JPS60147466A - Molding of aromatic polyester resin - Google Patents

Abstract

PURPOSE:To obtain articles of improved releasability without impairing mechanical strength, thermal performance and appearance, by attaching a finely powdery specific releasing agent on the surface of pellets or powder of specific aromatic polyester resin. CONSTITUTION:The objective articles can be obtained by blending (A) either powder or pellets of an aromatic polyester resin of formula (R<1>-R<8> are each H, halogen or 1-10C hydrocarbon; X is 1-20C divalent hydrocarbon, O, S, SO etc.; a is 0 or 1) with a logarithmic viscosity 0.2-2.0 with (B) a metallic soap-based releasing agent (at least one sort of salt selected from Mg, Ca, Zn, and Ba salts) and/or fatty acid amide-based one (10-30C fatty acid amide) to attach 200-1,00 (pref. 300-700)ppm of said agent(s) on the surface of said power or pellets.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an aromatic polyester resin molded article having improved releasability from a mold.

Aromatic polyester resins produced from terephthalic acid, isophthalic acid, or their derivatives, and bisphenols or their derivatives have excellent mechanical properties such as tensile strength and flexural strength, thermal properties such as heat distortion temperature, and thermal decomposition temperature. Aromatic polyester resin has excellent performance in terms of electrical properties such as specific resistance, dielectric breakdown, arc resistance, dielectric constant, and dielectric loss, so aromatic polyester resin can be used in extrusion molding, injection molding, and compression molding. It is expected to be molded by methods such as rotary molding and rotary molding, and find wide application in the fields of mechanical parts, aircraft parts, electrical and electronic parts, etc. Molded products in these fields are generally small,
The required dimensional accuracy is strict and the shape is complex. It is difficult to remove such molded products from the mold, as it is not possible to have a sufficient draft angle due to restrictions on dimensional accuracy, and there are restrictions on the position and size of ejector pins depending on the shape of the molded product. .

Furthermore, in the recent molding industry, devices have been developed and used to automatically take out molded products from molds. In order to effectively operate this automatic ejection device, it is necessary to reduce mold release resistance when ejecting a molded product from a mold. Such mold releasability is an important property for resins used as molding materials.

Generally, aromatic polyester resins are amorphous and have a high modulus of elasticity, so mold release is extremely poor.When molding, a release agent is usually applied to the mold or kneaded into the resin. Efforts have been made to improve mold releasability.

However, applying mold release agent to the mold impairs the appearance of the molded product.
This not only lengthens the molding cycle but may also reduce the mechanical strength of the molded product. In addition, the special public
-14584, Japanese Patent Publication No. 57-14385, Japanese Patent Publication No. 14385
No. 7-2554, JP-A-57-2555, JP-A-57
-Fatty acid ester compounds, polyethylene wax, paraffin wax, liquid paraffin, etc., as seen in No. 2356, may cause not only a decrease in performance and contamination of the mold surface, but also devitrification and turbidity in transparent molded products. .

The inventors of the present invention have investigated various methods for manufacturing molded products that have improved release properties without impairing the mechanical strength, thermal performance, appearance, etc. of aromatic polyester resins, and have found that using a finely powdered mold release agent as an aromatic The present invention was completed based on the discovery that by adhering to the surface of group polyester resin, the mold releasability was significantly improved even with the use of a small amount of mold release agent, and the molded products obtained were also good.

That is, the present invention is based on the general formula (1) (wherein 81 ++ FL8 each independently represents a hydrogen atom,
) - is a rogene atom or a hydrocarbon group having 1 to 10 carbon atoms, X is a divalent hydrocarbon group having 1 to 20 carbon atoms, -
〇-1-s-1-8O-1-〇〇- or -802-, and two or more types may be contained at the same time. a is 0 or 1
When it is 0, it shows that the aromatic ring is directly bonded.

