CN114774031A - Adhesive and polarizing plate comprising same - Google Patents
Adhesive and polarizing plate comprising same Download PDFInfo
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- CN114774031A CN114774031A CN202210431150.2A CN202210431150A CN114774031A CN 114774031 A CN114774031 A CN 114774031A CN 202210431150 A CN202210431150 A CN 202210431150A CN 114774031 A CN114774031 A CN 114774031A
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- adhesive
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- polarizing plate
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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
- C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
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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
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/02—Non-macromolecular additives
- C09J11/06—Non-macromolecular additives organic
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
- G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
- G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
- G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
- G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Adhesives Or Adhesive Processes (AREA)
- Polarising Elements (AREA)
- Orthopedics, Nursing, And Contraception (AREA)
Abstract
The embodiment of the invention provides an adhesive and a polarizing plate comprising the same, wherein the adhesive comprises: (A) a main agent of acrylic resin; (B) a bridging agent; and (C) a crosslinking promoter, wherein the crosslinking promoter (C) comprises the structure:
wherein R is a C1 to C4 alkyl group.
Description
Technical Field
The disclosure relates to an adhesive and an application thereof.
Background
The current polarizing plate process relates to a coating process of a pressure sensitive adhesive, wherein the anchoring force of the pressure sensitive adhesive to a relatively poor film directly affects the processability of the polarizer, if the anchoring force is poor, the adhesive overflows from a processing section during processing, or the adhesive is torn off when the release film of the polarizer is torn off, so that the adhesiveness is seriously affected.
Thus, while existing adhesives have been generally satisfactory in all respects, there remains a need for improvement.
Disclosure of Invention
An embodiment of the present invention provides an adhesive, including: (A) a main agent of acrylic resin; (B) a bridging agent;
and (C) a crosslinking promoter, wherein the crosslinking promoter (C) comprises the structure:
wherein, R is C1-C4 alkyl.
An embodiment of the present invention provides a display device, including: a polarizing film; a protective film on one side of the polarizing film; a functional film positioned at the other side of the polarizing film, wherein the functional film comprises acetyl cellulose; and the adhesive layer comprises the adhesive and is positioned on one side of the functional film away from the polarizing film.
In order to make the features of the present disclosure comprehensible, embodiments accompanied with figures are described in detail below, and other attention is paid to the technical field.
Drawings
Various aspects of the disclosure are described in detail below with reference to the following drawings. It should be noted that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the elements may be arbitrarily increased or reduced to clearly illustrate the features of the present disclosure.
FIG. 1 is a cross-sectional view of a polarizer according to some embodiments of the present disclosure;
fig. 2 is a schematic diagram illustrating the radical interaction of acetyl cellulose of a functional film with a binder, according to some embodiments of the present disclosure.
[ description of symbols ]
1: polarizing plate
10: surface protective film
20: optical film
30: adhesive layer
40: release film
210: protective film
212: first adhesive layer
214: polarizing film
216: second adhesive layer
218: functional film
Detailed Description
The following disclosure provides many embodiments, or examples, for implementing different elements of the provided subject matter. Specific examples of components and arrangements thereof are described below to simplify the description of the embodiments of the invention. These are, of course, merely examples and are not intended to limit the embodiments of the invention. For example, references in the description to a first element being formed on a second element may include embodiments in which the first and second elements are in direct contact, and may also include embodiments in which additional elements are formed between the first and second elements such that they are not in direct contact. Moreover, embodiments of the invention may use repeated reference numerals in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
Also, spatially relative terms, such as "below" … …, "below," "lower," "above," "higher," and the like, may be used herein to facilitate describing one element or feature's relationship to another element or feature in the drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. When the device is turned to a different orientation (rotated 90 degrees or otherwise), the spatially relative adjectives used herein will also be interpreted in terms of the turned orientation.
As used herein, the term "about", "approximately", "substantially" generally means within 5%, preferably within 3%, more preferably within 1%, or within 2%, or within 1%, or within 0.5% of a given value or range. The amounts given herein are approximate, that is, the meanings of "about", "about" and "substantially" may be implied without specifically stating "about", "about" or "substantially".
The current polarizing plate process involves a coating process of a pressure sensitive adhesive, wherein the anchoring force of the pressure sensitive adhesive to a retardation film directly affects the processability of the polarizer, if the anchoring force is poor, the adhesive may overflow from the processing section or the polarizer may tear the adhesive when the release film is torn off, and furthermore, the current pressure sensitive adhesive is generally poor in anchoring force to the retardation film made of acetyl cellulose.
