JP3893995B2 - Resin composition and molded body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high performance resin composition in which polyamide is uniformly blended with aliphatic polyester.
[0002]
[Prior art]
Recently, there has been a strong demand for the development of polymer materials that can be decomposed in the natural environment in response to environmental problems on a global scale, and research and development of various polymers such as aliphatic polyesters and attempts to put them into practical use are active. It has become. Attention has been focused on polymers that are degraded by microorganisms, that is, biodegradable polymers.
[0003]
On the other hand, most of the conventional polymers are made from petroleum resources, but they have been stored in the ground since the geological era due to the fact that the petroleum resources will be depleted in the future and that they are consumed in large quantities. There is concern that carbon dioxide will be released into the atmosphere and global warming will become more serious. However, if a polymer can be synthesized using plant resources that grow by taking in carbon dioxide from the atmosphere, it is possible not only to suppress global warming by carbon dioxide circulation, but also to solve the problem of resource depletion at the same time. . For this reason, attention has been focused on polymers using plant resources as raw materials, that is, polymers using biomass.
[0004]
From the above two points, biodegradable polymers using biomass attract great attention and are expected to replace conventional polymers made from petroleum resources. However, biodegradable polymers using biomass generally have problems such as low mechanical properties and heat resistance and high cost. As a biodegradable polymer utilizing biomass that can solve these problems, polylactic acid, which is a kind of aliphatic polyester, is currently attracting the most attention. Polylactic acid is a polymer made from lactic acid obtained by fermenting starch extracted from plants. Among biodegradable polymers using biomass, it has the best balance of mechanical properties, heat resistance, and cost. Development of resin products, fibers, films, sheets, and the like using this has been performed at a rapid pitch.
[0005]
However, even the most promising polylactic acid has several drawbacks compared to conventional petroleum-based polymers such as nylon. Among these, the large ones include low mechanical properties, heat resistance, and wear resistance. For this reason, it is conceivable to blend, for example, nylon 6 with polylactic acid to compensate for the above-mentioned drawbacks. However, nylon 6 usually has a problem that it is not compatible with polylactic acid and cannot be uniformly blended. Nylon 6 has a melting point of about 225 ° C., which is significantly higher than that of polylactic acid of about 170 ° C., and the process temperature of the polymer blend needs to be 250 ° C. or higher, which is the thermal decomposition temperature of polylactic acid. Thus, it has been difficult to uniformly blend polylactic acid with nylon.
[0006]
JP-A-7-173282 discloses an example of block copolymerization of nylon 6 and polycaprolactone, which is a kind of aliphatic polyester, in combination with a large amount of a compatibilizer. To be sure, if a technique called block copolymerization with a large amount of compatibilizer is used, polycaprolactone blocks and nylon 6 blocks should be alternately present in one molecular chain, even if the polymer blending is usually difficult. Can be mixed uniformly. However, in the block copolymerization, the melting point is remarkably lowered, and the melting point = 201 to 214 ° C. (melting point drop = 11 to 24 ° C.) even in nylon 6, which is a high melting point component. For this reason, the excellent heat resistance of nylon could not be fully utilized. Further, since the nylon 6 block domain is too small, the excellent wear resistance which is the bulk characteristic of nylon 6 cannot be fully utilized. In addition, since the temperature of the block copolymerization process reaches a high temperature of 260 ° C., when this is applied to polylactic acid as it is, there is a problem that significant thermal decomposition of polylactic acid occurs. Furthermore, halogenated aromatic monohydroxy compounds such as p-chlorophenol used as a compatibilizer are not only harmful to the human body, but also have a problem of high environmental burden.
[0007]
[Problems to be solved by the invention]
  The present invention is mainly composed of an aliphatic polyester that has excellent mechanical properties, heat resistance, and wear resistance, and has never existed before.Textiles and textile productsIs to provide.
