Use of rhamnolipid and / or sophorolipid in a coating composition

Abstract

The present invention relates to the use of rhamnolipids and / or sophorolipids in coating compositions for improving the wetting rate of powdery formulation components in such compositions, which results in a reduction of dust nuisance during the addition of the powdery formulation components and thus in an increase in occupational safety during the production of the coating compositions, and in obtaining an improved uniform color appearance of the dry paint film with respect to color tone differences, which are determined by ΔE and visual evaluation.

Description

[0001] The present invention relates to the use of rhamnolipids and / or sophorolipids in coating compositions for obtaining a uniform color appearance of the dry coating film and / or for increasing occupational safety in the production of coating compositions.

[0002] Coatings are applied to surfaces for decorative and / or protective purposes. Formulations for many coating tasks contain particles such as pigments and / or fillers.

[0003] Pigments are coloring substances present in the coating medium in an insoluble, dispersed form. The coating medium is, for example, paint, coating, pigment preparation, printing ink or other organic solvents and other formulations to which pigments are added. Typically, the crude pigments formed in synthesis are used in a ground or pulverized form; for example, the so-called dry grinding and wet grinding methods are used. However, particles with a small diameter have a particularly high tendency to aggregate and must therefore be stabilized.

[0004] The stabilization of pigments is of great importance in the paint industry because pigments, as important formulation components, determine the visual appearance and physicochemical properties of the paint. In order for them to exhibit their best possible effects during coating, they must be evenly and finely distributed in the varnish during the dispersion process. The distribution must be stabilized in order to maintain this state during production, storage, processing and subsequent film formation. Recombination of primary particles and aggregates can lead to, for example, insufficient color depth, floating of the pigments and / or poor tone reproducibility.

[0005] Commercially available paint formulations are only monochromatic in certain cases; frequently, mixtures of two or more different pigments are involved. Also in such systems, all pigments should be wetted sufficiently and be anti-flocculating and evenly distributed throughout the paint film as much as possible. However, if this mixture is disrupted due to pigment separation, this results in a change in the tone of the paint. This defect is called "floating".

[0006] One of the reasons for pigment separation is the flow phenomenon in the dry paint film. During the drying of the paint film, the solvent must be transported from the lower paint layer to its surface; during evaporation, the density of the remaining substances increases, leading to sedimentation. In addition, during evaporation, a cooling effect occurs and the surface tension changes. All of these lead to the formation of eddies, which can manifest in the form of more or less uniform hexagonal units (called Bénard cells). The paint rises upward in the center of the unit and is then distributed over the entire surface and flows back downward at the cell boundaries. These unit flows have long been known - not only in paint. In a colored system, the pigments also participate in these eddies, and assuming that the mobilities of different pigments are similar, they are also transported in a very similar way in the eddies and do not separate. But if there are significant differences in the mobility of the pigments, then their transport characteristics are also different and separation may occur.

[0007] For example, this effect results in a spotty appearance of the dry paint film.

[0008] The rub-out test, which involves determining the hue difference (ΔE) between the rubbed and unrubbed surfaces, is the standard method for testing these blooming effects or other flocculation effects; this is described, for example, in Groteklaes M, Rub-out-Effekt, RD-18-01991(2005)in F., Dill B., Eisenbrand G., Faupel F., Fugmann B., Gamse T., Matissek R., Pohnert G., Rühling A., Schmidt S., Sprenger G., [Online], Stuttgart, Georg Thieme Verlag, [November 2021] https: / / roempp.thieme.de / lexicon / RD-18-01991 This is described in. These effects have an adverse impact on the uniform color appearance of the dry paint film. In addition, these unwanted effects in the dry paint film are often visually evaluated under standard lighting conditions.

[0009] In the context of the present invention, coating medium, coating system, coating composition, paint formulation, and paint medium are used as synonyms.

[0010] The prior art discloses, for example, polymeric wetting agents and dispersants which firstly contain groups having an affinity for pigments, such as carboxyl, amino or phenyl functional groups, and secondly contain side chains which are soluble in the medium. The groups having an affinity for pigments desirably have a rapid orientation on the surface of the pigment and have high performance thereon. The side chains ensure compatibility with the dispersion medium or paint medium and the steric stabilization of the dispersed phase.

