Latex coagulant containing polymer silk, rubber product therewith and molding method

Abstract

To provide a latex coagulant containing polymer silk for producing rubber products excellent in mechanical strength, a rubber product using the latex coagulant and a method for molding using the latex coagulant.SOLUTION: Aqueous solutions containing 30 to 60% by mass of calcium chloride and 2 to 10% by mass of polymer silk dispersed and dissolved therein were used as a latex coagulant to solve the above problems. By coagulating latex using this latex coagulant, rubber products with excellent mechanical strength were produced. The shaping of the rubber products can be achieved by applying this latex coagulant to the object, or by applying a material impregnated with it to the object, and then bringing the latex into contact with the object.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a latex coagulant containing polymeric silk, a rubber product using the same, and a method for producing a shape. [Background technology]

[0002] A known method for creating rubber products such as rubber masks, hand molds, and special makeup involves applying latex to a plaster mold. Commonly used latexes include liquid latex containing ammonia and cream latex without ammonia. Cream latex without ammonia is used for applications such as direct application to the skin, while liquid latex containing ammonia is often poured into a plaster mold without being used on the skin. Some latexes also contain alcohol, which is used by volatilizing the alcohol or allowing it to be absorbed into the plaster and harden.

[0003] In the manufacture of rubber products, improvement in mechanical strength is sometimes required. For example, Patent Document 1 proposes a ceramic glove mold for manufacturing rubber gloves with excellent mechanical strength and no pinholes, and a surface treatment agent for use therewith. Patent Document 1 proposes a surface treatment agent for generating a dry coating film with a crack pattern on the surface of a bisque-fired ceramic glove master, which is a compound of a glass-forming inorganic component and a high drying shrinkage component. The ceramic glove master has a textured surface, and the textured pattern is applied to the surface of the bisque-fired ceramic glove master. The crack pattern of the surface treatment agent generated by drying is baked to form the textured pattern on the surface of the glove mold. Rubber gloves with excellent mechanical strength and no pinholes or cracks are manufactured using the glove mold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-104737 Summary of the Invention [Problem to be solved by the invention]

[0005] Various conventional latexes are used for various purposes, but if the latex has excellent mechanical strength, it can be used for more various purposes, can withstand long-term use, and is thought to have the advantages of improving the total cost.

[0006] In this regard, the present inventors have been conducting research into the use of latex, aiming to develop high-strength fibers using polymeric silk, such as those used by Spider-Man. In the process, they have focused on latex containing silk, and have discovered a new, unprecedented latex coagulant containing polymeric silk, as well as highly functional rubber products and new molding techniques using the same.

[0007] The present invention has been made based on the above findings, and its object is to provide a latex coagulant containing polymeric silk for producing rubber products with excellent mechanical strength, a rubber product using the latex coagulant, and a method for creating a shape using the latex coagulant. [Means for solving the problem]

[0008] (1) The latex coagulant according to the present invention is characterized in that it is an aqueous solution in which 30 to 60% by mass of calcium chloride and 2 to 10% by mass of polymeric silk are dispersed and dissolved.

[0009] According to this invention, the latex coagulant is an aqueous solution in which calcium chloride and polymeric silk are dispersed and dissolved within the above ranges. Therefore, the rubber product obtained by coagulating latex with this latex coagulant contains polymeric silk, which enhances mechanical strength. Polymeric silk gels appropriately and is stable in aqueous solution, making it easy to apply and fix to the target object. As a result, the polymeric silk can be evenly distributed over the entire surface of the target object, ensuring uniform mechanical properties of the resulting rubber product. Furthermore, the polymeric silk adheres to the surface of the rubber product produced using the latex coagulant, resulting in a good texture and improved product image.

[0010] (2) The rubber product according to the present invention is characterized in that it is a rubber product produced by coagulating latex using the latex coagulant according to the present invention.

