JP5717733B2 - High-strength fabric made of thin gauge constant compression elastic fiber - Google Patents

Description

FIELD OF THE INVENTION This invention relates to high strength fabrics made from thin gauge, constant compression elastic fibers. Garments made of constant compression elastic fibers have a very comfortable feel for the wearer. These garments also have resistance to perforation due to high strength fabrics made of elastic fibers.

BACKGROUND OF THE INVENTION In recent years, with the changing lifestyles around the world, there has been an increasing demand for the expansion of fabric functions that have evolved beyond the basic function of heat insulation. One such function being pursued is a thinner gauge fabric that does not sacrifice fabric strength and quality. This thinner gauge cloth reduces the storage volume, reduces the “bulk height” feeling, and eliminates external visibility through the outer garment in the case of underwear.

  Synthetic elastic fibers (SEF) are usually made from a polymer having soft and hard segments to obtain elasticity. The polymer with hard and soft segments is usually a poly (ether-amide), such as Pebax®, or a copolyester, such as Hytrel®, or a thermoplastic polyurethane, such as Estane®. is there. However, very high elongation SEFs typically utilize hard and soft segmented polymers, such as dry-spun polyurethane (Lycra®) or melt-spun thermoplastic polyurethane (Estane®). These SEFs vary from low to very high elongation at break, but all generally describe having a modulus that increases exponentially with increasing elongation (stress). be able to.

  Melt spun TPU fibers offer several advantages over dry spun polyurethane based fibers in that no solvent is used in the melt spinning process. On the other hand, in the dry spinning process, the polymer is dissolved in a solvent and spun. The solvent then partially evaporates from the fiber. It is very difficult to completely remove all of the solvent from dry-spun fibers. In order to facilitate the removal of solvent from dry-spun fibers, they are usually sized and bundled together to create multifilament (ribbon-like) fibers. This makes the physical size larger for a given denier compared to melt spun fibers. These physical properties increase the bulk of the fabric and the nature of the multifilament bundle reduces comfort.

Melt spun TPU fibers are made by melt spinning a TPU polymer. The TPU polymer has three components: (a) a hydroxyl-terminated intermediate, usually a polyether or polyester endcapped with hydroxyl groups, (b) a polyisocyanate, such as a diisocyanate, and (c) a short chain hydroxyl. Made from the reaction of a terminal chain extender. The hydroxyl-terminated intermediate forms the soft segment of the TPU polymer, and the polyisocyanate and chain extender form the hard segment of the TPU polymer. When combined with soft and hard segments, the TPU polymer gains elastic properties. TPU polymers are often lightly cross-linked by using prepolymers endcapped with polyisocyanates to obtain enhanced properties. The cross-linking material is added to the melted TPU polymer during fiber spinning.

  It is desirable to have TPU elastic fibers that have a relatively constant compressibility between zero and 250% elongation, and to make constant compressibility garments and / or fabrics containing such TPU fibers. It is also desirable that these constant compressibility fabrics be thin gauge and have high puncture resistance. Garments made from such fabrics will provide the wearer with greater comfort and reliability.

(Summary of Invention)
Thin gauge, constant compressibility, high strength with a critical elongation of at least 400%, relatively flat and / or with a constant modulus during loading and unloading cycles between 100% and 200% elongation It is an object of the present invention to provide fibers. This flat and / or constant modulus is less than 0.023 gram weight per denier at 100% elongation and less than 0.023 gram weight per denier at 150% elongation and 200% elongation during the load cycle. At less than 0.03 gram weight per denier at 200% elongation and less than 0.018 gram weight per denier at 150% elongation, This is also evidenced by a stress of less than 0.015 grams per denier at 100% elongation.

  Exemplary fibers are made by melt spinning a thermoplastic polyurethane polymer, preferably a polyester polyurethane polymer. The fibers are lightly crosslinked during the melt spinning process, preferably by adding 5 to 20 weight percent crosslinking agent to the polymer melt.

  The process of manufacturing the fiber includes a melt spinning process in which the fiber is formed by passing a polymer melt through a spinneret. The speed of the fiber exiting the spinneret is relatively close to the speed at which the fiber is wound on the bobbin. That is, the fiber should be wound on the bobbin at a speed that is no greater than 50%, preferably 20%, more preferably no greater than 10% of the speed at which the fiber exits the spinneret.

  It is another object of the present invention to produce a fabric having thin gauge, constant compressibility fibers. In an exemplary embodiment, the fabric is made by combining (eg, knitting or weaving) elastic fibers with hard fibers, such as nylon and / or polyester fibers. The fabric made from this new fiber also has a high burst strength.

