High-strength low-shrinkage polyamide yarn and its preparation process

Abstract

The application relates to the technical field of nylon filament, and discloses high-strength low-shrinkage nylon filament and a preparation process thereof. Nylon resin and glutamine polyvinyl alcohol are mixed, melt spinning is carried out in a melt spinning machine, then the fiber is stretched in a heat stretching device, and the high-strength low-shrinkage nylon filament is obtained. After polyvinyl alcohol introduces a large number of amide bonds, the compatibility with the nylon polyamide molecular chain is obviously improved, strong hydrogen bond and other interaction forces are formed between the two, the cohesion of the fiber is improved, the nylon filament has higher structural stability, the thermal shrinkage rate is smaller, the breaking strength and the breaking elongation are larger, and the mechanical property is better. Moreover, polyvinyl alcohol has good hydrophilicity, the hydrophilic carboxyl and amide bond are further introduced, and the nylon filament has higher moisture regain and hygroscopicity.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nylon filament, in particular to a high-strength and low-shrinkage nylon filament and a preparation process thereof. BACKGROUND

[0002] Nylon filament is a chemical synthetic fiber mainly made of nylon resin spinning, which has good wear resistance, air permeability, chemical corrosion resistance and other properties, and is widely used in clothing, rope filter, sports equipment and other aspects. In order to improve the shrinkage resistance, mechanics, moisture absorption and other properties of nylon filament, it is usually necessary to modify it. Polyvinyl alcohol and its fibers have high hydrophilicity, good biocompatibility and high mechanical strength, and are widely used. The fiber made by blending spinning of polyvinyl alcohol, nylon, polyester, collagen and other materials has better mechanical properties, moisture absorption and other properties. However, the compatibility of polyvinyl alcohol and nylon resin is poor, which will affect the performance of the blended spinning fiber. The patent with publication number CN116288787B discloses a preparation method of a nylon large biological fiber containing bioactive components. Polyvinyl alcohol is grafted and modified, then cross-linked and polymerized with epichlorohydrin to form a network structure, and is granulated and spun with nylon chips to obtain nylon fiber with good antibacterial, mechanical and other properties. However, the patent does not improve the heat shrinkage resistance, moisture absorption and other properties of the nylon fiber. SUMMARY

[0003] In view of the shortcomings of the prior art, the present application provides a high-strength and low-shrinkage nylon filament and a preparation process thereof, which solves the problems of low strength and poor hydrophilicity of the nylon filament, and improves the heat shrinkage resistance of the nylon filament.

[0004] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: a high-strength and low-shrinkage nylon filament and a preparation process thereof, the nylon filament comprising 70-90 parts by weight of nylon resin and 10-30 parts by weight of glutamine polyvinyl alcohol.

[0005] The preparation process of the nylon filament is as follows:

[0006] (1) polyvinyl alcohol is added to dimethyl sulfoxide, heated and stirred, then N-alkyl maleic acid amide with structural formula , 4-dimethylaminopyridine and dicyclohexyl carbodiimide are added, stirred and reacted, the solution is added to saturated sodium chloride solution, the precipitate is washed with saturated sodium chloride solution after filtration, and dried to obtain polyvinyl alcohol intermediate.

[0007] (2) polyvinyl alcohol intermediate and glutamine are added to ethanol aqueous solution, stirred and reacted, the solution is added to saturated sodium chloride solution, the precipitate is washed with saturated sodium chloride solution after filtration, and dried to obtain glutamine polyvinyl alcohol. The preparation reaction formula is as follows:

[0008] .

[0009] (3) mixing nylon resin and glutamine polyvinyl alcohol, melt spinning in a melt spinning machine, then drawing the fiber in a heat drawing device to obtain high-strength low-shrinkage nylon yarn.

[0010] Further, the ratio of polyvinyl alcohol, N-alkyl maleic acid amide, 4-dimethylaminopyridine and dicyclohexyl carbodiimide in (1) is 100g: (40-150) mmol: (48-180) mmol: (8-30) mmol.

[0011] Further, the reaction in (1) is carried out at 20-35℃ for 18-36h.

[0012] Further, the volume fraction of the ethanol aqueous solution in (2) is 60-80%.

[0013] Further, the ratio of polyvinyl alcohol intermediate and glutamine in (2) is 100g: (50-190) mmol.

[0014] Further, the reaction in (2) is carried out at 35-50℃ for 12-24h.

[0015] Further, the temperature during spinning in (3) is 240-250℃.

[0016] Further, the temperature during drawing in (3) is 100-120℃, and the draw ratio is 3-4 times.

