Easily stripped pipe and preparation method thereof

Abstract

The invention discloses an easy-to-peel pipe which adopts an ethylene-acrylate copolymer and a reinforcing agent as matrix resin, as ethylene-acrylate is a copolymer and contains an acrylate side group, the crystallization of ethylene-acrylate is disturbed, the distance between main chain vinyl molecules is increased, and the entanglement structure of the molecules is reduced; by adding the ethylene-acrylate copolymer, the cohesion strength of an ethylene-acrylate molecular chain is reduced, the tensile strength of the molecular structure can be improved by adding the reinforcing agent, and the orientation degree of the molecular chain in a blend of the ethylene-acrylate copolymer and the reinforcing agent is further controlled through an extrusion process to ensure that the orientation degree is within a certain range. The ethylene-acrylate copolymer and the reinforcing agent blend molecular chain and chain segment extend from a free curled disordered state to an orientation direction, so that the molecular entanglement structure is reduced, the tensile strength of the molecular structure is enhanced, the tearability of the pipe is realized, and the tensile strength of the pipe is improved.

Description

Technical Field

[0001] This invention relates to the field of pipe technology, and in particular to an easy-peel pipe and its preparation method. Background Technology

[0002] Easy-peel tubing can be used as protective tubing for precision instruments, electronic components, etc., as well as for fluid guiding hoses, medical device insertion tubing for guide wires, etc., and as assembly fixtures for fluid guiding hoses, etc. When not needed, the tubing can be removed by peeling.

[0003] Currently, the main material for easy-peel tubing on the market is PTFE, which is expensive and primarily manufactured overseas due to its complex production process and high technical barriers. However, with the rapid development of the medical field, the demand for easy-peel tubing is increasing, but the long procurement cycle from overseas significantly impacts the development of the domestic medical industry. Our company has independently developed an easy-peel tubing made of polyolefin and its copolymer resins. Its tear strength is lower than that of PTFE easy-peel tubing, and it does not adhere to the internal materials, making it a complete replacement for PTFE easy-peel tubing and providing a new option for easy-peel tubing. Summary of the Invention

[0004] The main objective of this invention is to provide an easy-peel pipe made of polyolefin and its copolymer resins and reinforcing agents, which has a tear strength lower than that of PTFE easy-peel pipe, a higher tensile strength, and no adhesion to the internal material.

[0005] To achieve the above objectives, the present invention provides an easy-peeling pipe with linear tearability along its length. The easy-peeling pipe material comprises the following components by weight:

[0006] Ethylene-acrylate copolymer: 20-90 parts;

[0007] Enhancer: 10-80 parts.

[0008] In some embodiments of this application, the ethylene-acrylate copolymer includes at least one of ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA), and ethylene-methyl methacrylate copolymer (EMMA).

[0009] In some embodiments of this application, the reinforcing agent includes at least one of polyethylene (PE), polyolefin elastomer (POE), and ethylene-vinyl acetate copolymer (EVA).

[0010] In some embodiments of this application, the ethylene-acrylate copolymer has a melt index of (0.5-10) g / 10 min and an acrylic acid content of 9 wt%-30 wt%.

[0011] Alternatively, the tear strength of the ethylene-acrylate copolymer is less than 75 kN / m;

[0012] Alternatively, the ethylene-acrylate copolymer has a tensile strength of 15-24 MPa.

[0013] In some embodiments of this application, the polyethylene (PE) is low-density polyethylene (LDPE), the melt index of which is (0.3-7) g / 10min and the tensile strength is 17-30 MPa.

[0014] Alternatively, the polyethylene (PE) is linear low-density polyethylene (LLDPE), wherein the linear low-density polyethylene (LLDPE) has a melt index of (0.3-10) g / 10min and a tensile strength of 20-35 MPa;

[0015] Alternatively, the polyethylene (PE) is medium-density polyethylene (MDPE), the MDPE has a melt index of (0.3-10) g / 10min and a tensile strength of 25-35 MPa;

[0016] Alternatively, the polyethylene (PE) is high-density polyethylene (HDPE), with a melt index of (0.3-10) g / 10 min and a tensile strength of 28-40 MPa.

[0017] In some embodiments of this application, the polyolefin elastomer (POE) has a melt index of (0.5-5) g / 10 min, a tensile strength of 18-40 MPa, and a melt temperature of 70-110 °C.

