JP2003183482A - Aliphatic polyester resin composition, and molded item and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aliphatic polyester resin composition which has a melt viscosity lower than and mechanical properties superior to those of an ordinary aliphatic polyester. <P>SOLUTION: The aliphatic polyester resin composition contains a lactam and/or a lactam oligomer blended therein. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aliphatic polyester which has a lower melt viscosity than ordinary aliphatic polyesters and is excellent in mechanical properties.

[0002]

2. Description of the Related Art Recently, development of a polymer material that decomposes in a natural environment has been earnestly desired for environmental problems on a global scale. Research and development of various polymers such as aliphatic polyester and practical use Attempts to realize this are becoming more active. Attention has been focused on polymers that are decomposed by microorganisms, that is, biodegradable polymers.

On the other hand, most conventional polymers use petroleum resources as raw materials, but it is possible that petroleum resources will be depleted in the future, and due to the large consumption of petroleum resources, they will be stored underground in the geological era. It is feared that the carbon dioxide that had been released will be released into the atmosphere, and that global warming will become more serious. However, if polymers can be synthesized from plant resources that take in carbon dioxide from the atmosphere and grow and grow, not only can we expect that global warming can be suppressed by the carbon dioxide cycle, but there is also the possibility that the problem of resource depletion can be solved at the same time. . Therefore, attention has been focused on polymers made from plant resources, that is, polymers using biomass.

From the above two points, biodegradable polymers utilizing biomass have attracted great attention and are expected to replace conventional polymers derived from petroleum resources. However, biodegradable polymers using biomass generally have the problems of low mechanical properties and low heat resistance and high cost. As a biodegradable polymer using biomass that can solve these problems, polylactic acid is currently receiving the most attention. Polylactic acid is a polymer using lactic acid as a raw material, which is obtained by fermenting starch extracted from plants, and has the best balance among mechanical properties, heat resistance and cost among biodegradable polymers using biomass. The development of fibers and films using this is being carried out at a rapid pace.

However, since aliphatic polyesters generally have a small interaction between molecular chains, they are poor in stretchability, and in order to secure spinnability and film-forming property, the weight average molecular weight must be 100,000 or more. . Therefore, the melt viscosity is excessively high,
Molten polymer transfer process during melt spinning and film formation, filtration process,
The process pressure in the die discharge process tends to be abnormally higher than that of polyethylene terephthalate (PET), which is a general-purpose polymer. Incidentally, PET usually has a weight average molecular weight of 4.5.
The melt viscosity is low and there is no such problem. In this way, the melt molding (fiber, film, etc.) equipment of aliphatic polyester requires selection of materials that can withstand high process pressure and special design, and conventional PET equipment cannot be diverted, resulting in cost reduction in the melt molding process. There was a problem leading up. Therefore, while keeping the molecular weight high,
A low viscosity aliphatic polyester was desired.

By the way, an aliphatic polyester generally has a low melting point, and even polylactic acid belonging to a high melting point has a melting point of about 170.
The temperature is very low compared to general-purpose polymers such as PET and nylon 6. Therefore, in polylactic acid, the melting point is 220 ° C due to the stereocomplex that blends poly-L-lactic acid and poly-D-lactic acid to form crystals with a pair of molecular chains.
It has been reported that it can be improved to some extent. For this reason, the melt-forming temperature of the stereo complex had to be 260 ° C or higher, but the thermal decomposition temperature of polylactic acid was 250
Since the temperature was up to 260 ° C, there was a problem that smoke was generated during melt molding and that the molecular weight was significantly reduced. On the other hand, if the melt-forming temperature of the stereocomplex is set to around 240 ° C. in order to suppress the thermal decomposition, there is a problem that the melt viscosity becomes higher and the melt-forming becomes difficult. Therefore, in order to lower the melt molding temperature, a low-viscosity aliphatic polyester is desired while keeping the molecular weight high.

