JP4487973B2 - Polyester resin composition - Google Patents

Description

  The present invention relates to a polyester resin composition excellent in high-temperature mechanical properties in which an aromatic polyester is blended with an aliphatic polyester.

  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.

  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.

  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.

  However, even the most promising polylactic acid has several drawbacks compared to conventional petroleum-based polymers. Among these, a large thing is that the high-temperature mechanical properties are poor. Here, the poor high-temperature mechanical properties indicate that when the glass transition temperature (Tg) of the polylactic acid polymer exceeds 60 ° C., it rapidly softens. For example, when a tensile test of polylactic acid fiber is performed at a different temperature, the shape softens rapidly from around 70 ° C., shows a shape close to flow at 90 ° C., and the dimensional stability is greatly reduced (FIG. 3). On the other hand, in nylon 6 which is a conventional polymer, such softening phenomenon is gradual and exhibits sufficient mechanical properties even at 90 ° C. (FIG. 3).

  Since polylactic acid has poor mechanical properties at high temperatures as described above, various problems have actually occurred. For example, a dashboard for automobiles made by injection molding of polylactic acid is softened at 60 to 70 ° C., so that there is a problem that it is easily deformed at a car interior temperature of 80 to 100 ° C. in summer.

In addition, the fiber has the following problems.
For example, when polylactic acid fiber is used for warp of a woven fabric, the yarn is glued for the purpose of improving the weaving property of the yarn and improving the weaving property, but when hot air drying is performed, the yarn is stretched by the tension applied to tension the warp. There was a problem of stretching. In addition, when false twist is applied to the polylactic acid fiber, the yarn softens rapidly on the hot plate, so the yarn does not twist and the crimp characteristics are inferior, and the yarn breaks on the hot plate, In some cases, false twisting itself becomes difficult. Furthermore, due to such troubles on the hot plate, the hot plate temperature can only be raised up to 110 ° C at the most, and not only the crimping property is low due to insufficient heat setting, but also the shrinkage rate of the yarn in boiling water It was also difficult to reduce the (boiling yield) to a practical level of 20% or less.

  Furthermore, aliphatic polyester generally has a low melting point, and even polylactic acid, which is a class having the highest melting point, is about 170 ° C. For example, when a fabric made of polylactic acid fiber is ironed, a hole is formed in the fabric due to melting of the polylactic acid fiber There was a problem.

Due to the above problems, aliphatic polyesters such as polylactic acid have a great limitation in application development. For this reason, aliphatic polyesters with improved mechanical properties and melting points at high temperatures have been desired.
JP-A-8-231838

  The present invention provides a polyester resin composition mainly composed of an aliphatic polyester, which has not been heretofore provided with excellent high-temperature mechanical properties and heat resistance.

The above object is achieved by the following means.
(1) a diol component are polymerized one or more long-chain dicarboxylic acid component 2～15Mol% co selected from adipic acid and sebacic acid to an aromatic polyester diol having 2 carbon atoms, a melting point of 170 to 250 ° C. A polyester resin composition , wherein the aromatic polyester is a blend of 5 to 40% by weight with an aliphatic polyester.
(2) aromatic polyester is characterized by crystalline der Rukoto (1) the polyester resin composition.
(3) The polyester resin composition according to (1) or (2), wherein the aliphatic polyester is polylactic acid.
(4) A molded product comprising at least part of the polyester resin composition according to any one of (1) to (3).
(5) The molded body according to (4), wherein the molded body is a fiber or a fiber product.
(6) The molded product according to (5), wherein the fiber is a crimped yarn.
(7) The molded body according to (4), wherein the molded body is a film or a sheet.
(8) The molded body according to (4), wherein the molded body is an injection molded body, an extrusion molded body, or a blow molded body.

  By using a polyester resin composition characterized in that a specific aromatic polyester is blended with the aliphatic polyester of the present invention, the high temperature mechanical properties and heat resistance, which were the disadvantages of the aliphatic polyester, are greatly improved. The application development of aliphatic polyester can be greatly expanded.

  The aliphatic polyester as used in the present invention refers to a polymer in which aliphatic alkyl chains are linked by an ester bond, and examples thereof include polylactic acid, polyhydroxybutyrate, polybutylene succinate, polyglycolic acid, and polycaprolactone. It is done. Of these, polylactic acid is most preferred as described above.

  Polylactic acid refers to a product obtained by polymerizing lactic acid, and the optical purity of L-form or D-form is preferably 90% or higher because of its high melting point. 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.

