A super low viscosity binder for a three-dimensional jetting molding process and a method of preparing the same

Abstract

A kind of ultra-low viscosity binder for three-dimensional jet forming process and its preparation method belong to three-dimensional printing technical field.It is divided into A, B two components, A component is reinforcing agent, generates " molecular bridge " in powder and adhesive and enhances bonding strength, includes double reactive monomer, diluent, PH regulator, stabilizer;B component is adhesive, including epoxy resin, curing agent, diluent, surface tension regulator, anti-jet head blocking agent.The binder jetting 3D printing technology of the application is double-jet head jet forming, in the printing process, first jet A component, then jet B component, keep 80-110 DEG C constant temperature, A component is dehydrated and condensed after contact with powder and generates chemical bond with powder surface hydrogen bond, after printing, solidification forming, A component and B component occur chemical bonding, generate printing green body.The method is suitable for metal and ceramic powder, the ash residue of the adhesive is extremely low, can improve the density and strength of final product.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of additive manufacturing, and particularly relates to a binder for binder jetting 3D printing technology and a preparation method. BACKGROUND

[0002] Binder Jetting Printing (BJP) is also known as Three-Dimension Printing (3DP). This technology is based on the principle of micro-droplet jetting, and loose powder is selectively jetted according to the designed path of the computer, and then is accumulated layer by layer to form a product, and finally the desired product is obtained after post-processing.

[0003] Currently, the binder jetting forming technology mainly uses water-based binder and organic solvent-based binder for metal powder binder. The main adhesive components of the water-based binder are PVA, PVP, PVB and other water-soluble polymers. After the binder is sprayed onto the surface of the powder, the water needs to be heated to promote the volatilization of the water (the cavity needs to be kept at 40-80℃), and a layer of polar polymer film is generated on the surface of the powder to produce adhesive strength. Therefore, solid binders (PVA, PVP, PVB or starch) need to be added to the solid powder to enhance the strength of the green body. Due to the difference in density and surface polarity between the powder and the solid binder, the doped solid binder is prone to uneven distribution and precipitation from the powder, which affects the strength and accuracy of the green body. The ProMetal RTS-300 printer of ExOne Company and the HP Metal Jet metal 3D printer of Hewlett-Packard Company both use the above method for metal printing. The 3D printer developed by Wuhan Yizhi pushes a phenolic adhesive. The adhesive has high adhesive strength, high curing temperature (generally 200℃ for 2h), and high carbon residue of phenolic, which affects the final metal composition and further affects the strength. The UV adhesive has excellent storage stability, adjustable viscosity and low ash residue, but it needs to be cured by ultraviolet light, which requires the addition of a light curing component, making the machine structure more complex and increasing the cost of the equipment.

[0004] In view of the existing problems, the present application aims to prepare a super-low viscosity two-component adhesive. The A component is a reinforcing agent, and the B component is an adhesive. After hydrolysis, the A component can form a chemical bond with the hydroxyl group on the surface of the inorganic powder, and the other end can react with the epoxy group to form a "molecular bridge" in the powder and the B component adhesive, thereby improving the strength of the green body. The B component is a single-component epoxy adhesive. The adhesive does not cure at room temperature, can be cured at medium temperature, has low ash residue, low viscosity, can be jetted by using a common commercial nozzle, and has low curing temperature (curing temperature is 130-150℃). Therefore, the present application can reduce the manufacturing cost of the 3DP equipment, reduce energy consumption and is environmentally friendly. SUMMARY

[0005] The present application aims at solving the problems of the prior art and providing a two-component ultra-low viscosity adhesive for 3DP process and a preparation method thereof.

[0006] The adhesive of the present application has very small viscosity and no insoluble substance. The present application has low requirements for 3DP machine and nozzle, and the adhesive has wide adaptability, and a commercial nozzle with low price can be used.