In order to improve the anchoring force of the adhesive, the retardation film may be subjected to corona treatment or the moving rate of the retardation film may be reduced, wherein the corona treatment of the retardation film may increase the anchoring force of the adhesive on the retardation film by increasing the discharge power, but this may cause the polarizer to be deteriorated by excessive heating; and the corona treatment can generate tiny fragments, thereby reducing the cleanliness of the coating process and improving the production cost. In addition, the improvement of anchoring force by reducing the moving speed of the retardation film leads to a reduction in productivity, which is disadvantageous for production.
The present invention therefore ameliorates this problem. The invention provides a simple method for improving the anchoring force under the conditions of not changing the composition of the adhesive, not influencing the cleanliness of the process and not reducing the productivity, and the anchoring force is improved by adding substances capable of generating free radicals in the blending stage of the adhesive.
The adhesive and the polarizing plate provided in the present application will be described in detail below. It is to be understood that the specific components and arrangements are not to be considered as limiting the scope of the present disclosure, but rather as merely providing a concise and clear description of some embodiments of the disclosure.
[ Adhesives ]
An embodiment of the present invention provides an adhesive, including:
(A) a main agent of acrylic resin;
(B) a bridging agent; and
(C) a crosslinking facilitator, wherein the crosslinking facilitator (C) comprises the structure:
wherein, R is C1-C4 alkyl, the crosslinking accelerant (C) can generate free radicals after being irradiated by ultraviolet light, thereby improving the anchoring force and the adhesive force, and leading the adhesive force of the adhesive to be more than or equal to 3N/25mm and less than 7N/25mm, preferably more than or equal to 4.5N/25mm and less than 6N/25 mm; and the anchoring force of the adhesive to the phase difference film made of acetyl cellulose is more than 3mm and less than 10mm, preferably more than 5mm and less than 9 mm.
In detail, the adhesive according to the embodiment of the present invention includes: 98-99.9 wt% of an acrylic resin main agent (A); 0.05 to 1.5 wt% of a bridging agent (B); and 0.01 to 1.0 wt% of a crosslinking accelerator (C).
In a particular embodiment, the adhesive includes: 98.5 to 99.5% by weight of an acrylic resin base (A); 0.4 to 0.9 wt% of a bridging agent (B); and 0.05 to 0.6 wt% of a crosslinking accelerator (C).
The following will describe the components of the adhesive in detail:
[ (A) acrylic resin Main agent ]
The acrylic resin main agent used in the present invention may include at least one (meth) acrylate. It should be noted that since methyl is a relatively small functional group, many of the components in the art of the present invention are equally applicable when hydrogen is replaced by methyl, and therefore for the sake of simplicity it is customary to use "(methyl)" to indicate the applicability of both. For example, (meth) acrylates are the case where both acrylates and methacrylates are included.
According to some embodiments, the (meth) acrylate monomer comprises at least one compound selected from the group consisting of: a (meth) acrylate having an alkyl group, a (meth) acrylate having an alkoxy group, a (meth) acrylate having a halogen atom, a (meth) acrylate having an alicyclic group, a (meth) acrylate having an aryl group, a (meth) acrylate having an aryloxy group, or a combination thereof.
In some embodiments, the (meth) acrylate having an alkyl group may include a linear or branched alkyl (meth) acrylate.
In some embodiments, the (meth) acrylate of the linear alkyl group may be, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-octyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tetradecyl (meth) acrylate, and the like, but is not limited thereto.
In some embodiments, the (meth) acrylate of a branched alkyl group may be, for example, isopropyl (meth) acrylate, isobutyl (meth) acrylate, second butyl (meth) acrylate, third butyl (meth) acrylate, 2-ethylbutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and the like, but is not limited thereto.
In some embodiments, the (meth) acrylate having an oxyalkyl group may be, for example, an alkyl (meth) acrylate substituted with an alkoxy group such as 2-methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, etc., but is not limited thereto.
In some embodiments, the (meth) acrylate having a halogen atom may be, for example, 3-fluoroethyl acrylate, 4-fluoropropyl acrylate, or the like, but is not limited thereto.
In some embodiments, the (meth) acrylate having an alicyclic group may be, for example, tricyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, or the like, but is not limited thereto.
In some embodiments, the (meth) acrylate having an aryl group may be, for example, benzyl (meth) acrylate, etc., but is not limited thereto.
In some embodiments, the (meth) acrylate having an aryloxy group may be, for example, 2-phenoxyethyl (meth) acrylate, 2- (2-phenoxyethoxy) ethyl (meth) acrylate, ethylene oxide-modified (meth) acrylate of nonylphenol, 2- (o-phenylphenoxy) ethyl (meth) acrylate, and the like, but is not limited thereto.
According to some embodiments of the present invention, the content of the acrylic resin main agent (a) is preferably 98 to 99.9 wt%, more preferably 98.5 to 99.5 wt%, with respect to the total weight of the adhesive composition.
