A photosensitive film laminate, a cured film, a printed wiring board, and an electronic device

Abstract

The application belongs to the technical field of film materials. The application provides a photosensitive film laminated body, which comprises a support layer and a photosensitive layer; the photosensitive layer is arranged on one side of the support layer; the photosensitive layer is subjected to heat treatment, the heat treatment is treatment at 100 DEG C for 15 minutes, the photosensitive layer has a first birefringence n1 before the heat treatment, the photosensitive layer has a second birefringence n2 after the heat treatment, the change rate of the birefringence of the photosensitive layer before and after the heat treatment is Δn = |n2-n1| / n1, and the change rate Δn of the birefringence of the photosensitive layer is 0-15%. The application further provides a cured film. The application further provides an application of the cured film. In the application, the photosensitive layer of the photosensitive film laminated body can still maintain a low haze after heat treatment, and has good heat resistance and aging resistance.

Description

Technical Field

[0001] This application belongs to the field of membrane material technology, and in particular relates to a photosensitive thin film laminate, a cured film, a printed circuit board, and electronic devices. Background Technology

[0002] In the manufacturing process of components such as printed circuit boards, integrated circuits, liquid crystal display panels and touch panels, positive or negative photosensitive resin compositions are usually used to prepare photosensitive layers.

[0003] Utilizing the photosensitive properties of photosensitive layers, they can be designed into specific patterns and ultimately thermo-cured to form protective layers, insulating layers, passivation layers, or solder resist layers. In liquid crystal display panels, touch panels, or printed circuit boards with specific applications, photosensitive layers are also required to have good light transmittance.

[0004] However, in the process of implementing the technical solution of the embodiments of this application, the applicant discovered that the above-mentioned technology has at least the following technical problems:

[0005] With the trend towards miniaturization and high integration, the ambient temperature of photosensitive layers during application is getting higher and higher. Photosensitive layers prepared by existing photosensitive resin compositions have poor heat resistance and aging resistance. The aging process of the photosensitive layer is accelerated after being heated, which affects the transparency of the photosensitive layer. Summary of the Invention

[0006] This application provides a photosensitive film laminate that solves the problem of poor heat resistance of the photosensitive layer in the prior art, which leads to accelerated aging after heating, thereby improving the heat resistance and aging resistance of the photosensitive layer.

[0007] This application provides a photosensitive thin film laminate, which includes a support layer and a photosensitive layer; the photosensitive layer is disposed on one side of the support layer; the extension direction of the photosensitive layer is defined as the x-direction of the photosensitive layer, the transverse direction of the photosensitive layer is defined as the y-direction of the photosensitive layer, and the direction perpendicular to the photosensitive layer is defined as the z-direction of the photosensitive layer; the photosensitive layer has a refractive index n in the x-direction. x The photosensitive layer has a refractive index n in the y direction. y The photosensitive layer has a refractive index n in the z-direction. z The photosensitive layer has a birefringence n, and the birefringence n = (n x -n z ) / (n y -n zThe photosensitive layer is heat-treated at 100°C for 15 minutes. Before the heat treatment, the photosensitive layer has a first birefringence n1, and after the heat treatment, it has a second birefringence n2. The rate of change of the birefringence of the photosensitive layer before and after the heat treatment is Δn = |n2-n1| / n1, and the rate of change of the birefringence Δn of the photosensitive layer is 0 to 15%.

[0008] Furthermore, before heat treatment, the photosensitive layer has a first haze H1, and after heat treatment, the photosensitive layer has a second haze H2. The rate of change of haze of the photosensitive layer before and after heat treatment is ΔH=|H2-H1| / H1, and the rate of change of haze of the photosensitive layer ΔH is 0~10%.

[0009] Furthermore, the first birefringence n1 of the photosensitive layer is less than or equal to 2, and the transmittance of the photosensitive layer in the wavelength range of 400 to 760 nm is greater than or equal to 80%.

[0010] Furthermore, the photosensitive layer includes a photosensitive resin composition comprising a first alkali-soluble resin, a first diluent monomer, a first photoinitiator, and a first thermosetting agent.

[0011] Furthermore, the first alkali-soluble resin includes aliphatic segments, and the weight percentage of the aliphatic segments in the first alkali-soluble resin is greater than or equal to 30%.

[0012] Furthermore, the first dilution monomer is an aliphatic compound.

