Polyphenylene sulfide pipe and preparation method thereof

Abstract

The invention discloses a polyphenylene sulfide pipe and a preparation method thereof, and relates to the technical field of high polymer materials, the pipe comprises the following components by weight: 60-100 parts of polyphenylene sulfide, 10-40 parts of a flexibilizer, 0.01-0.2 part of an antioxidant, and 2-5 parts of carbon black master batch. A dual toughening method is innovatively adopted, firstly, an oil-gas-medium-resistant bio-based elastomer is selected as a toughening agent, the source is green, 10% of petroleum-based synthetic rubber is replaced, carbon is reduced by 720,000 tons, and after the resin is toughened and makes contact with the oil-gas medium for a long time, the toughness of the resin is kept stable. And secondly, in the forming process of the pipe, the crystallization behavior of the pipe is regulated and controlled by controlling the cooling rate after the pipe is extruded, and the purpose of secondary toughening is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a polyphenylene sulfide pipe and a preparation method thereof. Background Art

[0002] Polyphenylene sulfide (PPS) has now achieved domestic production of raw materials at a price of 60,000 to 80,000 yuan per ton, about half of the imported materials, and has been widely used in the fields of electronics, automobiles, machinery and chemicals. However, there have been no reports on pipe products based on domestic PPS resins. The main reason is that two major technical problems limit the application of PPS in the field of pipes for oil and gas fields. On the one hand, the performance of PPS resin is insufficient. The performance of domestic PPS resin is compared with the thermoplastic plastic pipe materials commonly used in domestic oil fields, such as HDPE, PA and PVDF. It is found that PPS resin has obvious advantages in strength, modulus and temperature resistance, but its toughness is significantly different from that of the other three materials, and it cannot meet the requirements of material toughness for processes such as internal insertion and flanging during the application of pipes; on the other hand, the extrusion molding process of pipes with specifications above DN40 is immature, which restricts the application of PPS materials in the field of pipes. In the existing technical solutions, the PPS toughening agent has poor resistance to oil and gas media. After toughening, the resin is in long-term contact with the oil and gas medium and is easily extracted, resulting in poor toughening effect, which cannot meet the requirements for the use of oil and gas pipeline materials.

[0003] In order to cope with the corrosion problem of metal pipelines and ensure the normal production of oil and gas, the demand for non-metallic pipelines in my country's surface oil fields continues to increase. By the end of 2021, the group company has applied more than 42,000 kilometers of various types of non-metallic pipes, accounting for about 13% of the total surface pipelines, of which the usage in some oil fields has exceeded 20%. In 2017, non-metallic pipeline technology was listed as one of the top ten disruptive and leapfrog technologies of CNPC. At present, the demand for high-temperature resistant non-metallic pipes above 80°C in domestic oil fields is 400-500km / year, while the temperature resistance of my country's existing mature non-metallic pipe special materials for oil and gas gathering and transportation can only reach 60°C. CNPC is setting up a special development for 60-80°C non-metallic pipe special materials. However, all the special materials for high-temperature resistant non-metallic pipes above 80°C rely on imports, and the price is very expensive. It is urgent to develop high-temperature resistant, cost-effective and domestically produced non-metallic pipes.

[0004] PPS has now achieved domestic raw material prices of 60,000 to 80,000 yuan per ton, about half of the imported materials, and is widely used in the fields of electronics, automobiles, machinery and chemicals. Therefore, PPS has great potential to be developed into a special material for high-temperature resistant pipes for oil and gas fields. However, there are no reports on pipe products based on domestic PPS resins. The main reason is that two major technical problems limit the application of PPS in the field of pipes for oil and gas fields. On the one hand, the performance of PPS resin is insufficient. The performance of domestic PPS resin is compared with the commonly used thermoplastic plastic pipe materials in domestic oil fields, such as HDPE, PA and PVDF. It is found that PPS resin has obvious advantages in strength, modulus and temperature resistance, but its toughness is significantly different from that of the other three materials, and it cannot meet the requirements of material toughness for processes such as internal insertion and flanging during the application of pipes; on the other hand, the extrusion molding process of pipes with specifications above DN40 is immature, which restricts the application of PPS materials in the field of pipes. Based on the above background, this scheme provides toughening modification of high-temperature resistant PPS pipes for oil and gas fields and molding technology for pipes above DN40.

