JP2005182934A - Label for optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive label for an optical disk which does not deform a disk even when being stuck to the disk and has no risk that dust or the like is stuck to the label after the label is stuck to the disk. <P>SOLUTION: In the label for the optical disk which is to be stuck to a surface opposite to an light incident surface of the optical disk and has a thermosensitive adhesive 3 provided on the rear surface of a label base material 2, the label base material 2 is constituted of a film having ≤250 (N/mm) product of the tensile elastic modulus measured according to JIS K 7127 and the thickness. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical disc label that is attached to an optical disc.

  Conventionally, an optical disk has been widely used as a medium in which electronic information can be stored by a laser. Optical discs are roughly classified into read-only types such as CD-ROM and DVD-ROM, once-write types such as CD-R, and rewritable types such as CD-RW and DVD-RW, and have been mass-produced in recent years. . As a means for decorating such an optical disc, a desired display is directly printed on the surface opposite to the light incident surface (hereinafter sometimes referred to as “label surface”) by silk screen printing. It is difficult to represent delicate depictions in printing. In this regard, if a label is used, an optical disk excellent in decorating properties can be easily obtained. When a label is used to decorate an optical disk, it is applied to an optical disk in the form of an adhesive label coated with an adhesive. It is possible to wear it.

  However, when an adhesive label is affixed to the optical disc, the adhesive is slightly ejected from the peripheral edge of the label, so that there is a problem that dust or the like adheres to the peripheral edge of the label. If an optical disk to which dust is attached is used in this way, it may cause a failure of a disk reader (drive) that is a precision machine. Furthermore, the pressure-sensitive adhesive label requires a release paper, which increases the cost. On the other hand, since there is a possibility of causing a reading error if the optical disk is largely deformed by attaching a label, it is necessary to pay attention to this point.

  SUMMARY OF THE INVENTION Accordingly, it is a first object of the present invention to provide an inexpensive optical disc label that is free of dust and the like, and further provides an optical disc label that is difficult to deform even if it is attached. Is a second problem.

The present invention provides an optical disk label that is attached to the opposite surface of the light incident surface of the optical disk and has a heat-sensitive adhesive provided on the back surface of the label substrate.
Since such a label has a heat-sensitive adhesive on the back surface, it can be attached to an optical disk by heating. On the other hand, since the heat-sensitive adhesive is not sticky in the cold state, there is no possibility that dust or the like adheres to the peripheral portion of the label. Moreover, since the label provided with such a heat-sensitive adhesive does not require a release paper, the cost can be reduced as compared with the pressure-sensitive adhesive label.

  Furthermore, the label substrate is made of a film whose product of tensile elastic modulus and thickness measured in accordance with JIS K 7127 is 250 (N / mm) or less, and this is placed on the label surface of the optical disc. Even if the label is attached while heating the disk, it is difficult to deform the optical disk, which is preferable. Here, the tensile modulus measured in accordance with JIS K 7127 is the tensile strength of the film measured in accordance with JIS K 7127 (1999) under test piece type 2 (width 15 mm), test speed 50 mm / min, room temperature 20 ° C. It refers to the elastic modulus.

  The optical disk label of the present invention can be provided at a lower cost than an adhesive label, and since there is no possibility of dust adhering to the optical disk label after it is affixed to the optical disk, it is loaded into a disk reader that dislikes dust. It is suitable as a label for optical disks. In addition, the optical disk label according to claim 2 is particularly suitable because it is difficult to deform the optical disk even if the label is heated and pasted. Therefore, even if such an optical disk is loaded into a disk reader, no reading error occurs.

Hereinafter, the present invention will be specifically described with reference to the drawings.
In FIG. 1A, a label 1 is provided with an adhesive layer 3 made of a heat-sensitive adhesive on the back surface of a label substrate 2. Specifically, the label 1 has a structure in which an adhesive layer 3 made of a heat-sensitive adhesive, a design printing layer 5, a label base material 2, and a surface protective layer 6 are laminated in this order from the lower layer.
Examples of the label base 2 include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene and polypropylene, synthetic resin films such as polycarbonate, polystyrene, and polyvinyl chloride, polyester-based synthetic paper (for example, Crisper (trade name), etc.), polyolefins Various films such as synthetic paper such as synthetic paper (such as YUPO (trade name)) can be used. Moreover, you may use the laminated | multilayer film which consists of a 2 or more types of laminated body. Such a label base material 2 has a heat shrinkage rate (immersion in hot water at 80 ° C. for 10 seconds) in the MD direction and the TD direction of 1% or less, preferably 0.5% or less, and does not substantially heat shrink. A film is used. The label substrate 2 has a thickness of about 5 to 100 μm.
Specifically, for example, when the substrate is attached to an optical disk made of polycarbonate, the label base 2 is a film having a product of a tensile elastic modulus and a thickness measured in accordance with JIS K 7127 of 250 (N / mm) or less. It is preferable to use a film of 200 (N / mm) or less, more preferably 190 (N / mm) or less. This is because if a film larger than such a numerical value is used, the optical disk may be deformed when attached to an optical disk made of a polycarbonate substrate. On the other hand, if the label substrate 2 is not too thin, the handleability is poor, and there is a risk of wrinkling when affixed to an optical disc. Therefore, a film having a product of a tensile elastic modulus and a thickness of 30 (N / mm) or more. Is preferably used, and more preferably 50 (N / mm) or more. Specific examples of a preferable film used as the label substrate 2 include a polyethylene terephthalate film having a thickness of about 5 to 50 μm, a polypropylene film having a thickness of 20 to 70 μm, and a polyester synthetic paper having a thickness of 20 to 50 μm.
In addition, the label base material 2 of this embodiment in which the design printing layer 5 is provided in the lower layer of the label base material 2 uses a colorless and transparent or colored transparent label base material 2 so that the design printing layer 5 can be seen through.

