LDI solder resist ink and preparation method thereof

Abstract

The invention provides LDI solder resist ink and a preparation method thereof, and belongs to the technical field of solder resist ink, raw materials of the LDI solder resist ink comprise the following components: carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, an inorganic filler, a photoinitiator and an auxiliary agent, the carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin is prepared by the following steps: adding carboxyl-polycaprolactone acrylate and acrylic acid into an epoxy resin modified solution, uniformly dispersing by a certain preparation method, grinding and the like. According to the LDI solder resist ink obtained by the invention, the photosensitivity can be improved, and the problems of long exposure time and low curing speed caused by mismatching of an LDI exposure machine and ink are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of solder resist ink, and in particular to an LDI solder resist ink and a preparation method thereof. Background Art

[0002] Solder resist ink is a special material used in the welding process. It is mainly used to form a protective film on the circuit board to prevent the non-solder point area of ​​the circuit board from contacting the solder during the welding process, thereby avoiding problems such as short circuits. Solder resist ink usually needs to have good electrical insulation and physical and mechanical properties, and be able to withstand high temperatures.

[0003] At present, LDI circuit ink and LDI equipment are very mature, but LDI solder mask equipment and supporting LDI are not yet mature and are still in the research and development stage. The main advantages of LDI equipment are: (1) Traditional exposure is to transfer the image to the PCB photosensitive film by irradiating the film with a mercury lamp, while LDI uses laser scanning to directly image the circuit image on the PCB, without the need for film, saving more film and labor and time for drawing film; (2) LDI images are more detailed and can be made into 2mil solder mask; (3) LDI can realize automatic exposure, reducing the impact of uncontrollable factors such as human factors on production quality; (4) LDI has better resolution ability than traditional machines and higher stability. According to the dry film, the maximum resolution can be 1.5 / 1.5mil, while traditional exposure machines generally resolve to 2.5 / 2.5mil.

[0004] The main problem of LDI machine: it is not compatible with the existing ink, resulting in long exposure time, waste of manpower and material resources; LDI is superior to traditional exposure in both obvious and invisible benefits, and circuit boards will become more and more sophisticated in the future. Therefore, LDI ink has become a trend and the development trend of liquid photosensitive solder mask ink in the future.

[0005] The present invention adds acrylic acid and carboxyl-polycaprolactone acrylate to the epoxy resin modified solution to improve the photosensitivity, solve the problems of LDI exposure machine not matching with ink, resulting in long exposure time, slow curing speed, excessive undercut, etc., and achieve the purpose of LDI rapid curing. Summary of the invention

[0006] In view of this, the present invention provides an LDI solder resist ink and a preparation method thereof, which can improve photosensitivity and solve the problem that the LDI exposure machine is not matched with the ink, resulting in a long exposure time and a slow curing speed.

[0007] The specific scheme of the present invention is as follows: an LDI solder resist ink, the raw materials of which include the following components: carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin, inorganic filler, photoinitiator and auxiliary agent; The carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin is obtained by adding acrylic acid into the epoxy resin modified solution and then compounding the carboxyl-polycaprolactone acrylate.

[0008] The above-mentioned carboxyl-polycaprolactone acrylate is abbreviated as PCL-COOH, which is prepared by polymerizing caprolactone (ε-caprolactone) monomers and introducing carboxyl functional groups into the polymer chain.

[0009] The present invention adds acrylic acid to the epoxy resin modified solution, and then compound carboxyl-polycaprolactone acrylate to obtain carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin. By utilizing the double bond contained in carboxyl-polycaprolactone acrylate, the adhesion of the metal material can be increased, so that it has high sensitivity performance, thereby improving the exposure efficiency, and solving the problems of high exposure energy, long exposure time, slow photocuring speed, and band mismatch of the silk screen ink. At the same time, carboxyl-polycaprolactone acrylate contains carboxyl, and PCL-COOH has a longer molecular chain and higher molecular activity than acrylic acid. When epoxy is combined, the molecular chain is longer, and the molecular chain of epoxy resin is significantly lengthened, which can improve the flexibility of the ink, make the product more resistant to chemical erosion and heat shock, and the carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin itself contains multiple carboxyls, which can improve the overall compatibility, thereby achieving the obvious growth of the epoxy resin molecular chain while enhancing the overall compatibility.

