KR20140122020A

KR20140122020A - Coverlay film and copper-clad laminate using the same

Info

Publication number: KR20140122020A
Application number: KR20130038515A
Authority: KR
Inventors: 신이치 하세가와; 요시에 콘도우; 사토시 마츠이; 시게키 요시다
Original assignee: 가부시키가이샤 아리사와 세이사쿠쇼
Priority date: 2013-04-09
Filing date: 2013-04-09
Publication date: 2014-10-17
Also published as: KR102016983B1

Abstract

The present invention provides a coverlay film and a copper-clad laminate using the same, wherein the coverlay film has improved transparency and heat resistance and significantly suppresses white turbidity due to bleed out of an oligomer component in a high temperature environment. The coverlay film includes a transparent film layer having a first surface and a second surface, a hard coat layer, and an adhesive layer. The hard coat layer is laminated on the first surface of the transparent film layer. The adhesive layer is laminated on the second surface of the transparent film layer. The total light transmittance of the coverlay film is 85% or more.

Description

TECHNICAL FIELD [0001] The present invention relates to a coverlay film and a copper clad laminate,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates generally to a coverlay film and a copper clad laminate used in a flexible printed wiring board.

The polyimide film has many characteristics required for electronic materials such as high heat resistance and high strength and is widely used in the field of a flexible printed wiring board (hereinafter, abbreviated as "FPC"). In the field of FPC, for example, there is a demand to use a material which is permeable to the FPC itself and to transmit light efficiently in cosmetic applications requiring high designability. Specifically, a case where a transparent FPC is used for a cellular phone is exemplified. However, the film using polyimide (PI) is yellow in color itself, so that it is difficult to satisfy the above requirement.

In order to satisfy the above-mentioned required characteristics, there has been developed a film using a colorless transparent film such as a polyethylene terephthalate (PET) film or a polyethylene naphthalate (PEN) film. For example, Patent Document 1 discloses a flexible substrate formed using PET or PEN as a plastic film.

(Prior art document)

(Patent Document 1) JP-A-5-259591

However, since the film made of PET or PEN has poor heat resistance and strength as compared with PI, it is deformed by heat in high temperature drying and solder reflow treatment in the manufacturing process, and defects may occur in some cases. In addition, when a PET film is used, clouding occurs due to bleed-out of the oligomer component, and transparency may be impaired.

In view of the above circumstances, it is an object of the present invention to provide a coverlay film having excellent transparency and heat resistance, markedly inhibited from clouding due to bleeding out of an oligomer component under a high temperature environment, and a copper clad laminate using the same .

Means for Solving the Problems As a result of intensive studies in order to solve the above problems, the present inventors have found that the above problems can be solved by providing a hard coat layer on a transparent film included in a coverlay film.

That is, the present invention is as follows.

[1] A coverlay film comprising a transparent film layer having a first side and a second side, a hard coat layer, and an adhesive layer,

Wherein the hard coat layer is laminated on the first surface of the transparent film layer, the adhesive layer is laminated on the second surface of the transparent film layer, and the total light transmittance is 85% or more.

[2] The transparent film layer described in [1], wherein the transparent film layer comprises at least one resin selected from the group consisting of a polyethylene terephthalate resin, a polybutylene terephthalate resin, a polyethylene naphthalate resin and a polycarbonate resin. .

[3] The coverlay film according to [1] or [2], wherein the thickness of the transparent film layer is 10 to 200 μm.

[4] The coverlay film according to any one of [1] to [3], wherein the hard coat layer is formed of a resin composition containing any one or more kinds of a theme selected from the group consisting of acrylate-based photosensitive compounds.

[5] The coverlay film according to any one of [1] to [4], wherein the hard coat layer has a thickness of 0.5 to 5 μm.

[6] The coverlay film according to any one of [1] to [5], wherein the glass transition temperature of the hard coat layer is higher than the glass transition temperature of the transparent film layer.

[7] The coverlay film according to any one of [1] to [6], wherein the hard coat layer has a glass transition temperature of 200 to 400 캜 and the glass transition temperature of the transparent film layer is 50 to 180 캜.

[8] The coverlay film according to any one of [1] to [7], wherein the adhesive layer comprises at least one resin selected from the group consisting of an acrylic resin, a urethane resin and a polyester resin.

[9] The coverlay film according to any one of [1] to [8], wherein the thickness of the adhesive layer is 10 to 50 μm.

[10] The coverlay film according to any one of [1] to [9], wherein the adhesive layer has a melt viscosity in the range of 100 ° C to 160 ° C of 100 to 100,000 poise.

[11] The adhesive layer according to any one of [1] to [9], wherein the copper foil layer is further laminated on a surface opposite to the surface on which the transparent film layer is laminated, Laminates.

[12] The copper clad laminate according to the above [11], wherein the adhesive layer has a melt viscosity in a range of 100 ° C to 160 ° C of 10,000 poise or more.