[ (B) bridging agent ]
In some embodiments, the bridging agent (B) may help the acrylic resin main agent (a) to generate cross-linking, forming a network structure to improve the strength of the adhesive.
The type of the crosslinking agent (B) is not particularly limited, and a crosslinking agent commonly used in the related art may be appropriately used. For example, the crosslinking agent (B) may include a polyisocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde compound, a methylol polymer, etc., but is not limited thereto. Preferably, a polyisocyanate compound may be used.
In some embodiments, the bridging agent (B) may be a multifunctional isocyanate compound with a functionality of less than or equal to 3, preferably a multifunctional isocyanate compound with a functionality of at least 2, so as to chemically bond with the acrylic resin main agent (a) and the crosslinking accelerator (C). According to some embodiments, the isocyanate-based compound used may be, for example, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, ditolyl diisocyanate, hydrogenated ditolyl diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, diphenylmethane diisocyanate, but is not limited thereto. According to some embodiments, the isocyanate compound used may be a dimer of any of the foregoing, a trimer of any of the foregoing, and/or an adduct formed by reacting any of the foregoing with a polyol, but is not limited thereto.
In some embodiments, the epoxy polymer may be used alone or in combination, and the epoxy polymer may be, for example, a bisphenol a-based epoxy resin, a hydrogenated bisphenol a-based epoxy resin, a bisphenol F-based epoxy resin, a hydrogenated bisphenol F-based epoxy resin, a novolac (novolac) -type epoxy resin, a cyclic aliphatic epoxy resin, a heterocyclic (heterocyclic) epoxy resin, a glycidyl ester (glycidyl ester) based resin, a glycidyl amine (glycidyl amine) based resin, an epoxidized oil, a brominated derivative of the foregoing epoxy resin, tris (glycidyl phenyl) methane [ tris (glycidyl phenyl) methane ], or triglycidyl isocyanate (triglycidyl isocyanurate), or the like, but is not limited thereto. Preferably, the epoxy resin is selected from bisphenol a epoxy resins, hydrogenated bisphenol a epoxy resins, novolac epoxy resins, cyclic aliphatic epoxy resins, glycidyl ester resins, glycidyl amine resins, tris (glycidylbenzene) methane, or combinations thereof. Specific examples of the epoxy polymer include commercially available products EX111, EX201, EX411 and EX901 from Nagase ChemteX Corporation; EPPN501H, a commercially available product of Nippon chemical Co., Ltd; and EPIKOTE 152, a commercially available product of YUKA SHELL EPXY.
In some embodiments, the melamine-based compound may be, for example, hexamethylolmelamine (hexamethylolmelamine), pentamethylmelamine (pentamethylolmelamine), tetramethylolmelamine (tetramethylolmelamine), hexamethoxymethylmelamine (hexamethoxymethylmelamine), pentamethylmethylmelamine (pentamethylmethylmelamine), tetramethoxymethylmelamine (tetramethylymethylmelmine), hexaethoxymethylmelamine (hexaethoxymethylmelamine), or the like, but is not limited thereto.
In some embodiments, the methylol compound may be, for example, 2,6-bis (hydroxymethyl) -4-cresol [2,6-bis (hydroxymethyl) -4-methylphenol ], 4-tertiary butyl-2,6-bis (hydroxymethyl) phenol [4-tert-butyl-2,6-bis (hydroxymethyl) phenol ], 5-ethyl-1,3-bis (hydroxymethyl) -perhydro-1,3,5-triazine-2-one [5-ethyl-1,3-bis (hydroxymethyl) -perhydro-2-one ], dimethylolpropyleneurea (dimethylolpropyleneurea), 3,5-bis (hydroxymethyl) -perhydro-1,3, 5-dioxazin-4-one [3,5-bis (hydroxymethyl) -perhydro-1,3,5-oxadiazine-4-one ], or tetramethylglyoxaldiolein, but not limited thereto.
According to some embodiments of the present invention, the content of the bridging agent (B) is preferably 0.05 to 1.5 wt%, more preferably 0.4 to 0.9 wt%, based on the total weight of the adhesive composition.
[ (C) crosslinking accelerator ]
In some embodiments, the crosslinking accelerator (C) can generate a radical upon irradiation with ultraviolet light, thereby improving anchoring force.
In some embodiments, the crosslinking facilitator (C) comprises the structure:
wherein R ═ C1 to C4 alkyl, more preferably, R is methyl or ethyl.
In some embodiments, the crosslinking accelerator (C) generates the structure of formula 1 and the structure of formula 2 after being irradiated by uv light
[ chemical formula 1]
[ chemical formula 2]
Wherein R ═ C1 to C4 alkyl, more preferably, R is methyl or ethyl.
