High-slip and knock-resistant polyester shrink film and preparation method and application thereof

Abstract

The present application relates to a kind of high slick knock-resistant polyester shrink film and its preparation method and application, the method of one-step in-situ preparation of metal phase molybdenum disulfide@graphene ellipsoid hybrid composite material is used, and the composite material is introduced into polyester shrink film matrix, and a kind of high slick knock-resistant polyester shrink film composite material with excellent performance is obtained. With the excellent performance of metal phase molybdenum disulfide and graphene sheet, the preparation of high slick knock-resistant polyester shrink film composite material is realized;The friction coefficient of the high slick knock-resistant polyester shrink film prepared in the application can be reduced to 0.0952, the wear rate can be reduced to 0.229*10 ‑5 mm 3 / Nm, the transmittance does not change significantly after 100 impact tests, and can be widely used in anti-wear, friction-resistant polyester shrink film composite material.

Description

Technical Field

[0001] This invention relates to the field of polyester shrink film technology, specifically to a highly slip-resistant and impact-resistant polyester shrink film with synergistic effects of nanoparticles, its preparation method, and its application. Background Technology

[0002] Polyester materials possess excellent creep resistance, heat resistance, fatigue resistance, impact resistance, and transparency, making them widely used in shrink film materials, bottle flakes, fibers, and engineering plastics. Furthermore, polyester has extensive applications in kitchen appliances, food packaging, and automotive manufacturing, serving as a fundamental material for meeting national economic needs. However, polyester materials have a high abrasion rate, and their transparency heavily relies on surface protection. Their outer surface is very easily worn, causing a significant reduction in transmittance. Therefore, various fillers such as nanoparticles, fibers, and solid lubricants are typically added to polyester materials to obtain composite materials with better mechanical, tribological, and optical properties.

[0003] The use of different fillers to improve the frictional properties of polyester materials has been reported in the literature. For example, Wang Haosheng et al. studied the effects of alumina morphology and particle size on the performance of epoxy-polyester nanocomposite wear-resistant coatings and found that alumina particles of different sizes can improve the wear resistance of the coating. Under the same filler content, the wear rate of the small particle size composite coating is higher than that of the large particle size alumina coating (Chemical New Materials, 2019, 10: 101-104). Mu Qiuhong et al. studied the preparation and wear resistance of unsaturated polyester / sisal fiber composites and found that the wear resistance of the composite material was 68% higher than that of the untreated system; the wear resistance of the composite material improved with the increase of sisal fiber content (Journal of Guilin University of Technology, 2005, 25: 198-201). Although there are reports on the use of nanoparticles or fibers to enhance the wear resistance of polyester, there are few reports on the use of dual nanoparticles to synergistically enhance the wear resistance and impact resistance of polyester. Molybdenum disulfide (MoS2) is widely used in friction materials. Its layered structure and weak interlayer interactions facilitate interlayer slippage, resulting in excellent lubrication properties. MoS2 exists in several phases: 1T, 2H, and 3R. 1T MoS2, also known as metallic MoS2, has a larger interlayer spacing compared to the other two phases, thus promising even better lubrication performance. Current technology typically uses 2H phase MoS2; there are no reports of metallic MoS2 and graphene composites used as high-slip, impact-resistant polyester shrink film materials. Summary of the Invention

[0004] To address the aforementioned issues, the present invention aims to provide a high-slip, impact-resistant polyester shrink film, its preparation method, and its applications. Multiple nanoparticles often exhibit synergistic effects, achieving a synergistic effect greater than the sum of its parts. Therefore, this invention, for the first time, employs a one-step method to prepare a composite material of metallic molybdenum disulfide and graphene. The synergistic effect between nanoparticles is utilized to enhance the high-slip, impact-resistant properties of polyester materials, resulting in a low-cost, simple-to-synthesize polyester composite material with excellent frictional properties. This solves the problem that existing polyester composite materials cannot simultaneously achieve both low preparation costs and good mechanical, frictional, and optical properties.

[0005] The method for preparing a high-slip, impact-resistant polyester shrink film according to the present invention specifically includes the following steps:

[0006] (1) Preparation of metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material: 35-40 ml of distilled water and 5-10 ml of ethanol are mixed evenly to obtain an ethanol solution. Graphene oxide, ammonium molybdate and thiourea are dispersed in the ethanol solution to obtain solution A. Solution A is transferred to a hydrothermal reactor and reacted at 180-200℃ for 16-24 hours. After the reaction is completed, the solution is cooled to room temperature. The solution after the reaction is filtered through a cellulose filter membrane. The solid obtained by filtration is dried to obtain the metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material.

