JPH0767946B2 - Labeled plastic bottle and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a labeled plastic bottle and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, as a method for attaching a long label to a plastic bottle while cutting it into a predetermined size,
For example, a method is known and widely used in which a glue is applied to the entire back surface of a paper label and then attached to a plastic bottle.

However, the method of applying the glue to the entire back surface is intended only to wind and fix the label on the plastic bottle, and the plastic bottle can be recycled for use, or the label can be a predetermined label. No consideration is given to removing the label from the plastic bottle when it is not stuck in place. Therefore, when the label is peeled off, a part of the glue or the paper label remains on the surface of the plastic bottle together with the glue, and there is a problem that it is expensive to remove the part of the glue or the paper label when the label is reused. Further, in the case of a label made of a plastic film having poor water absorption, it takes a long time for the glue to exhibit adhesiveness, so that there is a problem that the wrapped label is easily separated from the bottle.

On the other hand, Japanese Patent Publication No. 63-17706 discloses a method of attaching a label to a plastic bottle with only a part of the adhesive and easily recycling the plastic bottle. However, this method involves dissolving a part of the label with a solvent and adhering the part of the label that is temporarily bonded to the plastic bottle and the seam of the label. Since it dissolves in the solvent, the solvent exudes to the adhesive part of the label and the adhesive part of the label where the plastic bottle coated with the solvent is overlapped, which not only damages the appearance of the label surface but also causes the strength of the label to decrease. .

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to reliably use a hot-melting agent to attach a plastic film label to a plastic bottle. The label can be temporarily adhered to the label and wrapped around it, and the hot melt agent can be easily removed together with the label when the label is to be removed in a sufficiently cooled room temperature state without impairing the appearance and physical properties of the label. It is an object of the present invention to provide a labeled plastic bottle and a manufacturing method thereof, which can reduce the reuse cost of the plastic bottle.

[0006]

[Means for Solving the Problems] Under the circumstances described above, the present inventors have earnestly studied a method of attaching a plastic film label to a plastic bottle, and as a result, the plastic bottle without impairing the appearance and physical properties of the label. It has been found that it is effective to combine a hot-melting agent in attaching the label to the, and the present invention has been completed.

That is, the above-mentioned object of the present invention includes any one of the adhesive strength of the hot melt agent with the plastic bottle at room temperature, the adhesive strength between the hot melt agent and the label, and the base material strength of the label and the hot melt agent. This is accomplished by applying the label to a plastic bottle using a smaller hot melt agent.

More specifically, the front end of the label is temporarily adhered to the plastic bottle via the hot melt agent, and the rear end of the label wrapped around the plastic bottle is overlapped and adhered to the front end. In this case, it is achieved by using the hot melt agent on the boundary surface.

The label is preferably a non-foaming or effervescent thin flexible thin plastic film, and the surface to be printed is subjected to corona treatment in advance and then the desired printing is usually performed. , The printed pattern is continuously repeated in the direction of wrapping around a plastic bottle and is wound into a roll. This is called a label blank that is cut into a predetermined length according to the thickness of the bottle to be pasted, but printing ink may or may not be present in the hot melt agent application part. It doesn't matter if you don't.

As the material of the film, polypropylene resin, polystyrene resin, polyvinyl chloride resin, P
ET resin or a laminated type composite film or the like whose contact surface with a bottle is made of these materials is preferably used, but a polypropylene resin which is less likely to be deformed such as shrinkage due to heat of the hot melt agent is preferably used. it can. Further, the optimum one is selected according to the material of the plastic bottle to be wrapped. For example, in the case of a PET bottle, the film is preferably a polypropylene-based resin, a polystyrene-based resin, polyvinyl chloride, or a laminated composite sheet whose contact surface with the bottle is made of these materials. In the case of a PP bottle, the film is preferably a polystyrene-based resin, PET resin, polyvinyl chloride, or a laminate type composite sheet whose contact surface with the bottle is made of these materials. Label thickness of 0.01 to 0.10 mm is recommended.

The material of the plastic bottle is not particularly limited, and there are PET, PP, PVC, nitrile resin, etc.,
Mention may be made of single-layer or multi-layer bottles of these resins.
As for the shape, it is preferable that the surface covered with the label is vertical and that the body portion of that portion is cylindrical.

[0012] The hot-melt agent requires an adhesive force capable of firmly fixing the back surface of the leading end portion of the label to the plastic bottle in the step of winding the label, and returns to room temperature after the label is wrapped around the plastic bottle. The adhesive strength gradually weakens with the use of a material that has the ability to easily peel from the surface of a plastic bottle in a sufficiently cooled normal temperature state, and the adhesive strength with the plastic bottle is 0.01 to 5 kg at an ambient temperature of 0 to 40 ° C. /25.4mm
Can be used.

