JPS59157145A - Polyethylene terephthalate resin composition - Google Patents

Abstract

PURPOSE:The titled composition having high heat distortion temperature without lowering mechanical strength, providing a molded article having improved releasability, etc., obtained by blending a polyethylene terephthalate resin with a mono-, di-, or polybenzoate of a specific polycaprolactone and a metal salt of organic carboxylic acid. CONSTITUTION:(A) 30-85wt% polyethylene terephthalate is blended with (B) 5-60wt% glass fibers, (C) 0.03-5wt% at least one organic acid metal salt of I a or IIa group of periodic table, and (D) 0.1-20wt% mono-, di-, or polybenzoate of polycaprolactone having 300-5,000, preferably 500-2,000 number-average molecular weight. The component B is glass fibers of chopped strand type and used in such a way that 0.4-6mm. glass fibers are processed into 0.2-2mm. glass fibers in a final molded article. Sodium stearate, sodium benzoate, etc. is preferable as the component C.

Description

DETAILED DESCRIPTION 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.

It is known that glass Hh fiber reinforced products of polyethylene terephthalate resin have excellent mechanical properties, chemical resistance, etc. 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 resulting resin has poor moldability, and has a heat deformation temperature of around 100°C and poor heat resistance.

Therefore, as methods for promoting crystallization, there are two methods: post-processing heat treatment of the molded product in a partially solidified and compacted state to promote crystallization, and a method in which the molded product is placed in a liquid that promotes crystallization. A method of immersing the molded product has 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.

Therefore, in the past, instead of the method described in -1-, the only option was to maintain the mold temperature at a high temperature of 120 to 150°C to promote crystallization during the molding process.
However, this method had disadvantages in terms of efficiency and work safety because it required the use of a mold at high temperatures.

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.

However, even with this method, the defects listed in 1-1 cannot be fully resolved, and when molding is performed at a mold temperature of 100°C or less, a long cooling time is required, and the releasability of the molded product is poor. Getting worse. Furthermore, since the crystallinity of the resulting molded product is low, reducing the wall thickness of the molded product will result in insufficient heat resistance, and if this molded product is used in a high-temperature atmosphere, crystallization will progress and post-shrinkage may occur. This has the drawback of causing the dimensional stability to deteriorate.

The present invention eliminates the following drawbacks and makes it possible to produce molded products that have a high heat deformation temperature and excellent moldability, mold releasability, and dimensional stability without reducing mechanical strength. The purpose of the present invention is to provide a highly crystalline polyethylene terephthalate resin composition.

As a result of intensive studies in order to eliminate the above-mentioned drawbacks, the present inventors have found that mono-, di-, or polybenzoic acid esters of polycaprolactin in a specific molecular star range are used as crystallization accelerators to form glass fiber-reinforced polyethylene terephthalate. When a specific μ is added to a resin composition, the resulting composition undergoes sufficient crystallization even at a mold temperature of 100°C or less, has excellent moldability, and the molded product has a high heat distortion temperature. This discovery led to the completion of the present invention.

That is, the polyethylene terephthalate resin composition of the present invention has (A) polyethylene terephthalate resin; 30-85
Weight % (B) Glass fiber; 5 to 60 weight % (C) At least one metal salt of Group 1 a or Group 1 I a of the periodic table of organic carboxylic acid: 0.03 to 5 weight % (D) Mono-, di-, or polybenzoic acid diester of polycaprolactone having a number average molecular weight in the range of 300-5000; 0.1-20% by weight, the total amount of each component (A) to (D) ,i,<
It is characterized by 100% heavy welfare.

The polyethylene terephthalate resin (A) used in the present invention refers to a homopolymer of ethylene terephthalate, ray, and linear borie, tylene terephthalate, and terephthalate as structural units; other copolymerizable components , such as phthalic acid, isophthalic acid 1, adipic acid, sebacic acid, p-β
- Acids such as oxy, ethoxy antate, folic acid or propylene glycol, butanediol, tetramethylene gel 6
Recall, hexamethylene gel 1. ? Copolymers with glycols such as coal, neopentyl glycol, and dodecamethylene glycol; or mixed resins of these homopolymers and copolymers; and the like, but are not particularly limited to these. The resin can be obtained by a conventional polymerization method such as polycondensation of terephthalic acid and ethylene glycol by transesterification or direct esterification, but in this case, the intrinsic viscosity of the resin [η
] is preferably set in the range of 0.4 to 1.4.

