JP2012117013A - Adhesive composition and surface protection adhesive film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive, capable of peeling the end of the surface protection adhesive film easily from an adherend, even when a blanked piece is obtained by blanking from a laminate of the adherend and the surface protection adhesive film; and to provide a surface protection adhesive film.SOLUTION: This adhesive composition contains a copolymer (which may contain a coupling agent residue) containing a polymer block A mainly composed of an aromatic alkenyl compound unit and an aromatic alkenyl-conjugated diene copolymer block B containing conjugated diene units and aromatic alkenyl compound units at random, or its hydrogenated product, wherein, the aromatic alkenyl compound unit content rate (St(A+B)) in the whole polymer is 30-50 wt.%, and the weight ratio (A:B) of the total amount of the polymer block A to the total amount of the polymer block B is in the range of 5:95 to 25:75, and further at least either of an imine-based compound and fatty acid amide is contained.

Description

  The present invention relates to an adhesive composition and a surface protective adhesive film.

  Conventionally, it has been proposed to produce an optical component by punching a long sheet of an optical film in a state where a surface protection film is attached using a punching blade mold.

JP 2007-187781 A

In order to protect the surface of various members such as optical devices, metal plates, painted metal plates, resin plates, glass plates, etc. (hereinafter referred to as “adhered bodies”), it adheres to one side of a film-like substrate. A surface protective adhesive film (in general, sometimes referred to as a protective tape, a masking tape, or a surface protective sheet) in which an agent layer is laminated may be used. When the surface protective adhesive film is peeled off from the adherend, the surface protective adhesive film is peeled off from the adherend by grasping and pulling the end of the surface protective adhesive film.
When the above-mentioned punching is performed on the laminate in which the surface protective adhesive film is adhered on the adherend, the end of the laminated piece obtained by punching is pressed with a punching blade mold, The protective adhesive sheet and the member are firmly bonded. As a result, it may be difficult to remove the end from the adherend.
Some optical members have an uneven surface, such as a prism sheet or a diffusion film. In particular, when a surface protective adhesive sheet is attached to a member having such irregularities, the adhesive of the surface protective adhesive sheet enters the irregularities by punching, and it is particularly difficult to peel off the edges.
The problem of the present invention is that even if a punched piece obtained by punching a laminate of an adherend and a surface protective adhesive film is used, the surface protective adhesive film is covered by grasping and pulling the end of the surface protective adhesive film. An object of the present invention is to provide a surface protective adhesive film that can be easily peeled off from a body.

The pressure-sensitive adhesive composition of the present invention is
Polymer (ii): Including the following polymer block A and the following polymer block B, the general formula A-B-A (the symbols in the formula are as defined above) or the general formula (A-B) x A copolymer (II) having a structure represented by -Y (wherein x represents an integer of 1 or more, Y represents a coupling agent residue, and other symbols are as defined above), Containing its hydrogenated product,
Or
Polymer (i): comprising the following polymer block A and the following polymer block B, the general formula [AB] n (wherein A is the polymer block A, B is the polymer block B, n is A copolymer (I) having a structure represented by the formula (1) or a hydrogenated product thereof:
Containing the polymer (ii),
The overall aromatic alkenyl compound unit content (St (A + B)) of the polymer (i) and the polymer (ii) is 30 to 50% by weight,
The weight ratio (A: B) of the total amount of the polymer block A and the total amount of the polymer block B contained in each of the polymer (i) and the polymer (ii) is in the range of 5:95 to 25:75. And
further,
Contains at least one of an imine compound and a fatty acid amide.
Polymer block A:
Polymer block having a series of aromatic alkenyl compound units and mainly consisting of aromatic alkenyl compound units Polymer block B:
An aromatic alkenyl-conjugated diene copolymer block containing a conjugated diene unit and an aromatic alkenyl compound unit at random, wherein the aromatic alkenyl compound unit content (St (b)) is 10 to 35% by weight. Combined block

  According to the surface protective pressure-sensitive adhesive film of the present invention, even a punched piece obtained by punching a laminate of an adherend and a surface protective pressure-sensitive adhesive film is obtained by grasping and pulling the edge of the surface protective pressure-sensitive adhesive film. The protective adhesive film can be easily peeled off from the adherend.

It is a perspective view of the prism sheet to which the surface protection adhesive film of one mode of the present invention is applied. It is sectional drawing which shows the structure of the laminated body by which the surface protection adhesive film of one Embodiment of this invention was affixed on the prism sheet.

<Definition of symbols in this specification>
The symbol “˜” used to represent a numerical range in this specification is used with the intention that the numerical range includes the numerical values at both ends unless otherwise specified.
In the present specification, the “content” of the repeating unit of the polymer used in the term “aromatic alkenyl compound unit content” or the like means the weight ratio in terms of the monomer from which the repeating unit is derived, that is, the polymer. The ratio (wt%) of the weight of the monomer from which the repeating unit is derived to the weight of all monomers to be formed, that is, the alkenyl aromatic compound content of the polymer. Here, the “weight of all monomers for forming the polymer” approximates the weight of the polymer. Similarly, in the present specification, the “content ratio” of the repeating unit of the polymer block is the weight ratio converted to the monomer from which the repeating unit is derived, that is, the total monomer for forming the polymer block. It means the ratio (% by weight) of the weight of the monomer from which the repeating unit is derived to the weight. Here, the “weight of all monomers for forming the polymer block” approximates the weight of the polymer block.
In the present specification, the “vinyl bond content” means the total content of 1,2-vinyl bonds and 3,4-vinyl bonds calculated by the Morero method using an infrared absorption spectrum method.

