KR20180104484A - Transparent cover-lay film having low elestic modulus and flexible printed circuit board including the same - Google Patents

Abstract

The present invention relates to a transparent cover-lay film having low elasticity and to a manufacturing method thereof, wherein an adhesive having low elasticity properties is included in the transparent cover-lay film, so that flexibility is ensured because the modulus of elasticity is lower than the modulus of elasticity of conventional cover-lay films and a colorless transparent cover-lay film and a flexible printed circuit board (FPCB) using the same can be provided.

Description

[0001] The present invention relates to a low-elastic transparent coverlay film and a flexible cover-lay film (FPCB)

 The present invention relates to a coverlay film having low elasticity and transparency and an FPCB having the same. More particularly, the present invention relates to a coverlay film which has flexibility lower than that of a conventional coverlay film, .

2. Description of the Related Art In recent years, there has been an increasing need for printed circuit boards (PCBs) that are easy to be embedded even in a narrower space due to integration, miniaturization, thinning, high density and high bending of electronic products. Accordingly, a Flexible Printed Circuit Board (FPCB) capable of miniaturization and high density and having repeated flexing has been developed. Such a flexible printed circuit board is being used more rapidly due to the technological development of smart phones, portable mobile electronic devices (smart watches, smart glasses, etc.), and the demand thereof is increasing.

Generally, in order to manufacture a flexible printed circuit board, a flexible film is formed on a flexible copper clad laminate in which a copper foil layer is formed on both sides or an end face of an insulating base film such as polyimide having high heat resistance and high flexibility, a dry film is laminated on the surface of the substrate and then a circuit pattern is formed by exposure, development and etching in sequence, and then a coverlay film is bonded to the outside of the circuit pattern and hot- A circuit board is manufactured.

The flexible copper-clad laminate is composed of a three-layer type composed of three layers of a copper foil, a polyimide base film and an epoxy thermosetting adhesive layer, a two-layer type having a polyimide-based adhesive which is homogeneous with the polyimide base film, There is also a two-layer type that does not have an adhesive layer. In addition, the coverlay is laminated for the purpose of protecting the copper wiring of the copper-clad laminate, and is generally composed of a polyimide base film and an epoxy thermosetting adhesive layer. At this time, in order to exhibit a stable performance, an adhesive composition mainly composed of an epoxy resin having good heat resistance and chemical resistance has been widely used as an adhesive for use in an electronic material such as a semiconductor sealing material or an epoxy-based FPCB.

Korean Patent Application No. 2014-0084415 of the prior art discloses a non-halogen fast curing adhesive composition and a coverlay film using the same, and Korean Patent Application No. 2012-0117438 discloses a method of producing a flexible printed circuit board .

However, since the coverlay film including such an adhesive composition is not ensured in flexibility due to excessive rigidity, the FPCB including the coverlay is manufactured, and the fairness and reliability of parts mounting on a wearable device, I had a problem.

In addition, the polyimide layer and the adhesive layer constituting the conventional coverlay film are opaque yellow. Recently, display-equipped products and / or electronic parts have been increasingly required to have transparency for internal parts together with flexible and aesthetic reasons, It is expected that devices will create high value-added markets in various fields such as home, industrial, and education. FPCB should also be developed as a transparent base for marketable transparent displays. Especially, Resistor wiring is required. However, even in a technology-leading country, transparent FPCB is being developed, but the formation of low resistance transparent wiring using Cu has not yet been attempted.

Transparent FPCB is essential for high transparency, but it requires high-temperature solder reflow process when it is connected with various devices. Therefore, it is necessary to secure high heat resistance of transparent material, and it is necessary to manufacture technology compatible with PCB process and roll- ) Mass production is absolutely necessary to reduce the price of transparent FPCB.

In order to manufacture such a transparent FPCB, a fine circuit forming technique or the like is applied. Therefore, there is a growing need to develop a colorless transparent cover film material while satisfying rigidity and flexibility at the same time.

Korean Patent Publication No. 10-2014-0084415 (published July 2014.07)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a coverlay film which has flexibility lower than that of a conventional coverlay film and satisfies transparency while ensuring flexibility.

In order to solve the above-described problems, the low-elasticity transparent coverlay film of the present invention comprises a transparent substrate layer and a transparent adhesive layer on one side of the transparent substrate layer.

According to a preferred embodiment of the present invention, the thickness of the transparent base layer and the thickness of the transparent adhesive layer of the low elastic clear coverlay film of the present invention may be 5 to 25 μm and 5 to 40 μm, respectively.

According to a preferred embodiment of the present invention, the low elastic clear coverlay film of the present invention may have a metal foil layer, a first adhesive layer, a transparent substrate layer, and a second adhesive layer sequentially laminated.

According to a preferred embodiment of the present invention, the first adhesive layer may be a transparent adhesive layer or an opaque adhesive layer, and the second adhesive layer may be a transparent adhesive layer.

According to a preferred embodiment of the present invention, the low elastic clear coverlay film of the present invention has an average thickness P ₁ of the first adhesive layer, an average thickness P ₂ of the transparent base layer, and the average thickness (P ₃₎ is to satisfy the equation (1), the second adhesive layer may have a modulus of elasticity, preferably a modulus of elasticity of 0.5 ~ 0.1 ~ 1.5Gpa of 2.0Gpa during curing.

[Equation 1]

0.1? (P ₁ + P ₂ ) / P ₃ ? 9.0

In the above equation (1), P ₃ is a rational number satisfying 5 μm ≦ P ₃ ≦ 40 μm.

According to a preferred embodiment of the present invention, the first adhesive layer of the low elastic clear coverlay film of the present invention is in a cured state, and the second adhesive layer may be semi-cured.

According to a preferred embodiment of the present invention, the transparent substrate layer may include at least one selected from transparent polyimide (PI) resin, transparent polyethylene terephthalate (PET) resin and transparent polyethylene naphthalate (PEN) resin .

According to a preferred embodiment of the present invention, the transparent PI resin is a dianhydride including at least one selected from the group consisting of dianhydrides represented by the following formula (1); And diamines represented by the following formula (2): ## STR2 ## wherein R 1 is a hydrogen atom or a methyl group;

[Chemical Formula 1]

,

,

,

,

,

,

,

,

또는

이며,In the formula 1, wherein R ₁ is

,

,

,

,

,

,

,

,

or

Lt;

(2)

H ₂ NR ₂ -NH ₂

,

,

,

,

,

,

,

또는

이다.In formula (2), R ₂ is

,

,

,

,

,

,

,

or

to be.

According to a preferred embodiment of the present invention, the transparent adhesive layer, the transparent first adhesive layer, and / or the second adhesive layer are formed of a transparent material including an epoxy thermosetting resin, an acrylic binder resin, a curing agent, a catalyst, a filler and a silane coupling agent Adhesives.

According to a preferred embodiment of the present invention, the epoxy thermosetting resin may include a cycloaliphatic epoxy resin, and the cycloaliphatic epoxy resin may include bisphenol-A type epoxy, bisphenol F Bisphenol-F type epoxy, bisphenol-S type epoxy, bisphenol-AD type epoxy, phenol novolac epoxy, cresol novolac epoxy, Novolac Epoxy, bisphenol-A Novolac type epoxy, dicycolpentadiene type epoxy and multi-functional novolac type epoxy. . ≪ / RTI >

According to a preferred embodiment of the present invention, the acrylic binder resin may include a cyanoacrylate binder resin represented by the following formula (3).

(3)

In Formula (3), R ₁ is an alkyl group, an alkoxyalkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, an allyl group or a haloalkyl group of C ₁ to C 15.

