JP2009293044A - Polyglygolic acid-based resin composition and molded article of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyglycolic acid-based resin composition and a molded article of the same in which while excellent properties of a polyglycolic acid resin typified by a gas barrier property are maintained, moisture-resistance stability and a hot-melt processing property are improved, and further transparency is improved. <P>SOLUTION: The polyglycolic acid resin composition is produced by blending comparatively a small amount of an aromatic polyester resin into the polyglycolic acid resin, and the molded article having the improved transparency by stretching through the improved stretchability thereof is produced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyglycolic acid resin composition containing a polyglycolic acid resin as a main component and a relatively small amount of an aromatic polyester resin, and a molded product thereof.

  Polyglycolic acid (including PGA and polyglycolide) is excellent in heat resistance, gas barrier properties, rigidity (mechanical properties as a packaging material), etc. in addition to biodegradability, so various sheets, films, containers, New applications are being developed as molding materials such as injection molded products (Japanese Patent Laid-Open Nos. 10-60136, 10-80990, 10-138371, 10-337772, ). However, since the polyglycolic acid resin exhibits hydrolyzability, a molding material with improved characteristics is desired by combining with other thermoplastic resin materials rather than use as a molding material alone. is there.

  On the other hand, an aromatic polyester resin, which is a polycondensation product composed of an aromatic dicarboxylic acid typified by (tere) phthalic acid and a diol, is excellent in transparency, rigidity and easy moldability, and is a typical example of polyethylene terephthalate. A so-called “PET bottle” including (PET) as a representative material name is widely used for drinking bottles. Such drinking bottles are required to have an oxygen barrier property for preventing the deterioration of the contents and a carbon dioxide gas barrier property for preventing the escape of carbon dioxide gas dissolved in the sparkling beverage under pressure, thereby improving the gas barrier property. It is desired.

  Therefore, the above-described polyglycolic acid resin and aromatic polyester resin are combined or mixed to form a molding material with excellent mechanical properties and gas barrier properties as a packaging material using the polyglycolic acid resin. Attempts have also been made to obtain composite materials suitable as materials, particularly packaging or container molding materials.

  For example, Barbee, U.S. Pat. No. 4,424,242, discloses a multilayer packaging material comprising a laminate of a pressed polyglycolic acid film and a polyester terephthalate film. Barbee US Pat. No. 4,565,851 also discloses a polymer blend comprising polyglycolic acid and an aromatic polyester resin in a blend ratio of 50/50 to 5/95 on a weight basis.

  However, among the composite materials described above, the laminate is poor in melt processing characteristics and stretching characteristics. Further, polymer blends whose polyglycolic acid content exceeds 25% by weight are not subject to evaluation by stretching. Furthermore, each composite material uses an aromatic polyester resin as a main component, and its gas barrier property is intended to be improved with a relatively small amount of polyglycolic acid resin, making full use of the excellent properties of polyglycolic acid resin. It ’s hard to say.

  The main object of the present invention is to provide a thermoplastic resin composition comprising a polyglycolic acid resin as a main component, improved in moisture resistance stability, stretchability and hot-melt processing characteristics, and excellent in gas barrier properties, and a molded product thereof. There is to do. A further object of the present invention is to provide a polyglycolic acid resin composition having improved gas barrier properties and transparency and a molded product thereof.

  According to the present invention, a polyglycolic acid resin containing a pre-added heat stabilizer in an amount exceeding 50% by weight, an aromatic dicarboxylic acid that can be substituted with an aliphatic dicarboxylic acid up to 15 mol%, and a diol, A polyglycolic acid resin composition comprising: an aromatic polyester resin having an intrinsic viscosity of 0.6 to 2.0 dl / g measured in a mixed solvent of tetrachloroethane (1/1) at 25 ° C. and less than 50% by weight. Is provided.

  The composition described in the above-mentioned Barbee US Pat. No. 4,565,851 is based on the idea of improving the gas barrier properties of an aromatic polyester resin by incorporating a small amount of polyglycolic acid. A resin composition containing the main component has not been studied. In contrast, the present invention improves the moisture resistance stability and thermal solvent processing characteristics of a polyglycolic acid resin as a main component by blending a relatively small amount of an aromatic polyester resin. The effect of adding such a small amount of aromatic polyester resin, which forms the basis of the present invention, cannot be obtained by blending polyamide, polyethylene, and polylactic acid used as representatives of other thermoplastic resins (Example 28 described later). ~ 30).

