JPH0124430B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for manufacturing a multilayer adhesive sheet, and provides a method for manufacturing a flat multilayer adhesive sheet using a large-diameter drum winding method. Conventional applications for multilayer adhesive sheets include, for example, at the entrances of hospital operating rooms and examination rooms where dust should not be allowed to enter, to remove dust and bacteria that have adhered to the soles of people's shoes, the tires of trolleys, etc. There is a dustproof sheet. This is made up of multiple adhesive sheets that are laminated together so that they can be peeled off one after another when the surface becomes dirty.Since productivity is usually good, adhesive is applied to a synthetic resin base film. It is manufactured by winding it around a diameter drum to a desired thickness, cutting the laminate on the drum in its axial direction, and developing it into a plate shape. However, although this method has good productivity, it has the following drawbacks because it is made into a plate by opening up the wound material in multiple layers. In other words, as shown in Figures 1 and 2, there is actually an inner side (the side closer to the drum surface) and an outer side (the opposite side).
b means that the length of the circumference is π(R+
2d) Since the difference is −πR=2πd (see FIG. 3), the sheet located on the outside b swells as shown in FIG. 1, a so-called gearing phenomenon occurs, and a cavity c′ is generated inside. Furthermore, as shown in FIG. 2, due to the curl, the plate is bent inward a and curled, making it impossible to obtain a plate with a correct plane. In order to correct the problem, it is not only necessary to perform aging by applying heat and pressure treatment for a long time, but also there is a risk that the problem will occur again during use. The present invention improves these conventional drawbacks and makes it possible to efficiently obtain a flat multilayer pressure-sensitive adhesive sheet. That is, as a result of various studies, the present inventors have found that before winding a synthetic resin base film coated with an adhesive onto a large-diameter drum, the film is heated to 40 to 60°C before the winding drum. By taking it out, when it is cut into a flat plate after being rolled up,
The present invention was achieved by recognizing that the above-mentioned gearing phenomenon does not occur. The reason for this is not clear, but as the winding diameter increases, the tension increases, and this tension and temperature stretch the film.Therefore, as the number of layers increases (toward the outside), the shrinkage stress increases, and this causes stress during cutting. It is presumed that this causes contraction, and the lengths of the inner and outer sides become equal, and gearing does not occur. Furthermore, the flat multilayer adhesive sheet obtained in this manner is passed through a multi-stage roll whose surface temperature is 60 to 90°C, and is subjected to a treatment that gives it a undulating meandering motion at this temperature, thereby eliminating curls. It was confirmed that the problem was resolved and the occurrence of curls could be further prevented. It is presumed that this treatment alleviates tension unevenness (distortion) during winding and, together with the preceding heat treatment immediately before winding, promotes the curl prevention effect. In the present invention, gearing occurs when the temperature during winding is 40°C or lower, and the temperature of the multi-stage roll is 60°C or lower.
If the temperature is below ℃, the curl prevention effect will not be sufficiently demonstrated, and the winding temperature will exceed 60℃, and the multi-stage roll temperature will increase.
If the temperature exceeds 90℃, the sheet may stretch during winding.
Wrinkles may occur, and the multilayer adhesive sheet may be misaligned.
Inconveniences such as warping and other deformation occur, making it difficult to fully achieve the object of the present invention. Examples will be specifically illustrated below to further clarify the embodiments and effects of the present invention. Example 1 A multilayer adhesive sheet was manufactured under the following conditions using an apparatus equipped with an unwinder 1, a nip roll 2, a tatsuchi roll 3, a large-diameter drum 4, and a heater 5 as shown in FIG. 6 is an adhesive film, and 7 is a wound multilayer adhesive sheet. Thirty layers of an adhesive film having a 55μ polyethylene sheet and a 5μ thick acrylic adhesive layer were wound around a large diameter drum of R=320mm rotating at 5 rpm. This was cut and developed to obtain a multilayer adhesive sheet, and the results after being left for 2 days were as shown in Table 1.

[Table] Example 2 The same procedure as in Example 1 was carried out except that the large-diameter drum 4 had an R of 500 mm, the Tatsuchiroll 3 had an R of 100 mm, and the apparatus shown in Fig. 5 was used, and the same results as in Table 1 were obtained. Ta. Example 3 A 60μ thick polyethylene sheet 6 with a 5μ adhesive coated on the surface was prepared using a device similar to that shown in Figure 5.
(width: 500 mm) was heated to various temperatures by heater 5 and wound onto a large diameter drum of 320 mm at a speed of 5 m/min. Multilayer adhesive sheet 7 obtained by cutting
As shown in Figure 6, rolls 8 of 80mmφ are spaced apart.
Speed of 3m/between multiple rolls arranged at 2.2mm
Processing was performed to allow the train to pass in a meandering manner at min. Table 2 shows the conditions at this time and the amount of curl and appearance before and after this roll treatment. Note that the a value in the table is X ₁ + before multi-roll treatment.
X ₂ /2, and the b value is also X ₁ +X ₂ /2 (see FIG. 2) after processing. From Table 2, it can be seen that Test Nos. 5, 6, 7, 10, 11, 13, 14, and 15, which fall within the range of the conditions of the present invention, had a small curl amount of 10 mm or less and exhibited excellent effects.

【table】 [Brief explanation of drawings]

Figure 1 is an enlarged cross-sectional view of the multilayer adhesive sheet showing the geared state, Figure 2 is an enlarged cross-sectional view also showing the curled state, Figure 3 is a side view of the large diameter drum on which the film is wound, and Figure 4. FIG. 5 is a side view illustrating the manner in which the film is wound up, and FIG. 6 is a side view illustrating the manner in which the multilayer adhesive sheet is processed with multistage rolls. 1...Adhesive film unwinding machine, 2...Nipprol, 3...Tatsuchiroll, 4...Large diameter drum,
5...Heater, 6...Adhesive film, 7...Multilayer adhesive sheet, 8...Multi-stage roll.

Claims (1)

[Claims] 1. In manufacturing a flat multilayer adhesive sheet by applying an adhesive to a synthetic resin base film and winding it onto a large-diameter drum, and cutting the film on the drum in its axial direction, A method for producing a multilayer adhesive sheet, which comprises heating the film to 40 to 60°C before winding it onto a large-diameter drum. 2 Coating adhesive onto a synthetic resin base film and winding it onto a large diameter drum, cutting the film on the drum in the axial direction to produce a flat multilayer adhesive sheet, and winding it onto a large diameter drum. The film was heated to 40 to 60°C in front, and the flat multilayer adhesive sheet, which was wound and cut to a predetermined thickness, was heated to a temperature of 40 to 60°C.
A method for producing a multilayer adhesive sheet, characterized by passing it in a meandering manner between multistage rolls at a temperature of 60 to 90°C.