Modified resin slurry for 3D printing as well as preparation method and application of modified resin slurry

Abstract

The invention provides modified resin slurry for 3D printing as well as a preparation method and application thereof, and relates to the technical field of 3D printing materials. The modified resin slurry for 3D printing comprises the following components in parts by weight: 40-60 parts of a photocuring prepolymer, 25-45 parts of an acrylic monomer, 5-15 parts of a composite reinforcing filler, 0.5-5 parts of a photoinitiator and 0.5-3 parts of an auxiliary agent, wherein the photocuring prepolymer is prepared from bisphenol A epoxy acrylate and aliphatic polyurethane acrylate; wherein the composite reinforcing filler comprises a silane coupling agent modified compound filler, and the compound filler comprises a rigid particle type filler and a whisker type filler. According to the modified resin slurry for 3D printing, the volume shrinkage rate of DLP printing resin can be reduced, the size precision of parts is improved, the mechanical strength of the cured resin is improved, and meanwhile, the water washing property of the material is also considered.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a modified resin slurry for 3D printing, its preparation method, and its application. Background Technology

[0002] 3D printing is a technology that constructs objects layer by layer based on digital model files. DLP (Digital Laser Printing), currently the most advanced 3D printing technology on the market, is widely used in precision parts, medical, aerospace, and jewelry industries. It uses 3D scanning to design product models, enabling rapid casting and significantly reducing manufacturing time and costs. However, after 3D printing (DLP) samples are completed, the cured material often shrinks and deforms to some extent due to the material's inherent properties and parameter settings during the curing process, leading to reduced printing accuracy. Furthermore, the uncured parts of the printed samples need to be cleaned with high-concentration alcohol. High-concentration alcohol is highly volatile and can irritate the respiratory tract with long-term use; additionally, the cleaning process is costly in large-scale parts production.

[0003] CN114874402A discloses a photocurable resin matrix comprising the following components in weight percentage: 10-35% photocurable oligomer; 45-84% reactive diluent; 5-10% binder; 0.1-5% photoinitiator; 0.1-5% light absorber; and 0.01-1% polymerization inhibitor, wherein the number average molecular weight of the photocurable oligomer is 200-2000. This resin possesses the bonding or plasticizing properties required for direct-write 3D printing technology, but it cannot effectively improve the mechanical properties and shrinkage of the cured sample, nor can it adequately address the material's inherent washability.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a modified resin slurry for 3D printing, its preparation method, and its application. The modified resin slurry for 3D printing effectively improves the mechanical properties and shrinkage of the cured sample while also taking into account the material's washability.

[0006] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a modified resin slurry for 3D printing, wherein the modified resin slurry for 3D printing comprises, by weight parts: 40-60 parts of photocurable prepolymer, 25-45 parts of acrylic monomer, 5-15 parts of composite reinforcing filler, 0.5-5 parts of photoinitiator, and 0.5-3 parts of additives; The photocurable prepolymer includes bisphenol A epoxy acrylate and aliphatic polyurethane acrylate; The composite reinforced filler includes a silane coupling agent modified composite filler, and the composite filler includes rigid particle filler and whisker filler.

[0007] Furthermore, the weight ratio of the bisphenol A epoxy acrylate to the aliphatic polyurethane acrylate is (3~5):(1~2).

[0008] Furthermore, the weight-average molecular weight of the bisphenol A epoxy acrylate is 1000~1600 g / mol.

[0009] Furthermore, the weight-average molecular weight of the aliphatic polyurethane acrylate is 1500~3000 g / mol.

[0010] Furthermore, the acrylic monomers include hydrophilic monomers, low-shrinkage monomers, and functional monomers; The hydrophilic monomer is selected from any one or a combination of at least two of the following: polyethylene glycol diacrylate, hydroxypropyl acrylate, acrylamide, tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, methoxy polyethylene glycol monoacrylate, and neopentyl glycol diacrylate. The low-shrinkage monomer is selected from isobornyl acrylate; The functional monomer is selected from propoxylated trimethylolpropane triacrylate.

[0011] Furthermore, the weight ratio of the hydrophilic monomer, the low-shrinkage monomer, and the functional monomer is (2~3):(3~4):(2~3).

[0012] Furthermore, the weight-average molecular weight of the polyethylene glycol diacrylate is 200~600 g / mol.

[0013] Furthermore, the weight ratio of the silane coupling agent, rigid particle filler and whisker filler is (0.5~5):(5~15):(1~5).

[0014] Furthermore, the particle size of the rigid particle packing is 50~300 nm.

[0015] Furthermore, the length of the whisker-type filler is 40~190 μm.

