CA2071202A1 - Waterproofing of polyester fiberfill - Google Patents

Abstract

A waterproof hydrophilic copolyetherester film having a high water vapor transmission rate can be secured surprisingly well to polyester fiberfill batting, so provides advantages in processing, and provides improved comfort to the wearer when the composite is used in apparel.

Description

7~202 TITLE
IMPROVED WATERPROOFING OF POLYESTER FIBERFILL

CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of copending Application Serial No. 07/449,615, filed by Frankosky on December 12, 1989.

FIELD OF INVENTION
This invention concerns improvements in and relating to providing polyester fiberfill with a waterproof coating layer, especially for use in apparel.

BAC~GROUND
Polyester fiberfill (sometimes referred to as polye~ter fiberfilling material) has become well accepted as a reasonably inexpensive filling and/or insulating material, and is manufactured and used in large quantities for pillows, cushions and other furnishing materials, including bedding materials, and in apparel. Polyester fiberfill `~ batting is used commercially i~ many apparel articles because it is an efficient and economic alternative to down and feather insulation, and it is relatively insensitive to -` moisture. It is, however, desirable to prevent intrusion by water, ~or example on cold rainy days, as intrusion by water would detract from the wearer's comfort. This has been the '?, . ._~
objec~ive. : ;
Conventional waterproofing that prevents -perspiration from escaping is not the answer, as this 30 ~perspiration would eventually collect as a liquid and detract from comfort. Recently, therefore, coatings of -various types, including films, have been developed to allow water vapor to pass, but not allow liquid to pass. ~
Generally, such ~ilms have been applied or attached to fabrics for use in making "waterproof/breathable" apparel.
Such apparel has required, in practice, special seam-sealing wherever fabrics have been joined or attached, such as for . .
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W091tO9166 PCT/US90/07051 ~ 2 -arms and pockets. This spPcial seam-sealing has been expensive and has limited design possibilities, and, for sheer fabrics, has been aesthetically objectionable. Also, recently, waterproof/breathable film has been attached to a scrim to be used as a drop-in liner; this approach gave more design freedom and reduced the amount of seam-sealing needed, but the films required special treatment to prepaxe them for lamination to the scrim and were attached to the scrim in a separate step.
To improve the aesthetics of polyester fiberfill, it has generally been preferred to "slicken" the fiberfill with a coating of durable (e.g., wash-resistant) coating, that has usually been a silicone, i.e., a cured polysiloxane, as disclosed, e.g., by Hofmann, U.S. Patent No. 3,271,189, Mead et al., U.S. Patent No. 3,454,422, Ryan, U.S. Patent No. 3,488,217, Salamon et al., U.S. Patent No.
4,146,674, Pamm, U.S. Patent No. 4,281,042, Frankosky, U.S.
Patent No 4,304,817, and Takemoto Oil & Fat Co. Ltd., Japanese Published Patent Application No. 58-214,58S (1983).
The slickener has long presented serious problems in obtaining good adhesion, as discussed in several of these references, such as Pamm and Frankosky.
So, it has long been desirable to provide a practical solution to this problem of waterproofing polyester fiberfill batts, as such or in the form of garments or other articles filled with polyester fiberfill, especially slic~ened polyester fiberfill, without the defects mentioned.
Another problem has been leakage of the polyester fiberfill through surrounding shell fabric, as described by LeVan in U.S. Patent No. 4,869,771, which again mentions the problem of getting materials-to adhere-to slickened -polyester fiberfill.

- SUMMARY OF INVENTION` -`
- Surprisingly, we have now found, according to the present invention, that a film of a particular copolyetherester elastomer that is hydrophilic can be ~, .