[0007] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0008] The present application provides a two-component adhesive for 3DP printing process, characterized in that the two-component adhesive comprises A and B components, the A component is a reinforcing agent, and the B component is an adhesive.

[0009] The formula of the A component is shown in the following table

[0010]

[0011] The present application also provides a preparation method of the A component reinforcing agent, comprising the following steps:

[0012] S1, preparing a 10% aqueous solution of a pH regulator for standby; the pH regulator is an acid or a base;

[0013] S2, adding a double-reactive monomer to a diluent solvent and stirring for standby;

[0014] S3, adding the pH regulator in S1 to the system in S2 while stirring, and adjusting the pH value to be acidic or alkaline;

[0015] S4, adding a stabilizer to the system in S3 while stirring, and continuously stirring for 30-60 minutes until the solution becomes completely transparent and the hydrolysis is completed, and then printing on a machine can be performed;

[0016] When the double-reactive monomer is 3-aminopropyltrimethoxysilane or γ-glycidoxypropyltrimethoxysilane, S3 is adjusted to be acidic, and the pH value is adjusted to be 3-6; when the double-reactive monomer is N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane or γ-aminopropyltriethoxysilane, S3 is adjusted to be alkaline, and the pH value is adjusted to be 8-11;

[0017] The formula of the B component adhesive is shown in the following table

[0018]

[0019]

[0020] The application also provides a preparation method of the B component adhesive, comprising the following steps:

[0021] X1, mechanically stirring the base material in the diluent until the base material is completely dissolved;

[0022] X2, adding the blowout preventer blocking agent and the surface tension regulator into the mixture obtained in X1 while mechanically stirring;

[0023] X3, adding the latent curing agent into the mixture obtained in X2 while stirring, mechanically stirring for 30 min, ultrasonicating, and filtering, thereby obtaining the transparent and uniform adhesive.

[0024] The method for the three-dimensional jet forming process of the ultra-low viscosity adhesive comprises the following steps: respectively feeding the A component adhesive and the B component adhesive into a machine, jetting a layer of powder containing hydroxyl groups, jetting a layer of the A component first, jetting a layer of the B component, jetting the powder-A component-B component multiple times, maintaining the powder temperature in the forming chamber in the range of 80-110 DEG C, making the silicon hydroxyl groups of the A component and the hydroxyl groups on the surface of the powder dehydrate and condense to generate chemical bonds, and after the printing of the whole product is completed, heating the whole forming chamber at a temperature of 130-150 DEG C for 1-3 h, so that the B adhesive is cured and the amino groups or the epoxy groups of the A component are bonded with the epoxy groups of the B component, a "molecular bridge" is generated between the powder and the epoxy adhesive, the bonding strength of the epoxy to the powder is increased, and finally a high-strength green part is obtained.

[0025] The further powder is any one or more of metal powder, alumina, zirconia ceramic powder and the like, and the metal powder comprises stainless steel powder, nickel alloy, titanium alloy, cobalt-chromium alloy and the like; and after the whole product is cured, the debinding and sintering processes are performed.

[0026] The application has the advantages that: the A component and the B component have a viscosity lower than 6 mPa s, which is suitable for the 3DP printing process; the "molecular bridge" is generated between the powder and the adhesive due to the presence of the A component, and the bonding strength of the B component adhesive is increased; the A component and the B component have extremely low viscosity, the adhesive has wide adaptability, the requirement for the nozzle is reduced, a commercial nozzle with low cost can be used, and the equipment cost is reduced; in addition, the process does not need to treat the powder to achieve the required green part strength, the requirement for the powder is low, the range of printable powder is wide, the ash residue of the adhesive is extremely low, the density and strength of the final product can be improved, and the metal powder, alumina and zirconia ceramic powder can be directly printed. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structural schematic diagram of a metal 3D forming equipment; in the figure: 1, nozzle A, 2, nozzle B, 3, forming cylinder, 4, printed part, 5, powder collecting chamber, 6, powder spreading roller, 7, powder supply cylinder.