[0010] It is combined with other inorganic fillers, photoinitiators and additives to achieve high sensitivity to improve exposure efficiency, shorten exposure time, and fast curing speed, which can match the needs of LDI exposure machines and meet the needs of more high-demand exposure machine inks. It can achieve better resolution, fast data switching, automatic exposure, and reduce the impact of human factors.

[0011] Preferably, the raw materials of the carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin include the following components: epoxy resin, acrylic acid, carboxyl-polycaprolactone acrylate, catalyst, inhibitor and tetrahydrophthalic anhydride, GMA 2-8 parts, and diluent 20-43 parts.

[0012] Preferably, the raw materials of the carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin include the following components in parts by mass: Epoxy resin 25-40 parts; acrylic acid 5-15 parts; carboxyl-polycaprolactone acrylate 2-15%; catalyst 0.1-10%; inhibitor 0.1-10%; tetrahydrophthalic anhydride 10%-30%.

[0013] Preferably, the carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin is obtained by the following preparation method: Epoxy resin, diluent, polymerization inhibitor and catalyst are added into a reaction kettle, dispersed and stirred, acrylic acid and carboxyl-polycaprolactone acrylate are added, the temperature is raised to react, diluent and tetrahydrophthalic anhydride are added and the temperature is lowered, GMA is added, the temperature is kept, dispersed and stirred, and the temperature is lowered to obtain carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin.

[0014] Glycidyl methacrylate is an ester compound with the molecular formula C7H 10 O3, also known as 2,3-epoxypropyl methacrylate, abbreviated as GMA. The epoxy resin is modified by first adding epoxy resin, diluent, inhibitor and catalyst, and then adding acrylic acid and carboxyl-polycaprolactone acrylate to react to obtain carboxyl-polycaprolactone acrylate epoxy resin. Finally, tetrahydrophthalic anhydride is added, and GMA is added after cooling to avoid self-polymerization of GMA due to high temperature. Finally, GMA is also ring-opened and connected to carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin, further increasing the double bond content of the resin, and finally mixed to obtain carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin.

[0015] Preferably, in the preparation method, epoxy resin and diluent are added to a reaction kettle, first heated to 90-110°C, dispersed for 1H after the temperature stabilizes, then added with inhibitor and catalyst, stirred for 20-30min until completely dissolved, added with acrylic acid and carboxyl-polycaprolactone acrylate, then heated to 115-125°C for reaction, tested the acid value every hour, and when the acid value is less than 6 mgKOH / g, added with diluent and tetrahydrophthalic anhydride and the temperature is reduced to 95-100°C, and when the acid value reaches 45-50, GMA is added, and the temperature is kept at 90-100°C, dispersed and stirred for 2-4 hours, and then cooled to room temperature to obtain carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin. Preferably, the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, linear novolac epoxy resin and o-cresol novolac epoxy resin; The polymerization inhibitor is one or more of p-benzoquinone, hydroquinone, p-hydroxyanisole, 2,5-di-tert-butylhydroquinone and 2-tert-butylhydroquinone; The catalyst is one or more of hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid and metal salts.

[0016] Preferably, the raw materials also include 1-15 parts of acrylic acid ester and high temperature curing resin, and the mass fractions of each component are as follows: 10-50 parts of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin; 20-60 parts of inorganic filler; 0.1-10 parts of photoinitiator; 0.1-3 parts of auxiliary agent; 1-30 parts of acrylate; 1-15 parts of high temperature curing resin and 0.5-3 parts of melamine.

