Green high-molecular ultralight clay material as well as preparation method and application thereof

Abstract

The invention discloses a green high-molecular ultralight clay material as well as a preparation method and application thereof, and belongs to the technical field of high-molecular material preparation. The green polymer ultralight clay material comprises the following raw materials: 5-35 wt% of polyvinyl alcohol, 5-70 wt% of hollow microspheres, 1-40 wt% of inorganic salt and the balance of water, and preparing a blended solution of the raw materials, defoaming the blended solution, and carrying out constant-temperature and constant-humidity water loss treatment to obtain the composite material. According to the invention, through a controllable water loss process, a high-molecular mud-like toy material with green and environment-friendly characteristics is constructed in situ. Wide-range adjustable density, plasticity and mechanical properties can be realized by adjusting the contents of polyvinyl alcohol, inorganic salt and hollow microspheres, the water content and the types of auxiliaries. The prepared material has the mechanical characteristics of high plasticity and high flexibility, has ultralow density and better heat insulation property, contains no cross-linking agent, is simple, non-toxic, green and environment-friendly, and can expand the application of the plastic material in different fields.

Description

Technical Field

[0001] This invention belongs to the field of polymer material preparation technology, specifically relating to a green polymer ultralight clay material and its preparation method and application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Superlight clay, as an emerging craft material, has garnered widespread attention in children's toys, education, and creative design due to its lightweight, malleable, and environmentally friendly characteristics. Traditional superlight clay is primarily prepared by physically mixing raw materials such as polyvinyl alcohol, foaming powder (e.g., hollow microspheres), water, and crosslinking agents. However, existing technologies still have significant limitations: First, most products rely on boric acid or borax as crosslinking agents, posing potential toxicity risks. Although boron-free improvements have been made (e.g., using glutaraldehyde), environmental friendliness and safety still need improvement. Second, the material's water retention is insufficient, making it prone to drying and cracking when exposed to air, affecting its malleability and lifespan. Third, achieving lightweight often sacrifices mechanical stability, while prioritizing mechanical properties makes it difficult to simultaneously achieve lightweight properties. Furthermore, existing processes, such as the freeze-thaw method, are energy-intensive or rely on complex additives, hindering large-scale production and application. Therefore, developing a superlight clay material that combines excellent water retention, safety and environmental friendliness, lightweight stability, and a simple manufacturing process has become an urgent industry need. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a green polymer ultralight clay material, its preparation method, and its application. The green polymer ultralight clay material provided by this invention has high plasticity, high flexibility, ultra-low density, and good thermal insulation properties. Furthermore, it is free of crosslinking agents, has a simple and non-toxic composition, and is environmentally friendly. It can expand the application of plastic materials in different fields, such as children's space clay toys, cushioning materials, thermal insulation materials, and sound insulation materials.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing a green polymer ultralight clay material, wherein the raw material composition of the green polymer ultralight clay material is: 5-35 wt% polyvinyl alcohol, 5-70 wt% hollow microspheres, 1-40 wt% inorganic salt, and the remainder being water; the preparation method includes: preparing a blending solution of the raw materials, defoaming the blending solution, and then subjecting it to a constant temperature and humidity dehydration treatment to obtain the green polymer ultralight clay material. In some embodiments of the present invention, the green polymer ultralight clay material further includes 0.1-10 wt% additives; the additives include one or more of functional fillers, dyes, foaming agents, humectants and antibacterial agents. Preferably, the functional filler includes at least one of graphene, carbon nanotubes, and MXene.

[0006] Preferably, the dye includes at least one of Congo red, methyl orange, rhodamine B, methylene blue, and crystal violet.

[0007] Preferably, the foaming agent includes at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium α-alkenyl sulfonate, triethanolamine lauryl sulfate, and sodium lauryl polyoxyethylene ether carboxylate.

[0008] Preferably, the moisturizer includes at least one of glycerin, propylene glycol, butylene glycol, polyethylene glycol, and sorbitol.

[0009] Preferably, the antibacterial agent includes a silver ion antibacterial agent. In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 10-35 wt% polyvinyl alcohol, 5-70 wt% hollow microspheres, 10-40 wt% inorganic salts, and the remainder is water.

[0010] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 10-25 wt% polyvinyl alcohol, 5-50 wt% hollow microspheres, 20-40 wt% inorganic salts, and the remainder is water.

[0011] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol, 20 wt% hollow microspheres, 22 wt% inorganic salt, and the remainder is water.

[0012] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 14 wt% polyvinyl alcohol, 20 wt% hollow microspheres, 22 wt% inorganic salts, and the remainder is water.

[0013] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol, 5 wt% hollow microspheres, 22 wt% inorganic salt, and the remainder is water.

[0014] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol, 20 wt% hollow microspheres, 33 wt% inorganic salt, and the remainder is water.

[0015] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is as follows: 10-25 wt% polyvinyl alcohol, 5-50 wt% hollow microspheres, 20-40 wt% inorganic salts, 0.1-10 wt% additives, and the remainder is water.

[0016] Preferably, the raw material composition of the green polymer ultralight clay material is: 10-25 wt% polyvinyl alcohol, 5-50 wt% hollow microspheres, 20-40 wt% inorganic salt, 0.1-10 wt% MXene, and the remainder is water.

[0017] In some embodiments of the present invention, the number average molecular weight of the polyvinyl alcohol is 7,000-200,000, and the degree of alcoholysis is 80-99.9%. In some embodiments of the present invention, the hollow microspheres have a particle size of 1-100 μm and a density of 5-100 kg / m³. 3 Preferably, the hollow microspheres are any one or more of the following: polyacrylic acid hollow microspheres, acrylic hollow microspheres, polystyrene hollow microspheres, silica hollow microspheres, agarose hollow microspheres, chitosan hollow microspheres, and silica hollow microspheres.

