Flexible easy-to-form 3D printing photosensitive resin and preparation method thereof

Abstract

The invention discloses a flexible easy-to-form 3D printing photosensitive resin and a preparation method thereof, and the flexible easy-to-form 3D printing photosensitive resin comprises the following components in parts by weight: 20-60 parts of a polyurethane acrylate oligomer, 0-50 parts of an acrylate oligomer, 10-80 parts of mono-functional and polyfunctional acrylate, 0.05-10 parts of a photoinitiator and 0.05-5 parts of an auxiliary agent. The invention has the following beneficial effects: when the acrylate oligomer is subjected to a photocuring reaction, the material has relatively high functionality and rigidity, after curing and molding, the material has relatively rigid performance, a high printing success rate is ensured, and through high temperature (120 DEG C) treatment, Diels-Alder reverse reaction occurs, part of chemical bonds are broken, the material hardness is reduced, and thus, the material has a very good application prospect. The toughness is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of resin preparation, and in particular to a flexible and easily moldable 3D printing photosensitive resin and a preparation method thereof. Background Art

[0002] 3D printing is a new type of manufacturing method that combines computers, new materials, and new equipment. Its principle is to slice the solid model with the help of computers, convert the manufacturing of three-dimensional objects into two-dimensional accumulation and accumulation along the molding direction, so as to complete the molding of three-dimensional objects. At present, 3D printing has been widely used in the fields of medical treatment, education, model verification, art design, jewelry, etc. The price of 3D printing materials and printing equipment based on polymers is relatively low, the raw materials are widely available, the types are diverse, and the color matching is simple, so they can be quickly popularized.

[0003] 3D printing photosensitive resin is formed through photocuring reaction. Theoretically, it is a stable thermosetting material, which makes its surface relatively solid after molding. There are also flexible 3D printing resins on the current market, but most of them use oligomers or monomers with low functionality or long aliphatic chains, which leads to very low strength of the material during molding, resulting in a low success rate of the material during photocuring molding, especially when using ordinary release film.

[0004] 3D printing photosensitive resin forms a network structure after curing, which provides strength and stability for the material. However, there are actually some chemical structures with low thermal stability. These chemical structures are formed at a relatively low temperature (higher than room temperature) and are also easy to decompose at a higher temperature, resulting in a decrease in the cross-linking density of the material, and even some ring structures that provide rigidity are opened, further reducing the hardness of the material. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems and to design a flexible and easy-to-form 3D printing photosensitive resin and a preparation method thereof.

[0006] To achieve the above-mentioned purpose, the technical solution of the present invention is a flexible and easy-to-form 3D printing photosensitive resin, which comprises the following components in parts by weight: 20-60 parts of polyurethane acrylate oligomer, 0-50 parts of acrylate oligomer, 10-80 parts of mono- and multi-functional acrylate, 0.05-10 parts of photoinitiator, and 0.05-5 parts of auxiliary agent.

[0007] As a further description of the technical solution, the polyurethane acrylate oligomer is obtained by reacting diisocyanate, hydroxyalkyl (meth)acrylate, a chain extender A containing a cis-diene structure and a chain extender B of a branched polyolefin.

[0008] As a further description of the technical solution, the chain extender A containing a cis-diolefin structure contains the following structure:

[0009]

[0010] Wherein R1~R3 ​​are any one of H or CH2, aliphatic, aromatic, polyester, epoxy, polyurethane, and polyether segments.

[0011] As a further description of this technical solution, R1 to R3 are

[0012]

[0013] One or more of; n1, n2, n3 are 1-20.

[0014] As a further description of the technical solution, the chain extender B contains the following structure:

[0015]

[0016] Among them, R4 is a polyurethane segment; n4+n5=4.

[0017] As a further description of the technical solution, the preparation of the polyurethane acrylate oligomer comprises the following raw materials calculated by mass: 10-100 parts of organic solvent, 5-30 parts of cis-diene chain extender A, 2-10 parts of N-hydroxyethylmaleimide, 2-15 parts of branched small molecule polyol, 10-40 parts of diisocyanate, 4-20 parts of hydroxyalkyl acrylate, 50-150 parts of macromolecular polyol, 0.05-5.0 parts of inhibitor, and 0.05-5.0 parts of catalyst.

[0018] As a further description of the technical solution, the method for preparing polyurethane acrylate oligomers comprises the following steps: Step (1) Preparation method of branched multi-olefin chain extender B:

[0019] Dissolve the branched small molecule polyol in an organic solvent, add diisocyanate and catalyst dropwise, stir while adding, and heat to 45-70°C. During the process, measure the NCO value of the system. When the content no longer changes, add N-hydroxyethyl maleimide to continue the reaction. When the NCO content is less than 0.05%, the reaction is considered complete, and the organic solvent is evaporated to obtain a branched polyol dilute chain extender.

