Superfine seaweed powder modified PBT cosmetic brush filament and preparation method thereof

Abstract

The application relates to the field of new cosmetic tooling fiber materials, in particular to superfine seaweed powder modified PBT cosmetic brush silk and a preparation method thereof. The brush silk comprises the following components in parts by weight: PBT 95-100 parts, seaweed powder 2-4 parts, propyl triethoxysilane isocyanate 0.6-1.2 parts, calcium stearate 0.4-0.6 parts, polyether ester amide 5-15 parts, polyhexamethylene guanidine hydrochloride 0.2-0.4 parts and titanium dioxide 0.05-0.1 parts; the particle size of the seaweed powder is 4-5 mu m. By adding superfine seaweed powder in the formula, the fiber fineness and softness are greatly improved, and the rough friction feeling of common filling brush silk is eliminated; meanwhile, the powder adsorption and locking capacity of the cosmetic powder is improved, the flying powder is reduced, and the makeup is uniform and comfortable; by adding polyether ester amide and polyhexamethylene guanidine hydrochloride in the formula, the antistatic and antibacterial functions are exerted in the PBT matrix without interference, and the synergistic effect of 'one dose of antistatic and one dose of antibacterial' is realized.

Description

Technical Field

[0001] This application relates to the field of new chemical fiber materials for beauty tools, specifically to an ultrafine seaweed powder modified PBT makeup brush bristle and its preparation method. Background Technology

[0002] Makeup brush bristles are the fibrous material that makes up the brush head of a makeup brush, and they are the core component of a makeup brush. Makeup brushes include various types such as eyeshadow brushes, blush brushes, contour brushes, eyebrow brushes, and lip brushes, and the performance requirements of the bristles vary depending on the purpose of the makeup brush.

[0003] Currently, makeup brush bristle materials are mainly divided into two categories: animal hair and synthetic hair. Animal hair includes sheep wool, horsehair, squirrel hair, snow fox hair, and weasel hair, etc.; synthetic hair is mainly made from polybutylene terephthalate (PBT). PBT monofilaments have the characteristics of high strength, good elasticity, fatigue resistance, and solvent resistance, and are often used in the field of tapered filaments for makeup brushes.

[0004] Animal hair (such as squirrel hair, goat hair, and mink hair) has a natural scaly structure on its surface, giving it excellent powder-grabbing ability and a soft, skin-friendly feel. However, the limited availability of animal hair raw materials leads to high costs. Animal hair brushes are typically expensive, limiting their widespread adoption in the mass market. Animal hair is mainly composed of keratin and other substances, making it prone to bacterial growth during production and use. Bacteria can consume the hair, degrading its performance and shortening its lifespan. Furthermore, the bacteria can contaminate cosmetics that come into contact with it, potentially causing skin diseases. Animal hair also swells and deforms easily when it absorbs water, making it even more susceptible to bacterial growth in humid environments.

[0005] While PBT synthetic brush bristles offer advantages such as stable resilience, water resistance, and low cost, conventional PBT synthetic bristles have a smooth surface and lack the scaly structure characteristic of animal hair, resulting in a stiffer feel. When used in makeup brushes, the smooth surface cannot effectively absorb powder cosmetics (such as loose powder and blush), exhibiting significantly lower powder absorption compared to animal hair. Furthermore, synthetic bristle fibers have fewer and unevenly distributed scales on their surface, leading to poor powder pickup and difficulty in applying makeup. Additionally, their powder-carrying power is generally poor, resulting in uneven powder application and insufficient makeup adherence.

[0006] Common materials like PBT have insulating properties, and when brush bristles rub against skin, cosmetic powder, or packaging, they accumulate static electricity. This static electricity causes powder to fall off the brush (powder fly) or the bristles to clump together. Furthermore, PBT bristles are prone to static electricity, leading to problems like bristle sticking and tangling during production, severely impacting production efficiency and finished product shaping.

[0007] Regular PBT bristles do not possess antibacterial properties. While synthetic bristles reduce bacterial growth to some extent, their antibacterial performance is still insufficient. After use, a large number of bacteria can accumulate on the surface of the bristles during storage, posing a hygiene risk for makeup brushes that come into direct contact with skin and makeup products.

[0008] Therefore, there is an urgent need to improve the preparation method of cosmetic brush bristles. While retaining the advantages of PBT such as stable resilience, water resistance, and low cost, it is necessary to solve the defects such as skin irritation, poor powder picking ability, serious static electricity, and lack of antibacterial properties. The goal is to develop a modified PBT cosmetic brush bristle that combines the excellent user experience of animal hair with the stable supply and hygiene and safety of synthetic hair. Summary of the Invention

[0009] To address the challenge of developing a modified PBT cosmetic brush bristle that combines the superior user experience of animal hair with a stable supply and hygiene safety of synthetic hair, this application provides an ultrafine seaweed powder modified PBT cosmetic brush bristle and its preparation method.

[0010] In the first aspect, this application provides an ultrafine seaweed powder modified PBT cosmetic brush bristle, employing the following technical solution: A type of ultrafine seaweed powder modified PBT cosmetic brush bristles, characterized by comprising the following components in parts by weight: The composition includes 95-100 parts PBT, 2-4 parts seaweed powder, 0.6-1.2 parts propyltriethoxysilane isocyanate, 0.4-0.6 parts calcium stearate, 5-15 parts polyether ester amide, 0.2-0.4 parts polyhexamethylene guanidine hydrochloride, and 0.05-0.1 parts titanium dioxide; the seaweed powder has a particle size of 4-5 μm.