[0005] In the existing technical solutions, the PPS toughening agent has poor resistance to oil and gas media. After toughening, the resin is in contact with the oil and gas medium for a long time and is easily extracted, resulting in a deterioration of the toughening effect and being unable to meet the requirements for the use of oil and gas pipeline materials. Summary of the invention

[0006] The object of the present invention is to provide a polyphenylene sulfide pipe and a preparation method thereof, which greatly improves the toughening effect of PPS. To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a polyphenylene sulfide pipe, which comprises the following components by weight:

[0008] 60 to 100 parts of polyphenylene sulfide,

[0009] 10 to 40 parts of toughening agent,

[0010] 0.01-0.2 parts of antioxidant,

[0011] 2 to 5 parts of carbon black masterbatch.

[0012] Preferably, the polyphenylene sulfide is a high molecular weight linear polyphenylene sulfide resin with a weight average molecular weight of 50,000 to 70,000.

[0013] Preferably, the toughening agent is an epoxy-functionalized bio-based furoate elastomer; wherein the Mooney viscosity is 40±5ML(1+4)100°C, the mass content of furoate is not less than 50%, and the mass content of the third monomer containing the epoxy functional group is not less than 2%.

[0014] Preferably, the antioxidant consists of a primary antioxidant and an auxiliary antioxidant; wherein the weight ratio of the primary antioxidant to the auxiliary antioxidant is 1:(0.5-5), the primary antioxidant is antioxidant 1010, and the auxiliary antioxidant is antioxidant 168.

[0015] Preferably, the carbon black masterbatch contains 40-45% carbon black, 50% inorganic filler and 5-10% resin carrier.

[0016] Preferably, the inorganic filler is calcium carbonate with a fineness of 1000 mesh.

[0017] Preferably, the resin carrier is a low molecular weight linear polyphenylene sulfide resin with a weight average molecular weight of 10,000 to 30,000.

[0018] The present invention also provides a method for preparing a polyphenylene sulfide pipe, the method comprising the following steps:

[0019] Step S1, premixing the raw materials in a high-speed mixer according to proportion, with the speed of the high-speed mixer not less than 400 r / min and the mixing time not less than 30 min to obtain a premix;

[0020] Step S2, drying the premix;

[0021] Step S3, melt-blending and extruding the dried premixed material through a conical counter-rotating twin-screw extruder to obtain a pipe;

[0022] Step S4, cooling the tube after extrusion through a temperature-controlled gradient;

[0023] Step S5, cutting the pipe cooled to room temperature into fixed lengths to obtain a high-toughness polyphenylene sulfide pipe.

[0024] Preferably, in step S2, the drying conditions are: drying temperature is 120-130° C., and drying time is 2-3 hours.

[0025] Preferably, in step S3, the extruder barrel temperature and the extrusion head temperature are set in six stages to 155-160°C, 240-260°C, 290-310°C, 290-310°C, 290-310°C and 300-310°C, the screw speed is 20-30r / min, and the extrusion pressure is 3-7MPa.

[0026] Preferably, in step S4, the temperature-controlled gradient cooling is as follows: the temperature of the cooling medium in the first stage vacuum sizing box is 240-260°C, the temperature of the second stage spray box is 150-200°C, and the temperature of the third stage spray box is room temperature cooling water.

[0027] Technical effects and advantages of the present invention:

[0028] The present invention innovatively adopts a double heat-increasing method. First, a bio-based toughening agent resistant to oil and gas media is selected. It is green in source and replaces 10% of petroleum-based synthetic rubber, reducing carbon emissions by 720,000 tons. After toughening, the toughness of the resin remains stable after long-term contact with oil and gas media. Secondly, during the pipe forming process, the cooling rate of the pipe after extrusion is controlled to regulate the crystallization behavior of the pipe, thereby achieving the purpose of secondary toughening.

