JPS6342791B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an acrylic conductive fiber for use in static elimination brushes that has excellent fibrillation resistance, and more specifically, it is used to wipe toner after visible image formation in electronic copying machines using a photoconductive phenomenon. The surface fibers are constantly rubbed when used, such as static eliminating brushes for sheets such as paper and film, or static eliminating brushes used for antistatic fabric products such as antistatic work clothes and antistatic cloth. The present invention relates to acrylic conductive fibers useful as fibers for static elimination brushes. (Prior art) Conventionally, a latent image is formed on a photoconductor master and developed, which is widely used in electronic copying machines using photoconductive phenomena, and then the image is electrostatically transferred to ordinary paper. In other words, in the electrostatic printing method that uses static electricity, when a latent image is developed and transferred with toner, a visible image is transferred to paper in order to give an electric charge to the toner, and then the visible image is transferred onto a photosensitive master or in the image area. Unnecessary toner remains due to the electrical charges generated. In order to obtain a clear image, it was necessary to eliminate this electrical charge and wipe off the residual toner. In addition, in the paper and film manufacturing process during printing, it is necessary to effectively remove static electricity charges that impede the process. Conventionally, brushes or rubber blades made of raised fibers such as animal hair and rayon have been used to wipe toner from copying machines and remove static electricity from paper and film. Also, there were problems in that the static electricity removal effect was insufficient, the durability was poor, and the image and product surface were easily damaged during use. In order to solve these problems, attempts have been made to use fluffy fibers, metal fibers, carbon fibers, and other conductive fibers as the nap of the plush, but these fibers have the following drawbacks: be. First, although the frictional resistance of the soft fibers is small, they have no practical effect in preventing the above-mentioned problems caused by static electricity, and the metal fibers have the effect of preventing the problems caused by static electricity, but they do not have the ability to recover from mechanical deformation, and are not rigid. It has the fatal drawback of damaging the image area. Although carbon fiber has excellent anti-static properties, it has the disadvantage that it is easily broken and may damage images, although not as much as metal fiber. Furthermore, conventional conductive fibers are flexible, do not damage images, and have a good static electricity removal effect. Due to repeated friction and abrasion or repeated discharge of charged charges, the tips of the fibers become finely cracked, become fibrillated, and eventually fall off, resulting in toner clogging and loss of wiping action. Ta. That is, typical examples of the cross-sectional shape of a conventional composite type conductive fiber in which a conductive portion and a non-conductive portion are bonded to each other are shown in FIGS. 1A, B, and C. In the figure, the shaded area is the conductive part. When the present inventors observed conventional conductive fibers with fibrillated tips under a microscope, it was observed that the conductive part and non-conductive part were separated at the interface without exception. It has been found that the adhesion between the conductive part and the non-conductive part constituting the composite conductive fiber does not have enough adhesive force or peeling resistance to withstand the friction and abrasion caused by the raised bristles of the static elimination brush. What should be noted is that once the tip of the conductive fiber is even slightly peeled off, the peeling continues to grow in the axial direction of the fiber, further promoting fibrillation of the fiber. In other words, for these conventional conductive fibers,
Due to its fiber structure, fibrillation cannot be avoided, and its practical performance as a nap for static elimination brushes is not fully satisfied. (Problems to be Solved by the Invention) The purpose of the present invention is to provide antistatic properties required for the raised brushes of toner removal or static electricity removal brushes.
We provide acrylic conductive fibers for use in static elimination brushes that have excellent properties such as discharge deterioration resistance, abrasion resistance (fibrillation resistance), flexibility, and recovery from deformation required for the raised naps exposed on the surface. There is something to do. (Means for Solving the Problems) The object of the present invention is to achieve the invention described in the claims, namely, to use an acrylonitrile (hereinafter abbreviated as AN)-based polymer as a fiber-forming polymer component, An acrylic type in which a polyalkylene glycol-based polymer containing carbon black is used as an antistatic polymer component, and the antistatic polymer component is dispersed in a fiber-forming polymer in the form of fibrils and a network structure. An acrylic conductive fiber for use in a static elimination brush, in which the antistatic polymer component and the fiber-forming polymer component are bonded by a third component polymer comprising a copolymer of polyalkylene glycol and AN. This can be achieved by conductive fibers. That is, the present invention uses a polyalkylene glycol polymer containing carbon black as an antistatic polymer constituting a conductive part, and combines this antistatic polymer component with a fiber-forming polymer constituting a nonconductive part. The component AN-based polymer is dispersed and oriented along the fiber axis direction to form a fine fibrillar network structure, and the conductive portion and non-conductive portion are combined with the polyalkylene glycol of the third component polymer. It is characterized in that fibrillation is prevented by bonding with AN through a copolymer. In other words, the fiber-forming polymer of the non-conductive part of the present invention is made of an AN-based polymer, and the antistatic polymer of the conductive part is made of a specific polymer such as a polyalkylene glycol-based polymer containing carbon black. Although acrylic conductive fibers have excellent conductivity, their biggest drawback in practical use as fibers for static elimination brushes is fibrillation due to contact with the object to be neutralized and discharge deterioration due to static elimination. In order to effectively prevent this, it is only possible to use the copolymer of polyalkylene glycol and AN as the third component. FIG. 2 and FIG. 3 are a schematic cross-sectional view and a schematic vertical cross-sectional view, respectively, showing one embodiment of the acrylic conductive fiber of the present invention, and in the figures, 1 is a conductive part;
Reference numeral 2 indicates a non-conductive portion, and 3 indicates a third component polymer layer that joins the conductive portion 1 and the non-conductive portion 2. In addition, as can be seen from the cross section in the fiber axis direction in FIG. The third component polymer is interposed in the two to disperse the interfacial cohesive force between the two, thereby dispersing the peeling stress between the two. The AN polymer of the fiber-forming polymer constituting the acrylic conductive fiber of the present invention may be any AN polymer used in the production of known acrylic fibers, and is not particularly limited. . Further, as the polyalkylene glycol polymer of the antistatic component polymer, polyalkylene glycol polymers such as polyethylene glycol and polypropylene glycol, block polyether polyester copolymers of polyalkylene glycol polymers and polyesters, Examples include block polyether polyamide copolymers of polyalkylene glycol polymers and polyamides, and polymers obtained by graft copolymerizing AN with these copolymers.
