TWI715276B - Flexible photo imageable coverlay film, flexible printed circuit board having the same and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a flexible photosensitive development type cover film and a preparation method thereof, and relates to a flexible photosensitive development type cover film that not only has excellent developability, but also has excellent plugging properties and bending moldability, and a preparation method thereof.

Description

Flexible photosensitive developing type cover film, flexible printed circuit board and preparation method thereof

The present invention relates to a flexible photosensitive developable cover (FPIC) film and a preparation method thereof, and relates to a flexible photosensitive developable cover film that not only has excellent developability, but also has excellent hole plugging and bendability And its preparation method.

Recently, with the trend toward integration, miniaturization, thinning, high density, and high bending of electronic products, the need for printed circuit boards (PCBs) that can be easily built into narrower spaces has increased. In response to this market demand, a flexible printed circuit board (FPCB) that can be miniaturized, increased in density, and has repeated bendability has been developed. Due to the technological development of smart phones, portable mobile electronic devices (smart watches, smart glasses, etc.), the use of such flexible printed circuit boards has increased sharply and their demand is increasing day by day.

Generally, a flexible printed circuit board is prepared by a method of forming a flexible copper clad laminate with copper foil layers formed on both sides or one side of an insulating base film having high heat resistance and high flexibility, such as polyimide (polyimide) (Flexible Copper Clad Laminate) After laminating the dry film, the circuit pattern is formed by exposure, development, and etching in sequence, and the outer side (≒the surface where the circuit pattern is formed) and the coverlay film are temporarily joined , And use a hot press to bond.

The cover film for the flexible printed circuit board is used to ensure the insulation reliability of the flexible printed circuit board or to protect the circuit pattern formed on the flexible printed circuit board. The usually used cover film consists of an adhesive and a base film laminated on one side of the adhesive. In order to exert stable performance for flexible printed circuit boards, it is widely used as an adhesive for cover films directly bonded to flexible printed circuit boards. A bonding agent with epoxy resin as the main component, which has good durability and chemical resistance. For example, Korean Patent Application No. 2014-0084415 discloses a non-halogen fast-curing adhesive composition and a cover film using it, and Korean Patent Application No. 2012-0117438 discloses a method for manufacturing a flexible printed circuit board. In the cover film of the adhesive composition as described above, the flexibility is not ensured due to excessive rigidity. Therefore, a flexible printed circuit board including the cover film is manufactured, and there are cases where parts are packaged in portable devices such as wearable devices and smartphones. The problem of reduced processability and reliability.

In addition, in order to improve the physical properties of the cover film, the adhesive that constitutes the cover film contains various components in addition to epoxy resin, thereby developing a cover film for improving physical properties such as flexibility. However, the electronic equipment market using flexible printed circuit boards is becoming thinner and requires higher fine pitch and flexible characteristics than before. The conventional cover film cannot meet the above needs (needs) part.

On the other hand, in addition to the cover film, products used to ensure the insulation reliability of the flexible printed circuit board or to protect the circuit pattern formed on the flexible printed circuit board also have a liquid-type photosensitive solder resist (PSR: photosensitive solder resist). resist). However, when a liquid-type photosensitive solder resist is used for a flexible printed circuit board, that is, hole plugging is poor, and bendability is significantly reduced.

In addition to cover films, products that can be used to ensure insulation reliability of flexible printed circuit boards or to protect circuit patterns formed on flexible printed circuit boards also have dry film solder resist (DFSR: Dry Film Solder Resist). However, the dry film solder resist has the problem of being very expensive and significantly lowering the bending formability.

Therefore, it is necessary to develop products that can replace the conventional cover film and meet the market demand of electronic equipment using flexible printed circuit boards.

The present invention was made in view of the above-mentioned problems, and its object is to provide a flexible photosensitive developable cover film that not only has excellent developability, but also has excellent plugging properties and bending moldability, and a method for producing the same.

In addition, the object of the present invention is to provide a flexible photosensitive developable cover film having excellent heat resistance, flexibility, adhesion, and chemical resistance, and a preparation method thereof.

To solve the above-mentioned problems, the flexible photosensitive developable cover film of the present invention includes The photosensitive adhesive layer, the photosensitive adhesive layer includes a cured product of a photosensitive adhesive resin, the cured product is a cured product in a B-stage state, and the photosensitive adhesive resin includes a polyimide resin, a thermosetting resin, and The polyurethane resin is a reaction product of a mixture of polycarbonate diol, ring group-containing diisocyanate, carboxyl group-containing diol compound, and hydroxyl group-containing acrylate, and may have alkali solubility and photocurability.

In a preferred embodiment of the present invention, the polyurethane resin may contain a methacrylate component in an amount of 10% by weight or less.

In a preferred embodiment of the present invention, the number average molecular weight (Mn) of the polycarbonate diol may be 500-1100.

In a preferred embodiment of the present invention, the ring group-containing diisocyanate may include a compound represented by the following chemical formula 6.

In the above chemical formula 6, D is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -, R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ are each independently -H or a C1-C5 alkyl group.

In a preferred embodiment of the present invention, the carboxyl group-containing diol compound may include a compound represented by the following Chemical Formula 7.

In the above chemical formula 7, E, F and G are each independently -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -, R ₁₅ is a C1-C5 alkyl group.

In a preferred embodiment of the present invention, the hydroxyl-containing acrylate may include a compound represented by the following Chemical Formula 8.

In the above chemical formula 8, J is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -.

In a preferred embodiment of the present invention, the polyurethane resin may be a reactant containing a mixture of substances, that is, relative to 100 parts by weight of polycarbonate diol, containing 55 to 103 parts by weight of ring group-containing diisocyanate , 17 to 33 parts by weight of carboxyl group-containing diol compound and 6 to 13 parts by weight of hydroxyl group-containing acrylate.

In a preferred embodiment of the present invention, the viscosity of the polyurethane resin may be 1100~5000 cPs (25°C).

In a preferred embodiment of the present invention, the polyimide resin may have alkali solubility and non-photocurable properties.

In a preferred embodiment of the present invention, with respect to 100 parts by weight of the polyimide resin, the photosensitive adhesive resin may include 318-593 parts by weight of polyurethane resin and 39-73 parts by weight of thermosetting resin.

In a preferred embodiment of the present invention, the photosensitive adhesive resin may further include one or more selected from acrylic oligomer resin, photoinitiator, and solvent.

In a preferred embodiment of the present invention, the thickness of the photosensitive adhesive layer may be 10-40 μm.

In a preferred embodiment of the present invention, the flexible photosensitive developable cover film of the present invention may further include: a base film laminated on one side of the photosensitive adhesive layer; and a release film laminated on the other side of the photosensitive adhesive layer one side.

