JP2016084478A - Liquid curable resin composition, manufacturing method of image display unit using the same and device for displaying images - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a material excellent in moisture heat resistance reliability while capable of suitably being applied for filling space between a protection panel and an image display unit of a device for displaying large images.SOLUTION: There is provided a liquid curable resin composition containing (A) an acrylic polymer, (B) a polymer having an ethylenically unsaturated bond in a molecule, (C) a monomer having an ethylenically unsaturated group in a molecule and (D) a polymerization initiator with the content of the (C) component of 5 to 25 mass% based on the total amount of the (A) component, the (B) component and the (C) component.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid curable resin composition, a method for producing an image display device using the same, and an image display device.

  A liquid crystal display device is illustrated as a typical image display device. A liquid crystal display device includes a liquid crystal cell in which liquid crystal is filled and sealed through a gap of about several microns between a glass substrate having a thickness of about 1 mm on which transparent electrodes and pixel patterns are formed, and both outer surfaces of the liquid crystal cell. The liquid crystal panel which consists of light sources, such as a polarizing plate affixed on and a backlight system, is included.

  The polarizing plate that makes up this liquid crystal panel is thin and easily scratched. Especially in mobile phones, game consoles, digital cameras, and in-vehicle applications, a transparent front plate (protective panel) with a certain space in front of the liquid crystal panel In general, a liquid crystal display device having a structure provided with a) is used.

  Furthermore, in recent years, touch panels have been mounted on mobile phones, game machines, digital cameras, in-vehicle parts, notebook computers, desktop computers, personal computer monitors, and the like. In the case of such a liquid crystal display device, a protective panel, a touch panel, and a liquid crystal panel are stacked in this order, and a constant structure is provided between the protective panel and the touch panel, and between the touch panel and the liquid crystal panel. There exists a space.

  When the space in the above-mentioned liquid crystal display device is air, this space causes light scattering, resulting in a decrease in contrast, brightness, and transmittance, and a decrease in image quality due to double projection. obtain.

  Therefore, in Cited Document 1, a method of filling an oily material in the space between the protective panel and the liquid crystal panel is disclosed, and in Cited Document 2, a sheet obtained by copolymerizing an acrylic monomer is interposed between the protective panel and the liquid crystal panel. Each method has been proposed.

  In addition, a plasma display panel (PDP) which is one of flat panel displays (FPD) is provided with a space of about 1 to 5 mm from the PDP and a protective panel made of glass or the like having a thickness of about 3 mm in order to prevent cracking of the PDP. Is provided on the front surface (viewing surface side).

  Therefore, in order to prevent the above-described light scattering and display cracking, in Patent Documents 3 and 4, between the protection panel and an image display unit such as a plasma display panel and a liquid crystal panel, the protection panel and the touch panel And a method of interposing an optical film made of a specific resin in a space between the touch panel and the image display unit (hereinafter also referred to as “a space between the protective panel and the image display unit”). Yes.

JP 05-011239 A JP 2004-125868 A JP 2004-058376 A JP 2009-024160 A

  However, the oil used in Patent Document 1 is difficult to seal to prevent leakage, and there is a possibility that the material used in the liquid crystal panel may be eroded, so that the oil leaks when the protective panel is cracked. There's a problem.

  In addition, the optical film made of the resin described in Patent Document 3 has a problem that it becomes cloudy when a short-time wet heat resistance test is performed after application to a display.

  Further, the optical films (sheets) of Patent Documents 2 and 4 have room for improvement when applied to an image display device such as a liquid crystal display device having a larger size. That is, it is difficult to uniformly produce a large area optical film corresponding to a large image display device, and even if such an optical film can be produced, the large area optical film can be uniformly displayed as a large image. It is difficult to stack on the equipment. If the optical film cannot be laminated uniformly, it may cause problems such as color unevenness.

  Therefore, the present invention can be suitably applied to fill a space between a protective panel and an image display unit in a large-sized image display device, and has excellent moisture heat resistance, and an image using the material. It is an object of the present invention to provide a method for manufacturing a display device and an image display device.

  In view of the above circumstances, the present invention provides (A) an acrylic polymer (hereinafter, sometimes referred to as “component (A)”), (B) a polymer having an ethylenically unsaturated bond in the molecule (hereinafter, occasionally). (Referred to as “component (B)”), (C) a monomer having one ethylenically unsaturated group in the molecule (hereinafter sometimes referred to as “component (C)”), and (D) a polymerization initiator. (Hereinafter referred to as “component (D)” in some cases), and the content of component (C) is 5 to 25 with respect to the total amount of component (A), component (B) and component (C). A liquid curable resin composition (hereinafter, also simply referred to as “curable resin composition”) having a mass% is provided.

  Such a curable resin composition is excellent in transparency when cured, has a small curing shrinkage rate, and is further excellent in wet heat resistance. Since the curable resin composition of the present invention is excellent in transparency when cured, it can be suitably used as a material used in the production of an image display device. Further, since the curable resin composition of the present invention exists in a liquid state, the space between the protective panel and the image display unit can be uniformly filled. Furthermore, since the curable resin composition of the present invention has a low curing shrinkage rate, it is possible to suppress warping of the substrate that may occur when cured with light or heat. Therefore, the curable resin composition of the present invention can be suitably used for filling the space between the protective panel and the image display unit in the large image display device.

  According to the knowledge of the present inventors, performance required for a film and a liquid curable resin composition as a material used for filling a space between the protective panel and the image display unit, etc. However, it is difficult to apply the material in the film to the liquid curable resin composition as it is.

  The component (B) is preferably a urethane polymer having a (meth) acryloyl group from the viewpoints of adhesiveness and toughness.

  From the viewpoint of workability and suppression of voids (bubbles in the curable resin composition), the curable resin composition described above contains substantially no organic solvent and has a viscosity at 25 ° C. of 500 to 5000 mPa · s. Preferably there is. Note that “substantially free of organic solvent” means that the organic solvent may be present in a trace amount as long as the characteristics of the present invention are not significantly reduced. Specifically, the content of the organic solvent may be 1000 ppm or less, preferably 500 ppm or less, and more preferably 100 ppm or less, based on the total amount of the curable resin composition. Further, it is particularly preferable that no organic solvent is contained. Here, the organic solvent is an organic compound that does not have an ethylenically unsaturated group in the molecule, is liquid at 25 ° C., and has a boiling point of 250 ° C. or less at atmospheric pressure.