[13] A flexible printed wiring board comprising the coverlay film according to any one of [1] to [10] and the copper-clad laminate according to [11] or [12]

A circuit is formed on the copper foil layer included in the copper clad laminate, and then an adhesive layer of the coverlay film is adhered to the circuit formation face of the copper clad laminate.

[14] The flexible printed wiring board according to the above [13], wherein the difference in refractive index between the adhesive contained in the coverlay film and the adhesive contained in the copper clad laminate is 0 to 0.1.

(Effects of the Invention)

According to the present invention, it is possible to provide a coverlay film having excellent transparency and heat resistance and markedly suppressed whitening due to bleeding out of an oligomer component under a high temperature environment, and a copper clad laminate using the same.

Fig. 1 shows an example of a cross-sectional view of a coverlay film in the present embodiment.
2 shows an example of a cross-sectional view of the copper-clad laminate according to the present embodiment.
Fig. 3 shows an example of a cross-sectional view of a flexible printed wiring board according to the present embodiment.

Hereinafter, the mode for carrying out the present invention (hereinafter referred to as " present embodiment ") will be described in detail. The present invention is not limited to the following embodiments, and various modifications may be made within the scope of the present invention.

[Cover Ray Film]

The coverlay film in the present embodiment

A coverlay film comprising a transparent film layer having a first side and a second side, a hard coat layer, and an adhesive layer,

The hard coat layer is laminated on the first surface of the transparent film layer, the adhesive layer is laminated on the second surface of the transparent film layer, and the total light transmittance is 85% or more.

1, the coverlay film 10 according to the present embodiment has a structure in which a hard coat layer 1 is laminated on one side of a transparent film layer 2 and an adhesive layer 3 is laminated on the other side . The coverlay film in the present embodiment is set to have a total light transmittance of 85% or more of the entire coverlay film and is excellent in transparency and therefore is mainly used in skeleton (transparent) electronic devices and devices requiring high designability It can be preferably used as an FPC member. The total light transmittance of the coverlay film in the present embodiment is preferably at least 86%, more preferably at least 88%. When the coverlay film is provided with a separate film, the total light transmittance is measured with respect to the coverlay film with the separate film being peeled off. Hereinafter, each layer will be described.

[Transparent film layer]

The transparent film layer has a role to protect circuits formed on the wiring board when the coverlay film is used as a member of the flexible printed wiring board. The resin constituting the transparency film layer is not particularly limited as long as it is a transparent resin. For example, the resin constituting the transparency film layer may be a transparent resin such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN) and polycarbonate resin One or more resins selected are listed. Of these, PET is preferable from the viewpoint of cost and transparency.

The thickness of the transparent film layer is preferably 10 to 200 mu m, more preferably 25 to 100 mu m. When the thickness of the transparent film layer is 10 mu m or more, the protective effect of a circuit or the like tends to be good. When the thickness is 200 mu m or less, transparency tends to be improved and bendability also becomes good.

[Hard coat layer]

By providing the hard coat layer on the transparent film layer in the coverlay film in the present embodiment, the thermal and mechanical effects exerted on the transparent film layer can be minimized. As a result, the heat resistance of the coverlay film is improved, and the heat distortion starting temperature can be raised. In addition, it is possible to suppress the dimensional change in a high-temperature environment during the manufacturing process. Specifically, the PET film, which is one of the transparent films, has a property of shrinking in the longitudinal direction (MD) if it exceeds 100 DEG C, but it can be reduced by providing a hard coat layer.

Further, by providing a hard coat layer, the bleed-out of the oligomer contained in the transparent film layer can be suppressed. Generally, when the PET film is allowed to stand in a high temperature environment of 100 占 폚 or more, clouding occurs, but the hard coat layer can suppress it by physically blocking it.

Further, by providing a hard coat layer, the scratch resistance of the coverlay film can be improved. Normally, the PET film is about 2B in pencil hardness, but hardness is improved to HB by providing a hard coat layer. This makes it possible to suppress flaws which are likely to occur in the FPC processing step such as copper foil etching and CL press.

As described above, the coverlay film according to the present embodiment has a hard coat layer provided on the transparent film layer so that excellent heat resistance can be imparted. In addition, it is possible to suppress the bleed-out of the oligomer under a high temperature environment, It is excellent in transparency and designability.

The hard coat layer is made of a resin composition containing at least one main agent selected from the group consisting of an acrylate-based photosensitive compound.

Examples of the acrylate-based photosensitive compound include polytetramethylene glycol di (meth) acrylate, ethoxylated 2-methyl-1,3-propanediol di (meth) acrylate, 1,6-hexanediol di (Meth) acrylate, 1,10-decanediol di (meth) acrylate, 1,6-octanediol di (meth) acrylate, (Meth) acrylate, ethoxylated glycerin tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, , Ethoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, ethoxylated pentaerythritol tetra (meth) acrylate, propoxylated pentaerythritol tetra (meth) (Meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like. The acrylate-based photosensitive compound preferably has a weight-average molecular weight of preferably 150 to 3000, more preferably 150 to 2000, and more preferably has two or more (meth) acrylic groups as a functional group in that good UV sensitivity can be obtained , More preferably four or more.

