JP4735003B2 - Transparent resin molding and coating film - Google Patents

Description

  The present invention is a transparent resin molded body having a hard coat coating formed on a transparent resin base material, particularly excellent in wear resistance and surface hardness. The present invention relates to a transparent resin molded product having resistance to dirt and print decoration.

  Transparent materials of various plastics are portable devices, household electrical appliances, industrial electronic devices, automotive electronic devices, etc., from the viewpoints of lightness, transparency, processability, and resistance to cracking and safety. Is used as a protective cover for information display parts such as monitors. However, these plastic materials are inferior to glass in terms of wear resistance and scratch resistance and have a drawback of being easily damaged.

  In order to eliminate this drawback, various studies on surface modification have been made. For example, it is widely practiced to coat the surface of a substrate with a thermosetting resin such as polyorganosiloxane or melamine, or an ultraviolet curable resin. In these coatings, a fluorine-based or modified silicone-based surface conditioner is usually added to the cured resin in order to spread the coating film uniformly on the substrate surface. Applied to a good appearance.

  Thus, the hard coat coating film obtained using the fluorine-based or silicone-based surface conditioner has water repellency and easily repels highly polar stains, but on the contrary, it becomes highly lipophilic. In this state, when practical dirt such as sebum comes into contact, the oil-containing dirt is held in a fine spherical shape on the surface, and at first glance, it seems that the dirt does not easily adhere, but it is held in a fine spherical shape. If you try to wipe off the soil containing these oils because it is a cloth, the soil spreads thinly and becomes an oil film, which deteriorates the appearance of the transparent material on which the hard coat film is formed, or functions such as visibility. It will be damaged. Further, there has been a problem that practical pollutants such as cosmetics penetrate into the inside and cannot be easily removed by cleaning from the surface such as wiping.

Therefore, in order to prevent sebum and the like from adhering to the hard coat coating film, a hard coat layer containing a fluorosurfactant is formed (JP-A-11-293159), or fluorine atoms, silicon atoms and active energy rays. Proposals have been made to cure a compound having a polymerizable group to form a hard coat layer (Japanese Patent Laid-Open No. 2003-335984). However, in these methods of further improving the water repellency of the hard coat surface to prevent the adhesion of fats, sebum and cosmetic stains are less likely to adhere. If you try to decorate by printing, etc., the printing ink will be repelled, so you can not decorate by general-purpose printing methods such as screen printing and gravure printing. Another problem arises in that applications are significantly restricted in practical use in exterior parts of electrical products, industrial electronic equipment, automotive electronic equipment, etc., especially protective covers for information display parts such as monitors.
JP-A-11-293159 JP 2003-335984 A

  The present invention solves the above-mentioned problems, has excellent surface hardness, scratch resistance, and abrasion resistance, is difficult to adhere to practical stains such as sebum and cosmetics, and is well decorated for printing. An object of the present invention is to provide a transparent resin molded article on which a hard coat coating film that can be formed is formed.

  The present inventors formed a coating film having a specific surface energy on a transparent resin base material, which is composed of a polyfunctional oligomer and a polyfunctional and / or monofunctional monomer and having a specific number of functional groups. As a result, the inventors have found that the above-described problems can be solved, and have completed the present invention.

  That is, in the present invention, a coating film made of an ultraviolet curable resin having an average functional group number of 3.4 or more, which is composed of a polyfunctional oligomer and a polyfunctional monomer and / or a monofunctional monomer, is formed on a transparent resin substrate. A gist is a transparent resin molded body, characterized in that the surface energy of the coating film is 32 to 40 mN / m.

  As described above, the transparent resin molded body obtained by forming a coating film of an ultraviolet curable resin comprising a specific resin composition on the surface of a transparent resin substrate and setting the surface energy of the coating film to a specific range is excellent. In addition, while maintaining surface hardness, scratch resistance, and abrasion resistance, practical stains such as sebum and cosmetics are difficult to adhere, and printing decoration can be performed well.

  As the transparent resin base material of the present invention, general transparent plastics can be used, but exterior parts such as portable devices, household electrical appliances, industrial electronic devices, and automotive electronic devices, which are assumed as applications of the present invention. In particular, as a protective cover for an information display section such as a monitor, it is most preferable to use a polycarbonate resin as a base material from the viewpoint of lightness, transparency, workability, and resistance to cracking and safety. Other common transparent resins such as polymethyl methacrylate, polyethylene terephthalate, and polyvinyl chloride can also be suitably used.

