Note: Descriptions are shown in the official language in which they were submitted.
~WO 9511535~ . ~i 2 1 7 6 5 7 6 PCT/US9.1/136S7
FILMS PRODUCED BY BUBBLE FOR~IATION OF
- 5 COMPQSITIONS OF POLYAMIDE AND FUNCTIONALIZED
POLYOLEFIN
Ba~ J of the I~
0 Field of the Invention
The present invention relates to polyamide-r~ films
produced by bubble formation of c ~ o~;l;l lll~ which are useful, for
example, as carrier webs in the productiorl of c~ ""l,..~ materials.
D~d~. ;I.t of the Prior Art
A c~ r amount of progress has been made in the
1- ~6Y of ,~,hlrul.,~6- plastics Spurred mainly by the need of the
ll~t~ industry to produce li6hter weight, more ~;~ clIi~,;~,~
-~ ' s, much of the activity in this field has been devoted to
p~ plastics with enou6h strength a~d durability to replace many of
the metal structural support members of the -' '- body. The
l~,~u~ plastic part must exhibit similar structural strength and integnty
2s as the metal c~ while ! ' ~ reducing its wei6ht at equal,
or preferably, lower cost. As a result, a large amount of activity in
d~,~.' r ' 'g high strength structural Cu~ has been devoted to
utilizing sheet molding colll,uu~l-.d (SMC) and similar materials, which
allows relatively fast matched-die molding methods.
SMC is generally c~ mrnced of Cl~ ' ' ' 1e p~ - resin,
pa~ lr 1 ~ ~ polyester, styrene monomer (a cross-linl~ng
agent), pa~i ' filler, and chopped fiber ,~ r ~ t as well as
various other additives in minor amounts. This c . - material is
usually prepared by ~ the chopped fiber on a layer of fluid resin
35 supported on a moving polyamide film and then placing another layer of
polyamide film (onto which another layer of fluid resin may have been
deposited) on top to form a sandwiched ~.",~ which is passed
through a series of kneading and c.,..,l,~ ~;.", rolls and is usually wound
.. . _ _ _ _ , _ , .... ...... . . .....
WO 95/1535~ 7 6 5 7 6 PC~/US9~/136s7
into large rolls or festooned for storage. After a m~ n'r~n period of
about 2-5 days during which the material increases in viscosity to a
moldable ~ r~ the SMC is used to produce molded parts for
automobiles, boats, etc., by cutting a piece of d~ u~ size from the ' .
5 roll (or other structure), peeling away the polyamide carrier film(s), and
placing the SMC in a heated mold for ~;lllllll;~ lr!ou~ molding and complete
curing. Thus,SMCsandwichc~""l.r~ areusedirl Culll~ ivll
molding ~IVC~ s, and particularly in matched die molding operations.
A similar material, thick molding compound (TMC), is prepared by a
10 similar process and is used mostly in mjection moldirlg ~ l ;, ."c
Polyamide-con~ininE films are useful in the production of SMC
and TMC because polyamide is relatively iLU~J. ' '- to styrene
monomer and provides good strength. Commonly assigned U.S. Patent
4,444,829 teaches that films formed from blends of pol.~id~ and
5 various polyclefins are excellent carrier films fo} producing such
sandwich c-~",l,r~ That patent discloses the p~ '.u of such films
by a casting process. The prefe{red product described in the patent (a
blend of nylon 6 and ethylene vinyl acetate cu~oly...~,.) has been
~At~ r~ r used in the industry with much success. Such film possesses
20 excellent strength, ;",1, . ",. ~,ility to the styrene c . of the SMC,
and excellent peelability from the SMC material. Another cast film
product that has been used is formed from a blend of nylon 6,6 and a
modified polyll-ul),' ~
It is desirable to produce such film by a blown film process which
25 results in better roll COIlrul~l~. However, one problem facing the film
,.ud~ mdustry is the mability to blow extrude films wherein the
pol~ ' has a relatively low -' - ' weight (such as measured by a
formic acid viscosity of less than about 120 for nylon 6). As those skilled
in the art know, blown film e trusion involves forcmg a r~ film
30 a~mr~ n through an annular die head and forming a film bubble which
is ul~t~.}y collapsed and formed into a film. See, for example, Modern
Plastics Encyclopedia 1992, pages 245-248. It has been found that a
blend of ethylene-vinyl acehte copolymer and polyamide 6 having a
formic acid viscosity of less than about 120 could not be formed into a
35 film by the blown extrusion process as a shble bubble was not formed.
