JPH04325585A - double sided adhesive tape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided adhesive tape having a polyurethane foam as a support.

0002

[Prior Art] Conventionally, double-sided adhesive tapes, which have adhesive layers on both sides of a support made of polyurethane foam with a thickness of about 1 to 5 mm, have excellent cushioning properties and a good balance between strength and hook hangers. Used for fixing mirrors, etc.

0003

[Problems to be Solved by the Invention] However, the polyurethane foam used in conventional products has a low foaming skin with an expansion ratio of 10 times or less that occurs during foam molding, and the entire surface of this skin has small irregularities. formed and the surface smoothness is poor. Therefore, even if a pressure bonding load of 2 kg/cm2 or more is applied, only about 50% of the effective bonding area is obtained, resulting in poor initial adhesion and low reliability of adhesive strength. Therefore, in order to increase the effective bonding area by pressure bonding, the internal foaming ratio is increased and the ratio of the foaming ratio to the center of the surface area is 0.3 to 0.
．． It had to be around 6. By the way, if there is a large difference in the foaming ratio between the skin layer and the center, there is a problem that the compressive hardness decreases and sagging or internal displacement is likely to occur, which may cause fixed objects to fall. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and provide a double-sided adhesive tape that does not sag and can ensure a large effective adhesive area.

[0005]

[Means for Solving the Problems] The present invention provides a double-sided adhesive tape having a polyurethane foam as a support, wherein the polyurethane foam has an expansion ratio of 0.8 or more to the center of the surface area. The gist is that the foaming ratio in the center is 10 to 50 times.

[0006] The adhesive used in the present invention may be either rubber-based or acrylic-based, and the thickness of the adhesive layer is 25 mm.
It is preferable to set it to 100 micrometers. Further, as described above, a polyurethane foam having a relatively small difference in expansion ratio between the surface portion and the center portion can be obtained by extrusion foam molding on a polyethylene terephthalate film, for example.

[0007]

[Function] The double-sided adhesive tape of the present invention has a smooth surface with no irregularities, and the ratio of the foaming ratio of the surface area to the center area is
Since polyurethane foam with a foaming ratio of 0.8 or more and a center expansion ratio of 10 to 50 times is used as the support, the compression hardness of the support is 50 g/cm2 (10% modulus).
Despite the above, an effective adhesive area of 90% or more can be secured with a pressure bonding load of 2 kg/cm2. Therefore, the initial adhesive strength is high and the holding strength is stable over time.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be explained in detail with reference to FIG. Example A polyurethane foam with a foaming ratio of 25.5 times in the surface area, a foaming ratio of 30 times in the center area (a ratio of expansion ratio of the surface area to the center area of 0.85) and a thickness of 5 mm was used as the support 1, and both sides of the foam were , dry weight of acrylic adhesive 50g/m2
Adhesive layers 2 and 2 were formed by coating to obtain a double-sided adhesive tape.

[0009] The expansion ratios of the surface portion and the center portion are measured by dividing the foam into approximately three equal parts in the thickness direction, and measuring both sides as the surface portion and the center portion as the center portion. The obtained adhesive tape,
Effective adhesion was determined by a sensory evaluation method in which a piece of 10 cm x 10 cm was pasted on a polished glass plate, pressed from the top with a pressure of 2 kg/cm2, and the area of the adhesive part was visually observed from the back and calculated by comparing it with a standard. In addition to calculating the area, interlaminar strength and compressive hardness (10%) were measured. In addition, practical tests were conducted regarding wear and drop.

[0010] Effective adhesive area is 90%, interlayer strength is 2.
The weight was 9 kg/cm2, the compression hardness was 65 g/cm2, there was no settling, and the number of pieces falling was 0/20. Comparative Example Same as the example except that a support made of polyurethane foam with a foaming ratio of 9 times in the surface area and 30 times in the center area (ratio of expansion ratio of the surface area to the center area: 0.3) was used. A double-sided adhesive tape was obtained, and physical properties were measured and practical tests were conducted.

[0011] Effective bonding area is 50%, interlayer strength is 2.
The weight was 1 kg/cm2, the compression hardness was 40 g/cm2, the set was large, and the number of pieces falling was 5/20.

0012

[Effects of the Invention] Since the double-sided adhesive tape of the present invention is constructed as described above, it is possible to increase the effective bonding area and improve the initial bonding strength, and also to significantly reduce the sag and reduce the weight. The ability to hold objects can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view showing an example of the double-sided pressure-sensitive adhesive tape of the present invention.

[Explanation of symbols]

1 Support 2 Adhesive layer

Claims (1)

[Claims] 1. In a double-sided pressure-sensitive adhesive tape having a polyurethane foam as a support, the polyurethane foam has an expansion ratio of 0.8 or more in the surface area to the center area, and an expansion ratio in the center area of 10 to 10. A double-sided adhesive tape that is 50 times stronger.