US3891389A

US3891389A - Shrinkage-control treatment for knitted fabrics

Info

Publication number: US3891389A
Application number: US328199A
Authority: US
Inventors: Gerald B Verburg; Jr John G Frick; John D Reid
Original assignee: US Department of Agriculture USDA
Current assignee: US Department of Agriculture USDA
Priority date: 1973-01-31
Filing date: 1973-01-31
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24

Abstract

Durable-press knitted fabrics of cotton or cotton-synthetic fiber blends have been rendered essentially stable to laundering. Resistance to dimensional change in laundering has been attained by inducing shrinkage through a wet or dry agitation after treatment. Relatively little loss of fabric area occurs in the process.

Description

United States Patent 1191 Verburg et al.

[ 51 June 24, 1975 SHRlNKAGE-CONTROL TREATMENT FOR KNITTED FABRICS [75] Inventors: Gerald B. Verburg, Metairie; John G. Frick. Jr.; John D. Reid, both of New Orleans. all of La.

[73] Assignee: The United States of America, as

represented by the Secretary of Agriculture. Washington, DC.

22 Filed: .lan.3l, 1973 211 App]. No.: 328,199

[52] US. Cl. 8/1491; 8/183; 8/185;

8/186 [51] Int. Cl. D06c 1/02 [58] Field of Search 8/183. 185. 186, 149.2

[56] References Cited UNITED STATES PATENTS 3.257739 6/1966 Wentz 8/1492 X 3,660.013 5/1972 Payet et a1. .1 8/1493 X 3.738.019 6/1973 Forg et ul. 8/1492 X 3.739.496 6/1973 Buckley et al. 8/1493 X 3.765.580 10/1973 Wilsker et al n 8/1493 X Primary E.raminerStephen J. Lechert, Jr. Attorney. Agent, or Firm-M. Howard Silverstein; Max D. Hensley ABSTRACT 7 Claims, No Drawings SHRINKAGE-CONTROL TREATMENT FOR KNITTED FABRICS A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to the process of producing knitted cotton or cotton and synthetic fabrics that have substantially reduced shrinkage on laundering without causing severe losses of fabric dimensions to the manufacturer.

More specifically, this invention relates to an improvement in the process of producing durable-press knitted fabric of cotton or cotton and synthetics, the improvement characterized by subjecting the fabric after treatment with a finishing agent to a washing and drying procedure during which the fabric is agitated in a slack condition for a brief period only in either the washing or drying, or both, or in a separate operation after the drying, which provides the knitted fabric with substantially reduced shrinkage on laundering as well as smooth-drying properties and with relatively little loss of fabric length.

An additional benefit is that the improved process is applicable with more than one type of durable-press fabric treatment.

Another additional benefit is that the process reduces the chance of potentially harmful chemicals from coming into contact with the textile user either through di rect contact with the skin or through inhalation.

Shrinkage in knitted fabrics occurs when the strains built into the yarns by knitting and processing are gradually relieved on the agitation of washing and drying. The crosslinking of knitted cotton fixed the yarns in the strained position to a great extent. The amount of relaxation that occurs in repeated laundering is therefore reduced greatly. The relaxation and resultant shrinkage is small enough so that all but an unobjeetionable residual amount can be removed in a brief period of agitation in a wet or hot, dry state. This period can be made brief enough so that it could be included in a normal textile processing with little change of the process.

Untreated knitted fabrics of cotton or cotton and synthetics undergo dimensional changes on laundering to the extent that they are no longer satisfactory for the purpose intended. A certain amount of this distortion can be prevented by chemical treatment, but to retain the usefulness of the fabric, the amount of chemical treatment is limited due to the increase in stiffness and loss of strength that occur. In order to achieve dimensional stability in the present state of the art, a resin treatment to control part of the shrinkage is used in conjunction with a mechanical pre-shrinkage that is usually carried out before curing of the resin. This has certain disadvantages, one being large losses of fabric area to the manufacturer and the possibility of introducing wrinkles.