It would be desirable to provide a film produced by a blown film
process for use, for example, in the Ill~.I.Irh..lr ~: of SMC and other
~ ! . 2 1 7 6 5 7 6
C`J"~ msterlals, which utilized ~ow~r mole~ar weiBht P~IJ
and ye~ - I th~ excellent strength, s~ene ;~ and
poelability ~om the co.,.~ oc:~, Co~ of e~sting film.
~rv of the 1...
The presellt inve~tiOQ which ~sponds to the ~u~ b ~
problem fac ng the fi3m ~u~ v.. ind~y of the ina'oili~y to blow
10 extn~: fi3ms wherein the poly ' hss a selati~ely low nolec~al~
w~ight (for ~ylon 6, a formic acid visco3ity of 1~3s tnan abou~ 120),
provides ac.~ of pvl~ ~thaminimal amo~v~a
polyolefin naving ~eactive groups which raai~ltain the s~gth of the
b~bb duriug blo~ m ex~usion.
Thus, the present ~ve~tion prov~d~s a ~Im produced 'oy fc~lming a
bubble frûm a - . - cf~n~rnr-~ (a) ~ to aeeu~99.g welght
percent based on the,to~l ~ht of ~he . of a polyam~d$ and
(b) ~ least about O.l~w ~ght pcrc~t based on the tota~ we~ght of ttie
2a ~ JGn 1; ~ of a p~ ' '~ hav~g ~ nn~l groups whi~ r.dc~
w~th the fi.~i~ oups of ~c polyami~c wherein the fi~ o~l groups
of the poly~ ' '~ are pre5ent in an ~noun sufflclent to m3ii~ain the
~Loftheb~lc. ~ ta
The pr~s~t in~on also p~ovides a film ~oduced by folmmg a
~3ubblcfroma, ~ a) ~ul99.9weight ~7
pcrc~ bssc~ OD t~e total wdght of the - , of a ~1~ '
~at~,ul 0.~Iweig~t perce~t b. set on tbe tot. l weight of ~
of a pol~ ha~g fim~h~ol ~,u~ which are,feac~ve
~} with the r ' t ~ups of the pol~ l wherein tl~ oups
of the pol~ ~ r are p~e~e~ in an amount of at least ~Ol weight
p~ based o~ the to~} wei~t of ~e F~ c~lbl~ i~om about
0.01 to about lO wd~ht por~ent bascd on the total w~ght of sud
~ and ~c) abo~ 5 to about c,o wdgllt pef ~t based on the total
weightof~e~""~ of ~n, ~ t p
`J~5
Q~ sU~e ~. b~ ~sr~1 0~
AMEN~E~ SHEET
;C\. ~ F,~CHE~
2 1 76576
~ 4
The p~ese~t in~ oD ~iso i~ro~i~es a process of ~ming a
~de-c~ ;n~fi~mproduced ~abubble. The~
formiug the bubble fi-om a ~ c~ a)~ to
about 9~.g weight psrcent based OD the total weig~t of tile c~ .. of
5 a polyamide~; a~d (b) ~ about 0. I~w~ight percent based o~ the tota~ ~ le5s
weight of th~ c~ro~;~mt of a p~l~.Jl~fi~ having ~ t grol3pS w~ich
Ire reactive ~th thc fi~ctional ~oups of the p~ dc, where~n the
fitn~n~ gr~ups of thc poiyolefil~ are preseDLt in ~n Arnount suf~cient to
m~tnt~in the ~trength of the bubble.
