MELTBLOWN HYDROPHILIC WEB MADE FROM COPOLYMER OF AN AMINE-ENDED POLYETHYLENE OXIDE AND A POLYAMIDE

TOILE HYDROPHILE OBTENUE PAR FUSION ET SOUFFLAGE A PARTIR D'UN COPOLYMERE D'OXYDE DE POLYETHYLENE TERMINE PAR UN GROUPEMENT AMINE, ET D'UN POLYAMIDE

English Abstract

Abstract
A process is disclosed for preparing a nonwoven web
comprising melt-blowing a composition comprising a block
copolymer, the block copolymer comprising: (a) recurring
units formed from an amine-ended polyethylene oxide; and (b)
recurring units formed from a polyamide.

Claims

- 25 -

Claims:

1. A process for preparing a nonwoven web comprising
melt-blowing a composition comprising a block copolymer,
wherein the block copolymer comprises:
(a) recurring units formed from an amine-ended
polyethylene oxide; and
(b) recurring units formed from a polyamide.
2. The process according to claim 1, wherein the
amine-ended polyethylene oxide has the general formula
Image
wherein the sum of a plus c ranges from about 2 to about 20,
and b is from about 5 to about 500.
3. The process according to claim 1, wherein the
amine-ended polyethylene oxide has a molecular weight of from
about 600 to about 2000.
4. The process according to claim 1, wherein the
amine-ended polyethylene oxide has a molecular weight of from
about 700 to about 1000.
5. The process according to claim 1, wherein the
amine-ended polyethylene oxide has a molecular weight of from
about 800 to about 900.
6. The process according to claim 1, wherein the
block copolymer comprises from about 5% to about 30% by
weight of the recurring units formed from an amine-ended
polyethylene oxide based on the weight of the copolymer.
7. The process according to claim 6, wherein the
block copolymer comprises from about 10% to about 15% by
weight of the recurring units formed from an amine-ended
polyethylene oxide based on the weight of the copolymer.
8. The process according to claim 1, wherein the
block copolymer comprises from about 40% to about 95% by



- 26 -

weight of the recurring units formed from a polyamide based
on the weight of the copolymer.
9. The process according to claim 8, wherein the
block copolymer comprises from about 70% to about 95% by
weight of the recurring units formed from a polyamide based
on the weight of the copolymer.
10. The process according to claim 1, wherein the
polyamide is selected from the group consisting of nylon 4,6;
nylon 6,10; nylon 6; nylon 11; nylon 12; nylon 66; MXD-6;
PACM-9; PACM-10; an PACM-12.
11. The process according to claim 1, wherein the
polyamide is a nylon.
12. The process according to claim 11, wherein the
nylon is nylon 6.
13. The process according to claim 1, wherein
(a) the amine-ended polyethylene oxide has the
general formula
Image
wherein the sum of a plus c ranges from about 2 to about 20,
and b is from about 5 to about 500; and
(b) the polyamide is nylon 6.
14. The process according to claim 13, wherein the
composition comprises
(a) about 15% of the amine-ended polyethylene
oxide, the sum of a plus c ranges from about 2 to about 3,
and b is about 8 to 140; and
(b) about 85% of nylon 6.
15. The process according to claim 1, wherein the
melt-blowing melt temperature is more than 80°C above the
melting temperature of the composition.
16. The process according to claim 1, wherein the
composition is melt-blown at a temperature greater than about
285°C.



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17. The process according to claim 1, wherein the
composition is melt-blown at a temperature of from about 310°
to about 340°C.
18. The process according to claim 1, further
comprising incorporating into the composition, into the block
copolymer, or both, at least one additive agent selected from
the group consisting of delustrants, antioxidants,
plasticizers, and flame retardants.
19. The process of claim 17, wherein the additive is
a homopolymer or a second copolymer and is mixed with the
block copolymer to form a polyblend.
20. The process according to claim 1, wherein the
block copolymer has a number average molecular weight of from
about 5,000 to about 50,000.
21. The process of claim 1, wherein the block
copolymer has a relative viscosity at 10% w/v in 90% formic
acid of less than about 50.
22. The process according to claim 1, further
comprising preparing the composition before the melt-blowing
step.
23. A melt/blown nonwoven web comprising a
composition which comprises a block copolymer, the block
copolymer comprising:
(a) recurring units formed from an amine-ended
polyethylene oxide; and
(b) recurring units formed from a polyamide.
24. The melt-blown nonwoven web of claim 23, wherein
the amine-ended polyethylene oxide has the general formula
Image
wherein the sum of a plus c ranges from about 2 to about 20,
and b is from about 5 to about 500.


- 28 -

25. The melt-blown nonwoven web of claim 23, wherein
the amine-ended polyethylene oxide has a molecular weight of
from about 600 to about 2000.
26. The melt-blown nonwoven web of claim 23, wherein
the amine-ended polyethylene oxide has a molecular weight of
from about 700 to about 1000.
27. The melt-blown nonwoven web of claim 23, wherein
the amine-ended polyethylene oxide has a molecular weight of
from about 800 to about 900.
28. The melt-blown nonwoven web of claim 23, wherein
the block copolymer comprises from about 5% to about 30% by
weight of the recurring units formed from an amine-ended
polyethylene oxide based on the weight of the copolymer.
29. The melt-blown nonwoven web of claim 28, wherein
the block copolymer comprises from about 10% to about 15% by
weight of the recurring units formed from an amine-ended
polyethylene oxide based on the weight of the copolymer.
30. The melt-blown nonwoven web of claim 28, wherein
the block copolymer comprises from about 40% to about 95% by
weight of the recurring units formed from a polyamide based
on the weight of the copolymer.
31. The melt-blown nonwoven web of claim 28, wherein
the polyamide is selected from the group consisting of nylon
4,6; nylon 6,10; nylon 6; nylon 11; nylon 12; nylon 66;
MXD-6; PACM-9; PACM-10; and PACM-12.
32. The melt-blown nonwoven web of claim 23, wherein
the polyamide is a nylon.
33. The melt-blown nonwoven web of claim 32, wherein
the nylon is nylon 6.
34. The melt-blown nonwoven web of claim 23, wherein
(a) the amine-ended polyethylene oxide has the
general formula
Image


