METHOD FOR MODIFYING THE COLOR-HUE OF COLORED SYNTHETIC YARNS AND FILAMENTS, AND SYSTEM FOR CARRYING IT OUT

Abstract

The invention provides a method for modifying the color hue of already colored synthetic yarns and/or filaments in a conventional melt-spinning process, which allows correcting deviations from tolerances in the color hue by the manufacturers themselves. The method comprises storing color coordinates of a target hue; measuring color coordinates of colored yarns and filaments to be corrected; comparing the data to provide deviations beyond tolerances; preparing a correcting-liquid-masterbatch composition; converting the deviations beyond tolerances into a dose of the correcting liquid-masterbatch composition; and adding such dose to molten mass of the synthetic yarns and filaments.

The invention is also directed to a system suitable for performing the method of color hue modification and/or correction.

Claims

1-15. (canceled)

16. A method for modifying color hue of colored synthetic yarns and/or filaments to a target color hue during a conventional melt-spinning process, characterized in that the method comprises the following steps: storing color coordinates a.sub.t* and/or b.sub.t* of the target color-hue including limits of tolerances; taking measurements of color coordinates a* and/or b* in the colored synthetic yarns and/or filaments to identify the actual color hue; comparing stored target color hue coordinates with the actual color hue coordinates measured, that is Δa and/or Δb, to determine if the differences, if any, are beyond limits of the target color hue tolerances; preparing at least one correcting liquid-masterbatch composition comprising a liquid polymer carrier and at least one colorant dispersed therein, with the proviso that one of the colorants included in the correcting liquid-masterbatch composition is selected to be the same as present in the colored synthetic yarns and/or filaments, wherein the colorant concentration is between 1% and 40% by weight to the weight of the correcting liquid-masterbatch composition; converting the observed differences in the color coordinates, i.e. Δa and/or Δb, into a dose of the prepared correcting-liquid-masterbatch composition; adding such dose of the correcting-liquid-masterbatch composition during the extrusion of the colored synthetic yarns and/or filaments to correct the actual color hue toward the target color hue, thus resulting in a corrected color hue modifying the actual color hue to be within the target color hue tolerances, wherein the dose is equal to or lower than 3% by weight with respect to the weight of the colored synthetic yarns and/or filaments; and optionally verifying the corrected color hue in the corrected and colored synthetic fibers and/or filaments by taking new measurements of color coordinates am* and/or bm* in the newly obtained colored synthetic yarns and/or filaments in order to assure that the corrected color hue is within limits of target color hue tolerances.

17. The method according to claim 16, wherein the differences in the color coordinates, that is Δa and/or Δb, are converted into a dose of the correcting-liquid-masterbatch composition by a relationship that is substantially linear.

18. The method according to claim 16, wherein the preparation of the correcting-liquid-masterbatch composition comprises: preparing a dispersion of at least one colorant in a liquid polymer carrier, with the proviso that at least one of the colorants included in the correcting liquid-masterbatch composition is selected to be the same as present in the colored synthetic yarns and/or filaments whose color-hue is desired to be corrected.

19. The method according to claim 16, wherein the correcting-liquid-masterbatch composition comprises a colorant concentration between 1 and 30% by weight to the weight of the correcting-liquid-masterbatch composition.

20. The method according to claim 19, wherein the correcting-liquid-masterbatch composition comprises a colorant concentration between 5 and 10% by weight to the weight of the correcting-liquid-masterbatch composition.

21. The method according to claim 16, wherein the colorant included in the correcting-liquid-masterbatch composition is selected from an organic pigment, an inorganic pigment or solvent dyes, and it is further selected having the same color index value than one of the colorants that is present in the colored synthetic yarns and/or filaments.

22. The method according to claim 16, wherein the correcting-liquid-masterbatch composition is added in a concentration equal to or lower than 1% by weight with respect to the weight of the colored synthetic yarns and/or filaments.

23. The method of claim 22, wherein the correcting-liquid-masterbatch composition is added between 0.1 and 0.6% by weight with respect to the weight of the colored synthetic yarns and/or filaments.

