JP2011208346A - Polyester fiber structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester fiber structure which has low shrinkage and low tensile strength at a high temperature, and attains compatibility between dimensional stability and formability in hot forming.SOLUTION: The polyester fiber structure is a fiber structure which uses a part or all of polyester fiber formed by kneading 5-95 mass% of polytrimethylene terephthalate resin and 95-5 mass% of polyethylene terephthalate resin, and is a polyester fiber structure having one peak of 210-220 as a melting point peak of the fiber. The tensile strength retention at high temperature of the fiber structure is 67% or less in length and 82% or less in width. The fiber structure is a needle-punched nonwoven fabric.

Description

  The present invention relates to a polyester fiber structure that can achieve a reduction in tensile strength at high temperatures with a low shrinkage rate.

  In recent years, there has been concern about global warming caused by mass consumption of petroleum resources and depletion of petroleum resources associated with mass consumption, and awareness of the environment is increasing on a global scale. In such a background, a material having a low environmental load is demanded.

  In order to satisfy the above required properties, studies have been made on fabrics using polylactic acid fibers or polytrimethylene terephthalate (PTT) fibers in addition to conventionally used polyamide fibers, polypropylene fibers and polyethylene terephthalate fibers. .

  Among materials having a low environmental load, polytrimethylene terephthalate (PTT) fibers have a low initial tensile resistance, so that the texture of the nonwoven fabric is soft and should be noted as a fabric material.

  In particular, a nonwoven fabric excellent in texture and air permeability is required to play a role as a nonwoven fabric in interior materials and clothing.

  However, since the fabric using polytrimethylene terephthalate fiber has a high shrinkage rate, there is a problem in dimensional stability when it is made into a fabric.

  On the other hand, polyethylene terephthalate fibers have a low shrinkage rate and can provide a fabric with excellent dimensional stability, and are widely used from clothing to industrial materials. However, polyethylene terephthalate fiber is excellent in applications that require dimensional stability at high temperatures because of its high tensile strength retention in a high-temperature atmosphere, but it is used for heat molding in vehicle interior materials and interior materials. In this case, there is a demand for improvement because it may lead to skin breakage or material destruction.

  Conventionally, in order to solve these problems, a core-sheath composite fiber in which the core is polyethylene terephthalate and polytrimethylene terephthalate is used for the sheath has been proposed (see Patent Document 1). However, in this proposal, the shrinkage rate is improved by using polyethylene terephthalate having a low shrinkage rate as the core part. However, since polyethylene terephthalate is present in the core part, the tensile strength retention rate at high temperature is obtained from polyethylene terephthalate fiber. The fact is that the moldability is not improved.

  Further, there has been proposed a short fiber having a core-sheath composite structure in which the core is a polyester in which polyethylene terephthalate and polytrimethylene terephthalate are melt-mixed, and the sheath is a polyester mainly composed of polytrimethylene terephthalate. (See Patent Document 2). The fiber proposed here has a soft texture, anti-penetration property, contact cooling sensation and dyeability, but uses polytrimethylene terephthalate in the core, which means that the shrinkage of the fiber is suppressed. There were still insufficient points in view.

JP 2007-154374 A JP 2009-197339 A

  Accordingly, an object of the present invention is to provide a polyester fiber structure having a low shrinkage rate, a low high-temperature tensile strength, and having both dimensional stability and moldability during heat molding.

  The present invention is intended to solve the problems that could not be achieved by the above-described conventional method, and the polyester fiber structure of the present invention comprises 5 to 95% by mass of polytrimethylene terephthalate resin and 95 to 5 of polyethylene terephthalate resin. A polyester fiber structure using a part or all of a polyester fiber obtained by kneading mass%, wherein the fiber has a melting point peak of 210 to 220.

  According to a preferred aspect of the polyester fiber structure of the present invention, the tensile strength retention at high temperature of the fiber structure is 67% or less for the vertical and 82% or less for the horizontal.

  According to a preferred aspect of the polyester fiber structure of the present invention, the fiber structure is a needle punched nonwoven fabric.

  According to the present invention, a polyester fiber structure having a low shrinkage rate and a low high temperature tensile strength can be obtained. For this reason, it can use suitably for the vehicle interior material, interior material, etc. of the material which heat-molds. In addition, it is possible to obtain a fabric with little dimensional change at the time of heat molding and less heat fusion of the fibers and hair fall.

  In the present invention, as a result of intensive studies to solve the problems that could not be achieved by the above-described conventional method, polyester fiber formed by kneading 5 to 95% by mass of polytrimethylene terephthalate resin and 95 to 5% by mass of polyethylene terephthalate resin. Is a fiber structure using a part or all of the fiber, and the melting point peak of the fiber is one peak of 210 to 220. The present inventors have found that a reduction in the tensile strength can be achieved.

  The polytrimethylene terephthalate resin (hereinafter sometimes referred to as PTT resin) used in the present invention is a repeating unit composed of a 1,3-trimethylene glycol component and a terephthalic acid component (trimethylene terephthalate unit). ) And having a methylene chain with 3 carbon atoms in the glycol component, the crystal structure itself expands and contracts with respect to elongation deformation.

  The 1,3-trimethylene glycol constituting the trimethylene terephthalate unit is preferably derived from a biomass material from the viewpoint of low environmental load.

  In the present invention, the PTT resin may be copolymerized with other components in addition to the trimethylene terephthalate unit. However, in taking advantage of the characteristics of the PTT resin, the trimethylene terephthalate unit may be 90 mol% or more. Preferably, the trimethylene terephthalate unit is more preferably 92 mol% or more, and still more preferably 95 mol% or more.