[0018] In some embodiments of the present invention, the inorganic salt is any one or more of calcium chloride, potassium chloride, and magnesium chloride.

[0019] In some embodiments of the present invention, the preparation of the blend solution of raw materials includes: mixing inorganic salt with water to obtain an inorganic salt aqueous solution; swelling and dissolving polyvinyl alcohol in the inorganic salt aqueous solution to obtain a polyvinyl alcohol-inorganic salt aqueous solution; adding hollow microspheres to the polyvinyl alcohol-inorganic salt aqueous solution and mixing to obtain a blend solution.

[0020] In some embodiments of the present invention, inorganic salts, additives and water are mixed to obtain an aqueous solution of inorganic salts; the additives include one or more of functional fillers, dyes, foaming agents, humectants and antibacterial agents.

[0021] In some embodiments of the present invention, a polyvinyl alcohol-inorganic salt aqueous solution is heated, and hollow microspheres are added in batches while the solution is still fluid, and the mixture is stirred evenly.

[0022] In some embodiments of the present invention, the defoaming includes three steps: ultrasonic defoaming, puncture defoaming, and pressure filling defoaming. The ultrasonic defoaming process involves heating the blended solution and then ultrasonicating it for 2-120 minutes while maintaining its fluidity. The puncture defoaming process involves puncturing the air bubbles in the blended solution after ultrasonic defoaming. The pressure filling defoaming method involves applying pressure to the blended solution after puncture defoaming to eliminate air bubbles.

[0023] In some embodiments of the present invention, the constant temperature and time water loss treatment includes water loss of 0.5 to 108 h at 10 to 50 °C and 10% to 70% humidity.

[0024] Preferably, the constant temperature and humidity water loss treatment includes water loss for 12 to 72 hours at 10 to 30 ℃ and 30% to 50% humidity.

[0025] Preferably, the constant temperature and humidity dehydration treatment includes dehydration at 30 ℃ and 40% humidity for 12 to 72 hours.

[0026] Preferably, the water loss rate is 10% to 70%, more preferably 20% to 30%.

[0027] In a second aspect, the present invention provides a green polymeric ultralight clay material, which is prepared by the preparation method described in the first aspect.

[0028] In some embodiments of the present invention, the green polymer ultralight clay material exhibits a weight change rate of less than 3% within 140 h.

[0029] A third aspect of the present invention provides the application of the green polymer ultralight clay material described in the second aspect or the green polymer ultralight clay material prepared by the preparation method described in the first aspect as a toy material, cushioning material, heat insulation material, sound insulation material, antibacterial material and / or buoyancy material. In some embodiments of the present invention, the toy is an ultra-light clay toy. The beneficial effects of this invention are as follows: This invention provides a new generation of high-performance, green polymeric ultralight clay material. It uses low-density hollow microspheres as fillers and polyvinyl alcohol gel as a matrix. Utilizing the dual effects of hydration and salt dissolution of inorganic salts, it synergistically regulates the molecular chain behavior and amorphous structure formation under specific dehydration conditions. The green polymeric ultralight clay material provided by this invention is free of chemical cross-linking agents, is environmentally friendly, and possesses high water retention (maintaining softness and plasticity even after exposure to air for over 140 hours), high plasticity, and simple processing. It is expected to overcome the application limitations of existing materials and demonstrate significant application value in areas such as children's play molds and adult stress-relieving toys.

[0030] This invention also provides a method for preparing green polymer ultralight clay materials. Through a unique combination of raw materials and a simplified preparation process, it achieves significant improvements in the safety, performance, and production efficiency of traditional ultralight clay materials. After defoaming the raw material blending solution, a single step of "constant temperature and humidity dehydration treatment" is performed to complete the molding process. Compared with existing technologies that may require complex cross-linking reactions, high-temperature and high-pressure treatments, or energy-intensive periodic mechanical loading and freeze-thaw cycles, this method greatly simplifies the production process, reduces energy consumption and production costs, and improves product consistency. This invention cleverly combines the multifunctional application of inorganic salts with constant temperature and humidity dehydration treatment, successfully preparing a green polymer ultralight clay material that possesses high safety, ultralight texture, excellent flexibility, strong water retention, and good process applicability, comprehensively solving multiple problems related to safety, performance, and preparation cost in existing products. Attached Figure Description

[0031] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0032] Figure 1 The stress-strain curves of the green polymer ultralight clay materials obtained in Examples 1 and 4 of this invention are shown.

[0033] Figure 2 The elastic recovery rate is the value of the green polymer ultralight clay material obtained in Examples 1 and 4 of this invention.

[0034] Figure 3 The rheological curves of the green polymer ultralight clay materials obtained in Examples 1 and 4 of this invention are shown.

[0035] Figure 4 The room temperature stability of the green polymer ultralight clay materials obtained in Example 1 and Comparative Example 1 of this invention is shown.

[0036] Figure 5 The diagram shows the green polymer ultralight clay materials obtained in Example 1 and Comparative Example 2 of this invention placed in water. In Example 1, the addition of hollow microspheres gives it lightweight properties and it floats on the water surface, while in Comparative Example 2, no hollow microspheres are present and it sinks underwater.

[0037] Figure 6 This describes the morphology of the green polymer ultralight clay material obtained in Example 1 of the present invention. Detailed Implementation

[0038] To address the problems of toxicity, water retention, complex plasticity processes, and insufficient research on lightweighting of traditional plastic clays, this invention proposes a green polymer ultralight clay material, its preparation method, and its applications.

