Matte frosted heat shrink tube and preparation method thereof

Abstract

The invention discloses a matte frosted heat shrink tube. The matte frosted heat shrink tube comprises polyethylene and polypropylene as matrix resin. The polyethylene and the polypropylene are both crystalline polymers, the blend of the polyethylene and the polypropylene is a heterogeneous system with poor compatibility, two components in the blend of the polyethylene and the polypropylene are respectively crystallized, and the crystallization speeds and the grain sizes are different, so that the blend can have a relatively obvious phase separation phenomenon, and the phase separation effect of the polyethylene and the polypropylene is greatly improved. A polypropylene short molecular chain as a dispersed phase can form a tiny concave-convex structure on a polyethylene continuous phase, and light diffusion can be caused on a two-phase interface, so that the pipe is endowed with a unique matte visual effect. According to the heat-shrinkable tube, the polyethylene accounts for 70-90 parts, the polypropylene accounts for 10-20 parts, and the mass fraction of the polyethylene is higher than that of the polypropylene, so that the matte effect of the heat-shrinkable tube can be controlled, the formed matte concave-convex structure is moderate, and the heat-shrinkable tube has good hand feeling; in addition, the mass fraction of the polyethylene is higher than that of the polypropylene, so that the processability of the heat-shrinkable tube can be improved, and better flexibility and impact resistance can be maintained. According to the matte frosted heat shrink tube, special application of the heat shrink tube with the appearance requirement can be achieved, and the mechanical performance is excellent.

Description

Technical Field

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

[0002] Heat shrink tubing is a tubing material that can shrink radially under heating conditions. It has been widely used in electronic power equipment, cable connections and other scenarios to achieve insulation protection. The surface of traditional heat shrink tubing is usually smooth and has a certain degree of transparency. However, for special occasions such as high-end electronic products, automotive wiring harnesses, and those that need to beautify the appearance of products while having a certain anti-slip effect, traditional heat shrink tubing is difficult to meet the requirements. Summary of the invention

[0003] The main purpose of the present invention is to provide a matte frosted heat shrink tube, which mainly solves the problem that the existing traditional heat shrink tube has a smooth outer surface and poor hand feel, so as to meet certain special occasions that need to beautify the appearance of the product while having a certain anti-slip effect.

[0004] The above object of the present invention is achieved through the following technical solutions:

[0005] In a first aspect of the present invention, a matte frosted heat shrinkable tube is provided, wherein the matte frosted heat shrinkable tube preparation material comprises the following raw materials in parts by weight:

[0006] Polyethylene: 70-90 parts;

[0007] Polypropylene: 10-20 parts.

[0008] In some embodiments of the present application, the polyethylene is selected from at least one of low-density polyethylene, linear low-density polyethylene, and high-density polyethylene.

[0009] In some embodiments of the present application, the polypropylene is homopolypropylene.

[0010] In some embodiments of the present application, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: nucleating agent: 0.1-5 parts.

[0011] In some embodiments of the present application, the nucleating agent is 0.1-1.5 parts.

[0012] In some embodiments of the present application, the nucleating agent includes at least one of an inorganic nucleating agent, an organic nucleating agent or an organic polymer nucleating agent.

[0013] In some embodiments of the present application, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: ethylene-vinyl acetate copolymer (EVA): 5-20 parts, with a vinyl acetate content of 10wt%-40wt%;

[0014] Or, sarling resin: 5-20 parts.

[0015] In some embodiments of the present application, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight:

[0016] Initiator: 0.1-2 parts, the initiator is at least one of azo compounds, organic peroxides, and inorganic peroxides;

[0017] Or, initiator: 0.1-1 part, the initiator is at least one of azo compounds, organic peroxides, and inorganic peroxides;

[0018] Or, antioxidant: 1-10 parts, the antioxidant is at least one of hindered phenol, hindered amine, aromatic amine, phosphite, and thioether.

[0019] In a second aspect of the present invention, a method for preparing the above-mentioned matte frosted heat shrink tube is provided, which comprises the following steps:

[0020] The first mixing and granulation: the polypropylene is mixed evenly, extruded, drawn and pelletized through an extrusion device to obtain masterbatch particles A;

[0021] Second mixing and granulation: the masterbatch particles A and polyethylene obtained by the first mixing and granulation are mixed evenly, extruded, stretched and pelletized by an extrusion device to obtain masterbatch particles B;

[0022] Extrusion into tube: The masterbatch particles B obtained by the second mixing and granulation are extruded into tubes through an extruder to obtain the original tube matte frosted heat shrink tube;

[0023] Irradiation: the extruded original tube matte frosted heat shrink tube is irradiated by irradiation equipment to obtain an irradiated tube;

[0024] Expansion and shaping: the irradiated tube is expanded by an expansion device, and then cooled and shaped to obtain a finished matte frosted heat shrink tube.

