JP2001276946A - Oven apparatus for metallic container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the production line by suppressing an increase in plant and concurrently restrain the thermal energy consumption in the production line as low as possible, in a production line for manufacturing a container from a metal strip covered with a crystalline thermoplastic resin layer, when an apparatus for non-crystallizing the thermoplastic resin layer is installed. SOLUTION: Concerning an oven apparatus 1 for heating containers provided on the way to the production line for manufacturing containers from the metal strip coated with crystalline thermoplastic resin layer, along the direction of movement of a conveyor 4 for transferring containers which passes through an oven body 2, the inside of the oven body 2 is divided into a plurality of zones 2a, 2b, 2c having different temperatures and concurrently one 2c of a plurality of heating zones inside the oven body 2 comprises a heating zone for non-crystallizing the thermal plastic resin layer which coats the metal surface of the container and the other heating zones 2a, 2b comprise zones for the other heating process (for example, a lubricating agents removing process) required for the container production process except the non-crystallization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a can-making oven installed for heating a can in the middle of a can-manufacturing line, and more particularly to a can-making oven which is coated with a crystalline thermoplastic resin layer. The present invention relates to an oven device for amorphizing a thermoplastic resin layer covering a metal surface of a can body in the middle of a production line for producing a can body from a thin metal plate.

[0002]

2. Description of the Related Art A can body (a main body of a can) manufactured by drawing or ironing from a thin metal sheet for aluminum or steel cans is previously coated with a thermoplastic resin layer serving as a protective coating. It is conventionally well known that a can body is formed from a metal sheet, but in the production of a can body from such a coated metal sheet, coating and ironing are repeatedly performed on the coated metal sheet. Since the crystalline thermoplastic resin of the resin layer is crystallized (increased in crystallinity), its moldability becomes poor, and its adhesiveness to metal is reduced. In the trimming process (process of cutting the opening end of the can body to make the height of the can body uniform), flange processing, double winding processing, bead processing, etc., whitening and peeling of the coating resin layer are likely to occur. Such a problem occurs Fear there is.

On the other hand, as a technique for solving such a problem, Japanese Patent Application Laid-Open No. 54-141886 discloses a technique in which a thermoplastic resin is used in the production of a coated metal container (sideless seamless can body). After forming the coated material (coated metal sheet) by drawing or ironing, (Tm-5) ° C ~ 3
After heat treatment at 00 ° C. [Tm: melting point of the resin], it is immediately cooled to (Ta-30) ° C. [Ta: adhesion start temperature of the resin], so that the molded article (can body) is coated. It is described that the degree of crystallinity of the thermoplastic resin is reduced (amorphized).

Japanese Patent Application Laid-Open No. 52-65579 discloses a technique related to amorphization of a coated resin layer in the production of such a coated metal container, in which a metal coated with a thermoplastic polyester resin is molded. In order to improve the moldability and corrosion resistance, a method for adjusting the crystallinity of the resin layer before and after molding to a specified range is as follows. The coated metal formed by coating the thermoplastic polyester resin layer in the above is molded.
g) It is described that the degree of crystallinity of the thermoplastic polyester resin layer is increased to a range of 5 to 50% by performing dry heat or wet heat treatment in a temperature range higher than and 5 ° C. lower than the melting point of the crystal. .

Further, JP-A-48-49590 and JP-A-48-61584 disclose that a crystalline thermoplastic resin is thermally bonded to a metal plate so that the crystalline phase is 50 to 6%.
After a coated metal plate coated with a resin film layer of 0% and an amorphous phase of 50 to 40% is formed, the coated metal plate is formed to form a container or a container lid. It is described that a heat treatment is performed under such a condition that a balance between amorphous and crystalline is maintained in order to remove it.

On the other hand, apart from the above-mentioned known techniques for making the coating resin layer amorphous or maintaining the balance between amorphous and crystalline, a coating metal sheet covered with the resin layer is drawn. When molding a can body by processing or ironing, apply a high-temperature volatile lubricant such as wax from the top of the coating resin layer to the coated metal sheet before molding in order to improve workability during molding. In addition, by heating the can body after molding to a temperature higher than the volatilization temperature of the lubricant, a large amount of water is not required, and the two steps of the degreasing / washing step and the drying step are not required. It has been conventionally known that a lubricant is volatilized and removed from a can body (see, for example, JP-A-51-63787 and JP-A-Hei3-3679).
-226319).

