A white polyethylene fiber membrane and its preparation method

Abstract

This application discloses a white polyethylene fiber membrane and its preparation method, belonging to the field of polymer materials technology. The product described in this application introduces a specific resin system together with modified titanium dioxide as the basic component, and at the same time limits the ratio of fineness to specific surface area of ​​the flash-spun fiber after preparation, so that the product will not show obvious "powdering" phenomenon after friction while ensuring sufficient wear resistance. At the same time, the product has excellent air permeability and water permeability.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, specifically to a white polyethylene fiber membrane and its preparation method. Background Technology

[0002] Flash-spun fiber membranes are a novel material with excellent comprehensive properties. They are prepared by instantaneously releasing polymer raw materials from a high-temperature, high-pressure environment to room temperature and pressure, thereby forming a spun fiber membrane. Compared with similar polymer products prepared by traditional processes, flash-spun fiber membranes have higher mechanical strength, lower basis weight, more uniform fiber distribution, and better air permeability, making them ideal for the preparation of products such as medical and industrial protective clothing.

[0003] However, when flash-spun fibers are used in industrial protective clothing, a high-density fiber layer is constructed during the flash-spun fiber membrane preparation process to effectively isolate harmful substances such as dust and ensure sufficient abrasion resistance. This reduces the interlayer / fiber gaps, decreasing overall air permeability and moisture permeability. In hot or stuffy environments, the heat vapor generated after wearing the clothing cannot escape quickly, leading to excessive sweating. Furthermore, since most industrial protective clothing is predominantly white, the pigments used are often inorganic pigments such as titanium dioxide. These inorganic pigments are prone to shedding powder after repeated friction, and the hydroxyl groups on these inorganic powders at the microscopic level more easily trap water molecules, preventing the effective release of moisture-containing air and further reducing the product's air and water permeability. Summary of the Invention

[0004] Based on the deficiencies of the existing technology, the purpose of this application is to provide a white polyethylene fiber membrane. By introducing a specific resin system together with modified titanium dioxide as the basic component, and at the same time limiting the ratio of fiber strength to specific surface area of ​​the flash-spun fibers after preparation, the product can ensure sufficient wear resistance without obvious "powdering" after friction, while the product has excellent air and water permeability.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] A white polyethylene fiber membrane includes flash-evaporated fibers, the flash-evaporated fibers comprising the following components in parts by weight: 80-85 parts HDPE, 1-3 parts LLDPE, 7-9 parts modified titanium dioxide, 1-3 parts lubricant, and 1-3 parts compatibilizer.

[0007] Modified titanium dioxide includes hyperbranched polyester-grafted modified titanium dioxide.

[0008] Compatibilizers include tetrabutyl titanate and EVA resin.

[0009] White polyethylene fiber membrane meets the following requirements: 9.5 ≤ D / B ≤ 20.

[0010] Where DCN / dtex is the single-bundle fiber strength of the flash fiber, and Bm 2 / g represents the specific surface area of ​​the white polyethylene fiber membrane.

[0011] Flash spinning is a technique that uses polymers as raw materials, disperses them in a low-boiling-point solvent, and forms a sub-equilibrium spinning solution under high temperature and high pressure. The solution is then transferred to a spinning device and instantly released to a normal temperature and pressure environment. At this point, the material in the solution is transformed into filaments and uniformly dispersed and stacked into a web through air or electrostatic guidance. Currently, it is mainly used for flash spinning of polyethylene systems. The films prepared by this material (which are actually similar to non-woven fabrics) have higher mechanical strength, better uniformity, and smaller weight compared to similar products formed by traditional spinning technology or by directly rolling and blowing polyethylene materials. However, existing polyethylene flash-spun membrane materials use high-density polyethylene as raw material and prepare high-density finished products to ensure sufficient abrasion resistance. Although this approach results in high abrasion resistance, the water and air permeability is extremely poor, leading to low comfort when used in industrial protective clothing. Furthermore, because these products require the introduction of white inorganic pigments as dyes, these pigments are not highly compatible with organic resins and tend to accumulate on the material surface after spinning, gradually falling off after friction. At the same time, these pigments have a certain degree of water absorption, making it even more difficult to achieve good drainage and air ventilation effects.

