A laminate consists of two layers of non-woven elastic foam enclosing a non-elastic scrim formed by treating all of the materials with a latex solution, combining the materials under pressure while the two layers of elastic foam are in stretched condition, allowing the material to retract and slitting the material lengthwise into bandage material.

This invention relates to an expandable laminate material that is suitable 
for various applications, but is particularly directed toward an improved 
bandage material for use in the veterinarian and human fields of medicine. 
Many forms of stretchable material have been devised for use in bandages 
and other applications. Corrugated or shirred fabrics have been known for 
many years and have found increasing acceptance in recent times. Many such 
fabrics are formed by bonding two layers to opposite sides of stretched 
rubber yarns and then allowing the material to retract causing a puckering 
or gathering of the material. Another type of material, for example as 
described in U.S. Pat. No. 3,575,782 to Hanson, issued Apr. 20, 1971, is 
formed from a series of spaced parallel elastic yarns bonded, while 
stretched, to two exterior layers of non-woven web material. Such material 
has found extensive use in bandages because the bandage may be stretched 
while applying to the elastic limits of the yarns to apply continuing 
pressure to the bandaged area. 
Another material that also finds application in bandages is described in 
U.S. Pat. No. 3,842,832 to Wideman, issued Oct. 22, 1974, in which an 
inner layer of cellular foamed plastic material is bonded between layers 
of non-woven fabric material while the inner layer is under tension. 
These and other bandage materials represented a substantial improvement 
over earlier cloth bandages, and the present invention represents a 
substantial improvement over the stretch bandages heretofore in use. 
It is thus an object of this invention to provide an improved elastic 
laminate particularly suitable for use in bandages for both human and 
animal use. 
It is a further object of the invention to provide such an improved 
laminate that is self-adhering and porous. 
It is another object to provide a bandage formed from such a laminate with 
improved tear strength in the longitudinal direction of the bandage. 
It is yet another object of the invention to provide such a bandage having 
a finite limit of stretch in the longitudinal direction, so that failures 
caused by overstretching are eliminated, and having minimal stretch and 
necking down in the transverse direction. 
It is another object to provide an improved method of making such a bandage 
that results in lower costs and improved quality.

Before assembling the bandage, it is preferred that the three layers of 
material be treated with latex and dried. FIG. 1 illustrates the method of 
applying the coating. Polyester foam sheet material 2 from a roll 4 is 
arranged to be passed through a bath 6 of latex solution, through a pair 
of wringer rolls 8, and through a drying oven 10, after which it is 
rewound into a roll 12. 
The polyester foam material 2 is preferably an open cell structure with 40 
to 45 cells per linear inch and having thickness of about 0.03 in. Such a 
foam material is available from Tenneco, Inc., Paramus, N.J., and from 
other sources. The material is passed over a guide roller 14 into the bath 
6 and under two rollers 16 and 18 that are submerged in a latex solution 
20. The latex solution is formed at 80 percent natural latex and 20 
percent synthetic latex. Material sold by Glennon-American Inc., 40 School 
Street, Middleton, Mass., as #1799 latex saturant is satisfactory for this 
purpose. The wringer rolls 8a and 8b, which are preferably positioned so 
that as excess latex solution is squeezed from the foam it returns to the 
bath 6, are adjusted with sufficient pressure that the latex remaining on 
the foam is about 0.08 ounces of the latex solution per square yard of 
foam. The speed and pressure of the rolls should be adjusted to give the 
desired coating depending upon the characteristics of the particular latex 
solution being used and the characteristics of the foam. The foam then 
passes through a drying oven, which removes the water from the latex 
solution, and onto a supply roll 12. 
The central layer 22 of the bandage is formed of a non-elastic scrim, such 
as cheesecloth, which has perpendicular spaced yarns. I prefer that the 
material from which the cheesecloth is made be less absorbent than cotton 
and one that provides greater strength. Polyester cheesecloth with 20 
yarns per inch in each direction is suitable. Polypropylene netting with 
8.times.8 yarns per inch, such as is sold by Hercules Inc., Wilmington, 
Del. under the trademark "Delnet", is also a suitable material. For best 
results, the density of yarns extending in the machine direction 
(lengthwise), prior to the formation of the bandage, is greater than the 
density of the yarns that extend across the material. Preferably, the 
yarns running in the machine direction are from 8 to 28 per inch, and the 
cross yarns are between 4 and 20 per inch. The cheesecloth 22 also is 
treated with a latex solution. The method of applying the latex may be 
exactly the same as that described in connection with the foam except that 
the wringers 8 are adjusted so that the wet weight of latex remaining on 
the scrim after passing through the wringers and before drying is about 
0.60 ounces per square yard. 
In treating both the scrim and the foam with latex, it is preferred that 
the wet weight of the latex be equal to at least one-half the weight of 
the substrate and that it should not exceed the weight of the substrate. 
