Heat shrink tube and preparation method thereof

Abstract

The invention discloses a heat shrink tube. The heat shrink tube comprises chlorosulfonated polyethylene and a polyester elastomer which are used as matrix resin. Chlorosulfonated polyethylene has good oil resistance and high temperature aging resistance, and because the chlorosulfonated polyethylene contains chlorine atoms in the structure, the chlorosulfonated polyethylene itself has a certain flame retardant property, but has the problems of poor cold resistance, easy hardening and embrittlement at low temperature, obvious reduction of mechanical properties and the like. The polyester elastomer and chlorosulfonated polyethylene are added, so that the material has shrinkage internal stress after being expanded and shaped, the heat shrinkage characteristic is achieved, meanwhile, the polyester elastomer and chlorosulfonated polyethylene form an interpenetrating network structure, and the high-temperature resistance and low-temperature resistance of the heat-shrinkable tube are improved. According to the heat shrink tube, oil resistance, high temperature resistance, low temperature resistance and flame retardance of the heat shrink tube can be achieved at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of pipes, and in particular to a heat shrinkable tube. Background Art

[0002] With the development of heat shrink technology, heat shrink materials used in the fields of ships, locomotives, aviation, etc. are mainly traditional polyolefins and fluorine materials. Chlorosulfonated polyethylene sleeves are used as supplements to the former two, and their performance is between polyolefins and fluorine materials. Among them, polyolefins, especially amorphous polyolefin materials EVA and PE crystalline materials, have the advantage of amorphous polyolefin materials EVA is that the material is soft and can be filled with a large amount of flame retardants. The material still has good softness and processability, but this type of material does not have advantages in oil resistance and high temperature resistance; PE crystalline materials have their oil resistance and high temperature resistance decreased due to the large amount of flame retardants added to destroy their crystallinity.

[0003] Although fluorine materials have excellent oil resistance, solvent resistance and high temperature resistance, their high price, low temperature resistance and poor flexibility have greatly limited their widespread application.

[0004] In view of the above problems, it is urgent to develop an oil-resistant, high-temperature-resistant, low-temperature-resistant, flame-retardant heat shrinkable tube. Summary of the invention

[0005] The main purpose of the present invention is to provide an oil-resistant, high-temperature-resistant, low-temperature-resistant, flame-retardant heat shrinkable tube, which mainly solves the problems that the existing amorphous polyolefin material EVA and PE crystalline material heat shrinkable tubes have poor oil resistance and high-temperature resistance, and the heat shrinkable tubes made of fluorine materials have poor low-temperature resistance.

[0006] The above object of the present invention is achieved through the following technical solutions:

[0007] In a first aspect of the present invention, a heat shrinkable tube is provided, wherein the heat shrinkable tube preparation material comprises the following raw materials in parts by weight:

[0008] 100 parts of chlorosulfonated polyethylene, the chlorosulfonated polyethylene Mooney viscosity (ML 1+4100°C) is 50-80, and the degree of chlorination is 35-45%; 10-30 parts of polyester elastomer, the melt index of the polyester elastomer is 3-15g / 10min; 5-20 parts of chlorinated paraffin, the degree of chlorination of the chlorinated paraffin is 45-55%; 10-30 parts of flame retardant, the flame retardant is a metal hydroxide that has been passivated; 2-5 parts of plasticizer, the plasticizer is dioctyl phthalate, dioctyl adipate, dioctyl sebacate, dioctyl phthalate The invention discloses a novel cross-linking sensitizer, wherein the cross-linking sensitizer comprises at least one of trimethylallyl isocyanate and its derivatives, triallyl cyanurate and its derivatives, tripropargyl cyanurate and its derivatives, trimethylolpropane trimethacrylate and its derivatives, and trimethylolpropane triacrylate and its derivatives.

[0009] In a second aspect of the present invention, a method for preparing the above-mentioned heat shrinkable tube is provided, which comprises the following steps:

[0010] Masterbatch processing: adding the prepared materials of the heat shrink tube into an internal mixer, controlling the material temperature at 160±10°C, mixing for 5 to 10 minutes, and then forcibly feeding the mixture through a twin-screw extruder at a temperature of 160 to 200°C, extruding, drawing, and pelletizing to obtain masterbatch particles;

[0011] Extrusion into pipe: The masterbatch particles obtained above are extruded into pipes at a temperature of 150-200° C. through an extrusion device to obtain semi-finished pipes;

[0012] Irradiation process: irradiate the semi-finished pipes through irradiation equipment, control the irradiation dose to 5-10 Mrad, and obtain irradiated pipes;

[0013] Expansion molding: the irradiated tube is expanded, cooled, and formed to obtain a finished heat shrink tube.

