JP2003096283A - Translucent polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition which is imparted with excellent shock resistance, particularly, cold shock property though having heat resistance and chemical resistance, and which has good formability and translucency at room temperature, and also to provide a formed article formed using the composition. SOLUTION: The composition is obtained by blending (A) 100 parts by weight of a copolymerized polyethylene terephthalate resin comprising a dicarboxylic acid containing terephthalic acid of from 95 to 60 mol% and isophthalic acid of from 5 to 40 mol% or ester forming derivative thereof, and ethylene glycol, and (B) 80 to 900 pts.wt. of polycarbonate having a viscosity average molecular weight of 17,000 to 28,000.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyester resin composition comprising a copolymerized polyethylene terephthalate resin and a polycarbonate resin, which has translucency at room temperature and is excellent in impact resistance and heat resistance.

[0002]

2. Description of the Related Art Polyethylene terephthalate (hereinafter PE
T) has excellent mechanical properties, electrical properties, chemical resistance, and heat resistance, and is therefore widely used as fibers, films, molding materials and the like. Recently, it has been widely used for packaging sheets such as foods, beverage bottles, etc. by utilizing the transparency, gloss and gas barrier properties of PET films.

However, since the PET resin is a crystalline resin by nature, when molded normally, the molded product obtained by crystallization of the resin becomes cloudy or has transparency at the time of molding. Since it has a problem that crystallization progresses by being exposed to high temperature during use and a whitening phenomenon occurs, special treatment such as stretching of the film is required to suppress this. Has been done. Further, since it is crystalline, it has a low impact resistance, and the obtained molded product has a defect that it is easily cracked. On the other hand, P
It is also known to copolymerize other alcohol components or carboxylic acid components for the purpose of imparting transparency by suppressing the original crystallinity of the ET resin to make it amorphous, but impact resistance However, the melting point and the glass transition point are lowered by making it amorphous, so that heat resistance, which is one of the advantages of PET, is lowered. However, it is not practically preferable.

A resin composition having improved properties such as transparency, dimensional stability and hot-water whitening property of a film has been already developed by melt-mixing the above-mentioned amorphous PET and polycarbonate (hereinafter PC) ( JP-A-53-9704
9 and JP-A-55-23125), no particular remarkable improvement in strength and heat resistance is observed. In addition, due to the expansion of the range of use of resin products, the operating environment temperature range has greatly expanded, and it is required to maintain excellent resin properties in a wide temperature range from low temperature to high temperature. A decrease in toughness of a resin product in a low temperature atmosphere becomes a problem, and a resin having high low temperature impact characteristics is desired. In addition, there are some cases where semi-transparency is required rather than complete transparency as a market need. As a means for making the transparent resin semi-transparent, it is possible to add fine inorganic particles or a third resin component having a low compatibility with the base resin. In order to lower the heat resistance of the composition, or to cause fish eyes at the time of film formation, and to add the third component,
It was difficult to obtain the desired semitransparent resin composition having both low temperature impact characteristics and heat resistance.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a resin composition having heat resistance, chemical resistance, excellent impact resistance, especially low temperature impact characteristics, and translucency. And to provide a molded product molded using the same.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a copolymerized polyethylene terephthalate resin composed of a mixture of terephthalic acid and isophthalic acid in a specific ratio and ethylene glycol is used. Then, the inventors have found that by melting and mixing a polycarbonate resin, a molded article having translucency can be obtained without impairing heat resistance and impact resistance, and the present invention has been completed. That is, the present invention relates to (A) copolymerized polyethylene terephthalate resin 10
0 parts by weight and (B) polycarbonate resin 80 to 90
A resin composition having a translucency at room temperature consisting of 0 parts by weight, wherein (A) is a mixture of (a-1) terephthalic acid of 95 to 60 mol% and isophthalic acid of 5 to 40 mol%.
-2) The present invention relates to a polyester resin composition which is ethylene glycol and has a viscosity average molecular weight of (B) in the range of 17,000 to 28,000. In a further preferred embodiment, the total light transmittance is in the range of 65 to 85%, and the haze is in the range of 15 to 55%, from the polyester resin composition described above. Related to molded articles. Hereinafter, the present invention will be described in detail.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The copolymerized polyethylene terephthalate resin of component (A) used in the present invention comprises a mixture of terephthalic acid (TPA) and isophthalic acid (IPA), and ethylene glycol. .

