Aging-resistant polypropylene particles for outdoor planting pot production and a preparation method thereof

Abstract

The application relates to an anti-aging polypropylene particle for outdoor planting pot production and a preparation method thereof, and belongs to the technical field of high polymer materials. The formula of the anti-aging polypropylene particle is as follows: 80-90 parts of polypropylene, 3-5 parts of a composite anti-aging agent, 1-2 parts of a stabilizer, 4-6 parts of a toughening agent, 1-2 parts of a silane coupling agent and 0.5-0.8 parts of a lubricant. The composite anti-aging agent is constructed through a three-step process, first, lignin is alkaline-activated to form a phenolic oxygen anion active site, second, bis(3-aminopropyl)phenyl phosphine is covalently combined to construct a free radical capture network, and then tetraethyl orthosilicate is in-situ hydrolyzed to form a silica dioxide physical barrier on the surface. The polypropylene particle prepared by the application has good anti-aging performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and relates to a kind of outdoor planting pot production is used to the anti-aging polypropylene particle and its preparation method. BACKGROUND

[0002] Polypropylene (PP) material is widely used in the production of outdoor planting pots due to its low cost, good processing performance, and non-toxicity. However, traditional polypropylene materials are prone to molecular chain rupture when exposed to ultraviolet light, high temperature, and high humidity for a long time in complex outdoor environments, leading to brittleness, discoloration, and strength reduction, significantly shortening the service life. Although some anti-aging polypropylene materials exist in the prior art, they mostly have single function, high addition amount, and insufficient long-term effectiveness, which cannot meet the stringent requirements of outdoor planting pots for comprehensive material performance.

[0003] The existing anti-aging technologies on the market have the following limitations: first, ordinary antioxidants and ultraviolet absorbers gradually lose effectiveness during long-term use, failing to provide long-lasting protection; second, high addition amounts of inorganic fillers can improve weather resistance but severely damage the processing flowability and impact toughness of the material; third, single modification methods cannot resist the synergistic effects of multiple aging factors such as ultraviolet light, thermal oxidation, and microbial erosion. For example, conventional anti-aging polypropylene will show obvious brittleness and cracking after 1-2 years of outdoor use, leading to sudden breakage of the planting pots and causing losses to users.

[0004] Therefore, there is an urgent need to develop a kind of outdoor planting pot production is used to the anti-aging polypropylene particle and its preparation method. SUMMARY

[0005] The purpose of the present application is to provide a kind of outdoor planting pot production is used to the anti-aging polypropylene particle and its preparation method, with good anti-aging performance.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A kind of outdoor planting pot production is used to the anti-aging polypropylene particle, the formula of the anti-aging polypropylene particle is as follows, by weight, polypropylene 80-90 parts, composite anti-aging agent 3-5 parts, stabilizer 1-2 parts, toughening agent 4-6 parts, silane coupling agent 1-2 parts, lubricant 0.5-0.8 parts;

[0008] The preparation method of the composite anti-aging agent is as follows,

[0009] S1-1: add lignin to a NaOH solution with a concentration of 1 mol / L so that the solid-liquid mass ratio is 1:(20-30), ultrasonic treatment for 1-2 h, wash with deionized water and dry to obtain pretreated lignin;

[0010] S1-2: The pretreated lignin and bis(3-aminopropyl)phenyl phosphine are mixed and added to N-methyl pyrrolidone, then pyridine is added, stirring under nitrogen protection for 4-5 h, temperature control at 80-90 ℃, washed with ethanol and deionized water, and vacuum dried at 80 ℃ for 12 h to obtain modified lignin;

[0011] S1-3: The modified lignin is added to ethanol with a mass fraction of 30-40% to make the solid-liquid mass ratio 1:(20-30), tetraethyl orthosilicate is added, ultrasonic dispersion is performed for 30-60 min, 1 M hydrochloric acid is added dropwise until the pH is 4.5-5.5, reaction is performed at 60-80 ℃ for 4-6 h, then aging is performed for 10-12 h, washed with deionized water, and freeze-dried at -40--50 ℃ for 20-24 h to obtain the composite anti-aging agent.