[0014] The heat shrinkable tube of the present invention includes chlorosulfonated polyethylene and polyester elastomer as base resins. Chlorosulfonated polyethylene has good oil resistance and high temperature aging resistance, and because it contains chlorine atoms in its structure, it has certain flame retardant properties. However, it has poor cold resistance, is easy to harden and become brittle at low temperatures, and has obvious mechanical property degradation. The polyester elastomer is used as a heat shrinkable skeleton, which can make the material have shrinkage internal stress after expansion and shaping, and realize heat shrinkage characteristics. At the same time, the polyester elastomer and chlorosulfonated polyethylene form an interpenetrating network structure, which improves the high temperature resistance and low temperature resistance of the heat shrinkable tube. The heat shrinkable tube of the present invention can simultaneously realize the oil resistance, high temperature resistance, low temperature resistance, and flame retardant properties of the heat shrinkable tube. DETAILED DESCRIPTION

[0015] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0016] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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 creative work are within the scope of protection of the present invention.

[0017] In the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0018] With the development of heat shrink technology, heat shrink materials used in the fields of ships, locomotives, aviation, etc. are mainly traditional polyolefins and fluorine materials. Chlorosulfonated polyethylene casings are used as supplements to the former two, and their performance is between polyolefins and fluorine materials. Among them, polyolefins, especially EVA and PE, are not resistant to oil and high temperature. Although fluorine materials have excellent oil resistance, solvent resistance, and high temperature resistance, their high price, low temperature resistance, and poor flexibility have greatly limited their wide application.

[0019] Based on this, the first aspect of the present invention provides a heat shrinkable tube, wherein the heat shrinkable tube preparation material includes the following raw materials in parts by weight:

[0020] Chlorosulfonated polyethylene: 100 parts;

[0021] Polyester elastomer: 10-30 parts.

[0022] The polyester elastomer may be 10 parts by mass, 12 parts by mass, 14 parts by mass, 16 parts by mass, 18 parts by mass, 20 parts by mass, 22 parts by mass, 24 parts by mass, 26 parts by mass, 28 parts by mass or 30 parts by mass.

[0023] Chlorosulfonated polyethylene is a chlorine-containing special elastomer material with a highly saturated chemical structure obtained by chlorination and chlorosulfonation of polyethylene as the main raw material. Due to the presence of chlorosulfonyl active groups in the molecular structure, it exhibits high activity, good oil resistance and high temperature aging resistance, and due to the presence of chlorine atoms in its structure, it has certain flame retardant properties, but has poor cold resistance and obvious performance degradation at low temperatures. Thermoplastic polyester elastomer (TPEE) is a linear block copolymer containing polybutylene terephthalate (PBT) polyester hard segment and aliphatic polyester or polyether soft segment. Polyester elastomer is used as a heat shrink skeleton, which can make the material have shrinkage internal stress after expansion and finalization, and realize heat shrinkage characteristics. At the same time, polyester elastomer and chlorosulfonated polyethylene form an interpenetrating network structure, which improves the high temperature resistance and low temperature resistance of the heat shrinkable tube. The heat shrinkable tube of the present invention adopts chlorosulfonated polyethylene and polyester elastomer as the matrix resin, so that the prepared heat shrinkable tube has the characteristics of oil resistance, high temperature resistance, low temperature resistance, flame retardancy, etc.

[0024] In some embodiments, the Mooney viscosity (ML 1+4 100℃) is 50 to 80. High Mooney viscosity has higher tensile strength, better oil resistance and aging resistance, and can ensure dimensional stability of the extrusion process.

[0025] In some embodiments, the chlorination degree of the chlorosulfonated polyethylene is 35-45%. Controlling the chlorination degree of the chlorosulfonated polyethylene to 35-45% can ensure that the heat shrinkable tube has a certain low temperature resistance and a certain flame retardant performance.

[0026] In some embodiments, the melt index of the polyester elastomer is 3 to 15 g / 10 min. The melt index of the polyester elastomer is controlled to be 3 to 15 g / 10 min, which has excellent processing performance and good mechanical properties.

[0027] In some embodiments, the heat shrink tube preparation material further includes the following raw materials by weight: 5 to 20 parts of chlorinated paraffin. The addition of chlorinated paraffin can improve the flame retardant properties, low temperature properties, tensile strength and elongation retention rate after heat aging of the heat shrink tube.

[0028] In some embodiments, the degree of chlorination of the chlorinated paraffin is 45-55%. If the degree of chlorination is too low, the flame retardant performance is not significant; if the degree of chlorination is too high, although the flame retardant performance is improved, the low temperature performance is deteriorated.

