KR20190012228A - Pressure sensitive adhesive sheet - Google Patents

Abstract

Sensitive adhesive composition comprising a crosslinked silicone structure and a silicone-based pressure-sensitive adhesive composition comprising a silicone-based pressure-sensitive adhesive composition having a gel fraction of 40% or less and a probe tack of 0.9N or less as a ratio of insoluble components in toluene immersed in the silicone- A pressure-sensitive adhesive sheet is disclosed. This pressure-sensitive adhesive sheet does not stick to the surface of the pressure-sensitive adhesive layer, and when pressed with a finger or a palm, a stable and appropriate adhesive force is developed, so that alignment, reattachment and reattachment are easy, and furthermore, manufacturing and storage are easy.

Description

Pressure sensitive adhesive sheet

The present invention relates to a pressure-sensitive pressure-sensitive adhesive sheet which is stable in its proper adhesion when a surface of the pressure-sensitive adhesive layer is not tacky and is pressed with a finger or a palm, and is easy to align, reattach and re-peel.

BACKGROUND ART Conventionally, a pressure-sensitive adhesive sheet to which a finger, a palm or the like is pasted when an article is fixed, protected, or masked is widely used. However, since the pressure sensitive adhesive sheet in general has a sticky surface on the pressure sensitive adhesive layer, adhesion force is developed immediately upon contact with the adherend, making it difficult to align and reattach it. Also, wrinkles and air jam are likely to occur.

Thus, for example, Patent Document 1 discloses a pressure-sensitive adhesive sheet (hereinafter referred to as a "pressure-sensitive adhesive sheet") in which a core shell type adhesive layer is provided to provide an adhesive force by tacking at room temperature, . However, such a pressure-sensitive adhesive sheet is complicated in the process of forming the core-shell-type adhesive layer, and further, the adjustment of the pressure capable of breaking the shell layer is not simple.

Patent Document 2 discloses an adhesive tape substantially free from tackiness by using a pressure-sensitive adhesive containing a polyester having a polycarbonate structure in a pressure-sensitive adhesive layer and a polymer having a weight-average molecular weight of 20,000 or more and a polymer having a specific SP value. However, in such a pressure-sensitive adhesive, there is a possibility that an unintended adhesive force is developed in summer or in a high-temperature atmosphere. On the contrary, there is a fear that the pressure-sensitive adhesive may not be sufficiently adhered even in the winter or low temperature atmosphere.

Patent Document 3 discloses an acrylic curable pressure-sensitive adhesive composition which has a low initial tack and an adhesive strength to such an extent that reattachment to an adherend is possible at the time of adhesion, and which is firmly adhered by heat curing reaction after adhesion. However, in general, the adhesion strength due to the curing reaction is very high and it is difficult to re-peel off the adhesive tape, so that it can not be used for a masking tape or a protective sheet. In addition, it is necessary to store the adhesive tape at a low temperature before use.

Patent Document 1: JP-A-2012-102207 Patent Document 2: JP-A-11-61080 Patent Document 3: JP-A-7-216338

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure sensitive adhesive composition which is stable when a surface of the pressure sensitive adhesive layer is not tacky and is pressed with a finger or a palm and exhibits an appropriate adhesive force to facilitate alignment, reattachment and reattachment, Sheet.

DISCLOSURE OF THE INVENTION The present inventors have conducted intensive studies to achieve the above objects and found that a silicone adhesive layer having a specific gel fraction and a probe tack is very effective, .

That is, the present invention relates to a pressure-sensitive adhesive sheet comprising a crosslinked silicone structure and having a pressure-sensitive adhesive layer comprising a silicone-based pressure-sensitive adhesive composition having a gel fraction of 40% or less as measured by the following method and having a probe tack as measured by the following method: Is an adhesive sheet.

(Gel fraction)

The gel fraction is obtained by the following formula, which is the ratio of the insoluble component (insoluble component) when the silicone pressure sensitive adhesive composition is immersed in toluene for 1 day.

