US3485574A - Polyester and olefin yarns with basic resins therein wound on core,steamed and acidified with so2 or no2 - Google Patents

Description

United States Patent ice the Public H Int. Cl. D06m 3/20 US. Cl. 8-115.5 4 Claims ABSTRACT OF THE DISCLOSURE The process of uniformly exposing the surface of a polyhydrocarbon or polyester yarn to an acid treatment comprising subjecting said yarn, which has been moistened with water, as by steaming and wound upon a core, to a vacuum and subsequently subjecting said yarn to an atmosphere of an acid anhydride vapor, such as S0 or N0 This invention relates to an improved process for the uniform acid treatment of yarns.

The co-pending patent applications Ser. No. 375,328 filed June 15, 1964, now Patent No. 3,361,843 and Ser. No. 352,317 filed Mar. 16, 1964, now Patent No. 3,432,- 250 of Robert Miller, Milton Father and Frederick C. Loveless disclose processes for rendering synthetic yarns composed predominantly of inherently undyeable hydrocarbon or polyester high polymers deeply dyeable with acid type dyes by first incorporating in said hydrocarbon or polyester high polymer a quantity of a highly polar basic polymer and, subsequent to the extrusion of the fibers from the polymeric composition, uniformly treating the surface of the fibers with an acidic reagant which reacts with some of the highly polar basic polymer at and near the fiber surfaces. The treatment with the acidic reagent converts a fiber which is only faintly dyeable with acid type dyes to one which can readily be dyed to very deep shades by such types of dyes. So sensitive is such fiber to this acid activation treatment that wherever it is not treated with the acidic reagent to a point of substantial equilibrium, variations in depth of color occur when the fiber is dyed. Thus it is essential to the success of the processes disclosed in the said copending applications that the activation treatment with the acidic reagant be performed with a high degree of uniformity.

Activation treatment procedures involving the continuous passage of the fiber in yarn form through a liquid bath of the acidic reagant is frequently highly uneconomical because of the amount of activating reagant carried off on the fiber and because of the cost of rewinding. Batchwise procedures for contacting packages of the yarn wound on cores with the acidic reagent have inevitably required special precautions with attendant additional cost to avoid non-uniformity in the activation of the yarn package. 'One such expedient is to wind the yarn on specially constructed perforated cores in order to assure uniformity of activation when such yarn packages are immersed in a liquid bath of acidic reagant. The rewind-- ing operation to and from such specially prepared cores adds considerably to the cost of the yarn. Other expedients involve tedious and expensive procedures for circulating the acidic reagant through the packages of yarn.

It is an object of this invention to achieve uniform treatment of yarn wound onto packages by reagents in the vapor state. It is a further object of this invention uniformly to treat yarn wound upon cores with reagants in 3,485,574 Patented Dec. 23, 1969 the vapor state which combine with water to form acids. It is a still further object of this invention to achieve such treatment without the need for winding the yarn upon specially constructed cores or for unwinding the yarn from the package in which it is subjected to the treatment.

These objects, and others which will become apparent from a consideration of this specification, can be achieved by winding the yarn to be treated in uniformly moistened condition, upon a core, evacuating the volume surrounding the said core and subsequently subjecting the yarn thus wound upon the core to an atmosphere of an acid anhydride which, upon combining with the moisture on the fiber, forms the acid which activates the fiber. The atmosphere of acid anhydride is maintained in contact with the yarn until equilibrium with the moisture is achieved, i.e. until no further reduction in pressure due to reaction of the acidic reagnat with moisture occurs.

The moisture content of the yarn subjected to treatment by the acid anhydride in the process of this invention must be at least approximately 1% O.W.F. (on weight of fiber) in order to result in uniform activation of a marked degree. Ideally, however, the moisture content will be 5% O.W.F. or even higher.

