CN118325530A - Adhesive composition, laminate, and optical semiconductor device - Google Patents

Adhesive composition, laminate, and optical semiconductor device Download PDF

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Publication number
CN118325530A
CN118325530A CN202410034474.1A CN202410034474A CN118325530A CN 118325530 A CN118325530 A CN 118325530A CN 202410034474 A CN202410034474 A CN 202410034474A CN 118325530 A CN118325530 A CN 118325530A
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adhesive layer
optical semiconductor
mass
layer
meth
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Chinese (zh)
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山本敦士
浅井量子
小坂尚史
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Nitto Denko Corp
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Nitto Denko Corp
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Publication of CN118325530A publication Critical patent/CN118325530A/en
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J4/00—Adhesives based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; adhesives, based on monomers of macromolecular compounds of groups C09J183/00 - C09J183/16
    • C09J4/06—Organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond in combination with a macromolecular compound other than an unsaturated polymer of groups C09J159/00 - C09J187/00
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/10—Esters
    • C08F220/20—Esters of polyhydric alcohols or phenols, e.g. 2-hydroxyethyl (meth)acrylate or glycerol mono-(meth)acrylate
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F265/00—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00
    • C08F265/04—Macromolecular compounds obtained by polymerising monomers on to polymers of unsaturated monocarboxylic acids or derivatives thereof as defined in group C08F20/00 on to polymers of esters
    • C08F265/06—Polymerisation of acrylate or methacrylate esters on to polymers thereof
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/04—Non-macromolecular additives inorganic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • C09J7/381—Pressure-sensitive adhesives [PSA] based on macromolecular compounds obtained by reactions involving only carbon-to-carbon unsaturated bonds
    • C09J7/385—Acrylic polymers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/52—Encapsulations
    • H01L33/56—Materials, e.g. epoxy or silicone resin
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/326—Applications of adhesives in processes or use of adhesives in the form of films or foils for bonding electronic components such as wafers, chips or semiconductors

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Polymers & Plastics (AREA)
  • Health & Medical Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Computer Hardware Design (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Adhesive Tapes (AREA)

Abstract

Provided are an adhesive composition, a laminate, and an optical semiconductor device, which can produce an adhesive layer that has excellent anti-reflection properties, high haze values, excellent storage stability, and suppressed turbidity when adhered to an adherend. The adhesive composition of the present invention contains a base polymer having a refractive index of 1.4 or more or a polymerizable compound forming the base polymer and light-diffusing fine particles, wherein the base polymer may have a structural unit derived from a high refractive index monomer, the total light transmittance of the adhesive layer when the adhesive layer is formed is 69% or less, the content ratio of the light-diffusing fine particles in the adhesive layer when the adhesive layer is formed is X1 mass% and the content ratio of the structural unit derived from the high refractive index monomer in the base polymer is X2 mass%, and the following formulae (1) and (2) are satisfied, and X2 is less than 29.8. 1.2X1+0.08X2+84.9.gtoreq.90 (1); 2.3X1-0.46X2+105.ltoreq.150 (2).

Description

Adhesive composition, laminate, and optical semiconductor device
Technical Field
The invention relates to an adhesive composition, a laminated sheet and an optical semiconductor device. More specifically, the present invention relates to an adhesive composition, a laminate sheet having an adhesive layer formed from the adhesive composition, and an optical semiconductor device having a structure in which the laminate sheet seals an optical semiconductor element.
Background
In recent years, as a next-generation Display device, a self-luminous Display device represented by a Mini/Micro LED Display device (Mini/Micro LIGHT EMITTING Diode Display) has been designed. As a basic configuration of a mini/micro LED display device, a substrate in which a plurality of micro optical semiconductor elements (LED chips) are densely arranged is used as a display panel, the optical semiconductor elements are sealed with a sealing material, and a cover member such as a resin film or a glass plate is laminated on the outermost layer.
In an image display device including a self-luminous display device such as a mini/micro LED display device, wiring (metal wiring) of a metal oxide such as metal or ITO is arranged on a substrate of a display panel. Such a display device has a problem that, for example, when the light is turned off, the appearance of the screen is poor and the design is poor due to the reflection of light by the metal wiring or the like. Therefore, as a sealing material for sealing the optical semiconductor element, a technique using an antireflection layer for preventing reflection caused by the metal wiring is adopted.
Patent document 1 discloses an adhesive sheet which is a laminate of a colored adhesive layer and a colorless adhesive layer, the colorless adhesive layer being positioned so as to be in contact with an optical semiconductor element. The description is: when the pressure-sensitive adhesive sheet is brought into contact with and conforms to the concave-convex shape formed by the substrate and the optical semiconductor element provided on the substrate, the designability can be improved and uneven brightness can be suppressed when the image display device is turned off.
Prior art literature
Patent literature
Patent document 1: japanese patent laid-open No. 2020-169262
Disclosure of Invention
Problems to be solved by the invention
In order to further suppress the luminance unevenness and to further improve the extraction efficiency of light emitted from the optical semiconductor element, it is sometimes required to improve the haze of the sealing material. In order to improve the haze of the sealing material, the use of a high refractive index material is conceivable. However, when the blending amount of the high refractive index material increases, there are problems that haze is not improved until the sealing material becomes cloudy. In addition, when the sealing material has curability, it is required that the sealing material has excellent storage stability without curing until the use in order to exhibit the following property to the concave-convex shape at the time of bonding.
The present invention has been made in view of such a situation, and an object thereof is to provide an adhesive composition capable of producing an adhesive layer which is excellent in antireflection property when adhered to an adherend, has a high haze value, is excellent in storage stability, and is suppressed in turbidity.
Solution for solving the problem
As a result of intensive studies to achieve the above object, the present inventors have found that an adhesive layer having excellent anti-reflection properties, a high haze value, excellent storage stability and suppressed turbidity when adhered to an adherend can be produced using a specific adhesive composition. The present invention has been completed based on these findings.
That is, the present invention provides an adhesive composition comprising a base polymer having a refractive index of 1.4 or more or a polymerizable compound forming the base polymer and light diffusing fine particles,
The base polymer optionally has structural units derived from high refractive index monomers,
The total light transmittance of the adhesive layer when forming the adhesive layer is 69% or less,
When the content of the light diffusing fine particles in the pressure-sensitive adhesive layer at the time of forming the pressure-sensitive adhesive layer is X1 mass% and the content of the structural units derived from the high refractive index monomer in the base polymer is X2 mass%, the following formulas (1) and (2) are satisfied,
X2 is less than 29.8.
1.2X1+0.08X2+84.9≥90 (1)
2.3X1-0.46X2+105≤150 (2)
The base polymer is an acrylic polymer having a structural unit derived from a high refractive index monomer, and the high refractive index monomer preferably contains a monomer having a refractive index of 1.5 or more.
The adhesive composition preferably contains a colorant.
The present invention also provides a laminate sheet comprising an adhesive portion including an adhesive layer formed from the adhesive composition.
The laminate sheet preferably includes an antiglare layer and/or an antireflection layer on one of the outermost surfaces.
The thickness of the adhesive portion is preferably 500 μm or less.
The laminated sheet is preferably a sheet for sealing 1 or more optical semiconductor elements disposed on a substrate.
The present invention also provides an optical semiconductor device including: the semiconductor device includes a substrate, an optical semiconductor element disposed on the substrate, and the laminate sheet or cured product sealing the optical semiconductor element.
ADVANTAGEOUS EFFECTS OF INVENTION
The adhesive composition of the present invention can produce an adhesive layer which has excellent anti-reflection properties, a high haze value, excellent storage stability, and suppressed turbidity when adhered to an adherend. Therefore, the laminate sheet provided with the adhesive layer is excellent in antireflection and light diffusion properties when used to seal an optical semiconductor element. Further, the laminate is excellent in storage stability, and is excellent in the following property of the irregularities when the laminate is bonded to an optical semiconductor element and in the curability when the laminate is post-cured, and is excellent in the sealing property of the optical semiconductor element. Further, the haze is suppressed, and thus the light extraction efficiency is excellent.
Drawings
FIG. 1 is a cross-sectional view of a laminate according to one embodiment of the present invention.
FIG. 2 is a cross-sectional view of a laminate sheet of another embodiment of the present invention.
Fig. 3 is a partial cross-sectional view illustrating an embodiment of an optical semiconductor device using the laminate sheet shown in fig. 1.
Fig. 4 is a partial cross-sectional view showing an embodiment of an optical semiconductor device using the laminate sheet shown in fig. 2.
Fig. 5 is a partial cross-sectional view showing another embodiment of an optical semiconductor device using the laminate sheet shown in fig. 2.
Description of the reference numerals
1. Laminate sheet
2. Adhesive part
21. Adhesive layers of the invention
22. Non-diffusion functional layer
3. Release liner
4. Base material part
41. Substrate film
42. Functional layer
5. Substrate board
6. Optical semiconductor element
7. Sealing resin layer
71. Diffusion functional coloring layer
72. Non-diffusion functional layer
10. Optical semiconductor device
Detailed Description
[ Adhesive composition ]
The adhesive composition of the present invention contains at least a base polymer having a refractive index of 1.4 or more, a polymerizable compound forming the base polymer, and light-diffusing fine particles. That is, the adhesive composition contains a base polymer having a refractive index of 1.4 or more, or a base polymer containing a polymerizable compound and formed at the time of forming an adhesive layer, the refractive index of the base polymer is 1.4 or more. Examples of the polymerizable compound include a monomer component, an oligomer, and a polymer having a polymerizable functional group.
