KR20180026184A - Coating layer and coating film having self-healing property - Google Patents

Abstract

The present invention relates to a coating film having a self-recovery property. More particularly, the present invention relates to the coating film having excellent self-recovery property while exhibiting high hardness.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a coating film having self-

The present invention relates to a coating film having magnetic restoration property. More particularly, the present invention relates to a coating film having excellent magnetic restoration characteristics while exhibiting high hardness.

In order to protect the product from damage due to mechanical, physical and chemical influences from the outside, various coating layers or coating films are applied to the surfaces of electric and electronic devices such as cellular phones, electronic material parts, home appliances, automobile interior and exterior, have. However, scratches on the coated surface of the product and cracks due to external impacts deteriorate the appearance characteristics, major performance and life of the product, and various studies are being conducted to protect the surface of the product to maintain the quality of the product for a long period of time.

Particularly, research and interest in coating materials having self-healing properties (SELF-HEALING) has been rapidly increasing in recent years. The self-restoration property refers to a property that, when external physical force or stimulus is applied to the coating layer, scratches or the like are formed on the coating layer, damage such as scratches is gradually healed or reduced Quot; Although a coating material exhibiting such a magnetic restoration characteristic and a mechanism of a magnetic restoration characteristic are variously known, a method of using a coating material exhibiting elasticity most commonly is known. That is, even if physical damages such as scratches are applied on the coating layer, the coating material may gradually lose the damage due to the elasticity of the coating material itself, thereby exhibiting the above-described magnetic restoration characteristics.

However, in the case of the conventional coating layer exhibiting such a magnetic restoration property, the mechanical properties of the coating layer such as hardness, abrasion resistance, or coating strength are insufficient due to the inclusion of an elastic material. In particular, when a coating layer showing magnetic restoration characteristics is applied to an outermost film that protects a display from the outside in a smart phone or the like, the mechanical and optical properties of the coating layer are required to be high. However, Most of them did not meet such high physical properties.

Due to the problems of the prior art, there is a continuing need for development of a technique that enables the provision of a coating layer or a coating film exhibiting excellent mechanical and optical properties together with excellent magnetic restoration characteristics for use in the outermost film applications of various display devices .

In order to solve the above problems, the present invention provides a coating film having excellent mechanical and optical properties while exhibiting magnetic restoration characteristics.

In order to solve the above problems,

A support substrate; And a coating layer formed on at least one side of the supporting substrate,

Wherein the coating layer comprises a photocurable resin having a magnetic restoration property; Wherein a difference (t-dmax) between a thickness (t) of the coating layer and a maximum particle diameter (dmax) of the organic filler is 1 占 퐉 or less and a refractive index of the organic filler Is not more than 0.1.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a coating film which is applied to surfaces of various home appliances, mobile devices, display devices and the like and exhibits improved mechanical and optical properties along with magnetic restoration characteristics.

The coating film has a magnetic restoration property against scratches caused by scratches or external impact, and can provide high surface hardness, flexural resistance, impact resistance and the like.

In addition, the above-mentioned coating film can secure high reproducibility and optical properties along with the above-described magnetic restoration characteristics. Therefore, it is possible to realize a bent or folded shape, so that it can be used not only in a flat film but also in a mobile device including a curved portion or in a flexible form, a display device, a front plate of various instrument panels, .

1 is a schematic view showing a cross section of a coating film according to an embodiment of the present invention.

The coating film of the present invention comprises a support substrate; And a coating layer formed on at least one side of the supporting substrate, wherein the coating layer comprises a photocurable resin having a magnetic restoring property; Wherein a difference (t-dmax) between a thickness (t) of the coating layer and a maximum particle diameter (dmax) of the organic filler is 1 占 퐉 or less and a refractive index of the organic filler Is not more than 0.1.

In the present invention, the terms first, second, etc. are used to describe various components, and the terms are used only for the purpose of distinguishing one component from another.

Moreover, the terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the present invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises", "comprising", or "having" are used to designate the presence of stated features, steps, components, or combinations thereof, and are not intended to preclude the presence of one or more other features, Components, or combinations thereof, as a matter of convenience, without departing from the spirit and scope of the invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

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

A coating film according to an embodiment of the present invention includes a support substrate; And a coating layer formed on at least one side of the supporting substrate, wherein the coating layer comprises a photocurable resin having a magnetic restoring property; Wherein a difference (t-dmax) between a thickness (t) of the coating layer and a maximum particle diameter (dmax) of the organic filler is 1 占 퐉 or less and a refractive index of the organic filler Is 0.1 or less.

