JP2019206601A - Adhesive film, and curable composition - Google Patents

Abstract

To provide an adhesive film having an adhesive layer hard to generate resin off-scourings at processing while having appropriate weak adherence.SOLUTION: There is disclosed an adhesive film 1 provided with an adhesive layer 12 including a cured product of a curable composition containing a radical polymerizable constituent. The radical polymerizable constituent includes 2 functional urethane acrylate (A1), a nitrogen-containing monofunctional acrylic monomer (A2), and an oxyalkylene group-containing acrylic monomer (A3).SELECTED DRAWING: Figure 1

Description

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

  In a manufacturing process of an image display device such as a liquid crystal display device or an organic EL display (OLED), a surface protective film may be provided on the substrate in order to improve manufacturing efficiency and suppress the occurrence of dents or scratches (for example, Patent Document 1). This surface protective film is generally finally peeled off from the substrate after the necessary steps. In order to reduce the load on the member on the substrate, the surface protective film needs to have a slight adhesiveness that enables peeling with a very small force. An acrylic pressure-sensitive adhesive or the like is used as a pressure-sensitive adhesive that forms a pressure-sensitive adhesive layer.

JP2015-218296A

  However, the conventional pressure-sensitive adhesive layer containing an acrylic pressure-sensitive adhesive or the like and having slight adhesiveness has a problem that it is easy to generate resin scraps during processing such as cutting and excavation. In particular, in the manufacture of display devices such as liquid crystal display devices and OLEDs, even if a small amount of foreign matter such as resin waste adheres to the substrate, it may cause a fatal defect. is important. For example, a thin film transistor mounted on a glass substrate of a liquid crystal display device is extremely vulnerable to foreign matter contamination, and even a foreign matter of about several angstroms can cause a defect such as a dark spot on a display.

  On the other hand, although a hard resin layer such as a hard coat layer hardly generates resin waste, it does not have adhesiveness, so that it is difficult to apply as a surface protective film temporarily provided during the manufacturing process. That is, it has been difficult to sufficiently suppress the generation of resin waste while maintaining fine adhesiveness that can ensure appropriate sticking properties and peelability.

  Therefore, a main object of the present invention is to provide an adhesive film having an adhesive layer that has an appropriate fine adhesive property and hardly generates resin waste during processing.

One aspect of the present invention provides an adhesive film comprising an adhesive layer containing a cured product of a curable composition containing a radically polymerizable component. The radical polymerizable component is
(A1) a bifunctional urethane acrylate having two (meth) acryloyl groups;
(A2) It has one (meth) acryloyl group and a nitrogen-containing group, and the nitrogen-containing group is represented by the following formula (1a) or (1b):

In the formulas (1a) and (1b), R ¹ and R ² are each independently a monovalent atom composed of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom. A nitrogen-containing monofunctional acrylic monomer, wherein R ³ and R ⁴ each independently represents a divalent group consisting of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom;
including.

  The curable composition is a compound other than (A3) a bifunctional urethane acrylate and a nitrogen-containing monofunctional acrylic monomer, and includes an oxyalkylene group-containing acrylic monomer having one or more (meth) acryloyl groups and oxyalkylene groups. You may go out. Alternatively, at least one of bifunctional urethane acrylate and nitrogen-containing monofunctional acrylic monomer may contain a compound having an oxyalkylene group.

  When the curable composition contains an oxyalkylene group-containing acrylic monomer as a compound other than the bifunctional urethane acrylate and the nitrogen-containing monofunctional acrylic monomer, at least one of the bifunctional urethane acrylate and the nitrogen-containing monofunctional acrylic monomer is A compound having an oxyalkylene group (oxyalkylene group-containing acrylic monomer) may or may not be contained. When at least one of the bifunctional urethane acrylate and the nitrogen-containing monofunctional acrylic monomer contains a compound having an oxyalkylene group (oxyalkylene group-containing acrylic monomer), the curable composition has a bifunctional urethane acrylate and a nitrogen-containing monofunctional As a compound other than the acrylic monomer, an oxyalkylene group-containing acrylic monomer may or may not be contained.

  The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film according to one aspect of the present invention is less likely to generate resin waste during processing while having appropriate fine adhesion.

  The radically polymerizable component may further contain (A4) a polyfunctional acrylic monomer having 3 or more (meth) acryloyl groups. In this case, the oxyalkylene group-containing monomer may be a compound other than a bifunctional urethane acrylate, a nitrogen-containing monofunctional acrylic monomer and a polyfunctional acrylic monomer, or a bifunctional urethane acrylate, a nitrogen-containing monofunctional acrylic monomer or a polyfunctional At least one of the acrylic monomers may include a compound having an oxyalkylene group.

  When the curable composition contains an oxyalkylene group-containing acrylic monomer as a compound other than the bifunctional urethane acrylate, the nitrogen-containing monofunctional acrylic monomer and the polyfunctional acrylic monomer, the bifunctional urethane acrylate, the nitrogen-containing monofunctional acrylic monomer or the polyfunctional At least one of the acrylic monomers may or may not contain an oxyalkylene group-containing acrylic monomer. When at least one of bifunctional urethane acrylate, nitrogen-containing monofunctional acrylic monomer or polyfunctional acrylic monomer contains a compound having an oxyalkylene group (oxyalkylene group-containing acrylic monomer), the curable composition is a bifunctional urethane acrylate. The oxyalkylene group-containing acrylic monomer may or may not be contained as a compound other than the nitrogen-containing monofunctional acrylic monomer and the polyfunctional acrylic monomer.

  The content of the polyfunctional acrylic monomer in the curable composition may be 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the radical polymerizable component.

  The curable composition may further contain (B) a photopolymerization initiator. The curable composition may further contain (C) an antistatic agent.

  The adhesive film may further include a base film, and an adhesive layer may be provided on the base film.

