JPS60228554A - Polyethylene terephthalate resin composition - Google Patents

Abstract

PURPOSE:The titled resin composition producing, with good moldability, a molded article having excellent mechanical strength and dimensional stability, made by compounding a polyethylene terephthalate resin, glass fibers, a nucleating agent, and specified ether ester compound. CONSTITUTION:30-90wt% polyethylene terephthalate resin (with the intrinsic viscosity of about 0.4-1.4), 5-60wt% glass fibers (chopped strands of a length of about 0.4-6mm.), 0.03-30wt% nucleating agent (e.g. sodium stearate), and 0.1- 10wt% ether ester compound of formula I [where R1 is hydrocarbon group of at least 1C; R2 is a hydrocarbon group of 2-6C; X is -CH2-, -SO2- or of formula IIor III (where R3 and R4 are each a hydrocarbon group of at least 1C); n is 1-5] (e.g. a compound of formula IV), are compounded (the total composition being 100wt%).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polyethylene terephthalate resin composition, and more particularly to a highly crystalline glass fiber reinforced polyethylene terephthalate resin composition.

[Technical background of the invention and its problems]

It is known that glass fiber reinforced polyethylene terephthalate resins have excellent mechanical properties, chemical resistance, and the like. However, since the properties of crystalline polymers such as polyethylene terephthalate resin strongly depend on the degree of crystallinity, when such reinforced resins are molded at a low mold temperature of 100°C or less, the crystallization of the resin does not proceed sufficiently. As a result, the moldability of the resulting resin is poor, the heat deformation temperature is around 100° C., and the heat resistance is also poor. Therefore, as a method for promoting crystallization, there is a method of post-heating a molded product that is still in a partially crystallized state to promote crystallization.
A method of immersing the molded article in a liquid that promotes crystallization has also been proposed. However, all of these methods require post-processing after molding, and have the disadvantage that the molded product is easily deformed during such post-processing.

Conventionally, instead of using the above method, the mold temperature was
The only option available was to maintain the temperature at a high temperature of 20 to 150°C to promote crystallization during the molding process, but this method had poor economic efficiency and work stability due to the use of molds at high temperatures. There were some difficulties in terms of aspects.

Therefore, in order to improve the above-mentioned drawbacks, a method has been proposed in which a crystal nucleating agent such as a metal salt of an organic carboxylic acid or an inorganic compound is added to lower the mold temperature in °C. However, the above-mentioned drawbacks have not yet been fully resolved even at temperatures below 100°C, and when molding is carried out at a mold temperature of 100°C or lower, crystallization progresses (because of this, the mold releasability deteriorates. , 1 In order to improve the IlI type property, it is necessary to cool down slowly, so we reduced the cooling time.Also, since the crystallinity of the obtained molded product is low, if the wall thickness of the molded product is made thinner. The heat resistance was insufficient, and furthermore, when this molded product was used in a high temperature atmosphere, crystallization progressed, causing post-shrinkage and reducing dimensional stability.

[Purpose of the invention]

The invention is to overcome the above drawbacks and to create a highly crystalline product that can produce molded products with a high heat deformation temperature and excellent moldability, mold releasability, and dimensional stability without reducing mechanical strength. The object of the present invention is to provide a polyethylene terephthalate resin composition.

[Summary of the invention]

As a result of intensive studies to eliminate the above-mentioned drawbacks, the present inventor found that when a specific amount of a specific ether ester compound is added to a glass fiber reinforced polyethylene terephthalate resin composition along with a crystallization accelerator, the resulting composition can be heated to a temperature of 100°C. It was discovered that crystallization sufficiently progresses at mold temperatures as low as 6° C., resulting in excellent moldability, and the invention has been completed.

That is, the polyethylene terephthalate resin set # of the present invention
：Product is ：Polyethylene terephthalate resin; 60-900
-90% by weight fiber; 5-60% by weight (C) Nucleating agent 0.03-30% by weight Φ) 0.1-10% by weight of at least one selected from the ether ester compounds represented by general formula CI) However, Ro: Hydrocarbon having 1 or more carbon atoms R, j Hydrocarbon having 2 to 6 carbon atoms R5R4 1 (Rs + "4 is a hydrocarbon having 1 or more carbon atoms) n: An integer of 1 or more or an integer, and) -0) The total amount of each component is 100% by weight.

