WO2017036316A1

WO2017036316A1 - Inorganic composite phosphate binder for 3d sand printing, and preparation method thereof

Info

Publication number: WO2017036316A1
Application number: PCT/CN2016/096039
Authority: WO
Inventors: 邢金龙; 韩文
Original assignee: 宁夏共享化工有限公司
Priority date: 2015-08-31
Filing date: 2016-08-19
Publication date: 2017-03-09
Also published as: CN105127361B; CN105127361A

Abstract

Disclosed are an inorganic composite phosphate binder for 3D sand printing, and a preparation method thereof, the inorganic composite phosphate binder for 3D sand printing comprising the following components: aluminum hydroxide, magnesium carbonate, boric acid, 85% industrial grade phosphoric acid, urea, xylitol, D-sorbitol, citric acid, aluminum tripolyphosphate, aluminum dihydrogen tripolyphosphate, and deionized water. The components expressed in percentage by mass are respectively: 4.5%-9.5% of aluminum hydroxide, 1%-4% of magnesium carbonate, 2.5%-6.5% of boric acid, 30%-70% of 85% industrial grade phosphoric acid, 0.5%-1.5% of urea, 1%-3% of xylitol, 1%-3% of D-sorbitol, 0.5%-1.5% of citric acid, 1.5%-6.5% of aluminum tripolyphosphate, 1.5%-6.5% of aluminum dihydrogen tripolyphosphate, and 7%-37% of deionized water. The inorganic composite phosphate binder obtained from the preparation method has a low viscosity and a high binding strength. The binder has a low residual strength and an improved collapsibility after being baked at a high temperature of 600°C or above, and also has an improved resistance to moisture absorption.

Description

Composite phosphate inorganic binder for 3D sand printing and preparation method thereof

[0001] The present invention belongs to the field of casting auxiliary materials, and particularly relates to a composite phosphate inorganic binder for 3D sand printing and a preparation method thereof.

Background technique

[0002] Three Dimensional Printing (3DP) was proposed by E. Sachs et al. in 1992. According to the principle of an inkjet printer, droplets of material are ejected from nozzles and solidified layer by layer in a certain path.

[0003] 3D printing technology together with robots and the Internet is known as the main symbol of the third industrial revolution. Currently

Some industrial grade 3D printers have been used in foundry production services, mainly for rapid prototyping of castings, turning molds, printing molds, sand cores, etc.

[0004] At present, developed countries such as Germany and Japan have widely applied 3D printing technology to the foundry industry. In China, 3D printing technology is in its infancy, especially in the foundry industry. There are very few companies that use 3D sand printing technology to manufacture high-end precision non-ferrous metal castings.

[0005] The binder for 3D sand printing commonly used by casting companies at home and abroad is an organic resin, such as phenolic resin.

. Although the organic resin binder has excellent performance, its high cost, serious environmental pollution of the resin sand during use, and limitations in the quality control of the casting, severely restricts the stickiness of the organic resin. Further development of the knot. In order to cater to the concept of “green casting” with high efficiency, energy saving and environmental protection, it has become a consensus of foundry workers to develop an inorganic binder for 3D sand printing with performance equivalent to organic resin and environmental protection.

technical problem

[0006] In the post-Soviet period, foundry workers tried to apply phosphate inorganic binders to the field of casting, but because they can only be hardened by heating, plus common phosphate inorganic binders There are problems such as high viscosity, low strength, poor collapsibility and poor moisture absorption resistance, which seriously restricts its application in the fields of traditional cast steel and cast iron, and further restricts its application in high-tech casting technology such as 3D sand printing.

[0007] 3D sand printing technology requires low viscosity of the binder and can achieve rapid hardening, while ensuring short sputum The strength of the sand in the room increases, and the ordinary phosphate inorganic binder can not meet the demand of 3D sand printing, which directly hinders the application of phosphate inorganic binder in the high-end casting field.

Problem solution

Technical solution

[0008] In view of the deficiencies of the prior art, the present invention provides a composite phosphate inorganic binder for 3D sand printing and a preparation method thereof, and the prepared composite phosphate inorganic binder for 3D sand printing has high strength and viscosity. Low, can be used in a short period of time and can achieve fast hardening, good moisture absorption and excellent collapsing performance.