It is well known to those skilled in the art, that a cotton knit chemically treated without mechanical preshrinkage will change dimensionally a given amount on subsequent laundering. This change can be used to leave a fabric that is dimensionally stable. It can be divided by a number of processes between the manufacturer and the consumer so that both benefit. The manufacturer profits in that the amount of fabric lost for a given degree of subsequent laundry shrinkage control is less than that lost when mechanical pre-shrinkage is employed. The consumer benefits in that he has a fabric that is truly stabilized against dimensional changes. The added benefit of having noxious odors and toxic chemicals removed from the garments in the process wash before they come into contact with the consumer can also be realized.

In general, it is not a practice to wash textiles following treatments to improve appearance and/or dimensional stability. This is well known to those skilled in the art. It is considered to be especially detrimental to wash knit fabrics following treatments to improve appearance and/or dimensional stability. As disclosed by Bille, Thonig, and Schmidt in American Dyestuff Reporter, October, 1972, The finish should not require an afterwash so that tension deformation can be avoided." However, afterwashing (process washing) of knit fabrics in a slack condition seems to relieve most tensions that remain in the fabrics. This is illustrated by the fact that very little shrinkage occurs on subsequent laundering of fabrics which have been given a process wash.

Current practices in the art to achieve laundry stability are based mainly on mechanical methods and exclude the use of wet or moist cure processes. It is an added advantage of the instant invention that shrinkage control on laundering is achieved after the crosslinking step which allows the use of such methods as the moist cure process.

In the chemical treatment, the crosslinking agent, or resin, can be one of the polymethylolamide agents, or an agent derived from them, which are commonly used in the finishing of woven cellulosic fabric. These agents are prepared inexpensively from formaldehyde and an amido compound, and react readily with the cellulose of cotton. Typical examples are dimethylol ethyleneurea, dimethylol dihydroxyethyleneurea, dimethylol methyl carbamate, dimethylol ethyltriazone, and methylated trimethylol melamine. However, it is possible also to use other known types of crosslinking agents with their appropriate catalyst. in addition to crosslinking agent, the treatment may include other agents to modify the fabric, such as, hand builders, softeners, wetting agents, fire-retardants, preservatives and moisture inhibitors.

An object of the instant invention is to dimensionally stabilize cotton or cotton-synthetic knitted fabrics to the effects of laundering in a manner that will benefit the manufacturer as well as the consumer. Although there may be many variables to the instant invention which would be covered by the process of the invention, a preferred embodiment is the treating of knitted cellulosic fabrics by ordinary pad-dry-cure techniques wherein the fabric is impregnated with an aqueous solution containing about 6% of dimethylol dihydroxyethyleneurea which is commonly used in the finishing of cellulosic fabrics, about 0.6% hydrated zinc nitrate to catalyze the crosslinking reaction, about 0.5% of a polyethylene softener, and about 0.1% of a wetting agent. The treating bath is applied to the knitted cotton fabric by a device such as pad rolls that apply a controlled amount of the bath liquor and distribute it uniformly on the fabric. The fabric is dried after application of the treating bath and then heated briefly, or cured, to promote the crosslinking reaction. After curing, shrinkage is induced in the treated fabric by washing and drying during which the fabric must be slack for at least part of one of the operations. The shrunken fabric may then be incorporated into garments without the hazard of distortion and shrinkage of such garments during subsequent laundering.

Or simply, the instant invention consists of, in the process of producing durable-press knitted fabrics of cotton or cotton and polyester, the improvement characterized by subjecting the fabric after treatment with the finishing agent to a washing and drying procedure during which the fabric is agitated in a slack condition in either the washing or drying, or both, or in an operation after drying, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering as well as smooth drying properties and with relatively little loss of fabric length.

Also, it consists of, in the process of producing durable-press knitted fabric of cotton, the improvement characterized by subjecting the fabric after treatment with the finishing agent to a drying procedure during which the fabric is agitated in a slack condition, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering, and in which relatively little fabric length has been lost.

