A cross-linked high-density polyethylene composite material and preparation method thereof

Abstract

The present invention provides a cross-linked high-density polyethylene composite material and a preparation method thereof, belonging to the technical field of composite materials. The raw materials of the cross-linked high-density polyethylene composite material provided by the present invention include: 100 parts of high-density polyethylene resin, 0.1-0.3 parts of organic peroxide cross-linking agent, 0.3-0.7 parts of auxiliary cross-linking agent, 0.2-2 parts of photosensitizer and 0.3-0.5 parts of other auxiliary agents. The present invention adds a photosensitizer to absorb ultraviolet energy of a certain wavelength to stimulate the high-density polyethylene macromolecular chain to generate free radicals, and the auxiliary cross-linking agent can further induce the cross-linking reaction of free radicals between high-density polyethylene macromolecular chains; the organic peroxide cross-linking agent can make full use of the surplus heat of the ultraviolet cross-linking furnace, and a cross-linking reaction occurs in the deep material that ultraviolet light cannot penetrate, and the cross-linking thickness is thicker than that of the simple ultraviolet cross-linked high-density polyethylene material, and the overall cross-linking degree is higher and more uniform.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and in particular to a cross-linked high-density polyethylene composite material and a preparation method thereof. Background Art

[0002] Polyethylene is one of the five general-purpose plastics and is often used in the preparation of pipes. However, polyethylene is sensitive to environmental stress and has poor heat resistance and creep resistance. For example, ordinary high-density polyethylene pipes are not suitable for conveying media with a temperature greater than 45°C. This property limits its application in certain fields.

[0003] Studies have shown that cross-linked high-density polyethylene composite materials, such as cross-linked high-density polyethylene pipes (PEX), have greatly improved creep resistance and environmental stress cracking resistance (ESCR). At present, the cross-linking processes of PEX pipes include peroxide cross-linked polyethylene (PE-Xa), silane cross-linked polyethylene (PE-Xb), electron beam cross-linked polyethylene (PE-Xc), azo cross-linked polyethylene (PE-Xd) and ultraviolet cross-linked polyethylene (PE-Xe). Among them, PE-Xe is to add a photoinitiator to the polyethylene resin. Under ultraviolet light irradiation, the photoinitiator absorbs ultraviolet light of a specific wavelength to generate polyolefin free radicals, thereby generating a series of rapid cross-linking reactions to generate cross-linked polyolefins with a three-dimensional network structure; this process has the advantages of fast reaction speed, excellent comprehensive performance of pipes and environmental protection, and has attracted much attention from researchers. Traditional ultraviolet light sources use high-pressure mercury lamps, which have the disadvantages of short life and risks caused by mercury vapor leakage. Modern ultraviolet light sources mainly use UV LEDs, which have the advantages of long life, no toxic gas leakage, and low cost. However, UV LED lamps are accompanied by a large amount of heat rays while generating ultraviolet rays. In addition to ensuring that the cross-linked embryo reaches the necessary temperature, the excess heat energy is not fully utilized, resulting in heat energy loss. In addition, due to the limited penetration ability of ultraviolet light, during the ultraviolet light cross-linking process, the surface cross-linking degree of the high-density polyethylene material may be higher, while the deep cross-linking degree is lower, which may be uneven. Summary of the invention

[0004] The object of the present invention is to provide a cross-linked high-density polyethylene composite material and a preparation method thereof. The cross-linked high-density polyethylene composite material provided by the present invention can utilize the surplus heat energy of ultraviolet cross-linking and improve the thickness and uniformity of the cross-linking of the material.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a cross-linked high-density polyethylene composite material, which is prepared from raw materials including the following components:

[0007]

[0008] Preferably, the density of the high-density polyethylene resin is ≥ 0.945 g / cm 3 .

[0009] Preferably, the organic peroxide cross-linking agent is tert-butyl peroxide.

[0010] Preferably, the auxiliary cross-linking agent includes one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate and triallyl cyanurate.

