JP6406563B1 - Hard coat film and method for producing the same - Google Patents

Abstract

The present invention provides a hard coat film having excellent adhesion (particularly adhesion over time) to a hard coat layer when a cycloolefin polymer film is used as a substrate.
In this hard coat film, a hard coat layer containing an ionizing radiation curable resin is laminated on at least one surface of a cycloolefin polymer base film via a primer layer. The arithmetic average surface roughness (Ra) of this primer layer is in the range of 0.5 nm to 15.0 nm, and the static friction coefficient of the surface of this primer layer is in the range of 0.6 to 2.0.
[Selection figure] None

Description

  The present invention relates to a hard coat film used for an optical member and a method for producing the same. More specifically, the present invention relates to a hard coat film that can be used as a protective film for panel devices such as electroluminescence (EL) display devices, liquid crystal display devices (LCD) and plasma display devices, and display device parts such as touch panels.

  For example, a display surface of a liquid crystal display such as a liquid crystal display device (LCD) is required to be provided with scratch resistance so that the surface is not damaged due to scratches during handling. Therefore, it is common practice to impart scratch resistance to the display surface of a display using a hard coat film in which a hard coat layer is provided on a base film. In recent years, with the widespread use of touch panels that allow data and instructions to be input by touching with a finger, pen, or the like while viewing the display on a display screen, functional requirements for hard coat films used for such optical members are further increasing.

By the way, since the cycloolefin polymer film is excellent in transparency, heat resistance, dimensional stability, low hygroscopicity, low birefringence, and optical isotropy as a base film, it is used for such optical member applications. Therefore, it has been proposed to provide a hard coat layer on this cycloolefin film. However, since this cycloolefin polymer film has a small number of polar groups on the film surface unlike an acrylic film or a polyester film, when the cycloolefin polymer film is used as a substrate, the adhesion with the hard coat layer is inferior. There was a point.
Therefore, conventionally, methods for imparting easy adhesion with a hard coat layer to a cycloolefin polymer film are disclosed in Patent Document 1, Patent Document 2, and the like.

JP 2001-147304 A JP 2006-110875 A

  Conventionally, as a method for imparting easy adhesion with a hard coat layer to a cycloolefin polymer film, Patent Document 1 discloses corona treatment, plasma treatment, ultraviolet irradiation treatment, and the like. There was a problem that the adhesion between the polymer film and the hard coat layer was insufficient, and in particular, adhesion failure with time was likely to occur.

Patent Document 2 discloses a method of coating an anchor coating agent made of an olefin resin on a cycloolefin polymer film. This anchor coat treatment improves the adhesion between the cycloolefin polymer film and the hard coat layer to some extent, but is still insufficient, and there is a problem that adhesion failure with time tends to occur. Furthermore, there is a problem that cracks are likely to occur on the surface of the hard coat layer under heat resistant conditions. Even when such an anchor coating treatment of a specific material was performed, the improvement in the adhesion between the base film and the hard coat layer was insufficient.
Therefore, in the conventional hard coat film, improvement of the adhesion with the hard coat layer, particularly the temporal adhesion, when the cycloolefin polymer film is used as a base material has been a major issue.

Therefore, an object of the present invention is to provide a hard coat film excellent in adhesiveness with a hard coat layer, particularly adhesive with time, using a cycloolefin polymer film as a base material, and a method for producing the same.

As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by having the following configuration.
That is, the present invention has the following configuration.

(First invention)
A hard coat film in which a hard coat layer containing an ionizing radiation curable resin is laminated on at least one surface of a cycloolefin polymer-based substrate film via a primer layer, the arithmetic average surface roughness of the primer layer ( Ra) is in the range of 0.5 nm to 15.0 nm, and the static friction coefficient of the surface of the primer layer is in the range of 0.6 to 2.0.

(Second invention)
The hard coat film according to the first invention, wherein a ratio of a static friction coefficient to a dynamic friction coefficient (static friction coefficient / dynamic friction coefficient) on the surface of the primer layer is 2.5 or less.

(Third invention)
The hard coat film according to the first or second invention, wherein the primer layer has a surface free energy of 22 mN / m or more.

(Fourth invention)
The hard coat film according to any one of the first to third inventions, wherein a contact angle of water on the surface of the primer layer is 110 degrees or less.

(Fifth invention)
Any of the first to fourth inventions, wherein the hard coat layer contains, as the ionizing radiation curable resin, a polyfunctional acrylate having three or more (meth) acryloyloxy groups in one molecule. Hard coat film according to crab.

(Sixth invention)
A method for producing a hard coat film having a hard coat layer containing an ionizing radiation curable resin on a cycloolefin polymer-based substrate film via a primer layer, the cycloolefin polymer-based substrate film, The arithmetic average surface roughness (Ra) of the primer layer obtained by applying and drying the primer layer paint is in the range of 0.5 nm to 15.0 nm, and the static friction coefficient of the surface of the primer layer is 0.00. Then, a hard coat layer coating containing an ionizing radiation curable resin is applied on the primer layer, dried to form a hard coat layer, and then irradiated with ionizing radiation. The manufacturing method of the hard coat film characterized by the above-mentioned.

(Seventh invention)
The method for producing a hard coat film according to the sixth invention, wherein a ratio of a static friction coefficient to a dynamic friction coefficient on the surface of the primer layer (static friction coefficient / dynamic friction coefficient) is 2.5 or less.

According to the present invention, it is possible to obtain a hard coat film excellent in adhesion with a hard coat layer, in particular, adhesion over time, using a cycloolefin polymer film as a substrate.

Hereinafter, although the form for implementing this invention is demonstrated in detail, this invention is not limited to the following embodiment.
In the present specification, “XX to ΔΔ” means “from XX to ΔΔ” unless otherwise specified.

As in the first invention, the hard coat film of the present invention has a hard coat layer containing an ionizing radiation curable resin laminated on at least one surface of a cycloolefin polymer-based substrate film via a primer layer. It is a hard coat film, the arithmetic average surface roughness (Ra) of the primer layer is in the range of 0.5 nm to 15.0 nm, and the static friction coefficient of the surface of the primer layer is 0.6 to 2.0. It is the range of these.
Hereinafter, the configuration of the hard coat film will be described in detail.

