A black cycloolefin copolymer and its preparation method and application

Abstract

The invention provides a black cycloolefin copolymer and a preparation method and application thereof, belonging to the technical field of polymer preparation. The preparation method firstly wets black powder and an auxiliary agent containing an antioxidant by using a solvent, then mixes the obtained wetted material with COC particles and heats them, so that the black powder and the antioxidant can be evenly coated on the surface of the COC particles, effectively improving the uniformity of the combination of the COC particles and the black powder, and further uses nitrogen vaporized from liquid nitrogen to evenly cool the inside of the particles, avoiding the problem of uneven cooling caused by external circulating water, further improving the uniform combination of the black powder and the COC particles, avoiding thermal aging and shear aging of the particles in a melt granulation process, so that the prepared black cycloolefin copolymer has excellent mechanical properties and color uniformity, and effectively avoids the problems of dust flying and injection molding machine pollution caused by conventional mixing, and is suitable for preparing curved reflectors of HUDs.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer preparation, and in particular relates to a black cycloolefin copolymer and a preparation method and application thereof. Background Art

[0002] There are several main reasons for coloring plastics: first, to beautify the product and increase the price of the product; second, to provide concealed protection for the product, which not only refers to light protection for food and medical treatment, but also includes light interference of injection molded samples of the product's original color; third, to give the material certain properties or functions.

[0003] The black modification of HUD curved reflector materials is mainly based on the purpose of light concealing effect of the product; the natural color of COC suitable for reflector injection molding is transparent. The application of transparent materials on reflectors will cause light interference, so the material needs to be changed in color.

[0004] At present, there are also transparent materials on the market that are coated with black films before use, but if they are bumped or worn during use, the shielding effect of the covering black film will be invalid. Another method is to modify the COC particles to black. The main methods for modifying the blackness of the resin are masterbatch / color powder granulation modification and external masterbatch modification. For the molding end, masterbatch / color powder granulation modification is more advantageous than external masterbatch injection molding, and the color uniformity of the product is better; however, for material properties, external masterbatch injection molding is better than masterbatch / color powder granulation modification. External masterbatch injection molding can reduce the thermal history of the resin, thereby reducing the resin performance attenuation caused by heat and shear. Although the additional addition of additives can reduce the material performance attenuation, there is a risk of additive precipitation, and the process control of masterbatch / color powder external injection molding is complex. At the same time, masterbatch external injection molding has the problem of color difference of the injection molded parts, and external mixing of color powder will make the injection molding machine difficult to clean and bring dust to the environment.

[0005] In addition, with the continuous deepening of intelligence and humanization in the modern automobile industry, HUD curved reflectors have become a relatively new direction for the development of automotive parts in the past two years. At the same time, the demand for the development and application of large-size HUD curved reflectors is becoming more and more urgent.

[0006] Most of the HUD curved reflectors disclosed in the prior art use a glass thermal bending process. For example, CN115626764A discloses a vehicle-mounted HUD curved reflector and its preparation process, in which the substrate material of the curved reflector is glass; however, due to the density of glass (2.4-2.8 g / cm 3) has a higher density than plastic, so the weight of glass is greater for the same volume. At the same time, the inherent brittleness of glass itself also limits its application in HUD curved reflectors. For another example, CN117608014A discloses a curved reflector for HUD, its manufacturing process and application, and mentions that during the use of the free-form reflector made of PC material, the reflector film may be damaged due to the backflow of sunlight. It is speculated that the possible cause of the damage to the film layer is due to the poor dimensional stability of the PC material. In addition, the temperature difference inside the car is large, especially in summer. When the car is in use due to air conditioning, the general temperature is 20~30℃. If it is exposed to the sun, the backflow temperature of sunlight can reach over 100℃. In this process, the change in the size of the PC material is very likely to cause damage to the film layer.

[0007] Therefore, in view of the above technical problems, it is urgent to develop a method for preparing a black cycloolefin copolymer with high color uniformity and excellent mechanical properties. Summary of the invention

[0008] In view of the deficiencies in the prior art, the object of the present invention is to provide a black cyclic olefin copolymer and a preparation method and application thereof. The preparation method can effectively avoid thermal aging and shear aging of particles in the melt granulation process, avoid the influence of thermal history on material properties, and avoid the problems of large color difference of injection molded parts in external masterbatch injection molding, and dust flying and injection molding machine pollution caused by external color powder. The obtained black cyclic olefin copolymer has excellent color uniformity and mechanical properties, and is suitable for preparing curved reflectors for HUD.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a black cycloolefin copolymer, the preparation method comprising the following steps:

[0011] (1) Wetting the black powder and the additives including the antioxidant with a solvent to obtain a wetted material;

[0012] (2) mixing the wetted material obtained in step (1) with the cycloolefin copolymer particles, evacuating the mixture and heating the mixture to remove the solvent, then stopping the evacuation and introducing nitrogen vaporized from liquid nitrogen to cool the mixture, discharging the mixture, and obtaining black particles;

[0013] (3) Injection molding the black particles obtained in step (2) to obtain the black cycloolefin copolymer.