[0020] Step (2) Preparation method of Diels-Alder reaction intermediate:

[0021] Dissolve the cis-diene chain extender A in an organic solvent, add the branched polyolefin chain extender B dropwise, stir while adding, wait until the liquid phase is uniform, heat to 45-75°C, react for 12-48 hours, add the product to an organic solvent, evaporating and purifying, and drying in a vacuum oven for 12-24 hours to obtain a product after Diels-Alder reaction;

[0022] Step (3) Preparation of polyurethane acrylate oligomer:

[0023] Dissolve the Diels-Alder reaction intermediate and macromolecular polyol synthesized in step (2) in an organic solvent, add diisocyanate and catalyst dropwise, stir while adding, raise the temperature to 45-70° C., and continue to stir for reaction, measure the NCO value of the system during the reaction, add hydroxyalkyl acrylate and polymerization inhibitor when it drops to 1 / 3 of the original value, continue to observe the NCO value of the reaction system, and terminate the reaction when the NCO content is less than 0.05%, and purify the polyurethane acrylate by rotary evaporation;

[0024] The organic solvent during the reaction is one or more combinations of tetrahydrofuran, dioxane, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, ethyl acetate, dimethyl sulfoxide, dichloromethane, and ether;

[0025] The cis-diene described in the reaction is one or more combinations of 2-furanmethylamine, 2-furanethylamine, 2-furanmethanol, 2-furanethanol, furan-2-methyl-phenylethylamine, 1-(2-furanyl)ethanol, N-methyl-1-(5-methyl-2-phenylfuran-3-yl)methylamine, etc.;

[0026] During the reaction, the branched small molecule polyol is one or a combination of ethylene glycol, propylene glycol, pentaerythritol, glycerol, trimethylolethane, xylitol, sorbitol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, and trimethylolpropane;

[0027] The diisocyanate blocking agent is one or more combinations of the diisocyanate selected from the group consisting of xylylene diisocyanate, isophorone diisocyanate, dimer fatty acid diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-biphenyl diisocyanate;

[0028] Hydroxyalkyl acrylate is one or more combinations of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 1,6-hexanediol diacrylate, trimethylolpropane diacrylate, pentaerythritol diacrylate, and pentaerythritol triacrylate;

[0029] The macromolecular polyol is one or more combinations of hydroxyl-terminated polyester polyol, hydroxyl-terminated polyether polyol, hydroxyl-terminated polylactic acid polyol, hydroxyl-terminated long-chain alkane diol, hydroxyl-terminated long-chain aromatic diol, hydroxyl-terminated polybutadiene, and hydroxyl-terminated ethylene oxide tetrahydrofuran copolyether;

[0030] The polymerization inhibitor is one or more combinations of hydroquinone, p-benzoquinone, methyl hydroquinone, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, p-hydroxyanisole, p-methoxyphenol, o-methylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, 1,1-diphenyl-2-trinitrophenylhydrazine, and aromatic amines;

[0031] The catalyst is one or more combinations of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, bis(dimethylaminoethyl) ether, pentamethyldiethylenetriamine, dimethylcyclohexylamine, dibutyltin dilaurate, organic bismuth, triphenylbismuth, tri(ethoxyphenyl)bismuth, ferric acetylacetonate, dibutyltin dilaurate, and triphenyltin chloride.

[0032] A method for preparing a flexible and easy-to-form 3D printing photosensitive resin comprises mixing polyurethane acrylate oligomer, acrylate oligomer, monofunctional and multifunctional acrylate, photoinitiator and auxiliary agent, and heating and stirring at below 80°C.

[0033] As a further description of the technical solution, the acrylate oligomer is a type selected from the group consisting of polyurethane acrylate, epoxy acrylate, aliphatic polyurethane acrylate, aromatic polyurethane acrylate, aromatic polyurethane acrylate, and polyester acrylate, and whether to actually use it and the amount to use it depends on the actual situation;

[0034] The mono- or multi-functional acrylate is one or more combinations of octadecyl acrylate, dodecyl acrylate, isodecyl acrylate, cyclohexanedimethanol diacrylate, alkoxylated hexanediol diacrylate, 4-acryloylmorpholine, tetrahydrofuran acrylate, 2-phenoxyethyl acrylate, isobornyl acrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, polyethylene glycol (200) diacrylate, tripropylene glycol diacrylate, trimethylolpropane formal acrylate, 1,6-hexanediol diacrylate, cyclohexanedimethanol diacrylate, tricyclodecane dimethanol diacrylate, and ethoxylated trimethylolpropane triacrylate.