<Adhesive composition>
The pressure-sensitive adhesive composition of the present invention contains the following polymer (ii). The pressure-sensitive adhesive composition may further contain the following polymer (i). In the present specification, the “polymer (i)” includes the following polymer block A and the following polymer block B, and is represented by the general formula [AB] n (wherein A represents the polymer block A and B represents The polymer block B is a copolymer (I) having a structure represented by n represents an integer of 1 to 3) or a hydrogenated product thereof.
In the present specification, the “polymer (ii)” includes the following polymer block A and the following polymer block B, and is represented by the general formula A-B-A (the symbols in the formula are as defined above) or General formula (AB) xY (wherein x represents an integer of 2 or more, Y represents a coupling agent residue, and other symbols are as defined above).
Or a hydrogenated product thereof.
In the present specification, a composition comprising the polymer (i) and the polymer (ii) may be simply referred to as a “copolymer composition”.

In the pressure-sensitive adhesive composition of the present invention, the total aromatic alkenyl compound unit content of the polymer (i) and the polymer (ii) is 30 to 50% by weight,
The weight ratio of the total amount of the polymer block A and the total amount of the polymer block B contained in the polymer (i) and the polymer (ii) is in the range of 5:95 to 25:75.

  In the present specification, the “polymer block A” is a polymer block in which aromatic alkenyl compound units are continuous and mainly composed of aromatic alkenyl compound units.

In the present specification, the “polymer block B” is an aromatic alkenyl-conjugated diene copolymer block in which a conjugated diene unit and an aromatic alkenyl compound unit are randomly included, and the aromatic alkenyl compound unit content (St (B)) is a polymer block of 10 to 35% by weight.
The pressure-sensitive adhesive composition contains at least one of an imine compound and a fatty acid amide. Thereby, sufficient adhesive force as a surface protective adhesive film can be obtained, and the end of the surface protective adhesive film can be easily peeled off from the adherend. That is, when the surface protective adhesive film is peeled off from the adherend, the end of the surface protective adhesive film can be easily peeled off from the adherend. It is not necessary to find an end that can be peeled off from the adherend, and can be peeled off immediately. Therefore, even if the surface protective adhesive film and the adherend are strongly pressed by punching, the end portion of the surface protective adhesive film adheres strongly to the adherend, so that the surface protective adhesive film is peeled off from the adherend. Occurrence of the phenomenon of becoming difficult can be suppressed.
The content of the imine compound is preferably 0.2 parts by weight or more with respect to 100 parts by weight of the total weight of the polymer (i) and the polymer (ii), and 1.5 parts by weight or less. Preferably there is.
Examples of the imine compound include polyethyleneimine and octadecyl isocyanate-modified polyethyleneimine. Examples of commercially available products include “Epomin 20” manufactured by Nippon Shokubai Co., Ltd.
The content of the fatty acid amide is preferably 0.15 parts by weight or more and 3.5 parts by weight or less with respect to 100 parts by weight of the total weight of the polymer (i) and the polymer (ii). It is preferable.
Examples of fatty acid amides include saturated fatty acid aliphatic bisamides such as ethylene bis stearamide, methylene bis stearamide, and hexamethylene bis stearamide; and m-xylylene bis stearamide, and NN′— Saturated fatty acid aromatic bisamides such as distearyl isophthalic acid amide are preferred. Among the saturated fatty acid aliphatic bisamides, ethylene bis stearamide is more preferable. Of the saturated fatty acid aromatic bisamides, m-xylylene bisstearic acid amide is more preferred. These saturated fatty acid bisamides may be used alone or in combination of two or more.
If the content of the imine compound and / or fatty acid amide is too small, the end portion of the surface protective adhesive film is difficult to peel off from the adherend. Moreover, when there is too much content of an imine type compound and / or fatty acid amide, the stability of the adhesive force to the adherend of the surface protective adhesive film may decrease, or some components contained in the adhesive It may adhere to the adherend and contaminate the adherend.

<Polymer block A>
As described above, the “polymer block A” is a polymer block in which aromatic alkenyl compound units are continuous and mainly composed of aromatic alkenyl compound units.

  The “aromatic alkenyl compound unit” is a repeating unit derived from an aromatic alkenyl compound. Examples of the “aromatic alkenyl compound” include styrene, tert-butylstyrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, 1,1-diphenylethylene, vinylnaphthalene, vinylanthracene, N , N-Jetyl-p-aminoethylstyrene, vinylpyridine and the like. Among them, the “aromatic alkenyl compound unit” is preferably a styrene unit because the raw materials are easily industrially available.

  The “polymer block A” needs to be composed of an aromatic alkenyl compound unit as a main repeating unit. Specifically, the aromatic alkenyl compound unit content is 80% by weight or more. By making the aromatic alkenyl compound unit content as high as 80% by weight or more, there is an advantage that the thermoplasticity of the pressure-sensitive adhesive composition can be improved and recycling of the pressure-sensitive adhesive composition becomes easier. The repeating unit other than the aromatic alkenyl compound unit that may be contained in an amount of less than 20% by weight includes a repeating unit derived from a compound copolymerizable with the aromatic alkenyl compound, such as a conjugated diene compound or (meth). Mention may be made of repeating units derived from acrylic ester compounds. Of these, 1,3-butadiene and isoprene are preferred because of their high copolymerizability with aromatic alkenyl compounds.

<Polymer block B>
As described above, the “polymer block B” is an aromatic alkenyl-conjugated diene copolymer block in which conjugated diene units and aromatic alkenyl compound units are randomly included, and the aromatic alkenyl compound unit content (St (B)) is a polymer block of 10 to 35% by weight.

  The “conjugated diene compound unit” constituting the “polymer block B” is a repeating unit derived from a conjugated diene compound. Examples of the “conjugated diene compound” include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-1,3-octadiene, 1,3- Examples include hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, myrcene, and chloroprene. Among them, the “conjugated diene compound unit” is at least one repeating unit selected from the group of 1,3-butadiene units and isoprene units because of high polymerization reactivity and easy availability of raw materials industrially. It is preferable.

  The “polymer block B” needs to be composed of a conjugated diene compound unit as a main repeating unit. From the viewpoint of exerting the effects of the present invention, the conjugated diene compound unit content is preferably in the range of 65 to 90% by weight.

