JP7073535B2 - Laminate - Google Patents

Description

The present invention relates to a laminate including a transfer layer and an adhesive layer. More specifically, the present invention relates to a laminate containing a transfer layer and an adhesive layer useful as an optical film that can be suitably used for, for example, a liquid crystal display device.

In recent years, display devices such as liquid crystal displays are rapidly becoming thinner and larger, and for the purpose of ensuring design and suppressing optical unevenness failure of display devices due to environmental changes, including optical films. The thinning of the members to be used is progressing.

For example, in a polarizing plate which is an essential member of a liquid crystal display device, when the polarizing plate expands and contracts due to a change in environmental humidity, the liquid crystal panel to which the polarizing plate is attached warps and the panel and the backlight member come into contact with each other to generate light. It is believed that unevenness will occur.

In order to solve this problem, a method using a low moisture permeability optical film (Patent Document 1), a method of suppressing a force generated by a dimensional change of the optical film (Patent Document 2 and Patent Document 3), and the like have been proposed. There is.

Further, a method (Patent Document 4) has been proposed in which a transferable optical film is used to reduce the thickness of the panel to suppress warpage of the panel.

On the other hand, for the purpose of improving the quality of the transfer layer, a method of multi-layering the non-transfer region (Patent Document 5), a transfer method of peeling the substrate after bending the transfer material in advance (Patent Document 6), and the like have been proposed. There is.

Japanese Patent Application Laid-Open No. 2015-7768 Japanese Patent Application Laid-Open No. 2014-95880 International Publication No. 2017/138551 Japanese Patent Application Laid-Open No. 2017-215562 Japanese Patent Application Laid-Open No. 2003-103997 Japanese Patent Application Laid-Open No. 10-67199

The transferable optical film disclosed in Patent Document 4 exhibits excellent effects, but in recent years, further improvement in performance has been required, and in particular, substrate peelability (transfer layer from the substrate). There is room for consideration regarding the ability to stably peel off) and the reduction of defects.

Further, in the method disclosed in Patent Document 5, when a long laminate is produced, a transport position shift or a position shift due to a dimensional change of each material in a wide laminate occurs, and the base material is peeled off. It turned out that sex may not improve. Further, it has been found that the method disclosed in Patent Document 6 may not be applicable due to structural restrictions of the production apparatus.

An object to be solved by the present invention is to provide a laminate including a transfer layer and an adhesive layer having good substrate peelability and few defects.

In order to improve the peelability of the base material, an in-plane distribution is provided in the film thickness of the transfer layer, and the film thickness of the transfer layer at the position (P1) in contact with the end of the adhesive layer is set to the inner position (P2). It has been found that the above-mentioned problems can be solved by making the film thickness thinner than that of the transfer layer in the above, and the present invention has been completed.

Therefore, the present invention, which is a specific means for solving the above problems, is as follows.

<1>
The substrate, the transfer layer, and the adhesive layer are included in this order, the transfer layer and the adhesive layer are adjacent to each other, the area of the transfer layer is wider than the area of the adhesive layer, and the film thickness of the transfer layer has an in-plane distribution. The film thickness (t1) of the transfer layer at the position (P1) where the end portion of the transfer layer is in contact with the transfer layer is thinner than the film thickness (t2) of the transfer layer at the position (P2) inside the transfer layer. Laminate.
<2>
The lamination according to <1>, wherein the difference between the adhesive force between the transfer layer and the base material (fa1) in P1 and the adhesive force (fa2) between the transfer layer and the base material in P2 is less than 3N / 25 mm. body.
<3>
The laminate according to <1> or <2>, wherein the main material of the transfer layer is a thermoplastic resin.
<4>
The laminate according to any one of <1> to <3>, wherein the laminate is a long laminate.
<5>
The laminate according to <3>, wherein the main material of the transfer layer is a vinyl aromatic resin or a cyclic olefin resin.
<6>
The laminate according to any one of <1> to <4>, wherein the main material of the transfer layer is a curable composition.
<7>
The laminate according to any one of <1> to <6>, wherein an optical film is adjacent to the surface of the adhesive layer on the side opposite to the transfer layer.
<8>
The laminate according to <7>, wherein the optical film is a polarizing film or a protective film for the polarizing film.
<9>
The laminate according to <7>, wherein the optical film is a retardation film.
<10>
A liquid crystal display device including a liquid crystal cell and the laminate according to any one of <1> to <9>.
<11>
An organic electroluminescence display device including an organic electroluminescence element and the laminate according to any one of <1> to <9>.

According to the present invention, it is possible to provide a laminate including a transfer layer and an adhesive layer having good substrate peelability and few defects.

The schematic diagram which shows the example of the laminated body of this invention and the example of the transferred body. The schematic diagram which shows the vicinity of the end part of the adhesive layer of an example of the laminated body of this invention.

The contents of the present invention will be described in detail. The description of the constituent elements described below may be based on the representative embodiments of the present invention, but the present invention is not limited to such embodiments. In the specification of the present application, "-" is used to mean that the numerical values described before and after it are included as the lower limit value and the upper limit value.

<< Transfer layer >>
The transfer layer in the present invention will be described.
In the laminated body of the present invention, the transfer layer is adjacent to the adhesive layer, and typically, the adhesive layer of the laminated body of the present invention is adhered to another article (transferred body), or the transferred body and the present. By laminating the transfer layer / base material of the present invention via an adhesive (adhesive layer) (see FIG. 1) and peeling off the base material of the laminate of the present invention, the transfer layer is peeled off from the base material and the adhesive layer. It is also transferred onto other articles.
At this time, if the force required for tearing the transfer layer is less than the force required for peeling the transfer layer from the base material, the inside of P1 is peeled between the transfer layer and the base material, and the outside of P1 is the transfer layer. Since the state remains on the substrate side, for example, the problem that the transfer layer is torn off does not occur in the subsequent process, and defects can be reduced, which is preferable.

