High-strength wear-resistant PET plastic steel packing belt and preparation process thereof

Abstract

The application provides a high-strength wear-resistant PET plastic steel packing belt and a preparation process thereof, and relates to the field of packing belt materials.The packing belt comprises a core layer, a transition layer, a bearing layer and a wear-resistant layer which are sequentially arranged from inside to outside.The core layer is prepared from a first PET matrix, glass fibers and a coupling agent;the transition layer is prepared from a second PET matrix grafted with maleic anhydride;the bearing layer is prepared from a third PET matrix with high viscosity and nano-aluminum oxide particles;and the wear-resistant layer is prepared from a fourth PET matrix, polytetrafluoroethylene micro powder and molybdenum disulfide.The strength and high-temperature resistance of the whole are enhanced, and the wear resistance is optimized.

Description

Technical Field

[0001] This invention relates to the field of packaging strap materials, and more specifically, to a high-strength, wear-resistant PET plastic-steel strapping and its preparation process. Background Technology

[0002] With the rapid development of the logistics industry, the performance requirements for strapping used to bundle goods are becoming increasingly stringent. However, existing PET plastic strapping has certain shortcomings in terms of strength and abrasion resistance, and cannot meet the needs of certain special industries and harsh environments.

[0003] First, in terms of material strength, traditional strapping has relatively weak tensile strength and impact resistance, making it prone to breakage or loosening during transportation and handling, thus failing to provide stable and reliable fixation for goods. Second, in terms of weather resistance, traditional strapping has poor adaptability to environmental factors such as temperature and humidity, and is prone to embrittlement and deformation in harsh environments, affecting its service life and packaging effectiveness. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength and wear-resistant PET plastic steel strapping and its preparation process, which can enhance the overall strength and high-temperature resistance of the strapping and optimize its wear resistance.

[0005] The embodiments of the present invention are implemented as follows:

[0006] This application provides a high-strength, wear-resistant PET plastic-steel strapping, comprising a core layer, a transition layer, a load-bearing layer, and a wear-resistant layer stacked sequentially from the inside out.

[0007] The core layer is made of a first PET matrix, glass fiber and coupling agent;

[0008] The transition layer is obtained by grafting maleic anhydride onto a second PET matrix;

[0009] The carrier layer is made of a high-viscosity third PET matrix and nano-alumina particles;

[0010] The wear-resistant layer is made of a fourth PET matrix, polytetrafluoroethylene micro powder and molybdenum disulfide.

[0011] Furthermore, based on the aforementioned scheme, and calculated by quality score:

[0012] The core layer comprises 64-80% first PET matrix, 15-30% glass fiber, and 5% coupling agent;

[0013] The carrier layer comprises 95-98% third PET matrix and 2-5% nano-alumina particles;

[0014] The wear-resistant layer comprises 82-87% of a fourth PET matrix, 10-15% of polytetrafluoroethylene micro powder, and 3% of molybdenum disulfide.

[0015] Furthermore, based on the aforementioned scheme, the grafting rate of maleic anhydride in the transition layer is 0.5-1.2%.

[0016] Furthermore, based on the aforementioned scheme, the coupling agent includes titanate esters.

[0017] Furthermore, based on the aforementioned scheme, the viscosity value of the third PET matrix is ​​0.95 dl / g;

[0018] The alumina nanoparticles have a particle size of 50 nm.

[0019] The particle size of the polytetrafluoroethylene micro powder is 10 μm.

[0020] Furthermore, based on the aforementioned scheme, the thickness ratio of the core layer: transition layer: bearing layer: wear-resistant layer is 5:2:2:1.

[0021] A manufacturing process for a high-strength, wear-resistant PET plastic-steel strap as described above includes the following steps:

[0022] The core layer, transition layer, load-bearing layer, and wear-resistant layer are prepared separately and then dried.

[0023] The core layer, transition layer, load-bearing layer and wear-resistant layer are respectively fed into a five-stage screw-type co-extrusion equipment for extrusion molding to form a multi-layered packing strap blank; wherein, the core layer introduces a two-stage vacuum degassing section, and the transition layer introduces a dynamic cross-linking temperature control section;

[0024] The packing strap blank is subjected to stretching and shaping treatment;

[0025] The stretched packing strap blank is rapidly cooled and shaped.