<Polyfunctional oligomer>
As the polyfunctional oligomer used in the present invention, urethane acrylate oligomer, epoxy acrylate, polyester acrylate, or the like can be used.

  The epoxy acrylate oligomer can be obtained, for example, by an esterification reaction between an oxirane ring of a low molecular weight bisphenol type epoxy resin or a novolak epoxy resin and acrylic acid. Moreover, as a polyester acrylate oligomer, it is obtained by esterifying the hydroxyl group of the polyester oligomer which has a hydroxyl group in the both ends obtained by condensation of polyhydric carboxylic acid and a polyhydric alcohol with acrylic acid, for example. Alternatively, it can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a polyvalent carboxylic acid with acrylic acid.

  The polyfunctional oligomer of the present invention is most preferably a urethane acrylate oligomer. This is because, together with the hardness required for a hard coat, more excellent wear resistance and scratch resistance can be obtained. The urethane acrylate oligomer is a reaction product of an isocyanate compound obtained by reacting a polyol with diisocyanate and an acrylate monomer having a hydroxyl group, and examples of the polyol include polyester polyol, polyether polyol, and polycarbonate diol.

  Among urethane acrylate oligomers, it is very preferable to use those having 6 or more functional groups. This is because the use of a hexa-functional urethane acrylate achieves a high degree of cross-linking while achieving performance as a hard coat film such as hardness and wear resistance, and other cure shrinkage that occurs during high cross-linking. This is because there are relatively few polyfunctional oligomers.

  The manufacturing method of the polyester polyol used for preparation of a urethane acrylate oligomer is not specifically limited, A well-known manufacturing method can be employ | adopted. For example, the diol and dicarboxylic acid or dicarboxylic acid chloride may be subjected to a polycondensation reaction, or the diol or dicarboxylic acid may be esterified and subjected to an ester exchange reaction. Examples of the dicarboxylic acid include adipic acid, succinic acid, glutaric acid, pimelic acid, sebacic acid, azelaic acid, maleic acid, terephthalic acid, isophthalic acid, and phthalic acid. Examples of the diol include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol, and tetrapropylene glycol.

  The polyether polyol is preferably a polyethylene oxide, polypropylene oxide, ethylene oxide-propylene oxide random copolymer having a number average molecular weight of less than 600. If it is 600 or more, the cured product may be too soft and hard coat performance may not be obtained.

  Examples of the polycarbonate diol include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 2-ethyl-1,3-hexanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, polyoxyethylene glycol, and the like are used, and one kind or two kinds You may use the above together.

  As the diisocyanate, a linear or cyclic aliphatic diisocyanate is used. Of course, aromatic diisocyanates can also be used, and it is possible to easily obtain excellent hard coat properties such as hardness and scratch resistance. On the other hand, polyfunctional oligomers are the main components that form the hard coat skeleton. This is because when the component is used, the light resistance is lowered, and yellowing easily occurs upon exposure to light, so that the function as a transparent hard coat is impaired in practical use. Representative examples of the linear or cyclic aliphatic diisocyanate include hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated xylylene diisocyanate.

  Examples of acrylate monomers having a hydroxyl group include trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, Examples include polyethylene glycol monoacrylate.

<Multifunctional monomer>
Examples of the polyfunctional acrylate monomer that can be used in the present invention include dipentaerythritol hexaacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, ethoxylated trimethylol. Examples thereof include propane triacrylate, ethoxylated pentaerythritol triacrylate, ethoxylated pentaerythritol tetraacrylate, and polyethylene glycol diacrylate.

  Of these polyfunctional monomers, it is preferable to use a bifunctional acrylate having a cyclic structure. This is because excellent adhesion to a substrate can be obtained while maintaining excellent hard coat performance such as hardness, abrasion resistance, and scratch resistance. Examples of the bifunctional acrylate having this cyclic structure include ethoxylated bisphenol A diacrylate, ethoxylated hydrogenated bisphenol A diacrylate, ethoxylated cyclohesane dimethanol diacrylate, and tricyclodecane dimethanol diacrylate.

