JP5650347B1 - Resin molded body, protective plate for display and touch panel substrate, and self-repairing method of resin molded body - Google Patents

Abstract

Disclosed is a resin molded body that is lightweight and safe and suitable for a flexible display, particularly a resin molded body that has a very high surface hardness and that has self-healing properties against irregularities such as scratches. In a transparent resin molded product having a thickness of 0.5 mm or more obtained by photocuring a photopolymerizable composition [I], the following requirements (α) and (β) are satisfied: Resin molded body. (Α) The pencil hardness of the resin molded body surface is 8H or more. (Β) A test in which a load of 160 g is applied to # 0000 steel wool having a diameter of 1 cm and reciprocated 5000 times at a stroke width of 5 cm and a speed of 5 cm / sec. The haze ratio (β2 / β1) is 0.9 or less when the haze after leaving for 3 days at 23 ° C. and 50% RH is β2 (%). [Selection figure] None

Description

  The present invention relates to a resin molded product obtained by photocuring a photopolymerizable composition, and in particular, a sheet-shaped or film-shaped resin molded product having excellent optical characteristics, thermal characteristics, and mechanical characteristics. In particular, the present invention relates to a resin molded body useful as a resin substrate or a protective plate for a display.

  Conventionally, as a substrate for a display, a glass substrate is often used. For example, a chemically strengthened glass substrate having a thickness of about 0.5 to 2 mm is widely used as a protective plate. As the touch panel substrate, a glass substrate having a thickness of about 0.2 to 1.1 mm is widely used. Furthermore, a glass substrate having a thickness of about 0.2 to 0.7 mm is widely used in liquid crystal displays and organic electroluminescence (organic EL) displays.

  On the other hand, in recent years, resin substrates have begun to be used from the viewpoint of weight reduction and safety, and for the purpose of manufacturing flexible displays. Actually, polymethyl methacrylate (PMMA), polycarbonate, polyethylene terephthalate (PET), or a substrate obtained by applying a hard coat to these resin sheets is used. Such resin substrates have not only optical performance such as light transmittance and birefringence, but also thermal properties such as heat resistance and linear expansion coefficient, mechanical properties such as surface hardness and flexural modulus, water absorption and specific gravity, and resistance to resistance. High processability such as chemicals and solvent resistance is required.

  In order to satisfy these various properties, many resins have been proposed regardless of thermoplasticity or thermosetting. In particular, a resin substrate having a surface hardness improved by hard-coating a sheet made of these resins has been proposed, but the present situation is that a surface hardness exceeding glass is not obtained.

Among recent proposals, a resin molded product obtained by photocuring a specific photopolymerizable composition can also be seen.
For example, it is disclosed that a photopolymerizable composition comprising a polyfunctional urethane (meth) acrylate having an alicyclic structure and a polyfunctional (meth) acrylate having an alicyclic structure gives a resin molded article having high pencil hardness. (For example, refer to Patent Document 1).
A photopolymerizable composition comprising a monofunctional (meth) acrylate having an alicyclic structure, a polyfunctional urethane (meth) acrylate having an alicyclic structure, and a polyfunctional (meth) acrylate having an alicyclic structure has optical characteristics. In addition, it is disclosed that a resin molded body having excellent thermomechanical properties is provided (for example, see Patent Document 2).

JP 2006-193596 A JP 2007-204736 A

  However, even with these disclosed techniques, it is very difficult to obtain a resin substrate having a surface hardness that is high enough to replace glass, for example, a pencil hardness of 8H. Generally, the pencil hardness of glass is 8H or more, and the pencil hardness of glass whose surface is chemically strengthened is 9H or more. However, even in the technique disclosed in Patent Document 1, the highest pencil hardness is 7H, and in the technique disclosed in Patent Document 2, the highest pencil hardness is 6H. That is, with these disclosed technologies, a resin substrate that is not easily damaged as much as glass and has a high hardness cannot be obtained. The most commercially available pencil has the highest hardness of 10H.

  If the surface hardness of the substrate is insufficient, not only the final product is easily damaged, but also scratches and fine dents are generated during transportation and in the manufacturing process of the display device. In consideration of recent increases in display area and resolution, defects resulting from scratches and dents significantly impair the quality of the product. In addition, in the touch panel substrate, defects such as cracks and pinholes are likely to occur in the conductive film formed on the resin molded body. In order to improve the surface hardness, a method of hard-coating the surface of the resin molded body is generally used. However, a resin molded body that is easily charged tends to adhere foreign matter, and it is extremely difficult to eliminate foreign matter defects on the coated surface. It is. Multi-layering with a hard coat or protective film leads to an increase in cost.

  Further, in the organic EL display, the surface smoothness of the substrate greatly affects the light emission characteristics and the lifetime of the device. The surface hardness of the substrate is particularly important because minute dents and protrusions due to scratches and foreign matters cause deterioration of the element and display defects such as black spots. Further, if the surface hardness is insufficient, a minute surface roughness occurs when an electrode or an organic EL layer is formed on the substrate, and sufficient light emission characteristics cannot be obtained. In order to achieve high brightness and low power consumption, it is necessary to improve the surface hardness of the resin substrate.

  Furthermore, when the resin molded body is used as a film roll, the surface hardness becomes a problem. That is, when the surface hardness is low, the scratches with the transport roll and the scratches between the films in the winding process increase. In order to improve the surface hardness, methods such as hard coat treatment, affixing a protective film, and inserting slip sheets are conceivable. However, these methods cause cost increase, so these treatments It is preferable to increase the surface hardness of the resin molded body and to be wound around the core material without any process.

