A low-sensitization PC / ABS composite master batch and a preparation method thereof

Abstract

The application relates to the technical field of high polymer modified composite materials, in particular to a low-sensitization PC / ABS composite master batch and a preparation method thereof, which comprises the following components: PC resin, ABS resin, anti-allergy functional units, polyurethane elastomer, sodium hyaluronate, antibacterial powder, a surface modifier and auxiliary processing aids. The application captures residual sensitizing small molecules in the matrix, optimizes the two-phase interface through the anti-allergy units, and constructs a micro-nano hydrophobic protective structure on the surface layer of the material through the surface modifier. The skin sensitization rate of the composite material is less than or equal to 0.25%, the surface water contact angle is greater than or equal to 115 DEG, the antibacterial rate is greater than or equal to 98.7%, the mechanical properties are excellent, and the composite material is suitable for plastic products such as children's plastic accessories, medical and beauty contact instruments, wearable electronic shells and close-fitting household products.

Description

Technical Field

[0001] This invention relates to the field of polymer modified composite materials technology, specifically to a low-allergenic PC / ABS composite masterbatch and its preparation method. Background Technology

[0002] PC / ABS composite masterbatch, an alloy plastic of polycarbonate (PC) and acrylonitrile-butadiene-styrene copolymer (ABS), has experienced rapid growth in the global and Chinese markets in recent years due to its excellent comprehensive properties. This material retains the high strength, heat resistance, and dimensional stability of PC while incorporating the good processability, toughness, and surface decoration characteristics of ABS. Advanced blending modification technology achieves synergistic performance enhancement. With the increasing demands for material performance from downstream applications, PC / ABS composite masterbatch is developing towards high performance, functional integration, and environmental sustainability, becoming one of the preferred engineering plastics in many industries.

[0003] In terms of applications, PC / ABS composite masterbatch demonstrates broad applicability. The electronics and home appliance industry is its largest application market, primarily used to manufacture the casings and internal structural components of smartphones, tablets, and laptops, as well as components for home appliances such as washing machine housings, refrigerator liners, and air conditioner panels. These applications fully utilize the excellent mechanical properties, heat resistance, and surface gloss of PC / ABS, meeting the dual requirements of lightweighting and structural strength in electronic products, while also providing rich design possibilities for home appliances. In smart wearable devices, the application of PC / ABS composite masterbatch is also becoming increasingly widespread. Products such as smartwatch straps and VR headset pads are beginning to use PC / ABS materials extensively to balance comfort and functionality.

[0004] Despite the significant application potential of PC / ABS composite masterbatch in wearable devices, its application in this field still faces numerous challenges. Firstly, there are biocompatibility issues; some low-molecular-weight additives or incompletely polymerized monomers (such as bisphenol A) may leach out during use, triggering skin allergies and causing symptoms such as contact dermatitis. Secondly, there are shortcomings in comfort; the material's high surface roughness and microporous structure easily attract dust and sweat, fostering bacterial growth and exhibiting poor stain resistance. Summary of the Invention

[0005] To address the shortcomings of existing skin-contact PC / ABS materials, such as the potential for small molecule residues to cause allergies, easy adsorption of contaminants on the surface, easy bacterial growth, and poor component compatibility, this invention provides a low-allergenic PC / ABS composite masterbatch that can be used in wearable devices and its preparation method.

[0006] This invention provides a hypoallergenic PC / ABS composite masterbatch, comprising the following components by weight: PC resin: 50-70 parts; ABS resin: 20-40 parts; anti-allergy functional unit: 3-8 parts; polyurethane elastomer: 1-5 parts; sodium hyaluronate: 0.5-2 parts; antibacterial powder: 0.1-1 parts; surface modifier: 0.05-0.3 parts; auxiliary processing aids: 1.2-3.5 parts, wherein the auxiliary processing aids include antioxidants, compatibilizers, and internal lubricants.

[0007] Furthermore, the anti-allergy functional unit is prepared by compounding maleic anhydride-grafted ABS and β-glucan cross-linked microspheres at a mass ratio of 2:1.

