Synthesis method and application of carboxyl-terminated hyperbranched polycaprolactone hyperdispersant

Abstract

The application discloses a kind of synthesis method and application of carboxyl-terminated hyperbranched polycaprolactone hyperdispersant, comprising the following steps: step one, hyperbranched polyester, caprolactone monomer and catalyst one are added to reaction kettle, under the atmosphere of protective gas, reaction is carried out by heating, after reaction is finished, end hydroxyl hyperbranched polycaprolactone is obtained by devolatilization;Step two: after end hydroxyl hyperbranched polycaprolactone and succinic anhydride are heated and uniformly mixed, catalyst two is added, and the hydroxyl group is modified under solvent-free conditions, and carboxyl-terminated hyperbranched polycaprolactone is obtained.The application overcomes the conventional pain points of the existing traditional small molecule and high molecular dispersant, such as poor heat resistance, easy migration and precipitation, weak dispersion stability and other industry common problems, on the other hand, the high activity of the terminal segment can improve the interaction force between the inorganic filler and the resin interface, improve the dispersion of inorganic filler, and at the same time, avoid the excessive decline of the strength and toughness of the plastic matrix, that is, the defect of being unable to balance high filling and high mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, specifically to a method for synthesizing and applying a carboxyl-terminated hyperbranched polycaprolactone hyperdispersant. Background Technology

[0002] Currently, inorganic powders, plant fibers, and nano-functional fillers are widely used in the modification of plastics such as polylactic acid, polyethylene, and polypropylene, which can reduce costs and endow materials with functions such as heat resistance, flame retardancy, and high rigidity. However, fillers have strong surface polarity and high surface energy, which makes them prone to agglomeration in the plastic matrix. They also have poor compatibility with the resin interface and uneven dispersion, which can easily lead to a decrease in the mechanical properties of the products, an increase in surface defects, and a decrease in processing fluidity, thus limiting the widespread application of highly filled modified plastics.

[0003] Currently, commonly used industrial dispersants such as stearic acid, paraffin wax, polyethylene wax, and ordinary polymeric traditional dispersants have significant technical drawbacks: small molecule dispersants have poor heat resistance, are prone to decomposition and volatilization at high temperatures, are easily migrated and precipitated, and products are prone to blooming and whitening; traditional dispersants rely solely on physical coating or weak hydrogen bonding for dispersion, lacking strong chemical bonds with fillers and resins, resulting in weak interfacial bonding and a tendency for secondary agglomeration under high filling conditions; furthermore, traditional dispersants have limited functions, only improving dispersion and lubrication, often sacrificing material strength and toughness while enhancing filler dispersibility, making it difficult to achieve a balance between high filling and high toughness. Conventional linear polymeric dispersants have low branching and insufficient steric hindrance, limiting their dispersion effect on ultrafine and nanofillers, and lack additional functions such as toughening and flow promotion.

[0004] Hyperbranched polycaprolactone (PCV) possesses a three-dimensional spherical structure, low melt viscosity, good compatibility with plastic matrices, and inherent toughening and internal lubrication properties. However, its molecular ends are predominantly hydroxyl groups, resulting in insufficient polarity and reactivity, weak interfacial interaction with polar fillers, and limited dispersion and modification capabilities. Therefore, this invention provides a carboxyl-terminated hyperbranched PCV superdispersant. A prepolymer is prepared by initiating PCV polymerization with hyperbranched polyester, and then succinic anhydride is used to modify the hydroxyl groups into carboxyl groups. The strong hydrogen bonds and reactive bonds of the carboxyl groups enhance filler dispersion and interfacial bonding, while simultaneously increasing melt flow rate and providing toughening and reinforcing effects. This solves the technical challenge of traditional dispersants failing to simultaneously achieve high filler density and high toughness, making it suitable for various plastic filler modification applications. Summary of the Invention

[0005] This invention aims to provide a light-curable polyester acrylate with ultra-low acid value, high low-temperature resistance, and high reactivity, as well as its preparation method, to solve the problems of low-temperature embrittlement, high acid value, and poor hydrolysis resistance of existing products.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows: A method for synthesizing a carboxyl-terminated hyperbranched polycaprolactone hyperdispersant includes the following steps: Step 1: Add hyperbranched polyester, caprolactone monomer and catalyst 1 to the reactor, and carry out the reaction under a protective gas atmosphere by heating. After the reaction is completed, the hydroxyl-terminated hyperbranched polycaprolactone is obtained by devolatilization. Step 2: After heating and mixing the hydroxyl-terminated hyperbranched polycaprolactone and succinic anhydride, catalyst 2 is added to modify the hydroxyl groups under solvent-free conditions to obtain carboxyl-terminated hyperbranched polycaprolactone.

