The use of rhamnolipids and / or sophorolipids in coating compositions to obtain a uniform color appearance of the dried coating film and / or to improve occupational safety in the manufacture of coating compositions.

Abstract

To increase occupational safety and provide improved homogeneous colour appearance of a dry coating film in the production of a coating composition.SOLUTION: The present invention discloses the use of rhamnolipids and / or sophorolipids in coating compositions, for improved speed of wetting of pulverulent formulation constituents in the coating compositions, which leads to a reduction in dust nuisance during incorporation of the pulverulent formulation constituents, resulting in increased occupational safety in the production of the coating compositions, providing the improved homogeneous colour appearance of a dry coating film with regard to difference in hue, ascertained from the ΔE and visual assessment.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the use of rhamnolipids and / or sophorolipids in coating compositions to obtain a uniform color appearance of the dried coating film and / or to improve occupational safety in the manufacture of the coating composition. [Background technology]

[0002] Coatings are applied to surfaces for decorative and / or protective purposes. Many coating applications involve formulations containing particles such as pigments and / or fillers.

[0003] Pigments are coloring substances that exist in an insoluble dispersed form within the application medium. Application mediums include, for example, paints, coating materials, pigment preparations, printing inks, or organic solvents and other formulations into which pigments are incorporated. Typically, crude pigments produced by synthesis are used in ground or pulverized form. For example, so-called dry and wet pulverization methods are used. However, particles with a particularly high tendency to aggregate require stabilization.

[0004] Pigments, being crucial components of a coating, determine its appearance and physicochemical properties; therefore, pigment stabilization is extremely important in the coating industry. For them to function optimally in a coating, they must be uniformly and finely dispersed in the varnish during the dispersion process. Maintaining this state throughout manufacturing, storage, processing, and subsequent film formation requires stabilizing the dispersion. Recombination of primary particles and aggregates can lead to, for example, insufficient color depth, pigment lifting, and / or reduced color reproducibility.

[0005] Commercial paint formulations are only single-colored in some cases. In most cases, they contain a mixture of two or more different pigments. Even in such systems, all pigments must be thoroughly moistened, undone as much as possible, and uniformly dispersed throughout the paint film. However, if this mixture is disrupted by pigment separation, the paint's hue changes. This defect is called "floating."

[0006] One cause of pigment separation is the flow phenomenon of the dried paint film. During the drying stage of the paint film, the solvent needs to be transported from the lower coating layer to the surface. In the process of evaporation, the density of the residue increases and as a result it settles. Furthermore, a cooling effect occurs during the evaporation process, and the surface tension changes. All of this leads to the formation of vortices, which can manifest as roughly uniform hexagonal cells (called Bénard cells). The coating material rises at the center of the cell, then disperses across the entire surface, and flows backward downward at the cell boundaries. These cellular flows have long been known, not only in paints. In colored systems, the pigments are also involved in these vortices, and assuming that the mobilities of various pigments are similar, they are also transported in very similar ways within the vortices and do not separate. However, if there are clear differences in the mobilities of the pigments, their transport characteristics will also differ, and separation may occur.

[0007] As a result, for example, the dried coating may have an uneven appearance.

[0008] Rob-out tests, such as measuring the hue difference (ΔE) between a rubbed and unrubbed surface, are standard methods for testing these mottling or aggregations. These are described, for example, in Non-Patent Documents 1 and 2. These effects negatively impact the uniform color appearance of a dried coating. Furthermore, these undesirable effects on a dried coating are often visually determined under standard lighting conditions.

[0009] In the context of this specification, the terms application medium, coating system, coating composition, paint formulation, and paint medium are used synonymously.

[0010] Prior art discloses polymer wetting agents and dispersants that first contain pigment-affinity groups, such as carboxyl functional groups, amino functional groups, or phenyl functional groups, and secondly contain media-soluble side chains. Ideally, the pigment-affinity groups have abrupt orientation to the pigment surface and high durability. The side chains ensure compatibility with the dispersion or coating medium and steric stabilization of the dispersed phase.

