TW201527461A - Adhesive composition and composite polarization plate using the same - Google Patents

Abstract

Disclosed are an adhesive composition, including: a photo-polymerizable compound including a styrene monomer having a secondary amino group; and a photo-polymerization initiator, thereby when the composite polarizing plate is fabricated by combining the polarizer with the patterned retardation layer using the adhesive composition of the present invention, adhesion between the polarizer and the patterned retardation layer is remarkably improved, and the adhesive composition has excellent thermal resistance and moist heat resistance, as well as improved 3D stereoscopic effects, and a composite polarizing plate using the same.

Description

Subsequent composition and composite polarizing plate using the same

The present invention relates to an adhesive composition and a composite polarizing plate using the same.

In general, display devices for obtaining stereoscopic images, such as liquid crystal display devices, often include a patterned retardation film. Such a patterned retardation film has a certain technical configuration in which the optical axes of the individual pattern regions are formed in different directions from each other to transmit the independent image to the right eye and the left eye of the observer wearing the polarized glasses, thereby embodying three dimensions (ie, Stereo) image.

The patterned retardation film is generally prepared by forming an alignment layer on a glass substrate and applying liquid crystal to the alignment film to obtain alignment efficiency. The photosensitive liquid crystal material is aligned on the alignment layer and then crosslinked by light irradiation such as UV light to form a polymer liquid crystal film. The polymer liquid crystal film thus formed can function as a retarder pattern according to the alignment direction of the liquid crystal to which the surface of the alignment layer is attached.

The patterned retardation film is generally attached to one surface of the polarizing plate by an adhesive or an adhesive, and has been attached to one surface of the polyvinyl alcohol polarizer in recent years in order to reduce the thickness and weight of the display device.

When the adhesion between the patterned retardation film and the polarizing plate or the polarizer is reduced, deformation may occur during handling or use in the manufacturing process. In addition, the appearance of peeling or pushing phenomenon may cause concern when exposed to heat and humidity for a long period of time. In addition, typical polyethylene polarizers can shrink in the direction of stretching, and thus involve different delays in the position of the retarding film, which inevitably degrade the 3D stereoscopic effect.

Therefore, there is still a need to develop such as hot water resistance, heat and humidity resistance, etc., and excellent A modified adhesive of various efficiencies.

A method of preparing a film patterned retarder, a film patterned retarder, and a polarizing plate, and an image display device including the same are disclosed in Korean Patent Laid-Open Publication No. 2013-0028881.

Accordingly, it is an object of the present invention to provide an adhesive composition capable of significantly improving the relationship between the polarizer and the patterned retardation layer when used to fabricate a composite polarizing plate by combining a polarizer and a patterned retardation layer. Follow-up.

Another object of the present invention is to provide a composite polarizing plate which is subsequently produced by using an adhesive composition.

The above object of the present invention is achieved by the following features: The above objects of the present invention will be achieved by the following features:

(1) An adhesive composition comprising: a photopolymerizable compound comprising a styrene monomer having a secondary amine group; and a photopolymerization initiator.

(2) The composition according to the above (1), wherein the styrene monomer having a secondary amine group is represented by the following formula 1:

(wherein R ₁ is a hydrogen atom or a methyl group; R ₂ is an alkylene group having 1 to 5 carbon atoms which may be cleaved by a nitrogen atom; and R ₃ is an alkyl group or a benzyl group having 1 to 5 carbon atoms It may be cleaved by an oxygen atom and substituted with or without a hydroxyl group or an amine group, or may be bonded to R ₂ to form a ring having 4 to 6 carbon atoms).

(3) The composition according to the above (1), wherein the styrene monomer having a secondary amine group is included in an amount of 10% by weight or more based on the total weight of the monomers.

(4) The composition according to the above (1), wherein the photopolymerizable compound further comprises a non-polar styrene monomer in an amount of from 0% by weight to 5% by weight based on the total weight of the monomers.

(5) The composition according to the above (1), wherein the photopolymerizable compound further comprises a styrene monomer having a polar group other than an amine group in an amount of from 0% by weight to 85% by weight based on the total mass of the monomers.

(6) The composition according to the above (1), wherein the photopolymerization initiator is at least one selected from the group consisting of acetophenone-based, benzophenone, and 9-oxo-sulfur A radical photopolymerization initiator of a group consisting of thioxanthone, benzoin and benzoin alkyl ether.

