Cool-feeling master batch containing recycled polyester and processing technology of cool-feeling master batch

Abstract

The invention discloses a cool master batch containing recycled polyester and a processing technology of the cool master batch, and relates to the technical field of high polymer material preparation. In the application, hydroxyl-terminated cool-feeling polyester with good thermal stability and hydroxyl-terminated flexible polyester with relatively good toughness are prepared, the two polyesters with different functions are combined through isocyanate bonds at two ends of 1, 6-hexamethylene diisocyanate, and then are blended and melted with the regenerated polyester with a low melting point, so that the cool-feeling master batch containing the regenerated polyester is obtained; the two polyester chain segments with different functions both contain the antibacterial agent, the antibacterial agent is prepared from polyethyleneimine and resveratrol, through different antibacterial mechanisms of the two substances, the antibacterial range can be enlarged, the antibacterial effect can be enhanced, the two substances are grafted to the polyester chain segments through ester bonds, the precipitation risk is avoided, and the antibacterial reliability is further improved.

Description

Technical Field

[0001] This invention relates to the field of polymer material preparation technology, specifically a cooling masterbatch containing recycled polyester and its processing technology. Background Technology

[0002] Given the current scarcity of petroleum resources and the severe environmental pollution problem, non-petroleum-based materials have attracted much attention, with recycled materials being one of the key development directions. Recycled polyester, as the most commonly used engineering plastic and fiber raw material, faces increasingly higher functional requirements as people's living standards improve, such as UV resistance, antibacterial properties, and a cooling sensation.

[0003] CN104153035A discloses a flame-retardant and cooling recycled polyester filament fiber and its production method. By melt spinning recycled polyester with cooling masterbatch, a cooling recycled polyester filament fiber is obtained, providing people with a "cooling" "air-conditioning fiber" in the hot summer. However, in summer, sweating can lead to bacterial growth, so antibacterial properties are also important.

[0004] Therefore, we propose a cooling masterbatch containing recycled polyester and its processing technology, which prepares recycled polyester with low melting point and modified cooling polyester. By blending the two high-molecular polyester materials and melt extruding, we obtain a polyester masterbatch with both cooling and antibacterial functions. Summary of the Invention

[0005] The purpose of this invention is to provide a cooling masterbatch containing recycled polyester and its processing technology to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a processing method for a cooling masterbatch containing recycled polyester, comprising the following steps: Step 1: Wash and dry the waste polyester, then mix it with 2-methyl-1,3-propanediol and catalyst to carry out alcoholysis reaction, filter it to obtain alcoholysis product, and then mix it with stabilizer and antioxidant to carry out esterification reaction and polycondensation reaction in sequence to obtain low melting point recycled polyester. Step 2: Mix hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, and dimethyl sulfoxide, stir to dissolve, then add 1,6-hexamethylene diisocyanate, heat to reflux and react to obtain modified cooling polyester. Step 3: Mix the modified cooling polyester and the low-melting-point recycled polyester, dry, melt, and extrude granulate to obtain a cooling masterbatch containing recycled polyester.

[0007] Furthermore, in step 1, the mass ratio of waste polyester, 2-methyl-1,3-propanediol, catalyst, stabilizer, and antioxidant is 10:(30~50):(0.01~0.03):(0.005~0.010):(0.03~0.08).

[0008] Furthermore, in step 1, the catalyst is one or a mixture of manganese acetate, zinc acetate, and cobalt acetate; The stabilizer is one or a mixture of two of triphenyl phosphate and phosphorous acid. The antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 565, and antioxidant 1330, or a mixture thereof.

[0009] Furthermore, in step 1, the process conditions for the alcoholysis reaction are: temperature 200~210℃, time 1.8~2.2h; In step 1, the esterification reaction process conditions are: temperature 230~240℃, time 0.8~1.0h; In step 1, the process conditions for the polycondensation reaction are: temperature 240~250℃, time 3.0~3.5h.

[0010] Furthermore, in step 2, the mass ratio of hydroxyl-capped cooling polyester, hydroxyl-capped flexible polyester, dimethyl sulfoxide, and 1,6-hexamethylene diisocyanate is (3~7): (3~7): 30: (5~7).

[0011] Furthermore, in step 2, the process conditions for the reflux reaction are: temperature 78~82℃, time 6~8h.

