Nonwoven thermal insulating batts

A nonwoven thermal insulating batt is provided. The batt comprises structural staple fibers and bonding staple fibers, the fibers being entangled and substantially parallel to the faces of the batt at the face portions and substantially perpendicular to the faces of the batt in the central portion of the batt. The bonding staple fibers are bonded to the structural staple fibers and other bonding staple fibers at points of contact. Also provided is a method of making the nonwoven thermal insulating batt which comprises air-laying a web of structural staple fibers and bonding staple fibers with the fibers being entangled and substantially parallel to the faces of the web at the face portions and in an angled, layered configuration in the central portions of the web. The air-laid web is reconfigured such that the fibers in the central portion of the web are substantially parallel and perpendicular to the faces of the web and the fibers are bonded to stabilize the reconfigured web to form the nonwoven thermal insulating batt.

FIELD OF THE INVENTION 
This invention relates to insulating and cushioning structures made from 
synthetic fibrous materials and more particularly to thermal insulating 
materials having insulating performance comparable to down. 
BACKGROUND OF THE INVENTION 
A wide variety of natural and synthetic filling materials for thermal 
insulation applications, such as in outerwear, e.g., ski jackets and 
snowmobile suits, sleeping bags, and bedding, e.g., comforters and 
bedspreads, are known. 
Natural feather down has found wide acceptance for thermal insulation 
applications, primarily because of its outstanding weight efficiency and 
resilience. Properly fluffed and contained in an envelope to control 
migration within a garment, down is generally recognized as the insulation 
material of choice. However, down compacts and loses its insulating 
properties when it becomes wet and exhibits a rather unpleasant odor when 
exposed to moisture. Also a carefully controlled cleaning and drying 
process is required to restore the fluffiness and resultant thermal 
insulating properties to a garment in which the down has compacted. 
There have been numerous attempts to prepare synthetic fiber-based 
substitutes for down which would have equivalent thermal insulating 
performance without the moisture sensitivity of natural down. 
U.S. Pat. No. 3,892,909 (Miller) discloses fibrous bodies simulating 
natural bird down which include larger circular bodies, or figures of 
revolution, and smaller feather bodies, the feathery bodies tending to 
fill the voids formed by the larger circular bodies. The fibrous bodies 
are preferably formed from synthetic fiber tow. 
U.S Pat. No. 4,588,635 (Donovan) describes synthetic down thermal 
insulating materials which are batts of plied card-laps of a blend of 80 
to 95 weight percent of spun and drawn, crimped, staple, synthetic 
polymeric microfibers having a diameter of from 3 to 12 microns and 5 to 
20 weight percent of synthetic polymeric staple macrofibers having a 
diameter of from more than 12, up to 50 microns. Donovan describes this 
fiber blend as comparing favorably to down or mixtures of down with 
feathers as an insulator in that it will provide an equally efficient 
thermal barrier, be of equivalent density, possess similar compression 
properties, have improved wetting and drying characteristics, and have 
superior loft retention while wet. These batts are formed by physical 
entanglement of the fibers achieved during carding. An expanded discussion 
of these same materials can be found in Dent, Robin W. et al., DEVELOPMENT 
OF SYNTHETIC DOWN ALTERNATIVES, Technical Report Natick/TR-86/021L--Final 
Report, Phase 1. 
U.S. Pat. No. 4,392,903 (Endo et al.) discloses a thermal insulating bulky 
product which has a structural make-up of substantially continuous, single 
fine filaments of from about 0.01 to about 2 deniers which are stabilized 
in the product by a surface binder. Generally, the binder is a 
thermoplastic polymer such as polyvinyl alcohol or polyacrylic esters 
which is deposited on the filaments as a mist of minute particles of 
emulsion before accumulation of the filaments. 
U.S. Pat. No. 4,118,531 (Hauser) discloses a thermal insulating material 
which is a web of blended microfibers with crimped bulking fibers which 
are randomly and thoroughly intermixed and intertangled with the 
microfibers. The crimped bulking fibers are generally introduced into a 
stream of blown microfibers prior to their collection. This web combines 
high thermal resistance per unit of thickness and moderate weight. 