If the adhesive strength exceeds 5 kg / 25.4 mm at room temperature, the label and the hot melt agent may be torn and left on the surface of the bottle when peeling off the label from the plastic bottle, and the residue is removed from the surface of the plastic bottle. However, it takes much time and cohesive failure of the hot melt agent is likely to occur. Further, if the adhesive strength is less than 0.01 kg / 25.4 mm, the bond between the label and the bottle or between the labels is weak, and the label may peel off during use.

The adhesive strength referred to here is that a hot-melting agent melted at 180 ° C. is applied to a film of a material to be used having a thickness of 0.05 mm at a coating amount of 2 g / m in a line shape having a width of 25.4 mm, This is a value obtained by measuring at 20 ° C. at a peeling angle of 180 °, a peeling speed of 200 mm / min, and making a sample by press-bonding this to a PET sheet having a thickness of 0.5 mm or more.

The composition of the hot-melt agent may be one that is generally used and mainly comprises a base polymer, a tackifier, a wax and a plasticizer, and the type and amount are selected depending on the materials of the plastic label and the bottle. Examples of this base polymer include ethylene / vinyl acetate copolymers, ethylene / ethyl acrylate copolymers, polyethylene, polypropylene, ethylene / (meth) acrylic acid copolymers and metal salts thereof, ethylene / methyl methacrylate copolymers. Polymer, styrene / butadiene / styrene block copolymer, styrene / isoprene / styrene block copolymer, styrene / ethylene / butylene / styrene block copolymer,
Examples thereof include ethylene / butene copolymer, ethylene / propylene rubber, ethylene / propylene / butene copolymer, butyl rubber, polyester, polyamide, polyisobutylene, and saponified ethylene / vinyl acetate copolymer. These may be used alone or in two kinds. A combination of the above is usually added in the range of 10 to 100% by weight in all the tissue components.

Examples of the tackifier include aliphatic petroleum resins, aromatic petroleum resins, alicyclic petroleum resins, terpene resins, rosins and rosin derivatives, hydrogenated resins, terpene phenol resins and coumarone. Examples thereof include indene resin and xylene resin, and these are used alone or in combination of two or more kinds, and usually used in the range of 0 to 90% by weight in the entire composition.

Specific examples of the wax include natural wax, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, polyethylene wax, polypropylene wax, and oxides or acid-modified products thereof, which may be used alone or in combination.
0 to 90% by weight in the total composition, usually in combination of more than one kind
It is used by blending within the range.

Examples of the plasticizer include paraffin oil, aroma oil, naphthene oil liquid paraffin, liquid polybutene, dioctyl phthalate, dibutyl phthalate, etc. These are usually used alone or in combination of two or more. It is used in the composition in the range of 0 to 40% by weight.

To produce the plastic bottle with the label according to the present invention, additives other than those mentioned above can be used within the range not impairing the object of the present invention. As such additives, known antioxidants, colorants, fillers,
Examples include UV inhibitors.

To produce the hot melt adhesive used in the present invention, the above raw materials are melted (usually 150 to 200).
It may be mixed by a conventional method at (° C).

To attach a label to a plastic bottle, the hot-melting agent is usually melted at 150 to 200 ° C. and then applied to the tip of the back surface of the label cut into a predetermined size. When the label is pressed against the bottle, the tip portion of the label is bonded to the plastic bottle, so that when the bottle is rotated, the label is wrapped around the body of the bottle without being displaced. On the other hand, by applying the hot-melting agent to the rear end portion of the back surface of the label, when the label is wrapped around the plastic bottle, the rear end portion is overlapped and attached to the front end portion of the label.

The amount of the hot melt agent applied may be such that the label does not deviate from the plastic bottle during the label winding operation at the leading end of the label, in the form of one or several dots, or in the form of a thin strip. But it doesn't matter.
Further, at the rear end portion of the label, a strip shape is preferable, but a portion having no hot melt agent may be patterned in the strip shape. The amount of the hot melt agent applied to the rear end portion of the label is preferably larger than that to the front end portion.

[0023]

With the above construction, the hot-melt agent at the leading end of the label temporarily adheres to the plastic bottle without shifting the label, and the hot-melt agent at the rear end causes the leading end and the rear end of the label to stick together. Since it is firmly bonded and the plastic bottle can be beautifully covered with a label, a product with high commercial value can be obtained in high yield. Also, when removing the label later, the adhesive strength between the label and the bottle is weaker than the adhesive strength between the labels, so the label can be easily peeled off from the bottle, and the hot melt agent or the label on the bottle surface can be easily removed. No fragments remain, and the cost of reusing plastic bottles is greatly reduced.