<Film thickness>
The transfer layer of the present invention has an in-plane distribution of film thickness, and when the transfer layer and the adhesive layer are laminated, the film thickness of the transfer layer at a position (P1) where the end of the adhesive layer and the transfer layer can come into contact with each other. (T1) is characterized in that it is thinner than the film thickness (t2) of the transfer layer at the position (P2) inside it. Here, the "inner position (P2)" is typically a position where the adhesive layer and the transfer layer are in contact with each other, and represents a position closer to the center of the adhesive layer than P1 (FIGS. 1 and FIG. 2).
The substrate peelability can be improved by reducing the film thickness in the vicinity of P1 and making the transfer layer easier to tear. Specifically, the ratio of t1 to t2 (t1 / t2) is less than 1, preferably 0.9 or less, more preferably 0.8 or less, further preferably 0.7 or less, and 0.6 or less. Most preferred. By reducing t1 / t2, the frequency of tearing from an unexpected position can be reduced, the peelability of the base material can be improved, and defects in the laminated body can be reduced.

t1 is set within a range satisfying the above t1 / t2 ratio, preferably 0.05 to 7.0 μm, more preferably 0.2 to 4.5 μm, still more preferably 0.5 to 4.0 μm, and 0. Most preferably 7 to 3.5 μm. When t1 is 0.05 μm or more, the frequency of defects such as holes in the transfer layer near P1 is suppressed, which is preferable.
Further, the transfer layer in the laminated body of the present invention has a region having a film thickness of t1 (also referred to as “P1 region”; see FIG. 2) from the position P1 in contact with the end portion of the adhesive layer to the end portion of the transfer layer. It is preferable to do so. The P1 region may include a region to be transferred (a region in contact with the adhesive layer (also referred to as a “transfer region”)) and a non-transfer region as shown in FIG. 1, but the P1 region may be included in the P1 region. The transfer region of the above may be treated as a non-product portion if it does not have a film thickness for exhibiting desired performance as an optical film as a product, for example. From this point of view, the width of the region (P1 region) having a film thickness of t1 is preferably narrow from the viewpoint of increasing the profitability of the product, but the positioning accuracy when laminating the transfer layer and the adhesive layer and , It is preferable to set in consideration of dimensional changes of the transfer layer and the transferred body. For example, when the laminated body of the present invention is a long laminated body, P1 is near both ends in the width direction, and the width of t1 is usually one side in consideration of the transport position accuracy in the width direction of the web. 3 to 50 mm is preferable, 5 to 30 mm is more preferable, and 10 to 20 mm is further preferable. When the dimensional change due to the temperature and humidity of the transfer layer or the transfer layer has a significant effect on the position accuracy, it is preferable to add the width due to the dimensional change of the material to the width of t1 in consideration of the transfer position accuracy. (In this case, the additional amount of the width of t1 is preferably determined in consideration of the dimensional change rate, and the additional amount is preferably increased or decreased according to the width of the material).

The transfer layer in the laminated body of the present invention preferably has a region having a film thickness of t2 (also referred to as a “P2 region”; see FIG. 2). As shown in FIG. 1, t2 is typically the film thickness of the transfer region to be the product part, preferably satisfying other performances such as mechanical strength, preferably 0.1 to 10 μm, and 0. 5 to 7.0 μm is more preferable, 1.0 to 6.0 μm is further preferable, and 1.5 to 5.5 μm is most preferable. When t2 is 0.1 μm or more, it is preferable from the viewpoint of ensuring other performance of the transfer region to be a product, and when it is 10 μm or less, it is preferable from the viewpoint of substrate peelability and thinning of the laminated body.

As a specific method for partially thinning t1, when the transfer layer is a coating film, a plate-shaped jig for removing the coating film is provided in the vicinity of P1 and scraped off before the drying of the coating film is completed. Alternatively, it can be carried out by a method of pressing a jig such as a wire bar against the coating film in the vicinity of P1 to make it thinner. When a jig such as a wire bar is pressed against it, film thickness non-uniformity may occur in the width direction, in which case t1 is evaluated at the thinnest portion. Further, there is a method of forming a transfer layer by multi-layer coating and changing the coating widths of the first layer and the second layer. In this case, the material of the wide layer and the narrow layer can be changed to make the wide layer a material that is easily torn.
As another method of partially thinning t1, when the transfer layer is an amorphous polymer, the temperature applied to the region near P1 is set to be less than Tg of the transfer layer, and the temperature applied to the P2 region is set to Tg or more of the transfer layer. By doing so, there is a method in which the plane orientation of the region near P1 is advanced and the plane orientation of the P2 region is suppressed. Further, when the transfer layer is a crystalline polymer, there is a method of partially heating the region near P1 to a temperature equal to or higher than the crystallization temperature.