[0011] Some publications also mention biosurfactants as dispersants, defoamers, wetting agents or emulsifiers in paints and coatings. Known representatives of these biosurfactants are rhamnolipids and sophorolipids. These lipids are now produced using wild-type isolates of various yeasts, especially Candida bombicola.

[0012] EP 3 006 505 describes, for example, a coating composition which comprises a dispersion consisting of a binder, a biocide and a biosurfactant, the biosurfactant consisting of rhamnolipids and sophorolipids. EP 2 847 285 discloses a similar composition in which an isothiazolone biocide is specifically added. Both documents disclose the synergistic biocidal action of rhamnolipids and sophorolipids with biocides.

[0013] When finely ground particles are added to a coating medium, there may be dust contamination in the production hall. In this operating step, it is well known that an employee, for example, opens a bag containing the particles and pours its contents into an open container which already contains the coating medium. In large production plants, the particles stored in a silo are added to the coating medium. Subsequently, its stirring operation is started. It is also known that the stirring operation can be carried out during the addition of the particles. As long as the pigment is in powder form on the surface of the liquid coating medium, a large amount of dust will be raised. The fine particles can penetrate into the fine alveoli of the lungs, where they can cause diseases. Many companies have therefore installed dust extraction hood devices to minimize the employees' exposure to dust. In addition, employees often have to wear breathing masks, which means that a large amount of heat accumulates under the breathing equipment.

[0014] Therefore, ideally, substances are determined which reduce dust contamination in the production of coating compositions. Ideally, substances are used in coating compositions to obtain a uniform colour appearance of the dry coating film without impairing other properties, such as hue or colour locus.

[0015] It has now surprisingly been found that the use of rhamnolipids and / or sophorolipids in coating compositions is suitable for improving the wetting rate of powdery formulation components in such compositions, which results in a reduction of the dust nuisance during the addition of the powdery formulation components and thus in an increase in occupational safety in the production of coating compositions, as well as in ensuring or improving the retention of a uniform colour appearance of the dry coating film.

[0016] It has also been found that, as described below, compared to conventional coatings without rhamnolipids and / or sophorolipids, the dry coatings have an improved uniform color appearance in terms of color difference, which is determined by ΔE and visual evaluation.

[0017] A further advantage is the reduction in the time taken to introduce the particles into the coating medium, which means an optimization of the process duration.

[0018] The terms powder formulation ingredients, solids, pigments, and particles are used synonymously.

[0019] The coating composition is preferably a preparation for various coating fields, which is applied to the substrate to be coated by coating methods such as spraying, dip coating, roll coating, or brush coating and various printing methods.

[0020] Examples of the coatings in the present invention are paints, coatings, printing inks, and other coatings such as solvent-based or water-based coatings and solventless coatings, powder coatings, UV-curable coatings, low-solids, medium-solids, and high-solids, automotive coatings, wood coatings, baking coatings, two-component coatings, metal coatings, toner compositions. More examples of coatings are given in "Bodo Müller, Ulrich Poth, Lackformulierung und Lackrezeptur, Lehrbuch für Ausbildung und Praxis [Coating Formulations and Coating Combinations, Textbook for Training and Practice], Vincentz Verlag, Hanover (2003), 73 - 1996" and "P.G. Garrat, [Radiation Curing], Vincent Verlag, Hanover (1996)".

[0021] Paints and coatings are interior wall paints, exterior wall paints, architectural paints, floor coatings, wood paints, industrial paints, automotive OEM (Original Equipment Manufacturer) or refinish paints, primers, primer-surfacers, basecoats, and topcoats.

[0022] Examples of printing inks and / or printing varnishes in the present invention are solvent-based or water-based printing inks, flexographic printing inks, gravure printing inks, letterpress or relief printing inks, offset printing inks, lithographic printing inks, printing inks for packaging printing, screen printing inks, printing inks such as those for inkjet printers, inkjet inks, and printing varnishes such as overprint varnishes. More printing ink and / or printing varnish formulations are given in "E.W. Flick, Printing Ink and Overprint Varnish Formulations–Recent Developments, Noyes Publications, Park Ridge NJ, (1990)" and subsequent editions.

[0023] The coating composition preferably comprises solids selected from fillers, pigments, dyes, optical brighteners, ceramic materials, and magnetic materials.

