KR20080112020A - Cured resin composition and prism film for prism layer formation - Google Patents

Abstract

The present invention is an ultraviolet curable polyfunctional (meth) acrylate monomer (A) represented by the following general formula (1), a urethane (meth) acrylate monomer (B) represented by the following general formula (2), a (meth) acrylate monomer for viscosity control (C) and the cured resin composition for prism layer formation of the prism film containing a polymerization initiator (D) is provided.

 (Formula 1)

 (Formula 2)

Description

Curable Resin Composition and Prism Film for Prism Layer Formation

The present invention relates to a cured resin composition for forming a prism layer and a prism film.

Japanese Patent Application Laid-Open No. 174910/1995 discloses a prism sheet for improving the front brightness of a backlight unit used in a liquid crystal display device. The prism sheet is molded into a specific shape from a transparent material having a specific refractive index. In the method of manufacturing a prism sheet, the patent proposes a method of integrally molding using a transparent glass having a specific range of refractive index and a method of molding a prism shape from the UV curable resin composition. As recognized by Japanese Patent Application Laid-Open No. 174910/1995, the plastic material represented by the UV curable resin can be used only in a limited use for applications requiring heat resistance. That is, if a representative lens sheet of a prism sheet obtained from a conventional UV curable resin is used in a high temperature environment, part of the lens sheet is fused on the surface of the backlight, leaving a sticky trace. This is a fatal flaw that adversely affects the optical performance of the product. Moreover, attention has been paid to liquid crystal display elements using plastic films as substrates instead of glass substrates in view of producing thinner and larger liquid crystal cells having curved display surfaces. However, when a plastic film is used as the substrate, the outer surface of the substrate is easily damaged, damaging its appearance, causing irregular reflections, and being damaged. This adversely affects the optical characteristics of the liquid crystal display device. For this reason, a coating layer of a UV curable resin is provided on the surface of the substrate to increase the hardness of the substrate surface, thereby obtaining a liquid crystal display device in which the surface is hardly damaged.

However, if the coating layer is formed using a conventional UV curable resin, the obtained image is darker than the image obtained from the liquid crystal display device using the glass substrate due to insufficient transparency, light coloring resistance, etc., and the quality is degraded.

 In order to improve the above disadvantages of the prior art, the present invention is excellent in viscosity, high in productivity, high in transparency, high in refractive index of the cured product, high in surface hardness, and excellent in adhesion, as well as good curling properties, and shredding phenomenon. An object of this is to provide a less cured resin composition for forming a prism layer.

The present invention for achieving the above object, the ultraviolet curable polyfunctional (meth) acrylate monomer (A) represented by the following formula (1), the urethane (meth) acrylate monomer (B) represented by the formula (2), viscosity control It provides the cured resin composition for prism layer formation of the prism film containing the (meth) acrylate monomer (C) for this, and a polymerization initiator (D).

 (Formula 1)

(R is a hydrogen atom or an alkyl group of 1 to 10 carbon atoms, X is a hydrogen atom or a methyl group of 1 to 10 carbon atoms, n is an integer of 1 to 20)

 (Formula 2)

(Wherein, X is an aliphatic or aromatic hydrocarbon containing or not containing 7 to 80 carbon atoms containing 2 to 10 (meth) acrylate functional groups, and R is an aliphatic or aromatic hydrocarbon containing from 1 to 10 carbon atoms. 15 aliphatic or aromatic hydrocarbons)

In addition, the (meth) acrylate monomer (C) for viscosity control is a (meth) acrylate monomer having a refractive index of 1.5 or more and a viscosity of 50 cps to 2000 cps at 25 ° C., the curing for forming a prism layer of a prism film It provides a resin composition.

In addition, the (meth) acrylate monomer (C) for viscosity adjustment is benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxy From the group consisting of cipropyl (meth) acrylate, neopentyl glycol benzoate (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and o-phenylphenoxyethanol (meth) acrylate It provides at least one cured resin composition for forming a prism layer of the prism film, characterized in that at least one selected.

5 to 50 parts by weight of the compound of component (A), 5 to 50 parts by weight of the compound of component (B), 20 to 60 parts by weight of component (C) and 0.1 to 5 parts by weight of component (D). It provides the cured resin composition for prism layer formation of the prism film characterized by the above-mentioned.

The present invention also provides a prism film comprising a prism layer formed of the above-described composition on one surface of the transparent base film.

The present invention also provides a backlight unit comprising the above-described prism film.