On the other hand, the preparation method of the flexible photosensitive developable cover film of the present invention includes: the first step is to prepare photosensitive by mixing polyimide resin, polyurethane resin, thermosetting resin, acrylic oligomer resin, photoinitiator and solvent. The second step is to apply the photosensitive adhesive resin to one side of the base film, and dry to form a photosensitive adhesive layer on one side of the base film. The polyurethane resin may include polycarbonate diol, A reactant of a mixture of cyclic diisocyanate, carboxyl-containing diol compound, and hydroxyl-containing acrylate.

Furthermore, the flexible printed circuit board of the present invention may include the flexible photosensitive development type cover film as described above.

Moreover, the flexible printed circuit board of the present invention can be used in at least one of mobile phones, cameras, notebook computers, and wearable devices.

When referring to the compound of the present invention, the "*" mark refers to a chemical binding site.

In the terms used in the present invention, "B-stage state" refers to a semi-cured state, specifically, an intermediate state in the curing reaction process of a substance.

In addition, in the terminology used in the present invention, "resin" may be an amorphous solid or semi-solid formed of an organic compound and its derivatives, and may have a polymer form, a film form, or a formed body form.

The flexible photosensitive developable cover film and the preparation method thereof of the present invention not only have excellent developability, but also have excellent plugging properties and bending formability.

Moreover, the flexible photosensitive development type cover film and the preparation method thereof of the present invention also have excellent heat resistance, flexibility, adhesion and chemical resistance.

10: Photosensitive adhesive layer

20: Basement membrane

30: Release film

Fig. 1 is a cross-sectional view of a flexible photosensitive developing type cover film according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, so that those skilled in the art to which the present invention belongs can easily implement the present invention. The present invention can be implemented in various different forms and is not limited to the embodiment described here. In the drawings, in order to clearly illustrate the present invention, parts irrelevant to the description are omitted, and the same or similar structural elements are given the same reference numerals throughout the specification.

The Flexible Photo Imageable Coverlay (FPIC, Flexible Photo Imageable Coverlay) film of the present invention includes a photosensitive adhesive layer containing a cured product of a photosensitive adhesive resin. In this case, the cured product may be a cured product in a B-stage state.

The photosensitive adhesive resin of the present invention may include polyimide resin, thermosetting resin and polyurethane resin.

As described above, the photosensitive adhesive resin of the present invention includes not only polyurethane resin and polyimide resin, but also thermosetting resin. As described above, since it contains polyurethane resin, polyimide resin and thermosetting resin, it has excellent development Technical characteristics such as flexibility, plugging, bending formability, heat resistance, bending, adhesion and chemical resistance. Specifically, in the photosensitive adhesive resin of the present invention, an appropriate amount of specific polyurethane resin is used, and based on the flexibility of the polyurethane resin, the bending formability and bendability become excellent. By using an appropriate amount of specific polyurethane resin The imine resin, based on the heat resistance of the polyimide resin, makes up for the weak heat resistance of the urethane group. In addition, based on a specific thermosetting resin and a specific acrylic oligomer resin that can be additionally included, it has excellent adhesion and chemical resistance.

In addition, relative to 100 parts by weight of the polyimide resin, the photosensitive adhesive resin of the present invention may contain 318 to 593 parts by weight of polyurethane resin, preferably, 364 to 547 parts by weight of polyurethane resin, more preferably, It may contain 409 to 501 parts by weight of polyurethane resin. If it contains less than 318 parts by weight of polyurethane resin, it may have the problem of reduced alkali resistance. If it contains more than 593 parts by weight of polyurethane resin, it may have the problem of reduced resolution.

In addition, with respect to 100 parts by weight of polyimide, the photosensitive adhesive resin of the present invention may contain 39 to 73 parts by weight of thermosetting resin, preferably, may contain 44 to 68 parts by weight of thermosetting resin, and more preferably, The thermosetting resin containing 50 to 62 parts by weight, if less than 39 parts by weight of the thermosetting resin is contained, may have the problem of reduced heat resistance, and if the thermosetting resin is contained more than 73 parts by weight, the problem of the phenomenon speed may be reduced.

First, the polyimide resin of the present invention may include a copolymer of a diamine compound and an anhydride compound.

In addition, the polyimide resin may have alkali solubility and non-photocurability.

Moreover, the viscosity of the polyimide resin can be 100~600cPs (25°C), preferably, The viscosity of the polyimide resin can be 200~400cPs (25℃). If the viscosity of the polyimide resin is less than 100cPs (25℃), it may have the problem of poor film formation. If the viscosity of the polyimide resin is If it is greater than 600 cPs (25° C.), the resolution may decrease.

Moreover, the acid value of the polyimide resin can be 100~250mgKOH/g, preferably, the acid value of the polyimide resin can be 150~200mgKOH/g, if the acid value of the polyimide resin If it is less than 100 mgKOH/g, the resolution may be reduced. If the acid value of the polyimide resin is greater than 250 mgKOH/g, it may have a problem that the development speed cannot be controlled.

In addition, the diamine compound and the acid anhydride compound can be contained in a weight ratio of 1:0.27 to 1:0.52. Preferably, the diamine compound and the acid anhydride compound can be contained in a weight ratio of 1:0.31 to 1:0.48. Preferably, the diamine compound and the acid anhydride compound can be in a weight ratio of 1:0.35 to 1:0.44. If the weight ratio exceeds the above range, it may have a problem of poor film appearance.

The diamine compound may include one or more selected from polyetheramine and the compound represented by the following Chemical Formula 1, and preferably, may include polyetheramine and the compound represented by the following Chemical Formula 1.

In this case, the compound represented by the above Chemical Formula 1 may include the compound represented by the following Chemical Formula 1-1.

When the diamine compound contains the compound represented by the polyetheramine and the above chemical formula 1, relative to 100 parts by weight of the polyetheramine, it may contain 0.72 to 1.36 parts by weight of the compound represented by the above chemical formula 1, and preferably, may contain 0.83 to 1.25 parts by weight of the compound represented by the above chemical formula 1, more preferably, may contain 0.93 to 1.15 parts by weight of the compound represented by the above chemical formula 1, if it contains less than 0.72 parts by weight of the compound represented by the above chemical formula 1, then There may be a problem of reduced resolution, and if it contains more than 1.36 parts by weight of the compound represented by the above chemical formula 1, there may be a problem that the development speed cannot be controlled.

On the other hand, the diamine compound may further include a compound represented by the following Chemical Formula 2. In this case, relative to 100 parts by weight of the polyetheramine, 5.88 to 11.0 parts by weight of the compound represented by the following chemical formula 2 may be contained, and preferably, 6.73 to 10.1 parts by weight of the compound represented by the following chemical formula 2 may be contained The compound, more preferably, may contain 7.57 to 9.26 parts by weight of the compound represented by the following chemical formula 2. If it contains less than 5.88 parts by weight of the compound represented by the following chemical formula 2, it may have a problem of reduced surface hardness. More than 11.0 parts by weight of the compound represented by the following chemical formula 2 may have a problem of reduced resolution.

