MXPA00002650A - Melt spinning colored polycondensation polymers - Google Patents

Abstract

The invention is a method of coloring melt spun condensation polymers while avoiding hydrolytic degradation and maintaining the melt viscosity of the polymer. The method comprises adding a liquid dispersion of a colorant to the melt phase of a condensation polymer, and in which the amount and type of the liquid in the dispersion will not substantially affect the melt viscosity of the condensation polymer;and thereafter spinning the colored melt phase condensation polymer into filament form. In another aspect the invention is a polyester filament comprising polyethylene terephthalate, a colorant, and a nonaqueous organic liquid that is soluble in melt phase polyester, and has a boiling point above 300°C, but that otherwise does not modify the polymer chain.

Description

CONDENSATION POLYMERS FOR FUSED SPYING WITH COLOR FIELD OF THE INVENTION The present invention relates to methods for dyeing synthetic polymer filaments in order to form respective colored yarns or fabrics, and in particular it relates to a method for melt spinning polycondensation polymers that are dyed using dispersions. colored liquid, and filament, threads and resultant dyed polymer fabrics. • BACKGROUND OF THE INVENTION Synthetic fibers are used in a wide variety of textile applications that include clothing and other cloth items which, although in many circumstances are desired in white or natural color, are also desirably manufactured and distributed in a variety of colors and patterns • in other circumstances. As it is known for those related to the techniques textiles, various techniques are used to add color to textile products. In general, these techniques add that color to the basic structures of textile products: fibers, yarns made of fibers, and fabrics made of yarns. Thus, certain techniques dye individual fibers before they are formed into yarns, other techniques dye yarns before they are formed into fabrics and other techniques dye woven or knitted fabrics. There are particular advantages and disadvantages associated with the choice of each staining technique. Some examples of definitions and explanations about dyes and staining techniques are set out in the Dictionary of Fiber & Textile Technology (1990), published by Hoechst-Celanese Corporation, on pages 50-54. Although the term "dye" is often used in a generic sense, those related to textile processes recognize that the term "dye" most adequately describes a dye that is soluble in the material being dyed, and that the term "dye" "It should be used to describe insoluble dyes. Because polyester, particularly polyethylene terephthalate ("PET"), is so widely used in textile applications, there is also a wide range of needs for dyeing polyester such as filament, yarn or cloth. Although under some circumstances, dyed yarns and fabrics are convenient and desirable, dyeing the initial fiber offers certain performance benefits such as improved speed. As an additional and increasingly important consideration, dyeing filament instead of yarns and fabrics tends to reduce the side effects that must be faced to avoid air and water contamination that might otherwise be associated with various staining procedures. Conventionally, a "master batch" method has been used to dye fibers (or filaments) during the melt spinning process. As is known for those related to this technique, in the masterbatch process, the desired colorant is dispersed at a relatively high concentrated level within a carrier polymer. In a next step of the process, the master batch of the highly concentrated dye polymer is introduced into the melt spinning system of the polymer and mixed with a virgin polymer in a ratio which fortunately reaches the desired color. However, condensation polymers offer particular challenges for the master batch system. As is known for those related to chemical reactions, a condensation polymer results from a reaction in which two monomers or oligomers react to form a polymer and a water molecule. Because such reactions produce water, they are referred to as "condensation" reactions. However, due to chemical equilibrium, the water must be continuously removed from the polycondensation reaction, otherwise it tends to direct the reaction in the other direction; that is, depolymerize the polymer. This results in a loss of molecular weight in the polymer which is referred to as a hydrolytic degradation. In particular, the molecular weight (measured by the intrinsic viscosity or "VI") of the polyester can easily be decreased by 0.15 dl / g (0.55-0.75 dl / g is considered a