Composite heat-insulating coating for granulation template and preparation process of composite heat-insulating coating

Abstract

The invention belongs to the technical field of granulation template processing, and discloses a composite heat insulation coating for a granulation template and a preparation technology of the composite heat insulation coating. The heat-insulating coating is prepared from the following raw materials in parts by weight: 1-5 parts of modified graphene, 5-20 parts of a dispersing agent, 4-10 parts of benzyltriethylammonium chloride, 20-40 parts of a WPU solution and 20-60 parts of zirconium oxide; the preparation method comprises the following steps: modifying graphene, preparing a modified graphene solution from the modified graphene, benzyltriethylammonium chloride and a dispersing agent, and putting the modified graphene solution, zirconium oxide and a waterborne polyurethane emulsion into a ball mill for ball milling to obtain a heat-insulating coating; the heat insulation coating for the granulation template has relatively strong interface adhesion, wear resistance and lubricity, can be used in the granulation template prepared from various materials, and effectively improves the temperature difference of the discharge side of the granulation template.

Description

Technical Field

[0001] The present invention belongs to the technical field of granulation template processing, and particularly relates to a composite heat-insulating coating for a granulation template and a preparation process thereof. Background Art

[0002] The granulation template is one of the important components in the production of polyethylene and polystyrene extrusion pelletizing. To ensure the fluidity of the material, generally, heat-conducting oil is used to heat the granulation process, and the granulation is carried out by immersing the granulation port, that is, the discharge side, in flowing cold water to let the flowing water carry away the granulation. This will inevitably cause a certain temperature difference at various parts of the granulation template, resulting in damage to the granulation template; in addition, the discharge holes of the existing granulation templates are generally concentrated in the fan-shaped area, and the heat dissipation areas of the middle area and the edge area are inconsistent, resulting in a certain temperature difference between the discharge holes, resulting in uneven granulation size.

[0003] To ensure that the temperature in the entire fan-shaped area of the template is basically the same during operation and the heat flow field is maintained consistent, certain heat-insulating measures need to be taken for the granulation template. For example, chrome plating heat insulation treatment, chrome plating is a common mold surface; carburizing heat insulation treatment method, carburizing treatment involves immersing the mold surface in a carburizing agent solution, and through a high-temperature and high-pressure treatment process, carbon atoms penetrate into the mold surface to form a hard carburized layer; coating heat-insulating paint, coating a layer of heat-insulating paint on the mold surface can form a heat-insulating layer to effectively reduce the increase in the mold surface temperature; adding a heat-insulating lining board, setting a heat-insulating lining board inside the template can prevent the heat transferred from the inside of the template to heat the template surface; optimizing the template structure, by reasonably arranging the shapes and distributions of the molten fluid channels and heat-conducting oil channels inside the template, the granulation temperature and flow rate at the template outlet tend to be consistent. Among them, coating a heat-insulating coating on the granulation template is a relatively common measure. Granulation templates made of different materials are required in different use fields and different application scenarios, such as stainless steel, cemented carbide, ceramics, etc. However, in the prior art, there is a lack of a heat-insulating coating that can not only ensure the heat-insulating effect but also be applicable to different materials.

[0004] To solve this problem, we hereby propose a composite heat-insulating coating for a granulation template and a preparation process thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite heat-insulating coating for a granulation template to solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A composite heat-insulating coating for a granulation template, including

[0008]

[0009] Modified graphene of the group.

[0010] Preferably, the raw materials for preparing the heat-insulating coating include, by weight:

[0011]

[0012] Preferably, the WPU solution is 50 - 80%.

[0013] Preferably, the raw materials containing modified graphene include, by weight:

[0014]

[0015] Preferably, the preparation process of the modified graphene includes:

[0016] A1: Put appropriate amounts of graphene and concentrated sulfuric acid into a ball mill, and after the reaction, wash with water and dry to obtain the first product;

[0017] A2: Treat the first product with plasma wave radiation in an environment of nitrogen and hydrogen, and filter and dry to obtain the second product;

[0018] A3: Take appropriate amounts of the second product, furfural, and catalyst and put them into a reaction kettle for extraction to obtain the modified graphene.