The problem mentioned above was the reason for greatly reducing the opportunity to use a resin substrate instead of glass.
Therefore, in the present invention, under such a background, a resin molded body that is lightweight and safe and suitable for a flexible display, in particular, has a very high surface hardness, and has self-repairing property against unevenness such as scratches. It aims at providing the resin molding which has.

  As a result of intensive studies by the present inventors to solve the above problems, a transparent resin molded product having a relatively thick thickness of 0.5 mm or more obtained by photocuring the photopolymerizable composition [I]. However, the resin molded body having a pencil hardness equal to or higher than that of glass and having a decrease in haze with time even in a predetermined scratch resistance test is high in hardness, and the scratches on the surface of the resin are The present invention was completed by finding that the resin molded body disappears due to self-healing properties.

That is, the gist of the present invention is that a transparent resin molded body having a thickness of 0.5 mm or more obtained by photocuring the photopolymerizable composition [I] satisfies the following requirements (α) and (β): It is related with the resin molding characterized by this.
(Α) The pencil hardness of the resin molded body surface is 8H or more.
(Β) In a test in which a load of 160 g is applied to # 0000 steel wool having a diameter of 1 cm and reciprocated 5000 times at a stroke width of 5 cm and a speed of 5 cm / second, the haze immediately after the test is β1 (%). The haze ratio (β2 / β1) is 0.9 or less when the haze after leaving for 3 days at 23 ° C. and 50% RH is β2 (%).

  Moreover, in this invention, the protective plate for displays which consists of the said resin molding, Furthermore, the touchscreen board | substrate by which a transparent conductive film is formed into a film on the single side | surface of the said resin molding is provided.

  Furthermore, the present invention also provides a self-repairing method for a resin molded body that repairs scratches generated in the resin molded body.

  The resin molded body of the present invention is excellent in optical characteristics, thermal characteristics, and mechanical characteristics, has a particularly high surface hardness, and can be a resin molded body suitable for a protective plate and a touch panel substrate. In particular, since it has self-healing properties, it is suitable as a substrate located in the outermost layer of the display.

The present invention is described in detail below.
In the present specification, “(meth) acrylate” is a general term for acrylate and methacrylate.

  The resin molded body of the present invention satisfies the above requirements (α) and (β) in a transparent resin molded body having a thickness of 0.5 mm or more obtained by photocuring the photopolymerizable composition [I]. Is.

  The thickness of the resin molded body of the present invention is relatively thick, and the thickness is 0.5 mm or more, preferably 0.5 to 5 mm, more preferably 0.6 to 4 mm, still more preferably 0.6 to 3 mm, Especially preferably, it is 0.7-2 mm, Most preferably, it is 0.7-1 mm. If the thickness is too thin, the rigidity as a display substrate or a protective plate tends to be inferior, and if it is too thick, the display tends to be thick and heavy.

  The higher the pencil hardness of the surface of the resin molded body of the present invention is, the higher the glass substitution is considered. In the present invention, the pencil hardness is 8H or higher, more preferably 9H or higher, and particularly preferably 10H or higher. In addition, about evaluation of pencil hardness at present, since the commercially available pencil is up to 10H, evaluation exceeding 10H cannot be performed, but as a resin molded body, the surface hardness is higher. preferable.

  Here, in the present invention, the pencil hardness is evaluated in accordance with JIS K-5600-5-4 by testing with a load of 750 g and immediately after rubbing the pencil and at 23 ° C. and 50% RH after rubbing the pencil. Then, the scratches on the surface after standing for 3 days are evaluated visually, and the pencil hardness without scratches is measured.

  Usually, the thickness of the resin molded body obtained by photocuring is more difficult to produce, and the internal reaction rate is low in the thickness direction, and accordingly it is difficult to increase the surface hardness. Although it is conceivable, in the present invention, even if it is thick, a high surface hardness could be achieved, and an unprecedented resin molded body could be obtained.

  Furthermore, in this invention, it has a time-dependent fall of the haze in a predetermined | prescribed abrasion resistance test with respect to a resin molding.

  That is, in a test in which a load of 160 g is applied to # 0000 steel wool having a diameter of 1 cm and the resin molded body is reciprocated 5000 times at a stroke width of 5 cm and a speed of 5 cm / sec, the haze immediately after the test is β1 (%). When the haze after being allowed to stand at 23 ° C. and 50% RH for 3 days is β2 (%), the resin molded body of the present invention has a haze ratio (β2 / β1) of 0.9 or less. It can be confirmed that the scratches that have entered the surface of the resin molded body have disappeared due to the self-repairing property of the resin. If there is self-healing property, the haze will decrease with time, and the greater the decrease in haze, the stronger the self-healing property. The preferable range of the haze ratio (β2 / β1) is 0.8 or less, more preferably 0.7 or less, and particularly preferably 0.6 or less. When the haze ratio (β2 / β1) exceeds 0.9, the self-repairing property tends to be low.

The self-repairing property as used herein means the ability to fill a scratch or dent by movement of the resin component even if the surface of the resin molded body has a scratch or a dent. In general, rubbery materials have the ability to repair dents, but it is very difficult to develop such a capability with a hard and transparent resin molding. In addition, it is known that urethane-based coating agents have a self-healing ability of scratches, but these are related to coating agents, and it is difficult to express such self-repairing ability with a relatively thick resin molding. Met.
That is, the greatest feature of the present invention lies in that a high surface hardness and self-repairing property are expressed while being a relatively thick resin molded body (single plate).