[0024] Examples of pigments are those selected from inorganic pigments such as carbon black; titanium dioxide; zinc oxide; Prussian blue; iron oxides; sulfides of cadmium; chromium pigments such as chromates; molybdates; and mixed chromates and sulfates of lead, zinc, barium, and calcium and mixtures thereof. More examples of inorganic pigments are described in the book "H. Endriss, Aktuelle anorganische Bunt-Pigmente [Current Inorganic Colored Pigments], Vincentz Verlag, Hannover (1997)".

[0025] Examples of organic pigments are those selected from azo, diazo, condensed azo, naphthol, metal complex, thioindigo, indanthrone, isoindanthrone, anthanthrone, anthraquinone, isodibenzanthrone, triphenyl dioxazine, quinacridone, perylene, diketopyrrolopyrrole, and phthalocyanine dyes. More examples of organic pigments are described in the book "W. Herbst, K. Hunger, Industrial Organic Pigments, VCH, Weinheim (1993)".

[0026] Examples of fillers are selected from talc, kaolin, silicas, barite, and lime; ceramic materials such as aluminum oxide, silicate, zirconium oxide, titanium oxide, boron nitride, silicon nitride, boron carbide, mixed silicon aluminum nitride, and metal titanates; magnetic materials such as magnetic oxides of transition metals such as iron oxides, cobalt-doped iron oxides, and ferrites; and metals such as iron, nickel, cobalt, and their alloys.

[0027] Those skilled in the art will realize that such coating compositions may include other ingredients. As the liquid medium, they may contain organic solvents (such as acetates like butyl acetate or ethyl acetate, hydrocarbons like petroleum spirits of various boiling ranges, alcohols, ethers, diols and diol ethers) and / or water, as known in the prior art, depending on the binder used.

[0028] Conventional binders can be used. Alkyd resins, acrylates, styrene-acrylates, epoxy resins, polyvinyl acetates, polyesters or polyurethane binders can be preferably used. Any kind of curing is possible, for example by oxidative drying, physical drying, self-crosslinking, UV or electron beam curing or by baking crosslinking.

[0029] It is conceivable that the coating composition contains additional additives, such as preferably wetting agents, dispersion additives, rheological additives, leveling aids or defoamers.

[0030] Those skilled in the art realize that the production of a coating composition containing particles can be achieved, for example, by using pigment concentrates, color pastes, pigment slurries or liquid formulations of particles. However, it is also possible to produce millbases for use in the production of coating compositions in a timely manner.

[0031] The present invention thus preferably also provides the use of rhamnolipids and / or sophorolipids in pigment concentrates, color pastes, pigment slurries or liquid formulations of particles or millbases.

[0032] Rhamnolipids and sophorolipids are surfactants that can be prepared by fermentation.

[0033] Rhamnolipids are composed of one to two rhamnose units and one to three mainly β-hydroxy fatty acids. The fatty acids can be saturated or unsaturated.

[0034] Variations in the chain length and number (homologues) of the fatty acid moiety have been described in many publications (Howe et al., FEBS J. 2006; 273(22): 5101-12; Abdel-Mawgoud et al., Appl Microbiol Biotechnol, 86, 2010; p. 1323-1336).

[0035] Miao et al., Journal of Surfactants and Detergents, 17(6), 2014; 1069-1080, described the synthesis of di-rhamnolipid ethyl esters by esterification with ethanol and the suitability of said esters as non-ionic surfactants.

[0036] WO 2001010447 and EP1889623 disclose the pharmaceutical and cosmetic applications of rhamnolipids and short-chain rhamnolipids (C1-C6; methyl to hexyl esters, linear or branched), especially their applications in wound healing.

[0037] The rhamnolipid is preferably a compound of general formula (I) or a salt thereof

[0038]

[0039] wherein

[0040] m = 2, 1 or 0, especially 1 or 0,

[0041] n = 1 or 0, especially 1,

[0042] R 6 and R 7 = independently identical or different organic groups having 2 to 24, preferably 5 to 13 carbon atoms, which are especially optionally branched, optionally substituted, especially hydroxy-substituted, optionally unsaturated, especially optionally mono-unsaturated, di-unsaturated or tri-unsaturated alkyl groups, preferably selected from pentenyl, heptenyl, nonenyl, undecenyl and tridecenyl and (CH2) x -CH3, where x = 1 to 23, preferably 4 to 12.