[0011] Some publications also mention biosurfactants as dispersants, defoamers, wetting agents, or emulsifiers for paints and coatings. Representative examples of these biosurfactants are rhamnolipids and sophorolipids. These lipids are currently produced in various yeasts, particularly wild-type isolates of Candida bombicola.

[0012] Patent Document 1 describes a coating composition comprising, for example, a binder, a biocide, and a dispersion of a biosurfactant composed of rhamnolipids and sophorolipids. Patent Document 2 discloses a similar composition to which isothiazolone biocide is specifically added. Both documents disclose the synergistic biocide effect of rhamnolipids and sophorolipids and biocides.

[0013] When finely ground particles are incorporated into the application medium, dust contamination can occur at the production site. In this process, as is well known, for example, an employee opens a bag containing the particles and pours the contents into an open container that has been pre-filled with the application medium. In large-scale production plants, particles stored in silos are added to the application medium. Then, a stirring operation is initiated. It is also known that stirring may be performed during the addition of particles. This stirs up a large amount of dust as long as the pigment is present in powder form on the surface of the liquid application medium. The fine particles can enter the tiny alveoli of the lungs, where they can cause illness. For this reason, many companies install exhaust hood systems to minimize employees' exposure to dust. In addition, employees need to wear respiratory masks frequently. This means that heat accumulates under the respiratory equipment. [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] European Patent Publication No. 3006505 [Patent Document 2] European Patent Publication No. 2 847 285 [Non-patent literature]

[0015] [Non-Patent Document 1] Groteklaes M, Rub-out-Effekt, RD-18-01991 (2005) [Non-Patent Document 2] Bockler F., Dill B., Eisenbrand G., Faupel F., Fugmann B., Gamse T., Matissek R., Pohnert G., Ruhling A., Schmidt S., Sprenger G., ROMPP [online], Stuttgart, Georg Thieme Verlag, [November 2021] https: / / roempp.thieme.de / lexicon / RD-18-01991 [Overview of the Initiative] [Problems that the invention aims to solve]

[0016] Therefore, it would be desirable to identify substances that reduce dust contamination in the manufacture of coating compositions. It would also be desirable to use such substances in the coating compositions to achieve a uniform color appearance of the dried coating film without impairing properties such as hue and color locus. [Means for solving the problem]

[0017] Surprisingly, the use of rhamnolipids and / or sophorolipids in coating compositions is suitable for improving the wetting rate of powdery formulation components in such compositions, thereby reducing the dust nuisance when incorporating the powdery formulation components, and as a result, enhancing the labor safety in the production of coating compositions and ensuring or improving the maintenance of a uniform color appearance of the dry coating film has been found.

[0018] The dry coating film has been further found to have an improved uniform color appearance with respect to the color difference confirmed from ΔE and visual evaluation compared to a conventional coating film不含 rhamnolipids and / or sophorolipids as described below by the use of rhamnolipids and / or sophorolipids.

[0019] A further advantage is that the time taken to introduce the particles into the application medium is shortened, which means the optimization of the process time required.

[0020] Powdery formulation components, solids, pigments, particles are used as synonyms.

[0021] The coating composition is preferably a preparation for various application fields to be applied to a substrate to be coated by an application method (e.g., spraying, dipping, rolling, or painting) and various printing methods.

[0022] Examples of coating materials in the context of this specification include paints, coating materials, printing inks, and other coating materials (e.g., solvent-based or aqueous coatings and solvent-free coatings, powder coatings, UV-curable coatings, low-solids, medium-solids and high-solids coatings, automotive coatings, woodworking coatings, baked coatings, two-component coatings, metal coating materials, and toner compositions). Further examples of coating materials are described in "Bodo Muller, Ulrich Poth, Lackformulierung und Lackrezeptur, Lehrbuch fur Ausbildung und Praxis [Coating Formulation and Coating Composition, Textbook for Training and Practice], Vincentz Verlag, Hanover (2003), 73-1996" and "PGGarrat, Strahlenhrtung [Radiative Curing], Vincent Verlag, Hanover (1996)".

