High-temperature-resistant PP honeycomb tube and preparation method and application thereof

Abstract

The application discloses a high-temperature-resistant PP honeycomb tube and a preparation method and application thereof. The high-temperature-resistant PP honeycomb tube is composed of a plurality of PP tubes which are fixedly bonded into an integrated whole. The PP tube has an inner diameter of 3-10 mm and a wall thickness of 0.1-1 mm. The PP tube comprises a tube body and a bonding film layer arranged on the surface of the tube body. The tube body comprises the following components: PP resin, wherein the melt index of the PP resin under the test condition of 230 DEG C and 2.16 kg is 15-70 g / 10 min. The bonding film layer comprises the following components: POE resin, wherein the melting temperature of the POE resin is 100-130 DEG C. The weight ratio of the PP resin to the POE resin is (80-95):(4-15). The high-temperature-resistant PP honeycomb tube has the advantages of low odor, low harmful substance content and recyclability, and also has excellent high-temperature mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of honeycomb sandwich panel technology, specifically relating to a high-temperature resistant PP honeycomb tube, its preparation method, and its application. Background Technology

[0002] Sandwich panels, characterized by their lightweight nature, are increasingly used in automotive spare tire covers. Early sandwich panels often featured a paper honeycomb core, whose key advantage was excellent high-temperature load-bearing capacity with no performance degradation at high temperatures. However, the production process of paper honeycomb sandwich panels requires the use of thermoplastic adhesives or thermosetting resins to bond the surface layer of the sandwich structure to the paper honeycomb core. This results in products with excessive odor and harmful substance content, failing to comply with relevant national regulations. Furthermore, the product has a low recycling rate.

[0003] To reduce the odor and harmful substance content of sandwich panels and improve their recyclability, thermoplastic polypropylene (PP) round tube honeycomb cores are increasingly being used to replace traditional paper honeycomb panels. However, the mechanical properties of PP honeycomb sandwich panels degrade significantly at high temperatures, with bending performance decreasing by more than 50% at 80°C. Therefore, to expand the application range of PP honeycomb sandwich panels, it is urgent to improve the high-temperature mechanical properties of PP honeycomb cores. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention aims to provide a high-temperature resistant PP honeycomb tube, its preparation method, and its application.

[0005] To achieve its purpose, the technical solution adopted by this invention is as follows:

[0006] A high-temperature resistant PP honeycomb tube is composed of several PP tubes fixedly bonded together. The inner diameter of the PP tube is 3-10 mm, and the wall thickness is 0.1-1 mm. The PP tube includes a tube body and an adhesive film layer disposed on the surface of the tube body. The tube body includes the following components: PP resin, wherein the melt index of the PP resin under the test conditions of 230℃ and 2.16 kg is 15-70 g / 10 min; the adhesive film layer includes the following components: POE resin, wherein the melt temperature of the POE resin is 100-130℃; the weight ratio of the PP resin to the POE resin is (80-95):(4-15).

[0007] The melt index of the PP resin was tested according to GB / T 3682.1-2018, and the melting temperature of the POE resin was tested according to ISO 11357-3:2011 Differential Scanning Calorimetry (DSC) for Plastics - Part 3.

[0008] This invention uses PP with the aforementioned melt flow index as the base material to prepare PP honeycomb tubes, ensuring both extrusion efficiency and good control over the diameter of the extruded PP honeycomb tubes. Simultaneously, by using POE with the aforementioned melting temperature as the bonding medium between the PP honeycomb tubes, this invention effectively improves the interfacial temperature resistance of the PP honeycomb tubes, allowing them to maintain high interfacial strength at high temperatures. The flexural performance retention rate at 80°C is significantly improved, and mechanical properties are well preserved. If the melting temperature of POE resin is too high, the baking and bonding temperature must also be increased accordingly. Generally, the baking and bonding temperature needs to be about 20°C higher than the melting temperature of POE resin to fully melt POE. PP softens at around 155°C, leading to deformation of the PP honeycomb tubes. If the melting temperature of POE resin is too low, the interface of the PP honeycomb tubes will be damaged first under high-temperature conditions, resulting in a severe degradation of the high-temperature performance of the PP honeycomb tubes.