[0019] Preferably, the reaction conditions used in step A1 are that the rotation speed of the ball mill is 500 - 1000 r / min, the ball milling temperature is 100 - 150 °C, and the treatment time is 10 - 30 min;

[0020] Preferably, the reaction conditions for step A3 are a temperature of 60 - 100 °C and a treatment time of 0.5 - 2 h.

[0021] Preferably, the treatment method for step A2 includes:

[0022] B1: Mix the first product and deionized water in a mass ratio of 1:(5 - 10), and perform ultrasonic treatment to prepare a suspension of the first product;

[0023] B2: Put the suspension of the first product into a plasma reactor with a power of 60 - 150 w, and introduce nitrogen and hydrogen, start the reactor for treatment, and the treatment time is 0.2 - 1 h.

[0024] Preferably, the catalyst can be one or more of acetic acid, ammonium chloride, ammonium bromide, tetrabutylammonium phosphate, cobalt, nickel, ruthenium, or copper.

[0025] Preferably, the dispersant is a sodium diphenylamine sulfonate solution or a poly(4-styrenesulfonic acid) sodium solution with a concentration of 10 - 20%.

[0026] Preferably, the particle sizes of the graphene include 50 mesh, 200 mesh, and 1000 mesh, among which the graphene of 50 mesh accounts for 5-10%, the graphene of 200 mesh accounts for 10-20%, and the graphene of 1000 mesh accounts for 70-85%.

[0027] The process for preparing a composite heat-insulating coating for a granulation template includes:

[0028] T1: Put an appropriate amount of graphene and concentrated sulfuric acid into a ball mill, and after the reaction ends, wash with water and dry to obtain a first product;

[0029] T2: Radiate the first product with plasma waves in an environment of nitrogen and hydrogen, and filter and dry to obtain a second product;

[0030] T3: Take an appropriate amount of the second product, furfural, and a catalyst and put them into a reaction kettle for extraction to obtain modified graphene;

[0031] T4: Put an appropriate amount of modified graphene, benzyltriethylammonium chloride, and a dispersant into an emulsifier to prepare a modified graphene solution;

[0032] T5: Put the modified graphene solution prepared in T4, zirconia, and WPU emulsion into a ball mill for ball milling to obtain a heat-insulating coating.

[0033] Preferably, in T4, the rotation speed of the emulsifier is 200-1000 r / min, and the treatment time is 0.5-2 h; in T5, the ball milling temperature is 220-240 °C, and the treatment time is 100-150 h.

[0034] The heat-insulating coating prepared by the present invention has the following advantages:

[0035] 1. The coating prepared by the present invention has strong adhesion and is not easy to fall off or peel off after long-term use

[0036] 2. After coating the granulation template with the coating prepared by the present invention, the heat loss in the fan-shaped area of the granulation template is small, the overall temperature is consistent, and the discharging is uniform

[0037] 3. The preparation method of the present invention is simple and the operation is reliable.

[0038] 4. The heat-insulating coating prepared by the present invention can not only be applied to a variety of materials, but also can be used for ceramic granulation templates, and the stability of the coating is excellent.

[0039] The composite coating prepared by the present invention has better adhesion, a wider application range, and less heat loss compared to a single wear-resistant / heat-resistant material, and is suitable for existing granulation templates. The heated material fluid flows through the flow channels, extrusion ports, and discharge ports of the template in sequence and then enters the cooling water. During this process, the heat-insulating coating reduces the heat loss of the discharge port immersed in the cooling water, maintains the temperature difference at each part of the discharge port basically consistent, ensures uniform discharging, and reduces the heat load of the cooling water.

[0040] The heat-insulating coating prepared by the present invention has strong interfacial adhesion, wear resistance, and lubricity, effectively improving the temperature difference on the discharging side of the granulation template.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] The heat-insulating coating of the present invention for granulation templates has strong interfacial adhesion, wear resistance, and lubricity, can be used in granulation templates prepared from various materials, and effectively improves the temperature difference on the discharging side of the granulation template. Specific embodiments

[0043] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0044] Example 1:

[0045] Preparation of modified graphene:

[0046] Put 10 parts of graphene and 1 part of concentrated sulfuric acid into a ball mill. The rotation speed of the ball mill is 500 r / min, the ball milling temperature is 100 °C, and the treatment time is 10 min. After the reaction, wash with water and dry to obtain the first product, in which 5% of the graphene is 50 mesh, 10% of the graphene is 200 mesh, and the proportion of 1000-mesh graphene is 85%;