[0029] In some embodiments, the heat shrink tube preparation material further includes the following raw materials in parts by weight: 10 to 30 parts of a flame retardant; the flame retardant is a metal hydroxide that has been passivated.

[0030] Metal hydroxides, such as aluminum hydroxide (Al(OH)3) and magnesium hydroxide (Mg(OH)2), have received extensive attention in the research and application of flame retardant materials due to their halogen-free and non-toxic environmentally friendly properties. These hydroxides will decompose and release crystal water when heated, absorbing a large amount of heat, thereby reducing the temperature of the polymer material, and the formed metal oxides can form a carbonized film on the surface of the material, isolating oxygen and heat, and effectively inhibiting further combustion of the material.

[0031] The passivation of metal hydroxides is a surface treatment technology that improves the corrosion resistance, wear resistance, surface hardness and electrical properties of metals by forming a protective film on the metal surface. This protective film is usually composed of metal oxides, hydroxides or salts, which can prevent direct contact between metals and corrosive media, thereby slowing down or stopping the corrosion process.

[0032] Passivation can be achieved by a variety of methods, including chemical passivation, electrochemical passivation, physical passivation, and heat treatment passivation. Chemical passivation is the reaction of metal and chemical solution to form a protective film on the surface, while electrochemical passivation uses the principle of electrolysis to generate an oxide film on the metal surface. Physical passivation may involve mechanical methods such as sandblasting or polishing, while heat treatment passivation is to heat the metal to form a dense oxide film. Passivation treatment is a prior art and is not limited here.

[0033] Specifically, the specific passivation treatment steps of the passivated aluminum hydroxide are as follows: disperse aluminum hydroxide and boric acid in a mass ratio of 100:(2-15) in an alcohol solution, stir and ultrasonically disperse for 20-40 minutes, then distill and recover the alcohol solution to leave loose modified aluminum hydroxide powder.

[0034] It is understandable that when metal hydroxide is used as a flame retardant, it is usually necessary to add more than 40wt% to have a flame retardant effect. A high filling amount will affect the mechanical properties of the material. In some cases, metal hydroxide may catalyze chlorinated paraffin, resulting in a dehydrochlorination reaction of chlorinated paraffin, thereby reducing the flame retardant properties of chlorinated paraffin. In order to solve this problem, the hydroxide can be passivated so that it does not catalyze chlorinated paraffin. The passivated metal hydroxide is used together with chlorinated paraffin as a flame retardant, and the smoke suppression of the metal hydroxide and the high-efficiency flame retardancy of chlorinated paraffin are used to produce a synergistic effect. This can not only reduce the amount of metal hydroxide added, improve the flame retardant properties of the heat shrinkable tube, but also improve the mechanical properties of the heat shrinkable tube.

[0035] In some embodiments, the heat shrink tube preparation material further includes the following raw materials in parts by weight: 10 to 30 parts of a flame retardant; the flame retardant is a metal hydroxide.

[0036] In some embodiments, the heat shrink tube preparation material also includes the following raw materials by weight: 2 to 5 parts of plasticizer, wherein the plasticizer is at least one of dioctyl phthalate, dioctyl adipate, dioctyl sebacate, and dibutyl phthalate. Plasticizer is a high boiling point, low volatility substance, and its molecular structure has a polar part and a non-polar part. Plasticizer molecules can be inserted between polymer molecular chains, weaken the intermolecular forces, increase the distance and activity space between polymer molecular chains, increase the plasticity of polymers, and reduce the processing temperature of polymers.

[0037] In some embodiments, the heat shrink tube preparation material further includes the following raw materials by weight: 0.2 to 2 parts of a cross-linking sensitizer, wherein the cross-linking sensitizer is at least one of trimethylallyl isocyanate and its derivatives, triallyl cyanurate and its derivatives, tripropargyl cyanurate and its derivatives, trimethylolpropane trimethacrylate and its derivatives, trimethylolpropane triacrylate and its derivatives.

[0038] In some embodiments, the heat shrink tube preparation material further includes the following raw materials by weight: 10-30 parts of a reinforcing agent, the reinforcing agent including at least one of diatomaceous earth, white carbon black, carbon black, kaolin, and talcum powder. The reinforcing agent can improve the tear strength of the heat shrink tube and increase the rigidity and hardness of the heat shrink tube.

