CN105057566A - Novel liquid curing agent used for 3D sand mold printing inorganic binder and preparation method of novel liquid curing agent - Google Patents

Abstract

The invention relates to a novel liquid curing agent for 3D sand printing inorganic binder and a preparation method thereof. The liquid curing agent includes diacetin, triacetin, absolute ethanol, methacrylic acid, vinyl acetate, wood sugar alcohol. The liquid curing agent for 3D sand printing inorganic binder has low viscosity, and can realize fast hardening, which meets the requirements of sand inkjet printing; the addition amount of the liquid curing agent for 3D sand printing inorganic binder is 20% Binder specific gravity), its Φ30mm×50mm standard sand test block room temperature compressive strength can reach more than 5.0MPa, high bonding strength; 3D sand printing inorganic binder liquid curing agent free acid content <1.0%, water content <0.5%, excellent performance; and in the process of production and use, it will not produce harmful substances and irritating odors to the human body and the environment, which belongs to green environmental protection materials.

Description

Novel liquid curing agent for 3D sand printing inorganic binder and preparation method thereof

technical field

The invention relates to the field of casting auxiliary materials, in particular to a novel liquid curing agent for inorganic binders for 3D sand mold printing and a preparation method thereof.

Background technique

Three-dimensional printing (ThreeDimensionalPrinting, 3DP) was proposed by E. Sachs et al. in 1992. Based on the principle of inkjet printers, material droplets are ejected from nozzles and solidified layer by layer according to a certain path.

Together with robots and the Internet, 3D printing technology is called the main symbol of the third industrial revolution. At present, some industrial-grade 3D printers have been used in foundry production services, mainly for rapid prototyping of castings, remaking molds, printing mold shells, sand cores, etc.

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

At present, the binders for 3D sand printing commonly used by foundry companies at home and abroad include organic resins and inorganic binders. Due to the monopoly of foreign technology, domestic foundry enterprises that introduce 3D printing technology can only rely on imports to obtain the required 3D sand printing binder and its supporting curing agent, which not only has to bear high costs, but also has certain risks. .

3D printing technology will definitely lead the reform and development of the entire foundry industry in the 21st century. Therefore, as China, which has the largest foundry industry in the world, the research and development of 3D sand printing binders and their supporting curing agents is an important task. Very promising and meaningful. At present, there are no liquid curing agent products for 3D sand printing inorganic binders in China, and the ordinary cast steel and cast iron fields do not have high requirements for the viscosity, free acid, moisture and other indicators of liquid curing agents for inorganic binders, which will lead to When the liquid curing agent for ordinary cast steel and cast iron is used in the field of 3D sand printing, its high viscosity cannot meet the requirements of inkjet printers. On the other hand, 3D sand printing requires rapid hardening, which must be achieved in a short period of time. Sufficient strength, while the free acid and moisture content of the liquid curing agent for ordinary cast steel and cast iron are high, the hardening speed is slow, and the strength growth is slow, which cannot meet the requirements of 3D sand printing. Therefore, in order to cater to the overall development trend of the foundry industry and break the monopoly of foreign technology, the present invention has developed a 3D sand printing inorganic bond with low viscosity, low free acid, low moisture, fast hardening and stable performance through technological innovation. Agent with a new type of liquid curing agent.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a new type of liquid curing agent for 3D sand printing inorganic binder and its preparation method, and obtains a low viscosity, low free acid, low moisture, capable of rapid hardening, Liquid curing agent for 3D sand printing inorganic binder with stable performance.

In order to solve the above technical problems, the present invention provides the following technical solutions:

A novel 3D sand printing inorganic binder liquid curing agent according to the present invention is characterized in that it comprises glyceryl diacetate, glyceryl triacetate, dehydrated alcohol, methacrylic acid, vinyl acetate, xylitol .

The percentages of each component are: 28-48% of glyceryl diacetate, 22%-38% of glyceryl triacetate, 3.5%-12.5% of absolute ethanol, 2%-6% of methacrylic acid, 9% of vinyl acetate %-25%, xylitol 2%-4%.

Wherein, the xylitol can stabilize the curing agent and improve the moisture resistance of the sand mold.

A method for preparing a liquid curing agent for a novel 3D sand printing inorganic binder, characterized in that it comprises the following steps:

Step 1, pump the diacetin and triacetin into the enamel reaction kettle with a vacuum pump, start stirring, and stir for more than 30 minutes;

Step 2, add vinyl acetate and continue to stir for more than 30 minutes;

Step 3: add absolute ethanol, methacrylic acid and xylitol in sequence, and continue stirring for more than 30 minutes to obtain a new liquid curing agent for inorganic binders for 3D sand printing, which is tested and packaged.

Further, the prepared liquid curing agent for 3D sand printing inorganic binder has a viscosity of <20mpa.s at 25°C; a usable time of 5min≤t≤15min, a free acid of <1.0%, and a water content of <0.5%.

