United States Patent ()fifice 3,371,052 Patented Feb. 27, 1968 ABSTRACT OF THE DISCLOSURE A composition of matter for rendering a synthetic textile fiber static free and undiscolored being comprised of a polyepoxide, a polyamine, and a reducing agent which is applied to the fiber in the form of an aqueous emulsion.
Synthetic fibers when coming into contact with foreign objects tend to collect static electrical charges thereon which is objectionable during the manufacture and wearing thereof. The accumulation of static charges thereon prevents the finished synthetic fibers from draping like cotton or wool and causes the same to cling uncomfortably to the wearer. The static charges also attract dust and lint to the fabric. It is well known in the art that polyamines are effective temporary antistatic agents and when associated with the fibers which comprise a fabric in the presence of a polyepoxide, the polyamine molecules polymerize thereon and become durably attached thereto.
The methods and compositions are clearly shown in US. Patent No. 3,021,232 to Pretka and US. Patent No. 2,982,- 751 to Anthes, respectively. However, it has been found that when a fiber is treated with a polyamine compound, a discoloration results which is undesirable and which lowers the commercial value of the fiber. An aftcrwash may be applied but this is only partially effective for it does not remove all the discoloration. It also is an additional operation which is objected to as being time and money consuming. It is to this problem that attention of this application will be directed.
Therefore, an object of this invention is to provide a novel process which will impart to a synthetic textile fabric antistatic properties without discoloring the same.
Another object of this invention is to provide a novel composition of matter Which renders antistatic protection to a synthetic textile fabric without'discoloring the same.
A further object of this invention is to provide synthetic fibers which retain their original color after being associated with an antistatic agent.
These and other objects will become apparent in the course of the following specifications and claims.
In accordance with a preferred embodiment of the present invention, a synthetic textile fiber is provided with durable antistatic properties by continuously associating the fiber, either during the spinning thereof or when the fiber is in fabric form, with an aqueous polyamine/ epoxy resin compound which also contains a third ingredient. This third additive prevents the discoloration of the fiber by acting as a reducing agent.
The use of these antistatic agents, in accordance with the present invention, effects improvements in the characteristics of acrylonitrile polymers and articles produced therefrom. This invention is applicable not only to polyacrylonitrile, but also to copolymers, interpolymers and blends thereof, particularly those containing at least 80 -When the moisture content percent by weight of polymerized or copolymerized acrylonitrile. Such polymeric materials include acrylonitrile fiber-forming polymers with readily dyeable basic copolymers, the blend having an overall polymerized acrylonitrile content of at least percent by weight.
An acrylic fiber may be formed by extruding a typical acrylonitrile-based spinning dope through a conventional spinnerette into an aqueous coagulation bath wherein the dope hardens into a filament. After the fibers were washed and stretched as they were drawn up a hot water cascade, they are heated and partially dried on a set of drying rolls. of the fiber was approximately 20 percent by weight and the temperature of the filaments had reached approximately C., they were immersed in an aqueous emulsion which contains (a) a polyamine,
(b) an epoxide resin,
(c) a reducing agent, and (d) a lubricant Where the aqueous emulsion is appled to a fabric by padding, or the like, the lubricant may be eliminated for there is no problem of the fibers wrapping around the drying rolls. The mixture preferably contains a dispersing or emulsifying agent which insures a more homogeneous suspension of the several ingredients. The temperaures of the suspension is generally held at below 40 C. in order to prevent premature polymerization.
Also, this invention may be used in combination with polyester fibers. A fiber was formed by extruding a typical polyester melt, such as polyethylene terephthalate; through a conventional spinnerette downwardly through a chimney where the melt was air quenched and was hardened into filaments. The fibers were converged and collected on a bobbin as undrawn yarn. A number of bobbins were then combined and a tow was formed by continuously pulling the yarn therefrom. The tow was heated to at least 40 C. by being passed under a hot waterspray. The fibrous tow then passed into a draw zone Where the temperature thereof was increased to 80 C.90 C. by another hot water spray or by a finishing solution and was elongated from four to five times its original length. After the tow has been drawn, it is immersed in, padded, or sprayed with an aqueous antistatic emulsion which becomes polymerized thereon when heated to about C. The dried fibrous tow was then cut to staple lengths and processed according to conventional techniques.
The use of polyamine compounds as antistatic agents is controlled by the pH value of the mixture, however, the pH value is not necessarily a limiting factor. The effec tiveness is strictly dependent on the pH value for above seven, the effectiveness is much greater than below seven, although the lower the pH the less the color of the fiber is affected. Where the mixture is given a high pH value the fiber becomes discolored upon association therewith. It has been found that a pH of above seven is needed to functionally justify the use of the polyamine as an antistat; therefore, to inhibit discoloration, a reducing agent is used. The reducing agent functions to destroy the discoloration which is a characteristic by-product upon treating synthetic fibers with polyamines. Almost any reducing agent may be used; however, it has been found that the most effective ones are sodium bisulfite, sodium hydrosulfite, sodium sulfoxylate, formaldehyde, and oxalic acid. Oxalic acid may be used for adjusting the pH of the emulsion as well as for preventing the discoloration of the treated fiber.
