KR100757732B1 - Method of preparing a conductive polyurethane foam roller with a high density by an encapsulated type molding - Google Patents

Abstract

A method for preparing a conductive polyurethane foam roller with high density by an encapsulated type molding method is provided to obtain uniform conductivity without the second post process such as dipping by manufacturing a polyurethane foamed liquid containing the ion-complex organic conductive polymer. A method for preparing a conductive polyurethane foam roller with high density by an encapsulated type molding method comprises the steps of: manufacturing a polyurethane foamed liquid containing the ion-complex organic conductive polymer; injecting the polyurethane foamed liquid in a mold in which an over packing rate is 110-250%; and sealing the mold. A block is formed by the sealed mold method.

Description

Method of preparing a conductive polyurethane foam roller with a high density by an encapsulated type molding

1 is a process chart showing a manufacturing method of a high density conductive polyurethane foam roller according to an embodiment of the present invention.

The present invention relates to a method for manufacturing a high density conductive polyurethane foam roller by a closed mold molding method, and more specifically, secondary polyurethane, such as dipping, while maintaining the basic properties and fine cell structure of the polyurethane foam as it is. It relates to a method for producing a high density conductive polyurethane foam roller with uniform conductivity, good wear resistance, elasticity and restoring force, etc. without further processing.

Quality improvement is urgently required in accordance with the market demand of high-end printer products such as color and high-speed printing, and in order to satisfy these properties, a charging roller required for each process such as developing, cleaning, feeding, and conveying inside the toner cartridge is required. Performance of rollers, toner supply rollers, development rollers, development rollers, feed rollers and transfer rollers play a key role. These rollers not only have to have excellent mechanical properties such as wear resistance and surface roughness according to the maximum continuous output, but are also required to have excellent conductivity of the rollers due to the increase in output speed. Conventional conductive rollers include carbon black, metal oxides, ionic compounds, etc. Acrylonitrile butadiene rubber (NBR), ethylene propylene diene rubber (EPDM), silicone Rubbers, polyurethane elastomers, and polyurethane foams.

As a manufacturing method of the conductive polyurethane foam, conductive carbon black is added to the polyurethane raw material for foaming, foaming is performed, and conductive carbon black is mixed and foamed with excess water in a prepolymer, and unreacted water is added. A method of drying and the like have been proposed (Japanese Patent Publication No. 2855335). In order to obtain excellent conductivity in the above method, if the addition amount of conductive carbon black is increased, the viscosity of the mixture increases and foaming is not performed smoothly. It does not have the disadvantages. In order to solve the above problems, as a technique of blending various polyurethanes, a prepolymer composed of a specific polyol and a polyisocyanate is used, and in addition, smooth dispersion of ionic conductive additives other than conductive carbon black and electronic conductive materials and uniform cell stability are pursued. To this end, various dispersing agents and methods using catalysts have been proposed (Japanese Patent Laid-Open Nos. 2003-98786 and 2000-320536).

In general, there are two methods for manufacturing polyurethane foam, a slabstock method for discharging urethane stock solution on a moving conveyor and a mold molding method for discharging urethane stock solution in a predetermined mold. have.

U.S. Patent No. 6,776,745 discloses the manufacture of a conductive polyurethane foam in a manner that imparts conductivity through secondary dipping after the foam block having a density of 40-80 Kg / m 3 is produced by the slabstock method. Doing. Since the patent has a non-uniform conductivity, the resistance stability is unstable at long time, and the change of electrical resistance is large, and the secondary impregnation process has problems such as deterioration in durability such as permanent compression shrinkage. The additional impregnation process by the conductive polymer composition is difficult to have a uniform conductivity, moreover, the slabstock (Slabstock) method is suitable for low-density mass production method, but the production of high-density polyurethane foam of more than 100㎏ / ㎥ impossible. The reason why such high density foams are required is to have the lowest compression reduction rate, namely elasticity and resilience, and good wear resistance.

In order to solve the above problems, the present invention maintains the basic physical properties and fine cell structure of polyurethane foam by hermetically sealed mold method, while maintaining uniform conductivity, excellent wear resistance, and elasticity without secondary post-processing such as dipping. And a method for producing a high density conductive polyurethane foam roller having a restoring force.