[0012] As a preferred technical solution of the present application, the toughening agent is one or both of ethylene-octene copolymer and styrene-butadiene-styrene block copolymer.

[0013] As a preferred technical solution of the present application, the stabilizer is one or both of UV-531 and UV-326.

[0014] As a preferred technical solution of the present application, the lubricant is zinc stearate.

[0015] As a preferred technical solution of the present application, the mass ratio of pretreated lignin to bis(3-aminopropyl)phenyl phosphine in S1-2 is (3-4):1.

[0016] As a preferred technical solution of the present application, the amount of pyridine used in S1-2 is 5-8% of the mass of lignin.

[0017] As a preferred technical solution of the present application, the amount of tetraethyl orthosilicate added in S1-3 is 5-10% of the mass of modified lignin.

[0018] A preparation method of an anti-aging polypropylene particle for outdoor planting pot production, the specific steps of the preparation method are as follows,

[0019] S8-1: Polypropylene, composite anti-aging agent, stabilizer, toughening agent, silane coupling agent and lubricant are added to a high-speed mixer and mixed for 5-10 min to obtain a premix;

[0020] S8-2: The premix is added to a twin-screw extruder for melt dispersion, the screw rotation speed is 200-300 rpm, the feeding speed is 10-15 kg / h, and extrusion granulation is performed to obtain the anti-aging polypropylene particle.

[0021] As a preferred technical solution of the present application, the premixing speed in S8-1 is 500-600 rpm.

[0022] As a preferred technical solution of the present application, the processing temperature of each zone in the double-screw extruder in S8-2 is 180-190 DEG C for the first zone, 200-210 DEG C for the second zone, 210-220 DEG C for the third zone, 205-215 DEG C for the fourth zone, and 195-205 DEG C for the fifth zone.

[0023] Lignin pretreatment promotes phenolic hydroxyl deprotonation in an alkaline environment to form phenolic oxygen anion active sites, significantly improving surface reactivity. N-methyl pyrrolidone, a polar aprotic solvent, has good solubility for both lignin and bis(3-aminopropyl)phenyl phosphine, and has a high boiling point. The solvent polarity matches the reaction requirements and avoids phase separation. Pyridine as a basic catalyst forms hydrogen bonds with phenolic oxygen anions, reducing the activation energy of dehydrogenation condensation and promoting the covalent bonding of phosphine groups with lignin. The reaction temperature is set higher than the glass transition temperature of lignin to enhance the molecular chain segment movement ability and improve the reaction efficiency; nitrogen protection inhibits the oxidative degradation of lignin and ensures the reaction selectivity.

[0024] Bis(3-aminopropyl)phenyl phosphine can efficiently capture hydroxyl radicals generated during polypropylene degradation through electron transfer of phosphine groups, blocking photooxidation chain reactions. Lignin's inherent conjugated carbonyl and aromatic structure can absorb ultraviolet light of 280-400 nm, reducing polypropylene main chain breakage. The two form a free radical capture-ultraviolet shielding dual functional system through covalent bonding, and the anti-aging performance is significantly improved compared to single components. After combination, the lignin particle size decreases and forms a uniform network structure in the polypropylene matrix, the interfacial interaction strength is improved, effectively transferring stress and inhibiting crack propagation. In addition, the rigid filler effect of lignin can refine the size of polypropylene spherocrystals, simultaneously improving the tensile strength and flexural modulus, while the polar groups of amino and phosphine groups do not significantly sacrifice the impact strength, achieving a balance of rigidity and toughness. Lignin is derived from plant fibers, renewable and low cost, replacing part of the petroleum-based anti-aging agent; lignin can refine polypropylene grains, improve tensile strength and flexural modulus; the introduction of amino and phosphine groups does not significantly reduce the impact strength of polypropylene, balancing rigidity and toughness.