[0017] Preferably, the photoinitiator is a free radical initiator, and the free radical initiator is one or more combinations of bis-2,6-difluoro-3-pyrrolephenyl titanocene, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl p-N,N-dimethylaminobenzoate, tetraethyl Michler's ketone, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone and isopropylthioxanthone or 2,4-diethylthioxanthone; The acrylate is one or more of monofunctional, trifunctional, hexafunctional and multifunctional acrylates; preferably one or more of DPHA, TMPTA, 3EO-TMPTA and HEMA; The high temperature curing resin is one or more of epoxy resin, multifunctional high temperature resistant epoxy resin, acrylate and triglycidyl isocyanurate; The inorganic filler is mainly one or more combinations of barium sulfate, silicon micropowder and talcum powder. The auxiliary agent is KS-66 and / or BYK-405.

[0018] The inorganic filler is preferably silicon micropowder, which has good insulation, high temperature resistance, acid and alkali resistance, and high hardness; the multifunctional high temperature resistant epoxy resin can be such as trifunctional epoxy resin, which has low viscosity, high reaction speed, high temperature resistance, and better chemical resistance; acrylates can be such as TM, DPHA and other reactive monomers that participate in photocuring reactions.

[0019] The present invention also provides a method for preparing an LDI solder resist ink, comprising the following steps: S1, mixing carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin, acrylic acid, photoinitiator, auxiliary agent and inorganic filler, uniformly dispersing and grinding to obtain agent A; S2, mixing the high temperature curing resin, acrylate and catalyst, uniformly dispersing and grinding to obtain agent B; S3, mixing the agent A and the agent B prepared in the above steps, and dispersing them evenly to finally obtain LDI solder resist ink.

[0020] Preferably, in step S1, carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin, acrylic acid, photoinitiator, auxiliary agent and inorganic filler are added to the reaction kettle in sequence for mixing, uniformly dispersed for 30-40 minutes, and then ground by a hydraulic three-roll grinder for 3-4 times to a fineness of less than 10 μm. After uniform dispersion, the viscosity is adjusted to between 200 dpa.s and 250 dpa.s, and filtered to obtain agent A; In the step S2, the high temperature curing resin, acrylic acid ester and catalyst are added to another reaction kettle for mixing, uniformly dispersed for 30-40 minutes, and then ground by a hydraulic three-roll grinder for 1-3 times until the fineness reaches less than 10 μm. After uniform dispersion, the viscosity is adjusted to 200 dpa.s-250 dpa.s, filtered, and the B agent is obtained.

[0021] The above technical solution of the present invention includes at least the following beneficial effects: The present invention improves exposure efficiency by adding carboxyl-polycaprolactone acrylate and utilizing the high sensitivity of carboxyl-polycaprolactone acrylate, thereby solving the problems of high exposure energy, long exposure time, slow photocuring speed, and band mismatch of screen printing ink. The present invention obtains carboxyl-polycaprolactone acrylate as the main resin by adding acrylic acid to the epoxy resin modified solution and then compounding carboxyl-polycaprolactone acrylate, thereby significantly increasing the molecular chain of the epoxy resin, thereby improving the flexibility of the ink, and making it more resistant to chemical erosion and heat shock. In addition, the carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin itself contains multiple carboxyl groups, which can also improve the overall compatibility, thereby achieving significant growth of the epoxy resin molecular chain while enhancing the overall compatibility. DETAILED DESCRIPTION In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described in combination with the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0022] Example 1 Preparation of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, each raw material component is calculated by mass: 40 parts of o-cresol epoxy resin and 10 parts of diluent DBE are added to the reactor, the temperature is raised to 95°C, and dispersed for 1 hour after the temperature is stable, and then 0.3 parts of HQ (hydroquinone) and 0.5 parts of TPP (triphenyl phosphate) are added, and stirred for 30 minutes until completely dissolved, and then 5 parts of acrylic acid and 15 parts of carboxyl-polycaprolactone acrylate are added, and the temperature is raised to 120°C for reaction. When the acid value is less than 6 mgKOH / g, 27 parts of DBE and 17.5 parts of tetrahydrophthalic anhydride are added, and the temperature is lowered to 98°C. When the acid value reaches 50, 2 parts of GMA are added, and the temperature is kept at 95°C. After dispersion and stirring for 2 hours, the temperature is lowered to obtain carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin.

