KR100718908B1 - Conductive polypropylene resin composition and foam prepared by using the same - Google Patents

Abstract

The present invention relates to a conductive polypropylene resin composition and a foam produced using the same. More specifically, the conductive polypropylene resin composition of the present invention is extruded by containing (a) polypropylene resin, (b) polyaniline composite, (c) nickel coated carbon fiber, and (d) modified polypropylene resin. Impact resistance is improved by improving the interfacial adhesion between the resins, and the conductivity is improved by the continuous structure of the nickel-coated carbon fiber and synergy with the polyaniline composite.

Polypropylene * Polyaniline Composite * Nickel Coated Carbon Fiber * Modified Polypropylene * Conductive

Description

Conductive polypropylene resin composition and foam prepared by using the same

The present invention relates to a conductive polypropylene resin composition and a foam produced using the same. More specifically, the conductive polypropylene resin composition of the present invention is extruded by containing (a) polypropylene resin, (b) polyaniline composite, (c) nickel coated carbon fiber, and (d) modified polypropylene resin. Impact resistance is improved by improving the interfacial adhesion between the resins, and the conductivity is improved by the continuous structure of the nickel-coated carbon fiber and synergy with the polyaniline composite.

Plastic materials, in particular polypropylene materials, are widely used for packaging materials through foaming because they have excellent mechanical resistance, tensile strength, flexural strength, chemical resistance, moldability, and low cost. However, plastic materials, including polypropylene, are generally nonconductive insulators, and therefore, the use of conductive materials is essential for use in packaging materials for electrical and electronic products. Due to this conductivity, polypropylene composites are widely used in the precision industry such as transportation of electronic products, especially in the case of transfer trays and packaging materials for accommodating electrical and electronic products such as LCD, and their use is increasing. And the demand for polypropylene composite having excellent conductivity due to the increase in precision is increasing rapidly.

As a method of maintaining such conductivity, polypropylene-polyaniline has recently emerged, and polypropylene-aniline disperses polyaniline, which is a conductive polymer, in a polymer, unlike the method of applying conductive carbon and an antistatic agent after molding a conventional package. It is a technique which can improve electroconductivity. In addition, conventional polymer composites contain inorganic additives in a tens percent percent by weight to improve conductivity, but the use of polypropylene-polyaniline can greatly reduce the amount thereof, and thus the physical properties of the material are also equivalent to those of conventional polypropylene composites. It has the advantage of being kept at a level.

As a technique for imparting conductivity using such polyaniline, Japanese Patent Application Laid-Open No. 7-258409 proposed a polyaniline synthesis method and polypropylene-polyaniline having conductivity, melt processability, and thermal stability, and a basic concept is to synthesize polyaniline having a neutral pH. And 10 wt% of polypropylene to prepare a conductive polypropylene having a surface specific resistance of 10 ⁴ to 10 ⁵ Ω cm. However, when only 10% by weight of polyaniline is included, the use of only a limited number of films is currently attempted due to problems such as sudden drop in conductivity during foaming and kneading with polypropylene.

Therefore, the present inventors have studied to solve the above problems, and when the polyaniline composite material, nickel-coated carbon fiber, modified polypropylene is added and extruded, impact resistance is improved by improving the interfacial adhesion between resins. It was found that a conductive polypropylene resin composition with improved conductivity was produced by the continuous structure of the nickel-coated carbon fiber and the synergy with the polyaniline composite, and completed the present invention.

Accordingly, an object of the present invention is to provide a polypropylene resin composition having improved impact resistance and improved conductivity by improving interfacial adhesion between resins.

In addition, another object of the present invention is to provide a foam produced by extruding the conductive polypropylene resin composition.

In order to achieve the above object, the conductive polypropylene resin composition of the present invention is based on the total weight of the composition

(a) 83 to 94% by weight of polypropylene resin;

(b) 5-10% by weight of polyaniline composites;

(c) 1 to 5% by weight of nickel coated carbon fibers;

(d) 0.1 to 2% by weight of modified polypropylene resin;

It is characterized by containing.

Hereinafter, each component of the conductive polypropylene crab resin composition according to the present invention will be described in more detail.

(a) polypropylene resin

Polypropylene resin used in the present invention has a melt index of 5 ~ 15g / 10min in the form of a powder of 5mm or less, preferably 2mm or less, propylene and ethylene 1 ~ 10 mol% binary copolymer or ethylene 1 ~ 5 mol % And butene-1 1-5 mol% ethylene, butene-1 terpolymer. The polypropylene resin (a) is contained in 83 to 94% by weight based on the total weight of the composition. This is because if the content is less than 83% by weight, problems such as change or decrease in bending strength, impact strength, and the like, which are mechanical properties of the polypropylene, occur, and when it exceeds 94% by weight, the conductivity cannot be maintained.

