Method of conditioning fabrics and product therefor

Abstract

The requirement of critical introduction of softening or other modifying agents into a wash cycle for effective conditioning is obviated by a new method of conditioning which utilizes an article on which the conditioning agent is removably coated and from which the agent is transferred onto the clothes e.g. by cotumbling therewith in a dryer.

Parent Case Text

REFERENCE TO COPENDING APPLICATION

This application is a continuation of my application, Ser. No. 753,531 filed Aug. 19, 1968 and entitled "Method of Conditioning Fabrics and Product Therefor" now abandoned and which, in turn, is a continuation-in-part of application Ser. No. 479,590 filed Aug. 13, 1965 and now U.S. Pat. No. 3,442,692, issued May 6, 1969.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is concerned with surface modification of fabrics to impart desired properties thereto, primarily softness or "hand," but also including antistatic, lubricating, bacteriostatic, mildew and moth-proof properties. It is common practice in laundering to treat various types of household and garment fabrics, such as wool, cotton, dacron or nylon, with one or more specialized conditioning agents selected for example to render them soft to the touch and/or to reduce knotting or wrinkling; to facilitate ironing the fabrics, or to render the clothes free of static, or bacteria-resistant, or to deodorize or in any other way to condition them.

2. Prior Art

Fabric conditioning is presently done by introducing a liquid comprising a solution or dispersion of the agent into the washing machine either during the washing cycle or the rinsing cycle and particularly in the last rinsing step. Because most fabric conditioning agents are cationic and hence chemically incompatible with the soaps and anionic detergents in the wash water occluded in the fabric conditioning effectiveness is greatly reduced. Thus, there is no assurance that an effective amount of the agent will remain on the fabric when adding the liquid conditioning agent at the start of the last rinsing step, as there may be residual detergent or soap present, especially in the home laundry.

The criticality of agent addition timing means that the housewife must attend her supposedly automatic machine until the proper moment, which is a major inconvenience. Moreover, application of the agent from a liquid dispersion or solution is uneconomical because the relatively low solubility of most conditioning agents necessitates solution and dispersion in 16 to 20 times as much solvent, usually water or water-alcohol mixtures, as agent; this increases packaging, shipping and handling costs.

SUMMARY OF THE INVENTION

The present invention is designed to overcome difficulties now encountered in conditioning fabrics, especially in the home. Summarizing the invention, it comprises carrying the conditioning agent in solid form as a removable coating on a web substrate, which may be readily packaged, handled and shipped or transported and used, all in the dry state. In use, a sheet of the substrate carrying the agent may be placed in a conventional laundry dryer with washed, but still wet or damp fabric which may include sheets, garments, pillow cases, etc., rinsed of detergents or soaps. The fabric articles and conditioner are tumbled together and the coated conditioner is transferred to the fabric to place the conditioner on the same.

Specifically the invention provides a fabric conditioning method, a fabric conditioning article and a package suitable for conveniently retailing and using premeasured fabric conditioner quantities. With respect to the method, the invention provides, in the conditioning of fabrics by addition of conditioning agents thereto, the step of commingling the fabric to be conditioned and a substrate on which the conditioning agent is removably coated in a manner to effect transfer of the agent to the fabric and coated substrate and repeated random contact between substrate and fabric is typically used for transfer such as is readily effected in an ordinary clothes dryer filled with clothing which is initially damp and which is tumbled under drying conditions of elevated temperature forced air circulation. The conditioning agent is preferably a low melting normally solid material and may be carried on a substrate less sorptive than the fabric whereby contacting of the coated substrate with the fabric at temperatures above the softening temperature of the conditioning agent effectively transfers the agent to the fabric. A fabric conditioning article is provided including a carrier comprising a suitable tear-resistant web and a coating thereon of fabric conditioning agent which is removable to a fabric contacting the carrier. The web is of cellulose fiber such as ordinarily, a paper, and may be substantially nonadsorbent to better maintain the agent on the surface thereof. The conditioning agent or conditioner may be any fabric modifying material desirably placed on fabrics and is more usually a softening product such as an organic compound having both hydrophilic and hydrophobic character. Primary among these are the organic nitrogen containing compounds which are substantive to fabrics and which contain at least 12 carbon atoms, such as the fatty amines and their salts or quaternarized amines, particularly those having the Structure I or II depicted hereinafter in which at least one substituent group is hydrophobic i.e. contains 12 or more carbon atoms and in which the associated anion is a halide.

