KR100194013B1 - Poly (1,4-cyclohexylenedimethylene terephthalate) resin composition having excellent heat resistance and microwave resistance - Google Patents

Abstract

The present invention is a poly (1,4-cyclohexylenedimethylene terephthalate) resin composition, which is composed of ethylene bis-tetrabromophthalimide flame retardant, polyphenylene sulfide resin and mica, talc, ulastonite, barium sulfate and the like. By containing the inorganic filler, the heat resistance and the microwave resistance are greatly improved, and when used in a rotary ring of a microwave oven, the present invention relates to a resin composition which does not change or discolor even in a no load test.

Description

Poly (1,4-cyclohexylenedimethylene terephthalate) resin composition having excellent heat resistance and microwave resistance

The present invention relates to a poly (1, 4-cyclohexylene dimethylene terephthalate) (hereinafter referred to as PCT) resin composition, in particular, excellent heat resistance and micro-resistant that can be used in a rotary ring of a microwave oven, etc. It relates to a PCT resin composition having a wave property.

PCT is a crystalline polyester that has excellent mechanical properties, heat resistance, chemical resistance, durability at high temperature and high humidity, and in particular, dielectric breakdown strength and electrical properties are kept constant even in the high temperature region. By using these characteristics, their use is expanding for electric and electronic parts and automobile parts requiring heat resistance. In addition, polybutylene terephthalate resin and polyethylene terephthalate resin, which were used in the field of battery electronics, cannot be applied to new fields such as surface mount technology requiring heat resistance of 260 ° C or higher. The use of PCT resins, which are advantageous in terms of cost, is increasing.

The PCT resin obtained by the polycondensation reaction can be used alone, but PCT resin composition which is endowed with flame retardancy, high rigidity and desired properties by adding glass fiber, inorganic fiber, flame retardant and various additives using a single screw and twin screw extruder can be used. Mainly used.

Polyphenylene sulfide resins are widely used in electric and electronic parts and automobile parts because of their excellent heat resistance, chemical resistance and mechanical properties. Particularly, when subjected to heat, a crosslinking reaction occurs in the presence of oxygen, which results in more excellent characteristics. However, the price is expensive and dark brown, so it is difficult to display various colors.

In the present invention, a combination of the advantages and disadvantages of the two plastics has been developed a product that can exhibit a low price and excellent physical properties and various colors.

Microwave ovens to which the composition developed in the present invention is applied are classified into two types according to their functions. One is to cook food using only microwave as a single function model, and the other is to cook food using heat generated from microwave and heater as a multifunctional model. In the case of a short function model, materials with low heat resistance, such as polypropylene, can also be used as a rotary ring. However, in the case of the multifunctional model, the temperature inside the microwave oven may rise to about 280 ° C. or more during operation, and therefore a high heat resistant resin such as polyphenylene sulfide (PPS) is mainly used.

No load test is performed for use as a rotary ring in a microwave oven. This is a method of driving a microwave oven in a state in which no food is put in the microwave oven and a rotating ring and a glass plate on which the food is placed thereon. As the test progresses, the temperature of the glass plate and the rotating ring rises by the heater and the microwave. In particular, the portion of the rotating ring close to the glass plate increases in temperature, causing discoloration and deformation.

In Japanese Patent Publication No. 46-2086, flame retardancy was imparted to a glass fiber reinforced polyester resin by adding decabromodiphenyl ether and antimony trioxide as flame retardants and flame retardant aids. However, when the flame retardant is used in PCT resin, surface expansion and severe discoloration occur in the microwave no load test.

Korean Patent Publication No. 95-8900 discloses a phenoxy resin or an epoxy resin which serves as a functional imparting agent to a blend composition of a polybutylene terephthalate resin and a polyphenylene sulfide resin, which are basic resins, in order to improve the heat resistance of a polyester resin. The addition of tetrabromobisphenol acarbonate carbonate oligomer as a flame retardant and sodium antimonate (NaSbO ₃ ) as a flame retardant adjuvant and the invention of the thermoplastic composition which are excellent in heat resistance and are not blooming is reported.

However, even if the heat resistance of the PCT resin is improved in this way, problems such as surface expansion, appearance deformation, and discoloration occur when used in the rotary ring of the microwave oven. In particular, discoloration and surface swelling occur more seriously when an epoxy resin as a functional imparting agent is added to increase physical properties.