[0016] Furthermore, the silane coupling agent is selected from... c -(methacryloyloxy)propyltrimethoxysilane.

[0017] Furthermore, the rigid particle-type filler is selected from any one or a combination of at least two of silica, hydroxyapatite, glass microspheres, and single-arm carbon nanotubes.

[0018] Furthermore, the whisker-type filler is selected from any one or a combination of at least two of calcium sulfate whiskers, silicon carbide whiskers, and potassium titanate whiskers.

[0019] Furthermore, the composite reinforcing filler is prepared by the following steps: Rigid particle packing, whisker packing, and silane coupling agent are dispersed in an alcohol solvent to obtain a dispersion. The pH of the dispersion is adjusted to 4-5, and after stirring, it is filtered, washed, and dried in sequence to obtain the composite reinforced packing.

[0020] Furthermore, the alcohol solvent is an aqueous solution of 40-95 wt% ethanol.

[0021] Furthermore, the dispersion is ultrasonic dispersion; wherein the ultrasonic dispersion power is 100~300 W, and the ultrasonic dispersion time is 30~60 min.

[0022] Furthermore, the reagent used to adjust the pH of the dispersion is acetic acid.

[0023] Furthermore, the stirring treatment temperature is 60~80℃, and the stirring treatment time is 3~4 h.

[0024] Furthermore, the photoinitiator is selected from any one or a combination of at least two of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, and triarylthionium hexafluorophosphate, preferably 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0025] Furthermore, the additive is selected from any one or a combination of at least two of dispersants, defoamers, and polymerization inhibitors, preferably a combination of dispersants, defoamers, and polymerization inhibitors; Further, the weight ratio of the dispersant, defoamer, and polymerization inhibitor is (2~3):(1~1.5):(0.5~1).

[0026] Furthermore, the dispersant is selected from any one or a combination of at least two of BYK-163, BYK-110, BYK-3505, BYK-3510, ZY-7216, and FSN-5040.

[0027] Furthermore, the defoamer is selected from polyether-modified silicone defoamers, preferably any one or a combination of at least two of DF-452, D-001, DF-8201, and BYK-024.

[0028] Furthermore, the polymerization inhibitor is selected from p-hydroxyanisole.

[0029] Furthermore, the modified resin slurry for 3D printing also includes 0.05 to 0.4 parts of pigment.

[0030] In a second aspect, the present invention provides a method for preparing a modified resin slurry for 3D printing as described in the first aspect, the method comprising: Bisphenol A epoxy acrylate, aliphatic polyurethane acrylate and acrylic monomers are mixed and stirred for the first time to obtain resin matrix liquid; The resin matrix liquid, composite reinforcing filler and additives obtained in step (1) are mixed and stirred for a second time to obtain the modified resin slurry for 3D printing.

[0031] Furthermore, the first stirring speed is 700~900 r / min, and the first stirring time is 0.5~2h.

[0032] Furthermore, the second stirring speed is 700~900 r / min, and the second stirring time is 2~3 h.

[0033] Thirdly, the present invention provides an application of the modified resin slurry for 3D printing as described in the first aspect in the preparation of 3D printing resin products.

[0034] Fourthly, the present invention provides a 3D printing resin material, which is obtained by photocuring the modified resin slurry for 3D printing as described in the first aspect.

[0035] Compared with the prior art, the present invention has the following beneficial effects: (1) The modified resin slurry for 3D printing described in this invention can effectively reduce the volume shrinkage rate of DLP printing resin and improve the dimensional precision of parts. (2) The modified resin slurry for 3D printing described in this invention uses a composite filler modified with a specific silane coupling agent as a composite reinforcing filler, which can effectively improve the mechanical strength of the resin after curing. (3) The present invention can reduce environmental protection and operating costs. The product obtained after curing the modified resin slurry for 3D printing can be treated by "partial water washing + a small amount of alcohol" or by directly using 95% ethanol, thereby reducing the use of high-concentration alcohol and reducing VOC emissions. Detailed Implementation

[0036] Unless otherwise defined herein, the scientific and technical terms used in conjunction with this invention shall have the meanings commonly understood by one of ordinary skill in the art. The meaning and scope of terms shall be clear; however, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or foreign definitions. In this application, unless otherwise stated, the use of "or" means "and / or". Furthermore, the use of the term "comprising" and other forms is non-limiting.

