WO2017038307A1 - Pressure-sensitive adhesive sheet - Google Patents

Abstract

Provided is a pressure-sensitive adhesive sheet which has excellent shear performance and improved low-temperature resilience resistance. The present invention provides a pressure-sensitive adhesive sheet which includes a pressure-sensitive adhesive layer comprising a base polymer and at least one tackifier resin. The base polymer is a block copolymer of a monovinylaromatic compound with a conjugated diene compound. The content of the tackifier resin is 10-60 parts by weight per 100 parts by weight of the base polymer. The tackifier resin comprises a tackifier resin T_H having a softening point of 100ºC or higher. The content of the tackifier resin T_H is at least 10 parts by weight per 100 parts by weight of the base polymer. The pressure-sensitive adhesive layer has a tacky surface which has, in a ball tack test in a 0ºC environment, a tackiness property in terms of ball number of 4 or greater.

Description

Adhesive sheet

The present invention relates to an adhesive sheet.
This application claims priority based on Japanese Patent Application No. 2015-170076 filed on August 31, 2015 and Japanese Patent Application No. 2016-145330 filed on July 25, 2016, The entire contents of those applications are incorporated herein by reference.

Generally, a pressure-sensitive adhesive (also referred to as a pressure-sensitive adhesive; the same shall apply hereinafter) is in the form of a soft solid (viscoelastic body) in a temperature range near room temperature and has a property of easily adhering to an adherend by pressure. Taking advantage of such properties, pressure-sensitive adhesives are widely used in various industrial fields such as home appliances, automobiles, and office automation equipment as a bonding means with good workability and high adhesion reliability. A typical composition of the pressure-sensitive adhesive includes a composition containing a base polymer and a tackifying resin. As the base polymer, a polymer exhibiting rubber elasticity at room temperature can be preferably employed. For example, Patent Documents 1 to 3 describe an adhesive containing a styrene block copolymer such as a styrene isoprene styrene block copolymer or a styrene butadiene styrene block copolymer.

Japanese Patent Application Publication No. 2001-123140 Japanese Patent Application Publication No. 2001-342441 Japanese Patent Application Publication No. 10-287858

The pressure-sensitive adhesive having a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as described above (for example, a styrenic block copolymer) has a pressure-sensitive adhesive property (for example, adhesive strength and shear performance) at room temperature. When it is desired to improve, a blending technique for increasing the elastic modulus of the adhesive (hardening the adhesive) is adopted. However, such a design usually tends to greatly reduce the adhesive properties at low temperatures (typically repulsion resistance in a low temperature environment, also referred to as low temperature repulsion resistance). In the pressure-sensitive adhesive using the block copolymer as a base polymer, it is useful if the low-temperature repulsion resistance can be improved while maintaining the shear performance which is one of typical pressure-sensitive adhesive properties.

Therefore, the present invention is a pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer based on a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound (for example, a styrenic block copolymer), and has excellent shear performance. It is an object of the present invention to provide a pressure-sensitive adhesive sheet having improved low-temperature repulsion resistance.

According to this invention, an adhesive sheet provided with the adhesive layer containing a base polymer and tackifying resin is provided. The base polymer is a block copolymer of a monovinyl substituted aromatic compound and a conjugated diene compound. The content of the tackifying resin is 10 to 60 parts by weight with respect to 100 parts by weight of the base polymer. Further, the tackifying resin comprises a tackifier resin T _H having a softening point of more than 100 ° C.. Further, the content of the tackifier resin T _H is 10 parts by weight or more with respect to the 100 parts by weight of the base polymer. The pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer has characteristics of a ball number of 4 or more in a ball tack test under a 0 ° C. environment. The pressure-sensitive adhesive sheet exhibits improved low-temperature repulsion resistance while maintaining excellent shear performance in a configuration using a pressure-sensitive adhesive based on a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound. obtain.

In a preferred embodiment of the pressure-sensitive adhesive sheet disclosed herein, the tackifier resin contains a terpene phenol resin. And content of the said terpene phenol resin is 10 weight part or more with respect to 100 weight part of said base polymers. By comprising in this way, the adhesive sheet in which shear performance and low-temperature repulsion resistance were compatible is preferably implement | achieved. The content of the terpene phenol resin is preferably 10 to 30 parts by weight with respect to 100 parts by weight of the base polymer.

In a preferred embodiment of the pressure-sensitive adhesive sheet disclosed herein, the base polymer is a styrenic block copolymer. In a configuration using an adhesive having a styrene block copolymer as a base polymer, both the shear performance and the low-temperature repulsion resistance are preferably realized. In a more preferred embodiment, the styrene block copolymer has a styrene content of 20% by weight or less. In addition, the diblock ratio of the styrenic block copolymer is preferably 60% by weight or more.

Drawing 1 is a typical sectional view showing the composition of the adhesive sheet (double-sided adhesive sheet with a substrate) concerning one embodiment. FIG. 2 is a schematic cross-sectional view illustrating a configuration of a pressure-sensitive adhesive sheet (baseless double-sided pressure-sensitive adhesive sheet) according to another embodiment. FIG. 3 is a schematic cross-sectional view illustrating a configuration of an adhesive sheet (a single-sided adhesive sheet with a base material) according to another embodiment. 4 (a) and 4 (b) are explanatory views showing a method for conducting a low-temperature initial repulsion resistance test.

Hereinafter, preferred embodiments of the present invention will be described. Note that matters other than the matters specifically mentioned in the present specification and necessary for the implementation of the present invention are based on the teachings on the implementation of the invention described in the present specification and the common general technical knowledge at the time of filing. Can be understood by those skilled in the art. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.
In the following drawings, members / parts having the same action are described with the same reference numerals, and redundant descriptions may be omitted or simplified. In addition, the embodiment described in the drawings is schematically illustrated for clearly explaining the present invention, and does not accurately represent the size and scale of the pressure-sensitive adhesive sheet of the present invention actually provided as a product.

In this specification, the “pressure-sensitive adhesive” refers to a material that exhibits a soft solid (viscoelastic body) state in a temperature range near room temperature and has a property of easily adhering to an adherend by pressure as described above. . The adhesive here is generally complex elastic modulus E ^* (1 Hz) as defined in “C. A. Dahlquist,“ Adhesion: Fundamental and Practice ”, McLaren & Sons, (1966) P. 143”. <10 < ⁷ > dyne / cm < ² > material (typically a material having the above properties at 25 [deg.] C.). The pressure-sensitive adhesive in the technology disclosed herein can be grasped as a solid component of the pressure-sensitive adhesive composition or a constituent component of the pressure-sensitive adhesive layer.
The “base polymer” of the pressure-sensitive adhesive is the main component (that is, 50% by weight of the rubber-like polymer) of the rubber-like polymer (polymer exhibiting rubber elasticity in the temperature range near room temperature) contained in the pressure-sensitive adhesive. Component which occupies super).

In this specification, “a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound” refers to a monovinyl-substituted aromatic compound as a main monomer (more than 50% by weight of a copolymerization component; the same applies hereinafter). A polymer having at least one segment (hereinafter also referred to as “A segment”) and at least one segment having a conjugated diene compound as a main monomer (hereinafter also referred to as “B segment”). In general, the glass transition temperature of the A segment is higher than the glass transition temperature of the B segment. As a typical structure of such a polymer, a triblock copolymer (ABA triblock) having an A segment (hard segment) at each end of a B segment (soft segment), one A Examples thereof include a copolymer having a diblock structure composed of a segment and one B segment (diblock body having an AB structure).

In this specification, the “styrene block copolymer” means a polymer having at least one styrene block. The styrene block refers to a segment having styrene as a main monomer. A segment consisting essentially of styrene is a typical example of a styrene block as used herein. The “styrene isoprene block copolymer” refers to a polymer having at least one styrene block and at least one isoprene block (a segment having isoprene as a main monomer). Typical examples of styrene isoprene block copolymers are triblock copolymer (triblock body) having styrene blocks (hard segment) at both ends of isoprene block (soft segment), one isoprene block and one styrene. Examples thereof include a diblock copolymer (diblock body) composed of blocks. The “styrene butadiene block copolymer” refers to a polymer having at least one styrene block and at least one butadiene block (a segment containing butadiene as a main monomer).

In this specification, the “styrene content” of the styrenic block copolymer refers to the weight ratio of the styrene component to the total weight of the block copolymer. The styrene content can be measured by NMR (nuclear ceramic resonance spectrum method).
Further, the ratio of the diblock body in the styrene block copolymer (hereinafter sometimes referred to as “diblock body ratio” or “diblock ratio”) is determined by the following method. That is, a styrene block copolymer is dissolved in tetrahydrofuran (THF), and GS5000H and G4000H liquid chromatograph columns manufactured by Tosoh Corporation are connected in two stages, for a total of four stages, and THF is used as the mobile phase. Then, high performance liquid chromatography is performed under conditions of a temperature of 40 ° C. and a flow rate of 1 mL / min. The peak area corresponding to the diblock body is measured from the obtained chart. And the diblock body ratio is calculated | required by calculating the percentage of the peak area corresponding to the said diblock body with respect to the whole peak area.