  Another aspect of the present invention provides the curable composition described above. This curable composition can be used for forming an adhesive layer that has an appropriate slight adhesiveness and hardly generates resin waste during processing.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive film which has an adhesion layer which does not generate | occur | produce resin waste at the time of processing easily while having appropriate slight adhesiveness, and the curable composition which can be used in order to form this are provided. .

It is sectional drawing which shows one Embodiment of an adhesive film. It is a photograph of the adhesion layer after an excavation resistance test.

  Hereinafter, some embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In this specification, the term “(meth) acryl” means methacryl or acryl. The same applies to terms such as “(meth) acryloyl” and “(meth) acrylate”.

  FIG. 1 is a cross-sectional view showing an embodiment of an adhesive film. An adhesive film 1 shown in FIG. 1 includes a base film 11, an adhesive layer 12 provided on the main surface of the base film 11, and a separator 13 that covers a surface of the adhesive layer 12 opposite to the base film 11. With.

<Adhesive layer>
The pressure-sensitive adhesive layer 12 has slight adhesiveness that enables sticking with appropriate adhesion and subsequent peeling with a weak force. Specifically, the adhesive strength of the adhesive layer 12 to the glass plate is 0.005 N / 25 mm to 1 N / 25 mm, 0.01 N / 25 mm to 0.2 N / 25 mm, 0.01 N / 25 mm to 0.1 N / 25 mm. It may be the following. If the adhesive strength is too small, problems such as peeling during use tend to occur. If the adhesive force is excessively large, the components of the adhesive layer may be transferred to an adherend (such as a substrate of a display device) at the time of peeling and remain as a foreign substance.

  This adhesion force is a peel test in which an adhesive layer attached to a glass plate is peeled off at a peeling angle (angle formed by the main surface of the glass plate and the direction in which the adhesive layer is pulled) 180 degrees and a peeling speed of 0.3 m / min. Means the maximum value of stress measured in As a glass plate for measuring the adhesive force, a glass plate containing silicate as a main component is used, and an adhesive layer is attached to a surface that has not been subjected to a release treatment. The pressure-sensitive adhesive layer is attached to the glass plate by applying a pressure of 5880 N / m to the pressure-sensitive adhesive layer. By applying a pressure of 5880 N / m to the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is attached to the glass plate.

  The adhesive strength measured by the above peel test may increase as the peeling speed increases, but the adhesive strength of the adhesive layer 12 is such that the peeling speed is 0.3 m / min and the peeling speed is 1.0 m. It may be within the above numerical range in both peel tests when / min. Thereby, there exists a tendency which can avoid problems, such as generation | occurrence | production of the foreign material resulting from excessive adhesive force, and damage to a member more effectively.

  The thickness of the adhesive layer 12 is not particularly limited, but may be 5 μm or more and 200 μm or less, 10 μm or more and 150 μm or less, and 50 μm or more and 100 μm or less. When the thickness of the pressure-sensitive adhesive layer is within these ranges, it is possible to achieve both higher level of adhesion and suppression of generation of resin waste. If the pressure-sensitive adhesive layer is too thick, the pressure-sensitive adhesive layer may partially remain as foreign matter on the adherend during peeling.

The fact that the adhesive layer 12 is less likely to generate resin waste during processing can be confirmed by, for example, an excavation resistance test according to the following procedures (1), (2), and (3).
(1) A distance of 20 mm is moved at a speed of 0.3 m / min while the tip of a stainless steel cylinder having a diameter of 2 mm is pressed against the surface of the adhesive layer at a 45 ° angle with a predetermined load.
(2) Then, the presence or absence of resin waste on the surface of the cured film is visually confirmed.
(3) Tests (1) and (2) are performed while increasing the load stepwise, and the maximum value of the load at which no resin debris is confirmed is recorded.

  It can be judged that the larger the maximum value of the load obtained by the excavation resistance test is, the harder the adhesive layer generates resin waste. The maximum value of the load determined by the excavation resistance test may be 300 gf or more, 400 gf or more, or 500 gf or more. The upper limit of the maximum value is not particularly limited, but is usually 5000 gf or less.

  Or the suppression effect of resin waste generation can also be simply evaluated by a method in which the corner portion of the metal scale is moved back and forth while being in contact with the adhesive layer. In this case, with respect to the adhesive layer of the adhesive film placed on the glass plate, the angle between the angle of the metal rule (for example, TZ-1341 made by KOKYUYO) held by the measurer and the surface of the adhesive layer is 45 °. Make contact. In this state, the metal scale is slid forward as viewed from the measurer while pressing against the adhesive layer with a load of 300 gf / cm 2. Thereafter, the surface of the pressure-sensitive adhesive layer is visually observed, and the presence or absence of resin waste generated by scraping the pressure-sensitive adhesive layer is confirmed.

The adhesive layer 12 may have antistatic properties. When the adhesive layer 12 has antistatic properties, there is a tendency that adhesion of foreign matter in the air and generation of static electricity can be suppressed. Antistatic properties are particularly important when an adhesive film is used to produce an image display device such as an OLED. The antistatic property of the adhesive layer 12 can be evaluated based on its surface resistivity. The surface resistivity of the adhesive layer 12 may be 1 × 10 ¹² Ω / □ or less, 1 × 10 ¹¹ Ω / □ or less, or 1 × 10 ¹⁰ Ω / □ or less. The surface resistivity in the present specification is a value measured when a voltage of 100 V is applied for 10 seconds to a test piece left for 1 hour in an environment of a temperature of 23 ° C. and a humidity of 55%.

  The adhesive layer 12 may be transparent. Specifically, the haze of the adhesive layer 12 may be 1% or less. The haze can be measured using a haze meter or the like.