24. The method according to claim 16, wherein the differences beyond limits of tolerances, that is Δa and/or Δb, are within a value of |3|.

25. The method according to claim 24, wherein the differences beyond limits of tolerances, that is Δa and/or Δb, are within a value of |1|.

26. The method according to claim 16, wherein the synthetic polymer for forming yarns and/or filaments is selected from polyester, co-polyester, polyamide, polyethylene, polypropylene, polyethyleneterephthalate (PET), polybutyleneterephthalate (PBT), polytrimethyleneterephthalate (PTT), polylactic acid (PLA) or a mixture thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0124] FIG. 1 is a graph showing the variation of the color coordinate a* according to Example 1 with respect to a colorant percentage increase of 0.03, 0.06, 0.12 and 0.20% by weight to the weight of a colored yarn. This figure shows the substantially linear relationship between the variation of the color coordinate a* with respect to the dosages of correcting-liquid-masterbatch compositions containing the colorant percentage. See Tables 4 to 7, wherein the correspondence of the colorant percentage to the correcting-liquid masterbatch dosage is included.

[0125] FIG. 2 is a graph showing the variation of the color coordinate b* according to Example 1 with respect to a colorant percentage increase of 0.03, 0.06, 0.12 and 0.20% by weight to the weight of a colored yarn. This figure shows the substantially linear relationship between the variation of the color coordinate b* with respect to the dosages of correcting liquid-masterbatch compositions containing the colorant percentage. See Tables 4 to 7, wherein the correspondence of the colorant percentage to the correcting-liquid masterbatch dosage is included.

[0126] FIG. 3 depicts a schematic view of a fusion spinning system, wherein the extrusion means 1 is configured and adapted to receive, in use, a dose of the correcting liquid-masterbatch composition of a portable equipment 2 during the extrusion of the synthetic yarns and/or filaments in the extruder 10 to which it is coupled. In this embodiment, the portable equipment 2 is positioned at a position proximal to the spinneret plate. However, the portable equipment 2 can be positioned in any other position along the extruder 10.

[0127] FIG. 4.1 depicts a detailed view of an embodiment of the portable equipment 2 of the invention, showing one reservoir as housing means 20 configured and adapted to house therein a correcting-liquid-masterbatch composition. The portable equipment 2 comprises correction-supplying means 21 coupled to the housing means 20 for supplying, in use, a dose of the correcting-composition to the extrusion means 1.

[0128] FIG. 4.2 depicts a detailed view of another embodiment of the portable equipment 2 of the invention, showing three reservoirs as housing means 20, each one independently, configured and adapted to house therein a correcting liquid-masterbatch composition. The portable equipment 2 comprises correction-supplying means 21 coupled to the housing means 20. In this embodiment, the portable equipment 2 further comprises a static mixer as masterbatch-mixing means 22 coupled to the correction supplying means 21 for mixing several dosages of the correcting liquid-masterbatch compositions housed in the reservoirs for supplying, in use, a mixture of dosages to the extrusion means 1.

[0129] FIG. 5 is a processor-operating scheme showing the electronic processor means 4, which are operatively connected to the colorimetric readout means 3 to generate a dose-indicative signal of the correcting liquid-masterbatch composition contained in the portable equipment 2. The electronic processor means 4 are associated to the colorimetric readout means 3 for supplying, in use, a dose thereof to the extrusion means 1.

DETAILED DESCRIPTION OF THE INVENTION

[0130] Hereinafter, the best mode for carrying out the present invention is described in detail making reference to FIG. 3-5.

[0131] A variety of extrusion equipment exists and choosing which to use will depend on the characteristics and properties of the product to be extruded. The preferable equipment is a co-rotating twin-screw extruder, characterized by the fact that its screws rotate in the same direction. This extrusion equipment transfers a large amount of mechanical energy (called shear force) to the material, enabling large amounts of colorants and/or additives to be dispersed. The configuration of the screws is essential in order to guarantee good productivity and optimum product quality. The screws are composed of different assembled elements, which according to their geometry and position, distribute, disperse or transport the material.