good viscosity for filament). As a major problem - and one that becomes evident during the subsequent processing of the filament and yarn - the loss in VI is very variable depending on the quality of the process control of the drying and extrusion systems of the master batch. In particular, obtaining the required color specification of the masterbatch pickup sometimes requires re-extruding the polymer to obtain a desired color correction. Unfortunately, such re-extrusion for the purposes of color matching tends to increase the additional molecular weight loss. The "pellet" of the masterbatch is generally introduced into the spinning process using several options each of which tends to provide an extra source of variation for the resulting molecular weight. Because there are several steps of the procedure during which molecular weight can be lost, the effect tends to be cumulative and significant. The overall effect is a significant reduction in the molecular weight of the filament that manifests itself as a variability of orientation in the resulting yarn. In turn, the variability of orientation produces a resultant variability in the physical properties of the yarn, such as extension, tenacity and stretching force. Such variability in the physical properties of the woven yarn generates several additional problems. For example, the partially oriented yarn (POY) which is textured by stretch must show uniform stretching force to ensure that its pre-aggregate tension remains within the desired specifications. If the properties of the yarn are outside such specifications, various problems occur such as loosening by twisting and yarn processing at commercial speeds is avoided. Moreover, the stretch performance of the woven yarn, whether POY, low orientation fabrics (LOY), fully oriented fabrics (FOY) or short fiber, depends to a large extent on a consistent elongation since the stretch ratio imposed can not Exceed the extension of the woven thread (measured by elongation). In addition, the consistent physical properties of the • 5 final stretch or filament with stretch texture for optimal performance of fabrics and other end-use products. EP 794222 discloses a dispersible additive for polymeric materials consisting of pigments coated with dispersant in a non-aqueous liquid polymeric carrier. EP 794222 also describes a composition polymer containing additive consisting of a polymeric host and a • additive system dispersed according to the above in the entire polymeric host. In addition, EP 794222 discloses a method for making pigmented filaments comprising (i) supplying a melt flow of a melt spinning polymer host into spinner holes; (ii) incorporate an additive according to the above, in the fusion of the host upstream of the spinner holes; and (iii) extruding a melt of the mixture through spinner holes to form pigmented filaments; and a method for continuously producing sequential lengths of meltblown filaments containing different additives. EP 266754 describes compositions for mass coloration of polyesters. The compositions consist of 100 parts by weight of a pigment and / or dye and 42-2000 parts by weight of a dispersion medium with an OH number of not more than 25 mg KOH / g. The dispersion medium is (a) a liquid with a molecular weight of at least 700 and a viscosity of up to 150 Poises at 25 ° C and / or (b) a liquid polyester. The compositions contain 100-1500 parts by weight of the dispersion medium and 0-1400 parts by weight of an inorganic filler. The dispersion medium is (a) a polyether, a bisphenol A derivative, a polyester ether, or a liquid polyester of OH terminal entangled with a • 5 aliphatic diisocyanate; or (b) a copolymer of an aliphatic dicarboxylic acid and an alkylene glycol, or an aliphatic polyester with at least one terminal group blocked with a monohydric alcohol. In a practical sense, the variation in physical properties from filament to filament, fiber to fiber and thread to thread, forces the various 10 processes and machinery for textile manufacturing to be continuously • readjusted whenever a fiber or colored yarn is introduced. Thus, the problems inherent to masterbatch staining tend to raise the cost and decrease the productivity of subsequent textile processes incorporating fibers and yarns dyed from master batch. BRIEF DESCRIPTION OF THE INVENTION Therefore, it is an object of the present invention to provide a method for adding dye to a polyester and other condensation polymers while in the melting phase but without adversely reducing the molecular weight and resulting properties in the manner in which they are reduced by conventional methods.