The polyethylene prephthalate resin (A) used in the invention is a homopolymer of forest-like polyethylene terephthalate having ethylene terephthalate as a constituent unit; a copolymer of the unit component and other copolymerizable components; or,
It refers to a mixed resin of these homopolymers and copolymers, but is not particularly limited to these. here,
As the component that can be copolymerized, conventionally known acid components and glycol components can be used, and specifically, for example, phthalic acid, in7thalic acid, adipine, sebacic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, etc.
Glycol components such as neopentyl glycol, cyclohexane dimetatool, and 2,2-bis(4-hydroxyphenyl)propane; It will be done. The resin can be obtained by a normal polymerization method such as polycondensation of terephthalic acid and ethylene glycol by transesterification or direct esterification, but in this case, the intrinsic viscosity [η] of the resin is set to 0.
It is preferable to set it in the range of 4 to 1.4.

Here, as a method for obtaining a resin having a high intrinsic viscosity, it is also possible to obtain a resin having a relatively low intrinsic viscosity by a conventional solid phase polymerization method. Furthermore, the intrinsic viscosity mentioned here is
This is a value based on the viscosity of a solution measured at 25°C in a solvent of phenol/tetrachloroethane = 50150' (weight ratio). Such polyethylene terephthalate resin is
It is blended in an amount of 30 to 90% by weight in the total resin composition.

! If the IO content is 10% by weight, the fluidity processability decreases, and if it exceeds 90% by weight, the moldability in a low-temperature mold decreases. As the glass fiber used in the present invention, any type of glass fiber such as a roving type or a chopped strand type can be used, but a chopped strand type is preferable from the viewpoint of productivity. In addition, considering workability during mixing of the resin composition of the present invention, wear of the molding machine, and cutting during the molding process, glass fibers having a length of approximately Its length at about 0.2
~2! The range is preferably +1I11. As such glass fibers, commercially available products that have been subjected to various treatments can be used as they are, and the mixing method is not particularly limited. Incidentally, glass fiber accounts for 5 to 6 in the total resin composition.
It is blended in a range of 0% by weight.

When the blending amount exceeds 60% by weight, fluid processability decreases,
If it is less than 5% by weight, the reinforcing effect of the glass fiber will be insufficient.

The nucleating agent (C') used in the present invention has an effect as a nucleating agent for polyethylene terephthalate, such as sodium stearate, fermented calcium stearate, sodium benzoate, calcium benzoate, sodium terephthalate, and terephthalic acid. Group 1 a or group δ metal salts of organic carboxylic acids such as lithium, or monovalent or divalent ionic copolymers of α-olefins and α,β-unsaturated unsaturated norphonates. Metal salts, neutral clays such as talc, zinc oxide, magnesium oxide, calcium silicate, magnesium silicate, calcium sulfate, barium vL acid, and other oxides, sulfates, and silicates of Group II of the periodic table. etc. can be mentioned. These nucleating agents may be used alone or in combination, and are blended in the total resin composition in an amount of 0.03 to 30 wt. In other words, it has a relatively high nucleating effect,
When a metal salt of an organic carboxylic acid is used, the odor is also 0.0.
If it is less than 3% by weight, the excellent heat resistance and appearance improvement effect will be insufficient, and on the other hand, when talc is used, which has a relatively small decrease in strength, it may be necessary to add odor as an inorganic filler. The ether ester compound e) constituting the polyethylene terephthalate resin composition of the present invention is an aromatic divalent compound represented by bisphenol A represented by the general formula (poly)ethylene glycol at both ends of the alcohol,
(Poly)propyv yf IJ :I-yvtx tf
)B\IfFjWcFA(D 21H(1);t: !
J", 1-l is added, and the hydroxyl groups at both ends are further esterified with a monovalent carboxylic acid such as benzoic acid or acetic acid and blocked at °C.0Here, the number of repetitions n is:
It is an integer from 1 to 15, and if it is 15 or more, it is preferable because the reactivity of esterification with carboxylic acid is greatly reduced, a large amount of unreacted hydroxyl groups remain, and this hydroxyl group promotes hydrolysis of the polyester. do not have. That is, for example, those having the following structural formula can be cited.