  Examples of the dicarboxylic acid component that is copolymerized with the PTT resin include isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 4, Aromatic dicarboxylic acid components such as 4′diphenyldicarboxylic acid, 4,4′diphenyletherdicarboxylic acid, 4,4′diphenylsulfonedicarboxylic acid and 5-sodiumsulfoisophthalic acid, succinic acid, adipic acid, suberic acid, sebacic acid, Aliphatic dicarboxylic acid components such as dodecanedioic acid, dimer acid and eicosandioic acid can be used.

  Examples of the glycol component copolymerized with the PTT resin include ethylene glycol, 1,2-trimethylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol and 2,2 ′ Bis (4′-β-hydroxyethoxyphenyl) propane or the like can be used.

  These copolymer components may be used individually by 1 type, and may use 2 or more types together.

  Further, the PTT resin may contain additives such as other polymers, matting agents, particles, flame retardants, antistatic agents, antioxidants, and ultraviolet absorbers depending on the purpose.

  In addition, a dimer in which two trimethylene terephthalates are linked in a cyclic manner (hereinafter sometimes referred to as “cyclic dimer”) may exist in the PTT resin, but the content of the cyclic dimer in the PTT resin. Is preferably 3% by mass or less, more preferably 2.5% by mass or less, and still more preferably 2% by mass or less. By suppressing the content of the cyclic dimer in the PTT resin to 3% by mass or less, the hydrolysis resistance of the PTT resin can be improved. Regarding the relationship between the cyclic dimer and the hydrolyzability, it is presumed that the cyclic dimer becomes a trimethylene terephthalate monomer by hydrolysis, and the hydrolysis is promoted by the catalytic action of the monomer.

  The intrinsic viscosity of the PTT resin is preferably 0.8 to 2 dl / g, more preferably 1 to 1.8 dl / g, and still more preferably 1.2 to 1.6 dl / g. By setting the intrinsic viscosity of the PTT resin to 0.8 dl / g or more, the molecular orientation of the PTT resin is improved, and the elastic recovery property of the crimped yarn and the fastness of elastic recovery are improved. On the other hand, by setting the intrinsic viscosity of the PTT resin to 2 dl / g or less, it is possible to suppress an abrupt decrease in molecular weight during melt spinning, and to suppress instability of composite spinning due to destabilization of polymer melt flow.

The intrinsic viscosity was measured by adding 10 ml of o-chlorophenol (hereinafter abbreviated as OCP) to 0.8 g of a sample, dissolving at 160 ° C. for 30 minutes, and then slowly cooling to obtain a measurement solution. About the said measurement solution, relative viscosity (eta) _r is calculated | required by following Formula using an Ostwald viscometer at the temperature of 25 degreeC, and intrinsic viscosity is calculated by a formula one after another.
η _r = η / η ₀ = (t × d) / (t ₀ × d ₀ )
Intrinsic viscosity = 0.0242 η _r +0.2634
Where η: viscosity of the measurement solution η ₀ : OCP viscosity t: time of solution fall (seconds)
d: density of the solution (g / cm ³ )
t ₀ : OCP fall time (seconds)
d ₀ : Density of OCP (g / cm ³ ).

  The polyethylene terephthalate resin (hereinafter sometimes referred to as PET) kneaded with the PTT resin used in the present invention is a polyester containing an ethylene terephthalate unit, and other components are copolymerized in addition to the ethylene terephthalate unit. It is also a preferred embodiment. Examples of the copolymer component include isophthalic acid and bisphenol A. The amount of copolymerization is preferably 0.1 mol% or more in order to improve the fluidity of the PET resin. On the other hand, in order to suppress delayed recovery of the PTT resin, the copolymerization amount is preferably 10 mol% or less. Further, the PET resin may contain additives such as other polymers, matting agents, particles, flame retardants, antistatic agents, antioxidants and ultraviolet absorbers depending on the purpose.

  The intrinsic viscosity of the PET resin is preferably 0.4 to 0.6 dl / g, more preferably 0.43 to 0.56 dl / g, and still more preferably 0.46 to 0.53 dl / g. is there. By setting the intrinsic viscosity of the PET resin to 0.6 dl / g or less, stable composite spinning and composite fiber formation with the PTT resin can be achieved. On the other hand, when the intrinsic viscosity of the PET resin is 0.4 dl / g or more, heat resistance, strength, hydrolysis resistance, and the like can be maintained. In addition, for the purpose of reducing environmental impact and reducing greenhouse gas emissions during production, chemical recycling is achieved by decomposing PET bottles, material recycling products using fiber and film scraps, and clothing products into chemical monomers and repolymerizing them. Goods etc. may be used.

In the same manner as the PTT measurement method, the intrinsic viscosity is measured by adding 10 ml of o-chlorophenol (hereinafter abbreviated as OCP) to 0.8 g of sample, dissolving at 160 ° C. for 30 minutes, and then gradually cooling. A measurement solution was obtained. About the said measurement solution, relative viscosity (eta) _r is calculated | required by following Formula using an Ostwald viscometer at the temperature of 25 degreeC, and intrinsic viscosity is calculated by a formula one after another.
η _r = η / η ₀ = (t × d) / (t ₀ × d ₀ )
Intrinsic viscosity = 0.0242 η _r +0.2634
Where η: viscosity of the measurement solution η ₀ : OCP viscosity t: time of solution fall (seconds)
d: density of the solution (g / cm ³ )
t ₀ : OCP fall time (seconds)
d ₀ : Density of OCP (g / cm ³ ).

  Next, the effect when kneading PTT and PET will be described.