[0026] The surface treatment of the cooled and shaped packing strap blank is carried out to obtain the finished packing strap.

[0027] Furthermore, based on the aforementioned scheme, the stretching and shaping process of the packing strap blank adopts a stepped heating method; wherein, the first stage temperature is 70℃ and maintained for 3-5 minutes, and the second stage temperature is 110℃ and maintained for 8-10 minutes.

[0028] Furthermore, based on the aforementioned scheme, the step of feeding the core layer, transition layer, bearing layer and wear-resistant layer into a five-stage screw partition co-extrusion equipment for extrusion molding further includes: applying high-frequency ultrasonic vibration for 4-6 seconds after extrusion.

[0029] Furthermore, based on the aforementioned scheme, the surface treatment includes grinding and polishing.

[0030] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects:

[0031] This application utilizes a four-layer structure for the plastic-steel strapping. The core layer is made of glass fiber reinforced PET, combined with a compatibilizing transition layer grafted with maleic anhydride onto the PET. This layer forms coordination bonds with the coupling agent in the core layer, which enhances the interfacial chemical bonding strength and significantly increases the bending strength. The load-bearing layer induces shear yielding through nano-alumina particles. The wear-resistant layer is composed of polytetrafluoroethylene (PTFE) micropowder and molybdenum disulfide incorporated into the PET matrix. The PTFE micropowder reduces the coefficient of friction, while the molybdenum disulfide synergistically improves high-temperature lubricity, forming a low-friction, high-temperature resistant surface layer that reduces wear. The synergistic effect produced by the specific combination of these four layers not only enhances the overall strength and high-temperature resistance but also optimizes the wear resistance. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic cross-sectional view of the high-strength and wear-resistant PET plastic-steel strapping according to an embodiment of the present invention;

[0034] Figure 2 This is a flowchart illustrating the manufacturing process of the packing tape according to an embodiment of the present invention.

[0035] Icons: 1-Core layer, 2-Transition layer, 3-Bearing layer, 4-Wear-resistant layer. Detailed Implementation

[0036] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0037] Please refer to Figure 1 The image shows a schematic diagram of a high-strength, wear-resistant PET plastic-steel strapping.

[0038] This embodiment provides a high-strength, wear-resistant PET plastic-steel strapping, comprising a core layer 1, a transition layer 2, a load-bearing layer 3, and a wear-resistant layer 4, which are stacked sequentially from the inside out.

[0039] The core layer 1 is made of a first PET matrix, glass fiber and coupling agent;

[0040] Transition layer 2 is obtained by grafting maleic anhydride onto the second PET matrix;

[0041] The carrier layer 3 is made of a high-viscosity third PET matrix and nano-alumina particles;

[0042] The wear-resistant layer 4 is made of a fourth PET matrix, polytetrafluoroethylene micro powder and molybdenum disulfide.

[0043] The following will further describe a high-strength, wear-resistant PET plastic-steel strapping according to this exemplary embodiment.

[0044] In some embodiments, the aforementioned packing strap is composed of a four-layer composite structure. The core layer 1, by mass fraction, comprises 64-80% PET matrix, 15-30% glass fiber, and 5% coupling agent. The PET matrix is ​​reinforced with glass fiber, which serves as a continuous phase providing basic strength. The total proportion of glass fiber and coupling agent is 20-36%, ensuring uniform fiber dispersion and collectively increasing the flexural strength of the PET matrix. As the core layer 1 of the packing strap, it possesses high flexural strength and enhances overall strength.

[0045] Transition layer 2 is obtained by grafting maleic anhydride onto the second PET matrix. No additional filler is used; carboxylic acid groups are introduced through chemical grafting at a rate of 0.5-1.2%, forming coordination bonds with the coupling agent in core layer 1 to enhance the interfacial chemical bonding strength.

[0046] Preferably, the coupling agent includes titanate esters. The selection of titanate esters as coupling agents, rather than conventional silanes, enables them to form coordination bonds with maleic anhydride-grafted PET, resulting in an interlayer peel strength of 45 N / cm, thereby improving the overall strength.

[0047] The support layer 3, by mass fraction, comprises 95-98% of a third PET matrix and 2-5% of nano-alumina particles. The viscosity value IV of the third PET matrix is ​​0.95 dl / g, and its high viscosity allows the nano-alumina particles to adhere stably to the matrix. The nano-alumina particles have a particle size of 5 nm and, as an antioxidant, can induce shear bands and delay crack propagation, thereby improving the strength of the support layer 3.

