KR20110040489A - Composites high electrical conductivity for inner layer of the automotive fuel tube - Google Patents

Abstract

PURPOSE: A composite for an inner layer of an automotive fuel tube is provided to ensure excellent flexibility, shock resistance, and heat resistance, to stably maintain electric conductivity, and to prevent or reduce dangers caused by fire. CONSTITUTION: A composite for an inner layer of an automotive fuel tube comprises 30~80 weight% of polyamide resin, 5~10 weight% of polyolefin resin, 5~30 weight% of impact reinforcing agent containing a maleic anhydride-grafted ethylene-α-olefin copolymer, 5~30 weight% of conductive filler containing conductive carbon black and carbon nanotubes, 5~30 weight% of softener, and 0.5~10 weight% of reaction control agent.

Description

Composites for automotive fuel tube inner layer with excellent electrical conductivity

The present invention relates to a composite material for automobile fuel tube inner layer comprising a polyamide resin and a polyolefin resin containing a main body, an impact modifier, a conductive filler, a softening agent, a reaction control agent and the like.

Background Art [0002] Conventional automotive fuel tube inner layer materials have been made of PA 12 (nylon 12) which does not impart electrical conductivity as a single material or a material in which conductive carbon black is dispersed. Since the conductive carbon black added to realize the double electrical conductivity is spherical in shape, it is required to add a large amount in order for the particles to be connected to each other to express the electrical conductivity. The currently used material contains more than 20% by weight, more than 25% by weight of conductive carbon black, which has a problem of lowering the impact resistance of the low temperature of the fuel tube, which is a factor of increasing the cost of the material because it is expensive. In addition, even after the conductive carbon black is dispersed in the polyamide resin, even if the dispersion position is slightly changed by the external force, the electrical conductivity is lost, thereby making it difficult to secure stable electrical conductivity. Therefore, securing low-temperature stability, stable electrical conductivity, and competitive price for automobiles are a big issue.

Therefore, the present inventors have tried to solve the problem of the existing automotive fuel tube inner layer material, it was found that by introducing a copolymer of maleic anhydride can solve the low temperature stability problem of the existing fuel tube inner layer material, fuel tube inner layer In order to maintain the optimum electrical conductivity required as a material, carbon black and carbon nanotubes were introduced into the conductive filler, and their optimum amount of use and the optimum composition ratio with other components were found to complete the present invention. That is, the present invention is to provide a composite material for the inner layer of the vehicle fuel tube excellent in electrical conductivity.

The present invention for solving the above problems is polyamide resin; Polyolefin resins; Impact modifiers containing an ethylene-α-olefin copolymer grafted with maleic anhydride; A conductive filler containing conductive carbon black and carbon nanotubes; Softening agents; And a reaction control agent; It is an object to provide a composite material for the inner layer of the vehicle fuel tube, characterized in that it comprises a.

The composite material of the present invention not only has excellent mechanical properties such as flexibility, heat resistance, impact resistance, but also can stably maintain electrical conductivity even after fuel immersion, thereby preventing or reducing the risk of fire caused by sparks. It is also suitable for use as a material for automotive fuel system components, especially for inner layers of automotive fuel tubes.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a composite material for automotive fuel tube inner layer, polyamide resin; Polyolefin resins; Impact modifiers containing an ethylene-α-olefin copolymer grafted with maleic anhydride; A conductive filler containing conductive carbon black and carbon nanotubes; Softening agents; Reaction control agents; It characterized by including the.

When explaining the composition ratio of the composite of the present invention in detail, the present invention is polyamide resin 30 to 80% by weight; 5 to 10 weight percent polyolefin resin; 5 to 30% by weight of the impact modifier; 5 to 30% by weight of the conductive filler, 5 to 30% by weight of a softening agent; 0.5-10% by weight of reaction control agent; Its features include that.

