High-temperature-resistant bidirectional-stretching polypropylene plastic bottle and preparation method thereof

Abstract

This invention relates to the field of plastic container technology, and proposes a high-temperature resistant biaxially oriented polypropylene (BOPP) plastic bottle and its preparation method. The high-temperature resistant BOPP plastic bottle comprises the following components in parts by weight: 90-100 parts polypropylene, 12-16 parts silica-modified lignin fiber, 16-20 parts block copolymer, and 0.2-0.8 parts antioxidant; the block copolymer is a PCL-PEG-PCL block copolymer. This technical solution solves the problem of poor high-temperature resistance and mechanical properties of existing polypropylene plastic bottles.

Description

Technical Field

[0001] This invention relates to the field of plastic container technology, specifically to a high-temperature resistant biaxially oriented polypropylene plastic bottle and its preparation method. Background Technology

[0002] Plastic bottles are primarily made from materials such as polyethylene or polypropylene with the addition of various additives. Plastic bottles widely use polyester (PET), polyethylene (PE), and polypropylene (PP) as raw materials, with the addition of appropriate additives. After being heated at high temperatures, they are formed into plastic containers through blow molding, extrusion blow molding, and injection molding using plastic molds. Polypropylene is a semi-crystalline thermoplastic with high impact resistance, strong mechanical properties, and resistance to various organic solvents and acid / alkali corrosion. It has wide applications in industry and is one of the most common polymer materials.

[0003] Ordinary PP materials cannot meet the requirements of plastic bottles under high-temperature conditions due to insufficient high-temperature resistance. In addition, their insufficient mechanical properties limit the application and promotion of PP materials in high-temperature resistant plastic bottles. Therefore, improving the high-temperature resistance and mechanical properties of PP materials and their application in plastic bottles has become a key issue that urgently needs to be addressed. Summary of the Invention

[0004] This invention proposes a high-temperature resistant biaxially oriented polypropylene plastic bottle and its preparation method, which solves the problem of poor high-temperature resistance and mechanical properties of polypropylene plastic bottles in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] This invention proposes a high-temperature resistant biaxially oriented polypropylene plastic bottle, comprising the following components in parts by weight: 90-100 parts of polypropylene, 12-16 parts of silica-modified lignin fiber, 16-20 parts of block copolymer, and 0.2-0.8 parts of antioxidant; wherein the block copolymer is a PCL-PEG-PCL block copolymer.

[0007] As a further technical solution, the block copolymer is composed of a first block copolymer and a second block copolymer with a mass ratio of 2:6~8.

[0008] As a further technical solution, the molecular weight of the first block copolymer is 1000~2000; the molecular weight of the second block copolymer is 6000~8000.

[0009] By using block copolymers of different molecular weights and adjusting their mass ratio, the high-temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles were further improved.

[0010] As a further technical solution, the mass ratio of silica to lignin fiber in the silica-modified lignin fiber is 1~3:5.

[0011] By adjusting the mass ratio of silica to lignin fiber in silica-modified lignin fiber, the coverage of silica on the surface of lignin fiber was adjusted, further improving the high-temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles.

[0012] As a further technical solution, the method for preparing silica-modified lignin fiber includes the following steps: dispersing lignin fiber in a silane coupling agent, drying it, and mixing it with silica to obtain silica-modified lignin fiber.

[0013] As a further technical solution, the silane coupling agent is one or more of KH550, KH540, and KH560.

[0014] As a further technical solution, the antioxidant includes two or more of antioxidant 1010, antioxidant 686, and antioxidant 246.

[0015] This invention also proposes a method for preparing the high-temperature resistant biaxially oriented polypropylene plastic bottle, comprising the following steps:

[0016] S1. Mix the polypropylene and the remaining components to obtain a preliminary mixture;

[0017] S2. The initial mixture is melt-injected and blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

[0018] This invention also proposes a method for preparing the high-temperature resistant biaxially oriented polypropylene plastic bottle, comprising the following steps:

[0019] A1. The block copolymer and silica-modified lignin fiber are mixed and granulated to obtain the initial mixture particles;

[0020] A2. Mix the polypropylene, the premixed particles, and the remaining components to obtain the premix;

[0021] A3. The initial mixture is melt-injected and blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

[0022] By mixing and granulating block copolymers and silica-modified lignin fibers, the block copolymers are coated on the surface of the silica-modified lignin fibers, which improves the compatibility between the silica-modified lignin fibers and the polypropylene matrix, and further improves the high temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles.

[0023] As a further technical solution, in step A1, the particle size of the initial mixture is 100~200 mesh.

[0024] The working principle and beneficial effects of this invention are as follows:

[0025] 1. In this invention, silica-modified lignin fibers are introduced into polypropylene. The silica-modified lignin fibers form a mechanical bond with the interior of the polypropylene, which improves the crystallinity of the polypropylene. In addition, PCL-PEG-PCL block copolymer is used to make good compatibility between the non-polar segments in the block copolymer and the polypropylene, which significantly improves the high temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] In the following examples and comparative examples, the polypropylene grade was S1003; the silica particle size was 2000 mesh; the average length of the lignin fiber was 200 μm; and the PCL-PEG-PCL block copolymers with molecular weights of 1000, 2000, 6000, and 8000 were purchased from Beijing Jingpi Technology Co., Ltd., with catalog numbers JP0105-1k, JP0105-2k, JP0105-6k, and JP0105-8k, respectively.