[0012] Therefore, in this application, the inventors, based on the existing polyethylene system flash-spun fiber membrane formulation, modified the inorganic pigment titanium dioxide with hyperbranched polyester grafting. Simultaneously, they selected specific tetrabutyl titanate and EVA resin as compatibilizers for compounding. Since titanium dioxide, besides serving as a pigment in the product, also contains a porous structure that adsorbs liquid or gas phases (such as air) during product preparation, during flash spinning, the liquid phase (vaporized into gas) or gas phase is rapidly discharged and forms pathways within the product. Therefore, this portion of titanium dioxide actually also has a "pore-forming" effect. To improve the product's air and water permeability, hyperbranched polyester grafted with titanium dioxide not only significantly improves its compatibility with polyethylene resin, but also effectively reduces the water absorption effect caused by the hydroxyl groups on its surface. On the other hand, in order to improve the bonding strength of titanium dioxide and the wear resistance of the product itself in HDPE and LLDPE matrix resins, the inventors discovered through experiments that using tetrabutyl titanate and EVA resin as a compatibilizer can not only fully disperse and bind the modified titanium dioxide in the resin system, but also improve the product's impact resistance and friction resistance, resulting in high wear resistance of the product itself.

[0013] On the other hand, simply designing the product's composition is not enough to solve the problems of insufficient moisture permeability and frictional "powder shedding". Therefore, the inventors further controlled the strength and density of the flash spinning in the product and found that as long as the ratio of the product's specific surface area to the strength of a single bundle of spun fibers is further limited under the condition of appropriate composition, the problem of water droplets condensing between fibers during the moisture permeation process and being unable to pass through due to surface tension, as well as the problem of local "powder shedding" caused by the large force on a single point of the material during the friction process, can be suppressed.

[0014] Preferably, the HDPE has a melt index of greater than or equal to 5 g / 10 min and less than or equal to 10 g / 10 min at 190 °C and 2.16 kg load, according to ASTM D1238.

[0015] More preferably, the HDPE has a melt index of 5 g / 10 min, 5.5 g / 10 min, 6 g / 10 min, 6.5 g / 10 min, 7 g / 10 min, 7.5 g / 10 min, 8 g / 10 min, 8.5 g / 10 min, 9 g / 10 min, 9.5 g / 10 min, or 10 g / 10 min, according to ASTM D1238 at 190°C and 2.16 kg load, or any two of these values.

[0016] Preferably, the LLDPE has a melt index of greater than or equal to 10 g / 10 min and less than or equal to 50 g / 10 min at 190 °C and 2.16 kg load, according to ASTM D1238.

[0017] More preferably, the LLDPE has a melt index of 10 g / 10 min, 12 g / 10 min, 15 g / 10 min, 18 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min, 45 g / 10 min, or 50 g / 10 min, according to ASTM D1238 at 190 °C and 2.16 kg load, or any two of these values.

[0018] Preferably, the hyperbranched polyester grafted titanium dioxide is a hyperbranched polyester melt-grafted titanium dioxide.

[0019] More preferably, the hyperbranched polyester is an amide-based dendritic hyperbranched polyolefin.

[0020] Preferably, the mass ratio of titanium dioxide to hyperbranched polyester in hyperbranched polyester grafted titanium dioxide is 1:(0.05-0.25).

[0021] More preferably, the mass ratio of titanium dioxide to hyperbranched polyester in hyperbranched polyester-modified titanium dioxide is 1:(0.1 to 0.2).

[0022] In traditional white fiber membrane products, titanium dioxide easily absorbs and stores water due to the effect of its surface hydroxyl groups. However, when amide-based dendritic hyperbranched polyolefins are grafted onto it, not only can the surface hydroxyl groups be fully consumed, but the bonding strength of the grafted material on the titanium dioxide surface can also be further improved. At the same time, under a specific grafting ratio, the hyperbranched polyester will not block the pore structure of the titanium dioxide surface. However, if a large amount is introduced, it may lead to surface pore blockage, weaken the pore-forming effect of titanium dioxide, and affect the air permeability and moisture permeability of the product.

[0023] More preferably, the preparation method of hyperbranched polyester grafted modified titanium dioxide includes the following steps: titanium dioxide is soaked on the surface of a silane coupling agent, mixed with hyperbranched polyester and placed in a screw extruder, then an initiator is added and melt extruded at 160-210°C to obtain hyperbranched polyester grafted modified titanium dioxide.