[0025] The hydrolysis of tetraethyl orthosilicate on the surface of modified lignin forms silica, which can act as a physical barrier to block the penetration of ultraviolet light, oxygen and heat, delaying the aging of polypropylene. The composite structure significantly improves the anti-aging performance through the synergistic effect of the light stability of lignin and the thermal stability of silica.

[0026] The beneficial effects of the present application are:

[0027] The present application deprotonates the phenolic hydroxyl group of lignin by alkaline environment to form high-activity phenolate; in N-methyl pyrrolidone, pyridine catalyzes to reduce the phosphine group reaction energy barrier, and a covalently bonded free radical capture network is constructed; the lignin conjugated structure absorbs ultraviolet rays, and cooperates with the in-situ generated silicon dioxide on the surface to block the full-band light aging, while the thermal stability is improved; the composite can refine the polypropylene spherulites, improve the tensile strength and bending modulus, while the amino-phosphine flexible chain maintains the impact strength, realizes the rigid-flexible balance; the renewable lignin replaces the petroleum-based anti-aging agent, and has remarkable environmental protection and economy. DETAILED DESCRIPTION

[0028] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined object, the specific embodiments, structures, features and effects according to the present application are described in detail below in combination with examples.

[0029] In the examples and comparative examples of the present application:

[0030] Polypropylene: purchased from Beijing Huaweiruke Chemical Technology Co., Ltd., melt index 12;

[0031] Lignin: purchased from Wuhan Xinxinjiali Biological Technology Co., Ltd.;

[0032] Bis(3-aminopropyl)phenylphosphine: purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.;

[0033] Pyridine: purchased from Shandong Minghua New Material Co., Ltd.;

[0034] N-methyl pyrrolidone: purchased from Jiangsu Lunfeng Synthetic Technology Co., Ltd.;

[0035] Tetraethyl orthosilicate: purchased from Shanghai Zhuoai Chemical Co., Ltd.;

[0036] Zinc stearate: purchased from Shandong Huishengtang Biological Medicine Co., Ltd.;

[0037] Ethylene-octene copolymer POE: purchased from Hangzhou Jieheng Chemical Co., Ltd.;

[0038] Styrene-butadiene-styrene block copolymer SBS: purchased from Shanghai Baite Chemical Co., Ltd.;

[0039] UV-531: purchased from Fujian Diseng Technology Co., Ltd.;

[0040] UV-326: purchased from Tianjin Li'anlong New Material Co., Ltd.;

[0041] Silane coupling agent KH550: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0042] Example 1

[0043] An anti-aging polypropylene particle for outdoor planting pot production, the formula of the anti-aging polypropylene particle is as follows, polypropylene 85 parts, composite anti-aging agent 4 parts, UV-531 1.5 parts, ethylene-octene copolymer POE 5 parts, silane coupling agent KH550 1.5 parts, zinc stearate 0.6 parts,

[0044] The preparation method of the composite anti-aging agent is as follows,

[0045] S1-1: Lignin is added to a NaOH solution with a concentration of 1 mol / L so that the solid-liquid mass ratio is 1:25, ultrasonic treatment is performed for 1.5 h, deionized water is used for washing and drying, and pretreated lignin is obtained;

[0046] S1-2: The pretreated lignin and bis(3-aminopropyl)phenyl phosphine are mixed according to a mass ratio of 3.5:1 and added to N-methyl pyrrolidone, then pyridine with a mass fraction of 6% of the lignin is added, stirring is performed under nitrogen protection for 4.5 h, the temperature is controlled at 85 ℃, ethanol and deionized water are used for washing, and vacuum drying is performed at 80 ℃ for 12 h, and the modified lignin is obtained;

[0047] S1-3: The modified lignin is added to ethanol with a mass fraction of 35% so that the solid-liquid mass ratio is 1:25, tetraethyl orthosilicate with a mass fraction of 7% of the modified lignin is added, ultrasonic dispersion is performed for 45 min, hydrochloric acid with a concentration of 1 M is added dropwise until the pH is 5, reaction is performed at 70 ℃ for 5 h, then aging is performed for 11 h, deionized water is used for washing, and freeze-drying is performed at -45 ℃ for 22 h, and the composite anti-aging agent is obtained.