[0037] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0039] In a first aspect, the present invention provides a modified resin slurry for 3D printing, wherein the modified resin slurry for 3D printing comprises, by weight parts: 40-60 parts of photocurable prepolymer, 25-45 parts of acrylic monomer, 5-15 parts of composite reinforcing filler, 0.5-5 parts of photoinitiator, and 0.5-3 parts of additives; The photocurable prepolymer includes bisphenol A epoxy acrylate and aliphatic polyurethane acrylate; The composite reinforced filler includes a silane coupling agent modified composite filler, and the composite filler includes rigid particle filler and whisker filler.

[0040] It should be noted that the modified resin slurry for 3D printing described in this invention adopts a composite reinforcement filler synergistic design, which effectively solves the problem of difficulty in achieving both "low shrinkage and high strength". Among them, the modified rigid particle filler can fill the gaps in the resin and reduce the curing volume shrinkage rate; the modified whisker filler (fiber reinforcement) can construct an interwoven structure in the resin system and improve mechanical strength, and the two work synergistically.

[0041] It should be noted that the modified resin slurry for 3D printing described in this invention uses bisphenol A epoxy acrylate and aliphatic polyurethane acrylate as the main resins to achieve low-toxicity and high-efficiency post-processing, reduce the use of high-concentration alcohol, and reduce VOC emissions. Furthermore, the bisphenol A epoxy acrylate (EA) in the photocurable prepolymer provides basic mechanical strength to the system, while the epoxy groups can form hydrogen bonds with hydrophilic monomers to improve system compatibility. The aliphatic polyurethane acrylate (PUA) improves the toughness of the resin, reduces the internal stress during curing, and improves warpage.

[0042] As an optional implementation, the content of photocurable prepolymer in the modified resin slurry for 3D printing is 40 to 60 parts, for example, 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, etc.

[0043] As an optional implementation, the content of acrylic monomers in the modified resin slurry for 3D printing is 25 to 45 parts, for example, 25 parts, 27 parts, 29 parts, 31 parts, 33 parts, 35 parts, 37 parts, 39 parts, 41 parts, 43 parts, 45 parts, etc.

[0044] As an optional implementation, the content of composite reinforcing filler in the modified resin slurry for 3D printing is 5 to 15 parts, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0045] As an optional implementation, the content of photoinitiator in the modified resin slurry for 3D printing is 0.5 to 5 parts, for example, it can be 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4.0 parts, 4.5 parts, 5.0 parts, etc.

[0046] As an optional implementation, the content of additives in the modified resin slurry for 3D printing is 0.5 to 3 parts, for example, 0.5 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, etc.

[0047] As an optional implementation, the weight ratio of the bisphenol A epoxy acrylate to the aliphatic polyurethane acrylate is (3~5):(1~2). Among them, "3~5" can be, for example, 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5, etc.; Among them, "1~2" can be, for example, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, etc.

[0048] As an optional embodiment, the weight-average molecular weight of the bisphenol A epoxy acrylate is 800~2000 g / mol, for example, it can be 800 g / mol, 900 g / mol, 1000 g / mol, 1100 g / mol, 1200 g / mol, 1300 g / mol, 1400 g / mol, 1500 g / mol, 1600 g / mol, 1700 g / mol, 1800 g / mol, 1900 g / mol, 2000 g / mol, etc.

[0049] In a preferred embodiment, the weight-average molecular weight of the bisphenol A epoxy acrylate is 1000~1600 g / mol.

[0050] As an optional embodiment, the weight-average molecular weight of the aliphatic polyurethane acrylate is 1500~4000 g / mol, for example, it can be 1500 g / mol, 1600 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2400 g / mol, 2500 g / mol, 2600 g / mol, 2800 g / mol, 3000 g / mol, 3200 g / mol, 3400 g / mol, 3500 g / mol, 3600 g / mol, 3800 g / mol, 4000 g / mol, etc.

[0051] In a preferred embodiment, the weight-average molecular weight of the aliphatic polyurethane acrylate is 1500~3000 g / mol.

[0052] As an optional implementation, the acrylic monomers include hydrophilic monomers, low-shrinkage monomers, and functional monomers.

[0053] As an optional implementation, the hydrophilic monomer is selected from any one or a combination of at least two of polyethylene glycol diacrylate (PEGDA), hydroxypropyl acrylate (HPA), acrylamide morpholine (ACMO), tripropylene glycol diacrylate (TPGDA), 1,6-hexanediol diacrylate (HDDA), methoxy polyethylene glycol monoacrylate (MPEGMA), and neopentyl glycol diacrylate (NPGDA).

[0054] As an optional implementation, the low-shrinkage monomer is selected from isobornyl acrylate (IBOA).

[0055] As an optional implementation, the functional monomer is selected from propoxylated trimethylolpropane triacrylate (PO-TMPTA).