It is an object of the present invention to provide a PCT resin composition that is free from discoloration and deformation, and is free of cost and competitive in use when used as a rotary ring of a microwave oven.

As a result of efforts to achieve the above object, the present inventors found a combination and content of a flame retardant, a polyphenylene sulfide resin and an inorganic filler having a synergistic effect, and applied it to a PCT resin, thereby turning into a rotary ring of a microwave oven. The present invention has been completed by finding out that the PCT resin composition can be freely discolored and deformed, free of coloring, and competitive in price.

Specifically, the composition of the present invention contains the following components.

(A) 15-55 weight% of PCT resin.

(B) 5 to 20% by weight of flame retardant.

(C) 1 to 10% by weight of flame retardant aids.

(D) 1-25 weight% of inorganic fillers.

(E) 1 to 30% by weight of polyphenylene sulfide resin, and

(F) 15-45 weight% of glass fibers.

The components of the composition are described in more detail as follows.

PCT resin as the component (A) of the present invention is an aromatic polyester resin prepared by esterification or transesterification of a glycol with a difunctional carboxylic acid or its ester, followed by polycondensation reaction of a low molecular weight novel product obtained. Poly (1,4-cyclohexylene dimethylene terephthalate) having a viscosity of 0.4 to 1.1, preferably 0.5 to 0.8. When the intrinsic viscosity is lower than the above range, the same physical properties as the composition in the present invention cannot be expected. When it is higher than the above range, there is a difficulty in processing. PCT resin of the present invention is represented by the following chemical structural formula.

As the above-mentioned glycol, 1, 4-cyclohexanedimethanol is used as a main component, and 1, 4-butanediol, 1, 6-hexanediol, 1, 5-pentanediol, ethylene glycol, or 1, 3-propane Diol and the like may be used at 30 mol% or less, preferably 15 mol% or less of the total glycol component. It is hard to expect high heat resistance if it uses beyond the said range.

As the bifunctional carboxylic acid of the present invention, terephthalic acid or dimethyl terephthalate is used as a main component, dimethyl isophthalate, succinic acid, adipic acid, isophthalic acid, 1, 5-naphthalenedicarboxylic acid, 2, 6-naphthalate, 2, 6-naphthalenedi carboxylic acid, dimethyl 2, 6-naphthalate, or 1, 4-cyclohexanedicarboxylic acid or the like may be used at 30 mol% or less of the total acid component.

PCT resin prepared by the above method may be transparent or opaque under the influence of the crystallization rate, and has a melting point of 260 to 300 ° C.

The amount of the PCT resin is 15 to 55% by weight based on the total resin composition, when less than the above range can not be expected to improve the physical properties, if more than the above range there is a risk of discoloration.

Flame retardant of component (B) of the present invention is ethylenebis-tetrabromophthalimide (bromine content of 40 to 80%, more specifically 60 to 70% suitable, melting point 300 ℃ or more Preferably, 400 degreeC or more is 600 or more molecular weight, Preferably 900 or more are suitable. If the bromine content is too small, it is difficult to function as a flame retardant, and in too many bromines there is a decrease in physical properties due to the flame retardant. If the flame retardant melting point is low, there is a possibility of expansion and discoloration due to the microwave and heater of the microwave oven. If the molecular weight is small, there is a possibility of precipitation on the surface of the molded article. The amount used is 5-20% by weight. As the amount of the flame retardant is small, discoloration and swelling tend to increase, and when more than the above range, physical properties may decrease.

As the flame retardant adjuvant which is the component (C) of the present invention, antimony trioxide (Sb ₂ O ₃ ) or zinc borate is used alone or in a mixed state. The amount of flame retardant aid is 1 to 10% by weight. Antimony trioxide is used to increase the flame retardant effect by reacting with bromine-containing flame retardants. In case of using more than 5% by weight, the flame retardancy is increased, but the weld line strength is decreased, so an appropriate amount is required.

As the inorganic filler as the component (D) of the present invention, 1 to 25% by weight of mica, talc, barium sulfate, calcium carbonate, wollastonite, kaolin, and whisker are used. Inorganic fillers work synergistically with flame retardants to prevent discoloration and swelling.

