Method of making laminated structures having gathered and ungathered marginal portions

A laminated structure having a marginal area with gathered and ungathered portions which provide an improved fit about a portion of the human body, said laminated structure comprising an elastic member disposed between first and second substrates of flexible gatherable material, said elastic member comprising a plurality of longitudinally extending elastic elements with the elements transversely connected over a portion of their length to define apertures and an end portion of the member comprising only longitudinally extending elements and the first and second substrates of said laminated structure being secured together through at least some of said apertures.

BACKGROUND OF THE INVENTION 
Recent years have seen an increased demand for inexpensive apparel and the 
development of new and inexpensive components of construction and methods 
of construction of articles of apparel. In certain instances, there is a 
demand for apparel that is very inexpensive and, indeed, disposable. New 
elastomeric materials and methods of incorporating them into portions of a 
garment have been developed to meet the desire to fit these types of 
garments to a human form. For example, U.S. Pat. No. 3,639,917 discloses 
the use of a strip of a heat recoverable elastomeric material to gather 
the cuff of a disposable hospital gown. 
Disposable diapers have been marketed which include an elastic or stretch 
member in the longitudinal side edges of the disposable diaper to provide 
elasticity about the leg of the infant when the diaper is applied. 
Examples of such stretchable fitted diapers which have elastic members 
disposed in the longitudinal side edges of the diaper are shown in U.S. 
Pat. Nos. 3,860,003 and 4,050,462. By being able to elastically contract 
the longitudinal sides of the diaper which are the leg and thigh 
encircling portion of the diaper once placed on an infant, you can 
compress the diaper about the leg of the infant. By virtue of this 
compressing, you reduce leakage at the leg of the infant and the tighter 
you make the fit, the more you tend to reduce leakage. However, if the fit 
is too tight, you will cause irritation on this tender portion of the 
thigh, especially when the diaper is wet. There are also a number of 
patents which disclose means for making the waist encircling portion of a 
disposable diaper elastic for tighter fit of the diaper about the waist of 
the wearer, for example, as shown and described in U.S. Pat. Nos. 
3,995,637 and 3,995,640. 
Disposable diapers usually comprise a facing and a backing layer which is 
substantially co-extensive and a somewhat smaller absorbent core or panel 
interposed between the facing and backing layer. The facing and backing 
layers are adhered together about their perimeter by hot melt adhesive or 
other adhesive material as is well known. In producing stretch or elastic 
diapers, an elastic member in its stretched or partially stretched state, 
is interposed between the facing and backing sheets along one or more 
edges of the diaper. The elastic member is adhered either to the facing 
and/or the backing sheets by adhesive or similar means and allowed to 
relax to produce elastic sections at the edges of the diaper. An example 
of a method for inserting elastic members in disposable diapers is 
disclosed in U.S. Pat. No. 4,081,301. 
The incorporation of these elastic members into disposable diapers has 
increased both the cost of materials used in the diaper and the cost of 
construction of disposable diapers. With solid elastic members, it is 
necessary to adhere the side edges of the facing and backing sheets 
together, either directly or by their mutual attachment to the elastic 
member. 
When adhesively securing such an elastic member into a disposable diaper, 
the adhesive chosen must be elastomeric or must be applied in a 
discontinuous pattern or the glue may make the diaper too stiff to gather. 
In commonly assigned co-pending patent application, Ser. No. 60,704, filed 
July 25, 1979, now abandoned there is disclosed apertured elastic members 
which have substantial advantages over other types of elastic members in 
that they are simpler and more economical to insert and function very well 
by providing a good fit with a minimum of irritation. The present 
invention is an improvement on such apertured elastic members. 
SUMMARY OF THE INVENTION 
What I have discovered is an improved laminated structure having a marginal 
area with a gathered portion and an ungathered portion which provide 
improved fit about a portion of a human body and a method of making the 
same. The laminated structure comprises first and second substrates of 
flexible, gatherable material and an elastic member disposed between the 
substrates in the marginal area thereof. The elastic member comprises a 
plurality of longitudinally extending elastic elements. The longitudinal 
elements are transversely connected over a portion of their length and 
define apertures therebetween. The first and second substrates are secured 
together through at least some of the apertures. 