[0011] Preferably, the photosensitizer includes one or more of phenols, aromatic ketones and anilines.

[0012] Preferably, the other auxiliary agents include one or more of phenolic antioxidants and phosphite antioxidants.

[0013] The present invention also provides a method for preparing the cross-linked high-density polyethylene composite material described in the above technical solution, comprising the following steps:

[0014] (1) mixing a high-density polyethylene resin, an organic peroxide cross-linking agent, a co-cross-linking agent, a photosensitizer and other additives, and then melt-extruding the mixture to obtain a molten embryo; the molten embryo is a molten tube or a molten sheet;

[0015] (2) subjecting the molten embryo obtained in step (1) to a photothermal crosslinking reaction in a UV LED crosslinking furnace to obtain a crosslinked high-density polyethylene composite material.

[0016] Preferably, when the molten embryo in step (1) is a molten tube billet, when the melt extrusion device in step (1) is a parallel twin-screw extruder, the obtained molten embryo is a molten tube billet, and the temperature of the parallel twin-screw extruder includes seven temperature zones: the temperature of zone one is 90-110°C, the temperature of zone two is 135-145°C, the temperatures of zone three, zone four and zone five are independently 148-152°C, the temperature of zone six is ​​155-160°C, and the temperature of zone seven is 148-152°C.

[0017] Preferably, when the device for melt extrusion in step (1) is a single-screw extruder, the obtained molten embryo is a molten slab, and the temperature of the single-screw extruder includes three temperature zones: the temperature of zone one is 80-90°C; the temperature of zone two is 150-160°C; the temperature of zone three is 150-160°C.

[0018] Preferably, the temperature of the photothermal crosslinking reaction in step (2) is 270-350°C.

[0019] The present invention provides a cross-linked high-density polyethylene composite material, which is prepared from raw materials including the following components: 100 parts of high-density polyethylene, 0.1-0.3 parts of organic peroxide cross-linking agent, 0.3-0.7 parts of auxiliary cross-linking agent, 0.2-2 parts of photosensitizer and 0.3-0.5 parts of other auxiliary agents. The present invention adds a photosensitizer, which can absorb ultraviolet energy of a certain wavelength under ultraviolet light irradiation to stimulate the high-density polyethylene macromolecular chain to generate free radicals, and the auxiliary cross-linking agent can further induce the cross-linking reaction of free radicals between high-density polyethylene macromolecular chains; the heat rays generated during ultraviolet irradiation not only ensure that the cross-linkable embryo reaches the necessary temperature, but also have surplus heat energy, and the addition of an organic peroxide cross-linking agent can utilize the surplus heat energy to cause peroxide cross-linking; the presence of the organic peroxide cross-linking agent can not only make full use of the surplus heat energy of ultraviolet cross-linking, but also cause a cross-linking reaction in the deep material that ultraviolet light cannot penetrate, and the cross-linking thickness is thicker than that of a simple ultraviolet cross-linked high-density polyethylene material, and the overall cross-linking degree is higher and more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the process of preparing a cross-linked high-density polyethylene composite material in an embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention provides a cross-linked high-density polyethylene composite material, which is prepared from raw materials including the following components:

[0022]

[0023] By weight, the raw materials for preparing the cross-linked high-density polyethylene composite material of the present invention include 100 parts of high-density polyethylene resin. In the present invention, the density of the high-density polyethylene resin is preferably ≥ 0.945 g / cm 3 , more preferably 0.945 to 0.955 g / cm 3 The weight average molecular weight of the high-density polyethylene resin is preferably 120,000 to 220,000, more preferably 150,000 to 200,000. The present invention adopts the high-density polyethylene resin to make the prepared cross-linked high-density polyethylene composite material have better physical and chemical stability.

