Plastic and nonmetallic article shaping or treating: processes – Direct application of fluid pressure differential to... – Producing multilayer work or article
Reexamination Certificate
2001-08-28
2004-01-13
Staicovici, Stefan (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Direct application of fluid pressure differential to...
Producing multilayer work or article
C264S511000, C264S248000, C264S255000, C264S257000, C264S258000, C264S137000, C156S286000, C156S289000, C156S309600, C156S382000
Reexamination Certificate
active
06676882
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to infusion of resin into a woven textile and particularly relates to hot-melt infusion into three-dimensional, woven, textile preforms.
2. Description of the Prior Art
Generally, laminating resins are used as the matrix material in woven textiles., this also being true for woven preforms used to connect components made of composites or other materials. An example of a commonly-used laminating resin is 977-3, available from Cytec Industries, Inc., of West Paterson, N.J. Typically, the laminating resin is filly infused into a textile product, wetting all of the fiber bundles in the preform and forming a “prepreg,” or pre-impregnated textile. The resin is later cured to form a polymer matrix in the finished composite component. Methods of fully impregnating flat textiles include immersing in a solution, pressing with rollers, and pulling through a die. All of these methods have the advantage of being able to do continuous lengths.
In solution impregnation, the resin is dissolved in a solvent, and the textile is immersed in the solution. The textile is then removed from the solution, and the solvent is evaporated, leaving the resin in the textile. The disadvantages of this method are that resin content is difficult to control and that the volatile gases must be removed.
FIG. 1
shows a prior art method of infusing resin into a textile
11
by placing resin film
13
against textile
11
and feeding them between a pair of heated rollers
15
. Rollers
15
heat and press resin
13
into textile
11
, transferring the resin
13
into textile
11
.
FIG. 2
shows a second prior art method of infusing resin. The pultrusion method of infusing a textile
17
with resin
19
involves pulling textile
17
through a heated die
21
. Resin
19
is placed against textile
17
, and these are fed into the die to heat resin
19
and infuse textile
17
. Die
21
may also cure resin while textile
17
is within die
21
.
While these techniques work well for flat textiles, infusion of three-dimensional textile preforms presents different problems. The prior-art methods described above may be used to fully infuse 3-D preforms, but the preforms may have too much resin at intersections, causing the preform to be overly bulky in those areas. Also, a fully-infused preform tends to be stiff and less pliable, making the preform difficult to handle or position during assembly.
SUMMARY OF THE INVENTION
A method provides for full or partial infusion of resin into three-dimensional, woven, textile preforms. Resin film is placed at selected locations adjacent the preform, and the resin film may be separated from other areas of the preform using separator sheets or other materials. The preform is heated and may be vacuum-bagged to apply pressure, or may be rolled or fed through a die. The heat and pressure cause the resin to infuse into the selected areas of the preform adjacent the resin films. The amount of resin in the partial infusion is the same as is necessary to fully infuse the preform, but the resin remains localized in the selected areas until heated again at cure to cause the resin to flow throughout the preform. The method may also be used to fully infuse the preform with resin by providing sufficient temperature and time at that temperature during the initial infusion.
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U.S. patent application Ser. No. 09/648,321, filed Aug. 25, 2000.
U.S. patent application Ser. No. 09/898,633, filed Jul. 2, 2001.
Benson Ross A.
Bersuch Larry R.
Miller Harry R.
Repecka Linas
Schmidt Ronald P.
Lockheed Martin Corporation
Staicovici Stefan
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