KR101636583B1 - A Composition for Making Hard Coating Layer and Hard Coating Film Made by Using the Same - Google Patents

Abstract

The present invention relates to a composition for forming a hard coat layer of a hard coat film for display protection, and a hard coat film prepared therefrom, which comprises a urethane acrylate oligomer containing a chain extender as a main component of a composition for forming a hard coat layer, To a composition for forming a hard coat layer and a hard coat film which are improved in hardness, adhesiveness, flexural resistance and abrasion resistance of the film.

Description

[0001] The present invention relates to a composition for forming a hard coating layer and a hard coating film prepared therefrom (A Composition for Making Hard Coating Layer and Hard Coating Film Made Using the Same)

The present invention relates to a composition for forming a hard coat layer of a hard coat film for display protection and a hard coat film for display protection using the same.

A glass substrate used for various displays such as a television, a computer, a plasma display (PDP), a liquid crystal display (LCD) and the like has been fragile because of its low impact resistance. To overcome these drawbacks and protect the display, plastic films have been introduced and used.

As the plastic film for display protection, a plastic film having a hard coat layer coated with an active energy ultraviolet curable resin and having subjected to a surface treatment such as antireflection treatment or antistatic treatment has been used.

However, the display protective plastic film has a problem in that phenomena such as cracking and peeling of the hard coating layer due to curling and curling due to heat treatment accompanied with surface treatment appear.

The present invention provides a composition for forming a hard coat layer of a hard coat film for protecting various displays, and a composition for forming a hard coat layer which improves the hardness, adhesion, flexural resistance and abrasion resistance of the hard coat layer.

The present invention also provides a hard coat film comprising a composition for forming a hard coat layer having improved hardness, adhesiveness, flexural resistance and abrasion resistance.

Accordingly, the present invention provides, as a first preferred embodiment, a composition for forming a hard coating layer comprising a urethane acrylate oligomer, a photo-curable material other than a urethane acrylate oligomer, and a photopolymerization initiator, wherein the urethane acrylate oligomer comprises a chain extender Wherein the hard coat layer is formed on the surface of the hard coat layer.

The chain extender according to this embodiment may be selected from the group consisting of glycerin, trimethylol ethane, trimethylol propane and 1,2,6-hexane triol It can be selected.

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The content of the chain extender may be 2 to 6 wt%.

As a second preferred embodiment of the present invention, there is provided a hard coat film comprising a urethane acrylate oligomer, a photo-curing substance other than a urethane acrylate oligomer, and a composition for forming a hard coat layer made of a photopolymerization initiator, wherein the urethane acrylate oligomer has a chain The hard coat film is characterized in that it comprises an extender.

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

The present invention provides, as a preferred embodiment, a composition for forming a hard coat layer comprising a urethane acrylate oligomer, a photo-curable material other than a urethane acrylate oligomer, and a photopolymerization initiator, wherein the urethane acrylate oligomer comprises a chain extender .

Generally, the urethane acrylate oligomer is a UV curable resin used as an adhesive composition, which does not contain a benzene ring and shows no yellowing phenomenon, and thus is widely used for display coating applications.

In the composition for forming a hard coat layer according to the present invention, the content of each component is preferably 20 to 60 parts by weight of a photocurable substance other than the urethane acrylate oligomer, and the photopolymerization initiator It is preferably 3 to 10 parts by weight. If the content of the photocurable material is less than 20 parts by weight, hardness suitable for the hard coating layer can not be obtained. If the content of the photocurable material is more than 60 parts by weight, hardness of the hard coating layer is increased. When the amount of the photopolymerization initiator is less than 3 parts by weight, photopolymerization is not achieved and blocking phenomenon occurs. When the amount of the photopolymerization initiator is more than 10 parts by weight, there is no problem in curing. However, there is a problem that the initiator is precipitated on the surface during long- .

On the other hand, the photo-curable materials other than the urethane acrylate oligomer include dipentaerythritol pentaacrylate, trihydroxyethylisocyanurate triacrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) (Meth) acrylate, propylene oxide-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) (Meth) acrylate, dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (metha) acrylate, which is composed of tris (acryloxyethyl) isocyanurate, propionic acid-modified dipentaerythritol penta As the polyfunctional acrylate selected from the group It may be used in combination.