The polyphenylene sulfide resin (E) component of the present invention may be prepared by the reaction of dichlorobenzene (p-dichlorobenzen), sulfur (sulphur) and sodium carbonate (Na ₂ CO ₃ ) or by dichlorobenzene (p-dichlorobenzen) and sodium sulfide. It is produced by the reaction of a pipe (Na ₂ S). The glass transition temperature is 193 ~ 204 ℃, the melting point is about 285 ℃ and it is a high crystalline plastic. It is excellent in heat resistance and mechanical properties and crosslinking phenomenon occurs when it receives heat. When used in combination with PCT resin, it improves the heat resistance of PCT. The use amount is 1-30 weight%.

As (F) component of this invention, 15-45 weight% of glass fibers are used. The length of glass fiber is 2-8 mm, Preferably it is 3-5 mm. Thickness is 7-15 micrometers, Preferably it is 10-13 micrometers. Glass fibers may have various shapes such as spheres, mats, filaments, and long fibers, depending on the application. The smaller the thickness of the glass fiber, the better the physical properties. As the content of glass fiber increases, the strength in the weld decreases, so an appropriate content should be selected.

In addition to the components (A) to (F), anti-dripping agents, antioxidants, and heat stabilizers can be used.

Anti-dripping agent is an additive that prevents plastic from melting and separating when flame is attached to the plastic. It also helps flame retardant effect. Polytetrafluoroethylene is used as an anti-dripping agent, and the addition amount is 0.03 to 5 weight%. If the amount is less than the above range, there is little effect, and if it is large, the flow of resin is badly affected.

In addition, the use of antioxidants and heat stabilizers can help the heat resistance of the PCT resin. Lubricants, coloring agents and the like can also be added.

The composition of this invention can be obtained by melt-processing said each component. The temperature of melt processing is 280-320 degreeC, and it can carry out by a single screw or twin screw extruder.

The present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited only to the following examples.

EXAMPLE

The physical properties of the PCT prepared in Examples and Comparative Examples and the resin composition comprising the same were measured under the following conditions and methods.

1) Tensile strength: measured by ASTM D 638 (unit: kg / cm ² )

2) Flexural strength: measured by ASTM D 790 (unit: kg / cm ² )

3) Flexural modulus: measured by ASTM D 790 (unit: kg / cm ² )

4) Heat deflection temperature: measured at 18.6kg / cm ² load according to ASTM D 648 (unit: ℃)

5) Flame retardant: Flame retardant evaluation by UL 94.

6) Izod impact strength: measured at room temperature 1/8 inch, according to ASTM D 256 (unit: kg. Cm / cm)

7) No load test: A rotating ring was manufactured and a driving test was conducted for 100 minutes in a microwave oven (Model: MA-972MW, LG Electronics).

Production Example (PCT Resin Preparation)

2910 g of dimethyl terephthalate, 1,4-cyclohexanedimethanol (trans / cis mixing ratio = 70/30), and 3456 g of tetrabutyl titanate were added to the reactor, and the temperature was raised to 270 ° C. at normal pressure to complete the transesterification reaction. It was. The product was transferred to a polycondensation reactor and 1.5 g of tetrabutyl titanate was added, followed by bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol 5.7 g of diphosphite, stabilizer, and Iganox 1010 (Shiba). Gaigi Co., Ltd.) After adding 5.7 g, the reaction mixture was gradually increased to 305 ° C. while maintaining a vacuum degree of 0.3 Torr or less to proceed the condensation reaction for 100 minutes. Nitrogen was injected to break up the vacuum, and the polymer was ejected and cooled to obtain PCT. At this time, intrinsic viscosity was 0.75 and melting temperature was 289 degreeC.

Example 1

25% by weight of PCT resin prepared in Preparation Example 1, 15% by weight of ethylene bis-tetrabromophthalimide as a flame retardant, 5% by weight of antimony trioxide as a flame retardant, polyphenylene sulfide resin (SUNTRA SUNG INDUSTRY CO., LTD.) -500) 5% by weight, mica 20% by weight, 30% by weight of glass fibers (LOC-492, LG Owens Corning Co., Ltd.) were mixed and extruded to prepare a mouth (or pellet). The extruder used WP 40Φ with a resin temperature of 307 ° C. The chips thus prepared were dried at 100 ° C. for 5 hours, and then the specimens for physical properties were manufactured with an injection capacity of 75 tons. The fabricated specimens were allowed to stand at 23 ° C. for 24 hours and evaluated by physical properties, flame retardancy, and no load test in a microwave oven according to ASTM and UL 94 methods.