。 In the above chemical formula 2, A and B are

.

In addition, in the above chemical formula 2, R ₁ and R ₂ are each independently -H or a C1-C5 alkyl group, preferably, a C1-C3 alkyl group.

Furthermore, the polyetheramine of the present invention may include a compound represented by the following chemical formula 3.

In the above chemical formula 3, R ₁ and R ₂ are each independently -H or a C1-C5 alkyl group, preferably, a C1-C3 alkyl group.

Moreover, in the above chemical formula 3, m can be 5-20, preferably, m can be 8-17, more preferably, m can be a rational number satisfying 10-15, and l+n can be 3-9, preferably , L+n may be 4-8, more preferably, l+n may be a rational number satisfying 5-7.

Also, the amine hydrogen equivalent weight of the compound represented by the above chemical formula 3 may be 102 to 162 g/eq, preferably, the amine hydrogen equivalent weight of the compound represented by the above chemical formula 3 may be 112 to 152 g/eq, more Preferably, the amine hydrogen equivalent of the compound represented by the above Chemical Formula 3 may be 122 to 142 g/eq.

And, the molecular weight (molecular weight) of the compound represented by the above Chemical Formula 3 may be 900 or less.

Also, the pH of the compound represented by the above chemical formula 3 may be 8.19 to 15.21, preferably, the pH of the compound represented by the above chemical formula 3 may be 9.36 to 14.04, more preferably, the pH of the compound represented by the above chemical formula 3 may be 10.53~12.87.

And, the viscosity of the compound represented by the above chemical formula 3 may be 95~145cSt (20°C), preferably, the viscosity of the compound represented by the above chemical formula 3 may be 100~140cSt (20°C), more preferably, The viscosity of the compound represented by the above Chemical Formula 3 may be 110~130 cSt (20°C).

Also, the melting point of the compound represented by the above Chemical Formula 3 may be 17-28°C, preferably, the melting point of the compound represented by the above Chemical Formula 3 may be 20-25°C.

And, the density of the compound represented by the above chemical formula 3 may be 0.72~1.35g/ml, preferably, the density of the compound represented by the above chemical formula 3 may be 0.82~1.25g/ml, more preferably, the density of the compound represented by the above The density of the compound represented by Chemical Formula 3 may be 0.93-1.14 g/ml.

On the other hand, the acid anhydride compound may include one or more selected from the compound represented by the following chemical formula 4 and the compound represented by the following chemical formula 5. Preferably, the acid anhydride compound may include the compound represented by the following chemical formula 4 and The compound represented by the following chemical formula 5.

In this case, the compound represented by the above-mentioned chemical formula 4 and the compound represented by the above-mentioned chemical formula 5 can be contained in a weight ratio of 1:0.09 to 1:0.18, preferably, it can be contained in a weight ratio of 1:0.11 to 1:0.17 The compound represented by the above chemical formula 4 and the compound represented by the above chemical formula 5, more preferably, can contain the compound represented by the above chemical formula 4 and the compound represented by the above chemical formula 5 in a weight ratio of 1:0.12 to 1:0.16, if If the weight ratio is less than 1:0.09, the developing speed may be reduced. If the weight ratio is greater than 1:0.18, the film may have poor appearance due to the decrease in viscosity.

Thereafter, the thermosetting resin of the present invention may include epoxy resin, preferably, may include a ring selected from the group consisting of bisphenol epoxy resin, biphenyl epoxy resin, naphthalene epoxy resin, fluorene epoxy resin, and phenol phenolic epoxy resin. One or more of an oxy resin, a cresol novolac epoxy resin, a trihydroxyphenylmethane type epoxy resin, and a tetraphenylmethane epoxy resin, and more preferably, may contain a cresol novolac epoxy resin.

Next, the polyurethane resin of the present invention can be prepared by containing polycarbonate diol, cyclo group-containing diisocyanate (diisocyanate), carboxy group-containing diol compound, and hydroxyl group-containing ) And react to generate acrylate.

In addition, the polyurethane resin may have alkali solubility and photocurability.

In addition, the viscosity of the polyurethane resin of the present invention may be 1100 to 5000 cPs (25° C.), preferably, the viscosity of the polyurethane resin of the present invention may be 1200 to 4000 cPs (25° C.), more preferably, the viscosity of the polyurethane resin of the present invention It can be 1400~3500cPs (25℃), if the polyurethane tree of the present invention If the viscosity of the grease is less than 1100 cPs (25° C.), the resolution may be reduced. If the viscosity of the polyurethane resin of the present invention is greater than 5000 cPs (25° C.), the development speed may be reduced.

In addition, the polyurethane resin of the present invention may contain less than 10 weight percent of methacrylate components, preferably, it may contain 3 to 8 weight percent of methacrylate components, and more preferably, it may contain 4 to 6 weight percent. If the percentage of the methacrylate component contains more than 10% by weight of the methacrylate component, the phenomenon speed may decrease.

On the other hand, the number average molecular weight (Mn) of the polycarbonate diol may be 500 to 1100, preferably, the number average molecular weight (Mn) of the polycarbonate diol may be 600 to 1000, more preferably, the polycarbonate The number average molecular weight (Mn) of the diol can be 700 to 900.

And, the diisocyanate including a ring group may include a compound represented by the following Chemical Formula 6.

In the above chemical formula 6, D is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -, preferably, D is -CH ₂ -, -CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ -.

In the above chemical formula 6, R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ are each independently -H or a C1-C5 alkyl group, preferably, R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ are each independently -H or a C1-C3 alkyl group.

And, the carboxyl group-containing diol compound may include a compound represented by Chemical Formula 7 below.

In the above chemical formula 7, E, F and G are each independently -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -, preferably, each independently is -CH ₂ -, -CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ -.

In the above chemical formula 7, R ₁₅ is a C1-C5 alkyl group, preferably, R ₁₅ is a C1-C3 alkyl group.

And, the hydroxyl group-containing acrylate may include a compound represented by the following Chemical Formula 8.

In the above chemical formula 8, J is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -, preferably, J is -CH ₂ -, -CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ -.

Furthermore, relative to 100 parts by weight of polycarbonate diol, the polyurethane resin of the present invention may contain 55 to 103 parts by weight of cyclic group-containing diisocyanate, and preferably, may contain 62 to 95 parts by weight of cyclic group-containing diisocyanate. The isocyanate, more preferably, may contain 70 to 87 parts by weight of a diisocyanate containing a ring group.