The photopolymerization initiator may be divided into a radical polymerization type photopolymerizable prepolymer or a photopolymerization initiator for a photopolymerizable monomer and a photopolymerization initiator for a cation polymerizable type photopolymerizable prepolymer. The photopolymerization initiator for the radically polymerizable photopolymerizable prepolymer or the photopolymerizable monomer may be at least one selected from the group consisting of benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin- , Acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) Phenyl-2 (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-aminothraxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethyl Tiok Wherein the photopolymerization initiator for the cationic polymerization type photopolymerizable prepolymer is a mixture of one or more selected from the group consisting of aromatic oxysulfonium Ion, aromatic iodonium ion and the like, and an anion such as tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, or the like. .

The urethane acrylate oligomer contained in the composition for forming a hard coat layer according to the present invention is characterized by containing a chain extender to improve the hardness of the hard coat layer. That is, the crosslinking degree and the molecular weight of the composition for forming a hard coating layer are increased by the chain extender, and the hardness of the hard coating layer can be improved.

The content of the chain extender is preferably 2 to 6% by weight based on 100% by weight of the urethane acrylate oligomer. When the content of the chain extender is less than 2% by weight, the increase in the degree of crosslinking for improving the hardness is low, If the content is more than 6% by weight, the gelation phenomenon occurs and it is difficult to control the hard coating film.

The chain extender may be an alcohol selected from the group consisting of glycerin, trimethylol ethane, trimethylol propane, and 1,2,6-hexane triol, , In particular, a trivalent alcohol or a tetravalent alcohol, among which trivalent alcohols are more preferable. They may be used alone or in combination of two or more.

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The urethane acrylate oligomer comprising the chain extender according to the present invention may be prepared by preparing an urethane prepolymer having an isocyanate terminal by using a polyhydric alcohol, a chain extender, a reaction catalyst, an aliphatic isocyanate, etc., And then reacting until the terminal isocyanate is completely consumed.

The composition for forming the hard coat layer may be prepared by mixing a urethane acrylate oligomer, a photo-curable material other than the urethane acrylate oligomer, and a photopolymerization initiator including the chain extender prepared as described above, with a solvent.

Examples of the solvent include alcohols such as methanol, ethanol, propanol and isopropanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate and ethyl acetate; aromatic compounds such as toluene, benzene and xylene; And the like, or a mixture of two or more thereof.

The hard coating film can be prepared by applying the composition for forming a hard coating layer prepared as described above on one side of the substrate layer and irradiating ultraviolet rays.

By applying the composition for forming a hard coat layer containing the urethane acrylate oligomer, the photo-curing substance and the photopolymerization initiator as described above, wherein the urethane acrylate comprises a chain extender, to the hard coat film, the hardness, adhesiveness, It is possible to provide a hard coating film excellent in abrasion resistance and capable of reducing curl by surface treatment.

In particular, the hardness of the hard coat film is evaluated by pencil hardness, and preferably 3H or more. This is because pencil hardness of 3H or more is required to impart scratch resistance to external contact or impact. For this reason, it is preferable that the hardness of the hard coat film of the present invention has a mechanical strength of 3H or more.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

urethane Acrylate Oligomer

≪ Synthesis Example 1 &

0.436 mol of pentaerythritol (Aldrich), 0.08 mol of trimethylol propane as a chain extender, and 0.03 g of dibutyltin dilaurate as a reaction catalyst were fed into a 1000-μl four-necked flask equipped with an oil bath, a thermometer, a reflux condenser and a dropping funnel, And the mixture was stirred for 30 minutes at room temperature for 30 minutes. 2.014 mol of hexamethylene diisocyanate was added in three steps at intervals of 1 hour, and the reaction was continued for 3 hours to prepare a urethane prepolymer having a terminal isocyanate group. At this time, the value of R (N = C = O / OH, ratio of isocyanate group to hydroxyl group) value of the urethane prepolymer having the terminal isocyanate is 1.91.

Then, to prevent thermal polymerization of the vinyl group, the temperature of the reactor was dropped to 50 캜, and 1.744 mol of hydroxyethyl acrylate was added thereto, and the mixture was stirred for 5 hours until the isocyanate group was completely consumed. Using the FT-IR spectrum, it was confirmed that there was no residual isocyanate with a characteristic peak of N = C = O in the vicinity of 2270 cm ^-1 , and the reaction was terminated to produce about 560 g of urethane acrylate oligomer.