In some embodiments, the hydroxyl group of the crosslinking promoter (C) may bond with the bridging agent (B), thereby improving anchorage and adhesion. For example, in the case of the bridging agent (B) of the polyisocyanate compound, it can react with the hydroxyl group of the crosslinking accelerator (C) as shown in formula one:
wherein R' -OH generation after UV irradiation
And
r is C1-C4 alkyl,
OCN-R' is the bridging agent (B) for the polyisocyanate compound described earlier,
r' is alkane or aromatic hydrocarbon.
In some embodiments, the crosslinking accelerator (C) has a structure as shown in chemical formula 3, chemical formula 4, or a combination thereof
[ chemical formula 3]
[ chemical formula 4]
In some embodiments, the crosslinking promoter (C) is configured to generate free radicals that react with the material of the functional film 218, such as acetyl cellulose (described below), such that the acetyl cellulose oxidizes to generate oxygen-containing functional groups, or such that the crosslinking promoter (C) bonds with the acetyl cellulose. For example, as shown in FIG. 2, the crosslinking accelerator (C) which generates radicals after irradiation with ultraviolet light is represented by R1And the appearance in which free radicals are contained as the crosslinking promoters R1The linting free radicals react with the acetyl cellulose of the functional film 218, so that the acetyl cellulose is oxidized to generate the oxygen-containing functional groups (for example, hydroxyl group, carboxyl group).
In some embodiments, the oxygen-containing functional group of acetyl cellulose may further improve anchoring force and adhesion since it may form a hydrogen bond with the acrylic resin main component (a) of the adhesive or may form a covalent bond with the bridging agent (B) of the adhesive.
According to some embodiments of the invention, the crosslinking accelerator (C) comprises less than or equal to 0.5 wt% of the adhesive. In some embodiments, the crosslinking accelerator (C) is preferably present in an amount of 0.01 to 1.0 wt%, more preferably 0.05 to 0.6 wt%, based on the total weight of the adhesive composition.
[ polarizing plate ]
Fig. 1 is a cross-sectional view of a polarizer 1 according to some embodiments. As shown in fig. 1, in some embodiments, the optical film 20 includes a polarizing film 214, a protective film 210 disposed on one side of the polarizing film 214, and a functional film 218 disposed on the other side of the polarizing film 214.
With continued reference to fig. 1, in some embodiments, the polarizing plate 1 includes the optical film 20 and the adhesive layer 30 disposed on the side of the functional film 218 away from the polarizing film 214. In some embodiments, the polarizing plate 1 further includes a surface protection film 10 disposed on the side of the protection film 210 away from the polarizing film 214, and a release film 40 disposed on the side of the adhesive layer 30 away from the functional film 218. When the polarizing plate 1 is used, the release film 40 is peeled off and attached to the display panel through the adhesive layer 30. In some embodiments, after the polarizing plate 1 is attached to a display panel (not shown) through the adhesive layer 30, the surface protection film 10 may be removed, wherein the polarizing plate 1 may be attached to a first surface and/or a second surface of the display panel, and the first surface is opposite to the second surface. In some embodiments, the display panel may be a liquid crystal display panel, for example, an IPS liquid crystal display panel, or a VA liquid crystal display panel.
In some embodiments, the material of the polarizing film 214 may be a Polyvinyl alcohol (PVA) resin film, which may be made by saponifying a Polyvinyl acetate resin. The saponification degree of the polyvinyl alcohol resin is usually about 85 mol% or more. Examples of the polyvinyl acetate resin include a homopolymer of vinyl acetate (i.e., polyvinyl acetate), and a copolymer of vinyl acetate and other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids (e.g., acrylic acid, methacrylic acid, ethyl acrylate, n-propyl acrylate, methyl methacrylate), olefins (e.g., ethylene, propylene, 1-butene, 2-methylpropene), vinyl ethers (e.g., ethyl vinyl ether, methyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether), unsaturated sulfonic acids (e.g., vinylsulfonic acid, sodium vinylsulfonate), and the like. Specific examples of the copolymer of vinyl acetate and another monomer copolymerizable therewith include ethylene-vinyl acetate copolymers. The polymerization degree of the polyvinyl alcohol resin is usually about 1000 to 10000, preferably about 1500 to 5000. The polyvinyl alcohol resin may be modified, and for example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral, or the like modified with aldehydes can be used.
In some embodiments, the polarizing film 214 has a thickness of 5 to 35 microns, preferably 20 to 30 microns, such as about 25 microns.