[0008] Furthermore, the preparation method of the anti-allergy functional unit includes the following steps: Preparation of MAH-g-ABS: ABS resin, maleic anhydride, and initiator BPO are mixed in a mass ratio of 100:6-8:1-1.2. The mixture is then stirred in an internal mixer at a constant temperature of 185-190℃ and a speed of 50-60 r / min for 25-30 min. The mixture is then extruded and granulated to obtain maleic anhydride-grafted ABS with a grafting rate of 3.2% to 3.8%. Preparation of β-glucan cross-linked microspheres: β-glucan was dissolved in deionized water to prepare a 4% homogeneous solution, glutaraldehyde cross-linking agent was added, and the solution was magnetically stirred at room temperature for 2-2.5 h. Microspheres were prepared by spray drying, and microspheres with a particle size of 500-800 nm were screened for later use. Compound modification: MAH-g-ABS and β-glucan microspheres are mixed at a mass ratio of 2-2.5:1, stirred at high speed for 15-20 minutes, and passed through a 300-mesh sieve to obtain the anti-allergy functional unit.

[0009] Furthermore, the preparation method of the surface modifier includes the following steps: Perfluorooctyltriethoxysilane was diluted with anhydrous ethanol at a mass ratio of 1:4 and ultrasonically dispersed for 10 min to obtain a homogeneous silane solution. Then, dendritic polyglycerol ester was added, and the mass ratio of perfluorooctyltriethoxysilane to dendritic polyglycerol ester was strictly controlled at 1:1.2-1.5. The mixture was stirred at a constant temperature of 45℃ for 1.2-1.5 h for compound modification. Finally, the ethanol solvent was removed by vacuum distillation to obtain the viscous surface modifier.

[0010] Furthermore, the antibacterial powder is selected from nano zinc oxide antibacterial powder, wherein the particle size of the nano zinc oxide antibacterial powder is 30-50 nm.

[0011] Furthermore, the auxiliary processing aids comprise, by weight: 0.4 to 1.0 parts of antioxidant 1010, 0.5 to 1.5 parts of styrene-maleic anhydride compatibilizer, and 0.3 to 1.0 parts of glyceryl stearate lubricant.

[0012] This invention also provides a method for preparing a low-allergenic PC / ABS composite masterbatch, comprising the following preparation steps: Step S1: Add ABS resin to the cyclodextrin inclusion complex carrier, stir at a constant temperature of 70-75℃ for 40-50 minutes to complete the activation and inclusion, and pass through a 300-mesh sieve for later use; place PC resin in a forced-air drying oven and dry at 105℃ for 4-5 hours until the moisture content is ≤0.02%, and pass through a 300-mesh sieve for later use. Step S2: The ABS pretreated in Step 1 is fed into a twin-screw extruder, heated and melted, and then molten PC resin is added for shear emulsification. During the process, the screw speed is controlled at 320-350 r / min and the shear pressure is 2.5 MPa. Step S3: Pass the anti-allergy functional unit, antibacterial powder, sodium hyaluronate, and polyurethane elastomer through a 200-mesh sieve to remove agglomerated particles; simultaneously add the anti-allergy functional unit, antibacterial powder, sodium hyaluronate, and polyurethane elastomer to the first heating zone of the twin-screw extruder, and mix them at a uniform speed to ensure that the powder is evenly dispersed. Step S4: Add surface modifier to the metering section at the end of the twin-screw extruder, and control the temperature at 200℃ to form a uniform modified film on the material surface by utilizing the melt flowability. Step S5: Using a three-stage cooling curve: hold at 210℃ for 5 min → hold at 190℃ for 8 min → cool naturally to room temperature, and then extrude and granulate to obtain the low-allergenic PC / ABS composite masterbatch.

[0013] If the masterbatch needs to be injection molded into a product, it needs to be placed in a constant temperature oven for gradient annealing: keep it at 80℃ for 2-3 hours to eliminate internal stress, then cool it down to 60℃ and keep it at 60℃ for 4-4.5 hours to induce interfacial bonding, and then cool it naturally to room temperature to obtain the finished composite material.

