JP4293330B2 - Canning oven equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to an oven device for can manufacturing that is installed to heat a can body in the middle of a can manufacturing line, and in particular, manufactures a can body from a metal thin plate coated with a crystalline thermoplastic resin layer. The present invention relates to an oven apparatus for amorphizing a thermoplastic resin layer that covers a metal surface of a can body in the middle of a production line.
[0002]
[Prior art]
For cans (can body parts) manufactured from aluminum or steel cans made from thin metal plates for cans (can body parts), the cans are made from thin metal plates that have been pre-coated with a thermoplastic resin layer as a protective coating. However, in the production of a can body from such a coated metal sheet, the resin layer that has been coated is obtained by repeatedly drawing and ironing the coated metal sheet. The crystalline thermoplastic resin crystallizes (the degree of crystallinity increases), its molding processability becomes poor, and the adhesion to metal decreases, so the trimming process (can In the process of cutting the open end of the body and aligning the height of the can body), flange processing, double winding processing, bead processing, etc., there is a problem that whitening or peeling of the coating resin layer is likely to occur. There is a risk of getting up.
[0003]
On the other hand, as a technique for solving such a problem, Japanese Patent Application Laid-Open No. 54-141886 discloses a material coated with a thermoplastic resin in the production of a coated metal container (side seamless can body). (Tm-5) ° C. to 300 ° C. [Tm: melting point of the resin] and then immediately (Ta-30) ° C. [Ta: the resin It is described that the crystallinity of the thermoplastic resin coated on the molded product (can body) is lowered (amorphized) by rapidly cooling to the pressure-sensitive adhesive start temperature].
[0004]
In addition, as a technique related to the amorphization of the coating resin layer in the production of such a coated metal container, JP-A-52-65579 discloses that when molding a metal coated with a thermoplastic polyester resin, As a method for adjusting the crystallinity of the resin layer before and after molding to a specified range for the purpose of improving molding processability and corrosion resistance, heat having a crystallinity in the range of 0 to 30% is used. Molding a coated metal formed by coating a plastic polyester resin layer, and then subjecting this molded product to dry heat or wet heat treatment in a temperature range higher than the glass transition temperature (Tg) of the resin layer and 5 ° C. lower than the melting point of the crystal. Describes that the crystallinity of the thermoplastic polyester resin layer is increased to a range of 5 to 50%.
[0005]
Furthermore, in Japanese Patent Laid-Open Nos. 48-49590 and 48-61584, a crystalline thermoplastic resin is thermally bonded to a metal plate so that the crystalline phase is 50 to 60% and is amorphous. In order to remove the distortion of the resin film layer after forming the coated metal plate with a phase of 50 to 40% coated with a resin film layer and forming the coated metal plate to form a container or container lid, It is described that the heat treatment is performed under a condition that maintains the balance between the crystal quality and the crystal quality.
[0006]
On the other hand, apart from each of the known techniques relating to the amorphization of the coated resin layer as described above or the maintenance of the balance between the amorphous and crystalline, the drawing and ironing are performed from the coated metal sheet coated with the resin layer. In the case of forming a can body by processing, in order to improve the workability at the time of forming, a high-temperature volatile lubricant such as wax is applied to the coated metal thin plate before molding from above the coated resin layer. By heating the molded can body to a temperature equal to or higher than the volatilization temperature of the lubricant, the can body does not require a large amount of water and does not require two steps of a degreasing / washing step and a drying step. It has been conventionally known that the lubricant is volatilized and removed (see, for example, JP-A-51-63787, JP-A-3-226319, etc.).
[0007]
[Problems to be solved by the invention]
By the way, when manufacturing a can body from a coated thin metal sheet coated with a crystalline thermoplastic resin through drawing or ironing, processing steps such as trimming process, neck-in processing and flange processing after forming the can body In order to surely prevent the coating resin layer from being whitened or peeled off, for example, as described in the above-mentioned JP-A No. 54-141886, a coated metal thin plate is obtained by drawing or ironing. After forming the can body, it is desirable to make the thermoplastic resin layer covering the can body amorphized again before entering a subsequent processing step such as a trimming step.
