An antigenic fibrillating polyester monofilament and a method for its preparation

Abstract

The application belongs to the technical field of polyester monofilament preparation, and particularly relates to an anti-fibrillation polyester monofilament and a preparation method thereof. The anti-fibrillation polyester monofilament is prepared by means of ultraviolet crosslinking post-treatment of the polyester monofilament on the basis of a conventional preparation process. The prepared polyester monofilament has excellent anti-fibrillation capacity by increasing crosslinking sites to improve the crystallinity of the fiber skin layer and to improve the interaction force between the original fiber molecular chains, the anti-fibrillation capacity is increased by more than 500%, and the mechanical properties are not obviously affected (the mechanical property retention rate is more than 90%), so the polyester monofilament has a wide market application prospect. In addition, the ultraviolet crosslinking post-treatment method has the advantages of small capital investment, safe and simple operation, high speed, little pollution to the environment, and small damage to the mechanical properties of the polyester monofilament, and is suitable for industrialized mass production.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of polyester monofilament preparation, and particularly relates to an anti-fibrillation polyester monofilament and a preparation method thereof. In particular, the present application provides a method for improving the anti-fibrillation capability of polyester monofilament and retaining the mechanical properties by performing ultraviolet crosslinking post-processing on the polyester monofilament. BACKGROUND

[0002] With the continuous development of the field of electronic circuit printing, the natural fibers such as silk used in the past, which are high in price and low in performance, have been unable to meet the demand for high-precision printing today. The silk screen required to achieve high-resolution printing should have excellent wear resistance, resilience, dimensional stability and other properties, and the monofilament of the woven silk screen should also have the characteristics of high strength, high modulus and fine fineness. In recent years, silk screens woven from synthetic fibers such as polyester and nylon, which are reasonable in cost and stable in performance, have been favored. Compared with nylon silk screens, polyester monofilament woven silk screens have better heat resistance and stability, smaller changes after absorbing moisture, lower prices and other advantages, and are widely used.

[0003] However, polyester monofilament used for weaving printing silk screens inevitably appears fibrillation phenomenon during production and use. The reason is that the thermal conductivity of high polymers is poor, and the radial temperature difference of the fiber caused by side blowing, heat stretching, heat setting and other spinning process links affects the unevenness of the melt viscosity, forms a radial viscosity gradient, affects the distribution of the radial tension of the fiber, and causes the fiber skin-core structure to be produced. Due to the high orientation degree of the skin layer along the fiber axis, the skin layer is easily damaged by stress concentration after mechanical friction, splits along the axial direction, and causes the fiber to appear fibrillation phenomenon. Silk screen printing uses silk screen as a plate base. Due to the high mesh requirement of the silk screen, polyester monofilament needs to be woven at high density, and the original silk will be repeatedly rubbed during the process of weaving into a printing silk screen, which will cause fibrillation, and further affect the quality of the entire silk screen, resulting in defects when passing through the photoreproduction electronic circuit, which is contrary to the requirement of high precision printing. Unfortunately, the fibrillation problem is easily ignored in other application scenarios of polyester monofilament, which has not been widely concerned and solved.

[0004] At present, for the problem of polyester monofilament fibrillation, some effective solutions have been explored under the previous scholars' efforts. The patent of polyester monofilament for screen printing reported that the skin-core composite polyester monofilament with conventional polyester as the core layer and polyalkylene oxide copolyester as the skin layer was used to inhibit the occurrence of monofilament surface scumming (fibrillation) phenomenon. However, the requirements of bicomponent composite monofilament for production process and production equipment are higher than those of monocomponent monofilament, which is not superior in cost, and the uniformity and stability of monofilament skin-core structure are difficult to guarantee. In the research literature "Enzymatic modification of polyester", the surface of polyester was modified by serine esterase, the polymer main chain was broken by hydrolyzing ester bond, and the soluble polymer fragments were shed, which could significantly reduce the polyester fibrillation and hairiness phenomenon. However, its hydrolysis efficiency is low, the treatment conditions are harsh and difficult to control, and the breaking strength and breaking elongation of the fiber after enzyme treatment are significantly reduced, so it is not suitable for the preparation of industrial polyester monofilament. In addition, since Lyocell fiber also has the typical skin-core structure characteristics of easy fibrillation, it has been widely studied in anti-fibrillation, which can provide ideas and insights for polyester monofilament anti-fibrillation to some extent. In the literature "Lyocell fiber defibrillation method", it is indicated that alkali treatment of fiber with sodium hydroxide or tetramethylammonium hydroxide can cause plasticization of Lyocell fiber, which can reduce the fibrillation tendency of the fiber by at least about 40%. In addition, the fiber can also be crosslinked. In the literature "Influence of crosslinking treatment on anti-fibrillation performance of Lyocell fiber", the nascent fiber obtained after water washing bath was crosslinked with a multi-functional crosslinking agent. The base fiber and base fiber aggregation bundle size were significantly reduced and the content was increased, the anti-fibrillation ability was significantly higher than that without crosslinking treatment, and the mechanical properties were not significantly affected. The invention patent of a method for reducing the fibrillation tendency of Lyocell cellulose fiber (CN104005225A) also mentioned that the crosslinking post-treatment with C2-C6 dialdehyde crosslinking agent, metal salt or organic acid catalyst and surfactant can effectively reduce the fibrillation tendency of Lyocell cellulose fiber.