[0013] Furthermore, the photosensitive resin composition also includes inorganic fillers, the weight percentage of which is less than or equal to 8%.

[0014] Furthermore, the photosensitive film laminate also includes a reflective layer, which is disposed between the support layer and the photosensitive layer; the reflective layer has a reflectivity of greater than or equal to 80% in the wavelength range of 400 to 760 nm.

[0015] Furthermore, the sum of the thickness of the reflective layer and the thickness of the photosensitive layer is 25–60 μm, with the thickness of the reflective layer being greater than that of the photosensitive layer.

[0016] Furthermore, the thickness of the photosensitive layer is 5–10 μm, and the thickness of the reflective layer is 10–45 μm.

[0017] Furthermore, the reflective layer comprises a reflective resin composition, which includes a second alkali-soluble resin, a second diluent monomer, a second photoinitiator, a second thermosetting agent, and a white pigment.

[0018] Furthermore, the white pigment includes at least one of titanium dioxide or barium sulfate.

[0019] This application provides a cured film, which is formed by removing the support layer from any of the above-mentioned photosensitive film laminates and then curing it by at least one of photocuring or thermal curing methods.

[0020] This application provides a printed circuit board that includes the aforementioned cured film.

[0021] This application provides an electronic device that includes the above-described cured film or the above-described printed circuit board.

[0022] In this application, the birefringence of the photosensitive layer of the photosensitive film laminate does not change much before and after heat treatment, and the light transmittance of the photosensitive layer does not change much before and after heat treatment. This ensures that the photosensitive layer can maintain good transparency even when used for a long time in a high-temperature environment, thereby improving the heat resistance, aging resistance and light transmittance of the photosensitive layer. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of a photosensitive thin film laminate in one embodiment of this application;

[0024] Figure 2 This is a schematic cross-sectional view of a photosensitive thin film laminate in one embodiment of this application;

[0025] Figure 3 This is a cross-sectional structural diagram of a photosensitive thin film laminate in another embodiment of this application;

[0026] Figure 4 This is a cross-sectional structural diagram of a photosensitive thin film laminate in another embodiment of this application;

[0027] Figure 5 This is a cross-sectional structural diagram of a photosensitive thin film laminate in another embodiment of this application;

[0028] Figure 6 This is a cross-sectional structural diagram of the cured film in one embodiment of this application.

[0029] In the figure: photosensitive film laminate 100, support layer 11, photosensitive layer 12, protective layer 13, reflective layer 14; curing film 200. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present invention, the technical solutions in specific embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0031] This application provides a method such as Figure 1The photosensitive film laminate 100 shown includes a support layer 11 and a photosensitive layer 12, with the photosensitive layer 12 disposed on one side of the support layer 11. The support layer 11 serves as the substrate for the photosensitive layer 12. The extending direction of the photosensitive layer 12 is defined as the x-direction, the transverse direction as the y-direction, and the direction perpendicular to the photosensitive layer 12 as the z-direction. In the x-direction, the photosensitive layer 12 has a refractive index n. x The photosensitive layer 12 has a refractive index n in the y direction. y The photosensitive layer 12 has a refractive index n in the z-direction. z The photosensitive layer 12 has a birefringence n, and the birefringence n = (n x -n z ) / (n y -n z The photosensitive layer 12 is heat-treated at 100°C for 15 minutes. Before heat treatment, the photosensitive layer 12 has a first birefringence n1, and after heat treatment, it has a second birefringence n2. The rate of change of the birefringence of the photosensitive layer 12 before and after heat treatment is Δn = |n2 - n1| / n1, and the rate of change Δn is 0–15%. The small rate of change Δn of the birefringence of the photosensitive layer 12 before and after heat treatment ensures that the light transmittance of the photosensitive layer 12 does not change significantly. This also ensures that the photosensitive layer 12 has good heat resistance.

[0032] As an optional implementation, before heat treatment, the photosensitive layer 12 has a first haze H1, and after heat treatment, the photosensitive layer 12 has a second haze H2. The first haze H1 is less than or equal to 8%, preferably less than or equal to 5%, and more preferably less than or equal to 3%. Haze is an important indicator characterizing the light transmittance of a material; the lower the haze, the better the light transmittance. A smaller first haze H1 ensures that the turbidity of the photosensitive layer 12 is low, giving the photosensitive film high clarity and good light transmittance before heat treatment. The rate of change of haze of the photosensitive layer 12 before and after heat treatment is ΔH = |H2 - H1| / H1, and the rate of change of haze ΔH of the photosensitive layer 12 is 0 to 10%. A lower rate of change of haze ΔH of the photosensitive layer 12 ensures that the photosensitive layer 12 can still maintain good light transmittance when used for a long time in a high-temperature environment.