  Although there is a limit to the size of a scratch that can be repaired (depth, width, etc.), what is required of a display substrate is the ability to repair scratches from submicrons to hundreds of microns. In the case of a protective plate, there are many small scratches of several tens of microns that can be visually recognized. The time for repairing the flaw varies depending on the size of the flaw and varies from an instant to several months. In the case of a protective plate, it is preferable that visual confirmation is not possible within a few days.

In the resin molded body of the present invention, the light transmittance is preferably 85% or more, particularly 88% or more, more preferably 90% or more, from the viewpoint of increasing the brightness or definition of the display. preferable. If the light transmittance is too small, the brightness of the display tends to decrease. The upper limit of the light transmittance is usually 99%.
Here, the light transmittance (%) is the total light transmittance measured according to JIS K 7375.

Further, the haze of the resin molded body of the present invention is preferably 1% or less, particularly 0.7% or less, more preferably 0. It is preferable that it is 5% or less. If the haze is too large, the definition of the display tends to decrease. The lower limit of haze is usually 0.001%.
Here, haze is a value measured according to JIS K 7136.

The resin molded body of the present invention preferably has a surface roughness Ra of at least one surface of 20 nm or less, particularly 15 nm or less, more preferably 10 nm or less from the viewpoint of display quality of the display. If the surface roughness is too large, the quality of the display tends to deteriorate. The lower limit value of the surface roughness Ra is usually 1 nm.
In the present invention, the surface roughness Ra is measured based on JIS B0601: 2001.

  The resin molded body of the present invention preferably has a flexural modulus of 3 GPa or more (25 ° C.), particularly 3 to 5 GPa from the viewpoint of thinning the display. If the flexural modulus is too small, the toughness of the resin molded product tends to decrease, and the display tends to bend or swell. In addition, when a bending elastic modulus is too large, there exists a tendency for manufacture of a flexible display to become difficult.

The resin molded body of the present invention preferably has a glass transition temperature of 200 ° C. or higher, more preferably 210 ° C. or higher, and particularly preferably 220 ° C. or higher from the viewpoint of display reliability. When the glass transition temperature is too low, the heat resistance tends to decrease, and the display tends to be difficult to produce. The upper limit of the glass transition temperature is 400 ° C.
Here, the glass transition temperature is a value measured according to JIS K 7244.

  The resin molded body of the present invention preferably has a saturated water absorption of 0.5 to 2%, particularly 0.8 to 1.7%, more preferably 1 to 1.5%. If the saturated water absorption is too small, the self-repairing property tends to be lowered, and if it is too much, the substrate tends to be warped or swelled.

In the present invention, in satisfying the above various physical properties, it can be obtained by photocuring the photopolymerizable composition. Among them, as the photopolymerizable composition, the following components (A), (B), and (C It is preferable to use a photopolymerizable composition [I] containing). Further, the content ratio (A: B) of the component (A) and the component (B) is preferably 30:70 to 60:40 in terms of weight ratio in terms of a good balance of physical properties such as surface hardness and saturated water absorption. .
(A) Polyfunctional urethane (meth) acrylate having alicyclic structure (B) Polyfunctional (meth) acrylate having alicyclic structure (excluding component (A))
(C) Photopolymerization initiator In addition, polyfunctional here means having two or more (meth) acryloyl groups in a molecule | numerator.

  Component (A) is a urethane (meth) acrylate containing two or more (meth) acryloyl groups in the molecule. Since it is polyfunctional, the curing rate is improved, and a resin molded product can be obtained with high productivity. Moreover, a crosslinked resin can be formed by photocuring, and a resin molding with high surface hardness can be obtained. It should be noted that component (A) has a urethane group in the molecule and exhibits self-healing properties. The reason for this is not clear, but it is presumed that the molecular chains broken by the scratches recombine due to hydrogen bonding. In addition, a flexible resin molded article excellent in mechanical strength such as bending elastic modulus and impact resistance can be obtained by the hydrogen bond. The improvement of the surface hardness is manifested particularly with a tetrafunctional or higher urethane (meth) acrylate. In addition, component (A) has an alicyclic structure in the molecule, and the water absorption rate of the resin molded product is reduced by this alicyclic structure.

  Since component (B) is also a polyfunctional (meth) acrylate, a highly heat-resistant resin molded product is provided. Although the effect of improving heat resistance is greater than that of the component (A) urethane (meth) acrylate, this monomer alone is too brittle because it becomes a glass-like crosslinked resin. In addition to surface hardness and self-healing property, heat resistance and flexibility are achieved by containing and copolymerizing component (A) urethane (meth) acrylate and component (B) polyfunctional (meth) acrylate. Can be obtained. If the number of functional groups in component (B) is excessively large, the balance between heat resistance and flexibility tends to be lost, so component (B) is preferably bifunctional and more preferably methacrylate. . The component (B) also has an alicyclic structure, and this alicyclic structure also reduces the saturated water absorption rate of the resin molded body.

  The content ratio (A: B) of the component (A) and the component (B) is preferably 30:70 to 60:40 (weight ratio). If the amount of component (A) is too small, surface hardness and self-healing properties tend to decrease. Conversely, if the amount of component (A) is too large, it becomes difficult to produce a resin molded product because of high viscosity, and Saturated water absorption tends to increase. A preferable range of the content ratio is 35:65 to 55:45 (weight ratio), and particularly preferably 40:60 to 50:50 (weight ratio).

  The photopolymerizable composition [I] of the present invention preferably has a viscosity at 23 ° C. of 1 to 5 Pa · s. More preferably, it is 2-4 Pa * s, More preferably, it is 2-3 Pa * s. If the viscosity is too low, unpolymerized monomers tend to remain in the molding step, and conversely, if too high, handling tends to be difficult. Examples of the method for adjusting the viscosity include appropriately controlling the types and blending amounts of the components (A) and (B).