[0048] The wear-resistant layer 4, by mass fraction, comprises 82-87% PET matrix, 10-15% polytetrafluoroethylene (PTFE) micropowder, and 3% molybdenum disulfide. The PTFE micropowder has a particle size of 10 μm. Its addition to the matrix reduces the coefficient of friction, while the molybdenum disulfide synergistically enhances high-temperature lubricity, forming a low-friction, high-temperature resistant surface layer. This reduces the frictional energy consumption between the strapping and the equipment, thereby reducing wear.

[0049] In a preferred embodiment, the thickness ratio of the core layer 1: transition layer 2: bearing layer 3: abrasion-resistant layer 4 is 5:2:2:1. The core layer 1, as the base layer, has a larger thickness, providing higher strength. The transition layer 2 and bearing layer 3 are thinner than the core layer 1 but thicker than the outermost abrasion-resistant layer 4, synergistically improving the flexural strength, shear strength, and interfacial reinforcement of the strapping. The abrasion-resistant layer 4 optimizes the abrasion resistance of the strapping, thus forming a high-strength, high-abrasion-resistant strapping.

[0050] Beneficial effects of this embodiment:

[0051] Core layer 1 high strength: a high glass fiber content (25-30%) meets the bending resistance requirements, and a low-density titanate coupling agent is selected (compared to silane coupling agent) to reduce weight.

[0052] Transition layer 2 compatibility enhancement: Pure grafted PET avoids impurities interfering with interface bonding, solving the problem of poor compatibility between recycled materials and glass fiber.

[0053] 3. Toughness of the bearing layer: The proportion of nano-alumina is <5% to prevent agglomeration and ensure the processability of PET.

[0054] Wear-resistant layer 4 energy saving: High lubricating additives reduce the energy consumption of friction between the packing strap and the equipment (actual measurement shows a 68% reduction in transport wear).

[0055] Reference Figure 2 This application also provides a manufacturing process for the high-strength, wear-resistant PET plastic-steel strapping as described above, comprising the following steps:

[0056] S110. Prepare the core layer 1, transition layer 2, load-bearing layer 3 and wear-resistant layer 4 respectively, and perform drying treatment;

[0057] S120, the core layer 1, transition layer 2, bearing layer 3 and wear-resistant layer 4 are respectively fed into a five-stage screw partition co-extrusion equipment for extrusion molding to form a multi-layer structured packing strip blank; wherein, the core layer 1 is introduced into a two-stage vacuum degassing section, and the transition layer 2 is introduced into a dynamic cross-linking temperature control section.

[0058] S130. Stretch and shape the packing strap blank;

[0059] S140. Rapidly cool and shape the stretched packing strap blank.

[0060] S150. Surface treatment is performed on the cooled and shaped packing strap blank to obtain the finished packing strap.

[0061] In a preferred embodiment, the preparation of core layer 1 in step S110 specifically includes: drying the first PET matrix at 120-140℃ for 4-6 hours to ensure a moisture content ≤0.02%. Cutting glass fibers into 3-5mm short fibers and impregnating the surface with a titanate coupling agent (the amount of coupling agent is 1-2% of the fiber mass). Adding the dried PET matrix (64-80%), the treated glass fibers (15-30%), and the remaining coupling agent (5% of the total system) to a high-speed mixer in proportion, and mixing for 10-15 minutes. The mixture is then melt-blended in a twin-screw extruder (temperature range 240-260℃), with a screw speed of 200-300 rpm, to ensure uniform fiber dispersion. The extruded strip is water-cooled and then pelletized, with the pellets undergoing secondary drying (100℃ / 2 hours).

[0062] The preparation of transition layer 2 specifically includes: adding PET resin, maleic anhydride (mass ratio 100:0.5-1.2), and dicumyl peroxide (DCP, initiator, 0.1-0.3%) to a reactor, heating to 260-270℃ under nitrogen protection, and reacting for 20-30 minutes to achieve maleic anhydride grafting. After the reaction, the melt is solvent-extracted to remove unreacted monomers, then vacuum dehydrated and dried for purification. The modified PET is granulated using a single-screw extruder (temperature 240-250℃), cooled, and stored in a dry environment.