[0018] In some embodiments of this application, the ethylene-vinyl acetate copolymer (EVA) has a melt index of (0.5-7) g / 10 min, a tensile strength of 16-25 MPa, and a vinyl acetate (VA) content of no more than 20%.

[0019] In some embodiments of this application, the easily peelable pipe material further includes the following additives by weight:

[0020] Antioxidant 0.05-0.3 parts;

[0021] Lubricant 0.05-0.1 parts;

[0022] The antioxidants include at least one of asymmetric hindered phenolic antioxidants, aromatic amine antioxidants, thioether antioxidants, and phosphite antioxidants.

[0023] The lubricant includes at least one of PTFE powder, zinc stearate, magnesium stearate, silicone, calcium stearate, or ethylene bis-stearamide.

[0024] To achieve the above objectives, the present invention also provides a method for preparing an easily peelable pipe, comprising the following steps:

[0025] Masterbatch processing: Ethylene-acrylate copolymer and reinforcing agent are mixed evenly according to the formula, and then extruded, drawn into strands and cut into pellets by extrusion equipment to obtain masterbatch pellets;

[0026] Extrusion into tubes: The masterbatch particles obtained above are extruded through an extruder to obtain the easily peelable tube, wherein the orientation degree of the molecular chain of the extruded tube is controlled to be 23%-95%.

[0027] In some embodiments of this application, during the masterbatch processing step, when the ethylene-acrylate copolymer and reinforcing agent are mixed, antioxidants and lubricants may also be added for mixing.

[0028] Alternatively, in the masterbatch processing step, the mixing time is 3-5 minutes;

[0029] Alternatively, in the masterbatch processing step, the extrusion temperature of the extrusion equipment is 130-200℃;

[0030] Alternatively, in the extrusion tube forming step, the orientation degree of the molecular chains of the extruded tube is 30%-90%.

[0031] The beneficial effects that this invention can achieve are:

[0032] This invention relates to an easily peelable pipe that uses ethylene-acrylate copolymer and a reinforcing agent as the matrix resin. Because ethylene-acrylate is a copolymer and contains acrylate side groups, its crystallization is disrupted, increasing the distance between the main chain vinyl molecules and reducing molecular entanglement. This reduces the cohesive strength of the ethylene-acrylate molecular chains. The addition of the reinforcing agent improves the tensile strength of the molecular structure. Furthermore, the orientation of the molecular chains within the ethylene-acrylate copolymer and reinforcing agent blend is controlled through the extrusion process, ensuring that the orientation is within a certain range. This allows the molecular chains and segments of the ethylene-acrylate copolymer and reinforcing agent blend to extend from a freely coiled, disordered state towards the oriented direction, reducing molecular entanglement while enhancing the tensile strength of the molecular structure. This achieves both tearability and improved tensile strength of the pipe. Detailed Implementation

[0033] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] In this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Furthermore, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0036] This invention provides an easy-peel pipe with linear tearability along its length. The material used to prepare the easy-peel pipe comprises the following components, calculated by weight:

[0037] Ethylene-acrylate copolymer: 20-90 parts;

[0038] Enhancer: 10-80 parts.

[0039] Ethylene-acrylate copolymers are copolymers of ethylene and acrylates, and mainly include ethylene-methyl acrylate copolymers (EMA), ethylene-ethyl acrylate copolymers (EEA), ethylene-butyl acrylate copolymers (EBA), and ethylene-methyl methacrylate copolymers (EMMA). The properties of ethylene-acrylate copolymers are related to the content, average molecular weight, molecular weight distribution, and length of the acrylate monomers.

[0040] The reinforcing agent includes at least one of polyethylene (PE), polyolefin elastomer (POE), and ethylene-vinyl acetate copolymer (EVA). Polyethylene is a thermoplastic plastic polymerized from ethylene. Due to the different densities of the resins obtained from different polymerization methods, it is classified into high-density polyethylene (HDPE), medium-density polyethylene (MDPE), linear low-density polyethylene (LLDPE), and low-density polyethylene (LDPE). Polyolefin elastomer (POE) can be one of the random copolymer elastomers of ethylene with 1-butene, ethylene with 1-hexene, ethylene with 1-octene, etc.; when using ethylene-vinyl acetate copolymer (EVA), a vinyl acetate (VA) content of less than 20% provides better reinforcing effect.

[0041] Polymer orientation refers to a structure in which molecular chains or other structural units are preferentially aligned and frozen along the direction of an external force. In melt-extruded ethylene-acrylate copolymers and reinforcing agent blends, the molecular chains align along the stretching direction after a stretching process, i.e., preferential orientation along the stretching direction.