(7) A composite polarizing plate comprising a polarizer; and a patterned retardation layer using the adhesive composition according to any one of the above (1) to (6) and then onto one surface of the polarizer.

(8) The polarizing plate according to (1) above, wherein the polarizer comprises a film having a protective film function or a film having a function of a retardation film on an opposite surface to a surface on which the patterned retardation layer is attached.

(9) The polarizing plate according to (7) above, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer having a benzene ring.

(10) The polarizing plate according to (7) above, wherein a peeling strength between the polarizer and the patterned retardation layer is 2.0 N/25 mm or 2.0 N/25 mm or more.

(11) The polarizing plate of (7) above, wherein the patterned retardation layer does not include an alignment layer.

(12) An image display device comprising the composite polarizing plate according to (7) above.

When the polarizer and the patterned retardation layer are combined to form a composite polarizing plate by using the adhesive composition of the present invention, the between the polarizer and the patterned retardation layer is remarkably improved. Follow-up.

The composite polarizing plate produced by using the adhesive composition of the present invention has excellent heat resistance and moist heat resistance, thereby suppressing occurrence of peeling and pushing even if it is exposed to heat and humidity for a long period of time.

The composite polarizing plate produced by using the adhesive composition of the present invention can have both polarizing performance and improved 3D stereoscopic effect.

The present invention discloses an adhesive composition comprising: a photopolymerizable compound including a styrene monomer having a secondary amine group; and a photopolymerization initiator to be combined by using the adhesive composition of the present invention When the patterned retardation layer and the polarizer are used to manufacture the composite polarizing plate, the adhesion between the polarizer and the patterned retardation layer is remarkably improved, and the adhesive composition has excellent heat resistance and moist heat resistance and is improved. 3D stereo effect, and the use of his composite polarizer.

Hereinafter, the present invention will be described in more detail.

Adhesive composition

The adhesive composition of the present invention may include a photopolymerizable compound including a styrene monomer having a secondary amine group.

If the adhesive composition of the present invention is used to combine a polarizer and a patterned retardation layer, the adhesive composition has excellent adhesion, and the improved adhesion can enhance heat resistance and moist heat resistance. The reason for these results is considered to be because the styrene monomer according to the present invention has an amine group, and the amine group and the polar group on the surface of the polarizer and the other polar group contained in the liquid crystal coating layer of the patterned retardation layer The bonds are joined to form a hydrogen bond, and the benzene ring contained in the styrene monomer is bonded to the benzene ring contained in the liquid crystal coating layer of the patterned retardation layer to perform a π bond interaction.

In addition, it is believed that the π bond interaction between the benzene ring contained in the styrene monomer and the benzene ring contained in the liquid crystal coating layer of the patterned retardation layer may also cause such results.

In the case of a styrene monomer having a primary amine group, since an amine group reacts with a ketone functional group to form an imine, photoinitiation may be reduced, and thus photocuring efficiency may be deteriorated.

The styrene monomer having a secondary amino group is not particularly limited but may include, for example, a monomer represented by the following formula 1:

(wherein R ₁ is a hydrogen atom or a methyl group; R ₂ is an alkylene group having 1 to 5 carbon atoms which may be cleaved by a nitrogen atom; and R ₃ is an alkyl group or a benzyl group having 1 to 5 carbon atoms It may be cleaved by an oxygen atom and substituted with or without a hydroxyl group or an amine group, or may be bonded to R ₂ to form a ring having 4 to 6 carbon atoms).

More specifically, the styrene monomer having a secondary amino group may include, for example, those represented by the formula a-1 to the formula a-5, which may be used singly or in combination of two or more kinds thereof.

[Formula a-2]

The content of the styrene monomer having a secondary amino group is not particularly limited as long as the above effects can be exhibited, and may be included, for example, in an amount of 10% by weight to 100% by weight based on the total weight of the monomers. If the content is within the above range, it is possible to exhibit excellent adhesion between the polarizer and the patterned retardation layer.

The photopolymerizable compound according to the present invention may further include a styrene monomer which is generally used in the related art and which does not contain an amine group, within a range not affecting the object of the present invention.