[0039] In a second aspect of the present invention, a method for preparing the above-mentioned heat shrinkable tube is provided, which comprises the following steps:

[0040] Masterbatch processing: Chlorosulfonated polyethylene and polyester elastomer are mixed evenly, extruded, drawn and pelletized by extrusion equipment to obtain masterbatch particles;

[0041] Extrusion into pipe: Extruding the masterbatch particles obtained above into pipes through an extrusion device to obtain semi-finished pipes;

[0042] Irradiation process: irradiate the semi-finished pipes through irradiation equipment, control the irradiation dose to 5-10 Mrad, and obtain irradiated pipes;

[0043] Expansion molding: the irradiated tube is expanded, cooled, and formed to obtain a finished heat shrink tube.

[0044] It is understandable that in the masterbatch processing step, chlorosulfonated polyethylene and polyester elastomer can be added to an internal mixer, the material temperature is controlled at 160±10°C, and mixed for 5 to 10 minutes to make them uniformly mixed. Then, through an extrusion device such as a twin-screw extruder or a single-screw extruder, extrusion, stranding, cooling, and pelletizing are obtained to obtain masterbatch particles.

[0045] It can be understood that in the extrusion tube step, the above-mentioned masterbatch particles after pelletizing are dried at 60-80°C for 3-5 hours using a dryer, and the dried masterbatch particles are passed through an extrusion device, such as a twin-screw extruder or a single-screw extruder, to extrude the semi-finished tube at a temperature of 150-200°C.

[0046] It can be understood that in the irradiation step, the semi-finished pipe is passed through an irradiation device, such as an electron accelerator irradiation device or a radioactive isotope irradiation device, and the irradiation dose is controlled to be 5-10 Mrad to obtain an irradiated pipe.

[0047] It can be understood that in the expansion molding step, the irradiated tube is expanded at a temperature of 150-180° C. by an expander, and then cooled and shaped to obtain a finished heat shrink tube.

[0048] In some embodiments of the present application, in the masterbatch processing step, when the chlorosulfonated polyethylene and the polyester elastomer are mixed, at least one of chlorinated paraffin, a flame retardant, a plasticizer, a cross-linking sensitizer, and a reinforcing agent is also added for mixing;

[0049] Or, in the extrusion tube forming step, the extrusion temperature of the extrusion equipment is 150-200°C;

[0050] Alternatively, in the expansion molding step, the expansion temperature is 150-180°C.

[0051] The present invention is further described in detail below with reference to specific embodiments.

[0052] The information of the raw materials involved in the specific implementation is shown in Table 1:

[0053] Table 1 Information of raw materials of Examples and Comparative Examples

[0054]

[0055]

[0056] Example 1

[0057] Please refer to Table 1 and Table 2. The heat shrink tube of this embodiment includes the following raw materials in parts by weight:

[0058] Chlorosulfonated polyethylene 1:100 parts;

[0059] Polyester elastomer: 10 parts;

[0060] Chlorinated paraffin 1: 12 parts;

[0061] Passivated Al(OH)3: 20 parts;

[0062] Dioctyl phthalate: 3.5 parts

[0063] Trimethylallyl isocyanate: 0.6 parts;

[0064] White carbon black: 20 parts.

[0065] The preparation method of the heat shrinkable tube is as follows:

[0066] Masterbatch processing: first, chlorosulfonated polyethylene 1, polyester elastomer, chlorinated paraffin 1, passivated Al(OH)3, dioctyl phthalate, trimethylallyl isocyanate, and white carbon black are added to an internal mixer, the material temperature is controlled at 160±10°C, and mixed for 5 to 10 minutes, and then the mixture is forced to be fed through a twin-screw extruder at a temperature of 160 to 200°C for extrusion, stranding, and air-cooling pelletizing to obtain masterbatch particles;

[0067] Extrusion pipe: The masterbatch particles after pelletizing are dried in a dryer at 60-80°C for 3-5 hours, and the dried masterbatch is extruded into semi-finished pipes at 150-200°C through a single screw extruder;

[0068] Irradiation process: the semi-finished pipes are irradiated by electron accelerator with an irradiation dose of 8 Mrad;

[0069] Expansion molding: The irradiated tube is expanded at a temperature of 150-180°C by an expander, and then cooled and formed to obtain a finished heat shrink tube.

[0070] Example 2

[0071] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 1, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0072] Chlorosulfonated polyethylene 1:100 parts;

[0073] Polyester elastomer: 15 parts;

[0074] Chlorinated paraffin 1: 12 parts;

[0075] Passivated Al(OH)3: 20 parts;

[0076] Dioctyl phthalate: 3.5 parts

[0077] Trimethylallyl isocyanate: 0.6 parts;

[0078] White carbon black: 20 parts.