According to a preferred embodiment of the present invention, the curing agent may include at least one selected from a phenol-based curing agent, an acid anhydride-based curing agent, an amine-based curing agent and an imidazole-based curing agent.

According to a preferred embodiment of the present invention, the filler is an inorganic filler comprising at least one selected from aluminum oxide, magnesium hydroxide and calcium carbonate; And phosphine type fillers; And the like.

According to a preferred embodiment of the present invention, the catalyst may be an imidazole compound such as a 2-alkyl-4-methylimidazole compound, a 2-alkyl-4-ethylimidazole compound or a 2-phenylimidazole compound; Metal boron fluoride compounds consisting of tin boron fluoride and zinc boron fluoride; And metal octoate compounds consisting of boron trifluoride, tin octoate and zinc octoate; And the like.

According to a preferred embodiment of the present invention, the silane coupling agent is selected from the group consisting of an epoxy group-containing silane coupling agent, an amino group-containing silane coupling agent, a vinyl tri (C1 to C3 alkoxy) silane-containing silane coupling agent, 3-methacryloxypropylmethyldimet Containing silane coupling agent and 3-methacryloxypropyltrimethoxysilane-containing silane coupling agent.

According to a preferred embodiment of the present invention, the transparent adhesive layer has a light transparency of at least 91%, preferably at least 93%, at a wavelength of 500 nm, a glass transition temperature (Tg) 200 < 0 > C.

According to a preferred embodiment of the present invention, the transparent adhesive layer may have an adhesive strength of 0.6 kg / cm ² or more, preferably 0.7 kg / cm ^{2 or} more.

According to a preferred embodiment of the present invention, the thickness (P ₁ ) of the first adhesive layer is 5 탆 to 20 탆, the thickness (P ₂ ) of the transparent base layer is 5 탆 to 20 탆, And the thickness (P ₃ ) of the second adhesive layer may be 5 탆 to 40 탆.

According to another preferred embodiment of the present invention, the first adhesive layer of the low elastic clear coverlay film of the present invention may comprise thermoplastic polyimide (TPI) resin, and the thickness of the first adhesive layer (P ₁ ) may be 1 탆 to 10 탆, the thickness (P ₂ ) of the transparent base layer may be 5 탆 to 25 탆, and the thickness (P ₃ ) of the second adhesive layer may be 5 탆 to 40 탆.

According to another preferred embodiment of the present invention, the metal foil layer of the low elasticity coverlay film of the present invention includes a copper foil or an aluminum foil, and the thickness of the metal foil layer may be 2 to 40 mu m.

According to a preferred embodiment of the present invention, the low elastic clear coverlay film of the present invention further comprises a protective substrate layer on one side of the second adhesive layer, and the thickness of the protective substrate layer may be 6 to 200 탆.

According to a preferred embodiment of the present invention, the protective substrate layer of the low elastic clear coverlay film of the present invention may include at least one of a paper film and a plastic resin film.

(1) forming a transparent base film; And (2) coating a transparent adhesive on one surface of the transparent base film. The present invention also provides a method for producing a low elastic clear coverlay film.

(1) forming a transparent base film; (2) sequentially laminating a first adhesive layer and a metal foil layer on one side of the transparent substrate film; And (3) laminating a second adhesive layer on the other surface of the transparent base film, thereby providing a method of producing a low elastic clear coverlay film.

According to a preferred embodiment of the present invention, the average thickness of the first adhesive layer (P _1), the average thickness of the transparent substrate layer (P ₂₎ and the second average thickness of the adhesive layer (P ₃₎ has the formula (1) And the second adhesive layer may have an elastic modulus of 0.1 to 2.0Gpa, preferably 0.5 to 1.5Gpa when cured.

According to a preferred embodiment of the present invention, the transparent substrate film is formed of at least one resin selected from transparent polyimide (PI) resin, transparent polyethylene terephthalate (PET) resin and transparent polyethylene naphthalate (PEN) resin .

According to a preferred embodiment of the present invention, the first adhesive layer may be formed of an opaque adhesive or a transparent adhesive, and the second adhesive layer may be formed of a transparent adhesive.

According to a preferred embodiment of the present invention, the transparent adhesive may include an acrylic adhesive.

According to a preferred embodiment of the present invention, the transparent first adhesive layer and / or the second adhesive layer of the low elastic clear coverlay film producing method of the present invention is formed of a transparent adhesive containing an acrylic adhesive, The average thickness (P ₁ ) of the adhesive layer is 5 탆 to 20 탆, the average thickness (P ₂ ) of the transparent base layer is 5 탆 to 25 탆, the average thickness (P ₃ ) of the second adhesive layer is 5 탆 to 40 탆 Lt; / RTI >

According to a preferred embodiment of the present invention, the first adhesive layer of the low elastic clear coverlay film of the present invention comprises a thermoplastic polyimide (TPI) resin, wherein the average The thickness (P ₁ ) may be 1 탆 to 20 탆, the average thickness (P ₂ ) of the transparent base layer may be 5 탆 to 25 탆, and the average thickness (P ₃ ) of the second adhesive layer may be 5 탆 to 40 탆.

Further, in order to solve the above-mentioned problems, the present invention provides a low-elasticity FPCB comprising the above-mentioned transparent coverlay film.

According to another preferred embodiment of the present invention, the low elastic FPCB of the present invention can be used in at least one of a cellular phone, a camera, a notebook, and a wearable device.

INDUSTRIAL APPLICABILITY The low-elasticity transparent coverlay film of the present invention and the method for producing the same are excellent in flexibility because they have adhesiveness with a low elasticity property and are lower in elasticity than conventional coverlay films, and they can satisfy rigidity, A cover type film of a transparent type can be provided.

1 and 2 are sectional views of a coverlay film according to a preferred embodiment of the present invention.

As used herein, the term " transparent " means colorless transparent.

Hereinafter, the present invention will be described in more detail.

The low elastic clear coverlay film of the present invention comprises a transparent substrate layer 30 and a transparent adhesive layer 40 on one side of the transparent substrate layer as shown in Fig. 1, which comprises (1) forming a transparent substrate film ; And (2) coating a transparent adhesive on one surface of the transparent base film.

The transparent base layer is formed by filming a resin containing at least one selected from transparent polyimide (PI) resin, transparent polyethylene terephthalate (PET) resin and transparent polyethylene naphthalate (PEN) resin, And may be formed by forming a resin including a polyimide (PI) resin into a film.

Wherein the transparent PI resin is a dianhydride containing at least one selected from the group consisting of dianhydrides represented by the following formula (1); And a diamine represented by the following formula (2): ## STR2 ## wherein R is a hydrogen atom or a methyl group;

[Chemical Formula 1]

,

,

,

,

,

,

,

,

또는

이며, 바람직하게는

,

,

,

또는

이다.In the formula 1, wherein R ₁ is

,

,

,

,

,

,

,

,

or

, And preferably

,

,

,

or

to be.

(2)

H ₂ NR ₂ -NH ₂

,

,

,

,

,

,

,

또는

이며, 바람직하게는

,

,

,

또는

이다.In formula (2), R ₂ is

,

,

,

,

,

,

,

or

, And preferably

,

,

,

or

to be.

The thickness of the transparent base layer may be 5 占 퐉 to 25 占 퐉, and the thickness of the transparent adhesive layer may be 5 占 퐉 to 40 占 퐉.

Further, the low elastic clear coverlay film of the present invention comprises the steps of: (1) forming a transparent base film; (2) sequentially laminating a first adhesive layer and a metal foil layer on one side of the transparent substrate film; And (3) a step of laminating a second adhesive layer on the other surface of the transparent base film. As a result, the metal foil layer 10, the first adhesive layer 20, the transparent base layer 30, And the second adhesive layer 40 are laminated in this order. Here, the transparent base layer is the same as the transparent base layer described above.