[Base film]
First, the base film of the hard coat film will be described.
In the present invention, a cycloolefin polymer film excellent in transparency, heat resistance, dimensional stability, low hygroscopicity, low birefringence, optical isotropy and the like is used as the base film of the hard coat film. Specifically, cycloolefin units are polymerized alternately or randomly in the polymer skeleton and have an alicyclic structure in the molecular structure, and include norbornene compounds, monocyclic cyclic olefins, cyclic conjugated dienes and vinyl fatty acids. A cycloolefin copolymer film or a cycloolefin polymer film, which is a copolymer comprising at least one compound selected from cyclic hydrocarbons, can be selected and used as appropriate.

  In the present invention, the thickness of the cycloolefin polymer film is appropriately selected depending on the application, but in the range of 10 μm to 300 μm from the viewpoint of mechanical strength, handling properties, thinning of the display device, and the like. It is preferable that it is in the range of 20 μm to 200 μm.

  In addition, regarding the heat resistance of the cycloolefin polymer film, when used for a hard coat film, the thermogravimetry (TG) method or differential scanning calorimetry for measuring the thermal change when a temperature change is applied to the sample. The use of a film having a glass transition temperature measured by the (DSC) method or the like of about 120 ° C to 170 ° C is preferred.

  In the present invention, when a hard coat layer is formed on one side of the cycloolefin polymer film via a primer layer, the cycloolefin polymer film is wound on the back surface of the cycloolefin polymer film on which no hard coat layer is formed. Polyethylene resin and polypropylene, which are excellent in releasability from cycloolefin polymer film by co-extrusion method when forming cycloolefin polymer film, for the purpose of preventing film crimping and improving film runnability when forming a hard coat layer It is good also as a film which laminated | stacked resin or polyester resin as a protective layer. Moreover, it is also possible to use what stuck protective films, such as a polyethylene resin in which the weak adhesion layer is formed in the back surface, a polypropylene resin, or a polyester resin.

  Examples of the cycloolefin polymer film include commercially available ZEONOR (trade name: manufactured by ZEON CORPORATION), Optica (trade name: manufactured by Mitsui Chemicals), Arton (trade name: manufactured by JSR Corporation), Examples include Kozek (trade name: Kurashiki Boseki Co., Ltd.).

[Primer layer]
Next, the primer layer of the hard coat film will be described.
In the hard coat film of the present invention, the arithmetic average surface roughness (Ra) of the primer layer is in the range of 0.5 nm to 15.0 nm, and the static friction coefficient of the surface of the primer layer is 0.6. It is important to be in the range of ~ 2.0.

The hard coat film of the present invention uses a primer layer between the base film and the hard coat layer, and this primer layer has an arithmetic average surface roughness (Ra) of 0.5 nm to 15.0 nm. The hard coat layer when the cycloolefin polymer film is used as a base material by having both surface characteristics that the surface static friction coefficient is in the range of 0.6 to 2.0. In particular, it is possible to greatly improve the adhesion over time.
In addition, the surface of said primer layer means the surface of the side which contacts the hard-coat layer laminated | stacked on the primer layer.

  The arithmetic average surface roughness (Ra) is the average of the absolute deviation from the average line of the roughness curve at a certain reference length, as defined in the appendix of JIS B 0031 (1994) / JIS B 0061 (1994). That is, the average value of the unevenness when the roughness curve portion below the average line is folded back to the positive value side. A specific evaluation method (measurement method) of the arithmetic average surface roughness (Ra) will be described later.

  In the present invention, in order to improve the adhesion (particularly adhesion over time) of the hard coat layer, the arithmetic average surface roughness (Ra) of the surface of the primer layer is in the range of 0.5 nm to 15.0 nm. is important. When the arithmetic average surface roughness (Ra) is less than 0.5 nm, the adhesion of the hard coat layer is deteriorated, and the processing suitability (transportability at the coater at the time of coating the hard coat layer) is deteriorated. Problems arise. Moreover, when this arithmetic mean surface roughness (Ra) is larger than 15.0 nm (exceeds 15.0 nm), the appearance may be poor after the hard coat layer is applied. In the present invention, the arithmetic average surface roughness (Ra) of the primer layer is more preferably in the range of 1.0 nm to 13.0 nm.

  The arithmetic average surface roughness (Ra) of the primer layer is determined, for example, by adding fine particles to the primer layer, the type of resin used for the primer layer, the type of solvent for the primer layer paint, and the drying conditions during primer layer coating. It is possible to adjust by changing or the like.

The static friction coefficient is a ratio between the maximum frictional force acting on the contact surface and the magnitude of the drag perpendicular to the contact surface when two objects are stationary while in contact.
In the present invention, the static friction coefficient of the surface of the primer layer is determined by using an automatic friction wear analyzer TSf-502 manufactured by Kyowa Interface Science Co., Ltd., a load of 200 gf / cm ² , a metal plate (hard chrome plating surface, surface finish). It is the value measured in 3.2 s).

In the present invention, in order to improve the adhesion (particularly the adhesion over time) of the hard coat layer, it is important that the static friction coefficient of the surface of the primer layer is in the range of 0.6 to 2.0. If this static friction coefficient is larger than 2.0 (exceeds 2.0), there may be a problem in workability (conveyance with a coater during hard coat layer coating). In addition, even if this static friction coefficient is too small, the above-described defects in workability occur, so the lower limit value of the static friction coefficient is preferably 0.6 or more. In the present invention, the coefficient of static friction of the primer layer is particularly preferably in the range of 0.6 to 1.7.

The coefficient of static friction on the surface of the primer layer is adjusted, for example, by adding fine particles to the primer layer, the type of resin used in the primer layer, the type of solvent in the primer layer paint, and the change of drying conditions during primer layer coating. Is possible.