First, the coating layer of the present invention includes a photocurable resin and an organic filler.

When a damage occurs such as a scratch or a crack is generated as a physical force or a stimulus is applied to a coating layer formed by curing of a coating composition, the damage is gradually healed or reduced And a self-healing coating material, which is a characteristic of the present invention, has been rapidly increasing in recent years.

In this specification, self-healing refers to a characteristic that the coating layer is restored to its original shape within a predetermined time without additional coating or surface treatment when the surface of the coating layer is damaged by scratching, etc. The surface of the coating layer is rubbed with a copper brush, The degree of recovery can be assessed by observing with the naked eye and measuring the time.

Coating materials and mechanisms that exhibit such magnetic restoration characteristics are well known.

However, there is a problem that the coating layer composed of only the coating material having the known magnetic restoration property has poor surface hardness, film strength and mechanical properties. In order to compensate for this, a method of incorporating inorganic fine particles such as silica in a coating layer has been proposed. However, in order to obtain a desired surface hardness, a large amount of inorganic fine particles must be added. As a result, a haze is generated due to a difference in refractive index between inorganic fine particles and a coating layer. The transparency is lowered and the elasticity of the coating layer is also lowered so that the magnetic restoration characteristic is lowered.

Thus, according to one embodiment of the present invention, not only a magnetic restoration characteristic can be realized by a coating layer including the photocurable resin having the magnetic restoration property and the organic filler satisfying the predetermined condition, Mechanical properties and excellent optical properties can be ensured, thus completing the present invention.

The coating film satisfying both the magnetic restoration property and the high hardness can be realized by optimizing the photocurable resin and the organic filler satisfying predetermined conditions.

1 is a schematic view showing a cross section of a coating film according to an embodiment of the present invention.

Referring to FIG. 1, a coating film 100 is formed on one side of a supporting substrate 10 and a supporting substrate 10, and includes a coating layer 20 including an organic filler 30.

At this time, the difference (t-dmax) between the thickness t of the coating layer 20 and the maximum particle diameter damx of the organic filler 30 is about 1 탆 or less, or about 0.5 탆 or less, and substantially t-dmax is 0 . That is, the coating layer 20 is formed to have a thickness substantially equal to the particle diameter of the organic filler 30. Thus, the organic filler 30 is dispersed in the photocurable resin, .

When the difference (t-dmax) between the thickness of the coating layer and the maximum particle diameter of the organic filler exceeds 1 占 퐉, the effect of improving the surface hardness by the organic filler is lowered and the coating layer of a certain thickness covers the upper part of the organic filler, The restoration characteristic may be degraded.

In the coating film of the present invention, the difference between the cured refractive index of the photocurable resin included in the coating layer and the refractive index of the organic filler is about 0.1 or less, or about 0.05 or less, or about 0.02 or less. The lower limit of the refractive index difference is preferably as low as possible, and is not particularly limited. For example, it may be 0 or more, or about 0.001 or more.

In the specification of the present invention, the cured refractive index means a refractive index measured in the state of a coating layer after the photocurable resin is substantially completely cured, and the curing refractive index of the photocurable resin and the refractive index of the organic filler are all nd25 (Refractive index of sodium D ray at 25 캜).

As described above, according to one embodiment of the present invention, by using the organic filler in which the difference between the thickness of the coating layer and the maximum particle diameter is 1 탆 or less and the difference in refractive index between the coating layer and the photo- A coating film having both high hardness and optical properties can be provided.

According to an embodiment of the present invention, the photocurable resin having the magnetic restoration property exhibits a magnetic restoration property due to elasticity, and is not particularly limited as long as it can be used for forming a coating film. However, (Meth) acrylate-based binder in the range of 1.60 to 1.60, preferably 1.40 to 1.55 can be used. More specific examples of such commercially available binders include Blemmer 占 TA-604AU (NOF corporation), RD-4047, RD-4048, RD-4951, RD-4953, RD-5250, RD-5300 and RD-5400 Aekyung Chemical).

According to one embodiment of the present invention, the average particle size of the organic filler may be about 5 to about 50 占 퐉, or about 5 to about 30 占 퐉, or about 5 to about 15 占 퐉. If the average particle diameter of the organic filler is less than 5 탆, the effect of improving the surface hardness of the organic filler may be deteriorated. If the average particle diameter of the organic filler is more than 50 탆, the thickness of the coating layer should also be increased. There is room.

