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United S t a t e s
Patent [ 1 9 1
Vernon e t
a l .
[ 1 1 1 3,907,478
[ 4 5 1 S e p t . 2 3 ,
1 9 7 5
[ 5 4 1
PRODUCTION
or POLYMER
FIBERS
[ 7 5 ]
I n v e n t o r s :
B r i a n
J .
V e r n o n ,
T i m p e r l e y ;
W l a d y s l a w
H .
S k o r o s z e w s k i ,
M a n c h e s t e r ,
b o t h
o f
E n g l a n d
[ 7 3 ] A s s i g n e e : S h e l l
O i l Company, H o u s t o n , T e x .
[ 2 2 ]
F i l e d : J a n .
2 0 , 1 9 7 2
[ 2 1 ] A p p l . N o . : 2 1 9 , 4 0 7
R e l a t e d
US.
A p p l i c a t i o n D a t a
[ 6 2 ] D i v i s i o n
o f
S e r . N o . 8 1 4 , 7 6 8 , A p r i l 9 ,
1 9 6 9 ,
P a t . N o .
3 , 6 7 2 , 0 1 3 . ‘
[ 3 0 ]
F o r e i g n A p p l i c at i o n
P r i o r i t y D a t a
Apr. 1 0 , 1968 United
Kingdo m . . . . . . . . . . . .
. . 17237/68
[ 5 2 ]
US. Cl
. . . . . . . . . . . . . . . . . . . . . . . . . .
425/367; 425/327
[51] Int.
Cl.2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . .
. . B29D 7/22
[58] F i e l d
o f Search
. . . . . . . . . .
425/325, 327, 328,
365,
4 2 5 / 3 6 6 ,
3 6 7 , 3 7 4 ,
4 7 1 ; 2 6 4 / D I G .
8
[56]
References Cited
UNITED STATES PATENTS
l/1956
Annesser . . . . . . . . . . . . . . . . . .
. .
264/D1G.
47
9 / 1 9 6 4 L e m e l s o n . . . . .
1 0 / 1 9 6 7
2 , 7 2 8 , 9 5 0
3 , 1 4 6 , 4 9 2
3 , 3 4 8 , 2 6 4
Rice et al
. . . . . . . . . . . . . . . . . . . . . . .
425/327 x
3 , 5 0 0 , 6 2 7
3 , 5 1 5 , 3 2 5
3 / 1 9 7 0
6 / 1 9 7 0
Kim . . . . . . . . . . . . . . . . . . . . . . . . . . . 264/D1G. 47
Kalwaites . . . . . . . . . . . . . . . . . . . ,
264/D1G.
47
P r i m a r y Examiner-Robert D . B a l d w i n
A t t o r n e y ,
A g e n t , o r
Firm—Martin S . B a e r ;
Howard
W.
Haworth
[ 5 7 ]
ABSTRACT
S y n t h e t i c
f i b e r s ,
s u c h a s p o l y p r o p y l e n e ? b e r s , a r e
manufactured i n a form i n which t h e f i b e r s a r e of r e g
u l a r d i m e n s i o n s a n d s u b s t an t i a l l y f r e e f r o m
w h i s k e r y
appendant ? b r i l s , b y a
c o n t r o l l e d
? b r i l l a t i o n method
which
c o m p r i s e s
i m p r e s s i n g
i n a
web o f
t h e
polymer
c o m p o s i t i o n
a t
a t e m p e r a t u r e above i t s c r y s t a l l i n e
m e l t i n g
p o i n t
a p l u r a l i t y o f g r o o v e s d i s p o s e d i n
c l o s e
b u t sp a c e d - a p a r t
r e l a t i o n s h i p
t o
t h e l o n g i t u d i n a l d i r e c
t i o n
o f
t h e web by p a s s i n g
t h e
web a t s a i d t e m p e r a t u r e
b e t w e e n
two r o l l e r s h a v i n g n o n - y i e l d i n g
s u r f a c e s ,
e . g .
s t e e l r o l l e r s , a t l e a s t one o f which
b e a r s
c l o s e l y
s p a c e d , p a r a l l e l s u r f a c e
r i d g e s
e a c h
h a v i n g
i n w a r d l y
d i r e c t e d
s i d e s l e a d i n g t o peaks which a r e rounded o f f
t o a
s m a l l
r a d i u s ,
t h e
s i d e s o f a d j a c e n t r i d g e s f o r m i n g
t r o u g h s ,
c h i l l i n g t h e g r o o v e d w eb , a n d
s u b j e c t i n g t h e
c h i l l e d we b t o a f i b r i l l a t i o n treatment i n c l u d i n g
s t r e t c h i n g
s a i d web t o
o r i e n t t h e
p o l y m e r .
1
C l a i m ,
5 D r a w i n g F i g u r e s
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US
P a t e n t
S e p t . 2 3 , 1 9 7 5
S h e e t 1
o f 2 3,907,478
m0 ;
m w O O m w
0
h m m o
I V A
/ 6 z <5 6 3 5
w > O O m0
Q F E
8/10/2019 US3907478.pdf
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8/10/2019 US3907478.pdf
http://slidepdf.com/reader/full/us3907478pdf 4/8
3 , 9 0 7 , 4 7 8
1
PRODUCTION OF
POLYMER
FIBERS
This
i s a d i v i s i o n
of
a p p l i c a t i o n S e r .
No.
814,768,
? l e d A p r .
9 , 1 9 6 9 , now U . S .
P a t .
N o . 3 , 6 7 2 , 0 1 3 , i s s u e d
June
27, 1972.
The present
i n v e n t i o n
i s
concerned
with
t h e
manu
f a c t u r e o f
s y n t h e t i c
? b e r s , i n c l u d i n g
s t a p l e
? b e r s and
y a r n s
and
w i t h
t h e
machinery
f o r
t h e
manufacture
from
m o l e c u l a r l y - o r i e n t a b l e
o r g a n i c
p o l y m e r s ,
p a r t i c u l a r l y
p o l y o l e ? n s a n d o l e ? n c o p o l y m e r s ,
f o r
e x a m p l e ,
h i g h
d e n s i t y
p o l y e t h y l e n e
a n d
p o l y p r o p y l e n e .
l t i s
known t h a t
m o l e c u l a r l y - o r i e n t a b l e
o r g a n i c p o l y
mers i n t h e form of
?lms
which have been u n i a x i a l l y
o r i e n t e d
b y s t r e t c h i n g c a n u n d e r g o
? b r i l l a t i n g
f r a c t u r e
( h e r e i n
r e f e r r e d t o a s ? b r i l l a t i o n ) a l o n g c l e a v a g e
l i n e s
r u n n i n g i n t h e
d i r e c t i o n o f o r i e n t a t i o n
b u t s p a c e d a p a r t
i n a g e n e r a l l y random
f a s h i o n
i n t h e d i r e c t i o n
a t r i g h t
a n g l e s
t o t h e d i r e c t i o n
of o r i e n t a t i o n . F i b r i l l a t i o n can
b e
i n d u c e d
b y s u b j e c t i n g t h e
u n i a x i a l l y
o r i e n t e d
?lm
t o
mechanical t r e a t m e n t , f o r
e x a m p l e ,
b r u s h i n g o r
a i r
b l a s t
treatment;
such treatment
i s referred
t o herein as
“ ? b r i l l a t i o n treatment .