[0005] However, the production of Lyocell fiber is a physical process of dissolving cellulose in NMMO (N-methylmorpholine-N-oxide) organic solvent and then precipitating, and a dry-jet wet spinning process is adopted. In addition, the molecular chains of Lyocell fiber are connected to each other through a large number of hydrogen bonds, which causes water molecules to easily enter the interior of the fiber in a wet state environment, destroy the lateral binding force between the molecules, and cause the Lyocell fiber to be almost a core layer with a usually thin skin layer, and the core layer is composed of highly crystalline, oriented giant fibrils and amorphous regions, and fibrillation usually occurs between the fibrils in the core layer. Therefore, a wet-state crosslinking method is usually adopted to make the crosslinking agent penetrate into the interior (core layer) of the fiber after swelling, form chemical bonds between the crosslinking agent molecules and the hydroxyl groups on the Lyocell fiber, and achieve the effect of resisting fibrillation by increasing the interaction force between the fibrils. In contrast, the polyester molecular chains are connected through ester bonds, and the polyester filaments obtained after melt spinning have relatively uniform crystalline and amorphous regions and strong interfacial bonding force, the interaction force between the molecular chains in the core layer is strong, and fibrillation mainly occurs in the skin layer with high crystallinity and orientation. In addition, in most common crosslinking cases, water usually tends to have an adverse effect on crosslinking. In summary, due to the significant differences in chemical structure and production process between Lyocell fiber and polyester fiber, the above crosslinking method of Lyocell fiber cannot be applied to polyester filaments.

[0006] Therefore, it is of great significance to realize high-precision printing in the high-end printing industry to invent a polyester filament with effective anti-fibrillation, excellent mechanical properties and low cost. SUMMARY

[0007] The purpose of the present application is to overcome the shortcomings of the prior art of polyester filaments, and to provide an anti-fibrillation polyester filament and a preparation method thereof, in particular to a method for preparing an anti-fibrillation polyester filament by first preparing a polyester filament with excellent mechanical properties by a melt spinning method, and then treating the spun filament with a photo-crosslinking agent and a hydrogen-abstracting type photo-initiator after drawing, and finally obtaining an anti-fibrillation polyester filament and a preparation method thereof after heat treatment and ultraviolet crosslinking modification. The anti-fibrillation polyester filament described in the present application is treated by ultraviolet crosslinking, and the ultraviolet crosslinking treatment is performed by using a photo-crosslinking agent and a photo-initiator to modify the polyester filament by ultraviolet crosslinking before winding, which can effectively improve the structural differences caused in the spinning process, improve the anti-fibrillation ability of the polyester filament while maintaining the mechanical properties, and meet the high-quality requirements of the high-end printing industry for printing screens.

[0008] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is:

[0009] One of the purposes of the present application is to provide a preparation method of anti-fibrillation polyester monofilament, which is based on the conventional preparation process, and the drawn polyester monofilament is subjected to post-treatment of ultraviolet crosslinking to prepare the anti-fibrillation polyester monofilament. The ultraviolet crosslinking treatment enables the polyester monofilament to be crosslinked and modified, and the prepared polyester monofilament has stable and persistent anti-fibrillation ability, and the mechanical properties are not affected.

[0010] Preferably, the ultraviolet crosslinking treatment comprises the following steps:

[0011] (1) The polyester monofilament prepared after drawing and heat setting is immersed in a solution containing a crosslinking agent;

[0012] (2) The immersed polyester monofilament is subjected to heat treatment;

[0013] (3) The polyester monofilament after heat treatment is subjected to an ultraviolet crosslinking step to complete the ultraviolet crosslinking treatment.

[0014] Preferably, in the solution containing a crosslinking agent in step (1), the concentration of the crosslinking agent is 0.5-2 wt%; more preferably, the crosslinking agent is a photo-crosslinking agent selected from at least one of triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), pentaerythritol triallyl (PETA), and glycidyl methacrylate (GMA).