<Adhesive strength between transfer layer and base material>
In the multi-layer film of the transfer layer and the base material of the present invention, it is preferable that the in-plane distribution of the adhesive force between the transfer layer and the base material is small in order to stably peel off the base material. The difference from the adhesive force in P2 is preferably less than 3N / 25mm, more preferably less than 1N / 25mm, and even more preferably less than 0.5N / 25mm.
The adhesive strength in P1 is preferably 0.001 to 5N / 25mm, more preferably 0.01 to 3N / 25mm, further preferably 0.1 to 1N / 25mm, and most preferably 0.15 to 0.8N / 25mm. .. If it is 0.001N / 25mm or more, unexpected peeling failure other than the peeling process of the base material can be prevented, and if it is 5N / 25mm or less, peeling failure in the peeling process (for example, zipping or transfer layer). Cracking) can be prevented.
Further, the higher the adhesive force in P2, the better the substrate peelability, but if the in-plane distribution of the adhesive force is large, wrinkles and creases occur on the substrate and the transferred body, and the substrate is sporadically. Since the peelability may deteriorate, it is preferable that P2 is set so that the in-plane distribution of the adhesive force is within the above-mentioned range. That is, when the base material of the transfer layer is peeled off, the base material and the transferred body do not have wrinkles or creases, and in order to perform stable peeling, the in-plane distribution of the adhesive force between the transfer layer and the base material is used. Is preferably small.
When the transfer layer of the present invention is formed by a coating method, the adhesive force between the transfer layer and the base material is controlled by adjusting the material of the transfer layer, the material of the base material, the internal strain of the transfer layer, and the like. be able to.

In the present specification, the adhesive strength between the transfer layer and the base material is determined after the transfer layer of the multi-layer film cut to a width of 25 mm and a length of 80 mm is bonded and fixed to a glass substrate via an acrylic pressure-sensitive adhesive sheet. Using a tensile tester (RTF-1210 manufactured by A & D Co., Ltd.), grasp the base material at one end (one side with a width of 25 mm) in the length direction of the test piece, and hold the temperature at 23 ° C and the relative humidity at 60%. In a 90 ° peeling test based on JIS K 6854-1: 1999 "Adhesive-Peeling Adhesive Strength Test Method-Part 1: 90 Degree Peeling" at a crosshead speed (chuck moving speed) of 300 mm / min under an atmosphere. evaluated.

<Elongation at break>
The elongation at break of the transfer layer of the present invention is not particularly limited, but is preferably 0.1 to 10%, more preferably 0.3 to 7%, still more preferably 0.5 to 5%. When the breaking elongation of the transfer layer is 0.1% or more, cracks are less likely to occur in the transfer layer, which is preferable, and when it is 10% or less, the substrate peelability is improved, which is preferable. Regarding the breaking elongation of the transfer layer, the transfer layer was placed outside the bending in the state of the multi-layer film of the transfer layer and the base material, and cracks did not occur by the cylindrical mandrel method according to JIS K5600-5-1. The strain of the transfer layer is calculated from the diameter.

<Elastic modulus>
The elastic modulus of the transfer layer of the present invention is not particularly limited, but is preferably 0.5 to 6.0 GPa, more preferably 1.5 to 4.5 GPa, still more preferably 2.0 to 3.5 GPa. When the elastic modulus of the transfer layer is 0.5 GPa or more, the peelability of the base material is improved, which is preferable.

In the present specification, the elastic modulus (tensile elastic modulus) of the transfer layer can be measured by using a film having a thick film thickness so as to maintain self-supporting property, if necessary. The elastic modulus of the film is such that the measurement direction is the longitudinal direction of the film, the film is cut out so that the measurement portion has a size of 10 cm × 1 cm, and the humidity is adjusted for 24 hours at 25 ° C. and a relative humidity of 60%, manufactured by Toyo Baldwin Co., Ltd. Using the universal tensile tester "STM T50BP", the stress at 0.1% elongation and 0.5% elongation is measured at a tensile speed of 10% / min, and the elastic modulus is calculated from the inclination.

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) of the transfer layer of the present invention and the resin used for the transfer layer is not particularly limited. The Tg is, for example, adjusted at 25 ° C. and a relative humidity of 10% for 24 hours, then the sample is enclosed in a measuring pan, and the Tg is raised at 20 ° C./min using a differential scanning calorimeter “DSC6200” manufactured by Seiko Instruments Co., Ltd. From the thermogram obtained by warming, it can be obtained as the intersection temperature between the baseline and the tangent line at the inflection point.

<Other characteristics>
The characteristic values other than the above are not particularly limited to the transfer layer of the present invention, and the same performance as that of a general known transfer film can be appropriately mounted, and the performance required for a general optical film can be appropriately mounted. Is preferably implemented as appropriate. Specific characteristic values include haze related to display characteristics, light transmittance, spectral characteristics, retardation, and wet heat durability of retardation, and humidity, temperature, and wet heat thermostat related to mechanical properties and processing suitability. The dimensional change rate, the equilibrium moisture absorption rate, the moisture permeability, the contact angle, etc. associated with the above can be mentioned.

<Layer structure>
The transfer layer of the present invention may be a single layer or may have a laminated structure of two or more layers. In the case of a laminated structure of two or more layers, the width of each layer constituting the transfer layer may be different, and for example, a laminated structure of two or more layers may be used for the purpose of imparting a film thickness difference between t1 and t2. .. It is also possible to stack functional layers to combine different functions.

<Main material>
The main material constituting the transfer layer of the present invention is not particularly limited, but a thermoplastic resin, a cured composition of a composition containing a reactive monomer, or the like can be preferably used.
The main material constituting the transfer layer is a component having the highest content (mass basis) among the components contained in the transfer layer.