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- 3 ~ 1202 secured to slickened polyester fiberfill, e.g. in the form of a batt, with attendant advantages, as will be evident hereinafter.
So, according to one aspect of the invention, there is provided a batt of polyester fiberfill, or a garment or other article filled with polyester fiberfill, wherein the polyester fiberfill is secured to a continuous flexible layer of a waterproof hydrophilic elastomer having a water vapor transmission rate of at least 3500 gm.mil/m2/24hrs, according to ASTME96-66 (procedure BW), said hydrophilic elastomer being a copolyetherester elastomer or a mixture of two or more copolyetherester elastomers having a multiplicity of long-chain ester units and short-chain ester units joined head-to-tail through ester linkages, said long-chain ester units being represented by the formula.
~, O O
: 20 -OGO-CRC-and said short-chain ester units being represented by the ' formula: ' :
:. O O
-ODO-~RC-wherein G is a divalent radical remaining after the removal of terminal hydroxyl groups from a poly(alkylene oxide) : glycol having an average-molecular weight'of about 400-3500, `. .:and further,-the amount of ethylene oxide'groups incoporated in.the copolyetherester or m'ixtùre.of two or more . copolyetheresters by the poly(alkyl'ene oxide) glycol is- from .about-25-68 weight percent based upon-the total'weight of ~; the.copolyetherester or mixture'of two'or more~
copolyetheresters: R-.:is a divalent-radical-rema'i'ning:~after removal'of carboxyl groups from~dicarboxylic`aci'd having--`a -~
'' molecular weight less than 300,--D is a`divalent radical '` remaining after removal of hydroxyl groups'from a diol ' having a molecular weight less than about 250; and said hydrophilic copolyetherester or mixture of two or more -copolyetheresters has from about 25-80 weight percent short-" ' . ' : I

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WO91J09166 PCT/US90~070~1 ~Q~ ~q~.je~J ~ 4 ~
chaln este unlts.
Advantageously, if desired, the fiberfill issecured to the continuous layer of the hydrophilic elastomer by an intervening layer of a hydrophobic elastomer having a water vapor transmission rate of 400-2S00 gm.mil/m2/24hrs, preferably about 800-1200 gm.mil/m2/24hrs, said hydrophobic elastomer is a copolyetherester having a multiplicity of recurring long chain ester units and short-chain ester units, said long-chain ester units being represented by the formula O O
-OGO-CRC-and said short-chain ester units being represented by the :Eormula:
O O
-ODO-CRC-where G is a divalent radical remaining after the removal of terminal hydroxyl groups from a poly(alkylene oxide) glycol having an average molecular weight of about 400-3500, the amount of ethylene oxide groups incorporated in the copolyetherester by the poly(alkylene oxide)glycol is not greater than about 20 weight percent; R is a di~alent radical. remaining after removal of carboxyl groups from a dicarboxylic acid having a molecular weight less than 300; D
is a divalent radical remaining after removal of hydroxyl groups..from.a diol having a molecular weight less than about 250, and wherein said hydrophobic elastomer preferably has about 25-80 weight percent short-chain ester units. The fiberfill may advantageously be bonded intermittently to the layer of hydrophobic elastomers.by spot-bonding or.in other disconti~nuous-manner-,-preferably by..use of~binder.fibers .
that are of~lower melting point. -i~
. ;~It~will.be-understood that such aforesaid..~
elastomers may be unitary copolyetherester elastomers, or mixtures of two or more copolyetherester elastomers if desired.
Thus, in one aspect of the invention, the flexible . .

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~ 5 ~ 2~ ~202 film may comprise more than one elastomer layer. One layer is a hydrophilic elastomer layer, as above. A second layer may be coextruded with the first and may be a hydrophobic elastomer, such as a copolyetherester containing 20.3 weight percent 1.4 butylene terephthalate, 7.9 weight percent 1,4 butylene isophthalate, 51.7 weight percent poly(tetramethylene ether) isophthalate and 20.1 weight percent poly(tetramethylenP ether) terephthalate wherein the poly(tetramethylene ether) glycol used had a molecular weight of 2000. Such second layer is more hydrophobic and has a lower melting point, which helps adhesion.
The polyester fiberfill is preferably slickened.
The batts etc are preferably of density within the range of 0.5 to 1 pound per cubic foot (about 0.008 to 0.016gm/cu cm), but may be of density up to about 1.5, or up to about 2 lb/cu ft. (about 0.025, or about 0.03 gm/cu cm.) ~he waterproof fiberfill composites have shown an advantage in their ability to avoid delamination upon stretching and ~lexing in use over an extended period, such as would be encountered while the apparel is being worn.
Other aspects and advantages of the invention will appear hereinafter.