  Conventionally, a thermoplastic resin composition comprising a polyglycolic acid resin in a superior amount (a proportion exceeding 50% by weight) and an inferior amount (less than 50% by weight) of an aromatic polyester resin as in the present invention has not been put into practical use. Although the reason is not necessarily clear, according to the study by the present inventors, it is considered that the following factors hindered the practical use of such a polyglycolic acid resin composition. (A) Polyglycolic acid has a low thermal decomposition temperature of about 245 ° C., and it was considered difficult to perform mixed hot melt processing with an aromatic polyester resin that requires a hot melt processing temperature of 240 to 270 ° C. (B) The blend of polyglycolic acid resin and aromatic polyester resin is not a completely hot melt compatible system, and the refractive index is different, so that the molded product is whitened, and it is difficult to obtain favorable transparency for the packaging material (for example, see below) As shown in Example 8, a molded sheet of a 50:50 (weight) blend of both exhibits a haze of 90% and is very poor in transparency). (C) It was considered that the stretchability of the molded product deteriorated as the polyglycolic acid content increased.

  However, according to further studies by the present inventors, the problem of thermal stability of the polyglycolic acid resin (a) can be improved at least by blending an appropriate thermal stabilizer. It has been found that there is no problem in mixed heat melting with resin. It was also found that the blending of a small amount of aromatic polyester resin significantly contributes to the improvement of hot melt processing characteristics and moisture resistance stability and (c) stretchability of the main component polyglycolic acid resin. . Furthermore, it has been found that the problem of (b) whitening of the molded product can be significantly reduced by extending the molded product by utilizing the improved stretchability, and the transparency is significantly improved. Thereby, the gas barrier property as a packaging material is also improved. The blending of a small amount of the aromatic polyester resin contributes to the improvement of the stretchability, and the improvement of the transparency of the molded product by the above-mentioned stretching is not recognized with the polyglycolic acid resin alone, but the aromatic polyester. It is recognized for the first time in the resin composition of the present invention containing a resin.

  The polyglycolic acid-based resin composition of the present invention and the molded product thereof are based on the knowledge of the inventors as described above.

(Polyglycolic acid resin)
The polyglycolic acid resin (hereinafter often referred to as “PGA resin”), which is the main component of the polyglycolic acid resin composition of the present invention (hereinafter often referred to as “PGA composition”), has the following formula (I):

  Examples of comonomers that give a polyglycolic acid copolymer together with glycolic acid monomers such as glycolide include ethylene oxalate (that is, 1,4-dioxane-2,3-dione), lactides, and lactones (for example, β-propiolactone, β-butyrolactone, β-pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, etc.), carbonates (eg, trimethyline carbonate, etc.), ethers Cyclic monomers such as ether esters (such as dioxanone), amides (such as ε-caprolactam); lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid Hydroxycal such as 6-hydroxycaproic acid Acids or alkyl esters thereof; substantially equimolar mixtures of aliphatic diols such as ethylene glycol and 1,4-butanediol with aliphatic dicarboxylic acids such as succinic acid and adipic acid or alkyl esters thereof; Or 2 or more types of these can be mentioned.

  The glycolic acid repeating unit in the PGA resin is 55% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. When this ratio is too small, the gas barrier property improvement effect expected for the PGA resin becomes poor. As long as this is the case, the PGA resin may be used in combination of two or more polyglycolic acid (co) polymers.

  The polyglycolic acid-based resin composition (PGA composition) of the present invention contains the PGA resin in a dominant amount, that is, in a proportion exceeding 50% by weight. The PGA resin content in the PGA composition is preferably 60 to 99% by weight, more preferably 60 to 90% by weight, and still more preferably 70 to 90% by weight. As the amount of PGA resin decreases, the gas barrier property improving effect becomes poor. On the other hand, when it exceeds 99% by weight, the moisture resistance stability and the effect of improving hot melt processing characteristics, and further the effect of improving stretchability due to the blending of the aromatic polyester resin become poor. Further, the PGA composition of the present invention preferably contains 50% by weight or more, more preferably 70% by weight or more of the glycolic acid repeating unit represented by the above formula (I).