[0011] By adopting the above technical solution, this invention uses 3000-mesh ultrafine seaweed powder (particle size 4-5μm) as a modified filler. When seaweed powder is ground to 3000 mesh, it has an extremely large specific surface area. During melt spinning, the seaweed powder particles are uniformly dispersed within the PBT matrix and partially exposed on the fiber surface, constructing a fine and uniform micron-level uneven structure on the fiber surface. Traditional inorganic fillers (such as calcium carbonate and talc) tend to form large protrusions on the fiber surface due to their sharp particle edges and uneven dispersion, resulting in a rough, gritty, and prickly feel. In contrast, 3000-mesh ultrafine seaweed powder has an extremely small particle size and its surface contains abundant hydrophilic groups such as hydroxyl (-OH), possessing a certain degree of natural lubricity. At the interface between the seaweed powder and PBT, due to the bridging effect of the coupling agent, the seaweed powder particles are coated with organic long chains, transforming the feel from a rough, "hard, granular" sensation to a lubricating, "velvety" feel. Meanwhile, the micron-level concave-convex structure creates a micro-texture similar to natural animal hair in terms of touch, which greatly improves the smoothness and softness of the fiber when it comes into contact with the skin, eliminates the rough friction of ordinary filling brush bristles, and achieves a high-end skin-friendly effect with zero skin irritation.

[0012] The micron-level uneven structure on the fiber surface significantly increases the contact area and physical adhesion between the brush bristles and the makeup powder. When the brush bristles come into contact with the makeup powder, the powder particles are captured in the "micro-pits" of the uneven structure, thereby enhancing the powder adsorption and retention capacity. At the same time, seaweed powder itself has certain oil-absorbing and moisturizing properties, which can absorb the oil components in the makeup, further enhancing the adhesion stability of the powder. This structural design makes the powder less likely to fall during makeup application (reducing fallout), and the powder is released evenly and adheres well to the skin surface, reducing the need for multiple powder pick-ups. Furthermore, since the uneven structure formed by the seaweed powder on the fiber surface is not obtained through destructive means such as chemical corrosion, the fiber structure itself remains intact, so the resilience and water resistance of the brush bristles are not affected.

[0013] This invention uses polyether ester amide as an antistatic agent and polyhexamethylene guanidine hydrochloride (PHMG) as an antibacterial agent. The two work together to achieve excellent antistatic and antibacterial effects.

[0014] Polyether ester amides belong to the polyether block amide (PEBA) copolymer family and are a type of permanent polymeric antistatic agent. Polyether ester amides exert their effect by forming a three-dimensional ionic conductive network within the PBT matrix. Specifically, the polyether segments in the polyether ester amide molecule are hydrophilic, enabling the formation of continuous conductive channels within the matrix, allowing static charge to leak and dissipate rapidly. This conductive network does not depend on the migration of antistatic agent molecules to the surface; therefore, its antistatic effect is permanent and does not disappear with time, washing, or surface abrasion. Furthermore, its effect is unaffected by ambient humidity, maintaining excellent static dissipation capabilities even under extremely low humidity conditions.

[0015] The antibacterial mechanism of polyhexamethylene guanidine hydrochloride: Polyhexamethylene guanidine hydrochloride is an environmentally friendly, multi-purpose cationic polymer. The guanidine group in the polyhexamethylene guanidine hydrochloride molecule has high reactivity, making the polymer molecule positively charged. The cell membranes of most bacteria and viruses are negatively charged. Based on the electrostatic attraction between the positive and negative charges, polyhexamethylene guanidine hydrochloride molecules are easily adsorbed by bacteria and viruses.

[0016] Once adsorbed, polyhexamethylene guanidine hydrochloride molecules inhibit the division function of bacteria and viruses, rendering them incapable of reproduction. Simultaneously, as a high-molecular-weight polymer, polyhexamethylene guanidine hydrochloride can form a thin film on the surface of microorganisms, blocking their respiratory channels and causing them to rapidly suffocate and die.

[0017] Polyether ester amide is a nonionic polymeric antistatic agent, while polyhexamethylene guanidine hydrochloride is a cationic polymeric antibacterial agent. Both exhibit good chemical compatibility and will not undergo precipitation or deactivation reactions. As both are polymeric additives, they function independently within the PBT matrix, achieving a synergistic effect of "one agent for antistatic, one agent for antibacterial."

[0018] This application significantly improves the fineness and softness of the fibers by adding ultra-fine seaweed powder to the formula, eliminating the rough and frictional feeling of ordinary filling brush bristles; at the same time, it enhances the powder adsorption and locking ability of makeup powder, reducing fallout and making makeup more even and adherent; the addition of polyether ester amide and polyhexamethylene guanidine hydrochloride to the formula allows them to exert antistatic and antibacterial functions independently in the PBT matrix, achieving a synergistic effect of "one agent for antistatic and one agent for antibacterial".