An end portion of the elastic member has only longitudinally extending 
elements; i.e., these elements are not transversely connected or 
interconnected. The transversely connected elements provide a gathered 
marginal portion and the non-interconnected elements provide an ungathered 
marginal portion. 
The laminated structure of the present invention may be used in any fitted 
garment but perhaps is most suited for use in inexpensive and disposable 
apparel. The laminated structure can be incorporated into the sleeve cuff, 
the leg encircling portion, about the neck, and the waist of an article of 
apparel. In particular, the laminated structure may be incorporated into 
both the waist and thigh encircling portions of a disposable diaper or 
other disposable undergarments. The improved laminated structure of the 
present invention reduces the pressure applied to the skin of the wearer 
and, in a disposable diaper or a disposable undergarment reduces the 
possibility of irritation and rash when wet. 
In accordance with the present invention, the new and improved elastic 
member can be readily inserted in a stretched condition between the first 
and second substrates and these substrates easily adhered together to hold 
the elastic member in place, at high speeds, with good reliability and at 
reduced costs. Surprisingly, when the new and improved elastic member is 
severed in the area of the member where the longitudinally extending 
elastic elements are not transversely connected or interconnected, these 
unconnected portions of the elements will relax and contract to their 
original unstretched state and will not gather the substrates; whereas, 
the interconnected or apertured portion of the elastic member will act to 
gather the substrates. 
The elastic member has a width of from about 1/4 inch to about 2 inches and 
the member may have a thickness of from 1 to 50 mils and preferably from 
about 5 to 20 mils. The elastic member may be made of any of the standard 
film materials which are stretchable and are recoverable and have a 
modulus of elasticity at 100 percent elongation of from about 20 to 2000 
lbs./sq. inch. In a disposable diaper in accordance with the present 
invention, the elastic member may be disposed between the backing and 
facing sheet of the diaper in the longitudinal side margins of the diaper. 
In a preferred embodiment of a disposable diaper of the present invention, 
the central portion of the elastic member comprises interconnected 
longitudinally extending elastic elements which define apertures and this 
central portion acts to gather the side margin of the diaper. The two end 
portions of the elastic member comprise non-interconnected longitudinally 
extending elements in a relaxed and unstretched state and which do not act 
to gather the side margins of the diaper. 
In one method of the manufacture of a disposable diaper incorporating the 
laminated structure of the present invention, the facing and backing 
sheets of the diaper are adhesively secured together as in the past; i.e., 
adhesive is placed on the backing and the absorbent core is secured to the 
central portion of the backing sheet and the facing sheet is adhered at 
the edges. The elastic member is disposed in one or more of the edges of 
the backing and the adhesive disposed on the backing is allowed to adhere 
to the facing sheet through the open areas of the elastic member. 
In the production of disposable diapers in accordance with one embodiment 
of the present invention, a continuous web has lines of adhesive placed on 
its surface. Absorbent batts are placed in spaced relationship along with 
web. Elastic members in a stretched condition are disposed along each 
longitudinal edge of the continuous web. The elastic members have 
alternating interconnected portions and non-interconnected portions as 
previously described. The elastic members are positioned so that an 
interconnected portion is placed adjacent approximately the center third 
or so area of an absorbent batt with a non-interconnected portion 
extending to approximately the center third or so area of the adjacent 
batt. A second continuous web is placed on top of the batt and is urged 
against all of the marginal areas surrounding the batt to be secured to 
the bottom web by the exposed adhesive lines. The two webs are secured 
together through the open areas in both the interconnected and 
non-interconnected portions of the elastic members. Individual diapers are 
produced by severing this laminate between absorbent batts. In so doing, 
the elastic member is severed in a non-interconnected area and when 
severed the elastic member contracts. The interconnected portion of the 
elastic member gathers the longitudinal side margin of the diaper and the 
non-interconnected portions of the elastic member relax and contract to an 
unstretched state without gathering the side margin of the diaper. 
