JP2021066874A - Photocurable resin composition and hard coat film - Google Patents

Abstract

To provide a photocurable resin composition that is high in wear resistance and rupture elongation and excellent in moldability and also has excellent chemical resistance, the photocurable resin composition suitable for three-dimensional molding, and a hard coat film for molding that is coated with the same.SOLUTION: A photocurable resin composition contains: urethane acrylate that is prepared by causing ethylene glycol to react with isophorone diisocyanate to yield diisocyanate, which is caused to further react with pentaerythritol triacrylate; a surface-conditioning agent; and a photopolymerization initiator. The content of the surface-conditioning agent is 0.3-3.0 wt.% relative to the total solid content.SELECTED DRAWING: None

Description

The present invention relates to a photocurable resin composition and a hard coat film having a resin cured layer thereof.

Acrylic photocurable resins are used in many fields to impart special performance to the surface of plastic films and plastic molded products. For example, they are applied on PET (polyethylene terephthalate) films to impart high hardness. The hard coat film is used in large quantities as a touch panel film and a molding film.

Among these, especially for molding, an insert film in which a pattern is printed on the surface of the film and then three-dimensionally molded in a state of being softened by heating is well known, but a hard coat resin layer applied to the film is used. When it is made hard, microcracks are likely to occur on the curved surface when it is processed into a three-dimensional shape, and there are restrictions on the processed shape. Therefore, in the past, the applicant has applied a hard coat agent containing a triazine ring-containing (meth) acrylate prepolymer and organic fine particles having an average primary particle size of 80 to 500 nm as a hard coat resin for insert molding that achieves both surface hardness and moldability. Was invented (Patent Document 1). This hard coating agent had a film thickness of 1 to 10 μm and was excellent in that it had both sufficient flexibility and surface physical characteristics.

By selecting a hard coating agent suitable for such molding applications, restrictions on the processing surface have been relaxed to some extent, but there are cases where the extensibility is still insufficient in applications that require deep narrowing down. In addition, in applications that are frequently touched by human hands, such as in the interior field of automobiles, there is a problem that the hand cream on the surface of the hand attacks the surface film of the hard coat, and the surface film peels off after long-term use, so good processing is performed. There was room for improvement in order to achieve both characteristics (stretchability) and chemical resistance.

Patent No. 4848200

The subject of the present invention is that it has abrasion resistance and nail scratch resistance, has high breaking elongation and good moldability, and also has excellent chemical resistance, and is photocurable suitable for in-mold molding and insert molding. It is an object of the present invention to provide a sex resin composition and a hard coat film for molding coated with the same.

In order to solve the above problems, the invention of claim 1 is a urethane acrylate obtained by further reacting pentaerythritol triacrylate (hereinafter referred to as PETA) with diisocyanate obtained by reacting ethylene glycol with isophorone diisocyanate (hereinafter referred to as IPDI). It contains (A), a surface conditioner (B), and a photopolymerization initiator (C), and the blending amount of the above (B) is 0.3 to 3.0% by weight based on the total solid content. Provided is a characteristic photocurable resin composition.

The invention of claim 2 provides the photocurable resin composition according to claim 1, wherein the weight average molecular weight of (A) is 1500 to 30,000.

The invention of claim 3 provides the photocurable resin composition according to claim 1 or 2, wherein the blending amount of the above (A) is 65 to 97% by weight with respect to the total solid content. ..

The invention of claim 4 provides the photocurable resin composition according to any one of claims 1 to 3, further comprising a light stabilizer (D).

The invention of claim 5 provides the photocurable resin composition according to any one of claims 1 to 4, further comprising an antiviral agent (E).

The invention of claim 6 provides a hard coat film characterized by having a cured layer of the photocurable resin composition according to any one of claims 1 to 5 on a plastic base material.

The invention of claim 7 provides the hard coat film of claim 6, characterized in that it is a molding film.

The invention of claim 8 provides a plastic molded product using the hard coat film according to claim 7.

