Dental floss pick composite material prepared from waste polystyrene and polypropylene

Abstract

The invention relates to the technical field of material recovery, and discloses a floss pick composite material prepared from waste polystyrene and polypropylene, and the floss pick composite material comprises the following components by weight: 5-20% of a waste polystyrene reclaimed material; 30-50% of polypropylene; 10-20% of talcum powder; 5-10% of mesoporous silica; 5-10% of a polyamide elastomer; and 0.1-2% of a compound stabilizer. According to the invention, the polyamide elastomer with a biphase structure and the amino hollow mesoporous silica are introduced, so that the amino functionalization effect is fully exerted, the interaction of the components of the composite material is promoted, a compact compound system is formed, the rigidity of the waste polystyrene and polypropylene composite material is improved, the toughness is optimized, and the molding period of a product is shortened; the production and preparation requirements of the floss pick can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of material recycling, and specifically relates to a dental floss rod composite material prepared from waste polystyrene and polypropylene. Background Art

[0002] With the increase in residents' consumption ability and the continuous popularization of oral health care concepts, Chinese consumers' attention to oral hygiene and daily oral care is also gradually increasing. As an important part of oral care utensils, dental floss may become one of the indispensable necessities in consumers' daily lives. The use of dental floss has been very popular and is deeply welcomed by consumers. In recent years, the market scale of dental floss products has achieved relatively stable growth. As of 2022, the market scale of the Chinese dental floss industry has reached 654 million yuan. It is estimated that the demand for dental floss rod materials is 16,000 tons per year. Among them, the dental floss of the Little Deer Mom brand accounts for 23.90% (3,800 tons of dental floss rod materials), an increase of 8 percentage points compared with 2021; the market share of Watson's dental floss has shrunk from 11.2% in 2021 to 10.5%; the market share of Oral-B dental floss has shrunk from 12% in 2021 to 8.3%.

[0003] According to the current situation of domestic and foreign dental floss rods, in terms of materials, 70% of the main polyethylene fiber materials used in dental floss are used in military fields such as bulletproof vests, bulletproof helmets, bulletproof armor for military facilities and equipment, and aerospace. This wire does not break, does not fluff, the dental floss is smooth, and can easily slide into the tooth gaps. Traditional dental floss rod handles are mainly made of HIPS, ABS, or produced using PP or PP+GF15 materials. Usually, the requirements for materials of dental floss rods are mainly high rigidity, fast molding cycle, and color controllability.

[0004] CN 117659655 A discloses a degradable antibacterial dental floss rod handle. This invention uses two degradable materials, polyglycolic acid and polycaprolactone, as the matrix of the dental floss rod handle, and adds additives such as nanocrystalline whiskers, heat stabilizers, and hydrolysis inhibitors, which can make the dental floss rod prepared later have the functions of biodegradation and antibacterial. CN115028933A discloses a modified grip for interdental brushes with heat resistance deformation ability and its preparation method. This invention mechanically blends syndiotactic polypropylene and foamed polystyrene, which can change the heat resistance and impact resistance of polystyrene, and has good heat-resistant transparent materials, meeting the requirements of the dental floss rod grip for heat resistance deformation ability. Although there have been the above reports on dental floss rod materials, there are no reports on patents and papers regarding the recycling and modification of waste polystyrene for dental floss rod materials. Summary of the Invention

[0005] The present invention relates to a dental floss rod composite material prepared from waste polystyrene and polypropylene, which has excellent material properties and is particularly suitable for dental floss rods that meet the requirements of green environmental protection and low carbon. This material innovatively uses waste polystyrene materials and polypropylene for preparation, and combines technologies for reinforcement, toughening, and improvement of interfacial compatibility, significantly enhancing the overall performance of the composite material.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows: A dental floss rod composite material prepared from waste polystyrene and polypropylene, by weight percentage, comprises the following raw materials: Recycled waste polystyrene 5 - 20%; Polypropylene 30 - 50% Talcum powder 10 - 20% Mesoporous silica 5 - 10% Polyamide elastomer 5 - 10% Compound stabilizer 0.1 - 2%; The recycled waste polystyrene material has a density of 1.04 - 1.08 g / cm 3 , a melt flow rate of 3 - 8 g / 10 min, a flexural modulus of 2000 - 2500 MPa, and a notched Izod impact strength of 4 - 8 kJ / m 2 .