-Thermoplastic resin The thermoplastic resin constituting the transfer layer of the present invention is not particularly limited, but it is preferable to include, for example, a polar structure that strengthens the interaction between polymer molecules from the viewpoint of improving brittleness and elasticity. It may be a crystalline polymer, an amorphous polymer, or a liquid crystal polymer. As specific examples, known vinyl aromatic resins (styrene resin, divinylbenzene resin, vinylpyridine resin, etc.), cyclic olefin resin, cellulose resin (cellulose acylate resin, cellulose ether resin, etc.), Examples thereof include polyester-based resins, polycarbonate-based resins, vinyl-based resins other than vinyl aromatic resins, polyimide-based resins, and polyarylate-based resins. Of these, styrene-based resins and cyclic olefin resins are preferable from the viewpoint of material hydrophobicity, and cellulose acylate resins are preferable from the viewpoint of brittleness.

Regarding the vinyl aromatic resin, specifically, paragraphs [0035] to [0041] of JP-A-2017-167514 describe vinyl aromatic resin and styrene resin, and they can be used as appropriate. ..

The cyclic olefin resin is specifically described in paragraphs [0047] to [0049] of JP-A-2017-215562, and can be used as appropriate.

Examples of the cellulose acylate resin include cellulose acetate, cellulose acetate propionate, cellulose propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate, cellulose acetate benzoate and the like. Among them, cellulose acetate and cellulose acetate propionate, which have microcrystalline properties and are excellent in mechanical strength and thermal dimensional stability, are preferable.
Examples of the polycarbonate resin include polycarbonate, polycarbonate containing a fluorene-modified structural unit of bisphenol A, and polycarbonate containing a 1,3-cyclohexylidene-modified structural unit of bisphenol A.
Examples of vinyl-based resins include polyethylene, polypropylene, polystyrene, polyvinylidene chloride, polyvinyl alcohol, and the like.

The thermoplastic resin constituting the transfer layer of the present invention may be of one type or may contain two or more types. Further, when the transfer layer is formed from multiple layers, the thermoplastic resin of each layer may be different.

-Curable composition A known curable composition can be used as another aspect of the transfer layer of the present invention. The curable composition is not particularly limited and includes known acrylic monomers, epoxy monomers and the like. Further, the curable composition may be mixed with the above-mentioned thermoplastic resin as appropriate.

Specifically, the reactive monomer is a compound having a cyclic aliphatic hydrocarbon group and an unsaturated double bond group described in paragraphs [0016] to [0044] of JP-A-2014-170130, and a fluorene ring. A compound having an unsaturated double bond group is described in the polyfunctional monomers and the like described in paragraphs [0109] to [0133] of JP2013-231955A, and can be appropriately used. Further, in order to impart water-glue adhesion to the polarizing film, the boronic acid monomer described in WO2015 / 053359 can also be used in combination.

-Polymerization Initiator The above-mentioned curable composition can contain a known polymerization initiator, and a photopolymerization initiator is preferable.
Examples of the photopolymerization initiator include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, azo compounds, peroxides, 2,3-dialkyldione compounds, disulfide compounds, and the like. Examples thereof include fluoroamine compounds, aromatic sulfoniums, lofin dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, coumarins and the like. Specific examples of the photopolymerization initiator, preferred embodiments, commercial products and the like are described in paragraphs [0133] to [0151] of JP-A-2009-0986658, and can be appropriately used.

"Latest UV Curing Technology" {Technical Information Association, Inc.} (1991), p. 159 and "Ultraviolet Curing System" by Kiyomi Kato (Published by General Technology Center in 1989), p. Various examples are also described in 65 to 148, which are useful for the present invention.

<Additives>
Known additives can be appropriately mixed with the transfer layer of the present invention. Known additives include low molecular weight plasticizers, leveling agents, oligomeric additives, polyester additives, retardation adjusters, fine particles, ultraviolet absorbers, deterioration inhibitors, peeling accelerators, visible light absorbers (dye), etc. Examples thereof include an infrared absorber, an antioxidant, a filler, a compatibilizer, a degree of polarization improver, and an anti-fading agent.
Generally, as the amount of these additives added increases, the transfer layer tends to tear easily, and these additives can also be used for the purpose of controlling the tearability of the transfer layer. It can also be used for the purpose of controlling the adhesive force between the transfer layer and the base material.
When the transfer layer is formed from multiple layers, the type and amount of additives in each layer may be different.

-Fine particles Fine particles can be added to the transfer layer of the present invention for the purpose of controlling the ease of tearing, slipperiness, preventing blocking, and the like. The amount of the fine particles added is preferably such that the transparency of the transfer layer is not impaired. As the fine particles, silica (silicon dioxide, SiO ₂ ) whose surface is coated with a hydrophobic group and which is in the form of secondary particles is preferably used. The fine particles include titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and phosphoric acid, together with silica or in place of silica. Fine particles such as calcium may be used. Examples of commercially available products include the trade name R972 or NX90S (both manufactured by Nippon Aerodil Co., Ltd.) for the fine particles.

-Polyester-based additive A known polyester-based additive can be appropriately mixed with the transfer layer of the present invention for the purpose of controlling the adhesive force between the transfer layer and the substrate. When a compound that reduces the surface energy difference between the transfer layer and the base material, a compound that contains a component whose glass transition temperature is lower than room temperature, or a compound that is permeable to the base material is added, the transfer layer and the base material become It has the effect of increasing the adhesive strength of the glass.
Specifically, the polyester-based additive is described in paragraphs [0075] to [0087] of JP2013-231955A, and can be used as appropriate.

-Leveling agent A known leveling agent (surfactant) can be appropriately mixed with the transfer layer of the present invention. Examples of the leveling agent include conventionally known compounds, and a fluorine-containing surfactant is particularly preferable. Specific examples thereof include the compounds described in paragraph numbers [0028] to [0056] in JP-A-2001-330725.