[0039] This invention provides a method for preparing a green polymer ultralight clay material. The raw material composition of the green polymer ultralight clay material is: 5-35 wt% polyvinyl alcohol, 5-70 wt% hollow microspheres, 1-40 wt% inorganic salt, and the remainder is water. The preparation method includes: preparing a blending solution of the raw materials, defoaming the blending solution, and then subjecting it to constant temperature and humidity dehydration treatment to obtain the green polymer ultralight clay material. To address the technical bottlenecks in existing technologies, this invention proposes an innovative solution that organically integrates the salt-dissolving effect of inorganic salts, the lightweight properties of hollow microspheres, and the molecular chain network structure of polyvinyl alcohol (PVA), achieving a breakthrough improvement in material performance. First, by introducing inorganic salts into the PVA-hollow microsphere system, the hydration effect of the inorganic salts effectively regulates the water loss kinetics of the mixed solution, enabling controllable water loss under constant temperature and humidity conditions, avoiding the high energy consumption problems of traditional freeze-thaw processes and periodic mechanical loading. Second, the inorganic salts significantly inhibit the crystallization tendency of PVA molecules during water loss through the salt-dissolving effect, resulting in an amorphous, strongly hydrogen-bonded network structure. This characteristic greatly improves the material's flexibility and plasticity, giving it a skin-like "J"-shaped stress-strain curve. Finally, by precisely controlling the order of addition and process parameters, interface optimization and synergistic effects among the three components are achieved, enabling the material to maintain its ultra-lightweight properties (significantly reduced density) while significantly improving its water retention capacity to over 140 hours, far superior to traditional materials. This multi-component, multi-scale collaborative design approach provides a new technical path for the development of polymer ultralight clay materials, and solves the long-standing technical problem of balancing lightweighting with water retention and plasticity.

[0040] In some embodiments of the present invention, the amount of polyvinyl alcohol in the raw material composition of the green polymer ultralight clay material can be selected from the following ranges or any value within the following ranges: 6-35 wt%, 8-35 wt%, 10-35 wt%, 15-35 wt%, 18-35 wt%, 20-35 wt%, 25-35 wt%, 30-35 wt%, 5-30 wt%, 5-20 wt%, 10-30 wt%, 10-20 wt%, 10-15 wt%, 10-17 wt%, 14-20 wt%, 13-18 wt%, 10-16 wt%, 15-16 wt%, etc. In some embodiments of the present invention, the amount of hollow microspheres in the raw material composition of the green polymer ultralight clay material can be selected from the following ranges or any value within the following ranges: 5-70 wt%, 5-60 wt%, 5-50 wt%, 5-40 wt%, 5-30 wt%, 5-20 wt%, 10-70 wt%, 20-70 wt%, 30-70 wt%, 10-60 wt%, 15-60 wt%, 15-50 wt%, 15-40 wt%, 15-30 wt%, 15-20 wt%, 18-23 wt%, 15-25 wt%, etc. In some embodiments of the present invention, the amount of inorganic salt in the raw material composition of the green polymer ultralight clay material can be selected from the following ranges or any value within the following ranges: 1-40 wt%, 1-30 wt%, 1-20 wt%, 1-10 wt%, 10-40 wt%, 10-30 wt%, 10-20 wt%, 15-35 wt%, 20-35 wt%, 22-33 wt%, 10-35 wt%, 10-25 wt%, etc. In some embodiments of the present invention, the green polymer ultralight clay material further includes 0.1-10 wt% additives; the additives include one or more of functional fillers, dyes, foaming agents, humectants, and antibacterial agents. The additives can impart multifunctionality or aesthetic properties to the green polymer ultralight clay material, and the addition of the additives does not affect the original properties of the initial green polymer ultralight clay material.

[0041] The functional fillers include, but are not limited to, at least one of graphene, carbon nanotubes and MXene. Such additives can impart electrical conductivity and other properties to green polymer ultralight clay materials, thereby making the green polymer ultralight clay materials multifunctional.

[0042] The dyes include, but are not limited to, at least one of Congo Red, Methyl Orange, Rhodamine B, Methylene Blue, and Crystal Violet. Such additives give green polymer ultralight clay materials aesthetic appeal and increase their visual value.

[0043] The foaming agent includes, but is not limited to, at least one of sodium dodecyl sulfate, sodium dodecylbenzene sulfonate, sodium α-alkenyl sulfonate, triethanolamine lauryl sulfate, and sodium lauryl polyoxyethylene ether carboxylate. Such additives give the green polymer ultralight clay material better ductility.

[0044] The humectant includes, but is not limited to, at least one of glycerin, propylene glycol, butylene glycol, polyethylene glycol, and sorbitol, which imparts moisturizing properties to the green polymer ultralight clay material.

[0045] The antibacterial agents include, but are not limited to, silver ion antibacterial agents, such as soluble silver compounds like silver nitrate, and nano-sized metallic silver particles. Such additives endow green polymer ultralight clay materials with excellent antibacterial properties.

[0046] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 10-35 wt% polyvinyl alcohol, 5-70 wt% hollow microspheres, 10-40 wt% inorganic salts, and the remainder is water.

[0047] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 10-25 wt% polyvinyl alcohol, 5-50 wt% hollow microspheres, 20-40 wt% inorganic salts, and the remainder is water.

[0048] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol, 20 wt% hollow microspheres, 22 wt% inorganic salt, and the remainder is water.

[0049] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 14 wt% polyvinyl alcohol, 20 wt% hollow microspheres, 22 wt% inorganic salts, and the remainder is water.

[0050] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol, 5 wt% hollow microspheres, 22 wt% inorganic salt, and the remainder is water.