  The present invention is a method for manufacturing an image display device comprising an image display unit and a protection panel, the step of interposing the curable resin composition between the image display unit and the protection panel, and the protection And a process for curing the curable resin composition by irradiating light from the panel surface side. The present invention is also a method for manufacturing an image display device including an image display unit, a touch panel, and a protection panel, and between the image display unit and the touch panel and / or between the touch panel and the protection panel. Provided is a method for producing an image display device, comprising the step of interposing the curable resin composition and the step of curing the liquid curable resin composition by irradiating light from the protective panel surface side.

  The present invention further provides an image display device manufactured by the above-described manufacturing method.

  According to the present invention, in the manufacturing process of an image display device that is cured after filling the space between the protective panel and the image display unit with the resin composition, it is transparent, excellent in heat and humidity resistance, and cure shrinkage. It is possible to provide a curable resin composition having a low rate and a small stress applied to the image display unit.

  Furthermore, according to the present invention, it is possible to provide an image display device that has impact resistance, can produce a clear and high-contrast image without double reflection.

It is side surface sectional drawing which shows typically one Embodiment of the liquid crystal display device which is an example of the image display apparatus of this invention. It is side surface sectional drawing which shows typically the liquid crystal display device which mounts the touchscreen which is one Embodiment of the liquid crystal display device which is an example of the image display apparatus of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the embodiments. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  In this specification, “(meth) acrylate” means “acrylate” and “methacrylate” corresponding thereto. Similarly, “(meth) acryl” means “acryl” and “methacryl” corresponding thereto, and “(meth) acryloyl” means “acryloyl” and corresponding “methacryloyl”.

  The curable resin composition of the present invention has (A) an acrylic polymer, (B) a polymer having an ethylenically unsaturated bond in the molecule, and (C) one ethylenically unsaturated group in the molecule. It contains a monomer and (D) a polymerization initiator. Hereinafter, each component will be described.

<(A) component: Acrylic polymer>
The acrylic polymer as component (A) can be produced, for example, by radical polymerization of a polymerizable compound having a (meth) acryl group (hereinafter sometimes referred to as “monomer”). The acrylic polymer includes a polymerizable compound having a (meth) acryl group, styrene; a polymerizable styrene derivative substituted at the α-position or aromatic ring such as vinyltoluene and α-methylstyrene, It may be copolymerized with one or more polymerizable monomers such as vinyl alkyl ether and esters of vinyl alcohol.

  Examples of the polymerizable compound having the (meth) acryl group include alkyl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylamide, (meth) acrylonitrile, tetrahydrofurfuryl (meth) acrylate, dimethylaminoethyl ( (Meth) acrylate, diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, Examples thereof include a (meth) acryl group and a compound having a hydroxyl group or an ether bond. These can be used individually by 1 type or in combination of 2 or more types.

  As said alkyl (meth) acrylate, the (C1) component mentioned later can be mentioned, for example. Examples of the compound having a (meth) acryl group and a hydroxyl group or an ether bond in the molecule include the component (C2) described later.

  The acrylic polymer is a (meth) acrylate having a structural unit derived from an alkyl (meth) acrylate having 4 to 18 carbon atoms and a hydroxyl group or an ether bond from the viewpoint of heat and humidity resistance and transparency (high haze). It is preferable to include a structural unit derived from an alkyl (meth) acrylate having 6 to 12 carbon atoms and a structural unit derived from a hydroxyalkyl (meth) acrylate having 1 to 5 carbon atoms. preferable.

  In the case where the component (A) includes a structural unit derived from an alkyl (meth) acrylate having 4 to 18 carbon atoms, alkyl (meth) having 4 to 18 carbon atoms from the viewpoint of heat and humidity resistance and transparency (high haze). The content of the structural unit derived from the acrylate is preferably 50 to 90% by mass, more preferably 55 to 85% by mass, based on the total mass (solid content) of the component (A). More preferably, it is 60-80 mass%, and it is especially preferable that it is 65-75 mass%.

  In addition, when the component (A) contains a structural unit derived from a (meth) acrylate having a hydroxyl group or an ether bond, it has a hydroxyl group or an ether bond from the viewpoint of wet heat resistance and transparency (high haze). The content of the structural unit derived from the acrylate is preferably 10 to 45% by mass, more preferably 15 to 40% by mass, based on the total mass (solid content) of the component (A), and more preferably 20 to 35%. It is more preferable that it is mass%, and it is especially preferable that it is 25-30 mass%.

  The weight average molecular weight of the component (A) is preferably from 4,000 to 40,000, more preferably from 5,000 to 30,000, from the viewpoints of curability, moist heat resistance and workability. 7,000 to 20,000 is particularly preferable.

In the present specification, the weight average molecular weight is a value measured by gel permeation chromatography (GPC) and converted using a standard polystyrene calibration curve. Further, the number average molecular weight, the weight average molecular weight, and the degree of dispersion are defined as follows.
(A) Number average molecular weight (Mn)
Mn = Σ (NiMi) / ΣNi = ΣXiMi
(Xi = Mole fraction of molecules with molecular weight Mi = Ni / ΣNi)
(B) Weight average molecular weight (Mw)
Mw = Σ (NiMi ² ) / ΣNiMi = ΣWiMi
(Wi = Molecular weight molecular weight fraction = NiMi / ΣNiMi)
(C) Molecular weight distribution (dispersion degree)
Dispersity = Mw / Mn

  The content of the component (A) in the curable resin composition is 15 to 15 with respect to the total amount of the component (A), the component (B), and the component (C) from the viewpoints of curability, adhesion, and cure shrinkage. 60 mass% is preferable, it is more preferable that it is 20-50 mass%, and it is especially preferable that it is 25-45 mass%.

  The (A) acrylic polymer is produced by a conventionally known method using the above-described components, for example, a method in which the above-described components are reacted in the presence of a radical polymerization initiator such as an organic peroxide or an azo compound. can do.

<(B) component: a polymer having an ethylenically unsaturated bond in the molecule>
Examples of the polymer having an ethylenically unsaturated bond in the molecule as component (B) include a polyester oligomer having a (meth) acryloyl group, a urethane polymer having a (meth) acryloyl group, and polyethylene glycol mono (meth). Examples include acrylate, polyethylene glycol di (meth) acrylate, polyprolene glycol mono (meth) acrylate, and polyprolene glycol di (meth) acrylate.

  Among these, a urethane polymer having a (meth) acryloyl group is preferable from the viewpoint of the toughness of the cured product and the balance of various properties.

  The urethane polymer having the (meth) acryloyl group is, for example, a compound obtained by reacting (b1) a diol compound and (b2) a compound having an isocyanate group (hereinafter referred to as “urethane polymer”). And (b3) monohydroxy (meth) acrylate, (b4) monocarboxylic acid having (meth) acryloyl group, or monoisocyanate compound having (meth) acryloyl group. it can.