Further, as described above, even the most balanced polylactic acid among aliphatic polyesters does not have mechanical properties comparable to those of PET which is a conventional general-purpose polymer, and further improvement in mechanical properties is desired. It was

As described above, the aliphatic polyester has various problems, but if these problems can be solved at the same time, the performance of the aliphatic polyester can be greatly improved and the cost can be reduced, and the application can be greatly expanded. There was a possibility to be. For this reason, there has been a strong demand for a product having a low viscosity and high mechanical properties, which exceeds conventional aliphatic polyesters.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides an aliphatic polyester which has a lower melt viscosity than ordinary aliphatic polyesters and is excellent in mechanical properties.

[0010]

The above object is achieved by an aliphatic polyester resin composition characterized in that a lactam and / or a lactam oligomer is blended.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has found that lactams and / or lactam oligomers are excellent additives capable of solving the above problems with respect to aliphatic polyesters, and have much higher performance than conventional aliphatic polyesters. It is a design of the aliphatic polyester.

The term "aliphatic polyester" as used in the present invention means a polymer in which an aliphatic alkyl chain is linked by an ester bond, for example, polylactic acid, polyhydroxybutyrate, polybutylene succinate, polyglycolic acid, polycaprolactone. Etc. Of these, polylactic acid is most preferable as described above. Moreover, polylactic acid means a polymer of lactic acid, and it is preferable that the optical purity of the L-form or D-form is 90% or more because the melting point is high. Further, components other than lactic acid may be copolymerized, or polymers other than polylactic acid, particles, additives such as flame retardants, antistatic agents and the like may be contained, as long as the properties of polylactic acid are not impaired. However, from the viewpoint of biomass utilization and biodegradability, it is important that the content of the lactic acid monomer as a polymer is 50% by weight or more. Lactic acid monomer content is preferably 75 weight
% Or more, more preferably 96% by weight or more. In addition, the molecular weight of the polylactic acid polymer is preferably 100,000 to 500,000 in terms of weight average molecular weight because of good balance between mechanical properties and moldability.

The lactam in the present invention refers to a cyclic amide compound and its derivative, for example, β-butyrolactam, γ-butyrolactam, δ-valerolactam and ε.
-Caprolactam, 1,1-dimethyl-γ-butyrolactam and the like can be mentioned, but ε-caprolactam is most versatile and preferred. Also, not only one amide bond but two
One or more may be included in the molecule. The lactam oligomer means a ring-opening polymerized lactam, and in order to maintain good compatibility with the aliphatic polyester, the molecular weight is preferably 5000 or less. Further, it is preferable that the lactam has one amide bond, since there is no side reaction such as chain linkage. The lactam may be in the form of being bound to another molecule.
-Caprolactam-bound (lactam-blocked isocyanate) and the like can be mentioned. Since ε-caprolactam simple substance is deliquescent, a device for handling under dry or nitrogen atmosphere is required, but since this lactam-blocked isocyanate has almost no hygroscopic property, a drying process,
There is an advantage that a device under a nitrogen atmosphere is not required.

In the present invention, it is important that the lactam and / or the lactam oligomer is blended with the aliphatic polyester. Here, the blend means the following. That is, it is important that the blended lactam and / or lactam oligomer and the aliphatic polyester are compatible with each other, but little copolymerization is performed. When the lactam and / or the lactam oligomer is copolymerized with the aliphatic polyester, the melting point is lowered, so that the reaction should not be actively performed.
It is preferable to avoid copolymerization as much as possible. The melting point reduction is preferably within the range of 0 to -3 ° C from that of virgin aliphatic polyester.

The blending ratio of lactam and / or lactam oligomer is 0.01 to 5 wt% with respect to the total blended polymer in order to suppress bleeding in the melt molding process.
It is preferable that Especially when a lactam monomer is used, the blend ratio is preferably 0.01 to 1 wt%. The blend ratio is more preferably 0.1 to 0.5 wt%.

The aliphatic lactam and / or lactam oligomer blended aliphatic polyester of the present invention is compared to virgin aliphatic polyester unblended with lactam and / or lactam oligomer.
The effect of significantly reducing the viscosity is exhibited. In fact, it is possible to set the melt viscosity to 2/3 or less as compared with the virgin aliphatic polyester. The reason for the thinning effect of this lactam and / or lactam oligomer is not clear, but it is considered that the lactam and / or lactam oligomer penetrates between the aliphatic polyester molecular chains and acts like a roller.

