KR102205850B1 - Composite resin composition with improved electrical conductivity and preparation method thereof - Google Patents

Abstract

The present invention relates to a composite resin composition which has an excellent effect of improving electrical conductivity even while containing a trace amount of carbon nanotubes. The composite resin composition of the present invention has a unique dispersion shape in which carbon nanotubes are selectively positioned and arranged in a PC resin-SAN resin interface forming a continuous phase in a base resin consisting of a ternary system including a SAN resin having a specific content of acrylonitrile (AN), a PC resin, and a PMMA resin, and a PMMA resin present at the interface, and thus a small amount of carbon nanotubes may be simply added to improve electrical conductivity.

Description

Composite resin composition with improved electrical conductivity and preparation method thereof

The present invention relates to a composite resin composition containing a trace amount of carbon nanotubes and having an excellent electrical conductivity improvement effect.

The conventional technique for improving the electrical conductivity of polymer and carbon nanotube composites attempted so far has been to achieve a condition (percolation) in which nanoparticles dispersed in a continuous phase of a polymer are connected to each other by increasing the content of carbon nanotubes. However, it is not desirable to add a large amount of carbon nanotubes, which are relatively expensive in terms of the cost of manufacturing the resin, and it is a situation that causes difficulties in terms of the processability of resin manufacturing.

To overcome this, the polymer constituting the continuous phase is set as an incompatible two-component blend, and each component forms a continuous phase at the same time through adjustment of their content and viscosity ratio, and the dispersion of carbon nanotubes is connected in a specific phase. Research has been conducted to reduce the amount of carbon nanotubes required to achieve electrical conductivity by induction. In a two-component blend having a mutually continuous phase structure, a peculiar condition for maximizing the linked dispersion of carbon nanotubes is that the carbon nanotubes are selectively arranged at the interface of the two phases. In other words, it means that the conductivity can be improved by densely aligning the carbon nanotubes injected in a certain amount in a very limited spatially. However, the type of blend that satisfies these conditions has a very limited problem. In particular, in the blend of thermoplastic resin and styrene-acrylonitirile (SAN) resin, carbon nanotubes are selectively present on the thermoplastic resin. Since the structure is dominant, there is a problem in that it is difficult to improve the electrical conductivity by placing the carbon nanotubes at the interface between the thermoplastic resin and the SAN resin.

Republic of Korea Patent Publication 10-1082636

The present invention is to solve the above problems, the specific purpose is as follows.

In the present invention, a carbon nanotube is included in a base resin including a styrene-acrylonitirile (SAN) resin, a polycarbonate (PC) resin, and a PMMA resin having a specific content of acrylonitirile (AN). An object of the present invention is to provide a composite resin composition that is specifically positioned at a PC resin-SAN resin interface and a PMMA resin present at the interface to improve electrical conductivity.

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

The composite resin composition according to an embodiment of the present invention includes a polycarbonate (PC) resin, a styrene-acrylonitirile (SAN) resin, and a polymethyl methacrylate (PMMA) resin. Base resin; And carbon nanotubes, and the SAN resin includes 60 to 70% by weight of styrene and 30 to 40% by weight of acrylonitrile (AN).

The carbon nanotubes have a PC resin-SAN resin interface; PMMA resin present at the interface; And it may be dispersed in at least one or more positions selected from the group consisting of a combination thereof.

The base resin may include 40 to 60% by weight of the PC resin, 25 to 40% by weight of the SAN resin, and 5 to 20% by weight of the PMMA resin.

In 100 parts by weight of the base resin, 0.5 to 0.6 parts by weight of the carbon nanotube may be included.

The SAN resin may have a weight average molecular weight of 120,000 to 180,000.

The PMMA resin may have a weight average molecular weight of 60,000 to 90,000.

The carbon nanotubes may be multi-walled carbon nanotubes having an average diameter of 5 to 15 nm and a length of 40 to 70 μm.

A method for preparing a composite resin composition according to an embodiment of the present invention includes a polycarbonate (PC) resin, a styrene-acrylonitirile (SAN) resin, and a polymethyl methacrylate (PMMA) resin. Including the step of kneading a base resin and carbon nanotubes, wherein the SAN resin includes styrene (Styrene) 60 to 70% by weight and acrylonitrile (Acrylonitirile; AN) 30 to 40% by weight.

The method for preparing the composite resin composition may be prepared by kneading at a mixing speed of 180 to 220 RPM and a mixing temperature of 230 to 260°C.