It should be pointed out that by using the elastic members in accordance 
with the present invention, the insertion of the member into the product 
and the adherence thereto is greatly simplified and, hence, has 
considerable economic benefit in the manufacturing process. The apertured 
portion insures a uniform, intermittent lamination between the elastic and 
non elastic layers and combined with the non-interconnected portions 
reduces the criticality of adhesive application. Also, the apertures 
combined with adhesion of the layers through these apertures provides that 
the final lamination acts or performs in its stretch, recovery and similar 
elastic properties substantially the same as the original elastic member, 
thus allowing for greater certainty in predicting the quality and 
functionality of the final product.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
For a laminated structure of the present invention, the elastic member is a 
readily stretchable, preferably thermoplastic member that possesses a 
certain minimum elastic recovery. 
The term "elastic" as used herein, refers to sheets, films, ribbons, 
filaments, and the like which have a recovery of at least 90 percent, when 
enlongated to within 10 percent of their field Point and measured in 
accordance with the following formula: 
##EQU1## 
where; L.sub.o =original length of sample 
L.sub.e =fully extended length 
L.sub.t =length of sample measured three seconds after release from 
extended length 
The thickness of the elastic member may be from about 1 to 50 mils and is 
preferably from about 5 to 20 mils. They have a width of from 1/4 inch to 
2 inches and preferably in diaper applications widths of from 1/2 inch to 
1 inch have been found satisfactory. For ease of stretchability, the 
modulus of elasticity of the elastic member at 100 percent elongation 
should not exceed about 2000 lbs./sq. inch. The modulus of elasticity is 
preferably substantially less than 2000 lbs./sq. inch, and most preferably 
is about 75 to about 400 lbs./sq. inch. 
As shown in FIG. 1, the elastic member 20 useful in accordance with the 
present invention comprises a plurality of longitudinally extending 
elastic elements 21. These elements are transversely connected in 
intermittent areas 22 of the member which areas alternate with areas 23 
wherein the longitudinally extending elastic elements are not transversely 
connected. The transversely connecting members 24 may or may not be 
elastic. However, as will be hereinafter described, the elastic members 
are preferably made from a single component and, hence, the properties of 
the member are substantially uniform throughout the member. The opening in 
the transversely connected areas 22 may have any shape such as square, 
oval, round, rectangular, triangular, or the like. Either square or 
rectangular shaped openings are preferred with the longitudinal and 
transverse elements perpendicular to each other. This configuration 
virtually eliminates any "necking down", reduction in the transverse 
dimension when the member is stretched longitudinally, and hence 
facilitates insertion of the member with the product and the adhesion of 
the layers of the laminate through the openings in the elastic member. The 
openings in the non-transversely connected areas 23 are usually very long, 
narrow areas. Depending on the modulus of elasticity of the material used 
and the thickness and width of the member, the number of openings in the 
transversely connected areas may vary from two to 100 openings per linear 
inch in both the longitudinal and transverse direction of the member. In 
addition, the elastic elements in the longitudinal direction may be of 
different widths, sizes or even shapes as compared to the elements in the 
transverse direction, and the spacing between the elastic elements may 
vary from the transverse to the longitudinal direction. 
Referring to FIG. 2, a disposable diaper 25 embodying the present invention 
has longitudinal side margins 26 and 27. The central portion of each side 
margin is gathered to provide improved fit about the baby's thighs. The 
elastic member 28 and 29 in each of the longitudinal side margins is an 
elastic member according to the present invention. Individual components 
of the disposable diaper of FIG. 2 are illustrated in FIG. 3. The diaper 
additionally includes a first layer or backing layer 30 made of a 
moisture-impermeable material, a rectangular absorbent batt 31 
superimposed over backing layer 30 and secured thereto by a series of glue 
lines 35 deposited on the backing layer, and a second layer or facing 
layer 32 made of a moisture-permeable web and positioned in superimposed 
relationship to the absorbent batt. The absorbent batt is of smaller area 
than the backing and when substantially centered to the backing, is spaced 
from the longitudinal sides as well as the transverse ends of the diaper. 