Gel fraction (%) = (C / A) x 100%

A: Initial mass of the silicone-based pressure-sensitive adhesive composition

C: Dry mass of the silicone pressure-sensitive adhesive composition after immersion in toluene (drying condition: 130 占 폚, 2 hours)

(Probe tip)

According to the probe test method according to JIS Z 0237, the force (probe tack) required to pull the circumferential probe having a diameter of 5 mm from the adhesive surface in the vertical direction is measured (load: 100 gf / cm ² , contact time: , Take-off speed 1 cm / sec).

When the pressure-sensitive adhesive sheet of the present invention has a large area, for example, the pressure-sensitive adhesive sheet of the present invention is temporarily fixed by lightly pressing the four corners with a finger or a palm. When the bonding position is deviated, the peeling is performed to fix the fixing. When the attachment position is correct, the whole is pressed and fixed securely. Particularly, in the pressure-sensitive adhesive sheet of the present invention, when the surface of the pressure-sensitive adhesive layer is not sticky, and when the pressure-sensitive adhesive layer is pressed with a finger or a palm, a stable and appropriate adhesive force is developed. Even the pressure-sensitive adhesive sheet can be easily attached to the correct position. In addition, when the four corners are fixed and the whole is uniformly pressed, wrinkles and air stagnation are hard to occur.

Further, since the pressure-sensitive adhesive sheet of the present invention uses a silicone-based pressure-sensitive adhesive for the pressure-sensitive adhesive layer, it is easy to manufacture compared to the core-shell type adhesive described in Patent Document 1, for example. In addition, the adhesive force is stable as compared with the specific pressure-sensitive adhesive described in Patent Document 2. Further, as compared with the thermosetting pressure-sensitive adhesive described in Patent Document 3, reattachment and re-peeling are easy, and furthermore, storage at room temperature is possible.

≪ Pressure sensitive adhesive composition &

The pressure-sensitive adhesive composition used in the present invention is a pressure-sensitive adhesive composition containing a silicone-based pressure-sensitive adhesive as a main component. The gel fraction of the pressure-sensitive adhesive composition is 40% or less, preferably 20% or more and 40% or less, and more preferably 25% or more and 35% or less. The tackiness of the pressure-sensitive adhesive composition is 0.9 N or less, preferably 0.5 N or less, and more preferably 0.2 N or less. When the gel fraction and the probe tack are within the specific range of the present invention, the surface of the adhesive layer is not sticky, and when pressed with a finger or a palm, a stable and appropriate adhesive force is developed. Specific measurement methods of the gel fraction and the probe tackiness are described in the column of Examples described later.

The swelling degree of the pressure-sensitive adhesive composition with respect to toluene is not particularly limited, but is preferably 200% or more and 650% or less, and more preferably 300% or more and 550% or less. Generally, the degree of swelling depends on the crosslinking density of the pressure-sensitive adhesive composition. When the cross-linking density is high, the three-dimensionally cross-linked polymer chain constituting the pressure-sensitive adhesive is hard to spread even when immersed in toluene, and the degree of swelling is lowered. On the other hand, when the crosslinking density is low, the polymer chain tends to spread and the degree of swelling increases. This degree of swelling is measured by the following method.

(Swelling degree)

Swelling degree is obtained by the following equation, which is the swelling rate due to absorption of toluene when the silicone pressure-sensitive adhesive composition is immersed in toluene at room temperature for 1 day.

