KR102371020B1 - conductive polyamide resin composition, method for manufacturing same, and molded article comprising same - Google Patents

Abstract

The present invention relates to a conductive polyamide resin composition, a method for manufacturing the same, and a molded article, and more particularly, the present invention relates to a molded article having uniform conductivity by masterbatching carbon nanotubes and polycarboxylate included in the polyamide resin composition It is characterized by providing

Description

Conductive polyamide resin composition, manufacturing method thereof, and molded article

The present invention relates to a conductive polyamide resin composition, a method for manufacturing the same, and a molded article, and more particularly, the present invention relates to a molded article having uniform conductivity by masterbatching carbon nanotubes and polycarboxylate included in the polyamide resin composition It is characterized by providing

Engineering plastics used as automobile fuel filter parts require high rigidity, thermal stability and uniform electrical conductivity.

A common method of imparting high rigidity and electrical conductivity to engineering plastics at the same time is to add carbon fiber (CF). When carbon fiber, which is a conductive fiber, is added to engineering plastics, the surface resistivity is lowered, and the desired level of electrical properties can be secured, and the rigidity is also increased. However, due to the nature of the fibers, there are fibers having different orientations and lengths due to forces generated during processing such as extrusion and injection. This causes a problem of non-uniformity in conductivity of the final product.

A method of adding carbon nanotubes (CNT) was reviewed to compensate for the non-uniformity of conductivity caused by the diversity of orientation and length of carbon fibers, but carbon nanotubes have a very low specific gravity, so a small amount is used in the extrusion process. There are problems that are difficult to put in. In addition, carbon nanotubes have the property of easily forming an agglomerated structure by the Van der Waals force on the surface. Due to these characteristics, carbon nanotubes are not evenly dispersed in engineering plastics, and it is difficult to obtain uniform conductivity as described.

Conventionally, a method of applying a water reducing agent as an additive for preventing aggregation of the carbon nanotubes is being considered, but most of the water reducing agents thermally decompose at the engineering plastic processing temperature, resulting in the generation of a large amount of gas, thereby lowering the mechanical rigidity of the final product. , problems such as a decrease in surface properties are occurring.

Korean Patent Laid-Open No. 10-2019-0078735 relates to a conductive polyamide resin composition, a method for manufacturing the same, and a molded article, wherein an aromatic vinyl compound-vinyl cyan compound copolymer, a vinyl cyanide compound-conjugated diene compound-aromatic vinyl to a polyamide resin Compound copolymer, N-phenylmaleimide compound-aromatic vinyl compound copolymer, carbon fiber, polyether amide-based copolymer and flow improver are blended within a specific content range to have high mechanical properties and electrical conductivity while maintaining appearance quality and moldability Although the reinforced conductive polyamide resin composition is provided, a method for solving the problem of non-uniformity in conductivity of a finally manufactured molded article is not provided.

Korean Patent Publication No. 10-2019-0078735

ADVANTAGE OF THE INVENTION According to this invention, it is an object to provide the molded article which has uniform electroconductivity using a polyamide resin composition.

According to the present invention, an object of the present invention is to provide a method for solving a problem in which mechanical rigidity and surface properties of a molded article are deteriorated due to gas generated during the process.

The object of the present invention is not limited to the object mentioned above. The object of the present invention will become clearer from the following description, and will be realized by means and combinations thereof described in the claims.

According to the present invention, the base resin; glass fiber; carbon fiber; A first masterbatch containing carbon nanotubes; a second masterbatch comprising a water reducing agent comprising polycarboxylate; and additives; It provides a polyamide resin composition comprising a.

The base resin may have a relative viscosity (R.V) of 2.0 to 2.7.

The glass fiber may have a diameter of 9 to 14 μm and a length of 4 to 8 mm.

The first masterbatch may include a polyamide resin and carbon nanotubes.

The first masterbatch may include 88 wt% to 92 wt% of a polyamide resin, and 8 wt% to 12 wt% of carbon nanotubes.

The second masterbatch may include a polyamide resin and a water reducing agent.

