A method for producing plastic masterbatch based on online melt mixing and its application

Abstract

This invention relates to the technical field of plastic masterbatch production, and discloses a method for producing plastic masterbatch based on online melt mixing and its application. The production method includes the following steps: (1) a carrier resin is transported in melt form to the main feed port of a twin-screw extruder by a metering pump; (2) an additive is fed into the side feed port of the twin-screw extruder and mixed online with the carrier resin; (3) the mixture is melt-extruded and pelletized to obtain plastic masterbatch. This invention utilizes the online mixing of the resin carrier melt and functional additives to shorten the processing flow, reduce equipment energy consumption, and reduce adverse factors such as powder dispersion, thereby obtaining plastic masterbatch with good functionality.

Description

Technical Field

[0001] This invention relates to the technical field of plastic masterbatch production, and in particular to a method for producing plastic masterbatch based on online melt mixing and its application. Background Technology

[0002] Polymer materials, as an important class of materials, have played a significant role in people's daily lives and various industrial fields. However, with the rapid development of the social economy, the production applications of various industries are gradually placing new demands on the functionality of polymer materials. In actual production, in order to cope with changes in market demand and rapid product iteration, it is necessary to adjust product production lines more flexibly. Masterbatch, as a high-concentration, high-efficiency resin mixture, can be added to the matrix resin at any time to adjust its color, function, etc.

[0003] Traditional plastic masterbatch production processes are demanding, including dry and wet processes. The wet process involves grinding, phase inversion, washing, drying, and granulation of the masterbatch material. For example, Chinese invention patent CN110028708A discloses a method for preparing wet-process zinc oxide pre-dispersion masterbatch, which involves preparing a rubber liquid and a mixed slurry containing functional additives, followed by mixing, flocculation, drying, and granulation to obtain the masterbatch. The dry process utilizes equipment such as high-speed mixers, single / twin screw extruders, and internal mixers to mix resin powder and additive powders to produce high-quality masterbatch. For example, Chinese invention patent CN1488665A discloses a production process for color masterbatch, which involves premixing dispersant and filler, followed by extrusion granulation; Chinese invention patent CN114805979A discloses a preparation process for color masterbatch, which involves pre-treating color powder, dispersant, processing aid and filler by sand milling, mixing with carrier in a high-speed mixer, performing melt blending using a twin-screw extruder, and then extruding and granulating to obtain the desired masterbatch.

[0004] The aforementioned masterbatch production processes and methods still have certain defects and shortcomings, namely, complex process flows, high energy consumption, and powder pollution during production, which is detrimental to the production environment and operators. Therefore, proposing a masterbatch production process that further simplifies the production flow, controls production costs, and optimizes the production environment is of great significance. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for producing plastic masterbatch based on online melt mixing and its application. By utilizing the online mixing of the resin carrier melt and functional additives, the processing flow is shortened, equipment energy consumption is reduced, and adverse factors such as powder dispersion are minimized, thereby obtaining plastic masterbatch with good functionality.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] In a first aspect, the present invention provides a method for producing plastic masterbatch based on online melt mixing, comprising the following steps:

[0008] (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump;

[0009] (2) The additive is fed into the side feed port of the twin screw and mixed online with the carrier resin;

[0010] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0011] In this invention, the carrier resin melt is metered and conveyed after melting corresponding chips, or directly metered and conveyed by the corresponding resin polymerization device. It is then dispersed, mixed, and extruded with other additives fed from the twin-screw extruder. Compared to traditional masterbatch processing, this invention eliminates the need to pulverize the carrier resin, saving on the cost of grinding equipment and energy consumption. Furthermore, it eliminates the need for pre-mixing the carrier resin with other additives into powder, reducing dust pollution during masterbatch production, effectively improving the working environment, enhancing operational safety, and benefiting employee health.

[0012] Preferably, the carrier resin is a UV-resistant modified PET resin, and its preparation method includes the following steps:

[0013] (a) Terephthalic acid, ethylene glycol and catalyst are mixed and esterified.

[0014] (b) Add an epichlorohydrin-modified UV absorber to carry out a pre-condensation reaction; the UV absorber is 2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole, 2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone or 2-hydroxy-4-methacrylate-based benzophenone;

[0015] (c) Add oleic acid and tannic acid to carry out a final polycondensation reaction to obtain UV-resistant modified PET resin.