The invention achieves this object with a method of dyeing condensation polymers for melt spinning while avoiding hydrolytic degradation and maintaining the melt viscosity of the polymer. The method consists of adding a liquid dispersion of a dye to the phase • 5 fused from a condensation polymer and in which the amount and type of the liquid in the dispersion will not substantially affect the melting viscosity of the condensation polymer, and subsequently spin the condensation polymer in the melting phase dyed to form a filament .

BRIEF DESCRIPTION OF THE DRAWINGS • The foregoing and other objects and advantages of the invention will become more apparent when taken together with the detailed description and the accompanying drawings in which: Figure 1 is a schematic diagram of a conventional master batch process for producing batch tablet teacher; Figure 2 is another conventional method for using a master batch process to produce dyed filament; Figure 3 is a schematic diagram of the liquid dispersion technology with color of the present invention; Figure 4 is a graph of the pre-aggregate stresses taken during a plurality of filament samples produced according to the present invention and according to conventional master lot procedures; Figure 5 is a graph of Dynafil and stress responses per operation taken during various samples of the present invention; • Figure 6 is a graph of color uniformity taken over several samples of the present invention; Figure 7 is a graph of the breaking force taken during several samples of the present invention; Figure 8 is an extension graph taken during several samples of the present invention; and • Figure 9 is a tenacity graph taken during several samples of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for dyeing a condensation polymer for melt spinning while preventing hydrolytic degradation. • and the melt viscosity of the polymer is maintained, and represents a significant improvement over conventional master batch processes. Such Methods are illustrated schematically in Figures 1 and 2. Figure 1 schematically illustrates the manufacture of a master batch tablet. The pellet of a dryer 10 and the pigments or dyes of a hopper or other source 11 are added to a desired mixture using a suitable mixer 12 or similar device to an extruder 13 which is conventionally a single or twin screw extruder. The source pellets of the dryer 10 are the same as the polymer from which the eventual filament is made. Thus, the polyester pellets are used to form the master batch for • 5 strands of polyester and nylon 6 or 66 nylon pads are used as the master batch pads for those polymers. As mentioned in the background, the color source, whether pigment, colorant or some other, is normally mixed with the polymer pellet in a moderately high proportion to form a relatively high color concentration. The polymer that is extruded is then tempered and made into a pellet in a suitable equipment designated as 14 to produce a masterbatch which is concentrated with the pigment or dye in amounts of between about 10 and 50% by weight . Figure 2 illustrates the manner in which the master batch is added to the virgin polymer to form the final dyed filament. The master batch tablet produced in Figure 1 is designated as 15 in Figure 2 and is normally distributed from a dryer 17. The "base" polymer pellet is • distributes from another dryer 16 which is mixed from the master batch tablet. There are several options for mixing the master batch with the pill base. In the first option, the master batch 15 is sent to a dryer 17 from which it is mixed in a suitable mixing device 20 with the base tablet and then sent to the extruder 21. As indicated by dotted line 22, in FIG. an alternative method, the master batch pad 15 is mixed directly with the base pad and avoids the dryer 17. In either of these options, the master batch pad and the base pad are mixed in an extruder from which they go to a system multiple designated as 23 and then to a suitable block, portion and spinner designated together as 24, from which the polymer is spun into filaments 25 and then sent to an appropriate shrinkage system 26. Alternatively, the tablet Master batch of the dryer 17 can be sent to a sidestream extruder 27 and subsequently pumped by the pump 28 to be mixed with the extruded base polymer just before the multiple system 23. The Figure 3 illustrates the contrast method of the present invention. As shown therein, the base pellet is taken again from a dryer 30 and sent directly to the extruder 31. However, instead of preparing a masterbatch, the method of the invention comprises adding a liquid dispersion 32 of the colorant. directly to the base pellet polymer either in an extruder or just before the multiple system. As illustrated in Figure 3, the liquid dispersion 32 can be pumped by the pump 33 either to the extruder 31 or to a point just before the multiple system which is designated as 34. Subsequently, the dyeing condensation polymer of the The melt is spun to form a filament using a block, portion and spinner designated as 35 from which the filaments 36 are sent to an adequate shrinking system 37 which normally includes several finishing and packaging steps.