  The polyester fiber used in the polyester fiber structure of the present invention is obtained by kneading 5 to 95% by mass of polytrimethylene terephthalate resin and 95 to 5% by mass of polyethylene terephthalate resin, preferably 220 to 285 ° C. It can be obtained by fiberizing a resin melt-kneaded at a temperature. A preferable kneading ratio of the polytrimethylene terephthalate resin and the polyethylene terephthalate resin is 80 to 20% by mass of the PTT resin and 20 to 80% by mass of the PET resin, more preferably 70 to 30% by mass of the PTT resin, and 30 to 70% by mass of the PET resin. %.

  By putting PTT resin and PET resin into uniaxial or biaxial extruders from separate hoppers and melt-kneading them at a temperature of 220 to 285 ° C. for 2 to 7 minutes, the ester groups of the PTT resin and the ester groups of the PET resin Causes an exchange reaction and is completely compatibilized, so that uniform fibers can be obtained.

Therefore, only one peak peak appears at 210 to 220 ° C. of the melting point peak of the polyester fiber obtained by melt-kneading the PTT resin and the PET resin. Using a differential scanning calorimeter DSC-60 manufactured by Shimadzu Corporation, the maximum melting exothermic peak temperature when the temperature is raised to a temperature of 2 ° C., 2 ° C. in nitrogen, at a heating rate of 10 ° C./min, 300 ° C. ( _Tm ).

  When the melting point peak is in the range of 210 to 220 ° C., it becomes possible to obtain a fabric with less fiber fusion and hair fall during molding. The melting point peak tends to increase as the proportion of PET increases, and tends to decrease as the proportion of PTT increases.

  Also, complete compatibilization means that almost all ester groups of the PTT resin and the PET resin undergo a transesterification reaction, and the DSC peak becomes one peak. An alloy fiber made of a core-sheath composite yarn or an incompatible resin that is not compatibilized has two DSC peaks, and each component can be confirmed from the cross section of the fiber. The peak is one peak, and the fiber cross section is uniform, and each component cannot be confirmed from the cross-sectional photograph.

  The polyester fiber structure of the present invention can obtain a fiber with little variation in quality by using polyester fiber in which PTT resin and PET resin are completely compatible. Further, when the PET resin and the PTT resin are completely compatible, the melting point of the resin shifts to a lower temperature than the melting point of the PET resin, which is 255 to 260 ° C., and the melting point of the PTT resin, 220 to 230 ° C. For this reason, the softening point is also shifted to a low temperature, the resin is easily deformed by physical force during heating, and a fiber structure excellent in moldability can be obtained.

  Next, the characteristics of the polyester fiber used in the present invention will be described.

  The polyester fibers used in the present invention may be long fibers or short fibers, and fibers suitable for the polyester fiber structure to be used can be used. For example, when the fiber structure is a circular knitting or a tricot, long fibers are preferably used from the viewpoints of productivity and fabric quality stability. When the fiber structure is a non-woven fabric, a long-fiber non-woven fabric such as spunbond is directly formed after spinning, but a short fiber is used for the non-woven fabric such as spunlace or needle punch.

  The single fiber fineness of the polyester fiber used in the present invention is preferably 0.5 to 30 dtex. The single fiber fineness is more preferably 1.0 to 15 dtex, still more preferably 1.5 to 7 dtex.

  By setting the single fiber fineness to 1.5 dtex or more, yarn (fiber) breakage during knitting or card passing can be suppressed, and a fabric excellent in surface quality can be obtained. In addition, by setting the single fiber fineness to 7 dtex or less, it is possible to suppress the fabric from becoming hard.

  The fiber strength of the polyester fiber used in the present invention is preferably 1.5 to 9.0 cN / dtex. By setting the fiber strength to 1.5 cN / dtex or more, yarn (fiber) breakage during knitting or card passing can be suppressed, and a fabric excellent in surface quality can be provided. Moreover, it is difficult to obtain a fiber having a fiber strength of 9.0 cN / dtex or more from a normal fiber process.

  The elongation of the polyester fiber used in the present invention is preferably in the range of 50 to 150%. When the elongation is less than 50%, the texture of the fabric tends to be hard. On the other hand, those having an elongation exceeding 150% tend to be inferior in surface quality because they tend to generate neps when passing through the card.

  If the polyester fiber used in the present invention is a long fiber, it may be false twisted, and the false twisting method may be any method such as pin, friction, nip belt and air twisting. The heater may be either a contact type or a non-contact type.

  In addition, if the polyester fiber used in the present invention is a short fiber, the cut length can be arbitrarily determined according to the fiber structure such as a fabric. It is preferable that it is 10-100 mm. The fiber length is more preferably 30 to 80 mm. When the fiber length is less than 10 mm, the entanglement force between the fibers tends to be small and the card passing tends to be difficult. On the other hand, if the fiber length exceeds 100 mm, a nep is likely to occur when the card passes and the surface quality tends to be inferior.

  The number of crimps of the polyester fiber used in the present invention is preferably 5-25 pieces / 25 mm, preferably 8-20 pieces / 25 mm, more preferably 10-18 pieces / 25 mm. A needle punched nonwoven fabric having a good texture can be obtained without any problem in the entanglement of the fibers. If the number of crimps is less than 5 pieces / 25 mm, the fiber entanglement is insufficient, and the web may be lost in the laminating process after passing through the card. On the other hand, if the number of crimps exceeds 25 pieces / 25 mm, a nep is likely to occur and the surface quality tends to be inferior.

  Moreover, if the degree of crimp is 5 to 25%, preferably 8 to 20%, and more preferably 10 to 18%, a nonwoven fabric having both process passability and surface quality can be obtained. When the degree of crimp is less than 5%, the fiber entanglement is insufficient, and the web may be lost in the lamination process after passing through the card. On the other hand, if the degree of crimp exceeds 25%, nep tends to occur and the surface quality tends to be inferior.