The second masterbatch may include 92 wt% to 97 wt% of a polyamide resin, and 3 wt% to 8 wt% of a water reducing agent.

The first masterbatch may include 0.1 to 1.0 parts by weight of the additive based on 100 parts by weight of the polyamide resin, and the second masterbatch may include 0.1 to 1.0 parts by weight of the additive based on 100 parts by weight of the second masterbatch .

The additive may include at least one of a lubricant and an antioxidant.

The polyamide resin composition is 30% to 69.5% by weight of the base resin, 15% to 25% by weight of glass fiber, 5% to 15% by weight of carbon fiber, 5% to 15% by weight of the first masterbatch, and the second It may include 5 wt% to 15 wt% of the masterbatch and 0.2 wt% to 2.0 wt% of the additive.

According to the present invention, a masterbatch preparation step of preparing a first masterbatch containing carbon nanotubes and a second masterbatch containing a water reducing agent containing polycarboxylate; kneading the first masterbatch and the second masterbatch together with a base resin, glass fiber, carbon fiber and additives; and an injection step; It provides a method for producing a polyamide resin composition comprising:

The first masterbatch may be prepared by introducing and kneading a polyamide resin and carbon nanotubes to a first extruder.

The second masterbatch may be prepared by introducing and kneading a polyamide resin and a water reducing agent to a second extruder, and the kneading may be performed while removing the generated gas.

According to the present invention, there is provided a molded article, characterized in that produced by including the polyamide resin composition.

According to the present invention, it is possible to provide a molded article having uniform conductivity by using the polyamide resin composition.

According to the present invention, it is possible to provide a method for solving a problem in which mechanical rigidity and surface properties of a molded article are deteriorated due to gas generated during the process.

The effects of the present invention are not limited to the above-mentioned effects. It should be understood that the effects of the present invention include all effects that can be inferred from the following description.

1 is a flowchart showing a method for preparing a polyamide resin composition of the present invention.

The above objects, other objects, features and advantages of the present invention will be easily understood through the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In this specification, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other features It is to be understood that it does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof. Also, when a part of a layer, film, region, plate, etc. is said to be “on” another part, it includes not only the case where the other part is “directly on” but also the case where there is another part in between. Conversely, when a part of a layer, film, region, plate, etc. is said to be “under” another part, this includes not only cases where it is “directly under” another part, but also a case where another part is in the middle.

Unless otherwise specified, all numbers, values, and/or expressions expressing quantities of ingredients, reaction conditions, polymer compositions and formulations used herein, contain all numbers, values and/or expressions in which such numbers essentially occur in obtaining such values, among others. Since they are approximations reflecting various uncertainties in the measurement, it should be understood as being modified by the term "about" in all cases. Also, where the present disclosure discloses numerical ranges, such ranges are continuous and inclusive of all values from the minimum to the maximum inclusive of the range, unless otherwise indicated. Furthermore, when such ranges refer to integers, all integers inclusive from the minimum to the maximum inclusive are included, unless otherwise indicated.

In this specification, when a range is described for a variable, the variable will be understood to include all values within the stated range including the stated endpoints of the range. For example, a range of “5 to 10” includes the values of 5, 6, 7, 8, 9, and 10, as well as any subranges such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc. It will be understood to include any value between integers that are appropriate for the scope of the recited range, such as 5.5, 6.5, 7.5, 5.5 to 8.5 and 6.5 to 9, and the like. Also for example, ranges from "10% to 30%" include values of 10%, 11%, 12%, 13%, etc. and all integers up to and including 30%, as well as 10% to 15%, 12% to It will be understood to include any subranges such as 18%, 20% to 30%, etc., as well as any value between reasonable integers within the scope of the recited ranges, such as 10.5%, 15.5%, 25.5%, and the like.

The present invention relates to a polyamide resin composition having conductivity, a method for preparing the polyamide resin composition, and a molded article comprising the polyamide resin composition and having uniform conductivity.