[0025] In some embodiments of the present application, during the first mixing and granulation, when the polypropylene is mixed, an initiator is also added for mixing;

[0026] Or, in the first mixing and granulation, the extrusion temperature of the extrusion equipment is 180-240°C;

[0027] Or, in the second mixing and granulation, when the masterbatch particles A and polyethylene are mixed, a nucleating agent and an antioxidant are also added for mixing;

[0028] Or, in the second mixing and granulation, the extrusion temperature of the extrusion equipment is 180-240°C;

[0029] Or, in the extrusion into a tube, the extrusion temperature of the extrusion equipment is 180-250°C;

[0030] Or, in the irradiation step, the irradiation dose is 50-150 KGy;

[0031] Alternatively, in the expansion and shaping step, the expansion temperature of the expansion device is 130-160°C.

[0032] The matte frosted heat shrinkable tube of the present invention includes polyethylene and polypropylene as the matrix resin. Since both polyethylene and polypropylene are crystalline polymers, their blend is a multiphase system with poor compatibility, and the two components in the polyethylene and polypropylene blend are crystallized separately, and the crystallization speed and grain size are different. Therefore, the blend will have a more obvious phase separation phenomenon. The short molecular chain of polypropylene as the dispersed phase will form a tiny concave-convex structure on the polyethylene continuous phase, which will cause light diffusion at the interface between the two phases, thereby giving the tube a unique matte visual effect. In the present invention, polyethylene is 70-90 parts and polypropylene is 10-20 parts. The mass fraction of polyethylene is higher than the mass fraction of polypropylene, which can control the matte effect of the heat shrinkable tube, so that the concave-convex structure formed on the matte surface is moderate and has a good feel; in addition, the mass fraction of polyethylene is higher than the mass fraction of polypropylene, which can also improve the processability of the heat shrinkable tube and maintain good flexibility and impact resistance. The matte frosted heat shrinkable tube of the present invention can realize the specialized application of the heat shrinkable tube with requirements for appearance, and has excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a microscope photo of the outer surface of the matte frosted heat shrink tube prepared in Example 1 of the present invention;

[0034] Figure 2 This is a microscope photo of the outer surface of the matte frosted heat shrink tube prepared in Comparative Example 1 of the present invention;

[0035] Figure 3 This is a microscope photograph of the outer surface of the matte frosted heat shrink tube prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0036] 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.

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] 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.

[0039] Heat shrink tubing has excellent properties such as high temperature shrinkage, insulation and corrosion resistance, and wear resistance. It is widely used in electronic equipment, wiring harnesses, military industry, communications, medical and other fields. At present, for ordinary application fields, heat shrink tubing with a smooth outer surface can basically meet the needs. With the development of modern technology, people have put forward special requirements for the appearance of heat shrink tubing. Conventional heat shrink tubing has a smooth outer surface and a poor feel, which makes it difficult to meet certain application fields with special requirements for appearance.

[0040] Based on this, the first aspect of the present invention provides a matte frosted heat shrinkable tube, and the matte frosted heat shrinkable tube preparation material includes the following raw materials in parts by weight:

[0041] Polyethylene: 70-90 parts;

[0042] Polypropylene: 10-20 parts.

[0043] In some embodiments, the polyethylene is selected from at least one of low-density polyethylene, linear low-density polyethylene, and high-density polyethylene.

[0044] Polyethylene (PE) is a thermoplastic resin obtained by polymerization of ethylene. Polyethylene (PE) can be divided into high-density polyethylene (HDPE), low-density polyethylene (LDPE) and linear low-density polyethylene (LLDPE) according to density. High-density polyethylene molecules are linear structures with little branching. They are typical crystalline polymers with better mechanical properties than low-density polyethylene. The melting point is higher than that of low-density polyethylene, which is 126℃-136℃, and the brittle temperature is lower than that of low-density polyethylene, which is -100℃~-140℃. The density of low-density polyethylene is 0.91-0.94g / cm 3 , there are long side chains in the molecules, and the molecules are not tightly arranged. Linear low-density polyethylene generally has only short side chains in its molecules, and its mechanical properties are between high-density and low-density polyethylene. Its melting point is 15°C higher than that of ordinary low-density polyethylene, and its low-temperature resistance is also better than that of low-density polyethylene. Its environmental stress cracking resistance is 10 times higher than that of ordinary low-density polyethylene. All three types of polyethylene are crystalline polymers.

[0045] In some embodiments, the polypropylene is homopolypropylene.

[0046] According to the different polymerization methods, polypropylene can be divided into homopolymer polypropylene, block copolymer polypropylene and random copolymer polypropylene. Homopolymer polypropylene is polymerized from a single propylene monomer, with high molecular chain regularity, high crystallinity and good strength. Random copolymer polypropylene is copolymerized from propylene monomer and a small amount of ethylene monomer. The random addition of ethylene monomer reduces the crystallinity and melting point of the polymer, improves the impact performance and long-term heat and oxygen aging resistance of the material. Block copolymer polypropylene has a high ethylene content, better impact resistance and a certain rigidity, but has low transparency, low gloss and poor oxidation resistance at high temperatures.