[0033] As an optional implementation, the first birefringence n1 of the photosensitive layer 12 is less than or equal to 2, and the transmittance of the photosensitive layer 12 in the wavelength range of 400–760 nm is greater than or equal to 80%. A higher birefringence makes it easier for images to produce distortions. Having a first birefringence n1 less than or equal to 2 ensures that the photosensitive layer 12 has high light transmission quality. A transmittance of greater than or equal to 80% in the wavelength range of 400–760 nm ensures that the photosensitive layer 12 has good light transmission performance.

[0034] As an optional implementation method, such as Figure 2 As shown, the thickness of the photosensitive layer 12 is 5–45 μm, ensuring that the photosensitive layer 12 has both sufficient strength and good light transmittance. The thickness of the support layer 11 is 10–40 μm, ensuring that the support layer 11 can provide good support.

[0035] As an optional implementation, the support layer 11 includes at least one of PET film, PP film, PE film, PEN film, PVDF film, PEO film, PSS film, polyvinyl acetate saponified film, or ethylene oxide copolymer film. These films have good mechanical properties, high impact strength, good folding resistance, and good light transmittance, ensuring that the support layer 11 can provide good support without affecting the effect of subsequent exposure processing. PET film, PP film, PE film, PEN film, PVDF film, PEO film, PSS film, polyvinyl acetate saponified film, and ethylene oxide copolymer film have high corrosion resistance and low cost, which can improve the reliability of the support layer 11 and reduce the manufacturing cost of the photosensitive film laminate 100.

[0036] As an optional embodiment, the photosensitive layer 12 includes a photosensitive resin composition. The photosensitive resin composition imparts photosensitive properties to the photosensitive layer 12. Utilizing the photosensitive properties of the photosensitive layer 12, it can be designed into specific patterns. The photosensitive resin composition includes a first alkali-soluble resin, a first diluent monomer, a first photoinitiator, and a first thermosetting agent, ensuring that the photosensitive layer 12 prepared from the photosensitive resin composition has good light transmittance.

[0037] As an optional implementation, the first alkali-soluble resin comprises aliphatic resin segments (aliphatic chains and alicyclic rings), and the weight percentage of the aliphatic segments in the first alkali-soluble resin is greater than or equal to 30%. Preferably, the first alkali-soluble resin is a non-aromatic resin. The first diluting monomer is an aliphatic compound. The photosensitive resin composition also includes inorganic fillers, and the weight percentage of the inorganic fillers in the photosensitive resin composition is less than or equal to 8%, ensuring that the photosensitive layer 12 has good light transmittance and curing effect.

[0038] As an optional embodiment, the first alkali-soluble resin comprises an acrylic resin and / or an alkali-soluble polyimide resin; the monomer unit of the acrylic resin is selected from itaconic acid, crotonic acid, acrylic acid, methacrylic acid, maleic acid half ester, maleic acid, fumaric acid, vinyl acetic acid and its anhydrides, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, isooctyl methacrylate, lauryl methacrylate, octadecyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate. The first alkali-soluble resin comprises any one or more of the following: polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, (meth)acrylonitrile, (meth)acrylate glycidyl acrylate, N,N-dimethyl(meth)acrylate ethyl acrylate, N,N-diethyl(meth)acrylate ethyl acrylate, N,N-dimethyl(meth)acrylate propyl acrylate, N,N-diethyl(meth)acrylate propyl acrylate, N,N-dimethyl(meth)acrylate butyl acrylate, N,N-diethyl(meth)acrylate butyl acrylate, (meth)acrylamide, N-hydroxymethylacrylamide, N-butoxymethylacrylamide, styrene, (meth)acrylate benzyl acrylate, phenoxyethyl (meth)acrylate, or (alkoxylated)nonylphenol (meth)acrylate. The acid value of the first alkali-soluble resin is 10–150 mg KOH / g, and the weight-average molecular weight of the first alkali-soluble resin is 2000–150000.

