JPH02166179A - Process for joining label - Google Patents

Abstract

PURPOSE:To improve the easiness of the work, the joint strength, etc., without detriment to the appearance of a label by winding a label made of a synthetic resin sheet around the entire periphery of the side of a container and joining the both ends of the label together with a solvent which can dissolve the synthetic resin. CONSTITUTION:Many labels are printed contiguously and repeatedly on a long synthetic resin sheet, rolled up into a ring, and fed to a label applicator to be cut to a predetermined length to separate the sheet into individual labels. This label has a printed part (a) on its surface and a part (b) to which a solvent is applied on the rear end D of the back, and the front end A to be superposed on the part (b) of the rear end of the back is composed of a part B to which an ink is applied and a part C where the synthetic resin film part is substantially exposed. This label is wound around a container (c) made of a material such as paper, a synthetic resin, metal or glass, being in the form of a cup, a bottle, a tray or a can and having a straight part of at least 4mm on the side. A solvent which can dissolve the synthetic resin is applied to the part (a), and this part is superposed on the part A to join the front end of the surface to the rear end of the back.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method of wrapping a synthetic resin sheet label around the entire circumference of the side surface of a container, and joining both ends of the label with a solvent that dissolves the synthetic resin sheet. Regarding.

[Conventional technology Beautiful labels are attached to glass bottles, metal cans, and various containers made of synthetic resin. Machines and methods for applying these labels to containers are described, for example, in U.S. Patent No. 4.567.68.
No. 1, No. 4,574,020, No. 4.749.428
It is disclosed in No. 1, etc. In both of these methods, a synthetic resin sheet label is wrapped around the entire circumference of the container and bonded together, and a solvent that dissolves the synthetic resin sheet is applied to the overlapped portion to bond the overlapped portion.

Labels made of synthetic resin sheets are usually printed on their surfaces, but if these printing inks are present at the overlapping joint, the bonding force will be significantly reduced.

Usually, in order to solve these inconvenient phenomena, printing is not performed on the overlapping joint portion, and the synthetic resin sheet portion is exposed on the surface. However, with conventional technology, it is difficult to completely connect the display or pattern printed on the leading edge of the label with the display or pattern printed on the trailing edge in the overlapping area, which makes it difficult to completely connect the label's main function. Significant limitations are placed on the ability to display characters and patterns, and at the same time, the appearance is also significantly impaired.

In other words, when printing synthetic resin sheet labels in multiple colors, there is usually a misalignment between the prints for each color, so the width of the exposed synthetic resin sheet C in the overlapping area A is set wider than the width of the overlapping area A. Must. Since this difference in width must be minute, printing requires a significantly more difficult process than the normal printing process (11), and the label pattern described above becomes discontinuous. This will significantly impede the uniformity of the label display function, which is a feature of all-around wrapped labels in that they can be viewed from all directions around the entire circumference.

In addition, one continuously printed synthetic resin sheet label,
When cutting a single sheet, it is cut according to the printing position, but misalignment occurs during the cutting process itself, so processing with significantly higher precision than the normal cutting process is required. Therefore, when using a normal cutting device, the synthetic resin exposed portion C of the synthetic resin sheet label must be set wider than the overlapping portion A. The inconvenience that the display function, which is the main function of the label, is obstructed becomes even more noticeable.

In addition to the above-mentioned method, there is a method in the prior art in which printing is also applied to the overlapping part A, and a large amount of solvent is applied to the rear surface of the rear end of the label to join the labels, as shown in FIG. 4(b). In this case, the solvent that dissolves in the synthetic resin sheet may flow outside of the overlapping area and disturb the appearance, or cause wrinkles or holes in the overlapping area, which significantly impairs the appearance, which is an important product performance of the label. It will be done.

In addition, especially when applying heat treatment after bonding to heat-shrink the synthetic resin sheet label and make it adhere tightly to the container, the bonding force of the adhesive part is weak, so as shown in Figure 7, the shrinkage force of the label will cause the label to overlap. The bonded portion is pulled left and right, causing misalignment (so-called beer back phenomenon), and if this phenomenon is significant, the problem arises that the label may be peeled off.

In addition, even in cases where heat shrinkage is not performed, defects such as peeling may occur during the transportation process of the container after the label is attached, and if a large amount of solvent is used, odor problems due to residual solvent may occur. There are inconveniences such as having to thoroughly deaerate the container after attaching a label to the container before packaging.

