KR101008503B1 - Can container with screw - Google Patents

Abstract

Opening torque of the cap of the can container with which the joining step part of the joining can body is formed in the screw part is reduced.

Cylindrical container body part having overlapping junction part 16 in which the step part 15 was formed in the side surface, and the container part which a thread and a curl part are formed in the open end of the container body part. And a cap having a bottom lid wound around the bottom of the body portion and having a resin sealing liner formed on the inner surface side of the top plate portion. A can container with a screw, which is formed in a skirt portion of a cap in accordance with the screw thread, and whose cap is wound around the container bend, wherein the screw thread overlaps the joint 16 with the stepped portion. The cap 7 is formed in the direction in which the cap 7 is opened from the upper side to the lower side.

Description

Can container with screw

The present invention covers the cap of the container with a cap in which a sealing liner made of resin is attached to the inner surface side of a top plate of a metal shell, and rolls the cap by roll-on molding. In particular, a canister with a screw attached to a container part, particularly, has a joint portion in which a metal plate is polymerized on the side of the body of the can container, and a bottom lid is wound around the bottom of the body. A canister with a screw is provided.

2. Description of the Related Art Conventionally, packaging containers are known, such as food containers, such as glass bottles, which have large openings for their contents and which have a re-seal function. This kind of packaging container is used to fill the contents of instant coffee, cream powder, jam, corn soup, sauce, fruit juice with flesh, since it is easy to withdraw the contents or transfer the contents to a separate container. have. In addition, when a beverage such as coffee, black tea or green tea is used as the contents, the aroma can be enjoyed when the lid is opened, and thus a container with a wide mouth is widely used.

Recently, a sealing liner made of a resin is provided on the inner surface side of the top plate portion of the shell made of a metal cap, and the cap can be screwed and rolled on by forming the cap on the container portion. It is distributed and sold. The cap and the container body are all made of metal, and are excellent in light shielding properties and air permeability to the contents, as well as the convenience of being resealed and transported, and not as heavy as a glass bottle. The weight and the like of PET bottles are highly appreciated, and have been shipped to the market a lot.

Moreover, while such a screw container can be equipped with various sizes and various sizes of container bends are prepared, a new type of packaging container utilizing the wide advantages of the container bends as described above is, for example, Japan. A can container with a screw of a type with a wide opening is known, as described in Japanese Patent Laid-Open No. 2003-321039.

Usually, when attaching a cap to a seal can container, a cap (sometimes referred to as a cap shell) that has not been cut into a skirt portion (or a cylindrical portion) coming down from the outer periphery of the top plate portion is covered with a container bent portion, A screw groove (female thread) is formed so as to follow a screw thread (male thread) formed in the neck portion of the container sphere by pressing the screw forming roll from the outside of the skirt portion by a roll-on capping device known in the art. In addition, the cap shell is fixed-fastened and thus the cap is attached to the groove part. In the case of roll-on-molding such a metal cap, for sealing, the corner portion between the top plate portion and the skirt portion of the cap shell is deformed inward while the cap shell is covered with the container bent portion. By inserting the container bend into the liner, it is known that the sealing of the container bend by the liner is assured, for example, as described in Japanese Patent Laid-Open No. 2001-213417.

In addition, in a wide canal seal can having an internal diameter of 30 mm or more in the container sphere, the can body is uneven due to unevenness of the curl surface of the curl portion due to the shaping of the thread. It is also known in the art to form a pre-curl portion at the upper end of the upper surface, to form a screw thread, and then to form the curl portion again (for example, see Japanese Patent Laid-Open No. 2003-251425).

[Initiation of invention]

[Problem to Solve Invention]

By the way, in the slicing can with a wide opening described in Japanese Patent Laid-Open No. 2003-251425, the curl portion is formed after forming a pre-curl portion at the upper end of the can body and forming a screw thread (male screw). By forming, the opening torque could be made smaller by the amount where the variation in the height of the ceiling surface of the container was small. However, for example, in the case of a seal can with a wide entrance using a can body for a three-piece can having a junction on the side of the can body, such as a welding can body, it is required to be further opened.

That is, in the case where the cap is covered with the container bend and roll-on-molded, the skirt part of the cap shell is deformed so as to follow the screw thread (male screw) formed in the container bevel, so that the stepped portion of the joint is transferred to the cap. The trace of the stepped portion (hereinafter referred to as the "stepped trace") is formed in the screw groove (female thread) of the cap. And the step difference trace formed in the step part of a junction part and the screw groove of a cap is in the state facing each other, and a cap is attached to a container part. For this reason, when turning a cap and opening it, when the trace of the level | step difference of a cap exceeds the level of a junction part, one of the reasons which increases the opening torque which starts to turn a cap at the time of opening is a step trace of a cap and a step part of a junction part. It can be seen from the various experiments of the applicant.

Moreover, when the trace of the step difference of the cap is opened beyond the stepped portion of the joint, the coating film covering the edge portion of the joint is peeled off, or the cap inner surface coating is scraped off by the edge portion, resulting in resin residue. As a result, it has also been found that there is a problem that the resin residue adheres to the container bent portion and mixes in the contents, and there is a problem that the resin residue is swept into the seal portion to impair the sealability upon reopening.

This invention aims at solving the above-mentioned problem, Specifically, it is possible to improve the sealing property and openability of the container bend by a cap, and also to prevent generation | occurrence | production of resin waste at the time of opening, An object of the present invention is to provide a can container with a screw which prevents foreign matter from adhering to the container inlet.

