JPH06285991A - Manufacture of laminated metal plate - Google Patents

Abstract

PURPOSE:To improve adhesive properties, processibility, corrosion resistance and external appearance and to manufacture a metal plate with high yield by covering with a thermoplastic resin film, injecting gas from a hole opened at a surface of a winding roll so as not to bring the film fed from the plate into contact with the roll, and peeling the film from the roll. CONSTITUTION:A width of a thermoplastic resin film 3 fed down to the gap between a press-bonding roll 5 and a metal plate 1 is set larger than that of the plate 1. The entire width of the plate 1 is covered at a lateral center of the film 3. Simultaneously, a vicinity of a pressure contact part of the roll 5 is sucked from a hole opened at a surface of a winding roll 4. Further, in order to prevent the film 3 fed largely from the width of the plate 1 from being brought into contact with the roll 4, gas is injected from the hole opened at the surface of the roll 4 of a part overcoated with resin to peel the film 3 from the roll 4.

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 thermoplastic resin-coated metal sheet having excellent adhesion, workability, corrosion resistance and appearance with good 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, it becomes difficult to uniformly laminate the film on the substrate, and a phenomenon such as wrinkling occurs 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.

Regarding the method for producing a thermoplastic resin metal plate which solves the problems caused by such neck-in, is excellent in adhesion, workability, corrosion resistance, appearance and has a good yield, an opening is provided in the winding roll, About the method of injecting gas,
The applicant previously applied for Japanese Patent Application No. 4-250380.

The present invention further prevents the overcoated resin from rolling up to the pressure bonding roll side and winding around the pressure bonding roll when it is manufactured at a high speed (line speed of about 40 m / min), resulting in inoperability. Provide a way to do.

[0020]

That is, according to the present invention, a pressure roll is pressed against a preheated metal plate wound around a winding roll having an opening on the surface to form a pressure roll and a metal plate. In a method of manufacturing a laminated metal sheet by coating a thermoplastic resin film on a metal sheet by flowing a melted thermoplastic resin film from a T-die through an extruder through a extruder, heat flowing in a gap between a pressure roll and a metal sheet is used. The width of the plastic resin film is made larger than the 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. Holes opened on the surface of the winding roll in the portion where the resin is overcoated to prevent the thermoplastic resin film that has sucked in the vicinity of the pressure contact part and flows down more than the width of the metal plate from sticking to the winding roll. By injecting gas from Method for producing a laminated metal sheet, characterized in that for peeling the Aburamaku from winding roll is.

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

In the present invention, the metal substrate is a 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 having a thickness 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

[0025] Furthermore, the case where the chemical conversion treatment is not carried out or the chemical conversion treatment is carried out and thereafter an adhesive layer is provided thereon is also included.

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 modified polyethylene resin, modified epoxy resin, 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, such as ethylene-vinyl acetate copolymer resin and ethylene-acrylic acid copolymer resin. 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, fluorine resin, 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 that does not lose the fluidity.

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.

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

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

When the preheating is not carried out or when the preheating temperature is low, particularly when a cooling roll is used, the adhesion of the resin is insufficient and the corrosion resistance is deteriorated.

The higher the preheating temperature, the better the fluidity of the resin, which is preferable. However, if the preheating temperature is too high, the resin and the adhesive are decomposed, which is not preferable. 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 on 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. In the present invention, however, since the opening is provided in the surface of the axial portion of the winding roll covered with the thermoplastic resin film, The area covered by the roll surface of the resin is reduced by the opening area, and the adhesive force of the resin on the roll surface is reduced accordingly.

Further, since the gas supply mechanism for supplying gas to the hole of the opening covered with the thermoplastic resin film behind the pressure contact position is provided, the winding roll is not disturbed without disturbing the thermoplastic resin film flowing down from the T die. The resin film covering the surface floats by the gas.

Furthermore, since the gas injected between the floating resin film and the roll surface flows, the resin film is cooled and the roll surface is also cooled, and the adhesive force of the resin to the roll surface is further reduced ( Japanese Patent Application No. 4-250380).

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. In addition, an opening hole is provided at the rear of the pressure contact position of the nip roll (compression roll) 5 to inject gas from the hole.

FIG. 3 shows that, as a method of supplying gas to the holes, a wind box that slides on the inner peripheral surface of the roll is provided.

Further, in FIG. 3, the gas is jetted in a region where the metal plate 1 is separated from the winding roll 4 behind the pressure contact position of the nip roll 5, but the wind box is extended and coated with the thermoplastic resin. Even for the surface of the winding roll which is not wound, if the gas is jetted, the temperature of the roll surface is further lowered, and the cooling of the thermoplastic resin coating the roll surface can be promoted.