You may use more than one species in combination. Among these antistatic component polymers, preferred is a modified block polyether polyester copolymer obtained by graft copolymerizing AN, especially a block polymer of 60 to 95% by weight polyalkylene glycol and 5 to 40% by weight polyester. It is preferable to graft copolymerize 5 to 60% by weight of AN. The blending ratio of the fiber-forming polymer component and the antistatic polymer component is preferably from 2 to 30% by weight, preferably from 5 to 25%, based on the combined weight of both. If it is less than 2%, the antistatic properties of the resulting fibers will not be sufficient, and if it exceeds 30%, the flexibility of the resulting fibers will be greatly reduced, which is not preferable. Further, the blending ratio of carbon black to the antistatic polymer component is 15 to 100% by weight, preferably
A range of 20 to 60% is preferable. The third component polymer that joins the interface between the fiber-forming polymer component and the antistatic polymer component has an intermediate polymer composition between the fiber-forming polymer component and the antistatic polymer component. It is necessary that the polymer is a copolymer of polyalkylene glycol and AN, and such a copolymer is
By using it as a component polymer, the bond between the fiber-forming polymer component and the antistatic polymer component is strengthened, and the antistatic properties of the conductive fibers are maintained while achieving the object of the present invention. This makes it possible to greatly improve the drawbacks such as fibrillation resistance and discharge deterioration resistance. Here, the copolymers of polyalkylene glycol and AN include the aforementioned polyethylene glycol, polypropylene glycol, or polyethylene polypropylene glycol copolymers, and AN.
Examples include random copolymers, block copolymers, and graft copolymers with polyalkylene glycol, and the copolymer composition should have properties approximately intermediate between polyalkylene glycol and AN, and their solubility coefficients should be taken into account. It is better to design the More specifically, within the range of ±30%, preferably within the range of ±20% of the main component ratio determined from the weight average composition of each of the fiber-forming polymer component and the antistatic polymer component. If it exceeds 30%, the conductivity of the antistatic polymer component will not be sufficiently reflected in the resulting fibers, which is not preferable. The blending ratio of the third component polymer is preferably 5 to 50% by weight based on the total weight of both the fiber-forming polymer component and the antistatic polymer component. If it is less than 5%, the interfacial cohesive force between the conductive component and the non-conductive component of the resulting fiber will decrease, and the effect of improving the fibrillation resistance will not be sufficient, and if it exceeds 50%,
This is not preferable because the conductivity of the antistatic polymer component will not be sufficiently reflected in the resulting fibers. The method for producing the acrylic conductive fiber of the present invention includes adding a polyalkylene glycol-based polymer containing carbon black as an antistatic polymer component to an AN-based polymer as a fiber-forming polymer component; Three-component polymer polyalkylene glycol and
It is produced by applying a mixed spinning method in which a copolymer with AN is mixed and this polymer mixture is spun, and in detail, the spinning method described in JP-A-52-103525 is adopted. It can be manufactured by Next, a practical method for constructing brush naps using the conductive fibers will be described. It is preferable that the conductive fibers constituting the brush nap be made up of 100% conductive fibers from the viewpoint of anti-static properties, but the invention is not necessarily limited to this, and may vary depending on the type of device to be applied or the electrical characteristics. Alternatively, it is possible to mix it with non-conductive fibers depending on the mechanical properties. For example, if a special wiping force is required, increasing the mixing ratio of non-conductive fibers will increase the wiping power proportionally, but the antistatic performance will decrease inversely. can be considered to be determined by the required characteristics. That is, it is preferable to select and design the mixing ratio of non-conductive fibers within a range where antistatic performance can be maintained. The content of conductive fibers must be 40% or more, preferably 60% or more. If the conductive fibers contained in the brush naps are less than 40%, the desired antistatic effect cannot be obtained, so in the case of a toner wiping brush, unnecessary charges may worsen toner detachment and reduce the amount of residual toner. increases, making it difficult to obtain clear images. In addition, when removing static electricity from sheet-like materials such as paper or film,