[0008]
[Means for Solving the Problems]
  The above purpose isPolylactic acidIt has a sea-island structure in which polyamide is blended, and the domain size of the island component is 0.0011It is characterized by being μmFiber and the fiberAt least part ofFiber productsIs achieved.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
  In the present inventionUpoLilactic acid refers to a product obtained by polymerizing lactic acid, and the optical purity of L-form or D-form is preferably 90% or more, since the melting point is high. Moreover, in the range which does not impair the property of polylactic acid, you may copolymerize components other than lactic acid, or may contain additives, such as a polymer other than polylactic acid, particle | grains, a flame retardant, and an antistatic agent. However, from the viewpoint of biomass utilization and biodegradability, it is important that the lactic acid monomer is 50% by weight or more as a polymer. The lactic acid monomer is preferably 75% by weight or more, more preferably 96% by weight or more. Further, the molecular weight of the polylactic acid polymer is preferably 50,000 to 500,000 in terms of weight average molecular weight, which is preferable because of a good balance between mechanical properties and moldability.
[0010]
The polyamide in the present invention refers to a polymer having an amide bond such as nylon, and examples thereof include nylon 6 and nylon 11. The polyamide may be a homopolymer or a copolymer, and may further contain additives such as particles, a flame retardant, and an antistatic agent.
[0011]
  Also,Polylactic acidSince the melting point of the polyamide is 170 ° C. or lower, the melting point of the polyamide is preferably 250 ° C. or lower, more preferably 210 ° C. or lower in consideration of lowering the blending temperature as much as possible. On the other hand, considering the heat resistance of the blend polymer, the melting point of the polyamide is preferably 150 ° C. or higher. Also,Polylactic acidIn order to improve the moldability of the blend polymer resin in which polyamide is blended with and the dimensional stability of the molded product, the blend polymer resin is preferably crystalline. For this reason, it is preferable that the polyamide to be blended is also crystalline. In addition, if a melting peak can be observed in the differential scanning calorimeter (DSC) measurement, it can be determined that the polymer is crystalline.
[0012]
  In consideration of the biodegradability of the blend polymer resin, the blend ratio of polyamide is preferably 40% by weight or less based on the entire blend polymer resin. on the other hand,Polylactic acidConsidering the point of improving the characteristics, the blend ratio of polyamide is preferably 5% by weight or more. The blend ratio of the polyamide is preferably 10 to 30% by weight.
[0013]
  In the present invention,Polylactic acidIt is important that the polyamide and the polyamide are uniformly blended. Here, the uniform blending means the following state. That is, the slice of the blend polymer molded body has a so-called sea-island structure by observation with a transmission electron microscope (TEM), and the size of the island domain is 0.001 in terms of diameter.1It means a state where it is reduced to μm. SpecialWith fiberIf you doDiameterSince it is often smaller than 20 μm, the size of the island domain is 0.001 in terms of diameter.1μm or lessThis is very important. In addition, it is preferable that the distribution of the island domain size is narrow, and it is preferable that 90% or more of the island component is distributed between 0.05 to 1 μm.
[0014]
  in this way,Polylactic acidIt is effective to increase the aliphaticity of the polyamide in order to increase the compatibility of the polyamide. For example, nylon 11 with a longer methylene chain length than nylon 6Polylactic acidExcellent compatibility with. Nylon 6 homopolymer is usuallyPolylactic acidIt is difficult to uniformly blend, but there are cases where uniform blending is possible by increasing the aliphaticity by copolymerization and lowering the melting point. Even if nylon 6 homopolymer is used, an appropriate compatibilizing agent is used, or nylon 6 is reduced in molecular weight orPolylactic acidUniform blending may be possible by increasing the molecular weight on the side.