[0007] The polypropylene is one or several blends of homopolypropylene, copolymerized polypropylene, and random copolymerized polypropylene. Preferably, it is homopolypropylene, which has a flexural modulus ≥ 1800 MPa and a melt flow rate of 5 - 20 g / 10 min.

[0008] The inorganic filler is talcum powder, and the D50 particle size distribution range is from 1.5 um to 10 um. Domestic manufacturers such as Guilin Shenba and foreign manufacturers such as Imerys can be selected. Preferably, it is Imerys' T84 talcum powder.

[0009] The mesoporous silica has a particle size distribution range of 10 - 100 nm. The surface of the silica nanoparticles is rich in silanol groups, which is conducive to its surface chemical treatment. By modifying different functional groups, more functions can be imparted to the silica nanoparticles. Currently, relatively common surface modification types include surface amination, carboxylation, mercaptanization, organic chain functionalization, etc. Preferably, it is amino - hollow mesoporous silica, such as 3 - aminopropyltriethoxysilane (APTES), which can be used for amination modification.

[0010] The polyamide elastomer preferably has a density of 1.10 - 1.12 g / cm 3, the melt flow rate is 3 - 15 g / 10 min, and the tensile strength is 30 - 80 MPa. Preferably, the polyamide elastomer material of Xuyang Technology M5511 has excellent tensile strength and elongation at break, and at the same time has a certain high strength.

[0011] The composite stabilizer is an antioxidant mixture, preferably a combination of a hydroxylamine-based phenol-free primary antioxidant and a spirophosphite-based secondary antioxidant. Since waste polystyrene materials are prone to degradation, in order to effectively utilize resources and extend the service life of the recycled polypropylene backfill, it is necessary to add a composite stabilizer. This composite stabilizer can prevent the degradation of waste polystyrene materials during the production process, and at the same time improve the heat resistance of the composite material, effectively meeting the requirements for long-term storage of the composite material.

[0012] Compared with the traditional polypropylene or polystyrene dental floss rod materials technology, the present invention has the following beneficial effects: (1) Recycling waste polystyrene materials, through various modification technologies, the performance of the composite material is not reduced due to the addition of recycled materials, and it can still be used as a composite material for dental floss rods.

[0013] (2) The creative application of amino hollow mesoporous silica in the present invention enables the ultrafine talc powder T84 and polyamide elastomer to be effectively loaded and dispersed in the internal hollow region and on the surface of the hollow mesoporous silica, so that the composite material obtains high rigidity, good toughness and a short molding cycle.

[0014] (3) The method for preparing the waste polystyrene / polypropylene composite in the present invention uses a twin-screw extrusion process equipment, which has the advantages of simple process, continuity, high production efficiency, and stable product quality. Detailed implementation manners

[0015] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following examples are used to further explain the present invention in detail. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention. Those skilled in the art make modifications or equivalent replacements based on the understanding of the technical solutions of the present invention, and without departing from the spirit and scope of the technical solutions of the present invention, they should all be covered within the protection scope of the present invention.