[0012] Furthermore, in step 3, the mass ratio of modified cooling polyester to low melting point recycled polyester is 1:(1~3).

[0013] Furthermore, in step 3, the melting temperature is 190~200℃.

[0014] Furthermore, in step 2, the preparation process of the hydroxyl-terminated cooling polyester is as follows: S1: Triphenyltricarboxylic anhydride, tetrahydrofuran, and 4-dimethylaminopyridine are mixed, heated to 65-70°C, stirred evenly, and then menthol is added to carry out esterification reaction to obtain a carboxyl-containing menthol derivative. S2: Mix carboxyl-containing menthol derivative, hydroxyl-containing antibacterial agent, and tetrabutyl titanate, and heat the mixture under a nitrogen atmosphere. Then, increase the temperature to react again. After the reaction is complete, collect the precipitate, dry it, and obtain hydroxyl-terminated cooling polyester.

[0015] Furthermore, in S1, the mass ratio of trimellitic anhydride, tetrahydrofuran, 4-dimethylaminopyridine, and menthol is 10:(50~60):(0.1~0.3):(8~10).

[0016] Furthermore, in S1, the esterification reaction process conditions are: temperature 68~72℃, time 4~8h.

[0017] Furthermore, in S2, the mass ratio of the carboxylated menthol derivative, the hydroxyl-containing antibacterial agent, and the tetrabutyl titanate is 10:(15~20):(0.02~0.04).

[0018] Furthermore, in S2, the process conditions for the heating reaction are: temperature 160~170℃, time 2.5~3.0h; In S2, the process conditions for the heating reaction are: temperature 210~220℃, time 1~3h; In S2, the drying process conditions are: temperature 48~52℃, time 20~24h.

[0019] Furthermore, in step 2, the preparation process of the hydroxyl-terminated flexible polyester is as follows: Adipic acid, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate were mixed and heated under a nitrogen atmosphere. The mixture was then heated further to allow for further reaction. After the reaction was completed, the precipitate was collected, dried, and hydroxyl-terminated flexible polyester was obtained.

[0020] Furthermore, the mass ratio of adipic acid, hydroxyl-containing antibacterial agent, and tetrabutyl titanate is 10:(12~14):(0.02~0.04).

[0021] Furthermore, the process conditions for the heating reaction are: temperature 145~155℃, time 2.5~3.0h; The process conditions for the heating reaction are: temperature 165~175℃, time 2~4h; The drying process conditions are: temperature 48~52℃, time 20~24h.

[0022] Furthermore, the hydroxyl-containing antibacterial agent is prepared by the following process: Polyethyleneimine, aqueous acetic acid, and paraformaldehyde were mixed, stirred, and dissolved. Resveratrol was then added, and the mixture was heated in an oil bath to produce a hydroxyl-containing antibacterial agent.

[0023] Furthermore, the mass ratio of polyethyleneimine, aqueous acetic acid, paraformaldehyde, and resveratrol is 1:100:(0.12~0.22):(1.2~1.8). The volume fraction of the acetic acid aqueous solution is 40-50%.

[0024] Furthermore, the process conditions for the oil bath heating reaction are: temperature 90~100℃, time 2~4h.

[0025] In the above technical solution, the reaction mechanism of the preparation process of the hydroxyl-containing antibacterial agent is as follows: Under acidic conditions (acetic acid aqueous solution), the amino group of polyethyleneimine acts as a nucleophile to attack the formaldehyde generated by the depolymerization of paraformaldehyde, generating an imine intermediate. Then, the phenolic hydroxyl group of resveratrol attacks the imine intermediate to form a stable CN covalent bond, retaining the hydroxyl group in the raw material, and obtaining the hydroxyl-containing antibacterial agent. The reaction mechanism of the preparation process of hydroxyl-terminated flexible polyester is as follows: the carboxyl group of adipic acid and the hydroxyl group of hydroxyl-containing antibacterial agent undergo esterification reaction under the catalysis of tetrabutyl titanate, and the amount of hydroxyl-containing antibacterial agent added is controlled to be higher than that of adipic acid to obtain hydroxyl-terminated flexible polyester. The reaction mechanism for the preparation of hydroxyl-capped cooling polyester is as follows: Under the action of the catalyst 4-dimethylaminopyridine, the hydroxyl group of menthol attacks the anhydride bond of trimellitic anhydride, causing it to open the ring and obtain a carboxyl-containing menthol derivative; then the carboxyl-containing menthol derivative undergoes an esterification reaction with a hydroxyl-containing antibacterial agent, and the amount of hydroxyl-containing antibacterial agent added is controlled to be higher than that of the carboxyl-containing menthol derivative to obtain hydroxyl-capped cooling polyester; Finally, the modified cooling polyester is obtained by reacting the isocyanate bonds at both ends of the 1,6-hexamethylene diisocyanate with the terminal hydroxyl groups of the hydroxyl-capped flexible polyester and the hydroxyl-capped cooling polyester.

