KR930010233B1 - Polyethylene terephthalate resin composition and composite material made therefrom - Google Patents

Abstract

A polyethylene terephthalate resin composition is prepared by admixing 0.5-20 wt. pts. of the fibrilized full aromatic polyamide pulp-phase single fiber of 0.1-0.5 mm length, 0.001-0.01 mm diameter, and where the ratio of the length to the diameter is more than 100, and 4-15 m2/g of the surface area in 100 wt. pts. of the polyethylene terephthalate resin. The composite material of polyethylene terephthalate resin reinforced with the full aromatic polyamide pulp-phase single fiber is prepd. by the comon method to a sheet or shaped product, and it has more than 12 kg/mm2 of the tensile strength, more than 500 kg/mm2 of the winding elasticity, more than 5 kg cm/m of the shear strees and more than 180 deg.C of the heat deforming temp..

Description

Polyethylene terephthalate resin composition and composite material prepared therefrom

The present invention relates to a polyethylene terephthalate resin composition and a composite material prepared therefrom. In particular, the polyethylene terephthalate resin is reinforced with a wholly aromatic polyamide pulp-like short fiber to improve strength and heat deformation temperature when used as a composite material. It relates to a terephthalate resin composition and a composite material prepared therefrom.

In general, polyethylene terephthalate, a thermoplastic resin represented by polyester, has excellent physical properties and is widely used in textiles, films, bottled products, and composite materials for enflavor. Among them, especially heat resistance, chemical resistance, electrical properties, and durability. This excellent injection molding polyethylene terephthalate is suitable for switches, relays, connectors, outlet cases, trans buttons, motor housings, lighting holders and irons. It is widely used in electronic parts, motor parts, regulated cases, auto parts such as audio and valves, and industrial parts such as office machine housings and lighter cases.

Meanwhile, fibers, films or pulp-like short fibers made of wholly aromatic polyamides are not only light, but also have high strength and high elasticity, and also have heat resistance, abrasion resistance, and electrical insulation, which are inherent in aircraft, automobile industry, building materials, and composites. It is usefully used for special industries such as materials, leisure and sports goods.

Therefore, many studies have been conducted to improve tensile strength, flexural strength, impact strength, and heat deflection temperature by reinforcing glass fiber or carbon fiber to polyethylene terephthalate having excellent characteristics. When manufacturing a composite material by using the melt mixing in a single- or twin-screw extruder, when mixing the glass fiber or carbon fiber with a thermoplastic resin in the mixer due to breakage of the glass fiber or carbon fiber by the screw of the extruder There was a problem that the strength is lower than the glass fiber or carbon fiber in the long fiber state or when reinforced.

Thus, the present invention is to improve the tensile strength, impact strength, flexural strength and heat deformation temperature while solving the conventional problems as described above by reinforcing the mono-aromatic polyamide pulp-like short fibers of polyethylene terephthalate and thus The purpose is to provide a composite material manufactured from.

Hereinafter, the present invention will be described in detail.

The present invention is a resin composition obtained by adding and mixing a wholly aromatic polyamide pulp-like short fibers as a reinforcing agent to polyethylene terephthalate resin, the length is 0.1 to 0.5mm, the diameter is 0.001 to 0.01mm, the ratio of the length to the diameter Polyethylene characterized in that the fibrillated wholly aromatic polyamide pulsed short fibers having a surface area of 4 to 15 m ² / g or more by addition to 0.5 to 20 parts by weight based on 100 parts by weight of polyethylene terephthalate resin. It is a terephthalate resin composition.

In addition, the present invention is characterized in that the tensile strength of 12kg / mm 2 or more, the flexural modulus of 500kg / mm 2 or more, the impact strength of 5kgcm / cm or more, the heat deformation temperature of 180 ℃ or more from the above-described composition prepared in a sheet form or a molded article in a conventional manner It is a polyethylene terephthalate resin composite material reinforced with a wholly aromatic polyamide pulp-like short fiber.

Referring to the present invention in more detail as follows.

The present invention has a length (L) of about 0.1 to 0.5mm, a diameter (D) of about 0.001 to 0.01mm, the aspect ratio (L / D) of about 100 or more and the surface area of about 4.0 to 15.0 m 2 / g The blended blend of the braylated wholly aromatic polyamide pulp-like short fibers with respect to 100 parts by weight of polyethylene terephthalate resin is about 0.5 to 20 parts by weight, and particularly preferably the wholly aromatic polyamide pulp-like short fibers to polyethylene terephthalate. It is good to add 1-15 weight part. If the content of the wholly aromatic polyamide pulp-like short fibers is less than 0.5 parts by weight, the reinforcing action is mild and effective reinforcing to the desired degree cannot be obtained, while the content of the wholly aromatic polyamide pulp-like short fibers exceeds 20 parts by weight. In addition, the present invention is not only difficult to completely mix with the resin, but also has a problem in the mixing process in the melt mixer.