[0039] As an optional implementation, the first diluting monomer is a monomer containing an olefinically unsaturated group, and can also be selected from conventional photopolymerizable monomers, including but not limited to monofunctional (meth)acrylates, difunctional (meth)acrylates, trifunctional (meth)acrylates, or polyfunctional (meth)acrylates, specifically such as (ethoxy)phenol (meth)acrylate, stearate acrylate, ethoxy(propoxy)nonylphenol (meth)acrylate, ethoxy(propoxy)tetrahydrofurfuryl (meth)acrylate, 1, 6-Hexanediol diacrylate, tricyclodecanediethanol diacrylate, dioxanediol diacrylate, ethoxylated (propoxylated)bisphenol A di(meth)acrylate, polyethylene glycol (400) diacrylate, polypropylene glycol (600) diacrylate, ethoxylated (propoxylated)trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate, tri(2-hydroxyethyl)isocyanurate triacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate, or dipentaerythritol hexaacrylate.

[0040] As an optional implementation, the first photoinitiator is selected from conventional photopolymerization initiators and photosensitizers, such as diacene-based, acetophenone-based, oxime-based, phosphine oxide-based, anthrone-based, benzoyl ether, benzophenone-based, anthraquinone-based, thioxanthone compounds, hexaaryl diimidazole compounds, or acridine compounds, specifically including 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 2-(acetoxyiminomethyl)thioxan-9-one, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]acetophenone-1-(O-acetyloxime), 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1- One or more of the following: acetone, 1-[4-(2-hydroxy)-phenyl]-3-hydroxy-2-methyl-1-propanone-1-one, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, diethyl 2,4-oxalate, 2,4-diethylthiazolinone, 2-isopropylthioxanthone, 2-ethylanthraquinone, 2,4-diethylthioxanthone, or benzophenone.

[0041] As an optional implementation, the first thermosetting agent includes one or more of epoxy resin, isocyanate or isocyanurate compounds or triazine compounds; the epoxy resin includes one or more of bisphenol type epoxy resin, biphenyl type epoxy resin, phenolic epoxy resin, epoxy resin containing a naphthalene ring, and alicyclic epoxy resin; the bisphenol type epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; the phenolic epoxy resin includes one or more of phenolic phenolic type epoxy resin or phenolic type epoxy resin. The epoxy equivalent of the epoxy resin is 50-350 g / eq, and the softening point is 40-150℃.

[0042] As an alternative implementation, the inorganic filler includes at least one of silica, talc, barium sulfate, calcium carbonate, or zinc oxide.

[0043] As an optional implementation, the photosensitive resin composition comprises, by weight parts, 100 parts of a first alkali-soluble resin, 10 to 50 parts of a first diluent monomer, 0.5 to 10 parts of a first photoinitiator, 5 to 50 parts of a first thermosetting agent, and 0 to 5 parts of an inorganic filler.

[0044] As an optional implementation method, such as Figure 3As shown, the photosensitive film laminate 100 further includes a protective layer 13, which is disposed on the side of the photosensitive layer 12 away from the support layer 11. The protective layer 13 protects the photosensitive layer 12 and prevents it from being damaged. The thickness of the protective layer 13 is 10–40 μm, ensuring that it provides good protection while having minimal impact on the overall light transmittance.

[0045] As an optional implementation, the protective layer 13 includes at least one of a PET film, PP film, PE film, PEN film, PVDF film, PEO film, PSS film, polyvinyl acetate saponified film, or ethylene oxide copolymer film. These films have good mechanical properties, high impact strength, and good folding resistance, ensuring that the protective layer 13 can provide good support. PET films, PP films, PE films, PEN films, PVDF films, PEO films, PSS films, polyvinyl acetate saponified films, and ethylene oxide copolymer films have high corrosion resistance and are inexpensive, which can improve the reliability of the protective layer 13 and reduce the manufacturing cost of the photosensitive film laminate 100.