[0047] Mix the first product and deionized water in a mass ratio of 1:5 and perform ultrasonic treatment to prepare a suspension of the first product; then put the suspension of the first product into a plasma reactor with a power of 60 w, introduce nitrogen and hydrogen, start the reactor for plasma wave radiation treatment, the treatment time is 0.2 h, and filter and dry to obtain the second product;

[0048] Take 10 parts of an appropriate amount of the second product, 3 parts of furfural, 10 parts of dichloromethane, and 0.5 part of acetic acid, put them into a reaction kettle, the process temperature is 60 °C, the treatment time is 0.5 h, and extract to obtain modified graphene containing groups.

[0049] Preparation of heat-insulating coating:

[0050] Put an appropriate amount containing 1 part of modified graphene, 4 parts of benzyltriethylammonium chloride, and 5 parts of a 10% sodium diphenylamine sulfonate solution into an emulsifier. The rotation speed of the emulsifier is 200 r / min, and the treatment time is 0.5 h to prepare a graphene solution;

[0051] Put the prepared graphene solution, 25 parts of zirconia, and 20 parts of a 50% WPU emulsion into a ball mill. The ball milling temperature is 220 °C, and after treatment for 100 h, a heat-insulating coating is obtained.

[0052] Example 2:

[0053] Preparation of modified graphene:

[0054] Put 20 parts of graphene and 3 parts of concentrated sulfuric acid into a ball mill. The rotation speed of the ball mill is 1000 r / min, the ball milling temperature is 150 °C, and the treatment time is 30 min. After the reaction, wash with water and dry to obtain a first product, in which 10% of the graphene is 50 mesh, 20% is 200 mesh, and 70% of the graphene is 1000 mesh;

[0055] Mix the first product and deionized water in a mass ratio of 1:10 and perform ultrasonic treatment to prepare a suspension of the first product; then put the suspension of the first product into a plasma reactor with a power of 150 w, introduce nitrogen and hydrogen, start the reactor for plasma wave radiation treatment, the treatment time is 1 h, and filter and dry to obtain a second product;

[0056] Take 20 parts of the second product, 5 parts of furfural, 20 parts of methanol, and 1 part of ammonium chloride, put them into a reaction kettle, the process temperature is 100 °C, the treatment time is 2 h, and extract to obtain modified graphene containing groups.

[0057] Preparation of heat-insulating coating:

[0058] Put 5 parts of modified graphene, 10 parts of benzyltriethylammonium chloride, and 20 parts of a 20% poly(4-styrenesulfonic acid) sodium solution into an emulsifier. The rotation speed of the emulsifier is 1000 r / min, and the treatment time is 2 h to prepare a graphene solution;

[0059] Put the prepared graphene solution, 65 parts of zirconia, and 40 parts of an 80% WPU emulsion into a ball mill. The ball milling temperature is 240 °C, and after treatment for 150 h, a heat-insulating coating is obtained.

[0060] Example 3:

[0061] Preparation of modified graphene:

[0062] Put 15 parts of graphene and 2 parts of concentrated sulfuric acid into a ball mill. The rotation speed of the ball mill is 700 r / min, the ball milling temperature is 120 °C, and the treatment time is 20 min. After the reaction, wash with water and dry to obtain the first product. Among them, 8% of the graphene is 50 mesh, 15% is 200 mesh, and 77% of the graphene is 1000 mesh;

[0063] Mix the first product and deionized water in a mass ratio of 1:8, and perform ultrasonic treatment to prepare a suspension of the first product; then put the suspension of the first product into a plasma reactor with a power of 100 w, and introduce nitrogen and hydrogen. Start the reactor for plasma wave radiation treatment. The treatment time is 0.5 h, and filter and dry to obtain the second product;

[0064] Take 15 parts of the second product, 4 parts of furfural, 15 parts of dichloromethane and 0.6 part of the catalyst tributylammonium phosphate, put them into a reaction kettle, the process temperature is 80 °C, and the treatment time is 1 h, and extract to obtain Modified graphene with groups.