Swelling degree (%) = ((B-A) / A) 100%

A: Initial mass of the silicone-based pressure-sensitive adhesive composition

B: Swelling mass of silicone-based pressure-sensitive adhesive composition after immersion in toluene

Specific examples of the silicone pressure-sensitive adhesive used in the present invention include MQ resin (M unit [(CH ₃ ) ₃ (CH ₃ ) ₂ SiO], a polydimethylsiloxane long chain polymer having a structure mainly composed of silicon raw material A polymer of a silicone resin having a three-dimensional structure having a structure _{composed of} [SiO _1/2 ] and Q unit [SiO _4/2 ]). Such a pressure-sensitive adhesive containing silicon raw material and MQ resin has superior adhesiveness to a silicone raw material group. Further, by changing the ratio of the silicon raw material to the MQ resin in the pressure-sensitive adhesive, it is possible to control basic adhesive properties such as adhesive force, holding force and tack. The silicone-based pressure-sensitive adhesives are categorized into an addition curing type and a peroxide curing type, depending on the curing mechanism (mechanism).

The addition curable silicone based pressure sensitive adhesive includes, for example, a main agent made of silicon raw material containing an alkenyl group, a MQ resin, and a crosslinking agent comprising a SiH group-containing polyorganosiloxane. Then, it is cured by heating under a platinum catalyst to effect crosslinking reaction. The silicon raw material containing an alkenyl group is typically a polyorganosiloxane having at least two alkenyl groups (for example, vinyl groups) bonded to silicon atoms in one molecule. The polyorganosiloxane containing a SiH group is typically a polyorganosiloxane having at least two hydrogen atoms bonded to silicon atoms in one molecule. Generally, in the addition curing type silicone pressure sensitive adhesive, the gel fraction tends to be lowered when the blending ratio of the MQ resin to the silicon raw material is increased, or when the content ratio of the alkenyl group in the silicon raw material (and / or MQ resin) is decreased . Generally, when the blending ratio of the MQ resin to the silicon raw material is increased or the crosslinking density of the pressure-sensitive adhesive is increased, the probe tack tends to be lowered. Therefore, as a method for obtaining a pressure-sensitive adhesive composition having a specific gel fraction and a probe tack using the addition-curable silicone based pressure-sensitive adhesive, for example, a blending ratio of an MQ resin to a silicon raw material, A pressure-sensitive adhesive layer, a pressure-sensitive adhesive layer, and a pressure-sensitive adhesive layer.

The peroxide-curable silicone-based pressure sensitive adhesive includes, for example, a subject made of silicone raw material containing no alkenyl group, and MQ resin. Then, a peroxide such as benzoyl peroxide is added as a curing agent, the solvent is removed, and the mixture is cured by heating at a high temperature. Generally, in a peroxide curable silicone pressure-sensitive adhesive, the gel fraction tends to be lowered when the compounding ratio of the MQ resin to the silicon raw material is increased or when the amount of the peroxide is decreased. Generally, the probe tack tends to be lowered by increasing the blending ratio of the MQ resin to the silicon raw material or increasing the crosslinking density of the pressure-sensitive adhesive. Therefore, as a method of obtaining a pressure-sensitive adhesive composition having a specific gel fraction and a probe tack using a peroxide curable silicone pressure-sensitive adhesive, there is a method of appropriately adjusting the blending ratio of the MQ resin to the silicon raw material and the addition amount of the peroxide. However, the pressure-sensitive adhesive composition used in the present invention is not limited to those obtained by such a method of adjustment.

Two or more silicone-based pressure-sensitive adhesives may be used in combination. In particular, the pressure-sensitive adhesive composition used in the present invention preferably comprises a cross-linked cured silicone adhesive. The cross-linking curing reaction of the silicone pressure-sensitive adhesive is usually carried out by heating. Depending on the kind of the pressure-sensitive adhesive and the curing agent, a condensation reaction or crosslinking curing with ultraviolet irradiation is also possible. In the case of using the addition curing type silicone pressure sensitive adhesive, the amount of the crosslinking agent comprising the SiH group-containing polyorganosiloxane may be appropriately adjusted.