[0008]
In particular, bottle-shaped two-piece cans (cans consisting of two parts, except for the cap, where the neck and shoulders, shoulders, and body are integrally molded, and a separate bottom lid is fastened and secured to the bottom of the body. ) Can be formed from a coated metal sheet, after forming the can body from the metal sheet by drawing or ironing, Since it is necessary to further mold the screw, etc., the thermoplastic resin of the coating resin layer that has been crystallized by the drawing or ironing process so far before entering the mouth-and-neck molding process. It is necessary to further improve the adhesion between the metal surface and the resin layer by making the film amorphized again.
[0009]
However, no matter what type of can is manufactured, by providing a process for amorphization, it is necessary to install a heating device therefor in the middle of the production line. By removing the lubricant such as wax applied from the top of the coating resin layer by volatilization and removal by heating, the two steps of degreasing / washing step and subsequent drying step are made into one step. Even if the number of facilities is reduced and the production line is shortened and simplified, the equipment for amorphization is newly added to increase the number of facilities again and make the production line longer and complicated. Since the can body must be heated (and rapidly cooled) in the process, the consumption of heat energy is increased and the manufacturing cost is increased.
[0010]
Such a process for amorphization is carried out by using a heating apparatus already installed in the production line as a lubricant removing process by heating or a drying (baking) process after printing / painting. However, the temperature of the empty can for making the thermoplastic resin layer amorphous (above the melting point of the film, approximately 280 ° C.) is an empty can for volatilizing the lubricant. This is different from the temperature (around 220 ° C) and the empty can temperature (around 230 ° C) at the time of drying and baking after printing / painting. Even if it is going to be done, for example, the volatilization of the lubricant is performed at a temperature higher than the appropriate temperature, so that the lubricant is carbonized and the can body is soiled, or dry baking after printing / painting is performed at a temperature higher than the appropriate temperature. Can cause discoloration in the can On the other hand, so that the problems such as inability to amorphous when conducted at a temperature lower than the temperature suitable for amorphization of the thermoplastic resin layer occurs.
[0011]
The present invention is intended to solve the above problems, specifically, for a production line for producing a can body from a thin metal sheet coated with a crystalline thermoplastic resin layer, During installation, when installing a device to make the thermoplastic resin layer of the can body amorphous, the production line is simplified by suppressing the increase in facilities, and the amount of heat energy consumed in the production line It is an object to be able to suppress as much as possible.
[0012]
[Means for Solving the Problems]
  The present invention is an oven apparatus installed in the middle of a production line for producing a can body from a metal thin plate coated with a crystalline thermoplastic resin layer in order to solve the above-described problems, For transporting cans that pass through the oven bodyEndless beltThe oven body is divided into a plurality of heating zones having different temperatures along the direction of travel of the conveyor, and one of the heating zones in the oven body covers the metal surface of the can body. It becomes a heating zone for amorphizing the resin layer, and the other heating zone is a zone for other heating processes required in the can making process other than the amorphization described above.In the oven device for heating the can body, in each heating zone in the oven main body, hot air is blown from the upper side to the lower side, air is sucked below the transfer surface of the can body, and the opening end side of the can body In the endless belt conveyor that places and transports cans with the bottom facing down, a concave groove for forming a gap between the can bodies on the can body placing surface side, as a whole conveyor A plurality of holes are formed so as to alternate with the can mounting surface, and a plurality of holes are penetrated at predetermined intervals in the bottom of each groove.It is characterized by this.
