KR930008192B1 - Polyester resin composition - Google Patents

Abstract

This new polyester resin composition has fast crystalization speed and good parting and surface lustering when molding at below 110 deg.C. The polyester composition comprises: reinforced polyethylene terephthalate; good dispersive inorganics of 0.1-10

Description

Polyester resin composition

The present invention relates to a thermoplastic polyester resin composition having a high crystallization rate, molding at a molding temperature of 110 ° C. or less, and having excellent physical properties and excellent releasability and surface gloss.

Polyethylene terephthalate resin has excellent mechanical properties, chemical resistance, electrical properties and heat resistance, so it is widely used in electrical insulation parts, automotive parts, and the like in electrical and electronic fields, and it has various functions such as reinforcing agents, flame retardants, and impact agents. The use expands further by adding.

However, the polyethylene terephthalate resin has many difficulties in crystallization when used in the plastic field, despite excellent mechanical properties, electrical properties, heat resistance, chemical resistance. In other words, in order to obtain a molded article having good surface gloss and releasability and having various properties of polyethylene terephthalate resin, a high molding temperature of 130 ° C. or higher should be used. Low, long molding time is required.

Polyethylene terephthalate resin is a crystalline resin, and its properties mainly depend on the degree of crystallinity. When the polyethylene terephthalate resin is molded at a molding temperature of 130 ° C. or higher, a molded product having excellent release properties and surface properties, and excellent mechanical properties and heat resistance can be obtained. However, since most molding machines use molding heat treatment as water during molding, the usable temperature is Since it is 80-110 degreeC, it is difficult to actually apply high temperature more than 130 degreeC.

Therefore, it is required to produce a reinforced polyethylene terephthalate resin capable of obtaining a molded article having excellent releasability and surface properties, high crystallinity and fast crystallization rate at a molding temperature of 110 ° C. or lower.

For this purpose, a lot of additives for increasing the crystallinity and improving the rate of crystallization have been researched and published for the purpose of improving the moldability of polyethylene terephthalate resin.

For example, UK Patent Nos. 2,015,014 and US Pat. No. 4,440,889 use solid inert inorganics and metal salts of Group I or Group II of mono- or polycarboxylic acids as crystal nucleators and crystal promoters at molding temperatures of up to 110 ° C. It was shown that molding was possible.

However, the addition of these materials requires the addition of a large amount of additives in order to obtain a molded article having good releasability and surface properties when molded at a temperature of 110 ° C. or below, and at a large amount, the mechanical strength is lowered and heat resistance is high. This has the disadvantage of falling.

Therefore, it is an object of the present invention to produce a polyethylene terephthalate resin composition which can obtain a molded article having excellent releasability and surface properties and excellent mechanical strength and heat resistance even when molded at a molding temperature of 110 ° C. or lower.

In other words, the present invention is a reinforced polyethylene terephthalate resin 1) inorganic dispersion of excellent particle diameter of 0.1 ~ 10μ, 2) the sodium, potassium or zinc salt of organic materials containing reinforcing agent alone or mixed use and 3) containing carboxyl group Sole or mixed use of sodium, potassium or zinc salts of organic matter, and 4) polyamides represented by the following formula (I):

(In Formula (I), R ₁ is hydrogen, an alcohol group or a carboxyl group, R ₂ is a hydrocarbon having 1 to 20 carbon atoms, R ₃ is hydrogen or a hydrocarbon having 1 to 30 carbon atoms, R ₄ is hydrogen, an amine group or Alcohol group, n is an integer of 2 or more.)

It is characterized by being a resin composition composed of.

The polyethylene terephthalate resin used in the present invention is a polymer obtained by a conventional esterification reaction or transesterification reaction based on terephthalic acid or dimethyl terephthalate and ethylene glycol, and has an intrinsic viscosity when measured in ortho-chlorophenol at 35 ° C. Is between 0.5 and 0.9.

The polyethylene terephthalate may contain a small amount of polymerization byproducts such as diethylene glycol or glutaric acid, and the intrinsic viscosity has an upper limit of about 1.2 by a conventional polymerization method.

However, the intrinsic viscosity of the polyethylene terephthalate resin suitable for the present invention is suitable to have a value of 0.5 ~ 0.9 when measured in ortho-chloro phenol at 35 ℃.

If the intrinsic viscosity is 0.5 or less, the physical properties of the molded article is significantly lowered. If the intrinsic viscosity is 0.9 or more, the melt viscosity is high, the moldability is poor, the surface is rough, and the gloss is poor.