[0035] As a further description of the technical solution, the photoinitiator in the photosensitive resin is a free radical polymerization photoinitiator, and the photoinitiator is at least one of 2-dimethylamino-2-benzyl-1-(4-piperidinylphenyl)-1-butanone, 1-hydroxycyclohexyl phenyl ketone, 4,4-bis(diethoxy)benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzoin dimethyl ether, benzophenone, and benzoin dimethyl ether, and is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide;

[0036] Additives include fluorescent brighteners and various colorants for adjusting print penetration.

[0037] The beneficial effect is that when the acrylate oligomer of the present invention undergoes a photocuring reaction, the material has relatively high functionality and rigidity. After curing and molding, the material has relatively rigid properties, ensuring a high printing success rate. When treated at high temperature (120°C), a Diels-Alder reverse reaction occurs, some chemical bonds are broken, the hardness of the material is reduced, and the toughness is increased. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below. A flexible and easy-to-form 3D printing photosensitive resin includes the following components in parts by weight: 20-60 parts of polyurethane acrylate oligomer, 0-50 parts of acrylate oligomer, 10-80 parts of mono- and multi-functional acrylate, 0.05-10 parts of photoinitiator, and 0.05-5 parts of auxiliary agent.

[0039] The polyurethane acrylate oligomer is obtained by reacting diisocyanate, (meth) hydroxyalkyl acrylate, a chain extender A containing a cis-diene structure and a chain extender B containing a branched polyolefin.

[0040] The chain extender A containing a cis-diolefin structure has the following structure:

[0041]

[0042] Wherein R1~R3 ​​are any one of H or CH2, aliphatic, aromatic, polyester, epoxy, polyurethane, and polyether segments.

[0043] R1~R3 are

[0044]

[0045] One or more of; n1, n2, n3 are 1-20, preferably 1-10.

[0046] Chain extender B has the following structure:

[0047]

[0048] Wherein, R4 is a polyurethane segment; n4+n5=4, preferably n4≥2.

[0049] The preparation of the polyurethane acrylate oligomer comprises the following raw materials calculated by mass: 10-100 parts of an organic solvent, 5-30 parts of a cis-diene chain extender A, 2-10 parts of N-hydroxyethyl maleimide, 2-15 parts of a branched small molecule polyol, 10-40 parts of a diisocyanate, 4-20 parts of a hydroxyalkyl acrylate, 50-150 parts of a macromolecular polyol, 0.05-5.0 parts of an inhibitor, and 0.05-5.0 parts of a catalyst.

[0050] The method for preparing a polyurethane acrylate oligomer comprises the following steps: Step (1) a method for preparing a branched polyolefin chain extender B:

[0051] Dissolve the branched small molecule polyol in an organic solvent, add diisocyanate and catalyst dropwise, stir while adding, and heat to 45-70°C. During the process, measure the NCO value of the system. When the content no longer changes, add N-hydroxyethyl maleimide to continue the reaction. When the NCO content is less than 0.05%, the reaction is considered complete, and the organic solvent is evaporated to obtain a branched polyol dilute chain extender.

[0052] Step (2) Preparation method of Diels-Alder reaction intermediate:

[0053] Dissolve the cis-diene chain extender A in an organic solvent, add the branched polyolefin chain extender B dropwise, stir while adding, wait until the liquid phase is uniform, heat to 45-75°C, react for 12-48 hours, add the product to an organic solvent, evaporating and purifying, and drying in a vacuum oven for 12-24 hours to obtain a product after Diels-Alder reaction;

[0054] Step (3) Preparation of polyurethane acrylate oligomer:

[0055] Dissolve the Diels-Alder reaction intermediate and macromolecular polyol synthesized in step (2) in an organic solvent, add diisocyanate and catalyst dropwise, stir while adding, raise the temperature to 45-70° C., and continue to stir for reaction, measure the NCO value of the system during the reaction, add hydroxyalkyl acrylate and polymerization inhibitor when it drops to 1 / 3 of the original value, continue to observe the NCO value of the reaction system, and terminate the reaction when the NCO content is less than 0.05%, and purify the polyurethane acrylate by rotary evaporation;

[0056] The organic solvent during the reaction is one or more combinations of tetrahydrofuran, dioxane, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, ethyl acetate, dimethyl sulfoxide, dichloromethane, and ether;

[0057] The cis-diene described in the reaction is one or more combinations of 2-furanmethylamine, 2-furanethylamine, 2-furanmethanol, 2-furanethanol, furan-2-methyl-phenylethylamine, 1-(2-furanyl)ethanol, N-methyl-1-(5-methyl-2-phenylfuran-3-yl)methylamine, etc.;

