Material composition and methods for its production

Abstract

Material composition, comprehensive: i) A hydroxyl-terminated polymer crosslinked by a boron compound, wherein the hydroxyl-terminated polymer is at least one composed of polyvinyl alcohol (PVA) and hydroxyl-terminated silicone oil; and ii) Thermoplastic with a melting point below 100°C.

Description

field of technology

[0001] The invention relates to the field of classroom play and modeling materials and in particular to a material composition and a method for their production. Current state of the art

[0002] Classroom play and modeling materials include Play-Doh, modeling clay, super-lightweight clay, etc. These inventions have been used for toys for over 30 years. However, Play-Doh has an unpleasant odor and contains preservatives that can linger on the hands because it's sticky; it's also difficult to hold its shape. Modeling clay is very liquid and therefore not easy to mold. Super-lightweight clay shrinks after drying because its water content is over 40%.

[0003] WO 2013 / 127989 A1 describes a self-healing elastomer material comprising at least a) a cross-linked diorganopolysiloxane with terminal hydroxyl groups, functionalized as a borate ester, and b) a polymer or bitumen. Several methods for producing the self-healing elastomer materials and their uses are also described.

[0004] From CN111808391A, a polyvinyl alcohol plastic is known which is suitable for garbage bags, preservation films, seedling trays, express packaging, frozen food packaging, soluble adhesive tapes, temporary waterproofing materials, and the like. The manufacture of this polyvinyl alcohol plastic comprises the following steps: preparing a mixture of 100 parts polyvinyl alcohol, 5-40 parts plasticizer, 5-20 parts biodegradable high-molecular-weight polymer, 0.1-5 parts crosslinking agent, and 0.1-5 parts lubricant; stirring the mixture at high speed until a temperature of 100-130 °C is reached; and extruding and granulating in an extrusion and granulation unit at an extrusion and granulation temperature of 160-200 °C. Technical task and solution to the task

[0005] The invention is based on the objective of providing a non-sticky, low-water-content and highly elastic material composition that is easy to shape.

[0006] This problem is solved by a material composition according to claim 1 and by a method for its production according to claim 8. Specific embodiments of the invention are the subject of further claims.

[0007] The material composition of the invention consists of a hydroxyl-terminated polymer, namely at least one made of polyvinyl alcohol (PVA) and hydroxyl-terminated silicone oil, which is cross-linked by a boron compound that makes the material stretchable and non-sticky. A thermoplastic is used to further increase the stretchability, which can also reduce the water content of the material composition and thus facilitate shaping. Brief description of the drawings Fig. Figure 1 shows a flowchart of the process for producing the material composition in one embodiment; Fig. Figure 2 shows a flowchart of the process for producing the material composition in a further embodiment. Embodiments of the invention

[0008] For better understanding, the invention is described in more detail with reference to the accompanying drawings. The preferred embodiments of the invention are presented below. However, the invention can be implemented in many different forms and is not limited to the embodiments described here. Rather, the purpose of providing these embodiments is to ensure a thorough and complete understanding of the invention.

[0009] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as they are usually understood by a person skilled in the art. The terms used in this description serve only to describe specific embodiments and not to limit the invention. The term "and / or" used herein indicates all combinations of one or more of the related listed objects.

[0010] A material composition according to the invention comprises i) hydroxyl-terminated polymer crosslinked by a boron compound; and ii) thermoplastics with a melting point below 100°C.

[0011] A hydroxyl-terminated polymer reacted with boron at high temperature to form a cross-linked compound (i.e., a hydroxyl-terminated polymer cross-linked by a boron compound). This boron-cross-linked hydroxyl-terminated polymer is present in a flexible, kneadable material (such as modeling clay, super-lightweight clay, etc.), such material can directly serve as a component of the material composition of the invention. A boron-cross-linked hydroxyl-terminated polymer can make the material composition stretchable and non-sticky.

[0012] The hydroxyl-terminated polymer consists of at least one polyvinyl alcohol (PVA) and one hydroxyl-terminated silicone oil. PVA is used to produce the water-soluble material composition; hydroxyl-terminated silicone oil is used to produce the oil-soluble material composition.

[0013] To increase the extensibility of the material composition and facilitate its shaping, a thermoplastic is incorporated so that the material composition tends to stay together and retain its shape for a long time after forming. It should be understood that the thermoplastics are plastics with a low melting point. In this context, preferably low-melting-point plastics with a melting point below 100°C are used to facilitate shaping the material composition. It is conceivable that any plastic with a low melting point could be used in this invention.