[0009] Furthermore, if the inner diameter of the PP pipe is too small and the wall thickness is too large, the weight of the PP pipe will increase, failing to reflect the lightweight characteristics of PP pipe, and will also increase the cost of use and the difficulty of processing. If the inner diameter of the PP pipe is too large, the rigidity of the PP pipe will decrease. If the wall thickness of the PP pipe is too small, uneven wall thickness is likely to occur during the production process, resulting in greater dispersion in the performance of the final product.

[0010] Preferably, the melt flow index of the PP resin under test conditions of 230℃ and 2.16kg is 25-50g / 10min. Using PP with this melt flow index allows for better control over the diameter of the extruded PP pipe.

[0011] Preferably, the PP resin is a homopolymer PP resin. Compared to copolymer PP resin, the present invention uses homopolymer PP resin, which exhibits superior temperature resistance.

[0012] Preferably, the melting temperature of the POE resin is 110–120°C.

[0013] Preferably, the tube body comprises the following components in parts by weight: 80-95 parts of PP resin and 1-5 parts of other additives. The other additives include, but are not limited to, nucleating agents, antioxidants, and color masterbatches.

[0014] Preferably, the inner diameter of the PP pipe is 5-8 mm and the wall thickness is 0.3-0.5 mm.

[0015] The present invention also provides a method for preparing the high-temperature resistant PP honeycomb tube, which includes the following steps:

[0016] (1) PP pipes are prepared by co-extrusion process;

[0017] (2) The PP tubes prepared in step (1) are assembled in a fixed frame, and then heated at 130-150°C for 15-25 minutes to soften the adhesive film layer on the PP tubes and bond the adjacent PP tubes together. After cooling and shaping, the high-temperature resistant PP honeycomb tube is obtained.

[0018] Preferably, the co-extrusion process uses a single-screw extruder. The formulation components of the tube body and the formulation components of the adhesive film layer are respectively added into the corresponding barrels of the extruder. The screw diameter of the formulation components of the tube body is 60 mm, and the screw diameter of the formulation components of the adhesive film layer is 40 mm. The temperature of the extruder is controlled at 170-200℃.

[0019] The present invention also provides the application of the high-temperature resistant PP honeycomb tube in the preparation of sandwich panels.

[0020] The present invention also provides a sandwich panel comprising a honeycomb core made of the high-temperature resistant PP honeycomb tube, and surface layers disposed on the upper and lower surfaces of the honeycomb core.

[0021] The honeycomb core is obtained by cutting the high-temperature resistant PP honeycomb tube to the required thickness. The cutting is performed using a hot-cutting method, that is, by heating the high-temperature resistant PP honeycomb with electric heating wires, with the temperature controlled between 190 and 220°C. Therefore, the thickness of the honeycomb core is determined by the spacing between the heating wires.

[0022] The present invention also provides the application of the sandwich panel in the preparation of an automotive spare tire cover.

[0023] The present invention also provides a spare tire cover for automobiles, which is made of the sandwich panel.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: The high-temperature resistant PP honeycomb tube provided by the present invention not only has the advantages of low odor, low content of harmful substances and recyclability of thermoplastic honeycomb core, but also has excellent high-temperature mechanical properties. When used as the honeycomb core of sandwich panel, the bending performance retention rate of sandwich panel can still reach more than 53% at 80°C, which solves the technical problem that the mechanical properties of existing PP honeycomb sandwich panels are significantly reduced at high temperatures. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the sandwich panel of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The raw materials used in the examples and comparative examples are all commercially available and sourced from the following sources:

[0028] PP-1, homopolymer PP resin, model PP HP150G, melt index is 15g / 10min (230℃, 2.16kg), manufacturer is Saudi Petrochemical.

