JPH0565550B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a double-sided adhesive tape,
More specifically, in a double-sided adhesive tape made by laminating a tape-like material made of a pressure-sensitive adhesive on the surface of a releasable tape, by forming a cured material layer on both ends of the tape-like material, a roll-shaped double-sided adhesive tape is formed. To provide a double-sided adhesive tape that effectively prevents the tape-like material from being accidentally broken when the adhesive tape is unwound or adhered to the surface of an adherend.

<Prior art and its problems> The most widely used type of double-sided adhesive tape is a removable tape with nonwoven fabric,
A support material such as woven cloth, Japanese paper, foamed film, plastic film, or foil is impregnated with and/or coated with a pressure-sensitive adhesive to make it adhesive on both sides, and the adhesive is applied to the core of a paper tube, etc. It is known that the tape is wound into a roll with the tape inside.

Another type is one in which a tape-like material formed by forming a film of pressure-sensitive adhesive is superimposed on the surface of a removable tape without using a carrier as described above, and the tape is wound into a roll in the same manner as above. There is.

These two types of double-sided adhesive tapes are easy to handle because the carrier gives the tape self-supporting properties, and its cushioning ability can be applied even to relatively large rough surfaces. Although it has many advantages such as being able to adhere properly due to its properties, it has disadvantages such as the thickness of the tape hindering the thinning of the products used and the high cost.The latter allows for a thinner and cheaper tape. On the other hand, since there is no carrier, the tape does not have any stiffness, so it easily deforms when handled alone, and the edges of the tape can be easily scratched when unwinding from the tape roll. This has the disadvantage that the tape-like material tears at the starting point and transfers to the back surface of the removable tape.

<Purpose of the Invention> The double-sided adhesive tape of the present invention relates to the latter, that is, a double-sided adhesive tape formed by overlapping a tape-like product formed by forming a film of pressure-sensitive adhesive on the surface of a releasable tape and winding it into a roll. The object of the present invention is to provide a double-sided adhesive tape that can be smoothly unwound without causing the tape-like material to tear and stick to the back side of the peelable tape when it is unwound from a roll tape. be.

Other objects of the invention will be understood from the detailed description below.

<Structure of the Invention> The object of the present invention is to provide a tape-like material formed by forming a film of a pressure-sensitive adhesive on the surface of a removable tape, and a tape-like material formed by forming a film of a pressure-sensitive adhesive on the surface of the removable tape, and a tape-like material formed by forming a film of a pressure-sensitive adhesive on both ends of the tape-like material. This is achieved by integrally forming a fine cured material layer that has a higher Young's modulus than a tape-like material.

According to the double-sided adhesive tape of the present invention, a narrow cured material layer having a Young's modulus higher than that of the tape-like material is integrally provided at both ends of the tape-like material formed by forming a film of pressure-sensitive adhesive. Not only does this allow for smooth unwinding without tearing from the unwinding end of the tape roll and transferring it to the back of the peelable tape, but the cured material is essentially non-adhesive, so when unwinding There is no stringiness at the edges of the tape, and there is no problem of dust adhering to the sides of the tape roll during storage or use, or problems such as tape rolls adhering to each other over time even if the tape rolls are stacked. It has the characteristics of

The double-sided adhesive tape of the present invention is produced by laminating a thermoplastic film such as polyethylene onto a paper material such as kraft paper, or by laminating a low-adhesion film such as silicone resin or fluorine resin onto a single plastic film such as polyethylene film. releasable tapes whose surface is coated with polyurethane resin, or similar products thereof (hereinafter referred to as releasable tapes)
A rubber-based pressure-sensitive adhesive composition mainly composed of natural rubber or synthetic rubber, or a synthetic resin-based pressure-sensitive adhesive composition mainly composed of a synthetic resin such as acrylic resin or polyvinyl ether, alone or in combination with the composition. A pressure-sensitive adhesive film is formed on the surface of the releasable tape by applying a mixture of short fibers such as rayon and vinylon to a thickness of usually 5 to 200 μm using a conventional method. Overlap the tape-like materials. Then, after winding a predetermined amount of tape-like material inside a core made of paper or synthetic resin to form a tape roll, the side surface of the tape roll is supplied with a polymeric hardening substance by coating or other means. By polymerizing and curing this, a narrow cured material layer having a Young's modulus higher than that of the tape-like material is integrally formed on both ends of the tape-like material.

The polymerizable curable material is formed by integrally forming a cured layer on both ends of a tape-like material formed by forming a film of the pressure-sensitive adhesive, and in which the Young's modulus of the cured material layer is lower than that of the tape-like material. There are no particular restrictions as long as the cured material layer shows a high value, but the cured material layer does not substantially impede the adhesiveness of the tape-like object and the objective of improving the physical strength of the end of the tape-like object is achieved most accurately and simply. A photopolymerizable curable material that is polymerized and cured by light irradiation is preferred because it can achieve the following.