Further, from the viewpoint of obtaining the effects of the present invention, the “polymer block B” needs to have an aromatic alkenyl compound unit content (St (b)) in the range of 10 to 35% by weight, and 13 to 33. It is preferably in the range of wt%, more preferably in the range of 16-30 wt%. When the aromatic alkenyl compound unit content is less than 10% by weight, the developability is heavy and the handling property may be deteriorated. On the other hand, when it exceeds 35 wt%, the flexibility of the pressure-sensitive adhesive composition is inferior, and sufficient adhesive force important for the surface protective pressure-sensitive adhesive film may not be ensured.
The “polymer block B” may also contain a repeating unit other than the conjugated diene compound unit and the aromatic alkenyl compound unit as long as the effects of the present invention are not hindered.

  The “polymer block B” preferably has a vinyl bond content in the range of 50 to 90% and more preferably in the range of 60 to 80% from the viewpoint of exerting the effects of the present invention. preferable. Moreover, there exists an advantage that the adhesive composition excellent in the balance of tack | tuck and adhesive force can be comprised by making a vinyl bond content rate into 50% or more.

<Copolymer (I)>
The “copolymer (I)” includes the following polymer block A and the following polymer block B, and is represented by the general formula [AB] n (wherein A is the polymer block A and B is the polymer block B). , N represents an integer of 1 to 3.).

  As “n” represents an integer of 1 to 3, as is clear, examples of the “structure represented by the formula [A-B] n” include AB, ABAB, And a structure represented by A-B-A-B-A-B. In these block copolymers, A and B may be the same or different in repetition.

  In the structure represented by [A-B] n, it is preferable that the terminal polymer block B occupies 2% by weight or more of the entire copolymer from the viewpoint of reliably exhibiting the effect of the polymer block B. Even when the terminal of some of the copolymers (I) has a structure of -A, the content of the terminal polymer block A is less than 2% by weight of the entire copolymer (I). Can exhibit the same effect as the terminal being the polymer block B. That is, the structure can be regarded as having a polymer block B at the end.

n needs to be an integer of 1 to 3. Industrial productivity becomes favorable by making n into this range. In addition, from the viewpoint of improving adhesive strength and material strength, n is more preferably 1 to 2, and particularly preferably 1. That is, as the “copolymer having a structure represented by the general formula [AB] n”, a block copolymer having a structure represented by the general formula AB is particularly preferable.

  The copolymer (I) or its hydrogenated product (polymer (i)) preferably has an aromatic alkenyl compound unit content in the range of 30 to 50% by weight, and is preferably 33 to 45% by weight. More preferred. By setting the aromatic alkenyl compound unit content in this range, it is possible to constitute a pressure-sensitive adhesive composition having an appropriate holding power and followability to the unevenness of the adherend surface, and having excellent spreadability. It becomes possible.

  The molecular weight of the polymer (i) is not particularly limited, but the weight average molecular weight is preferably 30,000 to 500,000, more preferably 80,000 to 300,000, and 100,000 to 200,000. Is particularly preferred. By setting the weight average molecular weight in the range of 30,000 to 500,000, the polymer (i), and thus the polymer (i) and the copolymer (II) or a hydrogenated product thereof (polymer (ii)) are formed. Industrial production of the copolymer composition can be facilitated. When the weight average molecular weight is less than 30,000, the polymer adheres to the production equipment or the like in the step of removing the solvent and drying the polymer, and industrial production of the polymer (i) may be difficult. On the other hand, when the weight average molecular weight is 500,000 or more, the solubility in a solvent and the heat melting property are deteriorated, and it may be difficult to process the pressure-sensitive adhesive body.

Since the hydrogenated copolymer (I) has excellent heat resistance and weather resistance, the double bond derived from the conjugated diene monomer is 80% or more, preferably 90% or more, more preferably 95%. As described above, a hydrogenated product in which an unsaturated bond is hydrogenated to a saturated bond by hydrogenation is preferable.
. In the present specification, the ratio of hydrogenation (hydrogenation rate) means a hydrogenation rate calculated from a 270 MHz, ¹ H-NMR spectrum using carbon tetrachloride as a solvent.
The polymer (i) may be a single type (one type) or a combination of two or more types.

<Copolymer (II)>
The “copolymer (II)” includes the following polymer block A and the following polymer block B, and is represented by the general formula ABA (the symbols in the formula are as defined above) or the general formula (A -B) x-Y (wherein x represents an integer of 2 or more, Y represents a coupling agent residue, and other symbols are as defined above).
It is a copolymer which has a structure represented by these.

As is apparent from the above general formula, the copolymer (II) has a polymer block A at all molecular terminals.
The terminal polymer block A preferably accounts for 2% by weight or more of the entire copolymer (II). This is to ensure that the effect of the polymer block A is exhibited. Even if the terminal of some of the copolymers (II) has a structure of -B, the content of the terminal polymer block B is less than 2% by weight of the entire copolymer (II). Can exhibit the same effect as that of the polymer block A at the end. That is, the structure can be regarded as having the polymer block A at the end.

  A structure represented by the general formula (AB) xY (wherein x represents an integer of 2 or more, Y represents a coupling agent residue, and other symbols are as defined above). In other words, the copolymer having has a structure in which the copolymer (I) is coupled by Y. Therefore, in the case of (AB) x-Y, since the mixture of (I) and (II) can be synthesized in the same reaction kettle, from an industrial point of view, (AB) xY Is preferred. When x is 3 or more, the copolymer is a so-called star polymer. x is preferably 2 to 4 from the viewpoint of suppressing side reactions during the production of the copolymer and controlling the physical properties of the copolymer.

  The copolymer (II) or its hydrogenated product (polymer (ii)) also has an aromatic alkenyl compound unit content in the range of 30 to 50 weights for the same reason as the polymer (i). Is preferable, and it is more preferable that it is 33 to 45 weight%.

