JP2002003799A - Adhesive sheets - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive sheet that has good adhesion to a wide variety of adherends from those having polarity to non-polarity without occurrence of lifting or peeling, particularly obtain a photopolymerization type pressure- sensitive adhesive that can be produced in the non-solvent system. SOLUTION: The objective adhesive sheets characteristically have the adhesive strength of >=7 N/20 mm (in 300 mm/min peeling rate and 180 deg. peel) and the adhesive strength in low-speed peeling of 5N/20 mm (in 1 mm/min peeling rate and 90 deg. peel).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive sheet (tape, sheet, etc.) provided with a pressure-sensitive adhesive on one or both sides of a substrate. More specifically, the present invention relates to adhesive sheets having good adhesive properties to a non-polar surface such as a polyolefin resin.

[0002]

2. Description of the Related Art In recent years, pressure-sensitive adhesives have become required to adhere to a wide variety of adherends due to the diversification of adherends. And good adhesion to the adherend having such a polarity.

[0003] Also, its use has been diversified. For example, a pressure-sensitive adhesive which does not float or peel off has been desired for use in fixing a name plate having a high repulsive force to a curved adherend. .

On the other hand, a pressure-sensitive adhesive is prepared by solution polymerization of a monomer mixture containing an alkyl acrylate monomer as a main component in an acrylic resin, and a rubber-based adhesive is dissolved in an organic solvent in a rubber resin. It has been adjusted by doing. However, these solvent-type pressure-sensitive adhesives have an environmental problem in that the solvent is volatilized at the time of coating, and in consideration of air pollution and environmental problems, it is possible to produce a pressure-sensitive adhesive tape without a solvent. The polymerizable pressure-sensitive adhesive is particularly advantageous in environmental and safety aspects.

However, in the case of photopolymerizable pressure-sensitive adhesives, it is difficult to improve the adhesive properties of the acrylic polymer alone, and concomitant use of a tackifier has been studied. Since the tackifier generally acts as a chain terminator for the photopolymerization reaction, the use of the tackifier inhibits the polymerization and causes, for example, a reduction in the molecular weight of the acrylic polymer, causing a decrease in the adhesive strength and cohesive strength.

For this reason, it is desirable to use a tackifier to be incorporated in the photopolymerizable adhesive, which has an effect of suppressing photopolymerization as little as possible. From this viewpoint, for example, Japanese Patent Application Laid-Open No. Hei. Discloses the use of a hydrogenated rosin ester-based tackifier, and JP-A-6-100837 proposes the use of a cumarone-indene-based tackifier.

[0007] These tackifiers hardly act as a chain transfer agent during photopolymerization and are certainly effective in suppressing polymerization inhibition. However, from the non-polar adherend to the polar adherend, Cannot sufficiently cope with the good adhesiveness of the above, and it is not always satisfactory.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional circumstances, the present invention provides an adhesive sheet which has good adhesion to various adherends from polar to non-polar, and does not float or peel off. An object of the present invention is to obtain an adhesive sheet provided with a photopolymerizable pressure-sensitive adhesive that can be manufactured.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the adhesive force (peeling speed 300 mm / min, 180 degree peel) was 7 N / 20 mm.
Above and low-speed peel adhesion (peel speed 1 mm / min, 90
Adhesive sheets characterized in that they have a degree of peel of 5 N / 20 mm or more, and when an adherend having a high repulsive force is adhered to an adherend having a curved surface, no floating or peeling occurs at the adhered portion. This led to the completion of the present invention.

[0010] In the present invention, α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added agent may be used as a tackifier incorporated in the photopolymerizable adhesive. By using rosin, a pressure-sensitive adhesive having good adhesion to various adherends from non-polar adherends to polar adherends can be obtained, and polymerization inhibition caused by conventional chain transfer can be obtained. Without receiving, know that it is possible to form an adhesive sheet that satisfies the above specific performance,
The present invention has been completed.