The mixing ratio of terephthalic acid and isophthalic acid is
Terephthalic acid 95-60 mol%, isophthalic acid 5-40
Mol% is preferred. Furthermore, terephthalic acid 90-65
It is preferable that the content is mol% and isophthalic acid is 10 to 35 mol%. When the amount of terephthalic acid is more than 95 mol% and the amount of isophthalic acid is less than 5 mol%, the crystallinity is high, and the translucency and toughness of the polymer tend to be deteriorated.
On the other hand, when the amount of terephthalic acid is less than 60 mol% and the amount of isophthalic acid is more than 40 mol%, the rigidity of the molecule is significantly reduced, and the heat resistance and mechanical strength tend to be reduced.

The intrinsic viscosity (IV) of the copolymerized polyethylene terephthalate resin is 0.35 dl / g or more, more preferably 0.4 to 2.0 dl / g, and especially 0.45 to 1.5 d.
It is preferably 1 / g. Intrinsic viscosity is 0.35dl /
If it is less than g, the mechanical strength tends to decrease. The intrinsic viscosity is obtained by measuring at 25 ° C. using a mixed solvent of phenol: 1,1,2,2-tetrachloroethane = 1: 1 (weight ratio).

The polycarbonate resin which is the component (B) used in the present invention is produced by reacting one or more bisphenol compounds with carbonic acid ester such as phosgene or diphenyl carbonate. Examples of the bisphenol compound used in the present invention include bis- (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, 1,1-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) butane, 2,2-bis- (4-hydroxyphenyl) pentane, 2,2-bis- (4 -Hydroxyphenyl) -3-
Methyl butane, 2,2-bis- (4-hydroxyphenyl) -4-methylpentane, 1,1-bis- (4-hydroxyphenyl) cyclohexane, bis- (4-hydroxy-3-methylphenyl) methane, 1, 1-bis-
(4-hydroxy-3-methylphenyl) ethane, 2,
2-bis- (4-hydroxy-3-methylphenyl) propane, 2,2-bis- (4-hydroxy-3-iso)
Propylphenyl) propane, 2,2-bis- (4-hydroxy-3-sec-butylphenyl) propane, bis- (4-hydroxyphenyl) phenylmethane, 1,
1-bis- (4-hydroxyphenyl) -1-phenylethane, 1,1-bis- (4-hydroxyphenyl)-
1-phenylpropane, bis- (4-hydroxyphenyl) diphenylmethane, bis- (4-hydroxyphenyl) dibenzylmethane, 4,4'-dihydroxydiphenylether, 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy Examples include diphenyl sulfide. Of these, 2,2-bis- (4-hydroxyphenyl) propane is preferable from the viewpoint of mechanical properties and moldability. The polycarbonate resin is produced by any method, but is preferably produced by the phosgene method or the transesterification method.

The viscosity average molecular weight (M _w ) of the polycarbonate resin is 17,000 to 28,000, and further 1
9000-27,000, especially 20,000-25,000
Is preferred. If the viscosity average molecular weight is less than 17,000, the impact properties are insufficient, and conversely, if the viscosity average molecular weight is more than 28,000, the fluidity tends to decrease and the moldability tends to deteriorate. The viscosity average molecular weight is determined by measuring in methylene chloride at 25 ° C. The blending amount of the polycarbonate resin is 80 to 900 parts based on 100 parts by weight of the (A) copolymerized polyethylene terephthalate resin,
Preferably 90 to 600 parts by weight, more preferably 100
~ 400 parts by weight. If it is less than 80 parts by weight, the effect of improving low-temperature impact resistance is insufficient, and it becomes opaque, and conversely,
If it exceeds 900 parts by weight, the moldability deteriorates, and
It may lose transparency and become transparent.

The translucent polyester-based resin composition of the present invention further comprises known and commonly used antioxidants, ultraviolet absorbers, light stabilizers, lubricants, mold release agents, plasticizers, as long as the characteristics thereof are not impaired. Additives such as pigments, dyes, dispersants, and compatibilizers can be used alone or in combination of two or more. The method for producing the translucent polyester resin composition of the present invention is not particularly limited. For example, it can be produced by a method in which each component is dried and then melt-kneaded in a melt-kneader such as a single-screw or twin-screw extruder. Molding method of the thermoplastic resin composition produced in the present invention,
The molding method is not particularly limited, and molding methods generally used for thermoplastic resins, for example, molding methods such as injection molding, hollow molding, extrusion molding, sheet molding, roll molding, press molding, laminating molding and spinning. Is applied.

