Patent Description:
Conventionally, pile fabrics (also referred to as "napped fabrics") of artificial furs have been required to have texture and a gloss like those of natural furs. Polyester-based fibers have excellent firmness and low cold setting properties, and thus the use of polyester-based fibers in a pile fabric is being looked into. The term "cold setting" refers to the fixation of the shape of a pile fabric in a deformed state at room temperature in, e.g., storage in the deformed state. When a pile fabric is compressed and packed in, e.g., transportation, the shape of the pile fabric in packing is fixed, and its texture before packing may be hardly restored. Thus, there is a demand for low cold setting properties. Since polyester-based fibers have excellent, low cold setting properties, the polyester-based fibers are less likely to be severely disturbed even when compressed and packed. Thus, marketability of pile fabrics is less likely to be significantly compromised. However, although a pile fabric in which polyester-based fibers are used is excellent in voluminousness and compression recoverability, the polyester-based fibers are insufficiently polished at a temperature at which modacrylic fibers usually used are polished in the production of the pile fabric. Thus, crimps on the polyester-based fibers are not sufficiently removed. Thus, the pile fibers are entangled with each other, which results in a rough feel and a hair split. Consequently, the pile fabric has a feel and an appearance different from those of natural fur.

Thus, Patent Document <NUM> proposes to improve the crimp removability of polyester-based fibers by adjusting, e.g., a fiber cross-section, fineness, fiber length, crimp frequency, percentage of crimp, and crimp fastness. Patent Document <NUM> proposes to improve the crimp removability of polyester-based fibers in polishing by crimping the polyester-based fibers after the polyester-based fibers are subjected to heat treatment at <NUM> to <NUM> under conditions in which shrinkage is limited to <NUM>% to <NUM>% in spinning. Patent Document <NUM> discloses a pile cloth with level differences having long pile parts and short pile parts. Patent Document <NUM> discloses a pile fabric used for artificial fur, stuffed animals, rugs and the like. Patent Document <NUM> discloses a high-and-low piles-revealing cut pile fabric having rugged surface with snarled piles. Patent Document <NUM> discloses thermal fabric articles.

However, a pile fabric in which polyester-based fibers are used still needs to be subjected to polishing at a high temperature close to <NUM>, and has a problem of the improvement of crimp removability.

Moreover, since a long pile portion in the pile fabric comes into contact with the human skin, as many crimps as possible need to be removed in the long pile portion so that a good hand feeling is provided. On the other hand, since a short pile portion in the pile fabric provides voluminousness in the entire pile fabric, crimps need to be appropriately left in the short pile portion while the short pile portion has crimp removability. Nonetheless, a pile fabric that has excellent crimp removability while ensuring voluminousness and compression recoverability has not been known at present. Thus, conventional pile fabrics still have room for improvement.

In order to solve the above conventional problem, the present invention provides a pile fabric that includes a long pile portion and a short pile portion, has a good appearance, and good voluminousness and compression recoverability, and further has excellent crimp removability. The present invention also provides a method for manufacturing the pile fabric.

One or more embodiments of the present invention relate to a pile fabric described below. The pile fabric includes a pile portion. The pile portion includes a long pile portion and a short pile portion. An average pile length of the long pile portion differs from an average pile length of the short pile portion by <NUM> or more. The long pile portion contains crimped polyester-based fibers in an amount of <NUM>% by weight or more. The short pile portion contains crimped polyester-based fibers in an amount of <NUM>% by weight or more. A crimp removal temperature of the crimped polyester-based fibers of the long pile portion is lower than a crimp removal temperature of the crimped polyester-based fibers of the short pile portion. The crimp removal temperature of the crimped polyester-based fibers of the short pile portion is <NUM> or more and <NUM> or less. Each of the crimp removal temperatures indicates a minimum temperature that satisfies the following numerical formula (<NUM>): <MAT> where, in the formula (<NUM>),.

One or more embodiments of the present invention also relate to a method for manufacturing the pile fabric that includes polishing at a temperature of <NUM> or more and <NUM> or less.

The present invention and the manufacturing method of the present invention can provide a pile fabric that includes a long pile portion and a short pile portion, has a good appearance, and good voluminousness and compression recoverability, and further has excellent crimp removability.

[<FIG> is a view illustrating criteria for evaluating the appearance of a pile fabric.

The present inventors conducted intensive studies to solve the above problem. As a result of this, the inventors found that a pile fabric with an excellent feel and excellent voluminousness and compression recoverability can be obtained by using, in a pile fabric that includes a long pile portion and a short pile portion, polyester-based fibers as main components of fibers constituting the long pile portion and fibers constituting the short pile portion, and appropriately adjusting the crimp removability of the polyester-based fibers.

In one or more embodiments of the present invention, the term "polyester-based fibers" refers to polyester-based fibers both of the long pile portion and of the short pile portion. The term "polyester-based fibers of the long pile portion" and the term "polyester-based fibers of the short pile portion" refer to the polyester-based fibers of the long pile portion and the polyester-based fibers of the short pile portion, respectively.

The long pile portion in the pile fabric contains crimped polyester-based fibers in an amount of <NUM>% by weight or more. The short pile portion in the pile fabric contains crimped polyester-based fibers in an amount of <NUM>% by weight or more. In the present invention, a pile portion is a napped portion of the pile fabric other than a base fabric (also referred to as a "ground structure") portion. From the viewpoints of the voluminousness and compression recoverability, the long pile portion contains the crimped polyester-based fibers in an amount of <NUM>% by weight or more, preferably in an amount of <NUM>% by weight or more, and more preferably in an amount of <NUM>% by weight or more of the total weight of the long pile portion, and the short pile portion contains the crimped polyester-based fibers in an amount of <NUM>% by weight or more, preferably in an amount of <NUM>% by weight or more, and more preferably in an amount of <NUM>% by weight or more of the total weight of the short pile portion. Hereinafter, fibers constituting the pile portion are also referred to as "pile fibers".