[0014] The invention provides a method for preparing a black cycloolefin copolymer. First, a solvent is used to wet black powder and an auxiliary agent containing an antioxidant to obtain a wetted material; then the obtained wetted material is mixed with cycloolefin copolymer particles (COC particles); during the mixing process, the wetted material is adsorbed on the surface of the COC particles; then vacuuming and heating are performed, and the heating temperature is controlled, so that not only the solvent can be removed, but also the antioxidant can be melted; the melted antioxidant can play the role of an adhesive, and can evenly and firmly wrap the black powder on the surface of the COC particles, thereby effectively improving the uniformity of the combination of the black powder and COC; then, the vacuuming is stopped and nitrogen gas vaporized from liquid nitrogen is introduced to cool down the temperature to obtain black particles; the method of introducing nitrogen gas vaporized from liquid nitrogen to cool down the temperature can cool down the inside of the particles. temperature, avoiding the uneven temperature of the external circulating water cooling, thereby further improving the uniform combination of the black powder and the COC particles; finally, the obtained black particles are injection molded to obtain the black cyclic olefin copolymer; the preparation method uniformly coats the COC particles with black powder and cools them with nitrogen vaporized from liquid nitrogen, thereby avoiding the thermal aging and shear aging of the particles in the melt granulation process, reducing the influence of thermal history on material properties, and solving the dusting problem of injection molding of externally mixed color powder and the color difference of injection molded parts caused by externally mixed color masterbatch. In addition, it can also avoid the problems of cumbersome process control of the injection molding process and unstable color of the parts, and finally obtains a black cyclic olefin copolymer with excellent mechanical properties and color uniformity, which is suitable for HUD curved reflectors.

[0015] It should be noted that the wetting material obtained in step (1) of the present invention refers to the black powder and the auxiliary agent containing the antioxidant wetted with the solvent attached to the surface.

[0016] Preferably, based on 100 parts by weight of the cycloolefin copolymer particles, the amount of the solvent is 1.5-8 parts by weight (for example, 1.5 parts by weight, 2 parts by weight, 2.5 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight or 8 parts by weight, etc.), the amount of black powder is 0.01-0.1 parts by weight (for example, 0.01 parts by weight, 0.02 parts by weight, 0.03 parts by weight, 0.04 parts by weight, 0.05 parts by weight, 0.06 parts by weight, 0.07 parts by weight, 0.08 parts by weight, 0.09 parts by weight or 0.1 parts by weight, etc.), and the amount of the antioxidant is 1-3 parts by weight (for example, 1 part by weight, 1.2 parts by weight, 1.4 parts by weight, 1.6 parts by weight, 1.8 parts by weight, 2 parts by weight, 2.2 parts by weight, 2.4 parts by weight, 2.6 parts by weight, 2.8 parts by weight or 3 parts by weight, etc.).

[0017] In the present invention, if the amount of solvent used exceeds the above-defined range, the subsequent heating to remove the solvent will take too long, resulting in a greater impact of thermal history on material properties and affecting the appearance of COC particles.

[0018] Preferably, the glass transition temperature (Tg) of the cycloolefin copolymer particles is 135-150°C, for example, 135°C, 137°C, 139°C, 141°C, 143°C, 145°C, 147°C, 149°C or 150°C.

[0019] Preferably, the melt index of the cycloolefin copolymer particles is 8 to 45 g / 10 min, for example, 8 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, 25 g / 10 min, 30 g / 10 min, 35 g / 10 min, 40 g / 10 min or 45 g / 10 min, etc.; the test temperature of the melt index is 260 ° C and the load is 2.16 kg.

[0020] Preferably, the D of the cycloolefin copolymer particles is 50 The particle size is 1 to 5 mm, for example, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0021] Preferably, the solvent includes any one of water, methanol, ethanol or butanol, or a combination of at least two of them.

[0022] Preferably, the black powder includes any one of carbon black, black titanium oxide or cobalt black, or a combination of at least two of them.

[0023] Preferably, the carbon black comprises pigment carbon black.

[0024] Preferably, the pigment carbon black includes but is not limited to high pigment trough black (particle size is 10-14 nm), medium pigment trough black (particle size is 15-27 nm), medium pigment furnace black (particle size is 17-27 nm) and low pigment furnace black (particle size is 28-70 nm).

[0025] Preferably, the melting point of the antioxidant is ≤150°C.

[0026] In the present invention, there is no special requirement for the type of the antioxidant, as long as its melting point meets the requirements. Exemplarily, the antioxidant includes any one of antioxidant 1010, antioxidant 1076, distearyl thiodipropionate, antioxidant 2246 or antioxidant 264, or a combination of at least two of them.