[0051] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol, 20 wt% hollow microspheres, 33 wt% inorganic salts, and the remainder is water.

[0052] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 10-25 wt% polyvinyl alcohol, 5-50 wt% hollow microspheres, 20-40 wt% inorganic salts, 0.1-10 wt% additives, and the remainder is water.

[0053] In some embodiments of the present invention, the raw material composition of the green polymer ultralight clay material is: 10-25 wt% polyvinyl alcohol, 5-50 wt% hollow microspheres, 20-40 wt% inorganic salt, 0.1-10 wt% MXene, and the remainder is water.

[0054] In some embodiments of the present invention, the number average molecular weight of the polyvinyl alcohol is 7,000-200,000, and the degree of alcoholysis is 80-99.9%. Specifically, the polyvinyl alcohol can be selected from grades such as 1799, 2099, 2299, 2499, 2699, or 1788. Polyvinyl alcohol serves as a polymer network matrix material, effectively combining various raw materials.

[0055] In some embodiments of the present invention, the hollow microspheres have a particle size of 1-100 μm and a density of 5-100 kg / m³. 3 The hollow microspheres can be organic or inorganic, including but not limited to any one or more of the following: polyacrylic acid hollow microspheres, acrylic hollow microspheres, polystyrene hollow microspheres, silica hollow microspheres, agarose hollow microspheres, chitosan hollow microspheres, and silica hollow microspheres.

[0056] In some embodiments of the present invention, the inorganic salt is a salt capable of forming hydration with polyvinyl alcohol molecules. For example, the inorganic salt is any one or more of calcium chloride, potassium chloride, and magnesium chloride, preferably calcium chloride. The addition of calcium chloride acts as a water-retaining agent, effectively limiting the water loss and its degree during the preparation of the green polymer ultralight clay material. More importantly, it also inhibits the crystallization behavior of polyvinyl alcohol during the dehydration process, thereby giving the resulting green polymer ultralight clay material superior flexibility and plasticity, and ensuring the long-term stability of the final material.

[0057] In some embodiments of the present invention, the preparation of the blend solution of raw materials includes: mixing inorganic salt with water to obtain an inorganic salt aqueous solution; swelling and dissolving polyvinyl alcohol in the inorganic salt aqueous solution to obtain a polyvinyl alcohol-inorganic salt aqueous solution; adding hollow microspheres to the polyvinyl alcohol-inorganic salt aqueous solution and mixing to obtain a blend solution.

[0058] This invention specifies the order of raw material addition. First, the inorganic salt preferentially dissolves in water, forming a homogeneous aqueous environment with a specific ionic strength. This sets a clear "stage" for the subsequent dissolution of the polymer. When polyvinyl alcohol (PVA) is added to this inorganic salt aqueous solution, the inorganic salt ions preemptively bind with water molecules (hydration). This can, to a certain extent, regulate the swelling rate and degree of the PVA molecular chains, preventing excessive water absorption and entanglement of the PVA molecular chains in the initial stage. This ensures that PVA can fully dissolve in the presence of inorganic salts and form a homogeneous, viscous gel matrix. This homogeneous gel network is the solid foundation for the subsequent support of hollow microspheres.

[0059] In contrast, if all solid raw materials (PVA, inorganic salts, hollow microspheres) are put into water at once, problems such as PVA swelling and clumping, excessively high local concentration of inorganic salts, and hollow microspheres floating or being difficult to wet due to low density are very likely to occur, resulting in uneven dispersion of the components and ultimately affecting the quality of the material.

[0060] In some preferred embodiments, polyvinyl alcohol swells in an inorganic salt solution for 30-720 min.

[0061] In some embodiments of the present invention, inorganic salts, additives and water are mixed to obtain an aqueous solution of inorganic salts; the additives include one or more of functional fillers, dyes, foaming agents, humectants and antibacterial agents.

[0062] In some embodiments of the present invention, a polyvinyl alcohol-inorganic salt aqueous solution is heated, and hollow microspheres are added in batches while the solution remains fluid, and the mixture is stirred thoroughly after each addition. After each addition, the mixture must be stirred sufficiently to ensure that the hollow microspheres are completely wetted and dispersed before adding the next batch. As the volume fraction of hollow microspheres increases, the viscosity of the solution system increases, making it difficult to disperse subsequently added hollow microspheres. To inhibit the aggregation of hollow microspheres, external pressure can be applied to ensure uniform dispersion.

[0063] After obtaining a homogeneous PVA-inorganic salt aqueous solution, hollow microspheres are added in batches, which is crucial for forming a strong interfacial bond. The viscous PVA-inorganic salt aqueous solution can better encapsulate and wet each hollow microsphere. Adding hollow microspheres in batches ensures that each batch of microspheres has enough PVA adhesive to encapsulate it, avoiding direct contact or aggregation of microspheres, thus allowing them to be uniformly distributed as independent filling phases within the PVA three-dimensional network framework. The inorganic salt ions in the solution act as a "bridge" or regulator between the PVA molecular chains and the surface of the hollow microspheres, enhancing the interfacial interaction between the PVA framework and the hollow microsphere filling phase, which helps to form a stable composite structure.

[0064] This step-by-step addition sequence greatly improves the controllability of the entire preparation process, which helps to ensure the stability of the final product performance and batch-to-batch consistency.

[0065] In some preferred embodiments, when adding hollow microspheres to the solution in small amounts multiple times, the stirring time is 5-120 min.

[0066] In some embodiments of the present invention, the defoaming includes three steps: ultrasonic defoaming, puncture defoaming, and pressure filling defoaming. The ultrasonic defoaming process involves heating the blended solution and then ultrasonicating it for 2-120 minutes while maintaining its fluidity. The puncture defoaming process involves puncturing the air bubbles in the blended solution after ultrasonic defoaming. The pressure filling defoaming method involves applying pressure to the blended solution after puncture defoaming to eliminate air bubbles.