[Problem that the invention seeks to solve]

In bonding the front end surface and the rear end back surface of the label using a solvent that dissolves synthetic resin sheet labels, the inventor has determined that the front end surface and the rear end surface of the label can be bonded without any restrictive conditions. Continuous display of characters and patterns is guaranteed, does not interfere with the appearance of the label, and can be easily performed with ordinary precision printing and cutting operations, or even with simpler equipment than usual. The present invention provides a label bonding method that allows printing and cutting of labels to be carried out and can maintain sufficiently strong bonding strength after the label is affixed.

[Means for solving the invention]

The above problem is that the front end surface part A, which overlaps with the rear end back part of the label, is the printed part B, and the unprinted synthetic resin sheet part of the label is substantially exposed. The problem is solved by a method of applying a solvent that dissolves the synthetic resin to the back side of the rear end of the label, and then joining the front end surface part and the back side of the label.

In addition, the front end surface portion A of the label has at least 10% or more of the synthetic resin sheet portion that is substantially exposed without ink, and the rear end back surface portion of the label is coated with the synthetic resin. It is desirable to attach a solvent that dissolves the label and then bond it to the front end surface of the label.

The container referred to in the present invention is a container made of various materials such as paper, synthetic resin, metal, glass, etc., and has a shape such as a cup,
Bottles, trays, cans, etc. with a small amount on the side (both 4III
Refers to a container with a straight section of IB or higher.

The synthetic resin sheet referred to in the present invention refers to a film, a foam sheet, or a composite sheet having both a film layer and a foam layer.
．． 0.01 to 1.00 m in thickness. The synthetic resin used for the synthetic resin sheet needs to be dissolved in the solvent used for adhesion. Therefore, the material of the synthetic resin sheet and the solvent are mutually selective. For example, when a polystyrene resin is used as the synthetic resin sheet, various solvents such as methylene chloride, 1-1-1-)lychloroethane, and tetrahydrofuran are employed as the solvent. Furthermore, for polyvinyl chloride and the like which are difficult to dissolve in solvents, tetrahydrofuran is the main solvent. Other synthetic resins include polystyrene, polyvinyl chloride, polyacrylate, polyethylene, vinylidene chloride, EVA, etc. Solvents include methylene chloride, l-1-11-lychloroethane, tetrahydrofuran, toluene, xylene, etc. etc.

As a method for joining the tip of the label to the container, a method of applying an adhesive to the label on a boat or a method of using a solvent that dissolves the label material is adopted.

After the label made of the synthetic resin sheet is attached to the container,
In order to heat-shrink the material in a shrinking furnace, it is common to use a sheet that is endowed with heat-shrinking properties, but it is also possible to use a sheet that does not usually heat-shrink, such as a two-wheel stretched sheet or a balance-stretched sheet. It is possible.

That is, the label used to carry out the present invention may be non-heat-shrinkable or heat-shrinkable, and the shrinkage rate may be appropriately selected depending on the shape of the container and the like.

Generally, a large number of labels are continuously and repeatedly printed on a long film, and the label is fed to a label attaching machine in a ring-shaped state. Labels are continuously fed from this ring, and in the next step each label is cut into a predetermined length. In this cutting process, a symbol set at the cutting position on the label is read by a reader installed in the label attaching machine, and then the label is cut at a mechanically controlled position to avoid any misalignment. - For boat fishing, the cutting accuracy is about ±0.1 to ±2.5 m. If cutting accuracy is to be kept within 0 to ±0.1 m, the machine will become very expensive and complicated, and productivity will drop significantly.

Gravure printing is generally used as the printing method for labels, but the printing accuracy for positioning each color ranges from ±0.3 to 1.
It is about 0 m. In order to improve this printing precision, it is necessary to significantly reduce production efficiency and to employ expensive printing machines, similar to cutting operations.

-C uses a resin, pigment, or dye that has good and strong resistance to solvents, and a method of applying a top coat to the surface layer to increase solvent resistance is used, so the label can be dissolved. The presence of ink can significantly weaken the bonding force of solvents that bind. Therefore, if there is no misalignment of printing or cutting positions, adhesive strength and pattern continuity can be maintained well, but in normal production, these misalignments are expected and ink may be present on the bonding surface. Therefore, there are restrictions on the display of characters and pictures, and furthermore, a blank, unprinted area remains following the overlapping area.

〔Example〕

Embodiments of the present invention will be specifically described below with reference to the drawings.

