KR20150048104A - Connector and flexible wiring board - Google Patents

Abstract

An insertion-side connector inserted into a mating connector and used for connecting wiring.
The connector includes a flexible substrate, a wiring terminal disposed on one side of the flexible substrate, and a flexible substrate disposed on an end of the flexible substrate opposite to the wiring terminal of the flexible substrate, And a resin layer containing a resin.
The front end of the connector of the resin layer has a surface forming a convex curved surface that curves from the opposite surface toward the flexible substrate.

Description

CONNECTOR AND FLEXIBLE WIRING BOARD}

The present invention relates to a connector and a flexible wiring board.

2. Description of the Related Art Conventionally, various printed wiring boards of single-sided, double-sided or multi-layer have been widely used in the field of industrial equipment or consumer electronics. In an electronic device, only one printed wiring board is rarely used. For example, a plurality of printed wiring boards divided into functional units are used. Normally, a plurality of wiring boards are connected by various connectors.

The flexible wiring board is composed of a base material such as polyimide, a conductor material, an adhesive, and a coverlay as basic materials. Recently, the flexible wiring board has been assembled into a cellular phone, a video camera and a notebook computer . Generally, the flexible wiring board is mounted with a reinforcing member (reinforcing plate) attached to a mounting portion and a connector portion of an electronic component (for example, Patent Document 1).

As the reinforcing plate of the flexible wiring board, a metal plate such as a polyester film, a stainless plate and an aluminum plate, a ceramic, and a glass cloth based epoxy resin laminated plate are used. However, the thick polyimide film excellent in punching workability, heat resistance (heat resistance) and workability is the mainstream of the reinforcing plate of the connector. The reinforcing plate is bonded to the substrate on the opposite surface side with the wiring terminal disposed on one side of the substrate with an adhesive interposed therebetween (for example, refer to Non-Patent Document 1).

Patent Document 1: JP-A-2005-51177

Non-Patent Document 1: Electronic Materials, October 2004

However, in the connector described in Patent Document 1 and Non-Patent Document 1, in which a polyethylene terephthalate film or a polyimide film is used as a reinforcing plate, insertion into the mating connector may not be smoothly performed.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a connector having a smooth insertion property and a flexible wiring board having the connector.

The present invention relates to an insertion-side connector used for connecting a wiring inserted into a mating connector. A connector according to the present invention comprises a flexible substrate (flexible substrate), a wiring terminal disposed on one side of the flexible substrate, and a wiring terminal disposed on the end of the flexible substrate on the side opposite to the wiring terminal of the flexible substrate And a resin layer including a resin, the resin layer having a facing surface opposed to the flexible substrate. The front end of the connector of the resin layer may have a surface forming a convex curved surface that curves from the opposite surface toward the flexible substrate.

Since the front end of the connector of the resin layer has a surface forming a convex curved surface that curves toward the flexible substrate from the opposed surface opposed to the flexible substrate when the connector is inserted into the mating connector So that the insertability is sufficiently smooth.

The resin layer may further include an inorganic (inorganic) filler. The inorganic filler may be, for example, silica particles. The content of the inorganic filler in the resin layer may be 30 to 70% by volume with respect to the volume of the resin layer.

The flexible substrate may be a polyester substrate or a polyimide substrate. The thickness of the flexible substrate may be 75 mu m or less.

The initial tensile modulus of elasticity of the resin layer at 25 캜 may be 0.3 to 3.0 kPa. The thickness of the resin layer may be 50 to 500 mu m.

The present invention also relates to a flexible wiring board comprising the connector, the flexible substrate for circuit, and the circuit provided on the flexible substrate for circuit and connected to the wiring terminal of the connector. The flexible substrate of the connector and the flexible substrate for the circuit may be the same substrate, and the flexible substrate of the connector may be connected to another flexible substrate for the circuit.

According to the present invention, it is possible to provide a connector having a smooth insertion property and a flexible wiring board having the same.

1 is a schematic view showing an embodiment of a connector.
2 is a sectional view of the connector shown in Fig. 1 taken along the line II-II '; Fig.
Fig. 3 is a cross-sectional view (end view) showing a modified example of the shape of the resin layer.
[Fig. 4] is a cross-sectional view (end view) showing another embodiment of the connector.
5 is a sectional view (end view) showing another embodiment of the connector.
6 is a cross-sectional view (end view) showing another embodiment of the connector.
7 is a process diagram showing one embodiment of a method for manufacturing a connector.
8 is a schematic explanatory view showing a durability test method of a connector.
9 is an optical microscope photograph of a cross section of a connector.
10 is a scanning electron micrograph of a cross section of the resin layer.

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. All the constitutions described in this specification can be arbitrarily combined within a range not deviating from the gist of the present invention. For example, a numerical range relating to various characteristics can be defined by using, as an upper limit value or a lower limit value, a numerical value arbitrarily selected from numerical values described in the upper and lower limits of the numerical range described in this specification, and numerical values described in the embodiment.