Clothing for clothing, such as underwear, is made from the elastic fibers. Such a garment provides the wearer with very good comfort.
For example, the present invention provides the following.
(Item 1)
A thin gauge, constant compressibility, high burst strength elastic fiber having a critical elongation of at least 400% and a relatively flat modulus in loading and unloading cycles between 100% and 200% elongation.
(Item 2)
The fiber of item 1, wherein the 40 denier monofilament fiber has a width of less than 100 microns.
(Item 3)
The fiber of item 1, wherein the fiber having a denier of 70 is made into a fabric and when the fabric is tested for puncture strength according to ASTM D751, the fabric has a load at break greater than 6 pounds.
(Item 4)
Item 2. The fiber according to Item 1, wherein the fiber is a thermoplastic polyurethane fiber.
(Item 5)
Item 5. The fiber according to item 4, wherein the fiber is a polyester thermoplastic polyurethane.
(Item 6)
Item 6. The fiber according to Item 5, wherein the fiber is crosslinked with a polyether crosslinking agent.
(Item 7)
6. The fiber of item 5, wherein the polyester thermoplastic polyurethane has a weight average molecular weight of 200,000 to 700,000 daltons.
(Item 8)
Item 7. The fiber of item 6, wherein the crosslinking agent is 5 to 20 weight percent of the total weight of the polyester thermoplastic polyurethane and the crosslinking agent.
(Item 9)
Item 9. The fiber of item 8, wherein the cross-linking agent is 8 to 12 weight percent of the total weight of the polyester thermoplastic polyurethane and the cross-linking agent.
(Item 10)
A fabric comprising at least two different fibers, wherein at least one of the fibers is a thermoplastic polyurethane fiber, at least one of the fibers is a hard fiber, and the thermoplastic polyurethane fiber extends from 100 to 200 percent A fabric having a relatively flat stress-strain curve between rates.
(Item 11)
Item 11. The fabric according to Item 10, wherein the fabric is composed of two yarns of thermoplastic polyurethane fibers per yarn of hard fibers.
(Item 12)
Item 11. The fabric of item 10, wherein the thermoplastic polyurethane fiber has a denier of 20 to 600.
(Item 13)
Item 13. The fabric of item 12, wherein the thermoplastic polyurethane fiber has a denier of 70 to 360.
(Item 14)
Item 11. The fabric according to Item 10, wherein the hard fiber is selected from the group consisting of nylon and polyester.
(Item 15)
Item 15. The fabric of item 14, wherein the hard fibers have a denier of about 70 and the thermoplastic polyurethane fibers have a denier of about 140.
(Item 16)
An article for clothing comprising the fabric according to item 10.
(Item 17)
Item 17. The clothing item according to Item 16, wherein the article is underwear.
(Item 18)
Item 18. The clothing item according to Item 17, wherein the article is a brassiere.
(Item 19)
A process for producing an elastic fiber having a relatively flat modulus in loading and unloading cycles between 100% and 200% elongation,
(A) melt spinning a thermoplastic elastomer polymer through a spinneret; and
(B) winding the elastic fiber around a spool at a winding speed not greater than 50% of the polymer melt speed exiting the spinneret
Including processes.
(Item 20)
20. The process of item 19, wherein the winding speed is not greater than 20% of the polymer melt rate exiting the spinneret.
(Item 21)
Item 21. The process of item 20, wherein the winding speed is not greater than 10% of the polymer melt rate exiting the spinneret.
(Item 22)
20. A process according to item 19, wherein the thermoplastic elastomer polymer is a thermoplastic polyurethane.

FIG. 1 is a photomicrograph of 70 denier multifilament commercial dry-spun polyurethane fiber. FIG. 2 is a photomicrograph of a 70 denier melt spun constant compression ratio thermoplastic polyurethane fiber of the present invention. FIG. 3 is a graph showing denier on the X axis and the square of the fiber width (square microns) on the Y axis. The fibers of the present invention are compared to commercial dry spinning fibers.

  The fibers of the present invention are made from a thermoplastic elastomer. A preferred thermoplastic elastomer is a thermoplastic polyurethane polymer (TPU). Although the present invention is described using TPU, it should be understood that this is only one embodiment and that other thermoplastic elastomers may be used by those skilled in the art.

The type of TPU polymer used in the present invention may be any conventional TPU polymer known in the art and literature as long as the TPU polymer has the appropriate molecular weight. TPU polymers are generally prepared by reacting a polyisocyanate with one or more chain extenders with an intermediate such as a hydroxyl-terminated polyester, a hydroxyl-terminated polyether, a hydroxyl-terminated polycarbonate, or mixtures thereof. All of these are well known to those skilled in the art.

The hydroxyl-terminated polyester intermediate generally has a number average molecular weight (M _n ) of about 500 to about 10,000, desirably about 700 to about 5,000, preferably about 700 to about 4,000, A linear polyester having an acid value of less than .3, preferably less than 0.8. The molecular weight is determined by terminal functional group assay and is related to the number average molecular weight. The polymer can be (1) by an esterification reaction of one or more glycols with one or more dicarboxylic acids or acid anhydrides, or (2) transesterification, ie one or more glycols with esters of dicarboxylic acids. Produced by reaction. In order to obtain a linear chain in which the terminal hydroxyl groups are predominant, a molar ratio of glycol of greater than 1 mole to acid is generally preferred. Suitable polyester intermediates also include polycaprolactones made from various lactones, such as usually ε-caprolactone and a difunctional initiator such as diethylene glycol. The desired polyester dicarboxylic acid may be aliphatic, cycloaliphatic, aromatic, or combinations thereof. Suitable dicarboxylic acids, which may be used alone or in a mixture, generally have a total of 4 to 15 carbon atoms and include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelain Acid, sebacic acid, dodecanedioic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, and the like. Anhydrides of the above dicarboxylic acids such as phthalic anhydride, tetrahydrophthalic anhydride, or the like may also be used. Adipic acid is the preferred acid. The glycol that reacts to form the desired polyester intermediate may be aliphatic, aromatic, or combinations thereof, having a total of 2 to 12 carbon atoms, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1, 1,4-butanediol is the preferred glycol, including 4-cyclohexanedimethanol, decamethylene glycol, dodecamethylene glycol, and the like.