[0009] In order to solve the problems existing in the prior art, the present invention provides the following technical solutions:

[0010] A composite phosphate inorganic binder for 3D sand printing, comprising the following components: aluminum hydroxide, magnesium carbonate, boric acid, 85% industrial phosphoric acid, urea, xylitol, D-sorbitol, citric acid, Aluminum tripolyphosphate, aluminum dihydrogen phosphate, deionized water, wherein the mass percentage ratio of each component is: aluminum hydroxide 4.5%-9.5% ^ magnesium carbonate ^. ^^, Boric acid ^^^^^, 85% industrial phosphoric acid SO^ Oy^ Urea 0.5<3⁄4-1. 5<3⁄4, Xylitol ld D-sorbitol l^^y^ Citric acid O.SH.Sy^ Aluminum tripolyphosphate 1.5<3⁄4-6.5 %, aluminum dihydrogen phosphate 1.5<3⁄4-6.5<3⁄4, deionized water ^? ^ ;

[0011] The magnesium carbonate is reacted with phosphate as a modifier to form a non-water-soluble three-dimensional network structure MgHP 04 xH20, and water molecules are not easily invaded therein, thereby improving the moisture absorption resistance of the molding sand;

[0012] The B 3+ is added as a modifier to an aqueous solution of an acid aluminum phosphate, reacts with phosphoric acid to form boron phosphate, and the same can also react with a polyhydroxy Al(OH) ₃ to form an aluminum hydroxide complex boric acid. The salt, the above two substances formed can enhance the bonding strength of the binder, and the stability of the aqueous solution of the aluminum phosphate is also enhanced;

[0013] The Mg ² +, a small ionic radius, and the compound of prices, have a strong influence on the adjacent -0-H bonds, Shaw provoke -0-H bond H ₂ 0 molecular interaction, such improved humidity resistance;

[0014] The aluminum tripolyphosphate and the aluminum tripolyphosphate as a modifier increase the content of the dialuminum phosphate in the phosphate binder system, and the diammonium phosphate reacts as a latent curing agent. The main chemical composition, the increase in its content, can improve the curing speed and bond strength of the adhesive;

[0015] The citric acid and urea act as modifiers to reduce the neutralization degree of the composite phosphate inorganic binder, thereby enhancing the stability of the binder system; meanwhile, the addition of citric acid and urea improves the phosphate viscosity The collapsibility of the binder sand;

[0016] The xylitol and D-sorbitol as modifiers improve the moisture absorption resistance of the phosphate binder system, Xylitol and D-sorbitol also improve the collapsibility of the phosphate binder.

[0017] In the same manner, the present invention provides a method for preparing a composite phosphate inorganic binder for 3D sand printing, which comprises the following steps:

[0018] Step one, adding aluminum hydroxide and deionized water to the reaction vessel, stirring and heating to a slightly boiling state;

[0019] Step 2, slowly add 85% industrial phosphoric acid, after the reaction to clear and transparent, continue the reaction for at least 1 h, turn off the heating, after the temperature is lowered to 60 ° C, slowly add magnesium carbonate, and keep the reaction at 60 ° C for at least 30 min. , heating to a slightly boiling state;

[0020] Step three, slowly add boric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 30min, sequentially add aluminum tripolyphosphate and aluminum tripolyphosphate, after the reaction to clear and transparent, continue to stir the reaction for at least 30min;

[0021] Step 4, sequentially adding urea, xylitol, D-sorbitol and citric acid slowly, after the reaction to clear and transparent, continue to stir the reaction for at least 1 h, to obtain a new 3D sand type composite phosphate inorganic binder for printing, to be After the temperature of the system is lowered to room temperature, it is detected and packaged.