[0013]
  According to the above can manufacturing oven device, the lubricant is volatilized and removed at an appropriate temperature by one oven device installed in the middle of the production line, or the can body after printing / painting is operated at the appropriate temperature. In addition to drying and baking, the thermoplastic resin layer covering the metal surface of the can can be amorphized without fail, so the process for amorphization can be carried out without increasing production line equipment. Moreover, the use of heat energy in the two heating steps can be efficiently performed by one apparatus, and the consumption amount of heat energy in the production line can be suppressed.Moreover, in each heating zone in the oven body, by blowing hot air from above to below, it is possible to prevent the can that is being transported from falling, and this hot air flows downward through the hole at the bottom of the groove. By being sucked, the can enters the inside of the can through the gap formed by the concave groove, and thus the can can be heated from the inside by the hot air.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a can-making oven device of the present invention will be described in detail based on the drawings. In addition, about one Embodiment of the oven apparatus for cans of this invention, FIG. 1 shows the external appearance of an apparatus, FIG. 2 shows the reflux path | route of the gas in an apparatus, FIG. 3 shows the inside of the oven main body of an apparatus. 4 shows the structure of an endless belt conveyor that passes through the oven body, FIG. 5 shows the state in which gas flows inside the can body placed on the endless belt conveyor, and FIG. FIG. 7 shows an example of a can-making process in which an oven apparatus is used.
[0015]
As shown in FIG. 1, the oven apparatus 1 of the present embodiment includes an oven belt (heating furnace) 2 and a cooling chamber 3 along an endless belt conveyor 4 for continuously conveying can bodies. As shown in FIG. 2, the interior of the oven body 2 is provided with three heating zones 2 a having different temperatures along the traveling direction of the endless belt conveyor 4. , 2b, 2c, and a temperature control unit 5 is attached to the oven body 2 for making the temperature of each heating zone different.
[0016]
For example, in the can making process as shown in FIG. 7, the oven apparatus 1 is a lubricant for volatilizing and removing the high-temperature volatile lubricant applied to the can body from above the thermoplastic resin layer by heating. It is a heating apparatus for can-making used for heating a can body in an agent removal process (or the drying process for drying the can body after printing and coating are performed by heating). As an example of the object of use of the oven apparatus 1, a can-making process shown in FIG. The can is made up of two members having a portion excluding the cap.
[0017]
That is, in the can making process shown in FIG. 7, a coated metal sheet in which a thermoplastic resin layer in an amorphized state is formed on both surfaces of a metal sheet, and a high-temperature volatile lubricant is applied thereon is formed. As a material, first, in a cup forming process, a blank obtained by punching a coated metal thin plate into a disk shape is drawn and formed into a cup shape, and then in the next can body forming process, at least once for this cup. The above-described redrawing process and ironing process are performed to form a cylindrical body with a bottom having a small diameter and a thin wall.
[0018]
Next, in the top dome forming step, the shoulder portion and the unopened mouth-and-neck portion are formed by performing drawing processing a plurality of times on the bottom side of the bottomed cylindrical can body, and then in the lubricant removing step. The lubricant is volatilized and removed by heating from at least the outer surface of the can body whose mouth and neck are not opened and the lower end of the body is opened, and in the next trimming process, the opening of the body opposite to the mouth and neck is opened. After trimming the end side to make the can body a predetermined length, it is sent out for the printing / painting process.
[0019]
Then, in the printing / painting process, the desired design (characters, decorative patterns, etc.) is printed on the cylindrical body of the can body, and after applying the top coat from the top, heating is performed in the next drying process. After the printing ink layer and topcoat layer are sufficiently dried (baked) by the following steps, in the next screw / curl molding process, first, the mouth and neck are opened by trimming the closed end of the mouth and neck that has not been opened. After that, the end of the opening is formed into an annular curled portion by external winding, a screw for cap screwing is formed on the cylindrical peripheral wall, and a tamper evidence (pill fur proof) mechanism is provided below the screw forming portion. A bead portion is formed for fixing the breaking ring of the cap.
[0020]
Next, in the neck and flange forming process, the neck-in process and the flange process are sequentially performed on the lower end opening end of the body part opposite to the mouth and neck part, and then in the bottom cover winding process (not shown) By fixing the bottom lid of another member made of a thin metal plate to the flange portion formed in the lower end opening of the body portion of the can body by the double winding method by (can lid winding machine) Manufactures bottle-type 2-piece cans.
[0021]
In addition, about the coating metal thin plate used as a material of the above can bodies, crystalline thermoplastics, such as a polyester resin and a polypropylene resin, on both surfaces of a metal thin plate for cans such as an aluminum alloy plate and a surface-treated steel plate. It is a coated metal thin plate having a thickness of 0.1 to 0.4 mm laminated with a protective coating layer of resin, and as a suitable polyester resin, a copolymer of ethylene terephthalate and ethylene isophthalate, PET or PBT, Mention may be made of mixtures of these resins with other homopolymers or copolymers.