The aromatic polyester as used in the present invention refers to a polyester having an aromatic ring in the main chain or side chain, for example, polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT), polyhexamethylene. Examples include terephthalate (PHT). However, since homo-PET and homo-PBT generally have low compatibility with aliphatic polyesters, polymer blending with aliphatic polyesters has been virtually impossible. For this reason, in order to enhance the compatibility between the aromatic polyester and the aliphatic polyester, it is important to introduce aliphaticity into the main chain or side chain of the aromatic polyester. More specifically, it is important that the diol component of the aromatic polyester has 6 or more carbon atoms, or the aromatic polyester is copolymerized with a diol component having 6 or more carbon atoms and / or a dicarboxylic acid component. As the copolymer component, a long alkyl chain, a bisphenol A derivative, and the like are preferable. Examples of the long-chain alkyl chain include alkylene diols and long-chain dicarboxylic acids. Here, the alkylene diol includes, for example, alkylene oxide polymers and oligomers such as polyethylene glycol, and diols having a large number of carbon atoms such as neopentyl glycol and hexamethylene glycol. As the long-chain dicarboxylic acid is adipic acid and sebacic acid. The copolymerization ratio is 2 to 15 mol% with respect to the total amount of carboxylic acid in the case of diol and to the total amount of diol in the case of dicarboxylic acid. The aromatic polyester having 6 or more carbon atoms of the diol component or the aromatic polyester copolymerized with a diol component having 6 or more carbon atoms and / or a dicarboxylic acid, used in the present invention, is simply “specific” for convenience. Of aromatic polyester ”.

Furthermore, since the melting point of aliphatic polyester is generally 170 ° C. or lower, considering that the blending temperature should be lowered as much as possible, isophthalic acid or the like may be further copolymerized with a specific aromatic polyester to lower the melting point. preferable. The melting point of the particular aromatic polyester, 2 50 ° C. or less, good Mashiku is 230 ° C. or less. However, from the viewpoint of improving the heat resistance of the blend polyester resin obtained by blending a specific aromatic polyester in the aliphatic polyester and a molded article thereof, the melting point of the particular aromatic polyester 1 70 ° C. or more, good Mashiku is 200 ° C. or higher It is.

  Moreover, in order to improve the moldability and the dimensional stability of the molded polyester resin obtained by blending a specific aromatic polyester with an aliphatic polyester, the blended polyester resin is preferably crystalline. For this reason, it is preferable that the specific aromatic polyester to be blended is also crystalline. In addition, if a melting peak can be observed in a differential scanning calorimeter (DSC) measurement, it can be determined that the polymer is crystalline.

  In consideration of the biodegradability of the blended polyester resin, it is important that the blend ratio of the specific aromatic polyester is 40% by weight or less based on the whole blended polyester resin. On the other hand, considering the point of improving the high-temperature mechanical properties, it is important that the blend ratio of the specific aromatic polyester is 5% by weight or more. The blend ratio of the specific aromatic polyester is preferably 15 to 30% by weight.

  In the present invention, the reason why the high temperature mechanical properties are improved is considered as follows. That is, in general, aliphatic polyesters such as polylactic acid are considered to have low high-temperature mechanical properties because the interaction between the molecular chains is weak and the molecular chains are easy to slip through. Therefore, the high-temperature mechanical properties of the blended polyester resin are improved by supporting the aliphatic polyester molecular chain by strongly restraining the aliphatic polyester molecular chain by the strong interaction between the aromatic rings of a specific aromatic polyester. It is thought that.

  For this purpose, it is preferable to use crystallization of a specific aromatic polyester or high Tg. Moreover, in order to fully exhibit the effect of crystallization or high Tg, it is preferable that the specific aromatic polyester and the aliphatic polyester are appropriately compatible. Here, moderately compatible means that a specific aromatic polyester and an aliphatic polyester are phase-separated and adopt a so-called sea-island structure, but the aliphatic polyester penetrates to a certain extent in a specific aromatic polyester domain. It points to what you are doing. If such a unique blend state can be realized, the specific aromatic polyester can strongly restrain the aliphatic polyester. This state can be confirmed, for example, by observing a slice of the blended polyester molded body with a transmission electron microscope (TEM) and comparing the charged ratio of the aliphatic polyester and the specific aromatic polyester with the sea-island ratio obtained by TEM observation. Can do. Information can also be obtained from long period measurements by small angle X-ray scattering.

