TW201801924A - Polarizer - Google Patents

Abstract

A polarizer comprises a polarizing layer, a first protective layer, a second protective layer and an adhesive layer. The first protective layer and the second protective layer are disposed on two sides of the polarizing layer, respectively. The first protective layer comprises an additive having an aromatic heterocycle. The adhesive layer is disposed on one side of the first protective layer oppose to the polarizing layer. The adhesive layer comprises a silane coupling agent. A value of an amount of the additive/an amount of the silane coupling agent is defined as Z, 2.5 < Z < 40.

Description

Polarizer

The present invention relates to a polarizing plate, and more particularly, to a polarizing plate containing a silane coupling agent.

Polarizing plates are widely used. For example, a liquid crystal display usually includes two polarizing plates, which are respectively disposed on two sides of the liquid crystal layer. By the polarizing plate and the liquid crystal molecules twisting together, the brightness of the liquid crystal display can be controlled. In addition, organic light emitting diode (OLED) displays usually include a polarizing plate. Circularly polarized light is used to reduce the reflectance on the OLED panel and reduce the dark state brightness to improve the contrast of the display. In accordance with the development of the applied device (such as a display), the polarizing plate itself needs to be adjusted accordingly. This can usually be achieved by adjusting the composition of its layers. When one layer of the polarizing plate is adjusted in order to achieve a certain characteristic requirement, the other layers of the polarizing plate may also need to be adjusted accordingly to achieve an optimal result.

The present invention provides a polarizing plate having good weather resistance.

According to some embodiments, the polarizing plate includes a polarizing base layer, a first protective layer, a second protective layer, and an adhesive layer. The first protective layer and the second protective layer are respectively disposed on two sides of the polarizing base layer. The first protective layer includes an additive having an aromatic heterocyclic ring. The adhesive layer is disposed on a side of the first protective layer opposite to the polarizing base layer. The adhesive layer includes a silane coupling agent. The value defining one content of the additive / one content of the silane coupling agent is equal to Z, 2.5 <Z <40.

In order to have a better understanding of the above and other aspects of the present invention, preferred embodiments are described below in detail with the accompanying drawings, as follows:

Please refer to FIG. 1, which illustrates a polarizing plate 100 according to an embodiment of the present invention. The polarizing plate 100 includes a polarizing base layer 102, a first protective layer 104, a second protective layer 106, and an adhesive layer 108. The first protective layer 104 and the second protective layer 106 are respectively disposed on two sides of the polarizing base layer 102. The first protective layer 104 includes an additive having an aromatic heterocyclic ring. The adhesive layer 108 is disposed on a side of the first protective layer 104 opposite to the polarizing base layer 102. The adhesive layer 108 includes a silane coupling agent. The value defining one content of the additive / one content of the silane coupling agent is equal to Z, 2.5 <Z <40. Preferably, 4 <Z <28.6. More preferably, 12.5 <Z <20. Here, the content of a component is relative to the content of the entire layer to which the component is added. For example, the content of the additive may be a ratio of the weight of the additive to the entire weight of the first protective layer 104, and the content of the silane coupling agent may be a ratio of the silane coupling agent to the entire weight of the adhesive layer 108.

According to some embodiments, the polarizing base layer 102 may include a binder and an iodine or dichroic dye aligned therein. The adhesive may use a polymer that is crosslinkable by itself, including but not limited to at least one selected from the group consisting of polyvinyl alcohol and denatured polyvinyl alcohol. Alternatively, a cross-linking agent such as a boron compound or the like may be added. Dichroic dyes include, but are not limited to, at least one selected from the group consisting of: azo dyes, stilbene dyes, pyrazoline dyes, triphenylmethane dyes, quinoline dyes , Oxazine-based dyes, thiazine-based dyes, or anthraquinone-based dyes. The dichroic dye preferably has a hydrophilic substituent such as a sulfo group, an amino group, a hydroxyl group, and the like.

In some embodiments, the polarizing substrate layer 102 may be formed by a polyvinyl alcohol (PVA) film adsorbing and aligning a dichroic pigment. For example, an iodine-based polarizer using iodine as a dichroic pigment. The formation of the polarizing base layer 102 generally includes the following steps: a swelling treatment, a dyeing treatment, a stretching treatment, a crosslinking treatment, a washing treatment, and a drying treatment. Among them, the stretching treatment imparts a polarizing effect to the polyvinyl alcohol.

The first protective layer 104 and the second protective layer 106 are used to provide the protective and mechanical support of the polarizing base layer 102. The first protective layer 104 and the second protective layer 106 are typically composed of cellulose or similar components, and the components can be adjusted according to different needs. For example, at least one of the first protective layer 104 and the second protective layer 106, such as the first protective layer 104, may have optical compensation properties.