The present invention also provides a liquid crystal display device comprising the above-described backlight unit.

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

The cured resin composition for prism layer formation of the prism film of this invention is an ultraviolet curable polyfunctional (meth) acrylate monomer (A) represented by following formula (1), and the urethane (meth) acrylate monomer (B) represented by following formula (2) And a (meth) acrylate monomer (C) for viscosity control, and a polymerization initiator (D).

First, the ultraviolet curable polyfunctional (meth) acrylate monomer (A) represented by following formula (1) is included.

(Formula 1)

(R is a hydrogen atom or an alkyl group of 1 to 10 carbon atoms, X is a hydrogen atom or a methyl group of 1 to 10 carbon atoms, n is an integer of 1 to 20)

The (meth) acrylate represented by the formula (1) is a high refractive index material having a refractive index of 1.58 or more to maintain the high refractive index of the prism layer after curing, thereby improving the brightness and hardness after curing, in particular, the prism film to increase adhesion to the base film It is preferable as a substance which forms the prism layer of.

The epoxy (meth) acrylate (A) is preferably contained 5 to 50 parts by weight with respect to 100 parts by weight of the composition, when less than 5 parts by weight, it is difficult to meet the expectation of improving the refractive index and adhesion, more than 50 parts by weight In one case, there is a high possibility of cracking due to lack of flexibility due to excessive increase in hardness.

In addition, the ultraviolet curing monomer further includes a urethane (meth) acrylate (B) represented by the following formula (2).

(Formula 2)

(Wherein, X is an aliphatic or aromatic hydrocarbon containing or not containing 7 to 80 carbon atoms containing 2 to 10 (meth) acrylate functional groups, and R is an aliphatic or aromatic hydrocarbon containing from 1 to 10 carbon atoms. 15 aliphatic or aromatic hydrocarbons).

Urethane acrylate represented by the formula (2) has a self-restoring power is preferred as a material to improve the yield of the film by reducing the acid separation phenomenon to reduce workability and defective rate.

The urethane acrylate is also described in more detail as a trimer isocyanate, based on isocyanurate, allophanate, adduct isocyanate, for example hexamethylene diisocyanate, or isophorone diisocyanate, toluene Examples of trimers such as diisocyanate include commercially available toluene diisocyanate adducts such as N3300N, N3300A, BASF HI 100, HA 100, TPA 100, 24A-100, etc. of BAISA Corporation. The urethane acrylate with strong self-resilience can be synthesize | combined by reacting the (meth) acrylate containing a hydroxyl group with such trifunctional isocyanate. Examples of the acrylate having a hydroxyl group include 2-hydroxy ethyl (meth) acrylate, 2-hydroxy propyl (meth) acrylate, 4-hydroxy butyl (meth) acrylate, and caprolactone modified hydroxy (meth) acrylate. It provides at least one (meth) acrylate selected from the group consisting of a cured resin composition for forming a prism layer of the prism film.

The urethane (meth) acrylate (B) is preferably contained 5 parts by weight to 50 parts by weight with respect to 100 parts by weight of the composition, less than 5 parts by weight is not likely to be due to self-resilience, more than 50 parts by weight Difficult to adjust viscosity

In order to be able to maintain the viscosity of the composition of the present invention to a suitable level, further comprising a (meth) acrylate monomer (C) for viscosity control, solubility in the ultraviolet curable (meth) acrylate monomer (A) This excellent thing is preferable, and it is a monomer having a viscosity low enough to lower the composition viscosity after dissolution, and may further include (meth) acrylate having a refractive index of 1.50 or more and a viscosity at 25 ° C. of 50 to 2000 cps or less. Specific examples thereof include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, 2-hydroxy-3-phenoxy propyl (meth) acrylate, neopentyl glycol benzoate It is preferable that it is at least 1 sort (s) of monomer chosen from the group which consists of (meth) acrylate, 2-hydroxy-3- phenoxypropyl (meth) acrylate, and o-phenylphenoxy ethanol (meth) acrylate.

The (meth) acrylate monomer (C) for the viscosity control is preferably included 20 to 60 parts by weight based on 100 parts by weight of the composition, when less than 20 parts by weight, it is difficult to expect the effect of sufficient viscosity reduction, 60 weight In the case of a negative excess, there is a problem in that hardness and refractive index are lowered.

The photoinitiator (D) is characterized in that at least one selected from the group consisting of phosphine oxide (phospine oxide), propane (propanone), ketone (ketone), formate (formate) photoinitiator.