  (B1) Examples of the diol compound include polyether diols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; polyolefin diols such as polybutadiene diol, polyisoprene diol, hydrogenated polybutadiene diol, and hydrogenated polyisoprene diol; polyester diol , Polycaprolactone diol, and silicone diol. Among these, polyether diol is preferable from the viewpoint of relaxation of stress / impact, transparency, adhesiveness, and compatibility with the component (A).

（式（２）中、Ｘは２価の有機基を示す。） As said (b2) compound which has an isocyanate group, the diisocyanate compound represented by following General formula (2) is mentioned, for example.

(In formula (2), X represents a divalent organic group.)

  Examples of the divalent organic group represented by X in the general formula (2) include an aliphatic group having 1 to 20 carbon atoms, an alicyclic group having 5 to 20 carbon atoms, an unsubstituted group, and a methyl group. And arylene groups such as a phenylene group and a naphthylene group substituted with a lower alkyl group having 1 to 5 carbon atoms. The aliphatic group having 1 to 20 carbon atoms is more preferably an aliphatic hydrocarbon group having 1 to 20 carbon atoms.

  Examples of the diisocyanates represented by the general formula (2) include diphenylmethane-2,4′-diisocyanate; 3,2′-, 3,3′-, 4,2′-, 4,3′-, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate; 3,2'-, 3,3'-, 4,2'- 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-diethyldiphenylmethane-2,4'-diisocyanate; 3,2'-, 3,3 ' -, 4,2'-, 4,3'-, 5,2'-, 5,3'-, 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate; diphenylmethane-4 , 4'-diisocyanate; diphenylmethane-3,3'-diisocyanate; diphenylmeta Diphenylmethane diisocyanate compounds such as -3,4'-diisocyanate and hydrogenated products thereof; diphenyl ether-4,4'-diisocyanate; benzophenone-4,4'-diisocyanate; diphenylsulfone-4,4'-diisocyanate; tolylene-2 , 4-diisocyanate; tolylene-2,6-diisocyanate; m-xylylene diisocyanate; p-xylylene diisocyanate; 1,5-naphthalene diisocyanate; 4,4 ′-[2,2bis (4-phenoxyphenyl) propane] Diisocyanate; aromatic diisocyanate such as tolylene diisocyanate; hexamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate DOO; isophorone diisocyanate; 4,4'-dicyclohexylmethane diisocyanate; trans-cyclohexane-1,4-diisocyanate; hydrogenated m- xylylene diisocyanate, aliphatic or alicyclic diisocyanates such as lysine diisocyanate. Among these diisocyanates, from the viewpoint of further improving the transparency, X in the general formula (2) is a group having an aliphatic group having 1 to 20 carbon atoms or an alicyclic group having 5 to 20 carbon atoms. It is preferred to use certain aliphatic or alicyclic diisocyanate compounds. These can be used alone or in combination of two or more. In addition, as a compound which has an isocyanate group, you may use trifunctional or more polyisocyanate with the diisocyanate represented by General formula (2).

  The diisocyanates represented by the general formula (2) may be those stabilized with a blocking agent necessary for avoiding changes over time. Examples of the blocking agent include hydroxy acrylate, alcohols typified by butanol, phenol, oxime, and the like, but are not particularly limited.

  The blending ratio when the (b1) diol compound and the diisocyanate represented by the general formula (2) are reacted is the number average molecular weight of the urethane polymer to be produced, and the terminal of the urethane polymer to be produced is a hydroxyl group. It is appropriately adjusted depending on whether it is an isocyanate group.

  When the end of the urethane polymer is an isocyanate group, the ratio of the number of isocyanate groups to the number of hydroxyl groups (isocyanate group / hydroxyl group number) is preferably adjusted to be 1.01 or more, and the viewpoint of increasing the number average molecular weight Is preferably adjusted to less than 2. By setting such a ratio, a urethane polymer whose terminal is an isocyanate group can be obtained.

  When the end of the urethane polymer is an isocyanate group, (b3) a compound capable of reacting with an isocyanate group such as a monohydroxy (meth) acrylate compound is used as a compound for introducing the (meth) acryloyl skeleton. Can do.

  (B3) Examples of the monohydroxy (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 1,4-cyclohexanedimethanol mono (Meth) acrylate, caprolactone or alkylene oxide adduct of each of the above (meth) acrylates, glycerin di (meth) acrylate, trimethylol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate , Ditrimethylolpropane tri (meth) acrylate, and 2-acryloxyethanol. These compounds can be used individually by 1 type or in combination of 2 or more types.

  On the other hand, when the terminal of the urethane polymer is a hydroxyl group, the blending ratio is preferably adjusted so that the ratio of the number of hydroxyl groups to the number of isocyanate groups (number of hydroxyl groups / isocyanate groups) is 1.01 or more. It is preferable to adjust to less than 2 from the viewpoint of increasing.

  When the terminal of the urethane polymer is a hydroxyl group, (b4) a monocarboxylic acid having a (meth) acryloyl group or a monoisocyanate having a (meth) acryloyl group as a compound for introducing a (meth) acryloyl skeleton A compound capable of reacting with a hydroxyl group such as a compound can be used.

Examples of the monocarboxylic acid having a (meth) acryloyl group include (meth) acrylic acid, and examples of the monoisocyanate compound having a (meth) acryloyl group include 2-isocyanatoethyl (meth) acrylate. .
Moreover, the urethane polymer which has a (meth) acryloyl group can also be manufactured by methods other than the above.
As other methods for producing a urethane polymer having a (meth) acryloyl group, for example, (b1) a diol compound and (b3) monohydroxy (meth) acrylate are mixed in a predetermined amount, and the temperature is raised to a predetermined temperature. After that, (b2) a predetermined amount of the compound having an isocyanate group is added to the mixture of the component (b1) and the component (b3) over a predetermined time and allowed to react.
In addition, (B) the polymer having an ethylenically unsaturated bond in the molecule is a conventionally known method using the above components, for example, the presence of a polymerization inhibitor such as p-methoxyphenol and a catalyst such as dibutyltin dilaurate. It can manufacture by the method of making the above-mentioned component react under.

The average number of functional groups in the component (B) is preferably 0.5 to 2 and more preferably 0.5 to 1.5 from the viewpoint of further reducing the viscosity and curing shrinkage of the curable resin composition. More preferably, it is particularly preferably 0.5 to 1. The “functional group number” indicates the number of functional groups ((meth) acryloyl group) in one molecule of the component (B), and the “average functional group number” indicates the number of functional groups per molecule in the entire component (B). The average value is shown. The average number of functional groups can be calculated from the number of moles of each component when the component (B) is synthesized. In addition, the average number of functional groups can be calculated from the integrated value of ¹ H-NMR of the component (B).