For example, in the blended fiber system of polylactic acid 80% by weight and copolymerized PET 20% by weight shown in Reference Example 1, the sea-island ratio obtained by TEM observation (FIG. 1) is 45 area%: 55 area%. As compared with the area ratio of 81% by sea area and 19% by area, the island ratio is significantly higher, suggesting that polylactic acid penetrates into the copolymerized PET domain. Moreover, the long period of the copolymerized PET is usually about 10 nm, but in Reference Example 1, it is about twice as large as 19 nm, and it can be interpreted that the copolymerized PET molecular chain partially sandwiches the polylactic acid molecular chain.

  On the other hand, if a specific aromatic polyester and aliphatic polyester are completely compatible with each other at the molecular level, the moldability is good, but the crystallization of each other is inhibited, or the Tg as a blended polyester due to the additivity of Tg. In some cases, the increase is small, the restraining effect of the specific aromatic polyester as described above is not exhibited, and the high-temperature mechanical properties cannot be improved.

  In addition, when a specific aromatic polyester and an aliphatic polyester are so-called incompatible, the aliphatic polyester cannot penetrate into a specific aromatic polyester domain, and the above-described effects are not exhibited, and high temperature mechanical properties Cannot be improved. Furthermore, in incompatible systems, the elastic behavior based on phase separation often develops strongly, and the moldability of the blended polyester is significantly impaired. Conventionally, homo-PET, homo-PBT and aliphatic polyester are incompatible with each other, and polymer blending has been substantially impossible.

Thus, in order to achieve both high-temperature mechanical properties and formability, the so-called blended state has a sea-island structure, and at least part of the island domain size is 0.001 to 10 μm in terms of diameter. It is preferable to have. In particular, in the case of a fiber or a film, it is preferable that at least a part of the island domain size is 0.001 to 1 μm in terms of diameter. Here, the island domain size can be measured by slicing the blended polyester resin or a molded product thereof and observing with a TEM. In addition, it is also preferable from the viewpoint of improving moldability that a part of the blended polyester adopts a structure in which sea islands are difficult to distinguish between the sea and islands of the sea island structure. For example, in Reference Example 1 described above, such a state can be observed in the fiber inner layer portion (FIG. 1).

  Since the polyester resin composition of the present invention is excellent in moldability, it is not only used for ordinary resin molding such as injection molding, extrusion molding, and blow molding, but more advanced melting such as fiberization by spinning and film formation by film formation. It can also be applied to molding. 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 blended polyester of the present invention, the specific aromatic polyester to be blended is sub-micron order or less, so that there is no such problem, and it can greatly contribute to the enhancement of the performance and the use of the aliphatic polyester. . In particular, fibers and fiber products are preferable because secondary processing using them is easy.

  In the fiber using the polyester 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. The strength at room temperature is preferably 2.0 cN / dtex or more. 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. The elongation at room temperature is more preferably 25 to 50%.

  As described above, the polylactic acid fiber, which is a typical example of aliphatic polyester, has a strong elongation curve shape close to flow at 90 ° C. (FIG. 3), and the strength is 0.5 cN / dtex or less. In the fiber of the present invention, the strength can be increased to 0.7 cN / dtex or more even at 90 ° C., and the creep characteristics can be greatly improved. As the creep characteristics, the elongation under 0.5 cN / dtex stress at 90 ° C. is used as an index. In the fiber of the present invention, this can be made 15% or less. Here, the elongation at 90 ° C. under 0.5 cN / dtex stress means that the fiber tensile test is performed at 90 ° C., and the elongation at a stress of 0.5 cN / dtex is read in the strong elongation curve diagram. Can be obtained (FIG. 2). The elongation under 0.5 cN / dtex stress at 90 ° C. is preferably 10% or less. Moreover, if the intensity | strength in 90 degreeC is 0.7 cN / dtex or more, the intensity | strength in the high temperature of the textiles which consist of a polylactic acid fiber can be improved, and it is preferable. The strength at 90 ° C. is more preferably 1.0 cN / dtex or more.

  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. The boiling yield is preferably 3 to 10%.

  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.

  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.

  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 clothing for false twisting, shirts, blousons, 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.

  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.

A. Weight average molecular weight of aliphatic polyester Tetrahydrofuran was mixed with the chloroform solution of the sample to prepare a measurement solution. This was measured by GPC, and the weight average molecular weight was determined in terms of polystyrene.

B. Intrinsic viscosity of aromatic polyester [η]
Measured in orthochlorophenol at 25 ° C.

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.

D. Elongation at 90 ° C. under 0.5 cN / dtex stress At a measurement temperature of 90 ° C., a strong elongation curve was obtained in the same manner as in C above, the elongation at 0.5 cN / dtex was read, and 0.5 cN / d at 90 ° C. It was set as the elongation under dtex stress.