[0046] As an optional implementation method, such as Figure 4 As shown, the photosensitive thin film laminate 100 also includes a reflective layer 14, which is disposed between the support layer 11 and the photosensitive layer 12. The reflective layer 14 enables the photosensitive thin film laminate 100 to have high reflectivity, which can improve light utilization, brightness, and contrast when applied in display devices. Combining the reflective layer 14 with the photosensitive layer 12 can also solve the problems of deep curing, side etching, and yellowing caused by excessive reflectivity in conventional single-layer photosensitive films, while still achieving the same high reflectivity as conventional photosensitive films. The reflective layer 14 has a reflectivity of greater than or equal to 80% in the wavelength range of 400–760 nm, and the sum of the thickness of the reflective layer 14 and the thickness of the photosensitive layer 12 is 25–60 μm, with the thickness of the reflective layer 14 being greater than the thickness of the photosensitive layer 12. To ensure the structure of the reflective layer 14 and photosensitive layer 12 is relatively thin yet possesses sufficient strength, and to guarantee that the reflectivity remains unaffected while maintaining a certain pigment content per unit volume, if the reflective layer 14 is too thin, the pigment content per unit volume of the reflective layer 14 needs to be significantly increased. However, excessive pigment content will affect the flexibility, resolution, and adhesion between this layer and other layers. Specifically, a white reflective layer can be selected to further ensure its reflectivity.

[0047] As an optional implementation, when the photosensitive film laminate 100 is provided with a reflective layer 14, the thickness of the photosensitive layer is preferably 5 to 10 μm, and the thickness of the reflective layer is preferably 10 to 45 μm, so as to ensure that the photosensitive film laminate 100 has good deep curing properties.

[0048] As an optional implementation method, such as Figure 5As shown, the protective layer 13 and the reflective layer 14 can be provided simultaneously in the photosensitive film laminate 100.

[0049] As an alternative implementation, the reflective layer 14 is formed by curing a reflective resin composition comprising a second alkali-soluble resin, a second diluent monomer, a second photoinitiator, a second thermosetting resin, and a white pigment.

[0050] As an optional embodiment, the second alkali-soluble resin comprises an acrylic resin and / or an alkali-soluble polyimide resin; the monomer unit of the acrylic resin is selected from itaconic acid, crotonic acid, acrylic acid, methacrylic acid, maleic acid half ester, maleic acid, fumaric acid, vinylacetic acid and its anhydrides, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, isooctyl methacrylate, lauryl methacrylate, octadecyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 4-hydroxybutyl methacrylate. The resin comprises any one or more of the following: polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, (meth)acrylonitrile, (meth)acrylate glycidyl acrylate, N,N-dimethyl(meth)acrylate ethyl acrylate, N,N-diethyl(meth)acrylate ethyl acrylate, N,N-dimethyl(meth)acrylate propyl acrylate, N,N-diethyl(meth)acrylate propyl acrylate, N,N-dimethyl(meth)acrylate butyl acrylate, N,N-diethyl(meth)acrylate butyl acrylate, (meth)acrylamide, N-hydroxymethylacrylamide, N-butoxymethylacrylamide, styrene, (meth)acrylate benzyl acrylate, phenoxyethyl (meth)acrylate, or (alkoxylated)nonylphenol (meth)acrylate. The acid value of the alkali-soluble resin is 10–200 mg KOH / g, and the weight-average molecular weight of the alkali-soluble resin is 2000–150000.

[0051] As an optional implementation, the second diluent monomer is a monomer containing an olefinically unsaturated group, and can also be selected from conventional photopolymerizable monomers, including but not limited to monofunctional (meth)acrylates, difunctional (meth)acrylates, trifunctional (meth)acrylates, or polyfunctional (meth)acrylates, specifically such as (ethoxy)phenol (meth)acrylate, stearate acrylate, ethoxy(propoxy)nonylphenol (meth)acrylate, ethoxy(propoxy)tetrahydrofurfuryl (meth)acrylate, 1, 6-Hexanediol diacrylate, tricyclodecanediethanol diacrylate, dioxanediol diacrylate, ethoxylated (propoxylated)bisphenol A di(meth)acrylate, polyethylene glycol (400) diacrylate, polypropylene glycol (600) diacrylate, ethoxylated (propoxylated)trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate, tri(2-hydroxyethyl)isocyanurate triacrylate, dipentaerythritol hexaacrylate, ethoxylated pentaerythritol tetraacrylate, or dipentaerythritol hexaacrylate.