In the step (2), the first adhesive layer is coated on one side of the transparent substrate layer, and then the first adhesive layer is dried by heat treatment at 30 to 190 ° C for 1 to 10 minutes. Specifically, a composition of the first adhesive layer is uniformly coated on one surface of the transparent substrate layer using a reverse roll coater, a die coater, a comma coater, Preferably at 50 to 170 ° C for 2 to 4 minutes, through an in-line drying oven to dry the first adhesive layer laminated on one surface of the transparent substrate layer.

Next, a metal foil layer is laminated on the surface of the first adhesive layer through a heating roller at 30 to 100 DEG C by applying a spinning of 1 to 10 kg / cm. Specifically, the metal foil layer is preferably laminated to the dried surface of the first adhesive layer on the transparent base layer via a heating roller at a linear pressure of preferably 4 to 7 kg / cm, preferably at 50 to 70 ° C.

Finally, the first adhesive layer is cured by heat treatment at 20 to 190 DEG C for 100 to 400 minutes. Specifically, in order to more effectively cure the first adhesive layer, the sections are divided in the range of 40 to 180 DEG C and cured under elevated temperature conditions. Preferably 150 to 170 DEG C for 60 to 180 minutes.

Next, in the step (3), the second adhesive layer is coated on one surface of the protective substrate layer, and then the second adhesive layer is dried by heat treatment at 30 to 190 ° C for 1 to 10 minutes. Specifically, a composition of the second adhesive layer is uniformly applied to one side of the protective substrate layer using a reverse roll coater, a die coater and a comma coater on one side of the protective substrate layer, And then heat-treated at 30 to 190 ° C, preferably 50 to 170 ° C, for 2 to 4 minutes through an in-line drying oven to laminate and dry the second adhesive layer. Thereafter, a second adhesive layer is laminated on the other surface of the transparent base layer, and a linear pressure of 5 to 7 kg / cm is applied, and the second adhesive layer can be bonded to the other surface of the transparent base layer through a heating roller at 50 to 80 ° C. Finally, the second adhesive layer is semi-cured by heat treatment at 40 to 80 ° C for 6 to 100 hours. Specifically, for further effective semi-curing of the second adhesive layer, additional heat treatment may be performed at 40 to 80 ° C, preferably 50 to 70 ° C for 12 to 72 hours.

In addition, in the step (3), the second adhesive layer is coated on the other surface of the transparent substrate layer, and then the second adhesive layer is dried by heat treatment at 30 to 190 ° C for 1 to 10 minutes. Specifically, a composition of the second adhesive layer is uniformly applied to the other surface of the transparent substrate layer using a reverse roll coater, a die coater, and a comma coater on the other surface of the transparent substrate layer, And then heat-treated at 30 to 190 ° C, preferably 50 to 170 ° C, for 2 to 4 minutes through an in-line drying oven to laminate and dry the second adhesive layer. At this time, the protective substrate layer may be bonded to the surface of the dried second adhesive layer on the other side of the transparent substrate layer through a heating roller at 50 to 80 ° C under a linear pressure of 5 to 7 kg / cm.

Finally, the second adhesive layer is semi-cured by heat treatment at 40 to 80 ° C for 6 to 100 hours. Specifically, for further effective semi-curing of the second adhesive layer, additional heat treatment may be performed at 40 to 80 ° C, preferably 50 to 70 ° C for 12 to 72 hours.

So according to the manufacture, that the elastic transparent cover lay film having a 5-layer structure, an average thickness of the first adhesive layer (P _1), the average thickness of the transparent substrate layer (P ₂₎ and the average thickness of the second adhesive layer (P ₃ ) satisfies the following formula (1), and the second adhesive layer may have a modulus of elasticity of 0.1 to 2.0Gpa, preferably 0.5 to 1.5Gpa when cured, The elasticity is lower than that, so that not only the flexibility can be ensured, but also the stiffness can be satisfied.

[Equation 1]

0.1? (P ₁ + P ₂ ) / P ₃ ? 9.0

In the above equation (1), P ₃ is a rational number satisfying 5 μm ≦ P ₃ ≦ 40 μm.

If the coverlay film 200 of the present invention is out of the range of Equation (1), the rigidity and flexibility required by the coverlay film 200 of the present invention can not be satisfied. In other words, if P ₁ + P ₂ / P ₃ in the above formula (1) is less than 0.1, the problem of stiffness and handling will arise, and if the coverage film 200 of the present invention satisfies P ₁ + P ₂ / If P ₃ exceeds 9.0, there is a problem of ductility.

Further, if the second adhesive layer 40 deviates from the elastic modulus of 0.1 to 2.0 Gpa during curing, the rigidity and flexibility required by the coverlay film 200 of the present invention can not be satisfied. In other words, when the modulus of elasticity is less than 0.1 GPa, the rigidity of the coverlay film is low, so that it is easily broken by external impact. When the modulus of elasticity exceeds 2.0 GPa, the rigidity of the coverlay film is excellent, May occur. Accordingly, the coverlay film 200 of the present invention not only meets the above-mentioned formula (1), but also satisfies the above-mentioned formula (1), and the second adhesive layer 40 satisfies the elasticity of 0.1 to 2.0Gpa You can be satisfied.

2, the cover layer film 200 of the present invention is formed by laminating the metal foil layer 10, the first adhesive layer 20, the transparent base layer 30 and the second adhesive layer 40 in sequence.

The metal foil layer 10 is a metal having conductivity and ductility and is laminated on one side of the first adhesive layer 20 and may be provided with a circuit pattern. And may be formed by patterning in a desired shape. The metal foil layer 10 may include at least one of a thin copper foil, an aluminum foil, a tungsten foil foil and an iron foil foil and preferably has excellent flexibility and high electrical conductivity Or an aluminum foil having an aluminum foil.

If the thickness of the metal foil layer 10 is less than 2 탆, the productivity of the FPCB of the present invention may deteriorate. In this case, the thickness of the metal foil layer 10 may be in the range of 2 탆 to 70 탆, preferably 12 탆 to 40 탆, If it exceeds 40 탆, it may be difficult to impart ductility to the coverlay film 200 to be manufactured.

The first adhesive layer 20 is formed between the metal foil layer 10 and the transparent substrate layer 30 in a cured state and serves to adhere the metal foil layer 10 and the transparent substrate layer 30, It can be formed of an adhesive.

The first adhesive layer 20 may comprise a thermosetting epoxy adhesive.

The thermosetting epoxy adhesive may contain 1) a butadiene-acrylonitrile copolymer represented by the following formula (4) containing a carboxyl polyamide aminocarbonyl group (A) and a polysiloxane aminocarbonyl group (B) and 2) an epoxy resin.

[Chemical Formula 4]

Wherein m is from 3 to 200 and n is from 0.2 to 100 with respect to k = 1, and the molar ratio of k to m is from 1 to 100, R ₁ and R ₂ are C ₁ to C ₂₀ alkyl groups, R ₃ is a C ₁ to C ₂₀ alkyl group, and O, P and Q are integers of 1 to 20.

The weight average molecular weight of the butadiene-acrylonitrile copolymer is 10,000 to 200,000, and the content of the acrylonitrile unit in the butadiene-acrylonitrile copolymer may be 2 to 40% by weight.

The thermosetting epoxy adhesive may contain 10 to 900 parts by weight, preferably 50 to 700 parts by weight, of the epoxy resin with respect to 100 parts by weight of the butadiene-acrylonitrile copolymer.