[0132] The starting point for melt spinning are the thermoplastic polymers (referred to also as synthetic polymer, main polymer or polymer support) in the form of chips, granulate or pellets, which are added through the polymer supplying apparatus 11 such a feeder or similar to the extruder 10, wherein they are melted forming a viscous fluid mass. The viscous mass is dosed by means of a volumetric pump to a filtration system and a plate with holes called spinneret (FIG. 3). The molten polymer is forced through spinneret holes at high pressure, obtaining a series of filaments that together will form the yarn. The cooling of the viscose mass at the outlet of the spinneret plate is carried out by a controlled flow of air, the filaments are then lubricated with a sizing oil emulsion and are finally wound on a bobbin.

[0133] Usually, the thermoplastic polymer comprises a solid- and/or a liquid-masterbatch dispersed therein, which is added by means of a gravimetric system, or in viscose form by means of lateral extruder, in the extrusion area for forming the fiber with the desired properties. Masterbatch supplying apparatus 12 such a hopper (FIG. 3), or a lateral extruder (not represented) or similar can be coupled to the extruder assembly 1 for such purpose.

[0134] Profile of temperatures in the extruder 10 can be modified according to the dimensions of the extruder 10, the time the molten mass is there or the particularities of the type of the used extrusion equipment, as utilized and determined by the skilled person.

[0135] In this embodiment, the correcting-liquid-masterbatch composition is added by means of the portable equipment 2 in a proximal position to the spinneret (FIG. 3). At this position, the correcting-liquid-masterbatch composition is added under pressure to the extruder 10. Preferably, the correction-supplying apparatus 21 includes a variable frequency drive, and a dosing pump (not shown) configured and adapted to supply under pressure the dose of the correcting liquid-masterbatch composition from the reservoir 20 to the extruder 10 to which it is coupled (FIGS. 4.1 and 4.2).

[0136] FIG. 4.2 shows the portable equipment 2, which further comprises more than one housing apparatus 20 (reservoir), each one independently, configured and adapted to house therein a correcting-liquid-masterbatch composition; the liquid-masterbatch mixing apparatus 22 is configured and adapted to mix several dosages of the correcting-liquid-masterbatch compositions housed in the housing apparatus 20 and to supply, in use, the mixture to the extrusion assembly 1 to which it is coupled. Preferable liquid-masterbatch mixing apparatus 22 is a static mixer.

[0137] The colorimetric readout apparatus 3 is used for taking of a readout of the actual color-hue-coordinates (a*, b*) in the colored synthetic yarns and/or filaments obtained in melt-spinning process.

[0138] These measurements are compared, preferably using computer software programs for speed and reliability, with the stored target-color-hue-coordinates (a.sub.t*, b.sub.t*) in order to determine deviations in the color-hue-coordinates (4a, 4b) beyond limits of target color hue tolerances. These deviations have a linear relationship with the dose of the correcting liquid-masterbatch composition for correcting the color hue deviations and return the actual color hue to the target color hue tolerance value (FIGS. 1 and 2).

[0139] The electronic processor apparatus 4 associated to these deviations by a linear relationship with the dose of the correcting liquid-masterbatch composition, preferably using computer software programs for speed and reliability, generates a dose-indicative signal of the dose, in use, to be supplied to the extrusion assembly 1. The extrusion assembly 1 configured and adapted to receive, in use, the dose of the correcting liquid-masterbatch composition of the portable equipment 2 allows adding the dose for correcting the actual color hue of the colored synthetic yarns and/or filaments to the extruder 10 during the extrusion of the colored synthetic polymer for forming fiber and/or filaments. The resulting corrected color hue of the yarns and/or filaments is within the target color hue tolerances.

