TW201302959A - Adhesive composition and adhesive sheet for surface protection - Google Patents

Abstract

An adhesive composition comprising: a copolymer (i) that is a copolymer (I) having a structure expressed by the general formula [A-B]n (n is an integer of 1-3 inclusive), or a hydrogenation product thereof; and a copolymer (ii) that is a copolymer (II) having a structure expressed by the general formula A-B-A or the general formula (A-B)x-Y (In the formula, x is an integer of one or more, and Y is a coupling agent residue), or a hydrogenation product thereof. The vinyl bond content of the conjugated diene unit of the polymer block (B) is 70-85%, and the content of alkenyl aromatic compound units in all of the polymer blocks (B), on the basis of the total monomer mass of copolymers (i) and (ii), is 15-35 mass% (A: a block comprising primarily alkenyl aromatic compound units in which the alkenyl aromatic compound unit is continuous. B: a block randomly comprising conjugated diene units and alkenyl aromatic compound units.).

Description

Adhesive composition and surface protection adhesive sheet

The present invention relates to an adhesive composition and an adhesive sheet for surface protection.

In the past, in the storage or transportation of various products (parts) such as optical devices, metal plates, coated metal plates, resin plates, and glass plates, in order to prevent the surface from adhering to stains, dust, or damage, A surface protective film in which an adhesive layer is disposed on one main surface of a polyolefin-based substrate is often used. The purpose of such a surface protective film is to protect the surface and adhere to the surface of the above article.

The surface protective film must be free from accidental peeling (including partial peeling) during storage and transportation of the above-mentioned products. Therefore, the surface protective film must have a certain degree of adhesion. In particular, when a surface protective film is attached to a product (part) having a concave-convex surface, since a large contact area cannot be obtained, it is necessary to form an adhesive layer having a strong adhesive force. Examples of such a product (part) having a concave-convex surface include a ruthenium sheet and a diffusion film which are optical members for liquid crystal displays.

On the other hand, the surface protective film must be peeled off with a small force as the user desires to peel it off as described above. As a related problem, there is a case where the adhesion force due to external factors such as time and temperature rises (so-called adhesion). An example of a problem in which such a problem occurs is a case where a product to which a surface protective film is attached is exposed to a high temperature during transportation and storage. This problem is especially easy to produce in products (adhesive When the surface of the body is a concave-convex shape.

Further, the surface protective film is required not to contaminate the surface of the above-mentioned article, that is, a part of the adhesive layer does not remain on the surface of the above-mentioned article at the time of peeling. Especially when the above product is an optical film or an optical sheet, this necessity is high.

However, the surface protective film is usually formed into a long strip shape and wound into a roll shape to be in the form of a wound body. The surface protective film in the form of the wound body is wound up at the time of use. Further, it is also required that the force (expansion force) required for the roll-off of the surface protective film is small, that is, the spreadability is required to be excellent. Further, when the winding is not smoothly performed due to insufficient development, a so-called stop mark is generated in the adhesive layer, which may damage the appearance of the surface protective film and may be transferred to the product (adhered body). Hey.

In order to meet such a demand, Patent Document 1 proposes a surface protective film which comprises two specific embedding blocks having an aromatic alkenyl polymer block and an aromatic alkenyl-conjugated diene copolymer block. The segment copolymer or its hydride is used for the adhesive layer, and has an appropriate initial adhesion and excellent spreadability, and inhibits adhesion and adhesion layer residue (ie, a part of the adhesive layer remains on the surface of the adherend). The situation).

[Patent Document 1] International Publication No. 2010/029773

However, a surface protective film which is more inhibited and has a more excellent spreadability is required.

Accordingly, an object of the present invention is to provide an adhesive composition capable of producing a surface protective film having suppressed adhesion and a surface protective film having suppressed adhesion.

A further object of the present invention is to provide an adhesive composition capable of producing a surface protective film having excellent spreadability and a surface protective film having excellent spreadability.

The present inventors have found that by controlling the vinyl bond content of two kinds of block copolymers including a conjugated diene compound unit and an aromatic alkenyl compound unit within a specific range, it is possible to suppress the adhesion of the adhesive containing the same. Adhesion of the surface protective film obtained by the composition.

The present inventors have further found that by controlling the content of the aromatic alkenyl compound of the above two kinds of block copolymers within a specific range, the spreadability of the surface protective film obtained from the adhesive composition containing the same can be improved. .

The present invention provides the form of the invention described in the following.

An adhesive composition comprising a copolymer (i) and a copolymer (ii), a copolymer (i) comprising the following polymer block A and a polymer block B described below, and having a general formula [AB] Copolymer (I) of the structure shown by _n or a hydride thereof (wherein A represents a polymer block A, B represents a polymer block B, n represents an integer of 1 to 3), and a copolymer ( Ii): containing the following polymer block A and the following polymer block B, and having the general formula ABA (the symbol in the formula represents the same meaning as described above) or the general formula (AB) _x -Y (formula) Wherein, x represents an integer of 1 or more, Y represents a coupling agent residue, and other symbols represent the copolymer (II) having the structure shown in the above) or a hydride thereof, and a conjugated diene unit in the polymer block B The content of the vinyl bond is in the range of 70 to 85%, and the unit content of the aromatic alkenyl compound in the total polymer block B based on the total monomer mass of the copolymers (i) and (ii) (St (B) )) is in the range of 15 to 35% by mass; the polymer block A is: the aromatic alkenyl compound unit is continuous, and the polymer block polymer block B mainly composed of the aromatic alkenyl compound unit is : random Containing the conjugated diene unit and an aromatic alkenyl aromatic alkenyl compound Units - conjugated diene block copolymer.