I t
i s
a l s o known
o
s l i t
or
score
? l m i n t h e
d i r e c t i o n
of
o r i e n t a t i o n
p r i o r t o s a i d
me
c h a n i c a l treatment with
a
view t o promoting b r i l l a t i o n
and o f r e d u c i n g t h e
d e g r e e
o f randomness
i n
t h e
s p a c
i n g
o f s a i d c l e a v a g e l i n e s . I t h a s a l s o
b e e n
p r o p o s e d , i n
U . S . P a t . No. 2,728,950
t o
A n n e s s e r ,
i s s u e d
i n
1 9 5 6 , t o
s c o r e u n s t r e t c h e d o r i e n t a b l e p l a s t i c ? l m Q i l l u s t r a t e d b y
a
9 7 : 3 v i n y l i d e n e
c h l o r i d e a c r y l o n i t r i l e
p o l y m e r ,
b y
p a s s i n g i t
b e t w e e n
a h e a t e d , g r o o v e d s c o r i n g r o l l e r -
- h a v i n g g r o o v e s se p a r a t ed b y s h a r p r i d g e s
w h i c h
s c o r e
o r cut t h e ?l m - - and
a
r e s i l i e n t backing
r o l l .
Although t h e g e n e r a l
c o n c e p t o f
? b r i l l a t i o n h a s
been
known f o r m a n y y e a r s ,
c o n s i d e r a b l e
e f f o r t
h a s
been de
v o t e d ,
and
c o n t i n u e s
t o
be
d e v o t e d ,
by
t h o s e
i n
t h e
a r t
t o
t h e m a n y problems which
a r i s e
when a p p l y i n g t h i s
concept t o t h e
manufacture
of “?ne f i b e r s , ” i . e . ?bers
o f e x t r e m e l y
s m a l l c r o s s - s ec t i o n , f o r example,
5 t o
9 0
d e n i e r ? b e r s , f r o m m o l e c u l a r l y - o r i e n t a b l e o r g a n i c p o l
y m e r s .
i n o r d e r
t o compete w i t h
? b e r s
produced
by
t h e
c o n v e n t i o n a l “ sp i n n e r e t
method,
t h e m a n u f a c t u r e
o f
?ne
? b e r s
b y
? b r i l l a t i o n must b e c a p a b l e o f
y i e l d i n g ?
b e r s
o f a c c e p ta b l e and c o n s i s t e n t
q u a l i t y a t comparable
o r
l o w e r
c o s t and b y
r e l i a b l e
and
p r a c t i c a l t e c h n i q u e s .
I t has
now
been
found,
i n accordance with
t h e pres
e n t
i n v e n t i o n ,
t h a t
?ne ?bers
can
be manufactured
f r o m
m o l e c u l a r l y o r i e n t ab l e o r g a n i c
p o l y m e r s , f o r
e x
a m p l e , p o l y o l e ? n s
a n d
o l e ? n c o p o l y m e r s
( t h e t e r m
“ p o l y m e r ” i n c l u d i n g a p o l y m e r c o m p o s i t i o n )
b y
t h e
c o n t r o l l e d
? b r i l l a t i o n of
a ? l m thereof which has been
pro?led i n c r o s s - s e c t i o n i n
t h e
m anner
d e s c r i b e d
here
i n a f t e r .
The
p r o ? l i n g
i s s u c h a s t o p r o v i d e l o n g i t u d i
n a l l y extending p o r t i o n s
of
t h e ?lm,
which a r e
t h e pre
c u r s o r s o f
t h e
r e q u i r e d ? b e r s , s p a c e d a p a r t b y l o n g i t u
d i n a l l y
e x t e n d i n g p o r t i o n s o f l e s s e r t h i c k n e s s , w h i c h
a r e t h e
p r e c u r s o r s o f
p r e d e t e r m i n e d c l e a v a g e p a t h s
a l o n g which ? b r i l l a t i o n
w i l l
o c c u r . The term “con
t r o l l e d ? b r i l l a t i o n ” i s
used
t o i n d i c a t e a
? b r i l l a t i n g
f r a c
t u r e ( t h e d e s c r i p t i o n “ ? b r i l l a t i n g f r a c t u r e ” i n c l u d i n g
what
can be r e f e r r e d t o a s
“spontaneous s p l i t t i n g ” )
a l o n g
s u c h
p r e d e t e r m i n e d c l e a v a g e p a t h s t o g i v e
s h a r p l y
de?ned
? b e r s
s u b s t a n t i a l l y f r e e
from “ w h i s
k e r y ”
appendant
? b r i l s . The
term “ c o n t r o l l e d ? b r i l l a
t i o n ” i s used h e r e i n
t o
provide a c o n t r a s t with
r a n d o m
? b r i l l a t i o n
which occurs
i n
a l o n g i t u d i n a l d i r e c t i o n
but
n o t
a l o n g
p r e d e t e r m i n e d c l e a v a g e p a t h s ; i n random ?
b r i l l a t i o n , s u c h
appendant ? b r i l s t e n d t o b e
formed
e v e n
when
t h e f i l m i s s c o r e d o r o u t
p r i o r
t o ? b r i l l a t i o n .
1 0
3 O
40
55
65
2
The
p r e s e n t i n v e n t i o n
i s
o f p a r t i c u l a r i n t e r e s t
f o r
t h e
manufacture of ?ne
polypropylene ? b e r s , f o r
which
a p ~
p r e c i a b l e p o t e n t i a l o u t l e t s h a v e
become a p p a r e n t i n
r e
c e n t
y e a r s i n t h e
t e x t i l e i n d u s t r y ,
f o r e x a m p l e ,
f o r
c a r
p e t
manufacture,
b u t i t i s n o t l i m i t e d t h er e t o ; f o r e x a m
p l e ,
t h e n y l o n s and h i g h d e n s i t y p o l y e t h y l e n e a r e a l t e r
n a t i v e
m o l e c u l ar l y o r i e n ta b l e o r g a n i c
p o l y m e r s
f r o m
which ?ne ? b e r s
c a n
b e m a n u f a c t u r e d b y
t h e
p r o c e s s
o f t h e
p r e s e n t i n v e n t i o n .
According
t o one a s p e c t of
t h e
p r e s e n t i n v e n t i o n , a
p r o c e s s f o r t h e manufacture
of
s y n t h e t i c ?bers
c o m
p r i s e s
b r i n g i n g
a
s h e e t - l i k e mass of
a m o l e c u l a r l y ~
o r i e n t a b l e
o r g a n i c polymer c o m p o s i t i o n
a t
a
tempera
t u r e a b o v e
t h e
c r y s t a l l i n e m e l t i n g p o i n t o f t h e p o l y m e r
i n t o p r e s s u r e contact with a pro?ling
element
t o form
a p r o ? l e d p o l y m e r
web
h a v i n g a
p l u r a l i t y o f l o n g i t u d i
n a l g r o o v e s
d i s p o s e d
i n
c l o s e
b u t sp a c e d - a p a r t
r e l a t i o n
s h i p
i n a t l e a s t one s u r f a c e t h e r e o f , c h i l l i n g
t h e
p r o ? l e d
web
d u r i n g a n d / o r
a f t e r
c o n t a c t w i t h s a i d p r o ? l i n g
e l e
ment
t o
a
temperature
below t h e c r y s t a l l i n e
m e l t i n g
p o i n t o f
t h e p o l y m e r a n d
s t r e t c h i n g
t h e
c h i l l e d ,
p r o ? l e d
w e b
t o
e f f e c t o r i e n t a t i o n t h e r e o f ,
t h e
c h i l l e d
w e b
b e i n g
s u b j e c t e d r d u r i n g a n d / o r a f t e r
s t r e t c h i n g
t o c o n d i t i o n s
r e s u l t i n g i n
a
c o n t r o l l e d ? b r i l l a t i o n thereof t o form
b e r s .
S a i d
p r o ? l i n g
e l e m e n t h a s
a
p l u r a l i t y o f c l o s e l y
s p a c e d , p a r a l l e l
s u r f a c e
r i d g e s
e a c h h a v i n g
i n w a r d l y d i
r e c t e d s i d e s l e a d i n g t o
a
p e a k , t h e s i d e s o f a d j a c e n t
r i d g e s f o r m
t r o u g h s , h a v i n g , f o r e x a m p l e , c o n c a v e l y
s h a p e d ‘ b o t t o m s .