[0016] The raw materials used in the detailed implementation manners are all purchased from the market, and the specific sources are shown in Table 1 below: Waste Polystyrene Produced by Qingdao Hailvyuan Recycling Technology Co., Ltd., China Polypropylene CNOOC Shell HP840N-Z Talcum Powder IMERYS T84 Talcum Powder, Shenba Talcum Powder, Guilin, China Mesoporous Silica Amino Hollow Silica XFF29-1, Carboxyl Hollow Silica Produced by Xianfeng Nano Elastomer Polyamide Elastomer: Xuyang Technology M5511; SEBS Elastomer: Kraton 6154, USA Primary Antioxidant 420 Hydroxylamine-Based Phenol-Free Primary Antioxidant, Revonox® 420V by Chitai, Taiwan, China Secondary Antioxidant 608 608 is a Spirophosphite-Based Secondary Antioxidant, Revonox® 608 by Chitai, Taiwan, China Irganox 1010 Ciba Specialties, Switzerland, Chemical Name: Pentaerythritol Tetrakis[3-(3,5-Di-tert-butyl-4-hydroxyphenyl)Propionate] Irganox 168 Ciba Specialties, Switzerland, Chemical Name: Tris(2,4-Di-tert-butyl)phenyl Phosphite The test methods for various properties of the materials are as follows Density: ISO 1183; Tensile strength: ISO 527; Flexural strength and flexural modulus: ISO 178; Notched impact strength: ISO 179; Melt flow rate: ISO 1133, at a temperature of 230 °C and a load of 2.16 KG; Injection molding time, calculated according to a sample with an injection molding size of 210 * 140 * 2.8 mm, and the injection molding equipment used is the LK injection molding machine PT160.

[0017] According to the formula in Table 2, the recycled polypropylene from waste washing machine barrels, polypropylene, isotactic metallocene polypropylene, talc powder, toughening agent, compatibilizer, composite photothermal stabilizer, carbon aerogel are taken, and a scratch-resistant agent and a colorant are added. After high-speed mixing in a high-speed mixer for 2 minutes, they are added from the main feeding hopper; the temperatures of the twin-screw extruder from the feeding section to the die head are in sequence: 180 °C - 200 °C, 180 °C - 200 °C, 180 °C - 200 °C, 180 °C - 200 °C, 190 °C - 210 °C, 190 °C - 210 °C, 190 °C - 210 °C, 190 °C - 210 °C, and the temperature of the die head is 210 °C. After extrusion, it undergoes water cooling and pelletizing to obtain a polypropylene composite material.

[0018] Component Unit: KG Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 HIPS 825 99.5 PP HP840N-Z 69.5 59.5 59.5 59.5 59.5 59.5 59.5 59.5 99.5 Waste Polystyrene 10 20 15 15 15 15 15 15 T84 Talcum Powder 20 20 20 20 15 15 15 Shenba Talcum Powder, Guilin 15 Amino Hollow Silica XFF29-1 5 5 5 Carboxyl Hollow Silica 5 Polyamide Elastomer M5511 5 5 5 5 SEBS Elastomer 6154 5 5 Primary Antioxidant 420 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Secondary Antioxidant 608 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Irganox 1010 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Irganox 168 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 The pellets of Examples 1 - 8 and Comparative Examples 1 - 2 are prepared into test specimens by an injection molding machine for mechanical property testing and molding cycle testing, and the results are shown in Table 3.

[0019] Properties Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparative Example 1 Comparative Example 2 <![CDATA[Density (g / cm 3 )]]> 1.042 1.053 1.057 1.052 1.058 1.053 1.058 1.058 1.042 0.901 Flexural Strength (MPa) 49.1 47.4 49.3 47.9 51.2 48.2 50.8 50.0 45.2 48.6 Flexural Modulus (MPa) 2672 2653 2754 2478 2868 2535 2817 2790 2319 1845 Tensile Strength (MPa) 39.9 39.2 40.1 37.2 40.7 38.1 40.5 40.3 22 5 38.9 <![CDATA[Notched impact strength (kJ / m 2 )]]> 4.1 2.9 4.4 5.9 5 6.2 4.8 4.6 7.1 5.3 Melt Flow Rate (g / 10min) 10.7 9.4 8.4 8.2 9.1 8.7 9.0 8.6 4.5 12.9 Molding Time 26 20 23 27 22 25 22 23 18 33 Percentage Reduction in Molding Time 32% 39% 30% 18% 33% 24% 32% 31% / 0 The following points can be seen from Examples 1 - 6: When 20% of recycled polystyrene is added, the properties of the composite material decrease significantly. This may be because the properties of the recycled polystyrene material have decreased to a certain extent, and in addition, the compatibility between polypropylene and polystyrene is poor.