The epoxy resin may be a bisphenol-A type epoxy, an O-cresol novolac type epoxy, a phenol novolak type epoxy, a low-chlorine type epoxy, , A dicycolpentadiene type epoxy and a multi-functional novolac type epoxy, and the epoxy resin may contain at least one compound selected from bromine-substituted compounds And may further include one or more species

The thermosetting epoxy adhesive may further contain at least one epoxy curing agent selected from the group consisting of an aliphatic amine compound, an aromatic amine compound, an acid anhydride compound, dicyandiamide, and boron trifluoride, based on 100 parts by weight of the butadiene-acrylonitrile copolymer And may further contain 5 to 25 parts by weight.

The thermosetting epoxy adhesive is prepared by mixing 100 parts by weight of a butadiene-acrylonitrile copolymer with 2-alkyl-4-methylimidazole compound, 2-alkyl-4-ethylimidazole compound, , Metal boron fluoride compounds composed of boron tin fluoride and zinc boron fluoride; And a metal octoate compound composed of tin octoate and zinc octoate; and 0.1 to 2.0 parts by weight of at least one promoter selected from the group consisting of tin octoate and zinc octoate.

Wherein the thermosetting epoxy adhesive comprises 25 to 200 parts by weight of an inorganic filler selected from the group consisting of aluminum hydroxide, magnesium hydroxide, aluminum oxide, zinc oxide, and magnesium oxide and having a particle size of 5 mu m or less based on 100 parts by weight of the butadiene- acrylonitrile copolymer. By weight.

When the first adhesive layer 20 includes the above-described thermosetting epoxy adhesive, the thickness of the first adhesive layer 20 is not particularly limited. However, considering the thickness of the metal foil layer and the ductility of the FPCB to be produced, To 20 mu m, preferably from 5 mu m to 10 mu m. If the thickness of the first adhesive layer 20 is less than 5 mu m, there may arise a problem that the metal foil layer is separated at the interface of the first adhesive layer 20 during the FPCB manufacturing process or the use of the FPCB manufactured due to the lowering of the adhesive force. If it is more than 탆, a problem of ductility deterioration may occur.

Further, the first adhesive layer 20 may include a thermoplastic polyimide (TPI) resin. The thermoplastic polyimide resin can be produced by using polyamic acid as a precursor. However, the polyamic acid which is a precursor of the thermoplastic polyimide resin is not particularly limited, and all polyamic acids can be used.

The thermoplastic polyimide resin may include one or more of thermoplastic polyamide imide, thermoplastic polyether imide, and polyester imide, but is not limited thereto. Can include known materials without limitation. The thermoplastic polyimide resin may include inert inorganic particles. The inert inorganic particles may be added to improve the slip property of the first adhesive layer 20 including the thermoplastic polyimide resin.

At this time, it is preferable that the inert inorganic particles are dispersed in 0.01 to 10 parts by weight with respect to 100 parts by weight of the thermoplastic polyimide resin. At this time, when the content of the inert inorganic particles is less than 0.01 part by weight, the effect of the addition may be insufficient. On the other hand, when the content of the inert inorganic particles exceeds 10 parts by weight, the flexibility of the first adhesive layer 20 including the thermoplastic polyimide resin may be reduced.

The average particle diameter of the inert inorganic particles may be in the range of 50 to 1,000 nm, preferably 100 to 500 nm. When the average particle diameter of the inert inorganic particles is less than 50 nm, the modification effect such as slip property due to the improvement of the center line average roughness Ra of the first adhesive layer 20 including the thermoplastic polyimide resin may not be sufficient. On the other hand, when the average particle size of the inert inorganic particles exceeds 1000 nm, an excessive roughness is formed in the first adhesive layer 20 including the thermoplastic polyimide resin, thereby causing problems such as sticking with the metal foil layer 10 Can cause.

Silica (SiO ₂ ) can be used as the inert inorganic particles. The shape of the silica is not particularly limited, but silica such as a spherical shape, a needle shape, a cubic shape, and a scaly shape can be used. However, it is preferable to use spherical silica in consideration of the surface property of the first adhesive layer 20 including the thermoplastic polyimide resin.

When the first adhesive layer 20 includes a thermoplastic polyimide resin (TPI), the thickness P ₁ of the first adhesive layer 20 is not particularly limited, but the thickness of the metal foil layer and the thickness Considering the ductility of the FPCB, etc., it may be 1 占 퐉 to 10 占 퐉, preferably 1 占 퐉 to 5 占 퐉. If the thickness of the first adhesive layer 20 is less than 1 mu m, there may arise a problem that the metal foil layer is separated at the interface of the first adhesive layer 20 during the FPCB manufacturing process or the use of the manufactured FPCB due to the lowering of the adhesive strength. If it is more than 탆, a problem of ductility deterioration may occur.

The transparent substrate layer 30 is formed between the first adhesive layer 20 and the second adhesive layer 40 and is formed of a transparent polyimide (PI) resin, a transparent polyethylene terephthalate (PET) resin and a transparent polyethylene naphthalate (PEN) resin, preferably a resin containing a transparent polyimide (PI) resin, into a film. As described above, the transparent polyimide resin may include dianhydride including at least one selected from the group consisting of the dianhydrides represented by Formula 1; And a diamine represented by the following formula (2): ## STR2 ## wherein R is a hydrogen atom or a methyl group;

The thickness of the transparent base layer 30 is not particularly limited, but may be 5 탆 to 25 탆, preferably 5 탆 to 15 탆, in consideration of the thickness of the coverlay film 200 to be manufactured. If the thickness of the transparent substrate layer 30 is less than 5 mu m, the workability of the flexible circuit board may be lowered. If the thickness of the transparent substrate layer 30 is more than 25 mu m, the ductility may be deteriorated.

The transparent adhesive layer 40 shown in Fig. 1 and / or the second adhesive layer 40 shown in Fig. 2 are laminated on one side of the transparent substrate layer 30 in a semi-cured state.

When the transparent adhesive layer 40 and / or the second adhesive layer 40 and / or the first adhesive layer 20 shown in FIG. 2 are transparent adhesive layers, each of the adhesive layers may be an epoxy thermosetting resin, A transparent adhesive including a resin, a curing agent, a catalyst, a filler, and a silane coupling agent.

The epoxy-based thermosetting resin is converted into a strong molecular bonding structure having a net structure as the chemical bonding reaction between the epoxy resin components proceeds after curing, thereby improving the heat resistance and moisture resistance of the final bonded body, It plays a role. The epoxy-based thermosetting resin may include a cycloaliphatic epoxy resin. Examples of the cycloaliphatic epoxy resin include bisphenol-A type epoxy, bisphenol-F type epoxy, Bisphenol-S type epoxy, bisphenol-AD type epoxy, phenol novolac epoxy, cresol novolac epoxy, bisphenol-A novolak type epoxy resin, Low-chlorine type epoxy, rubber-modified epoxy, fatty-modified epoxy, urethane-modified epoxy, epoxy-modified epoxy, A silane-modified epoxy, a dicycolpentadiene type epoxy and a multi-functional novolac type epoxy, wherein the silane- Preferred are bisphenol-A type epoxy, bisphenol-A novolac type epoxy, O-cresol novolac type epoxy, dicyclopentadiene, A dicycolpentadiene type epoxy and a multi-functional novolac type epoxy.

In the acrylic binder resin, the acrylic binder resin may include a cyanoacrylate binder resin represented by the following formula (3).

(3)

In Formula (3), R ₁ is an alkyl group, an alkoxyalkyl group, a cycloalkyl group, an alkenyl group, an aralkyl group, an aryl group, an allyl group or a haloalkyl group of C ₁ to C 15.

