JPH06255065A - Method and apparatus for producing laminated metal plate - Google Patents

Abstract

PURPOSE:To obtain a laminated metal plate excellent in close adhesiveness, corrosion resistance and appearance and enhanced in yield by making the width of the thermoplastic resin film flowing down between a press bonding roll and a metal plate larger than that of the metal plate to coat the metal plate with the resin film over the entire width thereof at the central part of the resin film and providing holes to the surface of a winding roll at the coating part of the resin to peel the resin film from the winding roll. CONSTITUTION:By preheating a metal substrate before coating the same with a molten resin, the flowability of the resin is enhanced and the close adhesiveness of the resin to the metal substrate is enhanced. When the metal substrate is not preheated, the close adhesiveness to the resin is not sufficient and the corrosion resistance of the metal substrate becomes inferior. Next, the width Wp of a thermoplastic resin 3 is made larger than the width WM of the metal substrate 1 on the surface of a winding roll 4 around which the preheated metal substrate 1 is wound to pass and holes 10 opened in the axial direction of the part to be coated with respect to the thermoplastic resin covering the openings formed to the surface of the winding roll 4 are provided to the winding roll 4. Air can be also injected from the holes in the rearward part from the pressure contact position of a press bonding roll 5. Even in a method injecting no air, a coating area is reduced by the opening area and the release of an overcoat resin becomes easy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a thermoplastic resin-coated metal sheet having excellent adhesion, workability, corrosion resistance and appearance with high yield.

[0002]

2. Description of the Related Art Conventionally, as a surface-treated metal plate coated with a synthetic resin, a color steel plate obtained by applying a thermosetting acrylic resin paint or a polyester resin paint, or a laminated steel plate laminated with a resin film is known. .

Due to their beautiful color, appearance and corrosion resistance, they are widely used in construction, interior materials for buses and passenger cars, materials for household electric appliances, furniture furniture and the like.

However, the resin used in the paint is
Due to the need for coating workability, relatively low molecular weight ones are used, and even after baking and baking, the high molecular weight is not sufficient, and the flow on the metal substrate is not sufficient. there were.

On the other hand, a laminated steel sheet laminated with a resin film uses an extruded film made of a resin such as vinyl chloride resin, acrylic resin or fluororesin which has a consistently high molecular weight at a petrochemical plant. However, the molecular weight is also much higher than that of the resin for paints, and therefore the durability of the coating film on the substrate is significantly longer, for example, about 10 to 20 years, compared to 3 to 5 years in the case of applying the paint. Is.

However, in this case as well, there are various problems as follows. (1) When the thickness of the film is reduced, uniform lamination on the substrate becomes difficult, and phenomena such as wrinkling occur on the surface. Therefore, the thickness is usually limited to about 50 μm.

(2) Since the substrate has microscopic unevenness, a space is likely to be formed between the solidified film and the substrate, and the adhesion of the film is insufficient.

(3) Since it is once formed as a film, there are restrictions on the resin used in terms of film forming ability.

On the other hand, the metal substrate is 50 on the heating roll.
Preheated to a temperature in the range of ~ 170 ° C, then progresses through the gap between the heating roll and the cooling roll, and the molten resin is extruded into the gap between the metal substrate and the cooling roll preheated by the heating roll, and the molten resin is laid on the metal substrate. It has been reported that a surface-treated metal plate having a beautiful appearance and excellent adhesion and corrosion resistance as compared with the conventional color steel plate or laminated steel plate can be obtained by pressure-bonding to the plate (Japanese Patent Application Laid-Open No. 2000-242242). 57-203545).

This metal plate has markedly superior adhesion to the substrate and corrosion resistance as compared with the conventional metal plate. further,
Since the coating is performed in a molten state directly from the T-die without forming a film, the film thickness is 50 μm or less, which is difficult with the conventional film coating, and 35 μm or less.
It became possible to coat up to about μ thickness.

Since the durability of the surface-treated metal plate is greatly influenced by the type of thermoplastic resin and the film thickness, it is desirable that the film thickness can be controlled according to the required degree of durability and the price. However, the present invention enables coating with a thin film.

Further, for example, a hard resin or the like can be formed into a film, but it is easily broken, and it is difficult to form a film and then press-bond it to a metal plate. Since it is coated in the state of having properties, even such a hard resin can be used.