[0067] In some embodiments of the present invention, the constant temperature and time water loss treatment includes placing the defoamed blended solution in an environment of 10~50 ℃ and 10%~70% humidity for 0.5~108 h to lose water. Under such water loss conditions, the water loss rate can usually reach 10-70%.

[0068] In some preferred embodiments, the constant temperature and humidity water loss treatment includes water loss for 12 to 72 hours at 10 to 30 ℃ and 30% to 50% humidity. Under such water loss conditions, the water loss rate can typically reach 10 to 50%.

[0069] In some preferred embodiments, the constant temperature and humidity water loss treatment includes water loss at 30°C and 40% humidity for 12 to 72 hours, and the water loss rate can typically reach 20-30% under such conditions.

[0070] In this invention, the term water loss rate refers to the ratio of the mass of water lost during the water loss process to the original mass of the solution, which can be calculated by weighing the solution before and after water loss. For example, if the original mass of the solution is 10 grams and the mass becomes 5 grams after water loss, then the water loss rate is 50%. The present invention also provides a green polymer ultralight clay material, which is prepared by any of the above-mentioned preparation methods.

[0071] The green polymer ultralight clay material described in this invention possesses excellent properties such as good water retention, high plasticity, lightweight, and non-toxicity and environmental friendliness. Furthermore, its preparation process is simple, its composition is straightforward, and it is easy to apply in practical situations. These advantages make it widely applicable in fields such as children's space clay toys, cushioning, heat insulation, sound insulation, and buoyancy materials.

[0072] In some embodiments of the present invention, the green polymer ultralight clay material exhibits a weight change rate of less than 3% within 140 h.

[0073] The present invention also provides an application of the green polymer ultralight clay material described above, or the green polymer ultralight clay material prepared by the preparation method described above, as a toy material, cushioning material, heat insulation material, sound insulation material, antibacterial material and / or buoyancy material. In some embodiments of the present invention, the toy is an ultralight clay toy.

[0074] In summary, this invention utilizes hollow microspheres and polyvinyl alcohol-inorganic salt aqueous solution to prepare green polymer ultralight clay materials. The formula is simple and green, eliminating the potential hazards caused by the addition of chemical crosslinking agents. The preparation process is simple, and a "mud-like" polymer material with both plasticity and environmental friendliness has been successfully prepared.

[0075] This invention uses polyvinyl alcohol hydrogel as a framework to impart mechanical properties to the material; hollow microspheres serve as a filler phase, maintaining system stability through strong interfacial interactions with polyvinyl alcohol; the inorganic salt solution acts as a water-retention agent, preventing the material from cracking in air and controlling the evaporation kinetics of water molecules during the molding process. More importantly, the salt-dissolving effect of the inorganic salt effectively inhibits the crystallization of polyvinyl alcohol during dehydration, and the amorphous network imparts flexibility to the "mud-like" material. Through a dehydration process under specific conditions, this material exhibits good plasticity, stability, and intercomponent adhesion.

[0076] The resulting plastic "mud-like" polymer material not only has strong water retention and excellent molding performance, but also features a simple preparation process, safe and non-toxic components, and is easy to apply in practice. Furthermore, this material is lightweight and environmentally friendly, and can be widely used in various fields such as children's space clay toys and adult stress-relieving toy materials. The various specific technical features described in the above embodiments of the present invention can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. Unless otherwise specified, the numerical range described in this invention includes all values ​​within this range, and also includes the range value formed by any two values ​​within this range. For example, 16% to 20% includes all values ​​between 16% and 20%, and also includes the range value formed by any two values ​​within this range (e.g., 16% and 18.116%) (16% to 18.1%). Different values ​​of the same indicator appearing in all embodiments of this invention can be arbitrarily combined to form a range value.

[0077] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0078] Example 1 This embodiment provides a green polymer ultralight clay material.

[0079] The raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 ), 22 wt% calcium chloride, the remainder being water.

[0080] Preparation methods include: Calcium chloride is mixed with water to obtain a calcium chloride solution.

[0081] Polyvinyl alcohol is placed in a calcium chloride solution to swell and dissolve, resulting in a polyvinyl alcohol-calcium chloride solution.

[0082] In a constant-temperature water bath, when the viscosity of the polyvinyl alcohol-calcium chloride solution significantly decreases and its flowability improves, hollow microspheres are added in small, batches. After each addition, the mixture is thoroughly stirred to ensure the microspheres are completely wetted and dispersed before adding the next batch, thus obtaining a blended solution.

[0083] The blended solution was defoamed. First, ultrasonic defoaming technology was used for preliminary defoaming. Then, the solution that had been preliminarily defoamed was injected into the mold, and residual air bubbles inside were broken by puncture method to achieve the second step of defoaming. Further, circulating pressure was applied to the solution that had completed the first two steps of defoaming to promote material filling and complete the third step of defoaming.

[0084] The defoamed blend solution was subjected to constant temperature and humidity dehydration treatment. Water loss was carried out at 30 ℃ and 40% humidity for 24–36 h, and the solution stabilized after the water loss rate reached 20%–30%.

[0085] Example 2 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that: the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The mixture consisted of 33 wt% calcium chloride and the remainder water. During preparation, water was lost at 30 °C and 10% humidity for 24–36 h, stabilizing after a water loss rate of 20%–25%. The remaining steps were identical to those in Example 1.

[0086] Note: This embodiment increases the calcium chloride content. The high calcium chloride content significantly increases the water retention of the green polymer ultralight clay material. Therefore, the humidity of the dehydration environment is reduced during the preparation process to accelerate water loss.