A pressure-sensitive adhesive composition having a specific gel fraction and a probe tack of the present invention can be obtained by using a mixture of two or more kinds of silicone-based pressure-sensitive adhesives. Specifically, for example, a silicone-based tackifier having a relatively high gel fraction and a relatively high probe tack and a silicone-based tackifier having a relatively low gel fraction and a relatively low probe tackiness are mixed at an appropriate ratio and crosslinked and cured to obtain a gel fraction and a probe tack, Can be obtained. However, the pressure-sensitive adhesive composition used in the present invention is not limited to those obtained by such a method.

Additives may be added to the pressure-sensitive adhesive composition for the purpose of improving various properties. Specific examples of the additive include inorganic fillers such as carbon black and silica; polyorganosiloxanes such as silicone resin, polydimethylsiloxane and polydimethylphenylsiloxane; antioxidants such as phenol antioxidants and amine antioxidants; . However, it is necessary to appropriately select the kind or amount of the additive so that the effect of the invention is not impaired.

<Pressure Sensitive Adhesive Sheet>

The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer composed of the above-described pressure-sensitive adhesive composition, and is typically a pressure-sensitive adhesive sheet having a pressure- Sheet. Further, the pressure-sensitive adhesive sheet may be a baseless type pressure-sensitive adhesive sheet having no substrate. The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 1 to 100 占 퐉, more preferably 5 to 75 占 퐉, and particularly preferably 10 to 50 占 퐉.

The pressure-sensitive adhesive sheet of the present invention may be a double-sided pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer composed of the pressure-sensitive adhesive composition of the present invention on one side of the substrate and a pressure-sensitive adhesive layer composed of another pressure-sensitive adhesive composition on the other side.

The pressure-sensitive adhesive layer can be formed by subjecting the pressure-sensitive adhesive composition to a cross-link curing reaction. For example, a pressure-sensitive adhesive composition may be coated on a base material and crosslinked and cured by heating or condensation reaction or ultraviolet ray irradiation to form a pressure-sensitive adhesive layer on a substrate. The pressure-sensitive adhesive composition is applied on a release paper or other film, crosslinked and cured by heating or condensation reaction or ultraviolet ray irradiation to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is applied to one side or both sides of the substrate Or the like).

A solvent may be added to lower the viscosity of the pressure-sensitive adhesive composition upon application. Specific examples of the solvent include aromatic solvents such as toluene and xylene; aliphatic solvents such as hexane, octane and isoparaffin; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate and isobutyl acetate Based solvents, ether-based solvents such as diisopropyl ether and 1,4-dioxane.

The coating method is not particularly limited, and a known method may be used. Specific examples thereof include a coating method using a comma coater, a lip coater, a roll coater, a die coater, a knife coater, a blade coater, a rod coater, a kiss coater or a gravure coater, a screen coating, an immersion coating and a cast coating.

The substrate is not particularly limited, but a film-like substrate is preferable. Specific examples thereof include polyimide (PI), polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polyamideimide (PAI) A resin film of polyether sulfone (PES), polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and polyethylene (PE). Such a film can be used as a single layer or as a laminated film of two or more layers. The thickness of the substrate is not particularly limited, but is preferably 3 to 200 占 퐉, more preferably 5 to 160 占 퐉, and particularly preferably 12 to 130 占 퐉.

This adhesive (easy adhesion) treatment may be applied to the surface of the substrate on which the pressure-sensitive adhesive layer is provided, if necessary. Examples of the adhesion treatment include a primer treatment, a corona treatment, an etching treatment, a plasma treatment, a sand blast treatment, and the like.

