Polyolefin composite material and preparation method thereof

Abstract

The invention discloses a polyolefin composite material and a preparation method thereof, and belongs to the technical field of composite screen cloth. The polyolefin composite material comprises PP (polypropylene) gridding cloth and TPO (thermoplastic polyolefin) films attached to two sides of the PP gridding cloth. The preparation method comprises the following steps: uniformly coating one side of the PP gridding cloth with a TPO film melt subjected to tape casting, and uniformly coating the other side of the PP gridding cloth with the TPO film melt subjected to tape casting after curing; or the two layers of TPO films formed through calendaring are arranged on the two sides of the PP gridding cloth, and hot-press fitting is carried out. According to the polyolefin composite material provided by the invention, stripping of the gridding cloth and the film is not needed before recovery, integrated recovery can be carried out, the recovery process is greatly simplified, the recovery cost is reduced, meanwhile, the recovery efficiency is improved, and the environmental protection performance and sustainability of the material are remarkably enhanced.

Description

Technical Field

[0001] The invention belongs to the technical field of composite mesh cloths, and particularly relates to a polyolefin composite material and a preparation method thereof. Background Art

[0002] A mesh fabric is a product that combines a film and a mesh (grid). The mesh is typically sandwiched between two layers of film. Depending on the material and requirements, there may or may not be an adhesive layer between the film and mesh. Mesh fabric offers high strength and good tear resistance, as well as excellent water resistance, wind resistance, and weather resistance. Through specialized processing, it can also be flame-retardant and fire-resistant. It is widely used in a variety of fields, including building sunshades, industrial protection, outdoor leisure, and logistics and transportation. Common mesh fabrics include PVC mesh, TPU mesh, EVA mesh, and TPE mesh. These are often named after the film material, while the mesh is typically polyester or nylon. For example, Chinese invention patent application number 201610965862.7 discloses a flame-retardant PVC mesh fabric and its preparation method. The flame-retardant PVC mesh fabric comprises polyester industrial fabric coated with a polyvinyl chloride paste coating, which is then laminated with a polyvinyl chloride film. Another example is the Chinese invention patent with application number 201810801813.9, which discloses a preparation process for an economical wear-resistant mesh cloth. The base cloth is made of polyester fiber mesh cloth. The base cloth is first preheated to a high temperature of 160-180°C, and the PVC film is directly bonded to the upper and lower surfaces of the base cloth by extrusion casting at a high temperature of 160-180°C; then, an adhesive is used in combination with extrusion casting at 140-155°C to make the TPU film more firmly bonded to the upper surface; the surface of the prepared mesh cloth has high wear resistance, which plays a protective role for the mesh cloth as a whole.

[0003] The mesh and film of these sandwich materials on the market have significant differences in material polarity. During the recycling process, the film and mesh need to be peeled off first, which significantly increases the difficulty and cost of recycling. It also limits the recycling efficiency of the sandwich materials and poses challenges to environmental protection and sustainable development. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a composite material with a sandwich structure that can be recycled in one piece.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a polyolefin composite material includes a PP mesh cloth and a TPO film attached to both sides of the PP mesh cloth; the pore size of the PP mesh cloth is 2~5mm.

[0006] Another technical solution adopted by the present invention is: a method for preparing a polyolefin composite material, comprising the following steps: uniformly coating a tape-cast TPO film melt on one side of a PP mesh cloth, and after solidification, uniformly coating the tape-cast TPO film melt on the other side of the PP mesh cloth; Alternatively, two layers of calendered TPO film are placed on both sides of the PP mesh cloth and hot-pressed.