[0058] During the reaction, the branched small molecule polyol is one or a combination of ethylene glycol, propylene glycol, pentaerythritol, glycerol, trimethylolethane, xylitol, sorbitol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, and trimethylolpropane;

[0059] The diisocyanate blocking agent is one or more combinations of the diisocyanate selected from the group consisting of xylylene diisocyanate, isophorone diisocyanate, dimer fatty acid diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-biphenyl diisocyanate;

[0060] Hydroxyalkyl acrylate is one or more combinations of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 1,6-hexanediol diacrylate, trimethylolpropane diacrylate, pentaerythritol diacrylate, and pentaerythritol triacrylate;

[0061] The macromolecular polyol is one or more combinations of hydroxyl-terminated polyester polyol, hydroxyl-terminated polyether polyol, hydroxyl-terminated polylactic acid polyol, hydroxyl-terminated long-chain alkane diol, hydroxyl-terminated long-chain aromatic diol, hydroxyl-terminated polybutadiene, and hydroxyl-terminated ethylene oxide tetrahydrofuran copolyether;

[0062] The polymerization inhibitor is one or more combinations of hydroquinone, p-benzoquinone, methyl hydroquinone, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, p-hydroxyanisole, p-methoxyphenol, o-methylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, 1,1-diphenyl-2-trinitrophenylhydrazine, and aromatic amines;

[0063] The catalyst is one or more combinations of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, bis(dimethylaminoethyl) ether, pentamethyldiethylenetriamine, dimethylcyclohexylamine, dibutyltin dilaurate, organic bismuth, triphenylbismuth, tri(ethoxyphenyl)bismuth, ferric acetylacetonate, dibutyltin dilaurate, and triphenyltin chloride.

[0064] The polyurethane acrylate oligomer, acrylate oligomer, monofunctional acrylate, multifunctional acrylate, photoinitiator and auxiliary agent are mixed, and heated and stirred at a temperature below 80°C.

[0065] Acrylate oligomers are types of polyurethane acrylates, epoxy acrylates, aliphatic polyurethane acrylates, aromatic polyurethane acrylates, aromatic polyurethane acrylates, and polyester acrylates. Whether to use them and the amount to use them depends on the actual situation.

[0066] The mono- or multi-functional acrylate is one or more combinations of octadecyl acrylate, dodecyl acrylate, isodecyl acrylate, cyclohexanedimethanol diacrylate, alkoxylated hexanediol diacrylate, 4-acryloylmorpholine, tetrahydrofuran acrylate, 2-phenoxyethyl acrylate, isobornyl acrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, polyethylene glycol (200) diacrylate, tripropylene glycol diacrylate, trimethylolpropane formal acrylate, 1,6-hexanediol diacrylate, cyclohexanedimethanol diacrylate, tricyclodecane dimethanol diacrylate, and ethoxylated trimethylolpropane triacrylate.

[0067] The photoinitiator in the photosensitive resin is a free radical polymerization photoinitiator, and the photoinitiator is at least one of 2-dimethylamino-2-benzyl-1-(4-piperidinylphenyl)-1-butanone, 1-hydroxycyclohexyl phenyl ketone, 4,4-bis(diethoxy)benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzoin dimethyl ether, benzophenone, and benzoin dimethyl ether, and is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide;

[0068] Additives include fluorescent brighteners and various colorants for adjusting print penetration.

[0069] The following will be described in detail with reference to the embodiments and comparative examples:

[0070] Example 1

[0071] A1: Dissolve 12g of trimethylolethane in DMF, add 50.4g of hexamethylene diisocyanate, stir, heat to 45-70°C, measure the NCO value of the system, and when the NCO value drops to 1 / 2 of the initial value, add 42.3g of N-hydroxyethylmaleimide to continue the reaction, measure the NCO value, and terminate the reaction when the NCO content is less than 0.05%, and rotary evaporate and purify the polyurethane acrylate S1;

[0072] A2: 33.3 g of 2-furanethylamine is dissolved in an organic solvent, DMF, and 104.7 g of S1 synthesized in step A1 is added while stirring. When the liquid phase is uniform, the temperature is raised to 50-70° C. and the reaction is carried out for 24 hours. The product is added to an organic solvent, rotary evaporated, purified, and dried in a vacuum oven for 18-24 hours to obtain the product T1 after Diels-Alder reaction;