[Means for solving the problem]

In order to achieve the above object, the invention of claim 1 includes a cylindrical container body having an overlapping joint with a stepped portion formed on its side, and a container bent in which a screw thread and a curl are formed at the open end of the container body. The bottom lid is wound around the bottom of the section, and the cap of the resin sealing liner is placed on the inner surface side of the top plate to cover the container section, so that the screw groove is formed in the skirt section of the cap in accordance with the thread. The can container with a screw which cap-sealed the cap WHEREIN: The said screw thread is formed in the direction which opens a cap toward the lower side from the upper side of the step part which overlapped with respect to the said junction part.

Moreover, this invention is a screw can container with which the at least inner surface side junction part of the said container trunk part is coat | covered with the water-retaining layer which stuck the thermoplastic resin film.

Moreover, in this invention, the part which coat | covers the said junction part among the said thermoplastic resin films is comprised by the tape-shaped resin film, The width | variety of the said tape-shaped resin film in the circumferential direction of the said trunk | drum is 7-15 mm. And the thickness of the tape-shaped resin film is set to 15 µm to 45 µm, and the tape-shaped resin film overlaps with the first layer and the first layer facing the bonding portion. And a second layer in contact with the contents on the inner surface side of the body portion, wherein the first layer has a melting point of 175 ° C to 230 ° C, and the second layer has a melting point of 200 ° C to 255 ° C, and 2 It is comprised by resin axially oriented, The melting point of resin which comprises the said 2nd layer is 15 degreeC-80 degreeC higher than the melting point of resin which comprises the said 1st layer, The thickness of the said 1st layer is the said tape shape Resin Film A candle container with a screw, characterized in that it is set to more than 70% of the thickness of the thickness.

And this invention sets the level | step difference of the step part of the said junction part to 0.07 mm or less, and the said container bend axis | shaft 15% or more with respect to a can trunk | drum diameter, and the top surface of the said container bend part It is a canned container with a screw, characterized in that the step of the stepped portion of the junction portion located in the portion is set to 0.05 mm or less.

[Effects of the Invention]

According to this invention, a screw thread is formed in the cylindrical container trunk part which has an overlap junction part in which the step part was formed in the side surface in the direction which a cap opens toward the said junction part from the upper side to the lower side. In other words, with respect to the stepped portion that is convex on the outside of the overlapping portion of the container body, the stepped portion that is formed on the cap is formed on the front side in the circumferential direction in which the cap is rotated to open. The screw thread is formed so that it is located. Therefore, at the time of opening, the trace of the step formed in the screw groove of the cap does not get caught in the stepped portion of the joining portion (overlapping portion), so that the cap can be turned, thereby improving the openability.

Moreover, at the time of opening, the generation of the resin residue which originates in the edge part of a step part is prevented, and the effect is that the screwed can container which prevented the adhesion of the foreign material to a container entrance is obtained.

In addition, according to the present invention, in addition to the above-described effect, even if excessive molding is performed on the container bend in order to reduce the step difference affecting the openability, that is, excessive molding such as molding of the screw portion or molding of the curl portion Even if it is carried out, the thermoplastic resin film which repairs the inner surface side of a junction part does not produce damage, such as a crack, peeling, or a fracture, and can be made favorable in corrosion resistance at this point.

And according to this invention, at least the inner surface of the junction part of the said container trunk part is coat | covered with the thermoplastic resin film, and the part which coats a junction part among the said thermoplastic resin films is comprised by the tape-shaped resin film, The said trunk While the width of the tape-shaped resin film in the negative circumferential direction is set to 7 mm to 15 mm, and the thickness of the tape-shaped resin film is set to 15 μm to 45 μm, the tape-shaped resin film is a bonded portion. It has a 1st layer which opposes, and the 2nd layer which overlaps with this 1st layer, and touches the content in the inner surface side of the said trunk | drum, The said 1st layer has melting | fusing point of 175 degreeC-230 degreeC, Melting | fusing point of the 2nd layer is 200 degreeC-255 degreeC, Moreover, melting | fusing point of resin which comprises the biaxially-oriented resin, and the melting point of resin which comprises the said 2nd layer comprises the said 1st layer It is 15 degreeC-80 degreeC higher than, and since the thickness of a said 1st layer is set to the thickness exceeding 70% of the thickness of the whole tape-shaped resin film, a 1st layer melts and it fully reaches to the edge part of the step part of a junction part. In addition to being able to coat | cover, since the 2nd layer whose melting | fusing point is higher than a 1st layer does not melt, biaxial orientation is maintained as it is and the corrosion resistance of the inner surface side of a junction part can be improved.

In addition, when the cap is opened, a screw thread is formed so as to rotate the cap in a direction from the upper side to the lower side of the stepped portion in the overlapping portion, so that in the curled portion of the outer winding where the upper end of the container is curled outward, The inner surface side is turned upside down to the outside. Therefore, the level of the joint at the top surface of the curl is reversed with respect to the direction of the level of the joint at the outer surface of the neck, and the level at the curl of the container is facing in the opening direction of the cap. Since the inner surface side joining portion of the trunk portion is covered with the tape-shaped resin film, the stepped portion is made smooth while keeping the step amount as small as possible, so that the stepped portion of the curl portion and the liner can be reduced.

As a result, even when the container bend is inserted into the liner to maintain good sealing between the container bend and the cap, the opening torque of the cap can be reduced to smoothly open the cap.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view showing a wide re-seal can with a roll-on cap as an example of the present invention.