[0007]

However, when a can body is manufactured from a coated metal sheet coated with a crystalline thermoplastic resin through drawing or ironing, a trimming step or neck after forming the can body is required. In order to reliably prevent the whitening or peeling of the coating resin layer from occurring in processing steps such as in-processing and flange processing, for example, the above-mentioned JP-A-54-141 is disclosed.
As described in Japanese Patent Publication No. 886, after the can body is formed from the coated metal sheet by drawing or ironing, heat before coating the can body before entering a processing step such as a subsequent trimming step. It is desirable that the plastic resin layer be made amorphous again.

In particular, a bottle-shaped two-piece can (in which the mouth, neck, shoulder, and body are integrally formed, and a separate bottom lid is fixedly fastened to the lower end of the body, and the portion excluding the cap is two members When the can body (mouth neck, shoulder, and torso) is formed from a coated metal sheet, the metal sheet is formed into a can body by drawing or ironing. Since it is necessary to further form screws and the like on the mouth and neck, before entering such forming of the mouth and neck, the coating resin layer crystallized by the drawing and ironing processes up to that time By making the thermoplastic resin amorphous again, it is necessary to further enhance the adhesiveness between the metal surface and the resin layer.

However, no matter what type of can body is manufactured, by providing a step for amorphization, it is necessary to install a heating device for that purpose in the middle of the manufacturing line. In order to improve workability, the lubricant such as wax applied from above the coating resin layer is volatilized and removed by heating, and the two steps of the degreasing / washing step and the subsequent drying step are one step. By reducing the number of equipment and simplifying the production line,
A new device for amorphization adds equipment again and makes the production line longer and more complicated, while the can body must be heated (and quenched) in the process for amorphization. As a result, the consumption of heat energy is increased and the production cost is increased.

[0010] Such a process for amorphization is carried out by using a heating device already installed in a production line as a lubricant removing process by heating or a drying (baking) process after printing and painting. It can be considered that the heating is performed together with such another heating step. However, the temperature of the empty can for making the thermoplastic resin layer amorphous (above the melting point of the film, approximately 280 ° C.)
(Before and after) is an empty can temperature (220
℃) and the temperature of the empty can at the time of drying and baking after printing and painting (around 230 ℃). Also, for example, by performing volatilization of the lubricant at a temperature higher than the appropriate temperature, the lubricant is carbonized and the can body is soiled,
By performing drying and baking after printing and painting at a temperature higher than the appropriate temperature, discoloration may occur in the can body, while if the amorphous state of the thermoplastic resin layer is performed at a temperature lower than the appropriate temperature, it can not be made amorphous Such a problem will occur.

An object of the present invention is to solve the above-mentioned problems, and more specifically, a production line for producing a can from a thin metal sheet covered with a crystalline thermoplastic resin layer. On the other hand, when installing a device for amorphizing the thermoplastic resin layer of the can body in the middle, the production line is simplified by suppressing an increase in the number of facilities, and the thermal energy consumed in the production line is reduced. It is an object of the present invention to reduce the consumption amount of as much as possible.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a method for manufacturing a can body from a metal sheet covered with a crystalline thermoplastic resin layer. About the oven device for heating the can body to be installed,
The inside of the oven body is divided into a plurality of heating zones having different temperatures along the traveling direction of the can body conveying conveyor passing through the inside of the oven body, and one of the plurality of heating zones in the oven body is replaced with a can body. As a heating zone for amorphizing the thermoplastic resin layer covering the metal surface, and other heating zones, for other heating steps required in the can-making process other than the amorphization The zone is characterized by the following.

