Composite pp-r pipe material and preparation method and application thereof

Abstract

The application discloses a kind of composite PP-R pipe materials and preparation method and application thereof, it is related to PP-R pipe material technical field, the composite PP-R pipe material, including by inside to outside sequentially connected PP-R inner layer, impact resistance oxygen barrier layer and PP-R outer layer, the impact resistance oxygen barrier layer includes parylene, polyglycolic acid, compatibilizer.The composite PP-R pipe material adds impact resistance oxygen barrier layer as middle layer in it, the material of the impact resistance oxygen barrier layer uses the cooperation of parylene and polyglycolic acid (PGA), with excellent mechanical properties and gas barrier property, and can keep structural performance stable under low temperature environment below-10 DEG C, can be applied in PP-R pipe material system to improve its low temperature brittleness, improve low temperature impact resistance.

Description

Technical Field

[0001] This invention relates to the field of PP-R pipe technology, and more specifically, to a composite PP-R pipe material, its preparation method, and its application. Background Technology

[0002] The PP-R pipe industry is experiencing rapid growth. However, due to the extremely low oxygen barrier properties of ordinary PP-R pipes, microorganisms easily proliferate after prolonged use, affecting water quality and hygiene. Therefore, the requirements for the oxygen barrier properties of PP-R pipes are gradually increasing. Furthermore, the toughness of PP-R pipes decreases sharply when the ambient temperature drops. When the ambient temperature is below 0℃, PP-R exhibits typical brittle fracture, making it prone to pipe bursting in cold climates. It is also more susceptible to damage during transportation and storage, significantly limiting the application scenarios and geographical scope of PP-R pipes. Therefore, improving the low-temperature toughness of PP-R and preparing low-temperature impact-resistant (high-impact) PP-R materials are crucial technical challenges that must be addressed in developing high-performance PP-R pipes.

[0003] Existing low-temperature toughening techniques for PP-R pipes primarily involve adding β-nucleating agents to the pipe material. Introducing these nucleating agents increases the crystallinity of the PP-R pipe, inducing the formation of more β-crystals. This simultaneously refines crystal size, accelerates the crystallization rate, and increases the crystallization temperature, reducing internal stress caused by different cooling rates between the inner and outer layers of the PP-R pipe. This improves the impact resistance of the PP-R pipe and significantly enhances its low-temperature toughness, reducing damage or breakage in northern regions. However, the use of β-nucleating agents to improve PP-R pipes often only improves the impact resistance at around 0°C, with little effect on impact resistance at lower temperatures. Furthermore, it fails to improve the oxygen barrier properties of the PP-R pipe. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects and shortcomings of existing PP-R pipes and provide a composite PP-R pipe material that can improve the low-temperature impact resistance of PP-R pipes while also taking into account oxygen barrier properties.

[0005] Another objective of this invention is to provide a method for preparing composite PP-R pipe material.

[0006] Another objective of this invention is to provide an application of composite PP-R pipe material in the preparation of low-temperature impact-resistant pipes.

[0007] The above-mentioned objective of this invention is achieved through the following technical solution:

[0008] This invention protects a composite PP-R pipe material, comprising a PP-R inner layer, an impact-resistant oxygen barrier layer, and a PP-R outer layer connected sequentially from the inside out.

[0009] The impact-resistant oxygen barrier layer comprises the following components in parts by weight: 120 parts of parylene, 20-60 parts of polyglycolic acid, and 12-30 parts of compatibilizer.

[0010] The composite PP-R pipe material of this invention adopts a sandwich structure consisting of a PP-R inner layer, an impact-resistant oxygen barrier layer, and a PP-R outer layer, with the impact-resistant oxygen barrier layer as the middle layer. The impact-resistant oxygen barrier layer is made of a combination of parylene and polyglycolic acid (PGA), which has excellent mechanical properties and gas barrier properties, and can maintain structural stability in low-temperature environments below -10°C. It can be used in PP-R pipe systems to improve their low-temperature brittleness and enhance their low-temperature impact resistance. At the same time, a compatibilizer is introduced to improve the interfacial adhesion between the impact-resistant oxygen barrier layer and the PP-R material, thereby improving compatibility and facilitating the stable existence of the impact-resistant oxygen barrier layer in the PP-R pipe system.

