18
1
wet finishing and a high degree of drape. The drapeability of
a satin weave is considered to be the best. Therefore, satin
weaves will adapt to any curvilinear profile during moulding. The flat nature of satin fabric gives low crimps; therefore, its mechanical properties are good. The asymmetry
and low stability during handling are the two important
aspects of a satin weave. The warp yarn and satin weave
interlace over 3, 4, 5, or 8 weft yarns and under 1 weft yarn.
The harness of a satin weave is decided by interlacing a warp
yarn with the maximum number of weft yarn. It is difficult
to handle satin-weave fabric having a harness of 5 or above.
Also, care needs to be taken to hide the assembled multiple
layers of these fabrics for making composites so that
residual stresses are not built into the composite due to the
asymmetric effect of weave. The 4-harness satin weave
pattern is shown in . Fig. 1.5d.
5 Leno—A leno weave is primarily developed for locking the
open ends of the fabric during weaving. It is also referred to
as leno selvedge. It improves the stability in ‘open’ fabrics
that have a low fibre count. Leno is a form of plain weave
where twisted warp yarn effectively locks each weft yarn. In
this weave, warp yarns are twisted around consecutive weft
yarns, forming a spiral pair. Leno weaves are normally used
in conjunction with other weave patterns in fabrics in order
to avoid their openness so that effective composites are
formed. The role of a leno weave becomes very prominent
for the handling of satin weaves with a harness 5 and above.
The leno weave pattern is shown in . Fig. 1.5e.
5 Mock Leno Weave—This is also a version of plain weave in
which occasional warp yarns deviate from the alternate
under overinterlacing of plain weave and rather interlace
every two or more weft yarns. The same pattern is repeated
in the weft direction, and the resultant fabric has an
increased thickness, rougher surface, and additional
porosity. The mock leno weave pattern is shown schematically in . Fig. 1.5f.
5 Chopped Strand Mat (CSM)—CSM is a nonwoven sheet of
glass fibre. In CSM, long staple fibres (up to 50 mm) are
placed in random orientation in the form of a sheet. The
glass strands are adhesively bonded. The glass CSM is
available in areal density of 300, 450, 600, and 900 GSM
(gram per square metre). The CSM pattern is shown in
. Fig. 1.5g. CMS has extremely good adaptability to any
shape; therefore, it is used in many applications, such as
boat hulls, water tanks, composite furniture, etc. The matrix
often used with glass CSM is polyester resin. The products
made out of CSM are almost transparent to light.
The comparison of properties with weave styles is given in
. Table 1.8.
5 Woven Fabrics vs. Woven Rovings—Yarn-based fabrics generally give higher strengths per unit weight than roving. These
Chapter 1 · Introduction
1
wet finishing and a high degree of drape. The drapeability of
a satin weave is considered to be the best. Therefore, satin
weaves will adapt to any curvilinear profile during moulding. The flat nature of satin fabric gives low crimps; therefore, its mechanical properties are good. The asymmetry
and low stability during handling are the two important
aspects of a satin weave. The warp yarn and satin weave
interlace over 3, 4, 5, or 8 weft yarns and under 1 weft yarn.
The harness of a satin weave is decided by interlacing a warp
yarn with the maximum number of weft yarn. It is difficult
to handle satin-weave fabric having a harness of 5 or above.
Also, care needs to be taken to hide the assembled multiple
layers of these fabrics for making composites so that
residual stresses are not built into the composite due to the
asymmetric effect of weave. The 4-harness satin weave
pattern is shown in . Fig. 1.5d.
5 Leno—A leno weave is primarily developed for locking the
open ends of the fabric during weaving. It is also referred to
as leno selvedge. It improves the stability in ‘open’ fabrics
that have a low fibre count. Leno is a form of plain weave
where twisted warp yarn effectively locks each weft yarn. In
this weave, warp yarns are twisted around consecutive weft
yarns, forming a spiral pair. Leno weaves are normally used
in conjunction with other weave patterns in fabrics in order
to avoid their openness so that effective composites are
formed. The role of a leno weave becomes very prominent
for the handling of satin weaves with a harness 5 and above.
The leno weave pattern is shown in . Fig. 1.5e.
5 Mock Leno Weave—This is also a version of plain weave in
which occasional warp yarns deviate from the alternate
under overinterlacing of plain weave and rather interlace
every two or more weft yarns. The same pattern is repeated
in the weft direction, and the resultant fabric has an
increased thickness, rougher surface, and additional
porosity. The mock leno weave pattern is shown schematically in . Fig. 1.5f.
5 Chopped Strand Mat (CSM)—CSM is a nonwoven sheet of
glass fibre. In CSM, long staple fibres (up to 50 mm) are
placed in random orientation in the form of a sheet. The
glass strands are adhesively bonded. The glass CSM is
available in areal density of 300, 450, 600, and 900 GSM
(gram per square metre). The CSM pattern is shown in
. Fig. 1.5g. CMS has extremely good adaptability to any
shape; therefore, it is used in many applications, such as
boat hulls, water tanks, composite furniture, etc. The matrix
often used with glass CSM is polyester resin. The products
made out of CSM are almost transparent to light.
The comparison of properties with weave styles is given in
. Table 1.8.
5 Woven Fabrics vs. Woven Rovings—Yarn-based fabrics generally give higher strengths per unit weight than roving. These
Chapter 1 · Introduction