The pile fabric includes the long pile portion and the short pile portion having different pile lengths. The average pile length of the long pile portion differs from the average pile length of the short pile portion by <NUM> or more. Thus, it is possible to achieve a two-layer structure closely resembling natural fur. In the pile fabric, the average pile length of the long pile portion differs from that of the short pile portion preferably by <NUM> or more and <NUM> or less.

The pile fabric may further include a medium pile portion as well as the long pile portion and the short pile portion. The pile fabric can have an appearance closer to that of natural far by including the medium pile portion. Also, according to the invention, the average pile length of the long pile portion differs from that of the short pile portion by <NUM> or more. However, in order for the pile fabric to obtain a clearer appearance of a two-layer structure, the average pile length of the long pile portion differs from that of the short pile portion preferably by <NUM> or more and <NUM> or less, and more preferably by <NUM> or more and <NUM> or less.

According to the present invention, the medium pile portion also contains polyester-based fibers in an amount of <NUM>% by weight or more, more preferably in an amount of <NUM>% by weight or more, and further preferably in an amount of <NUM>% by weight or more of the total weight of the medium pile portion.

The average pile length is determined by vertically standing the fibers constituting each pile portion of the pile fabric such that the fibers are aligned, measuring the lengths from the roots of the fibers constituting each pile portion of the pile fabric (roots on the front surface side of the pile fabric) to the tip of each pile portion at <NUM> sections in each pile portion, and averaging the measured lengths.

In one or more embodiments of the present invention, when a plurality of pile portions having different pile lengths are present, a pile portion having the longest average pile length is referred to as a "long pile portion", and a pile portion having the shortest average pile length is referred to as a "short pile portion". Here, the phrase "pile portions having different pile lengths" means that the average pile lengths of the respective pile portions differ from each other by <NUM> or more.

The pile portion may contain other fibers, e.g., modacrylic fibers and vinyl chloride-based fibers, as well as the polyester-based fibers.

From the viewpoint of being able to obtain soft texture, the long pile portion preferably contains modacrylic fibers constituted by an acrylic-based copolymer containing acrylonitrile in an amount of <NUM>% by weight or more and less than <NUM>% by weight. It is possible to provide a pile fabric with good texture, recovering strength, and voluminousness by using the polyester-based fibers and the modacrylic fibers in combination.

In one or more embodiments of the present invention, the long pile portion may contain. the polyester-based fibers in an amount of <NUM>% by weight or more and <NUM>% by weight or less and the modacrylic fibers in an amount of <NUM>% by weight or less. The long pile portion may contain the polyester-based fibers in an amount of <NUM>% by weight or more and <NUM>% by weight or less and the modacrylic fibers in an amount of <NUM>% by weight or less. The long pile portion may contain the polyester-based fibers in an amount of <NUM>% by weight or more and <NUM>% by weight or less and the modacrylic fibers in an amount of <NUM>% by weight or less.

The acrylic-based copolymer preferably contains another monomer that is copolymerizable with acrylonitrile in an amount of more than <NUM>% by weight and <NUM>% by weight or less as well as acrylonitrile. The other monomer is not particularly limited, but is preferably at least one monomer selected from the group consisting of vinyl halides, vinylidene halides, and metal salts of sulfonic acid-containing monomers, and more preferably at least one monomer selected from the group consisting of vinyl chloride, vinylidene chloride, and sodium styrenesulfonate, for example.

In one or more embodiments of the present invention, the pile fabric can be produced in the same manner as usual pile fabrics except that polishing is performed at a temperature of <NUM> or more and <NUM> or less. For example, a sliver constituted by pile fibers is knitted into a pile fabric (which may be referred to as a "knitted fabric") by a sliver knitting machine, and pre-polishing is performed at a temperature of <NUM> or more and <NUM> or less, and then polishing is performed at a temperature of <NUM> or more and <NUM> or less so that crimps are removed. Polishing may be performed multiple times at different temperatures. Moreover, a back surface (opposite side of the napped portion) of the pile fabric may be coated with a backing resin before polishing in order to eliminate or reduce pile fiber loss and for tentering. The backing resin may be an acrylic acid ester-based adhesive or polyurethane-based adhesive. Further, pre-shearing and shearing may be performed as needed.

A polyester-based resin constituting the polyester-based fibers may be, e.g., polyalkylene terephthalate, a copolyester containing polyalkylene terephthalate as the main component, or a combination thereof, but is not particularly limited thereto. Examples of the polyalkylene terephthalate include, but are not particularly limited to, polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate. In particular, from the viewpoint of heat characteristics, polyethylene terephthalate is preferred. Examples of the copolyester containing polyalkylene terephthalate as the main component include, but are not particularly limited to, copolyesters containing polyalkylene terephthalate such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, or polytrimethylene terephthalate as the main component and containing other copolymer components. In particular, the copolyester containing polyethylene terephthalate as the main component is preferred because of its relatively high decomposition temperature (Tg) and excellent handleability. In the present invention, the term "main component" refers to a component contained in an amount of <NUM> mol% or more, and the term "copolyester containing polyalkylene terephthalate as the main component" refers to a copolyester containing polyalkylene terephthalate in an amount of <NUM> mol% or more. The copolyester containing polyalkylene terephthalate as the main component contains polyalkylene terephthalate preferably in an amount of <NUM> mol% or more, more preferably in an amount of <NUM> mol% or more, and further preferably in an amount of <NUM> mol% or more.