-Dye A dye can be appropriately added to the transfer layer of the present invention. The optimum absorption wavelength band of the dye varies depending on the design of the display device, and is, for example, a dye having a main absorption wavelength band at a wavelength of 460 to 520 nm (hereinafter referred to as dye A) or a wavelength of 560 to 620 nm. A dye having a main absorption wavelength band (hereinafter referred to as dye B) is preferable. Further, the transfer layer of the present invention may contain a dye other than the dye A and the dye B.

The dye A is not particularly limited as long as it has a main absorption wavelength band at a wavelength of 460 to 520 nm, and various dyes can be used. Many of the dyes A show fluorescence.
In the present invention, having the main absorption wavelength band in the wavelength XX to YY nm means that the wavelength showing the maximum absorption wavelength exists in the wavelength region XX to YY nm in the visible light absorption spectrum (wavelength region 380 to 750 nm). .. Therefore, if this wavelength is within the wavelength region, the entire absorption band including this wavelength may be within the wavelength region or may extend beyond the wavelength region. Further, when a plurality of maximum absorption wavelengths are present, the maximum absorption wavelengths exhibiting non-highest absorbance may exist outside the wavelength region XX to YY nm. When there are a plurality of wavelengths indicating the maximum absorption wavelength, one of them may be present in the above wavelength region.

Specific examples of the dye A include pyrrole methine (PM) -based, rhodamine (RH) -based, boron dipyrromethene (BODIPY) -based, and squaric (squarine, SQ) -based dyes. Can be mentioned. For example, a commercially available product such as FDB-007 (trade name, merocyanine dye, manufactured by Yamada Chemical Industry Co., Ltd.) can also be preferably used as the dye A.

The dye B is not particularly limited as long as it has a main absorption wavelength band at a wavelength of 560 to 620 nm, and various dyes can be used. Many of the dyes B have weaker fluorescence than the dye A or do not show fluorescence.
Specific examples of the dye B include tetraazaporphyrin (TAP) -based, squaric-based, and cyanine (CY) -based dyes. In addition, commercially available products such as PD-311S (trade name, tetraazaporphyrin dye, manufactured by Yamamoto Chemicals, Inc.) and FDG-006 (trade name, tetraazaporphyrin dye, manufactured by Yamada Chemicals, Inc.) are also preferably used as dye B. be able to.

-Anti-fading agent An anti-fading agent can be appropriately added to the transfer film of the present invention. Examples of the anti-fading agent used in the present invention include the antioxidants described in paragraphs [0143] to [0165] of International Publication No. 2015/005398, the radical scavengers described in the same [0166] to [0199], and the same. The deterioration inhibitor according to [0205] to [0206] can be used.

<< Base material >>
The substrate used for forming the transfer layer by the coating method preferably has a film thickness of 5 to 100 μm, more preferably 10 to 75 μm, and even more preferably 15 to 55 μm. When the film thickness is 5 μm or more, sufficient mechanical strength can be easily secured and failures such as curl, wrinkles, and buckling are unlikely to occur, which is preferable. Further, when the film thickness is 100 μm or less, the substrate peelability tends to be improved, which is preferable. The mechanism by which the substrate peeling property is improved when the film thickness of the substrate is thin is unknown, but it is considered that the transfer layer is easily torn because the peeling angle of the substrate approaches an acute angle.

The surface energy of the base material is not particularly limited, but the relationship between the surface energy of the material or coating solution of the transfer layer and the surface energy of the surface on the side where the transfer layer of the base material is formed is adjusted. Allows the adhesive force between the transfer layer and the substrate to be adjusted. If the surface energy difference is small, the adhesive force tends to increase, and if the surface energy difference is large, the adhesive force tends to decrease, which can be appropriately set.

The surface energy of the substrate can be calculated from the contact angle values of water and methylene iodide using the Owens method. For the measurement of the contact angle, for example, DM901 (contact angle meter manufactured by Kyowa Interface Science Co., Ltd.) can be used.
The surface energy on the side of forming the transfer layer of the base material is not particularly limited, but is preferably 41.0 to 48.0 mN / m, more preferably 42.0 to 48.0 mN / m. .. When the surface energy is 41.0 mN / m or more, the uniformity of the film thickness of the transfer layer can be enhanced, and when it is 48.0 mN / m or less, the peeling force of the transfer layer from the substrate is within an appropriate range. It is preferable because it is easy to control.

The surface unevenness of the base material is not particularly limited, but the surface energy, hardness, and surface unevenness of the surface of the transfer layer and the surface energy of the surface opposite to the side on which the transfer layer of the base material is formed are defined. Depending on the relationship with hardness, for example, it can be adjusted for the purpose of preventing adhesion failure when the multilayer film of the present invention is stored in a long roll form. Increasing the surface unevenness tends to suppress the adhesion failure, and reducing the surface unevenness tends to reduce the surface unevenness of the transfer layer and reduce the haze of the transfer layer, which can be appropriately set.

As such a base material, a known material or film can be appropriately used. Specific examples thereof include polyester-based polymers, olefin-based polymers, cycloolefin-based polymers, (meth) acrylic-based polymers, cellulosic-based polymers, and polyamide-based polymers. Further, for the purpose of adjusting the surface property of the base material, surface treatment can be appropriately performed. For example, corona treatment, room temperature plasma treatment, saponification treatment and the like can be performed to reduce the surface energy, and silicone treatment, fluorine treatment, olefin treatment and the like can be performed to increase the surface energy.