[0024] Based on 100 parts by weight of high-density polyethylene resin, the raw materials for preparing the cross-linked high-density polyethylene composite material of the present invention include 0.1 to 0.3 parts by weight of an organic peroxide crosslinking agent. In an embodiment of the present invention, the weight of the organic peroxide crosslinking agent may be 0.1, 0.2 or 0.3 parts. In the present invention, the organic peroxide crosslinking agent is preferably a tert-butyl peroxide peroxide. In an embodiment of the present invention, the model of the tert-butyl peroxide peroxide may be DYBP, double two five or DTBP. The present invention can utilize the excess heat energy of ultraviolet curing to cause peroxide crosslinking by adding an organic peroxide crosslinking agent; the presence of the organic peroxide crosslinking agent can not only utilize the excess heat energy of ultraviolet crosslinking, but also cause a crosslinking reaction inside the deep material that ultraviolet light cannot penetrate, so that the crosslinking thickness of the high-density polyethylene material is increased and the overall crosslinking degree is high and uniform.

[0025] Based on 100 parts by weight of high-density polyethylene resin, the raw materials for preparing the cross-linked high-density polyethylene composite material of the present invention include 0.3 to 0.7 parts by weight of a co-crosslinking agent, preferably 0.3 to 0.5 parts. In an embodiment of the present invention, the weight of the co-crosslinking agent may be 0.3 parts or 0.45 parts. In the present invention, the co-crosslinking agent preferably includes one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate and triallyl cyanurate. In an embodiment of the present invention, the model of the co-crosslinking agent may be TAIC, TMPTMA or TAC. The present invention can play a role in connecting molecular chains during ultraviolet crosslinking by adding a co-crosslinking agent, forming more crosslinking points, and generating a cross-linked polyethylene with a three-dimensional network structure.

[0026] Based on 100 parts by weight of high-density polyethylene resin, the raw materials for preparing the cross-linked high-density polyethylene composite material of the present invention include 0.2 to 2 parts by weight of a photosensitizer, preferably 0.2 to 0.5 parts. In an embodiment of the present invention, the weight of the photosensitizer may be 0.2 parts, 0.25 parts or 0.3 parts. In the present invention, the photosensitizer preferably includes one or more of phenols, aromatic ketones and anilines, more preferably aromatic ketones. In an embodiment of the present invention, the model of the aromatic ketone may be benzophenone. The present invention can generate free radicals by absorbing ultraviolet energy of a certain wavelength under ultraviolet light irradiation by adding a photosensitizer, thereby initiating a monomer cross-linking reaction.

[0027] Based on 100 parts by weight of high-density polyethylene, the raw materials for preparing the cross-linked high-density polyethylene composite material of the present invention include 0.3 to 0.5 parts by weight of other additives. In an embodiment of the present invention, the weight of the other additives may be 0.4 parts. In the present invention, the other additives preferably include one or more of phenolic antioxidants and phosphite antioxidants, more preferably phenolic antioxidants or phosphite antioxidants. In an embodiment of the present invention, the model of the phenolic antioxidant may be antioxidant 1076 or antioxidant 300, and the model of the phosphite antioxidant may be antioxidant 168. The present invention can inhibit or delay the oxidative degradation of high-density polyethylene by adding additives to the formula.

[0028] The present invention also provides a method for preparing the cross-linked high-density polyethylene composite material described in the above technical solution, comprising the following steps:

[0029] (1) mixing a high-density polyethylene resin, an organic peroxide cross-linking agent, a co-cross-linking agent, a photosensitizer and other additives, and then melt-extruding the mixture to obtain a molten embryo; the molten embryo is a molten tube or a molten sheet;

[0030] (2) subjecting the molten embryo obtained in step (1) to a photothermal crosslinking reaction in a UV LED crosslinking furnace to obtain a crosslinked high-density polyethylene composite material.

[0031] The invention mixes high-density polyethylene resin, organic peroxide cross-linking agent, auxiliary cross-linking agent, photosensitizer and other auxiliary agents, and then performs melt extrusion to obtain a melt embryo.

[0032] The present invention has no special restrictions on the method of mixing the high-density polyethylene resin, organic peroxide crosslinking agent, auxiliary crosslinking agent, photosensitizer and other auxiliary agents. Conventional mixing methods can be used to mix the components uniformly. In an embodiment of the present invention, the mixing device can be a high-speed mixer. The parameters of the high-speed mixer are: room temperature, and the mixing time is preferably 5 to 10 minutes.