[Examples 2 to 5]

As described in Table 1, except that the content of mica, the inorganic filler, and the inorganic filler were changed to talc, the same method as in Example 1 was performed, and the results are shown in Table 3.

[Comparative Examples 1-7]

It was carried out in the same manner as in Example 1 with the composition shown in Table 2 to evaluate the physical properties according to the type of flame retardant, the results are shown in Table 4.

As can be seen in the above examples, the poly (1,4- of the present invention to which a synergistic combination of ethylenenis-tetrabromphthalimide flame retardant, polyphenylenesulfide resin and inorganic filler is added Cyclohexylene dimethylene terephthalate) resin composition is significantly improved in heat resistance and microwave resistance, there is no deformation and discoloration when used in the rotary ring of the microwave oven and excellent weld line properties.

Claims (12)

(A) 15 to 55% by weight of poly (1,4-cyclohexylenedimethylene terephthalate) resin, (B) 5 to 20% by weight of flame retardant, (C) 1 to 10% by weight of flame retardant aid, (D) inorganic filler Poly (1,4-cyclohexylenedimethylene terephthalate) resin composition containing 1 to 25% by weight, (E) 1 to 30% by weight of polyphenylene sulfide resin, and 15 to 45% by weight of (F) glass fiber . The poly (1,4-cyclohexylenedimethylene terephthalate) resin of the component (A) is obtained by esterification or transesterification using a glycol and a bifunctional carboxylic acid or its ester as a raw material. An aromatic polyester resin prepared by the polycondensation reaction of a molecular weight product, wherein the composition is poly (1,4-cyclohexylenedimethylene terephthalate) having an intrinsic viscosity of 0.4 to 1.1. The composition of claim 2, wherein the glycol comprises 1,4-cyclohexanedimethanol as a main component. The glycol according to claim 2 or 3, wherein the glycol is one or more selected from the group consisting of 1, 4-butanediol, 1, 6-hexanediol, 1, 5-pentanediol, ethylene glycol, and 1, 3-propanediol. The component is used in an amount of up to 30 mole% of the total glycol component. The composition according to claim 2, wherein the difunctional carboxylic acid is used as a main component of terephthalic acid or dimethyl terephthalate. The difunctional carboxylic acid according to claim 2 or 5, wherein the difunctional carboxylic acid is dimethylisophthalate, isophthalic acid, succinic acid, adipic acid, 1, 5-naphthalenedicarboxylic acid, 2, 6-naphthalate, 2, 6-naphthalenedica At least one component selected from the group consisting of carboxylic acid, dimethyl 2, 6-naphthalate, and 1,4-cyclohexanedicarboxylic acid is used in an amount of up to 30 mole% of the total acid component. . The resin composition according to claim 1 or 2, wherein the flame retardant of component (B) is ethylenebis-tetra bromophthalimide. The resin composition according to claim 1 or 2, wherein the flame retardant adjuvant of component (C) is used in the form of singly or mixed antimony trioxide (Sb ₂ O ₃ ) or zinc borate. The composition according to claim 1 or 2, wherein the inorganic filler of component (D) is at least one selected from the group consisting of mica, talc, barium sulfate, calcium carbonate, ulastonite, kaolin, and whiskers. The polyphenylene sulfide resin according to claim 1 or 2, wherein the polyphenylene sulfide resin of component (E) is prepared by the reaction of p-dichlorobenzen, sulfur and sodium carbonate (Na ₂ CO ₃ ) or dichlorobenzene ( p-dichlorobenzen) and sodium sulfide (Na ₂ S), characterized in that the composition prepared by the reaction. The composition according to claim 1 or 2, wherein the glass fibers of component (F) are glass fibers in the form of spheres, mats, filaments, and long fibers. The composition of claim 1 or 2, further comprising polytetrafluoroethylene, which is an antidripping agent.