Low-haze monocyclic carboxylate nucleating agent and preparation method thereof

Abstract

The invention provides a low-haze monocyclic carboxylate nucleating agent and a preparation method thereof, and relates to the technical field of nucleating agents. The low-haze monocyclic carboxylate nucleating agent is prepared from the following raw materials in parts by weight: 70-80 parts of monocyclic carboxylate, 4-8 parts of an efficient antioxidant, 8-10 parts of dibenzylidene sorbitol, 4-8 parts of modified calcium carbonate, 3-6 parts of modified talcum powder and 1-3 parts of zinc stearate. The synergistic benefit of zinc stearate and the monocyclic carboxylate nucleating agent is utilized, so that the crystallization peak temperature of the plastic is greatly reduced, the requirements of low haze and high rigidity of the plastic are ensured, and meanwhile, the modified talcum powder and other inorganic fillers are matched to absorb and disperse heat generated in the processing and using processes of the plastic, so that the plastic has a good heat dissipation effect. The anti-yellowing performance and the heat stability of the plastic are improved by matching with an efficient antioxidant. Moreover, the dibenzylidene sorbitol nucleating agent is matched, so that the crystal size is reduced, the uniform distribution of crystals is promoted to the greatest extent, and the haze of the plastic is obviously reduced.

Description

Technical Field

[0001] This invention relates to the field of nucleating agent technology, specifically to a low-haze monocyclic carboxylate nucleating agent and its preparation method. Background Technology

[0002] Polyolefin materials such as polypropylene and polyethylene are widely used in packaging, automobiles, home appliances, and daily necessities due to their excellent comprehensive properties, low cost, and good processability. However, unmodified polyolefins typically have slow crystallization rates and low crystallinity, resulting in products with poor transparency (high haze), low gloss, insufficient rigidity, and long molding cycles. Adding nucleating agents is an effective way to solve these problems. Nucleating agents act as heterogeneous crystal nuclei, significantly increasing the polymer's crystallization rate and refining spherulite size, thereby improving the transparency, gloss, rigidity, and heat distortion temperature of the products, and shortening the molding cycle.

[0003] Currently, commonly used nucleating agents include organic carboxylate nucleating agents, which are dispersible polypropylene reinforcing and modifying nucleating agents that can improve the rigidity and surface hardness of polyolefin plastic products. Among them, hexahydrophthalic acid (HHPA) metal salts can provide polypropylene with excellent crystallization temperature, modulus, and acid scavenger compatibility.

[0004] However, in practical applications, existing hexahydrophthalic acid (HHPA) metal salt nucleating agents exhibit high haze when used for polypropylene nucleating agent modification, affecting the appearance quality of the final product and making them difficult to use in products requiring high transparency. Therefore, we propose a novel low-haze monocyclic carboxylate nucleating agent and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a low-haze monocyclic carboxylate nucleating agent and its preparation method. This system achieves synergistic effects among the components through the compounding of specific components and the surface modification of inorganic fillers. While ensuring high nucleation efficiency, it significantly reduces the haze of polymer products and improves their thermal stability.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-haze monocyclic carboxylate nucleating agent, prepared from the following raw materials in parts by weight: 70-80 parts of monocyclic carboxylate; 4-8 parts of high-efficiency antioxidant; 8-10 parts of dibenzyl sorbitol; 4-8 parts of modified calcium carbonate; 3-6 parts of modified talc; and 1-3 parts of zinc stearate.

[0007] Preferably, the method for preparing the modified calcium carbonate includes the following steps: a) Dry calcium carbonate at 80℃ for 24 hours; b) Mix the dried calcium carbonate, stearic acid and hydrolyzed silane coupling agent in a weight ratio of (18-22):(1-3):(1-3); c) Stir at 30 r / min for 10-15 min at 110℃; d) Cool the chamber temperature to 30°C to obtain the modified calcium carbonate.