U s u a l l y t h e
s h e e t - l i k e mass o f polymer w i l l b e o f web
form,
but
one
mode of p r a c t i c i n g t h e i n v e n t i o n com
p r i s e s t h e
s i m u l t a n e o u s f o r m a t i o n o f t h e
r e q u i r e d
web
f o r m d u r i n g t h e
p r o ? l i n g
o p e r a t i o n . The t e m p e r a t u r e
o f
t h e
p o l y m e r
i m m e d i a t e l y
p r i o r t o
b e i n g
b r o u g h t
i n t o
pressure contact with t h e pro?ling element
can
be be
tween t h e c r y s t a l l i n e m e l t i n g
p o i n t
o f
t h e poly mer and
150°C
above i t , f o r e x a m p l e , between about 1 5 0 ° and
3 0 0 ° C f o r
p o l y p r o p y l e n e .
While
t h e c o n t a c t
p r e s s u r e
r e f e r r e d t o
should b e l e s s
than t h a t which
would
cause
i n c i s i o n
o f t h e web d u r i n g p r o ? l i n g ,
t h e
p r e s s u r e s h o u l d
be s u f ? c i e n t t o e n s u r e t h a t t h e grooved p o r t i o n s o f t h e
p r o ? l e d web
a r e s i g n i ? c a n t l y t h i n n e r t h a n t h e “humps
between
t h e grooves
t h e r e o f .
The
b u m ps
a r e
formed by
p o l y m e r ?owing
i n t o
a n d
? l l i n g
t h e
t r o u g h s
b e t w e e n
a d j a c e n t r i d g e s
o f t h e
p r o ? l i n g e l e m e n t ;
t h e c o n t a c t
p r e s s u r e should
be adequate t o ensure
t h a t t h i s t a k e s
p l a c e . To
i l l u s t r a t e
t h e o r d e r o f p r e s s u r e
r e q u i r e d
t o e f
f e c t t h e
d e s i r e d
c o n t a c t w i t h t h e p r o ? l i n g element i t
can be
s t a t e d t h a t
good r e s u l t s have been obtained w i t h
c o n t a c t
p r e s s u r e s
i n e x c e s s of about 5 0 0
pounds
per
s q u a r e i n c h , t h e r e q u i r e d p r e s s u r e b e i n g r e a d i l y d e t e r
mined
b y
t r i a l
on
t h e b a s i s t h a t t h e contact
p r e s s u r e
s h o u l d be s u f ? c i e n t
t o
form a pro?led web capable of
u n d e r g o i n g c o n t r o l l e d ? b r i l l a t i o n .
The
p r e s e n t
i n v e n t i o n a l s o i i n c l u d e s t h e r e s u l t i n g
s y n
t h e t i c ? b e r s and s t a p l e ? b e r s , y a r n s , and t e x t i l e g o o d s ,
r o p e s
and
o t h e r
c o r d a g e m a de
t h e r e f r o m .
According
t o
a
f u r t h e r
aspect of
the
present inven
t i o n , machinery s u i t a b l e f o r u s e
i n
t h e manufacture
o f
s y n t h e t i c
? b e r s c o m p r i s e s a w e b ~ p r o ? l i n g
u n i t and
means
f o r u n i a x i a l l y
s t r e t c h i n g
a
p r o ? l e d
polymer
web
from s a i d p r o ? l i n g
u n i t
and f o r s u b j e c t i n g
t h e s t r e t c h e d
w e b t o
a
? b r i l l a t i o n t r e a t m e n t , s a i d web-pro?ling u n i t
c o m p r i s i n g
‘ a p r o ? l i n g e l e m e n t h a v i n g a
p l u r a l i t y
o f
c l o s e l y - s p a c e d , ( p a r a l l e l
s u r f a c e
r i d g e s , e a c h h a v i n g i n
w a r d l y
d i r e c t e d
s i d e s
l e a d i n g t o
a
peak and t h e
s i d e s o f
a d j a c e n t
r i d g e s
f o r m i n g
t r o u g h s ,
f o r e x a m p l e ,
h a v i n g
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3 .
c o n c a v e - l y - s h a p e d . b o t t o m s ,
and means ‘ f o r e f f e c t i n g
pressure
contact between
a
m o v i n g f s h e e t i l i k e
mass
of
p o l y m e r a t ?
a , t e m p e r a t u r e a b o v e f i t s c r y s t a l l i n e y m e l t i n g '
p o i n t - a n d ‘ s a i d ,
p r o ? l i n g e l e m e n t . P r e f e r a b l y s a i d p r o ? l
i n g
elem'entcomprisesa r i d g e d r o l l e r
o r .
thelike
and
.
s a i d
means
f o r e f f e c t i n g p r e s s u r e , contact
comprises
a
f u r t h e r
r o l l e r
o r
‘ t h e
l i k e ,
t h e i r o l l e r s
v o r .
the
l i k e ‘
being
b r o u g h t t o g e t h e r - t o - f o r m , . a n i p , t h r o u g h w h i c h - t h e
s h e e t - l i k e
mass
of
polymer can be p a s s e d , r a n d
d r i v i n g
means o r
. r o t a t i n g t h e
ridged r o l l e r or the l i k e .
Ina
pre-
f e r r e d a r r a n g e m e n t , a r i d g e d r o l l e r i s mounted
f o r r o t a
t i o n
a b o u t . a ?xed a x i s andmeans, f o r e x a m p l e , a
hy
d r a u l i c o r pneumatic
mechanism, a r e
provided f o r - b i a s
i n g t h e o t h e r ,
r o l l e r
towards t h e
r i d g e d r o l l e r t o e f f e c t
the required
pressurecontact.
-The
present ‘ i n v e n t i o n a l s o ‘ i n c l u d e s
[ t h e
above
described w e b pro?ling
u n i t -
per s e ;
, s u c h
a u n i t can be
used i n
combination
‘ w i t h ‘ c o n v e n t i o n a l i n - l i n e v s t r e t c h
i n g
e q u i p m e n t l a n d g , i f
n e c e s s a r y ,
w i t h -
any known or
Suitable ?brillating
equipment.
- _
> Y
> . - :
v
= > A c c o r d i n g h t o . a . f u r t h e r - a s p e c t of t h e present inven
t i o n , a
w e b - p r o ? l i n g u n i t comprisesapair
o f
cooperat
i n g r o t a t a b l e r o l l e r s o r
t h e l i k e h a v i n g n o n - y i e l d i n g ' s u r
f a c e s , a t
leastwone
o f - s a i d - r o l l e r s
or
t h e .
l i k e
being
a d a p t e d 1 t o
b e d r i v e n
and
h a v i n g a p l u r a l i t y o f c l o s e l y
s p a c e d , p a r a l l e l , s u r f a c e r i d g e s e a c h
h a v i n g
i n w a r d l y
d i r e c t e d
s i d e s l e a d i n g
t o a peak
and t h e s i d e s o f
a d j a
c e n t r i d g e s f o r m i n g t r o u g h s , , f o r e x a m p l e , h a v i n g
c o n
c a v e l y - s h a p e d b o t t o m s , and means
f o r b i a s i n g s a i d r o l
l e r s - o r
the
l i k e
towards
one another t o form a ‘ n i p .
Y
v W h i l e t h e
p r o c e s s o f t h e p r e s e n t i n v e n t i o n
i s
p r e f e r a
b l y c a r r i e d o u t u s i n g a s t h e - p r o ? l i n g e l e m e n t a r i d g e d .
r o l l e r , f o r e x a m p l e , a d r u m and t h e w e b v i s ‘ p r e s s e d
a g a i n s t - t h e
r i d g e d
r o l l e r
b y
a
p l a i n ,
: i . e - .