Hydroxyl-terminated polyether intermediates are diols or polyols having a total of 2 to 15 carbon atoms reacted with an alkylene oxide having 2 to 6 carbon atoms, usually an ether containing ethylene oxide or propylene oxide or mixtures thereof Polyether polyols derived from alkyl diols or glycols are preferred. For example, a hydroxyl functional polyether can be prepared by first reacting propylene glycol with propylene oxide followed by subsequent reaction with ethylene oxide. Primary hydroxyl groups obtained from ethylene oxide are more reactive than secondary hydroxyl groups and are therefore preferred. Useful commercially available polyether polyols include poly (ethylene glycol) containing ethylene oxide reacted with ethylene glycol, poly (propylene glycol) containing propylene oxide reacted with propylene glycol, poly (propylene glycol) containing water reacted with tetrahydrofuran ( Tetramethyl glycol) (PTMEG). Polytetramethylene ether glycol (PTMEG) is a preferred polyether intermediate. The polyether polyol further comprises a polyamide adduct of alkylene oxide, such as an ethylenediamine adduct containing a reaction product of ethylenediamine and propylene oxide, a diethylenetriamine adduct containing a reaction product of diethylenetriamine and propylene oxide, and similar polyamides. A type of polyether polyol may be included. Copolyethers may also be utilized in the present invention. Conventional copolyethers include the reaction product of THF and ethylene oxide or THF and propylene oxide. These are available from BASF as poly THF B, a block copolymer, and poly THF R, a random copolymer. The various polyether intermediates generally have a number average molecular weight (M _n ) determined by terminal functional group assays, where M _n is greater than about 700, for example from about 700 to about 10,000, desirably An average molecular weight of about 1000 to about 5000, preferably about 1000 to about 2500. Certain desirable polyether intermediate is a blend of two or more different molecular weight of the polyether, for example, _{M n} is the PTMEG and _{M n} of 2000 is a blend of PTMEG 1000.

  The most preferred embodiment of the present invention uses a polyester intermediate made by reacting adipic acid with a 50/50 blend of 1,4-butanediol and 1,6-hexanediol.

The polycarbonate-based polyurethane resin of the present invention is prepared by reacting diisocyanate with a blend of hydroxyl-terminated polycarbonate and chain extender. Hydroxyl-terminated polycarbonate can be prepared by reacting glycol with carbonate.

  U.S. Pat. No. 4,131,731 discloses hydroxyl-terminated polycarbonates and methods for their preparation, which are hereby incorporated by reference. Such polycarbonates are linear and have terminal hydroxyl groups and are essentially free of other end groups. The essential reactants are glycol and carbonate. Suitable glycols include alicyclic and aliphatic diols containing 4 to 40, preferably 4 to 12 carbon atoms, and 2 to 20 alkoxy groups per molecule, each alkoxy group being from 2 to Selected from polyoxyalkylene glycols containing 4 carbon atoms. Diols suitable for use in the present invention are aliphatic diols containing 4 to 12 carbon atoms, such as 1,4-butanediol, 1,4-pentanediol, neopentyl glycol, 1,6-hexanediol. 2,2,4-trimethyl-1,6-hexanediol, 1,10-decanediol, hydrogenated dilinoleyl glycol, hydrogenated dioleyl glycol, and alicyclic diols such as 1,3-cyclohexanediol, 1,4-dimethylolcyclohexane, 1,4-cyclohexanediol, 1,3-dimethylolcyclohexane, 1,4-endomethylene-2-hydroxy-5-hydroxymethylcyclohexane, and polyalkylene glycol. The diol used in the above reaction may be a single diol or a mixture of diols depending on the properties desired in the final product.

  Polycarbonate intermediates that are hydroxyl terminated are generally known in the art and in the literature. Suitable carbonates are selected from alkylene carbonates composed of 5- to 7-membered rings having the general formula:

ここで、Ｒは、２から６個の直鎖炭素原子を含む飽和２価ラジカルである。本発明において用いるのに適しているカーボネートは、炭酸エチレン、炭酸トリメチレン、炭酸テトラメチレン、炭酸１，２−プロピレン、炭酸１，２−ブチレン、炭酸２，３−ブチレン、炭酸１，２−エチレン、炭酸１，３−ペンチレン、炭酸１，４−ペンチレン、炭酸２，３−ペンチレン、および炭酸２，４−ペンチレンを含む。

Here, R is a saturated divalent radical containing 2 to 6 straight-chain carbon atoms. Suitable carbonates for use in the present invention are ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-ethylene carbonate, 1,3-pentylene carbonate, 1,4-pentylene carbonate, 2,3-pentylene carbonate, and 2,4-pentylene carbonate.

  Dialkyl carbonates, alicyclic carbonates, and diaryl carbonates are also suitable in the present invention. The dialkyl carbonate may contain 2 to 5 carbon atoms in each alkyl group, specific examples of which are diethyl carbonate and dipropyl carbonate. Alicyclic carbonates, particularly dialicyclic carbonates, may contain 4 to 7 carbon atoms in each ring structure, and there may be one or two such structures. When one group is alicyclic, the other may be either alkyl or aryl. In contrast, if one group is aryl, the other may be alkyl or alicyclic. Preferred examples of diaryl carbonates that may contain 6 to 20 carbon atoms in each aryl group are diphenyl carbonate, ditolyl carbonate, and dinaphthyl carbonate.

