JPH07247411A - Polyester resin composition - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a polyester resin composition having excellent mechanical properties and significantly improved creep properties, heat resistance and melt stability. [Structure] 1 part by weight to 45 parts by weight of a polyolefin which is a copolymer of an ethylene component and an olefin having a cyclic structure and which is amorphous and has a glass transition temperature of 100 ° C. or higher is added to 100 parts by weight of a polyester resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to melt stability, heat resistance,
The present invention relates to a polyester resin composition having excellent weather resistance, creep properties, molding shrinkage, hydrolysis properties, mechanical properties, and the like, and a low specific gravity, particularly a polyester resin composition containing polyethylene terephthalate and polybutylene terephthalate as main components.

[0002]

BACKGROUND OF THE INVENTION A polyester resin composition comprising a copolymer of a polyester resin containing polyethylene terephthalate or polybutylene terephthalate as a main component and an ethylene component and an olefin having a cyclic structure has heat resistance and chemical resistance, and has a water absorption property. It is known as a resin with low properties and molding shrinkage.

Further, the conventional polyester resin composition composed of a polyester resin and a cyclic polyolefin has low inherent melt stability of the polyester resin and solves the problem that it is easily decomposed when retained in a molten state for molding. .

[0004]

However, although the conventional polyolefin-modified polyester resin composition has improved melt stability, the mechanical properties which are inherent properties of polyester may be significantly deteriorated.

In the present specification, high melt stability means that
As will be described later in detail, it means that the melt viscosity when the residence time is long in the capillograph is sufficiently higher than the melt viscosity when the residence time is short. When the melt stability is low, so-called burrs are liable to occur during molding of the resin composition, which not only impairs the appearance of the molded product but also causes variations in the size and weight of the molded product.

Since a large molding machine must be used in order to make a large-sized molded article such as an automobile outer plate part such as a wheel cover or a fender, the residence time is inevitably long and a stable molded article is manufactured. Therefore, excellent melt stability is required. Further, these molded products are required to have excellent melt stability at the same time. In addition, these moldings must simultaneously have excellent mechanical properties. For example,
In the case of ordinary glass-reinforced resin molded products, the tensile elongation is often required to be at least 1.5% or more.

The present invention is a polyester containing polyethylene terephthalate or polybutylene terephthalate as a main component, which has excellent mechanical properties and is capable of low temperature mold molding with significantly improved creep properties, heat resistance and melt stability. An object is to provide a resin composition.

[0008]

Means for Solving the Problems The present invention has conducted extensive studies to solve the above problems, and as a result, by adding a certain amount of an amorphous cyclic polyolefin to a polyester resin, the original properties of the polyester can be improved. Without compromising
The present invention has been completed by finding that the melt stability is remarkably improved. That is, the present invention is based on 100 parts by weight of a polyester resin, 1 part by weight of a polyolefin which is a copolymer of an ethylene component and an olefin having a cyclic structure, is amorphous, and has a glass transition temperature of 100 ° C. or higher.
It is characterized by being mixed with 45 parts by weight.

The polyethylene terephthalate used in the present invention is preferably one having an intrinsic viscosity of at least about 0.4 at 30 ° C. in methylene chloride and trifluoroacetic acid in a volume ratio of 3: 1 and up to about 1.2. It is preferable to use one having an intrinsic viscosity. The polybutylene terephthalate used in the present invention has a content of at least 0.4 to 1.2 when measured in a 0.1% m-cresol solution at 30 ° C.
Is preferred.

The blending amount of the amorphous cyclic polyolefin is determined in consideration of the physical properties of the molded product to be obtained, but is preferably 1 to 45 parts by weight and more preferably 3 to 30 parts by weight per 100 parts by weight of the polyester resin. This range is a range in which the tensile elongation of the molded product is 1.5% or more when, for example, 30 parts by weight of an inorganic reinforcing substance such as glass fiber is mixed with 100 parts by weight of the mixture of polyester resin and polyolefin.

Further, in the case of blending an inorganic reinforcing substance or a flame retardant, the blending amount of the amorphous cyclic polyolefin is about 1 to 20% by weight based on the entire composition,
It is preferably about 2 to 15% by weight. If it is 1% by weight or less, it is difficult to obtain sufficient melt stability due to the amorphous cyclic polyolefin, and if it is 15% by weight or more, the heat resistance and mechanical properties of the obtained molded product tend to be deteriorated. 30% by weight
When added in the above amount, resin delamination easily occurs in the molded product.

When no inorganic reinforcing substance or flame retardant is added to automobile exterior parts, the amount of the amorphous cyclic polyolefin may be up to about 150 parts by weight based on 100 parts by weight of the polyester resin. it can.

Glass fiber contained in the composition of the present invention,
The inorganic reinforcing substance or flame retardant such as mica and whiskers is a mixture of polyester resin and polyolefin 10
5 to 150 parts by weight can be added to 0 parts by weight. A molded article obtained from a composition containing these inorganic reinforcing substances and the like has excellent melt stability and moisture absorption resistance, as well as excellent heat resistance, synthesis, and mechanical strength.

