High-strength PP-R glass fiber reinforced pipe and preparation method thereof

Abstract

The invention relates to the technical field of plastic pipes, and provides a high-strength PP-R glass fiber reinforced pipe and a preparation method thereof. The high-strength PP-R glass fiber reinforced pipe is prepared from the following components in parts by weight: 80 to 90 parts of polypropylene random copolymer, 2 to 10 parts of glass fiber, 5 to 12 parts of composite metal oxide, 8 to 10 parts of flexibilizer, 0.5 to 1 part of organic nucleating agent and 1 to 2 parts of antioxidant, the preparation method of the composite metal oxide comprises the following steps: mixing a metal nitrate solution and an organic acid for the first time, adding an ionic liquid, mixing for the second time, carrying out a self-propagating combustion reaction, washing, and drying to obtain the composite metal oxide. By means of the technical scheme, the problem that the longitudinal shrinkage rate of the PP-R glass fiber reinforced pipe is high in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic pipes, and in particular to a high-strength PP-R glass fiber reinforced pipe and a preparation method thereof. Background Art

[0002] Polypropylene random copolymer (PP-R) fiberglass-reinforced pipes are widely used in hot and cold water piping systems. PP-R material is reinforced with glass fiber, increasing its rigidity and strength, enabling it to withstand greater pressure and external forces. However, in current practical applications, PP-R fiberglass-reinforced pipes still suffer from high longitudinal shrinkage.

[0003] Too high a longitudinal shrinkage rate can lead to a series of serious consequences. During the pipeline installation process, a high longitudinal shrinkage rate causes the size of the pipe to change during the installation process, making it difficult to accurately connect the pipe, reducing the sealing of the connection, and easily causing leakage, affecting the normal operation of the entire pipeline system. In addition, during long-term use, due to changes in the temperature of the hot and cold water pipes, the internal stress generated by the longitudinal shrinkage will continue to act on the pipe. Over time, it may cause deformation, cracks and other problems in the pipe, thereby reducing the service life of the pipe.

[0004] Therefore, it is necessary to develop a PP-R glass fiber reinforced tube with low longitudinal shrinkage. Summary of the Invention

[0005] The present invention provides a high-strength PP-R glass fiber reinforced pipe and a preparation method thereof, which solves the problem of high longitudinal shrinkage of the PP-R glass fiber reinforced pipe in the related art.

[0006] The technical solutions of the present invention are as follows: The present invention provides a high-strength PP-R glass fiber reinforced tube, comprising the following components in parts by weight: 80-90 parts of random copolymer polypropylene, 2-10 parts of glass fiber, 5-12 parts of composite metal oxide, 8-10 parts of toughening agent, 0.5-1 part of organic nucleating agent, and 1-2 parts of antioxidant; The preparation method of the composite metal oxide comprises the following steps: The metal nitrate solution and the organic acid are mixed for the first time, the ionic liquid is added and mixed for the second time, and then a self-propagating combustion reaction is carried out, followed by washing and drying to obtain a composite metal oxide.

[0007] As a further technical solution, the raw materials of the metal nitrate solution include metal nitrate and water in a mass volume ratio of 1g:2~4mL; The organic acid includes one or both of citric acid and glycine, preferably glycine; The ionic liquid includes 1-ethyl-3-methylimidazolium dinitrile amide salt.

[0008] Among the components of the high-strength PP-R glass fiber reinforced tube of the present invention, when preparing the composite metal oxide, organic acids include citric acid, glycine, etc., which serve as fuel for preparing the composite metal oxide by the solution combustion method, complex with metal ions, effectively control the dispersion of metal ions during the combustion process, and promote the formation of uniform and fine composite metal oxide particles. After being added to the PP-R glass fiber reinforced tube, it is beneficial to reduce the longitudinal shrinkage rate of the PP-R glass fiber reinforced tube.

[0009] As a further technical solution, the metal nitrate includes one or both of cobalt nitrate and zinc nitrate.