<< Preparation of transfer layer >>
The transfer layer of the present invention can be produced by a method of forming a coating layer on a substrate by a known method, and when the main material of the transfer layer is a thermoplastic resin, a known solution film forming method and melting can be used. According to the extrusion method, co-flowing, co-extruding, stretching and the like can be combined as appropriate.

In the coating method, the material of the transfer layer is applied to the film as the base material to form the coating layer. In order to control the adhesiveness with the coating layer, a mold release agent or the like may be appropriately applied to the surface of the base material in advance. The coating layer can be used by laminating it with the polarizing layer via an adhesive or an adhesive in a later step and then peeling off the base material. In a state where the polymer solution or the coating layer is laminated on the base material, the base material can be appropriately stretched to adjust the optical properties and mechanical properties.

In the solution film forming method, a solution in which the material of the transfer layer is dissolved in an organic solvent or water is prepared, and after appropriately performing a concentration step, a filtration step, or the like, the solution is uniformly cast on the support. Next, the dry film is peeled off from the support, and both ends of the web are appropriately grasped with clips or the like to dry the solvent in the drying zone. Further, the stretching may be separately carried out during the drying of the film or after the drying is completed.

The solvent used in the solution of the transfer layer material should be able to dissolve or disperse the transfer layer material, be likely to have a uniform surface shape in the coating process and drying process, ensure liquid storage stability, and have an appropriate saturated vapor pressure. It can be appropriately selected from the viewpoint of having, etc.

The melt extrusion method is specifically described in paragraphs [805] to [0090] of JP-A-2017-215562, and can be used as appropriate.

The transfer layer is preferably hydrophilized by a known glow discharge treatment, corona discharge treatment, alkali saponification treatment, or the like, and the corona discharge treatment is most preferably used. It is also preferable to apply the method disclosed in Japanese Patent Application Laid-Open No. 6-94915, Japanese Patent Application Laid-Open No. 6-118232, and the like.

The obtained film can be subjected to a heat treatment step, a superheated steam contact step, an organic solvent contact step, or the like, if necessary. Further, it can be surface-treated and applied as a hard coat film, an antiglare film, and an antireflection film.

<< Adhesive layer >>
The material used as the adhesive layer of the present invention is not particularly limited, and known adhesives and pressure-sensitive adhesive compositions can be used.

-Curing adhesive As the curing adhesive, an ultraviolet curable adhesive can be preferably used. The type of the ultraviolet curable adhesive is not particularly limited, but is the epoxy-based ultraviolet curable adhesive described in JP-A-2015-187744 and the acrylate-based ultraviolet curable adhesive described in JP-A-2015-11094. It is preferable to use an agent.

-Water-based adhesive As the water-based adhesive, an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral) or latex of a vinyl-based polymer (for example, polybutyl acrylate) can be used.

-Adhesive composition A pressure-sensitive adhesive (adhesive) can be used as a pressure-sensitive adhesive. As for the pressure-sensitive adhesive composition, specifically, the pressure-sensitive adhesive composition described in paragraphs [0106] to [0111] of JP-A-2017-215562 and the cross-linking agent described in paragraph [124] shall be appropriately used. Can be done.

<Thickness of adhesive layer>
The thickness of the adhesive layer of the present invention is not particularly limited, but in the case of a curable adhesive, 0.1 to 10 μm is preferable from the viewpoint of achieving both adhesion to the transferred body and curability of adhesion. , 0.5 to 5 μm is more preferable, and 1 to 3 μm is even more preferable. Further, in the case of a water-based adhesive, 1 to 1000 nm is preferable, 10 to 500 nm is more preferable, and 30 to 300 nm is further preferable, from the viewpoint of achieving both adhesiveness to the transferred body and dryness of the adhesive.

<< Laminated body >>
The transfer layer of the present invention includes a substrate, a transfer layer, and an adhesive layer in this order. The laminate of the present invention can be produced by a known method, and the transfer layer and the adhesive layer are adjacent to each other, and the transfer layer is laminated so as to be wider than the adhesive layer. That is, in the laminated body of the present invention, the area of the transfer layer is larger than the area of the adhesive layer. Typically, the laminate of the present invention is rectangular (which may be elongated) (and the substrate, transfer layer, and adhesive layer are rectangular), and the widthwise ends of the transfer layer. The adhesive layer can be laminated so that is exposed (see FIGS. 1 and 2).
When the laminated body of the present invention is a long laminated body, the transferred body to be laminated via an adhesive and the base material including the transfer layer are also long-shaped, and are applied by roll-to-roll. It is preferable to be able to match. FIG. 1 shows a schematic diagram of the case where the laminated body of the present invention is a long laminated body as an example of the laminated body.
The laminate of the present invention is excellent in terms of substrate peelability and defects. Therefore, by using the laminated body of the present invention, for example, it is possible to provide a laminated film of a transfer layer and an adhesive layer useful as an optical film used in a liquid crystal display device or the like with a high yield. Further, by using the laminated body of the present invention, it is possible to provide a liquid crystal display device which is less likely to cause light unevenness and has excellent reliability.

<Polarizing film>
A polarizing film can also be arranged on the side of the adhesive layer of the present invention opposite to the transfer layer. As the polarizing film preferably used, for example, a polyvinyl alcohol film immersed in an iodine solution and stretched can be used. The transfer layer of the present invention can be attached to one side or both sides of the polarizing film via the above-mentioned adhesive layer.