  The reaction is carried out in the presence or absence of a transesterification catalyst from 10: 1 to 1:10 while removing low-boiling glycols by distillation at temperatures between 100 ° C. and 300 ° C. and pressures in the range of 0.1 to 300 mm Hg, but It is preferably carried out by reacting glycol with carbonate, preferably alkylene carbonate, in a molar range of 3: 1 to 1: 3.

More particularly, the hydroxyl terminated polycarbonate is prepared in two stages. In the first stage, glycol is reacted with alkylene carbonate to produce a low molecular weight hydroxyl terminated polycarbonate. Low boiling glycols are removed by distillation at 100 ° C. to 300 ° C., preferably 150 ° C. to 250 ° C. under reduced pressure of 10 to 30 mmHg, preferably 50 to 200 mmHg. A fractionation tower is used to separate the by-product glycol from the reaction mixture. By-product glycol is removed from the top of the column and unreacted alkylene carbonate and glycol reactants are returned to the reactor as reflux. An inert gas or inert solvent stream may be used to facilitate removal of by-product glycols when by-product glycols are produced. When the amount of by-product glycol obtained indicates that the degree of polymerization of the hydroxyl-terminated polycarbonate is in the range of 2 to 10, the pressure is gradually reduced from 0.1 to 10 mmHg, and unreacted glycol and alkylene carbonate Is removed. This represents the beginning of the second reaction stage, when glycol is produced in the second reaction stage at 100 ° C. to 300 ° C., preferably at 150 ° C. to 250 ° C. and pressures of 0.1 to 10 mmHg. At the same time, the low molecular weight hydroxyl-terminated polycarbonate is condensed until the desired molecular weight of the hydroxyl-terminated polycarbonate is reached by distilling off the glycol. The molecular weight (M _n ) of the hydroxyl-terminated polycarbonate can vary from about 500 to about 10,000, but in a preferred embodiment it ranges from 500 to 2500.

  The second necessary component to make the TPU polymer of the present invention is a polyisocyanate.

The polyisocyanates of the present invention generally have the formula R (NCO) _n , where n is generally 2 to 4 and 2 is highly preferred since the composition is a thermoplastic resin. Thus, polyisocyanates having 3 or 4 functional groups are very small, for example less than 5% by weight, preferably less than 2%, based on the total weight of all polyisocyanates, since they cause crosslinking. Used in R may be aromatic, alicyclic, and aliphatic, or combinations thereof, generally having a total of 2 to about 20 carbon atoms. Examples of suitable aromatic diisocyanates are diphenylmethane-4,4′-diisocyanate (MDI), H ₁₂ MDI, m-xylylene diisocyanate (XDI), m-tetramethylxylylene diisocyanate (TMXDI), phenylene-1,4. -Diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI), and diphenylmethane-3,3'-dimethoxy-4,4'-diisocyanate (TODI). Examples of suitable aliphatic diisocyanates are isophorone diisocyanate (IPDI), 1,4-cyclohexyl diisocyanate (CHDI), hexamethylene diisocyanate (HDI), 1,6-diisocyanato-2,2,4,4-tetramethylhexane ( TMDI), 1,10-decane diisocyanate, and trans-dicyclohexylmethane diisocyanate (HMDI). A highly preferred diisocyanate is MDI containing less than about 3% by weight of ortho-para (2,4) isomer.

A third necessary ingredient to make the TPU polymer of the present invention is a chain extender. Suitable chain extenders are lower aliphatic or short chain glycols having from about 2 to about 10 carbon atoms, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, triethylene glycol, cyclohexyl. Includes the cis-trans isomer of dimethylol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, 1,3-butanediol, and 1,5-pentanediol. Aromatic glycols may also be used as chain extenders and are a preferred option for high heat utilization. Benzene glycol (HQEE) and xylene glycol are suitable chain extenders used to make the TPU of the present invention. Xylene glycol is a mixture of 1,4-di (hydroxymethyl) benzene and 1,2-di (hydroxymethyl) benzene. Benzene glycol is a preferred aromatic chain extender, in particular bis (β-hydroxyethyl) ether, also known as hydroquinone, ie 1,4-di (2-hydroxyethoxy) benzene; resorcinol, ie 1 Bis (β-hydroxyethyl) ether also known as 1,3-di (2-hydroxyethyl) benzene; catechol, ie bis (β also known as 1,2-di (2-hydroxyethoxy) benzene -Hydroxyethyl) ether; and combinations thereof. A preferred chain extender is 1,4-butanediol.

The above three required components (hydroxyl terminated intermediate, polyisocyanate, and chain extender) are preferably reacted in the presence of a catalyst.

In general, any conventional catalyst may be utilized to react diisocyanates with hydroxyl-terminated intermediates or chain extenders, and the same is well known in the art and literature. Examples of suitable catalysts include various alkyl ethers or alkyl thiol ethers of bismuth or tin, where the alkyl moiety has 1 to about 20 carbon atoms, specific examples include bismuth octoate, bismuth Includes laurate and the like. Preferred catalysts include various tin catalysts such as stannous octoate, dibutyltin dioctoate, dibutyltin dilaurate, and the like. The amount of such catalyst is generally small, for example from about 20 to about 200 parts per million based on the total weight of the polyurethane-forming monomer.