10 1~ CC~C~ ~SLC~I 0
~t'J ~ 7 C~CU~ A ~
Detsiled D~_- of the P~ E
'O-
As discu~sed abovc, the fi~n of this ~ otl cc~ a
15 p~ ~ a~d a f--- - ' i polyolefin, ~ f~l~ also ~ an
~ - ' i polyolefill. Polyamides wcfill in the prcsent ir~en~on
are r~ct~7~ by the preSeDCe of rec~g c~l,u~c group~ as a~
Lnteg~al part of the polymer ch~in which arc ~d ~om one anothcr
by at least ~wo carbou atoms. Ill~ of thcse po ' arc thosc
2~ ha~ing rccu~ing units l~r~ y thc gene~al formula:
-~1HC(O)RC(O~ or~ R~(O)-
or a ~ thereof in which R and ~L are thc same or difl~er~t ant
2~i arc allylcne ~ou~ of a~ least about h~o c~o~ ~tnrn~ Cf;~libl~'allcylenc havi~ ~am about 2 to about 12 car~n atoms. Thc pol~
o~c pr~ i~o~ have rel~ively low ' ' wei~s. rhc
' - a~;dvi5co9ity ~FAV) of the pol~ is ~ from abo~t 50
to s~ 120 (ss mcssurcd by ASTM D-78g~. ID this mdho~, a
30 of I 1 ~ of p~ 100 ml of 90% folmic ac.id a~ 25~C is u~c~
of such p~l; ~ arc p~al~. ~ - - fa~mcd by thc
reac~o~ of ~liamines and diacids such ss poly(~ ir~ 3
~ylo~ 4,6), pol~ nc - lil ~ '-} ~nylon 6,~;
pO J ~ ~.IC ~--1 gtn j~ (~lOn 6 g~ y~
i~b ~ ylo~ 6~10), pol~ ~l ' ylcnc . ' ' ' ' - ~nylon 6,1);
;~c t,~ y~c~ 6,T); poly(h~
ylon ~,7), poly(~ La~ ~3 (~y}o~ g,8);
AMENO~D SHEET
21 76576
~wo 95/ls3s.l , PCI/US9-1113657
poly(n--nqmPthylene q.7Plqmi~) (nylon 9,9); poly(d~,a,~,;Ly-lene
q.7Plqmi~P) (nylon 10,9); and the like. Also llustrative of useful
polyamides are those formed by polymerization of amino acids and
derivatives thereof, as for example lactams. Illustrative of these usefu'
5 polyamides are poly(4-aminobutyric acid) (nylon 4); poly(6-
. J ~" ,~ .h~ ~ ~"~ic acid), also known a s poly(caprolactam) (nylon 6); poly(7-
.~";"~ ."-:c acid) (nylon 7); poly(8-aminooctanoic acid)(nylon 8);
poly(9-qmin~ acid) (nylon 9); poly(l0-qminn~Pcqn( ~ acid)
(nylon 10); poly(l l-qminnlmAp~q~nn:^ acid) (nylon 11); poly(l2-
10 qmin~ od~pc~qnclic acid) (nylon 12); and the like. Blends of two or morepolyamides may a'lso be employed.
Other polyamides tnat can be utilized are those resulting from
adipic acid and meta-xylylene diamines (nylon ~A); adipic aeid,
azelaic aeid and 2,2-bis-(p-amino-,y~ilvh~ Ayl)propane; t~ LIl.dlic aeid
5 and 4,4'-diamino-d;-,y~loh~,Ayl-.l. lLd~c; and the like.
Copolymer~, formed from reeurring units of the a~,ove - f,.~ ,cd
poly iPe may also be used. By way of illllctrqtir~n and not limi~qt~nn
sueh polyamide eopolymers inelude ~;a~lula~:l~ ' ylene
Iq~irqmi~1P eopolymer (nylon 6/6,6); ~ ' ylene
20 ~ lil ~P/eaprolaetam cul,ol.~.l,.,. (nylon 6,6/6); trimethylene
q.,~1 ;-";~lr eopolymer(nylontrimethyl
6,2/6,2); h~.A~..~ ..e s li, ' - ' 1- ' J' - ' i~P/
,d~-ul~.~,~ eopolymer (nylon 6,616,916); and the like.
Preferred pOl~aL...~c3 for use in the practice of this invention are
25 pOly(,a~lula~,~) (nylon6) andpoly(hs,Aa ,~ s ~i~ '-) (nylon
6,6), and blends and copolymers thereof. The most preferred pol~ '- is
poly(caprolactam).