Examples of the other copolymer components include the following: polycarboxylic acids such as isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, trimellitic acid, pyromellitic acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedioic acid, and their derivatives; dicarboxylic acids including a sulfonic acid salt such as <NUM>-sodiumsulfoisophthalic acid and dihydroxyethyl <NUM>-sodiumsulfoisophthalate, and their derivatives; and <NUM>,<NUM>-propanediol, <NUM>,<NUM>-propanediol, <NUM>,<NUM>-butanediol, <NUM>,<NUM>-hexanediol, neopentyl glycol, <NUM>,<NUM>-cyclohexanedimethanol, diethylene glycol, polyethylene glycol, trimethylolpropane, pentaerythritol, <NUM>-hydroxybenzoic acid, ε-caprolactone, and ethylene glycol ether of bisphenol A. These other copolymer components may be used alone or in combination of two or more.

Specific examples of the copolyester containing polyalkylene terephthalate as the main component include polyesters obtained through copolymerization of polyethylene terephthalate as the main component with at least one compound selected from the group consisting of ethylene glycol ether of bisphenol A, <NUM>,<NUM>-cyclohexanedimethanol, isophthalic acid, and dihydroxyethyl <NUM>-sodiumsulfoisophthalate.

The polyalkylene terephthalates and the copolyesters containing polyalkylene terephthalate as the main component may be used alone or in combination of two or more. In particular, it is preferable that the following are used alone or in combination of two or more: polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, a polyester obtained through copolymerization of polyethylene terephthalate as the main component with ethylene glycol ether of bisphenol A, a polyester obtained through copolymerization of polyethylene terephthalate as the main component with <NUM>,<NUM>-cyclohexanedimethanol, a polyester obtained through copolymerization of polyethylene terephthalate as the main component with isophthalic acid, and a polyester obtained through copolymerization of polyethylene terephthalate as the main component with dihydroxyethyl <NUM>-sodiumsulfoisophthalate.

The intrinsic viscosity (IV value) of the polyester-based resin is, although not particularly limited, preferably <NUM> or more and <NUM> or less, and more preferably <NUM> or more and <NUM> or less. When the intrinsic viscosity thereof is <NUM> or more, the mechanical strength of fibers obtained does not decrease. Moreover, when the intrinsic viscosity is <NUM> or less, the molecular weight is not too large, and the melt viscosity is not too high. Thus, it is easy to perform melt spinning, and the fineness of the fibers obtained is likely to be uniform.

For example, an additive agent such as a delustering agent, a lubricant, an antioxidant, a color pigment, a stabilizing agent, a flame retardant, or a toughening agent may be added to the polyester-based resin constituting the polyester-based fibers as needed. The delustering agent may be, e.g., titanium dioxide. Examples of the lubricant include silica microparticles and alumina microparticles.

The cross-sectional shape of the polyester-based fibers is not particularly limited. Examples of the cross-sectional shape include a circular shape and a modified shape. Examples of the modified shape include a Y shape and a flat shape. Examples of the flat shape include an oval shape, a rectangle, a flat multilobed shape, and a flat constriction shape. Examples of the flat constriction shape include shapes having circles or ovals linearly aligned such as a cocoon shape, a four skewered-dumpling shape, and a five skewered-dumpling shape.

From the viewpoint of increasing the voluminousness of the pile fabric, the polyester-based fibers preferably have a flat shape in which a length (b) of a long side of a fiber cross-section is larger than a length (a) of a short side of the fiber cross-section, and the length (b) of a long side of a fiber cross-section is more preferably not less than two times the length (a) of a short side of the fiber cross-section. From the viewpoint of increasing the voluminousness of the pile fabric, the length (b) of a long side of a fiber cross-section of the polyester-based fibers is, although not particularly limited, preferably not more than eight times, and more preferably not more than six times the length (a) of a short side of the fiber cross-section, for example. The term "long side of a fiber cross-section" refers to a line segment having the maximum length of a fiber cross-section, that is, a line segment having the maximum length, out of straight lines connecting any two points on an outer circumference of the fiber cross-section. The term "short side of the fiber cross-section" refers to a line segment having the maximum width of the fiber cross-section, that is, a line segment having the maximum length, out of straight lines that connect any two points on the outer circumference of the fiber cross-section which are perpendicular to the long side of the fiber cross-section. In the case of a circular shape, the length (b) of the long side of a fiber cross-section is the same as the length (a) of the short side of the fiber cross-section.

The polyester-based fibers have a crimp(s). The term "crimp" refers to a crimp imparted by a known crimp imparting method such as a gear crimping method or a stuffing box method, but is not particularly limited thereto. The crimp frequency of the polyester-based fibers is not particularly limited. From the viewpoints of bulkiness and processability in a carding machine, the crimp frequency is preferably <NUM> crimps/<NUM> or more and <NUM> crimps/<NUM> or less, and more preferably <NUM> crimps/<NUM> or more and <NUM> crimps/<NUM> or less, for example. In one or more embodiments of the present invention, the crimp frequency is measured in accordance with JIS L-<NUM>.

Examples of the form of the crimped polyester-based fibers include, although not particularly limited, a filament form, a staple form, and a tow form in which filaments are bundled together.

The polyester-based fibers of the short pile portion have a crimp removal temperature of <NUM> or more and <NUM> or less. Here, the term "crimp removal temperature" refers to the minimum temperature that satisfies the following numerical formula (<NUM>): <MAT> where, in the formula (<NUM>), A represents the length of a fiber bundle of the polyester-based fibers under a load of <NUM>/dtex after the fiber bundle is subjected to dry heat treatment at a predetermined temperature for <NUM> seconds under a load of <NUM>/dtex, and B represents the length of the fiber bundle under no load after the dry heat treatment is performed as above.

