Polyester resin composition and molding

Abstract

The present invention aims to provide a polyester resin composition capable of producing a molded article having excellent stretchability. The present invention also aims to provide a molded article including the polyester resin composition. The present invention relates to a polyester resin composition including: a polyester resin; and a polyrotaxane that has a cyclic molecule, a linear molecule threading through a cavity of the cyclic molecule in a skewered manner, and capping groups capping both ends of the linear molecule.

Claims

1. A polyester resin composition comprising: a polyester resin; and a polyrotaxane that has a cyclic molecule, a linear molecule threading through a cavity of the cyclic molecule in a skewered manner, and capping groups capping both ends of the linear molecule, wherein a polycaprolactone chain is introduced to the cyclic molecule, the polycaprolactone chain has a carboxyl group as a substituent at its terminal, and the polyrotaxane contains polyethylene glycol as the linear molecule and a molecule derived from -cyclodextrin as the cyclic molecule.

2. The polyester resin composition according to claim 1, wherein the polyester resin contains a polylactic acid resin and/or a polyglycolic acid resin.

3. A molded article comprising the polyester resin composition according to claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a transmission electron microscope photo of a resin composition obtained in Example 4.

DESCRIPTION OF EMBODIMENTS

(2) The present invention is more specifically described in the following with reference to, but not limited to, examples. The polyrotaxane used in preparation examples was prepared with reference to the method disclosed in JP 2011-241401 A.

Preparation Example 1

(3) (Preparation of Carboxylated Polyrotaxane (Colorless Rubber-Like Material))

(4) An amount of 100 g of a 35% by mass xylene solution of polyrotaxane (inclusion rate of cyclic molecule: 25%, mass average molecular weight: 470,000, hydroxy value: 74 mgKOH/g; hereafter, also referred to as PR) having: polyethylene glycol (mass average molecular weight: 35,000) as a linear molecule; -cyclodextrin (substitution degree of hydroxypropyl group: 51%) in which a hydroxypropyl group is introduced and then -caprolactone was graft-polymerized as a cyclic molecule; and adamantane amine groups as capping groups was prepared. The solution was blended with 9.2 g of a mixture of 4-methyl hexahydrophthalic anhydride and hexahydrophthalic anhydride (RIKACID MH-700, New Japan Chemical Co., Ltd.), 14.0 g of triethylamine, and 0.34 g of 4-dimethylaminopyridine. The mixture was stirred at 80 C. for three hours. The resulting mixed liquid was cooled to room temperature, blended with 32.3 g of p-toluenesulfonic acid monohydrate, and stirred at room temperature for 30 minutes. The resulting white slurry was blended with a large amount of methanol for precipitation of polymers. The supernatant was removed, and the polymers were washed with methanol three times to give a white precipitate. The white precipitate was dried at 120 C. for three hours, thereby obtaining 40 g of a carboxylated polyrotaxane in the form of a colorless rubber-like material. The acid value of the carboxylated polyrotaxane in the form of a colorless rubber-like material was determined by a method in conformity with JIS K 0070. The result showed that the introduction rate (modification rate) of carboxyl groups was 89.2%.

Preparation Example 2

(5) (Preparation of Carboxylated Polyrotaxane (White Rubber-Like Material))

(6) An amount of 100 g of the 35% by mass xylene solution of PR described in Preparation Example 1 was blended with 9.2 g of a mixture of 4-methyl hexahydrophthalic anhydride and hexahydrophthalic anhydride (RIKACID MH-700, New Japan Chemical Co., Ltd.), and stirred at 80 C. for six hours. The obtained mixed liquid was cooled to room temperature, blended with a large amount of methanol for precipitation of polymers. The supernatant was removed, and the polymers were washed with methanol three times to give a white precipitate. The white precipitate was dried at 80 C. for three hours, thereby obtaining 37 g of a carboxylated polyrotaxane in the form of a white rubber-like material. The acid value of the carboxylated polyrotaxane in the form of a white rubber-like material was determined by a method in conformity with JIS K 0070. The result showed that the introduction rate (modification rate) of carboxyl groups was 70.6%.

Examples 1 to 5

(7) The polyester resin used was a crystalline polylactic acid (IngeoPolymer 2003D, Natureworks LLC., poly(L-lactic acid), mass average molecular weight: 200,000). The polyrotaxane used was the above PR. They were dissolved in chloroform at a ratio shown in Table 1, and stirred for one hour. The chloroform was removed, thereby preparing a resin composition.

(8) FIG. 1 is a transmission electron microscope photo of a resin composition obtained in Example 4.

Comparative Example 1

(9) A resin composition was prepared in the same manner as in Example 1, except that no polyrotaxane was used.

Comparative Example 2

(10) A resin composition was prepared in the same manner as in Example 4, except that the polyrotaxane was changed to poly(-caprolactone) (Placcel 302, Daicel Corporation).

Comparative Example 3

(11) A resin composition was prepared in the same manner as in Example 1, except that the polyrotaxane was changed to poly(-caprolactone) (Placcel 302, Daicel Corporation).