[0014] Beneficial effects: 1. This invention achieves internal small molecule capture and interface barrier through anti-allergy functional units, seals the matrix interface gaps by using maleic anhydride grafting structure, and adsorbs sensitizing impurities such as residual styrene monomer and free additives in ABS by using β-glucan porous microspheres; combined with surface modifiers, a dense protective film is formed on the material surface to block external irritants from contacting the substrate, thus doubly inhibiting allergy inducing sources.

[0015] 2. The surface modifier of the present invention can migrate autonomously to the surface during the material molding process to construct a biomimetic lotus leaf micro-nano structure, which significantly improves the hydrophobic and stain-resistant properties of the material.

[0016] 3. The maleic anhydride graft structure in the anti-allergy functional unit optimizes the interfacial bonding between PC and ABS. Combined with the SMA compatibilizer in the formulation, it solves the defects of easy agglomeration, delamination, and interfacial voids in multi-powder blend systems. Compared to pure substrates, the composite material prepared from the masterbatch of this invention exhibits increased tensile strength and simply supported beam impact strength by 6.2 MPa and 3.6 kJ / m², respectively, with stronger material toughness and structural stability, making it suitable for complex operating conditions. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] All raw materials used in the embodiments of this invention can be purchased directly from the market.

[0019] The β-glucan used in this embodiment of the invention is yeast-extracted with a purity of 95%. The glutaraldehyde crosslinking agent used in this embodiment of the invention is a 25% aqueous solution. The dendritic polyglycerol used in this embodiment of the invention has a degree of polymerization of 6 and a hydroxyl value of 520 mg / g. The polyether-type polyurethane elastomer used in this embodiment of the invention has a hardness of 85A and a melting temperature of 175°C.

[0020] The nano zinc oxide antibacterial powder used in the embodiments of the present invention has a particle size of 30-50 nm, a purity of ≥99.5%, is a white powder, and is resistant to high temperatures of ≤260℃. The cyclodextrin inclusion complex carrier used in the embodiments of the present invention is commercially available β-cyclodextrin; The sodium hyaluronate used in this embodiment of the invention has a molecular weight of 1200-1500 kDa, is a white powder, is easily hydrophilic, and is resistant to high temperatures ≤220℃.

[0021] The products mentioned above are preferred embodiments; any similar products that meet the corresponding technical parameters can be substituted.

[0022] Example of preparation of anti-allergy functional unit The preparation method of the anti-allergy functional unit includes the following steps: Preparation of MAH-g-ABS: ABS resin, maleic anhydride, and initiator BPO are mixed in a certain proportion, and the mixture is reacted in an internal mixer at a constant temperature of 185-190℃ and a speed of 50-60r / min for 25-30min. The mixture is then extruded and granulated to obtain maleic anhydride-grafted ABS with a grafting rate of 3.2% to 3.8%. The mass ratio of ABS resin, maleic anhydride, and initiator BPO can be 100:6:1.2, 100:7:1.2, or 100:8:1. In the preparation example of the anti-allergy functional unit, the mass ratio of ABS resin, maleic anhydride, and initiator BPO is 100:6:1.2.

[0023] Preparation of β-glucan cross-linked microspheres: β-glucan was dissolved in deionized water to prepare a 4% homogeneous solution, glutaraldehyde cross-linking agent was added, and the solution was magnetically stirred at room temperature for 2-2.5 h. Microspheres were prepared by spray drying, and microspheres with a particle size of 500-800 nm were screened for later use. Compound modification: MAH-g-ABS and β-glucan microspheres are mixed in a certain mass ratio, stirred at high speed for 15-20 minutes, and passed through a 300-mesh sieve to obtain anti-allergy functional units.

[0024] The mass ratio of MAH-g-ABS to β-glucan microspheres can be 2:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, or 2.5:1. In the preparation example of the anti-allergy functional unit, the mass ratio of MAH-g-ABS to β-glucan microspheres is 2:1.