The design print layer 5 is printed with a desired display such as a product name, a company name, a product description, various advertisements, and a pattern in a single color or a multi-color print. A known printing method may be used as the printing method, but it is preferable to form the design printing layer 5 using an offset printing method because the image reproducibility is good and the image can be printed relatively beautifully. Although it does not specifically limit as a printing ink, A well-known ink can be used, but since it is comparatively excellent in heat resistance, it is preferable to use an ultraviolet curable ink.
The surface protective layer 6 is not particularly limited as long as it can enhance the surface protection and gloss of the label. For example, the surface protective layer 6 can be formed by applying an ultraviolet curable varnish or the like.
Examples of the heat-sensitive adhesive constituting the adhesive layer 3 include an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-methyl methacrylate copolymer. 1 type (s) or 2 or more types can be used and various additives, such as a tackifier and a wax, may be mix | blended. The heat-sensitive adhesive is preferably melted at about 60 to 140 ° C. to produce adhesiveness and 40 ° C. or less (preferably 50 ° C. or less) and not sticky. If the adhesion temperature is too low, blocking may occur when the label is wound into a roll, and if it is too high, the label may shrink or the optical disk may be deformed when the label is applied. Such a heat-sensitive adhesive can be heated and melted and applied to the label substrate 2 by extrusion coating or the like. The solvent type or aqueous emulsion type can also be applied by gravure coating or the like. The thickness of the adhesive layer 3 is formed to be about 5 to 30 μm.

  The optical disk label 1 can be produced by cutting out a label original sheet in which each layer is provided on a long film according to the label surface shape of the optical disk. For example, in an industrial manufacturing process, a roll body in which a label original sheet is wound in a roll shape is mounted on a labeling device, and is drawn out into a label surface shape while being pulled out, and the obtained label is placed on the label surface of an optical disk. Then, this is passed between heating rollers of the laminating apparatus (for example, a heating temperature of 100 to 130 ° C., a speed of 0.25 to 0.8 m / min), and from above and below the optical disk (the light incident surface of the optical disk and the surface of the label 1). By applying heat, a label is attached by a heat-sensitive adhesive, and by repeating this, an optical disc with a label is continuously produced.

  The optical disk to which the label 1 of the present invention can be attached is not particularly limited. For example, CD-ROM (Compact Disk Read Only Memory), CD-R (Compact Disk Recordable), CD-RW (Compact Disk ReWritable), CD such as CD (Compact Disc Disital Audio) for music, DVD-ROM (Digital Versatile Disk Read Only Memory), DVD-R, DVD + R (Digital Versatile Disk Recordable), DVD-RW, DVD + RW (Digital Versatile Disk ReWritable), DVD -It can be attached to DVD such as RAM (Digital Versatile Disk Random Access Memory). Usually, these optical discs are generally used in a disk shape having a diameter of 12 cm and a thickness of about 1.2 to 1.4 mm. However, a disk shape having a diameter of 8 cm or a card shape such as a planar rectangular shape is used. It is also possible to stick it to things. Here, the general-purpose CD structure is a disk-shaped one having a diameter of 12 cm in which a recording layer, a vapor deposition layer, and a protective layer are laminated on a polycarbonate substrate having a thickness of about 1.2 to 1.4 mm. A disk-shaped substrate having a diameter of 12 cm in which two polycarbonate substrates having a thickness of about 0.6 mm are bonded, and a recording layer, a vapor deposition layer and the like are laminated between the two substrates.

