Photocurable resin composition, application thereof, and photosensitive dry film resist laminate

Abstract

The application provides a photocuring resin composition, application thereof and a photosensitive dry film resist laminated body. The photocuring resin composition comprises an alkali-soluble resin, a photopolymerization monomer, a photosensitizer and an additive; the alkali-soluble resin comprises compounds represented by general formula (I) and general formula (II). The compounds represented by general formula (I) and general formula (II) are used in combination to exert their synergistic effect, the performance of the photocuring resin composition is improved by optimizing the molecular structure and introducing the specific functional groups, the photocuring resin composition is suitable for a wet film pasting process and a soft plate roll-to-roll continuous production process, and the production requirements of a precision circuit flexible plate and a rigid plate are met, product yield is improved, and production cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photocuring resin, in particular to a photocuring resin composition, application thereof and a photosensitive dry film resist laminated body. BACKGROUND

[0002] In printed circuit boards, lead frames, solar cells, conductor packages, BGA (Ball Grid Array), CPS (Chip Size Package) packages, photosensitive dry film resists are widely used as key materials for pattern transfer. For example, in the manufacture of printed circuit boards, first, a photosensitive dry film resist laminated on a copper-clad laminate, a flexible substrate or the like is subjected to pattern exposure. The exposed portion of the photosensitive dry film resist is polymerized and cured. Next, the unexposed portion is removed with a developer to form a resist pattern on the substrate. Further, after a conductor pattern is formed by etching or plating treatment, the resist pattern is peeled off and removed from the substrate. By going through these processes, a conductor pattern is formed on the substrate.

[0003] In the manufacture of printed circuit boards using photolithography, depending on the wiring and product characteristics of the end product, substrates having various shapes, such as flat, concave-convex, non-flat, rigid substrates with large through-holes (6 mm round holes or irregularly shaped holes), and flexible substrates with densely packed small-diameter through-holes (100 to 200 μm), are used.

[0004] In recent years, as electronic products have become increasingly thin, light and small, the wiring precision of printed circuit boards and the precision of the connection of electronic components to each other have become increasingly high. Flexible circuit boards (referred to as soft boards or FPCs) have the advantages of high wiring density, light weight, thin thickness, less restriction on wiring space, high flexibility, and fully meet the development trend of thin, light and small electronic products, and can meet the needs of miniaturization and mobility of electronic products, and are widely used in the fields of PC and peripheral products, automotive electronics, medical devices, communication products and consumer electronics, etc.

[0005] The flexible substrate for making flexible circuit board usually includes dense small aperture through holes, especially the flexible circuit board with fine lines, the number of through holes for connecting between wiring layers increases, and the aperture is further reduced to about 100 μm. On the other hand, the copper layer on the flexible substrate is thin, the copper layer surface roughness is low, and it also contains an oxygen resistant layer, and generally no polishing and other pretreatment operation process is performed before lamination with dry film resist. Therefore, in order to improve the adhesion of the photosensitive dry film resist on the flexible substrate, and further improve the product yield, the wet film lamination method is usually used to make the flexible circuit board. The so-called wet film lamination is that a layer of water film is coated on the surface of the copper foil of the substrate before lamination. When the substrate passes through the hot press roller, part of the water is evaporated and removed, and the remaining water is absorbed by the photosensitive dry film resist. Therefore, the originally irregular or recessed surface forms a vacuum, and the water-soluble characteristics of the dry film make the film surface part present in a liquid form, thereby improving the flowability during lamination under pressure, so that the dry film and the copper surface can be firmly matched and adhered. In addition, a small amount of water can significantly improve the adhesion between the photosensitive dry film and PET, prevent the photosensitive dry film from being accidentally broken off due to collision and other factors after exposure, and prevent abnormal situations from occurring.

[0006] The photosensitive dry film resist for making flexible circuit board needs to have good flexibility. After wet film lamination, the dry film resist with good flexibility is easy to penetrate into the small holes of the flexible substrate. For the wet pressing process of the photosensitive dry film for flexible substrate, the inventors found the following actual situations and technical problems in the experiment: after the resist is stripped, sometimes the solidified resist in the small holes is not completely stripped, but remains in part of the small diameter through holes, especially for the flexible circuit board with fine lines, the line size is small and the through hole size is small, so the resolution and adhesion performance of the photosensitive dry film resist are required to be higher. However, when the adhesion performance of the photosensitive dry film resist is excellent, the difficulty of removing the film is large (i.e. difficult to strip), and it is especially difficult to completely remove the solidified resist penetrated into the small holes without residue. When the small through holes of the flexible substrate cannot be completely removed clean (plug hole phenomenon), it will seriously affect the manufacturing yield of the flexible circuit board at the customer end, and even cause the electrical performance of the prepared flexible circuit board to be unqualified and invalid.

[0007] At present, researchers have found that by introducing (meth) acrylic long-chain alkyl ester or a certain amount of propylene oxide block copolymer containing photopolymerization monomer as disclosed in the prior art (publication number CN108490737A) into the alkali-soluble resin of the dry film resist, the film removal speed can be significantly improved, and the problem of incomplete removal of the film in the small holes of the flexible substrate (plug hole) can be improved. However, the experimental results show that: after introducing (meth) acrylic long-chain alkyl ester, the adhesion performance of the dry film resist on the substrate is significantly decreased, which is not conducive to the production of fine lines, and the film removal fragments are obviously large.

[0008] And today's flexible circuit board development trend is its line more and more fine, and there are quite a number of precision circuit flexible circuit board manufacturers, in order to improve production efficiency and yield, using soft plate roll to roll continuous production process. This kind of roll to roll continuous production process not only requires fast film removal time, clean and complete residue free (no hole plugging phenomenon) solidified resist in small hole, and requires the size of the whole plate film removal piece to be very small. Because if the size of the film removal piece is too large, it will frequently occur that the large size film removal piece wraps the roller, which seriously affects the production efficiency of the production line.

[0009] In addition, there are also a number of rigid circuit board manufacturers with precision circuit using wet film pasting process to make circuit board, which generally has more large through holes (4-6mm round holes or special-shaped holes) on the rigid substrate. Such substrate and process conditions require dry film resist to have good wet pressing resolution and adhesion, and excellent wet pressing hole covering performance and flexibility. For the manufacturer of photosensitive dry film resist, if the photosensitive dry film resist product of each formula can take into account multiple key performance requirements and meet the production requirements of multiple different downstream flexible or rigid circuit board manufacturers, it can greatly improve the production efficiency and cutting yield of photosensitive dry film resist and reduce production cost, etc.

[0010] On this basis, it is of great significance to research and develop a photocurable resin composition with good wet pressing resolution and adhesion, fast film removal speed, clean and complete residue free (no hole plugging phenomenon) solidified resist in small hole, small film removal piece size, and suitable for soft plate roll to roll continuous production process, and excellent wet pressing hole covering performance and flexibility.

[0011] Therefore, for the wet film pasting process, optimizing the core components of the photosensitive dry film resist, obtaining a photosensitive dry film resist with excellent comprehensive performance that can meet the key performance requirements of the production of flexible circuit board with precision circuit and rigid circuit board with precision circuit, is an urgent research topic that needs to be solved and has great practical significance. SUMMARY

[0012] The main purpose of the present application is to provide a photocurable resin composition, its application and a photosensitive dry film resist layer stack, to solve the problem that the existing photosensitive dry film resist in the prior art cannot have good wet pressing resolution, adhesion, wet pressing hole covering performance and flexibility, and has slow film removal speed, easy residue and is difficult to be applied to wet film pasting process and soft plate roll to roll continuous production process.