[0007] The beneficial effects of the present invention are as follows: the polyolefin composite material provided by the present invention is composited with a sparse PP mesh cloth and a TPO film. After use, only the additional parts of the non-composite material need to be removed, and there is no need to separate the mesh cloth from the film. The material can be recycled as a whole, which greatly simplifies the recycling process, reduces recycling costs, and improves recycling efficiency, significantly enhancing the environmental performance and sustainability of the material. It not only opens up a new path for the recycling and utilization of polyolefin composite materials, but also provides strong support for the green development of related industries. The polyolefin composite material provided by the present invention can be used in the preparation of waterproof bags and used as a waterproof bag material to replace traditional PVC materials, which is more environmentally friendly and lightweight. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is the effect picture of the composite material obtained by laminating the conventional PP mesh cloth with the film; Figure 2 This is a rendering of a polyolefin composite material after PP hexagonal mesh cloth is laminated to a film in accordance with a specific embodiment of the present invention; Figure 3 for Figure 1 The effect diagram of the waterproof bag prepared by the composite material; Figure 4 for Figure 2 The effect picture of the waterproof bag made of polyolefin composite material. DETAILED DESCRIPTION

[0009] To illustrate the technical content, achieved objectives and effects of the present invention in detail, the following description is given in conjunction with the embodiments and accompanying drawings.

[0010] A polyolefin composite material comprises a PP mesh and a TPO film laminated on both sides of the PP mesh. The PP mesh has a pore size of 2-5 mm. PP mesh has a large pore size and is relatively sparse. PP mesh is preferred due to its light weight. Mesh is a type of mesh.

[0011] In one or more embodiments, the PP mesh fabric is a PP hexagonal mesh fabric.

[0012] In one or more embodiments, the thickness of the TPO film is 0.15-0.35 mm.

[0013] From the above description, it can be seen that the beneficial effects of the present invention are: the polyolefin composite material provided by the present invention is composed of a sparse PP mesh cloth and a TPO film, which does not need to be separated during recycling and can be directly broken up for re-melting and recycling, which greatly reduces the difficulty of recycling, improves the recycling efficiency, and is conducive to the recycling and reuse of waste materials.

[0014] In one or more embodiments, the TPO film comprises, by weight, 5-20% TPO, 50-70% POE, 5-20% PP, and 3-10% LLDPE. Furthermore, the film may comprise one or more of 0.5-3% polyethylene wax, 0.1-0.3% UV absorber, and 0.1-0.3% antioxidant.

[0015] In one or more embodiments, the TPO film comprises, by weight, 30-55% TPO, 30-55% POE, 3-10% PP, and 1-5% LLDPE. Furthermore, the film may comprise one or more of 0-1% polyethylene wax, 0.1-0.3% UV absorber, and 0.1-0.3% antioxidant. Polyethylene wax may not be added when using a casting process, but is preferably present in an amount of 0.5-1% when using a calendering process.

[0016] The commercially available film formulas generally contain high levels of low-priced PP and LDPE, and certain fillers, resulting in poor toughness and weather resistance and easy aging. The present invention adjusts the formula and adds more TPO and POE components to make the ratio reasonable, thereby increasing the flexibility, low-temperature resistance and weather resistance of the TPO film; and can form a firm sandwich structure with the PP mesh.

[0017] The preparation method of the polyolefin composite material comprises the following steps: The cast TPO film melt is evenly coated on one side of the PP mesh cloth. After solidification, the cast TPO film melt is evenly coated on the other side of the PP mesh cloth. Alternatively, two layers of calendered TPO film are placed on both sides of the PP mesh cloth and hot-pressed.

[0018] In one or more embodiments, the PP mesh is preheated at a temperature of 40-70° C. The preheating temperature range of the PP mesh is 0-70° C., preferably 50-70° C. This can prevent mesh deformation while ensuring good adhesion.

[0019] In one or more embodiments, the temperature of the hot pressing bonding is 150-170° C., and the pressure is 30-50 kgf.

[0020] In one or more embodiments, the tension control parameter of the PP mesh cloth during the transmission process before being bonded to the film is 3-5N.

[0021] In one or more embodiments, the PP mesh is transported using a weighing tension controller before being laminated to the film.