~ ulyar li~s useful in the practice of this invention may be obtained
from ~ ~,;dl sources or prepared in accv.~cc with known
30 ,UI~IJarrl~ly ~ .
As " ,. ~1 ;""~Sd above, the polyar~udes of this inverltion have
relatively low l - ' weight. The FAV of the pol~ l~ s ranges from
about 20 to about 120, lu-~,r~ .dlJly from about 50 to about 120. Tbis
co..~ ùr~ds to a number average -' - ' weight of about 10,000 to
35 about 35,000. ~r~r~.dl)ly~ the mr l o ' weight ranges from about 20,000
to about 30,000.
W095/1535-1 2 1 7 ~ 5 76 PCTIUSg~/13657
The polyamide is present in an amount preferably of up to about
99.9 weight percent based on the total weight of the CuLu~;liul-, more
preferably about 50 to about 99.9 weight percent based on the total
weight of the comrocitlnn and most preferably about 75 to about 99.9
weight percent based on the total weight of the composition.
The polyolefins used herein include polymers of alpha-olefin
IllO~UIII~ l having between about 2 and about 6 carbon atoms and
includes homopolymers, copolymers (including graft copolymers), and
JUly~ of alpha-olefins. Illustrative homopolymer examples include
0 low, linear low, medium, or high density pul.r~,lLyl~,u~., polypropylene;
polybutylene; polybutene-l; poly-3- .~ 1; poly-pentene-l;
poly 1-~ t~ c-l; polyisobutylene; and polyhexene. Illustrative
CùpC~ and terpolymer examples include cop~ and terpolymers
of alpha-olefins with other olefins such as ethylene-propylene
copolymers; ethylene-butene copolymers; ethylene-pentene copolymers;
ethylene-hexene copolymers; and ethylene-propylene-diene copolymers
(EPDM). The term polyolefin as used herein also includes a~ le-
--styrene (ABS) polymers. Preferred pGI.~, r are those
prepared from alpha-olefins, most ~I~,f~,~al~l~ ethylene polymers,
copolymers, and terpolymers. The above p~ r - may be obtamed by
any known process. The p~ r may have a -'-- ' weight of
about 1,000 to about 1,000,000, and ~ about 10,000 to about
500,000. Preferred polyolefins are pol~ ,l.e, p~ uy~l~,l.c,
pGI~.~ ,llC, and copol~ll.el~, and blends thereof.
The polyolef~ns having fim~.rinn~1 groups useful herein are
p~ I r ~ which have fi~nrtinn~l groups which are reactive with the
fi~ groups of the pOIyalLlidC (which are a~ine amdlor ~,all,u~Lc
acid). Any r,. - ~ group which will react with the r~ groups of
the polyamide may be used in the present invention. Preferred filn~tinn~l
grûups are selected from the group co~ ûf I ~
pOl~,a bu.s~Lc acids and acid a.~ id~s thereof. The ~ "",t. i
polycarboxylic acids and anhydrides include maleic acid, maleic
;de, fumaric acid, fumaric anhydride, itacorlic acid, itaconic
~hy~hide, citracorlic acid, citraconic anhydride, and mixtures thereo
The more preferred fimrtinn~l group is anhydride and the most preferred
fimrtinn~l group is maleic anhydride.
~WO 95/lS35-1 ~ i ~ 2 1 7 6 5 7 6 PCTIUS9.1113657
The fimctinnAl group may be supplied by reacting the polyolefin
with the fimr.tinn~l group. The fimrtinnAI group may be grafted to the
polyo~efin by any known grafting process. Alternatively, the reactive
. ~ moiety may be copolymeri_ed into the backbone of the polyolefin. The
5 polyolefin may include one or more types of filnr,tinnAl groups.
. ' Commercially available polyolefins having fimrtinn~l groups which
are reactive with polyamide are preferably employed in the composition
of this invention. The polyolefin having filnr.tinnAl groups suitable fo} the
present invention may also be produced in accu-~ce with known
0 processes, including but not limited to the processes described in U.S.