[0056] It should be noted that the acrylic monomers used in this invention are a blend of "hydrophilic + low-shrinkage + functional" monomers. The hydrophilic monomers include the aforementioned polyethylene glycol diacrylate (PEGDA) and hydroxypropyl acrylate (HPA), which impart hydrophilicity to the system, enabling partial washing and improving compatibility with the prepolymer. The low-shrinkage monomers include the aforementioned isobornyl acrylate (IBOA), whose rigid structure and steric hindrance help reduce curing shrinkage. The functional monomers include the aforementioned propoxylated trimethylolpropane triacrylate (PO-TMPTA), which can increase crosslinking density to enhance strength while preventing phase separation from the prepolymer.

[0057] As an optional implementation, the weight ratio of the hydrophilic monomer, the low-shrinkage monomer, and the functional monomer is (2~3):(3~4):(2~3); Among them, the hydrophilic type "2~3" can be, for example, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, etc.; Among them, the low-shrinkage type "3~4" can be, for example, 3, 3.2, 3.4, 3.5, 3.6, 3.8, 4, etc.; Among them, the functional type "2~3" can be, for example, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, etc.

[0058] As an optional embodiment, the weight-average molecular weight of the polyethylene glycol diacrylate is 200~600 g / mol, for example, it can be 200 g / mol, 300 g / mol, 400 g / mol, 500 g / mol, 600 g / mol, etc.

[0059] As an optional implementation, the weight ratio of the silane coupling agent, rigid particle filler and whisker filler is (0.5~5):(5~15):(1~5); Among them, "0.5~5" can be, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, etc.; Among them, "5~15" can be, for example, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, etc. Wherein, "1~5" can be, for example, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, etc. As an optional embodiment, the particle size of the rigid particle packing is 50~300 nm, for example, 50 nm, 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 150 nm, 160 nm, 180 nm, 200 nm, 220 nm, 240 nm, 250 nm, 260 nm, 280 nm, 300 nm, etc.

[0060] As an optional implementation, the length of the whisker-shaped filler is 40~190 μm, for example, it can be 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 120 μm, 140 μm, 150 μm, 160 μm, 180 μm, 190 μm, etc.

[0061] As an optional implementation, the silane coupling agent is selected from... c -(methacryloyloxy)propyltrimethoxysilane.

[0062] As an optional implementation, the rigid particle-type filler is selected from any one or a combination of at least two of silica, hydroxyapatite, glass microspheres, and single-arm carbon nanotubes.

[0063] In a preferred embodiment, the rigid particle packing is selected from silica.

[0064] As an optional implementation, the whisker-type filler is selected from any one or a combination of at least two of calcium sulfate whiskers, silicon carbide whiskers, and potassium titanate whiskers.

[0065] In a preferred embodiment, the whisker-type filler is selected from calcium sulfate whiskers.

[0066] It should be noted that the composite reinforcing filler includes silane coupling agent-modified nano-silica and calcium sulfate whiskers, used to reduce shrinkage, enhance hardness, prevent agglomeration after modification, reduce the surface polarity of the filler, and improve the compatibility of the resin system. Calcium sulfate whiskers are monocrystalline fibers with high tensile strength and elastic modulus. Their aspect ratio and orientation distribution effectively disperse system stress, and their coefficient of thermal expansion is much lower than that of the resin matrix, reducing curing shrinkage and thermal deformation.

[0067] As an optional implementation, the composite reinforcing filler is prepared by the following steps: Rigid particle packing, whisker packing, and silane coupling agent are dispersed in an alcohol solvent to obtain a dispersion. The pH of the dispersion is adjusted to 4-5, and after stirring, it is filtered, washed, and dried in sequence to obtain the composite reinforced packing.

[0068] As an optional embodiment, the alcohol solvent is an aqueous solution of 40-95 wt% (e.g., 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, 95 wt%, etc.) of ethanol.

[0069] As an optional implementation, the dispersion is ultrasonic dispersion.

[0070] As an optional implementation, the ultrasonic dispersion power is 100~300 W, for example, 100 W, 150 W, 200 W, 250 W, 300 W, etc., and the ultrasonic dispersion time is 30~60 min, for example, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0071] As an optional implementation, acetic acid is used as the reagent to adjust the pH of the dispersion.

[0072] As an optional implementation, the temperature of the stirring treatment is 60~80℃, for example, 60℃, 65℃, 70℃, 75℃, 80℃, etc., and the stirring treatment time is 3~4 h, for example, 3 h, 3.2 h, 3.4 h, 3.5 h, 3.6 h, 3.8 h, 4 h, etc.

