KR101642996B1 - Ultraviolet curing adhesive composition - Google Patents

Abstract

The present invention relates to a resin composition comprising a (meth) acrylic polymer (component A), a carboxylic acid having a polymerizable unsaturated group (component B), a photopolymerization initiator (component C), a silane coupling agent (component D) E component), the component A contains 0.5 to 20 mmol of a (meth) acryloyl functional group per 100 g of the polymer in the side chain and has a glass transition temperature of -55 캜 to 0 캜, a weight average molecular weight of 200 to 100 , The component C is an acylphosphine oxide photopolymerization initiator, the component D is a silane compound having an epoxy-based functional group, and the components A, B, C, D and E are contained in a predetermined ratio Sensitive adhesive composition.

Description

ULTRAVIOLET CURING ADHESIVE COMPOSITION [0002]

The present invention relates to an ultraviolet curing pressure-sensitive adhesive composition which exhibits an adhesive force by ultraviolet irradiation.

2. Description of the Related Art In recent years, electronic image display devices (electronic displays) such as plasma displays and liquid crystal displays have become widespread. In the plasma display, it is necessary to bond an antireflection film for improving visibility to the display surface, and it is also necessary to bond a polarizing plate or another functional film to the surface or the inner surface of the display have. In use for adhering these functional films, the use of pressure-sensitive adhesives using a (meth) acrylic polymer has been rapidly increasing.

Conventionally, in the application for sticking a functional film, a pressure-sensitive adhesive made by dissolving a (meth) acrylic polymer in an organic solvent is used as a main agent, and a heat crosslinking agent is added to this subject before use and heated, Called thermosetting pressure-sensitive adhesives have been used (see Patent Documents 1 and 2). Such a thermosetting pressure-sensitive adhesive is obtained by applying a heat-crosslinking agent to a subject, coating it on the surface of a functional film or the like, volatilizing the solvent component contained in the subject by heating, curing it for several days at room temperature or under heating, The crosslinking agent causes a crosslinking reaction and a stable adhesion performance is exhibited.

For example, Patent Document 1 discloses an acrylic polymer (A) having an alkyl (meth) acrylate and an unsaturated carboxylic acid as a monomer unit and having a weight average molecular weight of 500,000 or more, an alkyl (meth) acrylate and an unsaturated carboxylic acid as a monomer unit (B) having a weight average molecular weight of 0.2 to 50,000, a silane coupling agent, and a heat crosslinking agent, which has a larger carboxylic acid equivalent than that of the acrylic polymer (A), and a pressure-sensitive adhesive composition for an optical member . Further, in Patent Document 1, the pressure-sensitive adhesive composition is prepared in a state containing a solvent, dried and crosslinked at 110 ° C for 5 minutes to form a pressure-sensitive adhesive layer, and then cured at a high temperature of 50 ° C for 24 hours, An example of obtaining an optical member is disclosed.

Patent Document 2 discloses an active energy ray-curable pressure-sensitive adhesive composition for an optical laminate containing an ethylenic unsaturated group-containing acrylic resin, a photopolymerization initiator, and a silane compound. Patent Document 2 discloses that the pressure-sensitive adhesive composition is preferably diluted with a solvent to have a concentration of 10 to 20 mass%, and a heat crosslinking agent is preferably used. An example of curing for 4 days at a high temperature of 40 캜 Lt; / RTI >

These thermosetting pressure-sensitive adhesives have advantages such as good adhesiveness, high durability, high coating accuracy, and the like, but the problem of curing (aging) as described above is a problem. That is, since the product can not be used immediately and requires a period and place for curing, the problem remains that the handling of the product becomes troublesome and the storage cost is included.

Therefore, there is proposed an ultraviolet curing type pressure-sensitive adhesive which does not require curing at a high temperature or for a long period of time by using a UV curing component having a polymerizable unsaturated group. For example, there has been proposed an acrylic copolymer having a predetermined weight average molecular weight, an ultraviolet curable resin composition containing two unsaturated double bonds in the molecule, a monomer having an alkylene glycol chain in the molecule, and a photopolymerization initiator 3).

The ultraviolet curable pressure sensitive adhesive composition comprising the reactive polymer (A), the (meth) acrylic ester monomer (B), the monofunctional monomer (C) copolymerizable with the double bond and the photopolymerization initiator (D) (See Patent Document 4).

In addition, the present inventors have also found that the reactive polymer contains a reactive polymer, a photopolymerization initiator, and a monomer having a polymerizable double bond, wherein the reactive polymer contains a repeating unit derived from a (meth) acrylic monomer in the main chain and a (meth) (Meth) acryl-based polymer having an ultraviolet-curable pressure-sensitive adhesive composition (see Patent Document 5).

Japanese Patent Application Laid-Open No. 2004-263165 Japanese Patent Application Laid-Open No. 2006-316231 Japanese Patent Application Laid-Open No. 2006-312664 Japanese Patent Laid-Open No. 2001-64593 Japanese Patent Application Laid-Open No. 2006-282805

In the ultraviolet curable pressure-sensitive adhesive composition described in Patent Documents 3 to 5, when the ultraviolet ray is irradiated, the photopolymerization initiator acts and the polymerization reaction of the polymerizable monomer and the reactive polymer progresses, whereby the adhesive force is developed. Therefore, there is an advantage that the adhesive force can be expressed almost simultaneously with ultraviolet irradiation without heating in the expression of the adhesive force. Further, since the pressure-sensitive adhesive contains no heat-crosslinking agent, it has excellent properties which are not found in the thermosetting pressure-sensitive adhesive which does not require a curing period in the production of a pressure-sensitive adhesive (no curing).

However, the ultraviolet ray-curable pressure-sensitive adhesive tends to have poor optical durability and re-peelability as compared with the thermosetting pressure-sensitive adhesive, and is not sufficiently satisfactory for coating applicability at high speed or ultraviolet ray curability under an air atmosphere. Particularly, the pressure-sensitive adhesive used for bonding the functional film to an electronic display has a further improvement in technology level, such as improvement in productivity (coating speed), improvement in coating accuracy, thinning of the pressure- It was requested, and there was still a problem to be solved.

Disclosure of the Invention The present invention has been made to solve the problems of the prior art as described above. It is an object of the present invention to provide a pressure-sensitive adhesive composition which is excellent in ultraviolet curing property under an air atmosphere and has excellent optical durability, re- Curing type pressure-sensitive adhesive composition having a performance comparable to that of a thermosetting pressure-sensitive adhesive in terms of coating speed (coating speed), coating ability (coating accuracy, thinning of pressure-sensitive adhesive layer, etc.).

DISCLOSURE OF THE INVENTION The present inventors have intensively studied in order to solve the problems of the prior art as described above. As a result, they have found that a crosslinkable (meth) acrylic polymer having a polymerizable (meth) acryloyl group introduced into a side chain, It has been found that the above problems can be solved by using a polymerizable carboxylic acid having an unsaturated group, an acylphosphine oxide-based photopolymerization initiator, and a silane coupling agent having an epoxy-based functional group at a predetermined composition ratio. Specifically, the following ultraviolet curable pressure-sensitive adhesive composition is provided by the present invention.

(B component), a photopolymerization initiator (component C), a silane coupling agent (component D), and a mixture of the above-mentioned A (meth) acrylic polymer (component A), a carboxylic acid having a polymerizable unsaturated group and its oligomer (E) component, and the component (A) contains a repeating unit derived from a (meth) acrylic monomer in the main chain, and a compound having a polymerizable unsaturated group other than the component (Meth) acryloyl group-containing functional group having a (meth) acryloyl group-containing functional group per 100 g of the polymer and 0.5 to 20 mmol of the (meth) acryloyl functional group per 100 g of the polymer and having a glass transition temperature (Tg) (Meth) acryl-based polymer having an average molecular weight (Mw) in the range of 200,000 to 1,000,000, the component C is an acylphosphine oxide-based photopolymerization initiator, the component D is a silane coupling agent having an epoxy- A castle Min and the total amount of the component B is 100 parts by mass, the component A is contained in an amount of 80 to 99.5 parts by mass, the component B is contained in an amount of 0.5 to 20 parts by mass, the component C is contained in an amount of 0.05 to 3 parts by mass, To 5 parts by mass, and the E component in an amount of from 0 to 20 parts by mass.

[2] The crosslinked (meth) acryl-based polymer according to [1], wherein the component A has an alkoxysilyl-based functional group containing an alkoxysilyl skeleton in the side chain and has 0.04 to 4 mmol of the alkoxysilyl-based functional group per 100 g of the polymer. Sensitive adhesive composition.

[3] In the case where the E component is a polyfunctional oligomer having two or more (meth) acryloyl group-containing functional groups per molecule and the total amount of the A component and the B component is 100 parts by mass, the E component is preferably 0.5 Sensitive adhesive composition according to the above [1] or [2].

[4] The ultraviolet curable pressure-sensitive adhesive composition according to the above [3], wherein the E component is a polyfunctional oligomer having an aliphatic polyester as a basic skeleton and a weight average molecular weight (Mw) in the range of 1,000 to 10,000.

[5] The ultraviolet curable pressure-sensitive adhesive composition according to the above [3], wherein the E component is a polyfunctional oligomer having a bisphenol as a basic skeleton and a weight average molecular weight (Mw) in a range of 400 to 2,000.

[6] The ultraviolet curable pressure-sensitive adhesive composition according to the above [1] or [2], which contains, as the ultraviolet absorber (component F), a benzophenone compound having a lambda _max in a wavelength range of 350 to 400 nm.

[7] The ultraviolet curable pressure-sensitive adhesive composition according to [1] or [2], wherein the component C is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

The ultraviolet curable pressure-sensitive adhesive composition of the present invention is excellent in ultraviolet curing property in an air atmosphere and does not require curing, and is excellent in optical durability, re-releasability, productivity (coating speed), coating ability (coating precision, And has a performance comparable to a thermosetting pressure-sensitive adhesive.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the ultraviolet curable pressure-sensitive adhesive composition of the present invention will be described in detail. It should be noted, however, that the present invention includes all embodiments having specific features of the invention and is not limited to the embodiments described below.

[1] Definitions include:

In the following description, the term " (meth) acrylic polymer " refers to a repeating unit derived from a (meth) acrylic monomer (hereinafter, simply referred to as "X unit" Quot;). ≪ / RTI >

When a polymer (including an oligomer) is referred to as a " main chain ", it is taken to mean a carbon chain having the largest number of carbon atoms in the polymer. On the other hand, the term "side chain" means a carbon chain branched from the main chain (carbon chain having the greatest number of carbon atoms) of the polymer and having a carbon number smaller than that of the main chain.

The "polymerizable unsaturated group" means a polymerizable double bond such as an unsaturated bond having a polymerizable group, such as a vinyl group, a polymerizable triple bond such as an acetylene group, or the like. As long as these unsaturated bonds are polymerizable, their structures are not particularly limited. For example, it may constitute a part of a cyclic structure, such as a cyclohexenyl group.