The number average molecular weight of component (A) is preferably 200 to 5,000. More preferably, it is 400-3000, More preferably, it is 500-1000. When the number average molecular weight is too small, curing shrinkage increases and birefringence tends to occur. On the other hand, if it is too large, the crosslinkability tends to decrease and the heat resistance tends to decrease. The number average molecular weight is measured as follows.
That is, the number average molecular weight (Mn) is a number average molecular weight in terms of standard polystyrene molecular weight, and can be measured by high performance liquid chromatography (“Waters 2695 (main body)” and “Waters 2414 (detector)” manufactured by Nippon Waters). Column: Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / pack, filler material: styrene-divinylbenzene copolymer, It is a value measured by using three series of filler particle diameters: 10 μm).

  The polyfunctional urethane (meth) acrylate having an alicyclic structure as the component (A) is prepared by using a polyisocyanate compound having an alicyclic structure and a hydroxyl group-containing (meth) acrylate, if necessary, using a catalyst such as dibutyltin dilaurate. It can be obtained by reacting.

  Specific examples of the polyisocyanate compound having an alicyclic structure include, for example, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, hydrogenated xyly Examples include a diisocyanate, a hydrogenated diphenylmethane diisocyanate, and a trimer compound of isophorone diisocyanate. Of these, isophorone diisocyanate is preferred in terms of self-healing properties.

  Specific examples of the hydroxyl group-containing (meth) acrylate include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 2-hydroxy-3- (meth). Examples include acryloyloxypropyl (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol tri (meth) acrylate. Of these, pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol tri (meth) acrylate are preferable in terms of surface hardness.

  Two or more polyfunctional urethane (meth) acrylates obtained by the reaction of a polyisocyanate compound having an alicyclic structure and a hydroxyl group-containing (meth) acrylate may be used in combination. Among these polyfunctional urethane (meth) acrylates, acrylate is preferable from the viewpoint of curing speed, tetrafunctional or higher is more preferable from the viewpoint of heat resistance, and it is represented by the following formulas (1) to (4) from the viewpoint of surface hardness. Particularly preferred is a tetrafunctional or higher functional urethane acrylate having an alicyclic structure. The upper limit of polyfunctionality is usually 18, preferably 6 functionalities.

Examples of the polyfunctional (meth) acrylate (excluding (A)) having an alicyclic structure as the component (B) include bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane = Di (meth) acrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = di (meth) acrylate, bis (hydroxy) tricyclo [5.2.1.0 ^2,6 ] decane = Acrylate methacrylate, bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = acrylate methacrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = di (meth) acrylate, bis (hydroxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = di (meth) acrylate, bis (hydroxy) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . 0 ^9,13 ] pentadecane = acrylate methacrylate, bis (hydroxymethyl) pentacyclo [6.5.1.1 ^3,6 . 0 ^2,7 . ^0,13 ] pentadecane = acrylate methacrylate, 2,2-bis [4- (β-methacryloyloxyethoxy) cyclohexyl] propane, 1,3-bis (methacryloyloxymethyl) cyclohexane, 1,3-bis (methacryloyloxyethyl) Bifunctional (meth) acrylates such as oxymethyl) cyclohexane, 1,4-bis (methacryloyloxymethyl) cyclohexane, 1,4-bis (methacryloyloxyethyloxymethyl) cyclohexane, 1,3,5-tris (methacryloyloxymethyl) ) And trifunctional (meth) acrylates such as cyclohexane and 1,3,5-tris (methacryloyloxyethyloxymethyl) cyclohexane. Among these, bifunctional (meth) acrylate is preferred from the viewpoint of flexibility. Preferred, more preferred difunctional methacrylate from the viewpoint of heat resistance. Furthermore, at least one bifunctional (meth) acrylate selected from the group consisting of the following general formulas (5), (6) and (7) is preferable from the viewpoint of optical performance, and bifunctional methacrylate is particularly preferable.

Component (C) is a photopolymerization initiator such as benzophenone, benzoin methyl ether, benzoin propyl ether, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6. -Trimethylbenzoyldiphenylphosphine oxide and the like. Among these, radical cleavage type photopolymerization initiators such as 1-hydroxycyclohexyl phenyl ketone and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are preferable in terms of rapid curing. These photopolymerization initiators (C) may be used alone or in combination of two or more.
Content of a photoinitiator (C) is 0.1-5 weight part with respect to a total of 100 weight part of a component (A) and a component (B), Furthermore, 0.1-3 weight part, Especially The amount is preferably 0.3 to 2 parts by weight, particularly 0.5 to 1.5 parts by weight. When there is too much content, the retardation of a resin molding will increase and it exists in the tendency for the light transmittance in 400 nm to fall. On the other hand, if the amount is too small, the polymerization rate decreases, and the polymerization may not proceed sufficiently.

  In the present invention, a small amount of auxiliary components may be included as long as the physical properties of the resin molded body of the present invention are not impaired. For example, monomers having an ethylenically unsaturated bond other than components (A) and (B), polymerization inhibitors, thermal polymerization initiators, chain transfer agents, antioxidants, ultraviolet absorbers, antifoaming agents, leveling agents , Blueing agents, dyes and pigments, fillers and the like.

  Examples of the monomer having an ethylenically unsaturated bond other than the components (A) and (B) include, for example, methyl methacrylate, 2-hydroxyethyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl Monofunctional (meth) acrylates such as (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, di (meth) acrylate of polyethylene glycol higher than tetraethylene glycol 1,3-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 2-hydroxy-1,3-di (meth) acrylate Polyfunctional (meth) acrylates such as xylpropane, 2,2-bis [4- (meth) acryloyloxyphenyl] propane, trimethylolpropane tri (meth) acrylate, methacrylonitrile, methacrylonitrile, methacrylonitrile, etc. ) Styrenic compounds such as acrylic acid derivatives, styrene, chlorostyrene, divinylbenzene, and α-methylstyrene.