- 29 -

wherein the sum of a plus c varies from about 2 to about 20,
and b is from about 5 to about 500, and
(b) the polyamide is nylon 6.
35. The melt-blown nonwoven web of claim 23, wherein
(a) the composition further comprises at least
one additive agent selected from the group consisting of
delustrants, antioxidants, plasticizers, and flame
retardants;
(b) the block copolymer further comprises at
least one additive agent selected from the group consisting
of delustrants, antioxidants, plasticizers, and flame
retardants; or
(c) both of the conditions (a) and (b) exist.
36. The melt-blown nonwoven web of claim 23, wherein
the block copolymer has a number average molecular weight of
from about 5,000 to about 50,000.
37. The melt-blown nonwoven web of claim 23, wherein
the block copolymer has a relative viscosity at 10% w/v in
90% formic acid of less than about 50.
38. A hydrophilic wipe comprising the melt-blown
nonwoven web of claim 24.
39. An absorptive liner for a garment, dressing, or
personal care item, the liner comprising the melt-blown
nonwoven web of claim 24.
40. A filter comprising the melt-blown web of claim
24.
41. A battery separator comprising the melt-blown
nonwoven web of claim 24.

Description

;~5;~5~

Description
MELTBLOWN HYDROPHILIC WEB MADE FROM
COPOLYMER OF ~N AMINE-ENDED
POLYETHYLENE OXIDE AND A POLYAMIDE
Technical Field
The present invention relates to processes for
preparing nonwoven webs by mel~-blowing a composition,
particularly a composition comprising a block copolymer,
wherein the block copolymer comprises: (a) recurring units
formed from an amine-ended poly~thylene oxide; and (b)
recurring units formed from a polyamide. This invention also
relates to melt-blown nonwoven webs containing such a block
copolymer. Also within the scope of the invention are wipes
(preferably hydrophilic), absorptive liners tsuch as for a
garment, dressing, or personal care items), filters, and
battery separators that contain the melt-blown nonwoven web
of the present invention.
The technique of melt-blowing is known in the art and
involves extruding a molten polymeric material into fine
streams and attenuating the streams to fine fibers by flows
of high velocity heated air that also break the streams into
discontinuous fibers. The die melt temperature, i.e., the
temperature of the polymer melt at the die, is generally
about 80-100C above the melting temperature of the resin.
Typically, a composition is melt-blown at about 310-340C.
Melt-blowing is discussed in the patent literature, e.g.,
Buntin et al., U.S. PatPnt No. 3,978,185; Buntin, U.S. Patent
No. 3,972,759; and McAmish et al., U.S. Pa~ent No. 4,622,259.
These patent disclosures are hereby incorporated by
reference.
Some resins known to be capable of being melt-blown
are, for example, polypropylenes, polyethylenes, polyamides,
and polyesters. (See, for example, NcAmish e~ al., paragraph
bridging columns 10-11.)



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_ 2 -

For compositions containing block copolymers of an
amine-ended polyethylene oxide and a polyamide, it is known
to melt-spin thes~ compositions to produce fibers, yarns and
woven fabrics. For example, Lofquist et al., HYdrophilic
Nylon for ImProved APparel Comfort, 55 Textile Research
Journal, No. 6, 325 (June 1985) di~closes the melt-spinning
of a block copolymer of nylon 6 and polyethylene oxide
diamine to produce hydrophilic fibers, yarns and woven
fabrics. Melt-spinning involves pumping molten polymer at a
constant rate under high pressure through a spinneret. The
liquid polymer streams emerge downward from the face of the
spinneret, usually into air. They solidify and are brought
together to form threads, which are wound up on bobbins. The
temperatures involved in melt-spinning are generally lower
than in melt-blowing.
Those skilled in the art, who have been accustomed to
melt-spinning compositions containing block copolymers of an
amine-ended polyethylene oxide and a polyamide as illustrated
in Lofquist et al., have generally believed that these
compositions could not be melt-blown. It has been thought
that the pol~ether groupings of the amine-ended polyethylene
oxide are heat-sensitive to temperatures above 28~C and,
consequently, that the compo~itions containing the polyether
groupings would thermally degrad~ to an undesirable degree at
the 31~-340C temperature range typically used for ~elt-
blowing. For example, as seen in Figure 1, Hydrofil~
87-0063, a block copolymer believad to contain about 85%
nylon 6 and about 15% of an amine-ended polyethylene oxide by
weight based on the weight of the copolymer, starts to
thermally degrade at abou~ 303C, a temperature below the
310 340C temperature range typicaliy used for melt-blowing.
Applicants have surprisingly discovere~, however, that
compositions containing a block copolymer of a polyamide and
an amine-ended polyethylene oxid~ can in fact be melt-blown,
despite the presence of ~he polyether grouping. Moreover,

_ 3 _ 2~5~

the nonwoven webs produced according to the present invention
have excellent hydrophilic properties.
It is an object of the present invention to provide a
melt-blowing process ~or preparing nonwoven webs, preferably
hydrophilic nonwoven webs.
Another ob~ect of thi~ invention is to produce webs
which are instantly wettable by a drop of cold water, and
webs that retain this property even after repeated rinsings
with water.
A further object of this invention is to produce melt-
blown, nonwoven webs that are strong, abrasive, and abrasion
resistant.
Other objects will be apparent from the specification
and claims.
Disclosure of the Invention
The present inven~ion is directed to a process for
preparing a nonwoven web comprising melt-blowing a
composition comprising a block copolymer, wherein the block
copolymer comprises: (a) recurring units formed from an
amine-ended polyethylene oxide; and (b) recurring units
formed from a polyamide. The present invention is also
directed to nonwoven webs obtained by this process.
Brief DescriPtion of the Drawinq
Figure 1 shows th~ melt viscosity profile o~ a
composition comprising a block copolymer of about 85% nylon 6
and about 15% o~ an amine-ended polyethylene oxide by weight
based on the weight of the copolymer. Compositions of this
type are presently sold b~ Allied Corporation under the name
Hydrofil~.
The point scatter at about 303C and about 3~5C
indicates the occurrence of thermal degradation.
Best Mode _or Carrying Out the Invention
The present invention is directed to a process for
preparing a nonwoven, preferabl~ hydrophilic, web by melt-
blowing a composition comprising a block copolymer, the block