[0087] Example 3 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that: the raw material composition of the green polymer ultralight clay material is: 14 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The mixture consisted of 22 wt% calcium chloride and the remainder water. During preparation, water was lost at 30 °C and 40% humidity for 24–36 h, stabilizing after a water loss rate of 20%–30%. The remaining steps were identical to those in Example 1.

[0088] Example 4 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 5 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The mixture consisted of 22 wt% calcium chloride and the remainder water. During preparation, water was lost at 30 °C and 40% humidity for 24–36 h, reaching a stable rate of 30%–40%. The remaining steps were identical to those in Example 1.

[0089] Example 5 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000 (degree of alcoholysis 99%), 20 wt% polystyrene hollow microspheres, 22 wt% calcium chloride, and the remainder water. During the preparation process, water was lost at 30 °C and 40% humidity for 24–36 h, and the water loss rate reached 20%–30% before stabilization. The remaining steps were completely consistent with those in Example 1.

[0090] Example 6 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 75000, degree of alcoholysis 88%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The mixture consisted of 22 wt% calcium chloride and the remainder water. During preparation, water was lost at 30 °C and 40% humidity for 24–36 h, reaching a stable rate of 20%–30%. The remaining steps were identical to those in Example 1.

[0091] Example 7 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The mixture consisted of 22 wt% calcium chloride and the remainder water. During preparation, water was lost at 30 °C and 40% humidity for 24–36 h, reaching a stable rate of 20%–30%. The remaining steps were identical to those in Example 1.

[0092] Example 8 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The mixture contained 22 wt% calcium chloride, with the remainder being water. During preparation, water was lost at 30°C and 40% humidity for 24–36 hours, reaching a stable rate of 10%–20%. The remaining steps were identical to those in Example 1.

[0093] Example 9 This embodiment provides a green polymer ultralight clay material, which differs from Embodiment 1 in that the raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The mixture consisted of 22 wt% calcium chloride, 5 wt% MXene, and the remainder was water. During preparation, calcium chloride, MXene, and water were mixed to obtain a calcium chloride solution; the solution was then subjected to water loss at 30 °C and 40% humidity for 24–36 hours, reaching a stable state after a water loss rate of 20%–30%. The remaining steps were identical to those in Example 1.

[0094] Comparative Example 1 This comparative example provides a green polymer ultralight clay material.

[0095] The raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 The rest is water.

[0096] Preparation methods include: Polyvinyl alcohol is placed in water to swell and dissolve, resulting in a polyvinyl alcohol solution.

[0097] In a constant-temperature water bath, when the viscosity of the polyvinyl alcohol solution significantly decreases and its flowability improves, hollow microspheres are added in small, batches. After each addition, the mixture is thoroughly stirred to ensure the microspheres are completely wetted and dispersed before adding the next batch, thus obtaining a blended solution.

[0098] The blended solution was defoamed. First, ultrasonic defoaming technology was used for preliminary defoaming. Then, the solution that had been preliminarily defoamed was injected into the mold, and residual air bubbles inside were broken by puncture method to achieve the second step of defoaming. Further, circulating pressure was applied to the solution that had completed the first two steps of defoaming to promote material filling and complete the third step of defoaming.

[0099] The defoamed blend solution was subjected to constant temperature and humidity dehydration treatment. Water loss was carried out at 30 ℃ and 40% humidity for 24–36 h, reaching a stable rate of 40%–55%.

[0100] Comparative Example 2 This comparative example provides a green polymer ultralight clay material.

[0101] The raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000 (degree of alcoholysis 99%), 22 wt% calcium chloride, the remainder being water.

[0102] Preparation methods include: Calcium chloride is mixed with water to obtain a calcium chloride solution.

[0103] Polyvinyl alcohol is placed in a calcium chloride solution to swell and dissolve, resulting in a polyvinyl alcohol-calcium chloride solution.

[0104] The polyvinyl alcohol-calcium chloride solution was defoamed. First, ultrasonic defoaming technology was used for preliminary defoaming. Then, the solution that had undergone preliminary defoaming was injected into the mold, and residual air bubbles inside were broken by puncture method to achieve the second step of defoaming. Further, circulating pressure was applied to the solution that had completed the first two steps of defoaming to promote material filling and complete the third step of defoaming.

[0105] The defoamed polyvinyl alcohol-calcium chloride solution was subjected to constant temperature and humidity dehydration treatment. Water loss was carried out at 30 ℃ and 40% humidity for 24–36 hours, reaching a stable rate of 30%–40%.

[0106] Comparative Example 3 This comparative example provides a green polymer ultralight clay material.

[0107] The raw material composition of the green polymer ultralight clay material is: 20 wt% polyvinyl alcohol (M... w = 70000, degree of alcoholysis 99%), 20 wt% hollow microspheres (polypropylene hollow microspheres, particle size 25~35 μm, density 60~80 kg / m³) 3 ), 22 wt% calcium chloride, the remainder being water.

[0108] Preparation methods include: Calcium chloride is mixed with water to obtain a calcium chloride solution.

[0109] Polyvinyl alcohol is placed in a calcium chloride solution to swell and dissolve, resulting in a polyvinyl alcohol-calcium chloride solution.

[0110] In a constant-temperature water bath, when the viscosity of the polyvinyl alcohol-calcium chloride solution significantly decreases and its flowability improves, hollow microspheres are added in small, batches. After each addition, the mixture is thoroughly stirred to ensure the microspheres are completely wetted and dispersed before adding the next batch, thus obtaining a blended solution.

