A method of installing fragile, light-weight, high-temperature fiber insulation, particularly where the insulation is to be used as a seal strip providing a high order of thermal barrier insulation is described. The process is based on provision of a strip of the mineral batting cut oversize by a predetermined amount, saturated in a fugitive polymer solution, compressed in a mold, dried and cured to form a rigidized batting material which may be machined to required shape. The machined dimensions would normally be at least nominally less than the dimensions of the cavity to be sealed. After insertion in the cavity, which may be a wire-mesh seal enclosure, the apparatus is subjected to baking at a temperature sufficiently high to cause the resin to burn off cleanly, leaving the batting substantially in its original condition and expanded into the cavity or seal enclosure

Ballantine, T. J.

English

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NASA CASE N0. 14'1}^	 ^J ^i l
PRINT FIG.
NOTICE
The invention disclosed in this document resulted from
research in aeronautical and space activities performed under
programs of the National Aeronautics and Space Administration.
The invention is owned by NASA and is, therefore, available for
licensing in accordance with the NASA Patent Licensing
Regulation (14 Code of Federal Regulations 1245.2).
To encourage commercial utilization of NASA-owned inventions,
it is NASA policy to grant licenses to commercial. concerns.
	
1
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Address inquiries and all applications for license for this
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(NASA-Case-MSC-189;34-3) A ME'THGD AND N82-26387	 JSC
TECHNIQUE FO" INSTALLING LIGHT-WEIGHT
FRAGILE, HIGH-TEMPERATURE FIBER INSULATION	 Unclas
Patent Application (NASA) 10 P CSCL 11D G3/24^ 199^4^7
NG A02/Hl A01
u^ 	 y
NASA CASE NO, IVISC-16934'1
APPLICATION FOR LETTERS PATENT
5
J
TO ALL WHOM IT MAY CONCERN:
BE 'IT KNOWN THAT 1,
10	 Bhanu C. Patel, a citizen of the United States of America and resident of
Downey, California, have invented certain new and useful Improvements In
a method and tdchnlque for installing light-weight, fragile, high-temperature
fiber Insulation of which the following is a specifications
15
ABSTRACT OF THE DISCLOSURE
A method of installing fragile, light-weight, high-temperature
fiber insulation., particularly where the insulation is to be used as a seal strip
providing a high order of thermal barrier Insulation. The process is based on
provision of a strip of the mineral batting cut oversize by a predetermined amount,
20	 saturated in a fugitive polymer solution, compressed in a mold, dried and cured
to form a rigidized batting material which may be machined to required shape.
The machined dimensions would normally be at least nominally less than the
dimensions of the cavity to be sealed. After insertion in the cavity, which may be
a wire-mesh seal enclosure, the apparatus is subjected to baking at a temperature
25	 sufficiently high to cause the resin to burn off cleanly, leaving the batting sub-
stantially in its original condition and expanded into the cavity or seal enclosure,
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AWARDS ABSTRACT	 NASA Case No. MSC-16934
A METHOD AND 'TECHNIQUE FOR INSTALLING LIGHT-WEIGHT
FRAGILE, HIGH-TEMPERATURE FIBER INSULATION
The invention relates to a- method of installing fragile, light-
weight, high-temperature firer insulation, particularly where the
insulation is to be used as a seal strip providing a high order of
thermal barrier insulation.
According to the invention, light-weight insulation batting such as
alumina/zrconia or preferably, saffil high-temperature insulation
alumina fiber 4 is precut into oversize elongated shapes. These shapes
are saturated in an acrylic polymer resin in water solution, and com-
pressed in a mold (Fig 2) to the required thickness or cross-sectional
dimensions. The saturated batting is then dried in the mold and the
resin cured at an appropriate temperature. The resulting rigidized
batting may then be machined to a particular required shape and required
dimensions for installation in wire-mesh sleeving 7, or any cavity requiring
the heat-barrier seal to be provided. The entire assembly is subsequently
heated to a temperature much greater than the res in curing temperature to
effect a clean burn-off of the resin material, leaving the original
mineral batting material to expand into the interior shape of the
containing cavity or wire-mesh sleeving if the insulation material is
to be used as a heat seal around an openable,door or hatch, for example.
In connection with certain recoverable space vehicles, high performance
heat-sealing must be provided in places such as entry hatches, landing
gear doors, etc., since the vehicle skin temperatures become extremely
high during certain times in the atmospheric reentry and the return
maneuvers. The method, which is the subject of the present invention,
is particularly well adapted for that purpose as will be more fully
understood as this description proceeds. The method and materials used
therein, wherever a fragile fiber batting is impregnated with an
organic resin binder, compressed and machined to a required shape for
insertion into a cavity for insulation purposes, then heated whereby
the resin binder burns off to permit the batting to expand and fill
the cavity is considered novel.
Inventor:
	
Bhanu C. Patel
Employer:	 Rockwell International, NAS9-14000
Space Systems Group
12214 Lakewood Boulevard
Downey, CA 90241
Initial Evaluator:
N
Thomas J. Ballantine
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OF POOR QUALITY
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NASA CASE NO. 11VISC-16034.3
ORIGINAL PAGE IS
OF POOR QUALITY
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APPLICATION FOR LETTERS PATENT
5 {
TO ALL WHOM IT MAY CONCERN:
BE IT KNOWN THAT I,
i
10
	