[0048] A preparation method of an anti-aging polypropylene particle for outdoor planting pot production, the specific steps of the preparation method are as follows,

[0049] S8-1: Polypropylene, a composite anti-aging agent, a stabilizer, a toughening agent, a silane coupling agent, and a lubricant are added to a high-speed mixer and mixed for 7 min, the premixing speed is 550 rpm, and a premix is obtained;

[0050] S8-2: The premix is added to a twin-screw extruder for melt dispersion, the processing temperatures of the zones in the twin-screw extruder are 185 ℃ for zone one, 205 ℃ for zone two, 215 ℃ for zone three, 210 ℃ for zone four, and 200 ℃ for zone five, the screw rotation speed is 250 rpm, the feeding speed is 12 kg / h, and extrusion granulation is performed, and the anti-aging polypropylene particle is obtained.

[0051] Example 2

[0052] An outdoor planting pot production use anti-aging polypropylene particles, the anti-aging polypropylene particles formula as follows, by weight, polypropylene 80 parts, composite anti-aging agent 3 parts, UV-326 1 part, styrene-butadiene-styrene block copolymer SBS 4 parts, silane coupling agent KH550 1 part, zinc stearate 0.5 parts,

[0053] The preparation method of the composite anti-aging agent is as follows,

[0054] S1-1: lignin is added to a NaOH solution with a concentration of 1 mol / L so that the solid-liquid mass ratio is 1:20, ultrasonic treatment is performed for 1 h, deionized water is used for washing and drying, and pretreated lignin is obtained;

[0055] S1-2: the pretreated lignin and bis(3-aminopropyl)phenyl phosphine are mixed according to a mass ratio of 3:1 and added to N-methyl pyrrolidone, then pyridine with a mass of 5% of the lignin is added, stirring is performed under nitrogen protection for 4 h, the temperature is controlled at 80 DEG C, ethanol and deionized water are used for washing, and vacuum drying is performed at 80 DEG C for 12 h, and the modified lignin is obtained;

[0056] S1-3: the modified lignin is added to ethanol with a mass fraction of 30% so that the solid-liquid mass ratio is 1:20, tetraethyl orthosilicate with a mass of 5% of the modified lignin is added, ultrasonic dispersion is performed for 30 min, hydrochloric acid with a concentration of 1 M is added dropwise until the pH is 4.5, reaction is performed at 60 DEG C for 4 h, then aging is performed for 10 h, deionized water is used for washing, and freeze drying is performed at -40 DEG C for 20 h, and the composite anti-aging agent is obtained.

[0057] A preparation method of an outdoor planting pot production use anti-aging polypropylene particle, the specific steps of the preparation method are as follows,

[0058] S8-1: polypropylene, composite anti-aging agent, stabilizer, toughening agent, silane coupling agent and lubricant are added to a high-speed mixer and mixed for 5 min, the premixing speed is 500 rpm, and a premix is obtained;

[0059] S8-2: the premix is added to a twin-screw extruder for melt dispersion, the processing temperatures of the zones in the twin-screw extruder are 180 DEG C for zone one, 200 DEG C for zone two, 210 DEG C for zone three, 205 DEG C for zone four and 195 DEG C for zone five, the screw rotation speed is 200 rpm, the feeding speed is 10 kg / h, and extrusion granulation is performed, and the anti-aging polypropylene particles are obtained.

[0060] Example 3

[0061] The application discloses an anti-aging polypropylene particle for outdoor planting pot production, and a preparation method of the anti-aging polypropylene particle.