[0065] Preparation of heat insulation coating:

[0066] Put an appropriate amount of 3 parts of modified graphene, 7 parts of benzyltriethylammonium chloride and 15 parts of a 16% sodium diphenylamine sulfonate solution into an emulsifier. The rotation speed of the emulsifier is 500 r / min, and the treatment time is 1 h to prepare a graphene solution;

[0067] Put the prepared graphene solution, 50 parts of zirconia, and 30 parts of a 60% WPU emulsion into a ball mill. The ball milling temperature is 230 °C, and treat for 130 h to obtain a heat insulation coating.

[0068] Comparative Example 1:

[0069] Preparation of modified graphene:

[0070] Put 15 parts of graphene, among which 8% of the graphene is 50 mesh and 92% of the graphene is 1000 mesh, and 2 parts of concentrated sulfuric acid into a ball mill. The rotation speed of the ball mill is 700 r / min, the ball milling temperature is 120 °C, and the treatment time is 20 min. After the reaction, wash with water and dry to obtain the first product;

[0071] Mix the first product and deionized water in a mass ratio of 1:8, and perform ultrasonic treatment to prepare a suspension of the first product; then put the suspension of the first product into a plasma reactor with a power of 100 w, and introduce nitrogen and hydrogen. Start the reactor for plasma wave radiation treatment. The treatment time is 0.5 h, and filter and dry to obtain the second product;

[0072] Take 15 parts of the second product, 4 parts of furfural, 15 parts of dichloromethane, and 0.6 part of the catalyst tributylammonium phosphate, and put them into a reaction kettle. The process temperature is 80 °C, the treatment time is 1 h, and extraction is carried out to obtain modified graphene containing the

[0073] Preparation of the heat-insulating coating:

[0074] Put an appropriate amount of 3 parts of modified graphene, 7 parts of benzyltriethylammonium chloride, and 15 parts of a 16% sodium diphenylamine sulfonate solution into an emulsifier. The rotation speed of the emulsifier is 500 r / min, and the treatment time is 1 h to prepare a graphene solution;

[0075] Put the prepared graphene solution, 50 parts of zirconia, and 30 parts of a 60% WPU emulsion into a ball mill. The ball milling temperature is 230 °C, and after treatment for 130 h, a heat-insulating coating is obtained.

[0076] Comparative Example 2:

[0077] Put an appropriate amount of 3 parts of graphene, 7 parts of benzyltriethylammonium chloride, and 15 parts of a 15% sodium diphenylamine sulfonate solution into an emulsifier. The rotation speed of the emulsifier is 500 r / min, and the treatment time is 1 h to prepare a graphene solution, in which 8% of the graphene is 50 mesh, 15% of the graphene is 200 mesh, and 77% of the graphene is 1000 mesh;

[0078] Put the prepared graphene solution, 50 parts of zirconia, and 30 parts of a 60% WPU emulsion into a ball mill. The ball milling temperature is 230 °C, and after treatment for 130 h, a heat-insulating coating is obtained.

[0079] Comparative Example 3:

[0080] Preparation of modified graphene:

[0081] Put 15 parts of graphene and 2 parts of concentrated sulfuric acid into a ball mill. The rotation speed of the ball mill is 700 r / min, the ball milling temperature is 120 °C, and the treatment time is 20 min. After the reaction, wash with water and dry to obtain the first product, in which 8% of the graphene is 50 mesh, 15% of the graphene is 200 mesh, and 77% of the graphene is 1000 mesh;

[0082] Mix the first product and deionized water in a mass ratio of 1:8, and perform ultrasonic treatment to prepare a suspension of the first product; then put the suspension of the first product into a plasma reactor with a power of 100 w, and introduce nitrogen and hydrogen, start the reactor for plasma wave radiation treatment, the treatment time is 0.5 h, and filter and dry to obtain the second product;

[0083] Take 15 parts of the second product, 4 parts of furfural, 15 parts of dichloromethane, and 0.6 part of the catalyst tributylammonium phosphate, and put them into a reaction kettle. The process temperature is 80 °C, the treatment time is 1 h, and extraction gives modified graphene containing the

[0084] Preparation of the heat-insulating coating:

[0085] Put an appropriate amount containing 3 parts of modified graphene and 15 parts of a 16% sodium diphenylamine sulfonate solution into an emulsifier. The rotation speed of the emulsifier is 500 r / min, and the treatment time is 1 h to prepare a graphene solution;

[0086] Put the prepared graphene solution, 50 parts of zirconia, and 30 parts of a 60% WPU emulsion into a ball mill. The ball milling temperature is 230 °C, and after treatment for 130 h, a heat-insulating coating is obtained.

