JPH0586337A - Production of self-adhesive sheet - Google Patents

Abstract

PURPOSE:To eliminate a defect in quality, a bumpy surface, of a self-adhesive sheet in its production process. CONSTITUTION:A self-adhesive sheet is produced by passing a laminated sheet consisting of a release substrate, a release agent, a self-adhesive, and a surface substrate through a surface leveler 9 having two rolls between which the gap is controllable. Thus, the bumpiness on the surface of the laminated sheet is smoothed out and the printability is remarkably improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for improving the quality of a pressure-sensitive adhesive sheet, and more particularly to a manufacturing method for improving a quality abnormality which occurs in a pressure-sensitive adhesive sheet after lamination in a pressure-sensitive adhesive processing step into a stable non-defective product.

[0002]

2. Description of the Related Art In a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive is processed on the back surface of a front surface base material, and a release base material processed with a release agent is attached before use. When the pressure-sensitive adhesive sheet is used, the release layer can be peeled off and the pressure-sensitive adhesive layer can be directly attached to an adherend without requiring any special adhesion means.

Such an adhesive sheet is often used as a label or the like by printing on a surface base material. There are various types of laminating base materials and laminating agents, and by combining them, a pressure-sensitive adhesive sheet suitable for an application is manufactured.

Various kinds of paper are used as the surface base material and the release base material in quantity, and various kinds of films and composite base materials are used. As the release agent for adhesion, silicone having various properties is often used, and many kinds of adhesive are also used according to the purpose of use and the processing step.

The method for producing a pressure-sensitive adhesive sheet includes a method of directly applying the pressure-sensitive adhesive to the surface base material and then bonding the release layer, or applying the pressure-sensitive adhesive to the release base material and then applying the pressure-sensitive adhesive to the surface substrate. There is a method of bonding materials to each other and transferring the adhesive to the surface base material.

FIG. 1 shows a schematic side view of a conventional adhesive sheet manufacturing machine, which is a method for transferring an adhesive to a surface substrate. The release substrate is fed from (1), the release agent is applied and dried in (2) and (3), and then the adhesive is applied and dried in (4) and (5). On the other hand, the surface substrate is fed from (6),
Laminating with (7) laminating nip roll, (8)
It is rolled up to form an adhesive sheet.

FIG. 4 is a conceptual diagram showing a cross section of a surface base material, a release base material, and a pressure-sensitive adhesive sheet bonded by a conventional manufacturing method. This surface substrate is the most commonly used cast coated paper for adhesive paper, and the surface is mirror-finished and extremely smooth, while the back surface has a relatively uneven paper thickness. The release substrate is glassine paper with a high density and a relatively uniform paper thickness. Moreover, the release agent and the adhesive have a uniform thickness. Then, the surface smoothness of the pressure-sensitive adhesive paper after the surface substrate and the pressure-sensitive adhesive / release agent / release substrate are bonded together is impaired to such an extent that the quality becomes abnormal.

Since a composite base material laminated with a film used as a surface base material or a release base material is also produced by applying the film surface to a mirror surface, the surface of the pressure-sensitive adhesive sheet can be adhered by laminating like the cast coated paper. There is a problem that the smoothness deteriorates.

Since many types of base materials are used for the adhesive sheet and the coating and drying process is complicated, it is often the case that the layers are attached to a single sheet with a built-in strain. There is no problem as long as the thickness, tightness, strength and elasticity of each layer are uniform, but in practice, various characteristics are not basically uniform, and inevitably different and non-uniform ones will be combined. ..

The unevenness generated on the surface of the pressure-sensitive adhesive sheet by the bonding as described above is generally referred to as bobbing. The largest cause of this is thought to be the variation in thickness with built-in strain as described above, but this portion is emphasized when the concave portions and the concave portions or the convex portions and the convex portions overlap. This part is irregularly distributed in the sheet flow direction and the sheet width direction. In addition, expansion and contraction and expansion and contraction occur due to the temperature and tension in the process, which further enhances the lumpiness.

When the lumpiness is severe, not only the appearance of the pressure-sensitive adhesive sheet is deteriorated, but also in printing, the ink transfer and the ink absorption are nonuniform, and a good printing effect cannot be obtained.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a manufacturing method for improving a stable non-defective product, which is caused by the abnormal quality of the adhesive sheet after being laminated in the adhesive processing step.

[0013]

The present invention relates to a method for producing a pressure-sensitive adhesive sheet comprising a release base material, a release agent, a pressure sensitive adhesive and a surface base material laminated, and a paper surface having at least two gap adjusting rolls after the lamination. A method for producing a pressure-sensitive adhesive sheet, which comprises smoothing the surface through a straightening device.