[0017] The application has the beneficial technical effects that: in the catalytic system of 4-dimethylaminopyridine and dicyclohexyl carbodiimide, the carboxyl group of N-alkyl maleic acid amide is esterified with polyvinyl alcohol, then the introduced alkenyl group is subjected to Michael addition reaction with the amino group of glutamine, thereby introducing a large number of amide bonds and carboxyl groups into polyvinyl alcohol, and then melt spinning with nylon resin to obtain high-strength low-shrinkage nylon yarn. After introducing a large number of amide bonds into polyvinyl alcohol, the compatibility with nylon polyamide molecular chain is obviously improved, strong hydrogen bond and other interaction forces are formed between them, the cohesion of the fiber is improved, the nylon yarn has higher structural stability, the thermal shrinkage rate is smaller, and the breaking strength and elongation at break are larger, and the mechanical properties are better. At the same time, polyvinyl alcohol itself has good hydrophilicity, and the introduction of hydrophilic carboxyl and amide bonds further makes the nylon yarn have higher moisture regain and moisture absorption. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. Embodiment

[0019] (1) N-alkyl maleic acid amide ((E)-4-(butylamino)-4-oxobut-2-enoic acid) was prepared according to the method of journal literature Chemical Communications, 2015, vol. 51, #73, p. 13906-13909, “Transfer hydrogenation promoted by N-heterocyclic carbene and water”, and the structural formula is as follows: (same below).

[0020] (2) 200 g of polyvinyl alcohol was added to 4 L of dimethyl sulfoxide, and after heating and stirring, 80 mmol of N-alkyl maleic acid amide, 96 mmol of 4-dimethylaminopyridine, and 24 mmol of dicyclohexyl carbodiimide were added, and the solution was stirred at 35°C for 18 h. The solution was added to a saturated sodium chloride solution, and the precipitate was washed with a saturated sodium chloride solution after filtration, and dried to obtain a polyvinyl alcohol intermediate.

[0021] (3) 300 g of the polyvinyl alcohol intermediate and 150 mmol of glutamine (CAS No. 56-85-9) were added to 5 L of 60% ethanol aqueous solution, heated to 35°C, and stirred for 18 h. The solution was added to a saturated sodium chloride solution, and the precipitate was washed with a saturated sodium chloride solution after filtration, and dried to obtain glutamine-modified polyvinyl alcohol.

[0022] (4) 900 g of nylon resin (model PA6 M2500I, same below) and 100 g of glutamine-modified polyvinyl alcohol (model 1788, same below) were mixed, and melt spinning was performed in a melt spinning machine at a spinning temperature of 250°C. Then the fiber was drawn in a heat drawing device at a drawing temperature of 110°C and a drawing ratio of 4 times to obtain high-strength low-shrinkage nylon silk. Embodiment

[0023] (1) To 5 L dimethyl sulfoxide, 200 g of polyvinyl alcohol was added, after heating and stirring, 250 mmol of N-alkyl maleic acid amide, 300 mmol of 4-dimethylaminopyridine, 44 mmol of dicyclohexyl carbodiimide were added, and stirred at 20 °C for 36 h. The solution was added to saturated sodium chloride solution, and the precipitate was washed with saturated sodium chloride solution after filtration, and dried to obtain a polyvinyl alcohol intermediate.

[0024] (2) To 5.5 L of 80% ethanol aqueous solution, 300 g of polyvinyl alcohol intermediate, 380 mmol of glutamine were added, heated to 40 °C, and stirred for 24 h. The solution was added to saturated sodium chloride solution, and the precipitate was washed with saturated sodium chloride solution after filtration, and dried to obtain glutaminated polyvinyl alcohol.

[0025] (3) 800 g of nylon resin and 200 g of glutaminated polyvinyl alcohol were mixed, and melt spinning was performed in a melt spinning machine at a spinning temperature of 240 °C, and then the fiber was drawn in a hot drawing device at a drawing temperature of 120 °C with a draw ratio of 3 times to obtain a high-strength low-shrinkage nylon filament. Example

[0026] (1) To 5 L dimethyl sulfoxide, 200 g of polyvinyl alcohol was added, after heating and stirring, 300 mmol of N-alkyl maleic acid amide, 360 mmol of 4-dimethylaminopyridine, 60 mmol of dicyclohexyl carbodiimide were added, and stirred at 25 °C for 36 h. The solution was added to saturated sodium chloride solution, and the precipitate was washed with saturated sodium chloride solution after filtration, and dried to obtain a polyvinyl alcohol intermediate.

[0027] (2) To 6 L of 80% ethanol aqueous solution, 300 g of polyvinyl alcohol intermediate, 570 mmol of glutamine were added, heated to 50 °C, and stirred for 12 h. The solution was added to saturated sodium chloride solution, and the precipitate was washed with saturated sodium chloride solution after filtration, and dried to obtain glutaminated polyvinyl alcohol.