[0011] Polyglycolic acid (PGA) possesses excellent gas barrier properties and low-temperature ductility, maintaining structural stability at low temperatures, but it is prone to decomposition at high temperatures and in humid environments. Parylene exhibits excellent heat resistance, weather resistance, and chemical stability. Furthermore, its unique polydimethylbenzene structure can encapsulate PGA, easily forming micron-sized films in the molten state. By optimizing the ratio of PGA to PDM, a film material with high gas barrier properties, strong low-temperature impact resistance, and excellent mechanical properties can be obtained.

[0012] In some embodiments, the parylene comprises at least 60 wt% of the impact-resistant oxygen barrier layer.

[0013] In some embodiments, the compatibilizer is polypropylene grafted with maleic anhydride. This compatibilizer helps improve the thermal adhesion performance between the impact-resistant oxygen barrier layer and PP-R.

[0014] In some embodiments, the impact-resistant oxygen barrier layer comprises the following components in parts by weight: 120 parts of parylene, 20-40 parts of polyglycolic acid, and 14-24 parts of compatibilizer.

[0015] In some embodiments, the thickness ratio of the PP-R inner layer, the impact-resistant oxygen barrier layer and the PP-R outer layer is (24-29):(8-14):(55-65); preferably (25-28):(9-13):(56-62).

[0016] In some embodiments, the melt flow rate of the PP-R inner and outer layer materials at 230°C and 2.16 kg is 0.1-0.5 g / 10 min, preferably 0.2-0.3 g / 10 min.

[0017] In some embodiments, the intrinsic viscosity of the poly(p-xylene) is 0.3-1.5 dl / g, preferably 0.6-1.2 dl / g.

[0018] In some embodiments, the intrinsic viscosity of the polyglycolic acid is 0.5-2.2 dl / g, preferably 1.0-1.7 dl / g.

[0019] This invention protects a method for preparing a composite PP-R pipe material, comprising the following steps:

[0020] (1) After mixing parylene and compatibilizer evenly, add polyglycolic acid for melt blending and extrusion to obtain impact-resistant oxygen barrier layer material;

[0021] (2) The raw materials of the PP-R inner layer, the impact-resistant oxygen barrier layer and the PP-R outer layer are co-extruded and shaped to obtain composite PP-R pipe material.

[0022] In some embodiments, in step (1), the extrusion process is as follows: conveying section temperature 90-180℃, melting section temperature 140-230℃, homogenization section temperature 160-230℃, die temperature 160-230℃, and screw speed 100-150rpm.

[0023] Preferably, the temperature of the melting section is 150–230°C.

[0024] Preferably, in step (2), the three-layer co-extrusion shaping extrusion process is as follows: conveying section temperature 90~180℃, melting section temperature 160~230℃, homogenization section temperature 160~230℃, die temperature 180~230℃, and screw speed 90~120rpm.

[0025] This invention protects the application of a composite PP-R pipe material in the manufacture of low-temperature impact-resistant pipes. It can be used in cold climates below 0°C, is less prone to pipe bursting, and offers high safety during transportation and storage, thus expanding the application scenarios and geographical scope of PP-R pipes.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] This invention provides a composite PP-R pipe material in which an impact-resistant oxygen barrier layer is used as the intermediate layer. The impact-resistant oxygen barrier layer is made of a compound of parylene and polyglycolic acid, which has excellent mechanical properties and gas barrier properties, and can maintain structural performance stability in low-temperature environments below -10℃. It can be used in PP-R pipe systems to improve their low-temperature brittleness and enhance their low-temperature impact resistance. Detailed Implementation

[0028] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0029] The raw materials used in the following examples and comparative examples are as follows:

[0030] Random copolymer polypropylene (PP-R) 1#: melt flow rate of 0.26 g / 10 min at 230℃ and 2.16 kg; PA14D, Xuzhou Haitian Petrochemical Co., Ltd.