  The weight average molecular weight of the component (B) is preferably 1,000 to 40,000, more preferably 3,000 to 30,000, from the viewpoints of curability, moist heat resistance and workability. 5,000 to 20,000 is particularly preferable, and 6,000 to 10,000 is more preferable.

  The content of the component (B) in the curable resin composition is from 30 to the total amount of the component (A), the component (B), and the component (C) from the viewpoints of curability, adhesion, and cure shrinkage. 80 mass% is preferable, it is more preferable that it is 40-70 mass%, and it is especially preferable that it is 45-65 mass%.

式（３）中、Ｒ^１は水素原子又はメチル基を示し、Ｒ^２は炭素数４〜２０のアルキル基を示す。接着性、及び柔軟性をより付与させる観点から、Ｒ^２は炭素数６〜１８のアルキル基が好ましく、８〜１６のアルキル基がより好ましい。 <(C) component: a monomer having one ethylenically unsaturated group in the molecule>
The monomer having one ethylenically unsaturated group in the molecule as component (C) is preferably liquid at room temperature (25 ° C.), particularly from the viewpoint of imparting adhesiveness and flexibility. It is preferable that an alkyl (meth) acrylate (hereinafter, also referred to as “(C1) component”) represented by the following general formula (3) is mainly included. In addition, from the viewpoint of wet heat resistance and workability during coating, a compound having a (meth) acryl group and a hydroxyl group or an ether bond in the molecule (hereinafter also referred to as “(C2) component”) is included. Is more preferable.

In Formula (3), R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group having 4 to 20 carbon atoms. From the viewpoint of imparting more adhesiveness and flexibility, R ² is preferably an alkyl group having 6 to 18 carbon atoms, more preferably an alkyl group having 8 to 16 carbon atoms.

<(C1) component>
Examples of the alkyl (meth) acrylate represented by the general formula (3) include n-butyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, and n-pentyl (meth) acrylate. , N-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, n-hexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (Meth) acrylate etc. are mentioned. These can be used alone or in combination of two or more.
The content ratio of the component (C1) in the component (C) is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

<(C2) component>
Examples of the compound having a (meth) acryl group and a hydroxyl group or an ether bond in the molecule include 2-hydroxyethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3 -Hydroxypropyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1-hydroxybutyl (meta ) Hydroxyl-containing (meth) acrylates such as acrylate; Hydroxyl-containing (meth) acrylamides such as hydroxyethyl (meth) acrylamide; Polyethylene glycol mono (meth) such as diethylene glycol and triethylene glycol Crylate; Polypropylene glycol mono (meth) acrylates such as dipropylene glycol and tripropylene glycol; Polybutylene glycol mono (meth) acrylates such as dibutylene glycol and tributylene glycol; Morpholine group-containing (meth) acrylates such as acryloylmorpholine It is done. Among these, 4-hydroxybutyl acrylate and acryloyl morpholine are preferable from the viewpoint of improving the heat and heat resistance reliability and the workability during coating. These acrylates may be used in combination of two or more.

  As the component (C), a monomer having one ethylenically unsaturated group in the molecule other than the components (C1) and (C2) can also be used. Examples of the monomer having one ethylenically unsaturated group in the molecule other than the component (C1) and the component (C2) include isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, di Examples include (meth) acrylates having a cycloaliphatic structure such as cyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, benzyl (meth) acrylate, phenoxy (meth) acrylate, and styrene.

  Although content of (C) component in curable resin composition is 5-25 mass% with respect to the total amount of (A) component, (B) component, and (C) component, it is 8-25 mass%. Preferably, 10 to 25% by mass is more preferable, and 10 to 20% by mass is particularly preferable. When the content of the component (C) is 5% by mass or more, workability is improved because the viscosity of the curable resin composition does not increase excessively. Further, when the content of the component (C) is within 25% by mass, the curing shrinkage rate is lowered, and the reliability when used in an image display device can be improved.

  As the component (C), the content ratio of the component (C1) when the component (C1) and the component (C2) are used in combination is from the viewpoint of reducing the transparency of the cured product (high haze) and deformation of the cured product. (C) 50-95 mass% is preferable in the total amount of a component, it is more preferable that it is 60-90 mass%, and it is especially preferable that it is 70-85 mass%. Further, the content ratio of the component (C2) is preferably 5 to 50% by mass in the total amount of the component (C) from the viewpoint of reducing the transparency (high haze) of the cured product and the deformation of the cured product. More preferably, it is 40 mass%, and it is especially preferable that it is 15-30 mass%.

<(D) component: Polymerization initiator>
As (D) polymerization initiator, either (D1) photopolymerization initiator or (D2) thermal polymerization initiator can be used, and these may be used in combination.

  (D1) As a photoinitiator, well-known materials, such as a benzophenone series, anthraquinone series, a benzoin series, a sulfonium salt, a diazonium salt, an onium salt, can be used, for example. These are particularly sensitive to ultraviolet light.

  (D1) Specific examples of the photopolymerization initiator include benzophenone, N, N′-tetramethyl-4,4′-diaminobenzophenone (Michler ketone), N, N-tetraethyl-4,4′-diaminobenzophenone, 4- Methoxy-4′-dimethylaminobenzophenone, α-hydroxyisobutylphenone, 2-ethylanthraquinone, t-butylanthraquinone, 1,4-dimethylanthraquinone, 1-chloroanthraquinone, 2,3-dichloroanthraquinone, 3-chloro-2- Methyl anthraquinone, 1,2-benzoanthraquinone, 2-phenylanthraquinone, 1,4-naphthoquinone, 9,10-phenanthraquinone, thioxanthone, 2-chlorothioxanthone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy- , 2-diphenylethane-1-one, aromatic ketone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin compounds such as benzoin, methylbenzoin, and ethylbenzoin, benzoin methyl ether, benzoin Benzoin ether compounds such as ethyl ether, benzoin isobutyl ether, benzoin phenyl ether, benzyl, 2,2-diethoxyacetophenone, benzyldimethyl ketal, ester compound of β- (acridin-9-yl) acrylic acid, 9-phenylacridine, Acridine compounds such as 9-pyridylacridine, 1,7-diacridinoheptane, 2- (o-chlorophenyl) -4,5-diphenylimidazole dimer, 2- (o-chlorophenyl) -4,5-di ( m-methoxyph Nyl) imidazole dimer, 2- (o-fluorophenyl) -4,5-diphenylimidazole dimer, 2- (o-methoxyphenyl) -4,5-diphenylimidazole dimer, 2- (p- Methoxyphenyl) -4,5-diphenylimidazole dimer, 2,4-di (p-methoxyphenyl) 5-phenylimidazole dimer, 2- (2,4-dimethoxyphenyl) -4,5-diphenylimidazole Dimer, 2,4,5-triarylimidazole dimer such as 2- (p-methylmercaptophenyl) -4,5-diphenylimidazole dimer, 2-benzyl-2-dimethylamino-1- ( 4-Morpholinophenyl) -1-butanone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-1-propane, bis (2,4,4) - trimethyl benzoyl) - phenyl phosphine oxide, oligo (2-hydroxy-2-methyl-1- (4- (1-methylvinyl) phenyl) propanone) and the like.

