KR101425370B1 - Electrical Conductive Resin Composition and Transfer Belt using Thereof - Google Patents

Abstract

The present invention relates to a conductive resin composition containing 65 to 90 wt% of base resin formed of a polyimide resin, a polyurethane imide resin, or a mixture thereof; 5 to 30 wt% of conductive filler formed of carbon black, a carbon nanofiber, a carbon nanotube, or a mixture of at least one selected therefrom; and 1 to 5 wt% of conductive inorganic filler formed of silver, nickel, copper, tellurium, or a mixture of at least one selected therefrom, and a transfer belt using the same. According to the present invention, the carbon black, the carbon nanofiber, and the carbon nanotube used in the conductive resin composition are used in a mixture, and thus the carbon black consumption can be reduced and a protrusion level can be significantly reduced among surface characteristics. Also, the surface smoothing characteristics and mechanical and electrical characteristics required by the transfer belt can be satisfied despite the low carbon black consumption.

Description

Technical Field [0001] The present invention relates to a conductive resin composition and a transfer belt using the conductive resin composition.

The present invention relates to a conductive resin composition for producing a transfer belt for use in an image forming apparatus or the like using an electrophotographic method, and a transfer belt using the same.

In recent years, information devices such as personal computers, digital video cameras, digital cameras, and camera-equipped mobile phones have become high-performance and high-capacity, so that color information such as photographs and images can be easily handled.

An electrophotographic apparatus such as a copying machine and a printer is required not only to realize color but also to express high image quality at high speed and to use compact and general purpose paper.

In order to achieve the above-mentioned object, the intermediate transfer belt system is mainly adopted for the transfer process of the electrophotographic apparatus, and thus the transfer belt is becoming an important component.

Resins such as polycarbonate (PC), polyvinylidene fluoride (PVDF), polyamideimide (PAI), polyimide (PI) resin and rubber are used as the material of the intermediate transfer belt.

The transfer belt for the image forming apparatus is usually required to have a large resistivity (surface resistivity) in the circumferential direction of the belt and a resistivity (volume resistivity) in the thickness direction smaller than the surface resistivity, Environment, voltage, or the like.

In addition, the transfer belt has a high tensile modulus of elasticity in the circumferential direction of the belt, a smooth surface and a large contact angle, so that the toner must be easily transferred from the belt to the transfer material (paper) (Excellent non-staining property), and flame retardancy.

On the other hand, the semiconductive thermoplastic resin composition used for producing the intermediate transfer belt is usually prepared by mixing / dispersing a conductive material such as carbon black in a thermoplastic resin.

However, carbon black that imparts conductivity to a semiconductive material has a critical content that can be filled due to the inherent properties of the carbon black itself, for example, electrical conductivity and mechanical characteristics. As a result, When black is included, the electrical properties and stiffness of the semiconductive material are increased, but surface smoothness and impact strength and flowability are weakened, and thus the fluidity of the base resin is decreased, so that the dispersibility of carbon black can be reduced.

As an example of such an example, Japanese Patent Publication No. 2,560,727 discloses a method of dispersing carbon black in polyimide and using the same in a transfer belt. However, this method is troublesome to be prepared in a solution state in order to disperse carbon black of 10 wt% .

In addition, in the case of U.S. Patent No. 5,021,036, it has been disclosed that 5 to 20% by weight of acetylene black is dispersed in polycarbonate to prepare a transfer belt. However, the transfer belt has a problem in that dispersion property and physical properties of the high- have.

In general, the film constituting the transfer belt can be produced by dispersing carbon black having conductivity in a resin such as polycarbonate, polyimide, polyamideimide or fluorine resin, but it is difficult to uniformly disperse the carbon black in accordance with the use of excessive carbon black , There is a problem that the physical properties are reduced.

Furthermore, the use of a conductive material such as carbon black increases the deviation of the transfer belt depending on the region thereof, thereby decreasing the durability. Further, peeling of the base resin such as polycarbonate, polyimide, polyamideimide, There is a problem that the strength is reduced.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a conductive resin composition, preferably a conductive resin composition for use in an image forming apparatus using an electrophotographic system, And mechanical properties.

Further, the present invention can manufacture a transfer belt, preferably a transfer belt for an image forming apparatus, using the conductive resin composition.

The present invention

65 to 90% by weight of a base resin composed of a polyimide resin, a polyurethane imide resin or a mixture thereof;

5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And

And 1 to 5% by weight of a conductive inorganic filler composed of silver, nickel, copper, tellurium or a mixture of at least one selected from the foregoing.