[0019] Preferably, the ultrafine seaweed powder modified PBT cosmetic brush bristles also contain 10-15 parts of GMA grafted elastomer.

[0020] By employing the above technical solution, the GMA-grafted elastomer molecular chain contains reactive epoxy groups. During melt blending, these epoxy groups can chemically react with the carboxyl and hydroxyl groups at the ends of the PBT molecular chain to form covalent bonds. This chemical reaction establishes a strong interfacial chemical bond between the PBT matrix and the elastomer dispersion phase, significantly improving their compatibility.

[0021] Due to the excellent interfacial bonding between GMA-grafted elastomer and PBT, the elastomer particles can be uniformly dispersed in the PBT matrix at a relatively small size. When the brush bristles are subjected to bending deformation under external force, the uniformly dispersed elastomer particles can effectively absorb and dissipate impact energy. Specifically, under the action of external force, debonding and internal cavitation occur at the interface between the elastomer particles and the PBT matrix, generating micropores; subsequently, the PBT matrix surrounding these micropores undergoes shear yielding, further absorbing energy. This multi-stage energy dissipation mechanism significantly improves the material's impact toughness and resilience.

[0022] The addition of GMA-grafted elastomer establishes a strong interfacial bond between PBT and the elastomer through a chemical reaction, enabling the elastomer particles to effectively absorb and dissipate energy during bending deformation. This significantly improves the resilience and bending fatigue resistance of the bristles without drastically sacrificing rigidity, effectively compensating for the elasticity reduction caused by polyether ester amide.

[0023] Preferably, the propyltriethoxysilane isocyanate is present in 1.0-1.2 parts by weight.

[0024] By employing the above technical solutions, GMA-grafted elastomers are highly efficient toughening agents. Their epoxy groups can react with the terminal groups of PBT, significantly improving interfacial compatibility and impact toughness. However, this toughening often comes at the cost of some strength and rigidity. One method to improve the rigidity of PBT is to use chain extenders. Chain extenders are substances that can react with the terminal groups (hydroxyl and carboxyl groups) of PBT molecular chains, connecting short molecular chains to lengthen the chains, increase molecular weight, and thus enhance the material's cohesion and rigidity. Propyltriethoxysilane isocyanate in the formulation, besides acting as a coupling agent, is itself a highly efficient chain extender. Its core lies in the high reactivity of the isocyanate groups in the molecule, which can rapidly react with the hydroxyl and carboxyl groups at the ends of PBT molecular chains, connecting multiple PBT molecular chains to achieve chain extension and increased adhesion. Therefore, in order to maintain or improve the rigidity of PBT after the introduction of elastomer, it is necessary to increase the amount of propyltriethoxysilane isocyanate to enhance its chain extension effect, thereby achieving the ultimate goal of "rigidity-toughness balance".

[0025] Preferably, the method for preparing the GMA-grafted elastomer includes the following steps: Premix: Mix 100 parts of polyolefin elastomer, 3-8 parts of glycidyl methacrylate, 3-8 parts of styrene, and 0.3-1 parts of dicumyl peroxide to obtain a premix; Grafting: The premixed material is subjected to a melt grafting reaction at 140-200℃ and then extruded. After cooling and pelletizing, GMA grafted elastomer is obtained.

[0026] Preferably, the ultrafine seaweed powder modified PBT cosmetic brush bristles also contain 0.2-0.5 parts of sodium benzoate.

[0027] By employing the above technical solution, PBT, a semi-crystalline polymer, exhibits a relatively low heat distortion temperature primarily due to its relatively low crystallinity. Sodium benzoate, acting as a nucleating agent, provides a large number of heterogeneous crystal nuclei during the melting and cooling process of PBT, enabling the PBT molecular chains to rapidly align and crystallize around these nuclei. The nucleating agent increases the number of crystal nuclei per unit volume, resulting in finer and more uniform spherulites. This fine grain structure facilitates the uniform distribution and transmission of stress within the material.

[0028] GMA-grafted elastomers toughen PBT through interfacial reactions, primarily improving the material's impact toughness and resilience. However, this toughening often comes at the cost of some strength and stiffness. Sodium benzoate, on the other hand, strengthens the material from another dimension—by increasing the crystallinity and stiffness of the matrix itself. Since their mechanisms of action are different and do not interfere with each other, they achieve a synergistic strengthening effect of "elastomer toughening + nucleating agent stiffening."

[0029] The addition of sodium benzoate significantly improves the rigidity and dimensional stability of the bristles by providing numerous crystal nuclei, increasing crystallinity, and refining grains within the PBT matrix. Simultaneously, since the GMA-grafted elastomer has already addressed the toughness (resilience) issue, the rigidity enhancement from sodium benzoate and the toughness enhancement from GMA-grafted elastomer achieve a balance between rigidity and toughness. This allows the bristles to possess both excellent resilience and sufficient stiffness, meeting the dual requirements of "soft yet powerful" in cosmetic brush bristles.

