A wear resistant, scratch resistant polyester fiber web and method of making the same

Abstract

This invention discloses a wear-resistant and scratch-resistant polyester fiber mesh and its preparation method, belonging to the technical field of polyester fiber materials. The polyester fiber mesh is prepared from polyester monofilaments through a weaving process. The polyester monofilaments are prepared from raw materials containing the following components: 100 parts by weight of polyethylene terephthalate (PET), and 0.3-1.0 parts by weight of a composite nucleating agent. The composite nucleating agent is composed of melamine cyanurate and sodium palmitate, wherein the weight ratio of melamine cyanurate to sodium palmitate is 10:2-3. This invention utilizes the layered structure of melamine cyanurate to anchor sodium palmitate molecules, effectively inhibiting the degradation of PET molecular chains caused by sodium palmitate, while simultaneously leveraging the synergistic nucleation effect of both, significantly improving the crystallization temperature, flexural modulus, wear resistance, and surface hardness of the polyester monofilaments. The polyester fiber mesh prepared by this invention has excellent wear and scratch resistance properties and can be widely used in paper forming mesh, industrial filter mesh, printing mesh, and other fields.

Description

Technical Field

[0001] This invention belongs to the technical field of polyester fiber materials, specifically relating to a wear-resistant and scratch-resistant polyester fiber web and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET) monofilaments are widely used in the manufacture of polyester fiber mesh products such as paper forming mesh, industrial filter mesh, and printing mesh due to their excellent chemical stability, high strength, and fatigue resistance. However, the rigid benzene ring structure in the PET molecular chain restricts the movement of the molecular chain, resulting in a slow crystallization rate, low crystallinity, and large spherulites. This defect not only affects processing efficiency (requiring high mold temperatures and long cooling cycles) but also makes the fiber mesh products prone to wear and scratches during use due to their coarse surface grains and loose structure, thus limiting their service life.

[0003] Improving the crystallization rate and refining the grain structure of PET are effective ways to improve its mechanical properties and wear resistance. Adding nucleating agents is currently one of the most important methods for controlling the crystallization behavior of PET. In existing technologies, sodium carboxylate nucleating agents (such as sodium palmitate and sodium stearate) function through a "chemical nucleation" mechanism—reacting with the PET molecular chains during high-temperature melting to form ion clusters. These ion clusters serve as efficient nucleation sites to promote crystallization. However, this reaction is often accompanied by the breakage of PET molecular chains, leading to a decrease in intrinsic viscosity and material toughness, and the improvement effect on wear resistance and scratch resistance is not significant.

[0004] Melamine cyanurate (MCA) is a crystalline complex formed by the reaction of melamine and cyanuric acid. MCA is primarily used as a halogen-free flame retardant in PET, but its unique layered structure and abundant hydrogen bonding sites also endow it with some nucleation potential. However, the effect of using MCA alone on increasing the crystallization rate of PET is limited.

[0005] In existing technologies, compound nucleating agents can achieve better nucleation effects than single nucleating agents through the synergistic effect between different nucleating agents. However, existing compound nucleating agent technologies are mostly aimed at injection molding applications of PET engineering plastics, and there has been no systematic research on improving the wear resistance and scratch resistance of PET fiber web products. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a wear-resistant and scratch-resistant polyester fiber web and its preparation method. This invention utilizes a specific ratio of melamine cyanurate and sodium palmitate as nucleating agents, leveraging their synergistic effect to significantly improve the wear-resistant and scratch-resistant properties of the polyester fiber web while maintaining or enhancing the crystallinity of PET, and effectively suppressing the molecular weight reduction problem caused by sodium carboxylate.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A wear-resistant and scratch-resistant polyester fiber mesh is prepared by a weaving process of polyester monofilaments. The polyester monofilaments are prepared from raw materials containing the following components: 100 parts by weight of polyethylene terephthalate (PET) and 0.3-1.0 parts by weight of a composite nucleating agent; the composite nucleating agent is composed of melamine cyanurate (MCA) and sodium palmitate, wherein the weight ratio of MCA to sodium palmitate is 10:2-3.

[0008] Preferably, the weight ratio of MCA to sodium palmitate is 10:2.5.

[0009] Preferably, the amount of the composite nucleating agent added is 0.4-0.7 parts by weight, more preferably 0.5 parts by weight.

[0010] Preferably, the intrinsic viscosity of the PET is 0.65-0.85 dL / g.