[0047] Since polyethylene and homopolypropylene are both crystalline polymers, their blends are multiphase systems with poor compatibility, and the two components in the polyethylene and homopolypropylene blends are crystallized separately, with different crystallization speeds and grain sizes. Therefore, the blends will show a more obvious phase separation phenomenon, and the short molecular chains of polypropylene as dispersed phases will form tiny concave-convex structures on the polyethylene continuous phase, which will cause light diffusion on the grain interface, thereby giving the pipe a unique matte visual effect. In the present invention, polyethylene is 70-90 parts and polypropylene is 10-20 parts, and the mass fraction of polyethylene is higher than that of polypropylene, which can control the matte effect of the heat shrinkable tube, so that the concave-convex structure formed on the matte surface is moderate and has a good feel; in addition, the mass fraction of polyethylene is higher than that of polypropylene, which can also improve the processability of the heat shrinkable tube and maintain good flexibility and impact resistance.

[0048] In some embodiments, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: nucleating agent: 0.1-5 parts.

[0049] In some embodiments, the nucleating agent is 0.1-1.5 parts.

[0050] In some embodiments, the nucleating agent includes at least one of an inorganic nucleating agent, an organic nucleating agent, or an organic polymer nucleating agent.

[0051] There are three types of nucleating agents: inorganic, organic and polymer:

[0052] ①Inorganic nucleating agent

[0053] Inorganic nucleating agents are mainly talc, and also include: CaCO3, mica, inorganic pigments, etc.

[0054] ②Organic nucleating agent

[0055] The main organic nucleating agents are: metal aromatic carboxylates such as sodium, magnesium, aluminum, titanium, organic phosphates, sorbitol sugars, etc.

[0056] ③Organic polymer nucleating agent

[0057] Organic polymer nucleating agents are some high melting point polymers, such as vinyl cycloalkanes.

[0058] The addition of nucleating agents mainly promotes heterogeneous nucleation, increases crystal growth points, improves crystallinity, and makes crystal particles finer, promotes the formation of microcrystals, which can change the light transmittance and haze of the material, while making the polymer chain stacking more dense and enhancing the intermolecular force. Therefore, the addition of nucleating agents can improve the tensile strength of heat shrink tubing. Furthermore, the mass fraction of nucleating agents will affect the matte frosted surface morphology of heat shrink tubing. For inorganic nucleating agents, if the mass fraction is too high, it will cause it to be difficult to disperse in the polymer, easy to agglomerate, and have a shielding effect on light, resulting in a significant decrease in the light transmittance of the heat shrink tubing and color staining; while for organic nucleating agents, if the mass fraction is too high, it may lead to too fast crystallization speed, too small grain size, and even smaller than the wavelength of visible light, resulting in a significant increase in the light transmittance of the heat shrink tubing and an almost completely transparent state.

[0059] In some embodiments, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: 5-20 parts of ethylene-vinyl acetate copolymer (EVA), with a vinyl acetate content of 10wt%-40wt%.

[0060] In some embodiments, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: 5-20 parts of Surlyn resin.

[0061] Ethylene-vinyl acetate copolymer and Surlyn resin have very low crystallinity and good transparency. Surlyn resin is a kind of ethylene-methacrylic acid copolymer (EMAA) partially ionized with metal ions (Zn 2+ Or Na + or Li + ) is a thermoplastic resin containing covalent bonds made by neutralization.

[0062] Since polypropylene is brittle at low temperatures, has high rigidity and insufficient toughness, while ethylene-vinyl acetate copolymer and sarling resin have good flexibility and low temperature resistance, adding ethylene-vinyl acetate copolymer or sarling resin can make up for the adverse effects of polypropylene, and can effectively improve the low temperature resistance and toughness of the heat shrink tube. Furthermore, the mass fraction of ethylene-vinyl acetate copolymer or sarling resin will affect the matte frosted surface morphology of the heat shrink tube. If the mass fraction of ethylene-vinyl acetate copolymer or sarling resin is too much, the concave-convex structure size of the outer surface of the heat shrink tube will be too small, and it will almost feel smooth, without frosted texture, and the color will be relatively transparent.

[0063] In some embodiments, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: initiator: 0.1-2 parts, the initiator is at least one of an azo compound, an organic peroxide, and an inorganic peroxide.

[0064] Azo initiators include azobisisobutyronitrile (AIBN), 2,2-azobis(2,4-dimethylvaleronitrile), etc.

[0065] Organic peroxide initiators include dibenzoyl peroxide (BPO), di-tert-butyl peroxide (DTBP), isopropyl peroxide (DCP), tert-butyl hydroperoxide (TBH), isopropyl hydroperoxide (CHP), diisopropyl monohydroperoxide, tert-butyl peroxycarboxylate, diisopropyl peroxydicarbonate (IPP), di(2-ethylhexyl) peroxydicarbonate (EHP), etc.