The present invention to achieve the above object

Preparing a polyurethane foam comprising an ion-complex organic conductive polymer;

Injecting the polyurethane foam into a mold mold such that the over packing ratio is 110 to 250%; And

Characterized in that the method for producing a high density conductive polyurethane foam roller comprising the step of sealing the mold mold.

The overpacking ratio refers to a value of 100% of the reference volume during free foaming, and preferably 120 to 150%.

The method of manufacturing the conductive polyurethane foam roller may further include forming a block by the sealed mold molding method.

The conductive polyurethane foam roller manufacturing method includes connecting a shaft to the center of the polyurethane foam block, and cutting or polishing a cylindrical foam.

The ion-complex organic conductive polymer is an ion-complex (chemical structure of ion-complex, cation-ion conductive material formed by the coordination bond of at least one selected from alkali metal salts, alkaline earth metal salts and transition metal salts with an ion conductive organic compound Or an anion-ion conducting material.

The polyurethane foaming liquid is 50 to 80% by weight of polyol, 10 to 30% by weight of isocyanate, 0.1 to 2% by weight of catalyst, 2 to 5% by weight of reactive silicone foam stabilizer, 0.5 to 3% by weight of pigment, foaming agent 0.1 to 1.0% by weight, can be prepared using 5 to 40% by weight of the reactive ion-complex organic conductive polymer.

Hereinafter, the present invention will be described in detail.

The present invention comprises the steps of preparing a polyurethane foam comprising an ion-complex organic conductive polymer; Injecting the polyurethane foam into a mold mold such that an overpacking ratio is 110% or more; And a method of manufacturing the conductive polyurethane foam roller, which includes sealing the mold mold. According to the present invention, when molding a polyurethane foam in a closed state of the mold mold, it is possible to produce a high-density foam of 100kg / m ³ or more compared to the conventional slabstock method and can obtain a very fine cell structure. It is possible to produce high-density foam by increasing the pressure when foaming into a closed structure after overpacking. Therefore, for the production of high-density foam, it is preferable to inject the polyurethane foam liquid into the mold by overpacking of 110 to 250%, preferably 120 to 150%, compared to 100% of the free volume. In addition, compared to the slabstock method, which is a free-foaming method under atmospheric pressure conditions, the cell structure is finely formed by foaming in a closed structure, and there is an advantage of minimizing the occurrence of cracks. In addition, by using the mold in a hermetic mold, pressure is formed in the mold during foam molding, thereby obtaining a high density foam. This advantage allows the polyurethane foam rollers according to the invention to provide a high density polyurethane foam roller with uniform and excellent conductivity without further processing.

In general, the slabstock method is a method of cutting and using a free-foamed block, and the mold molding method is a method of manufacturing a mold having a shape that is difficult to cut and injecting the raw material directly into the mold and foaming it.

However, the product to be manufactured in the present invention may be cut and used after being manufactured as a product having a rectangular shape that can also be manufactured by a slab stock method, and thus freely cut and have a desired shape while having a performance that cannot be obtained by the slab stock method. It is an invention that can also be used. In other words, the present invention can be used in the slabstock method, but also has excellent physical properties, which can be achieved only by the overpacking of the closed mold forming method.

1 is a process chart showing a manufacturing method of a high density conductive polyurethane foam roller according to an embodiment of the present invention.

In one embodiment of the present invention, a polyurethane foam liquid raw material mixed with a polyol, an isocyanate, an ion-complex conductive polymer as a main raw material, a foam stabilizer, a catalyst, and the like as a main raw material is added to a mold of a predetermined size whose temperature is controlled to 50 to 80 ° C. Input to overpack 110 ~ 250%.