[0028] (3) 700 g of nylon resin and 300 g of glutaminated polyvinyl alcohol were mixed, and melt spinning was performed in a melt spinning machine at a spinning temperature of 240 °C, and then the fiber was drawn in a hot drawing device at a drawing temperature of 100 °C with a draw ratio of 4 times to obtain a high-strength low-shrinkage nylon filament.

[0029] Comparative Example 1, the difference between this comparative example and Example 1 is that glutaminated polyvinyl alcohol is not added.

[0030] (1) 900 g of nylon resin was melt spun in a melt spinning machine at a spinning temperature of 250 °C, and then the fiber was drawn in a hot drawing device at a drawing temperature of 110 °C with a draw ratio of 4 times to obtain a nylon filament.

[0031] Comparative Example 2, the difference between this comparative example and Example 1 is that polyvinyl alcohol is used instead of glutaminated polyvinyl alcohol.

[0032] (1) 900 g of nylon resin and 100 g of polyvinyl alcohol were mixed, melt spinning was performed in a melt spinning machine, the spinning temperature was 250°C, then the fiber was drawn in a heat drawing device, the drawing temperature was 110°C, the draw ratio was 4 times, to obtain a nylon filament.

[0033] Comparative Example 3, the difference between this comparative example and Example 1 is that monoethyl fumarate (CAS No. 2459-05-4) is used instead of N-alkyl maleic acid amide.

[0034] (1) 200 g of polyvinyl alcohol was added to 4 L of dimethyl sulfoxide, after heating and stirring, 80 mmol of monoethyl fumarate, 96 mmol of 4-dimethylaminopyridine, and 24 mmol of dicyclohexyl carbodiimide were added, and the solution was stirred at 35°C for 18 h, then the solution was added to a saturated sodium chloride solution, the precipitate was washed with a saturated sodium chloride solution after filtration, and dried to obtain a polyvinyl alcohol intermediate.

[0035] (2) 300 g of the polyvinyl alcohol intermediate and 150 mmol of glutamine were added to 5 L of a 60% ethanol aqueous solution, heated to 35°C, and stirred for 18 h, then the solution was added to a saturated sodium chloride solution, the precipitate was washed with a saturated sodium chloride solution after filtration, and dried to obtain glutaminated polyvinyl alcohol.

[0036] (3) 900 g of nylon resin and 100 g of glutaminated polyvinyl alcohol were mixed, melt spinning was performed in a melt spinning machine, the spinning temperature was 250°C, then the fiber was drawn in a heat drawing device, the drawing temperature was 110°C, the draw ratio was 4 times, to obtain a nylon filament.

[0037] Comparative Example 4, the difference between this comparative example and Example 1 is that glycine (CAS No. 56-40-6) is used instead of glutamine.

[0038] (1) 200 g of polyvinyl alcohol was added to 4 L of dimethyl sulfoxide, after heating and stirring, 80 mmol of N-alkyl maleic acid amide, 96 mmol of 4-dimethylaminopyridine, and 24 mmol of dicyclohexyl carbodiimide were added, and the solution was stirred at 35°C for 18 h, then the solution was added to a saturated sodium chloride solution, the precipitate was washed with a saturated sodium chloride solution after filtration, and dried to obtain a polyvinyl alcohol intermediate.

[0039] (2) 300 g of polyvinyl alcohol intermediate and 150 mmol of glycine were added to a 5 L 60% ethanol aqueous solution, heated to 35°C, and stirred for 18 h. The solution was added to a saturated sodium chloride solution, the precipitate was filtered and washed with a saturated sodium chloride solution, and dried to obtain glycine-modified polyvinyl alcohol.

[0040] (3) 900 g of nylon resin and 100 g of glycine-modified polyvinyl alcohol were mixed and melt spun in a melt spinning machine at a spinning temperature of 250°C. The fiber was then drawn in a heat drawing device at a drawing temperature of 110°C and a draw ratio of 4 times to obtain a high-strength low-shrinkage nylon filament.

[0041] The nylon filament was straightened, the length was measured (denoted as L0), placed in an oven at 120°C for 24 h, cooled to room temperature, and then the length (L) was measured. The heat shrinkage rate W was calculated as W = (L0-L) / L0 x 100%. Each group of samples was tested 10 times, and the average value was taken.

[0042] The tensile properties of the nylon filament were tested according to standard GB / T 14337-2022.

[0043] The moisture regain was tested according to standard GB / T 6503-2017.

