JPH11209711A - Double-sided adhesive sheet - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent poor adhesion such as wrinkles and breakage by heating and bonding through a separator to an article having a large surface roughness, to provide excellent adhesion, and to provide a dry edge through a separator. Development of a double-sided adhesive sheet that can be easily visually recognized by the naked eye and that makes it easy to build a monitoring system using sensors and the like. SOLUTION: At least one of both surfaces of a support base material (2) has an adhesive layer (2, 3) composed of a pressure-sensitive adhesive layer (3),
Dimensional change by heating at 150 ° C for 30 minutes is 1.0%
A double-sided adhesive sheet wherein the surface of the pressure-sensitive adhesive layer is temporarily covered with a separator (4) made of the following translucent film. [Effect] The separator exhibits heat resistance and durability that withstands the heat bonding treatment, and the heat bonding treatment hardly causes the entire double-sided adhesive sheet to have poor adhesion such as wrinkles and breaks, and the main body of the double-sided adhesive sheet of the adhesive layer and the supporting substrate. Good adhesion treatment can be achieved even if the parts are of conventional specifications.

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 sheet which can be adhered without wrinkles or the like under heating while a separator is temporarily attached, and in which the end position of the adhesive layer in the bonded state can be easily determined.

[0002]

BACKGROUND OF THE INVENTION As an adhesive treatment method for articles having a large surface roughness, such as felt, cloth, and net-like objects, an adhesive layer including a pressure-sensitive adhesive layer temporarily covered with a separator is provided on both surfaces of a supporting substrate. Cut the double-sided adhesive sheet halfway through a punching blade and make a cutting line at the other part where the separator is left, remove the double-sided adhesive sheet part from the cut and form a dry edge part at the predetermined part such as the end of the separator After that, it is superposed on an article having a large surface roughness with the separator side as the front side, and heated and bonded through a press or the like, and then the separator is peeled off to allow the article having a large surface roughness to be sensed on the target adherend. 2. Description of the Related Art A method of performing pressure bonding via a pressure-bonding layer has been widely used.

Heretofore, as the double-sided adhesive sheet used in the above-mentioned method, a sheet in which a pressure-sensitive adhesive layer is temporarily covered with a transparent separator has been known. However, when the heat treatment is performed through a separator to melt or soften the adhesive layer on the article side and to flow the adhesive in the article having a large surface roughness so as to express a strong adhesive force, wrinkles and breaks are generated. There has been a problem that bonding failure occurs frequently. In addition, careful observation of the dry edge portion by the naked eye through the separator is required, and the visibility is poor, and monitoring with a sensor or the like requires a high-performance sensor or the like.

[0004]

SUMMARY OF THE INVENTION The present invention is directed to a method for bonding a product having a large surface roughness to a product having a large surface roughness by means of a heat bonding process through a separator.
Another object of the present invention is to develop a double-sided adhesive sheet that allows the dry edge portion to be easily visually recognized by the naked eye via a separator, and that enables easy construction of a monitoring system using a sensor or the like.

[0005]

According to the present invention, at least one of the surfaces of a supporting substrate has an adhesive layer composed of a pressure-sensitive adhesive layer,
A double-sided adhesive sheet characterized in that the surface of the pressure-sensitive adhesive layer is temporarily covered with a separator made of a translucent film having a dimensional change rate of 1.0% or less by heating at 30 ° C. for 30 minutes. Things.

[0006]

According to the double-sided adhesive sheet of the present invention, even if the separator exhibits heat resistance and durability to withstand the heat-bonding treatment and is subjected to heat-bonding treatment to an article having a large surface roughness via the separator, the double-sided adhesive sheet can be used. Adhesive defects such as wrinkles and breaks are unlikely to occur throughout. As a result, the adhesive layer and the body portion of the double-sided adhesive sheet of the supporting substrate can be satisfactorily adhered to the conventional specifications. In addition, the dry edge portion can be easily visually recognized by the naked eye via the separator, and the necessity of a high-performance sensor or the like for constructing a monitoring system can be avoided.