[0008] Preferably, the preparation method of the modified talc powder includes the following steps: a) Surface hydroxylation treatment: Talc powder and sodium hydroxide solution with a mass fraction of 20% were mixed at a weight ratio of (0.5-1.5):(5-15), stirred at 80℃ and 300r / min for 6h, then washed with water three times and centrifuged, and then vacuum dried at 80℃ and 0.01MPa for 24h to obtain surface hydroxylated talc powder; b) Coupling agent modification: The surface-hydroxylated talc powder obtained in step a) is mixed with 75% ethanol solution and silane coupling agent in a weight ratio of (5-15):(80-90):(1-3). The mixture is stirred at 85℃ and 50r / min for 6h, then cooled to room temperature, washed three times with anhydrous ethanol, and vacuum dried at 80℃ for 24h to obtain the modified talc powder.

[0009] Preferably, in step b), the talc powder is first fully dispersed in a 75% ethanol solution before the silane coupling agent is added.

[0010] This invention also provides a method for preparing a low-haze monocyclic carboxylate nucleating agent, comprising the following steps: The monocyclic carboxylate, high-efficiency antioxidant, dibenzyl sorbitol, modified calcium carbonate, modified talc, and zinc stearate are added to a high-speed mixer in the specified weight ratio and mixed at 500-800 r / min for 15-30 minutes at room temperature to obtain the low-haze monocyclic carboxylate nucleating agent.

[0011] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes the synergistic effect of zinc stearate and monocyclic carboxylate nucleating agents to significantly reduce the crystallization peak temperature of plastics, ensuring the plastics meet the requirements of low haze and high rigidity. Simultaneously, the addition of modified talc and other inorganic fillers absorbs and disperses the heat generated during processing and use, further improving the thermal stability of the plastics. Furthermore, the addition of a high-efficiency antioxidant enhances the plastics' resistance to yellowing and improves thermal stability. Moreover, the use of dibenzyl sorbitol nucleating agents reduces crystal size and maximizes the uniform distribution of crystals, resulting in a significant reduction in the haze of the plastics. The monocyclic carboxylate nucleating agents provided by this invention exhibit very low hygroscopicity, significantly promote the crystallization process of plastics, improve the rigidity of plastics, and possess excellent comprehensive performance. Attached Figure Description

[0012] Figure 1 This is a schematic flowchart of the preparation method of modified talc powder in an embodiment of the present invention; Figure 2 This is a schematic diagram of the chemical formula of the monocyclic carboxylate in the embodiments of the present invention; Figure 3 This is a schematic diagram of the chemical formula of dibenzyl sorbitol in the embodiments of the present invention; Figure 4 This is a schematic flowchart illustrating the preparation method of modified calcium carbonate in an embodiment of the present invention. Detailed Implementation

[0013] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0014] Please see Figure 1 - Figure 4 This invention provides a low-haze monocyclic carboxylate nucleating agent, relating to the field of polymer material additives technology, and particularly to a nucleating agent for improving the optical and mechanical properties of polymers such as polyolefins.

[0015] This invention provides a low-haze monocyclic carboxylate nucleating agent, prepared from the following raw materials in parts by weight: 70-80 parts monocyclic carboxylate, 4-8 parts high-efficiency antioxidant, 8-10 parts dibenzyl sorbitol, 4-8 parts modified calcium carbonate, 3-6 parts modified talc, and 1-3 parts zinc stearate. Each component is carefully selected and proportioned, resulting in a synergistic effect. Zinc stearate, acting as a lubricant and dispersant, further promotes the uniform dispersion of the nucleating agent in the melt. The synergistic effect of all components achieves a synergistic effect greater than the sum of its parts (1+1>2).

[0016] The chemical formula of the monocyclic carboxylate is as follows: Figure 2 As shown; where M1 and M2 may be the same or different, and are selected from calcium or aluminum metal cations; R1-R 10 The nuclei can be the same or different, and can be selected from hydrogen atoms. The stereochemical formula of the asymmetric carbon atom on the ring can be cis or trans, but cis is preferred, as the cis structure has better nucleation properties.