[0044] Table 1 Performance test of nylon filament

[0045]

[0046] The heat shrinkage rate of the nylon filament of Comparative Example 1 was large, and the elongation at break and moisture regain were low, and the mechanical properties and moisture absorption properties were poor. In Examples 1-3, N-alkyl maleic acid amide containing amide bonds and glutamine containing amide bonds and carboxyl groups were used to react with polyvinyl alcohol, a large number of amide bonds were introduced into polyvinyl alcohol, and after blending and spinning, the compatibility of polyvinyl alcohol containing amide bonds with nylon polyamide molecular chains was significantly improved, strong hydrogen bonding and other interaction forces were formed between them, the cohesion of the fiber was improved, the nylon filament had higher structural stability, the heat shrinkage rate was smaller, and the breaking strength and elongation at break were larger, and the mechanical properties were better. At the same time, polyvinyl alcohol itself has good hydrophilicity, and the introduction of hydrophilic carboxyl and amide bonds further improves the moisture regain and moisture absorption of the nylon filament.

[0047] Comparative Example 2 blended and spun nylon resin and polyvinyl alcohol, and the compatibility between the two was poor, resulting in low breaking strength and elongation at break of the nylon filament, poor mechanical properties, and the polyvinyl alcohol did not contain hydrophilic groups such as carboxyl groups, and the moisture regain was slightly lower than that of Example 1.

[0048] The monoethyl fumarate of Comparative Example 3 does not contain an amide bond, and the polyvinyl alcohol prepared has a low amide bond content, and has a lower compatibility with the molecular chain of the nylon polyamide than Example 1, resulting in a poor structural stability of the nylon filament, a large thermal shrinkage, and a lower breaking strength and elongation at break than Example 1, and a slightly lower moisture regain than Example 1.

[0049] The glycine of Comparative Example 4 does not contain an amide bond, and the polyvinyl alcohol prepared has a low amide bond content, and has a lower compatibility with the molecular chain of the nylon polyamide than Example 1, resulting in a poor structural stability of the nylon filament, a large thermal shrinkage, and a lower breaking strength and elongation at break than Example 1, and a slightly lower moisture regain than Example 1.

Claims

1. A high-strength low-shrinkage nylon filament, characterized by comprising: The high-strength low-shrinkage nylon filament comprises 70-90 parts by weight of nylon resin and 10-30 parts by weight of glutaminated polyvinyl alcohol. The preparation process of the glutaminated polyvinyl alcohol is as follows: S1, polyvinyl alcohol is added to dimethyl sulfoxide, after heating and stirring, N-alkyl maleic acid amide, 4-dimethylaminopyridine and dicyclohexyl carbodiimide are added, and the solution is added to a saturated sodium chloride solution after stirring and reaction, and the precipitate is washed with a saturated sodium chloride solution after filtration, and dried to obtain a polyvinyl alcohol intermediate; The N-alkyl maleic acid amide has a structural formula of , a is any integer from 2 to 8; S2, polyvinyl alcohol intermediate and glutamine are added to an aqueous ethanol solution, and the solution is added to a saturated sodium chloride solution after stirring and reaction, and the precipitate is washed with a saturated sodium chloride solution after filtration, and dried to obtain glutaminated polyvinyl alcohol.

2. The high-strength low-shrinkage nylon filament according to claim 1, wherein, The ratio of polyvinyl alcohol, N-alkyl maleic acid amide, 4-dimethylaminopyridine and dicyclohexyl carbodiimide in S1 is 100g: (40-150) mmol: (48-180) mmol: (8-30) mmol.

3. The high-strength low-shrinkage nylon yam of claim 1, wherein The reaction in S1 is carried out at 20-35℃ for 18-36h.

4. The high-strength low-shrinkage nylon yam of claim 1, wherein The volume fraction of the aqueous ethanol solution in S2 is 60-80%.

5. The high-strength low-shrinkage nylon yam of claim 1, wherein The ratio of polyvinyl alcohol intermediate and glutamine in S2 is 100g: (50-190) mmol.

6. The high-strength low-shrinkage nylon yam of claim 1, wherein The reaction in S2 is carried out at 35-50℃ for 12-24h.

7. A process for the production of high-strength low-shrinkage polyamide yarn as claimed in any one of claims 1 to 6, characterized in that, The preparation process comprises: mixing nylon resin and glutaminated polyvinyl alcohol, melt spinning in a melt spinning machine, and then drawing the fiber in a heat drawing device to obtain a high-strength low-shrinkage nylon filament.

8. The process for the preparation of high-strength low-shrinkage nylon filament as claimed in claim 7, wherein, The temperature during spinning is 240-250℃.

9. The process for the preparation of high-strength low-shrinkage nylon filament as claimed in claim 7, wherein, The temperature during drawing is 100-120℃, and the draw ratio is 3-4 times.

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