[0007] In a further improvement, the first catalyst is Sn(Oct)2 and the second catalyst is DMAP.

[0008] In a further improvement, the mass ratio of the hyperbranched polyester to caprolactone monomer is 200:847, the amount of catalyst one is 0.5wt%, and the mass ratio of hydroxyl-terminated hyperbranched polycaprolactone, succinic anhydride and catalyst two is 200:20-40:1.05. The hyperbranched polyester was purchased from Weihai Chenyuan Molecular New Materials Co., Ltd., with the brand name CYD-H20. The hyperbranched polyester is a hyperbranched polyester containing 16 hydroxyl functional groups.

[0009] Further improvements were made, with the mass ratio of hydroxyl-terminated hyperbranched polycaprolactone to succinic anhydride being 200:40.

[0010] Further improvements are made to the following specific steps in step one: Hyperbranched polyester and caprolactone monomers containing 16 hydroxyl functional groups are added to a reactor equipped with a mechanical stirrer. Nitrogen gas is introduced and purged three times, with nitrogen acting as a protective gas. The reactor temperature is raised to 40-60°C, and a vacuum pump is turned on for dehydration. After dehydration, nitrogen gas is introduced, and 20.5 wt% of catalyst Sn(Oct) is added. The temperature is raised to 150°C, and the polymerization reaction is maintained at this temperature for 6 hours. After the reaction is complete, a vacuum pump is used for devolatilization for 1-2 hours to obtain the hyperbranched polycaprolactone prepolymer.

[0011] Further improvements are made to the following steps in step two: hydroxyl-terminated hyperbranched polycaprolactone, succinic anhydride, and catalyst two are mixed in a reaction vessel, heated to 140°C, and the acid value is monitored. When the acid value no longer increases, the reaction is stopped, and the unreacted succinic anhydride is removed by vacuum distillation to obtain hydroxyl-terminated hyperbranched polycaprolactone.

[0012] A carboxyl-terminated hyperbranched polycaprolactone superdispersant, wherein the carboxyl-terminated hyperbranched polycaprolactone superdispersant is as described above.

[0013] The use of a carboxyl-terminated hyperbranched polycaprolactone superdispersant, wherein the carboxyl-terminated hyperbranched polycaprolactone superdispersant is used as a dispersant for plastic materials, as described above.

[0014] Further improvements include the use of polylactic acid, polyethylene, and polypropylene as plastic materials.

[0015] In a further improvement, the end-carboxyl hyperbranched polycaprolactone superdispersant is used as a toughening and reinforcing agent for plastic materials.

[0016] The beneficial effects of this invention are as follows: This invention overcomes the common pain points of existing traditional small molecule and high molecular weight dispersants, such as poor heat resistance, easy migration and precipitation, and weak dispersion stability. On the other hand, compared with other dispersants, the high activity of the terminal chain segment can enhance the interaction force with the inorganic filler and resin interface, improve the dispersibility of inorganic fillers, and avoid excessive reduction in the strength and toughness of the plastic matrix, that is, the defect of not being able to take into account both high filling and high mechanical properties. Attached Figure Description

[0017] The invention will be further illustrated with reference to the accompanying drawings, but the contents of the drawings do not constitute any limitation on the invention.

[0018] Figure 1 The infrared spectrum of hyperbranched polyester.

[0019] Figure 2 This is the carbon spectrum of a hyperbranched polyester.

[0020] Figure 3 The graph shows the 72-hour sedimentation rate of the products of Examples 1-3 and Comparative Examples 1-3. Detailed Implementation

[0021] To make the purpose, technical solution and advantages of the invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and examples, but the embodiments of the invention are not limited thereto.