  The PGA resin preferably has a weight average molecular weight (in terms of polymethyl methacrylate) in the range of 50,000 to 600,000 in GPC measurement using a hexafluoroisopropanol solvent. When the weight average molecular weight is too low, it is difficult to melt and mix with the aromatic polyester resin, and the strength of the molded product is lowered. If the weight average molecular weight is too large, it is difficult to melt and mix with the aromatic polyester resin, heat is generated by the shearing force of the screw during melt processing, and when the PGA composition is processed into pellets or when processed into a molded product, Resin coloring progresses, and spots due to poor melting (flow mark of the molded product) occur, resulting in poor appearance. A weight average molecular weight of about 150,000 to 300,000 is more preferable.

(Aromatic polyester resin)
The aromatic polyester resin that is the second component of the PGA composition of the present invention is a polyester in which the dicarboxylic acid that constitutes the polyester and the dicarboxylic acid that is one of the diols are aromatic. As the aromatic dicarboxylic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like are preferable. The aromatic dicarboxylic acid may be copolymerized with an aromatic carboxylic acid compound having 3 or more carboxyl groups and an aliphatic or alicyclic carboxylic acid compound having 2 or more carboxyl groups. On the other hand, examples of preferred diol components include ethylene glycol, propylene glycol, 1,4-butanediol, xylylene glycol, bisphenol A, diethylene glycol, 1,4-cyclohexanedimethanol, 2-methyl-1,3-propanediol. More preferably, it contains a diol component having 6 or less carbon atoms such as neopentyl glycol. Examples of particularly preferred aromatic polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT), and at least one of dicarboxylic acid and diol is composed of two components. Copolyester (co-PET), for example, co-condensate of terephthalic acid as dicarboxylic acid with ethylene glycol (60-75 mol%) and 1,4-cyclohexanedimethanol (25-40 mol%) as diol And a polyester using terephthalic acid as a dicarboxylic acid, a part of the terephthalic acid, up to about 15 mol% of other carboxylic acid, for example, isophthalic acid or an aliphatic or alicyclic ring having two or more carboxyl groups Family carvone Copolyesters obtained by replacing in the compound is also preferably used. An aromatic polyester or copolymer polyester containing a diol component having 6 or less carbon atoms improves and maintains both transparency and gas barrier properties in combination with a PGA resin.

The aromatic polyester resin is used in the PGA composition of the present invention in an amount of 1% by weight or more and less than 50% by weight, preferably 40% by weight or less, more preferably 30% by weight or less. Even if it is 1% by weight or more, the moisture resistance stability of the PGA composition and the stretchability improving effect of the molded product obtained from the composition can be obtained. It is preferable to make further improvements.
On the other hand, when it is contained in an amount of 50% by weight or more, the oxygen gas permeability increases as compared with the case of the PGA resin alone, and the remarkable improvement effect of the gas barrier property is obtained by using the PGA resin as the main object of the present invention as a main component. It becomes impossible. The required level of gas barrier properties is determined depending on the application, but in order to maintain good gas barrier properties, the proportion of the aromatic polyester resin in the PGA composition is preferably 40% by weight or less, and more preferably in the PGA composition. It is preferable to set the PGA resin content in the range of 90 to 70% by weight in order to achieve both transparency and gas barrier properties.

  The PGA composition of the present invention can include a recycled product of an aromatic polyester resin (and PGA resin). For example, a PGA resin is added to maintain the composition range of the PGA composition of the present invention. Can be mixed. Moreover, in order to obtain a colored molded product, a colored molded product having a desired concentration can be easily obtained by previously mixing a colorant such as a pigment in the PGA resin and / or the aromatic polyester resin.

  The aromatic polyester resin preferably has an intrinsic viscosity (intrinsic viscosity, IV value) measured in a phenol / tetrachloroethane (1/1) mixed solvent at 25 ° C. in the range of 0.6 to 2.0 (dl / g). When the IV value is too low, it becomes difficult to form the composition into a film, and the film strength tends to be lowered. If the IV value is too large, spots due to resin coloring or poor melting are likely to occur due to shear heat generation during melt processing. More preferably, the IV value is in the range of 0.7 to 1.5.