In the hermetic mold forming method according to the present invention, the overpacking ratio for a mold having a certain shape is 110-250%, preferably 120-150%, in terms of 100% of the standard volume during free foaming. In case of excessively press molding (more than 250%) relative to the volume of the mold, the cell is pressed, and thus the toner supplyability is lowered and the number of independent bubble cells is rapidly increased, which may not be suitable for the purpose of the present invention. Difficult and too pressurized to take time to depressurize, resulting in poor productivity. In addition, if less than 110% has a disadvantage of not obtaining a high-density foam.

After the polyurethane foaming liquid is put into the mold mold and discharged to the mold within 1 to 3 minutes after being sealed, the polyurethane foam can be obtained after molding at 50 ~ 80 ℃.

This is because the urethane reaction generally has to be completed within 3 minutes.

The polyurethane foam cured as described above is manufactured in a desired form through cutting, and is connected to a shaft to polish in a cylindrical shape to produce a conductive roller. High-density conductive polyurethane foam roller according to an embodiment of the present invention, while maintaining the basic physical properties as it is not only excellent conductivity, but also has excellent wear resistance, excellent elasticity and resilience.

The density of the polyurethane foam prepared by the closed mold forming method according to the present invention represented a 100 ~ 250 kg / m ³ , the surface resistance is 10 ⁵ ~ 10 ⁸ Ω / sq when measured by the ASTM D257 method It was.

Polyurethane foam solution to which the ion-complex organic conductive polymer according to an embodiment of the present invention is added to the mold die is 50 to 80% by weight polyol, 10 to 30% by weight isocyanate, 0.1 to 2% by weight catalyst, reactive It can be prepared using 2 to 5% by weight of the silicone foam stabilizer, 0.5 to 3% by weight of the pigment, 0.1 to 1.0% by weight of the blowing agent, 5 to 40% by weight of the ion-complex conductive polymer.

The ion-complex organic conductive polymer is a chemical structure of an ion-complex, and is a cation-ion conducting material or anion-ion formed by coordinating an at least one selected from alkali metal salts, alkaline earth metal salts and transition metal salts with an ion conducting organic compound. It is a conductive material. More specifically, alkali metal cations and transition metal cations are used as conductive cation-ion conducting materials, and include elements such as oxygen, nitrogen, sulfur, phosphorus, etc., which can form ligands for coordination with them. The cation conducting organic compound which is 140 degreeC or more is used. Examples of cationic conducting organic compounds include carbonate, ketone, sulfone, amide, ether, polyol, nitrile, nitrite, phosphate There are organic compounds having phosphonate and acetate groups. More specifically, propylene carbonate (PC), propanediol cyclic carbonate, hydroxybutyric acid lactone, acetonitrile, diphenyl ether, dimethyl formamide (DMF), N-methylacetamide (NMAA), N, N- Dimethylacetamide (DMA), N-methylpropionamide (NMPA), N-methylpyrrolidone (NMP), sulfinylbismethane, and the like may be used together with auxiliary such as ethylene glycol (EG), diethylene glycol, and the like. Polyols and the like can be used, and when using them, they can be used alone or as a mixture. In particular, among them, EG, DMF, DMA, PC, NMP and the like most easily form various types of coordination bonds with the cations of the metal salts according to the present invention.

In addition, the conductive anion-ion conducting material is a counter anion of an alkali metal salt and a counter anion of a transition metal salt, and anion conducting organic compounds having a boiling point of 140 ° C. or higher having an electron accepting function in the molecule are used to bond them. That is, compounds having sulfoxide, ester, sulfate, phosphate, phosphite, and imide groups are used. More specifically, trilauryl phosphite, dipropylene glycol phosphite, poly dipropylene glycol phosphate, phosphoric acid trischloroethyl ester, triisodecyl phosphite, dichloropropanol phosphate, diphenylhydrogen phosphate, tris chloromethyl ester, dimethyl Sulfoxides (DMSO) and the like can be used, either alone or in combination thereof. When the antistatic agent prepared by using a boiling point of less than 140 ℃ to the polymer resin is added to the antistatic effect due to the molecular weight decrease during thermoforming, the physical properties of the molded product is caused.