[0028] Figure 2 is a green part drawing of a 316L stainless steel metal printed part provided in Example 1.

[0029] Figure 3 is a physical drawing of a 316L stainless steel metal sintered part provided in Example 1.

[0030] Figure 4 is a green part drawing of a 17-4PH stainless steel metal printed part provided in Example 2.

[0031] Figure 5 is a green part drawing of a 420 stainless steel metal printed part provided in Example 3.

[0032] Figure 6 is a green part drawing of a zirconium oxide ceramic printed part provided in Example 4. DETAILED DESCRIPTION

[0033] Hereinafter, the contents of the present application will be described in detail. The description of the technical features described below is based on representative embodiments, specific examples of the present application, but the present application is not limited to these embodiments, specific examples. Note that:

[0034] In the present specification, the numerical range represented by "numerical value A to numerical value B" means a range including the end point numerical values A and B.

[0035] In the present specification, for the metal powder 3DP process of the embodiments of the present application, a piezoelectric nozzle inkjet printing technology is used. The printing process is similar to the printing process, which is a linear motion, and multiple nozzles can be used in combination as needed to further improve the printing efficiency. The appropriate binder and piezoelectric nozzle are matched for use on metal powder, which helps to shorten the 3D printing time and achieve the purpose of rapid prototyping.

[0036] EMBODIMENTS

[0037] The present application will be specifically described by the following examples, but the present application is not limited to the present examples.

[0038] <evaluation method>

[0039] The viscosity of the adhesive in the present example is measured by a Brookfield DV3T rotary viscometer, and the test temperature is 25°C.

[0040] The surface tension of the adhesive in the present example is measured by the pendant drop method using a DataPhysics OCA20 contact angle measuring instrument.

[0041] The bending strength of the green part after printing in the present example is measured by GB / T 9341-2008.

[0042] The tensile strength of the metal piece after sintering in this embodiment is measured by MPIF 10 of the United States.

[0043] The density of the metal piece after sintering in this embodiment is measured by GB / T 3850-2015 Archimedes drainage method.

[0044] The hardness of the metal piece after sintering in this embodiment is measured by GB / T 230.1-2004.

[0045] The bending strength of the ceramic piece after sintering in this embodiment is measured by GB / T 6569-2006.

[0046] The density of the ceramic piece after sintering in this embodiment is measured by ISO 18754-2013.

[0047] Example 1

[0048] Table 1 Formulation table of Example 1

[0049] Formulation of Group A

[0050] Ingredient Name Mass percent / % Bireactive monomer 3-aminopropyltrimethoxysilane 4 Dilution solvent Water 50 Dilution solvent Ethanol 45.84 Stabilizer Ethylene glycol 0.16

[0051] Formulation of Group B

[0052] Ingredient Name Mass percent / % Base Epoxy equivalent weight 176-184 30 Curing agent 3-phenyl-l,l-dimethylurea 1.5 Diluent Ethylene glycol methyl ether 38.4 Diluent Ethanol 25 Surface tension modifier Polydimethylsiloxane 0.08 Surface tension modifier Polyether-modified organosiloxane 0.02 Anti-foam 1,2-propanediol 5

[0053] The following operations are performed according to the Group A component formulation in the above table:

[0054] S1, citric acid is prepared into a 10% aqueous solution as a pH regulator for standby;

[0055] S2, the double reactive monomer 3-aminopropyltrimethoxysilane is added to the mixed solvent of water and ethanol and stirred for standby;

[0056] S3, the pH regulator in S1 is added dropwise to the S2 system while stirring, and the pH value is adjusted to 6;

[0057] S4, the stabilizer is added to the S3 system while stirring, and the stirring is continued for 30-60 minutes until the solution becomes completely transparent and the hydrolysis is completed, and the printing can be performed.

