Method for manufacturing and using a composite fluid

Abstract

A method for producing a composite fluid of a foamy liquid material suitable for use in 3D printing is disclosed, comprising generating primary bubbles, and optionally secondary and tertiary bubbles, in a liquid material for printing 3D objects or as a support material for use as a printing ink, wherein the liquid material contains at least primary bubbles.

Description

[Technical Field]

[0001] (Field) This disclosure relates to the production of a bubbly liquid (or bubbly liquid) having complex fluid properties used in additive manufacturing (or additive manufacturing). [Background technology]

[0002] (background) In the manufacture of 3D printed objects (or objects) with diverse and complex shapes, there may be shapes or parts of shapes that cannot be balanced by the body of the printable object, and therefore, the printing material may collapse due to gravity, such as fatal overhangs. Various attempts can be used to overcome this problem, such as printing the material in a support bath and multi-channel plots by co-extruding a temporary support material together with the main printing material. When a support path is used, Newtonian and non-Newtonian liquids and gels have physical properties that cause movement of the support material and elongation of the printable material under shear stress caused by the movement of the injection head of the 3D printing device (or device). This causes deformation and inaccuracies in the printable object. Furthermore, despite their possible high viscosity, liquid support materials may not adequately support the printable material against the effects of gravity, for example, if the density of the printable material is high due to heavy filler particles. Furthermore, changes in the viscosity of the liquid support material at different temperatures or pH levels, as seen in polyacrylic acid hydrogels (carbomers), can lead to inaccuracies in the printed object. Moreover, when considering printing materials, viscosity stability at various temperatures is a desirable characteristic.

[0003] The support material must have a liquid-like continuous phase through which the print head (or printing head) moves. Simultaneously, this continuous fluid phase must exhibit plastic behavior when shear stress is applied to the support material due to the movement of the print head. Furthermore, viscosity temperature sweep stability (or temperature sweep stability) and biocompatibility are required properties for both the support material and the printing material. [Overview of the project]

[0004] (Brief explanation) The scope of protection required for the various embodiments of the present invention is presented by the independent claims. Any exemplary embodiments and features described herein that do not fall within the scope of the independent claims should be interpreted as useful examples for understanding the various embodiments of the present invention.

[0005] According to a first aspect, there exists a method for producing a composite fluid of a foamy liquid material suitable for use in 3D printing, the method comprising generating at least primary bubbles, and optionally secondary and / or tertiary bubbles, in a liquid material for use as a support material for printing 3D objects or as a printing ink, wherein the liquid material contains at least primary bubbles.

[0006] According to a second aspect, there exists a system for 3D printing, the system comprising at least a print head configured to eject a printing material to form a 3D printed object, the system further comprising controlling the 3D printing by a control unit, and the system configured to eject the printing material onto a support material manufactured using the method. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows a foaming liquid system having primary bubbles and printable material. [Figure 2]Figure 2 shows a foamy liquid system containing primary and secondary bubbles and a printable material. [Figure 3] Figures 3A and 3B illustrate the collapse and runoff of additional material due to gravity and the effect of a foamy liquid resisting the effects of gravity. [Figure 4] Figure 4 shows the static flow of liquids of the same composition without bubbles. [Figure 5] Figure 5 shows the viscosity stability at various temperatures when using a free radical-forming crosslinking agent. [Figure 6] Figure 6 shows the viscosity stability of calcium chloride crosslinking agents at various temperatures. [Modes for carrying out the invention]

[0008] (Detailed explanation) The following embodiments are illustrative. While this specification may refer to “an,” “one,” or “several” embodiments in several places, this does not necessarily mean that each reference is made to the same embodiment, or that certain features are limited to a single embodiment. A single feature from different embodiments may be combined to provide other embodiments.

[0009] Disclosed are methods and systems for producing a foamy liquid material that can be transformed by a jamming transition from a Newtonian or non-Newtonian liquid material into a foamy liquid material having the plastic deformation properties and stable temperature sweep properties of a composite fluid. The resulting foamy liquid material can be used as a 3D printing support material in a 3D printing system or as a printing material (printing ink) in bioprinting.

[0010] In exemplary embodiments, a foamy liquid material is formed by generating primary bubbles in the liquid material. This can be achieved, for example, by adding a surfactant to a Newtonian liquid and causing primary bubbles to form in the liquid by physical means such as an aerator or shaking, thereby creating a composite fluid of the first type of foamy liquid.

