BACKGROUND OF THE INVENTION

This invention relates to the process for improving the run and snag resistance of hosiery knitted from synthetic fibers and to a synthetic resin composition useful for rendering knitted fabric, e.g., nylon hosiery, resistant to runs or snags. Heretofore, to render stockings resistant to runs, it was necessary to utilize an adhesive-type material which would form visible patterns and be seen as a blemish on the hosiery. Moreover, adhesives were applied by spraying the material, which formed a coating on the fabric which would reduce the elasticity to a fraction of what it was prior to the spray treatment. The disadvantage of treating knitted fabric, e.g., nylon hosiery, to render the hose resistant to runs by the use of adhesives is avoided by the present invention. More specifically, this invention is directed to machine-made knitted fabrics, including knitted articles such as ladies' hosiery and the like. This invention is particu- larly concerned with fabric knitted from continuous fila- ments, including natural materials such as silk, or artifi- cial filaments such as nylon and rayon. The term "filament" denotes an elongated knittable or continuous structure, as distinguished from spun yarn. The continuous filaments are characterized by having a uniform cross section and a smooth surface. However, one of the problems with filamentary knitted materials of fine gauge is that the stitch is suscep- tible to laddering. For example, in ladies' hosiery, a loop

stitch broken at the knee may cause a ladder along the length of the stocking. When hosiery are worn, they are susceptible to a certain amount of lateral tension which tends to weaken the loop stitches and thereby disengage successive stitches once a broken stitch occurs. The treatment of fine gauge knitted materials in accordance with this invention involves forming a film on the hosiery to prevent laddering and also to maintain a sufficient degree of elasticity to ensure a good fit without permanent distortion. In accordance with this invention, fine or sheer knit goods are treated with a solution comprising a polymeric resin of various concentrations, depending on the means by which the solution of resin is applied to the fabric. For purposes of this invention, the polymeric resin is applied to the fabric in effective amounts sufficient to resist runs or snags, i.e., amounts ranging up to about 3% by weight of the fabric.

DETAILED DESCRIPTION OF THE INVENTION

The resins useful in preparing the hosiery treat- ment compositions of this invention are film-forming resins which, when applied to the hosiery, improve the run and snag resistance of the knitted fabric. The film-forming resins can be sprayed onto the hosiery by utilizing various types of dispensers. Most of the resin dispensers are aerosol con- tainers from which the resin is discharged by a propellant. More recently, because of environmental requirements, the pump spray applicators, i.e., utilizing a mechanical pump, discharge the resin forming a protective film on the fabric. The resin composition of this invention comprises solutions of the polymeric resin in combination with amines, alcohol amides, solvents and water. More specifically, this invention relates to a process for improving the tear resistance, i.e., the run and snag resistance, of hosiery knitted from synthetic fibers which comprises treating the hosiery with small but effective amounts, e.g., up to about 3% by weight of the fabric with a synthetic resin composition consisting essentially of (a) from about 0.5 to 15 parts by weight, preferably from about 1.0 to 10 parts by weight, of a polymer- ic synthetic resin having an average molecular weight ranging up to about 100,000, and preferably an average molecular weight ranging from about 20,000 to 60,000, (b) from about 0 to 2.0 parts by weight of at least one aliphatic amine neutralizing agent, and prefer- ably froήTabout 0.03 to 0.1 part by weight of the amine neutralizing agent, (c) from about 70 to 99 parts by weight of at least one organic solvent, e.g., lower alcohols for said

synthetic resin, and preferably from about 75 to 90 parts by weight of said organic solvent, (d) from about 0 to 15 parts by weight of water, and preferably from about 2.0 to 10 parts by weight of water, (e) from about 0 to 1.0 part by weight of a cosmetic adjuvant, (f) from about 0.01 to 3.0, e.g., 0.01 to 0.3, parts by weight of an alcohol amide, and (g) from about 0 to 90 parts by weight, and preferably from about 25 to 50 parts by weight, of a propel- lant.