[0013]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited thereto.

(Example 1) (A-1) The mixing ratio of terephthalic acid and isophthalic acid was 8
0:20 (mol: mol), intrinsic viscosity = 0.75dl / g
Copolymerized polyethylene terephthalate resin (PET-
1) 100 parts by weight, (B-1) viscosity average molecular weight = 22
000 polycarbonate resin (Taflon A2200:
100 parts by weight of Idemitsu Chemical Co., Ltd., and a phenolic antioxidant (trade name ADEKA STAB AO-) as an antioxidant.
60: 0.1 part by weight of Asahi Denka Kogyo Co., Ltd., 0.1 part by weight of phosphite type antioxidant (trade name ADEKA STAB HP-10: Asahi Denka Kogyo KK) were added and mixed, A resin composition was obtained by using a TEX44 vented twin-screw extruder manufactured by Japan Steel Works Ltd., setting the barrel temperature to 280 ° C., charging from a hopper, and melt-extruding.

(Evaluation Method) After drying the obtained resin composition and comparative resin composition at 140 ° C. for 4 hours, 80 t
120 mm x 120 m, injection molding is performed using an injection molding machine at a cylinder temperature of 280 ° C and a mold temperature of 40 ° C.
m × 3 mm thick flat plate, using a 75t injection molding machine, at cylinder temperature = 280 ° C., mold temperature = 40 ° C.,
A 127 mm × 12.7 mm × 6.4 mm thick bar test piece was obtained and evaluated as follows.

<Total Light Transmittance and Haze> As an evaluation of translucency, a 120 mm × 120 mm × 3 mm thick flat plate was used, and a light transmittance measuring device NDH-1001 was used.
Total light transmittance and haze were measured using DP (manufactured by Nippon Denshoku Industries Co., Ltd.).

<Surface Impact Strength Properties> For evaluation of impact resistance, a 120 mm × 120 mm × 3 mm thick flat plate was used and a high-speed impact tester (manufactured by Shimadzu Corporation) was used at 23 ° C. and −30 ° C. The breaking strength of was measured.

<Deflection temperature under load> As an evaluation of heat resistance,
Deflection temperature under load (HDT) at 0.45 MPa load according to ASTM D-648 using a 6.4 mm thick bar.
Was evaluated.

<Koka type flow> As an evaluation of molding processability, after drying the pellets at 140 ° C. for 4 hours or more, 28
Fill in the furnace of the Koka type flow tester heated to 0 ℃,
After preheating for 5 minutes, the fluidity per unit time under a load of 9.8 MPa was evaluated.

(Examples 2 to 5) (A-2) The mixing ratio of terephthalic acid and isophthalic acid was 8
5:15 (mol: mol), intrinsic viscosity = 0.73 dl / g
Copolymerized polyethylene terephthalate resin (PET-
2) (A-3) The mixing ratio of terephthalic acid and isophthalic acid is 7
0:30 (mol: mol), intrinsic viscosity = 0.68dl / g
Copolymerized polyethylene terephthalate resin (PET-
3) (B-2) A resin was prepared in the same manner as in Example 1 except that a polycarbonate resin having a viscosity average molecular weight of 25000 (Taflon A2500: manufactured by Idemitsu Chemical Co., Ltd.) was used and mixed in the proportions shown in Table 1. The composition was obtained and the same evaluation was performed.

Comparative Example 1 (A-4) The mixing ratio of terephthalic acid and isophthalic acid was 10
100 parts by weight of polyethylene terephthalate (PET-4) having 0: 0 (mol: mol) and an intrinsic viscosity of 0.59 dl / g, (B-1) a polycarbonate resin having a viscosity average molecular weight of 22000 (Taflon A2200: Idemitsu Chemical ( stock)
250 parts by weight, 0.1 part by weight of a phenolic antioxidant (trade name ADEKA STAB AO-60: Asahi Denka Kogyo KK) as an antioxidant, and a phosphite antioxidant (trade name ADEKA STAB HP- 10: Asahi Denka Co., Ltd.
0.1 part by weight was added and mixed, and then, with a twin-screw extruder with a TEX44 vent manufactured by Japan Steel Works, Ltd., the barrel temperature was set to 280 ° C., and the mixture was charged from a hopper and melt-extruded. After obtaining the resin composition, evaluation was performed by the same method as in Example 1.