[0027] The auxiliary agent also includes a dispersant. Based on 100 parts by weight of the cycloolefin copolymer particles, the amount of the dispersant is 0.5 to 1 part by weight, for example, 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight or 1 part by weight.

[0028] In the present invention, there is no special requirement for the type of the dispersant. A commonly used dispersant in the art can be selected. For example, the dispersant includes any one of dispersant HK-236, dispersant TL-J181, PE wax powder, dispersant F440B or vinylbenzene sulfonic acid, or a combination of at least two thereof.

[0029] Preferably, the mixing in step (2) specifically comprises: placing the wetted material obtained in step (1) and the cycloolefin copolymer particles into a vacuum high mixer, and stirring at a rotation speed of 100-300 rpm (for example, 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm or 300 rpm, etc.) for 3-5 min (for example, 3 min, 3.2 min, 3.4 min, 3.6 min, 3.8 min, 4 min, 4.2 min, 4.4 min, 4.6 min, 4.8 min or 5 min, etc.) to complete the mixing.

[0030] Preferably, the vacuum degree of the system after the vacuuming in step (2) is 0.08-0.1 MPa, for example, 0.08 MPa, 0.085 MPa, 0.09 MPa, 0.095 MPa or 0.1 MPa.

[0031] Preferably, the temperature of the system after heating to remove the solvent in step (2) is lower than the glass transition temperature of the cycloolefin copolymer particles and is at least 5°C higher than the melting point of the antioxidant, for example, 5°C, 6°C, 7°C, 8°C, 9°C or 10°C; meaning that the temperature of heating to remove the solvent is lower than the Tg of the COC particles, thereby preventing the COC particles from reaching the softening temperature and causing adhesion and agglomeration, but is at least 5°C higher than the melting point of the antioxidant, thereby allowing the antioxidant to melt and act as an adhesive.

[0032] Preferably, after stopping the vacuuming in step (2), the process further comprises stirring the mixture at a speed of 80 to 300 rpm (for example, 80 rpm, 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 250 rpm or 300 rpm, etc.) for 5 to 15 min (for example, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min or 15 min, etc.).

[0033] Preferably, in step (2), the temperature of the system after cooling by introducing vaporized nitrogen from liquid nitrogen is at least 5°C lower than the melting point of the antioxidant, for example, 5°C, 6°C, 7°C, 8°C, 9°C or 10°C, etc.; meaning that the temperature after cooling by introducing liquid nitrogen is at least 5°C lower than the melting point of the antioxidant, in order to solidify the molten antioxidant.

[0034] Preferably, the flow rate of the nitrogen gas vaporized by liquid nitrogen in step (2) is 20-100 L / min, for example, 20 L / min, 30 L / min, 40 L / min, 50 L / min, 60 L / min, 70 L / min, 80 L / min, 90 L / min or 100 L / min.

[0035] Preferably, the amount of black particles falling off in step (2) is less than 1 ppm, for example, 0.9 ppm, 0.8 ppm, 0.7 ppm, 0.6 ppm, 0.5 ppm or 0.1 ppm.

[0036] The "powder loss of black particles" refers to the percentage reduction in the mass of the black particles obtained after discharging compared with the total mass of the wetting material and the cycloolefin copolymer particles before mixing. The testing method includes: first weighing the wetting material and the cycloolefin copolymer particles before mixing to obtain the total mass, then sieving the prepared black particles with a 30-mesh sieve, weighing the powder that falls through the sieve, and calculating the ratio of the mass of the powder that falls through the sieve to the total mass of the wetting material and the cycloolefin copolymer particles before mixing.

[0037] Preferably, the temperature of the injection molding in step (3) is 250-285°C, for example, 250°C, 255°C, 260°C, 265°C, 270°C, 275°C, 280°C or 285°C.

[0038] Preferably, the holding pressure of the injection molding in step (3) is 40-80 MPa, for example, 40 MPa, 45 MPa, 50 MPa, 55 MPa, 60 MPa, 65 MPa, 70 MPa, 75 MPa or 80 MPa.

[0039] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0040] (1) 0.01-0.1 parts by weight of black powder, 1-3 parts by weight of antioxidant and 0.5-1 parts by weight of dispersant are wetted with 1.5-8 parts by weight of solvent to obtain a wetted material;

[0041] (2) placing 100 parts by weight of the wetted material obtained in step (1) and the cycloolefin copolymer particles into a vacuum high mixer, stirring at a speed of 100-300 rpm for 3-5 min, evacuating the system until the vacuum degree of the system is 0.08-0.1 MPa, heating the system until the temperature is lower than the glass transition temperature of the cycloolefin copolymer particles and higher than the melting point of the antioxidant by more than 5° C., then stopping evacuating the system, continuing stirring at a speed of 80-300 rpm for 5-15 min, then introducing nitrogen vaporized from liquid nitrogen at a flow rate of 20-100 L / min for cooling, discharging the material, until the temperature of the system is more than 5° C. lower than the melting point of the antioxidant, to obtain black particles;

[0042] (3) The black particles obtained in step (2) are injection molded at a temperature of 250-285° C. and a holding pressure of 40-80 MPa to obtain the black cycloolefin copolymer.