[0026] Compared with the prior art, the beneficial effects of the present invention are: 1. In this application, the hydroxyl-terminated cooling polyester segment is grafted with a menthol derivative structure via ester bonds. Compared with conventional menthol cooling agents, it has better long-lasting effect and no risk of precipitation. Furthermore, the menthol oxypropylene glycol used in this application has a boiling point of around 362.8℃ and good thermal stability, allowing it to exist stably during the melting process. The hydroxyl-containing antibacterial agent prepared in this application can expand the antibacterial range and enhance the antibacterial effect through the synergistic antibacterial effect of polyethyleneimine and resveratrol. Also, it is grafted onto the polyester segment via ester bonds, eliminating the risk of precipitation.

[0027] 2. In this application, 2-methyl-1,3-propanediol is used as an alcoholysis agent. Under high temperature and the action of a catalyst, the hydroxyl groups of 2-methyl-1,3-propanediol attack the ester bonds of the waste polyester to carry out an alcoholysis reaction, forming an oligomer with a side chain containing 2-methyl-1,3-propanediol. Then, esterification and polycondensation reactions are carried out to obtain a low-melting-point recycled polyester. The introduction of 2-methyl-1,3-propanediol destroys the regular structure of the polyester, which lowers the melting point of the recycled polyester and matches the melting point of the obtained modified cooling polyester.

[0028] 3. The hydroxyl-terminated flexible polyester in this application uses adipic acid as a raw material, which has good flexibility. Introducing it into the chain segment of the modified cooling polyester can improve the elongation at break of the polyester. Furthermore, adipic acid has good thermal stability and is biodegradable, which has certain environmental benefits.

[0029] 4. In this application, the modified cooling polyester is mixed with low-melting-point recycled polyester to obtain functional masterbatch, which reduces the amount of virgin plastics used and reduces pollution. The process used in this application does not produce toxic byproducts, and the solvents used are all low-toxicity solvents, which reduces wastewater discharge and has environmental protection significance. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the following specific implementation; The waste polyester comes from Huai'an Ruiyike Polymer Technology Co., Ltd. The catalyst is zinc acetate; The stabilizer is triphenyl phosphate; The antioxidant is antioxidant 1010; The recycled polyester bottle flakes are sourced from Huai'an Ruiyike Polymer Technology Co., Ltd.

