JP2011052143A - Curable resin composition and molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable resin composition formable of a hard coat layer that gives good scratch resistance even in Taber abrasion test and also is excellent in transparency, and a molding obtained by applying and curing the same. <P>SOLUTION: The hard coat layer is formed by applying the curable resin composition containing: a colloidal silica-containing monomer (A) obtained by reacting colloidal silica (a1) with an isocyanate compound (a2) having an isocyanate group and a polymerizable unsaturated group; and a multifunctional (meth)acrylate compound (B) having three or more (meth)acryloyl groups, to a plastic molding and curing the same. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a curable resin composition and a molded product.

  In recent years, active energy ray-curable coatings have been used as hard coating agents in place of conventional thermosetting coatings in mobile phones, home appliances, optical films and the like. Active energy ray curable paints are rapidly spreading compared to thermosetting paints because they are fast and have good productivity, can save energy, and have excellent hardness.

  A conventional hard coating agent using an organic material is excellent in hardness, but has insufficient scratch resistance. Thus, improvement of scratch resistance by the combined use of an inorganic material and an organic material has been studied, but sufficient scratch resistance is not obtained by simply mixing an inorganic material and an organic material.

Patent Documents 1 and 2 disclose hard coat agents in which silica, which is an inorganic material, and an organic material are chemically bonded. Although these steel steel tests, which are one of the scratch resistance test methods, have obtained good results, the Taber abrasion test has not obtained sufficient values, leaving room for improvement. . In addition, since both of them require the silica content in the composition to be a certain level or more, the transparency of the formed cured film is not sufficient and it is economically disadvantageous.
JP 2004-143201 A Japanese Patent No. 4169737

  The subject of this invention is providing the curable resin composition in which the hard-coat layer from which favorable abrasion resistance is acquired also in a Taber abrasion test is formed, and the molding which apply | coated and hardened this. Another object of the present invention is to provide a curable resin composition in which a hard coat layer excellent in transparency is formed and which is economically excellent, and a molded product obtained by applying and curing the curable resin composition.

  As a result of intensive studies by the present inventors, sufficient hardness can be obtained even when the colloidal silica content is low by using a (meth) acrylate compound having three or more (meth) acryloyl groups. It was found that the transparency of the hard coat layer was improved by the fact that the scratch resistance was obtained and the colloidal silica content could be reduced.

  The invention of claim 1 includes a colloidal silica-containing monomer (A) obtained by reacting colloidal silica (a1) with an isocyanate compound (a2) having an isocyanate group and a polymerizable unsaturated group, and three or more. And a polyfunctional (meth) acrylate compound (B) having a (meth) acryloyl group, and having a silica content of 5 to 50% by weight in solid content.

According to the invention of claim 2, when a hard coat layer is formed by applying and curing a curable resin composition on an acrylic plate and haze is measured, and haze is measured again after the Taber abrasion test, increase in haze is observed. The curable resin composition according to claim 1, wherein the content is 20% or less.

  A third aspect of the present invention is the curable resin composition according to the first or second aspect, wherein the silica content is 5 to 20% by weight in solid content ratio.

  A fourth aspect of the present invention is a molded article in which the curable resin composition according to any one of the first to third aspects is applied.

  The invention according to claim 5 is the molded article according to claim 4, characterized in that the base material of the molded article is plastic.

  The curable resin composition of the present invention is suitable as a hard coat agent used for mobile phones, home appliances, optical films, and the like because it can form a hard coat layer that provides good scratch resistance even in the Taber abrasion test. . Moreover, since the curable resin composition of this invention can reduce silica content, it is excellent in transparency of a hard-coat layer, and is excellent also economically.

Hereinafter, the present invention will be described in detail.
The colloidal silica-containing monomer (A) used in the present invention is obtained by reacting colloidal silica (a1) with an isocyanate compound (a2) having an isocyanate group and a polymerizable unsaturated group.