[0042] Polymer materials exist in a state where the molecular chains constituting them are entangled like a ball of yarn. In molded bodies made from polymer materials, this entanglement of molecules is also maintained, and the physical properties of the molded body have a significant impact on the structure of this molecular entanglement. During our research on peelable pipes, we unexpectedly discovered that using ethylene-acrylate copolymers as the matrix resin, while ensuring that the orientation degree of the molecular chains in the extruded pipe is within the range of 23%-95% during the extrusion process, allows us to prepare easily peelable pipes with linear tearability along the length of the pipe. This may be due to the unique structure of substances like ethylene-acrylate copolymers. The presence of short branches such as methyl acrylate, ethyl acrylate, butyl acrylate, and methyl methacrylate disrupts their crystallization, increases the distance between the main chain vinyl molecules, reduces the cohesive strength of the ethylene-acrylate copolymer molecular chains, and decreases the molecular entanglement structure. The addition of reinforcing agents can improve the tensile strength of the molecular structure. Furthermore, by controlling the orientation degree of the molecular chains inside the ethylene-acrylate copolymer and reinforcing agent blend through the extrusion process, the orientation degree is kept within the range of 23%-95%. This allows the molecular chains and segments of the ethylene-acrylate copolymer and reinforcing agent blend to extend from a freely coiled, disordered state towards the orientation direction, reducing the linear entanglement structure of the blend molecules. Reinforcing agents possess high crystallinity or long-branched characteristics. Highly crystallinity reinforcing agents, such as PE or EVA, cause the crystals to transform from spherulites to monoclinic crystals during pipe extrusion stretching and orientation. The formation of monoclinic crystals not only increases the tensile strength in the orientation direction but also increases the number of physical crosslinking points formed by the blend's molecular chains and segments along the orientation direction (i.e., along the pipe's length), thus significantly improving the tensile strength in the pipe's orientation direction. Conversely, reinforcing agents containing long branches, such as POE or LDPE, can form certain physical crosslinking points with the crystalline regions of ethylene-acrylate copolymers. During extrusion stretching and orientation, the ethylene-acrylate copolymer is stretched from spherulites to monoclinic crystals, forming physical crosslinking points with the oriented long-branched molecules, increasing the strength in the orientation direction. However, the number of physical crosslinking points perpendicular to the orientation direction is significantly reduced, resulting in lower strength perpendicular to the orientation direction. By adding an appropriate proportion of reinforcing agent and controlling the orientation degree during the extrusion stretching process, the reinforcing agent forms fiber-like reinforcing units along the orientation direction when the ethylene-acrylate copolymer is oriented, further improving the pipe's tearability. Therefore, the addition of reinforcing agents can not only improve the tensile strength of the pipe in the orientation direction, but also further improve its tearability along the length of the pipe.

[0043] In the extrusion process, extruded pipes with different draw ratios are generally obtained by controlling the traction speed and extrusion speed of the extruded pipe. By controlling the draw ratio of the extruded pipe between 7 and 30, extruded pipes with molecular chain orientation of 23%-95% can be obtained.

[0044] When the content of acrylate monomers in ethylene-acrylate copolymers increases, the orderliness of their molecular chains decreases further, while the content of acrylic acid side groups also increases. This leads to decreased crystallinity, a lower melting point, and improved tearability. However, if the content of acrylate monomers is too high, the cohesive strength will be too low, resulting in problems such as reduced overall pipe strength, affecting the molding and use of the pipe. Therefore, an acrylic acid content of 9wt%-30wt% is preferable.

[0045] Melt index (MI) is an indicator of resin flowability. It is the mass (in grams) of molten resin passing through a standard capillary tube in 10 minutes at a given temperature and pressure, expressed in grams per 10 minutes. A high melt index indicates a low average molecular weight and low viscosity, resulting in good flowability and ease of processing and molding, but poorer mechanical properties. Conversely, a low melt index indicates a high average molecular weight and high viscosity, leading to poorer flowability and more difficult molding, but better mechanical properties. In some embodiments, the melt index (MI) of ethylene-acrylate copolymer is (0.5-10) g / 10min; a melt index within this range satisfies both good flowability and good mechanical properties.

[0046] In some embodiments, the ethylene-acrylate copolymer has a tear strength of less than 75 kN / m, which facilitates better removal of the pipe.