[0023] Preparation of LDI solder resist ink, each raw material component is calculated by weight: 10 parts of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, 6 parts of acrylate, 1 part of 907 (2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone), 1 part of ITX (isopropylthioxanthone), 1 part of EDB (ethyl p-N,N-dimethylaminobenzoate), 1 part of 784 (bis-2,6-difluoro-3-pyrrolophenyl titanocene), 1 part of KS-66, 1 part of BYK-405, 6 parts of DBE and 43 parts of barium sulfate are added in sequence, dispersed for 30 minutes until uniformly dispersed, and then ground by a hydraulic three-roll mill for 3 times to a fineness of less than 10 μm. After uniform dispersion, the viscosity is adjusted to 200 dpa.s, and the coarse powder particles are removed by filtration to obtain agent A; 10 parts of triglycidyl isocyanurate (TGIC), 1 part of diluent DBE, 4 parts of acrylate and 0.5 parts of melamine were uniformly dispersed for 30 minutes, and then ground twice with a three-roll mill until the fineness reached less than 10 μm. After uniform dispersion, the viscosity was adjusted to 200 dpa.s, and the coarse powder particles were removed by filtration to obtain Agent B; The LDI solder resist ink can be obtained by uniformly dispersing the above-obtained agent A and agent B.

[0024] Example 2 Preparation of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, each raw material is calculated by mass percentage: 30 parts of o-cresol epoxy resin and 10 parts of DBE are added to a reactor, heated to 95°C, dispersed for 1 hour after the temperature stabilizes, and then 0.3 parts of HQ and 0.2 parts of TPP are added, stirred for 30 minutes until completely dissolved, and then 9.6 parts of acrylic acid and 2.4 parts of carboxyl-polycaprolactone acrylate epoxy resin are added, and the temperature is raised to 120°C for reaction. When the acid value is less than 6 mgKOH / g, 27 parts of DBE and 17.5 parts of tetrahydrophthalic anhydride are added, and the temperature is lowered to 98°C. When the acid value reaches 50, 3 parts of GMA are added, and the temperature is kept at 95°C. After dispersion and stirring for 2 hours, the temperature is lowered to obtain carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin.

[0025] Preparation of LDI solder resist ink, each raw material is calculated by mass percentage: 25 parts of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, 6 parts of acrylate, 3 parts of 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone, 1 part of EDB, 2 parts of KS-66, 1 part of BYK-405, 6 parts of DBE and 43 parts of silicon powder are added in sequence, dispersed for 30 minutes until uniformly dispersed, and then ground by a hydraulic three-roll mill for 3 times to a fineness of less than 10μm. After uniform dispersion, the viscosity is adjusted to 250dpa.s, and the coarser powder particles are removed by filtration to obtain agent A; 10 parts of high temperature curing resin, 1 part of EDB and 1 part of melamine were uniformly dispersed for 15 minutes, and then ground twice by a three-roll mill to a fineness of less than 10 μm. After uniform dispersion, the viscosity was adjusted to 200 dpa.s-250 dpa.s, and the coarse powder particles were removed by filtration to obtain Agent B; The LDI solder resist ink can be obtained by uniformly dispersing the above-obtained agent A and agent B.