[2] Structure of the present invention:

The ultraviolet curable pressure-sensitive adhesive composition of the present invention comprises at least one (B component), a photopolymerization initiator (component C), and a silane coupling agent (D component) of a carboxylic acid having a polymerizable unsaturated group and an oligomer thereof And a compound (E component) having a polymerizable unsaturated group other than the A component and the B component as a constituent component. Each component will be described below.

[2-1] (Meth) acrylic polymer (component A):

The "(meth) acrylic polymer" is a polymer containing a repeating unit derived from a (meth) acrylic monomer in the main chain. The pressure-sensitive adhesive composition of the present invention uses a " crosslinkable (meth) acrylic polymer " having a reactive functional group capable of crosslinking to the side chain as the " (meth) acrylic polymer ".

[2-1A] Main chain:

The main chain of the " crosslinkable (meth) acrylic polymer " includes repeating units derived from a (meth) acrylic monomer.

In general, the term "(meth) acrylic monomer" means acrylic acid, methacrylic acid or a salt or ester thereof. Specific examples include (meth) acrylic acid salts such as acrylic acid and methacrylic acid, ammonium (meth) acrylate, sodium (meth) acrylate and potassium (meth) acrylate; Propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, (meth) acrylate such as lauryl (meth) acrylate and cyclohexyl (meth) acrylate; (Meth) acrylate such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl Acrylate esters and the like.

Among the above-mentioned (meth) acrylic monomers, the component A preferably contains a repeating unit derived from a (meth) acrylate ester, and the repeating unit derived from ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate It is more preferable to contain repeating units derived from ethyl acrylate or butyl acrylate, and it is particularly preferable to include repeating units derived from ethyl acrylate. By including these repeating units, it is possible to exert a good adhesive property.

The component A may be a homopolymer containing only one (meth) acrylic monomer unit as the main chain or a copolymer containing two or more (meth) acrylic monomer units. However, it is preferably a copolymer containing two or more (meth) acrylic monomer units because it is easy to precisely adjust the physical properties of the coating film (pressure-sensitive adhesive layer) when the pressure-sensitive adhesive is used. In this case, it is particularly preferable to include repeating units derived from ethyl acrylate and butyl acrylate.

Further, it is sufficient that the component A contains a (meth) acrylic monomer unit, and that all repeating units are not a (meth) acrylic monomer unit. That is, the monomer unit may include a monomer unit other than the (meth) acrylic monomer (sometimes referred to as "another monomer unit") unless the effect of the present invention is impaired.

The kind of the " monomer other than the (meth) acrylic monomer " is not particularly limited, and for example, a monomer having a polymerizable unsaturated bond can be used. Specific examples include (meth) acrylamides such as (meth) acrylamide; (Meth) acrylonitrile; and (meth) acrylonitrile; Aromatic vinyls such as styrene and? -Methylstyrene; Vinyl carboxylates such as vinyl acetate and vinyl propionate; unsaturated dicarboxylic acids such as maleic anhydride, itaconic acid and fumaric acid; And N-vinyl lactams such as N-vinyl pyrrolidone and N-vinyl caprolactam.

Among the monomers other than the " (meth) acrylic monomers, " component A preferably includes repeating units derived from (meth) acrylonitriles, particularly acrylonitrile. By including these repeating units, the cohesive force of the pressure-sensitive adhesive can be improved and the re-peeling property can be improved.

In the (meth) acrylic monomer unit as the component A, the content of the (meth) acrylic monomer unit is preferably 50% by mass or more when the total amount of the monomer units constituting the main chain of the (meth) acrylic polymer is 100% By mass, more preferably 60% by mass or more, and particularly preferably 70% by mass or more. Among them, it is preferable that all of the main chains are composed of (meth) acrylic monomer units. If the content of the (meth) acrylic monomer unit is less than 50% by mass, the adhesive property tends to deteriorate, which is not preferable.

(Meth) acryl-based monomer, a (meth) acryl-based polymer having a (meth) acrylate unit and an acrylonitrile unit is preferable. Among them, when the total amount of the monomer units constituting the main chain of the (meth) acrylic polymer is 100% by mass, the content of the (meth) acrylate unit is preferably 70 to 98.9% by mass, the acrylonitrile unit is preferably 1 to 20% (Meth) acrylic polymer containing 0.1 to 10 mass% of other monomer units is particularly preferable.

[2-1B] branched chain:

The side chain of the " crosslinkable (meth) acrylic polymer " has a crosslinkable reactive functional group. By having the reactive functional group capable of crosslinking in the side chain, the A component is crosslinked not only with the other polymerization components (for example, the B component and E component described later) but also with the A component by ultraviolet irradiation. Accordingly, it is possible to increase the concentration of the gel in the adhesive layer to be formed, and to form an adhesive layer having excellent adhesive performance and high strength and durability (in particular, moisture resistance to heat and humidity).

The "crosslinkable (meth) acrylic polymer" is a crosslinkable reactive functional group and has a (meth) acryloyl functional group having at least a (meth) acryloyl skeleton in its side chain. In other words, a (meth) acryl-based polymer to be a basic skeleton may be modified by introducing a (meth) acryloyl-based functional group by a chemical modification.

In the present specification, when it is referred to as a "functional group containing a (meth) acryloyl skeleton", a functional group containing an "acryloyl skeleton" represented by the following formula (1) or a "methacryloyl skeleton" represented by the following formula , And also includes substituted derivatives in which all or part of the hydrogen atoms constituting the acryloyl skeleton or methacryloyl skeleton are substituted with other atoms or functional groups. In the present specification, these functional groups are sometimes referred to as "(meth) acryloyl-based functional groups".

Representative examples include acryloyl group, methacryloyl group and the like. The acryloyl group is preferable in that it can impart excellent polymerizability (further ultraviolet ray curability), and the methacryloyl group is preferable because it is more safe than the acryloyl group.

The (meth) acryloyl group functional group is not necessarily a functional group having a structure in which an acryloyl group or a methacryloyl group can be directly bonded to a main chain, and the acryloyl group or the methacryloyl group may have any structure Or may be a functional group having a structure capable of being indirectly bonded to the main chain through a functional group (e.g., acryloyloxy group, etc.).

The content of the (meth) acryloyl functional group differs also depending on the structure of the main chain, the weight average molecular weight, the glass transition temperature, the adhesive property and the like. However, it is necessary to contain 0.5 to 20 mmol of (meth) acryloyl group-containing functional group per 100 g of the polymer, preferably 0.5 to 15 mmol, particularly preferably 0.5 to 10 mmol. For example, the crosslinking (meth) acryl-based polymer having a weight average molecular weight of 420,000 preferably has 2.1 to 84, more preferably 2.1 to 63, (meth) acryloyl functional groups per one molecule of the polymer , And it is particularly preferable that it has from 2.1 to 42.

When the content of the (meth) acryloyl group-containing functional group is less than 0.5 mmol / 100 g, the gel content can not be sufficiently increased and the strength of the pressure-sensitive adhesive layer may be insufficient. In this case, 1) the pressure-sensitive adhesive composition is crushed by the own weight of the film product when the film product coated with the pressure-sensitive adhesive composition is rolled up in roll form, and the pressure-sensitive adhesive composition is peeled off from the end or side edge of the roll, There is a concern that the problem of pushing out may arise. Further, 2) an embossing film having unevenness is often used as a protective film such as a film product coated with a pressure-sensitive adhesive composition in recent years, and there is a possibility that a stamp of embossed shape may be formed on the film product. In order to solve such a problem, the content is preferably 0.5 mmol / 100 g or more. However, when it exceeds 20 mmol / 100 g, there is a possibility that the moisture resistance of the pressure-sensitive adhesive is lowered.

The side chain of the " crosslinkable (meth) acrylic polymer " preferably has an alkoxysilyl functional group containing an alkoxysilyl skeleton represented by the following formula (3) in addition to the (meth) acryloyl functional group as a reactive functional group.

(In the formula, R represents an alkyl group which may be substituted.)

The polymer having an alkoxysilyl group-containing functional group in the side chain is excellent in durability, particularly in heat resistance and resistance to humidity and humidity when a glass material is used as an adherend. Specifically, it exhibits excellent adhesiveness even under high-temperature conditions or high-temperature and high-humidity conditions, and has a characteristic of being excellent in adhesive property. In addition, by carrying out these modifications, it is possible to obtain a pressure-sensitive adhesive composition which is less likely to deteriorate the adhesive property even under the heat-resistant and moisture-resistant heat-and-heat conditions even when the amount of the B component is small.

In the present specification, the term "alkoxysilyl skeleton" means a skeleton in which at least one alkoxy group is bonded to a silicon atom, as shown in the above formula (3). Accordingly, the "functional group containing an alkoxysilyl skeleton" includes a functional group in which a functional group other than any atom or alkoxy group is bonded to a silicon atom in addition to an alkoxy group. In the present specification, these functional groups are sometimes referred to as "alkoxysilyl-based functional groups".

Specific examples thereof include trialkoxysilyl group, dialkoxysilyl group, monoalkoxysilyl group and the like. Among them, a trialkoxysilyl group is particularly preferable because it can be introduced by using a trialkoxysilane derivative which is relatively easy to obtain.

In addition, the alkoxysilyl-based functional group is not necessarily a functional group having a structure in which the alkoxysilyl skeleton can be directly bonded to the main chain, and may be a functional group having a structure in which the alkoxysilyl skeleton can be indirectly bonded through any atom or a functional group ( For example, a trialkoxysilylalkyl group and the like).

The preferred content of the alkoxysilyl-based functional group is also different depending on the structure of the main chain, the weight average molecular weight, the glass transition temperature, and the like. However, the alkoxysilyl-based functional group is preferably contained in an amount of 0.04 to 4 mmol, more preferably 0.04 to 2 mmol, and particularly preferably 0.04 to 1 mmol per 100 g of the polymer. For example, the crosslinkable (meth) acryl-based polymer having a weight average molecular weight of 420,000 preferably has from 0.17 to 17 alkoxysilyl-based functional groups per molecule, more preferably from 0.17 to 8.5, more preferably 0.17 To 4.2.

When the content of the alkoxysilyl-based functional group is less than 0.04 mmol / 100 g, the effect of modifying with an alkoxysilyl-based functional group (specifically, durability when a glass material is used as an adherend, particularly excellent heat resistance, May not be obtained sufficiently. On the other hand, if it exceeds 4 mmol / 100 g, the viscosity of the polymer tends to increase with time depending on the polymer composition and the like.

The method for producing the crosslinkable (meth) acrylic polymer is not particularly limited. For example, a method in which a (meth) acryloyl functional group and an alkoxysilyl functional group are introduced into a (meth) acrylic polymer as a basic skeleton Method (chemical modification method).

As a specific example of the chemical modification method, for example, a (meth) acrylic polymer having a hydroxyl group is used as a base polymer, and an alkoxysilane compound having an isocyanate group and having a (meth) acrylic compound or an isocyanate group is directly added to the hydroxyl group of the base polymer (Meth) acryloyl group-containing functional group and an alkoxysilyl group-containing functional group by direct bonding (direct bonding method).