The beneficial effects of the technical solution of the present invention are: the low-viscosity 3D sand printing inorganic binder liquid curing agent is obtained through the above method, which meets the use requirements of sand inkjet printing; it can realize rapid hardening and meet the requirements of sand printing. Ink printing use requirements; when the liquid curing agent for 3D sand printing inorganic binder is added at 20% (accounting for the proportion of the binder), the normal temperature compressive strength of the standard sand test block of Φ30mm*50mm can reach more than 5.0Mpa, High bonding strength; 3D sand printing inorganic binder liquid curing agent free acid <1.0%, water content <0.5%, excellent performance; and will not produce harmful substances and stimuli to the human body and the environment during production and use Non-toxic odor, belongs to green environmental protection materials.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with specific examples.

Implementation Case 1

The raw materials of the liquid curing agent for 3D sand printing inorganic binder in this example are: 36% glyceryl diacetate, 34% glycerol triacetate, 7.5% absolute ethanol, 3.5% methacrylic acid, and 16% vinyl acetate , Xylitol 3%.

The preparation method of the liquid curing agent for the 3D sand printing inorganic binder of this embodiment is:

Step 1, pump 360Kg glyceryl diacetate and 340Kg glycerol triacetate into the enamel reaction kettle with a vacuum pump, start stirring, and stir for more than 30 minutes;

Step 2, slowly add 160Kg vinyl acetate, and continue to stir for more than 30min;

Step 3: Add 75Kg of absolute ethanol, 35Kg of methacrylic acid and 30Kg of xylitol in sequence, and continue to stir for more than 30 minutes to obtain a new liquid curing agent for inorganic binders for 3D sand printing, testing and packaging.

The liquid curing agent for 3D sand printing inorganic binder has a viscosity of 16mpa.s at 25°C, a density of 1.16g/ml; a free acid of 0.8%; a water content of 0.45%; and a usable time of 5min≤t≤15min ; The appearance is colorless and transparent liquid; when the added amount is 20% (accounting for the proportion of the binder), the 24h normal temperature compressive strength of the standard sand test block of Φ30mm*50mm is 5.12Mpa.

Implementation Case 2

The raw materials of the liquid curing agent for 3D sand printing inorganic binder in this example are: 40% glyceryl diacetate, 32% glycerol triacetate, 9% absolute ethanol, 4.5% methacrylic acid, and 12% vinyl acetate , Xylitol 2.5%.

The preparation method of the liquid curing agent for the 3D sand printing inorganic binder of this embodiment is:

Step 1, pump 400Kg glyceryl diacetate and 320Kg glyceryl triacetate into the enamel reaction kettle with a vacuum pump, start stirring, and stir for more than 30 minutes;

Step 2, slowly add 120Kg vinyl acetate, and continue to stir for more than 30min;

Step 3: Add 90Kg of absolute ethanol, 45Kg of methacrylic acid and 25Kg of xylitol in sequence, and continue to stir for more than 30 minutes to obtain a new liquid curing agent for inorganic binders for 3D sand printing, testing and packaging.

The liquid curing agent for 3D sand printing inorganic binder has a viscosity of 18mpa.s at 25°C, a density of 1.11g/ml; a free acid of 0.75%; a water content of 0.42%; and a usable time of 5min≤t≤15min ; The appearance is colorless and transparent liquid; when the addition amount is 20% (accounting for the proportion of the binder), the 24h normal temperature compressive strength of the standard sand test block of Φ30mm*50mm is 5.26Mpa.

Implementation Case Three

The raw materials of the liquid curing agent for 3D sand printing inorganic binder in this embodiment are: glyceryl acetate 38%, glyceryl triacetate 30%, absolute ethanol 8%, methacrylic acid 4%, vinyl acetate 17%, Xylitol 3%.

Step 1, pump 380Kg glyceryl diacetate and 300Kg glycerol triacetate into the enamel reaction kettle with a vacuum pump, start stirring, and stir for more than 30 minutes;

Step 2, slowly add 170Kg vinyl acetate, and continue to stir for more than 30min;

Step 3: Add 80Kg of absolute ethanol, 40Kg of methacrylic acid and 30Kg of xylitol in sequence, and continue stirring for more than 30 minutes to obtain a liquid curing agent for inorganic binders for 3D sand printing, which is tested and packaged.

The liquid curing agent for 3D sand printing inorganic binder has a viscosity of 15mpa.s at 25°C, a density of 1.14g/ml; a free acid of 0.65%; a water content of 0.38%; and a usable time of 5min≤t≤15min ; The appearance is colorless and transparent liquid; when the addition amount is 20% (accounting for the proportion of the binder), the 24h normal temperature compressive strength of the standard sand test block of Φ30mm*50mm is 5.09Mpa.

Implementation Case 4

The raw materials of the liquid curing agent for 3D sand printing inorganic binder in this example are: 46% glyceryl diacetate, 27% glycerol triacetate, 5% absolute ethanol, 5.5% methacrylic acid, and 13% vinyl acetate , Xylitol 3.5%.