It is a front view which shows the cap before roll-on shaping | molding, and the joining can body which did not wind up the bottom lid.

3 is a partial sectional view mainly showing a curl portion and a liner of the container bend.

Fig. 4 is a schematic diagram showing the opening direction of the junction portion of the container body and the cap, and is a partially enlarged sectional view showing the fitted state of the cap at the time of opening.

FIG. 5: is a schematic diagram which shows the junction part of a container trunk | drum and the opening direction of a cap, and is a partial sectional drawing which shows the fitting state of the junction part and cap in the middle of the resealing operation after opening.

FIG. 6A is a partially enlarged cross-sectional view showing a state where a curl portion of a container bent portion and a liner are fitted before roll-on molding, and (B) is a partially enlarged cross-sectional view showing a state after roll-on molding.

7 is a partial cross-sectional view showing a joint by welding.

BEST MODE FOR CARRYING OUT THE INVENTION [

EMBODIMENT OF THE INVENTION Hereinafter, one preferred embodiment of this invention is described based on drawing. As shown in Figs. 1 and 2, the metal resilient can (can body excluding the cap) 1 of the present embodiment is secured by winding a separate bottom lid 3 to the lower end of the joining can body 2. One configuration. That is, the container spherical part 5 is formed above the cylindrical trunk | drum 4, and the bottom lid 3 is fixed to the opening end part of the lower end of the can trunk | drum 2 by the winding body. In the container bend 5, a metal fillerproof cap 7 having a resin liner 6 is roll-on-molded by a conventionally known capping device. The screw groove 9 is formed in the cylindrical part in the skirt part 8 of (7), and is attached.

In addition, as shown in FIG. 3, the screw thread 10 is formed in the outer peripheral surface of the container part 5, and below the ring-shaped bead part (in concave groove and outer surface with respect to an inner surface). Convex jaw 11 is formed, and this ring-shaped bead portion 11 is formed by attaching a metal cap 7 to the container bend 5 by a conventionally known capping device. , A forming roll (not shown) of the capping device enters and beads the lower wall of the cap 7 (lower portion of the peeler proof band 12 formed on the lower end of the skirt portion 8 of the cap 7). By pushing and shaping the upper end of the portion 11, the cap 7 is fixed to the container sphere 5 in a state of a peeler proof.

The cap 7 of this embodiment consists of a metal shell 13 and a sealing liner 6 made of resin, and the shell 13 roughly covers the skirt portion 8 from the circumferential edge of the top plate portion 14. The liner 6 is formed in a cylindrical shape, and a liner 6 is attached to the inner surface side (lower surface side) of the top plate portion 14. The lower end of the skirt portion 8 of the cap 7 (i.e. the shell 13), i.e., the screw groove, in the state before being mounted by roll-on molding on the container portion 5 of the joining can body 2 is formed. The peeler proof band 12 is formed so that the bridge | bridging 12B formed between the horizontal slits 12A may be broken and isolate | separated from the edge part below the scheduled cylindrical part.

Although the material of the cap 7 (or the shell 13) is not specifically limited, For example, metal materials, such as an aluminum alloy plate in which the epoxy-phenol resin which disperse | distributed the olefin resin powder was apply | coated to the inner surface side. Is used. As the material of the liner 6, conventionally known resin materials such as blend materials of low density polyethylene and ethylene-propylene rubber-like copolymers, blend materials of polypropylene and styrene elastomers, and polyester elastomers are used. And the liner 6 is shape | molded by the well-known mold pressure shaping | molding method etc. which push the said resin material to the inner surface side of the top plate part 14 in a molten state, and mold-pressure.

On the other hand, the can body of the present embodiment is formed with a screw thread (male screw) 10 and a bead portion 11 at the neck portion of which the diameter of the open end of the cylindrical canned body 2 is reduced. Applicant's various experiments showed that the direction of the stepped portion 15 on the side surface of the substrate had a significant effect on the integrity.

Here, the junction can body 2 and the step part 15 are demonstrated. The joining can body 2 is constructed by cutting the above-described metal plate into the size of one can, forming it into a cylindrical shape, and welding by overlapping both ends of the metal plate slightly. The junction part 16 formed in this way is shown as an expanded sectional drawing in FIG. 4, Since the junction part 16 becomes thicker than another part, the step part 15 arises. And the step part 15 differs in the direction which becomes convex in the outer surface side and inner surface side of the junction can body 2, In the example shown in FIG. 4, the left part of FIG. 4 is convex outward on the outer surface side. On the inner surface side, on the contrary, the right side becomes a step | step which becomes convex toward an inner side.

In other words, when the cap 7 is rolled on the container bent portion 5 and roll-on-molded, the shell 13 covered by the container bent portion 5 is pressed against the thread 10 of the neck portion of the container bent portion by means of a screw forming roll. The stepped portion 15 of the joined portion in the neck portion formed by drawing-molding the joined can body 2 is transferred to the cap 7, and as a result, the stepped portion 15 of the joined can body 2 is formed. A step trace 17 is formed in the screw groove 9 of the cap 7. Then, the step trace 17 formed in the screw groove 9 of the cap 7 faces the step portion 15 in the joint 16 on the can body 2 side, so that the cap 7 It is attached to the container part 5. More specifically, the inclined surface on the stepped trace 17 on the inner surface side of the cap 7 and the inclined surface on the stepped portion 15 on the outer surface side of the joining portion 16 face each other or the cap The step trace 17 on the inner surface side in the screw groove 9 of (7) and the step part 15 on the outer surface side of the container bent portion 5 or the neck portion are engaged.