[0058] The viscosity and surface tension of the Group A component prepared above are tested at room temperature (25℃), and the viscosity of the adhesive is measured to be 2.13 mPa·s, and the surface tension is 28.93 mN·m -1 .

[0059] The following operations are performed according to the Group B component formulation in the above table:

[0060] X1, the epoxy resin is placed in a mixed solution of diluent ethylene glycol methyl ether and ethanol and mechanically stirred until the epoxy resin is completely dissolved;

[0061] X2, to the mixture after X1 is mixed, 1,2-propanediol, polydimethylsiloxane, polyether modified organosiloxane are added while mechanically stirring.

[0062] X3, to the mixture after X2 is mixed, latent curing agent 3-phenyl-1,1-dimethylurea is added while stirring, mechanically stirring for 30 min, ultrasonic, filtration, and a transparent and uniform adhesive is prepared.

[0063] The viscosity and surface tension of the B component prepared above are tested at room temperature (25℃), and the viscosity of the adhesive is 5.46 mPa·s and the surface tension is 43.22 mN·m -1 .

[0064] The use method of the adhesive is as follows: a) introducing the required printing model on the metal 3DP equipment; b) adding the prepared A and B components into the A and B ink storage tanks respectively, and placing 316L stainless steel powder (commercially available from Xi'an Ouzhong Material Technology Co., Ltd., with hydroxyl groups on the surface and a particle size range of 15-45 μm) in the powder supply cylinder, keeping the temperature of the forming cylinder and the powder supply cylinder constant at 95℃; c) performing printing operation, every time a layer of powder is laid, the nozzle sprays A component first, then B component according to the computer designed path, then the forming cylinder is lowered by one layer, the powder supply cylinder is raised by one layer, the powder is laid on the forming cylinder by the powder laying roller, and A and B components are sprayed in sequence again, layer by layer, and finally the uncured green part is obtained; d) placing the forming cylinder containing the green part in a 150℃ oven for 2h heating and curing, removing the excess powder, and obtaining the required green part; e) performing the debinding and sintering process of the green part under vacuum conditions (increasing from room temperature to 300℃ at a rate of 3℃ / min, keeping for 0.5h; increasing to 600℃ at a rate of 2℃ / min, keeping for 1h to complete debinding; increasing to 1360℃ at a rate of 4℃ / min, keeping for 2h to complete sintering, and finally cooling to room temperature with the furnace), and finally obtaining the required metal part.

[0065] After testing, the strength of the printed green part is 10.23 MPa, the strength of the sintered part is 475 MPa, the density of the sintered part is 98.9%, and the hardness of the sintered part is 62 HRB.

[0066] Example 2

[0067] Table 2 Formulation Table of Example 2

[0068] Formulation of A component

[0069]

[0070] Formulation of B component

[0071] Ingredient Name Mass percent / % Base Epoxy equivalent weight 210-230 20 Curing agent 3-phenyl-l,l-dimethylurea 1.0 Diluent Ethylene glycol butyl ether 56.95 Diluent Ethanol 20 Surface tension modifier Polyether-modified organosiloxane 0.05 Anti-foam Glycerol 2

[0072] According to the following Table A group component formula, the following operations are performed:

[0073] S1, sodium hydroxide is prepared into a 10% aqueous solution as a pH regulator for standby;

[0074] S2, the double reactive monomer N-β-(aminoethyl)-γ-aminopropyl trimethoxysilane is added to the mixed solvent of water and methanol and stirred for standby;

[0075] S3, the pH regulator in S1 is added dropwise to the S2 system while stirring, and the pH value is adjusted to 10;

[0076] S4, the stabilizer ethylene glycol is added to the S3 system while stirring, and the stirring is continued for 30-60 minutes until the solution becomes completely transparent, the hydrolysis is completed, and the printing on the machine can be performed.

[0077] The viscosity and surface tension of the A group component prepared above are tested at room temperature (25℃), and the viscosity of the adhesive is 1.89 mPa·s, and the surface tension is 25.46 mN·m -1 .