  The content of the monomer having an ethylenically unsaturated bond other than components (A) and (B) is 30 parts by weight or less with respect to a total of 100 parts by weight of component (A) and component (B), It is preferably 20 parts by weight or less, particularly 10 parts by weight or less. When there is too much content, it exists in the tendency for the heat resistance and impact resistance of a resin molding to fall.

  Known compounds can be used as the thermal polymerization initiator. For example, hydroperoxide such as hydroperoxide, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide Peroxyesters such as dialkyl peroxides such as oxides, peroxyesters such as t-butylperoxybenzoate and t-butylperoxy (2-ethylhexanoate), diacyl peroxides such as benzoyl peroxide, and diisopropylperoxycarbonates Examples thereof include peroxides such as carbonate, peroxyketal, and ketone peroxide.

  As the chain transfer agent, a polyfunctional mercaptan compound is preferable. Examples of the polyfunctional mercaptan compound include pentaerythritol tetrakisthioglycolate, pentaerythritol tetrakisthiopropionate, and the like. These polyfunctional mercaptan compounds are preferably used in a proportion of usually 10 parts by weight or less, more preferably 5 parts by weight or less, particularly 3 parts by weight with respect to 100 parts by weight of the photopolymerizable composition [I]. Part or less is preferred. When there is too much this usage-amount, there exists a tendency for the heat resistance and rigidity of the resin molding obtained to fall.

  Examples of the antioxidant include 2,6-di-t-butylphenol, 2,6-di-t-butyl-p-cresol, 2,4,6-tri-t-butylphenol, 2,6-di- t-butyl-4-s-butylphenol, 2,6-di-t-butyl-4-hydroxymethylphenol, n-octadecyl-β- (4′-hydroxy-3 ′, 5′-di-t-butylphenyl) ) Propionate, 2,6-di-tert-butyl-4- (N, N-dimethylaminomethyl) phenol, 3,5-di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 2,4 -Bis (n-octylthio) -6- (4-hydroxy-3 ', 5'-di-t-butylanilino) -1,3,5-triazine, 4,4-methylene-bis (2,6-di-) t-Butylpheno ), 1,6-hexanediol bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide 4,4′-di-thiobis (2,6-di-t-butylphenol), 4,4′-tri-thiobis (2,6-di-t-butylphenol), 2,2-thiodiethylenebis [3 -(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis- (3,5-di-tert-butyl-4-hydroxy-hydrocinnamide), N, N '-Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, calcium (3,5-di-tert-butyl-4-hydroxybenzyl) monoethylphosphone 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-t-butyl-4-hydroxy) Phenyl) isocyanurate, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris-2 [3 (3,5-di-tert-butyl-4-hydroxy) Phenyl) propionyloxy] ethyl isocyanate, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenyl) propionate] methane, 3,5-di-t-butyl-4-hydroxybenzyl Examples of the compound include phosphite-diethyl ester, and these compounds may be used alone or in combination of two or more. Among these, tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4-hydroxyphenyl) propionate] methane is particularly preferable because the effect of suppressing the hue is increased.

  The content of the antioxidant is usually preferably 0.001 to 1 part by weight, particularly preferably 0.01 to 0.5 part by weight, based on 100 parts by weight of the photopolymerizable composition [I]. is there. If the amount of such an antioxidant is too small, the light resistance of the resin molded product tends to decrease, and if it is too large, the light transmittance tends to decrease.

Thus, the photopolymerizable composition [I] used in the present invention is obtained.
Next, the manufacturing method of the resin molding of this invention using this photopolymerizable composition [I] is demonstrated.

As a manufacturing method of the resin molding in this invention, it is preferable to photocure the said photopolymerizable composition [I] with the irradiation light quantity of 1-100 J / cm < ² > or less using the ultraviolet-ray of wavelength 200-400 nm. A more preferable range of the irradiation light amount is 5 to 50 J / cm ² , and more preferably 10 to 30 J / cm ² . When the amount of irradiation light is too large, the productivity tends to decrease, and when it is too small, the polymerization tends to be insufficient.
The illuminance of ultraviolet light is preferably 10 to 5000 mW / cm ² , particularly preferably 100 to 1000 mW / cm ² . If the illuminance is too small, there is a tendency that the resin molded body is not sufficiently cured. Conversely, if the illuminance is too large, polymerization tends to run away and birefringence tends to increase.

  The ultraviolet ray source may be any one that is usually used in photopolymerization, and examples thereof include a metal halide lamp, a high-pressure mercury lamp lamp, an electrodeless mercury lamp, and an LED lamp. In order to prevent polymerization from running away due to infrared rays generated from a light source, it is also possible to use a filter that blocks infrared rays, a mirror that does not reflect infrared rays, or the like for the lamp. The resin molded body obtained in the present invention is preferably heat-treated for improving the degree of polymerization or releasing stress strain, and it is particularly preferred to heat-treat at 100 ° C. or higher.

  In general, photoforming is performed in a batch mode. That is, a mold in which two transparent glasses are opposed to each other through a spacer for controlling the thickness is produced, the photopolymerizable composition [I] is injected into the cavity, and the active energy ray is irradiated and cured. And demolding.

