Braille printing ink and preparation method and application of matched primer

Abstract

The invention discloses Braille ink-jet printing ink and a preparation method and application of a matched primer. The ink contains 15-50 parts of a photocurable prepolymer, 15-75 parts of a reactive diluent, 5-20 parts of a photoinitiator and 1-10 parts of an auxiliary agent, and the matched primer contains 10-80 parts of fluorine-containing polyurethane acrylate, 10-80 parts of acrylic acid modified chlorinated polypropylene and 5-20 parts of a photoinitiator. The preparation method comprises the following steps: 1) spraying a matched primer to a to-be-sprayed area of a polypropylene base material, and heating and curing to obtain a partially cured primer; (2) ink is printed on the base coat in an ink-jet mode according to a set pattern, and single-layer protruding braille alphabets are obtained after light curing; and (3) carrying out stacking ink-jet printing on the single-layer convex braille points for multiple times to obtain braille points with a set height. According to the method, effective attachment of the ink and the base material is ensured, meanwhile, the ink has a high height-diameter ratio after being cured on the base coat, the ink jet stacking frequency needed for achieving the set braille point height is reduced, and the stacking efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of braille printing, and is a method for preparing braille inkjet printing ink and a matching primer liquid, as well as a method for preparing braille printed products applied to a polypropylene substrate. Background Art

[0002] Braille, also known as dot characters or embossed characters, is a text designed specifically for the blind and perceived by touch. According to national standards, Braille must have a certain height so that the blind can touch and identify it. The raised points of Braille are generally hemispherical or parabolic to ensure the comfort of the blind when touching the Braille. Given that Braille is often touched, this requires that Braille must have good adhesion to the substrate to prevent the Braille from falling off during use. Traditional Braille products are made by engraving or stamping methods, which have the disadvantages of low production efficiency, high cost, and easy falling off and wear of Braille dots. In recent years, with the continuous maturity of high-efficiency, low-cost, and high-performance inkjet printing technology, more and more Braille products are made using inkjet printing.

[0003] The invention of Braille has greatly facilitated the lives of the blind. In order to further facilitate the travel and life of the blind, my country has built a large number of barrier-free facilities. In recent years, as people's understanding of "barrier-free" has deepened, many public facilities such as subway handrails and bus stops have also been equipped with metal Braille.

[0004] Plastic banknotes are a type of banknote made of plastic as the main material. They were first issued by Australia. Compared with traditional paper banknotes, they have the characteristics of no fiber, no pores, no moisture absorption, small deformation, high temperature resistance, no odor, not easy to be contaminated with bacteria, no adhesion, easy to decontaminate and disinfect, and easy to recycle. They are the next generation of banknotes that all countries are striving to develop. my country has issued plastic commemorative banknotes, which are made of polypropylene as the main raw material and a multi-layer film prepared by biaxial stretching technology, referred to as BOPP film.

[0005] Polypropylene has chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties and good high-wear resistance processing properties. It is a non-polar material and lacks a structure that can chemically bond with ink. It is difficult for ink to form effective adhesion on the surface. How to print patterns with a certain height on the surface of polypropylene and achieve effective adhesion has always been a difficulty in current research.

[0006] The Chinese patent document with publication number CN108909230A discloses an inkjet printing medium of weak solvent ink and a preparation method thereof, and proposes a method to solve the problem that liquid jet ink cannot be properly attached to BOPP film by inkjet. However, the weak solvent ink prepared in the patent contains a certain amount of solvent, and the inkjet cannot be quickly cured, which is not conducive to large-scale production.

[0007] The Chinese patent with publication number CN110079155A discloses a high-fastness water-based dye ink and a preparation method thereof, wherein the prepared ink has a certain adhesion on a polypropylene film. However, the ink in the patent is a water-based ink and cannot be cured quickly.