U.S. Pat. No. 4,418,103 (Tani et al.) discloses the preparation of a 
synthetic filling material composed of an assembly of crimped monofilament 
fibers having crimps located in mutually deviated phases, which fibers are 
bonded together at one end to achieve a high density portion, while the 
other ends of the fibers stay free. This fill material is described as 
having superior bulkiness and thermal insulation properties. This filling 
material is described as being suitable for filling a mattress, bed, pad, 
cushion pillow, stuffed doll, sofa, or the like, as well as being a down 
substitute suitable for filling jackets, sleeping bags, ski wear, and 
night gowns. 
U.S. Pat. No. 4,259,400 (Bolliand) discloses a fibrous padding material 
simulating natural down, the material being in the form of a central 
filiform core which is relatively dense and rigid and to which are bonded 
fibers which are oriented substantially transversely relative to this 
core, the fibers being entangled with one another so as to form a 
homogeneous thin web and being located on either side of the core, 
substantially in the same plane. 
U.S. Pat. No. 4,433,019 (Chumbley) discloses another approach to thermal 
insulating fabrics wherein staple fiber is needle-punched through a 
metallized polymeric film and through a nonwoven polyester sheet and the 
film and sheet are placed adjacent to each other such that the 
needle-punched fibers protrude from each face of the fabric to produce a 
soft, breathable fleece-like material. 
U.S. Pat. No. 4,065,599 (Nishiumi et al.) discloses down-like synthetic 
filler material comprising spherical objects made up of filamentary 
material with a denser concentration of filaments near the surface of the 
spherical object than the filament concentration spaced apart from the 
surface. 
U.S. Pat. No. 4,144,294 (Werthaiser et al.) discloses a substitute for 
natural down comprising sheets of garneted polyester which are separated 
into a plurality of small pieces, each of which pieces is generally formed 
into a rounded body. Each of the rounded bodies include a plurality of 
randomly oriented polyester fibers therein, and each of the rounded bodies 
provides a substantial resiliency to permanent deformation after the 
application of force to them. 
U.S. Pat. No. 4,618,531 (Marcus) discloses polyester fiberfill having 
spiral-crimp that is randomly arranged and entangled in the form of 
fiberballs with a minimum of hairs extending from their surface, and 
having a refluffable characteristic similar to that of down. 
U.S. Pat. No. 3,905,057 (Willis et al.) discloses a fiber-filled pillow 
wherein the fibrous pillow batt has substantially all its fiber oriented 
parallel to one another and perpendicular to a plane bisecting a vertical 
cross-section of the pillow. A pillow casing is used to enclose these 
batts and to keep them in a useful configuration. These fiber-filled 
pillows are described as having a high degree of resiliency and 
fluffability, but are not contemplated as thermal insulation materials. 
BRIEF SUMMARY OF THE INVENTION 
The present invention provides a nonwoven thermal insulating batt having 
face portions and a central portion between the face portions comprising 
structural staple fibers and bonding staple fibers, the fibers being 
entangled and substantially parallel to the faces of the batt at the face 
portions of the batt and substantially parallel to each other and 
substantially perpendicular to the face portions of the batt in the 
central portion of the batt and the bonding staple fibers being bonded to 
structural staple fibers and bonding staple fibers at points of contact to 
enhance structural stability of the batt. 
The present invention also provides a method of making a thermal insulating 
nonwoven batt comprising the steps of 
(a) air-laying a web of structural staple fibers and bonding staple fibers, 
the web having face portions and a central portion between the face 
portions and the fibers being entangled and substantially parallel to the 
faces of the web at the face portions of the web and in an angled, layered 
configuration in at least the central portion of the web; 
(b) reconfiguring said web such that the fiber structure in the central 
portion of the web is substantially parallel and substantially 
perpendicular to the faces of the web; and 
(c) bonding the fibers of the reconfigured web to stabilize the web to form 
a nonwoven thermal insulating batt. 
The nonwoven thermal insulating batt of this invention has thermal 
insulating properties, particularly thermal weight efficiencies, about 
comparable to or exceeding those of down, but without the moisture 
sensitivity exhibited by down. The reconfiguration of the web increases 
the thickness and specific volume of the web and, thus, the reconfigured 
web has improved thermal insulating properties of the same web before 
reconfiguration. 
Mechanical properties of the batt such as its resilience, resistance to 
compressive forces, and density as well as its thermal insulating 
properties can be varied over a significant range by changing the fiber 
denier, bonding conditions, basis weight and type of fiber.