Therefore, the aliphatic polyester of the present invention has the advantage that the process cost can be kept low because the conventional melt molding apparatus for PET can be used. Molded articles using this include fibers, films, sheets,
Examples include injection molded products, extrusion molded products, blow molded products and the like.

The fact that the melt viscosity can be lowered also has an advantage that the melt molding temperature can be lowered in the melt molding of the stereocomplex polylactic acid.

When it is applied to fibers and films, the effect that the molecular orientation in the spinning process and the stretching process can be further lowered as compared with virgin aliphatic polyester is exhibited. Therefore, for example, in the case of using undrawn yarn obtained at the same spinning speed in the fiber, in the present invention, the draw ratio can be set higher than that in the case of using the conventional virgin aliphatic polyester. That is, when compared with the same fineness, in the present invention, the discharge amount of the polymer per unit time during spinning can be increased, and the productivity per unit time can be greatly improved. For this reason,
For fibers, it is possible to reduce costs in the yarn making process.

An example of the method for producing fibers in the present invention is shown below. First, a step of melting an aliphatic polyester blended with a lactam and / or a lactam oligomer, a second step of transferring the molten polyester, a third step of filtering the molten polyester, and a fourth step of discharging the molten polyester from a die. The aliphatic polyester fiber can be obtained by the step, the fifth step of taking out the discharged yarn, and the sixth step of stretching the yarn. If necessary, the obtained aliphatic polyester may be subjected to thread processing such as crimp processing. In the step of blending the lactam / and / or lactam oligomer with the aliphatic polyester, it is possible to add the lactam and / or the lactam oligomer during the polymerization of the aliphatic polyester, but the polymerization was completed from the viewpoint of suppressing the copolymerization as much as possible. It is preferable to blend with an aliphatic polyester, that is, an aliphatic polyester once chipped. As a blending method,
After the lactam and / or lactam oligomer is solidly blended with the aliphatic polyester chips, they may be melt-blended with an extrusion kneader or a static kneader, or the aliphatic polyester and the lactam and / or lactam oligomer may be melted separately. After that, it may be melt-blended by an extrusion kneader or a static kneader. The temperature of the melt blending is preferably set to the melting point of the aliphatic polyester + 20 ° C. to the melting point + 80 ° C. in order to suppress thermal decomposition while obtaining sufficient fluidity.
Further, in the second to fourth steps as well, in order to obtain sufficient fluidity and suppress thermal decomposition, the step temperature is preferably set to the melting point of the aliphatic polyester + 20 ° C to the melting point + 80 ° C. In particular, in the fourth step, which is the spinning step, the spinning temperature is preferably set to the melting point of the aliphatic polyester + 20 ° C. or higher in order to suppress variations during spinning. From the viewpoint of suppressing thermal decomposition of the aliphatic polyester, the spinning temperature is preferably set to the melting point of the aliphatic polyester + 80 ° C or lower. The yarn take-up speed in the fifth step is 1000 to 1200 from the viewpoint of improving production efficiency while suppressing yarn breakage.
It is preferably 0 m / min.

The aliphatic polyester fiber obtained by the present invention preferably has a strength of 3.0 cN / dtex or more in order to keep the process passability in forming a fiber product and the mechanical strength of the product sufficiently high. It is more preferably 4.0 cN / dtex or more. Further, it is preferable that the elongation of the aliphatic polyester fiber is 15 to 70% because the process passability when the fiber is made into a fiber product is improved. The elongation is more preferably 25 to 50%.

Regarding the cross-sectional shape of the aliphatic polyester fiber, a multi-lobed cross section such as a round cross section, a hollow cross section, and a trilobal cross section,
It is possible to freely select other modified cross sections. The form of the fiber is not particularly limited such as long fiber and short fiber, and in the case of long fiber, it may be multifilament or monofilament.

The aliphatic polyester fiber obtained in the present invention can be in the form of various textile products such as woven fabric, knitted fabric, non-woven fabric, and heat compression molded products such as cups.