  Thus, the resin molded body of the present invention can be obtained. In particular, in order to obtain a resin molded body having a thickness of 0.5 mm or more and satisfying the requirements (α) and (β), the photopolymerizable property is obtained. The content ratio of the component (A) polyfunctional urethane (meth) acrylate and the component (B) polyfunctional (meth) acrylate in the composition [I] is important, and in the case of a thick resin molding, the component (A ) In a relatively large amount, the resin molded product of the present invention can be obtained efficiently.

  In addition, since the reaction rate by photopolymerization is high in the case where the thickness of the resin molded product is thin, a certain degree of surface hardness (for example, 6H to 7H) even if the content ratio of the polyfunctional urethane (meth) acrylate is small or large. In contrast, in the case of a thick resin molded body, the content ratio of the polyfunctional urethane (meth) acrylate is very important.

  And in the resin molding of this invention, although it has a self-repairing property with respect to the damage | wound produced in the resin molding as mentioned above, a self-repair is accelerated by heating or making it contact with a solvent. be able to. In the case of heating, for example, it is preferable to heat-treat the resin molded body at 50 to 300 ° C., preferably 100 to 250 ° C. in the air or under vacuum. The reason that self-healing is accelerated by heating is presumed to be because the polymer in the scratches and dents easily moves.

In the case of contact with a solvent, examples of the contact method include immersion, shower, steam and the like, but immersion is preferred from the viewpoint of simplicity of equipment. As the solvent, solvents such as water, alcohols such as methanol, ethanol and propanol, toluene, xylene, methyl ethyl ketone, methylene chloride, chloroform, DMSO and DMF are used.
In the case of immersion in a solvent, the resin molded body is preferably immersed in the solvent for several hours to several days, preferably for 1 hour to 3 days. The immersion temperature is preferably room temperature to 200 ° C, particularly 50 to 100 ° C. The reason why the self-repair is accelerated by the immersion in the solvent is presumed to be that the polymer easily moves due to the swelling of the surface layer of the scratch or the dent.

  In addition, a gas barrier film can be formed on the resin molded body of the present invention. Examples of the gas barrier film include an inorganic film such as a silicon oxide film or alumina, and an organic film made of a vinyl alcohol resin such as a polyvinyl alcohol resin or an ethylene-vinyl alcohol copolymer. As the inorganic film, a silicon oxide film having a thickness of 0.05 to 0.5 μm is preferable, and as the organic film, an ethylene-vinyl alcohol copolymer having a thickness of 0.5 to 5 μm is preferable.

  Moreover, the resin molding of this invention can form a transparent conductive film in single side | surface, and can be used as a touchscreen board | substrate. The material of the transparent electrode is not particularly limited, and examples thereof include inorganic conductive films such as ITO and IGZO, and organic conductive films such as PEDOT. The surface resistance value of the transparent conductive film is preferably 1000Ω / □ or less, more preferably 10 to 900Ω / □ or less, and still more preferably 50 to 500Ω / □ or less. If the surface resistance is too high, the conductivity tends to decrease.

  Moreover, the resin molding of this invention can form an adhesive layer in single side | surface, and can use it as a protective plate with an adhesion layer. The material of the pressure-sensitive adhesive layer is not particularly limited, and an acrylic or silicon-based pressure-sensitive adhesive is appropriately used.

  Thus, the resin molded body of the present invention can be suitably used particularly as a protective plate or a touch panel substrate.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the examples, “parts” and “%” mean weight basis.
The measuring method of each physical property is as follows.

(1) Pencil hardness It tested by load 750g according to JISK-5600-5-4. Immediately after rubbing the pencil and after rubbing, the scratches on the surface after standing at 23 ° C. and 50% RH for 3 days were visually evaluated, and the pencil hardness without scratches was measured.

(2) Haze ratio in the scratch test (β2 / β1)
In accordance with JIS K 7361, using a haze meter “NDH-4000” manufactured by Nippon Denshoku Industries Co., Ltd., a stroke width of # 0000 steel wool having a diameter of 1 cm and a weight of 160 g is applied to the surface of the resin molded body. Haze (%) (haze β1) immediately after reciprocating 5000 at 5 cm and speed of 5 cm / sec, and haze (%) (haze β2) after leaving the resin molded body at 23 ° C. and 50% RH for 3 days The haze ratio (β2 / β1) was calculated.
In addition, the steel wool used what was put together in diameter 1cm and cut so that the surface might become uniform.

(3) Scratch resistance The degree of scratching on the surface after # 500 steel wool having a diameter of 1 cm applied with a weight of 500 g was reciprocated 500 times with a stroke width of 5 cm and a speed of 5 cm / sec. It observed visually and evaluated on the following reference | standard.
○ ・ ・ ・ Scratchless △ ・ ・ ・ Several scratches × ・ ・ ・ Made cloudy due to scratches Note that the steel wool was gathered to a diameter of 1 cm and cut so that the surface was uniform. I used something.

(4) Light transmittance (%)
Total light transmittance (%) was measured using a haze meter “NDH-4000” manufactured by Nippon Denshoku Industries Co., Ltd.

(5) Haze of resin molding (%)
Based on JIS K7136, it measured using the Nippon Denshoku Industries haze meter "NDH-4000".

(6) Surface roughness Ra (nm)
According to JIS B0601: 2001, “Surfcom 570A” manufactured by Tokyo Seimitsu Co., Ltd. was used to measure the surface roughness Ra of the molded resin (cutoff: 0.8 μm, measurement length: 4 mm).

(7) Flexural modulus (GPa)
Using a test piece of length 25 (mm) × width 10 (mm), measurement was performed at 25 ° C. with an autograph AG-5kNE (distance between fulcrums 20 mm, 0.5 mm / min) manufactured by Shimadzu Corporation.