  The frequency ratio obtained by dividing the degree of crimp by the number of crimps is in the range of 0.3 to 3.0, preferably 0.5 to 2.0, and more preferably 0.8 to 1.5. And the entanglement of the fiber in a needle punch process becomes uniform, and the nonwoven fabric whose surface quality is smooth can be obtained.

  A large power ratio means that the crimp wave imparted to the fiber becomes large.

  Moreover, if the frequency ratio is small, it means that the crimp wave given to the crimp is small. When the frequency ratio exceeds 3.0, the crimped wave becomes too large, so that the fibers are extremely difficult to be entangled and the card passing property is deteriorated. On the other hand, if it is smaller than 0.3, the crimp wave becomes too small, so that the card spinning property is lowered, and process defects such as nep and card winding tend to occur. If the shrinkage rate of a polyester fiber is a boiling water shrinkage rate, it is preferably 5 to 20%, more preferably 5 to 15%. Further, the dry heat shrinkage of the fiber is preferably 0 to 3%, more preferably 0 to 2% at a temperature of 150 ° C.

  The cross-sectional shape of the polyester fiber includes a round cross-section, a hollow cross-section, a porous hollow cross-section, a multi-leaf cross-section such as a trilobal cross-section (triangular cross-section, Y cross-section, T cross-section, etc.) and a four-leaf cross-section (X cross-section). Etc. can be adopted.

  The polyester fiber used in the present invention is preferably provided with a spinning oil containing a smoothing agent. Examples of the smoothing agent include fatty acid esters, polyhydric alcohol esters, ether esters, polyethers, silicones, and mineral oils. These smoothing agents may be used as a single component, or a plurality of components may be mixed and used.

  By adding an oil agent containing the above-mentioned smoothing agent to the short fiber, the slipping property of the short fiber is further improved, and the processability in spinning and drawing, carding and spinning, and the obtained short fiber itself In addition to improving the quality of crimped spots and fluff, it is possible to further improve the spreadability of the short fibers and the dispersibility of the short fibers in the fiber structure. Moreover, it is a preferable aspect that the adhesion amount of the smoothing agent is 0.1 to 2% by mass because the card passing property and the productivity at the time of producing the nonwoven fabric are good. The adhesion amount of the smoothing agent is more preferably 0.2 to 0.7% by mass.

  In the present invention, in addition to the smoothing agent, the component constituting the oil agent is an emulsifier that emulsifies the oil agent in water to lower the viscosity, thereby improving adhesion and permeability to fibers and yarns, and optionally an antistatic agent. , An ionic surfactant, a sizing agent, a rust inhibitor, a preservative, or an antioxidant can be appropriately used.

  Next, the aspect of the polyester fiber structure of the present invention will be described.

  A representative example of the polyester fiber structure of the present invention is a (fiber) fabric. Examples of the (fiber) fabric used as the polyester fiber structure in the present invention include woven fabrics, knitted fabrics, and nonwoven fabrics. From the viewpoint of moldability, knitted fabrics and nonwoven fabrics are preferably used. As a more preferable fabric, a nonwoven fabric, especially a needle punched nonwoven fabric is mentioned as a fabric used for deep drawing.

  In addition, the polyester fiber structure of the present invention includes braided cords, twisted cords, tape cords, laces, straps such as tassels (bundles) and strap belts, belts such as vegetation belts, fixed belts, seat belts, fishing nets, anti-corrosion Examples include beasts, birds, insect nets, insect nets, nets such as vegetation nets, curing nets, papers, and flocked products obtained by electrostatic flocking on plastic substrates.

  In the present invention, when a circular knitted fabric is selected as the polyester fiber structure, a knitting machine can be knitted using a flat knitting machine, a circular knitting machine, etc., and single and double knitting machines can be used. Can do.

  As the knitting structure, for example, a double circular knitting machine such as Ponchiroma, Mockrody, and Smooth, and a knitting structure of a single circular knitted fabric such as Tendon and Kanoko can be used.

  In the present invention, it is also a preferable aspect to impart functions such as moisture absorption, water absorption, antibacterial, deodorization, quick drying and flame retardancy to the circular knitted fabric. Examples of the function imparting method include a dip-nip method and a spray method. Moreover, you may print a pattern by methods, such as textile printing.

  In the present invention, when a warp knitted fabric is selected as the polyester fiber structure, the structure form thereof is, for example, 4-5 / 1-0, 4-5 / 1 for the structure of 2 sheets of front yarn. -0, the structure of the back yarn 2 sheets is 1-0 / 1-2, 1-0 / 1-2, and the 3 sheet kite is 4-5 / 1-0, middle structure of the front yarn The yarn structure is 1-0 / 1-2, the back yarn structure is 1-0 / 1-2, and in the case of two sheets, the front yarn structure is 2-3 / 1-0 and the back yarn structure is Examples thereof include those having 1-0 / 1-2 and those having a front yarn structure of 3-4 / 1-0 and a back yarn structure of 1-0 / 1-2.

  In the present invention, known fibers may be mixed as the polyester fiber structure. For example, a long fiber of synthetic fiber such as polyethylene terephthalate fiber or nylon fiber and the polyester fiber of the present invention can be mixed and used.

  As a method of blending, in the case of false twisting or twisting, in the case of warp knitted or circular knitted fabric, the polyester fiber of the present invention is used for the front part, and polyethylene terephthalate or nylon long fiber is used for the back part. In addition, a method of mixing fibers is also possible.