DETAILED DESCRIPTION OF THE INVENTION 
Structural staple fibers, usually single component in nature, which are 
useful in the present invention include, but are not limited to, 
polyethylene terephthalate, polyamide, wool, polyvinyl chloride and 
polyolefin, e.g., polypropylene. Both crimped and uncrimped structural 
fibers are useful in preparing the batts of the present invention, 
although crimped fibers, preferably having 1 to 10 crimps/cm, more 
preferably having 3 to 5 crimps/cm, are preferred. 
The length of the structural fibers suitable for use in the batts of the 
present invention is preferably from about 15 mm to about 75 mm, more 
preferably from about 25 mm to about 50 mm, although structural fibers as 
long as 150 mm can be used. 
The diameter of the structural fibers may be varied over a broad range. 
However, such variations alter the physical and thermal properties of the 
stabilized batt. Generally, finer denier fibers increase the thermal 
insulating properties and decrease the compressive strength of the batt, 
while larger denier fibers increase the compressive strength and decrease 
the thermal insulating properties of the batt. Useful fiber deniers for 
the structural fibers preferably range from about 0.2 to 15 denier, more 
preferably from about 0.5 to 5 denier, most preferably 0.5 to 3 denier, 
with blends or mixtures of fiber deniers often times being employed to 
obtain desired thermal or mechanical properties for the stabilized batt. 
Small quantities of microfibers, e.g., less than 20 weight percent, 
preferably melt blown microfibers in the range of 2-10 microns, may also 
be incorporated into the batts of the present invention. 
A variety of bonding fibers are suitable for use in stabilizing the batts 
of the present invention, including amorphous, meltable fibers, adhesive 
coated fibers which may be discontinuously coated, and bicomponent bonding 
fibers which have an adhesive component and a supporting component 
arranged in a coextensive side-by-side, concentric sheath-core, or 
elliptical sheath-core configuration along the length of the fiber with 
the adhesive component forming at least a portion of the outer surface of 
the fiber. The adhesive component of the bondable fibers may be bonded, 
for example, thermally, by solvent bonding, solvent vapor bonding, and 
salt bonding. The adhesive component of thermally bonding fibers must be 
thermally activatable (i.e., meltable) at a temperature below the melt 
temperature of the structural staple fibers of the batt. A range of 
bonding fiber sizes, e.g. from about 0.5 to 15 denier are useful in the 
present invention, but optimum thermal insulation properties are realized 
if the bonding fibers are less than about four denier and preferably less 
than about two denier in size. As with the structural fibers, smaller 
denier bonding fibers increase the thermal insulating properties and 
decrease the compressive strength of the batt, while larger denier bonding 
fibers increase the compressive strength and decrease the thermal 
insulating properties of the batt. The length of the bonding fiber is 
preferably about 15 mm to 75 mm, more preferably about 25 mm to 50 mm, 
although fibers as long as 150 mm are also useful. Preferably, the bonding 
fibers are crimped, having 1 to 10 crimps/cm, more preferably having about 
3 to 5 crimps/cm. Of course, adhesive powders and sprays can also be used 
to bond the structural fibers, although difficulties in obtaining even 
distribution throughout the web reduces their desirability. 
One particularly useful bonding fiber for stabilizing the batts of the 
present invention is a crimped sheath-core bonding fiber having a core of 
crystalline polyethylene terephthalate surrounded by a sheath of an 
adhesive polymer formed from isophthalate and terephthalate esters. The 
sheath is heat softenable at a temperature lower than the core material. 
Such fibers, available as Melty.TM. fibers from Unitika Corp. of Osaka, 
Japan, are particularly useful in preparing the batts of the present 
invention. Other sheath/core adhesive fibers may be used to improve the 
properties of the batts of the present invention. Representative examples 
include fibers having a higher modulus core to improve resilience of the 
batt or fibers having sheaths with better solvent tolerance to improve dry 
cleanability of the batts. 
The amounts of structural staple fiber and bonding staple fiber in the 
batts of the present invention can vary over a wide range. Generally, the 
batts preferably contain from about 20 to 90 weight percent structural 
fiber and about 10 to 80 weight percent bonding fiber, more preferably 
from 50 to 70 weight percent structural fiber and about 30 to 50 weight 
percent bonding fiber. 