[0015]
  In addition, since the present application is a polymer blend,Polylactic acidUnlike block copolymer where blocks and polyamide blocks exist alternately,Polylactic acidIt is important that the molecular chain and the polyamide molecular chain exist substantially independently. This difference in state can be estimated by the melting point drop of the polyamide in the homopolymer and the blend polymer. If the melting point drop of the polyamide is 3 ° C. or less,Polylactic acidAnd polyamide are hardly copolymerized (almost no ester-amide exchange)Polylactic acidIt can be seen that the molecular chain and the polyamide molecular chain are in the state of a polymer blend that exists independently. For this reason, in this application, the domain size of polyamide is large compared with the case of block copolymerization, and there exists a merit which can fully exhibit the bulk characteristic of polyamide. In other words, the wear resistance and high melting point of the spoiled polyamide can be fully utilized in block copolymerization. In this application, it is preferable that the melting point fall of the blended polyamide is 2 degrees C or less.
[0016]
  Since the resin composition of the present invention is excellent in moldability, it can be applied to higher melt molding such as fiber formation by spinning and film formation by film formation. Usually, glass fiber blends are used to improve the performance of resins. However, since the size of glass fibers is on the order of micron or more, when applied to fibers or films, the fiber diameter or film thickness is exceeded. Thus, it was practically impossible to produce yarn or film. However, in the blend polymer of the present invention, the island domain size is 1 μm or less.RutaTherefore, there is no such problem,Polylactic acidIt can greatly contribute to the enhancement of performance and the expansion of applications. In particular, fibers and fiber products are preferable because secondary processing using them is easy.
[0017]
In the fiber using the resin composition of the present invention, the strength at room temperature is preferably 1.0 cN / dtex or more in order to keep the process passability and the mechanical strength of the product sufficiently high. Moreover, when the elongation at room temperature of the fiber of the present invention is 15 to 70%, the process passability in making a fiber product is improved, which is preferable.
[0018]
In the fiber of the present invention, if the boiling yield is 0 to 20%, the dimensional stability of the fiber and the fiber product is good and preferable.
[0019]
Regarding the cross-sectional shape of the fiber of the present invention, a round cross-section, a hollow cross-section, a multi-leaf cross-section such as a trilobal cross-section, and other irregular cross-sections can be freely selected. The form of the fiber is not particularly limited, such as long fiber or short fiber. In the case of long fiber, it may be multifilament or monofilament.
[0020]
The fiber of this invention can take the form of various textile products, such as hot compression molded objects, such as a cup and a board, besides a textile fabric, a knitted fabric, and a nonwoven fabric.
[0021]
With the resin composition of the present invention, it is possible to overcome the disadvantages of conventional aliphatic polyesters and to improve the performance of aliphatic polyesters. For example, polylactic acid fibers have low yield stress and mechanically low dimensional stability, but the fibers of the present invention have improved yield stress and can improve mechanical dimensional stability. Thereby, even if a high-speed loom such as a water jet loom or an air jet loom is used, the weft defect does not stretch and the weaving defects can be greatly suppressed. In addition, polylactic acid fiber has a melting point of about 170 ° C, so when ironing it causes holes in the fabric due to the melting of the yarn, but this is greatly improved by blending polyamide with a higher melting point than polylactic acid. It can be done. Furthermore, since polylactic acid fibers have poor abrasion resistance, fibrillation is likely to occur due to slight rubbing, which tends to be a fabric defect, but this can be greatly improved by blending nylon with excellent abrasion resistance. . Thus, according to the present invention, the disadvantages of aliphatic polyester can be overcome and greatly contribute to the expansion of applications.
[0022]
Although the manufacturing method of the resin composition of this invention is not specifically limited, For example, the following methods are employable.
[0023]
That is, homopoly L lactic acid having a weight average molecular weight of 120,000 to 200,000 and nylon 11 (melting point 186 ° C.) are kneaded using a biaxial extrusion kneader at 210 to 240 ° C., and the nylon 11 is uniformly blended with polylactic acid. A resin composition can be obtained. And after melt-spinning this at 210-240 degreeC using a normal melt spinning apparatus, after taking up at a spinning speed 1000-7000 m / min and winding up once, extending | stretching temperature 80-150 degreeC, heat set temperature 80- By drawing at 160 ° C., the present fiber can be obtained. At this time, if the heat history is 245 ° C. or lower, the decomposition of the polylactic acid as the base polymer can be suppressed, which is preferable.