[0029] PP-2, homopolymer PP resin, model PP N-Z30S, melt index is 25g / 10min (230℃, 2.16kg), manufacturer is Sinopec Maoming Branch;

[0030] PP-3, homopolymer PP resin, model PP H9018, melt index is 50g / 10min (230℃, 2.16kg), manufacturer is China Petroleum Lanzhou Petrochemical Company;

[0031] PP-4, homopolymer PP resin, model PP H-MN60, melt index is 65g / 10min (230℃, 2.16kg), manufacturer is Sinopec Beihai Refining & Chemical Co., Ltd.;

[0032] PP-5, homopolymer PP resin, model PP HP500G, melt index 3g / 10min (230℃, 2.16kg), manufacturer LyondellBasell;

[0033] PP-6, homopolymer PP resin, model RP5007, melt index 75g / 10min (230℃, 2.16kg), manufacturer: Daelim, South Korea;

[0034] PP-7, a copolymer PP resin, model TAIRIPRO K9017, melt index of 17g / 10min, manufacturer Formosa Plastics Corporation;

[0035] POE-1, melting temperature 100℃, model Engage 8480, manufacturer Dow Chemical;

[0036] POE-2, melting temperature 110℃, model FL 39F, manufacturer Versalis SpA;

[0037] POE-3, melting temperature 120℃, model LLDPE LL6201, manufacturer ExxonMobil Chemical;

[0038] POE-4, melting temperature 130℃, model DMDA-8920, manufacturer Dow Chemical;

[0039] POE-5, melting temperature 73℃, model Engage 8003, manufacturer Dow Chemical;

[0040] POE-6, melting temperature 140℃, model FL7641, manufacturer The Polyolefin Company (Singapore) Pte Ltd;

[0041] The additives are antioxidants, which are commercially available, and the same type was used in the examples and comparative examples.

[0042] Examples 1-10

[0043] Examples 1-10 provide a high-temperature resistant PP honeycomb tube, which is composed of several PP tubes fixedly bonded together. The inner diameter of the PP tube is 8 mm, and the wall thickness is 0.5 mm. The PP tube consists of a tube body and an adhesive film layer disposed on the surface of the tube body. The tube body is made of PP resin and additives, and the weight parts of PP resin and additives are shown in Table 1. The adhesive film layer is made of POE resin, and the weight parts of POE are shown in Table 1. The component contents of the tube body and the adhesive film layer are all calculated in parts by weight.

[0044] The preparation methods of the high-temperature resistant PP honeycomb tubes in Examples 1-10 are as follows:

[0045] (1) PP pipes were prepared by co-extrusion using a single screw extruder. The formulation components of the pipe body and the formulation components of the adhesive film layer were added to the corresponding barrels of the extruder. The screw diameter of the formulation components of the pipe body was 60 mm, and the screw diameter of the formulation components of the adhesive film layer was 40 mm. The temperature of the extruder was controlled at 170-200℃. The extruded PP pipes were then pulled to a vacuum water bath for cooling and shaping. The vacuum pressure was 0.003±0.001MPa, the cooling water temperature range was 13±2℃, and the traction speed range was 150-300m / min.

[0046] (2) The PP tubes prepared in step (1) are assembled in a fixed frame and then pushed into an oven at 130-150°C for 15-25 minutes to soften the adhesive film layer on the PP tubes and bond the adjacent PP tubes together. After cooling and shaping, the high-temperature resistant PP honeycomb tube is obtained.

[0047] Table 1

[0048]

[0049] Note: "-" in the table indicates that the component is not added, and the same applies below.

[0050] Comparative Examples 1-7 provide a PP honeycomb tube with an inner diameter of 8 mm and a wall thickness of 0.5 mm. The weight parts of the PP tube are shown in Table 2. The preparation method is the same as that of Examples 1-10.

[0051] Table 2

[0052]

[0053] The PP honeycomb tubes prepared in Examples 1-10 and Comparative Examples 1-7 were respectively made into sandwich panels. The preparation method is as follows: the PP honeycomb tube was hot-cut into a honeycomb core of a certain thickness. Then, a layer material (the layer material is PP / GF composite material) was laid on the upper and lower surfaces of the honeycomb core. The layer material was heated and melted at 205°C and a pressure of 3 bar was applied to bond the layer material to the honeycomb core. Finally, the layer material was cooled and shaped to obtain the sandwich panel.

[0054] The prepared sandwich panels were tested for performance according to the GB-T 1456-2005 standard for testing the bending performance of sandwich structures.