[0023] Paints and coating materials include interior paints, exterior paints, architectural paints, floor coatings, woodworking paints, industrial paints, OEM (original equipment manufacturer) or refinishing paints for automobiles, primers, primer services, base coats, and top coats.

[0024] Examples of printing inks and / or varnishes in the context of this specification include solvent-based or aqueous printing inks, flexographic printing inks, intaglio printing inks, letterpress or relief printing inks, offset printing inks, lithographic printing inks, packaging printing inks, screen printing inks, inkjet printer inks, inkjet inks, and printing varnishes such as overprint varnishes. Further printing ink and / or varnish formulations are described in "EWFlick, Printing Ink and Overprint Varnish Formulations - Recent Developments, Noyes Publications, Park Ridge NJ (1990)" and subsequent editions.

[0025] The coating composition preferably includes a solid selected from the group consisting of fillers, pigments, dyes, fluorescent whitening agents, ceramic materials, and magnetic materials.

[0026] Examples of pigments are selected from a group of inorganic pigments such as carbon black, titanium dioxide, zinc oxide, Prussian blue, iron oxide, cadmium sulfide, and chromium pigments (e.g., chromates, molybdates, and chromate and sulfate mixtures of lead, zinc, barium, calcium, and mixtures thereof). Further examples of inorganic pigments are specified in the book "H. Endriss, Aktuelle anorganische Bunt-Pigmente [Inorganic Colour Pigments Today], Vincentz Verlag, Hannover (1997)".

[0027] Examples of organic pigments are selected from the group consisting of azo pigments, diazo pigments, condensed azo pigments, naphthol pigments, metal complex pigments, thioindigo pigments, indanthron pigments, isoindanthron pigments, ansanthron pigments, anthraquinone pigments, isodibenzantrone pigments, triphendioxazine pigments, quinacridone pigments, perylene pigments, diketopyrrolopyrrole pigments, and phthalocyanine pigments. Further examples of organic pigments are specified in the book "W. Herbst, K. Hunger, Industrial Organic Pigments, VCH, Weinheim (1993)".

[0028] Examples of fillers are selected from the group including talc, kaolin, silica, barite and lime, ceramic materials (e.g., aluminum oxide, silicates, zirconium oxide, titanium oxide, boron nitride, silicon nitride, boron carbide, mixed aluminum silicon nitride, and metallic titanates), magnetic materials (e.g., magnetic oxides of transition metals such as iron oxides, cobalt-doped iron oxides, and ferrites), and metals (e.g., iron, nickel, cobalt, and their alloys).

[0029] Those skilled in the art will notice that such coating compositions may contain further components. As liquid media, depending on the binder used, they may also contain organic solvents (e.g., acetates such as butyl or ethyl acetate, hydrocarbons such as petroleum extracts of various boiling point ranges, alcohols, ethers, glycols, and glycol ethers) and / or water, which are also known in the prior art.

[0030] Commercially available binders can be used. Alkyd binders, acrylate binders, styrene-acrylate binders, epoxy binders, polyvinyl acetate binders, polyester binders, or polyurethane binders can be used preferentially. All types of curing are possible, for example, oxidative drying, physical drying, self-crosslinking, UV or electron beam curing, or crosslinking by baking.

[0031] The coating composition is thought to include further additives, for example, preferably wetting agents, dispersants, rheological additives, leveling aids, or defoaming agents.

[0032] Those skilled in the art recognize that the preparation of coating compositions containing particles can be achieved, for example, by the use of pigment concentrates, color pastes, pigment pastes, or liquid formulations of particles. However, mill bases can also be prepared for timely use in the preparation of coating compositions.