. ~

. . . .
,

_ 4 ~ 5~

copolymer comprising: (a) recurring units formed from an
amine~ended polyethylene oxide; and (b) recurring units
formed from a polyamide.
A block copolymer is a polymer containing relatively
long chains of the recurring units of a particular polymer
with the chains being separated by recurring units of a
polymer having a different chemical composition. In a
different type of block copolymer, the block copolymer
contains relatively long chains of the recurring units of a
particular polymer, and the chains are separated by a low
molecular weight coupling group. ~ach of the aforementioned
polymer chains can be a homopolymer or a random copolymer.
Within the scope of the present invention are block
copolymers of more than two dissimilar monomers.
The block copolymer of the invention preferably
contains polyether blocks which are randomly inserted into a
polyamide chain, e.g., -A-PE-A-A-A-PE-A-PE-A-A-, where A is a
recurring unit formed from a polyamide and PE is a recurring
unit formed from an amine-ended polyethylene oxide.
The relative proportion of the recurring units formed
from the amine-ended polyethylene oxide of the invention can
vary widely, limited only by the melting point of the
copolymer and the degree of hydrophilicity required.
Typically, the percentage by weight varies from about 5% to
about 30% based on the weight of the copolymer. It is
preferred, however, that the block copolymer comprise from
about 10% to about 15% by weight of the recurring units
formed ~rom the amine-end~d polyethylene oxide based on the
weight of the copolymer. Most preferably, about 15% o~ the
block copolymer is made up of the amine-ended polyethylene
oxide recurring units, based on the weight of the copolymer.
Pref2rably, the amine-ended polyethylene oxide has of
the general formula
IH3 IH3 IH3
__XNCHCH2 (OCHCH2)a (OCH2CH2~b----(OCH2CH)C___NH___




.

-- 5 --

where the sum of a plus c ranges from about 2 to about 20 and
b varies from about 5 to about 500. Preferably, the sum of a
plus c ran~es from about 2 to about 3, and b is from about 8
to about 140.
The molecular weight of the amine-ended polyethylene
oxide can vary widely. In a preferred embodiment, however,
the amine-ended polyethylene oxide has a molecular weight of
from about 600 to about 2000. More preferably, the amine-
ended polyethylene oxide has a molecular weight of from about
700 to about 1000. In a most preferred embodiment, the
amine-ended polyethylene oxide has a molecular weight of from
about 800 to about 900.
The amine-ended polyethylene oxide useful in this
invention can be prepared by any process known to those
skilled in the art. Yeakey, U.S. Patent No. 3,654,370,
teaches a preerred process for preparing the amine-ended
polyethylene oxide, the disclosure of which is hereby
incorporated by reference. Yeakey discloses treating
polyethylene glycol with a minimum amount of propylene oxide
to generate a polyether with terminal secondary hydroxyl
groups. These hydroxyl groups are then converted to amines,
creating a polyethylene glycol with amine ends. The pro~ess
of Yeakey is conducted in the presence of ammonia and
hydrogen at a temperature of 150-275C and at a pressure of
about 500 to 5000 p.s.i.g. over a catalyst prepared by ~he
reduction of the oxides of nickel, copper and chromium.
The relative proportion of the recurring units formed
from the polyamide of the invention can vary widely.
~ypically, the percentage by weight of the recurring units
formed from the polyamide varies from about 40% to about 95%
based on the weight of the block copolymer. It is preferred,
however, that the block copolymer from about 70% to about 95
by weight o~ the recurring units formed from the polyamide.
More preferred i~ a copolymer comprising from about 80 to
about 90% by weight of the recurring units formed from the




j



polyamide based on the weight of the copolymer. Most
preferably, the block copolymer contains about 85% of the
polyamide recurring units.
Not all polyamides are nylons, and not all nylons are
polyamides. For example, some nylons such as nylon 4 or
those with a high content of relatively inflexible rings are
too unstable or have too high a melt viscosity to be melt
processible and, therefo~e, are not normally included in the
polyamide category. Moreove~, a class of polyamides distinct
from the nylons is prepared by the polymerization or
dimerization of vegetable oil acids and polyalkylene
polyamines, such as ethylenediamine or diethylenetriamine.
However, the term polyamide, as used throughout the
specification and claims, is hereby defined to include all
nylons.
A large number of polyamides is useful in the present
invention. Table I sets forth potentially useful polyamides
as follows:
Table I

Melting
Nylon Code Name Point, C
-
Aliphatic amino ~cid polyamid ~
22 poly(22-aminodocosanoic acid) 145
3 poly(3-aminopropionic acid) 330
2,2DM3 poly(2,2-dimethyl-3-aminopropionic
acid) 270
NM3 poly(N-methyl-3-aminopropionic acid) 225
NP3 poly(N-phenyl-3-aminopropionic acid) 205
AP poly(aminopivalic acid) 270
7S poly(7-aminothioenanthic acid) 235
Alipl~atic di min~diacid polyamides
10,1 poly(decamethylene carbonamide) 200
~0,2 poly(decamethylene oxamide) 290
12,6 poly(dodecamethyle~e adipamide) 210
12,10 poly(dodecamethylene sebacamide) 173
2,6 poly(ethylene adipamide) 310
.




