JP7471065B2 - Sleeve printing plate and its manufacturing method - Google Patents

Description

The present invention relates to a sleeve printing plate in which a printing resin layer is provided on the outer peripheral surface of a cylindrical sleeve body, and a method for manufacturing the same.

For example, Patent Document 1 describes such a sleeve printing plate in which at least a sleeve core layer, a cushion layer, a rigid layer, and a seamless printing relief layer are arranged in this order, and the sleeve core layer, cushion layer, and rigid layer all have a uniform surface shape.

Patent Document 2 also describes a seamless sleeve structure for flexographic printing in which at least a core sleeve layer, a cushion layer, a rigid layer, and a seamless printing relief layer are laminated in this order, in which the rigid layer is continuous without interruption and is made of at least one plastic film or sheet, and the films or sheets are laminated in parallel in the width direction of the printing sleeve, forming the entire cushion layer without gaps.

JP 2003-025749 A JP 2006-341468 A

Incidentally, Patent Document 1 describes a method for manufacturing such a sleeve printing plate, in which a cushion layer made of an elastic foam having continuous and/or individual fine bubbles, such as urethane resin, olefin resin, or ethylene-propylene rubber, is attached to the surface of a sleeve core layer made of, for example, a glass fiber reinforced plastic sleeve, with a uniform thickness via an adhesive, and then a sheet-like rigid material (for example, a rectangular biaxially oriented polyester film) having a predetermined width and thickness and thinly coated with an adhesive on one side is spirally wrapped around the surface of the cushion layer to form a rigid layer.

After that, an adhesive is applied to the surface of this rigid layer and dried and cured in a heating oven or the like. After that, as typified by the Seamex process, for example, a sheet-like photosensitive resin plate known as a sheet-like flexographic printing plate made of a photosensitive resin composition that is solid at room temperature is wrapped around the rigid layer, and the ends of the sheet that will become the joints of this sheet-like photosensitive resin plate are fused and bonded by heating them together for several tens of minutes in a heating oven at a temperature above the softening temperature of the photosensitive resin used, for example 120°C.

However, in sleeve printing plates manufactured by this manufacturing method, the sleeve core layer, cushion layer, rigid layer, and printing relief layer are bonded in this order by adhesion with adhesives or pressure sensitive adhesives or by fusion bonding. This makes it difficult to peel the cushion layer, rigid layer, and printing relief layer from the sleeve core layer (sleeve body) made of fiber reinforced resin, and used sleeve printing plates have to be discarded together with the sleeve body.

The present invention was made against this background, and aims to provide a sleeve printing plate that allows the sleeve body formed from fiber-reinforced resin to be easily reused even if the sleeve printing plate has been used, and a method for manufacturing such a sleeve printing plate.

In order to solve the above problems and achieve the above object, the sleeve printing plate of the present invention is characterized in that a resin sheet having a printing resin layer applied to the surface of a supporting resin layer is attached to the outer peripheral surface of a cylindrical sleeve body formed from fiber reinforced resin with double-sided adhesive tape, with the printing resin layer facing the outer peripheral side, the length of the resin sheet and the double-sided adhesive tape in the circumferential direction of the sleeve body is shorter than the circumferential length of the outer peripheral surface of the sleeve body, the resin sheet and the double-sided adhesive tape are spaced circumferentially from each other at the circumferential edges of the sleeve body, and this spaced portion is a joint portion joined together using the same type of resin as the printing resin layer.

In addition, the manufacturing method of the sleeve printing plate of the present invention is configured to form a resin sheet by applying a printing resin layer to the surface of a supporting resin layer, and to attach this resin sheet to the outer peripheral surface of a cylindrical sleeve body formed from fiber reinforced resin with double-sided adhesive tape so that the printing resin layer faces the outer peripheral side, and the length of the resin sheet and the double-sided adhesive tape in the circumferential direction of the sleeve body is shorter than the circumferential length of the outer peripheral surface of the sleeve body, and the resin sheet and the double-sided adhesive tape are attached so that the circumferential edges of the sleeve body are spaced apart in the circumferential direction, and the spaced portions are joined together with the same type of resin as the printing resin layer.