In some embodiments, the material of the first protective layer 104 may be selected from polymethylmethacrylate (PMMA), Triacetyl Cellulose (TAC), acrylic resin film, and polyaromatic hydroxy resin film, respectively. , Polyether resin film, cyclic polyolefin resin film (such as polybornene resin film), polyester (Polyethylene Terephthalate, PET), polypropylene (Polypropylene, PP), cycloolefin polymer (Cyclo Olefin Polymer, COP), polymer A family of carbonates (Polycarbonate, PC) and any combination thereof, and may include additives having aromatic heterocycles. However, the reason why the first protective layer 104 includes an additive having an aromatic heterocyclic ring is not limited thereto.

其中R₁ 、R₂ 分別獨立地表示氫原子或取代基，取代基可為烷基、烯基、炔基、芳基、經取代或未取代胺基、烷氧基、芳氧基、羥基、或鹵素原子。取代基較佳地為烷基，特別是具有5至20個碳原子的烷基，尤其是具有5至12個碳原子的烷基。Unsaturated aromatic heterocycles are common types of additives. According to some embodiments, the aromatic heterocyclic ring may be a single-membered ring, a double-membered ring, or a three-membered ring, etc., preferably a single-membered ring or a double-membered ring, and more preferably a single-membered ring. According to some embodiments, the hetero atom in the aromatic heterocyclic ring is preferably a nitrogen atom, an oxygen atom, or a sulfur atom, and more preferably a nitrogen atom. According to some embodiments, the aromatic heterocyclic ring includes, but is not limited to, at least one selected from the group consisting of a furan ring, a thiophene ring, a pyrrole ring, an azole ring, an isoxazole ring, a thiazole ring, an isothiazole ring, Imidazole ring, pyrazole ring, furfuryl ring, triazole ring, pyran ring, pyridine ring, data ring, and pyrimidine ring. The aromatic heterocyclic ring is preferably a pyrrole ring. Formula 1 shows an exemplary additive N, N-(6-oxo-1,6-dihydroprimidine-2,4-diyl) diacetamide, which includes a pyrimidine ring. [Formula 1]

Wherein R ₁ and R ₂ each independently represent a hydrogen atom or a substituent, and the substituent may be an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, an aryloxy group, a hydroxyl group, Or a halogen atom. The substituent is preferably an alkyl group, particularly an alkyl group having 5 to 20 carbon atoms, and especially an alkyl group having 5 to 12 carbon atoms.

The material of the second protective layer 106 may include, but is not limited to, at least one selected from the group consisting of: polymethylmethacrylate (PMMA), triacetyl cellulose (TAC), Acrylic resin film, polyaromatic hydroxy resin film, polyether resin film, cyclic polyolefin resin film (such as polynorbornene resin film), polyester (Polyethylene Terephthalate, PET), polypropylene (Polypropylene, PP), cycloolefin polymer (Cyclo Olefin Polymer, COP), polycarbonate (Polycarbonate, PC), and any combination thereof.

According to some embodiments, the adhesive layer 108 may be a pressure-sensitive adhesive layer. According to some embodiments, the adhesive layer 108 includes a main agent, a cross-linking agent, an adhesion promoter, and a solvent.

其中R₃ 、R₄ 分別獨立地表示氫原子或取代基，取代基可為烷基、烯基、炔基、芳基、經取代或未取代胺基、烷氧基、芳氧基、羥基、或鹵素原子。取代基較佳地為烷基，特別是具有1至10個碳原子的烷基，尤其是具有1至5個碳原子的烷基。Base agents include, but are not limited to, at least one selected from the group consisting of: methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylic acid (Meth) acrylates such as 2-ethylhexyl ester and the like, and such as hydroxyethyl acrylate, 3-hydroxypropyl acrylate, hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4- Hydroxybutyl ester, 4-hydroxybutyl methacrylate, allyl alcohol, itaconic acid, acrylamide, cyanoethyl methacrylate, cyanoethyl acrylate, 6-hydroxyethyl methacrylate, etc. Hydroxy acrylate compounds. For example, mono (meth) acrylate and monohydroxyacrylate compounds can be selected in any composition ratio. Formula 2 shows the structure of a main agent molecule of an exemplary nature. The base agent molecule is usually a planar molecule. [Formula 2]

R ₃ and R ₄ each independently represent a hydrogen atom or a substituent, and the substituent may be an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amine group, an alkoxy group, an aryloxy group, a hydroxyl group, Or a halogen atom. The substituent is preferably an alkyl group, particularly an alkyl group having 1 to 10 carbon atoms, and especially an alkyl group having 1 to 5 carbon atoms.