The polyamide resin (Polyamide resin) is the main material of the present invention, nylon 6 (PA 6), nylon 11 (PA 11), nylon 12 (PA 12), nylon 66 (PA 66), homopolyamide (homopolyamide) and One or two or more selected from copolyamides may be used. In addition, the polyamide resin may be used 30 to 80% by weight, more preferably 45 to 65% by weight of the total weight of the composite material of the present invention, wherein when used in less than 30% by weight of the flexibility and compatibility of the material This may be a problem of deterioration, and when used in excess of 80% by weight may reduce the water absorption rate and fuel barrier efficiency (fuel barrier) efficiency is good to use within the above range. The polyamide resin is a polyamide resin having a viscosity of 170 to 190 ml / g (viscosity number) and a polyamide resin having a high viscosity of 210 to 230 ml / g (viscosity number) in a weight ratio of 1: 1 to 2 It is good to obtain melt viscosity for extrusion process.

The polyolefin resin is another main agent of the present invention, which can serve to improve the problems caused by moisture by the hydrophobic polyolefin component, and also provides water resistance, oil resistance, fuel barrier properties, low specific gravity and processability. Play a role. As the polyolefin resin, one or two or more selected from polypropylene resin and polyethylene resin may be used, and the polypropylene resin may use 5 to 10% by weight of the total weight of the composite of the present invention. If it is less than the weight% may have a problem of poor fuel blocking properties, water resistance, and when used in excess of 10% by weight, rather than impact resistance of the composite material may be used within the above range. The polypropylene resin, which is a polyolefin resin, has a melt index (MI) of 0.3 to 10 g / 10 minutes (ASTM D1238, 230 ° C., 2.16 kg), and more preferably 1 to 8 g / 10 minutes (ASTM). D1238, 230 ℃, 2.16kg) is good to use, at this time, if the melt index is less than 0.3 may have a problem of inhibiting compatibility, if the melt index is more than 10 impact strength may be lowered It is preferable to use a melt index within the above range.

The impact modifier serves to improve the impact resistance of the composite of the present invention, and it is preferable to use an ethylene-α-olefin copolymer grafted with maleic anhydride, but the present invention is not limited thereto. It is preferable to use this grafted ethylene-octene copolymer. In this case, when using a copolymer in which maleic anhydride is not grafted, compatibility between the impact modifier and other composite components may be inferior. In addition, the ethylene-α-olefin copolymer is preferably used that is 0.5 to 2.5% by weight of maleic anhydride in the total weight of the copolymer. In this case, when the graft ratio is less than 0.5% by weight, the compatibility of the impact reinforcing material may be lowered, and when the graft ratio exceeds 2.5% by weight, there may be a problem that the viscosity is lowered or the price is increased. . The impact modifier is preferably used 5 to 30% by weight of the total weight of the composite of the present invention, when using less than 5% by weight may be impaired impact properties of the composite, when used in excess of 30% by weight The amount of the components used is relatively reduced, which may cause a problem of deteriorating the overall composite properties.

The conductive filler serves to maintain and maintain electrical conductivity in fuel tube products, using 5 to 30% by weight, more preferably 10 to 25% by weight of the total weight of the composite of the present invention. It is good. At this time, if the amount is less than 5% by weight, sufficient electrical conductivity cannot be imparted to the composite material. If the content is more than 30% by weight, the use of other components is reduced and the impact resistance and flexibility required for the fuel tube are obtained. Since it cannot be used, it is preferable to use within the said range. In addition, the conductive filler is preferably used in the conductive carbon black and the carbon nanotubes in a weight ratio of 1: 0.2 to 2.0, more preferably 1: 0.5 to 1.5, when using less than 1: 0.2 weight ratio , The amount of carbon nanotubes is too small, it may not be possible to see the effect of maintaining the electrical conductivity from external shocks, when used in excess of 1: 2.0 weight ratio, within the above range due to the price increase problem due to the excessive use of carbon nanotubes It is desirable to maintain. In addition, in the present invention, the conductive carbon black serves to prevent explosion or fire of fuel by imparting electrical conductivity to prevent sparking. The conductive carbon black is not particularly limited, but Ketjen black More preferably EC 300J, EC 600 JD It is preferable to use one kind or two or more kinds of Ketjen blacks selected from among them. In addition, the carbon nanotubes serve to maintain the electrical conductivity by connecting the empty space between the spherical conductive carbon black as shown in the schematic diagram of Figure 1, the carbon nanotubes are not particularly limited, the average diameter is It is better to use the one having the property of 10 to 30 nm.