[0066] Inorganic peroxide initiators include persulfates (potassium, sodium or ammonium salts), hydrogen peroxide and the like.

[0067] In some embodiments, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: 0.1-1 part of initiator.

[0068] In some embodiments, the matte frosted heat shrink tube preparation material further includes the following materials in parts by weight: antioxidant: 1-10 parts, the antioxidant is at least one of hindered phenol, hindered amine, aromatic amine, phosphite, and thioether.

[0069] Hindered phenol antioxidants include antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), BHT (2,6-di-tert-butyl-p-cresol), antioxidant 1076 (β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate), etc.

[0070] Hindered amine antioxidants include GW-480 (770), GW-622, GW-944, GW-783, etc.

[0071] 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);

[0072] Phosphite antioxidants include antioxidant 168 (tris[2,4-di-tert-butylphenyl]phosphite), antioxidant 618 (pentaerythritol dioctadecyl diphosphite), antioxidant 626 (bis[2,4-di-tert-butylphenyl]pentaerythritol diphosphite), etc.

[0073] Thioether antioxidants include pentaerythritol tetra(3-lauryl thioacrylate), distearyl thiodipropionate, dilauryl thiodipropionate (DLTP), di(tridecaproyl)thiodipropionate, and the like.

[0074] By adding antioxidants, the anti-oxidation and aging resistance of the frosted heat shrink tube can be improved, and the service life of the frosted heat shrink tube can be extended.

[0075] In a second aspect of the present invention, a method for preparing the above-mentioned matte frosted heat shrink tube is provided, which comprises the following steps:

[0076] The first mixing and granulation: the polypropylene is mixed evenly, extruded, drawn and pelletized through an extrusion device to obtain masterbatch particles A;

[0077] Second mixing and granulation: the masterbatch particles A and polyethylene obtained by the first mixing and granulation are mixed evenly, extruded, stretched and pelletized by an extrusion device to obtain masterbatch particles B;

[0078] Extrusion into tube: The masterbatch particles B obtained by the second mixing and granulation are extruded into tubes through an extruder to obtain the original tube matte frosted heat shrink tube;

[0079] Irradiation: the extruded original tube matte frosted heat shrink tube is irradiated by irradiation equipment to obtain an irradiated tube;

[0080] Expansion and shaping: the irradiated tube is expanded by an expansion device, and then cooled and shaped to obtain a finished matte frosted heat shrink tube.

[0081] It can be understood that the first mixing and granulation: polypropylene can be added into a high-speed mixer and mixed evenly, and then extruded through an extrusion device, such as a twin-screw extruder or a single-screw extruder, stretched, and pelletized to obtain masterbatch particles A;

[0082] Second mixing and granulation: add masterbatch particles A and polyethylene into a high-speed mixer and mix them evenly, then extrude them through an extrusion device, such as a twin-screw extruder or a single-screw extruder, draw them into strips, cut them into pellets, and obtain masterbatch particles B;

[0083] Extrusion into tubes: The masterbatch particles B obtained by the second mixing and granulation are passed through an extruder, such as a single-screw extruder or a twin-screw extruder, to extrude a tube to obtain a semi-finished tube;

[0084] Irradiation: The semi-finished pipes are subjected to irradiation equipment, such as an electron accelerator irradiation device or a radioisotope irradiation device, and the irradiation dose is controlled to be 50-150KGy to obtain irradiated pipes;

[0085] Expansion molding: the irradiated tube is expanded, cooled, and formed to obtain a finished matte frosted heat shrink tube.

[0086] In some embodiments of the present application, during the first mixing and granulation, when the polypropylene is mixed, an initiator is also added for mixing;

[0087] Or, in the first mixing and granulation, the extrusion temperature of the extrusion equipment is 180-240°C;

[0088] Or, in the second mixing and granulation, when the masterbatch particles A and polyethylene are mixed, a nucleating agent and an antioxidant are also added for mixing;

[0089] Or, in the second mixing and granulation, the extrusion temperature of the extrusion equipment is 180-240°C;

[0090] Or, in the extrusion into a tube, the extrusion temperature of the extrusion equipment is 180-250°C;

[0091] Or, in the irradiation step, the irradiation dose is 50-150 KGy;

[0092] Alternatively, in the expansion and shaping step, the expansion temperature of the expansion device is 130-160°C.