When the cap 7 is opened by turning the cap 7 in a direction to more actively or strongly engage the step trace 17 and the step portion 15, the step trace 17 of the cap 7 is joined to the joint 16. It was found that opening could not be started unless the stepped section 15 of the neck portion of the neck was over, and this resulted in a large opening torque when the cap 7 was started to turn.

In addition, when the cap 7 is opened, when the step trace 17 on the inner surface side of the cap 7 crosses the step portion 15 of the joining portion 16, the film on the edge of the step portion 15 is removed. The inner coating film of the cap 7 may be peeled off or peeled off by an edge, and the coating film (also referred to as the resin residue) may adhere to the container bend 5, resulting in poor sealing performance when re-opening, or mixing into the contents. It is also a cause that is not hygienic.

As a countermeasure, in the joint can body 2 of the present embodiment, the step trace 17 of the screw groove 9 in the cap 7 is the joint 16 in the neck portion of the can body 2. Even when the cap 7 is attached to the container bent portion 5 in a state facing the stepped portion 15 of the opening, the opening direction of the stepped portion 17 of the cap 7 and the junction portion 16 The cap 7 is opened by turning the cap 7 in the direction in which the step portion 15 is spaced apart. That is, the screw thread 10 formed in the neck part is lower than the upper side (the outer surface side of the can main body 1, or the outer side in the radial direction of the can main body 1) of the junction part 16 (overlapping part) (can main body). It is formed in the direction in which the cap 7 is opened toward the inner surface side of (1) or the radial direction inside of the can main body 1). Therefore, when opening the cap 7, the inner surface of the step trace 17 in the screw groove 9 (female thread) of the cap 7 is turned without being caught by the step 15 of the joint 16. It becomes possible.

Here, once the cap 7 is opened, the peeler proof band of the cap is separated, and the edge portion of the cap is opened so that the gap between the screw thread 10 and the screw groove 9, or the step, is to be sealed again. The gap C between the part 15 and the step trace 17 becomes larger than before opening, as shown in FIG. 5. Therefore, the step 15 and the step trace 17 are no longer a problem when resealing (when sealing).

On the other hand, in the curl part 18 formed in the edge part of the joining can body 2, when the curl part 18 is formed by winding outwardly, it is the joint part 16 in the top surface of the curl part 18. As shown in FIG. Since is reversed, the direction of the stepped portion 15 on the top surface of the curled portion 18 appears in the direction opposite to the direction of the stepped portion 15 of the neck portion. For this reason, it is necessary to make the step amount less than the step part 15 formed in the screw thread 10, and to prevent it from affecting when the celestial step part 15 starts to turn the cap 7 at the time of opening. Therefore, it is preferable to weld so that the step amount at the time of joining the can body 2 to a cylinder is extremely small, preferably 0.07 mm or less. Moreover, the container part 5 of the can body 2 welded in this way is reduced by 15% or more with respect to the diameter of the can body 2, and the step amount of the step part 15 of the neck part is compressed from the circumferential direction. It is desirable to reduce by

In the die neck molding method in which the container bend 5 has an axial diameter ratio of less than 15% with respect to the can body diameter, the degree of plastic working of the joint 16 is small, and it is expected to reduce the step amount of the joint 16. Can't.

As a cap for a seal can with a wide inlet, as shown in Fig. 6A, a cap having a large depression in the panel of the top plate portion 14 may be used in addition to the shape of the top plate portion having a substantially planar shape. In the case of attaching such a cap to the container bend, the axial diameter ratio of the container bevel is effective.

That is, when the curled part 18 is folded and folded and the curled part 18 is formed by pressing from the side, since the curl part 18 is formed long and thin vertically, the cap top plate part 14 The contact load between the curled portion 18 and the liner 6 due to the compression load to press the pressure tends to be smaller than that of the cross-sectional circular (released cross-section) curl, and the sealing property tends to be lowered. Therefore, in order to compensate for the contact load, as shown in FIG. 6 (B), in the state of pressing the top plate portion 14 of the cap shell 13, a remolding tool (not shown) is used. The corner portion 14a of the panel of the cap 7 is deformed to the outside using the), and the corner portion 7a of the cap 7 is deformed inwards, and the curl portion (c) is formed from both sides through the liner 6. Increasing the adhesion of the liner 6 with 18) in between. Even in such a case, when the container bent portion 5 is subjected to the shaft diameter machining at the shaft diameter, the stepped amount of the joint portion on the surface of the curl portion 18 in contact with the liner 6 can be 0.05 mm or less, and the integrity is improved. The impact on can be reduced.

The joining can body 2 mainly has both methods of adhesion and welding. In particular, in the case of a welding can by the welding method, the coating layer 19 formed on the steel sheet is as shown in Fig. 7. When manufacturing the joining can main body 2, the area | region used as the joining plan part of the both ends joined is formed leaving width 1.5mm-about 3.0mm. Since welding is performed in an unpainted state, in order to ensure corrosion resistance after welding, repair coating of this area is required. In the state where the step part 15 is formed in the junction part 16 not much, the cylindrical trunk | drum 4 is manufactured. In this way, the cylindrical can part 2 and the joined can body 2 in which the coating layer 19 was formed in the inner peripheral surface except the junction part 16 of this trunk part 4 are manufactured.