[0011] This invention also provides a method for preparing abrasion-resistant and scratch-resistant polyester fiber mesh, comprising the following steps: (1) Dry the PET slices at 110-150°C for 4-12 hours; (2) The dried PET chips are mixed with the composite nucleating agent according to the specified ratio, wherein the composite nucleating agent is composed of melamine cyanurate and sodium palmitate in a weight ratio of 10:2-3; (3) The mixture is fed into a twin-screw extruder and melt-extruded and granulated at 260-290°C to obtain modified PET masterbatch; (4) The modified PET masterbatch is melt-extruded through a spinning extruder and then extruded through a spinneret to form nascent filaments; (5) The nascent yarn is cooled, stretched in one stage, stretched in two stages and heat-set to obtain wear-resistant and scratch-resistant polyester monofilament; (6) The polyester monofilament is processed by weaving process to obtain wear-resistant and scratch-resistant polyester fiber mesh.

[0012] Preferably, in step (3), the screw speed of the twin-screw extruder is 100-300 rpm, and the temperature of each zone is set as follows: Zone 1 240-260°C, Zone 2 260-280°C, Zone 3 270-290°C, Zone 4 270-290°C, and the die head 260-280°C. Preferably, the spinning temperature in step (4) is 270-290°C; Preferably, in step (5), cooling is performed using a water bath at 20-50°C, the first stretching is performed in hot water at 70-100°C with a stretching ratio of 2-5 times, the second stretching is performed in hot air at 180-220°C with a stretching ratio of 1.5-3 times, and the heat setting temperature is 200-240°C.

[0013] Preferably, the polyester fiber mesh is a paper forming mesh, an industrial filter mesh, or a printing mesh.

[0014] The principle of this invention: Sodium palmitate, as an organic carboxylate nucleating agent, induces the ordered arrangement of PET molecular chains and promotes crystallization through an ion cluster mechanism. However, during high-temperature processing, it can trigger transesterification degradation of PET, leading to a decrease in intrinsic viscosity. Melamine cyanurate (MCA) has a layered crystal structure with abundant polar groups between the layers. When MCA and sodium palmitate coexist in PET melt, the polar groups on the surface of the MCA layered structure can form hydrogen bonds or ion-dipole interactions with the carboxylate anions of sodium palmitate, anchoring the sodium palmitate molecules to its surface. This anchoring effect restricts the free movement of sodium palmitate, reducing the probability of transesterification with PET molecular chains and thus inhibiting the decrease in molecular weight. Furthermore, it allows sodium palmitate to form high-density ion cluster nucleation sites on the MCA surface, synergistically enhancing the overall nucleation density with the heterogeneous nucleation of MCA itself. Simultaneously, the layered structure of MCA improves the dispersion uniformity of sodium palmitate in the PET matrix.

[0015] When the weight ratio of MCA to sodium palmitate is within the range of 10:2-3, the number of polar sites on the MCA surface and the number of sodium palmitate molecules are optimally matched, resulting in the most sufficient anchoring and dispersing effects, and both exhibit a synergistically enhanced nucleation effect. If the proportion of sodium palmitate is too low, chemical nucleation is insufficient; if the proportion is too high, the excess sodium palmitate exceeds the anchoring capacity of MCA, and the free sodium palmitate causes excessive degradation of PET, leading to a deterioration in performance.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention effectively inhibits the transesterification reaction between sodium palmitate and PET molecular chains by anchoring sodium palmitate molecules through the layered structure of MCA. This represents a technological breakthrough in suppressing degradation side reactions while leveraging the nucleation effect of carboxylate, overcoming a long-standing technical challenge in this field.

[0017] This invention utilizes the synergistic nucleation effect of MCA and sodium palmitate to significantly improve the crystallization temperature and crystallinity of PET, resulting in crystallization performance that is significantly superior to single nucleating agent systems. The composite nucleating agent system greatly refines the grain size of PET, providing a sound microstructure basis for improved mechanical properties and abrasion resistance. The polyester monofilament prepared by adding the composite nucleating agent of this invention exhibits excellent abrasion resistance and scratch resistance, with both abrasion resistance and surface hardness significantly superior to existing technologies.

[0018] Experimental tests have shown that all performance indicators reach their optimal values ​​only when the weight ratio of MCA to sodium palmitate is within the range of 10:2-3. Too low a ratio results in insufficient synergistic effect, while too high a ratio leads to excessive sodium palmitate causing degradation and performance deterioration. This "ratio window" effect fully demonstrates the non-obviousness and unexpected technical effects of the ratio range defined in this invention—the wear resistance of Example 1 (10:2.5) far exceeds the expectation of simply adding Comparative Example 3 (sodium palmitate alone) and Comparative Example 2 (MCA alone), proving a synergistic effect between the two.