  The TPU polymers of the present invention may be made by any of the conventional polymerization methods well known in the art and literature.

The thermoplastic polyurethanes of the present invention are preferably made by a “one-shot” process. In this process, all components are added together or substantially simultaneously to a heated extruder and react to produce a polyurethane. The equivalent ratio of diisocyanate to the total equivalent weight of hydroxyl-terminated intermediate and diol chain extender is generally from about 0.95 to about 1.10, desirably from about 0.97 to about 1.03, preferably about 0.97. To about 1.00. The resulting TPU should have a Shore A hardness of 65A to 95A, preferably about 75A to about 85A to achieve the most desirable properties of the finished article. Reaction temperatures utilizing urethane catalysts are generally from about 175 ° C to about 245 ° C, preferably from about 180 ° C to about 220 ° C. The molecular weight (Mw) of the thermoplastic polyurethane is generally about 100,000 to about 800,000, desirably about 150,000 to about 400,000, preferably about 150, as measured by GPC relative to polystyrene standards. From about 50,000 to about 350,000.

The thermoplastic polyurethane may be prepared utilizing a prepolymer process. In the prepolymer route, the hydroxyl-terminated intermediate is generally reacted with an excess equivalent of one or more polyisocyanates to form a prepolymer solution containing free or unreacted polyisocyanate in solution. The reaction is generally carried out in the presence of a suitable urethane catalyst at a temperature of about 80 ° C. to about 220 ° C., preferably about 150 ° C. to about 200 ° C. Subsequently, the above-described selective type of chain extender is added to the isocyanate end groups and in approximately equal equivalents to any free or unreacted diisocyanate compound. The overall equivalent ratio of the total diisocyanate to the total equivalents of hydroxyl-terminated intermediate and chain extender is thus about 0.95 to about 1.10, desirably about 0.98 to about 1.05, preferably about 0.99 to about 1.03. The equivalent ratio of hydroxyl terminated intermediate to chain extender is adjusted to provide a Shore hardness of 65A to 95A, preferably 75A to 85A. The chain extension reaction temperature is generally about 180 ° C to about 250 ° C, preferably about 200 ° C to about 240 ° C. Usually, the prepolymer route may be performed in any conventional apparatus, with an extruder being preferred. Thus, the hydroxyl-terminated intermediate is reacted with an excess equivalent amount of diisocyanate in the first part of the extruder to form a prepolymer solution, followed by the addition of a chain extender in the downstream part and reaction with the prepolymer solution. Let Any conventional extruder may be utilized, and an extruder with a barrier screw having a length to diameter ratio of at least 20, preferably at least 25 is utilized.

  Appropriate amounts of useful additives may be utilized, and useful additives include opacifying pigments, colorants, mineral fillers, stabilizers, lubricants, UV absorbers, processing aids, and as required. Other additives may be included. Useful opacifying pigments include titanium dioxide, zinc oxide, and titanate yellow, and useful color pigments include carbon black, yellow oxide, brown oxide, crude and burned Siena or amber, oxidation Includes chromium green, cadmium pigments, chromium pigments, and other mixed metal oxides and organic pigments. Useful fillers include diatomaceous earth (super floss) clay, silica, talc, mica, wollastonite, barium sulfate, and calcium carbonate. If desired, useful stabilizers, such as antioxidants, may be used, useful stabilizers may include phenolic antioxidants, useful light stabilizers include organophosphate esters, and organotin thiolates (mercaptides). )including. Useful lubricants include metal stearates, paraffin oil, and amide waxes. Useful UV absorbers include 2- (2'-hydroxyphenol) benzotriazole and 2-hydroxybenzophenone.

  Plasticizer additives can also be advantageously utilized to reduce hardness without affecting properties.

  During the melt spinning process, the TPU polymer may be lightly crosslinked with a crosslinking agent. The cross-linking agent is a hydroxyl-terminated intermediate prepolymer, which is a polyether, polyester, polycarbonate, polycaprolactone, or a mixture thereof reacted with a polyisocyanate. Polyesters or polyethers are the preferred hydroxyl-terminated intermediates that make up the crosslinker, with polyethers being most preferred when used in combination with polyester TPU. The prepolymer crosslinker has greater than about 1.0, preferably from about 1.0 to about 3.0, more preferably from about 1.8 to about 2.2 isocyanate functional groups. It is particularly preferred if both ends of the hydroxyl-terminated intermediate are capped with isocyanate and thus have 2.0 isocyanate functionality.

  The polyisocyanate used to make the crosslinker is the same as described above in making the TPU polymer. Diisocyanates such as MDI are preferred diisocyanates.

The crosslinking agent has a number average molecular weight (M _n ) of from about 1,000 to about 10,000 daltons, preferably from about 1,200 to about 4,000 daltons, more preferably from about 1,500 to about 2,800 daltons. Have. With a cross-linking agent having an _Mn greater than about 1500, better set characteristics can be obtained.