In addition to the above-mentioned subject matter, the hard coat layer is formed from a resin composition containing a polymerization initiator and other additives. The polymerization initiator can be mainly divided into a photo radical polymerization initiator and a thermal radical polymerization initiator that generates radicals by heat.

As the photo radical polymerization initiator, for example, compounds such as triazine, benzoin, acetophenone, imidazole, xanthone or oxime ester can be used. Specific examples include 2,4-bistricloromethyl-6-p-methoxystyryl-s-triazine, 2-p-methoxystyryl-4,6-bisttrichloromethyl- 4-trichloromethyl-4-methylnaphthyl-6-triazine, benzophenone, p- (diethylamino) benzophenone, 2,2-dichloro- - phenoxyacetophenone, 2,2-diethoxyacetophenone, 2-dodecylthioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, 2,2- Irgacure 651, Irgacure 907, Darocur TPO, Irgacure 819, OXE-01, < RTI ID = 0.0 & OXE-02, ADEKA CORPORATION's N-1919, and NCI-831. These compounds may be used alone or in combination of two or more.

As thermal radical polymerization initiators, diazo compounds and peroxide compounds can be used. Specific examples include TOKYO CHEMICAL INDUSTRY CO., LTD. Azobisisobutyronitrile, manufactured by NOF Corporation, and Kniper BW manufactured by NOF Corporation. These compounds may be used alone or in combination of two or more.

Examples of other additives include antioxidants such as hindered phenol-based, phosphorus-based, and sulfur-based antioxidants; Stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; Flame retardants such as tris (dibromopropyl) phosphate, triaryl phosphate, and antimony oxide; Anionic, cationic and nonionic surfactants; An antistatic agent; Resin modifiers such as organic fillers and inorganic fillers; Organic fillers; Inorganic fillers; Plasticizers; Lubricants and the like can be used. The amount of the additive to be blended can be appropriately adjusted according to the purpose, without impairing the effect of the invention.

The thickness of the hard coat layer is preferably 0.5 to 5 占 퐉, more preferably 0.8 to 2 占 퐉. If the thickness of the hard coat layer is 0.5 mu m or more, the effect of heat resistance tends to be better, and if it is 5 mu m or less, the bendability tends to be good.

The glass transition temperature of the hard coat layer is preferably higher than the glass transition temperature of the transparent film layer. The glass transition temperature of the hard coat layer is preferably 200 to 400 캜, more preferably 250 to 350 캜, and still more preferably 300 to 350 캜. If the glass transition temperature of the hard coat layer is 200 DEG C or higher, the effect of heat resistance tends to be better. If the glass transition temperature of the hard coat layer is 250 占 폚 or higher, sticking can be suppressed and the handling property tends to be improved. On the other hand, the glass transition temperature of the transparent film layer is preferably 50 to 180 占 폚, more preferably 80 to 160 占 폚, and still more preferably 80 to 110 占 폚.

[Adhesive layer]

The adhesive layer is a layer for adhering an adherend such as a circuit to the transparent film layer. The resin constituting the adhesive layer is not particularly limited as long as it has transparency, and examples thereof include one or more resins selected from the group consisting of an acrylic resin, a urethane resin, and a polyester resin. Above all, from the viewpoint of transparency, an acrylic resin or a polyester resin is preferable.

The acrylic resin refers to a polymer obtained by polymerizing (meth) acrylic acid alkyl ester or (meth) acrylic acid. The (meth) acrylic acid alkyl ester is not particularly limited and includes, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) (Meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate and 2-hydroxyethyl (methyl) acrylate.

The urethane-based resin is not particularly limited, and examples thereof include a solvent-soluble urethane resin obtained by polymerizing a polyester polyol and a polyisocyanate. The polyester polyol is not particularly limited, and examples thereof include those obtained by esterifying a polybasic acid and a polyhydric alcohol. For example, a compound having two or more hydroxyl groups in one molecule can be used.

The polybasic acid as a starting material for producing the polyester polyol is not particularly limited, and examples thereof include polycarboxylic acids having two or more carboxyl groups in one molecule. Examples of the polycarboxylic acid include aliphatic dibasic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid and dodecanedicarboxylic acid; Aromatic polybasic acids such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid and pyromellitic acid; And aliphatic polybasic acids such as butane tricarboxylic acid, tricarvalic acid and citric acid. In the present embodiment, only aliphatic dibasic acids may be used as the polybasic acid. However, aliphatic dibasic acids may be used as the main component and an aromatic polybasic acid or an aliphatic polybasic acid may be mixed with the aliphatic dibasic acid. These dibasic acids or polybasic acids may be used singly or in combination of two or more.