[0007] (2) Take the metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) and the polyester matrix as raw materials, add them to a high-speed mixer for mixing, and then transfer them to a twin-screw extruder for melt blending, extrusion granulation, and injection molding to obtain a high-slip and impact-resistant polyester shrink film composite material.

[0008] Furthermore, in step (1), the mass of graphene oxide is 0.10g, the mass of ammonium molybdate is 1.25g, and the mass of thiourea is 1.00g.

[0009] Furthermore, the polyester matrix mentioned in step (2) is one or more of polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polybutylene adipate, and polybutylene succinate. This metal-phase molybdenum disulfide@graphene ellipsoidal hybrid composite material can be widely used in other polyester materials.

[0010] Furthermore, in step (2), the mass of the metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material accounts for 1-5% of the total mass of the raw materials.

[0011] Furthermore, in step (2), the mixing time of the raw materials in the high-speed mixer is 10 minutes.

[0012] Furthermore, in step (2), the melt blending time is 2-8 minutes, and the extrusion granulation temperature is 200-240℃.

[0013] Furthermore, in step (2), the injection molding pressure is 80 MPa and the injection molding temperature is 240 °C.

[0014] Furthermore, the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) has an ellipsoidal morphology. By changing the reaction conditions, nanomaterials with other morphologies and structures can be obtained, as described in the background section.

[0015] In step (1), a distilled water-ethanol mixed solvent is used as the reaction solvent, and thiourea is used as the reducing agent. The introduction of ethanol plays a decisive role in the morphology of the product. Using other solvents and reducing agents will yield nanomaterials with different structures and morphologies. For example, molybdenum disulfide, which is widely reported, usually uses thioacetamide as the reducing agent and distilled water as the solvent, and usually yields 2H phase molybdenum disulfide.

[0016] The present invention also provides a high-slip and impact-resistant polyester shrink film composite material obtained by the above preparation method and the application of the high-slip and impact-resistant polyester shrink film composite material in the field of shrink film materials.

[0017] The high smoothness and impact resistance of this composite material are achieved through the synergistic effect of nanoparticles.

[0018] In this invention, flexible, sheet-like graphene sheets and rigid molybdenum disulfide sheets adsorb onto each other to form an ellipsoidal composite material. The use of ethanol solvent significantly affects the morphology of the molybdenum disulfide@graphene composite material; the key to forming the metallic molybdenum disulfide phase is the hydrothermal temperature and time. The metallic molybdenum disulfide@graphene obtained in this application exhibits an ellipsoidal morphology, as shown below. Figure 1 As shown, graphene sheets and the metallic molybdenum disulfide adsorb each other. Under the shearing action of the friction surface, the overlapping graphene and molybdenum disulfide sheets are peeled off and then adsorbed onto the surface of the friction pair to form a protective film.

[0019] This invention discloses a method for preparing a high-slip, impact-resistant polyester shrink film composite material. First, a molybdenum disulfide@graphene ellipsoidal hybrid composite material is prepared using a one-step hydrothermal method. Then, this composite material is introduced into a polyester matrix, creating "micro-bearings" on the friction surface, resulting in a polyester composite material with excellent frictional properties. Under the enormous shear force of the friction surface, the molybdenum disulfide@graphene ellipsoidal hybrid composite material undergoes exfoliation, effectively dispersing the load while obtaining monolayers of molybdenum disulfide and graphene sheets. These monolayer materials are adsorbed onto the friction surface, forming a protective film. The high slip resistance is reflected in the low coefficient of friction of the polyester composite material; the impact resistance is reflected in its good wear resistance. Improved wear resistance reduces surface scratches on the polyester shrink film, thereby enhancing the optical performance of the composite material under different service conditions.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) This invention relates to a high-slip, impact-resistant polyester shrink film composite material with synergistic nanoparticle effects and its preparation method. The metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material with synergistic wear-resistant enhancement is composited in situ using a one-step hydrothermal method, resulting in a simple preparation process. This composite material is then incorporated into a polyester matrix to obtain an anti-wear and wear-resistant composite material. Graphene sheets readily form a physical protective film, while molybdenum disulfide sheets readily form a chemical protective film. Under the synergistic effect of these dual protective films, the friction performance of the friction pair is significantly improved. Under the enormous shear force of the friction surface, the metallic molybdenum disulfide and graphene undergo relative slippage. The exfoliated molybdenum disulfide and graphene sheets are adsorbed onto the friction surface, forming a chemical friction film, which greatly reduces polyester wear. Simultaneously, the ellipsoidal composite material can form "micro-bearings" on the friction surface, bearing loads and improving tribological properties. Finally, the added nanoparticles can reduce the surface energy of the material, reduce interfacial interaction forces, and improve the optical properties of the material after multiple impacts. The friction coefficient of the polyester composite material obtained by this invention can be reduced from 0.258 for pure polyester to 0.0952, and the wear rate can be reduced from 0.350 × 10⁻⁶ for pure polyester. -5 mm 3 / N m can be reduced to 0.229×10 -5 mm 3 / Nm, after the impact test of the polyester shrink film material, its optical transmittance still remained above 98%, and after 100 impact tests, the transmittance did not change significantly.