[0011] According to this invention, the produced rubber product contains polymeric silk contained in the latex coagulant, so the polymeric silk contained in the rubber product can provide the rubber product with high strength. In addition, the polymeric silk contained in the rubber product is easily fixed on the surface of the rubber product, so the obtained rubber product can be prevented from cracking or breaking on the surface, achieving higher strength.

[0012] (3) One embodiment of the method for producing a shape according to the present invention is characterized in that after the latex coagulant according to the present invention is applied to an object, or after an impregnating material impregnated with the latex coagulant according to the present invention is attached to the object, latex is brought into contact with the object to form a rubber product.

[0013] According to this invention, by using a latex coagulant, a rubber product can be easily formed on an object.

[0014] (4) Another embodiment of the method for producing a shape according to the present invention is characterized in that after latex is brought into contact with an impregnating material impregnated with the latex coagulant according to the present invention, another impregnating material identical or substantially identical to the impregnating material is placed on top of the latex, and a load is applied from one or both sides to form a rubber product.

[0015] According to this invention, the impregnated material impregnated with the latex coagulant sandwiches the latex from both sides under load, so that the obtained rubber product can be a shaped part of a rubber product having excellent mechanical strength. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a latex coagulant containing polymeric silk for producing rubber products with excellent mechanical strength, a rubber product using the latex coagulant, and a method for creating a shape using the latex coagulant.

[0017] In particular, since the latex coagulant is an aqueous solution in which calcium chloride and polymeric silk are dispersed and dissolved, the rubber product obtained by coagulating latex with this latex coagulant contains polymeric silk, which increases mechanical strength. Polymeric silk gels appropriately in aqueous solution and is stable, making it easy to apply and fix to the target object. As a result, the polymeric silk can be evenly distributed over the entire surface of the target object, ensuring uniform mechanical properties of the resulting rubber product. Furthermore, the polymeric silk adheres to the surface of rubber products made using the latex coagulant, resulting in a good texture and improved product image. [Brief explanation of the drawings]

[0018] [Figure 1] 6 is a photograph illustrating an example of a procedure for obtaining a fingerprint mask using the modeling method according to the present invention. [Figure 2] 10 is a photograph showing an example of a fingerprint mask obtained by the modeling method according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] The latex coagulant, rubber product, and modeling method according to the present invention will be described in detail based on the following embodiments. Note that the following embodiments are preferred examples of the present invention and should not be construed as being limited to these embodiments.

[0020] [Latex coagulant] The latex coagulant according to the present invention is characterized in that it is an aqueous solution in which 30-60% by mass of calcium chloride and 2-10% by mass of polymeric silk are dispersed and dissolved. In this invention, the aqueous solution in which calcium chloride and polymeric silk are dispersed and dissolved in the above ranges is used as the latex coagulant, so that the rubber product obtained by coagulating latex with the latex coagulant contains polymeric silk, which can increase the mechanical strength.

[0021] Each component will be described in detail.

[0022] (Calcium chloride) Calcium chloride is contained in the latex coagulant, which is an aqueous solution, and acts as a latex coagulant and curing agent. Calcium chloride is contained in the latex coagulant at a ratio of 30 to 60% by mass. By being contained within this range, calcium chloride can function favorably as a latex coagulant and curing agent. If the calcium chloride content is less than 30% by mass, the calcium chloride content may be too low and may not function adequately as a latex coagulant or curing agent. If the calcium chloride content exceeds 60% by mass, the calcium chloride content may be too high, which may result in aggregation or crystallization of the calcium chloride itself. By maintaining the calcium chloride content within this preferred range, more stable coagulation and curing can be achieved, improving and stabilizing the characteristic properties of rubber products.