[0017] In a further embodiment, the monocyclic carboxylate of the above structure can be prepared according to existing technology, such as invention patent CN1525992A, etc.

[0018] The chemical formula of the dibenzyl sorbitol is as follows: Figure 3 As shown; wherein R1 and R2 are independently selected from CH3CH2CH2 or CH3CH2CH2O; and wherein R3 is independently selected from CH2CH2CH3 or CH2CH=CH2. This type of dibenzylsorbitol, as an auxiliary nucleating agent, can produce a synergistic effect with the main nucleating agent monocyclic carboxylate, further refining the grain size.

[0019] In a further embodiment, the dibenzylidene sorbitol with the above structure can be prepared according to existing technology, such as invention patent CN101484458B.

[0020] Specifically, the preparation method of the modified calcium carbonate includes: drying CaCO3 at 80 ℃ for 24 h, mixing it with stearic acid and hydrolyzed silane coupling agent, stirring at 110 ℃ at 30 r / min for 10-15 min, and cooling the chamber temperature to 30 ℃ to obtain modified CaCO3. The weight ratio of the dried calcium carbonate, stearic acid, and silane coupling agent is (18-22):(1-3):(1-3). Through dual modification with stearic acid and silane coupling agent, the surface of calcium carbonate changes from hydrophilic to lipophilic, significantly improving its compatibility with the polyolefin matrix and effectively avoiding increased haze caused by agglomeration.

[0021] Meanwhile, the preparation method of the modified talc powder includes: placing talc powder in a 20% sodium hydroxide solution at 80℃, stirring at 300 r / min for 6 h, washing three times with water, centrifuging, and then vacuum drying at 80℃ and 0.01 MPa for 24 h to obtain surface-hydroxylated talc powder. The weight ratio of talc powder to sodium hydroxide solution is (0.5-1.5):(5-15). This step aims to clean the surface of the talc powder and introduce active hydroxyl groups.

[0022] Further, the surface-hydroxylated talc powder was added to a 75% ethanol solution and fully dispersed. Then, a silane coupling agent was added, and the mixture was stirred at 85°C and 50 r / min for 6 hours. After cooling to room temperature, the mixture was washed three times with anhydrous ethanol and dried under vacuum at 80°C for 24 hours to obtain the modified talc powder. The weight ratio of the surface-hydroxylated talc powder, 75% ethanol solution, and silane coupling agent was (5-15):(80-90):(1-3). The silane coupling agent, through the condensation reaction between its hydrolyzed silanol groups and the hydroxyl groups on the surface of the talc powder, and the organic functional groups at the other end, are compatible with the polymer matrix, thus acting as a bridge and improving dispersibility.

[0023] This invention also provides a method for preparing a low-haze monocyclic carboxylate nucleating agent, comprising the following steps: The monocyclic carboxylate, high-efficiency antioxidant, dibenzyl sorbitol, modified calcium carbonate, modified talc, and zinc stearate are added to a high-speed mixer in the specified weight ratio. The mixture is stirred at 500-800 rpm for 15-30 minutes at room temperature to obtain the low-haze monocyclic carboxylate nucleating agent. This method is simple, solvent-free, environmentally friendly, and easy for industrial production.

[0024] The present invention will be further explained below with reference to a more specific embodiment. In this invention, the silane coupling agent is KH560, which was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0025] Example 1 An embodiment of the present invention provides a low-haze monocyclic carboxylate nucleating agent, which is prepared from the following raw materials in parts by weight: 75 parts monocyclic carboxylate, 5 parts high-efficiency antioxidant, 9 parts dibenzyl sorbitol, 6 parts modified calcium carbonate, 5 parts modified talc, and 1 part zinc stearate.

[0026] The chemical formula of the monocyclic carboxylate is as follows: Figure 2 As shown; where M1 and M2 may be the same or different, and are selected from calcium or aluminum metal cations; R1-R 10 They can be the same or different, and can be chosen from hydrogen atoms. The stereochemical formula of the asymmetric carbon atom on the ring is cis.

