A rubber-modified soft plastic and its preparation method

Abstract

The present invention belongs to the field of plastic processing technology, and in particular relates to a rubber-modified soft plastic and a preparation method thereof. The present invention uses natural rubber and butyl rubber to modify polypropylene. The addition of natural rubber and butyl rubber forms chemical bonds with the polypropylene, enabling the originally brittle polypropylene to absorb energy through deformation of the rubber phase when subjected to external impact, reducing cracking and damage. The polypropylene also provides support for the rubber, limiting excessive deformation of the rubber. The composite filler uses SMA-modified HPMC, so that when the modified HPMC molecules are adsorbed onto the surface of BaNbO3, they form a stable coating structure, preventing agglomeration between BaNbO3 particles. The modified HPMC can form chemical bonds with the BaNbO3, strengthening the interface between the BaNbO3 and the matrix and effectively transferring stress from the matrix to the BaNbO3.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic processing, and in particular relates to a rubber-modified soft plastic and a preparation method thereof. Background Art

[0002] Plastics have high rigidity and hardness, and good processing properties. Blending rubber with plastics to improve their properties not only improves the plastic's processing properties but also increases the rubber's strength, resulting in even better performance. Soft plastics generally refer to thermoplastics, polymer materials with flexibility and plasticity. These materials are injection molded and can be reprocessed and reused. These plastics are inexpensive, soft, and easy to construct, making them widely used in various fields.

[0003] Soft plastics are difficult to restore to their original shape after deformation and have low elasticity. Products made solely from rubber lack brittleness, creating a balance between the two. With the rapid development of technology, the use of rubber to modify soft plastics is becoming increasingly common. While these composite materials often address strength and toughness issues, their antibacterial, wear, and aging resistance remain poor, leading to cracking and aging. This leads to poor durability and a short service life. Therefore, developing a rubber-modified soft plastic with high strength, strong wear resistance, strong antibacterial properties, strong aging resistance, and long durability is a pressing technical challenge. Summary of the Invention

[0004] In view of the deficiencies of the prior art, the present invention provides a rubber-modified soft plastic and a preparation method thereof. The present invention uses natural rubber and butyl rubber to modify polypropylene, forming chemical bonds between the natural rubber and butyl rubber and the polypropylene, thereby enhancing interfacial interaction and strengthening bonding strength. The modified HPMC in the composite filler can form a good bonding layer at the interface of the polypropylene and rubber, thereby enhancing bonding strength between the two. BaNbO3 can improve the hardness and thermal stability of the material. When dispersed in the polypropylene and rubber matrix, it can serve as a physical crosslinking point to restrict the movement of molecular chains, thereby improving the strength and modulus of the material and also improving the dielectric properties of the material. BaNbO3 powder plays a role in reinforcing the skeleton in the composite filler, thereby improving the overall strength and hardness of the material. After HPMC is combined with BaNbO3 powder, the brittleness of BaNbO3 is improved, so that the composite filler has better toughness while maintaining a certain strength, thereby improving the material's ability to resist external force damage. At the same time, HPMC interacts with groups such as hydroxyl groups in HPMC to form a stronger interfacial bond between BaNbO3 and HPMC. This strengthened interfacial bond can more effectively transmit stress, so that when the composite filler is subjected to external force, the various components can synergize with each other, thereby further enhancing the mechanical properties of the material.

[0005] In order to achieve the above technical objectives, the technical solutions adopted by the present invention are as follows:

[0006] The present invention provides a rubber-modified soft plastic, which is prepared from the following raw materials in parts by weight: 60-90 parts of polypropylene, 10-40 parts of natural rubber, 5-20 parts of butyl rubber, 10-30 parts of composite filler, 1-10 parts of cross-linking agent, 3-15 parts of compatibilizer, 25-40 parts of plasticizer, 4-15 parts of ultraviolet light absorber, and 20-50 parts of flame retardant;

[0007] Preferably, the cross-linking agent is hydrogen-containing silicone oil or JT-509 dealcohol-type cross-linking agent.

[0008] Preferably, the compatibilizer is one or more of KH-550 (γ-aminopropyltriethoxysilane), TEOS (tetraethyl orthosilicate), and EVA (ethylene-vinyl acetate copolymer).

[0009] Preferably, the plasticizer is epoxidized soybean oil or phenolic resin.

[0010] Preferably, the ultraviolet light absorber is benzotriazole.

[0011] Preferably, the flame retardant is zinc borate.

[0012] The raw materials for preparing the composite filler are: HPMC (hydroxypropyl methylcellulose), BaCl2·5H2O, Nb2O5, curcumin and SMA (styrene-maleic anhydride copolymer); the mass ratio of HPMC, BaCl2·5H2O, Nb2O5 and curcumin is 20-30:220:100:1;

[0013] The preparation method of the composite filler specifically comprises the following steps:

[0014] (1) HPMC was added to deionized water and stirred in a water bath at 50-60 °C until HPMC was completely dissolved to form a uniform HPMC solution. The concentration of the HPMC solution was controlled to be 2-5 wt%. SMA was added to the HPMC solution with a mass ratio of SMA to HPMC solution of 1-5:100. The mixture was stirred for 2 h to obtain a mixed solution. The mixed solution was transferred to a reactor and reacted at 120 °C for 6 h to achieve the modification of HPMC. The modified HPMC was then washed and dried to obtain the modified HPMC.