[0022]
As a specific example of the coated metal thin plate by lamination of such a thermoplastic resin, a polybutylene terephthalate resin (PBT) is used as a protective coating layer of a crystalline polyester resin on a 3004H191 aluminum alloy plate having a thickness of 0.315 mm. Use a coated metal sheet that is a laminate of a mixed resin (PBT: PET = 60: 40) film of polyethylene terephthalate resin (PET) with a thickness of 20 μm on the inner surface side and a thickness of 20 μm on the outer surface side. ing.
[0023]
Regarding the method of laminating the thermoplastic resin layer to the metal thin plate, in addition to the method of directly bonding the thermoplastic resin film formed in advance to the metal surface of the metal thin plate, a thermoplastic resin melted from the T die is used. A method of directly extruding onto a preheated metal thin plate and directly bonding it, or a metal thin plate via a pre-formed thermoplastic resin film through an adhesive primer layer, a curable adhesive layer, or a thermoplastic resin layer with good thermal adhesion There is a method of thermally bonding to the metal surface. After the thermoplastic resin film heat-bonded in this laminating process is once melted (for example, by passing it through water), it is rapidly cooled to become amorphous, so that the subsequent processability and adhesiveness are good It becomes.
[0024]
Moreover, the lubricant applied from above the laminated thermoplastic resin layer is required to have heat volatility, excellent press moldability and flavor retention, and 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 removed by volatilization by heating, a large amount of water is not required when removing the lubricant, and a degreasing / cleaning step and subsequent drying are performed. The lubricant can be removed from the can body by only one heating step without requiring two steps.
[0025]
By the way, in the can manufacturing process for manufacturing the bottle type two-piece can as described above, the lubricant removing process between the top dome molding process and the trimming process (so that the lubricant does not become an obstacle to printing and painting at this stage) In the process of removing the lubricant by heating, the drying process by heating after printing / painting, or both processes, the metal of the can is simultaneously used. The thermoplastic resin layer covering the surface is amorphized (lowering the crystallinity).
[0026]
The oven device 1 according to the present embodiment is used in such a lubricant removal step by heating, and by this one oven device 1, the lubricant is volatilized and removed by heating. Although the metal sheet material is in an amorphized state, the thermoplastic resin layer crystallized by the subsequent cup molding, can body molding, and top dome molding is heated so as to be amorphized again at this stage. The plastic resin layer is heated and then rapidly cooled.
[0027]
Thus, the inside of the oven body 2 through which the can body passes by the endless belt conveyor 4 is removed so that the evaporation of the lubricant and the amorphization of the thermoplastic resin layer can be performed without any problem by one oven apparatus 1. As shown in FIG. 2, the cam-up zone 2a, the keeping zone 2b, and the amorphous zone 2c are divided into three heating zones having different temperatures from the inlet side to the outlet side along the conveying direction of the can body. The inside of the cooling chamber 3 following the main 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. Amorphization is performed.
[0028]
That is, since the volatilization temperature of the lubricant is generally lower than the amorphization temperature (melting temperature) of the thermoplastic resin layer, the heating zone in which the temperature and time for volatilization of the lubricant can be first taken inside the oven body 2. As a cam-up zone 2a and a keeping zone 2b on the upstream side in the conveying direction of the can. Each heating zone 2a, 2b is directed to the next amorphization step simultaneously with the volatilization of the lubricant. The can body is a part for preheating the can body, and the can body from which the lubricant has been volatilized and removed in the heating zones 2a and 2b, the melting temperature of the thermoplastic resin is further increased in the next amorphous zone 2c without lowering the temperature. The thermoplastic resin layer covering the can body is melted for a moment, and then immediately cooled in the cooling zone (cooling chamber 3) at room temperature to make the thermoplastic resin layer amorphous.