[0027] The chemical formula of the dibenzyl sorbitol is as follows: Figure 3 As shown; wherein R1 and R2 are independently selected from CH3CH2CH2 or CH3CH2CH2O; and wherein R3 is independently selected from CH2CH2CH3 or CH2CH=CH2.

[0028] Specifically, the preparation method of the modified calcium carbonate includes: drying CaCO3 at 80 °C for 24 h, mixing it with stearic acid and hydrolyzed silane coupling agent, stirring at 110 °C at 30 r / min for 10-15 min, and cooling the chamber temperature to 30 °C to obtain modified CaCO3. The weight ratio of the dried calcium carbonate, stearic acid, and silane coupling agent is 20:2:2.

[0029] The preparation method of the modified talc powder includes: placing talc powder in a 20% sodium hydroxide solution at 80℃, stirring at 300 r / min for 6 h, washing three times with water, centrifuging, and then vacuum drying at 80℃ and 0.01 MPa for 24 h to obtain surface-hydroxylated talc powder. The weight ratio of talc powder to sodium hydroxide solution is 1:10.

[0030] Further, the surface-hydroxylated talc powder was added to a 75% ethanol solution and allowed to disperse fully. Then, a silane coupling agent was added, and the mixture was stirred at 85°C and 50 rpm for 6 hours. After cooling to room temperature, the mixture was washed three times with anhydrous ethanol and dried under vacuum at 80°C for 24 hours to obtain the modified talc powder. The weight ratio of the surface-hydroxylated talc powder, the 75% ethanol solution, and the silane coupling agent was 10:85:2.

[0031] Comparative Example 1 An embodiment of the present invention provides a low-haze monocyclic carboxylate nucleating agent, which is prepared from the following raw materials in parts by weight: 75 parts monocyclic carboxylate, 5 parts high-efficiency antioxidant, 6 parts modified calcium carbonate, 5 parts modified talc, and 1 part zinc stearate.

[0032] The chemical formula of the monocyclic carboxylate is as follows: Figure 2 As shown; where M1 and M2 may be the same or different, and are selected from calcium or aluminum metal cations; R1-R 10 They can be the same or different, and can be chosen from hydrogen atoms. The stereochemical formula of the asymmetric carbon atom on the ring is cis.

[0033] Specifically, the preparation method of the modified calcium carbonate includes: drying CaCO3 at 80 °C for 24 h, mixing it with stearic acid and hydrolyzed silane coupling agent, stirring at 110 °C at 30 r / min for 10-15 min, and cooling the chamber temperature to 30 °C to obtain modified CaCO3. The weight ratio of the dried calcium carbonate, stearic acid, and silane coupling agent is 20:2:2.

[0034] The preparation method of the modified talc powder includes: placing talc powder in a 20% sodium hydroxide solution at 80℃, stirring at 300 r / min for 6 h, washing three times with water, centrifuging, and then vacuum drying at 80℃ and 0.01 MPa for 24 h to obtain surface-hydroxylated talc powder. The weight ratio of talc powder to sodium hydroxide solution is 1:10.

[0035] Further, the surface-hydroxylated talc powder was added to a 75% ethanol solution and allowed to disperse fully. Then, a silane coupling agent was added, and the mixture was stirred at 85°C and 50 rpm for 6 hours. After cooling to room temperature, the mixture was washed three times with anhydrous ethanol and dried under vacuum at 80°C for 24 hours to obtain the modified talc powder. The weight ratio of the surface-hydroxylated talc powder, the 75% ethanol solution, and the silane coupling agent was 10:85:2.

[0036] Comparative Example 2 An embodiment of the present invention provides a low-haze monocyclic carboxylate nucleating agent, which is prepared from the following raw materials in parts by weight: 75 parts monocyclic carboxylate, 9 parts dibenzyl sorbitol, 6 parts modified calcium carbonate, 5 parts modified talc, and 1 part zinc stearate.

[0037] The chemical formula of the monocyclic carboxylate is as follows: Figure 2 As shown; where M1 and M2 may be the same or different, and are selected from calcium or aluminum metal cations; R1-R 10 They can be the same or different, and can be chosen from hydrogen atoms. The stereochemical formula of the asymmetric carbon atom on the ring is cis.