Where the resin composition is used in a container in combination with a propellant, the preferred propellants include the halogenated hydrocarbons, e.g., trichlorofluoro- methane, dichlorodifluoromethane, and the like. Other useful propellants can be found on page 443 of Volume 2 of Cosmet- ics, Science and Technology, and in U.S. patents Nos. 3,026,- 250 and 3,145,147. Examples of compressed gas propellants include nitrogen and carbon dioxide. These propellants are used preferably in amounts ranging from about 10 to 75 parts by weight, and more likely in amounts ranging from about 25 to 50 parts by weight of the total composition. In addition, there are spray pump applicators for dispensing the synthet- ic resins. These are disclosed in the publication Soap, Perfume and Cosmetics, March 1977, pp. 89-93. There are also various mechanical pump devices described in Modern Packaging for October 1975, pp. 15 through 20. The present invention also provides spray composi- tions which utilize aliphatic hydrocarbons as the propellant, e.g., propane or butane, etc., and combinations thereof, with up to 50 parts by weight of water. Water helps to reduce the flam ability of the hydrocarbon propellants.

The preferred resin composition comprises copoly- mers of vinylalkyl ethers and a monoethyl or monobutyl ester of maleic acid or its anhydride, and from about 0.1 to 0.5 part by weight of an amine neutralizer for the free carboxyl groups of the copolymers.

Specifically, the copolymer of a monoalkyl ester of maleic acid and a vinylalkyl ether can be characterized by the formula:

wherein R is an aliphatic radical having from 1 to 4 carbon atoms, R^ is either an ethyl or butyl group, and x has the value sufficient to obtain polymers having average molecular weights ranging up to 100,000, e.g. , from 20,000 to 60,000. The preferred comono ers, i.e., vinylalkyl ethers, for purposes of this invention include methylvinyl ether ^" and butylvinyl ether. These resins are prepared by conventional polymerization methods as set forth in German patent No. 571,665. These particular resins have average molecular weights ranging from about 20,000 to 60,000, with viscosities ranging from about 1.5 to 6 centipoise, i.e., a 5% solution in dimethyl formamide at 34 C. Commercially available resins include the copolymers of monoethyl ester of maleic acid and methylvinyl ether (Gantrez ES-225) and the copoly- mers of butyl monoester of maleic acid and vinylalkyl ether, commercially available as Gantrez ES-425. Where the polymeric resins contain free carboxyl groups, the copolymer may be completely or partially neutral- ized by the addition of from about 0 to 2.0 parts by weight of a basic compound including amines such as dimethylamine ,

diethylamine, triethanolamine, 2-methyl-2 amino-1-propanol , etc. The addition, for example, of from about 0.1 to 0.5 part by weight of an amine neutralizing agent represents up to about 30% neutralization of the unreacted free carboxyl groups of the copolymer. These copolymers may be completely or partially neutralized with the amine to the degree of from about 10 to 75% of the free or unreacted carboxyl groups on the polymer. Other synthetic resins useful for purposes of this invention include the polyvinylpyrrolidones and the copoly- mers of vinyl acetate and crotonic acid, as particularly disclosed in U.S. patent No. 2,996,471. Specific resins include terpolymers derived from vinyl acetate crotonic acid and a vinyl ester of aliphatic monocarboxylic acid having a minimum of 5 carbon atoms in the carboxyl moiety. These particular terpolymers are disclosed in U.S. patent No. 3,810,977, and are commercially available under the trade name "Resyn" terpolymer. Of the various polymeric resins, the copolymers of methylvinyl ether and maleic anhydride in a ratio of about 1:1 are particularly preferred. These copolymers are esteri- fied with aliphatic alcohols having 1 to 4 carbon atoms, and are neutralized, i.e., via acid groups, by using neutralizing agents such as the amines, and particularly the amino alco- hols such as 2-amino, 2-methyl 1,3 propanediol and 2-amino, 2-methyl-l-propanol, etc. These and other neutralizing agents are known in the art, as set forth in U.S. patent No. 2,996,471. Other useful terpolymers for purposes of this invention includes the polymers of vinyl acetate, crotonic acid, and a vinyl versatate. Similar copolymers include copolymers of vinylpyrrolidone with vinyl acetate and various acrylic polymers including polymers derived from the acryl

