Self-healing gel-type composite composition based on thermoplastic elastomer and method for producing the same

Abstract

The present invention relates to a self-restoring gel-type composite composition comprising a thermoplastic elastomer thickener and a vegetable oil, and a method for manufacturing the same. The self-restoring gel-type composite composition according to the present invention provides durability that allows it to maintain its original physical properties even after repeated physical damage due to the interaction between the thermoplastic elastomer thickener and the vegetable oil, and provides the characteristic that the self-restoring process can occur repeatedly.

Description

Technology Field

[0001] The present invention relates to a self-restoring gel-type composite composition comprising a thermoplastic elastomer thickener and vegetable oil, and a method for manufacturing the same. Background Technology

[0002] Self-restoring or self-healing materials are special substances capable of repairing damaged areas on their own without external intervention, and they are attracting attention in fields such as cosmetics and pharmaceuticals. In particular, in the cosmetics industry, the ability to recover to its original state even if deformation or breakage occurs during use is recognized as a crucial factor in improving product durability and usability.

[0003] The repair mechanisms of self-restoring or self-healing materials are broadly classified into microcapsule systems, hydrogen bonding, reversible chemical bonding, and external stimulus-responsive types. Microcapsule systems utilize microcapsules containing a healing agent dispersed within the material; upon damage, the capsules rupture to release the agent and repair the damaged area, but this method has the drawback of being limited to one-time repair. Self-restoring materials utilizing hydrogen bonding employ supramolecular polymer technology that uses intermolecular attractive forces to allow damaged parts to re-bond, but this method suffers from the problem of reduced mechanical strength even after repair. Reversible chemical bonding utilizes chemical bonds that can be reformed after physical destruction. External stimulus-responsive types enable autonomous repair in response to specific environmental conditions, such as heat, light, or pH changes, but they have limitations due to their dependence on environmental conditions. The aforementioned self-restoring or self-healing mechanisms require high-temperature processing of over 200°C and have limitations such as dependence on plasticizers, one-time repair, and restricted repair locations.

[0004] Thermoplastic elastomers (TPEs) are block copolymer materials that exhibit rubber-like elasticity while possessing thermal plasticity, and they have unique self-healing properties. When an elastomer is crushed or its surface is torn by external forces, its internal network structure temporarily deforms, but over time, the molecules return to their original positions and the damaged areas are repaired. Materials based on such thermoplastic elastomers provide excellent flexibility and elastic recovery.

[0005] However, thermoplastic elastomer materials require high-temperature processing during manufacturing, which leads to high energy consumption and prolonged production times. Additionally, the need for high levels of plasticizing oil can cause issues with increased product tackiness.

[0006] Against this background, the inventors devised the present invention to provide a composition having a rapid recovery speed and enhanced recovery characteristics through a composite composition based on a thermoplastic elastomer and utilizing vegetable oil. Prior art literature

[0007] Korean Patent Publication No. 10-2020-0046737 The problem to be solved

[0008] The present invention aims to provide a composition that secures structural stability through the interaction of a thermoplastic elastomer thickener and a vegetable oil, possesses repeated self-restoring power even under multiple physical damages, and has rapid recovery power. Furthermore, it aims to provide a composition having physical properties suitable for cosmetic formulations by utilizing the characteristic that gel formation is possible through the complete dissolution of vegetable oil. means of solving the problem

[0009] To solve the above problem, the present invention provides a self-restoring gel-type composite composition comprising a thermoplastic elastomer thickener and vegetable oil. Effects of the invention

[0010] The self-restoring gel-type composite composition according to the present invention has durability and structural stability that can maintain its original physical properties even after repeated physical damage due to the interaction between a thermoplastic elastomer thickener and vegetable oil, and has the effect of restoring itself at a rapid speed as the self-restoring process occurs repeatedly even after multiple physical damages.