The composite resin composition of the present invention is a PC resin that forms a continuous phase on a base resin composed of a ternary system including a SAN resin, a polycarbonate (PC) resin, and a PMMA resin having a specific content of acrylonitirile (AN). -Since the carbon nanotubes are selectively positioned and arranged in the SAN resin interface and the PMMA resin present at the interface, they have a unique dispersion form, and electrical conductivity can be improved by simply adding a small amount of carbon nanotubes.

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

1A is an image observed with a transmission electron microscope of a composite resin composition prepared according to Examples.
1B is an image obtained by observing a composite resin composition prepared according to the Example and removing a polycarbonate (PC) resin with a scanning electron microscope.
2A is an image of a composite resin composition prepared according to Comparative Example 1 observed with a transmission electron microscope.
2B is an image obtained by observing a composite resin composition prepared according to Comparative Example 1 and removing a PC resin with a scanning electron microscope.

The above objects, other objects, features, and advantages of the present invention will be easily understood through the following preferred embodiments related to 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 contents may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art.

In the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being added.

Unless otherwise specified, all numbers, values, and/or expressions expressing quantities of ingredients, reaction conditions, polymer compositions, and formulations used herein are those that occur in obtaining such values, among other things essentially. Since they are approximations that reflect the various uncertainties of the measurement, it should be understood as being modified in all cases by the term "about". In addition, when numerical ranges are disclosed herein, these ranges are continuous and, unless otherwise indicated, include all values from the minimum value of this range to the maximum value including the maximum value. Furthermore, when this range refers to an integer, all integers from the minimum value to the maximum value including the maximum value are included, unless otherwise indicated.

Composite resin composition

The composite resin composition according to an embodiment of the present invention includes a base resin including a thermoplastic resin, a styrene-acrylonitirile (SAN) resin, and a polymethyl methacrylate (PMMA)-based resin; And carbon nanotubes, preferably polycarbonate (PC) resin, styrene-acrylonitirile (SAN) resin, and polymethyl methacrylate (PMMA) resin. The SAN resin may contain 60 to 70% by weight of styrene and 30 to 40% by weight of acrylonitirile (AN).

The composite resin composition according to the present invention comprises the carbon nanotubes 0.5 to 0.6 in the middle portion of the base resin 100 containing 40 to 60% by weight of the PC resin, 25 to 40% by weight of the SAN resin, and 5 to 20% by weight of the PMMA resin. It may include parts by weight.

According to a preferred embodiment of the present invention, the composite resin composition according to the present invention is a base consisting of a ternary system including a SAN resin, a PC resin, and a PMMA resin having an amount of 30 to 40% by weight of acrylonitrile (AN). The PC resin-SAN resin interface forming a continuous phase in the resin and the carbon nanotubes are selectively arranged in the PMMA resin present at the interface to have a unique dispersion form, compared to the base resin 100 middle portion. By adding only 0.5 to 0.6 parts by weight, even if half of the amount added to the conventional two-component system is added, it has the advantage of improving the electrical conductivity of 2.5 x 10 ^-2 to 3.0 x 10 ^-2 S/cm, which is the same or higher than the conventional one. have.

It should be noted in advance that the content of each component of the base resin included in the composite resin composition according to the present invention to be described below is based on 100% by weight of the base resin. In addition, it is revealed in advance that the carbon nanotubes according to the present invention are in an amount added based on 100 parts of the base resin. If the standard is changed, the changed standard will always be specified, so those of ordinary skill in the art will be able to clearly know what composition the content is based on.

(1) Base resin-Thermoplastic resin

The thermoplastic resin included in the base resin according to an embodiment of the present invention is not particularly limited as long as it is a resin capable of improving compatibility with carbon nanotubes by maintaining a continuous upper structure with the SAN resin.

The thermoplastic resin according to the present invention is a conventional known thermoplastic resin that can be used in the present invention, for example, polycarbonate (PC) resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), rubber modified Polystyrene resin (HIPS), acrylonitrile-styrene-acrylate copolymer resin (ASA resin), methyl methacrylate-butadiene-styrene copolymer resin (MBS resin), acrylonitrile-ethylacrylate-styrene copolymer resin (AES resin), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyvinyl chloride (PVC), copolymers of the above resins, and mixtures thereof. It may include those selected from the group, and is not limited to a specific thermoplastic resin, but a polycarbonate (PC) resin having excellent compatibility with carbon nanotubes by maintaining a continuous top structure with the SAN resin is preferred.

The PC resin according to the present invention may contain 40 to 60% by weight based on the total 100% by weight of the base resin, and preferably may be 55 to 60% by weight. When the content of the PC resin is less than 40% by weight or more than 60% by weight, it is difficult to achieve a mutually continuous structure.