The photoinitiator preferably contains 0.1 to 5 parts by weight based on 100 parts by weight of the composition. If the amount is less than 0.1 parts by weight, sufficient photocuring is not achieved, and a blocking phenomenon occurs. If the amount is more than 5 parts by weight, photoinitiators remain after curing, and thus surface precipitation of residual photoinitiators occurs when left for a long time.

In addition to the above materials, antioxidants, ultraviolet absorbers, light stabilizers, thermal polymerization inhibitors, labelling agents, surfactants, lubricants, and the like may be used together in the cured resin composition for forming the prism layer.

The polymerizable compositions described herein may be advantageous for other optical materials such as microstructure-containing optical articles (eg films). Exemplary Optical Materials Optical lenses, such as Fresnel lenses, optical films, such as high refractive index films, such as microrepeated films, such as fully internal reflective films, or light-enhanced films, planar films, multilayer films, retroreflective sheets, optical fibers Or optical tubes and the like.

The present invention also provides a prism sheet having a prism shape formed by curing the composition. The configuration of the prism sheet is not limited and may employ a structure known in the art.

The manufacturing method is as follows. The composition may be coated on a transparent optical polymer substrate such as polyethylene terephthalate (hereinafter referred to as PET) or polycarbonate, or on a film in which a water-dispersed polyurethane layer is coated on the substrate in a primer form of 1 to 2 μm, and the thickness of the film Is about 10 to 1000 µm, and preferably 50 to 300 µm is used. Coating method can be applied to gravure coating, roll coating, life coating and the like.

Coating thickness is 1-200 micrometers normally, Preferably it is 10-100 micrometers, More preferably, it is 20-50 micrometers. UV light irradiation amount is about 0.1 ~ 2J / cm ^2, preferably 0.4 ~ 0.8J / cm ² and wavelength of it is better to use a metal halide lamp in the series to 365nm as the primary wavelength.

In the case of forming the prism layer by curing using the resin composition as described above, the curing speed is high, the productivity is excellent, and the film produced after curing has no curling phenomenon, high brightness and less breakage of shape, color change and It was excellent in yellowing resistance, adhesion with film, and good releasability with polymer mold.

The present invention also provides a backlight device for a liquid crystal display device having the prism sheet. The backlight device is not limited and may employ a structure known in the art. For example, a light diffusion plate, a prism sheet, or the like may be provided on a light guide plate for guiding light of a light source and a light source such as an LED, and an upper surface of the light guide plate. It is preferable that the said prism sheet is a prism sheet mentioned above.

The present invention will be further illustrated by the following examples, which are only specific examples of the present invention, and are not intended to limit or limit the protection scope of the present invention.

411 parts by weight of N3300 (Buyer) and 453 parts by weight of FA2D (Dacel) which is caprolactone modified hydroxy acrylate As a laurate and polymerization inhibitor, 0.4 weight part of methoxy hydroquinone was used. The reaction was carried out at 75 ° C. for 4 hours, and the reaction was completed at the point where 2265 cm ⁻¹ , an isocyanate characteristic peak of the infrared spectrum, was completely extinguished. Synthesized urethane acrylate had a refractive index of 1.499 and viscosity of 12,000 cps at 25 ° C.

As an embodiment of the composition of the present invention, each composition and composition ratio are shown in Table 1 below.

<Table 1>

ingredient Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 UV Curing Monomer UV Curing Monomer (A) 17 10 5 27 34 37 UV Curing Monomer (B) 27 34 39 17 10 7 UV Curing Monomer (C) 53 53 53 53 53 53 45 55 High refractive monomer (a) 42 32 High refractive monomer (b) 10 10  Photoinitiator 1-hydroxycyclohexyl phenyl propanone 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Oligo 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propano-1-non 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5

UV curing monomer (A): phenol novolac epoxy acrylate

UV curing monomer (B): urethane acrylate prepared in Synthesis Example 1

UV curing monomer (C): phenoxyethyl acrylate

High refractive monomer (a): bisphenol A glycidyl ether acrylate

High refractive monomer (b): acryloyl morpholine

Evaluation methods for the above examples are as follows.

(1) Viscosity Evaluation of Composition

The viscosity at 25 ^° C. was measured using a rotational viscometer according to JIS K7117.

(2) refractive index evaluation of the composition

The refractive index is measured using a refractometer (model name: 1T, Japan ATAGO ABBE) to measure the refractive index of the composition. The light source for the measurement was a D-beam sodium lamp of 589.3 nm.