As the polyhydric alcohol as a starting material for producing polyester polyol, for example, a compound having two or more hydroxyl groups in one molecule such as a dihydric alcohol or a trihydric or higher polyhydric alcohol can be used. Specific examples of the dihydric alcohol include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2- Propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1 Methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol and the like, Specific examples of polyhydric alcohols include aliphatic glycols, glycerin, trimethylol propane, trimethylol ethane, and pentaerythritol. In the present embodiment, as the polyhydric alcohol, only a bivalent alcohol may be used, or a bivalent alcohol such as aliphatic glycol as a main component and a polyhydric alcohol having a consumption ratio may be used in combination as the polyhydric alcohol. Particularly, . These divalent alcohols or polyhydric alcohols may be used singly or in combination of two or more kinds. As the polyester polyol, a polyester polyol compound obtained by a ring-opening reaction of caprolactone may be used.

On the other hand, the polyisocyanate compound to be reacted with the polyester polyol is a compound having two free isocyanate groups in one molecule. Specific examples thereof include hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate and trimethylene diisocyanate Aliphatic diisocyanates such as diisocyanate; Alicyclic diisocyanates such as isophorone diisocyanate, methylene bis (cyclohexyl isocyanate) and cyclohexane diisocyanate; Aromatic diisocyanates such as xylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate and biphenylene diisocyanate, and the like. These may be used singly or in combination of two or more.

In the reaction of the polyester polyol with the polyisocyanate compound, the reaction conditions for the usual urethanization reaction can be widely applied.

The polyester-based resin is not particularly limited, and examples thereof include those obtained by polycondensation of a carboxylic acid (dicarboxylic acid) and a polyalcohol (diol). Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, oxalic acid, succinic acid, succinic acid, adipic acid, azelaic acid, Butanedioic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,3-cyclohexane dicarboxylic acid, Cyclohexane dicarboxylic acid, 1,2-cyclohexane dicarboxylic acid, 2,5-norbornene dicarboxylic acid and its anhydride, tetrahydrophthalic acid and anhydrides thereof, and the like. If necessary, a small amount of 5-sodium sulfoisophthalic acid, 5-hydroxyisophthalic acid or the like may also be used as an acidic component within a range that does not impair the water resistance of the coating film. Among them, terephthalic acid is particularly preferable, and polybasic acid having three or more functionalities may be contained. Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl Butylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl- Triethylene glycol, dipropylene glycol and the like, and polyfunctional alcohol having three or more functionalities may be contained.

The polyester resin may further contain, if necessary, a fatty acid such as lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linoleic acid, or an ester forming derivative thereof, benzoic acid, p- High boiling monocarboxylic acids such as cyclohexanoic acid and 4-hydroxyphenylstearic acid, stearyl alcohol, high boiling monoalcohols such as 2-phenoxyethanol,? -Caprolactone, lactic acid,? -Hydroxylactic acid , p-hydroxybenzoic acid, and the like, or an ester-forming derivative thereof may be contained by copolymerization.

The method for producing the above resin is not particularly limited and can be produced by a conventionally known method.

The adhesive layer may be composed of a resin composition containing a curing agent, a curing accelerator, and other additives in addition to the resin. The curing agent and the curing accelerator are not particularly limited, and various known ones can be appropriately selected and used.

The curing agent is not particularly limited, and examples thereof include epoxy resins, isocyanate curing agents and imidazole curing agents. The blending amount of the curing agent is preferably 0.5 to 200 parts by mass, more preferably 5 to 80 parts by mass with respect to 100 parts by mass of the resin constituting the adhesive layer.

Examples of the epoxy resin include, but are not limited to, bisphenol A type epoxy resins, bisphenol F type epoxy resins, and bisphenol S type epoxy resins; Novolak type epoxy resins such as phenol novolak type epoxy resin and cresol novolak type epoxy resin; Biphenyl type epoxy resins; Naphthalene ring-containing epoxy resin; Alicyclic epoxy resins, and the like.

Examples of the isocyanate curing agent include, but are not limited to, TDI-TMP (tolylene diisocyanate-trimethylpropane adduct), HMDI-buret type, HMD I-isocyanurate, HMD I-TMP adduct Isocyanate-trimethylpropane-adduct), and XDI-TMP (xylylene diisocyanate-trimethylpropane adduct).

The imidazole-based curing agent is not particularly limited, and examples thereof include 2-methylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl- Imidazole compounds.

Examples of other additives include antioxidants such as hindered phenol-based, phosphorus-based, and sulfur-based antioxidants; Stabilizers such as light stabilizers, weather stabilizers, and heat stabilizers; Flame retardants such as tris (dibromopropyl) phosphate, triaryl phosphate, and antimony oxide; Anionic, cationic and nonionic surfactants; An antistatic agent; Resin modifiers such as organic fillers and inorganic fillers; Organic fillers; Inorganic fillers; Plasticizers; Lubricants and the like can be used. The blending amount of the additive can be appropriately adjusted according to the purpose as long as the effect of the present invention is not impaired.