<Structural example of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein (which may be in a long form such as a tape) may be, for example, in the form of a double-sided pressure-sensitive adhesive sheet having the cross-sectional structure shown in FIG. The double-sided pressure-sensitive adhesive sheet 1 includes a base material (for example, a plastic film or a non-woven fabric) 15, and a first pressure-sensitive adhesive layer 11 and a second pressure-sensitive adhesive layer 12 that are respectively supported on both surfaces of the base material 15. More specifically, the first pressure-sensitive adhesive layer 11 and the second pressure-sensitive adhesive layer 12 are provided on the first surface 15A and the second surface 15B (both non-peelable) of the base material 15, respectively. As shown in FIG. 1, the double-sided pressure-sensitive adhesive sheet 1 before use (before being attached to an adherend) is wound in a spiral shape with the front surface 21A and the back surface 21B overlapped with a release liner 21 which is a release surface. It can be in the form of In the double-sided pressure-sensitive adhesive sheet 1 in this form, the surface of the second pressure-sensitive adhesive layer 12 (second pressure-sensitive adhesive surface 12A) is peeled off by the front surface 21A of the release liner 21, and the surface of the first pressure-sensitive adhesive layer 11 (first pressure-sensitive adhesive surface 11A) is peeled off. The liner 21 is protected by the back surface 21B. Alternatively, the first adhesive surface 11A and the second adhesive surface 12A may be protected by two independent release liners.

The technique disclosed here is preferably applied to a double-sided pressure-sensitive adhesive sheet with a substrate as shown in FIG. 1, and also a double-sided pressure-sensitive adhesive sheet 2 having no base material (that is, having no base material) as shown in FIG. It can also be applied to. For example, as shown in FIG. 2, the double-sided pressure-sensitive adhesive sheet 2 before use is such that the first pressure-sensitive adhesive surface 11A and the second pressure-sensitive adhesive surface 11B of the substrate-less pressure-sensitive adhesive layer 11 are at least the surface (front surface) on the pressure-sensitive adhesive layer side. May be protected by release liners 21 and 22 that are release surfaces. Alternatively, the release liner 22 is omitted, and the release liner 21 having both sides of the release surface is used, and this and the adhesive layer 11 are overlapped and wound into a spiral shape, whereby the second adhesive surface 11B is released into the release liner. 21 may be in contact with the back surface of 21 and protected.

As shown in FIG. 3, the technology disclosed herein is also a single-sided adhesive type base including a base material 15 and a pressure-sensitive adhesive layer 11 supported on the first surface (non-peeling surface) 15 </ b> A of the base material. It can be applied to the pressure-sensitive adhesive sheet 3 with material. For example, as shown in FIG. 3, the pressure-sensitive adhesive sheet 3 before use is a release liner in which the surface (adhesive surface) 11 </ b> A of the pressure-sensitive adhesive layer 11 is at least the surface (front surface) on the pressure-sensitive adhesive layer side. 21 may be the protected form. Alternatively, the release liner 21 is omitted, and the first adhesive surface 11A is the second of the substrate 15 by winding the adhesive sheet 3 with the substrate using the substrate 15 having the second surface 15B as the release surface. It may be in a form protected against the surface 15B.

<Adhesive layer>
(Base polymer)
The pressure-sensitive adhesive layer disclosed herein contains a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as a base polymer. The monovinyl substituted aromatic compound refers to a compound in which one functional group having a vinyl group is bonded to an aromatic ring. A typical example of the aromatic ring is a benzene ring (which may be a benzene ring substituted with a functional group having no vinyl group (for example, an alkyl group)). Specific examples of the monovinyl substituted aromatic compound include styrene, α-methylstyrene, vinyl toluene, vinyl xylene and the like. Specific examples of the conjugated diene compound include 1,3-butadiene and isoprene. Such a block copolymer can be used for a base polymer individually by 1 type or in combination of 2 or more types.

The A segment (hard segment) in the block copolymer has a copolymerization ratio of the monovinyl-substituted aromatic compound (two or more can be used in combination) of 70% by weight or more (more preferably 90% by weight or more). It may be substantially 100% by weight). The B segment (soft segment) in the block copolymer has a copolymerization ratio of the conjugated diene compound (two or more can be used in combination) of 70% by weight or more (more preferably 90% by weight or more). It may be 100% by weight). According to such a block copolymer, a higher performance pressure-sensitive adhesive sheet can be realized.

The block copolymer may be in the form of a diblock body, a triblock body, a radial body, a mixture thereof, and the like. In the triblock body or radial body, it is preferable that an A segment (for example, a styrene block) is arranged at the end of the polymer chain. This is because the A segments arranged at the ends of the polymer chains are likely to gather to form a domain, thereby forming a pseudo cross-linked structure and improving the cohesiveness of the pressure-sensitive adhesive.
The block copolymer in the technique disclosed herein has a diblock ratio of 30% by weight or more (more preferably 40% by weight or more, more preferably 50%) from the viewpoint of adhesive strength (peel strength) to the adherend. % By weight or more, particularly preferably 60% by weight or more, typically 65% by weight or more) can be preferably used. From the viewpoint of peel strength, a block copolymer having a diblock body ratio of 70% by weight or more is particularly preferable. From the viewpoint of cohesiveness and the like, a block copolymer having a diblock body ratio of 90% by weight or less (more preferably 85% by weight or less, for example, 80% by weight or less) can be preferably used. For example, a block copolymer having a diblock ratio of 60 to 85% by weight is preferable, and a block copolymer having a diblock ratio of 70 to 85% by weight (for example, 70 to 80% by weight) is more preferable.

(Styrene block copolymer)
In a preferred embodiment of the technology disclosed herein, the base polymer is a styrenic block copolymer. For example, an embodiment in which the base polymer includes at least one of a styrene isoprene block copolymer and a styrene butadiene block copolymer is preferable. Among the styrene block copolymers contained in the pressure-sensitive adhesive, the proportion of styrene isoprene block copolymer is 70% by weight or more, the proportion of styrene butadiene block copolymer is 70% by weight or more, or styrene The total proportion of the isoprene block copolymer and the styrene butadiene block copolymer is preferably 70% by weight or more. In a preferred embodiment, substantially all (for example, 95 to 100% by weight) of the styrenic block copolymer is a styrene isoprene block copolymer. In another preferred embodiment, substantially all (for example, 95 to 100% by weight) of the styrenic block copolymer is a styrene butadiene block copolymer. According to such a composition, the effect of applying the technique disclosed here can be better exhibited.

The styrenic block copolymer may be in the form of a diblock body, a triblock body, a radial body, a mixture thereof, or the like. In a triblock body and a radial body, it is preferable that the styrene block is arranged at the terminal of the polymer chain. This is because the styrene blocks arranged at the end of the polymer chain are likely to gather to form a styrene domain, thereby forming a pseudo cross-linked structure and improving the cohesiveness of the pressure-sensitive adhesive. As the styrenic block copolymer used in the technology disclosed herein, the diblock ratio is 30% by weight or more (more preferably 40% by weight or more) from the viewpoint of adhesive strength (peeling strength) to the adherend. More preferably 50% by weight or more, particularly preferably 60% by weight or more, typically 65% by weight or more) can be preferably used. A styrenic block copolymer having a diblock ratio of 70% by weight or more (for example, 75% by weight or more) may be used. From the viewpoint of cohesion and the like, a styrenic block copolymer having a diblock ratio of 90% by weight or less (more preferably 85% by weight or less, for example, 80% by weight or less) can be preferably used. From the viewpoint of achieving a balance between cohesion and low-temperature repulsion resistance by applying the technology disclosed herein, a styrene block copolymer having a diblock ratio of 60 to 85% by weight is preferred, and 70 to 85% by weight. % (For example, 70 to 80% by weight) of a styrenic block copolymer is more preferable.

The styrene content of the styrenic block copolymer can be, for example, 5 to 40% by weight. From the viewpoint of cohesiveness, a styrene block copolymer having a styrene content of 10% by weight or more (more preferably more than 10% by weight, for example, 12% by weight or more) is preferable. From the viewpoint of peel strength, the styrene content is preferably 35% by weight or less (typically 30% by weight or less, more preferably 25% by weight or less), and 20% by weight or less (typically less than 20% by weight). For example, 18% by weight or less) is particularly preferable. A styrene block copolymer having a styrene content of 12% by weight or more and less than 20% by weight can be preferably employed from the viewpoint of better exerting the effect of applying the technology disclosed herein.

(Tackifying resin)
The pressure-sensitive adhesive layer disclosed herein contains a tackifying resin in addition to the base polymer. The tackifying resin is selected from various known tackifying resins such as petroleum resins, styrene resins, coumarone / indene resins, terpene resins, modified terpene resins, rosin resins, rosin derivative resins, and ketone resins. Species or two or more can be used.

Examples of petroleum resins include aliphatic (C5) petroleum resins, aromatic (C9) petroleum resins, aliphatic / aromatic copolymer (C5 / C9) petroleum resins, and hydrogenated products thereof ( Examples thereof include alicyclic petroleum resins obtained by hydrogenating aromatic petroleum resins.

Examples of styrenic resins include those based on homopolymers of styrene, those based on homopolymers of α-methylstyrene, those based on homopolymers of vinyltoluene, styrene, Those containing as a main component a copolymer containing at least two of α-methylstyrene and vinyltoluene in the monomer composition (for example, α-methylstyrene / styrene copolymer containing α-methylstyrene / styrene copolymer as the main component) Polymer resin) and the like.

As the coumarone-indene resin, a resin containing coumarone and indene can be used as a monomer component constituting the resin skeleton (main chain). Examples of monomer components that can be included in the resin skeleton other than coumarone and indene include styrene, α-methylstyrene, methylindene, and vinyltoluene.

Examples of the terpene resin include α-pinene polymer, β-pinene polymer, dipentene polymer and the like. Examples of the modified terpene resin include those obtained by modifying the terpene resin (phenol modification, styrene modification, hydrogenation modification, hydrocarbon modification, etc.). Specific examples include terpene phenol resins, styrene-modified terpene resins, hydrogenated terpene resins, and the like.

The above-mentioned “terpene phenol resin” refers to a polymer containing a terpene residue and a phenol residue. A copolymer of terpene and a phenol compound (terpene-phenol copolymer resin) and a terpene homopolymer or copolymer It is a concept that includes both a combination (terpene resin, typically unmodified terpene resin) and phenol-modified (phenol-modified terpene resin). Preferable examples of the terpene constituting the terpene phenol resin include monoterpenes such as α-pinene, β-pinene and limonene (including d-form, l-form and d / l-form (dipentene)).