[0014] The thermoplastic is preferably polycaprolactone (CAS number 24980-41-4, melting point 40-60°C).

[0015] In a preferred embodiment, the thermoplastic content in the material composition is 1–60 wt.%. Particularly preferably, the thermoplastic content in the material composition is 5–60 wt.%. The addition of thermoplastic improves the elongation behavior of the material composition. Thanks to this improved elongation behavior, the material composition tends to hold its shape more readily and can retain its form for a long time after shaping.

[0016] To prevent the material composition from "melting" and returning to its original viscosity after some time, a density-reducing filler is added. However, a high content of density-reducing filler leads to a material composition that is unstable, hard-ductile, and difficult to shape. In a preferred embodiment, the material composition still contains 1-10% by weight of density-reducing filler.

[0017] For health and safety reasons, the boron content must not be too high. However, if the material composition does not contain thermoplastics, a high proportion of boron is required. The addition of thermoplastics reduces the boron content of the material composition. In a preferred embodiment, if the material composition is water-soluble, the boron content is less than 0.1 wt.%, e.g., 0.07–0.09 wt.%. If the material composition is oil-soluble, the boron content is 0.6–0.8 wt.%, and the soluble boron is less than 1200 ppm.

[0018] Fig. Figure 1 shows a flowchart of the process for producing the material composition in an exemplary embodiment. The process for producing the material composition comprises: 1) Add the hydroxyl-terminated polymer to the mixer and maintain the temperature at 60°C; 2) Add the boric acid to the mixer; 3) Mix and heat to 130°C for 2 hours; 4) Cool to 60°C; 5) Add the thermoplastic to the mixer; 6) Mix and cool.

[0019] In a preferred embodiment, the method further optionally includes adding the density-reducing filler to the mixer between steps 5) and 6).

[0020] Fig. Figure 2 shows a flowchart of the process for producing the material composition in a further embodiment. The process for producing the material composition comprises: 1) Dissolving PVA in water at a temperature of 60°C and cooling to room temperature; 2) Mixing PVA solution with boron to form PVA gel; 3) Adding the density-reducing filler and thermoplastic; 4) Mix and cool.

[0021] The invention is explained in more detail below in connection with specific exemplary embodiments.

[0022] The material composition comprises two forms, which are referred to below as thermoplastic modeling clay 1 (oil-soluble / never dry) and thermoplastic modeling clay 2 (water-soluble / air-dry).

[0023] First, we compare super-lightweight clay and thermoplastic modeling clay 2 (water-soluble) of the invention as follows: A) Ingredient of the super-light clay (in wt. -%) 1) Density-reducing filler 2-4 wt.%; 2) PVA 7-10 wt.%; 3) Water 40-50 wt.%; 4) Boron 0.5-0.9 wt.% (SVHC); 5) Others; where the "others" in A) can be glycerin and cornflour. In some embodiments, it can be 1-20 wt% glycerin and 1-20 wt% cornflour. B) Ingredient of thermoplastic modeling clay 2 (water-soluble) (in wt. -%) 1) Density-reducing filler 4-6%; 2) PVA 7-10 wt.%; 3) Water 20-30 wt.%; 4) Thermoplastic 40-50 wt.%; 5) Boron 0.07-0.09 wt.% (less than 0.1 wt.% to comply with the SVHC Regulation); 6) Others; where the “others” in B) can be glycerin and cornflour. In some embodiments, it can be 1-20 wt% glycerin and 1-20 wt% cornflour.

[0024] The thermoplastic modeling clay 2 (water-soluble) has the following advantages: 1) Drying rate: The drying rate is faster (drying time is halved) because the water content in thermoplastic modeling clay 2 is reduced (by 50%). Air drying of the super-lightweight clay takes two days, while drying of thermoplastic modeling clay 2 (water-soluble) takes only one day. 2) The shrinkage rate is reduced from 40% to 20% due to the low water content. After drying, the super-lightweight clay shrinks by 40%, while the thermoplastic modeling clay 2 (water-soluble) shrinks by less than 20% after drying. 3) The boron content will be reduced from 0.5 wt.% to less than 0.1 wt.%. Boron is a Substance of Very High Concern (SVHC) and is prohibited in the EU; it must be below 0.1 wt.%.