[0029] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. DETAILED DESCRIPTION

[0030] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0031] In order to solve the deficiencies of the prior art, the present invention discloses a high-toughness polyphenylene sulfide pipe toughened by a bio-based elastomer. The high-toughness polyphenylene sulfide pipe is prepared by extrusion molding after polyphenylene sulfide is modified by a toughening agent, and comprises the following components by weight:

[0032] 60 to 100 parts of polyphenylene sulfide,

[0033] 10 to 40 parts of toughening agent,

[0034] 0.01-0.2 parts of antioxidant,

[0035] 2 to 5 parts of carbon black masterbatch.

[0036] Furthermore, the polyphenylene sulfide is a high molecular weight linear polyphenylene sulfide resin with a weight average molecular weight of 50,000 to 70,000.

[0037] Furthermore, the toughening agent is an epoxy-functionalized bio-based furoate elastomer; wherein the Mooney viscosity is 40±5ML(1+4)100°C, the mass content of furoate is not less than 50%, and the mass content of the third monomer containing the epoxy functional group is not less than 2%.

[0038] Furthermore, the antioxidant consists of a primary antioxidant and an auxiliary antioxidant; wherein the weight ratio of the primary antioxidant to the auxiliary antioxidant is 1:(0.5-5), the primary antioxidant is antioxidant 1010, and the auxiliary antioxidant is antioxidant 168.

[0039] Furthermore, the carbon black masterbatch contains 40-45% carbon black, 50% inorganic filler and 5-10% resin carrier.

[0040] Furthermore, the inorganic filler is calcium carbonate with a fineness of 1000 mesh.

[0041] Furthermore, the resin carrier is a low molecular weight linear polyphenylene sulfide resin with a weight average molecular weight of 10,000 to 30,000.

[0042] The present invention also discloses a method for preparing a high-toughness polyphenylene sulfide pipe toughened by a bio-based elastomer, the method comprising the following steps:

[0043] Step S1, premix the raw materials in a high-speed mixer according to proportion, with the speed of the high-speed mixer not less than 400r / min and the mixing time not less than 30min to obtain a premix.

[0044] Step S2: drying the premix at a temperature of 120 to 130° C. for 2 to 3 hours.

[0045] Step S3, melt-blending and extruding the dried premixed material through a conical counter-rotating twin-screw extruder, and setting the six-stage extruder barrel temperature and the extrusion head temperature to 155-160°C, 240-260°C, 290-310°C, 290-310°C, 290-310°C and 300-310°C in stages, the screw speed is 20-30r / min, and the extrusion pressure is 3-7MPa to obtain a pipe.

[0046] Step S4, after the tube is extruded, it is subjected to temperature-controlled gradient cooling, the temperature of the cooling medium in the first section of the vacuum sizing box is 240-260°C, the temperature of the second section of the spray box is 150-200°C, and the temperature of the third section of the spray box is room temperature cooling water.

[0047] Step S5, cutting the pipe cooled to room temperature into fixed lengths to obtain a high-toughness polyphenylene sulfide pipe.

[0048] Embodiment 1:

[0049] Embodiment 1 of the present invention discloses a high-toughness polyphenylene sulfide pipe toughened by a bio-based elastomer, wherein the pipe comprises the following components by weight:

[0050] 60 parts of polyphenylene sulfide, wherein the weight average molecular weight of the polyphenylene sulfide is 50,000.

[0051] 10 parts of a toughening agent, wherein the toughening agent is an epoxy-functionalized bio-based furoate elastomer; wherein the Mooney viscosity is 40±5ML(1+4)100°C, the furoate mass content is 60%, and the mass content of the third monomer containing an epoxy functional group is 2.5%.