Advantageous effects of the invention

Beneficial effect

[0022] The beneficial effects of the technical solution of the present invention are as follows: The prepared composite phosphate inorganic binder has a viscosity of 25 ° C and a viscosity of less than 15 mPa· _s , and the viscosity is low; the composite phosphate inorganic binder is added in an amount of 4.5. % (% of the standard sand), the amount of curing agent added is 30% (accounting for the specific gravity of the binder) 吋, the standard sand test block of <D30mm*50mm has a compressive strength at room temperature greater than 6.0Mpa, and the bond strength is high; After baking at a high temperature of 600 ° C or higher, the residual strength is low. When the baking temperature exceeds 800 ° C, the residual strength is less than 0.5 Mpa, indicating that the binder has excellent collapse properties, and is used in the field of casting, castings are clear. The sand is easy; the standard sand test block of the composite phosphate inorganic binder has a compressive strength reduction rate of only about 6.5% after being stored for 24 hours in an environment with an air humidity of more than 80%, indicating that the adhesive has excellent moisture absorption resistance. The utility model overcomes the shortcomings of the traditional phosphate inorganic binder against poor hygroscopicity, and prolongs the storage and use of the molding sand; the composite phosphate inorganic binder can be used for 5 min ≤ t ≤ 15 min, and the standard sand test block is 30min left after the modeling is completed You can mold. It can be used shortly in the daytime, can achieve rapid hardening, and meets the requirements of sand-type inkjet printing; the composite phosphate inorganic binder is a green material compared with the organic resin binder, during production and use. It will not pollute the environment. Embodiments of the invention

[0023] In order to make those skilled in the art better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to specific embodiments.

[0024] Embodiment 1

[0025] The constituent raw materials of the composite phosphate inorganic binder for 3D sand printing of the present embodiment are:

Aluminum hydroxide 6.5%, magnesium carbonate 3%, boric acid 3%, 85% industrial phosphoric acid 50%, urea 1<3⁄4, xylitol 2%, D-sorbitol 2%, citric acid 1%, aluminum tripolyphosphate 2.5 %, 4% aluminum dihydrogen phosphate, 2 5 < 3⁄4 deionized water.

[0026] A method for preparing a composite phosphate non-binder binder for 3D sand printing in this embodiment is as follows:

[0027] Step one, adding 65Kg of aluminum hydroxide and 250Kg of deionized water to the enamel reactor, stirring and heating to a slightly boiling state;

[0028] Step two, slowly add 500kg

85% industrial phosphoric acid, after the reaction to clear and transparent, continue to react for at least lh, turn off the heating, wait for the temperature to drop

After 60 ° C, 30 Kg of magnesium carbonate was slowly added, and the reaction was kept at 60 ° C for at least 30 min, and then heated to a slightly boiling state;

[0029] Step three, slowly add 30Kg of boric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 30min, sequentially add 25Kg of aluminum tripolyphosphate and 40Kg of aluminum dihydrogen phosphate, after the reaction to clear and transparent, continue to stir the reaction At least 30min;

[0030] Step 4, sequentially adding 10Kg urea, 20Kg xylitol, 20Kg D-sorbitol and 10Kg citric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 1h, to obtain a new type of 3D sand type composite phosphate inorganic Binder, after the temperature of the system drops to room temperature, it is tested and packaged.

[0031] The new composite phosphate inorganic binder has a viscosity at 14 ° C of 14 mpa. _S; can be used for 5 min ≤ t ≤

15min _{; the} addition amount is 4.5% (accounting for the specific gravity of the standard sand), and the O30mm*50mm standard sand test block has a compressive strength of 6.62Mpa at room temperature; the standard sand test block is baked at 800 °C. The residual strength is 0.42Mpa; after the standard sand test block is stored in an environment with an air humidity of 80% for 24 hours, the compressive strength reduction rate is 6.2%. [0032] Embodiment 2

[0033] The constituent raw materials of the composite phosphate inorganic binder for 3D sand printing of the present embodiment are: 7% aluminum hydroxide, 3% magnesium carbonate, 4.5% boric acid, 85% industrial phosphoric acid 47%, urea 1 <3⁄4, Xylitol 1.5%, D-sorbitol 1.5%, citric acid 1%, aluminum tripolyphosphate 3%, aluminum dihydrogen phosphate 3%, deionized water 27.5%.