E. Strength at 90 ° C. At a measurement temperature of 90 ° C., a strong elongation curve was obtained in the same manner as in D above, and the load value was divided by the initial fineness to obtain the strength at 90 ° C.

F. Boiling yield Boiling yield (%) = [(L0−L1) / L0)] × 100 (%)
L0: Original length of skein measured after squeezing the drawn yarn under an initial load of 0.09 cN / dtex L1: The skein measured for L0 was treated in boiling water for 15 minutes in a substantially load-free state and first after air drying Skein length under a load of 0.09 cN / dtex.

G. Tg and melting point of polymer Tg and melting point were 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.

H. Observation of Blend State of Blend Polyester Ultra-thin slices were cut in the cross-sectional direction of the blend fiber, and the blend state of the polyester was observed with a transmission electron microscope (TEM).
TEM equipment: H-7100FA type manufactured by Hitachi, Ltd. Conditions: acceleration voltage 100 kV
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. The sea-island ratio was calculated using image analysis software.

I. Wide-angle X-ray diffraction Using a 4036A2 type X-ray diffractometer manufactured by Rigaku Corporation, the diffraction intensity in the equator direction was measured under the following conditions.
X-ray source: Cu-Kα ray (Ni filter)
Output: 40kV x 20mA
Slit: 2 mmφ-1 ° -1 ° Detector: Scintillation counter counting recording device: RAD-C type step scan manufactured by Rigaku Corporation: 0.05 ° step integration time: 2 seconds.

J. et al. Small-angle X-ray scattering Small-angle X-ray scattering photographs were taken using a RU-200 type X-ray generator manufactured by Rigaku Corporation.
X-ray source: Cu-Kα ray (Ni filter)
Output: 50kV x 150mA
Slit: 0.5mmφ
Camera radius: 405mm
Exposure time: 300 minutes Film: Kodak DEF-5
Then, the long period was calculated from the distance r (mm) between the scattering points on the photograph using the Bragg equation.
J = λ / 2sin [{tan-1 (r / R)} / 2]
J: Long period (nm)
R: Camera radius (405 mm)
λ: X-ray wavelength (0.15418 nm).

K. Crimp characteristics and CR value of false twisted yarn The false twisted yarn was scraped and treated in boiling water for 15 minutes in a substantially 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, in water, the load corresponding to 0.0088 cN / dtex was removed and the load was changed to a fine load equivalent to 0.0018 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.
CR (%) = [(L′ 0−L′1) / L′ 0] × 100 (%).

L. The number of crimps of the crimped yarn The crimped yarn was shrunk freely in hot water at 100 ° C. in a substantially load-free state, and then the number of crimps was counted.

Reference example 1
As a specific aromatic polyester, copolymerized PET (melting point 220 ° C.) having an intrinsic viscosity of 0.65 obtained by copolymerizing 6 mol% of bisphenol A ethylene oxide adduct and 6 mol% of isophthalic acid was used, and this had a weight average molecular weight of 150,000. Homopoly L lactic acid (optical purity 99% L lactic acid) was melt blended at 235 ° C. using a biaxial kneader to obtain a blended polyester chip. At this time, the blend ratio of the copolymerized PET was 20% by weight with respect to the blended polyester. The Tg of this blended polyester chip was approximately equal to 61 ° C. and 60 ° C. of homopoly L lactic acid. This blended polyester chip is dried, melt-spun at a spinning temperature of 235 ° C., and the spun yarn 5 is cooled and solidified with a cooling air of 25 ° C. by the chimney 4, and then a fiber oil agent is applied by the converged oil supply guide 6. Then, the yarn was entangled by the entanglement guide 7 (FIG. 4). There was no problem with the melt spinnability, and there was no yarn breakage after 100 kg winding. Then, after taking up with the non-heated 1st take-up roller 8 of the peripheral speed of 1500 m / min, it wound up via the non-heated 2nd take-up roller 9. This yarn was preheated at a first roller 13 temperature of 90 ° C., then stretched 2.8 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. There was no problem with the stretchability here, and there was no yarn breakage after winding 100 kg.