[0140] Preferable colorimetric readout apparatus 3 is a spectrophotometer. The spectrophotometer takes measure differences in the yarn's color. The yarn and/or filament can be texturized or not. A preferable spectrophotometer is the Datacolor 650 Spectrophotometer those main features are included below:

TABLE-US-00001 Datacolor 650/600/400 Instrument Specifications ITEM DESCRIPTION Instrument Type Dual beam integrating sphere with xenon flash lamp. Measuring Geometry Diffuse illumination, 8° viewing in conformance with CIE publication No. 15.2 Colorimetry. Illumination Source Pulsed xenon, filtered to approximate D65. Sphere Diameter 152 mm/6.0 inches Specular Port Automated specular included or specular excluded Spectral Analyzer Proprietary SP 2000 analyzer with dual 256-diode array and high- resolution holographic grating. Wavelength Range 360-700 nm Photometric Range 0 to 200% Black Trap High performance Aperture Configuration Large Area View. 30 mm illuminated/26 mm viewed Medium Area View. 20 mm illuminated/16 mm viewed Small Area View. 9 mm illuminated/5 mm viewed Ultra-Small Area View. 6.5 mm illuminated/2.5 mm viewed X-Ultra Small Area View. 3 mm illuminated/2.5 mm viewed Power 85 to 264 VAC, 47 to 63 Hz, 80 VA peak, 35 VA typical Absolute Operating 5° to 40° C, 5% to −85% RH, Environment non-condensing Interface Serial: RS232, 9600/115200 baud (shipped as 19200) USB: 1.1 or higher Dimensions Metric Height 325 mm Width 312 mm Depth 471 mm Weight 14.97 mm  

TABLE-US-00002 Features by Model 650 FEATURE Model 650 Reporting Interval 5 or 10 nm** Effective Bandwidth 5 or 10 nm** 20 Read Repeatability on WhiteTile 0.015 (max)  Using Dual Flash (CIELAB) Inter-instrument Agreement-Reflectance 0.15 (max) Measurements* (CIEL*a*b*) 0.08 (avg)  Transmittance Measurements   Yes*** Inter-instrument Agreement for ±0.20% at 85% T Regular Transmittance (550 nm)* ±0.10% at 32% T Inter-instrument Agreement for  ±.40% at 42% T Diffuse Transmittance (550 nm)* Inter-instrument Agreement for .sup. ±0.15% at 10% TH Transmission Haze Measurements* Lens 4 position auto-zoom Aperture Plates 4 standard LAV SAV USAV MAV barium coated 2 optional MAV XUSAV Aperture Detection Yes Automated, adjustable UV Calibration Yes UV Cutoff Filters 400 nm 420 nm 460 nm Remote Measurement Button Yes Vertical Mount**** No *Measurements made at 23° C +/− 1° C. **Software must be capable of 5 nm reporting ***Capable of measuring regular, total and diffuse transmission ****Includes sample viewer assembly

[0141] Standard Illuminants have been used to determinate the color coordinates.

[0142] The Standard Illuminants to determinate the color coordinates (a*, b*), the target color coordinates (a.sub.t*, b.sub.t*), the modified color coordinates (a.sub.m*, b.sub.m*), or the differences in the color coordinates (4a, 4b) have been the Standard Illuminant D65, the Standard Illuminant A, and Standard Illuminant F11.

[0143] According to the common general knowledge, “Standard Illuminant D65” is defined as the average daylight (including ultraviolet wavelength region) with a correlated color temperature of 6504K; should be used for measuring specimens, which will be illuminated by daylight including ultraviolet radiation.

[0144] According to the common general knowledge, “Standard Illuminant A” is defined as the incandescent light with a correlated color temperature of 2856K; should be used for measuring specimens, which will be illuminated by incandescent lamps.

[0145] According to the common general knowledge, “Standard Illuminant F11” represents a narrow tri-band fluorescent of 4000° Kelvin color temperature, CRI 83. TL84 represents a Philips narrow tri-band fluorescent lamp (4000° Kelvin, similar to CIE illuminant F11) typically found in Marks & Spencer stores in Europe. In practice, CIE F11 and Philips TL84 illuminants are similar. The difference in color values calculated using F11 and TL84 should be very close in absolute values and would agree in differences.

Examples

[0146] Hereinafter, the present invention is disclosed in more detail and specifically with reference to the Examples and Figures, which however are not intended to limit the present invention.