The non-maintenance bonded portion 16 on the inner surface side of the bonded can body 2 is covered with an inner repair resin. In FIG. 7, the width of the inner surface repair coating layer 20 in the circumferential direction of the trunk portion 4 is set within the range of 7 mm to 15 mm in order to improve the coating property and workability. This internal repair coating layer 20 can be formed by a single layer or a composite layer. As a method of forming the internal repair coating layer 20, there are a method of applying an inner coating and a method of applying a tape-shaped resin film.

As a coating material for repair coating, a curable synthetic resin such as polyester or phenol, in particular a thermosetting synthetic resin, is used. However, these thermosetting synthetic resins have a high hardness after melting and pasting the coating film, so that the coating film may be cracked or the film may be peeled off when the neck is formed at the opening end, the curl molding, and the press molding is formed by folding the curled portion. none. For this reason, the method of sticking a tape-shaped resin film is preferable in view of corrosion resistance.

In the case of supporting molding with a repair paint, it is conceivable to repair it thinly. However, if the thickness of the inner repair coating layer 20 is thin, it is difficult to completely repair the step 15 of the welding due to fluidity and the like, and improve the openability. In order to make it hard, after finishing processing which is excessive neck shaping | molding or curl shaping | molding is severe, there exists a possibility that a coating film may be damaged and corrosion resistance may become inadequate. On the other hand, by adhering the tape-shaped resin film of fixed thickness, the bad influence to corrosion resistance etc. can be suppressed little. Particularly, when curling the neck opening end, even in the case of excessive molding in which a curl is formed by winding the curled portion from the side to press the curled portion from the side in view of ensuring sealing and smoothness of the top surface of the curled portion, The film will not be scratched or peeled off to maintain corrosion resistance.

When sticking and repairing a tape-shaped resin film, after heating the temperature of the area | region which affixes the tape-shaped resin film in the inner surface of the trunk part 4 in the range of 170 degreeC-230 degreeC, a tape shape resin is applied to the area | region Compress the film. As a method of sticking a tape-shaped resin film, the tape-shaped resin film itself may be made heat-adhesive, and the adhesive layer of thermosetting resin may be provided with respect to a tape-shaped resin film. Examples of the tape-shaped resin film include polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin, copolymerized polyester resins made of copolymerization of polyethylene terephthalate and isophthalate acid, polypropylene resin, and polycarbonate. A tape-like resin film made of a single transparent thermoplastic polymer resin selected from resins, polystyrene resins, polyolefin resins, vinyl chloride resins, or the like, or a composite of the above resins is used. It is preferable to set the thickness of the tape-shaped resin film attached to the inner surface side of the trunk | drum 4 in the range of 15 micrometers-45 micrometers, in order to improve coating | coverability, workability, and post-processing property.

The tape-shaped resin film may be either non-stretched or stretched, but is preferably formed from a composite layer, in which case the first layer of the tape-shaped resin film faces the trunk portion 4 side. And a second layer overlapping the first layer and facing the inner side of the trunk portion 4. Further, the first layer is composed of a thermoplastic resin having a melting point of 175 ° C to 230 ° C, and the second layer has a melting point of 200 ° C to 255 ° C and a biaxially oriented thermoplastic resin. It is preferred to be configured.

The melting point of the thermoplastic resin constituting the second layer is 15 ° C to 80 ° C higher than the melting point of the thermoplastic resin constituting the first layer, and more preferably 20 ° C to 40 ° C. The material of the layer is selected. And the thickness of a 1st layer is set to the thickness over 70% with respect to the total thickness of a tape-shaped resin film. Here, after crimping | bonding this tape-shaped resin film to the bonding part 16, post-heating is performed at temperature higher than melting | fusing point of a 1st layer, and lower than melting | fusing point of a 2nd layer. As the thermoplastic resin used here, for example, polyethylene resin, modified polyethylene resin, polypropylene resin, modified polypropylene resin, and polyolefin resin can also be used, but as the inner surface coating layer 19, a polyester resin such as polyethylene terephthalate resin is used. When using, it is preferable to use polyester-based resin as a 1st layer from a viewpoint of adhesiveness of resin. In addition, the thickness of the inner surface repair coating layer 20 is set in the range of 15 micrometers-45 micrometers, More preferably, 18 micrometers-30 micrometers in consideration of corrosion resistance, workability, and workability.

Moreover, by making the thickness of a 1st layer into 70% or more of the total thickness of a tape-shaped resin film, it can coat | cover completely to the edge part of the step part 15 in the inner surface side of the bonding part 16, and is rusted. ) Can be reliably prevented. Moreover, it is preferable to coat the junction part 16 of an inner surface side with the tape-shaped repair film of 15 micrometers or more in thickness. As a result, the stepped amount on the surface of the curl can be further reduced, and the stepped amount is 0.05 mm or less, preferably 0.04 in a state where the stepped portion 15 of the joint 16 on the surface of the curled portion is covered with a tape-shaped resin film. It becomes possible to suppress it to mm or less, and can reduce the engagement resistance with the liner 6 at the time of cap opening.

However, when the tape-shaped resin film thickness which covers the inner surface side of the bonding part 16 is thinner than 15 micrometers, handling at the time of conveyance in the process of sticking to the bonding part 16 of the inner surface of the can body 2 will become difficult. On the contrary, when it becomes thicker than 45 micrometers, the problem of the handling at the time of conveyance will disappear, but since it becomes difficult to cut | disconnect a film easily and it coats with thickness more than necessary, it is not economical.