  Since the polymer (ii) has excellent heat resistance and weather resistance, the double bond derived from the conjugated diene monomer is 80% or more, preferably 90% or more, more preferably 95% or more. It is preferable that the unsaturated bond is a hydrogenated product obtained by hydrogenating the saturated bond.

The molecular weight of the polymer (ii) is not particularly limited, but the weight average molecular weight is preferably 50,000 to 500,000, and more preferably 50,000 to 300,000. By making the weight average molecular weight in the range of 50,000 to 500,000, industrial production of the polymer (ii), and thus the copolymer composition comprising the polymer (i) and the polymer (ii) can be facilitated. Can be. When the weight average molecular weight is less than 30,000, the polymer adheres to the production equipment in the process of removing the solvent and drying the polymer, making it difficult to industrially produce the copolymer (II) or its hydrogenated product. There is a case. On the other hand, when the weight average molecular weight is 500,000 or more, the solubility in a solvent and the heat melting property are deteriorated, and it may be difficult to process the pressure-sensitive adhesive body.
The polymer (ii) may be a single type (one type) or a combination of two or more types.

<Copolymer composition>
As described above, the pressure-sensitive adhesive composition of the present invention contains the polymer (ii) as a constituent component or a copolymer composition comprising the polymer (i) and the polymer (ii) as a constituent component. Contained as. In this copolymer composition, the weight ratio of the polymer (i) and the polymer (ii) is preferably in the range of 90:10 to 0: 100. By including the polymer (i), it is possible to exert a preferable effect that it is possible to effectively prevent a problem (floating) in which the pressure-sensitive adhesive layer is lifted from the surface of the adherend and the film is peeled off. . On the other hand, by including 10 parts by weight or more of the polymer (ii) in 100 parts by weight of the total amount of the polymer (i) and the polymer (ii), the film is peeled off from the surface of the adherend. It is possible to exert a preferable effect that it is possible to effectively prevent a problem (glue residue) that the adhesive remains on the surface of the adherend and contaminates the surface of the adherend.
From the viewpoint of more reliably preventing the pressure-sensitive adhesive layer from being lifted and remaining glue, the weight ratio of the polymer (i) to the polymer (ii) is preferably in the range of 50:50 to 15:85.

  From the viewpoint of achieving the effect of the present invention, the weight ratio of the total amount of the polymer block A and the total amount of the polymer block B contained in the polymer (i) and the polymer (ii) is 5:95 to 25:75. It is necessary to be within the range. In addition, by containing 5 parts by weight or more of the polymer block A in 100 parts by weight of the total amount of the polymer block A and the polymer block B, it is possible to impart an appropriate holding force to the formed pressure-sensitive adhesive layer. The preferable effect of becoming can be exhibited. On the other hand, by including 75 parts by weight or more of the polymer block B in 100 parts by weight of the total amount of the polymer block A and the polymer block B, the pressure-sensitive adhesive layer to be formed is good against unevenness on the surface of the adherend. Therefore, it is possible to exert a preferable effect that the surface of the adherend can be surely protected. The weight ratio of the total amount of the polymer block A and the total amount of the polymer block B is preferably in the range of 5:95 to 25:75, and more preferably in the range of 7:93 to 23:77. A range of 10:90 to 21:79 is particularly preferable.

<Surface protective adhesive film>
The surface-protective pressure-sensitive adhesive film of the present invention has a base material layer and a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition of the present invention described above.
Preferably, the pressure-sensitive adhesive layer is laminated on one surface of the base material layer.

<Base material layer>
The base material layer is preferably a polyolefin base material layer.
Examples of the “polyolefin” include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, ethylene-α-olefin copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate copolymer. Examples thereof include a copolymer, an ethylene-methyl acrylate copolymer, an ethylene-n-butyl acrylate copolymer, and polypropylene (homopolymer, random copolymer, block copolymer).
These can be used alone or in combination of two or more. The “polyolefin” may be a polyolefin having a substituent, and a resin other than the polyolefin may be added. Furthermore, the end material of the polyolefin base material layer and the end material of the surface protection adhesive film which were produced in the manufacturing process of the surface protection adhesive film may be added.
The base material layer may be a single layer or a layer having two or more multilayer structures having different compositions.
The thickness of the base material layer can be appropriately adjusted depending on the use of the surface protective adhesive film. Usually, it is suitable to set the thickness to about 10 to 100 μm.

<Adhesive layer>
The said adhesive layer consists of an adhesive composition of this invention. In addition to the polymer (ii) or the polymer (ii) and the polymer (i), the pressure-sensitive adhesive composition includes a tackifier, a styrene block phase reinforcing agent, a softening agent, if necessary. Known additives such as antioxidants, light stabilizers, UV absorbers, fillers, pigments, adhesion promoters, olefin resins, silicone polymers, liquid acrylic copolymers, phosphate ester compounds, etc. are used as appropriate. You may contain.

  Examples of the tackifier used in the present invention include petroleum resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymers and alicyclic copolymers, Generally adhesives such as coumarone-indene resin, terpene resin, terpene-phenol resin, polymerized rosin resin such as rosin resin, (alkyl) phenol resin, xylene resin or hydrogenated products thereof What is used for can be used without a restriction | limiting in particular. It is more preferable to use a tackifier having a softening point of 90 to 140 ° C. These tackifiers may be used alone or in combination of two or more. In order to improve peelability and weather resistance, it is more preferable to use a hydrogenated tackifier. Moreover, you may use the tackifier marketed as a blend with an olefin resin.

The tackifier in the present invention means a compound that is compatible with a rubber layer that is a conjugated diene system or a hydrogenated soft segment thereof in an aromatic alkenyl block copolymer and can control the adhesive force. .
“Compatible” means that the tan δ peak temperature of a blend obtained by blending a tackifier with the copolymer composition is different from the tan δ peak temperature of the copolymer composition. That means. In the present specification, “tan δ peak temperature” means a temperature at which tan δ is maximized.

