Field of the Invention:
The present invention generally relates to inflatable articles formed
of a laminate that is gas impermeable and elastically deformable, and particularly
relates to a laminate used in forming a buoyancy compensator vest that is more
comfortable to the user due to an ability to use lower inflation pressures.
Background of the Invention:
Divers usually wear jackets, or vests, to achieve neutral or slightly
positive buoyancy at various depths. The vest typically includes a buoyancy compensator
chamber which the diver can selectively pressurize from the diver's air tank in
order to adjust buoyancy under water. The buoyancy compensator normally also has
an associated pressure relief valve.
Various diving vests with buoyancy compensators are known, such as
described by U.S. Patent 4,016,616, issued April 12, 1977, inventor Walters; U.S.
Patent 4,561,853, issued December 31, 1985, inventors Faulconer and Langton. However,
previous buoyancy compensator devices have tended to be tight, highly inflated
in use, and rather uncomfortable, particularly because during exposure to wave
impact air is forced out of the associated relief valve which usually means that
the chambers are typically inflated to a high pressure level.
One approach to increasing diver comfort has been to provide a soft
backpack with a liquid-filled bladder that can be secured to a buoyancy compensator,
such as is described by U.S. Patent 4,952,095, issued August 28, 1990, inventor
Walters. Another approach (a life jacket design) is described by U.K. patent Application
8725209, published May 25, 1988, in which relatively flat inflatable panels are
However, diver comfort remains an objective for which improvements
continue to be sought for diving applications.
Materials for making diving suits are known for example from DE-A-1
506 338 and GB-A-2 021 040. In the former document the laminate material comprises
an impermeable, elastic sheet of neoprene rubber adhered to an elastomeric fabric
(eg. cellular polyurethane or polyester), while the laminate material of the latter
document comprises a permeable central core layer of elastomeric fabric sandwiched
between two layers of rubber.
Further known laminate materials, for use in making upholstered furniture
and shoe uppers are known for instance from US-A-3 948 702 and US-A-4 229 472.
Summary of the Invention:
Accordingly, it is one object of the present invention to provide
a laminate that is substantially gas impermeable and elastically deformable and
that can be formed into a wide variety of inflatable articles having different
stretch and strength needs, Particularly relatively high pressure inflatables having
good cycle life.
In one aspect of the present invention, an article comprises a laminate
that includes an elastomer layer capable of repeated stretch and retraction. Opposed
to the elastomer layer is a first substantially gas impermeable layer which is
a continuous polymeric film at least 0.0635 mm (2.5 mil) thick, and the two layers
are substantially continuously adhered to one another and maintained in laminated
form by adhesive means.
In a particularly preferred embodiment of the inventive article,
the laminate forms an elastically deformable surface for receiving and containing
gas therein, such as buoyancy gas as part of a SCUBA diver's vest, a dry suit
or a semi-dry suit. Other embodiments for the inventive laminates include various
inflatable articles, such as rafts and kayaks, automobile safety bags, diving
suits, swimming learning vests, aircraft and life saving jackets and vests, medical
therapeutic containers, waders, and the like.
Brief Description of the Drawings:
Detailed Description of the Preferred Embodiments:
- Figure 1 illustrates, in cross-section, a laminate embodiment of the invention;
- Figure 2 is a perspective of a buoyancy compensator with which the inventive
laminate is useful; and
- Figure 3 is a sectional view in the direction of lines 3-3 of Fig. 2 showing
a chamber for containing buoyancy compensating gas.
Laminates of this invention include an elastomer layer, a substantially
gas impermeable layer, and adhesive means for adhering the layers to one another,
and can be used to form all or part of a wide variety of articles. With reference
to Fig. 1, a laminate embodiment 10 is illustrated with elastomer layer 12, first
opposed substantially gas impermeable layer 14, and adhesive means 16 for substantially
continuously adhering layers 12, 14 to one another and to form a substantially
gas impermeable and elastically deformable surface (actually, two surfaces illustrated
as surface 18a and surface 18b). Adhesive means 16 is also for maintaining layers
12, 14 in laminated form when the laminate is repeatedly stretched, such as during
Suitable elastomers for forming elastomer layer 12 include materials
formed by elastomeric fibers, such as spandex fibers, in woven, non-woven, or knit
fabrics, which can further include one or more of materials such as nylon and
polyester or ether based polyester.