[0013] In order to achieve the above purpose, the present application provides a photocurable resin composition, which comprises: alkali-soluble resin, photopolymerization monomer, photosensitizer and additive; the alkali-soluble resin comprises compounds represented by general formula (I) and general formula (II):

[0014]

[0015] wherein R1 and R2 are independently selected from H or C1-C4 alkyl; R3 is selected from C1-C 18 substituted or unsubstituted straight chain or branched alkyl, C7-C 14 aryl-substituted alkyl, C5-C 14 alkyl-substituted or unsubstituted cycloalkyl, hydroxy-substituted C1-C 18 straight chain or branched alkyl, or C1-C4 straight chain or branched alkyl-substituted amino; R4 is selected from H, C1-C3 alkyl, C1-C3 alkoxy, amino or halogen atom, and z1 corresponds to the number of substitution of R4 in the segment being any integer from 0 to 5; R4' is selected from H or C1-C4 alkyl; the content of x1 corresponding segment is 27-40 wt%, the content of y1 corresponding segment is 20-73 wt%, and the content of z1 corresponding segment is 0-40 wt% based on the percentage content of the molecular weight of the compound represented by general formula (I);

[0016]

[0017] wherein R5, R6, R8 are independently selected from H or C1-C4 alkyl; R7 is selected from C1-C 18 substituted or unsubstituted straight chain or branched alkyl, C7-C 14 aryl-substituted alkyl, C5-C 14 alkyl-substituted or unsubstituted cycloalkyl, hydroxy-substituted C1-C 18 straight chain or branched alkyl; R9 is selected from one of the following groups:

[0018]

[0019] R 10 is selected from C2-C 10 straight chain or branched alkylene, n is any integer from 2 to 5; the content of x2 corresponding segment is 22-27 wt%, the content of y2 corresponding segment is 21-65 wt%, and the content of z2 corresponding segment is 10-50 wt% based on the percentage content of the molecular weight of the compound represented by general formula (II).

[0020] In order to achieve the above-mentioned purpose, another aspect of the present application further provides an application of the above-mentioned photocuring resin composition provided by the present application in the field of photocuring.

[0021] Still another aspect of the present application provides a photosensitive dry film resist laminated body comprising a support layer and a resist layer prepared from the above-mentioned photocuring resin composition provided by the present application.

[0022] By using the technical solution of the present application, the z2 corresponding segment of the compound of the general formula (II) contains an amide group and an ester group, which can improve the flexibility thereof, and the resist prepared by using the photocuring composition containing the alkali-soluble resin has excellent hole covering property, thereby improving the yield of products; meanwhile, the z2 corresponding segment of the compound of the general formula (II) also contains a hydroxyl group, according to the principle of "like dissolves like", the introduction of the polar group in the alkali-soluble resin can significantly improve the reaction rate of the photocuring resin composition in the alkaline aqueous solution, thereby shortening the time for the stripping film to be peeled off from the surface of the copper substrate, and the introduction of the polar group can also increase the reaction sites of the photocuring resin composition with water, thereby achieving the effect of reducing the size of the stripping film, and the resist prepared by using the photocuring composition containing the alkali-soluble resin is suitable for the soft roll-to-roll continuous production process, and can inhibit the occurrence of the film winding around the roller. In addition, the introduction of the polar group in the alkali-soluble resin can also enhance the bonding force between the photocuring resin composition and the copper substrate or the PET substrate, and improve the adhesion of the photocuring resin composition, thereby ingeniously solving the contradiction between the stripping performance (no hole plugging phenomenon) and the adhesion. Compared with other ranges, the limitation of x2, y2 and z2 in the compound of the general formula (II) in the above ranges is beneficial to improving the flexibility, thereby improving the hole covering property of the resist and the yield of products.

[0023] The content of the x1 corresponding segment in the compound of the general formula (I) is high, which can improve the stripping time and the size of the stripping fragments, thereby significantly improving the hole plugging phenomenon of the resist prepared by using the photocuring composition containing the alkali-soluble resin, and the content of the x1 corresponding segment and the z1 corresponding segment is high, which can significantly improve the wet pressure resolution capability of the photocuring resin composition and the adhesion thereof to the surface of the copper substrate, especially the adhesion to the surface of the flexible substrate with low roughness.

[0024] The alkali-soluble resin in the present application includes the compounds of the general formula (I) and the general formula (II), and the use of the two in combination can exert their synergistic effect, the present application can significantly improve the various performances of the photocuring resin composition by optimizing the molecular structure and introducing the above specific functional groups, so that it is suitable for the wet film pasting process and the soft roll-to-roll continuous production process, and can meet the production requirements of the precision circuit flexible board and the rigid board, improve the product yield, significantly improve the production efficiency in the manufacture of ITO components in the fields of PCB manufacturing, lead frame manufacturing, semiconductor packaging and flat panel display, and reduce the production cost. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the application, and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:

[0026] Figure 1 A schematic diagram of a sample of a wet cover hole performance evaluation substrate used in the present application is shown. DETAILED DESCRIPTION

[0027] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments.

[0028] As described in the background, the existing photosensitive dry film resist has the problems of good wet pressure resolution, adhesion performance, wet pressure cover hole performance and flexibility, slow film removal speed, easy to remain, and difficult to be applied to wet film pasting process and soft plate roll-to-roll continuous production process. In order to solve the above technical problems, the present application provides a photocurable resin composition, which comprises: an alkali-soluble resin, a photopolymerization monomer, a photosensitizer and an additive; the alkali-soluble resin comprises compounds represented by general formula (I) and general formula (II):

[0029]

[0030] wherein R1 and R2 are independently selected from H or C1-C4 alkyl; R3 is selected from C1-C 18 substituted or unsubstituted linear alkyl or branched alkyl, C7-C 14 aryl-substituted alkyl, C5-C 14. alkyl-substituted or unsubstituted cycloalkyl, hydroxy-substituted C1-C 18 linear alkyl or branched alkyl, or C1-C4 linear alkyl or branched alkyl-substituted amino; R4 is selected from H, C1-C3 alkyl, C1-C3 alkoxy, amino or halogen atom, and z1 corresponds to the substitution number of R4 in the chain segment is any integer from 0 to 5; R4' is selected from H or C1-C4 alkyl; the content of x1 corresponding to the chain segment is 27-40 wt%, the content of y1 corresponding to the chain segment is 20-73 wt%, and the content of z1 corresponding to the chain segment is 0-40 wt% based on the percentage content of the molecular weight of the compound represented by general formula (I);

[0031]

[0032] wherein R5, R6, R8 are independently selected from H or C1-C4 alkyl; R7 is selected from C1-C 18 substituted or unsubstituted linear alkyl or branched alkyl, C7-C 14 aryl-substituted alkyl, C5-C14 alkyl-substituted or unsubstituted cycloalkyl, hydroxy-substituted C1-C 18 linear alkyl or branched alkyl; R9 is selected from one of the following groups:

[0033]

[0034] R 10 selected from C2-C 10 linear alkylene or branched alkylene, n is any integer from 2 to 5; x2 corresponds to the content of the segment of 22-27wt%, y2 corresponds to the content of the segment of 21-65wt%, and z2 corresponds to the content of the segment of 10-50wt% based on the percentage content of the molecular weight of the compound of general formula (II).

[0035] The segment of z2 in the compound of general formula (II) contains amide and ester groups, which can improve its flexibility, and the resist prepared by using the alkali-soluble resin containing the same has excellent hole covering property, thereby improving the yield of the product; meanwhile, the segment of z2 in the compound of general formula (II) also contains hydroxyl groups, according to the principle of "like dissolves like", the introduction of polar groups in the alkali-soluble resin can significantly improve the reaction rate of the photocuring resin composition in the alkaline aqueous solution, thereby shortening the time for the stripping film to be peeled off from the surface of the copper substrate, and the introduction of polar groups can also increase the reaction sites with water, thereby achieving the effect of reducing the size of the stripping film. The resist prepared by using the photocuring composition containing the alkali-soluble resin is suitable for the soft roll-to-roll continuous production process, and can inhibit the phenomenon of film winding around the roller. In addition, the introduction of polar groups in the alkali-soluble resin can also enhance the adhesion between the photocuring resin composition and the copper substrate or PET substrate, and improve the adhesion performance of the photocuring resin composition, thereby skillfully solving the contradiction between the stripping performance (no hole plugging phenomenon) and the adhesion performance. Compared with other ranges, the limitation of x2, y2 and z2 in the compound of general formula (II) in the above ranges is beneficial to improve its flexibility, and further improve the hole covering property of the resist and the yield of the product.