Fig. 1 is a perspective view showing a state in which a label that has been continuously and repeatedly printed is wound into a ring shape, and Fig. 2 is a label cut into individual sheets, which is used to carry out the present invention. Figures 1 and 2 are diagrams showing the front and back sides of the label, in which (a) is a plan view showing the front side of the label (mark [first side]), (b)
Figure 3 is a rear view showing the back side of the label (the side to which the solvent is applied); Figure 3 is a perspective view showing the label attached to the outer periphery of the container; Figure 4 is a plan view showing the surface of a conventional label; (a) is a comparative example in which the label has an exposed portion of the synthetic resin sheet, and b) is a comparative example in which printing is applied to the entire surface of the label. 5 is a perspective view showing a state in which the conventional label shown in FIG. 4(a) is rolled into a cylindrical shape and its both ends overlapped; FIG. 6(a), (b) and (C) is a plan view showing the state of the surface of the label in other embodiments of the present invention;
FIG. 7 is a perspective view showing peeling (beer back) of the overlapping portion when the conventional label of FIG. 4(b) is attached to a container and then heat-shrinked.

The symbols in the figure are as follows.

A is the overlapping part of the joining surfaces, B is the overlapping part where printing is applied, C is the overlapping part where printing is not applied and the synthetic resin sheet is exposed, A is the printed part , the opening is the part where the solvent is applied, C is the container, L is the line indicating the position where the rear end of the label touches the front end of the label, and L' is the line formed after the label is peeled off from side to side after heat shrinkage. .

As shown in FIGS. 2 and 3, the label used in the present invention has a portion where the leading end of the label overlaps A, a printed portion B, and an unprinted portion B. The synthetic resin sheet portion consists of a substantially exposed portion C. The printed part B can be related to the characters and patterns on the leading edge of the label, while the exposed part C, where the synthetic resin seed is exposed, is the part of the opening at the rear end of the label that has been melted with a solvent. By overlapping and integrating, a predetermined stable bonding strength is maintained.

Although some deviation may occur during printing and cutting operations of the label, no problem will occur if the range of the printed portion B is appropriately set according to the accuracy of the operation. Therefore, unlike the prior art shown in FIGS. 4(a) and 5, the display function, which is the main function of the label, is not performed in the overlapped portion, and the function of the all-around wrap label is fulfilled.

In addition, the label not only simplifies and streamlines these manufacturing processes, but also, as shown in Figure 7, when the label is attached and heat-shrinked to make it adhere tightly to the container, the label The exposed portion C of the synthetic resin sheet reacts directly and instantaneously with the opening of the solvent-coated portion on the rear end of the label, thereby increasing the adhesive strength to a predetermined limit value or higher. The leading and trailing edges of the label will not be torn off. Generally, the method of attaching a label to a container and then heat-shrinking it is carried out continuously on the same line, and the usual method is to heat-shrink it immediately after attaching the label.

In one of the conventional technologies shown in Figure 4, etc., the display function of the leading and trailing ends of the label is planned to be continuous, but because ink is present on the adhesive surface, the synthetic resin at the overlapping part of both ends of the label is Because the sheets are not integrated, the bonding force is weakened, and as shown in Figure 7, the leading and trailing edges of the label are peeled off (beer back phenomenon), and in some cases, the overlapping part opens. Defects occur. In addition, there are cases in which the amount of solvent is increased in order to increase adhesive strength, but as mentioned above, the solvent impairs the appearance of the label and significantly impairs its commercial value.

The present invention was carried out using a heat-shrinkable expanded polystyrene label composed of two layers, a skin layer and a foam layer, as a synthetic resin sheet. The label is 150-180 microns thick and has a heat shrinkage rate of 50-60% at about 120°C. The printing method uses normal gravure roll printing,
Printing was performed with color matching accuracy within ±0°8 mm. or,
For cutting, a ring like the one shown in Figure 1 was attached to a label attaching machine, and continuous cutting was performed using fixed force and rotational force. The cutting accuracy was within ±0.7 ms. Ink containing acrylic resin was used, and tetrahydrofuran was used as the solvent.

When ink was present on the bonded surface as shown in FIG. 4(b), about 30 minutes were required for the bonded portion to completely solidify. In addition, the initial bonding strength of the overlapping part is 0.0
5 kg/cm or less, and the heat shrinkage force of the label is 0.1
kg/cm or less.