[0024]
The polyester resin composition of the present invention can be suitably used for cases, boards, life materials, vehicle materials, industrial materials, etc. in resin molding applications. Also, in textile applications, not only garments such as false twisting yarns, shirts, blousons, and pants, but also clothing materials such as cups and pads, interiors such as curtains, carpets, mats, and furniture, vehicle interiors, and belts. , Nets, ropes, heavy cloths, bags, sewing threads, felts, non-woven fabrics, filters, artificial turf, and other industrial materials. In addition, in film and sheet applications, it can be suitably used for packaging materials, labels, living materials such as wrap films, and industrial materials such as separators.
[0025]
【Example】
Hereinafter, the present invention will be described in detail with reference to examples. In addition, the measuring method in an Example used the following method.
[0026]
A. Weight average molecular weight of aliphatic polyester
Tetrahydrofuran was mixed with the chloroform solution of the sample to obtain a measurement solution. This was measured by gel permeation chromatography (GPC), and the weight average molecular weight was determined in terms of polystyrene.
[0027]
    B. Relative viscosity and intrinsic viscosity of nylon
  The relative viscosity of nylon 6 isDissolve nylon pellets in 98% sulfuric acid solution,0.01 g / mlTo concentrationAdjustAfter, Measured at 25 ° C.
[0028]
The intrinsic viscosity of nylon 11 was measured at 20 ° C. by adjusting a 0.5 wt% metacresol solution.
[0029]
C. Strength and elongation at room temperature
At room temperature (25 ° C.), an initial sample length = 200 mm, a pulling rate = 200 mm / min, and a load-elongation curve was obtained under the conditions shown in JIS L1013. Next, the load value at the time of breaking was divided by the initial fineness, which was taken as the strength, the elongation at break was divided by the initial sample length, and a strong elongation curve was obtained as the elongation.
[0030]
D. Boiling
Boiling yield (%) = [(L0−L1) / L0)] × 100 (%)
L0: Original length of the skein measured with an initial load of 0.09 cN / dtex after scraping the drawn yarn
L1: The skein measured at L0 was treated in boiling water for 15 minutes in a substantially load-free state, and after air drying, the skein length under an initial load of 0.09 cN / dtex
E. Melting point of polymer
The melting point was measured at 2nd run using DSC-7 manufactured by PERKIN ELMER. At this time, the sample weight was 10 mg, and the rate of temperature increase was 16 ° C./min.
[0031]
F. Observation of blend state of blend polymer
An ultrathin section was cut in the cross-sectional direction of the blended fiber, and the blended state of the polyamide was observed with a transmission electron microscope (TEM).
[0032]
TEM equipment: Hitachi H-7100FA type
Condition: Acceleration voltage 100kV
Here, as the size of the island domain, the domain was assumed to be a circle, and the size was calculated in terms of diameter from the area.
[0033]
G. Wear resistance test
Fibers were drawn and knitted so as to have a total fineness of 334 dtex to create a flat knitted fabric. Then, after setting the raw machine at 120 ° C., scouring at 98 ° C., and subsequently using the disperse dye Dianix Black BG-FS200, dyeing at 110 ° C. and finishing setting at 130 ° C. The density of the knitted fabric after the finishing set was set to all levels of wale 30 / inch × course 31 / inch. Then, a sample having a diameter of 120 mm is taken from the obtained flat knitted fabric, a hole having a diameter of 6 mm is made in the center, and attached to a Taber abrasion tester (Rotary Abraser) defined in ASTM D 1175, and CS # 10 wear is performed. The surface wear state of the fabric after 1000 rotation wear with a load of 500 gf (4.9 N) was observed with a ring. And it represented with the grade shown below and made the 3rd grade or more the pass.