[0015] Preferably, the solution containing a crosslinking agent in step (1) further contains a photoinitiator, and the concentration of the photoinitiator in the solution is 0.25-1 wt%; more preferably, the photoinitiator is a hydrogen abstraction type initiator, and more preferably selected from at least one of benzophenone (BP), 4-chlorobenzophenone (4-CBP), thioxanthone (TX), and isopropyl thioxanthone (ITX). The presence of the photoinitiator enables the crosslinking reaction to proceed more quickly.

[0016] Preferably, in the solution containing a crosslinking agent in step (1), the solvent is at least one of ethyl acetate, acetone, tetrahydrofuran, and dichloromethane.

[0017] More preferably, the crosslinking agent is triallyl isocyanurate (TAIC), and the photoinitiator is benzophenone (BP).

[0018] More preferably, the solution containing a crosslinking agent in step (1) is a mixed solution containing 0.5-2 wt% of the crosslinking agent and 0.25-1 wt% of the photoinitiator. The combined use of the photo-crosslinking agent and the photoinitiator enables the initiation system to quickly complete the crosslinking reaction in the initial reaction stage, effectively improving the rate and depth of ultraviolet photo-crosslinking.

[0019] Preferably, in step (1), the immersion time is 20-30 s, and the subsequent heat treatment and ultraviolet crosslinking steps are performed after the immersion.

[0020] Preferably, the heat treatment in step (2) is performed at a temperature of 70-90°C for a time of not less than 5 minutes, more preferably 5-10 minutes. The heat treatment is preferably performed under hot air to remove the solvent in the photo-crosslinking system. The heat treatment prevents the residual ethyl acetate solvent from interfering with the photo-crosslinking reaction and enables the photo-crosslinking agent and the photo-initiator to be firmly and uniformly attached to the surface of the fiber. At the same time, the crosslinking agent molecules are more easily diffused into the skin layer of the fiber through the micropores on the surface of the monofilament by more intense molecular thermal motion, and the concentration and activity of the photo-crosslinking agent are increased, so that the photo-crosslinking agent reacts more intensively with the active sites on the fiber, effectively improving the efficiency of the subsequent ultraviolet photo-crosslinking treatment. If the heat treatment temperature is too high, the photo-crosslinking agent and the photo-initiator will volatilize, affecting the subsequent photo-crosslinking effect, and also causing the oriented polyester molecular chains to be disoriented and degraded, resulting in a decrease in mechanical properties. If the heat treatment time is too short, the undried composite solution containing the photo-crosslinking agent and the initiator on the fiber will easily flow away or migrate, making it difficult to ensure the uniformity of the photo-crosslinking reaction, and the residual solvent may also affect the photo-crosslinking effect. A long heat treatment time will also cause the volatilization of the crosslinking agent / initiator and the initiation of unnecessary side reactions, reducing the crosslinking effect, and also causing unnecessary cost consumption. Similarly, if a thermal crosslinking method is used to bond and crosslink the crosslinking agent and the polyester fiber, for example, the DCP thermal crosslinking temperature range is between 150-200°C, and the crosslinking requires several hours. The disorientation and thermal degradation caused by high temperature will directly affect the strength, toughness and dimensional stability of the fiber, and the process is time-consuming and costly.

[0021] Preferably, the ultraviolet crosslinking step in step (3) is performed using ultraviolet light irradiation, and the wavelength of the ultraviolet light is in the range of 280-400 nm.

[0022] Preferably, the ultraviolet crosslinking temperature is 55-65°C, and the treatment time is 120-150 seconds. The ultraviolet crosslinking temperature is used to increase the rate of the ultraviolet crosslinking reaction, thereby shortening the ultraviolet treatment time. The ultraviolet crosslinking process can also be performed at room temperature, but it is time-consuming. If the irradiation time is insufficient, the crosslinking reaction does not proceed sufficiently; if the irradiation time is too long or the concentration of the crosslinking solvent is too high, the mechanical properties of the polyester monofilament will decrease and the anti-fibrillation ability will decrease. The actual working conditions and economic costs can be comprehensively balanced.

[0023] Preferably, the conventional preparation process of the polyester monofilament includes the steps of drying the polyester chips, melt extrusion, cooling, oiling, drawing and winding,

[0024] Specifically:

[0025] Raw material preparation: Select appropriate polyester chips as raw materials to ensure that their quality meets the requirements.

[0026] Dry and dehumidify: Dry and dehumidify the polyester chips to remove moisture and ensure the stability of subsequent processing.

[0027] Melt extrusion: Add the dried polyester chips into the extruder and melt them by heating.