[0010] As a further technical solution, when the metal nitrate includes cobalt nitrate and zinc nitrate, the mass ratio of the cobalt nitrate to the zinc nitrate is 4:1~4.

[0011] Among the components of the high-strength PP-R glass fiber reinforced tube of the present invention, when preparing the composite metal oxide, cobalt nitrate and zinc nitrate are used as metal nitrate precursors of the metal oxide. Compared with the use of cobalt nitrate or zinc nitrate alone, the use of cobalt nitrate and zinc nitrate as metal oxide precursors reduces the longitudinal shrinkage of the PP-R glass fiber reinforced tube, especially when the mass ratio of cobalt nitrate to zinc nitrate is 4:1-4, and also improves the impact strength of the PP-R glass fiber reinforced tube.

[0012] As a further technical solution, the mass ratio of the metal nitrate to the organic acid is 3:0.6-0.8; The mass ratio of the metal nitrate to the ionic liquid is 5:1-2.

[0013] As a further technical solution, the stirring speed during the first mixing is 300-500 rpm, and the stirring time is 5-8 min; The stirring speed during the second mixing is 200-400 rpm, and the stirring time is 4-6 minutes.

[0014] As a further technical solution, the random copolymer polypropylene includes one or more of random copolymer polypropylene PA14D, random copolymer polypropylene 4220, and random copolymer polypropylene 200P.

[0015] As a further technical solution, the organic nucleating agent includes one or both of nucleating agent TMB-5 and nucleating agent BT-5.

[0016] Among the components of the high-strength PP-R glass fiber reinforced tube of the present invention, when the organic nucleating agent is the nucleating agent TMB-5, it is a β-crystal nucleating agent, which can induce the random copolymer polypropylene to mainly form β crystals during the crystallization process, thereby ensuring the mechanical properties and stability of the PP-R glass fiber reinforced tube; When the organic nucleating agent is the nucleating agent BT-5, it can accelerate the crystallization rate of random copolymer polypropylene, so that the molecular chains of random copolymer polypropylene are arranged in an orderly manner to form crystals in a relatively short period of time, thereby accelerating the crystallization speed and avoiding the dimensional changes caused by continued slow crystallization during storage at room temperature, thereby ensuring the dimensional stability of the PP-R glass fiber reinforced tube.

[0017] As a further technical solution, the organic nucleating agent includes nucleating agent TMB-5 and nucleating agent BT-5 in a mass ratio of 1:1.

[0018] The antioxidant includes one or more of hindered phenol antioxidants, amine antioxidants, and phosphite antioxidants.

[0019] The random copolymer polypropylene used as the base material for the high-strength PP-R glass fiber reinforced tube in this invention contains a large number of tertiary carbon atoms in its molecular structure. Since hydrogen atoms on these tertiary carbon atoms are relatively reactive, they are easily captured by factors such as heat, light, oxygen, and mechanical stress during processing, leading to oxidative degradation. Therefore, the addition of an antioxidant inhibits or delays the oxidation process of the random copolymer polypropylene, ensuring the stable performance and service life of the PP-R glass fiber reinforced tube. Among them, hindered phenol antioxidants can be, for example, antioxidant 1010, antioxidant 1076, antioxidant 264, etc.; amine antioxidants can be, for example, antioxidant 6PPD, etc.; phosphite antioxidants can be, for example, antioxidant 168, antioxidant 626, antioxidant TPP, etc.

[0020] As a further technical solution, the toughening agent includes a polyolefin elastomer.

[0021] As a further technical solution, the model of the polyolefin elastomer includes one or more of DF610, DF710, and DF740.

[0022] As a further technical solution, the diameter of the glass fiber is 5-12 μm, for example, 5 μm, 10 μm, 11 μm, 12 μm, preferably 10 μm.

[0023] As a further technical solution, the length of the glass fiber is 0.5-1.5 mm, for example, 0.5 mm, 1 mm, 1.5 mm, preferably 1.5 mm.

[0024] As a further technical solution, the particle size of the composite metal oxide is 30-40 nm, for example, 30 nm, 35 nm, 40 nm, preferably 30 nm.