That is, the present invention relates to an adhesive sheet in which a pressure-sensitive adhesive is provided on one or both surfaces of a substrate, and which has an adhesive force (peeling speed of 30) to a polypropylene resin.
An adhesive sheet characterized by having a peel strength (0 mm / min, 180-degree peel) of 7 N / 20 mm or more and a low-speed peel adhesive strength (peel speed of 1 mm / min, 90-degree peel) of 5 N / 20 mm or more (claim 1). It is related to.

In a preferred embodiment of the present invention,
The present invention relates to an adhesive sheet characterized in that the pressure-sensitive adhesive comprises an adhesive composition containing the following components a and b (claim 2). a) a main monomer 70 whose main component is an alkyl acrylate monomer whose alkyl group has an average of 1 to 14 carbon atoms
To 99% by weight, and a polar group-containing copolymerizable monomer 30 to 1
B) α, β-ethylenically unsaturated monocarboxylic acid-modified rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-modified rosin

As a further preferred embodiment, the present invention relates to an adhesive sheet wherein the component (b) is acrylated rosin (Claim 3). The intensity ratio of the absorption of stretching vibration of the acid carbonyl group is 0.02 to 0.8.
The present invention relates to the adhesive sheets (claim 4).

Further, the present invention relates to adhesive sheets (claim 5), wherein the pressure-sensitive adhesive comprises a photopolymerized adhesive composition.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In order to provide an adhesive sheet which does not float or peel off from a polyolefin resin, in the present invention, an adhesive force (peeling speed: 300 mm / min, 180 degree peel) is applied to a polypropylene resin. 7N / 20m
m, preferably 9 N / 20 mm or more, and a low-speed peel adhesive strength (peel speed of 1 mm / min, 90 degree peel) of 5 N /
It is characterized by having a length of at least 20 mm, preferably at least 6 N / 20 mm.

That is, according to the present invention, a phenomenon such as lifting or peeling from an adherend is an extremely slow peeling phenomenon, and a method for evaluating an adhesive force which has been generally performed conventionally (for example, JIS)
Z-1522) alone cannot be used to evaluate the peeling behavior at such a low speed at a peeling speed of 300 mm / min.
m / min, 90-degree peel) of 5 N / 20 mm or more ensures that there is no lifting or peeling for applications such as fixing a nameplate with high repulsion to a curved-shaped adherend. It was found.

The adhesive sheet in the present invention is not particularly limited as long as the adhesive property satisfies the above specified value, but in order to obtain good adhesive property, an adhesive containing the following two components as essential components is required. Desirably, it consists of a composition.
A) a main monomer 70 containing an alkyl acrylate monomer whose alkyl group has an average of 1 to 14 carbon atoms as a main component;
To 99% by weight, and a polar group-containing copolymerizable monomer 30 to 1
B) α, β-ethylenically unsaturated monocarboxylic acid-modified rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-modified rosin

Furthermore, these adhesive compositions are environmentally friendly,
From the viewpoint of safety and the like, a photopolymerization type that can be produced without a solvent is desirable.

The monomer mixture as the component a in the present invention comprises a mixture of a monomer having an alkyl acrylate monomer as a main component and a polar group-containing copolymerizable monomer.

Examples of the alkyl acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylate.
Isobutyl acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate Octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, (meth) acrylic acid The alkyl group such as lauryl has 1 to 14 carbon atoms
Can be used.

The polar group-containing copolymer monomers include:
Unsaturated acids such as (meth) acrylic acid, itaconic acid and 2-acrylamidopropanesulfonic acid, and hydroxyl-containing monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxymethyl acrylate are used.

The proportions of the monomer containing an alkyl acrylate monomer as a main component and the polar group-containing copolymerizable monomer are 70 to 99% by weight for the former and 30 to 1% by weight for the latter. It is particularly preferable that the former is 90 to 98% by weight and the latter is 10 to 2% by weight. Outside these ranges, favorable results cannot be obtained in terms of adhesive properties.

The α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added rosin as the component b in the present invention are as follows:
Α, β-ethylenically unsaturated monocarboxylic acid and / or dicarboxylic acid is added to rosin-based resin by Diels-Alder
It is obtained by adding by a reaction.