  The adhesive layer 12 can be a film containing a cured product of a curable composition containing a radical polymerizable component as described below. In other words, the pressure-sensitive adhesive layer 12 can be a cured film formed by curing a film of the curable composition.

  Hereinafter, the curable composition which can be used in order to form the adhesion layer 12 is demonstrated. The curable composition which concerns on one Embodiment contains (A1) bifunctional urethane acrylate and (A2) nitrogen-containing monofunctional acrylic monomer as a radically polymerizable component. The curable composition may further contain (A3) an oxyalkylene group-containing acrylic monomer and / or (A4) a polyfunctional acrylic monomer. A curable composition hardens | cures because a crosslinked polymer produces | generates by radical polymerization of a radically polymerizable component.

The curable composition according to one embodiment contains (A3) an oxyalkylene group-containing acrylic monomer, (A1) a bifunctional urethane acrylate, (A2) a nitrogen-containing monofunctional acrylic monomer, and (A4) a polyfunctional acrylic monomer. Any one selected from includes a compound having an oxyalkylene group, or both of them contain a crosslinked polymer containing an oxyalkylene group (or polyoxyalkylene group) in the main chain and / or side chain An adhesive layer (cured film) can be formed. It is considered that the (poly) oxyalkylene group in the crosslinked polymer mainly contributes to the expression of slight tackiness. The (poly) oxyalkylene group also tends to improve the antistatic property of the adhesive layer.
Details of each component will be described below.

(A1) Bifunctional urethane acrylate The bifunctional urethane acrylate has two (meth) acryloyloxy groups (CHR = C (= O) O-, R is a hydrogen atom or a methyl group) and a urethane group (-NHC (= O ) O-) urethane acrylate. The bifunctional urethane acrylate generally has a polyurethane chain which is a polycondensation reaction product of a diol and a diisocyanate, and (meth) acryloyl groups bonded to both ends of the polyurethane chain. It is thought that bifunctional urethane acrylate mainly contributes to suppression of resin waste generation.

  This bifunctional urethane acrylate, for example, generates a polycondensation reaction product which is a polyurethane chain having an isocyanate group at the terminal by the reaction of a diol and a diisocyanate; And producing a bifunctional urethane acrylate by reaction with a monofunctional acrylic monomer having a

  Examples of the diol that can be used as a raw material for the bifunctional urethane acrylate include polycarbonate diol, polyester diol, polyether diol, and polycaprolactone diol. These compounds may be used alone or in combination of two or more. In general, urethane acrylates obtained using polycarbonate diol, polyester diol, polyether diol, or polycaprolactone diol may be referred to as polyether urethane acrylate, polycarbonate urethane acrylate, polyester urethane acrylate, or caprolactone urethane acrylate, respectively. is there.

  Diisocyanates that can be used as raw materials for bifunctional urethane acrylates include tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylylene diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate. , Hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, m-phenylene diisocyanate, biphenylene diisocyanate, tetramethylene diisocyanate and hexamethylene diisocyanate. These compounds may be used alone or in combination of two or more.

  The monofunctional acrylic monomer having a hydroxyl group that can be used as a raw material for the bifunctional urethane acrylate includes 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2- Examples include hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 1,4-cyclohexanedimethanol mono (meth) acrylate. These compounds may be used alone or in combination of two or more.

  The bifunctional urethane acrylate may further have an oxyalkylene group. The bifunctional urethane acrylate having an oxyalkylene group can be obtained, for example, by a method using a diol having an oxyalkylene group (for example, a polyether polyol). The oxyalkylene group in the bifunctional urethane acrylate can be a divalent group represented by the following formula (3).

  The weight average molecular weight of the bifunctional urethane acrylate may be 1000 or more and 20000 or less. When the weight average molecular weight of the bifunctional urethane acrylate is within this range, both fine adhesion and suppression of resin waste can be achieved at a higher level. For the same reason, the weight average molecular weight of the bifunctional urethane acrylate may be 1500 or more and 20000 or less, or 2000 or more and 17000 or less. When the weight average molecular weight of the bifunctional urethane acrylate is less than 1000, the adhesive force tends to be relatively lowered. When the weight average molecular weight is larger than 20000, the effect of suppressing resin waste generation tends to be relatively lowered. The weight average molecular weight of bifunctional urethane acrylate can be adjusted with the molar ratio of diol and diisocyanate, or those molecular weights, for example. In the present specification, the weight average molecular weight (Mw) means a value converted by a standard polystyrene calibration curve measured by a gel permeation chromatography (GPC) method.

  The content of the bifunctional urethane acrylate in the curable composition may be 10 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the radical polymerizable component. When the content of the bifunctional urethane acrylate is within this range, it is possible to achieve both higher adhesion and suppression of resin waste generation at a higher level. Further, the curable composition tends to have an appropriate viscosity that facilitates formation of the adhesive layer. From the same viewpoint, the content of the bifunctional urethane acrylate may be 30 parts by mass or more and 70 parts by mass or less, or 30 parts by mass or more and 60 parts by mass or less.

(A2) Nitrogen-containing monofunctional acrylic monomer The nitrogen-containing monofunctional acrylic monomer has one (meth) acryloyl group (CHR = C (= O)-) and a nitrogen-containing group. The nitrogen-containing monofunctional acrylic monomer may further have an oxyalkylene group. The oxyalkylene group in the nitrogen-containing monofunctional acrylic monomer can be a divalent group represented by the following formula (3). The nitrogen-containing group is represented by the following formula (1a) or (1b):

It is group represented by these. In formula (1a) and formula (1b), R ¹ and R ² each independently represents a monovalent group comprising at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom, and R ³ and R ⁴ independently represents a divalent group comprising at least one kind of atom selected from a carbon atom, a hydrogen atom and an oxygen atom.