2. The adhesive composition according to item 1, wherein the unit content (St(b)) of the aromatic alkenyl compound as a whole of the polymer block B is in the range of 10 to 40% by mass, and the copolymers (i) and (ii) The unit content (St(A+B)) of the entire aromatic alkenyl compound is in the range of 35 to 55% by mass, and the mass ratio of the total amount of the polymer block A to the total amount of the polymer block B ( A: B) is in the range of 5:95~30:70.

A surface protective film comprising a base material layer and an adhesive layer comprising the adhesive composition of the above item 1 or 2 disposed on one main surface of the base material layer.

The adhesive composition of the present invention can produce a surface protective film which is adhered and inhibited. Further, one aspect of the adhesive composition of the present invention is that a surface protective film having excellent spreadability can be produced.

The surface protective film of the present invention is inhibited from sticking to adhesion. Further, one aspect of the surface protective film of the present invention has excellent spreadability.

1. Definition of the mark in this manual

In the present specification, the symbol "~" used to indicate the numerical range means 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 means the mass ratio converted to the monomer derived from the repeating unit (that is, the mass of the monomer derived from the above repeating unit with respect to the total monomer mass used to form the above polymer) Ratio) (% by mass). Here, "the mass of the total monomer used to form the above polymer" approximates the mass of the above polymer.

Similarly, in the present specification, the "content" of the repeating unit of the polymer block means the mass ratio converted to the monomer derived from the repeating unit (that is, the mass of the monomer derived from the above repeating unit relative to the polymer used to form the above polymer The ratio of the total monomer mass of the block) (% by mass). Here, "the mass of the total monomer used to form the above polymer block" approximates the mass of the above polymer block.

Specifically, the term used in the present specification is "the copolymer (i) and (ii) the overall aromatic alkenyl compound unit content" (St (A + B)), "all of the polymer block A aromatic Unit content of alkenyl compound" (St (A)), "unit content of aromatic alkenyl compound in all polymer block B" (St (B)), and "aromatic alkenyl compound of polymer block B as a whole" The unit content (St(b)) represents the numerical value defined by the following formula. In addition, the term "all polymer block A" and "all polymer block B" used in the present specification means that all of the polymers in the polymers (i) and (ii) are embedded unless otherwise specified. Section A" and "all polymer blocks B" in polymers (i) and (ii). The unit content of such an aromatic alkenyl compound is determined by ¹ H-NMR (hydrogen nuclear magnetic resonance). Further, the unit content of such an aromatic alkenyl compound can also be determined by infrared spectroscopy, and a value substantially the same as that of ¹ H-NMR can be obtained.

The "vinyl bond content" in the present specification means the total content of 1,2-vinyl bond and 3,4-vinyl bond calculated by the Morello method by infrared absorption spectroscopy. Further, the vinyl bond content of the hydride indicates the vinyl bond content of the polymer corresponding to the hydrogenation thereof.

In the present specification, the "ethylene bond content of the conjugated diene unit" means the content of the vinyl bond derived from the portion of the conjugated diene compound (monomer).

2. Adhesive composition

The adhesive composition of the present invention contains copolymers (i) and (ii) which will be described later in detail. The copolymers (i) and (ii) respectively contain both of the polymer blocks A and B described later.

In the adhesive composition of the present invention, the above polymer (i) is obtained from the viewpoint of obtaining a surface protective film having a sufficient holding force (force against offset). And the lower limit of the mass ratio (A:B) of the total amount of the polymer block A contained in (ii) to the total amount of the polymer block B is preferably 5:95, more preferably 10:90. On the other hand, the upper limit of the ratio (A: B) is preferably from the viewpoint of obtaining a good followability to the unevenness of the surface of the adherend and a highly reliable surface protective film protected by the surface of the adherend. It is 30:70, more preferably 25:75. The ratio (A:B) is preferably in the range of 5:95 to 30:70, more preferably in the range of 10:90 to 25:75.

2.1. Polymer Block A

The polymer block A is a polymer block mainly composed of an aromatic alkenyl compound unit.

The "aromatic alkenyl compound unit" is a repeating unit derived from an aromatic alkenyl compound. Examples of the aromatic alkenyl compound include styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, p-ethylstyrene, divinylbenzene, and 1 , 1-stilbene, vinylnaphthalene, vinyl anthracene, N,N-diethyl-p-amino ethyl styrene and ethylene Vinylpyridine or the like. Among them, the reason why the raw material is easily obtained industrially is that the "aromatic alkenyl compound unit" is preferably a styrene unit.

The polymer block A must contain a repeating unit mainly composed of an aromatic alkenyl compound unit. Specifically, the aromatic alkenyl compound has a unit content of 80% by mass or more. By having such a higher unit content of the aromatic alkenyl compound, the thermoplasticity of the adhesive composition can be improved, and the reuse of the adhesive composition can be facilitated. Polymer block A can also be less than 20% by mass The range of repeating units other than the unit of the aromatic alkenyl compound is contained in the range. As such a repeating unit, for example, a repeating unit derived from a conjugated diene compound or a (meth) acrylate compound, that is, a compound which can be copolymerized with an aromatic alkenyl compound can be mentioned. Among them, 1,3-butadiene and isoprene are preferred because of their high copolymerizability with the aromatic alkenyl compound. Such a repeating unit may be one type or two or more types.