[0015] (2) Weighing a composite base, mixing the composite base with BaCl2·5H2O and Nb2O5 at a mass ratio of 15:1, placing the composite base in an autoclave, reacting at 200°C for 24 h to obtain a product, neutralizing the product with dilute hydrochloric acid (pH = 1), then washing the product with deionized water and ethanol alternately, and drying it in an oven to obtain BaNbO3 powder;

[0016] (3) Add the modified HPMC to deionized water to control the concentration to 3-8 wt% to obtain a modified HPMC solution, add the BaNbO3 powder to the modified HPMC solution, stir and mix to ensure uniform dispersion, and form a mixture A;

[0017] (4) Adding curcumin to the mixture A obtained in step (3), stirring and mixing to ensure uniform dispersion, to form a mixture B;

[0018] (5) Add photoinitiator 1173 (2-hydroxy-2-methyl-1-phenyl-1-propanone) to the mixture B obtained in step (4) in a mass ratio of 1:0.01-0.03, react under 365 nm ultraviolet light for 1 h to perform photopolymerization reaction to obtain HPMC / BaNbO3 precursor, solidify the HPMC / BaNbO3 precursor, and then immerse it in deionized water for 24 h to remove unreacted residues, and then put it into an oven at 40-50 ° C to dry to obtain a composite filler.

[0019] Furthermore, the composite alkali is prepared by mixing sodium hydroxide and potassium hydroxide in an equal molar ratio of 1:1.

[0020] The present invention also provides a method for preparing a rubber-modified soft plastic, which specifically comprises the following steps:

[0021] S1, weighing polypropylene, natural rubber, butyl rubber and a compatibilizer in parts by weight, putting them into an internal mixer and mixing them to obtain a blend;

[0022] S2, adding a crosslinking agent by weight to the blend obtained in step S1, kneading, adding a composite filler, and kneading again to uniformly mix the components to obtain a mixed masterbatch;

[0023] S3, adding the mixed masterbatch obtained in step S2 to a two-roll mill for refining, and then adding a plasticizer, an ultraviolet light absorber and a flame retardant to obtain a rubber compound;

[0024] S4, using a twin-screw extruder to extrude the rubber mixture obtained in step S3, cooling it at room temperature, and drying it to obtain a rubber-modified soft plastic.

[0025] Furthermore, the initial temperature of the internal mixer in step S1 is 60° C., the rotor speed is 60-100 rpm, and the mixing time is 5-10 min.

[0026] Furthermore, the mixing time in step S2 is 2-10 min, and the secondary mixing time is 5-20 min.

[0027] Furthermore, the temperature of the open refining in step S3 is set to 90-120° C. and the time is 10-30 min.

[0028] Furthermore, the twin-screw extruder described in step S4 has a temperature set to 50-90° C. and a rotation speed set to 100-200 rpm.

[0029] Furthermore, the model of the internal mixer is RM-200C, purchased from Harbin Harpu Electric Technology Co., Ltd.; the model of the double-roll mill is 160, purchased from Guangdong Zhanjiang Rubber and Plastic Machinery Factory; the model of the twin-screw extruder is SHJ-20, purchased from Nanjing Jieente Electromechanical Co., Ltd.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present invention uses natural rubber and butyl rubber to modify polypropylene. The addition of natural rubber and butyl rubber forms chemical bonds with the polypropylene, enhancing interfacial interactions. This allows the originally brittle polypropylene to absorb energy through deformation of the rubber phase when subjected to external impact, reducing the possibility of cracking and damage. The polypropylene also provides support for the rubber, limiting excessive deformation, improving the overall dimensional stability and load-bearing capacity of the material, and imparting both rigidity and flexibility. The HPMC in the composite filler forms a good bonding layer at the interface between the polypropylene and rubber, enhancing the bonding between the two. BaNbO3 is dispersed in the polypropylene and rubber matrices, acting as physical crosslinking points to limit the movement of molecular chains, increasing the material's strength and modulus, while also improving its dielectric properties. The composite filler uses HPMC modified with SMA. SMA promotes the cross-linking structure of the originally linear molecular chains of HPMC, increasing the steric hindrance effect of the molecular chains. This allows the modified HPMC molecules to better interweave and entangle with each other when adsorbed onto the surface of BaNbO3, forming a stable coating structure, preventing the agglomeration of BaNbO3 particles, and making BaNbO3 highly uniformly dispersed in the rubber-modified soft plastic as a whole, avoiding local performance differences, and improving the stability and consistency of the overall performance of the material. The modified HPMC can form a chemical bond with BaNbO3, the strength of which is much higher than that of hydrogen bonds and van der Waals forces, making the interface between BaNbO3 and the rubber-modified soft plastic as a whole more firmly bonded, and can effectively transfer stress, so that stress can be transferred from the rubber-modified soft plastic as a whole to BaNbO3. When the material is subjected to external forces, the interfacial bonding force strengthened by HPMC precisely and efficiently transfers stress from the rubber-modified soft plastic to the BaNbO3, promoting synergistic deformation. This process effectively interferes with and blocks the crack propagation path, making the energy distribution within the material more uniform and maintaining its toughness. BaNbO3 is evenly dispersed throughout the rubber-modified soft plastic, and the modified HPMC forms a good interfacial bridge, allowing charge to be smoothly conducted and stored within the material, achieving excellent electrical properties. When subjected to force, stress is evenly distributed throughout the material system, avoiding damage caused by localized stress concentration and ensuring the material's mechanical properties. During photopolymerization, the curcumin added to the composite filler interacts with the system formed by HPMC and BaNbO3. This not only facilitates the photopolymerization reaction and stabilizes the composite filler's structure, but also absorbs ultraviolet light during subsequent use, reducing damage to the composite filler and its applied materials and improving the material's resistance to light aging. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic cross-sectional view of a microscopic model of the rubber-modified soft plastic prepared in the present invention;