1 is a schematic view showing an embodiment of a connector. 2 is a cross-sectional view taken along line II-II 'in Fig. The connector 10 shown in Figs. 1 and 2 includes a flexible substrate 2, a wiring terminal 1 disposed on one side of the flexible substrate 2, And a resin layer 3 disposed on the end of the flexible substrate 2 on the side opposite to the side of the substrate 1. The rigidity of the flexible base material 2 is higher at a portion in contact with the resin layer 3 as compared with the case where the resin layer 3 is not formed. The connector 10 is an insertion-side connector which is inserted into a mating connector and used for connecting wiring. By inserting the tip end of the connector 10 into the mating connector, a state can be obtained that can be transmitted, for example, by mechanical or electrical (electronic) connection. The connector 10 can be safely and easily removed as needed.

2, a circuit 51 provided on a flexible substrate 52 for a circuit and a flexible substrate 52 for a circuit is shown together with the connector 10. The circuit 51 is connected to the wiring terminal 1 of the connector 10. The flexible wiring board 100 is constituted by the connector 10, the flexible substrate 52 for circuit, and the circuit 51. The flexible substrate 2 of the connector and the flexible substrate 52 for the circuit may be the same one substrate or each substrate connected to each other.

The flexible base material 2 may be a polyester base material (polyester film) or a polyimide base material (polyimide film) from the viewpoint of toughness, although it is not particularly limited as long as it shows flexibility capable of bending , And may be a polyimide substrate (polyimide film) in view of toughness and heat resistance. The thickness of the flexible base material 2 may be 75 m or less in terms of bending property. The thickness of the flexible base material 2 may be 10 占 퐉 or more.

The wiring terminal 1 is, for example, a conductor layer formed of a conductor such as a metal. The thickness of the wiring terminal 1 may be 5 to 40 mu m.

The resin layer 3 usually contains a cured product (cured product) of the curable resin composition as a resin. Details of the curable resin composition used for forming the resin layer 3 will be described later.

The resin layer 3 has a facing surface 6 facing the flexible substrate 2 as a surface located on the opposite side of the surface in contact with the flexible substrate 2. The end 3a of the resin layer 3 on the front end side (the portion to be inserted into the mating connector) of the connector 10 is curved from the opposing face 6 toward the flexible base 2, And a surface 7 forming a convex curved surface convex toward the outside of the resin layer 3. Since the surface 7 of the end 3a of the resin layer 3 forms a convex surface, resistance at the time of insertion into the mating connector decreases, and smooth insertion property is obtained.

In the connector according to the present embodiment, the end portion of the resin layer 3 opposite to the front end of the connector 10 is also curved from the opposing face 6 toward the flexible base 2 to form a convex curved surface Lt; / RTI > However, the surface of the end portion on the opposite side of the tip of the connector 10 does not need to form a convex surface. The end of the resin layer 3 on the side of the connector 10 may have a surface curving from the opposing face 6 toward the flexible base 2 to form a convex curved surface .

The surface of the end 3a of the resin layer 3 (the surface of the portion not in contact with the flexible substrate 2) may have a convex surface in part or in whole. The end 3a of the resin layer 3 may have a surface that forms a plane along the normal line of the main surface of the flexible substrate as in the embodiment of Fig. 3 (a) and 3 (b) are cross-sectional views showing a modified example of the resin layer shape. In the embodiment shown in Fig. 3 (b), the entire side surface of the end portion of the connector at the end 3a of the resin layer 3 forms a convex surface.

The thickness of the resin layer 3 may be 50 to 500 mu m, 70 to 300 mu m, or 75 to 200 mu m. If the thickness of the resin layer 3 is within these ranges, the formation of the resin layer is easy. In addition, since the resin layer 3 is not easily bent, excellent shape retention of the connector is obtained. The length of the resin layer 3 in the insertion direction of the connector may be, for example, 3 to 30 mm. The resin layer 3 may be provided over the entire width direction of the flexible substrate, or may be provided only in a part of the width direction within a range in which required rigidity is obtained.

The initial tensile elastic modulus of the resin layer 3 at 25 캜 may be 0.3 to 3.0 kPa, 0.5 to 2.5 kPa, or 1.0 to 2.2 kPa. When the initial tensile modulus of elasticity of the resin layer 3 is within these ranges, cracking of the resin layer 3 is less likely to occur, and more excellent insertion property can be obtained.

The initial tensile modulus at 25 deg. C of the resin layer 3 can be obtained from the maximum value of the slope of the tangent line of the stress-displacement curve obtained when the tensile stress is applied to the rectangular resin layer at a tensile speed of 50 mm / min. The rectangular resin layer can be prepared, for example, by cutting it from a plate-like resin layer formed by curing a curable resin composition described later. The details of the method of measuring the initial tensile modulus are described in detail in Examples described later.

The initial tensile modulus in the above numerical range can be achieved, for example, by a resin layer containing an inorganic filler in addition to the resin.

The inorganic filler in the resin layer (3) may be composed of one kind of particles or a combination of two or more kinds of particles. The average particle diameter of the inorganic filler may be 1 to 100 占 퐉, 1 to 50 占 퐉, 1 to 20 占 퐉, or 1.5 to 10 占 퐉. The inorganic filler may be a mixture of plural kinds of fillers having different average particle diameters. Thereby, the space filling rate by the inorganic filler can be increased.