Metal salts used in the present invention include alkali metal salts, that is, salts such as lithium, sodium, potassium, and alkaline earth metal salts such as magnesium, calcium, and the like, specifically, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiAsF ₆ , LiC (CF ₃ SO ₃ ) ₃ , LiN (CF ₃ SO ₃ ) ₂ , LiI, LiBr, LiCl, LiF, NaPF ₆ , NaClO ₄ , NaI, NaSCN, KSCN, KPF ₆ , KClO _4, etc. The transition metal salts include all metal salts including Fe, Ni, Cu, Zn, and more specifically, FeCl ₃ , FeCl ₂ , FeBr ₃ , FeBr ₂ , FeI ₂ , FeI ₃ , Fe (CH ₃ COO) ₃ , Fe (SCN) ₃ , CuCl, CuBr, CuI, CuCN, CuCl ₂ , CuBr ₂ , CuI ₂ , Cu (NO ₃ ) ₂ , Cu (CH ₃ COO) ₂ , Cu (SCN) ₂ , ZnCl ₂ , ZnBr ₂ , ZnI ₂ , Zn (CH ₃ COO) ₃ and the like are used alone or in a mixture. Generally, the amount used is 5 to 40% by weight of the total weight, most preferably 20 to 35% by weight. When used less than 5% by weight, the electrical conductivity is low, it does not have an antistatic function, when using more than 40% by weight causes a change in physical properties.

The method for preparing the ion-complex organic conductive polymer will be described in detail. First, the metal salt is placed in a cationic conductive organic compound and heated with vigorous stirring to form a coordination compound. The reaction time is from 1 hour to 24 hours. Upon completion of the reaction, anion conducting organic compounds are added to the reaction product and heated with vigorous stirring for an additional 1 hour to 24 hours. The coordination reaction is then completed under reduced pressure in vacuo to give the final solution. After the reaction mixture has cooled to room temperature, an unreacted metal salt is removed using a filter.

The ion-complex organic conductive polymer solution can form additional secondary coordination bonds with the polyether or polyester functional groups of the urethane polymer chain, thereby exhibiting more uniform and stable antistatic performance.

As the components of the polyol constituting the polyurethane raw material of the present invention, polyether polyol, polyester polyol, polytetramethylene ether glycol, THF-alkylene oxide air Copolymer polyols, acrylic polyols, polyolefin polyols, and the like. As the isocyanate component, a polyisocyanate type of at least two functional groups or more may be used, and toluene diisocynate (TDI), ortho toluidine diisocynate (TODI), naphthalene diisocynate (naphthalene diisocynate: NDI), xylene diisocynate (XDI), methylene diphenyl diisocynate (MDI) and carbodiimide modified MDI such as aromatic isocyanates, aliphatic isocyanates, substituted isocyanates, and derivatives thereof Can be.

Hereinafter, the present invention will be described in detail by the following examples. However, the embodiments are not intended to limit the technical scope of the present invention.

Example  One

68% by weight of polyol (the polyether polyol having a molecular weight of 4,000 to 6,000 and 10 to 30% of ethylene glycol (EO) in the structure), 20.7% by weight of polyisocyanate (M-MDI, NCO content: 28%), 1.4 wt% crosslinking agent (1,4-butanol), 0.1 wt% metal catalyst (Stannous octoate), 1.3 wt% foam stabilizer (silicone-based material), ion-complex organic conductive polymer (SR 6005, Nano Chem Tech. Co., KOREA 7% by weight, 1 part by weight of pigment, and 0.5% by weight of blowing agent (H ₂ O) were mixed to prepare a polyurethane foam.

The prepared polyurethane foam was poured into the mold of a certain size (36 cm x 50 cm x 6 cm) at a temperature of 60 ° C. within 1 minute so that the overpacking ratio was 130%, and the mold was molded at 60 ° C. for 10 minutes. It removed, hardened | cured at normal temperature, the cutting process, etc. were obtained, and the electrically conductive polyurethane foam was obtained. A foam roller was manufactured by connecting a shaft to the conductive polyurethane foam prepared as described above and polishing the cylindrical shape. The physical properties of the foam were 115 kg / m 3, the cell size was 90 PPI, and the permanent compressive shrinkage was 10%. The surface resistance of the antistatic roller was 10E6Ω / sq by ASTM D257.