Of course, the invention is equally useful in direct coupling continuous spinning and polymerization systems which omit the chip making and extrusion steps and instead lead the polymerized melt directly to the spinner. In such cases, the liquid dispersion of the dye • 5 can be added to a multiple system before the spinner as illustrated by number 34 in figure 3. For those related to textile techniques they will recognize that the terms "spinning" and "spinning" are commonly used to refer two different procedures. In a sense, "spinning" refers to the manufacture of a filament melting phase polymer. In the other sense, "spinning" refers to the process for manufacturing short fiber or twist yarns. Both "spinning" senses are used in the present, and will be readily recognized in the context by those skilled in the art. In the preferred embodiments, the step of adding the dispersion Liquid dye comprises the addition of a dispersion in which the liquid is organic, non-aqueous, soluble in polyester and has a boiling point above the melting point of the polyester (or other condensation polymer). For • use with polyester, preferably the liquid has a boiling point above about 300 ° C. The high boiling point of the dispersion liquid It helps prevent gas from being generated in the polymer stream at the melt viscosity temperatures. As mentioned above, condensation polymers that can be dyed according to the present invention may include polyethylene terephthalate, polybutylene terephthalate, poly (trimethylene) terephthalate, other polyesters, nylon 6 and nylon 66. Preferably, the dye consists of a thermally stable dispersed dye or thermally stable pigment, and the • 5 combination of liquid dye in the dispersion to have good wetting properties with respect to each one. The following tables illustrate the comparative advantages of the present invention. Table 1 and table 2 are related because table 1 summarizes the more detailed information presented in table 2. As demonstrates Table 1, six types of filament examples were compared • polyester that were dyed according to the invention using red dye against standard control filaments. The yarns were compared as partially oriented yarns (POY), flat stretch yarn, and stretch textured yarn (DTX). When compared to POY, the results Dynafil and? ELAB were very favorable. As shown in table 1, the largest? E ab was 0.58. Although color comparisons are necessarily subjective, those related to staining procedures are aware that an? E ab of 1.0 or less is generally considered a very good color conjunction. With respect to the flat stretch yarn, the breaking forces are all very similar and in fact the difference between the standard and the samples according to the invention is almost insignificant from the statistical point of view. Similarly, the extension in breaking and tenacity for the flat stretch yarn according to the invention is favorably comparable with, and in fact almost identical to that of the standard undyed yarn. Stretch textured yarn showed similar consistency properties between breaking strength, extension and tenacity. Table 3 shows some properties for conventionally dyed yarns and not according to the present invention. Table 4 compares the data of the conventionally dyed yarn of table 3 with dyed yarn according to the present invention of tables 1 and 2. It will be noted that in each the pre-aggregate tension (T1) of the yarn formed according to the invention • is significantly superior to conventionally dyed yarn. More importantly, the standard deviation and difference scale of the average is smaller for the liquid matrix technology of the present invention as compared to conventionally dyed yarns. This uniformity between yarns produced according to the present invention is one of the main advantages of the present invention in which various types of spinning, braiding and weaving machinery do not need to be readjusted continuously to f consider the differences in mechanical properties between the yarns dyed in a conventional manner. Instead, the uniform physical properties in threads The dyeings offered by the present invention provide the end user with the opportunity to use a variety of different colors of the same yarn with the knowledge that the yarn will be consistent in color to color.

Figures 4 to 9 are graphs of certain data from tables 1 to 4. In particular, Figure 4 depicts the pre-aggregate tensions for five yarns dyed according to the present invention and seven dyed in a conventional manner. As shown in figure 4, the yarn tensions according to The present invention is remarkably consistent, while the tensions of conventionally dyed yarns vary on an unpleasantly wide scale. Figure 5 shows the consistency in Dynafil measurements, post-aggregate tension and the ratio of pre- and post-aggregate stresses as well as the consistency in the pre-aggregate tension. • Figure 6 represents the color uniformity data of Table 3. Figures 7, 8 and 9 demonstrate respectively the excellent performance of the yarn in terms of breaking strength, extension and tenacity, each of which is also summarized in the picture. fifteen • • TABLE 1 Uniformity batch to batch; Summary of Table 2 Six Lots of a Single Product (Red) Including Standard Not Dyed I heard r O I heard I heard TABLE 2: Uniformity Batch to Lot Six Batch of Simple Product (Red) According to the Invention includes non-dyed type s > • • fifteen • twenty • 15 • 20 TABLE 3 Seven Lots of a Simple Texture Color Produced Using Conventional Technology • • TABLE 4 Five Colors Produced According to the Invention and Seven Lots of a Simple Color Produced Conventionally fifteen twenty TABLE 5 Six Lots of Simple Product According to Invention Compared with Seven Lots of Simple Product According to Conventional Technology • • TABLE 6 Comparison between Nylon Fiber 6 Stained According to Invention and Control The application to another polycondensation polymer, nylon 6 was demonstrated (Table 6). The yarns were spun at 2000 mpm to produce a 240 denier yarn with 34 filaments. These were subsequently stretched at 150 ° C with a draw ratio of 2.00. The results contrasting the unmodified control with the invention, produced using 0.30% olive-colored addition are given in Table 6. No processing difficulties were encountered as a result of the color addition, and it is easily observed that no there are significant differences between the nominal fiber properties. In the most preferred modalities, the liquid dispersion f 10 (also referred to as "liquid matrix") is available from Colormatrix Corporation, 3005 Chester Avenue, Cleveland, Ohio 44114 and designated Colormatrix LCPY-1: Series 82-89. According to the material safety data sheet (MSDS) of Colormatrix Corporation, the preferred embodiment comprises various oils, esters, pigments and dyes of which the principal ingredient is refined hydrocarbon oil with various non-toxic pigments and dyes. According to MSDS, the product does not contain hazardous ingredients as defined by the OSHA risk communication standard (29 CFR 1910.1200). The preferred liquid has a boiling scale at atmospheric pressure of at least 260 ° C, an insignificant vapor pressure under the same conditions, a specific gravity between 958.63 and 2156.92 gr / l and is insoluble in water. The liquid is chemically stable and risk polymerization does not occur. The liquid is non-corrosive with respect to metals, but it is an oxidant. The product is considered an "oil" under the Clean Water Act.