[0033] Figure 2A line graph showing the limiting oxygen index of the rubber-modified soft plastic prepared in the present invention;

[0034] Figure 3 This is a bar chart showing the aging resistance of the rubber-modified soft plastic prepared in the present invention. DETAILED DESCRIPTION

[0035] In order to enable those skilled in the art to better understand the technical solution of the present invention and to make the above-mentioned features, purposes and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with examples. The examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0037] In the following examples, unless otherwise specified, conventional methods are used. The materials used in the following examples, unless otherwise specified, are all commercially available new materials, including polypropylene, CAS No. 9003-07-0, molecular weight: 80,000-90,000, melt index: 0.3 g / 10 min, purchased from Sinopec; natural rubber, CAS No. 9006-04-6, purchased from Shanghai Macklin Reagent Co., Ltd.; butyl rubber, model: 1751, purchased from Beijing Yanshan Petrochemical Co., Ltd.; HPMC, 2% viscosity: 6 mPa.s, methoxy propyl: 28-30%; hydroxypropyl: 7.0-12%, purchased from Aladdin Reagent Co., Ltd.; curcumin, product number: C805204, reagent grade, purchased from Shanghai Maclean Reagent Co., Ltd.; SMA, maleic anhydride (MAH) content is 12.5%, purchased from Shanghai Petrochemical Research Institute; benzotriazole, CAS number: 95-14-7, product number: H801875, 99%, purchased from Shanghai Maclean Reagent Co., Ltd.; phenolic resin, CAS number: 9003-35-4, product number: P832682, BR, purchased from Shanghai Maclean Reagent Co., Ltd.

[0038] Example 1: This example provides a rubber-modified soft plastic, which is prepared from the following raw materials in parts by weight: 60 parts of polypropylene, 40 parts of natural rubber, 5 parts of butyl rubber, 10 parts of composite filler, 1 part of hydrogenated silicone oil, 3 parts of KH-550, 25 parts of epoxy soybean oil, 4 parts of benzotriazole, and 20 parts of zinc borate;

[0039] The raw materials for preparing the composite filler are: HPMC, BaCl2·5H2O, Nb2O5, curcumin and SMA; the mass ratio of HPMC, BaCl2·5H2O, Nb2O5 and curcumin is 20:220:100:1;

[0040] The preparation method of the composite filler specifically comprises the following steps:

[0041] (1) 30 parts of HPMC were added to deionized water and stirred at 500 rpm in a 50 ℃ water bath until HPMC was completely dissolved to form a uniform HPMC solution. The concentration of the HPMC solution was controlled to be 2 wt%. SMA was added to the HPMC solution with a mass ratio of SMA to HPMC solution of 1:100. The mixture was stirred at 500 rpm for 2 h to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and reacted at 120 ℃ for 6 h to achieve the modification of HPMC. The mixture was washed alternately with deionized water and anhydrous ethanol three times and dried in a 60 ℃ oven for 12 h to obtain modified HPMC.

[0042] (2) Sodium hydroxide and potassium hydroxide were mixed in an equimolar ratio of 1:1 to form a composite hydroxide. Subsequently, the composite hydroxide was mixed with BaCl2·5H2O and Nb2O5 at a mass ratio of 15:1. The mixture was placed in an autoclave and reacted at 200°C for 24 h to obtain a product. The product was neutralized with dilute hydrochloric acid (pH = 1). The product was then rinsed alternately with deionized water and ethanol three times and dried in an oven at 70°C to obtain BaNbO3 powder.

[0043] (3) Modified HPMC was added to deionized water at a concentration of 3 wt% to obtain a modified HPMC solution. BaNbO3 powder was added to the modified HPMC solution, and the solution was placed in an ultrasonic cleaning machine and mixed at 240 W for 1 h to ensure uniform dispersion to form a mixture A.

