JP3925176B2 - Polyester resin composition - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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.
[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. Among these, a large thing is that the high-temperature mechanical properties are poor. Here, poor high temperature mechanical properties mean that the glass transition temperature (T_g) Indicates that it softens rapidly when it exceeds 60 ° C. For example, when a tensile test of polylactic acid fiber is performed at a different temperature, it 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).
[0006]
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 fibers are 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. 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. In addition, due to such troubles on the hot plate, the hot plate temperature can only be raised to 110 ° C at 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 (boiling) to a practical level of 20% or less.
[0007]
Furthermore, aliphatic polyester generally has a low melting point, and even polylactic acid, which is 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.
[0008]
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.
[0009]
[Problems to be solved by the invention]
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.
[0010]
[Means for Solving the Problems]
  Above purposeThe fatThe aliphatic polyester is blended with 5 to 40% by weight of an aromatic polyester obtained by copolymerizing 2 to 15 mol% or 2 to 15% by weight of a diol component having 6 or more carbon atoms with respect to the total amount of carboxylic acid. This is achieved by the polyester resin composition.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
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.
[0012]
The aromatic polyester referred to in the present invention means a polyester containing 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 aromatic polyester has a diol component having 6 or more carbon atoms, or that 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. Examples of the long chain dicarboxylic acid include adipic acid and sebacic acid. The copolymerization ratio is preferably 2 to 15 mol% or 2 to 15% by weight based on the total amount of carboxylic acid in the case of diol and the total amount of diol in the case of dicarboxylic acid. For convenience, 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 to be used in the present invention will be simply specified below. Of aromatic polyester ”.
[0013]
Furthermore, since the melting point of the aliphatic polyester is generally 170 ° C. or lower, considering that the blending temperature should be lowered as much as possible, it is possible to lower the melting point by further copolymerizing a specific aromatic polyester with isophthalic acid or the like. preferable. The melting point of the specific aromatic polyester is preferably 250 ° C. or lower, more preferably 230 ° C. or lower. However, the melting point of the specific aromatic polyester is preferably 170 ° C. or higher, more preferably 200 ° C. or higher, from the viewpoint of improving the heat resistance of the blend polyester resin in which the specific aromatic polyester is blended with the aliphatic polyester or a molded product thereof. It is.
[0014]
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 the differential scanning calorimeter (DSC) measurement, it can be determined that the polymer is crystalline.
[0015]
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.
[0016]
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.
[0017]
For this, crystallization of certain aromatic polyesters or high T_gIs preferably used. Also, crystallization or high T_gIn order to sufficiently exhibit the effect, 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.
[0018]
For example, in the blended fiber system of polylactic acid 80% by weight and copolymerized PET 20% by weight shown in Example 1, the sea-island ratio obtained by TEM observation (FIG. 1) is 45 area%: 55 area%, and the charging ratio Compared with the predicted area ratio of 81% by area to 19% by sea 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 Example 1, it is 19 nm, which is about twice as long, and it can be interpreted that the copolymerized PET molecular chain partially sandwiches the polylactic acid molecular chain.
[0019]
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._gT as a blended polyester due to the additivity of_gIn 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.
[0020]
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 is virtually impossible.
[0021]
Thus, in order to achieve both high-temperature mechanical properties and moldability, the so-called blended state has a sea-island structure, and the island domain size is at least partly 0.001 to 10 μm in terms of diameter. It is preferable. In particular, in the case of fibers and films, it is preferable that at least 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 Example 1 described above, such a state can be observed in the fiber inner layer portion (FIG. 1).
[0022]
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.
[0023]
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. Further, it is preferable that the elongation of the fiber of the present invention at room temperature is 15 to 70%, since the process passability when making the fiber product is improved. The elongation at room temperature is more preferably 25 to 50%.
[0024]
In the polylactic acid fiber which is a representative example of the aliphatic polyester, as described above, at 90 ° C., it becomes a strong elongation curve shape (FIG. 3) close to flow, and the strength becomes 0.5 cN / dtex or less. The fiber of the present invention can raise the strength to 0.7 cN / dtex or more even at 90 ° C., and the creep characteristics can be greatly improved. As the creep property, 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, elongation at 90 ° C under 0.5cN / dtex stress is obtained by conducting a tensile test on the fiber at 90 ° C and reading the elongation at a stress of 0.5cN / dtex in the strong elongation curve diagram. (Fig. 2). The elongation at 90 ° C. under 0.5 cN / dtex stress is preferably 10% or less. Further, if the strength at 90 ° C. is 0.7 cN / dtex or more, the strength at high temperature of the fiber product made of polylactic acid fiber can be improved, which is preferable. The strength at 90 ° C. is more preferably 1.0 cN / dtex or more.