[0007] In the above, measures to prevent the occurrence of adhesion failure during the heat bonding process can be taken also through an adhesive layer or a support base material. In that case, however, a new device is required for the adhesive layer or the support base material. On the other hand, by increasing the thickness of the supporting substrate, heat resistance and durability that can withstand the heat bonding treatment can be imparted. However, an increase in the thickness of the supporting base material causes an increase in the thickness of the adhesive sheet, which is unsuitable for narrow gap bonding applications, and an increase in the thickness of the double-sided adhesive sheet causes an increase in stress against the adhesive sheet, and generally degrades the adhesive performance. I do.

Therefore, the conventional specifications can be applied to the main body of the double-sided adhesive sheet based on the solution via the separator according to the present invention, because the combination of the adhesive layer and the supporting base material based on the fixing force and the article to be adhered are different. All the conventional technologies accumulated regarding the types of the adhesive layers and the like can be used, and the technical significance is particularly large.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The double-sided adhesive sheet of the present invention has an adhesive layer at least one of which is formed of a pressure-sensitive adhesive layer on both sides of a supporting substrate, and has a dimensional change rate of 1.0 at a temperature of 150 ° C. for 30 minutes. % Of the pressure-sensitive adhesive layer is temporarily covered by a separator made of a translucent film of not more than 5%. An example is shown in FIG. 1 is an adhesive layer, 2 is a support substrate, 3 is a pressure-sensitive adhesive layer, and 4 is a separator.

Depending on the purpose of use, the support substrate may be a porous substrate made of, for example, paper, cloth or non-woven fabric, or a thin film made of a plastic film, foam, metal foil, or a laminate thereof. Can be used. A plastic film that can prevent the fluidized adhesive layer from penetrating is preferred from the viewpoint of the penetration of the adhesive layer into the adherend having a large surface roughness and the thin film property during the heat bonding treatment.

[0011] The material of the plastic film is not particularly limited, and an appropriate material can be used. Incidentally, as an example, polyethylene terephthalate (PE
T), polyesters such as polyethylene naphthalate and polyarylate, chloride-based polymers such as polyvinyl chloride and polyvinylidene chloride, olefin-based polymers such as polyethylene, polypropylene and ethylene-vinyl acetate copolymer, polycarbonate, polyamide, polyurethane and the like. A film made of an acrylic polymer, a styrene-based polymer, a polyvinyl alcohol-based polymer, a cellulose acetate-based polymer, or the like can be given.

Also, for example, heat-resistant polymers such as polyimide, polytetrafluoroethylene, polyetheretherketone, polyethersulfone, polymethylpentene, polyetherimide, polysulfone, polyphenylenesulfide, polyamideimide, polyesterimide, and aromatic polyamide. A film consisting of: can also be used as a supporting substrate. A support base made of the same kind of plastic as the separator, particularly a polyester such as PET, is preferred from the viewpoint of preventing the occurrence of poor adhesion.

The thickness of the supporting substrate may be determined as appropriate, but is generally from 1 to 500 μm, especially from 5 to
It is 400 μm, especially 10 to 300 μm. The support base material may be subjected to a known surface treatment such as a coating treatment with a primer or the like, a corona discharge treatment or a plasma treatment for the purpose of improving the adhesion to the adhesive layer.

The adhesive layer is provided on both sides of the supporting substrate, and at least one of the adhesive layers is a pressure-sensitive adhesive layer from the viewpoint of adhesive treatment properties and the like. An appropriate pressure-sensitive adhesive can be used for forming the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. Incidentally, examples of the pressure-sensitive adhesive include various pressure-sensitive adhesives such as rubber-based and acrylic-based, silicone-based and urethane-based, vinylalkylether-based and polyvinyl alcohol-based, polyvinylpyrrolidone-based and polyacrylamide-based, and cellulose-based adhesives. can give. The pressure-sensitive adhesive layer may be formed as a superposed layer of the pressure-sensitive adhesive layers made of the same or different kinds.

