Method for preparing foamed material by critical foaming

Abstract

The present invention relates to the field of foaming technology, specifically, the present invention relates to C08G101 / 00. A method for preparing chlorinated polyethylene-containing materials by supercritical foaming, which includes the following steps: (1) Put the chlorinated polyethylene-containing materials into a reactor, add water and a foaming nucleating agent, and then close the reactor cover; (2) Heat to 50-80°C; (3) Introduce supercritical carbon dioxide into the reactor, and saturate the chlorinated polyethylene-containing materials to adsorb the supercritical carbon dioxide; (4) Take out the chlorinated polyethylene-containing materials and treat them in an environment of 100-150°C for 1-5min. This preparation method is simple, environmentally friendly, highly efficient, and low cost; the uniform micropores improve the elasticity of the foamed material while reducing the density of the material, and the density of the resulting foamed material is 0.2-0.3g / cm. 3 and the cell walls are thin.

Description

[Technical field]

[0001] The present invention relates to the field of foaming technology, in particular to C08G101 / 00, and more particularly to a method for preparing foamed materials by supercritical foaming. [Background technology]

[0002] Salt polyethylene has excellent weather resistance and solvent resistance, so it is widely used. In CN201610058673, chlorinated polyethylene, filler, foaming agent, crosslinking agent, lubricant and stabilizer are kneaded together to carry out molding, vulcanization and foaming, and the resulting foamed material has weather resistance, chemical resistance and mechanical properties, but the problem of cell hole density cannot be solved. At the same time, because a chemical foaming agent is used to knead with the raw materials, the foaming is not controlled, and it is difficult to ensure the uniformity and flatness of the cell holes. Therefore, it is necessary to provide a foaming method to solve the problem of uncontrollable foaming, ensure the uniformity and flatness of the cell holes, and at the same time increase the density of the foaming, and expand the application scope of chlorinated polyethylene-containing materials. Summary of the Invention

[0003] In response to some of the problems existing in the prior art, a first aspect of the present invention provides a method for preparing a foamed material by supercritical foaming, comprising the steps of:

[0004] Put the chlorinated polyethylene-containing material into the reactor, add water and foaming nucleating agent, close the reactor cover, and heat to 50-80℃.

[0005] Supercritical carbon dioxide is introduced into the reactor, and the chlorinated polyethylene-containing material is saturated with the supercritical carbon dioxide to adsorb it.

[0006] The chlorinated polyethylene-containing material is taken out and treated in an environment of 100-150°C for 1-5 minutes.

[0007] The water content described in the present application is not particularly limited as long as it can immerse the chlorinated polyethylene-containing material, and specifically, it can be selected in a usual manner by those skilled in the art.

[0008] In a preferred embodiment, water occupies 60-80% of the volume of the reactor, more preferably 72 wt%.

[0009] The foam nucleating agent described in the present application is not particularly limited and can be selected by those skilled in the art in a conventional manner.

[0010] In one embodiment, the foam nucleating agent comprises 0.05-0.1 wt% of the water, preferably 0.08 wt%.

[0011] Applicants have unexpectedly discovered that the foam nucleating agent becomes rapidly effective when the foam nucleating agent comprises 0.05-0.1 wt % of the water.

[0012] Examples of the foam nucleating agent include calcium carbonate, clay, fibrous crystals, butane, and pentane.

[0013] In one embodiment, the foam nucleating agent is pentane.

[0014] Preferably, the pentanes include cyclopentane and n-pentane.

[0015] More preferably, the weight ratio of cyclopentane to n-pentane is (4-6):1, more preferably 5:1.

[0016] The applicant has unexpectedly discovered that when cyclopentane and n-pentane are added to a reaction furnace in a specific ratio and the chlorinated polyethylene-containing material contains the specific graphene of the present application, the non-uniform nucleation occurring in the foaming of the chlorinated polyethylene-containing material can be effectively avoided, the size of the bubble pores can be reduced, and the density of the bubble pores can be increased.

[0017] In one embodiment, step (2) comprises heating to 70°C.

[0018] Applicants have unexpectedly discovered that when heated to 50-80°C, and especially at 70°C, the final size of the resulting bubble pores is similar, with only minor differences.

[0019] In one embodiment, in step (3), supercritical carbon dioxide is introduced so that the pressure in the reactor is 20-30 MPa, preferably 25-28 MPa, more preferably 26 MPa.