An important advantage of the present invention is the efficiency and ease of packaging, marketing and use of the just-mentioned articles. The conditioning agent may be applied to the substrate web as a 100% solids coating, and rolled or interleaved for wrapping and sale. Moreover, the web may comprise separate and separable sheets e.g. separable along longitudinally spaced transverse lines of weakness formed by perforation or scoring. The sheets are readily made of a size to delimit premeasured quantities of conditioning agent, related to area, whereby a portion only of the substrate web and appropriate to the fabric quantity to be treated may be selected and combined with the fabric in the dryer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevational view of a conventional form of apparatus which may be employed for effecting application of a fluid conditioning agent to a continuous web;

FIG. 2 is a schematic elevational view of a well known type of household laundry dryer; a portion of the structure being shown broken away; and

FIG. 3 is an isometric view of a perforated roll of the coated web from which individual sheets can be readily detached by the housewife for use in the method thereof.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Simply stated, the invention enables introduction of fabric softeners or other conditioners to fabrics at the most convenient and most effective time. Because the conditioners are used in the drying cycle rather than in the terminal part of the washing cycle, the housewife is free of need to watch her washing machine for the right moment. Because the conditioners, which may be detergent sensitive, are added only after substantially all detergent has been removed the deleterious effect of detergent on the conditioner is minimized.

The present articles are easily prepared by coating a conditioning agent onto a suitable substrate. Requirements of a good substrate are ability to retain the coated conditioner, resistance to shredding or other tearing failure when tumbled with damp clothes, absence of a tendency to ball up when wet or damp, and efficient transfer of coated conditioner. Suitable substrates will thus include materials having sufficient wet strength and surface area to carry adequate quantities of conditioner into the dryer or other commingling device. Porous or nonporous, woven or nonwoven, calendered or extruded sheet materials are highly useful. The conditioner on the substrate surface is most readily transferred to fabric and therefore substrates relatively impermeable to the conditioner such as moisture resistant fibrous materials including wet strength papers, regenerated cellulose, rayon, nylon, polyester, polyacrylonitrile, polyolefin and other synthetic woven or unwoven fibrous materials are preferred for economy in application of conditioner. Wet strength paper offers a good balance of performance and cost and is highly preferred. As used herein such paper is considered to be paper which has been impregnated with a waterproofing or sizing material such as a thermosetting resin e.g. a phenol- or amine-, especially melamine-formaldehyde resin or casein, starch or other impregnant, having the effect of reducing water absorption by fibrous cellulosic products. Additionally, waxy papers which carry coatings or impregnations of paraffin or a microcrystalline or synthetic wax may be used, e.g. "butcher paper" or dry waxed paper, to the extent of reducing moisture absorption but permitting adherent coating of the paper with conditioning agent.

In physical terms, the wet strength papers retain at least 15% of its dry strength and preferably 20 to 60% thereof when water saturated. The presence of sizing resins tends to stiffen the paper and inhibit balling up in a dryer, which thus affords additional surface area for transfer contact of the conditioning agent to the fabric. Kraft papers (20-40 lbs.) having a caliper of 15 to 65 mils and containing 3.5 to 8 pounds of thermosetting resin per ream have provided excellent results, particularly those remaining at least moderately flat in the dryer.

Onto the just described substrate material there is placed a coating of the conditioning agent. The agent may be impregnated in the carrier sheet to provide a relatively thin coating but best results in terms of conditioning agent and cost are realized when the substrate carries the agent substantially as a discrete surface coating. This coating may be of irregular thickness on the substrate, e.g. of 0.1 to 10.0 mils. A desirable amount of the coating is about 4 grams per ft..sup.2 on the surface of the substrate, one side or half the amount per side if both sides are coated.