According to the above-mentioned oven apparatus for can making, the lubricant is volatilized and removed at an appropriate temperature by one oven apparatus installed in the middle of the production line, or
Increasing the number of production line equipment, because the can body after printing and painting can be dried and baked at an appropriate temperature, and the thermoplastic resin layer covering the metal surface of the can body can be surely made amorphous. The process for the amorphization can be performed without any problem, and the use of the heat energy in the two heating processes can be efficiently performed by one apparatus, and the heat energy consumption in the production line can be reduced. Can be suppressed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the oven apparatus for cans of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an appearance of the oven apparatus for a can according to the present invention, FIG. 2 shows a gas reflux path in the apparatus, and FIG. 3 shows the inside of an oven body of the apparatus. 4 shows the structure of an endless belt conveyor passing through the oven body, FIG. 5 shows a state in which gas flows inside a can placed on the endless belt conveyor, and FIG. 7 shows a heat pattern of the can body when passing through each zone of FIG. 7, and FIG. 7 shows an example of a can making process using an oven apparatus.

As shown in FIG. 1, the oven apparatus 1 according to the present embodiment moves an oven body (heating furnace) 2 and a cooling chamber 3 along an endless belt conveyor 4 for continuously transporting can bodies. The endless belt conveyor 4 is provided continuously in a tunnel shape so as to surround the endless belt conveyor 4. As shown in FIG. 2, the inside of the oven body 2 has three different temperatures along the traveling direction of the endless belt conveyor 4. Heating zones 2a, 2b,
2c, a temperature controller 5 is provided in the oven main body 2 to make the temperature of each heating zone different and individual.

In the oven apparatus 1, for example, in a can making process as shown in FIG. 7, a high-temperature volatile lubricant applied to the can body from above the thermoplastic resin layer is volatilized by heating and removed. Is used for heating the can body in a lubricant removing step (or a drying step for heating and drying the can body after being subjected to printing and painting). As an example of an object to be used by the oven apparatus 1, a can-making process shown in FIG. 7 is performed in a bottle-type two-piece can (a bottom lid is attached to a lower end of a body of a can body in which a mouth, a neck, a shoulder, and a body are integrally formed). To form a two-member can except for the cap).

That is, in the can making process shown in FIG. 7, an amorphous thermoplastic resin layer is formed on both sides of a thin metal plate, and a high-temperature volatile lubricant is applied thereon. First, in a cup forming process, using a metal sheet as a material,
After blanking the coated metal sheet into a disk shape and drawing it into a cup shape, in the next can body forming step,
The cup is subjected to redrawing or ironing at least once or more to form a cylindrical can body having a small diameter and a reduced thickness.

Next, in a top dome forming step, drawing is performed a plurality of times on the can bottom side of the cylindrical can body having a bottom to form a shoulder portion and an unopened mouth and neck portion. In the removing step, the lubricant is volatilized by heating from at least the outer surface of the can body in which the mouth and neck is not opened and the lower end of the body is opened, and removed in the next trimming step, the body opposite to the mouth and neck is removed. After trimming the opening end side of the part to make the can body a predetermined length,
Send out for printing and painting processes.

Then, in a printing / painting step, a desired design (characters, decorative patterns, etc.) is printed on the cylindrical body of the can body, and a top coat is applied thereon, followed by a subsequent drying step. After the printing ink layer and the top coat layer are sufficiently dried (baked) by heating, in the next screw and curl forming step, first, the front end closed portion of the unopened mouth and neck portion is trimmed to form the mouth and neck portion. After opening the opening, the opening end is formed into an annular curl portion by external winding, a screw for cap screwing is formed on the cylindrical peripheral wall, and tamper evidence (Pilfarproof) is provided below the screw forming portion. A) forming a bead portion for fixing the breaking ring of the cap with the mechanism;

Next, in a neck / flange forming step, neck-in processing and flange processing are sequentially performed on the lower end opening end of the body opposite to the mouth and neck, and then a bottom cover winding step (not shown) is performed. , The bottom lid of another member made of a sheet metal material is integrally fixed to the flange formed at the lower end opening of the body of the can by a double seaming method using a seamer (can lid winding machine) As a result, a bottle-type two-piece can is manufactured.

The coated metal sheet used as a material for the above-mentioned can body is made of a metal sheet for cans such as an aluminum alloy sheet or a surface-treated steel sheet. The thickness obtained by laminating a protective coating layer of a thermoplastic resin is 0.1 to 0.4.
mm coated metal sheet, suitable polyester resins include copolymers of ethylene terephthalate and ethylene isophthalate, PET and PBT, and also mixtures of these resins with other homopolymers or copolymers. it can.