[0025] The present invention also provides a method for preparing a high-strength PP-R glass fiber reinforced tube, which is used to prepare the high-strength PP-R glass fiber reinforced tube, comprising the following steps: The components of the high-strength PP-R glass fiber reinforced pipe are mixed, dried, extruded into a pipe blank, and cooled and shaped to obtain the high-strength PP-R glass fiber reinforced pipe.

[0026] The working principle and beneficial effects of the present invention are: In the present invention, a composite metal oxide prepared by a self-propagating combustion reaction of a metal nitrate solution, an organic acid and an ionic liquid is added to the PP-R glass fiber reinforced tube, which significantly reduces the longitudinal shrinkage of the PP-R glass fiber reinforced tube. In the prior art, metal oxides are often directly added to the PP-R glass fiber reinforced tube. In the present invention, a metal nitrate solution is used as a precursor of the metal oxide, an organic acid is used as a fuel, and an ionic liquid is used as a nitrogen source and a carbon source. A nitrogen-carbon composite metal oxide is prepared by a self-propagating combustion reaction, wherein nitrogen and carbon atoms enhance the interatomic force of the metal oxide and improve the stability of the metal oxide. After being added to the PP-R glass fiber reinforced tube, the metal oxide is evenly distributed inside the matrix of the PP-R glass fiber reinforced tube to form a It is a heterogeneous nucleation point, which can effectively limit the thermal motion of the PPR molecular chain and inhibit the shrinkage trend caused by temperature changes. At the same time, the metal oxide composited with nitrogen and carbon has better dispersibility, avoiding the problem of local shrinkage differences caused by easy agglomeration of ordinary metal oxides added to the PP-R glass fiber reinforced pipe matrix. Therefore, in the present invention, the composite metal oxide prepared by the self-propagating combustion reaction of metal nitrate solution, organic acid and ionic liquid is added to the PP-R glass fiber reinforced pipe. By improving the dispersibility and stability of the metal oxide, the longitudinal shrinkage rate of the PP-R glass fiber reinforced pipe is significantly reduced, and its shape and size can be better maintained, reducing the problems of loosening and leakage of the pipeline connection parts caused by longitudinal shrinkage. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples, the ionic liquid is 1-ethyl-3-methylimidazolium dinitrile amide salt with a purity of 98%.

[0029] Example 1 A high-strength PP-R glass fiber reinforced tube comprising the following components in parts by weight: 80 parts of random copolymer polypropylene (model PA14D), 2 parts of glass fiber (diameter 12 μm, length 1.5 mm), 5 parts of composite metal oxide, 8 parts of polyolefin elastomer (POE, polyolefin thermoplastic elastomer DF610), 0.5 parts of nucleating agent TMB-5, and 1 part of antioxidant 168; The preparation method of the composite metal oxide comprises the following steps: Mix zinc nitrate hexahydrate and water at a mass volume ratio of 1 g:2 mL to obtain a zinc nitrate hexahydrate solution; A zinc nitrate hexahydrate solution and glycine were mixed at a stirring speed of 300 rpm for 8 minutes, an ionic liquid was added, and the mixture was mixed at a stirring speed of 200 rpm for 6 minutes, followed by heating to concentrate a colloid, which was further heated to expand and then spontaneously undergo a self-propagating combustion reaction for 60 seconds, and then washed, dried, and pulverized to obtain a composite metal oxide with a particle size of 35 nm; wherein the mass ratio of zinc nitrate hexahydrate to glycine was 3:0.6; and the mass ratio of zinc nitrate hexahydrate to ionic liquid was 5:1; The preparation method of high-strength PP-R glass fiber reinforced pipe comprises the following steps: The components of the high-strength PP-R glass fiber reinforced pipe are mixed, dried at 80°C for 20 minutes, extruded into a tube billet, pulled into a vacuum spray water tank for vacuum cooling and shaping, and then again put into a vacuum spray water tank for cooling. The tube billet is pulled out, spray-typed and coded, and cut to obtain a high-strength PP-R glass fiber reinforced pipe with an average outer diameter of 40.2 mm and a wall thickness of 5.6 mm.