Specific examples of the rosin resin include unmodified rosins such as gum rosin, wood rosin and tall oil rosin (raw rosin); modified rosins modified by hydrogenation, disproportionation, polymerization, etc. (hydrogenation) Rosin, disproportionated rosin, polymerized rosin, and other chemically modified rosins). Examples of rosin derivative resins include those obtained by esterifying unmodified rosin with alcohols (that is, rosin esterified products) and modified rosins (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) with alcohols. Rosin esters such as esterified products (ie, esterified products of modified rosin); Unmodified rosin or modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.) modified with unsaturated fatty acid Rosins; Unsaturated fatty acid-modified rosin esters obtained by modifying rosin esters with unsaturated fatty acids; Unmodified rosin, modified rosin (hydrogenated rosin, disproportionated rosin, polymerized rosin, etc.), unsaturated fatty acid-modified rosin or Rosin alcohols with reduced carboxyl groups in saturated fatty acid-modified rosin esters; unmodified rosin, modified Metal salts of rosins (particularly rosin esters) such as gin and various rosin derivatives; obtained by adding phenol to an rosin (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and thermal polymerization. Rosin phenol resin; and the like.

As a preferred embodiment, there may be mentioned an embodiment in which the pressure-sensitive adhesive layer contains one or more terpene phenol resins. For example, an embodiment in which 25% by weight or more (more preferably 30% by weight or more) of the total amount of the tackifying resin is a terpene phenol resin is preferable. Further, the amount of the terpene phenol resin in the entire tackifying resin can be about 70% by weight or less (for example, 60% by weight or less, typically 50% by weight or less). Alternatively, 50% by weight or more of the total amount of the tackifying resin may be a terpene phenol resin, and 80% by weight or more (for example, 90% by weight or more) may be a terpene phenol resin. All (for example, 95 to 100% by weight, further 99 to 100% by weight) may be terpene phenol resin. When the pressure-sensitive adhesive layer contains a terpene phenol resin as a tackifier resin, the content of the terpene phenol resin is suitably 5 parts by weight or more with respect to 100 parts by weight of the base polymer, preferably 10 parts by weight or more (for example, 10 weights). More than 15 parts by weight, more preferably 50 parts by weight or less, preferably 40 parts by weight or less, more preferably 30 parts by weight or less (for example, 25 parts by weight or less).

(Tackifying resin _TH )
PSA layer disclosed herein, as the tackifying resin, a softening point contains a tackifier resin T _H than 100 ° C.. From the viewpoint of aggregation property, the softening point of the tackifier resin _{T H,} preferably at least 120 ° C., more preferably at least 125 ° C., more preferably above 130 ° C., 135 ° C. or higher (e.g., 140 ° C. or higher) is especially preferred. Further, from the viewpoint of peel strength to the adherend, the softening point of the tackifier resin T _H, is suitably 200 ° C. or less, preferably 180 ° C. or less, more preferably 170 ° C. or less (e.g., 160 ° C. or less) is there.

Here, the softening point of the tackifier resin is defined as a value measured based on the softening point test method (ring ball method) defined in JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible, and is carefully filled so that no bubbles are formed in the ring placed on a flat metal plate. After cooling, cut off the raised part from the plane including the top of the ring with a slightly heated sword. Next, a supporter (ring stand) is put in a glass container (heating bath) having a diameter of 85 mm or more and a height of 127 mm or more, and glycerin is poured until the depth becomes 90 mm or more. Next, the steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample are immersed in glycerin so as not to contact each other, and the temperature of glycerin is maintained at 20 ° C. plus or minus 5 ° C. for 15 minutes. . Next, a steel ball is placed on the center of the surface of the sample in the ring, and this is placed in a fixed position on the support. Next, the distance from the upper end of the ring to the glycerin surface is maintained at 50 mm, a thermometer is placed, the center of the mercury bulb of the thermometer is set to the same height as the center of the ring, and the container is heated. The flame of the Bunsen burner used for heating is placed between the center and the edge of the bottom of the container so that the heating is even. It should be noted that the rate at which the bath temperature rises after reaching 40 ° C. after heating has started must be 5.0 plus or minus 0.5 ° C. per minute. The temperature at the time when the sample gradually softens and flows down from the ring and finally comes into contact with the bottom plate is read and used as the softening point. Two or more softening points are measured simultaneously, and the average value is adopted.

The tackifier resin T _H, using the above-described petroleum resins, styrene resins, coumarone-indene resins, terpene resins, modified terpene resins, rosin resins, rosin derivative resins, one or more of such ketone resin be able to. Of these, terpene resins, terpene phenol resins, rosin phenol resins, polymerized rosins, and esterified products of polymerized rosins are preferred.

As a preferable embodiment, there is an embodiment in which one or two or more terpene phenol resins are used as the tackifier resin _TH1 . For example, more than 25% by weight of the tackifier resin _{T H} (more preferably 30 wt% or more) is a preferred embodiment terpene phenol resin (tackifier resin _{T H1).} Furthermore, terpene phenol resin amount in the tackifier resin T _H is 70 wt% or less approximately (e.g. 60 wt% or less, typically 50 wt% or less) may be. Alternatively, the tackifier resin _T less than 50% by weight of _H is may be a terpene phenol resin (tackifier resin _{T H1),} 80 wt% or more (e.g. 90 wt% or more) terpene phenol resin (tackifier resin _{T H1} ) is a also good, substantially all of the tackifier resin _{T H} (for example, 95 to 100 wt%, or even 99 to 100 wt%) of a terpene phenol resin (tackifier resin _{T H1).} A terpene phenol resin having a softening point of 120 ° C. or higher and 200 ° C. or lower (typically 130 ° C. or higher and 180 ° C. or lower, eg, 135 ° C. or higher and 170 ° C. or lower) can be preferably used.

The ratio for which tackifying resin _TH1 accounts among all the tackifying resin contained in the adhesive layer disclosed here is not specifically limited. The ratio can be, for example, 30% by weight or more (typically 40% by weight or more), and can be, for example, 70% by weight or less (typically 60% by weight or less). Alternatively, substantially all (for example, 95 to 100% by weight, further 99 to 100% by weight) of the total tackifying resin may be the tackifying resin _TH1 .

Furthermore, the art disclosed herein, as the tackifier resin T _{H, (typically} terpene phenolic resin) tackifier resin T _H1 may be preferably implemented in a manner that includes a different tackifier resin T _H2 and. The softening point of the tackifier resin T _H2 is lower it is preferable than the softening point of the tackifier resin T _H1, about 10 ° C. or higher (e.g., 20 ° C. or higher) than the softening point of the tackifier resin T _H1 is more preferably lower . According to such an embodiment, for example, a pressure-sensitive adhesive sheet with better peel strength can be realized. From the viewpoint of making cohesion and peel strength compatible at a high level, a tackifying resin TH ₂ having a softening point of 100 ° C. or higher and lower than 120 ° C. can be preferably used. Especially, use of tackifying resin _TH2 whose softening point is 110 degreeC or more and less than 120 _degreeC is preferable.

As the tackifier resin _TH2 , the above-mentioned various tackifier resins (petroleum resin, styrene resin, coumarone / indene resin, terpene resin, modified terpene resin, rosin resin, rosin derivative resin, ketone resin, etc.) are appropriately used. It can be selected and used. The technique disclosed here can be preferably implemented in a mode in which the pressure-sensitive adhesive contains at least one of a petroleum resin and a terpene resin as the tackifying resin _TH2 . For example, a composition in which the main component of the tackifying resin TH ₂ (that is, a component occupying more than 50% by weight of the tackifying resin TH ₂ ) is a petroleum resin, a composition that is a terpene resin, a petroleum resin and a terpene resin A composition that is a combination, etc. can be preferably employed. From the viewpoint of adhesive strength and compatibility, an embodiment in which the main component of the tackifying resin _TH2 is a terpene resin (for example, α-pinene polymer or β-pinene polymer) is preferable. A terpene resin may be used for substantially all of the tackifying resin _TH2 (for example, 95% by weight or more).

As the adhesive layer tackifier resin _{T H} disclosed herein, if it contains a tackifier resin _{T H1} and the tackifier resin _{T H2,} the relationship between their _usage, T _H1: weight ratio of _{T H2} 25 : 75 to 70:30 (more preferably 30:70 to 60:40) is preferable. The technique disclosed here can be preferably implemented in an embodiment in which the pressure-sensitive adhesive contains more T _H1 than T _H2 as a tackifier resin. According to this aspect, a higher performance pressure-sensitive adhesive sheet can be realized.

Art disclosed herein, for example, as a tackifier resin _{T H,} the hydroxyl value may be preferably carried out in a manner containing 80 mg KOH / g or more (e.g. 90 mgKOH / g or higher) tackifying resin _{(T HO1).} The hydroxyl value of the tackifying resin _THO1 is typically 200 mgKOH / g or less, preferably 180 mgKOH / g or less (for example, 160 mgKOH / g or less). According to the pressure-sensitive adhesive containing the tackifying resin _THO1 , a higher-performance pressure-sensitive adhesive sheet can be realized. For example, a pressure-sensitive adhesive sheet that achieves a higher level of cohesion and other properties (for example, low-temperature repulsion resistance) can be realized.