In addition,

65 to 90% by weight of a base resin composed of a polyimide resin, a polyurethane imide resin or a mixture thereof;

5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And

And 1 to 5% by weight of a conductive inorganic filler composed of silver, nickel, copper, tellurium or a mixture of at least one selected from the foregoing.

The conductive resin composition may further comprise 1 to 5 parts by weight of a conductive filler dispersant and / or 1 to 10 parts by weight of an additive comprising triazole, triazine, imidazole, or a mixture of at least one selected from the foregoing, based on the total weight of the resin composition can do.

On the other hand, the transfer belt may be configured such that an elastic layer is formed on a substrate containing a conductive resin composition.

By using carbon black, carbon nanofibers, and carbon nanotubes mixed in the conductive resin composition in combination, it is possible to reduce the amount of carbon black used to significantly reduce the level of protrusions in the surface characteristics, It is possible to satisfy the surface smoothness characteristics, mechanical and electrical characteristics required by the transfer belt in spite of the use thereof.

Further, the present invention provides the electrical characteristics of the conductive resin composition by using the conductive inorganic filler composed of silver, nickel, copper, and tellurium as well as the conductive filler composed of carbon black, carbon nanofiber and / or carbon nanotube , The mechanical strength can be increased.

Hereinafter, the present invention will be described in detail.

In one aspect, the present invention provides a resin composition comprising 65 to 90% by weight of a base resin comprising a polyimide resin, a polyurethane imide resin or a mixture thereof; 5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And 1 to 5% by weight of a conductive inorganic filler composed of silver, nickel, copper, tellurium or a mixture of at least one selected from the foregoing.

In another aspect, the present invention relates to a resin composition comprising 65 to 90% by weight of a base resin comprising a polyimide resin, a polyurethane imide resin or a mixture thereof; 5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And 1 to 5% by weight of a conductive inorganic filler composed of silver, nickel, copper, tellurium or a mixture of at least one selected from the foregoing.

The conductive resin composition may further comprise 1 to 5 parts by weight of a conductive filler dispersant and / or 1 to 10 parts by weight of an additive comprising triazole, triazine, imidazole, or a mixture of at least one selected from the foregoing, based on the total weight of the resin composition can do.

The conductive resin composition according to the present invention is used for producing a transfer belt to be applied to an image forming apparatus using an electrophotographic method, and is not particularly limited as long as it is a conventional conductive resin composition having such a purpose.

The conductive resin composition according to the present invention comprises 65 to 90% by weight of a base resin composed of a polyimide resin, a polyurethane imide resin or a mixture thereof; 5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And 1 to 5% by weight of a conductive inorganic filler composed of silver, nickel, copper, tellurium or a mixture of at least one selected from them.

Here, the base resin is intended to improve properties such as mechanical properties, electrical properties, and appearance of articles produced using a conductive resin composition, for example, a film and a transfer belt. Any conventional polyimide resin, polyurethane imide resin or a mixture thereof may be used.

The polyimide resin is not particularly limited, but may be prepared by imidizing a polyamic acid synthesized from an acid anhydride and a diamine compound with heat and a catalyst, and preferred examples of the polyimide resin include a dianhydride monomer And one or two diamine monomers, and then use a polyimide resin represented by the following formula (1).

[Formula 1]

Herein, n is an integer of 3 or more and 1,000 or less, R1 is a tetravalent aromatic or aliphatic organic group, and R2 is a divalent aromatic or aliphatic organic group.

The polyurethane imide resin is not particularly limited as long as it is a polyurethane imide resin that is commonly used in the art, but preferably one or two dianhydride monomers, diamine monomers, dialcohol monomers and isocyanate monomers It is preferable to use a polyurethane imide resin represented by the following general formula (2).

[Formula 2]

Herein, 1 and m are integers of 1 to 50, R3 is a divalent aliphatic organic group having a weight average molecular weight of 1,000 to 3,000, and R4 is a divalent aromatic or aliphatic organic group.

The conductive filler according to the present invention is used for improving the electrical conductivity and mechanical properties of the conductive resin composition by mixing with a base resin to form a matrix type structure. Any conductive filler common in the art having such a purpose can be used However, it is preferable to use carbon black, carbon nanofibers, carbon nanotubes, or a mixture of at least one selected from these.

In this case, the mixing ratio of the carbon black, the carbon nanofibers, and the carbon nanotubes constituting the conductive filler is not particularly limited. However, in the case of maintaining the high conductivity while reducing the amount of the conductive filler, the carbon nanofibers and / Carbon nanotubes can be used.

In this case, the carbon nanofibers and the carbon nanotubes may be mixed at a weight ratio of 3: 7 to 7: 3, preferably 5: 5, or the carbon nanofibers or the carbon nanotubes may be used alone.