[0011] In addition, by utilizing the characteristic that gel formation is possible through the complete dissolution of vegetable oil, a composition suitable for cosmetic formulations can be provided. Brief explanation of the drawing

[0012] Figure 1 shows a state in which a self-restoring gel-type composite composition according to one embodiment of the present invention is placed in a container and stabilized. FIG. 2 illustrates the process of verifying the self-restoring ability of a self-restoring gel-type composite composition according to one embodiment of the present invention. FIG. 2(a) shows that tearing and crushing of the surface of the composition occurred due to external physical damage. FIG. 2(b) shows that the damaged composition was restored to its original structure and physical properties on its own without additional external intervention, confirmed at 1 minute, 5 minutes, 7 minutes, and 10 minutes after damage, respectively. Specific details for implementing the invention

[0013] Hereinafter, various embodiments of the present invention are described with reference to the accompanying drawings. The present invention is not limited to specific embodiments and should be understood to include various modifications, equivalents, and / or alternatives of the embodiments of the present invention. In relation to the description of the drawings, similar reference numerals may be used for similar components.

[0014] In this document, expressions such as "have," "can have," "include," or "can include" refer to the existence of the relevant feature (e.g., numerical values, functions, actions, or components, etc.) and do not exclude the existence of additional features.

[0015] In this document, expressions such as “A or B,” “at least one of A or / and B,” or “one or more of A or / and B” may include all possible combinations of items listed together. For example, “A or B,” “at least one of A and B,” or “at least one of A or B” may refer to cases including (1) at least one A, (2) at least one B, or (3) both at least one A and at least one B.

[0016] As used in this document, the expression "configured to" may be replaced, depending on the context, with, for example, "suitable for," "having the capacity to," "designed to," "adapted to," "made to," or "capable of." The term "configured to" does not necessarily mean "specifically designed to."

[0017] The terms used in this document are used merely to describe specific embodiments and are not intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as generally understood by those skilled in the art described in this document. Terms used in this document that are defined in general dictionaries may be interpreted as having the same or similar meaning as they have in the context of the relevant technology, and are not to be interpreted in an ideal or overly formal sense unless explicitly defined in this document. In some cases, even terms defined in this document may not be interpreted to exclude the embodiments of this document.

[0018] The embodiments disclosed in this document are presented for the purpose of explaining and understanding the disclosed technical content and are not intended to limit the scope of the invention. Accordingly, the scope of this document should be interpreted to include all modifications or various other embodiments based on the technical concept of the invention.

[0019] Hereinafter, preferred embodiments of the present invention will be described in detail. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, and should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0020] Therefore, it should be understood that the configurations of the embodiments described in this specification are merely some of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention, and that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0021] Throughout the specification, when a part is described as “comprising” a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0022] The present invention will be described in detail below.

[0024] According to one embodiment of the present invention, a self-restoring gel-type composite composition comprising a thermoplastic elastomer thickener and a vegetable oil is provided. Each component is described in detail below.

[0025] The above thermoplastic elastomer is a polymer material that possesses both rubber and plastic properties. It has the characteristic of melting upon heating to allow processing into various shapes, and recovering its properties as an elastic body upon cooling. The above thermoplastic elastomer thickener is compatible with non-polar or medium-polar oils and can form a compound capable of thermal deformation at 80 to 100°C. The above thermoplastic elastomer thickener comprises amorphous and rigid domains and soft and flexible chains, and has a structure in which amorphous and rigid domains, soft and flexible chains, and amorphous and rigid domains are repeated. Upon melting, the distance between the amorphous and rigid domains increases and they separate, and during the cooling process after melting, the distance between the amorphous and rigid domains decreases again, allowing the structure to be restored to its original state.

[0026] The above vegetable oil is an oil component extracted from plants and combines with a thermoplastic elastomer thickener to form a self-restoring gel. The above vegetable oil can be trapped between the soft, flexible chains of the thermoplastic elastomer thickener to form an interpenetrating 3D network structure and can form a stable gel structure.

[0027] The self-restoring property described above refers to the characteristic of a composition to restore itself to its original structure and physical properties without additional external intervention after receiving external physical damage (crushing, surface tearing, etc.). Self-restoring property can be realized through a process in which the molecular structure rapidly rearranges over time after deformation, with vegetable oil trapped between the amorphous rigid domains and soft flexible chains of the thermoplastic elastomer acting as a medium. The self-restoring property of the gel-type composite composition of the present invention can occur repeatedly even with multiple physical damages, thereby significantly improving the durability and service life of the composition.