[0033] In the present invention, the molten embryo is a molten tube or a molten slab.

[0034] In the present invention, when the melt extrusion device is preferably a parallel twin-screw extruder, the obtained melt embryo is a melt tube billet, and L / D is preferably 16-24. In the present invention, the temperature of the parallel twin-screw extruder preferably includes seven temperature zones: the temperature of the first zone is preferably 90-110°C, more preferably 100-110°C; the temperature of the second zone is preferably 135-145°C, more preferably 140-145°C; the temperature of the third zone is preferably 148-152°C, more preferably 150-152°C; the temperature of the fourth zone is preferably 148-152°C, more preferably 150-152°C; the temperature of the fifth zone is preferably 148-152°C, more preferably 150-152°C; the temperature of the sixth zone is preferably 155-160°C, more preferably 158-160°C; the temperature of the seventh zone is preferably 148-152°C, more preferably 150-152°C. The screw speed of the melt extrusion is preferably 30-80rpm, more preferably 50-70rpm.

[0035] The present invention performs melt extrusion under the above conditions, which can ensure that the molten embryo is plasticized uniformly and does not produce premature crosslinking.

[0036] In the present invention, when the melt extrusion device is preferably a single-screw extruder, the obtained molten embryo is a molten slab, D=30mm, L / D is preferably 18-24, preferably 20; the screw compression ratio is ≥3.8; the die head is preferably a fishtail die head. In the present invention, the screw speed of the single-screw extruder is preferably 40-80rpm, more preferably 60rpm. The temperature of the single-screw extruder preferably includes three temperature zones: the temperature of zone one is preferably 80-90°C, more preferably 85°C; the temperature of zone two is preferably 150-160°C, more preferably 155°C; the temperature of zone three is preferably 150-160°C, more preferably 155°C.

[0037] The present invention performs melt extrusion under the above conditions, which can avoid the problems of uneven molten embryo plastics, premature crosslinking, etc. caused by too high or too low temperature, and is conducive to obtaining a molten sheet embryo with uniform texture.

[0038] After obtaining the molten embryo, the present invention performs a photothermal crosslinking reaction on the molten embryo in a UV LED crosslinking furnace to obtain a crosslinked high-density polyethylene composite material.

[0039] In the present invention, the UV LED cross-linking furnace is preferably a horizontal ultraviolet cross-linking furnace, and the ultraviolet light source is preferably an ultraviolet light emitting diode.

[0040] In the present invention, when the molten embryo is a molten tube embryo, the UV LED cross-linking furnace can be the device disclosed in Chinese patent CN202222883880.4, and the light source power is preferably 10 to 18KW, more preferably 12 to 16KW. The present invention controls the light source power within the above range, which is more conducive to improving the reaction rate of the ultraviolet cross-linking reaction.

[0041] In the present invention, the temperature of the photothermal crosslinking reaction is preferably 270 to 350° C., and more preferably 300 to 350° C. The present invention is more conducive to promoting the photothermal crosslinking reaction to proceed fully at the above temperature.

[0042] In the present invention, when the molten embryo is a molten plate embryo, the UV LED cross-linking furnace can be a planar cross-linking furnace with two light sources in the upper and lower planes, and the power of each light source is preferably 500-1000W, more preferably 1000W; one side of the molten plate embryo can be independently controlled to be irradiated with ultraviolet light.

[0043] In the present invention, after the photothermal crosslinking reaction, shaping, cooling, inspection and collection are preferably performed in sequence to obtain a crosslinked high-density polyethylene composite material. The present invention has no special restrictions on the operation methods of shaping, cooling, inspection and collection, and conventional operation methods in the art can be used to obtain a crosslinked high-density polyethylene composite material with a size that meets the use requirements.