The thickness of the adhesive layer included in the coverlay film is preferably 10 to 50 mu m, more preferably 15 to 30 mu m. When the thickness of the adhesive layer is 10 탆 or more, the adhesiveness between the transparent film layer and the adherend tends to be good, and when it is 50 탆 or less, the bendability tends to be good.

[Separation film layer]

In the adhesive layer included in the coverlay film in the present embodiment, a separate film layer may be further laminated on the surface opposite to the surface on which the transparent film layer is laminated. In the case of using a coverlay film having a separate film layer, after peeling the separate film layer, the adhesive layer side is adhered to the adherend. The resin for forming the separate film layer is not particularly limited and may be, for example, at least one selected from the group consisting of polyethylene terephthalate resin, polyethylene naphthalate resin, polypropylene resin, polyethylene resin and polybutylene terephthalate resin Among them, at least one resin selected from the group consisting of a polypropylene resin, a polyethylene resin and a polyethylene terephthalate resin is preferable from the viewpoint of reducing the manufacturing cost. The total light transmittance in this embodiment represents the total light transmittance of the entire coverlay film except for the separate film layer.

The thickness of the separate film layer is preferably 12 to 150 mu m, more preferably 25 to 75 mu m. When the thickness of the separate film layer is 12 μm or more, the separator film tends to be easily peeled off. When the thickness of the separator film is 150 μm or less, the adhesion to the transparent film layer tends to be stable.

The surface of the separate film layer on which the adhesive layer is laminated may be subjected to a releasing treatment. Since the release film is subjected to the release treatment, the release film can be easily peeled off from the transparent film, which improves handling properties of the coverlay film. The mold releasing treatment is not particularly limited, and for example, a releasing agent such as a silicone type releasing agent, a fluorine type releasing agent, a long chain alkyl graft polymer releasing agent and the like, or a method of surface treatment by plasma treatment can be used.

[Copper clad laminate]

Next, the copper clad laminate according to the present embodiment will be described.

The copper clad laminate according to the present embodiment is obtained by further laminating a copper foil layer on the surface opposite to the surface on which the transparent film layer is laminated in the adhesive layer included in the above-mentioned coverlay film. 2, the copper-clad laminate 20 of the present embodiment has a hard coat layer 1 laminated on one side of the transparent film layer 2 and an adhesive layer 3 'on the other side And a structure in which a copper foil layer 4 for forming a circuit is formed on the outside of the adhesive layer 3 'is further laminated.

The copper-clad laminate has the same structure as the coverlay film except that a copper foil layer for forming a circuit is further provided, but the cured state of the adhesive layer is different from that of the coverlay film. Concretely, the cured state of the adhesive layer included in the coverlay film is the B stage, while the cured state of the adhesive layer included in the copper clad laminate is the C stage. As described later, the coverlay film is bonded to the copper-clad laminate on which the circuit is formed, and then the adhesive layer is further cured to the C-stage. Herein, the term "B stage" means a melt viscosity of 100 to 100,000 poise, preferably 1,000 to 50,000 poise, more preferably 1,000 to 40,000 poise, in the range of 100 to 160 ° C, And has a melt viscosity of 10,000 poise or more, preferably 50,000 or more, and more preferably 100,000 poise or more in the range of -160 deg. The term " B stage " refers to a state in which the adhesive (layer) is melted and filled between circuits when heated to 100 DEG C or higher and pressurized to 0.5 MPa or higher, while the C stage means heating at 100 DEG C or higher and pressurization at 0.5 MPa or higher (Layer) is cured to such an extent that the adhesive (layer) does not melt. Further, the B stage and the C stage can not be clearly distinguished, and a part thereof overlaps.

The thickness of the adhesive layer included in the copper clad laminate is preferably 5 to 50 占 퐉, more preferably 10 to 25 占 퐉. When the thickness of the adhesive layer is 5 mu m or more, the adhesion between the transparent film layer and the adherend tends to be good, and when it is 50 mu m or less, the bendability tends to be good.

The total light transmittance of the copper clad laminate after removal of the copper foil layer (after etching the copper foil layer with an acid) is preferably 80% or more, more preferably 85% or more, still more preferably 88% or more.

[Flexible Printed Circuit Board]

The flexible printed wiring board according to the present embodiment includes the coverlay film and the copper clad laminate described above. After a circuit is formed on the copper foil layer included in the copper clad laminate, the adhesive layer of the coverlay film is laminated on the circuit formation face of the copper clad laminate .

3, the flexible printed wiring board 30 according to the present embodiment has a structure in which the circuit formed by the copper foil layer 4 passes through the adhesive layers 3 and 3 'from both sides of the transparent film layer 1 and the hard coat And a layer (2).

In the flexible printed wiring board according to the present embodiment, the difference in refractive index between the adhesive layer included in the coverlay film and the adhesive layer included in the copper clad laminate is preferably 0 to 0.1, more preferably 0 to 0.05. If the refractive index difference is within the above range, the transparency of the flexible printed wiring board tends to be further improved.