[0024] It should be noted that the hyperbranched polyester grafted modified titanium dioxide of this application is not limited to the melt grafting described above. Based on common knowledge, those skilled in the art can also use other grafting methods such as solvent phase grafting to prepare hyperbranched polyester grafted modified titanium dioxide, or even directly purchase existing products based on actual conditions, as long as their performance can meet the expectations of the product of this application.

[0025] Preferably, the lubricant includes at least one of silicone lubricants, amide lubricants, and stearic acid lubricants.

[0026] Preferably, the compatibilizer is a mixture of tetrabutyl titanate and EVA resin.

[0027] Preferably, the mass ratio of tetrabutyl titanate to EVA resin is (1:9) to (4:6).

[0028] More preferably, the mass ratio of tetrabutyl titanate to EVA resin is (2:8) to (3:7).

[0029] Tetrabutyl titanate (TBT) in polyethylene plastic systems can enhance the crosslinking and adhesion between inorganic fillers and the matrix resin. EVA resin, due to the presence of vinyl acetate in its molecular weight, can reduce its crystallinity and improve its toughness and abrasion resistance when compounded with polyethylene resin. It can also synergistically enhance the compatibility of titanium dioxide in polyethylene resin with TTB. However, TTB has some water absorption; therefore, when compounded with compatibilizers within the aforementioned preferred range, the product can achieve optimal abrasion resistance and breathability / moisture permeability.

[0030] More preferably, the EVA resin, according to GB / T 3682.1, has a melt flow rate of greater than or equal to 2 g / 10 min and less than or equal to 10 g / 10 min at 190 °C and 2.16 kg load.

[0031] Preferably, the ratio D / B of the single bundle fiber strength of the flash fiber to the specific surface area of ​​the white polyethylene fiber membrane is a value within the range of one or both of the following: 9, 9.5, 10, 12, 15, 15.5, 18, 19.5, and 20.

[0032] More preferably, the ratio of the single bundle fiber strength of the flash fiber to the specific surface area of ​​the white polyethylene fiber membrane, D / B, is 9.86 to 17.6.

[0033] Preferably, the specific surface area B of the white polyethylene fiber membrane is greater than or equal to 8 m². 2 / g and less than or equal to 15m 2 / g.

[0034] More preferably, the specific surface area B of the white polyethylene fiber film is 8m². 2 / g、9m 2 / g, 10m 2 / g、11m 2 / g、12m 2 / g、13m 2 / g、14m 2 / g, 15m 2 The range of one or both of the values ​​in / g.

[0035] More preferably, the specific surface area B of the white polyethylene fiber membrane is greater than or equal to 10.2 m². 2 / g and less than or equal to 14.5m 2 / g.

[0036] More preferably, the specific surface area of ​​the white polyethylene fiber membrane can be confirmed by nitrogen adsorption-desorption method, and the desorption branch curve value is used for confirmation.

[0037] Preferably, the single-bundle fiber strength of the flash fiber is greater than or equal to 130 CN / dtex and less than or equal to 200 CN / dtex.

[0038] More preferably, the single-bundle fiber strength of the flash fiber is a value within the range of one or any two of the following: 130 CN / dtex, 135 CN / dtex, 140 CN / dtex, 145 CN / dtex, 150 CN / dtex, 155 CN / dtex, 160 CN / dtex, 165 CN / dtex, 170 CN / dtex, 175 CN / dtex, 180 CN / dtex, 185 CN / dtex, 190 CN / dtex, 195 CN / dtex, and 200 CN / dtex.

[0039] More preferably, the single-bundle fiber strength of the flash fiber is greater than or equal to 143 CN / dtex and less than or equal to 180 CN / dtex.

[0040] More preferably, the single-bundle fiber strength of the flash fiber is confirmed using the standard test method FZ / T 50046-2019.

[0041] As the strength of a single bundle of flash-spun fibers increases, their abrasion resistance increases during external friction. However, the shrinkage between fibers decreases. Furthermore, the maximum contact area and surface tension generated when water-containing gases or water vapor come into contact with the fibers and their gaps will also differ. Therefore, only by fully controlling the microstructure of the flash-spun fibers and further regulating their fiber strength and weaving tightness can we ensure that the product truly balances strength, color intensity, and breathability and moisture permeability.