  In particular, photopolymerization initiators that improve transparency without coloring the curable resin composition include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one. , Α-hydroxyalkylphenone compounds such as 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, bis (2,4,6-trimethyl) Acylphosphine oxides such as benzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide Compounds, oligo (2-hydroxy-2-methyl-1- (4- (1-methyl ) Phenyl) propanone) and a combination thereof are preferred.

  Moreover, as a photoinitiator for producing a thick film, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl Acylphosphine oxide compounds such as -pentylphosphine oxide and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide are preferred.

  A plurality of these photopolymerization initiators may be used in combination.

  (D2) The thermal polymerization initiator is an initiator that generates radicals by heat. Specific examples thereof include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, t-hexyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, lauroyl peroxide, diacetylper Organic peroxides such as oxides; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonyl), 2,2'-azobis (2,4-dimethylvaleronitrile 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate), 4,4′-azobis (4-cyanovaleric acid) ), 2,2′-azobis (2-hydroxymethylpropionitrile), 2,2′-azobis [2- (2-imidazolin-2-yl) propane].

  The content of the (D) polymerization initiator in the curable resin composition is preferably 0.01 to 5% by mass with respect to the total amount of the component (A), the component (B) and the component (C), and 0.02 -3 mass% is more preferable, and 0.03-2 mass% is especially preferable.

  (D) When (D1) photopolymerization initiator is used as the polymerization initiator, the content thereof is 0.1-5 with respect to the total amount of component (A), component (B) and component (C). % By weight is preferable, and when (D2) a thermal polymerization initiator is used, the content thereof is 0.01 to 1% by weight with respect to the total amount of the component (A), the component (B) and the component (C). Is preferred. In addition, when using together (D1) photoinitiator and (D2) thermal polymerization initiator, it is preferable to use in these ranges, respectively.

  The curing reaction can be performed by a curing reaction by irradiation with active energy rays, a curing reaction by heat, or a combination thereof. Active energy rays refer to ultraviolet rays, electron beams, α rays, β rays, γ rays and the like. These methods can also be used for the synthesis of (A) an acrylic polymer.

  In addition, when apply | coating or casting and hardening | curing a curable resin composition, it may be difficult for the reason that the high temperature tolerance of the polarizing plate used for the liquid crystal panel is low. In this case, it is preferable to use a photopolymerization initiator (D1) that can be polymerized by light.

  It is preferable that the curable resin composition of this embodiment does not contain an organic solvent substantially. The viscosity (25 ° C.) of the curable resin composition of the present embodiment containing substantially no organic solvent is preferably 500 to 5000 mPa · s, more preferably 1000 to 4000 mPa · s. The viscosity is a value measured from an E-type viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) using a 3 ° cone rotor at 0.5 rpm.

  The curing shrinkage when the curable resin composition of the present embodiment is cured is preferably less than 3.0% from the viewpoint of further suppressing the warpage of the substrate such as the protective panel and the image display unit. More preferably, it is less than 1.5%. When the image display unit is warped, it may cause problems such as color unevenness.

<Image display device>
Hereinafter, a liquid crystal display device which is an example of an image display device that can be manufactured by using the curable resin composition of the present embodiment will be described.

  FIG. 1 is a side sectional view schematically showing an embodiment of the liquid crystal display device of the present invention. The liquid crystal display device shown in FIG. 1 includes an image display unit 1 in which a backlight system 50, a polarizing plate 22, a liquid crystal display cell 10, and a polarizing plate 20 are laminated in this order, and a polarizing plate on the viewing side of the liquid crystal display device. The transparent resin layer 32 provided on the upper surface of 20 and the transparent protective substrate (protective panel) 40 provided on the surface thereof. The transparent resin layer 32 is composed of a cured body of the curable resin composition of the present embodiment.

  FIG. 2 is a side cross-sectional view schematically showing a liquid crystal display device equipped with a touch panel, which is an embodiment of the liquid crystal display device of the present invention. The liquid crystal display device shown in FIG. 2 includes an image display unit 1 in which a backlight system 50, a polarizing plate 22, a liquid crystal display cell 10, and a polarizing plate 20 are laminated in this order, and a polarizing plate on the viewing side of the liquid crystal display device. 20, a transparent resin layer 32 provided on the top surface, a touch panel 30 provided on the top surface of the transparent resin layer 32, a transparent resin layer 31 provided on the top surface of the touch panel 30, and a transparent protective substrate provided on the surface thereof 40.

  In the liquid crystal display device of FIG. 2, a transparent resin layer is interposed between the image display unit 1 and the touch panel 30 and between the touch panel 30 and the transparent protective substrate 40. It suffices to intervene in at least one of these. When the touch panel is on-cell, the touch panel and the liquid crystal display cell are integrated. As a specific example, the liquid crystal display cell 10 of the liquid crystal display device of FIG. 1 may be replaced with an on-cell.

  According to the liquid crystal display device shown in FIGS. 1 and 2, since the cured body of the curable resin composition of the present embodiment is provided as the transparent resin layer 31 or 32, it has impact resistance, is clear and has no double reflection. An image with high contrast is obtained.

  The liquid crystal display cell 10 can be made of a liquid crystal material well known in the art. Also, depending on the control method of the liquid crystal material, it is classified into TN (Twisted Nematic) method, STN (Super-twisted nematic) method, VA (Virtual Alignment) method, IPS (In-Place-Switching) method, etc. In the form, a liquid crystal display cell using any control method may be used.

  As the polarizing plates 20 and 22, a polarizing plate common in this technical field can be used. The surfaces of these polarizing plates may be subjected to treatments such as antireflection, antifouling, and hard coat. Such surface treatment may be performed on one side of the polarizing plate or on both sides thereof.

  As the touch panel 30, what is generally used in this technical field can be used.

  The transparent resin layer 31 or 32 can be formed with a thickness of 0.02 mm to 3 mm, for example. In particular, the curable resin composition of the present embodiment is effective for thick films, and can be suitably used when the transparent resin layer 31 or 32 having a thickness of 0.1 mm or more is formed.