[0008] The Chinese patent with publication number CN102806778A discloses a Braille inkjet printing device and printing method, which uses multiple printing modules to print multiple layers of Braille printing data respectively, and superimposes each layer on the same position of the printing medium to obtain Braille of the required height. The printing device required by this patent is relatively complex, and the precision required for controlling the superimposed printing of each layer is relatively high, and the number of stacked printings is relatively large.

[0009] In summary, the existing technology for preparing Braille has problems such as complex production equipment, low inkjet stacking efficiency, and slow ink curing speed, and the preparation of Braille on a polypropylene substrate also has the problem of low adhesion. Summary of the invention

[0010] The purpose of the present invention is to solve the problems of low height-to-diameter ratio of braille raised points, low stacking efficiency and difficulty in ink adhesion on polypropylene materials in braille inkjet printing. The braille printed product prepared by the method of the present invention requires fewer stacking printing times and high preparation efficiency, and reduces production costs, provided that the height of the predetermined braille raised points is reached. The printed braille raised points have good adhesion on the polypropylene substrate, and the primer can be prepared in advance on the polypropylene substrate without affecting the subsequent inkjet printing efficiency.

[0011] The present invention achieves the above-mentioned purpose by the following measures: a Braille printing ink and a matching primer

[0012] The Braille inkjet printing ink is composed of 5-50 parts of a photocurable prepolymer, 15-75 parts of a reactive diluent, 5-20 parts of a photoinitiator, and 1-10 parts of an auxiliary agent;

[0013] The matching primer is composed of 10-80 parts of fluorine-containing polyurethane acrylate, 10-80 parts of acrylic acid-modified chlorinated polypropylene, and 5-20 parts of photoinitiator.

[0014] The present invention also provides the method of applying the braille printing ink and the matching primer on a polypropylene substrate to prepare a braille print.

[0015] The present invention also provides a method for preparing the Braille printed matter, the method comprising the following steps:

[0016] 1) spraying the matching primer onto the area to be sprayed on the polypropylene substrate, heating and curing, and obtaining a partially cured primer;

[0017] 2) printing the braille printing ink on the primer in a predetermined pattern, and obtaining a single layer of raised braille after light curing;

[0018] The single layer of raised Braille dots is printed multiple times with inkjet printing to obtain Braille dots of a given height.

[0019] The following are further optimizations and / or improvements to the above measures:

[0020] The photocurable prepolymer is one or more of polyurethane acrylate, polyester acrylate, epoxy acrylate, and hyperbranched polyurethane acrylate, and the functionality of the resin is 6-12.

[0021] The above-mentioned active diluent is a mixture of several of diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, acrylate (5-cycloethyl-2-methyl-1,4-dioxolane) 2-methyl ester, 2-phenoxyethyl acrylate, and alkane carboxylic acid epoxy ester modified acrylic acid.

[0022] The photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone.

[0023] The above-mentioned additives are defoaming agents, dispersants, and inhibitors, and the brands of the additives are several of Foamex-810, Foamex-N, Airex-920, BYKP-105, Disperbyk-111, Rad-2100, Rad-2200N, Rad-2700, and p-hydroxyanisole.

[0024] The above-mentioned fluorine-containing polyurethane acrylate is a commercially available product, and examples thereof include SD-1338B (manufactured by Songda New Materials, silicon-fluorinated polyurethane acrylate resin), SF-009 (Mo Neng Chemical, organic fluorine-modified polyurethane acrylate), and the like.

[0025] The acrylic acid-modified chlorinated polypropylene is a commercially available product, and the brands include PP-801 (Changzhou Sisai, chlorinated polypropylene modified acrylic resin), PP-807 (Changzhou Sisai, chlorinated polypropylene modified acrylic resin), and the like.

[0026] The primer liquid is prepared by physically mixing fluorinated polyurethane acrylate, acrylic acid-modified chlorinated polypropylene and a photoinitiator, and standing to defoam. The primer liquid is sprayed onto the area to be sprayed on the polypropylene substrate, and is heated and cured to prepare a primer. The curing temperature is 70-90°C, preferably 75-85°C, the curing time is 1-4h, preferably 2-3h, the primer film thickness is 15-50μm, preferably 20-40μm, and the surface energy of the prepared primer is 10-20mN / m.