[0073] As an optional embodiment, the photoinitiator is selected from any one or a combination of at least two of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), 2-hydroxy-2-methyl-1-phenyl-1-propanone (Darocur 1173), 1-hydroxycyclohexylphenyl ketone (IRGACURE184), and triarylthionium hexafluorophosphate.

[0074] In a preferred embodiment, the photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO).

[0075] It should be noted that the preferred photoinitiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), which absorbs ultraviolet light and initiates resin curing.

[0076] As an optional implementation, the additive is selected from any one or a combination of at least two of dispersants, defoamers, and polymerization inhibitors, preferably a combination of dispersants, defoamers, and polymerization inhibitors.

[0077] As an optional implementation, the weight ratio of the dispersant, defoamer, and polymerization inhibitor is (2~3):(1~1.5):(0.5~1); Among them, "2~3" can be, for example, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, etc.; Among them, "1~1.5" can be, for example, 1, 1.1, 1.2, 1.3, 1.4, 1.5, etc.

[0078] As an optional implementation, the dispersant is selected from any one or a combination of at least two of BYK-163, BYK-110, BYK-3505, BYK-3510, ZY-7216, and FSN-5040.

[0079] As an optional implementation, the defoamer is selected from polyether modified silicone defoamers, preferably any one or a combination of at least two of DF-452, D-001, DF-8201, and BYK-024.

[0080] As an optional implementation, the polymerization inhibitor is selected from p-hydroxyanisole (MEHQ).

[0081] As an optional implementation, the modified resin slurry for 3D printing further includes 0.05 to 0.4 parts of pigment, for example, 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, etc.

[0082] It should be noted that colorants may or may not be added to the formulation of this invention. When colorants are added, there are no special limitations on the type of colorant; any colorant well-known to those skilled in the art can be used. This formulation does not contain colorants, but if necessary, colorants may be added to any formulation to adjust the color of the resin to meet appearance requirements.

[0083] In a second aspect, the present invention provides a method for preparing a modified resin slurry for 3D printing as described in the first aspect, the method comprising: Bisphenol A epoxy acrylate, aliphatic polyurethane acrylate and acrylic monomers are mixed and stirred for the first time to obtain resin matrix liquid; The resin matrix liquid, composite reinforcing filler and additives obtained in step (1) are mixed and stirred for a second time to obtain the modified resin slurry for 3D printing.

[0084] As an optional implementation, the rotation speed of the first stirring is 700~900 r / min, for example, it can be 700 r / min, 720 r / min, 740 r / min, 760 r / min, 780 r / min, 800 r / min, 820 r / min, 840 r / min, 860 r / min, 880 r / min, 900 r / min, etc., and the stirring time of the first stirring is 0.5~2 h, for example, it can be 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h, 1 h, 1.1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.7 h, 1.8 h, 1.9 h, 2 h.

[0085] As an optional implementation, the rotation speed of the second stirring is 700~900 r / min, for example, it can be 700 r / min, 720 r / min, 740 r / min, 760 r / min, 780 r / min, 800 r / min, 820 r / min, 840 r / min, 860 r / min, 880 r / min, 900 r / min, etc., and the second stirring time is 2~3 h, for example, it can be 2 h, 2.1 h, 2.2 h, 2.3 h, 2.4 h, 2.5 h, 2.6 h, 2.7 h, 2.8 h, 2.9 h, 3 h, etc.

[0086] Thirdly, the present invention provides an application of the modified resin slurry for 3D printing as described in the first aspect in the preparation of 3D printing resin products.

[0087] Fourthly, the present invention provides a 3D printing resin material, which is obtained by photocuring the modified resin slurry for 3D printing as described in the first aspect.

[0088] The present invention will be further illustrated by the following examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0089] Example 1 This embodiment provides a modified resin slurry for 3D printing, which is prepared by the following steps: (1) Preparation of composite reinforced fillers: Weigh silica (100 nm) and calcium sulfate whiskers (140 μm) in a mass ratio of 1:1.5 into a three-necked flask, add 5 wt% KH-570 silane coupling agent (4 times the total mass of the composite filler), and add 95% ethanol solution (200 W) for 30 min to allow for full dispersion. Add acetic acid to adjust the pH of the system to 5, and continue stirring in a water bath at 70°C for 3.5 h. After filtering, washing, and drying the product, the composite reinforced filler is obtained and ready for use.

