Composite PP-R pipe material as well as preparation method and application thereof

Abstract

The invention discloses a composite PP-R pipe material and a preparation method and application thereof, and relates to the technical field of PP-R pipes, the composite PP-R pipe material comprises a PP-R inner layer, an anti-impact oxygen barrier layer and a PP-R outer layer which are sequentially connected from inside to outside, and the anti-impact oxygen barrier layer comprises poly-p-xylene, polyglycolic acid and a compatilizer. According to the composite PP-R pipe material, the anti-impact oxygen-resistant layer is added to serve as a middle layer, the anti-impact oxygen-resistant layer is made of materials through cooperation of poly-p-xylylene and polyglycolic acid (PGA), the excellent mechanical property and gas barrier property are achieved, the structural performance can be kept stable in the low-temperature environment of-10 DEG C or below, and the service life of the composite PP-R pipe material is prolonged. The PP-R pipe material can be applied to a PP-R pipe material system so as to improve the low-temperature brittleness and improve the low-temperature impact resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of PP-R pipes, and more specifically, to a composite PP-R pipe material and a preparation method and application thereof. Background Art

[0002] The PP-R pipe industry is showing a trend of rapid development. Since ordinary PP-R pipes have extremely low oxygen barrier properties, they are prone to breed microorganisms after long-term use, affecting water quality and hygiene. Therefore, people's requirements for the oxygen barrier properties of PP-R pipes are gradually increasing. In addition, when the ambient temperature drops, the toughness of PP-R pipes will drop sharply. When the ambient temperature is below 0°C, PP-R exhibits typical brittle fracture phenomena, which makes PP-R pipes prone to pipe bursts in cold climates. At the same time, they are also more susceptible to damage during transportation and storage, greatly 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 technical difficulties that must be solved in the development of high-performance PP-R pipes.

[0003] The low-temperature toughened PP-R pipe in the prior art mainly adds β nucleating agent into the pipe, introduces nucleating agent, improves the crystallization rate of PP-R pipe, induces PP-R pipe to generate more β crystals, and at the same time achieves the effect of refining crystal size, accelerating crystallization rate, and increasing crystallization temperature, reducing the internal stress caused by different cooling speeds of the inner and outer layers of PP-R pipe, thereby improving the impact resistance of PP-R pipe, greatly improving the low-temperature toughness of PP-R pipe, and reducing the damage or rupture of PP-R pipe in northern regions. However, the use of β nucleating agent to improve PP-R pipe can often only improve the impact resistance of the material at around 0°C, and the effect of improving the impact resistance at lower temperatures is not significant, and it cannot improve the oxygen barrier performance of PP-R pipe. Summary of the invention

[0004] The purpose of the present 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 the PP-R pipe while taking into account the oxygen barrier property.

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

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

[0007] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0008] The present invention protects a composite PP-R pipe material, comprising a PP-R inner layer, an anti-impact oxygen barrier layer and a PP-R outer layer connected in sequence from the inside to the outside.

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

[0010] The composite PP-R pipe material of the present 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 material of the impact-resistant oxygen barrier layer adopts the mutual cooperation of polyparaxylene and polyglycolic acid (PGA). The material has excellent mechanical properties and gas barrier properties, and can maintain stable structural properties under low temperature environments below -10°C. It can be applied to the PP-R pipe system to improve its low-temperature brittleness and improve low-temperature impact resistance. At the same time, a compatibilizer is introduced to improve the interface adhesion between the impact-resistant oxygen barrier layer and the PP-R material, improve compatibility, and facilitate the stable existence of the impact-resistant oxygen barrier layer in the PP-R pipe system.

[0011] Among them, polyglycolic acid has excellent gas barrier properties and low-temperature ductility, and can maintain stable structural performance in low-temperature environments, but is easy to decompose in high-temperature and humid environments; polyparaxylene has excellent heat resistance, weather resistance and chemical stability; at the same time, its special polyxylene structure can coat polyglycolic acid, and it is easy to form a micron-level film in the molten state, and optimize the ratio of polyglycolic acid and polyxylene to obtain a film material with high gas barrier properties, strong low-temperature impact resistance and excellent mechanical properties.

[0012] In some embodiments, the mass fraction of the polyparaxylene in the oxygen-barrier layer is not less than 60 wt %.

[0013] In some embodiments, the compatibilizer is polypropylene grafted with maleic anhydride. The compatibilizer is beneficial to improving the thermal bonding performance of the anti-impact oxygen barrier layer and PP-R.

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

[0015] In some embodiments, the thickness ratio of the PP-R inner layer, the impact 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 PP-R inner layer and the PP-R outer layer have a melt flow rate of 0.1-0.5 g / 10 min, preferably 0.2-0.3 g / 10 min, at 230° C. and 2.16 kg.

[0017] In some embodiments, the intrinsic viscosity of the polyparaxylene 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] The present invention protects a method for preparing a composite PP-R pipe material, comprising the following steps:

[0020] (1) After polyparaxylene and a compatibilizer are uniformly mixed, polyglycolic acid is added thereto for melt blending, and then extruded to obtain an impact-resistant oxygen barrier layer material;

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

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

[0023] Preferably, the melting zone temperature is 150-230°C.