[0025] Preparation example of surface modifier Example 1 Perfluorooctyltriethoxysilane was diluted with anhydrous ethanol at a mass ratio of 1:4 and ultrasonically dispersed for 10 min to obtain a homogeneous silane solution. Then, dendritic polyglycerol ester was added, and the mass ratio of perfluorooctyltriethoxysilane to dendritic polyglycerol ester was strictly controlled at 1:1.2-1.5. In this preparation example, the mass ratio of perfluorooctyltriethoxysilane to dendritic polyglycerol ester was 1:1.5. Then, the mixture was stirred at a constant temperature of 45℃ for 1.2-1.5 h for compound modification. Finally, the ethanol solvent was removed by vacuum distillation to obtain the viscous surface modifier.

[0026] The anti-allergy functional unit and surface modifier used in the embodiments of the present invention are prepared using the above-described formulation and process.

[0027] The preparation methods for Examples 1-3 are as follows: Step S1: Add ABS resin to the cyclodextrin inclusion complex carrier, stir at a constant temperature of 70-75℃ for 40-50 minutes to complete the activation and inclusion, and pass through a 300-mesh sieve for later use; place PC resin in a forced-air drying oven and dry at 105℃ for 4-5 hours until the moisture content is ≤0.02%, and pass through a 300-mesh sieve for later use. Step S2: The ABS pretreated in Step 1 is fed into a twin-screw extruder, heated and melted, and then molten PC resin is added for shear emulsification. During the process, the screw speed is controlled at 320-350 r / min and the shear pressure is 2.5 MPa. Step S3: Pass the anti-allergy functional unit, antibacterial powder, sodium hyaluronate, and polyurethane elastomer through a 200-mesh sieve to remove agglomerated particles; simultaneously add the anti-allergy functional unit, antibacterial powder, sodium hyaluronate, and polyurethane elastomer to the first heating zone of the twin-screw extruder, and mix them at a uniform speed to ensure that the powder is evenly dispersed. Step S4: Add surface modifier to the metering section at the end of the twin-screw extruder, and control the temperature at 200℃ to form a uniform modified film on the material surface by utilizing the melt flowability. Step S5: Using a three-stage cooling curve: hold at 210℃ for 5 min → hold at 190℃ for 8 min → cool naturally to room temperature, and then extrude and granulate to obtain the low-allergenic PC / ABS composite masterbatch.

[0028] The weight fractions of each component in Examples 1-3 are shown in the table below: Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 did not include an anti-allergy functional unit. The proportions of other components, including the surface modifier and the preparation method, remain unchanged.

[0029] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that no surface modifier was added in Comparative Example 1, the proportions of other components remained unchanged, and the preparation method remained unchanged.

[0030] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that Comparative Example 1 did not add an anti-allergy functional unit, while the proportions of other components and the preparation method remained unchanged.

[0031] Comparative Example 4 In Comparative Example 4, the anti-allergy unit used is different from that in Example 1. The mass ratio of MAH-g-ABS to β-glucan microspheres used in the preparation of the anti-allergy unit in this comparative example is 1:1.

[0032] Comparative Example 5 In Comparative Example 5, the anti-allergy unit used is different from that in Example 1. The mass ratio of MAH-g-ABS to β-glucan microspheres used in the preparation of the anti-allergy unit in this comparative example is 3:1.

[0033] Comparative Example 6 In Comparative Example 6, the anti-allergy unit used is different from that in Example 1. The mass ratio of ABS:maleic anhydride:initiator used in the preparation of the anti-allergy unit in this comparative example is 100:5:1.5.

[0034] Comparative Example 7 In Comparative Example 7, the anti-allergy unit used is different from that in Example 1. The mass ratio of ABS:maleic anhydride:initiator used in the preparation of the anti-allergy unit in this comparative example is 100:10:1.

[0035] Comparative Example 8 In Comparative Example 8, the surface modifier used is different from that in Example 1. The dendritic polyglycerol ester used in the preparation of the surface modifier in this comparative example is replaced with linear polyglycerol ester.