The protective film 210, the release film 40 and the surface protective film 10 are used to protect the polarizing film 214. In some embodiments, the material of the protective film 210 and the surface protective film 10 may be, for example, a thermoplastic resin with excellent transparency, mechanical strength, thermal stability, moisture barrier property, and the like. The thermoplastic resin may include acetyl cellulose resin (e.g., triacetyl cellulose (TAC), diacetyl cellulose (DAC)), acrylic resin (e.g., poly (methyl methacrylate), PMMA), polyester resin (e.g., polyethylene terephthalate (PET), polyethylene naphthalate), olefin resin, polycarbonate resin, cycloolefin resin, oriented-stretched polypropylene (OPP), Polyethylene (PE), polypropylene (PP), Cyclic Olefin Polymer (COP), Cyclic Olefin Copolymer (COC), polycarbonate (polycarbonate), Polycarbonate (PC), or any combination thereof Urethane series (e.g., Polyurethane (PU)), acrylic urethane series (e.g., polyacrylic urethane), epoxy series (e.g., epoxy resin), silicone series (e.g., silicone resin), and the like. Further, the protective film 210, the release film 40, and the surface protective film 10 may be subjected to a surface treatment, such as an anti-glare treatment, an anti-reflection treatment, a hard coat treatment, a charge prevention treatment, or an anti-stain treatment. In addition, in some embodiments, the protective film 210, the release film 40 and the surface protective film 10 are a single-layer or multi-layer optical film.
In some embodiments, the thicknesses of the protective film 210, the release film 40 and the surface protective film 10 can be respectively 5 to 90 micrometers, preferably 35 to 80 micrometers.
In some embodiments, the functional film 218 may comprise acetyl cellulose (e.g., triacetated cellulose (TAC), diacetylated cellulose (DAC)). The functional film 218 is a protective film or a retardation film, and in some embodiments, the functional film 218 provides a proper retardation, the in-plane retardation of the functional film 218 may be 30nm to 90nm, and the thickness-direction retardation may be 120nm to 200 nm.
In some embodiments, the functional film 218 has a thickness of less than 60 microns, preferably 20 to 55 microns.
The adhesive layer 30 may include an adhesive as described above, which may have a fixing or protecting function. Since the adhesive of the adhesive layer 30 includes the crosslinking promoter (C) configured to generate a radical that reacts with the acetyl fiber of the functional film 218, so that the acetyl cellulose is oxidized to generate an oxygen-containing functional group, or so that the crosslinking promoter (C) is bonded to the acetyl cellulose, and further, the oxygen-containing functional group of the acetyl cellulose may form a hydrogen bond with the acrylic resin main agent (a) of the adhesive, or may form a chemical bond with the bridging agent (B) of the adhesive, the anchoring force may be further improved so that the anchoring force of the adhesive to the acetyl cellulose is greater than 3mm and less than 10mm, preferably, greater than 5mm and less than 9 mm.
In some embodiments, the adhesive layer 30 has a thickness of 15-40 microns, preferably 17-23 microns.
In some embodiments, the optical film may further include an adhesive layer between the protective film 210 and the polarizing film 214, and/or between the functional film 218 and the polarizing film 214. For example, the first adhesive layer 212 is disposed between the protective film 210 and the polarizing film 214, and the second adhesive layer 216 is disposed between the functional film 218 and the polarizing film 214. The adhesive layer may contain an aqueous adhesive, and is generally a composition prepared by using a polyvinyl alcohol resin or a urethane resin as a main component of the aqueous adhesive, and adding a crosslinking agent or a curable compound such as an isocyanate compound or an epoxy compound to improve the adhesion.
In some examples, when the main component of the aqueous adhesive is a polyvinyl alcohol resin, modified polyvinyl alcohol resins such as carboxyl-modified polyvinyl alcohol, acetyl-modified polyvinyl alcohol, hydroxymethyl-modified polyvinyl alcohol, and amino-modified polyvinyl alcohol may be used in addition to partially saponified polyvinyl alcohol and completely saponified polyvinyl alcohol. The aqueous solution of the polyvinyl alcohol resin can be used as an aqueous adhesive, and the concentration of the polyvinyl alcohol resin in the aqueous adhesive is usually 1 to 10 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of water.
In some embodiments, in order to improve the adhesion as described above, a curable compound such as a polyvalent aldehyde, a water-soluble epoxy resin, a melamine compound, a zirconia compound, and a zinc compound may be added to the aqueous adhesive comprising an aqueous solution of a polyvinyl alcohol resin.
In some embodiments, the adhesive layer may be a uv curable adhesive, and the materials may be exemplified by: acrylic adhesives, epoxy adhesives, urethane adhesives, polyester adhesives, polyvinyl alcohol adhesives, polyolefin adhesives, modified polyolefin adhesives, polyvinyl alkyl ether adhesives, rubber adhesives, vinyl chloride-vinyl acetate adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer) adhesives, ethylene adhesives such as ethylene-styrene copolymers, and acrylic adhesives such as ethylene-methyl (meth) acrylate copolymers and ethylene-ethyl (meth) acrylate copolymers.