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

[0025] The present invention protects the use of a composite PP-R pipe material in the preparation of low-temperature impact-resistant pipes. The composite PP-R pipe material can be used in cold climates below 0°C, is not prone to pipe bursting, has high safety during transportation and storage, and improves the application scenarios and geographical scope of PP-R pipes.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention provides a composite PP-R pipe material, in which an impact-resistant oxygen barrier layer is used as an intermediate layer. The material of the impact-resistant oxygen barrier layer is a compound of polyparaxylene and polyglycolic acid, has excellent mechanical properties and gas barrier properties, and can maintain stable structural performance in a low temperature environment below -10°C. It can be applied to a PP-R pipe system to improve its low-temperature brittleness and improve its low-temperature impact resistance. DETAILED DESCRIPTION

[0028] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, 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 is 0.26 g / 10 min at 230°C and 2.16 kg; PA14D, Xuzhou Haitian Petrochemical Co., Ltd.

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

[0032] Polyparaxylene 1#: intrinsic viscosity is 1.0dl / g; Shenzhen Fangcunda Technology Co., Ltd.

[0033] Polyparaxylene 2#: intrinsic viscosity is 0.8dl / g; Jiangsu Runfeng Synthetic Technology Co., Ltd.

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

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

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

[0037] Embodiments 1 to 5

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

[0039] Table 1

[0040]

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

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

[0043] (1) After polyparaxylene and polypropylene grafted maleic anhydride are mixed in a high-speed mixer, they are fed into a main feeding port through a metering system of a twin-screw extruder, and polyglycolic acid is fed into a secondary feeding port through a metering system, wherein the secondary feeding port is spaced from the main feeding port by at least 2 barrel sections, and finally a PP-R composite material with low temperature resistance and high impact resistance is obtained through one extrusion; the extrusion process is as follows: the temperature of the conveying section is 90-180°C, the temperature of the melting section is 150-230°C, the temperature of the homogenizing section is 160-230°C, the temperature of the die is 160-230°C, and the screw speed is 100-150rpm.

[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 a composite PP-R pipe material; the extrusion process is: the conveying section temperature is 90-180°C, the melting section temperature is 160-230°C, the homogenizing section temperature is 160-230°C, the die temperature is 180-230°C, and the screw speed is 90-120rpm.

[0045] Example 6

[0046] A composite PP-R pipe material is different from Example 1 in that the thickness ratio of the PP-R inner layer, the impact 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, which is different from Example 1 in that the materials of the PP-R inner layer and the PP-R outer layer are both random copolymer polypropylene 2#.

[0049] Comparative Example 1

[0050] A composite PP-R pipe material, which is different from Example 1 in that the raw materials of the anti-impact oxygen barrier layer in this comparative example do not contain polyglycolic acid, and specifically include, by weight:

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

[0052] Comparative Example 2

[0053] A composite PP-R pipe material, which is different from Example 1 in that the raw materials of the anti-impact oxygen barrier layer in this comparative example do not contain polyparaxylene, and specifically include, by weight:

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

[0055] Comparative Example 3

[0056] A composite PP-R pipe material, which is different from Example 1 in that: the anti-impact oxygen barrier layer in this comparative example specifically comprises, by weight:

[0057] 80 parts of polyparaxylene, 80 parts of polyglycolic acid, and 20 parts of polypropylene grafted 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. The results are shown in Table 2.

[0060] -15℃, -5℃ impact test: The test method refers to the standard GB / T18743-2002 Simple supported beam impact test method for thermoplastic pipes for fluid transportation.

[0061] 20℃, 95℃ hydrostatic test: The test method refers to the standard GB / T18742.2-2017 Polypropylene piping system 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 of multi-layer pipes and barrier pipes in plastic piping systems.

[0063] Table 2

[0064]

[0065]

[0066] The results show that the composite PP-R pipe prepared by the present invention has 100% no cracks in the impact test under -15℃ / -5℃, no cracks and no leakage in the hydrostatic test, and the oxygen permeability is 0.08g / (m 3 ·d) or below, with excellent low-temperature impact resistance, compressive strength and gas barrier properties.

[0067] Compared with Example 1, the composite PP-R pipe of Comparative Example 1 has only 14 / 20 unbroken in the -15°C impact test, and the oxygen permeability is as high as 1.52g / (m 3 ·d), indicating that when the raw material of the impact-resistant oxygen barrier layer does not contain polyglycolic acid, the low-temperature brittleness of the PP-R pipe cannot be effectively improved, the low-temperature impact resistance is poor, and the gas barrier property is low.

[0068] The raw material of the anti-impact oxygen barrier layer of Comparative Example 2 does not contain polyparaxylene. The prepared composite PP-R pipe has only 12 / 20 cracks in the -15℃ impact test, and the oxygen permeability is as high as 1.80g / (m 3 ·d), its low temperature impact resistance is poor and its gas barrier property is low.

[0069] The mass ratio of polyglycolic acid to polyparaxylene in Comparative Example 3 is too high, and its low-temperature impact resistance and gas barrier properties are reduced.

[0070] The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope 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 anti-impact oxygen barrier layer and a PP-R outer layer connected in sequence from the inside to the outside. The anti-impact oxygen barrier layer comprises the following components in parts by weight: 120 parts of polyparaxylene, 20-60 parts of polyglycolic acid, and 12-30 parts of a compatibilizer.

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

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

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

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

6. The composite PP-R pipe material according to claim 1, characterized in that: The intrinsic viscosity of the polyparaxylene 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 to 7, characterized in that: The following steps are involved: (1) After polyparaxylene and a compatibilizer are uniformly mixed, polyglycolic acid is added thereto for melt blending, and then extruded to obtain an impact-resistant oxygen barrier layer material; (2) The raw materials of the PP-R inner layer, the anti-impact oxygen barrier layer and the PP-R outer layer are co-extruded and shaped to obtain a 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°C.

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

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