[0093] It is understandable that during the first granulation, mechanical stress is easily concentrated on the tertiary carbon-secondary carbon bond of the polypropylene chain, breaking the polypropylene macromolecule chain into polypropylene short molecular chains with relatively low molecular weight; then polyethylene is added during the second granulation to evenly disperse the polypropylene short molecular chains in the polyethylene, forming a "sea-island" structure with polypropylene short molecular chains as the dispersed phase and polyethylene as the continuous phase. The "sea-island" structure is a heterogeneous system, in which one polymer is distributed in the continuous phase of another polymer in the form of a fine dispersed phase. When light passes through a blend with a "sea-island" structure, the "sea-island" structure can change the transparency and gloss of the material due to the different scattering and refraction of light by the dispersed phase and the continuous phase. In addition, the presence of the dispersed phase may also cause irregularities on the material surface, thereby affecting the roughness and friction coefficient of the material surface. Furthermore, during the first granulation, an initiator is added, and the initiator decomposes into free radicals under the action of heat. The free radicals mainly attack the tertiary carbon-secondary carbon bonds of polypropylene with stress concentration, causing the molecular chain to break, so that the polypropylene chain breaks into short polypropylene molecular chains with relatively low molecular weight; during the second granulation, an antioxidant is added, firstly, it can capture the free radicals and initiators that have not yet expired in the masterbatch A, and prevent the free radicals from continuing to attack the polypropylene and causing further chain breakage; secondly, it can capture the free radicals generated by the degradation of the short polypropylene molecular chains during irradiation, and prevent the further degradation of the polypropylene during the irradiation process; thirdly, it can improve the heat resistance and aging resistance of the heat shrinkable tube during processing and use.

[0094] Optical microscope inspection of the outer surface of matte heat shrink tube

[0095] The roughness of the outer surface of the matte frosted heat shrink tube was tested under a high-quality SZM-45B1 optical microscope at 8-10 times magnification. Figure 1 , Figure 2 , Figure 3 . Figure 1 There are a lot of tiny concave and convex structures on the outer surface of the heat shrink tube, with a frosted texture and a matte appearance, which has a good feel, can increase the friction of the outer surface of the heat shrink tube and reduce the reflectivity; Figure 2 Although the heat shrink tube also has a concave-convex structure, its size is too small, and it feels almost smooth, without a frosted texture, and its color is relatively transparent, which cannot increase the friction of the outer surface of the heat shrink tube and reduce the reflectivity; Figure 3 Although the outer surface of the heat shrink tube also has a concave and convex structure, the size is too large, there is a clear granular feel, the roughness is too strong, and the feel is not good.

[0096] The present invention is further described in detail below with reference to specific embodiments.

[0097] Example 1

[0098] Please refer to Table 1. The matte frosted heat shrink tube of this embodiment includes the following raw materials in parts by weight:

[0099] Low density polyethylene: 70 parts;

[0100] Homopolymer polypropylene: 20 parts.

[0101] The preparation method of the matte frosted heat shrink tube is as follows:

[0102] First mixing and granulation: homopolymer polypropylene is added into a high-speed mixer and mixed evenly, and then extruded, stretched and pelletized by a twin-screw extruder at a temperature of 180-240°C to obtain masterbatch particles A;

[0103] Second mixing and granulation: the masterbatch particles A and low-density polyethylene obtained by the first mixing and granulation are added into a high-speed mixer and mixed evenly, and then extruded, stretched and pelletized by a twin-screw extruder at a temperature of 180-240°C to obtain masterbatch particles B;

[0104] Extrusion into tube: The masterbatch particles B obtained by the second mixing and granulation are extruded through a single screw extruder at an extrusion temperature of 180-250° C. to obtain an original tube matte frosted heat shrink tube;

[0105] Irradiation: The extruded original tube matte frosted heat shrink tube is irradiated by an electron accelerator or a cobalt source, and the irradiation dose is controlled to be 100KGy to obtain an irradiated tube;

[0106] Expansion and shaping: the irradiated tube is expanded at 130-160°C using an expansion device, and then cooled and shaped to obtain a finished matte frosted heat shrink tube.

[0107] Example 2

[0108] The raw material formula for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Example 1, except for the number of components, as shown in Table 1:

[0109] Low density polyethylene: 80 parts;

[0110] Homopolymer polypropylene: 15 parts.

[0111] The method for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Embodiment 1, except that the portions of each raw material component in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0112] Example 3

[0113] The raw material formula for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Example 1, except for the number of components, as shown in Table 1:

[0114] Low density polyethylene: 90 parts;

[0115] Homopolymer polypropylene: 10 parts.

[0116] The method for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Embodiment 1, except that the portions of each raw material component in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0117] Example 4

[0118] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 1, except for the composition and quantity of each component, as shown in Table 1:

[0119] High density polyethylene: 80 parts;

[0120] Homopolymer polypropylene: 15 parts.

[0121] The method for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 1, except that the ingredients and proportions of the raw material components in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0122] Example 5

[0123] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 1, except for the composition and quantity of each component, as shown in Table 1:

[0124] Low density polyethylene: 40 parts;

[0125] High density polyethylene: 40 parts;

[0126] Homopolymer polypropylene: 15 parts.

[0127] The method for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 1, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0128] Example 6

[0129] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0130] Low density polyethylene: 80 parts;

[0131] Homopolymer polypropylene: 15 parts;

[0132] Talc: 0.1 parts.