[0028] Cooling: Cool the sprayed stream by air cooling or water cooling to solidify it into a filament.

[0029] Oiling: Apply a layer of oil on the surface of the filament to increase its softness and smoothness, and reduce friction.

[0030] Stretching: Stretch the cooled filament to improve its strength and toughness. Stretching can be done in multiple stages, usually including hot water stretching, hot air stretching, heat setting, etc.

[0031] Winding: Wind the stretched filament into a roll for subsequent processing and use.

[0032] More preferably, the main process parameters are as follows:

[0033] The drying temperature is 150-170℃;

[0034] The extrusion temperature is 280-300℃;

[0035] The cooling water temperature is 70-80℃;

[0036] The oiling agent concentration is 5-15%;

[0037] The stretching process:

[0038] First roller: speed 20-25m / min;

[0039] Second roller: speed 75-85m / min;

[0040] Third roller: speed 120-130m / min;

[0041] Fourth roller: speed 90-100m / min;

[0042] The heat setting temperature is 240-245℃;

[0043] The winding speed is 30-80m / min.

[0044] The polyester monofilament is prepared by the related limiting parameters of the above conventional preparation process, and can obtain a structure with high crystallinity and high orientation after heat stretching and heat setting, so that the polyester monofilament has excellent mechanical properties, such as high strength (≥500 MPa) and high modulus (≥5 GPa). However, due to the influence of temperature difference in the spinning process, a skin-core structure is formed, which is characterized by low crystallinity and orientation of the inner core layer, and too high crystallinity and orientation of the skin layer. Due to the high orientation of the molecular chains in the skin layer along the fiber axis and the low transverse binding force between the molecular chains, the fibril molecular chains in the skin layer are prone to brittle fracture and splitting in the radial direction under the action of mechanical friction external force, which will macroscopically show floating debris, affecting the fabric precision in the subsequent webbing process. Therefore, on the basis of the conventional preparation process, the skin layer of the polyester monofilament is modified by cross-linking after the ultraviolet cross-linking post-treatment of the application, which can effectively improve the anti-fibrillation effect of the polyester monofilament and obtain a stable anti-fibrillation polyester monofilament, while still retaining its excellent mechanical properties. The application is also applicable to conventional processes with ordinary mechanical properties. It should be noted that the ultraviolet cross-linking treatment of the application can also be applied to other parameters of conventional processes and can improve the anti-fibrillation effect of the polyester monofilament. The application only optimizes the conventional process parameters with excellent mechanical properties, but does not represent a limitation on the technical solutions of the application.

[0045] Preferably, the preparation method of the anti-fibrillation polyester monofilament comprises the following steps: drying, melting extrusion, water cooling, oiling, hot water stretching, hot air stretching, heat setting, ultraviolet cross-linking post-treatment and winding of the polyester chips to obtain the anti-fibrillation polyester monofilament. The main spinning process parameters are as follows:

[0046] The drying temperature is 150-170℃;

[0047] The extrusion temperature is 280-300℃;

[0048] The cooling water temperature is 70-90℃;

[0049] The oiling agent concentration is 5-15%;

[0050] The drawing process is as follows:

[0051] The first roller has a speed of 20-25 m / min;

[0052] The second roller has a speed of 75-85 m / min;

[0053] The third roller has a speed of 120-130 m / min;

[0054] The fourth roller has a speed of 90-100 m / min;

[0055] The heat setting temperature is 235-250℃;

[0056] The winding speed is 30-80 m / min.

[0057] The ultraviolet crosslinking post-treatment process comprises: dipping the prepared polyester monofilament in a mixed solution containing a crosslinking agent for 20-30 s, and then performing heat treatment and ultraviolet crosslinking treatment.

[0058] The second object of the present application is to provide an antigen fibrillation polyester monofilament prepared by any one of the above preparation methods. The antigen fibrillation polyester monofilament is prepared by chemical bonding of a crosslinking agent and a polyester fiber, effectively improving the antigen fibrillation capacity and not affecting the mechanical properties, thereby obtaining a stable and durable antigen fibrillation polyester monofilament with excellent mechanical properties.

[0059] Preferably, the prepared polyester monofilament has an antigen fibrillation improvement degree ≥500% and a mechanical property retention rate ≥90%.

[0060] Preferably, the prepared polyester monofilament has a diameter of 0.2-0.6 mm, a breaking strength ≥500 MPa, and an elongation at break of 10-35%.