Specifically, the following will describe how the crimp removal temperature of the polyester-based fibers is measured. First, the polyester-based fibers are bundled to prepare a fiber bundle with <NUM> dtex. Both ends of the fiber bundle are trimmed such that the resulting sample has a length of about <NUM>. The sample is suspended vertically in a hot-air convection dryer. A <NUM>-weight is suspended from a lower end of the fiber bundle (a load of <NUM>/dtex is applied to the fiber bundle). In this state, the sample is subjected to heat treatment for <NUM> seconds at a predetermined temperature starting from <NUM> and increasing in increments of <NUM>. After each instance of heat treatment, a length A of the fiber bundle under a load of <NUM>/dtex, and a length B of the fiber bundle under no load after the weight has been removed are measured. The measurement thereof is performed five times at each temperature. The differences between the values of A and B are divided by A, and the values thus obtained are averaged. Out of the temperatures, the minimum temperature at which the average is less than <NUM>% is referred to as the "crimp removal temperature". That is, the crimp removal temperature indicates the minimum temperature that satisfies the numerical formula (<NUM>).

As above, the crimp removal temperature of the polyester-based fibers of the short pile portion is <NUM> or more and <NUM> or less. Thus, crimps are removed moderately from the polyester-based fibers of the short pile portion in a relatively low temperature range of <NUM> or more and <NUM> or less in polishing that is a step in pile fabric processing. Specifically, only crimps on a napped surface layer portion of the pile fabric are likely to be removed. Thus, it is possible to obtain a pile fabric having a good appearance and excellent voluminousness. If the crimp removal temperature of the polyester-based fibers of the short pile portion exceeds <NUM>, crimps are not sufficiently removed in polishing at a low temperature of <NUM> or more and <NUM> or less, and crimps on the pile fibers are hardly removed, resulting in a pile fabric having a poor appearance and feel. On the other hand, if the crimp removal temperature is lower than <NUM>, crimps on the pile fibers are almost completely removed in polishing at a low temperature of <NUM> or more and <NUM> or less, resulting in a pile fabric with inferior voluminousness.

When a pressure resistant vessel is filled with the polyester-based fibers of the short pile portion together with pure water while a pressure of <NUM> kPa or more and <NUM> kPa or less is applied, and hot-water treatment is performed at <NUM> for <NUM> minutes, the crimp removal temperature of the polyester-based fibers after the hot-water treatment is preferably <NUM> or more and <NUM> or less. When the crimp removal temperature of the polyester-based fibers is also <NUM> or more and <NUM> or less even after the hot-water treatment, crimps are removed moderately in polishing at a low temperature of <NUM> or more and <NUM> or less even through a step such as dyeing under hot-water conditions. Specifically, only the crimps on the napped surface layer portion of the pile fabric are likely to be removed. Thus, it is possible to obtain a pile fabric having a good appearance and excellent voluminousness.

The single fiber fineness of the polyester-based fibers of the short pile portion is, although not particularly limited, preferably <NUM> dtex or less, more preferably <NUM> dtex or less, further preferably <NUM> dtex or less, and particularly preferably <NUM> dtex or less, for example. If the single fiber fineness exceeds <NUM> dtex, heat is not sufficiently transferred in polishing, and the number of instances of polishing may need to be increased to moderately remove crimps. Moreover, an increase in the number of instances of polishing may deteriorate soft texture. Furthermore, from the viewpoint of fiber handleability, the single fiber fineness of the polyester-based fibers of the short pile portion is, although not particularly limited, preferably <NUM> dtex or more. When the short pile portion contains other fibers as well as the polyester-based fibers, from the viewpoints of the texture and crimp removability, the single fiber fineness of the other fibers is also preferably <NUM> dtex or less, more preferably <NUM> dtex or less, further preferably <NUM> dtex or less, and particularly preferably <NUM> dtex or less. Moreover, from the viewpoint of fiber handleability, the single fiber fineness of the other fibers is also preferably <NUM> dtex or more.

The polyester-based fibers of the short pile portion can be produced in the same manner as usual polyester-based fibers except that no heat treatment is performed on drawn yarns before crimping, after crimping, or before and after crimping; heat treatment is performed on drawn yarns at a temperature of <NUM> or more and <NUM> or less before crimping, after crimping, or before and after crimping; or heat treatment is performed on drawn yarns at a temperature of <NUM> or more and <NUM> or less before crimping, and heat treatment is performed on the drawn yarns at a temperature of <NUM> or more and <NUM> or less after crimping.

The phrase "before crimping" refers to a time period starting from the completion of drawing polyester-based fibers to the start of crimping. The phrase "after crimping" refers to a time period starting from the completion of crimping until crimped polyester-based fibers are finally obtained. When heat treatment is performed on drawn yarns at <NUM> after crimping, heat treatment at <NUM> is performed in a time period starting from the completion of crimping until crimped polyester-based fibers are finally obtained, for example. Before and after crimping, it is possible to include a step other than the heat treatment, such as oil applying, constant length cutting, or rewinding, for example.