The "(meth) acrylic polymer having a hydroxyl group" can be obtained by copolymerizing a hydroxyl group-containing (meth) acrylate ester such as 2-hydroxyethyl acrylate with another (meth) acrylic monomer. Examples of the (meth) acrylic compound having an isocyanate group include 2-methacryloyloxyethyl isocyanate (trade name: CALENS MOI, manufactured by Showa Denko K.K.) and 2-acryloyloxyethyl isocyanate (Manufactured by Showa Denko K.K.) and 2- (2-methacryloyloxyethyloxy) ethyl isocyanate (trade name: CALENS MOIEG, manufactured by Showa Denko K.K.). On the other hand, examples of the alkoxysilane compound having an isocyanate group include 3-isocyanate propyltriethoxysilane (trade name: KBE-9007, manufactured by Shin-Etsu Chemical Co., Ltd.).

As the chemical modification method, a polyfunctional compound such as a polyisocyanate compound is bonded to the hydroxyl group of the base polymer, and a (meth) acrylic compound or a hydroxyl group-containing alkoxysilane compound having a hydroxyl group is indirectly bonded (Meth) acryloyl group-containing functional group and an alkoxysilyl-based functional group may be introduced (indirect coupling method).

Examples of the " polyisocyanate compound " include methylenediphenyl diisocyanate (MDI), tolylene diisocyanate (TDI), and isophorone diisocyanate (IPDI). Examples of the "(meth) acrylic compound having a hydroxyl group" include the aforementioned (meth) acrylate containing a hydroxyl group. Examples of the " alkoxysilane compound having a hydroxyl group " include 3-hydroxypropyltriethoxysilane and the like.

The production method of the base polymer is not particularly limited, and conventionally known methods such as solution polymerization, suspension polymerization and bulk polymerization can be used. For example, in the case of using solution polymerization, an ethylenically unsaturated monomer mixture comprising a (meth) acrylate monomer component and, if necessary, an ethylenically unsaturated monomer component copolymerizable therewith may be dissolved in an appropriate solvent such as an organic solvent, Followed by heating and stirring in a stream of nitrogen.

As the base polymer, a commercially available acrylic copolymer may also be used. (Solid content: 30%, Mw: 65 (trade name): Parcolon AW4500H (solid content: 40%, Mw: 32,000, Tg: -8 캜, toluene solvent, manufactured by Negami Kogyo Co.) , Tg: -36 占 폚, toluene solvent, manufactured by Negami Kogyo Co., Ltd.).

As the method for producing the crosslinkable (meth) acrylic polymer, the alkoxysilyl-based functional group is inserted into the skeleton of the base polymer by copolymerizing a monomer having an alkoxysilyl-based functional group with another monomer. As the (meth) acrylo- And introducing the alkoxysilyl functional group into the base polymer into which the alkoxysilyl-based functional group is inserted by chemical modification (polymerization method).

More specifically, the polymerization method is a method in which a monomer mixture comprising a (meth) acrylic monomer, a monomer having a hydroxyl group and a monomer having an alkoxysilyl functional group is subjected to a polymerization reaction to obtain a first monomer having an alkoxysilyl functional group and a hydroxyl group (Meth) acryl-based polymer is introduced into the hydroxyl group of the base polymer by a chemical modification to introduce a (meth) acryloyl-based functional group into the hydroxyl group of the base polymer to obtain a second crosslinked (meth) acrylic polymer, ) Is a method of obtaining an acrylic polymer.

Examples of the " monomer having an alkoxysilyl functional group " include methacryloyloxytrialkoxysilane, acryloyloxytrialkoxysilane, and vinyltrialkoxysilane. Of these, methacryloyloxytrialkoxysilane or acryloyloxytrialkoxysilane is preferably used in view of high reactivity at the time of polymerization, and acryloyloxytrialkoxysilane is particularly preferably used.

[2-1C] Average molecular weight:

Component A has a weight average molecular weight (Mw) in the range of 200,000 to 1,000,000. If the weight average molecular weight is less than 200,000, it is not preferable that the adhesive is used because adhesive residue on the adherend increases and the adherend tends to be contaminated. On the other hand, when the number average molecular weight exceeds 1,000,000, miscibility with solvents and monomers becomes poor, adhesion loss during the preparation of the composition increases, and problems such as deterioration of the handling of the coating liquid and deterioration of coating property may occur have. More specifically, there are cases where a coating film is formed on a film to be coated or the coating liquid is stretched like a thread. The reason why the coating liquid is stretched like a thread is not preferable because the viscosity of the coating liquid is raised by the rotation of the coating roll.

In order to obtain the above effect more reliably, the weight average molecular weight is more preferably in the range of from 250,000 to 800,000, and particularly preferably in the range of from 400,000 to 600,000.

The weight average molecular weight can be appropriately selected depending on polymerization conditions for polymerizing the (meth) acrylic polymer to be the main chain, for example, the kind and amount of the polymerization initiator, the kind and amount of the chain transfer agent, Can be controlled within the above-mentioned range by suitably controlling. In addition, among commercially available (meth) acrylic polymers, those having a desired weight average molecular weight may be suitably selected and modified.

In the present specification, "weight average molecular weight" means the weight average molecular weight in terms of polystyrene measured by the GPC method (Gel Permeation Chromatography Method).

Specifically, it is preferable to dissolve each sample in tetrahydrofuran (THF) so that the solid content thereof becomes 0.025%, and measure the solution under the following conditions. (1) GPC measuring device; A high-speed GPC apparatus HLC-8820 (trade name, manufactured by Tosoh Corporation), (2) a column; TSK-GEL series (trade name, manufactured by TOSOH CORPORATION), (3) Mobil; THF, (4) flow rate; 1 ml / min, (5) column temperature; 40 DEG C, (6) detector; RI, UV, (7) conversion; polystyrene.

[2-1D] Glass transition temperature (Tg):

Component A has a glass transition temperature (Tg) in the range of -55 to 0 占 폚. When the glass transition temperature is within this range, appropriate adhesive performance is exhibited when the pressure-sensitive adhesive is used. When the glass transition temperature is higher than 0 ° C, it is not preferable because the pressure-sensitive adhesive tends to lower the tack strength or decrease the compatibility with the solvent. On the other hand, if it is less than -55 占 폚, it is not preferable because when the pressure-sensitive adhesive is used as the pressure-sensitive adhesive, the amount of the residual paste on the adherend increases and the adherend tends to be contaminated. In order to obtain these effects more reliably, the glass transition temperature is preferably within a range of -40 to -10 占 폚, and more preferably within a range of -30 to -20 占 폚.

The glass transition temperature can be adjusted within the above range by suitably controlling the type and ratio of the repeating units constituting the (meth) acrylic polymer as the main chain. The glass transition temperature (theoretical value) of the polymer P composed of the repeating units derived from the monomers M ₁ , M ₂ , ..., M _n can be calculated from the Fox's equation (the following formula (1) The type and proportion of repeat units can be adjusted with reference to the formula.

[Equation 1]

1 / TgP = r ₁ / TgM ₁ + r ₂ / TgM _{2 - -} + r _n / TgM _n

(Glass transition temperature (K) of polymer P, TgM ₁ : glass transition temperature (K) of homopolymer of monomer M ₁ , TgM ₂ : glass transition temperature (K) of homopolymer of monomer M ₂ , TgM _n is the glass transition temperature (K) of the homopolymer of the monomer M _n , r ₁ is the mass fraction of the monomer M ₁ unit in the polymer P, r ₂ is the mass fraction of the monomer M ₂ unit in the polymer P, r _n is the mass fraction The mass fraction of the monomer M _n units in P)

More specifically, since the crosslinkable (meth) acryl-based polymer constituting the component A has a relatively low glass transition temperature of -55 to 0 占 폚, a monomer having a comparatively low glass transition temperature of the homopolymer, (Tg: -55 占 폚), ethyl acrylate (Tg: -24 占 폚) and 2-ethylhexyl acrylate (Tg: -85 占 폚) as a main component, a homopolymer glass A polymer having a desired glass transition temperature can be obtained by appropriately adding a monomer having a relatively high transition temperature, for example, methyl methacrylate (Tg: 105 ° C) and styrene (Tg: 100 ° C) Also, among commercially available (meth) acrylic polymers, those having a desired glass transition temperature may be suitably selected and modified.

In the present specification, "glass transition temperature" means glass transition temperature measured in accordance with JIS K7121 (transition temperature measurement method of plastic).

[2-1E] Content:

The content of the crosslinkable (meth) acryl-based polymer constituting the component A differs depending on the structure of the polymer of the component A, the kind of the adherend, the required adhesive property, and the like. When the total amount of the component A and the component B is 100 parts by mass, 80 to 99.5 parts by mass. When the content is less than 80 parts by mass, the adhesive strength tends to be lowered. On the other hand, if it exceeds 99.5 parts by mass, the durability of the pressure-sensitive adhesive layer tends to be lowered due to lack of cohesive force.

In order to more reliably obtain the above effect, the content of the component A is preferably 85 to 99.5 parts by mass, more preferably 90 to 99.5 parts by mass.

[2-2] Carboxylic acids having polymerizable unsaturated group (component B):

The composition of the present invention comprises at least one (B component) of a carboxylic acid having a polymerizable unsaturated group and oligomers thereof. By containing the component B, the ultraviolet ray curability is not impaired even in the presence of oxygen, and the film strength and adhesion to the substrate are improved, and the pressure-sensitive adhesive composition which is less likely to deteriorate the adhesive property even under the heat- Can be obtained. That is, curing is unnecessary in the manifestation of the adhesive property.

The term "carboxylic acid having a polymerizable unsaturated group" means a carboxylic acid having a polymerizable double bond or a polymerizable triple bond. (Meth) acrylic acid, crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide N-glycolic acid, cinnamic acid and the like .

The term " oligomer of carboxylic acid having a polymerizable unsaturated group " means a polymer of the above-mentioned carboxylic acid having a weight average molecular weight of 10,000 or less. Acrylic acid dimer and acrylic acid polymer having a weight average molecular weight of 10,000 or less.

The content of the component B also varies depending on the structure of the polymer of the component A, the kind of the adherend, the required adhesive property, and the like. However, when the total amount of the component A and the component B is 100 parts by mass, it is required to be 0.5 to 20 parts by mass. When the content is less than 0.5 part by mass, the adhesive durability and optical durability of the adhesive layer tend to be lowered. On the other hand, if it is more than 20 parts by mass, the amount of the free residue at the time of re-peeling tends to increase. To obtain the above effect more reliably, the content of the component B is preferably 0.5 to 15 parts by mass, more preferably 0.5 to 10 parts by mass.

[2-3] Photopolymerization initiator (Component C):

The composition of the present invention contains a photopolymerization initiator (component C) as a component. The photopolymerization initiator means an additive having an action of causing a polymerization reaction by light irradiation if added to the polymerization system. That is, the C component causes polymerization reaction of the A component and the B component with ultraviolet irradiation, and contributes to the formation of a polymer derived from the B component, a crosslinked product between the A component and the B component, and a crosslinked product between the A components. By virtue of these properties, a highly adhesive layer can be formed.