[0028] Example 1

[0029] High-temperature resistant biaxially oriented polypropylene plastic bottle, comprising the following components in parts by weight: 90 parts polypropylene, 12 parts silica-modified lignin fiber, 16 parts PCL-PEG-PCL block copolymer with a molecular weight of 8000, and 0.2 parts antioxidant 1010.

[0030] The preparation method of silica-modified lignin fiber includes the following steps: dispersing lignin fiber in silane coupling agent KH550, drying, and mixing with silica to obtain silica-modified lignin fiber; wherein the mass ratio of silica to lignin fiber is 0.5:5.

[0031] A method for preparing high-temperature resistant biaxially oriented polypropylene plastic bottles includes the following steps:

[0032] S1. Mix the polypropylene and the remaining components to obtain a preliminary mixture;

[0033] S2. The initial mixture is melted and injected into the plastic, and then blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

[0034] Example 2

[0035] High-temperature resistant biaxially oriented polypropylene plastic bottle, comprising the following components in parts by weight: 95 parts polypropylene, 13 parts silica-modified lignin fiber, 18 parts PCL-PEG-PCL block copolymer with a molecular weight of 8000, 0.2 parts antioxidant 1010, and 0.3 parts antioxidant 686;

[0036] The preparation method of silica-modified lignin fiber includes the following steps: dispersing lignin fiber in silane coupling agent KH540, drying, and mixing with silica to obtain silica-modified lignin fiber; wherein the mass ratio of silica to lignin fiber is 0.5:5.

[0037] A method for preparing high-temperature resistant biaxially oriented polypropylene plastic bottles includes the following steps:

[0038] S1. Mix the polypropylene and the remaining components to obtain a preliminary mixture;

[0039] S2. The initial mixture is melted and injected into the plastic, and then blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

[0040] Example 3

[0041] High-temperature resistant biaxially oriented polypropylene plastic bottle, comprising the following components in parts by weight: 100 parts polypropylene, 16 parts silica-modified lignin fiber, 20 parts PCL-PEG-PCL block copolymer with a molecular weight of 8000, and 0.8 parts antioxidant 1010.

[0042] The preparation method of silica-modified lignin fiber includes the following steps: dispersing lignin fiber in silane coupling agent KH560, drying, and mixing with silica to obtain silica-modified lignin fiber; wherein the mass ratio of silica to lignin fiber is 0.5:5.

[0043] A method for preparing high-temperature resistant biaxially oriented polypropylene plastic bottles includes the following steps:

[0044] S1. Mix the polypropylene and the remaining components to obtain a preliminary mixture;

[0045] S2. The initial mixture is melted and injected into the plastic, and then blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

[0046] Example 4

[0047] The only difference between this embodiment and Embodiment 3 is that the mass ratio of silica to lignin fiber is 4:5.

[0048] Example 5

[0049] The only difference between this embodiment and Embodiment 3 is that the mass ratio of silica to lignin fiber is 1:5.

[0050] Example 6

[0051] The only difference between this embodiment and Embodiment 3 is that the mass ratio of silica to lignin fiber is 3:5.

[0052] Example 7

[0053] The only difference between this embodiment and Example 6 is that the molecular weight of the PCL-PEG-PCL block copolymer is 1000.

[0054] Example 8

[0055] The only difference between this embodiment and Example 6 is the addition of 5 parts of PCL-PEG-PCL block copolymer with a molecular weight of 1000 and 15 parts of PCL-PEG-PCL block copolymer with a molecular weight of 8000.

[0056] Example 9

[0057] The only difference between this embodiment and Example 6 is the addition of 4 parts of PCL-PEG-PCL block copolymer with a molecular weight of 1000 and 16 parts of PCL-PEG-PCL block copolymer with a molecular weight of 8000.

[0058] Example 10

[0059] The only difference between this embodiment and Example 6 is that the PCL-PEG-PCL block copolymer with a molecular weight of 8000 is not added, but 4 parts of PCL-PEG-PCL block copolymer with a molecular weight of 2000 and 16 parts of PCL-PEG-PCL block copolymer with a molecular weight of 6000 are added.

[0060] Example 11

[0061] The difference between this embodiment and Embodiment 10 lies only in the preparation method of the high-temperature resistant biaxially oriented polypropylene plastic bottle, which includes the following steps:

[0062] A1. The block copolymer and silica-modified lignin fiber are mixed and granulated to obtain a preliminary mixture with a particle size of 100 mesh.

[0063] A2. Mix the polypropylene, the premixed particles, and the remaining components to obtain the premix;

[0064] A3. The initial mixture is melted and injected into the plastic, and then blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

[0065] Example 12

[0066] The difference between this embodiment and Embodiment 10 lies only in the preparation method of the high-temperature resistant biaxially oriented polypropylene plastic bottle, which includes the following steps:

[0067] A1. The block copolymer and silica-modified lignin fiber are mixed and granulated to obtain a preliminary mixture with a particle size of 200 mesh.

