Absorbent Panty

Abstract

An absorbent panty has good resistance to discoloration and great retention of absorbency over a life of washings by utilizing a crotch insert or interliner fabricated of hydrophilic fibers needle punched into a non-woven spunbonded inelastic hydrophobic fiber sheet.

Description

This invention relates to garment construction and more particularly to the construction of garments of the type used for infants as training panties or for incontinent medical patients.

The prime objective of garment manufacturers is to provide in such garments a high degree of absorbency without undue bulk but with an eye also to cost economy. The latter factor dictates use of minimal amounts of woven or knit fabrics with the result that some of the present baby training panties have crotch inserts of extensible elastic polyurethane foam into which absorbent fibers have been needled. Such needled foam is referred to as "batt foam" or "fiber sponge."

The theory has been that such foam functions to elastically grab and anchor the needled fibers while also giving a sponge-like absorbency and stretchability through the crotch compatible with the desired stretch characteristics of the garment. Such panties have found wide acceptance even though they have encountered certain consumer dissatisfaction. First, polyurethane foam discolors badly in any washing involving exposure to chlorine. Since whiteness in cotton panty type garments of this type is an indicia of sanitariness, it is highly desirable that such garments maintain their whiteness during normal lifetime use. Home washing procedures using ordinary household laundry detergents, particularly the less efficient, low phosphate detergents presently marketed, are not effective for complete removal of excretory stains. Generally, one practical and very effective method of removing these stains and of maintaining whiteness is by procedure of home bleach washing with "Clorox." An inherent characteristic of bleach washing is garment sanitation, i.e., removal of odor and destruction of bacteria regardless of detergent inefficiency or inadequacy of wash temperature. This method of washing, however, is not effective for imparting whiteness to garments having a foam product interliner. An anomaly of such garments is that after "Clorox" washing, the garment appears to become browner in color rather than whiter. For example, after one domestic bleach wash, the foam turns brown and this color visible through the fabric of the outer liner gives the garment a brown discolored appearance. This apparent discoloration of the center panel gives the garment an unattractive appearance and is suggestive of excretory stains that were not completely washed out. Secondly, despite the elastic grab of the foam, there has been dissatisfaction with the permanency of the absorbent fiber anchorage. The mechanical flexing encountered in repeated washings and tumble dryings tends to loosen the fibers with the result that they become completely separated from the foam and ball up together in uneven lumpy accumulations. If reliance has been placed upon wicking action through the foam, displacement of the absorbent fibers terminates the wicking and the original level of absorbency is no longer present. Some time before half life of the garment, the foam crumbles and entirely disintegrates. For these reasons mothers feel they have been cheated out of some portion of the normal garment wear because of discoloration or development of unacceptably uncomfortable lumps, particularly because chlorine-containing Clorox is a very popular bleach.

Despite these complaints, the present day needled polyurethane foam insert has continued to enjoy popularity as the last word from the standpoint of proper training panty function and comfort, with the result that the additional complication of observing very careful handling requirements to prevent the desired white foam from deterioration or color change by exposure to light during transit, storage and garment fabrication has been regarded as warranted. The foam must be kept covered as much as possible even during cutting operations. Otherwise the yellow-brown discoloration is visible through the outer fabric of the panty and the overall effect is that the garment appears to have a discolored or dirty crotch portion even after adequate laundering. Urethane foam also has shrinkage problems. Urethane foam is also a scavenger of color if washed with colored garments it picks up and holds the color -- becomes an undesired colored crotch.

In garments constructed in accordance with the present invention, the polyurethane discoloration problem is completely eliminated by not using polyurethane and the absorbent fiber detachment and migration is eliminated or greatly lessened by using a non-elastic substantially inextensible or only slightly extensible substrate for the absorbent fiber. To this end, garments of this invention utilize for absorbent purposes preferably as a crotch insert layer, a spunbonded continuous filament non-woven hydrophobic fiber sheet, e.g., of nylon, to which has been attached by a needling process a batt or web of absorbent fibers such as staple viscose or acetate rayon. The spunbonded sheet may be needle-punched into the center of the fabric or needle-punched to the bottom of the fabric. The generic term "spunbonded" is used to describe a non-woven sheet material made from randomly arranged continuous filament fibers which are highly dispersed (highly separated) and bonded together at filament crossover points. The filaments may have crimp or even considerable free fiber length between bonds. The unique spunbonded construction provides a high tensile and tear strength at low cost and weight. Strengths are uniform in all directions throughout the non-woven sheet and are greater than woven fabrics of the same weight.