It will be apparent that many materials might be added to fabrics following fabric washing e.g. a silicone to give ease of ironing, a bacteriocide-fungicide to combat mildew fungus and odor, or an antistat to prevent "cling" particularly in nylon fabrics. The most universal preference however, is for an improvement in the feel or hand of the fabric, i.e., downy softness instead of harshness resulting from hard water or detergent use. The present method and article are highly advantageous as a means of imparting softening conditioning to fabrics. Obviously the relationship of the various conditioning agents and the substrate is a physical one and for that reason any conditioning agent able to be adhered to the substrate, and transferred to the fabric may be used for its specific effect. The following illustrative materials are therefore not limitative of the scope of the invention.

Typically fabric softeners are cationic materials having substantivity to fabrics. Anionic and amphoteric materials are also useful however, depending on the fabric. In general, useful softeners are organic compounds which (1) contain primary, secondary, tertiary or quaternary nitrogen, or which are phosphonium or sulfonium compounds and (2) have a relatively long hydrocarbon group substituent conferring hydrophobicity and lubricity. Among such groups are alkyl groups containing 12 or more carbon atoms and desirably at least 16 to 18 up to 22 carbon atoms to effect efficacious softening. Other substituent groups on the nitrogen may be hydrocarbon, usually of fewer than 8 carbon atoms, on relative polar groups such as carboxyl, hydroxyl, alkoxy and ester groups of fewer than 8 carbon atoms. Typical fabric conditioners include:

A. Primary, secondary, and tertiary amines or diamines and their water soluble or water dispersible salts. For example:

R.sub.1 --NH.sub.2 ;

R.sub.1 --NH--R.sub.2 ; ##SPC1##

where R.sub.1 and/or R.sub.2 may each be an alkyl group of 12 to 22 carbon atoms; R.sub.3 and R.sub.4 are lower alkyl, e.g. methyl or ethyl groups; and where R.sub.5 is an alkylene chain of 4 or 6 carbon atoms wherein the two middle carbon atoms are linked to each other by an ether oxygen or by a double or triple bond. The following is a list of compounds of such type:

1. Partially substituted primary, secondary, or tertiary amines with various fatty constituents such as lauryl, palmityl, stearyl, coco, tallow or oleyl.

Examples:

hydrogenated tallow amine (RNH.sub.2)

dicoco amine (R.sub.2 NH)

Coco dimethyl amine (RN(CH.sub.3).sub.2

Trade names:

Armeen series (Armour);

Alamine series (General Mills);

Formonyte 600 series (Foremost).

2. Diamines with various fatty constitutents including coco, tallow, and oleyl. Common among the available diamines are N-alkyltrimethylene diamines (R--NH--C.sub.3 H.sub.6 --NH.sub.2)

Trade names:

Duomeen Series (Armour);

Formonyte 800 series (Foremost).

3. Ethoxylated amines and diamines with fatty alkyl groups of coco, tallow, soya, and stearyl, typically with 2, 5, 15 or 50 moles ethylene oxide: ##SPC2##

Trade names:

Sipenol series (Alcolac);

Ethomeen series (Armour);

Ethoduomeen series (Armour).

B. A quaternary or bis-quaternary ammonium base or salt. For example the following Structures I and II referred to previously: ##SPC3##

where X may be any of the following: OH, Cl, Br, CH.sub.3 OSO.sub.3, SO.sub.4, or similar anion, and R.sub.1, R.sub.2, R.sub.3, R.sub.4, and R.sub.5 the same as above. Salts of this type include:

Distearyl dimethyl ammonium chloride

N-alkyl trimethyl ammonium chloride

Dialkyl dimethyl ammonium chloride

Methyl difatty alkoxy ammonium sulfate

2,2'-bis(stearyldimethyl ammonio) diethylether dichloride

Alkyl groups include lauryl, cetyl, stearyl, coco, soya, and tallow

Trade names:

Arquad series (Armour);

Adogen series (Ashland);

Culversan series (Culver);

Varisoft 222 (Varney).