[0061] The preparation method of the antigen fibrillation polyester monofilament as described above, the photo-crosslinking agent and the photo-initiator attached to the polyester monofilament rapidly act in the amorphous region of the fiber skin layer under ultraviolet light irradiation, the crosslinking bond enhances the interaction force between the molecular chains, the space network structure formed by crosslinking limits the movement ability of the molecular chains, making it difficult to slip. The increase of crosslinking sites gradually limits the ordered arrangement of the extended molecular chains in the crystal region, which can reduce the crystallinity of the skin layer of the polyester monofilament. The brittleness of the fiber skin layer is reduced, and the interaction force between the fibrils is enhanced, which improves the ability to disperse external stress, thereby achieving the effect of resisting antigen fibrillation.

[0062] The crosslinking reaction process is that the photo-initiator simultaneously abstracts hydrogen on the photo-crosslinking agent and the polyethylene terephthalate to generate free radicals, and the crosslinking reaction occurs between the free radicals to form crosslinking bonds. Taking isocyanuric acid triallyl ester (TAIC) photo-crosslinking agent and benzophenone (BP) photo-initiator as an example, the photo-crosslinking mechanism is as shown in Figure 1 .

[0063] Compared with the prior art, the present application has the following beneficial effects:

[0064] (1) The prepared antigen fibrillation polyester monofilament has a monofilament diameter of 0.2-0.6 mm, a breaking strength ≥500 MPa, and an elongation at break of 10-35%. It can be applied to high-end precision printing industry.

[0065] (2) The application discloses a preparation method of the anti-fibrillation polyester monofilament, which adopts the ultraviolet crosslinking post-processing method, has less capital investment, is safe, simple and convenient to operate, is fast, almost does not pollute the environment, has a small degree of mechanical property damage to the polyester monofilament, and is suitable for industrialized mass production.

[0066] (3) The application discloses a preparation method of the anti-fibrillation polyester monofilament, which improves the crystallinity of the fiber skin layer and enhances the interaction force between the original fiber molecular chains by increasing the crosslinking sites, so that the polyester monofilament has excellent anti-fibrillation capacity, the anti-fibrillation capacity is increased by more than 500% compared with the unmodified polyester monofilament, and the mechanical property is maintained by more than 90% of the original. The application has a wide market application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 It is a schematic diagram of the photo-crosslinking mechanism of the crosslinking reaction. DETAILED DESCRIPTION

[0068] In order to better clarify and understand the purpose, process scheme and advantages of the application, the technical scheme and implementation manner of the application are further clearly, completely and specifically described below by means of specific embodiments and in combination with the drawings. It should be known that the described embodiments of the application are implemented on the premise of the technical scheme of the application, and give a detailed implementation manner and specific operation process, but only a part of the embodiments of the application, not all the embodiments. The specific implementation manner described is limited to the description and explanation of the application, and does not limit the application. Based on the embodiments in the application, all other implementation manners obtained by those skilled in the art without creative labor belong to the protection scope of the application.

[0069] Unless otherwise specified, the experimental methods and conditions used in the following embodiments are conventional methods and conventional conditions. The materials, reagents or instruments used in the embodiments can be obtained from commercial channels unless otherwise specified. The reaction conditions embodied in the inventive content of the application can realize the described reaction and obtain the expected effect product. Due to the limitation of the length, only some embodiments are listed below to further illustrate the advantages of the technical scheme of the application.

[0070] In the embodiments of the application, the anti-fibrillation capacity is represented by the wet rubbing time, and the improvement degree of the anti-fibrillation capacity is represented by (D), and the calculation formula is as follows:

[0071]

[0072] In the formula, t0 is the wet rubbing time of the monofilament without crosslinking treatment; t c is the wet rubbing time of the monofilament after crosslinking treatment.

[0073] The way of evaluating the fibrillation of polyester monofilament in the present application adopts a wet rubbing method, which is based on the characteristics that fibers are easy to be damaged and broken after fibrillation, simulates the environment in which monofilament is easy to fibrillate, and quantifies the anti-fibrillation ability of polyester monofilament by calculating the time for monofilament to be fully fibrillated to break under mechanical rubbing in a wet state. The method refers to the method disclosed in the invention patent with the patent publication number CN102680389A, the patent application number CN201110058072.8, and the patent name of a method for evaluating the fibrillation performance of fibers.

[0074] The mechanical properties of polyester monofilament are evaluated by using a YG026Q fabric strength machine in the present application. The specific test method is as follows: the sample clamping distance is 100 mm, the tensile speed is 250 mm / min, each group of samples is repeatedly tested five times at room temperature, and the average value is taken. The breaking strength (σ), breaking elongation (ε), breaking strength retention rate (R σ ), and breaking elongation retention rate (R ε ) of polyester monofilament are obtained.