Patents 3,481,910, 3,480,580; 4,612,155; and 4,751,270. In pPrfnrTnin~
the graft-poly", ;~A~ of IllI:~d~l ' I CdlbUA~LC acid and arlhydride to
the polyolefin, various methods have been utilized for initiating the
grafting polyTnP~i7Atinn process such as y-ray, X-ray, or high-speed
5 cathode ray ;" . l: -~ ;nl- processes, and a free radical initiator process. The
reaction of the pol.~ n with an I ' pOI~dll,uA~L., acid or an
anhydride in the presence of a firee radical (e.g., a peroxide) is the most
widely used method of the grafting process. The method of usmg
peroxide is alv ~ u~ since no special P~ ûr device is required
20 for initiating the graft p~l.~.. - ;~Al ;on reaction. Examples of the peroxides
, ~ include benzoyl peroxide, tert-butyl ~ u~b.,~ua~, cumene
h.~hu,u~.~u.~idc and a7o c~ u~ , such as azo-bis (is~u~luLutlilc).
U.S. Patent No. 4,612,155 discloses a grafting process . , ' ~ .g such a
radical initiator that obtains the grafting yield ûf 50-90% umder favûrable
25 ,u~ U.S. Patent No. 4,751,270 disclûses more ~
radical initiators that attain up to 100% graf~ng ~ and improve
~rafting ",~ir~ of the fimrhnnAl moiety to p~
Graft pol.~ AI ;nn reaction is generally ~- r~."- ~.i by standard
gra~L p~l.~.. ;,,~1;(~ t~Pr~ni~luPe known in the art, such as heating a
30 mixture of a polyolefin, a monomer of the fimr.hnn~l group, and a radical
initiator, after mixing those or in mixing ,u-u~,c.lmci, to a ~ ; at
which the pol~.,k,~L. becomes molten, under kneading of the mixture.
A;~,..a~ ly, the above-stated cu U,uuu~ are dissolved or s~ in
an à,U~lUIJlid~t~ solvent to perform the graft p~l~ reaction.
The polyolefin having fi~n~,tionAI groups is present in an amount
,UI-,C~.~d~ ' of at least about 0.1 weight percent based on the total weight
of the comrnC~tinn~ more preferably about 0.1 to about 10 weight perc~nt
.... ......... ....... ....... .... .. ...... ......... .. . . . . .. ..
WO 95/1535~ 2 ~ 7 ~ 5 7 ~ PCT/U59~1136~7
based on the total weight of the composition, and most preferably about
0.1 to about I weight percent based on the total weight of the
composition.
It has been ~uly~ ly found that the amoumt of fimrnonql groups
5 present based on the total weight of the composition required to maintain
the strengtb of the bubble formed during production of the blown film is "
minimal compared with the prior art teachings. (See for example U.S.
Patents 5,010,136; 5,047,479; 5,064,700; 5,122,570; and 5,126,407.)
The fim~ti~nql groups of the polyolefin are present m an amount suffi'cient
0 to mamtain the strength of the bubble formed during production of the
~lm. The r"....l;,,n~l groups of the polyolefi'n are present in an amount
preferably of about 0.01 to about 10 weight percent based on the total
weight of the polyolefim, more preferably about 0.1 to about 5 weight
percent based on the total weight of the polyoleil, and most ,ul~rl,ldbly
15 about 0.2 to about 1 weight percent based on the total weight of the
polyolefi'n.
Although not wishing to be bound by theory, it is believed that the
fimrti~nql groups of the polyolefin react with the fi~nrh~nql groups on the
polyamide. In other words, it is believed that the anhydride or acids
20 groups of the polyolefm react with the amine groups on the pol.~ ,.;c
chain ends of the polyamide. These reactions graft the pol~ to the
p~ It is believed that these reactions . ' to the bubble
strength.
Unlike "dll,uA.~ acids amd ~h~.hid.,~, esters on the pûl~
25 undergo minimal or no reaction with amine groups on the polymeric chain
ends of the polyamide. It is believed that this explains why a bubble did
not form when an attempt was made to blow eAtrude film fro~n a blend of
c;hjl"ll~ .~1 acetate copolymer and polyamide 6. Thus, it is believed
that cf~mro~ih~n~ such as the blends of: pol~ amd et~ylene-
30 methyl acrylate copolymer taught by U.S. Patent 3,472,916 andpoly 1~ amd ethylene-methyL,~,,yl~,-.u.,;ll~lylic acid taught by U.S.