The strong elongation curve at 90 ° C. of the obtained fiber is shown in FIG. 2 and the physical properties are shown in Table 1. The yield stress is higher than that of the conventional polylactic acid fiber (Comparative Example 1), and the mechanical properties at 90 ° C. It was greatly improved. Further, when wide-angle X-ray diffraction was performed, it was confirmed that the PET portion was oriented and crystallized. Further, when the long period was measured by small-angle X-ray scattering, it was significantly increased compared to 19 nm and 10 nm of the copolymerized PET single yarn (Reference Example 2 ). Further, when the TEM observation of the cross section of the yarn was performed, a uniform sea island structure was adopted as shown in FIG. 1, and the domain size of the island was in the submicron order in terms of diameter. Furthermore, there was a part where the sea islands were reversed, suggesting excellent compatibility. In addition, the sea-island ratio determined by image analysis is 45 area%: 55 area%, and the island ratio is much larger than 81 area%: 19 area% predicted from the preparation ratio, and polylactic acid is in the copolymerized PET domain. It seemed that the ratio of Kamijima seemed to increase after invading. Furthermore, since the long-period structure of the PET portion is 19 nm, which is approximately twice that of 10 nm of the copolymerized PET single yarn, the PET molecular chain is thought to be strongly constrained by sandwiching the polylactic acid molecular chain. .

  Further, this fiber was knitted and ironed at 180 ° C., but no hole was formed in the knitted fabric, and the heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.

Reference example 2
The copolymerized PET used in Reference Example 1 was melt spun at a spinning temperature of 280 ° C. in the same manner as in Reference Example 1, and then stretched and heat-treated at a stretching ratio of 3.0 times, a stretching temperature of 90 ° C., and a heat setting temperature of 130 ° C. An 84 dtex, 36 filament round cross-section stretched yarn was obtained. When the small-angle X-ray scattering of this was measured, the long period was 10 nm.

Reference example 3
Except that the blending ratio of the copolymerized PET was 35% by weight, spinning and drawing were performed in the same manner as in Reference Example 1 to obtain a drawn yarn having 84 dtex, 72 filaments and a round cross section. The physical property values thereof are shown in Table 1. The mechanical properties at 90 ° C. were greatly improved as compared with the conventional polylactic acid fiber (Comparative Example 1).

Reference example 4
Except that the blending ratio of copolymerized PET was 10% by weight, spinning and drawing were performed in the same manner as in Reference Example 1 to obtain a drawn yarn having 84 dtex, 144 filaments and a round cross section. The physical property values are shown in Table 1. The mechanical properties at 90 ° C. were greatly improved as compared with the conventional polylactic acid fiber (Comparative Example 1).

Reference Example 5
As specific aromatic polyester, copolymerized PET (melting point 240 ° C.) having an intrinsic viscosity of 0.55 obtained by copolymerizing 4% by weight of polyethylene glycol having a molecular weight of 1000 and further 6 mol% of isophthalic acid was used, and this had a weight average molecular weight of 200,000. Homopoly L lactic acid (optical purity 99% L lactic acid) was melt blended at 250 ° C. using a biaxial kneader to obtain a blended polyester chip. At this time, the blend ratio of the copolymerized PET was 20% by weight with respect to the blended polyester. This blended polyester chip was dried and spun and drawn in the same manner as in Reference Example 1 except that the spinning temperature was 250 ° C. to obtain a drawn yarn having a 164 dtex, 48 filaments and a round cross section. The physical property values thereof are shown in Table 1. The mechanical properties at 90 ° C. were greatly improved as compared with the conventional polylactic acid fiber (Comparative Example 1).

Example 1
As specific aromatic polyester, copolymerized PET (melting point: 225 ° C.) having an intrinsic viscosity of 0.65 obtained by copolymerizing 10 mol% of adipic acid and 6 mol% of isophthalic acid was used, and 240 of the polylactic acid used in Reference Example 5 was used. Spinning and drawing were carried out in the same manner as in Reference Example 5 except that melt blending was performed using a twin-screw kneader at 240 ° C. and the spinning temperature was 240 ° C. to obtain 84 dtex, 48 filaments and a drawn yarn having a round cross section. At this time, the blend ratio of the copolymerized PET was 20% by weight with respect to the blend polymer. The physical property values are shown in Table 1. The mechanical properties at 90 ° C. were greatly improved as compared with the conventional polylactic acid fiber (Comparative Example 1).

Comparative Example 1
The polylactic acid used in Reference 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 was applied and entangled with the yarn by the entanglement guide 7 (FIG. 4). Thereafter, the yarn was taken up by the non-heated first take-up roller 8 at a peripheral speed of 1500 m / min, and then wound around the non-heated second take-up roller 9. The undrawn yarn 11 is preheated at a first roller 13 temperature of 90 ° C., then drawn 2.8 times, heat-set at a second roller 14 at 130 ° C., and wound up through an unheated third roller 15. , 84 dtex, 24 filaments, a drawn yarn having a round cross section was obtained. The strong elongation curve at 90 ° C. is shown in FIG. 2 and the physical properties are shown in Table 1. The mechanical properties at 90 ° C. were low. Further, this fiber was knitted in a tube and subjected to an ironing test at 180 ° 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.