[0027] The ink is cured by light curing, and the wavelength of the light curing is 200-500nm, preferably 300-400nm.

[0028] Beneficial effects of the present invention:

[0029] The present invention solves the problem that ink is difficult to adhere to the surface of polypropylene by spraying a primer on the surface of a polypropylene substrate. Compared with using fluorinated polyurethane acrylate or chlorinated polypropylene as a primer alone, the chlorinated polypropylene modified by acrylic acid in the primer of the present invention can form effective adhesion with the polypropylene substrate through wetting and penetration, and the fluorinated polyurethane acrylate reduces the surface energy of the primer, so that the ink droplets with relatively high surface tension have a larger contact angle on the primer, and the morphology of the ink droplets is more convex, so that after curing, a Braille convex point with a larger aspect ratio can be formed on the primer. The primer is cured by heating, and the double bonds are not completely cross-linked. The uncross-linked double bonds can react with the double bonds in the ink, which effectively solves the problem of poor adhesion of the ink on the fluorinated low surface energy interface and ensures the effective adhesion of the ink and the primer. The photoinitiator in the primer can ensure the complete curing of the primer and the ink, and avoid the Braille convex point from falling off. Compared with the prior art, the Braille convex point prepared using the technology of the present invention has good adhesion on the polypropylene substrate, and the number of inkjet printing times required to achieve the same Braille convex point height is greatly reduced, which improves efficiency and reduces costs.

[0030] All materials and equipment in the present invention are commercially available products, and there is no need to synthesize them by oneself, which saves manufacturing time and further reduces the manufacturing cost of Braille printed products. DETAILED DESCRIPTION

[0031] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0032] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0033] The percentages in the present invention are all mass percentages unless otherwise specified; the normal temperature and room temperature in the present invention generally refer to temperatures between 15°C and 25°C, and are generally defined as 25°C.

[0034] The present invention will be further described below in conjunction with embodiments:

[0035] Embodiment 1:

[0036] 23 parts of polyurethane acrylate, 16 parts of diethylene glycol diacrylate, 32 parts of dipropylene glycol diacrylate, 17 parts of 2-methyl acrylate (5-cycloethyl-2-methyl-1,4-dioxolane), 6 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of Foamex-810, 3 parts of BYKP-105 and 1 part of p-hydroxyanisole were stirred and mixed to make an ink with a viscosity of 23 cps.

[0037] 45 parts of fluorine-containing polyurethane acrylate, 49 parts of acrylic acid-modified chlorinated polypropylene and 6 parts of 1-hydroxycyclohexyl phenyl ketone were stirred and mixed uniformly, and allowed to stand for defoaming to prepare a primer solution.

[0038] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a curing temperature of 80°C for 3 hours to prepare a polypropylene substrate covered with the primer.

[0039] The ink is filled in the resin box of the piezoelectric inkjet printer, and the ink is sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm is used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer are cross-linked and cured, and the ink shrinks spontaneously on the low surface energy primer, so that the height of the ink droplet increases. After the curing is completed, the diameter of the single-layer Braille raised point is measured to be 0.5mm, the height is 0.3mm, the height-to-diameter ratio is 0.6, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm is 3 times. The adhesion between the prepared Braille raised point and the polypropylene substrate is 260kPa.

[0040] Embodiment 2:

[0041] 21 parts of polyester acrylate, 27 parts of triethylene glycol diacrylate, 33 parts of dipropylene glycol diacrylate, 10 parts of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 5 parts of Foamex-N, 3 parts of Disperbyk-111, and 1 part of p-hydroxyanisole were stirred and mixed to prepare an ink with a viscosity of 28 cps.

[0042] 51 parts of fluorine-containing polyurethane acrylate, 42 parts of acrylic acid-modified chlorinated polypropylene and 7 parts of ethyl 2,4,6-trimethylbenzoylphenylphosphonate were stirred and mixed uniformly, and allowed to stand for defoaming to prepare a primer solution.