The base polymer is a base polymer in an adhesive layer formed from the adhesive composition. In the present specification, the base polymer means a main component of polymer components in the adhesive constituting the adhesive layer, for example, a polymer component having a content exceeding 50 mass%. The content of the base polymer in the pressure-sensitive adhesive layer is preferably 60 mass% or more, more preferably 70 mass% or more, based on 100 mass% of the total pressure-sensitive adhesive layer.
The refractive index of the base polymer is calculated as a total value of the refractive indices of all the monomer components constituting the base polymer divided by the content ratio. For example, the refractive index of the base polymer when the monomer component of refractive index a is a mass%, the monomer component of refractive index B is B mass%, the monomer component of refractive index C is C mass%, and (a+b+c=100) is calculated as a/a+b/b+c/C.
In the present specification, the "monomer component" refers to a compound having only 1 polymerizable functional group, and does not include a compound having 2 or more polymerizable functional groups such as polyfunctional (meth) acrylate.
The refractive index of the monomer component was measured using an Abbe refractometer under conditions of a measurement wavelength of 589nm and a measurement temperature of 25 ℃. As the Abbe refractometer, the model "DR-M4" manufactured by the company ATAGO or its equivalent may be used. The nominal value of the refractive index at 25 ℃ may be adopted when provided by the manufacturer or the like.
The refractive index of the base polymer is 1.4 or more, preferably 1.42 or more, more preferably 1.43 or more, and still more preferably 1.44 or more as described above. By the refractive index being 1.4 or more, an adhesive layer having a high haze value can be easily obtained.
The base polymer may or may not have structural units derived from a high refractive index monomer. The content of the structural unit derived from the high refractive index monomer in the base polymer (corresponding to X2 described later) is less than 29.8 mass%, preferably 29.7 mass% or less, more preferably 28 mass% or less, still more preferably 26 mass% or less, and particularly preferably 24 mass% or less, based on 100 mass% of the total amount of the adhesive layer. When the content ratio is less than 29.8 mass%, turbidity of the adhesive layer is suppressed.
The refractive index of the high refractive index monomer is, for example, 1.48 or more, preferably 1.49 or more, more preferably 1.5 or more, and still more preferably 1.51 or more. The high refractive index monomer may be used alone or in combination of two or more.
The pressure-sensitive adhesive composition satisfies the following formulas (1) and (2) when the content of the light-diffusing fine particles in the pressure-sensitive adhesive layer at the time of forming the pressure-sensitive adhesive layer is X1 mass% and the content of the structural units derived from the high refractive index monomer is X2 mass%. X1 and X2 are each equivalent to a proportion of 100 mass% relative to the nonvolatile components (e.g., all components excluding the solvent) in the adhesive composition.
1.2X1+0.08X2+84.9≥90 (1)
2.3X1-0.46X2+105≤150 (2)
The value represented by the above formula (1) is 90 or more, preferably 95 or more, and more preferably 98 or more. The value represented by the above formula (1) is a criterion of the haze value of the pressure-sensitive adhesive layer, and the higher the haze value is, the higher the pressure-sensitive adhesive layer tends to be obtained. The value represented by the above formula (1) may be 120 or less, or 100 or less, for example.
The value represented by the above formula (2) is 150 or less, preferably 145 or less, and more preferably 130 or less. The value represented by the above formula (2) is a standard of the curing rate of the pressure-sensitive adhesive layer after storage, and the pressure-sensitive adhesive layer tends to be more excellent in storage stability as the value approaches 100. The value represented by the above formula (2) may be, for example, 70 or more, or 90 or more.
The glass transition temperature (Tg) of the base polymer is preferably less than-28deg.C, more preferably-30deg.C or less. When the glass transition temperature is less than-28 ℃, the pressure-sensitive adhesive layer is excellent in flexibility and following up the concave-convex shape. The glass transition temperature is preferably-60℃or higher, more preferably-50℃or higher, and still more preferably-45℃or higher.
The glass transition temperature is a value calculated based on the following formula (X) (Fox formula).
1/Tg＝W1/Tg1+W2/Tg2+···+Wn/Tgn(X)
In the formula (X), tg represents a glass transition temperature (unit: K), tgi (i=1, 2 the expression of the glass transition temperature (unit: N) represents the formation of a homopolymer from the monomers i glass transition temperature (unit. ]
The formula (X) is a calculation formula in the case where the polymer is composed of n monomer components of monomer 1, monomer 2, & gtand monomer n.
In the present specification, "glass transition temperature (Tg) at the time of forming a homopolymer (sometimes simply referred to as" Tg of homopolymer ") means" glass transition temperature (Tg) of a homopolymer of the monomer ", and specifically, values are listed in" Polymer Handbook "(3 rd edition, john Wiley & Sons, inc, 1987). The Tg of a homopolymer of a monomer not described in the above-mentioned document refers to a value obtained by, for example, the following measurement method, in addition to a monomer having a polyorganosiloxane skeleton (see japanese patent application laid-open No. 2007-51271). Specifically, 100 parts by mass of monomer, 0.2 part by mass of 2,2' -azobisisobutyronitrile and 200 parts by mass of ethyl acetate as a polymerization solvent were charged into a reactor equipped with a thermometer, a stirrer, a nitrogen inlet pipe and a reflux condenser, and stirred for 1 hour while introducing nitrogen. After oxygen in the polymerization system was removed therefrom, the temperature was raised to 63℃and the reaction was carried out for 10 hours. Then, the mixture was cooled to room temperature to obtain a homopolymer solution having a solid content of 33% by mass. The homopolymer solution was then cast onto a release liner and dried to produce a test specimen (sheet-like homopolymer) having a thickness of about 2 mm. Then, the test specimen was punched into a disk shape having a diameter of 7.9mm, and clamped by parallel plates, and viscoelasticity was measured by a shear mode using a viscoelasticity tester (trade name "ARES", manufactured by Rheometrics, inc.) while imparting a shear strain at a frequency of 1Hz at a temperature range of-70 to 150℃at a temperature rise rate of 5℃per minute, and the peak top temperature of tan. Delta. Was defined as Tg of the homopolymer.
Examples of the base polymer include known or conventional polymers, such as acrylic polymers, urethane acrylate resins, urethane resins, rubber resins, epoxy acrylate resins, oxetane resins, silicone acrylic resins, polyester resins, polyether resins (such as polyvinyl ether), polyamide resins, fluorine resins, vinyl acetate/vinyl chloride copolymers, and modified polyolefins.
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be any of known and conventional pressure-sensitive adhesives, and examples thereof include acrylic pressure-sensitive adhesives, rubber pressure-sensitive adhesives (natural rubber-based, synthetic rubber-based, and mixtures thereof), silicone pressure-sensitive adhesives, polyester pressure-sensitive adhesives, urethane pressure-sensitive adhesives, polyether pressure-sensitive adhesives, polyamide pressure-sensitive adhesives, fluorine pressure-sensitive adhesives, and styrene pressure-sensitive adhesives, depending on the type of base polymer. Among them, an acrylic adhesive is preferable as an adhesive constituting the adhesive layer in terms of adhesion, weather resistance, cost, and ease of designing the adhesive. The binder may be used alone or in combination of two or more.
The acrylic adhesive contains an acrylic polymer as a base polymer. That is, the base polymer is preferably an acrylic polymer.
The acrylic polymer is a polymer containing an acrylic monomer (a monomer having a (meth) acryloyl group in a molecule) as a monomer component constituting the polymer. That is, the acrylic polymer contains a structural unit derived from an acrylic monomer. The acrylic polymer may be used alone or in combination of two or more. The acrylic polymer may contain only one kind of acrylic monomer as a monomer component, or may contain two or more kinds. In the present specification, "(meth) acrylic acid" means "acrylic acid" and/or "methacrylic acid" ("acrylic acid" or "methacrylic acid" either or both), and the other is the same.
The acrylic polymer is preferably a polymer having the largest content of structural units derived from (meth) acrylic esters in terms of mass ratio. Examples of the (meth) acrylate include hydrocarbon group-containing (meth) acrylates. Examples of the hydrocarbon group-containing (meth) acrylate include (meth) acrylic acid esters having an alicyclic hydrocarbon group such as alkyl (meth) acrylate and cycloalkyl (meth) acrylate having a linear or branched aliphatic hydrocarbon group, and (meth) acrylic acid esters having an aromatic hydrocarbon group such as aryl (meth) acrylate. The above-mentioned hydrocarbon group-containing (meth) acrylate may be used alone or in combination of two or more.
Examples of the alkyl (meth) acrylate include: methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, lauryl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, and the like.
The alkyl (meth) acrylate is particularly preferably an alkyl (meth) acrylate having a linear or branched aliphatic hydrocarbon group having 1 to 20 carbon atoms (preferably 2 to 12 carbon atoms, more preferably 2 to 4 carbon atoms). When the carbon number is within the above range, the storage stability tends to be more excellent.
In order to more suitably exhibit basic properties such as adhesiveness due to the alkyl (meth) acrylate, the proportion of the alkyl (meth) acrylate in the total monomer components constituting the acrylic polymer is preferably 30% by mass or more, more preferably 40% by mass or more, and still more preferably 45% by mass or more, relative to the total amount (100% by mass) of the total monomer components. The ratio is preferably 80% by mass or less, more preferably 70% by mass or less, and still more preferably 60% by mass or less, from the viewpoint of copolymerizing other monomer components to obtain the effect of the other monomer components.