As the raw material of the can body 2 of this embodiment, the can body material for three-piece cans generally used is used. For example, tin-free steel having a two-layer coating of metal Cr and hydrated oxide Cr, a tin-based steel plate subjected to Sn plating and a clomate treatment, Ni plating, and then a thin Sn And metal plates such as ultra-thin Sn-plated steel sheets subjected to plating and clomate treatment, and Ni-plated steel sheets subjected to Ni plating and clomate treatment. On one surface (surface constituting the inner surface of the can body) of this metal plate, a coating layer (which becomes the inner surface coating layer 19 described later) is formed, and a steel sheet having a sheet thickness of 0.10 to 0.25 mm is usually used.

Specifically, after Sn plating with an adhesion amount of 0.5 to 3.0 g / m 2, a Sn-plated steel sheet subjected to chemical conversion treatment, and a Ni plated steel sheet subjected to chemical conversion treatment after Ni plating with an Ni adhesion amount of 0.3 to 2.0 g / m 2, Sn and As Ni adhesion amount, 0.5-2.0 g / m <2> and 0.1-0.5 g / m <2> were plated in order of Ni and Sn, respectively, and the Sn / Ni-plated steel plate which performed the chemical conversion treatment, 50-120 mg / m <2> of metal Cr adhesion amounts, and Cr oxide adhesion amount 5-20 mg / m <2> is chromium chromate-treated steel plate normally called tin free steel.

The outer surface of the can body 2 of the present embodiment is decorated with letters, patterns, or the like. As a method for that purpose, after printing the lubricating film and a pattern to the synthetic resin film, such as a polyethylene film and the dry lamination method which laminated | stacked the film in which the lubricating film was previously apply | coated and printed on the metal plate which apply | coated the adhesive agent, There is a method of laminating a dried film by applying a thermosetting or thermoplastic adhesive on the ink layer to a heated metal plate, and directly bonding the other side of the film on which the surface is printed and lubricated to the metal plate directly. In this way, the resin-coated metal sheet obtained is piped by a braking means of three-piece cans such as ordinary welding cans and adhesive cans.

Next, the inner and outer surface coated films applied to this embodiment are polyester resin films. This type of resin film has a high melting point of about 260 ° C. by selecting an alcohol component and an acid component, and also by providing stretching orientation, heat resistance in the tube making step and the filling step can be ensured. Applicability is wide and preferable.

Although the inner surface coating film 19 is a thermoplastic resin film having a thickness of 20 μm or less, a thickness of less than 5 μm is not preferable because the film is scratched in the tube making process, which causes the rusting. . In addition, in order to ensure rust resistance, the thicker the film, the better, but if it is too thick, the economy becomes worse. Therefore, the thickness of the inner surface coating film 19 to be laminated is preferably in the range of 5 to 20 µm.

On the other hand, the outer coated film 21 is often printed with a display of canned contents, a trademark, or the like, and a thermoplastic resin film having a thickness of 20 μm or less is used. If the film thickness is less than 8 µm, the conveyability in the printing step becomes difficult and not preferable. If the film thickness is larger than 20 µm, there is a risk of causing a decrease in appearance and is not economical. Therefore, the thickness of the outer coated film 21 to be laminated is preferably in the range of 8 to 20 µm. In addition, as printing ink, an ink having excellent heat resistance and retort resistance using a urethane resin as a main binder is used, and the thickness of the printing ink layer is varied depending on the printing drawing.

As a printing method, the conventionally known various printing method is used suitably, and gravure printing is preferable in order to improve a printing appearance.

Moreover, you may use an adhesive agent for the coating film laminated | stacked, and in that case, the thickness of an adhesive agent is set in the range of 1 micrometer-10 micrometers. In particular, in order to improve the design on the appearance of the can in the product state, it is preferable to set the thickness of the adhesive within a range of 5 µm to 7 µm. Moreover, in order to conceal the metal color of a metal plate, a white pigment, such as titanium oxide, may be added to an adhesive agent.

In addition, the thermosetting organic coating layer (basecoat layer) which may be used as a base of a coating resin film is laminated | stacked with the sufficient adhesive force on the whole surface of a can size, and the film | membrane which pre-printed is laminated | stacked at the time of steel-making process or after filling the contents. It is to ensure sufficient adhesive strength that does not peel off during heat sterilization. In this thermosetting organic coating layer, a white pigment, such as titanium oxide, may be added in order to further secure the vividness and outstandingness of printing. The pigment added in the thermosetting organic coating layer is selected in the range of 1 to 30% by weight. In the case of adding a white pigment, the effect of whitening is less at less than 1%, and if it is more than 30%, the effect of whitening is almost saturated and the performance of the coating film tends to be deteriorated. A more preferable range is 10 to 25% of range. The thickness of the coating layer which does not contain white pigment may be 1 to 3 µm, and the thickness of the coating layer containing white pigment may be 5 to 15 µm.

The threaded part 10 is formed in the neck part of the junction can body 2 in the direction from which the cap 7 is opened toward the lower side from the upper side of the junction part 16 (overlapping part). Therefore, when opening the cap 7, the inner surface of the screw groove (female thread) 9 of the cap 7 can be turned without being caught by the stepped portion of the joint 16. On the other hand, the stepped portion of the surface of the curl portion 18 formed at the end of the joining can body 2 has a smaller stepped amount than the stepped portion formed on the screw thread 10. This can be achieved by reducing the end of the bonding can body 2 and covering the joint 16 on the inner surface side with a tape-shaped resin film, so that the resistance to the liner when the cap starts to turn when opened. The effect of reducing the opening torque is reduced by making it smaller.