Besides, since the film forming step is omitted, there is an advantage that the cost is reduced.

[0014]

However, the molten thermoplastic resin film flowing down from the slit-shaped opening of the T die narrows in width (neck-in) as it flows down from the opening, and the thermoplastic resin film below the opening is closed. The resin flow rate per unit width in the width direction of the film is uniform in the central portion, but is larger at both end portions than in the central portion.

If the width of the thermoplastic resin film is equal to or narrower than the width of the metal plate, the thickness of the coating resin in the width direction of the obtained laminated metal plate becomes non-uniform, and the width of the coating resin in the width direction is a non-uniform portion. Both ends do not become products, and it is necessary to trim the parts in a later process, which significantly reduces the product yield.

Therefore, it is necessary to cover (overcoat) the metal plate so as to have a width larger than that of the metal plate, but the overcoat resin adheres to the wound roll to make the operation impossible.

Therefore, there is a method of using a soft thin material as shown in Japanese Patent Laid-Open No. 3-158235 (FIG. 2), but the cost of the soft thin material is high.

The present invention solves the problems caused by such neck-in, and is excellent in adhesion, workability, corrosion resistance and appearance.
Provided is a method and an apparatus for manufacturing a thermoplastic resin metal plate having a good yield.

[0019]

That is, the present invention is
(1) On a preheated metal plate wound around a winding roll,
A method for producing a laminated metal plate by pressing a pressure bonding roll, flowing a thermoplastic resin film melted from a T die through an extruder into a gap between the pressure bonding roll and the metal plate, and coating the metal plate with the thermoplastic resin. , The width of the thermoplastic resin film flowing into the gap between the pressure roll and the metal plate is made larger than the entire width of the metal plate, and the entire width of the metal plate is covered by the widthwise central portion of the thermoplastic resin film. In order to prevent the thermoplastic resin film flowing down larger than the width of the film from adhering to the winding roll, an opening is provided in the surface of the winding roll in the portion where the resin is overcoated, and the resin film is wound on the winding roll. A method for producing a laminated metal plate, characterized by peeling from

(2) The opened hole is a non-through hole (1)
The described method,

(3) The method according to (1), wherein the opened holes are through holes.

(4) A winding roll around which a metal plate is wound,
Laminated metal plate comprising a pressure-bonding roll that is pressed against the wound metal plate from the opposite side, and a T-die that coats the metal plate with the thermoplastic resin by flowing down the melted thermoplastic resin film in the gap between the pressure-bonding roll and the metal plate. In the manufacturing apparatus of the above, a manufacturing apparatus of a laminated metal plate, characterized in that holes are provided in the surface of the winding roll of the resin overcoated portion,

(5) The opened hole is a non-through hole (4)
The described device,

(6) The device according to (4), wherein the opened hole is a through hole.

(7) The device according to any one of (4) to (6), characterized in that the hole diameter of the opening on the surface of the winding roll is made larger than the width of pressure contact of the pressure roll.

The present invention will be described in detail below with reference to the drawings.

In the present invention, first, as the metal substrate, the roof,
Used for building materials such as walls and partitions, materials for automobiles, materials for household appliances, furniture, cans, etc., thick steel plates, zinc plated steel plates, zinc alloy plated steel plates, tin plated steel plates, tin alloys, depending on the application. A plated steel plate, an aluminum plated steel plate, an aluminum alloy plated steel plate, a stainless steel plate, or the like is used.

Further, a layer having a chemical conversion treatment layer of about 0.1 to 5 μm is also included.

The chemical conversion treatment is carried out as a surface treatment of the metal plate in order to improve the corrosion resistance, oxidation resistance and adhesion of the metal substrate. For example, zinc phosphate treatment, iron phosphate treatment or electrolytic chromate treatment is carried out. Done by

Further, it also includes those having an adhesive layer thereon without chemical conversion treatment or after chemical conversion treatment.

The adhesive layer is a layer coated with an adhesive of at least several μ in order to improve the adhesion between the metal substrate and the thermoplastic resin.

As the adhesive, an adhesive thermoplastic resin having a functional group such as a modified polyethylene resin, a modified epoxy resin, a modified vinyl resin is suitable.