The absorbent batt is flanked on its longitudinal sides by elastic members 
28 and 29 located generally parallel the longitudinal edges of the batt 
and which, in an extended state, are secured between the backing and the 
facing by means of the adhesive lines 35. A moisture-pervious facing 31 is 
superimposed over the absorbent batt and secured to the backing by means 
of the end and side portions of the glue lines 35. The facing is also 
secured to the backing between the openings in the elastic member. For 
securing the diaper about a baby, the diaper is provided with 
pressure-sensitive tape tab members 33 and 34. 
In the manufacture of the diaper, only the central portions 36 and 37 of 
the elastic members 28 and 29 act to gather the longitudinal side margins 
of the diaper. The end portions 38 which comprise the non-transversely 
connected portions of the elastic members, merely "snap back" to a 
relaxed, unstretched state and do not act to gather the diaper. The use of 
the elastic member of the present invention provides a reduction in cost 
of materials over a solid elastic member of the same length and width used 
to apply a gathering force to the longitudinal side margins. 
The elastic member of the present invention may be produced by a variety of 
methods such as passing an appropriate stretchable and recoverable film 
between the nip of a pattern forming roll and a back-up roll in a 
procedure analogous to that shown in U.S. Pat. Nos. 3,881,381 and 
3,632,269. When using such a procedure, the pattern of the forming roll 
should be altered to provide for the alternating areas of transversely 
connected longitudinally extending elements and non-transversely connected 
longitudinally extending elements. However, if a uniform pattern is used 
as disclosed in the above-mentioned patents, it is a simple matter to 
merely sever the transversely connecting elements between longitudinal 
elements to render the longitudinal elements unconnected or even remove 
the transverse elements in certain areas to render those areas not 
transversely connected. 
FIG. 4 shows another disposable diaper 40 similar to that shown in FIG. 2 
with the exception that all four edge portions; that is, the two 
longitudinal side margins 41 and 42 and the front 43 and rear 44 end 
portions are elastic members in accordance with the present invention 
inserted between the facing and the backing with the central portions 
thereof elastic. 
FIG. 5 shows a disposable diaper 50 similar to the diaper depicted in FIG. 
2 with the exception that the reticulated elastic member 51 is only in the 
central front waist portion 52 of the diaper to provide improved fit about 
the baby's waist. 
In the embodiment shown in FIG. 6, a disposable diaper 60 is provided with 
a substantially rectangular panel 61 sandwiched between a backing 62 and 
facing 63 and together with the backing and facing define side margins 64 
and 65. Curvilinear cut-outs are provided in the respective central side 
portions of the facing and backing for further fit enhancement. 
Pre-stretched elastic members 68 are positioned in the longitudinal side 
margins and are secured between the backing and facing along the 
longitudinal sides of the absorbent panel. The elastic members have been 
relaxed and retracted from their original end position at 69 and 70. Glue 
lines 71 secure the facing and absorbent panel to the backing and adhesive 
tape tabs 72 and 73 provide diaper securement means. 
Referring to FIG. 7, which is a cross-sectional view taken along 7--7 of 
FIG. 6, there is shown the impervious backing member 62 with the elastic 
member 68 secured between the backing member and the facing member 63 by 
the glue lines. 
In the embodiment shown in FIG. 8, the disposable diaper 80 is provided 
with an absorbent batt 81 and also having curvilinear side cut-outs and 
sandwiched between facing 82 and backing 83 having similar cut-outs. Glue 
lines 84 serve to secure the batt and facing to the backing. Elastic 
members 85 are situated in the general rectilinear diaper side margins. 
The elastic members are secured between the facing and backing at the 
central portion 86 by adhesive lines 88 which may be applied at the same 
time as, and may lie along the same line as certain of the glue lines 84. 