[0036] The content of the segment of x1 in the compound of general formula (I) is high, which can improve the stripping time and the size of the stripping fragments, thereby significantly improving the hole plugging phenomenon of the resist prepared by using the photocuring composition containing the alkali-soluble resin. Meanwhile, the contents of the segments of x1 and z1 are high, which can significantly improve the wet stripping ability of the photocuring resin composition and its adhesion to the surface of the copper substrate, especially the adhesion performance to the surface of the flexible substrate with low roughness.

[0037] The alkali-soluble resin in the present application includes compounds represented by general formula (I) and general formula (II), and the use of the two compounds in combination can exert their synergistic effect. The present application can significantly improve the performance of the photocuring resin composition by optimizing the molecular structure and introducing the specific functional groups described above, so that it is suitable for wet film pasting process and soft plate roll-to-roll continuous production process, and can meet the production needs of precision circuit flexible board and rigid board, improve product yield, significantly improve production efficiency in the manufacture of ITO components in the fields of PCB manufacturing, lead frame manufacturing, semiconductor packaging, flat panel display, and reduce production cost.

[0038] In a preferred embodiment, the weight ratio of the compound represented by general formula (I) to the compound represented by general formula (II) is (15-35):(15-40). Compared with other ranges, limiting the weight ratio of the compound represented by general formula (I) to the compound represented by general formula (II) in the above range is beneficial to exert the synergistic effect of the two compounds, improve the flexibility of the alkali-soluble resin, thereby improve the hole covering property of the photocuring resin composition, further improve the reaction rate of the photocuring resin composition in the alkaline aqueous solution, shorten the time for the film removal to be peeled off from the surface of the copper substrate; at the same time, it is also beneficial to reduce the film removal size, improve the bonding force between the photocuring resin composition and the copper substrate, and facilitate its application in the soft plate roll-to-roll continuous production process.

[0039] In order to further shorten the film removal time, further reduce the size of the film removal fragments, further improve the hole plugging phenomenon of small holes, further reduce the residue of the photocuring resin composition, and further improve the toughness of the alkali-soluble resin and the wet hole covering ability of the photocuring resin composition, preferably, the acid value of the compound represented by general formula (I) is 210-310 mgKOH / g.

[0040] In order to further shorten the development time and the film removal time, further improve the flexibility of the alkali-soluble resin and the hole covering and filling property of the photocuring resin composition, preferably, the acid value of the compound represented by general formula (II) is 170-210 mgKOH / g.

[0041] In a preferred embodiment, in the compound represented by general formula (I), R1 includes but is not limited to H or methyl, R2 includes but is not limited to H or methyl, and R3 includes but is not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, isooctyl, C 12 straight-chain alkyl, C 18linear alkyl, benzyl, glycidoxypropyl-substituted methylene, hydroxyethyl, hydroxypropyl, hydroxybutyl, -N(CH3)2, or -N(C2H5)2, R4 includes but is not limited to H or methyl, and z1 corresponds to the number of substitutions of R4 in the segment, which is 0 or 1, and R4' includes but is not limited to H or methyl. The use of the above-mentioned types of R1, R2, R3, R4 groups is conducive to further shortening the film removal time, further reducing the size of the film removal fragments, and further improving the comprehensive performance of the light-cured resin composition, such as the plug hole phenomenon of the small hole, the reduction of the residual light-cured resin composition, and the wet pressure analysis capability and the cap performance of the light-cured resin composition.

[0042] In a preferred embodiment, in the compound represented by general formula (II), R5, R6, R8 each independently includes but is not limited to H or methyl, and R7 includes but is not limited to methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, isooctyl, C 12 linear alkyl, C 18 linear alkyl, benzyl, glycidoxypropyl-substituted methylene, hydroxyethyl, hydroxypropyl, or hydroxybutyl, R 10 includes but is not limited to ethylene, propylene, or decylene. The use of the above-mentioned types of R5, R6, R7, R8 and R 10 groups is conducive to improving the flexibility of the alkali-soluble resin and the comprehensive performance of the light-cured resin, such as the wet pressure analysis capability and the cap performance of the light-cured resin.

[0043] In a preferred embodiment, the weight average molecular weight of the compound represented by general formula (I) is 30000-80000, and the molecular weight distribution index is 1.3-2.5. The weight average molecular weight and the molecular weight distribution index of the compound represented by general formula (I) include but are not limited to the above-mentioned ranges, and the limitation within the above-mentioned ranges is conducive to improving the film-forming performance of the light-cured resin composition and facilitating the wet film pasting process and the roll-to-roll continuous production process.

[0044] In order to reduce the occurrence of plug and flow phenomena, preferably, the polymerization conversion rate of the compound represented by general formula (I) is ≥97%.

[0045] In a preferred embodiment, the weight average molecular weight of the compound represented by general formula (II) is 60000-90000, and the molecular weight distribution index is 1.3-2.5. The weight average molecular weight and the molecular weight distribution index of the compound represented by general formula (II) include but are not limited to the above-mentioned ranges, and the limitation within the above-mentioned ranges is conducive to improving the resolution of the light-cured resin composition, improving its cap performance and wet pressure analysis performance, reducing the size of the film removal fragments, and facilitating the roll-to-roll continuous production process.

[0046] In order to reduce the occurrence of plug and flow phenomena, preferably, the polymerization conversion rate of the compound represented by general formula (II) is ≥97%.

[0047] It should be noted that the weight average molecular weight in the present application is determined by gel permeation chromatography (GPC) according to SN / T 4183-2015.

[0048] In a preferred embodiment, the photocuring resin composition comprises, by weight parts, 50-65 parts of alkali-soluble resin, 34-49 parts of photopolymerizable monomer, 0.3-5 parts of photosensitizer and 0.5-5 parts of additive. Compared with other ranges, limiting the amount of each component in the photocuring resin composition in the above range is advantageous to improve the comprehensive performance of the photocuring resin composition such as wet pressing analysis, adhesion performance, wet pressing hole performance, etc., facilitating the wet film pasting process and roll-to-roll continuous production process.

[0049] In a preferred embodiment, the photopolymerizable monomer comprises one or more of the following compounds represented by general formula (B1), (B2), (B3), (B4), (B5), (B6):

[0050]

[0051] wherein m1 and m2 are independently any integer from 1 to 30, n1 and n2 are independently any integer from 0 to 20, m1+m2 is any integer from 2 to 30, n1+n2 is any integer from 0 to 20, the n1 corresponding segment and the m1 corresponding segment can be randomly arranged or block arranged, and the n2 corresponding segment and the m2 corresponding segment can be randomly arranged or block arranged;

[0052]

[0053] wherein m3 and m4 are independently any integer from 1 to 30, m3+m4 is any integer from 15 to 30,

[0054]

[0055] wherein a1 and b1 are independently any integer from 0 to 20, and the a1 corresponding segment and the b1 corresponding segment can be randomly arranged or block arranged;

[0056]

[0057] wherein a2 and c2 are independently any integer from 0 to 20, b2 is any integer from 1 to 20, a2+c2 is any integer from 2 to 30, and the a2 corresponding segment, the b2 corresponding segment and the c2 corresponding segment can be randomly arranged or block arranged;

[0058]

[0059] wherein b3 is any integer from 1 to 20, a3 and c3 are independently any integer from 1 to 20, a3 + c3 is any integer from 2 to 30, b3 is any integer from 2 to 20, and the a3 corresponding segment, b3 corresponding segment and c3 corresponding segment can be arranged randomly or in blocks;

[0060]

[0061] wherein a4 is any integer from 2 to 30, b4 is any integer from 0 to 20, and the a4 corresponding segment and b4 corresponding segment can be arranged randomly or in blocks;

[0062] In the compounds represented by general formula (B1), (B2), (B3), (B4), (B5) and (B6), R b independently include, but are not limited to, H or C1-C4 alkyl, and EO represents ethoxy and PO represents propoxy.