[0033] Therefore, the present invention also preferably provides the use of rhamnolipids and / or sophorolipids in pigment concentrates, color pastes, pigment pastes, or particle or mill-based liquid formulations.

[0034] Rhamnolipids and sophorolipids are surfactants that can be prepared by fermentation.

[0035] Rhamnolipids are composed of 1-2 rhamnose units and 1-3 mostly β-hydroxylated fatty acids. The fatty acids may or may not be saturated.

[0036] Variations in the chain length and number (congeners) of the fatty acid portion have been described in numerous publications (Howe et al., FEBS J. 2006, 273(22):5101-12; Abdel-Mawgoud et al., Appl Microbiol Biotechnol, 86, 2010, pp. 1323-1336).

[0037] Miao et al., Journal of Surfactants and Detergents, 17(6), 2014, pp. 1069-1080, describes the synthesis of diramnolipid ethyl esters by esterification using ethanol and the suitability of esters as nonionic surfactants.

[0038] International Publication No. 2001 / 010447 and European Patent No. 1 889623 disclose the pharmaceutical and cosmetic uses of rhamnolipids and short-chain rhamnolipid esters (C1-C6; methyl to hexyl esters, linear or branched) particularly in wound healing.

[0039] Rhamnolipids are preferably of general formula (I):

[0040] [ka]

[0041] (In the formula, m is 2, 1 or 0, in particular 1 or 0, n is either 1 or 0, especially 1. R 6 and R 7 These are, independently, identical or different organic radicals having 2 to 24, preferably 5 to 13 carbon atoms, particularly branched, optionally substituted, particularly hydroxysubstituted, optionally unsaturated, particularly optionally monounsaturated, diunsaturated, or triunsaturated alkyl radicals, preferably pentenyl, heptenyl, nonenyl, undecenyl, and tridecenyl, and (CH2) x -CH3 (where x = 1 to 23, preferably 4 to 12) is selected from this group. It is a compound or a salt thereof.

[0042] A mixed composition of rhamnolipids containing more than 90% diramnolipids is preferred.

[0043] -51% to 95% by weight of diramnolipid-C10C10, -0.5% to 9% by weight of monorhamnolipid-C10C10, Includes, The weight percentage is the value relative to the total of all rhamnolipids present. A preferred ramnolipid mixture composition is one in which the weight ratio of dirhamnolipid to monorhamnolipid is greater than 91:9, preferably greater than 97:3, and more preferably greater than 98:2.

[0044] Regarding the use according to the present invention, it is preferable to use a ramnolipid mixture containing 0.5% to 15% by weight of dirhamnolipid-C10C12:1, which is a value relative to the total of all ramnolipids present by weight%.

[0045] Sophorolipids are preferably of the formula (II) or formula (IIa):

[0046]

Chemical formula

[0047] (In the formula, R 1 and R 2 are each independently either H or an acetyl group, R 3 is H, a methyl group, an ethyl group, or a hexyl group, R [[ID=3I]] 4 is independently a saturated or unsaturated divalent branched or unbranched organic group, R 5 is H or a methyl group, provided that the total number of carbon atoms of the groups R 4 and R 5 does not exceed 29.) is a compound of.

[0048] Ramnolipids are available from Stepan Company (Northfield, Illinois, USA) under the name Natsurfact and from Evonik Operations GmbH under the name RHEANCE® One.

[0049] Sophorolipids are available from Holiferm Limited (Manchester, UK) under the name HoneySurf and from Evonik Operations GmbH under the name REWOFERM® SLONE.

[0050] It is preferable to use rhamnolipids and / or sophorolipids in an amount of 0.01% to 10.0% by weight, more preferably 0.1% to 5.0% by weight, relative to the entire coating composition.

[0051] To promote wetting of powdered components in the coating composition, it is preferable to use rhamnolipids and sophorolipids of general formulas (I), (II), and (IIa).