While it might be expected that conversion to an inelastic substrate such as that provided by the spunbonded sheet would adversely affect the permanency of the grab on absorbent fibers and also cause unacceptable discomfort from loss of stretchability in the crotch, such consequences have been found not to result. In fact the permanency of anchorage of the fibers seems to be superior. In fact the original absorbency of the insert is fully retained after as many washings as occur in the average lifetime of such garments, i.e., after 50 washings or more. The necessity of stretchability becomes pretty much of a myth provided the substrate has as great tensile strength as does the sheet insert of this invention. The anchorage in any event is so good that it is unnecessary to use an expensive fiber anchoring process such as that referred to in U.S. Pat. No. 3,368,563 to offset the fall out characteristic of fibers which are merely needled into a stretchable substrate. Looking at the matter another way, by using a substrate which has little or no extensibility, the anchorage is so improved that needling alone can be relied upon to attach the absorbent fiber and keep it attached despite repeated washings without resorting to expensive anchoring processes of the type referred to in the aforesaid patent. Moreover the needling does not adversely affect the strength and tear properties of the substrate.

The preferred base or substrate for immobilizing the absorbent fibers is a 0.6 ounce per square yard spunbonded nylon having an average thickness of 5.1 mils and a Mullen burst of 15.4 lbs., being a product of Monsanto Chemical Company furnished under the trademark CEREX.

To this is attached a batt of absorbent fibers which contains about 4.5 ounces per square yard. A preferred fiber is a virgin white dull 11/2 denier 2 inch staple viscose fiber.

FIG. 1 is an exterior view of a conventional training panty having a front portion 22, two side portions 24 and 26 and a back portion 28 which can be integral with the front portion 22, all the portions forming a waist opening 30 and two leg openings 32 and 34. The waist opening is provided with an elastic ribbon 36 to provide elasticity.

FIG. 2 is a cross sectional view taken along the line 2--2 of FIG. 1 showing the waistband structure including the elastic ribbon 36.

FIG. 3 is a cross sectional view taken along the line 3--3 of FIG. 1 showing the seaming of the central portion to one of the side portions 26 and FIG. 4 is a cross sectional view taken along the line 4--4 of FIG. 1 showing how the central portion is seamed to the trim 46 of the leg openings.

As shown by the cut-away portion in the front of FIG. 1 the front, back and crotch portions are formed of an inner layer of knit fabric 40, an outer layer of knit fabric 44 and an absorbent interliner 42 sandwiched between, all of which are seamed to the single thickness side portions 24 and 26 and to portions of the leg openings.

Normally the knit fabric portions of the garment are made from cotton yarn but the inner knit layer 40 which extends through the crotch may include a certain portion or be made entirely of hydrophobic fibers such as polyolefin yarn.

Suitable hydrophilic fibers for needle punching include cotton, viscose and cuprammonium rayon. Viscose rayon is preferred because it has the highest saturation regain and lowest cost. It is ideally suited as an absorbent for panty garments of "training panty" type or "adult diaper" type. The fiber needle punched Cerex interliner overcomes all of the disadvantages of the fiber needle punched foam interliner and is less bulky because of the thinness of the spunbonded sheet.

Other spunbonded hydrophobic non-wovens such as polyester (available under the trademark Reemay from DuPont) or polyolefin (available under the tradename Tyvek) may also be used as the wicking substrate.

Claims

What is claimed is:

1. A panty type garment having front, back and side portions, said front and back portions being joined by a crotch portion, all said portions forming a waist opening and two leg openings for said garment

said crotch portion containing a layer of absorbent fibers needled into a substrate comprising a spunbonded continuous filament hydrophobic fiber sheet.

2. A panty type garment as claimed in claim 1 wherein said substrate is a substantially inextensible inelastic sheet.

3. A panty type garment as claimed in claim 1 wherein said sheet is a continuous filament nylon sheet.

4. A panty type garment as claimed in claim 1 wherein said garment has front, back, side and crotch portions formed of knit fabric and said layer is sandwiched between two layers of said knit fabric.