[0052] 0.01 parts of an antioxidant, wherein the antioxidant consists of a primary antioxidant and an auxiliary antioxidant; wherein the weight ratio of the primary antioxidant to the auxiliary antioxidant is 1:1, the primary antioxidant is antioxidant 1010, and the auxiliary antioxidant is antioxidant 168.

[0053] 2 parts of carbon black masterbatch, wherein the carbon black content of the carbon black masterbatch is 40%, the inorganic filler content is 50%, and the resin carrier content is 10%.

[0054] The present invention also discloses a method for preparing a high-toughness polyphenylene sulfide pipe toughened by a bio-based elastomer, the method comprising the following steps:

[0055] Step S1, premix the raw materials in a high-speed mixer according to proportion, with the high-speed mixer rotating at 400 r / min and the mixing time at 30 min to obtain a premix.

[0056] Step S2: drying the premix at a temperature of 120° C. for 2 h.

[0057] Step S3, melt-blending and extruding the dried premix using a conical counter-rotating twin-screw extruder, and setting the six-stage extruder barrel temperature and the extrusion head temperature to 155°C, 240°C, 290°C, 290°C, 290°C and 300°C in stages, the screw speed is 20r / min, and the extrusion pressure is 3MPa to obtain a pipe.

[0058] Step S4, after the tube is extruded, it is subjected to temperature-controlled gradient cooling, the temperature of the cooling medium in the first section of the vacuum sizing box is 240°C, the temperature of the second section of the spray box is 150°C, and the temperature of the third section of the spray box is room temperature cooling water.

[0059] Step S5, cutting the pipe cooled to room temperature into fixed lengths to obtain a high-toughness polyphenylene sulfide pipe.

[0060] Embodiment 2:

[0061] 65 parts of polyphenylene sulfide, wherein the weight average molecular weight of the polyphenylene sulfide is 70,000.

[0062] 30 parts of a toughening agent, wherein the toughening agent is an epoxy-functionalized bio-based furoate elastomer; wherein the Mooney viscosity is 40±5ML(1+4)100°C, the furoate mass content is 60%, and the mass content of the third monomer containing the epoxy functional group is 3%.

[0063] 0.1 parts of antioxidant, the antioxidant consists of a main antioxidant and an auxiliary antioxidant; wherein the weight ratio of the main antioxidant to the auxiliary antioxidant is 1:1.2, the main antioxidant is antioxidant 1010, and the auxiliary antioxidant is antioxidant 168.

[0064] 3 parts of carbon black masterbatch, wherein the carbon black content of the carbon black masterbatch is 45%, the inorganic filler content is 50%, and the resin carrier content is 5%.

[0065] The present invention also discloses a method for preparing a high-toughness polyphenylene sulfide pipe toughened by a bio-based elastomer, the method comprising the following steps:

[0066] Step S1, premix the raw materials in a high-speed mixer according to proportion, with the high-speed mixer rotating at 450 r / min and the mixing time at 40 min to obtain a premix.

[0067] Step S2: drying the premix at a temperature of 125° C. for 2.5 h.

[0068] Step S3, melt-blending and extruding the dried premix using a conical counter-rotating twin-screw extruder, and setting the six-stage extruder barrel temperature and the extrusion head temperature to 157°C, 250°C, 300°C, 300°C, 305°C and 310°C in stages, the screw speed is 25r / min, and the extrusion pressure is 5MPa to obtain a pipe.

[0069] Step S4, after the tube is extruded, it is subjected to temperature-controlled gradient cooling, the temperature of the cooling medium in the first section of the vacuum sizing box is 245°C, the temperature of the second section of the spray box is 170°C, and the temperature of the third section of the spray box is room temperature cooling water.

[0070] Step S5, cutting the pipe cooled to room temperature into fixed lengths to obtain a high-toughness polyphenylene sulfide pipe.

[0071] Embodiment 3:

[0072] 100 parts of polyphenylene sulfide, wherein the weight average molecular weight of the polyphenylene sulfide is 70,000.