In addition, the impact strength and the flexural modulus of the resin composition according to the present invention are increased almost linearly with increasing the content of the short fibers on the wholly aromatic polyamide pulp, while the heat deformation temperature and the tensile strength are the wholly aromatic polyamide pulp. The portion of the low aromatic short fiber increased rapidly as the content of the monoaromatic polyamide pulp-like short fiber increased, but the content of the wholly aromatic polyamide pulp-like short fiber was high in the portion of the high aromatic polyamide pulp-like short fiber. As they increase, the increase of these values appears small.

In addition, the composition may be molded by using a compression roller or under shear conditions. In this case, in order to obtain a sheet phase, it is preferable to use a conventional compression roller, and to obtain a molded article, a conventional extruder. Preference is given to using. In general, since polyethylene terephthalate may be deteriorated due to hydrolysis or pyrolysis during molding, when polyethylene terephthalate is melted in the presence of water, a hydrolysis reaction occurs to generate a low molecular weight oligomer or monomer. Will be. Therefore, the water content of the resin supplied at the time of molding must be dried to be 0.01 to 0.02% by weight or less based on the total composition. In addition, since the thermal decomposition occurs when the melting point exceeds 50 ℃, it is preferable to set the temperature in the melt mixer to a low, it is preferable to shorten the residence time in the molten state. Since the crystallization rate of the polyethylene terephthalate is low, the crystallinity is lowered when the temperature of the mold is lowered, so that the temperature of the mold may be set higher, which causes thermal decomposition. Therefore, in order to increase the crystallization rate of polyethylene terephthalate when the temperature of the mold is low, crystallization nucleating agents such as metal oxides, inorganic salts and organic acid salts may be added to the composition according to the present invention.

On the other hand, the mono-aromatic polyamide pulp-like short fibers have a problem that it is difficult to be sprayed unless premixed before being added to the melt mixer because fluffs are likely to occur, and thus preliminary using a mixing device that rotates at high speed before being introduced into the melt mixer. It is preferable to mix, and the premixing step may include one or more mixing steps. The premixed composition may be manufactured into a composite material of a molded article or a sheet-like composite material by a compression roller or by extrusion. In this case, when the sheet is manufactured, the monoaromatic polyamide pulp-like short fibers are arranged in one direction so as to be parallel to the longitudinal direction of the compressed sheet, and in the case of extrusion molding under shear conditions, they are arranged parallel to the extrusion direction of the extruded part. Will be.

The composite material prepared by the above method using the resin composition according to the present invention was found to have a tensile strength of 12kg / ㎜ or more, flexural modulus of 500kg / ㎜ or more, impact strength of 5kg · cm / cm or more, heat deformation temperature of 180 ℃ or more .

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1

High performance of high speed rotation after adding 3 parts by weight of a wholly aromatic polyamide pulp-like short fiber having an average length of 0.5 mm, an average diameter of 0.002 mm, and a surface area of 6 m 2 / g to 100 parts of polyethylene terephthalate resin. Premixed to a mixer to prepare a composition of the composite, which was then melted in a melt mixer and injection molded to produce a wholly aromatic polyamide reinforced composite material. At this time, the cylinder temperature of the melt mixer was 265 ℃, the injection pressure was about 800kg / ㎠, the molding time was 15 seconds while maintaining the temperature of the mold 75 ℃. At this time, the properties of the wholly aromatic polyamide pulp-like short fiber reinforced composite material are shown in Table 1 below.

TABLE 1

Example 2

After adding 8 parts by weight of a wholly aromatic polyamide pulp-like short fiber having an average length of 0.3 mm, an average diameter of 0.001 mm, and a surface area of 9 m 2 / g to 100 parts by weight of polyethylene terephthalate resin, Premixed to a high performance mixer to prepare a composite composition, which was then melted in an melt mixer and injection molded to produce a wholly aromatic polyamide reinforced composite. At this time, the cylinder temperature of the melt mixer was 270 ℃, the injection pressure was about 800kg / ㎠, the molding time was 20 seconds while maintaining the temperature of the mold 78 ℃. The properties of the wholly aromatic polyamide pulp-like short fiber reinforced composite material prepared by this method are shown in Table 2 below.