The styrene monomer not containing an amine group may include a non-polar styrene monomer, a styrene monomer having a polar group other than an amine group, or the like.

The non-polar styrene monomer improves the heat and humidity resistance.

The type of the non-polar styrene monomer is not particularly limited but may include, for example, styrene Alkene, vinyl toluene, α-methylstyrene, dimethylstyrene, t-butylstyrene or the like. These materials may be used singly or in combination of two or more kinds thereof.

The content of the non-polar styrene monomer is not particularly limited but may be included, for example, in an amount of from 0% by weight to 5% by weight based on the total weight of the monomers. If the content of the non-polar styrene monomer exceeds 5 wt%, the heat resistance may be slightly deteriorated.

The type of the styrene monomer having a polar group other than the amine group is not particularly limited, but may include, for example, a halogen atom, a hydroxyl group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, an alkoxy group having 1 to 6 carbon atoms, Styrene of cyano or the like. These styrenes may be used singly or in combination of two or more kinds thereof.

The content of the styrene monomer having a polar group other than the amine group is not particularly limited but may be included, for example, in an amount of from 0% by weight to 85% by weight based on the total weight of the monomers. If the content of the styrene monomer having a polar group other than the amine group exceeds 85 wt%, the adhesion may be slightly deteriorated.

The adhesive composition of the present invention may further comprise a photopolymerization initiator.

The photopolymerization initiator used herein is not particularly limited but may be, for example, based on acetophenone, benzophenone, 9-oxo-sulfur A free radical photopolymerization initiator of a substance of benzoin, benzoin alkyl ether or the like. These photopolymerization initiators may be used singly or in combination of two or more kinds thereof.

More specifically, the photopolymerization initiator may include, for example, acetophenone, hydroxydimethylacetophenone, dimethylaminoacetophenone, dimethoxy-2-phenylacetophenone, 3-methyl Phenylpropanone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 4-chloropropiophenone, 4,4-dimethoxy Acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4-hydroxycyclobenzophenone, 1-hydroxycyclohexanone, 2-methyl-1-[4-( Methylthio)phenyl]-2-(N-morpholinyl)-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2-propyl)one, two Benzophenone, p-phenylbenzophenone, 4,4-diaminobenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, anthraquinone ), 2-methylindole, 2-ethylhydrazine, 2-tert-butylhydrazine, 2-aminopurine, 2-methyl-9-oxosulfur 2-ethyl-9-oxosulfur 2-chloro-9-oxosulfur 2,4-dimethyl-9-oxosulfur 2,4-diethyl-9-oxosulfur , benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, benzyl dimethyl ketal, diphenyl ketone benzyl dimethyl ketal, acetophenone dimethyl a ketal, p-dimethylamino benzoate, 2,4,6-trimethylbenzimidyl diphenylphosphine, hydrazine, triphenylamine, carbazole or the like, but is not limited thereto .

Products marketed on the market may include, for example, darocur 1173, darocur 4265, darocur BP, darocur TPO, darocur MBF, iragacure 184, ilgacure 500, ilgacure 2959, ilgacure 754, ilgacure 651, ilgacure 369, ilgacure 907, ilgacure manufactured by SIBA Corporation. 1300, ilgacure 819, ilgacure 2022, irgacure 819DW, ilgacure 2100, ilgacure 784, ilgacure 250 or the like. These products may be used singly or in combination of two or more kinds thereof.

The content of the photopolymerization initiator is not particularly limited, but may be, for example, in the range of 0.1 part by weight to 10 parts by weight, and preferably 0.1 to 5 parts by weight to 100 parts by weight of the photopolymerizable compound. If the content of the photopolymerization initiator is less than 0.1 parts by weight, the curing rate is decreased and the curing progress may be insufficient, and when the content thereof exceeds 10 parts by weight, the durability of the subsequent layer may be deteriorated.

Composite polarizer

Further, the present invention provides a composite polarizing plate manufactured using the above adhesive composition.

The composite polarizing plate of the present invention may comprise a polarizer and a patterned retardation layer by an adhesive composition followed by a surface of the polarizer.

The composite polarizing plate of the present invention can have a high adhesion because the polarizer and the patterned retardation layer are combined using the above-described adhesive composition. In this regard, as described above, the adhesive composition layer can form a hydrogen bond with the polarizer while performing hydrogen bonding, a guanamine bond, and a π bond interaction together with the patterned retardation layer.