. u n r i d g ’ e d ,
r o l l e r
( h e r e - i n r e f e r r e d t o
a s
a
“backing r o l l e r ” ) , one
may
l s o
employ o t h e r f o r m s o f
p r o ? l i n g e l e m e n t s,
f o r e x a m p l e ,
a n -
e n d l e s s b e l t h a v i n g t h e r e q u i s i t e s u r f a c e r i d g e s . The
r i d g e d
r o l l e r o r
other-pro?ling
element
must
have
a
h a r d , n o n - y i e l d i n g s u r f a c e, f o r e x a m p l e ,
o f
s t e e l ;
t h e
b a c k i n g v r o l l e r or other
backing element
a l s o
has
anon
y i e l d i n g
s u r f a c e i n
viewof t h e
p r e s s u r e s
i n v o l v e d i n
t h e
p r o ? l i n g
o p e r a t i o n ' a n d t h e
n e e d
f o r a c c u r a t e p r o ? l i n g
o f t h e
pol y mer
web.
In a‘conv 'enientarrangemen t. a
r i d g e d
, r o l l e r , - which
i s -
r o t a t e d by s u i t a b l e - d r i v i n g
means,
f o r
example, an e l e c t r i c motor,
i s
disposed
a l o n g s i d e a b a c k i n g r o l l e r , , p r o v - i s i o n
b e i n g
ma de o r - a c
c u r a t e l y p o s i t i o n i n g one
r o l l e r
w i t h r e s p e c t
t o
t h e other
t o ensure t h a t
t h e i r a x e s
a r e - t r u l y p a r a l l e l
during
opera
t i o n of t h e p r o c e s s . Such p o s i t i o n i n g can b e ‘ achieved
b y
means-
of ' a h y d r a u l i c
or
pneumatic
mechanism
which
a l s o . p r o v i d e s t h e r e q u i r e d contact p r e s s u r e o n ,
the hot web during-pro?ling.» . .
The
w e b t o
be pro?led
can
be formed,
f o r
example,
by
conventional
s l o t - d i e e x t r u s i o n
a s a ? r s t
s t e p i n ' t h e
processof
h e
p r e s e n t ‘ i n v e n t i o n , t h e d i s p o s i t i o n o f t h e
e x t r u s i o n o r i ? c e w i t h r e s p e c t
t o
t h e r i d g e d r o l l e r b e i n g ,
f o r e x a m p l e , s u c h t h a t t h e h o t , e x t r u d e d w e b f l o w s
d o w n w a r d l y
i n t o ‘ t h e n i p
f o r m e d
b e t w e e n
t h e
r i d g e d
r o l l e r -
and t h e
backing o l l e r , a l t h o u g h
i t
c o u l d a l s o
?ow
downwardly
onto
e i t h e r
r o l l e r . I n t h i s w a y ‘ t h e extruded
w e b , which
a t
t h e t e m p ' e r a t u r e s
i n v o l v e d h a s i n s u f ?
c i e n t s t r e n g t h t o w i t h s ta n d ‘ e v e n t h e
t e n s i o n s
i n
volved
i n ' p u l l i n g
a w e b over r o l l s or
o f f
a r e e l , can b e
h a n d l e d
w i t h o u t ' d i f ? c u l t y . I t w i l l
b e
a p p r e c i a t e d t h at
p r e h e a t i n g , a p r e f o r m e d ‘ web o f p o l y m e r
t o q a b o v e - i t s
c r y s t a l l i n e ' r n e l t i n g p o i n t
p r i o r
t o
c o n t a c t i n g
. t h e r i d g e d
r o l l e r
would b e ‘ a d i f ? c u l t o p e r a t i o n i n p r a c t i c e; v c a r r y
' 2 0
25
35
4 5
55
60
65
4
ing o u t t h e g p r e s e n t r p r o e e s s g i i n
t h i s w a y , - a l t h o u g h n o t
n e c e s s ar i l y e x c l u d e d , i s p r e f e r a b l y a v o i d e d . Atthe t e m
p e r a t u r e o f
t h e
web when t ’
c o n t a c ts t h e r i d g e d r o l l e r
t h e
s e l e c t e d groove
pro?le
can be a c c u r a t e l y
repro
d u c e d i n t h e i m p r e s s e d
w e b ,
p r o v i d e d j t h e n e c e s s a r y
c o n t a c t ,
p r e s s u r e
i s
a p p l i e d
t o , - . t h e web
a s
i n d i c a t e d
a b o v e r A c c u r a t e
p r o ? l i n g
i s
i m p o r t a n t
f r o m
t h e p o i n t
v o f
v i e w
o f
a c h i e v i n g u n i f o r m i t y i n
t h e
r e s u l t i n g f i n e - ?
bers.
As
‘ s o o n ,
a s
t h e »
required ; grooves h a v e
been
formed i n t h e w e b , - t h e ‘ r e s u l t i n g groove
p r o ? l e
can be
‘ ? s e t ” a n d
t h e
, w e b . r e n d e r e d h a n d l e a b l e b y .
t h e ,
c h i l l i n g
o p e r a t i o n . C o n s e q u e n t l y , r a p i d c h i l l i n g o f t h e h o t web
t o
. b e l o w i t s c r y s t a l l i n e
m e l t i n g p o i n t ;
s
p r e f e r a b l y ,
com
p l e t e d
, a s - s o o n a s
p o s s i b l e a f t e r t h e r e q u i s i t e
g r o o v e s
have been f o r m e d t h e r e i n . The r e q u i r e d c h i l l i n g c a n b e
o b t a i n ed , f o r ' e x a m p l e ,
b y t h e c i r c u l a t i o n
o f
a
c o o l i n g
h e a t - t r a n s f e r - J i q u i d , f o r
e x a m p l e , - w a t e r ,
t h r o u g h t h e
r i d g e d v r o l l e r a n d / o r t h r o u g h t h e , b a c k i n g ‘
r o l l e r .
B o t h
r o l l e r s
p r e f e r a b l y
h a v e p r o v i s i o n f o r
t h e
c i r c u l a t i o n
o f
: h e a n t r a n s f e r f l u i d t h e r e t h r o u g h s o
t h a t
t h e s u r f a c e s o f
t h e - , r o l l e r s l c a n b e
m a i n t a i n e d
a t q a n y ; d e s i r e d
tempera
t u r e
d u r i n g o p e r a ti o n
o f , t h e _ p r o c e s s . = T h i s o p e n s u p t h e
p o s s i b i l i t y
o f e f f e c t i n g
a d i f f e r e n t i a l s u r f a c e c o o l i n g o f
thepro?led
w e b
which,
i n
some,
c a s e s , , m a y be used t o
. i m p a r t s e l f - c r i m p i n g p r o p e r t i e s t o t h e r e s u l t i n g ? b e r s .
The web
can be
p r o f i l e d ,
i . e _ .
impressed
w i t h
s a i d
grooves,
oneither
one or both
of t s
s u r f a c e s .
I n
t h e , l a t
t e r c a s e two r i d g e d r o l l e r s ( o r o t h e r p r o ? l i n g
e l e m e n t s )
can ‘ b e u s e d ,
e a c h .
of which
i s
provided with t h e neces
s a r y - s u r f a c e
r i d g e s
o f i d e n t i c a l
p i t c h a n d u s u a l l y
a l s o
i d e n t i c a l p r o ? l e s . . - , For e x a m p l e ,
t h e :
h o t w e b can be
p a s s e d
t h r o u g h
t h e r n i p v f o r m e d v b e t w e e n t w o : r i d g e d r o l
l e r s
which
a r e
a c c u r a t e l y
p o s i t i o n e d w i t h
r e s p e c t
t o t h e
oneanother;
o
t h a t t h e
p e a k s
o f
t h e r e s p e c t i v e r i d g e s
i m p r e s s t h e web i n e x a c t l y o p p o s e d ‘ p o s i t i o n s .