[0022] As can be seen from the above description, due to the problem that PP yarn itself is light and has poor strength, it is easy to have the problem of yarn breakage during the manufacturing process, making it rare to use pure PP yarn for mesh weaving in the field. Even if pure PP yarn can be used to weave mesh, the resulting mesh has a large elongation, which makes it very easy to deform during the processing. If the traditional mesh manufacturing process is used, the mesh will be completely deformed and unusable. When the mesh is greatly deformed, the subsequent coating process cannot be achieved. Therefore, it is extremely difficult to use PP mesh for processing. Generally, PET mesh is used for coating processing on the market to prepare waterproof composite materials. The present application can overcome the above problems by strictly controlling the tension during transmission and cooperating with a weighing tension controller for transmission, ensuring the normal progress of production and the yield rate of the product.

[0023] The first embodiment of the present invention is: Polyolefin composite material, including PP mesh cloth and TPO film laminated on both sides of the PP mesh cloth; the pore size of the PP mesh cloth is 2mm; the thickness of the TPO film is 0.15mm; The polyolefin composite material is prepared by sending two rolls of calendered TPO film and one roll of PP mesh cloth to a laminating machine simultaneously in the order of placing the PP mesh cloth in the middle and the TPO film on both sides, and performing hot pressing lamination in the laminating machine at a temperature of 150° C. and a pressure of 50 kgf. TPO film is made of the following raw materials: 55% TPO, 37.5% POE, 5% PP, 1% polyethylene wax, 1% LLDPE, 0.3% UV absorber UV-531 and 0.2% antioxidant 1076.

[0024] The second embodiment of the present invention is: The difference between Example 2 and Example 1 lies in the different raw material compositions. In Example 2, the TPO film is made of the following raw materials: 17% TPO, 50% POE, 20% PP, 10% LLDPE and 3% polyethylene wax.

[0025] The third embodiment of the present invention is a polyolefin composite material comprising a PP mesh cloth with a pore size of 5 mm and a TPO film attached to both sides of the PP mesh cloth; the thickness of the TPO film is 0.2 mm; The preparation method of the above-mentioned polyolefin composite material is: S1. Weigh, by weight percentage, 14% TPO, 68.5% POE, 10% PP, 7% LLDPE, 0.2% UV absorber UV-531, and 0.3% antioxidant 1076; S2. The TPO film melt formed by tape casting using the S1 raw material is evenly coated on one side of a PP mesh cloth with a pore size of 5 mm. After solidification, the TPO film is cast on the other side of the PP mesh cloth using the same method.

[0026] The fourth embodiment of the present invention is: The difference between Example 4 and Example 3 is that the raw material ratio in S1 is different. In Example 4, 20% TPO, 70% POE, 6.8% PP, 3% LLDPE, 0.1% ultraviolet absorber UV-531 and 0.1% antioxidant 1076 are weighed in percentage by weight.

[0027] The fifth embodiment of the present invention is: Polyolefin composite material, including PP mesh cloth with a pore size of 3mm and TPO film laminated on both sides of the PP mesh cloth; the thickness of the TPO film is 0.35mm; The preparation method of the above-mentioned polyolefin composite material is: S1. Weigh 5% TPO, 67.5% POE, 18% PP, 9% LLDPE and 0.5% polyethylene sodium by weight; then calender the above raw materials to form a TPO film; S2. Send two rolls of TPO film obtained in S1 and one roll of PP mesh cloth with a pore size of 3 mm to a laminating machine simultaneously in the order of PP mesh cloth in the middle and TPO film on both sides, and perform hot pressing lamination in the laminating machine at a temperature of 170°C and a pressure of 30 kgf.

