JP4296335B2 - Polyester fiber - Google Patents

Description

【００２６】
【発明の効果】
従来のポリエステルにない分子量、分子量分布、モルフォロジーがコントロールされ、分子鎖の絡み合いが少なく延び切り鎖構造を持つ高強度ポリエステル繊維が得られる。
【図面の簡単な説明】
【図１】本発明に係る重合体及び比較重合体のDSCパターン。
【図２】本発明に係る重合体及び比較重合体のGPCパターン。[0001]
BACKGROUND OF THE INVENTION
The present invention provides a high-strength polyester fiber with controlled molecular weight, molecular weight distribution, and morphology.
[0002]
[Prior art]
Polyesters represented by polyethylene terephthalate (PET) are excellent in mechanical properties and chemical properties. Depending on the properties of each polyester, for example, high-strength fibers, films, various moldings for clothing and industrial materials. It is used for goods.
In general, the mechanical properties and thermal properties of these molded products are not governed solely by the chemical structure of the polyester, but are known to vary depending on the molecular weight, molecular weight distribution, and morphology of the polymer chain. In particular, in the case of high-strength fibers, it is considered preferable to have a chain structure that extends as a morphology in order to improve strength and elastic modulus.
In the case of polyethylene terephthalate (PET), which is a typical polyester, bis (2-hydroxyethyl) terephthalate is produced by esterification or transesterification of terephthalic acid or dimethyl terephthalate and ethylene glycol, and this is heated at high temperature under vacuum. It is industrially produced by a melt polycondensation method in which polycondensation is performed using a catalyst.
In such a method, it takes a very long polymerization time to obtain a high molecular weight, and since the polymerization temperature is high, thermal degradation occurs in a long polymerization reaction, and the molecular weight distribution Mw / Mn always becomes 2 by transesterification. There are problems such as the fact that the molecular weight distribution is close and the molecular weight distribution cannot be controlled, the form of the molecular chain is also a so-called random coil, the polyester molecular chain is always entangled, and the amount of cyclic trimer to be generated is large.
A method using solid phase polymerization is also known as a method for obtaining a high molecular weight polyester.
This method is a method in which a polyester chip obtained by melt polymerization is heated under a reduced pressure or in an inert gas at a temperature lower than the melting point of the polyester.
In this method, the polymer can be polymerized to a relatively high degree of polymerization while suppressing the deterioration of the polymer, and the amount of cyclic trimer contained in the polymer can also be suppressed. It is a random coil and entanglement of polyester molecular chains cannot be removed. Further, the molecular weight distribution Mw / Mn is a value larger than 2, but the molecular weight distribution is complexly correlated with the chip shape, polymerization temperature, etc., and cannot be sufficiently controlled.
[0003]
Also, there is a method of polymerizing from a cyclic oligomer as disclosed in JP-A-1-197522. In this method, since the polymerization temperature is higher than the melting point of the polyester, the molecular weight distribution Mw of the obtained polymer is Mw. / Mn has a value close to 2, and there is a problem that the cyclic trimer content is comparable to that of the polyester polymer obtained by melt polymerization.
In addition, in the Journal of Polymer Science Part A: polymer Chemistry, Vol. 38, 3360-3368 (2000), polyester is polymerized from a cyclic dimer, but the polystyrene-equivalent weight average molecular weight measured by GPC is about 44500 at most. The molecular weight is not obtained.
The reason why the high molecular weight polyester does not reach a high molecular weight by the above method is unknown, but it is speculated that conditions such as polymerization temperature, polymerization time, polymerization catalyst, etc. have influenced individually or in combination, and a high degree of polymerization was not obtained. The
As described above, in the conventional polyester polymerization method, the polymerization time of a product having a high molecular weight is long, the molecular weight distribution and morphology cannot be controlled, and a large amount of cyclic trimer is contained.
[0004]
[Problems to be solved by the invention]
It is an object of the present invention to provide a polyester fiber having a chain structure in which molecular weight, molecular weight distribution, and morphology are controlled and molecular chains are less entangled.
[0005]
[Means for Solving the Problems]
That is, the present invention comprises a polyester having substantially no branched structure and having a number average molecular weight of 25000 or more in terms of polystyrene measured by gel permeation chromatography (GPC) using ethylene terephthalate as a main repeating unit. Polyester polymer, characterized by having a half-width of a crystal melting peak of 10 ° C. or less and a cyclic trimer content determined by GPC of 0.8% by weight or less. It is a fiber made of coalescence.
Specifically, the weight average molecular weight / number average molecular weight is 2 or more in terms of polystyrene-converted molecular weight measured by GPC and fibers comprising the polyester polymer as described above, wherein the melting point is 260 ° C. or higher. It is the fiber which consists of the said polyester polymer characterized by the above-mentioned.
[0006]
The present invention will be described in detail below.