In the sleeve printing plate of the above configuration manufactured by this manufacturing method, the resin sheet formed by applying a printing resin layer to the surface of the support resin layer is attached to the outer peripheral surface of the cylindrical sleeve body formed from fiber-reinforced resin with double-sided adhesive tape, so that the resin sheet can be easily peeled off from the outer peripheral surface of the sleeve body.

Therefore, by peeling off the resin sheet and the double-sided adhesive tape from the sleeve body of a used sleeve printing plate that has been printed with a sleeve printing plate manufactured by the sleeve printing plate manufacturing method described above, and attaching a new resin sheet to the outer peripheral surface of the sleeve body from which the resin sheet and double-sided adhesive tape have been peeled off with the double-sided adhesive tape, it is possible to easily reuse the sleeve body even in the case of a used sleeve printing plate without discarding the entire sleeve body, which is efficient and economical.

Here, in order to facilitate easier peeling from the sleeve body and to reliably support the printed resin layer, it is desirable that the support resin layer of the resin sheet be made of polyethylene terephthalate.

In addition, as in the sleeve printing plate described in Patent Document 1, if a sheet-like rigid material is wound spirally around the surface of a cushion layer to form a rigid layer, or if a sheet-like photosensitive resin plate is wound around this rigid layer and the ends of the sheets that form the seam are heated and fused together, the rigid layer or printing relief layer may become thick in the spirally overlapping parts of the sheet-like rigid material or in the seam parts of the sheet-like photosensitive resin plate.

For this reason, in the sleeve printing plate, the resin sheet and the double-sided adhesive tape are attached so that the circumferential edges of the sleeve body are spaced apart in the circumferential direction, and this spaced apart portion is joined together with the same type of resin as the printed resin layer; and in the manufacturing method for the sleeve printing plate, the resin sheet and the double-sided adhesive tape are attached so that the circumferential edges of the sleeve body are spaced apart in the circumferential direction, and this spaced apart portion is joined together with the same type of resin as the printed resin layer, thereby making the thickness of the printed resin layer uniform .

As described above, according to the present invention, the resin sheet can be easily peeled off from the outer peripheral surface of the sleeve body, and it is no longer necessary to discard the entire sleeve body of a used sleeve printing plate, making it easy to reuse the sleeve body, and therefore sleeve printing plates can be manufactured efficiently and economically.

1 is a perspective view showing one embodiment of a sleeve printing plate of the present invention. FIG. 2 is an enlarged cross-sectional view of the periphery of a joint portion of the resin sheets in the embodiment shown in FIG. 1 . FIG. 2 is a flow chart showing a first step in one embodiment of a method for producing a sleeve printing plate of the present invention. FIG. 4 is a flow chart showing a second step in one embodiment of a method for producing a sleeve printing plate of the present invention. FIG. 4 is a flow chart showing a third step in one embodiment of the method for producing a sleeve printing plate of the present invention.

Figures 1 and 2 show one embodiment of the sleeve printing plate of the present invention, and Figures 3 to 5 explain one embodiment of the manufacturing method of the sleeve printing plate of the present invention. The sleeve printing plate of this embodiment is cylindrical with the axis O as its center, and the innermost periphery is a cylindrical sleeve body 1 made of fiber reinforced resin. A resin sheet 4 having a printing resin layer 3 applied to the surface of a support resin layer 2 is attached to the outer periphery of this sleeve body 1 with a double-sided adhesive tape 5, with the printing resin layer 3 facing the outer periphery.

In this embodiment, the support resin layer 2 of the resin sheet 4 is formed from polyethylene terephthalate. The printed resin layer 3 applied to the surface of the support resin layer 2 is made of a composition consisting of, for example, a binder polymer, a plasticizer, at least one type of ethylenically unsaturated monomer, a photoinitiator, and a thermal polymerization stabilizer. Furthermore, it may contain additives such as a sensitizer and a colorant as necessary.