(2) Base resin-Styrene-acrylonitirile (SAN) resin

The SAN resin included in the base resin according to an embodiment of the present invention is not particularly limited as long as it is a resin capable of improving compatibility with carbon nanotubes by maintaining a continuous upper structure with the thermoplastic resin.

The styrenic monomer used to prepare the SAN resin according to the present invention is a conventional known styrene monomer that can be used in the present invention, for example, an aromatic vinyl monomer, such as styrene, alpha-methylstyrene, p-methylstyrene, vinyl One or more mixtures selected from the group consisting of toluene and combinations thereof may be used, and are not limited to a specific styrene monomer, but may be preferably styrene.

The vinyl cyan-based monomer used to prepare the SAN resin according to the present invention is a group consisting of conventionally known vinyl cyan-based monomers that can be used in the present invention, for example, acrylonitrile, methacrylonitrile, and combinations thereof. One or more mixtures selected from may be used, and the mixture is not limited to a specific monomer, but may be preferably acrylonitrile.

The SAN resin according to the present invention may have a weight average molecular weight of 120,000 to 180,000. If the weight average molecular weight is less than 120,000, or exceeds 180,000, there is a disadvantage of insufficient dispersibility.

The SAN resin according to the present invention may contain 60 to 70% by weight of styrene and 30 to 40% by weight of acrylonitirile (AN). If the content of AN is less than 30% by weight, there is a disadvantage that the carbon nanotubes are not evenly distributed at the interface formed in the continuous upper structure with the SAN resin and the thermoplastic resin, and if it exceeds 40% by weight, compatibility with the PC resin is There is a drawback that may occur due to insufficient physical properties.

The SAN resin according to the present invention may include 25 to 40% by weight based on the total 100% by weight of the base resin, and preferably may be 25 to 30% by weight. If the content of the SAN resin is less than 25% by weight or exceeds 40% by weight, the degree of alignment of the carbon nanotubes is reduced, thereby reducing the conductivity.

(3) Base resin-Polymethyl methacrylate (PMMA) resin

The PMMA-based resin contained in the base resin according to an embodiment of the present invention is present in the interface constituting the upper structure while maintaining the upper structure continuously formed by the thermoplastic resin and the SAN resin, thereby improving compatibility with the carbon nanotubes. It is not particularly limited as long as it is a resin that can be improved.

The PMMA-based resin is a conventionally known PMMA-based resin that can be used in the present invention, and may include, for example, a PMMA resin, a PMMA copolymer, and a combination thereof selected from the group consisting of, the PMMA copolymer May include one or more copolymers selected from the group consisting of methyl methacrylate, methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, styrene, and combinations thereof, and specific PMMA-based resins Although not limited to, a PMMA resin capable of selectively interfacial arrangement of carbon nanotubes is preferred.

The PMMA resin preferably uses polymethyl methacrylate having high fluidity in consideration of moldability and impact strength, and may have a weight average molecular weight of 60,000 to 90,000. If the weight average molecular weight is less than 60,000, there is a disadvantage in that the kneading property with PC is insufficient, and when it exceeds 90,000, the moldability is deteriorated.

The PMMA resin according to the present invention may include 5 to 20% by weight based on 100% by weight of the total base resin, and preferably 5 to 10% by weight. If the PMMA resin content is less than 5% by weight or exceeds 20% by weight, there is a disadvantage in that the degree of interfacial alignment of the carbon nanotubes decreases.

(4) Carbon nanotube

The carbon nanotube according to an embodiment of the present invention is capable of improving electrical conductivity even when a small amount is added, and is a tube-shaped material composed of carbons connected in a hexagonal ring shape and can reach several to tens of nanometers in diameter. In addition, the carbon nanotubes are not particularly limited as long as they are not damaged or worn even when used repeatedly, and are chemically stable and excellent in thermal and electrical properties.

The carbon nanotube according to the present invention may be a conventional known carbon nanotube that can be used in the present invention, for example, a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled nanotube, etc. Although not limited, multi-walled nanotubes, which are economical due to relatively low cost, are preferred.

The carbon nanotube according to the present invention preferably has an average diameter of 5 to 15 nm and a length of 40 to 70 μm so as to minimize deterioration of physical properties while exhibiting antistatic properties when kneaded with the thermoplastic resin. If the length of the carbon nanotubes is less than 40 μm, the connectivity may be insufficient, resulting in a decrease in electrical conductivity, and if the length is more than 70 μm, the dispersibility may decrease due to entanglement of the carbon nanotubes themselves.