TABLE 2

Example 3

To 100 parts by weight of polyethylene terephthalate resin, 12 parts by weight of a wholly aromatic polyamide pulp-like short fiber having an average length of 0.5 mm, an average diameter of 0.002 mm, and a surface area of 6 m 2 / g was added to 100 parts by weight of a polyethylene terephthalate resin, followed by high speed rotation. It was premixed in a high performance mixer to prepare a composition of the composite, which was then melted in an melt mixer and injection molded to produce a wholly aromatic polyamide reinforced composite material. At this time, the cylinder temperature of the melt mixer was 265 ℃, the injection pressure was about 800kg / ㎠, the molding time was 10 seconds while maintaining the temperature of the mold 75 ℃. The properties of the wholly aromatic polyamide pulp-like short fiber reinforced composite material prepared by this method are shown in Table 3 below.

TABLE 3

Comparative Example 1

To 100 parts by weight of polyethylene terephthalate resin, 0.3 parts by weight of a wholly aromatic polyamide pulp-like short fiber having an average length of 0.3 mm, an average diameter of 0.001 mm, and a surface area of 9 m 2 / g was added to 100 parts by weight of a polyethylene terephthalate resin, which was then rotated at high speed. Premixed in a high performance mixer to prepare a composite composition, and then melted and injection molded in a melt mixer to prepare a wholly aromatic polyamide reinforced composite material. At this time, the cylinder temperature of the melt mixer was 260 ℃, the injection pressure was about 600kg / ㎠, the molding time was 10 seconds while maintaining the temperature of the mold 75 ℃. The properties of the wholly aromatic polyamide pulp-like short fiber reinforced composite material prepared by this method are shown in Table 4 below.

TABLE 4

Comparative Example 2

High performance mixer which adds 3 parts by weight of a wholly aromatic polyamide pulp-like short fiber having an average length of 3 mm, an average diameter of 0.012 mm and a surface area of 2 m 2 / g to 100 parts by weight of polyethylene terephthalate resin Premixed to prepare a composition of the composite, which was then melted in a melt mixer and injection molded to produce a wholly aromatic polyamide reinforced composite material. At this time, the cylinder temperature of the melt mixer was 265 ℃, the injection pressure was about 800kg / ㎠, the molding time was 10 seconds while maintaining the temperature of the mold 75 ℃. The properties of the wholly aromatic polyamide pulp-like short fiber reinforced composite material prepared by the above method are shown in Table 5 below.

TABLE 5

Comparative Example 3

A composite material was prepared in the same manner as in Example 1, except that 5 parts by weight of cellulose, a pulp-like short fiber, was mixed with 100 parts by weight of polyethylene terephthalate resin. Thus prepared composite material exhibited the characteristics shown in Table 6.

TABLE 6

As can be seen from the above, it can be seen that the composite material prepared from the reinforced resin composition according to the present invention has improved tensile strength, impact strength, flexural modulus, and heat deflection temperature as compared with the composite material prepared from the conventional reinforced resin composition.

Claims (2)

In a resin composition obtained by adding and mixing a wholly aromatic polyamide pulp-like short fiber into a polyethylene terephthalate resin, the length is 0.1 to 0.5 mm, the diameter is 0.001 to 0.01 mm, the ratio of the length to the diameter is 100 or more and the surface area A polyethylene terephthalate resin composition, wherein the fibrillated wholly aromatic polyamide pulp-like short fibers of 4 to 15 m 2 / g are added and mixed with 0.5 to 20 parts by weight based on 100 parts by weight of polyethylene terephthalate resin. Polyethylene terephthalate resin composite material reinforced with monoaromatic polyamide pulp-like short fibers, the length of which is 0.1 to 0.5 mm, the diameter is 0.001 to 0.01 mm, the ratio of the length to the diameter is 100 or more and the surface area is 4 to A fibrillated wholly aromatic polyamide pulp-like short fiber of 15 m 2 / g was added to 0.5 to 20 parts by weight based on 100 parts by weight of polyethylene terephthalate resin to prepare a sheet-like or molded product in a conventional manner. Of polyethylene terephthalate reinforced with mono-aromatic polyamide pulp-like short fibers, characterized in that the tensile strength is more than 12kg / mm2, the flexural modulus is more than 500kg / mm2, the impact strength is more than 5kgcm / cm, the heat deformation temperature is more than 180 ° C. Resin composite materials.