As a photopolymerization initiator, for example, a photopolymerization initiator such as? -Hydroxyacetophenone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals),? -Aminoacetophenone, benzoin compound and the like is known. However, the composition of the present invention contains an acylphosphine oxide compound as a photopolymerization initiator. This is because, when an acylphosphine oxide compound is contained, the color tone deterioration (yellowing) of the pressure-sensitive adhesive layer can be suppressed to an extremely slight level and a pressure-sensitive adhesive excellent in optical characteristics and durability can be formed. When the pressure-sensitive adhesive composition of the present invention is used for bonding an electronic display to a functional film or the like, an ultraviolet absorber (component F) may be contained in some cases. In such a case, It is preferable to use a photopolymerization initiator which causes a polymerization reaction of the component B by ultraviolet rays.

In general, the absorption wavelength of ultraviolet absorber is known to be in the range of about 250 to 380 nm. Therefore, an acylphosphine oxide compound which causes polymerization reaction by irradiation with ultraviolet rays having a wavelength of 380 nm or more can be preferably used.

As a photopolymerization initiator that causes polymerization reaction by irradiation of ultraviolet light having a wavelength of 380 nm or more, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name: Irgacure 369 , Manufactured by Ciba Specialty Chemicals), and the like are also present. However, when a photopolymerization initiator other than the acylphosphine oxide-based compound is used, the yellowing of the adhesive layer or the decrease in the ultraviolet curing property occurs.

The "acylphosphine oxide compound" is a compound having an acylphosphine oxide structure (see Chemical Formula 4 below). That is, as long as it has an acylphosphine oxide structure represented by the following formula (4) in part of its structure, it is included in the " acylphosphine oxide compound " Therefore, among these various materials, a material optimal for the required performance (ultraviolet curing property, color, etc.) as the resin composition can be appropriately selected and used as the C component.

(Wherein R represents an alkyl group which may be substituted or an aryl group which may be substituted)

Examples of the "acylphosphine oxide compound" include bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819, manufactured by Ciba Specialty Chemicals), bis (2,6- Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide (trade name: CGL403, manufactured by Ciba Specialty Chemicals), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Lucirin TPO, (Manufactured by BASF), and the like. Of these, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide is particularly preferable because of excellent curability and little change in color tone of the coating film.

The " acylphosphine oxide compound " also includes a polymer compound. That is, it can be used as a C component of a polymer photopolymerization initiation system in which an acylphosphine oxide structure is introduced into a polymer compound. This polymer photopolymerization initiator includes not only a so-called polymer (weight average molecular weight of about 50,000 or more) but also so-called oligomer (weight average molecular weight of about 500 to 50,000). Such a polymer photopolymerization initiator needs to have at least an acylphosphine oxide structure, but it may also have another photopolymerization initiator structure. For example, in addition to the acylphosphine oxide structure, those having a structure of another photopolymerization initiator, such as a benzoin structure, a hydroxyacetophenone structure, an aminoacetophenone structure or a benzophenone structure, may be mentioned.

The content of the C component differs depending on the structure of the polymer of the A component, the kind of the adherend, the required adhesive property, and the like. When the total amount of the A component and the B component is 100 parts by mass, the content is 0.05 to 3 parts by mass. If the content is less than 0.05 part by mass, the pressure-sensitive adhesive may not be cured or cured may be insufficient. On the other hand, if it exceeds 3 parts by mass, the pressure-sensitive adhesive may be yellowed. In order to more reliably obtain the above effect, the content of the component C is preferably 0.1 to 1 part by mass, more preferably 0.1 to 0.5 part by mass.

In addition, the acylphosphine oxide photopolymerization initiator is susceptible to inhibition by oxygen, and it is difficult to use the acylphosphine oxide photopolymerization apparatus under conditions not subjected to oxygen treatment such as laminating. The inventors of the present invention have found that the ultraviolet curing by an acylphosphine oxide photopolymerization initiator proceeds rapidly in the presence of oxygen by coexisting a component B (a carboxylic acid having a polymerizable unsaturated group such as acrylic acid). As a result, ultraviolet curing with a small amount of a photopolymerization initiator becomes possible under air, thereby enabling the manifestation of the adhesive performance by the acylphosphine oxide photopolymerization initiator. In the pressure-sensitive adhesive composition of the present invention, the amount of the initiator and the amount of the low molecular weight polymer is reduced by extremely reducing the amount of the initiator as compared with the conventional ultraviolet curable pressure-sensitive adhesive, so that it becomes possible to improve the optical properties of the pressure-sensitive adhesive.

[2-4] Silane coupling agent (component D):

The composition of the present invention includes a silane coupling agent (component D) as a component. By mixing the component D, it is possible to exert a good tackiness in the use for bonding with an adherend such as glass. Further, by containing the component D, a pressure-sensitive adhesive composition which is less likely to deteriorate in the adhesive property even under the heat-resistant / moisture-resistant heat-resistant condition can be obtained even when the amount of the component B is small.

As the component D, a compound generally called a " silane coupling agent " can be widely used. Generally, as the silane coupling agent, a silane compound having a reactive functional group such as a glycidoxy group, a methacryloxy group, or an acryloxy group is used. However, in the pressure-sensitive adhesive composition of the present invention, a silane coupling agent having an epoxy functional group is used as the D component. The "epoxy-based functional group" means a functional group having an epoxy ring, and examples thereof include a glycidoxy group. The silane coupling agent having an epoxy-based functional group is preferable in that adhesion to a glass substrate such as a front plate of a plasma display can be improved.

Specific examples of the compound include γ-glycidoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.), γ-glycidoxypropyltriethoxysilane (trade name: KBE- Manufactured by Etsu Chemical Co., Ltd.) and the like), and? -Glycidoxypropylmethyldimethoxysilane, and the like. These silane coupling agents may be used singly or in combination of two or more.

The content of the component D is different depending on the structure of the polymer of the component A, the kind of the adherend, the required adhesive property, and the like, but it is preferably 0.1 to 5 parts by mass when the total amount of the component A and the component B is 100 parts by mass . When the content is less than 0.1 part by mass, the adhesive property may be insufficient in the use for bonding with an adherend such as glass. On the other hand, if it is more than 5 parts by mass, there is a fear that a full residue may be generated upon re-peeling. In order to more reliably obtain the above effect, the content of the component D is preferably 0.5 to 2 parts by mass.

[2-5] Compound (E component) having a polymerizable unsaturated group other than the A component and the B component:

In addition to the above components, the composition of the present invention may further contain, as a component, a compound (E component) having a polymerizable unsaturated group other than the A component and the B component.

Furthermore, the term " compound " is a concept widely including a substance having a polymerizable unsaturated bond. That is, as long as the polymerizable unsaturated bond is present, its chemical structure is not particularly limited, and it may be a monomer or an oligomer.

Examples of the monomer having a polymerizable unsaturated group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i- N-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, (Meth) acrylates such as acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate and tetrahydrofurfuryl acrylate; (Meth) acrylate esters having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate and 4-hydroxybutyl acrylate ; 1,6-hexanediol diacrylate, 1,9-nonanediol acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, etc. Polyfunctional acrylates; Vinyl carboxylates such as vinyl acetate and vinyl propionate; And aromatic vinyls such as styrene and? -Methylstyrene.

However, the monomer having a polymerizable unsaturated group may lower the ultraviolet curing property or may yellow the pressure-sensitive adhesive composition under the condition that the amount of the photopolymerization initiator is reduced as in the present invention. Therefore, in the pressure-sensitive adhesive composition of the present invention, it is preferable to use, as the E component, a polyfunctional oligomer having two or more (meth) acryloyl group-containing functional groups per molecule. By using the polyfunctional oligomer as a constituent component, the crosslinking of the pressure-sensitive adhesive component is further promoted.

The specific structure is not particularly limited, but a monomer having a polymerizable unsaturated bond such as a (meth) acrylate ester is added to a polymer such as a polyester polyol, a polypropylene glycol, an aliphatic polyester, or a bisphenol- Bonded urethane acrylate, and the like. It is preferable to use urethane acrylate and bisphenol epoxy acrylate having an aliphatic polyester skeleton because of compatibility with other components and easy adjustment of adhesion after curing.

Examples of polyfunctional acrylates include NK Oligo UA-340P (trade name, manufactured by Shin-Nakamura Chemical Co., Ltd., basic skeleton: Nippon Kayaku Co., (Basic skeleton: aliphatic polyester), CN-965 (trade name, manufactured by Nippon Kayaku, basic skeleton: aliphatic polyester), Lipoxy VR-77 , Manufactured by Showa Kogyo Co., Ltd., basic skeleton: bisphenol-based epoxy resin) are commercially available. In addition, Viscote # 300 (trade name, manufactured by Osaka Yuki Kagaku, basic skeleton: pentaerythritol) is commercially available. However, those having a desired structure may be appropriately synthesized and used depending on the required performance.

Among them, a polyfunctional oligomer having an aliphatic polyester as a basic skeleton and having two or more (meth) acryloyl group-containing functional groups per molecule and having a weight average molecular weight (Mw) in the range of 1,000 to 10,000, Or the like) or a bisphenol-based epoxy resin as a basic skeleton and having two or more of the (meth) acryloyl functional groups per molecule and a weight average molecular weight (Mw) in the range of 400 to 2000 (for example, , Lipoxy VR-77, etc.).

As the component E, only one of the above compounds may be used alone, or two or more of them may be used in combination.

The content of the component E varies depending on the structure of the polymer of the component A, the kind of the adherend, the required adhesive property, and the like, but when the total amount of the component A and the component B is 100 parts by mass, it is required to be 0 to 20 parts by mass . Particularly when the polyfunctional oligomer is used as the component E, it is preferable that the polyfunctional oligomer is contained in an amount of 0.5 to 20 parts by mass. If the content of the polyfunctional oligomer is less than 0.5 part by mass, adjustment of the adhesive strength may be difficult. On the other hand, if it exceeds 20 parts by mass, the adhesive strength tends to be remarkably lowered. In order to more reliably obtain the above effect, the content of the polyfunctional oligomer is preferably 0.5 to 15 parts by mass, more preferably 0.5 to 10 parts by mass.

[2-6] Ultraviolet absorber (component F):

The composition of the present invention may contain an ultraviolet absorber (component F) in addition to the above components. By mixing the component F, it is possible to shield ultraviolet rays having strong chemical action and suppress the oxidation or deterioration of substances existing on the lower layer side of the adhesive layer or deterioration (discoloration, fading, embrittlement, etc.) (Hereinafter may be referred to as " ultraviolet ray shielding property ").

As the F component, it is preferable to contain a benzophenone-based compound having a lambda _max in a wavelength range of 350 to 400 nm. The "benzophenone compound" is a compound having a benzophenone skeleton represented by the following formula (5). That is, as long as the compound has a benzophenone skeleton represented by the following formula (5) in part of its structure, it is included in the "benzophenone compound" in the present invention, despite the structure of the other part. Therefore, among these various materials, a material optimal for the required performance (ultraviolet curing property, color, etc.) as the resin composition can be appropriately selected and used as the F component.