Further, the molded product using the aliphatic polyester blended with the lactam and / or the lactam oligomer of the present invention has an advantage that the mechanical properties are remarkably improved as compared with the molded product using the virgin aliphatic polyester. is doing. For example, when fibrous, compared to those using virgin aliphatic polyester, the strength is 15% or more,
It is also possible to improve the yield stress by 30% or more.

The aliphatic polyester resin composition of the present invention is used not only for clothing such as shirts, blouson and pants but also for clothing materials such as cups and pads, curtains, carpets, mats, furniture, etc. as fibers and products using the same. It can also be suitably used for industrial materials such as interiors, automobile interiors, belts, nets, ropes, heavy cloths, bags, sewing threads, felts, non-woven fabrics, filters and artificial grass.

Further, the aliphatic polyester resin composition of the present invention is used for a fiber as described above, a film,
It can also be suitably used for sheets, extrusion molded products, injection molded products, blow molded products and the like.

[0027]

EXAMPLES The present invention will be described in detail below with reference to examples. The following methods were used as the measuring methods in the examples.

A. THF was mixed with a chloroform solution of a weight average molecular weight sample to prepare a measurement solution. This was measured by GPC, and the weight average molecular weight was calculated in terms of polystyrene.

B. Intrinsic Viscosity of Nylon The intrinsic viscosity of Nylon 11 was measured at 20 ° C. by adjusting a 0.5 wt% meta-cresol solution.

C. Mechanical properties At room temperature (25 ℃), initial sample length = 200mm, pulling speed = 2
The load-elongation curve was determined under the conditions specified in JIS L1013 at 00 mm / min. Next, divide the load value at break by the initial fineness,
Using that as the strength, the elongation at break was divided by the initial sample length to determine the elongation, and the strength-elongation curve was obtained. And the yield stress was read as the yield stress.

D. Melting point of polymer Melting point was measured by 2nd run using DSC-7 manufactured by PERKIN ELMER. At this time, the sample weight was 10 mg and the temperature rising rate was 16 ° C./min.

E. Melt viscosity Using a Toyo Seiki Capillograph 1B, the melt viscosity was measured at 210 ° C and a shear rate of 1216 sec ^-1 .

F. Process pressure As the process pressure, the internal pressure of the pack during spinning was measured with a pressure gauge manufactured by Nagano Keiki.

Example 1 ε-caprolactam was blended with homopolylactic acid having a weight average molecular weight of 150,000 (optical purity 99% L lactic acid) at 220 ° C. using a biaxial extrusion kneader. At this time, ε-caprolactam was adjusted to be 1.0% by weight based on the whole blend polymer. The melting point of the blended polymer obtained here is 17
At 0 ° C, the melt viscosity was 1100 poise. The blended polymer chips were dried, melt spun at 220 ° C, and chimney 4
After the yarn was cooled and solidified with a cooling air of 25 ° C., the fiber oil agent was applied by the focusing oil supply guide 6, and the yarn was entangled by the entanglement guide 7 (FIG. 2). The process pressure at this time is 1
The process pressure could be suppressed as compared with the case where 2.6 MPa and virgin polylactic acid not blended with ε-caprolactam were used (Comparative Example 1). After that, it is collected by the unheated first take-up roller 8 at a peripheral speed of 1250 m / min, and then unheated by the second take-up roller 8.
The yarn was wound up via the take-up roller 9. This thread 11
The first roller 13 at a temperature of 90 ° C. and then stretched,
Roller 14 sets the heat at 130 ℃,
It was wound up via a roller 15 to obtain a drawn yarn 16 having 84 dtex, 24 filaments and a round cross section (FIG. 3). The draw ratio at this time was 4.1 times, and the draw ratio could be significantly increased as compared with the one using virgin polylactic acid without blending ε-caprolactam (Comparative Example 1). Physical properties of this are shown in Table 1.
In addition, although the strength / elongation curve is shown in FIG. 1, the mechanical properties were significantly improved as compared with the fiber using virgin polylactic acid not blended with ε-caprolactam (Comparative Example 1).