[0034]
Grade 5: No change in state
Grade 4: Somewhat fuzzy
3rd grade: Slightly fuzzy
Second grade: A lot of fluff and thin yarn
First grade: those with thread breakage
H. Crimp characteristics of crimped yarn CR value
The crimped yarn was scraped off, treated in boiling water for 15 minutes in a load-free state, and air-dried for 24 hours. The sample was immersed in water under a load equivalent to 0.088 cN / dtex (0.1 gf / d), and the skein length L′ 0 after 2 minutes was measured. Next, the load corresponding to 0.088 cN / dtex was removed in water and replaced with a fine load equivalent to 0.0019 cN / dtex (2 mgf / d), and the skein length L′ 1 after 2 minutes was measured. And CR value was calculated by the following formula.
[0035]
CR (%) = [(L′ 0−L′1) / L′ 0] × 100 (%)
I. Number of crimps of crimped yarn
After the crimped yarn was freely shrunk in 100 ° C. hot water in a load-free state, the number of crimps was counted.
[0036]
Example 1
Nylon 11 having an intrinsic viscosity of 1.45 (melting point: 186 ° C.) is used as the polyamide, and this is mixed with homopoly L lactic acid (optical purity 99% L lactic acid, melting point 170 ° C.) having a weight average molecular weight of 150,000 at 220 ° C. in a biaxial kneader. Using the melt blend, a blend polymer was obtained. At this time, the blend ratio of nylon 11 was 10% by weight with respect to the blend polymer. When the melting point of this was measured, polylactic acid was observed at 170 ° C., and the melting point of nylon 11 was observed at 186 ° C. The blended polymer is dried, melt-spun at a spinning temperature of 220 ° C., and the spun yarn 5 is cooled and solidified by a chimney 4 with a cooling air of 25 ° C., and then a fiber oil agent is applied by a focused oiling guide 6. The yarn was entangled with the entanglement guide 7 (FIG. 2). There was no problem with the melt spinnability, and there was no yarn breakage after 100 kg winding. Thereafter, the film was taken up by the non-heated first take-up roller 8 at a peripheral speed of 1250 m / min, and then wound up through the non-heated second take-up roller 9. The yarn was preheated at a first roller 13 temperature of 90 ° C., stretched 3.2 times, heat-set at 130 ° C. with the second roller 14, wound through an unheated third roller 15, 84 dtex, A drawn filament 16 having 36 filaments and a round cross section was obtained (FIG. 3). There was no problem with the stretchability here, and there was no yarn breakage after winding 100 kg.
[0037]
When TEM observation of the cross section of the yarn of the obtained fiber was performed, the sea island structure was uniformly dispersed as shown in FIG. 1, and the domain size of the island component was 0.05 to 0.3 μm in terms of diameter. there were.
[0038]
Further, this fiber was knitted and ironed at 170 ° C., but there was no hole in the knitted fabric, and the heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.
[0039]
Example 2
A blend polymer was obtained in the same manner as in Example 1 except that the blend ratio of nylon 11 was 3% by weight. When the melting point of this was measured, polylactic acid was observed at 170 ° C., and the melting point of nylon 11 was observed at 186 ° C. Then, spinning and drawing were performed in the same manner as in Example 1 to obtain a drawn yarn having 84 dtex, 72 filaments, and a round cross section. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea island structure was taken, and the island domain size was 0.05 to 0.3 μm in terms of diameter.
[0040]
Furthermore, this fiber was knitted and ironed at 170 ° C. The heat resistance was improved compared to the conventional polylactic acid fiber (Comparative Example 1), but there were small holes in the knitted fabric. It was.