Hereinafter, each component included in the polyamide resin composition of the present invention will be described, and a method for manufacturing the polyamide resin composition of the present invention will be described with reference to the flowchart of FIG. 1 .

polyamide resin composition

The polyamide resin composition of the present invention is characterized in that it includes a first masterbatch including a base resin, glass fiber, carbon fiber, and carbon nanotubes, a second masterbatch including a water reducing agent including polycarboxylate, and additives am.

base resin

The base resin of the present invention preferably contains a polyamide resin.

The base resin preferably comprises polyamide 6 having a relative viscosity (R.V) value of 2.0 to 2.7.

The polyamide resin composition of the present invention contains 30% to 69.5% by weight of the base resin.

fiberglass

The glass fiber of the present invention preferably has a diameter of 9 μm to 14 μm and a length of 4 to 8 mm. At this time, when the size or length of the diameter of the glass fiber is smaller than the above range, the reinforcing effect may be insufficient and the physical properties may be deteriorated, and if the size or length of the diameter exceeds the above range, problems in mixing and workability may occur.

The polyamide resin composition of the present invention contains 15% to 25% by weight of glass fibers.

carbon fiber

The polyamide resin composition of the present invention basically includes carbon fibers in order to impart electrical conductivity and rigidity to the molded article.

The polyamide resin composition of the present invention contains 5% to 15% by weight of carbon fibers.

first masterbatch

The polyamide resin composition of the present invention includes a first masterbatch, and the first masterbatch includes a polyamide resin and carbon nanotubes.

The carbon nanotubes are masterbatched together with the polyamide resin, so that they can be easily introduced into the extruder and the dispersibility can be improved in the polyamide resin composition.

More specifically, the first masterbatch includes 88 wt% to 92 wt% of a polyamide resin and 8 wt% to 12 wt% of carbon nanotubes.

The first masterbatch may further include an additive including at least one of an antioxidant and a lubricant, wherein the additive is 0.1 to 1.0 parts by weight based on 100 parts by weight of the polyamide resin included in the first masterbatch. weight is included.

2nd masterbatch

The polyamide resin composition of the present invention includes a second masterbatch, and the second masterbatch includes a polyamide resin and a water reducing agent.

The water reducing agent preferably comprises a polycarboxylate.

The water reducing agent containing the polycarboxylate is masterbatched together with the polyamide resin, so that the gas generated by itself during kneading can be removed in advance, thereby making it possible to manufacture a molded article without deterioration of mechanical rigidity and surface properties. .

The second masterbatch more specifically includes 92 wt% to 97 wt% of a polyamide resin and 3 wt% to 8 wt% of a water reducing agent.

The second masterbatch may further include an additive including at least one of an antioxidant and a lubricant, wherein the additive is 0.1 to 1.0 parts by weight based on 100 parts by weight of the polyamide resin contained in the second masterbatch. weight is included.

additive

The additive of the present invention includes at least one of a lubricant and an antioxidant.

The polyamide resin composition of the present invention contains 0.2 wt% to 2.0 wt% of an additive. Specifically, the lubricant may be included in 0.1 wt% to 1.0 wt%, and the antioxidant may be included in 0.1 wt% to 1.0 wt%.

In the present invention, the type of the additive is not particularly limited, and only conventional lubricants and antioxidants are sufficient.

The polyamide resin composition of the present invention is preferably 30% to 69.5% by weight of the base resin, 15% to 25% by weight of glass fiber, 5% to 15% by weight of carbon fiber, 5% to 15% by weight of the first masterbatch %, 5% to 15% by weight of the second masterbatch and 0.2% to 2.0% by weight of additives.

Method for preparing polyamide resin composition

The method for preparing a polyamide resin composition of the present invention includes a masterbatch preparation step of preparing a first masterbatch containing carbon nanotubes and a second masterbatch containing a water reducing agent containing polycarboxylate, the first masterbatch and It is characterized in that it includes the step of kneading the second masterbatch together with the base resin, glass fiber, carbon fiber and additives, and the injection step.

1 is a flow chart for a method for preparing a polyamide resin composition of the present invention is simply shown. With reference to this, I will explain each step by step.