Of these, the binder polymer may be, for example, a thermoplastic elastomer obtained by polymerizing a monovinyl-substituted aromatic hydrocarbon monomer and a conjugated diene monomer. As the monovinyl-substituted aromatic hydrocarbon monomer, styrene, α-methylstyrene, p-methoxystyrene, etc. may be used, and as the conjugated diene monomer, butadiene-styrene block copolymer, styrene-isoprene-styrene block copolymer, etc. may be used.

Plasticizers are used to impart plasticity, i.e. soft viscosity, to the binder polymer to improve the dispersibility of other compounding agents, and to adjust the flowability and film-forming properties during molding. Suitable plasticizers include aliphatic hydrocarbon oils (e.g. naphthenic acid and paraffin oil), liquid polybutadiene, polyisoprene, polyterpene resins, etc.

The at least one ethylenically unsaturated monomer is compatible with the binder polymer, and examples of such monomers include esters of t-butyl alcohol or lauryl alcohol with acrylic acid or methacrylic acid, or maleimide derivatives such as laurylmaleimide, cyclohexylmaleimide, and benzylmaleimide, esters of alcohols such as dioctyl fumarate with fumaric acid, and esters of polyhydric alcohols such as hexanediol di(meth)acrylate with acrylic acid or methacrylic acid.

The photoinitiator may be selected from or combined with known photoinitiators such as aromatic ketones such as benzophenone, or benzoin ethers such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, α-methylol benzoin methyl ether, α-methoxybenzoin methyl ether, and 2,2-diethoxyphenylacetophenone.

To manufacture such a sleeve printing plate of one embodiment, in the first step, as shown in FIG. 3(a), a cylindrical sleeve body material 11 longer in the axial line O direction than the sleeve body 1 is manufactured from fiber-reinforced resin. Next, as shown in FIG. 3(b), the sleeve body material 11 is rotated around the axial line O, and a cylindrical or cylindrical grinding wheel 12 with an abrasive layer formed on its outer circumferential surface is rotated around a rotation axis parallel to the axial line O. While the abrasive layer of the grinding wheel 12 is brought into contact with the outer circumferential surface of the sleeve body material 11, the grinding wheel 12 is sent out in the axial line O direction relative to the sleeve body material 11, and the outer circumferential surface of the sleeve body material 11 is ground to a predetermined outer diameter. Furthermore, the sleeve body material 11 whose outer circumferential surface has been ground in this way is cut in the axial line O direction as shown in FIG. 3(c), and a sleeve body 1 of a predetermined length is manufactured.

Meanwhile, in the second step, as shown in FIG. 4(a), a sheet-like support resin layer 2 of a certain thickness made of polyethylene terephthalate is supported horizontally, and a printed resin layer 3 is applied to the surface (upper surface) of this support resin layer 2. In applying the printed resin layer 3, as shown in FIG. 4(a), a dripping device 13 is moved in a moving direction F relative to the support resin layer 2 from one end to the other end in the longitudinal direction of the sheet-like support resin layer 2, while the above composition forming the printed resin layer 3 is dripped from this dripping device 13 and poured onto the surface of the support resin layer 2.

The dripping device 13 is also provided with a thickness adjustment blade 13a, the lower edge of which is perpendicular to the support resin layer 2 and spaced a predetermined distance from the surface of the support resin layer 2, on the side opposite the relative movement direction F toward the support resin layer 2. The thickness adjustment blade 13a moves relative to the dripping device 13 in the movement direction F together with the dripping device 13 and is smoothed by the lower edge, so that the printed resin layer 3 is applied to the surface of the support resin layer 2 at a predetermined constant thickness.

The support resin layer 2 with the printed resin layer 3 applied to its surface is then placed below the exposure device 14 with the printed resin layer 3 facing upward as shown in FIG. 4(b), and the printed resin layer 3 is cured by exposure to light from the exposure device 14, thereby producing the resin sheet 4 in this embodiment.

In the third step, the resin sheet 4 thus manufactured is attached to the outer circumferential surface of the sleeve body 1 with the double-sided adhesive tape 5. In this third step, first, as shown in FIG. 5(a), the sleeve body 1 is slowly rotated around the axis O while the double-sided adhesive tape 5, which has adhesive applied to both sides, is lowered in the tangential direction of the outer circumferential surface of the sleeve body 1, and one side of the double-sided adhesive tape 5 facing the outer circumferential surface of the sleeve body 1 is adhered to the outer circumferential surface of the sleeve body 1, and the double-sided adhesive tape 5 is attached so as to be wrapped around the outer circumferential surface of the sleeve body 1.