[0068] A2. Mix the polypropylene, the premixed particles, and the remaining components to obtain the premix;

[0069] A3. The initial mixture is melted and injected into the plastic, and then blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

[0070] Comparative Example 1

[0071] The only difference between this comparative example and Example 3 is that the PCL-PEG-PCL intercalation copolymer is not added.

[0072] Comparative Example 2

[0073] The only difference between this comparative example and Example 3 is that silica-modified lignin fibers are not added.

[0074] Comparative Example 3

[0075] The only difference between this comparative example and Example 3 is that silica-modified lignin fiber is not added, while 1.5 parts of silica and 14.5 parts of lignin fiber are added.

[0076] The load deformation temperature (applied bending stress 0.45 MPa) of the high-temperature resistant biaxially oriented polypropylene plastic bottles prepared in Examples 1-12 and Comparative Examples 1-3 were tested according to standard GB / T 1634.1-2019 "Determination of load deformation temperature of plastics - Part 1 General test method".

[0077] The tensile strength of the high-temperature resistant biaxially oriented polypropylene plastic bottles prepared in Examples 1-12 and Comparative Examples 1-3 were tested according to the standard GB / T 1040.1-2018 "Determination of tensile properties of plastics - Part 1: General".

[0078] The test results are shown in the table below:

[0079]

[0080] By comparing the data of Examples 1-12 and Comparative Examples 1-3, it was found that the biaxially oriented polypropylene plastic bottles prepared in Examples 1-12 had higher load deformation temperature and tensile strength compared with Comparative Examples 1-3. This indicates that introducing silica-modified lignin fibers into polypropylene and combining them with PCL-PEG-PCL block copolymers can significantly improve the high temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles.

[0081] Comparing the data from Examples 6-10, it was found that the biaxially oriented polypropylene plastic bottles prepared in Examples 8-10 had higher load deformation temperature and tensile strength compared to Examples 6-7. This indicates that by compounding block copolymers of different molecular weights and adjusting their mass ratio, the high temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles can be further improved.

[0082] By comparing the data from Examples 3-6, it was found that the biaxially oriented polypropylene plastic bottles prepared in Examples 5-6 had higher load deformation temperature and tensile strength compared with Examples 3-4. This indicates that by adjusting the mass ratio of silica to lignin fiber in silica-modified lignin fiber, the high temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles can be further improved.

[0083] Comparing the data from Examples 10-12, it was found that the biaxially oriented polypropylene plastic bottles prepared in Examples 11-12 had higher load deformation temperature and tensile strength compared with Example 10. This indicates that by mixing block copolymers and silica-modified lignin fibers for granulation, the high temperature resistance and mechanical properties of biaxially oriented polypropylene plastic bottles can be further improved.

[0084] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-temperature resistant biaxially oriented polypropylene plastic bottle, characterized in that, The product comprises the following components in parts by weight: 90-100 parts polypropylene, 12-16 parts silica-modified lignin fiber, 16-20 parts block copolymer, and 0.2-0.8 parts antioxidant; wherein the block copolymer is a PCL-PEG-PCL block copolymer. The block copolymer is composed of a first block copolymer and a second block copolymer in a mass ratio of 1:3 to 4, wherein the molecular weight of the first block copolymer is smaller than that of the second block copolymer. The molecular weight of the first block copolymer is 1000~2000; the molecular weight of the second block copolymer is 6000~8000. In the silica-modified lignin fiber, the mass ratio of silica to lignin fiber is 1~3:5; The method for preparing silica-modified lignin fiber includes the following steps: dispersing lignin fiber in a silane coupling agent, drying it, and mixing it with silica to obtain silica-modified lignin fiber.

2. The high-temperature resistant biaxially oriented polypropylene plastic bottle according to claim 1, characterized in that, The silane coupling agent is one or more of KH550, KH540, and KH560.

3. The high-temperature resistant biaxially oriented polypropylene plastic bottle according to claim 1, characterized in that, The antioxidants include one or more of antioxidants 1010, antioxidant 686, and antioxidant 246.

4. A method for preparing a high-temperature resistant biaxially oriented polypropylene plastic bottle according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Mix the polypropylene and the remaining components to obtain a preliminary mixture; S2. The initial mixture is melt-injected and blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

5. A method for preparing a high-temperature resistant biaxially oriented polypropylene plastic bottle according to any one of claims 1 to 3, characterized in that, Includes the following steps: A1. The block copolymer and silica-modified lignin fiber are mixed and granulated to obtain the initial mixture particles; A2. Mix the polypropylene, the premixed particles, and the remaining components to obtain the premix; A3. The initial mixture is melt-injected and blow-molded to obtain a high-temperature resistant biaxially oriented polypropylene plastic bottle.

6. The method for preparing a high-temperature resistant biaxially oriented polypropylene plastic bottle according to claim 5, characterized in that, In step A1, the particle size of the initial mixture is 100-200 mesh.

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