The styrenic block phase reinforcing agent is used to suppress the adhesion progress of the adhesive layer. The styrenic block phase reinforcing agent is an agent that reinforces the island phase of the sea-island structure formed by the aromatic alkenyl block copolymer, and has a property of being compatible with the domain made of the aromatic alkenyl block copolymer.
Examples of the styrenic block phase reinforcing agent used in the present invention include styrene and α-methylstyrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, tert-butylstyrene, and p-ethylstyrene as monomer units. And styrenic compounds such as divinylbenzene. These can be used alone or in combination of two or more. That is, the styrenic block phase reinforcing agent can be obtained by polymerizing these monomers. In the case of a copolymer composed of two or more types of monomers, it may be a block copolymer or a random copolymer. Among them, the styrenic block phase reinforcing agent preferably has a softening point of about 100 ° C. or higher, and more preferably 150 ° C. or higher. Specifically, trade names “ENDEX 155” (softening point 155 ° C.), “ENDEX 160” (softening point 160 ° C.) manufactured by Eastman Chemical Co., Ltd. are preferably used.
The amount of the styrenic block phase reinforcing agent used is preferably 40 parts by weight or less, more preferably 30 parts by weight or less, based on 100 parts by weight of the aromatic alkenyl block copolymer. The amount of the styrenic block phase reinforcing agent used is preferably 1 part by weight or more.

Softeners are usually effective in improving adhesive strength. Examples of the softener include low molecular weight diene polymer, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, paraffinic process oil, naphthenic process oil, aromatic process oil, castor oil, tall oil, natural oil, Those generally used for pressure-sensitive adhesives such as liquid polyisobutylene resin, polybutene, liquid rosin resin, or hydrogenated products thereof can be used without particular limitation. These softeners may be used alone or in combination of two or more.
As specific commercial products, trade names “Super Ester L”, “Super Ester A18”, Idemitsu Kosan Co., Ltd., trade name “Diana Process Oil”, etc., are preferably used.

The antioxidant is not particularly limited, and examples thereof include commonly used ones such as phenolic (monophenolic, bisphenolic, and polymeric phenolic), sulfur, and phosphorus.
Examples of the light stabilizer include hindered amine compounds.
The ultraviolet absorber is not particularly limited, and examples thereof include salicylic acid series, benzophenone series, benzotriazole series, and cyanoacrylate series.

Examples of the filler include calcium carbonate, magnesium carbonate, silica, zinc oxide, and titanium oxide.
Examples of the anti-adhesion progressing agent include soybean oil-modified alkyd resin (for example, trade name “Arachid 251” manufactured by Arakawa Chemical Industries, Ltd.), tall oil-modified alkyd resin (for example, product name “Arachid 6300” manufactured by Arakawa Chemical Industries, Ltd.). Etc.).
These additives may be used alone or in combination of two or more.

  Although the thickness in particular of an adhesive layer is not restrict | limited, For example, it is about 0.5-50 micrometers normally, Preferably it is 1-40 micrometers, More preferably, it is 2-30 micrometers.

Here, as the tackifier, those exemplified above can be used.
It is suitable that the tackifier is used in an amount capable of preventing adhesive residue when the surface protective adhesive film is peeled off from the adherend. For example, when used as a surface protective pressure-sensitive adhesive film for a prism sheet, the content of the tackifier in the pressure-sensitive adhesive composition is the rubber-based resin component [the polymer (ii) or the polymer (i) and The polymer (ii) (hereinafter, these may be collectively referred to as an aromatic alkenyl block copolymer)] is preferably 20 parts by weight or more, more preferably 20 to 50 parts per 100 parts by weight. Parts by weight, more preferably 25 to 40 parts by weight.
When the content of the pressure-sensitive adhesive imparting agent is 20 parts by weight or more, sufficient initial pressure-sensitive adhesive strength can be obtained for an optical film that has been subjected to antistatic treatment. Moreover, generation | occurrence | production of the adhesive residue is suppressed because content of an adhesive provision agent is 50 weight part or less.

The softening agent is preferably used in an amount that can suppress the adhesive residue when the surface protective adhesive film is peeled off from the adherend. For example, when used as a surface protective pressure-sensitive adhesive film for a prism sheet, the content of the softener in the pressure-sensitive adhesive composition is preferably 2 to 10 weights with respect to 100 parts by weight of the aromatic alkenyl block copolymer. Preferably it is 3-8 weight part.
When the content of the softening agent is 2 parts by weight or more, sufficient initial adhesive force can be obtained even for an optical film that has been subjected to antistatic treatment. By being 10 parts by weight or less, the deployment force is not increased, and the occurrence of adhesive residue is suppressed.
The surface protective adhesive film contains a tackifier and a softener in a specific ratio in addition to the polymer (ii) or the polymer (i) and the polymer (ii) in the adhesive layer. By doing so, it is possible to suppress the adhesive residue on the adherend with excellent developability while ensuring the initial adhesive force, particularly for the optical film that has been subjected to antistatic treatment.

<Sheet Laminate>
The above-mentioned surface protective adhesive film can be applied to a sheet laminate.
The sheet laminate includes a surface protective adhesive film and another sheet on which the surface protective adhesive film is attached. As the other sheet, an optical film such as a prism sheet is used. In the sheet laminate, other sheets to which the surface protective adhesive film is attached may have an antistatic treatment applied to the sheet surface.

