JP2007270392A - Crimped yarn for aliphatic polyester carpet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide crimped yarn for a carpet, which is composed of an aliphatic polyester and having improved hydrolysis resistance, reduced crimp loss, and excellent durability. <P>SOLUTION: This crimped yarn for aliphatic polyester carpet comprises an aliphatic polyester and at least difunctional epoxy-based terminal-blocking agent, wherein a COOH terminal groups of the aliphatic polyester at least partially reacts with the epoxy-based terminal-blocking agent. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a crimped yarn for carpet made of an aliphatic polyester excellent in durability, in which hydrolysis resistance and settling of crimps are suppressed.

  Polyesters represented by polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polylactic acid, polycaprolactone, polybutylene succinate, etc. are excellent in mechanical properties and chemical properties, Depending on the properties of each polyester, they are used for textiles and industrial materials, for example. In the case of PET, an aromatic polyester mainly composed of aromatic dicarboxylic acid and alkylene glycol, which is a typical polyester, for example, PET, bis (2- Hydroxyethyl) terephthalate is produced and industrially produced, for example, by a polycondensation method in which this is polycondensed using a catalyst at high temperature and under vacuum. On the other hand, polylactic acid contained in aliphatic polyester is produced by ring-opening polymerization of lactide or direct polymerization of lactic acid.

  Among these, aliphatic polyesters have poor mechanical strength and thermal properties compared to aromatic polyesters, but they considered global environmental issues such as excellent flexibility and transparency and the raw materials are plants. In particular, there are characteristics that are not found in aromatic polyesters, and applications are currently being developed in various fields.

  However, aliphatic polyesters generally have a high hydrolysis rate and easily decrease in molecular weight, so that it is difficult to maintain the mechanical strength of the molded product. This tendency was remarkable under conditions of high heat and humidity, which was an obstacle to commercialization. In particular, in the field of fibers, it has been found that the specific surface area is higher than that of other molded products, so that it is susceptible to the hydrolysis.

  Therefore, for example, Patent Document 1 describes a technique for substituting the acid terminal or alcohol terminal of an aliphatic polyester with another compound to suppress hydrolysis. The technique described in this document describes that a carbodiimide compound or an epoxy compound is used as a terminal blocking agent. However, it is difficult to suppress the settling of crimps in the hot water treatment process (dyeing, heat setting, etc.) of the crimped yarn for carpet only by simply improving the hydrolysis resistance.

On the other hand, Patent Document 2 discloses a method for adding such end-capping compounds with few problems. Since the compound described in Patent Document 2 is trifunctional, it is described that the gas barrier property is improved by increasing the viscosity at the time of melt molding even at a low draw ratio. However, Patent Document 2 relates to a film, and the fiber has not been studied.
Japanese Patent Laid-Open No. 08-120520 (page 3, paragraph 0014) JP 2005-314444 A (page 2)

  An object of the present invention is to provide a crimped yarn for carpet made of an aliphatic polyester excellent in durability, in which hydrolysis resistance and settling of crimp are suppressed.

  That is, the present invention is an aliphatic polyester carpet composed of a bifunctional or higher functional epoxy-based endblocker and an aliphatic polyester, wherein the epoxy-based endblocker is at least partially reacted with the COOH end group of the aliphatic polyester. The above-mentioned problem can be solved by the crimped yarn.

  The aliphatic polyester used in the present invention is obtained by polycondensation of saturated dicarboxylic acid and diol, or is obtained by polycondensation of hydroxycarboxylic acid. Examples of aliphatic polyesters obtained by polycondensation include polylactic acid, polyglycolic acid, poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-3hydroxyvalerate) copolymer, polycaprolactone, Polypivalolactone, or a polyester composed of glycol such as ethylene glycol or 1,4-butanediol and dicarboxylic acid such as succinic acid or adipic acid may be used.

  Although these aliphatic polyesters have the disadvantage that they hydrolyze faster than aromatic polyesters, they are easily derived from natural products, and are generally more flexible than aromatic polyesters. It is preferable to use an aliphatic polyester. Of these aliphatic polyesters, polylactic acid is superior to other aliphatic polyesters in terms of mechanical properties and heat resistance, and is particularly preferably used.

  In addition, two types of polylactic acid that are particularly preferably used in the present invention are known, one mainly composed of L-lactic acid and one mainly composed of D-lactic acid. Although the optical purity of lactic acid in polylactic acid is 97% or more, the melting point of the resin can be increased, that is, it is preferable because of excellent heat resistance. In general, the polylactic acid particularly preferably used in the present invention has a crystallinity that decreases when the optical purity is lowered. Therefore, the obtained crimped yarn for aliphatic polyester carpet generally has a low heat resistance and is practical. A crimped yarn for aliphatic polyester carpet cannot be obtained. For this reason, polylactic acid having an optical purity of 98% or more is preferably used. When the optical purity in one polymer molecule satisfies the above value, for example, polylactic acid obtained by melt-mixing a polymer mainly composed of L-lactic acid and a polymer mainly composed of D-lactic acid can be used. In this case, the polylactic acid molecular chain mainly composed of L-lactic acid and the polylactic acid molecular chain mainly composed of D-lactic acid form a stereocomplex crystal, and the crystal has a higher melting point than the homopolymer. Therefore, it is preferable because the crimped yarn for aliphatic polyester carpet is excellent in heat resistance. In addition, the fiber to which the epoxy compound of the present invention is added has good wet heat aging characteristics, and the crimped yarn for aliphatic polyester carpet having high heat resistance is deteriorated in strength even when the crimping treatment is performed with high-temperature steam. Therefore, it is possible to obtain a highly crimped and excellent quality, which is preferable.