Examples of the alicyclic hydrocarbon group-containing (meth) acrylate include: (meth) acrylic esters having a cyclic aliphatic hydrocarbon ring such as cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and cyclooctyl (meth) acrylate; (meth) acrylic esters having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth) acrylate; and (meth) acrylic esters having an aliphatic hydrocarbon ring having three or more rings, such as dicyclopentanoethyl (meth) acrylate, tricyclopenthyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2-adamantyl (meth) acrylate.
The proportion of the alicyclic hydrocarbon group-containing (meth) acrylate in the total monomer components constituting the acrylic polymer is preferably 0.6 mass% or more, more preferably 1 mass% or more, and still more preferably 2 mass% or more, based on the total amount (100 mass%) of the total monomer components. The proportion is preferably 20% by mass or less, more preferably 12% by mass or less.
Examples of the (meth) acrylic acid ester having an aromatic hydrocarbon group include phenyl (meth) acrylate and benzyl (meth) acrylate.
The proportion of the aromatic hydrocarbon group-containing (meth) acrylate in the total monomer components constituting the acrylic polymer is preferably less than 33 mass%, more preferably not more than 32 mass%, based on the total amount (100 mass%) of the total monomer components. The proportion may be 5% by mass or more, or 10% by mass or more.
The proportion of the hydrocarbon group-containing (meth) acrylate in the total monomer components constituting the acrylic polymer is preferably 60 mass% or more, more preferably 70 mass% or more, based on the total amount (100 mass%) of the total monomer components. The ratio is preferably 99.9 mass% or less, more preferably 94 mass% or less, and still more preferably 90 mass% or less, from the viewpoint that the effect of the other monomer component can be obtained by copolymerizing the other monomer component.
The acrylic polymer may contain structural units derived from other monomer components copolymerizable with the hydrocarbon group-containing (meth) acrylate for the purpose of improving cohesive force, heat resistance, and the like. Examples of the other monomer component include a polar group-containing monomer such as a hydroxyl group-containing monomer, a nitrogen atom-containing monomer, a carboxyl group-containing monomer, an acid anhydride monomer, a ketone group-containing monomer, an alkoxysilyl group-containing monomer, a glycidyl group-containing monomer, a sulfonic acid group-containing monomer, and a phosphoric acid group-containing monomer. The polar group-containing monomer is particularly preferably a hydroxyl group-containing monomer. The polar group-containing monomer may be used alone or in combination of two or more.
Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate.
Examples of the nitrogen atom-containing monomer include an amide group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, and a monomer having a nitrogen atom-containing ring. Examples of the amide group-containing monomer include (meth) acrylamide, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-hydroxymethyl propane (meth) acrylamide, N-methoxymethyl (meth) acrylamide, and N-butoxymethyl (meth) acrylamide. Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N-dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, and the like. Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile. Examples of the monomer having a nitrogen atom-containing ring include N-vinyl-2-pyrrolidone, N-methyl-vinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyridine, N-vinylpiperidine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N- (meth) acryloylmorpholine and the like.
Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the acid anhydride monomer include maleic anhydride and itaconic anhydride.
Examples of the ketone group-containing monomer include diacetone (meth) acrylamide, diacetone (meth) acrylate, vinylmethyl ketone, vinylethyl ketone, allyl acetoacetate, and vinyl acetoacetate.
Examples of the alkoxysilyl group-containing monomer include 3- (meth) acryloxypropyl trimethoxysilane, 3- (meth) acryloxypropyl triethoxysilane, 3- (meth) acryloxypropyl methyldimethoxysilane, and 3- (meth) acryloxypropyl methyldiethoxysilane.
Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and methyl glycidyl (meth) acrylate.
Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloxynaphthalene sulfonic acid.
Examples of the phosphate group-containing monomer include 2-hydroxyethyl acryloyl phosphate.
The total of the proportions of the polar group-containing monomers in the total monomer components (100 mass%) constituting the acrylic polymer is not particularly limited, but is preferably 0.1 mass% or more, more preferably 6 mass% or more, and still more preferably 10 mass% or more, from the viewpoint of better effects due to the use of the polar group-containing monomers. The total of the above proportions is preferably 40 mass% or less, more preferably 30 mass% or less.
Other monomers may be contained as the monomer component constituting the acrylic polymer. Examples of the other monomer include: vinyl ester monomers such as vinyl acetate, vinyl propionate and vinyl laurate; aromatic vinyl compounds such as styrene, substituted styrene (α -methylstyrene, etc.), and vinyl toluene; olefin monomers such as ethylene, propylene, isoprene, butadiene, and isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; alkoxy-containing monomers such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate; vinyl ether monomers such as methyl vinyl ether and ethyl vinyl ether. The other monomer components may be used alone or in combination of two or more.
Examples of the alkoxy group-containing monomer include alkoxy group-containing (meth) acrylates such as methoxymethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-methoxybutyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, and ethoxyethoxyethoxyethyl (meth) acrylate, and ethyl carbitol ((meth) acrylate), wherein 1 or more hydrogen atoms in the hydrocarbon group-containing (meth) acrylate are replaced with an alkoxy group.
The proportion of the other monomer in 100 mass% of the total amount of all the monomer components constituting the acrylic polymer may be, for example, 0.05 mass% or more, 0.5 mass% or more, 5 mass% or more, or 10 mass% or more. The proportion may be, for example, 20 mass% or less, 10 mass% or less, or 5 mass% or less, or may be substantially not included.
The acrylic polymer may contain a structural unit derived from the high refractive index monomer. As the high refractive index monomer, a monomer component having a high refractive index among the monomer components disclosed in the present specification may be used. Specific examples of the high refractive index monomer belonging to the acrylic monomer include m-phenoxybenzyl acrylate (refractive index: 1.566), 1-naphthylmethyl acrylate (refractive index: 1.595), ethoxylated o-phenylphenol acrylate (repeat number of oxyethylene units: 1, refractive index: 1.578), benzyl acrylate (refractive index (nD 20): 1.519, tg of homopolymer: 6 ℃), phenoxyethyl acrylate (refractive index (nD 20): 1.517), phenoxydiglycol acrylate (refractive index: 1.510), 6-acryloxymethyldinaphthiophene (6 MDNTA, refractive index: 1.75), 6-methacryloxymethyldinaphthiophene (6 MDNTMA, refractive index: 1.726), 5-acryloxyethyldinaphthiophene (5 EDNTA, refractive index: 1.786), 6-acryloxyethyldinaphthiophene (6 EDNTA, refractive index: 1.722), 6-vinyldinaphthiophene (6 VDNT, refractive index: 1.5657), 5-vinyldinaphthiophene (refractive index: VDNT), and the like. The high refractive index monomer may be used alone or in combination of two or more.
The proportion of the high refractive index monomer in 100 mass% of the total amount of all the monomer components constituting the acrylic polymer is preferably less than 33 mass%, more preferably 32 mass% or less, relative to the total amount (100 mass%) of all the monomer components. The proportion may be 5% by mass or more, or 10% by mass or more.
The acrylic polymer may contain structural units derived from a multifunctional (meth) acrylate copolymerizable with the monomer component constituting the acrylic polymer in order to form a crosslinked structure in the polymer skeleton. That is, the adhesive composition may contain the multifunctional (meth) acrylate. Examples of the polyfunctional (meth) acrylate include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. The polyfunctional monomer may be used alone or in combination of two or more.
In order to properly exhibit basic properties such as adhesiveness due to the hydrocarbon group-containing (meth) acrylate and adhesiveness to the optical semiconductor element, the content of the polyfunctional monomer is preferably 0.001 to 1 part by mass, more preferably 0.01 to 0.1 part by mass, relative to 100 parts by mass of the total amount of all monomer components constituting the acrylic polymer.
The acrylic polymer is obtained by polymerizing the various monomer components. The polymerization method is not particularly limited, and examples thereof include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, a polymerization method by irradiation with active energy rays (active energy ray polymerization method), and the like. The acrylic polymer obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.
In the polymerization of the monomer component, various general solvents can be used. Examples of the solvent include esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; organic solvents such as ketones including methyl ethyl ketone and methyl isobutyl ketone. The solvent may be used alone or in combination of two or more.
The polymerization initiator, chain transfer agent, emulsifier, etc. used in the radical polymerization of the monomer component are not particularly limited, and may be appropriately selected and used. The weight average molecular weight of the acrylic polymer can be controlled by the amount of the polymerization initiator, the amount of the chain transfer agent, and the reaction conditions, and the amount thereof to be used is appropriately adjusted depending on the kind of the polymerization initiator, the chain transfer agent, and the reaction conditions.
As the polymerization initiator used in the polymerization of the monomer component, a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), or the like can be used depending on the kind of polymerization reaction. The polymerization initiator may be used alone or in combination of two or more.
The thermal polymerization initiator is not particularly limited, and examples thereof include azo-based polymerization initiators, peroxide-based polymerization initiators, redox-based polymerization initiators, and the like. The amount of the thermal polymerization initiator to be used is preferably 1 part by mass or less, more preferably 0.005 to 1 part by mass, and still more preferably 0.02 to 0.5 part by mass, based on 100 parts by mass of the total amount of all the monomer components constituting the acrylic polymer.
Examples of the photopolymerization initiator include benzoin ether photopolymerization initiators, acetophenone photopolymerization initiators, α -ketol photopolymerization initiators, aromatic sulfonyl chloride photopolymerization initiators, photoactive oxime photopolymerization initiators, benzoin photopolymerization initiators, benzil photopolymerization initiators, benzophenone photopolymerization initiators, ketal photopolymerization initiators, thioxanthone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, and titanocene photopolymerization initiators. Among them, acetophenone photopolymerization initiators are preferable.