The adhesive layer provided on the other surface of the supporting substrate may be a pressure-sensitive adhesive layer of the same type or a different type from the pressure-sensitive adhesive layer on the back surface, or a superimposed layer thereof, or may be another type of adhesive layer. Is also good. The adhesive layer can be formed with an appropriate adhesive according to the related art. However, it is preferable to form the adhesive layer as a heat-activated adhesive layer from the viewpoint of workability of correcting the position of the sheet at the time of bonding and processing property of heat bonding. .

As the heat-activated adhesive layer, for example, an appropriate adhesive which is melted or softened by heating and exhibits adhesiveness, such as a hot-melt adhesive, can be used, and the type thereof is not particularly limited. Incidentally, any of the thermoplastic plastics exemplified as the above-mentioned supporting base material can be used for forming the heat-activated adhesive layer, and can also be used as a mixture of one or more plastics. In particular, a polyolefin-based adhesive such as an ethylene-vinyl acetate copolymer (EVA) can be preferably used for forming the heat-activated adhesive layer from the viewpoint of adhesive workability and the like.

In the above, the pressure-sensitive adhesive layer is formed, for example, by applying a pressure-sensitive adhesive in the form of a solution with an organic solvent, a dispersion or emulsion with water, or a mixture of monomer components, etc. onto a supporting substrate. It can be formed by an appropriate method such as a method of performing a heat drying treatment or a radiation irradiation treatment, or a method of transferring a pressure-sensitive adhesive layer formed on a separator according to the above method to a supporting substrate. In addition, the superimposed layer
It can be formed by a recoating method or a transfer superposition method.

The adhesive layer such as a heat-activated adhesive layer can be formed by an appropriate method such as a coating method according to the above, a coating method of a melt, or a heat lamination method of a film. In the latter lamination method, a film is formed by an extrusion method through a T-die or the like, and the film is laminated on a support substrate. Further, a film-like support substrate and an adhesive layer are formed by a two-layer extrusion method or the like. Alternatively, a method of laminating them can be adopted.

The thickness of the pressure-sensitive adhesive layer or the adhesive layer may be appropriately determined according to the desired adhesive strength.
~ 500μm, especially 5 ~ 450μm, especially 10 ~ 400μ
m. When forming the pressure-sensitive adhesive layer or the adhesive layer, if necessary, for example, natural or synthetic resins, tackifiers, plasticizers, softeners, glass fibers and glass beads, metal powder and calcium carbonate, clay and other Various additives such as fillers, pigments, colorants, and antioxidants made of inorganic powders and the like can be blended.

As a separator for temporarily covering the surface of the pressure-sensitive adhesive layer in the double-sided adhesive tape, a separator at 150 ° C., 30 ° C.
A translucent film having a dimensional change rate of 1.0% or less, preferably 0.8% or less, particularly 0.7% or less by heating for one minute is used. Thereby, it is possible to prevent the double-sided adhesive tape from undergoing a large dimensional change at the time of the heat-bonding treatment via the separator to cause poor adhesion such as wrinkles, breakage, damage, and the like. After adhering to the adherend 5, the dry edge portion 41 located on the back surface side of the separator 4 located on the front surface can be visually recognized satisfactorily. The dimensional change usually appears as heat shrinkage.

The preferable total light transmittance of the separator is 40 to 9 in view of the visibility of the dry edge portion and the like.
0%, especially 45-85%, especially 50-80%. Even if the separator is excellent in transparency, as in the case where the separator is excellent in opacity, the difference in the total light transmittance due to the transparency of the double-sided adhesive sheet is small and the visibility of the dry edge portion is poor. The visibility of the dry edge portion can be effectively used for checking the presence or absence of the main body of the double-sided adhesive sheet via the separator.

As the film forming the separator,
Those made of an appropriate plastic exemplified as the above-mentioned supporting base material can be used. Above all, a film made of polyester such as PET, polyimide, or the like can be preferably used from the viewpoint of the achievable dimensional change rate and the translucent processability.