≪ Synthesis Example 2 &

A urethane acrylate oligomer was prepared in the same manner as in Synthesis Example 1 except that 0.18 mol of trimethylolpropane as a chain extender was used.

≪ Synthesis Example 3 &

A urethane acrylate oligomer was prepared in the same manner as in Synthesis Example 1, except that 0.25 mol of trimethylolpropane as a chain extender was used.

≪ Synthesis Example 4 &

A urethane acrylate oligomer was prepared in the same manner as in Synthesis Example 1, except that 0.04 mol of trimethylolpropane, which is a chain extender, was used.

≪ Synthesis Example 5 &

A urethane acrylate oligomer was prepared in the same manner as in Synthesis Example 1, except that 0.33 mol of trimethylolpropane as a chain extender was used.

≪ Synthesis Example 6 &

A urethane acrylate oligomer was prepared in the same manner as in Synthesis Example 1 except that the chain extender was not used.

≪ Synthesis Example 7 &

A urethane acrylate oligomer was prepared in the same manner as in Synthesis Example 1, except that dipentaerythritol was used instead of pentaerythritol and no chain extender was used.

≪ Synthesis Example 8 &

A urethane acrylate oligomer was prepared in the same manner as in Synthesis Example 1, except that tripentaerythritol was used instead of pentaerythritol, and a chain extender was not used.

Hard coating layer  Composition for forming

≪ Example 1 >

33.3 parts by weight of dipentaerythritol pentaacrylate (Donga Synthesis, M-402), 30.3 parts by weight of trihydroxyethyl isocyanurate triacrylate (manufactured by Eastman Chemical Co., Ltd., M -315), 5 parts by weight of 1-hydroxycyclohexyl phenyl ketone as a photopolymerization initiator and 234 parts by weight of methyl ethyl ketone as a solvent were mixed at 60 DEG C for 1 hour to prepare a composition for forming a hard coat layer.

≪ Example 2 >

A composition for forming a hard coat layer was prepared in the same manner as in Example 1, except that the urethane acrylate oligomer obtained in Synthesis Example 2 was used.

≪ Example 3 >

A composition for forming a hard coat layer was prepared in the same manner as in Example 1, except that the urethane acrylate oligomer obtained in Synthesis Example 3 was used.

≪ Comparative Example 1 &

A composition for forming a hard coat layer was prepared in the same manner as in Example 1, except that the urethane acrylate oligomer obtained in Synthesis Example 4 was used.

≪ Comparative Example 2 &

A composition for forming a hard coat layer was prepared in the same manner as in Example 1 except that the urethane acrylate oligomer obtained in Synthesis Example 5 was used.

≪ Comparative Example 3 &

A composition for forming a hard coat layer was prepared in the same manner as in Example 1, except that the urethane acrylate oligomer obtained in Synthesis Example 6 was used.

≪ Comparative Example 4 &

A composition for forming a hard coat layer was prepared in the same manner as in Example 1, except that the urethane acrylate oligomer obtained in Synthesis Example 7 was used.

≪ Comparative Example 5 &

A composition for forming a hard coat layer was prepared in the same manner as in Example 1 except that the urethane acrylate oligomer obtained in Synthesis Example 8 was used.

Hard coating  film

<Example 4>

The composition for forming a hard coat layer prepared in Example 1 was applied to one surface of polyethylene terephthalate (KOLON, thickness 188 탆) as a base layer, dried in an oven at 80 캜 for 3 minutes, and irradiated with ultraviolet light / Cm &lt; 2 &gt;) to form a hard coating film (thickness 200 mu m) by irradiating 500 mJ / cm &lt; 2 &gt;

&Lt; Example 5 >

A hard coat film was prepared in the same manner as in Example 4 except that the composition for forming a hard coat layer prepared in Example 2 was used.

&Lt; Example 6 >

A hard coat film was prepared in the same manner as in Example 4 except that the composition for forming a hard coat layer prepared in Example 3 was used.

&Lt; Comparative Example 6 >

A hard coat film was prepared in the same manner as in Example 4, except that the composition for forming a hard coat layer prepared in Comparative Example 1 was used.