[0011] The viscosity of the single-bubble liquid material can also be changed by adding free radicals or molecular compounds to the continuous liquid phase, after which a chemical reaction forms secondary bubbles, creating a composite fluid of the second type of bubble-forming liquid.

[0012] Optionally, tertiary bubbles are generated in the bubble-forming liquid material by a chemical reaction, a physical means of injecting gas into the bubble-forming liquid material, or a biological process to make the bubble-forming liquid into a third type of composite fluid (multimodal bubble system).

[0013] Thus, the bubble-forming liquid material can have a gas bubble system with one or more different sizes and gas compositions.

[0014] Gas bubbles can reduce the buoyancy effect of the continuous liquid phase due to the surface tension of the gas bubbles and can impede the effect of gravity on the printable object.

[0015] The composite fluid of the first, second, or third type can also reduce the effect of Archimedes' principle and hold additional printing materials vertically (in the y-direction) in a predetermined position.

[0016] The continuous liquid phase of the bubble-forming liquid, i.e., the composite fluid of the first, second, or third type, traps gas bubbles inside the bubble-forming liquid and prevents the collapse and coalescence (or adhesion) of the gas bubbles.

[0017] The jamming transition of the composite fluid of the first, second, or third type, and the bubble-forming liquid material affects the firmness (or stiffness) and rigidity (or hardness) of the bubble-forming liquid so as to support additional materials in the bubble-forming liquid to maintain the desired x-y-z position and volume form.

[0018] Additional compounds in the composite fluid can change their physical states from fluid and fluid-like states to semi-solid states. The additional compounds can be calcium chloride, isocyanate, epichlorohydrin, aldehyde derivatives such as glutaraldehyde, urea derivatives or carboxylic acids, or transition metals of Group III elements, and / or free radical-forming compounds. Also, the additional materials can affect the behavior, function, and physical state of the printed material.

[0019] The viscosity and physical state of the foamy liquid can be changed by coexisting chemical reactions in the foamy liquid and by the addition of nanoparticles or molecules for emulsions, suspensions, colloidal systems, proteins, microorganisms, yeasts, and cells, depending on the primary, secondary, and tertiary types of the composite fluid.

[0020] The foamy liquid material as a support material for the printed material does not solidify by polymerization, but when the foamy liquid material is used as a printing ink, it may include the solidification of a cross-linking agent compound.

[0021] The temperature sweep characteristics of the viscosity of the foamy liquid material can be stable at different temperatures.

[0022] Non-Newtonian liquids are characterized by viscosities that change with motion. Most non-Newtonian liquids have a molecular chain structure and can also be composite fluids. A composite fluid is a mixture having two or several phases of solid-liquid (suspension), solid-gas, liquid-gas (foam (or, foamy substance or foam body: foam)), or liquid-liquid (emulsion). The mechanical response of a composite fluid includes a transition between solid-like behavior, including plastic deformation, and fluid-like behavior. A composite fluid having plastic deformation in shear, for example, can be cut. This type of material is called a Bingham plastic.

[0023] Foaming liquids, a type of composite fluid, can also be referred to as foaming liquid materials and contain a continuous liquid phase and approximately 50% gas bubbles. High volume loads of gas bubbles cause the material to foam. Bubbles modify (or alter) the rheology of the liquid by resisting deformation, and the behavior of the liquid is influenced by the properties of the continuous liquid phase and the size-bubble-volume fraction of the bubbles. The surface tension of the bubbles balances the outward force of air pressure with the weight of the substance in the foaming liquid due to Laplace pressure. Bubbles form in a liquid when the amount of dissolved gas exceeds the limit of its solubility in the liquid, and the gas molecules join together in aggregates (or aggregates) that form gas bubbles. Unless the viscous and plasticity physical properties of the continuous liquid phase prevent the bubbles from floating by trapping them, the gas bubbles float due to their low density, thus stabilizing the foaming liquid. Furthermore, the trapping of gas bubbles in a liquid is also influenced by friction, known as drag (or resistance) or fluid resistance.

[0024] Archimedes' principle explains the buoyancy of a floating object when additional material is placed in a liquid. The buoyancy effect on the material or object is equal to the weight of the liquid it replaces. However, if the liquid is filled with gas bubbles, the weight is substantially less than that of a liquid without gas bubbles, and the buoyancy effect is reduced. The balance (or equilibrium) of the buoyancy effect, the effect of gravity, and the surface tension of the gas bubbles holds the additional material and object in a stable position in the liquid. The buoyancy effect can also be explained by the collision of water molecules with the floating object, rather than by the weight of the liquid it replaces. In this case, the gas bubbles would also reduce the number of water molecules, resulting in less suspension in the foamy liquid. It is also worth noting the emphasis on the effect of surface tension, i.e., the effect of the density difference between the liquid phase and the gas phase, which is typically effective on the liquid surface that causes light objects to float. Furthermore, if gas bubbles are present, a density difference also exists within the liquid itself.