[0016] The UV-resistant modified PET resin of this invention is prepared by introducing a UV absorber into the polyester molecular chain. The UV absorber is responsible for absorbing ultraviolet light and converting it into heat energy, thereby preventing the formation of free radicals. Grafting enhances the UV resistance of the polyester matrix, resulting in higher overall structural stability and compatibility. The UV absorber used contains hydroxyl groups, enabling it to react with epichlorohydrin and be grafted into the polyester molecular chain. Furthermore, the UV absorber also contains double bonds, allowing for the further grafting of tannic acid via oleic acid reaction. Tannic acid is rich in phenolic hydroxyl groups, and the surface of the subsequently added inorganic nanoparticles is also rich in hydroxyl groups, allowing for good adsorption due to π-π interactions and hydrogen bonding, thus improving structural stability. Oleic acid, with its long aliphatic molecular chains, provides local lubrication, improving the dispersion of the inorganic nanoparticles.

[0017] Inorganic nanoparticles primarily reflect and scatter ultraviolet (UV) radiation in the mid-wave and long-wave ranges, effectively creating a barrier between the polyester matrix and the light source. This prevents UV radiation from reaching the polyester interior, providing the first layer of UV protection. UV absorbers then act as a second layer, further reducing the damaging effects of UV radiation on the polyester matrix. Through this multi-layered synergistic mechanism of reflection, scattering, absorption, and elimination, UV radiation exposure during product exposure can be effectively addressed, resulting in polyester masterbatches with outstanding UV protection. Furthermore, modification of the carrier resin helps improve the molecular chain structure, enhances structural stability and compatibility, leading to even better synergistic effects.

[0018] Preferably, in step (a), the molar ratio of terephthalic acid to ethylene glycol is 1:1.1 to 1.7; the esterification reaction is carried out under a nitrogen atmosphere at 200 to 220°C under normal pressure for 20 to 50 minutes, and under pressure at 220 to 250°C and 0.2 to 0.4 MPa for 120 to 180 minutes, and the reaction is stopped when the amount of water produced reaches 90% of the theoretical amount of water produced.

[0019] Preferably, in step (b), the preparation method of the epichlorohydrin-modified ultraviolet absorber includes the following steps: adding an ultraviolet absorber and epichlorohydrin in a molar ratio of 1:2 to 3 to dimethyl sulfoxide and mixing them, and carrying out a first heating reaction; then adding an aqueous solution of sodium hydroxide, with a molar ratio of sodium hydroxide to ultraviolet absorber of 3 to 4:1, and carrying out a second heating reaction; and then performing post-treatment to obtain the epichlorohydrin-modified ultraviolet absorber.

[0020] Preferably, the first heating reaction is carried out at 60-70°C for 1-2 hours; the second heating reaction is carried out at 80-90°C for 1-2 hours. The post-treatment is as follows: first, water extraction and washing are performed, followed by rotary evaporation, then the precipitate is dissolved in diethyl ether and dried to obtain the epichlorohydrin-modified ultraviolet absorber.

[0021] Preferably, the amount of epichlorohydrin-modified UV absorber added is 1-2% of the mass of the UV-resistant modified PET resin; the mass ratio of the epichlorohydrin-modified UV absorber, oleic acid and tannic acid is 1:1.5-2:5-6.

[0022] The amount of tannic acid added will affect the dispersibility of inorganic nanoparticles, but if too much is added, it will affect subsequent processing and lead to poor spinning effect.

[0023] Preferably, in step (c), the pre-condensation reaction is carried out at 240–250°C and 10–40 Pa for 30–60 min; and the final condensation reaction is carried out at 260–270°C and 70–80 Pa for 60–90 min.

[0024] Preferably, in step (2), the additives include inorganic nanoparticles, light stabilizers, antioxidants and coupling agents; the mass ratio of the carrier resin to the inorganic nanoparticles, light stabilizers, antioxidants and coupling agents is 50-70:15-20:0.01-1.0:0.05-1.0:0.2-2.0.

[0025] Light stabilizers are primarily responsible for scavenging free radicals generated by ultraviolet radiation. Dispersants and coupling agents help to uniformly disperse inorganic powders in the polyester melt. Antioxidants are used to prevent thermal degradation during processing and can also delay aging issues during material service. The combination of carrier resin and inorganic nanoparticles, along with the synergistic effect of various additives, can achieve better UV resistance and anti-aging effects.