[0063] The preparation of the support layer 3 specifically includes mixing nano-alumina (50nm) with an ethanol solution of silane coupling agent (KH-550), ultrasonically treating for 1 hour, drying at 80℃, and performing surface modification. High-viscosity PET (IV value 0.95 dl / g) and modified alumina (2-5%) are premixed and then high-temperature sheared dispersed using a twin-screw extruder (temperature 260-275℃, screw speed 150-200 rpm).

[0064] The preparation of wear-resistant layer 4 specifically includes drying the fourth PET matrix at 120℃ for 6 hours to achieve a moisture content ≤0.03%. Polytetrafluoroethylene (PTFE) micropowder and molybdenum disulfide (MoS2) are premixed in a ball mill for 2 hours (300 rpm). PET (82-87%), PTFE (10-15%), and MoS2 (3%) are added to an internal mixer and mixed at 180-200℃ for 15 minutes. The mixture is then extruded using a single-screw extruder (temperature 240-250℃).

[0065] In a preferred embodiment, in step S120 above, the core layer 1, transition layer 2, bearing layer 3, and wear-resistant layer 4 are respectively fed into a five-stage screw-type co-extrusion equipment for extrusion molding. During extrusion, 50Hz high-frequency ultrasonic vibration is applied for 4-6 seconds to form a multi-layered packing tape blank. The core layer 1 incorporates a two-stage vacuum degassing section, including a coarse degassing stage: after the polymer material of the core layer 1 melts in the 80-120℃ temperature range, it enters a low-pressure vacuum section (-0.06MPa) to remove free bubbles; and a second-stage vacuum strengthening stage: pressurizing to -0.09MPa for secondary degassing to eliminate micropores inside the melt, with surface bubble residue ≤0.03%. The transition layer 2 incorporates a dynamic cross-linking temperature control section, i.e., the transition layer 2 enters a 185-195℃ temperature control section, combining continuous shear force and stepped heating (temperature difference ≤5℃ per stage). The high-speed shearing of the screw (120-150 rpm) triggers the activity of molecular chains, and dynamic cross-linking network construction is achieved by combining free radical grafting. That is, the dynamic cross-linking reaction is completed by the screw shearing force and thermal activation, which enhances the interface.

[0066] It should be noted that when 50Hz high-frequency ultrasonic vibration is applied during extrusion, the nano-alumina is oriented under ultrasonic vibration, and the longitudinal tensile modulus is increased to 9.8GPa, forming a three-dimensional force transmission network.

[0067] As a preferred implementation, in step S130 above, the stretching and shaping process of the packing strap blank adopts a stepped heating method; specifically, a two-stage heating method is adopted, wherein the first stage temperature is 70°C and maintained for 3-5 minutes, and the second stage temperature is 110°C and maintained for 8-10 minutes, so as to improve the strength of the packing strap.

[0068] As a preferred implementation, in step S140 above, the stretched packing strap blank is rapidly cooled and shaped. This can be achieved by using a water tank for rapid cooling, placing the packing strap blank in a water tank for rapid cooling; or by using forced air cooling, employing an air cooler to rapidly cool the packing strap blank.

[0069] As a preferred implementation method, in step S150 above, the cooled and shaped packing strap blank is ground and polished to obtain the finished packing strap, thereby improving the surface smoothness and wear resistance.

[0070] It should be noted that, with the assistance of specific materials and manufacturing processes, the aforementioned layers can form an interpenetrating network structure at the interlayer interface, enhancing the connection strength of each layer. Specifically, the transition layer 2 is provided with maleic anhydride-grafted PET (MAH-PET). When it comes into contact with the glass fiber-reinforced PET of the core layer 1, the alkoxy groups of the titanate coupling agent coordinate with the carboxyl groups of MAH to generate a Ti-O-CO-R network cross-linked structure. The grafted chains penetrate the core layer 1 to form dendritic fractal interpenetration of 0.06±0.01 mm, thereby enhancing the interfacial strength. Furthermore, during multilayer co-extrusion, ultrasonic vibration (50 kHz) causes the nano-alumina particles to generate a cavitation effect during extrusion, breaking through the interlayer interface and forming micropores with a diameter of 10-50 μm. The surface polytetrafluoroethylene (PTFE) micropowder melt forms a mushroom-shaped anchoring structure through the pores, forming an interpenetrating structure with the load-bearing layer 3, further enhancing the interfacial strength.