[0087] Comparative Example 4:

[0088] Preparation of modified graphene:

[0089] Put 15 parts of graphene and 2 parts of concentrated sulfuric acid into a ball mill. The rotation speed of the ball mill is 700 r / min, the ball milling temperature is 120 °C, and the treatment time is 20 min. After the reaction, wash with water and dry to obtain the first product, where 8% is 50-mesh graphene, 15% is 200-mesh graphene, and 77% is 1000-mesh graphene;

[0090] Mix the first product and deionized water in a mass ratio of 1:8, and perform ultrasonic treatment to prepare a suspension of the first product; then put the suspension of the first product into a plasma reactor with a power of 100 w, and introduce nitrogen and hydrogen. Start the reactor for plasma wave radiation treatment. The treatment time is 0.5 h, and after filtration and drying, the second product is obtained;

[0091] Take 15 parts of the second product, 4 parts of benzaldehyde, 15 parts of dichloromethane, and 0.6 part of the catalyst tributylammonium phosphate, and put them into a reaction kettle. The process temperature is 80 °C, the treatment time is 1 h, and extraction gives modified graphene.

[0092] Preparation of the heat-insulating coating:

[0093] Put an appropriate amount containing 3 parts of modified graphene, 7 parts of benzyltriethylammonium chloride, and 15 parts of a 16% sodium diphenylamine sulfonate solution into an emulsifier. The rotation speed of the emulsifier is 500 r / min, and the treatment time is 1 h to prepare a graphene solution;

[0094] Put the prepared graphene solution, 50 parts of zirconia, and 30 parts of a 60% WPU emulsion into a ball mill. The ball milling temperature is 230 °C, and after treatment for 130 h, a heat-insulating coating is obtained.

[0095] Comparative Example 5

[0096] Commercially available heat-insulating coating, for example: Cotronics Corp. 9410.

[0097] Usage of the granulation die after coating the coating in the production line:

[0098] Examples 1-3 and Comparative Examples 1-5 were respectively used to vacuum coat the inner heat tracing channel, outer heat tracing channel, feed groove, and the contact between the template and the cooling water of the granulation template. The coating thickness at the contact was 2 μm, and at other positions was 1 μm. Then the granulation template was installed on the equipment, and the discharging conditions of the corresponding materials in Examples 1-3 and Comparative Examples 1-5 were observed. Five parallel tests were conducted for each sample in Examples 1-3 and Comparative Examples 1-5.

[0099] Hardness test:

[0100] It was determined according to GB / T 6739-1996 "Pencil Method for Determining Film Hardness". The determination results were divided into 6H-6B, with 6H being the highest.

[0101] Adhesion test: Cross-cut method: The coating specimen was tested according to the national standard GB / T 9286-1998 "Cross-Cut Test for Paints and Varnishes".

[0102] Water resistance test:

[0103] It was carried out according to the national standard GB / T 1733-1993 "Method for Determining Water Resistance of Films".

[0104] Table 1 Test Results (Stainless Steel Die)

[0105]

[0106] Table 2 Test Results (Ceramic Die)

[0107]

[0108] It can be seen from the results of Table 1 and Table 2 that the hardness of Examples 1-3 was 5H, and no blistering, cracking, or peeling occurred when used on either stainless steel granulation dies or ceramic granulation dies, and the adhesion was grade 1. The discharging was uniform during use, indicating that Examples 1-3 maintained the same temperature difference at each part of the discharging port during actual use, and the heat load of the cooling water was low.

[0109] From the comparison between Examples 1-3 and Comparative Example 1, it can be seen that when using Comparative Example 1 on either stainless steel dies or ceramic dies, blistering started to occur in the water resistance test, and the adhesion also decreased, but the discharging was not affected.

[0110] From the comparison between Examples 1-3 and Comparative Example 2, it can be seen that the water resistance and adhesion of Comparative Example 3 are worse when used in a ceramic mold than in a stainless steel mold.