[0026] Preferably, the inorganic nanopowder is a mixture of nano-titanium dioxide and nano-zinc oxide in a mass ratio of 2 to 3:1, with the titanium dioxide particle size being 10 to 100 nm and the zinc oxide particle size being 20 to 100 nm.

[0027] Preferably, the light stabilizer is 2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084).

[0028] Preferably, the antioxidant is one or both of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010) and tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168).

[0029] Preferably, the coupling agent is one or more of γ-aminopropyltrimethoxysilane (KH-540), γ-aminopropyltriethoxysilane (KH-550), and N-aminoethyl-γ-aminopropyltrimethoxysilane (KH-792).

[0030] Secondly, the present invention also provides an application of the plastic masterbatch obtained by the above-mentioned production method in spinning.

[0031] As a preferred option, the prepared plastic masterbatch and conventional PET chips are dried, mixed evenly at a mass ratio of 1:15, and then spun at a spinning temperature of 260-285℃, with the draw ratio controlled at 3.5-4.5.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] (1) The process of online melt mixing reduces dust pollution during masterbatch production, effectively improves the working environment, enhances operational safety, and is also beneficial to the health of employees.

[0034] (2) UV-resistant modified PET resin can better resist UV rays on the polyester matrix by introducing UV absorbers into the polyester molecular chain, and improve the stability and compatibility of the overall structure.

[0035] (3) The synergistic effect of UV-resistant modified PET resin and inorganic nanoparticles, through multiple UV-resistant mechanisms of reflection, scattering, absorption and elimination, can better cope with the UV radiation that the product is exposed to, and prepare polyester masterbatch with outstanding UV resistance. Detailed Implementation

[0036] The technical solution of the present invention is illustrated below with specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0037] Example 1

[0038] A method for producing plastic masterbatch based on online melt mixing includes the following steps:

[0039] (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump;

[0040] The carrier resin is a UV-resistant modified PET resin, and its preparation method includes the following steps:

[0041] (a) Terephthalic acid, ethylene glycol and catalyst (tetrabutyl titanate) in a molar ratio of 1:1.5:0.01 were mixed and esterified at 200°C under normal pressure for 30 min under nitrogen atmosphere, and then esterified under pressure at 240°C and 0.3 MPa for 150 min. The reaction was stopped when the amount of water produced reached 90% of the theoretical amount of water produced.

[0042] (b) A mixture of UV absorber (2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone), epichlorohydrin and dimethyl sulfoxide in a molar ratio of 1:2.2:40 was heated at 65°C for 2 hours; then a 20 wt% aqueous solution of sodium hydroxide was added, with a molar ratio of sodium hydroxide to UV absorber of 3:1, and the mixture was reacted at 80°C for 1.5 hours; the mixture was then extracted and washed with water, followed by rotary evaporation, and then the precipitate was dissolved in diethyl ether and dried to obtain an epichlorohydrin-modified UV absorber.

[0043] An epichlorohydrin-modified UV absorber was added to the reaction product in step (1), the amount of which was 1.5% of the mass of the obtained UV-resistant modified PET resin, and a pre-condensation reaction was carried out at 250°C and 20 Pa for 30 min.

[0044] (c) Add oleic acid and tannic acid, wherein the mass ratio of epichlorohydrin-modified UV absorber, oleic acid and tannic acid is 1:1.6:5. Perform final polycondensation reaction at 265℃ and 70Pa for 75min to obtain UV-resistant modified PET resin.

[0045] (2) Inorganic nanoparticles, light stabilizer (2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084)), antioxidant (antioxidant 1010) and coupling agent (KH-540) are fed into the side feed port of the twin screw. The mass ratio of carrier resin to inorganic nanoparticles, light stabilizer, antioxidant and coupling agent is 55:18:0.05:0.05:1.0. The inorganic nanoparticles are a mixture of nano titanium dioxide (average particle size of 50 nm) and nano zinc oxide (average particle size of 50 nm) with a mass ratio of 3:1. The mixture is then mixed with the carrier resin online.