The photocurable resin composition of the present invention has abrasion resistance and nail scratch resistance, has high breaking elongation and good moldability, and is also excellent in chemical resistance, and is in-mold molded or insert molded. It is useful as a hard coat resin to be applied to a molding film used for such purposes.

The composition of the photocurable resin composition of the present invention is a urethane acrylate (A) obtained by further reacting PETA with a diisocyanate obtained by reacting ethylene glycol and IPDI, a surface conditioner (B), and a photopolymerization initiator. (C). In addition, in this specification, (meth) acrylate includes both acrylate and methacrylate.

The IPDI of the alicyclic diisocyanate used in the synthesis of (A) has no yellowing and is excellent in weather resistance stability, and at the same time, has high rigidity and can increase the hardness of the cured product. By reacting with ethylene glycol having a very short carbon chain, it is possible to increase the concentration of urethane bonds in the molecule, and it is possible to form a main skeleton having a highly rigid linear structure with excellent chemical resistance. If polyethylene glycol is used instead of ethylene glycol, the concentration of urethane bonds is lowered and the chemical resistance is lowered, which is not suitable.

The synthesis method of (A) is not particularly limited, and a known method can be used. The reaction may be carried out in the absence of a solvent, but stirring may become difficult as the molecular weight of (A) increases. Therefore, a ketone such as butanone or an aromatic inert solvent such as xylene may be used. Further, it is preferable to use a catalyst for the reaction between the hydroxyl groups of ethylene glycol and PETA and the isocyanate group. Examples of such cases include tin-based materials such as dibutyltin dilaurate and metal alkoxide-based materials such as cobalt naphthenate. The reaction temperature can be appropriately set, but is preferably 40 to 120 ° C, more preferably 60 to 100 ° C.

Mw. Of the above (A). Is preferably 1500 to 30000, more preferably 2000 to 15000, and particularly preferably 3000 to 10000. When it is 1500 or more, sufficient elongation at break can be secured, and when it is 30,000 or less, it becomes easy to adjust the viscosity to have good workability. The Mw of (A) can be adjusted by the molar ratio of ethylene glycol to be reacted and IPDI, and when the molar ratio of IPDI to ethylene glycol is brought closer, Mw tends to increase. Mw was calculated by measuring and calculating the molecular weight in terms of standard polystyrene by gel permeation chromatography using a tetrahydrofuran eluent on a column using a filler based on styrenedivinylbenzene.

The blending amount of (A) is preferably 65 to 97% by weight, more preferably 70 to 94% by weight, based on the total solid content. Sufficient breaking strength can be ensured when the content is 65% by weight or more, and sufficient curability can be ensured when the content is 97% by weight or less.

The surface conditioner (B) used in the present invention is added for the purpose of improving the slipperiness of the surface of the cured product, and the friction coefficient is lowered due to the influence thereof, and as a result, the scratch resistance is improved. Examples thereof include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, modified polyether, and fluorine-based polymer, which can be used alone or in combination of two or more. Among these, a polydimethylsiloxane copolymer in which a polyether group is introduced into the side chain is preferable in order to improve the compatibility with the above (A).

The blending amount of (B) is 0.3 to 3.0% by weight, preferably 0.3 to 2.0% by weight, more preferably 0.4 to 1.5% by weight, based on the total solid content. If it is less than 0.3%, the cloth abrasion resistance and the nail scratch resistance are lowered due to the increase in the coefficient of friction, and if it is more than 3.0% by weight, the color reproducibility at the time of decorative printing is lowered due to the increase in haze. Examples of commercially available products include BYK-UV3500 (trade name: manufactured by BYK).

