminated and placed on a press-heated metal plate, for example,
This is a process of continuously pressing with a book roll or the like to strongly coat the material. The roll that comes into contact with the film is preferably a rubber roll or a metal roll that does not adhere to the film, and the pressing force is 5 to 30 kg/cm2, preferably 10 to 20 kg/cm2.

(4) Reheating process This step is a reheating step that is performed as necessary to further strengthen the fusion force between the metal plate and the film of the film-coated metal plate obtained in the previous step. (1) Heating atmosphere and (2) heating temperature in this step can be carried out according to the previous section (2), (2) and (2).

■ Heating time The heating time is not something that should be specified in particular, but it needs to be the time required for at least the surface of the metal plate to reach the heating temperature, and is determined by the number of times depending on the type of metal plate, plate thickness, etc. - numerically from 1 to 20 minutes, preferably from 3 to 17 minutes;
More preferably, it is 5 to 15 minutes.

(5) Cooling Step This step is a step of cooling the reheated film-coated metal plate to room temperature, and can be cooled, for example, with an air cooling fan, water, or the like. If non-uniform cooling is performed here, distortion and deformation will occur in the plate, so uniform cooling is desirable.

The film-coated metal plate of the present invention obtained by the above process is produced by heating the metal plate and the fluorine-containing resin film in an atmosphere substantially free of oxygen to fuse and bond the metal plate and the fluorine-containing resin film. The resin film is hardly affected by oxidative deterioration, and therefore the metal plate and the fluorine-containing resin film exhibit strong adhesive strength and are thought to be usable for a long period of time.

The colored film-coated metal sheets obtained in this way are widely used in industries such as building interior and exterior materials, signboards, shutters, tunnel interior wall materials, and interior and exterior materials for vehicles such as automobiles and trains, and contribute to the industry. It's extremely large.

The present invention will be explained in more detail below with reference to Examples, but it goes without saying that the present invention should not be limited only to the Examples.

Example 1 The molar ratio of tetrafluoroethylene/ethylene is 53747
The flow start temperature is 280°C, the thermal decomposition start is 350°C, and the volumetric flow rate at 300°C is 90Il1112/
Color pellets were obtained by kneading 100 parts of a second ethylene-tetrafluoroethylene copolymer and 0.5 parts of Bengara (coloring agent) using a twin-screw extruder in the same direction. The crosstalk conditions at this time are temperature 300℃, rotation speed 1100rp, L/D = 30
Met. A non-porous colored film having an average thickness R of 50 microns is prepared by molding the color pellets by hot melt extrusion. The light transmittance of this colored film is 75%
, Rμ=8μ, dR=6. It was u/an.

On the other hand, one side of an A3052 series aluminum rolled plate specified in JIS-H-4000 with a thickness of 2.0 IN was coated with an average unevenness depth of 10 to 15 microns (surface roughness) and an unevenness period of 1.
After sandblasting to 0 to 20 microns, the sandblasted surface is electrolytically etched.

This electrolytic etching treatment was carried out using a 3% NaCl aqueous solution at a temperature of 40°C, an electrolytic density of 4 amperes/dm2, and a current flow rate of 35 clones/cm''.

=19- After washing the etched surface with water and drying it, the aluminum plate was
Preheat to 10°C, overlay the colored film on the etched surface, press it with a pressure of 20 kg/cm2, and then
This was heat-sealed by reheating at 5° C. for 10 minutes to obtain a film-coated metal plate of the present invention in which a fluororesin layer was formed on the aluminum plate.

Examples 2 to 3 In Example 1, the colorant was phthalocyanine blue (0
, 1 part: Example 2) and Bengara (1.0 parts: Example 3), and in the same manner as in Example 1, a film-coated metal plate as shown in Table 1 was obtained.

Comparative Examples 1 to 2 Film-coated metal plates as shown in Table 1 were obtained in the same manner as in Example 1, using Bengara and Phthalocyanine Blue as colorants.

The film-coated metal plate thus obtained (1.8m x
The entire surface of the 1.8 m ) surface was visually observed to investigate the degree of color shading, and the results are shown in Table 1.

Here, the criteria for determining the density phenomenon are as follows: Ta.

○... No shading can be seen on the entire surface.

△...Slight shading is seen over the entire surface.

X・ The shading can be clearly seen on the entire surface.

Table-1

Claims (1)

[Scope of Claims] 1. A metal plate coated with a fluororesin film, in which the difference (Rμ) between the maximum and minimum thickness of the fluororesin film is 15μ or less, and Thickness change rate (dR) per 1 cm film width of fluororesin film
) is 10 μ/cm or less. 2. The film-coated metal plate according to claim 1, wherein the fluororesin film has a visible light transmittance (T) of 20 to 95%. 3. The film-coated metal plate according to claim 1, wherein the fluororesin is a tetrafluoroethylene resin. 4. The film-coated metal plate according to claim 3, wherein the fluororesin is an ethylene/tetrafluoroethylene copolymer (ETFE). 5. 0.001 to 5 PHR of colorant in the fluororesin
A film-coated metal plate according to claims 1 to 3 containing the film-coated metal plate.