[0043] Preferably, the mixed composition of rhamnolipids contains >90% of di-RL.

[0044] Preferably, the mixed composition of rhamnolipids contains:

[0045] 51% to 95% by weight of di-RL-C10C10, and

[0046] 0.5% to 9% by weight of mono-RL-C10C10, where the weight percentages are based on the total of all rhamnolipids present, provided that the weight ratio of dirhamnolipid to monorhamnolipid is greater than 91:9, preferably greater than 97:3, more preferably greater than 98:2.

[0047] For the uses according to the invention, a rhamnolipid mixture containing 0.5% to 15% by weight of di-RL-C10C12:1 is preferably used, where the weight percentages are based on the total of all rhamnolipids present.

[0048] The sophorolipid is preferably a compound of formula (II) or (IIa)

[0049]

[0050] wherein

[0051] R 1and R 2 is independently H or acetyl,

[0052] R 3 is H, methyl, ethyl or hexyl,

[0053] R 4 is independently a saturated or unsaturated divalent branched or unbranched organic group,

[0054] R 5 is H or methyl,

[0055] provided that the total number of carbon atoms in the groups R 4 and R 5 does not exceed 29.

[0056] Rhamnolipids can be obtained from Stepan (Northfield, IL, USA) under the name Natsurfact and from Evonik Operations GmbH under One.

[0057] Sophorolipids can be obtained from Holiferm Limited (Manchester, UK) under the name HoneySurf and from Evonik Operations GmbH under SL ONE.

[0058] Based on the total coating composition, it is preferred to use 0.01 wt% to 10.0 wt%, more preferably 0.1 wt% to 5.0 wt% of rhamnolipids and / or sophorolipids.

[0059] It is preferred to use rhamnolipids and sophorolipids of general formulas (I), (II) and (IIa) to accelerate the wetting of the powdery formulation components in the coating composition.

[0060] It is preferred to use rhamnolipids and sophorolipids of general formulas (I), (II) and (IIa) to optimize the process regime of the coating composition for producing pigment concentrates, color pastes, pigment slurries or abrasives.

[0061] The present invention will be described in detail below by working examples.

[0062] Method

[0063] Wipe-off test (ΔE) and visual evaluation

[0064] For the rub-out test, the coating composition is applied to a test substrate or test base material using a 150 μm applicator from Leneta. After a drying time of 5 minutes, the rub-out test is carried out, which consists of mixing the applied paint with a grinding body, such as a gloved finger, in a circular motion with a moderate contact pressure. There should be no complete pushing off of the coating from the substrate or tearing of the paint film.

[0065] After the paint film has been dried at room temperature for seven days, the color values are determined in the area where the rub-out test was completed and in an adjacent area that was not subjected to the rub-out test. These two values are used to calculate ΔE (delta E). This difference in color loci is an indicator of the quality of pigment stabilization.

[0066] The color values and ΔE values are determined using an X-Rite Model SP 62 spectrophotometer. It is well known that the L*a*b* color loci describe all perceptible colors. It uses a three-dimensional color locus, where the lightness value L* is perpendicular to the color plane (a*, b*). This color model is standardized in EN ISO 11664-4 “Colorimetry--Part 4:CIE 1976 L*a*b* Colourspace”. Usually, the measuring instrument measures the L*, a*, and b* values. These values then produce color loci in a coordinate system, where L* represents lightness (0 = black; 100 = white), a* represents the red / green value (- green / + red), and b* represents the blue / yellow value (- blue / + yellow). (See Figure 1 )

[0067] Using the following evaluation grades, in a color inspection room with D65 daylight illumination, a visual evaluation of the dry film is carried out for the spottiness and hue difference between the rubbed area and the unrubbed area:

[0068] 0 = Uniform, no spots, no color difference

[0069] 1 = Very slight spots, very slight hue difference

[0070] 2 = Slight spots, slight hue difference

[0071] 3 = Significant spots, significant hue difference

[0072] 4 = Very significant spots, very significant hue difference Description of the Drawings

[0073] Figure 1 Shows the L*a*b* color loci.