[0047] In some embodiments, the tensile strength of the ethylene-acrylate copolymer is 15-24 MPa, and tensile strength within this range can further improve the tensile strength of the pipe.

[0048] In some embodiments, the polyethylene (PE) is low-density polyethylene (LDPE), with a melt index of (0.3-7) g / 10 min and a tensile strength of 17-30 MPa.

[0049] In some embodiments, the polyethylene (PE) is linear low-density polyethylene (LLDPE), with a melt index of (0.3-10) g / 10 min and a tensile strength of 20-35 MPa.

[0050] In some embodiments, the polyethylene (PE) is medium-density polyethylene (MDPE), with a melt index of (0.3-10) g / 10 min and a tensile strength of 25-35 MPa.

[0051] In some embodiments, the polyethylene (PE) is high-density polyethylene (HDPE), with a melt index of (0.3-10) g / 10 min and a tensile strength of 28-40 MPa.

[0052] In some embodiments, the polyolefin elastomer (POE) has a melt index of (0.5-5) g / 10 min, a tensile strength of 18-40 MPa, and a melt temperature of 70-110 °C.

[0053] In some embodiments, the ethylene-vinyl acetate copolymer (EVA) has a melt index of (0.5-7) g / 10 min, a tensile strength of 16-25 MPa, and a vinyl acetate (VA) content of no more than 20%.

[0054] In some embodiments, the easy-peeling tubing material further includes the following additives:

[0055] Antioxidant 0.05-0.3 parts;

[0056] Lubricant 0.05-0.1 parts;

[0057] In some embodiments, the antioxidant includes at least one of asymmetric hindered phenolic antioxidants, aromatic amine antioxidants, thioether antioxidants, and phosphite antioxidants.

[0058] Hindered phenolic antioxidants include at least one of antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), BHT (2,6-di-tert-butyl-p-cresol), and antioxidant 1076 (octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate).

[0059] Aromatic amine antioxidants include diphenylamine, p-phenylenediamine, and dihydroquinoline and their derivatives or polymers, such as antioxidant 445 (4,4'-bis(α.α-dimethylbenzyl)diphenylamine).

[0060] Thioether antioxidants include at least one of DLTP (dilauryl thiodipropionate), DSTDP (thiodipropionate distearate), and DSTP (octadecyl thiodipropionate).

[0061] Phosphite antioxidants include at least one of antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite), antioxidant 618 (pentaerythritol diphosphite bis(octadecyl)ester), and antioxidant 626 (bis[2,4-di-tert-butylphenyl]pentaerythritol diphosphite).

[0062] Adding antioxidants improves the antioxidant and aging resistance of easy-peel pipes, thus extending their service life.

[0063] In some embodiments, the lubricant includes at least one of PTFE powder, zinc stearate, magnesium stearate, silicone, calcium stearate, or ethylene bis-stearamide. Adding a lubricant helps to promote more uniform mixing of the various raw materials.

[0064] In some embodiments, the easy-peeling pipe material comprises the following components, by weight:

[0065] Ethylene-acrylate copolymer: 20-90 parts; reinforcing agent: 10-80 parts. For example, the ethylene-acrylate copolymer can be any one part by weight in the range of 20-90 parts, such as 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, or 90 parts; the reinforcing agent can be any one part by weight in the range of 10-80 parts, such as 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, or 80 parts.

[0066] Under the above-mentioned weight limits, it is beneficial to promote the mixing of various raw materials, which can satisfy both the linear tear performance and achieve a certain tensile strength.

[0067] This invention also provides a method for preparing an easily peelable pipe, comprising the following steps:

[0068] Masterbatch processing: Ethylene-acrylate copolymer and reinforcing agent are mixed evenly according to the formula, and then extruded, drawn into strands and cut into pellets by extrusion equipment to obtain masterbatch pellets;

[0069] Extrusion into pipe: The masterbatch particles obtained above are extruded into pipes through an extruder to obtain the easily peelable pipes, wherein the orientation degree of the molecular chains of the extruded pipes is controlled to be 23%-95%.

[0070] In some embodiments, during the masterbatch processing step, when mixing the ethylene-acrylate copolymer and the reinforcing agent, antioxidants and lubricants may also be added for mixing.

[0071] In some embodiments, the mixing time in the masterbatch processing step is 3-5 minutes.

[0072] In some embodiments, during the masterbatch processing step, the extrusion temperature of the extrusion equipment is 130-200°C.