[0042] Preferably, in the white polyethylene fiber membrane, LLDPE, modified titanium dioxide, lubricant, and compatibilizer are introduced in the form of masterbatch.

[0043] More preferably, the method for preparing the masterbatch includes the following steps:

[0044] LLDPE, modified titanium dioxide, lubricant, and compatibilizer are mixed and then melt-extruded into granules at 90–180°C in a twin-screw extruder to obtain masterbatch.

[0045] Another object of this application is to provide a method for preparing a white polyethylene fiber film, comprising the following steps:

[0046] Each component is added to a reaction vessel containing a solvent, and then heated and nitrogen gas is introduced to make the temperature inside the reaction vessel greater than or equal to 200°C and less than or equal to 230°C, and the pressure greater than or equal to 10MPa and less than or equal to 12MPa, to obtain a spinning solution.

[0047] The spinning solution is placed in a flash spinning device for spinning and the film is formed by receiving the fiber film through a receiving device. The resulting fiber film is then cold-pressed and hot-rolled to obtain a white polyethylene film.

[0048] Preferably, the solvent has a boiling point ≤100℃.

[0049] More preferably, the solvent includes at least one of benzene, toluene, butane, pentene, n-hexane, heptane, octane, cyclohexane, dichloromethane, carbon tetrachloride, chloroform, chloromethane, chlorofluoromethane, and chloroethane.

[0050] More preferably, the mass ratio of the solid phase to the liquid phase in the spinning solution is (10:90) to (30:70).

[0051] More preferably, the flash spinning device is prepared using the production equipment 300 used in the inventor's prior research and development technology CN115323628B.

[0052] It should be noted that the products of this application are not limited to the production equipment mentioned above. Those skilled in the art can also use other types of flash evaporation production equipment to produce the products according to actual needs, as long as products with the same technical features and effects can be prepared.

[0053] The beneficial effects of this application are that it provides a white polyethylene fiber membrane, which introduces a specific resin system together with modified titanium dioxide as the basic component, and limits the ratio of fiber strength to specific surface area of ​​the flash-spun fiber after preparation, so that the product will not show obvious "powdering" phenomenon after friction while ensuring sufficient wear resistance, and the product has excellent air permeability and water permeability. Detailed Implementation

[0054] To better illustrate the purpose, technical solution, and advantages of this application, the following description, in conjunction with specific embodiments and comparative examples, aims to provide a detailed understanding of the content of this application, rather than limiting it. All other embodiments obtained by those skilled in the art without inventive effort are within the protection scope of this application. Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this application are all commonly used reagents and instruments.

[0055] Examples 1, 4-13

[0056] This application discloses an embodiment of a white polyethylene fiber membrane and its preparation method. The composition of the white polyethylene fiber membrane is shown in Table 1.

[0057] The method for preparing a white polyethylene fiber film includes the following steps:

[0058] (1) Masterbatch preparation: LLDPE, modified titanium dioxide, lubricant and compatibilizer are mixed and then transferred to a twin-screw extruder for melt extrusion granulation at 90-180℃ to obtain masterbatch; the temperature settings of the twin-screw extruder are: Zone 1 90-110℃, Zone 2 120-130℃, Zone 3 150-160℃, Zone 4 170-180℃, Zone 5 170-185℃, Zone 6 170-185℃, Zone 7 160-165℃, Zone 8 160-165℃, Zone 9 160-165℃, Zone 10 160-165℃; the screw speed of the twin-screw extruder is 180-220 rpm;

[0059] (2) Preparation of spinning solution: HDPE and masterbatch are mixed and then transferred to a reaction vessel containing a mixed solvent (15%:85%) of difluorochloromethane and tetrafluorodichloroethane. The mixture is preheated to 180°C, then nitrogen gas is introduced to pressurize it to 12MPa, and finally the temperature is raised to 225°C and stirred in a closed container for 2 hours. After the temperature stabilizes, the spinning solution is obtained. The mass ratio of solid phase to liquid phase in the spinning solution is 15:85.