The photopolymerization initiator (C) used in the present invention generates radicals by irradiation with ultraviolet rays, electron beams, etc., and the radicals trigger a polymerization reaction, and is benzylketal-based, acetophenone-based, or phosphine oxide-based. A general-purpose photopolymerization initiator can be used. By arbitrarily selecting the light absorption wavelength of the polymerization initiator, curability can be imparted over a wide wavelength range from the ultraviolet region to the visible light region. Specifically, 2.2-dimethoxy-1.2-diphenylethane-1-one as a benzyl ketal system, 1-hydroxy-cyclohexyl-phenyl-ketone and 1- [4- (2- (2- (2-)) as an α-hydroxyacetophenone system. Hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one is a 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1 as an α-aminoacetophenone system. -On includes 2.4.6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2.4.6-trimethylbenzoyl) -phenylphosphine oxide as acylphosphine oxide systems, alone or in combination of two or more. Can be used in combination.

Among these, it is preferable to contain an α-hydroxyacetophenone system that does not easily turn yellow, and commercially available products include Omnirad 127, 184, and 2959 (trade name: manufactured by IGM Resins). The composition of the above (B) with respect to 100 parts by weight of the radically polymerizable content is preferably 2 to 12 parts by weight, more preferably 3 to 10 parts by weight.

It is preferable to further add a light stabilizer (D) to the composition of the present invention. Examples of (D) include ultraviolet absorbers and radical scavengers. The former includes benzotriazoles, benzophenones, triazines and the like, and the latter includes hindered amines (hereinafter referred to as HALS) and hindered phenols. Among these, triazine-based and hindered amine-based products are preferable, and commercially available products include Tinuvin 400 (trade name: manufactured by BASF Japan, hydroxyphenyl triazine-based), Tinuvin 123 (trade name: manufactured by BASF Japan, HALS-based) and the like. The blending amount is preferably 0.1 to 5% by weight based on the total solid content.

By further adding an antiviral agent (E) to the composition of the present invention, it is possible to impart antiviral properties. Examples of the inorganic material having antiviral properties include compounds containing copper, silver, titanium, tin, iron, nickel, zinc and the like, and examples of the organic material include hydroxyapatite, a polymer having a sulfonic acid group or a salt thereof and the like. Be done.

The blending amount of the composition (F) with respect to the total solid content is preferably 3 to 30% by weight, more preferably 5 to 20% by weight. When the content is 3% by weight or more, antiviral properties can be imparted, and when the content is 30% by weight or less, sufficient appearance and coating film performance can be ensured.

The compositions of the present invention include reactive diluents, UV absorbers, adhesion promoters, antioxidants, brewing agents, pigments, leveling agents, defoamers, and more, as needed, to the extent that performance is not impaired. Thickeners, anti-settling agents, antistatic agents, antifoaming agents, antibacterial agents, waxes, matting agents, hydrophilic agents, water repellents and the like may be added. However, it is preferable not to mix inorganic fillers such as silica oxide and alumina because they may reduce the abrasion resistance of the cloth.

As the reactive diluent, a (meth) acrylate monomer is preferable, and a polyfunctional (meth) acrylate is more preferable. If only a large amount of monofunctional (meth) acrylate is blended, the molecular weight of the cured product does not increase and the elongation at break and chemical resistance tend to decrease. The blending amount is preferably 20% by weight or less based on the total solid content, and if the blending amount is large, curing tends to proceed excessively and the elongation at break tends to decrease. In particular, pentaerythritol hexaacrylate (hereinafter referred to as DPHA) or the like is preferable, and the reactivity is improved even when added in a small amount.

To improve coating characteristics when coating on plastic substrates. Dilute with a solvent such as toluene, isobutanol, ethyl acetate, butyl acetate, hexane, cyclohexane, cyclohexanone, methylcyclohexanone, acetone, methyl ethyl ketone (hereinafter referred to as MEK), methyl isobutyl ketone, propylene glycol monomethyl ether (hereinafter referred to as PGM). You may. An example of the solid content when diluting is 20 to 50%, but there is no particular specification, and the viscosity can be appropriately set so as to have a viscosity that is easy to apply.

Examples of the plastic base material to which the photocurable resin composition is applied include polyester film, triacetyl cellulose film, polycarbonate (hereinafter referred to as PC) film, polysulphon film, nylon film, cycloolefin film, and acrylic (hereinafter referred to as PMMA). ) Film, polyimide film, ABS film, polyolefin film, PVC film, PVA film and the like. Among them, a biaxially stretched polyester film is preferably used from the viewpoints of weather resistance, workability, dimensional stability and the like. Further, a PMMA film or a PC film is preferably used for decorating an automobile interior, and a laminated film thereof may also be used. The thickness of the film may be approximately 25 μm to 500 μm.