Here, as the value of the hydroxyl value, a value measured by a potentiometric titration method defined in JIS K0070: 1992 can be adopted. The specific measurement method is as follows.
[Measurement method of hydroxyl value]
1. Reagent (1) As an acetylating reagent, about 12.5 g (about 11.8 mL) of acetic anhydride is taken, and pyridine is added thereto to make a total volume of 50 mL, and the mixture is sufficiently stirred. Alternatively, about 25 g (about 23.5 mL) of acetic anhydride is taken, and pyridine is added thereto to make a total volume of 100 mL, and the mixture is sufficiently stirred.
(2) As a measuring reagent, a 0.5 mol / L potassium hydroxide ethanol solution is used.
(3) Prepare toluene, pyridine, ethanol and distilled water.
2. Operation (1) About 2 g of a sample is accurately weighed in a flat bottom flask, 5 mL of an acetylating reagent and 10 mL of pyridine are added, and an air cooling tube is attached.
(2) The flask was heated in a bath at 100 ° C. for 70 minutes, then allowed to cool, and 35 mL of toluene was added as a solvent from the top of the condenser and stirred, and then 1 mL of distilled water was added and stirred to acetic anhydride. Disassemble. Heat again in the bath for 10 minutes to complete decomposition and allow to cool.
(3) Wash the cooling tube with 5 mL of ethanol and remove it. Next, 50 mL of pyridine is added as a solvent and stirred.
(4) Add 25 mL of 0.5 mol / L potassium hydroxide ethanol solution using a whole pipette.
(5) Potentiometric titration with 0.5 mol / L potassium hydroxide ethanol solution. The inflection point of the obtained titration curve is the end point.
(6) For the blank test, perform the above (1) to (5) without putting a sample.
3. Calculation The hydroxyl value is calculated by the following formula.
Hydroxyl value (mgKOH / g) = [(BC) × f × 28.05] / S + D
here,
B: Amount of 0.5 mol / L potassium hydroxide ethanol solution used for the blank test (mL),
C: The amount of 0.5 mol / L potassium hydroxide ethanol solution used for the sample (mL),
f: factor of 0.5 mol / L potassium hydroxide ethanol solution,
S: weight of the sample (g),
D: Acid value,
28.05: 1/2 of the molecular weight of potassium hydroxide 56.11,
It is.

As the tackifier resin _THO1 , those having a hydroxyl value of a predetermined value or more among the above-described various tackifier resins can be used alone or in appropriate combination. In a preferred embodiment, at least a terpene phenol resin is used as the tackifier resin _THO1 . The terpene phenol resin is preferable because the hydroxyl value can be arbitrarily controlled by the copolymerization ratio of phenol. The proportion of terpene phenol resin occupying in the tackifier resin T _HO1 is approximately 50 wt% or more (e.g. 80 wt% or more, and typically 90% by weight or more), more preferably, substantially the tackifier resin T _HO1 Further, it is more preferable that all (for example, 95 to 100% by weight, more preferably 99 to 100% by weight) is a terpene phenol resin.

Art disclosed herein is, when implemented in a manner of using a pressure-sensitive adhesive layer containing a tackifier resin T _HO1, the proportion of the tackifier resin T _HO1 of the total tackifying resin is not particularly limited. The said ratio can be 10 weight% or more (typically 20 weight% or more), for example, for example, can be 70 weight% or less (typically 60 weight% or less). Alternatively, substantially all of the tackifying resin (for example, 95 to 100% by weight, further 99 to 100% by weight) may be the tackifying resin _THO1 .

PSA layer disclosed herein is as a tackifier resin _{T H,} a hydroxyl value of 0 or 80 mg KOH / g of less than tackifier resin _{(T HO2)} may contain. Tackifier resin _{T HO2} may be used in place of the tackifier resin _{T HO1,} it may be used in combination with a tackifier resin _{T HO1.} As a preferred embodiment, the hydroxyl value is a tackifier resin _{T HO1} above 80 mg KOH / g, it includes embodiments comprising a tackifier resin _{T HO2.}

As the tackifier resin _THO2 , those having a hydroxyl value in the above range among the various tackifier resins described above can be used alone or in appropriate combination. For example, a terpene phenol resin having a hydroxyl value of 0 or more and less than 80 mgKOH / g, a petroleum resin (for example, C5 petroleum resin), a terpene resin (for example, β-pinene polymer), a rosin resin (for example, a polymerized rosin), a rosin A derivative resin (for example, esterified product of polymerized rosin) or the like can be used. In a preferred embodiment, at least a terpene phenol resin is used as the tackifying resin _THO2 . The terpene phenol resin is preferable because the hydroxyl value can be arbitrarily controlled by the copolymerization ratio of phenol. The proportion of terpene phenol resin occupying in the tackifier resin T _HO2 is approximately 50 wt% or more (e.g. 80 wt% or more, and typically 90% by weight or more) may be substantially the tackifier resin T _HO2 All (for example, 95 to 100% by weight, further 99 to 100% by weight) may be terpene phenol resin.

Art disclosed herein is, when implemented in a manner of using a pressure-sensitive adhesive layer containing a tackifier resin T _HO2, the proportion of the tackifier resin T _HO2 of the total tackifying resin is not particularly limited. The said ratio can be 10 weight% or more (typically 20 weight% or more), for example, for example, can be 70 weight% or less (typically 60 weight% or less). Alternatively, substantially all of the tackifying resin (for example, 95 to 100% by weight, further 99 to 100% by weight) may be the tackifying resin _THO2 .

The art disclosed herein, the tackifier resin _{T HO1} of the adhesive layer is a hydroxyl value 80 mg KOH / g or more (typically 80 ~ 160 mgKOH / g, for example 80 ~ 140mgKOH / g), a hydroxyl value 40 mg KOH / g It can be preferably implemented in an embodiment containing a combination of tackifying resin _{THO2 of} less than 80 mgKOH / g. In this _case, the relationship between the amount of _{T HO1} and _{T HO2,} for example, the weight ratio _{(T HO1:} T _HO2) is 1: 5 to 5: can be set to be 1, and 1: It is appropriate to set so as to be in the range of 3 to 3: 1 (for example, 1: 2 to 2: 1). As a preferred _{embodiment, T HO1,} T _HO2 is mentioned embodiment each a terpene phenol resin.

In one embodiment of the art disclosed herein, the tackifier resin _{T H} is as different tackifying resins and tackifying resin _{T HO1, T HO2,} has an aromatic ring and hydroxyl value is less than 30 mgKOH / g It may further contain a tackifying resin _THR1 . Examples of tackifying resins having an aromatic ring include the above-described aromatic petroleum resins, aliphatic / aromatic copolymer petroleum resins, styrene resins, coumarone-indene resins, styrene-modified terpene resins, phenol-modified terpene resins, A rosin phenol resin etc. are mentioned. Among these, those having a softening point of 120 ° C. or higher (preferably 130 ° C. or higher, eg 135 ° C. or higher) and a hydroxyl value of 30 mgKOH / g or lower (preferably less than 5 mgKOH / g, eg less than 1 mgKOH / g) It can be employed as _THR1 . Particularly preferred tackifying resins _THR1 include aromatic petroleum resins and styrene resins (for example, α-methylstyrene / styrene copolymer resins). In addition, the technique disclosed here can be implemented also in the aspect in which an adhesive layer does not contain tackifying resin _THR1 substantially.

In another embodiment of the PSA disclosed herein, the tackifier resin T _H as tackifier resin T _HO1, different tackifying resins and T _HO2, has an aromatic ring and isoprene units, terpene skeleton and It may contain a tackifier resin _THR2 substantially free of rosin skeleton. Here, the tackifying resin _THR2 substantially does not contain an isoprene unit, a terpene skeleton, and a rosin skeleton. The proportion of these structural parts (that is, the isoprene unit, the terpene skeleton, and the rosin skeleton) in the tackifying resin _THR2. Is less than 10% by weight in total (more preferably less than 8% by weight, even more preferably less than 5% by weight, for example, less than 3% by weight). The above ratio may be 0% by weight. In addition, the ratio of the isoprene unit, the terpene skeleton, and the rosin skeleton in the tackifying resin _THR2 can be measured by, for example, NMR (nuclear ceramic resonance spectrum method).

Examples of tackifying resins having an aromatic ring and substantially free of isoprene units, terpene skeletons and rosin skeletons include the above-mentioned aromatic petroleum resins, aliphatic / aromatic copolymer petroleum resins, and styrene resins. And coumarone-indene resin. Among these, those having a softening point of 120 ° C. or higher (preferably 130 ° C. or higher, eg, 135 ° C. or higher) can be adopted as the tackifying resin _THR2 . Particularly preferred tackifying resins _THR2 include aromatic petroleum resins and styrene resins (for example, α-methylstyrene / styrene copolymer resins). Although not particularly limited, as the tackifier resin _{T HR2,} for the same reason as the tackifier resin _{T HR1,} hydroxyl value 30 mgKOH / g or less (preferably less than 5 mgKOH / g, for example less than 1 mgKOH / g) of those Can be preferably employed. Therefore, as the tackifying resin _THR2 in the technology disclosed herein, those corresponding to the tackifying resin _THR1 can be preferably used. Similarly, as tackifying resin _THR1 in the technique disclosed here, what corresponds also to tackifying resin _THR2 can be used preferably. In addition, the technique disclosed here can be implemented also in the aspect in which an adhesive layer does not contain tackifying resin _THR2 substantially.

Further, the total amount of tackifier resin T _H for 100 parts by weight of the base polymer (i.e., the total amount of softening point 100 ° C. or more tackifier resins), from the viewpoint of shearing improved performance, it is appropriate to 10 parts by weight or more 20 parts by weight or more (for example, 25 parts by weight or more) is preferable. The upper limit of the content of the tackifier resin T _H for 100 parts by weight of the base polymer is 60 parts by weight. From the viewpoint of improving the low-temperature repulsion resistance, the content of the tackifier resin T _H for 100 parts by weight of the base polymer is preferably 50 parts by weight or less, more preferably 45 parts by weight or less (for example, 40 parts by weight or less).