Next, as shown in FIG. 5(b), the resin sheet 4 is also lowered in the tangential direction of the outer peripheral surface of the sleeve body 1, with the supporting resin layer 2 being attached to the other side of the double-sided adhesive tape 5 facing the outer peripheral side of the sleeve body 1, so that it is wrapped around the outer peripheral surface of the sleeve body 1.

In this embodiment, the length of the resin sheet 4 and the double-sided adhesive tape 5 in the circumferential direction of the sleeve body 1 is slightly shorter than the circumferential length (perimeter) of the outer peripheral surface of the sleeve body 1. As a result, the resin sheet 4 and the double-sided adhesive tape 5 are attached to the outer peripheral surface of the sleeve body 1 with the circumferential edges of the sleeve body 1 spaced apart in the circumferential direction, as shown in FIG. 5(c).

After the resin sheet 4 and double-sided adhesive tape 5 are attached, the spaced apart portion is filled with the same type of resin as the printed resin layer 3 of the resin sheet 4, which is dripped from a dripping device 15 as shown in FIG. 5(c), and then exposed to light in the same manner as the exposure device 14 shown in FIG. 2(b), thereby hardening the resin and forming the joint portion 6. Furthermore, the outer peripheral surface of the joint portion 6 thus formed is polished to be flush with the outer peripheral surface of the printed resin layer 3 of the resin sheet 4.

The sleeve printing plate manufactured in this manner has a printed image formed on the outer peripheral surface of the printing resin layer 3 by laser engraving, and the inner peripheral portion of the sleeve body 1 is fitted into the cylinder of a printing device and used, for example, for printing on the outer peripheral surface of the body of a beverage can. Note that, for alignment with this cylinder, the end of the sleeve printing plate in the direction of the axis O may be formed with a notch (cutout) that is U-shaped or the like when viewed from the outer peripheral side.

In the sleeve printing plate of the above configuration, the resin sheet 4 formed by applying the printing resin layer 3 to the surface of the support resin layer 2 is attached to the outer peripheral surface of the cylindrical sleeve body 1 formed from fiber-reinforced resin with double-sided adhesive tape 5, so that the resin sheet 4 can be easily peeled off from the outer peripheral surface of the sleeve body 1 by peeling off the double-sided adhesive tape 5.

Therefore, by peeling off the resin sheet 4 and double-sided adhesive tape 5 from the sleeve body 1 of a used sleeve printing plate after printing with a sleeve printing plate manufactured by the manufacturing method described above, and attaching a new resin sheet 4 to the outer peripheral surface of the sleeve body 1 from which the resin sheet 4 and double-sided adhesive tape 5 have been peeled off with the double-sided adhesive tape 5, it becomes possible to easily reuse the sleeve body 1 even in the case of a used sleeve printing plate, without having to discard the entire sleeve body 1. This makes it possible to manufacture new sleeve printing plates efficiently and economically.

In addition, in this embodiment, the support resin layer 2 of the resin sheet 4 is formed from polyethylene terephthalate, and although the polyethylene terephthalate that forms this support resin layer 2 has a lower rigidity than the fiber-reinforced resin that forms the sleeve body 1, it can have a higher rigidity than the printed resin layer 3 and the double-sided adhesive tape 5. Therefore, the printed resin layer 3 can be reliably supported for printing, and by peeling the support resin layer 2 from the double-sided adhesive tape 5, the resin sheet 4 can be more easily peeled off from the outer peripheral surface of the sleeve body 1.

Furthermore, in this embodiment, the length of the resin sheet 4 and the double-sided adhesive tape 5 in the circumferential direction of the sleeve body 1 is slightly shorter than the circumferential length (perimeter) of the outer peripheral surface of the sleeve body 1, so that the resin sheet 4 and the double-sided adhesive tape 5 are attached to the outer peripheral surface of the sleeve body 1 with the circumferential edges of the sleeve body 1 spaced apart in the circumferential direction.