[0052] To optimize the process regime in the production of pigment concentrates, color pastes, pigment pastes, or mill-based coating compositions, it is preferable to use rhamnolipids and sophorolipids of general formulas (I), (II), and (IIa).

[0053] The present invention will be described in detail below with reference to examples. [Brief explanation of the drawing]

[0054] [Figure 1] Figure 1 shows the color locus of the coordinate system. [Figure 2] Figure 2 is a photograph of a 100 mL wide-neck glass bottle after 2 minutes in a pigment wetting properties test. [Examples]

[0055] method Rob-out (scrape-off) test (ΔE) and visual evaluation For the rob-out test, the coating composition was applied to the test base or test substrate using a 150 μm applicator from Leneta. After drying for 5 minutes, the rob-out test was performed by mixing the applied coating with a grinding object (e.g., a gloved finger) with moderate contact pressure using a circular motion. The coating did not completely peel off the substrate, nor did the coating film crack.

[0056] After drying the coating film at room temperature for 7 days, the color values ​​were measured in the area where the lob-out test was performed and in an adjacent area where the lob-out test was not performed. These two values ​​were used to calculate ΔE (delta E). The difference in this color loci represents a measure of the quality of pigment stabilization.

[0057] Lightness and ΔE values ​​were measured using an X-Rite model SP62 spectrometer. As is well known, the L*a*b* color space represents all perceptible colors. It uses a three-dimensional color space in which the luminance value L* is perpendicular to the color plane (a*, b*). The color model is standardized in EN ISO 11664-4 "Colorimetry -- Part 4: CIE 1976 L*a*b* Colour space". Typically, the measuring instrument measures L*, a*, and b* values. These values ​​are color loci in the coordinate system, where L* represents luminance (0=black, 100=white), a* represents the red / green value (-green / +red), and b* represents the blue / yellow value (-blue / +yellow). (See Figure 1)

[0058] Visual evaluation of spots and hue differences in the friction region compared to the unfriction region of the dried film was performed in a colorimetric cabin equipped with D65 daylight illumination, using the following evaluation scale. 0 = Uniform, no spots, no color difference 1 = Has very slight spots, has very slight hue differences 2 = Has slight spots, slight hue differences 3 = Has significant spots, has significant hue differences 4 = There are very significant spots, there are very significant hue differences.

[0059] Experimental example 1. Preparation of pigment concentrates Pigment concentrates were first prepared according to the figures in Tables 1.2 to 1.4. To produce these pigment concentrates, the liquid components were first weighed, and then the pigments were added. After adding the pulverized material (glass beads with a diameter of 2-3 mm, the same volume as the pigment concentrate), the mixture was dispersed in an air-cooled agitator (Lau GmbH FAS 500) for 1 hour (inorganic pigments) or 2 hours (organic pigments and carbon black). The pulverized material was sieved. The resulting filtrate was the pigment concentrate. The comparative example was prepared in the same manner as Tego® Dispers755.

[0060] [Table 1.1]

[0061] [Table 1.2]

[0062] [Table 1.3]

[0063] [Table 1.4]

[0064] 2. Measurement of ΔE value For performance testing, each pigment concentrate from Example 1 was converted into an aqueous coating composition: Pigment concentrate (0.73g) and Kluthe ContiPur Satin brand polyurethane paint (19.27g) were weighed into a 50mL cosmetic pot and homogenized for 1 minute at 2,000rpm using a DAC 150 FVZ speed mixer (Hauschild). Subsequently, a lob-out trial was conducted on all participants. The following results were obtained.

[0065] [Table 2]

[0066] Because the ΔE value is low, the dried coating obtained by using the present invention has far fewer mottled areas than the comparative example. This leads to the conclusion that the dried coating has a uniform (color) appearance.

[0067] [Table 2a]

[0068] Visual evaluation shows that the dried coating obtained using the present invention has a much smaller hue difference and significantly fewer spots than the comparative example.