[0078] According to the following Table B group component formula, the following operations are performed:

[0079] X1, the epoxy resin is placed in a mixed solution of diluent ethylene glycol butyl ether and ethanol and mechanically stirred to dissolve the epoxy resin completely;

[0080] X2, to the mixture after X1 is mixed uniformly, add glycerol, polyether modified organosiloxane while mechanically stirring.

[0081] X3, add latent curing agent 3-phenyl-1,1-dimethylurea to the X2 mixture while stirring, mechanically stir for 30 min, ultrasonic, filter, and prepare a transparent and uniform adhesive.

[0082] The viscosity and surface tension of the B group component prepared above are tested at room temperature (25℃), and the viscosity of the adhesive is 4.77 mPa·s, and the surface tension is 41.52 mN·m -1 .

[0083] The binder use method is: a) introducing the required printing model on the metal 3DP equipment; b) adding the prepared A, B components into A, B ink storage tanks respectively, and placing 17-4PH stainless steel metal powder (commercially available from China Aviation Mytek Additive Technology (Beijing) Co., Ltd., containing hydroxyl on the surface, particle size range 15-45 μm) in the powder supply cylinder, keeping the forming cylinder and powder supply cylinder temperature constant at 90°C; c) printing operation, spraying A component first, then B component according to the computer designed path, then the forming cylinder is lowered by one layer, the powder supply cylinder is raised by one layer, the powder is spread on the forming cylinder by the powder spreading roller, and A, B components are sprayed again, layer by layer, to obtain the uncured green body finally; d) placing the forming cylinder containing the green body in a 130°C oven for heating and curing for 3h, removing the excess powder, and obtaining the required green body; e) degreasing and sintering process (increasing from room temperature to 300°C at 3°C / min, keeping for 0.5h; then increasing to 600°C at 2°C / min, keeping for 2h to complete degreasing; then increasing to 1330°C at 4°C / min, keeping for 2h to complete sintering, and finally cooling to room temperature in the furnace), finally obtaining the required metal part.

[0084] After testing, the green body strength of the printed part is 8.19 MPa, the sintered part strength is 786 MPa, the sintered part density is 99.2%, and the sintered part hardness is 19HRC.

[0085] Example 3

[0086] Table 3 Example 3 Formula Table A component formula

[0087]

[0088] B component formula

[0089]

[0090] According to the above A component formula, the following operations are performed:

[0091] S1, sodium hydroxide is prepared into a 10% aqueous solution as a pH adjuster for standby;

[0092] S2, the double reactive monomer N-β-(aminoethyl)-γ-aminopropyl triethoxysilane is added to a mixed solvent of water and ethanol and stirred for standby;

[0093] S3, the pH adjuster in S1 is added dropwise to the S2 system while stirring, and the pH value is adjusted to 10;

[0094] S4, the stabilizer ethylene glycol is added to the S3 system while stirring, and the stirring is continued for 30-60 minutes until the solution becomes completely transparent and the hydrolysis is completed, and the printing can be performed.

[0095] The viscosity and surface tension of the prepared A component were tested at room temperature (25°C), and the viscosity of the adhesive was 2.19 mPa·s, and the surface tension was 27.75 mN·m -1 .

[0096] The following operations were performed according to the above component B formula:

[0097] X1, the epoxy resin was placed in a mixed solution of diluent ethylene glycol methyl ether, ethyl acetate and ethanol, and mechanically stirred until the epoxy resin was completely dissolved;

[0098] X2, to the mixture after X1 was uniformly mixed, polyethylene glycol 200, polyether modified organosiloxane was added while mechanically stirring.

[0099] X3, to the mixture of X2, latent curing agent 3-phenyl-1,1-dimethyl urea, N,N'-(4-methyl-1,3-phenylene) bis(N',N'-dimethyl urea) was added while stirring, mechanically stirred for 30 min, ultrasonic, filtration, to obtain a transparent and uniform adhesive.