R ¹ and R ² may each independently be an alkyl group having 1 to 3 carbon atoms which may have a substituent, or a hydrogen atom, particularly a methyl group, an ethyl group, an isopropyl group or hydroxyethyl. It may be a group. R ¹ and R ² may each independently be a hydrogen atom or a methyl group from the viewpoint of achieving both high tackiness and suppression of resin waste generation at a higher level. For the same reason, R ³ , R ⁴ and the nitrogen atom (N) may form a tetrahydro-1,4-oxazine ring.

The nitrogen-containing monofunctional acrylic monomer may be a monofunctional (meth) acrylamide derivative represented by the following formula (2a) or (2b). In formulas (2a) and (2b), R ¹ , R ² , R ³ and R ⁴ have the same meanings as described above, and R represents a hydrogen atom or a methyl group.

  From the viewpoint of suppressing resin waste generation, the theoretical Tg of a homopolymer formed from a nitrogen-containing monofunctional acrylic monomer may be 100 ° C. or higher. Specific examples of the nitrogen-containing monofunctional acrylic monomer include acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropylacrylamide, N, N-dimethylacrylamide, (meth) acryloylmorpholine, N- Examples include isopropyl acrylamide, N, N-diethyl acrylamide, and N-hydroxyethyl acrylamide. These compounds may be used alone or in combination of two or more. From the point of compatibility with other components, N, N-dimethylacrylamide and / or (meth) acryloylmorpholine may be selected.

  The content of the nitrogen-containing monofunctional acrylic monomer in the curable composition may be 5 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the radical polymerizable component. When the content of the nitrogen-containing monofunctional acrylic monomer is within this range, both fine adhesion and suppression of resin waste can be achieved at a higher level. For the same reason, the content of the nitrogen-containing monofunctional acrylic monomer may be 15 to 50 parts by mass, or 20 to 40 parts by mass.

(A3) Oxyalkylene group-containing acrylic monomer The oxyalkylene group-containing acrylic monomer has one or more (meth) acryloyl groups and oxyalkylene groups. The curable composition may contain one or more oxyalkylene group-containing acrylic monomers. The oxyalkylene group-containing acrylic monomer as the component (A3) may be a compound different from (A1) a bifunctional urethane acrylate, (A2) a nitrogen-containing monofunctional acrylic monomer, and (A4) a polyfunctional acrylic monomer.

  Two or more oxyalkylene groups may be linked to form a polyoxyalkylene group. The oxyalkylene group and the polyoxyalkylene group can be, for example, a divalent (poly) oxyethylene group and / or a (poly) oxypropylene group represented by the following formula (3). Acrylic monomers having (poly) oxyethylene groups and / or (poly) oxypropylene groups tend to have good compatibility with other components. In particular, according to the acrylic monomer having a (poly) oxyethylene group, an even more excellent effect can be obtained in terms of slight tackiness.

  In formula (3), d represents 2 or 3, and e represents an integer of 1 to 100. e may be 50 or less, 20 or less, or 10 or less, or 2 or more, or 5 or more. When the repeating number e of the oxyethylene group or oxypropylene group is in this range, particularly excellent fine tackiness is easily obtained.

  The content of the oxyalkylene group-containing acrylic monomer in the curable composition may be 1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the radical polymerizable component. When the content of the oxyalkylene group-containing acrylic monomer is within this range, a more excellent effect can be obtained in terms of slight tackiness. Moreover, it is advantageous also in terms of antistatic properties and compatibility with other components. For the same reason, the content of the oxyalkylene group-containing monomer may be 3 to 40 parts by mass, or 5 to 30 parts by mass.

(A4) Polyfunctional acrylic monomer The polyfunctional acrylic monomer has three or more (meth) acryloyl groups. The polyfunctional acrylic monomer is considered to contribute mainly to suppression of resin waste generation. In the present specification, a compound having three or more (meth) acryloyl groups and a urethane group is classified as a polyfunctional acrylic monomer.

The double bond equivalent of the polyfunctional acrylic monomer may be 250 or less. Thereby, the especially outstanding effect is acquired at the point of suppression of resin waste generation | occurrence | production. For the same reason, the double bond equivalent of the polyfunctional acrylic monomer may be 200 or less, or 150 or less. In the present specification, the double bond equivalent is represented by the formula:
Double bond equivalent = mean value calculated by the molecular weight / number of double bonds in the same molecule. When the polyfunctional acrylic monomer is a mixture of compounds having different molecular weights, the average value of double bond equivalents may be obtained using the weight average molecular weight value as the molecular weight. The average value of double bond equivalents may be within the above numerical range.

  Specific examples of polyfunctional acrylic monomers include trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, glycerol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate , Dipentaerythritol hexa (meth) acrylate, tris (acryloxyethyl) isocyanurate, tris (methacryloxyethyl) isocyanurate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, ditrimethylolpropane tetraacrylate Dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Examples include pentaerythritol penta (meth) acrylate, polyglycerin polyacrylate, alkylene oxide modified polyfunctional (meth) acrylate obtained by modifying these with ethylene oxide or propylene oxide, and caprolactone modified polyfunctional (meth) acrylate obtained by modifying these with caprolactone. It is done. These compounds may be used alone or in combination of two or more.

  The polyfunctional acrylic monomer may further have an oxyalkylene group. The oxyalkylene group in the polyfunctional acrylic monomer can be a divalent group represented by the above formula (3). For example, the alkylene oxide-modified polyfunctional (meth) acrylate has an oxyoxyalkylene group, which can be selected from the viewpoint of slightly tackiness and compatibility.

  The content of the polyfunctional acrylic monomer in the curable composition may be 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the radical polymerizable component. When the content of the polyfunctional acrylic monomer is within this range, both fine adhesion and suppression of resin waste can be achieved at a higher level. For the same reason, the content of the polyfunctional acrylic monomer may be 3 parts by mass or more and 20 parts by mass or less, or 5 parts by mass or more and 15 parts by mass or less.