As a specific example of such a metal sheet coated by laminating a thermoplastic resin, a thickness of 0.31
For a 5mm 3004H191 aluminum alloy plate,
As a protective coating layer of a crystalline polyester resin, a mixed resin (PBT: PE) of a polybutylene terephthalate resin (PBT) and a polyethylene terephthalate resin (PET)
T = 60: 40). A coated metal sheet is used in which a film having a thickness of 20 μm is laminated on the inner surface side and 20 μm on the outer surface side.

The method of laminating the thermoplastic resin layer on the thin metal plate includes a method of directly bonding a thermoplastic resin film, which has been previously formed into a film, to the metal surface of the thin metal plate, and a method of laminating the thermoplastic resin film melted from a T-die. A method in which a thermoplastic resin is extruded onto a preheated metal thin plate and directly bonded, or a thermoplastic resin film that has been formed into a film in advance through an adhesive primer layer or a curable adhesive layer or a thermoplastic resin layer having good thermal adhesiveness. And heat bonding to the metal surface of a thin metal plate. After the thermoplastic resin film thermally bonded in this laminating process is once melted and rapidly cooled (for example, by passing it through water) to make it amorphous, so that the subsequent processability and adhesiveness are good. Becomes

The lubricant applied over the thermoplastic resin layer laminated in this way has thermal volatility, is excellent in press moldability and flavor retention, and has no problem in food hygiene. For example, normal butyl stearate, liquid paraffin, petrolatum,
Polyethylene wax, edible oil, palm oil, synthetic paraffin and the like are used. By using a high-temperature volatile lubricant that can be volatilized and removed by heating, a large amount of water is not required when removing the lubricant, and the degreasing / washing process and subsequent drying are performed. The lubricant can be removed from the can with only one heating step without the need for two steps.

By the way, the bottle type 2 as described above
In the can manufacturing process for manufacturing piece cans, the lubricant removal process between the top dome forming process and the trimming process (the lubricant must be removed at this stage so as not to interfere with printing and painting) Is performed by heating, but in such a heating, a lubricant removing step, or a drying step by heating after printing or painting, or in both steps,
At the same time, the thermoplastic resin layer covering the metal surface of the can body is made amorphous (reduced in crystallinity).

The oven apparatus 1 of the present embodiment is used in such a lubricant removing step by heating. This one oven apparatus 1 performs the volatilization and removal of the lubricant by heating, and furthermore, Although the original coated metal sheet material is in an amorphous state, the thermoplastic resin layer crystallized by the subsequent cup molding, can body molding, and top dome molding becomes amorphous again at this stage. Thus, the thermoplastic resin layer is heated and then rapidly cooled.

The oven body 2 through which the cans pass by the endless belt conveyor 4 so that the volatilization of the lubricant and the amorphization of the thermoplastic resin layer can be carried out without any problem by one oven device 1. As shown in FIG. 2, the inside is divided into three heating zones in which the temperatures of the cam-up zone 2a, the keeping zone 2b, and the amorphous zone 2c are different from the entrance side to the exit side along the transport direction of the can body. The interior of the cooling chamber 3 following the oven body 2 is used as a cooling zone, and the lubricant is volatilized and removed in the cam-up zone 2a and the keeping zone 2b, and the thermoplastic zone is formed in the amorphous zone 2c and the cooling zone (cooling chamber 3). The resin layer is made amorphous.

That is, since the volatilization temperature of the lubricant is generally lower than the amorphization temperature (melting temperature) of the thermoplastic resin layer, the temperature and time for volatilization of the lubricant are first set inside the oven body 2. Heating zones that can be taken are provided on the upstream side in the transport direction of the can body as a cam-up zone 2a and a keeping zone 2b.
Is a part for preheating the can body for the next amorphization step at the same time as the volatilization of the lubricant, and the can body from which the lubricant has been volatilized and removed in the heating zones 2a and 2b has the temperature. Without dropping, the melting temperature of the thermoplastic resin is set to be higher in the next amorphous zone 2c, and the thermoplastic resin layer covering the can body is melted for a moment, then immediately in the cooling zone (cooling chamber 3) at room temperature. After being quenched, the thermoplastic resin layer is in an amorphous state.