Examples of the acetophenone photopolymerization initiator include 2, 2-diethoxyacetophenone, 2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, 4-phenoxydichloroacetophenone, 4- (tert-butyl) dichloroacetophenone, 1- [4- (2-hydroxyethoxy) -phenyl ] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, and methoxyacetophenone.
The amount of the photopolymerization initiator to be used is preferably 0.005 to 1 part by mass, more preferably 0.01 to 0.7 part by mass, and still more preferably 0.18 to 0.5 part by mass, based on 100 parts by mass of the total amount of all the monomer components constituting the acrylic polymer. When the amount is 0.005 parts by mass or more, the molecular weight of the acrylic polymer tends to be easily controlled to be small, and the following property to the uneven structure tends to be more excellent.
The acrylic polymer may have a structural part derived from a crosslinking agent. In addition, the adhesive composition may contain a crosslinking agent. For example, the acrylic polymer can be crosslinked to further reduce the low molecular weight substance in the pressure-sensitive adhesive layer. In addition, the weight average molecular weight of the acrylic polymer can be increased. The crosslinking agent may be used alone or in combination of two or more.
Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, amine-based crosslinking agents, silicone-based crosslinking agents, and silane-based crosslinking agents.
Examples of the isocyanate-based crosslinking agent (polyfunctional isocyanate compound) include lower aliphatic polyisocyanates such as 1, 2-ethylene diisocyanate, 1, 4-butylene diisocyanate, and 1, 6-hexamethylene diisocyanate; alicyclic polyisocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated xylene diisocyanate; aromatic polyisocyanates such as 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 4' -diphenylmethane diisocyanate, and xylylene diisocyanate. Examples of the isocyanate-based crosslinking agent include trimethylolpropane/toluene diisocyanate adduct, trimethylolpropane/hexamethylene diisocyanate adduct, and trimethylolpropane/xylylene diisocyanate adduct.
The content of the crosslinking agent is not particularly limited, but is preferably 5 parts by mass or less, more preferably 0.001 to 5 parts by mass, and still more preferably 0.01 to 3 parts by mass, based on 100 parts by mass of the total amount of all the monomer components forming the acrylic polymer.
The light diffusing fine particles impart diffusing properties to the adhesive layer. Examples of the light diffusing fine particles include inorganic fine particles and polymer fine particles. Examples of the material of the inorganic fine particles include silica, calcium carbonate, aluminum hydroxide, magnesium hydroxide, clay, talc, and metal oxide. Examples of the material of the polymer microparticles include silicone resins, acrylic resins (including, for example, polymethyl methacrylate resins such as polymethyl methacrylate), polystyrene resins, polyurethane resins, melamine resins, polyethylene resins, and epoxy resins. The light diffusing fine particles may be used alone or in combination of two or more.
The polymer fine particles are preferably fine particles made of silicone resin. The inorganic fine particles are preferably fine particles made of metal oxide. The metal oxide is preferably titanium oxide or barium titanate, and more preferably titanium oxide. With such a configuration, the adhesive layer is more excellent in light diffusion property and further suppressed in luminance unevenness.
The shape of the light diffusing fine particles is not particularly limited, and may be, for example, spherical, flat, or irregular.
The average particle diameter of the light diffusing fine particles is preferably 0.1 μm or more, more preferably 0.15 μm or more, still more preferably 0.2 μm or more, and particularly preferably 0.25 μm or more from the viewpoint of imparting an appropriate light diffusing property. The average particle diameter of the light diffusing fine particles is preferably 12 μm or less, more preferably 10 μm or less, and even more preferably 8 μm or less, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image. The average particle diameter can be measured, for example, using a coulter counter.
The refractive index of the light diffusing fine particles is preferably 1.2 to 5, more preferably 1.25 to 4.5, still more preferably 1.3 to 4, and particularly preferably 1.35 to 3.
The content of the light diffusing fine particles is preferably 0.7 parts by mass or more, more preferably 3 parts by mass or more, and still more preferably 10 parts by mass or more, based on 100 parts by mass of the total amount of the base polymer, from the viewpoint of imparting an appropriate light diffusing property to the adhesive layer. The content of the light diffusing fine particles is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and even more preferably 35 parts by mass or less, based on 100 parts by mass of the total amount of the base polymer, from the viewpoint of preventing the haze value from becoming too high and displaying a high-definition image.
The content ratio (corresponding to X1) of the light diffusing fine particles in the pressure-sensitive adhesive layer is preferably 29 mass% or less, more preferably 25 mass% or less, relative to 100 mass% of the total amount of the pressure-sensitive adhesive layer. When the content is 29 mass% or less, the storage stability is further excellent. The content is preferably 3% by mass or more, more preferably 5% by mass or more. When the content is 3 mass% or more, the haze of the pressure-sensitive adhesive layer can be further improved.
The adhesive composition preferably contains a colorant. The colorant may be a dye or a pigment as long as it is soluble or dispersible in the adhesive layer. Dyes are preferred from the viewpoint of achieving low haze even when added in a small amount, and being easily and uniformly distributed without having precipitability like pigments. In addition, pigments are preferable in terms of high color rendering properties even when added in small amounts. When a pigment is used as the colorant, a pigment having low conductivity or no conductivity is preferable. The colorant may be used alone or in combination of two or more.
As the colorant, a black-based colorant is preferable. As the black colorant, known or customary colorants (pigments, dyes, etc.) for black color can be used, and examples thereof include: carbon black (furnace black, channel black, acetylene black, thermal black, lamp black, pine black, etc.), graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (nonmagnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, anthraquinone-based colorant, zirconium nitride, etc. Further, a colorant that functions as a black-based colorant may be used in combination with a colorant that exhibits a color other than black.
When the pressure-sensitive adhesive layer is a radiation-curable pressure-sensitive adhesive layer, the colorant is preferably a colorant that absorbs visible light and has a light transmittance at a wavelength at which the radiation-curable pressure-sensitive adhesive layer can be cured.
The content of the colorant in the pressure-sensitive adhesive layer is preferably 0.04 mass% or more, more preferably 0.1 mass% or more, and may be 0.2 mass% or more, or 0.4 mass% or more, relative to 100 mass% of the total amount of the pressure-sensitive adhesive layer, from the viewpoint of imparting an appropriate antireflection capability to the adherend. The content of the colorant is, for example, 10 mass% or less, preferably 5 mass% or less, more preferably 3 mass% or less, still more preferably 1 mass% or less, and may be 0.8 mass% or less. The content ratio may be appropriately set according to the type of the colorant, the color tone of the adhesive layer, the light transmittance, and the like. The colorant may be added to the composition as a solution or dispersion in a suitable solvent.
The adhesive composition may contain other components than the above components within a range that does not impair the effects of the present invention. Examples of the other components include a curing agent, a crosslinking accelerator, a tackifying resin (rosin derivative, polyterpene resin, petroleum resin, oil-soluble phenol, etc.), an anti-aging agent, a filler (metal powder, organic filler, inorganic filler, etc.), an antioxidant, a plasticizer, a softener, a surfactant, an antistatic agent, a surface lubricant, a leveling agent, a light stabilizer, an ultraviolet absorber, a polymerization inhibitor, a particulate matter, a foil-like matter, and the like. The other components may be used alone or in combination of two or more.
[ Adhesive layer ]
The adhesive composition described above may be used to form an adhesive layer. The adhesive layer formed using the adhesive composition of the present invention is sometimes referred to as "the adhesive layer of the present invention". The adhesive layer can be produced, for example, as follows: the pressure-sensitive adhesive composition is prepared by applying the pressure-sensitive adhesive composition to a release treated surface of a release liner and a substrate to form a pressure-sensitive adhesive composition layer, and then curing the pressure-sensitive adhesive composition layer by polymerization by desolvation under heating and irradiation with radiation.
The pressure-sensitive adhesive layer may be a pressure-sensitive adhesive layer having a property of being cured by irradiation with radiation (radiation-curable pressure-sensitive adhesive layer), or may be a pressure-sensitive adhesive layer not having a property of being cured by irradiation with radiation (radiation-non-curable pressure-sensitive adhesive layer). Examples of the radiation include electron beam, ultraviolet ray, α ray, β ray, γ ray, and X ray.
The haze value (initial haze value) of the pressure-sensitive adhesive layer is preferably 61% or more, more preferably 70% or more, still more preferably 80% or more, particularly preferably 90% or more, and may be 95% or more, 97% or more, and may be in the vicinity of 99.9%. When the haze value is 61% or more, uneven brightness of light transmitted through the pressure-sensitive adhesive layer can be suppressed when the pressure-sensitive adhesive layer is attached to an adherend. The upper limit of the haze value is not particularly limited, and may be 100%.
The total light transmittance of the pressure-sensitive adhesive layer is 69% or less, preferably 60% or less, more preferably 50% or less, still more preferably 40% or less, still more preferably 30% or less. The total light transmittance is preferably 0.5% or more, more preferably 1% or more, further preferably 1.5% or more, further preferably 2% or more, further preferably 2.5% or more, and particularly preferably 3% or more, from the viewpoint of ensuring light transmittance.
The haze value and the total light transmittance are each a single-layer value, and can be measured by a method defined in JIS K7136 and JIS K7361-1, and can be controlled by the type of the pressure-sensitive adhesive layer, the thickness, the colorant, the type of the light-diffusing fine particles, the blending amount, and the like.