&Lt; Comparative Example 7 &

A hard coat film was prepared in the same manner as in Example 4 except that the composition for forming a hard coat layer prepared in Comparative Example 2 was used.

&Lt; Comparative Example 8 >

A hard coat film was prepared in the same manner as in Example 4 except that the composition for forming a hard coat layer prepared in Comparative Example 3 was used.

&Lt; Comparative Example 9 &

A hard coat film was prepared in the same manner as in Example 4 except that the composition for forming a hard coat layer prepared in Comparative Example 4 was used.

&Lt; Comparative Example 10 &

A hard coat film was prepared in the same manner as in Example 4 except that the composition for forming a hard coat layer prepared in Comparative Example 5 was used.

The hard coating films prepared in the above Examples and Comparative Examples were evaluated as follows. The results are shown in Table 1.

(1) Pencil Hardness

The hard coating films prepared in the Examples and Comparative Examples were measured for hardness using a pencil hardness tester of IMOTO, Japan.

[Measuring conditions]

a. Speed of 30mm / min

b. The loads are 500gf and 750gf

c. Japan's IMOTO pencil hardness tester

(2) scratch resistance

When the hard coating films of the examples and comparative examples were subjected to a minimum pressure using the basis weight of a Big Heart test apparatus manufactured by IMOTO, Japan, the occurrence of scratches on the hard coat film was measured. The degree of damage caused by scratches was judged by naked eyes and the criteria were as follows.

Poor scratch resistance ← X <Δ <○ <◎ → excellent scratch resistance

division
Thickness
(탆) Pencil hardness Scratch resistance
Load 500gf Load 750gf Example 4 200 3H 3H ◎ Example 5 200 3H 3H ◎ Example 6 200 3H 3H ◎ Comparative Example 6 200 2.8H 3H ◎ Comparative Example 7 200 3H 3H ◎ Comparative Example 8 200 2.5H 3H ◎ Comparative Example 9 200 2.5H 3H ○ Comparative Example 10 200 2H 2H ○

As a result of the physical property evaluation, the hard coating films of Examples 4 to 6 of the present invention were found to have excellent hardness and scratch resistance. In particular, when the hardness is measured, the hardness when the load is 500 gf or 750 gf is all 3H, and it can be expected that the excellent physical strength required as a protective film for protecting the display can be secured.

On the other hand, the hard coating film of Comparative Example 6 having a lower content of trimethylolpropane as a chain extender than the hard coating films of Examples 4 to 6 was found to have a low hardness. In Examples 4 to 6 The hard coating film of Comparative Example 7 having a higher content of trimethylolpropane as a chain extender than the hard coating film of Comparative Example 6 had the same hardness but the gelation phenomenon occurred at the time of manufacture, there was.

In addition, the hard coating films according to Comparative Examples 8 to 10 have lower hardness and scratch resistance than the hard coating films according to Examples 4 to 6, so that they are less optimally used .

Therefore, the hard coat film prepared using the composition for forming a hard coat layer containing a urethane acrylate oligomer can be applied as a display protective film requiring strength, and in particular, it is possible to use a urethane acrylate oligomer containing a chain extender It was found that the hard coating films of Examples 4 to 6 were optimum.

Claims (5)

A photocurable coating composition for display protection comprising:
20 to 60 parts by weight of a polyfunctional acrylate which is a photocurable substance based on 100 parts by weight of the urethane acrylate oligomer, and 3 to 10 parts by weight of a photopolymerization initiator,
The urethane acrylate oligomer is prepared by preparing an urethane prepolymer having an isocyanate end by using a polyhydric alcohol, a chain extender, a reaction catalyst, and an aliphatic isocyanate, adding an acrylate compound to the isocyanate, However,
Wherein the chain extender is contained in an amount of 2 to 6 wt% based on the total weight of the urethane acrylate oligomer.
The method of claim 1, wherein the chain extender is selected from the group consisting of glycerin, trimethylol ethane, trimethylol propane, and 1,2,6-hexane triol. Lt; RTI ID = 0.0 &gt; 1, &lt; / RTI &gt;
delete delete A hardcoat film comprising a hardcoat layer formed from the composition of claim 1 or 2.