[0073] 40 parts of a toughening agent, wherein the toughening agent is an epoxy-functionalized bio-based furoate elastomer; wherein the Mooney viscosity is 40±5ML(1+4)100°C, the mass content of furoate is 65%, and the mass content of the third monomer containing the epoxy functional group is 3%.

[0074] 0.2 parts of antioxidant, the antioxidant consists of a main antioxidant and an auxiliary antioxidant; wherein the weight ratio of the main antioxidant to the auxiliary antioxidant is 1:2, the main antioxidant is antioxidant 1010, and the auxiliary antioxidant is antioxidant 168.

[0075] 5 parts of carbon black masterbatch, wherein the carbon black content of the carbon black masterbatch is 45%, the inorganic filler content is 50%, and the resin carrier content is 5%.

[0076] The present invention also discloses a method for preparing a high-toughness polyphenylene sulfide pipe toughened by a bio-based elastomer, the method comprising the following steps:

[0077] Step S1, premix the raw materials in a high-speed mixer according to proportion, with the high mixer speed of 500r / min and the mixing time of 40min to obtain a premix.

[0078] Step S2: drying the premix at a temperature of 130° C. for 3 h.

[0079] Step S3, melt-blending and extruding the dried premix using a conical counter-rotating twin-screw extruder, and setting the six-stage extruder barrel temperature and the extrusion head temperature to 160°C, 260°C, 300°C, 305°C, 310°C and 310°C in stages, the screw speed is 30r / min, and the extrusion pressure is 7MPa to obtain a pipe.

[0080] Step S4, after the tube is extruded, it is subjected to temperature-controlled gradient cooling, the temperature of the cooling medium in the first section of the vacuum sizing box is 260°C, the temperature of the second section of the spray box is 200°C, and the temperature of the third section of the spray box is room temperature cooling water.

[0081] Step S5, cutting the pipe cooled to room temperature into fixed lengths to obtain a high-toughness polyphenylene sulfide pipe.

[0082] Comparative Example 1:

[0083] A method for preparing a pure polyphenylene sulfide pipe, the method comprising the following steps:

[0084] Step S1, drying the pure polyphenylene sulfide resin at a temperature of 125° C. for 2.5 hours.

[0085] Step S2, melt-extrude the dried pure polyphenylene sulfide resin using a conical counter-rotating twin-screw extruder, and set the six-stage extruder barrel temperature and extrusion head temperature to 155°C, 240°C, 290°C, 295°C, 300°C and 305°C in stages, the screw speed is 20r / min, and the extrusion pressure is 3MPa to obtain a pipe.

[0086] Step S3, after the tube is extruded, it is subjected to temperature-controlled gradient cooling, the temperature of the cooling medium in the first section of the vacuum sizing box is 240°C, the temperature of the second section of the spray box is 150°C, and the temperature of the third section of the spray box is room temperature cooling water.

[0087] Step S4, cutting the pipe cooled to room temperature into fixed lengths to obtain pure polyphenylene sulfide pipes.

[0088] Test example:

[0089] With reference to GBT 8804.1-2003 Determination of tensile properties of thermoplastic pipes Part 1 General principles of test methods, the tensile mechanical properties of the pipes were tested. The test results are shown in the table below.

[0090] Table 1 Comparative Example 1 Tensile Mechanical Properties Test of Pure Polyphenylene Sulfide Pipe

[0091]

[0092]

[0093] Table 2 Tensile mechanical properties test of polyphenylene sulfide pipe toughened by bio-based elastomer in Example 1

[0094] Sample No. Elongation at break (%) Yield strength (MPa) Elastic modulus(GPa) 1 57.6 44.4 1.9 2 61.4 44.4 2.0 3 47.6 45.7 2.0 4 51.3 42.5 1.8 5 58.3 44.5 2.1 average value 55.2 44.3 2.0

[0095] Table 3 Tensile mechanical properties test of polyphenylene sulfide pipe toughened with bio-based elastomer in Example 2