[0046] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0047] Example 2

[0048] A method for producing plastic masterbatch based on online melt mixing includes the following steps:

[0049] (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump;

[0050] The carrier resin is a UV-resistant modified PET resin, and its preparation method includes the following steps:

[0051] (a) Terephthalic acid, ethylene glycol and catalyst (tetrabutyl titanate) in a molar ratio of 1:1.2:0.01 were mixed and esterified at 200°C under normal pressure for 30 min under nitrogen atmosphere, and then esterified under pressure at 230°C and 0.4 MPa for 140 min. The reaction was stopped when the amount of water produced reached 90% of the theoretical amount of water produced.

[0052] (b) A mixture of UV absorber (2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone), epichlorohydrin and dimethyl sulfoxide in a molar ratio of 1:3:40 was heated at 70°C for 1 h; then a 20 wt% aqueous solution of sodium hydroxide was added, with a molar ratio of sodium hydroxide to UV absorber of 3.5:1, and the mixture was reacted at 90°C for 1 h; the mixture was then extracted and washed with water, followed by rotary evaporation, and then the precipitate was dissolved in diethyl ether and dried to obtain an epichlorohydrin-modified UV absorber;

[0053] An epichlorohydrin-modified UV absorber was added to the reaction product in step (1), the amount of which was 2% of the mass of the obtained UV-resistant modified PET resin, and a pre-condensation reaction was carried out at 250°C and 30 Pa for 40 min.

[0054] (c) Add oleic acid and tannic acid, wherein the mass ratio of epichlorohydrin-modified UV absorber, oleic acid and tannic acid is 1:1.6:5. Perform final polycondensation reaction at 270℃ and 80Pa for 70min to obtain UV-resistant modified PET resin.

[0055] (2) Inorganic nanoparticles, light stabilizer (2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084)), antioxidant (antioxidant 1010) and coupling agent (KH-540) are fed into the side feed port of the twin screw. The mass ratio of carrier resin to inorganic nanoparticles, light stabilizer, antioxidant and coupling agent is 55:15:0.05:0.05:1.0. The inorganic nanoparticles are a mixture of nano titanium dioxide (average particle size of 50 nm) and nano zinc oxide (average particle size of 50 nm) with a mass ratio of 3:1. The mixture is then mixed with the carrier resin online.

[0056] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0057] Example 3

[0058] A method for producing plastic masterbatch based on online melt mixing includes the following steps:

[0059] (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump;

[0060] The carrier resin is a UV-resistant modified PET resin, and its preparation method includes the following steps:

[0061] (a) Terephthalic acid, ethylene glycol and catalyst (tetrabutyl titanate) in a molar ratio of 1:1.7:0.01 were mixed and esterified at 220°C under normal pressure for 40 min under nitrogen atmosphere, and then esterified under pressure at 250°C and 0.4 MPa for 160 min. The reaction was stopped when the amount of water produced reached 90% of the theoretical amount of water.

[0062] (b) A mixture of UV absorber (2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone), epichlorohydrin and dimethyl sulfoxide in a molar ratio of 1:2:40 was heated at 60°C for 1 h; then a 20 wt% aqueous solution of sodium hydroxide was added, with a molar ratio of sodium hydroxide to UV absorber of 3:1, and the mixture was reacted at 85°C for 2 h; the mixture was then extracted and washed with water, followed by rotary evaporation, and then the precipitate was dissolved in diethyl ether and dried to obtain an epichlorohydrin-modified UV absorber;

[0063] An epichlorohydrin-modified UV absorber was added to the reaction product in step (1), the amount of which was 1% of the mass of the obtained UV-resistant modified PET resin, and a pre-condensation reaction was carried out at 240℃ and 40Pa for 50 minutes.

[0064] (c) Add oleic acid and tannic acid, wherein the mass ratio of epichlorohydrin-modified UV absorber, oleic acid and tannic acid is 1:2:6. Perform a final polycondensation reaction at 270℃ and 80Pa for 90 minutes to obtain UV-resistant modified PET resin.

[0065] (2) Inorganic nanoparticles, light stabilizer (2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084)), antioxidant (antioxidant 1010) and coupling agent (KH-540) are fed into the side feed port of the twin screw. The mass ratio of carrier resin to inorganic nanoparticles, light stabilizer, antioxidant and coupling agent is 65:20:0.05:0.05:1.0. The inorganic nanoparticles are a mixture of nano titanium dioxide (average particle size of 50 nm) and nano zinc oxide (average particle size of 50 nm) with a mass ratio of 2:1. The mixture is then mixed with the carrier resin online.