[0024]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is an explanatory view showing the main parts of a typical apparatus used for manufacturing a plastic bottle with a label according to the present invention.

The printed long label 1 made of plastic is cut into a predetermined width, wound in a roll shape, placed on a stand provided in the apparatus, and successively fed out. The extended long label passes through a detector for cutting and positioning, is nipped by a feed roll, and is sent to the cutter 2.

A mark for deciding the cutting position is printed in advance on the label, and a blank is cut by the cutter 2 with the detector so as to have a predetermined cutting position and a cutting dimension. The blank 3 is sucked by the vacuum drum 6 and is rotated and moved together with the vacuum drum while being attached to the surface of the vacuum drum 6. A projection 4 as shown in FIG. 4 is formed on the vacuum drum 6 at a position where the hot melt agent of the blank 3 is to be applied, and the hot melt is applied by a coating roller 5 at a position corresponding to the projection portion of the blank 3. The agent is applied.

On the other hand, the plastic bottles 7 sent by the conveyor are moved one by one by a star-shaped wheel 8 at a predetermined interval and brought into contact with the blank 3. Almost at the same time as the contact, the blank 3 is adhered to the surface of the plastic bottle 7 by the hot melt agent 9 at the label tip portion in the molten state. The hot melt agent 9 at the label tip portion is sandwiched between the blank 3 on the vacuum drum 6 and the plastic bottle 7 and stretched to accurately fix the blank 3, and when the plastic bottle 7 continues to move while rotating on the conveyor, the blank 3 Is wrapped around the plastic bottle 7.

The hot melt agent 10 is applied to the rear end portion of the blank 3 by the hot melt agent application roller 5, and the blank 3 is wound around the body of the plastic bottle 7 as described above. At this time, the blank 3 is overlapped with the tip portion and pressure-bonded, and the rear end portion is bonded to the tip portion.

FIG. 2 is a view immediately before the blank 3 on the vacuum drum 6 contacts the plastic bottle 7.
After the hot melt agent 9 at the tip of the blank 3 is adhered to the plastic bottle 7, the plastic bottle 7 moves while rotating, so that the blank 3 is wound around the plastic bottle 7. The hot melt agent 10 at the rear end portion of the blank 3 is superposed on the front end portion of the blank 3 wrapped around the plastic bottle 7 by pressure bonding and adhesion. FIG. 3 shows a plastic bottle 7 around which the blank 3 is wrapped.

Next, an example of producing a plastic bottle 7 around which the blank 3 is wound by using the above apparatus will be described. Example A label made of PP film was attached to a PET bottle using a lapping machine as shown in FIG. The label was prepared by printing on the treated surface of a PP film having a thickness of 0.05 mm which was previously corona treated. The PET bottle used had a capacity of 1.5 liters, a round waist, and a vertical portion of 120 mm.

The vacuum drum 6 has a plurality of protrusions 4 so that the hot-melting agent is applied to two positions of the front end and the rear end of one blank. The projections of the portions are strip-shaped so that the hot melt agent can be applied to the rear end portion more widely than the front end portion.

The hot melt agent has a softening point of 130 ° C. and 180
A melt viscosity at 2000C of 2000 cp (MT melt: manufactured by Mitsui Toatsu Chemical) was used. Hot melt agent 1
The label was applied at 90 ° C. and a coating roller at a speed of 150 sheets / min. Immediately after that, the tip of the label is adhered to the PET bottle, the bottle rotates and the rear end of the label is overlaid on the tip and adhered with the hot melt agent. A coated bottle could be molded. Cut off the bonded part of this hot melt agent,
If the label is peeled off in a sufficiently cooled state, the adhesive strength will be
It was 2.2 kg / 25.4 mm and could be peeled off without the hot-melt agent or the label remaining on the surface of the PET bottle.

Comparative Example Molding was carried out in the same manner as in the above example except that the coating area of the hot melt agent at the leading end portion of the label was wider than that at the rear end portion. The label was not displaced and was good, but when the label was peeled off, some of the hot melt agent remained in the PET bottle.

Table 1 shows the test results of attaching labels to the surface of PET bottles using the hot-melt agents having the compositions shown in Examples 1 to 4 together with the test results of Comparative Examples 1 and 2. There is. In any of the examples, no misalignment occurs when the label is wrapped, and when the label is peeled off from the one left to stand in the atmosphere of 20 ° C after the label is attached, the hot melt agent or the label fragments are stuck on the surface of the plastic bottle. Did not remain at all. On the other hand, with the compositions of the hot-melt agents shown in Comparative Examples 1 and 2, as a result of performing the same operation, the hot-melt agent remained on the surfaces of the plastic bottles.