DETAILED DESCRIPTION OF_'l'HE IN~lENq~ION
The invention is expected to be particularly useful with the slickened fiberfill described in the foregoing references, the disclosures of all of which are hereby incorporated herein by reference, in particular such blends as described by Frankosky, in U.S. Patent No.
4,304,817. - -Preferred hydrophilic copolyetherester elastomers are those hydrophilic elastomers more particularly described by Ostapchenko in U.S. Patent No. 4,725,481, *he disclosure of which is also hereby specifically incorporated by reference, being an improvement over the art cited therein, such as Vrouenraets et al., U.S. Patent No. 4,493,870 and Japanese Patent Application No. 50-35623, published ` October 1, 1976, disclosing less preferred , .

W091tO9166 PCT/US90/07051 ~ 6 - -copolyetheresters. In practice, it has been considered necessary to secure films of such copolyetherester elastomers by adhesive techniques, as indicated therein.
This is because other methsds to secure the films have not been found adequate, in practice. We have found that, when such films have been directly extrud~d onto a fabric, such as a nonwoven scrim of polyethylene terephthalate fibers, the composites are insufficiently bonded in the sense that, in practice, during subsequent stretching and flexing such as occurs during use, spot delamination occurs, i.e. the bonds between the film and the fabric break locally, so the integrity of such a composite no longer exists all over the interface between the fabric and the film. Surprisingly, however, according to the present invention, polyester fiberfill battings can be better bonded overall to such copolyetherester films, in the sense that the integrity of the interfacial bond stands up better in practice to repeated stretching and flexing. A suitable batt of polyester fiberfill preferably has a low density up to about 0.5 to l lb/cu ft, but the density may be up to about 1.5, or even up to about 2 lb/cu ft (corresponding to about 0.008 to 0.016, up to about 0.025, or even about 0.03 gm/cu cm).
A batt of fiberfill is not so dense as most fabrics, much less dense even than a nonwoven ligl~tweight scrim (a nonwoven lightweight scrim fabric of spun bonded polyethylene terephthalate such as was used in Example l of -Qstapchenko Patent No. 4,7Z5,481 being about 7 to 7.5 lb/cu ft, i.e. about 0.12 gm/cu cm, for example), and presents fewer contact points to a film. One may speculate that such differences could be important reason for the different and surprising behaviors in practice, although this invention is : not--intended to be limited to any theory.
-The composite according to the~invention provides an apparel material that combines both thermal insulation and a barrier to penetration by liguid (water), while allowing water vapor to escape. Preferred materials combine ~` strength with good aesthetics. The materials may be made easily by extrusion of the hot tacky film onto the batting .~ : . , ; ' WO91/0~166 PCT/US90/07~51 ~ 7 2071 2Q2 or by a laminating process, such as has been used previously, whichever is desired. When a pre-formed film is laminated to the batting, it is possible to use a solvent-based adhesive, but a low melting adhesive is ganerally preferred, in the form of binder fibers, spot-adhesion or other technique of avoiding a continuous layer of adhesive bonding to the film. The materials may be processed conventionally into garments or articles other than apparel, as desired. An important advantage over prior suggestions is the ability of the new composites to have their seams sealed ultrasonicallyO
The invention will now be described in the following Examples. All parts and percentages are by weight, unless otherwise indicated. In every case, satisfactory adhesion was obtained between the batting and the waterproof film.