[0014]

According to a preferred embodiment of the present invention, after the laminating step of the pressure sensitive adhesive sheet manufacturing machine, a paper surface straightening device having at least two gap adjusting rolls is installed, and after pasting, the paper surface straightening device is continuously passed through this device, Is a method for improving the pressure-sensitive adhesive sheet by smoothing. In addition, a method of smoothing the surface of a pressure-sensitive adhesive sheet that has been laminated and wound by a pressure-sensitive adhesive sheet manufacturing machine through a separately installed sheet straightening device may be used.

A detailed description will be given below with reference to the drawings. Figure 1
Is a conventional pressure-sensitive adhesive sheet manufacturing machine, as described in detail above, after applying the release agent to the release base material, the adhesive agent is applied, and then the surface base material is bonded to the surface base material. Transfer to material. FIG. 2 is a schematic view of a pressure-sensitive adhesive sheet manufacturing machine of the manufacturing method of the present invention, and shows an example in which a paper surface straightening device having at least two gap adjusting rolls is installed between a bonding nip roll and a pressure-sensitive adhesive sheet winding unit.

When laminating the adhesive sheet manufacturing machine, the elasticity of the soft rubber roll is used as a cushion so that the thickness of the laminating laminate hardly changes. Since each layer of the pressure-sensitive adhesive sheet often has a built-in strain, wrinkles or wrinkles occur when the bonding is performed with a hard roll from the beginning.
It is difficult for the adhesive layer to stick out.

Therefore, in the manufacturing method of the present invention, the sheets are pasted by the conventional pressure-sensitive adhesive sheet manufacturing machine and then passed through the paper surface straightening device. Further, the roll of this apparatus may be a two roll nip through which a rigid roll is inserted in the center and the upper and lower sides are elastic rolls.
The horizontal type or diagonal type can also be used by making the most of its characteristics. Then, two paper surface straightening devices may be installed in succession, and two nips may be passed through, or they may be switched and used during roll maintenance or roll replacement.

FIG. 3 shows an example of a paper surface straightening device of the present invention comprising (10) rigid rolls and (11) elastic rolls. It is preferable that each of these rolls be driven so that the speed can be adjusted.

The rigid roll is placed at a position in contact with the surface base material of the adhesive sheet. The surface property of this rigid roll directly affects the quality of the surface base material of the pressure-sensitive adhesive sheet, so that a special surface treatment is preferred. When the surface substrate is characterized by high smoothness and gloss, for example, chrome-plated mirror rolls are the best for quality improvement purposes.

Even if the elastic roll is a rigid roll, good results can be obtained for smoothing the surface of the pressure-sensitive adhesive sheet.
When various coating widths and base material widths are used, roll scratches are likely to occur at the edge portions, and when scratching the rigid roll, maintenance is very difficult. In that respect, the elastic roll is preferable because it is relatively easy to repair such as polishing. In particular, one roll is preferably an elastic roll in order to protect the rigid roll in contact with the surface base material.

The material of the elastic roll is not particularly limited, and a material that meets each condition is selected from commonly used materials. Various fibers and resins are preferably used as the material of the elastic roll, and more excellent effects can be obtained by using a roll having a high hardness. This is also because the effect of smoothing the surface of the front surface substrate and the back surface of the release substrate is important. This is because if the back surface of the adhesive sheet is uneven, no matter how smooth the surface is, the unevenness of the back surface will be transferred to the front surface during winding. The hardness of the elastic roll is 80 ° in Shore D hardness.
The above is effective and preferable.

The method for adjusting the gap of the paper surface straightening device of the present invention is carried out by using a stopper for finely adjusting the roll surface interval within the range of 10 to 500 μm. The position of the elastic roll is fixed, and the rigid roll is pushed up by the cylinder to the stubber, and the adhesive sheet laminated and laminated is inserted into the gap formed between the elastic roll and the paper to pass through. Alternatively, the rigid roll may be fixed. The adhesive sheet is set to have a narrower gap than the paper thickness after being pasted, and the adhesive sheet is restored to some thickness after passing through the gap. Since the pressure-sensitive adhesive sheets are laminated in various combinations, and the sheet passing speed and the material of the elastic roll are also related, the optimum conditions are empirically determined to set the gap.

FIG. 4 is a conceptual view of a cross section of a conventional pressure-sensitive adhesive sheet, and as described specifically above, the surface smoothness is impaired to the extent that the quality becomes abnormal. FIG. 5 is a conceptual diagram of a cross section of a pressure-sensitive adhesive sheet that has been subjected to paper passing through an apparatus according to the manufacturing method of the present invention to smooth the surface. The smoothness of the front surface and the back surface has been improved and vowels have been eliminated.