According to an embodiment of the present invention, the organic filler is not particularly limited as long as it satisfies the maximum particle diameter, the average particle diameter and the refractive index as described above. For example, polystyrene, polymethylmethacrylate ), Polymethylacrylate, polyacrylate, polymethylacrylate-co-styrene, polymethylacrylate-co-styrene, polymethylmethacrylate- But are not limited to, polymethylmethacrylate-co-styrene, polycarbonate, polyvinylchloride, polybutyleneterephthalate, polyethyleneterephthalate, polyamide, Or polyimide may be used. More specific examples of commercially available organic fillers include cross-linked polymethylmethacrylates such as NIPPON SHOKUBAI MA1004, MA1006, MA1010, and the like.

For the formation of a uniform coating layer, the difference between the average particle diameter and the maximum particle diameter of the organic filler is preferably 2 탆 or less, or 1 탆 or less, or 0.5 탆 or less.

The content of the organic filler may be about 0.01 to about 5 parts by weight, or about 0.01 to about 2 parts by weight, or about 0.1 to about 1 part by weight, based on 100 parts by weight of the photocurable resin having the magnetic restoration property. If the content of the organic filler is too small, the effect of improving the hardness may be insufficient. If the content of the organic filler is too large, the coating layer may not be formed well or the self- From this point of view, the above-described weight range is preferable.

In the coating film of the present invention, the above-mentioned support base material is a transparent plastic resin for optical use so as to ensure flexibility and hardness, and can be used without any particular limitation on the production method and material of the support base material such as stretched film or non-stretched film.

The thickness of the support substrate may be at least about 20 microns, or at least about 25 microns, or at least about 30 microns, and the upper limit may be at most about 200 microns, or at most about 150 microns, or at most about 100 microns, Mu m or less. If the thickness of the supporting substrate is less than 20 占 퐉, there is a risk of fracture or curling in the coating layer forming process, and it may be difficult to achieve high hardness. On the other hand, if the thickness exceeds 200 탆, the flexibility may be deteriorated.

More specifically, according to one embodiment of the present invention, the supporting substrate may be formed of, for example, polyimide (PI), polyimideamide, polyetherimide (PEI), polyethyleneterephtalate (PET), polyethylene naphthalate (PEN), polyetheretherketone (PEEK), cyclic olefin polymer (COP), polyacrylate (PAC), polymethyl methacrylate polymethylmethacrylate (PMMA), triacetylcellulose (TAC), and the like. The supporting substrate may be a single layer or a multi-layer structure including two or more substrates made of the same or different materials as needed, and is not particularly limited.

The coating film of the present invention may include the coating layer only on one side of the supporting substrate or on both sides thereof.

The coating layer according to an embodiment of the present invention may be formed by photocuring a coating composition comprising a photocurable binder having magnetic restoring properties, an organic filler, other additives, and an organic solvent.

Examples of the photoinitiator include 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy- 1- [4- (2-hydroxyethoxy (2-benzoyl-2- (dimethylamino) -1- [4- (4-methylphenylsulfanyl) (4-morpholinyl) phenyl] -1-butanone, 2-methyl-1- [4- 6-trimethylbenzoyl) -phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. Products currently on the market include Irgacure 184, Irgacure 500, Irgacure 651, Irgacure 369, Irgacure 907, Darocur 1173, Darocur MBF, Irgacure 819, Darocur TPO, Irgacure 907 and Esacure KIP 100F. These photoinitiators may be used alone or in combination of two or more.

Examples of the organic solvent include alcohol solvents such as methanol, ethanol, isopropyl alcohol and butanol, alkoxy alcohol solvents such as 2-methoxyethanol, 2-ethoxyethanol and 1-methoxy-2-propanol, Ketone solvents such as ethyl ketone, methyl isobutyl ketone, methyl propyl ketone and cyclohexanone, propylene glycol monopropyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, Ether solvents such as diethylene glycol monomethyl ether, diethyl glycol monoethyl ether, diethyl glycol monopropyl ether, diethyl glycol monobutyl ether and diethylene glycol-2-ethylhexyl ether, benzene, toluene, The same aromatic solvent may be used alone or in combination.

The content of the organic solvent may be varied within a range that does not deteriorate the physical properties of the coating composition, so that the weight ratio of the solid content: organic solvent to the solid content of the components included in the coating composition is about 30: 70 to about 99: 1. And may have appropriate fluidity and applicability when the organic solvent is in the above range.

The coating layer of the present invention can be formed by applying and curing a coating composition further comprising additives commonly used in the art such as surfactants, yellowing inhibitors, leveling agents, antifouling agents and the like, in addition to the components described above have. The content thereof is not particularly limited as it can be adjusted in various ways within a range that does not deteriorate the physical properties of the composition.