In order to make the aforementioned and other objects, features, and advantages of the present disclosure more comprehensible, several test results of examples and comparative examples are listed below to illustrate the characteristics of the adhesive prepared by applying the present disclosure. However, the following examples and comparative examples are illustrative only and should not be construed as limiting the practice of the present disclosure.
[ first table ]
Synthesis example 1 crosslinking Accelerator (C1)
Benzoin condensation: 10 ml of hydroxybenzaldehyde, 0.1g of sodium cyanide, 0.1g of tetrabutylammonium bromide and 10 ml of absolute ethanol were mixed, heated to boiling with stirring, and subjected to a water-splitting reaction under reflux for 8 to 10 hours to obtain 9g of a dihydroxy benzoin mixture.
And (3) etherification reaction step: 9g of the mixture of dihydroxybenzols, 9 ml of anhydrous methanol, 20 ml of toluene and 1 ml of 1M hydrochloric acid were mixed, heated to boiling with stirring, refluxed and reacted for 4 to 6 hours by water separation.
And (3) water washing: adding 20 ml of 1M sodium chloride aqueous solution into the obtained mixture, uniformly stirring, standing for layering, and removing a water layer; adding 20 ml of 1M sodium hydroxide aqueous solution into the mixture washed by the brine, uniformly stirring, standing for layering, and removing a water layer; adding 20 ml of clear water into the mixture washed by the sodium hydroxide aqueous solution, stirring uniformly, standing for layering, and removing the water layer.
And (3) decompression desolventizing: and (3) distilling out toluene in the obtained mixture at the temperature of 100 ℃ by adopting a 35mmHg water jet pump, wherein the residual product is the finished product of the dihydroxy benzoin methyl ether.
[ Synthesis example 2] crosslinking Accelerator (C2)
Condensation of benzoin: 10 ml of hydroxybenzaldehyde, 0.1g of sodium cyanide, 0.1g of tetrabutylammonium bromide and 10 ml of absolute ethanol were mixed, heated to boiling with stirring, and subjected to a water-splitting reaction under reflux for 8 to 10 hours to obtain 9g of a dihydroxy benzoin mixture.
And (3) etherification reaction step: 9g of the mixture of dihydroxybenzoins, 9 ml of absolute ethanol, 20 ml of toluene and 1 ml of 1M hydrochloric acid are mixed, heated to boiling under stirring, and refluxed and dehydrated for 4 to 6 hours.
And (3) water washing: adding 20 ml of 1M sodium chloride aqueous solution into the obtained mixture, stirring uniformly, standing for layering, and removing a water layer; adding 20 ml of 1M sodium hydroxide aqueous solution into the mixture washed by the brine, uniformly stirring, standing for layering, and removing a water layer; adding 20 ml of clear water into the mixture washed by the sodium hydroxide aqueous solution, stirring uniformly, standing for layering, and removing the water layer.
And (3) decompression desolventizing: and (3) distilling off the toluene in the obtained mixture at the temperature of 100 ℃ by adopting a 35mmHg water jet pump, wherein the residual product is the finished product of the dihydroxy benzoin ethyl ether.
[ Synthesis example 3] crosslinking Accelerator (C3)
Benzoin condensation: 10 ml of methylbenzaldehyde, 0.1g of sodium cyanide, 0.1g of tetrabutylammonium bromide and 10 ml of anhydrous ethanol were mixed, heated to boiling with stirring, and subjected to a water-splitting reaction under reflux for 8 to 10 hours to obtain 9g of a dihydroxy benzoin mixture.
And (3) etherification reaction step: 9g of dihydroxy benzoin mixture, 9 ml of anhydrous methanol, 20 ml of toluene and 1 ml of 1M hydrochloric acid are mixed, heated to boiling under stirring, refluxed and subjected to water-splitting reaction for 4-6 hours.
And (3) water washing: adding 20 ml of 1M sodium chloride aqueous solution into the obtained mixture, uniformly stirring, standing for layering, and removing a water layer; adding 20 ml of 1M sodium hydroxide aqueous solution into the mixture washed by the brine, uniformly stirring, standing for layering, and removing a water layer; adding 20 ml of clear water into the mixture washed by the sodium hydroxide aqueous solution, stirring uniformly, standing for layering, and removing the water layer.
And (3) decompression desolventizing: and (3) distilling out toluene in the obtained mixture at the temperature of 100 ℃ by adopting a 35mmHg water jet pump, wherein the residual product is the finished product of the dimethyl benzoin methyl ether.