[0026] Example 3 Carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin was prepared. The raw material components were calculated by weight: 25 parts of bisphenol A epoxy resin and 6 parts of DBE were added to a reactor, the temperature was raised to 90°C, and the mixture was dispersed for 1 hour after the temperature stabilized. Then, 0.1 parts of p-benzoquinone and 0.1 parts of TPP were added and stirred for 20 minutes until they were completely dissolved. Then, 15 parts of acrylic acid and 2 parts of carboxyl-polycaprolactone acrylate were added and the temperature was raised to 125°C for reaction. When the acid value was less than 6 mgKOH / g, 14 parts of DBE and 30 parts of tetrahydrophthalic anhydride were added and the temperature was lowered to 98°C. When the acid value reached 50, 6 parts of GMA were added and the temperature was kept at 90°C. After dispersion and stirring for 2 hours, the temperature was lowered to obtain carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin.

[0027] Preparation of LDI solder resist ink, each raw material component is calculated by weight; 50 parts of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, 25 parts of acrylic acid, 3 parts of 907, 2 parts of ITX, 3 parts of KS-66, 10 parts of DBE and 60 parts of talc are added in sequence, dispersed for 40 minutes until uniformly dispersed, and then ground by a hydraulic three-roll mill for 4 times to a fineness of less than 10 μm. After uniform dispersion, the viscosity is adjusted to 250 dpa.s, and the coarser powder particles are removed by filtration to obtain agent A; 15 parts of high temperature curing resin (TGIC), 5 parts of diluent DBE, 5 parts of acrylate and 3 parts of melamine were uniformly dispersed for 40 minutes, and then ground by a three-roll mill for 3 times until the fineness reached less than 10 μm. After uniform dispersion, the viscosity was adjusted to 250 dpa.s, and the coarse powder particles were removed by filtration to obtain Agent B; The LDI solder resist ink can be obtained by uniformly dispersing the above-obtained agent A and agent B.

[0028] Example 4 Carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin was prepared. The raw material components were calculated by weight: 20 parts of bisphenol F epoxy resin, 20 parts of linear phenolic epoxy resin and 15 parts of DBE were added to a reactor, the temperature was raised to 110°C, and the mixture was dispersed for 1 hour after the temperature was stable. Then, 5 parts of 2,5-di-tert-butylhydroquinone and 6 parts of TPP were added and stirred for 30 minutes until completely dissolved. Then, 12 parts of acrylic acid and 11 carboxyl-polycaprolactone acrylate were added and the temperature was raised to 115°C for reaction. When the acid value was less than 6 mgKOH / g, 28 parts of DBE and 10 parts of tetrahydrophthalic anhydride were added, the temperature was lowered to 100°C, and when the acid value reached 45, 8 parts of GMA were added, the temperature was kept at 100°C, and the mixture was dispersed and stirred for 4 hours and then cooled to obtain carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin.

[0029] Preparation of LDI solder resist ink, each raw material component is calculated by weight; 10 parts of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, 3 parts of acrylate, 0.1 parts of photoinitiator 784, 0.1 parts of auxiliary agent BYK-405, 5 parts of DBE and 20 parts of silicon micropowder are added in sequence, dispersed for 30 minutes until uniformly dispersed, and then ground twice by a hydraulic three-roll mill to a fineness of less than 10 μm. After uniform dispersion, the viscosity is adjusted to 200 dpa.s, and the coarser powder particles are removed by filtration to obtain agent A; 2 parts of triglycidyl isocyanurate, 2 parts of epoxy resin linear phenolic epoxy resin, 1 part of diluent DBE, 2 parts of acrylate and 1 part of melamine were uniformly dispersed for 15 minutes, and then ground once with a three-roll mill until the fineness reached less than 10 μm. After uniform dispersion, the viscosity was adjusted to 200 dpa.s, and the coarse powder particles were removed by filtration to obtain Agent B; The LDI solder resist ink can be obtained by uniformly dispersing the above-obtained agent A and agent B.