The average particle diameter of the inorganic filler is an arithmetic average of the particle diameters (maximum diameters) of the plurality of inorganic fillers observed by observing the resin layer 3 with a scanning electron microscope at, for example, a magnification of 1000 times . The number of inorganic fillers in which the particle size is measured to obtain the average particle size is, for example, 50 or more.

The content of the inorganic filler in the resin layer 3 is preferably 30 to 70% by volume, 40 to 65% by volume, or 50 to 65% by volume with respect to the volume of the resin layer 3 in terms of the strength of the resin layer and the initial tensile elastic modulus Volume%. The content of the inorganic filler in the resin layer 3 is preferably 40 to 85 mass%, 45 to 80 mass%, or 50 (mass%) based on the mass of the resin layer 3 in terms of the strength of the resin layer and the initial tensile modulus To 80% by mass.

The inorganic filler may contain silica particles. The silica particles are not particularly limited and may be, for example, spherical silica, crushed silica finely pulverized, dry silica or wet silica.

When the spherical silica particles are selected, the surface of the resin layer 3 becomes smooth, and smooth insertion property is obtained. Further, excellent abrasion resistance and crack resistance can be obtained.

The spherical silica particles can be obtained by, for example, a sol-gel method. The average particle diameter of the spherical silica particles may be 0.05 to 50 탆, 0.1 to 50 탆, 0.2 to 30 탆, or 0.5 to 20 탆.

The spherical silica particles need only have a nearly spherical shape (see JIS Z2500: 2000), and it is not always necessary to have a perfect spherical shape. The ratio DL / DS of the long diameter (DL) and the short diameter (DS) of the particles (sometimes referred to as spherical coefficient or sphericity) may be 1.0 to 1.2 .

Examples of the spherical silica particles include MSR-2212, MSR-SC3, MSR-SC4, MSR-3512 and MSR-FC208 (trade names, available from Tatsumori Kikai Co., SO-E2, SO-E3, SO-E5, SO-E6, SO-C1, SO-C2, SO-C3, SO-C5, SO- FB-950FC, FB-9504, FB-9504, FB-9504, FB-950, FB-5SDC, FB-3SDC (above, Denki Kagaku Co., Ltd., hereinafter referred to as " FB-5FDF " Trade name, manufactured by Takara Shuzo Co., Ltd.).

The silica particles may be surface-treated. The surface treatment agent used for surface treatment of the silica particles may be, for example, vinyltrimethoxysilane, vinyltriethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3- Glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, , p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri (Aminoethyl) -3-aminopropyltrimethoxysilane, n-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane triethoxysilane, N-2- (aminoethyl) -3-aminopropyltriethoxysilane, 3-aminov Aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane , Hydrochloride salt of N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane, 3-ureide propyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3- (3-isocyanatopropyltriethoxysilane, polycondensation product of dimethylsilane, polycondensation product of diphenylsilane, and condensation product of dimethylsilane and diphenylsilane), And one kind or two or more kinds selected from the group consisting of Of these, N-phenyl-3-aminopropyltrimethoxysilane can be selected from the viewpoint of compatibility with an acrylic resin.

The resin layer 3 may contain fumed silica as an inorganic filler. The fumed silica may be used to control the printability of a liquid composition to be described later which is used for forming the resin layer 3. Examples of commercially available fumed silica include hydrophilic silica such as Aerosil 50, 90G, 130, 200, 300 and 380 and hydrophilic silica such as R972, R972CF, R972V, R974, R9765, R140, RX50, NAX50, NX90G, RX200, RX300, R812 , R8200 and R200H (trade names, manufactured by Nippon Aerosil Co., Ltd.).

4 is a cross-sectional view showing another embodiment of the connector. The flexible substrate 2 of the connector 10 shown in Fig. 4 is composed of a flexible substrate 40 and a cover film 41 provided on the main surface of the flexible substrate 40 on the resin layer 3 side. The cover film 41 can serve as a film or a solder resist for protecting the wiring terminal 1, for example. The cover film 41 may be provided on the main surface of the flexible substrate 40 on the wiring terminal 1 side or may be provided on both surfaces of the flexible substrate 40. As the flexible substrate 40, the same substrate as the flexible substrate 2 can be used.

The cover film 41 can be formed using various thermosetting or photosensitive resin films. Examples of commercial products of the resin film used for forming the cover film 41 include Nikaflex CTSV, CISV, CISA, CKSE, CISG and CKSG (trade names, manufactured by Nikkan Kogyo Kabushiki Kaisha) FZ-2530G, FZ-2535G (manufactured by Hitachi Chemical Co., Ltd., trade name, manufactured by DuPont Co., Ltd.), Latec FR-7025, FR-7038, FR-7050, FZ-2520G, FZ- Trade name).

5 is a cross-sectional view showing another embodiment of the connector. 5 includes a flexible substrate 40 and a nonwiring metal layer 42 and a cover film 41 which are sequentially provided on the main surface on the side of the resin layer 3 of the flexible substrate 40 ). 6, the flexible substrate 2 is composed of the flexible substrate 40 and the non-wiring metal layer 42 provided on the main surface of the flexible substrate 40 on the resin layer 3 side, (41).