[0025] Gas bubbles (or gas bubbles) can be produced by physical means such as the use of an aerator and shaking of the liquid, as well as by chemical reactions in a liquid material to generate gas. The continuous liquid phase is typically made from Newtonian liquid water, and by adding surfactants such as soap to the water, the surface tension of the water is lowered and foaming is increased. Ordinary foam is an unstable system, and the foam disappears over time. If the surfactant also increases the viscosity of the water, making the liquid a compound fluid, the collapse time of the bubbles may be prolonged, or the bubbles may even be trapped in the continuous liquid phase. One compound that lowers the surface tension of water and promotes (or enhances) bubble formation is methylcellulose (C6H7O2(OH) x (OCH3) y ), hydroxypropyl methylcellulose (C 56 H 108 O 30 ) or chitin (C8H 13 O5N) nMethylcellulose hydrogels (or hydrogels) can be aerated (or aerated) by aerator or shaking. To stabilize the methylcellulose hydrogel and air bubbles, and to increase its viscosity and bring the liquid to a non-Newtonian state, the affinity of methylcellulose polymers for crosslinking is enhanced by free radical-forming compounds in the methylcellulose aqueous liquid. Examples of crosslinking enhancing compounds (or crosslinking-enhancing compounds) include 4,4'-azobis(4-cyanopentanoic acid), which forms hydroxyl radicals in the liquid after the addition of the crosslinking enhancing compound, thioxanthone-based hydrophilic crosslinkers (e.g., TX-MPEG350, TX-MPEG550, and TX-MPEG750), and lithium phenyl-2,4,6-trimethylbenzoyl phosphinate (LAP). Another example of a crosslinking enhancing compound is silyl glyoxylate. Other crosslinking agents for crosslinking methylcellulose include epichlorohydrins, aldehyde reagents, urea derivatives, polyfunctional carboxylic acids such as citrate, and platinum group transition metals. In the crosslinking chain, copolymerization with the vinyl groups of methylcellulose occurs in the presence of water, and a hydrogel begins to form. Air bubbles generated in the hydrogel by shaking or aerator are called the first type of composite fluid. Figure 1 shows an example of such primary bubbles 120 in a foamy liquid material 105 produced for use as a support material for 3D printing. The primary bubbles 120 can be, for example, 0.1 to 1.0 mm in diameter (Figure 1). The amount of methylcellulose can be 1 to 20% by weight of water, preferably 5% by weight. The surface tension 125 of the air bubbles and the density difference between the gas and liquid balance the outward force of the air pressure, supporting the printable material extruded from the print head 110 used for 3D printing in the 3D printing system 100, and forming a printable object 115 from run-off due to gravity.Non-Newtonian hydrogels can retain air bubbles for longer periods than Newtonian hydrogels, while water hydrogels do not trap gas bubbles, and when hydrogels are used as support materials for 3D printing, gas bubbles will disappear over time.

[0026] Thus, less than one second after the injection of the resin material before polymerization begins, the overhang will collapse due to the force of gravity, as shown in Figure 2. In Figure 2, there is a chart where the y-axis is outflow (mm) and the x-axis is time from the start of printing. Printing can be performed using a 3D printing system such as Printing System 3D. Generally, a 3D printing system includes a print head configured to inject the printing material into a support material which may be a bubbly liquid of a composite fluid. Printing can be controlled by a control unit coupled to the print head using any suitable mechanism for coupling. It should also be noted that printing can be controlled, at least in part, using computer program instructions. In Figure 2, the force of gravity 230 affects the overhang of the object being printed 220. In scenario b), the printed object 220 has an overhang. In scenario a), there are no gas bubbles in the hydrogel used as the support material, and as a result, there is outflow of the overhang (or protrusion or projection). In scenario b), object 220 is printed and has an overhang. In this scenario b), hydrogel support materials of first, second, and third types of composite fluids having primary, secondary, and tertiary gas bubbles provide support for the overhang. Additional (or further) compounds such as cellulose nanocrystals (CNC) or other polysaccharides such as sucrose or fructose can be added to the hydrogel to stabilize the bubble liquid to trap air bubbles. When sucrose is used to stabilize bubbles, the sugar content can be 10 to 150% by weight of water, preferably 80% by weight.

