Nylon pipeline as well as preparation method and application thereof

Abstract

The invention discloses a nylon pipeline as well as a preparation method and application thereof, belongs to the technical field of nylon pipelines, and solves the problem that bursting pressure, hydrolysis resistance and surface performance of a nylon pipeline in the prior art are difficult to consider at the same time. The nylon pipeline comprises an inner layer, a middle layer and an outer layer which are sequentially arranged from inside to outside. On the basis of the mass of the middle layer, the middle layer comprises the following components: 60-99 wt% of a second base material, 0.1-30 wt% of a chain extender, 0-30 wt% of a second flexibilizer, 0-4 wt% of a second antioxidant, 0-3 wt% of a second light stabilizer, 0-3 wt% of a second lubricant and 0-3 wt% of a second coloring agent; and the second base material is nylon. The nylon pipeline disclosed by the invention has good appearance, bursting pressure performance, hydrolysis resistance and processability.

Description

Technical Field

[0001] The invention belongs to the technical field of nylon pipelines, and in particular relates to a nylon pipeline and a preparation method and application thereof. Background Art

[0002] Nylon (PA) is a type of polymer containing amide groups (-CO-NH-) in its molecular chain. It is currently the engineering plastic with the largest output and the widest application field. Because its molecular chain contains amide groups, it can form hydrogen bonds, and its molecular chain structure is regular, so it has high strength and modulus. According to the different molecular structures of nylon, it can be divided into aliphatic nylon and aromatic nylon. Among them, aliphatic nylon molecular chains are mainly methylene, with good toughness, excellent processing performance, and high cost performance. It has been widely used in aerospace, electrical equipment, automotive industry and other fields. The main varieties are PA6, PA66, PA1010, PA11, PA12, etc.

[0003] In order to improve the bursting pressure and hydrolysis resistance of nylon pipes, chain extenders need to be added. However, the conventional method of adding chain extenders results in a rough surface of the nylon pipe and severe precipitation at the die. The precipitation at the die will reduce the glossiness of the pipe surface and cause scratches on the pipe surface. At the same time, the precipitates will accumulate over a long period of time and fall onto the pipe to form defective products, which greatly limits the performance improvement and application scope of the product. It is difficult to promote and apply extruded products with high surface requirements. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the problem in the prior art that it is difficult to balance the bursting pressure, hydrolysis resistance and surface properties of nylon pipes, thereby providing a nylon pipe and a preparation method and application thereof.

[0005] To this end, the present invention provides the following technical solutions.

[0006] In a first aspect, the present invention provides a nylon pipe, comprising an inner layer, a middle layer and an outer layer arranged in sequence from the inside to the outside;

[0007] Based on the mass of the inner layer, the inner layer includes the following components: 60-99wt% of a first substrate, 0-20wt% of a first plasticizer, 0-25wt% of a first toughening agent, 0-4wt% of a first antioxidant, 0-3wt% of a first light stabilizer, 0-3wt% of a first lubricant, and 0-3wt% of a first colorant;

[0008] Based on the mass of the intermediate layer, the intermediate layer includes the following components: 60-99wt% of a second substrate, 0.1-30wt% of a chain extender, 0-30wt% of a second toughening agent, 0-4wt% of a second antioxidant, 0-3wt% of a second light stabilizer, 0-3wt% of a second lubricant, and 0-3wt% of a second colorant;

[0009] The second substrate is nylon;

[0010] Based on the mass of the outer layer, the outer layer includes the following components: 60-99wt% of a third substrate, 0-20wt% of a second plasticizer, 0-25wt% of a third toughening agent, 0-4wt% of a third antioxidant, 0-3wt% of a third light stabilizer, 0-3wt% of a third lubricant, and 0-3wt% of a third colorant.

[0011] Using plasticizers in the outer and inner layers can improve the fluidity of the resin, thereby obtaining a bright pipe appearance and avoiding material accumulation at the die. Not adding plasticizers to the middle layer can avoid a decrease in burst pressure and low-temperature impact performance.