<Monofunctional monomer>
Monofunctional monomers include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, polyethylene glycol monoacrylate, acryloyl morpholine, N vinyl pyrrolidone, N vinyl formamide, isobornyl An acrylate etc. are mentioned.

  The ultraviolet curable resin of this invention consists of the said polyfunctional oligomer, a polyfunctional, and / or a monofunctional monomer, and it is necessary for an average functional group number to be 3.4 or more. When the average number of functional groups is less than 3.4, not only excellent hardness as a hard coat is obtained, but also practical contaminants such as sebum and cosmetics penetrate into the inside, and these are removed by cleaning from the surface such as wiping. There arises a problem that it cannot be easily dropped.

  The transparent resin molding of the present invention is obtained by applying the resin component to a transparent resin substrate and forming a coating film by irradiating with ultraviolet rays. At this time, a photopolymerization initiator, an organic solvent are added to the resin component. Diluted liquid or the like is added.

  The photopolymerization initiator has a function as a polymerization initiator when the photopolymerizable compound is cured by ultraviolet rays, and a known one can be used alone or in combination, such as benzoin, benzoin methyl ether, Benzoin or benzoin alkyl ethers such as benzoin ethyl ether and benzoin isopropyl ether, aromatic ketones such as benzophenone and benzoylbenzoic acid, alpha-dicarbonyls such as benzyl, benzyl ketals such as benzyldimethyl ketal and benzyl diethyl ketal, Acetophenone, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one , 1- Acetophenones such as 4-isopropylphenyl) -2-hydroxy-2-methyl-propan-1-one, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanone-1, 2-methyl Anthraquinones such as anthraquinone, 2-ethylanthraquinone and 2-t-butylanthraquinone, thioxanthones such as 2,4-dimethylthioxanthone, 2-isopropylthioxanthone and 2,4-diisopropylthioxanthone, bis (2,4,6-trimethyl) Phosphine oxides such as benzoyl) -phenylphosphine oxide, alpha-acyloximes such as 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, ethyl p-dimethylaminobenzoate, p-Dimethylaminobenzoic acid It can be used amines such as isoamyl.

  Further, in order to obtain a coating film having an excellent appearance, a fluorine-based or modified silicone-based surface conditioner is added to the paint. As the surface conditioner of fluorine type or modified silicone type, polyether type, alkyl type and polyester type can be used, but polyether type is particularly preferable. Moreover, it is also possible to use these in combination.

  The resin component is applied to the substrate after being diluted and dissolved with an organic solvent as necessary to obtain a coating liquid. Commercially available organic solvents can be used, such as aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, propanol and butanol, methyl ethyl ketone, 2 -Use of ketones such as pentanone and isophorone, esters such as ethyl acetate, butyl acetate and methoxypropyl acetate, cellosolve solvents such as ethyl cellosolve, and glycol solvents such as methoxypropanol, ethoxypropanol and methoxybutanol alone or in combination it can. The viscosity and resin concentration of the coating liquid can be appropriately selected according to the situation, purpose, and application method.

  The transparent resin molded product of the present invention can be obtained by the steps of mixing, diluting, applying to a transparent resin substrate, drying, and curing the resin components. Application to the resin substrate can be performed on one or both surfaces of the resin substrate using a known method such as a roll coater, a flow coater, a spray coater, a curtain flow coater, a dip coater, or a slit die coater. A simultaneous or sequential method can be used as the coating method on both sides.

  The thickness of the coating film is not particularly limited, but about 1 μm or more is necessary to obtain practical performance as a hard coat. In addition, when the film thickness is extremely thick, for example, 50 μm or more, it is difficult to uniformly cure to the inside by ultraviolet rays, and problems such as adhesion occur, and defects such as cracks due to curing shrinkage of the coating film are also observed. Therefore, it is considered desirable that the thickness is less than 50 μm.

  After coating on the transparent resin substrate as described above, the temperature of the substrate and the atmosphere is raised, and after sufficiently diluting the diluting solvent, ultraviolet rays are irradiated to cure the coating film. For the ultraviolet irradiation, a general electroded or electrodeless high-pressure mercury lamp or metal halide lamp can be used. Of course, a low voltage electron beam irradiation apparatus of about 100 keV can also be used. When an electron beam is used as the curing means, a polymerization initiator as exemplified above is not necessary.