As long as the polarizer is generally used in the display field and the incident light can be polarized, the polarized light The device is not subject to specific restrictions. For example, a product produced by dyeing a polyvinyl alcohol (PVA)-based film with iodine or a dichroic dye, followed by stretching the dyed film in a desired direction may be used. A film having a protective film function or a film having a function of a retardation film may be applied to the opposite surface of the surface on which the retardation layer is patterned.

The configuration of the patterned retardation layer is not particularly limited but may include any configuration generally used in the related art. For example, the substrate, alignment film, and liquid crystal coating may be laminated in this order to form a layered structure. Additionally, the structure may not include an alignment film.

The retardation layer can then be patterned to allow the liquid crystal coating to face the polarizer.

The substrate is not particularly limited as long as the substrate is made of a material having excellent characteristics such as transparency, mechanical strength, thermal stability, moisture barrier properties, uniformity in retardation, isotropic properties, or the like. For example, a substrate made of at least one selected from the group consisting of polyolefin resin, polyester resin, cellulose resin, polycarbonate resin, acryl-based resin, styrene resin, vinyl chloride resin, ruthenium may be used. Amine resin, quinone imine resin, polyether oxime resin, oxime resin, polyether ether oxime resin, polyether ether ketone resin, polyphenylene sulfide resin, vinyl alcohol resin, vinylidene chloride resin, vinyl butyral resin, olefin Propyl resin, acetal resin and epoxy resin.

When the patterned retardation layer includes an alignment layer, the alignment layer can be applied to the substrate by applying a composition for forming an alignment layer (which is generally used in the related art) to provide alignment characteristics, and then pattern the coating to Formed with different alignment directions.

Methods for providing alignment characteristics can include, for example, rubbing, photoalignment, etc., and the patterning process can include a multiple exposure process using a light mask. However, the method and/or the patterning method for providing the alignment characteristics is not particularly limited.

The light for exposure is not particularly limited but may include, for example, polarized UV light radiation, ion beam or plasma beam radiation at a desired angle, illumination, or the like. For example, polarized UV light radiation is preferably used.

The liquid crystal layer can be formed by applying a composition for forming a liquid crystal coating layer including a reactive liquid crystal monomer (RM) and generally used in the related art to an alignment layer, followed by crosslinking.

The RM is not particularly limited but may include any monomer generally used in the related art, and is preferably a monomer having a benzene ring.

When the patterned retardation layer does not include the alignment layer, the patterned retardation layer can be applied to the substrate without the alignment layer by applying the composition for forming the liquid crystal coating, and then exposed to simultaneously perform patterning and alignment. form.

In this case, the composition for forming the liquid crystal coating layer may further include any compound (such as a linear photopolymerizable polymer) which can be aligned by polarized UV light for alignment.

If the patterned retardation layer does not include the alignment layer, a thin film display having a smaller thickness than that in the case of including the alignment layer can be obtained.

The composite polarizing plate produced using the adhesive composition of the present invention can exhibit excellent adhesion between the polarizer and the patterned retardation layer. For example, the peel strength applied between the polarizer and the patterned retardation layer may be 2.0 N/25 mm or 2.0 N/25 mm or more, and preferably in the range of 3.0 N/25 mm to 5.0 N/25 mm.

Image display device

Further, the present invention provides an image display apparatus including the above composite polarizing plate.

The image display device is not particularly limited but may include, for example, a liquid crystal display device or a transflective liquid crystal display device for obtaining a stereoscopic image, a plasma display device, an organic EL display device, or the like.

The composite polarizing plate of the present invention can be provided at a position where the polarizing plate and the patterned retardation layer are generally laminated.

In the following, preferred specific examples are proposed to more specifically describe the invention. Of course However, the following examples are given to illustrate the invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the invention. Such changes and modifications are intended to be included within the scope of the appended claims.

Example Examples and comparative examples

The subsequent composition has been prepared using the compositions and levels of the different compositions listed in Table 1 below.