And relative to 100 parts by weight of the polycarbonate diol, the polyurethane resin of the present invention may contain 17 to 33 parts by weight of the carboxyl group-containing diol compound, preferably 20 to 31 parts by weight of the carboxyl group-containing diol compound More preferably, it may contain 22-28 parts by weight of the carboxyl-containing diol compound. If it contains less than 17 parts by weight of the carboxyl-containing diol compound, it may have the problem of reduced development speed. If it contains more than 33 parts by weight of the carboxyl group-containing diol compound, there may be a problem of reduced surface hardness.

In addition, relative to 100 parts by weight of polycarbonate diol, the polyurethane resin of the present invention may contain 6-13 parts by weight of hydroxyl-containing acrylate, preferably, 7-12 parts by weight of hydroxyl-containing acrylate, More preferably, it may contain 8 to 11 parts by weight of hydroxyl-containing acrylate.

On the other hand, the photosensitive adhesive layer of the present invention may further include one or more selected from acrylic oligomer resins, photoinitiators, and solvents, and preferably, may also include acrylic oligomer resins and photoinitiators.

The acrylate oligomer resin of the present invention may include: a first acrylic oligomer resin, which has water solubility and photocurability; and a second acrylic oligomer resin, which is bonded to the carboxyl group of the polyimide resin. Polyimide resin imparts ultraviolet (UV) reactivity.

In addition, the first acrylic oligomer resin may be a difunctional acrylic oligomer resin, and the second acrylic oligomer may be an acrylic oligomer resin containing an isocyanate group.

Specifically, the first acrylic oligomer resin may be an epoxy acrylate that includes an -OH group in the molecular structure while opening the epoxy ring.

Also, the weight average molecular weight (Mw) of the first acrylic oligomer resin may be 500 to 1000, preferably, the weight average molecular weight of the first acrylic oligomer resin may be 600 to 900, and more preferably, the first acrylic low The weight average molecular weight of the polymer resin can be 650-850.

In addition, the viscosity of the first acrylic oligomer resin may be 1000~2000cPs (25°C), preferably, the viscosity of the first acrylic oligomer resin may be 1100~1900cPs (25°C), more preferably, the first acrylic resin The viscosity of the oligomer resin can be 1300~1700cPs (25℃).

And, the refractive index of the first acrylic oligomer resin may be 1.18~1.79 nD ₂₅ , preferably, the refractive index of the first acrylic oligomer resin may be 1.33~1.64 nD ₂₅ , more preferably, The refractive index of an acrylic oligomer resin can be 1.4~1.53 nD ₂₅ .

In addition, the specific gravity of the first acrylic oligomer resin may be 0.8 to 1.6 (25° C.), preferably, the specific gravity of the first acrylic oligomer resin may be 0.9 to 1.5 (25° C.), more preferably , The specific gravity of the first acrylic oligomer resin can be 1.0~1.4 (25°C).

And, the acid value of the first acrylic oligomer resin can be 6.4~12.4mgKOH/g, Preferably, the acid value of the first acrylic oligomer resin may be 7.4 to 11.4 mgKOH/g, and more preferably, the acid value of the first acrylic oligomer resin may be 8.4 to 10.4 mgKOH/g.

On the other hand, the second acrylic oligomer resin may have self-polymerization and photopolymerization properties by including a diisocyanate group.

In addition, the second acrylic oligomer resin may include 9.9 to 15.9% of diisocyanate groups, preferably, may include 10.9 to 14.9% of diisocyanate groups, and more preferably, may include 11.9 to 13.9% of diisocyanate groups.

In addition, the viscosity of the second acrylic oligomer resin may be 7000~11000 cPs (25°C), preferably, the viscosity of the second acrylic oligomer resin may be 8000~10000 cPs (25°C), more preferably, the second acrylic acid The viscosity of the oligomer resin can be 8500-9500cPs (25℃).

In addition, the first acrylic oligomer resin and the second acrylic oligomer resin can be included in a weight ratio of 1:0.11 to 1:0.22. Preferably, the first acrylic oligomer resin can be included in a weight ratio of 1:0.13 to 1:0.20. The material resin and the second acrylic oligomer resin, more preferably, can contain the first acrylic oligomer resin and the second acrylic oligomer resin in a weight ratio of 1:0.14 to 1:0.19, if the weight ratio is less than 1:0.11 , This may have the problem of reduced surface hardness. If the weight ratio is greater than 1:0.22, the development speed may be reduced.

In addition, with respect to 100 parts by weight of polyimide resin, the photosensitive adhesive resin of the present invention may contain 117 to 218 parts by weight of the first acrylic oligomer resin, preferably, may contain 133 to 201 parts by weight of the first acrylic oligomer resin. The acrylic oligomer resin, more preferably, may contain 150 to 185 parts by weight of the first acrylic oligomer resin. If it contains less than 117 parts by weight of the first acrylic oligomer resin, the resolution may decrease. If it contains more than 218 parts by weight of the first acrylic oligomer resin, there may be a problem of product curl.

In addition, with respect to 100 parts by weight of polyimide resin, the photosensitive adhesive resin of the present invention may contain 19 to 37 parts by weight of the second acrylic oligomer resin, and preferably, may contain 22 to 34 parts by weight of the second acrylic oligomer resin. The acrylic oligomer resin, more preferably, may contain 24 to 31 parts by weight of the second acrylic oligomer resin. If it contains less than 19 parts by weight of the second acrylic oligomer resin, the surface hardness may decrease. If it contains more than 37 parts by weight of the second acrylic oligomer resin, it may have a problem of reduced resolution.

The photoinitiator of the present invention may include one or more selected from hydroxyketone-based photoinitiators and oxime-based photoinitiators, and preferably, may include hydroxyketone-based photoinitiators.

And, relative to 100 parts by weight of the polyimide resin, the photosensitive adhesive resin of the present invention may contain 9.8 to 18.4 parts by weight of photoinitiator, preferably, it may contain 11.3 to 17.0 parts by weight of photoinitiator, more preferably It may contain 12.7 to 15.6 parts by weight of photoinitiator. If it contains less than 9.8 parts by weight of photoinitiator, it may have the problem of reduced developability caused by uncuring. If it contains more than 18.4 parts by weight of photoinitiator, then There may be a problem of reduced resolution caused by over-curing.

On the other hand, the photosensitive adhesive resin of the present invention can satisfy the following relational expression 1, and preferably, can satisfy the following relational expression 2.

Relation 1 C<A<B

In the above-mentioned relational formula 1, A represents the content of the polyimide resin, B represents the content of the polyurethane resin, and C represents the content of the photoinitiator resin.