[0075] The calculation formula of the breaking strength retention rate (R σ ) is as follows:

[0076]

[0077] In the formula, σ0 is the breaking strength of monofilament without cross-linking treatment; σ c is the breaking strength of monofilament after cross-linking treatment.

[0078] The calculation formula of the breaking elongation retention rate (R ε ) is as follows:

[0079]

[0080] In the formula, ε0 is the breaking elongation of monofilament without cross-linking treatment; ε c is the breaking elongation of monofilament after cross-linking treatment.

[0081] Comparative Example

[0082] A method for preparing polyester monofilament, the steps of which include the steps of drying, melt extrusion, water bath cooling, oiling, hot water stretching, hot air stretching, heat setting, and winding. The spinning process is shown in Table 1.

[0083] Table 1 Spinning process parameters of polyester monofilament with different diameters

[0084]

[0085]

[0086] Example 1

[0087] The polyester monofilament prepared by the method of the comparative example was immersed in a mixed solution containing a photocrosslinking agent and a photoinitiator for 20 s after heat setting, and the types of the photocrosslinking agent and the photoinitiator were as shown in Table 2. The concentration of the photocrosslinking agent in the mixed solution was 0.5 wt%, the concentration of the photoinitiator was 0.5 wt%, the solvent of the mixed solution was ethyl acetate, the heat treatment was performed at 70°C for 5 min, and the ultraviolet crosslinking treatment was performed at 65°C for 120 s, thereby preparing the polyester monofilament having the anti-fibrillation ability. The blank sample was the polyester monofilament without the crosslinking treatment, and was used as a comparative example to detect the influence of the types of the photocrosslinking agent and the photoinitiator on the wet rubbing time, the improvement degree of the anti-fibrillation ability, the breaking strength, the breaking elongation, and the retention rate thereof of the polyester monofilament, and the results were as shown in Table 2.

[0088] Table 2: Summary of results of different types of photocrosslinking agents and photoinitiators

[0089]

[0090]

[0091] The results showed that the polyester monofilaments treated by the same steps had different anti-fibrillation abilities, and compared with the polyester monofilament without the crosslinking treatment (i.e. the blank sample), the anti-fibrillation ability of the monofilament was improved. Among them, benzpinacol and chloranil belong to cleavage-type photoinitiators, and the other several photoinitiators belong to hydrogen abstraction type. It can be seen that the breaking strength and the breaking elongation of the polyester monofilament can be maintained at more than 80% of the blank sample after using two types of photoinitiators. However, the anti-fibrillation effect obtained by the hydrogen abstraction type photoinitiator under the same conditions is obviously better than that of the cleavage-type photoinitiator, and the mechanical property retention rate is stable and maintained at more than 90%.

[0092] Example 2

[0093] The polyester monofilament prepared by the method of the comparative example was immersed in a mixed solution containing a photoinitiator and a photoinitiator for 20 s, and the types of the photocrosslinking agent and the photoinitiator were as shown in Table 2. The concentration of the photocrosslinking agent in the mixed solution was 0.5 wt%, the concentration of the photoinitiator was 0.5 wt%, the solvent of the mixed solution was ethyl acetate, the heat treatment was performed at 70°C for 5 min, and the ultraviolet crosslinking treatment was performed at 65°C for 120 s, thereby preparing the polyester monofilament having the anti-fibrillation ability. The blank sample was the polyester monofilament without the crosslinking treatment, and was used as a comparative example to detect the influence of the types of the photocrosslinking agent and the photoinitiator on the wet rubbing time, the improvement degree of the anti-fibrillation ability, the breaking strength, the breaking elongation, and the retention rate thereof of the polyester monofilament, and the results were as shown in Table 2.

[0094] Table 3 Concentration variation of benzophenone (BP) photoinitiator and result summary table

[0095]

[0096] The results show that when the content of benzophenone photoinitiator is less than 0.25wt%, the mechanical properties are almost not damaged, but the anti-fibrillation ability is poor. Although the anti-fibrillation ability is improved, if the polyester monofilament is applied to high-precision printing screen, this index is still difficult to meet the application requirements. With the increase of the concentration of benzophenone photoinitiator, the anti-fibrillation ability is significantly improved, especially between 0.25wt% and 1.0wt%, the anti-fibrillation ability can be improved by more than 500%, and the mechanical properties are also good, all of which are more than 90% of the blank sample. When the concentration of benzophenone photoinitiator is higher than 1.0wt%, the anti-fibrillation ability and mechanical properties of the polyester monofilament begin to decrease significantly. In summary, the concentration of benzophenone photoinitiator is 0.25wt% to 1.0wt%, the anti-fibrillation effect is good, and the mechanical properties are also good, and 0.5wt% is the best.