[0038] The chemical formula of the dibenzyl sorbitol is as follows: Figure 3 As shown; wherein R1 and R2 are independently selected from CH3CH2CH2 or CH3CH2CH2O; and wherein R3 is independently selected from CH2CH2CH3 or CH2CH=CH2.

[0039] Specifically, the preparation method of the modified calcium carbonate includes: drying CaCO3 at 80 °C for 24 h, mixing it with stearic acid and hydrolyzed silane coupling agent, stirring at 110 °C at 30 r / min for 10-15 min, and cooling the chamber temperature to 30 °C to obtain modified CaCO3. The weight ratio of the dried calcium carbonate, stearic acid, and silane coupling agent is 20:2:2.

[0040] The preparation method of the modified talc powder includes: placing talc powder in a 20% sodium hydroxide solution at 80℃, stirring at 300 r / min for 6 h, washing three times with water, centrifuging, and then vacuum drying at 80℃ and 0.01 MPa for 24 h to obtain surface-hydroxylated talc powder. The weight ratio of talc powder to sodium hydroxide solution is 1:10.

[0041] Further, the surface-hydroxylated talc powder was added to a 75% ethanol solution and allowed to disperse fully. Then, a silane coupling agent was added, and the mixture was stirred at 85°C and 50 rpm for 6 hours. After cooling to room temperature, the mixture was washed three times with anhydrous ethanol and dried under vacuum at 80°C for 24 hours to obtain the modified talc powder. The weight ratio of the surface-hydroxylated talc powder, the 75% ethanol solution, and the silane coupling agent was 10:85:2.

[0042] Comparative Example 3 An embodiment of the present invention provides a low-haze monocyclic carboxylate nucleating agent, which is prepared from the following raw materials in parts by weight: 75 parts monocyclic carboxylate, 5 parts high-efficiency antioxidant, 9 parts dibenzyl sorbitol, 6 parts modified calcium carbonate, and 1 part zinc stearate.

[0043] The chemical formula of the monocyclic carboxylate is as follows: Figure 2 As shown; where M1 and M2 may be the same or different, and are selected from calcium or aluminum metal cations; R1-R 10 They can be the same or different, and can be chosen from hydrogen atoms. The stereochemical formula of the asymmetric carbon atom on the ring is cis.

[0044] The chemical formula of the dibenzyl sorbitol is as follows: Figure 3 As shown; wherein R1 and R2 are independently selected from CH3CH2CH2 or CH3CH2CH2O; and wherein R3 is independently selected from CH2CH2CH3 or CH2CH=CH2.

[0045] Specifically, the preparation method of the modified calcium carbonate includes: drying CaCO3 at 80 °C for 24 h, mixing it with stearic acid and hydrolyzed silane coupling agent, stirring at 110 °C at 30 r / min for 10-15 min, and cooling the chamber temperature to 30 °C to obtain modified CaCO3. The weight ratio of the dried calcium carbonate, stearic acid, and silane coupling agent is 20:2:2.

[0046] Experimental Example: The nucleating agents prepared in Example 1 and Comparative Examples 1-3 were melt-extruded, blended, and granulated with polypropylene in a twin-screw extruder. The granules were then injection-molded into standard test strips. The nucleating agent weight relative to polypropylene was 1500 ppm, the melt extrusion temperature was 230°C, and the blended granules were dried and then molded into test samples on an injection molding machine for the following tests: 1. The flexural modulus of the prepared modified polypropylene was determined according to the national standard GB / T 9341-2008, as shown in Table 1.

[0047] 2. The haze of the prepared modified polypropylene was measured according to the national standard GB / T 2410-2008, as shown in Table 1.

[0048] 3. The yellowing index A of modified polypropylene was tested according to the method of GB24091980, as shown in Table 1.