The case of the can which affixed the film is further demonstrated. A joining can body 2 is formed by forming a cylindrical or metal plate coated with a transparent or plain thermoplastic resin film or a white thermoplastic resin film (sometimes titanium white is added to the adhesive layer) or a plain metal plate. Further, the printed thermoplastic resin film is cut to a length not less than the entire circumferential length of the bonded can body 2 to prepare a film for one can, and the outer coated film is formed on the outer circumferential surface of the bonded can body 2. Attach as. By doing in this way, a printing pattern can also be given to the outer surface of the bonding can body 2, also serving as the repair | cover coating of the junction part 16 of the outer surface or the outer surface side.

As said thermoplastic resin film for affixing, for example, homopolyester type resins, such as a polyethylene terephthalate resin and a polybutylene terephthalate resin, copolymerized polyester-type resin which consists of copolymerization of a polyethylene terephthalate and an isophthalate acid, etc., polypropylene A thermoplastic polymer film composed of a single transparent polymer resin selected from a resin, a polycarbonate resin, a polystyrene resin, a polyolefin resin, a vinyl chloride resin, or the like, or a mixture or composite of the above resin is used. And a clear coat layer formed on one surface of the thermoplastic resin film, printing is performed on the surface on the opposite side to the clear coat layer, and as this printing, the gravure printing method, flexographic printing method, inkjet printing method, Screen printing, electrophotographic printing, and the like can be used. Here, from a design point of view, it is preferable to use gravure printing with a clear image quality and high quality.

The adhesive used for the above-mentioned thermoplastic resin film for gluing does not cause film peeling by scissor (smelting), screw cutting, curling, or the like of the water-retaining coating layer described below, and wrinkles and film peeling are caused by retort treatment. It is necessary to select a thing which does not produce | generate, and thermosetting adhesives, such as polyester type, a polyurethane type, an epoxy type, and a polyethylene type, are used.

The polyurethane adhesive is a mixture of polyisocyanate alone or with a compound such as polyor containing active hydrogen, which is easily reacted with an isocyanate group. Specific examples of the polyisocyanate compound include ethylene isocyanate, 1, 6 Aliphatic diisocyanates such as -hexamethylene isocyanate, alicyclic diisocyanates such as isophorone diisocyanate, aromatic diisocyanates such as naphthalene diisocyanate, and the like; As a polyester polyol, a polycarbonate polyor etc. are mentioned.

Moreover, as an epoxy adhesive, bisphenol A or the diglycidyl ether of phenol resin, its oligomer, orthophthalic acid diglycidyl ether, isophthalic acid diglycidyl ether, telephthalic acid diglycidyl ether, etc. are mentioned. In addition, the adhesive used in this embodiment includes, for example, white pigments such as titanium dioxide and zinc oxide, sulfur pigments such as zinc sulfur, red pigments such as scarlet and bengalla, blue pigments such as cinnabar blue and cobalt blue, Green pigments, such as chromium green and green soil, can be mix | blended.

The outermost clear coat layer is provided to improve the slipperiness on the outer surface side of the thermoplastic resin film, to prevent scratches of the film in the high-speed steel making process, and to improve the sheet flow. It is a film with a coefficient of 0.2 or less, and what added Si type microparticles | fine-particles and an organic type lubricant to paints, such as an acryl type and polyester type, is used, for example. Thickness is 0.5-4 micrometers. If it is less than 0.5 micrometer, a friction coefficient does not become small and an effect is not seen. When it exceeds 4 micrometers, there is no further fall of a friction coefficient, and an effect becomes saturated. The clear coat layer is for improving the slipperiness on the outer surface side of the thermoplastic resin film or for preventing scratches. As a clear coat layer, what added hardening | curing agents, such as an amino resin, to polyester resin, an epoxy resin, an epoxy modified polyester resin, and an acrylic resin is used, for example. Here, you may make a hardening | curing agent contain a well-known lubricant.

In addition, in the outer side printing film pasted as a can with a film, the length in the circumferential direction is set to be about 0.5 mm to 5 mm longer than the entire circumferential length of the can body 2, and the length of the outer side printing film is the can body 0.3 mm-1 mm is set so that it may not protrude more than the height of (2). In addition, for the metal exposed portion not covered with the film, it is preferable to repair the coating in view of preventing rust. For example, by pressing the felt material including the paint near the both ends of the cylindrical container body to which the outer printing film is attached, It is desirable to put it.

Here, the printing method of the decoration performed on the outer surface of the can body is not limited to the method of the present embodiment described above, and the can inner surface of the metal plate which is a conventionally used decorative method, that is, a large plate of a material for can body. The coating is applied in terms of the contents retention (corrosion resistance) on the surface corresponding to the surface of the can, and the printing coating method for directly printing the trademark design for the contents display on the surface corresponding to the outer surface of the can can be adopted. As a lot correspondence, a method of printing by applying a printing drawing and forming a cylindrical heat-shrinkable thermoplastic resin film on a plain can to heat-shrink it to decorate it can also be adopted.

[Example]

The outer coated film was coated with 2 µm of a thermosetting polyester paint added with a silicone lubricant to a 12 µm biaxially stretched polyester film and dried, followed by gravure printing of four color trademark designs on the opposite side (2 µm), The thing which added titanium oxide to the urethane type adhesive of 5 micrometers was apply | coated and dried on this printing ink layer. The total thickness of the prepared printed film was 21 μm.

As for the inner surface coating film, the total thickness of the film of 1 micrometer of urethane adhesives was 12 micrometers to the 11 micrometer biaxially stretched polyester film.