Ratio of tackifier resin T _H relative to the total amount of tackifying resin, from the viewpoint of achieving both good balance and shear performance and low-temperature repelling resistance is suitably about 50 wt% or more, preferably 80 wt% Or more (for example, 90% by weight or more). The art disclosed herein, substantially all of the tackifying resin (e.g., 95-100% by weight, further 99 to 100% by weight) it may be preferably carried out in a manner which is tackifier resin T _H.

(Tackifying resin T _L )
The pressure-sensitive adhesive layer disclosed herein may include a tackifying resin _TL having a softening point of less than 100 ° C. The lower limit of the softening point of the tackifier resin _TL is not particularly limited. A softening point of 40 ° C. or higher (typically 60 ° C. or higher) can be used. The hydroxyl value and structure of the tackifier resin _TL (for example, the presence or absence of an aromatic ring, the presence or absence of an isoprene unit, the presence or absence of a terpene skeleton, the presence or absence of a rosin skeleton) are not particularly limited. Various tackifying resins (petroleum resin, styrene resin, coumarone / indene resin, terpene resin, modified terpene resin, rosin resin, rosin derivative resin, ketone resin, etc.) having a softening point of less than 100 ° C. What is necessary is just to select suitably and use.

In the technique disclosed herein, it is important that the total amount of the tackifier resin is in the range of 10 to 60 parts by weight with respect to 100 parts by weight of the base polymer. When the total amount of the tackifying resin is within the above range, the shear performance and the low-temperature repulsion resistance (typically low-temperature initial repulsion resistance) are compatible at a high level. The total amount of the tackifying resin is preferably 15 parts by weight or more, more preferably 20 parts by weight or more (for example, 30 parts by weight or more) with respect to 100 parts by weight of the base polymer from the viewpoint of improving the shear performance. Further, from the viewpoint of improving low-temperature repulsion resistance, the total amount of tackifying resin is preferably 50 parts by weight or less, more preferably 45 parts by weight or less (for example, 40 parts by weight or less) with respect to 100 parts by weight of the base polymer. .

(Isocyanate compound)
The pressure-sensitive adhesive composition disclosed herein may further contain an isocyanate compound. According to such a pressure-sensitive adhesive composition, a higher-performance pressure-sensitive adhesive sheet (for example, excellent in shear performance and low-temperature repulsion resistance) can be realized. As the isocyanate compound, polyfunctional isocyanate (refers to a compound having an average of two or more isocyanate groups per molecule, including those having an isocyanurate structure) can be preferably used. As this polyfunctional isocyanate, 1 type (s) or 2 or more types selected from the various isocyanate compounds (polyisocyanate) which have a 2 or more isocyanate group in 1 molecule can be used. Examples of such polyfunctional isocyanates include aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates and the like.

Specific examples of the aliphatic polyisocyanates include 1,2-ethylene diisocyanate; tetramethylene diisocyanate such as 1,2-tetramethylene diisocyanate, 1,3-tetramethylene diisocyanate, 1,4-tetramethylene diisocyanate; Hexamethylene diisocyanates such as hexamethylene diisocyanate, 1,3-hexamethylene diisocyanate, 1,4-hexamethylene diisocyanate, 1,5-hexamethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,5-hexamethylene diisocyanate; Examples include 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, and lysine diisocyanate.

Specific examples of the alicyclic polyisocyanates include isophorone diisocyanate; cyclohexyl diisocyanate such as 1,2-cyclohexyl diisocyanate, 1,3-cyclohexyl diisocyanate, 1,4-cyclohexyl diisocyanate; 1,2-cyclopentyl diisocyanate, 1,3 -Cyclopentyl diisocyanate such as cyclopentyl diisocyanate; hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and the like.

Specific examples of the aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, and 2,2′-diphenylmethane diisocyanate. 4,4′-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4′-diisocyanate, 2,2′-diphenylpropane-4,4′-diisocyanate, 3,3′-dimethyldiphenylmethane-4,4′-diisocyanate 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimeth Shi diphenyl-4,4'-diisocyanate, xylylene-1,4-diisocyanate, xylylene-1,3-diisocyanate.

Preferred examples of the isocyanate compound include polyfunctional isocyanates having an average of 3 or more isocyanate groups per molecule. Such a trifunctional or higher functional isocyanate is a difunctional or trifunctional or higher polymer (typically a dimer or trimer), a derivative (for example, a polyhydric alcohol and two or more polyfunctional isocyanates). Addition reaction product), polymer and the like. For example, diphenylmethane diisocyanate dimer or trimer, hexamethylene diisocyanate isocyanurate (trimer adduct of isocyanurate structure), reaction product of trimethylolpropane and tolylene diisocyanate, trimethylolpropane and hexamer Examples of the reaction product with methylene diisocyanate include polyfunctional isocyanates such as polymethylene polyphenyl isocyanate, polyether polyisocyanate, and polyester polyisocyanate. As commercial products of such polyfunctional isocyanates, trade names “Duranate TPA-100” manufactured by Asahi Kasei Chemicals Corporation, trade names “Coronate L”, “Coronate HL”, “Coronate HK” manufactured by Nippon Polyurethane Industry Co., Ltd. “Coronate HX”, “Coronate 2096” and the like.

When an isocyanate compound is used, the amount used is not particularly limited. For example, it is more than 0 parts by weight and 10 parts by weight or less (typically 0.01 to 10 parts by weight) with respect to 100 parts by weight of the base polymer. Can do. The amount of the isocyanate compound used relative to 100 parts by weight of the base polymer is preferably 0.1 parts by weight or more (typically 0.3 parts by weight or more, for example 0.5 parts by weight or more), and 10 parts by weight or less. It is appropriate to use 5 parts by weight or less (typically 3 parts by weight or less, for example, 1 part by weight or less). By using an isocyanate compound within such a range, a pressure-sensitive adhesive sheet having an excellent performance balance can be realized.

(Other ingredients)
The pressure-sensitive adhesive layer disclosed herein may contain one or more rubber-like polymers other than the base polymer as necessary as long as the effects of the present invention are not impaired. Such rubber-like polymers may be various polymers such as rubber-based, acrylic-based, polyester-based, urethane-based, polyether-based, silicone-based, polyamide-based, and fluorine-based polymers known in the field of pressure-sensitive adhesives. The technology disclosed herein is an embodiment in which the pressure-sensitive adhesive layer does not substantially contain a rubbery polymer other than the base polymer (for example, an embodiment in which the content per 100 parts by weight of the base polymer is 0 to 1 part by weight). It can be preferably implemented.

The pressure-sensitive adhesive composition disclosed herein (which may also be a pressure-sensitive adhesive layer) is optionally provided with a leveling agent, a crosslinking agent, a crosslinking aid, a plasticizer, a softening agent, a filler, and a colorant (pigment, dye). Etc.), an antistatic agent, an anti-aging agent, an ultraviolet absorber, an antioxidant, a light stabilizer, and the like. About such various additives, a conventionally well-known thing can be used by a conventional method. The pressure-sensitive adhesive disclosed herein contains substantially no liquid rubber such as polybutene (for example, the content per 100 parts by weight of the base polymer is 1 part by weight or less, and may be 0 part by weight). The embodiment can be preferably implemented.

In a preferred embodiment, in the pressure-sensitive adhesive layer, the total amount of the base polymer and the tackifying resin is 90% by weight or more of the total weight of the pressure-sensitive adhesive (that is, the weight of the pressure-sensitive adhesive layer constituted by the pressure-sensitive adhesive). The composition may occupy. For example, the total amount of the base polymer and the tackifying resin is 90% by weight or more (typically, for example, 95% by weight or more) and 99.8% by weight or less (typically Is preferably 99.5% by weight or less, for example.
In another preferred embodiment, the pressure-sensitive adhesive composition may be a composition substantially free of a chelate compound. Here, the chelate compound is, for example, a chelate compound of an alkaline earth metal oxide and a resin (alkylphenol resin or the like) having a functional group (hydroxyl group, methylol group or the like) capable of coordinating the oxide. Point to. The technology disclosed herein can be preferably implemented in such a manner that the pressure-sensitive adhesive composition does not contain such a chelate compound at all or the content of the chelate compound is 1% by weight or less. According to such an embodiment, a pressure-sensitive adhesive sheet with more excellent adhesive strength can be realized.

(Adhesive composition)
The form of the pressure-sensitive adhesive composition disclosed herein is not particularly limited. For example, the pressure-sensitive adhesive composition or pressure-sensitive adhesive in a form (solvent type) containing a pressure-sensitive adhesive (pressure-sensitive adhesive component) as described above in an organic solvent. Can be a pressure-sensitive adhesive composition in a form dispersed in an aqueous solvent (water-dispersed type, typically an aqueous emulsion type), a hot-melt type pressure-sensitive adhesive composition, and the like. From the viewpoints of coating properties and the degree of freedom in selecting a substrate, a solvent-type or water-dispersed pressure-sensitive adhesive composition can be preferably employed. From the viewpoint of realizing higher adhesive performance, a solvent-type adhesive composition is particularly preferable.

The solvent-type pressure-sensitive adhesive composition is typically prepared in the form of a solution containing each component described above in an organic solvent. The organic solvent can be appropriately selected from known or commonly used organic solvents. For example, aromatic compounds such as toluene and xylene (typically aromatic hydrocarbons); acetates such as ethyl acetate and butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane, cyclohexane, and methylcyclohexane Any one solvent selected from the group: halogenated alkanes such as 1,2-dichloroethane; ketones such as methyl ethyl ketone and acetylacetone; and a mixed solvent of two or more. Although not particularly limited, it is appropriate to prepare the solvent-based pressure-sensitive adhesive composition to have a solid content (NV) of 30% by weight or more (eg, 40% by weight or more), and 65% by weight or less (eg, 55% by weight). % Or less) is suitable. When NV is too low, the manufacturing cost tends to be high, and when NV is too high, handling properties such as coatability may be lowered.