  The surface energy of the coating film thus obtained needs to be in the range of 32 to 40 mN / m. When the surface energy is less than 32 mN / m, it has water repellency and easily repels highly polar dirt, but on the contrary, it becomes highly oleophilic, and when it comes into contact with practical dirt such as sebum, oil-containing dirt It is held in a fine spherical shape on the surface, and since it is a cloth, when it is wiped off, the dirt spreads thinly and becomes an oil film, which deteriorates the appearance of the transparent base material on which the hard coat film is formed or impairs functions such as visibility. . In addition, if the decoration by printing is performed, the printing ink is repelled, so that decoration by a general-purpose printing method such as screen printing or gravure printing cannot be performed.

  On the other hand, when the surface energy exceeds 40 mN / m, the surface energy of practical soil components such as sebum becomes relatively low energy, and conversely, the ease of wetting and spreading increases, so that it is easily soiled and wiped off. It becomes difficult. In addition, it is widely used industrially to increase the hydrophilicity by intentionally increasing the surface energy, for example, a high energy surface of 70 mN / m or more, and washing away dirt with water. In the exterior parts of portable equipment, household electrical appliances, industrial electronic equipment, automotive electronic equipment, etc., especially protective covers for information display parts such as monitors, etc. Is not general and practical.

  The method for bringing the surface energy of the coating film into the above range is not particularly limited, but can be achieved by, for example, the following method.

  The first is a method using an ultraviolet curable resin containing a proper amount of a polar group such as an ethoxy group as a polyfunctional oligomer. As this polyfunctional oligomer, a urethane acrylate oligomer is particularly preferred. This oligomer is a reaction product of an isocyanate compound obtained by reacting a polyol and a diisocyanate and an acrylate monomer having a hydroxyl group. Of the ether polyols, the intended polyfunctional oligomer can be obtained by using one having a number average molecular weight of 200 to 600. If the molecular weight exceeds 600, the cured product may be too flexible to obtain a performance as a hard coat, and if it is less than 200, the surface energy cannot be within an appropriate range.

  What is mentioned as the second means is that the ultraviolet curable resin has a polar group and has a surface energy of 30 mN / in a range that does not inhibit the formation of the coating film of the resin and does not deteriorate the appearance and performance of the coating film. This is a method of adding a relatively low molecular weight organic compound having a molecular weight of about 200 to 1500 at m or more. By continuously presenting such a compound having a polar group near the surface of the coating film, the surface energy value of the coating film can be set within a predetermined range. Although this organic compound is gradually lost from the surface in practical use, the remaining compound dispersed inside gradually moves to the surface, so that the effect can be maintained for a relatively long period of time. In this case, since the sustainability and the degree of effect depend on the structure of the organic compound and the amount added, it can be freely adjusted to some extent. If the molecular weight of the organic compound is less than 200, the molecule is too small, so that the migration to the surface is too large, and the effect is lost in a short period of time, or a problem is likely to occur during curing. When the molecular weight is 1500 or more, the transferability becomes too low, and the transfer to the surface is not made in time, and the sustainability of the effect tends to be problematic.

  The organic compound is not particularly limited and may be a commercially available general-purpose substance, but is sufficiently dispersed in a solution state with respect to the mixture of the polyfunctional oligomer of the present invention and the polyfunctional and / or monofunctional monomer. However, it does not evaporate during drying, remains in the cured coating film, and has a certain degree of surface migration. In addition, these compounds may or may not have a functional group that binds to the resin during UV curing, but if they have a functional group that binds, they migrate to the surface at the time of curing. Need to be.

  Examples of the organic compound include those having a bonding group with a cured resin, such as hydrophilic monomers such as methoxypolyethylene glycol monoacrylate, phenoxypolyethylene glycol monoacrylate, acryloylmorpholine, N vinylformamide, N vinylpyrrolidone, and polyether-modified Polydimethylsiloxane acrylate and the like, and those having no bonding group include polyether-modified polydimethylsiloxane, sorbitan fatty acid ester, fatty acid diethanolamide, polyoxyethylene alkyl ether, polyoxyethylene cholesteryl ether, polyoxyethylene phenyl ether, Polyoxyethylene fatty acid ester, polyoxyethylene, polyoxypropylene block polymer, polyoxyethylene cured castor , Polyoxyethylene alkyl amide, perfluoroalkyl alkyl ethylene oxide adducts, and the like.

