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KR-20260065947-A - Polyisocyanate composition and coating layer having enhanced chemical resistance

KR20260065947AKR 20260065947 AKR20260065947 AKR 20260065947AKR-20260065947-A

Abstract

The present invention relates to the field of polyisocyanate compositions and provides a polyisocyanate composition and a coating layer having improved chemical resistance. A coating layer formed from a polyurethane paint composition based on the polyisocyanate composition provided in the present invention has significantly improved chemical resistance and can possess comprehensive performance such as good hardness and flexural strength. The polyisocyanate composition is derived from at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates, and among the compounds included in the polyisocyanate composition, at least some of the said compounds have an isocyanurate group and at least some of the said compounds have at least one thioallophanate group; in the polyisocyanate composition, the equivalent ratio of the thioallophanate group to the isocyanurate group is greater than 0 and less than or equal to 0.3.

Inventors

  • 장 샤오펑
  • 왕 단
  • 천 뤼
  • 왕 위치
  • 시 빈
  • 상 용화
  • 위 타오
  • 천 리장

Assignees

  • 완후아 케미컬 그룹 코., 엘티디

Dates

Publication Date
20260511
Application Date
20231113

Claims (11)

  1. A polyisocyanate composition, wherein the polyisocyanate composition is derived from at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates, and wherein, among the compounds included in the polyisocyanate composition, at least some of the compounds have an isocyanurate group and at least some of the compounds have at least one thioallophanate group, A polyisocyanate composition characterized in that, in the above polyisocyanate composition, the equivalent ratio of the thioallophanate group to the isocyanurate group is greater than 0 and less than or equal to 0.3.
  2. In paragraph 1, A polyisocyanate composition characterized in that, in the above polyisocyanate composition, the equivalent ratio of the thioallophanate group to the isocyanurate group is 0.005 to 0.250, and more preferably 0.005 to 0.100.
  3. In paragraph 1 or 2, A polyisocyanate composition characterized in that, based on the total amount of isocyanurate groups, thioallophanate groups, and optionally present iminooxadiazindione groups, biuret groups, uretdione groups, thiocarbamate groups, and uretonimine groups in the above polyisocyanate composition, the content of the isocyanurate groups is 90 mol% or more and less than 100 mol%.
  4. In any one of paragraphs 1 through 3, The polyisocyanate composition can be obtained by reacting a reactant comprising the diisocyanate and a thiol compound, wherein the thiol compound is selected from at least one thiol compound that is a straight chain or a branched chain and is optionally substituted; preferably, the group in the thiol compound that is reactive with the isocyanate group is a thiol group.
  5. In paragraph 4, The above thiol compound has 1 to 20 carbon atoms, preferably 6 to 12 carbon atoms; Preferably, the thiol compound is one or more of monothiols and polythiols, and more preferably, monothiols; More preferably, the polyisocyanate composition is characterized in that the thiol compound is one or more selected from 1-hexanethiol, 2-hexanethiol, 3-hexanethiol, 1-methylpentan-2-thiol, 3,3-dimethylbutan-1-thiol, 2-ethyl-butan-1-thiol, 1-methyl-1-pentanethiol, 3-methylpentan-2-thiol, 1-heptanethiol, 2-heptanethiol, 1-octanethiol, 2-octanethiol, 2-ethyl-1-hexanethiol, 1-nonanthiol, 2-nonanthiol, 1-decanethiol, 3-decanethiol, 1-undecanthiol, undec-10-en-1-thiol, 1-dodecanethiol, 2-dodecanethiol, and tert-dodecanethiol.
  6. In any one of paragraphs 1 through 5, The above diisocyanate is one or more selected from hexamethylene diisocyanate, pentamethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 2,4,4-trimethyl-1,6-hexane diisocyanate, 2,2,4-trimethyl-1,6-hexane diisocyanate, 4-isocyanatomethyl-1,8-octane diisocyanate, 3-isocyanatomethyl-1-methylcyclohexyl isocyanate, 4-isocyanatomethyl-1-methylcyclohexyl isocyanate, isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, and 1,4-bis(isocyanatomethyl)cyclohexane, and is preferably one or two selected from hexamethylene diisocyanate and pentamethylene diisocyanate. Polyisocyanate composition.
  7. In any one of paragraphs 4 through 6, The above reaction is carried out in the presence of a catalyst; the amount of said catalyst used is preferably 0.001 wt% to 0.1 wt% of the diisocyanate used in the preparation of said polyisocyanate composition, and more preferably 0.005 wt% to 0.05 wt%; Preferably, the catalyst is one or more selected from quaternary ammonium hydroxide, quaternary ammonium carboxylate, a compound containing a silylamino group, a tertiary amine compound, and a Mannich base compound; Additionally, the quaternary ammonium hydroxide is one or more selected from, for example, tetramethylammonium hydroxide, trimethylbenzylammonium hydroxide, tetraethylammonium hydroxide, dimethylethylcyclohexylammonium hydroxide, and hydrates thereof; Additionally, the quaternary ammonium carboxylate is, for example, tetramethylammonium hydroxide-2-ethylhexanoate, tetramethylammonium hydroxide-octanoate, trimethylbenzylammonium hydroxide-2-ethylhexanoate, trimethylbenzylammonium hydroxide-octanoate, tetramethylammonium hydroxide-formate, tetramethylammonium hydroxide-acetate, tetramethylammonium hydroxide-pivalate, trimethylbenzylammonium hydroxide-pivalate, tetramethylammonium hydroxide-decanoate, trimethylbenzylammonium hydroxide-decanoate, tetramethylammonium hydroxide-tetradecanoate, tetramethylammonium hydroxide-2-ethylhexanoate, tetramethylammonium One or more selected from hydroxide-octanoate, trimethylbenzylammonium hydroxide-2-ethylhexanoate, and trimethylbenzylammonium hydroxide-octanoate; Additionally, the compound containing the silylamino group is one or more selected from, for example, hexamethyldisilazane, silylamine, and heptamethyldisilazane; Additionally, the tertiary amine compound is one or two selected from, for example, triethylamine and tripropylamine; Additionally, the polyisocyanate composition is characterized in that the above-mentioned Mannich base compound is, for example, tris(N,N-dimethylaminomethyl)phenol.
  8. In any one of paragraphs 4 through 7, The reaction temperature of the above reaction is 10°C to 150°C, preferably 30°C to 79°C, and more preferably 45°C to 75°C; and/or, a polyisocyanate composition characterized in that the reaction termination point of the above reaction is within the range of 30% to 50% of the NCO% value of the reaction system.
  9. Use of a polyisocyanate composition according to any one of claims 1 to 8 as a crosslinking agent in a paint composition.
  10. In a two-component polyurethane paint composition, A two-component polyurethane paint composition comprising component A and component B, wherein component A comprises at least one polyisocyanate composition according to any one of claims 1 to 8, and component B comprises at least one binder that reacts with isocyanate groups.
  11. In a coating layer having improved chemical resistance, The above coating layer is a coating layer having improved chemical resistance, characterized by being obtained by applying a polyurethane paint composition according to claim 10 to the surface of a substrate.