2.2. Polymer Block B

The polymer block B randomly contains a polymer block of a conjugated diene unit and an aromatic alkenyl compound unit.

Here, the term "randomly" is broadly interpreted as a state in which the chain distribution of the conjugated diene unit and the aromatic alkenyl compound unit is a fixed statistic obtained by simultaneously polymerizing a conjugated diene and an aromatic alkenyl compound. The state of the rules.

From the viewpoint of exerting the effects of the present invention, the polymer block B is preferably composed mainly of a conjugated diene unit and an aromatic alkenyl compound unit. Specifically, the content of the conjugated diene unit and the aromatic alkenyl compound unit in the polymer block B is preferably 65% by mass or more, and more preferably 80% by mass based on the mass of all the polymer blocks B. %the above.

The "conjugated diene compound unit" constituting "polymer block B" means 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, and 1,3-pentadiene. 2-methyl-1,3-octadiene, 1,3-hexadiene, 1,3-cyclohexadiene, 4,5-diethyl-1 , 3-octadiene (4,5-diethyl-1,3-octadiene), 3-butyl 3-butyl-1,3-octadiene, myrcene, chloroprene, etc., among which 1,3-butadiene or the like is preferred.

Examples of the "conjugated diene compound unit" include 1,4-butadiene, 1,2-butadiene, 1,2-isoprene, 1,4-isoprene, and 3. A repeating unit such as 4-isoprene, wherein a repeating unit such as 1,4-butadiene or 1,2-butadiene is preferred. Furthermore, it is also known to the practitioner that the terminology herein (example, 1,4-) means the reaction form of the polymerization reaction.

The content of the vinyl bond of the conjugated diene unit in the polymer block B is in the range of 70 to 85% by mass, more preferably in the range of 75 to 85% by mass. By the content of 70% by mass or more, a surface protective film in which adhesion is suppressed is obtained. On the other hand, the content is 85 mass% or less, and a surface protective film having a sufficient adhesive force is obtained.

The lower limit of the unit content (St(b)) of the aromatic alkenyl compound as a whole of the polymer block B is preferably 10% by mass, more preferably 20% by mass, from the viewpoint of obtaining a surface protective film having excellent expandability. The best is 30% by mass. On the other hand, from the viewpoint of obtaining a surface protective film having sufficient adhesion, the upper limit of the content (St(b)) is preferably 40% by mass. The content (St (b)) is preferably in the range of 10 to 40% by mass, more preferably in the range of 15 to 40% by mass, most preferably in the range of 20 to 40% by mass.

Further, the polymer block B may contain a repeating unit other than the unit of the conjugated diene compound and the unit of the aromatic alkenyl compound without departing from the effects of the present invention. Examples of such a repeating unit include propylene, 2-methyl-2-butene, 3-methyl-1-butene, and 2-methyl-1-butene. The content of such repeating units is usually relative to the total monomer number in the entire polymer block B. The bit mass is 10% by mass or less, preferably 5% by mass or less.

2.3. Copolymer composition

The adhesive composition of the present invention contains a copolymer composition composed of copolymers (i) and (ii) as described above. In the present specification, the "copolymer composition composed of the copolymers (i) and (ii)" is simply referred to as "copolymer composition". The copolymers (i) and (ii) are described in detail below.

The lower limit of the mass ratio of the copolymer (i) to the copolymer (ii) ((i): (ii)) is preferably 10:90 from the viewpoint of obtaining a surface protective film having sufficient adhesion. On the other hand, from the viewpoint of obtaining a surface protective film having excellent spreadability, the upper limit of the ratio ((i): (ii)) is preferably 70:30. The ratio ((i): (ii)) is preferably in the range of 10:90 to 70:30.

The unit content (St(B)) of the aromatic alkenyl compound in all the polymer blocks B is in the range of 15 to 35 mass% based on the total monomer mass of the copolymers (i) and (ii), preferably. It is in the range of 25 to 35 mass%. By the content (St (B)) being 15% by mass or more, a surface protective film having excellent developability is obtained. On the other hand, the content (St (B)) is 35 mass% or less, and a surface protective film having a sufficient adhesive force is obtained.

In the adhesive composition of the present invention, the unit content of the aromatic alkenyl compound in the above polymers (i) and (ii) is obtained from the viewpoint of obtaining a surface protective film having excellent spreadability and suppressed adhesion. The lower limit of (St (A + B)) is preferably 30% by mass, more preferably 35% by mass, most preferably 40% by mass. On the other hand, the concept of obtaining a surface protective film with sufficient adhesion The upper limit of the content (St (A + B)) is preferably 50% by mass. The content (St (A + B)) is preferably from 30 to 50% by mass, more preferably from 35 to 50% by mass, most preferably from 40 to 50% by mass.

In the mixture of the copolymer (i) and the copolymer (ii), the copolymer (i) and the copolymer (ii) are each a hydride. In the hydride, as a whole, the double bond (unsaturated bond) derived from the conjugated diene monomer is 80% or more, preferably 90% or more, more preferably 95% or more (for example, about 98). %) is hydrogenated to a saturated bond.

The molecular weight of the copolymer (i) and (ii) is not particularly limited, but the weight average molecular weight thereof is preferably from 30,000 to 500,000, more preferably from 80,000 to 300,000, and still more preferably from 100,000 to 25 Ten thousand, especially good for 100,000 to 200,000. If the weight average molecular weight is too small, there is a case where industrial productivity is deteriorated. On the other hand, if the weight average molecular weight is too large, workability may deteriorate.