The carbon nanotubes according to the present invention may be added in an amount of 0.5 to 0.6 parts by weight relative to 100 parts by weight of the base resin. Therefore, in the prior art, the amount of the carbon nanotubes administered to impart the same or excellent battery conductivity in the resin composition is reduced to less than half, and thus has an advantage of excellent economic efficiency.

That is, the composite resin composition according to the present invention is a PC that forms a continuous phase on a base resin consisting of a ternary system including a SAN resin, a PC resin, and a PMMA resin having an amount of 30 to 40% by weight of acrylonitrile (AN). The resin-SAN resin interface and the PMMA resin present at the interface have a unique dispersion pattern in which carbon nanotubes are selectively arranged and arranged, and only 0.5 to 0.6 parts by weight of the carbon nanotubes are added compared to 100 middle parts of the base resin. Thus, even if half of the amount input to the conventional two-component system is added, there is an advantage that the electrical conductivity can be improved to the same or higher than the conventional one.

The manufacturing step of the composite resin composition according to the present invention is Including the step of kneading carbon nanotubes with a base resin including polycarbonate (PC) resin, styrene-acrylonitirile (SAN) resin, and polymethyl methacrylate (PMMA) resin, , The SAN resin is preferably styrene (Styrene) 60 to 70% by weight and acrylonitrile (Acrylonitirile; AN) 30 to 40% by weight.

Specific components and contents related to the PC resin, SAN resin, PMMA resin, and carbon nanotubes may be the same as or different from those described above.

In the manufacturing step, the resins may be added and melt-kneaded through a known apparatus, for example, a batch mixer or a twin-screw extruder.

The kneading speed for preparing the composite resin composition may be 180 to 220 RPM, preferably 190 to 200 RPM. In addition, the kneading temperature may be 230 ~ 260 ℃. If the kneading speed is less than 180RPM, there is a disadvantage of insufficient kneading, and if the kneading speed exceeds 220RPM, excessive shear stress is applied, which may cause a problem of decomposition of the resin or reduction of the length of the carbon nanotube. In addition, when the kneading temperature is less than 230°C, the melt viscosity increases and the extrusion processability is deteriorated, and when it exceeds 260°C, there is a disadvantage that may result in decomposition of the resin.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

Example-Preparation of composite resin composition

Base resin containing 60% by weight of polycarbonate (PC) as a thermoplastic resin, 30% by weight of styrene-acrylonitirile (SAN) resin (32% by weight of acrylonitrile), and 10% by weight of PMMA resin as a PMMA resin 0.5 parts by weight of carbon nanotubes were added to 100 parts by weight and melt-kneaded in a twin screw extruder. The kneading speed was 200RPM and the kneading temperature was adjusted in the range of 230-260°C to prepare a base resin of 3 kg per hour.

Comparative Example 1-Preparation of composite resin composition

When compared with the Example, a composite resin composition was prepared in the same manner as in Example, except that the content of acrylonitrile in the SAN resin was 24% by weight.

Comparative Example 2-Preparation of composite resin composition

Compared with the Example, the PMMA resin was not kneaded, except for kneading with 40% by weight of a styrene-acrylonitirile (SAN) resin (24% by weight of acrylonitrile), and the same composite as the Example. A resin composition was prepared.

Comparative Example 3-Preparation of composite resin composition

When compared with Comparative Example 2, a composite resin composition was prepared in the same manner as in Comparative Example 2, except that the content of acrylonitrile in the SAN resin was 32% by weight.

Experimental Example 1-Evaluation of the dispersion position of carbon nanotubes in the composite resin composition 1

A composite resin composition was prepared according to the above Example and Comparative Example 1, and the dispersion position of the carbon nanotubes was evaluated with a transmission electron microscope without any special treatment.

As a result, referring to FIG. 1A, it can be seen that carbon nanotubes are present in the polycarbonate resin-SAN resin interface and in the PMMA resin existing at the interface.

On the other hand, referring to FIG. 2A, it can be seen that carbon nanotubes exist only on polycarbonate.

That is, when the content of acrylonitrile in the SAN resin in the composite resin composition according to the present invention is 30-40% by weight, the carbon nanotubes are selectively located in the polycarbonate resin-SAN resin interface and the PMMA resin present at the interface. As a result, it can be confirmed that it has a peculiar dispersion form arranged.

Experimental Example 2-Evaluation of the dispersion position of carbon nanotubes in the composite resin composition 2

에서 50분 동안 담궈 폴리카보네이트를 선택적으로 제거한 뒤, 주사전자현미경으로 탄소나노튜브의 분산위치를 평가하였다.A composite resin composition was prepared according to Example and Comparative Example 1, and after cooling, 105 was added to an aqueous NaOH solution (30%).