[0074] Figure 2 Shows a photograph of a 100 ml wide-neck glass bottle after 2 minutes. Example

[0075] 1. Preparation of Pigment Concentrates

[0076] First, prepare the pigment concentrates according to the information in Tables 1.2 - 1.4. To prepare these pigment concentrates, first weigh the liquid components and then add the pigments. After adding the grinding media (glass beads with a diameter of 2 to 3 mm, having the same volume as the pigment concentrate), disperse in a stirrer with air cooling (FAS 500, from Lau GmbH) for 1 hour (inorganic pigments) or 2 hours (organic pigments and carbon black). Screen out the grinding media. The resulting filtrate is the pigment concentrate.

[0077] Similarly use Dispers 755 to prepare the comparative examples.

[0078] Table 1.1: Materials Used

[0079]

[0080]

[0081] Table 1.2: Pigment Concentrates Containing Bayferrox 130M

[0082]

[0083] Table 1.3: Pigment Concentrates Containing Heliogen Blue L7101F

[0084]

[0085] Table 1.4: Pigment Concentrates Containing Special Black 4

[0086]

[0087] 2. Determination of ΔE Value

[0088] For the performance test, convert each pigment concentrate from Example 1 into an aqueous coating composition:

[0089] Weigh 0.73 g of the pigment concentrate and 19.27 g of a polyurethane - based paint of the ContiPur Satin brand from Kluthe in a 50 - ml cosmetic jar and homogenize at 2000 rpm for 1 minute using a Speed Mixer DAC 150FVZ (from Hauschild).

[0090] Thereafter, in each case, a wipe - off test was carried out. The following results were obtained:

[0091] Table 2:

[0092] L* a* b* Wipe off ΔE CBay 66.58 19.30 6.60 1.08 Bay1 67.58 18.73 6.04 0.61 Bay2 67.48 18.04 4.57 0.85 C Blue 65.14 -21.95 -34.39 1.07 Blue 1 68.09 -21.67 -31.85 1.04 Blue 2 65.73 -21.77 -34.07 0.58 C Black 49.05 -0.80 -3.35 1.01 Black 1 49.19 -0.83 -3.63 0.74 Black 2 49.59 -0.81 -3.67 0.68

[0093] Based on the low ΔE value, compared with the comparative example, the dry paint film obtained by the use according to the present invention has a less significant blooming effect. It can be concluded that the dry paint film has a uniform (color) appearance.

[0094] Table 2a: Visual evaluation

[0095] Visual assessment CBay 4 Bay1 2 Bay2 3 C Blue 4 Blue 1 3 Blue 2 2 C Black 4 Black 1 2 Black 2 2

[0096] This visual evaluation shows that, compared with the comparative example, the dry paint film obtained by the use according to the present invention has a smaller hue difference and significantly lower speckle degree.

[0097] 3. Test of pigment wetting characteristics

[0098] The wetting characteristics of the pigment were tested by introducing 50 g of softened water into a 100 ml wide-necked glass bottle in each case. Then, an appropriate amount of rhamnolipid and phospholipid was added according to Table 3.1, and the mixture was homogenized by inverting the bottle for 30 seconds to obtain a lipid-water mixture. Then, 0.1 g of the pigment Heliogen Blue L7101F was coated onto the surface of the lipid-water mixture, and the wetting and sedimentation behavior of the pigment was observed.

[0099] For the comparative example (C wetting), commercially available TEGO Dispers 755W was used.

[0100] The following results were obtained:

[0101] Table 3.1 Wetting characteristics of pigments

[0102]

[0103] It was found that due to the use according to the present invention, the pigment can be wetted faster. In the comparative example, the wetting operation took more than 60 minutes.

[0104] Figure 2 A photograph of a 100 ml wide-necked glass bottle after 2 minutes is shown. Obviously, the pigment is located on the surface of the TEGO Dispers / water mixture (C wetting). However, in the examples of the present invention, the pigment is wetted and distributed in the lipid-water mixture.

Claims

1. Use of rhamnolipid and / or sophorolipid for improving the wetting rate of powdery formulation components in a coating composition, which results in a reduction of dust hazards during the addition of powdery formulation components, and thus leads to an increase in occupational safety during the production of the coating composition, and leads to obtaining an improved uniform color appearance of the dry paint film in terms of color difference, the color difference being determined by ΔE and visual evaluation.

2. The use according to claim 1, characterized in that The coating composition is a paint and coating selected from the following: architectural paint, industrial paint.