[0041]
Example 3
A blend polymer was obtained in the same manner as in Example 1 except that the blend ratio of nylon 11 was 20% by weight and the kneading temperature was 225 ° C. When the melting point of this was measured, the melting point of polylactic acid at 170 ° C. and the melting point of nylon 11 at 185 ° C. were observed. Moreover, when this TEM observation was performed, it had the uniform sea island structure, and the island domain size was 0.5-2.0 micrometers in conversion of the diameter. Then, in the same manner as in Example 1, spinning and stretching were performed at a spinning temperature of 225 ° C. to obtain a stretched yarn having 84 dtex, 72 filaments and a round cross section. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea-island structure was taken, and the island domain size was 0.05 to 0.4 μm in terms of diameter.
[0042]
Further, this fiber was knitted and ironed at 170 ° C., but there was no hole in the knitted fabric, and the heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.
[0043]
Example 4
A blend polymer was obtained in the same manner as in Example 1 except that the blend ratio of nylon 11 was 35% by weight and the kneading temperature was 230 ° C. When the melting point of this was measured, the melting point of polylactic acid was observed at 169 ° C. and nylon 11 was observed at 184 ° C. Then, in the same manner as in Example 1, spinning and drawing were performed at a spinning temperature of 230 ° C. to obtain a drawn yarn having 84 dtex, 24 filaments and a round cross section. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea island structure was taken, and the island domain size was 0.05 to 0.5 μm in terms of diameter.
[0044]
Further, this fiber was knitted and ironed at 170 ° C., but there was no hole in the knitted fabric, and the heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.
[0045]
Example 5
A blend polymer was obtained in the same manner as in Example 1 except that 0.5% by weight of ε-caprolactam was added as a thickener during melt blending. When the melting point of this was measured, polylactic acid was observed at 170 ° C., and the melting point of nylon 11 was observed at 186 ° C. Then, in the same manner as in Example 1, spinning and stretching (stretching ratio: 3.3 times) were performed to obtain a stretched yarn having 84 dtex, 144 filaments and a round cross section. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea-island structure was taken, and the island domain size was 0.05 to 0.9 μm in terms of diameter. This strong elongation curve is shown in FIG. 4, and the yield stress was significantly improved as compared with the conventional polylactic acid fiber (Comparative Example 1).
[0046]
Further, this fiber was knitted and ironed at 170 ° C., but there was no hole in the knitted fabric, and the heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.
[0047]
Example 6
A blend polymer was obtained in the same manner as in Example 1 except that the weight average molecular weight of homopoly L lactic acid was 200,000 (optical purity 99% L lactic acid, melting point 170 ° C.) and kneading temperature 235 ° C. When the melting point of this was measured, polylactic acid was observed at 170 ° C., and the melting point of nylon 11 was observed at 186 ° C. Then, spinning was carried out in the same manner as in Example 5 except that the spinning temperature was 240 ° C. and the peripheral speed of the first take-up roller 8 was 6000 m / min, and an 84 dtex, 36 filament yarn was obtained. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea-island structure was taken, and the island domain size was 0.05 to 0.9 μm in terms of diameter.
[0048]
Further, this fiber was knitted and ironed at 170 ° C., but there was no hole in the knitted fabric, and the heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.
[0049]
Example 7
Low molecular weight nylon 6 with a relative viscosity of 2.3 (melting point: 223 ° C.) is used as the polyamide, and this is mixed with homopoly-L lactic acid with a weight average molecular weight of 200,000 (optical purity 99% L lactic acid, melting point: 170 ° C.) at 245 ° C. The blended polymer was obtained by melt blending using a machine. When the melting point of this was measured, polylactic acid was observed at 170 ° C., and the melting point of nylon 6 was observed at 223 ° C. This blend polymer was dried, melt spun at a spinning temperature of 245 ° C., and melt spun and stretched in the same manner as in Example 1. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea-island structure was taken, and the island domain size was 0.05 to 0.9 μm in terms of diameter.
[0050]
Further, this fiber was knitted and ironed at 170 ° C., but there was no hole in the knitted fabric, and the heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.