The curing rate of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 150% or less, more preferably 140% or less, further preferably 130% or less, particularly preferably 120% or less, from the viewpoint of excellent storage stability. The curing rate is preferably 80% or more, more preferably 90% or more, and may be 95% or more, or 100% or more. The above curing rate was calculated as the ratio [ residual stress value (after storage)/residual stress value (initial) ×100] of the residual stress value "residual stress value (after storage)" of the adhesive layer stored at 70 ℃ for 7 days when the initial residual stress value "residual stress value (initial)" of the adhesive layer was set to 100.
The thickness of the pressure-sensitive adhesive layer is preferably 5 to 100. Mu.m, more preferably 10 to 80. Mu.m, and still more preferably 20 to 70. Mu.m. When the thickness is 5 μm or more, the antireflection property and the light diffusion function are more excellent. When the thickness is 100 μm or less, the light transmittance is more easily ensured. The pressure-sensitive adhesive layer of the present invention can be made thinner to 100 μm or less while having both functions of the conventional colored layer and the light diffusion functional layer.
[ Laminate sheet ]
The adhesive layer of the present invention may be laminated with other layers to form a laminate. The laminate sheet includes a bonding portion including at least the adhesive layer of the present invention. Examples of the other layer include an adhesive layer other than the adhesive layer of the present invention, a resin layer, a base material portion described later, a layer having antiglare properties, a layer having antireflection properties, and the like. The laminate sheet may be provided with a plurality of adhesive layers of the present invention directly or indirectly. In this case, the plurality of adhesive layers of the present invention may be the same layer in thickness, composition, physical properties, or the like, or may be different layers.
The other layer may be a non-diffusion functional layer. For example, the adhesive layer of the present invention may be laminated with a non-diffusion functional layer to obtain a laminated sheet. In this case, the laminate sheet includes a bonding portion including at least the adhesive layer and the non-diffusion functional layer. The laminate may further include other layers.
(Non-diffusion functional layer)
The non-diffusion functional layer is a non-colored adhesive layer which does not have a function of diffusing light.
The content of the colorant in the non-diffusion functional layer is preferably less than 0.2 mass%, more preferably less than 0.1 mass%, still more preferably less than 0.05 mass%, and may be less than 0.01 mass% or less than 0.005 mass% relative to 100 mass% of the total non-diffusion functional layer.
The haze value (initial haze value) of the non-diffusion functional layer is not particularly limited, but is preferably less than 30%, more preferably 10% or less, further preferably 5% or less, particularly preferably 1% or less, and may be 0.5% or less. The lower limit of the haze value of the non-diffusion functional layer is not particularly limited.
The total light transmittance of the non-diffusion functional layer is not particularly limited, but is preferably 60% or more, more preferably 70% or more, further preferably 80% or more, and particularly preferably 90% or more. The upper limit of the total light transmittance of the non-diffusion functional layer is not particularly limited, and may be less than 100%, or 99.9% or less, or 99% or less.
The haze value and the total light transmittance of the non-diffusion functional layer are each a single layer, and can be measured by a method defined in JIS K7136 and JIS K7361-1, and can be controlled by the type, thickness, and the like of the non-diffusion functional layer.
The content of the colorant and/or the light diffusing fine particles in the non-diffusion functional layer is preferably less than 0.01 parts by mass, more preferably less than 0.005 parts by mass, relative to 100 parts by mass of the resin constituting the non-diffusion functional layer, from the viewpoint of making the brightness of the image display device excellent.
The thickness of the non-diffusion functional layer is, for example, 5 to 480. Mu.m, preferably 5 to 100. Mu.m, more preferably 10 to 80. Mu.m, still more preferably 20 to 70. Mu.m. When the thickness is 5 μm or more, the sealing property of the optical semiconductor element becomes more excellent. When the thickness is 480 μm or less, the luminance of the optical semiconductor element at the time of light emission can be more easily ensured.
The pressure-sensitive adhesive for forming the non-diffusion functional layer may be the one exemplified and described as the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer of the present invention.
The haze value (initial haze value) of the adhesive portion is not particularly limited, but is preferably 90% or more, more preferably 95% or more, from the viewpoint of more excellent effect of suppressing luminance unevenness and design property. The upper limit of the haze value is not particularly limited.
The total light transmittance of the adhesive portion is not particularly limited, but is preferably 69% or less, more preferably 60% or less, further preferably 50% or less, further preferably 40% or less, particularly preferably 30% or less, from the viewpoint of further improving the function of preventing reflection of metal wiring or the like and further improving contrast. The total light transmittance is preferably 0.5% or more from the viewpoint of securing brightness.
The haze value and the total light transmittance can be measured by the methods defined in JIS K7136 and JIS K7361-1, respectively, and can be controlled by the lamination order, type, thickness, and the like of the layers constituting the adhesive portion.
The adhesive layers (the adhesive layer, the non-diffusion functional layer, and the like) constituting the adhesive portion may be a single layer or may be a plurality of layers having the same or different compositions within the adhesive portion. When each layer includes a plurality of layers, the plurality of layers may be stacked in contact with each other or may be stacked in isolation (for example, 2 adhesive layers of the present invention are stacked via 1 non-diffusion functional layer).
The adhesive portion preferably includes an adhesive layer and a non-diffusion functional layer according to the present invention in this order from the optical semiconductor element side when the optical semiconductor element is sealed. That is, the adhesive portion preferably includes the adhesive layer and the non-diffusion functional layer of the present invention in this order from the optical semiconductor element side when the optical semiconductor element is sealed.
The adhesive portion may have a single-layer structure including a single layer of the adhesive layer of the present invention or a laminated structure including the adhesive layer of the present invention. The laminated structure of the adhesive portion includes: a structure consisting of 2 layers of the adhesive layer of the present invention; the structure (in different orders) of the adhesive layer of the invention consisting of 2 layers, 1 layer being the adhesive layer of the invention, and the other layer being the adhesive layer, the coloring layer, the diffusion function layer or the non-diffusion function layer of the invention; the adhesive layer of the present invention is composed of 3 layers, 1 layer is the adhesive layer of the present invention, and the other 2 layers are the structures (different in order) of the adhesive layer, the coloring layer, the diffusion functional layer or the non-diffusion functional layer of the present invention, respectively; the adhesive layer of the present invention is composed of 4 layers, 1 layer is an adhesive layer of the present invention, and the other 3 layers are the structures (different orders) of the adhesive layer, the colored layer, the diffusion functional layer, or the non-diffusion functional layer of the present invention, respectively. More specifically, for example, [ the adhesive layer of the present invention ], [ the adhesive layer of the present invention/the non-diffusion functional layer ], [ the adhesive layer of the present invention/the non-diffusion functional layer/the diffusion functional layer ] (the above is in order from the optical semiconductor element side), and the like are cited.
The thickness of the adhesive portion is, for example, 500 μm or less, preferably 400 μm or less, and more preferably 300 μm or less. When the thickness is 500 μm or less, the thickness of the laminate sheet becomes thinner. The thickness of the adhesive portion is, for example, 100 μm or more, preferably 120 μm or more, and more preferably 150 μm or more. When the thickness is 100 μm or more, the sealing property of the optical semiconductor element becomes more excellent.
(Base material portion)
The adhesive portion may be provided on at least one surface of the base material portion. That is, the laminate sheet may include a base material portion and an adhesive portion provided on at least one surface of the base material portion. The base material portion may be a single layer, or may be the same or different in composition, thickness, or the like. When the base material portion has a plurality of layers, the layers may be bonded by other layers such as an adhesive layer. The base layer used in the base portion is a portion to be attached to the adherend together with the adhesive portion, and is a release liner that is peeled off at the time of use (at the time of attachment) of the laminate sheet, and is not included in the "base portion" merely as a surface protective film for protecting the surface of the base portion.
Examples of the substrate layer constituting the substrate portion include glass, a plastic substrate (particularly, a plastic film), and the like. Examples of the resin constituting the plastic base material include polyolefin resins such as low-density polyethylene, linear low-density polyethylene, medium-density polyethylene, high-density polyethylene, ultra-low-density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homo-polypropylene, polybutene, polymethylpentene, ionomer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-propylene copolymer, cyclic olefin polymer, ethylene-butene copolymer, and ethylene-hexene copolymer; a polyurethane; polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate, polybutylene terephthalate (PBT), and the like; a polycarbonate; polyimide resin; polyether ether ketone; a polyetherimide; polyamides such as aromatic polyamides and wholly aromatic polyamides; polyphenylene sulfide; a fluororesin; polyvinyl chloride; polyvinylidene chloride; cellulose resins such as cellulose Triacetate (TAC); a silicone resin; acrylic resins such as polymethyl methacrylate (PMMA); polysulfone; polyarylate; polyvinyl acetate, and the like. The resin may be used alone or in combination of two or more. The base material layer may be various optical films such as an Antireflection (AR) film, a polarizing plate, and a retardation plate.
The thickness of the plastic film is preferably 20 to 300. Mu.m, more preferably 40 to 250. Mu.m. When the thickness is 20 μm or more, the supporting property and handling property of the laminate are further improved. When the thickness is 300 μm or less, the laminated sheet can be made thinner.
The surface of the base material portion on the side having the adhesive portion may be subjected to physical treatments such as corona discharge treatment, plasma treatment, sand mat treatment, ozone exposure treatment, flame exposure treatment, high-voltage electric shock exposure treatment, and ionizing radiation treatment for the purpose of improving adhesion to the adhesive portion, retention, and the like; chemical treatments such as chromic acid treatment; surface treatment such as easy adhesion treatment by a coating agent (primer). The surface treatment for improving the adhesion is preferably performed on the entire surface of the base material portion on the side of the adhesive portion.