C. Alkyl imadazolines and imadazoles, including:

1-beta hydroxyethyl-2-alkyl imadazoline where the alkyl group is lauryl, oleyl, stearyl or tall oil ##SPC4##

2-alkyl-1,1-methyl [(2-alkylamido) ethyl]-imidazolinium methosulfate ##SPC5##

where:

R.sub.1 =c.sub.15.sub.-21

r.sub.2 =c.sub.16.sub.-22

trade names:

Onyxsan series (Onyx);

Monazoline series (Mona);

Armosoft AB (Armour).

D. Alkyl pyridine and piperidine salts, including:

Alkyl pyridinium chloride

Stearamidomethyl pyridinium chloride

Stearoxymethyl pyridinium chloride

Trade name:

Ammonyx CPC (Onyx).

E. Alkyl sulfonium salts,

An example of a salt of this type which has been prepared is: ##SPC6##

F. Alkyl phosphonium salts.

G. Esters of amino acids, such as: ##SPC7##

H. Esters of amino alcohols, such as: ##SPC8##

Fatty acid esters of ethanol amines, such as stearic acid ester of triethanolamine.

Stearic acid ester of dibutylamino ethanol

Trade name:

Soromine series (GAF).

I. Alkyl guanidine and their salts, in which the alkyl groups contain 8-18 carbon atoms, such as Guanidine stearate.

Effective as antistatic agents are usually the quaternary ammonium salts, e.g. chlorides, bromides, or sulfates, and the alkyl imidazolinium chlorides, bromides, or sulfates, e.g. alkyl dibenzyl ammonium chlorides and alkyl amines in which at least one alkyl group contains from 12 to 22 carbon atoms. Quaternary nitrogen compounds such as alkyl dimethyl benzylammonium and dodecyl trimethyl ammonium halides are also desirable bacteriostatic agents.

The amount of conditioning agent incorporated onto the substrate is that which is effective, without substantial excess which would serve no purpose. The actual amount in any given case is variable and will depend on the end use, the agent and the substrate employed. For example, about 1.0 to 10.0 grams of a softening agent on a sheet of approximately 105 square inches of paper, introduced will usually suffice for the normal household dryer in which the usual load of 5 to 10 lbs. of fabric is dried in about 40 to 60 minutes under normal drying conditions of about 120.degree.F. to 190.degree.F. In commercial laundries having greater dryer capacity, more agent carrying substrate sheets are added with the fabric pieces to the dryer.

Many of the aforementioned agents are normally solid and low melting as well as soluble or dispersible in water or in water-alcohol (desirably isopropyl alcohol for economy). To coat them onto a substrate, the substrate is dipped into a solution or dispersion of the agent having a concentration sufficient to provide the desired amount of agent on the substrate, or the substrate is coated with a hot melt or solution in a suitable liquid of the agent by any coating technique including a roll applicator which meters the coating onto the substrate, followed by chilling or if a solvent is used by the removal of the solvent from the substrate by drying either at ambient temperature or in an oven.

The resultant treated substrate can then be distributed in perforated roll form from which individual sheets can be readily detached, with each sheet carrying a desired predetermined amount of agent, or it can be packaged in the form of a stack of individual separated sheets each carrying such amount of agent.

The apparatus of FIG. 1 comprises a coating pan 6 containing a molten agent coating composition 7, and in which is rotatably mounted a conventional applicator coating roll 8 of metal, such as steel. A conventional doctor blade 9 is in slight frictional contact with the coating roll to smooth out the liquid which is applied to the underside of web 11 as it moves continuously with a smooth, uninterrupted motion in the general direction indicated by the arrows as the web is unwound from a supply roll (not shown). A conventional continuously rotatable back-up roll 12 having a resilient covering 13, desirably rubber, provides a nip with roll 8 between which continuously moving web 11 passes; the web being trained over conventional idler rolls 14 on either side of the nip.