[0020] The applicant has unexpectedly discovered that when supercritical carbon dioxide is introduced so that the pressure in the reactor is 20-30 MPa, the time required for the chlorinated polyethylene-containing material of the present application to reach a saturated state for adsorbing supercritical carbon dioxide is relatively short, thereby improving production efficiency.

[0021] Preferably, the supercritical carbon dioxide is introduced stepwise.

[0022] The phased introduction method of the present application involves intermittent introduction of supercritical carbon dioxide.

[0023] In a preferred embodiment, in step (3), supercritical carbon dioxide is first introduced at a rate of 2-5 MPa / s until the pressure in the reactor is 8-10 MPa, and maintained for 15-20 min; then supercritical carbon dioxide is again introduced at a rate of 0.5-1 MPa / s until the pressure in the reactor is 12-15 MPa, and maintained for 10-15 min; finally, supercritical carbon dioxide is introduced at a rate of 2-5 MPa / s until the pressure in the reactor is 20-30 MPa, and maintained for a certain time until the chlorinated polyethylene material is saturated and adsorbs the supercritical carbon dioxide.

[0024] In a more preferred embodiment, in step (3), supercritical carbon dioxide is first introduced at a rate of 3 MPa / s so that the pressure in the reactor becomes 8 MPa, and this is maintained for 18 minutes. Next, supercritical carbon dioxide is again introduced at a rate of 0.6 MPa / s so that the pressure in the reactor becomes 13 MPa, and this is maintained for 12 minutes. Finally, supercritical carbon dioxide is introduced at a rate of 2 MPa / s so that the pressure in the reactor becomes 26 MPa, and this is maintained for a certain period of time until the chlorinated polyethylene material becomes saturated and adsorbs the supercritical carbon dioxide.

[0025] The applicant has confirmed in the laboratory that when supercritical carbon dioxide is introduced so that the pressure in the reactor is 2-30 MPa, the saturation and adsorption efficiency can be improved while the uniformity and density of the pores of the final foamed material obtained by this method cannot meet the requirements. The applicant has found during research that the uniformity and density of the pores of the final foamed material can meet the requirements when supercritical carbon dioxide is introduced stepwise, especially when supercritical carbon dioxide is first introduced at a speed of 2-5 MPa / s so that the pressure in the reactor is 8-10 MPa, and held for 15-20 minutes, then introduced again at a speed of 0.5-1 MPa / s so that the pressure in the reactor is 12-15 MPa, and held for 10-15 minutes, and finally introduced at a speed of 2-5 MPa / s so that the pressure in the reactor is 20-30 MPa. The applicant believes that the reason for this is that when supercritical carbon dioxide is introduced under these specific conditions, it can completely diffuse into the chlorinated polyethylene-containing material, thereby avoiding the influence on diffusion within the chlorinated polyethylene-containing material due to the diffusion resistance caused by the viscosity when introducing supercritical carbon dioxide, while at the same time avoiding the formation of a bubble barrier on the surface of the chlorinated polyethylene-containing material when introducing the supercritical fluid.

[0026] In one embodiment, step (4) involves taking out the chlorinated polyethylene material and treating it in an environment of 140° C. for 3 minutes.

[0027] Applicant has unexpectedly discovered that when treated in an environment of 100-150°C for 1-5 minutes, the resulting foamed material can avoid the situation of cell pore growth within or on the boundaries of the cell pores.

[0028] The type of chlorinated polyethylene-containing material described in this application is not particularly limited and can be routinely selected by one skilled in the art.

[0029] The chlorinated polyethylene-containing materials described in this application can be produced in-house or purchased.

[0030] In one embodiment, the chlorinated polyethylene containing material is graphene.

[0031] In one embodiment, the method for preparing the chlorinated polyethylene-containing material is as follows: 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, and then extruded and granulated using a single-screw extruder at 100-150°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 10-50KGy to obtain a chlorinated polyethylene-containing material.

[0032] In one embodiment, the method for preparing the chlorinated polyethylene-containing material is as follows: 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, and then extruded and granulated using a single-screw extruder, and extruded at 120°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 35 KGy to obtain a chlorinated polyethylene-containing material.

[0033] The chlorinated polyethylene described in this application is not particularly limited and can be routinely selected by one skilled in the art.