The correct moisture content of the fiber or yarn may be achieved by depositing water upon the yarn either before it is wound upon the core or thereafter. Inasmuch as the yarn is generally coated with a fiber finish dis persed or dissolved in water after the spinning and drawing steps are completed, it is frequently convenient to apply this finish solution or dispersion in such a fashion that the correct quantity of water remains upon the yarn as it is wound upon the core into a package. Care must then be exercised to prevent this moisure from evaporating during the interval between the finishing operation and the activation treatment of this invention. One convenient way to avoid such drying out is to store the packages in polyethylene bags.

If the yarn has not been wound upon cores with a sufiicient amount of moisture, or if some has evaporated, this moisture can be imparted to the yarn by treating the yarn package with steam before the vacuum is applied. The steam may be saturated or superheated, but its temperature should not exceed the temperature above which yarns of the character to be treated tend to undergo excessive shrinkage, which is C. in the case of polypropylene.

The moistened yarn wound upon cores is then subjected to a vacuum of at least 20, but preferably over 27 inches of mercury. Then the space surrounding the package of yarn is filled with vapors of the acid anhydride, which upon combination with the water upon the yarn forms the acidic reagent which activates the yarn. If the acid anhydride is a material which boils below the treatment temperature, it may be introduced into the chamber where the treatment is being performed as a liquid and, by raising the temperature above the boiling point, be permitted to boil so that the vapor fills the space. More conveniently, the acid anhydride is admitted as a gas. As the acid anhydride reacts with the water upon the yarn, the pressure in the chamber in which the activation is being performed drops. Additional acid anhydride is introduced either incrementally or continuously to reestablish the desired pressure by means of a pressure sensitive valve or by manual control. The achievement of equilibrium is signified by cessation of the tendency of the pressure in the chamber to fall, i.e. by the maintenance of constant pressure in 'the chamber without the further addition of acid anhydride.

When equilibrium is reached it may be convenient to reapply vacuum to the chamber in order to remove the unreacted acid anhydride before opening the chamber.

The length of time required to achieve equilibrium depends upon the amount of yarn wound upon the packages, the winding pattern and the tightness of the winding, the identity and reactivity of the acid anhydride, the yarn size and extent to which it is bulked, and upon the temperature.

The process of this invention is particularly suitable for activating multi-filament yarns which have been texturized.

The higher the temperature of the activation process, the more rapidly equilibrium can be reached. However, the upper practical limit of temperature for thi process is that temperature above which the yarns which are to be activated by this process undergo excessive shrinkage, 140 C. in the case of polypropylene.

Acid anhydrides suitable for use in this invention are sulfur dioxide, sulfur trioxide, nitrogen dioxide, nitrogen pentoxide, and any other material which, upon combination with water, forms a Bronsted acid. (Bronsted acids are compounds capable of donating a proton in a reaction.) The preferred acid anhydrides for use in the process of this invention are sulfur dioxide and nitrogen dioxide.

No particular design for the chamber in which the process of this invention is to be performed is required. The chamber should be capable of withstanding a vacuum and should not be corroded by the materials employed in the process, notably the acid formed by the acid anhydride. It may be convenient to use an autoclave with a removable head to facilitate the loading and unloading of the packages of yarn to be treated. It is also convenient for the chamber to be fitted with a pressure gauge, to permit observation of the progress of the treatment and the achievement of equilibrium.

The yarns which may conveniently be activated by the process of this invention are those disclosed in the said co-pending applications.

The term hydrocarbon polymer is used herein to refer to the matrix material of which the fiber is largely composed. The preferred material in our invention is polypropylene, and further discussion will be mainly in terms of this representative hydrocarbon polymer for the sake of simplicity of expression. However, the invention is equally applicable to all fiber-forming hydrocarbon linear high polymers, including poly-(l-alkenes) such as polyethylene, poly-l-butene, poly(4-methyl-1-pentene), copolymers of two or more l-alkenes, copolymers of nonterminal olefins with l-alkenes, etc.

Examples of the highly polar basic polymers which we incorporate in the hydrocarbon polymers are basic nitrogen-containing materials of the following types.

(1 Thermoplastic polymers of vinyl-substituted monoand polycyclic pyridine bases, either homopolymers or copolymers, including graft copolymers.