Comparative Example 4

(12) A resin composition was prepared in the same manner as in Example 4, except that the polyrotaxane was changed to polyethylene glycol (Wako Pure Chemical Industries, Ltd.).

Comparative Example 5

(13) A resin composition was prepared in the same manner as in Example 1, except that the polyrotaxane was changed to glycerol diacetomonolaurate (Rikemal PL-012, Riken Vitamin Co., Ltd.) as a low-molecular-weight plasticizer.

Examples 6 and 7

(14) Crystalline polylactic acid (IngeoPolymer 2003D, Natureworks LLC., poly(L-lactic acid) acid, mass average molecular weight: 200,000) as the polyester resin and the carboxylated polyrotaxane in the form of a colorless rubber-like material synthesized in Preparation Example 1 as the polyrotaxane were charged into a kneading and extrusion tester (Laboplastomill 4C150, Toyo Seiki Seisakusho, Ltd.) at a ratio shown in Table 1, and melt-kneaded at 190 C. and at a rotation speed of 50 rpm for 10 minutes to give a resin composition.

Example 8

(15) A resin composition was prepared in the same manner as in Example 6, except that the carboxylated polyrotaxane in the form of colorless rubber-like material prepared in Preparation Example 1 was changed to the carboxylated polyrotaxane in the form of a white rubber-like material prepared in Preparation Example 2.

Example 9

(16) A resin composition was prepared in the same manner as in Example 6, except that the polyester resin was changed from the crystalline polylactic acid to an amorphous polylactic acid (IngeoPolymer 4060D, Natureworks LLC., poly(DL-lactic acid), mass average molecular weight: 100,000).

Comparative Example 6

(17) A resin composition was prepared in the same manner as in Example 6, except that no polyrotaxane was used.

Comparative Example 7

(18) A resin composition was prepared in the same manner as in Example 9, except that no polyrotaxane was used.

Examples 10 and 11

(19) A semi-crystalline polyglycolic acid (Kuredux 100R60, Kureha Corporation, mass average molecular weight: 170,000) as the polyester resin and the carboxylated polyrotaxane in the form of a colorless rubber-like material synthesized in Preparation Example 1 as the polyrotaxane were charged into a kneading and extruding tester (Laboplastomill 4C150, Toyo Seiki Seisakusho, Ltd.) at a ratio shown in Table 1, and melt-kneaded at 230 C. and at a rotation speed of 50 rpm for 10 minutes to give a resin composition.

Comparative Example 8

(20) A resin composition was prepared in the same manner as in Example 10, except that no polyrotaxane was used.

Comparative Example 9

(21) Polycarbonate (Panlite L1225-Y, Teijin Chemicals Ltd., mass average molecular weight: 22,000) and the carboxylated polyrotaxane in the form of a colorless rubber-like material synthesized in Preparation Example 1 as the polyrotaxane were charged into a kneading and extruding tester (Laboplastomill 4C150, Toyo Seiki Seisakusho, Ltd.) at a ratio shown in Table 2, and melt-kneaded at 260 C. and at a rotation speed of 50 rpm for 10 minutes to give a resin composition.

Comparative Example 10

(22) A resin composition was prepared in the same manner as in Comparative Example 9, except that no polyrotaxane was used.

(23) <Evaluation>

(24) The resin compositions obtained in the examples and comparative examples were evaluated for the following parameters. Tables 1 and 2 show the results.

(25) (Yield Stress, Breaking Stress, Breaking Elongation, and Tensile Modulus of Elasticity)

(26) The resin composition obtained in each of the examples and comparative examples was sandwiched between metal plates, pressed at 180 C. (240 C. in the case of the resin compositions of Comparative Examples 9 and 10) and 10 MPa for two minutes, and cooled in a cooling press machine at 20 C. for two minutes, thereby preparing a molded article in a sheet shape with a size of 100 mm in length100 mm in width0.6 mm in thickness. A test sample for a tensile test was cut out from the obtained molded article in conformity with JIS K 7162-5B.

(27) The obtained sample was subjected to a tensile test at a measurement temperature of 25 C. and a tension rate of 20 ram/min using a universal tester (AGS-J, Shimadzu Corporation) for determining the yield stress, breaking stress, and breaking elongation. The tensile test was also performed at a measurement temperature of 25 C. and a tension rate of 1 ram/min for determining the tensile modulus of elasticity.

(28) (Total Light Transmittance)

(29) The resin composition of each of the examples and comparative examples in which a polylactic acid was used was sandwiched between metal plates, pressed at 180 C. and 10 MPa for two minutes, and cooled in a cold press machine at 20 C. for two minutes, thereby preparing a molded article in the sheet shape with a size of 100 mm in length100 mm in width0.2 mm in thickness. The total light transmittance of the obtained molded article was determined using a haze meter (NDH 300A, Nippon Denshoku Industries Co., Ltd.).