In the hard coat film of the present invention, the arithmetic average surface roughness (Ra) and static friction coefficient of the surface of the primer layer are within the range of the present invention, thereby improving the adhesion (particularly the adhesion over time) of the hard coat layer. The reason why it can be made is estimated as follows.
The arithmetic average surface roughness (Ra) indicates a microscopic surface unevenness state in a partial section of the roughness curve, and does not necessarily indicate the entire surface unevenness state. This is a microscopic indicator. On the other hand, it is known that when the surface irregularity is large, the static friction coefficient is a point contact and a small value, and is one index that shows the surface irregularity state macroscopically.
The contact surface with the hard coat layer becomes larger due to the surface irregularities in the primer layer (increase in the surface area of the primer layer), and further, the hard coat layer enters and hardens into the surface irregularities of the primer layer. Work (throwing force) also acts, and in particular has an effect of improving adhesion over time. However, excessive surface irregularities of the primer layer cause poor appearance after coating the hard coat layer.
As described above, the arithmetic average surface roughness (Ra) and the static friction coefficient of the primer layer surface are both indicators of the surface roughness of the primer layer, and are related to the adhesion with the hard coat layer. Therefore, when the arithmetic average surface roughness (Ra) and the static friction coefficient of the primer layer surface are within the range of the present invention, the surface irregularity state of the primer layer outermost layer is in a range where the adhesion with the hard coat layer is optimum. Can be adjusted.

In the present invention, the ratio of the static friction coefficient to the dynamic friction coefficient (static friction coefficient / dynamic friction coefficient) on the surface of the primer layer is preferably 2.5 or less.
Here, the above-mentioned dynamic friction coefficient is a ratio between the friction force acting on the contact surface and the magnitude of the drag force perpendicular to the contact surface when two objects are moving while in contact with each other. In the present invention, the dynamic friction coefficient of the surface of the primer layer is determined by using an automatic friction and wear analyzer TSf-502 manufactured by Kyowa Interface Science Co., Ltd., a load of 200 gf / cm ² , a metal plate (hard chrome plating surface, surface finish). It is the value measured in 3.2 s). The static friction coefficient is as described above.

The ratio of the static friction coefficient to the dynamic friction coefficient on the surface of the primer layer (static friction coefficient / dynamic friction coefficient) indicates the index of force required to cut adhesion due to intermolecular force at the area of the true contact point (true contact area). However, in the present invention, since this ratio is 2.5 or less, the difference between the coefficient of static friction and the coefficient of dynamic friction is small, so that the hard coat layer laminated on the primer layer is particularly dynamic. Adequate adhesion can be exhibited even for good adhesion (against continuous peeling that occurs at the peeling interface). If this ratio is greater than 2.5 (exceeds 2.5), the difference between the coefficient of static friction and the coefficient of dynamic friction becomes large, resulting in poor adhesion and further workability (conveyability on the coater when applying a hard coat layer). ) May fail.
In the present invention, the ratio of the static friction coefficient to the dynamic friction coefficient (static friction coefficient / dynamic friction coefficient) on the surface of the primer layer is particularly preferably in the range of 1.0 to 2.0.

Not only the static friction coefficient of the primer layer surface but also the dynamic friction coefficient due to the addition of fine particles to the primer layer, the type of primer layer resin, the type of solvent of the primer layer paint, the change of the drying conditions at the time of primer layer coating, etc. Can also be adjusted. Thereby, it is also possible to adjust the ratio (static friction coefficient / dynamic friction coefficient) between the static friction coefficient and the dynamic friction coefficient on the surface of the primer layer.

In the present invention, the surface free energy on the surface of the primer layer is preferably 22 mN / m or more.
Here, the surface free energy is defined as “free energy of a unit area of the surface”, and is an energy that the primer layer surface has excessively compared to the inside (bulk) of the layer. The larger the surface free energy of a solid, the easier it is for gas and fine particles to be adsorbed, and the easier the liquid gets wet and to adhere to other solids.

This surface free energy can be measured by analyzing the contact angle between water and hexadecane by the Kaelble-Uy method using a contact angle meter or the like. In the present invention, the surface free energy of the primer layer is specifically determined by dropping 1 μL of water (pure water) onto the surface of the primer layer using a fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd. The contact angle after 30 seconds was measured, and further, 1 μL of n-hexadecane was dropped on the surface of the primer layer, measured after 30 seconds, and using the contact angle of water obtained and the contact angle of n-hexadecane, It is a value calculated by the Kaelble-Uy method.

The value of the surface free energy of the primer layer indicates an index of adhesion to the resin of the hard coat layer. In the present invention, when the surface free energy is 22 mN / m or more, Since the intermolecular force between the molecules and the molecules of the primer layer increases, it contributes to improving the adhesion of the hard coat layer. If the surface free energy is less than 22 mN / m, there may be a problem that the adhesion with the hard coat layer is deteriorated, or a repellency defect may occur when the hard coat layer is applied.
In the present invention, the surface free energy of the primer layer is particularly preferably 25 mN / m or more.
In addition, even if the surface free energy of the primer layer is too large, dirt is likely to adhere and foreign matter is mixed, and there is a problem that the scratch resistance is lowered. Therefore, the upper limit of the surface free energy is 40 mN / m. Or less, more preferably 38 mN / m or less, and even more preferably 35 mN / m or less.

The surface free energy of the primer layer can be adjusted by, for example, the type of resin used in the primer layer and the addition of a leveling agent to the primer layer (such as the type and amount of leveling agent).

In the present invention, the contact angle of water on the surface of the primer layer is preferably 110 degrees or less.
In the present invention, the water contact angle on the surface of the primer layer is a value measured by the method described later. That is, using a fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd., 1 μL of water (pure water) was dropped on the surface of the primer layer, and the contact angle after 30 seconds was measured.