How
e v e r ,
t o a v o i d
u n n e c e s s a r y
c o m p l i c a t i o n ' i t i s p r e f e r a b l e
t o
form
grooves i n o n l y
one s u r f a c e - o f the w e b
u n l e s s
?bers
o f p a r t i c u l a r
c r o s s s e c t i o n ‘
which
can
o n l y
be
ob
t a i n e d b y g r o o v i n g b o t h s u r f a c e s - a r e r e q u i r e d . - U s u a l l y
?bers
of
s u i t a b l e
c r o s s - s e c t i o n totmeet end-use
r e q u i r e
ments
a r e r e a d i l y ' o b t a i n a b l e - b y
grooving
only one
s u r
faceof theweb .v
» -
I ' '
The web
a n ‘ b e
of
any convenient width and i n gen
e r a l
t h e
w i d t h
o f
t h e
web i l l be
s u b j e c t o n l y ' t o
any
l i m
i t a t i o n s
i m p o s e d
t h e r e o n b y
t h e
z - e x t r u s i o n p r o c e s s b y
me ans of w h i c h i t i s
produced.
I t i s a
p a r t i c u l a r
advan
t a g e
o f
t h e
p r e s e n t
i n v e n t i o n
t h a t
webs
o f
q u i t e l a r g e
w i d t h s , forexample,
up
t o 1
y a r d
c a n ‘
be converted i n t o
a l a r g e
number f
? b e r s ,
f o r
example,
upto
1 2 , 0 0 0 ,
de
pending upon
t h e
we b
w i d t h - a n d t h e d e n i e r
o f
t h e ? b e r .
I n
t h i s way-a l a r g e r
?beroutput
can be a c h i e v e d from
a s i n g l e manufacturing l i n e comprising
only
one
we b
p r o ? l i n g
u n i t .
The h o t
web f e d
t o
t h e
p r o ? l i n g
element
can have
a t h i c k n e s s of between
25
and 200 m i c r o n s ,
although we bs of other thicknessare not excluded.
I n t h e p r o c e s s o f t h e
p r e s e n t ‘
i n v e n t i o n ,
t h e
c h i l l e d ,
p r o ? l e d
w e b , l e a v i n g t h e n i p
i s s t r e t c h e d ; v f o r e x a m ' p l e ,
t e n f o l d ,
u s i n g s u i t a b l e
s t r e t c h i n g
e q u i p m e n t ‘ k n o w n ‘ t o
t h o s e s k i l l e d
i n
t h e
a r t ,
w i t h t h e r e s u l t
t h a t
t h e polymer
comprised
t h e r e i n
i s o r i e n t e d a n d ' t h e c r o s s - s e c t i o n a l
a r e a o f
t h e
we b
i s
reduced
c o r r e s p o n d i n g l y .
S t r e t c h i n g
can b e ' c a r r ‘ i e d o u t
u s i n g , f o r
example, a - p a i r t o f
Godet
r o l l - s e t s
w i t h
a h o t a i r oven d i s p o s e d between them
t h r o u g h
which
t h e r w e b u n d e r
t e n s i o n
p a s s e ' s f T h e
s e c
o n d Godet r o l l s e t i s r o t a t e d f a s t e r ' t h a n ‘ t h e
? r s t t o
an
e x t e n t which p r o v i d e s ' t h e ‘
d e s i r e d
d e g r e e
o f
d r a w ,
i . e .
t h e s t r e t c h .
r a t i o . T y p i c a l r a t i o s w h i c h i c a n b e e m p l o y e d
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“ 3 1 , 9 0 7 , 4 7 8
‘ f o r
polypropylene
are between 5 : ‘ a n d 1 2 : 1
or
more;
‘ t h e
h o t
a i r o v e n c a n ' b e ‘ o p e r a t e d ata t e m p e r a t u r e o f
t h e
order
of 1 4 0 ‘ ? t o l50°C.K
A s a r e s u l t
o f v
t h e
pro?le
of t h e s t r e t c h e d web a con—
. t r o l l e d ?brillationthereof. w i l l
occur
under
s u i t a b l e
c o n d i t i o n s .
I n
f a c t , - i t
i s
a
p a r t i c u l a r
advantage o f t h e
p r e s e n t i n v e n t i o n
t h a t
s u c h
c o n d i t i o n s
i n
m a n y
i n
s t a n c e s c a n b e
p r o v i d e d
b y ‘ t h e m e c h a n i c a l
h a n d l i n g
o f
t h e web d u r i n g t h e s t r e t c h i n g
‘ o p e r a t i o n . I n
many i n
s t a n c e s , f o r e x a m p l e , - w i t h p o l y p r o p y l e n e w e b s , t h e
p r o ? l e d web u n d e r g o e s a s p o n t a n e o u s b r e a k d o w n i n t o
? l a m e n t s
d u r i n g b p a ss ag e t h r o u g h t h e
s e c o n d
G o d e t
‘ u n i t ; i n f a c t some
s p l i t t i n g
c a n occur n
t h e ‘
h o t
a i r
o v e n .
I f n e c e s s a r y ,
h o w e v e r ,
t h e c o n d i t i o n s u n d e r
w h i c h
c o n ~
t r o l l ed ? b r i l l a t i o n o f r i t h e c h i l l e d we b t a k e s
p l a c e a r e
p r o v i d e d ‘ b y
s u b j e c t i n g - t h e
w e b ,
a f t e r ‘ s t r e t c h i n g ,
t o ?
b r i l l a t i o n t r e a t m e n t , w h i c h ‘
can be
c a r r i e d
out i n any
known
o f
s u i t a b l e
manner. For e x a m p l e , t w i s t i n g can
b e
u t i l i z e d , ‘ u s i n ' g ' a
c o n v e n t i o n a l
h e a v y
d u t y
t w i s t i n g
machine, such a s
a s i s a l
t y p e
t w i s t i n g m a c h i n e . p r e f e r a
blyJh‘oweverQsuch
? b r i l l a t i o n
‘ t r e a t m e n t
when
t
i s
r e
quired
i s
effected b y means of an
a i r
b l a s t treatment ef
f e c t e d b y p a s s i n g t h e , s t r e t c h e d web
t h r o u g h a n
e l o n
g a t e d
p a s s a g e
o f
r e s t r i c t e d
c r o s s - s e c t i o n t h r o u g h which
acurrent o f
a i r f l o w s
a t a h i g h v e l o c i t y i n
t h e
d i r e c t i o n
o f ,movement
o f t h e
web. F o r , example, good
r e s u l t s
have
been obtained
b y
: f e e d i n g
t h e
s t r e t c h e d w e b
t h r o u g h
a n
a s p i r a t o r h f o r
e x a m p l e , t h e
d e v i c e c o m
monly
known asa “ w a s t e c o l l e c t o r ” , o p e r a t e d a t a b o u t
8 0 . pounds
p e r
s q u a r e , i n c h ‘ ( g a u g e )
p r e s s u r e .
I n t h i s
w a y o n e , c a n a v o i d ‘ t h e n e e d f o r r e e l i n g - u p b e t w e e n
s t r e t c h i n g
a n d ? b r i l l a t i o n t r e a t m e n t s i n c e t h e a i r b l a s t
? b r i l l a t o r c a n o p e r a t e ‘ e f f e c t i v e l y
a t
t h r o u g h p u t s p e e d s
e q u a l
t o t h o s e “
a t
which
t h e
s t r e t c h e d
?lm
l e a v e s
t h e
s e c o n d G o d e t r o l l s e t ; s u c h s p e e d s
c a n b e , f o r
e x a m p l e ,
200 t o 400 f e e t o r more
p e r
m i n u t e .