Comparative Example 2
A blended polyester chip was obtained by melt blending at 280 ° C. using a biaxial kneader in the same manner as in Reference Example 5 except that homo-PET having an intrinsic viscosity of 0.55 was used as the aromatic polyester. Here, the blend ratio of homo-PET was 10% by weight with respect to the blended polyester. However, since the compatibility of homo-PET and polylactic acid is poor, a clean gut cannot be produced and the chip quality is poor. Furthermore, since the melt blending temperature was too high, fuming due to decomposition of polylactic acid was observed. This blended polyester chip was dried, and melt spinning was performed at a spinning temperature of 280 ° C. in the same manner as in Reference Example 5. However, since the compatibility between homo-PET and polylactic acid was poor, rubber-like elastic behavior was strongly expressed, It was poor in spinning and could not be spun. When the ejected matter obtained here was sliced and observed by TEM, homo-PET and polylactic acid were completely phase-separated.

Comparative Example 3
Homo PBT having an intrinsic viscosity of 0.85 was used as the aromatic polyester, and melt blending with polylactic acid was performed at 250 ° C. in the same manner as in Comparative Example 2. Here, the blend ratio of the homo PBT was 10% by weight with respect to the blended polyester. However, as in Comparative Example 3, the compatibility between homo-PBT and polylactic acid was poor, so a clean gut could not be produced and the chip quality was poor. This blended polyester chip was dried and melt spun at a spinning temperature of 250 ° C. in the same manner as in Comparative Example 3. However, since the compatibility of homo-PBT and polylactic acid was poor, rubber-like elastic behavior was strongly expressed, It was poor in spinning and could not be spun. When the ejected matter obtained here was sliced and observed by TEM, homo-PET and polylactic acid were completely phase-separated.

Comparative Example 4
An example in which polymethyl methacrylate (PMMA) is blended with polylactic acid as a high Tg polymer that is completely compatible with polylactic acid at the molecular level is shown. PMMA (Sumitomo Chemical's Sumipex LG21, Tg = 105 ° C.) and the dried polylactic acid used in Reference Example 1 were melt blended at 220 ° C. using a biaxial kneader to obtain a blend polymer chip. At this time, the blend ratio of PMMA was 50% by weight with respect to the blend polymer. The Tg of this blend polymer chip was greatly improved compared to 75 ° C. and 60 ° C. of homopoly L lactic acid. This blend polymer chip was dried and melt-spun as in Reference Example 1 at a spinning temperature of 220 ° C. The undrawn yarn 11 that has been wound is preheated at a first roller 13 temperature of 90 ° C., then drawn 1.7 times, heat-set at a second roller 14 at 130 ° C., and passed through an unheated third roller 15. Winding, 100 dtex, 36 filaments, drawn yarn 16 with a round cross section was obtained. The physical properties of this yarn are shown in Table 1. The room temperature strength was low, and the mechanical properties at 90 ° C. were also low. As described above, in the completely compatible system, the Tg additivity is established, the Tg of the blend polymer is insufficiently improved, and even if the Tg becomes high, the high temperature mechanical properties are not necessarily improved.

Comparative Example 5
Homopoly L having a weight-average molecular weight of 190,000 aliphatic polyester carbonate (14% carbonate units) and a dried optical purity of 99% and a weight-average molecular weight of 200,000 polymerized by the method described in Reference Example 3 of JP-A-2000-109664 Lactic acid was melt blended at 240 ° C. using a twin-screw kneader to obtain a blend polymer chip. At this time, the blend ratio of the aliphatic polyester carbonate was 50% by weight with respect to the blend polymer. The blend polymer chip had a Tg of 65 ° C. This blend polymer chip was dried and melt spun in the same manner as in Reference Example 5 except that the spinning temperature was 240 ° C. However, because the compatibility between aliphatic polyester carbonate and polylactic acid was poor, yarn breakage occurred frequently. The undrawn yarn wound is preheated at a first roller 13 temperature of 90 ° C., then drawn 1.5 times, heat-set at 130 ° C. with a second roller 14, and wound through an unheated third roller 15. The drawn yarn 16 having 100 dtex, 36 filaments and a round cross section was obtained, but the drawability was poor and the yarn breakage occurred frequently. The physical properties of this yarn are shown in Table 1. The room temperature strength was low, and the mechanical properties at 90 ° C. were also poor.