  The polylactic acid preferably has a weight average molecular weight of 100,000 or more from the viewpoints of heat resistance and yarn production. By setting the weight average molecular weight to 100,000 or more, the crystallinity of the resulting crimped yarn for an aliphatic polyester carpet is increased, the durability is improved, and not only a crimp is reduced but also melted. The fluidity and crystallization characteristics at the time can also be set within a preferable range, and stable production becomes possible. Accordingly, the weight average molecular weight is more preferably in the range of 100,000 to 400,000, and most preferably in the range of 120,000 to 250,000.

  The amount of unreacted monomers and oligomers contained in the polylactic acid particularly preferably used in the present invention is preferably in the range of 0.01 to 0.3% by weight. Unreacted monomers and oligomers may bleed during melt molding and contaminate the device, or react with the epoxy compound of the present invention to reduce the activity of the epoxy compound, but if there is a very small amount, It acts as a so-called plasticizer and can improve moldability. Therefore, the amount of the monomer and oligomer is preferably in the range of 0.01 to 0.2% by weight, and more preferably in the range of 0.01 to 0.15% by weight.

  The aliphatic polyester used in the present invention may contain other modifiers, additives and other polymers as long as the characteristics are not changed. These modifiers, additives and other polymers may be added at the time of polymerization, may be in the form of master pellets previously kneaded, or may be directly mixed with aliphatic polyester pellets and melt molded. Furthermore, it is also preferable to add another monomer and copolymerize in such a range that the basic characteristics of the aliphatic polyester are not largely changed. The monomer to be copolymerized is not particularly limited, and dicarboxylic acid, alkylene glycol, or the like that is copolymerized with an aliphatic polyester and does not decrease the molecular weight is preferably used. The blending amount of the copolymer component is preferably 40 mol% or less with respect to the aliphatic polyester, since a desired modification effect can be obtained without largely changing the basic characteristics of the aliphatic polyester.

  In the crimped yarn of the present invention, it is important to react a bifunctional or higher functional epoxy compound with the end of the aliphatic polyester. In particular, it is important that the bifunctional or higher functional epoxy compound has two or more epoxy groups in one compound molecule. If there are two or more epoxy groups for one molecule of the compound, melt kneading with the aliphatic polyester, and when the crimped yarn for carpet of the present invention is obtained, a part of it reacts with the aliphatic polyester to increase the molecular weight. By doing so, it becomes possible to suppress the settling of crimps and to improve wet heat aging characteristics.

  The bifunctional or higher functional epoxy compound of the present invention is characterized by having at least one glycidyloxycarbonyl group or N- (glycidyl) amide group in one molecule. Preferably, it is preferable to have at least one structure of the following formula (I) or (II) in one molecule.

(In the formula, R1 represents a functional group having a hydrocarbon skeleton containing a saturated bond / unsaturated bond / substituent or a functional group containing a saturated bond / unsaturated bond / substituent containing a covalent bond atom other than carbon. R2 represents a functional group having a hydrocarbon skeleton containing a saturated bond / unsaturated bond / substituent or a functional group containing a saturated bond / unsaturated bond / substituent containing a covalent bond atom other than carbon, and R1 In the formula, 1 to 3 are attached for the sake of explanation of the reactivity of the glycidyl group.)

  It is preferable to have at least one structure of the above formula (I) or (II) in one molecule. As a result of examining various compounds with respect to the epoxy compound having the structure of the above formula (I) or (II), it was found that the epoxy compound having the structure is specifically highly reactive. The cause of this is not clear, but it is thought as follows. The oxygen of the carbonyl group has a high electron density, and this mainly takes the form of attacking 1 carbon in the formula of the glycidyl group. As a result, it can take a pseudo 6-membered ring structure in which the epoxy ring is opened. That is, it is considered that the energy required for ring opening of the epoxy ring is lower than that of the compound not having the pseudo 6-membered ring structure, and thus the reactivity is specifically high. Therefore, in the present invention, it is preferable to use a compound having at least one structure of the above formula (I) or (II) in one molecule as a bifunctional or higher functional epoxy compound.