  In the present invention, circular knitting and warp knitting can be raised. Examples of raising methods include needle raising and emery raising.

  Moreover, about finishing, it is also a preferable aspect to provide functions, such as moisture absorption, water absorption, antibacterial, deodorization, quick-drying, and a flame retardance, to a fiber structure. Examples of the function imparting method include a dip-nip method and a spray method. Moreover, you may print a pattern by methods, such as textile printing.

  In the present invention, when a nonwoven fabric is selected as the polyester fiber structure, methods such as a spunbond method, a melt blow method, a spunlace method, and a needle punch method are used as the production means. In particular, as a method for obtaining a polyester fiber structure suitable for heat molding, a needle punch method may be mentioned. A needle punched nonwoven fabric is obtained as follows, for example. First, polyester fibers are mixed in a predetermined ratio and carded with a card machine, and then a web is laminated using a cross wrapper to match a predetermined basis weight. Thereafter, the web is punched with a needle punch machine, and the short fibers are entangled to obtain a nonwoven fabric.

At this time, the number of laminated webs is preferably 8 to 30. If the amount of web is less than 8, the fabric weight per unit area of the nonwoven fabric increases, and the surface quality of the nonwoven fabric tends to deteriorate. If the amount of web exceeds 30, the productivity tends to deteriorate. Further, when punching is performed, the needle count is preferably # 36 to # 42 and the number of needles is preferably 300 to 700 / cm ² , and a needle punched nonwoven fabric excellent in surface quality and texture can be obtained.

  When using a spunlace method or a needle punch method as a means for producing a polyester fiber structure, other fibers may be blended with the polyester fiber used in the present invention. For example, natural fibers such as cotton, wool and hemp, semi-synthetic fibers such as rayon, and synthetic fibers such as polyethylene terephthalate and nylon can be used by mixing them. Two or more types of the above-mentioned other fibers may be mixed as long as the heat formability is not impaired. As the blending ratio, for example, the polyester fiber used in the present invention can be blended preferably at 30% by mass or more, more preferably 50% by mass or more, and further preferably 70% by mass or more.

  The polyester fiber structure of the present invention preferably has a shrinkage rate of less than 1.5% in the atmosphere at a temperature of 130 ° C. and less than 2.0% in the horizontal direction. The shrinkage in an atmosphere at a temperature of 130 ° C. is more preferably less than 1.3% and less than 1.8% in width.

  The lower the shrinkage rate during heating, the smaller the dimensional change and the smaller the warp deformation after molding. On the other hand, when the shrinkage rate is 2.5% or more for both the warp and the width, warping and deformation after molding are large, making it difficult to use as a molding fabric.

  Since the polyester fiber structure of the present invention has a low tensile strength at high temperatures, it is possible to obtain a fabric that is easy to stretch during heat molding and has good moldability. At that time, the tensile strength retention is preferably 67% or less and 82% or less at a temperature of 130 ° C. The tensile strength retention is more preferably 65% or less and 65% in width, and further preferably 55% or less and 65% or less in width.

  Moreover, the polyester fiber used by this invention should just be partially used for the polyester fiber structure of this invention. For example, in the case of a nonwoven fabric, the polyester fiber used in the present invention and other known fibers can be mixed and used. Further, in the case of a long fiber processed yarn, the polyester fiber used in the present invention and a known fiber are false-twisted and then mixed into a mixed yarn, or in the case of long fiber knitted fabric, the present invention is applied to the front yarn. It is possible to use the polyester fiber used in the above and to use a known fiber for the back yarn and vice versa. Furthermore, if it is a tricot knitted fabric, the polyester fiber used in the present invention and a known fiber are alternately warped and knitted, and if it is a woven fabric, the polyester fiber used in the present invention is used for warp yarn. It is possible to use a known fiber for the weft and vice versa.

  Since the polyester fiber structure of the present invention has a low tensile strength when heated, the fabric is easily stretched during heat shaping, and good moldability can be obtained.

  The polyester fiber structure of the present invention can be suitably used for vehicle interior use and interior material use. In particular, the polyester fiber structure of the present invention is suitable for the field of heat molding, such as ceiling skins, floor carpets, luggage skins, rear parcels and seat backs for vehicle interior applications, and dust control mats and tile carpets for interior material applications. Can be used.

[Measuring method]
(1) Single fiber fineness JIS L 1015 (1999) 8.5.1 Based on the A method, the samples are drawn in parallel with a hammer and placed on the Rash paper placed on the cutting table. The gauge plate is crimped while being straightened, cut to a length of 30 mm with a blade such as a safety razor, and 300 fibers are counted as a set, and the mass is measured to determine the apparent fineness. From the apparent fineness and the equilibrium moisture content measured separately, the positive fineness (dtex) was calculated by the following formula, and the average value of 5 times was obtained.
F ₀ = D ′ × {(100 + R ₀ ) / (100 + R _e )}
F ₀ : Positive fineness (dtex)
D ': Apparent fineness (dtex)
R ₀ : Official moisture content (0.4)
R _e : equilibrium moisture content.

(2) Fiber length Based on JIS L 1015 (1999) 8.4.1 A method, a sample is drawn in parallel with a hammer and a staple diagram is formed to a width of about 25 cm with a pair type sorter. At the time of preparation, the number of times the fibers are grasped and pulled out to arrange all the fibers on the velvet plate is about 70 times. Place a celluloid plate with ticks on it and draw it on graph paper. The staple diagram illustrated in this way is equally divided into 50 fiber length groups, the boundaries of each segment and the fiber lengths at both ends are measured, 49 boundary fiber lengths are added to the average of the fiber lengths at both ends, and the result is divided by 50. The average fiber length (mm) was calculated.