After immersing in for 50 minutes to selectively remove the polycarbonate, the dispersion position of the carbon nanotubes was evaluated with a scanning electron microscope.

As a result, referring to FIG. 1B, it can be seen that carbon nanotubes exist in the SAN resin and PMMA resin that are left even after the polycarbonate is removed.

On the other hand, referring to FIG. 2B, it was confirmed that carbon nanotubes were not present in the SAN resin and PMMA resin left after the polycarbonate was removed, and it was confirmed that most of the carbon nanotubes were present in the polycarbonate.

That is, when the content of acrylonitrile in the SAN resin in the composite resin composition according to the present invention is 30-40% by weight, the carbon nanotubes are selectively located in the polycarbonate resin-SAN resin interface and the PMMA resin present at the interface. As a result, it can be confirmed that it has a peculiar dispersion form arranged.

Experimental Example 3-Evaluation of electrical conductivity of composite resin composition

Composite resin compositions were prepared according to Examples and Comparative Examples 1 to 3, and compression molded into a film having a thickness of 0.1 to 0.2 mm, and electrical conductivity was evaluated according to ASTM D257 standard.

As a result, when the content of acrylonitrile in the SAN resin in the composite resin composition is 30 to 40% by weight (Example), excellent electrical conductivity of about 2.77 x 10 ^-2 S/cm was exhibited.

On the other hand, when the content of acrylonitrile in the SAN resin in the composite resin composition exceeds 30 to 40% by weight (Comparative Example 1), the electrical conductivity was 100 times or more lower than that of the Example at about 1.21 x 10 ^-4 S/cm. . In addition, when the content of acrylonitrile in the SAN resin in the composite resin composition exceeds 30 to 40% by weight and the PMMA resin is not kneaded (Comparative Example 2), the content of acrylonitrile in the SAN resin in the composite resin composition is 30 to In 40% by weight or when the PMMA resin was not kneaded (Comparative Example 2), the specific resistance value was excessive, so that the electrical conductivity value could not be obtained.

That is, the composite resin composition according to the present invention is a thermoplastic resin that forms a continuous phase on a base resin consisting of a ternary system including a SAN resin, a thermoplastic resin, and a PMMA resin having an acrylonitrile (AN) of 30 to 40% by weight. The carbon nanotubes are selectively located and arranged in the resin-SAN resin interface and the PMMA resin present at the interface, so that the electrical conductivity is improved even if half the amount of the conventional two-component system is added. It has the advantage of being able to.

Claims (11)

Polycarbonate (PC) resin,
Styrene-acrylonitirile (SAN) resin, and
A base resin including a polymethyl methacrylate (PMMA) resin; And
Including carbon nanotubes,
The SAN resin contains styrene (Styrene) 60 to 70% by weight and acrylonitrile (Acrylonitirile; AN) 30 to 40% by weight,
The carbon nanotubes have a PC resin-SAN resin interface; PMMA resin present at the interface; And dispersed within at least one or more positions selected from the group consisting of a combination thereof,
A composite resin composition comprising 0.5 to 0.6 parts by weight of the carbon nanotubes in 100 parts by weight of the base resin. delete The method of claim 1,
The base resin is
40-60% by weight of the PC resin;
25 to 40% by weight of the SAN resin; And
Composite resin composition comprising 5 to 20% by weight of the PMMA resin. delete The method of claim 1,
The SAN resin is a composite resin composition that has a weight average molecular weight of 120,000 to 180,000. The method of claim 1,
The PMMA resin is a composite resin composition having a weight average molecular weight of 60,000 to 90,000. The method of claim 1,
The composite resin composition that the carbon nanotubes are multi-walled carbon nanotubes having an average diameter of 5 to 15 nm and a length of 40 to 70 μm. Including the step of kneading carbon nanotubes with a base resin including polycarbonate (PC) resin, styrene-acrylonitirile (SAN) resin, and polymethyl methacrylate (PMMA) resin, ,
The SAN resin contains styrene (Styrene) 60 to 70% by weight and acrylonitrile (Acrylonitirile; AN) 30 to 40% by weight,
The method for producing a composite resin composition, characterized in that 0.5 to 0.6 parts by weight of the carbon nanotube is added based on 100 parts by weight of the base resin. The method of claim 8,
The base resin is
40-60% by weight of the PC resin;
25 to 40% by weight of the SAN resin; And
Method for producing a composite resin composition containing 5 to 20% by weight of the PMMA resin. delete The method of claim 8,
A method for producing a composite resin composition prepared by kneading at a mixing speed of 180 to 220 RPM and a mixing temperature of 230 to 260°C.

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