The thickness of the base material portion is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of excellent functions as a support and scratch resistance of the surface. The thickness of the base material portion is preferably 300 μm or less, more preferably 250 μm or less, from the viewpoint of further excellent transparency.
< Laminate >
The laminate sheet is preferably an optical semiconductor element sealing sheet. In the present specification, the optical semiconductor element sealing sheet refers to a sheet for sealing 1 or more optical semiconductor elements disposed on a substrate. In the present specification, the term "sealing the optical semiconductor element" means embedding at least a part of the optical semiconductor element in the laminate sheet (particularly, in the adhesive portion) or following and coating the laminate sheet (particularly, in the adhesive portion). The laminate sheet (particularly, the adhesive portion) has flexibility that enables at least a part of the optical semiconductor element to be embedded therein or that enables the laminate sheet (particularly, the adhesive portion) to follow and cover the optical semiconductor element.
When the laminate sheet includes the base material portion, if the laminate sheet includes the base material portion on the side of the adhesive portion opposite to the optical semiconductor element side, the surface of the adhesive portion can be flattened, and therefore diffuse reflection of light is less likely to occur, and the appearance of the image display device is improved at both the time of turning off the light and the time of emitting the light. Further, by forming an antiglare layer and an antireflection layer described later on the base material portion, antiglare property and antireflection property can be provided to the image display device.
The laminate sheet may have a layer having antiglare properties and/or antireflection properties. With such a configuration, gloss and reflection of light can be suppressed when the optical semiconductor element is sealed, and the appearance can be improved. The antiglare layer may be an antiglare treatment layer (ANTIGLARE LAYER). The antireflective layer may be an antireflective treatment layer. The antiglare treatment and the antireflection treatment may be carried out by known or conventional methods, respectively. The antiglare layer and the antireflection layer may be the same layer or may be different from each other. The antiglare and/or antireflection layer may be provided in one layer or two or more layers. The laminate sheet preferably includes a layer having antiglare property and/or antireflection property on one of the outermost surfaces of the laminate sheet.
In the state where the optical semiconductor element is sealed with the laminate sheet, the pressure-sensitive adhesive layer of the present invention is preferably flat (planar) with the surface on the opposite side to the side where the optical semiconductor element is sealed. In this case, diffuse reflection of external light is less likely to occur on the surface of the laminate sheet in a state where the optical semiconductor element is sealed, and the appearance of the image display device is improved at both the time of turning off the light and the time of emitting the light.
The haze value (initial haze value) of the laminate sheet is not particularly limited, but is preferably 80% or more, more preferably 85% or more, still more preferably 90% or more, particularly preferably 95% or more, from the viewpoint of more excellent effect of suppressing luminance unevenness and design. The upper limit of the haze value is not particularly limited.
The total light transmittance of the laminate is not particularly limited, but is preferably 40% or less, more preferably 30% or less, and still more preferably 20% or less, from the viewpoint of further improving the function of preventing reflection of metal wiring or the like and the contrast. The total light transmittance is preferably 0.5% or more from the viewpoint of securing brightness.
The haze value and the total light transmittance can be measured by the methods defined in JIS K7136 and JIS K7361-1, and can be controlled by the lamination order, type, thickness, and the like of the layers constituting the laminate sheet, for example, the adhesive portion and the base material portion.
The thickness of the laminate sheet (for example, the optical semiconductor element sealing sheet) is not particularly limited, but is preferably 500 μm or less, more preferably 400 μm or less, and still more preferably 300 μm or less. The pressure-sensitive adhesive layer of the present invention has both functions of the conventional colored layer and the light diffusion functional layer, and therefore can be thinner than the conventional laminate sheet having both the colored layer and the light diffusion functional layer. The thickness is, for example, 10 μm or more.
Fig. 1 and 2 are cross-sectional views showing an embodiment of a laminate sheet having an adhesive layer of the present invention. As shown in fig. 1 and 2, the laminate sheet 1 can be used for sealing 1 or more optical semiconductor elements arranged on a substrate, and includes a base material portion 4 and an adhesive portion 2 formed on the base material portion 4. The base material portion 4 is composed of the base material film 41 and the functional layer 42 which is a surface treatment layer, but may be composed of the base material film 41 without the functional layer 42.
In the laminate sheet 1 shown in fig. 1, the adhesive portion 2 is formed of a single layer of the adhesive layer 21 of the present invention. A release liner 3 is attached to one surface of the pressure-sensitive adhesive layer 21 of the present invention, and a base material portion 4 is attached to the other surface.
In the laminated sheet 1 shown in fig. 2, the adhesive portion 2 is formed of a laminate of the adhesive layer 21 and the non-diffusion functional layer 22 of the present invention. The non-diffusion functional layer 22 is directly laminated to the adhesive layer 21 of the present invention. The release liner 3 is attached to the adhesive layer 21 of the present invention, and the base material portion 4 is attached to the non-diffusion functional layer 22.
In fig. 1 and 2, the functional layer 42 is a layer not included in the adhesive portion, and examples thereof include layers capable of imparting various functions to the laminate. Examples of the functional layer include a layer including a surface treatment layer. With such a configuration, the laminated sheet in which the functional layer including the surface treatment layer is laminated is excellent in light diffusion property and light extraction efficiency. Examples of the surface treatment layer include an antiglare treatment layer (ANTIGLARE LAYER), an antireflection treatment layer, and a hard coat treatment layer. The functional layer may be laminated on the adhesive portion in the laminate sheet, or may be laminated on the base material portion when the base material portion is provided, preferably on the base material portion, and preferably on the side of the base material portion opposite to the side provided with the adhesive portion.
[ Release liner ]
The adhesive portion may be formed on a release treated surface of the release liner. When the base material portion is not provided, both surfaces of the adhesive portion may be the sides in contact with the release liner. The release liner is used as a protective material for the laminate sheet, and is peeled off when attached to an adherend such as an optical semiconductor element. It should be noted that a release liner may not be necessary.
The release liner is a component for protecting the surface of the laminate sheet, and is peeled off from the laminate sheet when the laminate sheet is bonded to an adherend.
Examples of the release liner include: polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, plastic film obtained by surface coating with a release agent such as a fluorine-based release agent or a long-chain alkyl acrylate-based release agent, paper, and the like.
The thickness of the release liner is, for example, 10 to 200. Mu.m, preferably 15 to 150. Mu.m, more preferably 20 to 100. Mu.m. When the thickness is 10 μm or more, the release liner is less likely to be broken by a dicing mark during processing. When the thickness is 200 μm or less, the release liner is more easily peeled from the laminate sheet at the time of use.
[ Method for producing laminate sheet ]
An embodiment of the method for producing a laminated sheet described above will be described. For example, with respect to the laminate sheet 1 shown in fig. 1, the adhesive layer 21 of the present invention sandwiched by the release treated surfaces of 2 release liners was produced. One release liner attached to the adhesive layer 21 of the present invention is the release liner 3. Next, one release liner (not the release liner of the release liner 3) attached to the adhesive layer 21 of the present invention is peeled off to expose the surface of the adhesive layer 21 of the present invention, and the exposed surface is attached to the base material portion 4. Thus, the laminate sheet 1 shown in fig. 1 in which the pressure-sensitive adhesive layer 21 and the release liner 3 of the present invention are laminated in this order on the base material portion 4 can be produced.
For the laminate 1 shown in fig. 2, for example, the pressure-sensitive adhesive layer 21 and the non-diffusion functional layer 22 of the present invention each sandwiched between release treated surfaces of 2 release liners are prepared. One release liner attached to the adhesive layer 21 of the present invention is the release liner 3. Then, one release liner attached to the non-diffusion functional layer 22 is peeled off to expose the surface of the non-diffusion functional layer 22, and the exposed surface is attached to the base material portion 4. Thereafter, one release liner (not the release liner of the release liner 3) attached to the pressure-sensitive adhesive layer 21 of the present invention is peeled off, and the exposed surface of the pressure-sensitive adhesive layer 21 of the present invention is bonded to the surface of the non-diffusion functional layer 22 exposed by peeling off the release liner on the surface of the non-diffusion functional layer 22. The lamination of the various layers may be performed using a known roll or laminator. Thus, the light laminate sheet 1 shown in fig. 2 in which the non-diffusion functional layer 22, the pressure-sensitive adhesive layer 21 of the present invention, and the release liner 3 are laminated in this order on the base material portion 4 can be produced.
[ Optical semiconductor device ]
An optical semiconductor device such as an image display device can be manufactured using the above laminate. An optical semiconductor device manufactured using the laminate sheet includes: a substrate, an optical semiconductor element arranged on the substrate, and a cured product obtained by curing the laminate sheet or the sheet for sealing the optical semiconductor element. The cured product is a cured product obtained by curing the radiation-curable adhesive layer by irradiation with radiation when the laminate sheet includes the radiation-curable adhesive layer.
Examples of the optical semiconductor element include Light Emitting Diodes (LEDs) such as blue light emitting diodes, green light emitting diodes, red light emitting diodes, and ultraviolet light emitting diodes.
In the above-described optical semiconductor device, since the laminate sheet has excellent following properties for irregularities when the optical semiconductor element is a convex portion and gaps between the plurality of optical semiconductor elements are concave portions, the optical semiconductor element has excellent following properties and embedding properties, and therefore, it is preferable to seal the plurality of optical semiconductor elements at once.