Preferred fibers are selected from the group consisting of polyester
elastomers, polyester/polyether elastomers, polyamide/polyester/polyether elastomers,
polyester/polyurethane elastomers, polytetramethylene terephthalate and polyester/polyurethane
elastomers. More preferably, the fibers are polyester/polyether elastomers. Preferred
polyester/polyether elastomers are described in U.S. Patents 3,763,109, 3,766,146,
and 3,651,014. Polyester/polyether elastomers and polyester/polyurethane elastomers
are available commercially from E. I. du Pont de Nemours and Company under the
trademarks Hytrel and Lycra.
A particularly preferred material for elastomeric layer 12 is polyester.
Among the various suitable commercially available materials that may be used as
elastomer layer 12 are, for example, stretchable Nomex fabric available from du
Pont and Antron Cordura mixed with spandex fibers ("Spandura"), also available
from du Pont. Fabric weight may vary, depending upon particular applications,
with a preferred fabric weight range being on the order of about 93 to about 775
(about three ounces to about twenty-five ounces per square yard),
and particularly preferred being about 77.5 to about 496 g/m2
two and one-half ounces to about sixteen ounces per square yard) for forming components
of SCUBA diving apparatus, such as a buoyancy compensator.
The first opposed substantially gas impermeable layer 14 is a continuous
polymeric film. Gas transmission properties are generally a function of film thickness,
with films of about 0.0127 mm (0.5 mils) PET (polyethylene terephthalate), for
example, typically having an oxygen transmission of about 1.085 cm3/100
cm2/day (7 cc/100 in2/day). Because the film should be substantially
gas impermeable in forming the inventive laminate, the film thickness is at least
0.0635 mm (2.5 mils), with preferred thicknesses typically being between about
0.1778 mm (7 mils) to about 0.762 mm (30 mils), more preferably about 0.1778 mm
(7 mils) to about 0.4064 mm (16 mils). Such films are flexible, yet provide substantial
strengths in preparing inventive laminates.
Also, films with reduced permeability to vapors (that is, films that
are substantially gas impermeable for a variety of applications contemplated by
this invention) can themselves be composites, such as where one layer is a flexible
polymer, such as a polyurethane, polyethylene, ether polyurethane, or polypropylene,
while another layer is coated on or coextruded and serves as a barrier layer. Barrier
layers can generally be viewed as substantially organic based or substantially
inorganic based. For example, U.S. Patent 3,442,686, issued May 6, 1969, describes
a film composite in which silicon oxide coatings are deposited on polymers to
serve as a barrier layer. This produces barrier coatings on even quite thin polymer
films of oxygen transmission rate properties on the order of about 0.031 cm3/100
cm2/day (0.2 cc/100 in2/day) and similar water vapor transmission
The layers 12 and 14 are bonded, or continuously adhered, and maintained
in laminated form (that is, do not delaminate) even when the laminate is repeatedly
stretched and retracts, such as to accommodate substantial volume increases due
to elastic deformations in response to elevated pressures. Thus, the laminate
has a good elastic limit for the various applications contemplated without permanent
The substantially gas impermeable layer, as has been described, will
tend to also have some stretchability, but it is believed to be the elastomer
layer that primarily provides the necessary, preferably two-dimensional, stretch
and the essential retraction properties so that the inventive laminate can be
repeatedly stretched and retract following elastic deformations in use due to elevated
pressures. The particular strength and amount of stretchability desired will depend
upon the particular application. However, in forming buoyancy compensators one
normally encounters elevated pressures in the range of about 3447 to about 55158
(about 0.5 psi to about 8 psi), which can be readily accommodated
by a laminate in accordance with this invention.