Experimental example

(1) Measuring the peel strength

A polyvinyl alcohol polarizer including a patterned retardation layer (MPR 32, DNP Corporation) and a triethylenesulfonated cellulose protective film on one surface thereof is placed to contact the liquid crystal coating layer, And the adhesive composition prepared in each of the examples and the comparative examples was applied to the liquid crystal coating layer by means of a roll laminator. For evaluation, the end portion of the laminate was not coated with an adhesive composition.

Thereafter, UV irradiation was performed using a UV exposure device (FUSION Corporation) to irradiate UV light at a wavelength of 313 nm at a light amount of 2000 mJ/cm ² to cure the adhesive composition.

After cutting such a composite polarizing plate manufactured as described above into a sample having a width of 25 mm, the sample was subjected to peeling at a peeling rate of 300 mm/min, peeling in a 180° peeling direction, and then the peeling strength was measured.

(2) Evaluation of heat resistance and heat and humidity resistance

A composite polarizing plate was produced according to the same procedure as described in Experimental Example (1). After the propylene-based adhesive is applied to the protective film and the other is cured, the cured film is attached to the soda-based glass and subjected to autoclave treatment.

Then, the heat resistance and the heat and humidity resistance test of the respective composite polarizing plates were carried out.

After the treated film was kept at 80 ° C for 500 hours and at 60 ° C for 90 hours at 90% RH, it was investigated whether bubbles were generated or formed on the subsequent surface between the polarizer and the liquid crystal coating. Peel off. The results of the study were used to evaluate heat resistance and heat and humidity resistance according to the following evaluation criteria.

◎: No blistering or peeling was observed

○: blistering or peeling was observed in a very small area

△: slight blistering or peeling was observed.

X: Visually easy to observe blistering or flaking in a relatively large area

Referring to Table 2 above, the composite polarizing plates prepared in Examples 1 to 14 were confirmed to have extremely high peeling strength and increased durability by excellent heat resistance and moist heat resistance.

However, it was confirmed that the composite polarizing plates prepared in Comparative Example 1 to Comparative Example 5 had extremely low peeling strength and extremely low durability by a plurality of bubbles and peeling generated during evaluation of heat resistance and heat and humidity resistance.

Claims (12)

An adhesive composition comprising: a photopolymerizable compound comprising a styrene monomer having a secondary amine group; and a photopolymerization initiator. The composition of claim 1, wherein the styrene monomer having a secondary amine group is represented by the following formula 1: (wherein R ₁ is a hydrogen atom or a methyl group; R ₂ is an alkylene group having 1 to 5 carbon atoms which may be cleaved by a nitrogen atom; and R ₃ is an alkyl group or a benzyl group having 1 to 5 carbon atoms It may be cleaved by an oxygen atom and substituted with or without a hydroxyl group or an amine group, or may be bonded to R ₂ to form a ring having 4 to 6 carbon atoms). The composition of claim 1, wherein the styrene monomer having a secondary amine group is included in an amount of 10% by weight or more based on the total weight of the monomers. The composition of claim 1, wherein the photopolymerizable compound further comprises a non-polar styrene monomer in an amount of from 0% by weight to 5% by weight based on the total weight of the monomers. The composition of claim 1, wherein the photopolymerizable compound further comprises a styrene monomer having a polar group other than an amine group in an amount of from 0% by weight to 85% by weight based on the total weight of the monomers. The composition of claim 1, wherein the photopolymerization initiator comprises at least one selected from the group consisting of acetophenone-based, benzophenone, and 9-oxo-sulfur A radical photopolymerization initiator of a group consisting of thioxanthone, benzoin and benzoin alkyl ether. A composite polarizing plate comprising: a polarizer; and a patterned retardation layer using an adhesive composition as disclosed in any one of claims 1 to 6 to a surface of the polarizer. The polarizing plate of claim 7, wherein the polarizer comprises a film having a protective film function or a film having a function of a retardation film on an opposite surface of the surface to which the patterned retardation layer is attached. The polarizing plate of claim 7, wherein the patterned retardation layer comprises a liquid crystal coating layer containing a reactive liquid crystal monomer having a benzene ring. The polarizing plate of claim 7, wherein the peeling strength between the polarizer and the patterned retardation layer is 2.0 N/25 mm or 2.0 N/25 mm or more. The polarizing plate of claim 7, wherein the patterned retardation layer does not include an alignment layer. An image display device comprising the composite polarizing plate of claim 7 of the patent application.