The height of the optical semiconductor element on the substrate (the height from the substrate surface to the end on the front surface side of the optical semiconductor element) is preferably 500 μm or less. When the height is 500 μm or less, the adhesive portion has more excellent following property to the concave-convex shape.
Fig. 3 shows an embodiment of an optical semiconductor device using the laminate sheet 1 shown in fig. 1. The optical semiconductor device 10 shown in fig. 3 includes: the semiconductor device includes a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, a sealing resin layer 7 sealing the optical semiconductor elements 6, and a base material portion 4 laminated on the sealing resin layer 7. The plurality of optical semiconductor elements 6 are collectively sealed by the sealing resin layer 7. The sealing resin layer 7 is formed of a single layer of the diffusion function coloring layer 71. The diffusion function coloring layer 71 adheres to the optical semiconductor element 6 and the substrate 5 following the concave-convex shape formed by the plurality of optical semiconductor elements 6, and is embedded in the optical semiconductor element 6. The diffusion functional coloring layer 71 follows the concave-convex shape, and has a concave-convex shape at the interface on the optical semiconductor element 6 side and a flat interface at the other interface.
Fig. 4 shows an embodiment of an optical semiconductor device using the laminate sheet 1 shown in fig. 2. The optical semiconductor device 10 shown in fig. 4 includes: the semiconductor device includes a substrate 5, a plurality of optical semiconductor elements 6 arranged on one surface of the substrate 5, a sealing resin layer 7 sealing the optical semiconductor elements 6, and a base material portion 4 laminated on the sealing resin layer 7. The plurality of optical semiconductor elements 6 are collectively sealed by the sealing resin layer 7. The sealing resin layer 7 is formed by laminating a diffusion function coloring layer 71 and a non-diffusion function layer 72. The diffusion function coloring layer 71 adheres to the optical semiconductor element 6 and the substrate 5 following the concave-convex shape formed by the plurality of optical semiconductor elements 6, and is embedded in the optical semiconductor element 6. The diffusion functional coloring layer 71 follows the concave-convex shape, and has a concave-convex shape at the interface on the optical semiconductor element 6 side and a flat interface at the other interface.
In the optical semiconductor device 10 shown in fig. 4, the optical semiconductor element 6 is sealed so as to be entirely embedded in the diffusion function colored layer 71, and is indirectly sealed with the non-diffusion function layer 72. That is, the optical semiconductor element 6 is sealed with the sealing resin layer 7 including the laminate of the diffusion function coloring layer 71 and the non-diffusion function layer 72. The optical semiconductor device is not limited to this, and may be, for example, the following: as shown in fig. 5, the optical semiconductor element 6 is sealed so as to be entirely embedded in the diffusion functional coloring layer 71 and the non-diffusion functional layer 72.
Each of the optical semiconductor devices may be tiled. That is, the optical semiconductor device may be a plurality of optical semiconductor devices arranged in a tile shape in the planar direction.
The image display device preferably includes a self-luminous display device. Further, the above-described self-luminous display device can be combined with a display panel as needed to produce an image display device. The optical semiconductor element in this case is an LED element. Examples of the self-luminous display device include an LED display, a backlight, and an organic electroluminescence (organic EL) display device. The backlight is particularly preferably a full-surface direct type backlight. The backlight includes, for example, a laminate including the substrate and a plurality of optical semiconductor elements disposed on the substrate as at least a part of a constituent member. For example, in the self-luminous display device, a metal wiring layer for transmitting a light emission control signal to each LED element is laminated on the substrate. The LED elements that emit light of red (R), green (G), and blue (B) are alternately arranged on the substrate with a metal wiring layer interposed therebetween. The metal wiring layer is made of a metal such as copper, and the light emission degree of each LED element is adjusted to display each color.
The laminate sheet can be used for an optical semiconductor device for use in bending, for example, an optical semiconductor device having a bendable image display device (flexible display) (particularly, a foldable image display device (foldable display)). Specifically, the present invention can be used for a foldable backlight, a foldable self-luminous display device, and the like.
The optical semiconductor element of the laminate is excellent in following property and embedding property, and therefore, can be preferably used both when the optical semiconductor device is a mini LED display device and when the optical semiconductor device is a micro LED display device.
[ Method for manufacturing optical semiconductor device ]
The optical semiconductor device can be manufactured by, for example, bonding the laminate to a substrate on which the optical semiconductor element is arranged, sealing the optical semiconductor element with an adhesive portion, and curing the laminate as necessary.
(Sealing Process)
The method for manufacturing an optical semiconductor device using the laminate sheet includes a sealing step of bonding the laminate sheet to a substrate on which optical semiconductor elements are arranged and sealing the optical semiconductor elements by an adhesive portion. Specifically, in the sealing step, the release liner is peeled off from the laminate sheet to expose the adhesive portion. Then, an adhesive surface, which is an exposed surface of the laminate sheet, is bonded to a substrate surface on which optical semiconductor elements are arranged, the substrate surface including a laminate (optical member, etc.) of the optical semiconductor elements (preferably, a plurality of optical semiconductor elements) arranged on the substrate, and when the plurality of optical semiconductor elements are arranged, the laminate is arranged so that the adhesive portion fills gaps between the plurality of optical semiconductor elements, and the plurality of optical semiconductor elements are sealed together. Specifically, the pressure-sensitive adhesive layer 21 of the present invention, which is exposed by peeling the release liner 3 from the laminate sheet 1 shown in fig. 1 or 2, is disposed so as to face the surface of the substrate 5 on which the optical semiconductor element 6 is disposed, and the laminate sheet 1 is bonded to the surface of the substrate 5 on which the optical semiconductor element 6 is disposed, so that the optical semiconductor element 6 is embedded in the pressure-sensitive adhesive portion 2.
The temperature at the time of the above-mentioned bonding is, for example, in the range of room temperature to 110 ℃. In addition, the pressure may be reduced or increased during the bonding. By the pressure reduction or the pressure increase, formation of a void between the adhesive portion and the substrate or the optical semiconductor element can be suppressed. In the sealing step, it is preferable that the laminate sheet is bonded under reduced pressure and then pressurized. The pressure at the time of depressurization is, for example, 1to 100Pa, and the depressurization time is, for example, 5 to 600 seconds. The pressure at the time of pressurization is, for example, 0.05 to 0.5MPa, and the pressurization time is, for example, 5 to 600 seconds.
(Radiation irradiation step)
When the adhesive portion includes a radiation curable adhesive layer, the manufacturing method may further include a radiation irradiation step of: and irradiating a laminate including the substrate, the optical semiconductor element disposed on the substrate, and the laminate sheet sealing the optical semiconductor element with radiation, and curing the radiation-curable adhesive layer to form a cured layer. Examples of the radiation include electron beam, ultraviolet ray, α ray, β ray, γ ray, and X ray, as described above. Among them, ultraviolet rays are preferable. The temperature at the time of irradiation with the radiation is, for example, in the range of room temperature to 100 ℃, and the irradiation time is, for example, 1 minute to 1 hour.
(Cutting step)
The above-described manufacturing method may further include the following dicing step: cutting a laminate including the substrate, the optical semiconductor element disposed on the substrate, and the laminate sheet sealing the optical semiconductor element. The laminate may be subjected to the radiation irradiation step. When the laminate includes a cured product layer obtained by curing the radiation-curable adhesive layer by irradiation with the radiation, the cured product layer of the laminate and the side end portions of the substrate are cut and removed in the cutting step. This makes it possible to expose the surface of the cured product layer, which is sufficiently cured and has low adhesion, on the side surface. The cutting may be performed by a known or conventional method, for example, by a method using a cutter or laser irradiation.
(Tiling step)
The above manufacturing method may further include a tiling step of: the plurality of optical semiconductor devices obtained in the dicing step are arranged so as to be in contact with each other in the planar direction. In the tiling step, the plurality of laminated bodies obtained in the dicing step are aligned so as to be in contact with each other in the planar direction, and are tiled. Thus, 1 large image display device can be manufactured.
As described above, an optical semiconductor device can be manufactured. When the adhesive portion 2 does not have a radiation curable adhesive layer in the laminate sheet 1, the adhesive portion 2 becomes the sealing resin layer 7 in the optical semiconductor device 10. On the other hand, when the adhesive portion 2 of the laminate sheet 1 has a radiation curable adhesive layer, for example, when the adhesive layer 21 of the present invention is a radiation curable adhesive layer, the diffusion functional colored layer 71 is formed by curing the adhesive layer 21 of the present invention, and the sealing resin layer 7 is formed.
The adhesive composition of the present invention can produce an adhesive layer which has excellent anti-reflection properties, a high haze value, excellent storage stability, and suppressed turbidity when adhered to an adherend. Therefore, the laminate sheet provided with the adhesive layer is excellent in antireflection and light diffusion properties when used to seal an optical semiconductor element. Further, the laminate is excellent in storage stability, and is excellent in the following property of the irregularities when the laminate is bonded to an optical semiconductor element and the curability thereof when post-cured, and excellent in the sealing property of the optical semiconductor element. Further, since turbidity is suppressed, light extraction efficiency is excellent.
Examples
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The unit of the content of each component in the adhesive composition shown in table 1 represents relative "parts by mass".