[0028] The gel type described above refers to a semi-solid state formed by the interaction of a thermoplastic elastomer thickener and vegetable oil, maintaining its shape at room temperature and possessing constant elasticity and viscosity. The gel type is characterized by an interpenetrating 3D network structure in which the amorphous rigid domains of the thermoplastic elastomer thickener act as physical crosslinking points, and vegetable oil is trapped between soft flexible chains by 75% to 90%. Unlike conventional cosmetic formulations, the gel type composite composition exhibits excellent self-restoring properties and mechanical stability, and can be applied to various cosmetic formulations.

[0029] The above thermoplastic elastomer thickener is a hydrogenated styrene / butadiene copolymer, a hydrogenated styrene-ethylene / butadiene-styrene copolymer (SEBS), a hydrogenated styrene-isoprene-styrene copolymer (SIS), a hydrogenated styrene-ethylene / propylene-styrene copolymer (SEPS), a hydrogenated styrene-isobutylene-styrene copolymer (SIBS), and a high vinyl content It may include, but is not limited to, one or more selected from the group consisting of High Vinyl Content Hydrogenated Styrene-Butadiene-Styrene Copolymer (High Vinyl SEBS) and HDI / Trimethylol Hexyllactone Crosspolymer.

[0030] The above vegetable oil may include, but is not limited to, one or more selected from the group consisting of jojoba oil, almond oil, coconut oil, canola oil, rice bran oil, sesame oil, avocado oil, walnut oil, sunflower oil, soybean oil, macadamia oil, olive oil, and octyldodecanol.

[0031] The weight ratio of the thermoplastic elastomer thickener and the vegetable oil may be 1:8 to 48. Specifically, the weight ratio may be 1:10 to 40, 1:10 to 35, or 1:10 to 25. More specifically, the weight ratio may be 1:11 to 25. If the content of the vegetable oil is below the above numerical range, the oil may not be sufficiently trapped between the soft and flexible chains of the thermoplastic elastomer, resulting in incomplete gel formation. Additionally, due to a lack of oil medium, the self-restoring ability to return to the original state after external deformation is reduced, and as the proportion of the elastomer increases, the formulation may become hard and flexibility may decrease. If the content of the vegetable oil exceeds the above numerical range, the structural stability of the gel may be reduced, and the shape may not be maintained. Furthermore, stability may be reduced due to phase separation during long-term storage, and the user experience may be degraded as stickiness increases.

[0032] The above thermoplastic elastomer thickener comprises amorphous rigid domains and soft flexible chains, and vegetable oil is trapped between the soft flexible chains, and the vegetable oil trapping ratio within the soft flexible chains may be 75 to 90%. Due to the non-polar or medium-polar characteristics of the vegetable oil, it can be completely bonded to the structure of the thermoplastic elastomer, and due to the long carbon chain structure of the vegetable oil, it can be stably trapped between the soft flexible chain structures of the thermoplastic elastomer to form a physical bond. If the vegetable oil trapping ratio within the soft flexible chains is less than 75%, the self-restoring ability is very high, but the hardness is high, making it unsuitable for use as a cosmetic composition; if the trapping ratio exceeds 90%, the structure becomes unstable due to oil exudation, and the self-restoring efficiency may decrease.

[0033] According to one embodiment of the present invention, a cosmetic composition comprising the self-restoring gel-type composite composition is provided.

[0034] According to one embodiment of the present invention, a method for preparing a self-restoring gel-type composite composition is provided, comprising the steps of: melting a thermoplastic elastomer thickener at 80 to 100°C to induce separation between amorphous rigid domains; adding vegetable oil to the melted thermoplastic elastomer thickener to encapsulate vegetable oil between the soft flexible chains of the thermoplastic elastomer thickener; and cooling the mixture of the thermoplastic elastomer thickener containing the encapsulated vegetable oil to 25 to 40°C to reduce the distance between amorphous rigid domains and form a 3D network structure.