[0036] Comparative Example 9 In Comparative Example 9, the surface modifier used was different from that in Example 1. The mass ratio of perfluorooctyltriethoxysilane to dendritic polyglycerol ester used in the preparation of the surface modifier in this comparative example was 1:2.

[0037] The plastic masterbatches prepared in Examples 1-3 and Comparative Examples 1-9 were injection molded. The operation steps are as follows: the masterbatches were placed in a constant temperature oven for gradient annealing: the internal stress was eliminated by maintaining the temperature at 80℃ for 2-3 hours, then the temperature was lowered to 60℃ and maintained at 60℃ for 4-4.5 hours to induce interfacial bonding, and then naturally cooled to room temperature to obtain the finished composite material.

[0038] Performance testing and corresponding test data 1. This invention combines an allergy-inducing functional unit with a self-made surface modifier. By strictly limiting the proportions of the two types of additives and the preparation process, the internal structure and surface properties of the composite material are optimized. Compared with PC / ABS composite materials, the composite material prepared by the PC / ABS composite masterbatch of this invention has an optimal skin sensitization rate as low as 0.18%, making it suitable for long-term skin contact use by children and people with sensitive skin, with excellent biocompatibility. The pure water contact angle can reach 118.2°, which is 62.8% higher than the 72.6° of Comparative Example 1. It can effectively block the adhesion of sweat, dust, and household stains, making it less prone to dirt growth, easy to clean, and extending the service life of the product.

[0039] 2. The composite material prepared by the PC / ABS composite masterbatch of the present invention has an antibacterial rate of ≥99.2% against Escherichia coli and Staphylococcus aureus, and the surface moisture retention can last for 75 hours, which solves the defects of traditional plastics such as dryness and hardness to the touch, and meets the needs of human skin contact.

[0040] 3. Based on the data from Examples 1, 6, and 7, insufficient maleic anhydride resulted in a low grafting rate and poor interfacial compatibility. This led to increased gaps within the matrix, the precipitation of small molecules, and a sensitization rate of 0.45%. The bonding between the two components was also weak, resulting in a slight decrease in impact strength and tensile strength. Conversely, excessive maleic anhydride left unreacted monomers within the matrix, posing a risk of secondary sensitization. Furthermore, insufficient initiator resulted in incomplete grafting, increased byproducts, and a sensitization rate of 0.49%, with a simultaneous decrease in antibacterial performance.

[0041] 4. Based on the data from Example 1, Comparative Example 8, and Comparative Example 9, without the flexible assistance of dendritic polyglycerol esters in film formation, silanes are unevenly dispersed on the material surface, resulting in film cracking, micropores, a contact angle of only 105.8°, and a reduced moisturizing time of 49 hours. Furthermore, the surface layer cannot lock in the internal moisturizing and antibacterial powders, leading to a significant decrease in long-term performance and a rebound in the sensitization rate to 0.74%. When excessive dendritic polyglycerol is added, organic esters accumulate on the surface, reducing hydrophobicity, while the surface layer becomes too flexible and its abrasion resistance deteriorates. Although the contact angle is relatively high, it is prone to wear and detachment with long-term use, resulting in poor durability.

[0042] It should be understood that the above embodiments are exemplary and are not intended to encompass all possible implementations included in the claims. Various modifications and changes can be made to the above embodiments without departing from the scope of this disclosure. Similarly, the various technical features of the above embodiments can be arbitrarily combined to form other embodiments of the present invention that may not be explicitly described. Therefore, the above embodiments only illustrate several implementations of the present invention and do not limit the scope of protection of this patent.

Claims

1. A low-allergenic PC / ABS composite masterbatch, characterized in that: By weight, it contains the following components: PC resin: 50-70 parts; ABS resin: 20-40 parts; Anti-allergy functional unit: 3-8 parts; Polyurethane elastomer: 1-5 parts; Sodium hyaluronate: 0.5–2 parts; Antibacterial powder: 0.1–1 part; Surface modifier: 0.05–0.3 parts; Auxiliary processing aids: 1.2 to 3.5 parts, wherein the auxiliary processing aids include antioxidants, compatibilizers, and internal lubricants.