Reference Example 6
The polylactic acid fiber having excellent high-temperature mechanical properties obtained in Reference Example 1 was subjected to friction disk false twisting at a draw ratio of 1.1 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. The CR value, which is an indicator of crimp characteristics, was 28%, which was sufficient for crimping yarns. Further, the boiling yield was 5%, which was sufficiently low.

Reference Example 7
Melt spinning was performed in the same manner as in Reference Example 1 at a spinning speed of 3000 m / min to obtain a highly oriented undrawn yarn. This was subjected to friction disk false twisting at a draw ratio of 1.5 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 index of crimp characteristics, was 25%, and the crimped yarn was sufficiently crimped. Further, the boiling yield was 5%, which was sufficiently low.

Comparative Example 6
The conventional polylactic acid fiber obtained in Comparative Example 1 was subjected to a friction disk false twisting process at a draw ratio of 1.3 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. However, the CR value, which is an index of crimp characteristics, was 10%, and there was almost no crimp. Furthermore, since the heat setting was insufficient, the boiling yield was too high at 25%.

Reference Example 8
A plain weave was prepared by using the yarn obtained in Reference Example 1 as a warp and a weft. Although warp sizing and drying were performed at 110 ° C., there was no trouble that the yarn was stretched. The obtained plain weave was scoured at 60 ° C. according to a conventional method, and then an intermediate set was applied at 140 ° C. 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.

Comparative Example 7
A plain weave was prepared using the yarn obtained in Comparative Example 1 as warp and weft. The warp paste was dried at 110 ° C., but the yarn was stretched and could not be dried.

Reference Example 9
The blend polymer obtained in Reference Example 1 was melt-spun, and this was taken up at 1600 m / min to make 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. This was hot compression molded at 220 ° C. to obtain a board having a thickness of 3 mm. This was cut into a width of 2 cm, the distance between the fulcrums was 50 cm, a 1 kg weight was placed on the center, and held at 100 ° C. for 20 minutes. After cooling, the weight was removed and the board was observed for residual warpage, but no warpage was found.

Comparative Example 8
A board was obtained in the same manner as in Reference Example 9 except that the polylactic acid used in Comparative Example 1 was used. When this was observed in the same manner as in Reference Example 9, significant residual warpage was observed.

Reference Example 10
The blended polyester chip obtained in Reference Example 1 was dried and melt-spun at 240 ° 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 condition that the first stage draw ratio is 1.4 times and the total ratio is 4.0 times, and further crimped by using a jet nozzle. Then, a bulky processed yarn for a carpet of 450 dtex, 90 filament was wound up. The number of crimps was 15 / m, indicating good crimps.

Comparative Example 9
A bulky processed yarn for carpet was obtained in the same manner as in Reference Example 10 except that the polylactic acid used in Comparative Example 1 was used. The number of crimps was 6 / m, which was insufficient.

Reference Example 11
The blended polyester chip obtained in Reference Example 1 was dried, put into a single-screw extruder equipped with a 150 mm diameter screw heated to 240 ° C., melt-extruded, and filtered in a fiber sintered stainless steel metal filter. After that, the sheet is discharged in a sheet form from a T-die, and the sheet is solidified on a cooling drum having a surface temperature of 25 ° C. at a draft ratio of 3 at a speed of 20 m / min and rapidly cooled, thereby being substantially unoriented unstretched film. Got.

  Subsequently, the unstretched film is stretched 3.5 times in the longitudinal direction of the film at a temperature of 85 ° C. using a difference in peripheral speed of the roll using a longitudinal stretching machine composed of a plurality of heated roll groups. And stretched. Thereafter, both ends of the film were gripped with clips, guided to a tenter, and stretched in the width direction of the film at a stretching temperature of 85 ° C. and a stretching ratio of 3.0. Subsequently, after heat-treating at a temperature of 160 ° C., the film edge was removed after cooling to room temperature to obtain a biaxially oriented film having a thickness of 20 μm.

  The longitudinal strength was 100 MPa, the transverse strength was 130 MPa, the longitudinal heat shrinkage was 0.5%, and the transverse heat shrinkage was 0.5%. Both strength and shrinkage were sufficient. The heat shrinkage was determined from the dimensional change when left in a dry heat 120 ° C. atmosphere for 30 minutes under no load. Further, the strength at 90 ° C. was sufficient with 45 MPa in the vertical direction and 50 MPa in the horizontal direction.

Comparative Example 10
A film was formed in the same manner as in Reference Example 11 except that the polylactic acid used in Comparative Example 1 was used. However, when heat treatment was performed at 160 ° C., a tear that was thought to be caused by partial melting of the polylactic acid occurred. The film could not be formed. Therefore, the film was formed by reducing the heat treatment temperature from 160 ° C. to 140 ° C. to obtain a biaxially oriented film having a thickness of 20 μm.