Protruding portions 89 and 90 of the absorbent batt overlap into the four 
corners of the diaper. 
The elastic members suitable for use in the diapers contemplated may be 
made from films extruded, calendered, or otherwise formed to the desired 
thickness and pattern of openings utilizing low stretch modulus materials 
made from any rubbery elastic material. Specifically unvulcanized 
thermoplastic compositions which are made of an elastomeric component and 
an optional compatible modifier which is a thermoplastic polymer of a 
relatively low molecular weight but solid at ambient temperatures have 
been found to make suitable elastic members for use in accordance with the 
present invention. 
Illustrative of the elastomeric components suitable for present purposes 
are block copolymers which comprise terminal thermoplastic polymer blocks 
and at least some non-terminal or intermediate elastomeric polymer blocks. 
Block copolymers of this general type may be prepared using a step-wise 
polymerization initiator; e.g., an organolithium compound. Such block 
polymerization techniques are well known in the art. 
The elastic component can be linear or radial A.sup.1 -B-A.sup.2 block 
copolymers or mixtures thereof with simple A.sup.1 -B block copolymers 
wherein A.sup.1 and A.sup.2 can be alike or different and represent a 
thermoplastic polymer block, such as poly (vinyl arene) block, and B 
represents an elastomeric polymer block such as a conjugated diene or a 
lower (i.e., C.sub.1 -C.sub.4) alkene. The modifier component is a low 
molecular weight thermoplastic polymer having an average molecular weight 
of about 500 to 7,500 and is present in the composition in an amount of 
about zero to about 200 parts by weight per 100 parts by weight of the 
elastomeric component. 
A preferred thermoplastic film composition for the elastic members 
comprises an elastomeric component which contains, as a major constituent 
thereof, an unvulcanized linear block copolymer of the general 
configuration, 
EQU A.sup.1 --B--A.sup.2 
wherein A.sup.1, A.sup.2 and B have the same meaning as hereinabove. In 
these block copolymers, the A-blocks are derived from styrene or styrene 
homologues, and the B-blocks are derived from conjugated dienes or lower 
alkenes. The thermoplastic polymer modifier is compatible with the 
elastomeric component and associates principally with the thermoplastic 
terminal blocks of the aforesaid unvulcanized block copolymer. The 
thermoplastic polymer modifier preferably has an average molecular weight 
of about 1000 to about 3000, and is present in the film composition in an 
amount of about 80 to 200 parts by weight per 100 parts by weight of the 
elastomeric component. 
The preferred A.sup.1 -B-A.sup.2 block copolymers have A-blocks derived; 
i.e., polymerized or copolymerized, from styrene or styrene homologues; 
and B-blocks derived from conjugated dienes, such as isoprene or 
butadiene, or from lower alkenes such as ethylene and butylene. Small 
proportions of other monomers also may enter into the block copolymers 
themselves. The individual A-blocks can have an average molecular weight 
of at least about 6000, preferably in the range of about 8000-30,000, and 
the A-blocks constitute about 5-50 percent, preferably about 10-30 
percent, by weight of the block copolymer. The average molecular weight of 
the B-blocks for linear A.sup.1 -B-A.sup.2 block copolymers preferably is 
in the range of about 45,000-180,000 and that of the linear copolymer, 
itself, preferably is in the range of about 75,000-200,000. The average 
molecular weight of the radial A.sup.1 -B-A.sup.2 block copolymers 
preferably is in the range of about 125,000-400,000. The term "linear 
block copolymer" (or copolymers) includes branched A.sup.1 -B-A.sup.2 
copolymers as well as unbranched A.sup.1 -B-A.sup.2 copolymers. The radial 
A.sup.1 -B-A.sup.2 copolymers useful for manufacture of elastic members 
for diapers of this invention are of the type described in U.S. Pat. No. 