[0025] Boron plays an important role in the formulation for stabilizing the entire system. For thermoplastic modeling clay 2 (water-soluble), 0.1% boron is sufficient for stabilization. 4) Formation of the low-density thermoplastic modeling clay 2 (water-soluble). Too high a percentage of the density-reducing filler increases the hardness of the final product. Thermoplastics can reduce the hardness, so that the final product made from thermoplastic modeling clay 2 (water-soluble) has a lower density than normal superkaolin.

[0026] We then compare the bouncy putty, the low-density putty, and the thermoplastic modeling clay 1 (oil-soluble) of the invention as follows: C) Ingredients of the Bouncing Putty (in wt. %) 1) Silicone oil 80-95 wt.%; 2) Boron content 1.5-5 wt.% (soluble boron is above 1200ppm and has failed in the toy regulation EN71 part 3); 3) Others; where the "others" in C can be glycerin and cornflour. In some embodiments, it can be 1-20 wt% glycerin and 1-20 wt% cornflour. D) Ingredients of the low-density putty (in wt. %) 1) Density reducing filler 2-6 wt.%; 2) Silicone oil 60-90 wt.%; 3) Glycerin 2-5% wt; 4) Boron 1.2-4 wt.% (soluble boron exceeds 1200 ppm and does not comply with the toy regulation EN71 Part 3); 5) Others; where the "others" in D) can be cornmeal. In some embodiments, it can be 1-20% by weight cornmeal. E) Ingredients of thermoplastic modeling clay 1 (oil-soluble) (in wt. -%) 1) Density-reducing filler, less than 4%; 2) Silicone oil 40-60 wt.%; 3) Thermoplastic 40-50 wt.%; 4) Boron 0.6-0.8 wt.% (soluble boron is below 1200ppm and complies with the toy regulation EN71 Part 3); 5) Other; where the "others" in E) may be glycerin and cornflour. In some embodiments, it may be 1-20 wt% glycerin and 1-20 wt% cornflour.

[0027] The thermoplastic modeling clay 1 (oil-soluble) has the following advantages, 1) Melting: Modeling clay melts within 1-3 minutes. Thermoplastic modeling clay 1 (oil-soluble) does not melt for several weeks. 2) Thermoplastic modeling clay 1 (oil-soluble) is easy to shape. Low-density putty is not suitable for shaping. Its hardness is too high if the proportion of density-reducing filler is too high. Finally, it is difficult for children to play with because the finished product is too hard. The hardness of low-density putty can be reduced by adding glycerin or by decreasing the proportion of density-reducing filler. However, adding glycerin makes the low-density putty sticky, and reducing the density-reducing filler makes it melt. 3) The boron content is reduced from 1.2–5 wt.% to less than 0.9 wt.%. Only thermoplastic modeling clay 1 (oil-soluble) complies with the toy standard EN71 Part 3.

[0028] The exemplary embodiments described above represent only some embodiments of the invention, which are described in detail below. It should be noted that a person skilled in the art can derive from the foregoing description the other variants and improvements, which also fall within the scope of protection of the invention, without departing from the core idea of ​​the invention. Therefore, the scope of protection of the invention is defined solely by the accompanying claims.

Claims

[1] Material composition, including: i) A hydroxyl-terminated polymer crosslinked by a boron compound, wherein the hydroxyl-terminated polymer is at least one composed of polyvinyl alcohol (PVA) and hydroxyl-terminated silicone oil; and ii) Thermoplastic with a melting point below 100°C. [2] Material composition according to claim 1, characterized by that the thermoplastic is polycaprolactone. [3] Material composition according to claim 1 or 2, characterized by , that the thermoplastic content in the material composition is 1-60 percent by weight. [4] Material composition according to claim 1 or 2, characterized by that the thermoplastic content in the material composition is 5-60 percent by weight. [5] Material composition according to any one of claims 1 to 4, characterized by that the material composition still contains 1-10 percent by weight of a density-reducing filler. [6] Material composition according to any one of claims 1 to 5, characterized by that the material composition is water-soluble and that the boron content in the material composition is less than 0.1%. [7] Material composition according to any one of claims 1 to 5, characterized by that the material composition is oil-soluble and the boron content in the material composition is 0.6-0.8%. [8] Method for producing the material composition according to any one of claims 1 to 7, comprising: - Addition of component i) hydroxyl-terminated polymer, namely at least one made of polyvinyl alcohol (PVA) and hydroxyl-terminated silicone oil cross-linked by a boron compound, and component ii) thermoplastic with a melting point below 100°C; - Mixing component i) and component ii) to obtain the mixture. [9] Method according to claim 8, characterized by , that the procedure further includes: - Add a density-reducing filler to the mixture and mix at room temperature.

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