[0052] As an optional implementation, the second photoinitiator is selected from conventional photopolymerization initiators and photosensitizers, such as diacene-based, acetophenone-based, oxime-based, phosphine oxide-based, anthrone-based, benzoyl ether, benzophenone-based, anthraquinone-based, thioxanthone compounds, hexaaryl diimidazole compounds, or acridine compounds, specifically including 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone, 2-(acetoxyiminomethyl)thioxanth-9-one, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]acetone-1-(O-acetyloxime), 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1- One or more of the following: acetone, 1-[4-(2-hydroxy)-phenyl]-3-hydroxy-2-methyl-1-propanone-1-one, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, diethyl 2,4-oxalate, 2,4-diethylthiazolinone, 2-isopropylthioxanthone, 2-ethylanthraquinone, 2,4-diethylthioxanthone, or benzophenone.

[0053] As an optional implementation, the second thermosetting agent includes one or more of epoxy resin, isocyanate or isocyanurate compounds or triazine compounds; the epoxy resin includes one or more of bisphenol type epoxy resin, biphenyl type epoxy resin, phenolic epoxy resin, naphthalene-containing epoxy resin, and alicyclic epoxy resin; the bisphenol type epoxy resin includes one or more of bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; the phenolic epoxy resin includes one or more of phenolic phenolic type epoxy resin or phenolic type epoxy resin. The epoxy equivalent of the epoxy resin is 50-350 g / eq, and the softening point is 40-150℃.

[0054] As an alternative implementation, the white pigment includes at least one of titanium dioxide or barium sulfate. Titanium dioxide has good weather resistance, is not prone to yellowing, and has strong coloring ability. Sulfuric acid has excellent weather resistance and ultraviolet blocking properties, and high gloss. Both titanium dioxide and barium sulfate can give the reflective layer 14 a high light reflectivity.

[0055] As an optional implementation, rutile titanium dioxide is selected. Rutile titanium dioxide has smaller internal single crystals and a more compact arrangement. Therefore, rutile titanium dioxide has better thermal stability and weather resistance, making the reflective layer 14 less prone to yellowing and improving the reliability of the reflective layer 14.

[0056] As an optional embodiment, the reflective resin composition comprises, by weight parts, 100 parts of a second alkali-soluble resin, 1 to 40 parts of a second diluent monomer, 1 to 5 parts of a second photoinitiator, 1 to 40 parts of a second thermosetting agent, and 50 to 100 parts of a white pigment.

[0057] This application also provides a method such as Figure 6 The cured film 200 shown is formed by curing the photosensitive film laminate 100 after removing the support layer 11, followed by at least one curing method, namely photocuring or thermal curing. Preferably, the cured film 200 is formed by removing the support layer 11 from the photosensitive film laminate 100 and then undergoing both photocuring and thermal curing. Photocuring can utilize the photosensitive properties of the photosensitive layer 12, allowing the photosensitive layer 12 to be designed into a specific pattern. Thermal curing can further cure the encapsulation material, thus completing the entire curing process.

[0058] This application also provides a printed circuit board, which includes the aforementioned cured film 200. The cured film 200 has good light transmittance, low haze, high transparency, and low birefringence, and can still maintain good light transmittance even when used for a long time in a high-temperature environment.

[0059] This application also provides an electronic device, which includes the aforementioned cured film 200 or the aforementioned printed circuit board. The electronic device includes touch panels, mobile phones, computers, and displays, etc.

[0060] The present application will be further described below with reference to the embodiments, but the scope of protection of the present application is not limited to the embodiments.

[0061] Set up the examples and comparative examples according to Tables 1-1 and 1-2.

[0062] Table 1-1: Examples 1-7

[0063]

[0064]

[0065] Table 1-2: Examples 8-12 and Comparative Examples 1-2

[0066]

[0067]

[0068] illustrate:

[0069] A1: Japan Chemicals ZFR-1401H, Bisphenol F type, solid content 60%, acid value 98mgKOH / g;

[0070] A2: Daicel CYCLOMER P(ACA)Z250, alicyclic compound, 45% solids, acid value 70mgKOH / g;

[0071] B1: Sartoma SR350 NS, trimethylolpropane trimethacrylate;

[0072] B2: BASF Laromer LR8863, ethoxylated trimethylolpropane triacrylate;

[0073] C1: Ciba Irgacure 184;

[0074] C2: BASF Irgacare OXE-01;

[0075] D1: Mitsubishi Chemical JER828, epoxy equivalent 189g / eq;

[0076] E1: Silica (Changtai Micro-Nano CT-103);

[0077] a1: Nippon Kayaku ZFR-1401H, bisphenol F type, solid content 60%, acid value 98mgKOH / g;

[0078] b1: Sartoma SR350 NS, trimethylolpropane trimethacrylate;

[0079] c1: IGM Omnirad TPO

[0080] d1: Mitsubishi Chemical JER828, epoxy equivalent 189 g / eq;

[0081] e1: Rutile titanium dioxide (Cholmos R902+);

[0082] e2: Barium sulfate (Sakai Chemical BARIACE B-30).