[0133] The method for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0134] Example 7

[0135] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0136] Low density polyethylene: 80 parts;

[0137] Homopolymer polypropylene: 15 parts;

[0138] Talc: 1.5 parts.

[0139] The method for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0140] Example 8

[0141] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0142] Low density polyethylene: 80 parts;

[0143] Homopolymer polypropylene: 15 parts;

[0144] Talc: 5 parts.

[0145] The method for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0146] Example 9

[0147] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0148] Low density polyethylene: 80 parts;

[0149] Homopolymer polypropylene: 15 parts;

[0150] Ethylene-vinyl acetate copolymer: 5 parts.

[0151] The method for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0152] Example 10

[0153] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0154] Low density polyethylene: 80 parts;

[0155] Homopolymer polypropylene: 15 parts;

[0156] Ethylene-vinyl acetate copolymer: 12 parts.

[0157] The method for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0158] Embodiment 11

[0159] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0160] Low density polyethylene: 80 parts;

[0161] Homopolymer polypropylene: 15 parts;

[0162] Ethylene-vinyl acetate copolymer: 20 parts.

[0163] The method for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0164] Example 12

[0165] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0166] Low density polyethylene: 80 parts;

[0167] Homopolymer polypropylene: 15 parts;

[0168] Initiator: 0.1 part;

[0169] Antioxidant 1010: 5 parts;

[0170] Antioxidant DLTP: 5 parts.

[0171] The method for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0172] Example 13

[0173] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0174] Low density polyethylene: 80 parts;

[0175] Homopolymer polypropylene: 15 parts;

[0176] Initiator DCP: 2 parts;

[0177] Antioxidant 1010: 2 parts;

[0178] Antioxidant DLTP: 2 parts

[0179] The method for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0180] Embodiment 14

[0181] The raw material formula for preparing the matte frosted heat shrink tube of this embodiment is basically the same as that of embodiment 2, except for the composition and quantity of each component, as shown in Table 1:

[0182] Low density polyethylene: 80 parts;

[0183] Homopolymer polypropylene: 15 parts;

[0184] Talc: 1 part;

[0185] Nucleating agent 3988: 2 parts;

[0186] Ethylene-vinyl acetate copolymer: 18 parts;

[0187] Initiator DCP: 1 part;

[0188] Antioxidant 1010: 0.5 parts;

[0189] Antioxidant DLTP: 0.5 parts

[0190] The method for preparing the matte frosted heat shrink tube in this embodiment is basically the same as that in Embodiment 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0191] Comparative Example 1

[0192] The raw material formula for preparing the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except for the composition and number of each component, as shown in Table 1:

[0193] Low density polyethylene: 80 parts;

[0194] Copolymer polypropylene: 15 parts.

[0195] The preparation method of the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0196] Comparative Example 2

[0197] The raw material formula for preparing the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except for the composition and number of each component, as shown in Table 1:

[0198] Low density polyethylene: 80 parts;

[0199] Homopolymer polypropylene: 30 parts.

[0200] The preparation method of the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0201] Comparative Example 3

[0202] The raw material formula for preparing the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except for the composition and number of each component, as shown in Table 1:

[0203] Low density polyethylene: 80 parts;

[0204] Homopolymer polypropylene: 5 parts.

[0205] The preparation method of the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0206] Comparative Example 4

[0207] The raw material formula for preparing the heat shrink tube of this comparative example is basically the same as that of Example 2, except that the composition and number of each component are shown in Table 1:

[0208] Low density polyethylene: 80 parts.

[0209] The preparation method of the heat shrinkable tube of this comparative example is as follows:

[0210] Mixing and granulation: Add low-density polyethylene into a high-speed mixer and mix evenly, then extrude, draw and pelletize through a twin-screw extruder at a temperature of 180-240°C to obtain masterbatch particles;

[0211] Extrusion into tube: The masterbatch particles are extruded through a single screw extruder at an extrusion temperature of 180-250°C to obtain an original tube heat shrink tube;

[0212] Irradiation: The extruded original heat shrink tube is irradiated by an electron accelerator or a cobalt source, and the irradiation dose is controlled to be 100 KGy to obtain an irradiated tube;

[0213] Expansion and shaping: the irradiated tube is expanded at 130-160°C using an expansion device, and then cooled and shaped to obtain a finished heat shrink tube.

[0214] Comparative Example 5

[0215] The raw material formula for preparing the heat shrink tube of this comparative example is basically the same as that of Example 2, except that the composition and number of each component are shown in Table 1:

[0216] Homopolymer polypropylene: 15 parts.

[0217] The preparation method of the heat shrinkable tube of this comparative example is as follows:

[0218] Mixing and granulation: homopolymer polypropylene is added into a high-speed mixer and mixed evenly, and then extruded, stretched and pelletized by a twin-screw extruder at a temperature of 180-240°C to obtain masterbatch particles;

[0219] Extrusion into tube: The masterbatch particles are extruded through a single screw extruder at an extrusion temperature of 180-250°C to obtain an original tube heat shrink tube;

[0220] Irradiation: The extruded original heat shrink tube is irradiated by an electron accelerator or a cobalt source, and the irradiation dose is controlled to be 100 KGy to obtain an irradiated tube;

[0221] Expansion and shaping: the irradiated tube is expanded at 130-160°C using an expansion device, and then cooled and shaped to obtain a finished heat shrink tube.