The pressure-sensitive adhesive sheet of the present invention may be provided with a release liner. The release liner is for protecting the pressure-sensitive adhesive layer of the pressure-sensitive pressure-sensitive adhesive sheet. The release liner is peeled just before the application of the pressure-sensitive adhesive, and the pressure-sensitive adhesive sheet is attached to the adherend by exposing the pressure- The kind of the release liner is not particularly limited, and a known release liner can be used. Specific examples thereof include those obtained by subjecting the surfaces of base materials such as high-quality paper (high-quality paper), glassine paper, and synthetic resin films to a releasing agent treatment. For the release agent treatment, for example, a release agent such as a fluorine-substituted alkyl-modified silicone resin may be used. Particularly, as the release liner laminated on the silicone-based pressure-sensitive adhesive layer, it is preferable that the surface of the polyethylene terephthalate film is subjected to release treatment with a fluorine-substituted alkyl-modified silicone resin. When the adhesive property of the pressure-sensitive adhesive layer is low, a resin film not subjected to mold-releasing treatment may be used as a release liner. Specific examples thereof include a polyethylene terephthalate (PET) film, a polyethylene (PE) film and a polypropylene (PP) film.

Pressure-sensitive adhesive sheet of the present invention, for one minutes after pressing at a pressure of 0.03kg / cm ² (對) SUS adhesive strength is 1.9N / 20mm or less, and preferably 0.15N / 20mm or less, and more preferably from 0.25N / 20mm or less to be. The pressure condition of 0.03 kg / cm &lt; ² &gt; can be an index of the adhesive force generated only when the pressure-sensitive adhesive sheet is merely brought into contact with the adherend. That is, when the adhesive force of this test is low, the pressure-sensitive adhesive sheet does not exhibit an unnecessary adhesive force. Specific measurement methods are described in the column of Examples described later.

The pressure-sensitive adhesive sheet of the present invention is very useful for applications requiring only a stable adherence when the pressure-sensitive adhesive sheet is pressed with a finger or a palm without being adhered to only an adherend. For example, it is useful for applications such as protection, decoration, masking, fixing, and specific examples thereof include attaching to an adherend having a large area such as a wall, a window glass, a car, a train or the like without causing wrinkles or air clogging Applications, and fixing precision parts requiring precise alignment.

Example

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these examples. In the following description, &quot; part &quot; means &quot; part by mass &quot;.

&Lt; Example 1 &gt;

First, a plurality of prototypes (trial works) (I to IV) of the additional curing type silicone based pressure-sensitive adhesive solution were prepared. These plurality of prototypes can be obtained by appropriately changing the content ratio of the alkenyl groups in the silicon raw material (and / or MQ resin) of the blending ratio of the MQ resin to the silicon raw material so that the gel fraction, swelling degree, It is the prototype of the adhesive which adjusts the probe tack to show various values. In addition, these prototypes all use a common MQ resin. In the present embodiment, among the plurality of prototypes, the additional curing type silicone based pressure sensitive adhesive raw solution (I) having a gel fraction after cross-linking curing of 37%, a swelling degree of 399% and a probe tack of 0.48N was selected and used. Specifically, 100 parts of the additional curing type silicone pressure-sensitive adhesive solution (I) having a solid content concentration of 60 mass%, 100 parts of toluene as a diluting solvent and 0.9 part of a platinum catalyst as a curing catalyst were uniformly mixed to obtain a pressure-sensitive adhesive liquid (1).

Next, the pressure-sensitive adhesive solution (1) was applied to one surface of a 25 占 퐉 -top primer-treated polytetrafluoroethylene (PTFE) film so that the thickness of the pressure-sensitive adhesive layer after drying became 10 占 퐉, And then cured and dried at 130 DEG C for 2 minutes to form a pressure-sensitive adhesive layer. An untreated PET film having a thickness of 25 占 퐉 was peeled off as a release liner against the pressure-sensitive adhesive layer to obtain a pressure-sensitive adhesive sheet.

&Lt; Example 2 &gt;

A silicone-based pressure-sensitive adhesive additive solution (II) (solid content concentration of 60% by mass) having a gel fraction of 35%, a swelling degree of 358% and a probe tack of 0.06 N after cross-linking curing was selected from among the plurality of prototypes described above, I), the pressure-sensitive adhesive solution (2) was adjusted in the same manner as in Example 1 to produce an adhesive tape.