For the purpose of improving the adhesion of the plastic base material to the photocurable resin composition, the surface is roughened by a primer treatment, a sandblasting method, a solvent treatment method, etc., or a corona discharge treatment, a chromic acid treatment, ozone. Surface treatment such as surface oxidation treatment such as ultraviolet irradiation treatment can be performed. On the contrary, since it is used for transfer purposes, primer treatment with a release agent such as a silicone resin or a fluororesin may be performed for the purpose of improving the release property.

The method for applying the composition is not particularly limited, and is a coating method such as a known spray coat, roll coat, die coat, air knife coat, blade coat, spin coat, reverse coat, gravure coat, wire bar, or gravure printing, screen. It can be formed by a printing method such as printing, offset printing, or inkjet printing. The film thickness to be applied can be exemplified, but is not limited to 1 μm to 10 μm when dried.

Examples of the ultraviolet irradiation light source used for curing the composition include a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, an LED lamp, and an electrodeless ultraviolet lamp. The atmosphere to be irradiated may be air or an inert gas such as nitrogen or argon. Further, the curability can be further improved by heating the back roll at the time of ultraviolet irradiation or heating the coating film with an IR heater or the like. The irradiation condition irradiation intensity ^{500mW / cm 2 ~3000mW / cm 2} , the exposure amount 50~400mJ / cm ² is illustrated, but is not limited thereto.

The hard coat film obtained by coating and curing the composition on a plastic base material preferably has a breaking elongation of 100% or more in an atmosphere of 130 ° C., more preferably 150% or more. If the elongation at break is less than 100%, cracks may occur during molding in applications with deep drawing.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but specific examples are shown, and the present invention is not particularly limited thereto. Unless otherwise specified, the measurement was performed under the conditions of room temperature of 25 ° C. and relative humidity of 65%.

Preparation of Oligomer A 200 parts by weight of ethylene glycol (hereinafter referred to as EG) and 835 parts by weight of IPDI (trade name: Death Module INTO group 37.5% manufactured by Sumika Bayer Urethane Co., Ltd.) in MEK solvent together with a catalyst. In addition to (solid content 50%), the mixture was stirred and reacted at 30 ° C. for 30 minutes, and the reaction was terminated when the peak of the isocyanate group reached a predetermined amount in the infrared absorption analysis. Next, 230 parts by weight of PETA (trade name PET30 solid content 100% manufactured by Nippon Kayaku Co., Ltd.) was added, and the mixture was stirred and reacted at 10 ° C. for 30 minutes, then stirred and reacted at 60 ° C. for 30 minutes for infrared absorption. After confirming that the isocyanate group had disappeared by analysis, the solid content was adjusted to 50% by MEK, and Mw. 6,000 hexafunctional oligomers A were obtained.

Preparation of Oligomer B 200 parts by weight of ethylene glycol (hereinafter referred to as EG) and 798 parts by weight of IPDI (trade name: Death Module INTO group 37.5% manufactured by Sumika Bayer Urethane Co., Ltd.) in MEK solvent together with a catalyst. In addition to (solid content 40%), the mixture was stirred and reacted at 30 ° C. for 30 minutes, and the reaction was terminated when the peak of the isocyanate group reached a predetermined amount in the infrared absorption analysis. Next, 150 parts by weight of PETA (trade name PET30 solid content 100% manufactured by Nippon Kayaku Co., Ltd.) was added, and the mixture was stirred and reacted at 10 ° C. for 30 minutes, then stirred and reacted at 60 ° C. for 30 minutes for infrared absorption. After confirming that the isocyanate group had disappeared by analysis, the solid content was adjusted to 50% by MEK, and Mw. 8,000 hexafunctional oligomers B were obtained.