Example  2-4

Polyurethane foam prepared in the same manner as in Example 1 in the mold of a certain size (width 25 cm x height 50 cm x height 6 cm) at a temperature of 60 ℃ 110% (Example 2), 150% (Example 3), 200% (Example 4) was immediately added, and after molding at 60 ° C. for 10 minutes, taken out of the mold, cured at room temperature, cut processing was performed to obtain a conductive polyurethane foam.

Comparative example  One

The polyurethane foam liquid prepared in the same manner as in Example 1 was cured by molding and curing in a slabstock method, which is a free-foaming method under atmospheric pressure, to obtain an antistatic polyurethane foam.

Experimental Example  : Measuring property

1. Density: The density of the foam of 300 x 300 x 50 mm was measured and the density was calculated using the formula of mass / volume.

2. Surface resistance: Antistatic polyurethane foam was applied by applying a DC voltage of 100V and measuring the current value was calculated by converting the current value to the resistance value. (ASTM D257).

3. Cell size: Photographs were taken at a magnification of 40 to 70 times with an optical microscope, and then the number of cells in a linear image within 1 inch was measured.

4. Permanent Compression Reduction Rate: The rate of change in thickness after 50% compression and standing at 70 ° C. for 22 hours was measured (JIS K6402).

5.Compression reduction rate (%) = (sample thickness before test-sample thickness after test) / sample thickness before test

According to the above method, the physical properties of the antistatic polyurethane foams prepared in Examples 1 to 4 and Comparative Example 1 were measured and shown in Table 1.

Comparison of Properties of Antistatic Polyurethane Foam with Variation of Overpacking Rate Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Density (Kg / m ³ ) 115 100 140 180 60 Surface resistance (Ω / sq) 10E5 10E6 10E5 10E5 10E9 ^* Cell size (PPI) 90 80 100 100 60 Percent Compression Reduced (%) 10 10 20 25 15

* Cell size (PPI): Pore Per Inch-Since the number of pore per 1 ich, the larger the value, the finer the cell structure.

Polyurethane foam (Examples 1 to 4) produced in a closed mold method according to the present invention as shown in Table 1 is higher in density and excellent surface resistance than the comparative example 1 in the slabstock method, permanent compression extrusion It can be seen that the tone is low. In addition, the size of the cell is fine, it is possible to produce a high-density conductive polyurethane foam having excellent conductivity and excellent wear resistance, elasticity, restoring force, etc., without additional post-processing.

Example  5

Except for adding the content of the blowing agent (H ₂ O) in Example 1 to 0.2% by weight (Example 5), 1.0% by weight (Example 6) to prepare a polyurethane foam prepared in the same manner. , Polyurethane foam was prepared into a mold of a certain size (25 cm x 50 cm x 6 cm in height) which is temperature controlled at 60 ° C., and the foamed liquid was added within 1 minute to have an overpacking ratio of 130%, 60 After molding at 10C for 10 minutes, the mold was taken out of the mold, cured at room temperature, cut, and the like to obtain an antistatic polyurethane foam.

Comparative example  2 and Comparative example  3

Antistatic in the same manner as in Example 5 except that the proportion of the content of the blowing agent (H ₂ O) in Example 5 was added by weight 1.2% by weight (Comparative Example 2), 1.5% by weight (Comparative Example 3), respectively Polyurethane foam was obtained.

In order to compare the physical properties of the antistatic polyurethane foam according to the ratio of the amount of blowing agent added, the physical properties of the antistatic polyurethane foam prepared in Example 5 and Comparative Examples 2 to 3 are shown in Table 2 according to the experimental example.

Comparison of Properties of Antistatic Polyurethane Foam According to the Ratio of Foaming Agent Addition Example 1 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Density (Kg / m ³ ) 115 180 80 60 40 Surface resistance (Ω / sq) 10E5 10E5 10E9 10E8 10E9 Cell size (PPI) 90 95 60 60 60 Percent Compression Reduced (%) 10 10 15 15 15

It can also be seen that when limiting the content of the blowing agent according to the invention as shown in Table 2, a more dense polyurethane foam can be produced.