[0043] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a curing temperature of 75°C for 4 hours to prepare a polypropylene substrate covered with the primer.

[0044] The ink was filled in the resin box of the piezoelectric inkjet printer, and the ink was sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm was used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer were cross-linked and cured, and the ink spontaneously shrank on the low surface energy primer, so that the height of the ink droplet increased. After the curing was completed, the diameter of the single-layer Braille raised point was measured to be 0.45mm, the height was 0.3mm, the height-to-diameter ratio was 0.67, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm was 3 times. The adhesion between the prepared Braille raised point and the polypropylene substrate was 199kPa.

[0045] Embodiment 3:

[0046] 22 parts of epoxy acrylate, 29 parts of tripropylene glycol diacrylate, 21 parts of 1,6-hexanediol diacrylate, 13 parts of pentaerythritol triacrylate, 8 parts of 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone, 3 parts of Airex-920, 3 parts of RAD-2100, and 1 part of p-hydroxyanisole were stirred and mixed to make an ink with a viscosity of 26 cps.

[0047] 39 parts of fluorine-containing polyurethane acrylate, 52 parts of acrylic acid-modified chlorinated polypropylene and 9 parts of 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone were stirred and mixed uniformly, and allowed to stand for defoaming to prepare a primer solution.

[0048] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a curing temperature of 85°C for 3 hours to prepare a polypropylene substrate covered with the primer.

[0049] The ink was filled in the resin box of the piezoelectric inkjet printer, and the ink was sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm was used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer were cross-linked and cured, and the ink spontaneously shrank on the low surface energy primer, so that the height of the ink droplet increased. After the curing was completed, the diameter of the single-layer Braille raised point was measured to be 0.35mm, the height was 0.2mm, the aspect ratio was 0.57, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm was 5 times. The adhesion between the prepared Braille raised point and the polypropylene substrate was 322kPa.

[0050] Embodiment 4:

[0051] 14 parts of polyurethane acrylate, 20 parts of hyperbranched polyurethane acrylate, 13 parts of pentaerythritol tetraacrylate, 26 parts of trimethylolpropane triacrylate, 15 parts of 2-phenoxyethyl acrylate, 7 parts of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2 parts of Foamex-N, 2 parts of Rad-2200N and 1 part of p-hydroxyanisole were stirred and mixed to make an ink with a viscosity of 27 cps.

[0052] 45 parts of fluorine-containing polyurethane acrylate, 46 parts of acrylic acid-modified chlorinated polypropylene and 9 parts of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide were stirred and mixed uniformly, and allowed to stand for defoaming to prepare a primer solution.

[0053] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a temperature of 90°C for 2.5 hours to prepare a polypropylene substrate covered with the primer.

[0054] The ink is filled in the resin box of the piezoelectric inkjet printer, and the ink is sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm is used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer are cross-linked and cured, and the ink shrinks spontaneously on the low surface energy primer, so that the height of the ink droplet increases. After the curing is completed, the diameter of the single-layer Braille raised point is measured to be 0.4mm, the height is 0.25mm, the height-to-diameter ratio is 0.63, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm is 4 times. The adhesion between the prepared Braille raised point and the polypropylene substrate is 230kPa.

[0055] Embodiment 5:

[0056] 9 parts of polyurethane acrylate, 11 parts of epoxy acrylate, 9 parts of hyperbranched polyurethane acrylate, 19 parts of diethylene glycol diacrylate, 23 parts of trimethylolpropane triacrylate, 16 parts of acrylate (5-cycloethyl-2-methyl-1,4-dioxolane) 2-methyl ester, 7 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 2 parts of Foamex-810, 3 parts of Rad-2700 and 1 part of p-hydroxyanisole were stirred and mixed to make an ink with a viscosity of 31 cps.