[0035] The step of melting the thermoplastic elastomer thickener at 80 to 100°C to induce separation between amorphous rigid domains is a process of applying thermal energy to the molecular structure of the thermoplastic elastomer to cause a structural change. The thermoplastic elastomer is composed of amorphous rigid domains and soft flexible chains, and when heat of 80 to 100°C is applied, the thermoplastic fixed rings deform, weakening the physical bonds between the amorphous rigid domains and causing them to separate from each other. At this stage, as molecular mobility increases, the structure of the thermoplastic elastomer becomes open. In particular, at approximately 100°C, polar selective bonding is activated, transitioning to a state where interaction with vegetable oil is possible.

[0036] The step of adding vegetable oil to the molten thermoplastic elastomer thickener to encapsulate vegetable oil between the soft flexible chains of the thermoplastic elastomer thickener is a process of adding vegetable oil to the molten elastomer to induce molecular-level interactions. In this process, vegetable oil molecules penetrate into and are encapsulated between the soft flexible chains of the thermoplastic elastomer. In particular, triglyceride-based vegetable oils (jojoba oil, almond oil, coconut oil, etc.) have high encapsulation efficiency and can achieve complete dissolution and gel formation with the elastomer. On the other hand, synthetic oils or silicone oils hardly form a gel with the thermoplastic elastomer. At this stage, the optimal encapsulation ratio of vegetable oil within the soft flexible chains is 75 to 90%, and high self-restoring properties can be achieved within this range.

[0037] The step of cooling the thermoplastic elastomer thickener mixture containing the vegetable oil to 25 to 40°C to reduce the distance between amorphous rigid domains and form a 3D network structure is a process of stabilizing the structure of the thermoplastic elastomer oil composite through the removal of thermal energy. During the cooling process, the amorphous rigid domain portions that were separated at high temperatures come closer together again; at this time, the vegetable oil trapped between the soft flexible chains acts as a medium, forming a stable interpenetrating 3D network structure. This structure is fixed by forming physical crosslinking points in the range of 25 to 40°C, and the final characteristics of the self-healing gel are completed. In particular, the reduction in the distance between amorphous rigid domains can serve as a key mechanism for providing a restoring force that attempts to return to the original state even after deformation caused by external forces.

[0038] The method may further include a step of heating the vegetable oil prior to the step of adding vegetable oil to the molten thermoplastic elastomer thickener to encapsulate the vegetable oil between the soft, flexible chains of the thermoplastic elastomer thickener. The step of heating the vegetable oil may involve heating the vegetable oil to 95°C to melt it.

[0039] The self-restoring gel-type composite composition of the present invention may be included in a cosmetic composition in an amount of 0.01 to 50 weight%, specifically 0.01 to 40 weight%.

[0040] The cosmetic composition of the present invention may further comprise any conventional cosmetic ingredient selected from additional ingredients commonly used in cosmetics, e.g., thickeners, dispersants, fragrances, fillers, preservatives, antiseptics, neutralizing agents, sweeteners, vitamins, free-radical scavengers, metal ion chelating agents, functional ingredients, colorants, conditioning agents, oils, moisturizers, and mixtures thereof. A person skilled in the art may select any additional ingredient and / or the amount thereof so that the advantageous properties of the composition according to this specification are not adversely affected or are substantially affected by the expected addition.

[0041] The cosmetic composition of the present invention may be a cosmetic raw material composition that can be used in the manufacture of cosmetics. In addition, the cosmetic composition may be a cosmetic composition having a final cosmetic formulation.

[0043] The present invention will be described in more detail below through examples. These examples are intended solely to explain the present invention more specifically, and it will be obvious to those skilled in the art that the scope of the present invention is not limited by these examples according to the gist of the present invention.

[0045] Examples and Comparative Examples

[0046] Self-healing gel-type composite compositions according to Examples 1 to 3 and Comparative Examples 1 to 3 were prepared using the components and content listed in [Table 1] below. Specifically, jojoba oil was heated to 95°C and melted (S1). Hydrogenated styrene / butadiene copolymer was slowly added to the jojoba oil while stirring to separate amorphous rigid domains, thereby increasing molecular mobility and preparing a mixture (S2). The mixture was cooled to 25°C to reduce the distance between amorphous rigid domains, thereby forming a 3D network structure and stabilizing the gel structure (S3).