  The radically polymerizable component may contain a radically polymerizable compound other than (A1), (A2), (A3) and (A4) described above. However, the total content of the components (A1), (A2), (A3), and (A4) is 16.5 parts by mass or more, 50 parts by mass or more with respect to 100 parts by mass of the radical polymerizable component, It may be 60 parts by mass or more, 80 parts by mass or more, 90 parts by mass or more, or 100 parts by mass or less.

  The oxyalkylene group contained in the curable composition may be derived from any of (A1), (A2), (A3) and (A4), but from the viewpoint of appropriate slight tackiness, The total content of alkylene groups is 1 part by mass or more and 60 parts by mass or less, 3 parts by mass or more and 40 parts by mass or less, or 5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the curable composition. Also good.

  The total content of the radically polymerizable components in the curable composition is not particularly limited, but may be 70% by mass or more, 80% by mass or more, or 90% by mass or more.

(B) Photopolymerization initiator The curable composition may further contain a photopolymerization initiator for efficient curing by photoradical polymerization. The photopolymerization initiator is not particularly limited as long as it is a compound that initiates radical polymerization by irradiation with active energy rays. The active energy rays include ultraviolet rays, electron beams, α rays, β rays, and γ rays. As the photopolymerization initiator, benzophenone series, anthraquinone series, benzoyl series, sulfonium salts, diazonium salts, onium salts, acylphosphine oxides, and the like can be used. The photopolymerization initiator may be an intramolecular hydrogen abstraction type photopolymerization initiator.

  Specific examples of the photopolymerization initiator include benzophenone, 4-methylbenzophenone, N, N, N ′, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N-tetraethyl-4,4. '-Diaminobenzophenone, 4-methoxy-4'-dimethylaminobenzophenone, α-hydroxyisobutylphenone, 2-ethylanthraquinone, t-butylanthraquinone, 1,4-dimethylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone 3-chloro-2-methylanthraquinone, 1,2-benzoanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexylphenyl , Aromatic ketone compounds such as 2,2-dimethoxy-1,2-diphenylethane-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzoin, methylbenzoin, ethylbenzoin, etc. Benzoin ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, and benzoin phenyl ether; benzyl, 2,2-diethoxyacetophenone, benzyldimethyl ketal, β- (acridin-9-yl) (meta ) Ester compound of acrylic acid; 9-phenylacridine, 9-pyridylacridine, acridine compounds such as 1,7-diacridinoheptane, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (O-Chloroph Nyl) -4,5-di (m-methoxyphenyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5 -Diphenylimidazole dimer, 2- (p-methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) 5-phenylimidazole dimer, 2- (2, 2,4,5-triarylimidazole dimers such as 4-dimethoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer, 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -1-butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-mol Rino-1-propane, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) It is done. These compounds may be used alone or in combination of two or more.

  Content of the photoinitiator in a curable composition is 0.01 mass part or more and 10 mass parts or less, 0.1 mass part or more and 6 mass parts or less with respect to 100 mass parts of radically polymerizable components, or 0.00. 5 mass parts or more and 5 mass parts or less may be sufficient. When the content of the photopolymerizable compound is within this range, particularly good photopolymerizability can be obtained.

(C) Antistatic agent The curable composition may further contain an antistatic agent. Since the radically polymerizable component composed of the above-described components has good compatibility with the antistatic agent, it is easy to impart an antistatic function to the adhesive layer. When the adhesive film is used for the production of an image display device, it is effective in preventing various defects caused by static electricity that the curable composition and the adhesive layer formed therefrom contain an antistatic agent. is there. For example, most of the manufacturing process of a liquid crystal display device is performed on a glass substrate. However, since the glass substrate is a nonconductor, electric charges generated instantaneously are difficult to be dispersed below the substrate. Therefore, various members such as an insulating film and a thin film transistor formed on the glass substrate can be damaged by static electricity.

  The antistatic agent is not particularly limited as long as it reduces the surface resistivity of the adhesive layer. The antistatic agent can be, for example, an ionic substance selected from an alkali metal salt, an alkaline earth metal salt, and an ionic liquid.

  Examples of alkali metal salts include cations of alkali metals such as lithium, sodium, potassium, and anions such as perchloric acid, hexafluorophosphoric acid, tetrafluoroboric acid, trifluoromethanesulfonic acid, and organic boron. Salt. Examples of the alkaline earth metal salt include a salt containing an alkaline earth metal cation such as magnesium and the anion. From the viewpoint of ion dissociation property, lithium perchlorate or lithium trifluoromethanesulfonate may be selected. Commercially available alkali metal salts include PEL-100 (10 parts by weight of lithium perchlorate manufactured by Nippon Carlit Co., Ltd., 90 parts by weight of polyoxypropylene glycol), PEL-25 (lithium trifluoromethanesulfonate manufactured by Nippon Carlit Co., Ltd. 5) Parts by weight, lithium perchlorate 10 parts by weight, and polyoxyethylene glycol-polyoxypropylene glycol copolymer 85 parts by weight).

  The antistatic agent may be a cationic antistatic agent, an anionic antistatic agent, an amphoteric antistatic agent, a nonionic antistatic agent, or an ionic conductivity imparting agent. It has a cationic group such as a quaternary ammonium salt, a pyridinium salt, or a primary to tertiary amino group. An anionic antistatic agent has anionic groups, such as a sulfonate group, a sulfate ester base, a phosphate ester base, a sulfonate group, for example. Examples of amphoteric antistatic agents include amino acid-based and aminosulfate-based antistatic agents. Nonionic antistatic agents include antistatic agents such as amino alcohol, glycerin, and polyethylene glycol. Examples of the ion conductivity-imparting agent include a composite of a matrix polymer such as polyethylene oxide, polyphenylene oxide or a copolymer thereof and an alkali metal salt such as sodium or lithium. These can also combine 2 or more types.