Examples

Example 1: Modification System by Using a Correcting Liquid-Masterbatch Composition in a Fusion Spinning Process with the Method of the Present Invention

[0147] The polymer support was polyester having a solid-masterbatch dispersed therein.

[0148] Spinning a gray polyester yarn was carried out by dosing a solid masterbatch. The solid masterbatch was developed for the mass coloring of threads for the manufacture of fabrics for upholstering car seats. The demands of color in this automotive sector are extremely high and deviations between batches are not tolerated.

[0149] The solid-masterbatch (solid-M) was prepared with the following pigments: PIGMENT BLACK 7, PIGMENT BLUE 29, PIGMENT GREEN 7, PIGMENT WHITE 6, PIGMENT RED 202. The solid-M contained 16.4% by weight of pigment in total. To obtain the final color, the dosage of this solid-M on the total weight of polyester is 2.5%. This implies that “on fiber” the amount of colorant contributed will be 0.41% (16.4×2.5/100).

[0150] The extruded yarn was textured by air. Then, a fabric was knitted from this yarn. This fabric was placed in the sample holder of a Datacolor 650 spectrophotometer. Averaged readings were made in the spectrophotometer to determine the coordinates L*, a* and b*. The results for each of the three illuminants used were the following seen in Table 1:

TABLE-US-00003 TABLE 1 Polyester polymer with 2.5% wt. of the above prepared solid-M Ilum./Obs. L* a* b* D65 10 Deg 32.56 0.35 0.98 A 10 Deg 32.67 0.64 1.11 F11 10 Deg 36.65 0.33 1.16

[0151] As liquid masterbatches (liquid-M) ready for color correction, the compositions shown below in Table 2 were prepared and ready for use.

TABLE-US-00004 TABLE 2 Liquid Masterbatch (L-M) Yellow- Red- Green- Blue- pigment pigment pigment pigment Color index (C.I.) P. Y. 147 P. R. 202 P. G. 7 P. Bl. 15:3 % PIGMENT 50% 35% 38% 44%

[0152] Four different corrections in an incremental way, for each pigment, were performed to demonstrate the correction capacity of the method of the invention.

[0153] The following dosages of liquid-masterbatches (L-M) were added to the colored yarn during extrusion, as seen in Table 3:

TABLE-US-00005 TABLE 3 solid-M contained Assay in the yarn Yellow-L-M Red-L-M Green-L-M Blue-L-M 1 2.5% 0.060% 0.086% 0.079% 0.068% 2 2.5% 0.120% 0.171% 0.158% 0.136% 3 2.5% 0.240% 0.343% 0.316% 0.273% 4 2.5% 0.400% 0.571% 0.526% 0.455%

[0154] The total pigment percentage on the yarn as well as the pigment percentage of the correcting-liquid-M added to correct the color hue, and of the solid-M already contained in the colored yarn are included below for each of the colors, as seen in Tables 4-7:

TABLE-US-00006 TABLE 4 solid-M contained in the yarn Yellow-L-M % total % pigment % pigment pigment on Assay Dosage on the yarn Dosage on the yarn the yarn 1 2.5% 0.41% 0.060% 0.03% 0.44% 2 2.5% 0.41% 0.120% 0.06% 0.47% 3 2.5% 0.41% 0.240% 0.12% 0.53% 4 2.5% 0.41% 0.400% 0.20% 0.61%

TABLE-US-00007 TABLE 5 solid-M contained in the yarn Red-L-M % total % pigment % pigment pigment on Assay Dosage on the yarn Dosage on the yarn the yarn 1 2.5% 0.41% 0.086% 0.03% 0.44% 2 2.5% 0.41% 0.171% 0.06% 0.47% 3 2.5% 0.41% 0.343% 0.12% 0.53% 4 2.5% 0.41% 0.571% 0.20% 0.61%