[0023] (polymeric silk) Polymeric silk is contained in the latex coagulant, which is an aqueous solution, and is incorporated into the coagulated rubber product to enhance the mechanical strength of the rubber product. Polymeric silk is contained in the latex coagulant at a ratio of 2 to 10% by mass. By containing the polymeric silk within this range, the polymeric silk can function as described above. If the polymeric silk content is less than 2% by mass, the polymeric silk content may be too low and may not function sufficiently. If the polymeric silk content exceeds 10% by mass, the polymeric silk content may be too high and may not be uniformly incorporated. Adjusting the polymeric silk content within this range allows for control of the viscosity of the resulting latex coagulant. Specifically, increasing the polymeric silk content within this range increases the viscosity of the latex coagulant, preventing it from easily flowing when applied to an object. On the other hand, decreasing the polymeric silk content within this range decreases the viscosity of the latex coagulant, making it easier to apply to an object. The preferred content of polymeric silk is 2 to 5 mass %. By setting the content within this preferred range, the polymeric silk can be contained more uniformly in the latex coagulant, which has the advantage of imparting stable mechanical strength to rubber products produced by coagulating latex with this latex coagulant, as well as improving the ease of applying and fixing the latex coagulant to the target object.

[0024] Polymeric silk gels appropriately and is stable in the aqueous latex coagulant solution. By incorporating it in this gel state into the latex coagulant, the viscosity of the latex coagulant is increased, making it easier to apply and fix to the target object, as explained in the previous paragraph. As a result, the polymeric silk can be evenly distributed over the entire surface of the target object, ensuring uniform mechanical properties of the resulting rubber product. Furthermore, the polymeric silk adhered to the surface of rubber products made using the latex coagulant offers the advantage of a good texture and improved product image.

[0025] "Appropriate gelation" refers to the state of polymeric silk in the latex coagulant (a stable state of existence). This state allows for easy viscosity adjustment by fine-tuning the content ratio when applying the latex coagulant, depending on the application and target object. Therefore, it is desirable for latex coagulants containing polymeric silk to be in this moderate gelation state. The state of polymeric silk adhering to the surface of a rubber product can be confirmed by magnifying and observing the surface of the resulting rubber product or by analyzing the surface components using an electron microscope, etc.

[0026] Polymeric silk, also known as silk fibroin, contains a type of fibrous protein that can be purified from cocoons produced by silkworms. Polymeric silk can be purified by known methods, such as those exemplified in WO2006 / 101223. Polymeric silk is characterized by a high proportion of glycine, alanine, serine, and tyrosine, and may be derived from organisms classified into the order Lepidoptera, Hymenoptera, or Araneae. Polymeric silk may also be obtained by genetic recombination technology, and is not particularly limited.

[0027] (latex coagulant) The latex coagulant is an aqueous solution containing the aforementioned calcium chloride and polymeric silk. Such a latex coagulant is heated to disperse and dissolve the polymeric silk. The heating temperature is not particularly limited, but can be, for example, approximately 80 to 100°C. The polymeric silk dispersed in the latex coagulant is moderately gelled and stabilized, making it easy to apply and fix to an object. Fixation refers to the ability of the latex coagulant to be easily retained on the object after application. As a result, the latex coagulant can be evenly retained over the entire surface of the object, and the polymeric silk contained in the latex coagulant can be evenly distributed over the object.

[0028] [Rubber products] The rubber product according to the present invention is a rubber product produced by coagulating latex using the latex coagulant according to the present invention. As is well known, latex refers to a colloidal aqueous dispersion of rubber, and the type is not particularly limited, but examples include natural latex such as natural rubber and artificial latex such as silicone rubber. The produced rubber product contains the polymeric silk contained in the latex coagulant, which can provide the rubber product with high strength. Furthermore, the polymeric silk contained in the rubber product is easily fixed to the surface of the rubber product, preventing cracks and breaks at the surface of the resulting rubber product, thereby achieving higher strength.