The acrylic binder resin may be used in an amount of 30 to 80 parts by weight, preferably 30 to 60 parts by weight, based on 100 parts by weight of the epoxy thermosetting resin. When the amount of the acrylic binder resin used is less than 30 parts by weight, There may be a problem that it is not ensured, and if it exceeds 80 parts by weight, there may be a problem that the curing of the adhesive proceeds too quickly.

The filler serves to reduce the cost and the elastic modulus of the transparent adhesive layer 40 and / or the second adhesive layer 40, and the filler is an inorganic filler such as aluminum hydroxide, magnesium hydroxide, calcium carbonate An inorganic filler, and a phosphine type filler, and may preferably include an aluminum hydroxide type filler or a phosphorous type filler. The filler may be used in an amount of 20 to 100 parts by weight, preferably 30 to 80 parts by weight, based on 100 parts by weight of the epoxy thermosetting resin. If the amount of the filler used is less than 20 parts by weight, If it exceeds 100 parts by weight, there may be a problem of deterioration of adhesion.

The hardener serves to improve the heat resistance of the transparent adhesive layer 40 and / or the second adhesive layer 40 (including the case where the first adhesive layer is a transparent adhesive layer), and the hardener is an amine type hardener a hardener, a phenol type hardener, an acid anhydride type hardener, an imidazole compound, a polyamine compound, a hydrazine compound, a dicyandiamide compound ), And may preferably include at least one of an amine type hardener, a phenol type hardener, and an acid anhydride type hardener. The curing agent may be used in an amount of 10 to 100 parts by weight, preferably 15 to 50 parts by weight, based on 100 parts by weight of the epoxy thermosetting resin. If the amount of the curing agent is less than 10 parts by weight, If it exceeds the weight part, there may be a problem of deterioration of the adhesive strength.

In addition, the catalyst serves to promote curing of the transparent adhesive layer 40 and / or the second adhesive layer 40 (including the case where the first adhesive layer is a transparent adhesive layer) Heat resistance and the like can be improved. Examples of the catalyst include a 2-alkyl-4-methylimidazole compound, an imidazole compound such as a 2-alkyl-4-ethylimidazole compound and a 2-phenylimidazole compound, boron tin fluoride and zinc boron fluoride A metal boron fluoride compound; A metal octoate compound consisting of boron trifluoride and tin octoate and zinc octoate, and may include at least one of the group consisting of an imidazole compound and at least one of boron trifluoride . The catalyst may contain 0.1 to 2.0 parts by weight, preferably 0.3 to 1.0 part by weight, based on 100 parts by weight of the epoxy thermosetting resin. If the amount of the catalyst is less than 0.1 parts by weight, the problem of heat resistance may occur. If the amount of the catalyst is more than 2.0 parts by weight, a problem of adhesion may occur.

The silane coupling agent may be an epoxy group-containing silane coupling agent, an amino group-containing silane coupling agent, a vinyl tri (C1 to C3 alkoxy) silane containing silane coupling agent, a 3-methacryloxypropylmethyldimethoxysilane- - methacryloxypropyltrimethoxysilane-containing silane coupling agent. The amount to be used may be 10 to 35 parts by weight, preferably 12 to 25 parts by weight, based on 100 parts by weight of the epoxy thermosetting resin. If the amount of the silane coupling agent is less than 10 parts by weight, the effect of increasing the adhesive strength may not be exhibited. If the amount exceeds 35 parts by weight, other properties such as heat resistance may be deteriorated.

As the above-mentioned additives, an ultraviolet protective agent, a heat resistance enhancer, and the like may be further used.

The thickness of the second adhesive layer 40 may be 5 탆 to 40 탆, preferably 5 탆 to 25 탆. If the thickness of the second adhesive layer 40 is less than 5 mu m, a problem of insufficient filling of the step between the metal foil layer and the circuit may occur. If the thickness is more than 40 mu m, the FPCB of the present invention may have an unnecessary thickness increase , And a burr may occur during a drilling process.

Meanwhile, the coverlay film 200 of the present invention may further include a protective substrate layer 50 laminated on one surface of the second adhesive layer 40.

The protective substrate layer 50 is laminated on one surface of the second adhesive layer 40 so that the second adhesive layer 40 as a detachable release film prevents foreign matter contamination from the external environment and prevents the second adhesive The surface of the layer 40 can be protected.

The protective substrate layer 50 may include at least one of a paper film or a plastic resin film. In other words, the protective substrate layer 50 may be a paper film coated with a polyethylene, polypropylene or methylpentene copolymer resin or a polyethylene, a polypropylene, a methylpentene copolymer resin, a polyethylene terephthalate A plastic resin film such as a phthalate resin, a polyethylene naphthalate resin, or the like.

The thickness of the protective substrate layer 50 is not particularly limited, but may be in the range of 6 탆 to 200 탆 in consideration of the processability and manufacturing qualities of the FPCB, and preferably 12 탆 to 200 탆 based on a paper film, It may be 6 mu m to 75 mu m. If the thickness of the protective substrate layer 50 is less than 6 mu m, there may occur a problem that processability due to the thin film is lowered. If the thickness exceeds 200 mu m, unnecessary decrease in the diameter and increase in thickness and weight of the coverlay film 200 There may be a problem.

In the transparent coverlay film of the present invention, the transparent adhesive layer and / or the second adhesive layer preferably have a light transparency of 91% or more, preferably 93% or more, and a glass transition temperature (Tg) Or more, preferably 140 to 200 ° C.

In the transparent coverlay film of the present invention, the adhesive strength of the transparent adhesive layer and / or the second adhesive layer may be 0.6 kg / cm ² or more, preferably 0.7 kg / cm ^{2 or} more.

The transparent coverlay film of the present invention composed of the transparent base layer and the transparent adhesive layer may have a light transparency of 90% or more, preferably 91% or more, more preferably 92% or more of optical transparency based on a wavelength of 500 nm.

Next, the present invention provides an FPCB including the coverlay film.

The FPCB (Flexible printed circuit board (FPCB)) is an electronic component developed by reducing the size and weight of an electronic product. The FPCB including the coverlay film of the present invention has low elasticity and is excellent in rigidity as well as flexibility.

The FPCB of the present invention is used as a core component of an electronic product such as a mobile phone, a camera, a notebook, a wearable device, a computer and a peripheral device, a mobile communication terminal, a video and audio device, a camcorder, a printer, a DVD player, Equipment, medical equipment, and preferably at least one of a mobile phone, a camera, a notebook, and a wearable device.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be understood that various changes and modifications may be made without departing from the scope of the present invention. For example, each component specifically illustrated in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

The present invention will now be described more specifically with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

[Example]

Preparation Example 1: Preparation of polyimide film

200 mL of N-methyl-2-pyrrolidone (NMP) was added to a 500-mL two-neck round bottom flask substituted with nitrogen gas, and the dianhydride represented by the following formula 1-1 and the di And the reaction was carried out at 24 to 25 ° C for 24 hours to prepare polyamic acid solution of polyamic acid.

Next, 0.25 mol of anhydrous acetic acid and 0.25 mol of pyridine were added to the solution, and the mixture was coated on a glass substrate. Imidization reaction was then carried out to obtain 93.5 Polyimide having a light transmittance of ~94% was synthesized.

[Formula 1-1]

이다.In Formula 1-1, R < ₁ >

to be.

[Formula 2-1]

H ₂ NR ₂ -NH ₂

이다.In formula (2-1), R ₂ is

to be.