[0044] In the present invention, the process flow chart of the preparation method of the cross-linked high-density polyethylene composite material is preferably as follows Figure 1 As shown. The present invention mixes and extrude high-density polyethylene resin (HDPE), an organic peroxide crosslinking agent, a co-crosslinking agent, a photosensitizer and other additives, and then performs a photothermal crosslinking reaction, and then performs shaping, cooling, inspection and collection to obtain a crosslinked high-density polyethylene composite material. The method provided by the present invention is simple to operate and can obtain a crosslinked high-density polyethylene composite material with a high degree of crosslinking and good stability.

[0045] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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.

[0046] Example 1

[0047] A cross-linked high-density polyethylene composite material is prepared from the following raw materials:

[0048] Density: 0.952 g / cm 3, 100 parts of high-density polyethylene resin with a molecular weight of 180,000, 0.3 parts of organic peroxide crosslinking agent DTBP, 0.3 parts of auxiliary crosslinking agent TAC, 0.2 parts of photosensitizer benzophenone and 0.4 parts of other auxiliary antioxidant 300;

[0049] The preparation method of the cross-linked high-density polyethylene composite material is:

[0050] (1) After high-density polyethylene resin, organic peroxide crosslinking agent, auxiliary crosslinking agent, photosensitizer and other additives are uniformly mixed in a high-speed mixer, the tube embryo is melt-extruded on a twin-screw extruder, and the temperature of the melt extrusion is seven temperature zones: the temperature of zone 1 is 100°C, the temperature of zone 2 is 140°C, the temperatures of zone 3, zone 4 and zone 5 are independently 150°C, the temperature of zone 6 is 158°C, and the temperature of zone 7 is 150°C. (2) The molten tube embryo obtained in step (1) is passed through a horizontal ultraviolet crosslinking furnace, and a photothermal crosslinking reaction is carried out in a UV LED crosslinking furnace. The tube embryo linear speed is 16m / min, the ultraviolet power is 16KW, and the temperature in the furnace chamber is 320°C. Then, after sizing, cooling, inspection and collection, a DN16 cross-linked high-density polyethylene composite material is obtained, that is, a cross-linked high-density polyethylene tube with a thickness of 1.8mm. The test results are shown in Table 1.

[0051] Example 2

[0052] A cross-linked high-density polyethylene composite material is prepared from the following raw materials:

[0053] Density: 0.954 g / cm 3 , 100 parts of high-density polyethylene resin with a molecular weight of 200,000, 0.1 parts of organic peroxide crosslinking agent dichlorobenzene, 0.3 parts of auxiliary crosslinking agent TMPTMA, 0.25 parts of photosensitizer benzophenone and 1680.4 parts of other auxiliary antioxidants;

[0054] The preparation method of the cross-linked high-density polyethylene composite material is:

[0055] (1) After high-density polyethylene, organic peroxide crosslinking agent, auxiliary crosslinking agent, photosensitizer and other additives are uniformly mixed in a high-speed mixer, the tube blanks are formed by melt extrusion on a twin-screw extruder. The temperature of the melt extrusion is seven temperature zones: the temperature of zone 1 is 90° C., the temperature of zone 2 is 135° C., the temperatures of zone 3, zone 4 and zone 5 are independently 148° C., the temperature of zone 6 is 155° C., and the temperature of zone 7 is 148° C.

[0056] (2) The molten tube embryo obtained in the step (1) is passed through a horizontal ultraviolet cross-linking furnace, and a photothermal cross-linking reaction is carried out in a UV LED cross-linking furnace. The tube embryo linear speed is 10 m / min, the ultraviolet power is 10 kW, and the temperature in the furnace cavity is 300° C. Then, after sizing, cooling, inspection and collection, a DN16 cross-linked high-density polyethylene composite material is obtained, that is, a cross-linked high-density polyethylene tube with a thickness of 1.8 mm. The test results are shown in Table 1.