[0032] Example 1: A processing method for a cooling masterbatch containing recycled polyester, comprising the following steps: (1) Preparation of hydroxyl-containing antibacterial agents: Polyethyleneimine, aqueous acetic acid, and paraformaldehyde were mixed and dissolved by stirring. Resveratrol was then added, and the mixture was heated in an oil bath to obtain a hydroxyl-containing antibacterial agent. The mass ratio of polyethyleneimine, aqueous acetic acid, paraformaldehyde, and resveratrol was 1:100:0.22:1.8. The volume fraction of the aqueous acetic acid was 50%. The process conditions for the oil bath heating reaction were: temperature 100℃, time 4h. (2) Preparation of hydroxyl-terminated flexible polyester: Adipic acid, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate were mixed and heated under a nitrogen atmosphere. The mixture was then heated further. After the reaction was complete, the precipitate was collected and dried to obtain a hydroxyl-terminated flexible polyester. The mass ratio of adipic acid, hydroxyl-containing antibacterial agent, and tetrabutyl titanate was 10:14:0.04. The heating reaction conditions were: temperature 155℃, time 3.0 h; the heating reaction conditions were: temperature 175℃, time 4 h; and the drying conditions were: temperature 52℃, time 24 h. (3) Preparation of hydroxyl-terminated cooling polyester: S1: Triphenyltricarboxylic anhydride, tetrahydrofuran, and 4-dimethylaminopyridine are mixed, heated to 70°C, stirred until homogeneous, and then menthol is added for esterification to obtain a carboxyl-containing menthol derivative; S2: The carboxyl-containing menthol derivative, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate are mixed and heated under a nitrogen atmosphere, followed by further heating. After the reaction is complete, the precipitate is collected and dried to obtain a hydroxyl-terminated cooling polyester; In S1, trimellitic anhydride, tetrahydrofuran, 4-dimethylaminopyridine, and menthol are present in the esterification reaction. The mass ratio of propylene glycol is 10:60:0.3:10; in S1, the esterification reaction conditions are: temperature 72℃, time 8h; in S2, the mass ratio of carboxylated menthol derivative, hydroxyl-containing antibacterial agent, and tetrabutyl titanate is 10:20:0.04; in S2, the heating reaction conditions are: temperature 170℃, time 3.0h; in S2, the temperature-raising reaction conditions are: temperature 220℃, time 3h; in S2, the drying process conditions are: temperature 52℃, time 24h. (4) Preparation of cooling masterbatch containing recycled polyester: Step 1: Wash and dry the waste polyester, then mix it with 2-methyl-1,3-propanediol and a catalyst for alcoholysis. Filter the mixture to obtain the alcoholysis product, then mix it with a stabilizer and antioxidant for esterification and polycondensation to obtain a low-melting-point recycled polyester. Step 2: Mix hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, and dimethyl sulfoxide, stir to dissolve, then add 1,6-hexamethylene diisocyanate and reflux to obtain a modified cooling polyester. Step 3: Mix the modified cooling polyester and the low-melting-point recycled polyester, dry, melt, and extrude to granulate, obtaining a cooling masterbatch containing recycled polyester. In Step 1, the waste polyester, 2-methyl-1,3-propanediol, catalyst, stabilizer, and antioxidant... The mass ratio is 10:50:0.03:0.01:0.08; in step 1, the process conditions for the alcoholysis reaction are: temperature 210℃, time 2.2h; in step 1, the process conditions for the esterification reaction are: temperature 240℃, time 1.0h; in step 1, the process conditions for the polycondensation reaction are: temperature 250℃, time 3.5h; in step 2, the mass ratio of hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, dimethyl sulfoxide, and 1,6-hexamethylene diisocyanate is 3:7:30:7; in step 2, the process conditions for the reflux reaction are: temperature 82℃, time 8h; in step 3, the mass ratio of modified cooling polyester and low-melting-point recycled polyester is 1:3; in step 3, the melting temperature is 200℃.