(3) Strength and elongation Based on JIS L 1015 (1999) 8.7.1, the distance is 20 mm, the fibers are loosely stretched one by one on the parting line, and the ends are glued together with an adhesive and fixed. Each sample is one sample. Attach the sample to the grip of the tensile tester, cut the piece of paper near the upper grip, pull at a grip interval of 20 mm, and a tensile speed of 20 mm / min, and load (N) and elongation (mm) when the sample is cut. The tensile strength (cN / dtex) and the elongation (%) were calculated by measurement and the following formula.
T _b = SD / F ₀
T _b : Tensile strength (cN / dtex)
SD: Load at break (cN)
F ₀ : Positive fineness (dtex) of sample
S = {(E ₂ −E ₁ ) / (L + E ₁ )} × 100
S: Elongation rate (%)
E ₁ : Looseness (mm)
E ₂ : Elongation at cutting (mm) or Elongation at maximum load (mm)
L: Grasp interval (mm).

(4) Crimp number Based on JIS L 1015 (1999) 8.12.1, a dividing line is made by the same method as the strength and elongation of (3) above (however, the spatial distance is 25 mm). One sample taken from several parts where crimps are not impaired is provided with a looseness of 25 ± 5% with respect to the spatial distance, and both ends are adhered and fixed with an adhesive. Each sample is attached to the grip of the crimping tester one by one, the paper piece is cut, the distance between the grips when the initial load (0.18 mN x number of displayed tex) is applied to the sample (spatial distance) (mm ), The number of crimps at that time was counted, the number of crimps corresponding to 25 mm was obtained, and the average value of 20 times was obtained.

(5) Crimp degree Based on JIS L 1015 (1999) 8.12.2, the length when the initial load (0.18 mN x number of displayed tex) is applied to the sample, and the load (4.41 mN x displayed tex) The length when multiplying by (number) was measured and calculated by the following formula.
C _p = {(b−a) / b} × 100
C _p : Crimp degree (%)
a: Length when initial load is applied (mm)
b: 4.41 mN × length (mm) when multiplied by the number of texes.

(6) Dry heat shrinkage rate Based on JIS L 1015 (1999) 8.15, a dividing line was made by the same method as the strength and elongation of (3) above (however, the spatial distance was 25 mm), and the initial load was Read the distance (mm) when applied.

Remove the sample from the device, hang it in a dryer at a temperature of 150 ° C, leave it for 30 minutes, take it out, cool it to room temperature (20 ° C), reattach it to the device, and read the distance between the grips when the initial load is applied. The dry heat shrinkage was measured by the following formula.
S _d = {(L−L ′) / L} × 100
S _d : Dry heat shrinkage (%)
L: Distance between grips when the initial load before treatment is applied (mm)
L ′: Distance (mm) between grips when the initial load after treatment is applied.

(7) Tensile strength Based on JIS L 1913 (1999) 6.3.1, using an Instron type tensile tester, load until the test piece is cut under the conditions of a width of 30 mm, a grip interval of 150 mm, and a tensile speed of 200 mm / min. was added, the strength g ₀ at maximum load of the test piece was measured in 0.1N units were calculated from 5 times of the mean.

(8) Tensile strength and tensile strength retention in a high temperature atmosphere After leaving the test piece for 1 minute in an atmosphere at a temperature of 130 ° C., the tensile strength (g ₁ ) is the same as the tensile strength in (7) above. Was measured.

  Thereafter, the tensile strength retention was calculated from the tensile strength data of (7) using the following formula.

Tensile strength retention rate (%) = (g ₁ / g ₀ ) × 100
(9) based on the basis weight JIS L 1913 (1999) 6.2, the three test pieces 25 cm × 25 cm were taken, weighed mass (g) in each of the standard state by the following equation, the mass per 1 m ² (G / m < ² >) was calculated | required and the average value of the fabric weight was computed by following Formula.
S _m = W / A
S _m : basis weight (g / m ² )
W: Mass of test piece in standard state (g)
A: Area (m ² ) of the test piece.

(10) Shrinkage rate Based on JIS L 1906 (1999) 5.9.1, three 25 cm × 25 cm test pieces were sampled from the sample, and a mark representing the length of 20 cm in length and length was attached to the test piece. Using a constant temperature dryer, it was left in a tester at 130 ° C. for 3 minutes, taken out, and cooled to room temperature. Thereafter, the length of the vertical width was measured to 0.1 mm, and the shrinkage rate was calculated by the following formula.
ΔL = {(L−L ′) / L} × 100
ΔL: Shrinkage rate (%)
L: Total length of three lines of the test piece before heating (mm)
L ′: The total length (mm) of the three wires of the test piece after heating.

(11) Melting point (° C)
Maximum melting exothermic peak temperature when using a differential scanning calorimeter DSC-60, manufactured by Shimadzu Corporation, and heated to a temperature of 50 ° C. to 300 ° C. in a sample of 2 mg, nitrogen, at a heating rate of 10 ° C./min. Was the melting point (T _m ).

(12) Formability Using a 50 cm × 50 cm fabric, the back surface of the skin was heated to a temperature of 180 ° C. with a far-infrared heater, and then cold-pressed with a mold to evaluate the appearance of the molded product. According to the appearance evaluation, the transfer state of the mold is good, there is no deformation after molding, and the appearance is very good (◎), and there is no problem as a molded product (○). The case where the deformation was slightly seen was evaluated as (Δ), and the case where the skin was damaged or was broken and the deformation was seen was evaluated as bad (×). In the present invention, (◎) and (○) were accepted and (△) and (x) were rejected.