  What is mentioned as the third means is that the number average molecular weight is about 10,000 to 50,000 in the range that does not inhibit the formation of the coating film of this resin and does not deteriorate the appearance and performance of the coating film. The addition of a polar polymer. According to this method, since the polymer is added, there is little adverse effect on the hard coat performance by the ultraviolet curable resin, the surface energy is increased by the presence of the polymer having a polar group, and the surface energy within a predetermined range can be obtained. Is possible. Examples of these polymers include cellulose acetate propionate, cellulose acetate butyrate, hydroxypropyl cellulose, methyl hydroxyethyl cellulose, polyvinyl pyrrolidone, and ethylene vinyl alcohol.

  As a fourth means, after the ultraviolet curable resin is cured, the obtained coating film is subjected to physicochemical treatment. That is, it is a method of adjusting the surface energy value by generating polar groups only on the very surface of the coating film by ultraviolet irradiation, corona discharge, plasma discharge or the like. The surface energy by this physicochemical treatment is high immediately after the treatment and tends to decrease with time. Therefore, the surface energy immediately after the treatment is set to about 40 to 50 mN / m, and the product is actually used. It is important to make the surface energy value within a predetermined range at the time. A commercially available apparatus may be used. In the batch type processing, there are problems such as an increase in size of the apparatus for dealing with a large area and uniformity of processing, and therefore a line type apparatus with a conveyor is more preferable. In this case, processing is possible by placing a base material coated with UV curable resin on the surface and placing it on a conveyor, and passing it through UV light, corona discharge, or plasma atmosphere at a speed that provides the specified surface energy. It is.

The first to fourth means exemplified above may be used alone or in combination.

The following were prepared from commercially available raw materials.
<Polyfunctional oligomer>
(I) Aliphatic hexafunctional urethane acrylate (trade name: EB1290, manufactured by Daicel UCB)
(II) Bifunctional bisphenol A epoxy acrylate (trade name EB3700, manufactured by Daicel UCB)
<Multifunctional monomer>
(I) Tetrafunctional pentaerythritol hexaacrylate (trade name: PETA-K, manufactured by Daicel UCB)
(II) Bifunctional ethoxylated bisphenol A diacrylate (trade name: A-BPE-4 manufactured by Shin-Nakamura Chemical Co., Ltd.)
(III) Bifunctional nonanediol diacrylate (trade name: A-NOD, manufactured by Shin-Nakamura Chemical Co., Ltd.)
<Monofunctional monomer>
N vinylformamide (trade name: Beam Set 770 Arakawa Chemical Co., Ltd.)
<Modified silicone surface conditioner>
Polyether-modified dimethylsiloxane (trade name: BYK307, manufactured by Big Chemie)

<Preparation of polyfunctional oligomer (III)>
A 1 liter four-necked flask equipped with a thermometer, stirrer, inert gas inlet, air inlet and reflux condenser is charged with 150 parts of tolylene diisocyanate (TDI) and 350 parts of polyoxyethylene diol having an average molecular weight of 400. The mixture was reacted at 80 ° C. for 5 hours under a nitrogen atmosphere. Thereafter, the mixture was cooled to 40 ° C., and then 150 parts of 2-hydroxyethyl acrylate was added and reacted at 80 ° C. for 4 hours in an air atmosphere to obtain a bifunctional urethane acrylate oligomer.

<Examples 1-2 and Comparative Examples 1-2>
As shown in Tables 1 and 2, polyfunctional oligomers and the like were blended and diluted with a 50:50 mixed dilution solvent of isopropyl alcohol and butyl acetate so that the concentration of the nonvolatile content was 20% by weight in the solution. In this case, a photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals) previously dissolved in isopropyl alcohol is diluted with one of the diluent solvents so that the nonvolatile content ratio is 5% by weight. As part. Furthermore, 0.01% by weight of a silicone-based surface conditioner was added to the nonvolatile content. The composition was sufficiently stirred and mixed, and then stored in a sealed container.