The total light transmittance of the flexible printed wiring board excluding the circuit portion is preferably 85% or more, and more preferably 88% or more.

The coverlay film, the copper clad laminate, and the flexible printed wiring board in the present embodiment may appropriately include other layers in addition to the above-described layers depending on the purpose.

[Manufacturing method]

The method for producing the coverlay film in the present embodiment is not particularly limited, and for example, it can be produced by a method having the following steps (a) and (b).

(a) a step of coating a varnish of a resin composition for forming a hard coat layer on one surface of a film constituting the transparency film layer, drying and UV curing the same,

(b) A step of applying a varnish of a resin composition for forming an adhesive layer on the surface of the transparent film layer opposite to the surface on which the hard coat layer is provided, and drying the varnish to the B-stage.

In the case where the coverlay film includes the separate film layer, it further includes, for example, the following step (c).

(c) a step of bringing the separate film into contact with the surface of the laminated film obtained in the step (b) on which the adhesive layer is provided.

As a manufacturing method of the copper clad laminate in this embodiment, for example, the following step (d) is further performed in addition to the above-mentioned steps (a) and (b).

(d) a step of laminating a copper foil on the surface of the laminated film obtained in the step (b) on which the adhesive layer is provided, and then drying the adhesive layer to the C-stage.

The flexible printed wiring board according to the present embodiment can be produced, for example, by the following step (e) using the coverlay film obtained above and the copper clad laminate.

(e) After a circuit is formed on the copper foil layer included in the copper clad laminate, the step of adhering the adhesive layer of the coverlay film to the circuit formation face of the copper clad laminate.

Examples of the solvent used in the varnish include acetone, toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, propylene glycol monomethyl ether, dimethylacetoamide and the like.

As a method of applying the varnish, a comma coater, a die coater, a gravure coater, or the like can be suitably employed depending on the coating thickness.

The drying of the varnish can be carried out by an in-line dryer or the like, and the drying conditions at that time can be suitably adjusted depending on the type and amount of the resin or the curing agent.

The UV curing is performed, for example, by a general UV irradiation amount such as a high-pressure mercury lamp. The UV irradiation amount can be appropriately adjusted depending on the kind and amount of the photosensitive compound and the polymerization initiator contained in the resin composition.

As a method of bonding the films to each other, a press method, a lamination method using a heat roll, or the like can be used. The bonding conditions may be, for example, a temperature of 40 to 120 DEG C and a pressure of 0.1 to 3 MPa.

Measurement and evaluation of physical properties in this specification can be carried out according to the methods described in the following examples, unless otherwise specified.

(Example)

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

In the examples and comparative examples, the measurement and evaluation of physical properties were carried out by the following methods.

(1) Thickness

And measured by a micrometer specified in JIS B 7502.

(2) Glass transition temperature

Rheometric Scientific, Inc. The dynamic viscoelasticity at the time of raising the temperature at 10 ° C / min was measured using a production dynamic viscoelasticity measuring device RSAII, and Tg was determined from the maximum value of tan delta.

(3) Melt viscosity

Using a Rheosol-G3000 manufactured by UBM Corporation, the sample was heated at a rate of 10 ° C / minute, and the dynamic viscosity ratio in the range of 100 ° C to 160 ° C was measured. Here, the dynamic viscosity ratio represents the viscosity when the shear vibration deformation of the rotating direction is applied to the sample. The melt viscosity represented by the examples and the like is the dynamic viscosity at 130 占 폚.

(4) Heat resistance (heat distortion temperature)

Japan Pulse Laboratories, Inc. The test was conducted using a production reflow soldering apparatus RF-630. As a sample, a flexible printed wiring board cut into 5 cm square was used. The sample was placed in a reflow apparatus, exposed at a predetermined temperature for one minute under far infrared rays, and judged from the warping state of the wiring board.

More specifically, after determining the warpage state of the sample when the reflow temperature was set at 100 占 폚, and then determining the warpage state of the sample at 110 占 폚, the warpage of each sample when the temperature was raised by 10 占 폚 A determination was made as to the state. In the judgment method, the treated sample was flat on a flat table, and the temperature of the reflow when the lifting of the end was 5 mm or more from the table was regarded as heat resistance (heat distortion temperature).

(5) Transparency (total light transmittance)

The total light transmittance was measured in accordance with JIS Z 8722. As a measuring instrument, Hitachi, Ltd. A spectrophotometer U-4100 manufactured by Toshiba Corporation was used.

(6) Intrinsic resistance (pencil hardness)

The scratch resistance was evaluated in accordance with the pencil hardness test, JIS K5600. Evaluation of the scratch resistance was performed on the surface of the hard coat layer in Examples, and on the surface of the transparent film layer in Comparative Examples.

(7) Dimensional change

Evaluation was carried out in accordance with 9.6 of JIS C 6471.