Example 2 Example 1 with the addition amount of ε-caprolactam being 0.5% by weight
Melt spinning and drawing were performed in the same manner as in. At this time, the draw ratio is
3.7 times. The physical properties of this are shown in Table 1, but the mechanical properties were significantly improved as compared with the fiber using virgin polylactic acid without blending ε-caprolactam (Comparative Example 1). Also, since the amount of ε-caprolactam added is small,
Compared to Example 1, the amount of smoke generated during spinning was small.

Example 3 Using homopolylactic acid having a weight average molecular weight of 200,000 (optical purity 99% L-lactic acid), the amount of ε-caprolactam added was 0.3% by weight, blending was carried out at 240 ° C., and the spinning temperature was 240 ° C. As in Example 1, melt spinning and drawing were performed. At this time,
The draw ratio was 3.3 times. The process pressure during spinning is 21.0 MPa
Compared with the one using virgin polylactic acid that did not blend with and ε-caprolactam (Comparative Example 2), the process pressure was significantly reduced. Further, since the amount of ε-caprolactam added was small, the amount of smoke generated during spinning was smaller than that in Example 1.

Example 4 1 mo of diphenylmethane diisocyanate melted at 120 ° C.
1 equivalent was added dropwise to a solution of ε-caprolactam (2.5 mol equivalent) in para-xylene with stirring. After completion of dropping, stirring was continued for 30 minutes, then cooled to room temperature, solids were separated by filtration and washed with water to obtain a lactam-blocked isocyanate. This is because two molecular equivalents of ε-caprolactam block two ends of diphenylmethane diisocyanate,
It has the property of reversibly dissociating / recombining ε-caprolactam (FIG. 4).

Then, 1% by weight of lactam-blocked isocyanate was added instead of ε-caprolactam (corresponding to 0.3% by weight of ε-caprolactam), and melt spinning and drawing were carried out in the same manner as in Example 3. At this time, the draw ratio was 2.8 times. The process pressure during spinning was 21.3 MPa and the process pressure was significantly lower than that in the case of using virgin polylactic acid in which ε-caprolactam was not blended (Comparative Example 2). Further, since the amount of ε-caprolactam added was small, the amount of smoke generated during spinning was smaller than that in Example 1.

Comparative Example 1 Virgin polylactic acid used in Example 1 (melt viscosity 1650 po
ise, melting point 170 ° C.) and then 220 as in Example 1.
Melt spinning at 80 ° C. and drawing were carried out to obtain drawn yarn with 84 dtex, 24 filaments, and round cross section. The process pressure during spinning was 19.2 MPa, and the draw ratio was 2.8.

Comparative Example 2 The virgin polylactic acid used in Example 3 was dried and then melt-spun at 240 ° C. in the same manner as in Example 3 to obtain a drawn yarn with 84 dtex, 24 filaments and a round cross section. Process pressure during spinning 3
It was as high as 4.2MPa and the base was deformed. The draw ratio was 2.5.

Comparative Example 3 The same procedure as in Example 1 was repeated except that oleic acid amide, which is an acyclic carboxylic acid amide, was used instead of ε-caprolactam.
Melt spinning at 80 ° C. and drawing were carried out to obtain drawn yarn with 84 dtex, 24 filaments, and round cross section. The process pressure during spinning was 19.0 MPa, and the draw ratio was 2.4, so the effect of reducing viscosity and the effect of improving draw ratio were not exhibited. Furthermore, since oleic acid amide has an aliphatic alkyl chain that is too long, it has poor compatibility with polylactic acid, and spinning becomes unstable, resulting in frequent yarn breakage. Also, the mechanical properties were not improved.

[0042]

[Table 1] Example 5 Melt spinning as in Example 1 with a spinning speed of 5000 m / min,
Stretching was performed to obtain a stretched yarn of 84 dtex and 144 filaments. The draw ratio at this time was 2.3 times. The strength of this drawn yarn was 4.0 cN / dtex and the elongation was 31%.

Comparative Example 4 Melt spinning was carried out in the same manner as in Comparative Example 1, except that the spinning speed was 5000 m / min.
Stretching was performed to obtain a stretched yarn of 84 dtex and 144 filaments. The draw ratio at this time was 1.4 times. The drawn yarn strength was 3.4 cN / dtex and the elongation was 30%.