[0079] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 1, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0080] Example 3

[0081] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 1, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0082] Chlorosulfonated polyethylene 1:100 parts;

[0083] Polyester elastomer: 30 parts;

[0084] Chlorinated paraffin 1: 12 parts;

[0085] Passivated Al(OH)3: 20 parts;

[0086] Dioctyl phthalate: 3.5 parts

[0087] Trimethylallyl isocyanate: 0.6 parts;

[0088] White carbon black: 20 parts.

[0089] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 1, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0090] Example 4

[0091] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except that the composition of each component is shown in Table 1 and Table 2:

[0092] Chlorosulfonated polyethylene 2: 100 parts;

[0093] Polyester elastomer: 15 parts;

[0094] Chlorinated paraffin 1: 12 parts;

[0095] Passivated Al(OH)3: 20 parts;

[0096] Dioctyl phthalate: 3.5 parts

[0097] Trimethylallyl isocyanate: 0.6 parts;

[0098] White carbon black: 20 parts.

[0099] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 2, except that the ingredients of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0100] Example 5

[0101] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except that the composition of each component is shown in Table 1 and Table 2:

[0102] Chlorosulfonated polyethylene 3: 100 parts;

[0103] Polyester elastomer: 15 parts;

[0104] Chlorinated paraffin 1: 12 parts;

[0105] Passivated Al(OH)3: 20 parts;

[0106] Dioctyl phthalate: 3.5 parts

[0107] Trimethylallyl isocyanate: 0.6 parts;

[0108] White carbon black: 20 parts.

[0109] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 2, except that the ingredients of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0110] Example 6

[0111] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0112] Chlorosulfonated polyethylene 1:100 parts;

[0113] Polyester elastomer: 15 parts;

[0114] Chlorinated paraffin 1:5 parts;

[0115] Passivated Al(OH)3: 20 parts;

[0116] Dioctyl phthalate: 3.5 parts

[0117] Trimethylallyl isocyanate: 0.6 parts;

[0118] White carbon black: 20 parts.

[0119] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0120] Example 7

[0121] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0122] Chlorosulfonated polyethylene 1:100 parts;

[0123] Polyester elastomer: 15 parts;

[0124] Chlorinated paraffin 1: 20 parts;

[0125] Passivated Al(OH)3: 20 parts;

[0126] Dioctyl phthalate: 3.5 parts

[0127] Trimethylallyl isocyanate: 0.6 parts;

[0128] White carbon black: 20 parts.

[0129] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0130] Example 8

[0131] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except that the ingredients of each component are shown in Table 1 and Table 2:

[0132] Chlorosulfonated polyethylene 1:100 parts;

[0133] Polyester elastomer: 15 parts;

[0134] Chlorinated paraffin 2: 12 parts;

[0135] Passivated Al(OH)3: 20 parts;

[0136] Dioctyl phthalate: 3.5 parts

[0137] Trimethylallyl isocyanate: 0.6 parts;

[0138] White carbon black: 20 parts.

[0139] The preparation method of the heat shrinkable tube of this embodiment is basically the same as that of Embodiment 2, except that the ingredients of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0140] Example 9

[0141] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except that the ingredients of each component are shown in Table 1 and Table 2:

[0142] Chlorosulfonated polyethylene 1:100 parts;

[0143] Polyester elastomer: 15 parts;

[0144] Chlorinated paraffin 3: 12 parts;

[0145] Passivated Al(OH)3: 20 parts;

[0146] Dioctyl phthalate: 3.5 parts

[0147] Trimethylallyl isocyanate: 0.6 parts;

[0148] White carbon black: 20 parts.

[0149] The preparation method of the heat shrinkable tube of this embodiment is basically the same as that of Embodiment 2, except that the ingredients of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0150] Example 10

[0151] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0152] Chlorosulfonated polyethylene 1:100 parts;

[0153] Polyester elastomer: 15 parts;

[0154] Chlorinated paraffin 1: 12 parts;

[0155] Passivated Al(OH)3: 10 parts;

[0156] Dioctyl phthalate: 3.5 parts

[0157] Trimethylallyl isocyanate: 0.6 parts;

[0158] White carbon black: 20 parts.

[0159] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0160] Embodiment 11

[0161] The raw material formula for preparing the heat shrinkable tube of this embodiment is basically the same as that of embodiment 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0162] Chlorosulfonated polyethylene 1:100 parts;

[0163] Polyester elastomer: 15 parts;

[0164] Chlorinated paraffin 1: 12 parts;

[0165] Passivated Al(OH)3: 30 parts;

[0166] Dioctyl phthalate: 3.5 parts

[0167] Trimethylallyl isocyanate: 0.6 parts;

[0168] White carbon black: 20 parts.