[0028] The sixth embodiment of the present invention is: Polyolefin composite material, including PP mesh cloth with a pore size of 4mm and TPO film laminated on both sides of the PP mesh cloth; the thickness of the TPO film is 0.3mm; The preparation method of the above-mentioned polyolefin composite material is: S1. Weigh 10% TPO, 66% POE, 15% PP, 8% PE and 1% polyethylene sodium by weight; then calender the above raw materials to form a TPO film; S2. Send two rolls of TPO film obtained in S1 and one roll of PP mesh cloth with a pore size of 4 mm to a laminating machine simultaneously in the order of PP mesh cloth in the middle and TPO film on both sides, and perform hot pressing lamination in the laminating machine at a temperature of 160°C and a pressure of 40 kgf.

[0029] The seventh embodiment of the present invention is: The difference between Example 7 and Example 5 is that the raw material ratio in S1 is different. In Example 7, 20% TPO, 67% POE, 5% PP, 4.5% LLDPE and 3% polyethylene sodium raw material, 0.25% ultraviolet absorber UV-531 and 0.25% antioxidant 1076 are weighed by weight percentage.

[0030] The eighth embodiment of the present invention is: The difference between Example 8 and Example 3 is that the raw material ratio in S1 is different. In Example 8, 30% TPO, 55% POE, 10% PP and 5% LLDPE are weighed in percentage by weight.

[0031] The eighth embodiment of the present invention is: The difference between Example 8 and Example 5 is that the raw material ratio in S1 is different. In Example 9, 55% TPO, 35% POE, 6% PP, 3% LLDPE, 0.6% polyethylene sodium, 0.2% ultraviolet absorber UV-531 and 0.2% antioxidant 1076 are weighed in percentage by weight.

[0032] The eighth embodiment of the present invention is: The difference between Example 8 and Example 5 is that the raw material ratio in S1 is different. In Example 9, 55% TPO, 30% POE, 9% PP, 5% LLDPE, 0.4% polyethylene sodium, 0.3% ultraviolet absorber UV-531 and 0.3% antioxidant 1076 are weighed in percentage by weight.

[0033] The effect diagram of the waterproof bag prepared by the polyolefin composite material prepared by the present invention is shown in FIG. Figure 4 As shown, Figure 4 The mosaic part in the middle is the product logo. It can be seen that the resulting product grid is regular and there is no deformation problem.

[0034] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's description and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A polyolefin composite material, characterized in that: It comprises a PP mesh cloth and a TPO film attached to both sides of the PP mesh cloth; the pore size of the PP mesh cloth is 2-5 mm.

2. The polyolefin composite material according to claim 1, characterized in that The pore size of the PP mesh cloth is 2-5 mm.

3. The polyolefin composite material according to claim 1, characterized in that The thickness of the TPO film is 0.15-0.35 mm.

4. The polyolefin composite material according to claim 1, characterized in that The TPO film comprises, by weight percentage, 5-20% of TPO, 50-70% of POE, 5-20% of PP, and 3-10% of LLDPE.

5. The polyolefin composite material according to claim 1, characterized in that The TPO film further comprises, by weight percentage, one or more of 0.5-3% polyethylene wax, 0.1-0.3% ultraviolet absorber, and 0.1-0.3% antioxidant.

6. The method for preparing the polyolefin composite material according to claim 1, comprising the steps of: The cast TPO film melt is evenly coated on one side of the PP mesh cloth. After solidification, the cast TPO film melt is evenly coated on the other side of the PP mesh cloth. Alternatively, two layers of calendered TPO film are placed on both sides of the PP mesh cloth and hot-pressed.

7. The preparation method according to claim 6, wherein the PP mesh cloth is a PP mesh cloth that has been preheated, and the preheating temperature is 40-70°C. The preparation method according to claim 6 , wherein the temperature of the hot pressing bonding is 150-170° C. and the pressure is 30-50 kgf.

9. The preparation method according to claim 6, wherein the tension control parameter of the PP mesh cloth during the transmission process before being bonded to the film is 3-5N.

10. The preparation method according to claim 6, wherein the PP mesh cloth is transported using a weighing tension controller before being laminated to the film.

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