Comparative Examples 2 to 6 (A-1) The mixing ratio of terephthalic acid and isophthalic acid was 8
0:20 (mol: mol), intrinsic viscosity = 0.75dl / g
Copolymerized polyethylene terephthalate resin (PET-
1) (A-2) The mixing ratio of terephthalic acid and isophthalic acid is 8
5:15 (mol: mol), intrinsic viscosity = 0.73 dl / g
Copolymerized polyethylene terephthalate resin (PET-
2) (A-5) The mixing ratio of terephthalic acid and isophthalic acid is 5
0:50 (mol: mol), intrinsic viscosity = 0.72 dl / g
Copolymerized polyethylene terephthalate resin (PET-
5) (B-3) Polycarbonate resin having a viscosity average molecular weight of 15000 (Taflon A1500: manufactured by Idemitsu Chemical Co., Ltd.) (B-4) Polycarbonate resin having a viscosity average molecular weight of 30000 (Novarex 7030A: manufactured by Mitsubishi Engineering Co., Ltd.) ) Was used, and a resin composition was obtained in the same manner as in Example 1 except that the mixture was mixed in the ratio shown in Table 2, and the same evaluation was performed. The results of Examples 1 to 5 are shown in Table 1, and the results of Comparative Examples 1 to 6 are shown in Table 2.

[0023]

[Table 1]

[0024]

[Table 2]

In order to obtain a good molded product using the composition of the present invention, the required characteristic values are semitransparency in terms of total light transmittance of 65 to 85% and haze. Is 1
It is preferably in the range of 5 to 55%, and from the viewpoint of impact resistance, high-speed impact strength is 3500 N or more at 23 ° C., -3
At 0 ° C., 400 N or more is preferable, from the viewpoint of moldability, the Koka type flow value is preferably 10 cm ³ / sec or more, and from the viewpoint of heat resistance, the deflection temperature under load is preferably 100 ° C. or more.

As is clear from the results of the comparative example in Table 2,
In Comparative Example 1, the amount of TPA in the copolymerization ratio of TPA and IPA was larger than the claimed range, so the total light transmittance was low, the haze was high, and the high-speed impact value was low. Then, since the amount of TPA in the copolymerization ratio of TPA and IPA was lower than the claimed range, the deflection temperature under load was low, and in Comparative Example 3, in the blending ratio of copolymerized PET and PC, PC
Since the ratio of is less than the claimed range, the total light transmittance is low, and the haze is high, the high-speed impact value and the deflection temperature under load are also low. In Comparative Example 4, the mixing ratio of the copolymerized PET and PC is Since the ratio of PC is higher than the claimed range, the total light transmittance is high, the haze is low, and the high flow rate value is also low. In Comparative Example 5, the molecular weight of PC is lower than the claimed range. Therefore, the high-speed impact value becomes low, and Comparative Example 6
In, since the molecular weight of PC was higher than the claimed range, the flow value of Koka type equation was low, and in Comparative Example 7, since the copolymerized PET was not used, the total light transmittance was high, and the haze was low, which was high. The chemical formula flow value also becomes low, which is not preferable in the present invention. On the other hand, as is clear from the results described in the examples, all of the compositions of the present invention, while satisfying the target total light transmittance, haze, excellent impact resistance, heat resistance, molding process Have sex.

[0027]

INDUSTRIAL APPLICABILITY The resin composition having translucency of the present invention is excellent in heat resistance, chemical resistance, translucency, impact characteristics (especially low temperature surface impact characteristics), and moldability, and is industrially used. Is also useful.

Claims (2)

[Claims] 1. A resin composition comprising 100 parts by weight of (A) a copolymerized polyethylene terephthalate resin and 80 to 900 parts by weight of a (B) polycarbonate resin,
(A) consists of a mixture of (a-1) terephthalic acid 95-60 mol% and isophthalic acid 5-40 mol% and (a-2) ethylene glycol, and (B) has a viscosity average molecular weight of 17,000-28,000. The polyester resin composition having translucency at room temperature, which is in the range of. 2. A molded article comprising the polyester resin composition according to claim 1, which has a total light transmittance of 65 to 85% and a haze of 15 to 55%.