(2) Thermoplastic polyamides, including condensation homopolymers and copolymers, in which the amide groups are an integral part of the polymer chain, and addition homopolymers and copolymers having pendant groups containing or consisting of amide groups.

(3) Amine polymers, including condensation homopolymers and copolymers, in which the amine group is an integral part of the polymer chain, and addition homopolymers and copolymers having pendant groups which include or consist of amine groups.

Other basic nitrogen polymers Which may be used are polyurethanes, polyureas, poly(vinylcarbazoles), anilineformaldehyde resins, etc.

The basic nitrogen polymers employed are not extractable from admixtures thereof with the hydrocarbon polymer, under the conditions of treating and dyeing used. Thus, after a one-hour extraction of the fiber with boiling water at a pH of 3, at least of the originally added nitrogen polymer should remain in the hydrocarbon polymer. The amount of the basic nitrogen polymer a ded o the hyd oca bo p ymer h ld be uf c e so that, after the treatment of the invention, it will bind the amount of dye required to produce the shade desired. IThe vinyl-substituted monocyclic and polycyclic pyridine base dye-receptor polymer incorporated in the hydrocarbon polymer in accordance with the invention is present either as a homopolymer, or as a copolymer with another vinyl monomer copolymerizable therewith, or as a graft copolymer with a hydrocarbon high polymer. The vinyl-substituted monoand polycyclic pyridine base dyereceptor polymers used as those based, for example, on monovinylpyridines and monovinylquinolines.

The monovinylpyridines useful in making the above named dye-receptive polymers include 2-vinylpyridine, 3- vinylpyridine, 4-vinylpyridine, 5-methyl-2-vinylpyridine, 2-ethyl 5 vinylpyridine, Z-methyl-S-vinylpyridine, 2- ethyl-6-vinylpyridine, 2-isopropenylpyridine, etc. Polymerizable olefinic monomers with which the monovinylpyridine may be copolymerized include acrylic and methacrylic esters typified by ethyl acrylate and methyl methacrylate, vinyl aryl hydrocarbons typified by styrene and vinyltoluenes, and butadiene-l, 3. Alternatively, the monovinylpyridine may be graft-copolymerized by well known methods with a previously formed linear high polymer, typified by polyethylene, polypropylene, polystyrene, and polybutadiene. It is always desirable that the basic polymer contain no more than a minor proportion of material copolymerized with a monovinylpyridine, since only the pyridine portion of the polymer additive is active in enhancing the dyeability of the hydrocarbon polymer.

The polyamides useful as the dye-receptors include homopolyamides such as poly(hexamethylene adipamide), poly(hexamethylene sebacamide), polyvinylpyrrolidinone polycaprolactam, polyenantholactam, and copolyamides such as Zytel 61 (Du Pont), an interpolymer of hexamethylene adipamide and hexamethylene sebacamide with caprolactam.

As examples of vinyl polymers with pendant groups consisting of or containing amide groups there are the substituted poly(vinylpyrrolidinones), e.g., N-vinyl-3- alkylpyrrolidinone, and N-substituted polyacrylamides, e.g., N-butylacrylamide. Also usable are copolymers of the amide-containing vinyl monomers with other olefinic monomers such as acrylic and methacrylic esters typified by ethyl acrylate and methyl methacrylate, vinyl aryl hydrocarbons typified by styrene and vinyltoluenes, and butadine-1,3. Alternatively, the vinylpyrrolidinones or acrylamides may be graft-copolymerized by well-known methods with a previously formed linear high polymer, typified by polyethylene, polypropylene, polystyrene, and polybutadiene. It is always desirable that the basic polymer contain no more than a minor proportion of material copolymerized with the vinylpyrrolidinones or acrylamides, since only the amide portion of the polymer additive is active in enhancing the dyeability of the hydrocarbon polymer.