TABLE-US-00008 TABLE 6 solid-M contained in the yarn Green-L-M % total % pigment % pigment pigment on Assay Dosage on the yarn Dosage on the yarn the yarn 1 2.5% 0.41% 0.079% 0.03% 0.44% 2 2.5% 0.41% 0.158% 0.06% 0.47% 3 2.5% 0.41% 0.316% 0.12% 0.53% 4 2.5% 0.41% 0.526% 0.20% 0.61%

TABLE-US-00009 TABLE 7 solid-M contained in the yarn Blue-L-M % total % pigment % pigment pigment on Assay Dosage on the yarn Dosage on the yarn the yarn 1 2.5% 0.41% 0.068% 0.03% 0.44% 2 2.5% 0.41% 0.136% 0.06% 0.47% 3 2.5% 0.41% 0.273% 0.12% 0.53% 4 2.5% 0.41% 0.455% 0.20% 0.61%

[0155] After each dosage, the corresponding yarn was collected and knitted fabrics equivalent in structure to the first one made were prepared. Each of the fabrics was placed in the sample holder of the spectrophotometer and readings were made.

[0156] The results of the color difference obtained by comparison with the initial sample of colored yarn (made of polyester polymer and 2.5% by weight of solid-M) were as follows in Tables 8-11 for yellow, red, green, and blue, respectively. In each Table, the first measurements are of the composition with only solid masterbatch, followed by the composition also including liquid masterbatch, followed by color difference between the two compositions (assessed under three different illuminants).

TABLE-US-00010 TABLE 8 Dose of Yellow-L-M (Yellow-liquid-masterbatch) Ilum./Obs. L* a* b* Sample Colored synthetic yarn composition: Polyester polymer + 2.5% wt. of solid-M D65 10 Deg 32.73 0.36 1.01 Sample + dose of correcting liquid-M, expressed in wt. (dose of Yellow-L-M) 0.06% D65 10 Deg 32.75 −0.09 2.63 0.12% D65 10 Deg 32.68 −0.45 4.19 0.24% D65 10 Deg 32.46 −1.04 7.02 0.40% D65 10 Deg 32.21 −1.59 9.91 Color Difference CIE LAB Sample + dose of correcting liquid-M, expressed in wt. (dose of Yellow-L-M) Ilum./Obs. ΔL*/SL Δa* Δb* CIE ΔE 0.06% D65 10 Deg 0.02 −0.46 1.61 1.82 0.06% A 10 Deg 0.08 −0.08 1.62 1.75 0.06% F11 10 Deg 0.09 −0.34 1.78 1.93 0.12% D65 10 Deg −0.05 −0.81 3.17 3.27 0.12% A 10 Deg 0.07 −0.1 3.19 3.19 0.12% F11 10 Deg 0.03 −0.54 3.43 3.48 0.24% D65 10 Deg −0.27 −1.41 6.01 6.19 0.24% A 10 Deg 0.05 −0.12 6.05 6.06 0.24% F11 10 Deg −0.01 −0.94 6.51 6.59 0.40% D65 10 Deg −0.52 −1.95 8.9 9.11 0.40% A 10 Deg −0.3 −0.14 8.94 8.95 0.40% F11 10 Deg −0.34 −1.29 9.63 9.72

TABLE-US-00011 TABLE 9 Dose of Red-L-M (Red-liquid-masterbatch) Ilum./Obs. L* a* b* Sample-Colored synthetic yarn composition: Polyester polymer + 2.5% wt. of solid-M D65 10 Deg 32.56 0.35 0.98 Sample + dose of correcting liquid-M, expressed in wt. (dose of Red-L-M) 0.09% D65 10 Deg 30.81 0.91 0.18 0.17% D65 10 Deg 30.16 1.47 −0.44 0.34% D65 10 Deg 29.41 2.68 −1.6 0.57% D65 10 Deg 27.77 3.9 −2.6 Color Difference CIE LAB Sample + dose of correcting liquid-M, expressed in wt. (dose of Red-L-M) Ilum./Obs. ΔL*/SL Δa* Δb* CIE ΔE 0.09% D65 10 Deg −1.75 0.57 −0.79 2 0.09% A 10 Deg −1.74 0.65 −0.73 2 0.09% F11 10 Deg −1.67 0.7 −0.67 1.93 0.17% D65 10 Deg −2.4 1.12 −1.42 3.01 0.17% A 10 Deg −2.38 1.27 −1.29 2.99 0.17% F11 10 Deg −2.23 1.33 −1.18 2.85 0.34% D65 10 Deg −3.15 2.33 −2.57 4.68 0.34% A 10 Deg −3.07 2.58 −2.28 4.61 0.34% F11 10 Deg −2.89 2.75 −2.23 4.57 0.57% D65 10 Deg −4.79 3.55 −3.57 9.11 0.57% A 10 Deg −4.65 3.83 −3.08 8.95 0.57% F11 10 Deg −4.44 4.14 −3.14 9.72