Crystallization of the polyester-based fibers is not facilitated before crimping, after crimping, or before and after crimping by performing no heat treatment on drawn yarns before crimping, after crimping, or before and after crimping; or by performing heat treatment on drawn yarns at a temperature of <NUM> or more and <NUM> or less before crimping, after crimping, or before and after crimping. Therefore, it is possible to obtain polyester-based fibers having a crimp removal temperature of <NUM> or more and <NUM> or less. Moreover, as described above, since these polyester-based fibers are used for the short pile portion of the pile fabric, crimps are moderately removed from the polyester-based fibers in polishing at a low temperature of <NUM> or more and <NUM> or less in the pile fabric processing. Specifically, only the crimps on the napped surface layer portion of the pile fabric are likely to be removed. Thus, it is possible to obtain a pile fabric having a good appearance and excellent voluminousness.

From the viewpoint of reducing the shrinkage percentage of the polyester-based fibers, heat treatment is performed on drawn yarns preferably at a temperature of <NUM> or more and <NUM> or less, more preferably at a temperature of <NUM> or more and <NUM> or less, and further preferably at a temperature of <NUM> or more and <NUM> or less after crimping when no heat treatment is performed before crimping. The heat treatment time may be, e.g., <NUM> minutes or more and <NUM> minutes or less, but is not particularly limited thereto. Specifically, heat treatment after crimping is performed preferably at a temperature of <NUM> or more and <NUM> or less for <NUM> minutes or more and <NUM> minutes or less, and more preferably at a temperature of <NUM> or more and <NUM> or less for <NUM> minutes or more and <NUM> minutes or less. In the case where heat treatment is performed on drawn yarns only after crimping, crimps imparted to the polyester-based fibers may be tightly fixed thereto if the temperature of the heat treatment exceeds <NUM>. In this case, there is a possibility that the crimp removal temperature of the polyester-based fibers exceeds <NUM>. When the heat treatment time is <NUM> minutes or less, the productivity and production processability will be improved.

On the other hand, when heat treatment is performed on drawn yarns before and after crimping, heat treatment may be performed on the drawn yarns at a temperature of <NUM> or more and <NUM> or less before crimping, and heat treatment may also be performed on the drawn yarns at a temperature of <NUM> or more and <NUM> or less after crimping. In this case, heat treatment is performed on the drawn yarns preferably at a temperature of <NUM> or more and <NUM> or less, and more preferably at a temperature of <NUM> or more and <NUM> or less, before crimping. In addition, after crimping, heat treatment is performed preferably at a temperature of <NUM> or more and <NUM> or less, and more preferably at a temperature of <NUM> or more and <NUM> or less. For example, the heat treatment time may be <NUM> seconds or more and <NUM> minutes or less, and <NUM> seconds or more and <NUM> minutes or less before crimping, but is not particularly limited thereto. Moreover, for example, the heat treatment time may be <NUM> minutes or more and <NUM> minutes or less, and <NUM> minutes or more and <NUM> minutes or less after crimping, but is not particularly limited thereto. The crimp removal temperature of the obtained polyester-based fibers is reduced by subjecting the drawn yarns to heat treatment under the above-described conditions before and after crimping. In particular, when heat treatment is performed on the drawn yarns under the above-described conditions before and after crimping, the obtained polyester-based fibers are also likely to have a crimp removal temperature of <NUM> or more and <NUM> or less even after hot-water treatment. Moreover, crimps are moderately removed in polishing at a low temperature of <NUM> or more and <NUM> or less even through a step such as dyeing under hot-water conditions. Specifically, only the crimps on the napped surface layer portion of the pile fabric are likely to be removed. Thus, it is possible to obtain a pile fabric having a good appearance and excellent voluminousness.

Heat treatment performed before crimping, after crimping, or before and after crimping may be dry heat treatment or wet heat treatment. Dry heat treatment is preferred because the process is simple. It is possible to perform dry heat treatment using, e.g., a uniform hot-air dryer or a suction dryer. The heat treatment may be performed in a relaxed state. The relaxation rate may be set to, e.g., <NUM>% or less, but is not particularly limited thereto.

The polyester-based fibers of the long pile portion have a lower crimp removal temperature than the polyester-based fibers of the short pile portion. The long pile portion is located on an outer layer (surface layer) of the pile fabric and comes into contact with the human skin directly. Thus, the long pile portion more exerts influence on a feel. Thus, crimps left in the long pile portion result in a rough feel. On the other hand, the long pile portion less tends to exert influence on the voluminousness of the pile fabric compared to the short pile portion. For these reasons, the crimp removability of the polyester-based fibers of the long pile portion needs to be higher than that of the polyester-based fibers of the short pile portion. In other words, the crimp removal temperature of the polyester-based fibers of the long pile portion needs to be lower than that of the polyester-based fibers of the short pile portion. The crimp removal temperature of the polyester-based fibers of the long pile portion is preferably <NUM> or less, and more preferably <NUM> or less. The crimp removal temperature of the polyester-based fibers of the long pile portion differs from that of the polyester-based fibers of the short pile portion preferably by, e.g., <NUM> or more.

When a pressure resistant vessel is filled with the polyester-based fibers of the long pile portion together with pure water while a pressure of <NUM> kPa or more and <NUM> kPa or less is applied, and hot-water treatment is performed at <NUM> for <NUM> minutes, the crimp removal temperature of the polyester-based fibers after the hot-water treatment is preferably less than <NUM>, more preferably <NUM> or less, and further preferably <NUM> or less.

Since the crimp removal temperature of the polyester-based fibers of the long pile portion is less than <NUM>, crimps are removed well from the polyester-based fibers of the long pile portion in a relatively low temperature range of <NUM> or more and <NUM> or less in polishing, and it is possible to obtain a pile fabric having a good appearance and feel. If the crimp removal temperature is <NUM> or more, crimps are not sufficiently removed in polishing at a low temperature of <NUM> or more and <NUM> or less, and crimps on the pile fibers are hardly removed, resulting in a pile fabric having a poor appearance and feel.