[0097] Example 3

[0098] The preparation method of 0.6mm polyester monofilament in the comparative example is used, the prepared polyester monofilament is immersed in a mixed solution containing a photocrosslinking agent and a photoinitiator for 20s, wherein the photocrosslinking agent is triallyl isocyanurate with a certain concentration, and the specific concentration is shown in Table 4, and the photoinitiator is 0.5wt% of benzophenone. The polyester monofilament with anti-fibrillation ability is prepared by heat treatment at 70°C for 5min and ultraviolet crosslinking treatment at 65°C for 120s. The blank sample is a polyester monofilament without crosslinking treatment, which is used as a comparative example to detect the influence of the concentration of the photocrosslinking agent on the wet rubbing time, the improvement degree of the anti-fibrillation ability, the breaking strength, the elongation at break and the retention rate of the polyester monofilament. The results are shown in Table 4:

[0099] Table 4 Concentration variation of triallyl isocyanurate photocrosslinking agent and result summary table

[0100]

[0101]

[0102] The results show that the use of triallyl isocyanurate photo-crosslinking agent can significantly improve the anti-fibrillation ability of polyester monofilament. When the concentration of triallyl isocyanurate photo-crosslinking agent is less than 0.5wt%, the anti-fibrillation ability can be improved by 452.5% based on the blank sample with the increase of the concentration of the crosslinking agent, and the mechanical properties are almost not affected negatively. However, if the polyester monofilament is applied to high-precision printing screen, this index is still difficult to meet the application requirements. With the continuous increase of triallyl isocyanurate photo-crosslinking agent, the anti-fibrillation ability of polyester monofilament is significantly improved, especially between 0.5wt% and 5.0wt%, the anti-fibrillation ability can be stably improved by more than 500%. However, when the concentration of the crosslinking agent is more than 2.0wt%, the breaking strength and elongation at break of the polyester monofilament are significantly reduced, and the retention rate is less than 90%, which is difficult to meet the application requirements. In summary, the anti-fibrillation ability is better when the concentration of triallyl isocyanurate photo-crosslinking agent is between 0.5wt% and 2.0wt%, and the mechanical properties are also maintained at more than 90%, among which 0.5wt% is the best.

[0103] Example 4

[0104] The preparation method of 0.2mm polyester monofilament in Example 1 was used, and the heat treatment conditions were changed. The prepared polyester monofilament was immersed in a mixed solution containing photo-crosslinking agent and photo-initiator for 20s, wherein the photo-crosslinking agent was 0.5wt% triallyl isocyanurate, and the photo-initiator was 0.5wt% benzophenone, and heat treatment was carried out under different conditions. The specific conditions are shown in Table 5. The polyester monofilament with anti-fibrillation ability was prepared by ultraviolet crosslinking treatment at a temperature of 65℃ for 120s. The blank sample was the polyester monofilament without crosslinking treatment, which was used as a comparative example to detect the influence of heat treatment temperature and time on the wet rubbing time, anti-fibrillation ability improvement degree, breaking strength, elongation at break and its retention rate of the polyester monofilament. The results are shown in Table 5:

[0105] Table 5 Heat treatment condition change and result summary table

[0106]

[0107]

[0108] The results show that when the heat treatment temperature is lower than 70°C, the antigen fibrillation ability of the polyester monofilament is not significantly improved based on the antigen fibrillation ability of the blank sample, and the mechanical properties are significantly affected due to uneven crosslinking. As the heat treatment temperature increases, the antigen fibrillation ability increases, but when the temperature exceeds 90°C, the antigen fibrillation ability and mechanical properties may significantly decrease. In addition, under the same heat treatment temperature conditions, the antigen fibrillation ability of the polyester monofilament increases with the increase of heat treatment time, and it is difficult to ensure that the antigen fibrillation ability reaches the expected effect before 5 min of heat treatment, and the antigen fibrillation of the sample is basically stable after 10 min of heat treatment. Considering that increasing the heat treatment time will not only increase the cost, but also affect the mechanical properties of the fiber. Therefore, combined with the above experimental data, considering the cost and other factors, the heat treatment temperature is controlled between 70-90°C to ensure good antigen fibrillation ability, and the heat treatment time is controlled between 5-10 min, and the comprehensive performance of the fiber is best.