Patent 4,174,358 would not form a bubble.
Pr-,r~ldl,l~, the present invention further c~ s r, ~ l;,- d
polyolefin. The ...,r,... 1;~ l;, d polyolefins include those mPnfi~nod
35 above which do not have the ~rulr~ n~d fimrhl)nqi groups attached
thereto. These include polymers of alpha-olefin, ..~ ...- .... r~ having
between about 2 and about 6 carbon atoms and includes homopolymers,
W095/1535~ 2 1 76576 PCTIUS9.1113657
copolymers (including graft copolyrners), and terpolymers of alpha-olefins
and unlike the above-described polyolefin having fi~nction~l groups, the
polyolefin does not have functional groups, i.e., is l."r"... 1;....,.1;,~.1
Illustrative homopolymer examples include low, linear low, medium, or
5 high density polyethylene; polypropylene; polybutylene; polybutene-l;
poly-3 -methylbutene- 1; poly-pentene- 1; poly-4-methylpentene- 1 ;
polyisobutylene; and polyhexene. Illustrative copolymer and terpolymer
examples include copolymers and terpolymers of alpha-olefins with other
oleftns such as ethylene-propylene copolymers; ethylene-butene
0 copolymers; ethylene-pentene copolymers; ethyl~,,c-h~,A~,~c copolymers;
and ethylene-propylene-diene copolymers (EPDM). The above
polyolefins may be obtained by any known process. The pcl~,L,liu
c~ may have a molecular wcight of about l,000 to about
1,000,000, and preferably about 10,000 to about 500,000. Preferred
5 polyolefins are polyethylene, pol~ u~yl~,l.e, polybutylene, and
C~lGI.~ -, andblendsthereof. The .r,...~ t;, dp~ provides
good release piv~ when the present film is used in the production of
sandwich c~ .o~:t- ~ of SMC, TMC or other ~ material, and are
generally less expensive than the r " 1 '~ polyolefins.
The Imfimrhnnsli7Pd polyolefin is present in an amolmt IJ.. f~
of about 5 to about 50 weight percent based on the total weight of the
c~....l.o~ - more preferably about 5 to about 40 weight percent based
on the total weight of the composition, and most ~ about 5 to
about 25 weight percent based on the total weight of the c-~
The film of the present invention may be prepared by ih~, uu~l~
blending together the polyatrlide, polyoleftn having fimrh~m~l groups, and
-nfi1nr.h~.n~li7Pd polyolefin if used, and optionally various minor amounts
of ~ --~y used additives such as pigi~nents, heat ' '
antistatic agents, and the like. Preferably, a pigment is used so that it can
easily be .1. t~ d that all of the release fi;lm has been removed firom
the c ""l,~;t, material. Such pigment may be present in any desired
amoumt, such as from about O.Ol to about 2 weight percent ofthe
n, more preferably from about O.l to about 1.5 weight percent.
As mPntionPd above, the film of this invention is formed by a
bubble formation process. In this process, the film forming apparatus may
be one which is referred to in the art as a "blown film" apparatus and
includes an almular die head for bubble blown film through which the
. . .
wo 95/1535~ ~ 2 1 7 6 ~ 7 6 PCTIUS9~/13657
rlqetiri7~d film composition is forced arld formed into a film "bubble",
which is ultimately collapsed and formed into a film.
The film of this invention may be of any thickness desired and
includes those which have thicknesses typically less than about 16 mils
5 (400 llm). Preferably, the film has a thickness of from about 0.2 mil (5 ~
m) to about 10 mils (250 ~Lm); more preferably the fdm has a thickness of
from about 0.4 mil (10 ~m) to about 5 mils (130 llm), and most preferably
the film has a thickness of from about 0.5 mil (12.5 llm) to about 2 mils
(50 ~Lm). While such thi~ L-n~ee.~e are preferred as providing a readily
0 flexible film, it is to be umderstood that other film 1l- ;l L "~ may be
produced to satisfy a particular need and yet fall within the present
invention's scope.