[ example 1]
When the solid content of each composition was 100%, 100g of the acrylic resin base (A) (having a trade name of "COPONYL S-086/S-094/S-449/S-681", manufactured by Mitsubishi chemical corporation) (98.9 wt%), 0.6g of the crosslinking agent (B) (having a trade name of "CORONATE L", manufactured by Nippon Toso Co., Ltd.) (0.59 wt%), and 0.51g of the crosslinking accelerator (C1) prepared in Synthesis example (0.5 wt%) were mixed to prepare an adhesive composition, and the adhesive composition was applied to a polarizing plate, and then the adhesive composition was irradiated with ultraviolet light to generate radicals, followed by drying in a drying oven.
[ example 2]
The adhesive composition of this example was prepared in the same manner as in example 1, except that the crosslinking accelerator (C2) used in example 2 was the crosslinking accelerator (C2) used in synthesis example 2.
Comparative example 1
The adhesive composition of this comparative example was prepared in the same manner as in example 2, except that the content of the crosslinking accelerator (C2) in the adhesive was changed to 0.75 wt%.
Comparative example 2
The adhesive composition of this comparative example was prepared in the same manner as in example 1, except that the crosslinking accelerator (C3) used in synthesis example 3 was changed.
[ production of polarizing plate ]
First, an aqueous adhesive is directly applied to a first side and a second side of a polarizing film opposite to each other by a coating device to form an adhesive layer, and then a protective film and a functional film are respectively attached to the adhesive layers on both sides of the polarizing film, thereby obtaining an optical film. Then, directly coating the adhesive on the side of the functional film far away from the polarizing film by a coating device, and passing through ultraviolet light with a wavelength of 280-310 nm at 200mw/cm2Illumination intensity of (2) and 200mj/cm2The integrated light amount of (a) was irradiated to obtain a polarizing plate used in the present experiment.
[ measurement of anchoring force ]
A rubber strip was rubbed 10 times against the polarizer to measure the distance of the separation of the glue.
[ measurement of adhesive force ]
The polarizing plate is peeled from the glass at 180 degrees and the force when the adhesion surface and the stretching surface are pulled at 180 degrees is measured to obtain the adhesive force.
As can be seen from the results in Table I, the adhesives of examples 1 and 2 each have a hydroxyl group as a part of the crosslinking accelerator can bond with acetyl cellulose and another part of the crosslinking accelerator can oxidize acetyl cellulose, wherein the part of the crosslinking accelerator that oxidizes acetyl cellulose can form a covalent bond with the crosslinking agent through the hydroxyl group without becoming a free part for reducing the adhesive force, and thus can have an adhesive force of 3N/25mm or more and an anchoring force of less than 10mm to acetyl cellulose. In contrast, the crosslinking accelerator used in comparative example 2 has no hydroxyl group, and therefore, a part of the crosslinking accelerator oxidizing acetyl cellulose cannot form a covalent bond with the crosslinking agent through the hydroxyl group, but becomes a free part reducing the adhesive force, resulting in an adhesive force of less than 3N/25mm, and having an anchoring force of greater than or equal to 10mm to acetyl cellulose.
Furthermore, as can be seen from the results in Table I, examples 1 and 2 used crosslinking accelerators having a binder content of 0.5% by weight or less, an adhesive force of 3N/25mm or more and an anchoring force of 10mm or less with respect to acetyl cellulose. In contrast, comparative example 1 used a crosslinking accelerator in an amount of more than 0.5 wt% based on the adhesive, resulting in an adhesive force of less than 3N/25mm and having an anchoring force of 10mm or more against acetyl cellulose.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present embodiments. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present invention is subject to the scope defined by the appended claims.
Claims (19)
1. An adhesive, comprising:
(A) a main agent of acrylic resin;
(B) a bridging agent; and
(C) a crosslinking facilitator, wherein the crosslinking facilitator (C) comprises the structure:
wherein, R is C1-C4 alkyl.
2. The adhesive according to claim 1, wherein the hydroxyl group of the crosslinking accelerator (C) is bonded to the bridging agent (B), and the crosslinking accelerator (C) generates a radical under the irradiation of ultraviolet light.
3. Adhesive according to claim 1, characterized in that it comprises: 98-99.9 wt% of the acrylic resin main agent (A); 0.05 to 1.5 wt% of the bridging agent (B); and 0.01 to 1.0 wt% of the crosslinking accelerator (C).
4. Adhesive according to claim 1, characterized in that the crosslinking promoter (C) is present in an amount of less than or equal to 0.5% by weight of the adhesive.