[0222] Comparative Example 6

[0223] The raw material formula for preparing the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except for the composition and number of each component, as shown in Table 1:

[0224] Low density polyethylene: 80 parts;

[0225] Homopolymer polypropylene: 15 parts;

[0226] Talc: 8 parts.

[0227] The preparation method of the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0228] Comparative Example 7

[0229] The raw material formula for preparing the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except for the composition and number of each component, as shown in Table 1:

[0230] Low density polyethylene: 80 parts;

[0231] Homopolymer polypropylene: 15 parts;

[0232] Ethylene-vinyl acetate copolymer: 30 parts.

[0233] The preparation method of the matte frosted heat shrink tube of this comparative example is basically the same as that of Example 2, except that the components and proportions of the raw materials in the first mixing and granulation and the second mixing and granulation are different, see Table 1.

[0234] The finished matte frosted heat shrink tubes of the above embodiments and comparative examples were tested for light transmittance and haze according to GB / T2410-2008 standard requirements. In addition, the finished matte frosted heat shrink tubes were tested for tensile strength, elongation at break, low temperature flexibility and thermal shock according to the national military standard GJB7279-2011 standard requirements.

[0235] The optical microscope photos of the heat shrink tubes prepared in Examples 1-14 are similar. Figure 1 As shown; the optical microscope photographs of the heat shrinkable tubes prepared in Comparative Examples 1, 3, 4, and 7 are not much different, and the optical microscope photograph of the heat shrinkable tube prepared in Comparative Example 1 is as shown Figure 2 As shown; Comparative Examples 2 and 6 have similar optical microscope photographs of heat shrinkable tubes. The optical microscope photograph of the heat shrinkable tube prepared in Comparative Example 2 is as shown Figure 3As shown; Comparative Example 5 does not contain polyethylene, so a heat shrink tube cannot be formed and cannot be compared.

[0236] Table 1 Composition and mass fraction of each raw material of matte frosted heat shrink tube prepared in Examples and Comparative Examples

[0237]

[0238]

[0239]

[0240]

[0241] Table 2 Test results of frosted heat shrink tube GJB7279-2011 prepared in the examples and comparative examples

[0242]

[0243]

[0244]

[0245] As shown in Table 2, the light transmittance of the matte frosted heat shrink tubes prepared in Examples 1 to 14 is between 67.5% and 78.7%, and the haze is between 40.2% and 63.8%. The optical microscope photos are not much different. The photo of Example 1 is as shown in FIG. Figure 1 As shown, there are a large number of tiny concave-convex structures on the outer surface, frosted texture, matte appearance, good hand feel, increased friction on the outer surface of the heat shrink tube and reduced reflectivity. It can be seen that the tube with transmittance and haze within this range has a good matte frosted surface. The tensile strength, elongation at break, thermal shock and low-temperature flexibility are measured according to the GJB7279-2011 standard requirements. The tensile strength is required to be not less than 10.4MPa, the elongation at break is not less than 200%, the test surface after the low-temperature flexibility test should be free of cracks, and the sample surface after the thermal shock test should be free of cracks, flow and dripping. As shown in Table 2, Example 14, in which ethylene-vinyl acetate copolymer and antioxidant are added at the same time, fully meets the requirements of the GJB7279-2011 standard.

[0246] Comparative Example 1 uses copolymerized polypropylene as the base resin. The light transmittance of the prepared heat shrink tube is too high, higher than 78.7%, and the haze is too low, less than 40.2%. Figure 2 As shown, although there are concave and convex structures, the size is too small, the feel is almost smooth, there is no frosted texture, the color is relatively transparent, and it cannot increase the friction of the outer surface of the heat shrink tube and reduce the reflectivity.

[0247] Although homopolymer polypropylene is used as the matrix resin in Comparative Example 2, the transmittance of the prepared heat shrink tube is too low, less than 67.5%, and the haze is too large, greater than 63.8%, due to the excessively high mass fraction of homopolymer polypropylene. Figure 3 As shown, although there are concave and convex structures on the outer surface, the size is too large, there is a clear graininess, the roughness is too strong, and the feel is not good.

[0248] Although comparative example 3 also uses homopolymer polypropylene as the matrix resin, the mass fraction of homopolymer polypropylene is too low, resulting in the prepared heat shrink tube having too high light transmittance, higher than 78.7%, and too low haze, less than 40.2%. Figure 2 Similar, although there are also concave and convex structures, the size is too small, it feels almost smooth, has no frosted texture, and the color is relatively transparent, which cannot increase the friction of the outer surface of the heat shrink tube and reduce the reflectivity.