[0063] Compared with other types of photopolymerization monomers, the above-mentioned type of photopolymerization monomer contains ethoxy or a combination of ethoxy and propoxy, which is conducive to improving the water absorption and hydrophilicity of the photopolymerization monomer, thereby being conducive to improving the wet compression filling performance of the photocuring resin composition, and further being conducive to reducing the occurrence of the hole plugging phenomenon.

[0064] In order to further improve the hydrophilicity of the photopolymerization elastomer, thereby further improving the wet compression filling performance of the photocuring resin composition and reducing the occurrence of the hole plugging phenomenon, preferably, the content of the compound represented by general formula (B2) is 5-15 wt% based on the total weight of the photocuring resin composition.

[0065] In a preferred embodiment, the photopolymerization monomer further includes a monofunctional, bifunctional or polyfunctional (meth)acrylate type olefinic unsaturated double bond monomer other than the above-mentioned structural formula, and more preferably one or more of the group consisting of lauryl (meth)acrylate, stearyl (meth)acrylate, nonyl phenol acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, bisphenol A di(meth)acrylate, polyethylene glycol (propylene glycol) di(meth)acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and polyurethane acrylate. Compared with other types, the use of the above-mentioned type of photopolymerization monomer is conducive to reducing the tendency of glue overflow, and at the same time is conducive to improving the photosensitivity and resolution of the photocuring resin composition.

[0066] In a preferred embodiment, the photosensitizer comprises one or more of a photoinitiator or a hexaarylbiimidazole photoinitiator of general formula (C1) or general formula (C2) and a sensitizer:

[0067]

[0068] wherein R c including but not limited to H, C1-C6 alkyl, C2-C3 haloalkyl, C1-C3 alkoxy, substituted or unsubstituted aryl, haloaryl, or pyridyl; R c ’ including but not limited to C3-C 10 straight chain alkylene.

[0069] To further improve the photosensitivity of the photocurable resin composition in the wavelength range of 350-420 nm, preferably, Rc includes but is not limited to methyl, ethyl, phenyl, chloroethyl, methoxy, ethoxy, methylphenyl, ethylphenyl, n-propylphenyl, n-butylphenyl, t-butylphenyl, methoxyphenyl, ethoxyphenyl, chlorophenyl.

[0070] To further improve the photosensitivity of the photocurable resin composition in the wavelength range of 350-420 nm, further improve the photosensitivity, resolution, and adhesion to the surface of the substrate of the photocurable resin composition, in a preferred embodiment, the sensitizer includes but is not limited to one or more of the group consisting of aromatic ketone compounds, anthraquinone compounds, coumarin compounds, N-phenyl glycine compounds, anthracene compounds, pyrazoline compounds, amino acid compounds, quinone compounds, phenylethanone compounds, acyl phosphine oxide compounds, benzoin compounds, benzoin ether compounds, dialkyl ketal compounds, thioxanthone compounds, and dialkylamino benzoate compounds; more preferably one or more of the group consisting of 5-(4-methoxyphenyl)-3-[2-(4-methoxyphenyl)vinyl]-1-phenyl-pyrazoline, 5-phenyl-3-biphenyl-1-phenyl-pyrazoline, 1-phenyl-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)-pyrazoline, 1-(4-(benzoxazol-2-yl)phenyl)-3-(4-tert-butylstyryl)-5-(4-tert-butylphenyl)-pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-butylphenyl)-pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-octylphenyl)-pyrazoline, N-phenyl glycine, N-methyl-N-phenyl glycine, N-ethyl-N-phenyl glycine, benzophenone, Michler's ketone [4,4'-bis(dimethylamino)benzophenone], 4,4'-bis(diethylamino)benzophenone, and 4-methoxy-4'-dimethylaminobenzophenone.

[0071] In a preferred embodiment, the compound of general formula (C1) includes, but is not limited to, one or more of the group consisting of 9-methylacridine, 9-ethylacridine, 9-phenylacridine, 9-chloroethylacridine, 9-methoxyacridine, 9-ethoxyacridine, 9-(4-methylphenyl)acridine, 9-(4-ethylphenyl)acridine, 9-(4-n-propylphenyl)acridine, 9-(4-n-butylphenyl)acridine, 9-(4-t-butylphenyl)acridine, 9-(4-methoxyphenyl)acridine, 9-(4-ethoxyphenyl)acridine, 9-m-tolylacridine, 9-o-tolylacridine, 9-p-tolylacridine, 9-p-chlorophenylacridine. Compared to other types, using the above type of compound of general formula (C1) as the main component of the photosensitizer is conducive to further improving the photosensitivity of the photocuring resin composition in the wavelength range of 350-420 nm.

[0072] In a preferred embodiment, the compound of general formula (C2) includes, but is not limited to, 1,7-bis(9,9'-acridinyl)heptane. Compared to other types, using the above type of compound of general formula (C2) as the main component of the photosensitizer is conducive to further improving the photosensitivity of the photocuring resin composition in the wavelength range of 350-420 nm.

[0073] In order to further improve the photosensitivity of the photocuring resin composition in the wavelength range of 350-420 nm, and to further adapt to conventional UV and LED exposure machines and laser direct imaging (LDI) exposure machines, thereby further improving the photosensitivity, resolution capability, and adhesion to the substrate surface of the photocuring resin composition, preferably, the ratio of the total weight of the compound of general formula (C1) and the sensitizer to the sum of the weight of the alkali-soluble resin and the photopolymerizable monomer is (0.3-2):100.

[0074] In order to further improve the photosensitivity of the photocuring resin composition in the wavelength range of 350-420 nm, and to further improve the photosensitivity, resolution capability, and adhesion to the substrate surface of the photocuring resin composition, and its adaptability to conventional UV and LED exposure machines, preferably, the hexaarylbiimidazole photoinitiator includes, but is not limited to, one or more of the group consisting of 2-(o-chlorophenyl)-4,5-diphenylimidazole dimer, 2-(o-chlorophenyl)-4,5-di(methoxyphenyl)imidazole dimer, 2-(o-fluorophenyl)-4,5-diphenylimidazole dimer, 2-(o-methoxyphenyl)-4,5-diphenylimidazole dimer, 2-(p-methoxyphenyl)-4,5-diphenylimidazole dimer, 2,2',4-tris(2-chlorophenyl)-5-(3,4-dimethoxyphenyl)-4',5'-diphenyl-1,1'-biimidazole.

[0075] In a preferred embodiment, the additive includes, but is not limited to, one or more of the group consisting of a color former, a dyeing agent, a plasticizer, a photothermal stabilizer, an adhesion promoter, a leveling agent, an antifoaming agent, a polymerization inhibitor. The introduction of the above-mentioned additive in the photocuring resin composition is beneficial to the production process and improves the processability. The above-mentioned additive of the kind can be compounded in any ratio.

[0076] The second aspect of the present application further provides an application of the above-mentioned photocuring resin composition provided by the present application in the field of photocuring. The above-mentioned photocuring resin composition provided by the present application has excellent hole covering property, film removing property and adhesion property, and is suitable for soft board roll-to-roll continuous production process. The application of the above-mentioned photocuring resin composition in the field of photocuring can meet the production requirements of both precision circuit flexible board and rigid board, improve product yield, and significantly improve the production efficiency and reduce the production cost in the manufacture of ITO components and the like in the fields of PCB manufacturing, lead frame manufacturing, semiconductor packaging and flat panel display.