[0033] Example 2: A processing method for a cooling masterbatch containing recycled polyester, comprising the following steps: (1) Preparation of hydroxyl-containing antibacterial agents: Polyethyleneimine, aqueous acetic acid, and paraformaldehyde were mixed and dissolved by stirring. Resveratrol was then added, and the mixture was heated in an oil bath to obtain a hydroxyl-containing antibacterial agent. The mass ratio of polyethyleneimine, aqueous acetic acid, paraformaldehyde, and resveratrol was 1:100:0.18:1.6. The volume fraction of the aqueous acetic acid was 45%. The process conditions for the oil bath heating reaction were: temperature 95℃, time 3h. (2) Preparation of hydroxyl-terminated flexible polyester: Adipic acid, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate were mixed and heated under a nitrogen atmosphere. The mixture was then heated further. After the reaction was complete, the precipitate was collected and dried to obtain a hydroxyl-terminated flexible polyester. The mass ratio of adipic acid, hydroxyl-containing antibacterial agent, and tetrabutyl titanate was 10:13:0.03. The heating reaction conditions were: temperature 150℃, time 2.8h; the heating reaction conditions were: temperature 170℃, time 3h; and the drying conditions were: temperature 50℃, time 22h. (3) Preparation of hydroxyl-terminated cooling polyester: S1: Tripterygic anhydride, tetrahydrofuran, and 4-dimethylaminopyridine are mixed, heated to 68°C, stirred until homogeneous, and then menthol is added for esterification to obtain a carboxyl-containing menthol derivative; S2: The carboxyl-containing menthol derivative, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate are mixed and heated under a nitrogen atmosphere, followed by further heating. After the reaction is complete, the precipitate is collected and dried to obtain a hydroxyl-terminated cooling polyester; In S1, trimellitic anhydride, tetrahydrofuran, 4-dimethylaminopyridine, and menthol are present in the esterification reaction. The mass ratio of propylene glycol is 10:55:0.2:9; in S1, the esterification reaction conditions are: temperature 70℃, time 6h; in S2, the mass ratio of carboxylated menthol derivative, hydroxyl-containing antibacterial agent, and tetrabutyl titanate is 10:18:0.03; in S2, the heating reaction conditions are: temperature 165℃, time 2.8h; in S2, the temperature-raising reaction conditions are: temperature 215℃, time 2h; in S2, the drying process conditions are: temperature 50℃, time 22h. (4) Preparation of cooling masterbatch containing recycled polyester: Step 1: Wash and dry the waste polyester, then mix it with 2-methyl-1,3-propanediol and a catalyst for alcoholysis. Filter the mixture to obtain the alcoholysis product, then mix it with a stabilizer and antioxidant for sequential esterification and polycondensation to obtain a low-melting-point recycled polyester. Step 2: Mix hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, and dimethyl sulfoxide, stir to dissolve, then add 1,6-hexamethylene diisocyanate and reflux to obtain a modified cooling polyester. Step 3: Mix the modified cooling polyester and the low-melting-point recycled polyester, dry, melt, and extrude to granulate, obtaining a cooling masterbatch containing recycled polyester. In Step 1, the waste polyester, 2-methyl-1,3-propanediol, catalyst, stabilizer, and antioxidant are of different qualities. The mass ratio is 10:40:0.02:0.008:0.05; in step 1, the process conditions for the alcoholysis reaction are: temperature 205℃, time 2.0h; in step 1, the process conditions for the esterification reaction are: temperature 235℃, time 0.9h; in step 1, the process conditions for the polycondensation reaction are: temperature 245℃, time 3.2h; in step 2, the mass ratio of hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, dimethyl sulfoxide, and 1,6-hexamethylene diisocyanate is 5:5:30:6; in step 2, the process conditions for the reflux reaction are: temperature 80℃, time 7h; in step 3, the mass ratio of modified cooling polyester and low-melting-point recycled polyester is 1:2; in step 3, the melting temperature is 195℃.

[0034] Example 3: A processing method for a cooling masterbatch containing recycled polyester, comprising the following steps: (1) Preparation of hydroxyl-containing antibacterial agents: Polyethyleneimine, aqueous acetic acid, and paraformaldehyde were mixed and dissolved by stirring. Resveratrol was then added, and the mixture was heated in an oil bath to obtain a hydroxyl-containing antibacterial agent. The mass ratio of polyethyleneimine, aqueous acetic acid, paraformaldehyde, and resveratrol was 1:100:0.12:1.2. The volume fraction of the aqueous acetic acid was 40%. The process conditions for the oil bath heating reaction were: temperature 90℃, time 2h. (2) Preparation of hydroxyl-terminated flexible polyester: Adipic acid, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate were mixed and heated under a nitrogen atmosphere. The mixture was then heated further. After the reaction was complete, the precipitate was collected and dried to obtain a hydroxyl-terminated flexible polyester. The mass ratio of adipic acid, hydroxyl-containing antibacterial agent, and tetrabutyl titanate was 10:12:0.02. The heating reaction conditions were: temperature 145℃, time 2.5h; the heating reaction conditions were: temperature 165℃, time 2h; and the drying conditions were: temperature 48℃, time 20h. (3) Preparation of hydroxyl-terminated cooling polyester: S1: Triphenyltricarboxylic anhydride, tetrahydrofuran, and 4-dimethylaminopyridine are mixed, heated to 65°C, stirred until homogeneous, and then menthol is added for esterification to obtain a carboxyl-containing menthol derivative; S2: The carboxyl-containing menthol derivative, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate are mixed and heated under a nitrogen atmosphere, followed by further heating. After the reaction is complete, the precipitate is collected and dried to obtain a hydroxyl-terminated cooling polyester; In S1, triphenyltricarboxylic anhydride, tetrahydrofuran, 4-dimethylaminopyridine, and menthol are present in the esterification reaction. The mass ratio of propylene glycol is 10:50:0.1:8; in S1, the esterification reaction conditions are: temperature 68℃, time 4h; in S2, the mass ratio of carboxylated menthol derivative, hydroxyl-containing antibacterial agent, and tetrabutyl titanate is 10:15:0.02; in S2, the heating reaction conditions are: temperature 160℃, time 2.5h; in S2, the temperature-raising reaction conditions are: temperature 210℃, time 1h; in S2, the drying process conditions are: temperature 48℃, time 20h. (4) Preparation of cooling masterbatch containing recycled polyester: Step 1: Wash and dry the waste polyester, then mix it with 2-methyl-1,3-propanediol and a catalyst for alcoholysis. Filter the mixture to obtain the alcoholysis product, then mix it with a stabilizer and antioxidant for sequential esterification and polycondensation to obtain a low-melting-point recycled polyester. Step 2: Mix hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, and dimethyl sulfoxide, stir to dissolve, then add 1,6-hexamethylene diisocyanate and reflux to obtain a modified cooling polyester. Step 3: Mix the modified cooling polyester and the low-melting-point recycled polyester, dry, melt, and extrude to granulate, obtaining a cooling masterbatch containing recycled polyester. In Step 1, the waste polyester, 2-methyl-1,3-propanediol, catalyst, stabilizer, and antioxidant are of different qualities. The mass ratio is 10:30:0.01:0.005:0.03; in step 1, the process conditions for the alcoholysis reaction are: temperature 200℃, time 1.8h; in step 1, the process conditions for the esterification reaction are: temperature 230℃, time 0.8h; in step 1, the process conditions for the polycondensation reaction are: temperature 240℃, time 3.0h; in step 2, the mass ratio of hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, dimethyl sulfoxide, and 1,6-hexamethylene diisocyanate is 7:3:30:5; in step 2, the process conditions for the reflux reaction are: temperature 78℃, time 6h; in step 3, the mass ratio of modified cooling polyester and low-melting-point recycled polyester is 1:1; in step 3, the melting temperature is 190℃.