[0022] Example of preparation of hyperbranched polycaprolactone prepolymer: 136 g of pentaerythritol and 1609 g of dimethylolpropionic acid were added to a reactor equipped with a condenser and mechanical stirrer. 8.725 g of p-toluenesulfonic acid catalyst was added under nitrogen protection. The mixture was heated to 150 °C and reacted for 5 hours. Water was removed under reduced pressure using a vacuum pump. The reaction was stopped when the acid value dropped to less than 20 mg KOH / g. The product was cooled and discharged to obtain a pale yellow solid. This hyperbranched polyester has 16 hydroxyl groups. (Infrared spectrum) Figure 1 It can be known that 3336cm -1 The peaks are the stretching vibration peaks of the hydroxyl group, at 2975, 2942, and 2884 cm⁻¹. -1 The peaks at 1722 cm⁻¹ represent the CH stretching peaks of methyl and methylene groups, while the peak at 1722 cm⁻¹ is a characteristic peak for ester carbonyl groups. (Based on carbon spectroscopy...) Figure 2It can be seen that 173.552ppm and 174.805ppm are ester carbon atoms, 64.187ppm is a secondary carbon atom, 46.658ppm, 48.709ppm and 51.102ppm are quaternary carbon atoms of branched, linear and terminal units, and 17.328ppm is a methyl carbon atom.

[0023] 200g of hyperbranched polyester containing 16 hydroxyl functional groups and 847g of caprolactone monomer were added to a reactor equipped with mechanical stirring. Nitrogen gas was introduced and purged three times as a protective gas. The reactor temperature was raised to 40-60℃, and a vacuum pump was turned on for dehydration. After dehydration, nitrogen gas and 25.235g of catalyst Sn(Oct) were introduced, and the temperature was raised to 150℃. The polymerization reaction was maintained at this temperature for 6 hours. After the reaction was completed, a vacuum pump was used for devolatilization for 1-2 hours to obtain a hyperbranched polycaprolactone prepolymer with a molecular weight of 8000, denoted as HPE-PCl. The hydroxyl value was 112mgKOH / g.

[0024] Example 1 200g of HPE-PCl, 20g of succinic anhydride, and 1.10g of DMAP were added to a reaction vessel equipped with mechanical stirring. The temperature was raised to 140℃ for reaction, and the acid value was measured. When the acid value no longer increased, the reaction was stopped. Unreacted succinic anhydride was removed by vacuum distillation to obtain modified carboxyl-terminated hyperbranched polycaprolactone with an acid value of 58mgKOH / g.

[0025] Example 2 200g of HPE-PCl, 30g of succinic anhydride, and 1.15g of DMAP were added to a reaction vessel equipped with mechanical stirring. The temperature was raised to 140℃ for reaction, and the acid value was measured. When the acid value no longer increased, the reaction was stopped. Unreacted succinic anhydride was removed by vacuum distillation to obtain modified carboxyl-terminated hyperbranched polycaprolactone with an acid value of 85mgKOH / g.

[0026] Example 3 200g of HPE-PCl, 40g of succinic anhydride, and 1.20g of DMAP were added to a reaction vessel equipped with mechanical stirring. The temperature was raised to 140℃ for reaction. The acid value was measured. When the acid value no longer increased, the reaction was stopped. Unreacted succinic anhydride was removed by vacuum distillation to obtain modified carboxyl-terminated hyperbranched polycaprolactone with an acid value of 110mgKOH / g.

[0027] Comparative Example 1 200g of HPE-PCl, 10g of succinic anhydride, and 1.05g of DMAP were added to a reaction vessel equipped with mechanical stirring. The temperature was raised to 140℃ for reaction, and the acid value was measured. When the acid value no longer increased, the reaction was stopped. Unreacted succinic anhydride was removed by vacuum distillation to obtain modified carboxyl-terminated hyperbranched polycaprolactone with an acid value of 28mgKOH / g.

[0028] Comparative Example 2 Unmodified HPE-PCl.

[0029] Comparative Example 3 Commercially available ethylene bis-stearamide (EBS).