[0030] Secondly, this application provides a method for preparing ultrafine seaweed powder modified PBT cosmetic brush bristles, using the following technical solution: A method for preparing ultrafine seaweed powder modified PBT cosmetic brush bristles, comprising the following steps: Premix: Mix the prescribed amounts of PBT, seaweed powder, propyltriethoxysilane isocyanate, calcium stearate, polyether ester amide, polyhexamethylene guanidine hydrochloride, titanium dioxide, GMA grafted elastomer, and sodium benzoate to obtain a mixture. Granulation: The mixture is melted and extruded at 230-260℃, cooled and pelletized to obtain modified PBT composite material particles; Melt spinning: Modified PBT composite material particles are melt-spun at 270-290℃, cooled, oiled, stretched, and heat-set before being wound into shape to obtain ultrafine seaweed powder modified PBT cosmetic brush filaments.

[0031] Preferably, in the premixing step, 15-20 wt% of the formulated amount of PBT and the formulated amount of polyhexamethylene guanidine hydrochloride are pre-prepared into an antibacterial masterbatch; The method for preparing the antibacterial masterbatch includes the following steps: Mix 15-20 wt% of PBT and 1 wt% of polyhexamethylene guanidine hydrochloride, then melt-extrude at 230-250°C, cool and granulate to obtain antibacterial masterbatch.

[0032] By employing the above technical solution, due to the poor compatibility between polyhexamethylene guanidine hydrochloride and PBT, the polyhexamethylene guanidine hydrochloride particles tend to agglomerate during direct blending, making it difficult to achieve uniform dispersion in the PBT matrix. Uneven dispersion can easily lead to significant differences in antibacterial properties in different regions of the brush filaments. Some regions may have excessively low antibacterial agent content, resulting in a loss of antibacterial effect, while other regions may have antibacterial agent agglomeration forming defect points, affecting spinning stability and brush filament mechanical properties.

[0033] This invention effectively solves the aforementioned problems by first preparing an antibacterial masterbatch from a portion of PBT and polyhexamethylene guanidine hydrochloride. During the masterbatch preparation process, polyhexamethylene guanidine hydrochloride in the PBT carrier is forcibly dispersed into tiny particles under the high shear force of a twin-screw extruder. This process is equivalent to pre-dispersing and pre-diluting polyhexamethylene guanidine hydrochloride.

[0034] When an antibacterial masterbatch containing a high concentration of polyhexamethylene guanidine hydrochloride is blended a second time with the remaining PBT and other components, the polyhexamethylene guanidine hydrochloride in the masterbatch is already uniformly dispersed in the carrier at a very small size. Therefore, the second blending only requires melting and mixing the masterbatch carrier with the PBT matrix, significantly reducing the difficulty of dispersion. This ensures a uniform distribution of polyhexamethylene guanidine hydrochloride in the final product, thereby guaranteeing the uniformity and stability of the antibacterial effect.

[0035] Preferably, in the premixing step, the seaweed powder and propyltriethoxysilane of the formulation are first mixed at 100-120°C to obtain pretreated seaweed powder.

[0036] By employing the above technical solution, in the one-step blending system, the -NCO group of propyltriethoxysilane isocyanate reacts not only with the -OH group of seaweed powder, but also with the -OH group at the end of PBT and the -NH- group (the guanidine group contains active hydrogen) in polyhexamethylene guanidine hydrochloride. This multidirectional competitive reaction consumes a large amount of coupling agent, resulting in insufficient coupling agent actually used for coating the surface of seaweed powder.

[0037] This invention involves pre-treating seaweed powder and propyltriethoxysilane separately at 100-120°C. During this pre-treatment stage, only seaweed powder and propyltriethoxysilane exist in the system; competing reactants such as PBT and polyhexamethylene guanidine hydrochloride are absent. Therefore, the -NCO groups of propyltriethoxysilane preferentially and efficiently react with the hydroxyl groups on the surface of the seaweed powder, forming a strong chemical anchor. This is equivalent to "dressing" each seaweed powder particle with a layer of organic coupling agent molecules.

[0038] The pretreated seaweed powder-coupling agent composite particles exhibit good chemical similarity and physical entanglement with the PBT matrix due to the organic layer (organic segments from the coupling agent) on their surface. When the pretreated seaweed powder is subsequently blended with PBT, the organic segments of the coupling agent can anchor themselves into the PBT molecular chain network, establishing a dual connection of chemical bonding and physical entanglement between PBT and seaweed powder, significantly improving their interfacial compatibility.

[0039] The improved interface bonding means that the seaweed powder particles are more evenly dispersed in the PBT matrix with fewer interface defects, ensuring the tensile strength, resilience and other mechanical properties of the bristles. At the same time, the seaweed powder is evenly distributed on the fiber surface in the form of individual particles (rather than agglomerates), achieving the micron-level uneven structure expected in the design, avoiding large particle protrusions and skin-pricking sensation caused by agglomeration.

[0040] In summary, this application has the following beneficial effects: This application significantly improves the fineness and softness of the fibers by adding ultra-fine seaweed powder to the formula, eliminating the rough and frictional feeling of ordinary filling brush bristles; at the same time, it enhances the powder adsorption and locking ability of makeup powder, reducing fallout and making makeup more even and adherent; the addition of polyether ester amide and polyhexamethylene guanidine hydrochloride to the formula allows them to exert antistatic and antibacterial functions independently in the PBT matrix, achieving a synergistic effect of "one agent for antistatic and one agent for antibacterial". Detailed Implementation

[0041] Example 1

[0042] A method for preparing ultrafine seaweed powder modified PBT cosmetic brush bristles includes the following steps: Premixing: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, and 0.8g titanium dioxide to obtain a mixture; the seaweed powder has a particle size of 4-5μm; Granulation: The mixture is melted and extruded at 230-260℃, cooled and pelletized to obtain modified PBT composite material particles; Melt spinning: Modified PBT composite material particles are melt-spun at 270-290℃, cooled, oiled, stretched, and heat-set before being wound into shape to obtain ultrafine seaweed powder modified PBT cosmetic brush filaments.

