KR102270193B1 - Cement-based composition and additive manufacturing method for 3D printing architectural exterior finishing materials - Google Patents

Abstract

The present invention relates to a cement-based composition for 3D printing and a manufacturing method for manufacturing a laminated building exterior panel and a sculpture, which can stably maintain a shape during lamination of atypical 3D printed architectural exterior panels and sculptures.
The present invention is 20 to 60% by weight of cement, 5 to 20% by weight of fly ash, 30 to 70% by weight of silica sand No. 8 and 1 to 10% by weight of EVA powder resin, 0.5 to 3% by weight of methylcellulose, It is characterized in that it contains 0.5 to 3% by weight of calcium formate powder, 0.1 to 2% by weight of carboxyl fluidizing agent powder.

Description

Cement-based composition and additive manufacturing method for 3D printing architectural exterior finishing materials for manufacturing laminated architectural exterior panels and sculptures

The present invention relates to a cement-based composition for 3D printing and a manufacturing method, and in particular, a cement-based composition for 3D printing for manufacturing a laminated architectural exterior panel and a sculpture that can stably maintain a shape during lamination of atypical 3D printed architectural exterior panels and sculptures; It relates to a manufacturing method.

The 3D printing technology field in the construction field is divided into structural materials and interior/exterior materials, and it is also closely related to the materials and composite materials constituting it. 3D printing technology can be applied in various fields related to the building industry and change the existing manufacturing process. It is recognized as the main technology that can make it happen. The structural material part of 3D printing technology is made by mixing and extruding materials suitable for 3D printing and stacking them one by one to continuously stack the walls that become the structures. In general, in the case of small materials, the supply of materials that satisfy additive manufacturing technology, design, economic efficiency and productivity, and large materials are laminated by applying structural reinforcement to form a single structure.

3D printing materials are classified according to the chemical composition of the material, thermophysical properties, the principle of 3D printing process technology, and the physical shape of the material. In general, in the case of small materials, additive manufacturing technology and production technology are linked to satisfy design, economic efficiency, and productivity. In the case of large materials, the concept of small items and reinforcement materials is lacking, so the development of additive manufacturing technology that secures strength and economy is required. Adequate level of additive manufacturing technology has not been prepared.

Korean Patent Publication No. 2017-0141348 (2017.12.26.)

Accordingly, the present invention has been proposed to solve the various problems of the prior art, and an object of the present invention is to manufacture a laminated architectural exterior panel and a sculpture that can stably maintain the shape when stacking atypical 3D printed architectural exterior panels and sculptures To provide a cement-based composition and manufacturing method for 3D printing.

In order to achieve the above object, the cement-based composition for 3D printing according to the technical idea of the present invention is for manufacturing a laminated building exterior panel and a sculpture, 20 to 60% by weight of cement, 5 to 20% by weight of fly ash, silica sand 8 Contains 30 to 70% by weight of powder, 1 to 10% by weight of EVA powder resin, 0.5 to 3% by weight of methylcellulose, 0.5 to 3% by weight of calcium formate powder, 0.1 to 2% by weight of carboxyl fluidizing agent powder It can be characterized by its technical configuration.

Here, the cement may be characterized by using a mixture of normal Portland cement and white Portland cement or using white Portland cement.

In addition, the fly ash may be characterized in that at least one of metakaolin and silica fume powder is added and used.

In addition, the fly ash may be characterized in that it is pulverized into fine powder for viscosity control and strength enhancement.

In addition, the silica sand may be characterized in that it is used for adjusting the degree, characterized in that it is pulverized into fine powder to control the viscosity.

In addition, the EVA powder resin may be characterized in that at least one of an aqueous polymer for cement admixture and a re-emulsification type powder resin is mixed and used.

After mixing water in the cement-based composition for 3D printing of the present invention, mixing to make a paste, and laminating them layer by layer using a 3D printer having a nozzle having a diameter of 3 to 10 mm, the required building material can be made.

On the other hand, the manufacturing method of the cement-based composition for 3D printing of the present invention is 20 to 60% by weight of cement, 5 to 20% by weight of fly ash, 30 to 70% by weight of silica sand No. 8, and 1 to 10% by weight of EVA powder resin , 0.5 to 3% by weight of methyl cellulose, 0.5 to 3% by weight of calcium formate powder, and 0.1 to 2% by weight of carboxyl fluidizing agent powder are mixed to prepare the technical composition.

The cement-based composition and manufacturing method for 3D printing for manufacturing laminated architectural exterior panels and sculptures according to the present invention can stably maintain the shape during lamination of atypical 3D printed architectural exterior panels and sculptures.