[0044] (4) Adding curcumin to the mixture A obtained in step (3), stirring at 800 rpm to ensure uniform dispersion, to form a mixture B;

[0045] (5) Adding photoinitiator 1173 to the mixture B obtained in step (4) with a mass ratio of mixture B to photoinitiator 1173 being 1:0.01, the mixture was reacted under 365 nm ultraviolet light for 1 h to perform a photopolymerization reaction to obtain an HPMC / BaNbO3 precursor. The HPMC / BaNbO3 precursor was cured at room temperature for 12 h, then immersed in deionized water for 24 h to remove unreacted residues, and then placed in an oven at 40 °C for drying to obtain a composite filler.

[0046] This embodiment also provides a method for preparing a rubber-modified soft plastic, which specifically includes the following steps:

[0047] S1, weigh 60 parts of polypropylene, 40 parts of natural rubber, 5 parts of butyl rubber and 3 parts of KH-550, put them into an internal mixer and mix them for 5 minutes. The initial temperature of the internal mixer is 60 °C and the rotor speed is 60 rpm to obtain a blend;

[0048] S2, weighing 1 part of hydrogen-containing silicone oil, adding it to the blend obtained in step S1, continuing to mix in an internal mixer for 2 minutes, adding 10 parts of composite filler, and performing a second mixing for 20 minutes to mix all the components uniformly to obtain a mixed masterbatch;

[0049] S3, placing the mixed masterbatch obtained in step S2 into a two-roll mill for milling for 10 minutes, adding 25 parts of epoxy soybean oil, 4 parts of benzotriazole and 20 parts of zinc borate, mixing evenly, setting the temperature to 90° C., and obtaining a rubber compound;

[0050] S4, using a twin-screw extruder to extrude the rubber mixture obtained in step S3, setting the temperature of the twin-screw extruder to 50° C. and the speed to 100 rpm, cooling at room temperature, and drying to obtain a rubber-modified soft plastic.

[0051] Example 2: This example provides a rubber-modified soft plastic, which is prepared from the following raw materials in parts by weight: 70 parts of polypropylene, 30 parts of natural rubber, 10 parts of butyl rubber, 18 parts of composite filler, 2 parts of JT-509 dealcoholization crosslinking agent, 7 parts of compatibilizer, 30 parts of phenolic resin, 8 parts of benzotriazole, and 30 parts of zinc borate;

[0052] The compatibilizers are KH-550 and TEOS, and the molar ratio of the compatibilizers is 1:1.

[0053] The raw materials for preparing the composite filler are: HPMC, BaCl2·5H2O, Nb2O5, curcumin and SMA; the mass ratio of HPMC, BaCl2·5H2O, Nb2O5 and curcumin is 24:220:100:1;

[0054] The preparation method of the composite filler specifically comprises the following steps:

[0055] (1) 30 parts of HPMC were added to deionized water and stirred at 500 rpm in a water bath at 55 °C until HPMC was completely dissolved to form a uniform HPMC solution. The concentration of the HPMC solution was controlled to be 3 wt%. SMA was added to the HPMC solution with a mass ratio of SMA to HPMC solution of 2:100. The mixture was stirred at 500 rpm for 2 h to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and reacted at 120 °C for 6 h to achieve the modification of HPMC. The mixture was washed alternately with deionized water and anhydrous ethanol three times and dried in an oven at 60 °C for 12 h to obtain modified HPMC.

[0056] (2) Sodium hydroxide and potassium hydroxide were mixed in an equimolar ratio of 1:1 to form a composite hydroxide. Subsequently, the composite hydroxide was mixed with BaCl2·5H2O and Nb2O5 at a mass ratio of 15:1. The mixture was placed in an autoclave and reacted at 200°C for 24 h to obtain a product. The product was neutralized with dilute hydrochloric acid (pH = 1). The product was then rinsed alternately with deionized water and ethanol three times and dried in an oven at 70°C to obtain BaNbO3 powder.

[0057] (3) Add modified HPMC to deionized water to control the concentration to 5 wt% to obtain a modified HPMC solution. Add BaNbO3 powder to the modified HPMC solution, place it in an ultrasonic cleaning machine, and mix it at 240 W for 2 h to ensure uniform dispersion to form a mixture A.

[0058] (4) Adding curcumin to the mixture A obtained in step (3), stirring at 800 rpm to ensure uniform dispersion, to form a mixture B;

[0059] (5) Adding photoinitiator 1173 to the mixture B obtained in step (4) with a mass ratio of mixture B to photoinitiator 1173 being 1:0.015, the mixture was reacted under 365 nm ultraviolet light for 1 h to perform a photopolymerization reaction to obtain an HPMC / BaNbO3 precursor. The HPMC / BaNbO3 precursor was cured at room temperature for 12 h, then immersed in deionized water for 24 h to remove unreacted residues, and then placed in an oven at 50°C for drying to obtain a composite filler.

