Active energy ray curable composition for circuit protection, and laminate using the same

Abstract

To provide an active energy ray curable composition for circuit protection that exhibits good adhesion and flexibility. [Solution] An active energy ray curable composition for circuit protection containing a urethane (meth)acrylate monomer (A) and a bisphenol-type epoxy (meth)acrylate monomer (B), characterized in that the content of monomer (A) is 20 to 40% by mass of the entire composition, the content of monomer (B) is 5 to 30% by mass of the entire composition, and the mass ratio (A):(B) of monomer (A) to monomer (B) is 1.3:1 to 5:1.

Description

Technical Field

[0001] The present invention relates to an active energy ray curable composition used for circuit protection on a conductive circuit and a laminate using the same.

Background Art

[0002] Conventionally, a solder resist film (circuit protection layer) used for wiring boards such as flexible wiring boards and electrode substrates for touch panels has used a resin material having insulation properties. For example, an ultraviolet curable resin composition may be applied onto a conductive circuit formed on a film base material such as a polyethylene terephthalate film (PET film), a polyimide film, or a polyester film to form a solder resist film. As the conductive circuit, a conductive layer made of a conductive polymer, a circuit formed by etching a metal foil, or the like is used. However, conventional ultraviolet curable resin compositions have had a problem of poor adhesion to poorly adherent materials such as the above film base materials and conductive layers made of conductive polymers. In addition, conductive circuits made of conductive polymers are widely used in flexible products, and the protective layers of these conductive circuits are required to have flexibility (flexural resistance) that can follow the deformation of the base material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the active energy ray curable composition for circuit protection described in Patent Document 1 still has a problem that the flexural resistance is not sufficient, and the product development for flexible applications is limited.

[0005] Therefore, the present invention aims to provide an active energy ray curable composition for circuit protection that exhibits good adhesion and flexibility. [Means for solving the problem]

[0006] [1] An active energy ray curable composition for circuit protection containing a urethane (meth)acrylate monomer (A) and a bisphenol-type epoxy (meth)acrylate monomer (B), The content of the monomer (A) is 20 to 40% by mass of the entire composition. The content of the monomer (B) is 5 to 30% by mass of the entire composition, and An active energy ray curable composition for circuit protection, characterized in that the mass ratio (A):(B) of monomer (A) to monomer (B) is 1.3:1 to 5:1. [2] The circuit protection active energy ray curable composition according to [1] further comprising a (meth)acrylate monomer (C) other than urethane (meth)acrylate monomer (A) and bisphenol-type epoxy (meth)acrylate monomer (B). [3] The active energy ray curable composition according to [1] or [2], wherein the (meth)acrylic monomer (C) other than urethane (meth)acrylate monomer (A) and bisphenol-type epoxy (meth)acrylate monomer (B) is a monofunctional monomer. [4] The circuit protection active energy ray curable composition according to any one of [1] to [3] further comprising an ultraviolet absorber, a light stabilizer, and a photopolymerization initiator. [5] A laminate comprising a substrate, a conductive circuit, and a protective layer made of an active energy ray curable composition for circuit protection described in any of [1] to [4]. [6] The laminate according to [5], wherein the conductive circuit comprises a conductive polymer. [7] The laminate according to [5], wherein the base material is a flexible base material. [8] A substrate having a conductive circuit contains a urethane (meth)acrylate monomer (A) and a bisphenol-type epoxy (meth)acrylate monomer (B), The content of the monomer (A) is 20 to 40% by mass of the entire composition. The content of the monomer (B) is 5 to 30% by mass of the entire composition, and A circuit protection active energy ray curable composition having a mass ratio (A):(B) of monomer (A) to monomer (B) of 1.3:1 to 5:1 is coated or printed. A method for manufacturing laminates, in which a protective layer is formed by curing with active energy rays. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide an active energy ray curable composition for circuit protection that has good adhesion and flexibility. In particular, it exhibits good adhesion even to difficult-to-adhere substrates such as film substrates and conductive polymer layers, and by coating with the active energy ray curable composition of the present invention, it is possible to obtain flexible wiring boards and electrode substrates for touch panels that have a cured coating with excellent adhesion without impairing flexibility. [Modes for carrying out the invention]

[0008] The details of the present invention are described below. In this invention, "(meth)acrylate" means "acrylate and / or methacrylate," and "(meth)acrylic" means "acrylic and methacrylic."

[0009] The active energy ray curable composition for circuit protection of the present invention contains urethane (meth)acrylate (A) and bisphenol-type epoxy (meth)acrylate (B), wherein the monomer (A) content is 20 to 40% by mass of the total composition, the monomer (B) content is 5 to 30% by mass of the total composition, and by setting the mass ratio (A):(B) of monomer (A) to monomer (B) to 1.3:1 to 5:1, both flexibility and adhesion can be achieved.