  The content of the antistatic agent in the curable composition is 0.01 parts by mass or more and 30 parts by mass or less, 0.1 parts by mass or more and 20 parts by mass or less, or 0.1 parts by mass with respect to 100 parts by mass of the radical polymerizable component. It may be not less than 10 parts by mass and not more than 10 parts by mass. When the content of the antistatic agent is within this range, particularly good surface resistivity can be obtained.

(Other)
The curable composition may further contain other components without departing from the gist of the present invention. Examples of other components include additives such as antifouling agents, flame retardants, antioxidants, dispersants, ultraviolet absorbers, pigments, plasticizers, surfactants, and thixotropic agents. These additives may be used alone or in combination of two or more. The curable composition may contain a thermal radical polymerization initiator together with the photopolymerization initiator or in place of the photopolymerization initiator.

  The viscosity at 25 ° C. of the curable composition may be 300 mPa · s or more and 10,000 mPa · s or less. When the viscosity at 25 ° C. of the curable composition is within this range, a more excellent effect can be obtained in terms of coatability. When the coatability is excellent, a thick adhesive layer is easily formed. For the same reason, the viscosity of the curable composition at 25 ° C. may be 500 mPa · s or more and 5000 mPa · s or less, or 1000 mPa · s or more and 3000 mPa · s or less.

  The curable composition for coating may or may not contain an organic solvent, but the curable composition according to this embodiment can be applied without requiring an organic solvent. It can have a suitable viscosity. Solvent-free is advantageous in terms of environmental friendliness and process shortening.

<Base film>
The base film 11 includes a plastic film 20 and an antistatic layer 30 formed on one side of the plastic film 20.

  The plastic film 20 may be a transparent plastic film. Although a base film is not restricted to what has a plastic film, a plastic film is especially advantageous at the point of the coating property of a curable composition, and the smoothness of an adhesion layer. The plastic film 20 may be a stretched plastic film. Thereby, the more superior effect is acquired at the point of the winding property of a film, and workability.

  Specific examples of the plastic film 20 include polyethylene terephthalate (PET), triacetyl cellulose (TAC), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate (PC), polyimide (PI), polyethylene (PE). , Polypropylene (PP), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), cycloolefin copolymer (COC), cycloolefin polymer (COP), norbornene resin, polyethersulfone, cellophane, aromatic polyamide, or combinations thereof The film containing is mentioned. The plastic film 20 may be a polyethylene, polypropylene, polyethylene terephthalate, polymethacrylate, polycarbonate, or polyvinyl chloride film.

  The thickness of the plastic film 20 or the base film 11 is not particularly limited, but may be 10 μm or more, 20 μm or more, 25 μm or more, 30 μm or more, or 40 μm or more, and is 200 μm or less, 150 μm or less, 125 μm or less, or 100 μm or less. There may be. When the thickness of the base film 11 is within this range, a more excellent effect can be obtained in terms of film winding property and workability. If the plastic film is thin, the strength tends to be insufficient. If the plastic film is thick, the flexibility tends to decrease. If the plastic film has low flexibility, the base film tends to be difficult to follow the complex shape of the adherend, and as a result, the adhesive film may partially peel from the adherend during the process. is there.

  In the pressure-sensitive adhesive film of FIG. 1, the antistatic layer 30 is provided on the surface of the plastic film 20 opposite to the pressure-sensitive adhesive layer 12, but it is only necessary to appropriately suppress the charging of the pressure-sensitive adhesive film. The position is not particularly limited. For example, an antistatic layer may be provided on both surfaces of the plastic film 20. Moreover, the separator 13 may have an antistatic layer on one side or both sides. The antistatic layer may not be provided.

The antistatic layer 30 usually has a low surface efficiency of 1 × 10 ¹¹ Ω / □ or less. The antistatic layer 30 is, for example, an ion selected from an ionic surfactant, an alkali metal salt, an alkaline earth metal salt, a metal fine particle, a nonmetal conductive fine particle (such as carbon nanotube), a conductive polymer, and an ionic liquid. A film containing an antistatic agent such as a conductive material or a conductive material as a main component can be used. The content of the antistatic agent in the antistatic layer may be 50 parts by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the antistatic layer. The thickness of the antistatic layer 30 is not particularly limited, but may be, for example, 0.01 μm or more and 100 μm or less.

  The surface of the base film 11 on the adhesive layer 12 side may be subjected to antistatic treatment, corona treatment, plasma treatment, and adhesion imparting primer treatment.

<Separator>
The separator 13 is not particularly limited, but can be a plastic film including any resin such as a polyester resin, an olefin resin, or an acrylic resin. The separator 13 may have a plastic film and an antistatic layer provided on one side or both sides thereof. The antistatic layer in this case can have the same configuration as the antistatic layer 30 of the base film 11. One or both surfaces of the separator 13 may be subjected to a mold release process, an adhesion imparting process, or an antistatic process.

  The thickness of the separator 13 is not particularly limited, but may be 10 μm or more and 300 μm or less.

  When the adhesive film 1 is used, the base film 11 or the separator 13 can be peeled off and the exposed adhesive layer 12 can be attached to a desired site.

  The pressure-sensitive adhesive film 1 includes, for example, a step of forming a film of the curable composition on the base film 11 and a pressure-sensitive adhesive layer containing a cured product of the curable composition by curing the curable composition by active energy rays or the like. Can be manufactured by a method including a step of forming the film.

  As a method for forming a film of the curable composition, a normal coating method or printing method can be applied. Specifically, for example, reverse coating, transfer roll coating, gravure roll coating, kiss coating, cast coating, spray coating, spin coating, dip coating, slot orifice coating, air doctor coating, bar coating, comma coating, blade coating, Printing including dam coating and die coating, intaglio printing such as gravure printing, and stencil printing such as screen printing can be used. If necessary, the viscosity of the curable composition can be adjusted by a method such as blending of a low-viscosity radical polymerization component and addition of a solvent.