In order to obtain a resin having a high intrinsic viscosity, it is sufficient to carry out the polymerization reaction described above for 1 degree using a conventional solid phase polymerization method.

In addition, the characteristic 4 degree mentioned here means phenol/tetrachloroethane = 50150 (weight ratio) in cy2 solvent, 2
This is the value determined from the viscosity of the solution measured at 5°C - p). Such polyethylene terephthalate resin is blended in an amount of 30 to 85% in the total resin composition. 30 double questions%
If it is less than 85 times, the flow processability will deteriorate, and if it exceeds 85 seams, the effects of the present invention cannot be achieved.

As the glass fiber used in the present invention, any type of glass fiber such as roving type or chopped strand type can be used, but from the viewpoint of productivity,
A strand type is preferred. Furthermore, considering the workability, t&Mlj, wear of the machine, and cutting during the molding process during mixing of the resin composition of the present invention, 1. When mixing glass #I & fiber having a length of about 0.4 to 6 cm, use 1. Preferably, its length in the final molded product is in the range of about 0.2 to 2 cm. As the darkened glass fiber, commercially available products that have been subjected to various treatments can be used as they are. In addition, the glass fiber contains 5 to 80 weight i5 in the total resin composition.
It is blended within the range of %. If the content exceeds 60% by weight, fluidity deteriorates, resulting in poor moldability. Also,
If the weight is less than 5%, the reinforcing effect of the glass fiber will be insufficient.

The organic carboxylic acid used in the present invention is a metal salt of organic carboxylic acid, which is used for metals in Group 1 a or Group 1 I a of the periodic table, and acts as a nucleating agent for polyethylene terephthalate resin. may be either an aliphatic or aromatic carboxylic acid, and there are no particular restrictions on the type of metal in Group I a or Group I I a of the Periodic Table. Specific examples of metal salts of 11-carboxylic acids include For example, sodium laurate, potassium laurate, sodium myristic acid, butypotassium myristic, sodium chloride stearate, potassium ophthalcodium, calcium myristileate, calcium stearate, sodium chloride benzoate, and terephthalate. Examples include butypotassium and lithium terephthalate, but these metals 11, (among them, stearate, stearate, lithium terephthalate, etc.
, An, B, Potassium fragrant 1\ and Potassium terephthalate '9 are preferred. These IJ machine carbon alcohol metal 1
j is also used in China and Germany, and is blended in the range of 0.03 to 5% in the composition. 0.

If it is less than 1%, good heat resistance and mold release properties cannot be obtained, and if it exceeds 5%, the mechanical strength of the finished product will be reduced.

The mono-, di- or polyammonium 71.4 of polycaprolough used in Kineri J, and aroma-resistant esters include, for example, polyols (e.g., ethylene glycol, propylene glycol, neopentyl glycol lycerate 7'). ．'；：
) is used as a catalyst to ring-open caprolactone (δ, ε, etc.) or the lactone is subjected to ring-opening polymerization, and the terminal OH group of the resulting polymer is esterified with benzoic acid. . Rest fFM esdertositeha, number W' equal molecular Il; Ka3oθ~5oooinoII11! A number in the range of 500 to 2000 is preferably used. these are? iUsed alone or in combination. Even if the number average molecular hI is relatively low at 300 to 1000, the molded product exhibits an excellent crystallization promoting effect without reducing the mechanical strength of the molded product. On the contrary, the number
- As the homogeneous molecular weight product becomes larger, the crystallization promoting effect becomes smaller, and when the several-quadruple homogeneous molecular injury exceeds 500θ, no significant crystallization promoting effect can be obtained. Moreover, the benzoic acid ester is blended in the range of 0.1 to 20% in the total resin composition.