  The colloidal silica (a1) is not particularly limited, but various commercial products having an average particle diameter of 100 nm or less and an organic solvent as a dispersion medium can be used. When silica having a larger particle size is used, not only the storage stability is deteriorated, but also the desired wear property of the present invention cannot be expressed, and the obtained cured product becomes cloudy and becomes transparent. There are problems such as lacking. Those having an average particle diameter of 5 to 50 nm are more preferred. It is desirable to use colloidal silica in which some of the hydroxyl groups present on the silica surface are chemically modified and have a hydrophobic group that can be dispersed in an organic solvent. More preferably, a hydrophobic organic material having a water solubility of 0.1 to 12% by weight, wherein a part of hydroxyl groups on the surface of colloidal silica is modified with a silylating agent such as a disiloxane compound and / or a monoalkoxysilane compound. It is desirable that it is colloidally dispersed in a solvent.

  Examples of the organic solvent as a dispersion medium for colloidal silica include methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, ethyl acetate, n-butyl acetate, diisopropyl ether, and dibutyl ether. Examples of the reactive solvent include acrylic monomers including methyl methacrylate.

  Examples of the isocyanate compound (a2) having an isocyanate group and a polymerizable unsaturated group include acryloyl isocyanate, methacryloyl isocyanate, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, and the like. A compound obtained by reacting a compound having two or more isocyanate groups with a compound having a functional group capable of reacting with a polymerizable unsaturated group and an isocyanate group may be used.

Examples of the compound having two or more isocyanate groups include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5- Naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3′-dimethyl-4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane triisocyanate, 3,3′- Dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), 2,2,4-trimethyl Xamethylene diisocyanate, bis (2-isocyanatoethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, A trimethylolpropane adduct of 2,5-bis (isocyanatemethyl) -bicyclo [2.2.1] heptane, 2,6-bis (isocyanatemethyl) -bicyclo [2.2.1] heptane, triethylene diisocyanate, Isocyanurate of triethylene diisocyanate, oligomer of diphenylmethane-4,4′-diisocyanate, biuret of hexamethylene diisocyanate, hexame Isocyanurate of tolylene diisocyanate, uretdione of hexamethylene diisocyanate, isocyanurate and the like of isophorone diisocyanate.
These compounds can be used alone or in combination of two or more.

Examples of the compound having a functional group capable of reacting with a polymerizable unsaturated group and an isocyanate group include a hydroxyl group-containing monofunctional acrylate and a hydroxyl group-containing polyfunctional acrylate. Specific examples of the hydroxyl group-containing monofunctional acrylate include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and polyethylene glycol acrylate. Specific examples of the hydroxyl group-containing polyfunctional acrylate include trimethylolpropane diacrylate, ethoxylated trimethylolpropane diacrylate, propoxylated trimethylolpropane diacrylate, pentaerythritol tri (meth) acrylate, and the like.
In particular, when a 3-6 functional acrylate containing a hydroxyl group is used, the degree of cross-linking is improved, so the scratch resistance of the cured film is improved, and problems such as discoloration due to residual unsaturated groups can be avoided.

Further, (meth) acrylic acid, itaconic acid, cinnamic acid, maleic acid, fumaric acid, 2- (meth) acryloxypropyl hexahydrophthalate, 2- (meth) acryloxyethyl hexahydrophthalate, etc. Unsaturated aliphatic carboxylic acids such as 2- (meth) acryloxypropyl phthalate, 2- (meth) acryloxypropyl ethyl phthalate and the like, aromatic aromatic carboxylic acids having a carboxyl group, vinyloxyethylamine Amino group-containing monomers such as vinyl oxide decylamine, allyloxypropylamine, 2-methylallyloxyhexylamine, and vinyloxy- (2-hydroxy) butylamine can also be used.
These compounds having a polymerizable unsaturated group and a functional group capable of reacting with an isocyanate group can be used alone or in combination of two or more.