(Formation method)
As a method for obtaining a pressure-sensitive adhesive sheet from the pressure-sensitive adhesive composition, various conventionally known methods can be applied. For example, a method (direct method) of forming a pressure-sensitive adhesive layer by directly applying (typically applying) the pressure-sensitive adhesive composition to a substrate and drying it can be preferably employed. Further, the pressure-sensitive adhesive composition is applied to a surface having good releasability (for example, the surface of a release liner, the back surface of a release support substrate, etc.) and dried to form a pressure-sensitive adhesive layer on the surface. Alternatively, a method (transfer method) of transferring the pressure-sensitive adhesive layer to the substrate may be employed.
Application of the pressure-sensitive adhesive composition can be carried out using a known or conventional coater such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, spray coater and the like. From the viewpoint of promoting the crosslinking reaction and improving the production efficiency, the pressure-sensitive adhesive composition is preferably dried under heating. For example, a drying temperature of about 40 ° C. or higher (for example, 50 ° C. or higher, further 70 ° C. or higher) and about 150 ° C. or lower (typically 120 ° C. or lower, more preferably 100 ° C. or lower) is preferably employed. be able to. The drying time is not particularly limited, but may be about several tens of seconds to several minutes (for example, within about 5 minutes, preferably about 30 seconds to 2 minutes). Then, you may provide an additional drying process as needed. The pressure-sensitive adhesive layer is typically formed continuously, but may be formed in a regular or random pattern such as a dot or stripe depending on the purpose and application.

(Adhesive layer thickness)
Although not particularly limited, the thickness of the pressure-sensitive adhesive layer is suitably about 4 μm or more (typically 20 μm or more, for example, 30 μm or more), and about 150 μm or less (typically 120 μm or less, for example, for example, 100 μm or less) is appropriate. From the viewpoint of improving low-temperature repulsion resistance, the thickness of the pressure-sensitive adhesive layer is preferably 30 μm or more, more preferably 40 μm or more, still more preferably 50 μm or more (for example, 60 μm or more, and further 75 μm or more). In the case of a double-sided pressure-sensitive adhesive sheet with a substrate, it is preferable that a pressure-sensitive adhesive layer having the above thickness is provided on each side of the substrate. The thickness of each pressure-sensitive adhesive layer may be the same or different. The pressure-sensitive adhesive layer is typically formed continuously, but may be formed in a regular or random pattern such as a dot or stripe depending on the purpose and application.

<Base material>
When the technology disclosed herein is applied to a double-sided PSA sheet with a substrate or a single-sided PSA sheet with a substrate, examples of the substrate include a polypropylene film, an ethylene-propylene copolymer film, a polyester film, and a polyvinyl chloride film. Foam sheets made of foams such as polyurethane foam, polyethylene foam, polychloroprene foam; various fibrous materials (natural fibers such as hemp and cotton; synthetic fibers such as polyester and vinylon; semi-finished materials such as acetate A woven fabric and a non-woven fabric (meaning including papers such as Japanese paper and fine paper)); metal foils such as aluminum foil and copper foil; etc. It can be appropriately selected and used depending on the application of the pressure-sensitive adhesive sheet. As the plastic film (typically a non-porous plastic film, which is a concept distinguished from a woven fabric or a non-woven fabric), any of an unstretched film and a stretched (uniaxially stretched or biaxially stretched) film is used. Can also be used. Moreover, surface treatment, such as application | coating of a primer and corona discharge treatment, may be given to the surface in which an adhesive layer is provided among base materials.

In a preferred embodiment, a nonwoven fabric (nonwoven fabric substrate) is used as the substrate. By using a nonwoven fabric base material, the low-temperature initial adhesiveness and shear performance tend to be improved. Examples of the nonwoven fabric used for the base material include nonwoven fabrics composed of pulps such as wood pulp, natural fibers such as cotton and hemp; polyester fibers such as polyethylene terephthalate (PET) fibers, rayon, vinylon, acetate fibers, polyvinyl Use non-woven fabric composed of chemical fibers (synthetic fibers) such as alcohol (PVA) fiber, polyamide fiber, polyolefin fiber, polyurethane fiber; non-woven fabric composed of two or more kinds of different materials; Can do. Especially, the nonwoven fabric comprised from a nonwoven fabric comprised from a pulp and hemp (for example, hemp pulp), a PET fiber, etc. are preferable from a viewpoint of the impregnation property of an adhesive, and repulsion resistance. The use of the nonwoven fabric substrate also contributes to an improvement in the flexibility and hand cutting property of the pressure-sensitive adhesive sheet.

As the nonwoven fabric (nonwoven fabric substrate), those having a basis weight of about 30 g / m ² or less (for example, 25 g / m ² or less, typically 20 g / m ² or less) can be preferably used. Such a nonwoven fabric having a basis weight is suitable for producing a pressure-sensitive adhesive sheet that is lightweight and excellent in adhesive performance. From the viewpoint of repulsion resistance, a nonwoven fabric having a basis weight of less than 18 g / m ² (for example, 16 g / m ² or less, typically 15 g / m ² or less) is preferable. From the viewpoint of improving the strength of the substrate itself, the basis weight is preferably 10 g / m ² or more (for example, 12 g / m ² or more, typically 13 g / m ² or more).

The bulk density of the nonwoven fabric substrate (which can be calculated by dividing the basis weight by the thickness) is suitably about 0.20 g / cm ³ or more, and 0.25 g / cm ³ or more (for example, 0.30 g / cm). ³ or more), preferably about 0.50 g / cm ³ or less, and preferably 0.40 g / cm ³ or less (eg, 0.35 g / cm ³ or less). When the bulk density is within the above range, the substrate itself has an appropriate strength, and good pressure-sensitive adhesive impregnation is obtained. From the viewpoint of repulsion resistance, it is particularly preferable to use a nonwoven fabric substrate having a bulk density of about 0.25 to 0.40 g / cm ³ (for example, 0.30 to 0.35 g / cm ³ ).

In addition to the constituent fibers as described above, the nonwoven fabric substrate contains resin components such as starch (eg, cationized starch), polyacrylamide, viscose, polyvinyl alcohol, urea formaldehyde resin, melamine formaldehyde resin, and polyamide polyamine epichlorohydrin. Can do. The resin component may function as a paper strength enhancer for the nonwoven fabric substrate. The strength of the nonwoven fabric substrate can be adjusted by using such a resin component as necessary. The nonwoven fabric substrate in the technology disclosed herein may contain other additives that are commonly used in the field of nonwoven fabric production, such as a yield improver, a drainage agent, a viscosity modifier, and a dispersant, as necessary. .

The thickness of the substrate can be appropriately selected according to the purpose, but generally it is appropriate to set it to approximately 2 μm or more (typically 10 μm or more), and 500 μm or less (typically 200 μm or less). It is preferable that When a nonwoven fabric is used as the substrate, the thickness of the nonwoven fabric substrate is suitably about 150 μm or less. From the viewpoint of sufficiently impregnating the entire substrate with the pressure-sensitive adhesive, the thickness is preferably 100 μm or less (for example, 70 μm or less). Moreover, when the handleability at the time of adhesive sheet preparation is considered, it is preferable that the said thickness is 10 micrometers or more (for example, 25 micrometers or more). From the viewpoint of repulsion resistance, the thickness is preferably 30 μm or more (for example, 35 μm or more, typically 40 μm or more), and 60 μm or less (for example, 50 μm or less, typically 45 μm or less). Is preferred. The nonwoven fabric substrate disclosed herein has at least two of the basis weight, thickness and bulk density in the above preferred ranges (for example, basis weight and thickness, more preferably all of basis weight, thickness and bulk density). It is preferable to satisfy. Thereby, an adhesive sheet in which a plurality of adhesive properties (for example, repulsion resistance, cohesiveness, peel strength, etc.) are highly balanced can be realized.

<Release liner>
A conventional release paper or the like can be used as the release liner, and is not particularly limited. For example, a release liner having a release treatment layer on the surface of a substrate such as a plastic film or paper, or a release liner made of a low adhesive material such as a fluorine-based polymer (polytetrafluoroethylene, etc.) or a polyolefin-based resin (polyethylene, polypropylene, etc.) Etc. can be used. The release treatment layer may be formed, for example, by surface-treating the substrate with a release treatment agent such as silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide.

<Characteristics of adhesive sheet>
The pressure-sensitive adhesive sheet disclosed herein has a characteristic that the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer has a ball number of 4 or more in a ball tack test (low temperature ball tack test) in an environment of 0 ° C. In other words, the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer has a ball tack of 4 or more in a ball tack test in an environment of 0 ° C. According to the pressure-sensitive adhesive sheet exhibiting a ball tack of a predetermined level or higher in a low-temperature environment, it adheres well to the adherend immediately after bonding, so peeling (turning or floating) due to lack of tack that tends to become noticeable in a low-temperature environment Is prevented. As a result, since the adhesive state with the adherend can be continuously maintained, excellent low-temperature repulsion resistance is exhibited. The pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer preferably has a characteristic of a ball number of 5 or more in the ball tack test, more preferably a characteristic of a ball number of 6 or more, and a ball number of 7 or more (for example, a ball number of 8 or 9). More preferably, it has the above characteristics. The low temperature ball tack test is performed by the method described in the examples described later.

The pressure-sensitive adhesive sheet disclosed herein may exhibit a low-temperature initial repulsion resistance in which a floating distance after 5 seconds is 15 mm or less in a low-temperature initial repulsion resistance test performed by a method described in Examples described later. . The pressure-sensitive adhesive sheet satisfying this characteristic is unlikely to peel off (turn over or float) in a low temperature environment. The floating distance in the low-temperature initial repulsion resistance test is preferably 5 mm or less, and more preferably 3 mm or less.