[0027] The composite fluid properties and homogeneity of hydrogels can be enhanced by additional secondary gas bubbles, which can be nitrogen gas (N2) containing bubbles with a diameter of, for example, 0.01–0.1 mm. The effect of primary and secondary gas bubbles, i.e., first and second types of composite fluids, on the static flow of 300 10 ml hydrogel droplets on a glass plate is shown by measuring the diffusion (or spreading) of the hydrogel droplets at room temperature and pressure (RTP) for 20 minutes (Figure 3A) in the examples shown in Figures 3A and 3B. Groups A–D, having the same composition of methylcellulose and sucrose, are as follows: A: no primary, secondary, and tertiary bubbles (no composite fluid, control), B: with secondary bubbles, C: with primary and secondary bubbles. The arrows schematically show the width (diffusion) of the droplets after 20 minutes. Figure 3B shows that the diffusion of hydrogels with the same composition but different gas bubble structures behaves differently in terms of their flow properties.

[0028] The source of secondary gas bubbles, which may function as protective gases such as N2 and argon (Ar) to enhance the free radical polymerization of the printable resin material, is a chemical reaction in the hydrogel. The secondary gas bubbles increase the homogeneity of the hydrogel and fill larger primary air bubbles (or air bubbles or air bubbles). This is shown in Figure 4, where secondary bubbles 425 are present in a support material 405. This support material is used with a printing system 400 in which a print head 410 is present, and the print head 410 injects the printing material into the support material 405 to produce a 3D printed object 415 including overhangs. The support material 405 also contains primary bubbles 420. The printing system 400 in this exemplary embodiment may further include a control unit configured to control the movement of the print head 410 and the injection of the printing material. This control can be achieved using appropriate mechanical structures and software for controlling the 3D printing process. Having secondary bubbles 405 improves the surface smoothness of the printable object 415 if the hydrogel is used as a support material 405 for the 3D printed object 415 having overhangs. The bubble system of the composite fluid having viscosity (or consistency) and plastic deformation provides support for the resin material to be 3D printed on the hydrogel used as the printing material and support material 405, eliminating material outflow due to the force of gravity, the effect of which is shown in Figure 2.

[0029] The first, second, or third type of composite fluid, i.e., methylcellulose and sugar hydrogel support materials having different bubble systems, exhibit stable viscosity at various temperatures (temperature sweeps), which is not the case for other hydrogels such as agar, alginate, or gelatin hydrogels shown in Figure 5, which show a decrease in viscosity as the temperature increases. The viscosity of the composite fluid hydrogel made from methyl cellulose and sucrose varies from 21 to 300 Pa·s for the hydrogel (530) of the example, for example, it is 70 Pa·s. The viscosity is stable at temperatures of 5°C to 60°C and 20°C to 40°C in the first type of methyl cellulose - sucrose hydrogel composite fluid in the examples (510, 520). However, for the composite fluid of the second type of composite fluid species, the methyl cellulose - sucrose hydrogel contains a UV - sensitive compound. When irradiated with UV at a wavelength of 360 - 400 nm, an irradiation power of 14 mW / cm2, and a total energy of 0.69 J / cm 2 for 1 minute, its viscosity increases to 145 Pa·s (540) and still has temperature - sweep stability. For comparison, common hydrogels using agar and gelatin have their viscosity decrease from 175 to 5 Pa·s when the temperature is increased from 20°C to 40°C (550).