[0073] In some embodiments, during the extrusion tube forming step, the orientation degree of the molecular chains of the extruded tube is 30%-90%.

[0074] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0075] Orientation determination

[0076] A single-screw extruder is used, with the following die specifications: die diameter D1 (mm), mandrel diameter D2 (mm). The dimensions of the extruded tube are as follows: inner diameter d1 (mm), wall thickness w (mm). (Depending on the tube dimensions, the appropriate extruder, die, and mandrel model must be selected.) During the extrusion process, we control the traction speed and extrusion speed to obtain extruded tubes with different draw ratios. The draw ratio calculation formula is as follows:

[0077]

[0078] The orientation degree of the molecular chains in the extruded tube was studied by X-ray diffraction (D / Max-rA type rotating target X-ray diffractometer), and the orientation degree was calculated using the following formula:

[0079]

[0080] П represents the orientation degree, and H represents the angle of the equatorial diffraction distribution along one diffraction arc of the Debye ring. During measurement, the half-width of the intensity distribution, i.e., half of the maximum intensity on the arc segment, is used as the start and end points of the arc segment.

[0081] Test of tearing linearity

[0082] To more clearly determine tear linearity, the following method was used for measurement. A 40mm incision was made at one end of a 1000mm long sample. The incision was made parallel to the length of the tube at the center using a clamp. The tube was torn from the incision at a speed of 200mm / min to the other end. The weights of the two torn sections were measured, and the weight ratio was determined. It was determined that the closer the ratio was to 50%:50%, the higher the tear linearity.

[0083] Tear strength test

[0084] After making a 40mm incision with a knife, take a 100mm sample and tear it using a tensile testing machine at a speed of 200mm / min. Measure the maximum force at that moment as the tear strength. Perform three measurements on samples with the same composition and calculate the weighted average.

[0085] Tensile strength test

[0086] The test was conducted in accordance with the method in UL 224-2021, 5.4.

[0087] Example 1

[0088] Masterbatch processing

[0089] Ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1, added to a high-speed mixer and stirred for 3-5 minutes. The material obtained from the above process is fed into a 30mm diameter twin-screw extruder, extruded at a screw speed of 45rpm and a temperature of 130-200℃, stretched, water-cooled and pelletized to finally form masterbatch granules.

[0090] Extruded pipes

[0091] The masterbatch granules obtained above were used to form tubes using a single-screw extruder. A fully threaded screw was used, with a screw speed of 5-45 rpm and a die temperature of 130-190℃, controlling the molecular chain orientation of the extruded tube to be within 50%. Tubes with an inner diameter of 0.5 mm, an outer diameter of 0.9 mm, and a wall thickness of 0.2 mm were obtained.

[0092] Example 2

[0093] Masterbatch processing

[0094] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-ethyl acrylate copolymer (EEA, ELVALOY) TM Except for the ratio of AC 2116) / low-density polyethylene (LDPE, lyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0095] Extruded pipes

[0096] The molding process was carried out in the same manner as in Example 1.

[0097] Example 3

[0098] Masterbatch processing

[0099] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM The mixture of AC 1218) / low-density polyethylene (LDPE, lyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 was replaced with ethylene-butyl acrylate copolymer (EBA, AC 3717) / low-density polyethylene (LDPE, lyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1, and was manufactured in the same manner as in Example 1.

[0100] Extruded pipes

[0101] The molding process was carried out in the same manner as in Example 1.

[0102] Example 4

[0103] Masterbatch processing

[0104] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM The mixture of AC 1218) / low-density polyethylene (LDPE, lyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 was replaced with ethylene-methyl methacrylate copolymer (EMMA, Sumitomo CM8014) / low-density polyethylene (LDPE, lyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1, and was manufactured in the same manner as in Example 1.

[0105] Extruded pipes

[0106] The molding process was carried out in the same manner as in Example 1.

[0107] Example 5

[0108] Masterbatch processing

[0109] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Linear low-density polyethylene (LLDPE) Except that the ratio of LLDPE 218W / antioxidant (antioxidant 1010) (mass ratio) was 60 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0110] Extruded pipes

[0111] The molding process was carried out in the same manner as in Example 1.

[0112] Example 6

[0113] Masterbatch processing

[0114] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Medium density polyethylene (MDPE, DOWAXELERON) TM Except for the ratio of 8864NT) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0115] Extruded pipes

[0116] The molding process was carried out in the same manner as in Example 1.