[0029] Examples of rubber products include, but are not limited to, rubber masks, hand molds, special makeup, and the like described in the Background Art section, as well as foam rubber, dipped products (rubber gloves, finger cots, condoms, shoe insoles, leather linings, etc.), products for textile processing, paper processing (calendars, wrapping paper, etc.), construction sealants, elastic cement, ABS resin base polymers, road paving, adhesives, rubber threads for golf balls, general-purpose rubber sheets (crepe rubber, candy-filled rubber, etc.), etc. Products requiring mechanical strength are particularly preferred as they can better demonstrate the effects of the present invention.

[0030] [Modeling method] One embodiment of the object-forming method according to the present invention is a method for forming a rubber product by applying the latex coagulant according to the present invention to an object or by attaching an impregnating material impregnated with the latex coagulant according to the present invention to the object and then contacting the object with latex. This object-forming method can easily form a rubber product on the object by using the latex coagulant.

[0031] Another embodiment of the method for producing a rubber product according to the present invention is a method in which latex is brought into contact with an impregnating material impregnated with the latex coagulant according to the present invention, and then another impregnating material identical or substantially identical to the impregnating material is placed on top of the latex, and a load is applied from one or both sides to form a rubber product. In this method, the impregnating materials impregnated with the latex coagulant sandwich the latex from both sides under load, so that the resulting rubber product can be a shaped part of a rubber product with particularly excellent mechanical strength.

[0032] In the two types of modeling methods described above, the target object is not particularly limited. For example, if the target object is a face, hand, finger, etc., the method can be preferably applied as a modeling method for rubber product objects such as rubber masks, handprints, special makeup, etc. Furthermore, various targets can be applied depending on the examples of rubber products described above, and the method can be preferably applied as a modeling method for such rubber product objects.

[0033] In the two modeling methods described above, the application may be direct application or indirect application via an application device or application member, and is not particularly limited. The impregnating material is not particularly limited as long as it can be impregnated or soaked with the latex coagulant, and examples include nonwoven fabric, thin gauze, and wettable or impregnated paper. The latex coagulant containing gelled polymer silk can be adjusted to a viscosity that allows it to be applied or transferred to a target object or target site, which has the advantage that it can be applied or transferred to materials such as plastics that do not wet or impregnate.

[0034] The two model creation methods described above allow for the creation of complex objects (such as face masks) more easily and precisely than conventional processes, resulting in the exceptional effect of making it possible to create detailed objects (such as fingerprint masks) that were previously impossible to create.

[0035] An example of how a typical face mask is made is to apply plaster dissolved in an alcohol solution to the face, wait for the plaster to dry, and then remove it from the face. Next, the plaster is poured into the facial mold that has been removed from the face to create a plaster mold. Latex is then applied to the plaster mold thus created. The plaster to which the latex has been applied absorbs the alcohol contained in the latex, causing the latex to dry, and the dried latex can be peeled off to obtain the desired rubber product. The modeling method according to the present invention is characterized by achieving the effects described above, unlike these conventional methods.

[0036] (Example) FIG. 1 is a photograph explaining an example of the procedure for producing a fingerprint mask by the molding method according to the present invention, and FIG. 2 is a photograph showing an example of a fingerprint mask produced by the molding method according to the present invention. In the example of FIGS. 1 and 2, first, latex coagulant is placed in the palm of the hand (FIG. 1(A)), the latex coagulant is spread on the palm (FIG. 1(B)), and then latex is applied on top of that (FIG. 1(C)). A finger, which is the object to be molded, is pressed against the latex coagulant (FIG. 1(D)), and then the mask is dried to form a rubber product (fingerprint mask) (FIGS. 1(E)(F)). The obtained fingerprint mask, as shown in FIGS. 2(A)(B), is a thin, fine fingerprint mask film with excellent mechanical strength that could not be produced by conventional methods, and therefore the fingerprint pattern does not easily disappear, making it a stable fingerprint mask.

[0037] 1 and 2, a method for forming a fingerprint mask has been described, but the present invention is not limited to this and can also be used for manufacturing and forming other rubber products. In particular, the forming method according to the present invention has the special advantage that it does not require the creation of a mold, thereby reducing the amount of work required and enabling the precise reproduction of fingerprints and the like.