The crosslinking agent includes, but is not limited to, at least one selected from the group consisting of an epoxy-based crosslinking agent, an isocyanate-based crosslinking agent, and an imine-based crosslinking agent.

其中Y表示取代基，取代基可為烷基、烯基、炔基、芳基、經取代或未取代胺基、烷氧基、芳氧基、環氧基、環烷氧基、羥基、或鹵素原子等。The adhesion promoter includes the silane coupling agent. Silane coupling agents include, but are not limited to, at least one selected from the group consisting of: vinyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxy Propyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and other silicon compounds having an epoxy group structure, such as 3-aminopropyltrimethoxysilane, Contains N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, etc. Amine-based silicon compounds, and 3-chloropropyltrimethoxysilane. Formula 3 shows the structure of an exemplary silane coupling agent molecule. [Formula 3]

Where Y represents a substituent, the substituent may be an alkyl group, an alkenyl group, an alkynyl group, an aryl group, a substituted or unsubstituted amine group, an alkoxy group, an aryloxy group, an epoxy group, a cycloalkoxy group, a hydroxyl group, or Halogen atom, etc.

The solvent includes, but is not limited to, at least one selected from the group consisting of methanol, ethanol, ethylene glycol, isopropyl glycol, propylene glycol, methyl cellosolve, tetracellulose, propylene glycol monomethyl ether, and the like Alcohol solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, ethyl lactate, etc., such as acetone, methyl Ketone solvents such as ethyl ketone, cyclopentanone, cyclohexanone, methylpentyl ketone, methyl isobutyl ketone, etc., such as pentane, hexane, heptane, etc. Non-chlorine aromatic solvents such as toluene, xylene, phenol, etc .; nitrile solvents such as acetonitrile, etc .; ether solvents such as tetrahydrofuran, dimethoxyethane, etc .; and chlorine systems such as chloroform, chlorobenzene, etc. Aliphatic hydrocarbon solvents.

In some embodiments, the adhesive layer 108 which is a pressure-sensitive adhesive layer may further include other appropriate additives, such as an antistatic agent, according to actual product requirements. The antistatic agent is, for example, (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salt, pyridinium, primary amino group, secondary amino group, and tertiary amino group; (b) having sulfonic acid base, sulfate base, and phosphoric acid Anionic antistatic agents based on anionic groups such as ester bases and phosphonic acid bases; (c) Amphoteric antistatic agents such as amino acids and aminosulfates; (d) amino alcohols, glycerols, and polyethylene glycols And other nonionic antistatic agents; (e) Polymer-type antistatic agents obtained by quantifying the above-mentioned antistatic agents with high molecular weight.

According to some embodiments, the polarizing plate 100 may further include a surface protection layer 110 and a release layer 112. The surface protection layer 110 is disposed on a side of the second protection layer 106 opposite to the polarizing base layer 102. The release layer 112 is disposed on a side of the adhesive layer 108 opposite to the first protective layer 104. The surface protective layer 110 and the release layer 112 may include, but are not limited to, at least one selected from the group consisting of polyesters such as polyethylene terephthalate, polyethylene naphthalate, and the like Resin, olefin resin, cellulose acetate resin, polycarbonate resin, acrylic resin such as polymethyl methacrylate (PMMA), etc., polybutylene terephthalate (PET), polyethylene (PE), polymer Propylene (PP), and cycloolefin resins.

According to some embodiments, the polarizing plate 100 may further include a first adhesive layer 114 and a second adhesive layer 116. The first adhesive layer 114 is disposed between the first protective layer 104 and the polarizing base layer 102 and is used to bond the first protective layer 104 and the polarizing base layer 102. The second adhesive layer 116 is disposed between the second protective layer 106 and the polarizing base layer 102 and is used for bonding the second protective layer 106 and the polarizing base layer 102. The first adhesive layer 114 and / or the second adhesive layer 116 may be a transparent adhesive layer made of an aqueous adhesive, wherein the material of the adhesive includes polyvinyl alcohol powder. Alternatively, the first adhesive layer 114 and / or the second adhesive layer 116 may also be an ultraviolet curing adhesive, such as an ultraviolet curing resin. According to some embodiments, the first adhesive layer 114 and / or the second adhesive layer 116 may include a silane coupling agent. This silane coupling agent may be the same as the foregoing and also meet the relationship of 2.5 <Z <40, preferably 4 <Z <28.6, and more preferably 12.5 <Z <20.

