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JP-7855351-B2 - Novel two-component outer coating containing polyaspartate ester

JP7855351B2JP 7855351 B2JP7855351 B2JP 7855351B2JP-7855351-B2

Inventors

  • グレスタ－フランツ，ドルタ
  • ウェイカード，ヤン
  • ヴィンターマンテル，マティアス
  • レイエ，ロベルト
  • シュットラー，トマス

Assignees

  • コベストロ、ドイチュラント、アクチエンゲゼルシャフト

Dates

Publication Date
20260508
Application Date
20200220
Priority Date
20190222

Claims (12)

  1. A process for producing a two-component coating composition (2C coating composition) comprising the following, a) At least one polyaspartate ester-containing component A, b) at least one polyisocyanate component B, c) Optionally, one or more components C that are reactive to isocyanate groups, unlike A. d) at least one inorganic and/or organic pigment , and which may contain other auxiliary agents and additives (component D2), Here, component A corresponds to a composition containing the following: One or more polyaspartate esters of general formula (I) [In the formula, X is an m-valent organic group, optionally containing one or more heteroatoms, having an amino group bonded (cyclo)aliphatic or aromaticaliphatic, obtainable by removing a primary amino group from a corresponding polyamine, and having a molecular weight in the range of 60 to 6000 g/mol.] Furthermore, it may contain additional functional groups that are reactive with respect to the isocyanate group and/or inert at temperatures up to 100°C. R1 and R2 are identical or different organic groups, each having 1 to 18 carbon atoms. m is an integer greater than 1, and One or more polyaspartic acid esters having a primary amino group of general formula (II) [In the formula, n is m-1, and X and R1 and R2 are the same as above]. and, The dialkyl fumarate is present in component A in an amount of 0.01% to 1.2% by weight based on the total weight of component A. Furthermore, the proportion of the compound of formula (II) is 4% or more and 20% or less based on the area determined by GC (measured as area %) of the gas chromatogram, and here, the sum of the areas of the two compounds of general formulas (I) and (II) determined by GC is 100%. Here, the amount of dialkyl fumarate is reduced by distillation. The aforementioned process.
  2. The process according to claim 1, characterized in that dialkyl fumarate is present in component A in an amount of 0.01% to 1% by weight, based on the total weight of component A.
  3. The process according to claim 1, characterized in that dialkyl fumarate is present in component A in an amount of 0.01% to 0.1% by weight, based on the total weight of component A.
  4. The process according to any one of claims 1 to 3, wherein the proportion of the compound of formula (II) is 15% or less of the area measured by GC.
  5. A method for manufacturing a coating on a substrate, including the following steps: i) Apply the two-component coating composition obtained by the process described in any one of claims 1 to 4 to at least a portion of the substrate to be coated, and ii) cure the coating composition from step i).
  6. A substrate having a coating thereon, wherein the coating comprises a cured two-component coating composition as defined in any one of claims 1 to 4 .
  7. A method for manufacturing a coating on a substrate according to claim 5, characterized in that the coating is a top coat.
  8. The substrate according to claim 6, characterized in that the coating is a top coat .
  9. Use of a two-component coating composition (2C coating composition) obtained by a process according to any one of claims 1 to 4 for manufacturing a coating, Herein, the use is such that the coating is used in the field of corrosion protection or general industrial coating, or as a coating for ACE (agricultural, construction and earthwork equipment).
  10. The method according to claim 5 or 7, wherein the coating is used in the field of corrosion protection or general industrial coating, or as a coating for ACE (agricultural, construction and earthworks) .
  11. The substrate according to claim 6 or 8, wherein the coating is used in the field of corrosion protection or general industrial coating, or as a coating for ACE (agricultural, construction and earthworks) .
  12. Use of a two-component coating composition (2C coating composition) obtained by the process described in any one of claims 1 to 4 for manufacturing a gloss-stable coating.