However, in the composition of the present invention, it is preferable that the absorption spectrum pattern of the C component and the F component do not agree with each other in order to impart ultraviolet shielding property without inhibiting the action of the photopolymerization initiator (component C). In the composition of the present invention, it is preferable to use a C component having an absorption wavelength region within a range of 200 to 440 nm and an F component having an absorption wavelength region within a range of 200 to 415 nm.

In other words, as component F, it is preferable to use that λ _max is in the λ _max with different wavelength ranges of the C component. For example, when a C component having a _maximum of lambda within a range of 240 to 250 nm is used, it is preferable to use an ultraviolet absorbent having a lambda _max in the range of 280 to 300 nm, and as the component C of 280 to 300 nm in the case of using those having a λ _max in the range of 380 to 410 nm as is preferred, and component C using an ultraviolet absorber having a λ _max in the range, the 310 to 330 nm when using those having a λ _max in the range, 340 It is preferable to use an ultraviolet absorber having a lambda _max within the range of 380 nm to 380 nm.

Examples of the photopolymerization initiator in which the absorption wavelength region is in the range of 200 to 440 nm include α-hydroxyacetophenone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals), α-aminoacetophenone, Acylphosphine oxide compounds (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and the like), and the like.

On the other hand, examples of the ultraviolet absorber having an absorption wavelength range within a range of 200 to 415 nm (i.e., an ultraviolet absorber having a _maximum at a wavelength region of 280 to 380 nm) include 2,2 ', 4,4'-tetra Hydroxybenzophenone (trade name: Dainsob P-6, manufactured by Daiwa Gosei Co.), 2,2'-dihydroxy-4,4'-dimethoxybenzophenone (trade name: , 2,4-dihydroxybenzophenone (trade name: SISOV 100, manufactured by Cipro Gage Inc.), and the like.

Therefore, in the composition of the present invention, it is preferable to use a combination of the photopolymerization initiator and the ultraviolet absorber. Among them, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide and 2,2'-dihydroxy-4,4'-dimethoxybenzoic acid are preferred because of the difficulty of color deterioration (yellowing) Lt; / RTI > benzophenone is preferred.

Although the content of the F component differs depending on the kind and amount of the C component, it is preferably 0.1 to 15 parts by mass when the total amount of the A component and the B component is 100 parts by mass. If the content is less than 0.1 part by mass, the ultraviolet blocking effect may be insufficient. On the other hand, if it exceeds 15 parts by mass, the pressure-sensitive adhesive may not be cured or cured may be insufficient. In order to more reliably obtain the above effect, the content of the F component is preferably 0.5 to 10 parts by mass, more preferably 1 to 5 parts by mass.

[2-7] Solvent:

The composition of the present invention may contain a solvent as a constituent. By containing a solvent, it is possible to effectively improve the coating ability, and to effectively prevent problems such as the occurrence of unevenness at the time of coating.

The type of the solvent is not particularly limited, and can be appropriately selected in consideration of miscibility with other components. For example, aromatic solvents such as toluene and xylene; Ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and 2-methyl-5-hexanone; Ester solvents such as ethyl acetate, butyl acetate and ethyl lactate; Halogen solvents such as methyl chloride, dichloromethane and dichloroethane; Alcohol solvents such as ethanol and isopropanol; Glycol ether solvents such as ethylene glycol ethyl ether, propylene glycol methyl ether, propylene glycol n-propyl ether and propylene glycol methyl ether acetate, cellosolve acetate, methyl cellosolve, ethyl cellosolve, n- , cellosolve such as i-butyl cellosolve and n-propyl cellosolve, and the like.

Among these solvents, methyl ethyl ketone and ethyl acetate are preferably used, and methyl ethyl ketone is particularly preferably used because it is easy to reduce the residual solvent concentration. These solvents may be used alone or in combination of two or more.

Although the content of the solvent differs depending on the structure of the polymer of the component A, the kind of the adherend, the required adhesive property, and the like, it is preferable that the solvent is contained so that the solid content concentration of the adhesive composition is in the range of 20 to 50 mass%. If the solid content concentration of the pressure-sensitive adhesive composition is less than 20% by mass, adjustment of the coating film thickness may be difficult. On the other hand, if the solid content exceeds 50% by mass, the viscosity of the composition increases, and the coating property may be deteriorated.

Further, the content of the solvent can be adjusted based on the viscosity of the composition. Specifically, the amount of the solvent is adjusted so that the viscosity of the composition (25 ° C) is 100 to 5000 mPa · s, preferably 300 to 2000 mPa · s. However, the solvent is not limited to those added when adjusting the viscosity of the composition as described above. For example, when the component A is solution-polymerized and the solvent is used in the preparation of the composition without distillation, the polymerization solvent of the component A is also included in the solvent.

[2-8] Other additives:

The composition of the present invention may contain, in addition to the above components, various additives such as an antioxidant, a defoaming agent, a leveling agent, an adhesion promoter, a tackifier, a light stabilizer, an antistatic agent, a surfactant, a storage stabilizer, a thermal polymerization inhibitor, Or the like may be added to the pressure-sensitive adhesive composition, if necessary. The content of these additives can be appropriately determined within a range that does not impair the purpose of the composition of the present invention.

Further, unlike the prior art, the composition of the present invention does not require addition of a heat crosslinking agent. By not using a heat crosslinking agent, operation and curing of the required two-liquid mixture are unnecessary in a two-pack type solvent-based pressure-sensitive adhesive (generation of a lotion).

The term "thermal cross-linking agent" means a substance which accelerates the crosslinking reaction by heating and exhibits adhesive property. However, in the composition of the present invention, the adhesive property can be expressed without using these heat crosslinking agents. Hereinafter, as a reference, a heat crosslinking agent used in a two-pack type solvent-based pressure-sensitive adhesive may be mentioned.

Bisphenol A epichlorohydrin type epoxy resin; Ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylol propane triglycidyl ether, sorbitol Epoxy compounds such as polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidylerythritol, and diglycerol polyglycidyl ether; Tetramethylolmethane-tri-? -Aziridinylpropionate, trimethylolpropane-tri-? -Aziridinylpropionate, N, N'-diphenylmethane-4,4'-bis Aziridine-based compounds such as N, N'-hexamethylene-1,6-bis (1-aziridinecarboxamide);

Melamine-based compounds such as hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexabutoxymethylmelamine, hexapentyloxymethylmelamine, hexahexyloxymethylmelamine and melamine resin; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane- (Isocyanatomethyl) cyclohexane, tetramethyl xylylene diisocyanate, 1,5-naphthalene diisocyanate, tolylene diisocyanate adduct of trimethylol propane, xylylene diisocyanate of trimethylol propane, isophorone diisocyanate, 1,3- Adducts of diphenylmethane-4,4-diisocyanate adduct of trimethylolpropane, isophorone diisocyanate adduct of trimethylolpropane, triphenylmethane triisocyanate, methylene bis (4-phenylmethane) triisocyanate and the like, Based compound;

Aldehyde-based compounds such as glyoxal, malondialdehyde, succinic aldehyde, maladialdehyde, glutardialdehyde, formaldehyde, acetaldehyde and benzaldehyde; Amine compounds such as hexamethylenediamine, triethylenediamine, polyethyleneimine, hexamethylenetetraamine, diethylenetriamine, triethyltetramine, isophoronediamine, amino resin, and polyamide; And metal chelate compounds in which acetylacetone or acetoacetyl ester is coordinated to metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium.

[3] Production method:

The composition of the present invention can be obtained by mixing A component, B component, C component, D component, E component, F component, solvent and other additives as necessary in a predetermined ratio.

[4] How to use:

The composition of the present invention can be coated as it is. For example, after coating the surface of the adherend with a conventionally known coating apparatus such as an applicator, the organic solvent is removed by drying, and then ultraviolet rays are irradiated according to the kind of the component C (photopolymerization initiator) .

Examples of the adherend to which the composition of the present invention can be applied include polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polysulfone, polymethyl methacrylate, polystyrene, polybutadiene, ABS resin, AS Thermoplastic resins such as resin, AES resin, polyimide resin, aliphatic polyamide resin (trade name: nylon), cellulose, nitrocellulose, and triacetylcellulose; Thermosetting resins such as phenol formaldehyde resin, cresol formaldehyde resin, melamine resin and urea resin; Inorganic materials such as glass, ceramics, and metals. Further, the adherend may be subjected to surface treatment depending on the application.

The composition of the present invention exhibits adhesive force upon irradiation with ultraviolet rays. The wavelength of ultraviolet rays is not particularly limited, but it is preferable to irradiate ultraviolet rays having a wavelength of 200 to 400 nm. Specific examples of the light source include, for example, ultra high-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, and high-power metal halide lamps. The ultraviolet irradiation condition is not particularly limited, but is preferably, but not limited to, 100 to 600 mW / cm ² (20 to 150 mJ / cm ² ) in the case of a high-pressure mercury lamp.

The adhesive strength is preferably about 20 to 25 N / 25 mm as in the case of the conventional thermosetting type. In this case, it is preferably 20 N / 25 mm or less, and particularly preferably 15 N / 25 mm or less. This adhesive strength can be adjusted depending on the weight average molecular weight (Mw) of the component A, the glass transition temperature (Tg), the content of the (meth) acryloyl group / alkoxysilyl group, and the kind and amount of the E component.

<Examples>

Hereinafter, the ultraviolet curing pressure-sensitive adhesive composition of the present invention will be described in more detail with reference to Examples. However, these embodiments are only illustrative of some embodiments of the present invention. Therefore, the present invention should not be construed as being limited to these embodiments.

[1] Synthesis of base polymer of component A:

First, a (meth) acrylic polymer serving as an A component base polymer was prepared.

(Reference Example 1)

Neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer was charged with 67 parts by mass of ethyl acrylate, 10 parts by mass of acrylonitrile, 23 parts by mass of 2-hydroxyethyl methacrylate, 233 parts by mass were charged, and the mixture was heated under a nitrogen stream to start heating and refluxing. Then, 0.1 part by mass of 2,2'-azobisisobutyronitrile (hereinafter referred to as &quot; AIBN &quot;) was added as a polymerization initiator, and the mixture was reacted at 90 DEG C for 5 hours to obtain a solution of the (meth) acrylic polymer (Weight average molecular weight: 19.8 million, glass transition temperature: 0 占 폚, solid content concentration: 30 mass%, viscosity: 600 mPa 占 퐏 / 25 占 폚).

(Reference Example 2)

87 parts by mass of ethyl acrylate, 3.5 parts by mass of acrylonitrile, 9.5 parts by mass of 2-hydroxyethyl acrylate and 233 parts by mass of methyl ethyl ketone 233 were added to a four-necked round bottom flask equipped with a reflux condenser, a stirrer, And the mixture was heated under a nitrogen stream to initiate heating and refluxing. Thereafter, 0.03 parts by mass of AIBN was added as a polymerization initiator, and the mixture was allowed to react at 80 占 폚 for 6 hours to obtain a (meth) acrylic polymer (P-2) solution (weight average molecular weight: 274,000, glass transition temperature: , Viscosity: 400 mPa 占 퐏 / 25 占 폚).