[0111] The blended solution was defoamed. First, ultrasonic defoaming technology was used for preliminary defoaming. Then, the solution that had been preliminarily defoamed was injected into the mold, and residual air bubbles inside were broken by puncture method to achieve the second step of defoaming. Further, circulating pressure was applied to the solution that had completed the first two steps of defoaming to promote material filling and complete the third step of defoaming.

[0112] The defoamed blend solution was subjected to constant temperature and humidity dehydration treatment. Water loss was carried out at 55 ℃ and 40% humidity for 24–36 h, and the solution stabilized after the water loss rate reached 35%–45%.

[0113] The density, weight change rate after being placed in air for 140 h, and hand feel of the green polymer ultralight clay materials obtained in the examples and comparative examples were tested. The test results are shown in Table 1.

[0114] Table 1. Results of density, weight change rate, and hand feel smoothness tests

[0115] As shown in Table 1, this invention successfully prepared a series of low-density, high-water-retention (i.e., high-stability) space mud materials by optimizing the formula (especially the combination of calcium chloride and hollow microspheres) and process. Compared with the defective comparative examples, each example showed balanced and superior performance in key aspects. The weight change rate of Comparative Example 1 was as high as 33.1%, far higher than all other samples, and its texture was poor. This indicates that the material lost moisture severely within 140 hours, was extremely prone to cracking, and had very poor water retention. In stark contrast, the weight change rates of Examples 1-9 (all containing 22-33% CaCl2) were all controlled between 1.3% and 6.9%, indicating that calcium chloride can effectively "lock in" the moisture of the material, greatly improving the product's continuous stability and long-term water retention, solving the pain points of traditional environmentally friendly materials such as "poor water retention and easy cracking". The density of Comparative Example 2 was as high as 1.17 g / cm³. 3 The sample with the highest density was [sample number missing]. This makes the material heavier and negates its "ultralight" properties. All examples with added hollow microspheres showed a significant decrease in density (0.37-0.91 g / cm³). 3 (Especially in Examples 1-3 and 6-9, the density is between 0.37 and 0.56 g / cm³.)3 In this process, "ultra-lightweight" was achieved. It is evident that the introduction of hollow microspheres is key to obtaining excellent feel and reducing density. Example 2 optimized the drying process by adjusting humidity (10%), resulting in a final weight change rate as low as 1.3%, making it the example with the best water retention performance. Comparative Example 3, although exhibiting extremely low density and weight change rate, employed extreme high-temperature (55°C) water loss. The significant difference in water loss between the outer surface and interior of the material during this process led to an uneven internal structure and poor feel, making it a less desirable solution. Example 4 achieved a relatively high density (0.91) and a low weight change rate (4.1%) by reducing the hollow microsphere content (5%), demonstrating that performance can be precisely controlled through formulation. The addition of the functional additive (5% MXene) in Example 9 maintained good density (0.47) while also controlling the weight change rate appropriately (4.2%), showcasing the potential for functional expansion.

[0116] As shown in Table 1, this invention, through its core system of polyvinyl alcohol / calcium chloride / hollow microspheres, simultaneously achieves environmental safety (free from toxic crosslinking agents such as borax and glutaraldehyde), excellent water retention / stability (low weight change rate), and a lightweight feel (low density), effectively addressing the high-level market demands for safety, environmental friendliness, and sustainable performance raised in the background art. Furthermore, the data in Table 1 shows that by adjusting the calcium chloride content, hollow microsphere content, and water loss conditions, the density and water retention of the material can be fine-tuned to meet the specific needs of different application scenarios. For example, Example 2 represents the optimal balance point in water retention, while Example 3 shows a better overall balance between density and water retention.

[0117] Figure 1 These are stress-strain curves of the green polymer ultralight clay materials obtained in Examples 1 and 4 of this invention. Figure 1 It can be seen that adjusting the content of hollow microspheres can change the modulus and strength of green polymer ultralight clay material. Compared with Example 4, the sufficient amount of hollow microspheres in Example 1 endows the green polymer ultralight clay material with excellent flexibility.

[0118] Figure 2 This refers to the elastic recovery rate of the green polymer ultralight clay materials obtained in Examples 1 and 4 of this invention. Figure 2 It can be seen that the green polymer ultralight clay material prepared by the present invention has excellent elasticity when the content of hollow microspheres is low, and its deformation rate is small after 90% strain compression; when the content of hollow microspheres increases to a certain amount, as in Example 1, its elasticity decreases significantly and its plasticity is significantly enhanced.

[0119] Figure 3 These are the rheological curves of the green polymer ultralight clay materials obtained in Examples 1 and 4 of this invention. Figure 3It can be seen that when the content of hollow microspheres in the green polymer ultralight clay material is low, G' is greater than G'', and the material exhibits solid-like characteristics similar to a hard gel; in Example 1, G'' is greater than G' in the low-frequency region and G' is greater than G'' in the high-frequency region, and the material exhibits viscoelastic and plastic characteristics similar to a "mud" material.

[0120] Figure 4 The room temperature stability of the green polymer ultralight clay materials obtained in Example 1 and Comparative Example 1 of this invention is measured. Figure 4 It is known that the green polymer ultralight clay material prepared by this invention has excellent water retention properties, which enables it to remain stable at room temperature.

[0121] Figure 5 The images show the green polymer ultralight clay materials obtained in Example 1 and Comparative Example 2 of this invention placed in water. In Example 1, the addition of hollow microspheres imparts lightweight properties to the green polymer ultralight clay material, causing it to float on the water surface. In Comparative Example 2, without hollow microspheres, the material sinks underwater.