Specifically, the dimensional change rate was calculated by comparing the state immediately after removing the copper foil layer of the copper clad laminate with the state after heating at 140 占 폚 for 30 minutes and then at room temperature for 24 hours. The dimensional change was measured in the MD direction (longitudinal direction) of the sample.

(8) Bending property

A predetermined sample was bent by 180 DEG, and a bending test was carried out under which a load of 400 g / cm was applied. The sample was cut out from the flexible printed wiring board in a short direction with a length of 200 mm × 5 mm in the MD direction.

(9) Occurrence of bleed-out

The flexible printed wiring board was heated in an oven at 150 ° C for 1 hr, and the base value was measured in accordance with JIS K 7105. When the base value was 10 or more, it was judged that bleed-out occurred. As a measuring instrument, a Murakami Color Research Laboratory Co., Ltd. The HM-150 was used.

(10) Refractive index

The refractive index was measured in accordance with JIS K-7105. Abbe's refractometer was used as the measuring instrument. As a sample of the refractive index measurement, a resin film in the C-stage state (thickness: 20 mu m) produced from the resin composition for an adhesive for a coverlay film and a copper clad laminate was used.

[Resin composition for hard coat]

(Production Example 1)

5 parts by mass of methyl ethyl ketone, 5 parts by mass of a UV initiator (Chiba Specialty Chemicals, produced by KK, Darocure TPO) and 100 parts by mass of acrylic acrylate (produced by Daicel-Cytec Company Ltd., PETA-K) To obtain a resin composition 1 for hard coat.

(Production Example 2)

5 parts by mass of methyl ethyl ketone, 5 parts by mass of a UV initiator (Chiba Specialty Chemicals, KK, Darocure TPO), 50 parts by mass of acrylic acrylate (PETA-K, produced by Daicel-Cytec Company Ltd.) Acrylate (PEG400DA, manufactured by Daicel-Cytec Company Ltd.) was added and stirred at room temperature to obtain a hard coat resin composition 2.

[Resin composition for adhesive]

(Production Example 3)

The reaction vessel was charged with BA (butyl acrylate): MMA (methyl methacrylate): AA (acrylic acid) in a ratio of 75: 20: 5 (parts by mass), 100 parts by mass of ethyl acetate, (AIBN) (manufactured by TOKYO CHEMICAL INDUSTRY CO., LTD.) Were further added, and the mixture was stirred at 70 ° C for 10 hours, and polymerization reaction was carried out to obtain an acrylic polymer. Subsequently, 5 parts by mass of a bisphenol A type epoxy resin (product name: AER260, manufactured by Asahi Kasei Chemicals Corporation) was added to 100 parts by mass of the acrylic polymer, and the mixture was stirred at room temperature, and 50 parts by mass of methyl ethyl ketone was added until a predetermined viscosity To obtain a resin composition 1 for an adhesive.

(Production Example 4)

(Butyl acrylate): MMA (methyl methacrylate): AA (acrylic acid) was added to the reaction vessel at a ratio (mass part) of 60:30:10, and furthermore, 100 parts by mass of ethyl acetate, And 0.3 parts by mass of butyronitrile (AIBN) (manufactured by TOKYO CHEMICAL INDUSTRY CO., LTD.) Were added, and the mixture was stirred at 70 캜 for 10 hours for polymerization reaction to obtain an acrylic polymer. Subsequently, 10 parts by mass of a bisphenol A type epoxy resin (AER260, manufactured by Asahi Kasei Chemicals Corporation) was added to 100 parts by mass of the acrylic polymer, and the mixture was stirred at room temperature, and 50 parts by mass of methyl ethyl ketone was added until a predetermined viscosity To obtain a resin composition 2 for an adhesive.

(Example 1)

Fabrication of coverlay film (CL)

The resin composition for hard coat 1 was dried on one side of a polyethylene terephthalate (PET) film (manufactured by TOYOBO CO., LTD., Trade name A4300, thickness 50 탆) forming a transparent film layer, By using a die coater, followed by drying at 1000 캜 for 2 minutes, followed by UV curing with a high-pressure mercury lamp, thereby forming a hard coat layer on the polyethylene terephthalate film.

Subsequently, the resin composition for adhesive 1 was coated on the surface opposite to the surface provided with the hard coat layer of the polyethylene terephthalate film using a die cutter so that the thickness after drying became 25 占 퐉, and dried at 120 占 폚 for 2 minutes The adhesive layer was cured to the B-stage to obtain a coverlay film.

Further, the release surface of the separator film subjected to the releasing treatment was adhered to the adhesive-coated surface by means of a laminate.

Each evaluation of the obtained coverlay film was carried out, and the results are shown in Table 1.

Fabrication of copper clad laminate (CCL)

In the PET film provided with the hard coat layer obtained in Example 1, the resin composition for adhesive 2 was coated on the surface opposite to the surface provided with the hard coat layer using a die coater so that the thickness after drying was 10 占 퐉 Thereafter, the film was dried at 120 DEG C for 2 minutes, and an adhesive layer was formed on the polyethylene terephthalate film.