A polycarbonate sheet having a thickness of 1.5 mm was prepared as a transparent resin base material ("Polyca Ace" manufactured by Chuchu Plastic Industry Co., Ltd.), and the composition was applied using a metal bar coater so that the dry film thickness was 10 μm. . Next, the coated polycarbonate sheet was put into a hot air circulation oven at 60 ° C. and dried. After drying for 10 minutes, using a 160 W / cm metal halide lamp (manufactured by Ushio Inc.), the coated and dried polycarbonate sheet is irradiated with ultraviolet rays on a conveyor at a distance of 15 cm and a speed of 1.5 m / min to cure the composition. I let you. The transparent resin molded body on which the hard coat coating film thus obtained was formed was subjected to the following evaluation, and the results are shown in Table 1.
<Surface energy>
According to JISK6768, the surface energy of the coating film is measured using a commercially available reagent for measuring surface energy (trade name: Wetting Test Reagent, manufactured by Wako Pure Chemical Industries, Ltd.).
<Dust resistance I>
Use a magic pen (trade name: manufactured by McKee Zebra Co., Ltd.) as a hard-to-use stain for cosmetics, etc., and draw a circle with a diameter of about 2 cm on the surface of the paint film. The traces in which the magic ink was repelled and remained in a broken line shape were wiped off with a tissue paper containing isopropanol, and the appearance was visually observed and evaluated as follows.
○: A circle or broken line drawn with a magic pen can be easily wiped off and the original appearance can be restored / practically excellent △: A circle or broken line drawn with a magic pen The remaining traces cannot be easily wiped off, and the traces remain slightly / practical problems ×: The traces left as circles and broken lines drawn with a magic pen are hardly wiped off. Traces left / practical inferior <Soil resistance II>
To evaluate the adhesion and wiping properties of oil stains such as sebum in actual use, dip a cotton swab in edible olive oil, spread it thinly about 1 cm in diameter on the surface, wipe it off with dry gauze after 30 seconds, and wipe it off The sample surface was visually observed and evaluated as follows.
○: No oil film on the surface after wiping 3 reciprocations, completely wiped off / practical excellent △: Oil film remaining on the surface slightly after wiping 3 reps / practical problems ×: After 3 reciprocations of wiping, Oil is spread on the surface to form a complete oil film / practically inferior <printability>
Using a commercially available two-component ink (trade name: HAC, manufactured by Seiko Advance Co., Ltd.), 2 cm x 5 cm was printed on the surface of the coating film by screen printing using a T-270 screen mesh, and hot air at 80 ° C. After drying in a circulating oven for 30 minutes, the 25th cross-cut tape method (based on JIS K5400) was performed and evaluated as follows.
○: The print is in close contact with the first grid without peeling, and after that, even if rubbed with a nail, no peeling occurs / printing is practically possible. Even if it peels off with a nail after that, the printability is practically inferior <Pencil hardness>
According to ASTM D3363, the hardness was determined by performing a test using pencils of various hardness (trade name: Uni Mitsubishi Pencil Co., Ltd.).
<Abrasion resistance>
In accordance with ASTM D1044, a Taber abrasion test (CS10F wear wheel, load 500 g, 100 revolutions) was performed, and the following evaluation was performed based on the generated haze.
○: Haze increment is less than 10% / practically excellent Δ: Haze increment is not less than 10% and less than 15% / practical enough, but usage is limited ×: Haze increment is more than 15% / practically inferior <Abrasion resistance>
Steel wool # 000 was attached to a holder having a diameter of 30 mm, and after 100 reciprocations at a constant load of 500 g, the presence or absence of scratches on the sample surface was visually observed and evaluated as follows.
○: Not scratched at all / excellent in practical use △: Several scratches / practical enough, but limited in use ×: Scratches occurred / practically inferior