(8) Glass transition temperature (° C)
Using a test piece having a length of 20 mm and a width of 5 mm, using a tensile mode of a dynamic viscoelastic device “DVE-V4 FT Rheospectr” manufactured by Rheology, a frequency of 10 Hz, a heating rate of 3 ° C./min, a strain Measurements were taken at 0.025%. The ratio (tan δ) of the imaginary part (loss elastic modulus) to the real part (storage elastic modulus) of the obtained complex elastic modulus was determined, and the maximum peak temperature of tan δ was defined as the glass transition temperature Tg (° C.).

(9) Saturated water absorption (%)
Saturated water absorption (%) was calculated from the weight increase after immersion in water at 23 ° C. for 20 days using a 50 mm × 50 mm test piece.

(10) Surface resistance (Ω / □)
It measured using the 4-terminal method resistance measuring device (Lorester MP) made from Mitsubishi Chemical Corporation using the 100 mm square test piece.

(11) Viscosity Using an E-type viscometer manufactured by Tokyo Keiki Co., Ltd., the viscosity was measured at 25 ° C. and a rotational speed of 5 rpm (EMD 3 ° cone).

<Example 1>
[Preparation of Photopolymerizable Composition [I-1]]
35 parts of urethane acrylate having a hexafunctional alicyclic structure, 65 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.), 1- 1 part of hydroxycyclohexyl phenyl ketone (“Irgacure 184” manufactured by Ciba Specialty Chemicals) was stirred at 60 ° C. until uniform, and then filtered through a 10 μm filter to obtain a photopolymerizable composition [I-1]. .

[Preparation of molded resin]
The above photopolymerizable composition [I-1] (23 ° C.) was poured into a mold using two glass plates facing each other and a silicon plate having a thickness of 0.7 mm as a spacer, and using a metal halide lamp, Ultraviolet rays were irradiated at an illuminance of 200 mW / cm ² and a light amount of 20 J / cm ² . Thereafter, the cured product obtained by demolding was heated in a vacuum oven at 200 ° C. for 2 hours to obtain a resin molded body having a width of 50 mm × a length of 50 mm × a thickness of 0.7 mm.
The obtained resin molding had favorable characteristics as a substrate as shown in Table 2 below. In particular, it was 8H in the visual evaluation immediately after rubbing with a pencil, but it was 9H in the visual evaluation after standing at 23 ° C. and 50% RH for 3 days, and self-repairability was also confirmed. Self-healing properties were also confirmed in haze evaluation (haze ratio (β2 / β1)).

[Production of touch panel substrate]
A transparent conductive film made of ITO having a thickness of 500 mm (angstrom) was formed on one surface of the obtained resin molding by sputtering to obtain a touch panel substrate. Such a touch panel substrate had a surface resistance value of 100Ω / □, and had good characteristics as a touch panel substrate.

<Example 2>
[Preparation of Photopolymerizable Composition [I-2]]
Except for using 40 parts of urethane acrylate having a hexafunctional alicyclic structure and 60 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.) Obtained a photopolymerizable composition [I-2] in the same manner as in Example 1.

[Preparation of molded resin]
In the same manner as in Example 1, a resin molded body having a width of 50 mm, a length of 50 mm, and a thickness of 0.7 mm was obtained.
The obtained resin molding had favorable characteristics as a substrate as shown in Table 2 below. In particular, it was 8H in the visual evaluation immediately after rubbing with a pencil, but it was 9H in the visual evaluation after standing at 23 ° C. and 50% RH for 3 days, and self-repairability was also confirmed. Self-healing properties were also confirmed in haze evaluation (haze ratio (β2 / β1)).

[Accelerated test for self-healing]
The resin molded body rubbed and scratched with a 10H pencil was heated in an oven at 200 ° C. for 1 hour. The wound that was in was gone.
Further, the resin molded body rubbed with a 10H pencil and scratched was immersed in water at 23 ° C. for 3 days. The wound that was in was gone.

<Example 3>
[Preparation of Photopolymerizable Composition [I-3]]
Other than using 50 parts of urethane acrylate having a hexafunctional alicyclic structure and 50 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.) Obtained a photopolymerizable composition [I-3] in the same manner as in Example 1.

[Preparation of molded resin]
In the same manner as in Example 1, a resin molded body having a width of 50 mm, a length of 50 mm, and a thickness of 0.7 mm was obtained.
The obtained resin molding had favorable characteristics as a substrate as shown in Table 2 below. In particular, it was 9H in the visual evaluation immediately after rubbing with a pencil, but it was 10H in the visual evaluation after standing at 23 ° C. and 50% RH for 3 days, and self-repairability was also confirmed. Self-healing properties were also confirmed in haze evaluation (haze ratio (β2 / β1)).

<Example 4>
[Preparation of Photopolymerizable Composition [I-4]]
Other than using 55 parts of urethane acrylate having a hexafunctional alicyclic structure and 45 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.) Obtained a photopolymerizable composition [I-4] in the same manner as in Example 1.

[Preparation of molded resin]
In the same manner as in Example 1, a resin molded body having a width of 50 mm, a length of 50 mm, and a thickness of 0.7 mm was obtained.
The obtained resin molding had favorable characteristics as a substrate as shown in Table 2 below. In particular, it was 9H in the visual evaluation immediately after rubbing with a pencil, but it was 10H in the visual evaluation after standing at 23 ° C. and 50% RH for 3 days, and self-repairability was also confirmed. Self-healing properties were also confirmed in haze evaluation (haze ratio (β2 / β1)).