[0029]
Therefore, in the oven apparatus 1, the can body conveyed by the endless belt conveyor 4 can freely pass through the inlet and the outlet (between the oven body 2 and the cooling chamber 3) of the oven body 2, and the oven body 2 It is partitioned by hot air air curtain so that the heat inside does not escape to the outside, and individual temperature control units for the cam-up zone 2a, the keeping zone 2b, and the amorphous zone 2c in the oven body 2 5, by providing an individual burner (not shown) and a blower 6 for each zone, the heating zones 2 a, 2 b, and 2 c maintain different predetermined temperatures within one oven body 2. I can do it.
[0030]
Specifically, the cam-up zone 2a has an atmospheric temperature of 300 ° C. in order to raise the temperature of the can passing through the heating zone in 10 seconds from room temperature to near the volatilization temperature of the lubricant, In order to keep the temperature of the can passing through the heating zone in 10 seconds at the volatilization temperature of the lubricant in the keeping zone 2b, the atmospheric temperature is set to 220 ° C., and the amorphous zone 2c In order to raise the temperature of the can passing in seconds to the melting temperature of the thermoplastic resin layer (about 270 ° C. or higher), the ambient temperature is set to 310 ° C.
[0031]
Then, in the cooling zone (cooling chamber 3) following the oven body 2, air at normal temperature is blown from above while passing through the zone in 15 seconds, so that the thermoplastic resin layer is formed in the amorphous zone 2c of the oven body 2. After the temperature 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 (resin adhesion start temperature−30 ° C.) within 1 minute, and thereby transported by the endless belt conveyor 4. The temperature of the can passed through each zone is set to a heat pattern as shown in FIG.
[0032]
The hot air blown from each temperature control unit 5 by the individual burner and blower for each heating zone 2a, 2b, 2c in the oven body 2 is always supplied by the oven upper nozzle 21 as shown by the arrow in FIG. The endless belt is sprayed from the upper side to the lower side, so that the hot air enters the inside of the can placed on the endless belt conveyor 4 with the opening end side down, and the heating efficiency is improved. As shown in FIGS. 4A and 4B, the conveyor 4 has a groove 4a (for example, a width of 9 mm and a depth of 0.1 mm) that forms a gap with the can on the mounting surface side. 3 to 1 mm) extends in a direction perpendicular to the conveying direction indicated by the arrow, and the entire conveyor is assembled by being pierced with a plurality of cylindrical pins so as to be alternated with a portion to be a can body mounting surface. 1 for each conveyor part Each) with are formed, to flow smoothly hot air downward, predetermined intervals on the bottom of the groove portions 4a (e.g., a plurality of holes 4b in 15 to 30 mm) has been through.
[0033]
A plurality of holes 4b are formed in the endless belt conveyor 4 as described above, and the air below the can body mounting side of the endless belt conveyor 4 sends hot air from each heating zone 2a, 2b, 2c. Since the vacuum pressure (for example, −20 mAq) is in communication with the suction side of the blower 6, the air above the can body mounting side of the endless belt conveyor 4 is sucked downward from each hole 4 b. The Rukoto.
[0034]
As a result, the can body placed on the endless belt conveyor 4 is pressed against the endless belt conveyor 4 so that the can body can be prevented from overturning and sprayed downward from above. As shown in FIG. 5, the hot air that has been sucked through the hole 4b under the can body, the hot air that has flowed along the outer wall of the can body passes through the concave groove portion 4a. It enters the body, rises along the inner wall of the can body, and then reverses and descends near the center (axial center) of the can body and is sucked from the hole 4b. Can also be heated.
[0035]
Thus, by heating the can body from the inner and outer surfaces with hot air, the temperature of the can body can be raised in a short time with good heat treatment efficiency. Moreover, in this embodiment, since the can body is cooled from the inner and outer surfaces also in the cooling zone (cooling chamber 3) following the oven body 2, the can body can be cooled in a short time with good cooling efficiency.
[0036]
The endless belt conveyor 4 passes through a high temperature region in the oven body 2 that is a heating furnace, and the thermoplastic resin layer of the can placed when passing through the oven body 2 is in a molten state. Therefore, it is necessary to use a material having heat resistance and releasability. Therefore, a belt having a glass fiber and a Teflon-based surface, a belt or a chain of a high molecular polyethylene resin is used. Alternatively, a Teflon-coated or fluorine-coated resin belt, a metal chain, or the like is used.