[0012] In a possible implementation, the first substrate and the third substrate are both nylon;

[0013] Optionally, the ratio of the terminal carboxyl concentration (mmol / kg) to the terminal amino concentration (mmol / kg) of the nylon is eq-COOH / eq-NH2 is 1 to 20, preferably 2 to 15;

[0014] Optionally, the first substrate, the second substrate, and the third substrate are independently selected from one or more of PA6, PA66, PA1010, PA610, PA612, PA614, PA616, PA618, PA1010, PA1012, PA11, PA12, and PA1212;

[0015] Preferably, the first substrate, the second substrate, and the third substrate are the same;

[0016] Preferably, the inner layer has the same composition as the outer layer.

[0017] In a possible implementation, the chain extender includes one or more of isoepoxides, acid anhydrides, oxazolines, diisocyanates, and phosphites.

[0018] In a possible implementation, the outer diameter of the nylon tube is 4 to 30 mm, preferably 8 to 25 mm;

[0019] In a possible implementation, the wall thickness of the nylon pipe is 0.6 to 3 mm, preferably 1 to 2 mm;

[0020] In a possible implementation, the thickness of the inner layer is ≤ 15% of the total wall thickness of the nylon pipe, preferably 5-10%;

[0021] In a possible implementation manner, the thickness of the outer layer is ≤ 15% of the total wall thickness of the nylon pipe, preferably 5-10%.

[0022] In a possible implementation manner, based on the mass of the inner layer, the components in the inner layer satisfy at least one of the following conditions:

[0023] (1) The first substrate is 65 to 95 wt %;

[0024] (2) the first plasticizer is 0 to 15 wt %;

[0025] (3) the first toughening agent is 3 to 20 wt %;

[0026] (4) the first antioxidant is 0.1 to 2 wt %;

[0027] (5) the first light stabilizer is 0 to 2 wt %;

[0028] (6) the first lubricant is 0 to 2 wt %;

[0029] (7) The first colorant is 0 to 2 wt%.

[0030] In a possible implementation manner, based on the mass of the intermediate layer, the components of the intermediate layer satisfy at least one of the following conditions:

[0031] (1) The second substrate is 75 to 95 wt %;

[0032] (2) the chain extender is 0.1 to 10 wt %; optionally, the chain extender is 0.1 to 5 wt %;

[0033] (3) the second toughening agent is 3 to 25 wt %;

[0034] (4) the second antioxidant is 0.1 to 2 wt %;

[0035] (5) the second light stabilizer is 0 to 2 wt %;

[0036] (6) The second lubricant is 0 to 2 wt %;

[0037] (7) The second colorant is 0 to 2 wt%;

[0038] In a possible implementation manner, based on the mass of the outer layer, the components in the outer layer satisfy at least one of the following conditions:

[0039] (1) The third substrate is 65 to 95 wt %;

[0040] (2) the second plasticizer is 0 to 15 wt %;

[0041] (3) the third toughening agent is 3 to 20 wt %;

[0042] (4) the third antioxidant is 0.1 to 2 wt %;

[0043] (5) the third light stabilizer is 0 to 2 wt %;

[0044] (6) The third lubricant is 0 to 2 wt %;

[0045] (7) The third colorant is 0 to 2 wt%.

[0046] In a possible embodiment, the first toughening agent and / or the second toughening agent and / or the third toughening agent include thermoplastic elastomers;

[0047] Optionally, the thermoplastic elastomers include one or more of polyolefin elastomers and chemically grafted modified products thereof, thermoplastic polyurethane elastomers, nylon elastomers, EPDM rubber and grafted modified products thereof, polyolefins and grafted modified products thereof;

[0048] In a possible embodiment, the first antioxidant, the second antioxidant, and the third antioxidant are independently selected from one or more of phenols, amines, metal ion halides, thioesters, and phosphites;

[0049] In a possible embodiment, the first light stabilizer, the second light stabilizer, and the third light stabilizer are independently selected from one or more of ultraviolet light absorbers, free radical scavengers, and light shielding agents;

[0050] In a possible implementation, the first optical lubricant, the second lubricant, and the third lubricant are independently selected from one or more of stearic acid complex ester, polyethylene wax, amide wax, and polyol;

[0051] In a possible implementation, the first colorant, the second colorant, and the third colorant are independently selected from one or more of pigments, dyes, masterbatches, and carbon black;

[0052] In one possible embodiment, the first plasticizer and the second plasticizer are independently selected from at least one of N-butylbenzenesulfonamide, N,N-diallylbenzenesulfonamide, N,N-diallyl-4-methylbenzenesulfonamide, 4-methyl-N,N-di(prop-2-ynyl)benzenesulfonamide, and N-ethynyl-N,4-dimethylbenzenesulfonamide, preferably N-butylbenzenesulfonamide.