[0034] A preparation method of a composite phosphate non-binder binder for 3D sand printing in this embodiment is as follows:

[0035] Step one, 70Kg of aluminum hydroxide and 275Kg of deionized water are added to the enamel reactor, stirred and heated to a slightly boiling state;

[0036] Step two, slowly add 470kg

85% industrial phosphoric acid, after the reaction to clear and transparent, continue to react for at least 1 h, turn off the heating, after the temperature drops to 60 ° C, slowly add 30Kg of magnesium carbonate, keep the reaction at 60 ° C for at least 30min, then heat to slightly boiling State

[0037] Step three, slowly add 45Kg of boric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 30min, sequentially add 30Kg of aluminum tripolyphosphate and 30Kg of aluminum dihydrogen phosphate, after the reaction to clear and transparent, continue to stir the reaction At least 30min;

[0038] Step 4, sequentially adding 10Kg urea, 15Kg xylitol, 15Kg D-sorbitol and 10Kg citric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 1h, to obtain a new 3D sand type composite phosphate phosphate inorganic paste The mixture is tested and packaged after the temperature of the system is lowered to room temperature.

[0039] The novel composite inorganic phosphate binder at 25 ° C viscosity inch 12mpa _S;. Inches may be used between 5min≤t≤ _15min; added in an amount of 4.5% (by proportion of standard sand) inch day which O30mm*50mm standard sand test block 2 4h normal temperature compressive strength is 6.45Mpa; its standard sand test block after 800 °C high temperature baking, the residual strength is 0.39Mpa; its standard sand test block in air humidity is 80% After 24 hours of storage in the environment, the compressive strength reduction rate was 6.4%.

[0040] Embodiment 3

[0041] The constituent raw materials of the composite phosphate inorganic binder for 3D sand printing of the present embodiment are: 9% aluminum hydroxide, 4% magnesium carbonate, 6% boric acid, 85% industrial phosphoric acid 45%, urea 1.5%, wood Sugar alcohol 2<3⁄4, D-sorbitol 2, 1.5% citric acid, 3% aluminum tripolyphosphate, 6% aluminum dihydrogen phosphate, and 17% deionized water.

[0042] The preparation method of the composite phosphate non-binder binder for 3D sand printing in this embodiment is as follows:

[0043] Step one, adding 90Kg of aluminum hydroxide and 170Kg of deionized water to the enamel reactor, stirring and stirring Heating to a slightly boiling state;

[0044] Step two, slowly adding 450kg

85% industrial phosphoric acid, after the reaction to clear and transparent, continue to react for at least 1 h, turn off the heating, after the temperature drops to 60 ° C, slowly add 40Kg of magnesium carbonate, keep the reaction at 60 ° C for at least 30min, then heat to slightly boiling State

[0045] Step 3, slowly adding 60Kg of boric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 30min, sequentially add 60Kg of aluminum tripolyphosphate and 60Kg of aluminum dihydrogen phosphate, after the reaction to clear and transparent, continue to stir the reaction At least 30min;

[0046] Step four, slowly add 15Kg urea, 20Kg xylitol, 20Kg D-sorbitol and 15Kg citric acid slowly, after the reaction to clear and transparent, continue to stir the reaction for at least 1h, to obtain a new type of 3D sand type composite phosphate inorganic Binder, after the temperature of the system drops to room temperature, it is tested and packaged.

[0047] The new composite phosphate inorganic binder has a viscosity at 13 ° C of 13 mPa. _S; can be used for 5 min ≤ t ≤ 15 min _{; the} amount of addition is 4.5% (% of the standard sand), O30mm*50mm standard sand test block 2 4h normal temperature compressive strength is 6.57Mpa; after the standard sand test block is baked at 800°C, the residual strength is 0.44Mpa; the standard sand test block is 80% in air humidity. After 24 hours of storage in the environment, the compressive strength reduction rate was 6.6%.

[0048] Embodiment 4

[0049] The constituent raw materials of the composite phosphate inorganic binder for 3D sand printing of the present embodiment are: 7% aluminum hydroxide, 2.5% magnesium carbonate, 4.5% boric acid, 85% industrial phosphoric acid 50%, urea 1<3⁄4, Xylitol 2<3⁄4, D-sorbitol 2%. Citric acid 1%, aluminum tripolyphosphate 4%, aluminum dihydrogen phosphate 4%, deionized water 22%.