[0043] Example 2-3

[0044] Examples 2-3 are based on the preparation method of Example 1, but the content of raw materials for preparing ultrafine seaweed powder modified PBT cosmetic brush bristles is adjusted. The specific adjustments are shown in Table 1.

[0045] Comparative Examples 1-3 Comparative Example 1 was prepared using the same method as in Example 1, but without the addition of seaweed powder.

[0046] Comparative Example 2 was prepared by replacing 100g of polyether ester amide with 100g of antistatic agent SN, based on the preparation method of Example 1.

[0047] Comparative Example 3 was prepared by replacing 100g of polyether ester amide with 100g of ethoxylated alkylamine, based on the preparation method of Example 1.

[0048] Performance testing The ultrafine seaweed powder modified PBT cosmetic brush bristles of Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests, and the test results are shown in Table 1.

[0049] Tactile rating Makeup brushes were made by modifying PBT bristles with ultrafine seaweed powder, and 10 female volunteers were selected to experience and evaluate them. The evaluation level was from best to worst: velvety feel, slightly itchy, moderately itchy, and severely itchy. The final rating was based on the consistent results of at least 8 volunteers out of the 10 volunteers.

[0050] Powder volume Makeup brushes are made by modifying PBT bristles with ultra-fine seaweed powder. Before use, each makeup brush is gently wiped with a clean cotton pad to remove any loose hairs and impurities, ensuring a consistent initial condition.

[0051] The initial mass of the matte loose powder was weighed using an electronic balance and recorded as M1. The inspector, wearing disposable gloves, held a makeup brush and rotated it three times in the powder with the same force and method, simulating the everyday action of picking up powder.

[0052] After picking up the powder, gently shake off the excess loose powder with the makeup brush, then weigh the remaining matte powder using an electronic balance and record it as M2.

[0053] Calculate the powder pickup amount for each makeup brush, where powder pickup amount = M1 - M2. To ensure data accuracy, each makeup brush was tested three times for each type of loose powder, and the average value was taken as the final powder pickup amount.

[0054] Antistatic Makeup brushes were made by modifying PBT bristles with ultrafine seaweed powder. The surface resistivity of the makeup brushes was measured according to ANSI / ESD STM11.11.

[0055] Antibacterial rate The antibacterial rate of ultrafine seaweed powder modified PBT cosmetic brush bristles was tested according to GB / T 31402-2023.

[0056] toughness The PBT makeup brush filaments modified with ultrafine seaweed powder were bent at 90° and held for 24 hg before being released. The angle A at which the filaments recovered was measured, and the resilience rate was calculated as (A / 180°) × 100%.

[0057] rigidity The flexural modulus of ultrafine seaweed powder modified PBT cosmetic brush bristles was determined according to GB / T 1040-2025.

[0058] Table 1. Performance Test Results of Ultrafine Seaweed Powder Modified PBT Makeup Brush Bristles in Examples 1-3 and Comparative Examples 1-3 (Unit: g)

[0059] Referring to Table 1, comparing Examples 1-3 and Comparative Examples 1-3, it can be seen that the ultrafine seaweed powder modified PBT cosmetic brush filaments obtained by the above preparation method have better effects. The reason is that this invention uses 3000-mesh ultrafine seaweed powder (particle size 4-5 μm) as the modified filler, which has a very large specific surface area. During melt spinning, the seaweed powder particles are uniformly dispersed inside the PBT matrix and partially exposed on the fiber surface, constructing a fine and uniform micron-level uneven structure on the fiber surface. Its surface contains abundant hydrophilic groups such as hydroxyl (-OH), possessing a certain degree of natural lubricity. At the interface between the seaweed powder and PBT, due to the bridging effect of the coupling agent, the seaweed powder particles are coated with organic long chains, transforming the feel from a rough "hard granular feel" to a lubricating "velvety feel." Meanwhile, the micron-level concave-convex structure creates a micro-texture similar to natural animal hair in terms of touch, which greatly improves the smoothness and softness of the fiber when it comes into contact with the skin, eliminates the rough friction of ordinary filling brush bristles, and achieves a high-end skin-friendly effect with zero skin irritation.

[0060] The micron-level uneven structure on the fiber surface significantly increases the contact area and physical adhesion between the brush bristles and the makeup powder. When the brush bristles come into contact with the makeup powder, the powder particles are captured in the "micro-pits" of the uneven structure, thereby enhancing the powder adsorption and retention capacity. At the same time, seaweed powder itself has certain oil-absorbing and moisturizing properties, which can absorb the oil components in the makeup, further enhancing the adhesion stability of the powder. This structural design makes the powder less likely to fall during makeup application (reducing fallout), and the powder is released evenly and adheres well to the skin surface, reducing the need for multiple powder pick-ups. Furthermore, since the uneven structure formed by the seaweed powder on the fiber surface is not obtained through destructive means such as chemical corrosion, the fiber structure itself remains intact, so the resilience and water resistance of the brush bristles are not affected.