However, if the amount of the low-cost carbon black used as the conductive filler is reduced, the manufacturing cost of the conductive resin composition may increase, so it is preferable to adjust the mixing ratio according to the user's choice.

On the other hand, when the carbon black, the carbon nanofibers or the carbon nanotubes constituting the conductive filler are all mixed, the conductive filler preferably comprises 10 to 70 parts by weight of carbon black; 15 to 45 parts by weight of carbon nanofibers; And 15 to 45 parts by weight of carbon nanotubes, but the present invention is not limited thereto.

The carbon black according to the present invention is not particularly limited, but it is preferable to use carbon black having a particle size of 10 to 50 nm and a surface area of 60 to 150 m ² / g, more preferably acetylene black or furnace black It is good to do.

The carbon nanotubes according to the present invention can be classified into single-walled carbon nanotube (SWCNT), multi-walled carbonnanotube (MWNT), and multi-walled carbon nanotube (rope carbonnanotube).

Here, the single-walled nanotube is a tube type having one wall composed of carbon atoms and has the best electric conductivity and thermal conductivity. However, since it is difficult to purify and has high manufacturing cost, it is used in a small amount in the transparent electrode field and semiconductor field.

In addition, double walled nanotubes composed of carbon atoms have excellent electrical conductivity and mechanical properties.

In addition, the multi-walled nanotube is a tube in which a plurality of walls composed of carbon atoms are formed in a single tube, and its electrical and thermal properties are somewhat lowered. However, the multi-walled nanotube is excellent in mechanical properties, easy to manufacture and relatively low in cost and has a wide range of industrial applicability. In addition, there is a bundle of nanotubes (Rope Nanotube) in the form of bundles of bundles of single-walled nanotubes.

However, the carbon nanotube according to the present invention may be any of the above-described single-wall, double wall, multi-wall or multi-wall carbon nanotubes, or a mixture thereof, but preferably has a diameter of 5 to 40 nm Walled carbon nanotubes having an aspect ratio (length / diameter) of about 100 to 1,000 are preferably used.

The conductive inorganic filler according to the present invention is used in combination with the conductive filler to improve the electrical characteristics of the conductive resin composition and to increase the mechanical strength.

Preferred conductive inorganic fillers include silver, nickel, copper, tellurium, or a mixture of at least one selected from these.

In a specific embodiment, the conductive resin composition according to the present invention may further comprise 1 to 5 parts by weight of the conductive filler dispersant based on the total weight of the resin composition.

Here, the conductive filler dispersant may be a conductive filler, specifically, carbon nanofibers and / or carbon nanotubes may be deagglomerated through steric stabilization of the carbon nanotubes, and the carbon nanofibers and / or carbon nanotubes may have the same charge To generate an electric repulsive force of the carbon nanofibers and / or the carbon nanotubes to prevent re-aggregation of the carbon nanofibers and / or the carbon nanotubes and to disperse them. Any conventional dispersant in the art for this purpose is not particularly limited Preferably, however, it is preferred to use a polymeric copolymer having a pigment-affinity group, preferably a polyester-based block copolymer.

Specifically, the conductive filler dispersant according to the present invention is based on a functionalized polymer having a number average molecular weight of 10,000 to 40,000 g / mol, preferably 25,000 to 35,000 g / mol, more preferably about 30,000 g / mol It is preferable to use a dispersant.

The dispersant may be a polymer or copolymer having a group having a functional group and / or a pigment affinity, an alkylammonium salt of a polymer or a copolymer, a polymer or copolymer having an acid group, a comb copolymer or a block copolymer, A block copolymer having groups having affinity, particularly a basic group having a group having pigment affinity, an optionally modified acrylate block copolymer, an optionally modified polyurethane, an optionally modified and / or chlorinated polyamine, Polymers or copolymers with phosphoric acid esters, ethoxylates, fatty acid radicals, optionally modified polyacrylates, such as transesterified polyacrylates, optionally modified polyesters such as acid-functional polyesters, Polyphosphates, or mixtures thereof.

In the dispersion operation using such a dispersant, pretreatment such as pretreatment of the dispersed carbon nanofibers and / or carbon nanotubes, for example, oxidation, chemical treatment, heat treatment, polarization or halogenation, The dispersant does not require the pretreatment described above for dispersion.