[0100] The viscosity and surface tension of the prepared B component were tested at room temperature (25°C), and the viscosity of the adhesive was 4.14 mPa·s, and the surface tension was 38.69 mN·m -1 .

[0101] The use method of the adhesive is as follows: a) introducing the required printing model on the metal 3DP equipment; b) adding the prepared A and B components into the A and B ink storage tanks respectively, and placing 420 stainless steel powder (commercially available from Jiangsu Weilali New Material Technology Co., Ltd., with hydroxyl groups on the surface and a particle size range of 6-25 μm) in the powder supply cylinder, keeping the temperature of the forming cylinder and the powder supply cylinder constant at 90°C; c) printing operation, every layer of powder, the nozzle sprays A component first, then B component according to the computer designed path, then the forming cylinder is lowered by one layer, the powder supply cylinder is raised by one layer, the powder is spread on the forming cylinder by the powder spreading roller, and A and B components are sprayed in turn, layer by layer, to obtain the uncured green body finally; d) placing the forming cylinder containing the green body in a 130°C oven for 3h heating and curing, removing the excess powder, and obtaining the required green body; e) performing the debinding and sintering process (increasing from room temperature to 300°C at a rate of 3°C / min, keeping for 0.5h; then increasing to 600°C at a rate of 2°C / min, keeping for 1h to complete debinding; then increasing to 1390°C at a rate of 4°C / min, keeping for 2h to complete sintering, and finally cooling to room temperature with the furnace), to obtain the required metal part finally.

[0102] After testing, the strength of the printed green body was 4.52 MPa, the strength of the sintered part was 386 MPa, the density of the sintered part was 96.3%, and the hardness of the sintered part was 15HRC.

[0103] Example 4

[0104] Table 4 Formulation of Group A components

[0105]

[0106] Formulation of Group B components

[0107]

[0108] According to the above Group A component formulation, the following operations are performed:

[0109] S1, citric acid is prepared into a 10% aqueous solution as a pH regulator for standby;

[0110] S2, the double reactive monomer γ-glycidoxypropyltrimethoxysilane is added to the mixed solvent of water and ethanol and stirred for standby;

[0111] S3, the pH regulator in S1 is added dropwise to the S2 system while stirring, and the pH value is adjusted to 5;

[0112] S4, the stabilizer glycerol is added to the S3 system while stirring, and the stirring is continued for 30-60 minutes until the solution becomes completely transparent and the hydrolysis is completed, and the printing can be performed on the machine.

[0113] The viscosity and surface tension of the above prepared Group A component are tested at room temperature (25°C), and the viscosity of the adhesive is measured to be 1.86 mPa·s, and the surface tension is 32.73 mN·m -1 .

[0114] According to the above Group B component formulation, the following operations are performed:

[0115] X1, the epoxy resin is placed in a mixed solution of diluent ethylene glycol methyl ether and isopentyl acetate and mechanically stirred to dissolve the epoxy resin completely;

[0116] X2, 1,2-propanediol, polyethylene glycol 200, and alkyl-modified organosiloxane are added to the mixture after X1 is uniformly mixed while mechanically stirring;

[0117] X3, the latent curing agent N-[4-(4-methoxyphenoxy)phenyl]-N,N-dimethylurea is added to the X2 mixture while stirring, and mechanically stirred for 30 min, ultrasonic, and filtered to obtain a transparent and uniform adhesive.

[0118] The viscosity and surface tension of the above prepared Group B component are tested at room temperature (25°C), and the viscosity of the adhesive is measured to be 4.85 mPa·s, and the surface tension is 44.53 mN·m -1 .