The connector 10 includes a step of providing the wiring terminal 1 on one side of the flexible substrate 2 and a step of forming the resin layer 2 on the side opposite to the wiring terminal 1 of the flexible substrate 2, (3). ≪ / RTI > The wiring terminals 1 may be provided before forming the resin layer 3 or after the resin layer 3 is formed.

The resin layer 3 can be formed by a method including, for example, a step of applying a liquid composition (liquid ink) containing a curable resin composition and, if necessary, an inorganic filler, to a flexible substrate . According to the method using such a liquid composition, a rigid resin layer can be formed by a simple process. The thickness of the resin layer can be easily and precisely controlled by a method such as printing. Therefore, products having different thickness specifications can be efficiently produced. Further, according to the method such as printing, the resin layer can be formed very efficiently at any position on the flexible substrate, without depending on manual operation. Further, a resin layer having excellent resistance to reflow can be formed.

Fig. 7 is a process chart showing one embodiment of a method of forming the resin layer 3 using the liquid composition 5. Fig. First, a liquid composition 5 containing a curable resin composition and a metal mask 4 having openings 4a are prepared (see Fig. 7 (a)). The liquid composition (5) may contain a solvent which dissolves or disperses the curable resin composition.

Next, the liquid composition 5 is filled in the opening 4a of the metal mask 4 and printed on the flexible substrate 2 (see Fig. 7 (b)). The method of applying the liquid composition can be appropriately selected from screen printing, bar coater, and the like in addition to printing using a metal mask.

The solvent is removed from the applied liquid composition 5 by a method such as heating if necessary to form an uncured resin layer 3 (see Fig. 7 (c)). By curing the curable resin composition in the uncured resin layer (3), a resin layer (3) containing the cured resin composition as a resin is formed. The curing of the curable resin composition can be performed, for example, by heating or light irradiation. The metal mask 4 can be removed, for example, after application of the curable resin composition. According to the method in which the liquid composition is applied and cured, a resin layer having an end portion having a convex curved surface can be easily formed.

The solvent removal (drying) and curing temperature may be 50 to 250 캜, 80 to 200 캜, or 100 to 190 캜.

For example, the resin layer 3 can be disposed on the end portion of the flexible substrate 2 by punching the flexible substrate 2 (see Fig. 7 (d)).

The liquid composition (5) may contain, for example, a curable resin composition, the above-described inorganic filler, and a solvent. The curable resin composition is composed of components other than the solvent and the inorganic filler in the liquid composition (5), and contains, for example, a curable resin that is cured by heat and / or light and a thermoplastic resin. The curable resin includes, for example, one or more kinds of epoxy resins. The thermoplastic resin includes, for example, one or more kinds of acrylic resins (polymers of acrylic monomers).

Examples of the epoxy resin include polyglycidyl esters obtained by reacting epichlorohydrin with polyhydric phenols such as bisphenol A, novolak type phenol resin and orthocresol novolak type phenol resin, or polyhydric alcohols such as 1,4-butanediol Polyglycidyl esters obtained by reacting epichlorohydrin with polybasic acids such as diethyl ether, phthalic acid and hexahydrophthalic acid, N-glycidyl derivatives of compounds having an amino group, amide group or heterocyclic nitrogen group, Type epoxy resin. A biphenyl aralkyl type epoxy resin can be selected because it has high compatibility with an acrylic resin.

The curable resin may contain an epoxy resin curing agent. The curing agent may be selected from polyfunctional phenols (phenol resins) such as dicyandiamide, diaminodiphenylmethane, diaminodiphenylsulfone, phthalic anhydride, pyromellitic anhydride, and phenol novolak and cresol novolac .

The phenol resin may include phenol type, bisphenol A type, cresol novolak type, or aminotriazine novolak type phenol resin. One or both of cresol novolak type and aminotriazine novolak type phenol resin can be selected from the viewpoint of compatibility with an acrylic resin. The aminotriazine novolak-type phenol resin has a structural unit represented by the following structural formula (I).

[In the formula (I), R represents a hydrogen atom or a methyl group, and n represents an integer of 1 to 30.]

The curable resin may contain a high molecular weight component for the purpose of improving the heat resistance of the resin layer. However, the molecular weight of the component constituting the curable resin is usually 3,000 or less.

The curable resin may contain an accelerator for the purpose of accelerating the curing reaction. The kind and blending amount of the promoter are not particularly limited. For example, one or two or more selected from an imidazole compound, an organic phosphorus compound, a tertiary amine, and a quaternary ammonium salt.

The acrylic resin is generally a copolymer containing, as a monomer unit, a polymerizable monomer comprising two or more kinds of acrylic monomers having an acryl group or a methacryl group. The acrylic resin can be produced inexpensively by selecting various combinations from commercially available acrylic monomers according to desired characteristics. Since the acrylic resin has good solubility in a ketone solvent having a low boiling point, the acrylic resin is excellent in that the printed liquid composition can be easily dried.