According to one embodiment of the present invention, the thickness of the coating layer is adjusted according to the maximum particle diameter of the organic filler, and the difference between the thickness of the coating layer and the maximum particle diameter of the organic filler after being fully cured as described above is about 1 탆 or less, Or less.

The coating composition may be sequentially applied to the front and rear surfaces of the supporting substrate, or both surfaces of the supporting substrate at the same time.

According to one embodiment of the present invention, the coating film of the present invention can be obtained by coating a coating composition containing the above-mentioned components on both sides of the above-mentioned support substrate and then photo-curing to form a coating layer. In this case, the method of applying the coating composition is not particularly limited as long as it can be used in the art to which the present technology belongs. For example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, A gravure coating method, a comma coating method, a slot die coating method, a lip coating method, and a solution casting method.

As the light source that can be used in the light irradiation process for the photo-curing, various light sources known in the technical field of the present invention can be used. As a non-limiting example, a high-pressure mercury lamp, a metal halide lamp, a black light fluorescent lamp, or the like can be used.

According to an embodiment of the present invention, the coating film may include a plastic resin film, an adhesive film, a release film, a conductive film, a conductive layer, a liquid crystal layer, a coating layer, a cured resin layer, A non-conductive film, a metal mesh layer, or a layer such as a patterned metal layer, a film, or a film. Further, the layer, film, film or the like may be in any form of a single layer, a double layer or a laminate type. The layer, film, or film may be laminated on the coating layer by a method such as lamination, coating, deposition, or sputtering using an adhesive or an adhesive film. However, But is not limited thereto.

The coating film of the present invention exhibits excellent magnetic recovery properties, impact resistance, hardness, high strength, scratch resistance, high transparency, and high transmittance, and thus can be used in various fields. In other words, it exhibits excellent magnetic restoration property that restores itself even if damage such as scratches or cracks occurs due to an external stimulus, and exhibits excellent mechanical properties and plays a role of properly protecting the exterior of the various home appliances, display devices or molded products .

For example, the coating film of the present invention may have a pencil hardness of B or more, or H or more, measured under a load of 500 g in accordance with JIS K5400.

In addition, the coating film of the present invention may exhibit magnetic restoration characteristics in which scratches generated after rubbing with the copper on the surface of the coating layer are restored within 30 seconds, within 25 seconds, or within 20 seconds.

Further, the coating film of the present invention may have a light transmittance of about 90% or more, or about 91% or more. The upper limit of the light transmittance is preferably as high as possible, and is not particularly limited, but may be, for example, 99% or less, or about 98% or less, or about 95% or less.

In addition, the coating film of the present invention may exhibit a haze of about 2.0% or less, or about 1.5% or less, or about 1.2% or less. The lower limit of the haze is preferably as low as possible, so that it may be, for example, not less than 0%, not less than about 0.1%, or not less than about 0.2%.

Further, the coating film of the present invention may have an initial color b * (b * according to CIE 1976 L * a * b * color space) of about 1.0 or less, or about 0.5 or less, or about 0.3 or less.

The coating film of the present invention can be used in various fields. For example, attached to the exterior of various home appliances, or used as a cover substrate or a device substrate of a mobile communication terminal, a touch panel of a smart phone or a tablet PC, and various displays.

Best Mode for Carrying Out the Invention Hereinafter, the function and effect of the present invention will be described in more detail through specific examples of the present invention. It is to be understood, however, that these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention.

<Examples>

Example 1

0.5 part by weight of MA1010 (manufacturer: NIPPON SHOKUBAI, average particle diameter: 10 mu m, maximum particle diameter: 12 mu m) as an organic filler, and 0.5 part by weight of photo-initiator Irgacure 184 (trade name, manufactured by NOF corporation) as 100 parts by weight of Blemmer TA-604AU 6 parts by weight of Basf), 1 part by weight of Irgacure TPO (manufactured by Basf), and 100 parts by weight of PGMEA as a solvent Coating composition.

The coating composition was coated on one side of a polyethylene terephthalate substrate (trade name: A4300, thickness: 100 占 퐉) and photocured with a Fusion D-bulb lamp (light quantity: 50W) to form a coating layer.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.51, the refractive index of the organic filler was 1.51, and the thickness of the coating layer was 12 占 퐉.

Example 2

In Example 1, a coating film was formed in the same manner as in Example 1, except that the content of MA1010 was changed to 1 part by weight.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.51, the refractive index of the organic filler was 1.51, and the thickness of the coating layer was 12 占 퐉.

Example 3

In Example 1, a coating film was formed in the same manner as in Example 1, except that 100 parts by weight of RD-4047 (Aekyung Chemical) was used as a photocurable binder.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.49, the refractive index of the organic filler was 1.51, and the thickness of the coating layer was 12 占 퐉.