[0030] Example 2 A high-strength PP-R glass fiber reinforced tube comprising the following components in parts by weight: 90 parts of random copolymer polypropylene (model PA14D), 10 parts of glass fiber (5 μm in diameter and 0.5 mm in length), 12 parts of composite metal oxide, 9 parts of polyolefin elastomer (POE, polyolefin thermoplastic elastomer DF710), 1 part of nucleating agent TMB-5, 1 part of antioxidant 1010, and 1 part of antioxidant 168; The preparation method of the composite metal oxide comprises the following steps: Mix zinc nitrate hexahydrate and water at a mass volume ratio of 1 g:4 mL to obtain a zinc nitrate hexahydrate solution; A zinc nitrate hexahydrate solution and citric acid were mixed at a stirring speed of 500 rpm for 5 minutes, an ionic liquid was added, and the mixture was mixed at a stirring speed of 400 rpm for 4 minutes, followed by heating to concentrate a colloid, which was further heated to expand and then spontaneously undergo a self-propagating combustion reaction for 60 seconds, and then washed, dried, and crushed to obtain a composite metal oxide with a particle size of 40 nm; wherein the mass ratio of zinc nitrate hexahydrate to citric acid was 3:0.8; and the mass ratio of zinc nitrate hexahydrate to ionic liquid was 5:2; The preparation method of high-strength PP-R glass fiber reinforced pipe comprises the following steps: The components of the high-strength PP-R glass fiber reinforced pipe are mixed, dried at 80°C for 30 minutes, extruded into a tube billet, pulled into a vacuum spray water tank for vacuum cooling and shaping, and then again put into a vacuum spray water tank for cooling. The tube billet is pulled out, spray-typed and coded, and cut to obtain a high-strength PP-R glass fiber reinforced pipe with an average outer diameter of 40.3 mm and a wall thickness of 5.7 mm.

[0031] Example 3 A high-strength PP-R glass fiber reinforced tube comprising the following components in parts by weight: 60 parts of random copolymer polypropylene (model PA14D), 25 parts of random copolymer polypropylene (model 200P), 6 parts of glass fiber (diameter 10 μm, length 1.5 mm), 8 parts of composite metal oxide, 10 parts of polyolefin elastomer (POE, polyolefin thermoplastic elastomer DF610), 0.4 parts of nucleating agent TMB-5, 0.4 parts of nucleating agent BT-5, and 1.5 parts of antioxidant 1010; The preparation method of the composite metal oxide comprises the following steps: Cobalt nitrate hexahydrate and water were mixed at a mass volume ratio of 1 g:3 mL to obtain a cobalt nitrate hexahydrate solution; A cobalt nitrate hexahydrate solution and glycine were mixed at a stirring speed of 400 rpm for 6 minutes, an ionic liquid was added, and the mixture was mixed at a stirring speed of 300 rpm for 5 minutes. The mixture was then heated to concentrate a colloid, and the colloid was further heated to expand and then spontaneously undergo a self-propagating combustion reaction for 60 seconds. The colloid was washed, dried, and crushed to obtain a composite metal oxide with a particle size of 30 nm. The mass ratio of cobalt nitrate hexahydrate to glycine was 3:0.7, and the mass ratio of cobalt nitrate hexahydrate to ionic liquid was 5:1.5. The preparation method of high-strength PP-R glass fiber reinforced pipe comprises the following steps: The components of the high-strength PP-R glass fiber reinforced pipe are mixed, dried at 80°C for 30 minutes, extruded into a tube billet, pulled into a vacuum spray water tank for vacuum cooling and shaping, and then again put into a vacuum spray water tank for cooling. The tube billet is pulled out, spray-typed and coded, and cut to obtain a high-strength PP-R glass fiber reinforced pipe with an average outer diameter of 40.3 mm and a wall thickness of 5.6 mm.