The value of the water contact angle on the surface of the primer layer is an index indicating the adhesion to the resin used in the hard coat layer. In the present invention, the water contact angle on the surface of the primer layer is 110 degrees. By the following, the intermolecular force between the molecules of the hard coat layer resin and the molecules of the primer layer is increased, and as a result, the adhesion of the hard coat layer is improved. On the other hand, if the contact angle is larger than 110 degrees, there may be a problem that the adhesion with the hard coat layer is deteriorated, or a repellency defect may occur when the hard coat layer is applied.
In the present invention, the contact angle of water on the surface of the primer layer is particularly preferably 105 ° or less.
If the water contact angle is too low, the primer layer tends to be inferior in scratch resistance, and is desirably 50 degrees or more.

The contact angle of water on the surface of the primer layer can be adjusted, for example, by adding a leveling agent to the primer layer (type and amount of leveling agent), changing the type of resin used in the primer layer, etc. It is.

In this invention, as resin used for the said primer layer, if it is resin which forms a film, it can be especially used without a restriction | limiting.
For example, from the viewpoint of adhesion to the base film (cycloolefin polymer film), polyolefin resins, styrene acrylic resins, acrylic resins such as methyl methacrylate resins, epoxy resins, isocyanate resins, and fiber resins A series resin or a mixture of two or more of these resins can be preferably used.

The primer layer can contain inorganic or organic fine particles from the viewpoint of preventing blocking between the film surfaces. Further, by including such inorganic or organic fine particles in the primer layer, the surface properties (arithmetic average surface roughness (Ra), static friction coefficient, dynamic friction coefficient, etc.) of the primer layer can be adjusted.

  Examples of inorganic fine particles include fine particles such as alumina, zinc oxide, silica, titanium oxide, and cerium oxide. Examples of organic fine particles include fine particles such as acrylic, melamine / formaldehyde condensate, polyethylene, styrene acrylic, and polyester. It can be illustrated. As the particle size, for example, it is preferable to use fine particles of 0.05 μm to 0.20 μm.

  In addition, the primer layer can be blended with a leveling agent for the purpose of adjusting surface characteristics (surface free energy, water contact angle, etc.) and improving coatability. For example, fluorine, acrylic, siloxane , And known leveling agents such as adducts or mixtures thereof can be used. The blending amount is appropriately determined according to, for example, adjustment of surface characteristics and coating properties.

  Further, as other additives to be added to the primer layer, ultraviolet absorbers, antifoaming agents, antifouling agents, antioxidants, antistatic agents, light stabilizers, etc. are required as long as the effects of the present invention are not impaired. You may mix according to.

The coating thickness of the primer layer in the present invention is not particularly limited, but is in the range of not affecting the adhesion between the base film and the hard coat layer or the pencil hardness of the hard coat layer. A range of 1 μm to 5.0 μm is preferable. In addition, the coating film thickness of a primer layer can be measured by actually measuring with a micrometer.

  In the present invention, the primer layer is a paint (primer layer coating) in which inorganic or organic fine particles, leveling agents, other additives, and the like are dissolved and dispersed in a suitable organic solvent, if necessary, in the resin forming the primer layer. The coating material) is formed on the cycloolefin polymer film (base film) and dried. The organic solvent in this case can be appropriately selected according to the solubility of the resin contained therein, and is a solvent that can uniformly dissolve or disperse at least a solid content (resin and other additives), and at the time of coating. From the viewpoint of workability and drying properties, it is preferable to use an organic solvent having a boiling point of 50 ° C to 160 ° C, for example. Examples of such an organic solvent include aromatic solvents such as toluene, xylene, and n-heptane, aliphatic solvents such as cyclohexane, methylcyclohexane, and ethylcyclohexane, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, Known organic solvents such as ester solvents such as butyl acetate and methyl lactate, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, and alcohol solvents such as methanol, ethanol, isopropyl alcohol, n-propyl alcohol and butanol. It is also possible to use the solvents alone or in combination of several kinds as appropriate.

  In the present invention, as a method for coating the primer layer coating on the substrate film, gravure coating, microgravure coating, fountain bar coating, slide die coating, slot die coating, screen printing method It can be applied by a known coating method such as spray coating. The paint applied on the cycloolefin polymer film is usually dried at a temperature of about 50 to 120 ° C to remove the solvent while appropriately adjusting the drying conditions (temperature in the drying furnace, wind speed in the furnace, drying time, etc.). And a coating film is formed.

[Hard coat layer]
Next, the hard coat layer of the hard coat film will be described.
In the present invention, the resin contained in the hard coat layer can be used without particular limitation as long as it is a resin that forms a film, but particularly imparts the surface hardness (pencil hardness, scratch resistance) of the hard coat layer. In addition, it is preferable to use an ionizing radiation curable resin in that the degree of crosslinking can be adjusted by the exposure amount of ultraviolet rays and the surface hardness of the hard coat layer can be adjusted.

  The ionizing radiation curable resin used in the present invention is a transparent resin that is cured by irradiation with ultraviolet rays (hereinafter abbreviated as “UV”) or electron beams (hereinafter abbreviated as “EB”). Although not particularly limited, UV or EB having three or more (meth) acryloyloxy groups in one molecule in order that the coating film hardness and the hard coat layer form a three-dimensional cross-linked structure. Those composed of a curable polyfunctional acrylate are preferred. Specific examples of UV or EB curable polyfunctional acrylate having 3 or more (meth) acryloyloxy groups in the molecule include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (Meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane ethoxytriacrylate, glycerin propoxy Examples thereof include triacrylate and ditrimethylolpropane tetraacrylate. The polyfunctional acrylate may be used alone or in combination of two or more.

  Furthermore, the ionizing radiation curable resin used in the present invention is preferably a polymer having a weight average molecular weight in the range of 700 to 3600, more preferably a weight average molecular weight in the range of 700 to 3000, and a weight average molecular weight of 700. ˜2400 is more preferred. When the weight average molecular weight is less than 700, the curing shrinkage when cured by UV or EB irradiation is large, and the phenomenon that the hard coat film warps to the hard coat layer surface side (curl) increases, and the subsequent processing steps are performed. Defects occur and processing suitability is poor. On the other hand, if the weight average molecular weight exceeds 3600, the flexibility of the hard coat layer increases, but it is not suitable because the hardness is insufficient.