[0057] Example 3

[0058] A cross-linked high-density polyethylene composite material is prepared from the following raw materials:

[0059] Density: 0.954 g / cm 3 , 100 parts of high-density polyethylene resin with a molecular weight of 200,000, 0.2 parts of organic peroxide crosslinking agent DYBP, 0.45 parts of auxiliary crosslinking agent TAIC, 0.3 parts of photosensitizer benzophenone and 10760.4 parts of other auxiliary antioxidants;

[0060] The preparation method of the cross-linked high-density polyethylene composite material is:

[0061] (1) After high-density polyethylene, organic peroxide crosslinking agent, auxiliary crosslinking agent, photosensitizer and other additives are uniformly mixed in a high-speed mixer, the tube embryo is formed by melt extrusion on a twin-screw extruder, and the temperature of the melt extrusion is seven temperature zones: the temperature of zone 1 is 110° C., the temperature of zone 2 is 145° C., the temperatures of zone 3, zone 4 and zone 5 are independently 152° C., the temperature of zone 6 is 160° C., and the temperature of zone 7 is 152° C.

[0062] (2) The molten tube embryo obtained in the step (1) is passed through a horizontal ultraviolet cross-linking furnace, and a photothermal cross-linking reaction is carried out in a UV LED cross-linking furnace. The tube embryo linear speed is 20 m / min, the ultraviolet power is 18 kW, and the temperature in the furnace cavity is 350° C. Then, after sizing, cooling, inspection and collection, a DN16 cross-linked high-density polyethylene composite material is obtained, that is, a cross-linked high-density polyethylene tube with a thickness of 1.8 mm. The test results are shown in Table 1.

[0063] Example 4

[0064] A cross-linked high-density polyethylene composite material is prepared from the following raw materials:

[0065] Density: 0.952 g / cm 3 , 100 parts of high-density polyethylene resin with a molecular weight of 180,000, 0.3 parts of organic peroxide crosslinking agent DTBP, 0.3 parts of auxiliary crosslinking agent TAC, 0.2 parts of photosensitizer benzophenone and 3000.4 parts of other auxiliary antioxidants;

[0066] The preparation method of the cross-linked high-density polyethylene composite material is:

[0067] (1) After mixing high-density polyethylene resin, organic peroxide crosslinking agent, auxiliary crosslinking agent, photosensitizer and other additives in a high-speed mixer, the mixture is melt-extruded on a single-screw extruder. The temperature of the melt-extrusion is three temperature zones: the temperature of the first zone is 85° C., the temperature of the second zone is 155° C., and the temperature of the third zone is 155° C. The screw speed is 60 rpm to obtain a molten sheet embryo;

[0068] (2) The molten sheet obtained in step (1) is passed through an ultraviolet plane cross-linking furnace, and a photothermal cross-linking reaction is carried out in a UV LED cross-linking furnace. One side of the molten sheet is irradiated with ultraviolet light, and the ultraviolet power is 1000 W. The temperature in the furnace cavity is 290° C. After shaping, cooling, inspection and collection, a cross-linked high-density polyethylene composite material is obtained, that is, a cross-linked high-density polyethylene sheet with a thickness of 10 mm. The test results are shown in Table 1.

[0069] Comparative Example 1

[0070] A cross-linked high-density polyethylene composite material is prepared from the following raw materials:

[0071] Density: 0.954 g / cm 3 , 100 parts of high-density polyethylene resin with a molecular weight of 200,000, 0.1 parts of organic peroxide crosslinking agent DTBP, 0.2 parts of auxiliary crosslinking agent TAC, 0.1 parts of photosensitizer benzophenone and 10760.1 parts of other auxiliary antioxidants;

[0072] The preparation method of the cross-linked high-density polyethylene composite material is:

[0073] (1) After high-density polyethylene resin, organic peroxide crosslinking agent, auxiliary crosslinking agent, photosensitizer and other additives are uniformly mixed in a high-speed mixer, the tube blanks are formed by melt extrusion on a twin-screw extruder. The temperature of the melt extrusion is seven temperature zones: the temperature of zone 1 is 110° C., the temperature of zone 2 is 145° C., the temperatures of zone 3, zone 4 and zone 5 are independently 152° C., the temperature of zone 6 is 160° C., and the temperature of zone 7 is 152° C.