amides, the acrylate, and the methacrylates which contain unreacted carboxyl groups. The acrylic synthetic resins can be derived from the copolymerization of various monomers, particularly the lower alkyl acrylate and/or methacrylates, and especially the methyl, ethyl, propyl, isopropyl, hexyl or octylacrylates or methacrylates. The preferred copolymers comprise reoccuring units derived from acrylic or methacrylic acid or units derived from the lower alkylacrylates or methacrylates and allyl alcohols. These acrylic copolymers can be neutralized, e.g., up to 100%, with effective amounts of amine compounds such as the ethanolamines, propanolamines and various other amino alcohols, such as 2-amino, 2-methyl 1,3 propanediol, etc. The liquid carriers or organic solvents used for the synthetic resins preferably include the lower molecular weight alcohols, such as ethanol, propanol, isopropanol, butanol, the alkoxy alcohols, and combinations thereof, alone or with water. In addition to the synthetic polymeric resins, the amines, the solvents and propellant, the resin compositions of this invention may comprise small but effective amounts, e.g., up to 1 part by weight, of one or more ingredients known in the cosmetic art, including, for example, perfumes, conditioning agents, plasticizers, or the like. In order to reduce the foaming characteristics of the resin composition and improve the solubility of the resin to prevent severe accumulation of the resin at the nozzle of an aerosol or pump dispenser, it was found necessary to incorporate in the composition from about 0.01 to 3.0 parts by weight of an alcohol amide compound, i.e., 2,4 dihydroxy- N-(3-hydroxypropyl) 3,3-dimethyl butyramide. While the alcohol amide is not critical to the composition for improv- ing the tear resistance of hosiery, it is essential for use

in aerosol and pump spray equipment to prevent severe accumu- lations and improve solubility of the resin at the nozzle. This particular alcohol amide was found to be unique in combination with the resins derived from copolymers of vinylalkyl ethers and the lower alkyl monoesters of maleic acid. The following examples are illustrations for treating fabrics prepared from synthetic fibers such as nylon and rayon to improve the tensile strength, and thereby resist runs and snags.

The resin is a 50% solution in alcohol of a copolymer of methyl¬ vinyl ether and maleic acid butyl ester avail¬ able as Gantrez.

Pantothenol is 2,4 dihydroxy-N-(3-hydroxy propyl)-3,3-dimethyl butyramide.

Components

Polymeric resin of Example 1

Pantothenol

.AMPD (amine base)

Solvent, e.g., alco

EXAMPLE 5

Components Parts by Weight

Polymeric resin of Example 1 5.34

Pantothenol 0.03

AMPD (amine base) 0.1

Solvents 94.5

EXAMPLE 9

Components Parts by Weight

Polymeric resin of Example 1 5.34

Pantothenol 0.3

AMPD (amine base) 0.1

Solvent 94.5

With an average of about 8 testers for each of the above Examples, hosiery treated in accordance with this invention showed that as the pantothenol (amide) and amine (.AMPD) base were varied with respect to one another, the optimum ratio between the AMPD and pantothenol as illustrated in Example 8 resulted in an increase in average days of wear of 6.67 as compared to the other Examples, which resulted in an average of about 4+ days of wear. While the pantothenol and amine base can vary, e.g., from 0.01 to 0.3 part by weight of pantothenol with respect to 0.03 to 0.1 part by weight of the amine, it was found that as the pantothenol in- creased the average days of wear increased. As illustrated by the Examples, the various components of the synthetic composition may be varied within the ranges stated with respect to one another without adversely affecting the use of the composition for the purpose set forth in this applica- tion. The relative amounts of each of the components of the composition were found not to be as effective when the amine neutralizing agent was reduced to a ratio below 0.03 part by weight with respect to the pantothenol. Similarly, it was found that the most effective composition was obtained when utilizing pantothenol in an amount ranging from about 0.01 to 0.3 part by weight for 0.03 to 0.1 part by weight of the amine base. Accordingly, while the ratios between the panto- thenol, AMPD, and the synthetic resin may vary within the ranges as set forth herein, their optimum ratios with respect to the amount of AMPD and pantothenol used in combination with the synthetic resin will depend on the particular composition of the resin utilized, as described herein. In accordance with this invention, the resin in combination with the amide and amine base used to treat the knitted fabrics imparts a greater coefficient of friction or slip resistance than is found in untreated fabrics, and this,

in turn, improves the tensile strength and resistance to tears, runs, snags, and the like. While this invention has been described with respect to a number of specific embodiments, it is obvious that other variations or modifications may be made without departing from the spirit and scope of the invention as set forth in the appended claims.