2.3.1. Copolymer (i)

The copolymer (i) contains the polymer blocks A and B as described above, and is a copolymer represented by the formula: [AB] _n or a hydrogenated product thereof (wherein A represents a polymer block A, B) The polymer block B is represented, and n represents an integer of 1 to 3).

In the copolymer (i), when two or more polymer blocks A or B are present, two or more polymer blocks A or B may be the same or different, but are preferably the same.

In the general formula [AB] _n , n represents an integer of 1 to 3. Therefore, the structure represented by the general formula [AB] _n is AB, ABAB, or ABABAB. Since n is in this range, the industrial productivity of the block copolymer represented by the above formula or its hydride is improved. Further, n is preferably 1 or 2, and particularly preferably 1 from the viewpoint of an appropriate adhesion of the adhesive layer.

The lower limit of the unit content of the aromatic alkenyl compound of the copolymer (i) is preferably 30% by mass, more preferably 33% by mass, from the viewpoint of obtaining a surface protective film having a sufficient holding force (force against offset). . On the other hand, from the viewpoint of obtaining a surface protective film having good followability to the unevenness of the surface of the adherend and having high reliability by the surface protection of the adherend, the upper limit of the content is preferably 50% by mass, more Good is 45% by mass. The unit content of the aromatic alkenyl compound of the copolymer (i) is preferably in the range of 30 to 50% by mass, more preferably in the range of 33 to 45% by mass.

The molecular weight of the copolymer (i) is not particularly limited, but the weight average molecular weight thereof is preferably from 30,000 to 400,000, more preferably from 30,000 to 300,000, and still more preferably from 50,000 to 250,000. 50,000 to 200,000. If the weight average molecular weight is too small, there is a case where industrial productivity is deteriorated. On the other hand, if the weight average molecular weight is too large, workability may deteriorate.

The copolymer (i) in the adhesive composition of the present invention may be one type or a mixture of two or more types, and is preferably one type. Here, whether or not the polymer is one type is judged based on the technical common sense in the technical field to which the present invention pertains. In other words, for example, when the degree of polymerization or the molecular weight of the polymer is deviated by a certain amount of technical knowledge, only the copolymer (i) having a different degree of polymerization and molecular weight is the same type within a certain range of variation.

The copolymer (i) is preferably a hydride. In the hydride, from the conjugate The double bond (unsaturated bond) of the diene monomer is 80% or more, preferably 90% or more, more preferably 95% or more (for example, about 98%) is hydrogenated to a saturated bond.

2.3.2. Copolymer (ii)

The copolymer (ii) contains the polymer blocks A and B as described above, and has a copolymer of the formula: (AB) _x -Y or a hydrogenated product thereof (wherein X represents 2 or more) An integer, Y represents a coupling agent residue, and other symbols indicate the same meaning as above).

In the copolymer (ii), when two or more polymer blocks A or B are present, two or more polymer blocks A or B may be the same or different, but are preferably the same.

It is also known from the above formula that the copolymer (ii) has a polymer block A at all molecular terminals thereof.

From the viewpoint of realizing the effect of the polymer block A, the polymer block A at the end is preferably 2% by mass or more based on the entire copolymer (ii). Further, even if a part of the copolymer (ii) has a structure of -B, and the content of the polymer block B at the terminal is less than 2% by mass of the copolymer (ii) as a whole, it can also be a polymer with a terminal. The same effect of block A. That is, it is considered that the above structure is substantially the polymer block A at the end.

A copolymer having a structure represented by the formula (AB) _x -Y (wherein x represents an integer of 2 or more, Y represents a coupling agent residue, and other symbols represent the same meaning as described above), in other words, has a copolymer ( i) A structure that is coupled by Y. When x is 2, the copolymer is considered to be substantially a triblock polymer (ABA). When x is 3 or more, the copolymer is a so-called star polymer. From the viewpoint of suppressing the side reaction at the time of production of the copolymer and controlling the physical properties of the copolymer, x is preferably from 2 to 4.

The lower limit of the unit content of the aromatic alkenyl compound of the copolymer (ii) is preferably 30% by mass, more preferably 33% by mass, from the viewpoint of obtaining a surface protective film having a sufficient holding force (force against offset). . On the other hand, from the viewpoint of obtaining a surface protective film having good followability to the unevenness of the surface of the adherend and having high reliability by the surface protection of the adherend, the upper limit of the content is preferably 50% by mass. More preferably, it is 45 mass%. The unit content of the aromatic alkenyl compound of the copolymer (ii) is preferably in the range of 30 to 50% by mass, more preferably in the range of 33 to 45% by mass.

The molecular weight of the copolymer (ii) is not particularly limited, but the weight average molecular weight is preferably 50,000 to 500,000, more preferably 80,000 to 300,000, further preferably 100,000 to 250,000, and particularly preferably 10 10,000 ~ 200,000. If the weight average molecular weight is too small, there is a case where industrial productivity is deteriorated. On the other hand, if the weight average molecular weight is too large, workability may deteriorate.

The copolymer (ii) may be used singly or in combination of two or more.

The copolymer (ii) is preferably a hydride. In the hydride, the double bond (unsaturated bond) derived from the conjugated diene monomer is 80% or more, preferably 90% or more, more preferably 95% or more (for example, about 98%), and is hydrogenated to a saturated bond.