[0049] Table 1. Test results of polypropylene materials As can be seen from Table 1, the modified polypropylene obtained using the examples of the present invention has a significantly increased flexural modulus and reduced haze compared with other comparative examples. The nucleating agent prepared in Example 1 of the present invention exhibits the best comprehensive performance in terms of haze, yellow index and mechanical properties, which fully demonstrates the superiority of the technical solution of the present invention.

[0050] The present invention provides a low-haze monocyclic carboxylate nucleating agent and its preparation method, which can effectively improve the nucleation performance of plastics and ensure the rigidity of plastics to the maximum extent while taking into account transparency.

[0051] Specifically, it employs a monocyclic carboxylate with a specific structure as the main nucleating agent, combined with dibenzyl sorbitol, to form a highly efficient nucleation system. More importantly, the inorganic fillers calcium carbonate and talc undergo fine surface modification, enabling them to achieve uniform nanoscale dispersion in the polymer matrix. These particles not only do not generate light scattering themselves but also act as heterogeneous nucleation sites, further refining spherulites. Together, they significantly reduce the haze of the product.

[0052] This invention provides a low-haze monocyclic carboxylate nucleating agent and its preparation method. The compound nucleating agent is composed of a stiffening-enhancing monocyclic calcium carboxylate nucleating agent, a transparency-enhancing nucleating agent, and other additives. These components have good compatibility with the monocyclic calcium carboxylate nucleating agent, which is beneficial to the dispersion of the nucleating agent. This not only reduces costs but also leverages the synergistic effect of the nucleating agents to improve the nucleating performance of plastic products, giving them good rigidity and achieving low haze.

[0053] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A low-haze monocyclic carboxylate nucleating agent, characterized in that, It is prepared from the following raw materials in parts by weight: 70-80 parts of monocyclic carboxylate; 4-8 parts of high-efficiency antioxidant; 8-10 parts of dibenzyl sorbitol; 4-8 parts of modified calcium carbonate; 3-6 parts of modified talc; and 1-3 parts of zinc stearate.

2. The low-haze monocyclic carboxylate nucleating agent according to claim 1, characterized in that, The method for preparing the modified calcium carbonate includes the following steps: a) Dry calcium carbonate at 80℃ for 24 hours; b) Mix the dried calcium carbonate, stearic acid and hydrolyzed silane coupling agent in a weight ratio of (18-22):(1-3):(1-3); c) Stir at 30 r / min for 10-15 min at 110℃; d) Cool the chamber temperature to 30°C to obtain the modified calcium carbonate.

3. The low-haze monocyclic carboxylate nucleating agent according to claim 1, characterized in that, The preparation method of the modified talc powder includes the following steps: a) Surface hydroxylation treatment: Talc powder and sodium hydroxide solution with a mass fraction of 20% were mixed at a weight ratio of (0.5-1.5):(5-15), stirred at 80℃ and 300r / min for 6h, then washed with water three times and centrifuged, and then vacuum dried at 80℃ and 0.01MPa for 24h to obtain surface hydroxylated talc powder; b) Coupling agent modification: The surface-hydroxylated talc powder obtained in step a) is mixed with 75% ethanol solution and silane coupling agent in a weight ratio of (5-15):(80-90):(1-3). The mixture is stirred at 85℃ and 50r / min for 6h, then cooled to room temperature, washed three times with anhydrous ethanol, and vacuum dried at 80℃ for 24h to obtain the modified talc powder.

4. The low-haze monocyclic carboxylate nucleating agent according to claim 3, characterized in that, In step b), talc powder is first fully dispersed in a 75% ethanol solution before adding the silane coupling agent.

5. A method for preparing a low-haze monocyclic carboxylate nucleating agent according to any one of claims 1-4, characterized in that, Includes the following steps: The monocyclic carboxylate, high-efficiency antioxidant, dibenzyl sorbitol, modified calcium carbonate, modified talc, and zinc stearate are added to a high-speed mixer in the specified weight ratio and mixed at 500-800 r / min for 15-30 minutes at room temperature to obtain the low-haze monocyclic carboxylate nucleating agent.

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