  In the PGA composition of the present invention, it is preferable that the melt viscosity at the time of molding of the PGA resin and the aromatic polyester resin is close. A preferred viscosity ratio is in the range of 1/10 to 10/1, which facilitates molding.

(Other thermoplastic resins)
As described above, the PGA composition of the present invention includes the above-described PGA resin in an amount exceeding 50% by weight and the aromatic polyester resin in an amount of 1% by weight or more, preferably 10% by weight or more. The purpose is to improve moisture resistance stability and hot melt processing characteristics while maintaining the excellent gas barrier properties of PGA resin, and to improve the stretchability and transparency of the molding. And Therefore, as long as it does not contradict such purpose, other thermoplastic resins can be included in the PGA composition of the present invention as long as the contents of the PGA resin and the aromatic polyester resin are maintained. Examples of such other thermoplastic resins include homomonomers or copolymers that give the above-described polyglycolic acid copolymer.

(Heat stabilizer)
The PGA composition of the present invention preferably contains a heat stabilizer. As the heat stabilizer, it can be selected and used from among the processed materials conventionally known as antioxidants for polymers. Among them, a heavy metal deactivator, a pentaerythritol skeleton structure represented by the following formula (II) ( Or a phosphate ester having a cyclic neopentanetetrayl structure), a phosphorus compound having at least one hydroxyl group and at least one alkyl ester group represented by the following formula (III), and a metal carbonate: At least one compound is preferably used. In particular, a phosphate ester having a pentaerythritol skeleton structure (or cyclic neopentanetetrayl structure) represented by the following formula (II), at least one hydroxyl group and at least one alkyl ester group represented by the following formula (III): Since the phosphorus compound which has has the effect of improving a thermal stability effectively by addition of a small amount, it is preferable.

  The heat stabilizer is mixed in advance with the step of pelletizing the PGA resin, melt-mixed with the aromatic polyester resin, or melt-mixed when the PGA resin and the aromatic polyester resin are made into a PGA composition, etc. The method can be used. If a PGA resin is previously melt-mixed with a heat stabilizer, the heat stability is effectively improved with a small amount of heat stabilizer. This is because the crystal melting point of the aromatic polyester resin is considerably higher than that of the PGA resin, so that it is preferable to increase the stability during heat-melt mixing in advance.

  The blending ratio of the heat stabilizer is usually 0.001 to 5 parts by weight, preferably 0.003 to 3 parts by weight, and more preferably 0.005 to 1 part by weight with respect to 100 parts by weight of the PGA resin. The amount is usually about 0.0001 to 2.5 parts by weight with respect to 100 parts by weight of the PGA composition. When there is too much addition amount of a heat stabilizer, while the addition effect is saturated, transparency may be inhibited.

(Molding)
In addition to the PGA resin and aromatic polyester resin described above, the PGA composition of the present invention preferably containing a heat stabilizer has improved heat-melt processing characteristics, so that films, sheets, fibers, and other extruded products are obtained. It can be easily molded into various molded products such as injection molded products and hollow molded products. A film or sheet is generally produced by extruding a pellet made of a PGA composition from a flat die such as a T die or a circular die. As the film, a stretched film or a heat-shrinkable film is preferable. The sheet can be secondarily formed into a container such as a tray or a cup by a sheet forming method such as vacuum forming or pressure forming. Examples of the hollow molded product include a blow container and a stretch blow container.

  The molded product of the present invention is preferably stretched by an aspect such as film stretching, vacuum or pressure sheet molding or stretch blow molding. This is because, as described above, first, the molded product of the PGA composition of the present invention is improved in stretchability by blending 1% by weight or more of an aromatic polyester resin and secondly, This is because the gas barrier property and transparency suitable as a packaging or container material are improved by stretching the molded article by utilizing the improved stretching. The draw ratio is preferably at least twice in one direction, more preferably about 3 to 4 times, and an area ratio of about 9 to 16 times. For example, if the draw ratio is excessively increased to a level exceeding 30 times, the gas barrier property may be lowered.