The adhesive means, or adhesive layer, 16 continuously adheres layers
12, 14 such as by melt bonding or by adhesive bonding, for example by thermal
lamination on hot rolled calendaring equipment. Suitable adhesive materials are
commercially available, for example, from laminators or combiners, such as Kenyon
Laminating Group (Peacedale, Rhode Island) and Uretek (New Haven, Connecticut).
A particularly preferred inventive laminate is formed of 100% polyester tubular
knit with adhesive from Polyurethane Specialties Co. (Lindhurst, New Jersey) through
Kenyon Laminating Group, using a 0.254 mm (10 mil) thick polyurethane ether based
film. An adhesive with good resistance to UV, salt water, and within a preferred
range of modulus (stretch) between 6,000-10,000 is Uretek, style # nylon 16-71.
Particularly preferred adhesive materials for adhesive bonding are
liquid polyether urethanes (which can be dissolved in methyl ethyl ketone). For
example, such an adhesive material can be substantially continuously spread on
film layer 14 and thereafter elastomeric fabric 12 added and adhered in a heat
calendar process. Application can be by known techniques, such as by reverse roll
head, by floating head, or by knife over roll head. The latter is particularly
preferred. The depth at which a solubilized adhesive, such as an ether based polyurethane
dissolved in MEK, penetrates the layer to which it is applied is controllable by
the time when cure is commenced. The resultant laminates are preferably RF weldable
for preparation in a variety of forms.
Where even greater strength is required for a particular application,
then a second layer (not illustrated), also preferably gas impermeable and also
preferably polymeric, may be added so that one of the first layer and second layers
is sandwiched between the elastomer layer and the other of the first and second
layers. This second layer is preferably adhered in the sandwiched relationship
by the same or a different adhesive process as is the first layer. For example,
adhesive material 16 can be a solvent based adhesive while the second layer can
be calendar heat bonded (that is, fused) to film 14.
In the various applications for the inventive laminate 10, either
surface 18a or surface 18b can be exposed to the elevated pressure for inflation,
although the polymeric layer will typically be exposed to the elevated pressure
while the elastomeric layer (defining surface 18a) will be exposed to touch or
be adjacent to a wearer's skin for purposes of comfort.
Turning to Fig. 2, a buoyancy compensator 20 is illustrated having
opposed walls 22, 24 and with which the inventive laminate is usefully employed.
For example, either all or part of wall 22 or all or part of opposed wall 24 can
be made from inventive laminate 10.
With reference to Fig. 3, both walls 22, 24 are illustrated as formed
from inventive laminate 10 where buoyancy compensator 20 is illustrated as being
formed with chamber 25 between the two walls 22, 24. Thus, as illustrated, the
buoyancy compensator 20 can be of a single bag construction. In addition, the buoyancy
compensator 20 can be of the type (not illustrated) well known to the art by having
a double bag, or double wall, where the outer bag generally provides for the maintenance
of pressure within the buoyancy compensator while the inner bag, or bladder, provides
a maintenance of the air therein in a sealed relationship.
As already noted, either all or part of wall 22 or all or part of
opposed wall 24 can be made from inventive laminate 10. In one particularly preferred
embodiment, wall 24, which is in contact with the diver's body, is not made from
the inventive laminate 10, but rather is made from a soft, strong 100% polyester
with a suede-like finish, while the opposed wall 22 is formed from inventive laminate
10. The walls 22, 24 are preferably affixed one to the other to form a chamber
for receiving pressurized air, but affixation can also be by various heat sealable
processes (such as tape and glue or a vulcanizing hand process).
The buoyancy compensator 20 typically has a waist portion 26, which
terminates in attachable belt portion 28. The belt 28 has buckles 30 and 32 (or
other fastening means) in order to secure the waist portion 26 around a user's
waist. Waist portion 26 will preferably be formed of a woven neoprene in combination
with a nylon stretch material, which has neutral buoyancy in water. This material
is also preferably used for the shoulder portions 34, 36.