3,281,383 to Zelinski, et al. and conform to the following general 
formula: (A-B-.sub.n -X), wherein A is a thermoplastic block polymerized 
from styrene or styrene homologues, B is an elastomeric block derived from 
conjugated dienes or lower alkenes, as indicated above, X is an organic or 
inorganic connecting molecule, with a functionality of about two to four 
as described in U.S. Pat. No. 3,281,383, or possibly with a higher 
functionality as described in the Article entitled "New Rubber Is Backed 
By Stars" appearing on Page 35 of the June 11, 1975, issue of Chemical 
Week. As used hereinabove, "n" has a value corresponding to the 
functionality of X. 
The preferred elastic member is highly thermoplastic and, though 
elastomeric, is unlike rubber in that it exhibits a relatively sharp 
melting point and is capable of being heat shaped. Also, the elastic 
member can form permanent heat seals to substrates such as non-woven 
fabrics or the like, at relatively low heat sealing temperatures, 
generally not above about 350.degree. F. The member is very flexible, 
extensive and soft, and normally exhibits a Gurley stiffness of about one 
or less at a film thickness of one mil. 
Elastic members especially suitable for use in disposable diapers may be 
made from combinations of thermoplastic rubber and amorphous 
polypropylene. The thermoplastic rubbers used in such combinations are 
block copolymers having blocks of polybutadiene or polyisoprene, and 
blocks of polystyrene. A review article discussing these materials is 
"Structure And Properties Of Block Polymers And Multi-phase Polymer 
Systems: An Overview of Present Status And Future Potential", by S. L. 
Aggarwal, Polymer, Vol. 17, November 1976, Pages 938-956. Two 
representative types of thermoplastic rubbers useful in these combinations 
are the linear block copolymers (A-B-A) having a mid-block of 
polybutadiene or polyisoprene and end-blocks of polystyrene, and the 
"star" or "radial" block copolymers having from 4 to 20 "arms" connected 
to a common center. Each arm is an A-B block copolymer, the inner portion 
being polybutadiene or polyisoprene, with the outer portion being 
polystyrene. 
The material added or combined with the thermoplastic rubber, primarily to 
improve process ability, while still retaining the characteristic rubbery 
properties of the rubber, is amorphous polypropylene. Amorphous 
polypropylene is a known material. It is essentially atactic polypropylene 
having an isotactic content of not more than about 20 weight percent, and 
preferably not more than about 10 weight percent. 
The amorphous polypropylene is employed in an amount sufficient to improve 
the processability of the thermoplastic rubber when extruding thin films 
or sheets. The exact minimum amount of amorphous polypropylene which must 
be employed varies somewhat for case to case, but it is usually of the 
order of about 10 weight percent, based on weight or rubber plus amorphous 
polypropylene, although the proportion may be as low as about 5 weight 
percent (on the same basis) in some cases. The upper limit of 
polypropylene will also vary from case to case, depending on the nature of 
the ingredients and the use intended for the product. At proportions above 
about 35 weight percent (on the same basis), a significant reduction in 
the characteristic rubbery elastomeric properties of the product begins to 
occur. This may be acceptable for some uses, and not for others. Thus, the 
upper limit of amorphous polypropylene would be that point at which the 
product still retains significant rubbery elastomeric characteristics. 
Other conventional materials, employed in the usual amounts, can be 
employed in the mixture for their known purposes. Such materials include 
pigments, anti-blocking agents, stabilizers, anti-oxidants, ultraviolet 
stabilizers, bonding aid, and the like. 
In some embodiments of the disposable diaper of the present invention, the 
elastic member is a member which may be made elastic by imparting heat or 
other forms of energy to the member to shrink the member and provide it 
with elastic characteristics. 
The heat shrinkable films which may be used as elastic members in the 
disposable diapers of the present invention may be the polyolefin films 
which have been oriented to a degree and which will then become elastic 
when heat shrunk. Usually, a preferred technique for orienting the 
polyethylene film to provide the heat shrunk elastic properties is by 
irradiation such as suggested in British Pat. No. 866,820. Also, useful as 
the heat shrunk elastic members are the copolymers of ethylene and vinyl 
acetate, ethylene and ethyl acrylate, and the like. The forming of such 
copolymers is well known and specific methods of forming such materials 
are disclosed in U.S. Pat. Nos. 2,200,429 and 2,953,551. After the 
copolymer is formed and made into a film, it is given the proper 
orientation as described in the previously mentioned British Pat. No. 