The fi~ms of this invention may UpliULldll~ be stretched or oriented
m any direction if so desired using methods known to those of skill in the
5 art. In such a stTetching operation, the film may be stretched in either the
direction ~ ,l with the direction of 11IU.~ of the blown film,
also referred to m the art as the "machine direction", or m a direction
which is perp~n~ to the machine direction, amd referred to m the art
as the "~ VC; ~e direction" where the resulting film is "uniaxially"
20 oriented, or in both the machine direction and the ~ direction,
where the resulting film is "l,;~dllly" orienbd. Such biaxially r~riPntqtion
may be !~;...--ll ...~O..c or seq~n~iql If the film is oriented after
",~....r~ ;, the film typically is drawn by passing it over a series of
-g and heating rolls. The heated film mûves a set of nip rolls
25 du..~l--,~ at a faster rate tham the film entering the nip roUs at an
upstrea~n lûcation. The change of rate is ~ for by stretching in
the film. Typical process and range of c~--.~-l:l;....~ for mr~nn ~;Dl1Y
oriented polyamide films are ~lieclos~rl for example, in U.S. Patent No.
4,362,385.
As noted above with respect to the use of pigment in the
f~rmlllqtion it is import. nt in SMC, TMC and other ~ ---r ~
I ,r~ processes that the carrier film should also exhibit a peel
adhesion or peelability such that the film peels offeasily from the
. - material prior to molding with very little, if any, of the film
adhered to the c~mI-olm~
Typical SMC and TMC compound fnrmlllqti-)ne are known in the
art. For example, see the aru. - . .- .l ;nn~d commonly assigned U.S. Patent
WO 95/1535-1 , . . 2 1 7 6 5 7 6 PCT/U59 1~1365~
' '~
11
4,444,829, the disclosure of which is expressly iucullJula~ed herein by
reference.
The films of this invention offer a range of release properties
suitable for use in Yarious release film aprlir~tinnc The films are
5 particularly applicable for the production of prepreg material forms and in
.' the production of SMC, TMC as well as bulk molding c~ o~ (BMC).
The films are also particularly al,pL~ al,lc as a ca~rier web for the
production of fiber ,~ ru~ d panels (FRP). In each of these processes, a
carrier film is used in the l"udu~ uu l"ucedu,ci.
0 The process for the production of SMC generally c~.. l,. ;~,~c casting
a layer of heat-curable ~ resm, in fluid form, onto a
c~.--l;..-~u~ly advàm~Lug film of the present invention; Lulludu~.L~
~hlrul~lLlg material onto the adva~..Lug fluid layer; c- ~ ; e another
layer of film (onto which there may have been deposited a layer of
Il.. nse11;.. ~resin)tothetopsurfaceofthe",;"ru,~,.,dfluidlayerthereby
forming a;,aL lw;~,hed c- ""l'~ , adv e the 1~.;ch_~ c-- - l-o~
through a series of kneading and c-~ e rolls; and winding or
f ~lu~ g the sa.l~lw;~Led CULUL~ha;I~ for 71"'111rP'ihn
The process for the ~IUdU~;I;U~ of TMC generally ~
20 LLu~ .~a~Lug I;~-,-,..~; -, -~ l~ h~rul-,Lug fiber, i.e. desired lengths of
chopped fiber, with resin paste; applying the LLUIJl. ,, I ~ l/l.
C~....I.hc;l ;1-1~ to a moving carrier release fikn of the present irlvention; then
applying a second release film of the present invention to sandwich the
, ^ then moving the ~aL~ C~,...l.h-:~ -- through a
25 cnn~r~rtil~n area, thereby c ~ e the , - to form a sheet,
generally much thicker then SMC; and then cutting the TMC sheet into
desired lengths for packing. A process ~ the l,lu-lu.;Luu of TMC
utilizing release films is ~licrlnse~ for example, in U.S. Patent 3,932,980.
- It can be seen that by this invention, it is possible to provide a
30 blown film from relatively lower mrl- ' weight phl~ ' Such film
retains the desirable physical properties 1 ~i....- ~ earlier, and is
palLi~ useful as carrier webs in the production of SMC, TMC and
sirnilar c-~ o~ ; materials.