Example 6 Melt spinning was carried out in the same manner as in Example 1 at a spinning speed of 10,000 m / min to obtain a wound yarn of 24 filaments of 56 dtex.
The strength of this winding yarn was 3.3 cN / dtex and the elongation was 25%.

Comparative Example 5 Melt spinning and drawing were carried out in the same manner as in Comparative Example 1 at a spinning speed of 10,000 m / min to obtain a 56 dtex, 24 filament drawn yarn. The process pressure during spinning was as high as 40.5 MPa, and the spinneret was deformed. The strength of this winding yarn was 1.0 cN / dtex and the elongation was 15%.

[0046]

[Table 2] Example 7 Melt spinning was performed in the same manner as in Example 5 to obtain an undrawn yarn. This was subjected to draw false twisting with a heater 18 temperature of 130 ° C. and a draw ratio of 2.2 times to obtain a false twisted yarn (FIG. 5). At this time, a triaxial twister made of urethane disk was used as the rotor 20. The stretching ratio could be increased as compared with the one using virgin polylactic acid to which ε-caprolactam was not added (Comparative Example 6).

Comparative Example 6 Melt spinning was carried out in the same manner as in Comparative Example 4 to obtain an undrawn yarn. This was drawn and false twisted in the same manner as in Example 7 to obtain a false twisted yarn. The draw ratio at this time was 1.3 times.

Example 8 Homopoly L lactic acid having a weight average molecular weight of 200,000 (optical purity 99% L
(Lactic acid) and homopoly D lactic acid having a weight average molecular weight of 100,000 (optical purity 99% D lactic acid) were mixed at 1: 1 and blended at 260 ° C. using a twin-screw extrusion kneader. The melting point of this L-form / D-form blend polylactic acid was 220 ° C., which was significantly higher than that of homo-L polylactic acid. The L-form / D-form blend polylactic acid chips obtained here were dried, and 0.5% by weight of ε-caprolactam was added thereto.
The solid blended product was melt-spun and stretched at 240 ° C. in the same manner as in Example 5 to obtain a stretched yarn having a stereocomplex of 60 dtex and 24 filaments. The temperature of the second roller 14 during stretching was 160 ° C. The obtained fiber had a strength of 3.2 cN / dtex and an elongation of 35%.

Example 9 Melt spinning was performed in the same manner as in Example 8 except that ε-caprolactam was added at the time of blending homopoly L lactic acid and homopoly D lactic acid.
Stretching was performed to obtain a stretched yarn in which a stereo complex of 60 dtex and 24 filaments was formed. The polymer blending was carried out at 240 ° C. with a twin-screw extruder. The obtained fiber had a strength of 3.8 cN / dtex and an elongation of 36%.

Comparative Example 7 An L-form / D-form blend polylactic acid chip was obtained in the same manner as in Example 8. Melt spinning and drawing were performed in the same manner as in Example 8 except that ε-caprolactam was not added, and the spinning temperature was 260 ° C. to obtain a drawn yarn having a stereocomplex of 60 dtex and 24 filaments. However, since the spinning temperature was too high, a lot of smoke was observed due to the thermal decomposition of polylactic acid.
For this reason, the molecular weight was significantly reduced during spinning, and the strength of the obtained fiber was 1.8 cN / dtex and the elongation was 35%, which was inferior in mechanical properties.

[0051]

[Table 3] Example 10 Nylon 11 having an intrinsic viscosity of 1.45 and homopolylactic acid used in Example 1 were mixed with ε-caprolactam and blended at 220 ° C. using a twin-screw extruder. At this time, nylon 11 was added to the blended polymer in an amount of 10% by weight, ε-
Caprolactam was adjusted to 1.0% by weight based on the total weight of the blend polymer. The blended polymer chips obtained here were dried, melt-spun and drawn in the same manner as in Example 1 to obtain a drawn yarn of 84 dtex and 72 filaments. The process pressure during spinning was 15.0 MPa, and the draw ratio during drawing was 3.3 times. The strength of the obtained fiber is 3.0 cN / dtex and the elongation is 42.
%, The yield stress was 1.7 cN / dtex.