[0030] The dispersion performance and high temperature resistance of the products in Examples 1-3 and the comparative examples were tested using calcium carbonate (light calcium carbonate). The test methods are as follows: 1. Dispersion performance test: 100g calcium carbonate, 2g superdispersant (2g unmodified HPCL added to Comparative Example 1, 2g commercially available EBS added to Comparative Example 2), and 150g toluene were added to a sand mill and ground for 30min to obtain a dispersion system. The viscosity (25℃), sedimentation stability (sedimentation rate after standing for 72h), and particle size distribution (D50) of the dispersion system were tested. 2. High temperature resistance test: Test its high temperature dispersion efficiency (compare with the room temperature dispersion efficiency and calculate the retention rate).

[0031] The test results are shown in Table 1 below: Table 1 Test data of Examples 1-3 and Comparative Examples 1-3 Test results show that the carboxyl-terminated hyperbranched polycaprolactone superdispersants of Examples 1-3 have significantly better dispersion performance and high-temperature resistance than Comparative Examples 1, 2, and 3 (ethylene bis-stearamide); with the increase of the carboxyl modification ratio, the viscosity of the dispersion system gradually decreases, and the sedimentation rate decreases significantly (see...). Figure 3 The particle size distribution is more uniform, and the dispersion stability is greatly improved. The dispersion effect is best when the acid value after modification reaches 110 mg KOH / g.

[0032] Application Examples The high-temperature lubricating, carboxyl-terminated hyperbranched polycaprolactone superdispersant of the present invention, based on its excellent dispersion performance and high-temperature resistance, can be widely used in conventional dispersion scenarios such as masterbatches and plastic fillers. The following detailed application examples illustrate its application: Application Example 1 This application example focuses on verifying the dual effects of high melt flow and toughening / reinforcing of the superdispersant of the present invention. Using polylactic acid (PLA, which is brittle, has poor melt flow, and is prone to agglomeration when highly filled) as a conventional polymer plastic matrix and calcium carbonate as a filler, EBS (Comparative Example 4) was set up as a comparison to verify the advantages of the product of the present invention over EBS in high-filler modification and to meet the high-performance modification requirements of polylactic acid.

[0033] Formula (by mass parts): 100 parts polylactic acid, 120 parts calcium carbonate (light calcium carbonate) (high filling ratio), 1 part of the superdispersant prepared in Example 4, and 0.5 parts of antioxidant 1010.

[0034] Blank group: 100 parts of polylactic acid (PLA), 120 parts of calcium carbonate, and 0.5 parts of antioxidant 1010.

[0035] Control group formulation (EBS comparison): 100 parts polylactic acid (PLA), 120 parts calcium carbonate, 1 part ethylene bis-stearamide (EBS), and 0.5 parts antioxidant 1010.

[0036] Preparation method: For the three groups of samples, the raw materials were premixed for 5 min in a high-speed mixer. After homogeneity, the mixture was fed into a twin-screw extruder (co-rotating, screw diameter 35 mm, L / D=40) for melt extrusion. The extrusion temperature was set to 170-190℃ (zone 1: 170℃, zone 2: 175℃, zone 3: 180℃, zone 4: 185℃, zone 5: 188℃, die head: 190℃), screw speed 200 r / min, and vacuum degree -0.06 MPa. The extrudate was water-cooled, pelletized, and then vacuum-dried at 80℃ for 4 h. Standard samples were injection molded using an injection molding machine (clamping force 80t) at an injection temperature of 185-195℃ and a mold temperature of 40℃ for performance testing. Melt flow rate was simultaneously tested to verify processing fluidity.

[0037] Test items and standards: melt flow rate (MFR, 190℃, 2.16kg, GB / T 3682-2018), flexural strength (GB / T 9341-2008), tensile strength (GB / T 1040.2-2006), impact strength (simply supported beam without notch, GB / T1043.1-2008), and filler dispersion uniformity (SEM observation).