After the underside of the web is coated, it is continuously conveyed to a rotatable chill roll 16 between additional idler rolls 14, and which may be water cooled whereby the melt is solidified to leave the conditioning agent as a solid coating on the surface of the web.

Upon leaving the chill roll the coated web is rewound into a roll 17. A coating of the conditioning agent may be applied to each side of the web or only one side by evident variations in the coating line.

The coated web 11 may be formed into roll 18 by conventional means, of the size usually employed in household rolls e.g. of paper toweling. As shown in FIG. 3, the roll 18 is formed of wound web 11 with spaced lines of weakness 19, in the form of perforations, detachably connecting sections 21 which provide sheets having a coating 22 of the agent, each sheet being of a size carrying the same predetermined amount of agent suitable for use in treating a usual load of clothes in a conventional household dryer.

Thus, the perforated roll provides a package whereby the conditioning agent is usable in predetermined increments merely by detaching the respective sheets 21 along their lines of weakness 19. Although a dispensing roll is preferred, predetermined sizes of the substrate carrying each the same premeasured amount of conditioning agent may be dispensed from conventional dispensing packages as individual sheets.

As is illustrated in FIG. 2 of the drawings, sheet 21 coated with a fabric conditioning agent is introduced into a conventional fabric dryer chamber or enclosure 27 having a conventional rotatable drum or agitator 27 and a door 29. Drum ribs 31 effect a thorough commingling of the pieces of washed but damp fabric 32 with the substrate with repeated random collisions. Vent 33 is provided, allowing escape of drying air and water vapor.

The normal drying time of about 40 to 60 minutes and the normal drying temperatures of about 120.degree.F. to 190.degree.F., commonly employed for laundry drying are satisfactory. High humidity conditions exist in the dryer, and by the time the fabric pieces have been dried, conditioning agent has been transferred from the substrate to the fabric and is randomly deposited thereon. Once deposited the softener may spread along the fabric surface. After the conditioning treatment, the dried pieces of fabric are removed from the dryer and handled in the customary manner, such as ironing.

EXAMPLE I

A conventional paper towel of about 105 square inches in size was immersed in a dispersion of 2.0 grams of dimethyl, di(hydrogenated tallow) ammonium chloride (a quaternary ammonium compound known as "Arquad 2HT-75" by Armour Chemical Company) in 7.0 c.c. of water and 1.5 c.c. of isopropanol, prepared at 18.degree.C. After all the liquid had been absorbed and the paper towel was dried at ambient temperature, 2.0 grams of the agent was impregnated uniformly in the body of the substrate leaving a surface coating, and the substrate was dried. The impregnated substrate carrying the agent was then introduced into a conventional household clothes dryer ("Kenmore" gas dryer) with an approximate 8 lb. load of damp fabrics (towels and linens) which had been spin-dried by centrifugation in the washer. During a conventional drying cycle of about 50 minutes under conventional drying temperature of about 150.degree.F., the substrate was thoroughly tumbled around with the fabric by the drying agitator.

During such treatment, the agent was removed from the surface of the substrate through abrasion and moisture transfer to fabric pieces rendering them noticeably softer, antistatic and fluffier. The thus imparted lubricating effect and resultant freedom from static reduced knotting and cloth binding, thereby substantially reducing wrinkling. The antistatic qualities remained with the fabric pieces until they were rewashed, thus rendering them more comfortable to wear; and because of the softening, the need for ironing was minimized and ironing was made easier.

EXAMPLE II

Fifty grams of the aforementioned quaternary ammonium compound of Example I, was dispersed in 15 c.c. of isopropyl alcohol and 70 c.c. of water at 75.degree.C. Ten conventional sheets of perforated paper toweling, each of 120 square inches, were folded along the perforations into a pad which was pressed into this dispersion, and was squeezed and worked until all the solution was evenly dispersed throughout the pad.

The pad was then unfolded and hung on a wash line to dry. Drying took about 10 hours at ambient temperature. After the drying, the impregnated sheets having a surface coating were very flexible, translucent and had a waxy feel. Checking the dry weight of the towels established that each sheet had picked up approximately 5 grams of the conditioning agent.