[Reference Example 1]
(spinning)
A polytrimethylene terephthalate resin having an intrinsic viscosity of 1.5 g / dl and a polyethylene terephthalate resin having an intrinsic viscosity of 0.5 g / dl are kneaded at a ratio shown in Table 1 using a biaxial vent type extruder, and a spinning temperature of 250 It was made to discharge at fibrous form at a temperature. The discharged fibrous polymer was cooled and solidified with a chimney wind, an oil solution was applied, and an undrawn yarn sub-tow was obtained at a roll rotation speed of 1000 m / min. A predetermined number (54) of the obtained sub-tow was bundled, drawn at a draw ratio of 3.0, and subjected to relaxation heat treatment at 140 ° C. for 20 minutes, then cut to a length of 51 mm, and the single fiber fineness was 6 Short fibers 1 to 4 having a fiber length of 51 mm were obtained at .6 dtex. Table 1 shows the physical properties of the obtained four types of short fibers 1 to 4.

[Reference Example 2]
(spinning)
A polytrimethylene terephthalate resin having an intrinsic viscosity of 1.5 g / dl and a polyethylene terephthalate resin having an intrinsic viscosity of 0.5 g / are prepared. The core polymer (PET) and the sheath polymer (PTT) are 240 ° C. and 270 ° C., respectively. It melted at a temperature, weighed with a pump, and flowed into a die at a temperature of 280 ° C. to perform core-sheath composite spinning to obtain an undrawn yarn subtow. A predetermined number (54) of the obtained sub-tows are bundled, stretched at a stretch ratio of 3.2 times, subjected to relaxation heat treatment at 140 ° C. for 20 minutes, cut to a length of 51 mm, and the single fiber fineness is 6. The short fiber 5 having a fiber length of 51 mm was obtained at 6 dtex. The physical properties of the obtained short fibers 5 are shown in Table 1.

[Reference Example 3]
(spinning)
A polytrimethylene terephthalate resin having an intrinsic viscosity of 1.5 g / dl was discharged in a fiber form at a spinning temperature of 250 ° C. The discharged fibrous polymer was cooled and solidified with a chimney wind, an oil solution was applied, and an undrawn yarn sub-tow was obtained at a roll rotation speed of 1000 m / min. A predetermined number (54) of the obtained sub-tow was bundled, drawn at a draw ratio of 3.0, and subjected to relaxation heat treatment at 140 ° C. for 20 minutes, then cut to a length of 51 mm, fineness of 6.6 dtex, fiber A short fiber 6 having a length of 51 mm was obtained. Table 1 shows the physical properties of the obtained short fibers 6.

[Reference Example 4]
(spinning)
A polyethylene terephthalate resin having an intrinsic viscosity of 0.5 g / dl was discharged in a fiber form at a spinning temperature of 280 ° C. The discharged fibrous polymer was cooled and solidified with a chimney wind, an oil solution was applied, and an undrawn yarn sub-tow was obtained at a roll rotation speed of 1000 m / min. A predetermined number (54) of the obtained sub-tow was bundled, drawn at a draw ratio of 3.0, and subjected to relaxation heat treatment at 140 ° C. for 20 minutes, then cut to a length of 51 mm, fineness of 6.6 dtex, fiber A short fiber 7 having a length of 51 mm was obtained. Table 1 shows the physical properties of the obtained short fibers 7.
[Reference Example 5]
(spinning)
A polytrimethylene terephthalate resin having an intrinsic viscosity of 1.5 g / dl and a polyethylene terephthalate resin having an intrinsic viscosity of 0.5 g / dl are kneaded at a ratio shown in Table 1 using a biaxial vent type extruder, and a spinning temperature of 250 It was made to discharge at fibrous form at a temperature. The discharged fibrous polymer was cooled and solidified with a chimney wind, an oil solution was applied, and an undrawn yarn sub-tow was obtained at a roll rotation speed of 1000 m / min. The obtained sub-tow was bundled into a predetermined number (54), drawn at a draw ratio of 3.3 times, subjected to relaxation heat treatment at 140 ° C. for 20 minutes, cut to a length of 51 mm, and the single fiber fineness was 3 The short fiber 8 having a fiber length of 51 mm was obtained at 3 dtex. Table 1 shows the physical properties of the four types of short fibers 8 obtained.

[Reference Example 6]
(spinning)
A polyethylene terephthalate resin having an intrinsic viscosity of 0.5 g / dl was discharged in a fiber form at a spinning temperature of 280 ° C. The discharged fibrous polymer was cooled and solidified with a chimney wind, an oil solution was applied, and an undrawn yarn sub-tow was obtained at a roll rotation speed of 1000 m / min. The obtained sub-tow was bundled into a predetermined number (54), drawn at a draw ratio of 3.3 times, subjected to relaxation heat treatment at 140 ° C. for 20 minutes, cut to a length of 51 mm, a fineness of 3.3 dtex, fiber A short fiber 9 having a length of 51 mm was obtained. The physical properties of the obtained short fibers 9 are shown in Table 1.

[Examples 1-4, Comparative Examples 1-3]
(Nonwoven fabric)
The fine fibers of 6.6 dtex obtained in Reference Examples 1 to 4 and short fibers 1 to 7 having a fiber length of 51 mm were each opened and then supplied to a roller card to obtain seven types of webs. Subsequently, the obtained web was driven by a needle punch machine with a needle No. 36 at a needle depth of 15 mm and a density of 320 needles / cm ² to obtain a needle punch nonwoven fabric having a basis weight of 327 to 364 g / m ^2. It was. Table 2 shows the physical properties of the obtained seven needle punched nonwoven fabrics.