[0024]

EXAMPLES Examples will be shown below.

Example 1, Comparative Example 1 Glassine paper 85 g / m² As a release substrate
Release agent 1g / m ², Acrylic emulsion adhesive
20 g / m²Cast coated paper on coated and dried
85 g / m²Were stuck together to produce an adhesive sheet. ratio
Comparative example is a conventional product that is pasted with nip rolls.
An example is a viscous paper smoothed by passing the paper straightening device of the present invention.
It is a wearing sheet. The paper surface straightening device is a mirror surface in contact with the surface base material.
2 of rigid roll and elastic roll with Shore D hardness of 82 °
Use this roll and set the gap with the fine movement adjustment stopper.
Two roll devices, speed 150m / min, gap 18
0 μm, 1 nip paper was used.

The surface of the pressure-sensitive adhesive sheet of the example was greatly improved in the appearance of fluttering and the printing effect as compared with the conventional product of the comparative example. In addition, the value of 70 ° standard gloss is also 82 to 84 to 91.
Improved to ~ 93.

Example 2 and Comparative Example 2 The procedure of Example 1 was repeated except that polyethylene laminated paper was used as the release substrate. Compared with the comparative example, the pressure-sensitive adhesive sheets of the examples were significantly improved in the appearance of surface roughness and the printing effect. The value of 70 ° standard glossiness is 8 from 82 to 84.
It was improved to 5 to 87. Furthermore, the surface of the wound product did not deteriorate even after one month.

Example 3, Comparative Example 3 The procedure of Example 2 was repeated except that a pigment mixed polypropylene laminated paper was used as the surface substrate. The surface of the pressure-sensitive adhesive sheet of the example was significantly improved in the appearance of bumpiness and the printing effect as compared with the comparative example.

Example 4, Comparative Example 4 A double-sided polypropylene laminated paper was used as a release base material, a solvent silicone release agent and an acrylic emulsion pressure-sensitive adhesive were applied and dried, and a vinyl chloride film was bonded to the pressure-sensitive adhesive sheet. The comparative example is a conventional product that is pasted with a nip roll, and the example has a speed of 80 m / min, a roll gap of 200, and one nip sheet. The Shore D hardness of the elastic roll was 85 °. The pressure-sensitive adhesive sheets of the examples had a greatly improved surface bumpy appearance.

[0030]

EFFECTS OF THE INVENTION The pressure-sensitive adhesive sheet obtained by the production method of the present invention is improved in the quality of the uneven flicker that occurs on the surface to a stable quality, and the surface of the pressure-sensitive adhesive sheet has a good appearance with no flicker and a printing effect. Was also greatly improved.

[Brief description of drawings]

FIG. 1 is a schematic side view of a conventional adhesive sheet manufacturing machine.

FIG. 2 is a schematic side view of an example of a pressure-sensitive adhesive sheet manufacturing machine in which the paper surface straightening device of the present invention is installed.

FIG. 3 is a schematic side view of the entire sheet surface straightening device and gap adjustment according to the present invention.

FIG. 4 is a conceptual cross-sectional view of a pressure-sensitive adhesive sheet bonded to a surface base material, a release base material, and a conventional manufacturing method.

FIG. 5 is a conceptual cross-sectional view of a pressure-sensitive adhesive sheet that has been smoothed by passing a sheet straightening device through the production method of the present invention.

[Explanation of symbols]

 1 Release Base Material Unwinding Part 2 Release Agent Coating Part 3 Release Agent Drying Part 4 Adhesive Coating Part 5 Adhesive Drying Part 6 Surface Base Material Unwinding Part 7 Lapping Nip Roll Part 8 Adhesive Sheet Winding Part 9 Paper Correction Device part 10 Rigid roll 11 Elastic roll 12 Cylinder for pressurization 13 Roll gap adjustment 14 Surface base material Cast coated paper 15 Coated layer 16 Base paper layer 17 Lamination paper before release, release material, lamination of adhesive material 18 Glassine paper 19 Release agent Layer 20 Adhesive layer

Claims (3)

[Claims] 1. A method for producing a pressure-sensitive adhesive sheet comprising a release base material, a release agent, a pressure-sensitive adhesive, and a surface base material, which are laminated together, and after the lamination, the surface is smoothed through a paper surface straightening device having at least two gap adjusting rolls. A method of manufacturing a pressure-sensitive adhesive sheet, comprising: 2. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the roll of the paper surface straightening device comprises a mirror-finished rigid roll and an elastic roll having a Shore D hardness of 80 ° or more. 3. The method for producing a pressure-sensitive adhesive sheet according to claim 1, wherein the surface substrate is cast coated paper.