2.3.3. Method for producing copolymer composition

The copolymer composition is obtained, for example, by hydrogenating a mixture of the copolymers (I) and (II) described below as needed. As another method, the copolymer composition is also obtained, for example, by mixing the copolymers (i) and (ii) in a conventional manner. The copolymers (i) and (ii) are obtained by hydrogenating the copolymers (I) and (II), respectively, as needed. In the copolymer composition, the copolymers (i) and (ii) are preferably all hydrides.

The copolymer (I) contains the polymer blocks A' and B' described later, and has a structure represented by the formula: [A'-B'] _n (wherein A' represents the polymer block A' , B' represents the polymer block B', and n represents an integer of 1 to 3).

The copolymer (II) contains a polymer block A' and B' which will be described later, and has a structure represented by the formula: (A'-B') _{x -} Y (wherein x represents an integer of 2 or more, Y represents a coupling agent residue, and other symbols indicate the same meaning as described above, and the vinyl bond content of all the conjugated diene compound units of the polymer block B' is in the range of 70 to 85% by mass.

The polymer block A' is a polymer block mainly composed of an aromatic alkenyl compound unit.

The polymer block B' contains a polymer block having a block of a conjugated diene compound unit and an aromatic alkenyl compound unit.

The copolymers (I) and (II) can be produced by block polymerization, respectively.

Copolymer obtained by mixing the obtained copolymers (I) and (II) a mixture of (I) and (II).

As another method, a mixture of the copolymers (I) and (II) can also be obtained by the following method (even method). It is preferred that the coupling method has the following advantages: the copolymers (I) and (II) can be synthesized in a single container, so that the manufacturing steps are simple; the manufacturing cost can be reduced; and the type or amount of the coupling agent can be different. To control the ratio of the copolymers (I) and (II).

The even method includes the following steps: a first step: a step of synthesizing a copolymer having a structure of [A'-B'] by block polymerization, and a second step: by a coupling agent YZ _x (wherein, "Y" a coupler residue, "Z" represents a leaving group, and "x" represents an integer of 2 or more) and a part of the copolymer having the structure [A'-B'] is coupled to have {[A'-B' The step of the copolymer of _x -Y} structure.

The coupling agent residue represented by Y is defined by a coupling agent used in the production of the block copolymer represented by the above formula or a hydride thereof.

Examples of the coupling agent include methyl dichlorosilane, dimethyl dichloromethane, methyl trichlorodecane, butyl trichloromethane, tetrachlorodecane, dibromoethane, and tin tetrachloride. , halogen compounds such as butyltin trichloride, antimony tetrachloride, bis(trichlorosilyl)ethane; epoxy compounds such as epoxidized soybean oil; diethyl adipate, a carbonyl compound such as dimethyl diacid, dimethyl terephthalate or diethyl terephthalate; a polyvinyl compound such as divinylbenzene; a polyisocyanate. Among them, it is industrially easy to obtain and the reactivity is high, so methyl dichlorodecane, dimethyl dichlorodecane, methyl trichlorodecane, tetrachloroguanidine Alkane is preferred.

The hydrogenation system may be, for example, a method of supplying hydrogen gas in the presence of a hydrogenation catalyst.

As the hydrogenation catalyst, a compound containing any one of metals of Groups Ib, IVb, Vb, VIb, VIIb, and VIII of the periodic table can be used. For example, a compound containing atoms of Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, and Pt may be mentioned. Specifically, a metallocene compound containing Ti, Zr, Hf, Co, Ni, Rh, Ru, or the like; or a metal such as Pd, Ni, Pt, Rh, or Ru can be used for carbon, cerium oxide, or aluminum oxide. Carrier-type heterogeneous catalysts such as diatomaceous earth and alkaline activated carbon.

Specific examples of the metallocene-based compound include a Kaminsky catalyst having two ligands, an ansa (ansa) type metallocene catalyst, a non-crosslinked metallocene catalyst, and crosslinking. A semimetallocene catalyst or the like, and the ligand is formed by substituting an alkyl group for a cyclopentadienyl ring (Cp ring) or a hydrogen on a Cp ring. For example, Japanese Patent Application Laid-Open No. Hei 1-275605, Japanese Patent Laid-Open No. Hei 5-271326, Japanese Patent Application Laid-Open No. Hei No. 5-271325, No. 5-222115 Japanese Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Japanese Laid-Open Patent Publication No. Hei 7-90017, Japanese Patent Publication No. Sho 43-19960, and Japanese Patent Publication No. Sho 47-40473. These various catalysts may be used singly or in combination of two or more.

a double bond derived from a unit of a conjugated diene compound, usually 80% or more thereof, Preferably, 90% or more, more preferably 95% or more (for example, about 98%) is hydrogenated.

Here, the hydrogenation ratio (hydrogenation rate) is a hydrogenation ratio calculated from 270 MHz and ¹ H-NMR spectrum using carbon tetrachloride as a solvent.

2.4. Other ingredients

In addition to the above copolymers (i) and (ii), the adhesive composition may optionally contain a tackifier, a styrenic block phase-reinforcing agent, a softener, and an antioxidant. A light stabilizer, a UV absorber, a filler, a pigment, an anti-adhesion agent, an olefin resin, an anthrone polymer, a liquid acrylic copolymer, a phosphate compound, etc. are usually used in an adhesive composition. additive.

The tackifier can be used, for example, for the purpose of further suppressing the generation of the residue of the adhesive layer. The tackifier refers to a phase in which the rubber layer is dissolved as a soft segment and the adhesion can be controlled. In addition, "compatibility" means a state in which the tan δ peak temperature of the mixture obtained by adding a tackifier to the copolymer composition is a value different from the tan δ peak temperature of the copolymer composition. In addition, in this specification, "tan δ peak temperature" represents the maximum temperature of tan δ.