From the viewpoint of easily expressing an appearance of a two-layer structure closely resembling natural fur, the single fiber fineness of the polyester-based fibers of the long pile portion is, although not particularly limited, preferably <NUM> dtex or more and <NUM> dtex or less, and more preferably <NUM> dtex or more and <NUM> dtex or less, for example. When the long pile portion contains other fibers as well as the polyester-based fibers, from the viewpoint of easily expressing an appearance of a two-layer structure closely resembling natural fur, the single fiber fineness of the other fibers are also preferably <NUM> dtex or more and <NUM> dtex or less, and more preferably <NUM> dtex or more and <NUM> dtex or less.

In one or more embodiments of the present invention, when the pile fabric includes the medium pile portion, polyester-based fibers having a crimp removal temperature of <NUM> or less can be used for the medium pile portion.

A method of producing the polyester-based fibers is not particularly limited. The polyester-based fibers can be produced in the same manner as usual polyester-based fibers except the steps described above. The polyester-based fibers can be produced by, e.g., melt kneading, using various general kneading machines, the polyester-based resin or a polyester-based resin composition obtained by dry blending the polyester-based resin and an additive agent, pelletizing the polyester-based resin or the polyester-based resin composition, and then melt spinning the resulting pellets. Melt spinning is performed while the temperatures (spinning temperatures) of, e.g., an extruder, a gear pump, and a spinneret are set to <NUM> or more and <NUM> or less. The obtained spun yarns are passed through a heated tube, then cooled to a temperature of not more than the glass transition point of the polyester-based resin, and wound up at a speed of <NUM>/min or more and <NUM>/min or less to obtain spun yarns (undrawn yarns). The spun yarns (undrawn yarns) can be drawn through hot drawing. The heating means for the hot drawing may be, e.g., a heating roller, a heat plate, a steam jet apparatus, or a hot water bath, and they can be used in combination as appropriate.

Crimping can be performed by a known crimp imparting apparatus such as a gear crimper or a stuffing box crimper. Similarly to usual crimping, it is possible to crimp the polyester-based fibers in a state in which the polyester-based fibers are preheated to a temperature that is higher than or equal to a softening temperature. Similarly to usual crimping, preheating can be performed by wet heat, e.g., by steam at <NUM> or more and <NUM> or less.

In one or more embodiments of the present invention, the polyester-based fibers have a Young's modulus of preferably <NUM> GPa or more, and more preferably <NUM> GPa or more. This is because the higher the Young's modulus is, the higher the rigidity of the fibers is, and the better the voluminousness of the pile fabric is.

In one or more embodiments of the present invention, from the viewpoint of further improving the appearance, voluminousness, and compression recoverability, the pile fabric preferably includes the short pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion and the long pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion, and the pile fabric more preferably includes the short pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion and the long pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion.

In one or more embodiments of the present invention, from the viewpoint of further improving the appearance, voluminousness, and compression recoverability, the pile fabric may include the short pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion, the medium pile portion in an amount of <NUM>% by weight or less of the total weight of the pile portion, and the long pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion, and the pile fabric may include the short pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion, the medium pile portion in an amount of <NUM>% by weight or less of the total weight of the pile portion, and the long pile portion in an amount of <NUM>% by weight or more and <NUM>% by weight or less of the total weight of the pile portion.

Hereinafter, one or more embodiments of the present invention will be specifically described by way of examples and comparative examples. Note that the present invention is not limited to these examples.

First, a measuring method and an evaluation method used in the examples and comparative examples will be described.

Polyester-based fibers were bundled to prepare a fiber bundle with <NUM> dtex. Both ends of the fiber bundle were trimmed such that the resulting sample had a length of about <NUM>. The sample was suspended vertically in a hot-air convection dryer. A <NUM>-weight was suspended from a lower end of the fiber bundle (a load of <NUM>/dtex was applied to the fiber bundle). In this state, the sample was subjected to heat treatment for <NUM> seconds at a predetermined temperature starting from <NUM> and increasing in increments of <NUM>. After each instance of heat treatment, a length A of the fiber bundle under a load of <NUM>/dtex, and a length B of the fiber bundle under no load after the weight had been removed were measured. The measurement thereof was performed five times at each temperature. The differences between the values of A and B were divided by A, and the values thus obtained were averaged. Out of the temperatures, the minimum temperature at which the average was less than <NUM>% was referred to as the "crimp removal temperature". That is, the crimp removal temperature indicates the minimum temperature that satisfies the following numerical formula (<NUM>).

The crimp removability of pile portions of a pile fabric was sensory evaluated based on the following five criteria. When the criterion of the crimp removability was <NUM>, only crimps on a napped surface layer portion of the pile fabric were removed. From the viewpoint of achieve voluminousness, an appearance, and a feel, crimps are preferably left appropriately in a short pile portion, and the crimp removability of the short pile portion is preferably <NUM>. From the viewpoints of an appearance and a feel, crimps are preferably removed neatly in a long pile portion, and the crimp removability of the long pile portion is preferably <NUM>. The crimp removability of a medium pile portion is preferably <NUM> or <NUM>.

The voluminousness of a pile fabric was evaluated based on the following criteria. Reference photographs for the respective criteria are shown in <FIG>. Specifically, <FIG> shows reference photographs when a pile fabric had good voluminousness, and <FIG> shows reference photographs when a pile fabric had poor voluminousness.

Good: When napped portions of two pile fabrics were placed on each other and a pressure of <NUM> Pa was applied thereto, the thickness of the pile fabrics placed on each other was about <NUM>% or more of the thickness of the pile fabrics obtained before the pressure was applied, and the pile fabrics had sufficient voluminousness.