The rosin-based resin used in the present invention includes gum rosin, tall oil rosin, wood rosin, and their modified products or mixtures. Further, pure substances such as abietic acid obtained by purifying these rosin-based resins can also be used.

As the α, β-ethylenically unsaturated monocarboxylic acid used in the present invention, the conjugated diene contained in the molecule of the rosin-based resin is compared with that of Diels-Alde.
It has a double bond capable of reacting with r, and acrylic acid, methacrylic acid, crotonic acid, levulinic acid and the like can be used. Further, as the α, β-ethylenically unsaturated dicarboxylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride and the like can be used. These can be used alone or in combination of two or more.

As a method of adding an α, β-ethylenically unsaturated monocarboxylic acid and / or dicarboxylic acid to a rosin resin by a Diels-Alder reaction, a rosin resin is heated and melted, and α, β-ethylene is added thereto. This is achieved by adding the unsaturated monocarboxylic acid and / or dicarboxylic acid and continuing the heating. At this time, in order to prevent coloring of the reactive product, it is preferable to carry out the reaction under an inert gas stream such as nitrogen gas.

In the present invention, after the α, β-ethylenically unsaturated monocarboxylic acid and / or dicarboxylic acid is added to the rosin resin by the Diels-Alder reaction, hydrogenation or disproportionation may be performed.
The method is carried out by heating in the presence of a hydrogenation catalyst or a disproportionation catalyst used in a usual hydrogenation or disproportionation reaction of a rosin-based resin.

In the present invention, among such α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added rosin, ( 1) An acrylated rosin represented by the formula is preferred. For this, a commercially available product such as "KE-604" manufactured by Arakawa Chemical Industries, Ltd. can be used.

[0029]

Embedded image

By adding an α, β-ethylenically unsaturated monocarboxylic acid and / or dicarboxylic acid to a rosin-based resin in this manner, the polarity of the resin can be increased and the acid value can be increased. The acid value is not particularly limited, but is desirably 180 or more, preferably 200 or more (usually 350 or less).

When such α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added rosin is used, the compatibility with the acrylic polymer is improved, and the adhesive phase is improved. No appearance problems such as white turbidity occur. In addition, very good adhesion can be obtained to both non-polar and polar adherends. On the other hand, when rosin, rosin ester, hydrogenated rosin, etc. to which no α, β-ethylenically unsaturated monocarboxylic acid and / or dicarboxylic acid is added, good adhesion to various adherends is achieved. No power can be expected, the compatibility with the base polymer is poor, and the appearance is poor.

The amount of the α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added rosin used depends on the adhesive composition finally obtained and the polymerization of the same. The stretching vibration of the ester-derived carbonyl group (about 1700 cm ^-1 ) and the stretching vibration of the carboxylic acid-derived carbonyl group (about 1730 cm ^-1 ) obtained by FT-IR measurement of the pressure-sensitive adhesive obtained.
Is 0.05 to 0.8, preferably 0.05 to 0.8
It is preferable to mix them so as to be 0.5. When the strength ratio is less than 0.02, the amount of the α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added rosin used is small, and the polar and non-polar adherends are used. May not be able to satisfy the adhesive strength to the adhesive. On the other hand, if the strength ratio exceeds 0.8, the initial tack becomes poor, and a satisfactory pressure-sensitive adhesive may not be obtained.

In order to satisfy the intensity ratio obtained by the FT-IR measurement, when acrylated rosin is used,
The acrylated rosin is used in an amount of 2 to 60 parts by weight, preferably about 5 to 40 parts by weight, per 100 parts by weight of the component a.

In the present invention, when the adhesive composition is of a photopolymerization type in which polymerization is carried out by irradiation with light such as ultraviolet light, a photopolymerization initiator is added to rapidly initiate polymerization, and the photopolymerizable adhesive composition is added. It is preferable that The photopolymerization initiator that can be used in the present invention is benzoin methyl ether or benzoin isopropyl ether,
2,2-dimethoxy-1,2-diphenylethane-1-
Benzoin ethers such as on, substituted benzoin ethers such as anisole methyl ether, substituted acetophenones such as 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenyl-ketone; Substituted alpha-ketoles such as methyl-2-hydroxypropiophenone, aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride, 1-phenyl-
Photoactive oximes such as 1,1-propanedione-2- (o-ethoxycarbonyl) -oxime are used. These can be used alone or in combination of two or more.