Masterbatch preparation stage

It is a masterbatch preparation step of preparing a first masterbatch containing carbon nanotubes and a second masterbatch containing a water reducing agent containing polycarboxylate.

The first masterbatch and the second masterbatch of the present invention are each independently produced, and the first masterbatch and the second masterbatch are characterized in that they are produced by an extruder.

The first masterbatch is prepared by injecting and kneading polyamide resin and carbon nanotubes in a first extruder, and masterbatching it in the form of pellets.

The first extruder may include any one of a single screw extruder and a continuous twin screw extruder.

The second masterbatch is prepared by injecting and kneading the polyamide resin and water reducing agent in a second extruder, and masterbatching it in the form of pellets.

The second extruder may include any one of a single screw extruder and a continuous twin screw extruder.

The second extruder may preferably include a gas outlet for discharging gas generated by the mixing of the material from the inside to the outside. That is, the kneading of the polyamide resin and the water reducing agent is characterized in that the generated gas is removed through the gas outlet of the second extruder.

kneading step

This is a step of kneading the previously prepared first masterbatch and the second masterbatch together with the base resin, glass fiber, carbon fiber and additives. More specifically, it is a step of kneading the first masterbatch, the second masterbatch, the base resin, glass fiber, carbon fiber and additives for a predetermined time after inputting the extruder.

The extruder may include any one of a single screw extruder and a continuous twin screw extruder.

injection stage

In this step, after sufficiently kneading the first masterbatch, the second masterbatch, the base resin, glass fiber, carbon fiber and additives, it is injected.

It can be masterbatched in the form of pellets by the injection, or can be directly injected into a mold to manufacture a molded article.

molded product

The molded article in the present invention can be manufactured by kneading and injecting a polyamide resin composition comprising a base resin, glass fiber, carbon fiber, first masterbatch, second masterbatch and additives, or base resin, glass fiber, carbon The fiber, the first masterbatch, the second masterbatch, and the masterbatch including the additive may be prepared by melting and mold molding.

Hereinafter, the present invention will be described in more detail through specific examples. However, these examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

Examples 1 to 3 and Comparative Examples 1 to 7

As shown in Table 1 below, polyamide resin compositions were prepared, kneaded using an extruder, and then injected to prepare each specimen.

Example
One Example
2 Example
3 comparative example
One comparative example
2 comparative example
3 comparative example
4 comparative example
5 comparative example
6 comparative example
7 base resin 49.5 54.5 44.5 69.5 68.5 59.5 59 59 68 58.5 GF 20 20 20 20 20 20 20 20 20 20 CF 10 10 10 10 10 10 10 10 10 10 CNT - - - - One - - - One One water-reducing agent 1 - - - - - - 0.5 - 0.5 - water-reducing agent 2 - - - - - - - 0.5 - - MB1 10 10 10 - - 10 10 10 - - MB2 10 5 15 - - - - - - 10 additive 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Base resin - polyamide 6 (relative viscosity 2.0)
GF- Average diameter 10㎛, average length 6㎜
CNT- Carbon nanotube (Kumho Petrochemical, 100T)
Water-reducing agent 1- Polycarboxylate
Water-reducing agent 2- Naphthalene
MB1- Polyamide resin 90wt%/CNT 10wt%
MB2- Polyamide resin 95wt%/Polycarboxylate 5wt%
Participating agent- Lubricant 0.3wt%/Antioxidant 0.2wt%