[0038] Application Effects: The superdispersant group of this invention achieved a melt flow rate of 12.6 g / 10 min, which is 260% higher than the blank group and 41.6% higher than the control group. It exhibits excellent melt flowability, ensuring smooth extrusion and injection molding processes without mold clogging or melt fracture, demonstrating high melt flow efficiency. Tensile strength reached 51.3 MPa, elongation at break reached 10.8%, and impact strength reached 8.5 kJ / m², representing increases of 34.3%, 412.2%, and 203.6% respectively compared to the blank group, and increases of 15.3%, 111.8%, and 102.4% respectively compared to the EBS group, demonstrating significant toughening and reinforcing effects. SEM observation showed (… Figure 1 The calcium carbonate is uniformly dispersed in the PLA matrix without obvious agglomeration and the particle size is uniform. This is due to the three-dimensional branched structure (low viscosity and good compatibility) and highly active terminal carboxyl groups of the superdispersant of this invention. The terminal carboxyl groups form strong hydrogen bonds with the hydroxyl groups on the surface of calcium carbonate and the PLA molecular chains, which enhances the interfacial bonding force and achieves stable dispersion of the filler and tight bonding with the matrix, taking into account both flowability and mechanical properties.

[0039] Application Example 2 This application example uses high-density polyethylene (HDPE) as the conventional polymer plastic matrix and talc as a highly filled filler to further verify the dual effects of high melt flow and toughening and reinforcement of the super-dispersant of the present invention. EBS (Comparative Example 4) is used as a comparison to adapt to the high-filler and high-performance modification requirements of polyolefins.

[0040] Formula (by mass parts): 100 parts high-density polyethylene (HDPE), 120 parts talc (1250 mesh) (high filling ratio), 1.5 parts of the superdispersant prepared in Example 4, 1 part coupling agent DL-411, 2 parts compatibilizer CMG9801-GS, and 0.5 parts antioxidant 1010.

[0041] Blank group: 100 parts high-density polyethylene (HDPE), 120 parts talc (1250 mesh) (high filling ratio), 1 part coupling agent DL-411, 2 parts compatibilizer CMG9801-GS, and 0.5 parts antioxidant 1010.

[0042] Control group formulation (EBS comparison): 100 parts high-density polyethylene (HDPE), 120 parts talc (1250 mesh), 1.5 parts ethylene bis-stearamide (EBS, comparative example 4), 1 part coupling agent DL-411, 2 parts compatibilizer CMG9801-GS, and 0.5 parts antioxidant 1010.

[0043] The raw materials for the three sample groups were premixed in a high-speed mixer for 8 min each. After homogeneity, the mixture was fed into a twin-screw extruder (co-rotating, screw diameter 35 mm, L / D=40) for melt extrusion. The extrusion temperature was set to 180-200℃ (zone 1 180℃, zone 2 185℃, zone 3 190℃, zone 4 195℃, zone 5 198℃, die head 200℃), screw speed 180 r / min, and vacuum degree -0.06 MPa. The extrudate was water-cooled, pelletized, and then vacuum-dried at 60℃ for 3 h. Standard samples were injection molded using an injection molding machine at an injection temperature of 190-210℃ and a mold temperature of 30℃ for performance testing. Melt flow rate was tested simultaneously.

[0044] Application Effects: The superdispersant group of this invention achieved a melt flow rate of 7.7 g / 10 min, which is 493.3% higher than the blank group and 93.5% higher than the control group (EBS). It exhibits excellent processing fluidity, smooth extrusion granulation, and smooth, defect-free injection molded products. Its flexural strength, tensile strength, elongation at break, and impact strength are increased by 91.2%, 57.7%, 298.1%, and 148.4% respectively compared to the blank group, and by 36.8%, 32.7%, 132.6%, and 70.1% respectively compared to the EBS group. It demonstrates significant advantages in MFR, mechanical strength, and toughness, indicating that it possesses the triple functions of dispersion, interfacial reinforcement, and toughening. This is because the superdispersant of this invention retains the advantages of low viscosity, good compatibility, and self-toughening of hyperbranched polycaprolactone, while the highly active terminal carboxyl groups enhance the hydrogen bonding and interfacial bonding between the talc surface and the HDPE molecular chain, achieving a synergistic effect of dispersion, toughening, and improved processing fluidity.

[0045] Application Example 3 For conventional plastic filler modification (by mass parts): 100 parts polypropylene (PP), 20 parts carbon black (N330), 1.5 parts of the superdispersant prepared in Example 4, 0.2 parts of coupling agent NDZ-101, 0.5 parts of compatibilizer CMG9801-GS, and 1 part of antioxidant 1010.

[0046] Blank group: 100 parts of conventional PP, 20 parts of carbon black, 0.2 parts of coupling agent NDZ-101, 0.5 parts of compatibilizer CMG9801-GS, and 0.2 parts of antioxidant 1010.