(b) polyaniline composites

The polyaniline composite used in the present invention is a core material for increasing the conductivity of polypropylene, and has a dark green color containing 10 to 75% by weight of zinc, a density of 1.0 to 1.2 g / cm 3, and a surface specific resistance of 10 to 50 µm. It uses a polymer and can be used in the form of powder or pellets. The polyaniline composite forms a network structure (conductivity pathways) to facilitate the conduction between (a) polypripropylene and (c) nickel coated carbon fibers, and narrows the interface gap between nickel coated carbon fibers and polypropylene The synergistic effect between the carbon fibers and the resulting carbon fibers can increase the conductivity. The polyaniline composite (b) is contained in 5 to 10% by weight based on the total weight of the composition. This is because if the content is less than 5% by weight, there is a problem in that the conductivity improvement effect is insignificant. If the content is more than 10% by weight, the mechanical properties of the polypropylene, such as bending strength and impact strength, are lowered.

(c) nickel coated carbon fiber

Nickel-coated carbon fiber used in the present invention is a carbon fiber of 0.1 to 15mm in diameter and 0.1 to 15mm in length with a nickel content of 1 to 50%. Nickel-coated carbon fibers are effective for improving conductivity and are contained in an amount of 1 to 5% by weight based on the total weight of the composition. This is because if the content is less than 1% by weight, a problem of insignificant conductivity improvement occurs due to a decrease in dispersibility, and if it exceeds 5% by weight, surface roughening occurs during foaming.

(d) modified polypropylene resin

The modified polypropylene resin used in the present invention is a compatibilizer used to increase the compatibility of (a) polypropylene and (b) polyaniline composites, and is a reactor reactive with nickel-coated carbon fibers at the main or end of the polypropylene. Is a modified polypropylene to which is attached, and as the reactor used, maleic acid, maleic anhydride, carboxylic acid, hydroxyl group and the like can be used. The modified polypropylene uses a weight average molecular weight (Mw) is in the range of 10,000 to 300,000, the form can be used as a powder or pellets. The reactor attached to the modified polypropylene is preferably contained 0.1 to 5% by weight relative to the modified polypropylene. In addition, the (d) modified polypropylene resin is contained in an amount of 0.1 to 2% by weight based on the total weight of the composition, which if the content is less than 0.1% by weight, there is a problem that can not maintain a constant interfacial adhesion due to dispersibility problems This is because, when the content exceeds 2% by weight, the conductivity is rather lowered.

The conductive polypropylene resin composition of the present invention may include additives common to the above components (a) to (d), for example, antioxidants, UV inhibitors, antistatic agents, slip agents, colorants, and the like.

The conductive polypropylene resin composition of the present invention is sufficiently mixed for 1 to 4 minutes at 500 rpm in a Henschel mixer and 1 to 4 minutes at 1,500 rpm in a normal temperature nitrogen atmosphere, and then the processing temperature is 160 to It can be manufactured using a single screw extruder, a multi screw extruder, a kneader or a Benbury mixer, etc. which have L / D of 20 or more at 200 degreeC, Preferably 180-220 degreeC.

It is made into mini pellets again, and water, surfactants and carbon dioxide are added to a nitrogen atmosphere reactor, heated to near the melting point while being pressurized, and then discharged through a nozzle to form a bead foam. The bead foam is maintained for 2 to 3 hours in an air atmosphere of 2-3 atmospheres, and then, the bead foam is placed in a mold mold at room temperature and atmospheric pressure atmosphere and fused with steam to form a foam.

Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, this invention is not limited only to these examples.

Example 1

(a) 88.5 wt% of a terpolymer of propylene with a melt index of 8 g / 10 min and 3 mol% of ethylene, and 3 mol% of butene-1, and 38.5% of a propylene-ethylene-butene-1, and (b) the polyaniline composite component 9% by weight of pellet type panipol's CXM containing 75% zinc, (c) 2% by weight of nickel-coated carbon fiber having a diameter of 7 µm and 6 mm in length, and (d) 5% by weight of maleic anhydride as a compatibilizer. 0.5% by weight of modified polypropylene having a weight average molecular weight of 150,000 grafted thereto was mixed. The final composition thus mixed is sufficiently mixed in a Henschel mixer for 1 minute at 500 rpm and 1 minute at 1,500 rpm for 2 minutes under nitrogen atmosphere, and then subjected to L / D 35 at 180-220 ° C. and 300 rpm. A conductive polypropylene resin composition was prepared using a phosphorus coaxial twin screw extruder.