  Moreover, as a specific example of the compound which can take this pseudo 6-membered ring structure, the compound of Formula (I) is 7,8-dimethyl-1,7,8,14-tetradecane tetracarboxylic acid tetrakis (oxiranyl). Methyl), 7-oxabicyclo [4.1.0] heptane-3,4-dicarboxylate diglycidyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid] ethylene, bis [ 2- (Glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid] 1,3-propanediyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid] 1 , 4-Butanediyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid 1,5-pentanediyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid] 1,6-hexanediyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy -1-cyclohexanecarboxylic acid] 1,7-heptanediyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid] 1,8-octanediyl, bis [2- (glycidyloxycarbonyl) ) -4,5-epoxy-1-cyclohexanecarboxylic acid] 1,9-nonanediyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid] 1,10-decanediyl, bis [ 2- (Glycidyloxycarbonyl) -4,5-epoxy-1-cyclohe Suncarboxylic acid] 1,11-undecanediyl, bis [2- (glycidyloxycarbonyl) -4,5-epoxy-1-cyclohexanecarboxylic acid] 1,12-dodecanediyl, 4-cyclohexene-1,2-dicarboxylic acid bis (Oxiran-2-ylmethyl), 4,4-bis [4- (2,3-epoxypropan-1-yloxy) phenyl] pentanoic acid 2,3-epoxypropan-1-yl, 4,4-bis [4 -(2,3-epoxypropan-1-yloxy) phenyl] pentanoic acid 2,3-epoxypropan-1-yl group, oxalic acid diglycidyl ester, malonic acid diglycidyl ester, succinic acid diglycidyl ester, glutar Acid diglycidyl ester, adipic acid diglycidyl ester, pimelic acid diglycidyl ester, Dicarboxylic acid diglycidyl ester groups such as octanedioic acid diglycidyl ester, nonanedioic acid diglycidyl ester, decanedioic acid diglycidyl ester, terephthalic acid diglycidyl ester, 1,6-naphthalenedicarboxylic acid diglycidyl ester, mono (substituted) -Or unsubstituted-) phenyl diglycidyl isocyanurate, mono (substituted-or unsubstituted-) aralkyl diglycidyl isocyanurate, mono (substituted-or unsubstituted-) naphthyl diglycidyl isocyanurate, mono (substituted-or unsubstituted-) There are isocyanuric acid modifications such as) naphthyl alkyl diglycidyl isocyanurate, mono (substituted- or unsubstituted-) alkyl diglycidyl isocyanurate, mono (substituted- or unsubstituted-) allyl diglycidyl isocyanurate, As monobenzyl diglycidyl isocyanurate, monophenyl diglycidyl isocyanurate, mononaphthyl diglycidyl isocyanurate, mononaphthyl methyl diglycidyl isocyanurate, monobenzyl di (methyl glycidyl) isocyanurate, monophenyl di (methyl glycidyl) isocyanurate, mononaphthyl di ( Methyl glycidyl) isocyanurate, mononaphthylmethyl di (methyl glycidyl) isocyanurate, monomethyl diglycidyl isocyanurate, monoethyl diglycidyl isocyanurate, monopropyl diglycidyl isocyanurate, monobutyl diglycidyl isocyanurate, monoallyl diglycidyl isocyanurate Mono (2,3-hydroxy) propyl diglycidyl isocyanurate, Examples include groups such as liglycidyl isocyanurate. In addition to selecting at least one monomer selected from the above groups, glycidyl acrylate, glycidyl methacrylate, norborna-2,5-diene-2,3-dicarboxylic acid Acid 2-methyl 3-glycidyl, 2-phenylnorborna-2,5-diene-3-carboxylate glycidyl, 2- (piperidinocarbonyl) norborna-2,5-diene-3-carboxylate glycidyl, 2- (Dipropylcarbamoyl) norborna-2,5-diene-3-carboxylate glycidyl, 2-methylenebutanoate (2-ethyloxylan-2-yl) methyl, 3-pentenoate glycidyl, 4-pentenoate glycidyl, 5- Glycidyl hexenoate, glycidyl 6-heptenoate, glycidyl 7-octenoate, glycone 8-nonenate Examples include a polymer obtained by polymerizing a monomer containing at least one kind of sidyl or a modified product thereof.

  In the case where a monomer is used as the bifunctional or higher epoxy compound of the present invention, when considering the heat resistance and the reaction efficiency due to the epoxy index, 7,8-dimethyl-1,7,8,14-tetradecane is used. Tetracarboxylic acid tetrakis (oxiranylmethyl), 7-oxabicyclo [4.1.0] heptane-3,4-dicarboxylic acid diglycidyl, terephthalic acid diglycidyl ester, and triglycidyl isocyanurate are preferable, and triglycidyl isocyanurate is more preferable. Is preferably used. Triglycidyl isocyanurate is a powder having a melting point of about 100 ° C. and is easy to handle, and when it is melt-mixed with the aliphatic polyester of the present invention using, for example, a twin screw extruder, the triglycidyl isocyanurate is melted. Thus, a finely dispersed structure in the aliphatic polyester can be obtained. By making the aliphatic polyester the above-mentioned structure, it is possible not only to reduce melt viscosity and molecular weight spots of the resin, it is possible to stably produce the crimped yarn for aliphatic polyester carpet of the present invention, It is possible to obtain a crimped yarn having excellent quality by suppressing unevenness of the obtained crimped yarn for an aliphatic polyester carpet, and having little variation in strength and crimping properties.

  Moreover, when using a polymer among the above as an epoxy compound more than bifunctional of this invention, considering the reactivity and compatibility with aliphatic polyester, glycidyl acrylate, glycidyl methacrylate, norborna-2,5-diene 2-methyl 3-glycidyl 2,3-dicarboxylate, 2-phenylnorborna-2,5-diene-3-glycidyl 2-carboxylate, 2- (piperidinocarbonyl) norborna-2,5-diene-3- Glycidyl carboxylate, 2- (dipropylcarbamoyl) norborna-2,5-diene-3-carboxylate, glycidyl 2-methylenebutanoate (2-ethyloxylan-2-yl) methyl, glycidyl 3-pentenoate, 4- Glycidyl pentenoate, glycidyl 5-hexenoate, glycidyl 6-heptenoate, glycidyl 7-octenoate , It is preferable to use a polymer containing at least one monomer comprising at least one of 8-nonenoic acid glycidyl and these modified products. Moreover, what adjusted the compatibility and reactivity with aliphatic polyester and copolymerized monomers other than the said monomer are used suitably. The copolymer component is not particularly limited as long as it has a carbon-carbon double bond and can be polymerized with the above monomer. For example, ethylene, propene, 2-butene, 1,3-butadiene, Styrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, 2-methylpropene, isoprene, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate , N-pentyl acrylate, n-hexyl acrylate, phenyl acrylate, benzyl acrylate, naphthyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t -Butyl, n-pentyl methacrylate, n-hexyl methacrylate, methacrylate Acid phenyl, benzyl methacrylate, and the like methacrylic acid-naphthyl and these modified products.