Here, the dispersion of the carbon nanofibers and / or the carbon nanotubes in handling is very large because of the nature of the carbon nanofibers and / or the carbon nanotubes and the van der Waals force, which is the cohesive force between the particles, Should be taken into account. If the addition amount of the dispersant is too small, the effect of dispersing the carbon nanofibers and / or the carbon nanotubes can not be expected. On the contrary, when the amount of the dispersant is large, the opposite effect is caused by the viscosity of the dispersant itself. Should be selected by the user considering this point.

In another specific embodiment, the conductive resin composition according to the present invention may further comprise 1 to 10 parts by weight of an additive comprising triazole, triazine, imidazole, or a mixture of at least one selected from the group consisting of triazine, triazine, and imidazole.

Here, the additive improves the heat resistance of the base resin, for example, polyimide and / or polyurethane imide resin, and is made of a resin composition, for example, a film or a transfer agent Minimizes belt-to-belt variation to improve durability.

The conductive resin composition according to the present invention having such a constitution is used for producing a transfer belt to be applied to a transfer belt, preferably an image forming apparatus using electrophotography.

Here, the electrical resistance of the transfer belt is not particularly limited, but is preferably 10 ^-6 to 10 ^-13 Ω.

Preferred transfer belts include: 65 to 90% by weight of a base resin made of a polyimide resin, a polyurethane imide resin or a mixture thereof; 5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And 1 to 5% by weight of a conductive inorganic filler composed of silver, nickel, copper, tellurium or a mixture of at least one selected from them.

The conductive resin composition may further comprise 1 to 5 parts by weight of a conductive filler dispersant and / or 1 to 10 parts by weight of an additive comprising triazole, triazine, imidazole, or a mixture of at least one selected from the foregoing, based on the total weight of the resin composition can do.

In a specific aspect, the transfer belt according to the present invention may have an elastic layer formed on a substrate made of a conductive resin composition.

At this time, the elastic layer includes an imide-modified polyurethane elastomer.

In another specific embodiment, the transfer belt according to the present invention can form a fluororesin layer by coating a fluororesin on the elastic layer.

Here, the fluororesin layer improves the releasability of the transfer belt.

On the other hand, the thickness of the elastic layer is not particularly limited, but if it is thinner than 50 탆, flexibility required by the elastic layer is lowered. If it is larger than 1,000 탆, the total thickness of the belt is increased, It is preferable to have a thickness of 50 to 1,000 mu m, more preferably 100 to 200 mu m.

The fluororesin layer preferably has a thickness of 5 to 50 占 퐉, preferably 10 to 30 占 퐉.

If the thickness of the fluororesin layer is less than 5 탆, sufficient releasability is not obtained and durability is reduced. If the thickness is more than 50 탆, the flexibility of the elastic layer may be impaired.

Hereinafter, the present invention will be described in detail by way of examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[Example 1]

77 g of polyimide resin, 20 g of carbon black and 3 g of copper were mixed to prepare a conductive resin composition.

[Example 2]

77 g of polyimide resin, 10 g of carbon nanofibers, 10 g of carbon nanotubes and 3 g of copper were mixed to prepare a conductive resin composition.

[Example 3]

77 g of polyimide resin, 10 g of carbon black, 5 g of carbon nanofiber, 5 g of carbon nanotube and 3 g of copper were mixed to prepare a conductive resin composition.

[Example 4]

77 g of a polyurethane imide resin, 10 g of carbon black, 5 g of carbon nanofibers, 5 g of carbon nanotubes and 3 g of silver were mixed to prepare a conductive resin composition.

[Example 5]

A conductive resin composition was prepared in the same manner as in Example 3 except that 3 g of conductive filler dispersant [BYK-9077, BYK-Chemie GmbH, Germany] was further mixed.

[Example 6]

The procedure of Example 3 was repeated except that 5 g of imidazole was further mixed to prepare a conductive resin composition.

[Example 7]

The conductive resin composition prepared according to Example 1 was injected into a centrifugal molding machine heated to about 120 ° C.

Then, the centrifugal molding machine drum is rotated at a speed of 500 rpm to stretch the conductive resin composition over the entire drum.

Then, the rotation speed of the centrifugal molding machine drum was maintained at 1,000 rpm, followed by heat treatment for 30 minutes, followed by cooling to room temperature to prepare a transfer belt.

[Examples 8 to 12]

A transfer belt was produced in the same manner as in Example 7 except that the conductive resin compositions prepared in Examples 2 to 6 were used in place of the conductive resin compositions prepared in Example 1, respectively.

[Example 13]

The conductive resin composition prepared according to Example 1 was injected into a centrifugal molding machine heated to about 120 ° C.

Then, the centrifugal molding machine drum is rotated at a speed of 500 rpm to stretch the conductive resin composition over the entire drum.

