Preparation of a nylon 6 dual-purpose auxiliary and its application in nylon 6

Abstract

The application discloses a preparation method of a nylon 6 double-effect auxiliary agent and application thereof, relates to the technical field of high polymer materials, and can play a heterogeneous nucleation role in the nylon 6, and the oleic acid amide chain segment in the double-effect auxiliary agent can play a lubricating role, promote the rearrangement of the nylon 6 molecular chain, increase the crystallization temperature, accelerate the crystallization rate, and thus improve the crystallization performance. The nylon 6 added with the double-effect auxiliary agent prepared by the method has excellent nucleation and lubricating effects, and has important significance for expanding the application range of the nylon 6.

Description

Technical Field

[0001] This invention relates to the preparation of a dual-effect additive for nylon 6 and its application in nylon 6, belonging to the field of polymer materials technology. Background Technology

[0002] Nylon 6 is one of the most important thermoplastic engineering plastics, possessing excellent comprehensive properties and widely used in automotive engineering materials, electronic and electrical materials, packaging materials, and other fields. However, its relatively low crystallization temperature and slow crystallization rate limit its high-value utilization. With rapid societal development, improving the crystallinity of nylon 6 has become a pressing research challenge to broaden its application areas. The industry often chooses to blend and modify nylon 6 with fillers and additives. However, research on dedicated additives for nylon 6 that can simultaneously exert multiple synergistic effects is limited. Therefore, there is an urgent need to develop a dual-effect additive to improve the crystallinity of nylon 6, thereby solving practical problems in its applications. Summary of the Invention

[0003] To address the technical problems existing in the prior art, this invention provides a method for preparing a dual-effect nylon 6 additive and its application in nylon 6. The additive has a stable molecular structure, can improve the crystallization properties of nylon 6, and can broaden the application range of nylon 6.

[0004] The present invention provides a nylon 6 dual-effect additive, characterized in that its molecular structure is shown in the following formula:

[0005] A method for preparing a nylon 6 dual-effect additive, characterized in that the preparation method includes the following steps: 30 g of oleamide was dissolved in 100 mL of acetone, and 21 mL of 4-tert-butylbenzoyl chloride was added. The mixture was stirred at 40 °C for 18 h. After the reaction was completed, the mixture was washed with 200 mL of acetone until the pH of the system was 7. The product was then dried in an oven at 70 °C to constant weight to obtain the nylon 6 dual-effect additive.

[0006] Furthermore, drying temperatures that are too high or too low will not guarantee the drying effect. The above-mentioned impurity removal and drying conditions are the optimal conditions verified through experiments.

[0007] The various reaction conditions and parameters in the preparation method of Nylon 6 dual-effect additive described in this invention are all optimal conditions that have been verified by experiments.

[0008] In addition, in the application of the nylon 6 dual-effect additive described in this invention, the addition amount of the above-mentioned special additive is 1%-5%.

[0009] Preferably, the amount of the nylon 6 dual-effect additive added is 2% of nylon 6.

[0010] The amount of the nylon 6 dual-effect additive synthesized in this invention must be appropriate in order to exert the dual-effect effect and enable nylon 6 to obtain better crystallization properties. The above-mentioned addition amount is the optimal condition verified by experiments.

[0011] Compared with the prior art, the present invention has the following technical effects.

[0012] 1. The oleic acid amide segment in this nylon 6 dual-effect additive can act as a lubricant, promote the rearrangement of nylon 6 molecular chains, increase the crystallization temperature, and thus further improve its crystallization performance.

[0013] 2. This nylon 6 dual-effect additive can play a role in heterogeneous nucleation, accelerate the crystallization rate, and thus improve its crystallization performance.

[0014] 3. The reactants of this dual-effect nylon 6 additive are chemically combined to obtain an additive that can take into account both nucleation and lubrication functions and has a stable molecular structure. It will not decompose during the hot processing of nylon 6, requires a small amount, and has a significant effect. Specific implementation methods

[0015] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. Unless otherwise specified, all raw materials in the embodiments are conventional raw materials and commercially available products. The specific embodiments of this invention will be compared with comparative examples below to further illustrate the effect of this invention on the crystallization properties of nylon 6.

[0016] Example 1 30 g of oleamide (CAS: 301-02-0) was dissolved in 100 mL of acetone, and 21 mL of 4-tert-butylbenzoyl chloride (CAS: 1710-98-1) was added. The mixture was stirred at 40 °C for 18 h. After the reaction was completed, the mixture was washed with 200 mL of acetone until the pH of the system was 7. The product was then dried in an oven at 70 °C to constant weight to obtain the nylon 6 dual-effect additive.