[0043] In a second aspect, the present invention provides a black cycloolefin copolymer, wherein the black cycloolefin copolymer is prepared by the preparation method described in the first aspect.

[0044] In a third aspect, the present invention provides a use of the black cyclic olefin copolymer described in the second aspect in the preparation of a HUD curved reflector.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The preparation method of the black cycloolefin copolymer provided by the present invention firstly wets black powder and an auxiliary agent containing an antioxidant by using a solvent, then mixes the wetted material and COC particles and heats them, so that the black powder and the antioxidant can be evenly coated on the surface of the COC particles, effectively improving the uniformity of the combination of the COC particles and the black powder, and further uses nitrogen vaporized from liquid nitrogen to evenly cool the inside of the particles, avoiding the problem of uneven cooling caused by external circulating water, further improving the uniform combination of the black powder and the COC particles, avoiding thermal aging and shear aging of the particles in the melt granulation process, so that the prepared black cycloolefin copolymer has excellent mechanical properties and color uniformity, and also effectively avoids the dust flying and injection molding machine pollution problems caused by conventional mixing, and is suitable for preparing curved reflectors of HUD. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a schematic diagram of the structure of the vacuum high mixer in Example 1;

[0048] Among them, 1-the first ball valve, 2-the second ball valve, 3-the third ball valve, 4-the vacuum port, 5-the vaporizer, 6-the liquid nitrogen sealing port, and 7-the discharge port. DETAILED DESCRIPTION

[0049] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0050] Unless otherwise specified, the raw materials involved in the following specific embodiments are all conventional materials in the art and can be purchased commercially;

[0051] In particular, the COC particles used in the following specific embodiments are purchased from Zhejiang Tuoxie Optical New Materials Co., Ltd., with a Tg of 145°C and a D 50 The particle size is 2 mm and the melt index is 9 g / 10 min (260°C / 2.16 kg).

[0052] Example 1

[0053] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0054] (1) 2 kg of 15% methanol solution and 0.02 kg of high-pigment tank black (particle size of 10-14 nm) were mixed, and then 0.5 kg of PE wax powder and 1.5 kg of antioxidant 1010 (melting point of about 116°C) were added and mixed, so that the 15% methanol solution wetted the high-pigment tank black, PE wax powder and antioxidant 1010 to obtain a wetted material;

[0055] (2) The wetted material obtained in step (1) and 100 kg of COC particles are placed in a 300 L vacuum high mixer. The schematic diagram of the vacuum high mixer is shown in FIG. Figure 1 As shown, the cover of the high mixer, the first ball valve 1, the second ball valve 2 and the third ball valve 3 are closed, and stirring is started. The stirring speed is set to 100 rpm and the stirring time is 5 minutes to fully mix the COC particles and the wetting material. Then, the heating mode of the vacuum high mixer is turned on, the vacuum pump is turned on, and the second ball valve 2 of the vacuum port 4 is opened. Vacuum the system to a vacuum degree of 0.1 MPa, and heat until the temperature reaches 130°C. Stop heating, close the second ball valve 2 of the vacuum port 4, and disconnect the vacuum pump. , turn off the vacuum pump, stir for 10 minutes at a stirring speed of 100 rpm, then slowly open the third ball valve 3, and open the vaporizer 5, and introduce nitrogen vaporized by the vaporizer 5 from the liquid nitrogen sealing barrel 6, the flow rate of nitrogen vaporized by liquid nitrogen is 50 L / min, after the vacuum degree of the system drops to 0 MPa, open the first ball valve 1 to exhaust, after the system temperature is reduced to 100 ° C, stop stirring, open the discharge port 7 to discharge, and obtain black particles, the powder loss of black particles is <1ppm;

[0056] (3) The black particles obtained in step (2) are injection molded at a temperature of 270° C. and a holding pressure of 50 MPa to obtain the black cycloolefin copolymer.