These spaced apart portions are joined and hardened with the same type of resin as the printed resin layer 3 of the resin sheet 4 to form a joint 6, and this prevents the printed resin layer 3 from becoming thicker at the spirally overlapping portions of the sheet-shaped rigid material or at the joints of the sheet-shaped photosensitive resin plate, as occurs, for example, in the sleeve printing plate described in Patent Document 1, where a sheet-shaped rigid material is wound spirally around the surface of the cushion layer to form a rigid layer, or where a sheet-shaped photosensitive resin plate is wound around this rigid layer and the ends of the sheets that form the joints are heated and fused together.

In particular, in this embodiment, the outer peripheral surface of the joint 6 is polished after curing so that it is flush with the outer peripheral surface of the printed resin layer 3 of the resin sheet 4. This allows the outer peripheral surface of the printed resin layer 3 to the outer peripheral surface of the joint 6 to be a cylindrical surface centered on the axis O, which prevents ink from accumulating between the printed resin layer 3 and the joint 6 during printing.

REFERENCE SIGNS LIST 1 Sleeve body 2 Support resin layer 3 Printed resin layer 4 Resin sheet 5 Double-sided adhesive tape 6 Joint portion 11 Sleeve body material 12 Grinding stone 13, 15 Dropping device 13a Thickness adjustment blade 14 Exposure device O Axis of sleeve body 1 F Relative movement direction of dropping device 13

Claims (7)

a resin sheet having a support resin layer and a printed resin layer applied to the surface of the support resin layer is attached to an outer peripheral surface of a cylindrical sleeve body formed of a fiber-reinforced resin by a double-sided adhesive tape with the printed resin layer facing the outer peripheral side;
A sleeve printing plate characterized in that the length of the resin sheet and the double-sided adhesive tape in the circumferential direction of the sleeve body is shorter than the circumferential length of the outer peripheral surface of the sleeve body, the resin sheet and the double-sided adhesive tape have circumferentially spaced edges of the sleeve body, and this spaced portion is a joint portion joined together using the same type of resin as the printing resin layer. The sleeve printing plate according to claim 1, characterized in that the supporting resin layer is formed from polyethylene terephthalate. The sleeve printing plate according to claim 1 or 2, characterized in that the printing resin layer contains a plasticizer selected from aliphatic hydrocarbon oil, liquid polybutadiene, liquid polyisoprene, and polyterpene resin. A printing resin layer is applied to the surface of the supporting resin layer to form a resin sheet;
The resin sheet is attached to the outer peripheral surface of a cylindrical sleeve body formed of fiber reinforced resin with a double-sided adhesive tape so that the printed resin layer faces the outer peripheral side, and the length of the resin sheet and the double-sided adhesive tape in the circumferential direction of the sleeve body is shorter than the circumferential length of the outer peripheral surface of the sleeve body,
The resin sheet and the double-sided adhesive tape are attached to the sleeve body such that the circumferential edges of the sleeve body are spaced apart in the circumferential direction,
The method for producing a sleeve printing plate is characterized in that the spaced apart portions are joined together using the same type of resin as the printing resin layer. The method for manufacturing a sleeve printing plate according to claim 4, characterized in that the supporting resin layer is formed from polyethylene terephthalate. The method for producing a sleeve printing plate according to claim 4 or 5, characterized in that the printing resin layer contains a plasticizer selected from aliphatic hydrocarbon oil, liquid polybutadiene, liquid polyisoprene, and polyterpene resin. A method for manufacturing a sleeve printing plate according to any one of claims 4 to 6, comprising the steps of: peeling off the resin sheet and the double-sided adhesive tape from the sleeve body of a used sleeve printing plate that has been printed using the sleeve printing plate manufactured by the method for manufacturing a sleeve printing plate according to any one of claims 4 to 6;
a second resin sheet being attached to the outer peripheral surface of the sleeve body from which the second resin sheet and the second double-sided adhesive tape have been peeled off, using the second double-sided adhesive tape;

Images