  As the transparent protective substrate 40, a general optical transparent substrate can be used. Specific examples thereof include inorganic plates such as glass plates and quartz plates, resin plates such as acrylic plates and polycarbonate plates, and resin sheets such as thick polyester sheets. When high surface hardness is required, a plate such as glass or acrylic is preferable, and a glass plate is more preferable. The surface of these transparent protective substrates may be subjected to treatments such as antireflection, antifouling, and hard coating. Such surface treatment may be performed on one side of the transparent protective substrate or on both sides. A plurality of transparent protective substrates can be used in combination.

  The backlight system 50 typically includes a reflecting unit such as a reflecting plate and an illuminating unit such as a lamp.

  The liquid crystal display device of FIG. 1 described above includes the step of interposing the curable resin composition of the present embodiment between the image display unit and the protective panel, and the curable resin by irradiating light from the protective panel surface side. And a step of curing the composition to form a transparent resin layer.

  As a method of interposing the curable resin composition between the image display unit and the protective panel, for example, using a dispenser, the curable resin composition is applied on the image display unit or the protective panel, and then vacuum (reduced pressure) is applied. Alternatively, a method of pasting at atmospheric pressure, or a method of casting a curable resin composition between an image display unit and a protective panel arranged at a certain interval may be mentioned. In addition, when casting a curable resin composition, you may form a dam around an image display unit and a protection panel.

  The liquid crystal display device of FIG. 2 described above includes a step of interposing the curable resin composition of the present embodiment between the image display unit and the touch panel and / or between the touch panel and the protective panel, And irradiating light from the protective panel surface side to cure the curable resin composition and forming a transparent resin layer. As a method of interposing the curable resin composition, the same method as in the liquid crystal display device of FIG.

The light irradiation, for example, using an ultraviolet irradiation device can be carried out under the conditions of exposure ^{500mJ / cm 2 ~5000mJ / cm 2} . The exposure amount refers to a value obtained by multiplying the illuminance that can be measured by an ultraviolet illuminance meter UV-M02 (receiver: UV-36) manufactured by Oak Co., Ltd., by the irradiation time (seconds). The light source for ultraviolet irradiation may be a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, an LED lamp or the like, but it is preferable to use a high pressure mercury lamp or a metal halide lamp.

  In the case of light irradiation, irradiation from the protective panel surface side and irradiation from the side surface may be used in combination. Moreover, hardening can also be accelerated | stimulated by heating the laminated body containing a curable resin composition simultaneously with light irradiation. Moreover, in the manufacturing method of the liquid crystal display device described above, the case where the curable resin composition is cured by light irradiation, that is, the case where the curable resin composition contains a photopolymerization initiator (D1) has been described. When the curable resin composition contains (D2) a thermal polymerization initiator, the curable resin composition may be cured by heat.

The liquid crystal display device that can be manufactured by using the curable resin composition of the present embodiment has been described above, but the image display that can be manufactured by using the curable resin composition of the present embodiment. The application apparatus is not limited to this, and can be applied to a plasma display (PDP), a cathode ray tube (CRT), a field emission display (FED), an organic EL display, a 3D display, electronic paper, and the like.
In particular, when the image display device is 10 inches or larger, it is more preferable to produce a transparent resin layer using the curable resin composition of the present embodiment.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

First, preparation examples of a resin composition that can be used in an image display device to which the present invention is applied will be described below. In the following examples, the weight average molecular weight was measured using gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and determined using polystyrene as a standard substance. The GPC conditions are shown below.
(GPC conditions)
Pump: Hitachi L-6000 type [manufactured by Hitachi, Ltd.]
Detector: Hitachi L-3300 RI [manufactured by Hitachi, Ltd.]
Column: Gelpack GL-R420 + Gelpack GL-R430 + Gelpack GL-R440 (3 in total) (manufactured by Hitachi Chemical Co., Ltd., trade name)
Eluent: THF
Measurement temperature: 25 ° C

(Synthesis of acrylic polymer 1)
A reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping device and nitrogen injection tube was charged with 575.0 g of methyl ethyl ketone and heated from room temperature (25 ° C.) to 100 ° C. in 50 minutes while replacing nitrogen at 150 ml / min. .
Thereafter, while maintaining this temperature, 805.0 g of 2-ethylhexyl acrylate and 345.0 g of 2-hydroxyethyl acrylate were used as monomers, and 17.25 g of t-butylperoxy-2-ethylhexanoate was dissolved in them. A solution was prepared, and the solution was added dropwise over 150 minutes. After completion of the addition, the reaction was further continued for 1 hour.
Subsequently, a solution in which 2.5 g of azobisisobutyronitrile was dissolved in 253.0 g of methyl ethyl ketone was prepared, and this solution was added dropwise over 30 minutes. After completion of the addition, the temperature was raised to 120 ° C. in 30 minutes, The reaction was performed for 2 hours.
Finally, methyl ethyl ketone was distilled off to obtain a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 20,000).

(Synthesis of acrylic polymer 2)
Into a reaction vessel equipped with a cooling tube, a thermometer, a stirring device, a dropping device and a nitrogen injection tube, 84.0 g of 2-ethylhexyl acrylate, 36.0 g of 2-hydroxyethyl acrylate and 150.0 g of methyl isobutyl ketone are taken as initial monomers. While replacing with nitrogen at 100 ml / min, heating was performed from room temperature (25 ° C.) to 70 ° C. in 15 minutes.
Thereafter, while maintaining this temperature, 21.0 g of 2-ethylhexyl acrylate and 9.0 g of 2-hydroxyethyl acrylate were used as additional monomers, and a solution in which 0.6 g of lauroyl peroxide was dissolved therein was prepared. Was added dropwise over 60 minutes, and the reaction was further continued for 2 hours after the completion of the dropwise addition.
Subsequently, methyl isobutyl ketone was distilled off to obtain a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 200,000).

(Synthesis of acrylic polymer 3)
A reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping device and nitrogen injection tube was charged with 575.0 g of methyl ethyl ketone and heated from room temperature (25 ° C.) to 90 ° C. in 50 minutes while replacing nitrogen at 150 ml / min. .
Thereafter, while maintaining this temperature, 805.0 g of 2-ethylhexyl acrylate and 345.0 g of 2-hydroxyethyl acrylate were used as monomers, and 11.5 g of t-butylperoxy-2-ethylhexanoate was dissolved in them. A solution was prepared, and the solution was added dropwise over 150 minutes. After completion of the addition, the reaction was further continued for 1 hour.
Subsequently, a solution in which 2.88 g of azobisisobutyronitrile was dissolved in 287.5 g of methyl ethyl ketone was prepared, this solution was added dropwise over 30 minutes, and the temperature was raised to 120 ° C. within 30 minutes after the completion of the addition. The reaction was performed for 2 hours.
Finally, methyl ethyl ketone was distilled off to obtain a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 40,000).