[0117] Example 7

[0118] Masterbatch processing

[0119] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for the ratio of AC 1218 / high-density polyethylene (HDPE, Lyondellbasell ACP 6541A) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0120] Extruded pipes

[0121] The molding process was carried out in the same manner as in Example 1.

[0122] Example 8

[0123] Masterbatch processing

[0124] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Polyolefin elastomer (POE, ENGAGE) TM Except for the ratio of 8480) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0125] Extruded pipes

[0126] The molding process was carried out in the same manner as in Example 1.

[0127] Example 9

[0128] Masterbatch processing

[0129] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for the mass ratio of AC 1218) / ethylene-vinyl acetate copolymer (EVA, 7350M) / antioxidant (antioxidant 1010) (60 / 10 / 0.1), it was manufactured in the same manner as in Example 1.

[0130] Extruded pipes

[0131] The molding process was carried out in the same manner as in Example 1.

[0132] Example 10

[0133] Masterbatch processing

[0134] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, Lyondellbasell Lupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TMExcept for the ratio of AC 1218) / low-density polyethylene (LDPE, Lyondellbasell Lupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 20 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0135] Extruded pipes

[0136] The molding process was carried out in the same manner as in Example 1.

[0137] Example 11

[0138] Masterbatch processing

[0139] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for AC 1218) / low-density polyethylene (LDPE, lyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) = 75 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0140] Extruded pipes

[0141] The molding process was carried out in the same manner as in Example 1.

[0142] Example 12

[0143] Masterbatch processing

[0144] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for the ratio of AC 1218) / low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 90 / 10 / 0.1, it was manufactured in the same manner as in Example 1.

[0145] Extruded pipes

[0146] The molding process was carried out in the same manner as in Example 1.

[0147] Example 13

[0148] Masterbatch processing

[0149] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for the mass ratio of AC 1218) / low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (60 / 40 / 0.1), it was manufactured in the same manner as in Example 1.

[0150] Extruded pipes

[0151] The molding process was carried out in the same manner as in Example 1.

[0152] Example 14

[0153] Masterbatch processing

[0154] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for the mass ratio of AC 1218) / low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (60 / 60 / 0.1), it was manufactured in the same manner as in Example 1.

[0155] Extruded pipes

[0156] The molding process was carried out in the same manner as in Example 1.

[0157] Example 15

[0158] Masterbatch processing

[0159] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TMAC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for the mass ratio of AC 1218) / low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (60 / 80 / 0.1), it was manufactured in the same manner as in Example 1.

[0160] Extruded pipes

[0161] The molding process was carried out in the same manner as in Example 1.

[0162] Example 16

[0163] Masterbatch processing

[0164] It was manufactured in the same manner as in Example 1.

[0165] Extruded pipes

[0166] Except for controlling the orientation degree to 23%, the molding process was carried out in the same manner as in Example 1.

[0167] Example 17

[0168] Masterbatch processing

[0169] It was manufactured in the same manner as in Example 1.

[0170] Extruded pipes

[0171] Except for controlling the orientation degree to 30%, the molding process was carried out in the same manner as in Example 1.

[0172] Example 18

[0173] Masterbatch processing

[0174] It was manufactured in the same manner as in Example 1.

[0175] Extruded pipes

[0176] Except for controlling the orientation degree to be 90%, the molding process was carried out in the same manner as in Example 1.

[0177] Example 19

[0178] Masterbatch processing

[0179] It was manufactured in the same manner as in Example 1.

[0180] Extruded pipes

[0181] Except for controlling the orientation degree to 95%, the molding process was carried out in the same manner as in Example 1.

[0182] Comparative Example 1

[0183] Masterbatch processing

[0184] Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 0.1 is added to a high-speed mixer and stirred for 3-5 minutes. The material obtained in the above process is fed into a twin-screw extruder with a cylinder diameter of 30mm, and extruded at a screw speed of 45rpm and a die temperature of 130-200℃. The material is then stretched, water-cooled, and pelletized to finally form masterbatch granules.

[0185] Extruded pipes

[0186] The masterbatch granules obtained above were used to form tubes using a single-screw extruder. A fully threaded screw was used, with a screw speed of 10-30 rpm and a die temperature of 130-190℃, controlling the molecular chain orientation of the extruded tube to be within 50%. Tubes with an inner diameter of 0.5 mm, an outer diameter of 0.9 mm, and a wall thickness of 0.2 mm were obtained.