  Among these copolymerizable components, ethylene, propene, 2-butene, 1, are considered in consideration of reactivity with the above reactive monomer and compatibility with aliphatic polyester, and availability. 3-butadiene, styrene, isoprene, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, t-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, methacrylic acid , Methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, ethylene, styrene, isoprene, acrylic acid Methyl, ethyl acrylate, propyl acrylate, n-butyl acrylate, acrylic acid t Butyl, n-pentyl acrylate, n-hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, n-pentyl methacrylate, n-to methacrylate Xylyl and modified products thereof are more preferably used. In particular, when polylactic acid that is suitably used in the present invention is used among aliphatic polyesters, a structure having acrylic acid or methacrylic acid as a skeleton should have a structure excellent in compatibility with polylactic acid. It is more preferable because it can be uniformly added and reacted in the resin.

  The composition of the monomer that is a copolymerization component with respect to the reactive monomer can be arbitrarily determined, but the epoxy index of the epoxy compound, compatibility with the aliphatic polyester, thermal and physical properties Etc. are appropriately determined according to the purpose. The epoxy index of the monomer or polymer epoxy compound is preferably in the range of 500 to 15000 equivalent / t. By adding a bifunctional or higher functional epoxy compound having an epoxy index within the above range to the crimped yarn for aliphatic polyester carpet of the present invention, the aliphatic polyester partially reacts, and there is a problem of thickening or gelation. It becomes possible to manufacture a product that is not present stably. In general, in melt spinning, when the thickening occurs, the yarn production stability tends to be impaired and the yield tends to deteriorate, but if the compound has an epoxy index in the above range, there is no problem as described above, and the effect of the present invention, That is, when the crimped yarn for an aliphatic polyester carpet is melt-molded again, the remaining epoxy group reacts with the end of the aliphatic polyester, whereby the weight average molecular weight is increased and the settling of the crimp can be suppressed. From this, the epoxy index is preferably within the above range in order to achieve the effects of the present invention and to perform stable spinning, and the above range is more preferably 1000 to 12000 equivalents / t, more preferably 3000 to 12000 equivalents / t. Most preferably in the range of t.

  The bifunctional or higher functional epoxy compound of the present invention is preferably added in the range of 0.3 to 3.0% by weight. If the addition amount of the epoxy compound is 0.3% by weight or more, it is possible to sufficiently suppress the settling of the crimp due to the increase in the molecular weight of the present invention. In addition, if the amount of the epoxy compound added is 3.0% by weight or less, in addition to obtaining the effect of increasing the molecular weight, it is possible to avoid an increase in cost due to the compound, and further prevent environmental deterioration due to scattering during production. Thus, stable production becomes possible. For these reasons, the addition amount of the epoxy compound is more preferably in the range of 0.7 to 2.0% by weight.

  Further, the crimped yarn for aliphatic polyester carpet of the present invention preferably has a COOH end group concentration of the aliphatic polyester of 20 equivalent / t or less due to the effect of addition of the epoxy compound. In general, polyester fibers are likely to decrease in molecular weight due to hydrolysis when the COOH end group concentration is high, and the strength and toughness of the polyester fibers are reduced during long-term storage and transportation by sea exposed to high temperature and humidity. There is a problem. By setting the COOH end group concentration in the crimped yarn for aliphatic polyester carpet of the present invention within the above range, it becomes possible to suppress the deterioration of the fiber due to hydrolysis, and further the hot water treatment in the carpet manufacturing process. Therefore, it is possible to obtain a crimped yarn for an aliphatic polyester carpet having excellent quality. The lower the COOH end group concentration, the higher the effect described above, and thus the more preferable, the concentration is more preferably 15 equivalents / t or less, and even more preferably 10 equivalents / t or less. Most preferably not.

  Further, when the strength of the crimped yarn for aliphatic polyester carpet of the present invention is in the range of 0.8 to 3 cN / dtex, the yarn dyeing process and the passing process of the twisting process are prevented, and yarn breakage during tufting is prevented. It is possible to obtain a carpet with excellent quality, which is preferable. Therefore, a more preferable range of strength is 1 to 3 cN / dtex.

  Further, when the crimp elongation rate of the crimped yarn for aliphatic polyester carpet of the present invention is in the range of 3 to 18%, a carpet having excellent volume feeling can be obtained because of excellent bulkiness when used as a carpet. Moreover, since it is not necessary to perform an excessive heat treatment at the time of crimping, a crimped yarn having excellent fiber strength can be obtained, which is preferable. For this reason, the crimp elongation rate is more preferably in the range of 5 to 15%.

  The polylactic acid crimped yarn in the present invention preferably has a total fineness of 600 to 2500 dtex. If the total fineness is 600 dtex or more, when tufting as a carpet pile, stable tufting is possible as a practical basis weight, and a carpet with excellent quality can be obtained. Even if twisted yarns are used as cut piles of various twisted yarns, they can be produced without greatly changing gauges and stitches to mass-produced products, and a carpet with excellent volume can be obtained at low cost. In addition, by setting the total fineness to 2500 dtex or less, it becomes possible to smoothly cool the yarn in the yarn making process, and it is possible to obtain a crimped yarn having no processability and excellent in process passability. For these reasons, the total fineness is more preferably in the range of 800 to 2000 dtex.

  The crimped yarn for an aliphatic polyester carpet in the present invention is a multifilament yarn that is given a three-dimensional random spiral shape by heating fluid treatment or the like and is given excellent bulkiness as a surface yarn of a carpet or the like. The three-dimensional random spiral shape means that the constituent single yarn of the crimped yarn for aliphatic polyester carpet has a shape in which at least a part is swollen in the fiber diameter direction by heating fluid treatment or the like, and has this structure. Thus, the crimped yarn for aliphatic polyester carpet of the present invention can have desired bulkiness, stretchability, and bulkiness.