Also, it consists of, in the process of producing durable-press knitted fabric of cotton, the improvement characterized by subjecting the fabric after treatment with the finishing agent to a washing and drying procedure in which the fabric is agitated in a slack condition for a brief period, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering, and in which relatively little fabric length has been lost.

Also, it consists of, in the process of producing durable-press knitted fabric of cotton, the improvement characterized by subjecting the fabric after treatment with the finishing agent to a washing and drying procedure, in which the fabric is held to size, followed by agitation in the slack condition with heat for a brief period, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering and causes relatively little loss of fabric length.

EXAMPLES The following examples are provided to illustrate the practice and results of the process of the instant invention and are not in any way intended to limit the scope of the invention. Percentages shown in the examples relating to concentrations have reference to percentage by weight of the total treating formulation. The various fabric samples were tested by the following methods: dimensional stability was determined by measuring the changes in fabric dimensions from an original inch by 10 inch set of markings, templated before the fabric was subjected to the initial processing step; durablepress rating by comparison with plastic replicas as described in AATCC Tentative Test Method l24-l967.

EXAMPLE 1 A 50% solution of dimethylol didhydroxethyleneurea (DMDHEU) was diluted with sufficient water to give a 6% solids concentration, 0.6% by weight of hydrated zinc nitrate (Zn(NO .6H O) added as catalyst, 0.5% emulsified polyethylene added as a softener, and 0. l% alkyl aryl ethyleneoxide alcohol added as a wetting agent. This treating solution was padded onto a sample of 5.3 ounces per square yard cotton jersey knitted fabric, so that the finished fabric contained 0.69% nitrogen. The wet impregnated fabric was dried for 20 minutes at 65C and then cured 3 minutes at lC while the fabric was secured in a frame to maintain a 4% stretch in the lengthwise and widthwise directions.

The curing step was followed by a process wash in a washing machine at 62C for l2 minutes with a nonionic detergent. The washed fabric was tumbled in a drum-type gas drier for 35 minutes between 6577C. The process washed fabric exhibited a shrinkage of 3.4% in the lengthwise direction and 2.2% in the widthwise direction and a durable-press rating of 3.8.

The process wash was followed by six laundry cycles, using a home-type washing machine and dryer. The laundered fabric exhibited a shrinkage of only 2.1% in the lengthwise direction and l.l% in the widthwise direction and had a durable-press rating of4.0. The original fabric was laundered with the treated and processwashed fabric and it exhibited a shrinkage of about 3l% in the lengthwise direction and about 8% in the widthwise direction. The results given in this example are average values from multiple experiments.

EXAMPLE 2 This treatment was identical to that in Example 1 through the curing step, after which, the fabric was sprayed with a 2% solution of a nonionic detergent in water and washed while held to size on the pin frame with hot running tap water for ID minutes, allowed to drain, dried for 20 minutes at 65C, removed from the pin frame and tumbled for 35 minutes between 6577C in a drum-type gas drier. The dried fabric exhibited an induced shrinkage of 5.5% in the lengthwise direction and 3.3% in the widthwise direction.

After shrinkage was induced into the fabric, it was laundered five times, as in Example 1. The laundered fabric exhibited a shrinkage of only 2.7% in the lengthwise direction and 0.4% in the widthwise direction.

EXAMPLE 3 This treatment was identical to that in Example 1 through the curing step, after which, the fabric was sprayed with a 2% solution of a nonionic detergent in water and washed while on the pin frame with hot running tap water for 10 minutes, allowed to drain, removed from the pin frame and tumbled for 35 minutes between 65-77C in a drum-type gas drier. The dried fabric exhibited an induced shrinkage of 5.3% in the lengthwise direction and 4.2% in the widthwise direction.

After shrinkage was induced into the fabric, it was laundered five times, as in Example 1. The laundered fabric exhibited a shrinkage of only 2.3% in the lengthwise direction and 0.6% in the widthwise direction.