[0187] Comparative Example 2

[0188] Masterbatch processing

[0189] Except for replacing the low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 0.1 with polyolefin elastomer (POE, ENGINEER). TM Except for the ratio of 8480) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 0.1, it was manufactured in the same manner as Comparative Example 1.

[0190] Extruded pipes

[0191] The molding process was carried out in the same manner as Comparative Example 1.

[0192] Comparative Example 3

[0193] Masterbatch processing

[0194] The same process as Comparative Example 1 was performed, except that the ratio of low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 0.1 was replaced with ethylene-vinyl acetate copolymer (EVA, 7350M) / antioxidant (antioxidant 1010) (mass ratio) = 60 / 0.1.

[0195] Extruded pipes

[0196] The molding process was carried out in the same manner as Comparative Example 1.

[0197] Comparative Example 4

[0198] Masterbatch processing

[0199] In addition to ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM AC 1218) / Low-density polyethylene (LDPE, LyondellbasellLupolen 2426K) / Antioxidant (Antioxidant 1010) (mass ratio) = 60 / 10 / 0.1 Replace with ethylene-methyl acrylate copolymer (EMA, DuPont ELVALOY) TM Except for the ratio of AC 1218 (to antioxidant 1010) (by mass) = 60 / 0.1, it was manufactured in the same manner as in Example 1.

[0200] Extruded pipes

[0201] The molding process was carried out in the same manner as in Example 1.

[0202] Comparative Example 5

[0203] Masterbatch processing

[0204] It was manufactured in the same manner as in Example 1.

[0205] Extruded pipes

[0206] Except for controlling the orientation degree to 15%, the molding process was carried out in the same manner as in Example 1.

[0207] Comparative Example 6

[0208] It uses commercially available PTFE tear-resistant sheath, specification AWG 24F.

[0209] For the easily peelable tubes prepared above, the preparation conditions for Examples 1-19 are shown in Table 1, and the preparation conditions for Comparative Examples 1-6 are shown in Table 2. The orientation degree of the extruded tube molecular chains was controlled during the extrusion process according to the above-described orientation degree determination method; the orientation degree of the commercially available PTFE tearable sheath in Comparative Example 6 was measured; the tear linearity was measured according to the above-described tear strength test method; the tear strength was measured according to the above-described tensile strength test method; and the tensile strength was measured according to the above-described tensile strength test method. The measurement results for Examples 1-19 and Comparative Examples 1-6 are shown in Table 3.

[0210] Table 1. Preparation conditions and parameters for Examples 1-19

[0211]

[0212]

[0213] Table 2 Preparation conditions for Comparative Examples 1-6

[0214]

[0215] Table 3. Measurement results of Examples 1-19 and Comparative Examples 1-6

[0216] Is it tearable? Tearing straight Tear strength (N) Tensile strength (MPa) Example 1 Y 50:50 8.3 17.5 Example 2 Y 50:50 8.5 17.8 Example 3 Y 50:50 9.0 18.5 Example 4 Y 50:50 8.3 17.5 Example 5 Y 50:50 9.0 19.5 Example 6 Y 50:50 10.5 21.5 Example 7 Y 50:50 11 23.5 Example 8 Y 50:50 10 20.5 Example 9 Y 50:50 9.0 19.5 Example 10 Y 50:50 9.2 19.0 Example 11 Y 50:50 8.0 17.0 Example 12 Y 50:50 8.0 16.5 Example 13 Y 50:50 9.2 19.5 Example 14 Y 50:50 9.3 20.0 Example 15 Y 50:50 9.5 20.0 Example 16 Y 48:52 9.0 17.0 Example 17 Y 49:51 9.0 17.0 Example 18 Y 50:50 8.0 17.5 Example 19 Y 50:50 8.0 17.5 Comparative Example 1 N / / 21 Comparative Example 2 N / / 24 Comparative Example 3 N / / 19 Comparative Example 4 Y 50:50 8.5 16 Comparative Example 5 N / / 17.5 Comparative Example 6 Y 50:50 12 45

[0217] Examples 1-4 and Comparative Examples 1-3 show that the type of polymer is highly dependent on the type of easy-peel pipe made from polyolefin and its copolymer resins; only specific ethylene-acrylate copolymers can be used to prepare easy-peel pipes. Examples 1, 16-19 and Comparative Example 5 show that, in addition to the type of polymer, the molecular chain orientation of the extruded pipe must be controlled to 23%-95% during the extrusion process to produce a pipe with linear tear resistance. Examples 1 and Comparative Example 4 show that the addition of a reinforcing agent can increase the tensile strength of the easy-peel pipe. This invention provides an easy-peel pipe made from polyolefin and its copolymer resins and a reinforcing agent, which has lower tear strength than PTFE easy-peel pipes, higher tensile strength, and no adhesion to the internal material, making it a complete replacement for PTFE easy-peel pipes and providing a new option for easy-peel pipes.

