Search

EP-3831835-B1 - AN ENVIRONMENT-FRIENDLY GAS-SENSITIVE COATING FOR VOLATILE ACIDS AND THE PREPARATION METHOD THEREOF

EP3831835B1EP 3831835 B1EP3831835 B1EP 3831835B1EP-3831835-B1

Inventors

  • LU, HAIFENG
  • WU, Lianfeng
  • WANG, XIANMING
  • FENG, Shengyu

Dates

Publication Date
20260506
Application Date
20200603

Claims (7)

  1. An environment-friendly gas-sensitive coating for volatile acids, characterized in comprising components in parts by mass as follows: 50 to 100 parts of strong acid resistant resin, 1 to 30 parts of special color-changing agent A, 0.5 to 5 parts of auxiliary color-changing component, 0 to 20 parts of fillers, 0 to 20 parts of auxiliaries and 0 to 300 parts of solvent; wherein the special color-changing agent A is a substance obtained by treating the white carbon black with the compound B; wherein the compound B has the structural characteristics as follows: where R' is a variety of bridging organic groups that can connect benzene rings to silicon atoms; R" is a variety of organic groups that can be separated in the form of HOR" structure; and wherein the auxiliary color-changing component is a variety of organic dyes or inorganic dyes; wherein the strong acid resistant resin is a variety of strong acid-resistant two-component solvent-free resins; wherein strong acids are all acids or acidic gases with pH < 3, including hydrofluoric acid (liquid or steam), sulfuric acid, fluosilicic acid, hydrochloric acid, nitric acid, chlorine, hydrobromic acid, trifluoroacetic acid, perchloric acid, glacial acetic acid and other acids or acid vapors.
  2. The environment-friendly gas-sensitive coating for volatile acids according to Claim 1, wherein the strong acid resistant resin is solvent-free epoxy resin, solvent-free phenolic epoxy resin, solvent-free polyurethane resin or solvent-free polyurea resin.
  3. The environment-friendly gas-sensitive coating for volatile acids according to Claim 1, wherein the auxiliary color-changing component is modified polyaniline, medium chrome yellow, permanent yellow, fast yellow, zinc yellow, lemon yellow, iron oxide brown or iron oxide yellow; the fillers are titanium dioxide, mica powder, aluminium hydroxide, magnesium hydroxide, silica powder, white carbon black, talcum powder, nano calcium carbonate or barium sulfate; and the auxiliaries are flatting agent, de-foaming agent, dispersing agent or anti-settling agent.
  4. The environment-friendly gas-sensitive coating for volatile acids according to Claim 1, wherein the mass ratio of the strong acid resistant resin, special color-changing agent A, auxiliary color-changing component, fillers and auxiliaries is 100: 1-30: 0.5-5: 0-20: 0-40; and is preferred to be 100: 5-20: 10-20: 15-30: 1-5.
  5. The environment-friendly gas-sensitive coating for volatile acids according to Claim 1, wherein the environment-friendly gas-sensitive coating for volatile acids also includes 25 parts of curing agent.
  6. The environment-friendly gas-sensitive coating for volatile acids according to Claim 5, wherein the curing agent is isocyanate curing agent or polyamide resin.
  7. The environment-friendly gas-sensitive coating for volatile acids according to Claim 1, wherein the process of treating the white carbon black with compound B is as follows: mixing the compound B, the white carbon back and the solvent evenly and heat the mixture up for solvent refluxing; holding the reaction for 2-4 hours until the refluxing stops; then, reducing the pressure and removing the solvent through distillation to obtain the special color-changing agent A.

Description

Technical Field The invention relates to the preparation of an environment-friendly gas-sensitive coating for volatile acids, and belongs to the field of comprehensive utilization of chemical products. Background Art Strong acids, such as concentrated sulfuric acid, hydrofluoric acid, nitric acid and hydrochloric acid, have contributed a lot to the development of the national economy considering their widespread applications in petroleum alkylation, fluorine chemical industry, ore floatation, pulp and papermaking industry, semiconductor industry and other chemical industry production fields. Currently, the petrochemical industry uses mainly two alkylation processes, respectively hydrofluoric acid method and sulfuric acid method. Among them, the hydrofluoric acid method uses the hydrofluoric acid as a catalyst to have industrial isooctane (namely alkylate oil) synthesized from isobutane and butane. The alkylate oil prepared in this way is a mixture of heterogeneous alkanes with not only good anti-detonating quality and unleaded gasoline octane value up to above 94, but also ideal volatility and clean combustion performance, and thus is an ideal component for automotive gasoline. However, in the hydrofluoric acid alkylation process, the hydrofluoric acid is one of the most important materials. The hydrofluoric acid pipeline flange joints of the alkylation until are all potential leakage points, and will cause great harm in case of leakage. The highly corrosive hydrofluoric acid can be very destructive to the silicon-containing materials (glass and cement, etc.) and various metal equipment; additionally, the hydrofluoric acid is highly volatile, with minimal taste and colorless when exposed in the air; its exposure is difficult to be observed, but can cause serious and incurable damages to people and animals and even endanger their lives. Therefore, it is of great importance to detect the hydrofluoric acid leakage as early as impossible so as to minimize the damages caused thereby. The hydrofluoric acid color-changing warning coating is a special purpose coating that can be used to detect the leakage of hydrofluoric acid/hydrogen fluoride vapor, and also a gas-sensitive coating against volatile acids. It acts as a preservative under normal circumstances when applied to the hydrofluoric acid pipeline flanges or valves, but shows significant and long-lasting color changes within a short time in case of leakage of the hydrofluoric acid, so that the operators can be warned to deal with the leaking points timely and avoid major safety accidents. Similar to hydrofluoric acid, the other industrial acids, such as hydrochloric acid, nitric acid and glacial acetic acid, also have serious problems in use, including volatile, easy to leak, colorless, and hazardous. Therefore, it is urgent to develop a gas-sensitive coating for such volatile acids. As solvent based coatings release volatile organic compounds in the coating process and pollute the air, the development of environment-friendly solvent-free gas-sensitive coatings is more in line with the needs of social development. Chinese Patent Document CN106905833A (Application number: 201710218911.5) has disclosed an environment-friendly chromotropic interior wall coating and the preparation method thereof. The paint comprises the following components: polyurethane resin material, ethanol, antishrinking agent, and triphenylmethane dyes or fluorane dyes. The coating can effectively warn the superacid or superbasic environment which is harmful to human health, so that people can keep the air circulation of the working environment in time, and take active protective measurements. However, the polyurethane resin used by the coating is not resistant to strong acids, and the coating will decompose and fall off when encountering leakage of strong acids, so this coating cannot well protect the equipment. Chinese Patent Document CN108530053A (Application number: 201810279464.9) has disclosed a pH-sensitive allochroic inorganic material and the preparation method thereof. By mixing the prepared allochroic powder with other resin solutions or emulsion, a pH-sensitive allochroic paint or film material can be obtained. However, the pH-sensitive allochroic inorganic material prepared in the invention needs complicated preparation processes and high energy consumption. Although researches on acid warning coatings have stared earlier overseas, only a few companies have developed such coatings successfully and applied them widely in petrochemical units, fluorine chemical industry and semiconductor industry. Considering the difficulty of development, there are few researches on acid warning coatings in China. China once developed a "hydrogen fluoride indicating paint" in the 1990s, but compared to foreign products, it still had a lot of problems, including non-obvious color change, long color-changing time, irreversible color changing (single use only) and the like. Therefore, it failed to