[0053] In a second aspect, the present invention provides a method for preparing a nylon pipe, comprising:

[0054] The raw materials of the inner layer, the middle layer and the outer layer are respectively extruded and granulated by a twin-screw extruder to obtain inner layer granules, middle layer granules and outer layer granules;

[0055] The inner layer pellets, the middle layer pellets and the outer layer pellets are respectively added into a three-layer co-extrusion extruder, and melt-extruded to obtain the nylon pipe;

[0056] Optionally, the extrusion temperature of the extrusion granulation is 180 to 270°C;

[0057] Optionally, in the twin-screw extruder, the first zone is 180-220°C, the second zone to the third zone is 190-250°C, the fourth zone to the sixth zone is 200-270°C, the seventh zone to the tenth zone is 210-270°C, the eleventh zone to the twelfth zone is 200-260°C, and the thirteenth zone is 190-240°C;

[0058] Optionally, the screw speed of the twin-screw extruder is 100-300 rpm, preferably 150-250 rpm.

[0059] In a third aspect, the present invention provides an application of the nylon pipe or the nylon pipe made according to the method in the fields of automobile pipes, cooling water pipes, and energy storage.

[0060] The technical solution of the present invention has the following advantages:

[0061] 1. The nylon pipe of the present invention comprises an inner layer, an intermediate layer and an outer layer arranged in sequence from the inside to the outside; based on the mass of the inner layer, the inner layer comprises the following components: 60-99wt% of a first base material, 0-20wt% of a first plasticizer, 0-25wt% of a first toughening agent, 0-4wt% of a first antioxidant, 0-3wt% of a first light stabilizer, 0-3wt% of a first lubricant, and 0-3wt% of a first colorant; based on the mass of the intermediate layer, the intermediate layer comprises the following components: 60-99wt% of a second base material, 0.1-30wt% of a chain extender, and 0.25wt% of a first toughening agent. wt%, a second toughening agent 0-30wt%, a second antioxidant 0-4wt%, a second light stabilizer 0-3wt%, a second lubricant 0-3wt%, and a second colorant 0-3wt%; the second substrate is nylon; based on the mass of the outer layer, the outer layer includes the following components: a third substrate 60-99wt%, a second plasticizer 0-20wt%, a third toughening agent 0-25wt%, a third antioxidant 0-4wt%, a third light stabilizer 0-3wt%, a third lubricant 0-3wt%, and a third colorant 0-3wt%.

[0062] The present invention sets the chain extender in the middle layer (that is, the material of the inner layer and the outer layer is a flexible modified substrate, and the middle layer is a nylon branched / cross-linked polymer), and through the appropriate addition ratio of each layer component, the problem of rough pipe surface caused by the difficulty of processing after nylon branching / cross-linking can be avoided while improving the bursting pressure and water resistance, and the outer layer and the inner layer are in contact with the mold, rather than the middle layer directly in contact with the mold, which can avoid the serious problem of die precipitation; the middle layer adopts a nylon branched / cross-linked structure, so that the thickness of the layer is thinned to a certain extent, avoiding the problem of too high melt strength and easy generation of weld marks when only a single layer is used, and the process window of the three-layer structure is wider and easier to form. The nylon pipeline of the present invention has good appearance, bursting pressure performance, hydrolysis resistance and processing performance.

[0063] 2. The first substrate, the second substrate, and the third substrate are the same, so that there is no clear stratification between the middle layer and the outer layer, and between the middle layer and the inner layer of the nylon pipe, there is no interface between the layers, and each layer has good compatibility.

[0064] 3. The preparation method of the nylon pipe of the present invention comprises: respectively extruding and granulating the raw materials of the inner layer, the middle layer and the outer layer by a twin-screw extruder to obtain inner layer pellets, middle layer pellets and outer layer pellets; respectively adding the inner layer pellets, middle layer pellets and outer layer pellets into a three-layer co-extrusion extruder, melt-extruded, and obtain the nylon pipe.

[0065] The nylon branched / cross-linked polymer is arranged in the middle layer, and the inner and outer layers are flexible modified nylon, which can avoid the problem of melt fracture during extrusion due to too high strength, and at the same time avoid problems such as rough product surface, severe precipitation, weld marks, and difficulty in molding.