TABLE-US-00012 TABLE 10 Dose of Green-L-M (Green-liquid-masterbatch) Ilum./Obs. L* a* b* Sample Colored synthetic yarn composition: Polyester polymer + 2.5% wt. of solid-M D65 10 Deg 32.22 0.34 0.99 Sample + dose of correcting liquid-M, expressed in wt. (dose of Green-L-M) 0.08% D65 10 Deg 31.98 −0.59 0.82 0.16% D65 10 Deg 31.84 −1.5 0.66 0.32% D65 10 Deg 31.37 −3.05 0.45 0.53% D65 10 Deg 30.66 −4.68 0.21 Color Difference CIE LAB Sample + dose of correcting liquid-M, expressed in wt. (dose of Green-L-M) Ilum./Obs. ΔL*/SL Δa* Δb* CIE ΔE 0.08% D65 10 Deg −0.23 −0.93 −0.17 0.97 0.08% A 10 Deg −0.35 −1.01 −0.41 1.14 0.08% F11 10 Deg −0.29 −0.99 −0.25 1.06 0.16% D65 10 Deg −0.37 −1.84 −0.33 1.91 0.16% A 10 Deg −0.6 −2 −0.8 2.24 0.16% F11 10 Deg −0.49 −1.98 −0.48 2.1 0.32% D65 10 Deg −0.84 −3.39 −0.54 3.53 0.32% A 10 Deg −1.26 −3.66 −1.41 4.12 0.32% F11 10 Deg −1.08 −3.6 −0.82 3.85 0.53% D65 10 Deg −1.56 −5.01 −0.78 5.31 0.53% A 10 Deg −2.17 −5.41 −2.07 6.18 0.53% F11 10 Deg −1.9 −5.32 −1.18 5.77

TABLE-US-00013 TABLE 11 Dose of Blue-L-M (Blue-liquid-masterbatch) Ilum./Obs. L* a* b* Sample Colored synthetic yarn composition: Polyester polymer + 2.5% wt. of solid-M D65 10 Deg 32.6 0.32 0.91 Sample + dose of correcting liquid-M, expressed in wt. (dose of Blue-L-M) 0.07% D65 10 Deg 31.54 −1.95 −0.25 0.14% D65 10 Deg 30.81 −3.41 −1.5 0.27% D65 10 Deg 28.83 −5.07 −3.15 0.46% D65 10 Deg 27.84 −6.85 −4.92 Color Difference CIE LAB Sample + dose of correcting liquid-M, expressed in wt. (dose of Blue-L-M) Ilum./Obs. ΔL*/SL Δa* Δb* CIE ΔE 0.07% D65 10 Deg −1.05 −2.27 −1.16 2.76 0.07% A 10 Deg −1.4 −2.78 −1.77 3.58 0.07% F11 10 Deg −1.23 −2.38 −1.46 3.05 0.14% D65 10 Deg −1.78 −3.73 −2.41 4.79 0.14% A 10 Deg −2.39 −4.49 −3.46 6.15 0.14% F11 10 Deg −2.07 −3.92 −2.89 5.29 0.27% D65 10 Deg −3.76 −5.39 −4.06 7.72 0.27% A 10 Deg −4.68 −6.47 −5.65 9.78 0.27% F11 10 Deg −4.19 −5.58 −4.79 8.46 0.46% D65 10 Deg −4.75 −7.17 −5.83 10.39 0.46% A 10 Deg −6.01 −8.64 −8.03 13.24 0.46% F11 10 Deg −5.37 −7.23 −6.87 11.33

[0157] It can be seen that the biggest difference of Δa is with Blue-M-L, followed by Green-M-L and the one that varies least is the Yellow-M-L. And the biggest difference of Δb is with Yellow-M-L, followed by Blue-M-L and the one that varies least is Green-M-L.