[0022] (2) The present invention prepares molybdenum disulfide@graphene in a one-step process. The route is simple, the sheet has a large specific surface area, and it is easy to be adsorbed on the friction surface. It can greatly increase the friction performance of polyester and also has significant economic benefits. The method of the present invention is simple, low cost, and easy to realize large-scale industrial production. It has significant economic benefits and can be widely used in the field of high slip resistance and impact resistance polyester shrink film composite materials. It has broad application prospects. Attached Figure Description

[0023] Figure 1 This is a morphology diagram of the ellipsoidal metallic phase molybdenum disulfide@graphene obtained in Example 1 of this invention;

[0024] Figure 2 This is a wear surface morphology diagram of the high-slip and impact-resistant polyester shrink film prepared in Example 1 of the present invention;

[0025] Figure 3 The image shows the wear surface morphology of the high-slip, impact-resistant polyester shrink film prepared for Comparative Example 2. Detailed Implementation

[0026] To better understand the content of this invention, it will be further described below with reference to specific embodiments and accompanying drawings. The following embodiments are based on the technology of this invention and provide detailed implementation methods and operating steps, but the scope of protection of this invention is not limited to the following embodiments.

[0027] The ethanol used in the examples and comparative examples was analytical grade ethanol.

[0028] Example 1:

[0029] (1) Mix 40 ml of distilled water and 5 ml of ethanol evenly to obtain an ethanol solution. Disperse 0.10 g of graphene oxide, 1.25 g of ammonium molybdate and 1.00 g of thiourea in the ethanol solution to obtain solution A. Transfer solution A to a hydrothermal reactor and react at 200 °C for 20 hours. After the reaction is completed, cool to room temperature. Filter the solution after the reaction through a cellulose filter membrane. Dry the solid obtained by filtration to obtain a metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material.

[0030] (2) Take 5 parts by weight of the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) and 95 parts by weight of polyester particles, add them to a high-speed mixer and mix for 10 minutes. Then transfer them to a twin-screw extruder for melt blending, extrusion granulation and injection molding to obtain a high-slip and impact-resistant polyester shrink film. The melt blending time in the twin-screw extruder is 6 minutes, the extrusion granulation temperature is 220℃, the injection molding pressure is 80MPa and the injection molding temperature is 240℃. The polyester particles are polyethylene terephthalate particles.

[0031] Example 2:

[0032] (1) This step is the same as step (1) in Example 1;

[0033] (2) Take 4 parts by weight of the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) and 96 parts by weight of polyester particles, add them to a high-speed mixer and mix for 10 minutes. Then transfer them to a twin-screw extruder for melt blending, extrusion granulation and injection molding to obtain a high-slip and impact-resistant polyester shrink film. The melt blending time in the twin-screw extruder is 6 minutes, the extrusion granulation temperature is 220℃, the injection molding pressure is 80MPa and the injection molding temperature is 240℃. The polyester particles are polybutylene terephthalate particles.

[0034] Example 3:

[0035] (1) This step is the same as step (1) in Example 1;

[0036] (2) Take 3 parts by weight of the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) and 97 parts by weight of polyester particles, add them to a high-speed mixer and mix for 10 minutes. Then transfer them to a twin-screw extruder for melt blending, extrusion granulation and injection molding to obtain a high-slip and impact-resistant polyester shrink film. The melt blending time in the twin-screw extruder is 6 minutes, the extrusion granulation temperature is 220℃, the injection molding pressure is 80MPa and the injection molding temperature is 240℃. The polyester particles are polypropylene terephthalate particles.