[0030] Example 5 Carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin was prepared. The raw material components were calculated by weight: 30 parts of o-cresol epoxy resin and 10 parts of DBE were added to a reactor, the temperature was raised to 95°C, and the mixture was dispersed for 1 hour after the temperature was stabilized. Then, 0.5 parts of p-hydroxyanisole, 1 part of 2-tert-butylhydroquinone and 3 parts of TPP were added, and the mixture was stirred for 30 minutes until it was completely dissolved. Then, 10 parts of acrylic acid and 9 parts of carboxyl-polycaprolactone acrylate were added, and the temperature was raised to 125°C for reaction. When the acid value was less than 6 mgKOH / g, 25 parts of DBE and 17.5 parts of tetrahydrophthalic anhydride were added, and the temperature was lowered to 100°C. When the acid value reached 50, 3 parts of GMA were added, the temperature was kept at 100°C, and the mixture was dispersed and stirred for 2 hours and then cooled to obtain carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin.

[0031] Preparation of LDI solder resist ink, each raw material component is calculated by mass; 25 parts of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, 6 parts of acrylate, 1 part of tetraethyl Michler's ketone, 2 parts of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2 parts of auxiliary agent BYK-405, 6 parts of DBE and 30 parts of silicon micropowder are added in sequence, dispersed for 30 minutes until uniformly dispersed, and then ground by a hydraulic three-roll mill for 3 times to a fineness of less than 10 μm. After uniform dispersion, the viscosity is adjusted to 220 dpa.s, and the coarser powder particles are removed by filtration to obtain agent A; 10 parts of TGIC, 2 parts of diluent DBE, 2 parts of acrylate and 1 part of melamine were uniformly dispersed for 30 minutes, and then ground twice by a three-roll mill until the fineness reached less than 10 μm. After uniform dispersion, the viscosity was adjusted to 230 dpa.s, and the coarse powder particles were removed by filtration to obtain Agent B; The LDI solder resist ink can be obtained by uniformly dispersing the above-obtained agent A and agent B.

[0032] Comparative Example 1 Compared with Example 2, the only difference is that carboxyl-polycaprolactone acrylate is not added, and other components and preparation steps are consistent with Example 2 to prepare LDI solder resist ink.

[0033] Comparative Example 2 Compared with Example 2, the only difference is that acrylic acid is not added, and other components and preparation steps are consistent with Example 2 to prepare LDI solder resist ink.

[0034] Performance testing A 1.5-ounce copper thick PCB circuit board was used. After spraying and grinding, the holes were plugged with aluminum sheets and exposed with an LDI machine. The upper and lower developing pressures were both 25 psi for 60 seconds. The segmented curing conditions were: 75°C*30min+90°C*30min+120°C*30min+150°C*120min. The following performance tests were performed on the LDI solder mask ink products obtained in Examples 1-5 and Comparative Examples 1-2, respectively.

[0035] The sensitivity scale (grid) test was carried out under the same exposure energy, and the results are shown in Table 1 below.

[0036] Table 1

[0037] It can be seen from Table 1 that the sensitivity scale numbers of Examples 1-5 can be maintained at a high level at the same exposure energy, and the sensitivity is high; while the sensitivity scale numbers of Comparative Examples 1-2 are obviously poor at the same exposure energy.

[0038] Under the same sensitivity scale of 8 grids, the exposure energy (mj / cm 2 ) test, and the results are shown in Table 2 below.

[0039] Table 2

[0040] As shown in Table 2, under the same sensitivity scale, the exposure energy required for Examples 1-5 is significantly lower than that for Comparative Example 1-2, with a difference of 300 mj / cm 2 The above indicates that the LDI solder resist ink obtained by the present invention has low exposure energy and excellent performance.

[0041] At the same exposure energy (mj / cm 2 ) conditions, the undercut (um) test was carried out and the results are shown in Table 3 below.

[0042] Table 3

[0043] It can be seen from Table 3 that under the same exposure energy, the side erosion degree of Examples 1-5 is significantly lower than that of Comparative Examples 1-2. The product obtained in this embodiment can avoid excessive side erosion and has excellent performance.