  That is, the crimped yarn for an aliphatic polyester carpet of the present invention refers to a yarn having a bulkiness by imparting a three-dimensional crimp to a multifilament. This makes it possible to develop a bulky property when used as a surface yarn of a carpet or the like. The crimp with respect to a multifilament can be provided by a well-known method without a restriction | limiting especially. Examples thereof include mechanical crimping with gears, crimping by asymmetric heat treatment during spinning, false twisting method, crimping by heating fluid treatment, and the like. Among these, it is preferable to apply the heating fluid such as heated air or steam from the viewpoint of imparting a three-dimensional random crimp and the ability to impart a high crimp. A method using a heating fluid is particularly preferable because it can provide crimps with less damage to the yarns, and thus can obtain crimped yarns with high tensile strength.

  In the present invention, in order to obtain a carpet having a soft and soft texture, it is preferable that the fineness of the single yarn constituting the crimped yarn for aliphatic polyester carpet is in the range of 5 to 30 dtex. In general, in the case of filaments made of aliphatic polyester, the smaller the fineness of the single yarn, the more likely to cause single yarn breakage in the filament spinning process, and to obtain crimps particularly suitable for surface yarns such as carpets. In such a case, it is necessary to draw at a high draw ratio immediately before passing through a crimping process such as fluid crimping treatment. Not only yarn breakage occurs during the crimping process such as the crimping process, but fibrillation easily occurs during use as a carpet or the like. However, by setting the single yarn fineness to 5 dtex or more, the above-described problems do not occur, and further, the occurrence of pilling when the carpet is made can be suppressed, and the aliphatic polyester carpet has high crimp and excellent processability. It is preferable because a crimped yarn can be obtained. Further, by setting the fineness of the single yarn constituting the crimped yarn for aliphatic polyester carpet of the present invention to 30 dtex or less, the flexibility of the obtained crimped yarn for aliphatic polyester carpet is maintained, and the texture of the resulting carpet is improved. Further, since the cooling in the yarn production process can be made uniform easily, a crimped yarn for an aliphatic polyester carpet excellent in process stability can be obtained.

  The cross-sectional shape of the crimped yarn for aliphatic polyester carpet of the present invention is not particularly limited, but in order to obtain a crimped yarn for aliphatic polyester carpet excellent in process stability without thread breakage or the like, The cross-sectional shape of the fiber is preferably a round cross section. In order to improve the bulkiness and covering properties of the carpet, modified cross-section fibers such as a trilobal cross section, a hollow cross section, and a flat cross section are also suitable.

  In the case of a trilobal cross section, the inscribed circle diameter (A) and circumscribed circle diameter of the trilobal cross section measured from the cross-sectional photograph, when trying to achieve both process stability, covering properties, and bulkiness The degree of cross-sectional deformation calculated from the ratio (B ÷ A) of (B) is preferably in the range of 1.5 to 5.5. If the degree of cross-sectional deformation is in the above range, it is possible to achieve both sufficient process passability, covering ability, and bulkiness, and further to obtain a glossy carpet by reflecting light on the fiber surface. it can.

  Moreover, in the case of a hollow cross section, the hollow ratio measured from the cross-sectional photograph is preferably in the range of 5 to 50%. If the hollow ratio is 5% or more, it is possible to obtain a crimped yarn for an aliphatic polyester carpet having excellent bulkiness, and if the hollow ratio is 50% or less, it is possible to prevent abnormalities due to crushing of the hollow portion. Therefore, it is possible to achieve both sufficient process passability, covering ability and bulkiness, and excellent quality when used as a carpet. For these reasons, the hollowness ratio is more preferably in the range of 10 to 30%. Further, the shape and number of the hollow portions of the hollow cross section are not particularly defined, but the shape is preferably a round cross section from the viewpoint of difficulty in collapsing the hollow portion. Further, when used as a cut pile, it is suitable because it has a hollow cross section so that it does not stand out even if dirt is attached.

  In the case of a flat cross section, the flatness (C ÷ D) calculated from the major axis (C) and the minor axis (D) measured from the cross-sectional photograph is preferably in the range of 2-6. If the flatness is 2 or more, the flexibility of the crimped yarn can be sufficiently improved, and the covering property can also be improved. Further, if the flatness is 6 or less, the process can be easily passed and the rigidity of the yarn can be secured, so that a carpet having an excellent texture can be obtained. Therefore, the flatness is more preferably in the range of 3-5. Moreover, what has one or more convex parts is used suitably for the cross section of the crimped yarn for aliphatic polyester carpets which has the said flat cross section.

  Next, an example of a preferred method for producing the polylactic acid crimped yarn of the present invention will be described.

  First, an aliphatic polyester chip and a bifunctional or higher functional epoxy compound are separately weighed and supplied to an extruder, followed by filtration in a spin pack and spinning from a spinneret. At this time, it is also preferable to supply the bifunctional or higher functional epoxy compound as a master pellet to which a high concentration is added in advance. The spun yarn is cooled and solidified by cold air, and then an oil agent is adhered. As the oil agent, a known oil agent can be used, and it is desirable to use an appropriate oil agent that controls the friction coefficient of the fiber according to the application. Thereafter, the yarn is taken up by a take-up roll and then hot drawn. As preferable conditions for simultaneously satisfying the preferable ranges of the tensile strength and crimp elongation of the present invention, it is preferable to adopt a take-up speed of 400 to 2000 m / min and a draw ratio of 2 to 5 times. In order to suppress fluff and single yarn breakage, it is more preferable that the orientation is advanced to some extent before the take-up and finally the stretch is performed about 3 times.