[0051]
Comparative Example 1
The polylactic acid used in Example 1 was dried, melt-spun at 220 ° C., and the spun yarn 5 was cooled and solidified by a chimney 4 with a cooling air of 25 ° C., and then the fiber was fed by a focused oiling guide 6. The oil agent was applied and entangled with the entanglement guide 7 (FIG. 2). Thereafter, the yarn was taken up by the non-heated first take-up roller 8 at a peripheral speed of 1250 m / min, and then wound around the non-heated second take-up roller 9. This undrawn yarn 11 is preheated at a first roller 13 temperature of 90 ° C., then drawn 2.8 times, heat-set at 130 ° C. with a second roller 14, and wound through an unheated third roller 15. , 84 dtex, 24 filaments, a drawn yarn having a round cross section was obtained (FIG. 3). The strong elongation curve at 90 ° C. is shown in FIG. 4 and the physical properties are shown in Table 1. The yield stress was low. Further, this fiber was knitted in a tube and subjected to an ironing test at 170 ° C., but due to melting of the polylactic acid fiber, a large hole was formed in the knitted fabric, and the heat resistance was poor.
[0052]
    Comparative Example 2
PoA high molecular weight nylon 6 having a relative viscosity of 3.4 (melting point: 225 ° C.) was used as the lyamide, and the kneading temperature and the spinning temperature were 250 ° C., and nylon 6 was blended with polylactic acid in the same manner as in Example 7 and melt spinning was performed. The yarn became rainy in May and could not be wound. When the TEM observation of the cross section of this May rain thread was performed, the island domain size was large and was 20 μm or more in terms of diameter.
[0053]
[Table 1]
Example 8
The fibers obtained in Examples 1 to 7 were subjected to friction disk false twisting at a draw ratio of 1.35 times, a heater temperature of 130 ° C., and a processing speed of 400 m / min. There was no problem in processability, and thread breakage and fluff did not occur. Further, the CR value, which is an indicator of crimp characteristics, exceeded 20% and had sufficient crimp as a false twisted yarn. And when these abrasion resistance tests were performed, as shown in Table 2, the false twisted yarns using the fibers of Examples 1 to 7 as the raw yarn showed excellent abrasion resistance.
[0054]
[Table 2]
Comparative Example 3
The conventional polylactic acid fiber obtained in Comparative Example 1 was subjected to friction disk false twisting at a draw ratio of 1.35 times, a heater temperature of 130 ° C., and a processing speed of 400 m / min. Met. Next, when the hot plate temperature was lowered to 110 ° C. and processing was performed, there was still a problem with threading, but it was possible to wind the thread. The CR value, which is an index of crimp characteristics, was 21%, but the wear resistance was grade 2 and poor (Table 2).
[0055]
Example 9
In Example 8, the false twisted yarn obtained by using Example 5 as a processing raw yarn was used for warp and weft to produce a plain weave in a water jet loom. The obtained plain weave was scoured at 60 ° C. according to a conventional method, and then an intermediate set was applied at 140 ° C. This was excellent in quality without any weaving defects. Furthermore, it dye | stained at 110 degreeC according to the conventional method. The obtained fabric had a squeaky feeling and a soft feeling, and had an excellent texture for clothing. Moreover, there was no dyeing spot and it was excellent in quality.
[0056]
Comparative Example 4
A plain weave was produced in the same manner as in Example 9 using the false twisted yarn obtained in Comparative Example 3. However, the wefts were stretched by the tension at the time of driving the wefts, resulting in frequent weaving defects. When this was dyed in the same manner as in Example 9, stained spots were frequently generated and the quality was poor.