<Peeling of the base material of the transfer layer>
In the step after producing the laminate of the present invention, there is a step of peeling and removing the base material from the transfer layer. The peeling removal of the base material can be carried out, for example, by the same method as the peeling step of the separator (peeling film) used for a normal adhesive, and the peeling timing can be the next step or once winding into a roll. It can be carried out at any time, such as another process after that.

<Anti-static layer>
An antistatic layer can be further laminated on the laminate including the transfer layer of the present invention. The antistatic layer is not particularly limited as long as it contains an antistatic agent, but from the viewpoint of obtaining good antistatic performance, the elastic modulus of the layer is preferably less than 1 GPa and preferably 0.1 GPa or less. It is more preferably 0.05 GPa or less, and even more preferably 0.05 GPa or less.
Specific examples thereof include a pressure-sensitive adhesive composition containing an antistatic agent, and examples thereof include the antistatic agent described in paragraphs [0112] to [0122] of JP-A-2017-215562 and the antistatic agent. The pressure-sensitive adhesive composition can be used as appropriate. The antistatic layer may be, for example, a pressure-sensitive adhesive composition to which an antistatic agent is added so as to have a surface resistance value of about 1 × 10 ⁸ to 1 × 10 ¹¹ Ω / cm ² , such as a release film or an optical film. It can be formed by applying it to a substrate.

<< Display device >>
The laminate of the present invention can be used in a known liquid crystal display device or an organic electroluminescence display device.

Hereinafter, the present invention will be described in more detail with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.

<< Preparation of multi-layer film >>

<Multi-layer film A1>
A peelable double glazing film was prepared by the method shown below.
1) Preparation of coating liquid A coating liquid 1 for forming a multi-layer film was prepared with the composition shown below.

2) Composition of coating liquid 1 SGP-10 50.0 parts by mass Epocross RPS-1005 48.7 parts by mass Byron 550 1.0 part by mass A-19-1 0.3 parts by mass Ethyl acetate 600.0 parts by mass The coating liquid was filtered with a filter having an absolute filtration accuracy of 1 μm to obtain a coating liquid 1S.

The materials used are shown below.
・ SGP-10: Polystyrene [manufactured by PS Japan]
Epocross RPS-1005: Styrene-oxazoline copolymer [manufactured by Nippon Shokubai]
・ Byron 550 [manufactured by Toyobo Co., Ltd.]
Fluorine-containing copolymer (A-19-1): A polymer having the following structure. It was produced in the same manner as in Synthesis Example 22 ([0183] to [0185]) of JP-A-2018-5215.

3) Coating of multi-layer film A commercially available polyethylene terephthalate film, Embret S38 (thickness 38 μm, width 1340 mm, manufactured by Unitika Ltd.) was used as a base material (coating base material), and a coating liquid 1S was used. A multi-layer film A1 was obtained by producing a coating film having a coating film width of 1320 mm and a film thickness (t2) near the center of the width after drying so as to have the values shown in Table 1. Specifically, it is applied under the condition of a transport speed of 30 m / min by the die coating method using the slot die described in Japanese Patent Application Laid-Open No. 2006-122889, and the portion 20 mm from the edge of the coating film at both ends is immediately after application. The coating film was scraped off so that the film thickness (t1) after drying became the value shown in Table 1, and the film was dried at 105 ° C. for 30 seconds. Then it was wound up.

<Multi-layer film A2>
A film was produced in the same manner as the multi-layer film A1 except that the coating liquid of the multi-layer film A1 was replaced with the following coating liquid 2, to obtain a multi-layer film A2.

2) Composition of coating liquid 2 AS-70 100.0 parts by mass SMA2000P 5.0 parts by mass Byron 500 0.9 parts by mass Surface active agent 1 0.1 parts by mass Methyl acetate 250.0 parts by mass acetonitrile 225.0 parts by mass 25.0 parts by mass of ethanol The obtained coating liquid was filtered with a filter having an absolute filtration accuracy of 1 μm.

The materials used are shown below.
-AS-70: Acrylonitrile-styrene copolymer resin [manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.]
・ SMA2000P [Kawahara Yuka Co., Ltd.]
・ Byron 500 [manufactured by Toyobo Co., Ltd.]
-Surfactant 1: A surfactant having the following structure was used.

<Multi-layer film A3>
Of the coating liquid of the multi-layer film A1, the amount of Byron 550 added was changed from 1.0 part by mass to 3.0 parts by mass, and the base material was changed to a polyethylene terephthalate film having corona-treated 30 mm at each end. A film was produced in the same manner as the multilayer film A1 to obtain a multilayer film A3.

<Multi-layer film A4>
The coating liquid of the multi-layer film A1 is replaced with the coating liquid 4 below, the coating base material is replaced with a commercially available polyethylene terephthalate film, Embret SK50 (thickness 50 μm, width 1340 mm, manufactured by Unitika Ltd.), and A film was produced in the same manner as the multilayer film A1 except that the drying temperature of the coating film was changed to 120 ° C. to obtain a multilayer film A4.

2) Composition of coating liquid 4 SGP-10 85.6 parts by mass Zyrone S201A 10.0 parts by mass Byron 550 0.10 parts by mass Dye 1 0.33 parts by mass Anti-fading agent 1 4.0 parts by mass Surface active agent 20 .1 part by mass Matting agent 1 0.002 part by mass Toluene 767.3 part by mass The obtained coating liquid was filtered with a filter having an absolute filtration accuracy of 1 μm.

The materials used are shown below.
・ SGP-10: Polystyrene [manufactured by PS Japan]
-Zylon S201A: Polyphenylene ether resin [manufactured by Asahi Kasei Corporation]
・ Byron 550 [manufactured by Toyobo Co., Ltd.]
-Dye 1: A dye having the following structure was used.