[0073] A3: dissolving 138 g of the Diels-Alder reaction intermediate T1 synthesized in step (2) into DMF, adding dropwise 50.4 g of hexamethylene diisocyanate and 1.5 g of dibutyltin dilaurate, raising the temperature to 45-70° C., measuring the NCO value of the system, and when the NCO value drops to 1 / 2 of the initial value, adding 600 g of macromolecular polyol PEG200, continuing to measure the NCO value, and when the NCO content is less than 0.05%, adding dropwise 50.4 g of hexamethylene diisocyanate again, stirring while adding, and continuing to stir the reaction, measuring the NCO value of the system during the reaction, and when it drops to 1 / 2 of the original value, adding 34.8 g of hydroxyethyl acrylate and 2.5 g of p-hydroxyanisole, continuing to observe the NCO value of the reaction system, and when the NCO content is less than 0.05%, terminating the reaction, rotary evaporation, and purification to obtain polyurethane acrylate U1;

[0074] A4: 35 g of the polyurethane acrylate oligomer U1 synthesized in step (3), 10 g of the polyurethane acrylate oligomer, 30 g of alkoxylated hexanediol diacrylate, 25 g of 1,4-butanediol diacrylate, 2 g of photoinitiator TPO, 0.4 g of white pulp BN02 white, and 0.02 g of black pulp BN30 black, heated and stirred at below 80° C.;

[0075] A5 prints the sample through a 3D printer to obtain sample V1, places sample V1 in a 120°C oven for 12-24 hours, and then quickly cools it to below 10°C to obtain sample W1.

[0076] Comparative Example 1

[0077] [The flexible photosensitive resin purchased from Company F on the market is sample X; the two-component light-curing 3D printing resin launched by Company E is sample Y; and the photosensitive resin prepared by the flexible oligomer provided by Company S is used as a comparison, and sample Z is printed by an LCD 3D printer;

[0078] Example 2

[0079] B1: Dissolve 6.2g of ethylene glycol in chloroform, add 44.4g of isophorone diisocyanate, stir, heat to 45-70°C, measure the NCO value of the system, and when the NCO value drops to 1 / 2 of the initial value, add 28.2g of N-hydroxyethylmaleimide to continue the reaction, measure the NCO value, and when the NCO content is less than 0.05%, terminate the reaction, and rotary evaporate and purify the polyurethane acrylate S2;

[0080] B2: Dissolve 19.4 g of 2-furanmethylamine in chloroform, an organic solvent, and dropwise add S2 synthesized in step B1, stirring while adding, and wait until the liquid phase is uniform, heat to 50-70°C, react for 24 hours, add the product to an organic solvent, rotary evaporate, purify, and dry in a vacuum oven for 18-24 hours to obtain the product T2 after Diels-Alder reaction;

[0081] B3: dissolving 92g of the Diels-Alder reaction intermediate T2 synthesized in step (2) into chloroform, adding dropwise 44.4g of isophorone diisocyanate and 1.5g of dibutyltin dilaurate, raising the temperature to 45-70°C, measuring the NCO value of the system, and when the NCO value drops to 1 / 2 of the initial value, adding 800g of hydroxy-terminated PLA with a molecular weight of 400, and continuing to measure the NCO value. When the NCO content is less than 0.05%, adding dropwise 44.4g of isophorone diisocyanate again, stirring while adding, and continuing to stir the reaction. During the reaction, measuring the NCO value of the system, when it drops to 1 / 2 of the original value, adding 26g of hydroxypropyl acrylate and 2.5g of p-hydroxyanisole, continuing to observe the NCO value of the reaction system, and when the NCO content is less than 0.05%, terminating the reaction, rotary evaporation, and purification to obtain polyurethane acrylate U2;

[0082] B4: 45 g of the polyurethane acrylate oligomer U1 synthesized in step (3), 30 g of alkoxylated hexanediol diacrylate, 25 g of 1,4-butanediol diacrylate, 2 g of photoinitiator TPO, 0.4 g of white paste BN02 white, and 0.02 g of black paste BN30 black, heated and stirred at below 80°C;

[0083] B5 prints the sample through a 3D printer to obtain sample V2, places sample V2 in a 120°C oven for 12-24 hours, and then quickly cools it to below 10 degrees Celsius to obtain sample W2.

[0084] Comparative Example 2

[0085] The flexible photosensitive resin purchased from Company F on the market is sample X; the two-component light-curing 3D printing resin launched by Company E is sample Y; and the photosensitive resin prepared by the flexible polymer provided by Company S is used as a comparison, and sample Z is printed by an LCD 3D printer;

[0086] Example 3

[0087] C1: Dissolve 7.6 g of 1,2-propylene glycol in DMF, add 52.4 g of dicyclohexylmethane diisocyanate, stir, heat to 45-70°C, measure the NCO value of the system, and when the NCO value drops to 1 / 2 of the initial value, add 28.2 g of N-hydroxyethylmaleimide to continue the reaction, measure the NCO value, and terminate the reaction when the NCO content is less than 0.05%, and rotary evaporate and purify the polyurethane acrylate S3;

[0088] C2: Dissolve 19.6 g of 2-furanmethanol in an organic solvent, DMF, and dropwise add S3 synthesized in step C1 while stirring. When the liquid phase is uniform, heat to 50-70° C., react for 24 hours, add the product to an organic solvent, evaporating and purifying, and drying in a vacuum oven for 18-24 hours to obtain the product T3 after Diels-Alder reaction.