[0077] The third aspect of the present application further provides a photosensitive dry film resist laminated body, which comprises a support layer and a resist layer, and the resist layer is prepared from the above-mentioned photocuring resin composition provided by the present application. The above-mentioned photocuring resin composition provided by the present application has excellent hole covering property, film removing property and adhesion property, and is suitable for soft board roll-to-roll continuous production process. The application of the above-mentioned photocuring resin composition in the preparation of the resist layer of the photosensitive dry film resist laminated body can meet the production requirements of both precision circuit flexible board and rigid board, improve product yield, and significantly improve the production efficiency and reduce the production cost in the manufacture of ITO components and the like in the fields of PCB manufacturing, lead frame manufacturing, semiconductor packaging and flat panel display.

[0078] The present application will be further described in detail below in combination with specific examples, which cannot be understood as limiting the scope of the present application.

[0079] (I) Alkali-soluble resin preparation example

[0080] The synthesis method of the alkali-soluble resin (A1-1) used in the examples of the present application comprises:

[0081] The monomers of methyl methacrylate, methyl methacrylate, butyl methacrylate and styrene are mixed in a weight ratio of 30:30:10:30, mixed with 1.0 g of azobisisobutyronitrile (AIBN) initiator, 90 g of butanone, 15 g of ethanol to obtain a mixed solution; 35% mass fraction of the mixed solution is added into a three-necked flask with nitrogen protection and condensation reflux device through a peristaltic pump, the oil bath is heated to 80°C, after stirring for 1 h, the remaining mixed solution is added dropwise, and the addition is completed within 3 h; after continuing to react for 4 h, the temperature is increased to 90°C, and 5 g of butanone solution containing 0.2 g of AIBN initiator is added twice with an interval of 1 h, and after the dropwise addition is completed, the temperature is kept for 2 h, the reaction is stopped, and the alkali-soluble resin (A1-1) is obtained.

[0082] The weight average molecular weight and molecular weight distribution index thereof are tested by GPC method, and the solid content thereof is obtained by drying and weighing.

[0083] The synthesis method of the alkali-soluble resin (A2-1) used in the embodiments of the present application comprises:

[0084] (1) Preparation of a semi-addition product of dihydric alcohol and isocyanate: 20 g of butanone, 9.1 g of ethylene glycol (1.15 equivalents) are added into a three-necked flask, nitrogen is introduced, 6.66 mg of dibutyltin dilaurate and 22.2 g of toluene diisocyanate (1.0 equivalent) are slowly added dropwise under stirring, and the reaction is carried out at 45°C for 6 h until no change in -NCO content is detected, and the reaction is stopped, to obtain a semi-addition product solution of dihydric alcohol and isocyanate, which is sealed and stored for use in the next step as soon as possible;

[0085] (2) Preparation of alkali-soluble resin (A2-1): 30 g of butanone is added into a three-necked flask, nitrogen is introduced, and the temperature is increased to 80°C, and a mixture composed of 25 g of methyl methacrylate, 30 g of methyl methacrylate, 14.8 g of hydroxyethyl methacrylate, 0.7 g of AIBN initiator, 30 g of butanone, 10 g of ethanol is added dropwise within 1 h, and the product system of the acrylic resin containing carboxyl and hydroxyl groups is prepared by reacting at 80°C for 12 h; the product system is cooled to room temperature, 2 drops of dibutyltin dilaurate, 10 g of butanone and an appropriate amount of p-hydroxyanisole polymerization inhibitor (so that the content of the polymerization inhibitor in the system is 100-200 ppm) are added, the temperature is increased to 60°C, and then the semi-addition product of dihydric alcohol and isocyanate prepared in step (1) is added dropwise, the addition is completed within 1 h, and after the dropwise addition is completed, the stirring reaction is continued at 60°C for 4 h, the reaction is stopped when the 2274 cm-1 absorption peak of -NCO in the infrared spectrum disappears, and the alkali-soluble resin (A2-1) is obtained.

[0086] The base-soluble resins A1-1 to A1-5 were synthesized according to the formulations shown in Table 1 as examples, the base-soluble resins A2-1 to A2-6 were synthesized according to the formulations shown in Table 2 as examples, and the base-soluble resins AX-1 to AX-4 were synthesized according to the formulations shown in Table 3 as comparative examples.

[0087] Table 1

[0088]

[0089] Table 2

[0090]

[0091]

[0092] Table 3

[0093]

[0094] (II) Formulation Examples of the photocurable resin composition

[0095] Each component was mixed in proportion according to the formulations shown in Tables 4, 5 and 6 below, 40 parts by weight of butanone was added, and then stirred well until completely dissolved to prepare a resin composition solution having a solid content of 40 wt%. It was uniformly coated on the surface of a PET support film having a thickness of 15 μm using a coater, and then placed in an oven at 90°C for 10 min to form a photosensitive dry film resist layer having a thickness of 30 μm, which appeared blue-green under a yellow light. Then, a polyethylene film protective layer having a thickness of 20 μm was attached to the surface thereof to obtain a photosensitive film having a 3-layer structure.

[0096] Photopolymerizable monomer:

[0097] B-1: (20) ethoxylated bisphenol A diacrylate (Mitsubishi Rayon), corresponding to general formula (B2), m3+m4=20;

[0098] B-2: (30) ethoxylated bisphenol A diacrylate (Mitsubishi Rayon), corresponding to general formula (B2), m3+m4=30;

[0099] B-3: (10) ethoxylated bisphenol A diacrylate (Mitsubishi Rayon), corresponding to general formula (Bl), ml+ m2=10, nl+ n2=0;

[0100] B-4: (10) ethoxylated (4) propoxylated bisphenol A diacrylate (Mitsubishi Rayon), corresponding to general formula (Bl), ml+ m2=10, nl+ n2=4;

[0101] B-5: polyethylene glycol (400) dimethacrylate (Mitsubishi Rayon), corresponding to general formula (B3), al=9, bl=0;

[0102] B-6: Polypropylene glycol (700) (6) ethoxylated dimethacrylate (Miyoshi), corresponding to general formula (B4), b2 = 12, a2 + c2 = 6;

[0103] B-7: (8) ethoxylated nonyl phenol acrylate (Miyoshi), corresponding to general formula (B6), a4 = 8, b4 = 0;

[0104] Photosensitizer:

[0105] C-1: 9-phenylacridine;

[0106] C-2: N-phenylglycine;

[0107] C-3: 2,2'-bis(2-chlorophenyl)-4,4'-5,5'-tetraphenyl-1,1'-biimidazole (Changzhou Qiangli Electronic New Materials);

[0108] C-4: 5-(4-methoxyphenyl)-3-[2-(4-methoxyphenyl)vinyl]-1-phenyl-pyrazoline;

[0109] Additive:

[0110] D-1: Brilliant green pigment (Shanghai Bailingwei Chemical Technology Co., Ltd.);

[0111] D-2: Leuco crystal violet (Shanghai Bailingwei Chemical Technology Co., Ltd.);

[0112] D-3: p-methylbenzenesulfonamide (Shanghai Tixi'ai Chemical Industry).

[0113] Table 4

[0114]

[0115] Table 5

[0116]

[0117] Table 6

[0118]

[0119] The following describes the sample preparation method (including film pasting, exposure, development, and copper electroplating) of the examples and comparative examples, the sample evaluation method, and the evaluation results.

[0120] (1) Sample preparation method

[0121]

Substrate

[0122] 1. Substrate for hole plugging test, film removal time, and film removal fragment evaluation:

[0123] A 50 μm thick, two-sided flexible copper clad laminate with 200 small diameter through holes of 0.1 mm diameter laminated with 18 μm rolled copper foil and 10 μm copper plating.

[0124] 2. Substrate for evaluating photosensitivity, wet pressing resolution, wet pressing adhesion, and flexibility:

[0125] A 50 μm thick, two-sided flexible copper clad laminate without small diameter through holes laminated with 18 μm rolled copper foil and 10 μm copper plating.