  As an active energy ray for curing the curable composition, an ultraviolet ray, an electron beam or the like can be used. Irradiation with active energy rays can also be performed in a nitrogen atmosphere. Thereby, there exists a tendency for the sclerosis | hardenability of a curable composition to improve. For the same purpose, after the separator 13 is laminated on the film of the uncured curable composition, the active energy ray may be irradiated there. When the curable composition contains a thermal radical polymerization initiator, the curable composition may be cured by heating. Prior to curing, the solvent is removed from the film if necessary.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

1. Raw materials Table 1 shows the raw materials used to prepare the curable compositions. Antistatic agent PEL-25 is a mixture of 5 parts by mass of lithium trifluoromethanesulfonate, 10 parts by mass of lithium perchlorate, and 85 parts by mass of a polyoxyethylene glycol-polyoxypropylene glycol copolymer.

The double bond equivalent of the bifunctional urethane acrylate and the polyfunctional acrylic monomer shown in the table was calculated based on the following formula.
Double bond equivalent = weight average molecular weight (measured or manufacturer reported value) / number of polymerizable double bonds in the same molecule

(A1-3) The weight average molecular weights of the hyaloid 4864HMG (bifunctional urethane acrylate) and the acrylic resin are values obtained by conversion using a standard polystyrene calibration curve measured by a gel permeation chromatography (GPC) method. The measurement conditions of the GPC method are as follows.
・ Equipment: HLC-8320GPC (built-in RI detector) manufactured by Tosoh Corporation
・ Detector: RI (differential refractometer)
・ Solvent: Pure grade 1 THF (tetrahydrofuran)
Guard column: TSK-guardcolumn SuperMP (HZ) -H (1)
Guard column size: 4.6 mm (ID) x 20 mm
Column: Tosoh Corporation TSK-GELSuperMultipore HZ-H (3 connected), column size: 4.6 mm (ID) x 150 mm
・ Temperature: 40 ℃
Sample concentration: 0.01g / 5mL
・ Injection volume: 10 μL
・ Flow rate: 0.35mL / min

2. Preparation of curable composition Each component was mixed in the ratio shown in Table 2, and stirred at 40 ° C for 1 hour to obtain a uniform curable composition. The numerical value in a table | surface is a mass part. The viscosity of each curable composition was measured at 25 ° C. using a digital viscometer RE80R manufactured by Toki Sangyo Co., Ltd.

3. Preparation and Evaluation of Adhesive Film Each of the obtained curable compositions was applied in an appropriate amount onto a polyethylene terephthalate (PET) film (Cosmo Shine A4300 film thickness 75 μm manufactured by Toyobo Co., Ltd.). From the top of the coating film of the curable composition, while releasing the PET film (Toray Film Processing Serapire BKE film thickness 38 μm), a 75 μm spacer is sandwiched between the PET films, and the curable composition is expanded. Pasted together. A cured film (adhesive layer) in which the curable composition was cured was formed by irradiating the coating film with an illuminance of 150 mW / cm ² and an integrated light amount of 1200 mJ / cm ² using a conveyor type metal halide lamp irradiation device. This obtained the adhesive film provided with the PET film as a base film, and the adhesion layer formed on it. The thickness of the adhesive layer was 75 μm. The following characteristics were evaluated for each obtained adhesive film. The evaluation results are shown in Table 2.

Adhesive strength The adhesive layer was made of soda-lime glass plate (manufactured by Matsunami Glass Industry Co., Ltd., large slide glass, “Water Margin t1.3” (trade name), S9213) using a rubber roll, pressure 5880 N / m, speed 2 mm / It was pasted in minutes, and left in that state at room temperature for 30 minutes. Then, the peeling test which peels off an adhesion layer from a glass plate with the peeling angle of 180 degree | times and the peeling speed of 0.3 m / min was done. The maximum value of stress per 25 mm width was recorded as the adhesive strength of the adhesive layer. Here, a laminated film having an adhesive strength of 0.005 N / 25 mm or more and 1 N / 25 mm or less is determined to be acceptable.

Excavation resistance The tip of a stainless steel cylinder having a diameter of 2 mm was moved by a distance of 20 mm at a speed of 0.3 m / min while being pressed against the surface of the adhesive layer of the laminated film at an angle of 45 ° with a predetermined load. Thereafter, the presence or absence of resin waste on the surface of the adhesive layer was visually confirmed. The test was performed while increasing the load sequentially, and the excavation resistance was determined based on the following criteria based on the maximum value of the load in which no resin debris was confirmed. Three or more are judged to be acceptable. A surface property measuring device HEIDON TYPE: 14FW manufactured by Shinto Kagaku Co., Ltd. was used as a measuring device.
1: Less than 200 gf 2: 200 gf or more and less than 300 gf 3: 300 gf or more and less than 400 gf 4: 400 gf or more and less than 500 gf 5: 500 gf or more

Surface resistivity The adhesive film was left for 1 hour in an environment of a temperature of 23 ° C. and a humidity of 55%. Next, the surface resistivity of the adhesive layer when a voltage of 100 V was applied to the adhesive layer for 10 seconds was measured.

As shown in Table 2, according to the curable composition of each example including a combination of specific radically polymerizable components, it has an appropriate slight adhesive property of 0.005 N / 25 mm or more and 1 N / 25 mm or less and is resistant to resistance. It was confirmed that an adhesive layer excellent in excavability can be formed. FIG. 2 is a photograph showing the surface of the adhesive layer of Example 7 and Comparative Example 1 after the excavation resistance test. While the adhesive layer of Comparative Example 1 generated a large amount of resin waste, no scratch was observed in the adhesive layer of Example 7. In addition, the adhesive layer of each example has excellent antistatic properties having sufficiently low surface low efficiency of 1 × 10 ¹² Ω / □ or less (in some examples, 1 × 10 ¹⁰ Ω / □ or less). It was also confirmed.