[0034] In one embodiment, the chlorinated polyethylene is purchased from Sichuan Jinsen Plastics Co., Ltd. and is branded as JS / Jinsen.

[0035] The natural rubber is purchased from Taizhou Zhonghong Waste Rubber Comprehensive Utilization Co., Ltd., and is called natural regenerated fine rubber.

[0036] The calcium zinc stabilizer is purchased from Jinan Hui Jinchuan Trading Co., Ltd.

[0037] The graphene was purchased from Shandong Xiangzhao New Materials Co., Ltd., with the brand being Xiangzhao and the model number being 001.

[0038] The undisclosed portions of the method for preparing the chlorinated polyethylene-containing material of this application can be routinely selected by one skilled in the art.

[0039] A second aspect of the present invention provides a foamed material prepared by the method for preparing a foamed material by supercritical foaming. Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] The preparation method is simple and environmentally friendly, with high efficiency and low cost. The uniform micropores improve the elasticity of the foamed material while reducing the density of the material. The density of the resulting foamed material is 0.2-0.3g / cm. 3 and the cell walls are thin.

[0041] When a certain content of foam nucleating agent is adopted, especially 0.05-0.1wt%, the foam nucleating agent can rapidly exert its effect.

[0042] When the foaming nucleating agent contains a specific ratio of cyclopentane and n-pentane, and the chlorinated polyethylene-containing material contains the specific graphene of the present application, it is possible to effectively avoid non-uniform nucleation occurring in the foaming of the chlorinated polyethylene-containing material, while simultaneously reducing the size of the bubble holes and increasing the density of the bubble holes.

[0043] In the present application, when the temperature is heated to 50-80° C. in step (2), especially at 70° C., the final size of the obtained bubble pores is similar, and the difference is small.

[0044] When supercritical carbon dioxide is introduced so that the pressure in the reactor is 20-30 MPa, the time required for the chlorinated polyethylene-containing material of the present application to reach a saturated state for adsorbing supercritical carbon dioxide is relatively short, which can improve production efficiency.

[0045] When the method of gradually introducing supercritical carbon dioxide of the present application is adopted, the uniformity and density of the bubble holes can meet the requirements.

[0046] The present application shows that when the foamed material is treated in an environment of 100-150°C for 1-5 minutes, the foamed material can avoid the situation of cell pores growing within or on the boundaries of the cell pores. [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 is a SEM image of the foamed material obtained in Example 1 of the present invention. [Diagram 2] FIG. 2 is a SEM image of the foamed material obtained according to Example 5 of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The present invention will now be described through specific embodiments, but is not limited to the following specific examples. EXAMPLES

[0049] EXAMPLES

[0050] Example 1 of the present invention provides a method for preparing a foamed material by supercritical foaming, which is specifically as follows:

[0051] 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, then extruded and granulated using a single-screw extruder, and extruded at 100°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 10 KGy to obtain a chlorinated polyethylene-containing material.

[0052] Put the chlorinated polyethylene-containing material into the reactor, add water that accounts for 60% of the reactor volume, add the foaming nucleating agent, and then close the reactor cover, where the foaming nucleating agent accounts for 0.05 wt% of the water, and the foaming nucleating agent is cyclopentane and n-pentane in a weight ratio of 4:1.

[0053] Heat to 50°C.

[0054] Supercritical carbon dioxide is introduced at a rate of 2 MPa / s until the pressure in the reactor becomes 8 MPa, and this is maintained for 15 minutes. Next, supercritical carbon dioxide is introduced again at a rate of 0.5 MPa / s until the pressure in the reactor becomes 12 MPa, and this is maintained for 10 minutes. Finally, supercritical carbon dioxide is introduced at a rate of 2 MPa / s until the pressure in the reactor becomes 20 MPa, and this is maintained for a certain period of time until the chlorinated polyethylene material becomes saturated and adsorbs the supercritical carbon dioxide.

[0055] The chlorinated polyethylene-containing material is removed and treated in a 100°C environment for 5 minutes.

[0056] The chlorinated polyethylene is purchased from Sichuan Jinsen Plastics Co., Ltd., brand is JS / Jinsen. The natural rubber is purchased from Taizhou Zhonghong Waste Rubber Comprehensive Utilization Co., Ltd., brand is natural regenerated fine rubber. The calcium zinc stabilizer is purchased from Jinan Hui Jinchuan Trading Co., Ltd. The graphene is purchased from Shandong Xiangzhao New Material Co., Ltd., brand is Xiangzhao, model number is 001.