What is polyester in the present invention? The polyester in the present invention has terephthalic acid as the main acid component, and at least one glycol, preferably at least one alkylene glycol selected from ethylene glycol, trimethylene glycol, and tetramethylene glycol as the main glycol component. The target is polyester. Further, a polyester in which a part of the terephthalic acid component is replaced with another bifunctional carboxylic acid component may be used, and / or a part of the glycol component is replaced with the above-described glycol or other diol component other than the main component. Polyester may be used. Examples of the bifunctional carboxylic acid other than terephthalic acid used here include isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, β-hydroxyethoxybenzoic acid, p-oxybenzoic acid, and adipic acid. And aromatic, aliphatic and alicyclic bifunctional carboxylic acids such as sebacic acid and 1,4-cyclohexanedicarboxylic acid. Examples of the diol component other than the glycol include aliphatic, alicyclic and aromatic diol compounds such as cyclohexane-1,4-dimethanol, neopentyl glycol bisphenol A and bisphenol S, and polyoxyalkylene glycol. be able to.
In the present invention, the polyester fiber composed of the dicarboxylic acid component and the diol component is particularly preferably 80 mol% or more of the repeating units are ethylene terephthalate units.
Further, the polyester contains a small amount of other optional polymers, antioxidants, antistatic agents, dyeing improvers, dyes, pigments, matting agents, fluorescent brighteners, inert fine particles and other additives. May be. In particular, when adding inert fine particles, either the external precipitation method or the internal precipitation method can be employed.
[0007]
As a method for obtaining such a polyester cyclic oligomer, a synthetic method as disclosed in H. Repin, E. Papanikolau: Journal of Polymer Science, A-1, 7, 3426 (1969), etc., or Journal of Polymer Science Part A: A method of purifying from a powder adhering to the vicinity of a polyester molding apparatus, such as polymer Chemistry, Vol. 38, 3360-3368 (2000).
[0008]
In the fiber made of the polyester polymer of the present invention, the molecular weight can be controlled by the addition amount of the polymerization catalyst. In the present invention, polyester proceeds not by polycondensation but by ring-opening addition polymerization. Therefore, the polymerization catalyst functions as a catalyst and functions as a polymerization initiator in the present invention. Therefore, it is possible to control the number average molecular weight by controlling the catalyst addition amount.
Furthermore, in the polyester ring-opening addition polymerization of the present invention, control of water and alcohol in the pre-polymerization stage is important. Water and alcohol can serve as a reaction initiator for the ring-opening addition polymerization. Accordingly, the presence of water or alcohol needs to be removed at the pre-polymerization stage in order to reduce the degree of polymerization of the polyester. On the contrary, the number average molecular weight of the polyester can be controlled by adding a trace amount of water or alcohol based on the molar ratio in the pre-polymerization stage.
[0009]
In addition, any catalyst can be used in the polyester ring-opening addition polymerization of the present invention. For example, antimony compounds include antimony trioxide, antimony pentoxide, antimony acetate, and antimony glycoloxide. Germanium compounds include germanium dioxide and germanium tetrachloride. Titanium compounds include tetra-n-propyl titanate and tetraisopropyl. Titanate, tetra-n-butyl titanate, tetraisobutyl titanate, tetra-tert-butyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, lithium oxalate titanate, potassium oxalate titanate, ammonium oxalate titanate, titanium oxide, Composite oxides of titanium and silicon, zirconium, alkali metals, alkaline earth metals, etc., titanium orthoesters or condensed orthoesters, titanium Reaction product consisting of orthoester or condensed orthoester and hydroxycarboxylic acid, reaction product consisting of orthoester or condensed orthoester, hydroxycarboxylic acid and phosphorus compound of titanium, orthoester or condensed orthoester of titanium and at least two hydroxyls A reaction product composed of a polyhydric alcohol having a group, 2-hydroxycarboxylic acid and a base, and as a tin compound, dibutyltin oxide, methylphenyltin oxide, tetraethyltin, hexaethylditin oxide, triethyltin hydro Oxide, monobutylhydroxytin oxide, triisobutyltin acetate, diphenyltin dilaurate, monobutyltin trichloride, dibutyltin sulfide, dibuty Hydroxy tin oxide, methyl Stan non acid, such as ethyl Stan non acid.
[0010]
The fiber made of the polyester polymer according to the present invention is substantially branched having a number average molecular weight of 25,000 or more in terms of polystyrene measured by gel permeation chromatography (GPC) using ethylene terephthalate as a main repeating unit. The first characteristic is that the fiber is made of a polyester polymer made of polyester that does not contain a structure. That is, if the number average molecular weight is less than 25,000, a problem such as a decrease in fiber strength occurs. Preferably it is 28000 or more, More preferably, it is 29000 or more.