  The weight percent of the crosslinker used with the TPU polymer is from about 2.0% to about 20%, preferably from about 8.0% to about 15%, more preferably from about 10% to about 13%. The percentage of crosslinker used is weight percent based on the total weight of TPU polymer and crosslinker.

  A preferred melt spinning process for making the TPU fibers of the present invention involves feeding a preformed TPU polymer to the extruder to melt the TPU polymer, and the crosslinker is close to the stage where the TPU melt exits the extruder. Downstream or continuously after the TPU melt leaves the extruder. The cross-linking agent may be added to the extruder before the melt exits the extruder or may be added to the extruder after the melt exits the extruder. If the crosslinker is added after the melt exits the extruder, mix with the TPU melt using a static or dynamic mixer to ensure proper mixing of the crosslinker into the TPU polymer melt. Need to be done. After exiting the extruder, the molten TPU polymer and crosslinker flow into the manifold. The manifold divides the melt stream into separate streams, each of which is fed to a plurality of spinnerets. There is usually a melt pump for each separate flow that flows from the manifold, and each melt pump feeds several spinnerets. The spinneret has small holes and the melt is forced through the small holes and exits the spinneret in the form of monofilament fibers. The size of the hole in the spinneret depends on the desired size (denier) of the fiber.

  The TPU polymer melt may pass through the spin accumulation assembly and exit the used spin accumulation assembly as a fiber. The preferred spin accumulation assembly used is one that results in a plug flow of TPU polymer through the assembly. The most preferred spin accumulation assembly is that described in PCT patent application WO 2007/076380, which is incorporated herein in its entirety.

  As the fiber exits the spinneret, it is cooled before being wound on a spool. The fiber passes over the first godet, the finishing oil is applied, and the fiber proceeds to the second godet. An important aspect of the process of making the fiber of the present invention is the relative speed at which the fiber is wound on a spool. Relative speed means the speed of the melt exiting the spinneret (melt speed) in relation to the winding speed. In a normal prior art TPU melt spinning process, the fiber is wound at a speed 4 to 6 times the melt speed. This pulls or stretches the fiber. In the case of the intrinsic fibers of the present invention, this large tension is not preferred. In order to operate the process, the fiber must be wound at a speed at least equal to the melt speed. For the fibers of the present invention, the fiber must be wound at a speed that is faster than the melt speed but not greater than 50%, preferably not greater than 20%, more preferably not greater than 10% and not greater than 5%. Sometimes excellent results are obtained. Although it is believed that a take-up speed that is the same as the melt speed would be ideal, it is necessary to have a slightly higher take-up speed in order to operate the process. For example, fibers exiting the spinneret at a speed of 300 meters per minute would most preferably be wound at a speed between 300 and 315 meters per minute.

  The fibers of the present invention can be made with various deniers. Denier is a term in the art that specifies fiber size. Denier is a weight of 9000 meters fiber length in grams. The fibers of the present invention are usually made in sizes ranging from 20 to 600 denier, preferably from 40 to 400, more preferably from 70 to 360 denier.

  When fibers are made by the process of the present invention, after or during cooling, and immediately before being wound on a spool, an anti-tack additive (eg a finishing oil, for example silicone oil) is usually added to the fiber. Added to the surface.

  An important aspect of the melt spinning process is the mixing of the TPU polymer melt and the crosslinker. Proper uniform mixing is important to achieve uniform fiber properties and to achieve long uptime without fiber breakage. The mixing of the TPU melt and the crosslinker should be a way to achieve plug flow, ie first in first out. Appropriate mixing can be achieved with a dynamic mixer or a static mixer. Static mixers are harder to clean and therefore dynamic mixers are preferred. A dynamic mixer having a feed screw and a mixing pin is a preferred mixer. US Pat. No. 6,709,147, incorporated herein by reference, describes such a mixer and has a mixing pin that can be rotated. The mixing pin may be in place, for example attached to the body of the mixer and may extend towards the center line of the feed screw. The mixing feed screw may be attached by screw to the end of the extruder screw and the mixer housing may be bolted to the extruder. The feed screw of the dynamic mixer should be designed to progressively move the polymer melt, with little back mixing and to achieve a melt plug flow. The L / D of the mixing screw should be greater than 3 to less than 30, preferably from about 7 to about 20, and more preferably from about 10 to about 12.

  The temperature in the mixing zone where the TPU polymer melt is mixed with the crosslinking agent is from about 200 ° C to about 240 ° C, preferably from about 210 ° C to about 225 ° C. These temperatures are necessary to react the polymer without degrading it.

  The TPU formed is reacted with a crosslinker during the melt spinning process to about 200,000 to about 800,000, preferably about 250,000 to about 500,000, more preferably about 300,000 to about 450.000. The molecular weight (Mw) of the final fiber form of TPU is obtained.

  The spinning temperature (the temperature of the polymer melt in the spinneret) should be above the melting point of the polymer, preferably about 10 ° C. to about 20 ° C. above the melting point of the polymer. The higher the spinning temperature that can be used, the better the spinning. However, if the spinning temperature is too high, the polymer can degrade. Thus, temperatures from about 10 ° C. to about 20 ° C. above the melting point of the TPU polymer are optimal to achieve a good spinning balance without polymer degradation. If the spinning temperature is too low, the polymer may solidify in the spinneret and cause fiber breakage.