Relation 2 A+C<B

In the aforementioned relational formula 2, A represents the content of the polyimide resin, B represents the content of the polyurethane resin, and C represents the content of the photoinitiator resin.

If the photosensitive adhesive resin of the present invention cannot satisfy the above-mentioned relational expressions 1 and 2, it may have problems of reduced resolution and alkali resistance.

In addition, the photosensitive adhesive resin of the present invention can satisfy the following relational expression 3.

Relation 3 C<D<A<B

In the above relation 3, A represents the content of polyimide resin, B represents the content of polyurethane resin, C represents the content of photoinitiator, and D represents the content of thermosetting resin.

If the photosensitive adhesive resin of the present invention cannot satisfy the above-mentioned relational formula 3, it may have a problem of poor alkali resistance.

Furthermore, the photosensitive binder resin of this invention may also contain one or more types selected from filler, pigment, additive, and flame-retardant particle.

On the other hand, as described below with reference to FIG. 1, as described above, the flexible photosensitive developable cover film of the present invention may include a photosensitive adhesive layer 10. In this case, the thickness of the photosensitive adhesive layer 10 may be 10-40 μm, preferably, the thickness of the photosensitive adhesive layer 10 may be 15-35 μm, more preferably, the thickness of the photosensitive adhesive layer 10 may be 20-30 μm If the thickness of the photosensitive adhesive layer 10 is less than 10 μm, it may have a problem of poor circuit embedding. If the thickness of the photosensitive adhesive layer 10 is greater than 40 μm, it may have a problem of reduced resolution caused by reduced light transmission characteristics.

The flexible photosensitive developable cover film of the present invention may further include a base film 20 laminated on one side of the photosensitive adhesive layer 10. The base film 20 is a film that functions as a film for the photosensitive adhesive layer 10 and transmits light, and may include one selected from polypropylene (PP) and polyethylene terephthalate (PET) Above, preferably, optical polyterephthalic acid may be contained. In addition, the thickness of the base film 20 may be 15-50 μm, preferably, the thickness of the base film 20 may be 25-50 μm. If the thickness of the base film 20 is less than 15 μm, there may be workability problems. If the thickness of the base film 20 is If it is larger than 50 μm, there may be a problem of poor ultraviolet light transmission characteristics.

The flexible photosensitive developable cover film of the present invention may further include a release film 30 laminated on the other side of the photosensitive adhesive layer 10. The release film 30 is the part taken out when the photosensitive adhesive layer 10 of the flexible photosensitive developable cover film of the present invention is attached to the flexible printed circuit board during use, and may include polyterephthalic acid, preferably, may include release polyterephthalate Formic acid. In addition, the thickness of the release film 30 may be 15-50 μm, preferably, the thickness of the release film 30 may be 25-50 μm. If the thickness of the release film 30 is less than 15 μm, the photosensitive adhesive layer 10 may have poor protection. If the thickness of the release film 30 is greater than 50 μm, it may have a problem of poor bending.

Furthermore, the preparation method of the flexible photosensitive and developable cover film of the present invention includes a first step and a second step.

First, in the first step of the method for preparing the flexible photosensitive developable cover film of the present invention, the photosensitive adhesive resin can be prepared by mixing polyimide resin, polyurethane resin, thermosetting resin, acrylic oligomer resin, photoinitiator and solvent. In this case, the solvent in the first step can be an organic solvent, and preferably, it can contain a solvent selected from methyl ethyl ketone (MEK), toluene, N,N-dimethylacetamide (DMAc), N-methyl One or more of nylpyrrolidone (NMP), cyclohexanone, and methylcyclohexanone, and more preferably, may include methyl ethyl ketone. And, the acrylic oligomer resin may include the first acrylic oligomer resin and The second acrylic oligomer resin.

Next, in the second step of the method for preparing the flexible photosensitive and developable cover film of the present invention, the photosensitive adhesive resin prepared in the first step is coated on one side of the base film, and a photosensitive adhesive layer is formed on one side of the base film by drying.

The second step of drying is performed at a temperature of 100-230°C, preferably at a temperature of 130-200°C, for 1-10 minutes, preferably for 3-7 minutes.

Moreover, the preparation method of the flexible photosensitive developable cover film of the present invention may further include a third step. The third step of the preparation method of the flexible photosensitive developable cover film of the present invention may be on one side of the photosensitive adhesive layer formed in the second step. Fit the release film. In other words, a flexible photosensitive development type cover film in which a base film is laminated on one side of the photosensitive adhesive layer and a release film is laminated on the other side can be prepared through the third step.

On the other hand, the polyimide resin of the present invention can be prepared by the following method.

First, in step (1), a polyamic acid solution can be prepared by mixing a diamine compound, an acid anhydride compound, and a solvent and reacting. In this case, the solvent of step (1) may use an organic solvent, preferably, it may contain selected from methyl ethyl ketone, toluene, N,N-dimethylacetamide, N-methylpyrrolidone, and cyclohexane. One or more of ketones and methylcyclohexanone, more preferably, may contain N-methylpyrrolidone.

Specifically, step (1) can be achieved by putting polyetheramine as a diamine compound, the compound represented by the above chemical formula 1 and the compound represented by the above chemical formula 2 and the solvent at a temperature of 15 to 35° C., preferably, at 20 Mix for 30 to 90 minutes under the temperature condition of ~30°C, preferably for 45 to 75 minutes to prepare the diamine mixture. Then, after adding the compound represented by the above-mentioned chemical formula 4 as an acid anhydride compound to the diamine mixture, it is stirred at a temperature of 15 to 35°C, preferably at a temperature of 20 to 30°C, for 5 to 25 minutes, preferably, Stir for 10 to 20 minutes, then, after adding the compound represented by the above chemical formula 5, it can be stirred at a temperature of 15 to 35°C, preferably at a temperature of 20 to 30°C, for 2 to 6 hours, preferably, stirring 3 to 5 hours and react to prepare a polyamide acid solution.

Next, in step (2), the polyimide solution prepared in step (1) can be subjected to imidization reaction to prepare a polyimide resin with a solid content of 30-50 weight percent. Preferably, it can be prepared with 35~45% by weight of solid polyimide resin.

The imidization reaction of step (2) can be at a temperature of 150~250℃, preferably at a temperature of 180 It is performed for 1 to 5 hours under the temperature condition of ~220°C, preferably for 2 to 4 hours. If the temperature of the imidization reaction is lower than 150°C, it may not be completely imidized. If the temperature of the imidization reaction is lower than 250°C, it may have the problem of difficulty in polymerization caused by solvent evaporation. .

The viscosity of the polyimide resin prepared in step (2) can be 100~600cPs (20°C), preferably, the viscosity of the polyimide resin prepared in step (2) can be 200~400cPs (20°C) , The acid value of the polyimide resin prepared in step (2) may be 100-250 mgKOH/g, preferably, the acid value of the polyimide resin prepared in step (2) may be 150-200 mgKOH/g .