  The molded product of the present invention including a film, sheet or container form may be a single layer, but can be laminated with other resin layers, paper, or the like, if necessary. Lamination methods include laminating, coating and coextrusion. A dry process such as aluminum deposition can also be applied.

  Laminating includes wet lamination, dry lamination, extrusion lamination, hot melt lamination, non-solvent lamination and the like. Coating includes a method of applying a moisture-proof coat or moisture-proof laminate to the surface of the stretched film.

  In the lamination by coextrusion, it is preferable to arrange the other resin layers on both sides of the composition layer of the present invention as an intermediate layer. You may arrange | position an adhesive layer between each layer as needed. In the case of stretching after coextrusion, the entire laminate is stretched. Therefore, a thermoplastic resin that can be easily stretched is selected as the other resin. For other resin layers, depending on the desired function, for example, a resin that can be sealed, impact resistance, abuse resistance (abuse durability), heat resistance (eg, boil resistance, retort resistance), etc. An excellent resin can be disposed. The other resin layers can be made into a plurality of layers as desired.

  More specifically, examples of preferable other thermoplastic resins constituting one layer laminated with the PGA composition of the present invention include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyolefin resins such as polyethylene, Polystyrene resins, acrylic acid or methacrylic acid resins, nylon resins, sulfide resins such as polyphenylene sulfide, and polycarbonate resins are used. Among them, polyester resins, particularly aromatic polyester resins in which at least one of a diol component and a dicarboxylic acid component, preferably dicarboxylic acid, is aromatic, satisfy both desired transparency and gas barrier properties depending on the application. It is preferably used to give a multilayer molded body.

  The thickness of the molded product of the present invention including the film, sheet or container form is selected from the range of 5 to 1000 μm in consideration of the strength, transparency and gas barrier properties depending on the application. The thickness of the PGA composition layer in the multilayered molded product is preferably 3 to 90% with respect to the thickness of the entire molded product. If it is less than 3%, the contribution of the PGA composition layer to the improvement of the gas barrier property of the molded product is poor, and if it exceeds 90%, it may be difficult to maintain transparency.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. The following measurements were made for evaluation.

(Thickness structure of film and sheet)
The thickness structure of the film or sheet was measured using “Layer Gauge II” manufactured by Topwave Co., Ltd.

(Extensible)
The stretchability was determined as “A” when the transparency of the molded product hardly deteriorated due to stretching, and “C” when it decreased. This is because the decrease in transparency occurs when the stretchability is poor.

(Moisture resistance stability)
The humidity resistance stability was determined by the presence or absence of the occurrence of “cracks” when stored at 80 ° C. and 95% relative humidity for 6 hours and 12 hours, respectively. “A” indicates no occurrence of “crack” in 12 hours, “crack” occurs in 12 hours, “B” indicates no occurrence of “crack” between the 6th order, and “crack” occurs in 6 hours. In the case where the occurrence of the error occurred, “C” was assigned.

(transparency)
As the haze% representing the degree of transparency, a value obtained by applying glycerin to the sample surface using a “haze meter” manufactured by Tokyo Denshoku Co., Ltd. and eliminating the influence of the sample surface was used. The smaller the haze%, the better the transparency.

(Oxygen gas barrier properties)
The oxygen gas barrier property was measured using “OX-TRAN100” manufactured by Mocon under the condition of 23 ° C. and relative humidity of 80%. The oxygen gas permeation amount in units of cc / m ² / day / atm normalized with a thickness of 20 μm was measured.

(Preparation of PGA composition)
PGA (manufactured by Kureha Chemical Co., Ltd., 270 ° C., shear rate: melt viscosity at 121 / s = 920 Pa · s) and heat stabilizer (Asahi Denka Co., Ltd., cyclic neopentanetetraylbis (octadecyl) phosphite) (II) And a copolymerized PET (hereinafter referred to as “co-PET”; “PET-DA5” manufactured by Kanebo Synthesis Co., Ltd.). , Composition: terephthalic acid / dimer acid / ethylene glycol = 95/5/100 (mol / mol / mol) copolymer; IV = 0.74) were mixed in the ratio shown in Table 1 below. The mixture was melt processed with a 20φ twin screw extruder (cylinder temperature: 240 to 270 ° C., the temperature distribution being C1 / C2 / C3 / D = 240/250/270/250 ° C.) to obtain pellets Pe1 to Pe9. (Pe 2 to 7 are Example compositions, and the others are comparative example compositions). All the pellets were milky white.