Before the polarizer is officially sold, it is usually necessary to perform a high temperature and high humidity aging test to confirm the weather resistance of the polarizer. In a high-temperature and high-humidity test environment, as shown in Figure 1, the molecules contained in each layer may move and even diffuse into other layers. For example, the molecules 104m contained in the first protective layer, such as molecules of additives, may diffuse into the adhesive layer 108 and further react with the molecules 108m contained in the adhesive layer.

When an additive having an aromatic heterocyclic ring is used in the adhesive layer, an additive molecule having an aromatic heterocyclic ring may have a planar structure due to a high temperature and high humidity environment. By using a silane coupling agent in the adhesive layer and adjusting the ratio of the content of the silane coupling agent to the content of the additive, the planar structure can be made to form a hydrogen bond with the three-dimensional silane coupling agent, as shown in Figure 2 Show. In this way, even if a reaction occurs, a planar structure that is easy to be stacked and crystals are not formed, and the weather resistance and visual effect of the polarizing plate can be ensured. In contrast, if such adjustments are not made, the planar structure formed by the aromatic heterocyclic ring is likely to form hydrogen bonds with the planar molecules contained in the adhesive layer, and is combined into a planar structure, as shown in FIG. 3. Such a planar structure is prone to stacking, and further crystals are precipitated, as indicated by arrow 202 in FIG. 4.

Specific experimental examples and comparative examples are provided below to explain the effect of adjusting the content of the additive / content of the silane coupling agent, that is, Z.

[Manufacture of protective layer]

Take additives with different weight fractions / cellulose triacetate / dichloromethane, mix and stir the three. After the stirring is complete, stand for degassing. After the degassing is completed, coat it on a stainless steel plate, followed by 60 ° C to 100 ° C Add 60 seconds to 120 seconds to dry and solidify to make a protective layer with different additive content.

[Manufacturing of adhesive layer]

100 parts by weight of acrylic resin is a copolymer obtained by taking a mixture of main agent molecules, such as a suitable monomer composition of methyl (meth) acrylate and the like, in a mixture of 90-99.99% and 0.01-10% of an unsaturated monomer having a polar functional group. Add 0.01 ~ 5 parts by weight of cross-linking agent; add 0.02 ~ 0.10 parts by weight of an appropriate silicon compound such as vinyltrimethoxysilane; add to an organic solvent and stir and mix. After allowed to stand for defoaming a coated film from the upper surface at a temperature of 50 ^o C ~ 150 ^oC obtained is heated for 60 to 300 seconds after drying and curing the adhesive layer have different silane-coupling agent content. The coating method includes, for example, a bar coating method, a blade coating method, a roll coating method, a plate coating method, a die coating method, a gravure coating method, and the like. The release film may be a polyethylene terephthalate (PET) film that has undergone a release treatment, or other suitable films.

[Manufacture of samples]

The protective layer and the adhesive layer are corona-treated. After that, both the protective layer and the adhesive layer are affixed to each other, and then bonded to the alkali-free glass.

[Sample Weathering Test]

The sample was put into a constant temperature and humidity oven, and the temperature and humidity conditions were 85 degrees / 85%, and the aging test was performed for 1000 hours.

[Crystal observation]

VH-Z100R optical microscope (Keyence manufacturer) was used to observe the aging test sample for the occurrence of crystals.

[Additive content detection]

After obtaining the standard with the supplier, dilute the solution to a certain rate, and then use a gas chromatography mass spectrometer (GC-MS, AGILENT) to complete the calibration line. Then, use the protective layer provided by the supplier to completely use a specific solvent. After dissolution, analysis was performed to confirm the content of the additive relative to the protective layer.

[Detection of Silane Coupling Agent]

Take an adhesive layer with a weight of about 0.2g and put it in 10 ml of nitric acid, and then perform microwave digestion and dissolution. After digestion, take a predetermined amount of water and dilute to 25 ml. Then use an inductively coupled plasma spectrometer (PERKIN ELMER) to measure the silicon content to obtain the Si content in the adhesive layer.