The carbonyl groups substituted on the aromatic ring are in the m- and/or p-position relative to each other. n indicates the degree of polymerization. ), and has a logarithmic viscosity in the range of 0.2 to 20, and a metal soap mold release agent and/or a fatty acid amide mold release agent. , is a method for molding aromatic polyester resin, which is characterized by using a finely powdered mold release agent attached to the surface of aromatic polyester resin pellets or powder.

The aromatic polyester resin used in the present invention is
It is produced from a mixture of terephthalic acid and isophthalic acid or their functional derivatives, and bisphenols such as bis(hydroxyphenyl)sulfone and bis(hydroxyphenyl)propane, or a mixture thereof. <No.S31, JP-A-58-59
No. 218, Japanese Patent Publication No. 58-59219, Special Publication No. 49-1
It can be easily produced by the method described in Japanese Patent Publication No. 5065, Japanese Patent Publication No. 49-15066, etc.

The metal soap-based mold release agent used in the present invention includes magnesium, aluminum, fatty acids having 10 to 30 carbon atoms,
It is one or a mixture of two or more salts of calcium, zinc or barium, and the fatty acids include capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid,
Examples include pentadecyl acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lig/-1z IJ acid, cerotic acid, heptacic acid, montanic acid, melisic acid, and lafcelic acid.

The fatty acid amide mold release agent used in the present invention is an amide of a fatty acid having 10 to 60 carbon atoms, and specifically, lauric acid amide, myristic acid amide, palmitic acid amide, heptadecylic acid amide, and stearic acid amide. Examples include monoamides such as amide, nonadecanoic acid amide, montanic acid amide, oleic acid amide, erucic acid amide, stearolic acid amide, and methylene and ethylene dimers of these monoamides, and these may be used alone or in combination of two or more. used.

In the present invention, the amount of these mold release agents attached to the surface of the aromatic polyester resin is 20% relative to the aromatic polyester resin.
0-11000 pp, preferably 600-700 pI
)m. If the amount is less than this, a molded product with good mold releasability cannot be obtained; If it is deposited in excess of 00 pI)m, mold releasability will be sufficient, but the mechanical strength and thermal performance of the molded product will decrease, the mold surface will be stained, and in the case of transparent products, it may become cloudy. This is not desirable as it may cause problems such as

The method for molding the aromatic polyester resin of the present invention is as follows: 1) After mixing the aromatic polyester resin powder and a mold release agent in a mixer such as a Henschel mixer, and adhering the mold release agent to the surface of the resin powder, Method of molding with an injection molding machine, etc., 2) Before molding such as injection molding, aromatic polyester resin pellets and a mold release agent are mixed in a mixer such as a ribbon blender, and a release agent is applied to the surface of the resin pellet. There is a method in which the material is attached and then molded using a molding machine.

The molding method of the present invention is superior to a method in which aromatic polyester resin powder is mixed with a metal soap mold release agent and/or a fatty acid amide mold release agent and molded using pellets extruded by an extruder. The soap-based mold release agent and/or the fatty acid amide-based mold release agent undergoes only one heat history, which not only increases the mold release property improvement effect for the added amount, but also improves the mold release property required during actual molding. It has the advantage that it can be easily adjusted by changing the amount of non-deposition.

In the present invention, fillers such as talc, calcium carbonate, mica, and glass peas, fibrous reinforcing materials such as glass fiber, carbon fiber, and aramid fiber, stabilizers, ultraviolet absorbers, and coloring are added to the aromatic polyester resin as necessary. Agents may be mixed as long as the quality of the resin composition is not deteriorated.

The present invention will be specifically explained below using Examples.

Note that the logarithmic viscosity η,,,nA is 0511
/dll solution.

Examples 1 to 4, Comparative Examples 1 to 6 A dichloromethane solution of mixed acid chloride with a molar ratio of terephthaloyl chloride and isophthaloyl chloride of 1=1, 2,2-bis(4-hydroxyphenyl)propane and bis An aromatic polyester resin was produced from an alkaline aqueous solution of (4-hydroxyphenyl)sulfone by an interfacial polymerization method. The molar ratio of 2,2-bis(4-hydroxyphenyl)propane and bis(4-hydroxyphenyl)sulfone was 1:1. The logarithmic viscosity of the obtained tree layer was 0.65, and the NMR spectrum showed that 2
, 2-bis(4-hydroxyphenyl)furopane and bis(4-hydroxyphenyl)sulfone in an abundance ratio of about 1:1.