EXAMPLE 4 This treatment was identical to that in Example I through the process wash, after which, the fabric was pin framed as near to the existing dimensions as possible and dried for 20 minutes at 65C. The dried fabric exhibited an induced shrinkage of 5.0% in the lengthwise direction and 2.8% in widthwise direction.

After shrinkage was induced into the fabric, it was laundered five times, as in Example l. The laundered fabric exhibited a shrinkage of only 2.8% in the lengthwise direction and 1.6% in the widthwise direction.

EXAMPLE 5 A sample of 4.8 ounces per square yard of 50% cotton and 50% polyester jersey knitted fabric was processed in a manner identical to that described in Example l. The process-washed fabric exhibited a shrinkage of 4.4% in the lengthwise direction and 5.8% in the widthwise direction.

The process wash was followed by five laundry cycles each one similar to the process wash. The laundered fabric exhibited a shrinkage of only 1.7% in the lengthwise direction and 08% stretch in the widthwise directron.

EXAMPLE 6 The treatment was identical to that in Example 1 through the curing step, after which, the fabric was washed in a top'loading, washing machine at 62C for 1 minute. The fabric was passed through squeeze rolls to remove most of the water. The remaining water was removed by tumbling in a home-type, gas drier for minutes between 6577C. The fabric exhibited a shrinkage of 5.8% in the lengthwise direction and 3.7% in the widthwise direction.

After shrinkage was induced into the fabric, it was laundered five times, as in Example 1. The laundered fabric exhibited a shrinkage of only 2.1% in the lengthwise direction and 1.2% in the widthwise direction.

EXAMPLE 7 This treatment was identical to that in Example 1 through the curing step, after which, the fabric was tumbled in a drum-type gas drier for 35 minutes between 6577C. The tumbled fabric exhibited an induced shrinkage of 4.9% in the lengthwise direction and 2.6% in the widthwise direction.

After shrinkage was induced into the fabric, it was laundered five times, as in Example 1. The laundered fabric exhibited a shrinkage of only 2.5% in the lengthwise direction and 0.8% in the widthwise direction.

EXAMPLE 8 This treatment was identical to that in Example 1 through the curing step, after which, the fabric was tumbled in a drum-type gas drier for 5 minutes between 6577C. The tumbled fabric exhibited an induced shrinkage of4.3% in the lengthwise direction and 2.6% in the widthwise direction.

After shrinkage was introduced into the fabric, it was laundered five times, as in Example 1. The laundered fabric exhibited a shrinkage of only 3.3% in the lengthwise direction and 1.8% in the widthwise direction.

EXAMPLE 9 This treatment was identical to that in Example 1 through the curing step, after which, the fabric was washed in a washing machine at 62C briefly for 1 minute. The fabric was passed through squeeze rolls to remove most ofthe water. The remaining water was removed by drying in a slack condition in an oven without tumbling for 5 minutes at l 15C. The fabric exhibited a shrinkage 0f4. 1% in the lengthwise direction and 2.2% in the widthwise direction.

After shrinkage was induced into the fabric, it was laundered five times, as in Example 1. The laundered fabric exhibited a shrinkage of only 3.5% in the lengthwise direction and 1.8% in the widthwise direction.

EXAMPLE 10 The treatment was identical to that in Example 1 through the curing step, after which, the fabric was sprayed with a 2% solution of a nonionic detergent in water and washed while on the pin frame with hot running tap water for 10 minutes, allowed to drain, and dried for 20 minutes at C while on the pin frame. The fabric was tumbled in a slack condition for 3 minutes between 65-77C in a drum-type gas drier. The dried fabric exhibited an induced shrinkage of 4.7% in the lengthwise direction and 2.4% in the widthwise direction.

After shrinkage was induced into the fabric, it was laundered five times, as in Example 1. The laundered fabric exhibited a shrinkage of only 3.5% in the lengthwise direction and 1.2% in the widthwise direction.