[0089] C3: dissolving 107.8 g of the Diels-Alder reaction intermediate T3 synthesized in step (2) into DMF, adding dropwise 52.4 g of dicyclohexylmethane diisocyanate and 1.5 g of dibutyltin dilaurate, raising the temperature to 45-70° C., measuring the NCO value of the system, and when the NCO value drops to 1 / 2 of the initial value, adding 400 g of macromolecular polyol PEG200, continuing to measure the NCO value, and when the NCO content is less than 0.05%, adding dropwise 52.4 g of dicyclohexylmethane diisocyanate again, stirring while adding, and continuing to stir the reaction, measuring the NCO value of the system during the reaction, and when the NCO value drops to 1 / 2 of the original value, adding 37.6 g of hydroxyethyl methacrylate and 2.5 g of p-hydroxyanisole, continuing to observe the NCO value of the reaction system, and when the NCO content is less than 0.05%, terminating the reaction, rotary evaporation, and purification to obtain polyurethane acrylate U3;

[0090] C4: 45 g of the polyurethane acrylate oligomer U1 synthesized in step (3), 30 g of alkoxylated hexanediol diacrylate, 25 g of 1,4-butanediol diacrylate, 2 g of photoinitiator TPO, 0.4 g of white pulp BN02 white, and 0.02 g of black pulp BN30 black, heated and stirred at below 80° C.;

[0091] C5 prints the sample through a 3D printer to obtain sample V3, places sample V3 in a 120°C oven for 12-24 hours, and then quickly cools it to below 10 degrees Celsius to obtain sample W3.

[0092] Comparative Example 3

[0093] The flexible photosensitive resin purchased from Company F on the market is sample X; the two-component light-curing 3D printing resin launched by Company E is sample Y; and the photosensitive resin prepared by the flexible polymer provided by Company S is used as a comparison, and sample Z is printed by an LCD 3D printer;

[0094] Example 4

[0095] D1: Dissolve 9g 1,4-butanediol in DMF, add 36.4g hydrogenated xylene diisocyanate, stir, heat to 45-70°C, measure the NCO value of the system, and when the NCO value drops to 1 / 2 of the initial value, add 28.2g N-hydroxyethylmaleimide to continue the reaction, measure the NCO value, and terminate the reaction when the NCO content is less than 0.05%, and rotary evaporate and purify the polyurethane acrylate S4;

[0096] D2: Dissolve 22.4 g of 2-furanethyl in an organic solvent, DMSO, and dropwise add S4 synthesized in step A1, stirring while adding, and wait until the liquid phase is uniform, heat to 50-70°C, react for 24 hours, add the product to an organic solvent, rotary evaporate, purify, and dry in a vacuum oven for 18-24 hours to obtain the product T4 after Diels-Alder reaction;

[0097] 96 g of the Diels-Alder reaction intermediate T3 synthesized in step (2) was dissolved in DMF, 36.4 g of hydrogenated xylylene diisocyanate and 1.5 g of dibutyltin dilaurate were added dropwise, the temperature was raised to 45-70° C., the NCO value of the system was measured, when the NCO value dropped to 1 / 2 of the initial value, 600 g of macromolecular polyol PEG200 was added, and the NCO value was continuously measured, when the NCO content was less than 0.05%, 36.4 g of hydrogenated xylylene diisocyanate was added dropwise again, stirring while adding, and the stirring reaction was continued, the NCO value of the system was measured during the reaction, when it dropped to 1 / 2 of the original value, 34.8 g of hydroxyethyl acrylate and 2.5 g of p-hydroxyanisole were added, the NCO value of the reaction system was continuously observed, when the NCO content was less than 0.05%, the reaction was terminated, and the polyurethane acrylate U1 was obtained by rotary evaporation and purification;

[0098] 45g of the polyurethane acrylate oligomer U1 synthesized in step (3), 30g of alkoxylated hexanediol diacrylate, 25g of 1,4-butanediol diacrylate, 2g of photoinitiator TPO, 0.4g of white pulp BN02 white, and 0.02g of black pulp BN30 black were heated and stirred at below 80°C;

[0099] D5 prints the sample through a 3D printer to obtain sample V4, places sample V4 in a 120°C oven for 12-24 hours, and then quickly cools it to below 10 degrees Celsius to obtain sample W4.