On the other hand, the above-mentioned printed film and the inner surface coating film were thermocompression-bonded to the steel plate which performed the normal chromium chromate treatment of plate | board thickness 0.19mm and hardness T2.5, respectively.

From the laminated metal sheet thus obtained, the laminated metal sheet is cut into the size of one can so that the surface of the printed film becomes the can outer surface, and formed into a cylindrical shape, and the joining cans welded by overlapping and welding the ends of the metal plates. The body is manufactured (step difference 0.06 mm of the junction of the can body), and the junction 16 is repaired and coated by an epoxy resin-based thermosetting paint 22 (see FIG. 7) on the outer surface side of the junction can body, and the junction 16 ), The inner surface side was repair-coated with the tape-shaped polyester resin film 20.

Therefore, the 1st layer of the inner surface film of the joining can body is comprised by the thermoplastic resin of melting | fusing point 205 degreeC, and the 2nd layer is comprised by the thermoplastic resin of melting | fusing point of 235 degreeC and biaxially oriented, Moreover, melting | fusing point of the thermoplastic resin which comprises a 2nd layer is 30 degreeC higher than melting | fusing point of the thermoplastic resin which comprises a 1st layer. The thickness of the first layer is 82% of the total thickness of the tape-shaped resin film.

A 200-diameter bonded can body (can barrel inner diameter φ 50) manufactured in this manner was expanded to a diameter of 202, and a neck-inward process was performed a plurality of times at one opening end of the expanded unprocessed to obtain a neck having a shaft diameter of 20%. After forming the inner diameter φ40, folding the open end to overlap, performing pre-culling and screw-cutting to form the thread 10, and then forming a seam curl (pressing the pre-curl) to form a step on the surface of the curl portion. Should be 0.04 mm or less. And bead molding was performed. Subsequently, an aluminum cap (epoxy-phenol resin in which an olefinic resin powder is dispersed on the inner surface side of the cap is applied to the container portion in which the thread is formed, and a liner of a low density polyethylene and an ethylene-propylene rubber copolymer is applied to the liner. By pressing the respective forming rolls (not shown) of the screw cutting roll and the fixed fastening roll against the circumference of the cap while applying a pressing force to the cap top plate using a known capping device. The cylindrical portion of the cap of the cap is deformed to form a screw groove (female thread) so as to follow the screw thread (male screw) of the container, and the lower end of the peeler proof band formed at the edge of the skirt is formed. The cap is attached to the container bent portion by winding it so as to be engaged with the upper end of the bead portion. Prepared can container.

After a proper amount of hot water at 80 ° C. was filled in the can container with screws, the bottom lid was wound around the other opening of the can body and sealed, and pressure sterilization was performed at 125 ° C. for 30 minutes in a retort pot. After that, when the opening torque was measured, a can container with a screw in which the stepped portion of the joint was directed in the opposite direction to the opening direction (the stepped portion in the screw groove and the trace of the step transferred to the cap turned the cap in the opening direction). As a result, the opening torque can be reduced by about 10% in comparison with the can container in which the screws are formed to engage each other.

After opening, the presence or absence of foreign matter adhered to the outer surface of the can body and the inner surface of the cap, in particular, the junction portion or the vicinity of the can body was confirmed, but there was no adhesion problem of the coating film and there was no quality problem. However, although the opening direction of the present embodiment is a right screw, the stepped portion of the joint may be directed in the same direction as the opening direction, and can be applied to the left screw.

Claims (4)

Cylindrical container body portion having an overlapping junction with a stepped portion formed on a side surface, and a container bend formed with a thread and a curl portion at an open end of the container body portion. And a cap having a bottom lid wound around the lower end of the trunk portion, and having a cap formed with a resin sealing liner on the inner surface side of the top plate, In a can container with a screw in which a screw groove is formed in the skirt portion of the cap in accordance with an acid, and the cap is sealed around the container portion. The screw thread is formed in a direction in which a cap is opened from the upper side to the lower side of the stepped portion superimposed with respect to the joint portion, The junction part of which the step of the said junction part is set to 0.07 mm or less, and the said container sphere is reduced by 15% or more with respect to a can body diameter, and is located in the top surface part of the said container sphere part. The can container with a screw characterized by the step of which is set to 0.05 mm or less. The method according to claim 1, The at least inner surface side junction part of the said container trunk part is coat | covered with the repair layer which stuck the thermoplastic resin film, The can container with a screw characterized by the above-mentioned. The method according to claim 2, The part which coat | covers the said junction part among the said thermoplastic resin films is comprised by the tape-shaped resin film, The width | variety of the said tape-shaped resin film in the circumferential direction of the said trunk | drum is set to 7-15 mm, While the thickness of the tape-shaped resin film is set to 15㎛ to 45㎛, The said tape-shaped resin film has a 1st layer which opposes the said junction part, and has a 2nd layer which overlaps with this 1st layer, and touches the content in the inner surface side of the said trunk | drum, The said 1st layer has a melting point Melting | fusing point of this 175 degreeC-230 degreeC, said 2nd layer is 200 degreeC-255 degreeC, and is comprised by resin of biaxially-oriented, and melting | fusing point of resin which comprises the said 2nd layer, 15 degreeC-80 degreeC higher than melting | fusing point of resin which comprises the said 1st layer, and the thickness of the said 1st layer is set to the thickness exceeding 70% of the total thickness of the said tape-shaped resin film, Cans containers. delete

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