[0047] ingredient Thermoplastic elastomer thickener (weight%) (A) Vegetable oil (weight%) (B) Weight ratio of A and B Hydrogenated Styrene / Butadiene Copolymer Jojoba oil Example 1 5 95 1:19 Example 2 4 96 1:24 Example 3 8 92 1:11.5 Comparative Example 1 2 98 1:49 Comparative Example 2 12 88 1:7.3 Comparative Example 3 14 86 1:6.1

[0049] Experimental Example 1

[0050] The gel formation, gel strength, complete recovery, and payoff of the self-restoring gel-type composite compositions according to Examples 1 to 3 and Comparative Examples 1 to 3 were evaluated.

[0051] (1) Gel formation evaluation method

[0052] 5 g of each composition sample was injected into a container and stabilized at 25° for 24 hours, then the container was tilted at a 45° angle and maintained for 5 minutes.

[0053] The gel formation evaluation criteria are as follows: ○: No sample flow; △: Partial sample flow; ×: Complete sample flow.

[0054] (2) Gel strength evaluation method

[0055] The gel strength of the self-healing gel-type composite compositions according to Examples 1 to 3 and Comparative Examples 1 to 3 was evaluated. Each composition sample was uniformly filled into a flat container of the same specifications (diameter 30 mm, height 10 mm), stabilized at 25°C for 24 hours, and then evaluated by the same evaluator. The gel strength was evaluated by pressing the center of the gel with the tip of an index finger for 5 seconds with a constant pressure equivalent to 500 g (prior training was conducted by pressing a finger on an electronic scale to standardize the pressure).

[0056] The gel strength evaluation criteria are as follows: Excellent: Immediate restoration after pressure, no fingerprint traces; High: Restoration within 10 seconds after pressure release, fine fingerprints; Upper-Medium: Restoration within 30 seconds after pressure release, distinct fingerprints; Medium: Restoration within 3 minutes after pressure release, clearly visible fingerprints; Lower-Medium: Traces persisting for more than 3 minutes after pressure release, distinct deformation.

[0057] According to the above gel strength evaluation criteria, the highest strength is such that, due to its rubber-like hardness, the composition does not stick even when applied with a finger or spatula, and it cannot be easily spread on the skin.

[0058] (3) Evaluation of complete restorability (recovery of physical deformation)

[0059] Samples of the compositions according to Examples 1 to 3 and Comparative Examples 1 to 3 were uniformly filled into flat containers of the same specifications (diameter 30 mm, height 10 mm), and a blunt tool was used to press the sample surface to a depth of 5 mm. The damaged area was inspected immediately after impact, after 5 minutes, and after 10 minutes to visually check and record the degree of restoration.

[0060] The criteria for evaluating full recovery are as follows: Excellent: Over 90% recovery within 5 minutes; High: 70-90% recovery within 5 minutes; Upper-Medium: 70-90% recovery within 10 minutes; Medium: 50-70% recovery within 10 minutes; Lower-Medium: Less than 50% recovery after 10 minutes.

[0061] (4) Payoff evaluation

[0062] Payoff evaluation is an assessment of how well the composition is transferred when the product is rubbed on the skin, puff, brush, or fingers, that is, the amount and uniformity actually applied to the skin. Five or more trained evaluators were selected, and the surface of the composition samples according to Examples 1 to 3 and Comparative Examples 1 to 3 was rubbed once with a constant pressure using the evaluator's index finger, and the payoff of the composition was evaluated based on the amount and texture of the sample transferred to the finger.

[0063] The evaluation criteria are as follows: Possible: Delivery of an appropriate amount to the finger, uniform distribution; Small Amount Possible: Delivery of a small amount to the finger; Not Possible: Almost no residue remains on the finger and no composition is delivered at all.

[0064] The results are shown in [Table 2].