[0249] Comparative Example 4 did not add homopolymerized polypropylene, resulting in the heat shrink tube having a too high light transmittance, higher than 78.7%, and a too low haze, less than 40.2%. Figure 2 Similar, although there are also concave and convex structures, the size is too small, it feels almost smooth, has no frosted texture, and the color is relatively transparent, which cannot increase the friction of the outer surface of the heat shrink tube and reduce the reflectivity.

[0250] Although homopolymer polypropylene is used as the matrix resin in Comparative Example 6, the mass fraction of the added inorganic nucleating agent is too high, resulting in the prepared heat shrink tube having too low light transmittance, lower than 67.5%, and too high haze, greater than 63.8%. Figure 3 Similarly, although there are also concave and convex structures on the outer surface, the size is too large, there is a clear grainy feel, the roughness is too strong, and the feel is not good.

[0251] Although homopolymer polypropylene is used as the matrix resin in Comparative Example 7, the mass fraction of ethylene-vinyl acetate copolymer added is too high, resulting in the prepared heat shrink tube having too high light transmittance, higher than 78.7%, and too low haze, less than 40.2%. Figure 2 Similar, although there are also concave and convex structures, the size is too small, it feels almost smooth, has no frosted texture, and the color is relatively transparent, which cannot increase the friction of the outer surface of the heat shrink tube and reduce the reflectivity.

[0252] 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 and drawings, 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 frosted heat shrink tube, characterized in that: The matte frosted heat shrink tube preparation material includes the following raw materials in parts by weight: Polyethylene: 70-90 parts; Polypropylene: 10-20 parts.

2. The matte frosted heat shrink tube according to claim 1, characterized in that: The polyethylene is selected from at least one of low-density polyethylene, linear low-density polyethylene, and high-density polyethylene.

3. The matte frosted heat shrink tube according to claim 1, characterized in that: The polypropylene is homopolymer polypropylene.

4. The matte frosted heat shrink tube according to claim 1, characterized in that: The matte frosted heat shrink tube preparation material also includes the following materials in parts by weight: 0.1-5 parts of a nucleating agent.

5. The matte frosted heat shrink tube according to claim 4, characterized in that: The nucleating agent is 0.1-1.5 parts.

6. The matte frosted heat shrink tube according to claim 4 or 5, characterized in that: The nucleating agent includes at least one of an inorganic nucleating agent, an organic nucleating agent or an organic polymer nucleating agent.

7. The matte frosted heat shrink tube according to claim 1, characterized in that: The matte frosted heat shrink tube preparation material also includes the following materials in parts by weight: Ethylene-vinyl acetate copolymer (EVA): 5-20 parts, vinyl acetate content is 10wt%-40wt%; Or, sarling resin: 5-20 parts.

8. The matte frosted heat shrink tube according to claim 1, characterized in that: The matte frosted heat shrink tube preparation material also includes the following materials in parts by weight: Initiator: 0.1-2 parts, the initiator is at least one of azo compounds, organic peroxides, and inorganic peroxides; Or, initiator: 0.1-1 part, the initiator is at least one of azo compounds, organic peroxides, and inorganic peroxides; Or, antioxidant: 1-10 parts, the antioxidant is at least one of hindered phenol, hindered amine, aromatic amine, phosphite, and thioether.

9. A method for preparing a matte frosted heat shrink tube as claimed in claim 1, characterized in that: The following steps are involved: The first mixing and granulation: the polypropylene is mixed evenly, extruded, drawn and pelletized through an extrusion device to obtain masterbatch particles A; Second mixing and granulation: the masterbatch particles A and polyethylene obtained by the first mixing and granulation are mixed evenly, extruded, stretched and pelletized by an extrusion device to obtain masterbatch particles B; Extrusion into tube: The masterbatch particles B obtained by the second mixing and granulation are extruded into tubes through an extruder to obtain the original tube matte frosted heat shrink tube; Irradiation: the extruded original tube matte frosted heat shrink tube is irradiated by irradiation equipment to obtain an irradiated tube; Expansion and shaping: the irradiated tube is expanded by an expansion device, and then cooled and shaped to obtain a finished matte frosted heat shrink tube.

10. A method for preparing a matte frosted heat shrink tube as claimed in claim 9, characterized in that: In the first mixing and granulation, when the polypropylene is mixed, an initiator is also added for mixing; Or, in the first mixing and granulation, the extrusion temperature of the extrusion equipment is 180-240°C; Or, in the second mixing and granulation, when the masterbatch particles A and polyethylene are mixed, a nucleating agent and an antioxidant are also added for mixing; Or, in the second mixing and granulation, the extrusion temperature of the extrusion equipment is 180-240°C; Or, in the extrusion into a tube, the extrusion temperature of the extrusion equipment is 180-250°C; Or, in the irradiation step, the irradiation dose is 50-150 KGy; Alternatively, in the expansion and shaping step, the expansion temperature of the expansion device is 130-160°C.

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