An example of a polyamine in accordance with the present invention is a polyamine having the formula:
i it? it a tma m?- HH HHH HH and a mixture of these radicals wherein R is a lower alkyl radical, -E- is a divalent radical selected from the group of desoxy A radicals (i.e., an -A radical without its oxygen atom), m is a whole number from about 5 to 85 and n is a whole number from about 1 to about 50. The preparation of these polyarnines is discussed in Belgian Patent No. 554,506, granted Jan. 25, 1957. Such materials may be purchased on the open market from Onyx Chemical Company, 190 Warren Street, Jersey City, N.J., under the trademark Aston.
The epoxide resin referred to above can be prepared by condensing epichlorohydrin with a polyol. A typical example is the condensation product (with elimination of HCl) of glycerine and epichlorophydrin. The preparation thereof is described in detail in British Patent No. 780,288, dated July 31, 1957. Such a material is available on the open market under the trademark Eponite 100.
When an aqueous bath is prepared from water, a polyamine, an epoxy resin, and a reducing agent, it is desirable to add thereto a dispersing agent to insure a thorough dispersion of the insoluble Eponite 100. Satisfactory dispersing of emulsifying agents are the aromatic polyglycol ethers, one example of such being the alkylphenol olyglycol ether containing 9.5 moles of ethylene oxide which can be purchased on the open market under the trade- "mark Neutronyx 600.
The effectiveness of the reducing agents in reducing discoloration was checked in the manner as set forth below. Where the antistatic emulsion was applied to a tow, the finished filaments are converted into yarn and the yarn is knitted into a tubular fabric shape whereupon the fabric is blank dyed by any conventional dyeing process. Where the antistatic emulsion was applied to a finished fabric, it was also blank dyed by a conventional dyeing process. Hereinafter, the testing processes are the same for both types of samples. The fabric is washed in a Kenmore washing machine at 100 F. using 0.5 percent Tide detergent for four minutes or alternatively, a 0.3 percent solution of tetra sodium pyrophosphate may be used as the detergent. After the tube is removed from the Washing machine, it is centrifuged to remove the excess moisture. The steps of washing the tube in the detergent for four minutes, centrifuging it and drying it in an air atmosphere with a relative humidity of 35 percent at a temperature of 72 F. are repeated a selected number of times, whereupon the fabric is run on a Hayeck and Chromey apparatus to determine the level of static protection after selected washings. To determine purity (the effectiveness of the reducing agent in preventing discoloration), the fabric is tested by a General Electric spectrophotometer. Such test results are then compared with the results obtained on tubes treated with antistaic formulaions which do not contain a reducing agent.
The following examples are cited to illustrate the invention. They are not intended to limit this invention in any way. Unless otherwise noted, parts as expressed in the examples indicate parts by volume.
Example I A sample of acrylic fibers consisting of a copolymer of 93 percent acrylonitrile and 7 percent vinyl acetate in the form of a tow or fabric were treated by padding, drying,
curing and the like, with an aqueous emulsion having the following constituents:
Percent Polyarnine 15.00 Polyepoxide 1.50 Polyglycol ether 0.38 Zinc sulfoxylate formaldehyde 2.00
Water 81.12
The above identified emulsion was also applied to a polyester fiber sample. The total finish solids constituted at least 0.4 percent of the weight of the fiber. The pH of the above aqueous emulsion was adjusted to between 7 and 8 by hydrochloric acid. Several tests were run wherein the total finish applied to the fiber was varied over a wide range by changing the relative concentrations of the finish ingredients which comprise the aqueous emulsion. Table I (immediately below) shows the elfect the reducing agent had on purity, purity being determined by the General Electric spectrophotometer.
TABLE I Sample Treatment Purity Acrylonitrile based fabric- Emulsiton without reducing 9. 2
agen Do Emulsion with zinc sulfoxylate 5.1
formaldehyde. Polyester fabric Emulsion without reducing 9. 3
agen Do Emulsion with zinc sulfoxylate 5. 3
formaldehyde.
Example 11 The finish solutions applied to acrylonitrile based fibers and polyester fibers as described in Example I were modified by substituting 2 percent sodium sulfoxylate formaldehyde for zinc sulfoxylate formaldehyde. The remainder of the elements were added in the proportions of Example I. The samples herein disclosed were evaluated according to the procedure of Example I and yielded the results illustrated in Table II.
TABLE 11 Sample Treatment Purity Acrylonitrile based fabric. Emulsion without reducing 9. 2
ngon Do Emulsion with sodium sultoxyl- 5. 3
ate formaldehyde. Emulsion without reducing 9. 4
agent. Emulsion with sodium sulfoxyl- 5. 1
ate formaldehyde.