(3) Adhesive force evaluation (falling number / 100)

After coating the composition on the transparent PET base film, applying a pressure to the thickness of 3㎛ by superimposing a smooth metal plate on the surface, and then cured to remove the metal plate, only 100 of the cured thickness within the area of 10 × 10 ㎜ After the incision into the matrix structure, the number of stripped matrices is indicated while adhering the tape thereon and strongly releasing vertically.

(4) mountain separation

After mounting the coated film on the 17-inch backlight unit as shown in No. 2, the backlight unit is mounted on a device that reciprocates 60 times per minute and reciprocates for 10 hours. If it is very bad, if it is 7-9 places, if it is bad, if it is 4-6 places, if it is 1 ~ 3, it is good, if not, it is classified as good.

(4) pencil hardness

The pencil hardness test was performed using a pencil hardness tester (PHT, manufactured by Seokbo Science, Korea) under a 500g load. The pencil was made 5 times per pencil hardness using Mitsubishi products. If there were two or more gases, it was determined to be defective.

Kiss: 0 OK

Kiss: 1 OK

Ges: 2 or more NG

(6) curling

The sample cut into the square shape of A4 size (29.7 X 21.0 cm) was placed on a flat glass plate with the coated surface of the film facing up, and the distance from the square glass plate was measured at 25 ° C. and 50% RH, and then averaged. Was taken as a measured value.

Very good: 0 to 15 mm, good: 15 to 30 mm, poor: 30 to 50 mm, very poor: more than 50 mm.

The results evaluated by the evaluation result method described above the composition of the Example is shown in Table 2 below.

<Table 2>

Example Comparative example One 2 3 4 5 6 One 2 Viscosity (cps / 25 ^o C) 864 755 632 541 940 764 692 562 Refractive index 1.534 1.541 1.544 1.547 1.551 1.549 1.536 1.531 Adhesion 0/100 0/100 0/100 0/100 0/100 0/100 0/100 3/100 Mountain crossing Very good Very good Very good Good Good Bad Bad Bad Pencil hardness 2H 2H 2H 2H 2H 2H 2H 1H curling Very good Very good Good Good Good Good Bad Very bad

The present invention is a high refractive index composition, which has a viscosity characteristic that is easy to form the prism layer of the prism film, the surface hardness after the formation of the prism film and adhesion to the base film is improved, the cured resin composition for forming a prism layer excellent in brightness To provide.

Claims (7)

UV-curable polyfunctional (meth) acrylate monomer (A) represented by the following formula (1), urethane (meth) acrylate monomer (B) represented by the following formula (2), (meth) acrylate monomer (C) for viscosity control And a cured resin composition for forming a prism layer of a prism film comprising a polymerization initiator (D).  (Formula 1)

(R is a hydrogen atom or an alkyl group of 1 to 10 carbon atoms, X is a hydrogen atom or a methyl group of 1 to 10 carbon atoms, n is an integer of 1 to 20)  (Formula 2)

(Wherein, X is an aliphatic or aromatic hydrocarbon containing or not containing 7 to 80 carbon atoms containing 2 to 10 (meth) acrylate functional groups, and R is an aliphatic or aromatic hydrocarbon containing from 1 to 10 carbon atoms. 15 aliphatic or aromatic hydrocarbons) The prism of the prism film according to claim 1, wherein the (meth) acrylate monomer (C) for viscosity control is a (meth) acrylate monomer having a refractive index of 1.5 or more and a viscosity of 50 cps to 2000 cps at 25 ° C. Cured resin composition for layer formation. The (meth) acrylate monomer (C) for adjusting viscosity is benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, 2-hydroxy 3-phenoxypropyl (meth) acrylate, neopentyl glycol benzoate (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate and o-phenylphenoxyethanol (meth) acrylate Cured resin composition for forming a prism layer of the prism film, characterized in that at least one selected from the group consisting of The method of claim 1, wherein 5 to 50 parts by weight of the compound of component (A), 5 to 50 parts by weight of the compound of component (B), 20 to 60 parts by weight of component (C) and 0.1 to 0.1 part of component (D). Cured resin composition for prism layer formation of the prism film characterized by including 5 weight part. A prism film comprising a prism layer formed of the composition of any one of claims 1 to 4 on one surface of the transparent base film. A backlight unit comprising the prism film of claim 5. A liquid crystal display device comprising the backlight unit of claim 6.