  In order to perform sufficient preheating during drawing and suppress devitrification and deterioration of physical properties of the yarn, it is a preferable method to use a Nelson roller. Then, it introduce | transduces into a heating fluid crimp provision apparatus, and a crimp is provided. Heated steam or heated air is preferably used as the heating fluid for imparting crimps. Usually, the temperature of the heating fluid applied to the yarn is preferably 130 ° C to 200 ° C. If the temperature of the heating fluid is 130 ° C. or higher, a highly crimped crimped yarn for an aliphatic polyester carpet can be obtained, and if it is 200 ° C. or lower, the fusion of single yarns can be suppressed. It is possible to prevent a decrease in strength. The heating medium is more preferably heated air than heated steam from the viewpoint of reducing damage due to hydrolysis of the aliphatic polyester.

  However, the crimped yarn for aliphatic polyester carpet according to the present invention has an epoxy compound added thereto and has improved resistance to moist heat aging, so that heated steam can be used as the heating fluid. In this case, the temperature of the heating steam is preferably 130 to 170 ° C. from the viewpoint of imparting crimps and suppressing hydrolysis.

  After the crimped yarn is cooled, it is stretched to such an extent that the crimp does not sag, and is finally wound on a package. The crimped yarn for aliphatic polyester carpet of the present invention usually employs a winding tension of 0.1 cN / dtex or less. By setting the winding tension to 0.1 cN / dtex or less, the package shape of the winding yarn can be brought into a suitable state, and the strength is lowered with time and the strength at the end face is decreased. It is possible to prevent the crimps from becoming loose due to the change. The above production method may be performed by winding the yarn once in an arbitrary part of the above process, but it is preferable to carry it out continuously.

  Next, the crimped yarn for aliphatic polyester carpet obtained by the above method is set in a tufting machine and tufted on a base fabric such as an aliphatic polyester nonwoven fabric, aromatic polyester nonwoven fabric, or polypropylene nonwoven fabric, and then nonwoven fabric or polypropylene. A carpet can be obtained by backing with a backing material such as.

  If necessary, processing steps such as a steaming step, a brushing step, a spraying step, a dyeing step, a shearing step, and a polisher step can be added along the way.

  The carpet obtained from the crimped yarn for aliphatic polyester carpet of the present invention may be used as it is, or may be used as a mat such as a car mat by sewing and shaping.

  Carpets and car mats obtained from the crimped yarns for aliphatic polyester carpets of the present invention can be recycled by using sewing threads and backing materials for sewing and base fabrics similar to the aliphatic polyester used in the present invention. It is easy and preferable to simplify the process at the disposal stage.

  Preferred embodiments of the present invention are shown below, but the present invention is not limited to these descriptions.

A. Weight average molecular weight and degree of dispersion 10 mg of a crimped yarn for aliphatic polyester carpet or aliphatic polyester polymer sample of the present invention is dissolved in 4 ml of chloroform (for high performance liquid chromatograph), and a membrane filter having an opening of 0.15 μm is used. The sample solution was filtered. Then, using a water permeation chromatography (GPC) “Waters2690” manufactured by Waters, measured at 25 ° C. with an injection sample volume of 200 μl at a chloroform (for high performance liquid chromatograph) flow rate of 1.0 ml / min. Using a polystyrene 6 sample as a standard substance, the weight average molecular weight was calculated in terms of the main dispersion peak.

B. Epoxy Index of Epoxy Compound The epoxy index was calculated by calculating the epoxy index EI (unit: equivalent / kg) according to JIS K7236 (2001) and multiplying it by 1,000 to obtain the epoxy index (equivalent / t).

C. A crimped yarn sample for aliphatic polyester carpet of the present invention precisely weighed to a COOH end group concentration of 0.5 g was dissolved in an o-cresol (5% water) adjusting solution, and an appropriate amount of dichloromethane was added to this solution. It was measured by titrating with a 02N KOH methanol solution. At this time, since the oligomer of the aliphatic polyester may be hydrolyzed to generate COOH end groups, the COOH end group concentration of the polymer, the COOH end group concentration derived from the monomer, and the COOH end concentration derived from the oligomer are all added. The end group concentration is determined.

D. Total Fineness and Single Yarn Fineness About the crimped yarn for aliphatic polyester carpet obtained in the examples of the present invention, 100 m of crushed yarn was obtained, its weight W was determined, and the total fineness was determined by the following formula (III). . Further, the single yarn fineness was determined from the number N of filaments by the following formula (IV).
Total fineness (dtex) = W × 100 (III)
Single yarn fineness (dtex / F) = W × 100 ÷ N (IV).

E. Fiber Strength A Tensilen UCT-100 manufactured by Orientec was used to draw a strong elongation curve at a sample length of 200 mm and a tensile speed of 200 mm / min, and the stress value at the maximum point was defined as the fiber strength.

F. Melting point and crystallization characteristics of aliphatic polyester Using DSC “2920 modulated DSC” manufactured by TA Instruments, a melting point peak was obtained at a heating rate of 16 ° C./min and a sample amount of 10 mg, and the peak top position was taken as the melting point.