Poor: When napped portions of two pile fabrics were placed on each other and a pressure of <NUM> Pa was applied thereto, the thickness of the pile fabrics placed on each other was less than about <NUM>% of the thickness of the pile fabrics obtained before the pressure was applied, and the pile fabrics had insufficient voluminousness.

A surface of a napped portion (pile portion) of a pile fabric was observed, and was sensory evaluated based on the following criteria.

Good: The surface of a pile fabric was observed to be smooth.

Poor: A pile fabric was observed to be split.

A pile fabric was cut into a square with a weight of <NUM>. The fabric piece thus obtained was packed into a <NUM> columnar container and allowed to stand still at room temperature. After <NUM> hours, the fabric piece was taken out from the container. The compression recoverability of the fabric piece was evaluated based on the following criteria.

Good: The fabric piece before and after packing did not differ in appearance.

Poor: Any of the following conditions was observed in the fabric piece.

Polyethylene terephthalate (PET; EFG-<NUM> manufactured by Bell Polyester Products, Inc. ) having an intrinsic viscosity (IV value) of <NUM> was spun into undrawn yarns having a single fiber fineness of <NUM> dtex by a usual spinning machine using a spinneret with <NUM> holes having a five finger shape in cross section at a speed of <NUM>/min and a spinning temperature of <NUM>. At this time, <NUM> parts by weight of PET was blended with <NUM> parts by weight of titanium oxide as a delustering agent and <NUM> parts by weight of melamine-modified silica. Next, the undrawn yarns were drawn by <NUM>% in a uniform hot-air drawing machine set at <NUM> and immediately subjected to heat treatment while subjected to a <NUM>% limited shrinkage in a uniform hot-air heat treatment machine set at <NUM> for one minute to obtain heat treated yarns. After the heat treated yarns were assembled to an appropriate fineness, the heat treated yarns were crimped through preheating at <NUM> by a stuffing box crimper. The yarns were subjected to heat treatment in a uniform hot-air dryer set at <NUM> for <NUM> minutes in a relaxed state in which the relaxation rate was <NUM>% or less. Thus, crimped fibers having a single fiber fineness of <NUM> dtex and a five skewered-dumpling shape in cross section were obtained. Finally, the crimped fibers were cut to <NUM> to obtain a raw cotton 1A for a pile fabric. The raw cotton 1A had a crimp removal temperature of <NUM>.

A raw cotton 1B for a pile fabric was obtained in the same manner as the raw cotton 1A for a pile fabric. However, spinning was performed using a spinneret with <NUM> holes having a Y shape in cross section at a winding speed of <NUM>/min to obtain undrawn yarns having a single fiber fineness of <NUM> dtex. The draw ratio was set to <NUM>%. The heat treatment temperature after crimping was set to <NUM>. Thus, crimped fibers having a single fiber fineness of <NUM> dtex and a Y shape in cross section were obtained. Finally, the crimped fibers were cut to <NUM> to obtain the raw cotton 1B for a pile fabric. The raw cotton 1B had a crimp removal temperature of <NUM>.

A raw cotton 1C for a pile fabric was obtained in the same manner as the raw cotton 1A for a pile fabric. However, spinning was performed using a spinneret with <NUM> holes having a cocoon shape in cross section at a winding speed of <NUM>/min. Moreover, PET was blended with <NUM> parts by weight of titanium oxide, <NUM> parts by weight of modified silica, and <NUM> parts by weight of a brown pigment compound. Furthermore, the draw ratio was set to <NUM>%. The heat treatment temperature after drawing and before crimping was set to <NUM>. Heat treatment after crimping was not performed. Thus, crimped fibers having a single fiber fineness of <NUM> dtex and a cocoon shape in cross section were obtained. Finally, the crimped fibers were cut to <NUM> to obtain the raw cotton 1C for a pile fabric. The raw cotton 1C had a crimp removal temperature of <NUM>.

Crimped fibers having a single fiber fineness of <NUM> dtex and a five skewered-dumpling shape in cross section were obtained in the same manner as in Example <NUM> except that the yarns were not subjected to heat treatment before crimping, but were subjected to heat treatment in a uniform hot-air dryer set at <NUM> for <NUM> minutes after crimping. A raw cotton 1D had a crimp removal temperature of <NUM>.

A raw cotton 1E for a pile fabric was obtained in the same manner as the raw cotton 1A for a pile fabric. However, spinning was performed using a spinneret with <NUM> holes having a four finger shape in cross section at a winding speed of <NUM>/min to obtain undrawn yarns having a single fiber fineness of <NUM> dtex. Moreover, the draw ratio was set to <NUM>%. Heat treatment after crimping was performed for <NUM> minutes. Thus, crimped fibers having a single fiber fineness of <NUM> dtex and a four skewered-dumpling shape in cross section were obtained. Finally, the raw cotton 1E for a pile fabric was obtained. The raw cotton 1E had a crimp removal temperature of <NUM>.

A raw cotton 1F for a pile fabric was obtained in the same manner as the raw cotton 1A for a pile fabric. However, spinning was performed using a spinneret with <NUM> holes having a five finger shape in cross section at a winding speed of <NUM>/min. Moreover, PET was blended with <NUM> parts by weight of titanium oxide and <NUM> parts by weight of modified silica. Furthermore, the draw ratio was set to <NUM>%. Heat treatment temperature after drawing and before crimping was set to <NUM>. Heat treatment after crimping was not performed. Thus, crimped fibers having a single fiber fineness of <NUM> dtex and a five skewered-dumpling shape in cross section were obtained. Finally, the crimped fibers were cut to <NUM> to obtain the raw cotton 1F for a pile fabric. The raw cotton <NUM> F had a crimp removal temperature of <NUM>.