Preparation Example 2

A thermoplastic resin, an epoxy resin, a curing agent, a curing accelerator and a filler composition were blended as shown in Table 1 below, and the solution was prepared by dissolving at a temperature of from room temperature to 40 ° C or below.

Classification (parts by weight) Preparation Example 2 Thermoplastic resin 100 Epoxy resin 1 100 Epoxy resin 2 30 Filler 1 40 Filler 2 20 Hardener 40 Hardening accelerator 0.4 * Thermoplastic resin: Acrylonitrile butadiene rubber (NBR) (Nantex, 1072CG)
* Epoxy resin 1: Bisphenol-A type epoxy (Kido Chemical, YD134)
* Epoxy resin 2: O-cresol novolac type epoxy (Kukdo Chemical, YDCN 7P)
* Filler 1: Inorganic filler (H43, Showa Denko)
* Filler 2: phosphine type filler (Clariant, OP930)
* Hardener: amine type hardener (CTN, DDS)
* Curing accelerator: Curing accelerator (Shikoku Chemical, 2MA-OK)

Preparation Examples 3-1 to 3-4: Preparation of transparent adhesive

An epoxy-based thermosetting resin, an acrylic binder resin, a curing agent, a catalyst, a filler and a silane coupling agent were blended as shown in Table 2 below and dissolved at room temperature to 40 ° C or lower to prepare a transparent adhesive.

The optical transparency, the glass transition temperature, and the adhesive strength of each of the manufactured transparent adhesives are shown in Table 2 below.

Classification (parts by weight) Preparation Example 3-1 Preparation Example 3-2 Comparative Preparation Example 3-1 Comparative preparation example 3-2 Epoxy thermosetting resin 100 100 100 100 Acrylic binder resin 47 60 47 47 Silane coupling agent 15 15 40 15 filler 40 40 40 85 Hardener 20 20 20 20 catalyst 0.5 0.5 0.5 0.5 Optical transparency
(Based on 500 nm wavelength) 93.3% 92.5% 90.6% 87.4% Glass transition temperature 142 ° C 140 ° C 123 ℃ 146 ° C Adhesive strength 0.72 kg / cm ² 0.75 kg / cm ² 0.74 kg / cm ² 0.63 kg / cm ²

, 여기서, R₁은 메톡시에틸기이다.
*실란커플링제 : 3-메타크릴옥시프로필트리메톡시실란 함유 실란커플링제
*필러 : 인 타입 필러(phosphine type filler)(클라리언트, OP930)
*경화제 : 아민 타입 경화제(amine type hardener)(CTN, DDS)
*촉매(경화촉진제) : 경화촉진제(시코쿠화학, 2MA-OK)* Epoxy thermosetting resin: O-cresol novolac type epoxy (Kukdo Chemical, YDCN 7P)
* Acrylic binder resin:

, Wherein R < ₁ > is a methoxyethyl group.
Silane coupling agent: 3-methacryloxypropyltrimethoxysilane-containing silane coupling agent
* Filler: phosphine type filler (Clariant, OP930)
* Hardener: amine type hardener (CTN, DDS)
* Catalyst (curing accelerator): Curing accelerator (Shikoku Chemical, 2MA-OK)

Example  One

The transparent adhesive prepared in Preparative Example 3-1 was uniformly coated on one surface of the transparent polyimide film (transparent substrate layer) prepared in Preparative Example 1 using a comma coater and heated at 110 ° C for 3 minutes inline And then heat-treated through an in-line drying oven to form a transparent adhesive layer and semi-cured.

A polyethylene terephthalate (PET) film (SKC, SG31) used as a protective substrate layer having a thickness of 36 mu m was bonded to the surface of the transparent adhesive layer semi-hardened through a heating roller at 65 DEG C under a linear pressure of 6 kg / cm, A transparent coverlay film was produced.

The optical transparency of the low-elastic transparent coverlay film produced was 92.2%.

Example 2

(1) The solution prepared in Preparative Example 2 was uniformly coated on one side of a transparent polyimide film (transparent base layer) prepared in Preparation Example 1 using a comma coater, And then heat-treated through an in-line drying oven to form and dry the first adhesive layer. At this time, the thickness (P ₂ ) of the transparent base layer is 5 탆.

(2) A metal foil layer made of a copper foil (Mitsui, 3EC-3 1/3 oz) was applied to a surface of the dried first adhesive layer on a transparent substrate layer through a heating roller at 60 ° C with a linear pressure of 6 kg / , And heat-treated at 100 DEG C for 200 minutes to cure the first adhesive layer. At this time, the thickness (P ₁ ) of the hardened first adhesive layer is 5 탆.

(3) The transparent adhesive prepared in Preparative Example 3-1 was uniformly coated on the other surface of the transparent base layer and heat-treated at 110 ° C for 3 minutes through an in-line drying oven to form a second adhesive layer And semi-cured. At this time, the thickness (P ₃ ) of the second adhesive layer is 40 탆.

(4) A linear pressure of 6 kg / cm was applied to a polyethylene terephthalate (PET) film (SKC, SG31) used as a protective substrate layer having a thickness of 36 탆, 2 adhesive layer to produce a coverlay film.

Example  3

A coverlay film was produced in the same manner as in Example 2. [ However, the transparent adhesive prepared in Preparation Example 3-2 was used in place of the transparent adhesive prepared in Preparation Example 3-1 in the step (3).

Example  4

A coverlay film was produced in the same manner as in Example 2. [ However, the thickness (P ₂ ) of the transparent base layer in step (1) is 25 μm, the thickness (P ₁ ) of the cured first adhesive layer in step (2) is 20 μm, The thickness (P ₃ ) of the adhesive layer is 5 탆.

Example  5

A coverlay film was produced in the same manner as in Example 4. [ However, the transparent adhesive prepared in Preparation Example 3-3 was used instead of the transparent adhesive prepared in Preparation Example 3-1 in the step (3).

Example  6

A coverlay film was produced in the same manner as in Example 2. [ However, the thickness (P ₂ ) of the transparent base layer in step (1) is 25 μm, the thickness (P ₁ ) of the cured first adhesive layer in step (2) is 5 μm, The thickness (P ₃ ) of the adhesive layer is 40 탆.

Example  7

A coverlay film was produced in the same manner as in Example 6. [ However, the transparent adhesive prepared in Preparation Example 3-2 was used in place of the transparent adhesive prepared in Preparation Example 3-1 in the step (3).

Example  8

A coverlay film was produced in the same manner as in Example 2. [ The thickness (P ₂ ) of the transparent base layer in step (1) is 5 μm, the thickness (P ₁ ) of the cured first adhesive layer in step (2) is 5 μm, The thickness (P ₃ ) of the adhesive layer is 5 탆.

Example 9

A coverlay film was produced in the same manner as in Example 8. [ However, the transparent adhesive prepared in Preparation Example 3-2 was used in place of the transparent adhesive prepared in Preparation Example 3-1 in the step (3).

Example 10

A coverlay film was produced in the same manner as in Example 2. [ However, the thickness (P ₂ ) of the transparent base layer in step (1) is 5 μm, the thickness (P ₁ ) of the cured first adhesive layer in step (2) is 20 μm, The thickness (P ₃ ) of the adhesive layer is 5 탆.

Example 11

A coverlay film was produced in the same manner as in Example 10. [ However, the transparent adhesive prepared in Preparation Example 3-2 was used in place of the transparent adhesive prepared in Preparation Example 3-1 in the step (3).

Comparative Example 1

A coverlay film was produced in the same manner as in Example 2. [ However, in the step (3), the transparent adhesive prepared in Comparative Preparation Example 3-1 was used in place of the transparent adhesive prepared in Preparation Example 3-1.