(Reference Example 3)

300 parts by mass of water was put into a four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer, and 0.7 part by mass of polyvinyl alcohol as a dispersion stabilizer was dissolved by stirring. To this solution was added a monomer mixture composed of 33.4 parts by mass of ethyl acrylate, 50 parts by mass of butyl acrylate, 3 parts by mass of methyl methacrylate and 13.6 parts by mass of 2-hydroxyethyl methacrylate, and 1 part by mass of AIBN as a polymerization initiator To prepare a suspension. The suspension was heated under a nitrogen stream to initiate heating and refluxing. After reacting at 80 ° C for 4 hours, the reaction product was subjected to solid-liquid separation, thoroughly washed with water and then dried at 70 ° C for 12 hours using a drier to obtain a solid polymer (P-3) 42.3 million, glass transition temperature -30 占 폚).

(Reference Example 4)

300 parts by mass of water was put into a four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer, and 0.4 part by mass of polyvinyl alcohol as a dispersion stabilizer was dissolved by stirring. 54.4 parts by mass of ethyl acrylate, 29 parts by mass of butyl acrylate, 3 parts by mass of methyl methacrylate and 13.6 parts by mass of 2-hydroxyethyl acrylate, and 0.5 parts by mass of AIBN as a polymerization initiator were added , A suspension was prepared. The suspension was heated under a nitrogen stream to initiate heating and refluxing. After reacting at 80 DEG C for 6 hours, the reaction product was subjected to solid-liquid separation, washed sufficiently with water and then dried at 70 DEG C for 12 hours by using a drier to obtain a solid dispersion of (meth) acrylic polymer (P- 60.3 million, glass transition temperature -30 占 폚).

(Reference Example 5)

97 parts by mass of butyl acrylate, 3 parts by mass of 2-hydroxyethyl acrylate and 233 parts by mass of methyl ethyl ketone were charged into a four-neck round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, And heated under reflux to initiate heating and refluxing. (P-5) solution (weight average molecular weight: 798,000, glass transition temperature: -55 占 폚, solid concentration: 30 mass%) was obtained by adding 0.5 mass part of AIBN as a polymerization initiator and reacting at 80 占 폚 for 6 hours. , Viscosity: 4500 mPa 占 퐏 / 25 占 폚).

(Reference Example 6)

A four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet, and a thermometer was charged with 70 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of acrylonitrile, 15 parts by mass of 2-hydroxyethyl methacrylate, And 400 parts by mass of methyl ethyl ketone were charged, and heating and refluxing were started by heating in a nitrogen stream. (P-6) solution (weight average molecular weight: 152.3 million, glass transition temperature: -55 占 폚, solid content concentration: 20 mass%) was obtained by adding 0.01 mass part of AIBN as a polymerization initiator, , And a viscosity of 8000 mPa ((25 캜)).

(Reference Example 7)

Polymer (P-7) was used as a commercially available acrylic copolymer (trade name: Alphon UH2000, solid content 100 mass%, weight average molecular weight 1.1 million, glass transition temperature -55 deg.

(Reference Example 8)

100 parts by mass of toluene was added to a four-necked round bottom flask equipped with a reflux condenser, a stirrer, a nitrogen gas inlet and a thermometer, and then 97.5 parts by mass of 2-ethylhexyl acrylate, 1.5 parts by mass of 2-hydroxyethyl acrylate, Acrylic acid polymer (P-8) solution (weight-average molecular weight: 48.6 million, glass transition temperature: 25 ° C) was obtained by dropwise addition of a mixed solution of 1 part by mass of acrylic acid and 2 parts by mass of AIBN in a stream of nitrogen over 2 hours while reacting at 100 ° C for 8 hours A temperature of -83 캜, a solid content concentration of 50 mass%, and a viscosity of 7400 mpa s / 25 캜).

(Reference Example 9)

5 parts by mass of acrylic acid, 95 parts by mass of butyl acrylate, 80 parts by mass of ethyl acetate, 40 parts by mass of acetone and 0.03 mass of AIBN as a polymerization initiator were added to a four-neck round bottom flask equipped with a reflux condenser, a stirrer, (P-9) solution (weight average molecular weight: 183.6 million, glass transition temperature: -50 占 폚, solid content concentration: 16 占 퐉), and the mixture was stirred at room temperature for 3 hours under a stream of nitrogen. Mass%, viscosity: 9000 mPa 占 퐏 / 25 占 폚).

[2] Synthesis of crosslinkable (meth) acrylic polymer (component A)

Then, a reactive sensitizer was introduced into the base polymer to obtain a crosslinkable (meth) acrylic polymer (A-1).

(Reference Example 10)

0.05 parts by mass of dibutyltin laurate relative to 100 parts by mass (in terms of solid content) of the (meth) acrylic polymer (P-1) and 0.3 parts by mass of 2 -Methacryloyloxyethyl isocyanate (trade name: CALENS MOI, manufactured by Showa Denko Co., Ltd.) was charged, and the mixture was reacted at 50 ° C for 8 hours. The completion of the reaction was confirmed by disappearance of the isocyanate group by titration analysis of the reaction solution. Thereby, a (meth) acryloyl group was introduced into the acrylic polymer (P-1), and a solution of a crosslinkable (meth) acrylic polymer (A-1) (weight average molecular weight 19,900, glass transition temperature 0 캜, Mass%, viscosity of 600 mPa 占 퐏 / 25 占 폚).

(Reference Examples 11 to 23)

(Meth) acrylic polymer (A-2) to (A-10) were obtained in the same manner as in Reference Example 8, except that the kind of the base polymer and the type and amount of the (meth) acrylic compound having an isocyanate group were changed. , (A-12) to (A-15). Table 1, Table 3, Table 5 and Table 7 show the charging ratios thereof.

(Reference Example 24)

The (meth) acrylic polymer (P-3) synthesized in Reference Example 3 was dissolved in 233 parts by mass of methyl ethyl ketone to obtain a (meth) acrylic polymer solution (solid concentration 30% by mass). , 0.05 parts by mass of dibutyltin laurate, 0.25 parts by mass of 2-acryloyloxyethyl isocyanate (trade name: Carlen AOI, manufactured by Showa Denko K.K.) and 100 parts by mass of alkoxysilane (based on 100 parts by mass of the (meth) acrylic polymer And 0.1 part by mass of the compound (3-isocyanate propyltriethoxysilane, trade name: KBE-9007, manufactured by Shin-Etsu Chemical Co., Ltd.) were charged and reacted at 50 ° C for 8 hours. The reaction was terminated when the disappearance of the isocyanate group was confirmed by titration analysis of the reaction solution to obtain a solution of a crosslinkable (meth) acrylic polymer (A-11) (weight average molecular weight: 42.5 million, glass transition temperature: , Viscosity 500 mPa s / 25 캜).

(Reference Example 25)

2 parts by mass of 2-methacryloyloxyethyl isocyanate (Carlene MOI, manufactured by Showa Denko KK), 0.04 parts by mass of hydroquinone, and 100 parts by mass of dibutyltin oxide (P-8) were added to the (meth) And 0.04 parts by mass of laurate were added, and the denaturation reaction was carried out at the same temperature for 8 hours. Then, toluene was distilled off to obtain a crosslinkable (meth) acrylic polymer (A-16) having a weight average molecular weight of 493,000 and a glass transition temperature of -83 캜 by reducing the residual solvent to 1% or less.

(Reference Example 26)

A mixed solvent of 50 parts by mass of ethyl acetate / 50 parts by mass of toluene was added to 100 parts by mass (in terms of solid content) of the (meth) acrylic polymer (P-9) in the (meth) acrylic polymer (P- 0.08 parts by mass of dibutyltin dilaurate and 5.4 parts by mass of 2-methacryloyloxyethyl isocyanate were charged and reacted at 65 ° C for 8 hours. Finally, this reaction solution was diluted with toluene to obtain a solution of a crosslinkable (meth) acrylic polymer (A-17) (weight average molecular weight: 185.3 million, glass transition temperature -50 占 폚, solid content concentration of 13 mass%, viscosity of 9500 mPa 占 퐏 / 25 &lt; 0 &gt; C).

The quality of the component A was evaluated by the following method.

[Weight average molecular weight]

The weight average molecular weight of the polymer in terms of polystyrene was measured by the GPC method.

[Glass transition temperature]

The glass transition temperature of the polymer was measured in accordance with JIS K7121 (transition temperature measurement method of plastic).

[Content of methacryloyl group and triethoxysilyl group]

The methacryloyl group content and triethoxysilyl group content of the polymer were quantified by the acid base titration method. Specifically, the obtained polymer is mixed with di-n-butylamine (DBA), the unreacted isocyanate group of the (meth) acrylic compound or alkoxysilane compound is reacted with DBA, and the amount of DBA consumed is quantitatively determined by reverse titration with hydrochloric acid Respectively.

[Preparation of UV-curable pressure-sensitive adhesive composition]

(Example 1)

7 parts by mass of acrylic acid (B-1 component), 4 parts by mass of 2,4,6-trimethyl (meth) acrylic acid (B-1 component) were added to 93 parts by mass of a solid component in a solution of crosslinkable (meth) acrylic polymer (A- 0.5 part by mass of benzoyl-diphenylphosphine oxide (component C-1, product name: Lucirin TPO, BASF), 3 g of glycidoxypropyltrimethoxysilane (component D-1, trade name: KBM- Manufactured by Etsu Chemical Co., Ltd.) were mixed to prepare an ultraviolet ray-curable pressure-sensitive adhesive composition.

(Examples 2 to 27 and Comparative Examples 1 to 23)

Except that the components (A-1 to A-15) synthesized in Reference Examples 10 to 26 were used and the kinds and amounts of the components were changed to the compositions shown in Tables 1 to 12, In the same manner, a UV-curable pressure-sensitive adhesive composition was prepared. The following components were used as the respective components.

<Component B>

B-1: Acrylic acid (manufactured by Osaka Yuki Kogyo Kagaku Co., Ltd.)

B-2: Acrylic acid dimer (trade name: cypolymer beta-CEA-J, manufactured by Rhodia)

<Component C>

C-1: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (trade name: Lucirin TPO, BASF)

C-2: Synthesis of oxy-phenyl-acetic acid 2- [2-oxo-2-phenyl-acetoxy-ethoxy] -ethyl ester and oxy-phenyl- acetic acid 2- [2-hydroxy-ethoxy] Mixture (trade name: Irgacure 754, manufactured by Ciba Specialty Chemicals)

C-3: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one (Irgacure 907, Ciba Specialty Chemicals)

C-4: 2,2-dimethoxy-1,2-diphenylethan-1-one (trade name: Irgacure 651, manufactured by Ciba Specialty Chemicals)

C-5: 1-Hydroxy-cyclohexyl-phenyl-ketone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals)

<Component D>

D-1: 3-glycidoxypropyltrimethoxysilane (trade name: KBM-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

D-2: 3-glycidoxypropyltriethoxysilane (trade name: KBE-403, manufactured by Shin-Etsu Chemical Co., Ltd.)

D-3: N-2 (aminoethyl) 3-aminopropyltrimethoxysilane (trade name: KBM-603, manufactured by Shin-Etsu Chemical Co., Ltd.)