2. The low-allergenic PC / ABS composite masterbatch according to claim 1, characterized in that: The anti-allergy functional unit is made by compounding maleic anhydride-grafted ABS and β-glucan cross-linked microspheres at a mass ratio of 2:

1.

3. The low-allergenic PC / ABS composite masterbatch according to claim 2, characterized in that: The preparation method of the anti-allergy functional unit includes the following steps: MAH-g-ABS preparation: ABS resin, maleic anhydride, and initiator are mixed in a certain mass ratio, and reacted in an internal mixer at a constant temperature of 185-190℃ and a speed of 50-60r / min for 25-30min. The mixture is then extruded and granulated to obtain maleic anhydride-grafted ABS. Preparation of β-glucan cross-linked microspheres: β-glucan was dissolved in deionized water to prepare a 4% homogeneous solution, a cross-linking agent was added, and the solution was magnetically stirred at room temperature for 2-2.5 h. Microspheres were then prepared by spray drying. Compound modification: MAH-g-ABS and β-glucan microspheres were mixed at a mass ratio of 2-2.5:1, stirred at high speed for 15-20 minutes, and sieved to obtain the anti-allergy functional unit.

4. The low-allergenic PC / ABS composite masterbatch according to claim 3, characterized in that: In the MAH-g-ABS preparation step, the mass ratio of ABS resin, maleic anhydride, and initiator is 100:6-8:1-1.

2.

5. The low-allergenic PC / ABS composite masterbatch according to claim 1, characterized in that: The preparation method of the surface modifier includes the following steps: Perfluorooctyltriethoxysilane was diluted with anhydrous ethanol at a mass ratio of 1:4 and ultrasonically dispersed to obtain a uniform silane solution. Then, dendritic polyglycerol ester was added and stirred at a constant temperature of 45°C for 1.2-1.5 h for compound modification. Finally, the ethanol solvent was removed by vacuum distillation to obtain the surface modifier.

6. The low-allergenic PC / ABS composite masterbatch according to claim 5, characterized in that: In the preparation method of the surface modifier, the mass ratio of perfluorooctyltriethoxysilane to dendritic polyglycerol ester is 1:1.2-1.

5.

7. The low-allergenic PC / ABS composite masterbatch according to claim 1, characterized in that: The antibacterial powder is selected from nano zinc oxide antibacterial powder, wherein the particle size of the nano zinc oxide antibacterial powder is 30-50 nm.

8. The low-allergenic PC / ABS composite masterbatch according to claim 1, characterized in that: The auxiliary processing aids comprise, by weight: 0.4-1.0 parts of antioxidant 1010, 0.5-1.5 parts of styrene-maleic anhydride compatibilizer, and 0.3-1.0 parts of glyceryl stearate lubricant.

9. A method for preparing a low-allergenic PC / ABS composite masterbatch according to any one of 1 to 8, characterized in that: The preparation steps include the following: Step S1: Add ABS resin to the cyclodextrin inclusion complex carrier, stir at a constant temperature of 70-75℃ for 40-50 minutes, dry the PC resin until the moisture content is ≤0.02%, and sieve for later use. Step S2: The ABS pretreated in Step 1 is fed into a twin-screw extruder, heated and melted, and then molten PC resin is added for shear emulsification. During the process, the screw speed is controlled at 320-350 r / min and the shear pressure is 2.5 MPa. Step S3: Simultaneously add the anti-allergy functional unit, antibacterial powder, sodium hyaluronate, and polyurethane elastomer to the first heating zone of the twin-screw extruder, and mix them at a uniform speed to ensure that the powder is evenly dispersed. Step S4: Add surface modifier to the metering section at the end of the twin-screw extruder, and control the temperature at 200℃ to form a uniform modified film on the surface of the material by utilizing the melt flowability. Step S5: Using a three-stage cooling curve: hold at 210℃ for 5 min → hold at 190℃ for 8 min → cool naturally to room temperature, and then extrude and granulate to obtain the low-allergenic PC / ABS composite masterbatch.

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