G. Crimp elongation rate Crimped yarn for aliphatic polyester carpet that has been unwound from a package that has been allowed to stand for 20 hours or more in an atmosphere of room temperature (20 to 35 ° C.) and relative humidity of 50 to 75% boils for 30 minutes under no load. After being immersed in water, it is dried to an equilibrium moisture content, which is used as a crimped yarn sample after boiling water treatment. An initial load is applied to the sample yarn to give a tension of display dtex × 0.0176 mN (1.8 mg / dtex), and after 30 seconds, the sample length is marked to 50 cm (L1). Next, a constant load that gives a tension of display dtex × 0.882 mN (90 mg / dtex) is applied to the sample, and after 30 seconds, the extended sample length (L2) is measured. Subsequently, the crimp elongation (%) was calculated | required by following formula (V).
Crimp elongation (%) = [(L2-L1) / L1] × 100 (V).

  Note that the atmospheric condition when the yarn is left before the boiling water treatment is a crimped state when used in an actual carpet manufacturing process, that is, a state in which the crimping characteristics have reached an equilibrium state due to moisture absorption. It is used because it does not take too much time to reach an equilibrium state and no condensation occurs.

H. Crimp sag The crimp elongation rate C1 immediately after production of the crimped yarn for aliphatic polyester carpet obtained in the examples of the present invention and the wrinkle after wet heat aging treatment in an environment of 50 ° C. × 95% RH for 400 hours The contraction / expansion rate C2 is set to the G. The crimp retention was determined from the following formula (VI). Those with a crimp retention of 80% or more were evaluated as ◎, those with 60% or more as ◯, those with less than 60% as ×, and those as ◯ or more as acceptable.
Crimp retention (%) = C2 ÷ C1 × 100 (VI).

I. Humid heat aging characteristics The crimped yarn for aliphatic polyester carpet of the present invention is removed, A wet heat aging treatment was performed under the same conditions as above, and the strength retention was determined from the following formula (VII) from the strength (T1) before the treatment and the strength (T2) after the treatment. Those with a strength retention of 70% or more were evaluated as ◎, those with 50% or more as ◯, those with less than 50% as x, and ◯ or more as acceptable.
Strength retention (%) = T2 ÷ T1 × 100 (VII).

[Example 1]
Nitrogen atmosphere in the presence of 99.8% pure L-lactic acid (D-lactic acid content 0.2%) as a starting material and bis (2-ethylhexanoate) tin catalyst (lactide to catalyst molar ratio = 10000: 1) Polymerization was carried out at 180 ° C. for 160 minutes. Thereafter, the mixture was cut in a cooling solvent to obtain polylactic acid pellets P1 having a weight average molecular weight of 160,000, a dispersity of 1.7, a particle size of 35 mg / piece, and a COOH end group concentration of 25.2 equivalent / t. Further, the amount of lactide was measured and found to be 0.11% by weight.

  The obtained polylactic acid pellets P1 were dried at a resin temperature of 80 ° C. under vacuum for 4 hours to obtain an absolutely dry state. TEPIC-S (substance name triglycidyl isocyanurate, epoxy index 10101 equivalent / t) 1.0% by weight manufactured by Nissan Chemical Co., Ltd. as a bifunctional or higher functional epoxy compound with respect to the polylactic acid pellets P1 After extruding at a kneading temperature of 200 ° C. with a machine (KZW-15TWIN), cooling and pelletizing were performed to obtain a polylactic acid resin composition P2.

  Thereafter, the polylactic acid resin composition P2 was dried at 100 ° C. under vacuum for 4 hours to obtain an absolutely dry state. Thereafter, the polylactic acid resin composition P2 is introduced into the storage hopper, and is spun at a discharge rate of 304.5 g / min from a spinneret having a round hole of 54 holes at a spinning temperature of 220 ° C. and a residence time of 8 minutes in the spinning machine. Stretching between rollers at a speed of 700 m / min, a preheating temperature of 70 ° C., and a draw ratio of 3.0 times, followed by crimping with heated air at a crimping preheating roll temperature of 130 ° C. and 200 ° C. After cooling the yarn, a polylactic acid crimped yarn of 1450 dtex-54F (single yarn fineness 26.9 dtex / F) was obtained at a winding tension of 0.08 cN / dtex. The results of physical property evaluation of the obtained polylactic acid crimped yarn are shown in Table 1. As a result, the settling of the crimp was highly suppressed, and an excellent quality was obtained.

[Example 2]
An aliphatic polyester crimped yarn was obtained in the same manner as in Example 1 except that the amount of the bifunctional or higher epoxy compound added was 0.5% by weight. The physical property values of the obtained sample are shown in Table 1, and the settling of crimp was sufficiently suppressed, and an excellent quality was obtained.

[Example 3]
An aliphatic polyester crimped yarn was obtained in the same manner as in Example 1 except that the amount of the bifunctional or higher epoxy compound added was 1.5% by weight. The physical property values of the obtained sample are shown in Table 1, and the settling of crimp was highly suppressed, and a product with excellent quality was obtained.

[Comparative Example 1]
A crimped yarn for an aliphatic polyester carpet was obtained in the same manner as in Example 1 without adding a bifunctional or higher epoxy compound. The physical property values of the obtained sample are shown in Table 1. Although the quality was excellent, the settling of the crimp was remarkable.

[Example 4]
A crimped yarn for an aliphatic polyester carpet was obtained in the same manner as in Example 1 except that the discharge hole shape of the spinneret was changed to the Y cross section (slit width 0.12 mm, slit length 2 mm). The physical property values of the obtained sample are shown in Table 2, and the settling of crimp was highly suppressed, and an excellent quality product was obtained.

[Example 5]
A crimped yarn for an aliphatic polyester carpet was obtained in the same manner as in Example 1 except that the discharge hole shape of the spinneret was a hollow section (3-slit type, slit width 0.1 mm, slit PCD 3.0 mm). The physical property values of the obtained sample are shown in Table 2, and the settling of crimp was highly suppressed, and an excellent quality product was obtained.