[0111] From the comparison between Examples 1-3 and Comparative Example 3, it can be seen that the usage situation of Comparative Example 3 in a stainless steel mold remains unchanged, but its water resistance and adhesion become worse when used in a ceramic mold. Moreover, after using Comparative Example 3 in a ceramic mold, its water resistance and adhesion are much worse than those when using Examples 1-3.

[0112] From the comparison between Examples 1-3 and Comparative Example 4, it can be seen that the usage situation of Comparative Example 3 in a stainless steel mold remains unchanged, but its adhesion and discharging condition become worse when used in a ceramic mold.

[0113] From the comparison between Examples 1-3 and Comparative Example 5, it can be seen that when Comparative Example 5 is used in a stainless steel mold, its hardness remains unchanged, 80% of the samples have good water resistance, and 100% of them have good adhesion. However, when used in a ceramic mold, its adhesion is very poor and the discharging condition is also very poor.

[0114] Although the embodiments of the present invention have been shown and described (see the detailed description above), those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite thermal insulation coating for a granulation template, characterized in that: The thermal insulation coating comprises Modified graphene of groups; The raw materials for preparing the thermal insulation coating include, by weight:

2. The composite thermal insulation coating for a granulation template according to claim 1, characterized in that: The modified graphene raw material comprises, by weight:

3. The composite thermal insulation coating for a granulation template according to claim 2, characterized in that: The preparation process of the modified graphene comprises: A1: Put graphene and concentrated sulfuric acid in a weight ratio of (10-20):(1-3) into a ball mill, wash and dry after the reaction to obtain the first product; A2: treating the first product with plasma wave radiation in a nitrogen and hydrogen environment, filtering and drying to obtain the second product; A3: Take an appropriate amount of the second product, furfural and catalyst and put them into a reactor to extract modified graphene.

4. The composite thermal insulation coating for a granulation template according to claim 3, characterized in that: The reaction conditions used in step A1 are a ball mill speed of 500-1000 r / min, a ball mill temperature of 100-150° C., and a treatment time of 10-30 min; the reaction conditions in step A3 are a temperature of 60-100° C. and a treatment time of 0.5-2 h.

5. The composite thermal insulation coating for granulation template according to claim 3, characterized in that: The processing method of step A2 includes: B1: mixing the first product and deionized water in a mass ratio of 1:(5-10), and ultrasonically treating the mixture to prepare a first product suspension; B2: The first product suspension is put into a plasma reactor with a power of 60-150W, and nitrogen and hydrogen are introduced, and the reactor is started for treatment, and the treatment time is 0.2-1h.

6. The composite thermal insulation coating for a granulation template according to claim 2, characterized in that: The catalyst may be one or more of acetic acid, ammonium chloride, ammonium bromide, tributyl ammonium phosphate, cobalt, nickel, ruthenium or copper.

7. The composite thermal insulation coating for a granulation template according to claim 1, characterized in that: The dispersant is a sodium diphenylamine sulfonate solution or a sodium poly (4-styrene sulfonate) solution with a concentration of 10-20%.

8. The composite thermal insulation coating for a granulation template according to claim 2, characterized in that: The particle sizes of the graphene include 50 mesh, 200 mesh and 1000 mesh, wherein the graphene of 50 mesh contains 5-10%, the graphene of 200 mesh contains 10-20%, and the graphene of 1000 mesh accounts for 70-85%.

9. A process for preparing a composite thermal insulation coating for a granulation template, characterized in that: The process of the preparation process comprises: T1: Put appropriate amount of graphene and concentrated sulfuric acid into a ball mill, wash and dry after the reaction to obtain the first product; T2: treating the first product with plasma wave radiation in a nitrogen and hydrogen environment, filtering and drying to obtain a second product; T3: taking an appropriate amount of the second product, furfural and catalyst into a reactor, and extracting to obtain modified graphene; T4: adding appropriate amounts of modified graphene, benzyltriethylammonium chloride and dispersant into an emulsifier to prepare a modified graphene solution; T5: Put the modified graphene solution, zirconium oxide and WPU emulsion prepared in T4 into a ball mill for ball milling to obtain a thermal insulation coating.

10. The process for preparing a composite heat-insulating coating for a granulation template according to claim 9, characterized in that: The speed of the emulsifier in T4 is 200-1000 r / min, and the processing time is 0.5-2 h; the ball milling temperature in T5 is 220-240° C., and the processing time is 100-150 h.

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