The reinforcing agent used in the present invention may be a fiber type having a thickness of 50 μ or less and 0.1-20 mm in length, carbon fiber, glass fiber, or aramid fiber, and as inorganic filler, talc (main component 3MgO 4SiO ₂ nH ₂ O), kaolin (main component Al ₂ O ₃ 2SiO ₂ 2H ₂ O), asbestos, mica, silica, clay, gypsum and the like.

These may be used alone or in combination, and the amount of reinforcing agent added is suitably 5 to 100 parts by weight based on 100 parts by weight of polyethylene terephthalate.

In order to promote the crystallization of the polyethylene terephthalate resin, an inorganic material having a particle size of 0.1 to 10 mu is used. As the composition of the present invention, the inorganic material usable is excellent in dispersibility so that crystallization can occur at the same time in the composition, and such materials include mica, silica, mica, calcium carbonate, talc, kaolin, calcium phosphate, magnesium carbonate and calcium sulfate. Barium sulfate, zinc oxide, magnesium oxide, silicon, iron oxide, calcium stannate and the like.

The amount of the inorganic substance added in the present invention is 0.05 to 10 parts by weight, preferably 1 to 5 parts by weight based on 100 parts by weight of polyethylene terephthalate.

If the amount of the added inorganic matter is 0.05 parts by weight or less, crystal nucleation does not occur uniformly. If it is 10 parts by weight or more, there is no further effect and the physical properties are significantly reduced.

As the sodium, potassium or zinc salt of the carboxyl-containing organic substance used in the present invention, preferably a metal salt of a fatty acid having 10 to 30 carbon atoms and an aromatic acid having 20 or less carbon atoms and a 20 to 90% neutralized α-olefin hydrocarbon; metal salts of copolymers of α, β-unsaturated carboxylic acids.

Typical examples of such fatty acids and aromatic acids include stearic acid, behenic acid, benzoic acid, montanic acid, halogenated benzoic acid, and the like. In addition, α-olefin hydrocarbons include ethylene, propylene, 1-butene, styrene, and the like. and α, β-unsaturated carboxylic acids include acrylic acid, methacrylic acid, 4-butene acid, maleic anhydride and the like.

Examples of the metal salt of the copolymer of the α-olefin-based hydrocarbon and the α, β-unsaturated carboxylic acid include sodium, potassium or zinc salts of ethylene / acrylic acid, ethylene / methacrylic acid, propylene / maleic anhydride and styrene / maleic anhydride copolymers. .

The metal salts of such organic acids may be used alone or in combination, and the addition amount is 0.1 to 10 parts by weight with respect to 100 parts by weight of polyethylene terephthalate, preferably 1 to 5 parts by weight.

As a composition of the present invention, the polyamide having a degree of polymerization of 2 or more lowers the secondary transition temperature of polyethylene terephthalate and increases the crystallization rate, thereby improving the releasability and surface glossiness of the molded article and improving the crystallinity when molded at a molding temperature of 110 ° C. or lower. It works.

Examples of such a material include polycaprolactam, poly-N-methyl-3-amino propionate, poly decamethylene oxamide, polyethyleneadipamide, polyhexamethylene alpamide, polyhexamethyleneoxamide, and poly tetramethylene dodecane-di -Amide, poly-4,4'-di-phenylene adiamide, polyethylene terephthalamide, polyhexamethylene terephthalamide, polytetra methylene terephthalamide, poly-1, 4-cyclohexylene-3,3'- Such as di-benzoamide.

In the present invention, the amount of polyamide having a degree of polymerization of 2 or more is suitably 0.1 to 20 parts by weight, and preferably 2 to 10 parts by weight based on 100 parts by weight of polyethylene terephthalate. If the added amount is less than the appropriate amount, it does not exhibit a substantial effect of promoting the rate of crystallization, and if it is more than the appropriate amount, it does not show any further crystallization promoting effect.

In the compositions of the present invention, additives such as flame retardants, colorants, mold release agents, antioxidants, plasticizers, ultraviolet stabilizers, heat stabilizers, lubricants, and the like may be included in addition to the components discussed above to improve other properties of the polyethylene terephthalate resin composition. have.

Polyethylene terephthalate resin composition according to the present invention can be molded at a molding temperature of 110 ℃ or less, can make a molded article excellent in crystallinity, can provide a molded article excellent in dimensional stability and surface gloss and heat resistance.

In the present invention, the mixing of the composition may be performed during polymer polymerization or in a polymer molten state, but in the present invention, a sufficiently dried polyethylene terephthalate resin and the composition are melt-extruded at 290 ° C. using a twin screw extruder.

In addition, the extruder is recommended to remove the impurities generated during melt extrusion by installing a trap in a high vacuum state in order to take advantage of the characteristics of the molded article.