[0060] (3) Preparation of white polyethylene fiber film: Referring to CN115323628B, a flash spinning equipment 300 was used to transfer the spinning solution to the nozzle for spinning. The filaments were then refracted and reflected by a rotating splitter to form a mesh and laid on a moving screen. The speed of the ejected airflow was 12000 m / min, the frequency of the rotating splitter was 35 Hz, and the forward speed of the moving screen was 45 m / min. The collected mesh was cold-pressed at 0.5-1 MPa and hot-rolled at 140℃ and 3-3.5 MPa (hot rolling roller speed was 45-50 m / min) to obtain a white polyethylene fiber film with a thickness of about 0.12 mm. The specific surface area and single fiber strength of the product are shown in Table 1.

[0061] Example 2

[0062] An embodiment of a white polyethylene fiber film and its preparation method is disclosed in this application. The difference from Embodiment 1 is only that step (3) in the product preparation method is as follows: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning. The solution is then refracted and reflected by a rotating filament splitter to form a mesh and laid on a moving screen. The speed of the ejected airflow is 12500 m / min, the frequency of the rotating filament splitter is 40 Hz, and the forward speed of the moving screen is 40 m / min. The collected mesh is cold-pressed at 0.5-1 MPa and hot-rolled at 140°C and 3-3.5 MPa (hot rolling roller speed is 45-50 m / min) to obtain a white polyethylene fiber film with a thickness of about 0.1 mm.

[0063] Example 3

[0064] An embodiment of a white polyethylene fiber film and its preparation method is disclosed in this application. The difference from Embodiment 1 is only that step (3) in the product preparation method is as follows: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning. The filaments are then refracted and reflected by a rotating filament splitting plate to form a mesh and are laid on a moving screen. The speed of the ejected airflow is 11500 m / min, the frequency of the rotating filament splitting plate is 30 Hz, and the forward speed of the moving screen is 50 m / min. The collected mesh is cold-pressed at 0.5-1 MPa and hot-rolled at 140°C and 3-3.5 MPa (hot rolling roller speed is 45-50 m / min) to obtain a white polyethylene fiber film with a thickness of about 0.1 mm.

[0065] Comparative Examples 1-8

[0066] The only difference between each comparative example and the embodiment is the type and ratio of components, as shown in Table 2.

[0067] Comparative Example 9

[0068] A white polyethylene fiber membrane and its preparation method differ from Example 1 only in step (3) of the product preparation method: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning, and then the spinning solution is refracted and reflected by the rotating filament splitting plate to form a mesh and laid on the moving screen. The speed of the sprayed airflow is 13000m / min, the frequency of the rotating filament splitting plate is 45Hz, and the forward speed of the moving screen is 35m / min. The collected mesh is cold-pressed at 0.5-1MPa pressure and hot-rolled at 140℃ and 3-3.5MPa pressure (hot rolling roller speed is 45-50m / min) to obtain a white polyethylene fiber membrane with a thickness of about 0.1mm. The specific surface area and single fiber strength of the product are shown in Table 1.

[0069] Comparative Example 10

[0070] A white polyethylene fiber membrane and its preparation method differ from Example 1 only in that step (3) of the product preparation method is as follows: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning. Then, the spinning solution is refracted and reflected by a rotating filament splitter to form a mesh and is laid on a moving screen. The speed of the ejected airflow is 11000 m / min, the frequency of the rotating filament splitter is 25 Hz, and the forward speed of the moving screen is 55 m / min. The collected mesh is cold-pressed at 0.5-1 MPa and hot-rolled at 140°C and 3-3.5 MPa (hot rolling roller speed is 45-50 m / min) to obtain a white polyethylene fiber membrane with a thickness of about 0.1 mm. The specific surface area and single fiber strength of the product are shown in Table 1.

[0071] Comparative Example 11

[0072] A white polyethylene fiber membrane and its preparation method differ from Example 1 only in that step (3) of the product preparation method is as follows: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning. Then, the spinning solution is refracted and reflected by a rotating filament splitter to form a mesh and is laid on a moving screen. The speed of the ejected airflow is 10000 m / min, the frequency of the rotating filament splitter is 35 Hz, and the forward speed of the moving screen is 45 m / min. The collected mesh is cold-pressed at 0.5-1 MPa and hot-rolled at 140°C and 3-3.5 MPa (hot rolling roller speed is 45-50 m / min) to obtain a white polyethylene fiber membrane with a thickness of about 0.1 mm. The specific surface area and single fiber strength of the product are shown in Table 1.