[0061] Polyether ester amide is a nonionic polymeric antistatic agent, while polyhexamethylene guanidine hydrochloride is a cationic polymeric antibacterial agent. Both exhibit good chemical compatibility and will not undergo precipitation or deactivation reactions. As both are polymeric additives, they function independently within the PBT matrix, achieving a synergistic effect of "one agent for antistatic, one agent for antibacterial."

[0062] Examples 4-6

[0063] Example 4 is based on the preparation method of Example 1, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 100g GMA grafted elastomer to obtain a mixture.

[0064] The method for preparing GMA-grafted elastomers includes the following steps: Premix: Mix 1000g of polyolefin elastomer, 50g of glycidyl methacrylate (30-80g is acceptable), 50g of styrene (30-80g is acceptable), and 7g of dicumyl peroxide (3-10g is acceptable) to obtain a premix; Grafting: The premixed material is subjected to a melt grafting reaction at 140-200℃ and then extruded. After cooling and pelletizing, GMA grafted elastomer is obtained.

[0065] Example 5 is based on the preparation method of Example 4, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 125g GMA grafted elastomer to obtain a mixture.

[0066] Example 6 is based on the preparation method of Example 4, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 150g GMA grafted elastomer to obtain a mixture.

[0067] Comparative Example 4-5 Comparative Example 4 adjusts the preparation method based on the preparation method of Example 4 as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 80g GMA grafted elastomer to obtain a mixture.

[0068] Comparative Example 5, based on the preparation method of Example 4, adjusts the preparation method as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 170g GMA grafted elastomer to obtain a mixture.

[0069] The ultrafine seaweed powder modified PBT cosmetic brush bristles of Examples 1, 4-6 and Comparative Examples 4-5 were subjected to the above performance tests, and the test results are shown in Table 2.

[0070] Table 2 Performance test results for Examples 1, 4-6 and Comparative Examples 4-5

[0071] Referring to Table 2, a comparison of Examples 1, 4-6, and 4-5 shows that adding GMA-grafted elastomer to the formulation results in ultrafine seaweed powder-modified PBT cosmetic brush bristles with better performance. This is because the GMA-grafted elastomer molecular chain contains reactive epoxy groups. During melt blending, these epoxy groups can chemically react with the carboxyl and hydroxyl groups at the ends of the PBT molecular chain to form covalent bonds. This chemical reaction establishes a strong interfacial chemical bond between the PBT matrix and the elastomer dispersion phase, significantly improving their compatibility.

[0072] Due to the excellent interfacial bonding between GMA-grafted elastomer and PBT, the elastomer particles can be uniformly dispersed in the PBT matrix at a relatively small size. When the brush bristles are subjected to bending deformation under external force, the uniformly dispersed elastomer particles can effectively absorb and dissipate impact energy. Specifically, under the action of external force, debonding and internal cavitation occur at the interface between the elastomer particles and the PBT matrix, generating micropores; subsequently, the PBT matrix surrounding these micropores undergoes shear yielding, further absorbing energy. This multi-stage energy dissipation mechanism significantly improves the material's impact toughness and resilience.

[0073] The addition of GMA-grafted elastomer establishes a strong interfacial bond between PBT and the elastomer through a chemical reaction, enabling the elastomer particles to effectively absorb and dissipate energy during bending deformation. This significantly improves the resilience and bending fatigue resistance of the bristles without drastically sacrificing rigidity, effectively compensating for the elasticity reduction caused by polyether ester amide.

[0074] Examples 7-11

[0075] Example 7 is based on the preparation method of Example 1, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 6g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, and 0.8g titanium dioxide to obtain a mixture.

[0076] Example 8 is based on the preparation method of Example 1, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 10g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, and 0.8g titanium dioxide to obtain a mixture.

[0077] Example 9 is based on the preparation method of Example 5, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 10g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 125g GMA grafted elastomer to obtain a mixture.

[0078] Example 10 is based on the preparation method of Example 5, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 11g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 125g GMA grafted elastomer to obtain a mixture.

[0079] Example 11 is based on the preparation method of Example 5, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 12g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, and 125g GMA grafted elastomer to obtain a mixture.

[0080] The ultrafine seaweed powder modified PBT cosmetic brush bristles of Examples 7-11 were subjected to the above performance tests, and the test results are shown in Table 3.