<Examples 3 to 4>
Cellulose acetate propionate (trade name: CAP504, manufactured by Eastman) containing polyfunctional oligomers and polyfunctional monomers as shown in Table 1, and having a molecular weight of 10,000 and containing an average of 4 hydroxyl groups in one molecule A transparent resin molded body on which a hard coat coating film was formed was obtained in the same manner as in Example 1 except that 5 wt% was added to the nonvolatile content, and the same evaluation was performed. The results are shown in Table 1.
<Example 5>
As shown in Table 1, a polyfunctional oligomer and a polyfunctional monomer were blended, and a transparent resin molded body on which a hard coat coating film was formed was obtained in the same manner as in Example 1. This coating film was subjected to corona discharge treatment, and the surface energy value immediately after the treatment was 48 mN / m. Thereafter, the sample was left in the room for one month, and the surface energy value was measured again after being left to be 35 mN / m. Furthermore, when it measured after three-month progress, it was 34 mN / m and it became a stable state. This molded body was evaluated in the same manner as in Example 1, and the results are shown in Table 1.
<Comparative Example 3>
As shown in Table 2, a polyfunctional oligomer and a polyfunctional monomer were blended, and a transparent resin molded product was obtained in the same manner as in Example 1. The same evaluation was performed, and the results are shown in Table 1.

<Examples 6 to 7>
Example 1 except that polyfunctional oligomers are blended as shown in Table 1 and polyethylene glycol having a number average molecular weight of 600 (trade name: polyethylene glycol 600, manufactured by Kanto Chemical Co., Inc.) is added in an amount of 1% by weight based on the nonvolatile content. A transparent resin molded product was obtained in the same manner as in Example 1, and the same evaluation was performed.
<Comparative Examples 4-5>
A transparent resin molded product was obtained in the same manner as in Example 6 or Example 7 (without adding polyethylene glycol).

  As can be seen in Tables 1 and 2, in Example 1 and Example 2 in which the surface energy was adjusted by the first method described above, it has an excellent appearance and is an excellent result in evaluation of resistance to dirt. In addition, it was excellent in printability, hardness, abrasion resistance, and scratch resistance. In contrast, in Comparative Example 1 and Comparative Example 2 in which the surface energy is within the technical range but the average number of functional groups is outside the technical range of the present invention, the stain due to the magic ink is difficult to be removed, and the wear resistance and scratch resistance are also reduced. It turns out that it is inferior.

  In Example 3 or Example 4, by adding cellulose propionate, which is a polar polymer, and in Example 5, by applying corona discharge, the surface energy of the coating is within the technical scope of the present invention. It had an excellent appearance, an excellent result in evaluation of resistance to dirt, and excellent printability, hardness, abrasion resistance, and scratch resistance. On the other hand, the composition is the same as in Example 5, but the surface energy value of the coating film is not controlled at all, and in Comparative Example 3 where the value is not within the technical range, dirt due to oil is difficult to remove, Poor printability.

  In Example 6 or Example 7 to which polyethylene glycol, which is a relatively low molecular weight organic compound having a polar group, was added, it had an excellent appearance, was excellent in evaluation of stain resistance, and printed. It was also excellent in properties, hardness, abrasion resistance, and scratch resistance. On the other hand, in Comparative Example 4 or Comparative Example 5 in which polyethylene glycol is not added, the surface energy value of the coating film is not within the technical scope of the present invention, and it is difficult to remove dirt due to oil, and there is a problem in printability. I know that there is.

Claims (8)