Further, if the wind box is divided in the circumferential direction, the strength of the gas injection can be increased or decreased, or a finer gas injection pattern can be realized.

However, the position where the gas is jetted should be such that the molten thermoplastic resin flowing down from the T-die does not sway, or the position where the molten thermoplastic resin cannot stably flow down is taken into consideration. It is necessary to select an appropriate position depending on the plastic resin.

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.

Further, gas is supplied to the holes by providing a wind box 9 that slides on the inner peripheral surface of the roll, and the gas is supplied to the wind box by a gas supply pipe 61.

This air box is equipped with a socket 56,
Since the spring 58 is connected to the shaft portion and is pressed against the inner peripheral surface of the roll by the spring 58 inserted in the socket, the leakage of gas is small.

Further, 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 can be moved in the axial direction together with the socket. Therefore, it is possible to cope with a change in the width of the metal plate to be passed.

If the jet width of the wind box in the axial direction of the winding roll is the same as the resin width of the thermoplastic resin coating the roll surface, the jet gas can be effectively jetted to the thermoplastic resin.

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.

In the present invention, when manufacturing at a high speed (line speed of about 40 m / min), the overcoated resin rolls up to the pressure bonding roll side and winds around the pressure bonding roll, making it inoperable.

Therefore, the overcoated resin is sucked in the vicinity of the pressure contact and once adhered to the winding roll side, and the overcoat resin is prevented from adhering to the winding roll by the downstream injection.

Particularly, a resin having a polar group,
For example, in polyethylene terephthalate (PET), the resin easily adheres to the roll by pressure bonding, and therefore the improvement of the present invention is effective.

That is, the resin film is sucked to the winding roll side in the vicinity of the pressure contact, for example, about 10 to 30 mm downstream from the pressure contact to prevent the resin film from being wound on the pressure bonding roll side.

Next, based on the conventional method, gas is jetted from the opening over, for example, about 200 mm downstream to prevent the overcoat resin from adhering to the winding roll (FIG. 7).

[0069]

[Embodiment 1] Next, an embodiment will be described.

In the apparatus as shown in FIG. 8, the metal plate pre-heated by the winding roll 4 in which the outer surface of the metal sleeve 51 is covered with the polytetrafluoroethylene rubber 52 as the roll around which the metal plate is wound. 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.

Further, the wind box 9 was installed so that, when the winding roll 4 and the nip roll 5 were brought into pressure contact with each other, air was blown out only from the region A at the end point of the metal plate winding immediately after the pressure contact portion.

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.

Immediately after the coating of the PET resin 3 onto the metal plate 1 was started, air was blown out from the through holes of the winding roll 4, and the resin protruding from the metal plate 1 was covered with the winding roll 4.
The line speed is 20m / m
It was confirmed that the operation could be stably performed up to in.

However, as the line speed increased, the line was wrapped around the pressure contact roll (nip roll), and the pressure contact became impossible, resulting in the inability to operate.

Therefore, from the pressure contact position to 30 mm,
The operation was performed by suctioning and further ejecting air from the downstream side to the winding end point of the metal plate.

As a result, it was confirmed that the resin protruding from the metal plate was peeled off without being wound around the pressure contact roll and was not wound around the winding roll, and stable operation was possible.

Similar results were obtained even when suction was performed over 10 mm before and after the pressure contact.

As a comparative example, in the above example, when the operation was performed without using the roll for blowing out the air, the resin protruding from the metal plate was immediately wound around the roll around which the metal plate was wound, and the operation became impossible. It was

[0079]

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 explanatory view showing suction and injection of the present invention.

FIG. 8 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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Masayasu Jin Tai, No. 1 Fuji-machi, Hirohata-ku, Himeji City Nippon Steel Corporation Hirohata Works

Claims (1)

[Claims] 1. A pressure roll is pressed against a preheated metal plate wound around a winding roll having an opening on the surface, and a T die is passed through an extruder into a gap between the pressure roll and the metal plate and a T die. In the method for producing a laminated metal plate by coating a thermoplastic resin on a metal plate by flowing down a molten thermoplastic resin film, the width of the thermoplastic resin film flowing down into the gap between the pressure roll and the metal plate is It is made larger than the width and covers the entire width of the metal plate at the widthwise central part of the thermoplastic resin film, and it sucks from the hole opened on the surface of the winding roll near the pressure contact part of the pressure bonding roll, and further the metal plate In order to prevent the thermoplastic resin film that has flowed larger than the width of the film from sticking to the winding roll,
A method for producing a laminated metal plate, comprising: injecting a gas from a hole opened on a surface of a winding roll in a portion where the resin is overcoated to separate the resin film from the winding roll.