The s t r e t c h e d
w e b ,
upon
? b r i l l a t i o n ,
y i e l d s a
l a r g e
p l u r a l i t y
o f
‘ ? n e ? b e r s , ‘
each o f
which
i s
formed
by a
“hump” i n t h e s tr e t c h e d p r o ? l e d w e b .
Although
t h e d e s c r i p t i o n
h e r e i n r e f e r s
m a i n l y ‘ t o
con
t i n u o u s
f i b e r s and y a r n s formed t h e r e f r o m , i t
w i l l
be
understood t h a t t h e p r e s e n t - i n v e n t i o n
can
a l s o
be used
f o r
t h e
m a n u f a c t u r e o f s t a p l e
? b e r s ,
f o r e x a m p l e ,
by
chopping i n t o
s h o r t
l e n g t h s t h e c o n t i n u o u s ? b e r s
formed
i n t h e
? b r i l l a t i o n
s t a g e ; t h e s e
s t a p l e
?bers
can
t h e n
b e p r o c e s s ed b y ‘ c o n v e n t i o n a l t e x t i l e h a n d l i n g
techniques.
I f d e s i r e d , t h e s h e e t - l i k e mass of poly mer f e d t o
t h e
p r o ? l i n g
u n i t
c a n
c o m p r i s e
a p l u r a l i t y
o f
hot‘webs
which
a r e
u n i t e d
d u r i n g
t h e
p r o ? l i n g o p e r a t i o n .
For ex
a m p l e , two
such
webs can be formed by s l i t - d i e e x t r u
‘ s i o n f r o m p o l y m e r s o f d i f f e r e n t c h a r a c t e r i s t i c s , t h e y
ma y
i f f e r , f o r e x a m p l e , i n m o l e c u l a r w e i g h t o r chemi
‘ c a l n a t u r e .
The
r e s u l t i n g hot webs can be f e d through
t h e n i p between t h e r i d g e d
r o l l e r and
t h e b a c k i n g
r o l l e r
t o become u n i t e d i n t o ’ a s i n g l e bi-component web and
s i m u l t a n e o u s l y p r o ? l e d i n a c c o r d a n c e
w i t h t h e
p r e s e n t
i n v e n t i o n . A l t e r n a ti v e l y , s a i d
i n d i v i d u a l webs can
b e
b r o u g h t t o g e t h e r t o form a h o t , bi-component
web
p r i o r t o
c o n t a c t i n g t h e r i d g e d r o l l e r , f o r e x a m p l e ,
b y
employing
a
m u l t i p l e
o r i ? c e
d i e
o r
by
b r i n g i n g
s e p a r a t e
6
clude the
case i n
which
the peak.
i s rounded o f f . t o
a
20
25
30
35
45
60
melts of the
two polymers
together i n the die-head
i n
a r e g i o n l o c a t ed
j u s t
b e f o r e t h e e x t r u s i o n o r i ? c e .
P r e f e r a b l y t h e ,
r i d g e s o f t h e p r o ? l i n g e l em e n t ,
f o r
e x
a m p l e , a
r i d g e d r o l l e r ,
s h o u l d h a v e t h e s o r t o f p r o ? l e
t h a t c a n
b e s t
b e d e s c r i b e d assharp
p e a k s ,
b u t i t i s t o
b e u n d e r s t o o d t h a t t h e word
“ s h a r p ”
i s i n t e n d e d ; t o
i n
65
s m a l l
r a d i u s o r i n
which
t h e
t i p
of t h e peak
i n c l u d e s
a
s m a l l
? a t
p o r t i o n .
v T h e
p r o ? l e o f the r i d g e s s h o u l d b e
such t h a t t h e h o t ‘ w e b i s g r o o v e d , i . e .
impressed
o r em
b o s s e d , t o g i v e a
c r o s s - s e c t i o n a l p r o ? l e
comprising a
l a r g e
p l u r a l i t y
o f s p a c e d - ap a r t
“ h u m p s , ”
e a c h o f s u i t
a b l e “ ? b e r - f o r m i n g ”
p r o ? l e ,
j o i n e d
t o g e t h e r b y
n a r r o w
“ t r o u g h s ”
h a v i n g
a
t h i c k n e s s
which m a y b e o f t h e o r d e r
of about
I
/ 10
t o
1 / 2 0 o r even l e s s o f t h a t of t h e
o r i g i n a l
web. The h u m ps c o n s t i t u t e t h e
p r e c u r s o r s o f
t h e u l t i
mate ?bers and t h e t r o u g h s c o n s t i t u t e t h e p r e c u r s o r s of
t h e p r e d e t e r m i n e d
c l e a v a g e
p a t h s
a l o n g
w h i c h
. t h e
s t r e t c h e d
we b w i l l s p l i t
d u r i n g t h e c o n t r o l l e d
? b r i l l a
t i o n t h e r e o f . The ultimate ?ne ?bers can have a denier
of
5 up t o
9 0 ;
such
?bers
have e x c e l l e n t handle
and
ap
p e a r a n c e , and
a
good
t e n a c i t y ,
f o r example
7
grams p e r
denier.
_
I n
t h e c a s e
o f a r i d g e d r o l l e r , t h e r i d g e s on t h e p e r i p h
e r y of t h e r i d g e d r o l l e r can have a p i t c h
l y i n g
w i t h i n t h e
range 0.003 t o 0.050 ( i n c h e s and t h e depth of t h e
. t r o u g h s
between
a d j a c e n t
r i d g e s
c a n
l i e
w i t h i n
t h e
range 0.002 t o 0 . 0 2
i n c h e s .
P r e f e r a b l y
t h e
r i d g e s e x
t e n d w i t h o u t
i n t e r r u p t i o n r o u n d
t h e p e r i p h e r y o f t h e
r o l l e r , b u t
i t
i s
a l s o
p o s s i b l e
f o r
each r i d g e
t o b e
d i v i d e d
l e n g t h w i s e
i n t o two
o r more s e c t i o n s b y p l a i n ,
i . e . un
r i d g e d ,
p o r t i o n s o f
t h e r o l l e r
s u r f a c e
which
a r e
s t a g
gered with
respect
t o one another a c r o s s th e width
of
t h e r o l l e r s .
The l a t t e r arrangement m a y
have
advan
t a g e s
when, f o r example, i t
i s
d e s i r e d t o form
a yarn
f o r
t w i s ti n g i n t o
twine f o r
use a s such or i n t h e m a n u f a c
t u r e
of
r o p e or other C ordage, s i n c e t h e i n d i v i d u a l ?
b e r s i n t h e
r e s u l t i n g
y a r n w i l l
n o t .
be completely sepa
r a t e d from one a n o t h e r , t h e r e b y i n c r e a si n g t h e s t r e n g t h
of
the
twine.
The present invention
w i l l
now
b e
described with r e f
erence
t o
t h e accompanying drawings i n w h i c h :
F I G . 1
s h o w s
s c h e m a t i c a l l y
t h e
g e n e r a l a r r a n g e m e n t
of
equipment s u i t ab l e f o r u s e i n c a r r y i n g out
t h e
p r e s
e n t
i n v e n t i o n ;
F I G .
2 i l l u s t r a t e s
t h e r i d g e p r o ? l e
o f
t h e r i d g e d r o l l e r
e m p lo y e d
i n t h e
web-pro?ling u n i t
o f FIG. 1 ;
FIG.
3 s a
s i d e
e l e v a t i o n of one form
of
web-pro?ling
u n i t
i n
accordance
w i t h t h e p r e s e n t i n v e n t i o n ;
FIG. 4
i s
a p l a n view of
t h e machine
of
F I G .
3 ; and
F I G . 5
i s a s e c t i o n
through
a p o r t i o n o f a
pro?led
web.