[0035]

[Table 1]

[0036]

According to the present invention, the plastic bottle and the label are temporarily adhered to each other by the hot melt agent at the leading end portion of the label without being displaced, and the leading end portion and the rear end portion of the label are caused by the hot melt agent at the rear end portion. Since it is firmly adhered and the plastic bottle can be beautifully covered with the label, a product with high commercial value can be obtained in high yield. Further, when it becomes necessary to remove the label later, the label can be easily peeled off from the plastic bottle, and the reuse cost of the plastic bottle is greatly reduced.

[Brief description of drawings]

FIG. 1 is an explanatory view showing main parts of a typical apparatus used for producing a labeled plastic bottle according to the present invention.

FIG. 2 is an explanatory diagram showing a state immediately before a label comes into contact with a plastic bottle on a vacuum drum.

FIG. 3 is a plastic bottle having a label according to the present invention attached thereto.

FIG. 4 is a view showing a state in which a leading end portion of a label on a vacuum drum is in contact with a hot melt agent application roller.

[Explanation of symbols] 1 long label 2 cutter 3 label blank 4 protrusion 5 coating roller 6 vacuum drum 7 plastic bottle 8 wheel 9,10 hot melt agent

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Claims (14)

[Claims] 1. A rectangular label made of a printed plastic film is wrapped around the outer circumference of a body of a plastic bottle, the front end of the back surface of the label is the front surface of the bottle, and the rear end of the label is the front surface of the rolled label. A label-attached plastic bottle formed by adhering each with a hot melt agent, wherein the adhesive strength at the interface between the plastic bottle and the hot melt agent is smaller than the adhesive strength at the interface between the hot melt agent and the label. Labeled plastic bottle characterized by being bonded by. 2. The hot melt agent is applied in a larger area on the rear end of the label than on the rear end thereof.
A plastic bottle with the label described in. 3. The label according to claim 1, wherein the adhesive strength of the interface between the hot melt agent and the plastic bottle at room temperature is lower than the label base material strength and the hot melt agent base material strength. Plastic bottle. 4. The adhesive strength at the interface between the hot melt agent and the plastic bottle is 0.01 to 5 kg at an ambient temperature of 0 to 40 ° C.
A plastic bottle with the label according to any one of claims 1 to 3 having a size of /25.4 mm. 5. The plastic bottle provided with the label according to any one of claims 1 to 4, wherein the plastic bottle is a PET bottle. 6. The plastic bottle provided with the label according to any one of claims 1 to 5, wherein the plastic film is a PP film or a multilayer film of PP whose surface in contact with the plastic bottle. 7. A plastic bottle provided with the label according to claim 1, wherein the printed surface of the plastic film is corona-treated. 8. A long label which has been printed is cut into a predetermined size to form a rectangular label, and the label is adhered to a continuously rotating vacuum drum and conveyed during the step of conveying. In the method of applying the hot melt agent to the front and rear ends of the back surface of the label, and wrapping and sticking the above label on the surface of the plastic bottle sent while rotating at a predetermined interval, the front end of the back surface of the label As the hot melt agent applied to the portion and the rear end portion, use a hot melt agent having an adhesive strength at the interface between the plastic bottle and the hot melt agent at room temperature that is smaller than the adhesive strength at the interface between the hot melt agent and the label. How to attach a label to a plastic bottle characterized by. 9. The method of applying a label according to claim 8, wherein the hot melt agent is applied to a rear end portion of the back surface of the label in a larger area than a front end portion thereof. 10. The hot melt agent according to claim 8 or 9, wherein the adhesive strength at the interface between the plastic bottle and the hot melt agent at room temperature is lower than the label base material strength and the hot melt agent base material strength. How to attach labels. 11. The adhesive strength at the interface between the hot melt agent and the plastic bottle is 0.01 to 5 kg at an ambient temperature of 0 to 40 ° C.
A method for applying the label according to any one of claims 8 to 10, wherein a hot melt agent having a size of /25.4 mm is used. 12. The method for applying the label according to claim 8, wherein the plastic bottle is a PET bottle. 13. The plastic bottle provided with the label according to any one of claims 8 to 12, wherein the plastic film is a PP film or a multilayer film of PP whose surface in contact with the plastic bottle. 14. The method for applying the label according to claim 8, wherein the printed surface of the plastic film is subjected to corona treatment.