[0090] (2) Preparation of modified resin slurry for 3D printing: Weigh 45 parts of prepolymer (EA:PUA=5:1, mass ratio) and 40 parts of monomer (HPA:IBOA:PO-TMPTA=2:4:3, mass ratio) according to the raw material mass fraction, and stir at 800 r / min for 1 h to obtain resin matrix liquid; weigh 10 parts of the modified inorganic filler obtained in step (1), 2.5 parts of photoinitiator (TPO) and 2.5 parts of additive (BYK3505:DF-452:MEHQ=3:1:1, mass ratio) and add them to the resin matrix liquid, and stir at 800 r / min for 2.5 h to obtain uniform modified resin slurry for 3D printing.

[0091] Example 2 This embodiment provides a modified resin slurry for 3D printing, which is prepared by the following steps: (1) Preparation of composite reinforced fillers: Weigh silica (100 nm) and calcium sulfate whiskers (140 μm) in a mass ratio of 2:1 into a three-necked flask, add KH-570 silane coupling agent (5 wt% of the total filler), and add 95% ethanol solution (4 times the total filler). Sonicate the mixture at 200 W for 30 min to allow it to disperse fully. Add acetic acid to adjust the pH of the system to 4. Continue stirring in a water bath at 60°C for 4 h. Filter, wash, and dry the product to obtain the composite reinforced filler for later use.

[0092] (2) Preparation of modified resin slurry for 3D printing: Weigh 55 parts of prepolymer (EA:PUA=3:2, mass ratio) and 30 parts of monomer (HPA:IBOA:PO-TMPTA=3:3:2, mass ratio) according to the raw material mass fraction, and stir at 700 r / min for 1 h to obtain resin matrix liquid; weigh 12 parts of the modified inorganic filler, 4 parts of photoinitiator (TPO) and 3 parts of additive (BYK3505:DF-452:MEHQ=2:1:0.5, mass ratio) obtained in step (1) and add them to the resin matrix liquid, and stir at 900 r / min for 2 h to obtain uniform modified resin slurry for 3D printing.

[0093] Example 3 This embodiment provides a modified resin slurry for 3D printing, which is prepared by the following steps: (1) Preparation of composite reinforced fillers: Weigh silica (100 nm) and calcium sulfate whiskers (140 μm) in a mass ratio of 1.5:1.2 into a three-necked flask, add 5 wt% KH-570 silane coupling agent (4 times the total mass of the composite filler), and add 95% ethanol solution (4 times the total mass of the composite filler). Sonicate at 250 W for 30 min to allow for full dispersion. Add acetic acid to adjust the pH of the system to 5. Continue stirring in a water bath at 80°C for 3 h. After filtering, washing, and drying the product, the composite reinforced filler is obtained and ready for use.

[0094] (2) Preparation of modified resin slurry for 3D printing: Weigh 50 parts of prepolymer (EA:PUA=4:1.5, mass ratio) and 35 parts of monomer (HPA:IBOA:PO-TMPTA=2.5:3.5:2.5, mass ratio) according to the raw material mass fraction, and stir at 900 r / min for 1 h to obtain resin matrix liquid; weigh 10 parts of the modified inorganic filler, 3 parts of photoinitiator (TPO) and 2 parts of additive (BYK3505:DF-452:MEHQ=2.5:1:0.8, mass ratio) obtained in step (1) and add them to the resin matrix liquid, and stir at 900 r / min for 3 h to obtain uniform modified resin slurry for 3D printing.

[0095] Example 4 This embodiment provides a modified resin slurry for 3D printing. The only difference from Embodiment 1 is that in step (1), silicon dioxide is replaced with glass microspheres of equal weight, and calcium sulfate whiskers are replaced with potassium titanate whiskers of equal weight. Other settings are the same as in Embodiment 1.

[0096] Example 5 This embodiment provides a modified resin slurry for 3D printing. The only difference from Embodiment 1 is that in step (1), silicon dioxide is replaced with an equal weight of hydroxyapatite, and calcium sulfate whiskers are replaced with an equal weight of silicon carbide whiskers. Other settings are the same as in Embodiment 1.

[0097] Example 6 This embodiment provides a modified resin slurry for 3D printing. The only difference from Example 1 is that in step (2), hydroxypropyl acrylate (HPA) is replaced with an equal weight of acrylamide (ACMO). The other settings are the same as in Example 1.

[0098] Example 7 This embodiment provides a modified resin slurry for 3D printing. The only difference from Embodiment 1 is that in step (2), hydroxypropyl acrylate (HPA) is replaced with an equal weight of neopentyl glycol diacrylate (NPGDA). The other settings are the same as in Embodiment 1.

[0099] Comparative Example 1 This comparative example provides a resin slurry, which differs from Example 3 only in that PUA is no longer added in step (2), and the amount of EA added is 45 parts. Other settings are the same as in Example 3.