The tackifier is not particularly limited, and a petroleum resin such as an aliphatic copolymer, an aromatic copolymer, an aliphatic ‧ aromatic copolymer or an alicyclic copolymer can be used without particular limitation; Coumarone-indene resin; terpene resin; terpene-phenolic resin; rosin resin such as polymerized rosin; (alkyl) phenol resin; xylene resin; or such hydrides, etc. Agent. A tackifier having a softening point in the range of 90 to 140 ° C is preferred. Also, in order to improve the peelability and weather resistance It is preferred to use a hydride type tackifier. These tackifiers may be used alone or in combination of two or more. Further, a commercially available tackifier may be used, and the commercially available tackifier is a mixture containing the above-mentioned tackifier in combination with an olefin resin.

When the tackifier is used, the upper limit of the amount used is, for example, about 1 to 50 parts by mass, more preferably about 1 to 40 parts by mass, per 100 parts by mass of the copolymer composition.

The styrene block phase reinforcing agent is a formulation of an island phase of a sea-island structure formed by reinforcing an aromatic alkenyl block copolymer, and can be used, for example, for the purpose of further suppressing adhesion of the adhesive layer; further improving the surface The spreadability of the protective film; and further suppressing the generation of the residual adhesive layer residue when the surface protective film is peeled off from the adherend.

Examples of the styrene-based block phase reinforcing agent include monomer units such as styrene and α-methylstyrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, and t-butylstyrene. A styrene compound such as ethyl styrene or divinyl benzene. These may be used alone or in combination of two or more. That is, the styrene block phase reinforcing agent can be obtained by polymerizing the monomers. When it is composed of two or more kinds of monomers, it may be a block copolymer or a random copolymer. Among them, the styrene block phase reinforcing agent preferably has a softening point of about 100 ° C or more, more preferably 150 ° C or more. Specifically, it is preferable to use the trade name "ENDEX 155" (softening point 155 ° C) and "ENDEX 160" (softening point 160 ° C) manufactured by Eastman Chemical Co., Ltd., and the like.

When the styrene-based block phase reinforcing agent is used, the amount thereof is preferably, for example, about 1 to 40 parts by mass based on 100 parts by mass of the copolymer composition. It is about 1 to 30 parts by mass.

The softener can be used, for example, to further increase the adhesion of the adhesive layer. The softening agent is not particularly limited, and for example, a low molecular weight diene polymer, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, paraffin process oil, naphthenic acid can be used. (naphthene) is a processing oil, an aromatic processing oil, castor oil, tall oil, natural oil, liquid polyisobutylene resin, polybutene or the like, and the like, which is usually used for an adhesive.

The antioxidant is not particularly limited, and examples thereof include a phenol-based (monophenol-based, bisphenol-based, and polymeric phenol-based) antioxidant, a sulfur-based antioxidant, and a phosphorus-based antioxidant.

The light stabilizer is not particularly limited, and examples thereof include a hindered amine compound.

The ultraviolet absorber is not particularly limited, and examples thereof include a salicylic acid-based ultraviolet absorber, a diphenylketone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, and a cyanoacrylate-based ultraviolet absorber. Agents, etc.

Examples of the filler include calcium carbonate, magnesium carbonate, cerium oxide, zinc oxide, and titanium oxide.

Examples of the anti-adhesive agent include a fatty acid decylamine, a long-chain alkyl graft of polyethyleneimine, and a soybean oil-modified alkyd resin (for example, a product name "ARAKYD 251" manufactured by Arakawa Chemical Industries, Ltd. ", etc.), tall oil modified alkyd resin (for example, trade name "ARAKYD 6300" manufactured by Arakawa Chemical Industries Co., Ltd.), and the like.

These additives may be used singly or in combination of two or more.

2.5. Manufacturing method

The adhesive composition of the present invention is produced by mixing the copolymers (I) and (II) and additives as needed in a conventional manner.

3. Surface protection film

The surface protective film of the present invention comprises a base material layer and an adhesive layer composed of the above-described adhesive composition of the present invention disposed on one main surface of the base material layer.

3.1 substrate layer

The base material layer in the surface protective film of the present invention 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, and ethylene-acetic acid. A vinyl ester copolymer, an ethylene-methyl acrylate copolymer, an ethylene-n-butyl acrylate copolymer, and a polypropylene (a homopolymer, a random copolymer, a block copolymer) and the like. Further, the "polyolefin" may also be a polyolefin having a substituent. These may be used alone or in combination of two or more.

The base material layer may further contain a resin other than polyolefin. Further, the base material layer may be formed of a polyolefin, a resin other than the desired polyolefin, and a polyolefin base material layer and/or a surface protective film end material produced in the production process of the surface protective film.

The base material layer may be a single layer or a layer having a multilayer structure of two or more different compositions.

When the substrate layer has a layer formed of a polyolefin, a resin other than the desired polyolefin, and a polyolefin substrate layer and/or a surface protective film end material produced in the process of manufacturing the surface protective film, the layer is more Good is adjacent to the adhesive layer.

The thickness of the base material layer can be appropriately adjusted depending on the use of the surface protective film or the like. Generally, it is preferable to set the thickness to about 10 to 100 μm.