[0010] <Urethane (meth)acrylate monomer (A)> The urethane (meth)acrylate monomer (A) used in the present invention may be any (meth)acrylic urethane resin obtained by reacting a urethane resin with (meth)acrylic acid, and is not limited to any specific compound. The urethane (meth)acrylate monomer (A) can form a cured coating film with good flexibility, and is effective for applications such as wiring boards, especially flexible wiring boards.

[0011] The urethane (meth)acrylate monomer (A) may consist of a polyol compound and a polyisocyanate compound, and its skeleton is not particularly limited, with examples including ester, ether, and carbonate types. Furthermore, the number of functional groups in one molecule is not particularly limited, but since a large number of functional groups may lead to curing shrinkage and a decrease in flexural resistance, the number of functional groups in one molecule is preferably 2 to 4. In this specification, the number of functional groups refers to the number of (meth)acryloyl groups and other radically polymerizable functional groups.

[0012] The monomer (A) content is 20 to 40% by mass of the total active energy ray curable composition, preferably 25 to 40% by mass, and more preferably 30 to 40% by mass. Within this range, good flexural resistance is achieved.

[0013] <Bisphenol-type epoxy (meth)acrylate monomer (B)> The bisphenol-type epoxy (meth)acrylate monomer (B) used in the present invention is not particularly limited, as it may be any compound obtained by esterifying a bisphenol-type epoxy resin having two or more epoxy groups in one molecule with (meth)acrylic acid. Since the bisphenol-type epoxy (meth)acrylate monomer (B) has (meth)acrylic groups that can be radically polymerized by active energy ray irradiation, the crosslinking density of the cured product is increased, further improving curability, and the cured product can be given flexibility. Furthermore, if the monomer (B) is of the bisphenol A type, it is preferable because it has good adhesion to the polymer conductive layer.

[0014] The monomer (B) content is 5 to 30% by mass of the total active energy ray curable composition, preferably 10 to 25% by mass, and more preferably 10 to 15% by mass. Adhesion is good within this range.

[0015] The mass ratio (A):(B) of the urethane (meth)acrylate monomer (A) and the bisphenol-type epoxy (meth)acrylate monomer (B) used in the present invention is 1.3:1 to 5:1. Preferably, it is 1.5:1 to 4:1, and more preferably, 2:1 to 3.5:1. Within this range, good adhesion and flexibility are obtained.

[0016] <Monomers (A) and (meth)acrylic monomers (C) other than monomer (B)> The active energy ray curable composition for circuit protection of the present invention may further use (meth)acrylic monomers (C) other than urethane (meth)acrylate monomer (A) and bisphenol-type epoxy (meth)acrylate monomer (B) to impart various physical properties. The number of functional groups of monomer (C) is not particularly limited, but it is preferably a monofunctional monomer. When a monofunctional monomer is included, adhesion and flexibility are good. Examples of monofunctional monomers include aromatic monomers such as benzyl acrylate and phenoxyethyl acrylate; saturated alicyclic monomers such as cyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate and isobornyl acrylate; heteroalicyclic monomers such as tetrahydrofurfuryl acrylate and acryloyl morpholine; aliphatic monomers such as isobutyl acrylate, t-butyl acrylate, lauryl acrylate, n-octyl acrylate, isononyl acrylate, stearyl acrylate and isostearyl acrylate; ether monomers such as ethoxyethoxyethyl acrylate and methoxypolyethylene glycol acrylate; hydroxyl group-containing monomers such as 4-hydroxybutyl acrylate, hydroxypropyl acrylate and hydroxyethyl acrylate; and acid group-containing monomers such as ω-carboxy-polycaprolactone monoacrylate.

[0017] Specific examples of the monomer (C) which is a bifunctional monomer include 1,9-nonanediol diacrylate, 1,6-hexanediol diacrylate, 1,4-butanediol diacrylate, tripropylene glycol diacrylate, tricyclodecane dimethanol diacrylate, polyethylene glycol diacrylate, and the like. Specific examples of the monomer (C) which is a trifunctional monomer include trimethylolpropane triacrylate, trimethylolethoxy triacrylate, glycerin propoxy triacrylate, pentaerythritol triacrylate, and the like. Specific examples of the monomer (C) having four or more functional groups include pentaerythritol tetraacrylate, pentaerythritol alkoxy tetraacrylate, pentaerythritol ethoxy tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hexaacrylate, and the like.