[0066] The nylon pipe of the present invention realizes a multilayer structure by a co-extrusion method, and can be extruded into a smooth pipe, a corrugated pipe, a special-shaped pipe, etc. The pipe can be applied to fluid delivery pipes, such as cooling pipes, energy storage pipes, drainage pipes, air brake pipes, oil pipelines and other medium-resistant pipe fields. DETAILED DESCRIPTION

[0067] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0068] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be obtained commercially.

[0069] Source of raw materials:

[0070] PA12 resin: Wanamid L3000, Wanhua Chemical Group Co., Ltd.

[0071] PA610 resin: SMVO, Arkema.

[0072] Toughener: FUSABOND N493, Dow Chemical.

[0073] Toughening agent: MH5020C, Mitsui Chemicals.

[0074] Chain extender: isophorone diisocyanate, Wanhua Chemical Group Co., Ltd.

[0075] Chain extender: Styrene-acrylic acid multifunctional oligomeric chain extender, ADR-4368, BASF SE.

[0076] Plasticizer: N-butylbenzenesulfonamide, Shandong Suihua.

[0077] Antioxidant: Irganox 1098, BASF SE.

[0078] Antioxidant: Irganox 168, BASF SE.

[0079] Light stabilizer: UV-312, Rianlon.

[0080] Lubricant: Calcium stearate, Liyang Chemical.

[0081] Colorant: Black masterbatch, Cabot.

[0082] Example 1

[0083] This embodiment provides a method for preparing a nylon pipe, comprising:

[0084] 65kg L3000 resin, 5kg N-butylbenzenesulfonamide, 25kg toughening agent N493, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch were mixed uniformly in a high-speed mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C for zone 1, 210°C for zones 2-3, 250°C for zones 4-6, 250°C for zones 7-10, 240°C for zones 11-12, and 230°C for zone 13; the screw speed was 200rpm to obtain inner and outer layer materials.

[0085] 66kg L3000 resin, 4kg IPDI, 25kg toughening agent N493, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch are mixed evenly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder is 200°C for zone 1, 210°C for zones 2-3, 250°C for zones 4-6, 250°C for zones 7-10, 240°C for zones 11-12, and 230°C for zone 13; the screw speed is 200rpm to obtain an intermediate layer material.

[0086] A three-layer co-extrusion extruder was used to extrude the pipe, with an extrusion temperature of 250°C, an extrusion speed of 20m / min, a cooling temperature of 15°C, a vacuum pressure of 0.02MPa, and an outer diameter of 16mm and a wall thickness of 1.25mm. The inner layer thickness was 0.15mm, the middle layer thickness was 0.95mm, and the outer layer thickness was 0.15mm.

[0087] Example 2

[0088] 77kg L3000 resin, 18kg toughening agent MH5020C, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch were mixed uniformly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C for zone 1, 210°C for zones 2-3, 250°C for zones 4-6, 250°C for zones 7-10, 240°C for zones 11-12, and 230°C for zone 13; the screw speed was 200rpm to obtain inner and outer layer materials.

[0089] 75kg L3000 resin, 2kg ADR-4368, 18kg toughening agent MH5020C, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch were mixed uniformly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C in the first zone, 210°C in the second-third zones, 250°C in the fourth-sixth zones, 250°C in the seventh-tenth zones, 240°C in the eleventh-twelfth zones, and 230°C in the thirteenth zone. The screw speed was 200rpm to obtain an intermediate layer material.

[0090] A three-layer co-extrusion extruder was used to extrude the pipe, with an extrusion temperature of 250°C, an extrusion speed of 20m / min, a cooling temperature of 15°C, a vacuum pressure of 0.02MPa, and an outer diameter of 16mm and a wall thickness of 1.25mm. The inner layer thickness was 0.1mm, the middle layer thickness was 1.05mm, and the outer layer thickness was 0.1mm.

[0091] Example 3

[0092] 90kg SMVO resin, 5kg toughening agent N493, 500g antioxidant Irganox1098, 500g antioxidant Irgafos168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch were mixed uniformly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C for zone 1, 210°C for zones 2-3, 250°C for zones 4-6, 250°C for zones 7-10, 240°C for zones 11-12, and 230°C for zone 13; the screw speed was 200rpm to obtain inner and outer layer materials.