R e f e r r i n g
t o
F I G . 1 , t h e p r o c e s s o f t h e p r e s e n t i n v e n
t i o n
i s
c a r r i e d
outin
two
s u c c e s s i v e
s t a g e s ,
namely
w e b - p r o ? l i n g ( A ) , a n d
s t r e t c h i n g
a n d
? b r i l l a t i o n ( B ) .
I n t h e ? r s t s t ag e ( A ) , a s l o t
d i e
, e x t r u d e r 1 p r o v i d e s a
web 2 o f
m o l e c u l a r l y - o r i e n t a b l e
o r g a n i c polymer com_
p o s i t i o n a t a t e m p e r a t u r e a b o v e i t s c r y s t a l l i n e m e l t i n g
p o i n t ,
which i s f e d
between
t h e n i p formed
between a
r o l l e r 3
h a v i n g
c l o s e l y - s p a c e d , p a r a l l e l
s u r f a c e
r i d g e s
and a smooth- surfaced backing
r o l l e r
4 . Both r o l l e r s 3
and 4 are of t e e l so a s t o provide
non-yielding
surfaces
f o r i m p r e s s i n g t h e d e s i r e d g r o o v e s
i n t o
t h e s u r f a c e of
t h e web 2 w i t h o u t c u t t i n g t h r o u g h
t h e
w e b , t h e l a t t e r
b e i n g a v o i d e d b y
c a r e f u l
p o s i t i o n i n g
o f
b a c k i n g r o l l e r
4 w i t h r e s p e c t t o r i d g e d r o l l e r
3 .
The r e s u l t i n g g r o o v e d
web
'
passes
over
an
i d l e r r o l l e r
5
t o
the
? r s t
r o l l
of
a s t a n d a r d Godet u n i t 6 which i n
o p e r a t i o n p r o v i d e s
t h e
n e c e s s a r y t e n s i o n i n t h e web t o p u l l i t t h r o u g h t h e
n i p
between r o l l e r s
3 and
4 . The web 2 ’ i s p u l l e d from
t h e ? r s t Godet
u n i t
6‘through a s t a n d a r d h e a t i n g oven
7
b y
a
second
Godet
u n i t 8 which runs a t
a higher
speed
than u n i t 6
so
a s t o s t r e t c h the web 2 ' i n t o i t s drawn
8/10/2019 US3907478.pdf
http://slidepdf.com/reader/full/us3907478pdf 7/8
1 3 , 9 0 7 , 4 7 8
7
F o r m
2 . Such s t r e t c h i n g
e f f e c t s
molecular o r i e n t a t i o n
of
t h e w e b 2 ’ and a l s o r e s u l t s i n an appreciable
draw
down of t s c r o s s - s e c t i o n
t o
an
extent‘depending
on the
draw-down r a t i o employed; s u p r i s i n g l y , i n most i n
s t a n c e s c o n t r o l l e d ? b r i l l a t i o n
of t h e
dr a wn- down
w e b
2
occurs
during t h e
mechanical handling
which oc
c u r s
d u r i n g
i t s
p a s s i n g
through
t h e
second
Godet
u n i t
8 ; i n fact such ?brillation
can
s t a r t
within the o v e n 7
i n
‘ w h i c h s t r e t c h i n g
i s
taking p l a c e .
I n
t h i s w a y a
spontane
ous and
complete
d i v i s i o n
of
the
web
n t o
i n d i v i d u a l ?
b e r s , e a c h
o f drawn-down c r o s s - s e c t i o n c o r r e s p o n d i n g
t o t h a t
of
t h e “humps” of t h e
impressed
web, o c c u r s .
However, i f a
complete
d i v i s i o n i s not achieved i n t h i s
way t h e s t r e t c h e d
we b 2
i s p a s s e d
through an
a s p i r a
t o r
shown i n
broken l i n e s
a t
9 i n which ? b r i l l a t i o n
takes
p l a c e o r i s completed.
I n
e i t h e r case t h e r e s u l t i n g yarn
2 ’ of i n d i v i d u a l ?bers i s
reeled-up
on t h e s p o o l
1 0 .
FIG. 2 of t h e drawing shows
on
an enla rged s c a l e the
k i n d
o f r i d g e p r o ? l e o f
r o l l e r
3
which
can be
employed
i n carrying out t h e present
i n v e n t i o n .
A s w i l l
b e seen
from F I G . 2 , t h e c h a r a c t e r i z i n g f e a t u r e s o f t h e p r o ? l e
a r e t h e
p e a k s , t h e
t r i p s o f
which
a r e
o n l y
s l i g h t l y
r a d i
u s e d , and
s e c o n d l y
a ‘ d i m e n s i o n x
o f
t h e
peaks w h i c h ,
w h i l e p r o v i d i n g
f o r
a d e q u a t e
s t r e n g t h ,
r e s u l t s i n t h e
m i n i m u m
“land” between a d j a c e n t “humps” o f t h e
grooved
web 2 ’ , which
l a n d
c o n s t i t u t e s
t h e
p r e c u r s o r
o f t h e p r e d e t e r m i n e d l o n g i t u d i n a l p a t h al o n g w h i c h t h e
g r o o v e d
web i l l
s p l i t
d u r i n g t h e s u b s e q u e n t ? b r i l l a t i o n
treatment.
The
thickness of
t h e
web
' i n
t h i s land
por
t i o n
can be
of
t h e
order
o f , f o r example,
up
t o 1 / 2 0
of
t h a t
of t h e
w e b
b e f o r e g r o o v i n g , and t h e depth o f t h e
grooves i n r i d g e d r o l l e r
3
should be
such
t h a t t h e
ma te
r i a l
o f
t h e
web ?ows i n t o t h e t r o u g h s
o f
t h e r i d g e d
r o l
l e r
3 d u r i n g
t h e
g r o o v i n g
o p e r a t i o n .
I n
g e n e r a l , t h e
d e
n i e r
of t h e
r e s u l t i n g ?bers
w i l l
be
determined
by
t h e
s i z e o f
t h e humps
of we b
2 ’ and t h e degree
of
draw
down which
t a k e s p l a c e
d u r i n g s t r e t c h i n g ; both can be
v a r i e d
w i t h i n
s u f ? c i e n t l y wide l i m i t s
t o
enable ?bers of
an adequately
wide
range of
denier t o b e manufactured
b y t h e ' p r e s e n t p r o c e s s . The a p p e a r a n c e o f one example
of a
t y p i c a l
grooved
w e b
2 '
i s
shown
i n s e c t i o n i n
FIG.
5 .
R e f e r r i n g
t o
FIGS.
3 and
4
o f t h e
accompanying
drawing,
the
pro?ling u n i t c o n s i s t s of a machine com
p r i s i n g a main frame 1 1 c ar r i e d on l e g s
12 upstanding
from a base
1 3 ,
and a
subframe l4
p i v o t a l l y
mounted
on m a i n frame
1 1
a t
p i v o t p o i n t s
1 5 .
Main
frame
1 1
c a r r i e s a s t e e l , r i d g e d
r o l l e r
3 which i s d r i v e n b y
an
e l e c t r i c motor 16 through a b e l t d r i v e
1 7 ,
t h e r o l l e r 3
b e i n g mounted i n r o l l e r
b e a r i n g s
1 8 .
Subframe
14
c a r r i e s
a
s t e e l backing
r o l l e r
4 mounted i n r o l l e r bear
i n g s
1 9 .