[0169] The preparation method of the heat shrinkable tube in this embodiment is basically the same as that in Embodiment 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0170] Comparative Example 1

[0171] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0172] Chlorosulfonated polyethylene 1:100 parts;

[0173] Polyester elastomer: 5 parts;

[0174] Chlorinated paraffin 1: 12 parts;

[0175] Passivated Al(OH)3: 20 parts;

[0176] Dioctyl phthalate: 3.5 parts

[0177] Trimethylallyl isocyanate: 0.6 parts;

[0178] White carbon black: 20 parts.

[0179] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0180] Comparative Example 2

[0181] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0182] Chlorosulfonated polyethylene 1:100 parts;

[0183] Polyester elastomer: 35 parts;

[0184] Chlorinated paraffin 1: 12 parts;

[0185] Passivated Al(OH)3: 20 parts;

[0186] Dioctyl phthalate: 3.5 parts

[0187] Trimethylallyl isocyanate: 0.6 parts;

[0188] White carbon black: 20 parts.

[0189] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0190] Comparative Example 3

[0191] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0192] Chlorosulfonated polyethylene 1:100 parts;

[0193] Polyester elastomer: 15 parts;

[0194] Chlorinated paraffin 1:2 parts;

[0195] Passivated Al(OH)3: 20 parts;

[0196] Dioctyl phthalate: 3.5 parts

[0197] Trimethylallyl isocyanate: 0.6 parts;

[0198] White carbon black: 20 parts.

[0199] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0200] Comparative Example 4

[0201] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0202] Chlorosulfonated polyethylene 1:100 parts;

[0203] Polyester elastomer: 15 parts;

[0204] Chlorinated paraffin 1: 25 parts;

[0205] Passivated Al(OH)3: 20 parts;

[0206] Dioctyl phthalate: 3.5 parts

[0207] Trimethylallyl isocyanate: 0.6 parts;

[0208] White carbon black: 20 parts.

[0209] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0210] Comparative Example 5

[0211] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except that the ingredients of each component are shown in Table 1 and Table 2:

[0212] Chlorosulfonated polyethylene 1:100 parts;

[0213] Polyester elastomer: 15 parts;

[0214] Chlorinated paraffin 4: 12 parts;

[0215] Passivated Al(OH)3: 20 parts;

[0216] Dioctyl phthalate: 3.5 parts

[0217] Trimethylallyl isocyanate: 0.6 parts;

[0218] White carbon black: 20 parts.

[0219] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the ingredients of the raw material components in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0220] Comparative Example 6

[0221] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0222] Chlorosulfonated polyethylene 1:100 parts;

[0223] Polyester elastomer: 15 parts;

[0224] Chlorinated paraffin 5: 12 parts;

[0225] Passivated Al(OH)3: 20 parts;

[0226] Dioctyl phthalate: 3.5 parts

[0227] Trimethylallyl isocyanate: 0.6 parts;

[0228] White carbon black: 20 parts.

[0229] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the ingredients of the raw material components in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0230] Comparative Example 7

[0231] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0232] Chlorosulfonated polyethylene 1:100 parts;

[0233] Polyester elastomer: 15 parts;

[0234] Chlorinated paraffin 1: 12 parts;

[0235] Passivation treated Al(OH)3: 5 parts;

[0236] Dioctyl phthalate: 3.5 parts

[0237] Trimethylallyl isocyanate: 0.6 parts;

[0238] White carbon black: 20 parts.

[0239] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0240] Comparative Example 8

[0241] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except for the mass fractions of each component, as shown in Table 1 and Table 2:

[0242] Chlorosulfonated polyethylene 1:100 parts;

[0243] Polyester elastomer: 15 parts;

[0244] Chlorinated paraffin 1: 12 parts;

[0245] Passivated Al(OH)3: 35 parts;

[0246] Dioctyl phthalate: 3.5 parts

[0247] Trimethylallyl isocyanate: 0.6 parts;

[0248] White carbon black: 20 parts.

[0249] The preparation method of the heat shrinkable tube in this comparative example is basically the same as that in Example 2, except that the mass fractions of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0250] Comparative Example 9

[0251] The raw material formula for preparing the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except that the composition and mass fraction of each component are shown in Table 1 and Table 2:

[0252] Chlorosulfonated polyethylene 1:100 parts;

[0253] Polyester elastomer: 15 parts;

[0254] Chlorinated paraffin 1: 12 parts;

[0255] Al(OH)3: 20 parts;

[0256] Dioctyl phthalate: 3.5 parts

[0257] Trimethylallyl isocyanate: 0.6 parts;

[0258] White carbon black: 20 parts.