Shoulder portions 34 and 36 define a neck area 38. A harness 40 (illustrated
generally at the back) is constructed to receive a backpack (not illustrated)
which snugly fits in harness 40 to provide lumbar support and to cradle the SCUBA
air tank 50. The air tank 50 has a valve and a regulator, generally shown as valve
and regulator 52. The valve and regulator 52 serve to provide breathing gas to
the diver wearing buoyancy compensator 20.
Tube 56 is connected to an inflation system 58. The inflation system
58 has a mouthpiece 62 through which a user can inflate the buoyancy compensator
orally. Inflation system 58 may comprise a soft-touch power inflator 64, oral
inflation button 65, a rapid exhaust valve 66, and an overpressure relief valve
68 which all work together as inflation system 58 and which are preferably surrounded
in a protective material, such as a soft elastomer, that conforms to the user's
hand and protects the mechanical parts from wear and tear. The soft touch inflator
64 permits control of the air entering the buoyancy compensator 20, while the rapid
exhaust valve 66 is readily opened by pulling down on the inflator tube 56. The
overpressure relief valve 68 is preferably integrated into the inflation system
58 to allow air to escape quickly in the event of overpressuring the buoyancy
Because the inventive laminate 10 is elastically deformable, the
portions of such a buoyancy compensator 20 formed from the inventive laminate are
more comfortable to the user due to an ability to use lower inflation pressures,
particularly because during exposure to wave impact the elastically deformable
surface (such as surface 18a and surface 18b) will tend to deform and the garment
itself does not need to be inflated to the typical high pressure levels to compensate
for wave action. That is, the deformability feature allows larger wave impact without
losing air from a chamber formed by the inventive laminate. This results in a
substantially more comfortable garment and the uncomfortable "squeeze" sensation
of highly inflated prior art buoyancy compensators is avoided.
Particularly preferred inventive laminate constructions permit volume
increases due to elastic deformation on the order of up to about 100 percent in
response to elevated pressures, such as within the range of about 2068 to about
(about 0.3 psi to about 5 psi). As will be appreciated, chambers
formed by the inventive laminates 10 will be resistant not just to elevated pressures,
but more generally will perform as a substantially gas impermeable membrane for
pressure difference with respect to the pressures imposed on surfaces 18a, 18b.
That is, laminate 10 is substantially gas impermeable even with the pressure difference
between a hypothetical pressure Pa (to which surface 18a would be exposed)
and a hypothetical pressure Pb (to which surface 18b would be exposed).
Thus, inventive laminate 10 could be used to form part or all of a diving suit
where the internal suit pressure and the external pressure due to water are adjusted
to neutral buoyancy over a pressure difference range beginning at about 0 N/m2
and upwards. Cycle tests with different laminates suggest upper pressure difference
values to about 689476 N/m2
(100 psi) can be accommodated. Where the
inventive laminate 10 is forming a membrane between fluids with one fluid in liquid
or solid form, then the elastically deformable surface of the laminate can have
a volume variable in response to variable fluid densities, such as in medical therapeutic
containers where expansion can be due to a liquid-to-solid transformation.
Again with reference to Fig. 1, typical and preferred aspects of
buoyancy compensator 20 include shoulder areas 34 and 36 that are adjustable by
means such as buckles 80 and 82 on adjustment straps. The shoulder areas 34,36,
as well as pockets and soft backpack, can be RF welded to save labor cost of sewing
with the new laminate 10. Additional attachments, fasteners, and the like features
as are well known to the art may be included with the buoyancy compensator 20.
For example, hooks, straps, loops, buckles, and the like are usefully included
(but not illustrated).
The walls 22 and 24 are shown with a sealed periphery 84. As earlier
noted with reference to Fig. 3, this seals the outer edges to form an interior
chamber between the walls 22 and 24. Buoyancy compensators of the invention can
have a plurality of chambers, preferably where such chambers are interconnected
and thus at the same pressure.