-Anti-fading agent 1: A surfactant having the following structure was used.

-Surfactant 2: A surfactant having the following structure was used. In the following structural formula, t-Bu means a tert-butyl group.

-Mat agent 1: Silicon dioxide fine particles, NX90S [manufactured by Nippon Aerosil Co., Ltd.]

<< Fabrication of polarizing plate >>
A polarizing plate as a laminated body was produced by using the above-mentioned multi-layer film, an adhesive, a polarizing element, and an opposed film.
1) Preparation of adhesive A polymerizable compound, an initiator and a sensitizer were mixed by the method shown below to prepare an adhesive composition.

2) Composition of adhesive composition Epiol EH-N 10.0 parts by mass Ricaresin DME-100 20.0 parts by mass Serokiside 2021P 70.0 parts by mass CPI-100P 1.0 parts by mass IRGACURE290 4.0 parts by mass DarocurITX 0. 5 parts by mass

The materials used are shown below.
・ Epiol EH-N [manufactured by NOF CORPORATION]
・ Rica Resin DME-100 [manufactured by New Japan Rika Co., Ltd.]
・ Selokiside 2021P [manufactured by Daicel Corporation]
・ CPI-100P [manufactured by Sun Appro Co., Ltd.]
・ IRGACURE290 [made by BASF]
・ DarocurITX [made by BASF]

3) Preparation of facing film According to Example 1 of JP-A-2015-227458, a polymethylmethacrylate film having a thickness of 60 μm was prepared and used as a facing film A1.

4] Surface treatment of the double glazing film Corona treatment was performed on the surface of the double glazing film prepared above on the side opposite to the interface on the substrate side and the facing film A1.

5] Preparation of Polarizer According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, a peripheral speed difference was applied between the two pairs of nip rolls and stretched in the longitudinal direction to prepare a splitter having a film thickness of 15 μm.

6) Laminating The above-mentioned surface-treated multi-layer film, polarizing element, and counter film A1 were laminated in this order to obtain a polarizing plate. At this time, the surface-treated surface of the film was arranged so as to be on the polarizing element side, and the above-mentioned adhesive composition was used for adhesion. Further, the absorbent shaft of the polarizing element, the multi-layer film, and the opposed film A1 were laminated by roll-to-roll so as to be parallel to each other in the longitudinal direction. At this time, the coating width of the adhesive composition was set to 1300 mm, and both ends of the adhesive composition were laminated so as to be in the P1 region of the transfer layer. Subsequently, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.), ultraviolet rays having an irradiation amount of 300 mJ / cm ² were irradiated to cure the mixture. The obtained polarizing plate was cut and the cross section was observed with an optical microscope, and it was confirmed that the thickness of the adhesive (adhesive layer) was 2.5 μm on both the multilayer film side and the facing film side.

7) Peeling of the base material With respect to the laminated body after the base material of the multi-layer film is continuously peeled off from the polarizing plate which is the laminated body produced above by using the same device as the peeling device of the separator, and the base material is peeled off. , The cut state of the transfer layer near P1 was visually confirmed. The results (base material peelability) were judged as follows and are shown in Table 1.
<Evaluation of substrate peelability>
A: The substrate immediately after peeling could be stably peeled without creases or wrinkles, and the transfer layer after peeling the substrate was good without any defects.
B: The substrate immediately after peeling had sporadic wrinkles and wrinkles, but the transfer layer after peeling the substrate was good with no defects.
C: The substrate immediately after peeling may sporadically have creases or wrinkles, and a slight amount of dust may be generated in the transfer layer after the substrate is peeled off, or a slight crack may occur in the transfer layer.
D: Scratches and wrinkles were constantly confirmed on the base material immediately after peeling, and dust was generated on the transfer layer after the base material was peeled off, and the transfer layer was cracked. The work could not be carried out.

8) Coating of adhesive The acrylic pressure-sensitive adhesive containing the antistatic agent coated on the separator was transferred onto the surface of the prepared polarizing plate from which the base material was peeled off, and the processing of the polarizing plate was completed.

In Comparative Example 3, the substrate immediately after peeling was constantly found to be squeezed and peeled while making an abnormal noise.

From Table 1 above, the transfer film (laminated body) of the present invention was excellent in substrate peelability and had few defects. From this, it was found that products such as polarizing plates can be produced with good yield by using the laminate of the present invention.

According to the present invention, it is possible to provide a laminate including a transfer layer and an adhesive layer having good substrate peelability and few defects.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on December 26, 2018 (Japanese Patent Application No. 2018-243277), the contents of which are incorporated herein by reference.

Claims (4)

The base material, the transfer layer, and the adhesive layer are included in this order, the transfer layer and the adhesive layer are adjacent to each other, the area of the transfer layer is wider than the area of the adhesive layer, and the in-plane distribution is in the film thickness of the transfer layer. The feature is that the film thickness t1 of the transfer layer at the position P1 where the end of the adhesive layer is in contact with the transfer layer is thinner than the film thickness t2 of the transfer layer at the position P2 inside it. Laminated body. The laminate according to claim 1, wherein the difference between the adhesive force fa1 between the transfer layer and the substrate in P1 and the adhesive force fa2 between the transfer layer and the substrate in P2 is less than 3N / 25 mm. body. The laminate according to claim 1 or 2, wherein the main material of the transfer layer is a thermoplastic resin. The laminate according to any one of claims 1 to 3, wherein the laminate is a long laminate.

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