[0035] Comparative Example 1: Compared with Example 1, menthol was replaced with menthol, and the other conditions remained the same as in Example 1.

[0036] Comparative Example 2: Compared with Example 1, the hydroxyl-containing antibacterial agent was replaced with ethylparaben, and the other conditions remained the same as in Example 1.

[0037] Comparative Example 3: Compared with Example 1, the low-melting-point recycled polyester was replaced with ordinary recycled polyester bottle flakes, the melting temperature was adjusted to 260°C, and the other conditions remained unchanged, the same as in Example 1.

[0038] Comparative Example 4: Compared with Example 1, menthol was replaced with menthol, hydroxyl-containing antibacterial agent was replaced with ethyl para-hydroxybenzoate, low-melting-point recycled polyester was replaced with recycled polyester flakes, the melting temperature was adjusted to 260°C, and the other conditions remained unchanged.

[0039] Experiment: The cooling masterbatches obtained in Examples 1-3 and Comparative Examples 1-4 were tested for various properties; Contact cooling test: The contact cooling coefficient of the cooling masterbatch was tested using a contact cooling and warming tester to characterize its contact cooling sensation; Tensile property test: The elongation at break of the cool-feeling masterbatch was tested in accordance with GB / T 1040.1-2025 to characterize its tensile properties. Antibacterial test: The antibacterial rate of the cooling masterbatch was tested in accordance with GB / T 20944.3-2008 to characterize its antibacterial properties;

[0040]

[0041] Based on the data in the table above, the following conclusions can be drawn: Compared to Example 1, the contact cooling coefficient of Comparative Example 1 decreased because menthol oxypropylene glycol has higher thermal stability than menthol and is less prone to oxidation or decomposition during melting. The inhibition rates of *Escherichia coli* and *Staphylococcus epidermidis* in Comparative Example 2 decreased significantly because ethylparaben has weak inhibitory effects on these two bacteria, demonstrating that the synergistic effect of the two antibacterial substances used in this application can increase the antibacterial range and efficacy. All properties decreased in Comparative Example 3 because the melting temperature of ordinary polyester bottle flakes is relatively high; at 240-260°C, the modified cooling polyester prepared in this application undergoes thermal decomposition, resulting in performance degradation. The performance degradation was even more pronounced in Comparative Example 4. As can be seen from the above, the settings of each process and the materials used in this application can promote the comprehensive improvement of the contact cooling coefficient, mechanical properties and antibacterial properties of the produced cooling masterbatch.