Comparative Example 8 Example 10 except that no ε-caprolactam was added.
Melt spinning and drawing were carried out in the same manner as above to obtain a drawn yarn of 84 dtex and 72 filaments. The process pressure during spinning was 22.0 MPa, and the draw ratio during drawing was 3.2. The strength of the obtained fiber is
The yield stress was 2.9 cN / dtex, the elongation was 58%, and the yield stress was 0.8 cN / dtex.

[0053]

[Table 4] Example 11 Melt spinning and drawing were performed in the same manner as in Example 1 except that an oligomer having a weight average molecular weight of 1000 was used instead of ε-caprolactam, to obtain a drawn yarn of 84 dtex, 24 filaments, and a round cross section. The process pressure during spinning was 13.0 MPa, and the draw ratio during stretching was 3.8 times. In addition, smoke generation during spinning was less than in Example 1. The strength of the obtained fiber is 4.
The yield was 1 cN / dtex, the elongation was 48%, and the yield stress was 1.1 cN / dtex.

Comparative Example 9 Nylon 6 having a weight average molecular weight of 25,000 was used in place of ε-caprolactam to obtain a blended polymer chip in the same manner as in Example 1 at 240 ° C. However, since the molecular weight of nylon 6 was too high, the compatibility with polylactic acid was poor and the gut was cloudy. The chips were dried, melt-spun and stretched in the same manner as in Example 1 to obtain a stretched yarn with 84 dtex, 24 filaments and a round cross section. Process pressure during spinning is 21.0MP
a, the stretching ratio in stretching was 2.8 times. The strength of the obtained fiber is 3.0 cN / dtex, the elongation is 42%, the yield stress is 0.7 cN / dtex.
Met.

[0055]

[Table 5] Example 12 Using the yarn obtained in Example 1 as a warp yarn and a weft yarn, a plain weave (weight per unit area: 80 g / m ² ) was produced. The plain weave obtained was scoured at 60 ° C. according to a conventional method and then subjected to intermediate setting at 140 ° C. Further, it was dyed at 100 ° C. according to a conventional method. The dyeing conditions at this time are shown below.

Dyeing temperature, time 100 ° C. × 60 minutes Dyster Dianix Black BG-FS 8% owf Bath ratio 1:50 (pH = 4.5) Reduction washing NaOH 0.5 g / liter, hydrosulfite 0.2 g / The cloth obtained at 60 ° C. for 20 minutes with a liter aqueous solution has a squeaky feeling and a soft feeling, has an excellent texture for clothing, and also has excellent color development (L ^* =
13.3).

Comparative Example 10 Using the yarn obtained in Comparative Example 1, a fabric was prepared and dyed in the same manner as in Example 12. However, the color development was inferior to that of Example 12 (L ^* = 20.2).

Example 13 The ε-caprolactam blended polylactic acid obtained in Example 2 was dried and charged into a single-screw extruder equipped with a screw having a diameter of 150 mm and heated at 240 ° C. to carry out melt extrusion. After being filtered in a fiber-sintered stainless metal filter, it is discharged in a sheet form from a T-die, and the sheet is adhered and solidified at a draft ratio of 3 at a speed of 20 m / min onto a cooling drum having a surface temperature of 25 ° C. and rapidly cooled. A substantially unoriented unstretched film was obtained.

Subsequently, the unstretched film was stretched 5.0 times in the machine direction of the film at a temperature of 85 ° C. by using a longitudinal stretching machine composed of a plurality of heated roll groups and utilizing the peripheral speed difference of the rolls. It was stretched at a ratio. After that, both ends of this film were held by clips, introduced into a tenter, and stretched in the width direction of the film at a stretching temperature of 85 ° C. and a stretching ratio of 4.5 times. Then 1
After heat treatment at a temperature of 40 ℃, after cooling to room temperature,
The film edge was removed to obtain a biaxially oriented film having a thickness of 20 μm.

Its longitudinal strength is 135 MPa and its lateral strength is
180MPa, longitudinal heat shrinkage was 1.5%, transverse heat shrinkage was 1.5%, and both strength and shrinkage were sufficient. The heat shrinkage was determined from the dimensional change when left in an atmosphere of dry heat of 120 ° C for 30 minutes under no load.