The nonwoven thermal insulating batts of the invention are capable of 
providing thermal weight efficiencies of preferably at least about 20 
clo/g/m.sup.2 .times.1000, more preferably at least about 25 clo/g/m.sup.2 
.times.1000, most preferably at least about 30 clo/g/m.sup.2 .times.1000. 
The nonwoven batts of the present invention preferably have a bulk density 
of less than about 0.1 g/cm.sup.3, more preferably less than about 0.005 
g/cm.sup.3, most preferably less than about 0.003 g/cm.sup.3. Effective 
thermal insulating properties are achievable with bulk densities as low as 
0.001 g/cm.sup.3 or less. To attain these bulk densities, the batts 
preferably have a thickness in the range of about 0.5 to 15 cm, more 
preferably 1 to 10 cm, most preferably 2 to 8 cm, and preferably have a 
basis weight of from 10 to 400 g/m.sup.2, more preferably 30 to 250 
g/m.sup.2, most preferably 50 to 150 g/m.sup.2. 
The batts of the present invention are formed from air-laid webs of blends 
of structural staple fibers and bonding staple fibers. These webs, which 
can be produced on equipment, such as Rando Webber.TM. air-laying 
equipment, available from Rando Machine Corp., have a shingled structure 
which is inherent to the process. FIG. 1 illustrates a typical air-laid 
web 10 formed on Rando Webber.TM. air-laying equipment. The fibers are 
laid down in shingles 11 which normally are inclined at an angle of 
between about 10.degree. to 40.degree. to the faces of the web. Some of 
the most important factors influencing the angle of the shingle include 
the length of the fiber used to form the web, the type of collector used 
in the machine, and the basis weight of the web. 
Generally, longer fibers produce a web having a larger shingle angle than 
do shorter fibers. A web having a lower basis weight generally has a lower 
shingle angle than a similar web at a higher basis weight. The collector 
is generally an inclined wire or a perforated metal cylinder, the cylinder 
being preferred. Smaller diameter cylinders produce webs having a larger 
shingle angle than large diameter cylinders produce. The length of the web 
contact zone on the collector, i.e., the distance in which the web is in 
contact with the collector cylinder also affects the shingle angle with a 
longer distance creating a lower shingle angle. 
The shingled structure of the web can be used to advantage in creating a 
web structure that has superior thermal weight efficiency to down and that 
also has the resiliency of down. By reconfiguring the shingle structure 
from its original shallow angle of 10.degree. to 40.degree., as shown in 
FIG. 1, to an angle of at least above 50.degree., preferably at least 
about 60.degree.; and most preferably approaching 90.degree., i.e., 
80.degree.-90.degree., as illustrated in FIG. 2, the web becomes a 
substantially columnar structure which is capable of enduring compressive 
challenges and providing lower bulk densities than those associated with 
the starting web. The reconfigured web structure capitalizes on the 
natural resilience of the fibers by orienting them substantially 
lengthwise to the compressive forces exerted on the web. 
Several methods are presently available to effect the reconfiguration of 
the shingled structure in an air laid web, including, but not limited to, 
running two conveyer belts at differing speeds so as to move one face of 
the web at a faster down-web speed than the other, a "lift" process, a 
"sag" process and an optional "combing" or "brushing" step which can be 
added to either the "lift" or "sag" processes to cause an additional 
reconfiguring, or repositioning, of the fibers in the web. 
In the "lift" process, illustrated in FIG. 3, air-laid web 31, which has 
the above-described shingle structure, passes from a first transport means 
32, such as a conveyer belt, to a second transport means 33, such as a 
second conveyor belt, which is positioned slightly higher than first 
transport means 32. By "lifting" the web in this manner, the bottom 
surface of web 34 is shifted forward relative to the top surface of the 
web and the shingle structure 35 is concurrently moved toward a more 
vertical fiber configuration wherein the shingles of the web become more 
perpendicular to the surface. This process may require several "lifts" to 
achieve the desired amount of reconfiguration. In FIG. 3, a "brush" 36, 
which consists of a rectangular piece of 40-pound card stock 37 which is 
hinged at its top edge 38 so that the bottom edge 39 lightly brushes the 
top of the web is utilized to introduce further reconfiguration of the 
shingle structure. 