For this purpose, in the oven apparatus 1, the inlet and outlet of the oven body 2 (the oven body 2 and the cooling chamber 3
Is separated by an air curtain by hot air so that the can body conveyed by the endless belt conveyor 4 can freely pass therethrough and the heat inside the oven body 2 does not escape outside. For each of the cam-up zone 2a, the keeping zone 2b and the amorphous zone 2c in the main body 2, a separate burner (not shown) and a blower 6 are provided for each zone by a separate temperature control unit 5.
Are provided, so that each of the heating zones 2a, 2b, and 2c can maintain different predetermined temperatures inside one oven main body 2.

Specifically, in order to raise the temperature of the can body passing through the heating zone in 10 seconds from room temperature to near the volatilization temperature of the lubricant, the ambient temperature of the cam-up zone 2a is set to 300 ° C. And keeping zone 2b
Sets the ambient temperature to 220 ° C. in order to keep the temperature of the can body passing through the heating zone in 10 seconds at the volatilization temperature of the lubricant, and the amorphous zone 2c passes through the heating zone in 15 seconds. In order to raise the temperature of the can body to be heated to the melting temperature of the thermoplastic resin layer (about 270 ° C. or higher), the ambient temperature is set to 310 ° C.

Then, in the cooling zone (cooling chamber 3) following the oven main body 2, while passing through the zone in 15 seconds, air at normal temperature is blown from above to form a thermoplastic zone in the amorphous zone 2c of the oven main body 2. After the temperature of the resin layer reaches the melting point, the can body is rapidly cooled so that the temperature of the thermoplastic resin layer becomes equal to or lower than (the temperature at which the adhesion of the resin starts to stick −30 ° C.) or less within one minute. 4
The temperature of the can body that can be passed through each zone by transport by
The heat pattern is as shown in FIG.

Each heating zone 2a, 2 in the oven body 2
The hot air blown from the respective temperature controllers 5 by the individual burners and blowers for each of b and 2c is always blown downward from the upper side by the oven upper nozzle 21 as shown by the arrow in FIG. The endless belt conveyor 4 shown in FIG. 4 (A) is provided so that hot air can enter into the can body placed on the endless belt conveyor 4 with the opening end side down to improve heating efficiency. ) And (B)
As shown in FIG. 5, a concave groove 4a (for example, having a width of 9 mm and a depth of 0.3 to 1) is formed on the mounting surface side so as to provide a gap with the can body.
mm) extends in a direction orthogonal to the transport direction indicated by the arrow, and is assembled by piercing a plurality of (cylindrical pins) so as to alternate with a portion serving as a can body mounting surface as a whole conveyor. A predetermined interval (for example, 15 mm) is formed at the bottom of each groove 4a so that hot air flows smoothly downward.
〜30 mm) penetrate the plurality of holes 4b.

As described above, the endless belt conveyor 4 has a plurality of holes 4b, and the endless belt conveyor 4
The air below the can body mounting side of each heating zone 2a,
Vacuum pressure (for example, -20 mAq) which is communicated with the suction side of each blower 6 for blowing hot air of 2b and 2c.
, The air above the can body mounting side of the endless belt conveyor 4 is sucked downward from each hole 4b.

As a result, the can body placed on the endless belt conveyer 4 is pressed against the endless belt conveyer 4, thereby preventing the can body from overturning. As shown in FIG. 5, the hot air blown downward has a suction effect from the hole 4b below the can body, so that the hot air flowing down along the outer wall of the can body flows through the concave groove 4a. The hot air flows into the can body, rises along the inner wall of the can body, then reverses and descends near the center (axial center) of the can body and is sucked through the hole 4b. The body can also be heated from the inside.

As described above, by heating the can body from the inner and outer surfaces with the hot air, the efficiency of the heat treatment can be improved and the temperature of the can body can be increased in a short time. Further, in this embodiment, the can body is also cooled from the inner and outer surfaces in the cooling zone (cooling chamber 3) following the oven body 2, so that the can body can be cooled in a short time with good cooling efficiency.