[0066] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0067] Comparative Example 1

[0068] The difference from Example 1 is that the carrier resin was not modified.

[0069] A method for producing plastic masterbatch based on online melt mixing includes the following steps:

[0070] (1) The carrier resin is delivered to the twin-screw main feed port in the form of melt by a metering pump; the carrier resin is conventional PET resin.

[0071] (2) Inorganic nanoparticles, light stabilizer (2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084)), antioxidant (antioxidant 1010) and coupling agent (KH-540) are fed into the side feed port of the twin screw. The mass ratio of carrier resin to inorganic nanoparticles, light stabilizer, antioxidant and coupling agent is 55:18:0.05:0.05:1.0. The inorganic nanoparticles are a mixture of nano titanium dioxide (average particle size of 50 nm) and nano zinc oxide (average particle size of 50 nm) with a mass ratio of 3:1. The mixture is then mixed with the carrier resin online.

[0072] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0073] Comparative Example 2

[0074] The difference from Example 1 is that oleic acid and tannic acid were not added.

[0075] A method for producing plastic masterbatch based on online melt mixing includes the following steps:

[0076] (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump;

[0077] The carrier resin is a UV-resistant modified PET resin, and its preparation method includes the following steps:

[0078] (a) Terephthalic acid, ethylene glycol and catalyst (tetrabutyl titanate) in a molar ratio of 1:1.5:0.01 were mixed and esterified at 200°C under normal pressure for 30 min under nitrogen atmosphere, and then esterified under pressure at 240°C and 0.3 MPa for 150 min. The reaction was stopped when the amount of water produced reached 90% of the theoretical amount of water produced.

[0079] (b) A mixture of UV absorber (2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone), epichlorohydrin and dimethyl sulfoxide in a molar ratio of 1:2.2:40 was heated at 65°C for 2 hours; then a 20 wt% aqueous solution of sodium hydroxide was added, with a molar ratio of sodium hydroxide to UV absorber of 3:1, and the mixture was reacted at 80°C for 1.5 hours; the mixture was then extracted and washed with water, followed by rotary evaporation, and then the precipitate was dissolved in diethyl ether and dried to obtain an epichlorohydrin-modified UV absorber.

[0080] An epichlorohydrin-modified UV absorber was added to the reaction product in step (1), and the amount added was 1.5% of the mass of the obtained UV-resistant modified PET resin. The condensation reaction was carried out at 260℃ and 50Pa for 110 min to obtain the UV-resistant modified PET resin.

[0081] (2) Inorganic nanoparticles, light stabilizer (2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084)), antioxidant (antioxidant 1010) and coupling agent (KH-540) are fed into the side feed port of the twin screw. The mass ratio of carrier resin to inorganic nanoparticles, light stabilizer, antioxidant and coupling agent is 55:18:0.05:0.05:1.0. The inorganic nanoparticles are a mixture of nano titanium dioxide (average particle size of 50 nm) and nano zinc oxide (average particle size of 50 nm) with a mass ratio of 3:1. The mixture is then mixed with the carrier resin online.

[0082] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0083] Comparative Example 3

[0084] The difference from Example 1 is that oleic acid was not added.

[0085] A method for producing plastic masterbatch based on online melt mixing includes the following steps:

[0086] (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump;

[0087] The carrier resin is a UV-resistant modified PET resin, and its preparation method includes the following steps:

[0088] (a) Terephthalic acid, ethylene glycol and catalyst (tetrabutyl titanate) in a molar ratio of 1:1.5:0.01 were mixed and esterified at 200°C under normal pressure for 30 min under nitrogen atmosphere, and then esterified under pressure at 240°C and 0.3 MPa for 150 min. The reaction was stopped when the amount of water produced reached 90% of the theoretical amount of water produced.

[0089] (b) A mixture of UV absorber (2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone), epichlorohydrin and dimethyl sulfoxide in a molar ratio of 1:2.2:40 was heated at 65°C for 2 hours; then a 20 wt% aqueous solution of sodium hydroxide was added, with a molar ratio of sodium hydroxide to UV absorber of 3:1, and the mixture was reacted at 80°C for 1.5 hours; the mixture was then extracted and washed with water, followed by rotary evaporation, and then the precipitate was dissolved in diethyl ether and dried to obtain an epichlorohydrin-modified UV absorber.