In the present invention, a method of measuring the crystallization rate is heated by using a differential scanning calorimeter (DSC Cell) connected to a DuPont 900 differential thermal analyzer (Dupont 900 DTA) and heating the molded specimen and heating point (Tic, temperature rising between 90 ~ 140 ℃) Crystallization temperature).

After heating the molded specimen to 290 ℃ (above the melting point of the molded specimen), the heating point (Tmc, temperature crystallization temperature) between 190 ~ 220 ℃ is recorded while cooling the molten sample at 10 ℃ / min. Judging by (Tmc-Tic) and Tic.

As the difference between the heating points (Tmc-Tic) is higher than 100 ° C and the Tic is lower, the crystallization rate and crystallinity in the low temperature mold increase.

Hereinafter will be described in detail based on the embodiment of the present invention.

However, the scope of the present invention is not limited based on the examples.

Example 1

Polyethylene terephthalate resin having an intrinsic viscosity of about 0.65 was used after drying at 130 ° C. for 5 hours using a dehumidifying dryer, 64.2 wt% polyethylene terephthalate, 0.5 wt% talc with a particle diameter of 4.4 μ, and 1.5 wt% of ethylene / sodium methacrylate %, 3.0 wt% polytetramethylene terephthalamide with polymerization degree 20, 30 wt% glass fiber 3mm long, 0.1 wt% antioxidant, 0.2 wt% dioctylphthalate as gaseous agent and 0.5 wt% epoxy compound in noblelock to 290 ° C. Simultaneously put into a heated twin screw extruder, melt mixed and extruded into chips. The chip was placed in a dehumidifying dryer at 130 ° C. and dried for at least 5 hours, followed by injection molding using a 5 ounce injection molding machine under the following conditions. The cooling time was 25 seconds and the molding time was 37 seconds. Property evaluation results of the molded article are shown in Table 2.

Mold temperature: 95 ℃

Cylinder temperature: 275 ℃

Injection pressure: 500 ~ 800Kg / Cm ²

[Examples 2 to 7 and Comparative Examples 1 to 5]

The composition of the composition implemented in Examples 2-7 and Comparative Examples 1-5 was shown in Table 1. Polyethylene terephthalate had an intrinsic viscosity of about 0.61 to 0.75 and was dried at 130 ° C. for at least 5 hours. Glass fiber was used to produce Ildongbang 3J-941 cut to a length of 3 mm, and talc was 4,4μ. Particle diameters were used, and ethylene / sodium acrylate salts and ethylene / sodium methacrylate salts were 60-95% neutralized to extrude chips using a twin screw extruder at a melt temperature of 290 ° C. and 10-25 mmHg vacuum. The chip thus obtained was injection molded under the same conditions with a 5 oz injection molding machine in the same manner as in Example 1.

* Assessment Methods

1) tensile strength

It measured according to ASTM D-638.

2) crystallization temperature

Record the heating point (Tic) between 90 and 140 ° C while heating the molded specimen using a differential scanning analysis (DSC). Subsequently, the molded specimen was heated to 290 ° C. (above the melting point of the molded specimen), and then the heating point (Tmc) between 190 ° and 220 ° C. was recorded while cooling the molten sample at a rate of 10 ° C./min to determine the crystallization temperature difference (Tmc). -Tic) was calculated. The larger the difference between the low temperature crystallization temperature (Tmc) and the elevated temperature crystallization temperature (Tic), the lower the elevated temperature crystallization temperature (Tic), the faster the crystallization rate in the low-temperature mold.

3) dysplasia

When the injection test was carried out 30 times, the number of times the injection specimen fell without sticking to the mold was measured.

4) heat deflection temperature

According to ASTM D-648, the thickness of the molded specimen was measured at 1/8 inch with a load of 18.6Kg / Cm ² .

TABLE 1

Claims (1)

Reinforcing agent such as 0.05 to 10 parts by weight of inorganic material having excellent dispersibility of particle size of 0.1 to 10 microns and fiber reinforcing agent such as glass fiber, etc., based on 100 parts by weight of polyethylene terephthalate having intrinsic viscosity of 0.5 to 0.9 as measured in 35 ° C. ortho-chlorophenol. Polyester, characterized in that consisting of 0.1 to 10 parts by weight of polyamides having a polymerization degree of 2 or more, such as the following formula (I), by weight or by using sodium, potassium or zinc salts of organic substances containing carboxyl groups alone or in combination. Resin composition.

(In Formula (I), R ₁ is hydrogen, an alcohol group or a carboxyl group R ₂ is a C1-C20 hydrocarbon R ₃ is hydrogen or a C1-C30 hydrocarbon, R ₄ is a hydrogen, an amine group or an alcohol group, n is Is an integer of 2 or greater.)