The product does not contain any toxic chemicals that could be subject to the SARA Title III Section 313 and 40 CFR Part 372 reporting requirements. In another embodiment, the invention consists of a resulting polyester filament that includes polyethylene terephthalate, the coloration and the non-aqueous organic liquid. One of the advantages of the present invention is that the resulting filament is essentially identical in its physical properties to the non-dyed polyester filament (or other condensation polymer). Thus, from the point of view of the end user, the properties of the filament are advantageously consistent with those of the polyesters, and in fact more consistent than the f 10 of the dyed polyester filaments using master lot procedures. However, the filament does not contain the non-aqueous organic liquid of the original liquid dispersion. The nature of the liquid is such that it remains in the polymer matrix, but does not otherwise interfere with or modify the polymer chain. Therefore, an adequate analysis of the filament of According to the present invention, it shows that it includes polyethylene terephthalate, a dye and the non-aqueous organic liquid. In another embodiment, the invention comprises a short cut fiber f of the filament of the present invention and yarns formed from the short fiber. As with other polyesters, the filament and fiber can be textured and the The fiber can be mixed with other fibers than polyethylene terephthalate in another conventional way to form fabrics, usually woven or knitted fabrics, from those yarns and fibers.

Although the invention has been explained with reference to its preferred embodiments, it will be understood that various modifications thereof will be apparent to those skilled in the art upon reading the specification, therefore, it will be understood that the invention described herein encompasses such 5 modifications to the extent that they fall within the scope of the appended claims.

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Claims (32)