[0126] 3. Substrate for evaluating wet pressing hole covering performance:

[0127] A 1.6 mm thick rigid irregular hole plate, the irregular hole plate used for testing has circular holes of 6.0 mm, 5.0 mm, and 4.0 mm diameter and irregular holes, and the specific pattern is shown in Figure 1 After the film is attached for 30 minutes, exposure is performed at the exposure energy for a photosensitive grid number of 18, and after exposure for 30 minutes, development is performed for a time period four times the shortest development time, the broken hole rate is counted, and the hole covering performance is evaluated.

[0128]

Wet film attachment

[0129] 1. Wet pressing flexible substrate film attachment:

[0130] a. The two-sided flexible copper clad laminate (FCCL) is cut into a 250 mm x 280 mm rectangle, and no polishing, etching, or other pretreatment operations are performed; b. Deionized water or distilled water is added to the sponge roller, and then the flexible substrate is passed through the sponge roller to uniformly coat a layer of water film on the copper surface; c. The film attachment temperature of the film attachment machine is set to 100°C, the pressure is 4.0 kg / cm 2 , and the speed is 1.0 m / min.

[0131] 2. Wet pressing film attachment of rigid substrate for hole covering test

[0132] a. The rigid substrate with an irregular hole plate is polished by a polishing machine, washed, etched, dried, and subjected to other pretreatment operations to obtain a bright and fresh copper surface; b. Deionized water or distilled water is added to the sponge roller, and then the flexible substrate is passed through the sponge roller to uniformly coat a layer of water film on the copper surface; c. The film attachment temperature of the film attachment machine is set to 100°C, the pressure is 4.0 kg / cm 2 , and the speed is 1.0 m / min.

[0133]

Exposure

[0134] 1. Exposure is performed using a laser direct imaging (LDI) exposure machine

[0135] After the sample is pasted for more than 15 minutes, the resolution and adhesion performance are tested by using a Japan Adtec exposure machine for exposure, a model: IP-6, a wavelength 405 nm laser direct imaging (LDI) exposure machine for exposure, a stouffer 41-step exposure ruler for photosensitivity test, and the exposure number is controlled at 18 steps.

[0136] 2. Exposure by using a conventional UV exposure machine

[0137] After the sample is pasted for more than 15 minutes, the resolution and adhesion performance are tested by using a Japan Adtec exposure machine for exposure, a model: IP-6, a wavelength 405 nm laser direct imaging (LDI) exposure machine for exposure, a stouffer 41-step exposure ruler for photosensitivity test, and the exposure number is controlled at 18 steps.

[0138] 3. Exposure by using a conventional LED exposure machine

[0139] After the sample is pasted for more than 15 minutes, the resolution and adhesion performance are tested by using a LED exposure machine, a model: Hongshengxiang HSX-LED S5 for exposure, an exposure intensity of 40% for exposure, a stouffer 41-step exposure ruler for exposure number test, and the exposure number is controlled at 18-19 steps.

[0140]

Development

[0141] After exposure, the sample is left for more than 15 minutes, the development temperature is 30°C, the pressure is 1.2 kg / cm 2 , the developing solution is 1 wt% sodium carbonate aqueous solution, the development time is 1.5-2.0 times of the minimum development time, and after development, the sample is washed with water and dried. The minimum time required for completely dissolving the unexposed part of the resist layer is taken as the minimum development time.

[0142]

Acid etching

[0143] The copper plate after development is subjected to etching process, the etching solution is copper chloride, the etching speed is 1.0 m / min, the etching temperature is 48°C, the spray pressure is 1.5 bar, the specific gravity is 1.3 g / mL, the acidity is 2 mol / L, the copper ion is 140 g / L, and the etching machine model is Dongguan Universe GL181946.

[0144]

Stripping

[0145] The stripping solution is NaOH, the concentration is 3.0 wt%, the temperature is 50°C, the pressure is 1.2 kg / cm 2 , the stripping time is 1.5-2.0 times of the minimum stripping time, and after stripping, the sample is washed with water and dried.

[0146] (2) Evaluation method

[0147]

Photosensitivity and matching evaluation of different exposure machines

[0148] After the film was attached, the sample was left to stand for 15 minutes or more, and exposed using an Adtec IP-6 405 nm LDI exposure machine, a Jisang Technology M-552 type UV light exposure machine, and a Hongshangxiang HSX-LEDS5 LED exposure machine. The photosensitivity was tested using a stouffer 41-step exposure scale. After exposure, the unexposed portions were removed by spraying a 1 wt% sodium carbonate aqueous solution at 30°C for 2.0 times the minimum development time. After this operation, a cured film formed of a cured product of the photosensitive resin composition was formed on the copper surface of the substrate. The number of remaining segments of the stage exposure table obtained as the cured film was 18 to 19 steps at an exposure amount (mJ / cm 2 ), and the photosensitivity of the photosensitive resin composition was evaluated. The smaller the exposure energy value, the better the photosensitivity.

[0149] The evaluation criteria were as follows: "O" indicated that the LDI exposure machine exposure energy was 20 to 40 mJ / cm 2 , the UV and LED exposure machine exposure energy was 15 to 30 mJ / cm 2 , and there was no resolution failure; "Δ" indicated that the LDI exposure machine exposure energy was 40 to 60 mJ / cm 2 , the UV and LED exposure machine exposure energy was 25 to 50 mJ / cm 2 ; and "X" indicated that the LDI exposure machine exposure energy was > 60 mJ / cm 2 , the UV and LED exposure machine exposure energy was 25 to 50 mJ / cm 2 .

[0150]

Whether there is a hole plugging phenomenon test evaluation

[0151] After the test substrate for testing whether there is a hole plugging phenomenon was completed by wet pressing and film attachment, it was placed at 25°C and 60% relative humidity for 48 hours. The Adtec IP-6 405 nm LDI exposure machine (IP-6 exposure curing depth is good, and it is more difficult to remove the film from the hole) was used to expose the sample at an exposure energy corresponding to 19 steps of the stouffer 41-step exposure scale. The sample was developed and the film was removed according to the above procedure. The ratio of the number of holes that were not completely removed (the number of plugged holes) to the total number of small holes was evaluated according to the following judgment basis.

[0152] The evaluation criteria were as follows: "O" indicated that it was qualified, i.e., there was no hole plugging phenomenon at all, and there was no film debris left on the flexible plate surface, i.e., the number of plugged holes was zero; "Δ" indicated that it was not good, i.e., there was a hole plugging phenomenon, but the ratio of the number of plugged holes was 10% or less; and "X" indicated that it was completely unqualified, i.e., there was a hole plugging phenomenon, the ratio of the number of plugged holes was 10% or more, and there was obvious film debris left on the flexible plate surface.

[0153]

Evaluation of the film peeling time and the film peeling fragment size

[0154] After the test substrate for evaluating the film peeling time and the film peeling fragment is subjected to the wet pressing film pasting, the sample after the film pasting is left to stand for 24 hours, and the Adtec IP-6 405 nm LDI exposure machine is used for exposure. The exposure energy is the energy corresponding to the 19th scale of the stouffer 41-step exposure scale for the sensitivity test. The exposure, development and film peeling are performed, and the film peeling time and the film peeling fragment size of the photosensitive dry film resist are evaluated according to the following judgment basis.

[0155] The evaluation criteria are as follows: "O" indicates that the film peeling time is ≤ 35 s, the film peeling fragment size is 5-15 mm, and it can be applied to the soft plate roll-to-roll continuous process; "Δ" indicates that 35 s > the film peeling time is ≤ 50 s, the film peeling fragment size is 15-30 mm, the film peeling time is relatively long, the film fragment is relatively large, and the production efficiency is relatively low; and "X" indicates that the film peeling time is > 50 s or the film peeling fragment size is > 30 mm, which seriously affects the production efficiency or the use yield.