Over a period of several weeks, these towels were employed for conditioning fabrics by adding one towel to a conventional gas heated (Kenmore) clothes dryer with each load of approximately 8 lbs. of freshly laundered clothes to be dried; the drying temperature being about 150.degree.F., and the time about 50 minutes. After the drying, the clothes were removed and in each instance were softer, had fewer wrinkles, showed no electrostatic charge and ironed more easily. Each removed paper towel was intact, and had lost about 80 weight percent of the agent.

EXAMPLE III

A conventional resin sized (about 6 lbs. per ream) high wet strength Kraft paper, weighing 30 lbs, per ream (3,000 sq. ft.) and having a caliper of about 0.0043 inch, was coated with uniform distribution on one side with a melt of the conditioning agent of Example I in an amount of about 2.15 grams per sq. ft.

A 10 .times. 10 inch square of the thus coated paper was introduced into a conventional household dryer as in Example I with an approximate 8 lb. load of fabrics, and the fabrics were dried as in Example I. The fabrics dried in the presence of the coated substrate, as in this example, were considerably softer than closely similar fabrics which were treated with presently commercial liquid conditioning agents added to the fabrics in the last rinse of the washing cycle.

Claims

I claim:

1. A fabric conditioning article including a carrier comprising a web having a discrete surface coating of a normally-solid fabric softening agent; said web being resistant to shredding or tearing failure when tumbled with damp clothes in a laundry dryer; said coating having an irregular thickness ranging from about 0.1 to 10.0 mils., said normally-solid fabric softening agent comprising a material which has a softening temperature below the elevated temperatures of from about 120.degree.F. to 190.degree.F. encountered in a laundry dryer to thereby soften in said dryer and thus enhance transfer of the agent to fabrics contacted therewith; the amount of said fabric softening agent comprising from about 1.0 to 10.0 grams per 105 square inches of said web.

2. The article of claim 1 in which the web is of cellulosic fiber.

3. The article of claim 1 in which the web fibers are selected from the group consisting of rayon, nylon, polyester, polyacrylonitrile and polyolefin.

4. The article of claim 1 in which said web is of wet strength paper.

5. The article of claim 1 wherein the coating is a hot melt coating.

6. The article of claim 1 wherein the fabric softening agent is dimethyl di(hydrogenated tallow) ammonium chloride.

7. A package comprising a plurality of individual articles as claimed in claim 1.

8. An article for conditioning fabrics in a laundry dryer comprising a web having a discrete surface coating of fabric softening agent of the formula ##SPC9##

wherein R.sub.1 and R.sub.2 are each alkyl of from 12 to 22 carbon atoms, R.sub.3 and R.sub.4 are each lower alkyl and X.sup.- is selected from the group consisting of OH, Cl, Br, CH.sub.3 OSO.sub.3 and SO.sub.4 ; said fabric softening agent comprising a normally solid material which has a softening temperature below the elevated temperatures of from about 120.degree.F. to 190.degree.F. encountered in a laundry dryer to thereby soften in said dryer and thus enhance transfer of the agent to fabrics contacted therewith; said web being resistant to shredding or tearing failure when tumbled with damp clothes in a laundry dryer; said coating having an irregular thickness ranging from about 0.1 to 10.0 mils; the amount of said fabric softening agent comprising from about 1.0 to 10.0 grams per 105 square inches of said web.

9. The article of claim 8 in which the web fibers are selected from the group consisting of rayon, nylon, polyester, polyacrylonitrile and polyolefin.

10. The article of claim 8 in which said web is of cellulosic fiber.

11. The article of claim 8 in which said web is of wet strength paper.

12. The article of claim 8 wherein the fabric softening agent is dimethyl di(hydrogenated tallow) ammonum chloride.

13. Package according to claim 7 in which said plurality of individual articles are detachably connected together.

14. Package according to claim 13 in which the webs of the individual articles are in the form of a roll from which each individual article is separable along longitudinally spaced transverse lines of weakness.