Example 2

The same material as used in Example 1 was used except that (a) 86.5 wt%, (b) 9 wt%, (c) 4 wt%, and (d) 0.5 wt% were used. It was prepared by the method.

Comparative Example 1

In the manufacturing method of Example 1, using the component (c) and (d), 90% by weight of the component (a), 10% by weight of the component (b) was prepared in the same manner as in Example 1 It was.

Comparative Example 2

In the manufacturing method of Example 1, without using (b) component (a) component 97.5% by weight, (c) component 2% by weight, (d) component using 0.5% by weight of Example 1 In the same manner, a conductive polypropylene resin composition was prepared.

Comparative Example 3

Conductive polypropylene-based resin composition in the same manner as in Example 1 using (d) component 98% by weight, (c) component 2% by weight in the manufacturing method of Comparative Example 2 Was prepared.

[Test Example]

The surface resistance of the conductive polypropylene resin composition prepared in Examples 1 to 2 and Comparative Examples 1 to 3 was measured by using a surface resistance meter after making a plate having a width of 12 cm. The results are shown in Table 4 below.

(a) polypropylene (b) polyaniline composites (c) nickel coated carbon fiber (d) modified polyflopropylene Surface resistance (Ω㎝) Surface Resistance during Foaming (Ω㎝) Example 1 88.5 9 2 0.5 10 ⁴ to 10 ⁵ 10 ⁸ to 10 ⁹ Example 2 86.5 9 4 0.5 10 ⁴ to 10 ⁵ 10 ⁷ to 10 ⁸ Comparative Example 1 90.0 10 - - 10 ⁸ to 10 ⁹ 10 ¹³ to 10 ¹⁴ Comparative Example 2 97.5 - 2 0.5 10 ⁷ to 10 ⁸ 10 ¹⁴⁺ Comparative Example 3 98.0 - 2 - 10 ⁷ to 10 ⁸ 10 ¹⁴⁺

As described above, the conductive polypropylene resin composition according to the present invention improves impact resistance by improving interfacial adhesion between resins during extrusion by adding a polyaniline composite material, nickel-coated carbon fiber, and modified polypropylene to the polypropylene resin. And nickel-coated carbon fiber's continuous structure and synergy with polyaniline composite material improves conductivity, so that it can continuously have the conductivity required in the precision industry field such as transportation of electronic products. In this case, it is possible to prevent damage to home appliances due to deterioration of conductivity due to friction generated during transportation and coating powder such as carbon.

Claims (6)

(A) 83 to 93% by weight, based on the total weight of the composition; (b) 5-10% by weight of polyaniline composites; (c) 1 to 5% by weight of nickel coated carbon fibers; And (d) 0.1 to 2% by weight of modified polypropylene resin; Conductive polypropylene-based resin composition comprising a. The polypropylene resin of claim 1, wherein the polypropylene resin (a) has a melt index of 5 to 15 g / 10 min, 1 to 10 mol% of propylene and 1 to 10 mol% of ethylene or 1 to 5 mol% of ethylene and 1 to 5 mol of butene-1. A conductive polypropylene resin composition, characterized in that it is a terpolymer of% ethylene and butene-1. The method according to claim 1, wherein the polyaniline composite (b) comprises 10 to 75% by weight of zinc and has a density of 1.0 to 1.2 g / cm 3 and a surface specific resistance of 10 to 50 μm cm, characterized in that in the form of powder or pellets. Conductive polypropylene resin composition. [Claim 2] The conductive polypropylene resin according to claim 1, wherein the (c) nickel coated carbon fiber has a diameter of 0.1 to 8 µm and a carbon fiber of 0.1 to 15 mm in length, and the nickel content is 1 to 50%. Composition. The method of claim 1, wherein the (d) modified polypropylene resin has a weight average molecular weight (Mw) in the range of 10,000 to 300,000 selected from the maleic acid, maleic anhydride, carboxylic acid, and hydroxyl groups in the main chain or terminal of the polypropylene A conductive polypropylene resin composition, characterized in that the grafted to 0.1 to 5% by weight. Using the conductive polypropylene resin composition of claim 1, water, surfactant, and carbon dioxide are put into a nitrogen atmosphere reactor and heated to near the melting point while being pressurized, followed by instantaneous discharge through a nozzle to form a bead foam. Method of producing a foam, characterized in that after maintaining for 2 to 3 hours in an air atmosphere of atmospheric pressure and then put in a mold in a normal atmospheric pressure atmosphere and fused with steam.