Comparative Example 2

A coverlay film was produced in the same manner as in Example 2. [ However, in the step (3), the transparent adhesive prepared in Comparative Preparation Example 3-2 was used in place of the transparent adhesive prepared in Preparation Example 3-1.

Comparative Example  3

A coverlay film was produced in the same manner as in Example 4. [ However, in the step (3), the transparent adhesive prepared in Comparative Preparation Example 3-1 was used in place of the transparent adhesive prepared in Preparation Example 3-1.

Comparative Example  4

A coverlay film was produced in the same manner as in Example 4. [ However, in the step (3), the transparent adhesive prepared in Comparative Preparation Example 3-2 was used in place of the transparent adhesive prepared in Preparation Example 3-1.

Comparative Example  5

A coverlay film was produced in the same manner as in Example 2. [ However, the thickness (P ₂ ) of the transparent base layer in step (1) is 25 μm, the thickness (P ₁ ) of the cured first adhesive layer in step (2) is 50 μm, The thickness (P ₃ ) of the adhesive layer is 5 탆.

Comparative Example  6

A coverlay film was prepared in the same manner as in Comparative Example 5. [ However, the transparent adhesive prepared in Preparation Example 3-2 was used in place of the transparent adhesive prepared in Preparation Example 3-1 in the step (3).

Comparative Example 7

A coverlay film was produced in the same manner as in Example 2. [ However, the thickness (P ₂ ) of the transparent base layer in step (1) is 5 μm, the thickness (P ₁ ) of the cured first adhesive layer in step (2) is 1 μm, The thickness (P ₃ ) of the adhesive layer is 70 μm.

Comparative Example 8

A coverlay film was produced in the same manner as in Comparative Example 7. [ However, the solution prepared in Preparative Example 3-2 was used instead of the transparent adhesive prepared in Preparation Example 3-1 in Step (3).

Experimental Example

The coverlay films prepared in the above Examples and Comparative Examples were evaluated on the basis of the following physical property evaluation methods, and the results are shown in Table 3.

(1) Modulus of elasticity

After curing the second adhesive layer prepared in each of the 10 cm x 1 cm sized examples and comparative examples, the elasticity at the time of tensile was measured by applying an adhesive tensile tester at a tensile speed of 50 mm / min.

(2) Peel strength

After removing the protective substrate layer of the coverlay film prepared in each of the Examples and Comparative Examples, a 1oz thick copper foil (Mitsui, 3EC-3) was laminated on the surface of the second adhesive layer and laminated on the surface of the second adhesive layer at 160 DEG C for 60 minutes x 30 kgf , And the adhesive properties of the copper foil and the coverlay film were evaluated by using a peeling test machine.

(3) Soldering heat resistance

After removing the protective substrate layer of the coverlay film prepared in each of the examples and the comparative examples, a 1oz thick copper foil (Mitsui, 3EC-3) was laminated on the surface of the second adhesive layer, (Hot press) under the condition of 30 kgf, and the sample was placed in a molten bath for 10 seconds at a temperature of 260 ° C or higher to observe the appearance of the sample. At this time, the evaluation criteria of soldering heat resistance are as follows.

?: 300 占 폚 or higher /?: 280 to 300 占 폚 /?: 260 to 280 占 폚 / 占: 260 占 폚 or less

(4) Flexural characteristics

The coverlay film prepared in each of the examples and the comparative examples was laminated on a pattern circuit in the form of a 2L type FCCL (Flexible Copper Clad Laminate) (Doosan Electronics, product name: 122000) in accordance with JIS C 6471 8.2, The number of times until the coverlay film was broken after repeated bending was measured at a rate of 175 rpm per minute under a condition of a radius of 0.38 mm.

Coverlay film Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Thickness ratio
((P ₁ + P ₂ ) / P ₃ ) 0.25 0.25 9.0 9.0 0.75 0.75 2.0 The second adhesive layer
Modulus of elasticity (Gpa) 0.7 0.5 0.7 0.5 0.7 0.5 0.7 Peel strength (gf) 1,500 1,600 1,300 1,400 1,800 1,900 800 Soldering heat resistance ◎ ○ ◎ ○ ◎ ○ ◎ Flexural properties (times) 450 550 500 580 350 400 700 Example 9 Example 10 Example 11 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Thickness ratio
((P ₁ + P ₂ ) / P ₃ ) 2.0 5.0 5.0 0.25 0.25 9.0 9.0 The second adhesive layer
Modulus of elasticity (Gpa) 0.5 0.7 0.5 2.1 0.09 2.1 0.09 Peel strength (gf) 900 1,100 1,200 400 350 250 300 Soldering heat resistance ○ ◎ ○ △ X △ X Flexural properties (times) 750 600 650 30 900 35 950 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Thickness ratio
((P ₁ + P ₂ ) / P ₃ ) 15 15 0.086 0.086 The second adhesive layer
Modulus of elasticity (Gpa) 0.7 0.5 0.7 0.5 Peel strength (gf) 1,400 1,450 1,500 1,600 Soldering heat resistance △ △ △ △ Flexural properties (times) 100 150 60 70

As shown in Table 3, it was confirmed that the coverlay film of the example according to the present invention exhibited lower elasticity and excellent bending property than the coverlay film of the comparative example.

Specifically, in Example 1 in which the thickness ratio described in Table 3 was 0.25, the second adhesive layer was formed from the solution prepared in Preparation Example 2, and the second adhesive layer was formed from the solution prepared in Preparation Example 3 Example 2 was prepared in the same manner as in Comparative Example 1 except that the thickness ratio described in Table 3 was 0.25, the second adhesive layer was formed from the solution prepared in Preparation Example 4, and the thickness ratio described in Table 3 was 0.25, It is confirmed that the adhesive strength, the brazing heat resistance and the bending property are superior to those of Comparative Example 2 in which the 2-adhesive layer is formed.

In Example 4, in which the thickness ratio described in Table 3 was 9.0, the second adhesive layer was formed of the transparent adhesive prepared in Preparative Example 3-1, and the fourth adhesive layer was formed of the solution prepared in Preparative Example 3-2, Example 5 in which the thickness ratio described in Table 3 is 9.0, Comparative Example 3 in which the second adhesive layer is formed of the transparent adhesive prepared in Comparative Preparation Example 3-1, and the thickness ratio described in Table 3 are 9.0 It can be confirmed that the adhesive strength, soldering heat resistance and bending property are superior to those of Comparative Example 4 in which the second adhesive layer is formed of the transparent adhesive prepared in Preparation Example 3-2.

Further, in Example 2 in which the thickness ratio described in Table 3 is 0.25, the second adhesive layer is formed of the transparent adhesive of Preparation Example 3-1, and the second adhesive layer is formed of the transparent adhesive of Preparation Example 3-2 In Example 3, the thickness ratio described in Table 3 is 15.0, the Comparative Example 5 in which the second adhesive layer is formed of the transparent adhesive of Preparation Example 3-1, and the transparent adhesive layer of the transparent It can be confirmed that the soldering heat resistance and the bending property are superior to the comparative example 6 in which the second adhesive layer is formed with the adhesive.

In Example 2 in which the thickness ratio described in Table 3 is 0.25, the second adhesive layer is formed of the transparent adhesive of Preparation Example 3-1, and the second adhesive layer is formed of the transparent adhesive of Preparation Example 3-2 In Example 3, the thickness ratios described in Table 3 are 0.086, Comparative Example 7 in which the second adhesive layer is formed of the transparent adhesive of Preparation Example 3-1, and 0.086 in the thickness ratio described in Table 3, It can be confirmed that the soldering heat resistance and the bending property are superior to those of Comparative Example 8 in which the second adhesive layer is formed with the transparent adhesive.