[0096] Sample No. Elongation at break (%) Yield strength (MPa) Elastic modulus(GPa) 1 47.6 43.2 1.8 2 51.1 44.1 2.1 3 47.6 45.1 1.9 4 50.3 43.5 1.8 5 48.3 44.5 2.1 average value 49.0 44.1 1.9

[0097] Table 4 Tensile mechanical properties test of polyphenylene sulfide pipe toughened by bio-based elastomer in Example 3

[0098]

[0099]

[0100] Comparing the test results in Tables 2 to 4 with Table 1, it can be seen that after toughening with bio-based elastomers, the toughness of the pipe is significantly improved, as shown by a significant increase in the elongation at break. The increase in toughness leads to a decrease in yield strength and elastic modulus, but the yield strength and elastic modulus after toughening are still higher than those of thermoplastics currently used in oil fields, meeting the requirements of SY / T 7415-2018.

[0101] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A polyphenylene sulfide pipe, characterized in that: The pipe comprises the following components by weight: 60 to 100 parts of polyphenylene sulfide, 10 to 40 parts of toughening agent, 0.01-0.2 parts of antioxidant, 2 to 5 parts of carbon black masterbatch.

2. A polyphenylene sulfide pipe according to claim 1, characterized in that: The polyphenylene sulfide is a high molecular weight linear polyphenylene sulfide resin with a weight average molecular weight of 50,000 to 70,000.

3. A polyphenylene sulfide pipe according to claim 1 or 2, characterized in that: The toughening agent is an epoxy-functionalized bio-based furoate elastomer; wherein the Mooney viscosity is 40±5ML(1+4)100°C, the mass content of furoate is not less than 50%, and the mass content of the third monomer containing the epoxy functional group is not less than 2%.

4. A polyphenylene sulfide pipe according to claim 2, characterized in that: The antioxidant consists of a main antioxidant and an auxiliary antioxidant; wherein the weight ratio of the main antioxidant to the auxiliary antioxidant is 1:(0.5-5), the main antioxidant is antioxidant 1010, and the auxiliary antioxidant is antioxidant 168.

5. The polyphenylene sulfide pipe according to claim 1, characterized in that: The carbon black masterbatch contains 40-45% carbon black, 50% inorganic filler and 5-10% resin carrier.

6. A polyphenylene sulfide pipe according to claim 5, characterized in that: The inorganic filler is calcium carbonate with a fineness of 1000 mesh.

7. The polyphenylene sulfide pipe according to claim 5, characterized in that: The resin carrier is a low molecular weight linear polyphenylene sulfide resin with a weight average molecular weight of 10,000 to 30,000.

8. A method for preparing a polyphenylene sulfide pipe according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: Step S1, premixing the raw materials in a high-speed mixer according to proportion, with the speed of the high-speed mixer not less than 400 r / min and the mixing time not less than 30 min to obtain a premix; Step S2, drying the premix; Step S3, melt-blending and extruding the dried premixed material through a conical counter-rotating twin-screw extruder to obtain a pipe; Step S4, cooling the tube by temperature control gradient after extrusion; Step S5, cutting the pipe cooled to room temperature into fixed lengths to obtain a high-toughness polyphenylene sulfide pipe.

9. The method for preparing a polyphenylene sulfide pipe according to claim 8, characterized in that: In step S2, the drying conditions are: drying temperature is 120-130°C, and drying time is 2-3h.

10. The method for preparing a polyphenylene sulfide pipe according to claim 9, characterized in that: In step S3, the extruder barrel temperature and the extrusion head temperature are set in six stages: 155-160°C, 240-260°C, 290-310°C, 290-310°C, 290-310°C and 300-310°C, the screw speed is 20-30r / min, and the extrusion pressure is 3-7MPa.

11. The method for preparing a polyphenylene sulfide pipe according to claim 9, characterized in that: In step S4, the temperature-controlled gradient cooling is as follows: the temperature of the cooling medium in the first stage vacuum sizing box is 240-260°C, the temperature of the second stage spray box is 150-200°C, and the temperature of the third stage spray box is normal temperature cooling water.

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