[0093] 89kg SMVO resin, 1kg ADR-4368, 5kg toughening agent N493, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch were mixed uniformly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C in the first zone, 210°C in the second-third zones, 250°C in the fourth-sixth zones, 250°C in the seventh-tenth zones, 240°C in the eleventh-twelfth zones, and 230°C in the thirteenth zone. The screw speed was 200rpm to obtain an intermediate layer material.

[0094] A three-layer co-extrusion extruder was used to extrude the pipe, with an extrusion temperature of 250°C, an extrusion speed of 20m / min, a cooling temperature of 15°C, a vacuum pressure of 0.02MPa, and an outer diameter of 16mm and a wall thickness of 1.25mm. The inner layer thickness was 0.05mm, the middle layer thickness was 1.05mm, and the outer layer thickness was 0.15mm.

[0095] Example 4

[0096] This embodiment provides a method for preparing a nylon pipe, comprising:

[0097] 75kg SMVO resin, 10kg N-butylbenzenesulfonamide, 5kg toughening agent N493, 2kg antioxidant Irganox1098, 2kg antioxidant Irgafos 168, 2kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 2kg black masterbatch were mixed uniformly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C for zone 1, 210°C for zones 2-3, 250°C for zones 4-6, 250°C for zones 7-10, 240°C for zones 11-12, and 230°C for zone 13; the screw speed was 200rpm to obtain inner and outer layer materials.

[0098] 76kg SMVO resin, 9kg IPDI, 5kg toughening agent N493, 2kg antioxidant Irganox1098, 2kg antioxidant Irgafos 168, 2kg light stabilizer UV-312, 2kg lubricant calcium stearate and 2kg black masterbatch were mixed evenly in a high mixer and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C for zone 1, 210°C for zones 2-3, 250°C for zones 4-6, 250°C for zones 7-10, 240°C for zones 11-12 and 230°C for zone 13. The screw speed was 200rpm to obtain an intermediate layer material.

[0099] A three-layer co-extrusion extruder was used to extrude the pipe, with an extrusion temperature of 250°C, an extrusion speed of 20m / min, a cooling temperature of 15°C, a vacuum pressure of 0.02MPa, and an outer diameter of 16mm and a wall thickness of 1.25mm. The inner layer thickness was 0.05mm, the middle layer thickness was 1.15mm, and the outer layer thickness was 0.05mm.

[0100] Comparative Example 1

[0101] This comparative example provides a method for preparing a nylon pipe, comprising:

[0102] 70kg L3000 resin, 10kg N-butylbenzenesulfonamide, 15kg toughening agent MH5020C, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch were mixed uniformly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C for the first zone, 210°C for the second-third zones, 250°C for the fourth-sixth zones, 250°C for the seventh-tenth zones, 240°C for the eleventh-twelfth zones, and 230°C for the thirteenth zone. The screw speed was 200rpm to obtain inner layer, middle layer and outer layer materials.

[0103] A three-layer co-extrusion extruder was used to extrude the pipe, with an extrusion temperature of 250°C, an extrusion speed of 20m / min, a cooling temperature of 15°C, a vacuum pressure of 0.02MPa, and an outer diameter of 16mm and a wall thickness of 1.25mm. The inner layer thickness was 0.15mm, the middle layer thickness was 0.95mm, and the outer layer thickness was 0.15mm.

[0104] Comparative Example 2

[0105] This comparative example provides a method for preparing a nylon pipe, comprising:

[0106] 61kg L3000 resin, 4kg IPDI, 5kg N-butylbenzenesulfonamide, 25kg toughening agent N493, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate and 1kg black masterbatch were mixed evenly in a high mixer and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C for zone 1, 210°C for zones 2-3, 250°C for zones 4-6, 250°C for zones 7-10, 240°C for zones 11-12 and 230°C for zone 13. The screw speed was 200rpm to obtain inner and outer layer materials.

[0107] 70kg L3000 resin, 25kg toughening agent N493, 500g antioxidant Irganox1098, 500g antioxidant Irgafos 168, 1kg light stabilizer UV-312, 2kg lubricant calcium stearate, and 1kg black masterbatch were mixed uniformly in a high mixer, and then added into a twin-screw extruder for extrusion granulation. The extrusion temperature of the twin-screw extruder was 200°C in the first zone, 210°C in the second-third zones, 250°C in the fourth-sixth zones, 250°C in the seventh-tenth zones, 240°C in the eleventh-twelfth zones, and 230°C in the thirteenth zone. The screw speed was 200rpm to obtain an intermediate layer material.