[0050] A preparation method of a composite phosphate non-binder binder for 3D sand printing in this embodiment is as follows:

[0051] Step one, 70Kg of aluminum hydroxide and 220Kg of deionized water are added to the enamel reactor, stirred and heated to a slightly boiling state;

[0052] Step two, slowly add 500kg

85% industrial phosphoric acid, after the reaction to clear and transparent, continue to react for at least 1h, turn off the heating, after the temperature drops to 60 ° C, slowly add 25Kg magnesium carbonate, keep the reaction at 60 ° C for at least 30min, then heat to slightly boiling State

[0053] Step three, slowly add 45Kg of boric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 30min , 40Kg of aluminum tripolyphosphate and 40Kg of aluminum dihydrogen phosphate are added in sequence, and after the reaction is clear and transparent, the stirring reaction is continued for at least 30 minutes;

[0054] Step 4, sequentially adding 10Kg urea, 20Kg xylitol, 20Kg D-sorbitol and 10Kg citric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 1h, to obtain a new 3D sand type composite phosphate inorganic Binder, after the temperature of the system drops to room temperature, it is tested and packaged.

[0055] The novel composite inorganic phosphate binder at 25 ° C viscosity inch 13mpa _S;. Inches may be used between 5min≤t≤ _15min; added in an amount of 4.5% (by proportion of standard sand) inch day which O30mm*50mm standard sand test block 2 4h normal temperature compressive strength is 6.22Mpa; its standard sand test block after 800 °C high temperature baking, residual strength is 0.37Mpa; its standard sand test block in air humidity is 80% After 24 hours of storage in the environment, the compressive strength reduction rate was 5.97%.

[0056] Embodiment 5

[0057] The constituent raw materials of the composite phosphate inorganic binder for 3D sand printing of the present embodiment are: 5% aluminum hydroxide, 2% magnesium carbonate, 4% boric acid, 85% industrial phosphoric acid 55%, urea 1%, wood Sugar alcohol 2.5%, D-sorbitol 2.5%, citric acid 1.5%, aluminum tripolyphosphate 2%, aluminum dihydrogen phosphate 2%, deionized water 22.5%.

[0058] A preparation method of a composite phosphate non-binder binder for 3D sand printing in this embodiment is as follows:

[0059] Step one, adding 50Kg of aluminum hydroxide and 225Kg of deionized water to the enamel reactor, stirring and heating to a slightly boiling state;

[0060] Step two, slowly add 550kg

85% industrial phosphoric acid, after the reaction to clear and transparent, continue to react for at least 1 h, turn off the heating, after the temperature drops to 60 ° C, slowly add 20Kg of magnesium carbonate, keep the reaction at 60 ° C for at least 30min, then heat to slightly boiling State

[0061] Step three, slowly add 40Kg of boric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 30min

Then, 20Kg of aluminum tripolyphosphate and 20Kg of aluminum dihydrogenphosphate were sequentially added, and after reacting until clear and transparent, the reaction was continuously stirred for at least 30 minutes.

[0062] Step 4, slowly adding 10Kg urea, 25Kg xylitol, 25Kg D-sorbitol and 15Kg citric acid

After the reaction is clear and transparent, continue to stir the reaction for at least lh to obtain a new composite phosphoric acid inorganic binder for 3D sand printing, which is tested and packaged after the temperature of the system is lowered to room temperature.

[0063] The new composite phosphate inorganic binder has a viscosity of 13 mPa at 25 ° C _{; S} can be used for 5 min ≤ t ≤ 15min _{; the} amount of addition is 4.5% (accounting for the specific gravity of the standard sand), the standard sand test block of O30mm*50mm is the current temperature compressive strength of 6.39Mpa; the standard sand test block is baked at 800 °C. The residual strength is 0.41Mpa; after the standard sand test block is stored in an environment with an air humidity of 80% for 24 hours, the compressive strength reduction rate is 6.1%.