(30) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 Composition Polyester resin Crystalline polylactic acid 90 95 97 99 99.5 99 (parts by Amorphous polylactic acid mass) Semi-crystalline polyglycolic acid Poly(-caprolactone) Polyrotaxane PR 10 5 3 1 0.5 Carboxylated polyrotaxane 1 (colorless rubber-like material) Carboxylated polyrotaxane (white rubber-like material) Polyethylene glycol Low-molecular-weight plasticizer Polycarbonate Production method Solution Solution Solution Solution Solution Melt mixing mixing mixing mixing mixing kneading Evaluation Yield stress (MPa) 40 56 53 59 63 66 Breaking stress (MPa) 36 47 28 27 40 42 Breaking elongation (%) 332 368 202 233 266 279 Tensile modulus of elasticity (GPa) 2.3 1.9 2.2 2.4 2.9 2.7 Total light transmittance (%) 88 90 91 94 95 94 Example 7 8 9 10 11 Composition Polyester resin Crystalline polylactic acid 99.5 99 (parts by Amorphous polylactic acid 99 mass) Semi-crystalline polyglycolic acid 97 99 Poly(-caprolactone) Polyrotaxane PR Carboxylated polyrotaxane 0.5 1 3 1 (colorless rubber-like material) Carboxylated polyrotaxane 1 (white rubber-like material) Polyethylene glycol Low-molecular-weight plasticizer Polycarbonate Production method Melt Melt Melt Melt Melt kneading kneading kneading kneading kneading Evaluation Yield stress (MPa) 63 68 56 89 91 Breaking stress (MPa) 43 43 44 83 70 Breaking elongation (%) 260 272 319 59 20 Tensile modulus of elasticity (GPa) 3.2 3.0 2.9 5.2 5.2 Total light transmittance (%) 94 94 94

(31) TABLE-US-00002 TABLE 2 Comparative Example 1 2 3 4 5 6 Composition Polyester resin Crystalline polylactic acid 100 99 90 99 90 100 (parts by Amorphous polylactic acid mass) Semi-crystalline polyglycolic acid Poly(-caprolactone) 1 10 Polyrotaxane PR Carboxylated polyrotaxane (colorless rubber-like material) Carboxylated polyrotaxane (white rubber-like material) Polyethylene glycol 1 Low-molecular-weight plasticizer 10 Polycarbonate Production method Solution Solution Solution Solution Solution Melt mixing mixing mixing mixing mixing kneading Evaluation Yield stress (MPa) 66 65 30 57 28 69 Breaking stress (MPa) 63 52 32 49 38 65 Breaking elongation (%) 3 5 431 10 350 6 Tensile modulus of elasticity (GPa) 3.7 2.9 2.0 2.3 1.0 3.8 Total light transmittance (%) 95 95 85 95 95 95 Comparative Example 7 8 9 10 Composition Polyester resin Crystalline polylactic acid (parts by Amorphous polylactic acid 100 mass) Semi-crystalline polyglycolic acid 100 Poly(-caprolactone) Polyrotaxane PR Carboxylated polyrotaxane 3 (colorless rubber-like material) Carboxylated polyrotaxane (white rubber-like material) Polyethylene glycol Low-molecular-weight plasticizer Polycarbonate 97 100 Production method Melt Melt Melt Melt kneading kneading kneading kneading Evaluation Yield stress (MPa) 63 97 63 65 Breaking stress (MPa) 55 97 62 65 Breaking elongation (%) 9 7 122 128 Tensile modulus of elasticity (GPa) 2.6 6.5 1.6 1.8 Total light transmittance (%) 96

(32) Tables 1 and 2 show that the yield stress of a molded article prepared using each of the resin compositions of the examples in which polyrotaxane was used was equivalent to that of the resin compositions of Comparative Examples 1 and 6 to 8 in which no polyrotaxane was used, whereas the breaking elongation of the resin compositions in the case of the examples was much higher than that of the resin compositions of Comparative Examples 1 and 6 to 8. The resin compositions of Comparative Examples 2 and 4 in which polycaprolactone or polyethylene glycol that was a partial structure of the polyrotaxane was used instead of polyrotaxane failed to achieve such an effect. The resin compositions of Comparative Examples 3 and 5 prepared using a large amount of polycaprolactone or a low-molecular-weight plasticizer achieved significant improvement of the breaking elongation as in the case of using polyrotaxane. In these cases, however, the yield stress, tensile modulus of elasticity, and total light transmittance were markedly lowered.

(33) Examples 6 and 9 in Table 1 show that, in both cases of using a crystalline polyester resin and an amorphous polyester resin, the effect of significantly improving the breaking elongation without markedly lowering the yield stress was achieved.

(34) Comparison between Examples 10 and 11 and Comparative Example 8 shows that, even in the case of using polyglycolic acid as a polyester resin, the use of polyrotaxane in admixture with the polyglycolic acid significantly improved the breaking elongation without markedly lowering the yield stress.

(35) Comparative Examples 9 and 10 in Table 2 show that a polycarbonate resin used in admixture with polyrotaxane failed to achieve the above effects.

(36) FIG. 1 shows that polyrotaxane forms very fine domains with a size of at most several tens of nanometers in the polyester resin composition of the present invention. This shows that polyrotaxane has excellent compatibility with a polyester resin.

INDUSTRIAL APPLICABILITY

(37) The present invention can provide a polyester resin composition capable of providing a molded article having excellent stretchability. The present invention can also provide a molded article including the polyester resin composition.