(Synthesis of acrylic polymer 4)
In a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping device and nitrogen injection tube, 575.0 g of methyl ethyl ketone was taken, and the pressure in the flask was increased to 2.5 MPa. Heated to ° C.
Thereafter, while maintaining this temperature, 805.0 g of 2-ethylhexyl acrylate and 345.0 g of 2-hydroxyethyl acrylate were used as monomers, and 23.0 g of t-butylperoxy-2-ethylhexanoate was dissolved in them. A solution was prepared, and the solution was added dropwise over 150 minutes. After completion of the addition, the reaction was further continued for 1 hour.
Subsequently, a solution in which 2.5 g of azobisisobutyronitrile was dissolved in 253.0 g of methyl ethyl ketone was prepared, and this solution was added dropwise over 30 minutes. After completion of the addition, the temperature was further maintained for 2 hours to complete the reaction.
Finally, methyl ethyl ketone was distilled off to obtain a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 9,000).

(Synthesis of acrylic polymer 5)
A reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping device and nitrogen injection tube was charged with 575.0 g of methyl isobutyl ketone, and the flask was pressurized to 2.5 MPa and at room temperature (25 ° C.) for 50 minutes. To 135 ° C.
Thereafter, while maintaining this temperature, 805.0 g of 2-ethylhexyl acrylate and 345.0 g of 2-hydroxyethyl acrylate were used as monomers, and 23.0 g of t-butylperoxy-2-ethylhexanoate was dissolved in them. A solution was prepared, and the solution was added dropwise over 150 minutes. After completion of the addition, the reaction was further continued for 1 hour.
Subsequently, a solution in which 2.5 g of azobisisobutyronitrile was dissolved in 253.0 g of methyl ethyl ketone was prepared, and this solution was added dropwise over 30 minutes. After completion of the addition, the temperature was raised to 142 ° C. over 30 minutes. I let you.
Finally, methyl isobutyl ketone was distilled off to obtain a copolymer of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate (weight average molecular weight 7,000).

(Synthesis of polyurethane acrylate 1)
180 g (0.09 mol) of polypropylene glycol (molecular weight 2,000), 2.33 g (0.02 mol) of 2-hydroxyethyl acrylate, polymerization in a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and air injection tube As an inhibitor, 0.5 g of p-methoxyphenol and 0.05 g of dibutyltin dilaurate as a catalyst were taken. After raising the temperature to 70 ° C. while flowing air, 22.2 g (0.1 mol) of isophorone diisocyanate was uniformly added dropwise over 2 hours while stirring at 70 to 75 ° C. to carry out the reaction.
When the reaction was completed for 5 hours after completion of the dropwise addition, the reaction was terminated by confirming that the isocyanate had disappeared by IR measurement. Polyurethane acrylate having polypropylene glycol and isophorone diisocyanate as repeating units and having an ethylenically unsaturated bond ( A weight average molecular weight of 20,000 and an average number of functional groups = 2 (calculated value)) were obtained.

(Synthesis of polyurethane acrylate 2)
Polytetramethylene glycol (molecular weight 850) 520.8 g (0.613 mol), diethylene glycol 1.06 g (0.01 mol), unsaturated fatty acid in a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and air injection tube Hydroxyalkyl ester-modified ε-caprolactone (Placcel FA2D: Daicel Chemical Industries, Ltd.) 275.2 g (0.8 mol), p-methoxyphenol 0.5 g as a polymerization inhibitor, and dibutyltin dilaurate 0.3 g as a catalyst It was. After raising the temperature to 70 ° C. while flowing air, 222 g (1 mol) of isophorone diisocyanate was uniformly dropped over 2 hours while stirring at 70 to 75 ° C. to carry out the reaction.
After the completion of the dropping, the reaction was completed for 5 hours, and the reaction was terminated by confirming that the isocyanate had disappeared by IR measurement. Polyurethane having polytetramethylene glycol and isophorone diisocyanate as repeating units and having an ethylenically unsaturated bond Acrylates (weight average molecular weight 7,000, average number of functional groups = 2 (calculated value)) were obtained.

(Synthesis of polyurethane acrylate 3)
In a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and air injection tube, polypropylene glycol (molecular weight 2,000) 186.5 g (0.093 mol), 2-hydroxyethyl acrylate 1.60 g (0.014 mol) Then, 0.5 g of p-methoxyphenol was used as a polymerization inhibitor and 0.05 g of dibutyltin dilaurate was used as a catalyst. After raising the temperature to 70 ° C. while flowing air, 22.2 g (0.1 mol) of isophorone diisocyanate was uniformly added dropwise over 2 hours while stirring at 70 to 75 ° C. to carry out the reaction.
When the reaction was completed for 5 hours after completion of the dropwise addition, the reaction was terminated by confirming that the isocyanate had disappeared by IR measurement. Polyurethane acrylate having polypropylene glycol and isophorone diisocyanate as repeating units and having an ethylenically unsaturated bond ( A weight average molecular weight of 30,000 and an average number of functional groups = 2 (calculated value)) were obtained.

(Synthesis of polyurethane acrylate 4)
Polytetramethylene glycol (molecular weight 850) 520.8 g (0.613 mol), diethylene glycol 1.06 g (0.01 mol), unsaturated fatty acid in a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and air injection tube Hydroxyalkyl ester modified ε-caprolactone (Placcel FA2D: Daicel Chemical Industries, Ltd. trade name) 137.6 g (0.4 mol), butanol 34.9 g (0.47 mol), p-methoxyphenol 0.5 g as a polymerization inhibitor, As a catalyst, 0.3 g of dibutyltin dilaurate was taken. After raising the temperature to 70 ° C. while flowing air, 222 g (1 mol) of isophorone diisocyanate was uniformly dropped over 2 hours while stirring at 70 to 75 ° C. to carry out the reaction.
After the completion of the dropping, the reaction was completed for 5 hours, and the reaction was terminated by confirming that the isocyanate had disappeared by IR measurement. Polyurethane having polytetramethylene glycol and isophorone diisocyanate as repeating units and having an ethylenically unsaturated bond Acrylates (weight average molecular weight 7,000, average number of functional groups = 1 (calculated value)) were obtained.