  A comparative test (Example 1 to Example 26) for performance evaluation was performed as follows using the pellets (Pe1 to Pe9) in Table 1 above.

(Example 1 to Example 8)
Using a multilayer sheet (T-die) apparatus to which three 40φ extruders are connected, the pellets (Pe1 to Pe9) in Table 1 are used for the core layer, and PET (“9921W” manufactured by Eastman, IV = 0.80) for the inner and outer layers. 270 ° C., shear rate: melt viscosity of 620 P · s at 121 / s), and forming a multilayer sheet of three layers (thickness structure: inner layer / core layer / outer layer = approximately 100 μm / 100 μm / 100 μm) The haze% value was measured. A summary is shown in Table 2 as Examples 1-9.

  The multilayer sheets obtained in Examples 1 to 9 above were heated at 120 ° C. for 10 to 20 seconds, respectively, and a stretched film of about 4 × 4 times in length and width (area ratio 14 to 18 times, thickness) was obtained by simultaneous biaxial stretching. The measurement results shown in Table 3 (Examples 10 to 18) below were obtained.

(Example 19 to Example 22)
Using a pellet Pe6 (PGA / co-PET = 70/30 (% by weight)) in the pellets shown in Table 1, it was melted at 250 ° C. to form a press sheet having a thickness of 100 μm. The haze% was 80% as shown in Table 1. The press sheet was heated at 120 ° C. for 10 to 20 seconds, and a stretched film (single layer) was formed by simultaneous biaxial stretching at different magnifications (Example 19 was not stretched). The measurement results shown in FIG.

(Example 23 to Example 26)
Using the pellet Pe6 (PGA / co-PET = 70/30 (% by weight)) in Table 1 as the core layer and changing the draw ratio, a multilayer stretched film was formed in the same manner as in Example 15, and Table 5 below. The measurement results shown in (Examples 23 to 26) were obtained.

(Example 27)
70% by weight of PGA (manufactured by Kureha Chemical Co., 270 ° C., shear rate: melt viscosity of 820 P · s at 121 / s) with the same heat stabilizer as in 0.05 part by weight of Pe1 per 100 parts by weight, A PGA composition comprising 30% by weight of polyethylene terephthalate (PET) (Eastman “9921W”, IV = 0.80) was melt processed with a 20φ twin-screw extruder (cylinder temperature: 240 to 280 ° C.), and pellets Got.

  Using a multi-layer sheet (T-die) device to which three 40φ extruders are connected, this pellet is placed in the core layer, and PET (9921W manufactured by Eastman, IV = 0.80) is placed in the inner and outer layers. A multilayer sheet (thickness structure: inner layer / core layer / outer layer = approximately 100 μm / 100 μm / 100 μm) was molded. The obtained multilayer sheet was heated at 120 ° C. for 10 to 20 seconds, and stretched 4 × 4 times in length and breadth (area ratio 14 to 18 times, thickness 22 μm) by simultaneous biaxial stretching to obtain a film. The haze% of the multilayer sheet was 70%. Table 6 shows the measurement results for the obtained multilayer stretched film.

(Example 28)
The same mixture as the mixture for Pe6 in Table 1 except that polyamide Ny6 (“Amilan CM1021FS” manufactured by Toray Industries, Inc.) is used instead of co-PET is used as a 20φ small twin screw extruder (cylinder temperature distribution: (C1 / C2 / C3 / D) = 240/250/270/250 ° C.), a black product was generated and foaming was observed. Therefore, the multilayer sheet was not molded.

(Example 29)
A 20φ small twin screw extruder (cylinder temperature distribution: (C1 / C2) was obtained by using the same mixture as that for Pe6 in Table 1 except that low-density polyethylene (“Novatech LD” manufactured by Nippon Polychem Co., Ltd.) was used instead of co-PET. / C3 / D) = 240/250/270/250 ° C.) The two resins were not kneaded. Therefore, instead of extrusion, the sheet was melt-heated and pressed at 250 ° C. and then rapidly cooled to create a sheet, but it was in the form of spots. The film was not molded.