Exam~le 1 In Example 1, a 50 yard commercial sample of 3.0 oz/s~ yd bonded batting (density about 1 lb/cu ft), made from a triple blend of silicone slickened, dry and binder fibers, was united with a film of a copolyetherester elastomer consisting of 45% butylene terephthalate and 55%
of a mixture consisting of 60% polyethylene oxide (molecular weight = 2000) terephthalate and 40% of polyethylene . oxide/polypropylene oxide (molecular weight = 2150, ethylene oxide content = 25%~ terephthalate as the film.was-freshly extruded.by a slit die,extruder maintained at 229C and a die lip opening of about 10 mils. The linear speed of extrusion was about 2 yards per minute, while the take-up ~~~
rolls were about 15 times faster (30 yards per minute)j~
A lthereby reducing the film thickness.to about 0,7 milj- by..the . time thé film was coated on to-the batting. The,first~-?
. .contact.~with the-batting occurred.at the.nip between~.the-~two take~up rolls; the lower roll preheated the batting as it carried it to meet the film; the upper (pressure) roll provided a means to drive the film and batting together while cooling the film to cause it to solidify. For this .

~ 8 -3.0 ounce batting, adequate adhesion was obtained with negligible loss in batting bulk when the roll carrying the batting was maintained at 80C and the pressure/quench roll was maintained at 60C.
' ~ .
- ~Example 2 ~ In Exampls 2,: all conditions were the same as for Example 1 except that 4.5-ounce batting was used which required different temperatures for the first contact rolls.
The temperature of the lower roll carrying the batting was 93C, while the upper pressure roll was maintained at 60C.

Example 3 In Example 3, film making was separated from lamination. A bilayer film was made by coextrudi~g copolyetherester elastomers (A) and (B) where (A) consisted of 45% butylene terephthalate and 55~ of a mixture consisting of 60% polyethylene oxide (molecular weight =
2000) terephthalate and 40~ of polyethylene oxide/polypropylene oxide ~molecular weight = 2150, ethylene oxide content = 25%) terephthalate, and (B) consisted of 20.3% 1,4-butylene terephthalate, 7.9~ 1j4-butylene isophthalate, 51.7~ poly(tetramethylene ether) terephthalate and 20.1% poly(tetramethylene ether) isophthalate wherein the poly(tecramethylene ather) glycol used had a ~olecular weight of 2000. The coextruded ~ilm was prepa-red using a `2.5 inch (6.4 cm) diameter~extruder'to feed copolyetherester ¦
A and a-l.5 (3.8 cm)inch`'diameter'!extruder;to feed~
copolyetherester B to a co~bining''bloc~ to join the ~' 30 respective polymer melts in a laminar fashion prior to extrusion through a.sl~t die. ~he 1.5 inch diameter- ' ;: !.-. extruder'was maintained~at-215C~, andi~the 2.5- inchi'diameter screw.'was màintained~'at-205C.': The'die-lip opening~was-:~set at~.lO mils( 0;25 mm) and'the'die temperature wa~ maintalned at 215C. Coextruded-~ilm was produced at a rate of 18-yards (16.6 meters)/min to yield a final film thickness of 0.7 mil (0.018 mm). -The ratio'of extruder speeds was maintained such that the thickness of copolymer (A) was 0.6 , - , ; ~ . , , .;, .: . . . . ..
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'~ : ` ' ,. :. ' -9~ 7~2~2 mils and that of copolymer (B) was 0.1 mils.
In a separate operation, a 10 yard commercial sample of batting, like in Example 2, was co fed with the bilayer film and a non-woven webbing of-commercially - -available low-melting polyester binder fiber into a ~lat bed laminating unit which could heat the components from above and below by contact heat from endless belts coated with Teflo~ TFE fluorocarbon. The spacing between the belts was adjusted to avoid compression of the batting. The film contacted the bottom belt and was arranged so that copolymer (B) faced the batting. The adhesive nonwoven was a 0.63 oz/sq yd polyester fabxic having a 135C mp, available under the trade name "Spunfab Type PE204", and was placed between the film and the batting. The sandwich was processed at about 7 yards (6.4 meters) per minute using a belt temperature of 150C.