  The inherent fibers of the present invention have a relatively flat and / or constant modulus in loading and unloading cycles between 100% and 200% elongation. This flat modulus is less than 0.023 gram weight per denier at 100% elongation and less than 0.036 gram weight per denier at 150% elongation when all data is collected from 360 denier fibers. 200% elongation, less than 0.053 gram weight per denier, 200% elongation, less than 0.027 gram weight per denier, 150% elongation, 0. Also evidenced by stress of less than 018 gram weight and less than 0.015 gram weight per denier at 100% elongation.

  This flat modulus is less than 0.158 gram per denier at 100% elongation and less than 0.207 gram per denier at 150% elongation when all data is collected from 70 denier fibers. , Also demonstrated by stress less than 0.265 gram weight per denier at 200% elongation, less than 0.021 gram weight per denier at 200% elongation during unloading cycle, 0 per denier at 150% elongation It is also evidenced by a stress of less than 0.012 gram weight and less than 0.008 gram weight per denier at 100% elongation.

  The standard test procedure used to obtain the above modulus values was developed for elastic yarns by DuPont. This test subjects the fiber to a series of five cycles. In each cycle, the fiber is drawn to 300% elongation and relaxed (between the original gauge length and 300% elongation) using a constant elongation rate. The strain% (% set) is measured after the fifth cycle. Next, a fiber sample is taken through the sixth cycle and stretched until it breaks. The apparatus records the load at each elongation, the maximum load before break, and the break load, and the elongation at break and elongation at the maximum load, in units of grams per denier. This test is usually performed at room temperature (23 ° C. ± 2 ° C. and 50% ± 5% humidity).

  The fibers of the present invention have an elongation at break of at least 400%, preferably about 450 to 500%. This fiber is a monofilament having a round shape. Referring to FIG. 2, it can be seen that 70 denier monofilament fibers are substantially round in cross-sectional shape. FIG. 1 shows a 70 denier monofilament dry-spun fiber having a larger cross-sectional width.

  FIG. 3 shows a graph comparing dry spun fibers to the melt spun fibers of the present invention. This graph plots denier (X-axis) and fiber width squared (square micron). This graph shows that the melt-spun fiber of the present invention has a constant slope on the graph, whereas the dry-spun fiber has an exponentially increasing slope. The result is that the fibers of the present invention can be used to make fabrics that are thinner and therefore more comfortable for the wearer.

  Another important feature of the fiber of the present invention is that it exhibits improved fabric burst strength compared to dry-spun fibers.

  This feature can be demonstrated by performing a Ball Burst Puncture Strength Test according to ASTM D751 using a 1 inch diameter sphere. This test simulates a finger passing through a cloth to form a hole. It was very surprising that the fibers of the present invention show an improvement in burst strength of about 50 to 75% compared to dry-spun polyurethane fibers. This improved burst strength exists despite the fact that the tensile strength of the fibers is almost the same.

  The fibers of the present invention also have a higher heat capacity. The combination of a flat modulus curve, higher heat capacity, and thinner gauge has produced a fabric made of the fibers of the present invention that makes the garment wearer feel comfortable.

  Fabrics made using the fibers of the present invention may be made by knitting or weaving. In many cases, it is preferred to make the fabric using other fibers together with TPU fibers. It is particularly preferred to use hard fibers together with the elastic fibers of the present invention. Hard fibers such as nylon and / or polyester are preferred. Hard fibers improve the tear resistance of the fabric over 100% elastic fiber fabric. Preferred fabrics are knitted with alternating fibers, for example knitted with 140 denier TPU / 70 denier nylon yarns alternating with 140 denier TPU yarns (referred to as 1-1 fabrics), or It is knitted using 140 denier TPU / 70 denier nylon yarn followed by two 140 denier TPU yarns (referred to as 1-2 fabric).

  Clothing can be made with the fabric of the present invention. The most preferred use of the fabric is to make undergarments or garments that fit snugly due to the comfort provided by the fibers. Underwear, such as bras and T-shirts, and sports garments used for activities such as running, skiing, cycling, or other sports can take advantage of the properties of these fibers. Garments worn in contact with the body enjoy the advantage of the flat modulus of these fibers, as the modulus becomes even lower when the fibers reach body temperature. A garment that feels snug increases comfort about 30 seconds to 5 minutes after the fibers reach body temperature. It will be appreciated by those skilled in the art that any garment can be made from the fabrics and fibers of the present invention. Exemplary embodiments are bra shoulder straps made from woven fabric and bra belts made from knitted fabric, both woven and knitted fabrics of the present invention. Contains melt spun TPU fibers. Because the fabric is elastic, the bra straps will not require adjustable fasteners.

  A better understanding of the present invention will be gained by reference to the following examples.

The TPU polymer used in the examples was made by reacting a polyester hydroxyl terminated intermediate (polyol) with 1,4-butanediol chain extender and MDI. The polyester polyol was made by reacting adipic acid with a 50/50 mixture of 1,4-butanediol and 1,6-hexanediol. The polyol had a _Mn of 2500. The TPU was created by a one-shot process. Crosslinking agent added to the TPU during spinning process, M _n was a polyether prepolymer made by creating an end-capped polyether PTMEG 1000 with an isocyanate is reacted with MDI. The crosslinker was used at a level of 10% by weight of the total weight of TPU and crosslinker. The fibers were melt spun to make 40, 70, 140 and 360 denier fibers used in the examples.