(Example 30)
The same mixture as the mixture for Pe6 in Table 1 except that polylactic acid (“Lacty # 9030” manufactured by Shimadzu Corporation) is used in place of co-PET is converted into a 20φ small twin screw extruder (cylinder temperature distribution: (C1 / C2 / C3 / D) = 240/250/270/250 ° C.) When melt kneading, the viscosity of the molten resin was drastically lowered, and it was not applied to the pellet manufacturing apparatus, and pellets were not obtained. Therefore, the cylinder temperature for kneading was lowered to C1 / C2 / C3 / D = 240/250/270/250 ° C., but the same was true and no pellet was obtained. For this reason, the resin mixture (lumps) was pulverized, melt-heated and pressed at 250 ° C., and then rapidly cooled to create a sheet. However, the sheet was fragile and could not be completely formed. The appearance of the obtained sheet-like material was brown and cloudy.

  The results shown in Tables 1 to 6, especially Table 3, indicate that the physical properties represented by the gas barrier properties of PGA are maintained by blending 1 to 40% by weight of aromatic polyester resin with respect to 99 to 60% by weight of PGA. However, the moisture resistance stability and stretchability are remarkably improved. Also, when comparing the results in Table 2 and Table 3, the gas barrier property is somewhat improved by performing stretching using the stretchability improved by the blending of the aromatic polyester resin, and the transparency is remarkably improved. I understand. Further, by comparing with the results of Examples 28 to 30, the effect of improving the thermal stability and hot melt processing characteristics by the above-described blending of the aromatic polyester resin of the present invention cannot be obtained by blending polyamide, polyethylene and polylactic acid. I understand that.

  As described above, according to the present invention, while maintaining the excellent characteristics typified by the gas barrier property of the PGA resin by blending a relatively small amount of the aromatic polyester resin with the PGA resin, the moisture resistance stability and Provided are PGA compositions and molded articles thereof that have significantly improved hot melt processing properties, as well as improved stretch properties and transparency.

Claims (15)

A polyglycolic acid resin containing a pre-added heat stabilizer in excess of 50% by weight, an aromatic dicarboxylic acid that can be substituted with an aliphatic dicarboxylic acid up to 15 mol%, and a diol and phenol / tetrachloroethane (1 / 1) A polyglycolic acid-based resin composition comprising: an aromatic polyester resin having an intrinsic viscosity of 0.6 to 2.0 dl / g measured at 25 ° C. in a mixed solvent and less than 50% by weight. The resin composition according to claim 1, comprising 99 to 60% by weight of a polyglycolic acid resin and 1 to 40% by weight of an aromatic polyester resin. The resin composition according to claim 1, comprising 90 to 70% by weight of a polyglycolic acid resin and 10 to 30% by weight of an aromatic polyester resin. The heat stabilizer is at least one selected from the group consisting of a heavy metal deactivator, a phosphate ester having a pentaerythritol skeleton structure, a phosphorus compound having at least one hydroxyl group and at least one alkyl ester group, and a metal carbonate. The resin composition according to claim 1, which is a seed compound. The resin composition in any one of Claims 1-4 with which the polyglycolic acid resin by which the heat stabilizer was melt-mixed previously is mix | blended. The resin composition according to claim 1, wherein the aromatic polyester resin is an aromatic polyester copolymer. A molded article comprising the polyglycolic acid resin composition according to any one of claims 1 to 6. The molded product according to claim 7 having a multilayer structure. The molded product according to claim 7 or 8, which is in a film form. The molded article according to claim 8 or 9, wherein the molded article has a multilayer structure, and at least one layer thereof is stretched. 11. A molded article according to claim 10, comprising two or more co-stretched layers. The molded product according to claim 10 or 11, wherein the stretched layer is stretched at least twice in at least one direction. The molded product according to claim 12, wherein the stretched layer is stretched by 4 times or more in area ratio. The molded article according to claim 10 or 11, wherein the stretched layer is stretched about 3 to 4 times in at least one direction. The molded product according to claim 14, wherein the stretched layer is stretched by about 9 to 16 times in area ratio.