[0069] 3. Testing the wetting properties of pigments The wetting properties of the pigments were tested by introducing 50g of desalinated water into a 100mL wide-neck glass bottle. Next, appropriate amounts of rhamnolipid and phospholipid were added according to Table 3.1, and the mixture was homogenized by inverting the bottle for 30 seconds to obtain a lipid-water mixture. Subsequently, the pigment Heliogen Blue L7101F (0.1g) was applied to the surface of the lipid-water mixture, and the wetting and settling behavior of the pigment was observed. For the comparative example (CWetting), a commercially available TEGO Dispers 755W was used. The following results were obtained.

[0070] [Table 3.1]

[0071] It was found that the pigment could be wetted more quickly using the present invention. In the comparative example, the wetting operation took more than 60 minutes.

[0072] Figure 2 is a photograph of a 100 mL wide-neck glass bottle after 2 minutes. It is clear that the pigment is on the surface of the TEGO Dispers / water mixture (CWetting). In contrast, in the example, the pigment is wetted and dispersed in the lipid-water mixture.

Claims

1. To improve the wetting rate of powdered components in the coating composition, This reduces dust interference when incorporating the aforementioned powdered components, As a result, the manufacturing of the coating composition enhances labor safety and provides an improved, more uniform color appearance of the dried coating film with respect to ΔE and the hue difference confirmed by visual evaluation. Use of rhamnolipids and / or sophorolipids in the coating composition.

2. The use according to claim 1, characterized in that the coating composition is a paint and coating material selected from interior wall paints, exterior paints, architectural paints, floor coatings, woodworking paints, industrial paints, OEM or refinishing paints for automobiles, primers, primer surfacers, base coats, and top coats.

3. The use according to claim 1, characterized in that it is carried out using a pigment concentrate, color paste, pigment paste, or mill base.

4. The use according to claim 1, characterized in that the coating composition comprises a solid selected from fillers, pigments, dyes, fluorescent whitening agents, ceramic materials, and magnetic materials.

5. The use according to claim 1, characterized in that the coating composition comprises a further additive, the additive being selected from a wetting agent, a dispersion additive, a rheological additive, a leveling aid, or an antifoaming agent.

6. The aforementioned rhamnolipid is general formula (I): 【Chemistry 1】 (In the formula, m is 2, 1 or 0, n is either 1 or 0, R ６ and R ７ These are, independently, identical or distinct organic radicals having 2 to 24 carbon atoms. The use according to claim 1, characterized in that it is a compound or a salt thereof.

7. The use according to claim 1, characterized in that the rhamnolipid is a mixed composition containing more than 90% dirhamnolipid.

8. The rhamnolipid is a mixed composition containing rhamnolipids, The mixed composition 51% to 95% by weight of diramnolipid-C10C10, 0.5% to 9% by weight of monorhamnolipid-C10C10, Includes, The aforementioned weight percentage is the value relative to the total of all rhamnolipids present. The weight ratio of the diramnolipid to the monorhamnolipid is greater than 91:

9. The use according to claim 1, characterized by the above.

9. The rhamnolipid is a mixed composition containing rhamnolipids, The mixed composition comprises 0.5% to 15% by weight of diramnolipid-C10C12:1, The aforementioned weight percent is the value relative to the total sum of all rhamnolipids present. The use according to claim 1, characterized by the above.

10. The sophorolipid is of formula (II) or formula (IIa): 【Chemistry 2】 (In the formula, R １ and R ２ This is independently either an H or an acetyl group. R ３ is H, a methyl group, an ethyl group, or a hexyl group. R ４ These are independently saturated or unsaturated divalent branched or unbranched organic groups. R ５ is either H or a methyl group, However, the group R ４ and R ５ do not exceed 29 in total number of carbon atoms.) The use according to claim 1, characterized in that it is a compound.

11. The use according to claim 1, characterized in that the rhamnolipid and / or the sophorolipid is used in an amount of 0.01% to 10.0% by weight relative to the entire coating composition.

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