  The pressure-sensitive adhesive film according to the present invention can be applied as various pressure-sensitive adhesive films that require slight adhesiveness, such as protective films.

  DESCRIPTION OF SYMBOLS 1 ... Adhesive film, 11 ... Base film, 12 ... Adhesive layer, 13 ... Separator, 20 ... Plastic film, 30 ... Antistatic layer

Claims (14)

An adhesive film comprising an adhesive layer,
The adhesive layer contains a cured product of a curable composition containing a radical polymerizable component, and the radical polymerizable component is
(A1) a bifunctional urethane acrylate having two (meth) acryloyl groups;
(A2) It has one (meth) acryloyl group and a nitrogen-containing group, and the nitrogen-containing group is represented by the following formula (1a) or (1b):

In the formulas (1a) and (1b), R ¹ and R ² are each independently a monovalent atom composed of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom. A nitrogen-containing monofunctional acrylic monomer, wherein R ³ and R ⁴ each independently represents a divalent group consisting of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom;
(A3) A compound other than the bifunctional urethane acrylate and the nitrogen-containing monofunctional acrylic monomer, the oxyalkylene group-containing acrylic monomer having one or more (meth) acryloyl groups and oxyalkylene groups;
Including adhesive film. The radical polymerizable component is
(A4) A compound other than the oxyalkylene group-containing acrylic monomer, the polyfunctional acrylic monomer having 3 or more (meth) acryloyl groups,
The pressure-sensitive adhesive film according to claim 1, further comprising: An adhesive film comprising an adhesive layer,
The adhesive layer contains a cured product of a curable composition containing a radical polymerizable component, and the radical polymerizable component is
(A1) a bifunctional urethane acrylate having two (meth) acryloyl groups;
(A2) It has one (meth) acryloyl group and a nitrogen-containing group, and the nitrogen-containing group is represented by the following formula (1a) or (1b):

In the formulas (1a) and (1b), R ¹ and R ² are each independently a monovalent atom composed of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom. A nitrogen-containing monofunctional acrylic monomer, wherein R ³ and R ⁴ each independently represents a divalent group consisting of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom;
Including
At least one of the bifunctional urethane acrylate or the nitrogen-containing monofunctional acrylic monomer includes a compound having an oxyalkylene group,
Adhesive film. The radical polymerizable component is
(A4) a polyfunctional acrylic monomer having three or more (meth) acryloyl groups,
Further including
At least one of the bifunctional urethane acrylate, the nitrogen-containing monofunctional acrylic monomer or the polyfunctional acrylic monomer contains a compound having the oxyalkylene group,
The pressure-sensitive adhesive film according to claim 3.   The pressure-sensitive adhesive film according to claim 2 or 4, wherein a content of the polyfunctional acrylic monomer in the curable composition is 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the radical polymerizable component. .   The pressure-sensitive adhesive film according to any one of claims 1 to 5, wherein the curable composition further contains (C) an antistatic agent.   The pressure-sensitive adhesive film according to claim 1, further comprising a base film, wherein the pressure-sensitive adhesive layer is provided on the base film. A curable composition containing a radical polymerizable component,
The radical polymerizable component is
(A1) a bifunctional urethane acrylate having two (meth) acryloyl groups;
(A2) It has one (meth) acryloyl group and a nitrogen-containing group, and the nitrogen-containing group is represented by the following formula (1a) or (1b):

In the formulas (1a) and (1b), R ¹ and R ² are each independently a monovalent atom composed of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom. A nitrogen-containing monofunctional acrylic monomer, wherein R ³ and R ⁴ each independently represents a divalent group consisting of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom;
(A3) A compound other than the bifunctional urethane acrylate and the nitrogen-containing monofunctional acrylic monomer, the oxyalkylene group-containing acrylic monomer having one or more (meth) acryloyl groups and oxyalkylene groups;
A curable composition comprising: The radical polymerizable component is
(A4) A compound other than the oxyalkylene group-containing acrylic monomer, the polyfunctional acrylic monomer having 3 or more (meth) acryloyl groups,
The curable composition according to claim 8, further comprising: A curable composition containing a radical polymerizable component,
The radical polymerizable component is
(A1) a bifunctional urethane acrylate having two (meth) acryloyl groups;
(A2) It has one (meth) acryloyl group and a nitrogen-containing group, and the nitrogen-containing group is represented by the following formula (1a) or (1b):

In the formulas (1a) and (1b), R ¹ and R ² are each independently a monovalent atom composed of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom. A nitrogen-containing monofunctional acrylic monomer, wherein R ³ and R ⁴ each independently represents a divalent group consisting of at least one atom selected from a carbon atom, a hydrogen atom and an oxygen atom;
Containing
At least one of the bifunctional urethane acrylate or the nitrogen-containing monofunctional acrylic monomer includes a compound having an oxyalkylene group,
Curable composition. The radical polymerizable component is
(A4) further comprising a polyfunctional acrylic monomer having three or more (meth) acryloyl groups,
At least one of the bifunctional urethane acrylate, the nitrogen-containing monofunctional acrylic monomer or the polyfunctional acrylic monomer contains a compound having the oxyalkylene group,
The curable composition according to claim 10.   The curability according to claim 9 or 11, wherein the content of the polyfunctional acrylic monomer in the curable composition is 0.5 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the radical polymerizable component. Composition.   (B) The curable composition as described in any one of Claims 9-12 which further contains a photoinitiator.   (C) The curable composition as described in any one of Claims 9-13 which further contains an antistatic agent.