Both
r o l l e r s 3 and 4 have p r o v i s i o n
f o r
t h e
c i r
c u l a t i o n of a heat t r a n s f e r ' r n e d i u m
therethrough,
the
h e a t
t r a n s f e r mediu m e n t e r i n g t h r o u g h
i n l e t s
2 0 , 2 1
and
l e a v i n g
t h r o u g h
o u t l e t s 2 2 ,
2 3 . Mov e m e n t o f sub
frame 14
about
i t s
p i v o t
p o i n t s 1 5
i s e f f e c t e d
by two
c o m p r e s s e d
a i r - o p e r a t e d j a c k i n g
c y l i n d e r s 24
a n d 2 5
which a r e p i v o t a l l y anchored
t o
base 13 a t 26 and 2 7 ,
r e s p e c t i v e l y , and which a r e
p i v o t a l l y
attached t o sub
frame
14 a t
28
and
2 9 .
Located
above
p i v o t
p o i n t s 2 8 ,
29
and
‘ s p a n n i n g
between
t h e
two
s i d e p l a t e s 1 4 '
and
14 of subframe
14 i s
a
t o r s i o n bar
3 0
which i s ?x ed
a t one
end t o
s i d e
p l a t e
1 4 ’ .
The
other
end of
the t o r
s i o n
b a r p r o j e c t s w i t h s l i g h t c l e a r a n c e through
a
h o l e ‘
i n
t h e o t h e r s i d e p l a t e 14 t o a l l o w f o r minor d i f f e r
e n c e s i n t h e
r a t e
o f
l i f t
between j a c k i n g c y l i n d e r s ’ 2 4 ,
2 5 . S i d e p l a t e s 14 and 14” of
subframe
14 a r e kept
' 8
a p a r t and i n
a l i g n m e n t
b y t h e b a c k i n g r o l l e r 4 . A n i d l e r
r o l l e r
5
i s provided i n
main
frame
1 1
t o
a s s i s t
i n
t a k i n g
o f f t h e pro?led web t o t h e s t r e t c h i n g l s t a g e .
I n o p e r a t i o n o f
t h e machine
shown i n FIGS. 3 and 4 ,
5 j a c k i n g
c y l i n d e r s 2 4 , 25 a r e o p e r a t e d t o
b r i n g t h e
back
20
25
3 0
35
4 0
4 5
5 0
55
60
65
i n g r o l l e r
4
i n t o
t h e
o p e r a t i v e
p o s i t i o n - i n which i t i s
s l i g h t l y
spaced from r i d g e d r o l l e r 3
t o
an
e x t e n t
de
pending
on the desired
web
t h i c k n e s s . A ot p o l y m er
w e b
s then
extruded
downwardly
i n t o
t h e n i p
between
r o l l e r s 3 and 4 ,
w h i l e
r o l l e r 3 i s
r o t a t e d
by motor 1 6 .
The f r i c t i o n a l e f f e c t o f
t h e
h o t
web p a s s i n g
through
t h e
n i p c a u s e s
r o l l e r
4 ‘ t o t u r n i n an o p p o s i t e
d i r e c t i o n
t o
r o l l e r
3 . A i r p r e s s u r e
i s
t h e n a p p l i e d t o
j a c k i n g c y l i n
d e r s
2 4 , 2 5 , f o r
e x a m p l e , a
p r e s s u r e
o f 8 0 ° — 9 0 ° p s i
(pounds
per square i n c h ) i n t h e c a s e of t h e
machine
used
i n
t h e f o l l o w i n g
s p e c i ? c . e x a m p l e , t o b i a s
t h e
back
i n g
r o l l e r 4
towards r i d g e d r o l l e r
3 s o t h a t t h e
hot
w e b
i s b r o u g h t i n t o p r e s s u r e c o n t a c t w i t h t h e
r i d g e s
t h e r e o f
a n d
t h e r e b y
i m p r e s s e d w i t h
t h e r e q u i r e d
p r o ? l e .
'The
p r e s en t i n v e n t i o n i s i l l u s t r a t e d
by
t h e f o l l o w i n g
e x a m p l e :
EXAMPLE
Polypropylene ?bers of an average d e n i e r o f 30 were
m a d e from
commercial
p o l y p r o p y l e n e o f m e l t i n d e x
3 . 5
u s i n g
m a c h i n e r y c o m p r i s i n g
a
p r o ? l i n g u n i t a s j u s t
d e s c r i b e d
and
c o n v e n t i o n a l
s t r e t c h i n g
e q u i p m e n t . The
p r o ? l i n g
u n i t comprised a d r i v e n s o l i d s t e e l r o l l e r 1 0
i n c h e s
long
and 4 i n c h e s
i n diameter
which
was
pro
v i d e d w i t h 240
p a r a l l e l s u r f a c e
r i d g e s
e x t e n d i n g
o v e r
a
6
i n c h
l e n g t h
o f i t s
s u r f a c e .
The r i d g e s
were ma de
b y
p r e c i s i o n g r i n d i n g '
t o
a 40 T P I v ( t h r e a d s p e r i n c h ) S t a n
d a r d Whitworth f o r m , t h e
r i d g e s
h a v i n g a p i t c h o f
0.0125 i n c h , a
depth
o f
0.0077
i n c h
and'an i n c l u s i v e
a n g l e
( s e e
F I G . 1 1 ) o f 5 5 ° . The r i d g e d
r o l l e r
was p r o
vided
with a
shoulder
on each s i d e of t s
ridged
area t h e
s h o u l d e r s s t a n d i n g u s t s l i g h t l y
h i g h e r ' t h a n t h e r i d g e s t o
p r o v i d e a
s a f e g u a r d
a g a i n s t
a c c i d e n t a l damage t o t h e
r i d g e s a s a r e s u l t
of contact with
t h e backing r o l l e r .
A hot w e b
of polyp ropylene
6 . 5 i n c h e s wide and
0 . 0 0 3
inch
thick,
was extruded fro m a two-inch screw
e x t r u d e r
l o c a t e d
above t h e
p r o ? l i n g
u n i t , t h e h o t ,
ex
t r u d e d web
a l l i n g
v e r t i c a l l y down
i n t o t h e n i p between
t h e r i d g e d
r o l l e r
and
t h e
backing r o l l e r
a t
a
speed
of
30
f e e t
per
minute.
Cooling water
was
c i r c u l a t e d
through
t h e r i d g e d r o l l
t o
m a i n t a i n i t a t
15°C
d u r i n g
o p e r a t i o n ,
but the backing
r o l l e r was allowed
t o
run
a t a higher
t e m p e r a t u r e , namely 9 0 ° C .
The
c o n t a c t p r e s s u r e e x
e r t e d on
t h e
web‘as
i t
passed
between t h e r o l l e r
was
about
1 , 0 0 0
p s i ( a s
c a l c u l a t e d on t h e b a s i s of 80
p s i
a i r
p r e s s u r e i n
t h e j a c k i n g
c y l i n d e r s ,
each
o f which had a
3 - i n c h d i a m e t e r p i s t o n ) . The r e s u l t i n g p r o ? l e d web
l e a v i n g
the
r o l l e r s
was passed
t o
the ? r s t
G odet s e t
of
t h e
s t r e t c h i n g
u n i t . The
l a t t e r
was operated with a
s t r e t c h r a t i o
of 8 : 1
and a t an oven ( i . e . s t r e t c h i n g ) t e m
perature
of 145°C.
The
s t r e t c h e d w e b was
taken
o f f
a t
a speed of
24 0 f e e t
per minute. A omplete breakdown
into inidividual
? l a m e n t s
occurred
as
a
result
of
a
co n
t r o l l e d ? b r i l l a ti o n ‘ o f t h e w e b by t h e t i m e i t l e f t t h e s e c
ond
Godet s e t .
The
r e s u l t i n g yarn was then
r e e l e d - u p
i n the form of a 10,000
denier
tow. The average ‘ d e n i e r
o f ' t h e ' ? b e r s was
T h e ' f o l l o w i n ' g a d d i ti o n a l d a t a f u r t h e r de?ne t h e
oper
a t i o n ' j u s t ‘ d e ‘ s c r i b e d f
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