[0158] FIGS. 1 and 2 show with more detail the variation of the coordinate “a*” and the coordinate “b*” as result of the dosage of the liquid masterbatch composition. As can be seen in the two Figures, the behavior is practically linear. Both with the Yellow-L-M as with Green-L-M it can be seen that they are very selective in their effect: Yellow-L-M practically only affects the coordinate b, and Green-L-M practically only affects the coordinate a. In the case of Red-L-M and of Blue-L-M the color variation affects the two coordinates in a very important way. In many cases, these deviations may be desirable.

[0159] Nevertheless, if only is required to correct one coordinate, then, it can be done by combining two correcting liquid masterbatch compositions according to the following indications: To correct coordinate “a” in the positive sense without any change in the coordinate “b”, it is sufficient to dose the required red-L-M with a small proportion of yellow-L-M. Usually 1/10 of the red amount in yellow would be correct; and to correct coordinate “b” in the negative sense without any change in the coordinate “a”, it is sufficient to dose the required blue-L-M with a similar amount of red-L-M.

Example 2: Correction System by Using a Correcting Liquid-Masterbatch Composition in a Fusion Spinning Process

[0160] The polymer support was polyester having a solid masterbatch and a liquid masterbatch dispersed therein. The solid-M was prepared as in Example 1. The liquid-M was prepared with a mixture of inert oils and 38% wt. of pigment GREEN (P.G.7).

[0161] Spinning a polyester yarn was carried out by dosing 2.5% wt. of solid masterbatch and 0.079% wt. of liquid masterbatch. The extruded yarn was textured by air. Then, a fabric was knitted from this yarn. This fabric was placed in the sample holder of a Datacolor 650 spectrophotometer. Averaged readings were made in the spectrophotometer to determine the coordinates L, a* and b*. The results for illuminant D65 10 Deg are included in Table 12 below. These readings of the coordinates a* and b* were not within the tolerances of the desired target hue color coordinates, see target hue color row.

[0162] To correct the actual color hue to the target color hue, a dose of 0.237% wt. of green-L-M was added as correcting-liquid-masterbatch to the molten polyester mass during the extrusion. The extruded yarn was textured by air. Then, a fabric was knitted from this yarn. This fabric was placed in the sample holder of a Datacolor 650 spectrophotometer. Averaged readings were made for the corrected sample in order to verify that the color hue is within limits of tolerances.

[0163] After color hue correction of the sample, the corrected hue color corresponded to the target color hue (a*: −3.05 (−0.59-2.46), b*: 0.45 (0.82-0.37)). The correction did not generate metamerism, and the color hue differences, if any, were imperceptible to the healthy human eye.

TABLE-US-00014 TABLE 12 Comparison of Corrected Color Hue Sample to Target Color Hue Ilum./Obs. L* a* b* Sample: Colored D65 10 Deg 31.98 −0.59 0.82 synthetic yarn composition: Polyester polymer + 2.5% wt. of solid- M + 0.079% wt. of liquid-M Target hue color D65 10 Deg 31.37 −3.05 0.45 Color Difference CIE Lab: Sample + dose of correcting liquid-M, expressed in wt. (Dose of Green-L-M) Ilum./Obs. ΔL*/SL Δa* Δb* CIE ΔE +0.237% D65 10 Deg −0.61 −2.46 −0.37 2.56 A 10 Deg −0.91 −2.65 −1.00 2.97 F11 10 Deg −0.79 −2.61 −0.57 2.79

[0164] The invention is not limited to the above embodiments. The claims follow.