Bhanu C. Patel, a citizen of the United States of America and resident of
Downey, California, have Invented certain new and useful Improvements In
a method and technique for installing light-welght, fragile, high-temperature
fiber insulation of which the following Is a specification;.
15
ABSTRACT  OF THE DISCLOSURE,
A method of Installing fragile, light-weight, high-temperature
fiber insulation, particularly where the insulation Is to be used as a seal strip
providing a high order of thermal barrier insulation. The process Is based on
provision of a strip of the mineral batting cut oversize by a predetermined amount,
20	 saturated in a fugitive polymer solution, compressed in a mold, dried and cured
to form a rigidized batting material which may be machined to required shape.
The machtncddimensions would normally be at least nominally less than the
dimensions of the cavity to be sealed. After Insertion In the cavity, which may be
a wire-mesh seal enclosure, the apparatus is subjected to baking at a temperature
25	 sufficiently high to cause the resin to burn off cleanly, leaving the batting sub-
stantally in its original condition and expanded into the cavity or seal enclosure,
A
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OF POOR QUALITY f	 ,
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BACKGROUND OF THE INVENTION
} a .	 Field of the Invention
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The field of art to which the invention pertains generally, is the
5 field of insulation Installation, and more particularly, to installation of fragile
fibrous, high-temperature Insulation used as a high-temperature seal.
r'
2.	 Descrt2tton of the Prior Art
10 The concept of employing fugitive binders is known, per se, and
has been employed in the ceramics Industry,
	
In the ceramics Industry, intense ►
heating or baking (firing) can be rotted upon to evolve or drive off fugitive binder
materials used lo g- temporary convenience during manufacturing.	 In general,
the fugitive binder material , per se, is not used to preform a compressible
15 fibrous material i!i reduced volume, However,
In U.S. Patent 2, 607,714 temporarily fabricated inorganic fiber
i
shapes are described, 	 The fiber materials are recognized as fragile and subject
to damage in normal handling, transportation and application. 	 For the purpose,
i
a temporary adhesive material is applied to preserve the shape of the material,
20 such as fiberglass, etc,, and when in place in their intended use, the adhesive is rJ
t
flushed froth the material, using a non-contaminating solvent, for example, water,
''
k-i A suggested fugitive adhesive or binder in that reference is hydroxy-ethyl cellulose,
1
which is readily soluble in cold racer.'
In U.S. Patent 3, 546, 846, there is described a method and apparatus
:F
k	 25 for packaging individual lengths of compressible integrated glass finer teats. 	 A
length of such a fiberglass mat is compressed without breaking individual glass fibers3
In the mat by evacuating air from within lt.	 An air impervious backing and top cover
r T^
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Oi 1 0NAL PAGE 19
OF POOR QUALITY
are than sualed together to retain the mat in its evacuated and compressed state.
That reference may be thou olit of as describing an alternative ""packaging ,, method
for the fibrous insulation material, however, stops for the restoration of insulation
material volume in order to have it fill voids or cavities into which it is emplaced,
is not evident. Presumably, however, puncture of the packaging would permit
expansion of the mats,
None of the aforementioned methods and apparatus provide a
satisfactory method for Inserting light-weight batting of fragile, high-temperature
mineral fibers into assembly such as special fabric covered nozzle seals or wire
sleeving.
In accordance with the foregoing, the manner in which the present
invention provides a unique process for forming heat-barrier seals which are
readily handled and installed without di:ii;rt p j; rating the fibrous structure thereof,
will be understood as this description proceeds.
SUMAIARY OF THE INVENTION
According to the invention, light-weight insulation batting such as
alumina/zirconta, or preferably, saffil high -tecr,N4rature alumina fiber is precut
into oversize elongated shapes, These shapes are saturated in.an acrylic polymer
resin in water solution, and compressed in a mold to the required thickness or
cross-sectional dimensions. The saturated batting is then dried in the mold and
the resin cured at an appropriate temperature. The resulting r gidized batting may
then be machined to a particular required shape and required dimensions for
installation in wire-mesh sl eeving , or any cavity requiring the heat-barrier seal
to be provided. The entire assembly is subsequently heated to a temperaWr.- much
greater than the resin curing temperature to effect a clean burn-off of the resin
5
10
15
20
25
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1- pou? QUALITY
material, leaving the original mineral batting material to oxpand Into the interior
shape of the containing cavity or wire-mesh sleeving if the Insulation material is
r
to.be used as a heat seal around an openable door or hatch, for example, 	 01.
In connection with certain recoverable space vehicles, high per-
5	 formanee heat-sealing must be provided In places such as entry hatches, landing
gear doors, etc, , since the vehicle skin temperatures became extremely high during
certain tittles In the atmospheric re-entry and the return maneuvers. The-method,
which is the subject of the present invention, is particularly well adapted for that
purpose as will be more fully understood a,.s this description proceeds. 	 W
BRIEF DESCRIPTION GIB THE DRAWINGS
FIG, 1 Is an exploded view of tho compression tooling used In the
r
rigidizing step according to the Invention.
FIG, 2 Is an end-view of tooling used In the r[gLdizing process
according to the invention, for the production of rigidized batting of circular
cross-section.
20
	