Industrial applicability

The above is a preferred embodiment of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit of the invention, and such obvious alternatives are within the scope of the invention.

Claims

Claim

A composite phosphate inorganic binder for 3D sand printing, comprising the following components: aluminum hydroxide, magnesium carbonate, boric acid, 85% industrial phosphoric acid, urea, xylitol, D-sorbitol, citric acid , aluminum tripolyphosphate, aluminum dihydrogen phosphate, deionized water, wherein the mass percentage ratio of each component is: aluminum hydroxide

4.5%-9.5<3⁄4, magnesium carbonate 1%-4%, IIIf2.5%-6.5%^ 85% industrial phosphoric acid SO^^Oy^3⁄40.5%-1.5%^ Xylose Ill%-3%^ D- Sorbitol ^ ^, citric acid O.SH.Sy^ aluminum tripolyphosphate 1.5<3⁄4-6. 5<3⁄4, aluminum dihydrogen phosphate l ^^^y^ Deionized water 7<3⁄4-37<3⁄4.

The composite phosphate inorganic binder for 3D sand printing according to claim 1, wherein the magnesium carbonate is used as a modifier to react with phosphate to form a non-water-soluble three-dimensional network structure MgHP04'. xH20, water molecules are not easy to invade, improving the moisture absorption resistance of the molding sand.

The composite phosphate inorganic binder for 3D sand printing according to claim 1, wherein the B 3+ is added as a modifier to an aqueous solution of an aluminum phosphate, and reacts with phosphoric acid to form boron phosphate. The same can also react with polyhydroxy Al(OH) ₃ to form aluminum hydroxide complex borate, and the above two substances can enhance the bonding strength of the binder, and also make the aqueous solution of aluminum phosphate. The stability is enhanced.

The composite phosphate inorganic binder for 3D sand printing according to claim 1, wherein the Mg ² + has a small ionic radius and a high valence, and is strong against an adjacent -0-H bond. Effect, Xiao Wei-0-H bond and H ₂ 0 molecule action, making anti-hygroscopicity

[Claim 5] The composite phosphate inorganic binder for 3D sand printing according to claim 1, wherein the aluminum tripolyphosphate and the aluminum tripolyphosphate are used as modifiers to increase phosphoric acid The content of dialuminum phosphate in the salt binder system, the main chemical component of the reaction of the aluminum dihydrogen phosphate as a latent and curing agent, the increase of the content can improve the curing speed and bonding strength of the binder.

[Claim 6] A composite phosphate inorganic binder for 3D sand printing according to claim 1, wherein the citric acid and urea act as modifiers to reduce inorganic phosphate inorganic bonding The degree of neutralization of the agent enhances the stability of the binder system; meanwhile, the addition of citric acid and urea improves the collapsibility of the phosphate binder sand.

[Claim 7] A composite phosphate inorganic binder for 3D sand printing according to claim 1, wherein the xylitol and D-sorbitol are used as modifiers to improve phosphate binder The anti-hygroscopic properties of the system, together with xylitol and D-sorbitol, also improve the collapsibility of the phosphate binder.

[Claim 8] A method for preparing a composite phosphate inorganic binder for 3D sand printing, characterized in that

, including the following steps:

Step one, adding aluminum hydroxide and deionized water to the reaction vessel, stirring and heating to a slightly boiling state;

Step 2, slowly add 85% industrial phosphoric acid, after the reaction to clear and transparent, continue the reaction for at least 1 h, turn off the heating, after the temperature drops to 60 ° C, slowly add magnesium carbonate, keep the reaction at 60 ° C for at least 30 min, then heat To a slightly boiling state;

Step 3, slowly add boric acid, after the reaction to clear and transparent, continue to stir the reaction for at least 30 min, sequentially add aluminum tripolyphosphate and aluminum dihydrogen phosphate, after the reaction to clear and transparent, continue to stir the reaction for at least 30 min;

Step 4, slowly add urea, xylitol, D-sorbitol and citric acid slowly, after the reaction to clear and transparent, continue to stir the reaction for at least 1 h, to obtain a new 3D sand-type composite phosphate inorganic binder for printing, to be cooled by the system temperature Test and package after room temperature.