[0073] Comparative Example 12

[0074] A white polyethylene fiber membrane and its preparation method differ from Example 1 only in step (3) of the product preparation method: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning, and then the spinning solution is refracted and reflected by the rotating filament splitting plate to form a mesh and laid on the moving screen; the speed of the sprayed airflow is 14000m / min, the frequency of the rotating filament splitting plate is 35Hz, and the forward speed of the moving screen is 45m / min; the collected mesh is cold-pressed at 0.5-1MPa pressure and hot-rolled at 140℃ and 3-3.5MPa pressure (hot rolling roller speed is 45-50m / min) to obtain a white polyethylene fiber membrane with a thickness of about 0.1mm. The specific surface area and single fiber strength of the product are shown in Table 1.

[0075] Comparative Example 13

[0076] A white polyethylene fiber film and its preparation method differ from Example 1 only in that step (3) of the product preparation method is as follows: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning, and then the spinning solution is refracted and reflected by the rotating filament splitting plate to form a mesh and laid on the moving screen. The speed of the sprayed airflow is 12000m / min, the frequency of the rotating filament splitting plate is 45Hz, and the forward speed of the moving screen is 20m / min. The collected mesh is cold-pressed at 0.5-1MPa pressure and hot-rolled at 140℃ and 3-3.5MPa pressure (hot rolling roller speed is 45-50m / min) to obtain a white polyethylene fiber film with a thickness of about 0.12mm.

[0077] Comparative Example 14

[0078] A white polyethylene fiber film and its preparation method differ from Example 1 only in that step (3) of the product preparation method is as follows: Referring to CN115323628B, a flash spinning equipment 300 is used to transfer the spinning solution to the nozzle for spinning, and then the spinning solution is refracted and reflected by the rotating filament splitting plate to form a mesh and laid on the moving screen. The speed of the sprayed airflow is 12000m / min, the frequency of the rotating filament splitting plate is 45Hz, and the forward speed of the moving screen is 55m / min. The collected mesh is cold-pressed at 0.5-1MPa pressure and hot-rolled at 140℃ and 3-3.5MPa pressure (hot rolling roller speed is 45-50m / min) to obtain a white polyethylene fiber film with a thickness of about 0.12mm.

[0079] In each embodiment and comparative example component,

[0080] HDPE is Braskem's 7260 product, with a melt index of 7 g / 10 min at 190°C and a load of 2.16 kg.

[0081] LLDPE is a 7144 product manufactured by Sinopec, with a melt index of 22g / 10min at 190℃ and 2.16kg load.

[0082] Modified titanium dioxide 1 was prepared in-house. The preparation method was as follows: commercially available rutile titanium dioxide R350 was soaked in silane coupling agent KH550, and then mixed with hyperbranched polyester HBP158 produced by Wuhan Hyperbranched Chemical Co., Ltd. at a mass ratio of 1:0.1 and placed in a twin-screw extruder. Then, an appropriate amount of initiator DCP was added and melt-extruded at an extrusion temperature of 160-210℃ and a screw speed of 300 rpm to obtain hyperbranched polyester grafted modified titanium dioxide.

[0083] Modified titanium dioxide 2 was prepared in-house, and its only difference from modified titanium dioxide 1 was that the mass ratio of titanium dioxide to hyperbranched polyester was 1:0.2.

[0084] Modified titanium dioxide 3 is self-made, and the only difference between it and modified titanium dioxide 1 is that the mass ratio of titanium dioxide to hyperbranched polyester is 1:0.05.

[0085] Modified titanium dioxide 4 was prepared in-house, and its only difference from modified titanium dioxide 1 was that the mass ratio of titanium dioxide to hyperbranched polyester was 1:0.25.

[0086] Modified titanium dioxide 5 is self-made, and the only difference between it and modified titanium dioxide 1 is that the hyperbranched polyester is a non-amide-based dendritic hyperbranched polyester HyPer C100.

[0087] Modified titanium dioxide 6 is self-made, and the only difference between it and modified titanium dioxide 1 is that the hyperbranched polyester is a non-amide-based dendritic hyperbranched polyester HyPer H10.

[0088] Modified titanium dioxide 7 is self-made, and the only difference between it and modified titanium dioxide 1 is that the hyperbranched polyester is a non-amide-based dendritic hyperbranched polyester HyPer H20.