[0108] A three-layer co-extrusion extruder was used to extrude the pipe, with an extrusion temperature of 250°C, an extrusion speed of 20m / min, a cooling temperature of 15°C, a vacuum pressure of 0.02MPa, and an outer diameter of 16mm and a wall thickness of 1.25mm. The inner layer thickness was 0.15mm, the middle layer thickness was 0.95mm, and the outer layer thickness was 0.15mm.

[0109] The performance test results of the product of this embodiment are shown in Table 1.

[0110] Test example

[0111] The performance of the nylon pipes prepared in the embodiments and comparative examples was tested.

[0112] The bursting pressure of nylon pipe is measured according to GB16897.

[0113] Hydrolysis resistance: Soak the nylon pipe in 120℃ coolant for 1000h, then test the bursting pressure of the nylon pipe after soaking according to GB16897, and test the low-temperature impact performance of the nylon pipe at -30℃ according to PV3905.

[0114] Surface roughness: Use a 3D microscope to capture the microscopic morphology of the pipeline and measure the surface roughness.

[0115] Separation performance: Observe whether there is material precipitation at the die when extruding the pipeline.

[0116] The test results are shown in Table 1.

[0117] Table 1 Nylon pipe performance test results

[0118]

[0119] As can be seen from Table 1, by designing a three-layer pipeline structure and placing the chain extender in the middle layer, the bursting pressure and hydrolysis resistance of the product can be effectively improved while ensuring its processing performance as well as the surface performance and application performance of the product.

[0120] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. 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 implementation methods here. The obvious changes or modifications derived from these are still within the scope of protection of the invention.

Claims

1. A nylon pipeline, characterized in that: It includes an inner layer, a middle layer and an outer layer arranged in sequence from the inside to the outside; Based on the mass of the inner layer, the inner layer includes the following components: 60-99wt% of a first substrate, 0-20wt% of a first plasticizer, 0-25wt% of a first toughening agent, 0-4wt% of a first antioxidant, 0-3wt% of a first light stabilizer, 0-3wt% of a first lubricant, and 0-3wt% of a first colorant; Based on the mass of the intermediate layer, the intermediate layer includes the following components: 60-99wt% of a second substrate, 0.1-30wt% of a chain extender, 0-30wt% of a second toughening agent, 0-4wt% of a second antioxidant, 0-3wt% of a second light stabilizer, 0-3wt% of a second lubricant, and 0-3wt% of a second colorant; The second substrate is nylon; Based on the mass of the outer layer, the outer layer includes the following components: 60-99wt% of a third substrate, 0-20wt% of a second plasticizer, 0-25wt% of a third toughening agent, 0-4wt% of a third antioxidant, 0-3wt% of a third light stabilizer, 0-3wt% of a third lubricant, and 0-3wt% of a third colorant.

2. The nylon pipe according to claim 1, characterized in that: The first substrate and the third substrate are both nylon; Optionally, the ratio of the terminal carboxyl concentration to the terminal amino concentration of the nylon eq-COOH / eq-NH2 is 1 to 20, preferably 2 to 15; Optionally, the first substrate, the second substrate, and the third substrate are independently selected from one or more of PA6, PA66, PA1010, PA610, PA612, PA614, PA616, PA618, PA1010, PA1012, PA11, PA12, and PA1212; Preferably, the first substrate, the second substrate, and the third substrate are the same; Preferably, the inner layer has the same composition as the outer layer.

3. The nylon pipe according to claim 1, characterized in that: The chain extender includes one or more of isoepoxides, acid anhydrides, oxazolines, diisocyanates, and phosphites.

4. The nylon pipe according to claim 1, characterized in that: At least one of the following conditions is met: (1) The outer diameter of the nylon pipe is 4 to 30 mm, preferably 8 to 25 mm; (2) The wall thickness of the nylon pipe is 0.6 to 3 mm, preferably 1 to 2 mm; (3) The thickness of the inner layer is ≤ 15% of the total wall thickness of the nylon pipe, preferably 5-10%; (4) The thickness of the outer layer is ≤ 15% of the total wall thickness of the nylon pipe, preferably 5-10%.

