CA2053520A1 - Meltblown hydrophilic web made from copolymer of an amine-ended polyethylene oxide and a polyamide - Google Patents
Meltblown hydrophilic web made from copolymer of an amine-ended polyethylene oxide and a polyamideInfo
- Publication number
- CA2053520A1 CA2053520A1 CA 2053520 CA2053520A CA2053520A1 CA 2053520 A1 CA2053520 A1 CA 2053520A1 CA 2053520 CA2053520 CA 2053520 CA 2053520 A CA2053520 A CA 2053520A CA 2053520 A1 CA2053520 A1 CA 2053520A1
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- CA
- Canada
- Prior art keywords
- melt
- poly
- nylon
- amine
- block copolymer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
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- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
- D04H1/56—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving in association with fibre formation, e.g. immediately following extrusion of staple fibres
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D01D5/00—Formation of filaments, threads, or the like
- D01D5/08—Melt spinning methods
- D01D5/098—Melt spinning methods with simultaneous stretching
- D01D5/0985—Melt spinning methods with simultaneous stretching by means of a flowing gas (e.g. melt-blowing)
-
- D—TEXTILES; PAPER
- D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
- D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
- D01F6/78—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products
- D01F6/82—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from copolycondensation products from polyester amides or polyether amides
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/42—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
Landscapes
- Engineering & Computer Science (AREA)
- Textile Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Mechanical Engineering (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Nonwoven Fabrics (AREA)
- Artificial Filaments (AREA)
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.
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.) - - , ' _ 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 __XNCHCH2 (OCHCH2)a (OCH2CH2~b----(OCH2CH)C___NH___ .
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 .
.
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 _-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:
(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.
`
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 ~, 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~
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 __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 , . . .
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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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.) - - , ' _ 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 __XNCHCH2 (OCHCH2)a (OCH2CH2~b----(OCH2CH)C___NH___ .
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 .
.
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 _-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:
(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.
`
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 ~, 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~
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 __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 , . . .
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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Claims (41)
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.
(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 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 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.
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 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.
17. The process according to claim 1, wherein the composition is melt-blown at a temperature of from about 310°
to about 340°C.
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.
(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 wherein the sum of a plus c ranges from about 2 to about 20, and b is from about 5 to about 500.
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.
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 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.
(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.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US61057090A | 1990-11-08 | 1990-11-08 | |
| US07/610,570 | 1990-11-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2053520A1 true CA2053520A1 (en) | 1992-05-09 |
Family
ID=24445560
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2053520 Abandoned CA2053520A1 (en) | 1990-11-08 | 1991-10-16 | Meltblown hydrophilic web made from copolymer of an amine-ended polyethylene oxide and a polyamide |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0484952A1 (en) |
| JP (1) | JPH04327254A (en) |
| CA (1) | CA2053520A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6057024A (en) * | 1997-10-31 | 2000-05-02 | Kimberly-Clark Worldwide, Inc. | Composite elastic material with ribbon-shaped filaments |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6369293B1 (en) | 1998-11-04 | 2002-04-09 | Kimberly-Clark Worldwide, Inc. | Absorbent composition including an uncrosslinked polymer |
| US6580015B2 (en) | 1999-09-14 | 2003-06-17 | Kimberly-Clark Worldwide, Inc. | Absorbent composition including an uncrosslinked polymer |
| US20100041804A1 (en) * | 2008-08-13 | 2010-02-18 | Brands Gerrit J | Fabricating fibers |
| KR20150067761A (en) * | 2012-10-10 | 2015-06-18 | 인비스타 테크놀러지스 에스.에이 알.엘. | Polyamide compositions and processes |
| ITFI20130162A1 (en) * | 2013-07-04 | 2015-01-05 | Golden Lady Co Spa | "METHOD FOR THE PRODUCTION OF A SYNTHETIC WIRE RETURNED WITH HUMIDITY AND THREAD OBTAINED" |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4923454A (en) * | 1988-01-20 | 1990-05-08 | The Procter & Gamble Company | Microfiber-containing absorbent structures and absorbent articles |
-
1991
- 1991-10-16 CA CA 2053520 patent/CA2053520A1/en not_active Abandoned
- 1991-11-07 JP JP29141591A patent/JPH04327254A/en active Pending
- 1991-11-07 EP EP91119017A patent/EP0484952A1/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6057024A (en) * | 1997-10-31 | 2000-05-02 | Kimberly-Clark Worldwide, Inc. | Composite elastic material with ribbon-shaped filaments |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0484952A1 (en) | 1992-05-13 |
| JPH04327254A (en) | 1992-11-16 |
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