[0065] Gel formation status Gel strength Complete restoration Payoff note Example 1 ○ middle slander possible Example 2 ○ Middle-low Middle-low possible Example 3 ○ award award Small quantities available Comparative Example 1 × - - liquid Comparative Example 2 ○ Best award It won't work Comparative Example 3 ○ Best award It won't work Not completely dissolved

[0066] Synthesizing the results of Experimental Example 1, Examples 1 through 3 all demonstrated good gel formation. In particular, Example 1 exhibited balanced characteristics, showing appropriate gel strength (medium), excellent complete recovery (medium-high), and payoff (possible), allowing an appropriate amount to adhere to the fingers during actual use. Example 2 showed soft gel strength (medium-low) and recovery (medium-low), and its payoff was excellent, similar to Example 1. Example 3 displayed excellent gel strength (high) and recovery (high), but because the gel was somewhat hard, the amount adhering to the fingers during actual use was less compared to Example 1. On the other hand, Comparative Example 1 remained in a liquid state as no gel formation occurred at all, while Comparative Examples 2 and 3 showed very excellent gel strength and recovery (best, high), but their practicality was poor as they were excessively hard, resulting in almost no adhering to the fingers (unsatisfactory). Examples 1 through 3 demonstrated the most suitable characteristics as self-healing gel-type composite compositions. .

[0068] Experimental Example 2

[0069] The hardness (g-force) of the compositions according to Examples 1 to 3 and Comparative Examples 1 to 3 was measured.

[0070] The hardness of the above self-healing gel-type composite composition was measured using the indentation function (conical instrument) of a rheometer. Measurements were taken at a temperature of 25°C using a standard metal needle with a diameter of 1 mm (1Φ). Specifically, the compositions of Examples 1 to 3 and Comparative Examples 2 to 3 were filled into a flat container, stabilized at 25°C for one day, and then a metal needle was inserted 0.5 to 1.0 mm, and the force required for insertion was measured using an instrument.

[0071] At this time, the experiment was not conducted on formulations such as highly fluid liquids that are not solids, as measurement was impossible.

[0072] The results measured according to the above are reflected in Table 3, and in Table 3, a higher penetration value indicates harderness.

[0073] Penetration (1mm (1Φ)) Longitude analysis Example 1 42 Medium firmness Example 2 34 Slightly soft Example 3 67 stiffness Comparative Example 1 Unmeasurable (liquid) Unmeasurable (liquid) Comparative Example 2 160 Very hard due to excessive hardness Comparative Example 3 235 Very hard due to excessive hardness

[0074] As a result of measuring the hardness of the compositions according to Examples 1 to 3 and Comparative Examples 1 to 3, it can be confirmed that Comparative Example 1 is unsuitable as a gel-type composite composition because it has high flowability and fails to maintain its shape at all. It can be confirmed that Comparative Examples 2 and 3 have high hardness and lack flexibility and self-restoring properties of the gel-type composite composition. On the other hand, it can be confirmed that the compositions according to Examples 1 to 3 have a hardness sufficient to maintain a gel form, possess durability, and exhibit excellent self-restoring properties even under external force.

Claims

Claim 1 A self-restoring gel-type composite composition comprising a thermoplastic elastomer thickener and a vegetable oil, wherein the content of the thermoplastic elastomer thickener is 4 to 8 weight%, the content of the vegetable oil is 92 to 96 weight%, and the thermoplastic elastomer thickener comprises a hydrogenated styrene / butadiene copolymer. Claim 2 delete Claim 3 A self-restoring gel-type composite composition according to claim 1, wherein the vegetable oil comprises one or more selected from the group consisting of jojoba oil, almond oil, coconut oil, canola oil, rice bran oil, sesame oil, avocado oil, walnut oil, sunflower oil, soybean oil, macadamia oil, olive oil, and octyldodecanol. Claim 4 A self-restoring gel-type composite composition according to claim 1, wherein the weight ratio of the thermoplastic elastomer thickener and the vegetable oil is 1:8 to 48. Claim 5 A cosmetic composition comprising a self-restoring gel-type composite composition according to any one of claims 1 and 3 to 4.

Images