[0100] Comparative Example 2 This comparative example provides a resin slurry, which differs from Example 3 only in that, in step (2), EA is no longer added, and the amount of PUA added is 45 parts. Other settings are the same as in Example 3.

[0101] Comparative Example 3 This comparative example provides a resin slurry, which differs from Example 3 only in that, in step (2), HPA is replaced with an equal weight of PEGDA, and the other settings are the same as in Example 3.

[0102] Comparative Example 4 This comparative example provides a resin slurry, which differs from Example 3 only in that HPA is no longer added in step (2), the total weight of IBOA and PO-TMPTA is maintained at 35 parts, and the ratio of IBOA:PO-TMPTA is 3.5:2.5. Other settings are the same as in Example 3.

[0103] Comparative Example 5 This comparative example provides a resin slurry, which differs from Example 3 only in that, in step (2), IBOA is no longer added, the total weight of HPA and PO-TMPTA is maintained at 35 parts, HPA:PO-TMPTA=2.5:2.5, and other settings are the same as in Example 3.

[0104] Comparative Example 6 This comparative example provides a resin slurry, which differs from Example 3 only in that, in step (2), PO-TMPTA is no longer added, the total weight of HPA and IBOA is maintained at 35 parts, HPA:IBOA=2.5:3.5, and other settings are the same as in Example 3.

[0105] Comparative Example 7 This comparative example provides a resin slurry, which differs from Example 3 only in that calcium sulfate whiskers are no longer added in step (1), while the other settings are the same as in Example 3.

[0106] Comparative Example 8 This comparative example provides a resin slurry, which differs from Example 3 only in that silica is no longer added in step (1), while the other settings are the same as in Example 3.

[0107] Comparative Example 9 This comparative example provides a resin slurry, which is prepared by the following steps: Weigh out 50 parts of prepolymer (EA:PUA=4:1.5, mass ratio) and 35 parts of monomer (HPA:IBOA:PO-TMPTA=2.5:3.5:2.5, mass ratio) according to the raw material mass fraction, and stir at 900 r / min for 1 h to obtain a resin matrix liquid; weigh out 5 parts of silica, 4 parts of calcium sulfate whiskers, 1 part of KH-570 silane coupling agent, 3 parts of photoinitiator (TPO), and 2 parts of additive (BYK3505:DF-452:MEHQ=2.5:1:0.8, mass ratio) and add them to the resin matrix liquid, and stir at 800 r / min for 2 h to obtain a uniform resin slurry.

[0108] Test case Test samples: Modified resin slurries for 3D printing provided in Examples 1-7, and resin slurries provided in Comparative Examples 1-9.

[0109] Test method: The photosensitivity of the resin was tested at a wavelength of 385-405nm and a concentration of 6000mw / cm2. The curing time was determined to be 2.8 seconds. Samples were printed, and the post-treatment was performed by ultrasonic soaking in deionized water, alcohol solution, and conventional pure alcohol for 10 minutes. The mechanical properties were then tested.

[0110] The specific test results are shown in Table 1 below: Table 1

[0111] As shown in Table 1, the modified resin slurry for 3D printing described in this invention can effectively reduce the volume shrinkage rate of DLP printing resin and improve the dimensional precision of parts; and the composite filler modified with a specific silane coupling agent as a composite reinforcing filler can effectively improve the mechanical strength of the cured resin; and the product obtained after curing the modified resin slurry for 3D printing can be subjected to "partial water washing + a small amount of alcohol" mixed post-treatment or conventional treatment, reducing the use of high-concentration alcohol and reducing VOC emissions.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A modified resin slurry for 3D printing, characterized by, The modified resin slurry for 3D printing comprises, in parts by weight, 40-60 parts of a photocuring prepolymer, 25-45 parts of an acrylic monomer, 5-15 parts of a composite reinforcing filler, 0.5-5 parts of a photoinitiator, and 0.5-3 parts of an auxiliary agent; The photocuring prepolymer comprises bisphenol A epoxy acrylate and aliphatic polyurethane acrylate; The composite reinforcing filler comprises a complex filler modified by a silane coupling agent, and the complex filler comprises a rigid particle type filler and a whisker type filler.

2. The modified resin slurry for 3D printing according to claim 1, characterized by, The weight ratio of the bisphenol A epoxy acrylate and the aliphatic polyurethane acrylate is (3-5):(1-2); Preferably, the weight average molecular weight of the bisphenol A epoxy acrylate is 1000-1600 g / mol; Preferably, the weight average molecular weight of the aliphatic polyurethane acrylate is 1500-3000 g / mol.