[0055] The test results are shown in Table 3.

[0056] Flexural performance retention (%) = Flexural bearing capacity at 80℃ / Flexural bearing capacity at 23℃ × 100%

[0057] Table 3

[0058]

[0059]

[0060] Effect Analysis: Examples 1-4 and Comparative Examples 1-2 show that the melt index of the PP in the tube layer affects the high-temperature mechanical properties of the sandwich panel. When using PP with a melt index of 15-70 g / 10min (230℃, 2.16 kg), the tube diameter is more uniform and the diameter dispersion is smaller, which is more conducive to the PP tubes in the sandwich panel cooperating to withstand bending at high temperatures. Therefore, the high-temperature mechanical properties of the sandwich panel are better in this case. Examples 1, 5-7, and Comparative Examples 3-4 show that the melting temperature of the POE in the adhesive film layer affects the high-temperature mechanical properties of the sandwich panel. When using POE with a melting temperature of 100-130℃, the high-temperature mechanical properties of the sandwich panel are better. Examples 1 and 10 also show that the sandwich panel has better temperature resistance when using homopolymer PP resin compared to copolymer PP resin. In Comparative Example 3, the low melting temperature of the POE used caused damage to the interface of the PP honeycomb tubes under high-temperature conditions, resulting in a severe degradation of the high-temperature performance of the sandwich panel. In Comparative Example 4, the excessively high melting temperature of the POE required a baking and bonding temperature of over 160°C to fully melt it. At 130–150°C, it failed to melt completely, leading to poor bonding with the PP tubes and ultimately poor high-temperature mechanical properties of the sandwich panel. Increasing the baking and bonding temperature to over 160°C would cause deformation of the PP honeycomb tubes, also resulting in poor mechanical properties of the sandwich panel.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention 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 the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high temperature resistant PP honeycomb tube, characterized in that, Composed of several PP tubes fixedly bonded together, the PP tubes have an inner diameter of 3~10mm and a wall thickness of 0.1~1mm; the PP tubes include a tube body and an adhesive film layer disposed on the surface of the tube body. The tube body includes the following components: PP resin, the PP resin having a melt index of 15~65g / 10min under test conditions of 230℃ and 2.16kg; the adhesive film layer includes the following components: POE resin, the POE resin having a melting temperature of 100~130℃; the weight ratio of the PP resin to the POE resin is (80~95):(4~15).

2. The high temperature resistant PP honeycomb tube according to claim 1, wherein, The melt flow index of the PP resin under test conditions of 230℃ and 2.16kg is 25~50g / 10min.

3. The high-temperature resistant PP honeycomb tube as described in claim 1, characterized in that, The PP resin is a homopolymer PP resin.

4. The high-temperature resistant PP honeycomb tube as described in claim 1, characterized in that, The melting temperature of the POE resin is 110~120℃.

5. The high-temperature resistant PP honeycomb tube as described in any one of claims 1 to 4, characterized in that, The tube body comprises the following components in parts by weight: 80-95 parts of PP resin and 1-5 parts of other additives, wherein the other additives include at least one of nucleating agent, antioxidant, and color masterbatch.

6. The method for preparing high-temperature resistant PP honeycomb tube according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) PP pipes are prepared by co-extrusion process; (2) The PP tubes prepared in step (1) are assembled in a fixed frame, and then heated at 130~150℃ for 15~25min to soften the adhesive film layer on the PP tubes and bond the adjacent PP tubes together. After cooling and shaping, the high temperature resistant PP honeycomb tube is obtained.

7. The application of the high-temperature resistant PP honeycomb tube as described in any one of claims 1 to 5 in the preparation of sandwich panels.

8. A sandwich panel, characterized in that, It includes a honeycomb core made of high-temperature resistant PP honeycomb tube as described in any one of claims 1 to 5, and a surface layer disposed on the upper and lower surfaces of the honeycomb core.

9. The application of the sandwich panel as described in claim 8 in the preparation of an automobile spare tire cover.

10. A spare tire cover for automobiles, characterized in that, Made from the sandwich panel as described in claim 8.

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