866,820. 
The elastic member useful in accordance with the present invention may also 
be made from other materials; such as, natural rubber, the synthetic 
rubbers, and the like. 
Broadly, the elastic members may be made from materials having elongations 
of from 20 to 1000 percent and preferably from about 50 to 500 percent 
with recoveries in the range of 20 to 100 percent and preferably from 70 
to 100 percent. The material should have a force to stretch it 100 percent 
of from 30 to 2000 grams. 
The important factor to remember is that when the material is placed in the 
end product, the material be elastic, as previously defined, so it 
functions as such an elastic in the final product. For example, in the 
diaper leg band area, the member should have 90 percent or better recovery 
in very short periods of time and preferably almost instantaneously, the 
member should also require a relatively low amount of force to stretch the 
leg band area back to its original or non-gathered length. Such force 
should be less than 200 grams and may be as low as 20 grams. 
FIG. 9 illustrates a disposable undergarment 160 suitable for use in toilet 
training infants, or by incontinent children or adults. The undergarment 
has a front portion 161, a rear portion 162, and a crotch portion 163 
comprised of an intermediate liquid absorbent panel 164 disposed between 
outer layer 165 and a moisture-permeable inner layer 166. The waistband of 
the undergarment may be gathered by an elastic member 167 located between 
the ends of the inner and outer layers at the rear portion and optionally 
between the ends of the inner and outer layers at the front portion. The 
undergarment may also be provided with elastic members 168 disposed 
between the inner and outer layers at the side margins of the crotch 
region. 
FIG. 10 illustrates the disposable undergarment 160 of FIG. 9 about a 
wearer in use; both side margins 169 and 170 of the front portion being 
joined to respective side margins 171 and 172 of the rear portion to 
define a waist portion 173 and self-fitting leg apertures 174. 
Several different types of facing materials may be used for the disposable 
undergarment, for example, the facing may be a non-woven web made of a 
mixture of fibers consisting predominantly of inexpensive, short, 
cellulosic fibers such as short wood pulp fibers or cotton linters in 
amounts of 75 percent to 98 percent, the balance being textile length 
fibers such as rayon as described in U.S. Pat. No. 3,663,348 to Liloia, et 
al. 
Non-woven facing materials suitable for use in disposable undergarments of 
this invention can have fabric weights in the range of from about 0.5 to 5 
ounces per square yard and densities of less than 0.15 g/cc., generally in 
the range of 0.05 to about 0.1 g/cc. The dry strength of the facing sheet 
for a fabric having a weight of about 1.5 ounces per square yard is at 
least 0.15 lbs. per inch of width in the machine direction and at least 
0.1 lb. per inch of width in the cross direction. Such fabrics have good 
elongation, loft, softness, and drape characteristics. Facings may also be 
made of an apertured non-woven fabric which is formed, for example, in 
accordance with the teachings of commonly assigned U.S. Pat. Nos. 
2,862,251; 3,081,514; and 3,081,515. Furthermore, facings may also be made 
from other types of fabric such as those disclosed and described in U.S. 
Pat. No. 3,485,706 to Evans. Such facings can be made of naturally 
occurring fibers, synthetic fibers or blends thereof. Typical facing 
sheets made of polyester type fibers may have a weight of about 0.75 
ounces per square yard. 
The facing may be the same size as, and coterminous with, the backing; or 
alternatively, the facing may be wider than the backing and have its side 
edges inwardly folded so that the facing is coterminous with the backing, 
as is shown in FIG. 3 of U.S. Pat. No. 3,612,055. In the latter case, the 
elastic members may be secured above the inwardly folded side edges of the 
facing. In addition, facings may be made from non-apertured materials such 
as non-woven isotropic webs or apertured polyolefin or polyester films 
having the desired moisture permeability. In all of the aforementioned 
facings, the materials should be relatively hydrophobic so as to retard 
wicking within the facing. 