[0019] The MCA and sodium palmitate used in this invention are both commercially available industrial raw materials, which are widely available and inexpensive. Furthermore, the processing technology is fully compatible with existing PET spinning and weaving processes, requiring no equipment modification and making it suitable for industrial application. Detailed Implementation

[0020] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] Raw material source: PET chips: CZ-318 type, Jiangsu Sanfangxiang Group Co., Ltd., intrinsic viscosity 0.75 dL / g; Melamine cyanurate (MCA): Industrial grade, purity ≥99%, commercially available; Sodium palmitate: analytical grade, Shanghai Maclean Biochemical Technology Co., Ltd.

[0022] Example 1 Preparation of composite nucleating agent: MCA and sodium palmitate were physically mixed evenly at a weight ratio of 10:2.5 to obtain composite nucleating agent CNA-1.

[0023] Preparation of polyester fiber web: (1) Dry the PET slices at 120°C for 8 hours; (2) Take 100 parts by weight of dried PET chips and mix them with 0.5 parts by weight of composite nucleating agent CNA-1 in a high-speed mixer until homogeneous; (3) The mixture is fed into a twin-screw extruder for melt extrusion granulation; the extruder is set at 250°C in zone 1, 265°C in zone 2, 280°C in zone 3, 280°C in zone 4, and 270°C at the die head, with the screw speed at 200 rpm, to obtain modified PET masterbatch; (4) Modified PET masterbatch is fed into a single-screw spinning extruder at a spinning temperature of 280°C and extruded through a spinneret to obtain nascent filaments; (5) The nascent filaments are cooled and shaped in a 35°C water bath; (6) After cooling, the nascent filament is placed in 90°C hot water for a first-stage stretching, with a stretching ratio of 3.5 times; (7) The first-stage stretched monofilament is subjected to a second-stage stretching under a hot air environment at 200°C, with a stretching ratio of 2.0 times; (8) The secondary drawn monofilament was heat-set under hot air at 220°C to obtain a wear-resistant and scratch-resistant polyester monofilament with a diameter of 0.20 mm; (9) Polyester monofilaments are warped and woven in a plain weave with a warp and weft density of 80×80 threads / cm to obtain a wear-resistant and scratch-resistant polyester fiber web.

[0024] Example 2 The difference between this embodiment and Example 1 is that the weight ratio of MCA to sodium palmitate is 10:2. The nucleating agent is CNA-2. All other operations are the same as in Example 1.

[0025] Example 3 The difference between this embodiment and Example 1 is that the weight ratio of MCA to sodium palmitate is 10:3. The nucleating agent is CNA-3. All other operations are the same as in Example 1.

[0026] Comparative Example 1 No nucleating agents were added. After drying the PET chips at 120°C for 8 hours, they were directly fed into a single-screw spinning extruder for spinning, with the remaining process conditions being the same as in Example 1.

[0027] Comparative Example 2 Only MCA was added as a nucleating agent, without sodium palmitate, at a dosage of 0.5 parts by weight. The remaining operations were the same as in Example 1.

[0028] Comparative Example 3 Sodium palmitate was added as a nucleating agent, without MCA, at a dosage of 0.5 parts by weight. The remaining operations were the same as in Example 1.

[0029] Comparative Example 4 The weight ratio of MCA to sodium palmitate is 10:1, and the total amount of composite nucleating agent added is 0.5 parts by weight. The remaining operations are the same as in Example 1.

[0030] Comparative Example 5 The weight ratio of MCA to sodium palmitate is 10:4, and the total amount of composite nucleating agent added is 0.5 parts by weight. The remaining operations are the same as in Example 1.

[0031] Comparative Example 6 The weight ratio of MCA to sodium palmitate is 10:5, and the total amount of composite nucleating agent added is 0.5 parts by weight. The remaining operations are the same as in Example 1.

[0032] The performance of the polyester monofilaments prepared in the examples and comparative examples was tested.

[0033] (1) Differential scanning calorimetry (DSC): A TA Q2000 DSC instrument was used under N2 protection. The sample was first heated to 280°C at 40°C / min and held for 3 min to eliminate thermal history. Then, it was cooled to 80°C at 20°C / min. The crystallization temperature (Tc) and crystallization enthalpy (ΔHc) were recorded. The crystallinity was calculated according to formula (2): Xc = ΔHm / (ΔHm0 × ω) × 100%, where ΔHm0 was taken as 139 J / g.

[0034] (2) Intrinsic viscosity: The viscosity was tested according to ASTM D4603 standard using an Ubbelohde viscometer with phenol / tetrachloroethane (60:40, by weight) as the solvent.

[0035] (3) Bending modulus: Tested using a universal testing machine according to ASTM D790 standard.

[0036] (4) Abrasion resistance test: A yarn abrasion tester was used with a weight of 20g to record the number of frictions at the point of breakage.