[0081] Table 3 Performance test results for Examples 1, 5 and 7-11

[0082] Referring to Table 3, comparing Examples 1, 5, and 7-11, it can be seen that the formulation without GMA-grafted elastomer, with an addition of 6-10 parts of propyltriethoxysilane, yields better ultrafine seaweed powder-modified PBT cosmetic brush filaments. The formulation with GMA-grafted elastomer, with an addition of 10-12 parts of propyltriethoxysilane, also yields better ultrafine seaweed powder-modified PBT cosmetic brush filaments. This is because GMA-grafted elastomer is a highly efficient toughening agent. Its epoxy groups can react with the terminal groups of PBT, significantly improving interfacial compatibility and impact toughness. However, this toughening often comes at the cost of some strength and rigidity. One method to improve the rigidity of PBT is to use chain extenders. Chain extenders are substances that can react with the terminal groups (hydroxyl and carboxyl groups) of PBT molecular chains, connecting short molecular chains, extending the molecular chains, increasing the molecular weight, and thus enhancing the cohesion and rigidity of the material. The isopropyltriethoxysilane in the formulation, besides acting as a coupling agent, is also a highly efficient chain extender. Its core strength lies in the high reactivity of the isocyanate groups in the molecule, which can rapidly react with the hydroxyl and carboxyl groups at the ends of the PBT molecular chains, linking multiple PBT molecular chains together to achieve chain extension and increased viscosity. Therefore, in order to maintain or improve the rigidity of PBT after its introduction into the elastomer, it is necessary to increase the amount of isopropyltriethoxysilane to enhance its chain-extending effect, thereby achieving the ultimate goal of "rigidity-toughness balance".

[0083] Examples 12-14

[0084] Example 12 is based on the preparation method of Example 5, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, 125g GMA grafted elastomer, and 2g sodium benzoate to obtain a mixture.

[0085] Example 13 is based on the preparation method of Example 5, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, 125g GMA grafted elastomer, and 4g sodium benzoate to obtain a mixture.

[0086] Example 14 is based on the preparation method of Example 5, but the preparation method is adjusted as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 5g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, 125g GMA grafted elastomer, and 5g sodium benzoate to obtain a mixture.

[0087] Comparative Example 6, based on the preparation method of Example 5, adjusts the preparation method as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, 125g GMA grafted elastomer, and 1g sodium benzoate to obtain a mixture.

[0088] Comparative Example 7, based on the preparation method of Example 5, adjusted the preparation method as follows: Premix: Mix 970g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, 0.8g titanium dioxide, 125g GMA grafted elastomer, and 7g sodium benzoate to obtain a mixture.

[0089] The ultrafine seaweed powder modified PBT cosmetic brush bristles of Examples 12-14 and Comparative Examples 6-7 were subjected to the above performance tests, and the test results are shown in Table 4.

[0090] Table 4 Performance test results for Examples 5, 12-14 and Comparative Examples 6-7

[0091] Referring to Table 4, comparing Examples 5, 12-14, and 6-7, it is evident that adding 0.2-0.5 parts of sodium benzoate to the formulation, in addition to the GMA-grafted elastomer, further enhances the effect of the ultrafine seaweed powder-modified PBT cosmetic brush bristles. This is because PBT is a semi-crystalline polymer, and its relatively low heat distortion temperature is fundamentally due to its relatively low crystallinity. Sodium benzoate, acting as a nucleating agent, provides a large number of heterogeneous crystal nuclei during the melting and cooling process of PBT, enabling the PBT molecular chains to rapidly align and crystallize around these nuclei. The nucleating agent increases the number of nuclei per unit volume, resulting in finer and more uniform spherulites. This fine grain structure facilitates the uniform distribution and transmission of stress within the material.

[0092] GMA-grafted elastomers toughen PBT through interfacial reactions, primarily improving the material's impact toughness and resilience. However, this toughening often comes at the cost of some strength and stiffness. Sodium benzoate, on the other hand, strengthens the material from another dimension—by increasing the crystallinity and stiffness of the matrix itself. Since their mechanisms of action are different and do not interfere with each other, they achieve a synergistic strengthening effect of "elastomer toughening + nucleating agent stiffening."

[0093] The addition of sodium benzoate significantly improves the rigidity and dimensional stability of the bristles by providing numerous crystal nuclei, increasing crystallinity, and refining grains within the PBT matrix. Simultaneously, since the GMA-grafted elastomer has already addressed the toughness (resilience) issue, the rigidity enhancement from sodium benzoate and the toughness enhancement from GMA-grafted elastomer achieve a balance between rigidity and toughness. This allows the bristles to possess both excellent resilience and sufficient stiffness, meeting the dual requirements of "soft yet powerful" in cosmetic brush bristles.

[0094] Examples 15-18

[0095] Example 15 is based on the preparation method of Example 1, but the preparation method is adjusted as follows: Premix: Mix 776g PBT, 30g seaweed powder, 8g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 197g antibacterial masterbatch, and 0.8g titanium dioxide to obtain a mixture.

[0096] The preparation method of antibacterial masterbatch includes the following steps: 194g of PBT and 3g of polyhexamethylene guanidine hydrochloride were mixed, then melt-extruded at 230-250℃, and granulated after cooling to obtain 197g of antibacterial masterbatch.

[0097] The amount of PBT added to the antibacterial masterbatch can be 145.5g-194g. When the amount of PBT added to the antibacterial masterbatch decreases, the amount of PBT added during premixing should be increased to ensure that the amount of PBT added in the mixture is 970g.

[0098] Example 16 is based on the preparation method of Example 1, but the preparation method is adjusted as follows: Premixing: Mix 970g PBT, 38g pretreated seaweed powder, 5g calcium stearate, 100g polyether ester amide, 3g polyhexamethylene guanidine hydrochloride, and 0.8g titanium dioxide to obtain a mixture.

[0099] The method for preparing pretreated seaweed powder includes the following steps: 30g of seaweed powder and 8g of propyltriethoxysilane isocyanate were mixed at 100-120℃ to obtain pretreated seaweed powder.