The cement-based composition for 3D printing according to the present invention is a key element of the 4th industrial revolution and has a wide application range in relation to additive manufacturing, so it is possible to secure related new technologies and increase domestic technology according to related product development and commercialization. It can be expected to secure world-class leading technology through unique technology development.

1 is a photo of a sample 3D-printed in a lamination method using a cement-based composition for 3D printing according to an embodiment of the present invention;
Figure 2 is a graph showing the diameter size of the raw material of the cement-based composition for 3D printing
3 is a graph comparing the fluidity of each specimen of the cement-based composition for 3D printing;
4 is a graph comparing the density of each specimen of the cement-based composition for 3D printing;
5 is a graph comparing the compressive strength of each specimen of the cement-based composition for 3D printing;
6a to 6c are comparative photographs and flow values of each specimen of cement-based composition through flow test.
7 is a comparative photograph of each specimen of the cement-based composition through the lamination test.
8 is a graph comparing the flowability of each test specimen series of the cement-based composition for 3D printing.
9 is a graph comparing the compressive strength of each test specimen series of a cement-based composition for 3D printing;

A cement-based composition for 3D printing according to embodiments of the present invention will be described in detail with reference to the accompanying drawings. Since the present invention can have various changes and can have various forms, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention. In describing each figure, like reference numerals have been used for like elements. In the accompanying drawings, the dimensions of the structures are enlarged than actual for clarity of the present invention, or shown reduced from reality in order to understand the schematic configuration.

Also, terms such as first and second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component. Meanwhile, unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

<Example>

The cement-based composition for 3D printing according to an embodiment of the present invention is for manufacturing a laminated architectural exterior panel and a sculpture, and is capable of stably maintaining the shape during lamination of an atypical 3D printing architectural exterior panel and a sculpture by a 3D printer.

To this end, the cement-based composition for 3D printing according to an embodiment of the present invention contains 20 to 60% by weight of cement, 5 to 20% by weight of fly ash, 30 to 70% by weight of silica sand No. 8, and 1 to 10% by weight of EVA powder resin. , 0.5 to 3% by weight of methylcellulose, 0.5 to 3% by weight of calcium formate powder, and 0.1 to 2% by weight of carboxyl fluidizing agent powder.

Here, the cement may be a mixture of normal Portland cement and white Portland cement, or white Portland cement may be used. If the amount of the cement used is less than 20% by weight, the compressive strength is not expressed and durability is greatly reduced, and if it exceeds 60% by weight, it interferes with mixing other components in sufficient amounts.

The fly ash plays an important role in imparting fluidity to the composition, and in order to maximize this, it is preferable to use by adding at least one of metakaolin and silica fume powder. The fly ash is preferably pulverized into fine powder for viscosity control and strength enhancement. If the mixing ratio of the fly ash is less than 5% by weight, the flowability is reduced during manufacture, and when it exceeds 20% by weight, it may cause a decrease in strength.

If the mixing ratio of the silica sand No. 8 is less than 40% by weight, shrinkage occurs, and when it exceeds 70% by weight, the strength decreases and the mixture is not sufficiently mixed. The silica sand should be used as fine particles having an average particle diameter of 0.05 to 0.17 mm, and coarse particles have a rough surface and are disadvantageous in lamination.

The S/C ratio is set to 1:1, and when it is used more than 1:1, it is disadvantageous for mixing and kneading.

If the mixing ratio of the EVA powder resin is less than 1% by weight, durability is lowered, and when it exceeds 10% by weight, strength is lowered. The EVA powder resin is preferably used by mixing at least one of an aqueous polymer for cement admixture and a re-emulsification type powder resin.

The methyl cellulose is used for the purpose of increasing the viscosity of the cement dough to make it advantageous for lamination, and when the mixing ratio is less than 0.5 wt%, the viscosity of the dough is not significantly improved, and when it exceeds 3 wt%, the viscosity becomes excessively high to make the dough This is not going well.

The calcium formate is included to control the setting time for lamination as a chemical admixture that promotes the setting of cement dough. If the mixing ratio of the calcium formate is less than 0.5% by weight, the setting time is not shortened well, and if it exceeds 3% by weight, the kneading becomes difficult due to rapid setting.

The carboxyl fluidizing agent is mixed to ensure fluidity of the cement dough. When the mixing ratio of the carboxyl fluidizing agent is less than 0.1% by weight, the fluidity of the dough is lowered and extrusion is difficult, and when it exceeds 2% by weight, the dough is loosened and material separation occurs.

In addition to the above main components, lightweight hollow silica may be additionally mixed to maximize lightness. The lightweight hollow silica is preferably mixed by 20 to 80% based on the weight of the silica sand. If the lightweight hollow silica is mixed in less than 20% compared to silica sand, the effect of reducing the weight is insignificant, and if it exceeds 80%, it may cause a decrease in strength.