EXAMPLE 1 l A 50% solution of dimethylol dihydroxyethyleneurea (DMDHEU) was diluted with sufficient water to give a 6% solids concentration and 0.33% hydrogen chloride (HCl) added as a catalyst. This treating solution was padded onto a sample of 5.3 ounces per square yard cotton jersey knitted fabric, so that the finished fabric contained about 0.65% nitrogen. The wet impregnated fabric was secured in a frame to produce a 4% stretch in the lengthwise and widthwise directions. The fabric was dried with a forced air flow at ambient temperatures to about 9% moisture and placed in a sealed plastic bag for curing at about 23C for about 20 hours during which the stretch was maintained.

The curing step was followed by a process wash in a washing machine at 62C for 12 minutes with a nonionic detergent. The washed fabric was tumbled in a drum-type gas drier for 35 minutes between 6577C. The process-washed fabric exhibited a shrinkage of 8.3% in the lengthwise direction and 4.7% in the widthwise direction and a durablepress rating of 3.4.

The process wash was followed by six laundry cycles using a home-type washing machine and drier. The laundered fabric exhibited a shrinkage of only 2.2% in the lengthwise direction and 1.1% in the widthwise direction and a durable-press rating of 3.3. The results given in this example are average values from multiple experiments.

We claim:

1. In the process of producing finished, durable pressed, knitted, cotton-containing garments wherein cotton-containing knit fabric is crosslinked to impart durable-press characteristics to the fabric and then formed into garments, the improvement comprising agitating the fabric in a slack condition after said fabric is crosslinked but before it is formed into a garment.

2. The process of claim 1 wherein the fabric is agitated while being washed.

3. The process of claim 1 wherein the fabric is agitated in hot air.

4. The process of claim 1 wherein the fabric is agitated while being washed and dried.

5. 1n the process of producing durable-press knitted cotton-containing fabric. the improvement comprising subjecting the fabric after treatment with a finishing agent to drying during which the fabric is agitated in a slack condition, which provides the knitted fabric with substantially reduced shrinkage on subsequent launder- 7. In the process of producing durable-press knitted cotton-containing fabric, the improvement comprising subjecting the fabric after treatment with a finishing agent to washing and drying in which the fabric is held to size, followed by agitation in the slack condition with heat for a brief period, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering and causes relatively little loss of fabric length.

Claims

1. IN THE PROCESS FO PRODUCING FINISHED, DURABLE-PRESSED, KNITTED, COTTON-CONTAINING GARMENTS WHEREIN COTTON-CONTAINING KNIT FABRIC IS CROSSLINKED TO IMPART DURABLE-PRESS CHARACTERISTICS TO THE FABRIC AND THEN FORMED INTO GARMENTS, THE IMPROVEMENT COMPRISING AGITATING THE FABRIC IN A SLACK CONDITION AFTER SAID FABRIC IS CROSSLINKED BUT BEFORE IT IS FORMED INT A GARMENT.

2. The process of claim 1 wherein the fabric is agitated while being washed.

3. The process of claim 1 wherein the fabric is agitated in hot air.

5. In the process of producing durable-press knitted cotton-containing fabric, the improvement comprising subjecting the fabric after treatment with a finishing agent to drying during which the fabric is agitated in a slack condition, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering, and in which relatively little fabric length has been lost.

6. In the process of producing durable-press knitted cotton-containing fabric, the improvement comprising subjecting the fabric after treatment with a finishing agent to washing and drying in which the fabric is agitated in a slack condition for a brief period, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering, and in which relatively little fabric length has been lost.

7. In the process of producing durable-press knitted cotton-containing fabric, the improvement comprising subjecting the fabric after treatment with a finishing agent to washing and drying in which the fabric is held to size, followed by agitation in the slack condition with heat for a brief period, which provides the knitted fabric with substantially reduced shrinkage on subsequent laundering and causes relatively little loss of fabric length.