[0031] Random copolymer polypropylene (PP-R) 2#: melt flow rate of 0.22 g / 10 min at 230℃ and 2.16 kg; 4220, Beijing Yanshan Branch of China Petroleum & Chemical Corporation.

[0032] Poly(p-xylene) 1#: intrinsic viscosity is 1.0 dl / g; Shenzhen Fangcunda Technology Co., Ltd.

[0033] Poly(p-xylene) 2#: intrinsic viscosity is 0.8 dl / g; Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0034] Polyglycolic acid (PGA) 1#: intrinsic viscosity is 1.5 dl / g; Wuhan Smike Biotechnology Co., Ltd.

[0035] Polyglycolic acid (PGA) 2#: intrinsic viscosity is 1.2 dl / g; Wuhan Ouke New Material Technology Co., Ltd.

[0036] Polypropylene grafted with maleic anhydride: B2, Coase Chemical Co., Ltd.

[0037] Examples 1-5

[0038] This embodiment and comparative example provide a series of composite PP-R pipe materials, including a PP-R inner layer, an impact-resistant oxygen barrier layer and a PP-R outer layer connected sequentially from the inside to the outside; the raw materials of the impact-resistant oxygen barrier layer are shown in Table 1 by weight.

[0039] Table 1

[0040]

[0041] The material of both the inner and outer layers of the PP-R is random copolymer polypropylene 1#, and the thickness ratio of the inner layer, the impact-resistant oxygen barrier layer and the outer layer of the PP-R is 28:13:62.

[0042] The preparation method of the composite PP-R pipe material includes the following steps:

[0043] (1) After mixing poly(p-xylene) and polypropylene grafted maleic anhydride in a high-speed mixer, the mixture is fed into the main feed port through the metering system of a twin-screw extruder, and polyglycolic acid is fed into the secondary feed port through the metering system. The secondary feed port is separated from the main feed port by at least two sections of the cylinder. Finally, a low-temperature resistant and high-impact PP-R composite material is obtained through one extrusion. The extrusion process is as follows: conveying section temperature 90-180℃, melting section temperature 150-230℃, homogenization section temperature 160-230℃, die temperature 160-230℃, and screw speed 100-150 rpm.

[0044] (2) The raw materials of the PP-R inner layer, the impact-resistant oxygen barrier layer and the PP-R outer layer are co-extruded and shaped to obtain the composite PP-R pipe material; the extrusion process is as follows: conveying section temperature 90~180℃, melting section temperature 160~230℃, homogenization section temperature 160~230℃, die temperature 180~230℃, screw speed 90~120rpm.

[0045] Example 6

[0046] A composite PP-R pipe material differs from Example 1 in that the thickness ratio of the PP-R inner layer, the impact-resistant oxygen barrier layer, and the PP-R outer layer in this example is 25:9:56.

[0047] Example 7

[0048] A composite PP-R pipe material differs from Example 1 in that both the inner and outer layers of the PP-R are made of random copolymer polypropylene 2#.

[0049] Comparative Example 1

[0050] A composite PP-R pipe material, differing from Example 1 in that: the raw material of the impact-resistant oxygen barrier layer described in this comparative example does not contain polyglycolic acid, and specifically comprises, by weight:

[0051] 160 parts of parylene and 20 parts of polypropylene grafted with maleic anhydride.

[0052] Comparative Example 2

[0053] A composite PP-R pipe material, differing from Example 1 in that: the raw material of the impact-resistant oxygen barrier layer described in this comparative example does not contain parylene, and specifically comprises, by weight:

[0054] 160 parts of polyglycolic acid and 20 parts of polypropylene grafted with maleic anhydride.

[0055] Comparative Example 3

[0056] A composite PP-R pipe material, differing from Example 1 in that: the impact-resistant oxygen barrier layer described in this comparative example specifically comprises, by weight, the following components:

[0057] 80 parts of parylene, 80 parts of polyglycolic acid, and 20 parts of polypropylene grafted with maleic anhydride.

[0058] Performance testing

[0059] The composite PP-R pipe materials of Examples 1-7 and Comparative Examples 1-2 were subjected to the following tests, and the results are shown in Table 2.