In addition, 0.5 to 3% by weight of methyl cellulose for viscosity enhancement, 0.5 to 3% by weight of calcium formate powder for adjusting setting time, and 0.1 to 2% by weight of carboxyl fluidizing agent powder for controlling fluidity are further mixed. desirable.

<Experimental example>

After mixing water in the cement-based composition for 3D printing according to an embodiment of the present invention, mixing to make a paste, and laminating layer by layer using a 3D printer having a nozzle having a diameter of 3 to 10 mm, as shown in the photo of FIG. I got a product with At this time, 450 g of cement, 50 g of fly ash, 500 g of silica sand, 20 g of methyl cellulose, 5 g of calcium formate, 3 g of a carboxyl-based fluidizer and 45 g of ethylene vinyl acetate or 45 g of ethylene vinyl chloride and 250 g of water are mixed with a cement-based composition for 3D printing. was produced, and it was confirmed that the composition stably maintained its shape during lamination by the thus-prepared composition.

Subsequently, the results of confirming the characteristics expressed according to the component formulation for each test specimen will be described below. Table 1 shows the composition of the components according to each test specimen. For the mixing of each component, a forced mortar mixer was used, and for the homogeneity of each component, it was prepared by performing pre-bibeam.

Series W/C Cement fly ash Silica sand EVA Thickener Super
plasticizer CEFM 50 50-0 50 450 50 500 - - - 50-1 445.5 4.5 - - 50-3 437.8 13.5 - - 50-5 427.5 22.5 - - 50-10 405 45.0 - - 50-0-1 450 - 2.3 - 50-0-2 450 - - 0.5

The cement used in this experiment was normal Portland cement of S company, fly ash of N company was used as a mixture, and silica sand No. 8 company was used as aggregate. Fly ash is used as an admixture to replace cement, and its main components are silica (SiO ₂ ) and alumina (Al ₂ O ₃ ), which form a closed structure through a pozzolan reaction and have excellent light weight and chemical resistance. As the powder-type resin, W's EVA was used. Methylcellulose was used as a thickener, and a carboxyl-based fluidizer was used as a superplasticizer. The diameter distribution of each component is shown in FIG. 2 .

Comparing the fluidity of each specimen, as can be seen in the fluidity graph of FIG. 3, only 50-0-1, in which only a thickener was mixed without EVA powder resin or a fluidizing agent, lacked fluidity, and other specimens showed good fluidity. .

Comparing the densities of each specimen, as can be seen in the density graph of FIG. 4 , it was found that each specimen had an overall similar density. Only 50-0-1 mixed with only a thickener without EVA powder resin or a fluidizing agent was slightly reduced. It was found to have a low density.

Comparing the compressive strength of each specimen, as can be seen from the density graph of FIG. 5 , when the mixing amount of the EVA powder resin increased or when a thickener was mixed, the compressive strength was relatively low. On the other hand, it was found that an appropriate amount of EVA powder resin and fluidizing agent that is not excessively increased the compressive strength.

Continuing, another experimental example will be described. For another experiment, the basic mixing ratio is shown in Table 2 below.

W/C C FA S Superplast
icizer polymer Hardening
acceleration Thickener 0.4~0.6 900 100 1000 1 wt% or less 10% by weight or less 1-3 wt% or less 2% by weight or less

The admixture material was set to a content suitable for the characteristics of each material, the level of the basic material was set, and the mixing ratio used in the experiment is shown in Table 3 below. Corresponding to the cement-based composition for 3D printing according to an embodiment of the present invention, it was found that the C series specimen had relatively suitable strength for lamination.

W/C No. Cement fly ash Sand Superplast
icizer polymer Thickener EVCL Series
A=0.50
B=0.60
C=0.55 0 450 50 500 - - - One 450 50 500 0.1% by weight - - 2 450 50 500 0.1% by weight - - 3 445.5 50 500 - 1% by weight - 4 437.5 50 500 - 3% by weight - 5 427.5 50 500 - 5% by weight - 6 405 50 500 - 10% by weight - 7 450 50 500 - - 0.5% by weight 8 450 50 500 - - 1% by weight

The formulation was a basic experiment to check the applicability of 3D printing of the admixture material, and a flow table to check the viscosity and density and compressive strength tests were conducted to secure lightness. As a simple experiment to check the possibility of lamination, lamination was carried out by hand using a pastry bag. The water-cement ratio of the formulation was determined at three levels, and the use of the binder was classified by number. The fluidizing agent and thickening agent were set at a level of 1% by weight or less, and two levels were performed in the experiment. The polymer was designed by blending in 4 levels of 1, 3, 5, and 10 wt%.