3. The modified resin slurry for 3D printing according to claim 1, characterized by, The acrylic monomer comprises a hydrophilic monomer, a low shrinkage monomer, and a functional monomer; The hydrophilic monomer is selected from any one or a combination of at least two of polyethylene glycol diacrylate, hydroxypropyl acrylate, acryloyl morpholine, tripropyleneglycol diacrylate, 1,6-hexanediol diacrylate, methoxy polyethylene glycol monoacrylate, and neopentyl glycol diacrylate; The low shrinkage monomer is selected from isobornyl acrylate; The functional monomer is selected from propoxylated trimethylolpropane triacrylate; Preferably, the weight ratio of the hydrophilic monomer, the low shrinkage monomer, and the functional monomer is (2-3):(3-4):(2-3); Preferably, the weight average molecular weight of the polyethylene glycol diacrylate is 200-600 g / mol.

4. The modified resin slurry for 3D printing according to claim 1, characterized by, The weight ratio of the silane coupling agent, the rigid particle type filler, and the whisker type filler is (0.5-5):(5-15):(1-5); Preferably, the particle size of the rigid particle type filler is 50-300 nm; Preferably, the length of the whisker type filler is 40-190 µm; Preferably, the silane coupling agent is selected from Preferably, the rigid particle type filler is selected from any one or a combination of at least two of silicon dioxide, hydroxyapatite, glass microbeads, and single-arm carbon nanotubes; (methacryloyloxy)propyltrimethoxysilane; Preferably, the whisker type filler is selected from any one or a combination of at least two of calcium sulfate whiskers, silicon carbide whiskers, and potassium titanate whiskers; Preferably, the composite reinforcing filler is prepared by the following steps: The rigid particle type filler, the whisker type filler, and the silane coupling agent are dispersed in an alcohol solvent to obtain a dispersion liquid; the pH of the dispersion liquid is adjusted to 4-5, and then stirring treatment is performed, followed by filtration, washing, and drying to obtain the composite reinforcing filler; Preferably, the alcohol solvent is a 40-95 wt% ethanol aqueous solution; Preferably, the dispersion is ultrasonic dispersion; the power of the ultrasonic dispersion is 100-300 W, and the ultrasonic dispersion time is 30-60 min; Preferably, the reagent for adjusting the pH of the dispersion liquid is acetic acid; Preferably, the stirring treatment temperature is 60-80 °C, and the stirring treatment time is 3-4 h. ​ 5. The modified resin slurry for 3D printing according to claim 1, characterized by, The photoinitiator is selected from any one or a combination of at least two of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone, triarylsulfonium hexafluorophosphate, preferably 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

6. The modified resin slurry for 3D printing according to claim 1, characterized by, The auxiliary agent is selected from any one or a combination of at least two of a dispersant, a defoaming agent, and a polymerization inhibitor, preferably a combination of a dispersant, a defoaming agent, and a polymerization inhibitor; Preferably, the weight ratio of the dispersant, the defoaming agent, and the polymerization inhibitor is (2~3):(1~1.5):(0.5~1); Preferably, the dispersant is selected from any one or a combination of at least two of BYK-163, BYK-110, BYK-3505, BYK-3510, ZY-7216, and FSN-5040; Preferably, the defoaming agent is selected from a polyether-modified silicone defoaming agent, preferably any one or a combination of at least two of DF-452, D-001, DF-8201, and BYK-024; Preferably, the polymerization inhibitor is selected from p-hydroxyanisole; Preferably, the modified resin slurry for 3D printing further comprises: 0.05~0.4 parts of a colorant.

7. A method of preparing the modified resin slurry for 3D printing according to any one of claims 1 to 6, characterized by, The preparation method comprises: mixing bisphenol A epoxy acrylate, aliphatic polyurethane acrylate, and acrylic monomer, and performing first stirring to obtain a resin matrix liquid; mixing the resin matrix liquid obtained in step (1), composite reinforcing filler, and auxiliary agent, and performing second stirring to obtain the modified resin slurry for 3D printing.

8. The method of preparing a modified resin slurry for 3D printing according to claim 7, characterized by, The rotation speed of the first stirring is 700~900 r / min, and the time of the first stirring is 0.5~2 h; And / or, the rotation speed of the second stirring is 700~900 r / min, and the time of the second stirring is 2~3 h.

9. Use of the modified resin slurry for 3D printing according to any one of claims 1~6 in the preparation of a 3D printing resin material.

10. A 3D printing resin material, characterized in that, The 3D printing resin material is obtained by light curing treatment of the modified resin slurry for 3D printing according to any one of claims 1~6.

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