The photopolymerizable curable substance is a solution type that contains a photocrosslinking sensitizer as an essential component, blends a photoactive crosslinking agent and/or a vinyl polymer compound as necessary, and dissolves it in an organic solvent. and a photocrosslinking sensitizer and a wettability imparting substance as essential components,
A water dispersion type is used in which a photoactive crosslinking agent and/or a vinyl polymer compound is blended as necessary and dispersed in water.

However, the use of the water dispersion type is disadvantageous when using the solution type, for example, the width of the cured material layer is increased due to penetration of organic solvent from the end of the tape-like material, reducing the effective bonding area. This is preferable because it does not pose any problems in the working environment, such as the evaporation of organic solvents, which may impair the health of workers or pose a risk of fire.

The photocrosslinking sensitizer used in the practice of the present invention is one that has the effect of drawing out active hydrogen in a polymer upon receiving actinic rays, or one that transfers excitation energy from an excited state to the photoactive crosslinking agent. For example, benzophenone, 4-hydroxybenzophenone, 2-chloroanthraquinone, 2-methylanthraquinone, benzoylacetophenone, anthrone, 1,4-naphthoquinone, 9,10-anthraquinone, 1,2 Examples include aromatic ketones such as -benzoanthraquinone, aromatic aldehydes, aromatic carboxylic acids, and organic compounds containing photosensitizing halogen atoms. The amount used is 0.01 to 10% by weight based on water in water dispersion type or organic solvent in solution type.
Preferably it is 0.1 to 5% by weight. If the amount is less than 0.01% by weight, the crosslinking rate due to light irradiation will be slow and the degree of crosslinking will be insufficient.If the amount exceeds 10% by weight, it will be difficult to stabilize the system in the case of water dispersion type, and This is not preferable because it causes problems such as mutual recombination of the crosslinking sensitizers, inhibition of light transmission, resulting in a decrease in crosslinking rate, and high cost.

The photoactive crosslinking agent is activated by receiving excitation energy from actinic light or the sensitizer,
It leads to crosslinking of the vinyl polymer or copolymer in the tape or water dispersion (or solution) formed by forming a film of pressure sensitive adhesive, and the crosslinking rate increases by adding this crosslinking agent. As a result, the light irradiation time is shortened.

Such photoactive crosslinking agents include N・N'-
Methylene bisacrylamide, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 5-acrylamino-N-
Examples include acrylcaproamide. The amount used is in the range of 0.5 to 20% by weight, preferably 1 to 10% by weight, based on the water content of the aqueous dispersion or the organic solvent of the solution. If the amount used is too high, the crosslinking density will become too high and it will become brittle, and cracks will occur in the cured layer unwound from the tape roll, making it impossible to obtain the function of reinforcing the edges of the tape. It is not effective.

For example, when the vinyl polymer compound is added when the photocrosslinking rate of the tape-like material is slow,
Crosslinking occurs between the tape-like material and the added vinyl polymer, which helps increase the strength of the cured product layer, and examples thereof include polyolefins and ethylene copolymers. The amount used is preferably in the range of 1 to 30% by weight based on the water in the aqueous dispersion or the organic solvent in the solution; if it is less than 1% by weight, no effect will be observed, and if it exceeds 30% by weight, This is undesirable because crosslinking becomes insufficient because light transmittance is inhibited, and a cured material layer having the desired physical strength cannot be obtained.

In addition, the wettability-imparting substance used when making a water dispersion is a tape that is difficult to wet with ordinary water dispersions because the end of the tape is made of pressure-sensitive adhesive and has a low-energy surface. Examples of surfactants that cause wetting at the edges of a shaped article include alkylbenzene sulfonate sodium, dialkyl succinate sodium ester, and polyethylene glycol lauryl ether, which have a wetting action.

This usage amount is 0.05~
The content is preferably 5% by weight; if it is less than 0.05% by weight, the desired moisturizing effect cannot be obtained, and if it exceeds 5% by weight, water resistance may deteriorate, which is not preferable.

A solution type containing each of the above-mentioned ingredients can be prepared by dissolving the above-mentioned photocrosslinking sensitizer, photoactive crosslinking agent, and vinyl polymer compound in an organic solvent such as toluene, tetrahydrofuran, methyl ethyl ketone, or acetone. For the water-dispersed type, the photocrosslinking sensitizer is dissolved in advance in the above-mentioned organic solvent, and this is added and dispersed in water together with a surfactant having an effective milky property, and the wettability imparting substance is dispersed therein. It is obtained by When using a photoactive crosslinking agent, it is dissolved in an organic solvent in the same way as a photocrosslinking sensitizer and then dispersed in water together with a surfactant. They can be used and added to water, respectively.

Actinic light sources that cause the crosslinking reaction include xenon lamps, low pressure, high pressure and ultra-high pressure mercury lamps, sunlight, carbon arc light, etc.
Those having a wavelength of 1500 Å to 6000 Å are preferably used.