[0025]
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 3-10%.
[0026]
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.
[0027]
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.
[0028]
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.
[0029]
【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.
[0030]
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 GPC, and the weight average molecular weight was calculated in terms of polystyrene.
[0031]
B. Intrinsic viscosity of aromatic polyester [η]
Measured in orthochlorophenol at 25 ° C.
[0032]
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.
[0033]
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, and the elongation at 0.5 cN / dtex was read to determine the elongation at 90 ° C. under a 0.5 cN / dtex stress.
[0034]
E. Strength at 90 ° C
At a measurement temperature of 90 ° C., a strong elongation curve was obtained in the same manner as D above, and the load value was divided by the initial fineness to obtain the strength at 90 ° C.
[0035]
F. Boiling
Boiling (%) = [(L0-L1) / L0)] x 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
G. Polymer T_gAnd melting point
T with 2nd run using PERKIN ELMER DSC-7_gAnd the melting point was measured. At this time, the sample weight was 10 mg, and the temperature elevation rate was 16 ° C./min.
[0036]
H. Observation of blended state of blended polyester
An ultrathin slice was cut in the cross-sectional direction of the blended fiber, and the blended state of the polyester was observed with a transmission electron microscope (TEM).
[0037]
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. The sea-island ratio was calculated using image analysis software.
[0038]
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.
[0039]
X-ray source: Cu-Kα ray (Ni filter)
Output: 40kV x 20mA
Slit: 2mmφ-1 ° -1 °
Detector: Scintillation counter
Counting recording device: RAD-C type manufactured by Rigaku Corporation
Step scan: 0.05 ° step
Integration time: 2 seconds
J. et al. Small angle X-ray scattering
A small angle X-ray scattering photograph was taken using a RU-200 type X-ray generator manufactured by Rigaku Corporation.
[0040]
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
The long period was calculated from the distance r (mm) between the scattering points on the photograph using the Bragg equation.
[0041]
    J = λ / 2sin [{tan^-1(r / R)} / 2]
    J: Long period (nm)
    R: Camera radius (405mm)
    λ: X-ray wavelength (0.15418 nm)
  K. Crimp characteristics and CR value of false twisted yarn
  The false twisted yarn was scraped off, 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. Then underwaterso 0The skein length L′ 1 after 2 minutes was measured after exchanging with a fine load equivalent to .0018 cN / dtex (2 mgf / d). And CR value was calculated by the following formula.
[0042]
CR (%) = [(L'0-L'1) / L'0] x 100 (%)
L. Number of crimps of crimped yarn
The crimped yarn was freely shrunk in 100 ° C hot water in a substantially load-free state, and then the number of crimps was counted.
[0043]
Example 1
As a specific aromatic polyester, a copolymer 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, and this and a homopoly L having a weight average molecular weight of 150,000 are used. 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 blending ratio of the copolymerized PET was 20% by weight with respect to the blended polyester. T of this blend polyester chip_gWas approximately equal to 61 ° C. and 60 ° C. for 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 90 ° C on the first roller 13 and then stretched 2.8 times, heat-set at 130 ° C on the second roller 14, wound up through the non-heated third roller 15, 84 dtex, 36 filaments A drawn yarn 16 having a round cross section was obtained. There was no problem with the stretchability here, and there was no yarn breakage after 100 kg winding.
[0044]
The strength elongation curve of the obtained fiber at 90 ° C 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 are 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 with 19 nm and 10 nm of the copolymerized PET single yarn (Reference Example 1). Further, when TEM observation of the cross section of the yarn was performed, a uniformly distributed 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 a copolymerized PET domain. It seemed that the ratio of Kamijima seemed to increase after invading. Furthermore, since the long-period structure of the PET part is 19 nm, which is about twice that of the copolymerized PET single thread of 10 nm, the PET molecular chain is thought to be strongly constrained by sandwiching the polylactic acid molecular chain. .
[0045]
Furthermore, this fiber was knitted and ironed at 180 ° C. However, there was no hole in the knitted fabric, and heat resistance was significantly improved compared to the conventional polylactic acid fiber (Comparative Example 1). It was.
[0046]
Reference example 1
The copolymerized PET used in Example 1 was melt spun at a spinning temperature of 280 ° C. in the same manner as in 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., 84 dtex, A 36 filament round cross-section drawn yarn was obtained. When the small-angle X-ray scattering was measured, the long period was 10 nm.
[0047]
Example 2
Except that the blending ratio of the copolymerized PET was 35% by weight, spinning and drawing were carried out in the same manner as in 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 significantly improved as compared with the conventional polylactic acid fiber (Comparative Example 1).
[0048]
Example 3
Except that the blending ratio of copolymerized PET was set to 10% by weight, spinning and drawing were carried out in the same manner as in 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).