[0259] The preparation method of the heat shrinkable tube of this comparative example is basically the same as that of Example 2, except that the composition and mass fraction of each raw material component in the masterbatch processing are different, please refer to Table 1 and Table 2.

[0260] Among them, the specific passivation treatment steps of the passivated aluminum hydroxide of Examples 1-11 and Comparative Examples 1-8 are as follows: aluminum hydroxide and boric acid with a mass ratio of 100:5 are dispersed in a methanol solution, and after stirring and ultrasonic dispersion for 30 minutes, the methanol is distilled and recovered to leave loose modified aluminum hydroxide powder.

[0261] The finished heat shrink tubing of the above embodiment and comparative example was tested for tensile strength, elongation at break, oil resistance, cold bending, and flame retardancy according to the UL224-2021 standard. Among them, the standards for reaching the standard are as follows: tensile strength ≥ 11.7MPa; elongation at break ≥ 250%; strength after aging at 150℃ / 168h ≥ 10.3MPa; elongation at break after aging at 150℃ / 168h ≥ 200%; thermal shock at 200℃ / 4h, no dripping, no sticking flow, no cracks; IRM902 oil resistance 80℃ / 60d tensile strength retention ≥ 65%; IRM902 oil resistance 80℃ / 60d elongation at break retention ≥ 65%; cold bending -65℃ / 4h no cracks; flame retardancy VW-1 passed.

[0262] Table 1 Composition and mass fraction of each raw material of the heat shrink tube prepared in the embodiment and comparative example

[0263]

[0264]

[0265]

[0266] Table 2 Test results of heat shrink tubing obtained in Examples and Comparative Examples

[0267]

[0268]

[0269]

[0270]

[0271] As can be seen from Table 2, the tensile strength of the heat shrinkable tubes prepared in Examples 1 to 11 is ≥11.7MPa, which is 13.7-16.4MPa; the elongation at break is ≥250%, which is 485-580%; the strength after aging at 150°C / 168h is ≥10.3MPa, which is 12.2-14.8Mpa; the elongation at break is ≥200% after aging at 150°C / 168h, which is 355-505%, and there is no dripping, no viscosity flow, and no cracks in the 200°C / 4h thermal shock; the tensile strength retention rate of IRM902 oil resistance at 80°C / 60d is ≥65%, which is 68.5-75.5%; the elongation at break retention rate of IRM902 oil resistance at 80°C / 60d is ≥65%, which is 67.8-71.3%; there is no crack in cold bending at -65°C / 4h; and the flame retardancy VW-1 is passed. It can be seen that the heat shrinkable tubes prepared in Examples 1 to 11 have oil resistance, high temperature resistance, low temperature resistance, and flame retardancy that all meet the requirements.

[0272] Comparative Example 1 The polyester elastomer mass fraction is too low, and the heat shrinkable tube prepared fails to pass the aging strength at 150℃ / 168h, thermal shock at 200℃ / 4h, tensile strength retention at 80℃ / 60d for IRM902 oil, elongation retention at break at 80℃ / 60d for IRM902 oil, and cold bending at -65℃ / 4h. This may be because the amount of polyester elastomer used is small, the interaction with chlorosulfonated polyethylene is not obvious, and the high temperature resistance, low temperature resistance, and oil resistance of the product are not significantly improved.

[0273] In Comparative Example 2, the mass fraction of the polyester elastomer is too high, and the flame retardant performance of the prepared heat shrinkable tube does not meet the standard, which affects the flame retardancy of the product.

[0274] Comparative Example 3: The mass fraction of chlorinated paraffin is too low, and the heat shrinkable tube prepared fails to pass the aging strength at 150°C / 168h, cold bending at -65°C / 4h, and flame retardancy VW-1. This may be because although chlorinated paraffin has the advantages of reinforcement, plasticization, and improved flame retardancy, the effect cannot be achieved with a small amount.

[0275] In Comparative Example 4, the mass fraction of chlorinated paraffin is too high, and the prepared heat shrink tubing fails to pass the 80°C / 60d tensile strength retention rate and 80°C / 60d elongation retention rate of IRM902 oil resistance. This may be because too much chlorinated paraffin destroys the internal structure of the product and affects the oil resistance of the product.

[0276] The chlorination degree of the chlorinated paraffin in Comparative Example 5 is too low, and the prepared heat shrink tubing fails to pass the strength after aging at 150°C / 168h, the thermal shock at 200°C / 4h, and the elongation retention rate at break after resistance to IRM902 oil at 80°C / 60d.