The pressure-sensitive adhesive sheet disclosed herein preferably has a holding time of 2 hours or more in a 40 ° C. shear performance evaluation test performed by applying a load of 500 g. Moreover, as for the adhesive sheet disclosed here, it is more preferable that the shift | offset | difference distance after 2 hours from the initial position in the said shear performance evaluation test is 5 mm or less. The pressure-sensitive adhesive sheet satisfying the above characteristics exhibits excellent holding power. The displacement distance is preferably 2 mm or less (for example, 1 mm or less, typically 0.5 mm or less, and further 0.3 mm or less), and more preferably 0.2 mm or less (further 0.1 mm or less). Particularly preferred. The shear performance evaluation test is performed by the method described in the examples described later.

The total thickness of the pressure-sensitive adhesive sheet disclosed herein is not particularly limited, and should be about 1000 μm or less (for example, 500 μm or less, typically 300 μm or less) from the viewpoints of thinning, lightening, and resource saving. Is preferred. Further, from the viewpoint of ensuring good adhesive properties, it is appropriate that the thickness is 50 μm or more (for example, 70 μm or more, typically 100 μm or more).

<Application>
The pressure-sensitive adhesive sheet disclosed herein is useful for joining between members in various OA equipment, home appliances, automobiles, and the like (for example, for fixing various parts in such products). In addition, since the pressure-sensitive adhesive sheet disclosed herein is excellent in low-temperature repulsion resistance, various materials in an environment that can be a low-temperature environment in winter such as a construction site (for example, an outdoor environment) or in a low-temperature space (for example, a refrigerator) Can be preferably used for joining and fixing. The pressure-sensitive adhesive sheet disclosed herein can be particularly preferably used in applications for fixing a decorative sheet used for decorating a building inner wall to the decorative sheet inner wall.

The matters disclosed by this specification include the following.
(1) A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer containing a base polymer and a tackifier resin,
The base polymer is a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound,
The content of the tackifying resin is 10 to 60 parts by weight with respect to 100 parts by weight of the base polymer,
The tackifying resin comprises a tackifier resin T _H having a softening point of above 100 ° C.,
The content of the tackifier resin T _H is 10 parts by weight or more with respect to the 100 parts by weight of the base polymer,
The pressure-sensitive adhesive layer is a pressure-sensitive adhesive sheet having a ball number 4 or more in a ball tack test under a 0 ° C. environment.
(2) The tackifier resin includes a terpene phenol resin,
Content of the said terpene phenol resin is an adhesive sheet as described in said (1) which is 10 weight part or more with respect to 100 weight part of said base polymers.
(3) The pressure-sensitive adhesive sheet according to (2), wherein the content of the terpene phenol resin is 10 to 30 parts by weight with respect to 100 parts by weight of the base polymer.
(4) The pressure-sensitive adhesive sheet according to any one of (1) to (3), wherein the base polymer is a styrenic block copolymer.
(5) The adhesive sheet according to (4), wherein the styrene block copolymer has a styrene content of 20% by weight or less.
(6) The pressure-sensitive adhesive sheet according to (4) or (5), wherein the diblock body ratio of the styrenic block copolymer is 60% by weight or more.

(7) The pressure-sensitive adhesive sheet according to any one of (1) to (6), wherein the base polymer contains at least one of a styrene isoprene block copolymer and a styrene butadiene block copolymer.
(8) The tackifier resin is at least one selected from the group consisting of petroleum resins, styrene resins, coumarone / indene resins, terpene resins, modified terpene resins, rosin resins, rosin derivative resins, and ketone trees. The pressure-sensitive adhesive sheet according to any one of (1) to (7) above.
(9) said tackifier resin T _H is terpene resins, terpene phenol resins, including rosin phenolic resins, at least one member selected from the group consisting of polymerized rosin and polymerized rosin ester, (1) to (8 ) The pressure-sensitive adhesive sheet according to any one of the above.
(10) wherein substantially all of the tackifying resin is a tackifier resin T _H, the pressure-sensitive adhesive sheet according to any one of the above (1) to (9).
(11) The pressure-sensitive adhesive sheet according to any one of (1) to (10), wherein the tackifier resin _TH includes two or more terpene phenol resins.
(12) said tackifier resin _{T H} has a softening point comprises a 120 ° C. or higher 200 ° C. or less of the terpene phenol resin, pressure-sensitive adhesive sheet according to any one of the above (1) to (11).
(13) said tackifier resin _{T H} comprises a terpene phenol resin as a tackifier resin _{T H1,} the low tackifier resin _{T H2} softening point than the adhesive imparting resin _{T H1,} the (1) - ( The pressure-sensitive adhesive sheet according to any one of 12).
(14) The pressure-sensitive adhesive sheet according to (13), wherein the tackifying resin _TH2 includes a terpene resin.
(15) the pressure-sensitive adhesive layer, as the tackifier resin _{T H,} a hydroxyl value comprises a tackifier resin _{T HO1} above 80 mg KOH / g, pressure-sensitive adhesive sheet according to any one of the above (1) to (14).
(16) the pressure-sensitive adhesive layer, a tackifier resin _{T H,} a hydroxyl value further comprises a tackifier resin _{T HO2} 0 to less than 80 mg KOH / g, pressure-sensitive adhesive sheet according to (15).
(17) The pressure-sensitive adhesive sheet according to any one of (1) to (16), wherein the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains an isocyanate compound.
(18) The pressure-sensitive adhesive sheet according to any one of (1) to (17), wherein the pressure-sensitive adhesive layer has a thickness of 30 μm or more.
(19) Any of the above (1) to (18), comprising: a base material; and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer as the pressure-sensitive adhesive layers supported on both surfaces of the base material, respectively. The pressure-sensitive adhesive sheet described in 1.
(20) The pressure-sensitive adhesive sheet according to (19), wherein the substrate is a plastic film or a nonwoven fabric.

Hereinafter, some examples relating to the present invention will be described. However, the present invention is not intended to be limited to the examples shown in the examples. In the following description, “parts” and “%” are based on weight unless otherwise specified. Each characteristic in the following description was measured or evaluated as follows.

(1) Low temperature ball tack test A set of test equipment (ball tack table, measuring balls, washed toluene, etc.) and a measurement sample (adhesive sheet) are allowed to stand in an environment of 0 ° C. for 1 hour, and in accordance with JIS Z0237 in the same environment. Accordingly, an inclined ball tack (an inclination angle of 30 degrees) was measured. The ball number of the largest ball held was recorded as the ball tack.

(2) Low-temperature initial repulsion resistance test A pressure-sensitive adhesive sheet (typically, a double-sided pressure-sensitive adhesive sheet) was cut into a size having a width of 10 mm and a length of 90 mm together with the release liner. Further, the surface of an aluminum plate having a width of 10 mm, a length of 90 mm, and a thickness of 0.5 mm was washed with toluene. Then, the first release liner was peeled off from the pressure-sensitive adhesive sheet, and the exposed pressure-sensitive adhesive surface was bonded to the surface of the aluminum plate to produce a test piece with the pressure-sensitive adhesive layer lined with the aluminum plate. After this test piece was allowed to stand at 5 ° C. for one day, as shown in FIG. 4A, the test piece 4 was placed on the outer periphery of a cylindrical screw tube 5 having a diameter of 40 mm with the aluminum plate 45 side inside. 4 was warped along the longitudinal direction for 10 seconds. Next, the second release liner 44 is peeled off from the pressure-sensitive adhesive layer 42 of the test piece 4, and as shown in FIG. 4B, the surface of the pre-cleaned gypsum board (adhered body) 46 is 5 ° C. Light pressure bonding was performed with a 500 g pressure roller. After the elapse of 5 seconds at the same temperature, as shown by phantom lines in FIG. 4B, the heights h1 and h2 at which both ends of the test piece 4 are lifted from the surface of the adherend 46 are measured, and the average value at both ends is obtained. It was calculated as the floating height (floating distance) of the test piece 4.
In this repulsion resistance test, three test pieces were used for each example (that is, n = 3), and the average value of the floating distances of these test pieces was recorded. Based on the measurement results, the low temperature initial repulsion resistance was evaluated according to the following criteria.
(Excellent): The floating distance was 5 mm or less.
○ (Good): The floating distance was greater than 5 mm and 15 mm or less.
X (Poor): The repulsion resistance was low, and the floating distance was larger than 15 mm.
In the case of carrying out the test with a single-sided pressure-sensitive adhesive sheet, the same operation as described above was performed on the object to be measured, with the back side of the pressure-sensitive adhesive sheet firmly fixed to an aluminum plate with a commercially available double-sided pressure-sensitive adhesive sheet. A certain pressure-sensitive adhesive surface may be lightly pressure-bonded to the adherend, and the low-temperature initial repulsion resistance may be measured.

(3) Shear performance evaluation test A 25 μm thick PET film (manufactured by Toray Industries, Inc., trade name “Lumirror S10”) is applied to the first adhesive surface (adhesive surface of the first adhesive layer) of the adhesive sheet (typically a double-sided adhesive sheet). ]) Was bonded together, and this was cut into a strip having a width of 10 mm to prepare a test piece. The second adhesive surface of the test piece (adhesive surface of the second pressure-sensitive adhesive layer) is exposed, and at room temperature (23 ° C.), a width of 10 mm is applied to a bakelite plate (phenol resin plate) as the adherend. A 2 kg roller was reciprocated once in a contact area of 20 mm in length, and the pressure was applied. After leaving the test piece attached to the adherend in this way for 30 minutes in the same environment, the adherend is suspended so that the length direction of the test piece is in the vertical direction, and the free end of the test piece is A load of 500 g was applied to the test piece, and allowed to stand in an environment of 40 ° C. for 2 hours in accordance with JIS Z0237. The distance (deviation distance) of the test piece after being left standing was measured.
In addition, when implementing a test using a single-sided adhesive sheet as a test piece, it is not necessary to bond a PET film to the first adhesive surface of the test piece.