D-4: 3-mercaptopropyltrimethoxysilane (trade name: KBM-803, manufactured by Shin-Etsu Chemical Co., Ltd.)

<Component E>

E-1: Aliphatic polyester skeleton urethane acrylate (trade name: EB270, manufactured by Daicel-Cotech)

E-2: Bisphenol-based epoxy resin skeleton urethane acrylate (trade name: Lipoxy VR-77, manufactured by Showa Kobunshi Co., Ltd.)

E-3: 2-ethylhexyl acrylate

E-4: 1,6-hexanediol diacrylate (trade name: NK Ester A-HD, Shin Nakamura Chemical Industry Co., Ltd.)

<Component F>

F-1: 2,2 ', 4,4'-tetrahydroxy-benzophenone (trade name: Dainsob P-6, manufactured by Daiwa Kasei)

&Lt; Heat crosslinking agent &

Polyisocyanate (trade name: Colonate L, manufactured by Nippon Polyurethane Industry Co., Ltd.)

<Solvent>

Methyl ethyl ketone (manufactured by Kishida Chemical Co., Ltd.)

Toluene (manufactured by Kishida Chemical Co., Ltd.)

Ethyl acetate (manufactured by Kishida Chemical Co., Ltd.)

Acetone (manufactured by Kishida Chemical Co., Ltd.)

The quality of the ultraviolet curable pressure sensitive adhesive composition was evaluated by the following method.

[Handling (property of extending liquid like thread)]

The composition to be evaluated was a coating liquid having a solid content concentration of 30 mass%, and a coating liquid was adhered to the glass rod, and the state when the coating liquid dropped from the glass rod was visually evaluated. When the coating liquid dropped from the glass rod, the glass rod completely separated from the coating liquid, and when dropped in a droplet state, &quot;? &Quot; (good), the glass rod and the coating liquid were not completely separated, And when it dropped, it was evaluated as &quot; x &quot; (defective).

[Coating property (pottery)]

The composition to be evaluated was a coating liquid having a solid content concentration of 30%, and this coating liquid was applied to the silicon-treated surface of a PET film (release film) having a thickness of 38 占 퐉 which had been subjected to silicone treatment on one side by an applicator, After drying for 2 minutes, ultraviolet rays were irradiated under conditions of 500 mW / cm ² · 80 mJ / cm ² , and the coating film was ultraviolet cured to form a pressure-sensitive adhesive layer. Thereafter, the pressure-sensitive adhesive layer of the release film was bonded to a PET film (thickness: 100 μm, total light transmittance: 91%, haze value: 0.3 or less, referred to as "base film" Thereby forming a pressure-sensitive adhesive layer having a thickness of 15 mm. The ultraviolet ray was irradiated by a high-pressure mercury lamp. Ultraviolet rays having a wavelength of 200 to 400 nm are irradiated by a high-pressure mercury lamp.

The evaluation of the coatability was carried out by checking whether or not a paint coat was formed when the coating liquid was applied to the surface of the release film by an applicator. Specifically, the gap width of the applicator was adjusted so that the thickness of the coating film was 15 μm, and the coating was performed at 20 m / min. The number of potted roots generated at that time was evaluated by the number of occurrences per 15 cm of the coating width. (Very good) in the case of the coated root 0, "O" in one case, and "x" (poor) in the case of two or more cases.

[Gel fraction]:

The gel content of the composition to be evaluated was weighed by Soxhlet extraction. Specifically, Soxhlet extraction using tetrahydrofuran as a solvent was performed for 8 hours, and the mass% of the insoluble matter that was not extracted was represented by the gel content (% by mass). (Good) when the gel content was 60% by mass or more, "good" (fairly good), 55% by mass or more and less than 60% by mass, and "good" (poor) when the gel content was less than 55% by mass. When the gel content is 55% by mass or more, the pressure-sensitive adhesive is not pushed out when the pressure-sensitive adhesive film is wound, and there is no pressing trace by the protective film such as the embossing film.

[Production of adhesive film]

A solution (solid content concentration: 30%) of the ultraviolet ray-curable pressure-sensitive adhesive composition of the examples and comparative examples was applied to the silicone-treated surface of the release film and dried at 80 ° C for 2 minutes. Then, ultraviolet rays (UV irradiation condition: 500 mW / cm ² , 80 mJ / cm ² ) to form a pressure-sensitive adhesive layer having a thickness of 15 μm. Subsequently, a pressure-sensitive adhesive layer of the release film was bonded to the base film, and the release film was peeled off to obtain a base film (pressure-sensitive adhesive film) having a pressure-sensitive adhesive layer formed thereon.

In Comparative Example 21-1, on the silicon-treated side of the release film, the ultraviolet-curing pressure-sensitive adhesive composition of Comparative Example 21-1 (solid content concentration: 100%) was applied as it was without dilution with a solvent, (UV irradiation condition: 500 mW / cm ² , 80 mJ / cm ² ) with the pressure-sensitive mercury lamp adjusted to a thickness of 20 μm. Thereafter, the release film was peeled off to obtain a base film (pressure-sensitive adhesive film) having a pressure-sensitive adhesive layer formed thereon.

In Comparative Example 21-2, the ultraviolet-curing pressure-sensitive adhesive composition of Comparative Example 21-2 (solid content concentration: 100%) was applied directly to the silicone-treated surface of the release film without diluting it with a solvent. Ultraviolet rays (UV irradiation conditions: 500 mW / cm ² , 80 mJ / cm ² ) to form a pressure-sensitive adhesive layer having a thickness of 20 μm. Subsequently, a pressure-sensitive adhesive layer of the release film was bonded to the base film, and the release film was peeled off to obtain a base film (pressure-sensitive adhesive film) having a pressure-sensitive adhesive layer formed thereon.

For Comparative Example 22-1, a solution (solid content concentration of 30%) of the ultraviolet-curable pressure-sensitive adhesive composition of Comparative Example 22-1 was coated on the silicon-treated surface of the release film and heated at 90 占 폚 for 3 minutes to form a film having a thickness of 20 占 퐉 Sensitive adhesive layer was formed. Subsequently, the pressure-sensitive adhesive layer of the release film was bonded to the base film to form a laminated state, and ultraviolet ray irradiation was performed with a high-pressure mercury lamp. The film was cured at 40 캜 for 4 days under drying conditions, and the release film was peeled off to obtain a base film (pressure-sensitive adhesive film) having a pressure-sensitive adhesive layer formed thereon.

In Comparative Examples 22-2 and 22-3, a base film (pressure-sensitive adhesive film) having a pressure-sensitive adhesive layer formed by subjecting the pressure-sensitive adhesive layer of the release film to ultraviolet light irradiation, &Lt; / RTI &gt; Further, the curing was not performed.

In Comparative Example 23-1, a solution (solid content concentration of 30%) of the thermosetting adhesive composition of Comparative Example 23-1 was coated on the silicon-treated surface of the release film and heated at 90 占 폚 for 3 minutes to form a film having a thickness of 20 占 퐉 Sensitive adhesive layer was formed. Subsequently, after the pressure-sensitive adhesive layer of the release film was bonded to the base film, the release film was peeled off without curing to obtain a base film (pressure-sensitive adhesive film) having the pressure-sensitive adhesive layer formed thereon. This adhesive film was bonded to an alkali glass. As for Comparative Example 23-2, an adhesive film was obtained in the same manner as in Comparative Example 23-1, except that the cured film was cured at 40 占 폚 under dry conditions for 4 days.

[Adhesion]

In the same manner as in the evaluation of the coating properties, except for Comparative Examples 21-1 to 21-2, 22-1 to 22-3, and 23-1 to 23-2, on the surface of the base film, (Pressure-sensitive adhesive layer).

Thereafter, a base material (adhesive film) having the pressure-sensitive adhesive layer formed thereon was bonded to an alkali glass (general hard glass) to form a laminate. The adhesive strength (initial adhesion) between the adhesive film and the alkali glass at a point of time 1 hour after formation of the laminate was measured by a 180 ° peel test described in JIS Z0237 (Test Method for Adhesive Tape / Adhesive Sheet). At this time, the residue of the alkali on the surface of the alkali glass was visually evaluated.

(Very good), those having an initial adhesion of 5 N / 25 mm or more and 15 N / 25 mm or less, those having a Young's modulus of less than 5 N / 25 mm and a Young's modulus of 15 N / (Slightly bad), those less than 3 N / 25 mm and those having a thickness of more than 30 N / 25 mm were evaluated as &quot; X &quot; (good) Defective). The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1. The results are shown in Table 1.

[Heat resistance]

In the same manner as in the evaluation of the tackiness, a base film (pressure-sensitive adhesive film) on which a pressure-sensitive adhesive layer was formed was bonded to an alkali glass (general hard glass) to form a laminate. The laminate was exposed for 1000 hours under conditions of high temperature (80 DEG C), and then the adhesive strength between the adhesive film and the alkali glass was measured by a 180 DEG peel test described in JIS Z0237 (adhesive tape and pressure sensitive adhesive sheet test method) . At this time, the residue of the alkali on the surface of the alkali glass was visually evaluated.

In the evaluation of the tackiness, the case where the adhesive retention R ₁ calculated by the following formula (2) is within a range of 100 to 200% from the adhesive force T ₁ after exposure in the normal state and the adhesive force T ₂ after exposure under the high- ⊚ "(good), a case of less than 100% and a case of more than 200% were evaluated as" x "(defective). Further, regarding the paste residue, the case where the paste residue was not visually observed was evaluated as &quot;?&Quot; (good), and the case where the paste residue was visually observed was evaluated as &quot; x &quot; (defective).

&Quot; (2) &quot;

R ₁ = (T ₂ / T ₁ ) × 100

(Where, T _1: adhesive force after exposed under a high temperature condition (N / 25 mm), R 1:: Initial adhesion (N / 25 mm), T 2 in the normal state, the adhesive holding ratio (%))

[Humidity Resistance]

In the same manner as in the evaluation of the tackiness, a base film (pressure-sensitive adhesive film) on which a pressure-sensitive adhesive layer was formed was bonded to an alkali glass (general hard glass) to form a laminate. The laminate was exposed for 1000 hours under the conditions of high temperature and high humidity (temperature: 60 DEG C, humidity: 90%), and the adhesive strength between the adhesive film and the alkali glass was measured according to JIS Z0237 (adhesive tape / adhesive sheet test method) Lt; RTI ID = 0.0 &gt; 180 &lt; / RTI &gt;

In the evaluation of the tackiness, when the adhesive retention R ₂ calculated from the following formula (3) is within a range of 100 to 200% from the adhesive force T ₁ after exposure in a normal state and the adhesive force T ₃ after exposure under a high- Was evaluated as &quot;?&Quot; (good), and when it was less than 100% and more than 200%, it was evaluated as &quot; Further, regarding the paste residue, the case where the paste residue was not visually observed was evaluated as &quot;?&Quot; (good), and the case where the paste residue was visually observed was evaluated as &quot; x &quot; (defective).