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2,1 poly(ethylene carbonamide) 400
2,12 poly(ethylene dodecanediamide) 261
2,10 poly(ethylene sebacamide) 280
6,1 poly(hexamethylene carbonamide) 300
6,12 poly(hexamethylene dodecanediamide) 217
6,20 poly(hexamethylene eicosanediamide) 189
6,5 poly(hexamethylene glutaramide) 241
6,3M6 poly(hexamethylene 3-methyladipamide) 230
6,2 poly(hexamethylene oxamide) 320
8,12 poly(octamethylene dodecanediamide) 202
8,20 poly(octamethylene eicosanediamide) 179
5,3 poly(pentamethylene malonamide) 191
6,14 poly(hexamethylene tetradecanediamide) 209
4,1 poly(tetramethylene carbonamide) 400
4,12 poly(tetramethylene dodecanediamide) 245
6,S025 poly(hexamethylene sulfonyldivaleramide 215
6,4D03 poly[hexamethylene tetramethylenedi~ 410
(oxypropionamide)]
6,4DS026 poly[hexamethylene tetramethylenedi 241
(sulfonylcaproamide)]
6,S4 polythexamethylene thiodibutyramide) 200
6,S3 poly(hexamethylene thiodipropionamide) 219
2,S5 poly(ethylene thiodivaleramide) 220
2,S7 polytethylene thiodienanthamide) 210
6,10DSO26 poly(hexamethylene decamethylenedi- 210
tsulfonylcaproamide)
Aromatic-al iphatic polyamides
4,4'DP,6 polyt4,4'-diphenylene adipamide) 400
4,4~DP,10 poly(4,4'-diphenylene sebaoamide) 435
lO,I poly(decamethylene isophthalamide) 186
lO,pP2 poly(decamethylene p-phenylene- 242
diacetamide)
poly[decamethylene p-phenylene- 188
di(oxyacetamide)]
poly(decamethylene p- 265
phenylenedipropionamide)
lO,T poly(decamethylene terephthalamide) 276
poly(2,2-dimethyltrimethylene 284
4,4'-sulfonyldibenzamide~
poly(4,4~-ethylenediphenylene 400
adipamide)
poly(4,4'-ethylenediphenylene 360
sebacamide)
2,T poly(ethylene terephthalamide) 455
2,P poly(ethylene ph~halamide) 250
7,pP2 poly(heptamethylene p-phenylene- 234
diacetamide)
6,5tBI poly(hexamethylene 5-tert- 210
butylisophthalamide)




.

- 8 ~

6,4,4'DBZ poly(hexamethylene 4,4'-dibenzoamide) 360
poly(hexamethylene 2,5- 143
dimethylterephthalamide)
poly(hexamethylene 4,4'- 175
ethylidenedibenzoamide)
poly(hexamethylene 4,4'- 180
isopropylidenedibenzoamide)
6,MT poly(hexamethylene 248
methylterephthalamide)
6,mæ2 poly(hexamethylene m- 182
phenylenediacetamide)
6,pP3 poly(hexamethylene p- 295
phenylenedipropionamide)
7,T poly(heptamethylene terephthalamide) 341
6,T poly(hexamethylene terephthalamide) 371
6,NMT poly(hexamethylene N- 260
methylterephthalamide)
4,4'MDP,6 poly(4,4~-methylenediphenylene 356
adipamide)
poly(3,3'-dimethyl-4,4'-methylene- 326
diphenylene adipamide)
poly(4,4'-methylenediphenylene 275
azelamide)
poly(4,4'-methylenediphenylene 280
sebacamide)
poly(3,3'-dimethyl-4,4~-methylene- 227
diphenylene sebacamide)
4,T poly(tetramethylene terephthalamide) 436
3,T poly(trimethylene terephthalamide) 399
3MnP,6 poly(3-methyl-m-phenylene adipamide) 225
3MmP,10 poly(3-methyl-m-phenylene sebacamide) 200
8,T poly(octamethylene terephthalamide) 315
mP,6 poly(m-phenylene adipamide) 296
oP,6 poly(o-phenylene adipamide) 179
pP,6 poly(p-phenylene adipamide) 262
pPDE,6 poly(p-phenylenediethylene adipamide) 310
pPDE,9 poly(p-phenylenediethylene azelamide) 250
pPDE,10 poly(p-phenylenediethylene sebacamide) 285
mP,10 poly(p-phenylene sebacamide) 256
5,T poly(pentamethylene terephthalamide) 353
pX,22 poly(p-xylylene decosanediamide) 240
pX,12 poly(p-xylylene dodecanediamide) 272
pX,S poly(p-xylylene glutaramide) 280
pX,6 poly(p xylylene adipamide) 340
mX,9 poly(m-xylylene azelamide) 172
pX,18 poly(p-xyIylene octadecanediamide) 235
mX,7 poly(m-xylylene pimelamide) 192
pX,7 poly(p-xylylene pimelamide) 284
m~,10 poly(m-xylylene sebacamide) 193
mX,8 poly(m-xylylene suberamide) 213
pX,8 poly(p-xylylene suberamide) 305
pX,4 poly(p-xylylene succinamide) 360
mX,14 poly(m-xylylene tetradecanediamide) 192



Aromatic-aromatic polyamides
4,4'DP,T poly(4,4'-dlphenylene terephthalamide) 500
polyt3,3'-dimethyl-4,4'-diphenylene 440
terephthalamide)
poly(3,3'-dimethyl-4,4'-diphenylene 254
N, N' -diethylterephthalamide)
poly(4,4'-diphenylene N,N'- 316
diethylterephthalamide)
poly[decamethy~ene 4,4~-ethylenedi- 220
(phenyleneoxyacetamide)]
poly(4,4'-dimethylheptamethylene 4,4'- 268
sulfonyldibenzamide)
2,4,4'S02DBZ poly(ethylene 4,4~-sulfonyldibenzamide) 380
2,T poly(ethylene terephthalamide) 455
poly(ethylene N, N' -dibutylterephthal- 190
amide)
poly(ethylene ~,N'-diethylterephthal- 230
amide)
poly(ethylene N, N' -dimethylterephthal- 379
amide)
poly(hexamethylene 2,5-dihydroxy- 334
terephthalamide)
6,pPD02 poly[hexamethylene p-phenylenedi- 237
(oxyacetamide)]
6,4,4'S02DBZ poly(hexamethylene 4,4'-sulfonyl- 310
dibenzamide)
4,4'MDP,T poly(4,4'-methylenediphenylene 420
terephthalamide)
poly(4,4'-methylenediphenylene 195
N, N' -dibutylterephthalamide)
poly(3,3'-dimethyl-4,4'-methylene- 380
diphenylene terephthalamide)
poly(3,3~-dimethyl-4,4~-me~hylene- 229
diphenylene N, N~ -dimethyl-
terephthalamide)
poly(4,4~-methylenediphenylene 264
N, N~ -dimethylterephthalamide~
pPDE,mæ2 poly(p-phenylenediethylene 222
m-phenylenediacetamide)
6,ST poly(hexamethylene dithio- 190
terephthalamide)
poly~hexamethylene 4,4'-oxydi- 220
(phenyleneoxyacetamide)]
mX,I poly(m-xylylene isophth~lamide) 225
pX,I poly(p-xylylene isophthalamide~ 279
pX,P poly(p-xylylene phthalamide) 230
mX,T poly(m-xylylene terephthalamide) 300
pX,T poly(p-xylylene terephthalamide) 350
4,4'DP,I polyt4,4'-diphenylene i~ophthalamide) 400
poly(3,3'-dimethyl-4,4'-diphenylene 365
isophthalamide)