[0032] Example 4 The only difference between this embodiment and embodiment 3 is that cobalt nitrate hexahydrate is replaced by zinc nitrate hexahydrate, that is, the preparation method of the composite metal oxide includes the following steps: Mix zinc nitrate hexahydrate and water at a mass volume ratio of 1 g:3 mL to obtain a zinc nitrate hexahydrate solution; A zinc nitrate hexahydrate solution and glycine were mixed at a stirring speed of 400 rpm for 6 minutes, an ionic liquid was added and mixed at a stirring speed of 300 rpm for 5 minutes, and then heated to concentrate a colloid. The colloid was further heated to expand and then spontaneously undergo a self-propagating combustion reaction for 60 seconds. The colloid was washed, dried, and crushed to obtain a composite metal oxide with a particle size of 30 nm. The mass ratio of zinc nitrate hexahydrate to glycine was 3:0.7, and the mass ratio of zinc nitrate hexahydrate to ionic liquid was 5:1.5.

[0033] Example 5 The only difference between this embodiment and embodiment 3 is that the preparation method of the composite metal oxide includes the following steps: Mixing metal nitrate and water at a mass volume ratio of 1 g:3 mL to obtain a metal nitrate solution; A metal nitrate solution and glycine are mixed at a stirring speed of 400 rpm for 6 minutes, an ionic liquid is added and mixed at a stirring speed of 300 rpm for 5 minutes, and then heated to concentrate a colloid. The colloid is further heated to expand and then spontaneously undergo a self-propagating combustion reaction for 60 seconds. The colloid is washed, dried, and crushed to obtain a composite metal oxide with a particle size of 30 nm. The mass ratio of the metal nitrate to glycine is 3:0.7; the mass ratio of the metal nitrate to the ionic liquid is 5:1.5; and the metal nitrate is cobalt nitrate hexahydrate and zinc nitrate hexahydrate in a mass ratio of 5:1.

[0034] Example 6 The only difference between this embodiment and embodiment 5 is that the metal nitrate is cobalt nitrate hexahydrate and zinc nitrate hexahydrate in a mass ratio of 4:5.

[0035] Example 7 The only difference between this embodiment and embodiment 5 is that the metal nitrate is cobalt nitrate hexahydrate and zinc nitrate hexahydrate in a mass ratio of 1:1.

[0036] Example 8 The only difference between this embodiment and embodiment 5 is that the metal nitrate is cobalt nitrate hexahydrate and zinc nitrate hexahydrate in a mass ratio of 4:1.

[0037] Comparative Example 1 The only difference between this comparative example and Example 3 is that the composite metal oxide is replaced by cobalt oxide with a particle size of 30 nm.

[0038] Comparative Example 2 The only difference between this comparative example and Example 3 is that no ionic liquid is added during the preparation of the composite metal oxide.

[0039] Experimental Example 1 The high-strength PP-R glass fiber reinforced pipes prepared in Examples 1 to 8 and Comparative Examples 1 to 2 were tested for longitudinal shrinkage in accordance with the standard GB / T 18742.2-2017 "Polypropylene Piping Systems for Hot and Cold Water Part 2: Pipes". Method B - oven test was used. The test conditions were: 135±2°C, 1 h. The results are shown in Table 1 below.

[0040] Table 1 Performance test results

[0041] Compared with Comparative Examples 1-2, the longitudinal shrinkage of the PP-R glass fiber reinforced tubes prepared in Examples 1-8 is lower, indicating that the use of metal nitrate solution as a precursor of the metal oxide, organic acid as a fuel, and ionic liquid as a nitrogen source and carbon source to prepare the nitrogen-carbon composite metal oxide through a self-propagating combustion reaction significantly reduces the longitudinal shrinkage of the PP-R glass fiber reinforced tube.

[0042] Experimental Example 2 According to the standard GB / T1043.1-2008 "Determination of the impact properties of plastics - Part 1: Non-instrumented impact test", the high-strength PP-R glass fiber reinforced pipes prepared in Examples 5 to 8 were subjected to the simple supported beam notched impact strength test. The test temperature was 0°C and the notch type was A-type notch. The results are shown in Table 2 below.