Preparation of Oligomer C 200 parts by weight of ethylene glycol (hereinafter referred to as EG) and 922 parts by weight of IPDI (trade name: Death Module INTO group 37.5% manufactured by Sumika Bayer Urethane Co., Ltd.) in MEK solvent together with a catalyst. In addition to (solid content 60%), the mixture was stirred and reacted at 30 ° C. for 30 minutes, and the reaction was terminated when the peak of the isocyanate group reached a predetermined amount in the infrared absorption analysis. Next, 400 parts by weight of PETA (trade name PET30 solid content 100% manufactured by Nippon Kayaku Co., Ltd.) was added, and the mixture was stirred and reacted at 10 ° C. for 30 minutes, then stirred and reacted at 60 ° C. for 30 minutes for infrared absorption. After confirming that the isocyanate group had disappeared by analysis, the solid content was adjusted to 50% with MEK, and Mw. 4,200 hexafunctional oligomers C were obtained.

Urethane acrylates (hereinafter referred to as ureac) 1 to 3 having the following skeletons were obtained according to the above production method.
Ureaku 1: PETA-IPDI-Polyethylene glycol-IPDI-PETA skeleton,
Hexafunctional, solid content 50%, Mw. 5500
Ureaku 2: PETA-IPDI-Polycarbonate Diol-IPDI-PETA Skeleton,
Hexafunctional, solid content 50%, Mw. 22000
Ureaku 3: PETA-IPDI-cyclohexanediol-IPDI-PETA skeleton, hexafunctional, solid content 50%, Mw. 7000

Examples The oligomers A to C prepared above as (A), BYK-UV3500 (trade name: manufactured by BYK) as (B), and Omnirad 2959 and 127 (trade name: IGM) as (C). Resins), Tinuvin 400 and 123 (trade name: BASF Japan) as (D), Slanimo D100 (trade name: Osaka Gas Chemical) and Amorden V-100JM (trade name: Yamato) as (E). (Manufactured by Kagaku Kogyo Co., Ltd.) and Marcaside V-1 (trade name: manufactured by Osaka Kasei Co., Ltd.) are stirred with DPHA as a reactive diluent until they are uniformly dissolved and dispersed in the formulation shown in Table 1, and the solid content is further increased. PGM was added so as to be 30%, and the mixture was diluted and stirred to obtain the photocurable resin compositions of Examples 1 to 13. The unit of the formulation table is the part by weight.

Comparative Example In addition to the materials used in Examples, the above-mentioned ureacs 1 to 3 as oligomers were stirred with the formulation shown in Table 2 until they were uniformly dissolved and dispersed so that the solid content was 30%. PGM was added and diluted and stirred to obtain the photocurable resin compositions of Comparative Examples 1 to 6.

Table 1

Table 2

The evaluation method was as follows.

Preparation of hard coat film The photocurable resin composition prepared in Examples and Comparative Examples was applied to PMMA film 505 NAH (trade name: Kaneka Co., Ltd., thickness 75 μm) so that the dry film thickness was 3 μm. After being applied and dried, it was cured with a high-pressure mercury lamp 200 mJ to obtain a hard coat film.

Total light transmittance, haze: Measured using Haze-GARD2 manufactured by Toyo Seiki Seisakusho in accordance with JIS K7361-1. Total light transmittance is 90% or more ○, less than 90% ×, haze 1. 5% or less was evaluated as ◯, and more than 1.5% was evaluated as x.

Adhesion: In accordance with the cross-cut method of JIS K 5600-5-6, squares are created in 10x10 at 1 mm intervals on the coated surface, and cellophane tape CT-24 (trade name: manufactured by Nichiban Co., Ltd.) is attached. The state of peeling was confirmed by pulling upward. Without peeling: 100/100, with peeling: 0/100 to 99/100

Cloth wear resistance: Using the friction tester FR-IBS manufactured by Suga Test Instruments Co., Ltd., the resin composition coated surface of the hard coat film was 9N with a friction element (diameter 16 mm) to which a white cotton cloth for testing (Kanakin No. 3) was attached. A load was applied to reciprocate 100 mm at a speed of 1 reciprocation / 1 second, and the presence or absence of scratches after 1000 reciprocations was confirmed.