Further, when the ionizing radiation curable resin used in the present invention has a weight average molecular weight of less than 1500, the number of functional groups in one molecule is desirably 3 or more and less than 10. When the ionizing radiation curable resin has a weight average molecular weight of 1500 or more, the number of functional groups in one molecule is preferably 3 or more and 20 or less. If it is in the said range, curling can be suppressed and generation | occurrence | production of a crack on heat resistant conditions (100 degreeC preserve | save for 5 minutes) can be suppressed, and appropriate workability can be maintained.

Moreover, as resin contained in the said hard-coat layer, thermoplastic resins, such as polyethylene, a polypropylene, a polystyrene, a polycarbonate, polyester, an acryl, styrene-acryl, a fiber other than the above-mentioned ionizing radiation curable resin, phenol You may mix | blend thermosetting resins, such as resin, urea resin, unsaturated polyester, an epoxy, and a silicon resin, in the range which does not impair the hardness and abrasion resistance of a hard-coat layer.

It is also possible to further improve the surface hardness (scratch resistance) by incorporating inorganic oxide fine particles into the hard coat layer. In this case, the average particle size of the inorganic oxide fine particles is preferably in the range of 5 to 50 nm, more preferably in the range of 10 to 20 nm. If the average particle size is less than 5 nm, it is difficult to obtain sufficient surface hardness. On the other hand, if the average particle diameter exceeds 50 nm, the gloss and transparency of the hard coat layer are likely to be lowered, and the flexibility may be lowered.

  In the present invention, examples of the inorganic oxide fine particles include alumina and silica. Among these, alumina containing aluminum as a main component is particularly suitable because it has a high hardness and can obtain an effect with a smaller amount of addition than silica.

  In the present invention, the content of the inorganic oxide fine particles is preferably 0.1 to 10.0 parts by weight with respect to 100 parts by weight of the ionizing radiation curable resin of the hard coat layer 3. When the content of the inorganic oxide fine particles is less than 0.1 parts by weight, it is difficult to obtain an effect of improving the surface hardness (abrasion resistance). On the other hand, if the content exceeds 10.0 parts by weight, the haze increases, which is not preferable.

  The hard coat coating material for forming the hard coat layer can contain a photopolymerization initiator. As such a photopolymerization initiator, acetophenones such as commercially available IRGACURE 651 and IRGACURE 184 (both trade names: manufactured by BASF) and benzophenones such as IRGACURE 500 (trade name: manufactured by BASF) are used. it can.

  For the hard coat layer, a leveling agent can be used for the purpose of improving coatability. For example, a known leveling agent such as fluorine-based, acrylic-based, siloxane-based, or an adduct or mixture thereof can be used. It is. The blending amount can be in the range of 0.03 to 3.0 parts by weight with respect to 100 parts by weight of the solid content of the resin of the hard coat layer. In addition, in touch panel applications and the like, adhesion to the cover glass (CG), transparent conductive member (TSP), liquid crystal module (LCM), etc. of the touch panel terminal using an optical transparent adhesive OCR is required. In this case, it is preferable to use an acrylic leveling agent or a fluorine leveling agent having a high surface free energy (approximately 40 mN / m or more).

  As other additives to be added to the hard coat layer, an ultraviolet absorber, an antifoaming agent, a surface tension adjusting agent, an antifouling agent, an antioxidant, an antistatic agent, and a light stabilizer, as long as the effects of the present invention are not impaired. You may mix | blend an agent etc. as needed.

  The hard coat layer was coated with a hard coat paint in which a photopolymerization initiator, other additives and the like were dissolved and dispersed in an appropriate solvent in addition to the ionizing radiation curable resin, and dried on the primer layer. Then, by irradiating with ionizing radiation such as UV or EB, photopolymerization occurs and a hard coat layer having excellent hard properties can be obtained. The solvent can be appropriately selected depending on the solubility of the resin to be blended, and any solvent that can uniformly dissolve or disperse at least solids (resin, photopolymerization initiator, other additives, etc.) may be used. Examples of such solvents include aromatic solvents such as toluene, xylene and n-heptane, aliphatic solvents such as cyclohexane, methylcyclohexane and ethylcyclohexane, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate and acetic acid. A single known organic solvent such as an ester solvent such as butyl or methyl lactate, a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, or an alcohol solvent such as methanol, ethanol, isopropyl alcohol or n-propyl alcohol. Or it can also be used in combination of several kinds as appropriate.

  The method for coating the hard coat paint for forming the hard coat layer is not particularly limited, but gravure coating, microgravure coating, fountain bar coating, slide die coating, slot die coating, screen printing method After coating by a known coating method such as spray coating, it is usually dried at a temperature of about 50 to 120 ° C.

  The coating thickness of the hard coat layer is not particularly limited, but is preferably in the range of, for example, 1.0 μm to 5.0 μm, and more preferably in the range of 1.5 μm to 3.5 μm. . A coating thickness of less than 1.0 μm is not preferable because the required scratch resistance and pencil hardness are reduced. On the other hand, when the coating thickness exceeds 5.0 μm, curling is likely to occur strongly, and the handling property is reduced in the manufacturing process and the like, which is not preferable. The coating thickness of the hard coat layer can be measured by actually measuring with a micrometer.

[Method for producing hard coat film]
The present invention also provides a method for producing a hard coat film having the above-described configuration.
That is, the present invention is a method for producing a hard coat film having a hard coat layer containing an ionizing radiation curable resin on a cycloolefin polymer base film through a primer layer, the cycloolefin polymer base An arithmetic average surface roughness (Ra) of a primer layer obtained by applying a primer layer paint on a substrate film and drying is in a range of 0.5 nm to 15.0 nm, and the primer layer The coefficient of static friction of the surface is in the range of 0.6 to 2.0, and then a hard coat layer coating containing an ionizing radiation curable resin is applied on the primer layer and dried to form a hard coat layer. After that, it is a method for producing a hard coat film characterized by performing ionizing radiation irradiation.