[0062] The preparation method of the composite anti-aging agent is as follows,

[0063] S1-1: lignin is added into a NaOH solution with a concentration of 1 mol / L, so that the solid-liquid mass ratio is 1:30, ultrasonic treatment is carried out for 2 h, and then the pretreated lignin is obtained by washing with deionized water and drying;

[0064] S1-2: the pretreated lignin and bis(3-aminopropyl)phenyl phosphine are mixed according to a mass ratio of 4:1 and then added into N-methylpyrrolidone, pyridine with a mass of 8% of the lignin is added, stirring is carried out under nitrogen protection for 5 h, the temperature is controlled at 90 DEG C, washing is carried out with ethanol and deionized water, and then vacuum drying is carried out at 80 DEG C for 12 h, so that the modified lignin is obtained;

[0065] S1-3: the modified lignin is added into ethanol with a mass fraction of 40%, so that the solid-liquid mass ratio is 1:30, tetraethyl orthosilicate with a mass of 10% of the modified lignin is added, ultrasonic dispersion is carried out for 60 min, hydrochloric acid with a concentration of 1 M is added dropwise until the pH is 5.5, reaction is carried out at 80 DEG C for 6 h, and then aging is carried out for 12 h, washing is carried out with deionized water, and then freezing drying is carried out at-50 DEG C for 24 h, so that the composite anti-aging agent is obtained.

[0066] The application discloses an anti-aging polypropylene particle for outdoor planting pot production, and a preparation method of the anti-aging polypropylene particle.

[0067] S8-1: polypropylene, a composite anti-aging agent, a stabilizer, a toughening agent, a silane coupling agent and a lubricant are added into a high-speed mixer and mixed for 10 min, a premixing speed is 600 rpm, and a premixing material is obtained;

[0068] S8-2: the premixing material is added into a double-screw extruder for melt dispersion, the processing temperature of each zone in the double-screw extruder is 190 DEG C for zone one, 210 DEG C for zone two, 220 DEG C for zone three, 215 DEG C for zone four and 205 DEG C for zone five, the screw rotating speed is 300 rpm, the feeding speed is 15 kg / h, and extrusion granulation is carried out, so that the anti-aging polypropylene particle is obtained.

[0069] Comparative example 1

[0070] In the preparation of the composite anti-aging agent, the lignin is not pretreated, and the remaining steps are consistent with those of example 1.

[0071] Comparative Example 2

[0072] The preparation of the composite anti-aging agent does not add bis(3- aminopropyl) phenyl phosphine, and the remaining steps are consistent with Example 1.

[0073] Comparative Example 3

[0074] The preparation of the composite anti-aging agent does not add tetraethyl orthosilicate, and the remaining steps are consistent with Example 1.

[0075] Comparative Example 4

[0076] The preparation of the composite anti-aging agent does not go through the S1-2 step, and the remaining steps are consistent with Example 1.

[0077] Comparative Example 5

[0078] The remaining steps are consistent with Example 1 without adding a composite anti-aging agent.

[0079] Performance test

[0080] The modified polypropylene particles obtained by the examples and comparative examples were made into 80x10x4mm samples, which were aged at 65℃ and a wavelength of 340nm light for 1000h, and the tensile strength, flexural modulus and Izod notched impact strength of the material before and after aging were measured respectively.

[0081] The tensile strength was measured according to the test standard ISO 527-2-2012, and the tensile speed was 50mm / min. The flexural modulus was measured according to the test standard ISO 178-2010, and the bending speed was 2mm / min, and the span was 64mm. The Izod notched impact strength was measured according to the test standard ISO 180.

[0082] The performance change rate%=(pre-aging performance-post-aging performance) / pre-aging performancex100%

[0083] The experimental results are arranged in the following table.

[0084] Group Change rate of tensile strength before and after aging (%) Change rate of flexural modulus before and after aging (%) Change rate of Izod notched impact strength before and after aging (%) Example 1 5.6 6.2 8.5 Example 2 6.1 7.7 8.9 Example 3 5.9 7.3 8.5 Comparative Example 1 18.6 19.4 25.4 Comparative Example 2 23.1 23.8 30.1 Comparative Example 3 19.3 20.5 27.3 Comparative Example 4 28.5 29.1 34.8 Comparative Example 5 32.0 33.7 39.7

[0085] From the data of the examples and comparative examples, it can be seen that the polypropylene material prepared by the method of the present application has good aging resistance.