&Quot; (3) &quot;

R ₂ = (T ₃ / T ₁ ) × 100

(Where, T _1: the initial adhesive strength in normal condition (N / 25 mm), T 3: high temperature and adhesive force after exposed under high humidity (N / 25 mm), T 2 (N / 25 mm), R 2: Adhesive retention (%))

[Color difference]

In the same manner as in the evaluation of the tackiness, a base film (pressure-sensitive adhesive film) on which a pressure-sensitive adhesive layer was formed was bonded to an alkali glass (general hard glass) to form a laminate. The color difference (b *) at 25 ° C of this laminate was measured by a color difference meter (trade name: Spectrophotometer SQ-2000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) ). (Good), and those having an initial color difference (b *) of 0.3 or less were evaluated as &quot;? &Quot; (very good). However, in the composition of Example 27 in which the ultraviolet absorber is blended, the ultraviolet absorbent itself is yellow and the color difference index is different. Therefore, the initial color difference (b *) is 1 or less, X &quot;.

The color difference was also measured for the laminate after the heat resistance test and the laminate after the heat and humidity resistance test (hereinafter sometimes referred to as "endurance color difference"). (Excellent), those having a difference between the initial color difference and the initial color difference of less than 0.1 were evaluated as &quot;? &Quot; (very good) Respectively.

[Total light transmittance]

In the same manner as in the evaluation of the tackiness, a base film (pressure-sensitive adhesive film) on which a pressure-sensitive adhesive layer was formed was bonded to an alkali glass (general hard glass) to form a laminate. The total light transmittance of this laminate at 25 캜 was measured by a turbidimeter (trade name: HAYETSMER HM-150, manufactured by Murakami Shikigai Co., Ltd.) (hereinafter referred to as "initial total light transmittance" has exist). (Good), and those having an initial total light transmittance of 90% or more were evaluated as &quot;? &Quot; (very good).

The total light transmittance was also measured for the laminate after the heat resistance test and the laminate after the heat and humidity resistance test (hereinafter sometimes referred to as &quot; durability total light transmittance &quot;). The durability total light transmittance was evaluated as &quot;? &Quot; (very good), &quot; Good &quot; ).

[Hayes]

In the same manner as in the evaluation of the tackiness, a base film (pressure-sensitive adhesive film) on which a pressure-sensitive adhesive layer was formed was bonded to an alkali glass (general hard glass) to form a laminate. The haze of this laminate at 25 캜 was measured by a turbidimeter (trade name: Hazemeter HM-150, manufactured by Murakami Shikigai Co., Ltd.) (hereinafter sometimes referred to as "initial haze"). As to the initial haze, "O" (fairly good), "good" (fairly good), "good" and "poor" were evaluated.

The haze of the laminate after the heat resistance test and the laminate after the heat and humidity resistance test was also measured by the same method (hereinafter sometimes referred to as &quot; durability haze &quot;). The durability haze was evaluated as "good" when the difference from the initial haze was "good" (excellent), "good" when the difference was 0.1 or more, and "good" when the difference was 0.3 or less.

[UV protection property]

With respect to the composition obtained in Example 27, the ultraviolet barrier property was evaluated by the following method. First, in the same manner as in the evaluation of the tackiness, a base film (pressure-sensitive adhesive film) having a pressure-sensitive adhesive layer formed thereon was bonded to an alkali glass (general hard glass) to form a laminate. Thereafter, the spectral spectrum at a wavelength of 300 to 800 nm was measured using an ultraviolet visible spectrophotometer (trade name: U-Best V-570, manufactured by Nippon Bunko K.K.), and the ultraviolet transmittance of this layered product Quot; barrier property &quot;) was measured. ? "(Good) when the ultraviolet transmittance at wavelengths of 380 nm or less was 5% or less and" x "(bad) when the ultraviolet transmittance was 5% or less.

(evaluation)

The pressure-sensitive adhesive compositions of Examples 1 to 27 exhibited good adhesiveness through unshallow life and excellent handling, coatability, gel content, adhesive property, optical properties, and full residue (releasability) without laminating under air Respectively. The pressure-sensitive adhesive composition of Example 27 also showed good UV-blocking properties.

Among these pressure-sensitive adhesive compositions, the weight average molecular weight of the A component is 400,000 to 600,000, the content of the A component is 90 to 99.5 parts by mass, the content of the B component is 0.5 to 10 parts by mass, the content of the C component is 0.05 to 0.5 parts by mass Sensitive adhesive compositions of Examples 3, 4, 6, 8, 9, and 10 satisfying the above-mentioned ranges are excellent in curability under air, initial adhesive strength of about 15 N / 25 mm, adhesive strength under heat- Respectively.

In the pressure-sensitive adhesive composition containing the component E, the weight average molecular weight of the component A is 400,000 to 600,000, the content of the component A is 90 to 99.5 parts by mass, the amount of the (meth) acryloyl functional group is 0.6 to 10.6 mmol / 13, 14, 16, 17, 23, 25 and 26 using E-1 component and / or E-2 component as E component were used in amounts of 5 to 10 g / 15 N / 25 mm and showed good adhesion and optical properties under heat and moisture and heat.

In particular, the pressure-sensitive adhesive compositions of Examples 4, 8, 13, 14, 16, 21, 23, and 25 exhibit excellent adhesive properties including low adhesive strength of about 5 to 15 N / 25 mm, The results were very good throughout the evaluation items.

The addition of the component B makes it possible to use an acylphosphine oxide initiator under air and reduce the amount of the acylphosphine oxide initiator used. The pressure-sensitive adhesive compositions of Examples 3 to 5, 7 to 10, 12 to 14, 16 to 18, 20 to 21 and 23 to 27 in which an acylphosphine oxide-based initiator was used and the amount thereof used was reduced, The value of the initial color difference can be suppressed to a low level and the color difference value after the durability shows an equivalent value without substantially changing from the initial value.

On the other hand, in the pressure-sensitive adhesive composition of Comparative Example 1, the molecular weight of component A was too large, and viscosity and viscosity were high, resulting in poor coating properties. In Comparative Example 2, since the molecular weight of the component A was too small, the gel content was small (that is, the film strength after the ultraviolet curing was poor) and the residual paste (re-peelability) was poor.

In the pressure-sensitive adhesive compositions of Comparative Examples 3 to 6, since the content of the component B or the component C deviated from the range of the present invention, the pressure-sensitive adhesive composition showed poor adhesive properties and optical characteristics when cured under air. In addition, since the pressure-sensitive adhesive compositions of Comparative Examples 7 to 10 used a photopolymerization initiator other than acylphosphine oxide as the component C, the optical characteristics were poor.

In the pressure-sensitive adhesive compositions of Comparative Examples 11 to 14, the content of the (meth) acryloyl functional group of component A deviated from the range of the present invention, resulting in poor adhesive properties, optical characteristics, and gel content (film strength).

In the pressure-sensitive adhesive compositions of Comparative Examples 15 to 17, the content of the component D deviated from the range of the present invention, resulting in poor adhesive properties. Further, from the comparison of the pressure-sensitive adhesive compositions of Comparative Examples 13 to 14, it was found that when the A component and the D component having a (meth) acryloyl group-containing functional group were not used in combination, the adhesive holding force under poor wet heat conditions was poor.

In the pressure-sensitive adhesive compositions of Comparative Examples 18 to 19, since the component D was a silane coupling agent having no epoxy functional group, the adhesive property was poor. In addition, the pressure-sensitive adhesive composition of Comparative Example 20 had a poor adhesive property because the content of the E component deviated from the range of the present invention.

In the pressure-sensitive adhesive compositions of Comparative Examples 21-1 and 21-2, an acrylic acid ester monomer was used as the component E, and the amount of the acrylic acid ester monomer deviated from the range of the present invention, resulting in poor coatability and optical characteristics.

Since the pressure-sensitive adhesive composition of Comparative Example 22-2 was made of a thermosetting agent and was made into oily product, the pressure-sensitive adhesive property was poor. Since the pressure-sensitive adhesive composition of Comparative Example 22-1 was cured under the protection of a laminate using a heat-crosslinking agent, the pressure-sensitive adhesive properties and optical characteristics were comparatively good. However, since the weight average molecular weight of the component A is large, handling and coating properties are poor. In addition, when the pressure-sensitive adhesive composition of Comparative Example 22-3 had the same composition as that of Comparative Examples 22-1 and 22-2, and the heat crosslinking agent was not blended, the pressure-sensitive adhesive properties and optical properties were poor.

In addition, the pressure-sensitive adhesive composition of Comparative Example 23-2 used a heat-crosslinking agent and good adhesive property, but required curing at 40 占 폚 for 4 days. That is, when the above curing was not carried out, both the adhesive property and the optical property were poor as shown in Comparative Example 23-1.

The ultraviolet curing pressure-sensitive adhesive composition of the present invention is preferably used in applications such as electronic materials, optical materials and the like, particularly in the application of a functional film such as an antireflection film to a surface of a plasma display (PDP) or a liquid crystal display .

Claims (7)

(Component B), a photopolymerization initiator (component C), a silane coupling agent (component D), and a mixture of the component (A) and the component (A) and / or the polymerizable unsaturated group (E component) having a polymerizable unsaturated group other than the component B as a constituent component,
The component (A) has a repeating unit derived from a (meth) acrylic monomer in the main chain and has a (meth) acryloyl group in the side chain and a (meth) acryloyl group in the side chain. (Meth) acryl-based polymer having a glass transition temperature (Tg) of from -55 ° C to 0 ° C and a weight average molecular weight (Mw) in a range of from 200,000 to 1,000,000,
The component C is an acylphosphine oxide photopolymerization initiator,
The component D is a silane coupling agent having an epoxy functional group,
Wherein the amount of the component A is from 80 to 99.5 parts by mass, the content of the component B is from 0.5 to 20 parts by mass, the content of the component C is from 0.05 to 3 parts by mass, the content of the component D 0.1 to 5 parts by mass of the component (E), and 0 to 20 parts by mass of the component (E). The composition according to claim 1, wherein the component A has an alkoxysilyl-based functional group having an alkoxysilyl skeleton in the side chain, and a crosslinkable (meth) acryl-based polymer containing 0.04 to 4 mmol of the alkoxysilyl- Curable pressure sensitive adhesive composition. The polyimide resin composition according to claim 1 or 2, wherein the E component is a polyfunctional oligomer having at least two (meth) acryloyl group-containing functional groups per molecule,
Wherein the E component is contained in an amount of 0.5 to 20 parts by mass when the total amount of the A component and the B component is 100 parts by mass. The ultraviolet curable pressure-sensitive adhesive composition according to claim 3, wherein the E component is a polyfunctional oligomer having an aliphatic polyester as a basic skeleton and a weight average molecular weight (Mw) in a range of 1,000 to 10,000. The ultraviolet curable pressure-sensitive adhesive composition according to claim 3, wherein the E component is a polyfunctional oligomer having a basic skeleton of a bisphenol type epoxy resin and a weight average molecular weight (Mw) in a range of 400 to 2000. The ultraviolet curable pressure-sensitive adhesive composition according to any one of claims 1 to 3, which contains, as an ultraviolet absorber (component F), a benzophenone compound having a lambda _max in a wavelength range of 350 to 400 nm. The ultraviolet curable pressure-sensitive adhesive composition according to claim 1 or 2, wherein the component C is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.