On the other hand, when using the method of the present invention, for example, the width of A is 7.5
Assuming that the width of m and B is 1.5 m and the width of 5 C is 6 m, the tensile strength of the overlapping part will be 3.0 to 4.
0 kg/cm, making it possible to bond much stronger than heat shrinkage force.

Further, FIG. 6 is a diagram showing another embodiment of the present invention,
5 This is because the exposed part of the synthetic resin sheet part is made using printed patterns etc. without providing a part that has the function of maintaining the joining force over the entire surface of the label in the overlapping part A for joining the labels. This is an example. Part A consists of a part to which ink has adhered (black part in the figure) and a part to which ink has not adhered (white part to the figure), and is marked fi11.
The area ratio of the portion to which no ink is attached is determined depending on the required bonding strength.

According to the evaluation results of the present inventor, the lower limit of the area ratio of the portion where the synthetic resin is not printed and where the synthetic resin is exposed is about 10%. In general, in order to obtain good results and enable stable production, it is preferable that the exposed area is 30% or more.

(in Fig. 6) is an example in which the ink part is 50% and the exposed synthetic resin sheet part is 50% of the part A, which maintains an initial adhesive strength of 2 to 3 kg/c11 in tensile strength, In the heat shrinking process, no beer back phenomenon occurred at the shrinkage portion, and no problems such as peeling on the transportation line occurred. - [Effects of the Invention] Since label attachment is normally performed at high speed, if the work precision of each process is limited, efficiency will be significantly impaired. If the method of the present invention is carried out, the original function of the labeling machine, that is, the function of labeling stably at high speed, will not be lost, and furthermore, the display function, which is the main function of the label, will not be subject to any restrictions. It is possible to fully demonstrate these functions without adding any additional features.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a state in which a label that has been continuously and repeatedly printed is wound into a ring shape, and Fig. 2 is a label cut into individual sheets, which is used to carry out the present invention. FIG. 3 is a diagram showing the front and back sides of the label, where (a) is a plan view showing the front side of the label (printed side), CO> is a rear view showing the back side of the label (the side coated with solvent), and FIG. FIG. 4 is a perspective view showing a state in which the label is attached to the outer periphery of a container, and shows the overlap of the label ends; FIG. 4 is a plan view showing the surface of a conventional label; (b) shows a comparative example in which the label was provided with an exposed portion of the synthetic resin sheet, and (b) shows a comparative example in which the entire surface of the label was printed. FIG. 5 is a perspective view showing the conventional label of FIG. 4(a) rolled into a cylindrical shape with both ends overlapped; FIGS. 6(a), (b) and (C) are Both are plan views showing the state of the surface of the label in other embodiments of the present invention,
FIG. 7 is a perspective view showing peeling (beer back) of the overlapping portion when the conventional label of FIG. 4(b) is attached to a container and then heat-shrinked. A-・−−−−−・・・・・・・・−・−・・−・−・
・−・Overlapping part B of joint surfaces・−・−・−・−・
・・−・−・−・−・−Printed part C in the overlapping area−・−・−・−・−・・−・−・−・〜・・
- The overlapping part where no printing is applied and the synthetic resin sheet is exposed.・・−・−・−・・−・・・−・
・・・−・・Partial bar for applying solvent・−−−−−−1・−・−・・−・−・−・・−・・Container L−・・−
・−・−・−・・・・−・・−・・・・・−・− Line L'−1 ・・−・・−・−−11 indicating the position where the rear end of the label overlaps the front end of the label 1...---The line formed after the label is peeled off from side to side after heat shrinkage

Claims (1)

[Claims] 1) In a method of wrapping and bonding a synthetic resin sheet label around the entire outer circumference of a container, the front end surface portion (A) that overlaps with the rear end back surface portion of the label is coated with ink. (B) and a part (C) where the synthetic resin sheet portion of the label is substantially exposed, and a solvent that dissolves the synthetic resin is applied to the back end of the label. The method for joining a label as described above, characterized in that the front end surface portion and the rear end back surface portion of the label are then joined. 2) In a label joining method in which a synthetic resin sheet label is wrapped and joined all around the outer circumference of the container, the front end surface portion (A) that overlaps with the back end of the label
However, the synthetic resin sheet contains at least 10% of the exposed area without ink, and after applying a solvent that dissolves the synthetic resin to the rear end of the label, The method for joining a label as described above, characterized by joining the front end surface portion and the rear end back surface portion.