Furthermore, the flexible printed circuit board of the present invention includes the aforementioned flexible photosensitive development type cover film. The flexible printed circuit board is an electronic component developed along with the miniaturization and weight reduction of electronic products, and the flexible printed circuit board including the flexible photosensitive developable cover film of the present invention has excellent physical properties.

The flexible printed circuit board of the present invention is the core part of electronic products, and can be used in mobile phones, cameras, notebook computers, wearable devices, computers and accessories, mobile communication terminals, audio-visual equipment, cameras, printers, digital audio-visual discs (DVD ) At least one of a player, a thin film transistor liquid crystal (TFT LCD) display device, a satellite device, a military device, and a medical device. Preferably, it can be used in at least one of a mobile phone, a camera, a notebook computer, and a wearable device.

Above, the present invention has been described centering on examples. This is only an illustration and does not limit the examples of the present invention. As long as the embodiments of the present invention belong to those of ordinary skill in the art, they can do so within the scope of the sub-characteristics of the present invention. Various modifications and applications not exemplified in the above are implemented. For example, each structural element specifically shown in the example of the present invention may be modified and implemented. In addition, differences related to such deformations and applications are included in the scope of the present invention defined by the scope of protection of the invention.

Preparation Example 1: Preparation of polyimide resin

92.12 g of polyetheramine (Huntsman Co. Jeffamine ED-900), 0.957 g of the compound represented by the following chemical formula 1-1, 7.75 g of the compound represented by the following chemical formula 2-1, and 210 g of N-form The diamine mixture was prepared by mixing the pyrrolidone at 25°C for 60 minutes. After adding 35.31 g of the compound represented by the following chemical formula 4 to the prepared diamine mixture and stirring for 15 minutes, 4.86 g of the compound represented by the following chemical formula 5 was added and stirred for 4 hours, thereby preparing a polyamide acid solution .

Add 30ml of toluene to the prepared polyamide acid solution. After 30 minutes, The temperature was raised to 200°C and stirred for 3 hours to prepare a polyimide resin having a solid content of 40% by weight, a viscosity of 250 cPs (25°C), and an acid value of 180 mgKOH/g. In this case, toluene is used as an azeotropic compound that easily removes the generated water.

，R₁及R₂為甲基。 In the above chemical formula 2-1, A and B are

, R ₁ and R ₂ are methyl groups.

Example 1: Preparation of flexible photosensitive developing cover film

By mixing 1.84 g of the polyimide resin prepared in Preparation Example 1, 8.38 g of polyurethane resin (Samwha paint Co., 0103-C) containing 5 weight percent of methacrylate components, and 0.26 g of hydroxy ketones Photoinitiator (Irgacure, Irg-184D), 1.03g of cresol novolac epoxy (Kukdo Chem. Co., YDCN-7P) as a thermosetting resin, 3.08g of difunctional as the first acrylic oligomer resin Acrylic oligomer resin (MiwonCo., Miramer WS2100), 0.51g of diisocyanate group-containing acrylic oligomer resin (MiwonCo., SC7100NT) as the second acrylic oligomer resin (MiwonCo., SC7100NT), and 4.91g of a solvent Methyl ethyl ketone (methyl ethyl ketone) to prepare photosensitive adhesive resin.

The prepared photosensitive adhesive resin is uniformly coated on one side of the optical polyterephthalic acid (thickness: 36μm) as the base film, and dried in an in-line drying oven at a temperature of 165°C 5 minutes and form a photosensitive adhesive layer.

Subsequently, a release polyterephthalic acid (SKC Co., SG31-36μm) (thickness: 36μm) was laminated as a release film on one side of the photosensitive adhesive layer to prepare an optical layer laminated on one side of the photosensitive adhesive layer. Polyterephthalic acid and a flexible photosensitive developable cover film laminated with release polyterephthalic acid on the other side. At this time, the thickness of the photosensitive adhesive layer after drying was 30 μm.

Examples 2~9: Preparation of flexible photosensitive developing cover film

The flexible photosensitive development type cover film was prepared in the same method as in Example 1. However, as described in Table 1 and Table 2, different contents of polyurethane resin and thermosetting resin were used to prepare soft photosensitive developable cover films.

Example 10: Preparation of flexible photosensitive developing cover film

The flexible photosensitive development type cover film was prepared in the same method as in Example 1. However, instead of the polyurethane resin containing 5 weight percent of the methacrylate component, a flexible photosensitive development type cover film was prepared using a polyurethane resin containing 3 weight percent of the methacrylate component.

Example 11: Preparation of flexible photosensitive and developing cover film

The flexible photosensitive development type cover film was prepared in the same method as in Example 1. However, instead of the polyurethane resin containing 5 weight percent of the methacrylate component, a flexible photosensitive development type cover film was prepared using a polyurethane resin containing 7 weight percent of the methacrylate component.

Example 12: Preparation of flexible photosensitive developing cover film

The flexible photosensitive development type cover film was prepared in the same method as in Example 1. However, instead of the polyurethane resin containing 5 weight percent of the methacrylate component, a flexible photosensitive developable cover film was prepared using a polyurethane resin containing 15 weight percent of the methacrylate component.

Comparative Example 1: Preparation of flexible photosensitive developing cover film

1.84 g of polyimide resin prepared in Preparation Example 1, 8.38 g of polyurethane resin (Samwha paint Co., 0103-C) containing 5 weight percent of methacrylate component, and 0.26 g of hydroxy ketones were mixed Photoinitiator (Irgacure, Irg-184D), 3.08g of difunctional acrylic oligomer resin (MiwonCo., Miramer WS2100) as the first acrylic oligomer resin, 0.51g of the second acrylic oligomer resin Diisocyanate group-containing acrylic oligomer resin (Miwon Co., SC7100NT) and 4.91 g of methyl ethyl ketone as a solvent were used to prepare a photosensitive adhesive resin.

The prepared photosensitive adhesive resin is uniformly coated on one side of the optical polyterephthalic acid (thickness: 36μm) as the base film, and dried in an in-line drying oven at a temperature of 165°C 5 minutes and form a photosensitive adhesive layer.

Subsequently, a release polyterephthalic acid (SKC Co., SG31-36μm) (thickness: 36μm) was laminated as a release film on one side of the photosensitive adhesive layer to prepare an optical layer laminated on one side of the photosensitive adhesive layer. Polyterephthalic acid and a flexible photosensitive developable cover film laminated with release polyterephthalic acid on the other side. At this time, the thickness of the photosensitive adhesive layer after drying was 30 μm.