Example 4 In Example 4, all conditions for film making were the same as for Example 3. For the laminating step, a 10 yard commercial sample of batting was co-fed into the flat-bed laminating unit without the bincler fiber webbing, and with the bilayer film. In place of the nonwoven binder fiber webbing, ~Bostik'~ 5178 Polyest:er powder was applied at a rate of about 0.5 oz/sq yd onto the film surface. The sandwich was proces~ed at about 7 yards ~6.4 meters) per minute using a belt ~emperature of 150C.
Griltex EMS 6D2-2 may be used as an adhesive powder, in tead of the "Bostik" 5178 Polyester powder.
It is not necessary to apply as much adhesive, and good adhesion has been obtained by applying as little as 0.25 oz/sq yd, it being understood that the precise amount may depend on various factors, such as are known in the art, e.g. type and pattern of application, intended use, aesthetics and materials selected.
These composites have shown excellent waterproof/breathable gualities, and have not shown a tendency toward spot-delamination such as has been ' ~'.' ~; ~

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WO91/Ogl66 PCT/U~90/07051 encountered with film bonded to a nonwoven lightweight scrim fabric of spunbonded polyethylene terephthalate that was merely extrusion-coated, i.e. unless th~ scrim fabric had been spot-adhered using an adhesive to provide a satisfactory bond between the film and the fabric. The film also effectively seals the fiberfill within the outer layer.

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Claims (4)

Claims

1. A slickened polyester fiberfill batt or a garment or other article filled with slickened polyester fiberfill, wherein the slickened polyester fiberfill is secured to a continuous flexible layer of a waterproof hydrophilic elastomer having a water vapor transmission rate of at least 3500 gm.mil/m2/24hrs, according to ASTM E96-66 (Procedure BW), said hydrophilic elastomer being a copolyetherester elastomer or a mixture of two or more copolyetherester elastomers having a multiplicity of long-chain ester units and short-chain ester units joined head-to-tail through ester linkages, said long-chain ester units being represented by the formula (I) and said short-chain ester units being represented by the formula:
(II) where G is a divalent radical remaining after the removal of terminal hydroxyl groups from a poly(alkylene oxide) glycol having an average molecular weight of about 400-3500, and further, the amount of ethylene oxide groups incorporated in the copolyetherester or mixture of two or more copolyetheresters by the poly(alkylene oxide) glycol is from about 25-68 weight percent based upon the total weight of the copolyetherester or mixture of two or more copolyetheresters; R is a divalent radical remaining after removing of carboxyl groups from a dicarboxylic acid having a molecular weight less than 300; D is a divalent radical remaining after removal of hydroxyl groups from a diol having a molecular weight less than about 250; and said hydrophilic copolyetherester or mixture of two or more copolyetheresters has from about 25-80 weight percent short-chain ester units.

2. A slickened polyester fiberfill batt or garment or other article according to Claim 1, wherein the fiberfill is secured to said continuous flexible layer of said hydrophilic elastomer via an intervening layer of a hydrophobic elastomer having a water vapor transmission rate of 400-2500 gm.mil/m2/24hrs, said hydrophobic elastomer is a copolyetherester elastomer or a mixture of two or more copolyetherester elastomers having a multiplicity of recurring long-chain ester units and short-chain ester units, said long-chain ester units being represented by the formula:
(I) and said short-chain ester units being represented by the formula:
(II) where G is a divalent radical remaining after the removal of terminal hydroxyl groups from a poly(alkylene oxide) glycol having an average molecular weight of about 400-3500, the amount of ethylene oxide groups incorporated in the copolyetherester by the poly(alkylene oxide)glycol is not greater than about 20 weight percent; R is a divalent radical remaining after removal of carboxyl groups from a dicarboxylic acid having a molecular weight less than 300;
and D is a divalent radical remaining after removal of hydroxyl groups from a diol having a molecular weight less than about 250; and said hydrophobic copolyetherester or mixture of two or more copolyetheresters has from about 25-80 weight percent short-chain ester units.

3. A slickened polyester fiberfill batt or garment or other article according to Claim 2, wherein the fiberfill is discontinuously bonded to said hydrophobic elastomer by an adhesive.

4. A slickened polyester fiberfill batt or garment or other article according to Claim 3, wherein said hydrophobic elastomer is bonded to the fiberfill by means of binder fibers having a melting point that is lower than that of the polyester fiberfill and lower than that of said hydrophobic elastomer.