Further, the polyester resin composition of the present invention, particularly the polyethylene terephthalate composition, preferably contains a nucleating agent in order to improve the low temperature moldability. As the nucleating agent, a sodium compound and / or a potassium compound can be used. Part or all of these sodium compounds and potassium compounds may be replaced with talc. Various nucleating agents can also be used. Further, a part or all of the polyester, which is the main component of the present invention, may be replaced with polyethylene terephthalate having a terminal sodium or potassium. This end-treated polyethylene terephthalate is
It is described in U.S. Pat. No. 4,425,470 and can be produced by the method described therein. If this terminal sodium- or potassium-modified polyethylene terephthalate is used, it may not be necessary to additionally attach a nucleating agent.

The composition of the present invention exhibits a good melt viscosity without the addition of a plasticizer, but the melt viscosity may be adjusted by adding a plasticizer. In addition, various additives such as an antioxidant and a stabilizer can be added to the composition of the present invention.

In order to produce the polyester resin composition of the present invention, a method of melt kneading is used, and a kneading apparatus such as a Banbury mixer, an extruder and various kneaders which are generally used can be used. Regarding the kneading order when producing the polyester resin composition of the present invention, the respective components may be kneaded at once, or the polyolefin may be supplied from a side feeder.

Since the polyester resin composition of the present invention has a high melt stability, it is possible to obtain an excellent molded product which is less likely to cause flash during molding, has a good appearance, and has less variation in size and weight. Further, since the polyester resin composition of the present invention has good moisture absorption resistance, the polyethylene terephthalate pellets can be molded immediately after opening the paper bag without drying, and the moldability is good, and the strength and the appearance are excellent. Give a molded article.

[0018]

The present invention will be described in more detail with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

The compositions of Examples 1 to 5 and Comparative Example containing the components shown in the following table were prepared and the measurement results of the physical properties shown in the table were obtained.

[0020]

[Table 1]

The following ingredients were used in these examples and comparisons. Polyethylene terephthalate (PE
T) is manufactured by DuPont and has an intrinsic viscosity of about 0.67.
Is 0.58.

The amorphous cyclic polyolefin is a copolymer of ethylene and an olefin having a cyclic structure and is amorphous, and has a glass transition temperature of 100 ° C. or higher.
Such an amorphous cyclic polyolefin C can be produced, for example, by using a Ziegler-Natta catalyst, and as a commercially available product, a cyclic olefin copolymer “Apel” (registered trademark: Mitsui Petrochemical Industry Co., Ltd.) and the like can be mentioned. . As the sodium salt, Surlyn 8920 manufactured by DuPont was used. In addition to this, a plasticizer and an oxidizing agent were also added to the core composition sample.

The resin, nucleating agent, and other additives in the parts by weight shown in the above table were premixed for 20 minutes by a tumbler, and then the twin-screw extruder TEM35B manufactured by Toshiba Machine Co., Ltd. was used.
A resin composition was obtained by melt-kneading at a temperature of 0 ° C. Shear stress 121 at 280 ° C. and 250 ° C. for polyethylene terephthalate and polybutylene terephthalate, respectively, using a Capillograph manufactured by Toyo Seiki Co., Ltd. for these resin compositions.
The melt viscosity at 6 (sec ^-1 ) was measured. Here, the dry melt viscosity refers to the melt viscosity when measured using a pellet having a water content of 0.02% or less with a residence time of 3 minutes. The melt viscosity at the time of residence is the melt viscosity when measured using a pellet having a water content of 0.02% or less at a residence time of 30 minutes.

The retention rate of melt viscosity at the time of retention is determined by the following formula.

Melt viscosity retention during retention (%) − (A / B) × 100 A = melt viscosity during residence, B = standard melt viscosity Regarding the physical property test, after drying this resin composition at 135 ° C. for 3 hours. , A polyethylene terephthalate and polybutylene terephthalate composition was prepared using a molding machine at 290 ° C. and 260 ° C. and a mold temperature of 110 ° C. and 80 ° C. to prepare standard physical property test pieces, and the physical properties of the resin composition when dried Was measured. The test method is ASTM-
638, and the bending test was performed according to ASTM-790. The Izod impact test was based on D-256.

As is clear from the measurement results shown in the above table, the polyester resin composition of the present invention is a resin having excellent mechanical properties and heat resistance of the polyester resin and excellent melt stability. It is a composition.

[0027]

EFFECTS OF THE INVENTION The polyester resin composition of the present invention is a mixture of polyester resin with a predetermined amount of amorphous cyclic polyolefin. Therefore, the polyester resin composition has excellent mechanical properties and heat resistance and melt stability. Is an improved one.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area C08L 23:08)

Claims (4)

[Claims] 1. 1 part by weight to 45 parts by weight of a polyolefin, which is a copolymer of an ethylene component and an olefin having a cyclic structure, is amorphous and has a glass transition temperature of 100 ° C. or higher, is added to 100 parts by weight of a polyester resin. A polyester resin composition comprising: 2. The polyester resin composition according to claim 1, wherein the ethylene copolymer having glycidyl methacrylate or glycidyl acrylate is added in an amount of 0.5 to 30 parts by weight per 100 parts by weight of the mixture of the polyester resin and the polyolefin. A polyester resin composition, characterized by containing 1 part by weight. 3. The polyester resin composition according to claim 1, further comprising 5 to 150 parts by weight of an inorganic reinforcing substance or flame retardant with respect to 100 parts by weight of the mixture of the polyester resin and the polyolefin. A characteristic polyester resin composition. 4. An automobile outer panel component molded by using the polyester resin composition according to any one of claims 1 to 3.