Experimental example 1

Based on the following physical property evaluation criteria, the flexible photosensitive developable cover films prepared in the foregoing Examples 1 to 12 and Comparative Example 1 were evaluated, and the results are shown in Table 1.

(1)Developability, resolution

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1-12 and Comparative Example 1, and layering on one side of a copper clad laminate (Copper Clad Laminate, CCL) with a circuit pattern formed on one side Press (Roll Lami. 60°C). Subsequently, an exposure mask (Mask) with holes (Hole) of 50μm, 100μm, and 200μm was applied to the optical polyterephthalic acid part of the flexible photosensitive cover film, and the MIDAS system (MDA-400S Aligner) was used. 200mJ/cm ₂ ) Perform exposure treatment. Subsequently, development was carried out in a weakly alkaline developing solution (1 wt% Na ₂ CO ₃ , 35° C., Dipping), and the developing property was evaluated. In addition, after the development, when the circuit pattern is observed with an optical microscope, the resolution is measured by measuring the minimum width (unit: μm) that can completely remove the pitch width between the line widths of the unexposed portions. The smaller the value, the better the evaluation of resolution.

(2) Flexibility (MIT)

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1 to 12 and Comparative Example 1, a MIT L/S=50/50μm circuit was formed on one side The patterned copper clad laminate surface is laminated (Roll Lami. 60°C). Subsequently, the MIDAS system (MDA-400S Aligner 200mJ/cm2) was used for exposure processing. The test piece was prepared by full cure in a curing oven (CURE OVEN) at a temperature of 175°C for 2 hours.

Under the following conditions, the prepared test piece was repeatedly bent using a Massachusetts Institute of Technology (MIT) tester to find the period (= times) during which no conduction was obtained. In one evaluation, five test pieces were tested, and the average value of which conduction was not observed was calculated.

*Massachusetts Institute of Technology test conditions*

Load: 500gf

Angle: 135° opposite

Speed: 175 times/minute

Front end: R0.38mm cylinder

(3) Lead heat resistance

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1 to 12 and Comparative Example 1, lamination was performed on the surface of the copper clad laminate with circuit patterns formed on one side (Roll Lami. 60°C) . Subsequently, an exposure mask with holes of 50 μm, 100 μm, and 200 μm was applied to the optical polyterephthalic acid part of the flexible photosensitive development type cover film, and exposure treatment was performed using a MIDAS system (MDA-400S Aligner 200 mJ/cm ² ). Subsequently, the test piece was prepared by fully curing in a curing oven at a temperature of 175°C for 2 hours.

Under the following conditions, the prepared test piece is humidified and then immersed in molten solder at 260°C to 320°C for 1 minute, and then observed with the naked eye. If there is no abnormality such as foaming or expansion, It is qualified.

Measurement conditions

評價標準：IPC TM-650 2.4.13

Evaluation standard: IPC TM-650 2.4.13

試樣形狀：15mm×30mm

Sample shape: 15mm×30mm

調濕條件：在22.5℃至23.5℃的溫度、39.5%至40.5%的濕度環境下放置24小時。

Humidity conditioning conditions: Place for 24 hours at a temperature of 22.5°C to 23.5°C and a humidity of 39.5% to 40.5%.

(4) Chemical resistance

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1 to 12 and Comparative Example 1, lamination was performed on the surface of the copper clad laminate with circuit patterns formed on one side (Roll Lami. 60°C) . Subsequently, an exposure mask with holes of 50 μm, 100 μm, and 200 μm was applied to the optical polyterephthalic acid part of the flexible photosensitive development type cover film, and exposure treatment was performed using a MIDAS system (MDA-400S Aligner 200 mJ/cm ₂ ). Subsequently, the test piece was prepared by fully curing in a curing oven at a temperature of 175°C for 2 hours.

After immersing the prepared test piece (25℃*30min) in acid solution (10vol% H ₂ SO ₄ ), alkali solution (10% NaOH) and alcohol (IPA), observe whether the appearance changes, and it sticks to the grid After the Cross Cut Test (Elcometer 99 tape, ASTM D 3359), the chemical resistance is measured by confirming whether there is peeling off.

(5) Adhesion

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1 to 12 and Comparative Example 1, lamination was performed on the surface of the copper clad laminate with circuit patterns formed on one side (Roll Lami. 60°C) . Subsequently, the MIDAS system (MDA-400S Aligner 200 mJ/cm ₂ ) was used for exposure processing. Subsequently, the test piece was prepared by fully curing in a curing oven at a temperature of 175°C for 2 hours.

After the adhesion test (Elcometer 99 tape, ASTM D 3359), the chemical resistance is measured by confirming whether there is peeling off.

Plugging

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1-12 and Comparative Example 1, the copper (Copper) with a thickness of 30μm was formed at a pitch of L/S=60~160μm Laminate the copper clad laminate surface with circuit patterns (Roll Lami. 60°C). Subsequently, by using The optical microscope observes the gap between the patterns and whether the circuit is lifted or not to judge the filling characteristics.

(7) Transfer resistance (Migration)

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1-12 and Comparative Example 1, layer the copper-clad board with a circuit pattern formed on one side at L/S=50/50μm Press (Roll Lami. 60°C). Subsequently, the MIDAS system (MDA-400S Aligner 200 mJ/cm ₂ ) was used for exposure processing. Subsequently, the test piece was prepared by fully curing in a curing oven at a temperature of 175°C for 2 hours.

The insulation resistance is measured under the conditions of 85°C/85%RH 50V by welding the circuit pattern and the electric wire for current application. When the insulation resistance characteristic is 1×10 ₉ or more, it is judged that the transfer resistance characteristic is good when kept for 1000 hours.

(8) Bending formability

After removing the release polyterephthalic acid of the flexible photosensitive developable cover film prepared in Examples 1 to 12 and Comparative Example 1, lamination was performed on the surface of the copper clad laminate with circuit patterns formed on one side (Roll Lami. 60°C) . Subsequently, the MIDAS system (MDA-400S Aligner 200 mJ/cm ₂ ) was used for exposure processing. Subsequently, the test piece was prepared by fully curing in a curing oven at a temperature of 175°C for 2 hours.

Using a bending formability measuring device, the number of times that there is no short circuit when the test piece is pressed 180 degrees and released is repeated five times, and the bending formability is judged by the average value.

It can be confirmed from Table 1 above that, among the flexible photosensitive developable cover films prepared in Examples 1 to 5, the developability, resolution, flexibility, and chemical resistance of the flexible photosensitive developable cover film prepared in Example 1 The most excellent physical properties such as performance, adhesion, plugging, transfer resistance, and bending formability.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 2 has reduced flexibility, transfer resistance, and bend moldability.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 3 has poor developability and resolution, significantly reduced flexibility, and reduced adhesion. , The plugging property is improved, and the transfer resistance and bending formability are significantly reduced.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 4 has reduced lead heat resistance, improved plugging properties, and decreased transfer resistance.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 5 has poor developability and resolution, reduced lead heat resistance, and plugging properties. Improved and reduced transfer resistance.