Therefore, the coverlay film of the present invention has lower elastic modulus than that of the conventional coverlay film, so that flexibility can be ensured and a constant rigidity can be obtained. Therefore, the FPCB manufactured with the coverlay film of the present invention has rigidity and flexibility Can be satisfied at the same time.

Claims (22)

A transparent base layer and a transparent adhesive layer on one surface of the transparent base layer,
Wherein the transparent base layer comprises at least one selected from a transparent polyimide (PI) resin, a transparent polyethylene terephthalate (PET) resin and a transparent polyethylene naphthalate (PEN) resin,
Wherein the transparent adhesive layer comprises an acrylic adhesive; The transparent polyimide resin according to claim 1, wherein the transparent polyimide resin
A dianhydride comprising at least one selected from the group consisting of dianhydrides represented by the following formula (1); And a diamine containing at least one selected from the group consisting of a diamine represented by the following formula (2): embedded image and a colorless transparent polyimide resin obtained by imidizing a polyamic acid solution ;
[Chemical Formula 1]

In the formula 1, wherein R ₁ is

,

,

,

,

,

,

,

,

or

Lt;
(2)
H ₂ NR ₂ -NH ₂
In formula (2), R ₂ is

,

,

,

,

,

,

,

or

to be.
The transparent adhesive layer according to claim 1, wherein a first adhesive layer and a metal foil layer are sequentially laminated on the other surface of the bonding surface of the transparent adhesive layer and the transparent base layer,
A metal foil layer, a first adhesive layer, a transparent base layer and a second adhesive layer are laminated in this order,
Wherein the first adhesive layer comprises an opaque adhesive or a transparent adhesive,
And the second adhesive layer comprises a transparent adhesive.
The method of claim 3, wherein the average thickness of the first adhesive layer (P _1), the average thickness of the transparent substrate layer (P ₂₎ and the second average thickness of the adhesive layer (P ₃₎ and is to satisfy the equation (1),
Wherein the second adhesive layer has a modulus of elasticity of 0.1 to 2.0Gpa when cured;
[Equation 1]
0.1? (P ₁ + P ₂ ) / P ₃ ? 9.0
In the above equation (1), P ₃ is a rational number satisfying 5 μm ≦ P ₃ ≦ 40 μm.
The method of claim 3,
The average thickness of the first adhesive layer (P _1), the average thickness of the transparent substrate layer (P ₂₎ and the second average thickness of the adhesive layer (P ₃₎ and is to satisfy the equation (1),
Wherein the second adhesive layer has a modulus of elasticity of 0.5 to 1.5Gpa when cured.
[Equation 1]
0.1? (P ₁ + P ₂ ) / P ₃ ? 9.0
In the above equation (1), P ₃ is a rational number satisfying 5 μm ≦ P ₃ ≦ 40 μm.
The method of claim 3,
Wherein the first adhesive layer is in a cured state and the second adhesive layer is in a semi-cured state.
The method of claim 3, wherein the first adhesive layer comprises an opaque adhesive,
The opaque adhesive may include a thermoplastic resin, an epoxy resin, a filler and a hardener;
And a thermosetting epoxy adhesive.
8. The method of claim 7,
Wherein the thermoplastic resin comprises at least one of acrylonitrile butadiene rubber (NBR) and polyimide resin,
The epoxy resin may be selected from the group consisting of a bisphenol-A type epoxy, a bisphenol-A novolac type epoxy, an O-cresol novolac type epoxy, At least one of a dicycolpentadiene type epoxy and a multi-functional novolac type epoxy,
Wherein the filler comprises at least one of an inorganic filler and a phosphine type filler,
Wherein the hardener comprises at least one of an amine type hardener, a phenol type hardener, and an acid type anhydride type hardener.
The method of claim 3,
The thickness (P ₁ ) of the first adhesive layer is 5 μm to 20 μm, the thickness (P ₂ ) of the transparent base layer is 5 μm to 25 μm and the thickness (P ₃ ) of the second adhesive layer is 5 μm to 40 μm Wherein the low elasticity cover layer film is a low elasticity coverlay film.
8. The method of claim 7,
Wherein the first adhesive layer comprises a thermoplastic polyimide (TPI) resin.
The method of claim 3,
The thickness (P ₁ ) of the first adhesive layer is 1 μm to 10 μm, the thickness (P ₂ ) of the transparent base layer is 5 μm to 25 μm and the thickness (P ₃ ) of the second adhesive layer is 5 μm to 40 μm Wherein the low elasticity cover layer film is a low elasticity coverlay film.
The method of claim 3,
Wherein the metal foil layer comprises a copper foil or an aluminum foil,
Wherein the metal foil layer has a thickness of 2 to 40 占 퐉.
The method according to claim 1,
And a protective substrate layer laminated on one surface of the second adhesive layer,
Wherein the protective substrate layer has a thickness of 6 to 200 占 퐉.
14. The method of claim 13,
Wherein the protective substrate layer comprises at least one of a paper film and a plastic resin film.
A low-resilience flexible printed circuit board (FPCB) comprising the transparent coverlay film of any one of claims 1 to 12.
16. The method of claim 15,
Wherein the FPCB is used for at least one of a cellular phone, a camera, a notebook, and a wearable device.
(1) forming a transparent base film; And
(2) coating a transparent adhesive on one side of the transparent base film,
The transparent base film is formed of at least one resin selected from transparent polyimide (PI) resin, transparent polyethylene terephthalate (PET) resin and transparent polyethylene naphthalate (PEN) resin,
Wherein the transparent adhesive includes an acrylic adhesive.
(1) forming a transparent base film;
(2) sequentially laminating a first adhesive layer and a metal foil layer on one side of the transparent substrate film; And
(3) laminating a second adhesive layer on the other surface of the transparent base film,
Wherein the first adhesive layer is formed of an opaque adhesive or a transparent adhesive,
The second adhesive layer is formed of a transparent adhesive,
Wherein the transparent substrate layer is formed of at least one resin selected from a transparent polyimide (PI) resin, a transparent polyethylene terephthalate (PET) resin and a transparent polyethylene naphthalate (PEN) resin. Way.
19. The method of claim 18, wherein the average thickness of the first adhesive layer (P _1), the average thickness of the transparent substrate layer (P ₂₎ and the second average thickness of the adhesive layer (P ₃₎ and is to satisfy the equation (1),
Wherein the second adhesive layer has a modulus of elasticity of 0.1 to 2.0Gpa when cured.
[Equation 1]
0.1? (P ₁ + P ₂ ) / P ₃ ? 9.0
In the above equation (1), P ₃ is a rational number satisfying 5 μm ≦ P ₃ ≦ 40 μm.
19. The method of claim 18, wherein the second adhesive layer has a modulus of elasticity of 0.5 to 1.5Gpa during curing.
The method of claim 18, wherein the first adhesive layer is formed of an opaque adhesive,
Wherein the opaque adhesive comprises a thermosetting epoxy resin, the thickness (P ₁ ) of the first adhesive layer is 5 μm to 20 μm, the thickness (P ₂ ) of the transparent base layer is 5 μm to 25 μm, (P ₃₎ is 5㎛ ~ 40㎛ a low elastic transparent coverlay film method, characterized in that.
19. The method of claim 18,
Wherein the first adhesive layer comprises thermoplastic polyimide (TPI) resin, the thickness (P ₁ ) of the first adhesive layer is 1 탆 to 10 탆, the thickness (P ₂ ) And the thickness (P ₃ ) of the second adhesive layer is 5 탆 to 40 탆.

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