[0049]
Example 4
As a specific aromatic polyester, a 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 6 mol% of isophthalic acid, and this is homopoly L having a weight average molecular weight of 200,000. 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 blending ratio of the copolymerized PET was 20% by weight with respect to the blended polyester. This blended polyester chip was dried, and spinning and drawing were carried out in the same manner as in Example 1 except that the spinning temperature was 250 ° C. to obtain a drawn yarn having 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 significantly improved as compared with the conventional polylactic acid fiber (Comparative Example 1).
[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 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 was 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, wound through an unheated third roller 15, and 84 dtex , 24 filaments, 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 and ironed 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.
[0052]
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 Example 4 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, the compatibility between homo-PET and polylactic acid was poor, so a clean gut could not be produced and the chip quality was 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 spun at a spinning temperature of 280 ° C. in the same manner as in Example 4. However, because of the poor compatibility of homo-PET and polylactic acid, rubber-like elastic behavior was strongly developed, and It was poor in spinning and could not be spun. When the ejected material obtained here was sliced and observed by TEM, homo-PET and polylactic acid were completely phase-separated.
[0053]
Comparative Example 3
A homo-PBT having an intrinsic viscosity of 0.85 was used as the aromatic polyester and melt blended with polylactic acid at 250 ° C. in the same manner as in Comparative Example 2. Here, the blend ratio of 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 was not 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, because of the poor compatibility between homo-PBT and polylactic acid, rubber-like elastic behavior was strongly developed, and the kite yarn It was poor in spinning and could not be spun. When the ejected material obtained here was sliced and observed by TEM, homo-PET and polylactic acid were completely phase-separated.
[0054]
Comparative Example 4
High T completely compatible with polylactic acid at the molecular level_gAn example in which polymethyl methacrylate (PMMA) is blended with polylactic acid as a polymer is shown. PMMA (Sumitomo Chemical's Sumipex LG21, T_g= 105 ° C.) and dried, the polylactic acid used in Example 1 was melt blended at 220 ° C. using a twin-screw 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. T of this blend polymer chip_gWas significantly improved compared to 75 ° C. and 60 ° C. of homopoly L-lactic acid. This blend polymer chip was dried and melt-spun as in Example 1 at a spinning temperature of 220 ° C. The pre-stretched unwound yarn 11 is preheated at a first roller 13 temperature of 90 ° C., then drawn by 1.7 times, heat-set at a second roller 14 at 130 ° C., and wound through an unheated third roller 15. , 100 dtex, 36 filament, drawn yarn 16 having 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. In this way, in the completely compatible system, T_gT of blend polymer_gInsufficient improvement and high T_gEven if it became, it did not necessarily lead to the improvement of high-temperature mechanical characteristics.
[0055]
Comparative Example 5
Polymerized by the method described in Example 2 of JP-A-2000-109664, aliphatic polyester carbonate having a weight average molecular weight of 190,000 (carbonate unit is 14%), dried optical purity 99%, and homopoly L having a weight average molecular weight of 200,000 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. T of this blend polymer chip_gWas 65 ° C. This blend polymer chip was dried and melt spun in the same manner as in Example 4 except that the spinning temperature was 240 ° C. However, the thread breakage occurred frequently because the compatibility between the aliphatic polyester carbonate and polylactic acid was poor. The pre-wound unwound yarn is preheated at the first roller 13 temperature of 90 ° C., then drawn 1.5 times, heat-set at 130 ° C. with the second roller 14, and wound through the unheated third roller 15, Although a drawn yarn 16 having 100 dtex, 36 filaments and a round cross section was obtained, 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.
[0056]
[Table 1]
Example 6
The polylactic acid fiber having excellent high-temperature mechanical properties obtained in 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 index of crimp characteristics, was 28%, which was sufficient for crimped yarn. Further, the boiling yield was 5%, which was sufficiently low.
[0057]
Example 7
Melt spinning was carried out at a spinning speed of 3000 m / min in the same manner as in Example 1 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%, which was sufficient as a false twisted yarn. Further, the boiling yield was 5%, which was sufficiently low.
[0058]
Comparative Example 6
The conventional polylactic acid fiber obtained in Comparative Example 1 was subjected to friction disk false twisting at a draw ratio of 1.3 times, a heater temperature of 130 ° C., and a processing speed of 400 m / min. It was. 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 yarn. However, the CR value, which is an index of crimp characteristics, was 10% and there was almost no crimp. Furthermore, the boiling point was too high at 25% due to lack of heat setting.
[0059]
Example 8
A plain weave was prepared using the yarn obtained in Example 1 as warp and weft. The warp sizing and drying was performed at 110 ° C., but 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.
[0060]
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.