[0037]
In addition, with respect to such an endless belt conveyor 4, the can body is on the opening end side (the opening end side has a flange portion extending in the horizontal direction, but is omitted in each drawing). As shown in FIG. 6, this is because the temperature of the can is raised to the melting temperature of the thermoplastic resin layer in the amorphous zone, so that the melted thermoplastic resin can be Even if it is in a state where it hangs down on the endless belt conveyor 4 that is in contact with the ground, if it is on the opening end side to be cut off in the subsequent trimming process, the can may be adversely affected in quality. Because there is no.
[0038]
As shown in FIG. 2, the hot air blown from the upper side to the lower side in each heating zone in the oven body 2 and flows downward from the can mounting surface of the endless belt conveyor 4 Most of the air is circulated by the suction action so as to be returned to the temperature control unit 5 of each heating zone 2a, 2b, 2c. At that time, the air returned by the temperature control unit 5 for each heating zone is circulated. By detecting the temperature and controlling the combustion of the burner, the temperature of each heating zone can be maintained at a predetermined temperature. Although not shown, the air returned to the temperature control unit 5 passes through a catalytic filter or the like in the middle to remove the lubricant contained therein.
[0039]
On the other hand, a part (about 10%) of the hot air that has flowed to the lower side of the endless belt conveyor 4 is sucked out from the lower part of the oven body 2 and installed in the vicinity of the oven device 1 (incinerator). ) The air that has been collected in the exhaust gas treatment device 7 and has been subjected to the removal of the lubricant by a catalytic filter or the like before the combustion section is further combusted at a high temperature in the combustion section. After reducing the amount of carbon contained in the recovered air, a part of it is released into the atmosphere as treated exhaust gas, and in that state, fresh air is added from the atmosphere and mixed again. The oven apparatus 1 is refluxed.
[0040]
According to the can manufacturing oven device 1 of the present embodiment used as described above, the amorphization process is continuously performed together with the lubricant removing process by one apparatus in the can manufacturing line. Compared to the case where dedicated devices are individually provided for each process, the equipment can be reduced, the production line can be shortened and simplified, and the equipment cost of the production line can be reduced. In addition, it is possible to effectively use heat energy by performing two heating processes in one device, and to reduce the operating cost by suppressing the consumption of heat energy in the production line. Can do.
[0041]
In addition, for the can body to be manufactured, the can body in the production line can be efficiently completed in a short time (especially by rapidly cooling the can body heated in the amorphization process). The thermal history of the can can be significantly reduced, and the quality of the can body can be stabilized by preventing the thermoplastic resin layer and the like from being discolored by a long-time thermal history.
[0042]
Since the volatilization temperature of the lubricant (around 220 ° C.) and the temperature at which the thermoplastic resin layer is made amorphous (around 280 ° C.) are different, the lubricant removing step and the amorphizing step are merely one. When the apparatus is used, for example, if the lubricant is volatilized at a temperature higher than the appropriate temperature, the lubricant carbonizes and the can body is soiled, and the thermoplastic resin layer is made amorphous at the appropriate temperature. If it is performed at a lower temperature, there will be a problem that it cannot be amorphized. However, in the oven device 1 of this embodiment, both steps can be appropriately performed without problems.
[0043]
Furthermore, in the oven apparatus 1 of the present embodiment, as a means for adding fresh air to the air collected from the oven body 2 and refluxing the oven body 2, the collected air is burned at a high temperature to be in the air. By installing the exhaust gas treatment device 7 that reduces the amount of carbon contained in the atmosphere, it is possible to prevent the atmosphere from being polluted by the exhaust gas discharged from the oven device 1 into the atmosphere, By heating the combusted heated air to the oven body 2, the oven body 2 can be efficiently heated.