  When reacting a compound having two or more isocyanate groups with a compound having a polymerizable unsaturated group and a functional group capable of reacting with an isocyanate group, a catalyst may be added. For example, copper naphthenate, cobalt naphthenate, zinc naphthenate, di-n-butyltin laurate, triethylamine, 1,4-diazabicyclo [2.2.2] octane, 2,6,7-trimethyl-1,4-diazabicyclo [2.2.2] It is preferable to use 0.01 to 1 part by weight of a urethanization catalyst such as octane with respect to 100 parts by weight of the total amount of reactants. These catalysts can be used when the colloidal silica (a1) is reacted with an isocyanate compound (a2) having an isocyanate group and a polymerizable unsaturated group.

  In addition, when reacting a compound having two or more isocyanate groups with a compound having a polymerizable unsaturated group and a functional group capable of reacting with an isocyanate group, the compound is inert to the isocyanate group in the presence of a urethane catalyst. Solvents, for example, aromatic hydrocarbon solvents such as toluene and xylene, ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as methyl ethyl ketone and cyclohexanone, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, ethyl- Glycol ether ester solvents such as 3-ethoxypropionate, ether solvents such as tetrahydrofuran and dioxane, polar solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and furfural You can use.

  When the colloidal silica (a1) is reacted with the isocyanate compound (a2) having an isocyanate group and a polymerizable unsaturated group to obtain the colloidal silica-containing monomer (A), IR measurement or amine titration is performed. The concentration of residual isocyanate groups is measured over time, and the point at which no change is observed is taken as the end point. In order to block any residual isocyanate group, an alcohol such as methyl alcohol, ethyl alcohol or isopropyl alcohol, or a compound having a functional group capable of reacting with the polymerizable unsaturated group and the isocyanate group is added. Also good. If there is a residual isocyanate group, the storability of the curable resin composition may be reduced.

  Examples of the polyfunctional (meth) acrylate compound (B) having three or more (meth) acryloyl groups include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dipentaerythritol triacrylate, and propionic acid-modified dipentaerythritol triacrylate. , Pentaerythritol triacrylate, propylene oxide modified trimethylolpropane triacrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol pentaacrylate, propionic acid modified dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, caprolactone modified dipentaerythritol Hexaacrylate, ethoxylated trimethylolpropane trimethacrylate, Urethane acrylate oligomer these oligomerized, epoxy acrylate oligomer, polyester acrylate oligomer and a polyfunctional acrylate oligomer such as acryl acrylate oligomer. An acrylate having a larger number of functional groups is preferable because it has a higher surface hardness. You may use these individually or in mixture of 2 or more types.

  The silica content in the curable resin composition is preferably 5 to 50% by weight in solid content, and more preferably 5 to 20% by weight or more. When the silica content is less than 5% by weight, the wear resistance is lowered, and when it exceeds 50% by weight, the organic material that becomes the binder is relatively reduced. Silica tends to be missing from the coating film. Moreover, when the silica content is 5 to 20% by weight, the formed hard coat layer is excellent in transparency and economically excellent.

  Since the curable resin composition of the present invention has an unsaturated group, it can be cured in the presence of a suitable polymerization initiator. When a photopolymerization initiator is used, it can be cured in a short time by irradiating with active energy rays such as ultraviolet rays, so that productivity can be improved and energy saving can be achieved.

  Examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, Carbonyl compounds such as benzoin isopropyl ether, sulfur compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, and tetramethylthiuram disulfide can be used.

  Commercially available products of these photopolymerization initiators include Irgacure 184, 369, 651, 500 (Ciba Specialty Chemicals), Lucirin LR8728 (BASF), Darocur 1116, 1173 (Merck), Ubekrill P36 (UCB) ) And the like.