  “Antistatic treatment has been applied” includes containing an antistatic agent. An antistatic agent is not specifically limited, A well-known thing can be used. For example, cationic surfactants such as acyloylamidopropyldimethylhydroxyethylammonium nitrate, acyloylamidopropyltrimethylammonium sulfate, cetylmorpholinium methosulfate, linear alkyl potassium phosphate, polyoxyethylene alkyl Nonionic surfactants such as potassium phosphate, anionic surfactant such as alkane sulfonate, N, N-bis (hydroxyethyl) -N-alkylamine, fatty acid ester derivatives thereof, polyhydric alcohol fatty acid partial esters An ionic surfactant or the like can be used. The blending ratio of these antistatic agents is appropriately determined according to desired characteristics. For example, when another sheet has a coating layer on its surface, that is, when the adhesive layer of the surface protective adhesive film is adhered to the coating layer, the antistatic agent per 100 parts by weight of the binder resin that is the main component of the coating layer The content of is usually about 0.1 to 10 parts by weight.

  In the sheet laminate, a plurality of surface protective adhesive films and other sheets may be alternately laminated. In particular, the sheet laminate may be a wound body wound with the surface protective adhesive film attached to another sheet.

  The lens portion of the prism sheet to which the surface protective adhesive film of the present invention is applied has a prism shape substantially consisting of a triangular prism. In the present specification, a surface having such a prism-shaped lens portion is referred to as a prism surface. More specifically, as shown in FIG. 1, the prism sheet 1 has a structure in which a plurality of triangular prism-shaped lens portions 3 are integrated on one surface of a flat sheet portion 2. The lens unit 3 has a substantially triangular prism shape. A plurality of lens portions 3 are closely arranged in parallel so that the ridge lines of the triangular prism are parallel to each other. The outer surface of the prism-shaped lens portion 3 is protected by the surface protective adhesive film of the present invention.

  For example, as shown in a cross-sectional view in FIG. 2, the first surface protective adhesive film 4 (surface protective adhesive film of the present invention) is attached to the portion of the prism sheet 1 where the lens portion 3 is provided. The first surface protective pressure-sensitive adhesive film 4 has a base material layer 5 and a pressure-sensitive adhesive layer 6 provided on one surface of the base material layer 5, and the plurality of prism sheets 1 from the pressure-sensitive adhesive layer 6 side. It is affixed to the side where the lens unit 3 is provided. Therefore, the surface protective adhesive film of the present invention is stuck so as to be in contact with the plurality of apexes 3 a of the triangular prism-shaped lens unit 3. Further, the cross-sectional shape of the lens portion 3 of this triangular prism is a triangle, but this triangle is preferably an isosceles triangle with the side fixed to the sheet as the base.

  On the other hand, a second surface protective adhesive film 7 is attached to the flat surface of the prism sheet 1 opposite to the side on which the lens portion 3 is provided, if desired.

  In addition, the side surface in the prism shape of a triangular prism shall mean the three side surfaces extended in the length direction of a triangular prism.

In a suitable prism sheet to which the surface protective adhesive film of the present invention is applied, it is preferable that the distance between adjacent prisms, that is, the pitch of the prisms, is approximately 10 to 1000 μm. More preferably, it is 10-500 micrometers, More preferably, it is 10-60 micrometers, The surface protection adhesive film of this invention is suitable with respect to the adherend which has a fine prism pitch.
Moreover, the sheet | seat laminated body may be shape | molded by punching. That is, by pressing a punching blade against the laminate from the surface protective adhesive film side or the other sheet side that is an adherend, the laminate is punched into a desired shape (for example, a long shape), and the desired shape and size are obtained. (For convenience, the laminated body after being punched is referred to as “laminated piece”). In the laminated piece thus obtained, the end portion of the surface protective adhesive film strongly adheres to the adherend. When the adherend is a sheet having irregularities such as a prism sheet, the pressure-sensitive adhesive layer of the surface protective adhesive film enters the irregularities, and the surface protective adhesive film and the adherend are more firmly bonded.
However, according to the surface protective pressure-sensitive adhesive film of this embodiment, the end portion of the surface protective pressure-sensitive adhesive film can be easily peeled off from the adherend without firmly adhering to the adherend. As a result, the operator can peel the entire surface protective adhesive film from the adherend by grasping and pulling the peeled end.

<Manufacturing method>
In the pressure-sensitive adhesive composition of the present invention, for example, copolymer (I) and copolymer (II) are synthesized by block polymerization, blended at a predetermined mass ratio, and then hydrogenated as desired. , Copolymer (I) or a hydrogenated product thereof, and a mixture of copolymer (I) or the hydrogenated product thereof, and an additive to be blended if desired is mixed by a conventional method .

  As the hydrogenation catalyst, a compound containing any one of Group Ib, IVb, Vb, VIb, VIIb, and Group VIII metals can be used. Examples thereof include compounds containing Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, and Pt atoms, and more specifically, Ti, Zr, Hf, Co, Ni, Rh. And metallocene compounds such as Ru, and supported heterogeneous catalysts in which metals such as pd, Ni, Pt, Rh and Ru are supported on a support such as carbon, silica, alumina, diatomaceous earth, and basic activated carbon. it can.

  Specific examples of the metallocene compounds include a Kaminsky catalyst having two ligands in which hydrogen on the cyclopentagenyl ring (Cp ring) or Cp ring is substituted with an alkyl group, and ansa. Examples thereof include a type metallocene catalyst, a non-crosslinked half metallocene catalyst, and a crosslinked half metallocene catalyst.

  Specific examples include JP-A-1-275605, JP-A-5-271326, JP-A-5-271325, JP-A-5-222115, JP-A-11-292924, and JP-A-11-292924. JP 2000-37632 A, JP 59-133203 A, JP 63-5401 A, JP 62-218403 A, JP 7-90017 A, JP 43-19960 A, Mention may be made of the catalysts described in JP-B 47-40473. These various catalysts may be used alone or in combination of two or more.

  Alternatively, when the copolymer (II) has a structure represented by the general formula (AB) xY (wherein the symbols are as defined above), the pressure-sensitive adhesive of the present invention. The composition may be produced by the following method (coupling method). In the coupling method, copolymer (I) or a hydrogenated product thereof (polymer (i)) and copolymer (II) or a hydrogenated product thereof (polymer (ii)) can be synthesized in one pot. Therefore, the production process is simple, the production cost is low, and the ratio of the polymer (i) to the polymer (ii) can be controlled by the kind and amount of the coupling agent.