The acrylic monomer used for producing the acrylic resin is not particularly limited. The acrylic resin may be, for example, acrylonitrile, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, pentyl acrylate, , 2-ethylhexyl acrylate, n-octyl acrylate, dodecyl acrylate, octadecyl acrylate, butoxyethyl acrylate, phenyl acrylate, benzyl acrylate, naphthyl acrylate, cyclohexyl acrylate, isobornyl acrylate, tricyclo [5.2.1.O ^2,6] deca-8-yl (dicyclopentanyl acrylate) acrylate, tricyclo [5.2.1.O ^2,6] deca-4-methyl acrylate, adamantyl acrylate, Isobornyl acrylate, tricyclohexyl acrylate [5.2.1.o ^2,6 ] deca-8-yl, tricyclohexyl acrylate [5.2.1.o ^2,6 ] deca-4-methyl, and acrylic acid Adamantyl and the like, and esters of acrylic acid such as ethyl methacrylate, methacrylic acid n- Propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, pentyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, N-hexyl methacrylate, n-octyl methacrylate, octyldodecyl methacrylate, octadecyl methacrylate, octadecyl methacrylate, butoxyethyl methacrylate, phenyl methacrylate, naphthyl methacrylate, cyclopentyl methacrylate, cyclohexyl methacrylate, Methylcyclohexyl methacrylate, tricyclohexyl methacrylate, m-methacrylic acid norbornyl, methacrylic acid norbornyl methyl, methacrylic acid isobornyl, methacrylic acid carbonyl, menthyl methacrylate, adamantyl methacrylate, methacrylic acid bicyclo [5.2.1.O ^2,6] deca-8-yl (dicyclopentanyl methacrylate), and methacrylate, tricyclo [5.2.1.O ^2,6] deca-4, such as methyl methacrylate And an ester of an acrylic monomer as a monomer unit.

In view of heat resistance and adhesion of the resin layer according to the present embodiment, the acrylic monomer constituting the acrylic resin may include a monomer having a functional group. The monomer having a functional group may have at least one polymerizable carbon-carbon double bond and at least one functional group selected from the group consisting of a carboxyl group, a hydroxyl group, an acid anhydride group, an amino group, an amide group and an epoxy group . Specific examples of the monomer having a functional group include monomers containing a carboxyl group such as acrylic acid, methacrylic acid, and itaconic acid, monomers containing 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, Hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and N-methylol methacrylamide, (o-, m-, p-) hydroxystyrene, acid anhydride group-containing monomers such as maleic anhydride, Diethylaminoethyl methacrylate, and other amino group-containing monomers such as glycidyl acrylate, glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, acrylate-3,4-epoxybutyl acrylate Epoxybutyl acrylate, acrylic acid-6,7-epoxyheptyl methacrylate, 6,7-epoxyheptyl methacrylate, 3-methyl-4-epoxyacrylate Butyl-3-methyl-3,4-epoxybutyl methacrylate, 4-methyl-4,5-epoxypentyl acrylate, ? -Methyl glycidyl methacrylate,? -Methyl glycidyl methacrylate,? -Methyl glycidyl methacrylate,? -Methyl glycidyl methacrylate,? -Methyl glycidyl methacrylate,? -Methyl glycidyl methacrylate, Methyl-3,4-epoxybutyl acrylate, 3-methyl-3,4-epoxybutyl methacrylate, and 4-methyl-4,5-epoxypentyl acrylate , Epoxy methacrylate-4-methyl-4,5-epoxypentyl, acrylate-5-methyl, 6-epoxyhexyl, and methacrylic acid-5-methyl-5,6-epoxyhexyl. have. These may be used alone or in combination of two or more.

When the acrylic resin has a glycidyl group, the heat resistance of the resin layer becomes higher. Therefore, the acrylic resin may contain glycidyl methacrylate or glycidyl acrylate as a monomer unit. The content of glycidyl methacrylate or glycidyl acrylate is preferably 0.5 to 10% by mass, 1 to 8% by mass, or 2 to 5% by mass based on the amount of all the polymerizable monomers constituting the acrylic resin %.

The acrylic resin may contain an alkyl acrylate as a monomer in view of adhesion between the flexible substrate and the resin layer. The number of carbon atoms of the alkyl group of the alkyl acrylate may be 1 to 12 or 2 to 10. The content of the alkyl acrylate may be from 50 to 99% by mass, from 60 to 98% by mass, or from 70 to 96% by mass, based on the amount of all the polymerizable monomers constituting the acrylic resin. The alkyl acrylates are selected, for example, from ethyl acrylate and butyl acrylate.

The acrylic resin may contain acrylonitrile or methacrylonitrile as a monomer unit from the viewpoint of toughness and adhesiveness. The content of acrylonitrile or methacrylonitrile may be 0.5 to 10% by mass, 1 to 8% by mass, or 2 to 5% by mass based on the amount of all the polymerizable monomers constituting the acrylic resin.