Comparative Example 11 Example 1 was repeated except that the polylactic acid used in Comparative Example 1 was used.
Film formation was carried out in the same manner as in 3 to obtain a biaxially oriented film having a thickness of 20 μm. The stretching ratio at this time was 3.5 times in the longitudinal direction and 3.0 times in the lateral direction, which were smaller than those in Example 13.

Its longitudinal strength is 110 MPa and its lateral strength is
The heat shrinkage in the longitudinal direction was 150 MPa, the heat shrinkage in the longitudinal direction was 2.5%, and the heat shrinkage in the lateral direction was 2.5%.

[0063]

[Table 6] Example 14 Polybutylene succinate (Showa High Polymer “Bionore”, melting point 118 ° C.) was used as an aliphatic polyester, 0.5% by weight of ε-caprolactam was added thereto, and biaxial extrusion kneading was carried out at 220 ° C. as in Example 1. Blended in the machine. The obtained chips were dried and melt-spun and stretched in the same manner as in Example 1 to obtain a stretched yarn of 84 dtex, 36 filaments, and a round cross section. The process pressure at this time was 15.0 MPa, and the draw ratio was
3.2 times, the stretching temperature was 75 ° C, and the heat setting temperature was 85 ° C. The obtained fiber had a strength of 3.4 cN / dtex and an elongation of 38%.

Comparative Example 12 The polybutylene succinate used in Example 14 had ε-
As in Comparative Example 1 without the addition of caprolactam 22
Melt spinning and drawing were performed at 0 ° C. to obtain a drawn yarn with 84 dtex, 36 filaments and a round cross section. The process pressure at this time is 25.0MP
a, the draw ratio was 2.2 times. The strength of the obtained fiber is 2.
The elongation was 7 cN / dtex and 39%.

[0065]

[Table 7]

[0066]

EFFECT OF THE INVENTION Since the aliphatic polyester of the present invention has a lower melt viscosity than ordinary aliphatic polyester, it has improved moldability and can reduce the process pressure. Further, the mechanical properties can be greatly improved, which can greatly contribute to cost reduction and expansion of applications of the aliphatic polyester molded product.

[Brief description of drawings]

FIG. 1 is a diagram showing the strength-elongation curves of the present invention and virgin polylactic acid fiber.

FIG. 2 is a view showing a spinning device.

FIG. 3 is a diagram showing a stretching device.

FIG. 4 is a diagram showing an example of a lactam-blocked isocyanate.

FIG. 5 is a diagram showing a drawing false twisting device.

[Explanation of symbols]

1: Spin block 2: Spin pack 3: Base 4: Chimney 5: Thread 6: Focused refueling guide 7: Confounding guide 8: First take-up roller 9: Second take-up roller 10: Winding thread 11: Undrawn yarn 12: Feed roller 13: First roller 14: Second roller 15: Third roller 16: drawn yarn 17: Feed roller 18: Heater 19: Cooling plate 20: Rotor 21: Delivery roller 22: False twisted yarn

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F071 AA43 AA54 AH19 BB06                 4J002 CF18W CL01X GK01                 4L035 BB31 BB33 BB34 BB91 EE20                       JJ18

Claims (6)

[Claims] 1. An aliphatic polyester resin composition comprising a lactam and / or a lactam oligomer blended therein. 2. An aliphatic polyester resin composition characterized in that the aliphatic polyester is polylactic acid. 3. A molded article comprising at least a part of an aliphatic polyester blended with a lactam and / or a lactam oligomer. 4. The molded product according to claim 3, wherein the molded product is a fiber. 5. An aliphatic polyester resin composition blended with a lactam and / or a lactam oligomer is melt-spun at a temperature not lower than the melting point of the aliphatic polyester + 20 ° C. and taken at a spinning speed of 1000 to 12000 m / min. A method for producing an aliphatic polyester fiber, comprising: 6. The method for producing an aliphatic polyester fiber according to claim 5, wherein the lactam and / or the lactam oligomer is blended with the aliphatic polyester between after the completion of the aliphatic polyester polymerization and immediately before the melt spinning. .