<Comparative Example 1>
Other than using 10 parts of urethane acrylate having a hexafunctional alicyclic structure and 90 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.) In the same manner as in Example 1, a photopolymerizable composition [I′-1] was obtained.

[Preparation of molded resin]
In the same manner as in Example 1, a resin molded body having a width of 50 mm, a length of 50 mm, and a thickness of 0.7 mm was obtained.
The obtained resin molded body had a surface hardness of 5H as shown in Table 2 below, and no self-healing property was confirmed.

<Comparative example 2>
Other than using 70 parts of urethane acrylate having a hexafunctional alicyclic structure and 30 parts of bis (hydroxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane dimethacrylate (“DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.) Tried to prepare the photopolymerizable composition [I′-2] in the same manner as in Example 1, but could not be filtered with a 10 μm filter because of its high viscosity.

<Comparative Example 3>
In the same manner as in Example 1, a photopolymerizable composition [I-1] was obtained.

[Preparation of molded resin]
In the same manner as in Example 1, a resin molded body having a width of 50 mm, a length of 50 mm, and a thickness of 0.2 mm was obtained.
As shown in Table 2 below, the obtained resin molded body has a surface hardness of 8H, and it is 8H in visual evaluation after being left at 23 ° C. and 50% RH for 3 days, and self-repairability is not confirmed. It was. Self-healing property was not confirmed even in evaluation by haze (haze ratio (β2 / β1)).
The evaluation results of Examples and Comparative Examples are shown in Table 2 below.

  As can be seen from the above results, in the example products, although they are thick resin molded products, the surface hardness is very excellent, and also the self-healing from the measurement result of the haze ratio (β2 / β1) It has excellent properties. On the other hand, in the comparative example 1, since there was too little polyfunctional urethane (meth) acrylate (A), it was inferior to the surface hardness and self-repairing property of a resin molding. In Comparative Example 3, the photopolymerizable composition [I] was the same as in Example 1, but it was a thin resin molded product, so that deep scratches were likely to occur in a heavy load scratch resistance test (500 g). It was also inferior to scratching and self-healing.

  The resin molded body of the present invention can be advantageously used for various optical materials and electronic materials. For example, liquid crystal substrates, organic / inorganic EL substrates, electronic paper substrates, light guide plates, phase difference plates, touch panels, etc., various display members, optical recording substrates and film / coating applications for optical disks, thin films, etc. It can be used for energy applications such as battery substrates and solar cell substrates, optical communication applications such as optical waveguides, and various optical films, sheets and coatings such as functional films and sheets, antireflection films and optical multilayer films. In particular, it is highly expected as a capacitive touch panel substrate.

Claims (16)

In a transparent resin molded product having a thickness of 0.5 mm or more obtained by photocuring the photopolymerizable composition [I], the resin molded product satisfying the following requirements (α) and (β): .
(Α) The pencil hardness of the resin molded body surface is 8H or more.
(Β) In a test in which a load of 160 g is applied to # 0000 steel wool having a diameter of 1 cm and reciprocated 5000 times at a stroke width of 5 cm and a speed of 5 cm / second, the haze immediately after the test is β1 (%). The haze ratio (β2 / β1) is 0.9 or less when the haze after leaving for 3 days at 23 ° C. and 50% RH is β2 (%). The photopolymerizable composition [I] contains the following components (A), (B), and (C), and the content ratio (A: B) of the components (A) and (B) is 30: 70-60: 40 (weight ratio), The resin molding of Claim 1 characterized by the above-mentioned.
(A) Polyfunctional urethane (meth) acrylate having an alicyclic structure (B) Polyfunctional (meth) acrylate having an alicyclic structure (excluding (A) above)
(C) Photopolymerization initiator   The resin molded product according to claim 2, wherein the polyfunctional urethane (meth) acrylate (A) having an alicyclic structure is tetrafunctional or higher. The polyfunctional urethane (meth) acrylate (A) having an alicyclic structure has an alicyclic structure represented by the following formula (1), (2), (3) or (4). Or the resin molding of 3.

  The polyfunctional (meth) acrylate (B) having an alicyclic structure (excluding the component (A)) has two (meth) acryloyl groups in the molecule. The resin molding as described in any one of these. The polyfunctional (meth) acrylate (B) having an alicyclic structure (excluding the component (A)) is at least one selected from the group consisting of the following general formulas (5), (6) and (7) It is the above bifunctional (meth) acrylate, The resin molding as described in any one of Claims 2-5 characterized by the above-mentioned.

  Light transmittance is 85% or more, The resin molding as described in any one of Claims 1-6 characterized by the above-mentioned.   Haze is 1% or less, The resin molding as described in any one of Claims 1-7 characterized by the above-mentioned.   The resin molded body according to claim 1, wherein at least one surface has a surface roughness Ra of 20 nm or less.   The resin molded article according to any one of claims 1 to 9, wherein a flexural modulus is 3 GPa or more.   Glass transition temperature is 200 degreeC or more, The resin molded object as described in any one of Claims 1-10 characterized by the above-mentioned.   The resin molded body according to any one of claims 1 to 11, wherein the saturated water absorption is 0.5 to 2%.   A protective plate for a display comprising the resin molded body according to any one of claims 1 to 12.   A touch panel substrate, wherein a transparent conductive film is formed on one surface of the resin molded body according to any one of claims 1 to 12.   A method for self-repairing a resin molded body, comprising repairing a scratch produced in the resin molded body according to any one of claims 1 to 12 by subjecting the resin molded body to heat treatment at 50 to 250 ° C. .   A method for self-repairing a resin molded body, comprising repairing a scratch produced in the resin molded body according to any one of claims 1 to 12 by bringing the resin molded body into contact with a solvent.