[0156]

Evaluation of the wet pressing resolution ability

[0157] The substrate for evaluating the wet pressing resolution is left to stand for 24 hours after the wet pressing film pasting, and the Adtec IP-6 405 nm LDI exposure machine is used for exposure. The stouffer 41-step exposure scale is used for the sensitivity test, and the mask with a wiring pattern having an exposed part and an unexposed part and a width of 1:1 is used for exposure. The corresponding sensitivity is 18-19 scales, a 1 wt% sodium carbonate aqueous solution is sprayed at 30°C, and the development time is 2.0 times the minimum development time to remove the unexposed part. The minimum mask width at which the cured resist line is normally formed is taken as the value of the resolution, and the smaller the read number is, the better the wet pressing resolution performance is.

[0158]

Evaluation of the wet pressing adhesion

[0159] The substrate for evaluating the wet pressing adhesion is left to stand for 24 hours after the wet pressing film pasting, and the Adtec IP-6 405 nm LDI exposure machine is used for exposure. The stouffer 41-step exposure scale is used for the sensitivity test, and the mask with a wiring pattern having an exposed part and an unexposed part and a width of n:400 μm is used for exposure. After development for 2 times the minimum development time, the smaller the read number is, the better the adhesion is.

[0160]

Evaluation of the wet pressing hole covering performance

[0161] The wet pressing cover hole performance evaluation substrate - the irregular hole plate, after wet pressing and pasting the film, is allowed to stand for 24 hours, exposed using an Adtec IP-6405nm LDI exposure machine, and exposed at an exposure energy corresponding to a sensitivity of 18-19 grids. After exposure for 30 minutes, the sample is developed for a time twice the minimum developing time. The broken hole rate is calculated to evaluate the wet pressing cover hole performance. The irregular hole mask has higher requirements for the flexibility of the photosensitive dry film than the circular hole mask, and is more difficult to achieve.

[0162] The evaluation criteria are as follows: "O" indicates that the broken hole rate is ≤2% (a few broken holes may be caused by production conditions); "Δ" indicates that 2% > broken hole rate ≤10%; and "X" indicates that the entire plate surface has obvious broken holes.

[0163]

Evaluation of flexibility

[0164] The flexible substrate (FPC) is wet pressed and pasted with the film, and allowed to stand for more than 15 minutes. The sample is exposed using an Adtec IP-6405nm LDI exposure machine, and exposed at an exposure energy corresponding to a sensitivity of 18-19 grids. After exposure for 30 minutes, the sample is developed for a time twice the minimum developing time. The flexible evaluation substrate with the dry film resist stacked on the FPC substrate is obtained. The flexibility is evaluated using a mandrel tester. The flexible evaluation substrate is cut into a 2 cm wide and 10 cm long strip, and rubbed against a cylindrical rod at 180° for 10 rounds. The condition of the dry film resist on the substrate is observed, and the diameter of the rod corresponding to the dry film without glass or cracking is recorded.

[0165] The evaluation criteria are as follows: "O" indicates that the broken hole rate is ≤2% (a few broken holes may be caused by production conditions); "Δ" indicates that 2% > broken hole rate ≤10%; and "X" indicates that the entire plate surface has obvious broken holes.

[0166] (3) The results of the performance evaluation of photosensitivity, whether there are small holes, film removal performance, wet pressing analysis, wet pressing adhesion, wet pressing cover hole, flexibility, etc. are shown in Tables 7 and 8.

[0167] Table 7

[0168]

[0169] Table 8

[0170]

[0171] From the above description, it can be seen that the above-described embodiments of the present application achieve the following technical effects:

[0172] From the comparison of Examples 1 to 10 and Comparative Examples 1 to 8, it can be seen that the photosensitive dry film resists obtained in Examples 1 to 10 all have the following key performances: good wet pressing resolution and adhesion, fast film removal speed, clean and complete removal of the cured resist in the small holes without residue (no hole plugging phenomenon), small film removal piece size, applicability to soft board roll-to-roll continuous production process, and excellent wet pressing hole covering performance and flexibility.

[0173] The photocuring resin compositions obtained in the above Examples 1 to 10 have excellent comprehensive performances, and are stable in application to the wet pressing film pasting process. Therefore, the performances of the photosensitive dry film resists obtained fully meet the performance requirements of the photosensitive dry film resists for the production of flexible and rigid circuit boards with fine lines by using the wet pressing process, and meet the use requirements of the soft board roll-to-roll continuous production process.

[0174] The alkali-soluble resins used in Comparative Examples 1 to 3 are alkali-soluble resins commonly used in photosensitive dry film resists for the production of precision flexible or rigid circuit boards. From the test results, it can be seen that the wet pressing resolution and adhesion are basically satisfactory, but the hole plugging phenomenon is obvious, the film removal time is relatively long, the flexibility and wet pressing hole covering performance are extremely poor, and the production yield and efficiency for the production of precision flexible circuit boards are seriously affected.

[0175] In Comparative Examples 4 to 6, (meth)acrylic long-chain alkyl esters (AX-3 and AX-4) or styrene-containing alkali-soluble resins (AX-2) are compounded in order to improve the film removal performance and reduce the occurrence of the hole plugging phenomenon. From the experimental results, it can be seen that the adhesion of the photocuring resin composition is obviously decreased, which is not suitable for the production of fine line circuit boards, the film removal piece is obviously large, the film removal is difficult, the hole plugging problem is prone to occur, and it is not suitable for the roll-to-roll continuous production process of the board.

[0176] In Comparative Example 7, only alkali-soluble resin A1-1 is used as the alkali-soluble resin. From the experimental results, it can be seen that the photosensitivity, wet pressing resolution and adhesion are normal, but the hole plugging phenomenon is obvious, the film removal time is also long, and the wet pressing hole covering ability and flexibility are extremely poor.

[0177] In Comparative Example 8, only alkali-soluble resin A2-1 is used as the alkali-soluble resin. From the experimental results, it can be seen that the wet pressing hole covering performance and flexibility are relatively good, the hole plugging phenomenon and film removal performance are slightly better than those in Comparative Example 7, but there is still a little hole plugging phenomenon, the film removal piece is slightly large, and the wet pressing resolution and adhesion are slightly decreased.

[0178] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the present application described herein are, for example, capable of orderly execution or performance where

[0179] The preferred embodiments of the application are described above in detail. The application is not limited to the embodiments described above, but can vary and be modified in various ways. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the application should be included in the scope of the protection of the application.

Claims

1. A photocurable resin composition, characterized by, The photo-curable resin composition comprises: an alkali-soluble resin, a photo-polymerization monomer, a photosensitizer and an additive; the alkali-soluble resin comprises compounds represented by general formula (I) and general formula (II): （I）， wherein R1 and R2 are independently selected from H or C1-C4 alkyl; R3 is selected from C1 to C2. 18 Substituted or unsubstituted straight-chain alkyl or branched alkyl, C7-C 14 aryl-substituted alkyl groups, C5-C 14 Alkyl-substituted or unsubstituted cycloalkyl, hydroxy-substituted C1-C2 18 Straight-chain alkyl or branched alkyl, or amino groups substituted with straight-chain alkyl or branched alkyl from C1 to C4; R4 is selected from H, C1-C3 alkyl, C1-C3 alkoxy, amino or halogen atom, and z1 corresponds to the substitution number of R4 in the chain segment being any integer from 0 to 5; R4' is selected from H or C1-C4 alkyl; The content of the x1 corresponding chain segment is 27-40 wt% based on the percentage content of the molecular weight of the compound represented by general formula (I), the content of the y1 corresponding chain segment is 20-73 wt%, and the content of the z1 corresponding chain segment is 0-40 wt%; (I), (II), wherein R5, R6, R8 are independently selected from H or C1-C4 alkyl; R7is selected from the group consisting of C1-C 18 substituted or unsubstituted straight chain or branched chain alkyl, C7-C 14 aryl-substituted alkyl, C5-C 14 alkyl-substituted or unsubstituted cycloalkyl, hydroxy-substituted C1-C 18 straight chain or branched chain alkyl; R9 is selected from one of the following groups: 、 、 、 、 、 、 、 ； R 10 a straight-chain or branched alkylene group having 2 to 5 carbon atoms, n is any integer from 2 to 5; and 10 a straight-chain or branched alkylene group having 2 to 5 carbon atoms, n is any integer from 2 to 5; and The content of the x2 corresponding chain segment is 22-27 wt% based on the percentage content of the molecular weight of the compound represented by general formula (II), the content of the y2 corresponding chain segment is 21-65 wt%, and the content of the z2 corresponding chain segment is 10-50 wt%.