[0060] This embodiment also provides a method for preparing a rubber-modified soft plastic, which specifically includes the following steps:

[0061] S1, weigh 70 parts of polypropylene, 30 parts of natural rubber, 10 parts of butyl rubber and 7 parts of compatibilizer, put them into an internal mixer and mix them for 7 minutes. The initial temperature of the internal mixer is 60 °C and the rotor speed is 75 rpm to obtain a blend;

[0062] S2, weighing 2 parts of JT-509 dealcoholization crosslinking agent, adding them to the blend obtained in step S1, and continuing to mix in an internal mixer for 5 minutes, adding 18 parts of composite filler, and mixing again for 10 minutes to mix all the components evenly to obtain a mixed masterbatch;

[0063] S3, placing the mixed masterbatch obtained in step S2 into a two-roll mill for milling for 15 minutes, then adding 30 parts of phenolic resin, 8 parts of benzotriazole and 30 parts of zinc borate, mixing them evenly, setting the temperature to 100° C., and obtaining a rubber compound;

[0064] S4, using a twin-screw extruder to extrude the rubber mixture obtained in step S3, setting the temperature of the twin-screw extruder to 60° C. and the speed to 130 rpm, cooling at room temperature, and drying to obtain a rubber-modified soft plastic.

[0065] Example 3: This example provides a rubber-modified soft plastic, which is prepared from the following raw materials in parts by weight: 80 parts of polypropylene, 20 parts of natural rubber, 15 parts of butyl rubber, 20 parts of composite filler, 6 parts of JT-509 dealcoholization crosslinking agent, 10 parts of TEOS, 35 parts of phenolic resin, 10 parts of benzotriazole, and 40 parts of zinc borate;

[0066] The raw materials for preparing the composite filler are: HPMC, BaCl2·5H2O, Nb2O5, curcumin and SMA; the mass ratio of HPMC, BaCl2·5H2O, Nb2O5 and curcumin is 25:220:100:1;

[0067] The preparation method of the composite filler specifically comprises the following steps:

[0068] (1) 40 parts of HPMC were added to deionized water and stirred at 500 rpm in a water bath at 60 °C until HPMC was completely dissolved to form a uniform HPMC solution. The concentration of the HPMC solution was controlled to be 4 wt%. SMA was added to the HPMC solution with a mass ratio of SMA to HPMC solution of 3:100. The mixture was stirred at 500 rpm for 2 h to obtain a mixed solution. The mixed solution was transferred to a polytetrafluoroethylene-lined high-pressure reactor and reacted at 120 °C for 6 h to achieve the modification of HPMC. The mixture was washed alternately with deionized water and anhydrous ethanol three times and dried in a 60 °C oven for 12 h to obtain modified HPMC.

[0069] (2) Sodium hydroxide and potassium hydroxide were mixed in an equimolar ratio of 1:1 to form a composite hydroxide. Subsequently, the composite hydroxide was mixed with BaCl2·5H2O and Nb2O5 at a mass ratio of 15:1. The mixture was placed in an autoclave and reacted at 200°C for 24 h to obtain a product. The product was neutralized with dilute hydrochloric acid (pH = 1). The product was then rinsed alternately with deionized water and ethanol three times and dried in an oven at 70°C to obtain BaNbO3 powder.

[0070] (3) Modified HPMC was added to deionized water at a concentration of 6 wt% to obtain a modified HPMC solution. BaNbO3 powder was added to the modified HPMC solution, and the solution was placed in an ultrasonic cleaning machine and mixed at 240 W for 2.5 h to ensure uniform dispersion to form a mixture A.

[0071] (4) Adding curcumin to the mixture A obtained in step (3), stirring at 800 rpm to ensure uniform dispersion, to form a mixture B;

[0072] (5) Adding photoinitiator 1173 to the mixture B obtained in step (4) in a mass ratio of mixture B to photoinitiator 1173 of 1:0.02, the mixture was reacted under 365 nm ultraviolet light for 1 h to perform a photopolymerization reaction to obtain an HPMC / BaNbO3 precursor. The HPMC / BaNbO3 precursor was cured at room temperature for 12 h, then immersed in deionized water for 24 h to remove unreacted residues, and then placed in an oven at 50 °C for drying to obtain a composite filler.

[0073] This embodiment also provides a method for preparing a rubber-modified soft plastic, which specifically includes the following steps:

[0074] S1, weigh 80 parts of polypropylene, 20 parts of natural rubber, 15 parts of butyl rubber and 10 parts of TEOS, put them into an internal mixer and mix them for 9 minutes at an initial temperature of 60°C and a rotor speed of 90 rpm to obtain a blend;

[0075] S2, weighing 6 parts of JT-509 dealcoholization crosslinking agent, adding it to the blend obtained in step S1, and continuing to mix in an internal mixer for 7 minutes, adding 20 parts of composite filler, and mixing again for 15 minutes to mix all the components evenly to obtain a mixed masterbatch;

[0076] S3, placing the mixed masterbatch obtained in step S2 into a two-roll mill for milling for 20 minutes, then adding 35 parts of phenolic resin, 10 parts of benzotriazole and 40 parts of zinc borate, mixing evenly, setting the temperature to 110° C., to obtain a rubber compound;

[0077] S4, extruding the rubber mixture obtained in step S3 using a twin-screw extruder, setting the temperature of the twin-screw extruder to 70° C. and the speed to 160 rpm, cooling at room temperature, and drying to obtain a rubber-modified soft plastic.