[0020] After introducing polyamide elastomer and SEBS elastomer into the composite material, the addition of both has a positive effect on improving the impact performance of the material. Due to the good compatibility shown between SEBS and polystyrene and polypropylene, its enhancement of the impact strength is particularly significant, but this improvement is accompanied by a significant decrease in the rigidity of the material. In contrast, polyamide elastomer, as a product of block copolymerization of polyamide with ether or ester compounds, not only does not weaken the rigidity of the composite material based on polypropylene substrate, but instead achieves a dual improvement in rigidity and toughness. This unique performance is attributed to the biphasic structure inside the polyamide elastomer: among them, the polyamide chain segments act as the hard phase, providing excellent rigidity; while the ether or ester chain segments act as the soft phase, endowing the material with elastic properties, enabling the composite material to have both high rigidity and enhanced toughness.

[0021] The introduction of amino hollow mesoporous silica material into the system not only significantly enhances the rigidity of the material, but also optimizes its toughness performance. This material, with its excellent stability and highly permeable mesoporous shell, can efficiently load and evenly disperse ultrafine T84 talc powder. The optimization of the dispersion mechanism benefits from the synergistic effect of amino functional modification and mesoporous structure, which enables T84 talc powder to be highly dispersed in the pores of amino hollow mesoporous silica, thereby forming numerous crystal nuclei, accelerating the crystallization process of polypropylene (PP), and improving the crystallinity of PP, thereby effectively enhancing the rigidity of the composite material. In addition, the accelerated crystallization speed also shortens the molding cycle of the dental floss stick, further improving production efficiency. On the other hand, amino functionalization not only promotes the interaction between ultrafine T84 talc powder and the surface of hollow mesoporous silica, optimizes its dispersibility in the molten state, but also enhances the compatibility between amino-modified silica and polyamide elastomers. This improvement in compatibility allows the polyamide elastomer, amino hollow silica and ultrafine T84 talc to form a tighter compound system, thereby achieving an overall improvement in the performance of the composite material.

Claims

1. A dental floss rod composite material prepared from waste polystyrene and polypropylene, characterized in that, By weight percentage, it includes the following raw materials: Recycled waste polystyrene: 5 - 20%; Polypropylene: 30 - 50% Talc powder: 10 - 20% Mesoporous silica: 5 - 10% Polyamide elastomer: 5 - 10% Compound stabilizer: 0.1 - 2%.

2. The dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, wherein The recycled waste polystyrene material has a density of 1.04 - 1.08 g / cm 3 , a melt flow rate of 3 - 8 g / 10 min, a flexural modulus of 2000 - 2500 MPa, and a notched Izod impact strength of 4 - 8 kJ / m 2 .

3. The dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, wherein, The polypropylene described is one or several blends of homopolypropylene, copolymer polypropylene, and random copolymer polypropylene, with a density of 0.89 - 0.91 g / cm 3 , and a melt flow rate of 3 - 30 g / 10 min.

4. A dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, characterized in that, The inorganic filler is talc powder, and the D50 particle size distribution range is from 1.5 μm to 10 μm.

5. The dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, wherein, The mesoporous silica has a particle size distribution range of 10 - 100 nanometers.

6. The dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, wherein, The surface of the mesoporous silica is modified by amination, carboxylation, and mercaptanization.

7. The dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, wherein, The polyamide elastomer described has a density of 1.10 to 1.12 g / cm 3 , a melt flow rate of 3 - 15 g / 10 min, and a tensile strength of 30 - 80 MPa.

8. The dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, wherein, The compound stabilizer is selected from at least one of hydroxylamine - type phenolic - free primary antioxidants, phosphite - type auxiliary antioxidants, and hindered amine light stabilizers.

9. The preparation method of a dental floss rod composite material prepared from waste polystyrene and polypropylene according to claim 1, characterized in that, It includes the following steps: uniformly mixing the recycled waste polystyrene, polypropylene, talc powder, silica, polyamide elastomer, and compound stabilizer, adding them into a blending device for melt blending at 180 - 260 °C, cooling, pelletizing, and drying to obtain the composite material.

10. The dental floss rod composite material prepared from recycled waste polystyrene and polypropylene according to any one of claims 1 - 9 is applicable to dental floss rods that meet the requirements of low - carbon environmental protection.