The moisture absorbent batt or panel of a desired shape, but smaller than 
the facing and backing, can be formed in accordance with the teachings of 
U.S. Pat. No. 3,612,055 to Mesek, et al. 
A suitable backing material for the disposable undergarments embodying the 
present invention can be an opaque polyolefin; for example, polyethylene 
about 0.001 inch thick. Another suitable material for this purpose is 
polyethylene terephthalate having a thickness of about 0.005 inch. 
In use, the disposable diaper is applied to the baby by laying out the 
diaper on a single flat surface and placing the baby thereon. The waist 
underlying end of the diaper is that end having the fastener means and the 
other end of the diaper extends downwardly between the baby's legs. Next, 
the downwardly extending edge of the diaper is brought up between the 
baby's legs to a position covering the perineum and contiguous with the 
front portion of the baby's waist. The diaper thereafter is secured to the 
baby by placing the corners of the waist portion of the abdomen covering 
end as far around the baby's waist as they will go and by bringing the 
corners of the underlying end of the diaper into an overlapping 
relationship with the aforementioned corners so that the diaper snugly 
encircles the baby's waist and provides a custom fit. The adhesive tape 
fasteners are then prepared for use and the diaper is brought in a desired 
position by simply urging the pressure-sensitive adhesive surface of the 
tape tab in contact with the adjacent outer surfaces of the opposite 
corner of the diaper. 
In some instances, it may be desirable to have a second fastener available 
that can be applied just above the thigh of the infant and below the 
standard fastener to improve and secure the fit of the stretch diaper. 
A technique that may be used in the manufacture of the diaper in accordance 
with the present invention is to apply the adhesive to that portion of the 
backing or facing layer to which the elastic member is to be secured. In 
assembling the diaper, pressure is applied to the diaper in the region of 
the elastic member to adhere the facing and backing together between the 
apertures in the elastic member. 
Broadly, the method of manufacturing the elastic structure of the present 
invention comprises feeding the novel elastic member in a stretched 
condition between a pair of web surfaces. One of the web surfaces carries 
an adhesive. The laminate is pressed together and the web surfaces secured 
to each other through the apertures in the elastic member. The elastic 
member is then severed and portions allowed to relax. 
Referring to FIGS. 11 and 12 of the drawings, there is depicted, in a 
simplified representation, one method for assembling the components of a 
disposable diaper in accordance with the present invention. In this 
embodiment, the backing layer 180, absorbent pad 181 and facing layer 182 
are brought together. Just prior to combining the backing and facing 
layers a pair of elastic members 183 and 184 in accordance with the 
present invention are inserted along the longitudinal side margins of the 
backing and facing layers. The elastic members are stretched prior to 
being combined by running the nip rollers 185 and 186 at a speed slower 
than that of compressing rollers 187 and 188. Lines of adhesive are 
applied to the backing layer by nozzles 189. At least one of these lines 
of adhesive underlie each elastic member. Pressure is applied to the 
diaper assembly in the region of the elastic members, by passing those 
regions through the nip of compressing rollers 187 and 188. It is 
preferred that the surface of one of the rollers be resilient to aid in 
urging the facing and backing layers into contact with each other between 
the apertures in the elastic member and assist in securing the facing and 
backing together through these apertures. The diaper assembly is conveyed 
to a rotating vacuum cylinder 190 which carries approximately spaced 
anvils 191 on its surface. The anvils are spaced from each other a 
distance equal to the desired diaper length. A knife 192 severs individual 
diapers 193. On severing the diapers, the elastic members are severed in 
portions wherein the longitudinally extending elastic elements are not 
transversely connected. The individual diapers are then conveyed away and 
packaged as is well known. 
The foregoing description of the drawings are illustrative and are not to 
be taken as limiting. Still other variations and modifications are 
possible without departing from the spirit and scope of the present 
invention.