3. The use according to claim 1, wherein The coating composition is a paint and coating selected from the following: interior wall paint, exterior wall paint, floor coating, wood paint.

4. The use according to claim 1, characterized in that The coating composition is automotive OEM or refinish paint.

5. The use according to claim 1, wherein The coating composition is a substrate.

6. The use according to claim 1, wherein The coating composition is a surfacer.

7. The use according to claim 1, characterized in that The coating composition is a primer or topcoat.

8. The use according to claim 1, wherein The use occurs in a pigment concentrate.

9. The use according to claim 1, wherein The use occurs in a color paste.

10. The use according to claim 1, wherein The use occurs in a pigment paste.

11. The use according to claim 1, wherein The use occurs in an abrasive.

12. The use according to any one of claims 1-11, characterized in that The coating composition contains solids selected from fillers, pigments.

13. The use according to any one of claims 1-11, characterized in that The coating composition contains solids of dyes.

14. The use according to any one of claims 1 to 11, characterized in that The coating composition contains solids of fluorescent whitening agents.

15. The use according to any one of claims 1-11, characterized in that The coating composition contains solids of ceramic materials.

16. The use according to any one of claims 1 to 11, characterized in that The coating composition contains solids of magnetic materials.

17. The use according to any one of claims 1 to 11, characterized in that The coating composition contains additional additives.

18. The use according to claim 17, wherein The additional additives are wetting agents, dispersion additives, rheological additives, leveling aids or defoamers.

19. The use according to any one of claims 1-11, characterized in that The rhamnolipid is a compound of general formula (I) or a salt thereof wherein m = 2, 1 or 0, n = 1 or 0, R 6 and R 7 = independently identical or different organic groups having 2 to 24 carbon atoms.

20. The use according to claim 19, characterized in that R 6 and R 7 = independently identical or different organic groups having 5 to 13 carbon atoms.

21. The use according to claim 19, characterized in that R 6 and R 7 is a branched or unbranched, substituted or unsubstituted, saturated or unsaturated alkyl group.

22. The use according to claim 21, wherein R 6 and R 7 is hydroxy-substituted.

23. The use according to claim 21, characterized in that R 6 and R 7 is a mono-unsaturated, di-unsaturated or tri-unsaturated alkyl group.

24. The use according to claim 19, characterized in that R 6 and R 7 selected from pentenyl, heptenyl, nonenyl, undecenyl, tridecenyl and (CH2) x -CH3, where x = 1 to 23.

25. The use according to claim 24, characterized in that x = 4 to 12.

26. The use according to any one of claims 1-11, characterized in that The rhamnolipid is a mixed composition having > 90% of di-RL.

27. The use according to any one of claims 1 to 11, characterized in that The rhamnolipid is a mixed composition containing rhamnolipid, characterized in that the mixed composition contains 51% to 95% by weight of di-RL-C10C10, and 0.5% to 9% by weight of mono-RL-C10C10, where the weight percentages are based on the total sum of all rhamnolipids present, provided that the weight ratio of dirhamnolipid to monorhamnolipid is greater than 91:

9.

28. The use according to claim 27, wherein The weight ratio of dirhamnolipid to monorhamnolipid is greater than 97:

3.

29. The use according to claim 27, characterized in that The weight ratio of dirhamnolipid to monorhamnolipid is greater than 98:

2.

30. The use according to any one of claims 1 to 11, characterized in that The rhamnolipid is a mixed composition containing rhamnolipid, characterized in that the mixed composition contains 0.5% to 15% by weight of di-RL-C10C12:1, where the weight percentage is based on the total sum of all rhamnolipids present.

31. The use according to any one of claims 1-11, characterized in that The sophorolipid is a compound of formula (II) or (IIa) wherein R 1 and R 2 are independently H or acetyl, R 3 is H, methyl, ethyl or hexyl, R 4 is independently a saturated or unsaturated divalent branched or unbranched organic group, R 5 is H or methyl, Provided that the total number of carbon atoms in the R 4 and R 5 groups does not exceed 29.

32. The use according to any one of claims 1-11, characterized in that Based on the total coating composition, the dosage of the rhamnolipid and / or sophorolipid is in the range of 0.01% to 10.0% by weight.

33. The use according to claim 32, wherein Based on the total coating composition, the dosage of the rhamnolipid and / or sophorolipid is in the range of 0.1% to 5.0% by weight.

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