In the "sag" process illustrated in FIG. 4, air-laid web 41, which has the 
above-described shingle structure, is allowed to drop from a first 
transport means 42, such as a conveyor belt, in an unsupported fashion, 
and then to develop a "sag" 43 before being picked up by a second 
transport means 44, such as a second conveyor belt. The "sag" causes the 
fibrous shingles of the web to move relative to one another and to the 
faces of the web such that a more vertical fiber structure is produced in 
the web whereby the shingles become more perpendicular to the surface. The 
addition of a comb 45, such as a 15 dent comb, which lightly contacts the 
top surface of the web after the "sag" can be used to introduce further 
reconfiguration of the fibers, i.e., to cause the fibers to be even more 
closely vertical to the web face. This "sag" process is generally more 
efficient than the "lift" process, but may be less controllable, and, 
therefore, the "lift" process is generally preferred. 
While each of these processes results in a reconfiguration of the shingle 
structure in the central portion of the web, the comparatively 
non-directional, highly entangled fiber structure on the top and bottom 
faces of the batt which results from the air laying of the web is not 
significantly altered. 
After the web has been reconfigured, the web is heated sufficiently to 
effect interfiber bonding by the bonding fibers with other bonding fibers 
and with structural fibers to stabilize the reconfigured web to form the 
nonwoven thermal insulating batt of the invention. The temperature of the 
oven in which the web is heated is preferably about 40.degree. to 
70.degree. C. above the temperature at which the adhesive portion of the 
bondable fiber melts. 
The nonwoven thermal insulating batts of the present invention exhibit 
outstanding thermal insulating properties about comparable to or exceeding 
those of natural and synthetic down products. While the reasons for this 
outstanding performance are not fully understood at this time, it is 
speculated that the columnar structure of the reconfigured web contributes 
not only to the resilience of the web but also to reducing heat losses 
from radiation. It is suspected that this possible contribution of the 
columnar structure to reducing heat loss by radiation may be due to the 
fact that fibers radiate heat outward from their surface and with 
perpendicular fibers radiation is predominantly within the plane of the 
batt rather than outward from the batt. 
While the principal application for the batts of the present invention lies 
in the area of light weight thermal insulation materials, they are also 
useful for a number of other areas, including acoustical insulation and 
cushioning applications where the work to compress, resilience, and loft 
retaining properties of the batts can be advantageously utilized. 
The following examples further illustrate this invention, but the 
particular materials and amounts thereof in these examples, as well as 
other conditions and details, should not be construed to unduly limit this 
invention. In the examples, all parts and percentages are by weight unless 
otherwise specified. 
In the examples, thermal resistance of the batts was evaluated with the 
heat flow upward, according to ASTM-D-1518-64, to determine the combined 
heat loss due to convection, conduction and radiation mechanisms. Heat 
losses due to the radiation mechanism were determined using a Rapid-K unit 
(Dynatech R/D Company of Cambridge, MA) with the heat flow downwards. 
EXAMPLES 1-6 
Structural fibers (SF) and bonding fibers (BF) were opened and mixed using 
type B, Rando Webber.TM. air-laying equipment with the amounts and types 
of fibers as follows: 
Example 1: 60% SF (Fortrel.TM. Type 510, a polyethylene terephthalate 
fiber, 1.2 denier, 3.8 cm long, available from Celanese Corp.) and 40% BF 
(Melty.TM. Type 4080, a bonding core/sheath fiber, 2 denier, 5.1 cm long, 
available from Unitika Corp.); 
Example 2: 60% SF (Fortrel.TM. Type 417, a polyethylene terephthalate 
fiber, 1.5 denier, 3.8 cm long, available from Celanese Corp.) and 40% BF 
(Melty.TM. Type 4080, a bonding core/sheath fiber, 4 denier, 5.1 cm long, 
available from Unitika Corp.); 
Example 3: 60% SF (Fortrel.TM. Type 510) and 40% BF (Melty.TM. Type 4080, 4 
denier, 5.1 cm long); 
Example 4: 45% SF (Fortrel.TM. Type 510), 10% SF (Kodel.TM. Type 431, a 
polyethylene terephthalate fiber, 6 denier, 3.8 cm long, available from 
Eastman Chemical Products, Inc.), and 45% BF (Melty.TM. Type 4080, 2 
denier, 5.1 cm long); and 
Example 5: 65% SF (Fortrel.TM. Type 510) and 35% BF (Melty.TM. Type 4080, 4 
denier, 5.1 cm long); and 
Example 6: 60% SF (Fortrel.TM. Type 510) and 40% BF (Melty.TM. Type 4080, 2 
denier, 5.1 cm long). 