[0122] Figure 6 The green polymer ultralight clay material obtained in Example 1 of this invention exhibits excellent plasticity after being pressed, and can be freely molded into various complex shapes.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a green polymer ultra-light clay material, characterized in that, The raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 5-35 wt%, hollow microspheres 5-70 wt%, inorganic salt 1-40 wt%, and the rest is water; The preparation method comprises: preparing a blending solution of raw materials, defoaming the blending solution, and then performing constant temperature and humidity dehydration treatment to obtain the green polymer ultralight clay material.

2. The production method according to claim 1, wherein The green polymer ultralight clay material further comprises 0.1-10 wt% of an auxiliary agent; the auxiliary agent comprises one or more of a functional filler, a dye, a foaming agent, a humectant, and an antibacterial agent; Preferably, the functional filler comprises at least one of graphene, carbon nanotubes, and MXene; Preferably, the dye comprises at least one of Congo red, methyl orange, rhodamine B, methylene blue, and crystal violet; Preferably, the foaming agent comprises at least one of sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, sodium alpha-alkenyl sulfonate, triethanolamine lauryl sulfate, and sodium lauryl alcohol polyoxyethylene ether carboxylate; Preferably, the humectant comprises at least one of glycerol, propylene glycol, butanediol, polyethylene glycol, and sorbitol; Preferably, the antibacterial agent comprises a silver ion antibacterial agent.

3. The production method according to claim 2, wherein The raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 10-35 wt%, hollow microspheres 5-70 wt%, inorganic salt 10-40 wt%, and the rest is water; Preferably, the raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 10-25 wt%, hollow microspheres 5-50 wt%, inorganic salt 20-40 wt%, and the rest is water; Preferably, the raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 20 wt%, hollow microspheres 20 wt%, inorganic salt 22 wt%, and the rest is water; Preferably, the raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 14 wt%, hollow microspheres 20 wt%, inorganic salt 22 wt%, and the rest is water; Preferably, the raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 20 wt%, hollow microspheres 5 wt%, inorganic salt 22 wt%, and the rest is water; Preferably, the raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 20 wt%, hollow microspheres 20 wt%, inorganic salt 33 wt%, and the rest is water; Preferably, the raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 10-25 wt%, hollow microspheres 5-50 wt%, inorganic salt 20-40 wt%, auxiliary agent 0.1-10 wt%, and the rest is water; Preferably, the raw material composition of the green polymer ultralight clay material is: polyvinyl alcohol 10-25 wt%, hollow microspheres 5-50 wt%, inorganic salt 20-40 wt%, MXene 0.1-10 wt%, and the rest is water.

4. The production method according to claim 1, wherein The number average molecular weight of the polyvinyl alcohol is 7000-200000, and the alcoholysis degree is 80-99.9%; Preferably, the hollow microspheres have a particle size of 1-100 μm and a density of 5-100 kg / m 3 Preferably, the hollow microspheres are any one or more of polyacrylic acid hollow microspheres, acrylic hollow microspheres, polystyrene microspheres, silica gel hollow microspheres, agarose hollow microspheres, chitosan hollow microspheres, and silica hollow microspheres. Preferably, the inorganic salt is any one or several of calcium chloride, potassium chloride, and magnesium chloride.

5. The production method according to claim 1, wherein The blending solution of the prepared raw material comprises: mixing the inorganic salt with water to obtain an inorganic salt aqueous solution; swelling and dissolving polyvinyl alcohol in the inorganic salt aqueous solution to obtain a polyvinyl alcohol-inorganic salt aqueous solution; adding the hollow microspheres into the polyvinyl alcohol-inorganic salt aqueous solution and mixing to obtain the blending solution; Preferably, the inorganic salt, the auxiliary agent and water are mixed to obtain an inorganic salt aqueous solution; the auxiliary agent comprises one or more of a functional filler, a dye, a foaming agent, a moisturizing agent and an antibacterial agent; Preferably, the polyvinyl alcohol-inorganic salt aqueous solution is heated, and the hollow microspheres are added in batches under the condition that the polyvinyl alcohol-inorganic salt aqueous solution has fluidity, and stirred uniformly.

6. The production method according to claim 1, wherein The defoaming comprises three steps of ultrasonic defoaming, puncture defoaming and pressure filling defoaming; The ultrasonic defoaming is that the blending solution is heated and ultrasonically treated for 2-120 min under the condition that the blending solution has fluidity; The puncture defoaming is that the bubbles in the blending solution after the ultrasonic defoaming are punctured; The pressure filling defoaming is that pressure is applied to the blending solution after the puncture defoaming to eliminate the bubbles.

7. The production method according to claim 1, wherein The constant-temperature and constant-time water loss treatment comprises water loss for 0.5-108 h under the condition of 10-50 ℃ and 10%-70% humidity; Preferably, the constant-temperature and constant-humidity water loss treatment comprises water loss for 12-72 h under the condition of 10-30 ℃ and 30%-50% humidity; Preferably, the constant-temperature and constant-humidity water loss treatment comprises water loss for 12-72 h under the condition of 30 ℃ and 40% humidity. Preferably, the water loss rate is 10%-70%, preferably 20%-30%.

8. A green polymer ultra-light clay material, characterized in that, The green polymer ultralight clay material is prepared by the preparation method of any one of claims 1-7.

9. The green polymer ultra-lightweight clay material of claim 8, wherein the clay material has a bulk density of 0.2 g / cm3 or less. The weight change rate of the green polymer ultralight clay material is less than 3% within 140 h.

10. Application of the green polymer ultralight clay material of claim 8 or 9 or prepared by the preparation method of any one of claims 1-7 as a toy material, a cushioning material, a thermal insulation material, a sound insulation material, an antibacterial material and / or a buoyancy material. Preferably, the toy is an ultralight clay toy.

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