Example III The finish solutions applied to acrylonitriie based fibers and polyester fibers as described in Example I were modified by substituting sodium hydrosulfite for zinc sulfoxylate formaldehyde. The samples herein disclosed were evaluated according to the procedure of Example I and were treated with an aqueous emulsion which was com prised of the following constituents:
Percent Polyamine 10.00 Polyepoxide 1.00 Polyglycol ether 0.25 Sodium hydrosulfite 0.50
Water 88.25
Table III illustrates the effectiveness that the reducing agent had on purity.
TABLE III Sample Treatment Purity Acrylonitrile based fabric. Emulsion without reducing 9. 2 Do n iiiiiin with sodium hydro- 6.7 Polyester fabric Er ri lii sio n without reducing 9. 3 Do Er ii jl si on with sodium hydro- 0. 8
sulfite.
Example IV The finish solutions applied to the acrylonitrile based fibers and polyester fibers as described in Example I were modified by substituting 2.0 percent formaldehyde which is in a 40 percent solution for the zinc sulfoxyla-te formaldehyde; the proportions of the remaining elements were left unchanged. The samples herein disclosed were evaluated according to the procedure of Example I and yielded the results illustrated in Table IV.
As previously described, a synthetic textile filament in the form of a tow or fabric is treated with an aqueous emulsion comprising the mixture of a polyepoxide, a polyamine and a reducing agent. The concentration of the reactants in the suspension may vary widely, however, emulsions containing from about 1 percent to about 30 percent by volume of reactants are generally preferred. Such an emulsion will be able to provide a synthetic fiber with an adequate amount of antistatic protection without having the undesirable discoloration which is generally present when a synthetic fiber is associated with a polyamine. After the fiber has been associated with the antistatic aqueous emulsion, the reactants are cured thereon by raising the temperature thereof to 145 C. for six minutes.
Many different modifications of the invention may be made without departing from the scope and spirit thereof. It is contemplated that variations may be made in the percentages of the compounds used without greatly altering the antistatic characteristics of the fiber; therefore, the applicant does not wish to be bound by the numbers exactly as they appear herein.
I claim:
1. A composition of matter for rendering synthetic fiber static free and undiscolored, said composition comprising:
(a) a polyepoxide obtained as a condensation product of epichlorohydrin and a polyol,
(b) a polyamine having the formula H(D--A -E),,DH where D is a divalent radical terminating in amino nitrogen, --A is a divalent radical selected from the group consisting of 3. A composition of matter according to claim 1 wherein the reducing agent is sodium sulfoxylate formaldehyde.
4. A composition of matter according to claim 1 wherein the reducing agent is sodium hydrosulfite.
5. A composition of matter according to claim 1 wherein the reducing agent is formaldehyde.
6. A composition of matter according to claim 1 wherein the reducing agent is oxalic acid.
7. A process of rendering an undiscolored, static free fiber comprising the steps of applying to the fiber a mixture in the form of an aqueous emulsion of (a) a polyepoxide obtained as a condensation product of epichlorohydrin and a polyol,
(b) a polyamine having the formula amino nitrogen, A- is a divalent radical selected from the group consisting of and a mixture of these radicals wherein R is a lower alkyl radical, E is a divalent radical selected from the group of desoxy A- radicals, in is a whole number from about 5 to '85 and n is a whole number from about 1 to about 50, and
(c) a reducing agent selected from the group consisting of oxalic acid, zinc sulfoxylate formaldehyde, sodium sulfoxylate formaldehyde, sodium hydrosulfite, and formaldehyde, and polymerizing said mixture on said fiber.
8. A process according to claim 7 wherein the reducing agent is zinc sulfoxylate formaldehyde.
9. A process according to claim 7 wherein the reducing agent is sodium sulfoxylate formaldehyde.
10. A process according to claim 7 wherein the reducing agent is sodium hydrosulfite.
11. A process according to claim 7 wherein the reducing agent is formaldehyde.
12. A process according to claim 7 wherein the reducing agent is oxalic acid.
13. A process according to claim 7 wherein the textile fiber is comprised of synthetic fibers which are chosen from the group consisting of polymerized acrylonitrile and a copolymerized mixture of acrylonitrile and up to about 15 percent by weight of at least one monomer copolymerizable therewith.
14. A process according to claim 7 wherein the textile fiber is formed from a polyester.
15. A process according to claim 7 wherein the said synthetic textile fiber is in fabric form.
16. A process according to claim 7 wherein the mixture is at a pH of above 7.0.
References Cited UNITED STATES PATENTS 2,5 00,449 3/ 1950 Bradley 260 -2 2,878,214 3/1959 Holmes et a1. 26045.7 2,878,221 3/1959 Jenkins et a1. 260--45.7 2,965,517 12/ 1960 Albrecht et a1. 260-2 WILLIAM H. SHORT, Primary Examiner. T. PERTILLA, Assistant Examiner.