These have good adhesion to both the metal and the thermoplastic resin used for coating. For example, in the case of a polyolefin-coated steel sheet, ethylene-vinyl acetate copolymer resin or ethylene-acrylic acid copolymer resin is used. Modified polyolefins are preferred.

The thermoplastic resin used for coating in the present invention is, for example, polyethylene terephthalate resin, polyolefin resin, acrylic resin, polyester resin, polyamide resin, vinyl chloride resin, fluororesin, polycarbonate resin, polystyrene resin, ABS resin, chlorine. Polyolefin resins, urethane resins, etc. are typical, and polyolefin resins include polymers or copolymers of ethylene, propylene, 1-butene, 1-pentene, etc., and acrylic resins such as acrylic acid and meta There are polymers or copolymers of acrylic acid, acrylic acid ester, methacrylic acid ester, acrylamide, etc., polyester resins include polyethylene terephthalate, oil-free polyester, etc., and polyamide resins include so-called nylon 66, nylon. Down 6, nylon 610, nylon 1
1 and the like. Vinyl chloride resins include homopolymers and copolymers with ethylene and vinyl acetate, and the like. Fluorocarbon resins include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene resin. Fluorinated ethylene propylene resin, vinyl fluoride resin, vinylidene fluoride resin, etc.

Two or more resins may be mixed and used. Further, it may contain additives usually used in the production of a film, for example, a deterioration inhibitor, a modifier, a pigment and the like.

When coating in the molten state, a cross-linking agent such as amino resin or epoxy resin may be added within the range where the fluidity is not lost.

These thermoplastic resins are required to have weather resistance, cold weather suitability, heat resistance, scratch resistance, stain resistance, chemical resistance, deep drawing workability, etc., depending on the use of the surface-treated metal sheet. It is selected as appropriate. For example, polyolefin has excellent cold resistance, polyamide has excellent abrasion resistance,
Acrylic resin has excellent stain resistance and chemical resistance, and fluororesin has excellent weather resistance.

Polyethylene terephthalate resins are particularly useful in acid resistant applications.

The resin may be a single layer coating or a multilayer coating of the same or different resins. In the case of multi-layer coating, for example, a multi-layer T die may be used and an adhesive layer may be provided between the layers.

For example, on a steel sheet coated with an adhesive and preheated, a molten thermoplastic resin is used as a lower layer, an adhesive resin is used as an intermediate layer, a thermoplastic resin is used as an upper layer, and a three-layer T die is used. , Can be extruded in a film form, to obtain a surface-treated steel sheet directly and continuously coated in multiple layers, or an adhesive resin in a molten state on a preheated steel sheet as a first lower layer,
Surface treatment with thermoplastic resin as the second intermediate layer, adhesive resin as the third intermediate layer, thermoplastic resin as the fourth uppermost layer, extruded into a film shape with a 4-layer T-die, and directly and continuously in multilayer coating A steel plate can be obtained.

Next, the manufacturing process will be described with reference to the drawings.

The metal substrate needs to be preheated before being coated with the molten resin.

For example, in the case of polyethylene terephthalate, melting point (255 ° C.)-120 ° C. or higher (hence 135
Preheating at about 255 ° C.) is preferable.

Preheating increases the fluidity of the resin and improves the adhesion.

When preheating is not carried out or when the preheating temperature is low, especially when a cooling roll is used, the adhesion of the resin is not sufficient, resulting in lack of corrosion resistance.

The higher the preheating temperature is, the better the fluidity of the resin is, but it is not preferable because the preheating temperature is too high because the resin and the adhesive are decomposed. It is also not preferable from the viewpoint of energy saving.

Therefore, the preheating temperature is lower than the temperature of the molten resin, preferably lower than the temperature of the molten resin by 50 ° C. or more, usually about 50 to 230 ° C.

In FIG. 1, the pressure-bonding roll 5 is pressed against the surface of the preheated metal substrate 1 wound around the winding roll 4, and the interface between the surface of the metal substrate and the pressure-bonding roll 5 is passed through an extruder and T 1 shows a method for producing a laminated metal plate, in which a molten thermoplastic resin film 3 is flown down from a die 2 and the metal substrate 1 is coated with the thermoplastic resin film.

This method makes it easy to adjust the film thickness and surface condition. For example, it is easy to adjust the gloss of the surface and to add an embossed pattern to the surface.