	
FIG. 3 shows the step of Inserting a rigidized resin-filled fiber
member into a wire sleeve.
DESCRIPTION OF ' 141 PREFERRED :I IMBODDITENTS
25
	
	
The method of the invention will be described with particular
reference to the aerospace application aforementioned, and the materials referred
to will be those appropriate to that application. It is to be. understood however,
-4-
10
16
ORIGINAL WAGE {R
OF POOR QUALITY
that other less exotic materials might be substituted in lass demanding industrial
applications.
Before referring to the drawings in detail, it must be first realized
that a roughly cut elongated shape of the saffil high-t'emperature alumina fibrous
5 1iraterial is first provided. The size of such a strip exceeds the cavity into which
it Is to be placed, since In the final analysis It will have been permitted to expand
and fill the said cavity completely.
The pre-out or roughly cut alumina batting strip is next saturated
In the acrylic polymer resin solution, for example, a material Identified as A-3
10	 as manufactured by Rohm and Haas Company. That material is prepared In a
water solution, preferably with distilled water, diluted to about five percent solid
content. Saturation of the fiber batting in that solution is a simple matter requiring
only its Immersion In the solution. The saturated fiber strips are then placed In
the compression tool which may be relatively simple, and will vary in shape accord-
15	 ing to the application, Figs. 1 and 2 illustrate tooling suitable for +;his compression
stop and will be described hereinafter. The compression provided by the tooling not
only compresses tho fibrous batting to a dimension in accordance with which it is
easily placed in the cavity or wire sleeve for which it is intended, and also serves
to squeeze out excess resin solution. The compressed bats are allowed to remain
20	 in the compression fixture, typically for a time of sixteen hours or more at ambient
temperatures. Without removing the compressed bats from the fLxturo, the resin
Is next cured In a pre-heated air-circulating oven preferably at 250 0 F * 100.
The curing-drying time at that temperature is continued for a time dependent upon
the size of the batting strip being processed, but ordinarily for a period oil the order
25	 of four to eight hours.
i
I	 Disassembly of the fixture and removal of the cured compressed
0
batting strip is undertaken when cooling to 150 (1) or below has occurred.
Referring now to Fig. 1, an axially or longitudinally sectioned view
l	 -5-
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kORIGINAL PACK. IS
OF POOR QUALITY
of typical tooling (fixture) for producing a fiber strip of essentially rectangular
cruse - sectional shape is shown, A solution impregnated fiber material
(sliotivn in the compressed shape; for convenience) is essentially inserted between
two caul plates , I and la with separate,,, films, 2 and 2a between, as shown,
ri	 These separator films might be of a fluorocarbon or fiberglass material to
avoid adherence of the compressed fibrous material strip r:o the caul plates
1 and la, the latter being metal plates ordinarily, Spacer blocks 3 and 3a -are
used to predetermine the length of each conipressod fibrous material strip
produced, although the impregnated compressed and cured material can be out
10	 to length if it is processed without spacers 3 and 3a according to Fig. 1.
Referring now to Fig. 2, an equivalent tooling for producing the
compressed fibrous strip 4a in circular cross-saetion is shown. The caul plates
5 and 5a are appropriately shaped and the separator films 0 and Ga are similarly
shaped or May be of a sprayed on fluorocarbon material equivalent in composition
15	 and) function to films 2 and 2a of Fig. 1.
Ileferring now to Fig. 3, a compressed and cured fibrous insulation
member as might have been produced by the fixture of Fig. 2 is shown being inserted
into a tubular-shaped wire mesh. SuMclont clearance is extant to permit easy
insertion of the stiffened fibrous strip 4a into the wire sleeve 7.
20	 Once this element 4a has boon fully inserted into .wire sleeve 7, that
0
assembly is baked or fired at a temperature on the order of 800 F. The organic
resin binder being thoroughly and cleanly driven off. in the absence of the fugitive
binder material, the batting expands to uniformly and completely fill the wine mesh
sleeving, the resulting product , being easily handled and effectively contained for
25	 emplacement as a door heat-sealing material, or the like.
In the event that the shaped rigidlzed batting is to be placed in a
structural cavity directly, it can be cut, milled or otherwise machined in this
1,4.
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ORIGINAL RAG;" Is
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rigldized form to effect oonformance to the said cavity,
S
a	 The method of the Invention permits rapid and improved placonlent
A
E	 of light-weight thermn-htirrler insulation batting with substantially no hazard of
o
4	 damage to the fiber and with minimal labor expenditure, The $00 ^ firing :step for4
5	 driving off the fugitive binder is, of course, applied in all eases as a final step,
►
The process will be recognized as basically' applicable to the
production of improved Beat-barriers and seals, such as might be required in
Industrial ovens, autoclaves, kilns, and the like,
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A method and technique for installing light-weight fragile, high-temperature fiber insulation

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