[0057] Example 2

[0058] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0059] (1) 4.5 kg of 15% methanol solution and 0.1 kg of high-pigment tank black (particle size of 10-14 nm) were mixed, and then 1 kg of PE wax powder and 3 kg of antioxidant 1076 (melting point of about 51°C) were added and mixed, so that the 15% methanol solution wetted the high-pigment tank black, PE wax powder and antioxidant 1076 to obtain a wetted material;

[0060] (2) The wetted material obtained in step (1) and 100 kg of COC particles were placed in a 300 L vacuum high mixer. The structure of the vacuum high mixer was the same as that of Example 1. The cover, the first ball valve, the second ball valve and the third ball valve of the vacuum high mixer were closed, and stirring was started. The stirring speed was set to 150 rpm and the stirring time was 5 min. The COC particles and the wetted material were fully mixed. Then, the heating mode of the vacuum high mixer was turned on, the vacuum pump was turned on, and the vacuum port was opened. The system was evacuated to a vacuum degree of 0.09 MPa, and the system was heated until the temperature reached 80° C. The heating was stopped and the system was turned off. Close the vacuum port, disconnect the vacuum pump, turn off the vacuum pump, stir for 10 minutes at a stirring speed of 200 rpm, then slowly open the third ball valve, and open the vaporizer, and introduce nitrogen vaporized by the vaporizer from the liquid nitrogen sealed barrel. The flow rate of nitrogen vaporized by liquid nitrogen is 50 L / min. After the vacuum degree of the system drops to 0 MPa, open the first ball valve to exhaust, lower the system temperature to 40°C, stop stirring, open the discharge port to discharge, and obtain black particles. The powder loss of black particles is <1 ppm;

[0061] (3) The black particles obtained in step (2) are injection molded at a temperature of 260° C. and a holding pressure of 70 MPa to obtain the black cycloolefin copolymer.

[0062] Example 3

[0063] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0064] (1) 4 kg of 15% methanol solution and 0.05 kg of high-pigment tank black (particle size of 10-14 nm) are mixed, and then 0.5 kg of vinylbenzene sulfonic acid and 3 kg of antioxidant 1076 (melting point of about 51°C) are added and mixed, so that the methanol solution wets the high-pigment tank black, vinylbenzene sulfonic acid and antioxidant 1076 to obtain a wetted material;

[0065] (2) The wetted material obtained in step (1) and 100 kg of COC particles are placed in a 300 L vacuum high mixer. The structure of the vacuum high mixer is the same as that of Example 1. The cover, the first ball valve, the second ball valve and the third ball valve of the vacuum high mixer are closed, and stirring is started. The stirring speed is set to 300 rpm and the stirring time is 5 min. The COC particles and the wetted material are fully mixed. Then, the heating mode of the vacuum high mixer is turned on, the vacuum pump is turned on, and the vacuum port is opened. The system is evacuated to a vacuum degree of 0.09 MPa, and the system is heated until the temperature reaches 80° C. The heating is stopped and the system is turned off. Close the vacuum port, disconnect the vacuum pump, turn off the vacuum pump, stir for 10 minutes at a stirring speed of 100 rpm, then slowly open the third ball valve, and open the vaporizer, and introduce nitrogen vaporized by the vaporizer from the liquid nitrogen sealed barrel. The flow rate of nitrogen vaporized by liquid nitrogen is 50 L / min. After the vacuum degree of the system drops to 0 MPa, open the first ball valve to exhaust, lower the system temperature to 30°C, stop stirring, open the discharge port to discharge, and obtain black particles. The powder loss of black particles is <1 ppm;

[0066] (3) The black particles obtained in step (2) are injection molded at a temperature of 280° C. and a holding pressure of 45 MPa to obtain the black cycloolefin copolymer.

[0067] Example 4

[0068] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0069] (1) Mix 2.5 kg of 15% methanol solution and 0.05 kg of low-pigment furnace black (particle size 28-70 nm), then add 0.5 kg of dispersant HK-236 and 1.5 kg of antioxidant 1076 (melting point is about 51°C) and mix them, so that the 15% methanol solution wets the low-pigment furnace black, dispersant HK-236 and antioxidant 1076 to obtain a wetted material;

[0070] (2) The wetted material obtained in step (1) and 100 kg of COC particles are placed in a 300 L vacuum high mixer. The structure of the vacuum high mixer is the same as that of Example 1. The cover, the first ball valve, the second ball valve and the third ball valve of the vacuum high mixer are closed, and stirring is started. The stirring speed is set to 300 rpm and the stirring time is 5 min. The COC particles and the wetted material are fully mixed. Then, the heating mode of the vacuum high mixer is turned on, the vacuum pump is turned on, and the vacuum port is opened. The system is evacuated to a vacuum degree of 0.08 MPa, and the system is heated until the temperature reaches 65° C. The heating is stopped and the system is closed. The vacuum port is opened, the vacuum pump is disconnected, the vacuum pump is turned off, and the stirring speed is 100 rpm for 10 minutes, and then the third ball valve is slowly opened, and the vaporizer is opened, and the nitrogen vaporized by the vaporizer is introduced from the liquid nitrogen sealed barrel, and the flow rate of the nitrogen vaporized by the liquid nitrogen is 50 L / min. After the vacuum degree of the system drops to 0 MPa, the first ball valve is opened for exhaust, and after the system temperature is lowered to 35°C, the stirring is stopped, and the discharge port 8 is opened for discharge to obtain black particles, and the powder loss of the black particles is <1ppm;

[0071] (3) The black particles obtained in step (2) are injection molded at a temperature of 260° C. and a holding pressure of 50 MPa to obtain the black cycloolefin copolymer.