The opened and mixed fiber blends were then air-laid using type B Rando 
Webber.TM. air-laying equipment to produce air-laid webs. In Examples 1-4, 
the web was reconfigured by allowing the web to sag to a depth of about 7 
cm in an unsupported manner between a first conveyer, a slot conveyer, and 
a second conveyer, a galvanized wire screen conveyer, having a 10 cm 
linear gap between conveyers, the second conveyer being about 30 cm above 
the first conveyer, and the first conveyer travelling at a rate of 2.4 
m/min and the second conveyer traveling at a rate of 2.7 m/min. In 
Examples 5 and 6, the web was reconfigured by lifting the web from a first 
conveyer to a second conveyer, the second conveyer being 0 cm linearly 
distant and 30 cm above the first conveyer, and both conveyers traveling 
at a rate of 2.7 m/min. In Examples 1, 5, and 6, the web was further 
reconfigured by brushing the top of the web with a hinged panel of 
40-pound/ream stiff card stock paper. In Example 2, the web was further 
reconfigured by combing the top of the web with a 15-dent textile loom 
comb. Each reconfigured web was then passed through an air circulating 
oven at the temperature and dwell time set forth in Table I to achieve a 
stabilized batt having the basis weight set forth in Table I. The 
thickness of each batt was determined with a 13.8 Pa force on the face of 
the batt and the reconfigured shingle angle was measured. The thermal 
insulating value for each batt was measured and the weight efficiency and 
thermal insulating value per cm thickness were determined. The results are 
set forth in Table I. 
TABLE I 
______________________________________ 
Example 1 2 3 4 5 6 
______________________________________ 
Oven temp. 
160 155 155 155 160 160 
(.degree.C.) 
Dwell time 
120 120 150 120 135 120 
(sec) 
Basis wt. 
67 70 90 149 142 68 
(g/m.sup.2) 
Thickness 
2.5 2.0 2.6 4.5 3.8 2.8 
(cm) 
Bulk density 
0.0027 0.0035 0.0035 
0.0033 
0.0037 
0.0024 
(g/cm.sup.3) 
Reconfigured 
60-70 60-70 60-70 80-90 70-80 60-70 
shingle 
angle (.degree.) 
Thermal 2.12 1.91 2.42 3.56 2.78 2.08 
resistance 
(clo) 
Weight 31.6 27.3 26.9 23.9 19.6 30.6 
efficiency 
(clo/g/m.sup.2 .times. 
1000) 
Clo/cm thick- 
0.85 0.95 0.92 0.79 0.73 0.75 
ness 
______________________________________ 
As can be seen from the data in Table I, the thermal insulating batts of 
the invention have excellent thermal resistance. The batts of Examples 1 
and 6 possess exceptionally superior thermal weight efficiencies at low 
bulk densities. 
EXAMPLE 7 AND COMATIVE EXAMPLES C1-C3 
Samples of Quallofil.TM., available from DuPont, Inc. (Comparative Example 
C1), Hollofil.TM. 808, available from DuPont, Inc. (Comparative Example 
C2), an unbranded commercially available, resin bonded thermal insulation 
material, (Example C3), and a sample of batt prepared as in Example 1, 
except having a basis weight of 75 g/m.sup.2, (Example 7) were tested for 
basis weight, thickness, clo value, and weight efficiency. Then a sample 
of each batt, 28 cm.times.56 cm was placed between two sheets of woven 
nylon fabric, 28 cm.times.56 cm, and the perimeter edges were sewn 
together to form a panel to simulate garment construction. Each panel was 
used as a seat cushion, being subjected to repeated compressions, 
twisting, and sideways forces, for eight days. Each panel was then fluffed 
for 45 minutes in a clothes dryer on air fluff cycle, the batt measured 
for thickness, clo value, and weight efficiency, then laundered in a 
Maytag.TM. home washer using 41 minutes continuous agitation with warm 
water, and a gentle cycle followed by normal rinse and spin, and dried in 
a Whirlpool.TM. home dryer at medium heat on permanent press cycle after 
each laundering. The thickness, clo value, and weight efficiency of each 
batt were again measured. All test results are set forth in Table II. 