Description

Polyisocyanate composition and coating layer having enhanced chemical resistance The present invention relates to a polyisocyanate composition, and specifically to a polyisocyanate composition and a coating layer having improved chemical resistance. Aliphatic/alicycloal polyisocyanates possess excellent physical properties such as weather resistance, wear resistance, and corrosion resistance, and are widely applied in the paint, adhesive, and elastomer industries. They are particularly widely used in the paint industry and include the most widely used isocyanate-containing polyisocyanate curing agents. Aliphatic polyisocyanate compositions containing isocyanurate groups possess advantages such as excellent resistance to yellowing, low free monomer content, saturated vapor concentrations significantly lower than occupational safety limits, high functionality, and high subsequent crosslinking density. Currently, numerous literatures and patents report methods for preparing isocyanurate-containing polyisocyanate compositions using aliphatic and alicyclic diisocyanates under catalytic action (e.g., J. Prakt. Chem. 336(1994)185-200, US4040992, US4288586, US4419513, US673062, US6800714, US7001973, etc.). Considering the diversity of subsequent application formulations, it is often necessary to use a curing agent together with a high-hydroxy resin to improve the crosslinking density, mechanical properties, and chemical resistance of the coating film. However, due to the rigid structure of the isocyanurate ring itself, it has poor compatibility with high-hydroxy resin formulations, causing the composition to become diluted or cloudy and exhibit a blue light, which affects the gloss of the formed coating film. Currently, the main method to improve the compatibility of polyisocyanate compositions is alcohol modification, that is, introducing alcohol into the reaction system. U.S. Patent US460441 reports a polyisocyanate composition containing a urethane-modified isocyanurate obtained by mixing and polymerizing a polyisocyanate with a diol or polyol. US Patent US6420508 reports a method for synthesizing a polyisocyanate composition with excellent compatibility through a two-step method in which a polyisocyanate is first self-polymerized and then alcohol modified. Chinese patent CN1074065 reports on the preparation of a polyisocyanate composition having good compatibility by controlling the isocyanurate trimer content to 59% or less and controlling the equivalent ratio of the allophanate group to greater than 0 and 0.19 or less. Although alcohol modification can resolve some compatibility issues, compositions obtained through this route often have disadvantages, such as a low isocyanate concentration which increases the amount of curing agent used and poor chemical resistance after film formation. The present invention provides a polyisocyanate composition and a coating layer having improved chemical resistance. A coating layer formed from a polyurethane paint composition based on the polyisocyanate composition provided in the present invention has significantly improved chemical resistance and can possess good hardness and flexural strength. To achieve this purpose, the present invention provides the following technical solution. One aspect of the present invention provides a polyisocyanate composition, wherein the polyisocyanate composition is derived from at least one diisocyanate selected from aliphatic diisocyanates and alicyclic diisocyanates, and among the compounds included in the polyisocyanate composition, at least some of the compounds have an isocyanurate group, and at least some of the compounds have at least one thioallophanate group; In the above polyisocyanate composition, the equivalent ratio of the thioallophanate group to the isocyanurate group is greater than 0 and less than or equal to 0.3, for example, 0.001, 0.003, 0.005, 0.007, 0.010, 0.015, 0.020, 0.025, 0.030, 0.050, 0.070, 0.100, 0.150, 0.200, 0.250, 0.270, 0.300, etc. The inventors have discovered that by controlling the equivalent ratio of the thioallophanate group in the polyisocyanate composition to be greater than 0 and less than or equal to 0.3, it is advantageous to improve the chemical resistance of the polyurethane paint coating layer based on the polyisocyanate composition and to possess good hardness and flexural strength. Preferably, the equivalent ratio of the thioallophanate group to the isocyanurate group in the polyisocyanate composition is 0.005 to 0.250. More preferably, the equivalent ratio of the thioallophanate group to the isocyanurate group is 0.005 to 0.100, and by controlling the equivalent ratio of the polyisocyanate composition to a preferred range, the performance of the coating layer of the obtained polyurethane paint is further improved, and it is advantageous to have even better chemical resistance, hardness, and flexural strength. In the present invention, the isocyanurate group refers to a group having the fol