The acrylic resin may further contain other monomers copolymerized with the acrylic monomer. Other monomers include, for example, 4-vinylpyridine, 2-vinylpyridine,? -Methylstyrene,? -Ethylstyrene,? -Fluorostyrene,? -Chlorostyrene,? -Bromostyrene, fluorostyrene, Aromatic vinyl compounds such as styrene, bromostyrene, methylstyrene, methoxystyrene and styrene, and aromatic vinyl compounds such as N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, Substituted maleimides such as N-methylmaleimide, N-butylmaleimide, Nt-butylmaleimide, N-laurylmaleimide, N-cyclohexylmaleimide, N-benzylmaleimide and N-phenylmaleimide At least one kind of compound.

The weight average molecular weight of the acrylic resin may be 150,000 to 1,800,000, 400,000 to 1,500,000, or 500,000 to 1,400,000. When the weight average molecular weight of the acrylic resin is 150,000 or more, the viscosity of the liquid composition is high and the liquid composition can exhibit thixotropy. When the weight average molecular weight of the acrylic resin is 1.8 million or less, the solubility in a solvent is improved, and it becomes easy to increase the concentration of solid content in the liquid composition. If the concentration of the solid content of the liquid composition is high, there is less need to consider the control of the film thickness of the applied liquid composition and the reduction of the film pressure due to drying shrinkage.

The glass transition temperature (Tg) of the acrylic resin may be -50 to 100 占 폚, -45 to 20 占 폚, or -40 占 to 5 占 폚. The Tg of an acrylic resin composed of n kinds of monomers can be calculated by the following equation (FOX formula).

Tg (℃) = {1 / (W 1 / Tg 1 + W 2 / Tg 2 + ... + W i / Tg i + ... + W n / Tg n)} - 273

In the FOX formula, Tg _i (K) represents the glass transition temperature of the homopolymer of each monomer, W _i represents the mass fraction of each monomer, and W ₁ + W ₂ + + W _i + ... W _n = 1.

For example, glass transition of an acrylic resin obtained by copolymerizing 5 mass% of glycidyl methacrylate, 5 mass% of acrylonitrile, 85 mass% of ethyl acrylate, and 5 mass% of butyl acrylate The temperature Tg is calculated as follows.

Tg = {1 / (0.05 / 319 + 0.05 / 498 + 0.85 / 251 + 0.05 / 219)} - 273 = -14.7 DEG C

Based on the total mass of the thermoplastic resin (for example, acrylic resin), the curable resin (for example, epoxy resin) and the curing agent (for example, phenol resin), the content ratio of the thermoplastic resin is 40 to 90 wt% To 85% by weight, or 60 to 80% by weight. At this time, the total amount of the glycidyl group of the acrylic resin and the epoxy group of the epoxy resin and the hydroxyl value of the phenol resin may be substantially equivalent.

The liquid composition (5) can be prepared, for example, by mixing each component constituting the curable resin composition with a solvent, if necessary, and stirring. When the liquid composition 5 contains an inorganic filler, the liquid composition may be prepared using a slurry obtained by dispersing an inorganic filler in an organic solvent containing a surface treatment agent in advance. Further, a mixture of the components of the curable resin composition containing the curable resin may be prepared in advance, and the mixture may be mixed with a slurry of the inorganic filler to obtain a liquid composition.

The solvent used for dissolving or dispersing the curable resin composition and the inorganic filler is selected from ketone solvents such as methyl ethyl ketone and cyclohexanone. From the viewpoint of printability, cyclohexanone can be selected.

Example

Hereinafter, the present invention will be described in more detail by way of examples. However, the present invention is not limited to these.

Production Example 1

3.0 g of N-phenyl-3-aminopropyltrimethoxysilane (KBM573, trade name, manufactured by Shin-Etsu Silicones Co., Ltd.) was dissolved in 129 g of cyclohexanone, and then adomorphine SO-25R (manufactured by Admatech Co., Ltd.) was added with stirring, the whole amount was added, and the mixture was further stirred at room temperature for 1 hour. 27.6 g of a cyclohexanone solution (solid content 50% by mass) of NC-3000H (trade name, manufactured by Nippon Kayaku) as an epoxy resin, 27.6 g of LA-3018 (trade name, manufactured by Dainippon Ink and Chemicals, 18.7 g of a methyl ether solution (solid content 60% by mass) and 0.42 g of 2-ethyl-4-methylimidazole (2E4MZ, trade name of Shikoku Chemicals) were added and stirred for 30 minutes, (Solid content: 24.9% by mass) of glycidyl methacrylate, acrylonitrile, ethyl acrylate and butyl acrylate copolymer (weight average molecular weight: 610,000, epoxy equivalent: 2869) Followed by stirring and mixing to obtain a liquid composition.

Production Examples 2 to 7

A liquid composition was obtained in the same manner as in Production Example 1, except that the respective materials shown in Tables 1 and 2 were used in the ratios shown in the tables. The mixing amounts of the acrylic resin, the epoxy resin, and the phenol resin shown in Tables 1 and 2 are based on the total amount of the acrylic resin, the epoxy resin and the phenol resin.

The weight average molecular weight of the acrylic resin was converted from a calibration curve using standard polystyrene by gel permeation chromatography (GPC). The calibration curve was approximated by a cubic equation using 5 sample sets of standard polystyrene (PStQuick MP-H, PStQuick B [trade name, manufactured by TOSO CORPORATION]). GPC conditions are shown below.