Next, the mat surface of the copper foil was laminated on the adhesive application side using a heat roll at 60 캜. Further, the laminated film in which the copper foil was laminated was heat-treated at 100 DEG C for 48 hours to cure the adhesive layer to the C-stage to obtain a copper clad laminate.

Each evaluation of the obtained copper clad laminate was carried out, and the results are shown in Table 1.

Fabrication of Flexible Printed Circuit Board (CL / CCL)

A predetermined circuit pattern was formed on the copper foil layer of the copper clad laminate obtained in Example 2. [ Then, the separator film was peeled off from the coverlay film obtained in Example 1, and the surface on which the circuit pattern of the copper clad laminate was formed and the surface on which the adhesive layer of the coverlay film was provided were bonded to each other and pressed under the conditions of 120 캜 x 3 MPa x 60 Thereby obtaining a flexible printed wiring board.

Each evaluation of the obtained flexible printed wiring board was carried out, and the results are shown in Table 1.

(Example 2)

A coverlay film, a copper clad laminate, and a flexible printed wiring board were produced in the same manner as in Example 1, except that the thickness of the hard coat layer was changed from 1 탆 to 6 탆, and evaluation was carried out.

(Example 3)

A coverlay film, a copper clad laminate, and a flexible printed wiring board were produced in the same manner as in Example 1 except that the resin composition 2 for hard coat was used, and the evaluation was carried out. The results are shown in Table 1.

(Example 4)

A coverlay film, a copper clad laminate, and a flexible printed wiring board were produced in the same manner as in Example 1, except that the thickness of the hard coat layer was changed from 1 탆 to 0.3 탆, and evaluation was carried out.

(Comparative Example 1)

A coverlay film, a copper clad laminate, and a flexible printed wiring board were produced in the same manner as in Example 1, except that the hard coat layer was not provided, and the evaluation was carried out. The results are shown in Table 1.

(Industrial applicability)

According to the present invention, it is possible to provide a coverlay film having excellent transparency and heat resistance and markedly inhibited from being clouded by bleeding out of an oligomer component under a high temperature environment, and a copper clad laminate using the same.

Claims

A coverlay film comprising a transparent film layer having a first side and a second side, a hard coat layer, and an adhesive layer,
Wherein the hard coat layer is laminated on the first surface of the transparent film layer, the adhesive layer is laminated on the second surface of the transparent film layer, and the total light transmittance is 85% or more. .

The method according to claim 1,
Wherein the transparent film layer comprises at least one resin selected from the group consisting of a polyethylene terephthalate resin, a polybutylene terephthalate resin, a polyethylene naphthalate resin and a polycarbonate resin.

3. The method according to claim 1 or 2,
Wherein the thickness of the transparent film layer is 10 to 200 占 퐉.

4. The method according to any one of claims 1 to 3,
Wherein the hard coat layer is made of a resin composition containing any one or more kinds of themes selected from the group consisting of an acrylate-based photosensitive compound.

5. The method according to any one of claims 1 to 4,
Wherein the hard coat layer has a thickness of 0.5 to 5 占 퐉.

6. The method according to any one of claims 1 to 5,
Wherein the hard coat layer has a glass transition temperature higher than the glass transition temperature of the transparent film layer.

7. The method according to any one of claims 1 to 6,
Wherein the hard coat layer has a glass transition temperature of 200 to 400 캜, and the transparent film layer has a glass transition temperature of 50 to 180 캜.

8. The method according to any one of claims 1 to 7,
Wherein the adhesive layer comprises one or more resins selected from the group consisting of an acrylic resin, a urethane resin, and a polyester resin.

9. The method according to any one of claims 1 to 8,
Wherein the thickness of the adhesive layer is 10 to 50 占 퐉.

10. The method according to any one of claims 1 to 9,
Wherein the adhesive layer has a melt viscosity of 100 to 100,000 poise in the range of 100 占 폚 to 160 占 폚.

The adhesive layer according to any one of claims 1 to 9, wherein a copper foil layer is further laminated on a surface of the adhesive layer opposite to the surface on which the transparent film layer is laminated Copper clad laminate.

12. The method of claim 11,
Wherein the adhesive layer has a melt viscosity of 10,000 poise or more in the range of 100 占 폚 to 160 占 폚.

11. A flexible printed wiring board comprising the coverlay film according to any one of claims 1 to 10 and the copper clad laminate according to claim 11 or 12,
Wherein a circuit is formed on the copper foil layer included in the copper clad laminate, and then an adhesive layer of the coverlay film is adhered to the circuit formation face of the copper clad laminate.

14. The method of claim 13,
Wherein the difference in refractive index between the adhesive contained in the coverlay film and the adhesive contained in the copper clad laminate is 0 to 0.1.