Experimental Example 1

Tensile strength, elongation at break, flexural strength, flexural modulus, Charpy impact strength, workability, specimen appearance quality, TGA weight reduction rate and Surface resistance was measured and the results are shown in Table 2.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 tensile strength
[MPa] 220 223 215 230 205 217 207 190 198 203 Elongation at break [%] 2.5 2.5 2.3 2.6 2.0 2.4 2.0 1.6 1.8 1.9 Flexural strength [MPa] 3.25 328 320 335 310 320 308 300 302 305 Flexural modulus [MPa] 13,800 13,900 13,500 14,200 13,000 13,300 12,900 12,400 12,700 12,900 Charpy impact strength
[KJ/m ² ] 10.5 10.6 10.0 10.8 10.0 10.3 10.0 9.0 9.5 9.7 Workability Good Good Good Good Good Good Bad Bad Bad Good appearance quality O O O O O O X X X O Weight reduction rate [%] 0.3 0.3 0.4 0.2 0.2 0.2 1.2 1.2 1.3 0.3 Surface resistance [Ω] 10 ⁴
~10 ⁵ 10 ⁴
~10 ⁵ 10 ⁴
~10 ⁵ 10 ⁵
~10 ¹² 10 ³
~10 ¹² 10 ⁵
~10 ¹² 10 ⁵
~10 ¹² 10 ⁴
~10 ⁸ 10 ³
~10 ⁸ 10 ⁴
~10 ⁵ Tensile strength - measured according to ISO 527
Elongation at break- Measured according to ISO527
Flexural strength- Measured according to ISO 178
Charpy impact strength - measured according to ISO 179/1eA
Workability (Bad)- Difficulty in continuous work due to the occurrence of single yarn phenomenon due to foaming
Appearance quality- Visually evaluate the appearance using a round specimen with a diameter of 10 cm.
Weight loss rate- TGA weight loss rate (N2, 270℃, 1hr)
Surface resistance- Measured according to IEC60093

Claims (14)

base resin;
glass fiber;
carbon fiber;
A first masterbatch containing carbon nanotubes;
a second masterbatch comprising a water reducing agent comprising polycarboxylate; and
additive; A polyamide resin composition comprising a. The method of claim 1,
The polyamide resin composition of the base resin will have a relative viscosity (RV) value of 2.0 to 2.7. The method of claim 1,
The glass fibers have a diameter of 9 to 14 μm and a length of 4 to 8 mm of the polyamide resin composition. The method of claim 1,
The first masterbatch is a polyamide resin composition comprising a polyamide resin and carbon nanotubes. 5. The method of claim 4,
The first masterbatch is a polyamide resin composition comprising 88 wt% to 92 wt% of a polyamide resin, and 8 wt% to 12 wt% of carbon nanotubes. The method of claim 1,
The second masterbatch is a polyamide resin composition comprising a polyamide resin and a water reducing agent. 7. The method of claim 6,
The second masterbatch is a polyamide resin composition comprising 92 wt% to 97 wt% of a polyamide resin, and 3 wt% to 8 wt% of a water reducing agent. 5. The method of claim 4,
The first masterbatch contains 0.1 to 1.0 parts by weight of additives based on 100 parts by weight of the polyamide resin,
The second masterbatch is a polyamide resin composition comprising 0.1 to 1.0 parts by weight of an additive based on 100 parts by weight of the second masterbatch. The method of claim 1,
The additive is a polyamide resin composition comprising at least one of a lubricant and an antioxidant. The method of claim 1,
The polyamide resin composition is 30% to 69.5% by weight of the base resin, 15% to 25% by weight of glass fiber, 5% to 15% by weight of carbon fiber, 5% to 15% by weight of the first masterbatch, and the second A polyamide resin composition comprising 5 wt% to 15 wt% of a masterbatch and 0.2 wt% to 2.0 wt% of an additive. A masterbatch preparation step of preparing a first masterbatch containing carbon nanotubes and a second masterbatch containing a water reducing agent containing polycarboxylate;
kneading the first masterbatch and the second masterbatch together with a base resin, glass fiber, carbon fiber and additives; and
injection step; A method for producing a polyamide resin composition comprising: 12. The method of claim 11,
The first masterbatch is a method for producing a polyamide resin composition prepared by introducing and kneading a polyamide resin and carbon nanotubes into a first extruder. 12. The method of claim 11,
The second masterbatch is prepared by introducing and kneading a polyamide resin and a water reducing agent to a second extruder,
The kneading is a polyamide resin composition manufacturing method that proceeds while removing the generated gas. A molded article prepared by including the polyamide resin composition according to any one of claims 1 to 10.

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