In addition, if there is a branch, problems such as the disruption of the extended chain due to the branch, or a decrease in the strength of the fiber made of the polymer due to defects in the branch itself occur. Therefore, branching within a range where such a problem does not occur is not excluded from the present invention.
In the present invention, the molecular weight distribution of the polyester depends on the dispersion state of the polymerization catalyst in the polyester cyclic oligomer at the stage of polymerization preparation. If it is uniformly dispersed, the molecular weight distribution Mw / Mn becomes close to 1, and if it is not uniform, Mw / Mn becomes large and becomes a value larger than 2.
[0011]
The second feature of the fiber made of the polyester polymer of the present invention is that the half width of the crystal melting peak is 10 ° C. or less. The reason why the full width at half maximum of the melting point peak is so small is presumed to be that the molecular chain of the polyester polymer fiber has an extended chain structure or a structure close thereto. This extended chain structure appears because the molecular chain is fixed at the same time as the molecular chain is extended by ring-opening addition polymerization. Therefore, when the half width of the crystal melting peak exceeds 10 ° C., the molecular chain is stretched and does not have a chain structure, and it is difficult to achieve the object of the present invention. The half width of the crystal melting peak is preferably 8 ° C. or less, more preferably 5 to 6 ° C.
[0012]
Further, it is desirable that the fiber composed of the polyester polymer according to the present invention has a cyclic trimer content of 0.8% by weight or less as determined by GPC. This is because when it exceeds 0.8% by weight, it becomes an impurity particularly in bottle applications, or problems such as a decrease in strength of fibers made of a polymer occur. Preferably it is 0.7 weight% or less, More preferably, it is 0.5 to 0.6 weight%.
[0013]
Further, the fiber made of the polyester polymer according to the present invention preferably has a melting point of 260 ° C. or higher. This is because when the temperature is lower than 260 ° C., the melting point of the polyester is lower than the original melting point, so that the heat resistance of the fiber made of the polymer is lowered. Preferably it is 265 degreeC or more, More preferably, it is 268-290 degreeC.
[0014]
Moreover, it is preferable that the fiber which consists of a polyester polymer which concerns on this invention is 2 or more in a weight average molecular weight / number average molecular weight in the polystyrene conversion molecular weight measured by GPC. This is because if it is less than 2, there will be a problem in flow characteristics during fiber molding. Preferably it is 2.5 or more, More preferably, it is 3-7.
[0015]
Such various polyesters can be formed into fibers by any method. For example, a conventional melt spinning method, drawing, solid phase extrusion and the like can be mentioned. However, in any molding method, the molding processing temperature is low and the molding processing time is preferably short, and more preferably it is below the melting point of the polyester. Particularly preferred is a solid-phase extrusion method.
[0016]
The resulting fiber has a tensile strength of 20 cN / dtex or higher, preferably 23 cN / dtex or higher, which is an unprecedented extremely high strength polyester fiber.
[0017]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these. In addition, the evaluation method of various characteristics followed the following method.
[0018]
DSC: 10 mg of polyester was used as a sample. Using Perkin Elmer DSC-7, the temperature was raised to 300 ° C. at a rate of temperature rise of 20 ° C./min.
[0019]
Number average molecular weight, weight average molecular weight, weight average molecular weight / number average molecular weight, CT content: Dissolve 10 mg of sample in 0.1 mL of hexafluoroisopropanol (HFIP), dilute with 2.5 mL of chloroform, and then add SHODEX GPC SYSTEM 24H (chloroform Solvent, reference: polystyrene), two KF-606M and one KF-502.5 were used as columns, and the temperature was 40 ° C., the flow rate was 0.5 ml / min, and UV detection was performed. The weight average molecular weight / number average molecular weight (Mw / Mn) was determined from the obtained number average molecular weight (Mn) and weight average molecular weight (Mw). The CT content was calculated by the area ratio between the CT peak and the whole.
Tensile strength: According to the definition of JIS-L1017, after leaving in a room where temperature and humidity were controlled at 20 ° C. and 65% RH for 24 hours, breaking strength, breaking elongation and initial elastic modulus were obtained with a tensile tester.
[0020]
Example 1
Polyester cyclic dimer was synthesized by a known synthesis method, and 100 mg of cyclic dimer and tetra-n-butoxy titanate as a catalyst were sealed in an ampule and heated at 190 ° C. for 500 minutes. Table 1 shows the physical properties of the obtained polymer. The DSC pattern is as shown in FIG. 1, and the GPC pattern is as shown in FIG.
The obtained polymer was subjected to solid phase extrusion at 250 ° C. to produce a fiber. The obtained fiber had a strength of 25 cN / dtex and was excellent in elastic modulus and dimensional stability.
[0021]
(Example 2)
The same operation as in Example 1 was performed except that the polymerization temperature and the polymerization time were set to 230 ° C. and heated for 2 minutes. Table 1 shows the physical properties of the obtained polymer.