Therefore, even when the surface protective film of the present aspect is attached to the surface of the enamel sheet for laminating storage, the lens portion of the cymbal sheet can be hardly damaged, so that it can be favorably used for protecting the cymbal sheet. After the face.

In particular, when the surface roughness, the average waviness height, and the average waviness length of the back surface of the base material layer are within the above specific range, even if a plurality of sheets are attached with a surface protective film, even if there is a small amount When the foreign matter is stuck, the small foreign matter can enter the concave portion of the surface undulation, and it is considered that the stress concentrated on the lens portion can be lowered as compared with the case where the surface is smooth.

3.2. Adhesive layer

The above adhesive layer is formed of the adhesive composition of the present invention.

The thickness of the adhesive layer is not particularly limited. If the adhesive composition of the present invention is used, sufficient adhesion can be obtained even for a relatively thin adhesive layer, for example, usually about 0.5 to 20 μm, preferably 1 ~15 μm, more preferably 2~10 μm. The manufacturing cost can be reduced by making the adhesive layer thin, and adhesion can be suppressed.

3.3. Manufacturing method

The surface protective film of the present invention can be produced, for example, by a method in which a substrate sheet (base material layer) is produced by extrusion molding, and the above adhesive composition is formed. a method of coating or spraying a liquid obtained by melting or dissolving a substrate sheet; a method of bonding a substrate sheet obtained by an inflation method to an adhesive sheet; or using a multi-layer manifold The T-die mold coextrudes the substrate material with the above-mentioned adhesive composition. Among them, since a multilayer sheet in which a base material layer and an adhesive layer are adhered can be obtained, a method of production by co-extrusion is preferred. Further, a liquid obtained by melting or dissolving the adhesive composition of the present invention is also included in the adhesive composition of the present invention.

4. Application

The surface protective film of the present invention can be preferably used for surface protection of various articles (parts). Among them, it can be preferably used for an adherend having irregularities such as an optical plate and a diffusion film. However, the present invention is not limited thereto, and can be used, for example, for surface protection of a surface smooth sheet.

The material of the sheet to be adhered to the adherend is not particularly limited, and examples thereof include a resin having light transmissivity, such as an acrylic resin or polycarbonate.

[Examples]

Hereinafter, the surface protective film of the present invention will be described in detail based on examples, but the present invention is not limited to the following examples.

(Manufacture of copolymer composition) (Synthesis of Polymer Block A)

500 parts by mass of degassed dehydrated cyclohexane, 15 parts by mass of styrene and 5 parts by mass of tetrahydrofuran were added to a nitrogen-substituted reaction vessel, and 0.13 parts by mass of n-butyllithium was added at a polymerization initiation temperature of 40 ° C. (n-butyllithium), temperature polymerization is carried out.

(Synthesis of polymer block B)

After the polymerization conversion ratio of the polymer A was about 100%, the reaction liquid was cooled to 15 ° C, and then 55 parts by mass of 1,3-butadiene and 30 parts by mass of styrene were added, and the temperature polymerization was further carried out.

(Synthesis of copolymers (i) and (ii))

After the polymerization conversion ratio was about 100%, 0.06 parts by mass of methyldichlorodecane was added as a coupling agent to carry out a coupling reaction. After the completion of the coupling reaction, the hydrogen gas was supplied while being pressurized at a pressure of 0.4 MPa-Gauge for 10 minutes. A part of the extracted polymer has a vinyl bond content of 73% in a conjugated diene unit in the polymer block B, a weight average molecular weight of about 160,000, and a coupling ratio of 40%.

Thereafter, 0.03 parts by mass of diethylaluminium chloride and 0.06 parts by mass of bis(cyclopentadienyl)tifurum furfuryl chloride were added to the reaction vessel and stirred. The hydrogenation reaction is started at a hydrogen supply pressure of 0.7 MPa-Gauge and a reaction temperature of 80 ° C, and the reaction solution is returned to normal temperature and normal pressure at the end of the absorption of hydrogen, and then taken out from the reaction vessel, thereby obtaining the copolymer (i) and (ii) Composition of the copolymer composition (Synthesis Example 1 of Table 1).

Hereinafter, the same operation as the raw materials having different composition ratios was carried out to obtain a desired copolymer composition (Synthesis Examples 1 to 8 of Table 1). The properties of the copolymer compositions are shown in Table 1. In the table, "wt%" means mass%. The vinyl bond content of the conjugated diene unit in the polymer block B is simply referred to as "vinyl bond content".

(Examples 1 to 5, Comparative Examples 1 to 3)

In the substrate, polypropylene (manufactured by Prime Polymer Co., Ltd., J715M) was used, and the substrate and the respective copolymer compositions obtained by the above respective synthesis methods were co-extruded by a T-die method to thereby make a 34 μm thick layer. The surface protective film of Examples 1 to 5 and Comparative Examples 1 to 3 in which the base material layer and the 6 μm thick adhesive layer were integrated was formed, and a wound body wound around a paper core having an inner diameter of 3 inches was obtained. .

(evaluation test)

The following (1) to (4) items were evaluated for each of the surface protective films obtained in the above manner. The results of these are shown in Table 2.

(1) Film formation

The appearance of each surface protective film formed by co-extrusion of the film formed as described above was visually observed and evaluated. The symbol "○" in the table indicates that there is no problem in appearance.