The present invention is to produce a polyurethane foam to which the ion-complex organic conductive polymer is added through a closed mold molding method, it is possible to produce a foam of high density fine cell structure without further processing, semi-permanent conductivity, excellent wear resistance, elasticity and resilience Conductive polyurethane foam rollers suitable for copiers, printers, facsimiles and the like can be provided. Therefore, the present invention can provide a conductive roller which is very suitable as a toner supply roller in a cartridge in an image forming apparatus such as a color and a high speed printer, and a manufacturing method thereof.

The present invention is to produce a polyurethane foam to which the ion-complex organic conductive polymer is added through a closed mold molding method, it is possible to produce a foam of a high density fine cell structure without further processing, semi-permanent conductivity, excellent wear resistance, elasticity and resilience Conductive polyurethane foam rollers suitable for copiers, printers, facsimiles and the like can be provided. Therefore, the present invention can provide a conductive roller which is very suitable as a toner supply roller in a cartridge in an image forming apparatus such as a color and a high speed printer, and a manufacturing method thereof.

Claims (10)

Preparing a polyurethane foam comprising an ion-complex organic conductive polymer; Injecting the polyurethane foaming liquid into a mold with an overpacking ratio of 110 to 250%; And Method of manufacturing a high density conductive polyurethane foam roller comprising the step of sealing the mold. The method of manufacturing a high density conductive polyurethane foam roller according to claim 1, wherein the overpacking ratio is 120 to 150%. The method of manufacturing a high density conductive polyurethane foam roller according to claim 1, wherein the manufacturing method of the conductive polyurethane foam roller further comprises forming a block by the closed mold molding method. The method of claim 1, wherein the manufacturing method of the conductive polyurethane foam roller further comprises the step of connecting the shaft to the central portion of the polyurethane foam block, cutting or polishing the cylindrical foam, characterized in that the high density conductive poly. Method of producing urethane foam roller. The method of manufacturing a high density conductive polyurethane foam roller according to claim 1, wherein the polyurethane foam comprises 0.1 to 1.0 wt% of a blowing agent based on the total weight of the foam. The polyurethane foam according to claim 1, wherein the polyurethane foam is 50 to 80% by weight of polyol, 10 to 30% by weight of isocyanate, 0.1 to 2% by weight of catalyst, 2 to 5% by weight of reactive silicone foam stabilizer, 0.5 to 3% by weight of pigment, 0.1 to 1.0% by weight of blowing agent and 5 to 40% by weight of ion-complex conductive polymer. The method of claim 1, wherein the ion-complex organic conductive polymer is an ion-complex chemical structure, at least one selected from alkali metal salts, alkaline earth metal salts, transition metal salts and the coordination bond of the ion conductive organic compound. Method for producing a high density conductive polyurethane foam roller, characterized in that the cation-ion conductive material or anion-ion conductive material formed by. The method of manufacturing a high density conductive polyurethane foam roller according to claim 7, wherein the ion conductive organic compound is a cationic conductive organic compound or anionic conductive organic compound having a boiling point of 140 ° C or higher. The compound according to claim 8, wherein the cationic conducting organic compound is propylene carbonate, propanediol cyclic carbonate, hydroxybutyric acid lactone, acetonitrile, diphenyl ether, dimethyl formamide, N-methylacetamide, N, N-dimethyl A process for producing a high density conductive polyurethane foam roller, characterized in that it is a mixture of one or two or more selected from acetamide, N-methylpropionamide, N-methylpyrrolidone, sulfinylbismethane, ethylene glycol, diethylene glycol. The method of claim 8, wherein the anion conducting organic compound is trilauryl phosphite, dipropylene glycol phosphite, poly dipropylene glycol phosphate, tris chloroethyl ester, triisodecyl phosphite, dichloropropanol phosphate, diphenylhydrogen A process for producing a high density conductive polyurethane foam roller, characterized in that it is a mixture of one or two or more selected from phosphate, tris chloromethyl ester and dimethyl sulfoxide.

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