Apparatus: (pump: L-2130 model [manufactured by Hitachi High-Technologies Corporation]),

(Detector: L-2490 type RI (manufactured by Hitachi High-Technologies Corporation)),

(Column oven: L-2350 [manufactured by Hitachi High-Technologies Corporation])

Column: Gelpack GL-A100M (trade name, manufactured by Hitachi Chemical Co., Ltd.)

Column size: 10.7 mm ID 300 mm

Eluent: tetrahydrofuran

Sample concentration: 10 mg / 2 ml

Injection amount: 200 μl

Flow rate: 2.05 ml / min

Measuring temperature: 25 ° C

Details of each material shown in Table 1 and Table 2 are as follows.

1. Acrylic resin

GMA / AN / EA / BA: Copolymer of glycidyl methacrylate, acrylonitrile, ethyl acrylate and butyl acrylate

2. Epoxy resin

NC-3000H: biphenyl aralkyl type epoxy resin (trade name, epoxy equivalent 290, manufactured by Nippon Kayaku Co., Ltd.)

3. Phenolic resin

LA-3018: Aminotriazine novolac phenol resin (trade name, manufactured by Dainippon Ink and Chemicals, Inc., hydroxyl equivalent: 151, nitrogen content: 18%)

4. Silica particles

· F05-12: Fractured silica, product name of Fukushima Yoshinobu Co., Ltd.

· SO-25R: spherical silica, trade name made by ADOMATECH KK

5. Surface treatment agent (silane coupling agent)

KBM573: N-phenyl-3-aminopropyltrimethoxysilane, trade name of Shin-Etsu Silicone Co., Ltd.

(Mechanical Properties of Resin Layer)

A liquid composition was applied to a mold release PET (polyethylene terephthalate) film using a bar coater so that the thickness after drying was 125 占 퐉. The applied liquid composition was dried by heating at 130 캜 for 10 minutes and then cured by heating at 185 캜 for 30 minutes. After peeling the mold releasing PET film, the cured product was punched to a width of 10 mm and a length of 100 mm to obtain a test piece. This test piece was subjected to a tensile test in which the tensile strength was elongated in the longitudinal direction at a tensile speed of 50 mm / min using an EZ tester (Autograph EZ-S, Shimadzu Seisakusho Co., Ltd.) to obtain a stress-displacement curve. The maximum value of the slope of the tangent line of the stress-displacement curve at the start of the operation after the start of the stress load was obtained, and the initial tensile elastic modulus was obtained from the value according to the following formula.

Initial tensile modulus (Pa) = maximum value of tangent slope of stress-displacement curve (N / m) x [displacement (m) / cross-

Example 1

A copper foil of a laminate of a polyimide base material (thickness 25 占 퐉) / copper foil (thickness 18 占 퐉) (Etspanex, trade name, manufactured by Shin-Etsu Tiga Kakuga) was processed by photolithography, Pattern. The liquid composition of Production Example 1 was printed on the surface opposite to the wiring terminal of the polyimide substrate using a metal mask. The printed liquid composition was dried by heating at 130 DEG C for 10 minutes and then cured by heating at 185 DEG C for 60 minutes to form a resin layer having a length of 30 mm and a thickness of 75 mu m from the end of the polyimide base material, A test piece (width 10 mm, length 100 mm) of a connector having a ground layer was obtained. The end of the resin layer having the substantially rectangular main surface had a surface forming a convex curved surface curved toward the polyimide substrate from the opposed surface opposed to the polyimide substrate.

Examples 2 to 12

A connector having a resin layer was obtained in the same manner as in Example 1 except that the thickness of the polyimide base material or the thickness of the resin layer was changed as shown in Tables 3 and 4, A test piece was produced. In both test pieces, the end portion of the resin layer had a surface forming a convex curved surface curved toward the polyimide substrate from the opposed surface opposed to the polyimide substrate.

Comparative Example 1

A wiring terminal pattern was formed on a polyimide substrate (thickness: 50 mu m) in the same manner as in Example. On the surface opposite to the wiring terminals of the polyimide base material, a polyimide film (a film of 75 mu m in thickness, 75 mu m in thickness) was formed through a 30 mu m-thick adhesive film (Hybond 10-850, trade name, manufactured by Hitachi, Manufactured by Takayama Kogyo Co., Ltd.), and cut into a rectangular shape having a width of 10 mm and a length of 100 mm to obtain a comparative connector test piece. The end portion of the polyimide film adhered to the polyimide substrate had a facing surface opposed to the polyimide substrate and a side surface along the repair line of the polyimide substrate.

(evaluation)

(Bending)

A load of 490 mN (50 gf) was applied from the end portion by pushing the end portion of the test piece having a width of 10 mm with a balance. A "when the load was not applied," A "when the test piece was not bent, and" C "when the test piece was bent or the resin layer was broken.