Generally, the irradiation time is 400W high pressure mercury lamp.
10 to 60 seconds is sufficient; the longer the irradiation time and the greater the output of the light source, the greater the crosslinking density, the stronger the cured layer at the end of the tape, and the easier it is to peel off the tape. It can be reliably peeled off from the surface of the adhesive tape.

In this way, a method such as applying an aqueous dispersion or solution containing at least a photocrosslinking sensitizer to both ends of a tape-like product formed by forming a film of a pressure-sensitive adhesive overlaid on the surface of a releasable tape. The cured layer formed by crosslinking the pressure-sensitive adhesive (tape-like material) itself or the adhesive and the added polymer has a thickness of at least 0.5 μm, preferably 1 to 500 μm, and preferably 30 μm. It has a fine width of ~200 μm, and has a Young's modulus that is at least 1.5 Kg/cm ² , preferably 5 Kg/cm ² or more higher than the Young's modulus of the tape-like material (usually 0.5 to 2 Kg/cm ² ). be.

If the width of the cured material layer is less than 0.5 μm, it will not be effective in reinforcing the ends of the tape-like object, and the objective is that the Young's modulus of the cured material layer is not higher than the main body of the tape-like object by 1.5 Kg/cm ² or more. The effect of preventing end tearing and breakage cannot be obtained.

<Effects of the Invention> The double-sided adhesive tape of the present invention is a double-sided adhesive tape in which a pressure-sensitive adhesive is formed on the surface of a releasable tape, and a cured material layer is provided on both ends of a tape-like product. are stacked on top of each other, so when unwinding from a roll tape, the double-sided adhesive tape can be unwound smoothly without breaking from the edge, tearing, and adhering to the back of the peelable tape. has.

Note that the term "Young's modulus" used in the claims and text is defined by setting the sample in a tensile tester with a distance between chucks of 10 mm and at a tensile speed of 300 mm/min.
The stress-strain curve is obtained by pulling it, and the stress at the intersection of the tangent to the rising edge of this curve and 100% elongation is converted into a value per unit area.

<Example> Examples of the present invention will be shown below.

Example 1 An acrylic pressure-sensitive adhesive composition was coated to a thickness of 50 μm on the surface of a releasable film made by coating both sides of glassine paper with a silicone release treatment agent, and wound 20M around the surface of a paper tube. A master roll of tape was prepared, which was cut into a width of 19 mm, and a tape roll formed by overlapping a tape-like material formed by forming a film of pressure-sensitive adhesive on the surface of the releasable tape was obtained.

Next, 2 g of benzophenone and 5 g of tetraethylene glycol dimethacrylate were added to 43 g of toluene.
and 50 g of an aqueous solution containing 3% by weight of polyethylene glycol alkyl phenyl ether (HLB16) and 2% by weight of dialkyl sulfone succinic acid ester sodium, and prepare an emulsified aqueous dispersion by high-speed stirring. .

After applying 0.2 g (solid content) of the aqueous dispersion to each side of the tape roll, the mixture was irradiated with a 400 W mercury lamp from an irradiation distance of 10 cm for 15 seconds to obtain a double-sided adhesive tape of the present invention.

When the tape roll was rewound and tested before irradiation, there was no tearing of the tape, but stringing occurred at the edges, and the end shape of the tape was significantly deformed. Although it was not possible to obtain an adhesive area, when the tape of the present invention was tested for unwinding, it was possible to unwind the tape without stringing.

The width of the cured layer integrally formed on the double-sided adhesive tape of the present invention was 50 μm, and the Young's modulus was 15 Kg/cm ² .

Example 2 A solution consisting of 2 g of benzophenone, 5 g of tetraethylene glycol dimethacrylate, and 100 g of toluene is prepared.

After applying 0.2 g (solid content) of this solution to each side of the tape roll of Example 1, the same procedure as in Example 1 was carried out to obtain a double-sided adhesive tape of the present invention.

The tape before irradiation was stringy as described above and an effective adhesive area could not be obtained, but the tape of the present invention could be rewound without stringing.

The width of the cured layer integrally formed on the double-sided adhesive tape of the present invention was 100 μm, and the Young's modulus was 18 Kg/cm ² .

Claims (1)

[Claims] 1. A tape-like material formed by forming a film of a pressure-sensitive adhesive is superimposed on the surface of a removable tape, and a tape-like material formed by forming a film of a pressure-sensitive adhesive is superimposed on both ends of the tape-like material. A double-sided adhesive tape characterized by integrally forming a narrow cured material layer with a high Young's modulus. 2. The double-sided adhesive tape according to claim 1, wherein the Young's modulus of the cured material layer is at least 1.5 Kg/cm ² higher than that of the tape-like material. 3. The double-sided adhesive tape according to claim 1, wherein the width of the cured material layer is at least 0.5 μm.