[0100] Example 17 is based on the preparation method of Example 15, but the preparation method is adjusted as follows: Premixing: Mix 776g PBT, 38g pretreated seaweed powder, 3g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 197g antibacterial masterbatch, 0.8g titanium dioxide, and 125g GMA grafted elastomer to obtain a mixture.

[0101] The method for preparing pretreated seaweed powder includes the following steps: 30g of seaweed powder and 8g of propyltriethoxysilane isocyanate were mixed at 100-120℃ to obtain pretreated seaweed powder.

[0102] Example 18 is based on the preparation method of Example 15, but the preparation method is adjusted as follows: Premixing: Mix 776g PBT, 38g pretreated seaweed powder, 3g propyltriethoxysilane isocyanate, 5g calcium stearate, 100g polyether ester amide, 197g antibacterial masterbatch, 0.8g titanium dioxide, 125g GMA grafted elastomer, and 4g sodium benzoate to obtain a mixture.

[0103] The method for preparing pretreated seaweed powder includes the following steps: 30g of seaweed powder and 8g of propyltriethoxysilane isocyanate were mixed at 100-120℃ to obtain pretreated seaweed powder.

[0104] The ultrafine seaweed powder modified PBT cosmetic brush bristles of Examples 15-18 were subjected to the above performance tests, and the test results are shown in Table 5.

[0105] Table 5 Performance test results for Examples 1 and 15-18

[0106] Referring to Table 5, comparing Example 1 and Examples 15-18, it can be seen that preparing antibacterial masterbatch by partially using PBT and polyhexamethylene guanidine hydrochloride, or preparing pretreated seaweed powder and propyltriethoxysilane isocyanate, results in ultrafine seaweed powder modified PBT cosmetic brush bristles having a stronger effect.

[0107] In addition, when antibacterial masterbatch and pretreated seaweed powder are used in the formula, the addition of GMA grafted elastomer and sodium benzoate further improves the effect of ultrafine seaweed powder modified PBT cosmetic brush bristles.

[0108] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A type of ultrafine seaweed powder modified PBT cosmetic brush bristles, characterized in that, Includes the following components in parts by weight: The composition includes 95-100 parts PBT, 2-4 parts seaweed powder, 0.6-1.2 parts propyltriethoxysilane isocyanate, 0.4-0.6 parts calcium stearate, 5-15 parts polyether ester amide, 0.2-0.4 parts polyhexamethylene guanidine hydrochloride, and 0.05-0.1 parts titanium dioxide; the seaweed powder has a particle size of 4-5 μm.

2. The ultrafine seaweed powder modified PBT cosmetic brush bristles according to claim 1, characterized in that: Also added 10-15 parts of GMA-grafted elastomer.

3. The ultrafine seaweed powder modified PBT cosmetic brush bristles according to claim 2, characterized in that: The propyltriethoxysilane isocyanate is present in parts by weight of 1.0-1.

2.

4. The ultrafine seaweed powder modified PBT cosmetic brush bristles according to claim 2, characterized in that: The method for preparing the GMA-grafted elastomer includes the following steps: Premix: Mix 100 parts of polyolefin elastomer, 3-8 parts of glycidyl methacrylate, 3-8 parts of styrene, and 0.3-1 parts of dicumyl peroxide to obtain a premix; Grafting: The premixed material is subjected to a melt grafting reaction at 140-200℃ and then extruded. After cooling and pelletizing, GMA grafted elastomer is obtained.

5. The ultrafine seaweed powder modified PBT cosmetic brush bristles according to claim 2, characterized in that: Also add 0.2-0.5 parts of sodium benzoate.

6. The method for preparing ultrafine seaweed powder modified PBT cosmetic brush bristles according to any one of claims 1-5, characterized in that, Includes the following steps: Premix: Mix the prescribed amounts of PBT, seaweed powder, propyltriethoxysilane isocyanate, calcium stearate, polyether ester amide, polyhexamethylene guanidine hydrochloride, titanium dioxide, GMA grafted elastomer, and sodium benzoate to obtain a mixture. Granulation: The mixture is melted and extruded at 230-260℃, cooled and pelletized to obtain modified PBT composite material particles; Melt spinning: Modified PBT composite material particles are melt-spun at 270-290℃, cooled, oiled, stretched, and heat-set before being wound into shape to obtain ultrafine seaweed powder modified PBT cosmetic brush filaments.

7. The method for preparing ultrafine seaweed powder modified PBT cosmetic brush bristles according to claim 6, characterized in that: In the premixing step, 15-20 wt% of the formulated amount of PBT and the formulated amount of polyhexamethylene guanidine hydrochloride are pre-prepared into antibacterial masterbatch; The method for preparing the antibacterial masterbatch includes the following steps: Mix 15-20 wt% of PBT and 1 wt% of polyhexamethylene guanidine hydrochloride, then melt-extrude at 230-250°C, cool and granulate to obtain antibacterial masterbatch.

8. The ultrafine seaweed powder modified PBT cosmetic brush bristles according to claim 6, characterized in that: In the premixing step, the seaweed powder and propyltriethoxysilane of the formulation are mixed at 100-120°C to obtain pretreated seaweed powder.

Images