These photopolymerization initiators are used in an amount of 0.01 to 5 parts by weight, preferably 0.1 to 3 parts by weight, based on 100 parts by weight of the monomer mixture of the component a.
If the amount of the photopolymerization initiator is less than 0.01 part by weight, the polymerization rate is reduced. If the amount exceeds 5 parts by weight, the molecular weight is reduced and the cohesion may be insufficient.

In addition to the above components a and b, the photopolymerizable adhesive composition may contain, as an optional component, a polyfunctional acrylate such as trimethylolpropane triacrylate, pentaerythritol tetraacrylate, -Ethylene glycol diacrylate, 1,
Bifunctional or higher functional polyvalent alkyl acrylate monomers such as 6-hexanediol diacrylate and 1,12-dodecanediol diacrylate may be used. The amount of the polyfunctional acrylate monomer varies slightly depending on the number of functional groups, but the insoluble fraction of the pressure-sensitive adhesive composition is 5 to 90%.
%, Preferably 10 to 70%, more preferably 20 to 50%.
% Is preferably added. When a polyfunctional acrylate monomer is used in such a range, even if a decrease in cohesive force is observed due to chain transfer to the tackifier, this is compensated for by the crosslinking effect of the monomer, and good cohesive force is maintained. The retention at room temperature is improved.

In the present invention, the desired photopolymerizable adhesive composition includes the above-mentioned monomer mixture of the component a and the α, β-component of the component b.
It contains an ethylenically unsaturated monocarboxylic acid-added rosin and / or an α, β-ethylenically unsaturated dicarboxylic acid-added rosin and a photopolymerization initiator. Preliminary polymerization can be carried out to some extent using a photopolymerization initiator.

In addition, various conventionally known additives such as a plasticizer, a softener, a filler, a pigment, and a dye can be appropriately compounded within a range that does not inhibit the photopolymerizability.

In the present invention, such a photopolymerizable adhesive composition is once coated on release paper and then
By irradiating ultraviolet rays of about 000 mJ / cm ² and performing photopolymerization, the pressure-sensitive adhesive itself can be obtained.

Instead of coating on a release paper, a synthetic resin film such as a polyester film or various base materials such as a fiber base material is used. Similarly, by photopolymerizing, an adhesive sheet in the form of a sheet or a tape can be obtained. The thickness of the adhesive layer at this time is arbitrary.

In the present invention, the above-mentioned adhesive composition is desirably used without a solvent by photopolymerization. However, the adhesive composition is polymerized by solution polymerization, emulsion polymerization or suspension polymerization using an aqueous medium, which is generally performed. It doesn't matter. As the thermal decomposition type polymerization initiator and emulsifier used at this time, conventionally well-known ones can be used. The α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added rosin of the component b may be mixed at the time of polymerization. Alternatively, it may be added to and mixed with the aqueous dispersion.

The polymer obtained by the above solution polymerization or emulsion polymerization is applied on a substrate by an appropriate method, and dried by hot air to remove the solvent, thereby providing a pressure-sensitive adhesive on the substrate. Thus, the adhesive sheet of the present invention can be obtained.

The reason why such excellent adhesive properties can be obtained is not necessarily clear, but the α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or the α, β-ethylenically unsaturated dicarboxylic acid-added rosin itself can be obtained. The high polarity and acid value increase the compatibility with the acrylic polymer, and in the presence of these rosins, the monomer mixture containing an alkyl acrylate monomer as a main component is photopolymerized and adhered to the polymer. It is presumed that the addition of the tackifier further improved the compatibility of the two and changed the flexibility of the skeleton of the acrylic polymer.