[Result discussion]

Table 1 lists the experimental results of several experimental examples and comparative examples. It can be seen that the value defining the content of the additive / the content of the silane coupling agent is equal to Z, and when 2.5 <Z <40, no crystals are precipitated. [Table 1]

In summary, by using a silane coupling agent in the adhesive layer and adjusting the value of the content of the additive / the content of the silane coupling agent, it is possible to avoid deterioration of weather resistance and visual effects caused by crystallization. In addition, since the additives in the protective layer may also move toward one side of the polarizing base layer, using a silane coupling agent in the adhesive layer for bonding the protective layer and the polarizing base layer can further improve the weatherability of the polarizing plate.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

100‧‧‧ polarizing plate
102‧‧‧Polarized base layer
104‧‧‧first protective layer
104m‧‧‧ Molecules contained in the first protective layer
106‧‧‧Second protective layer
108‧‧‧ Adhesive layer
Molecule contained in 108m‧‧‧adhesive layer
110‧‧‧ surface protection layer
112‧‧‧Release layer
114‧‧‧first adhesion layer
116‧‧‧Second adhesive layer
200‧‧‧ arrow

FIG. 1 is a schematic diagram of a polarizing plate according to an embodiment. FIG. 2 is a schematic diagram showing the structure of an additive molecule derived from a protective layer and a silane coupling agent molecule combined into a bulk structure according to an embodiment. FIG. 3 is a schematic view showing that the additive molecules from the protective layer and the planar molecules of the adhesive layer are combined into a planar structure according to the comparative example. FIG. 4 is a microstructure photograph of the crystals obtained by combining the additive molecules from the protective layer and the planar molecules of the adhesive layer into a planar structure according to the comparative example.

Claims (10)

A polarizing plate includes: a polarizing substrate layer; a first protective layer and a second protective layer, respectively disposed on two sides of the polarizing substrate layer, wherein the first protective layer includes an additive, and the additive has an aromatic compound. A ring; and an adhesive layer disposed on a side of the first protective layer opposite to the polarizing substrate layer, wherein the adhesive layer includes a silane coupling agent; wherein a content of the additive is defined / a The value of the content is equal to Z, 2.5 <Z <40. The polarizing plate according to item 1 of the scope of patent application, wherein the aromatic heterocyclic ring is a single-membered ring, a double-membered ring or a three-membered ring. The polarizing plate according to item 1 of the scope of patent application, wherein the aromatic heterocyclic ring includes at least one selected from the group consisting of a furan ring, a thiophene ring, a pyrrole ring, an azole ring, an isoxazole ring, A thiazole ring, an isothiazole ring, an imidazole ring, a pyrazole ring, a furfuryl ring, a triazole ring, a pyran ring, a pyridine ring, a pyridine ring, and a pyrimidine ring. The polarizing plate as described in item 1 of the scope of patent application, wherein the silane coupling agent includes at least one selected from the group consisting of vinyltrimethoxysilane, 3-methacryloxypropyltrimethyl Oxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N -(2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and 3-chloro Propyltrimethoxysilane. The polarizing plate according to item 1 of the patent application scope, wherein the adhesive layer includes: a main agent; a cross-linking agent; an adhesion promoter including the silane coupling agent; and a solvent. The polarizing plate according to item 5 of the scope of patent application, wherein the main agent includes at least one selected from the group consisting of: (meth) acrylate, (meth) acrylate, (formaldehyde) Base) butyl acrylate, 2-ethylhexyl (meth) acrylate, hydroxyethyl acrylate, 3-hydroxypropyl acrylate, hydroxyethyl methacrylate, 3-hydroxypropyl methacrylate, 4- Hydroxybutyl, 4-hydroxybutyl methacrylate, allyl alcohol, itaconic acid, acrylamide, cyanoethyl methacrylate, cyanoethyl acrylate, and 6-hydroxyethyl methacrylate. The polarizing plate according to item 5 of the scope of patent application, wherein the cross-linking agent includes at least one selected from the group consisting of an epoxy-based cross-linking agent, an isocyanate-based cross-linking agent, and an imine-based cross-linking agent. Crosslinking agent. The polarizing plate as described in item 5 of the patent application scope, wherein the solvent includes at least one selected from the group consisting of methanol, ethanol, ethylene glycol, isopropyl glycol, propylene glycol, and methylcellulose (methyl cellosolve), Dingcellulose, propylene glycol monomethyl ether, ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, ethyl lactate, acetone, methyl ethyl Ketone, cyclopentanone, cyclohexanone, methylpentyl ketone, methyl isobutyl ketone, pentane, hexane, heptane, toluene, xylene, phenol, acetonitrile, tetrahydrofuran, dimethoxyethane, Chloroform, and chlorobenzene. The polarizing plate as described in item 1 of the patent application scope, wherein the adhesive layer is a pressure-sensitive adhesive layer. The polarizing plate according to item 1 of the scope of patent application, further comprising: a first adhesive layer disposed between the first protective layer and the polarizing base layer, for bonding the first protective layer and the polarizing base layer And a second adhesive layer disposed between the second protective layer and the polarizing base layer for bonding the second protective layer and the polarizing base layer; wherein the first adhesive layer and / or the second adhesive layer The layer includes a polyvinyl alcohol powder, or a UV curable glue, or a silane coupling agent.