&Lt; Example 3 &gt;

Among the plurality of prototypes described above, the additional curing type silicone based pressure sensitive adhesive raw solution (III) (solid content concentration: 60% by mass) in which the gel fraction after crosslinking curing was 32%, the swelling degree was 384%, and the probe tack was 0.02N was selected, I), the pressure-sensitive adhesive liquid (3) was adjusted in the same manner as in Example 1 to produce an adhesive tape.

<Example 4>

Among the plurality of prototypes described above, the additional curing type silicone based pressure sensitive adhesive (IV) (solid content concentration: 60% by mass) having a gel fraction after cross-linking curing of 30%, a swelling degree of 350% and a probe tack of 0.01 N was selected, I), the pressure-sensitive adhesive liquid (4) was adjusted in the same manner as in Example 1 to produce an adhesive tape.

&Lt; Comparative Example 1 &

Sensitive adhesive sheet (5) was prepared in the same manner as in Example 1 except that an additional curing type silicone pressure-sensitive adhesive solution (trade name SD-4580, manufactured by Toray-Dow Corning Co., Ltd.) having a solid content concentration of 60 mass% .

&Lt; Comparative Example 2 &

Sensitive adhesive sheet (6) was prepared in the same manner as in Example 1, except that an additional curing type silicone pressure-sensitive adhesive solution (trade name SD-4570, manufactured by Toray-Dow Corning Co., Ltd.) having a solid content concentration of 60 mass% .

&Lt; Comparative Example 3 &

Sensitive adhesive sheet (7) was prepared in the same manner as in Example 1, except that an additional curing type silicone pressure-sensitive adhesive solution (trade name SD-4560, manufactured by Toray-Dow Corning Co., Ltd.) having a solid content concentration of 60 mass% .

&Lt; Comparative Example 4 &

Sensitive adhesive sheet (8) was prepared in the same manner as in Example 1 except that an additional curing type silicone pressure-sensitive adhesive solution (trade name KR-3701, manufactured by Shin-Etsu Chemical Co., Ltd.) having a solid content concentration of 60 mass% .

&Lt; Gel fraction and swelling degree of pressure-sensitive adhesive composition &gt;

The pressure-sensitive adhesive solutions (1) to (8) obtained in the examples and comparative examples were coated on a release liner so that the thickness after drying was 150 m. Then, it was heated in a drying oven and cured and dried to obtain a pressure-sensitive adhesive composition, which was used as a sample. The heating temperature at this time is 130 DEG C for 2 minutes.

The obtained sample was cut into a size of 50 mm x 50 mm and the release liner was peeled off to obtain a sample for measurement made of a pressure-sensitive adhesive composition on a sheet. The initial mass (A) (= mass of the pressure-sensitive adhesive composition before swelling) of the sample for measurement was measured. The sample for measurement was immersed in toluene at an amount of 250 times or more the initial mass (A) at room temperature (23 DEG C) for 24 hours to swell. After the immersion, the measurement sample was taken out, and the swollen mass (B) (= mass of the pressure-sensitive adhesive composition swollen with toluene) was measured. Further, the sample for measurement was dried in a dryer at 130 캜 for 2 hours to remove the absorbed solvent, and the dry mass (C) (= mass of the dried pressure-sensitive adhesive composition) was measured. The gel fraction and swelling degree of the pressure-sensitive adhesive composition were obtained by the following formula.

Gel fraction (%) = (C / A) x 100

Swelling degree (%) = ((B-A) / A) 100%

<Probe tack>

The pressure-sensitive adhesive sheets obtained in the examples and the comparative examples were subjected to a probe test using a probe tester TE-6001 manufactured by Tester Corporation and a circumferential probe having a diameter of 5 mm was cut in a direction perpendicular to the adhesive surface We measured the force required to pull it out (probe tip). The load at this measurement was 100 gf / cm ² , the contact time was 1 second, and the take-off speed was 1 cm / sec.