  The longitudinal strength was 110 MPa, the transverse strength was 150 MPa, the longitudinal heat shrinkage was 2.5%, and the transverse heat shrinkage was 2.5%. Although the strength was sufficient, the shrinkage became large. It was. Furthermore, the strength at 90 ° C. was remarkably inferior in high-temperature mechanical properties, with 10 MPa in the vertical direction and 13 MPa in the horizontal direction.

Reference Example 12
The blended polyester chip obtained in Reference Example 1 was dried, put into a single screw extruder equipped with a 150 mm diameter screw heated to 240 ° C., and injection molded at a cylinder temperature of 240 ° C. and a mold temperature of 40 ° C. A test piece having a length of 100 mm, a width of 20 mm, and a thickness of 3 mm was produced. The atmosphere temperature was 120 ° C., and a 1 kg weight was placed on the fulcrum distance of 80 mm for 30 minutes, but there was no residual deformation when cooled to room temperature.

Comparative Example 11
A test piece was prepared in the same manner as in Reference Example 12 except that the polylactic acid used in Comparative Example 1 was used and the extruder temperature and cylinder temperature were set to 220 ° C. The atmosphere temperature was 120 ° C., and a 1 kg weight was placed on the fulcrum at a distance of 80 mm for 30 minutes, but significant residual deformation was observed when cooled to room temperature.

Reference Example 13
Polylactic acid and polybutylene succinate used in Example 1 as the aliphatic polyester (Showa High Polymer "Bionolle" melting point 118 ° C.) a 3: 1 using a blend in which the likewise copolymerized PET as in Reference Example 1 A blended polyester chip blended with 20% by weight was prepared at 235 ° C. Then, in the same manner as in Reference Example 1, a drawn yarn having 84 dtex, 36 filaments and a round cross section was obtained. The strength at 90 ° C. was 0.7 cN / dtex, and the elongation under 0.5 cN / dtex stress was 12%, which was a sufficiently high temperature mechanical property.

Reference Example 14
A drawn yarn having 84 dtex, 36 filaments, and a round cross section was obtained in the same manner as in Reference Example 1 except that the polybutylene succinate of Reference Example 13 was used as the aliphatic polyester. The strength at 90 ° C. was 0.7 cN / dtex, and the elongation under a 0.5 cN / dtex stress was 14%, which had sufficient high-temperature mechanical properties.

Comparative Example 12
The polybutylene succinate of Reference Example 13 was melt spun at 220 ° C. in the same manner as in Comparative Example 1, and further stretched and heat-treated at a draw ratio of 2.2 times, a stretching temperature of 75 ° C., and a heat setting temperature of 85 ° C. to obtain 84 dtex, 36 A drawn yarn having a filament and a round cross section was obtained. The strength at 90 ° C. was 0.2 cN / dtex, and the high-temperature mechanical properties were extremely inferior.

It is a TEM photograph which shows the blend state of the specific aromatic polyester and aliphatic polyester in the blend polyester of this invention. It is a figure which shows the strong elongation curve in 90 degreeC of this invention and the conventional polylactic acid fiber. It is a figure which shows the strong elongation curve of the conventional polylactic acid fiber and nylon 6 fiber. It is a figure which shows a spinning and drawing apparatus.

Explanation of symbols

1: Spin block 2: Spin pack 3: Base 4: Chimney 5: Yarn 6: Converging oil supply guide 7: Entanglement 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: Stretched yarn

Claims (8)

An aromatic polyester having 2 to 15 mol% of one or more long-chain dicarboxylic acid components selected from adipic acid and sebacic acid and an aromatic polyester whose diol component is a diol having 2 carbon atoms, and having a melting point of 170 to 250 ° C. A polyester resin composition characterized in that an aliphatic polyester is blended with an aliphatic polyester in an amount of 5 to 40% by weight. The polyester resin composition of claim 1, wherein the aromatic polyester is characterized by crystalline der Rukoto.   The polyester resin composition according to claim 1 or 2, wherein the aliphatic polyester is polylactic acid.   A molded article comprising at least a part of the polyester resin composition according to claim 1.   The molded body according to claim 4, wherein the molded body is a fiber or a fiber product.   6. The shaped product according to claim 5, wherein the fiber is a crimped yarn.   The molded body according to claim 4, wherein the molded body is a film or a sheet.   The molded body according to claim 4, wherein the molded body is an injection molded body, an extrusion molded body, or a blow molded body.

Images