As described above, according to the present invention, the adhesive force (peeling speed 300 mm / min, 18
(0 degree peel) is 7 N / 20 mm or more, and low-speed peel adhesive strength (peeling speed 1 mm / min, 90 degree peel) is 5 N / 20.
Adhesive sheets characterized in that the adhesive sheets have a thickness of at least mm, so that they do not float or peel off for applications such as fixing nameplates with high repulsion to curved adherends. Can be provided. In particular, in the present invention, a monomer mixture containing an alkyl acrylate monomer as a main component is mixed with a photopolymerization initiator and a polyfunctional acrylate monomer together with α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or Since a specific amount of the rosin having an α, β-ethylenically unsaturated dicarboxylic acid added therein is included in the photopolymerization, the solvent can be produced without using a solvent, which is desirable from the viewpoint of environmental and safety aspects.

[0044]

Next, an embodiment of the present invention will be described in more detail. Hereinafter, “parts” means “parts by weight”.
The properties of the adhesive tape were evaluated by the following methods.

<Adhesive Strength> A sample tape was obtained by bonding a pressure-sensitive adhesive sheet to a 25 μm PET film.
(20 mm in width x 150 mm in length), which was pressed back and forth on a stainless steel plate and a polypropylene plate as an adherend by reciprocating it with a 2 kg metal roller once, and then allowed to stand at 23 ° C for 30 minutes or more. The sample was then cooled to 23 ° C.
The force required for peeling from the adherend was measured using a Tensilon type tensile tester under the conditions of a peeling speed of 300 mm / min and a 180 ° peel.

<Low-speed peeling adhesive force>
A sample tape was attached to a 5 μm PET film (width: 20 mm × length: 150 mm). The sample tape was pressed back and forth with a 2 kg metal roller once on a polypropylene plate, and then left at 23 ° C. for 30 minutes or more. did. Next, the sample was peeled at 23 ° C. at a peeling rate of 1 mm / min.
Under a condition of 90 ° peel, a force required for peeling from the adherend was measured using a Tensilon type tensile tester.

<Nameplate Fixing Property> A pressure-sensitive adhesive sheet bonded to a 0.4 mm-thick aluminum plate was used as a sample sample (width 20 mm × length 150 mm) and diameter 500 mm.
The sample was bonded at 23 ° C. with the length direction of the sample in the circumferential direction. Leave it at 23 ° C,
One week later, the presence or absence of floating of the aluminum plate was observed.

<IR spectrum (FT-IR ATR)
Method)> The IR spectrum was obtained from PerkinElmer's “Spec
trum2000FT-IR ", FT-IR ATR method, germanium 45 degree prism integration number: 16 times, resolution (R
esolution): 4.0 cm ^-1 , Gain: 1

The intensity ratio calculation was the height of the strength of the ester to the peak top of a peak of a straight line passing through 1660cm ^-1 ~1800cm ^-1 as illustrated in Figure 1 is the baseline 1730 cm ^-1 . In addition, 1700 cm ^-1
The straight line passing through the valley peak and the peak end of the peak was taken as the baseline, and the height up to the peak top was taken as the strength of the carboxylic acid. The strength ratio is: strength ratio = (carboxylic acid strength) /
(Strength of ester).

Example 1 95 parts of 2-ethylhexyl acrylate, acrylic acid 5
Part, 2,2-dimethoxy-1,2-diphenylethane-
0.05 part of 1-one and 0.05 part of 1-hydroxy-cyclohexyl-phenyl ketone are charged into a four-necked flask and exposed to ultraviolet light under a nitrogen atmosphere to partially photopolymerize, thereby containing an oligomer. A syrup (viscosity 3.0 Pa · s) was obtained. To 100 parts of the partially polymerized syrup, 0.2 parts of trimethylolpropane triacrylate and acrylated rosin (“K” manufactured by Arakawa Chemical Industries, Ltd.)
E-604 ": acid value 238) of 20 parts was uniformly mixed to prepare a photopolymerizable adhesive composition.