[0119] The binder using method is: a) introducing the required printing model on the metal 3DP equipment; b) adding the prepared A, B components into A, B ink storage tanks respectively, and mechanically mixing the two kinds of zirconia powders (D 50 (77μm):D 50 (19μm)=6:1(m / m), commercially available from Jiaozuo Zhongcheng New Material Co., Ltd., containing hydroxyl groups on the surface) after mechanical mixing, and placing in the powder supply cylinder, keeping the forming cylinder and powder supply cylinder temperature constant at 95℃; c) printing operation, spraying A component first, then B component according to the computer designed path, then the forming cylinder is lowered by one layer, the powder supply cylinder is raised by one layer, the powder is spread on the forming cylinder by the powder spreading roller, and A, B components are sprayed again in sequence, layer by layer, to obtain the uncured green body finally; d) placing the forming cylinder containing the green body in a 150℃ oven for heating and curing for 1h, removing the excess powder, and obtaining the required green body. e) degreasing and sintering process (increasing from room temperature to 300℃ at 3℃ / min, keeping for 0.5h; then increasing to 600℃ at 2℃ / min, keeping for 1h to complete degreasing; then increasing to 1600℃ at 4℃ / min, keeping for 2h to complete sintering, and finally cooling to room temperature in the furnace), to finally obtain the required ceramic product.

[0120] The green body strength of the printed product is 4.87MPa, the sintered product strength is 63MPa, and the sintered product density is 60.7%.

[0121] Example 5

[0122] Table 5 Example 5 Formula Table A component formula

[0123] Ingredient Name Mass percent / % Bireactive monomer Gamma-aminopropyltriethoxysilane 3 Dilution solvent Water 13.85 Dilution solvent Ethanol 83 Stabilizer Ethylene glycol 0.15

[0124] B component formula

[0125]

[0126] The following operations are performed according to the above table A component formula:

[0127] S1, sodium hydroxide is prepared into a 10% aqueous solution as a pH adjuster for standby;

[0128] S2, the double reactive monomer γ-aminopropyl triethoxysilane is added to a mixed solvent of water and ethanol and stirred for standby;

[0129] S3, the pH adjuster in S1 is added dropwise to the S2 system while stirring, and the pH value is adjusted to 10;

[0130] S4, the stabilizer ethylene glycol is added to the S3 system while stirring, and the stirring is continued for 30-60 minutes until the solution becomes completely transparent and the hydrolysis is completed, and the printing on machine can be performed.

[0131] The viscosity and surface tension of the prepared A component were tested at room temperature (25°C), and the viscosity of the adhesive was 1.96 mPa·s, and the surface tension was 24.57 mN·m -1 .

[0132] The following operations were performed according to the above component B formula:

[0133] X1, the epoxy resin was placed in a mixed solution of diluent ethylene glycol butyl ether, ethanol and isoamyl acetate, and mechanically stirred until the epoxy resin was completely dissolved;

[0134] X2, to the mixture after X1 was uniformly mixed, polyethylene glycol 400 and polydimethylsiloxane were added while mechanically stirring;

[0135] X3, to the mixture of X2, latent curing agent toluene-2,4-di(N,N-dimethylaminopropyl urea) was added while stirring, mechanically stirred for 30 min, ultrasonic, filtration, and a transparent and uniform adhesive was prepared.

[0136] The viscosity and surface tension of the prepared B component were tested at room temperature (25°C), and the viscosity of the adhesive was 4.22 mPa·s, and the surface tension was 43.27 mN·m -1 .