The present mvention is more fully illllctr~t~d by the following non-
35 limiting F 1.
WO 95/1535-1 '; ` PCI/US9~1/136~7
2~ 76576
12
COMPARATIVE EXAMPLE I
A blend c~mrri~in~ 90% nylon 6 (71 FAV) and 10% ethylene vinyl
5 acetate copolymer was extruded on a single screw extruder with a
Maddox m xing head screw on a blown film extrusion hne. The barrel
and die ~ p~ . were between 450 to 500F (232-260C); the die
gap was between 0.020 and 0.040 inches. Film could not be ~ r,.lly
produced from this blend because a bubble could not be l.~l;.~.i;~ll. .
In addition, blends of nylon 6 (70 FAV) and 10 to 20 weight
percent of an -nmn iifiPd polyolefin (linear low density cul,ol~ , of
ethylene-butene described below) could not be used to produce film by
the blown film process, again because a bubble could not be ,l~ll.l;.~l,~.~i
5 Moreover, under the above S~nrii~innc~ a blend of nylon 6 (130 FAV) and
20 weight percent of the same polyolefin cop~ likewise could not be
used to produce film by this method because a bubble could not be
h ~.fi
EXA~LE I
A blend of 90 weight percent nylon 6 (85 FAV) from ,AIliP i~
Inc., 0.5 weight percent of the maleic anhydride modi_ed polyolefi
25 described below and 9.5 weight percent of the ~ polyolefin
described below was extruded under the c-~A~ of CO~ d~
Example l above. Good bubble stability was ~ ' -d-ft r bubbles at blow
up ratios from 1.6 to 2.3, with Im ll~;- L ~ i of 0.0005 to 0.002 inch.
~wo 95/1535~ ~ 2 1 7 ~ 5 7 6 Pcr~sg~/l3657
.. . ...
13
CQMPARATIVE EXAMPLE 2 AND
EXA~LES 2 AND 3
Comparative Example 2 was a film formed from a composition of
5 90 weight percent nylon 6 (135 FAV) and 10 weight percent of ethylene-
vinyl acetate copolymer. The film was formed by blown film extrusion. -
Example 2 was a composition of 94 weight percent nylon 6 (85
FAV), I weight percent of maleic anhydride modified linear low density
poly(ethylene-butene) copolymer (0.3 weight percent maleic anhydride,
0 density of 0.904, melt index of 3.0), and 5 weight percent llnme~lifiPd
linear low density poly(ethylene-butene) copolymer (density of 0.900,
melt index of 5.0). The film was formed by blown film extrusion as
above.
Example 3 was a c~amr ~itinn of 90 weight percent of the nylon 6
5 of Example 2, I weight percent of maleic ~hJ ~idc modified p~ly~
of Example 2, and 9 weight percent of the ~ polyolefin of
Example 2. The film was formed by blown film extrusion as above.
The films were tested and had the following ~"u~ i.,;,. In the
following Table, COF means c~ of friction. Where two values
20 are indicated, the _rst value is in the machine direction and the second
value is in the l.~ c direction:
PROPERTY COMPARATIVE EXAMPLE 2 EXAMPLE 3
EXA~LE 2
TensileModulus 78740;B0,840 101,300;113,300 105,950;102,315
(psi)
Tensile Strength 18,530; 11,880 15,715;13,730 14,765;12,920
(pSi)
Tensile Elongation 347; 353 350; 366 345; 372
(%)
El~nendorfTear 23;159 29; 62 28; 79
(,_ 1~ ~,. )
Graves Tear 404, 530 494; 546 474; 526
(grams/rnil)
Surface Ener~ 36 36 36
Gloss 41 53 38
Dart Drop 0.72 (0.20) 2.13 (1.08) 2.34 (0.75)
(foot-pound/mch)
(Standard
Deviation)
COF - Film 0 39 0.32 0.31
. .
WO 95~1535 ~ ~ 2 i 7 6 5 7 ~ PCINS94113657 ~
14
The release properties of the present filrn were ~ to be as
good as the release ,ulu,uellies of the C~ ;ve filrn. In addition, the
styrene imp~ bilily and strerlgth were also as good as the C~ U~aliVe
5 film.