The preparation of the primer layer paint and the hard coat layer paint, the coating method of these paints, the drying method of the coating film, and the like are as described above. The irradiation amount of ionizing radiation (UV, EB, etc.) after forming the hard coat layer may be an irradiation amount necessary to give the hard coat layer sufficient hardness, and the type of ionizing radiation curable resin. It can set suitably according to etc.

In addition, the ratio of the static friction coefficient to the dynamic friction coefficient (static friction coefficient / dynamic friction coefficient) of the surface of the primer layer obtained by applying the primer layer paint on the substrate film and drying is 2.5 or less. More preferably.
The surface free energy on the surface of the primer layer is more preferably 22 mN / m or more. The contact angle of water on the surface of the primer layer is more preferably 110 degrees or less.

As described in detail above, according to the present invention, a hard coat layer containing an ionizing radiation curable resin is laminated on at least one side of a cycloolefin polymer-based substrate film via a primer layer, and the primer layer When the arithmetic average surface roughness (Ra) of the primer layer is in the range of 0.5 nm to 15.0 nm and the static friction coefficient of the surface of the primer layer is in the range of 0.6 to 2.0, When the olefin polymer film is used as a base material, it is possible to obtain a hard coat film having excellent adhesion with the hard coat layer, particularly excellent with time.

Next, the embodiments of the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples.
Unless otherwise specified, “parts” and “%” described below represent “parts by weight” and “% by weight”, respectively.

[Example 1]
<Preparation of primer layer paint>
Polyolefin-based resin (modified polyolefin) “Unistor P-802 (trade name)” (solid content 22%, manufactured by Mitsui Chemicals, Inc.) with a butyl acetate / toluene = 85/15 (wt%) solid content concentration ( The primer layer paint was prepared by diluting until the paint concentration was 7.0%.

<Preparation of hard coat layer paint>
Based on 100 parts of urethane acrylate-based ultraviolet curable resin “ARTRESIN UN-908 (trade name)” (solid content 100%, (meth) acryloyloxy group number: 9, weight average molecular weight: 3600, manufactured by Negami Kogyo Co., Ltd.) Irgacure 184 (photopolymerization initiator, manufactured by BASF) 3.5 parts, TINUVIN 292 (hindered amine light stabilizer, manufactured by BASF) 2.5 parts, leveling agent MegaFac RS75 (fluorine leveling agent, DIC) Co., Ltd.) 0.3 parts diluted with butyl acetate / n-propyl alcohol = 50/50 (parts by weight) until the solid content concentration in the paint of the UV curable resin is 35% and stirred sufficiently to hard coat A layer paint was prepared.

<Preparation of primer layer coated film>
The primer layer paint described above was applied to one side of a 40 μm-thick ZEONOR film ZF14 (manufactured by Nippon Zeon Co., Ltd.) as a cycloolefin film using a bar coater (# 4). The inner air speed was 1 m / sec, and it was dried with hot air for 60 seconds to be dried and solidified to form a primer layer having a coating thickness of 0.4 μm to obtain a primer layer coated film.
The surface properties of the primer layer of the primer layer coated film thus obtained were measured for the following items. The results are shown together with other examples and comparative examples in Table 1.

(1) Arithmetic average surface roughness (Ra)
The measurement was performed using a three-dimensional surface roughness meter “VertScan2.0” manufactured by Ryoka System Co., Ltd.
[Optical conditions]
Camera: SONY HR-50 1/3 type Objective: 10 x (10 times)
Tube: 1 x Body
Relay: No Relay
Filter: 530 white
* Light intensity adjustment: Automatically performed so that the Lamp value falls within the range of 50-95.
[Measurement condition]
Mode: Phase
Size: 640 × 480
Range (μm): Start (10), Stop (−10)

(2) Static friction coefficient, dynamic friction coefficient, ratio (static friction coefficient / dynamic friction coefficient)
Using an automatic friction and wear analyzer TSf-502 manufactured by Kyowa Interface Science Co., Ltd., the static friction coefficient and the dynamic friction coefficient at a load of 200 gf / cm ² and a metal plate (hard chrome plating surface, surface finish of 3.2 s) were measured. . From the results, the ratio of the static friction coefficient to the dynamic friction coefficient (static friction coefficient / dynamic friction coefficient) was calculated.

(3) Contact angle of water Using a fully automatic contact angle meter DM-701 manufactured by Kyowa Interface Science Co., Ltd., 1 μL of water (pure water) was dropped on the surface of the primer layer, and the contact angle after 30 seconds was measured.

(4) Using a fully automatic contact angle meter DM-701 manufactured by Surface Free Energy Kyowa Interface Science Co., Ltd., 1 μL of water (pure water) is dropped on the surface of the primer layer, and the contact angle after 30 seconds is measured. Further, 1 μL of n-hexadecane is dropped on the surface of the primer layer, and measurement is performed after 30 seconds. Using the contact angle of water thus measured and the contact angle of n-hexadecane, the surface free energy was calculated by the Kaelble-Uy method.

<Preparation of hard coat film>
Next, on the primer layer of the primer layer coating film produced in exactly the same manner as described above, the hard coat layer paint is applied using a bar coater and dried with hot air in an 80 ° C. drying oven for 1 minute, A coating layer having a coating thickness of 2.5 μm was formed. This was cured using a UV irradiation apparatus set at a height of 60 mm from the coated surface at a UV irradiation amount of 180 mJ / cm ² to form a hard coat layer, and a hard coat film of this example was produced.