[0137] The use method of the adhesive is as follows: a) introducing the required printing model on the metal 3DP equipment; b) adding the prepared A and B components to the A and B ink storage tanks respectively, and mechanically mixing the two kinds of alumina ceramic powder (D 50 (70 μm):D 50 (3 μm) = 3:1 (m / m), commercially available from Zhengzhou Yufa High-tech Material Co., Ltd., and containing hydroxyl groups on the surface) was placed in the powder supply cylinder after being uniformly mixed, and the temperature of the forming cylinder and the powder supply cylinder was kept constant at 80°C; c) printing operation was performed, and every time a layer of powder was laid, the nozzle sprayed A component first, then B component according to the computer designed path, then the forming cylinder was lowered by one layer, the powder supply cylinder was raised by one layer, the powder was laid on the forming cylinder by the powder laying roller, and A and B components were sprayed in sequence, layer by layer, to finally obtain a non-cured green body; d) the forming cylinder containing the green body was placed in a 140°C oven for heating and curing for 2 h, and the excess powder was removed to obtain the required green body; e) the green body was subjected to a debinding and sintering process (from room temperature to 300°C at a rate of 3°C / min, holding for 0.5 h; then from 300°C to 600°C at a rate of 2°C / min, holding for 1 h to complete debinding; then from 600°C to 1100°C at a rate of 5°C / min, and from 1100°C to 1500°C at a rate of 3°C / min, holding for 2 h to complete sintering, and finally cooling to room temperature in the furnace), and finally the required ceramic part was obtained.

[0138] The strength of the green part is 5.49 MPa, the strength of the sintered part is 66.7 MPa, and the density of the sintered part is 54.8%.

Claims

1. An ultra-low viscosity binder for use in a three-dimensional jetting molding process, characterized in that, The adhesive comprises independent A component and B component, the A component is reinforcing agent, and the B component is adhesive; The A component formula is shown in the following table The B component adhesive formula is shown in the following table The preparation method of the A component reinforcing agent comprises the following steps: S1, preparing a 10% pH regulator aqueous solution for standby, the pH regulator is acid or alkali; S2, adding the double reactive monomer into the diluent and stirring for standby; S3, adding the pH regulator in S1 into the system in S2 while stirring, and adjusting the pH value to be acidic or alkaline; S4, adding the stabilizer into the system in S3 while stirring, and continuously stirring for 30-60 minutes until the solution becomes completely transparent and the hydrolysis is completed, and then printing can be performed; The preparation method of the B component adhesive comprises the following steps: X1, mechanically stirring the base material in the diluent until the base material is completely dissolved; X2, adding the anti-jet plug agent and the surface tension regulator into the mixture in X1 while mechanically stirring; X3, adding the latent curing agent into the mixture in X2 while stirring, and mechanically stirring for 30 minutes, and then performing ultrasonic treatment and filtration to obtain the transparent and uniform adhesive.

2. The binder as claimed in claim 1, characterized in that Regarding the preparation of the A component, when the double reactive monomer is 3-aminopropyltrimethoxysilane or γ-glycidoxypropyltrimethoxysilane, the pH value is adjusted to be acidic in S3, and the pH value is 3-6; when the double reactive monomer is N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane or γ-aminopropyltriethoxysilane, the pH value is adjusted to be alkaline in S3, and the pH value is 8-11.

3. The use of the adhesive according to claim 1 in a three-dimensional jet molding process.

4. Use according to claim 3, characterized in that, After the A and B components of the adhesive are printed, a layer of powder containing hydroxyl groups is sprayed, and then a layer of the A component is sprayed, followed by a layer of the B component, and then the powder-A component-B component are sprayed multiple times, and the powder temperature in the molding bin is maintained in the range of 80-110°C, so that the silicon hydroxyl groups of the A component and the hydroxyl groups on the surface of the powder are dehydrated and condensed to form chemical bonds, and after the printing of the entire part is completed, the entire molding bin is heated at a temperature of 130-150°C for 1-3 hours, so that the B adhesive is cured, and at the same time, the amino groups of the A component and the epoxy groups of the B component are bonded to form "molecular bridges" between the powder and the epoxy adhesive, thereby increasing the bonding strength of the epoxy to the powder, and finally obtaining a high-strength green part.

5. The use according to claim 4, wherein the powder is metal powder, alumina or zirconia ceramic powder.

6. The use according to claim 4, wherein after the entire part is cured, a debinding and sintering process is performed.

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