Metal substrate 1 coated with high temperature molten resin 3
Is cooled and wound. Cooling, for example, after air cooling,
You may spray water, or even pass through the water cooling tank,
It may be passed through a cooling roll.

In this way, the surface-treated metal plate of the present invention can be obtained. However, in the present invention, since the opening is provided in the surface of the axial portion of the winding roll covered with the thermoplastic resin film, The roll surface coating area of the resin is reduced by the opening area, the adhesive force of the resin on the roll surface is reduced by that amount, and the overcoat resin does not wind around the winding roll,
It can be peeled off.

The shape and structure of the holes to be opened are not particularly limited and may be through holes or non-through holes.
Typically, it is preferable to provide holes penetrating the surface of the roll. In this case, as disclosed in Japanese Patent Application No. 4-250380, it is possible to use a method of injecting a gas from the opened hole to separate the overcoated resin from the winding roll.

Hereinafter, the case where the opened hole is a through hole will be described as an example.

FIG. 3 is a sectional view of the apparatus, and FIGS.
XX direction diagram, YY direction diagram, Z in FIG. 3, respectively.
-Z direction view.

As shown in FIGS. 3 and 4, according to the present invention, a winding roll (roll winding) through which the preheated metal plate 1 passes.
On the surface of No. 4, the width W _P of the thermoplastic resin 3 is made wider than the plate width W _M of the metal plate 1, and the thermoplastic resin covering the opening of the surface of the winding roll is axially covered with the thermoplastic resin. A nip roll (pressure bonding roll) 5
It is also possible to inject gas from the hole in the rear part of the pressure contact position.

Even in the method of the present invention in which no gas is jetted, the coating area is reduced by the opening area, and the overcoat resin is easily peeled off.

In FIG. 5, on the outer circumference of the metal sleeve 51,
The thermoplastic resin and a rubber having good releasability, for example, polytetrafluoroethylene rubber 52 are lined, and the portion covered with the thermoplastic resin has a hole 10 penetrating in the thickness direction of the winding roll.
Is provided.

The shaft structure of this device is a double pipe structure of an outer pipe 55 and a shaft 54, and a movable portion 53 is provided between the outer pipe and the shaft. An elongated hole 63 is opened in the outer tube in the axial direction so that the socket 56 can be moved in the axial direction.

Regarding the moving mechanism, the movable part and the shaft have a relationship of a nut and a bolt, and when the shaft rotates, the movable part moves with it.

That is, by rotating the shaft, the wind box for injecting gas together with the socket can be moved in the axial direction. Therefore, it is possible to cope with a change in the width of the metal plate to be passed.

This device has a structure in which the shaft is fixed and only the sleeve 51 rotates via the bearing 59.

FIG. 6 shows the positions of the holes to be opened. The hole to be opened is the minimum width W _M m of the metal plate to be passed.
It is preferable to provide it in the region from in to the resin width W _P max of the thermoplastic resin covering the roll surface in the maximum plate width W _M max.

FIG. 7 shows an enlarged view of the hole portion. The shape of the holes may be round, square, rectangular, rhombic, or any other shape.

As for the arrangement of the holes, as shown in FIG. 7, it is preferable that the holes are arranged as densely as possible in order to reduce the area covered by the roll surface of the thermoplastic resin.

Further, regarding the structure of the hole, sectional views taken along the line U--U in FIG. 7 are shown in FIGS. As shown in FIGS. 8 and 9, in order to reduce the roll surface coverage area of the thermoplastic resin, a structure in which the hole diameter on the roll surface side is made larger than the hole diameter on the inner surface side of the roll, for example, a two-step hole structure (FIG. 8) A tapered hole structure (Fig. 9) is preferable.

As to the size of the holes on the roll surface, as shown in FIG. 10, in order to avoid the thermoplastic resin from being injected into the holes due to the pressure contact at the pressure contact position with the nip roll, it is shown in FIG. It is better to make the hole larger than the nip width of the nip roll.

In the above examples, the hole is a through hole, but it may be a non-through hole as shown in FIG.

[0068]

[Embodiment 1] Finally, an embodiment using this apparatus will be described.