TABLE II 
______________________________________ 
Example 7 C1 C2 C3 
______________________________________ 
Basis weight (g/m.sup.2) 
75 145 116 157 
Bulk density (g/cm.sup.3) 
Initial 0.0024 0.0044 0.0054 
0.0052 
Fluffed 0.0051 0.0055 0.0056 
0.0067 
Laundered 0.0045 0.0055 0.0059 
0.0069 
Thickness (cm) 
Initial 3.2 3.3 2.2 3.0 
Fluffed 1.5 2.7 2.1 2.4 
Laundered 1.7 2.7 2.0 2.3 
Thermal resistance (clo) 
Initial 2.6 3.3 2.8 2.8 
Fluffed 1.9 2.8 2.2 2.5 
Laundered 2.0 2.4 1.9 2.3 
Weight efficiency 
(clo/g/m.sup.2 .times. 1000) 
Initial 34.9 22.4 23.7 17.5 
Fluffed 25.5 19.3 19.2 15.7 
Laundered 26.4 16.7 16.2 14.3 
______________________________________ 
As can be seen from the data in Table II, the batt of Example 7 had greater 
thermal weight efficiency initially and after compression, fluffing, and 
laundering than the comparative thermal insulating materials. 
EXAMPLE 8 AND COMATIVE EXAMPLES 4-9 
For Example 8, a batt was prepared as in Example 1, except that the basis 
weight was 70 g/m.sup.2. The thermal conductivity for this batt was 
determined using a Rapid-K unit with the heat flow downward and series of 
reduced spacings between the hot and cold plates to increase bulk density. 
Linear regression analysis of the data using bulk density (kg/m.sup.3) and 
the product of the bulk density and thermal conductivity (W/mK) provided 
an equation where the radiation parameter is given by the intercept of the 
equation at zero bulk density. Similar determinations were also determined 
for two commercially available materials: Quallofil.TM., 145 g/m.sup.2, 
available from DuPont, Inc., and a 157 g/m.sup.2 commercially available 
resin bonded thermal insulating material. The results are set forth in 
Table III together with radiation parameters calculated from published 
data for the other listed thermal insulating materials. 
The radiation parameter is particularly useful in determining the relative 
thermal emissivity of thermal insulating materials. Radiation heat losses 
become a more important factor in very low density materials where the 
fiber mass is small and heat loss due to thermal conductivity is 
minimized. The lower the radiation parameter, the lower the heat loss due 
to thermal radiation. 
TABLE III 
______________________________________ 
Thermal insulating 
Radiation 
Example material parameter 
______________________________________ 
8 Batt of invention 
114 
C4 Quallofil .TM. 184 
C5 Unbranded material 
290 
C6 Synthetic down 137 
(U.S. Pat. No. 4,588,635) 
C7 Polarguard .TM. 233 
C8 Hollofil .TM. II 
295 
C9 Down 137 
______________________________________ 
As can be seen from the data in Table III, the thermal insulating batt of 
Example 8 yielded a lower radiation parameter than any of the comparative 
thermal insulating materials including down. 
EXAMPLE 9 AND COMATIVE EXAMPLES C10-C11 
Thermal insulating weight efficiency determinations were made on a batt 
prepared as in Example 2 (Example 9), Quallofil.TM. thermal insulating 
material having a basis weight of 145 g/m.sup.2 and a thickness of 3.3 cm 
(Comparative Example C10), and unbranded commercially available thermal 
insulating material having a basis weight of 157 g/m.sup.2 and a thickness 
of 3.1 cm (Comparative Example 11). Samples of each material were 
subjected to forces of compression and tested for thermal efficiency under 
compression. The results of these tests are shown in FIG. 5, where the 
solid line (A) represents the weight efficiency of the batt of Example 9 
and the dotted line (B) and broken line (C) represent the weight 
efficiencies of the thermal insulating materials of Comparative Examples 
C10 and C11, respectively. 
As can be seen from FIG. 5, the thermal insulating batt of Example 9 had 
better thermal weight efficiency at various thickness fractions than 
either the Quallofil.TM. or unbranded thermal insulating materials.