The softening agent is used to add the flexibility of the product to be used as automotive fuel-based components, the softening agent may be used one or two selected from lactam and sulfonamide plasticizers, the amount of the PA It is preferable to use 5 to 30% by weight, more preferably 10 to 25% by weight of the total weight of the / PO / CNT composite. At this time, the use of less than 5% by weight may reduce the flexibility of the product, when used in excess of 30% by weight may decrease the mechanical rigidity is better to use within the above range.

In the present invention, the reaction control agent improves the compatibility between the polyamide resin and the polyolefin resin, and serves to maintain the appropriate viscosity required for extrusion processing of the composite, the compatibilizer is grafted maleic anhydride It is preferable to use polystyrene resin or epoxy resin. In addition, the polystyrene resin grafted maleic anhydride (polystyrene) resin is preferable to use a graft of 5 to 10% by weight of maleic acid in the total weight of the resin for reasons of compatibility and maintain the proper viscosity. It is preferable to use the reaction control agent 0.5 to 10% by weight of the total weight of the composite material of the present invention, when using less than 0.5% by weight, the viscosity required for the extrusion and extrusion process to reduce the compatibility improvement effect due to the reactivity decreases It may not be used, and the use of more than 10% by weight may lower the mechanical strength of the composite material, it is recommended to use within the above range.

Hereinafter, the present invention will be described in more detail based on examples. However, the scope of the present invention is not limited by the following examples.

Example 1

Medium viscosity polyamide resin with a viscosity of 180 ml / g (viscosity number) and high viscosity polyamide resin with a viscosity of 220 ml / g (viscosity number), melt index 4 to 6 g / 10 min (ASTM D1238, 230 ° C, 2.16 kg) polypropylene resin, impact modifier, Ketjen black (conductive carbon black), carbon nanotubes with an average diameter of 10 to 30 nm, the reaction agent, sulfonamide-based softening agent to the weight ratio shown in Table 1 After weighing, it was blended to prepare a composite material for an inner layer of an automobile fuel tube.

Examples 2 to 6 and Comparative Examples 1 to 4

In the same manner as in Example 1, but using the components and component ratios shown in Table 1 to prepare a composite material for the inner layer of the vehicle fuel tube, Examples 2 to 4 and Comparative Examples 1 to 4 were carried out.

division Example Comparative example One 2 3 4 5 6 One 2 3 4 Polyamide resin PA 12 ⁽¹⁾ 18 18 16 17 20 16 20 18 20 20 PA 12 ⁽²⁾ 35 35 35 37 41 35 41 38 41 40 Polyolefin resin Polypropylene Resin ⁽³⁾ 7 7 7 7 6 6 7 7 7 7 Impact modifier MAH-g-EOR ⁽⁴⁾ 8 8 8 8 6 13 8 8 8 8 Conductive filler conductivity
Carbon Black ⁽⁵⁾ 10 10 10 10 10 10 10 15 - 10 Carbon nano
tube PO system ⁽⁶⁾ 5 - 10 - 4 - - - - - PA system ⁽⁷⁾ - 5 - 5 - 4 - - 10 One Reaction Control Agents ⁽⁸⁾ 3 3 3 3 5 5 3 3 3 3 Softener ⁽⁹⁾ 13 13 10 12 7 10 10 10 10 10 (1): nylon 12, midpoint EVONIK (VESTAMID), Ube (UBESTA)
(2): nylon 12, high viscosity EVONIK (VESTAMID), Ube (UBESTA)
(3): Korean oil paintings and polyfuture products with MI = 4 ~ 6
(4): 1.3 wt% maleic anhydride grafted ethylene-octene copolymer, Dupont FUSABOND
(5): EC 300J (brand name) Ketchen black of Mitsubishi Corporation
(6): Polyolefin modificated CNT
(7): Polyamide modificated CNT
(8) Polystyrene resin grafted with 7 wt% maleic anhydride, Nova chem, DYLARK
(9): sulfonamide softener, Proviron

Experimental Example: Property Measurement Experiment

Each of the composites prepared in Examples and Comparative Examples was dry blended for 3 minutes, and then melt kneaded in a conventional manner using a twin screw extruder (diameter 40 mm Φ) set at 250 ° C. to prepare pellets. . Next, the pellet was dried at 90 ° C. for 4 hours, and then a test piece for measuring physical properties was prepared using an injection molding machine set at 250 ° C.