[0057] The SEM image of the foamed material obtained in this example is shown in Figure 1. As can be seen from the figure, the cells of the foamed material are regular and the density is relatively large. EXAMPLES

[0058] Example 2 of the present invention provides a method for preparing a foamed material by supercritical foaming, which is specifically as follows:

[0059] 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, then extruded and granulated using a single-screw extruder, and extruded at 150°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 50 KGy to obtain a chlorinated polyethylene-containing material.

[0060] Put the chlorinated polyethylene-containing material into the reactor, add water that accounts for 80% of the reactor volume, add the foaming nucleating agent, and then close the reactor cover, where the foaming nucleating agent accounts for 0.1 wt% of the water, and the foaming nucleating agent is cyclopentane and n-pentane in a weight ratio of 6:1.

[0061] Heat to 80°C.

[0062] Supercritical carbon dioxide is introduced at a rate of 5 MPa / s until the pressure in the reactor becomes 10 MPa, and this is maintained for 20 minutes. Next, supercritical carbon dioxide is introduced again at a rate of 1 MPa / s until the pressure in the reactor becomes 15 MPa, and this is maintained for 15 minutes. Finally, supercritical carbon dioxide is introduced at a rate of 5 MPa / s until the pressure in the reactor becomes 30 MPa, and this is maintained for a certain period of time until the chlorinated polyethylene material becomes saturated and adsorbs the supercritical carbon dioxide.

[0063] The chlorinated polyethylene-containing material is taken out and treated in an environment of 150°C for 1 minute.

[0064] The chlorinated polyethylene is purchased from Sichuan Jinsen Plastics Co., Ltd., brand is JS / Jinsen. The natural rubber is purchased from Taizhou Zhonghong Waste Rubber Comprehensive Utilization Co., Ltd., brand is natural regenerated fine rubber. The calcium zinc stabilizer is purchased from Jinan Hui Jinchuan Trading Co., Ltd. The graphene is purchased from Shandong Xiangzhao New Material Co., Ltd., brand is Xiangzhao, model number is 001. EXAMPLES

[0065] Example 3 of the present invention provides a method for preparing a foamed material by supercritical foaming, which is specifically as follows:

[0066] 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, and then extruded and granulated using a single-screw extruder, and extruded at 120°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 35 KGy to obtain a chlorinated polyethylene-containing material.

[0067] Put the chlorinated polyethylene-containing material into the reactor, add water that accounts for 72% of the reactor volume, add the foaming nucleating agent, and then close the reactor cover, where the foaming nucleating agent accounts for 0.08 wt% of the water, and the foaming nucleating agent is cyclopentane and n-pentane in a weight ratio of 5:1.

[0068] Heat to 70°C.

[0069] Supercritical carbon dioxide is introduced at a rate of 3 MPa / s until the pressure in the reactor reaches 8 MPa, and this is maintained for 18 minutes. Then, supercritical carbon dioxide is introduced again at a rate of 0.6 MPa / s until the pressure in the reactor reaches 13 MPa, and this is maintained for 12 minutes. Finally, supercritical carbon dioxide is introduced at a rate of 2 MPa / s until the pressure in the reactor reaches 26 MPa, and this is maintained for a certain period of time until the chlorinated polyethylene material is saturated and adsorbs the supercritical carbon dioxide.

[0070] The chlorinated polyethylene-containing material is removed and treated in an environment of 140°C for 3 minutes.

[0071] The chlorinated polyethylene is purchased from Sichuan Jinsen Plastics Co., Ltd., brand is JS / Jinsen. The natural rubber is purchased from Taizhou Zhonghong Waste Rubber Comprehensive Utilization Co., Ltd., brand is natural regenerated fine rubber. The calcium zinc stabilizer is purchased from Jinan Hui Jinchuan Trading Co., Ltd. The graphene is purchased from Shandong Xiangzhao New Material Co., Ltd., brand is Xiangzhao, model number is 001. EXAMPLES

[0072] Example 4 of the present invention provides a method for preparing a foamed material by supercritical foaming, which is specifically as follows:

[0073] 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, and then extruded and granulated using a single-screw extruder, and extruded at 120°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 35 KGy to obtain a chlorinated polyethylene-containing material.