Description

This invention relates to a two-component topcoat system containing a polyaspartate ester containing only a small amount of dialkyl fumarate, a method for producing the same, its use in the production of coatings, particularly for corrosion protection, and its application in the fields of ACE (agriculture, construction, and earthworks), and its use in substrates coated therewith. Two-component (2C) coating compositions containing a binder that is reactive to isocyanate groups, particularly a polyisocyanate component combined with a polyhydroxyl component, have long been known. They are suitable for producing high-quality coatings that are hard, elastic, abrasion-resistant, solvent-resistant, and, above all, weather-resistant. Within the scope of this 2C polyurethane coating technology, certain ester-containing secondary polyamines have been established in recent years. So-called polyaspartic acid esters or polyaspartate salts, when combined with paint polyisocyanates, are particularly suitable as binders in low-solvent or solvent-free (high-solids content) coating compositions, enabling rapid curing of coatings at low temperatures. In addition to the rapid curing of these coatings as described above, the use of such polyaspartate esters in topcoats allows for a reduced-layer structure, which is highly attractive for use in the field of topcoats. However, in the fields of corrosion protection and ACE (agricultural, construction, and earthworks), conventional polyaspartate-based topcoats have not been established due to their loss of gloss. Therefore, there has long been a demand in the market for colored polyaspartate-based topcoats with improved gloss retention. The use of polyaspartate esters in 2C coating compositions, either alone or in mixtures with further components reactive to isocyanate groups, is described, for example, in EP0403921, EP0639628, EP0667362, EP0689881, US5214086, EP069696, EP0596360, EP0893458, DE19701835, EP0470461, WO15130501, WO15130502, and US5243012. The preparation of amino-functional aspartates is known in itself. Synthesis is carried out by the addition of a primary polyamine to the activated carbon-carbon double bond of a vinyl carbonyl compound, such as maleic acid or fumarate esters, which is well described in the literature (Houben-Weyl, Meth. d. Org. Chemie vol. 11/1, 272 (1957), Usp. Khim. 1969, 38, 1933). If only one amino group of the polyamine reacts with the double bond of the vinyl carbonyl compound, this reaction can result in the formation of a polyaspartate ester having a primary amino group as a byproduct. In commercially available polyaspartates, maleic acid esters are used as the vinyl carbonyl compound. During the preparation of polyaspartates based on maleic acid esters, retro-Michael addition may occur as a further undesirable side reaction, where the elimination of the polyamine results in the formation of a dialkyl fumarate as a byproduct. Therefore, a typical method for producing polyaspartate esters requires a storage period of 4 to 6 weeks after the majority of the reactants have reacted with each other. During this time, the product undergoes so-called maturation, which is evident in the stabilization of viscosity. During this period, the conversion rate continues to increase, and the dialkyl fumarate content also decreases. This storage period of several weeks incurs considerable logistical costs during production. The product is not shipped to the customer until the end of the storage period, but it still contains a considerable amount of dialkyl fumarate, which can cause severe sensitization. After maturation, the polyaspartate esters thus prepared typically still contain residual amounts of fumarate ranging from 3 to 20 weight percent. EP0403921EP0639628EP0667362EP0689881US5214086EP069696EP0596360EP0893458DE19701835EP0470461WO15130501WO15130502US5243012 Houben-Weyl, Meth. d. Org. Chemie vol. 11/1, 272 (1957), Usp. Khim. 1969,38,1933 The present invention relates to a two-component coating composition (2C coating composition) comprising the following: a) At least one polyaspartate ester-containing component A, b) at least one polyisocyanate component B, c) Optionally, one or more components C that are reactive to isocyanate groups, unlike A. d) at least one inorganic and/or organic pigment, preferably in a proportion of at least 3% by weight (≥3% by weight) based on the total weight of the two-component composition (component D1), Optionally, other auxiliary agents and additives (component D2). In the context of the present invention, polyaspartate ester-containing component A is One or more polyaspartate esters of general formula (I) [wherein X is an m-valent organic group, optionally containing one or more heteroatoms and having an amino group bonded to a (cyclo)aliphatic or aromaticaliphatic group, which can be obtained by removing a primary amino group from a corresponding polyamine, and having a molecular weight in the range of 60 to 6000 g/m