[0078] Example 4: This example provides a rubber-modified soft plastic, which is prepared from the following raw materials in parts by weight: 90 parts of polypropylene, 10 parts of natural rubber, 20 parts of butyl rubber, 30 parts of composite filler, 10 parts of JT-509 dealcoholization crosslinking agent, 15 parts of EVA, 40 parts of phenolic resin, 15 parts of benzotriazole, and 50 parts of zinc borate;

[0079] The raw materials for preparing the composite filler are: HPMC, BaCl2·5H2O, Nb2O5, curcumin and SMA; the mass ratio of HPMC, BaCl2·5H2O, Nb2O5 and curcumin is 30:220:100:1;

[0080] The preparation method of the composite filler specifically comprises the following steps:

[0081] (1) Add 50 parts of HPMC to deionized water and stir at 500 rpm in a water bath at 60 ℃ until HPMC is completely dissolved to form a uniform HPMC solution. The concentration of the HPMC solution is controlled at 5 wt%. SMA is added to the HPMC solution with a mass ratio of SMA to HPMC solution of 5:100. Stir at 500 rpm for 2 h to obtain a mixed solution. The mixed solution is transferred to a polytetrafluoroethylene-lined high-pressure reactor and reacted at 120 ℃ for 6 h to achieve the modification of HPMC. The mixture is washed alternately with deionized water and anhydrous ethanol three times and dried in a 60 ℃ oven for 12 h to obtain modified HPMC.

[0082] (2) Sodium hydroxide and potassium hydroxide were mixed in an equimolar ratio of 1:1 to form a composite hydroxide. Subsequently, the composite hydroxide was mixed with BaCl2·5H2O and Nb2O5 at a mass ratio of 15:1. The mixture was placed in an autoclave and reacted at 200°C for 24 h to obtain a product. The product was neutralized with dilute hydrochloric acid (pH = 1). The product was then rinsed alternately with deionized water and ethanol three times and dried in an oven at 70°C to obtain BaNbO3 powder.

[0083] (3) Modified HPMC was added to deionized water at a concentration of 8 wt% to obtain a modified HPMC solution. BaNbO3 powder was added to the modified HPMC solution, and the solution was placed in an ultrasonic cleaning machine and mixed at 240 W for 3 h to ensure uniform dispersion to form a mixture A.

[0084] (4) Adding curcumin to the mixture A obtained in step (3), stirring at 800 rpm to ensure uniform dispersion, to form a mixture B;

[0085] (5) Add photoinitiator 1173 to the mixture B obtained in step (4) in a mass ratio of mixture B to photoinitiator 1173 of 1:0.03, react under 365 nm ultraviolet light for 1 h to perform photopolymerization reaction to obtain HPMC / BaNbO3 precursor, cure the HPMC / BaNbO3 precursor at room temperature for 12 h, then immerse in deionized water for 24 h to remove unreacted residues, and then dry in an oven at 50 °C to obtain a composite filler.

[0086] This embodiment also provides a method for preparing a rubber-modified soft plastic, which specifically includes the following steps:

[0087] S1, 90 parts of polypropylene, 10 parts of natural rubber, 20 parts of butyl rubber and 15 parts of EVA were weighed and placed in an internal mixer for mixing for 10 min at an initial temperature of 60°C and a rotor speed of 100 rpm to obtain a blend;

[0088] S2, weighing 10 parts of JT-509 dealcoholization crosslinking agent, adding it to the blend obtained in step S1, and continuing to mix in an internal mixer for 10 minutes, adding 30 parts of composite filler, and mixing again for 20 minutes to mix all the components evenly to obtain a mixed masterbatch;

[0089] S3, placing the mixed masterbatch obtained in step S2 into a two-roll mill for milling for 30 minutes, then adding 40 parts of phenolic resin, 15 parts of benzotriazole and 50 parts of zinc borate, mixing them evenly, setting the temperature to 120° C., to obtain a rubber compound;

[0090] S4, using a twin-screw extruder to extrude the rubber mixture obtained in step S3, setting the temperature of the twin-screw extruder to 90° C. and the speed to 200 rpm, cooling at room temperature, and drying to obtain a rubber-modified soft plastic.

[0091] The only difference between Comparative Example 1 and Example 1 is that the addition of natural rubber is omitted, and the rest is the same as Example 1.

[0092] The only difference between Comparative Example 2 and Example 1 is that the addition of butyl rubber is omitted, and the rest is the same as Example 1.

[0093] The only difference between Comparative Example 3 and Example 1 is that the addition of the composite filler is omitted, and the rest is the same as Example 1.

[0094] The difference between Comparative Example 4 and Example 1 is that the preparation method of the composite filler is as follows: HPMC is added to deionized water, the concentration of the HPMC solution is controlled at 2-5 wt%, and the mixture is stirred at 500 rpm in a water bath at 50-60 ° C until the HPMC is completely dissolved to form a uniform HPMC solution; BaCl2·5H2O and Nb2O5 are mixed to form a mixed solution, and then the mixed solution is placed in an autoclave and reacted at 200 ° C for 24 h to obtain a product, which is neutralized with dilute hydrochloric acid (pH = 1). Then, the product is alternately rinsed with deionized water and ethanol three times, and dried in an oven at 70 ° C to obtain BaNbO3 powder; BaNbO3 powder is added to the HPMC solution, placed in an ultrasonic cleaning machine, and mixed at 240 W for 1-3 h to ensure uniform dispersion to form a mixture A; curcumin is added to the mixture A, and stirred at 800 rpm to ensure uniform dispersion to form a mixture B; and the mixture B is placed in a 90 The mixture was reacted in a water bath at ℃ for 4 h, and then taken out and dried to obtain a composite filler.