(2) Initial adhesion

Each surface protective film was attached to an acrylic plate at a pressure of 5.9×10 ⁵ Pa and a speed of 30 mm/min using a tabletop laminator at room temperature of 23° C. and a relative humidity of 50%. The surface roughness is 0.10 μm or less, and the surface of the SUS (stainless steel) plate is polished so that the surface roughness is 0.30 to 0.80 μm. After standing for 30 minutes in this environment, the 180-degree peel adhesion of the films (25 mm width) was measured at a speed of 300 mm/min according to JIS Z0237, and this was used as the initial adhesion.

In this case, the surfaces of the acrylic plate and the SUS plate were visually observed, and it was confirmed that there was no residue of the adhesive layer on the surface of the acrylic plate.

(3) Time-dependent adhesion

Each surface protective film was attached to the above for use at a temperature of 23 ° C and a relative humidity of 50% using a table laminator at a pressure of 5.9 × 10 ⁵ Pa and a speed of 30 mm / min. 2) The surface of the acrylic plate and SUS plate evaluated for the initial adhesion. Thereafter, it was allowed to stand at 60 ° C or 80 ° C for 30 minutes, and then left at room temperature for 30 minutes, after which the film (25 mm width) was measured at a speed of 300 mm/min according to JIS Z0237. Degree of peeling adhesion.

In this case, the surfaces of the acrylic plate and the SUS plate were visually observed, and it was confirmed that there was no residue of the adhesive layer on the surface of the acrylic plate.

The peeling adhesive force measured in the above manner was used as the temporal adhesive force, and the change ratio from the initial adhesive force to the temporal adhesive force (adhesion ratio) was calculated by the following formula.

Ratio of change (adhesion ratio) = (time-dependent adhesion / initial adhesion)

<Judgement criteria>

Ratio of change (adhesion ratio)

◎ (excellent): less than 1.5

○ (good): 1.5 or more and 2 or less

× (bad): more than 2

(4) adhesion from the back

Each surface protective film of the examples and the comparative examples was bonded under the conditions of a pressure of 5.9×10 ⁵ Pa and a speed of 30 m/min using a table bonding machine, and left at room temperature and 80° C. for 60 minutes. .

Removed from room temperature to room temperature at 80 ° C, placed for 30 minutes, included in For placement at room temperature, a 180-degree peel strength of 25 mm width is measured at a speed of 15 m/min according to JIS Z0237.

(5) Termination mark evaluation

Each surface protective film of the examples and the comparative examples was attached under the conditions of a pressure of 5.9 × 10 ⁵ Pa and a speed of 30 m / min using a table bonding machine, and allowed to stand in an environment of 80 ° C for 60 minutes. This was taken out to room temperature, and after standing for 30 minutes, a 180-degree peel strength of 25 mm width was measured at a speed of 15 m/min in accordance with JIS Z0237, and the presence or absence of the termination mark was evaluated.

Thereafter, the peeled surface protective film was attached to a crucible formed of an acrylic resin having a thickness of 60 μm at a pressure of 5.9 × 10 ⁵ Pa and a speed of 30 m/min (the distance between the crucibles was 50 μm, The height was 25 μm), and it was allowed to stand in an environment of 60 ° C for 30 minutes. After peeling off the surface protective film, the presence or absence of the end mark transferred to the enamel sheet was visually evaluated. Further, in order to exemplify the termination mark, a photograph of the surface protective film of Comparative Example 2 was carried.

<Judgement criteria>

◎ (excellent): no end mark was observed on the film and was not transferred to the bracts

○ (good): the end mark was observed on the film but not transferred to the bracts

× (bad): a stop mark was observed on the film and transferred to the bracts

[Industrial availability]

The adhesive composition of the present invention is suitably used for an adhesive layer of a surface protective film such as a diffusion film. The surface protective film of the present invention is suitable for surface protection of a diffusion film or the like.

Fig. 1 is a photograph showing the termination mark (Comparative Example 2).

Claims (3)

An adhesive composition comprising a copolymer (i) and a copolymer (ii), the copolymer (i) comprising the following polymer block A and the following polymer block B, and having the general formula [AB ] _n-(wherein, A represents the polymer block A, B represents polymer block B, n represents an integer of 1 to 3) shown in copolymer (I), or a hydride of structure, copolymer (ii) based Containing the following polymer block A and the following polymer block B, and having the general formula ABA (the symbol in the formula is the same as defined above) or the general formula (AB) _x -Y (wherein x is represented by a copolymer (II) having a structure of 1 or more, Y represents a coupling agent residue, and other symbols represent the same meaning as defined above, or a hydride thereof, and a conjugated diene unit in the polymer block B has a vinyl bond content of 70 Within the range of ~85%, and based on the total monomer mass of the copolymers (i) and (ii), the unit content (St(B)) of the aromatic alkenyl compound in all the polymer blocks B is 15~ In the range of 35 mass%; polymer block A: the aromatic alkenyl compound unit is continuous, and the polymer block polymer block B composed mainly of aromatic alkenyl compound units: randomly contains a conjugate An aromatic alkenyl-conjugated diene copolymer block of a diene unit and an aromatic alkenyl compound unit. The adhesive composition of claim 1, wherein the unit content of the aromatic alkenyl compound (St(b)) of the polymer block B as a whole is In the range of 10 to 40% by mass, the unit content (St(A+B)) of the copolymer (i) and (ii) as a whole aromatic alkenyl compound is in the range of 35 to 55% by mass, and the polymer block A The mass ratio (A:B) of the total amount to the total amount of the polymer block B is in the range of 5:95 to 30:70. A surface protective film comprising an adhesive layer composed of a base material layer and an adhesive composition according to claim 1 or 2 disposed on one main surface of the base material layer.