Elongation at break: A hard coat film is cut into a width of 25 mm and a length of 50 mm, and a tensile test is performed using Minebea's TechnoGraph TGI-1KN at an atmospheric temperature of 130 ° C. and a tensile speed of 300 mm / min. A rate of 100% or more was evaluated as ◯, and a rate of 150% or more was evaluated as ⊚.
Calculation formula: Calculated based on how many mm is extended based on 50 mm.
Elongated length (mm) / 50 mm x 100 = Elongation rate%

Nail scratch resistance: The resin composition coated surface of the hard coat film was scratched with a nail with an arbitrary force on the glass, and the presence or absence of scratches was confirmed.

Dynamic friction coefficient: Using the automatic friction and wear analyzer Triboster TS501 manufactured by Kyowa Interface Science, a load of 100 g is applied with a point contactor (steel ball), and the dynamic friction coefficient is measured by reciprocating 50 mm width. did.

Static friction coefficient: The static friction coefficient was measured using the same method as the dynamic friction coefficient, and 0.200 or less was marked with ◯.

Chemical resistance: Hand cream and Neutrogena SPF45 (trade name: manufactured by Johnson & Johnson) were applied to the cured film, allowed to stand at 80 ° C. for 24 hours, then returned to room temperature, wiped off, and then the surface was observed. No trace of application was marked with ◯, and with trace was marked with x.

Antiviral activity value: Measured by the plaque measurement method of ISO 21702: 2019. Influenza A virus and feline calicivirus were used as test viruses, and the virus infectivity titer was measured after 24 hours. The difference in virus infectious titer from the blank film was defined as the antiviral activity value, and more than 2.0 was marked with ◯ and 2.0 or less was marked with x.

Example evaluation results Table 3

Comparative example Evaluation result Table 4

In the examples, there were no problems in all aspects such as total light transmittance, haze, adhesion, cloth abrasion resistance, elongation at break, nail scratch resistance, coefficient of dynamic friction, coefficient of static friction, and chemical resistance, which were good. In addition, Examples 8 to 13 containing an antiviral agent showed good antiviral activity values.

On the other hand, Comparative Example 1 in which (B) was not blended had a high friction coefficient and poor cloth abrasion resistance and nail scratch resistance, and Comparative Example 2 below the lower limit had a good friction coefficient but was high in resistance. The cloth abrasion property was poor, and the haze was high in Comparative Example 3 which exceeded the upper limit. Further, Comparative Example 4 containing a polyethylene skeleton oligomer and Comparative Examples 5 and 6 containing oligomers having different polyol portions had poor chemical resistance, and none of them was suitable for the present invention.

The photocurable resin composition of the present invention has high hardness, high breaking elongation, good moldability, and excellent chemical resistance, and can be used as a resin to be applied to a hard coat film used for insert molding or the like. It is useful.

Claims (8)

The diisocyanate obtained by reacting ethylene glycol with isophorone diisocyanate contains urethane acrylate (A) obtained by further reacting pentaerythritol triacrylate, a surface conditioner (B), and a photopolymerization initiator (C). ) Is 0.3 to 3.0% by weight based on the total solid content of the photocurable resin composition. The photocurable resin composition according to claim 1, wherein the weight average molecular weight of (A) is 1500 to 30000. The photocurable resin composition according to claim 1 or 2, wherein the blending amount of (A) is 65 to 97% by weight based on the total solid content. The photocurable resin composition according to any one of claims 1 to 3, further comprising a light stabilizer (D). The photocurable resin composition according to any one of claims 1 to 4, further comprising an antiviral agent (E). A hard coat film comprising a cured layer of the photocurable resin composition according to any one of claims 1 to 5 on a plastic base material. The hard coat film according to claim 6, wherein the film is a molding film. A plastic molded product using the hard coat film according to claim 7.