[0044]
As mentioned above, although one Embodiment of the oven apparatus for cans of this invention was described, this invention is not restricted to said embodiment, For example, with a lubricant removal process as shown in said embodiment. The present invention is not limited to an apparatus for performing an amorphization process, and can also be implemented as an apparatus for performing an amorphization process together with a drying (baking) process after printing / painting. In addition to the device for use in the can-making process of the bottle-type two-piece can as shown in Fig. 1, a normal two-piece can (made to the body and the bottom) manufactured from a metal plate coated with a crystalline thermoplastic resin. It is implemented as an apparatus for use in a can manufacturing process of a can body (a one-piece can body in which a body portion and a bottom portion are integrally formed) for a can body formed by integrally fastening a can lid to a integrally formed can body. It is also possible for the device itself Regarding the specific structure of the part, for example, the direction of the grooved portion of the belt conveyor can be the same as the conveying direction of the can body, or the shape can be changed as appropriate, such as a pond-shaped grooved portion at a predetermined interval. Needless to say.
[0045]
【The invention's effect】
  According to the oven device for can making of the present invention as described above, the step of amorphizing the thermoplastic resin layer covering the metal surface of the can body by one device installed in the middle of the production line. It can be performed reliably, and other heating processes such as removal of lubricants by heating and drying of cans after printing and painting can be performed at appropriate temperatures, so each device can be used for each process. Compared to the case where it is provided individually, the equipment can be reduced in size, the production line can be shortened and simplified, and the heat energy is effectively obtained by performing two heating processes in one apparatus. Therefore, it is possible to suppress the consumption of heat energy in the production line.Further, in each heating zone in the oven body, the can body can be prevented from falling by the hot air to be blown, and the can body can also be heated from the inside by putting the hot air inside the can body.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an appearance of an embodiment of a can-making oven device of the present invention.
FIG. 2 is an explanatory diagram showing a gas reflux path in the apparatus shown in FIG.
3 is a cross-sectional front view partially showing the inside of the oven main body of the apparatus shown in FIG. 1 as viewed from the direction in which the can body is conveyed.
4A is a top plan view partially showing the structure of the endless belt conveyor passing through the oven main body shown in FIG. 3, and FIG. 4B is a sectional side view taken along line BB in FIG. Figure.
5 is a cross-sectional front view showing a state in which gas flows inside a can body 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 the 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 apparatus of the present invention is used.
[Explanation of symbols]
1 Oven device
2 Oven body
2a Come-up zone (heating zone in the oven body)
2b Keeping zone (heating zone in the oven body)
2c Amorphous zone (heating zone in the oven body)
3 Cooling chamber (cooling zone)
4 Endless belt conveyor (conveyor for cans)
5 Temperature controller
6 Blower
7 Exhaust gas treatment equipment

Claims (4)

An oven apparatus installed in the middle of a production line for producing a can body from a thin metal sheet coated with a crystalline thermoplastic resin layer, wherein the endless belt conveyor for conveying the can body passing through the inside of the oven body A thermoplastic resin layer in which the inside of the oven body is divided into a plurality of heating zones having different temperatures along the traveling direction, and one of the plurality of heating zones in the oven body covers the metal surface of the can body. For heating the can body, which is a heating zone for amorphizing, and other heating zones are zones for other heating processes required in the can manufacturing process besides the amorphization described above In the oven device of
In each heating zone in the oven body, hot air is blown from the upper side to the lower side, air is sucked below the transfer surface of the can body, and the opening end side of the can body is turned down In the endless belt conveyor for placing and transporting the can body, a concave groove portion for forming a gap with the can body is formed on the can body placing surface side. A can-making oven device , wherein a plurality of holes are alternately formed, and a plurality of holes are penetrated at predetermined intervals in the bottom of each concave groove . Cooling for rapidly cooling the can body being transported by spraying room-temperature air downward from the heating zone for amorphizing the thermoplastic resin layer covering the metal surface of the can body The canning oven device according to claim 1, wherein a cooling chamber having a zone is arranged . The heating process other than the amorphization performed in the oven body is a process for volatilizing and removing the lubricant applied to the can body from above the thermoplastic resin layer. The oven device for can making according to 1 or 2 . Another heating step other than the amorphization performed in an oven body, a can-according to claim 1 or 2, characterized in that the can body after printing, painting is a process for drying baking Oven equipment.

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