The thickness of the film forming the separator is as follows:
Although it may be determined appropriately, it is generally set to 200 μm or less, particularly 25 to 150 μm, particularly 50 to 100 μm from the viewpoint of half-punching workability and handleability. The 10kgf / mm ² or more,
In particular, a film having a breaking strength of 12 to 30 kgf / mm ² , especially 15 to 27 kgf / mm ² is preferable from the viewpoint of half-punching workability and handleability.

The separator can be obtained by, for example, providing a coat layer made of an appropriate release agent such as a silicone-based, long-chain alkyl-based, or fluorine-based material on the surface of the film for forming the separator.

In the above, a separator film satisfying a predetermined dimensional change rate can be obtained by, for example, a method of performing an annealing treatment by heating. Control of the total light transmittance of the film, and therefore, translucency, can be achieved by a suitable method such as a method of blending an appropriate pigment such as titanium white or carbon black into a polymer forming the film and adjusting the blending amount. Can be performed.

The double-sided adhesive sheet according to the present invention can be applied to various adherends such as adherends having a large surface roughness in an appropriate form such as a sheet. It can be preferably used in the case of performing a heat bonding treatment.

[0026]

EXAMPLE 1 A PET film substrate having a thickness of 25 μm was coated on one side with a thickness of 70 μm.
A μm heat-activated adhesive film of EVA was laminated. On the other hand, a 60 μm-thick acrylic pressure-sensitive adhesive layer was applied to a separator obtained by surface-treating an annealed 75 μm-thick PET film having a total light transmittance of 75% with a silicone-based release agent. It was adhered to the other surface of the substrate to obtain a double-sided adhesive sheet.

Example 2 A double-sided adhesive sheet was obtained in the same manner as in Example 1, except that an annealed PET film having a thickness of 25 μm and a total light transmittance of 52% was used as a PET film.

Comparative Example 1 A double-sided adhesive sheet was obtained in the same manner as in Example 1 except that a PET film of a separator having a thickness of 75 μm and a total light transmittance of 92% was used without being subjected to an annealing treatment.

Comparative Example 2 A double-sided adhesive sheet was obtained in the same manner as in Example 1 except that a PET film as a separator, which was not annealed and had a thickness of 100 μm and a total light transmittance of 27%, was used.

Evaluation Test The following characteristics were examined for the separators or double-sided adhesive sheets obtained in the examples and comparative examples. Heat Shrinkage Rate (Dimensional Change Rate) The PET film for forming the separator was heated at 150 ° C. for 30 minutes, and the dimensional change rate (all heat shrinkage) was examined from the dimensional change before and after heating.

Appearance (poor adhesion), visibility (determination of dry edge portion) After half-cutting the double-sided adhesive sheet into a predetermined shape, the EVA heat-activated adhesive film was applied to black felt having an apparent thickness of about 3 mm. Polymerized through the side, pressed on the separator under the conditions of 150 ° C., pressure 2 kgf / cm ² , and time of 15 seconds to perform an adhesive treatment. The appearance and width of the obtained product were about 10 mm.
The dry edge portion was visually inspected to determine the judgment of the dry edge portion.

The above results are shown in the following table.

From the table, it can be seen that, in the examples of the present invention, the heat bonding treatment can be performed without adhesion failure via the separator, and the dry edge portion can be easily distinguished via the separator.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is an explanatory view of a bonding state.

[Explanation of symbols]

 1: adhesive layer 2: supporting substrate 3: pressure-sensitive adhesive layer 4: separator 5: adherend having large surface roughness

Claims (2)

[Claims] 1. A separator comprising a translucent film having at least one adhesive layer composed of a pressure-sensitive adhesive layer on both surfaces of a supporting substrate, and having a dimensional change rate of 1.0% or less when heated at 150 ° C. for 30 minutes. Wherein the surface of the pressure-sensitive adhesive layer is temporarily covered. 2. The double-sided adhesive sheet according to claim 1, wherein the supporting substrate is made of a polyester film, one of the adhesive layers is made of a heat-activated adhesive layer, and the separator is made of a polyester film having a total light transmittance of 40 to 90%. .