[0030] Also, the hydrogels of the first, second, or third type of methyl cellulose - sucrose composite fluid can be combined by an additional cross - linking compound such as calcium chloride (CaCl2) that releases Ca 2+ ions to bind the methyl cellulose and sucrose units of the composite fluid into an ionic complex containing oppositely charged molecules and Ca 2+ ions. Other ions that can be used for cross - linking are Mg 2+ and Ba 2+ . When CaCl2 is used to release Ca[[ID=十五]] 2+ ions in the methyl cellulose - sucrose composite fluid, its concentration varies between 0.1 and 20 wt% of the water content of the composite fluid. Figure 6 shows the viscosity stability of the material with a calcium chloride cross - linking agent at various temperatures. The hydrogel of the methyl cellulose - sucrose composite fluid with a 2.0 wt% CaCl2 cross - linking agent maintains a stable viscosity (61) at temperatures of 20 - 40°C (temperature - sweep stability). Ca 2+ ions affect the physical state of substances such as printing materials like bio - ink. The bio - ink of nanofibrillated cellulose - sodium alginate hydrogel contains Ca 2+It can be printed on hydrogel composite fluids containing ions. By printing nanofibrillated cellulose-sodium alginate hydrogel onto a first type of composite fluid containing 0.1 to 18.0% by weight, preferably 2% by weight, of calcium chloride, the printable hydrogel crosslinks upon contact with the composite fluid, and its material state changes. Crosslinking stabilizes the shape of the printable object, even with complex overhangs, and in 3D cell culture, allows cells to grow according to the shape of the printable object and form tissue. Ca 2+ Printing bioinks onto hydrogel composite fluids containing ionic crosslinking agents eliminates the need for a separate process involving crosslinking agents to immerse the printed object (a cell-containing structure) after printing. Furthermore, the hydrogel composite fluid supports the shape of cell-containing structures, even in the formation or design of complex tissue engineering scaffolds. Other compounds used to modify the rheology of the hydrogel composite fluid and influence the material state of the printed object include aldehyde derivatives such as glutaraldehyde, urea derivatives, carboxylic acids, and isocyanates.

[0031] Furthermore, other hydrogels besides methylcellulose can also be prepared to become a composite fluid by shaking or aerating, or by adding sucrose molecules or several other molecules, as required for the composite fluid. Nonionic polyacrylamide (PAM)((C3H5NO) n )-Water hydrogel (PAH), polyethylene glycol (PEG)-water hydrogel, polyacrylic acid, cellulose microfibrils, cellulose nanocrystals, potassium salts, chitosan, alginates, polyvinyl alcohol, starch, gelatin hydrogel, and methacrylated galactoglucomannan can be used as 3D printing support materials or printable materials for bio-inks. Biodegradable hydrogels are naturally based hydrogels such as polysaccharides (e.g., chitosan) and proteins (e.g., collagen), or synthetic hydrogels such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA), and polypropylene fumarate (PPF).

[0032] Furthermore, there are other types of hydrogels that can be printed on first, second, or third type composite fluid hydrogel support materials in order to change the state of the substance to a semi-solid or solid state. An example of a photocurable printable hydrogel is PEG-DA=polyethylene glycol diacrylate-water (40 / 60%) containing 0.2% 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophene (HOCH2CH2OC6H4COC(CH3)2OH) (IRGACURE) photopolymerization initiator, with an additional 33 wt% calcium carbonate filler. The presence of free radicals due to the reaction of photopolymerization initiators in the printing material or support material can be harmful to living cells, and therefore, composite fluids for printing materials and support materials that do not contain free radical-forming compounds are preferred in order to maintain the viability of human or animal-derived stem cells, osteocytes, endothelial cells, neutral cells, chondrocytes, hematopoietic cells, and fibroblasts. Calcium chloride crosslinking agents are preferred when the hydrogel composite fluid is used as a bioink and contains living cells for tissue engineering or drug development purposes. Primary bubbles of oxygen-containing air enhance the living cell conditions in the bioink printing process.

[0033] For silicone (organopolysiloxane) elastomers, the crosslinking compound can be a photopolymerization initiator such as a thioxanthone. First, second, or third type composite fluids containing silicone polymerization-promoting compounds of thioxanthone-based hydrophilic visible light polymerization initiators (TX-MPEG350, TX-MPEG550, and TX-MPEG750) can be used for 3D printing. The composite fluids may contain catalysts such as palladium, rhodium, germanium, platinum transition metals, their salts, or complexes of typical Group III elements (e.g., Karstedts' catalyst) to promote the polymerization of the silicone elastomer. In the first, second, or third type composite fluids, the transition metal (Group III) ions or complexes for silicone polymerization are water or DMSO (dimethyl sulfoxide) soluble compounds such as cisplatin (cis-(Pt(NH3)2Cl2)) or chloroplatic acid. Other suitable catalysts are platinum vinylsiloxane complexes and platinum phosphine complexes.

[0034] The first, second, or third type of hydrogel composite fluid can also be used to print metal or ceramic-filled materials onto plaster or concrete in a green stage for sintering after the printing process. For this purpose, ceramic metal particles are mixed into a photo- or chemically curable resin matrix, printed onto the hydrogel composite fluid, crosslinked with free radicals, and then sintered at the fusion temperature of the metal or ceramic filler.