The endless belt conveyor 4 passes through a high-temperature region in the oven body 2 which is a heating furnace, and furthermore, a thermoplastic resin layer of a can placed on the oven body 2 when passing through the oven body 2. Is in a molten state, it is necessary to use a material having heat resistance and releasability, and therefore, the base is made of glass fiber and has a Teflon-based surface belt. A belt or a chain, or a resin belt or a metal chain coated with Teflon (registered trademark) or fluorine is used.

In addition, with respect to such an endless belt conveyor 4, the can body is opened at the opening end side (the opening end side has a flange portion extending in the horizontal direction, but is omitted in each drawing). Is placed so that the temperature of the can body rises to the melting temperature of the thermoplastic resin layer in the amorphous zone as shown in FIG. May fall from the can body to the endless belt conveyor 4 that is in contact with the ground, but if it is the open end side that is cut off in the subsequent trimming process, the quality of the can body is adversely affected. Because it will not be given.

Each heating zone in the oven body 2 is sprayed downward from above to form an endless belt conveyor 4.
As shown in FIG. 2, most of the hot air that has flowed below the can body mounting surface is sent to the temperature control unit 5 of each of the heating zones 2a, 2b, and 2c by the suction action of each blower 6. It is circulated so as to be returned. At that time, the temperature of the returned air is detected by the temperature control unit 5 for each heating zone and the combustion of the burner is controlled, so that the temperature of each heating zone is set to a predetermined value. Temperature can be maintained. In addition,
Although not shown, the air returned to the temperature control unit 5 passes through a catalytic filter or the like on the way to remove the lubricant contained therein.

On the other hand, a part (about 10%) of the hot air which has flowed to below the endless belt conveyor 4 is sucked from below from the oven main body 2 and exhaust gas treatment device ( In the exhaust gas treatment device 7, the air from which the lubricant has been removed by a catalytic filter or the like in front of the combustion section is further raised to a high temperature in the combustion section. After reducing the amount of carbon contained in the recovered air by burning, a part of it is released into the atmosphere as treated exhaust gas,
In that state, fresh air is added from the atmosphere and mixed, and the air is returned to the oven device 1 again.

According to the can-making oven apparatus 1 of the present embodiment used as described above, in the can body production line, the amorphizing step and the lubricant removing step are continuously performed by one apparatus using one apparatus. By doing so, it is possible to reduce the size of the equipment and shorten and simplify the production line, as compared with a case where dedicated devices are individually provided for each process. In addition to reducing the equipment costs, the two heating steps are performed in a single device, making it possible to effectively use the heat energy. Can be suppressed.

Further, the can body to be manufactured can be efficiently manufactured by ending the heat treatment in the two heating steps in a short time (especially, rapidly cooling the can body heated in the amorphizing step). In this case, the heat history of the can can be greatly reduced, and the discoloration of the thermoplastic resin layer and the like due to the long-time heat history can be prevented, so that the quality of the can can be stabilized.

The volatile temperature of the lubricant (around 220 ° C.)
And the temperature at which the thermoplastic resin layer becomes amorphous (around 280 ° C)
If the lubricant removal step and the amorphization step are performed by a single apparatus, for example, when the volatilization of the lubricant is performed at a temperature higher than an appropriate temperature, the lubricant is carbonized. If the can body is soiled, and the thermoplastic resin layer is made amorphous at a lower temperature than the appropriate temperature, there arises a problem that the thermoplastic resin layer cannot be made amorphous. Then, both steps can be appropriately performed without any problem.

Further, in the oven apparatus 1 of the present embodiment, the recovered air is burned at a high temperature as a means for adding new air to the air recovered from the oven main body 2 and returning the air to the oven main body 2. By installing the exhaust gas treatment device 7 that reduces the amount of carbon contained in the air, it is possible to prevent the air from being polluted by the exhaust gas discharged from the oven device 1 into the atmosphere. The burned heated air is supplied to the oven body 2
, The heating in the oven main body 2 can be efficiently performed.