[0074] (2) The molten tube obtained in step (1) is passed through a UV horizontal cross-linking furnace, and a photothermal cross-linking reaction is carried out in a UV LED cross-linking furnace. The tube line speed is 16 m / min, the UV power is 16 kW, and the temperature in the furnace cavity is 320° C. Then, after sizing, cooling, inspection and collection, a DN16 cross-linked high-density polyethylene composite material is obtained with a thickness of 1.8 mm. The test results are shown in Table 1.

[0075] Comparative Example 2

[0076] A cross-linked high-density polyethylene composite material is prepared from the following raw materials:

[0077] Density: 0.954 g / cm 3 , 100 parts of high-density polyethylene resin with a molecular weight of 200,000, 0.37 parts of auxiliary cross-linking agent TAIC, 0.25 parts of photosensitizer benzophenone and 10760.4 parts of other auxiliary antioxidants;

[0078] The preparation method of the cross-linked high-density polyethylene composite material is:

[0079] (1) After high-density polyethylene resin, co-crosslinking agent, photosensitizer and other additives are uniformly mixed in a high-speed mixer, the mixture is melt-extruded on a twin-screw extruder. The temperature of the melt-extrusion is seven temperature zones: the temperature of zone 1 is 110° C., the temperature of zone 2 is 145° C., the temperatures of zones 3, 4 and 5 are independently 152° C., the temperature of zone 6 is 160° C., and the temperature of zone 7 is 152° C.

[0080] (2) The molten tube obtained in step (1) is passed through a UV horizontal cross-linking furnace, and a photothermal cross-linking reaction is carried out in a UV LED cross-linking furnace. The tube line speed is 16 m / min, the UV power is 16 kW, and the temperature in the furnace cavity is 320° C. Then, after sizing, cooling, inspection and collection, a DN16 cross-linked high-density polyethylene composite material is obtained with a thickness of 1.8 mm. The test results are shown in Table 1.

[0081] Comparative Example 3

[0082] A cross-linked high-density polyethylene composite material is prepared from the following raw materials:

[0083] Density: 0.952 g / cm 3 , 100 parts of high-density polyethylene resin with a molecular weight of 180,000, 0.3 parts of cross-linking agent TAC, 0.2 parts of photosensitizer benzophenone and 3000.2 parts of other auxiliary antioxidants;

[0084] The preparation method of the cross-linked high-density polyethylene composite material is:

[0085] (1) After mixing high-density polyethylene resin, co-crosslinking agent, photosensitizer and other additives in a high-speed mixer, the mixture is melt-extruded on a single-screw extruder. The temperature of the melt-extrusion is three temperature zones: the temperature of the first zone is 85° C., the temperature of the second zone is 155° C., and the temperature of the third zone is 155° C. The screw speed is 60 rpm to obtain a molten sheet embryo;

[0086] (2) The molten sheet obtained in step (1) is passed through a UV horizontal cross-linking furnace, and the obtained molten sheet is passed through a UV flat cross-linking furnace, and a photothermal cross-linking reaction is carried out in a UV LED cross-linking furnace. One side of the molten sheet is irradiated with UV light, the UV power is 1000 W, and the temperature in the furnace cavity is 290°C to obtain a cross-linked high-density polyethylene composite material. After shaping, cooling, inspection and collection, a cross-linked high-density polyethylene sheet with a thickness of 10 mm is obtained. The test results are shown in Table 1.