[0043] Table 2 Performance test results

[0044] Compared with Examples 5 and 6, the PP-R glass fiber reinforced pipes prepared in Examples 7 and 8 have higher simply supported beam notched impact strength, indicating that when preparing the composite metal oxide, the metal nitrate uses cobalt nitrate and zinc nitrate as precursors of the metal oxide, and the mass ratio of cobalt nitrate to zinc nitrate is 4:1-4, which improves the impact strength of the PP-R glass fiber reinforced pipe.

[0045] Experimental Example 3 The high-strength PP-R glass fiber reinforced pipe prepared in Example 3 was tested in accordance with the standard GB / T 18742.2-2017 "Polypropylene Piping Systems for Hot and Cold Water Part 2: Pipes". The results are shown in Table 3 below.

[0046] Table 3 Performance test results

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-strength PP-R glass fiber reinforced pipe, characterized in that: The invention comprises the following components in parts by weight: 80-90 parts of random copolymer polypropylene, 2-10 parts of glass fiber, 5-12 parts of composite metal oxide, 8-10 parts of toughening agent, 0.5-1 part of organic nucleating agent, and 1-2 parts of antioxidant; The preparation method of the composite metal oxide comprises the following steps: The metal nitrate solution and the organic acid are mixed for the first time, the ionic liquid is added and mixed for the second time, and then a self-propagating combustion reaction is carried out, followed by washing and drying to obtain a composite metal oxide.

2. The high-strength PP-R glass fiber reinforced pipe according to claim 1, characterized in that: The raw materials of the metal nitrate solution include metal nitrate and water in a mass volume ratio of 1g:2~4mL; The organic acid includes one or both of citric acid and glycine; The ionic liquid includes 1-ethyl-3-methylimidazolium dinitrile amide salt.

3. The high-strength PP-R glass fiber reinforced pipe according to claim 2, characterized in that: The metal nitrate includes one or both of cobalt nitrate and zinc nitrate.

4. The high-strength PP-R glass fiber reinforced pipe according to claim 3, characterized in that: When the metal nitrate comprises cobalt nitrate and zinc nitrate, the mass ratio of the cobalt nitrate to the zinc nitrate is 4:1-4.

5. The high-strength PP-R glass fiber reinforced pipe according to claim 3, characterized in that: The mass ratio of the metal nitrate to the organic acid is 3:0.6-0.8; The mass ratio of the metal nitrate to the ionic liquid is 5:1-2.

6. The high-strength PP-R glass fiber reinforced pipe according to claim 1, characterized in that: The stirring speed during the first mixing is 300-500 rpm, and the stirring time is 5-8 min; The stirring speed during the second mixing is 200-400 rpm, and the stirring time is 4-6 minutes.

7. The high-strength PP-R glass fiber reinforced pipe according to claim 1, characterized in that: The random copolymer polypropylene includes one or more of random copolymer polypropylene PA14D, random copolymer polypropylene 4220, and random copolymer polypropylene 200P.

8. The high-strength PP-R glass fiber reinforced pipe according to claim 1, characterized in that: The organic nucleating agent includes one or both of nucleating agent TMB-5 and nucleating agent BT-5; The antioxidant includes one or more of hindered phenol antioxidants, amine antioxidants, and phosphite antioxidants; The toughening agent includes a polyolefin elastomer.

9. The high-strength PP-R glass fiber reinforced pipe according to claim 1, characterized in that: The diameter of the glass fiber is 5-12 μm and the length is 0.5-1.5 mm; the particle size of the composite metal oxide is 30-40 nm.

10. A method for preparing a high-strength PP-R glass fiber reinforced tube, for preparing the high-strength PP-R glass fiber reinforced tube according to any one of claims 1 to 9, characterized in that: The following steps are involved: The components of the high-strength PP-R glass fiber reinforced pipe are mixed, dried, extruded into a pipe blank, and cooled and shaped to obtain the high-strength PP-R glass fiber reinforced pipe.

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