[0071] To verify the technical effect of the present invention, the PET plastic-steel strapping prepared by the present invention was subjected to performance tests, and the test data are as follows:

[0072] Furthermore, unless otherwise explicitly specified or limited, the terms "installation" and "connection" in this application embodiment should be interpreted broadly. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. The terms "upper," "lower," "left," "right," "inner," "outer," and "side," etc., are merely for reference to the direction in the accompanying drawings or the usual placement of the product during use. They are only for clearly describing this application and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. They should not be construed as limitations on this application. The terms "first," "second," etc., are only used for distinguishing descriptions and should not be construed as indicating or implying relative importance; "multiple" refers to at least two. In this application embodiment, the limitations on relative positional relationships such as parallel, perpendicular, and aligned are all relative to the current technological level and are not absolutely strict limitations. Slight deviations are allowed; approximations of parallel, perpendicular, and aligned are all acceptable. For example, "A and B are parallel" means that A and B are parallel or approximately parallel, and the angle between A and B can be between 0 degrees and 10 degrees.

[0073] The above are only some embodiments and implementation methods of this application. The protection scope of this application is not limited thereto. In the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other. Any combination of features in different embodiments is also within the protection scope of this application. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A high strength wear resistant PET plastic steel strapping characterized in that, The core layer, the transition layer, the bearing layer and the wear-resistant layer are sequentially stacked from inside to outside, The core layer is made of a first PET matrix, glass fibers and a coupling agent; the first PET matrix accounts for 64-80%, the glass fibers account for 15-30% and the coupling agent accounts for 5% by mass fraction; wherein the coupling agent comprises a titanate; The transition layer is made of maleic anhydride grafted to a second PET matrix; wherein the grafting rate of maleic anhydride is 0.5-1.2%; The bearing layer is made of a third PET matrix with high viscosity and nano-aluminum oxide particles; the third PET matrix accounts for 95-98% and the nano-aluminum oxide particles account for 2-5% by mass fraction; The wear-resistant layer is made of a fourth PET matrix, polytetrafluoroethylene micro-powder and molybdenum disulfide; the fourth PET matrix accounts for 82-87%, the polytetrafluoroethylene micro-powder accounts for 10-15% and the molybdenum disulfide accounts for 3% by mass fraction.

2. The high strength abrasion resistant PET plastic steel strapping of claim 1, wherein, The viscosity value of the third PET matrix is 0.95 dl / g; The particle size of the nano-aluminum oxide particles is 50 nm; The particle size of the polytetrafluoroethylene micro-powder is 10 μm.

3. The high strength abrasion resistant PET plastic steel strapping of claim 1, wherein, The thickness ratio of the core layer, the transition layer, the bearing layer and the wear-resistant layer is 5:2:2:

1.

4. A process for the preparation of high strength abrasion resistant PET plastic steel strapping as claimed in any one of claims 1 to 3, wherein, The method comprises the following steps: Preparation of the core layer, the transition layer, the bearing layer and the wear-resistant layer, and drying treatment; The core layer, the transition layer, the bearing layer and the wear-resistant layer are respectively sent into a five-stage screw partition co-extrusion equipment for extrusion molding to form a multi-layer structure of the baling belt blank; wherein the core layer is introduced into a double-stage vacuum degassing section, and the transition layer is introduced into a dynamic crosslinking temperature control section; Stretching and setting treatment of the baling belt blank; Rapid cooling and setting of the stretched baling belt blank; Surface treatment of the cooled and set baling belt blank to obtain a baling belt finished product.

5. The manufacturing process according to claim 4, characterized in that, The stretching and setting treatment of the baling belt blank adopts stepwise temperature rising; wherein the first stage temperature is 70℃ for 3-5 min, and the second stage temperature is 110℃ for 8-10 min.

6. The manufacturing process of claim 4, wherein, The step of respectively sending the core layer, the transition layer, the bearing layer and the wear-resistant layer into the five-stage screw partition co-extrusion equipment for extrusion molding further comprises: applying high-frequency ultrasonic vibration for 4-6 seconds after extrusion.

7. The manufacturing process of claim 4, wherein, The surface treatment comprises polishing treatment and polishing treatment.

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