Proper choice of the latex used will result in a porous laminate which is 
desirable in bandages and for other uses. Where little or no porosity is 
desired, greater amounts of latex may be applied. 
To form the bandage, the polyester foam, indicated at 24a and 24b in FIG. 
2, which has been treated with the latex solution and dried, is fed from 
the supply roll 12 through a pair of nip rolls 26a and 26b and then 
between a pair of pressure rolls 28a and 28b. Another supply roll 12 of 
the treated polyester foam, as indicated at 24b, is fed through the a 
similar pair of nip rolls 26c and 26d and then between the pressure rolls 
28a and 28b. 
The scrim 22, which has been treated with the latex solution and dried, is 
fed from a supply roll into the pressure rolls 28a and 28b between the two 
layers 24a and 24b of foam. 
The foam material 24a and 24b is in stretched condition when it is 
laminated with the layer of scrim. This is accomplished by adjusting the 
relative speeds of the nip rolls and the pressure rolls. In this example, 
the nip rolls 26a and 26b have a peripheral speed equal to one third the 
peripheral speed of the pressure rolls 28a and 28b. The nip rolls 26c and 
26d are driven at the same speed as the rolls 26a and 26b. With this 
arrangement, the two pairs of nip rolls serve as brakes that hold back the 
foam material so that it is in stretched condition at the time it is 
pressed into a unit laminate with the scrim 22. As the laminated material, 
indicated at 32, leaves the pressure rolls 28a and 28b, the elastic foam 
retracts to approximately its original length, causing the scrim to pucker 
so that the completed bandage will have a slightly rough or crinkled 
appearance. The inner layer of scrim 22 of the material 32 when in the 
relaxed condition is puckered, by which is meant that the yarns in the 
direction the material moves through the rolls are crinkled forming a 
generally undulating, corrugated or ruffled pattern. When the material 32 
is stretched, for example to double or triple its original length, the 
inner layer reaches, at the full extension, its full length and 
effectively prevents further stretching of the material. The material 32 
is fed onto a roll 34 in preparation for the slitting operation. 
The slitting operation is indicated in FIG. 3. The roll 34 of bandage 
material is fed through an edge control mechanism 36, which positions one 
edge of the material, into a conventional slitter 38 equipped with spaced 
slitting knives 40 that cut the material 32 into individual bandages as 
indicated at 32a. Because of the elastic nature of the material, it is 
difficult to control accurately the width of the laminate during its 
manufacture and it is desirable therefore to fabricate the laminate in 
relatively wide widths to minimize waste when the laminate is slit. In 
addition, if the cross yarns are spaced closely together and it is 
attempted to slit near the edge of the material 32, the edge will have a 
ragged appearance. It is desirable therefore to leave as much as one-half 
inch of material as waste on each side. As a practical matter, a width of 
48 or 80 inches is desirable to minimize the waste produced by slitting. 
FIG. 4 shows a cross-section of the material 32 as it appears in a relaxed 
condition. The scrim material is readily confined between the layers of 
elastic foam 24a and 24b provided the cross yarns are close enough 
together. If too few cross yarns per inch are used, the cross yarns may 
penetrate the foam material to form individual loops extending above the 
surface of the bandage. If the scrim is formed of monofilament material, 
these loops cause the bandage to have an undesirably rough surface. In 
practice, the scrim should be selected with as low a number of cross yarns 
per inch as possible without producing an undesirably rough bandage. Fewer 
yarns per inch result in a smoother edge cut when the bandages are formed 
by slitting, particularly if the slit is made near an edge of the material 
32. 
When the bandage is stretched, the elastic foam is elongated and the 
puckers disappear from the scrim, as indicated in FIG. 5. When the bandage 
has been stretched to the point where the non-elastic scrim is fully 
extended, the bandage resists further extension, which can occur only if 
the scrim is torn. 
The finished bandage thus meets the most rigid requirements for both animal 
and human applications. The bandage may readily be fabricated to have a 
permitted stretch factor of 100%, and strength sufficient for any 
practical application. The strength is exhibited in both directions and 
the necking down is minimal even under the fully stretched condition. 
The bandage as described with three layers is both strong and durable and 
is suitable for the most demanding applications. A lighter and less 
durable bandage, having application in less demanding situations can be 
constructed with two layers of material. Thus, by eliminating the layer 
24b of elastic polymer and using only the elastic layer 24a and the layer 
22 of scrim, an acceptable bandage for limited applications can be 
fabricated. 
From the foregoing it will be apparent that the laminate embodying my 
invention is well adapted to meet the ends and objects set forth herein 
and is suitable for a wide variety of purposes in the form described here. 
It will be seen also that the characteristics of the laminate can be 
readily altered to best fit it for each particular application.