Then, the rotation speed of the centrifugal molding machine drum was maintained at 1,000 rpm, followed by heat treatment for 30 minutes, followed by cooling to about 60 DEG C to produce a film.

Then, the centrifugal molding machine drum was rotated at a speed of 500 rpm, and an imide-modified polyurethane elastomer solution was injected into the inner surface of the prepared film, followed by heat treatment and cooling to room temperature to prepare a transfer belt having an elastic layer.

[Comparative Example 1]

70 g of polyimide resin and 30 g of carbon black were mixed to prepare a conductive resin composition.

Then, the conductive resin composition was injected into a centrifugal molding machine heated to about 120 ° C.

Then, the centrifugal molding machine drum is rotated at a speed of 500 rpm to stretch the conductive resin composition over the entire drum.

Then, the rotation speed of the centrifugal molding machine drum was maintained at 1,000 rpm, followed by heat treatment for 30 minutes, followed by cooling to room temperature to prepare a transfer belt.

[Comparative Example 2]

A conductive resin composition obtained by mixing 70 g of polyimide resin, 27 g of carbon black, and 3 g of copper was used in place of the conductive resin composition obtained by mixing 70 g of polyimide resin and 30 g of carbon black.

[Comparative Example 3]

A conductive resin composition obtained by mixing 80 g of polyimide resin, 17 g of carbon black and 3 g of silver was used in place of the conductive resin composition obtained by mixing 70 g of polyimide resin and 30 g of carbon black.

[Experiment]

The electrical and mechanical properties of the transfer belt produced according to Examples 7 to 13 and Comparative Examples 1 to 3 were measured and shown in Table 1 below.

Electrical resistance (O) Dispersibility (surface smoothness)
(Amount of Tips / 300) At room temperature (23) Elastic modulus Peel strength The tensile strength
(kg /) Elongation rate
(%) (Pa) (N / 10 mm) Example 7 10 ^-6 0 1.775 465 2.2 x 10 ⁷ 3.4 Example 8 10 ^-12 0 1.910 408 2.5 x 10 ⁷ 3.2 Example 9 10 ^-8 0 1.851 420 2.3 x 10 ⁷ 3.6 Example 10 10 ^-8 0 2.025 560 2.4 x 10 ⁷ 3.9 Example 11 10 ^-10 0 1.843 410 2.3 x 10 ⁷ 3.8 Example 12 10 ^-7 0 2.047 560 2.4 x 10 ⁷ 5.4 Example 13 10 ^-6 0 1.862 486 5.1 x 10 ⁷ 4.1 Comparative Example 1 10 ^-6 2 1.808 573 2.3 x 10 ⁷ 0.1 Comparative Example 2 10 ^-8 6 1.650 471 1.9 x 10 ⁷ 1.5 Comparative Example 3 10 ^-6 6 1.690 449 1.8 x 10 ⁷ 1.4

As shown in Table 1, both Examples and Comparative Examples show the electrical resistance required for the transfer belt. However, in the comparative examples, the content of carbon black, which is a conductive material, is increased to obtain a desired electrical resistance value, And the mechanical properties such as tensile strength and elongation were not good.

In Example 13, an elastic layer was formed on the surface of the substrate constituting the transfer belt, and the elastic modulus was higher than in the other Examples.

As described above, those skilled in the art will understand that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the embodiments described above are all illustrative and not restrictive. The scope of the present invention should be construed as being included in the scope of the present invention without departing from the scope of the present invention.

Claims (5)

65 to 90% by weight of a base resin composed of a polyimide resin, a polyurethane imide resin or a mixture thereof;
5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And
Silver, 1 to 5% by weight of a conductive inorganic filler consisting of nickel, copper, tellurium or a mixture of at least one selected from the group consisting of nickel,
The polyimide resin may be synthesized by using one or two kinds of dianhydride monomers and diamine monomers,

[Formula 1]
Herein, n is an integer of 3 or more and 1,000 or less, R1 is a tetravalent aromatic or aliphatic organic group, and R2 is a bivalent aromatic or aliphatic organic group.
delete delete 65 to 90% by weight of a base resin composed of a polyimide resin, a polyurethane imide resin or a mixture thereof;
5 to 30% by weight of a conductive filler consisting of carbon black, carbon nanofibers, carbon nanotubes or a mixture of at least one selected from the foregoing; And
And 1 to 5% by weight of a conductive inorganic filler composed of silver, nickel, copper, tellurium or a mixture of at least one selected from the foregoing,
Wherein the transfer belt comprises an elastic layer formed on a substrate made of a conductive resin composition, and a fluororesin layer coated with a fluororesin at an upper end of the elastic layer.
delete