[0042] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A cooling masterbatch containing recycled polyester, characterized in that: It includes the following components: low-melting-point recycled polyester and modified cooling polyester; The low-melting-point recycled polyester is prepared by depolymerizing waste polyester with 2-methyl-1,3-propanediol, then mixing it with stabilizers and antioxidants, and then carrying out esterification and polycondensation reactions in sequence. The modified cooling polyester is prepared by reacting hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, and 1,6-hexamethylene diisocyanate.

2. A processing method for a cooling masterbatch containing recycled polyester, characterized in that: Includes the following steps: Step 1: Wash and dry the waste polyester, then mix it with 2-methyl-1,3-propanediol and catalyst to carry out alcoholysis reaction, filter it to obtain alcoholysis product, and then mix it with stabilizer and antioxidant to carry out esterification reaction and polycondensation reaction in sequence to obtain low melting point recycled polyester. Step 2: Mix hydroxyl-terminated cooling polyester, hydroxyl-terminated flexible polyester, and dimethyl sulfoxide, stir to dissolve, then add 1,6-hexamethylene diisocyanate, heat to reflux and react to obtain modified cooling polyester. Step 3: Mix the modified cooling polyester and the low-melting-point recycled polyester, dry, melt, and extrude granulate to obtain a cooling masterbatch containing recycled polyester.

3. The processing technology of a cooling masterbatch containing recycled polyester according to claim 2, characterized in that: The preparation process of the hydroxyl-terminated cooling polyester is as follows: S1: Triphenyltricarboxylic anhydride, tetrahydrofuran, and 4-dimethylaminopyridine are mixed, heated to 65-70°C, stirred evenly, and then menthol is added to carry out esterification reaction to obtain a carboxyl-containing menthol derivative. S2: Mix carboxyl-containing menthol derivative, hydroxyl-containing antibacterial agent, and tetrabutyl titanate, and heat the mixture under a nitrogen atmosphere. Then, increase the temperature to react again. After the reaction is complete, collect the precipitate, dry it, and obtain hydroxyl-terminated cooling polyester.

4. The processing technology of a cooling masterbatch containing recycled polyester according to claim 2, characterized in that: The preparation process of the hydroxyl-terminated flexible polyester is as follows: Adipic acid, a hydroxyl-containing antibacterial agent, and tetrabutyl titanate were mixed and heated under a nitrogen atmosphere. The mixture was then heated further to allow for further reaction. After the reaction was completed, the precipitate was collected, dried, and hydroxyl-terminated flexible polyester was obtained.

5. The processing technology of a cooling masterbatch containing recycled polyester according to claim 3, characterized in that: The hydroxyl-containing antibacterial agent is prepared by the following process: Polyethyleneimine, aqueous acetic acid, and paraformaldehyde were mixed, stirred, and dissolved. Resveratrol was then added, and the mixture was heated in an oil bath to produce a hydroxyl-containing antibacterial agent.

6. The processing technology of a cooling masterbatch containing recycled polyester according to claim 2, characterized in that: In step 1, the mass ratio of waste polyester, 2-methyl-1,3-propanediol, catalyst, stabilizer, and antioxidant is 10:(30~50):(0.01~0.03):(0.005~0.01):(0.03~0.08).

7. The processing technology of a cooling masterbatch containing recycled polyester according to claim 3, characterized in that: In S1, the mass ratio of trimellitic anhydride, tetrahydrofuran, 4-dimethylaminopyridine, and menthol is 10:(50~60):(0.1~0.3):(8~10).

8. The processing technology of a cooling masterbatch containing recycled polyester according to claim 2, characterized in that: In step 3, the melting temperature is 190~200℃.

9. The processing technology of a cooling masterbatch containing recycled polyester according to claim 2, characterized in that: In step 1, the catalyst is one or a mixture of manganese acetate, zinc acetate, and cobalt acetate; The stabilizer is one or a mixture of two of triphenyl phosphate and phosphorous acid. The antioxidant is one or more of antioxidant 1010, antioxidant 1076, antioxidant 565, and antioxidant 1330, or a mixture thereof.

10. The processing method of a cooling masterbatch containing recycled polyester according to claim 4, characterized in that: The mass ratio of adipic acid, hydroxyl-containing antibacterial agent, and tetrabutyl titanate is 10:(12~14):(0.02~0.04).

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