[0060] -15℃ and -5℃ impact tests: The test method refers to the standard GB / T18743-2002 Simple Supported Beam Impact Test Method for Thermoplastic Pipes for Fluid Transportation.

[0061] 20℃ and 95℃ hydrostatic pressure test: The test method refers to the standard GB / T18742.2-2017 Polypropylene piping systems for hot and cold water - Part 2 Pipes.

[0062] Oxygen permeability test: The test method refers to the standard ISO 17455-2005 Determination of oxygen permeability in multi-layered barrier pipes of plastic piping systems.

[0063] Table 2

[0064]

[0065]

[0066] The results show that the composite PP-R pipe prepared by this invention exhibited 100% no breakage in the impact test at -15℃ / -5℃, and showed no cracking or leakage in the hydrostatic test, with an oxygen permeability of 0.08 g / (m³). 3 ·d) and below, it has excellent low-temperature impact resistance, compressive strength and gas barrier properties.

[0067] Compared to Example 1, the composite PP-R pipe of Comparative Example 1 showed no breakage in 14 out of 20 tests at -15°C, and its oxygen permeability was as high as 1.52 g / (m³). 3 ·d) indicates that when the raw material of the impact-resistant oxygen barrier layer does not contain polyglycolic acid, it fails to effectively improve the low-temperature brittleness of PP-R pipes, resulting in poor low-temperature impact resistance and low gas barrier properties.

[0068] The raw material for the impact-resistant oxygen barrier layer in Comparative Example 2 does not contain parylene. The composite PP-R pipe prepared from this material showed only 12 / 20 pipes that did not break during the -15℃ impact test, and its oxygen permeability was as high as 1.80 g / (m²). 3 ·d), its low-temperature impact resistance is poor and its gas barrier properties are low.

[0069] The mass ratio of polyglycolic acid to parylene in Comparative Example 3 was too high, resulting in a decrease in its low-temperature impact resistance and gas barrier properties.

[0070] The above embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A composite PP-R pipe material, characterized in that, It includes a PP-R inner layer, an impact-resistant oxygen barrier layer, and a PP-R outer layer connected sequentially from the inside out. The impact-resistant oxygen barrier layer comprises the following components in parts by weight: 120 parts of parylene, 20-60 parts of polyglycolic acid, and 12-30 parts of compatibilizer.

2. The composite PP-R pipe material according to claim 1, characterized in that, The compatibilizer is maleic anhydride-grafted polypropylene.

3. The composite PP-R pipe material according to claim 1, characterized in that, The impact-resistant oxygen barrier layer comprises the following components in parts by weight: 120 parts of parylene, 20-40 parts of polyglycolic acid, and 14-24 parts of compatibilizer.

4. The composite PP-R pipe material according to claim 1, characterized in that, The thickness ratio of the inner PP-R layer, the impact-resistant oxygen barrier layer and the outer PP-R layer is (24-29):(8-14):(55-65).

5. The composite PP-R pipe material according to claim 1, characterized in that, The melt flow rate of the PP-R inner and outer layer materials is 0.2-0.3 g / 10 min at 230℃ and 2.16 kg.

6. The composite PP-R pipe material according to claim 1, characterized in that, The intrinsic viscosity of the poly(p-xylene) is 0.6-1.2 dl / g.

7. The composite PP-R pipe material according to claim 1, characterized in that, The intrinsic viscosity of the polyglycolic acid is 1.0-1.7 dl / g.

8. A method for preparing the composite PP-R pipe material according to any one of claims 1-7, characterized in that, Includes the following steps: (1) After mixing parylene and compatibilizer evenly, add polyglycolic acid for melt blending and extrusion to obtain impact-resistant oxygen barrier layer material; (2) The raw materials of the PP-R inner layer, the impact-resistant oxygen barrier layer and the PP-R outer layer are co-extruded and shaped to obtain composite PP-R pipe material.

9. The preparation method according to claim 8, characterized in that, In step (1), the melting temperature is 140-230℃.

10. The application of the composite PP-R pipe material according to any one of claims 1-7 in the preparation of low-temperature impact-resistant pipes.

Images