[0037] (5) Scratch resistance test: The pencil hardness method is used and the test is conducted according to GB / T 6739 standard.

[0038] (6) Polarizing microscope (POM): An Olympus BX53M POM was used. The sample was melted at 280°C for 3 min and then rapidly cooled to 220°C for isothermal crystallization to observe the spherulite morphology.

[0039] (7) X-ray diffraction (XRD): Bruker D8 Advance type XRD, Cu Kα rays, 2θ=10-40°, and grain size was calculated according to Scherrer formula.

[0040] Table 1. Comparison of properties of polyester monofilaments prepared in each example and comparative example.

[0041] As shown in Table 1, Comparative Example 1 is a blank PET, and its properties are at the baseline level. When MCA is added alone in Comparative Example 2, the crystallization temperature and mechanical properties are only slightly improved. When sodium palmitate is added alone in Comparative Example 3, although the crystallization temperature is increased, the intrinsic viscosity decreases significantly, indicating that sodium palmitate causes molecular chain degradation.

[0042] In comparison, the performance of Examples 1-3 (MCA:sodium palmitate = 10:2-3) was significantly better than that of the comparative examples: the crystallization temperature and crystallinity were greatly improved, and the intrinsic viscosity not only did not decrease but was slightly increased, indicating that MCA effectively inhibited the degradation side reaction of sodium palmitate; the flexural modulus and abrasion resistance were significantly better than those of blank PET and single nucleating agent system, the pencil hardness was increased by two levels, and the grain size was significantly refined.

[0043] Comparative Examples 4-6 show that when the ratio of MCA to sodium palmitate exceeds 10:2-3, all properties are significantly inferior to those of Examples 1-3. In particular, in Comparative Examples 5-6, when the proportion of sodium palmitate is too high, the intrinsic viscosity decreases dramatically, proving that excessive sodium palmitate exceeds the anchoring capacity of MCA, causing severe degradation of PET, and consequently deteriorating its abrasion resistance and mechanical properties. These results indicate that MCA and sodium palmitate can only fully exert their dual effects of synergistic nucleation and degradation inhibition within a specific ratio range of 10:2-3.

[0044] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A wear-resistant and scratch-resistant polyester fiber mesh, characterized in that: The polyester fiber web is made from polyester monofilaments through a weaving process. The polyester monofilaments are made from raw materials containing the following components: 100 parts by weight of polyethylene terephthalate (PET) and 0.3-1.0 parts by weight of a composite nucleating agent. The composite nucleating agent is composed of melamine cyanurate and sodium palmitate, wherein the weight ratio of melamine cyanurate to sodium palmitate is 10:2-3.

2. The wear-resistant and scratch-resistant polyester fiber mesh according to claim 1, characterized in that: The weight ratio of melamine cyanurate to sodium palmitate is 10:2.

5.

3. The wear-resistant and scratch-resistant polyester fiber mesh according to claim 1, characterized in that: The amount of the composite nucleating agent added is 0.4-0.7 parts by weight.

4. The wear-resistant and scratch-resistant polyester fiber mesh according to claim 1, characterized in that: The intrinsic viscosity of the PET is 0.65-0.85 dL / g.

5. A method for preparing a wear-resistant and scratch-resistant polyester fiber web, characterized in that... Includes the following steps: (1) Dry the PET slices at 110-150°C for 4-12 hours; (2) The dried PET chips are mixed evenly with the composite nucleating agent according to the specified ratio. The composite nucleating agent is composed of melamine cyanurate and sodium palmitate in a weight ratio of 10:2-3. (3) The mixture is fed into a twin-screw extruder and melt-extruded and granulated at 260-290°C to obtain modified PET masterbatch; (4) The modified PET masterbatch is melt-extruded through a spinning extruder and then extruded through a spinneret to form nascent filaments; (5) The nascent yarn is cooled, stretched in one stage, stretched in two stages and heat-set to obtain wear-resistant and scratch-resistant polyester monofilament; (6) The polyester monofilament is processed by weaving process to obtain wear-resistant and scratch-resistant polyester fiber mesh.

6. The preparation method according to claim 5, characterized in that: In step (4), the spinning temperature is 270-290°C.

7. The preparation method according to claim 5, characterized in that: In step (5), cooling is performed using a water bath at 20-50°C; the first stretching is performed in hot water at 70-100°C with a stretching ratio of 2-5 times; the second stretching is performed in hot air at 180-220°C with a stretching ratio of 1.5-3 times; and the heat setting temperature is 200-240°C.

8. The application of the wear-resistant and scratch-resistant polyester fiber mesh according to any one of claims 1-4 in paper forming mesh, industrial filter mesh or printing mesh.

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