Modacrylic fibers (trade name "Kanekalon (registered trademark) RCL" manufactured by Kaneka Corporation) having a softening point of <NUM> to <NUM>, a fineness of <NUM> dtex, and a cut length of <NUM> were used (hereinafter, simply referred to as "RCL").

Modacrylic fibers (trade name "Kanekalon (registered trademark) ELP" manufactured by Kaneka Corporation) having a softening point of <NUM> to <NUM>, a fineness of <NUM> dtex, and a cut length of <NUM> were used (hereinafter, simply referred to as "ELP").

Modacrylic fibers (trade name "Kanekalon (registered trademark) AH" manufactured by Kaneka Corporation) having a softening point of <NUM> to <NUM>, a fineness of <NUM> dtex, and a cut length of <NUM> were used (hereinafter, simply referred to as "AH").

The raw cottons 1A, 1B, and 1C for a pile fabric thus obtained were used in a weight ratio of <NUM>:<NUM>:<NUM> to produce a sliver. The obtained sliver was knitted into a pile fabric by a sliver knitting machine. The raw cottons 1A and 1B were used for a short pile portion. The raw cotton 1C was used for a long pile portion. Next, pre-polishing was performed at <NUM>, a back surface of the pile fabric was back-coated with an acrylic acid ester-based adhesive, and tentering was performed. Next, polishing was performed at <NUM> three times, at <NUM> three times, and at <NUM> three times. Thus, a pile fabric having a basis weight of about <NUM>/m<NUM> was obtained.

A pile fabric having a basis weight of about <NUM>/m<NUM> was produced in the same manner as in Example <NUM> except that the raw cottons 1E and 1F for a pile fabric were used in a weight ratio of <NUM>:<NUM> as raw cottons for a pile fabric. The raw cotton 1E was used for a short pile portion. The raw cotton 1F was used for a long pile portion.

A pile fabric having a basis weight of about <NUM>/m<NUM> was produced in the same manner as in Example <NUM> except that the raw cottons 1A and 1B for a pile fabric, RCL, and ELP were used in a weight ratio of <NUM>:<NUM>:<NUM>:<NUM> as raw cottons for a pile fabric, RCL was used for a medium pile portion, and ELP was used for a long pile portion.

A pile fabric having a basis weight of about <NUM>/m<NUM> was produced in the same manner as in Example <NUM> except that the raw cotton 1D for a pile fabric and ELP were used in a weight ratio of <NUM>:<NUM> as raw cottons for a pile fabric, the raw cotton 1D was used for a short pile portion, and ELP was used for a long pile portion.

A pile fabric having a basis weight of about <NUM>/m<NUM> was produced in the same manner as in Example <NUM> except that the raw cottons AH, RCL, and ELP for a pile fabric were used in a weight ratio of <NUM>:<NUM>:<NUM> as raw cottons for a pile fabric, AH was used for a short pile portion, RCL was used for a medium pile portion, and ELP was used for a long pile portion.

In each of the examples and comparative examples, the crimp removability, appearance, compression recoverability, and voluminousness of the pile fabric thus obtained were evaluated as above. Table <NUM> indicates the results.

As understood from Table <NUM>, all the crimp removability, appearance, voluminousness, and compression recoverability of the pile fabric were good in each of Examples <NUM> and <NUM> in which the PET fibers having a predetermined crimp removal temperature were used both for the long pile portion and for the short pile portion.

The crimp removability, appearance, and voluminousness of the pile fabric were good in Comparative Example <NUM> in which the PET fibers having a predetermined crimp removal temperature were used for the short pile portion and only modacrylic fibers RCL and ELP were used for the long pile portion. However, the compression recoverability of the pile fabric was poor in Comparative Example <NUM>. The crimp removability of the short pile portion of the pile fabric was <NUM> in Comparative Example <NUM> in which the PET fibers having a crimp removal temperature of <NUM> were used for the short pile portion and crimps were not able to be removed in the pile fabric. As a result of this, the appearance and compression recoverability thereof were poor. The crimp removability and appearance were good, but the voluminousness and compression recoverability were poor in Comparative Example <NUM> in which the modacrylic fibers were used both for the long pile portion and for the short pile portion.

Claim 1:
A pile fabric, comprising:
a pile portion that comprises a long pile portion and a short pile portion,
wherein an average pile length of the long pile portion differs from an average pile length of the short pile portion by <NUM> or more as measured in accordance with the desciption,
characterized in that
the long pile portion comprises crimped polyester-based fibers in an amount of <NUM>% by weight or more,
the short pile portion comprises crimped polyester-based fibers in an amount of <NUM>% by weight or more,
a crimp removal temperature of the crimped polyester-based fibers of the long pile portion is lower than a crimp removal temperature of the crimped polyester-based fibers of the short pile portion,
the crimp removal temperature of the crimped polyester-based fibers of the short pile portion is <NUM> or more and <NUM> or less, and
each of the crimp removal temperatures indicates a minimum temperature that satisfies the following numerical formula (<NUM>): <MAT> where, in the formula (<NUM>),
A represents a length of a fiber bundle of the crimped polyester-based fibers under a load of <NUM>/dtex after the fiber bundle is subjected to dry heat treatment at a predetermined temperature for <NUM> seconds under a load of <NUM>/dtex, and
B represents a length of the fiber bundle of the crimped polyester-based fibers under no load after the fiber bundle is subjected to the dry heat treatment at the predetermined temperature for <NUM> seconds under a load of <NUM>/dtex.