Since the label 1 of the present invention is attached to an optical disk via a heat-sensitive adhesive, it does not have adhesiveness after attachment, and therefore there is no possibility that dust or the like adheres to the peripheral portion of the label 1. In addition, since the heat-sensitive adhesive does not exhibit tackiness at room temperature, it is not necessary to supply the label 1 by sticking it to a release paper, and it is not bulky when rolled up into a roll at the time of manufacture. The roll body can be wound up for a relatively long time. In addition, since the design printing layer 5 is provided in the back surface of the transparent label base material 2, the label 1 is excellent in the decoration property because the printed display appears in the glitter due to the light reflection of the vapor deposition layer surface of the optical disk. Yes.
Furthermore, since the label base material 2 is made of a film having a product of a tensile elastic modulus and a thickness measured in accordance with JIS K 7127 of 250 (N / mm) or less, the optical disk is deformed after the label 1 is attached. Can be prevented. The reason for this is not clear, but the optical disk substrate becomes soft enough to be deformed when a load is applied due to the heating at the time of application, and at the same time, the heated thermosensitive adhesive pulls the label when adhering to the optical disk. As a result, the label bends inwardly, and as a result, the optical disk substrate in the above state is curved so as to follow the deformation of the label, and after cooling, it tries to be restored to its original shape by the shape retention of the optical disk substrate. However, it is presumed that the deformed label cannot be pushed back if the label is strong.

The present invention is not limited to the above-described embodiment, and can be appropriately changed in design within the scope intended by the present invention.
For example, in the above embodiment, the design print layer 5 is provided on the back surface of the label base material 2, but the design print layer 5 may be provided on the surface of the label base material 2. Also in such a case, it is preferable to use a transparent film for the label base 2 so that the light reflection on the vapor deposition layer surface of the optical disc can be visually recognized through the label 1.
Further, as shown in FIG. 1B, an adhesive layer 3 (no printing layer is provided) is provided on the back surface of the label base material 2, and an ink receiving layer 7 is provided on the surface of the label base material 2. It may be done. Similarly, the label 1 according to this modification can be attached to the optical disc by heating. Since the ink receiving layer 7 is provided on the surface of the label 1, the user can perform desired printing using a commercially available ink jet printer or the like, for example, CD-R, DVD It is suitable as a once-write type optical disc label such as -R or a rewritable type optical disc such as CD-RW or DVD-RW.

EXAMPLES Hereinafter, an Example is shown and this invention is explained in full detail. However, the present invention is not limited to the following examples.
Examples 1-10
The film (label base material) shown in Table 1 was coated with a heat-sensitive adhesive mainly composed of ethylene-vinyl acetate at 240 ° C. so as to have a dry thickness of 25 μm. This was punched out according to the shape of the optical disc, and labels according to Examples 1 to 10 were produced. This was placed on the label surfaces of the two types of optical disks shown in Table 1, respectively, passed through a laminating apparatus (130 ° C., speed 0.5 mm / min), and heated from the top and bottom of the optical disk to attach a label. After leaving it in the room for about 1 minute to cool down, the label peripheral part of the obtained optical disc with label was carefully touched, and none of them was found to be sticky.
Next, as shown in FIG. 2, when the presence / absence of deformation was confirmed by placing the light incident surface of this labeled optical disk on a flat surface, as shown in Table 1, for some examples, the light incident surface Was slightly curved with the inside. In Table 1, “slightly curved” indicates that the maximum bending height H (see FIG. 2) is less than 0.5 mm, and “curved” indicates that the height is 0.5 mm or more. . Next, when the label attached to the curved optical disk was forcibly peeled off, all the optical disks were restored to a flat shape, and the peeled label was curled inside (with the adhesive layer inside). Further, when the optical disk which was not curved was forcibly peeled in the same manner, the peeled label was similarly rounded inward.

引張弾性率は、ＪＩＳ Ｋ ７１２７（１９９９年）に従い、試験片タイプ２（幅１５ｍｍ）、試験速度５０ｍｍ／分、室温２０℃下で測定。

The tensile modulus was measured in accordance with JIS K 7127 (1999) under test piece type 2 (width 15 mm), test speed 50 mm / min, and room temperature at 20 ° C.

  From the above results, the label having a product of the tensile modulus of elasticity and the thickness of the film used is approximately 250 N / mm or less can prevent the deformation of the optical disc, and particularly for CD, the product is approximately 180 to 200 N / mm or less. It turns out that the thing of this is preferable.

(A) is a partially omitted sectional view showing an optical disk label of the present invention, and (b) is a partially omitted sectional view showing an optical disk label according to a modification of the present invention. The reference side view which shows the curved state of the optical disk at the time of sticking a label.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disc label, 2 ... Label base material, 3 ... Adhesive layer, 5 ... Design printing layer, 6 ... Surface protective layer, 7 ... Ink receiving layer

Claims (2)

An optical disc label that is affixed to the opposite surface of the light incident surface of the optical disc
A label for an optical disc, wherein a heat-sensitive adhesive is provided on the back surface of the label substrate. The optical disk label according to claim 1, wherein the label substrate is made of a film having a product of a tensile elastic modulus and a thickness measured in accordance with JIS K 7127 of 250 (N / mm) or less.

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