[0218] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. An easily peelable pipe, characterized in that it has linear tearability along its length, wherein... The easy-peeling pipe material comprises the following components in parts by weight: Ethylene-acrylate copolymer: 20-90 parts; Enhancer: 10-80 parts.

2. The easily peelable pipe according to claim 1, characterized in that, The ethylene-acrylate copolymer includes at least one of ethylene-methyl acrylate copolymer (EMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-butyl acrylate copolymer (EBA), and ethylene-methyl methacrylate copolymer (EMMA).

3. The easily peelable pipe according to claim 1, characterized in that, The reinforcing agent includes at least one of polyethylene (PE), polyolefin elastomer (POE), and ethylene-vinyl acetate copolymer (EVA).

4. The easily peelable pipe according to claim 1, characterized in that, The ethylene-acrylate copolymer has a melt index of (0.5-10) g / 10 min and an acrylic acid content of 9wt%-30wt%. Alternatively, the tear strength of the ethylene-acrylate copolymer is less than 75 kN / m; Alternatively, the ethylene-acrylate copolymer has a tensile strength of 15-24 MPa.

5. The easily peelable pipe according to claim 3, characterized in that, The polyethylene (PE) is low-density polyethylene (LDPE), and the low-density polyethylene (LDPE) has a melt index of (0.3-7) g / 10min and a tensile strength of 17-30 MPa. Alternatively, the polyethylene (PE) is linear low-density polyethylene (LLDPE), wherein the linear low-density polyethylene (LLDPE) has a melt index of (0.3-10) g / 10min and a tensile strength of 20-35 MPa; Alternatively, the polyethylene (PE) is medium-density polyethylene (MDPE), the MDPE has a melt index of (0.3-10) g / 10min and a tensile strength of 25-35 MPa; Alternatively, the polyethylene (PE) is high-density polyethylene (HDPE), with a melt index of (0.3-10) g / 10 min and a tensile strength of 28-40 MPa.

6. The easily peelable pipe according to claim 3, characterized in that, The polyolefin elastomer (POE) has a melt index of (0.5-5) g / 10 min, a tensile strength of 18-40 MPa, and a melting temperature of 70-110℃.

7. The easily peelable pipe according to claim 3, characterized in that, The ethylene-vinyl acetate copolymer (EVA) has a melt index of (0.5-7) g / 10min, a tensile strength of 16-25 MPa, and a vinyl acetate (VA) content of no more than 20%.

8. The easily peelable pipe according to claim 1, characterized in that, Based on parts by weight, the easy-peel pipe preparation material also includes the following additives: Antioxidant 0.05-0.3 parts; Lubricant 0.05-0.1 parts; The antioxidants include at least one of asymmetric hindered phenolic antioxidants, aromatic amine antioxidants, thioether antioxidants, and phosphite antioxidants. The lubricant includes at least one of PTFE powder, zinc stearate, magnesium stearate, silicone, calcium stearate, or ethylene bis-stearamide.

9. A method for preparing an easily peelable pipe, characterized in that, Includes the following steps: Masterbatch processing: Ethylene-acrylate copolymer and reinforcing agent are mixed evenly according to the formula, and then extruded, drawn into strands and cut into pellets by extrusion equipment to obtain masterbatch pellets; Extrusion into pipe: The masterbatch particles obtained above are extruded into pipes through an extruder to obtain the easily peelable pipes, wherein the orientation degree of the molecular chains of the extruded pipes is controlled to be 23%-95%.

10. The preparation method according to claim 9, characterized in that, In the masterbatch processing step, when the ethylene-acrylate copolymer and reinforcing agent are mixed, antioxidants and lubricants may also be added for mixing. Alternatively, in the masterbatch processing step, the mixing time is 3-5 minutes; Alternatively, in the masterbatch processing step, the extrusion temperature of the extrusion equipment is 130-200℃; Alternatively, in the extrusion tube forming step, the orientation degree of the molecular chains of the extruded tube is 30%-90%.

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