[0057] 59 parts of fluorine-containing polyurethane acrylate, 34 parts of acrylic acid-modified chlorinated polypropylene and 7 parts of 2-hydroxy-2-methyl-1-phenylacetone were stirred and mixed uniformly, and allowed to stand for defoaming to prepare a primer solution.

[0058] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a temperature of 90°C for 2 hours to prepare a polypropylene substrate covered with the primer.

[0059] The ink is filled in the resin box of the piezoelectric inkjet printer, and the ink is sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm is used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer are cross-linked and cured, and the ink shrinks spontaneously on the low surface energy primer, so that the height of the ink drop increases. After the curing is completed, the diameter of the single-layer Braille raised point is measured to be 0.55mm, the height is 0.4mm, the height-to-diameter ratio is 0.73, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm is 2 times. The adhesion between the prepared Braille raised point and the polypropylene substrate is 137kPa.

[0060] Comparative Example 1:

[0061] 23 parts of polyurethane acrylate, 16 parts of diethylene glycol diacrylate, 32 parts of dipropylene glycol diacrylate, 17 parts of 2-methyl acrylate (5-cycloethyl-2-methyl-1,4-dioxolane), 6 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of Foamex-810, 3 parts of BYKP-105 and 1 part of p-hydroxyanisole were stirred and mixed to make an ink with a viscosity of 23 cps.

[0062] 93 parts of fluorine-containing polyurethane acrylate and 7 parts of 1-hydroxycyclohexyl phenyl ketone were stirred and mixed evenly, and allowed to stand for defoaming to prepare a primer solution.

[0063] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a curing temperature of 80°C for 3 hours to prepare a polypropylene substrate covered with the primer.

[0064] The ink was filled in the resin box of the piezoelectric inkjet printer, and the ink was sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm was used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer were cross-linked and cured, and the ink spontaneously shrank on the low surface energy primer, so that the height of the ink droplet increased. After the curing was completed, the diameter of the single-layer Braille raised point was measured to be 0.5mm, the height was 0.35mm, the aspect ratio was 0.7, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm was 3 times. The adhesion between the prepared Braille raised point and the polypropylene substrate was 44kPa.

[0065] Comparative Example 2:

[0066] 23 parts of polyurethane acrylate, 16 parts of diethylene glycol diacrylate, 32 parts of dipropylene glycol diacrylate, 17 parts of 2-methyl acrylate (5-cycloethyl-2-methyl-1,4-dioxolane), 6 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of Foamex-810, 3 parts of BYKP-105 and 1 part of p-hydroxyanisole were stirred and mixed to make an ink with a viscosity of 23 cps.

[0067] 93 parts of acrylic acid-modified chlorinated polypropylene and 7 parts of 1-hydroxycyclohexyl phenyl ketone were stirred and mixed evenly, and allowed to stand for defoaming to prepare a primer solution.

[0068] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a curing temperature of 80°C for 3 hours to prepare a polypropylene substrate covered with the primer.

[0069] The ink is filled in the resin box of the piezoelectric inkjet printer, and the ink is sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm is used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer are cross-linked and cured, and the ink shrinks spontaneously on the low surface energy primer, so that the height of the ink droplet increases. After the curing is completed, the diameter of the single-layer Braille raised point is measured to be 0.5mm, the height is 0.15mm, the height-to-diameter ratio is 0.3, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm is 6 times. The adhesion between the prepared Braille raised point and the polypropylene substrate is 220kPa.

[0070] Comparative Example 3:

[0071] 23 parts of polyurethane acrylate, 16 parts of diethylene glycol diacrylate, 32 parts of dipropylene glycol diacrylate, 17 parts of 2-methyl acrylate (5-cycloethyl-2-methyl-1,4-dioxolane), 6 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of Foamex-810, 3 parts of BYKP-105 and 1 part of p-hydroxyanisole were stirred and mixed to make an ink with a viscosity of 23 cps.

[0072] 45 parts of fluorine-containing polyurethane acrylate, 49 parts of acrylic acid-modified chlorinated polypropylene and 6 parts of 1-hydroxycyclohexyl phenyl ketone were stirred and mixed uniformly, and allowed to stand for defoaming to prepare a primer solution.