[Example 2]
The resin blended in the primer layer paint of Example 1 was changed to a polyolefin resin (modified polyolefin) “Unistor P-901 (trade name)” (solid content 22%, manufactured by Mitsui Chemicals, Inc.), and the solid content concentration A primer layer-coated film and a hard coat film (Example 2) were prepared in the same manner as in Example 1 except that the primer layer paint with a 7.0% was used. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 3]
The resin blended in the primer layer paint of Example 1 was changed to a polyolefin resin (modified polyolefin) “Unistor P-902 (trade name)” (solid content 22%, manufactured by Mitsui Chemicals, Inc.), and the solid content concentration A primer layer-coated film and a hard coat film (Example 3) were produced in the same manner as in Example 1 except that the primer layer paint with a 7.0% was used. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 4]
The primer was applied in the same manner as in Example 3 except that the drying conditions after application of the primer layer coating material of Example 3 were 60 ° C. in a drying oven, the wind speed in the furnace was 1 m / second, and the drying was performed with hot air for 60 seconds. A layer-coated film and a hard coat film (Example 4) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 5]
The resin blended in the primer layer paint is the same polyolefin resin (modified polyolefin) as in Example 1 “Unistor P-802 (trade name)” (solid content 22%, manufactured by Mitsui Chemicals, Inc.), and the solid content concentration is A primer layer-coated film and a hard coat film (Example 5) were produced in the same manner as in Example 1 except that the primer layer paint was 5.5% and that the primer layer had a coating thickness of 0.3 μm. . Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 6]
Example 5 is the same as Example 5 except that the primer layer coating material of Example 5 is further mixed with 0.5% of a leveling agent FT-602A (fluorine leveling agent, manufactured by Neos Co., Ltd.). Thus, a primer layer coated film and a hard coat film (Example 6) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 7]
Example 5 is the same as Example 5 except that the primer layer paint of Example 5 is further blended with 0.5% leveling agent Megafac RS-75 (fluorine leveling agent, manufactured by DIC Corporation). Thus, a primer layer coated film and a hard coat film (Example 7) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 8]
The resin blended in the primer layer paint of Example 1 was changed to a polyolefin resin (modified polyolefin) “Unistor P-901 (trade name)” (solid content 22%, manufactured by Mitsui Chemicals, Inc.), and the solid content concentration A primer layer-coated film and a hard coat film (Example 8) were prepared in the same manner as in Example 1 except that a primer layer paint with a coating amount of 5.5% was used and a primer layer with a coating thickness of 0.3 μm was used. did. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 9]
The same procedure as in Example 8 was used except that the primer layer coating material of Example 8 was further mixed with 0.5% of a leveling agent “Factent-602A” (fluorine leveling agent, manufactured by Neos Co., Ltd.). Thus, a primer layer coated film and a hard coat film (Example 9) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 10]
Example 8 is the same as Example 8 except that the primer layer coating material of Example 8 is further mixed with 0.5% leveling agent Megafac RS-75 (fluorine leveling agent, manufactured by DIC Corporation). Thus, a primer layer coated film and a hard coat film (Example 10) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 11]
The resin blended in the primer layer paint of Example 1 was changed to a polyolefin resin (modified polyolefin) “Unistor P-902 (trade name)” (solid content 22%, manufactured by Mitsui Chemicals, Inc.), and the solid content concentration A primer layer-coated film and a hard coat film (Example 11) were prepared in the same manner as in Example 1 except that a primer layer paint with 5.5% was used and a primer layer with a coating thickness of 0.3 μm was used. did. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 12]
The same procedure as in Example 11 was used, except that the primer layer paint of Example 11 was further mixed with 0.5% of a leveling agent “Factent-602A” (fluorine leveling agent, manufactured by Neos Co., Ltd.). Thus, a primer layer coated film and a hard coat film (Example 12) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 13]
Example 11 is the same as Example 11 except that the primer layer paint of Example 11 is further blended with 0.5% leveling agent Megafac RS-75 (fluorine leveling agent, manufactured by DIC Corporation). Thus, a primer layer coated film and a hard coat film (Example 13) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 14]
The resin blended in the primer layer paint of Example 1 was changed to a polyolefin resin (modified polyolefin) “Auroren S-5419T (trade name)” (solid content 15%, manufactured by Nippon Paper Industries Co., Ltd.), and the solid content concentration A primer layer was applied in the same manner as in Example 1 except that a primer layer paint having a coating amount of 3.0% was used to form a primer layer having a coating thickness of 0.2 μm. A film (Example 14) was produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 15]
A primer layer coated film in the same manner as in Example 14 except that the primer layer paint of Example 14 was applied using a bar coater (# 6) to form a primer layer having a coating thickness of 0.3 μm. And a hard coat film (Example 15) was produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 16]
A primer layer coated film in the same manner as in Example 7 except that the primer layer paint of Example 7 was applied using a bar coater (# 6) to form a primer layer having a coating thickness of 0.6 μm. And a hard coat film (Example 16) was produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Example 17]
A primer layer coated film in the same manner as in Example 7, except that the primer layer coating material of Example 7 was applied using a bar coater (# 10) to form a primer layer having a coating thickness of 1.0 μm. And a hard coat film (Example 17) was produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.
[Example 18]
In addition to the primer layer coating material of Example 5, a silica fine particle slurry “NanoTek Slurry (trade name)” (silica average particle size 30 nm, propylene glycol monomethyl ether solvent, solid content 15%, manufactured by CIK Nanotech Co., Ltd.) as solid content 30 A primer layer-coated film and a hard coat film (Example 18) were produced in the same manner as in Example 5 except that the primer layer coating material with% added was used. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Comparative Example 1]
Styrene acrylic resin “ARUFON-UG4040 (trade name)” (solid content: 100%, manufactured by Toa Gosei Co., Ltd.) with butyl acetate / toluene = 85/15 (wt%) and solid content concentration (paint concentration) of 5 A primer layer paint was prepared by diluting to 5%.
The primer layer paint described above was applied to one side of a ZEONOR film ZF14 (manufactured by Nippon Zeon Co., Ltd.) having the same thickness of 40 μm as in Example 1 using a bar coater (# 4). The air velocity in the furnace was 1 m / second, and the coating was dried and solidified by hot air drying for 60 seconds to form a primer layer having a coating film thickness of 0.3 μm to obtain a primer layer-coated film.

The surface properties of the primer layer of the primer layer coated film thus obtained were measured in the same manner as in Example 1.
Next, on the primer layer of the primer layer-coated film produced in the same manner as described above, the hard coat layer coating material of Example 1 was applied in the same manner as in Example 1 and cured by UV irradiation to hard coat layer. A hard coat film of Comparative Example 1 was produced.