[0035] This method and composite fluid system can be used as a 3D printing support material or printing ink for several other applications that leverage the advantages of complex spatial or omnidirectional printing. These include aerospace and automotive and their components, soft robotics, electronics, pneumatic and fluid elastomer actuators, sporting goods, printed textiles, tools, customized industrial products, furniture, interior furnishings and decorations, and architectural and engineering applications. Due to its biocompatibility and non-toxicity, the hydrogel composite fluid can also be used in everyday products such as food and packaging, cosmetics, medical or dental devices for humans or animals, artwork, and testing platforms for pharmaceutical development. Furthermore, this composite fluid system can be used as a cleansing foam or moisturizer for skin products, including pharmaceuticals for skin diseases or drug delivery for iontophoresis therapy.

[0036] A method for producing a composite fluid of a foamy liquid material suitable for use in 3D printing may include generating primary bubbles in the liquid material as a support material for printing 3D objects or for use as a printing ink. Optionally, secondary bubbles and / or tertiary bubbles are generated in the liquid material as a support material for printing 3D objects or for use as a printing ink. The liquid material may contain at least primary bubbles, and optionally secondary bubbles and / or tertiary bubbles.

[0037] This method may further include a rheological transition of the liquid phase to a viscous liquid and the temperature sweep stability of a viscosity of 20.1 to 300.0 Pa·s. Primary bubble generation may include adding a surfactant to the liquid material, the liquid material being a Newtonian or non-Newtonian liquid material, and shaking the liquid material or using an aerator.

[0038] This method may involve stabilizing primary bubbles by adding free radicals, ions, molecular compounds, nanofillers, or cellular functions to a continuous liquid phase of a liquid material. Compounds of the composite fluid foaming liquid material may alter the material state of printing inks upon contact with the liquid material.

[0039] This method may include generating secondary bubbles in a liquid material by a chemical reaction. This method may further include generating tertiary bubbles in a liquid material by injecting a gas into the liquid material or by a chemical reaction.

[0040] Bubbles can be composed of bubble systems, and the bubble system and the bubbles within it have one or more different gas compositions. Secondary and / or tertiary bubbles may contain air or nitrogen gas.

[0041] The liquid material may be a hydrogel and may contain cross-linked compounds or living cells.

[0042] A system for 3D printing may include at least a print head configured to inject printing material to form a 3D printed object, the system further includes controlling the 3D printing by a control unit, and the system is configured to inject the printing material into a support material manufactured using the method.

Claims

1. A method for producing a composite fluid of a foamy liquid material suitable for use in 3D printing, A method for manufacturing a liquid material, comprising generating primary bubbles, and optionally secondary and / or tertiary bubbles, in a liquid material for printing a 3D object or for use as a support material for printing ink, wherein the liquid material contains at least primary bubbles.

2. The manufacturing method according to claim 1, further comprising causing a rheological transition of the liquid phase to a viscous liquid and temperature sweep stability of a viscosity of 20.1 to 300.0 Pa·s.

3. The ability to generate primary bubbles is Adding surfactants to liquid materials; and Shake the liquid material or use an aerator. Includes, The manufacturing method according to claim 1 or 2, wherein the liquid material is a Newtonian or non-Newtonian liquid material.

4. A manufacturing method according to any one of claims 1 to 3, comprising stabilizing primary bubbles by adding free radicals, ions, molecular compounds, nanofillers, or cellular functions to a continuous liquid phase of a liquid material.

5. The manufacturing method according to any one of claims 1 to 4, wherein the compound of the foamy liquid material of the composite fluid changes the material state of the printing ink when it comes into contact with the liquid material.

6. A manufacturing method according to any one of claims 1 to 5, comprising generating secondary bubbles in a liquid material by a chemical reaction.

7. The manufacturing method according to any one of claims 1 to 6, further comprising generating tertiary bubbles in a liquid material by injecting a gas into the liquid material or by a chemical reaction.

8. The manufacturing method according to any one of claims 1 to 7, wherein bubbles are formed within a bubble system, and the bubble system and the bubbles within the bubble system have one or several different gas compositions.

9. The manufacturing method according to any one of claims 1 to 8, wherein the secondary bubbles and / or tertiary bubbles contain air or nitrogen gas.

10. A method for producing a liquid material according to any one of claims 1 to 9, wherein the liquid material is a hydrogel and comprises a crosslinking compound and living cells.

11. A 3D printing system, A 3D printing system comprising at least a print head configured to inject a printing material to form a 3D printed object, further comprising controlling the 3D printing by a control unit, and the system configured to inject the printing material into a support material manufactured using the method according to any one of claims 1 to 10.

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