  In the curable resin composition used in the present invention, various resins such as acrylic resins, urethane resins, styrene resins, phenol resins, melamine resins, barium hydroxide, magnesium hydroxide, In addition to inorganic fillers such as aluminum hydroxide, silicon oxide, titanium oxide, calcium sulfate, barium sulfate, calcium carbonate, basic zinc carbonate, basic lead carbonate, silica sand, clay, talc, silica compound, titanium dioxide, silane series And titanate coupling agents, bactericides, preservatives, plasticizers, flow regulators, antistatic agents, thickeners, pH adjusters, surfactants, leveling regulators, antifoaming agents, color pigments, You may add compounding materials, such as a rust pigment. Moreover, you may add antioxidant and a ultraviolet absorber for the purpose of a weather resistance improvement.

  The substrate to which the curable resin composition of the present invention is applied is not particularly limited, but ABS, PC, acrylic, PS, MS, PBT, PPS, PET, TAC, etc., alone or in combination of two or more types, etc. Various plastics. In particular, transparent substrates such as PC, acrylic, PET, and TAC are optimal for display bodies such as liquid crystal panels that require wear. The shape of the substrate is not limited to a film shape or a flat plate shape, but may be a molded body.

  The method for applying the curable resin composition of the present invention on the substrate is not particularly limited, and is known spray coating, dipping, roll coating, die coating, air knife coating, blade coating, spin coating, reverse coating, gravure coating, wire. It can be formed by a coating method such as a bar or a printing method such as gravure printing, screen printing, offset printing, or ink jet printing. The thickness of the resin layer is preferably 1 μm to 40 μm. When the thickness of the resin layer is less than 1 μm, sufficient wear resistance is not generated, and when it exceeds 40 μm, cracks are generated, which is not preferable.

The cured resin composition of the present invention has good scratch resistance even in the Taber abrasion test, but the haze is measured by forming a hard coat layer by applying and curing the curable resin composition on an acrylic plate. When the haze is measured again after the Taber abrasion test, the increase in haze is preferably 20% or less.
Specifically, the curable resin composition is applied onto an acrylic plate (Asahi Kasei Chemicals, Delaglass A, 2 mm thick) by spraying, and the solvent is volatilized by drying at 80 ° C. for 1 minute, using a high-pressure mercury lamp. Is cured by irradiating at 500 mJ / cm ² to form a 10 μm thick hard coat layer on the acrylic plate.
Next, based on JIS K7136, a haze is measured using a haze meter (made by Suga Test Instruments Co., Ltd.).
Furthermore, using a sandpaper S-42 for Taber Abrasion Tester (manufactured by Daito Electron Co., Ltd.), the haze after rubbed the coating film 500 times with 500 g load was measured, and the increase in haze after the Taber abrasion test It is preferable that it is 20% or less.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and demonstrated in detail about this invention, a specific example is shown and it does not specifically limit to these.

Synthesis of colloidal silica-containing monomer Pentaerythritol triacrylate (trade name: NK Ester A-TMM-3LM-N, manufactured by Shin-Nakamura Chemical Co., Ltd.) 12 parts by weight, isophorone diisocyanate (IPDI) 4.85 parts by weight, DBTDL as catalyst By adding 0.01 parts by weight of (dibutyltin dilaurate) and reacting, pentaerythritol triacrylate-IPDI monomer was obtained. This monomer was added to 80 parts by weight of methyl isobutyl ketone-dispersed colloidal silica (manufactured by Nissan Chemical Industries, SiO ₂ component 30%, average particle size 20 nm), stirred for 24 hours at room temperature, and then isopropanol was added. The disappearance of the isocyanate group was confirmed by IR to obtain colloidal silica-containing monomer A (solid content 42%, silica content 25% in the whole monomer).

Examples 1-5
As shown in the composition of Table 1, dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., 100% solid content, trade name A) with respect to 25 to 200 parts by weight of the obtained colloidal silica-containing monomer A -DPH) is added in an amount of 20 to 90 parts by weight, Irgacure 184 as an initiator is added in an amount of 5 parts by weight, and toluene is appropriately added as a solvent so that the solid content is 30%. Thus, the curable resin compositions of Examples 1 to 5 are obtained. Obtained.