[0086] The above merely describes the preferred embodiments of the present application, and is not intended to limit the present application in any form. Although the present application has been disclosed with the preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content to obtain equivalent embodiments with equivalent changes, as long as the changes or modifications do not deviate from the technical solution of the present application. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. An outdoor planting pot production use anti-aging polypropylene particle, characterized by, The formula of the anti-aging polypropylene particles is as follows: polypropylene 80-90 parts, composite anti-aging agent 3-5 parts, stabilizer 1-2 parts, toughening agent 4-6 parts, silane coupling agent 1-2 parts, and lubricant 0.5-0.8 parts by weight; The preparation method of the composite anti-aging agent is as follows, S1-1: lignin is added to a NaOH solution with a concentration of 1 mol / L so that the solid-liquid mass ratio is 1:(20-30), ultrasonic treatment is performed for 1-2 h, deionized water is used for washing and drying, and pretreated lignin is obtained; S1-2: the pretreated lignin and bis(3-aminopropyl)phenyl phosphine are mixed and added to N-methyl pyrrolidone, pyridine is then added, stirring is performed under nitrogen protection for 4-5 h, the temperature is controlled at 80-90 ℃, ethanol and deionized water are used for washing, and vacuum drying is performed at 80 ℃ for 12 h, and modified lignin is obtained; S1-3: the modified lignin is added to ethanol with a mass fraction of 30-40% so that the solid-liquid mass ratio is 1:(20-30), tetraethyl orthosilicate is added, ultrasonic dispersion is performed for 30-60 min, 1 M hydrochloric acid is added dropwise until the pH is 4.5-5.5, reaction is performed at 60-80 ℃ for 4-6 h, aging is then performed for 10-12 h, deionized water is used for washing, and freeze-drying is performed at -40--50 ℃ for 20-24 h, and the composite anti-aging agent is obtained; The mass ratio of the pretreated lignin to bis(3-aminopropyl)phenyl phosphine in S1-2 is (3-4):1; The amount of pyridine used in S1-2 is 5-8% of the mass of the lignin; The amount of tetraethyl orthosilicate added in S1-3 is 5-10% of the mass of the modified lignin.

2. The weatherable polypropylene resin particles for producing an outdoor planting pot according to claim 1, characterized by, The toughening agent is one or both of ethylene-octene copolymer and styrene-butadiene-styrene block copolymer.

3. The outdoor planting pot production of the anti-aging polypropylene particles according to claim 1, characterized in that, The stabilizer is one or both of UV-531 and UV-326.

4. The outdoor planting pot production of the anti-aging polypropylene particles according to claim 1, characterized in that, The lubricant is zinc stearate.

5. A method for producing the weatherable polypropylene particles for outdoor planting pots according to any one of claims 1 to 4, characterized by, The specific steps of the preparation method are as follows, S8-1: polypropylene, composite anti-aging agent, stabilizer, toughening agent, silane coupling agent, and lubricant are added to a high-speed mixer and mixed for 5-10 min to obtain a premix; S8-2: the premix is added to a twin-screw extruder for melt dispersion, the screw rotation speed is 200-300 rpm, the feeding speed is 10-15 kg / h, and extrusion granulation is performed to obtain the anti-aging polypropylene particles.

6. The method of producing the weatherable polypropylene pellets for outdoor planting pots according to claim 5, characterized in that, The premixing speed in S8-1 is 500-600 rpm.

7. The method of producing an anti-aging polypropylene particle for an outdoor planting pot according to claim 5, characterized in that, The processing temperatures of the zones in the twin-screw extruder in S8-2 are 180-190 ℃ for zone 1, 200-210 ℃ for zone 2, 210-220 ℃ for zone 3, 205-215 ℃ for zone 4, and 195-205 ℃ for zone 5, respectively.