Example 4

In Example 3, a coating film was formed in the same manner as in Example 3, except that the content of MA1010 was changed to 1 part by weight.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.49, the refractive index of the organic filler was 1.51, and the thickness of the coating layer was 12 占 퐉.

Example 5

In Example 1, a coating film was formed in the same manner as in Example 1 except that 100 parts by weight of RD-5300 (Aekyung Chemical) was used as a photocurable binder.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.55, the refractive index of the organic filler was 1.51, and the thickness of the coating layer was 12 占 퐉.

Example 6

In Example 5, a coating film was formed in the same manner as in Example 5, except that the content of MA1010 was changed to 1 part by weight.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.55, the refractive index of the organic filler was 1.51, and the thickness of the coating layer was 12 占 퐉.

Comparative Example 1

In Example 1, a coating film was formed in the same manner as in Example 1, except that MA1010 was not used.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.51 and the thickness of the coating layer was 12 占 퐉.

Comparative Example 2

In Example 3, a coating film was formed in the same manner as in Example 3, except that MA1010 was not used.

As measured on the cured coating layer, the cured refractive index of the photocurable resin was 1.49 and the thickness of the coating layer was 12 占 퐉.

Comparative Example 3

In Example 5, a coating film was formed in the same manner as in Example 5, except that MA1010 was not used.

When measured in the cured coating layer, the cured refractive index of the photocurable resin was 1.55 and the thickness of the coating layer was 12 占 퐉.

<Experimental Example>

<Measurement method>

1) Pencil Hardness

Using a pencil hardness tester, the surface of the coating layer was reciprocated three times with a load of 500 g according to the measurement standard JIS K5400, and the hardness without scratches was confirmed.

2) Self restoration ability

The surface of the coating layer was coated with copper at a room temperature for 10 times under a load of 500 g The time of restoration of the scratches after rubbing was visually observed.

3) Transmittance and haze

The transmittance and haze were measured using a spectrophotometer (instrument name: COH-400).

4) Color b *

Color b * was measured using a spectrophotometer (instrument CM-5).

The results of the physical properties measurement are shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Pencil hardness H H H H H H 2B 2B 2B Self restoration ability 8 seconds 14 seconds 10 seconds 16 seconds 12 seconds 20 seconds 5 seconds 5 seconds 6 seconds Hayes 0.50% 0.51% 0.72% 1.13% 1.2% 1.58% 0.49% 0.30% 0.51% Transmittance 91.27% 91.31% 91.56% 91.50% 90.72% 90.05% 91.37% 91.50% 91.3% Color b * 0.29 0.30 0.25 0.26 0.42 0.25 0.27 0.23 0.25

Referring to Table 1, the film of the present invention exhibited good properties in all physical properties, and particularly exhibited a magnetic restoration ability in which scratches caused by high hardness and copper sol were restored within 30 seconds.

On the other hand, the films of the comparative examples had similar magnetic restoring ability but showed low pencil hardness.

Claims (7)

A support substrate; And a coating layer formed on at least one side of the supporting substrate,
Wherein the coating layer comprises a photocurable resin having a magnetic restoration property; Wherein a difference (t-dmax) between a thickness (t) of the coating layer and a maximum particle diameter (dmax) of the organic filler is 1 占 퐉 or less and a refractive index of the organic filler Is less than or equal to 0.1.
The coating film according to claim 1, wherein the photocurable resin having the magnetic restoration property is a curing resin of a polyfunctional urethane (meth) acrylate binder having a curing refractive index in a range of 1.30 to 1.60.
The method of claim 1, wherein the organic filler is selected from the group consisting of polystyrene, polymethylmethacrylate, polymethylacrylate, polyacrylate, polymethylacrylate-co styrene, polymethyl acrylate-co-styrene, polymethylmethacrylate-co-styrene, polycarbonate, polyvinylchloride, A coating film comprising at least one selected from the group consisting of polybutylene terephthalate, polyethyleneterephthalate, polyamide, and polyimide.
The coating film according to claim 1, wherein the content of the organic filler is 0.01 to about 5 parts by weight based on 100 parts by weight of the photocurable resin.
The coating film according to claim 1, wherein the average particle size of the organic filler is 5 to 50 占 퐉.
The coating film according to claim 1, wherein the coating layer exhibits a pencil hardness of H or higher at a load of 500 g.
The coating film of claim 1, wherein the coating film exhibits a haze of 2.0% or less and a color b * of 1.0 or less (b * by CIE 1976 L * a * b * color space).

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