The flow test is a basic test to find out the viscosity of each specimen, and it was measured as the average diameter of the dough. Lamination was a simple experiment using a pastry bag to confirm the possibility of lamination by squeezing it by hand. 6A to 6C are photographs and flow values of each specimen compared during the flow test, and FIG. 7 is a photograph showing whether each specimen can be stacked.

In the case of series A, lamination was possible with a low water ratio, but in a simple experiment using hands, there was a limitation in hand weaving, so lamination was difficult.

As a result of the experiment, 55% of the water ratio was judged to be appropriate, and mixing was difficult below 50%, and the fluidity was higher as the water ratio was higher and increased as the EVCL mixing amount increased.

Material separation occurs even when a small amount of the fluidizing agent is added, and it was judged that it is suitable to use a very small amount to improve the viscosity.

The use of the thickener is difficult to knead and molded, and the flow is low, so the viscosity improvement is quite effective, and it is judged that it can be used by setting an appropriate amount according to the water ratio and admixture material.

EVCL and fluidizer form a lot of bubbles in the dough, making the dough softer and lowering the viscosity to increase the flow. In the case of thickeners and EVCL, lamination is possible. In this case, it was found that the surface was smooth and there was no sagging in the lower layer of the laminated specimen, which was advantageous for lamination.

8 is a summary of flow values between series of test specimens, and it was shown that, regardless of the formulation, the increase in water increases the fluidity, and the fluidity increases as the amount of EVCL mixed increases.

9 shows a comparison of the compressive strength between series of specimens. The compressive strength was highest at 55% water ratio, and the strength decreased as the EVCL content increased. In the case of formulation A, it was found that the kneading was not performed well, and the strength was rather reduced in the absence of an admixture material.

The thickener showed low strength because it was difficult to mold the specimen due to its viscosity, and the fluidizing agent was found to lower the strength due to the incorporation of air bubbles in a large amount. Compressive strength is significantly lowered as the amount of EVCL mixed increases, and when more than 5% of EVCL is mixed, there is a limit to strength expression.

Although preferred embodiments of the present invention have been described above, various changes, modifications and equivalents may be used in the present invention. It is clear that the present invention can be equally applied by appropriately modifying the above embodiments. Accordingly, the above description is not intended to limit the scope of the present invention, which is defined by the limits of the following claims.

Claims (12)

Cement 20-60 wt%, fly ash 5-20 wt%, silica sand No. 8 30-70 wt% powder, EVA powder resin 1-10 wt%, methylcellulose 0.5-3 wt%, calcium formate powder 0.5 to 3% by weight, including 01 to 2% by weight of carboxyl fluidizing agent powder,
The cement is usually used by mixing Portland cement and white Portland cement or using white Portland cement,
The silica sand will have an average particle diameter of 0.05 to 0.17 mm,
The fly ash is a cement-based composition for 3D printing, characterized in that it is used by adding at least one of metakaolin and silica fume powder. delete delete According to claim 1,
The fly ash is a cement-based composition for 3D printing, characterized in that it is pulverized into fine powder for viscosity control and strength enhancement. According to claim 1,
The silica sand is a cement-based composition for 3D printing, characterized in that it is pulverized into fine powder to control the viscosity. According to claim 1,
The EVA powder resin is a cement-based composition for 3D printing, characterized in that it is used by mixing at least one of an aqueous polymer for cement admixture and a re-emulsifying powder resin. 7. After mixing water with the cement-based composition for 3D printing of any one of claims 1 and 4 to 6, mix to make a paste,
A building material, characterized in that it is manufactured by laminating one layer at a time using a 3D printer having a nozzle having a diameter of 3 to 10 mm. A method of manufacturing a cement-based composition for 3D printing for manufacturing a laminated architectural exterior panel and a sculpture,
Cement 20-60 wt%, fly ash 5-20 wt%, silica sand No. 8 30-70 wt% powder, EVA powder resin 1-10 wt%, methylcellulose 0.5-3 wt%, calcium formate powder 0.5 to 3% by weight, but prepared by mixing 0.1 to 2% by weight of carboxyl fluidizing agent powder,
The cement is usually used by mixing Portland cement and white Portland cement or using white Portland cement,
The silica sand uses an average particle diameter of 0.05 to 0.17 mm,
The fly ash is a method of manufacturing a cement-based composition for 3D printing, characterized in that it is prepared by adding at least one of metakaolin and silica fume powder. delete delete 9. The method of claim 8,
The method for producing a cement-based composition for 3D printing, characterized in that the silica sand is pulverized into fine powder to control the viscosity. 9. The method of claim 8,
The method of manufacturing a cement-based composition for 3D printing, characterized in that the EVA powder resin is used by mixing at least one of an aqueous polymer for cement admixture and a re-emulsifying powder resin.

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