[0095] Experimental example

[0096] Tensile properties test: According to GB / T528-2009, a TCS-2000 computer system tensile testing machine of China High Speed ​​Rail Testing Instrument Co., Ltd. was used for the test at a tensile speed of 5 mm / min. The rubber-modified soft plastics prepared in Examples 1-4 and Comparative Examples 1-4 were used. The initial samples were cut in the middle and then naturally spliced ​​to prepare test samples. After repairing at 30°C for 20 minutes, the tensile test was performed. The tensile strength was calculated three times, and the average tensile strength was recorded. The calculation results are recorded in Table 1.

[0097] Shore A Hardness Test: Hardness testing was conducted in accordance with GB / T 2411-2008. Samples were prepared using the rubber-modified soft plastics prepared in Examples 1-4 and Comparative Examples 1-4. The samples were placed on a hard, solid horizontal surface. The durometer was held in a vertical position with the tip of the indenter 10 mm from any edge of the sample. The indenter was immediately placed on the sample without impact, parallel to the sample and applying sufficient pressure to ensure close contact between the indenter and the sample. After 15 seconds, the reading on the indicator was read. Five hardness values ​​were measured on the same sample at intervals of 6 mm, and the average value was calculated. The calculated average hardness value is recorded in Table 1.

[0098] Aging resistance test: The rubber-modified soft plastics prepared in Examples 1-4 and Comparative Examples 1-4 were used to make 2 mm dumbbell-shaped specimens on a sheet punching machine. After aging at 70°C in an oven for 72 h, the performance was measured and the average value was taken as P1. Another group was directly tested and the average value P0 was taken. The formula for the heat aging performance retention rate is: P=P1 / P0×100%, where P0 is the performance of the specimen before heat aging, P1 is the performance of the specimen after heat aging, and P is the heat aging performance retention rate of the specimen (%). The calculated heat aging performance retention rate results are recorded in Table 1.

[0099] Antibacterial performance test: The antibacterial test was conducted by the film-sticking method. Smooth and flat test specimens were prepared using the rubber-modified soft plastics prepared in Examples 1-4 and Comparative Examples 1-4. The size of the test specimens was 50 mm × 50 mm × 5 mm (length × width × thickness). The test strain was Escherichia coli (SHBCCD80636) ordered from the Shanghai Collection Biotechnology Center. The Escherichia coli was resuscitated and cultured for 24 h. An appropriate amount of Escherichia coli was selected and placed in sterile physiological saline for mixing and dilution to form a bacterial suspension. All test specimens were disinfected, cleaned, and dried for later use. A single test specimen was placed in a sterile culture dish. The bacterial suspension was aspirated using a dropper. 0.05 ml of the bacterial suspension was dripped onto the surface of the test specimen. The specimen was placed in a culture dish to receive the bacterial suspension. The culture dish cover was then closed and the sample was placed in a constant temperature incubator for 24 h. h; Use equal amounts of eluent to elute the colonies in each test specimen and control specimen, count the number of viable bacteria in the eluent and calculate the antibacterial rate in accordance with the Technical Specifications for Disinfection. The calculation results for each test specimen are shown in Table 1.

[0100] Impact strength test: The impact strength test was conducted according to GB / T 1843-2008. 80 mm × 10 mm × 4 mm test specimens were made from the rubber-modified soft plastics prepared in Examples 1-4 and Comparative Examples 1-4. The impact strength was tested using a cantilever beam test. The pendulum was lifted and locked. When measuring a notched specimen, the notch was on the side where the pendulum struck the specimen. The pendulum was released and the impact energy absorbed by the specimen was recorded. For unnotched specimens, the impact strength was calculated according to the following formula: iN =(E C / h×b N ) × 10 3 , where E c is the corrected sample fracture absorption energy in joules (J), h is the sample thickness in millimeters (mm), b N is the remaining width of the specimen, in millimeters (mm). The average value of the test results is recorded in Table 1.

[0101] Table 1

[0102]

[0103] The results in Table 1 show that the tensile strength, Shore hardness, aging resistance, antibacterial properties, and impact strength of Examples 1-4 are significantly higher than those of Comparative Examples 1-4, indicating that the properties of the rubber-modified soft plastic prepared by the present invention are significantly improved. The interaction between the materials gives the rubber-modified soft plastic excellent properties. Figure 1 This is a schematic diagram of the rubber-modified soft plastic prepared by the present invention. From the enlarged view, it can be seen that the modified HPMC is cross-linked with the BaNbO3 molecular chain, tightly wrapping the BaNbO3, making the dispersion more uniform and the bonding more firm; Figure 2 The limiting oxygen index of the rubber-modified soft plastic prepared by the present invention is shown. The limiting oxygen index is much higher than the self-extinguishing requirement of 27%, indicating that the rubber-modified soft plastic prepared by the present invention has good flame retardant properties. Figure 3 It is shown that the aging resistance of comparative examples 1-4 is significantly lower than that of examples 1-4, and when butyl rubber is not added, the aging resistance is poor, indicating that the interaction between butyl rubber and other materials significantly improves the aging resistance of soft plastics.