':


.

- 10 ~ ?~

4,4'MDP,I poly(4,4'-methylenediphenylene 400 isophthalamide)
4,S02DBZ poly(tetramethylene 4,4'-sulfonyl- 358
dibenzamide)
3,S02DBZ poly(trimethylene 4,4'-sulfonyl- 298
dibenzamide)
3,T poly(trimethylene terephthalamide) 399
poly(trimethylene N, N' -dimethyl- 220
terephthalamide)
mP,I poly(m-phenylene isophthalamide) 365
Alicyclic-aliphatic and
heterocycl ic-al iphatic polyamides
1,3CH,6 poly(l,3-cyclohexylene adipamide) 300
(trans)
1,4CH,6 poly(l,4-cyclohexylene adipamide) 400
1,3CH,9 poly(l,3-cyclohexylene azelamlde) 300
(trans)
CH~M,12 poly(l,4-cyclohexylenedimethylene 278
dodecanediamide)
CHDM,10 poly(l,4-cyclohexylenedimethylene 300
sebacamide)
CHDM,7 poly(l,4-cyclohexylenedimethylene 293
pimelamide)
CHDM,5 poly(l,4-cyclohexylenedimethylene 290
glutaramide)
1,3CH,10 poly(l,3-cyclohexylene sebacamide) 290
(trans)
CPDM,10 poly(l,2-cyclopropylene- 223
dimethylene sebacamide)
CP,10 poly(cyclopropylene sebacamide) 220
lO,THF3 poly(decamethylene tetrahydrofuran- 178
2~5-dipropionamide)
2,CPl poly(ethylene cyclopropane- 350
dicarboxamide) ( trans)
2,THF3 poly(ethylene tetrahydrofuran- 218
2,5-dipropionamide)
7,THF3 poly(heptame~hylene tetrahydrofuran- 148
2,5-dipropionamide)
6,1,2C2 poly(hexamethylene cyclohexane- 255
1,2-diacetamide)
6,1,2Cl poly(hexamethylene cyclohexane- 242
1,2-dicarboxamide) (trans)
6,1,3Cl poly(hexamethylene cyclohexane- 312
1,3-dicarboxamide) ( trans )
6,1,4Cl poly(hexamethylene cyclohexane- 360
1,4-dicarboxamicle) ( trans )
6,CPl poly(hexamethylene cyclo- 300
propanedicarboxAmide) (trans)
6,2,5F3 poly(hexamethylene furan-2,5- l90
dipropionamide)



6,3MCP poly(hexamethylene 3-methylcyclo- 270
propanedicarboxamide) (trans)
poly(hexamethylene 1-methylpyrrole- 180
2,5-dipropionamide)
poly(hexamethylene 1-methylpyrroli- 200
dine-2,5-dipropionamide)
poly(hexamethylene piperazine- 168
1,4-diacetamide)
6,THF3 poly(hexame~hylene tetrahydrofuran- 182
2,5-dipropionamide)
8,THF3 poly(octamethylene tetrahydrofuran- 180
2,5-dipropionamide)
5,THF3 poly(pentamethylene tetrahydrofuran- 153
2 t 5-dipropionamide)
poly[l,4-cyclohexylenedi- 384
(oxytrimethylene)terephthalamide]
poly~l,4-cyclohexylenedi- 224
(oxytrimethylene) 4,4'-
tetramethylenedi(oxybenzoamide)
Pip,CPl poly(piperazine cyclopropane- 330
dicarboxamide) ( trans)
Pip,10 poly(piperazine sebacamide) 180
Pip,8 poly(piperazine suberamide) 300
4,THF3 poly(tetramethylene tetrahydrofuran- 210
2,5-dipropionamide)
Alicyclic and Neterc~ lic Pol~amides
poly[1,4-cyclohexylenedi- 196
(oxytrimethylene)adipamide]
poly[l,4-cyclohexylenedi- 250
(oxytrimethylene) 4,4'-
ethylenedi(oxybenzoamide)]
poly[l,4-cyclohexylenedi- 215
(oxytrimethylene) 4,4'-
hexamethylenedi(oxybenzoamide)]
poly[l,4-cyclohexylenedi(oxy- 246
trimethylene) oxamide]
Aro~atic and aliphatic amino ac:id polyamides
2P5 poly(p-aminoethylphenylvaleric acid? 275
poly(aminotoluic acid) 300
poly(p-amino-~-methylhydrocinnamic 250
acid)
P2 poly(aminophenylacetic acid~ 410
P3 poly(p-aminophenylpropionic acid) 310
poly(p-aminomethylhydrocinnamic acid) 300
IP2 poly(p-aminomethylphenylacetic acid) 355
IP3 poly(p-aminomethylphenylpropionic acid) 300
IP4 poly(p-aminomethylphenylbutyric acid) 267
IP5 poly~p-aminomethylphenylvaleric acid) 233




~ :~

:

- 12 ~

2P2 poly(p-aminoethylphenylacetic acid) 283
2P3 poly(p-aminoethylphenylpropionic acid) 382
2P4 poly(p-aminoethylphenylbutyric acid) 224
Alicyclic-aromatic and heterocyclic-
aromatic polyamides
poly(1,4-cyclohexylene 3,3'- 390
dibenzoamide)
poly(1,4-cyclohexylenedimethylene 310
isophthalamide) ( trans )
poly(1~4-cyclohexylene 3,3'- 174
methylenedibenzoamide)
poly(1,2-dimethylenecyclopropylene 220
isophthalamide
poly(cyclopropylene isophthalamide) 250
poly(4,4'-diphenylene pyridine- 365
2,6-dicarboxamide)
poly(3,3'-dimethyl pyridine- 376
2,6-dicarboxamide)
DMT,6 poly(2,5-dimethylenethiophene 253
adipamide)
poly(2-methylpiperazine phthaiamide) 350
2MPip,T poly(2-methylpiperazine 350
terephthalamide)
Pip,P poly(piperazine phthalamide) 325
DMT,10 poly(2,5-dimethylenethiophhene 210
sebacamide)
DMT,7 poly(2,5-dimethylenethiophene 212
pimelamide)
DMT,9 poly(2,5-dimethylenethiophene 197
azelamide)
~Ieterocycl ic diamine-diacid polyamides
CP,CPl poly(cyclopropane cyclopropane- 285
dicarboxamide)
1,2DMCP,CPl poly(l,2-dimethylenecyclopropane 220
cyclopropanedicarboxamidq)
Pip,3MCP1 poly(piperazine 3-methylcyclo- 280
propanedicarboxamide (trans)
_

- 13 - %

Prefexred polyamides are nylone 4,6
[poly(tetrame~hylene adipamide)]; nylon 66
[poly(hexamethylene adipamide)]; nylon 6,10
[poly(hexamethylene sebacamide)]; nylon 6
[poly(pentamethylene carbonamide)]; nylon 11
[poly(decamethylene carbonamide)]; nylon 12
[poly(undecamethylene carbonamide)]; MXD-6 [poly(meta-xylene
adipamide)]; PACM-9 [bis(para-aminocyclohexyl)methane
azelamide]; PACM-10 ~bis(para-aminocyclohexyl)methane
sabacamide]; and PACM-12 [bis(para-aminocyclohexyl)methane
dodecanoamide]. More preferably the polyamide is a nylon,
with nylon 6 being the most preferred nylon.
Polyamides are condensation products that contain
recurring amide groups as integral parts of the main polymer
chains. Linear polyamides can be formed by the condensa~ion
of bifunctional monomers. If the monomers are amino acids,
e.g., 6-aminohexanoic acid, the polymers are called AB types
(A representing amine groups and B representing carboxyl
groups). If the polymers are formed from the condensation of
diamines and dibasic acids, they are called AABB types.
Although polyamides generally are considered to be
condensation pol~mers, they can also be formed by addition or
ring-opening polymerization. q'he ring-opening pol~merization
method of preparation is especially important for some AB
type polymers made from cyclic lactams as recurring units,
e.g., epsilon-caprolactam, hexahydro-2H-azepin-2-one or 2-
pyrrolidinone gamma-aminobutyrolactam.
Methods for preparing polyamides are well known and
described in various publications. For example, Billmeyer/
Textbook Polymer Science 409 (3d ed. 1984), discloses the of
preparation of nylon 6 and nylon 66, the disclosure of which
i~ incorporated by reference. q'o prepare nylon 6, Billmeyer
teaches the polymerization of caprolactam by adding water to
open the rings and then removing the water again at elevated
temperature, during which a linear polymer forms. To prepare

- 14 ~

nylon 66, Billmeyer teaches the polymerization of adipic acid
and hexamethylenediamine.
The preparation of polyamides can be batchwise or a
continuous process. An autoclave or a continuous reactor can
be used.
The composition may consist of up to about 100% by
weight of the block copolymer, based on the weight of the
extruded resins. In a preferred embodiment, the composition
comprises a block copolymer comprising
(a) the amine-ended polyethylene oxide having
the general formula
IH3 IH3 FH3
_-xNcHcH2 (OCHCH2)a (CH2CH2)b--(0CH2CH)c------NX_----
wherein the sum of a plus c ranges ~rom about 2 to about 3,
and b is from about 8 to about 140; and
(b) the polyamide, nylon 6.
Even more preferably, the composition comprises a block
copol~mer comprising about 85% nylon 6 and about 15% of an
amine-ended polyethylene oxide by weight based on the weight
of the block copolymer. Compositions of this type are
commercially a~ailable ~rom the Allied Corporation under the
name Hydro~
In another preferred embodiment, the block copolymer
useful in the present invention has a number average
molecular weight of from about 5,000 to about S0,000. It is
also preferred that the block copolymer has a relative
viscosity when measured at 10~ w/v concentration in 90~
formic acid of less than ~0, more preferably between about 34
to about 39.
The composition, the copolymer, or bo~h may also
contain one or more additive agents. In a pre~erred
embodiment, the additive is a homopolymer or a second
copolymer and is mixed with the bloc~ copolymer to form a
polyblend. The ~ollowing are representa~ive additive agents:

- 15 -

(a) delustrants such as barium sulfate, clays, and chalk;
(b) antioxidants such as phenols, aromatic amines, and salts
and condensation products of amines and aminophenols with
aldehydes, ketones, and thio compounds; (c) plasticizers such
as phthalate esters, phosphate esters, adipates, azelates,
oleates, sebacates, epoxy plasticizers, fatty acid esters,
glycol derivatives, sulfonamides, and hydrocarbons and
hydrocarbon derivatives; and (d) flame retardants such as
halogenated aliphatics, antimony oxide (either alone or in
combination with a halogen), brominated aromatics, and
organophosphorus compounds. Speci~ic examples of the above
additive agents and other additive agents are found in Modern
Plastics Encyclopedia 1984-85, the disclosure of which is
incorporated by reference.
A preferred antioxidant is a phenolic antioxidant from
Ciba Geigy, Irganox 1010. When the additive agent is an
antioxidant, the copolymer preferably contains from about
0.1% to about 0.5% by weight of the antioxidant based on the
weight of the block copolymer. More preferably, however, the
block copolymer contains about 0.5% by weight of the
antioxidant based on the weight of the block copolymer.
Tables II and III illustrate the physical properties of
preferred block copolymers of nylon 6 and an amine-ended
polyethylene oxide ("APEO"), as follows:

- 16 ~ 5

Table II. Physical Properties of Nylon 6 Containing
Different Molecular Weight AP~O~s (Sold
Under the Name of Jeffamine~
APEO Relative viscosity Tma~ Tua/
Concentrationin formic acid C dC

Control (all nylon 6 50 225 42
containing 0% APEO)
15% APEO; Molecular
weight 2001 35 223 6
15% APEO; Molecular
weight 900 38 217 19
15% APEO; Molecular
weight 600 38 214 26

a Crystalline melting point and glass transition temperature
as determined by differential scanning calorimetry.