2. The photocurable resin composition according to claim 1, characterized by The weight ratio of the compound represented by general formula (I) to the compound represented by general formula (II) is (15-35):(15-40).

3. The photocurable resin composition according to claim 1, characterized by The acid value of the compound represented by general formula (I) is 210-310 mgKOH / g; and / or, the acid value of the compound represented by general formula (II) is 170-210 mgKOH / g.

4. The photocurable resin composition according to claim 1, characterized by In the compounds of general formula (I), R1is selected from H or methyl, R2is selected from H or methyl, R3is selected from methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, i-octyl, C 12 straight chain alkyl, C 18 straight chain alkyl, benzyl, glycidyl substituted methylene, hydroxyethyl, hydroxypropyl, hydroxybutyl, -N(CH3)2, or -N(C2H5)2, R4is selected from H or methyl, and z1is 0 or 1, and R4' is selected from H or methyl; and / or, In the compound of general formula (II), R5, R6, R8are independently selected from H or methyl, R7is selected from methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, i-octyl, C 12 straight alkyl, C 18 straight alkyl, benzyl, glycidyl substituted methylene, hydroxyethyl, hydroxypropyl, or hydroxybutyl, R 10 is selected from ethylene, propylene or decylene.

5. The photocurable resin composition according to any one of claims 1 to 3, characterized by, The weight average molecular weight of the compound represented by general formula (I) is 30000-80000, and the molecular weight distribution index is 1.3-2.5; and / or, The weight average molecular weight of the compound represented by general formula (II) is 60000-90000, and the molecular weight distribution index is 1.3-2.

5.

6. The photocurable resin composition according to claim 5, wherein The photo-curable resin composition comprises: an alkali-soluble resin, a photo-polymerization monomer, a photosensitizer and an additive; the alkali-soluble resin comprises compounds represented by general formula (I) and general formula (II):

7. The photocurable resin composition according to claim 6, wherein The photo-polymerization monomer comprises one or more of the following compounds represented by general formula (B1), (B2), (B3), (B4), (B5), (B6): （B1）， wherein m1 and m2 are independently any integer from 1 to 30, n1 and n2 are independently any integer from 0 to 20, m1+m2 is any integer from 2 to 30, n1+n2 is any integer from 0 to 20, the n1 corresponding chain segment is randomly arranged or block arranged with the m1 corresponding chain segment, and the n2 corresponding chain segment is randomly arranged or block arranged with the m2 corresponding chain segment; （B2）， wherein m3 and m4 are independently any integer from 1 to 30, m3+m4 is any integer from 15 to 30, （B3）， wherein a1 and b1 are independently any integer from 0 to 20, the a1 corresponding chain segment is randomly arranged or block arranged with the b1 corresponding chain segment; （B4）， Wherein, a2 and c2 are independently any integer from 0 to 20, b2 is any integer from 1 to 20, a2 + c2 is any integer from 2 to 30, the a2 corresponding segment, the b2 corresponding segment and the c2 corresponding segment are arranged randomly or in blocks; （B5）， Wherein, b3 is any integer from 1 to 20, a3 and c3 are independently any integer from 1 to 20, a3 + c3 is any integer from 2 to 30, b3 is any integer from 2 to 20, the a3 corresponding segment, the b3 corresponding segment and the c3 corresponding segment are arranged randomly or in blocks; （B6）， Wherein, a4 is any integer from 2 to 30, b4 is any integer from 0 to 20, the a4 corresponding segment and the b4 corresponding segment are arranged randomly or in blocks; In the compounds of the general formula (B1), (B2), (B3), (B4), (B5), (B6), R b are each independently selected from H or C1-C4 alkyl, and EO represents ethoxy and PO represents propoxy.

8. The photocurable resin composition according to claim 7, characterized by The photopolymerization monomer further comprises one or more of monofunctional, difunctional or multifunctional (meth)acrylate olefinically unsaturated double bond monomers selected from the group consisting of lauryl (meth)acrylate, stearyl (meth)acrylate, nonyl phenol acrylate, isobornyl acrylate, tetrahydrofurfuryl acrylate, bisphenol A di(meth)acrylate, polyethylene glycol (propylene glycol) di(meth)acrylate, ethoxylated (propoxylated) neopentyl glycol diacrylate, trimethylolpropane tri(meth)acrylate, ethoxylated (propoxylated) trimethylolpropane tri(meth)acrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, polyurethane acrylate.

9. The photocurable resin composition according to claim 6, wherein The photosensitizer comprises a photoinitiator or a hexaarylbiimidazole photoinitiator and a sensitizer represented by general formula (C1) or general formula (C2): (C1), (C2), Among them, R c Selected from H, C1-C6 alkyl, C2-C3 haloalkyl, C1-C3 alkoxy, substituted or unsubstituted aryl, haloaryl, or pyridinyl; R c ’ Selected from C3~C 10 Straight-chain alkylene groups.

10. The photocurable resin composition according to claim 9, characterized by The sensitizer is selected from one or more of the group consisting of aromatic ketone compounds, anthraquinone compounds, coumarin compounds, N-phenyl glycine compounds, anthracene compounds, pyrazoline compounds, amino acid compounds, quinone compounds, phenylethanone compounds, acyl phosphine oxide compounds, benzoin compounds, benzoin ether compounds, dialkyl ketal compounds, thioxanthone compounds, dialkyl aminobenzoate compounds.

11. The photocurable resin composition according to claim 10, characterized in that, The sensitizer is one or more selected from the group consisting of 5-(4- methoxyphenyl)-3-[2-(4-methoxyphenyl)vinyl]-1-phenyl-pyrazoline, 5-phenyl-3- biphenyl-1-phenyl-pyrazoline, 1-phenyl-3-(4-tert-butylstyryl)-5-(4-tert- butylphenyl)-pyrazoline, 1-(4-(benzoxazol-2-yl)phenyl)-3-(4-tert-butylstyryl)-5-(4- tert-butylphenyl)-pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-butylphenyl)- pyrazoline, 1-phenyl-3-(4-biphenyl)-5-(4-tert-octylphenyl)-pyrazoline, N- phenylglycine, N-methyl-N-phenylglycine, N-ethyl-N-phenylglycine, benzophenone, Michler's ketone [4,4'-bis(dimethylamino)benzophenone], 4,4'-bis(diethylamino)benzophenone, and 4-methoxy-4'-dimethylaminobenzophenone.

12. The photocurable resin composition according to claim 11, characterized by The ratio of the total weight of the compound represented by the general formula (C1) and the compound represented by the general formula (C2) and the sensitizer to the sum of the weights of the alkali-soluble resin and the photopolymerization monomer is (0.3-2):

100.

13. The photocurable resin composition according to claim 1, wherein The additive is one or more selected from the group consisting of a color former, a color developer, a plasticizer, a photothermal stabilizer, an adhesion promoter, a leveling agent, an antifoaming agent, and a polymerization inhibitor.

14. Use of the photocuring resin composition according to any one of claims 1 to 13 in the field of photocuring.

15. A photosensitive dry film resist layer stack, characterized by, The photosensitive dry film resist layer stack includes a support layer and a resist layer, and the resist layer is prepared from the photocuring resin composition according to any one of claims 1 to 13. The photosensitive dry film resist layer stack includes a support layer and a resist layer, and the resist layer is prepared from the photocuring resin composition according to any one of claims 1 to 13.

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