[0074] Put the chlorinated polyethylene-containing material into the reactor, add water that accounts for 72% of the reactor volume, add the foaming nucleating agent, and then close the reactor cover, where the foaming nucleating agent accounts for 0.08 wt% of the water, and the foaming nucleating agent is cyclopentane and n-pentane in a weight ratio of 5:1.

[0075] Heat to 70°C.

[0076] Supercritical carbon dioxide is introduced at a rate of 3 MPa / s so that the pressure inside the reactor becomes 26 MPa, and the reaction is maintained for a certain period of time until the chlorinated polyethylene material becomes saturated and adsorbs the supercritical carbon dioxide.

[0077] The chlorinated polyethylene-containing material is removed and treated in an environment of 140°C for 3 minutes.

[0078] The chlorinated polyethylene is purchased from Sichuan Jinsen Plastics Co., Ltd., brand is JS / Jinsen. The natural rubber is purchased from Taizhou Zhonghong Waste Rubber Comprehensive Utilization Co., Ltd., brand is natural regenerated fine rubber. The calcium zinc stabilizer is purchased from Jinan Hui Jinchuan Trading Co., Ltd. The graphene is purchased from Shandong Xiangzhao New Material Co., Ltd., brand is Xiangzhao, model number is 001. EXAMPLES

[0079] Example 5 of the present invention provides a method for preparing a foamed material by supercritical foaming, which is specifically as follows:

[0080] 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, and then extruded and granulated using a single-screw extruder, and extruded at 120°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 35 KGy to obtain a chlorinated polyethylene-containing material.

[0081] Put the chlorinated polyethylene-containing material into the reactor, add water that accounts for 72% of the reactor volume, add the foaming nucleating agent, and then close the reactor cover, where the foaming nucleating agent accounts for 0.08 wt% of the water, and the foaming nucleating agent is cyclopentane and n-pentane in a weight ratio of 5:1.

[0082] Heat to 70°C.

[0083] Supercritical carbon dioxide is introduced at a rate of 3 MPa / s until the pressure in the reactor reaches 8 MPa, and this is maintained for 18 minutes. Then, supercritical carbon dioxide is introduced again at a rate of 0.6 MPa / s until the pressure in the reactor reaches 13 MPa, and this is maintained for 12 minutes. Finally, supercritical carbon dioxide is introduced at a rate of 2 MPa / s until the pressure in the reactor reaches 26 MPa, and this is maintained for a certain period of time until the chlorinated polyethylene material is saturated and adsorbs the supercritical carbon dioxide.

[0084] The chlorinated polyethylene-containing material is taken out and treated in an environment of 160°C for 3 minutes.

[0085] The chlorinated polyethylene is purchased from Sichuan Jinsen Plastics Co., Ltd., brand is JS / Jinsen. The natural rubber is purchased from Taizhou Zhonghong Waste Rubber Comprehensive Utilization Co., Ltd., brand is natural regenerated fine rubber. The calcium zinc stabilizer is purchased from Jinan Hui Jinchuan Trading Co., Ltd. The graphene is purchased from Shandong Xiangzhao New Material Co., Ltd., brand is Xiangzhao, model number is 001.

[0086] The SEM image of the foamed material obtained in this example is shown in Figure 2. As can be seen from the figure, the number of cells in the foamed material is increased. EXAMPLES

[0087] Example 6 of the present invention provides a method for preparing a foamed material by supercritical foaming, which is specifically as follows:

[0088] 65 parts by weight of chlorinated polyethylene, 10 parts by weight of natural rubber, 3 parts by weight of calcium zinc stabilizer, 10 parts by weight of graphene, 0.2 parts by weight of stearic acid, and 10 parts by weight of dioctyl phthalate are mixed, and then extruded and granulated using a single-screw extruder, and extruded at 120°C to obtain a molded plate. The obtained molded plate is irradiated and crosslinked with an irradiation dose of 35 KGy to obtain a chlorinated polyethylene-containing material.

[0089] Put the chlorinated polyethylene-containing material into the reactor, add water that accounts for 72% of the reactor volume, add the foaming nucleating agent, and then close the reactor cover, where the foaming nucleating agent accounts for 0.08 wt% of the water, and the foaming nucleating agent is cyclopentane and n-pentane in a weight ratio of 2:1.

[0090] Heat to 70°C.