Table III. Polymer Properties of Nylon 6JAPEO Block
Copolymers.

Copolymer Number Glassa Melt
composition average Meltinga transition viscosity,b
% APEO molecular point temperature Pa.s, 260C
weight C C 2000 s-
(MW=2001)

0 20lO00 224 42 120
22,000 224 22 120
19,000 22~ 10 100
lS 20,000 223 6 85
28,000 223 0 125
-

a Crystalline melting point and glass transition
temperature as determined by differential scanning
calorimetry.




`

- 17 -

b Melt viscosity as determined on a capillary melt
rheometer using a 33 to 1 orifice.
In one particular embodiment of the present invention,
the composition containing the block copolymer is itself
prepared before the melt-blowing step. Methods for preparing
the block copolymer of this invention are well known to ~hose
skilled in the art. Block copolymer preparations have been
described in the patent literature using at least two
techniques. One technique is melt blending two homopolymers.
The melt blending of two homopolymers using elevated
temperatures typically results in the formation of an
intimately mixed physical mixturs with an insignificant
amount cf chemical bonding between the polymer chains. When
the conditions are closely controlled, however, block
copolymers with long sequence lengths can occur due to a
small amount of amide interchange accompanied by an
insignificant number of random sequences. Such a technique
is disclosed in Zimmerman, U.S. Patent No. 3,393,252.
Another method of preparing block copolymers has been
described in Honda et al., U.S. Patent No. 3,683,047. This
method consists of melt blending two homoprepolymers of
molecular weight from 1000 to 4000, one prepolymer being
carboxyl terminated and the other prepolymer being amine
terminated. The result of the polymerization is a block
copolymer having very little randomization, as indicated by
the reduced decrease in melting point during the blend time.
According to the present invention, the composition is
melt-blown to produce a nonwoven web. Melt-blowing involves
extruding a molten polymeric material into fine streams and
attenuating the streams to fine fibers by flows of high
velocity heated air that also break the streams into
discontinuous fibers.
The die melt temperature, i.e., the temperature of the
polymer melt at the die, is generally about 80-100C above
the mel~in~ temperature of the resin. Preferably, however,

-
- 18 ~ 5~,~

the die melt temperature can be more than about 100C above
the melting temperature of the composition. In an especially
preferred embodiment, the present composition is melt-blown
at a temperature greater than about 285C. In a still more
preferred embodiment, the composition is melt-blown at a
temperature of from about 310 to about 340C.
The technique of melt-blowing is known in the art and
is discussed in various patents, e.g., Buntin et al., U.S.
Patent No 3,978,185; Buntin, U.S. Patent No. 3,972,759; and
McAmish et al~, U.S. Patent No. 4,622,259, the disclosures of
which are hereby incorporated by reference. Although one ox
more of these paten~s, e.g., Buntin, U.S. Patent No.
3,972,759, states that a polymer degradation step is required
before melt-blowing to ensure that the polymer resin has the
requisite viscosity, a polymer degradation step is optional
in the present invention. This is because the present
composition containing the block copolymer preferably has the
requisite viscosity set forth in Buntin, U.S. Patent No.
3,972,759 for the production of high quality nonwoven webs
without a polymer degradation step. Specifically, the block
copolymer of the invention preferably has an app~rent
viscosity of from about 50 to about 500 poise, measured at a
shear rate of from about 700 to about 3500 sec l and a
temperature of from about 250 to about 300C.
In accordance with this invention, commercially useful
resin throughput rates can be utilized. Suitable resin
throughput (flow) rates range ~rom nominally about 0.1 (e.g.,
as low as about 0.07) to about 5 grams per minute per nozzle
orifice.
In the melt~blowing process of the present invention,
the composition is attenuated while still molten to fibers
having diameters of 0.5 to ~00 microns. The diameter of the
attenuated fibers generally decreases as the gas flow rate
increases through the gas outlets or slots on either side of
the nozzle die opening~. Typically, gas flow rates may vary




~,

19

from 2.5 to 100 pounds per minute per square inch of gas
outlet area, but may be even greater. At low to moderate gas
rates of from about 2.5 to about 20 pounds per minute per
square inch of gas outlet area, and for resin flow rates of
from about 0.1 to about 5 grams per minute per orifice, the
fibers can be 75 cm or longer between fiber breaks. Fibers
produced in this low to moderate gas flow rate range
typically have diameters of from about 8 to about 200-400
microns, preferably from about 8 to about 50 microns.
As gas rates increase for a selected resin flow rata of
the composition, the number of fiber breaks increase,
eventually producing coarse "shot." "Shot" consists of large
globs of polymer having a diameter at least several times
that of the average diameter size of the fibers and at least
0.3 millimeter in diameter. The production of coarse shot is
objectionable when a uniform mat is desired. Further, if a
mat is calendered or further treated, the coarse shot will
produce imperfections or even holes in the surface of the
mat.
At high gas rates of from more than about 20 to about
100 pounds per minute per square inch of gas outlet area,
polymer fibers are produced which typically exhibit fine shot
less than about 0.3 millimeter, pre~erably less than about
~.1 millimeter in diameter. At the high air rates for resin
flow rates in the range ~rom about 0.1 to about 5 grams per
minute per orifice, the fiber diameter is ~enerally between
about 0.5 and 5 microns.
Subsequent collection of the fibers on a screen, belt,
drum, or the like yields a mat of the fibers. Melt-blown
webs according to the present invention can be point-bonded
for added mechanical strength, or they can be laminated with
other webs to obtain structures with multiple functions.
For ~xample, the nonwoven webs o the present invention
can be bond~d by a point application of heat and pressure
using patterned bonding rollers. At these points where heat