[Comparative Example 2]
The primer was applied in the same manner as in Comparative Example 1 except that the drying condition after the application of the primer layer paint of Comparative Example 1 was 60 ° C. in a drying oven, the wind speed in the furnace was 1 m / sec, and the hot air was dried for 60 seconds. A layer-coated film and a hard coat film (Comparative Example 2) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Comparative Example 3]
The resin blended in the primer layer paint of Comparative Example 1 was changed to an acrylic resin “Thermolac LG-45M-30 (trade name)” (solid content 30%, manufactured by Soken Chemical Co., Ltd.), and the solid content concentration was 5 A primer layer-coated film and a hard coat film (Comparative Example 3) were prepared in the same manner as in Comparative Example 1, except that the primer layer coating was made 5%. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

[Comparative Example 4]
The primer was coated in the same manner as in Comparative Example 3 except that the drying conditions after the application of the primer layer paint of Comparative Example 3 were 60 ° C. in a drying oven, the wind speed in the furnace was 1 m / sec, and the hot air was dried for 60 seconds. A layer-coated film and a hard coat film (Comparative Example 4) were produced. Further, the surface properties of the primer layer of the primer layer coated film were measured in the same manner as in Example 1.

The hard coat films of Examples and Comparative Examples produced as described above were evaluated for the following items, and the results are summarized in Table 1.

(1) Thickness of coating film The formation thickness of the coating film of a primer layer and a hard-coat layer was measured using Thin-Film Analyzer F20 (brand name) (made by FILMETRICS).

(2) Adhesion (initial adhesion and adhesion over time (wet heat adhesion))
Initial adhesion was evaluated according to JIS-K5600-5-6. Specifically, for each hard coat film, under normal conditions, that is, constant temperature and humidity conditions (23 ° C., 50% RH), 100 cross cuts of 1 mm ² were prepared using a cross-cut peel test jig, Adhesive tape No. 252 manufactured by Sekisui Chemical Co., Ltd. was affixed thereon, pressed uniformly with a spatula, peeled in the direction of 60 degrees, and the remaining number of hard coat layers was evaluated in four stages. The evaluation criteria are as follows, and ◎ and ○ evaluation products (that is, the hard coat layer remaining rate of 90% or more) were judged to be acceptable.
: 100
○: 99-90
Δ: 89-50
×: 49 to 0

In addition, wet heat adhesion (adhesion over time under wet heat conditions) was determined by storing each hard coat film under wet heat conditions (80 ° C., 90% RH) for 30 days, and then performing a cross-cut peel test in the same manner as described above. The adhesion of the hard coat layer was evaluated in four stages. The evaluation criteria are the same as in the case of the above initial adhesion.

(3) Pencil hardness About each hard coat film, pencil hardness was measured by the test method according to JIS-K-5600-5-4. The hardness was measured without causing scratches on the surface. About the criteria, hardness 3B or more was set as the pass.

(4) Scratch resistance For each hard coat film, the hard coat layer surface was subjected to 10 reciprocating frictions using steel wool # 0000, applying a load of 1 kg, by a test method according to JIS-K-5600-5-10. The degree of scratching was evaluated according to the following criteria. ○ The evaluation product was considered to have good scratch resistance. ΔEvaluated products can also be used as products.
○: No scratch
Δ: Some scratches occur
×: Innumerable scratches

As is apparent from the results of Table 1 above, according to the examples of the present invention, a cyclocoat polymer film was used as a base material, and a hard coat film excellent in adhesiveness with a hardcoat layer, particularly adhesive with time, was obtained. Can be obtained. Moreover, according to the Example of this invention, the hard coat film excellent also in the hard property (pencil hardness, abrasion resistance) of a hard-coat layer can be obtained.

On the other hand, in the hard coat film of the comparative example in which the static friction coefficient of the surface of the primer layer does not satisfy the range of the present invention, both the initial adhesion and the adhesion over time are particularly inferior, and the adhesion failure of the hard coat layer occurs. Cheap. In the hard coat film of the comparative example, the above pencil hardness test could not be properly evaluated due to poor adhesion of the hard coat layer.

Claims (7)

A hard coat film in which a hard coat layer containing an ionizing radiation curable resin is laminated on at least one side of a cycloolefin polymer-based substrate film via a primer layer,
The arithmetic average surface roughness (Ra) of the primer layer is in the range of 0.5 nm to 15.0 nm, and the static friction coefficient of the surface of the primer layer is in the range of 0.6 to 2.0. Hard coat film.   2. The hard coat film according to claim 1, wherein a ratio of a static friction coefficient to a dynamic friction coefficient on the surface of the primer layer (static friction coefficient / dynamic friction coefficient) is 2.5 or less.   The hard coat film according to claim 1, wherein a surface free energy of the primer layer is 22 mN / m or more.   The hard coat film according to any one of claims 1 to 3, wherein a contact angle of water on the surface of the primer layer is 110 degrees or less.   The hard coat layer contains a polyfunctional acrylate having three or more (meth) acryloyloxy groups in one molecule as the ionizing radiation curable resin. The hard coat film as described. A method for producing a hard coat film having a hard coat layer containing an ionizing radiation curable resin on a cycloolefin polymer-based substrate film via a primer layer,
The arithmetic average surface roughness (Ra) of the primer layer obtained by applying and drying the primer layer coating on the cycloolefin polymer base film is in the range of 0.5 nm to 15.0 nm, The static friction coefficient of the surface of the primer layer is in the range of 0.6 to 2.0,
Next, a hard coat film is produced by applying a coating for a hard coat layer containing an ionizing radiation curable resin on the primer layer and drying to form a hard coat layer, followed by irradiation with ionizing radiation. Method. The method for producing a hard coat film according to claim 6, wherein a ratio of a static friction coefficient to a dynamic friction coefficient on the surface of the primer layer (static friction coefficient / dynamic friction coefficient) is 2.5 or less.