[0090] An epichlorohydrin-modified UV absorber was added to the reaction product in step (1), the amount of which was 1.5% of the mass of the obtained UV-resistant modified PET resin, and a pre-condensation reaction was carried out at 250°C and 20 Pa for 30 min.

[0091] (c) Add tannic acid, wherein the mass ratio of epichlorohydrin-modified UV absorber to tannic acid is 1:5, and carry out a final polycondensation reaction at 265℃ and 70Pa for 75 minutes to obtain UV-resistant modified PET resin.

[0092] (2) Inorganic nanoparticles, light stabilizer (2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084)), antioxidant (antioxidant 1010) and coupling agent (KH-540) are fed into the side feed port of the twin screw. The mass ratio of carrier resin to inorganic nanoparticles, light stabilizer, antioxidant and coupling agent is 55:18:0.05:0.05:1.0. The inorganic nanoparticles are a mixture of nano titanium dioxide (average particle size of 50 nm) and nano zinc oxide (average particle size of 50 nm) with a mass ratio of 3:1. The mixture is then mixed with the carrier resin online.

[0093] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0094] Comparative Example 4

[0095] The difference from Example 1 is that too much tannic acid was added.

[0096] A method for producing plastic masterbatch based on online melt mixing includes the following steps:

[0097] (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump;

[0098] The carrier resin is a UV-resistant modified PET resin, and its preparation method includes the following steps:

[0099] (a) Terephthalic acid, ethylene glycol and catalyst (tetrabutyl titanate) in a molar ratio of 1:1.5:0.01 were mixed and esterified at 200°C under normal pressure for 30 min under nitrogen atmosphere, and then esterified under pressure at 240°C and 0.3 MPa for 150 min. The reaction was stopped when the amount of water produced reached 90% of the theoretical amount of water produced.

[0100] (b) A mixture of UV absorber (2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone), epichlorohydrin and dimethyl sulfoxide in a molar ratio of 1:2.2:40 was heated at 65°C for 2 hours; then a 20 wt% aqueous solution of sodium hydroxide was added, with a molar ratio of sodium hydroxide to UV absorber of 3:1, and the mixture was reacted at 80°C for 1.5 hours; the mixture was then extracted and washed with water, followed by rotary evaporation, and then the precipitate was dissolved in diethyl ether and dried to obtain an epichlorohydrin-modified UV absorber.

[0101] An epichlorohydrin-modified UV absorber was added to the reaction product in step (1), the amount of which was 1.5% of the mass of the obtained UV-resistant modified PET resin, and a pre-condensation reaction was carried out at 250°C and 20 Pa for 30 min.

[0102] (c) Add oleic acid and tannic acid, wherein the mass ratio of epichlorohydrin-modified UV absorber, oleic acid and tannic acid is 1:1.6:8, and carry out a final polycondensation reaction at 265℃ and 70Pa for 75 minutes to obtain UV-resistant modified PET resin.

[0103] (2) Inorganic nanoparticles, light stabilizer (2,2-thiobis(4-tert-octylphenol) n-butylamine nickel salt (UV-1084)), antioxidant (antioxidant 1010) and coupling agent (KH-540) are fed into the side feed port of the twin screw. The mass ratio of carrier resin to inorganic nanoparticles, light stabilizer, antioxidant and coupling agent is 55:18:0.05:0.05:1.0. The inorganic nanoparticles are a mixture of nano titanium dioxide (average particle size of 50 nm) and nano zinc oxide (average particle size of 50 nm) with a mass ratio of 3:1. The mixture is then mixed with the carrier resin online.

[0104] (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

[0105] The plastic masterbatch prepared in the examples and comparative examples and conventional PET chips were dried at 120°C for 20 hours, then mixed evenly at a mass ratio of 1:15, and spun at a spinning temperature of 275°C with a draw ratio controlled at 4.0 to obtain polyester DTY products. The spun fibers were characterized by ultraviolet protection factor (UPF) according to GB / T 18830-2009 "Evaluation of UV protection performance of textiles". Each sample was tested three times and the average value was taken. The tensile strength and elongation at break were tested according to standard GB / T 1040.2-2022. The test results are shown in Table 1.

