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CN-122011902-A - Heat insulation coating for heat exchanger and preparation process thereof

CN122011902ACN 122011902 ACN122011902 ACN 122011902ACN-122011902-A

Abstract

The invention relates to the technical field of coatings and discloses a heat-insulating coating for a heat exchanger and a preparation process thereof, wherein the preparation process comprises the steps of adding epoxy resin and modified cardanol into dimethylbenzene, stirring for 10-15min at 600-800r/min, keeping stirring, sequentially adding a dispersing agent, a defoaming agent, modified graphene and titanium dioxide into the mixture, dispersing for 20-30min at a high speed, then reducing the rotating speed to 300-500r/min, adding hollow glass beads into the mixture, stirring for 8-10min at a low speed, finally adding a curing agent, continuously stirring for 5-8min, filtering and standing to obtain the heat-insulating coating for the heat exchanger. The heat-insulating coating for the heat exchanger has good heat insulation, water resistance and salt fog resistance.

Inventors

  • WANG XIAOHUA
  • SHI MIN
  • YUAN HANG
  • WANG DONG
  • HONG CHAO

Assignees

  • 宁波安信化工装备有限公司

Dates

Publication Date
20260512
Application Date
20260415

Claims (10)

  1. 1. The heat insulation coating for the heat exchanger is characterized by comprising, by weight, 35-40 parts of epoxy resin, 10-15 parts of modified cardanol, 0.5-1 part of modified graphene, 12-15 parts of hollow glass microspheres, 6-8 parts of titanium dioxide, 8-12 parts of a curing agent, 1-1.5 parts of a dispersing agent, 0.2-0.4 part of a defoaming agent and 15-20 parts of dimethylbenzene; The modified cardanol is obtained by reacting cardanol with epichlorohydrin to obtain epoxy cardanol and then reacting with hydrogen-containing silicone oil at the end; the modified graphene is obtained by reacting graphene oxide with 2-bromo-isobutyl bromide and then reacting with itaconic acid diperoxybutyl ethyl ester.
  2. 2. The heat insulating paint for heat exchangers according to claim 1, wherein the modified cardanol is prepared by the following steps: reacting cardanol with epoxy chloropropane in the presence of tetrabutylammonium bromide to obtain epoxy cardanol; and secondly, dissolving the epoxy cardanol and the hydrogen-containing silicone oil in a toluene solvent, and reacting under the catalysis of an isopropanol solution of chloroplatinic acid to obtain the modified cardanol.
  3. 3. The heat insulating paint for heat exchangers according to claim 2, wherein the amount ratio of cardanol, epichlorohydrin and tetrabutylammonium bromide in the first step is 6-7 g/18-21 g/0.15-0.2 g.
  4. 4. The heat-insulating coating for heat exchangers according to claim 2, wherein the amount ratio of the isopropanol solution of cardanol, hydrogen-terminated silicone oil, toluene and chloroplatinic acid in the step (ii) is 5-6 g/35-38 g/60-80 mL/0.1-0.12 mL.
  5. 5. The heat insulating coating for heat exchangers according to claim 1, wherein the modified graphene is prepared by the following steps: s1, reacting graphite powder with potassium permanganate in mixed acid of concentrated sulfuric acid and concentrated phosphoric acid to obtain graphene oxide; s2, dissolving graphene oxide and 2-bromoisobutyryl bromide in N, N-dimethylformamide, and reacting in the presence of triethylamine to obtain brominated graphene oxide; s3, reacting itaconic acid and perfluorobutyl alcohol under the catalysis of p-toluenesulfonic acid to obtain diperfluorobutyl ethyl itaconate; and S4, dissolving brominated graphene oxide and itaconic acid diperfluorobutyl ethyl ester in an N, N-dimethylformamide solvent, and reacting under the catalysis of pentamethyl diethylenetriamine and cuprous bromide to obtain modified graphene.
  6. 6. The heat-insulating paint for heat exchangers according to claim 5, wherein the amount ratio of graphite powder, potassium permanganate, concentrated sulfuric acid and concentrated phosphoric acid in S1 is 3-3.3g:18-19.5g:360-400mL:40-50mL.
  7. 7. The heat insulating paint for heat exchangers according to claim 5, wherein the amount ratio of graphene oxide, 2-bromoisobutyryl bromide, N-dimethylformamide and triethylamine in S2 is 1-1.2 g/10-12 mL/50-60 mL/6-7 mL.
  8. 8. The heat insulating paint for heat exchangers according to claim 5, wherein the ratio of itaconic acid, perfluorobutyl alcohol and p-toluene sulfonic acid in S3 is 1-1.1 g/4.3-4.4 g/0.01-0.02 g.
  9. 9. A heat insulating paint for a heat exchanger according to claim 5, wherein the amount ratio of brominated graphene oxide, diperfluorobutyl ethyl itaconate, N-dimethylformamide, pentamethyldiethylenetriamine and cuprous bromide in S4 is 0.1-0.12g:4.5-4.6g:12-15 mL:62-64. Mu.L:85-87 mg.
  10. 10. A process for preparing the heat-insulating paint for the heat exchanger, which is characterized in that the process comprises the steps of adding epoxy resin, modified cardanol, dispersing agent, defoaming agent, modified graphene, titanium pigment, hollow glass beads and curing agent into dimethylbenzene, and stirring to obtain the heat-insulating paint for the heat exchanger.