[0018] The content of the monomer (C) is preferably 1 to 30% by mass, more preferably 10 to 20% by mass, in the whole active energy ray curable composition. When it is in the above range, the flexural resistance is good. Also, the content of the monofunctional monomer is preferably 5 to 30% by mass, more preferably 10 to 20% by mass, in the whole active energy ray curable composition. When it is in the above range, the flexural resistance is good.

[0019] <Ultraviolet absorber> The active energy ray curable composition for circuit protection of the present invention can further use an ultraviolet absorber. The type of UV absorber is not particularly limited, but examples include hydroxyphenyltriazine compounds, benzotriazole compounds, benzophenone compounds, oxalic acid anilide compounds, salicylate phenyl ester compounds, and acrylonitrile compounds. Among these, hydroxyphenyltriazine compounds are preferred. These UV absorbers may be used individually or in combination of two or more.

[0020] <Light stabilizer> The circuit protection active energy ray curable composition of the present invention may further be used with a light stabilizer. Preferably, the light stabilizer is a hindered amine light stabilizer (HALS). Another preferred example of a light stabilizer is a reactive hindered amine light stabilizer that is reactive with the curable resin, i.e., has a reactive group in its molecule.

[0021] <Photopolymerization initiator> The active energy ray curable composition for circuit protection of the present invention may further use a photopolymerization initiator. The photopolymerization initiator is not particularly limited as long as it is commonly used, and examples include benzophenone initiators, thioxanthone initiators, acylphosphine oxide initiators, alkylphenone initiators, oxime ester initiators, and among these, alkylphenone initiators, 2-hydroxy-2-methylpropiophenone, 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one, 2,2'-dihydroxy-2,2'-dimethyl-1,1'-[methylenebis(4,1-phenylene)]bis(propan-1-one), 1-hydroxycyclohexylphenyl ketone, etc. These may be used individually or in combination of two or more.

[0022] <Other additives> The active energy ray curable composition for circuit protection of the present invention may further contain other additives. Examples include wear resistance improvers, polymerization inhibitors, crosslinking agents, infrared absorbers, antistatic agents, adhesion improvers, leveling agents, thixotropic agents, coupling agents, lubrication agents, antifouling agents, plasticizers, defoamers, fillers, colorants, and filler particles.

[0023] <Laminate> The laminate of the present invention comprises a substrate, a conductive circuit, and a protective layer made of the active energy ray curable composition for circuit protection of the present invention.

[0024] <Base material> The substrate is not particularly limited and can be selected as appropriate, but is preferably a flexible substrate, such as a plastic film like polyethylene terephthalate film (PET film), polyimide film, or polyester film. Among these, PET film is preferred because of its excellent heat resistance.

[0025] <Conductive Circuits> The conductive circuit is not particularly limited as long as it includes a conductive material, and can be appropriately selected according to its compatibility with the substrate. A conductive polymer is a preferred conductive material. More specifically, PEDOT / PSS, which has excellent heat resistance, is a good choice. If necessary, multiple conductive circuits, such as a conductive polymer and silver paste, may coexist. When a conductive polymer is used, the adhesion effect can be maximized.

[0026] <Laminate manufacturing process> A conductive circuit is formed on a flexible substrate by printing or coating a printing and coating solution containing a conductive material. Examples of printing or coating methods include screen printing, inkjet printing, and gravure printing. To protect the conductive circuit, a protective layer is formed by printing or coating with the circuit protection active energy ray curable composition of the present invention. Examples of printing or coating methods include screen printing, inkjet printing, and gravure printing. [Examples]

[0027] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the present invention, parts and % refer to parts by mass and mass %, respectively, unless otherwise noted.

[0028] <Examples 1-37, Comparative Examples 1, 2> According to the formulations shown in Table 1, monomers (A), (B), (C), and an initiator were mixed and then heated and dissolved in a 60°C oven for 30 minutes, followed by dispersive stirring. Subsequently, an ultraviolet absorber, a light stabilizer, and additives were added and dispersed and stirred to produce the circuit protection active energy ray curable compositions S1 to S39.