- 20 ~

and pressure is applied, the fibers ~use together, resulting
in strengthening of the web structure. Also, Minto et al.,
U.S. Patent No. 4,469,734, discloses a method to prepare
wipes from a melt-blown web, the web being formed or provided
with apextures by, for example, hot needling or by passing
the web between differentially speeded rolls. The disclosure
of Minto et al., U.S. Patent No. 4,469,734, is hereby
incorporated by reference.
The nonwoven webs produced by the present process are
useful in a var;ety of ways. For example, the w~bs may be
used in apparel, hydrophilic wipes, napkins, and personal
care items. They may also be used as absorbents for water,
urine, and similar fluids, and as compositions for the
release of bactericides, drugs, fungicides, and insecticides.
As such, they are ideal as absorptive liners for garments or
for dressings.
Furthermore, they may be used as filters for the
removal of particulate matter or water, or as filters for
removing acidic or basic materials. In addition, they may be
used in ion exchange resins, in odor removers, in battery
separators, and in barrier composites. Another use is in
making nonwoven fabric laminates, for example by
hydroentanglement.
Moreover, the present melt-blown materials are useful
as reinforcing agents for plastics, adhesives, concrete, and
the like, and in geotextile applications. Also, they can be
conductive or may be made conductive by the inclusion of
conductive materials or by metal plating, and may then be
used in EMI shielding or microwave-interactive heating
constructions. In short, ~he present melt-blown materials
may be used for just about anything that conventional
nonwoven webs can be used for, as well as for many specific
applications particularly requiring a hydrophilic nonwoven
web.

s~
- 21 -

The following examples illustrate the present process
for preparing a nonwoven web and the properties thereof.
EXaMPLES 1-5
A block copolymer with a sample designation Hydrofil~
87-0063, having a number average molecular weight of about
14,000, and the apparent viscosities shown in Figure 1, was
obtained from the Allied Fibers Division of the Allied
Corporation
It is believed that Hydrofil~ 87-0063 comprises:
(a) about 15% of the amine-ended polyethylene oxide
of the general formula
IH3 IH3 ICH3
__HNCHCH2 (OCHCH2)a (OCH2CH2)b--_(OCH2CH)c --NH-----
wherein a plus c is about 2 to about 3 and b is
about 8 to about 140, and
(b) about 85% of nylon 6.
As seen in Figure 1, the Hydrofil~ composition used in
these examples starts to thermally degrade at about 303C.
Surprisingly, however, the Hydrofil~ composition was in fact
melt-blown into continuous webs using a melt-blowing method
similar to that disclosed in Buntin, U.S. Patent No.
3,972,759, at the melt temperatures and melt-blowing
parameters shown in Table IV.

Table IV. M~lt ~l~wrn~ P~ b ~-
auipment: One inch diameter extruder with L/D of 18/1.
Ten inch die with 25 spinneret holes per inch.
Resin: Hydrofil~ 87-0063
Ex.l Ex.2 Ex.3 Ex.4 Ex.5
Melt TemPerature (C ?: 338 335 310 310 318
Throu~hout (q/hole/min~ 0.51 0.23 0.23 0.35
Collector Speed
~meters/min): 2.0 2.7 8.4 4.2 4.2
Extruder S~eed (RPM): 90 90 75 75 90




, . . .

- 22 -


The physical properties of the derived webs are set
forth in Table V. Unless stated otherwise, the following
test methods were used to generate the values seen in Table
V.
Basis Weiqht
Samples were cut using a razor blade and a metal
template (50 x 200 millimeters) and the sample weighed to the
nearest 0.001 gram. The specimens were dried and
equilibrated to ambient conditions before weighing. The
basis weight is reported, in grams per square meter (g/m2),
as the weight of the sample x 100.
CaliPer
Web thickness was measured using an Ames gauge (Model
79-011; Ames Inc., Waltham, MA) with zero load.
Gurle~ Permeability
Permeability was measured using a Gurley Permeometer
(Model 4301; Teledyne Gurley, Troy, NY) for a two-inch-
diameter disc of the web with an air pressure of 0.5 inch of
water. Data are reported as the flow rate in cubic feet per
minute (ft3/min) through one square foot of material.
Pore Number
The pore number was measured as the minimum air
pressure, in inches of water, necessary to force a bubble of
air through a 0.75-inch-diameter disc of web supporting a
column of isopropanol 1.375 inches high. The equipment used
is similar to the simplified setup described in ASTM F316-80.
Tensile Measurements
Tensile strength (maximum strength) and elongation at
break were measured using an Ins~ron tensile tester (Model
1101, Instron Corp., Canton, MA). Jaw spacings and speeds
were a~ follows:
Sample Width Jaw Size Spacing Speed
(in) (in) (in) (in/min)
Strip 1.0 1.0 3.0 12

- 23 ~

Samples were tested in the machine direction (MD) and
the cross-machine direction (CD).
Tear Strenqth
Tear strength was measured using a Thwing-Albert
Elmendorf Tear Tester (Model 60-32), using samples 3 inches
(CD) by 2.5 inches (MD) which were torn parallel to the
machine direction. One ply samples were tested using a 1600
g pendulum. The instrument scale was calibrated in
percentages of the weight of the pendulum, and the Elmendorf
tear, in grams, was given by the scale reading x 1600.
In addition to the properties discussed in Table V, all
the webs were instantly wettable by a drop of cold water, a
property which was retained even after repeated rinsing with
water. When used as wipes, the samples absorbed and retained
water readily and exhibited a desirable, mild abrasive action
on the wiped surface. The webs also were durable and
retained excellent mechanical integrity, even when wet.
It will be appreciated that various changes may be made
in detail regarding the materials, processes, and products
described herein without departing from the invention as
defined in the appended claims.




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