[0277] The chlorination degree of the chlorinated paraffin in Comparative Example 6 is too high. Although the flame retardant properties of the prepared heat shrinkable tube are improved, the cold bending test of -65°C / 4h fails, and the low-temperature performance deteriorates.

[0278] The mass fraction of the aluminum hydroxide in the passivation treatment of Comparative Example 7 is too low, and the prepared heat shrinkable tube fails the 200°C / 4h thermal shock test and the flame retardancy VW-1, and the flame retardancy does not meet the requirements.

[0279] Comparative Example 8 The mass fraction of aluminum hydroxide subjected to passivation treatment is too high, and the prepared heat shrinkable tube fails to pass the IRM902 oil 80℃ / 60d tensile strength retention rate, IRM902 oil 80℃ / 60d elongation retention rate, and cold bending -65℃ / 4h. This may be because the excessive amount of filler causes the material's oil resistance and low temperature resistance to deteriorate.

[0280] In Comparative Example 9, ordinary aluminum hydroxide was used instead of the passivated aluminum hydroxide, and the flame retardancy of the prepared heat shrinkable tube decreased, and the flame retardancy VW-1 failed.

[0281] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A heat shrink tube, characterized in that: The heat shrink tube preparation material includes the following raw materials in parts by weight: Chlorosulfonated polyethylene: 100 parts; Polyester elastomer: 10-30 parts.

2. The heat shrink tube according to claim 1, characterized in that: The Mooney viscosity (ML) of the chlorosulfonated polyethylene 1+4 100℃) is 50~80; Alternatively, the chlorination degree of the chlorosulfonated polyethylene is 35-45%.

3. The heat shrink tube according to claim 1, characterized in that: The melt index of the polyester elastomer is 3 to 15 g / 10 min.

4. The heat shrink tube according to claim 1, characterized in that: The heat shrink tube preparation material also includes the following raw materials in parts by weight: 5 to 20 parts of chlorinated paraffin.

5. The heat shrinkable tube according to claim 4, characterized in that: The chlorination degree of the chlorinated paraffin is 45-55%.

6. The heat shrinkable tube according to claim 4, characterized in that: The heat shrink tube preparation material also includes the following raw materials in parts by weight: 10 to 30 parts of flame retardant; the flame retardant is a metal hydroxide that has been passivated.

7. The heat shrinkable tube according to claim 1, characterized in that: The heat shrink tube preparation material also includes the following raw materials in parts by weight: 10 to 30 parts of flame retardant; the flame retardant is a metal hydroxide.

8. The heat shrinkable tube according to claim 1, characterized in that: The heat shrink tube preparation material also includes the following raw materials in parts by weight: 2 to 5 parts of a plasticizer, wherein the plasticizer is at least one of dioctyl phthalate, dioctyl adipate, dioctyl sebacate, and dibutyl phthalate; Or, 0.2 to 2 parts of a cross-linking sensitizer, wherein the cross-linking sensitizer is at least one of trimethylallyl isocyanate and its derivatives, triallyl cyanurate and its derivatives, tripropargyl cyanurate and its derivatives, trimethylolpropane trimethacrylate and its derivatives, and trimethylolpropane triacrylate and its derivatives; Or, 10-30 parts of a reinforcing agent, wherein the reinforcing agent comprises at least one of diatomaceous earth, white carbon black, carbon black, kaolin and talc.

9. A method for preparing a heat shrinkable tube as claimed in claim 1, characterized in that: The following steps are involved: Masterbatch processing: Chlorosulfonated polyethylene and polyester elastomer are mixed evenly, extruded, drawn and pelletized by extrusion equipment to obtain masterbatch particles; Extrusion into pipe: Extruding the masterbatch particles obtained above into pipes through an extrusion device to obtain semi-finished pipes; Irradiation process: irradiate the semi-finished pipes through irradiation equipment, control the irradiation dose to 5-10 Mrad, and obtain irradiated pipes; Expansion molding: the irradiated tube is expanded, cooled, and formed to obtain a finished heat shrink tube.

10. A method for preparing a heat shrinkable tube as claimed in claim 9, characterized in that: In the masterbatch processing step, when the chlorosulfonated polyethylene and the polyester elastomer are mixed, at least one of chlorinated paraffin, a flame retardant, a plasticizer, a cross-linking sensitizer, and a reinforcing agent is also added for mixing; Or, in the extrusion tube forming step, the extrusion temperature of the extrusion equipment is 150-200°C; Alternatively, in the expansion molding step, the expansion temperature is 150-180°C.

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