1. NOVELTY OF THE INVENTION CLAIMS 1. - A method for dyeing melt-spun condensation polymers while avoiding hydrolytic degradation and maintaining the melt viscosity of the polymer, the method consists in: adding a liquid dispersion of a dye to the melt phase of a condensation polymer and in wherein the amount and type of liquid in the dispersion will not substantially affect the melt viscosity of the condensation polymer, and subsequently spin the melt polymer in the dyed melt phase to form a filament.
2. 2. A staining method according to claim 1, further characterized in that the step of adding the liquid dye dispersion comprises the addition of a dispersion in which the liquid is soluble in the condensation polymer.
3. 3. A staining method according to claim 1, further characterized in that the step of adding the liquid dye dispersion comprises the addition of a dispersion in which the liquid has a boiling point above the melting point of the polymer of condensation.
4. 4. A staining method according to claim 1, further characterized in that the step of adding the liquid dispersion to the condensation polymer comprises the addition of the dispersion to a polymer selected from the group consisting of: polyethylene terephthalate, terephthalate polybutylene, poly (trimethylene) terephthalate, other polyesters, nylon 6 and nylon 66.
5. 5. A staining method according to claim 1, further characterized in that the step of adding the liquid dispersion to the condensation polymer f 5 comprises the addition of a dispersion in which the liquid has good wetting properties with respect to the colorant.
6. 6. A staining method according to claim 1, further characterized in that the condensation polymer consists of polyethylene terephthalate. f 10 7. A staining method according to claim 1 or claim 6, further characterized in that the step of adding the liquid dye dispersion comprises the addition of a dispersion in which the liquid is organic and non-aqueous. 8. A staining method according to claim 1 or claim 6, further characterized in that the step of adding the liquid dispersion to the melting phase comprises the addition of the dispersion to the melting phase while the melting phase It is in an extruder. 9. A staining method according to claim 1 or claim 6, further characterized in that the step of adding the dispersion Liquid to the melting phase comprises the addition of the dispersion to the melting phase after the melting phase leaves the extruder, and before the melting phase is spun into filament. 10. - A staining method according to claim 6, further characterized in that it comprises the steps for drying the polyester in the form of a pellet and melting the dried polyester pellet in an extruder before the addition step of the liquid dispersion. 11. A staining method according to claim 1, further characterized in that the step of adding the liquid dispersion consists of: adding a polyester pellet to a spinning system fed by extruder; and adding the liquid dispersion of a dye to the spinning system fed by extruder before spinning the melt of the extruder. 12. A method for spinning polyester according to claim 11, further characterized in that the step of adding the liquid dispersion comprises the addition of the dispersion to the pellet feed of the spinning system fed by extrusion. 13. A method for spinning polyester according to claim 11, further characterized in that the step of adding the liquid dispersion comprises the addition of the dispersion to the molten polyester stream produced by the extruder. 14. A method for spinning polyester according to claim 11, further characterized in that the step of spinning the filament-dyed polyester 20 comprises directing the molten polyester from the extruder to a spinner. 15. A method for spinning polyester according to claim 14, further characterized in that it comprises directing the molten polyester of the extruder to a manifold, and of the manifold to a plurality of spinners. 16. A method for spinning polyester according to claim 6 or claim 11, further characterized in that the step of adding the liquid dye dispersion comprises the addition of a dispersion in which the liquid is soluble in polyester. 17. A method for spinning polyester according to claim 1, claim 6 or claim 11, further characterized in that the step of adding the liquid dye dispersion comprises the addition of a dispersion in which the liquid has a higher boiling point to 300 ° C. 18. A method for spinning polyester according to claim 1, claim 6 or claim 11, further characterized in that the step of adding the liquid dye dispersion comprises the addition of a dispersion in which the dye consists of a thermally dispersed dye stable or a thermally stable pigment. 19. A method for spinning polyester according to claim 1, claim 6 or claim 11, further characterized in that the step of adding the liquid dispersion to the polyester comprises the addition of a dispersion in which the liquid has good wetting properties with regarding the colorant. 20. A method for spinning polyester according to claim 1, claim 6 or claim 11, further characterized in that the step of adding the liquid dye dispersion comprises the addition of a dispersion in which the liquid is a refined hydrocarbon oil . 21. A method for spinning polyester according to claim 1, claim 6 or claim 11, further characterized f 5 because the step of adding a finish to the dyed polyester filament. 22. A method for spinning polyester according to claim 1, claim 6 or claim 11, further characterized in that the step of winding the dyed polyester filament in a package. 23. A method for spinning polyester in accordance with the f 10 claim 1, claim 6 or claim 11, further characterized in that it comprises cutting the polyester filament dyed in short fibers. 24. A method for spinning polyester according to claim 1, claim 6 or claim 11, further characterized in that it comprises the step of giving texture to the dyed polyester filament. 15 25.- A polyester filament consisting of: polyethylene terephthalate, a coloring agent and a non-aqueous organic liquid that is soluble in polyester of melting phase and has a boiling point higher than 300 ° C, but that of another form does not modify the polymer chain. 26. A polyester filament according to claim 20, further characterized in that said coloring agent is selected from the group consisting of dye and dispersed pigments. 27. - A polyester filament according to claim 25, further characterized in that said non-aqueous organic liquid consists of a refined hydrocarbon oil. 28. A texturized polyester filament according to claim 25. 29. A short fiber cut from the filament according to claim 25 or claim 28. 30.- A yarn comprising the short fiber according to claim 29 31. A yarn according to claim 30 and further comprising a mixture of fibers different from polyethylene terephthalate. 32. A fabric consisting of threads according to claim 30 or claim 31.