[0073] The primer liquid was sprayed onto the polypropylene substrate, and after being allowed to level at room temperature for 5 minutes, a UV curing device with an emission wavelength of 365 nm was used for light curing to prepare a polypropylene substrate covered with the primer.

[0074] The ink was filled in the resin box of the piezoelectric inkjet printer, and the ink was sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm was used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer were cross-linked and cured, and the ink spontaneously shrank on the low surface energy primer, so that the height of the ink droplet increased. After the curing was completed, the diameter of the single-layer Braille raised point was measured to be 0.5mm, the height was 0.3mm, the aspect ratio was 0.6, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm was 3 times. The adhesion between the prepared Braille raised point and the polypropylene substrate was 27kPa.

[0075] Comparative Example 4:

[0076] 23 parts of polyurethane acrylate, 65 parts of methyl methacrylate, 6 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of Foamex-810, 3 parts of BYKP-105, and 1 part of p-hydroxyanisole were stirred and mixed uniformly to prepare an ink with a viscosity of 16 cps.

[0077] 45 parts of fluorine-containing polyurethane acrylate, 49 parts of acrylic acid-modified chlorinated polypropylene and 6 parts of 1-hydroxycyclohexyl phenyl ketone were stirred and mixed uniformly, and allowed to stand for defoaming to prepare a primer solution.

[0078] The primer liquid was sprayed onto the polypropylene substrate, left to level at room temperature for 5 minutes, and then moved into an oven for heating and curing at a curing temperature of 80°C for 3 hours to prepare a polypropylene substrate covered with the primer.

[0079] The ink is filled in the resin box of the piezoelectric inkjet printer, and the ink is sprayed onto the polypropylene substrate covered with the primer. The UV curing device with an emission wavelength of 365nm is used for photocuring to completely cure the ink and the primer. During the curing process, the double bonds in the ink and the double bonds in the primer are cross-linked and cured, and the ink shrinks spontaneously on the low surface energy primer, so that the height of the ink droplet increases. After the curing is completed, the diameter of the single-layer Braille raised point is measured to be 0.5mm, the height is 0.25mm, the height-to-diameter ratio is 0.5, and the number of ink accumulations required to prepare a Braille printing point with a raised height of 1mm is 4 times. The adhesion between the prepared Braille raised point and the polypropylene substrate is 82kPa.

[0080] It can be obtained from the results of the embodiments and comparative examples that the ink and the supporting primer prepared by the method of the present invention can achieve effective adhesion and a larger height-to-diameter ratio of the braille raised points on the polypropylene substrate, thereby improving the stacking efficiency. Specifically, in Comparative Example 1, compared with Example 1, acrylic acid-modified chlorinated polypropylene is not added to the formula of the primer solution, and the adhesion of the prepared braille raised points to the substrate is reduced from 220kPa in Example 1 to 44kPa. Comparative Example 2 Compared with Example 1, fluorinated polyurethane acrylate is not added to the primer solution formula, and the height-to-diameter ratio of the prepared braille raised points is reduced from 0.6 in Example 1 to 0.3, and the number of ink stacking times required for preparing braille printing points with a raised height of 1mm is increased from 3 times in Example 1 to 6 times. Comparative Example 3 Compared with Example 1, the primer is photocured before inkjet, so that the double bond reaction in the primer is basically complete, and the adhesion of the prepared braille raised points to the substrate is reduced from 220kPa in Example 1 to 27kPa. Comparative Example 4 Compared with Example 1, the functionality of the active diluent in the ink formula is reduced to 1, the height-to-diameter ratio of the prepared Braille raised points is reduced from 0.6 in Example 1 to 0.5, the number of ink stacking times required to prepare Braille printing points with a raised height of 1 mm is increased from 3 times in Example 1 to 4 times, and the adhesion to the substrate is also reduced from 220 kPa in Example 1 to 82 kPa. In summary, the method described in the present invention can effectively improve the stacking efficiency of the Braille raised points and the adhesion to the polypropylene substrate.