This adhesive composition was coated on a 25 μm-thick polyethylene terephthalate film substrate which had been subjected to a release treatment, and this adhesive composition was further subjected to a release treatment to a 25 μm-thick polyethylene terephthalate film. And irradiated with 3000 mJ / cm ^{2 of} ultraviolet light to carry out photopolymerization. FT-IR measurement of this pressure-sensitive adhesive composition showed that the ratio of absorption of stretching vibration of carboxylic acid to absorption of stretching vibration of ester was 0.19. Then 2
By cutting to a width of 0 mm, an adhesive tape having an adhesive layer thickness of 50 μm was obtained.

Example 2 An adhesive tape was produced in the same manner as in Example 1 except that butyl acrylate was used instead of 2-ethylhexyl acrylate. The intensity ratio of the FT-IR spectrum of this pressure-sensitive adhesive composition was 0.14.

Comparative Example 1 The same procedure was carried out except that an acrylated rosin was not added to the partially polymerized syrup, and the same amount of hydrogenated coumarone-indene resin “S-Crystal N120-S” manufactured by Nippon Steel Chemical Co., Ltd. was added. An adhesive tape was produced in the same manner as in Example 1. The intensity ratio of the FT-IR spectrum of this pressure-sensitive adhesive composition was 0.01.

Comparative Example 2 Example 1 was repeated except that the same amount of perhydrogenated rosin ester resin “KE-656” manufactured by Arakawa Chemical Industries, Ltd. was added to the partially polymerized syrup without adding acrylate rosin. In the same manner as in the above, an adhesive tape was produced. FT of this pressure-sensitive adhesive composition
The intensity ratio of the -IR spectrum was 0.01.

Comparative Example 3 A partially polymerized syrup was prepared without adding acrylated rosin.
An adhesive tape was produced in the same manner as in Example 1 except that 0.2 part of tripropane triacrylate and 0.5 part of 1-hydroxy-cyclohexylphenyl-ketone were added.
The intensity ratio of the FT-IR spectrum of this pressure-sensitive adhesive composition was 0.01.

The adhesive properties of the adhesive tapes of the above Examples and Comparative Examples were examined, and the results are shown in Table 1 below.

[0057]

[Table 1]

From the above results, the adhesive tapes of the examples of the present invention have excellent adhesive strength to adherends from polar to non-polar, and in particular, the low-speed peel adhesive strength to propylene adherents satisfies a specific value or more. I understand that. In addition, it can be seen from this that it has good nameplate fixability. In contrast, Comparative Examples 1 and 2 did not satisfy the adhesive strength to the propylene adherend, and Comparative Example 3 did not satisfy the specific value of the adhesive strength to the propylene adherend, but the low-speed peel adhesive strength was remarkable. It is low and it is understood that this is inferior to the nameplate fixing property.

[Brief description of the drawings]

FIG. 1 is an example of an FT-IR spectrum of the adhesive sheets of the present invention.

Claims (5)

[Claims] 1. An adhesive sheet having a pressure-sensitive adhesive provided on one or both sides of a substrate, having an adhesive force (peeling rate of 300 mm / min, 180 degree peel) to polypropylene resin of 7 N / 20 mm or more. Adhesive sheets characterized by having a low-speed peel adhesive strength (peel speed of 1 mm / min, 90 degree peel) of 5 N / 20 mm or more. 2. The adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive comprises an adhesive composition containing the following components a and b. a) a main monomer 70 whose main component is an alkyl acrylate monomer whose alkyl group has an average of 1 to 14 carbon atoms
To 99% by weight, and a polar group-containing copolymerizable monomer 30 to 1
B) α, β-ethylenically unsaturated monocarboxylic acid-added rosin and / or α, β-ethylenically unsaturated dicarboxylic acid-added rosin 3. Adhesive sheets wherein the component b according to claim 2 is acrylated rosin. 4. The method according to claim 1, wherein the intensity ratio of the absorption of the stretching vibration of the ester carbonyl group to the absorption of the stretching vibration of the carboxylic acid carbonyl group is from 0.02 to 0.8 as measured by infrared absorption spectrum. Item 4. The adhesive sheet according to item 2 or 3. 5. The adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive comprises a photopolymerized adhesive composition.