[0047] Control group formulation (EBS comparison): 100 parts conventional PP, 20 parts carbon black, 1.5 parts ethylene bis-stearamide (EBS), 0.2 parts coupling agent NDZ-101, 0.5 parts compatibilizer CMG9801-GS, and 0.2 parts antioxidant 1010.

[0048] For the three samples, the raw materials were premixed for 10 min in a high-speed mixer (carbon black is prone to flying, so low-speed start is required). After uniform mixing, the mixture was fed into a twin-screw extruder at an extrusion temperature of 180-200℃ (zone 1: 180℃, zone 2: 185℃, zone 3: 190℃, zone 4: 195℃, die head: 200℃) and a screw speed of 200 r / min. After granulation, injection-molded standard samples were used for performance testing. Melt flow rate was tested simultaneously.

[0049] Application Results: The MFR of the superdispersant group of this invention reached 17.6 g / 10min (230℃ / 2.16kg), an increase of 282.6% compared to the blank group and 79.6% compared to the EBS group. Flexural strength, tensile strength, elongation at break, and impact strength increased by 36.2%, 59.0%, 216.0%, and 96.9% respectively compared to the blank group, and by 19.1%, 26.4%, 68.4%, and 39.4% respectively compared to the EBS group. Carbon black is a high specific surface area nanofiller, which easily forms a network structure leading to a sharp increase in melt viscosity. The superdispersant effectively breaks the carbon black network, releasing its fluidity. The steric hindrance effect of the three-dimensional hyperbranched structure prevents carbon black particles from approaching; the hydrogen bonding between the terminal carboxyl groups and the oxygen-containing functional groups (carboxyl and hydroxyl groups) on the carbon black surface achieves anchoring; the compatibility of the polycaprolactone segments with PP introduces the dispersed and stable carbon black into the matrix. This achieves uniform dispersion of carbon black, avoids "fish eyes" and color spots, and results in high surface gloss of the product, making it suitable for masterbatch and conductive modification fields.

[0050] Application Example 4 For conventional plastic filler modification (by mass parts): 100 parts PLA resin, 40 parts talc (1250 mesh), 1.5 parts of the superdispersant prepared in Example 4, and 0.2 parts of antioxidant 1010.

[0051] The raw materials were premixed in a high-speed mixer for 8 minutes until homogeneous, and then fed into a twin-screw extruder (co-rotating, screw diameter 35 mm, L / D=40) for melt extrusion. The extrusion temperature was set to 170-190℃ (zone 1 170℃, zone 2 175℃, zone 3 180℃, zone 4 185℃, zone 5 188℃, die head 190℃), screw speed 300 r / min, and vacuum degree -0.06MPa. The extrudate was water-cooled, pelletized, and then vacuum-dried at 60℃ for 4 h. Standard samples were injection molded using an injection molding machine (clamping force 80 t) at an injection temperature of 185-195℃ and a mold temperature of 40℃ for performance testing. The melt flow rate was tested simultaneously to verify processing fluidity.

[0052] Application Example 5 For conventional plastic filler modification (by mass parts): 100 parts PLA resin, 33 parts modified corn starch, 1.0 part of the superdispersant prepared in Example 4, and 0.2 parts of antioxidant 1010.

[0053] The preparation process is the same as in application example 4.

[0054] Application Example 6 For conventional plastic filler modification (by mass parts): 100 parts PLA resin, 5 parts silica, 1.0 part of the superdispersant prepared in Example 4, and 0.2 parts of antioxidant 1010.

[0055] The preparation process is the same as in application example 4.