Further, the obtained polymer was subjected to solid phase extrusion at 250 ° C. for fiberization. The obtained fiber had a strength of 23 cN / dtex and was excellent in elastic modulus and dimensional stability.
[0022]
(Comparative Example 1)
Heat-circulation type 2 liter stainless steel autoclave with stirrer is charged with high-purity terephthalic acid and its 2-fold molar amount of ethylene glycol, and 0.3 mol% of triethylamine is added to the acid component. Then, the esterification reaction was carried out for 120 minutes while distilling water out of the system to obtain a mixture of bis (2-hydroxyethyl) terephthalate (BHET) and oligomer (hereinafter referred to as BHET mixture) having an esterification rate of 95%. To this BHET mixture, 2.5 g / l ethylene glycol solution of antimony trioxide was added to 0.05 mol% as antimony atoms with respect to the acid component in the polyester, and 245 ° C. at normal pressure in a nitrogen atmosphere. For 10 minutes. Next, the reaction system was gradually heated to 275 ° C. over a period of 50 minutes, and the pressure in the reaction system was gradually reduced to 0.1 Torr, followed by a polycondensation reaction at 275 ° C. and 0.1 Torr. It took 39 minutes for the IV of PET to reach 0.65. Further, polyethylene terephthalate having IV of 0.65 dlg ⁻¹ obtained by the above polycondensation was chipped according to a conventional method. Table 1 shows the physical properties of the obtained polymer.
After drying the obtained PET resin chip, it is supplied to a melt extruder and discharged at 310 ° C. from a spinneret having 190 orifices with a hole diameter of 0.5 mmΦ, cooled according to a conventional method, and taken out at 500 m / min after oiling. Without subsequent winding, it was stretched 5.7 times to obtain a stretched polyester yarn of 1100 dtex, 190 filaments, and a strength of 6 cN / dtex. The mechanical properties of the obtained yarn were inferior to those of the examples.
[0023]
(Comparative Example 2)
The chip of Comparative Example 1 was subjected to solid phase polymerization at 230 ° C. in a nitrogen atmosphere to obtain a polyester chip having an intrinsic viscosity of 0.74. The time for the intrinsic viscosity to rise to 0.74 was 120 minutes. Table 1 shows the physical properties of the obtained polymer. After drying the obtained PET resin chip, it is supplied to a melt extruder and discharged at 310 ° C. from a spinneret having 190 orifices with a hole diameter of 0.5 mmΦ, cooled according to a conventional method, and taken out at 500 m / min after oiling. Without subsequent winding, the polyester was drawn 5.7 times to obtain a drawn polyester yarn of 1100 dtex, 190 filaments, and a strength of 7 cN / dtex. The mechanical properties of the obtained yarn were inferior to those of the examples.
[0024]
(Comparative Example 3)
10 g of polyethylene terephthalate cyclic trimer obtained by a known method and tetrabutoxy titanate as a catalyst were sealed in an ampoule and heated at 320 ° C. for 5 minutes. Table 1 shows the physical properties of the obtained polymer.
The obtained PET is dried, then supplied to a melt extruder, discharged from a spinneret having 190 orifices having a hole diameter of 0.5 mmΦ at 310 ° C., cooled and oiled according to a conventional method, taken up at 500 m / min, and continuously wound. Without taking, it was drawn 5.7 times to obtain a drawn polyester yarn of 1100 dtex, 190 filaments, and strength 7 cN / dtex. The mechanical properties of the obtained yarn were inferior to those of the examples.
[0025]
[Table 1]

[0026]
【The invention's effect】
The molecular weight, molecular weight distribution, and morphology that are not found in conventional polyesters are controlled, and high-strength polyester fibers having a chain structure with little chain entanglement are obtained.
[Brief description of the drawings]
FIG. 1 is a DSC pattern of a polymer according to the present invention and a comparative polymer.
FIG. 2 is a GPC pattern of a polymer according to the present invention and a comparative polymer.

Claims (3)

A cyclic dimer is subjected to ring-opening addition polymerization at 190 to 230 ° C., and the number average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) using ethylene terephthalate as a main repeating unit is substantially 25,000 or more. A fiber formed by a solid phase extrusion method, which is made of a polyester polymer that does not contain a branched structure in which the half-value width of the crystal melting peak is 10 ° C. or less, and the cyclic trimer obtained by GPC A polyester fiber comprising a polymer having a content of 0.8% by weight or less and a tensile strength of 20 cN / dtex or more . The polyester fiber comprising the polyester polymer according to claim 1, having a melting point of 260 ° C or higher. The polyester fiber according to claim 1, wherein the weight average molecular weight / number average molecular weight is 2 or more in terms of polystyrene-converted molecular weight measured by GPC.

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