[0072] Example 5

[0073] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0074] (1) 2 kg of 15% methanol solution and 0.05 kg of high-pigment tank black (particle size of 10-14 nm) were mixed, and then 0.5 kg of PE wax powder and 1.5 kg of antioxidant 1076 (melting point of about 51°C) were added and mixed, so that the 15% methanol solution wetted the high-pigment tank black, PE wax powder and antioxidant 1076 to obtain a wetted material;

[0075] (2) The wetted material obtained in step (1) and 100 kg of COC particles are placed in a 300 L vacuum high mixer. The structure of the vacuum high mixer is the same as that of Example 1. The cover, the first ball valve, the second ball valve and the third ball valve of the vacuum high mixer are closed, and stirring is started. The stirring speed is set to 100 rpm and the stirring time is 5 min. The COC particles and the wetted material are fully mixed. Then, the heating mode of the vacuum high mixer is turned on, the vacuum pump is turned on, and the vacuum port is opened. The system is evacuated to a vacuum degree of 0.1 MPa, and the system is heated until the temperature reaches 65° C. The heating is stopped and the system is closed. The vacuum port was opened, the vacuum pump was disconnected, the vacuum pump was turned off, and the stirring speed was 150 rpm for 10 min, and then the third ball valve was slowly opened, and the vaporizer was turned on, and the nitrogen vaporized by the vaporizer was introduced from the liquid nitrogen sealed barrel, and the flow rate of the nitrogen vaporized by the liquid nitrogen was 20 L / min. After the vacuum degree of the system dropped to 0 MPa, the first ball valve was opened for exhaust, and after the system temperature was lowered to 40 ° C, the stirring was stopped, and the discharge port was opened for discharge to obtain black particles, and the powder loss of the black particles was <1 ppm;

[0076] (3) The black particles obtained in step (2) are injection molded at a temperature of 260° C. and a holding pressure of 50 MPa to obtain the black cycloolefin copolymer.

[0077] Example 6

[0078] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0079] (1) 2.6 kg of 15% methanol solution and 0.05 kg of medium pigment furnace black (particle size of 17-27 nm) are mixed, and then 0.5 kg of dispersant F440B and 2 kg of antioxidant 1076 (melting point of about 51°C) are added and mixed, so that the methanol solution wets the medium pigment furnace black, dispersant F440B and antioxidant 1076 to obtain a wetted material;

[0080] (2) The wetted material obtained in step (1) and 100 kg of COC particles were placed in a 300 L vacuum high mixer. The structure of the vacuum high mixer was the same as that of Example 1. The cover, the first ball valve, the second ball valve and the third ball valve of the vacuum high mixer were closed, and stirring was started. The stirring speed was set to 300 rpm and the stirring time was 5 min. The COC particles and the wetted material were fully mixed. Then, the heating mode of the vacuum high mixer was turned on, the vacuum pump was turned on, and the vacuum port was opened. The system was evacuated to a vacuum degree of 0.1 MPa, and the system was heated until the temperature reached 138° C. The heating was stopped and the system was closed. The vacuum port was opened, the vacuum pump was disconnected, the vacuum pump was turned off, and the stirring speed was 300 rpm for 10 min, and then the third ball valve was slowly opened, and the vaporizer was turned on, and the nitrogen vaporized by the vaporizer was introduced from the liquid nitrogen sealed barrel, and the flow rate of the nitrogen vaporized by the liquid nitrogen was 100 L / min. After the vacuum degree of the system dropped to 0 MPa, the first ball valve was opened for exhaust, and after the system temperature was lowered to 40°C, the stirring was stopped, and the discharge port was opened for discharge to obtain black particles, and the powder loss of the black particles was <1 ppm;

[0081] (3) The black particles obtained in step (2) are injection molded at a temperature of 260° C. and a holding pressure of 50 MPa to obtain the black cycloolefin copolymer.

[0082] Example 7

[0083] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0084] (1) 2.6 kg of 10% ethanol solution and 0.05 kg of high-pigment furnace black (particle size of 10-14 nm) were mixed, and then 0.5 kg of dispersant F440B and 2 kg of antioxidant 264 (melting point of about 70°C) were added and mixed, so that the methanol solution wetted the medium-pigment furnace black, dispersant F440B and antioxidant 264 to obtain a wetted material;