[0089] Modified titanium dioxide 8 is prepared in-house. The preparation method is as follows: commercially available rutile titanium dioxide R350 is soaked in silane coupling agent KH550 and then dried to obtain modified titanium dioxide.

[0090] The titanium dioxide is commercially available rutile titanium dioxide R350.

[0091] The lubricant is commercially available erucamide.

[0092] Compatibilizer 1 is a mixture of tetrabutyl titanate and EVA resin in a mass ratio of 2:8; EVA is V6110MC produced by Yangzi-BASF, with a melt flow rate of 5.2 g / 10 min at 190℃ and 2.16 kg load.

[0093] Compatibilizer 2 is a mixture of tetrabutyl titanate and EVA resin in a mass ratio of 3:7.

[0094] Compatibilizer 3 is a mixture of tetrabutyl titanate and EVA resin in a mass ratio of 1:9.

[0095] Compatibilizer 4 is a mixture of tetrabutyl titanate and EVA in a mass ratio of 4:6.

[0096] Compatibilizer 5 is tetrabutyl titanate.

[0097] Compatibilizer 6 is EVA.

[0098] Compatibilizer 7 was replaced with tetrabutyl titanate and Clariant's PE520 model PE wax.

[0099] Compatibilizer 8 was replaced with Clariant's PE520 model PE wax instead of EVA resin.

[0100] Unless otherwise specified, all components and raw materials used in the embodiments and comparative examples of this application are commercially available, and the same type of components and raw materials are used in each parallel experiment.

[0101] Table 1

[0102]

[0103]

[0104]

[0105] Table 2

[0106]

[0107] To verify the performance of the white polyethylene fiber membrane of this application, the products prepared in each embodiment and comparative example were subjected to the following performance tests, the specific steps of which are as follows:

[0108] (1) Air permeability performance: The products of each embodiment and comparative example were tested according to GB / T 5453-1997 (area 20cm²). 2 (Pressure difference 200Pa);

[0109] (2) Moisture permeability performance: The products of each embodiment and comparative example were tested according to GB / T 12704.1-2009 (condition a);

[0110] (3) Abrasion resistance test: Each example and comparative product was tested according to EN 530 (load 9kg, abrasive is sandpaper).

[0111] (4) Powder shedding test: Two samples of the same area from each embodiment and comparative example were subjected to a load and rubbed against each other 100 times. The rubbing area range was ±20%. Observation was performed to check whether powder fell off after the friction (area 20cm²). 2 (Total load 1kg).

[0112] The test results are shown in Tables 3 and 4.

[0113] Table 3

[0114]

[0115] Table 4

[0116]

[0117] As shown in Tables 3 and 4, the white polyethylene fiber membrane of this application, based on the control and selection of component and morphology parameters, not only achieves good air permeability and moisture permeability (air permeability exceeding 10.5 mm / s and moisture permeability exceeding 4000 g / m / 2*24h), but also achieves over 550 abrasion resistance tests. No powder shedding was observed in the inter-group sample simulated friction experiment, demonstrating excellent abrasion resistance and high colorant bonding strength. In contrast, the products in Comparative Examples 1 and 2, prepared using conventional unmodified titanium dioxide or only silane coupling agent-modified titanium dioxide as colorant, not only have poor air permeability and moisture permeability, but also unsatisfactory abrasion resistance, exhibiting powder shedding after friction. This indicates that the titanium dioxide in these products, without modification by hyperbranched polyester, not only fails to achieve the "pore-forming effect," but also fails to guarantee uniformity and the bonding strength with the matrix resin. On the other hand, without the use of a compatibilizer to compound the modified inorganic pigments, as shown in Comparative Example 4, the product also fails to achieve good overall performance, even performing worse than the product in Comparative Example 2, which uses silane coupling modified titanium dioxide. However, if too much compatibilizer is introduced, as recorded in Comparative Example 3, although the product has excellent air permeability and abrasion resistance, the moisture permeability deteriorates due to the water absorption of tetrabutyl titanate itself. In Comparative Examples 5-8, Comparative Examples 5 and 6 used only tetrabutyl titanate and EVA resin as compatibilizers, respectively, and the air permeability and moisture permeability of the products were not ideal, indicating that only when both are used in combination can the product achieve the expected air permeability and moisture permeability. In Comparative Examples 7 and 8, one of them was replaced with PE wax, a compatibilizer commonly used in polyethylene resin products. Obviously, it cannot be synergistically compounded with the other, and the air permeability and moisture permeability of the products were not significantly improved compared to Comparative Examples 5 and 6. In Comparative Examples 9 to 14, although the component formulations used were exactly the same as those in Example 1, the products still could not achieve the ideal overall performance because the ratio of fiber strength to product specific surface area was not within the range specified in this application.