[0083] Structure: such as Figure 2 As shown, in Examples 1-2, 5, 10-12, and Comparative Example 1, the photosensitive layer is disposed on one side of the support layer. Figure 3 As shown in Examples 3-4 and Example 7, the photosensitive layer is disposed on one side of the support layer, and the protective layer is disposed on the side of the photosensitive layer away from the support layer. Figure 4 As shown, in Examples 6 and 8-9, the photosensitive layer is disposed on one side of the support layer, and the reflective layer is disposed between the photosensitive layer and the support layer. Figure 5 As shown, in Example 7, the photosensitive layer is disposed on one side of the support layer, the protective layer is disposed on the side of the photosensitive layer away from the support layer, and the reflective layer is disposed between the photosensitive layer and the support layer. In Comparative Example 2, the reflective layer is disposed on one side of the support layer.

[0084] Birefringence: such as Figure 1 As shown, in Examples 1-12 and Comparative Examples 1-2, the extension direction of the photosensitive layer is defined as the x-direction of the photosensitive layer, the transverse direction of the photosensitive layer is defined as the y-direction of the photosensitive layer, and the direction perpendicular to the photosensitive layer is defined as the z-direction of the photosensitive layer. In the x-direction, the photosensitive layer has a refractive index n. x The photosensitive layer has a refractive index n in the y direction. y The photosensitive layer has a refractive index n in the z-direction. z All the above refractive index values ​​were measured using an Abbe refractometer. The photosensitive layer has a birefringence n, where birefringence n = (n... x -n z ) / (n y -n z The photosensitive layer is heat-treated at 150°C for 60 minutes. Before the heat treatment, the photosensitive layer has a first birefringence n1, and after the heat treatment, it has a second birefringence n2. The rate of change of the birefringence of the photosensitive layer before and after the heat treatment is Δn=|n2-n1| / n1.

[0085] I. Performance Testing:

[0086] The performance of the photosensitive film laminates in the above embodiments and comparative examples was tested.

[0087] 1. Transmittance test: Using a spectrophotometer (Color Spectrum CS-700), under the conditions of 6500K color temperature and 10° viewing window, 5 points were randomly selected on the surface of the test sample, and the transmittance at each point was measured. The average value of the results was taken.

[0088] 2. Haze test: The test method refers to standard GB / T 2410-2008, and the haze of the film in the visible light band is determined by ultraviolet-visible spectrophotometer.

[0089] 3. Birefringence test: The refractive index of each axis was tested and the birefringence was calculated using the Japanese ATAGO NAR-3T Abbe refractometer.

[0090] 4. Heat aging resistance: at 1000mJ / cm 2 Samples that underwent photocuring under energy and thermocuring at 150℃ for 60 min were placed in an 85℃ / 85%RH constant temperature and humidity chamber for 1000 h. The transmittance value after aging was tested and compared with the transmittance value before aging.

[0091] 5. Resolution Test: A photosensitive layer is laminated onto a copper-clad laminate using heated rollers. Here, a mask with a wiring pattern having a 1:1 (10–100 μm) width ratio between exposed and unexposed areas is exposed. After development for 1.5 times the development removal time, the pattern is observed using a magnifying glass. Resolution is evaluated by the minimum line width that completely removes the unexposed areas without distortion, defects, or remaining lines. The smaller this value, the better the resolution.

[0092] 6. Deep curing performance evaluation: The test method refers to standard GB / T9286-98, using the cross-cut adhesion test. Adhesion is evaluated by observing whether there is any peeling (reflecting the quality of deep curing performance).

[0093] II. Performance Test Results:

[0094] The performance test results of the encapsulating films in the above embodiments and comparative examples are shown in Table 2-1.