[0085] (2) The wetted material obtained in step (1) and 100 kg of COC particles are placed in a 300 L vacuum high mixer. The structure of the vacuum high mixer is the same as that of Example 1. The cover, the first ball valve, the second ball valve and the third ball valve of the vacuum high mixer are closed, and stirring is started. The stirring speed is set to 200 rpm and the stirring time is 5 min. The COC particles and the wetted material are fully mixed. Then, the heating mode of the vacuum high mixer is turned on, the vacuum pump is turned on, and the vacuum port is opened. The system is evacuated to a vacuum degree of 0.09 MPa, and the system is heated until the temperature reaches 85° C. The heating is stopped and the system is closed. The vacuum port is opened, the vacuum pump is disconnected, the vacuum pump is turned off, and the stirring speed is 200 rpm for 10 minutes, and then the third ball valve is slowly opened, and the vaporizer is opened, and the nitrogen vaporized by the vaporizer is introduced from the liquid nitrogen sealed barrel, and the flow rate of the nitrogen vaporized by the liquid nitrogen is 30L / min. After the vacuum degree of the system drops to 0MPa, the first ball valve is opened for exhaust, and after the system temperature is lowered to 55°C, the stirring is stopped, and the discharge port 8 is opened for discharge to obtain black particles, and the powder loss of the black particles is <1ppm;

[0086] (3) The black particles obtained in step (2) are injection molded at a temperature of 260° C. and a holding pressure of 50 MPa to obtain the black cycloolefin copolymer.

[0087] Example 8

[0088] A method for preparing a black cycloolefin copolymer comprises the following steps:

[0089] (1) 2 kg of 10% ethanol solution and 0.05 kg of medium pigment furnace black (particle size of 17-27 nm) are mixed, and then 0.5 kg of dispersant F440B and 2 kg of antioxidant 264 (melting point of about 70°C) are added and mixed, so that the methanol solution wets the medium pigment furnace black, dispersant F440B and antioxidant 264 to obtain a wetted material;

[0090] (2) The wetted material obtained in step (1) and 100 kg of COC particles are placed in a 300 L vacuum high mixer. The structure of the vacuum high mixer is the same as that of Example 1. The cover, the first ball valve, the second ball valve and the third ball valve of the vacuum high mixer are closed, and stirring is started. The stirring speed is set to 200 rpm and the stirring time is 5 min. The COC particles and the wetted material are fully mixed. Then, the heating mode of the vacuum high mixer is turned on, the vacuum pump is turned on, and the vacuum port is opened. The system is evacuated to a vacuum degree of 0.1 MPa, and the system is heated until the temperature reaches 85° C. The heating is stopped and the vacuum is turned off. The vacuum pump was disconnected and turned off. The mixture was stirred at a stirring speed of 200 rpm for 10 min, and then the third ball valve was slowly opened, and the vaporizer was turned on. Nitrogen vaporized by the vaporizer was introduced from the liquid nitrogen sealed barrel at a flow rate of 40 L / min. After the vacuum degree of the system dropped to 0 MPa, the first ball valve was opened for exhaust, and after the system temperature was lowered to 55°C, the stirring was stopped, and the discharge port 8 was opened for discharge to obtain black particles. The powder loss of the black particles was <1 ppm.

[0091] (3) The black particles obtained in step (2) are injection molded at a temperature of 250° C. and a holding pressure of 55 MPa to obtain the black cycloolefin copolymer.

[0092] Embodiment 9-10

[0093] A method for preparing a black cycloolefin copolymer, which differs from Example 1 in that the amounts of high-pigmentation channel black are 0.005 kg (Example 9) and 0.2 kg (Example 10), respectively, and other substances, amounts and steps are the same as those in Example 1.

[0094] Embodiment 11-12

[0095] A method for preparing a black cycloolefin copolymer, which differs from Example 1 in that the amounts of antioxidant 1010 are 0.5 kg (Example 11) and 4 kg (Example 12), respectively, and other substances, amounts and steps are the same as those in Example 1.

[0096] Embodiment 13

[0097] A method for preparing a black cycloolefin copolymer, which differs from Example 1 in that no PE wax powder is added, and other substances, amounts and steps are the same as those in Example 1.

[0098] Embodiment 14

[0099] A method for preparing a black cycloolefin copolymer, which differs from Example 1 in that heating is performed until the temperature reaches 100° C., and other substances, amounts and steps are the same as those in Example 1.

[0100] Embodiment 15

[0101] A method for preparing a black cycloolefin copolymer, which differs from Example 1 in that the amount of 15% methanol solution used is 1 kg, and other substances, amounts and steps are the same as those in Example 1.

[0102] Comparative Example 1

[0103] A method for preparing a black cyclic olefin copolymer comprises: mixing and granulating 0.02 kg of high-pigment channel black (with a particle size of 10-14 nm), 0.5 kg of PE wax powder, 1.5 kg of antioxidant 1010 (with a melting point of 115-118° C.) and 100 kg of COC particles, and then performing injection molding, wherein the injection molding temperature is 270° C. and the holding pressure is 50 MPa, to obtain the black cyclic olefin copolymer.