CH3 CH.

The ether ester compound represented by formula CI) is used alone or in combination, and is blended in an amount of 0.1 to 10% by weight in the total resin composition. If it is less than 0.1% by weight, the effect of promoting crystallization will be insufficient, and if it exceeds 10% by weight, the mechanical strength of the molded product obtained will decrease.

The polyethylene terephthalate resin composition of the present invention may optionally contain various fillers such as wollastonite, mica, glass groups, clay, or kaolin; stabilizers against light or heat; dyes or pigments, etc. It is also possible to add additives.

When manufacturing a molded article from the resin composition of the present invention,
As in the past, a predetermined amount of the composition components is put into an appropriate mixing machine such as an extruder, and after being melted and kneaded to form pellets,
A molded article can be obtained by injection molding or pressure molding. At this time, the feature is that molding can be performed at a mold temperature of 100° C. or less.

In the resin composition of the present invention, the above component (C))
It is necessary to blend the components together with the glass fiber-reinforced polyethylene terephthalate resin, and even if component (C) or component Φ) is blended alone, sufficient effects cannot be obtained.

By using the resin composition of the present invention, it is possible to obtain a polyethylene terephthalate resin molded article with a high degree of crystallinity even at a mold temperature of 100° C. or lower without reducing mechanical strength. Therefore, the resin molded product not only has a high heat distortion temperature but also has excellent properties in terms of moldability, mold releasability, and dimensional stability.

[Embodiments of the invention]

Examples 1 to 8 A polyethylene terephthalate homopolymer having an intrinsic viscosity [η] of 0.72 was added with chopped strand crow fibers of three lengths (abbreviated as OF in the table) and the above (C).
Component (D) was blended in the proportions shown in the table, and mixed for 5 minutes in a Vm blender to homogenize. The obtained mixture was put into a vent type melt extruder having a diameter of 40 m and extruded at a cylinder temperature of 260 to 280°C to obtain pellets of the resin composition of the present invention.

Here, the crystallization rate of the obtained resin composition was measured using a differential calorimeter (DSC), and the
7t) - Using a screw set injection molding machine with a diameter of 45,
At a cylinder temperature of 280°C, a mold temperature of 80°C, and a molding cycle of 60 seconds, the pellet collar 127
Obtain a strip test piece of 6 m in length, and use this test piece to perform AST
The heat distortion temperature (abbreviated as HDT in the table) was measured using M D648 (1/16", 264 psi). Also, under the same molding conditions, 127X12.7X5.
Two baskets of strip specimens were formed and subjected to a bending test according to ASTM D790 at 0°C.
Using the sample obtained at ℃, perform a rapid cooling operation, heat up at 10℃/min in a nitrogen stream, hold at 280℃ for 3 minutes, and cool down at 1
It was carried out under the condition of 0° C./min and determined from the difference ΔT between the crystallization temperature Tc+ when the temperature was raised and the crystallization temperature Tc- when the temperature was lowered. That is, those with a fast crystallization rate show a large value of ΔT and also show a high value of 1/16'' HDT of 165 to 205°C.The results obtained are also shown in the table.

Comparative Examples 1 to 3 Resin compositions were produced in the same manner as in the above Examples, except that the compounds shown in the table were used as additives, and the same tests were conducted. The results obtained are included in the table.

〔Effect of the invention〕

Claims (1)

[Claims] Container polyethylene terephthalate resin 30% to 90% by weight (B) Glass fiber 5% by weight qIb to 60% by weight (C) Nucleating agent 0.05% to 50% by weight Φ) General formula CI) At least one α1 weight S to 10 weight i1% selected from the ether ester compounds represented by R1 + hydrocarbon R having 1 or more carbon atoms, + hydrocarbon 8 having 2 to 6 carbon atoms (R,, R4 is the number of carbon atoms 1 or more hydrocarbons) n+1 to 15
A polyethylene terephthalate resin composition comprising an integer of , and a total amount of each component of ) to ψ) of 100% by weight.