While the embodiment of the can-making oven apparatus of the present invention has been described above, the present invention is not limited to the above-described embodiment. The present invention is not limited to an apparatus for performing the amorphizing step together with the removing step, but may be implemented as an apparatus for performing the amorphizing step together with the drying (baking) step after printing and painting. The present invention is not limited to the apparatus for use in the bottle-making process of bottle-type two-piece cans as shown in the embodiment of the present invention, but includes a normal two-piece can (body portion) manufactured from a metal plate coated with a crystalline thermoplastic resin Apparatus for use in the can-making process of a can body (a one-piece can body having a body and bottom integrally formed) for a can body having a can lid wound and fixed to a can body having a body and a bottom integrally formed. It is also possible to implement as Regarding the specific structure of each part of the apparatus itself, for example, the direction of the groove of the belt conveyor may be set to the same direction as the transport direction of the can body, or a pond-shaped groove at a predetermined interval may be appropriately designed. Needless to say, it can be changed.

[0045]

According to the oven apparatus for a can of the present invention as described above, the thermoplastic resin layer covering the metal surface of the can body is made amorphous by one apparatus installed in the middle of the production line. Quality process, and
Other heating steps, such as removing the lubricant by heating and drying the can after printing and painting, can be performed at an appropriate temperature, compared to the case where separate equipment is provided for each step. , The equipment can be reduced in size, the production line can be shortened and simplified, and the heat energy can be effectively used by performing two heating steps in one apparatus, The consumption of heat energy in the production line can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of an embodiment of a can-making oven apparatus of the present invention.

FIG. 2 is an explanatory view showing a gas reflux path in the apparatus shown in FIG. 1;

FIG. 3 is a sectional front view partially showing a state of the inside of the oven main body of the apparatus shown in FIG.

FIG. 4 shows a partial structure of the endless belt conveyor passing through the oven body shown in FIG. 3 (A).
FIG. 3B is a top plan view, and FIG. 3B is a cross-sectional side view taken along line BB of FIG.

FIG. 5 is a cross-sectional front view showing a state in which gas flows inside a can placed on an endless belt conveyor in the oven main body shown in FIG. 3;

FIG. 6 is a graph showing a heat pattern of a can when passing through each zone of the apparatus shown in FIG. 2;

FIG. 7 is an explanatory view schematically showing an example of a can-making process in which the can-making oven device of the present invention is used.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Oven apparatus 2 Oven main body 2a Cam-up zone (heating zone inside oven main body) 2b Keeping zone (heating zone inside oven main body) 2c Amorphous zone (heating zone inside oven main body) 3 Cooling room (cooling zone) 4 Endless belt Conveyor (Conveyor for transporting cans) 5 Temperature controller 6 Blower 7 Exhaust gas treatment device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K050 AA01 AA05 BA01 BA12 CD16 CE01 CF06 CF16 CG08 DA07 4K056 AA14 BA02 BB01 CA01 CA15 DA02 DA33 DB03

Claims (4)

[Claims] An oven apparatus for heating a can body installed in a production line for manufacturing a can body from a metal sheet covered with a crystalline thermoplastic resin layer, wherein the oven device passes through the oven body. The inside of the oven body is divided into a plurality of heating zones having different temperatures along the traveling direction of the can body transporting conveyor, and one of the plurality of heating zones in the oven body is a metal surface of the can body. It becomes a heating zone for amorphizing the thermoplastic resin layer covering, and other heating zones are zones for other heating processes required in the can-making process in addition to the amorphization. An oven apparatus for can making, characterized in that: 2. A heating step other than the amorphization performed in the oven body is a step for volatilizing and removing a lubricant applied to the can body from above the thermoplastic resin layer. The can-making oven device according to claim 1, characterized in that: 3. The method according to claim 1, wherein the heating step other than the amorphization performed in the oven body is a step for drying and baking the can body after printing and coating. Oven for can making. 4. A means for evacuating a part of the air collected from the oven main body and adding new air to the oven main body and circulating the collected air, the collected air is burned at a high temperature and contained in the air. The oven apparatus for can making according to any one of claims 1 to 3, wherein the apparatus is installed as an exhaust gas treatment apparatus for reducing the amount of carbon.