[0056] As shown in the table above, the carboxyl-terminated modified hyperbranched polycaprolactone superdispersant of this invention exhibits excellent compatibility with various types of fillers, including talc, modified starch, and nano-silica. This superdispersant, relying on a hyperbranched, low-viscosity framework, significantly improves the melt flowability of the PLA-filled system and enhances processing performance. Simultaneously, the highly active end-carboxyl groups form strong interfacial hydrogen bonds with the filler and PLA molecular chains, resulting in uniform and stable filler dispersion and tight interfacial bonding. While effectively improving the tensile and flexural rigidity of the composite material, the flexible branched structure absorbs impact energy, significantly improving the brittleness of the PLA matrix. This achieves a synergistic effect of high flowability, high reinforcement, and high toughness, overcoming the shortcomings of traditional dispersants that are functionally singular and cannot simultaneously address mechanical and processing properties. It has a wide range of applications and significant comprehensive modification advantages.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for synthesizing a carboxyl-terminated hyperbranched polycaprolactone hyperdispersant, characterized in that, Includes the following steps: Step 1: Add hyperbranched polyester, caprolactone monomer and catalyst 1 to the reactor, and carry out the reaction under a protective gas atmosphere by heating. After the reaction is completed, the hydroxyl-terminated hyperbranched polycaprolactone is obtained by devolatilization. Step 2: After heating and mixing the hydroxyl-terminated hyperbranched polycaprolactone and succinic anhydride, catalyst 2 is added to modify the hydroxyl groups under solvent-free conditions to obtain carboxyl-terminated hyperbranched polycaprolactone.

2. The method for synthesizing the carboxyl-terminated hyperbranched polycaprolactone hyperdispersant as described in claim 1, characterized in that, The first catalyst is Sn(Oct)2, and the second catalyst is DMAP.

3. The method for synthesizing the carboxyl-terminated hyperbranched polycaprolactone hyperdispersant as described in claim 1, characterized in that, The mass ratio of hyperbranched polyester to caprolactone monomers is 200:847, and the amount of catalyst one is 0.5wt%; the mass ratio of hydroxyl-terminated hyperbranched polycaprolactone, succinic anhydride and catalyst two is 200:20-40:1.

05. The hyperbranched polyester was purchased from Weihai Chenyuan Molecular New Materials Co., Ltd., with the brand name CYD-H20. The hyperbranched polyester is a hyperbranched polyester containing 16 hydroxyl functional groups.

4. The method for synthesizing the carboxyl-terminated hyperbranched polycaprolactone hyperdispersant as described in claim 3, characterized in that, The mass ratio of hydroxyl-terminated hyperbranched polycaprolactone to succinic anhydride is 200:

40.

5. The method for synthesizing the carboxyl-terminated hyperbranched polycaprolactone hyperdispersant as described in claim 1, characterized in that, The specific steps of step one are as follows: Add hyperbranched polyester and caprolactone monomer containing 16 hydroxyl functional groups to a reactor equipped with a mechanical stirrer, purge with nitrogen gas and replace three times, using nitrogen as a protective gas; raise the reactor temperature to 40-60℃, turn on the vacuum pump for dehydration; after dehydration, purge with nitrogen gas, add catalyst Sn(Oct)2 0.5wt%, raise the temperature to 150℃, maintain the reaction temperature for polymerization reaction for 6h, and after the reaction is complete, use a vacuum pump for devolatilization for 1-2h to obtain hyperbranched polycaprolactone prepolymer.

6. The method for synthesizing the carboxyl-terminated hyperbranched polycaprolactone hyperdispersant as described in claim 1, characterized in that, The specific steps of step two are as follows: After mixing the terminal hydroxyl hyperbranched polycaprolactone, succinic anhydride and catalyst two in a reaction vessel, the mixture is heated to 140°C for reaction. The acid value is detected. When the acid value no longer increases, the reaction is stopped. The unreacted succinic anhydride is removed by vacuum distillation to obtain terminal carboxyl hyperbranched polycaprolactone.

7. A carboxyl-terminated hyperbranched polycaprolactone superdispersant, characterized in that, The carboxyl-terminated hyperbranched polycaprolactone hyperdispersant is as described in any one of claims 1-6.

8. The use of a carboxyl-terminated hyperbranched polycaprolactone superdispersant, characterized in that, The carboxyl-terminated hyperbranched polycaprolactone superdispersant is used as a dispersant for plastic materials, as described in claim 7.

9. The use of the carboxyl-terminated hyperbranched polycaprolactone hyperdispersant as described in claim 8, characterized in that, The plastic materials include polylactic acid, polyethylene, and polypropylene.

10. The use of the carboxyl-terminated hyperbranched polycaprolactone hyperdispersant as described in claim 8, characterized in that, The carboxyl-terminated hyperbranched polycaprolactone superdispersant is used as a toughening and reinforcing agent for plastic materials.

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