[0038] These characteristics promise promising applications for the rubber products of the present invention. For example, in addition to rubber products such as rubber masks, handprints, and special makeup, the present invention offers exceptional advantages, such as promising new applications for thin-film products like the fingerprint masks and similar products, as well as safe, inexpensive, high-quality, and strong, realistic reconstruction materials for missing body parts, such as skin substitutes (artificially engineered wound dressings), prosthetic limbs (fingers, hands, noses, ears, etc.), and breast reconstruction (artificial breasts, pads, nipples, etc.). Furthermore, even with regard to the intended development goal (e.g., the development of high-strength fibers like Spider-Man's thread), the present invention can be applied to create high-strength fibers with high mechanical strength, which can be used in products requiring high strength and high shear stress (high cutting force). In particular, because such high-strength fibers are also elastic, they can be used in dangerous work clothing, bulletproof vests, and other products that can utilize this elasticity. [Example]

[0039] The present invention will be described in detail below with reference to experimental examples.

[0040] [Experiment 1] (Test Method) Tensile tests were conducted in accordance with JIS K6251:2017, "Determination of tensile properties of vulcanized and thermoplastic rubber." Test pieces were prepared by applying a latex coagulant consisting of 3.7% by mass of refined polymeric silk dispersed in a calcium chloride aqueous solution (50% by mass of calcium chloride) and drying the solution to form a 0.8 mm thick test sheet. A control test piece was prepared by applying a latex coagulant containing no refined polymeric silk to the sheet and drying it to form a 0.8 mm thick comparative test sheet. The polymeric silk used in this experiment was polymeric silk (product name: ma33, average molecular weight: 130,000, freeze-dried fibroin) manufactured by Shearing International Science.

[0041] The test sheets and comparative test sheets were punched with a punching blade into No. 6 dumbbell shapes (compliant with JIS K6251) (parallel part width: 4.0±0.1 mm, parallel part thickness: 2.0±0.2 mm, gauge length: 20±0.5 mm). A universal tension and compression testing machine (manufacturer: Instron, model number: 68TM-30) was used, and the test conditions were initial length: 35 mm, test speed: 200 mm / min, number of test pieces: 5 each, and test room temperature: 23±2°C.

[0042] (Test results) The results of the tensile properties of the test sheet are shown in Table 1, and the results of the tensile properties of the comparative test sheet are shown in Table 2. The "tensile elongation at break" was determined from the total elongation of the test piece.

[0043] [Table 1]

[0044] [Table 2]

[0045] From the above results, the maximum tensile load of the test sheet according to the present invention was more than twice as large as that of the comparative test sheet, resulting in a greater-than-expected improvement in strength. Furthermore, the tensile elongation at break of the test sheet according to the present invention was also significantly larger than that of the comparative test sheet in four-fifths of cases, demonstrating that the test sheet exhibited high strength yet large elongation. Observation of the test sheet and the comparative test sheet revealed that the polymeric silk was fixed to the surface of the test sheet, which appears to prevent the rubber from tearing at the surface.

Claims

1. A latex coagulant characterized by being an aqueous solution in which 30 to 60% by mass of calcium chloride and 2 to 10% by mass of polymeric silk are dispersed and dissolved.

2. A rubber product, characterized in that it is a rubber product produced by coagulating latex using the latex coagulant according to claim 1.

3. A method for creating a shape, comprising: applying the latex coagulant according to claim 1 to an object; or attaching an impregnating material impregnated with the latex coagulant according to the present invention to the object; and then contacting the object with latex to form a rubber product.

4. A method for producing a rubber product, comprising the steps of: bringing latex into contact with an impregnating material impregnated with the latex coagulant according to claim 1; placing another impregnating material identical or substantially identical to the impregnating material on top of the latex; and applying a load from one or both sides of the impregnating material to form a rubber product.

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