[0037] Example 4:

[0038] (1) This step is the same as step (1) in Example 1;

[0039] (2) Take 1 part by weight of the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) and 99 parts by weight of polyester particles, add them to a high-speed mixer and mix for 10 minutes. Then transfer them to a twin-screw extruder for melt blending, extrusion granulation and injection molding to obtain a high-slip and impact-resistant polyester shrink film. The melt blending time in the twin-screw extruder is 2 minutes, the extrusion granulation temperature is 220℃, the injection molding pressure is 80MPa and the injection molding temperature is 240℃. The polyester particles are polybutylene terephthalate particles.

[0040] Comparative Example 1:

[0041] Take 100 parts by weight of polyester granules, add them to a high-speed mixer and mix for 10 minutes. Then transfer them to a twin-screw extruder for melt blending, extrusion granulation, and injection molding to obtain a high-slip and impact-resistant polyester shrink film composite material. The melt blending time in the twin-screw extruder is 6 minutes, the extrusion granulation temperature is 220℃, the injection molding pressure is 80MPa, and the injection molding temperature is 240℃.

[0042] Comparative Example 2:

[0043] (1) 0.10 g graphene oxide, 1.25 g ammonium molybdate and 1.00 g thiourea were dispersed in 50 mL of distilled aqueous solution to obtain solution B. Solution B was transferred to a hydrothermal reactor and reacted at 200 °C for 20 hours. After the reaction was completed, the solution was cooled to room temperature. The solution after the reaction was filtered through a cellulose filter membrane. The solid obtained by filtration was dried to obtain a conventional 2H molybdenum disulfide@graphene hybrid composite material.

[0044] (2) Take 5 parts by weight of the 2H molybdenum disulfide@graphene hybrid composite material obtained in step (1) and 95 parts by weight of polyester particles, add them to a high-speed mixer and mix for 10 minutes. Then transfer them to a twin-screw extruder for melt blending, extrusion granulation and injection molding to obtain a high-slip and impact-resistant polyester shrink film composite material. The melt blending time in the twin-screw extruder is 6 minutes, the extrusion granulation temperature is 220℃, the injection molding pressure is 80MPa and the injection molding temperature is 240℃.

[0045] The tribological properties of a high-slip, impact-resistant polyester shrink film were tested using an MM-W1 four-ball friction testing machine. The friction and wear test conditions were 1.648 GPa and 1000 rpm, with a test time of 30 minutes. The steel balls were GCr15 bearing steel (diameter: 12.7 mm). Three repeated friction and wear tests were conducted under the experimental conditions, and the average value of the performance data obtained from the three repeated tests was taken.

[0046] Table 1. Performance of the high-slip, impact-resistant polyester shrink films prepared in Examples 1-4 and Comparative Examples 1-2.

[0047]

[0048] As shown in Table 1, the addition of a molybdenum disulfide@graphene ellipsoidal hybrid composite material to the polyester matrix can significantly improve the frictional properties of the polyester. In Example 1, the addition ratio of the molybdenum disulfide@graphene ellipsoidal hybrid composite material was 5% of the polyester. In Examples 1-4, as the addition amount of the molybdenum disulfide@graphene ellipsoidal hybrid composite material increased, the friction coefficient of the polyester composite material gradually decreased, and the wear rate also showed a decreasing trend, that is, the wear resistance gradually improved. At the same time, it can also be found that as the content of the molybdenum disulfide@graphene ellipsoidal hybrid composite material continued to increase, the rate of improvement of the wear resistance of the polyester composite material slowed down. This may be because when the concentration of the molybdenum disulfide@graphene ellipsoidal hybrid composite material increases, a small amount of exfoliated molybdenum disulfide and graphene sheets agglomerate, resulting in a slowdown in the rate of improvement of wear resistance.