The coupling method is
1st process: The process which synthesize | combines the copolymer which has a structure of [AB] by block polymerization,
Second step: A part of the copolymer having the structure of [AB] is converted into a coupling agent YZ _x (where “Y” is a coupling agent residue, “Z” is a leaving group, “X” represents an integer of 2 or more.), And a step of synthesizing a copolymer having a structure of {[AB] _x —Y}
When obtaining a hydrogenated product,
Third step: Hydrogenation of the copolymer having the structure [AB] and the copolymer having the structure {[AB] _x -Y}, respectively, by hydrogenation And a step of obtaining a copolymer composition comprising the combination (I) and the copolymer (II).

  Examples of the “coupling agent” include methyldichlorosilane, dimethyldichlorosilane, methyltrichlorosilane, butyltrichlorosilane, tetrachlorosilane, dibromoethane, tetrachlorotin, butyltrichlorotin, tetrachlorogermanium, bis (trichlorosilyl) ethane. Halogen compounds such as epoxidized soybean oil; carbonyl compounds such as diethyl adipate, dimethyl adipate, dimethyl terephthalic acid and diethyl terephthalic acid; polyvinyl compounds such as divinylbenzene; polyisocyanates; . Of these, methyldichlorosilane, dimethyldichlorosilane, methyltrichlorosilane, and tetrachlorosilane are preferred because they are easily industrially available and have high reactivity.

  The surface protective pressure-sensitive adhesive film of the present invention is, for example, a method of applying or spraying a liquid obtained by melting or dissolving the pressure-sensitive adhesive composition on a base sheet after producing a base sheet (base layer) by extrusion molding, Or it can manufacture by the method of sticking the base material sheet | seat and adhesive sheet which were obtained by the inflation method, or the method of coextruding a base material and the said adhesive composition using T die provided with the multilayer manifold. Especially, since the multilayer sheet | seat with which the base material layer and the adhesive layer contact | adhered is obtained, the method of manufacturing by coextrusion is preferable. A liquid obtained by melting or dissolving the pressure-sensitive adhesive composition of the present invention is also included in the pressure-sensitive adhesive composition of the present invention.

<Application>
The pressure-sensitive adhesive composition of the present invention is preferably applied to the pressure-sensitive adhesive layer of the surface protective pressure-sensitive adhesive film. Further, the surface protective adhesive film can be suitably used for uneven adherends such as an optical plate, a prism sheet, and a diffusion film, but is not limited thereto, and for example, has a smooth surface. It can also be used to protect the surface of the sheet.
Although it does not specifically limit as a material which comprises the sheet | seat used as a to-be-adhered body, Resin which has translucency, for example, acrylic resin, a polycarbonate, etc. are mentioned.

  Hereinafter, although the surface protection adhesive film of this invention is demonstrated in detail based on an Example, this invention is not limited to a following example.

(Synthesis of copolymer composition)
Polymer block A
A nitrogen-substituted reaction vessel is charged with 500 parts by mass of degassed / dehydrated cyclohexane, 20 parts by mass of styrene and 5 parts by mass of tetrahydrofuran, and 0.13 parts by mass of n-butyllithium is added at a polymerization start temperature of 40 ° C. Then, temperature rising polymerization was performed.
Polymer block B
After the polymerization conversion rate of the polymer A reached approximately 100%, the reaction solution was cooled to 15 ° C., and then 70 parts by mass of 1,3-butadiene and 10 parts by mass of styrene were added, followed by further temperature rising polymerization. .

  After the polymerization conversion rate reached almost 100%, 0.06 parts by mass of methyldichlorosilane was added as a coupling agent to carry out a coupling reaction. After the coupling reaction was completed, it was left for 10 minutes while supplying hydrogen gas at a pressure of 0.4 MPa-Gauge. A partially extracted polymer had a vinyl content of 64%, a weight average molecular weight of about 110,000, and a coupling rate of 60%.

Thereafter, 0.03 parts by mass of diethylaluminum chloride and 0.06 parts by mass of bis (cyclopentadienyl) titanium furfuryloxychloride were added to the reaction vessel and stirred. The hydrogenation reaction was started at a hydrogen gas supply pressure of 0.7 MPa-Gauge and a reaction temperature of 80 ° C., and when the hydrogen absorption was completed, the reaction solution was returned to room temperature and normal pressure, and the polymer was removed from the reaction vessel. A copolymer composition comprising (i) and polymer (ii) was obtained.
The properties of the copolymer composition are shown in Table 1.

Note that “St (A + B)”, “St (B)”, “St (A)”, and “St (b)” represent numerical values defined as follows. In the definition, “total polymer” means the whole of the polymer (i) and the polymer (ii).
“St (A + B)” is the aromatic alkenyl compound unit content of the whole polymer, and means a numerical value represented by the following formula. This is equal to the sum of the following “St (B)” and the following “St (A)”.
formula:
St (A + B) = (aromatic alkenyl compound unit weight in all polymers) / (total monomer unit weight in all polymers) × 100 (% by weight)
“St (B)” means a numerical value represented by the following equation.
formula:
St (B) = (aromatic alkenyl compound unit weight in all polymer blocks B) / (total monomer unit weight in all polymers) × 100 (% by weight)
“St (A)” means a numerical value represented by the following formula.
formula:
St (A) = (aromatic alkenyl compound unit weight in all polymer blocks A) / (total monomer unit weight in all polymers) × 100 (% by weight)
“St (b)” is the aromatic alkenyl compound unit content of the polymer block B, and means a numerical value represented by the following formula.
formula:
St (b) = (aromatic alkenyl compound unit weight in all polymer blocks B) / (total monomer unit weight in all polymer blocks B) × 100 (% by weight)
In Table 1, “A: B” represents a weight ratio between the total amount of the polymer block A and the total amount of the polymer block B.
In Table 1, “(i) :( ii)” represents the weight ratio of the polymer (i) to the polymer (ii).
Further, in Table 1, “conjugated diene content” represents the conjugated diene unit content of the polymer block B.
In Table 1, “Vinyl bond content” represents the vinyl bond content of the polymer block B.