A transparent resin molded article in which a coating film made of an ultraviolet curable resin having an average functional group number of 3.4 or more and formed of a polyfunctional oligomer and a polyfunctional monomer and / or a monofunctional monomer is formed on a transparent resin substrate. And
The ultraviolet curable resin contains an organic compound having a polar group and a surface energy of 30 mN / m or more and a molecular weight of 200 to 1500, and an organic compound having the polar group and a surface energy of 30 mN / m or more and a molecular weight of 200 to 1500. The compound is methoxypolyethylene glycol monoacrylate, phenoxypolyethylene glycol monoacrylate, acryloylmorpholine, N vinylformamide, N vinylpyrrolidone, polyether modified polydimethylsiloxane acrylate, polyether modified polydimethylsiloxane, sorbitan fatty acid ester, fatty acid diethanolamide, Polyoxyethylene alkyl ether, polyoxyethylene cholesteryl ether, polyoxyethylene phenyl ether, polyoxyethylene fatty acid ester, polyoxy Styrene, polyoxypropylene block polymers, polyoxyethylene hardened castor oil, polyoxyethylene alkyl amide, those selected from perfluoroalkyl alkyl ethylene oxide adducts, the surface energy of the coating film, the 32~40mN / m A transparent resin molding characterized by being adjusted. A transparent resin molded article in which a coating film made of an ultraviolet curable resin having an average functional group number of 3.4 or more and formed of a polyfunctional oligomer and a polyfunctional monomer and / or a monofunctional monomer is formed on a transparent resin substrate. And
The ultraviolet curable resin contains a polar polymer having a number average molecular weight of 10,000 to 50,000, and the polar polymer having a number average molecular weight of 10,000 to 50,000 is cellulose acetate propionate, cellulose acetate butyrate, hydroxypropyl A transparent resin molded product, wherein the surface energy of the coating film, which is selected from cellulose, methylhydroxyethylcellulose, polyvinylpyrrolidone, and ethylene vinyl alcohol, is adjusted to 32 to 40 mN / m. A transparent resin molded article in which a coating film made of an ultraviolet curable resin having an average functional group number of 3.4 or more and formed of a polyfunctional oligomer and a polyfunctional monomer and / or a monofunctional monomer is formed on a transparent resin substrate. And
After the ultraviolet curable resin is cured, the surface energy of the coating film is adjusted to 32 to 40 mN / m by performing ultraviolet irradiation, corona discharge, or plasma discharge treatment on the obtained coating film. A transparent resin molded product characterized by that. A transparent resin molded article in which a coating film made of an ultraviolet curable resin having an average functional group number of 3.4 or more and formed of a polyfunctional oligomer and a polyfunctional monomer and / or a monofunctional monomer is formed on a transparent resin substrate. And
As the polyfunctional oligomer, a bifunctional urethane acrylate oligomer that is a reaction product of an isocyanate compound obtained by reacting a polyether polyol having a number average molecular weight of 200 to 600 with a diisocyanate and an acrylate monomer having a hydroxyl group is contained. and, wherein the surface energy has a polar group ultraviolet curing resin contains a polar polymer organic compound having a molecular weight of 200 to 1500 and / or a number average molecular weight from 10,000 to 50,000 at 30 mN / m or more, the polar groups An organic compound having a surface energy of 30 mN / m or more and a molecular weight of 200 to 1500 is methoxypolyethylene glycol monoacrylate, phenoxypolyethylene glycol monoacrylate, acryloylmorpholine, N-vinylformamide, N-vinylpyrrolidone, polyester Tellurium modified polydimethylsiloxane acrylate, polyether modified polydimethylsiloxane, sorbitan fatty acid ester, fatty acid diethanolamide, polyoxyethylene alkyl ether, polyoxyethylene cholesteryl ether, polyoxyethylene phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene, The surface energy of the coating film, which is selected from polyoxypropylene block polymer, polyoxyethylene hydrogenated castor oil, polyoxyethylene alkylamide, and perfluoroalkylalkylethylene oxide adduct, is adjusted to 32 to 40 mN / m. A transparent resin molded product characterized by that. A transparent resin molded article in which a coating film made of an ultraviolet curable resin having an average functional group number of 3.4 or more and formed of a polyfunctional oligomer and a polyfunctional monomer and / or a monofunctional monomer is formed on a transparent resin substrate. And
As the polyfunctional oligomer, a bifunctional urethane acrylate oligomer that is a reaction product of an isocyanate compound obtained by reacting a polyether polyol having a number average molecular weight of 200 to 600 with a diisocyanate and an acrylate monomer having a hydroxyl group is contained. And the ultraviolet curable resin contains a polar group having a surface energy of 30 mN / m or more and a molecular weight of 200 to 1500 and / or a polar polymer having a number average molecular weight of 10,000 to 50,000, and the number average polar polymer having a molecular weight of 10,000 to 50,000, are those selected cellulose acetate propionate, cellulose acetate butyrate, hydroxypropyl cellulose, methyl hydroxyethyl cellulose, polyvinyl pyrrolidone, and ethylene vinyl alcohol, the table of the coating film Energy, transparent resin molding, characterized in that it is adjusted to 32~40mN / m. The transparent resin molded product according to any one of claims 1 to 5 , wherein at least one of the polyfunctional oligomers is a hexafunctional or higher urethane acrylate. The transparent resin molded product according to any one of claims 1 to 6 , wherein at least one of the polyfunctional monomers is a bifunctional acrylate having a cyclic structure. Consisting cured product of claim 1-7 or 1 UV-curable formed in the transparent resin molded article described in Section resin, surface energy, characterized in that it is adjusted to 32~40mN / m Coating film.