[0100] Comparative Example 4

[0101] The flexible photosensitive resin purchased from Company F on the market is sample X; the two-component light-curing 3D printing resin launched by Company E is sample Y; and the photosensitive resin prepared by the flexible polymer provided by Company S is used as a comparison, and sample Z is printed by an LCD 3D printer;

[0102] Table 1 is a performance test table of Example 1-4 and comparative examples

[0103]

[0104]

[0105] After post-processing of traditional 3D printing light-curing materials, the hardness and strength of the materials are enhanced. However, the present invention cleverly utilizes the reverse reaction of the Diels-Alder reaction heating to cause partial molecular chain breakage, thereby reducing the hardness of the material and increasing its toughness.

[0106] Traditional 3D printing flexible materials have low strength during initial molding, and ordinary printers have low molding rates, wasting time and materials. The material strength during printing of the present invention is moderate, with a higher molding rate and hardness. The flexibility and toughness of the material itself are obtained through post-processing, and there is no problem of short construction life of the dual-curing system.

[0107] When the acrylate oligomer of the present invention undergoes a photocuring reaction, the material has relatively high functionality and rigidity. After curing and molding, the material has relatively rigid properties, ensuring a high printing success rate. When treated at high temperature (120° C.), a Diels-Alder reverse reaction occurs, some chemical bonds are broken, the hardness of the material is reduced, and the toughness is increased.

[0108] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Some changes that may be made to certain parts thereof by technicians in this technical field all reflect the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A flexible and easy-to-shape 3D printing photosensitive resin, characterized in that: The invention comprises the following components in parts by weight: 20-60 parts of polyurethane acrylate oligomer, 0-50 parts of acrylate oligomer, 10-80 parts of mono- or multi-functional acrylate, 0.05-10 parts of photoinitiator and 0.05-5 parts of auxiliary agent.

2. A flexible and easily moldable 3D printing photosensitive resin according to claim 1, characterized in that: The polyurethane acrylate oligomer is obtained by reacting diisocyanate, (meth) hydroxyalkyl acrylate, a chain extender A containing a cis-diene structure and a chain extender B containing a branched polyolefin.

3. A flexible and easily moldable 3D printing photosensitive resin according to claim 2, characterized in that: The chain extender A containing a cis-diolefin structure has the following structure: Wherein R1~R3 ​​are any one of H or CH2, aliphatic, aromatic, polyester, epoxy, polyurethane, and polyether segments.

4. A flexible and easily moldable 3D printing photosensitive resin according to claim 3, characterized in that: R1~R3 are One or more of; n1, n2, n3 are 1-20.

5. A flexible and easily moldable 3D printing photosensitive resin according to claim 4, characterized in that: Chain extender B has the following structure: Among them, R4 is a polyurethane segment; n4+n5=4.

6. The flexible and easily moldable 3D printing photosensitive resin according to claim 1, characterized in that: The preparation of the polyurethane acrylate oligomer comprises the following raw materials calculated by mass: 10-100 parts of an organic solvent, 5-30 parts of a cis-diene chain extender A, 2-10 parts of N-hydroxyethyl maleimide, 2-15 parts of a branched small molecule polyol, 10-40 parts of a diisocyanate, 4-20 parts of a hydroxyalkyl acrylate, 50-150 parts of a macromolecular polyol, 0.05-5.0 parts of an inhibitor, and 0.05-5.0 parts of a catalyst.