[0029] The raw materials used in Table 1 are as follows: (Monomer (A)) • Shiko UV3520AC: Manufactured by Mitsubishi Chemical Corporation, urethane acrylate (2 functional groups, 30% by mass of the component is acrylic morpholine (ACMO)) • KRM7735: Urethane acrylate manufactured by Daicel Ornex Co., Ltd. (2 functional groups, 30% by mass of the component is acrylic morpholine (ACMO)) In Tables 1 and 2, the mass of urethane acrylate is listed as the mass of monomer (A), and the mass of ACMO is listed as the mass of monomer (C). (Monomer (B)) • Bisphenol A diglycidyl ether acrylic acid adduct: Bisphenol A type epoxy acrylate EBECRYL600: Manufactured by Daicel Ornex Co., Ltd., bisphenol A type epoxy acrylate. (Monomer(C)) • ACMO: Acrylic Morpholine LA: Lauryl acrylate CBA: Ethyl carbitol acrylate BZA: Benzyl acrylate CHA: Cyclohexyl acrylate IBXA: Isobornyl acrylate • THFA: Tetrahydrofurfurylacrylate • 4HBA: 4-hydroxybutyl acrylate • HDDA: 1,6-Hexanediol acrylate TMPTA: Trimethylolpropane triacrylate • PETA: Pentaerythritol tetraacrylate • DPHA: Dipentaerythritol hexaacrylate (Photopolymerization initiator) • Omnirad 1173: Manufactured by IGM Resins BV, 2-hydroxy-2-methylpropiophenone • Omnirad 379EG: Manufactured by IGM Resins BV, 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholinophenyl)butan-1-one (UV absorber) • Tinuvin 400: A hydroxyphenyltriazine-based UV absorber manufactured by BASF. • Tinuvin 477: A hydroxyphenyltriazine-based UV absorber manufactured by BASF. (Light stabilizer) • Tinuvin249: Hindered amine light stabilizer (Additives) TEGO Rad 2500: Fully crosslinkable silicon acrylate

[0030] [Manufacturing of laminates] A PET (125 μm thick) substrate was used. A conductive layer was formed on this substrate layer by screen printing PEDOT / PSS, and then a circuit was formed using silver paste. On these conductive layers, the circuit protection active energy ray curable compositions S1 to S37 were screen printed to a thickness of 30 μm, and then heated with a metal halide lamp (120 W / cm²). 3 The laminate was cured using a rate of 10 m / min.

[0031] [Evaluation of adhesion] The adhesion of the circuit protection layer to the conductive layer was evaluated based on JIS K5600-5-6:1999. The evaluation was based on the percentage of delamination squares. The evaluation criteria were as follows, with a score of 3 or higher indicating a practical level. The results are shown in Table 1. 6: No peeling is observed at all. 5: Peeling is less than 5% 4: Peeling is 5% or more but less than 15% 3: Peeling is 15% or more but less than 35% 2: Peeling is 35% or more but less than 50% 1: More than 50% peeling

[0032] [Evaluation of flexural resistance] After bending the laminated material 180°, the occurrence of cracks at the bend was evaluated by microscopic observation. The evaluation criteria were as follows, with a score of 3 or higher indicating a practical level. The results are shown in Table 1. No cracks were found after bending at 5:30. 4:25 After diffraction and bending, a crack occurs. 3:20 After bending, a crack appears. 2:15 After bending, a crack appears. 1:10 After bending, cracks appear.

[0033] [Table 1]

[0034] [Table 1]

[0035] [Table 1]

Claims

1. An active energy ray curable composition for circuit protection, comprising a urethane (meth)acrylate monomer (A) and a bisphenol-type epoxy (meth)acrylate monomer (B), The content of the monomer (A) is 20 to 40% by mass of the entire composition. The content of the monomer (B) is 5 to 30% by mass of the entire composition, and An active energy ray curable composition for circuit protection, characterized in that the mass ratio (A):(B) of monomer (A) to monomer (B) is 1.3:1 to 5:

1.

2. Furthermore, the active energy ray curable composition for circuit protection according to claim 1, further comprising a (meth)acrylate monomer (C) other than urethane (meth)acrylate monomer (A) and bisphenol-type epoxy (meth)acrylate monomer (B).

3. The active energy ray curable composition according to claim 2, wherein the (meth)acrylic monomer (C) other than urethane (meth)acrylate monomer (A) and bisphenol-type epoxy (meth)acrylate monomer (B) is a monofunctional monomer.

4. Furthermore, the circuit protection active energy ray curable composition according to claim 1 further contains an ultraviolet absorber, a light stabilizer, and a photopolymerization initiator.

5. A laminate comprising a substrate, a conductive circuit, and a protective layer made of an active energy ray curable composition for circuit protection according to any one of claims 1 to 4.

6. The laminate according to claim 5, wherein the conductive circuit includes a conductive polymer.

7. The laminate according to claim 5, wherein the base material is a flexible base material.

8. A substrate having a conductive circuit contains a urethane (meth)acrylate monomer (A) and a bisphenol-type epoxy (meth)acrylate monomer (B), The content of the monomer (A) is 20 to 40% by mass of the entire composition. The content of the monomer (B) is 5 to 30% by mass of the entire composition, and A circuit protection active energy ray curable composition is coated or printed, wherein the mass ratio (A):(B) of monomer (A) to monomer (B) is 1.3:1 to 5:

1. A method for manufacturing laminates, in which a protective layer is formed by curing with active energy rays.

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