[0057]
Example 10
The blend polymer obtained in Example 1 was melt-spun, taken up at 1600 m / min as a tow, and stretched 4 times in a 90 ° C. water bath. And after passing through the crimper, it was cut and subjected to relaxation heat treatment at 90 ° C. to obtain a cut fiber having a single yarn fineness of 6 dtex and a fiber length of 60 mm. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea island structure was taken, and the island domain size was 0.05 to 0.3 μm in terms of diameter. This was hot compression molded at 220 ° C. to obtain a board having a thickness of 3 mm.
[0058]
In general, when the polymer is amorphous, it softens rapidly when the glass transition temperature is exceeded, but once the polymer crystallizes, the softening temperature can be made higher than the glass transition temperature, and in some cases, the polymer softens to near the melting point. In some cases, it can be suppressed. For this reason, the heat resistance of the board was evaluated as follows. That is, the obtained board was cut into a width of 2 cm, a fulcrum distance of 50 cm, a weight of 1 kg was placed in the center, and held at 80 ° C. for 20 minutes. After cooling, the weight was removed and the deformation of the board was observed. The board obtained here was different from that of poly L-lactic acid alone (Comparative Example 5), and no deformation was observed, confirming that the heat resistance was improved.
[0059]
Comparative Example 5
A board was obtained in the same manner as in Example 10 except that the polylactic acid used in Comparative Example 1 was used. However, this board was hardly crystallized, and when the heat resistance evaluation was performed by applying a load at 80 ° C. as in Example 10, deformation was observed and the heat resistance was poor.
[0060]
Example 11
The blend polymer obtained in Example 1 was dried and melt-spun at 230 ° C. At this time, the nozzle discharge hole was Y-shaped, and the nozzle discharge hole length was 0.5 mm. The spun yarn is taken up at 800 m / min, then subjected to two-stage drawing under the conditions of a first-stage draw ratio of 1.4 times and a total ratio of 4.0 times, and further crimped using a jet nozzle. Then, a bulky processed yarn for a carpet of 450 dtex, 90 filament was wound up. When the TEM observation of the cross section of the yarn of the obtained fiber was performed, a uniformly dispersed sea island structure was taken, and the island domain size was 0.05 to 0.3 μm in terms of diameter. The number of crimps was 15 / m, indicating good crimps.
[0061]
Comparative Example 6
A bulky processed yarn for carpet was obtained in the same manner as in Example 11 except that the polylactic acid used in Comparative Example 1 was used. The number of crimps was 6 / m, which was insufficient.
[0071]
【The invention's effect】
By using a resin composition characterized in that a polyamide is uniformly blended with the aliphatic polyester of the present invention, the mechanical properties, heat resistance and wear resistance, which were the disadvantages of the aliphatic polyester, are greatly improved. The application development of aliphatic polyester can be greatly expanded.
[Brief description of the drawings]
FIG. 1 is a TEM photograph showing a blended state of polyamide and aliphatic polyester in a blend polymer of the present invention.FIG. 1A is a copy of a TEM photograph, and FIG. 1B is a TEM photograph.
FIG. 2 is a view showing a spinning device.
FIG. 3 is a view showing a stretching apparatus.
FIG. 4 is a diagram showing a strong elongation curve of conventional polylactic acid fiber and nylon 11 blend fiber.
[Explanation of symbols]
      1: Spin block
      2: Spin pack
      3: Base
      4: Chimney
      5: Yarn
      6: Focused lubrication guide
      7: Confounding guide
      8: First take-up roller
      9: Second take-up roller
    10: Winding yarn
    11: Undrawn yarn
    12: Feed roller
    13: First roller
    14: Second roller
    15: Third roller
    16: drawn yarn

Claims (4)

A fiber having a sea-island structure in which polyamide is blended with polylactic acid , and the domain size of the island component is 0.001 to 1 μm. The fiber according to claim 1, wherein the polyamide is crystalline and has a melting point of 150 to 250 ° C. The fiber according to claim 1 or 2, wherein the blend ratio of the polyamide is 5 to 40% by weight based on the whole fiber . A fiber product comprising at least a part of the fiber according to any one of claims 1 to 3.