<Example 1>
100 parts of a styrene isoprene block copolymer (manufactured by Zeon Corporation, product name “Quintac 3520”, styrene content 15%, diblock ratio 78%) as a base polymer, 10 parts of a terpene phenol resin Stir and mix 8 parts of terpene resin, 0.75 parts of isocyanate compound (product of Japan Polyurethane Industry Co., Ltd., product name “Coronate L”), 1 part of anti-aging agent and toluene as a solvent. Thus, a 50% NV pressure-sensitive adhesive composition was prepared.
Here, as the terpene phenol resin, the product name “YS Polystar S145” (softening point 145 ° C., hydroxyl value 100 mgKOH / g) manufactured by Yashara Chemical Co., Ltd. and the product name “YS Polystar T145” (softening point 145 ° C. Two types having a hydroxyl value of 60 mgKOH / g) were used at a weight ratio of 1: 1 so that the total amount was 10 parts. As the terpene resin, a product name “YS Resin PX1150N” (softening point 115 ° C., hydroxyl value of less than 1 mgKOH / g) manufactured by Yasuhara Chemical Co., Ltd. was used. As an anti-aging agent, a product name “IRGANOX CB612” manufactured by BASF (a blend composition of 2: 1 in a weight ratio of a product name “IRGAFOS 168” manufactured by BASF and a product name “IRGANOX 565” manufactured by the company) is used. used.

The pressure-sensitive adhesive composition obtained above was applied to the first surface of a PET film having a thickness of 12 μm as a substrate (trade name “Lumirror S10”, manufactured by Toray Industries, Inc.), dried at 120 ° C. for 3 minutes, A pressure-sensitive adhesive layer having a thickness of 64 μm was formed. A release liner subjected to a release treatment with a silicone release agent was bonded to the pressure-sensitive adhesive layer. Next, a pressure-sensitive adhesive layer having a thickness of 64 μm was formed on the second surface (surface opposite to the first surface) of the PET film, and a release liner was bonded thereto. Thus, the double-sided adhesive sheet which concerns on this example was produced.

<Examples 2 to 10>
A double-sided PSA sheet according to each example was prepared in the same manner as in Example 1 except that the type and amount of tackifying resin were changed to those shown in Table 1. In the table, “Neopolymer 150” is an aromatic petroleum resin (product name “Nisseki Neopolymer 150”, softening point 155 ° C., hydroxyl value of less than 1 mgKOH / g) manufactured by JX Nippon Oil & Energy.

<Example 11>
A double-sided pressure-sensitive adhesive sheet according to this example was prepared in the same manner as in Example 1 except that a non-woven fabric (trade name “SP-14K” manufactured by Daifuku Paper Co., Ltd.) was used instead of the PET film as the substrate.

<Examples 12 to 20>
A double-sided PSA sheet according to each example was prepared in the same manner as in Example 11 except that the type and amount of tackifying resin were changed to the contents shown in Table 2.

The low-temperature ball tack test, the low-temperature initial repulsion resistance test, and the shear performance evaluation test were performed on the double-sided PSA sheet according to each example. The results are shown in Tables 1 and 2.

In Tables 1 and 2, Example 1 in which the content of the tackifying resin is 10 to 60 parts by weight with respect to 100 parts by weight of the base polymer and 10 parts by weight or more of the tackifying resin having a softening point of 100 ° C. or higher is used. Each of the pressure-sensitive adhesive sheets according to 6 to 6 and Examples 11 to 16 exhibited a ball number of 4 or more in the low temperature ball tack test. In these examples, the deviation distance in the shear performance evaluation test was 0.2 mm or less, and good low-temperature initial repulsion resistance was exhibited. On the other hand, in Example 7 and Example 17 in which the amount of the tackifying resin used was less than 10 parts by weight, the floating distance in the low-temperature initial repulsion resistance test was about 30 mm. In Examples 8 to 10 and Examples 18 to 20 in which the use amount of the tackifying resin exceeded 60 parts by weight, the ball number in the low temperature ball tack test was 1 or less, and the low temperature initial repulsion resistance was low. Specifically, in the low-temperature initial repulsion resistance test, the floating distance of Example 8 and Example 18 in which the amount of tackifying resin used was 105 parts by weight was 20 mm, and the amount of tackifying resin used was 110 parts by weight. Example 9 and Example 19 had a lifting distance of 26 mm, and the amount of tackifying resin used was 140 parts by weight. Example 10 and Example 20 had a lifting distance of 30 mm, and the amount of tackifying resin was 60 parts by weight. It was recognized that the higher the amount was, the lower the initial low-temperature repulsion resistance was.
From these results, in the pressure-sensitive adhesive having a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound as the base polymer, the content of the tackifying resin is 10 to 60 parts by weight with respect to 100 parts by weight of the base polymer. the content of the tackifier resin T _H having a softening point of above 100 ° C. and 10 parts by weight or more, the ball tack under 0 ℃ environment is due to four or more of the adhesive sheet, while retaining excellent shear performance, It can be seen that the low-temperature repulsion resistance is improved.
Further, from the comparison between Examples 1 to 6 (Table 1) and Examples 11 to 16 (Table 2), even when the adhesive having the same composition is used, the one using the nonwoven fabric as the base material is more excellent. The tendency to show low temperature ball tack property and shear performance was confirmed. This is presumably because the adhesion with the adherend was improved by the nonwoven fabric being the base material.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

1, 2, 3 Adhesive sheet 11 First adhesive layer 12 Second adhesive layer 15 Base material 21, 22 Release liner

Claims (20)

1. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer containing a base polymer and a tackifying resin,
   The base polymer is a block copolymer of a monovinyl-substituted aromatic compound and a conjugated diene compound,
   The content of the tackifying resin is 10 to 60 parts by weight with respect to 100 parts by weight of the base polymer,
   The tackifying resin comprises a tackifier resin T _H having a softening point of above 100 ° C.,
   The content of the tackifier resin T _H is 10 parts by weight or more with respect to the 100 parts by weight of the base polymer,
   The pressure-sensitive adhesive layer is a pressure-sensitive adhesive sheet having a ball number 4 or more in a ball tack test under a 0 ° C. environment.
2. The tackifying resin includes a terpene phenol resin,
   The pressure-sensitive adhesive sheet according to claim 1, wherein the content of the terpene phenol resin is 10 parts by weight or more with respect to 100 parts by weight of the base polymer.
3. The pressure-sensitive adhesive sheet according to claim 2, wherein the content of the terpene phenol resin is 10 to 30 parts by weight with respect to 100 parts by weight of the base polymer.
4. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the base polymer is a styrene block copolymer.
5. The pressure-sensitive adhesive sheet according to claim 4, wherein the styrene block copolymer has a styrene content of 20% by weight or less.
6. The pressure-sensitive adhesive sheet according to claim 4 or 5, wherein a diblock ratio of the styrene block copolymer is 60% by weight or more.
7. The pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the base polymer contains at least one of a styrene isoprene block copolymer and a styrene butadiene block copolymer.
8. The tackifying resin includes at least one selected from the group consisting of petroleum resins, styrene resins, coumarone-indene resins, terpene resins, modified terpene resins, rosin resins, rosin derivative resins, and ketone trees. Item 8. The pressure-sensitive adhesive sheet according to any one of Items 1 to 7.
9. The tackifier resin T _H is terpene resins, terpene phenol resins, rosin phenolic resins, comprising at least one member selected from the group consisting of polymerized rosin and polymerized rosin ester, any one of claims 1 to 8 The pressure-sensitive adhesive sheet described in 1.
10. Wherein substantially all of the tackifying resin is a tackifier resin T _H, the pressure-sensitive adhesive sheet according to any one of claims 1-9.
11. The pressure-sensitive adhesive sheet according to any one of claims 1 to 10, wherein the tackifying resin _TH includes two or more terpene phenol resins.
12. The tackifier resin T _H has a softening point comprises a 120 ° C. or higher 200 ° C. or less of the terpene phenol resin, pressure-sensitive adhesive sheet according to any one of claims 1 to 11.
13. The tackifier resin T _H is a terpene phenol resin as a tackifier resin T _H1, than the adhesive imparting resin T _H1 and a lower tackifying resin T _H2 softening point, any of claims 1 to 12 one The pressure-sensitive adhesive sheet according to item.
14. The pressure-sensitive adhesive sheet according to claim 13, wherein the tackifying resin _TH2 contains a terpene resin.
15. The pressure-sensitive adhesive layer, as the tackifier resin _{T H,} a hydroxyl value comprises a tackifier resin _{T HO1} above 80 mg KOH / g, pressure-sensitive adhesive sheet according to any one of claims 1 to 14.
16. The pressure-sensitive adhesive layer, a tackifier resin _{T H,} further comprising a tackifier resin _{T HO2} having a hydroxyl value of 0 to less than 80 mg KOH / g, pressure-sensitive adhesive sheet according to claim 15.
17. The pressure-sensitive adhesive sheet according to any one of claims 1 to 16, wherein the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains an isocyanate compound.
18. The pressure-sensitive adhesive sheet according to any one of claims 1 to 17, wherein the pressure-sensitive adhesive layer has a thickness of 30 μm or more.
19. The pressure-sensitive adhesive according to any one of claims 1 to 18, further comprising: a base material; and a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer as the pressure-sensitive adhesive layers respectively supported on both surfaces of the base material. Sheet.
20. The pressure-sensitive adhesive sheet according to claim 19, wherein the substrate is a plastic film or a nonwoven fabric.

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