[0109] Example 5

[0110] The preparation method of the 0.2 mm polyester monofilament in Example 1 was used, and the ultraviolet crosslinking time was changed. The prepared polyester monofilament was immersed in a mixed solution containing a photo-crosslinking agent and a photo-initiator for 20 s, wherein the photo-crosslinking agent was 0.5 wt% triallyl isocyanurate, and the photo-initiator was 0.5 wt% benzophenone. The polyester monofilament was heat treated at 70°C for 5 min, and then ultraviolet crosslinked at a temperature of 65°C for a certain time, as shown in Table 6. The polyester monofilament with antigen fibrillation ability was prepared. The blank sample was a polyester monofilament without crosslinking treatment, which was used as a comparative example to detect the effects of heat treatment temperature and time on the wet rubbing time, antigen fibrillation ability, breaking strength and elongation at break of the polyester monofilament. The results are shown in Table 6:

[0111] Table 6: Ultraviolet crosslinking condition changes and result summary table

[0112]

[0113]

[0114] The results show that under certain conditions, the longer the UV crosslinking time, the stronger the anti-fibrillation ability of the polyester monofilament. When the UV crosslinking time is 150 s, the anti-fibrillation ability of the fiber is improved by 918.9% compared with the blank sample, and the mechanical properties can be maintained at more than 90%. Then, increasing the UV crosslinking time, the anti-fibrillation ability of the fiber changes unobviously, and the breaking strength and elongation at break decrease significantly. In addition, the above data show that under the condition of UV crosslinking time of 150 s, with the increase of UV crosslinking temperature, the anti-fibrillation ability of the fiber is enhanced, while the mechanical properties show a downward trend. When the UV crosslinking temperature is 65℃, the anti-fibrillation ability is improved by 918.9% compared with the blank sample, and then the anti-fibrillation ability and the mechanical properties decrease significantly with the increase of temperature. In summary, considering the above data, the UV crosslinking time is 120-150 s, and the UV crosslinking temperature is 55-65℃, which has a good anti-fibrillation effect and can also have excellent mechanical properties.

[0115] The above-described embodiments are only the preferred schemes of the present application, and do not limit the present application in any form. There are other variants and modifications without exceeding the technical solutions recited in the claims.

Claims

1. A process for the preparation of an anti-fibrillogenic polyester monofilament, characterized in that: The preparation method comprises: preparing polyester monofilament; and UV crosslinking post-treatment, which comprises the following steps: (1) immersing the prepared polyester monofilament in a solution containing a crosslinking agent; (2) heat treating the immersed polyester monofilament; (3) performing a UV crosslinking step on the heat treated polyester monofilament to complete the UV crosslinking post-treatment; In the step (1), the concentration of the crosslinking agent in the solution containing the crosslinking agent is 0.5-2 wt%, and the crosslinking agent is at least one selected from triallyl isocyanurate, triallyl cyanurate, pentaerythritol triallyl, and glycidyl methacrylate; The solution containing the crosslinking agent in the step (1) also contains a photoinitiator, and the concentration of the photoinitiator in the solution is 0.25-1 wt%. The photoinitiator is a hydrogen abstraction type initiator.

2. The method for preparing an antigen-fiberized polyester monofilament according to claim 1, characterized in that: The immersion in the step (1) is performed for 20-30 s.

3. The method for preparing antigen-fiberized polyester monofilament according to claim 1, characterized in that: The heat treatment in the step (2) is performed at a temperature of 70-90 ℃ for not less than 5 min.

4. The method for preparing an antigen-fiberized polyester monofilament according to claim 1, characterized in that: The UV crosslinking step in the step (3) is performed at a UV light peak value of 280-400 nm, a UV crosslinking temperature of 55-65 ℃, and a UV crosslinking time of 120-150 s.

5. The method for preparing an antigen-fiberized polyester monofilament according to claim 1, characterized in that: The preparation process of the polyester monofilament without UV crosslinking treatment comprises the following steps: drying of polyester chips, melt extrusion, water cooling, oiling, drawing, and heat setting, and the main process parameters are as follows: the drying temperature is 150-170 ℃; The extrusion temperature is 280-300 ℃; The water temperature for cooling is 70-80 ℃; The concentration of the oiling agent is 5-15%; The drawing process is as follows: First roller: speed of 20-25 m / min; Second roller: speed of 75-85 m / min; Third roller: speed of 120-130 m / min; Fourth roller: speed of 90-100 m / min; The heat setting temperature is 240-245 ℃.

6. An antigen fibrillation polyester monofilament prepared by the preparation method according to any one of claims 1-5.

7. An anti-fibrillogenic polyester monofilament according to claim 6, characterized in that: The prepared polyester monofilament has an antigen fibrillation capacity improvement degree of ≥500%, a mechanical property retention rate of ≥90%, a diameter of 0.2-0.6 mm, a breaking strength of ≥500 MPa, and an elongation at break of 10-35%.

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