[0081] The above is an exemplary description of the embodiments of the present invention. However, the protection scope of the present invention is not limited to the above embodiments. Any modification, equivalent substitution, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A Braille printing ink and a matching primer, characterized in that: The Braille inkjet printing ink is composed of 15-50 parts of a photocurable prepolymer, 15-75 parts of a reactive diluent, 5-20 parts of a photoinitiator, and 1-10 parts of an auxiliary agent; The matching primer is composed of 10-80 parts of fluorine-containing polyurethane acrylate, 10-80 parts of acrylic acid-modified chlorinated polypropylene, and 5-20 parts of photoinitiator.

2. A Braille printing ink and a matching primer according to claim 1, characterized in that: The photocurable prepolymer in the braille inkjet printing ink is one or more of polyurethane acrylate, polyester acrylate, epoxy acrylate and hyperbranched polyurethane acrylate, and the functionality of the resin is 6-12.

3. A Braille printing ink and a matching primer according to claim 1, characterized in that: The active diluent in the Braille inkjet printing ink is a mixture of diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, acrylate (5-cycloethyl-2-methyl-1,4-dioxolane) 2-methyl ester, 2-phenoxyethyl acrylate, and alkane carboxylic acid epoxy ester modified acrylic acid.

4. A Braille printing ink and a matching primer according to claim 1, characterized in that: The photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, 1-hydroxycyclohexyl phenyl ketone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylphosphonic acid ethyl ester, and 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone.

5. A Braille printing ink and a matching primer according to claim 1, characterized in that: The auxiliary agent is a defoamer, a dispersant, and an inhibitor, and the auxiliary agent brands are several of Foamex-810, Foamex-N, Airex-920, BYKP-105, Disperbyk-111, Rad-2100, Rad-2200N, Rad-2700, and p-hydroxyanisole.

6. A Braille printing ink and a matching primer according to claim 1, characterized in that: The fluorine-containing polyurethane acrylate used is a commercially available product, and examples thereof include SD-1338B (manufactured by Songda New Materials, silicon-fluorinated polyurethane acrylate resin), SF-009 (manufactured by Mo Neng Chemical, organic fluorine-modified polyurethane acrylate), and the like.

7. A Braille printing ink and a matching primer according to claim 1, characterized in that: The acrylic acid-modified chlorinated polypropylene used is a commercially available product, and the brands include PP-801 (Changzhou Sisai, chlorinated polypropylene modified acrylic resin), PP-807 (Changzhou Sisai, chlorinated polypropylene modified acrylic resin), and the like.

8. The Braille printing ink and the matching primer according to any one of claims 1 to 7 are used to prepare Braille printed products on a polypropylene substrate.

9. A method for preparing a Braille printed matter, characterized in that: The following steps are involved: 1) spraying the matching primer according to any one of claims 1 to 7 onto the area to be sprayed on the polypropylene substrate, heating and curing to obtain a partially cured primer; 2) inkjet printing the braille printing ink according to any one of claims 1 to 7 on the primer according to a predetermined pattern, and obtaining a single layer of raised braille after photocuring; 3) Multiple stacking of inkjet printing on a single layer of raised Braille dots to obtain Braille prints of a given height.

10. The preparation method according to claim 9, characterized in that: Fluorine-containing polyurethane acrylate, acrylic acid-modified chlorinated polypropylene, and photoinitiator are physically mixed, and then allowed to stand for defoaming to form a primer liquid. The primer liquid is sprayed onto the area to be sprayed on the polypropylene substrate, and then heated and cured to form a primer. The curing temperature is 70-90°C, the curing time is 1-4h, and the primer film thickness is 15-50μm. Preferably, the surface energy of the primer is 10-25 mN / m; Preferably, the height of the raised points of the single-layer Braille is 0.2 mm-0.5 mm, and the aspect ratio is 0.5-0.8.