[0049] When the weight percentage of the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material in the polyester composite material is 5%, the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material is exfoliated under the shearing action of the friction surface, generating free molybdenum disulfide sheets and graphene sheets. Due to the large specific surface area of ​​these sheets, they are easily adsorbed on the friction surface of the friction pair, thus forming a physical and chemical protective film, thereby reducing the friction coefficient and wear rate, exhibiting the best wear resistance performance. If the content of the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material is further increased, the exfoliated molybdenum disulfide and graphene sheets are prone to agglomeration. Therefore, as the content of the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material increases, the rate of increase in wear resistance slows down. From the above data, it can be seen that the prepared metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material has good lubrication performance, and adding a small amount (about 2%) can significantly improve the friction performance of the polyester composite material. Therefore, the prepared metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material is a good solid lubricant additive and can be used as a wear-resistant agent for polyester materials. Comparative Example 2 shows that, compared with 2H phase molybdenum disulfide nanomaterials, metallic molybdenum disulfide nanocomposite materials have superior tribological properties. The prepared polyester film material was horizontally fixed on a mold, and a steel ball (6.35 mm) was dropped freely from a height of 1 meter. The light transmittance of the polyester shrink film after 100 impacts by the ball was tested to characterize its impact resistance. As shown in Table 1, unlike the comparative example, the light transmittance of the shrink film material in the example material significantly increased after the ball impact as the coefficient of friction of the polyester shrink film decreased and the wear resistance improved, indicating that the shrink film prepared in this application has good impact resistance.

[0050] Figure 1 This is a morphology image of the ellipsoidal metallic phase molybdenum disulfide@graphene obtained in Example 1 of this invention; from Figure 1 It can be seen that the soft graphene sheets are combined with the rigid metallic phase molybdenum disulfide, and the two form a unique ellipsoidal morphology.

[0051] Figure 2 This is a wear surface morphology image of the high-slip, impact-resistant polyester shrink film composite material prepared in Example 1 of the present invention. Figure 2 It is known that the metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material is uniformly dispersed in the matrix, thus providing good anti-wear and friction-reducing properties on the friction surface.

[0052] Figure 3 The image shows the wear surface morphology of the high-slip, impact-resistant polyester shrink film composite material prepared in Comparative Example 2. Figure 3 It can be seen that the composite material exhibited obvious tearing behavior, which indirectly reflects the excellent friction properties of the high-slip and impact-resistant polyester shrink film composite material prepared by the metallic molybdenum disulfide@graphene hybrid composite material.

[0053] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a highly slippery and impact-resistant polyester shrink film, characterized in that, Specifically, the following steps are included: (1) Preparation of metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material: Mix 35-40 ml of distilled water and 5-10 ml of ethanol evenly to obtain an ethanol solution. Disperse graphene oxide, ammonium molybdate and thiourea in the ethanol solution to obtain solution A. Transfer solution A to a hydrothermal reactor and react at 180-200℃ for 16-24 hours. After the reaction is completed, cool to room temperature. Filter the solution after the reaction through a cellulose filter membrane. Dry the solid obtained by filtration to obtain metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material. (2) Take the metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) and the polyester matrix as raw materials, add them to a high-speed mixer for mixing, and then transfer them to a twin-screw extruder for melt blending, extrusion granulation, and injection molding to obtain a high-slip and impact-resistant polyester shrink film.

2. The method for preparing the high-slip, impact-resistant polyester shrink film as described in claim 1, characterized in that, In step (1), the mass of graphene oxide is 0.10 g, the mass of ammonium molybdate is 1.25 g, and the mass of thiourea is 1.00 g.

3. The method for preparing the high-slip, impact-resistant polyester shrink film as described in claim 1, characterized in that, The polyester matrix mentioned in step (2) is one or more of polybutylene terephthalate, polyethylene terephthalate, polypropylene terephthalate, polybutylene adipate, and polybutylene succinate.

4. The method for preparing the high-slip, impact-resistant polyester shrink film as described in claim 1, characterized in that, In step (2), the mass of the metal phase molybdenum disulfide@graphene ellipsoidal hybrid composite material accounts for 1-5% of the total mass of the raw materials.

5. The method for preparing the high-slip, impact-resistant polyester shrink film as described in claim 1, characterized in that, In step (2), the mixing time of the raw materials in the high-speed mixer is 10 minutes.

6. The method for preparing the high-slip, impact-resistant polyester shrink film as described in claim 1, characterized in that, In step (2), the melt blending time is 2-8 minutes, and the extrusion granulation temperature is 200-240℃.

7. The method for preparing the high-slip, impact-resistant polyester shrink film as described in claim 1, characterized in that, In step (2), the injection molding pressure is 80 MPa and the injection molding temperature is 240℃.

8. The method for preparing the high-slip, impact-resistant polyester shrink film as described in claim 1, characterized in that, The metallic molybdenum disulfide@graphene ellipsoidal hybrid composite material obtained in step (1) has an ellipsoidal morphology.

9. A highly slip-resistant and impact-resistant polyester shrink film prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the high-slip, impact-resistant polyester shrink film as described in claim 9 in the field of shrink film materials.

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