  This example shows a relatively flat modulus curve for the inventive fiber (70 denier) compared to existing prior art melt spun TPU fiber (40 denier) and commercial dry spun fiber (70 denier). Presented for.

  The test procedure used was the test procedure described above for testing the elastic properties. An Instron Model 5564 tensiometer was used with a Merlin Software. The test conditions were 23 ° C. ± 2 ° C. and humidity 50% ± 5%. The fiber length of the test sample was 50.0 mm. Four samples were tested and the result is the average of the four samples tested. The results are shown in Table I.

上記のデータのすべては、試験された４つの試料についての平均値である。

All of the above data are average values for the four samples tested.

  From the above data, it can be seen that the melt spun fiber of the present invention has a relatively flat modulus curve during the fifth test cycle. The first cycle is usually ignored because it releases the stress in the fiber.

  This example is presented to show the width of the melt spun fibers of the present invention compared to commercially available dry spun fibers. The width was determined by SEM. The results are shown in Table II.

分かるように、乾式紡糸繊維の方がはるかに高い幅を有し、デニールが増加するほど差が大きくなる。

As can be seen, dry spun fibers have a much higher width, with the difference increasing as denier increases.

  This example is presented to show the improved burst strength of the melt spun TPU fibers of the present invention compared to commercially available dry-spun polyurethane fibers. 70 denier fibers were used to prepare signel jersey fabric from each type of fiber. The fabric was tested for burst puncture strength according to ASTM D751. The results are shown in Table III. The result is the average of 5 samples tested.

本発明の溶融紡糸繊維は乾式紡糸繊維より高い引張強さを有しなかったにもかかわらず、溶融紡糸繊維の破裂強度がより高かったことは非常に驚くべきことであった。

It was very surprising that the melt spun fibers of the present invention had a higher burst strength, even though they did not have a higher tensile strength than the dry spun fibers.

  Although the best mode and preferred embodiments have been shown in accordance with patent statutes, the scope of the invention is not limited thereto but rather is limited by the scope of the appended claims.

Claims (19)

A melt-spun elastic fiber made from a cross-linked thermoplastic polyurethane, the fiber having a critical elongation of at least 400%;
The melt spun elastic fiber is in a duty cycle
(I) Less than 0.226 mN (0.023 gram weight) per denier at 100% elongation,
(Ii) less than 0.353 mN (0.036 gram weight) per denier at 150% elongation;
(Iii) Less than 0.520 mN (0.053 gram weight) per denier at 200% elongation
Shows the stress value of
The melt spun elastic fiber is used in an unloading cycle.
(I) less than 0.265 mN (0.027 gram weight) per denier at 200% elongation;
(Ii) less than 0.177 mN (0.018 gram weight) per denier at 150% elongation;
(Iii) Less than 0.147 mN (0.015 gram weight) per denier at 100% elongation
Shows the stress value of
The thermoplastic polyurethane is
(A) a linear hydroxyl-terminated polyester having a number average molecular weight of 500 to 10,000;
(B) a polyisocyanate;
(C) a glycol chain extender having from 2 to 10 carbon atoms;
A fiber prepared from a mixture comprising:   The fiber of claim 1 wherein the 40 denier monofilament fiber has a width of less than 100 microns. Is the fiber fabric having a denier of 70, when the fabric is tested for puncture strength according to ASTM D751, the fabric has a greater elongation at loads than 2.72 kg (6 lbs), according to claim 1 fiber. The fiber according to claim 1 , wherein the fiber is crosslinked with a polyether crosslinking agent. The fiber of claim 1 , wherein the polyester thermoplastic polyurethane has a weight average molecular weight of 200,000 to 700,000 daltons. 5. The fiber of claim 4 , wherein the crosslinker is 5 to 20 weight percent of the total weight of the polyester thermoplastic polyurethane and the crosslinker. The fiber of claim 6 , wherein the cross-linking agent is 8 to 12 weight percent of the total weight of the polyester thermoplastic polyurethane and the cross-linking agent. A fabric comprising the fiber according to claim 1. The fabric of claim 8, further comprising fibers comprising nylon and / or polyester. Wherein the fabric is composed of two yarns of one yarn per thermoplastic polyurethane fibers of the fiber, fabric of claim 9. 10. The fabric of claim 9 , wherein the thermoplastic polyurethane fiber has a denier of 20 to 600. 12. The fabric of claim 11 , wherein the thermoplastic polyurethane fiber has a denier of 70 to 360. Before SL fibers have a denier of 7 0, the thermoplastic polyurethane fibers have a denier of 1 40, fabric of claim 8. An article for clothing comprising the cloth according to claim 9 . The articles are underwear, goods products for clothing according to claim 14. It said article is a brassiere, goods products for clothing according to claim 15. A process for producing the elastic fiber according to claim 1 , comprising:
(A) winding step melt spinning a thermoplastic polyurethane through a spinneret, and (b) the elastic fibers in該紡clue not faster than 50% compared to Ru out polymer melt rate from gold winding speed winding A process that includes steps. The process of claim 17 , wherein the winding speed is not faster than 20% compared to the polymer melt speed exiting the spinneret. The process of claim 18 , wherein the winding speed is not faster than 10% compared to the polymer melt rate exiting the spinneret.

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