Returning to Fig. 2, heatset areas 86 can take a variety of forms,
shapes, and locations on the article and can be provided by radio frequency (RF)
welding, ultrasonic welding, thermal heatsealing, or any other suitable sealing
process, so that the buoyancy compensator walls 22 and 24 are brought into connection
with each other at desired areas of the article to better fit or conform to a
user's shape, to accommodate attachments, and the like. Also, the conformation
of the buoyancy compensator is retained by the various heatset areas to prevent
undue expansion during dives.
As will be readily understood, the inventive laminate 10 can be desirably
utilized in preparing other articles, particularly other inflatable articles, such
as rafts and kayaks, automobile safety bags, diving suits, swimming learning vests,
aircraft and lifesaving jackets and vests, medical therapeutic containers, waders,
and the like. Other buoyancy compensator vests are also known to the art, such
as snorkel buoyancy compensators, for which inventive laminate 10 is readily and
Aspects of the invention will now be further illustrated.
Testing was performed on various laminate 10 embodiments of the invention.
Cycle testing was performed by forming laminate 10 embodiments into pressurized
air containing chambers (such as illustrated by Fig. 3), and then repeatedly filling
and evacuating the chambers with pressures by a machine that can fill to 137895
N/m2 (20 psi) and can evacuate to subatmospheric. An overpressure valve
permits positive pressure variations up to 689476 N/m2 (100 psi).
Chambers formed from various laminates were initially screened, and then selected
laminates were tested at over 10,000 cycles of input (10342 N/m2
psi)) and exhaust.
A burst test was also used in which pressurized air was input into
the chambers up to rupture. Laminates were further subjected to a wash test in
which 10 cm by 10 cm (four inch by four inch) laminate pieces were subjected
to heavy cycle, standard washing machine washing for 50, 100, or 150 cycles and
then examined for wear, possible delamination, and color degradations. Ten out
of fifty cycles included bleach, and about one-third of the cycles were with hot
water, another about one-third with warm water, and a final about one-third with
cold water. All cycles included conventional laundry detergent at manufacturers'
suggested use levels.
Laminates were yet further subjected to impact tests where a drop
weight plate machine with a 6.8 Kg (fifteen pound) drop weight was used to impact
the laminate rapidly and to apply uneven stress to different local areas on chambers
formed from the laminates. The laminate forming chambers were then visually inspected
for any weaknesses due to the impact tests.
Preferred laminates of this invention perform well under the just
described cycle, burst, wash, and impact testing. Several preferred laminate 10
embodiments of the invention, all successfully passing the tests as above described,
were prepared as follows.
A laminate embodiment was prepared from 100% knit polyester (style
5270, commercially available from Flynt Amtex, Inc.) weighing 120.9 g/m2
ounces per square yard), and having a 75% stretchability (both length and width).
Adhesive used was obtained from Polyurethane Specialties Co. through Kenyon Laminating
Group. The substantially gas impermeable layer was 0.254 mm (10 mils) polyurethane
film. The polyester knit and polyurethane film were laminated by means of the
adhesive through a heat calendar process, and the resulting laminate gave excellent
A second laminate embodiment giving good testing results was formed
in a similar manner with a nylon and spandex fabric (170 g (6 oz), 120 warp,
and 80 fill) and either 0.1778 mm (7 mils) or 0.4064 mm (16 mils) polyurethane
Yet another laminate embodiment with good test results used Antron
Cordura and spandex (198 g (7 oz), 120 warp, and 95 fill) as the elastomer layer,
while the first substantially gas impermeable layer was 0.254 mm (10 mils) polymeric
film with a second layer being sandwiched between the elastomer layer and first
layer by means of adhesive. The second, sandwiched layer was a stretchable (spandex
knit) ballistic type fabric (such as used in bullet-proof vests).
A fourth embodiment was prepared where the inventive laminate was
formed from 100% stretch polyester as elastomer and adhered to 0.254 mm (10 mils)
polyurethane film. This laminate was then used to form one wall of a chamber while
the other wall was formed from a 0.254 mm (10 mil) polyurethane film adhered to
a non-stretch polyester suede. The two walls were joined into the pressurized
air containing chamber by means of a welded joints.