Examples 6-10
As shown in the composition of Table 1, 15 functional urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., 100% solid content, trade name U-) with respect to 25 to 200 parts by weight of the obtained colloidal silica-containing monomer A 15HA) was added in an amount of 20 to 90 parts by weight, Irgacure 184 as an initiator was added in an amount of 5 parts by weight, and toluene was added as a solvent so that the solid content was 30%, thereby obtaining curable resin compositions of Examples 6 to 10. .

Comparative Example 1
By adding 96 parts by weight of dipentaerythritol hexaacrylate, 5 parts by weight of Irgacure 184 as an initiator to 10 parts by weight of the colloidal silica-containing monomer A, and adding toluene as a solvent so that the solid content is 30%. The curable resin composition of Comparative Example 1 was obtained.

Comparative Example 2
By adding 10 parts by weight of dipentaerythritol hexaacrylate, 5 parts by weight of Irgacure 184 as an initiator to 230 parts by weight of the colloidal silica-containing monomer A, and adding toluene as a solvent so that the solid content is 30%. The curable resin composition of Comparative Example 2 was obtained.

Comparative Example 3
Example 3 was the same as Example 3 except that 60 parts by weight of triethylene glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., solid content 100%, trade name Light Acrylate 3EG-A) was added instead of dipentaerythritol hexaacrylate. The curable resin composition of Comparative Example 3 was obtained.

Comparative Example 4
Without using a colloidal silica-containing monomer, 100 parts by weight of dipentaerythritol hexaacrylate, 5 parts by weight of Irgacure 184 as an initiator, and toluene as a solvent were appropriately added to obtain a curable resin composition having a solid content of 30%.

The curable resin composition prepared in each Example and Comparative Example was sprayed on an acrylic plate (Asahi Kasei Chemicals, Delaglass A, 2 mm thickness) and dried at 80 ° C. for 1 minute to volatilize the solvent and high pressure mercury. It hardened | cured by irradiating with 500 mJ / cm < ² > using a lamp | ramp, the hard-coat layer with a film thickness of 10 micrometers was formed on the acrylic board, and test evaluation was performed with the following method.

Measurement of total light transmittance Based on JIS K 7136, haze was measured using a haze meter (manufactured by Suga Test Instruments Co., Ltd.).

Measurement of haze Haze was measured based on JIS K 7136 using a haze meter (manufactured by Suga Test Instruments Co., Ltd.).

Measurement of Pencil Hardness Based on JIS K 5600-5-4, a pencil scratch coating film hardness tester (type P) manufactured by Toyo Seiki Seisakusho was used with a 1 kg load.

Evaluation of Abrasion Using a sandpaper S-42 for Taber Abrasion Tester (manufactured by Daito Electron Co., Ltd.), measuring the haze after rubbing the coating film 500 times with 500 g load, from the haze before the Taber abrasion test The amount of increase was calculated.

  As shown in Table 1, the test specimens using the resin compositions of the examples were very excellent in wear resistance. In particular, those having a silica content of 5 to 20% by weight were excellent in transparency. On the other hand, as shown in Table 2, when the amount of silica is insufficient or excessive, or when a polyfunctional (meth) acrylate compound having three or more (meth) acryloyl groups is not used, the result is inferior in wear resistance. It was.

Claims (5)

  A colloidal silica-containing monomer (A) obtained by reacting colloidal silica (a1) with an isocyanate compound (a2) having an isocyanate group and a polymerizable unsaturated group, and three or more (meth) acryloyl groups. A curable resin composition comprising a polyfunctional (meth) acrylate compound (B) having a silica content of 5 to 50% by weight in solid content.   A hard coat layer is formed by applying and curing a curable resin composition on an acrylic plate, and haze is measured. When haze is measured again after the Taber abrasion test, the increase in haze is 20% or less. The curable resin composition according to claim 1, wherein   The curable resin composition according to claim 1 or 2, wherein the silica content is 5 to 20 wt% in solid content.   A molded product, wherein the curable resin composition according to claim 1 is applied.   5. The molded product according to claim 4, wherein a base material of the molded product is plastic.