[0044] Under the condition of the same sensitivity scale of 8 grids, undercut (um) test was carried out, and the results are shown in Table 4 below.

[0045] Table 4

[0046] It can be seen from Table 4 that, under the same sensitivity scale, the side erosion degree of Examples 1-5 is also significantly lower than that of Comparative Examples 1-2, indicating that the product obtained in this embodiment can reduce the side erosion under the same sensitivity scale.

[0047] The time (min) that can be achieved by testing the products of each embodiment and comparative example at the pre-bake development limit of 75° C., and the results are shown in Table 5 below.

[0048] Table 5

[0049] It can be seen from Table 5 that under the pre-baking limit of 75°C, the products of Examples 1-5 can reach 80 min, while the products of Comparative Examples 1-2 cannot reach 80 min, and even Comparative Example 1 cannot reach 70 min.

[0050] The products of each embodiment and comparative example were pre-baked at 75° C. for 45 minutes and then placed in a storage test. The results are shown in Table 6 below.

[0051] Table 6

[0052] As can be seen from Table 6, in the pre-baking test at 75°C for 45 minutes, the products of Examples 1-5 can reach 36 hours, while the products obtained in Comparative Examples 1-2 cannot even reach 24 hours, indicating that the LDI solder mask ink obtained by the combination of carboxyl-polycaprolactone acrylate and acrylic acid components of the present invention has excellent performance.

[0053] The products of each embodiment and comparative example were tested for heat shock resistance three times under the conditions of tin temperature of 288° C. and tin immersion for 10 seconds. The results are shown in Table 7 below.

[0054] Table 7

[0055] It can be seen from Table 7 that the products of Examples 1-5 can withstand three heat shocks, while the product obtained in Comparative Example 1 cannot withstand three heat shocks, indicating that the use of carboxyl-polycaprolactone acrylate can also play an important role in improving the heat shock resistance of LDI solder mask ink.

[0056] In summary, the product obtained by the embodiment of the present invention has excellent performance in reducing exposure energy, improving sensitivity, reducing side erosion, and improving development limit and parking tolerance, etc., which shows that the LDI ink of the present invention has good comprehensive performance and can be promoted and applied.

[0057] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A LDI solder resist ink, characterized in that: The raw materials include the following components: carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin, inorganic filler, photoinitiator and auxiliary agent.

2. The LDI solder resist ink according to claim 1, characterized in that: The raw materials of the carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin include the following components: epoxy resin, acrylic acid, carboxyl-polycaprolactone acrylate, catalyst, polymerization inhibitor, tetrahydrophthalic anhydride, GMA and diluent.

3. The LDI solder resist ink according to claim 2, characterized in that: The raw materials of the carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin include the following components in parts by mass: Epoxy resin 25-40 parts; acrylic acid 5-15 parts; carboxyl-polycaprolactone acrylate 2-15 parts; catalyst 0.1-10 parts; inhibitor 0.1-10 parts; tetrahydrophthalic anhydride 10-30 parts, GMA 2-8 parts, diluent 20-43 parts.

4. The LDI solder resist ink according to claim 3, characterized in that: The carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin is obtained by the following preparation method: Epoxy resin, diluent, polymerization inhibitor and catalyst are added into a reaction kettle, dispersed and stirred, acrylic acid and carboxyl-polycaprolactone acrylate are added, the temperature is raised to react, diluent and tetrahydrophthalic anhydride are added and the temperature is lowered, GMA is added, the temperature is kept, dispersed and stirred, and the temperature is lowered to obtain carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin.