[0061]
Example 9
The blend polymer obtained in Example 1 was melt-spun, taken up at 1600 m / min to make a tow, and stretched 4 times in a 90 ° C. water bath. Then, after passing through a 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 3 mm thick board. 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.
[0062]
Comparative Example 8
A board was obtained in the same manner as in Example 9 except that the polylactic acid used in Comparative Example 1 was used. When this was observed in the same manner as in Example 9, significant residual warpage was observed.
[0063]
Example 10
The blended polyester chip obtained in 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 stretched in two stages under the condition that the first stage draw ratio is 1.4 times and the total ratio is 4.0 times, and further crimped using a jet nozzle and then 450 dtex Rolled up bulky yarn for 90-filament carpets. The number of crimps was 15 / m, indicating good crimps.
[0064]
Comparative Example 9
A bulky processed yarn for carpet was obtained in the same manner as in Example 10 except that the polylactic acid used in Comparative Example 1 was used. The number of crimps was 6 / m, which was insufficient.
[0065]
Example 11
The blended polyester chip obtained in 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 metal filter. After that, the sheet is discharged from a T-die into a sheet shape, and the sheet is solidified and rapidly cooled on a cooling drum having a surface temperature of 25 ° C. at a draft ratio of 3 at a speed of 20 m / min. Got.
[0066]
Subsequently, the unstretched film is stretched at a magnification of 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 by using a longitudinal stretching machine composed of a plurality of heated roll groups. did. Thereafter, both ends of the film were held with clips and led 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. Next, heat treatment was performed at a temperature of 160 ° C., and after cooling to room temperature, the film edge was removed to obtain a biaxially oriented film having a thickness of 20 μm.
[0067]
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 obtained 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 sufficiently high at 45 MPa in the vertical direction and 50 MPa in the horizontal direction.
[0068]
Comparative Example 10
A film was formed in the same manner as in 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 might be caused by partial melting of 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.
[0069]
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 increased. Furthermore, the strength at 90 ° C was 10MPa in the longitudinal direction and 13MPa in the lateral direction.
[0070]
Example 12
The blended polyester chip obtained in 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 ambient temperature was 120 ° C, and a 1 kg weight was placed for 30 minutes at a fulcrum distance of 80 mm, but there was no residual deformation when cooled to room temperature.
[0071]
Comparative Example 11
A test piece was prepared in the same manner as in 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 ambient 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.
[0072]
Example 13
As the aliphatic polyester, a blend of polylactic acid and polybutylene succinate used in Example 1 (Showa High Polymer “Bionore” melting point 118 ° C.) at a ratio of 3: 1 was used. A blended polyester chip blended with 20% by weight was prepared at 235 ° C. And in the same manner as in Example 1, 84 dtex, 36 filaments, drawn yarn having a round cross section was obtained. The strength at 90 ° C was 0.7cN / dtex, and the elongation under 0.5cN / dtex stress was 12%.
[0073]
Example 14
Except for using polybutylene succinate of Example 13 as the aliphatic polyester, a drawn yarn having 84 dtex, 36 filaments, and round cross section was obtained in the same manner as in Example 1. The strength at 90 ° C was 0.7 cN / dtex, and the elongation under 0.5 cN / dtex stress was 14%.
[0074]
Comparative Example 12
The polybutylene succinate of Example 13 was melt-spun at 220 ° C. 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 filaments, A drawn yarn having a round cross section was obtained. The strength at 90 ° C was 0.2 cN / dtex, which was extremely inferior in high-temperature mechanical properties.
[0075]
【The invention's effect】
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.
[Brief description of the drawings]
FIG. 1 is a TEM photograph showing a blend state of a specific aromatic polyester and aliphatic polyester in a blended polyester of the present invention.(FIG. 1A is a copy of a TEM photograph, and FIG. 1B is a TEM photograph.)
FIG. 2 is a diagram showing a strong elongation curve at 90 ° C. of the present invention and a conventional polylactic acid fiber.
FIG. 3 is a diagram showing the strength and elongation curves of conventional polylactic acid fibers and nylon 6 fibers.
FIG. 4 is a view showing a spinning and drawing apparatus.
[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 (8)

  The aliphatic polyester is blended with 5 to 40% by weight of an aromatic polyester obtained by copolymerizing 2 to 15 mol% or 2 to 15% by weight of a diol component having 6 or more carbon atoms with respect to the total amount of carboxylic acid. A polyester resin composition. Aromatic polyester is crystalline, polyester resin composition according to claim 1 Symbol placement, wherein the melting point of 170 to 250 ° C.. The polyester resin composition of claim 1 Symbol placement, wherein the aliphatic polyester is polylactic acid. Shaped body, characterized in that it comprises at least a portion of the polyester resin composition of claim 1 Symbol placement. 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.