In a device as shown in FIG. 13, a metal plate 51 is wrapped around a metal sleeve 51, and the outer surface of a metal sleeve 51 is coated with polytetrafluoroethylene rubber 52. A winding roll 4 provided with a hole penetrating from the inside to the outside in the axial direction of the roll was provided in the vicinity of the roll surface portion where the resin protruding from the plate comes into contact when 1 is wound.

The air box 9 is not used in this embodiment.

After preheating the metal plate 1 in this way,
At the interface between the metal plate 1 and the nip roll 5, P from the T die 2
The ET resin 3 was extruded and allowed to flow down to cover the metal plate 1. At this time, the PET-based resin 3 was coated on both sides of the metal plate 1 by 50 mm.

The resin protruding from the metal plate 1 is
It was peeled off without being wound around the winding roll 4, and it was confirmed that the line speed could be stably operated up to 10 m / min.

As a comparative example, in the above-mentioned example, when the operation was carried out without using the roll having the holes formed on the surface thereof, the resin protruding from the metal plate was immediately put on the roll around which the metal plate was wound. It became wrapped around and became inoperable.

[0074]

Industrial Applicability According to the present invention, a laminated metal plate excellent in adhesion, workability, corrosion resistance and appearance can be produced with high yield.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a method for coating a molten resin by flowing it down at an interface between a metal substrate and a roll.

FIG. 2 is an explanatory view of a T-die extrusion method using a soft thin material.

FIG. 3 is an explanatory view of the method of the present invention.

FIG. 4 is a sectional view taken along line XX in FIG.

5 is a sectional view taken along line YY in FIG.

6 is a sectional view taken along line ZZ in FIG.

FIG. 7 is an enlarged view of a hole in FIG.

FIG. 8 is a cross-sectional view taken along line UU in FIG. 7 (two-stage hole type).

9 is a cross-sectional view taken along the line UU in FIG. 7 (tapered type).

FIG. 10 is a cross-sectional view of a nip roll pressing portion having a hole diameter larger than a nip width.

FIG. 11 is a cross-sectional view of a nip roll pressure contact portion having a hole diameter smaller than a nip width.

FIG. 12 is an explanatory diagram showing an embodiment.

FIG. 13 is an explanatory diagram of the first embodiment.

[Explanation of symbols]

 1 Metal Plate 2 T-Die 3 Thermoplastic Resin 4 Winding Roll 5 Crimping Roll 6 Cooling Device 7 Water Spray Cooling Device 8 Soft Thin Material 9 Wind Box 10 Through Hole 51 Metal Sleeve 52 Rubber Lining 53 Movable Part 54 Shaft 55 Outer Tube (Sleeve) 56 Socket 57 Plug 58 Spring 59 Bearing 61 Gas Supply Pipe 63 Long Hole

Claims (7)

[Claims] 1. A thermoplastic resin film melted from a T-die through an extruder by pressing a pressure roll against a preheated metal plate wound around a winding roll and passing through an extruder into a gap between the pressure roll and the metal plate. In the method of producing a laminated metal plate by flowing down and coating a thermoplastic resin on a metal plate, the width of the thermoplastic resin film flowing down into the gap between the pressure roll and the metal plate is made larger than the entire width of the metal plate, The resin was overcoated in order to cover the entire width of the metal plate with the widthwise central portion of the plastic resin film and to prevent the thermoplastic resin film flowing down larger than the width of the metal plate from adhering to the winding roll. A method for producing a laminated metal plate, characterized in that holes are provided on the surface of a winding roll of a portion, and the resin film is peeled off from the winding roll. 2. The method according to claim 1, wherein the opened holes are non-through holes. 3. The method according to claim 1, wherein the opened hole is a through hole. 4. A winding roll around which a metal plate is wound, a pressure roll that presses against the wound metal plate from the opposite side, and a molten thermoplastic resin film flows down into the gap between the pressure roll and the metal plate to flow down the metal plate. In a manufacturing apparatus for a laminated metal plate comprising a T-die coated with a thermoplastic resin, a hole is provided on the surface of the winding roll of the resin overcoated portion, and the laminated metal sheet is manufactured. apparatus. 5. The device according to claim 4, wherein the opened hole is a non-through hole. 6. The device according to claim 4, wherein the opened hole is a through hole. 7. The apparatus according to claim 4, wherein the hole diameter of the opening on the surface of the wrapping roll is made larger than the width of the pressure roll to which the pressure roll is pressed.