[0091] Supercritical carbon dioxide is introduced at a rate of 3 MPa / s until the pressure in the reactor reaches 8 MPa, and this is maintained for 18 minutes. Then, supercritical carbon dioxide is introduced again at a rate of 0.6 MPa / s until the pressure in the reactor reaches 13 MPa, and this is maintained for 12 minutes. Finally, supercritical carbon dioxide is introduced at a rate of 2 MPa / s until the pressure in the reactor reaches 26 MPa, and this is maintained for a certain period of time until the chlorinated polyethylene material is saturated and adsorbs the supercritical carbon dioxide.

[0092] The chlorinated polyethylene-containing material is removed and treated in an environment of 140°C for 3 minutes.

[0093] The chlorinated polyethylene is purchased from Sichuan Jinsen Plastics Co., Ltd., brand is JS / Jinsen. The natural rubber is purchased from Taizhou Zhonghong Waste Rubber Comprehensive Utilization Co., Ltd., brand is natural regenerated fine rubber. The calcium zinc stabilizer is purchased from Jinan Hui Jinchuan Trading Co., Ltd. The graphene is purchased from Shandong Xiangzhao New Material Co., Ltd., brand is Xiangzhao, model number is 001. (Performance evaluation)

[0094] Cell void morphology: The cell void morphology of each of the foamed materials obtained in Examples 1-6 was observed under a microscope, and recorded as to whether the cell voids were neat or whether there was overlapping of the cell voids. The overlapping of the cell voids refers to the presence of additional cell voids within the cell voids. Cell pore density: The cell pore density of the foamed materials obtained in Examples 1 to 6 was calculated. The cell pore density is the number of cell pores per unit volume, and the unit is pores / cm. 3 , density is 9×10 7 pieces / cm 3 If it exceeds 9 x 10, it passes. 7 pieces / cm 3 Anything less will be recorded as a failure. [Table 1]

Claims

1. A method for preparing a foamed material by supercritical foaming, comprising the steps of: Step (1): Put the chlorinated polyethylene-containing material into the reactor, add water and a foaming nucleating agent, and then close the reactor lid. The foaming nucleating agent is cyclopentane and n-pentane in a weight ratio of (4-6):

1. Step (2): Heat to 50-80℃. Step (3): Supercritical carbon dioxide is gradually introduced into the reactor, and the chlorinated polyethylene-containing material is saturated with the supercritical carbon dioxide to adsorb it. Step (4): Remove the chlorinated polyethylene-containing material and treat it in an environment of 100-150°C for 1-5 minutes.

2. The method for preparing a foamed material by supercritical foaming according to claim 1, characterized in that in step (3), supercritical carbon dioxide is introduced so that the pressure in the reactor becomes 20-30 MPa.

3. The method for preparing a foamed material by supercritical foaming according to claim 2 is characterized in that in step (3), supercritical carbon dioxide is first introduced at a speed of 2-5 MPa / s so that the pressure in the reactor becomes 8-10 MPa, and this is maintained for 15-20 min, then supercritical carbon dioxide is introduced again at a speed of 0.5-1 MPa / s so that the pressure in the reactor becomes 12-15 MPa, and this is maintained for 10-15 min, and finally supercritical carbon dioxide is introduced at a speed of 2-5 MPa / s so that the pressure in the reactor becomes 20-30 MPa, and this is maintained for a certain time until the chlorinated polyethylene-containing material becomes saturated and adsorbs the supercritical carbon dioxide.

4. The method for preparing a foamed material by supercritical foaming according to any one of claims 1 to 3, wherein in step (4), the chlorinated polyethylene-containing material is taken out and treated in an environment of 140°C for 3 minutes.

5. The method for preparing foamed material by supercritical foaming as described in claim 4, characterized in that the water occupies 60-80% of the volume of the reaction furnace.

6. The method for preparing a foamed material by supercritical foaming as described in claim 5, characterized in that the foaming nucleating agent accounts for 0.05-0.1 wt% of water.

7. A method for preparing a foamed material by supercritical foaming according to claim 5 or 6, characterized in that the foaming nucleating agent is selected from one or more of calcium carbonate, clay, fibrous crystals, butane and pentane.

8. The method for preparing a foamed material by supercritical foaming according to claim 7, characterized in that the chlorinated polyethylene-containing material contains graphene.

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