Description

Heat insulation coating for heat exchanger and preparation process thereof Technical Field The invention relates to the technical field of coatings, in particular to a heat-insulating coating for a heat exchanger and a preparation process thereof. Background In the operation process, the heat exchanger is often challenged by high-temperature, high-pressure and corrosive media and complex environmental conditions, the surface temperature of the heat exchanger is often obviously higher than the surrounding environment, so that serious heat loss is caused, a large amount of energy is wasted, production interruption is caused by equipment failure, and potential safety hazards are caused while the maintenance cost is increased. In order to improve the heat efficiency, prolong the service life and enhance the operation reliability of the heat exchanger, the surface of the heat exchanger is coated with heat insulation protective coating, however, the heat insulation coating for the heat exchanger commonly used at present has the problems of unbalanced heat insulation and temperature resistance and poor mechanical property and working condition suitability, and is difficult to meet the severe requirements of industrial scenes. How to avoid this phenomenon is therefore the key to solving the problem. As disclosed in the patent application publication No. CN114181571a, a heat-insulating coating and a preparation method thereof are disclosed, and the heat-insulating coating of the application has a synergistic effect of acrylic resin, aluminum silicate fiber and alumina gel microspheres, can inhibit the effect of solid and gaseous heat conduction in the heat-insulating coating, and improves the heat-insulating performance and mechanical properties of the obtained heat-insulating coating, but the water resistance and salt spray resistance are to be improved. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide the heat-insulating paint for the heat exchanger and the preparation process thereof, and the heat-insulating paint for the heat exchanger has good heat insulation, water resistance and salt spray resistance. The heat insulation coating for the heat exchanger comprises, by weight, 35-40 parts of epoxy resin, 10-15 parts of modified cardanol, 0.5-1 part of modified graphene, 12-15 parts of hollow glass microspheres, 6-8 parts of titanium dioxide, 8-12 parts of a curing agent, 1-1.5 parts of a dispersing agent, 0.2-0.4 part of a defoaming agent and 15-20 parts of dimethylbenzene; The modified cardanol is obtained by reacting cardanol with epichlorohydrin to obtain epoxy cardanol and then reacting with hydrogen-containing silicone oil at the end; the modified graphene is obtained by reacting graphene oxide with 2-bromo-isobutyl bromide and then reacting with itaconic acid diperoxybutyl ethyl ester. Further, the preparation method of the modified cardanol comprises the following steps: Adding cardanol, epichlorohydrin and tetrabutylammonium bromide into a reactor, heating to 90-100 ℃, stirring and reacting for 3-4 hours, then cooling to 40-50 ℃, dropwise adding 10% sodium hydroxide aqueous solution into the system, adjusting the pH value to 7-8, adding ethyl acetate into the system, stirring for 0.5-1 hour, separating out an organic layer, washing the organic layer with saturated saline water, drying the organic layer with anhydrous sodium sulfate, and removing the solvent by rotary evaporation to obtain the epoxy cardanol; in the steps, the phenolic hydroxyl group of the cardanol and the epoxy group of the epichlorohydrin are subjected to ring opening etherification reaction, and then the epoxy group is introduced into cardanol molecules through intramolecular ring closure, so that the epoxy cardanol with the epoxy group is generated. Adding epoxy cardanol and hydrogen-containing silicone oil to toluene solvent under the protection of nitrogen gas, heating to 90-100 ℃, dropwise adding an isopropanol solution of chloroplatinic acid to the toluene solvent, heating to 105-115 ℃, reacting for 5-7h, cooling to room temperature after the reaction is finished, adding deionized water with the same volume, washing for 3-4 times, standing for layering after each washing, separating an organic layer, drying the obtained organic layer with anhydrous sodium sulfate for 12-14h, filtering, concentrating, precipitating, washing and drying to obtain the modified cardanol. In the steps, unsaturated double bonds in the epoxy cardanol molecules and active silicon hydrogen bonds in the terminal hydrogen-containing silicone oil undergo a hydrosilylation reaction under the action of a chloroplatinic acid catalyst, and a silicon-containing chain segment is grafted onto the cardanol molecules through stable C-Si bonds, so that the modified cardanol containing the organic silicon chain segment is obtained. Further, in the first step, the dosage ratio of cardanol, epichlorohydrin, tetrabutyl