Production example 1
(Preparation of acrylic prepolymer)
67 Parts by mass of Butyl Acrylate (BA), 14 parts by mass of cyclohexyl acrylate (CHA, trade name "viscoat #155", manufactured by Osaka organic chemical Co., ltd.), 19 parts by mass of 4-hydroxybutyl acrylate (4-HBA), 0.09 parts by mass of a photopolymerization initiator (trade name "omnirad 184", manufactured by IGM Co., ltd.), and 0.09 parts by mass of a photopolymerization initiator (trade name "omnirad 651", manufactured by IGM Co., ltd.) were charged into a detachable flask equipped with a thermometer, a stirrer, a reflux condenser, and nitrogen was circulated while stirring for about 1 hour. Thereafter, UVA was irradiated at 5mW/cm 2 to polymerize the resultant, and the resultant was adjusted so that the reaction rate was 5 to 15%, thereby obtaining an acrylic prepolymer solution.
Example 1
(Preparation of adhesive composition)
To 100 parts by mass of the acrylic prepolymer solution obtained in production example 1 were added 9 parts by mass of 2-hydroxyethyl acrylate (HEA), 8 parts by mass of 4-hydroxybutyl acrylate (4-HBA), 0.02 part by mass of dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by Japanese chemical Co., ltd.) as a polyfunctional monomer, 0.35 part by mass of 3-glycidoxypropyl trimethoxysilane (silane coupling agent), and 0.3 part by mass of a photopolymerization initiator (trade name "omnirad 651", manufactured by IGM Co., ltd.) to prepare a photopolymerizable adhesive composition solution.
In the photopolymerizable adhesive composition solution obtained in the above, light diffusing fine particles (trade name "tospearl", manufactured by Momentive Performance Materials inc. Silicone resin having a refractive index of 1.42 and an average particle diameter of 4.5 μm), benzyl acrylate (BzA, refractive index of 1.519), butyl Acrylate (BA), dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by japan chemical company), 4-hydroxybutyl acrylate (4-HBA), a 20% dispersion of a BLACK pigment (trade name "9256BLACK", manufactured by TOKUSHIKI co., ltd, components other than the pigment being alkyl acrylate and a dispersant), and a photopolymerization initiator (trade name "omnirad 651", manufactured by IGM company) were added in the mass ratio shown in table 1, and stirred to prepare an adhesive composition.
(Preparation of adhesive layer)
The adhesive composition was applied to a release-treated surface of a release liner (trade name "MRE38", manufactured by Mitsubishi chemical corporation, a thickness of 38 μm) and a resin composition layer was formed on the release-treated surface of the polyethylene terephthalate film, and then the release-treated surface of the release liner (trade name "MRF38", manufactured by Mitsubishi chemical corporation) was also bonded to the resin composition layer. Next, polymerization was carried out by irradiating ultraviolet rays with illuminance of 5mW/cm 2 and cumulative light quantity of 1300mJ/cm 2 using a black light lamp (trade name "FL15BL", toshiba Co., ltd.) to prepare an adhesive layer (thickness: 50 μm) as a cured product of the adhesive composition. The illuminance of the black light lamp was measured by an industrial UV detector (manufactured by Topcon corporation under the trade name "UVR-T1" and light-receiving unit model "UD-T36") having a peak sensitivity wavelength of about 350 nm.
Examples 2 to 8 and comparative examples 1 to 3
An adhesive composition and an adhesive layer were produced in the same manner as in example 1, except that the components were added in the mass ratios shown in table 1.
< Evaluation >
The adhesive compositions, adhesive layers, and laminates obtained in examples and comparative examples were evaluated as follows. The results are shown in Table 1.
(1) Total light transmittance
The release liners on one side were peeled off from the adhesive layers (in a form sandwiched by 2 release liners) produced in examples and comparative examples, and the exposed surfaces of the adhesive layers were bonded to glass plates (glass slides, product number "S-9112", manufactured by sonlano industrial Co., ltd.). Then, the other release liner was peeled off to prepare a measurement sample having a layer structure of [ glass plate/adhesive layer ]. For the above measurement samples, total light transmittance was measured by a haze meter (device name "HM-150", manufactured by color technology research, inc.). Measurement light is incident from the adhesive layer side, and measurement is performed.
(2) Haze value
For the measurement sample prepared for measuring the total light transmittance, the total light transmittance and the diffuse light transmittance were measured by a haze meter (device name "HM-150", manufactured by color technology research, inc.). Then, the haze value of the measurement sample was obtained by the expression of "diffuse transmittance/total transmittance×100", and was used as an initial haze value. Measurement light is incident from the adhesive layer side, and measurement is performed.
(3) Cure rate
The adhesive layer was cut into an arbitrary size suitable for measurement, and the release liner on one side was peeled off and wound into a tube from the end, thereby producing a cylindrical measurement sample. In this example, the adhesive layer is cut to a square of 4cm, but the adhesive layer may be fixed to have a size that varies depending on the thickness of the adhesive layer, for example, 4cm in the lateral direction and 2cm in the longitudinal direction depending on the thickness of the adhesive layer (for example, 4cm in the case of 50 μm and 200 μm). The residual stress of the measurement sample was measured by a tensile test apparatus (apparatus name "Autograph AG-Xplus", manufactured by Shimadzu corporation). Specifically, the measurement was performed under the following measurement conditions by clamping both ends of the measurement sample to the jig of the apparatus. The residual stress value (initial) was calculated from the ratio of the test force after 300 seconds to the cross-sectional area of the sample. On the other hand, the residual stress value (after storage) was measured in the same manner as the residual stress value (initial) for the adhesive layer stored at 70℃for 7 days. The ratio [ residual stress value (after storage)/residual stress value (initial) ×100] of the residual stress value (after storage) was calculated as the cure rate when the residual stress value (initial) was set to 100.
< Measurement Condition >
Measurement mode: stress relaxation (hold after stretching to a prescribed inter-jig distance)
The distance between the initial jigs is as follows: 2cm
Stretching speed: 300mm/min
Stretching distance: 300 percent of
Holding time: 300s
(4) Appearance of
The adhesive layers prepared in examples and comparative examples were prepared by preparing an adhesive layer from which light diffusing fine particles were removed, and visually observing the adhesive layer. As a result, the pressure-sensitive adhesive layer from which the light-diffusing fine particles were removed was judged to be "o" when the appearance was transparent, and "x" when the appearance was clouded.
TABLE 1
The following describes variations of the disclosed invention.
[ Additional note 1] an adhesive composition comprising a base polymer having a refractive index of 1.4 or more or a polymerizable compound forming the base polymer and light-diffusing fine particles,
The aforementioned base polymer optionally has structural units derived from high refractive index monomers,
The total light transmittance of the adhesive layer when forming the adhesive layer is 69% or less,
When the content of the light diffusing fine particles in the pressure-sensitive adhesive layer at the time of forming the pressure-sensitive adhesive layer is X1 mass% and the content of the structural units derived from the high refractive index monomer in the base polymer is X2 mass%, the following formulas (1) and (2) are satisfied,
X2 is less than 29.8.
1.2X1+0.08X2+84.9≥90 (1)
2.3X1-0.46X2+105≤150 (2)
The adhesive composition according to appendix 2, wherein the base polymer is an acrylic polymer having a structural unit derived from a high refractive index monomer comprising a monomer having a refractive index of 1.5 or more.
[ Additional note 3] the adhesive composition according to additional note 1 or 2, which contains a colorant.
[ Additional note 4] A laminate sheet comprising an adhesive portion comprising an adhesive layer formed from the adhesive composition according to any one of additional notes 1 to 3.
The laminate according to item 4, wherein the outermost surface of the laminate is provided with an antiglare layer and/or an antireflection layer.
The laminate according to any one of appendixes 4 to 5, wherein the adhesive portion has a thickness of 500 μm or less.
The laminate according to any one of the additional notes 4 to 6, which is a sheet for sealing 1 or more optical semiconductor elements disposed on a substrate.
[ Additionally described 8] an optical semiconductor device comprising: a substrate, an optical semiconductor element disposed on the substrate, and the laminate sheet or cured product thereof described in appendix 7 for sealing the optical semiconductor element.

Claims (8)

1. An adhesive composition comprising a base polymer having a refractive index of 1.4 or more or a polymerizable compound forming the base polymer and light-diffusing fine particles,
The base polymer optionally has structural units derived from high refractive index monomers,
The total light transmittance of the adhesive layer when the adhesive layer is formed is 69% or less,
When the content of the light diffusing fine particles in the pressure-sensitive adhesive layer at the time of forming the pressure-sensitive adhesive layer is X1 mass% and the content of the structural units derived from the high refractive index monomer in the base polymer is X2 mass%, the following formulas (1) and (2) are satisfied,
X2 is less than 29.8 and,
1.2X1+0.08X2+84.9≥90 (1)
2.3X1-0.46X2+105≤150 (2)。
2. The adhesive composition according to claim 1, wherein the base polymer is an acrylic polymer having a structural unit derived from a high refractive index monomer comprising a monomer having a refractive index of 1.5 or more.
3. The adhesive composition of claim 1, comprising a colorant.
4. A laminate sheet comprising an adhesive portion comprising an adhesive layer formed from the adhesive composition according to claim 1.
5. The laminate according to claim 4, which comprises an antiglare treatment layer and/or an antireflection treatment layer on one outermost surface.
6. The laminate sheet according to claim 4, wherein the thickness of the adhesive portion is 500 μm or less.
7. The laminated sheet according to any one of claims 4 to 6, which is a sheet for sealing 1 or more optical semiconductor elements arranged on a substrate.
8. An optical semiconductor device, comprising: a substrate, an optical semiconductor element disposed on the substrate, and the laminate sheet or cured product thereof according to claim 7 sealing the optical semiconductor element.
CN202410034474.1A 2023-01-11 2024-01-10 Adhesive composition, laminate, and optical semiconductor device Pending CN118325530A (en)

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