7. A flexible and easily moldable 3D printing photosensitive resin according to claim 6, characterized in that: The method for preparing a polyurethane acrylate oligomer comprises the following steps: Step (1) a method for preparing a branched polyolefin chain extender B: Dissolve the branched small molecule polyol in an organic solvent, add diisocyanate and catalyst dropwise, stir while adding, and heat to 45-70°C. During the process, measure the NCO value of the system. When the content no longer changes, add N-hydroxyethyl maleimide to continue the reaction. When the NCO content is less than 0.05%, the reaction is considered complete, and the organic solvent is evaporated to obtain a branched polyol dilute chain extender. Step (2) Preparation method of Diels-Alder reaction intermediate: Dissolve the cis-diene chain extender A in an organic solvent, add the branched polyolefin chain extender B dropwise, stir while adding, wait until the liquid phase is uniform, heat to 45-75°C, react for 12-48 hours, add the product to an organic solvent, evaporating and purifying, and drying in a vacuum oven for 12-24 hours to obtain a product after Diels-Alder reaction; Step (3) Preparation of polyurethane acrylate oligomer: Dissolve the Diels-Alder reaction intermediate and macromolecular polyol synthesized in step (2) in an organic solvent, add diisocyanate and catalyst dropwise, stir while adding, raise the temperature to 45-70° C., and continue to stir for reaction, measure the NCO value of the system during the reaction, add hydroxyalkyl acrylate and polymerization inhibitor when it drops to 1 / 3 of the original value, continue to observe the NCO value of the reaction system, and terminate the reaction when the NCO content is less than 0.05%, and purify the polyurethane acrylate by rotary evaporation; The organic solvent during the reaction is one or more combinations of tetrahydrofuran, dioxane, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, chloroform, ethyl acetate, dimethyl sulfoxide, dichloromethane, and ether; The cis-diene described in the reaction is one or more combinations of 2-furanmethylamine, 2-furanethylamine, 2-furanmethanol, 2-furanethanol, furan-2-methyl-phenylethylamine, 1-(2-furanyl)ethanol, N-methyl-1-(5-methyl-2-phenylfuran-3-yl)methylamine, etc.; During the reaction, the branched small molecule polyol is one or a combination of ethylene glycol, propylene glycol, pentaerythritol, glycerol, trimethylolethane, xylitol, sorbitol, 1,2-propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, and trimethylolpropane; The diisocyanate blocking agent is one or more combinations of the diisocyanate selected from the group consisting of xylylene diisocyanate, isophorone diisocyanate, dimer fatty acid diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-biphenyl diisocyanate; Hydroxyalkyl acrylate is one or more combinations of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, 1,6-hexanediol diacrylate, trimethylolpropane diacrylate, pentaerythritol diacrylate, and pentaerythritol triacrylate; The macromolecular polyol is one or more combinations of hydroxyl-terminated polyester polyol, hydroxyl-terminated polyether polyol, hydroxyl-terminated polylactic acid polyol, hydroxyl-terminated long-chain alkane diol, hydroxyl-terminated long-chain aromatic diol, hydroxyl-terminated polybutadiene, and hydroxyl-terminated ethylene oxide tetrahydrofuran copolyether; The polymerization inhibitor is one or more combinations of hydroquinone, p-benzoquinone, methyl hydroquinone, 2-tert-butylhydroquinone, 2,5-di-tert-butylhydroquinone, p-hydroxyanisole, p-methoxyphenol, o-methylhydroquinone, 2,6-di-tert-butyl-4-methylphenol, 1,1-diphenyl-2-trinitrophenylhydrazine, and aromatic amines; The catalyst is one or more combinations of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, N,N,N',N'-tetramethylalkylenediamine, triethylamine, N,N-dimethylbenzylamine, bis(dimethylaminoethyl) ether, pentamethyldiethylenetriamine, dimethylcyclohexylamine, dibutyltin dilaurate, organic bismuth, triphenylbismuth, tri(ethoxyphenyl)bismuth, ferric acetylacetonate, dibutyltin dilaurate, and triphenyltin chloride.

8. A method for preparing a flexible and easily moldable 3D printing photosensitive resin as described in any one of claims 1 to 7, characterized in that: The polyurethane acrylate oligomer, acrylate oligomer, monofunctional acrylate, multifunctional acrylate, photoinitiator and auxiliary agent are mixed, and heated and stirred at a temperature below 80°C.

9. The method for preparing a flexible and easily moldable 3D printing photosensitive resin according to claim 8, characterized in that: Acrylate oligomers are types of polyurethane acrylates, epoxy acrylates, aliphatic polyurethane acrylates, aromatic polyurethane acrylates, aromatic polyurethane acrylates, and polyester acrylates. Whether to use them and the amount to use them depends on the actual situation. The mono- or multi-functional acrylate is one or more combinations of octadecyl acrylate, dodecyl acrylate, isodecyl acrylate, cyclohexanedimethanol diacrylate, alkoxylated hexanediol diacrylate, 4-acryloylmorpholine, tetrahydrofuran acrylate, 2-phenoxyethyl acrylate, isobornyl acrylate, 1,4-butanediol diacrylate, diethylene glycol diacrylate, polyethylene glycol (200) diacrylate, tripropylene glycol diacrylate, trimethylolpropane formal acrylate, 1,6-hexanediol diacrylate, cyclohexanedimethanol diacrylate, tricyclodecane dimethanol diacrylate, and ethoxylated trimethylolpropane triacrylate.

10. The method for preparing a flexible and easily moldable 3D printing photosensitive resin according to claim 9, characterized in that: The photoinitiator in the photosensitive resin is a free radical polymerization photoinitiator, and the photoinitiator is at least one of 2-dimethylamino-2-benzyl-1-(4-piperidinylphenyl)-1-butanone, 1-hydroxycyclohexyl phenyl ketone, 4,4-bis(diethoxy)benzophenone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, benzoin dimethyl ether, benzophenone, and benzoin dimethyl ether, and is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide or phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; Additives include fluorescent brighteners and various colorants for adjusting print penetration.

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