[0106] Table 1

[0107] UPF value Tensile strength (cN / dtex) Elongation at break (%) Example 1 54.43 4.19 22.12 Example 2 53.82 4.13 21.76 Example 3 52.37 4.02 22.36 Comparative Example 1 40.38 3.68 18.56 Comparative Example 2 43.56 3.73 19.87 Comparative Example 3 46.78 3.71 20.64 Comparative Example 4 48.93 3.82 19.66

[0108] As shown in Table 1, the present invention, through an online melt mixing process, reduces dust pollution during masterbatch production, effectively improves the working environment, enhances operational safety, and is also beneficial to employee health. Comparative Example 1 shows that the UV-resistant modified PET resin in this invention, by introducing UV absorbers into the polyester molecular chain, can better resist UV radiation on the polyester matrix and synergistically achieve multiple UV-resistant effects with inorganic nanoparticles, while also significantly improving the overall structural stability and compatibility. Comparative Examples 2-4 show that tannic acid can optimize the stability and dispersibility of inorganic nanoparticles, but excessive addition can hinder spinning. Oleic acid, on the other hand, can act as a local lubricant and, in conjunction with tannic acid, improve structural stability while giving the plastic masterbatch good spinnability and mechanical properties.

[0109] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made using the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for producing plastic masterbatch based on online melt mixing, characterized in that, include: A UV absorber and epichlorohydrin in a molar ratio of 1:2~3 were added to dimethyl sulfoxide and mixed, and the mixture was heated for the first reaction. An aqueous solution of sodium hydroxide is added, with a molar ratio of sodium hydroxide to UV absorber of 3-4:

1. The reaction is carried out with a second heating. After post-treatment, an epichlorohydrin-modified UV absorber is obtained. The UV absorber is 2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole, 2-hydroxy-4-(3-methacrylate-2-hydroxypropoxy)benzophenone, or 2-hydroxy-4-methacrylate-based benzophenone. Terephthalic acid, ethylene glycol and catalyst are mixed and esterified; an epichlorohydrin-modified UV absorber is added and pre-polymerization is carried out; oleic acid and tannic acid are added and final polymerization is carried out to obtain the carrier resin. (1) The carrier resin is delivered to the twin-screw main feed inlet in the form of melt by a metering pump; (2) The additive is fed into the side feed port of the twin screw and mixed online with the carrier resin; (3) Plastic masterbatch is obtained by melt extrusion and pelletizing.

2. The method for producing plastic masterbatch based on online melt mixing as described in claim 1, characterized in that, The molar ratio of terephthalic acid to ethylene glycol is 1:1.1~1.7; the esterification reaction is as follows: under a nitrogen atmosphere, esterification is carried out at atmospheric pressure at 200~220 ºC for 20~50 min, and then under pressure at 220~250 ºC and 0.2~0.4 MPa for 120~180 min, and the reaction is stopped when the amount of water produced reaches 90% of the theoretical amount of water produced.

3. The method for producing plastic masterbatch based on online melt mixing as described in claim 1, characterized in that, The first heating reaction is carried out at 60-70 ºC for 1-2 h; the second heating reaction is carried out at 80-90 ºC for 1-2 h.

4. The method for producing plastic masterbatch based on online melt mixing as described in claim 1, characterized in that, The amount of epichlorohydrin-modified UV absorber added is 1-2% of the mass of the UV-resistant modified PET resin; the mass ratio of the epichlorohydrin-modified UV absorber, oleic acid and tannic acid is 1:1.5-2:5-6.

5. The method for producing plastic masterbatch based on online melt mixing as described in claim 1 or 4, characterized in that, The pre-condensation reaction is carried out at 240~250 ºC and 10~40 Pa for 30~60 min; the final condensation reaction is carried out at 260~270 ºC and 70~80 Pa for 60~90 min.

6. The method for producing plastic masterbatch based on online melt mixing as described in claim 1, characterized in that, In step (2), the additives include inorganic nanoparticles, light stabilizers, antioxidants and coupling agents; the mass ratio of the carrier resin to inorganic nanoparticles, light stabilizers, antioxidants and coupling agents is 50~70:15~20:0.01~1.0:0.05~1.0:0.2~2.

0.

7. The method for producing plastic masterbatch based on online melt mixing as described in claim 6, characterized in that, The inorganic nanopowder is a mixture of nano-titanium dioxide and nano-zinc oxide in a mass ratio of 2~3:1, with the titanium dioxide particle size being 10~100 nm and the zinc oxide particle size being 20~100 nm.

8. The application of a plastic masterbatch produced by any one of claims 1-7 in spinning.