From Table 2 above, it can be confirmed that, compared with the flexible photosensitive developable cover film prepared in Example 1, the flexible photosensitive developable cover film prepared in Example 6 has reduced flexibility, reduced lead heat resistance, and transfer resistance. , Decrease in bending formability.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 7 has significantly reduced flexibility, significantly reduced lead heat resistance, and poor chemical resistance. , The bonding force is reduced, the plugging property is significantly improved, and the transfer resistance and bending formability are significantly reduced.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 8 has poor resolution, reduced flexibility, improved plugging properties, and transfer resistance. Sexual decrease.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 9 has a significantly poorer resolution, reduced flexibility, poor chemical resistance, and adhesion. The force is reduced, the plugging property is significantly improved, and the transfer resistance is significantly reduced.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Comparative Example 1 has significantly reduced flexibility, heat resistance cannot be detected by lead, and chemical resistance. The state of warping, and the bonding strength is also in the state of warping, the plugging property is significantly improved, and the transfer resistance and bending formability are significantly reduced.

It can be confirmed from Table 3 above that, compared with the flexible photosensitive developable cover film prepared in Example 1, the flexible photosensitive developable cover film prepared in Example 10 has poor resolution, reduced flexibility, and reduced lead heat resistance , The plugging property is improved, and the transfer resistance and bending formability are reduced.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 11 has poor resolution, reduced flexibility, reduced lead heat resistance, and transfer resistance. Decrease in flexibility and bending formability.

In addition, compared with the flexible photosensitive developable cover film prepared in Example 1, it can be confirmed that the flexible photosensitive developable cover film prepared in Example 12 has significantly poorer resolution, significantly reduced flexibility, and reduced lead heat resistance. The plugging property is improved, and the transfer resistance and bending formability are significantly reduced.

A person of ordinary skill in the art can easily make simple modifications or changes to the present invention, and these modifications or changes can be regarded as all included in the field of the present invention.

10: Photosensitive adhesive layer

20: Basement membrane

30: Release film

Claims (11)

A flexible photosensitive developing type cover film, which includes a photosensitive adhesive layer, the photosensitive adhesive layer contains a cured product of a photosensitive adhesive resin, the cured product is a cured product of a B-stage state, and the photosensitive adhesive resin contains polyamide An imine resin, a thermosetting resin, and a polyurethane resin. The polyurethane resin is a reactant of a mixture of polycarbonate diol, ring-containing diisocyanate, carboxyl-containing diol compound, and hydroxyl-containing acrylate, and has alkali solubility and Photocurability; wherein, the polyurethane resin is a reactant of a mixture containing the following substances, that is, relative to 100 parts by weight of polycarbonate diol, containing 55 to 103 parts by weight of ring group-containing diisocyanate, 17 to 33 Parts by weight of the carboxyl-containing diol compound and 6-13 parts by weight of the hydroxyl-containing acrylate; and wherein, relative to 100 parts by weight of the polyimide resin, the photosensitive adhesive resin contains 409 to 501 parts by weight of polyurethane Resin and 50~62 parts by weight of thermosetting resin. The flexible photosensitive developable cover film described in the first item of the scope of patent application, wherein the polyurethane resin contains a methacrylate component in an amount of 10% by weight or less. The flexible photosensitive developable cover film described in item 1 of the scope of patent application, wherein the polycarbonate diol has a number average molecular weight (Mn) of 500 to 1100, and the ring group-containing diisocyanate comprises the following chemical formula 6 The compound represented by the carboxyl group-containing diol compound contains the compound represented by the following chemical formula 7, and the hydroxyl group-containing acrylate contains the compound represented by the following chemical formula 8:

In this chemical formula 6, D is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -, R ₆ , R ₇ , R ₈ , R ₉ , R ₁₀ , R ₁₁ , R ₁₂ , R ₁₃ and R ₁₄ are each independently -H or a C1-C5 alkyl group,

In the chemical formula 7, E, F, and G are each independently -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -, R ₁₅ is a C1~C5 alkyl group,

In this chemical formula 8, J is -CH ₂ -, -CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ -, -CH ₂ CH ₂ CH ₂ CH ₂ -or -CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ -. The flexible photosensitive and developable cover film described in item 1 of the scope of patent application, wherein the viscosity of the polyurethane resin is 1100~5000 cPs (25°C). The flexible photosensitive developable cover film described in item 1 of the scope of patent application, wherein the polyimide resin has alkali solubility and non-photocurable properties. According to the first item of the scope of patent application, the flexible photosensitive developable cover film, wherein the photosensitive adhesive resin further contains one or more selected from acrylic oligomer resin, photoinitiator and solvent. According to the first item of the scope of patent application, the flexible photosensitive developing type cover film, wherein the thickness of the photosensitive adhesive layer is 10-40 μm. The flexible photosensitive and developable cover film as described in item 1 of the scope of patent application, wherein the flexible photosensitive and developable cover film further includes: a base film laminated on one side of the photosensitive adhesive layer; and a release film laminated On the other side of the photosensitive adhesive layer. A method for preparing a flexible photosensitive developable cover film, which comprises: a first step of preparing a photosensitive adhesive resin by mixing polyimide resin, polyurethane resin, thermosetting resin, acrylic oligomer resin, photoinitiator and solvent ; And the second step, the photosensitive adhesive resin is coated on one side of the base film, and dried on one side of the base film A photosensitive adhesive layer is formed on the surface, and the polyurethane resin is a reactant comprising a mixture of polycarbonate diol, ring-containing diisocyanate, carboxyl-containing diol compound, and hydroxyl-containing acrylate; wherein, the polyurethane resin contains The reactant of a mixture of the following substances, that is, relative to 100 parts by weight of polycarbonate diol, containing 55 to 103 parts by weight of ring group-containing diisocyanate, 17 to 33 parts by weight of carboxyl group-containing diol compound, and 6 ~13 parts by weight of hydroxyl-containing acrylate; and wherein, relative to 100 parts by weight of polyimide resin, the photosensitive adhesive resin includes 409 to 501 parts by weight of polyurethane resin and 50 to 62 parts by weight of thermosetting resin. A flexible printed circuit board, which includes the flexible photosensitive and developable cover film described in any one of items 1 to 8 of the scope of patent application. The flexible printed circuit board described in item 10 of the scope of patent application, wherein the flexible printed circuit board is used in at least one of mobile phones, cameras, notebook computers and wearable devices.

Images