[0118] As can be seen from Examples 1 and 5-7, the amount of hyperbranched polyester introduced during titanium dioxide modification has a certain impact on the product performance, but more is not necessarily better. When the mass ratio of titanium dioxide to hyperbranched polyester in the hyperbranched polyester grafted titanium dioxide is 1:(0.1-0.2), the product can achieve optimal abrasion resistance and breathability / moisture permeability. The titanium dioxide modified with amide-based dendritic hyperbranched polyester used in Example 1 is more effective than the titanium dioxide modified with other types of hyperbranched polyester used in Examples 8-10. As can be seen from Examples 1 and 11-13, when the formulation ratio of tetrabutyl titanate and EVA resin in the compatibilizer changes, the product's abrasion resistance and breathability / moisture permeability also change. When the ratio is (2:8) to (3:7), the product performance is better.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit the scope of protection of this application. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the substance and scope of the technical solutions of this application.

Claims

1. A white polyethylene fiber film, characterized in that, The flash fiber comprises the following components in parts by weight: 80-85 parts HDPE, 1-3 parts LLDPE, 7-9 parts modified titanium dioxide, 1-3 parts lubricant, and 1-3 parts compatibilizer. In the white polyethylene fiber membrane, LLDPE, modified titanium dioxide, lubricant, and compatibilizer are introduced in the form of masterbatch; The modified titanium dioxide includes hyperbranched polyester grafted modified titanium dioxide; The compatibilizer includes tetrabutyl titanate and EVA resin; The white polyethylene fiber membrane satisfies the following condition: 9.5 ≤ D / B ≤ 20; Where DCN / dtex is the single-bundle fiber strength of the flash fiber, and Bm 2 / g represents the specific surface area of ​​the white polyethylene fiber membrane; The method for preparing the white polyethylene fiber film is characterized by comprising the following steps: Each component is added to a reaction vessel containing a solvent, and then heated and nitrogen gas is introduced to make the temperature inside the reaction vessel greater than or equal to 200°C and less than or equal to 230°C, and the pressure greater than or equal to 10MPa and less than or equal to 12MPa, to obtain a spinning solution. The spinning solution is placed in a flash spinning device for spinning and the film is formed by receiving the fiber film through a receiving device. The resulting fiber film is then cold-pressed and hot-rolled to obtain a white polyethylene film.

2. The white polyethylene fiber film as described in claim 1, characterized in that, The HDPE has a melt index greater than or equal to 5 g / 10 min and less than or equal to 10 g / 10 min at 190 °C and 2.16 kg load, according to ASTM D1238, and / or the LLDPE has a melt index greater than or equal to 10 g / 10 min and less than or equal to 50 g / 10 min at 190 °C and 2.16 kg load, according to ASTM D1238.

3. The white polyethylene fiber film as described in claim 1, characterized in that, The hyperbranched polyester is an amide-based dendritic hyperbranched polyolefin.

4. The white polyethylene fiber film as described in claim 1, characterized in that, The mass ratio of titanium dioxide to hyperbranched polyester in the hyperbranched polyester grafted titanium dioxide is 1:(0.05~0.25).

5. The white polyethylene fiber film as described in claim 1, characterized in that, The lubricant includes at least one of silicone lubricants, amide lubricants, and stearic acid lubricants.

6. The white polyethylene fiber film as described in claim 1, characterized in that, The compatibilizer is a mixture of tetrabutyl titanate and EVA resin; the mass ratio of tetrabutyl titanate to EVA resin is (1:9) to (4:6).

7. The white polyethylene fiber film as described in claim 1, characterized in that, The specific surface area B of the white polyethylene fiber membrane is greater than or equal to 8 m². 2 / g and less than or equal to 15m 2 / g.

8. The white polyethylene fiber film as described in claim 1, characterized in that, The single-bundle fiber strength of the flash fiber is greater than or equal to 130 CN / dtex and less than or equal to 200 CN / dtex.

Images