If the amount of 0 and 1 is less than %, the crystallization promotion effect will be insufficient.
If it exceeds 20% by weight, the mechanical strength of the molded product obtained will decrease.

Unlike untreated polycaprolactone, the mono-, di-, or polybenzoic acid ester of polycaprolactone has a benzoyl group at the terminal group, and therefore has good compatibility with polyethylene terephthalate and has a large crystallization promoting effect. In addition, since the terminal OH group is esterified to prevent polyethylene terephthalate 1-11M, the mechanical strength of the molded product will not be reduced.

The polyethylene terephthalate resin composition of the present invention may optionally contain various fillers such as talc, mica, crow powder, clay or cao, and 1-non; stabilizers against light or heat; dyes or pigments, etc. This is only possible by adding additives.

When manufacturing a molded product from the resin M1 composition of the present invention, the prescribed (11) composition components are put into an appropriate kneading machine such as an extruder, and the mixture is melted and kneaded in the same manner as before. Te Pele 7
1, and then subjected to injection molding or pressure molding to obtain a molded product. At this time, the feature is that molding can be performed at a mold temperature of +00°C or higher.

It should be noted that the effects of the present invention cannot be obtained with epoxy compounds; This can only be obtained by using carboxylic acid metal 11 in combination.

Below 1. As explained above, the resin composition of the present invention can be used to produce polyethylene terephthalate resin molded products with high crystal retention even when the mold is warmed at 100°C or higher, without decreasing the mechanical strength. Obtainable. For this reason, the resin molded product not only has a high heat deformation temperature but also has poor moldability.
It also has excellent properties in terms of mold releasability and dimensional stability.

The present invention will be explained below with reference to Examples.

゛ Examples 1 to 8 A polyethylene terephthalate homopolymer having an intrinsic viscosity [η] of 0.72 was added with a 3 mo long Chiyo 2-buto strand glass fiber (abbreviated as GF in the table) and the above (C
) (D) Components were blended in the proportions shown in the table, and mixed for 5 minutes in a V-type blender to homogenize. The obtained mixture was put into a vent type melt extruder having a diameter of 85+ am and extruded at a cylinder temperature of 260 to 290°C to obtain pellets of the resin composition of the present invention.

Here, using a differential calorimeter (DSC), the crystallization temperature Tc+ at the time of heating up and Tc- at the time of cooling down of the pellet in a nitrogen stream were measured, and the crystallization rate ΔT (= Tc
--T c″°) was determined.For measurement, 10°C
The temperature was raised at a rate of 10° C./min, held at 280° C. for 3 minutes, and then lowered at a rate of 10° C./min. The results obtained are also listed in the table. Note that the crystallization rate is faster as Tc is lower and ΔT+ is larger.

Next, 3 ounces (85 g) + 1 diameter 3 o II 1 ml nozzle screw set injection using a J& type machine, cylinder temperature 280
A strip specimen of 127 x 12.7 x 3.2 mm was obtained from the pellet at a mold temperature of 80° C. and a molding cycle of 30 seconds. Using this test piece, ASTM 0
848 (1/8", 264 psi) (abbreviated as HOT in the table) and ASTM D-
The bending properties were measured using 71110. The results obtained are also listed in the table.

Comparative Examples 1 to 5 Pellets and test pieces were produced in the same manner as in the above example except that the compounds shown in the table were used as additives,
An identical test was conducted. The results obtained are also listed in the table.

Claims (1)

[Claims] (A) Polyethylene terephthalate resin; 30-85
Weight % CB) Glass fiber; 5 to 60 weight % (C) At least one metal salt of group 1 a or group 1 I a of the periodic table of carboxylic acid; 0.03 to 5 biwat % (D) Mono-, di-, or polybenzoic acid ester of polycaprolactone having a number average molecular weight in the range of 300 to 5,000; 0.1 to 20% by weight, and the total dispersion of each component of (A) to (D) is 100% by weight. Polyethylene terephthalene, characterized in that it is %
) type resin composition.