  The nonwoven fabrics of Examples 1 to 4 had a low shrinkage rate, a low tensile strength at high temperatures, and were extremely excellent in moldability. Although the nonwoven fabric of Comparative Example 1 had a low shrinkage rate, the tensile strength at high temperatures was slightly high, and the moldability was slightly poor. In the nonwoven fabric of Comparative Example 2, the number of crimps and the degree of crimping of the short fibers were low, and in the carding process, cotton falling and nipping were likely to occur, and the appearance quality of the nonwoven fabric was also poor. Moreover, although the tensile strength at high temperature was reduced, the shrinkage rate was as high as 3% or more, and warping occurred after molding, resulting in poor moldability. Although the nonwoven fabric of Comparative Example 3 had a low shrinkage rate, the tensile strength at high temperatures was high, and the fabric was difficult to stretch at the time of molding, and the moldability was somewhat poor. The results are shown in Table 2.

[Examples 5 to 8]
The short fiber 2 and the short fiber 7 were blended at the blending ratio shown in Table 3 and supplied to a roller card to obtain a web. Subsequently, the obtained web was driven with a needle punch machine using a 36th needle at a needle depth of 15 mm and a density of 320 needles / cm ² to obtain a needle punch nonwoven fabric having a basis weight of 320 to 335 g / m ^2. It was. Table 3 shows the physical properties of the obtained nonwoven fabric.

  The nonwoven fabrics of Examples 5 to 8 had low shrinkage, low tensile strength at high temperatures, and excellent moldability.

[Example 9]
A PTT resin with an intrinsic viscosity of 1.5 g / dl is supplied to a melt spinning machine at a ratio of 40 mass% and PET resin with an intrinsic viscosity of 0.5 g / dl is fed to a melt spinning machine and discharged into a fiber at a spinning temperature of 280 ° C. It was. The discharged fibrous polymer was cooled and solidified with a chimney wind, an oil solution was applied, and the roll was drawn at a roll rotation speed of 1600 m / min and a roll temperature of 55 ° C. Subsequently, without winding the yarn, the film was stretched at a roll rotation speed of 4200 m / min and a roll temperature of 150 ° C., and subsequently subjected to a relaxing heat treatment at a roll rotation speed of 3990 m / min and a roll temperature of 150 ° C. A fiber yarn having a total fineness of 84 dtex was obtained. The melting point of the obtained fiber was 216 ° C.

(Manufacturing)
Using the above-mentioned fiber yarn, using a 28-gauge tricot warp knitting machine, the front yarn has a wrinkle structure 2-3 / 1-0 and the back yarn has two wrinkle structures 1-2 / 1. A warp knitted fabric was knitted with an on-machine course density of -0 and 65 courses / 2.54 cm. The resulting warp knitted fabric is dyed at a temperature of 130 ° C. for 30 minutes using a liquid dyeing machine, washed with hot water at 80 ° C. for 20 minutes twice, and then the front yarn side of the knitted fabric is knitted. Raising with a raising machine, finishing setting was performed at 160 ° C. for 1 minute, and a raised warp knitted fabric with a basis weight of 280 g / m ² was obtained. The obtained warp knitted fabric has a tensile strength of 89.6 N / cm and a width of 98.6 N / cm, and a tensile strength at a high temperature of 43.9 N / cm and a width of 60.1 / cm. The strength retention was 49% vertical and 61% horizontal. The shrinkage was 1.01% in the vertical direction and 1.09% in the horizontal direction, the melting point peak was 216 ° C., and the moldability was “外 観” in appearance. The results are shown in Table 4.

[Example 10, Comparative Example 5]
The short fiber 8 and a polyethylene terephthalate fiber (short fiber 9) having a fineness of 3.3 dtex and a fiber length of 51 mm obtained by a known method were opened and then supplied to a roller card to obtain a web. Subsequently, the obtained web was driven with a needle punch machine with a needle No. 40 at a needle depth of 15 mm and a density of 420 needles / cm ² to obtain a needle punched nonwoven fabric having a basis weight of 172 to 186 g / m ² . . Table 5 shows the physical properties of the obtained nonwoven fabric. The nonwoven fabric of Example 9 had a low shrinkage rate, a low tensile strength at high temperatures, and was extremely excellent in moldability. The nonwoven fabric of Comparative Example 5 had high tensile strength at high temperatures and was slightly poor in moldability.
[Examples 10 to 12, Comparative Example 6]
Short fibers 8 and polyethylene terephthalate fibers (short fibers 9) were blended at the blending ratio shown in Table 4 and supplied to a roller card to obtain a web. Subsequently, the obtained web was driven with a needle punching machine at a needle depth of 15 mm and a density of 420 needles / cm ^{2 with} a needle No. 40 to obtain a needle punched nonwoven fabric having a basis weight of 172 to 189 g / m ² . . Table 4 shows the physical properties of the obtained nonwoven fabric. The nonwoven fabrics of Examples 10 to 12 were excellent in texture, low in tensile strength at high temperatures, and excellent in moldability. On the other hand, the nonwoven fabric of Comparative Example 6 had slightly high tensile strength at high temperatures, and the moldability was slightly poor.

Claims (3)

  A fiber structure using a polyester fiber formed by kneading 5 to 95% by mass of a polytrimethylene terephthalate resin and 95 to 5% by mass of a polyethylene terephthalate resin, wherein the fiber has a melting point peak of 210 to 220 ° C. A polyester fiber structure characterized by having one peak of   The polyester fiber structure according to claim 1, wherein the polyester fiber structure has a tensile strength retention at a temperature of 130 ° C. of 67% or less and a width of 82% or less.   The polyester fiber structure according to claim 1 or 2, wherein the polyester fiber structure is a needle punched nonwoven fabric.