The physical properties of the test pieces were evaluated for five specimens for each test, and then averaged. The results are shown in Table 2 below.

(1) Tensile strength measurement method: Measured according to the method specified in ASTM D 638.

(2) Method for measuring flexural modulus and flexural strength: Measured according to the method specified in ASTM D 790.

(3) Izod impact strength measurement method: measured at room temperature (23 ℃) and low temperature (-40 ℃) according to ASTM D256.

(4) Heat deflection temperature measurement method: measured by a load of 4.6kg according to ASTM D648.

(5) Surface resistance measurement method: measured according to ASTM D257.

The physical properties of the test pieces were evaluated for five specimens for each test, and then averaged. The results are shown in Table 2 below.

As can be seen in Table 2, Comparative Examples 1 to 3 without using the conductive filler or using only one of the two conductive fillers have a surface resistance of 10 ⁶ to 10 ⁷ Ω / sq or more as compared to the embodiment using two conductive fillers together. It can be confirmed that the electrical conductivity is not good because of the high, compared to the amount of the conductive carbon black, the comparative example 4, the amount of the carbon nanotubes used too little was also confirmed that the electrical conductivity is low. In the case of impact strength, the impact strength decreases as the content of the conductive filler increases, and the results are similar in the case of Examples and Comparative Examples.

As confirmed above, the composite material for the inner layer of an automobile fuel tube of the present invention not only has excellent mechanical properties, but also can stably maintain electrical conductivity even after fuel immersion, thereby preventing or reducing the risk of fire caused by sparks. It is suitable for use as a material for fuel system components, especially for inner layers of automotive fuel tubes.

Claims (8)

Polyamide resin 30 to 80 wt%; 5 to 10 weight percent polyolefin resin; 5 to 30% by weight of an impact modifier containing an ethylene-α-olefin copolymer grafted with maleic anhydride; 5 to 30% by weight of a conductive filler containing conductive carbon black and carbon nanotubes; Softening agent 5-30 wt%; And 0.5-10% by weight of reaction control agent; Automobile fuel tube inner layer composite material comprising a. The method of claim 1, wherein the polyamide resin in the vehicle fuel tube, characterized in that it comprises one or more selected from nylon 6, nylon 11, nylon 12, nylon 66, homopolyamide and copolyamide. Floor composites. According to claim 2, wherein the polyamide resin is a polyamide resin of 170 ~ 190 ml / g (viscosity number) and a polyamide resin of 210 ~ 230 ml / g (viscosity number) in a 1: 1 to 2 by weight Automobile fuel tube inner layer composite material, characterized in that used. The composite material for automobile fuel tube inner layer as claimed in claim 1, wherein the polyolefin resin comprises at least one selected from polypropylene resin and polyethylene resin. The composite material for automobile fuel tube inner layer according to claim 4, wherein the polypropylene resin has a melt index (MI) of 0.3 to 10 g / 10 minutes (ASTM D1238, 230 ° C, 2.16 kg). The composite material for automobile fuel tube inner layer according to claim 1, wherein the maleic anhydride-grafted ethylene-α-olefin copolymer is 0.5 to 2.5% by weight of maleic anhydride in the total weight of the copolymer. The composite material of claim 1, wherein the conductive filler comprises conductive carbon black and carbon nanotubes in a weight ratio of 1: 0.2 to 2.0. 8. The composite material for automobile fuel tube inner layer according to claim 1 or 7, wherein the carbon nanotubes have an average diameter of 10 to 30 nm.