5. The adhesive of claim 1, wherein the crosslinking promoter (C) generates the structure of formula 1 and the structure of formula 2 after being irradiated by ultraviolet light
[ chemical formula 1]
[ chemical formula 2]
Wherein, R is C1-C4 alkyl.
6. Adhesive according to claim 1, characterized in that R in the crosslinking promoter (C) is methyl or ethyl.
7. The adhesive of claim 1, wherein the crosslinking accelerator (C) has a structure of formula 3, a structure of formula 4, or a combination thereof
[ chemical formula 3]
[ chemical formula 4]
8. The adhesive of claim 1, wherein the bridging agent (B) comprises a polyfunctional isocyanate compound, an epoxy resin, a melamine resin, a urea resin, a dialdehyde compound, a methylol polymer, or a combination thereof.
9. The adhesive of claim 8, wherein the bridging agent (B) is a polyfunctional isocyanate compound having a functionality of less than or equal to 3.
10. Adhesive according to claim 1, characterized in that the adhesive force is greater than or equal to 3N/25mm and less than 7N/25 mm.
11. A polarizing plate, comprising:
a polarizing film;
a protective film located on one side of the polarizing film;
a functional film positioned on the other side of the polarizing film, wherein the functional film comprises acetyl cellulose; and
an adhesive layer comprising the adhesive of any one of claims 1 to 10, on a side of the functional film away from the polarizing film.
12. The polarizing plate of claim 11, wherein the cross-linking promoter (C) of the adhesive is configured to generate a radical that reacts with the acetyl cellulose, such that the acetyl cellulose is oxidized to generate an oxygen-containing functional group or the cross-linking promoter (C) is bonded to the acetyl cellulose.
13. The polarizing plate of claim 12, wherein a hydrogen bond is formed between the oxygen-containing functional group of the acetyl cellulose and the acrylic resin main agent (a) of the adhesive.
14. The polarizing plate of claim 12, wherein the oxygen-containing functional group of the acetyl cellulose is chemically bonded to the bridging agent (B) of the adhesive.
15. The polarizing plate of claim 11, wherein the anchoring force of the adhesive to the acetyl cellulose is greater than 3mm and less than 10 mm.
16. The polarizing plate of claim 11, wherein the functional film has a film in-plane phase difference value of 30nm to 90nm and a thickness direction phase difference value of 120nm to 200 nm.
17. The polarizing plate according to claim 11, further comprising:
a surface protection film, which is positioned on one side of the protection film far away from the polarizing film; and
and the release film is positioned on one side of the adhesive layer, which is far away from the functional film.
18. The polarizing plate of claim 11, further comprising:
and the adhesive layer is positioned between the protective film and the polarizing film and/or between the functional film and the polarizing film.
19. A display device, comprising:
a display panel; and
the polarizing plate according to any one of claims 11 to 18, wherein the polarizing plate is attached to the display panel through the adhesive layer.
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|---|---|---|---|
| TW110140866A TWI805057B (en) | 2021-11-03 | 2021-11-03 | Adhesive agent and polarizing plate containing the same |
| TW110140866 | 2021-11-03 |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4368253A (en) * | 1981-01-28 | 1983-01-11 | Ciba-Geigy Corporation | Image formation process |
| US4632891A (en) * | 1984-10-04 | 1986-12-30 | Ciba-Geigy Corporation | Process for the production of images |
| CN103992752A (en) * | 2013-02-15 | 2014-08-20 | 琳得科株式会社 | Pressure-sensitive adhesive composition, pressure-sensitive adhesive agent and pressure-sensitive adhesive sheet |
| CN107353854A (en) * | 2017-07-14 | 2017-11-17 | 东莞市纳利光学材料有限公司 | A kind of OCA optical cements and OCA optical adhesive films |
-
2021
- 2021-11-03 TW TW110140866A patent/TWI805057B/en active
-
2022
- 2022-04-22 CN CN202210431150.2A patent/CN114774031B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4368253A (en) * | 1981-01-28 | 1983-01-11 | Ciba-Geigy Corporation | Image formation process |
| US4632891A (en) * | 1984-10-04 | 1986-12-30 | Ciba-Geigy Corporation | Process for the production of images |
| CN103992752A (en) * | 2013-02-15 | 2014-08-20 | 琳得科株式会社 | Pressure-sensitive adhesive composition, pressure-sensitive adhesive agent and pressure-sensitive adhesive sheet |
| CN107353854A (en) * | 2017-07-14 | 2017-11-17 | 东莞市纳利光学材料有限公司 | A kind of OCA optical cements and OCA optical adhesive films |
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| Publication number | Publication date |
|---|---|
| CN114774031B (en) | 2023-08-18 |
| TWI805057B (en) | 2023-06-11 |
| TW202319372A (en) | 2023-05-16 |
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