The aromatic polyester resin thus obtained was pelletized using a single-screw extruder with a diameter of 30 mm at a cylinder temperature of 640°C. Calcium stearylate was deposited on the surface of this pellet in the amount shown in Table 1. The pellets were molded into a small cylindrical container with an outer diameter of 20 mm using an injection molding machine under conditions of a cylinder temperature of 570°C and a mold temperature of 150°C.

At that time, a strain gauge was installed on the protruding plate, and the mold release resistance of the molded container from the mold was measured. The appearance of the container was observed. The results are shown in Table-1.

Table 1 Examples 5 to 8 Adhering to the surface of aromatic polyester resin pellets in the same manner as in Example 1 except that magnesium stearate, zinc stearate, barium stearate, or calcium montanate was used instead of calcium stearate. I forced it. The mold release resistance and appearance of this composition were examined. The results are shown in Table-2.

Table 2 Examples 9 to 12 Stearamide instead of calcium stearate,
It was adhered to the aromatic polyester resin pellet surface r in the same manner as in Example 2 except that palmitic acid amide, oleic acid amide or erucic acid amide was used. The mold release resistance and appearance of this pellet were examined. The results are shown in Table 3.

Table 3 Comparative Example 4 200 ppm of calcium stearate was added to the aromatic polyester resin obtained in Example 1, mixed in a Henschel mixer, and pelletized using a single screw extruder with a diameter of 60 at a cylinder temperature of 340'C. It became. Next, use this pellet? The mold release resistance and the appearance of the molded product were examined in the same manner as in 111. The mold release resistance was 76 kg, and the appearance was good.

Comparative Examples 5 to 6 Low molecular weight polyethylene “Sunwax 151pJ (trademark) was added to the aromatic polyester resin obtained in Example 1.
manufactured by Sanyo Chemical Industries, Ltd.) or microcrystalline wax "Varico Microcrystalline Wax" (trademark manufactured by Toyo Ink Mfg. Co., Ltd.) at 1 o o o ppr1.
% and mixed with a Henschel mixer, and then pelletized using a single screw extruder with a diameter of 60 at a cylinder temperature of 330°C.

Using this pellet, mold release resistance and appearance of the molded product were examined in the same manner as in Example 1. The results are shown in Table 4.

Claims (1)

[Scope of Claims] 1) General formula (1) (In the formula, 1 to R8 are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 1 carbon atoms, and X is a hydrocarbon group having 1 to 20 carbon atoms. 21! Hydrocarbon group, -0-1-s-1
-8O-1-ao- or 7sO,-, and two or more types may be contained at the same time. a indicates 0 or 1, and when it is 0, it indicates that the aromatic rings are directly bonded. The carbonyl groups substituted on the aromatic ring are mutually in the In- and/or p-positions. n indicates the degree of polymerization. ),
When molding an aromatic polyester resin composition consisting of an aromatic polyester resin having a logarithmic viscosity in the range of 0.2 to 2.0 and a metal soap mold release agent and/or a fatty acid amide mold release agent, the aromatic polyester A method for molding an aromatic polyester resin with good mold release properties, characterized by using a finely powdered mold release agent attached to the surface of a resin pellet or powder. 2) The molding method according to claim 1, wherein the amount of the mold release agent deposited is 200 to 11,000 pp with respect to the aromatic polyester resin. 3) A patent claim characterized in that the metal soap mold release agent is one or a mixture of two or more salts of magnesium, aluminum, calcium, zinc or barium of 711 fatty acids having 10 to 30 carbon atoms. The molding method according to scope 1 or 2. 4) The molding method according to claim 1 or 2, wherein the fatty acid amide mold release agent is an amide of a fatty acid having 10 to 30 carbon atoms.