&Lt; Adhesion strength of SUS after pressing &gt;

The pressure-sensitive adhesive sheet cut to a width of 20 mm was placed on a polished SUS plate, pressed for 1 minute at the pressures (1) to (5) shown in Table 1, and pressed at 180 mm / minute using a tensile tester within 20 minutes. The force required to peel the tape at an angle of &lt; RTI ID = 0.0 &gt;

<Tactile>

The feel when touching the surface of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet obtained in Examples and Comparative Examples was evaluated according to the following criteria.

○: There was no stickiness.

B: There was some stickiness.

X: Very sticky.

The results of the above measurements are shown in Tables 1 and 2.

&Lt; Evaluation result &gt;

Table 1 and Example pressure sensitive adhesive sheet of 1-4 without sticking the surface of the adhesive layer, and a low initial adhesive strength and a press pressure of about 10kg / cm ² by proportion to the increase of the press pressure, as shown in Figure 1 The adhesive strength was increased. Therefore, it can be seen that the pressure-sensitive adhesive sheets of Examples 1 to 4 can easily control the adhesive force by the pressure of the finger or the palm of the hand.

On the other hand, in the pressure-sensitive adhesive sheets of Comparative Examples 1 to 4, since the gel fraction and the probe tack were too high, the surface of the pressure-sensitive adhesive layer became very sticky. In addition, the adhesive force was almost constant regardless of the pressing pressure. Therefore, it can be seen that it is difficult to control the adhesive force by the pressure force in the pressure-sensitive adhesive sheets of Comparative Examples 1 to 4.

Industrial availability

INDUSTRIAL APPLICABILITY The pressure-sensitive adhesive sheet of the present invention can be applied to applications requiring application to an adherend having a large area such as a wall, a window glass, an automobile, a train, etc. without causing wrinkles or air gaps, This is useful for fixing precision parts and the like.

Claims (7)

Sensitive adhesive layer having a pressure-sensitive adhesive layer containing a crosslinked silicone structure and comprising a silicone-based pressure-sensitive adhesive composition having a gel fraction of 40% or less as measured by the following method and having a probe tack of 0.9 N or less as measured by the following method Sheet.
(Gel fraction)
The gel fraction is obtained by the following formula, which is the ratio of the insoluble content when the silicone pressure-sensitive adhesive composition is immersed in toluene for one day.
Gel fraction (%) = (C / A) x 100%
A: Initial mass of the silicone-based pressure-sensitive adhesive composition
C: Dry mass of the silicone pressure-sensitive adhesive composition after immersion in toluene (drying condition: 130 占 폚, 2 hours)
(Probe tip)
According to the probe test method according to JIS Z 0237, the force (probe tack) required to pull the circumferential probe having a diameter of 5 mm from the adhesive surface in the vertical direction is measured (load: 100 gf / cm ² , contact time: , Take-off speed 1 cm / sec). The method according to claim 1,
Sensitive adhesive sheet wherein the gel fraction of the silicone-based pressure-sensitive adhesive composition is 20% or more and 40% or less. The method according to claim 1,
A pressure-sensitive adhesive sheet having a probe of a silicone-based pressure-sensitive adhesive composition of 0.5 N or less. The method according to claim 1,
Wherein the pressure sensitive adhesive sheet comprises an addition curing type silicone pressure sensitive adhesive to which a silicone pressure sensitive adhesive composition is crosslinked and cured. The method according to claim 1,
A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on at least one surface of a substrate. The method of claim 6,
Wherein the substrate is a resin film. The method according to claim 1,
Sensitive adhesive sheet having a SUS adhesive force of 1.9 N / 20 mm or less after being pressed for 1 minute at a pressure of 0.03 kg / cm ² measured by the following method.
(SUS adhesion after pressing)
The pressure-sensitive adhesive sheet cut to a width of 20 mm was placed on a polished SUS plate, pressed at a pressure of 0.03 kg / cm ² for 1 minute, and then subjected to a tape test at a rate of 300 mm / Measure the force required to exfoliate.