(Synthesis of polyurethane acrylate 5)
Polytetramethylene glycol (molecular weight 850) 520.8 g (0.613 mol), diethylene glycol 1.06 g (0.01 mol), unsaturated fatty acid in a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and air injection tube Hydroxyalkyl ester modified ε-caprolactone (Placcel FA2D: Daicel Chemical Industries, Ltd. trade name) 137.6 g (0.4 mol), butanol 34.9 g (0.47 mol), p-methoxyphenol 0.5 g as a polymerization inhibitor, As a catalyst, 0.3 g of dibutyltin dilaurate was taken. After raising the temperature to 70 ° C while flowing air, stirring at 70 to 75 ° C, TMDI (mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, mixing ratio: 4: 6 (mass ratio)) Diisocyanate 209.8 g (1 mol) was uniformly added dropwise over 2 hours to carry out the reaction.
After the completion of the dropwise addition, the reaction was terminated after confirming that the isocyanate had disappeared by IR measurement when the reaction was completed for 5 hours. Polyurethane acrylate having polytetramethylene glycol and TMDI as repeating units and having an ethylenically unsaturated bond (Weight average molecular weight 7,000, average number of functional groups = 1 (calculated value)) was obtained.

(Synthesis of polyurethane acrylate 6)
Polytetramethylene glycol (molecular weight 850) 520.8 g (0.613 mol), diethylene glycol 1.06 g (0.01 mol), unsaturated fatty acid in a reaction vessel equipped with a cooling tube, thermometer, stirring device, dropping funnel and air injection tube Hydroxyalkyl ester modified ε-caprolactone (Placcel FA2D: Daicel Chemical Industries, Ltd. trade name) 68.8 g (0.2 mol), butanol 52.3 g (0.71 mol), p-methoxyphenol 0.5 g as a polymerization inhibitor, As a catalyst, 0.3 g of dibutyltin dilaurate was taken. After raising the temperature to 70 ° C while flowing air, stirring at 70 to 75 ° C, TMDI (mixture of 2,2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, mixing ratio: 4: 6 (mass ratio)) Diisocyanate 209.8 g (1 mol) was uniformly added dropwise over 2 hours to carry out the reaction.

  After completion of the dropwise addition, the reaction was terminated after confirming that the isocyanate had disappeared by IR measurement when the reaction was completed for 5 hours. (Weight average molecular weight 7,000, average number of functional groups = 0.5 (calculated value)) was obtained.

(Examples 1-13 and Comparative Examples 1-7)
In the mixing ratios shown in Table 1 and Table 2, the components (A) to (D) were blended and mixed by stirring to prepare curable resin compositions of Examples 1 to 13 and Comparative Examples 1 to 7. In addition, the unit of the numerical value about (A)-(D) component in a table | surface is a mass part. “The amount of component (C) in the table” in the table indicates the amount of component (C) relative to the total amount of component (A), component (B) and component (C).

  The test shown below was done about the curable resin composition obtained by the Example and each comparative example. The results are shown in Tables 1 and 2.

(viscosity)
The viscosity of the curable resin composition was measured at 25 ° C. using an E-type viscometer (RE-80L manufactured by Toki Sangyo).

(Moisture and heat resistance reliability)
A curable resin composition is dropped on a 2-inch glass substrate, another glass substrate is bonded through a 175 μm spacer, and ultraviolet rays are irradiated at 2,000 mJ / cm ² using an ultraviolet irradiation device. I got a piece. This test piece was placed in a test bath of 85 ° C./85% RH for 50 hours, peeled off, and visually evaluated for the presence or absence of bubbles, and evaluated according to the following criteria.
A: No visual change B: Peeled off visually, bubbles were confirmed

(optical properties)
A curable resin composition is dropped onto a polyethylene terephthalate film (hereinafter referred to as a PET film) whose surface has a thickness of 50 μm manufactured by Fujimori Kogyo Co., Ltd., and another PET is formed so that the film thickness is 175 μm. The films were bonded together, and a transparent film in which the curable resin composition was cured by irradiating ultraviolet rays at 2,000 mJ / cm ² using an ultraviolet irradiation device was produced. The PET film was peeled off, and the transmittance of the transparent film at a wavelength of 400 nm was measured using a spectrophotometer (Shimadzu Corporation UV-2400PC). Moreover, the haze of this transparent film was measured using the haze meter (Suga Test Instruments Co., Ltd. HGM-2).

(Curing shrinkage)
A curable resin composition is dropped onto a PET film, and another PET film is bonded so as to have a film thickness of 175 μm, and an ultraviolet ray is radiated at 2,000 mJ / cm ² using an ultraviolet ray irradiation device. A transparent film in which the product was cured was produced. The specific gravity of this transparent film and the resin composition before curing was measured using an electronic hydrometer (Alpha Mirage SD-200L), and the curing shrinkage was calculated from the following formula and evaluated according to the following criteria. .
Curing shrinkage (%) = {(specific gravity of the resin composition after curing−specific gravity of the resin composition before curing) / specific gravity of the resin composition after curing} × 100
A: Less than 1.5% B: 1.5% or more and less than 3.0% C: 3.0% or more and less than 5.0% D: 5.0% or more

  DESCRIPTION OF SYMBOLS 1 ... Image display unit, 10 ... Liquid crystal display cell, 20, 22 ... Polarizing plate, 30 ... Touch panel, 31, 32 ... Transparent resin layer, 40 ... Transparent protective substrate, 50 ... Backlight system.

Claims (6)

(A) an acrylic polymer,
(B) a polymer having an ethylenically unsaturated bond in the molecule;
(C) a monomer having one ethylenically unsaturated group in the molecule, and (D) a polymerization initiator,
Containing
The liquid curable resin composition whose content of (C) component is 5-25 mass% with respect to the total amount of (A) component, (B) component, and (C) component.   The liquid curable resin composition according to claim 1, wherein the component (B) is a urethane polymer having a (meth) acryloyl group.   The liquid curable resin composition of Claim 1 or 2 which does not contain an organic solvent substantially and whose viscosity in 25 degreeC is 500-5000 mPa * s. An image display device comprising: an image display unit; and a protection panel,
A step of interposing the liquid curable resin composition according to any one of claims 1 to 3 between the image display unit and the protective panel;
And a step of curing the liquid curable resin composition by irradiating light from the protective panel surface side. A method for manufacturing an image display device comprising an image display unit, a touch panel, and a protection panel,
The step of interposing the liquid curable resin composition according to any one of claims 1 to 3 between the image display unit and the touch panel and / or between the touch panel and the protective panel;
And a step of curing the liquid curable resin composition by irradiating light from the protective panel surface side.   An image display device manufactured by the manufacturing method according to claim 4.

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