As examples of amine polymers useful as the dye receptor, there are the condensation products of epihalohydrins or dihaloparaffins with one or more amines, such as those disclosed in Belgian Patent No. 606,306, exemplified by the condensation product of dodecylamine, piperazine and epichlorohydrin; as examples of addition polymers with pendant groups consisting of or containing amines there are the reaction product of a styrene-maleic anhydride copolymer with 3-(dimethylamino)propylamine (the reaction product being a polyamino-polyimide), and styrene-allylamine copolymers such as those disclosed in US. Patent 2,456,428.

The following examples will serve to further illustrate this invention.

EXAMPLE 1 A 375 filament, 3700 denier yarn melt-spun from a polymeric composition comprising 97% isotatic polypropylene and 3% of a copolymer of equal parts of 2-. vinylpyridine and 2-m y -5-vi y pyridine was t x urizerl and wound by a standard constant tension winding apparatus upon an ordinary cardboard cylindrical core to form a two pound package. As the yarn was being wound, it Was placed in contact with a roll wetted with an aqueous solution of a yarn finish. The yarn package, which contained 5% O.W.F. moisture, was placed in an autoclave. The autoclave was evacuated to 27 inches of mercury, and then sulfur dioxide was admitted until the pressure was again raised to one atmosphere. When the source of sulfur dioxide was shut off, the pressure in the autoclave gradually decreased. Additional increment of sulfur dioxide were introduced into the autoclave to keep raising the pressure back to atmospheric. After approximately 10 minutes at room temperature, no further incremental additions of S0 were required to maintain the pressure at atmospheric. The autoclave was again evacuated to remove unreacted sulfur dioxide and then opened to remove the yarn package. The yarn thus treated was subsequently found to be suitable for dyeing in uniform fashion by exposure to acid type dyes.

EXAMPLE 2 A 208 denier, 8 filament yarn melt-spun from a polymeric composition comprising 97% isotactic polypropylene and 3% Zytel 61, wound upon a cylindrical cardboard core to form a two pound package, was placed in an autoclave. The autoclave was evacuated to 27 inches of mercury. Steam was introduced to raise the total pressure in the autoclave to 23 inches of mercury. N0 was admitted to the autoclave to raise the pressure to atmospheric. Further increments of N0 were added to maintain the pressure at atmospheric. After approximately 10 minutes, no further additions of N0 were required to maintain the puressure at atmospheric. The autoclave was evacuated, and then opened to remove the yarn. The yarn, after washing, was uniformly dyed to a deep shade of orange with Capracyl Orange R (0.1. No. Acid Orange 178). Another sample of the same yarn was uniformly dyed blue with Dimacide Light Blue JL Acid Blue 25 (Cl. No. 62055).

Having thus described our invention, that we claim and desire to protect by Letters Patent is:

1. The process of uniformly exposing a yarn compris ing from 90 to 99.5% of a high polymer selected from the class consisting of polyolefins or polyesters and correspondingly from 10 to 0.5% of a highly polar basic nitrogenous polymer to an acid treatment to render said yarn dyeable with acid type dyes comprising: winding said yarn upon a core, placing said yarn-bearing core into a chamber, evacuating said chamber, introducing sufficient steam into said chamber to uniformly moisten said yarn with at least 1% (on the Weight of fiber) water, then raising the pressure in said chamber to substantially atmospheric pressure by the subsequent introduction thereinto of a gas selected from the class consisting of sulfur dioxide and nitrogen dioxide, and maintaining said pressure in said chamber at substantially atmospheric pressure by further introduction of said gas until equilibrium between said gas and said water is substantially established.

2. The process as defined in claim 1 in which the high polymer is a polyolefin.

3. The process as defined in claim 1 in which the high polymer is a polyester.

4. The process as defined in claim 1 in which the high polymer is polypropylene and the highly polar basic nitrogenous polymer is a homopolymer vinylpyridine. or copolymer of vinylpyridine with another vinylpyridine or vinyl monomer copolymerizable therewith.

References Cited UNITED STATES PATENTS 3,361,843 1/1968 Miller et al 260857 GEORGE F. LESMES, Primary Examiner D. LEVY, Assistant Examiner US. Cl. X.R. 8--31, 55, 100, 149.2, 155.2