(Examples 1-6, Comparative Examples 1-5)
To 100 parts by weight of the copolymer composition, 20 parts by weight of “Arcon P100” (manufactured by Arakawa Chemical Industries) as a tackifier and 20 parts by weight of “ENDEX 155” (Eastman Chemical) as a styrenic block phase reinforcing agent By adding polyethyleneimine (“Epomin RP20”, manufactured by Nippon Shokubai Co., Ltd.) and ethylenebisstearic acid amide (“Alflow HF50”, manufactured by NOF Corporation) in the amounts shown in Table 2. An agent composition was obtained.

  Polypropylene ("J715M", manufactured by Prime Polymer Co., Ltd.) is used as the base material, and the base material and each pressure-sensitive adhesive composition are coextruded by the T-die method, so that the base material layer with a thickness of 34 μm and the thickness of 6 μm are The surface protective adhesive films of Examples 1 to 6 and Comparative Examples 1 to 5 in which the adhesive layer was laminated and integrated were molded.

  A laminate was obtained by attaching a surface protective adhesive film to a prism sheet having irregularities (“BEF3”, manufactured by Sumitomo 3M).

(Evaluation)
The surface protective adhesive film was evaluated for “sticking” and “contamination”. The results are shown in Table 2.

<Criteria>
Sticking (easy to peel off the edge of the surface protection film when grasping the edge of the surface protection film and pulling it off the adherend)
A square laminate was obtained by punching the laminate from the surface protective adhesive film side with a square punching blade. Three laminated pieces were prepared, and the following test was performed on each laminated piece. Five attempts were made to grasp and peel the surface protective adhesive film from one side of the laminate using a thumb. In addition, the place where a surface protection film is grabbed was changed every time. It evaluated as follows by the number (successful number) of the laminated | multilayer piece which succeeded in peeling off the surface protection adhesive film 5 times among the three laminated pieces prepared.
◎ (Excellent): Successful number 3
○ (Good): Successful number 2
X (defect): Successful number 1 or zero contamination (adhesion of some components of the adhesive to the adherend (adhesive residue))
Three laminated pieces were prepared, and the following test was performed on each laminated piece. After the laminated piece was cured at 80 ° C. for 3 days, the surface protective film was peeled off. Subsequently, the uneven surface (prism surface) of the prism sheet illuminated with the backlight was visually observed to evaluate the presence or absence of adhesive residue.

◎ (excellent): No adhesive residue was observed on the surface of all three laminated pieces. ○ (good): No adhesive residue was observed on the two laminated pieces, but no adhesive residue was observed on the surface of one laminated piece. X (defect): Adhesive residue was observed on the surface of any of the three laminated pieces.

  The pressure-sensitive adhesive composition of the present invention is suitably used for a pressure-sensitive adhesive layer of a surface protective pressure-sensitive adhesive film such as a prism sheet or a diffusion film. The surface protective adhesive film of the present invention is suitably used for surface protection of prism sheets, diffusion films and the like.

1 Prism sheet 2 Sheet part 3 Lens part (prism)
3a Top of lens part (prism apex angle)
4 First surface protective adhesive film 5 Base material layer 6 Adhesive layer 7 Second surface protective adhesive film

Claims (5)

Polymer (ii): Including the following polymer block A and the following polymer block B, the general formula A-B-A (the symbols in the formula are as defined above) or the general formula (A-B) x A copolymer (II) having a structure represented by -Y (wherein x represents an integer of 1 or more, Y represents a coupling agent residue, and other symbols are as defined above), Containing its hydrogenated product,
Or
Polymer (i): comprising the following polymer block A and the following polymer block B, the general formula [AB] n (wherein A is the polymer block A, B is the polymer block B, n is A copolymer (I) having a structure represented by the formula (1) or a hydrogenated product thereof:
Containing the polymer (ii),
The overall aromatic alkenyl compound unit content (St (A + B)) of the polymer (i) and the polymer (ii) is 30 to 50% by weight,
The weight ratio (A: B) of the total amount of the polymer block A and the total amount of the polymer block B contained in each of the polymer (i) and the polymer (ii) is in the range of 5:95 to 25:75. And
further,
A pressure-sensitive adhesive composition comprising at least one of an imine compound and a fatty acid amide.
Polymer block A:
Polymer block having a series of aromatic alkenyl compound units and mainly consisting of aromatic alkenyl compound units Polymer block B:
An aromatic alkenyl-conjugated diene copolymer block containing a conjugated diene unit and an aromatic alkenyl compound unit at random, wherein the aromatic alkenyl compound unit content (St (b)) is 10 to 35% by weight. Combined block The content of the imine compound is 0.2 to 1.5 parts by weight with respect to 100 parts by weight of the total weight of the polymer (i) and the polymer (ii).
The pressure-sensitive adhesive composition according to claim 1. The content of the fatty acid amide is 0.15 to 3.5 parts by weight,
The pressure-sensitive adhesive composition according to claim 1 or 2.   The surface protection adhesive film which has a base material layer and the adhesive layer which consists of an adhesive composition of any one of Claims 1-3. The substrate layer is a polyolefin substrate layer;
The pressure-sensitive adhesive composition further contains a tackifier and a styrenic block phase reinforcing agent,
The ratio of the weight of the aromatic alkenyl compound unit in the polymer (i), the polymer (ii) and the styrenic block phase reinforcing agent to the weight of the pressure-sensitive adhesive layer (aromatic alkenyl compound unit content) is 20 ~ 50% by weight,
The surface protective adhesive film according to claim 4.

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