[Example 6]
A crimped yarn for an aliphatic polyester carpet was prepared in the same manner as in Example 1 except that the discharge hole shape of the spinneret was a slit-type cross section (slit ratio 1: 4, slit width 0.35 mm, slit length 1.4 mm). Obtained. The physical property values of the obtained sample are shown in Table 2, and the settling of crimp was highly suppressed, and an excellent quality product was obtained.

[Example 7]
In the same manner as in Example 1 except that ARUFON UG-4030 (epoxy index 1800 equivalent / t, acrylic-styrene copolymer resin, weight average molecular weight 11,000) manufactured by Toagosei was used as the bifunctional or higher functional epoxy compound. Aliphatic polyester crimped yarn was obtained. The physical properties of the obtained sample are shown in Table 3, and the settling of crimp was highly suppressed, and an excellent quality product was obtained.

[Example 8]
In the same manner as in Example 1, except that ARUFON UG-4100 (epoxy index 1100 equivalent / t, acrylic-styrene copolymer resin, weight average molecular weight 9,200) manufactured by Toagosei was used as the bifunctional or higher functional epoxy compound. Aliphatic polyester crimped yarn was obtained. The physical properties of the obtained sample are shown in Table 3, and the settling of crimp was highly suppressed, and an excellent quality product was obtained.

[Example 9]
Aliphatic polyester fiber in the same manner as in Example 1 except that Nippon Oil & Fats Modiper A4200 (epoxy index 725 equivalent / t, ethylene-glycidyl acrylate-polymethyl methacrylate copolymer resin) was used as the bifunctional or higher functional epoxy compound. A crimped yarn was obtained. The physical properties of the obtained sample are shown in Table 3, and the settling of crimp was highly suppressed, and an excellent quality product was obtained.

[Example 10]
An aliphatic polyester crimped yarn was obtained in the same manner as in Example 1 except that MA-DGIC (monoallyl diglycidyl isocyanurate, epoxy index 8368 equivalent / t) manufactured by Shikoku Kasei Kogyo was used as the bifunctional or higher functional epoxy compound. It was. The physical properties of the obtained sample are shown in Table 3, and the settling of crimp was highly suppressed, and an excellent quality product was obtained.

[Example 11]
Aliphatic polyester crimped yarn was obtained in the same manner as in Example 1 except that Nagase ChemteX Denacol EX-920 (polypropylene glycol diglycidyl ether, epoxy index 5450 equivalent / t) was used as the bifunctional or higher functional epoxy compound. It was. The physical properties of the obtained sample are shown in Table 3, and the settling of crimps was sufficiently suppressed, and an excellent quality was obtained.

[Comparative Example 2]
An aliphatic polyester crimped yarn was produced in the same manner as in Example 1 except that Denacol EX-731 (N-glycidylphthalimide, epoxy index 4650 equivalent / t) manufactured by Nagase ChemteX was used instead of the bifunctional or higher functional epoxy compound. Obtained. The physical properties of the obtained sample are shown in Table 4. Although the quality was excellent, the settling of crimps could not be suppressed.

[Comparative Example 3]
Aliphatic polyester fiber in the same manner as in Example 1 except that Denacol EX-146 (n-tertbutylphenylglycidyl ether, epoxy index 4430 equivalent / t) manufactured by Nagase ChemteX was used in place of the bifunctional or higher functional epoxy compound. A crimped yarn was obtained. The physical properties of the obtained sample are shown in Table 4. Although the quality was excellent, the settling of crimps could not be suppressed.

[Example 12]
An aliphatic polyester crimped yarn was obtained in the same manner as in Example 1 except that the number of holes in the die was changed to 96. The physical property values of the obtained sample are shown in Table 5. The settling of crimp was sufficiently suppressed, and an excellent quality product was obtained.

[Example 13]
An aliphatic polyester crimped yarn was obtained in the same manner as in Example 1 except that the discharge rate was changed to 420 g / min. The physical property values of the obtained sample are shown in Table 5. The settling of crimp was sufficiently suppressed, and a product with good quality was obtained.

[Example 14]
An aliphatic polyester crimped yarn was obtained in the same manner as in Example 13 except that the number of holes in the die was changed to 96. The physical property values of the obtained sample are shown in Table 5. The settling of crimp was sufficiently suppressed, and an excellent quality product was obtained.

[Example 15]
An aliphatic polyester crimped yarn was obtained in the same manner as in Example 1 except that the preheating temperature for drawing was changed from 70 ° C. to 100 ° C. and the draw ratio was changed to 3.3 times. The physical property values of the obtained sample are shown in Table 5. The settling of crimp was sufficiently suppressed, and an excellent quality product was obtained.

Claims (3)

  For an aliphatic polyester carpet, comprising an epoxy-type end-blocking agent having two or more functions and an aliphatic polyester, wherein the epoxy-type end-blocking agent is at least partially reacted with the COOH end group of the aliphatic polyester. Crimped yarn.   The crimped yarn for an aliphatic polyester carpet according to claim 1, wherein the bifunctional or higher functional epoxy compound has at least one glycidyloxycarbonyl group or N- (glycidyl) amide group in one molecule.   A bifunctional or higher functional epoxy compound is a polymer containing a glycidyl acrylate ester, a polymer containing a glycidyl methacrylate ester, a polymer containing glycidyl p-allylbenzoate, a glycidylated product of isocyanuric acid, a bifunctional or higher acid end. The crimped yarn for an aliphatic polyester carpet according to claim 2, wherein the yarn is selected from at least one selected from the group consisting of glycidyl esters of polyvalent carboxylic acids.