(Resistance to reflow)

A conveyor type reflow test of a heating profile in which a test piece of a connector was sandwiched between two pieces of wire netting and the temperature of the substrate surface temperature was maintained at 260 占 폚 for 10 seconds while moving at a speed of 1.2 m / , And the test piece was treated three times. After the treatment, the appearance was visually observed to confirm the swelling and peeling between the polyimide base / resin layers. A " when expansion and peeling did not occur, and " C " when expansion and / or peeling occurred.

(Durability test of connector)

8 is a schematic explanatory view showing a durability test method of a connector. Finished mirror-finished aluminum plates 31 and 31 having a thickness of 1 mm fixed to each of the spindle 21 and the anvil 22, which are measurement portions of the digital micrometer 20 (manufactured by Mitsutoyo MDC-25SB) 32) was used as a jig for evaluation of durability. The gap between the two opposing aluminum plates 31 and 32 was set by the digital micrometer 20 to be equal to the thickness of the test piece, or to -15 占 퐉 or +15 占 퐉. After inserting the test piece 10 in a gap of about 10 mm in the direction A parallel to the aluminum plate, the drawing operation was repeated 30 times at maximum. The abnormality of the test piece 10 was visually observed to record the number of times until an abnormality such as peeling, cracking, bending or the like occurred.

(Adhesiveness between the polyimide substrate and the resin layer)

The liquid composition was applied to a polyimide film (Epilex 50S, product of Ube Gosan Co., Ltd.) so that the thickness after drying was 125 占 퐉, using a bar coater. The applied liquid composition was dried by heating at 130 占 폚 for 10 minutes and then cured by heating at 185 占 폚 for 30 minutes to obtain a sample for evaluation of adhesion. In the resin layer of the sample, marks of 10 checkerboards were inserted in a width of 2 mm by a cutter knife and 10 in a width of 2 mm so as to cross at right angles. Cellotape (registered trademark) was attached thereon, and then it was peeled off to confirm whether or not the resin layer was peeled off. &Quot; A " when peeling did not occur, and " C " when peeling occurred.

(result)

The evaluation results are shown in Tables 3 and 4. In the examples, all of the polyimide substrate and the resin layer were satisfactory, and resistance to reflow was not a problem. Regarding the bending property of the connector, in all the examples, the test piece was not bent with respect to a load of 490 mN (50 gf).

With respect to the durability test of the connector, in the examples, the test piece can be smoothly pulled out, and even when pulling out 30 times, no occurrence of abnormality was observed. In the case of the comparative example, when the gap of the test piece was equal to (173 占 퐉) or -15 占 퐉 (158 占 퐉) due to a strong pulling-out resistance of the test piece,

9 is a photomicrograph of a section of the connector manufactured in Example 1. Fig. It was confirmed by microscopic observation that the end of the resin layer 3 had a surface forming a convex curved surface curved toward the polyimide substrate 2 from the opposed surface opposed to the polyimide substrate. 10 is a scanning micrograph (10,000 times) of the resin layer of the connector produced in Example 1. Fig. It has been confirmed that spherical silica particles are contained in the resin layer.

1 ... wiring terminal 2 ... flexible substrate
3 ... resin layer 3a ... end of the resin layer 3
4 ... metal mask 4a ... opening
5 ... liquid composition 6 ... facing face
7 ... surface 10 forming a convex surface ... connector
20 ... Digital micrometer 21 ... Spindle
22 ... anvil 31, 32 ... aluminum plate
40 ... flexible substrate 41 ... cover film
42 ... non-wiring metal layer 51 ... circuit
52 ... Flexible substrate for circuit 100 ... Flexible wiring board

Claims (9)

An insertion-side connector inserted into a mating connector and used for connecting wiring,
A flexible substrate (flexible substrate)
A wiring terminal disposed on one side of the flexible substrate,
And a resin layer including a resin, the resin layer being disposed on an end portion of the flexible substrate on the side opposite to the wiring terminal of the flexible substrate and having a facing surface facing the flexible substrate,
And the front end of the connector of the resin layer has a surface forming a convex curved surface that curves from the opposed surface toward the flexible substrate. The method according to claim 1,
Wherein the resin layer further comprises an inorganic filler. The method of claim 2,
Wherein the inorganic filler is silica particles. The method according to claim 2 or 3,
Wherein the content of the inorganic filler in the resin layer is 30 to 70% by volume with respect to the volume of the resin layer. 5. The method according to any one of claims 1 to 4,
Wherein the flexible substrate is a polyester substrate or a polyimide substrate. 6. The method according to any one of claims 1 to 5,
Wherein the thickness of the flexible substrate is 75 mu m or less. 7. The method according to any one of claims 1 to 6,
Wherein the resin layer has an initial tensile modulus at 25 占 폚 of 0.3 to 3.0 mm. The method according to any one of claims 1 to 7,
Wherein a thickness of the resin layer is 50 to 500 mu m. A connector comprising: the connector according to any one of claims 1 to 8;
A circuit flexible substrate,
A circuit provided on the flexible substrate for the circuit and connected to the wiring terminal of the connector,
Wherein the flexible substrate of the connector and the flexible substrate for circuit are the same substrate or the flexible substrate of the connector is connected to the flexible substrate for the circuit.

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