Step 1, pump 460Kg glyceryl diacetate and 270Kg glyceryl triacetate into the enamel reaction kettle with a vacuum pump, start stirring, and stir for more than 30 minutes;

Step 2, slowly add 130Kg vinyl acetate, and continue to stir for more than 30min;

Step 3: Add 50Kg of absolute ethanol, 55Kg of methacrylic acid and 35Kg of xylitol in sequence, and continue stirring for more than 30 minutes to obtain a new liquid curing agent for inorganic binders for 3D sand printing, which is tested and packaged.

The liquid curing agent for 3D sand printing inorganic binder has a viscosity of 17mpa.s at 25°C, a density of 1.09g/ml; a free acid of 0.68%; a water content of 0.40%; and a usable time of 5min≤t≤15min ; The appearance is colorless and transparent liquid; when the addition amount is 20% (accounting for the proportion of the binder), the 24h normal temperature compressive strength of the standard sand test block of Φ30mm*50mm is 5.21Mpa.

Implementation Case Five

The raw materials of the liquid curing agent for 3D sand printing inorganic binder in this example are: 42% glyceryl diacetate, 29% glycerol triacetate, 4% absolute ethanol, 3% methacrylic acid, and 20% vinyl acetate , Xylitol 2%.

Step 1, pump 420Kg glyceryl diacetate and 290Kg glycerol triacetate into the enamel reaction kettle with a vacuum pump, start stirring, and stir for more than 30 minutes;

Step 2, slowly add 200Kg vinyl acetate, and continue to stir for more than 30min;

Step 3: add 40Kg of absolute ethanol, 30Kg of methacrylic acid and 20Kg of xylitol in sequence, and continue to stir for more than 30 minutes to obtain a liquid curing agent for inorganic binders for 3D sand printing, which is tested and packaged.

The liquid curing agent for 3D sand printing inorganic binder has a viscosity of 15mpa.s at 25°C, a density of 1.07g/ml; a free acid of 0.71%; a water content of 0.49%; and a usable time of 5min≤t≤15min ; The appearance is colorless and transparent liquid; when the added amount is 20% (accounting for the proportion of the binder), the 24h normal temperature compressive strength of the standard sand test block of Φ30mm*50mm is 5.19Mpa.

In the new liquid curing agent for inorganic binders for 3D sand printing, glycerol triacetate, glycerol triacetate and vinyl acetate are the main components. acid. Then, the acid generated by the hydrolysis reaction and the methacrylic acid introduced into the system are ionized to generate H ⁺ . Due to the generation of a large amount of H ⁺ , the hydrolysis of the silicate in the binder is accelerated, and a large amount of silicic acid sol is generated. Silica sol can form a three-dimensional network structure, making the molding sand tightly bonded together.

Since the curing agent and binder will be accompanied by moisture during the reaction process, the presence of moisture will seriously affect the strength of the molding sand, so volatile anhydrous ethanol is introduced into the system to take away the curing agent and binder reaction moisture produced. As a polyol, xylitol is introduced into the curing agent system, which can stabilize the curing agent system. At the same time, as a macromolecular alcohol, it can also improve the moisture absorption resistance of the sand mold to a certain extent.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention are all Should be included within the protection scope of the present invention.

Claims (4)

1. novel 3D sand mold prints an inorganic binder liquid curing-agent, it is characterized in that, comprises two acetoglycerides, triacetyl glycerine, absolute ethyl alcohol, methacrylic acid, vinylacetate, xylitol; Wherein the percentage of each component is: two acetoglyceride 28-48%, triacetyl glycerine 22%-38%, absolute ethyl alcohol 3.5%-12.5%, methacrylic acid 2%-6%, vinylacetate 9%-25%, xylitol 2%-4%.

2. the novel 3D sand mold of one according to claim 1 prints inorganic binder liquid curing-agent, it is characterized in that, described xylitol can stabilizing and curing agent, improves the moisture resistance of sand mold simultaneously.

3. novel 3D sand mold prints a preparation method for inorganic binder liquid curing-agent, it is characterized in that, comprises the steps:

Step one, by two acetoglycerides and triacetyl glycerine vavuum pump suction enamel reaction still, starts and stirs, stir more than 30min;

Step 2, adds vinylacetate, continues to stir more than 30min;

Step 3, adds absolute ethyl alcohol, methacrylic acid and xylitol successively, continues to stir more than 30min, obtains novel 3D sand mold and prints inorganic binder liquid curing-agent, then carry out detecting, packing.

4. a kind of novel 3D sand mold according to claim 3 prints the preparation method of inorganic binder liquid curing-agent, it is characterized in that, the 3D sand mold prepared prints inorganic binder liquid curing-agent, viscosity < 20mpa.s when 25 DEG C; Up time is 5min≤t≤15min, free acid content < 1.0%, water content < 0.5%.