[0017] Nylon 6 and the aforementioned nylon 6 dual-effect additive were mixed in a high-speed mixer at a mass ratio of 100:2 (mixing speed 3000 rpm, mixing time 5 min). The mixture was then extruded and granulated in a conventional twin-screw extruder, and finally injection molded into test samples. The crystallization temperature of the samples was determined according to the method described in GB / T 19466.3-2004. T c 6 mg of the above sample was placed in an aluminum crucible and then placed in a differential scanning calorimeter (DSC). The half-crystallization time of the resulting mixture was measured by DSC.t 1 / 2 The specific process is as follows: The temperature is increased to 250℃ at a rate of 10℃ / min and held for 3 min; then the temperature is decreased to 180℃ at a rate of 40℃ / min and held for 60 min; finally, the temperature is decreased to 40℃ at a rate of 10℃ / min. The relative crystallinity X(t) is calculated using the following formula based on the isothermal curve, and the half-crystal time is obtained based on the relative crystallinity X(t) = 0.5. t 1 / 2 ), the specific data is shown in Table 1;

[0018] Example 2 This embodiment is basically the same as embodiment 1, except that the mass ratio of nylon 6 and nylon 6 dual-effect additive is 100:1. The test data is shown in Table 1.

[0019] Example 3 This embodiment is basically the same as embodiment 1, except that the mass ratio of nylon 6 and nylon 6 dual-effect additive is 100:5. The test data is shown in Table 1.

[0020] Comparative Example 1 Pure nylon 6 was extruded and granulated in a conventional twin-screw extruder, and then injection molded into test samples using an injection molding machine. The crystallization temperature was determined according to the method in Example 1. T c and half-crystal time ( t 1 / 2 ), and the specific data is shown in Table 1.

[0021] Comparative Example 2 Nylon 6 and oleamide were mixed at a mass ratio of 100:2 in a high-speed mixer (mixing speed 3000 rpm, mixing time 5 min). The mixture was then extruded and granulated in a conventional twin-screw extruder, and finally injection molded to obtain test samples. The crystallization temperature was determined according to the method in Example 1. T c and half-crystal time ( t 1 / 2 ), and the specific data is shown in Table 1.

[0022] Comparative Example 3 Nylon 6 and 4-tert-butylbenzoyl chloride were mixed in a high-speed mixer at a mass ratio of 100:2 (mixing speed 3000 rpm, mixing time 5 min). The mixture was then extruded and granulated in a conventional twin-screw extruder, and finally injection molded to obtain the test sample. The crystallization temperature was determined according to the method in Example 1. T c and half-crystal time ( t1 / 2 ), and the specific data is shown in Table 1.

[0023] Comparative Example 4 30 g of oleamide and 21 mL of 4-tert-butylbenzoyl chloride were physically mixed in a container (mixing speed 3000 rpm, mixing time 5 min). Then, nylon 6 was mixed with oleamide at a mass ratio of 2:100 in a high-speed mixer (mixing speed 3000 rpm, mixing time 5 min). The mixture was then extruded and granulated in a conventional twin-screw extruder, and finally injection molded to obtain the test sample. The crystallization temperature was determined according to the method in Example 1. T c and half-crystal time ( t 1 / 2 ), and the specific data is shown in Table 1.

[0024] Table 1 Test results of each embodiment and comparative example

[0025] According to the experimental results in Table 1, the crystallization performance of the nylon 6 dual-effect additive prepared in Examples 1-3 with the addition of this invention is higher than that of the comparative example. Among them, Example 1 with an addition amount of 2% is the best. Compared with pure nylon 6 in Comparative Example 1, this shows that the nylon 6 dual-effect additive synthesized in this invention has the effect of significantly improving the crystallization temperature and half-crystallization time of nylon 6. However, too much or too little nylon 6 dual-effect additive will have an adverse effect on the crystallization temperature and half-crystallization time of nylon 6.

[0026] The dual-effect additive for nylon 6 prepared in this invention is synthesized through a chemical reaction and can achieve both improved nucleation and lubrication of nylon 6. Comparative Examples 2-4, however, consisted only of single raw materials, intermediates, or simple mixtures of raw materials, without a complete chemical reaction, thus failing to fully realize the aforementioned dual-effect. Specifically, the oleamide added in Comparative Example 2 provides lubrication, significantly increasing the crystallization temperature and accelerating the crystallization rate of nylon 6. The 4-tert-butylbenzoyl chloride added in Comparative Example 3, being a liquid, has almost no effect on increasing the crystallization temperature or accelerating the crystallization rate. Comparative Example 4, which simultaneously added oleamide and 4-tert-butylbenzoyl chloride, only provides some lubrication due to the incomplete chemical reaction; therefore, its improvement effect is only better than that of Comparative Examples 3 and 4, which added single components. Although Comparative Example 2 is the optimal solution among the comparative examples, it still differs significantly from Example 1 due to the incomplete chemical reaction.

[0027] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the scope of the present invention.

Claims

1. A method for preparing a dual-effect nylon 6 additive, characterized in that, Its molecular structure is: The nylon 6 dual-effect additive was prepared as follows: 30 g of oleamide was dissolved in 100 mL of acetone, and 21 mL of 4-tert-butylbenzoyl chloride was added. The mixture was stirred at 40 °C for 18 h. After the reaction was completed, the mixture was washed with 200 mL of acetone until the pH of the system was 7. The product was then dried in an oven at 70 °C until constant weight to obtain the nylon 6 dual-effect additive.

2. The application of a dual-effect nylon 6 additive in nylon 6, characterized in that, Its molecular structure is: The amount of the nylon 6 dual-effect additive is 1-5% of nylon 6.

3. The application of a dual-effect nylon 6 additive according to claim 2 in nylon 6, characterized in that: The amount of the nylon 6 dual-effect additive is 2% of nylon 6.

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