5. The nylon pipe according to claim 1, characterized in that: Based on the mass of the inner layer, the components in the inner layer meet at least one of the following conditions: (1) The first substrate is 65 to 95 wt %; (2) the first plasticizer is 0 to 15 wt %; (3) the first toughening agent is 3 to 20 wt %; (4) the first antioxidant is 0.1 to 2 wt %; (5) the first light stabilizer is 0 to 2 wt %; (6) the first lubricant is 0 to 2 wt %; (7) The first colorant is 0 to 2 wt%.

6. The nylon pipe according to claim 1, characterized in that: Based on the mass of the intermediate layer, the components of the intermediate layer meet at least one of the following conditions: (1) The second substrate is 75 to 95 wt %; (2) the chain extender is 0.1 to 10 wt %; optionally, the chain extender is 0.1 to 5 wt %; (3) the second toughening agent is 3 to 25 wt %; (4) the second antioxidant is 0.1 to 2 wt %; (5) the second light stabilizer is 0 to 2 wt %; (6) The second lubricant is 0 to 2 wt %; (7) The second colorant is 0 to 2 wt%.

7. The nylon pipe according to claim 1, characterized in that: Based on the mass of the outer layer, the components in the outer layer meet at least one of the following conditions: (1) The third substrate is 65 to 95 wt %; (2) the second plasticizer is 0 to 15 wt %; (3) the third toughening agent is 3 to 20 wt %; (4) the third antioxidant is 0.1 to 2 wt %; (5) the third light stabilizer is 0 to 2 wt %; (6) The third lubricant is 0 to 2 wt %; (7) The third colorant is 0 to 2 wt%.

8. The nylon pipe according to claim 1, characterized in that: At least one of the following conditions is met: (1) The first toughening agent and / or the second toughening agent and / or the third toughening agent include thermoplastic elastomers; Optionally, the thermoplastic elastomers include one or more of polyolefin elastomers and chemically grafted modified products thereof, thermoplastic polyurethane elastomers, nylon elastomers, EPDM rubber and grafted modified products thereof, polyolefins and grafted modified products thereof; (2) the first antioxidant, the second antioxidant, and the third antioxidant are independently selected from one or more of phenols, amines, metal ion halides, thioesters, and phosphites; (3) the first light stabilizer, the second light stabilizer, and the third light stabilizer are independently selected from one or more of ultraviolet light absorbers, free radical scavengers, and light shielding agents; (4) the first optical lubricant, the second lubricant, and the third lubricant are independently selected from one or more of stearic acid complex ester, polyethylene wax, amide wax, and polyol; (5) the first colorant, the second colorant, and the third colorant are independently selected from one or more of pigments, dyes, masterbatches, and carbon black; (6) The first plasticizer and the second plasticizer are independently selected from at least one of N-butylbenzenesulfonamide, N,N-diallylbenzenesulfonamide, N,N-diallyl-4-methylbenzenesulfonamide, 4-methyl-N,N-di(prop-2-ynyl)benzenesulfonamide, and N-ethynyl-N,4-dimethylbenzenesulfonamide, preferably N-butylbenzenesulfonamide.

9. A method for preparing a nylon pipe according to any one of claims 1 to 8, characterized in that: include: The raw materials of the inner layer, the middle layer and the outer layer are respectively extruded and granulated by a twin-screw extruder to obtain inner layer granules, middle layer granules and outer layer granules; The inner layer pellets, the middle layer pellets and the outer layer pellets are respectively added into a three-layer co-extrusion extruder, and melt-extruded to obtain the nylon pipe; Optionally, the extrusion temperature of the extrusion granulation is 180 to 270°C; Optionally, in the twin-screw extruder, the first zone is 180-220°C, the second zone to the third zone is 190-250°C, the fourth zone to the sixth zone is 200-270°C, the seventh zone to the tenth zone is 210-270°C, the eleventh zone to the twelfth zone is 200-260°C, and the thirteenth zone is 190-240°C; Optionally, the screw speed of the twin-screw extruder is 100-300 rpm, preferably 150-250 rpm.

10. Use of the nylon pipe according to any one of claims 1 to 8 or the nylon pipe made according to the method according to claim 9 in the fields of automobile pipes, cooling water pipes and energy storage.

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