[0104] In summary, by introducing natural rubber and butyl rubber into the soft plastic polypropylene, the wear resistance and impact resistance of the material are significantly improved. The combination of modified HPMC and BaNbO3 powder in the composite filler improves the brittleness of BaNbO3, so that the composite filler has better toughness while maintaining high strength. At the same time, it interacts with groups such as hydroxyl groups in HPMC to form a stronger interface bond between BaNbO3 and HPMC, enhancing the mechanical properties of the material and giving it antibacterial properties; the cross-linking agent promotes the cross-linking of various materials, so that materials with different polarities can be more firmly combined with each other, and the solubilizer also improves the oil resistance of the material. Through the interaction between the various materials, the rubber-modified soft plastic prepared by the present invention has good mechanical properties, antibacterial properties, aging resistance and flame retardancy, and can be widely used in the fields of automobiles, construction, electronics, medical care, sports equipment and consumer goods.

[0105] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A rubber-modified soft plastic, characterized in that: The invention is prepared from the following raw materials in parts by weight: 60-90 parts of polypropylene, 10-40 parts of natural rubber, 5-20 parts of butyl rubber, 10-30 parts of composite filler, 1-10 parts of cross-linking agent, 3-15 parts of compatibilizer, 25-40 parts of plasticizer, 4-15 parts of ultraviolet light absorber, and 20-50 parts of flame retardant. The raw materials for preparing the composite filler are: HPMC, BaCl2·5H2O, Nb2O5, curcumin and SMA; the mass ratio of HPMC, BaCl2·5H2O, Nb2O5 and curcumin is 20-30:220:100:1; The preparation method of the composite filler specifically comprises the following steps: (1) HPMC was added to deionized water and stirred in a water bath to form a uniform HPMC solution. SMA was added to the HPMC solution and stirred to obtain a mixed solution. The mixed solution was then subjected to a solvent thermal reaction, washed, and dried to obtain modified HPMC. (2) Weighing a composite base, mixing the composite base with BaCl2·5H2O and Nb2O5, and then performing a solvothermal reaction to obtain a product, neutralizing the product, and then washing and drying to obtain BaNbO3 powder; (3) adding the modified HPMC to deionized water to obtain a modified HPMC solution, adding the BaNbO3 powder to the modified HPMC solution, and mixing them evenly to form a mixture A; (4) adding curcumin to the mixture A obtained in step (3), stirring and mixing to form a mixture B; (5) Adding photoinitiator 1173 to the mixture B obtained in step (4) to carry out a photopolymerization reaction to obtain a HPMC / BaNbO3 precursor, curing the HPMC / BaNbO3 precursor, and then immersing it in deionized water, and then drying it to obtain a composite filler.

2. The rubber-modified soft plastic according to claim 1, characterized in that: The cross-linking agent is hydrogen-containing silicone oil or JT-509 dealcohol-type cross-linking agent.

3. The rubber-modified soft plastic according to claim 1, characterized in that: The compatibilizer is one or more of KH-550, TEOS, and EVA.

4. The rubber-modified soft plastic according to claim 1, characterized in that: The plasticizer is epoxy soybean oil or phenolic resin, the ultraviolet light absorber is benzotriazole, and the flame retardant is zinc borate.

5. The rubber-modified soft plastic according to claim 1, characterized in that: In step (1), the concentration of the HPMC solution is 2-5 wt%, and the mass ratio of the SMA to HPMC solution is 1-5:

100.

6. The rubber-modified soft plastic according to claim 1, characterized in that: In step (2), the mass ratio of the composite alkali to BaCl2·5H2O is 15:1, the temperature of the solvent thermal reaction is set to 200°C, and the time is set to 24 h.

7. The rubber-modified soft plastic according to claim 1, characterized in that: In step (3), the concentration of the modified HPMC solution is 3-8 wt %. In step (5), the mass ratio of the mixture B to the photoinitiator 1173 is 1:0.01-0.03, and the photopolymerization reaction is carried out under ultraviolet light of 365 nm for 1 h.

8. A method for preparing the rubber-modified soft plastic according to any one of claims 1 to 7, characterized in that: The specific steps include: S1, weighing polypropylene, natural rubber, butyl rubber and a compatibilizer in parts by weight and mixing them to obtain a blend; S2, adding a crosslinking agent by weight to the blend obtained in step S1, mixing, then adding a composite filler, mixing for a second time, and mixing to obtain a mixed masterbatch; S3, refining the mixed masterbatch obtained in step S2, adding a plasticizer, an ultraviolet light absorber, and a flame retardant according to parts by weight, and mixing to obtain a rubber compound; S4, extruding the rubber mixture obtained in step S3, cooling, and drying to obtain a rubber-modified soft plastic.

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