[0095] Table 2-1: Test Results

[0096]

[0097] As shown in the table, the photosensitive layers in Examples 1-5 and 10-12 exhibit high transmittance after heat treatment and minimal change in transmittance after heat aging treatment, demonstrating excellent heat resistance and aging resistance. Comparing Examples 1-5 and 10-12 with Comparative Example 1, it is evident that the examples achieve the high transmittance and low resolution of the conventional photosensitive layer in Comparative Example 1, while also exhibiting better heat resistance and aging resistance, ensuring that the photosensitive layer maintains good transparency even after prolonged use in high-temperature environments. Comparing Examples 6-9 with Comparative Example 2, it is clear that the combined use of the reflective layer and the photosensitive layer can improve the deep curing problem of single-layer reflective layers.

[0098] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A photosensitive thin film laminate, characterized in that, include: Support layer; A photosensitive layer is disposed on one side of the support layer; With the extension direction of the photosensitive layer defined as the x-direction, the lateral direction of the photosensitive layer defined as the y-direction, and the direction perpendicular to the photosensitive layer defined as the z-direction, the photosensitive layer has a refractive index n in the x-direction. x The photosensitive layer in the y-direction has a refractive index n y The photosensitive layer in the z-direction has a refractive index n z The photosensitive layer has a birefringence n, and the birefringence n = (n x -n z ) / (n y -n z ); The photosensitive layer is subjected to heat treatment at 100°C for 15 minutes. Before the heat treatment, the photosensitive layer has a first birefringence n1, and after the heat treatment, the photosensitive layer has a second birefringence n2. The rate of change of the birefringence of the photosensitive layer before and after the heat treatment is Δn = |n2 - n1| / n1, and the rate of change of the birefringence Δn of the photosensitive layer is 0 to 15%.

2. The photosensitive thin film laminate according to claim 1, characterized in that: Before the heat treatment, the photosensitive layer has a first haze H1, and after the heat treatment, the photosensitive layer has a second haze H2. The rate of change of the haze of the photosensitive layer before and after the heat treatment is ΔH = |H2-H1| / H1, and the rate of change of the haze of the photosensitive layer is 0 to 10%.

3. The photosensitive thin film laminate according to claim 1, characterized in that: The first birefringence n1 of the photosensitive layer is less than or equal to 2, and the transmittance of the photosensitive layer in the wavelength range of 400 to 760 nm is greater than or equal to 80%.

4. The photosensitive thin film laminate according to claim 1, characterized in that: The photosensitive layer includes a photosensitive resin composition, which includes a first alkali-soluble resin, a first diluent monomer, a first photoinitiator, and a first thermosetting agent. Preferably, the first alkali-soluble resin includes aliphatic segments, and the weight percentage of the aliphatic segments in the first alkali-soluble resin is greater than or equal to 30%. Preferably, the first diluting monomer is an aliphatic compound; Preferably, the photosensitive resin composition further includes an inorganic filler, wherein the inorganic filler has a weight percentage of less than or equal to 8%.

5. The photosensitive thin film laminate according to claim 1, characterized in that: The photosensitive thin film laminate further includes a reflective layer disposed between the support layer and the photosensitive layer; the reflective layer has a reflectivity of greater than or equal to 80% in the wavelength range of 400–760 nm.

6. The photosensitive thin film laminate according to claim 5, characterized in that: The sum of the thickness of the reflective layer and the thickness of the photosensitive layer is 25–60 μm, and the thickness of the reflective layer is greater than the thickness of the photosensitive layer; Preferably, the thickness of the photosensitive layer is 5–10 μm, and the thickness of the reflective layer is 10–45 μm.

7. The photosensitive thin film laminate according to claim 5, characterized in that: The reflective layer comprises a reflective resin composition, which includes a second alkali-soluble resin, a second diluent monomer, a second photoinitiator, a second thermosetting agent, and a white pigment; Preferably, the white pigment includes at least one of titanium dioxide or barium sulfate.

8. A cured film, characterized in that: The cured film is formed by removing the support layer from the photosensitive film laminate as described in any one of claims 1 to 7 and then curing it by at least one curing method, namely photocuring or thermal curing.

9. A printed circuit board, characterized in that: The printed circuit board includes the cured film as described in claim 8.

10. An electronic device, characterized in that: The electronic device includes the cured film as described in claim 8 or the printed circuit board as described in claim 9.

Images