[0087] Test Case

[0088] The test results of the cross-linked high-density polyethylene composite materials prepared in Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1:

[0089] Table 1 Test results of cross-linked high-density polyethylene composite materials prepared in Examples 1 to 4 and Comparative Examples 1 to 3

[0090]

[0091]

[0092] It can be seen from the above results that the method provided by the present invention is simple to operate, and the cross-linked high-density polyethylene composite material prepared has a high and stable cross-linking degree, and the obtained pipe can pass the hydrostatic test (DIN 16892-2019), and the pipe has a good appearance; when the thickness of the plate is 10 mm, the cross-linking degree of the side facing away from the ultraviolet light can also reach 74%. From the results of Comparative Examples 1 and 2, it can be seen that when no organic peroxide cross-linking agent is added, or the amount of the organic peroxide cross-linking agent and the auxiliary cross-linking agent is not within the scope of the present invention, the cross-linking degree of the cross-linked high-density polyethylene composite material will be reduced, thereby causing the pipe to rupture. It can be seen from Comparative Example 3 that when the thickness of the plate is 10 mm, the cross-linking degree of the side facing away from the ultraviolet light can only reach 20%. This is because no organic peroxide cross-linking agent is added in Comparative Example 3, and only ultraviolet light cross-linking can be performed, so that the side facing the ultraviolet light has a higher cross-linking degree; and due to the limited penetration of ultraviolet light, when the plate is thicker, the cross-linking degree of the side facing away from the ultraviolet light is lower. The present invention simultaneously adds an organic peroxide crosslinking agent and an auxiliary crosslinking agent, and utilizes the auxiliary crosslinking agent to cause UV crosslinking of the raw materials; the presence of the organic peroxide crosslinking agent can not only utilize the surplus heat energy of UV crosslinking, but also can cause a crosslinking reaction on one side of the plate material that UV light cannot penetrate or inside the deep material, so that the outer surface layer of the high-density polyethylene material and the part that UV light cannot penetrate have a higher degree of crosslinking, thereby making the cross-linked high-density polyethylene composite material as a whole have a higher and uniform degree of crosslinking.

[0093] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A cross-linked high-density polyethylene composite material, characterized in that: It is prepared from raw materials including the following components:

2. The cross-linked high-density polyethylene composite material according to claim 1, characterized in that: The density of the high-density polyethylene resin is ≥0.945 g / cm 3 .

3. The cross-linked high-density polyethylene composite material according to claim 1, characterized in that: The organic peroxide cross-linking agent is tert-butyl peroxide.

4. The cross-linked high-density polyethylene composite material according to claim 1, characterized in that: The auxiliary cross-linking agent includes one or more of triallyl isocyanurate, trimethylolpropane trimethacrylate and triallyl cyanurate.

5. The cross-linked high-density polyethylene composite material according to claim 1, characterized in that: The photosensitizer includes one or more of phenols, aromatic ketones and anilines.

6. The cross-linked high-density polyethylene composite material according to claim 1, characterized in that: The other auxiliary agents include one or more of phenolic antioxidants and phosphite antioxidants.

7. The method for preparing the cross-linked high-density polyethylene composite material according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) mixing a high-density polyethylene resin, an organic peroxide cross-linking agent, a co-cross-linking agent, a photosensitizer and other additives, and then melt-extruding the mixture to obtain a molten embryo; the molten embryo is a molten tube or a molten sheet; (2) subjecting the molten embryo obtained in step (1) to a photothermal crosslinking reaction in a UV LED crosslinking furnace to obtain a crosslinked high-density polyethylene composite material.

8. The preparation method according to claim 7, characterized in that: When the device for melt extrusion in step (1) is a parallel twin-screw extruder, the obtained molten embryo is a molten tube billet, and the temperature of the parallel twin-screw extruder includes seven temperature zones: the temperature of zone one is 90-110°C, the temperature of zone two is 135-145°C, the temperatures of zone three, zone four and zone five are independently 148-152°C, the temperature of zone six is ​​155-160°C, and the temperature of zone seven is 148-152°C.

9. The preparation method according to claim 7, characterized in that: When the device for melt extrusion in step (1) is a single-screw extruder, the obtained molten embryo is a molten slab, and the temperature of the single-screw extruder includes three temperature zones: the temperature of zone one is 80-90°C; the temperature of zone two is 150-160°C; and the temperature of zone three is 150-160°C.

10. The preparation method according to claim 7, characterized in that: The temperature of the photothermal crosslinking reaction in step (2) is 270-350°C.

Images