[0104] Comparative Example 2

[0105] A method for preparing a black cyclic olefin copolymer comprises: directly injecting and molding 0.02 kg of high-pigmentation channel black (with a particle size of 10-14 nm), 0.5 kg of PE wax powder, 1.5 kg of antioxidant 1010 (with a melting point of 115-118° C.) and 100 kg of COC particles after blending, wherein the injection molding temperature is 270° C. and the holding pressure is 50 MPa to obtain the black cyclic olefin copolymer.

[0106] Comparative Example 3

[0107] A method for preparing a black cyclic olefin copolymer comprises: directly injecting and molding 1 kg of black masterbatch, 1.5 kg of antioxidant 1010 (melting point 115-118° C.) and 100 kg of COC particles at a temperature of 270° C. and a holding pressure of 50 MPa to obtain the black cyclic olefin copolymer;

[0108] The black masterbatch is obtained by mixing 0.05 kg of high-pigment slot black (particle size of 10-14 nm), 0.5 kg of PE wax powder and 0.45 kg of cycloolefin copolymer and then granulating the mixture by twin-screw extrusion.

[0109] Comparative Example 4

[0110] A method for preparing a black cyclic olefin copolymer comprises: mixing and granulating 0.02 kg of high-pigmentation channel black (with a particle size of 10-14 nm), 0.5 kg of PE wax powder, 1.5 kg of antioxidant 1010 (with a melting point of 115-118° C.), 1 kg of toughening agent (POE8200 produced by DuPont) and 100 kg of COC particles, and then performing injection molding, wherein the injection molding temperature is 270° C. and the holding pressure is 50 MPa, to obtain the black cyclic olefin copolymer.

[0111] Comparative Example 5

[0112] A method for preparing a black cycloolefin copolymer, which differs from Example 1 in that antioxidant 1010 is not added, and other substances, amounts and steps are the same as those in Example 1.

[0113] Comparative Example 6

[0114] A method for preparing a black cycloolefin copolymer, which differs from Example 1 in that in step (2), cooling is performed by passing external circulating cooling water instead of passing liquid nitrogen, and other substances, amounts and steps are the same as those in Example 1.

[0115] Performance Testing

[0116] (1) Notched impact strength: Tested according to the test method in GB / T9341-2000.

[0117] (2) Color uniformity: Use a strong light of 500cd to illuminate at a distance of 50cm to observe whether there are white spots on the injection molded parts and whether the color of the spline is uniform.

[0118] (3) Others: Is there dust? Is there any powder residue in the barrel?

[0119] The injection molded parts of the black cycloolefin copolymers provided in Examples 1 to 15 and Comparative Examples 1 to 6 were tested according to the above test method. The test results are shown in Table 1:

[0120] Table 1

[0121]

[0122] From the data in Table 1, we can see that:

[0123] Compared with Comparative Examples 1 to 6, the black cyclic olefin copolymers provided in Examples 1 to 15 have more excellent mechanical properties and color uniformity, and effectively avoid the dust flying and injection molding machine pollution problems caused by conventional mixing, and are more suitable for preparing curved reflectors for HUDs.

[0124] The applicant declares that the present invention illustrates a black cyclic olefin copolymer and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a black cycloolefin copolymer, characterized in that: The preparation method comprises the following steps: (1) Wetting the black powder and the additives including the antioxidant with a solvent to obtain a wetted material; (2) mixing the wetted material obtained in step (1) with the cycloolefin copolymer particles, evacuating the mixture and heating the mixture to remove the solvent, then stopping the evacuation and introducing nitrogen vaporized from liquid nitrogen to cool the mixture, discharging the mixture, and obtaining black particles; (3) injection molding the black particles obtained in step (2) to obtain the black cycloolefin copolymer; The temperature of the system after heating to remove the solvent is lower than the glass transition temperature of the cycloolefin copolymer particles and higher than the melting point of the antioxidant by more than 5°C; The temperature of the system after cooling by introducing vaporized nitrogen from liquid nitrogen is at least 5°C lower than the melting point of the antioxidant; Based on 100 parts by weight of the cycloolefin copolymer particles, the amount of the solvent is 1.5 to 8 parts by weight, the amount of black powder is 0.01 to 0.1 parts by weight, and the amount of the antioxidant is 1 to 3 parts by weight; The black powder includes any one of carbon black, black titanium oxide or cobalt black, or a combination of at least two thereof; The auxiliary agent also includes a dispersant, and based on 100 parts by weight of the cycloolefin copolymer particles, the amount of the dispersant is 0.5 to 1 part by weight.

2. The preparation method according to claim 1, characterized in that: The solvent includes any one of water, methanol, ethanol or butanol, or a combination of at least two of them.

3. The preparation method according to claim 1, characterized in that: The nitrogen gas introduced into the liquid nitrogen for vaporization has an inlet flow rate of 20-100 L / min.

4. A black cycloolefin copolymer, characterized in that: The black cyclic olefin copolymer is prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the black cyclic olefin copolymer as claimed in claim 4 in preparing a HUD curved reflector.

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