5. The LDI solder resist ink according to claim 4, characterized in that: In the preparation method: Add epoxy resin and diluent into a reactor, heat it to 90-110°C, disperse it for 1 hour after the temperature stabilizes, then add inhibitor and catalyst, stir for 20-30 minutes until it is completely dissolved, add acrylic acid and carboxyl-polycaprolactone acrylate, heat it to 115-125°C for reaction, test the acid value every hour, add diluent and tetrahydrophthalic anhydride when the acid value is less than 6 mg KOH / g, and lower the temperature to 95-100°C, add GMA when the acid value reaches 45-50, keep warm at 90-100°C, disperse and stir for 2-4 hours, and then lower it to room temperature to obtain carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin.

6. The LDI solder resist ink according to claim 2, characterized in that: The epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, linear phenolic epoxy resin and o-cresol epoxy resin; The polymerization inhibitor is one or more of p-benzoquinone, hydroquinone, p-hydroxyanisole, 2,5-di-tert-butylhydroquinone and 2-tert-butylhydroquinone; The catalyst is one or more of hydrochloride, nitrate, phosphate, sulfate and metal salts, the phosphate is triphenyl phosphate TPP, and the diluent is DBE.

7. The LDI solder resist ink according to claim 1, characterized in that: The raw materials also include 1-15 parts of acrylic acid ester and high temperature curing resin, and the mass parts of each component are as follows: 10-50 parts of carboxylic acid modified carboxyl-polycaprolactone acrylate epoxy resin; 20-60 parts of inorganic filler; 0.1-10 parts of photoinitiator; 0.1-3 parts of auxiliary agent; 1-30 parts of acrylate; 1-15 parts of high temperature curing resin, 0.5-3 parts of melamine, and 7-15 parts of diluent.

8. The LDI solder resist ink according to claim 7, characterized in that: The photoinitiator is a free radical initiator, and the free radical initiator is one or more combinations of bis-2,6-difluoro-3-pyrrolephenyl titanocene, 2-methyl-2-(4-morpholinyl)-1-[4-(methylthio)phenyl]-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, ethyl p-N,N-dimethylaminobenzoate, tetraethyl Michler's ketone, 2-dimethylamino-2-benzyl-1-[4-(4-morpholinyl)phenyl]-1-butanone and isopropylthioxanthone or 2,4-diethylthioxanthone; The acrylate is one or more of monofunctional, trifunctional, hexafunctional and multifunctional acrylates; preferably one or more of DPHA, TMPTA, 3EO-TMPTA and HEMA; The high temperature curing resin is one or more of epoxy resin, multifunctional high temperature resistant epoxy resin, acrylate and triglycidyl isocyanurate; The inorganic filler is mainly one or more combinations of barium sulfate, silicon powder and talc; The additives are KS-66 and / or BYK-405.

9. A method for preparing the LDI solder resist ink according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, mixing carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin, acrylic acid, photoinitiator, auxiliary agent and inorganic filler, uniformly dispersing and grinding to obtain agent A; S2, mixing the high temperature curing resin, acrylate and catalyst, uniformly dispersing and grinding to obtain agent B; S3, mixing the agent A and the agent B prepared in the above steps, and dispersing them evenly to finally obtain LDI solder resist ink.

10. The method for preparing a LDI solder resist ink according to claim 9, characterized in that: In the step S1, carboxylic acid-modified carboxyl-polycaprolactone acrylate epoxy resin, acrylic acid, photoinitiator, auxiliary agent and inorganic filler are added to the reaction kettle in sequence for mixing, uniformly dispersed for 30-40 minutes, and then ground by a hydraulic three-roll grinder for 2-4 times to a fineness of less than 10 μm. After uniform dispersion, the viscosity is adjusted to between 200 dpa.s and 250 dpa.s, and filtered to obtain agent A; In the step S2, the high temperature curing resin, acrylic acid ester and catalyst are added to another reaction kettle for mixing, uniformly dispersed for 30-40 minutes, and then ground by a hydraulic three-roll grinder for 1-3 times until the fineness reaches less than 10 μm. After uniform dispersion, the viscosity is adjusted to 200 dpa.s-250 dpa.s, filtered, and the B agent is obtained.

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