The amount of residual charge becomes so large that it is no longer possible to reduce electrostatic damage. Any type of non-conductive fiber may be used, but in order to avoid damaging the object it comes into contact with, it is necessary to select, for example, a thinner fiber, a flexible fiber, a fiber with a small coefficient of friction, etc. be. And, the composition ratio is such that the ratio of the antistatic polymer main component constituting the third polymer to the fiber-forming polymer main component is equal to the weight of the antistatic polymer composition and the fiber-forming polymer composition. It is desirable that the ratio be within ±30% of the main component ratio determined from the average composition. Since the conductive fibers of the present invention are structured as described above, the tips do not easily become fibrillated even when used as a brush brush. , the durability has been significantly improved and clear images can be obtained for a long time, and since the brush napped can be made of conductive fibers, it does not damage the image area unlike metal fibers. Needless to say, the static elimination brush does not cause fibrillation even when brought into contact with a charged object, does not damage the object it comes into contact with, and can prevent problems caused by static electricity. As mentioned above, the conductive fiber of the present invention exhibits particularly great merits when used for the nap of wiping brushes and static eliminating brushes, but it goes without saying that it can also be used in antistatic fabrics such as antistatic work clothes and antistatic cloth. Needless to say, it can also be effectively used for industrial antistatic materials such as antistatic conveyor belts and antistatic ropes. The present invention will be explained in detail with reference to Examples, Comparative Examples, and Comparative Examples. In the following explanation, the anti-frosting property (frosting occurrence time), which indicates the degree of anti-fibrillation, is measured by the following method. It is. Anti-frosting property (frosting occurrence time): Prepare a cigarette-shaped sample by pulling the samples to 100,000 D, and set the length of the fluff tip to 2 mm and the total length.
20mm, 5mm in diameter, 200g with ART pill tester
The time required for fibrillation to begin to form from the tip of the single fiber is observed using a stereomicroscope, and this is expressed as the frosting generation time. That is, the friction time required until frosting begins to occur is used as an evaluation measure of anti-frosting properties, and the longer this time, the more difficult it is to form fibrillations. Example 1 Various conductive fibers shown in Table 1 (single denier
2.5d) was prepared and the degree of fibrillation resistance (anti-frosting property) was examined. Acrylonitrile polymer (hereinafter referred to as AN)
A ₁ was prepared by dimethyl sulfoxide solution polymerization of AN/methyl acrylate/sodium allylsulfonate (93.6/6.0/0.4) mole %. Antistatic polymer B ₁ consists of polyethylene adipate and polyethylene glycol (molecular weight 4000) (20/
80) AN was further graft-polymerized to a block polyether ester prepared to have a weight percent of 80). The composition ratio of AN and block polyether ester was (30/70) wt%, and graft polymerization was carried out in dimethyl sulfoxide using ammonium persulfate as a catalyst. On the other hand, as a third polymer, a vinyl monomer is copolymerized with block polyether ester to form a polymer.
C ₁ and C ₂ were created respectively. Polymer _C1 used AN as a vinyl monomer, and the composition ratio of AN and block polyether ester was (65/35) wt%. Styrene was used as the vinyl monomer for polymer _C2 , and the composition ratio of styrene and block polyether ester was (65/35) wt%. Carbon black was added to and mixed with a dimethyl sulfoxide solution of antistatic polymer B ₁ to prepare a conductive polymer solution, and this and AN-based polymer A ₁ were mixed and spun to obtain conductive fiber F ₁ . . The amount of carbon black added to the conductive fiber _F1 was 6 wt%, and the electrical resistivity was 7×10 ³ Ω·cm. Antistatic polymer B ₁ , carbon black, and third polymer C ₁ were mixed and spun into AN polymer A ₁ to produce conductive fiber F ₂ . The amount of third polymer _C1 added is
The amount of carbon black added was 6wt%, and the electrical resistivity was 5×10 ³ Ω·cm. Similarly, antistatic polymer B ₁ and a third polymer are added to carbon black.
Conductive fiber _F3 was prepared by adding _C2 and spinning the mixture with AN polymer. The electrical resistivity of the conductive fiber F ₃ was 6×10 ³ Ω·cm. On the other hand, as a fiber-forming polymer, conductive fibers are made by using 66 nylon and eccentrically composited with conductive polymers.
Created _F4 . The conductive polymer was 610 nylon containing 25% by weight of carbon black, and the core component ratio was 10% by weight. The electrical resistivity of the conductive fiber F ₄ was 2×10 ⁴ Ω·cm. The anti-frosting properties of these four types of conductive fibers were evaluated, and the results are shown in Table 1. The results of this experiment show that the conductive fiber F ₂ in which a polymer having a composition intermediate between a fiber-forming polymer and an antistatic polymer is added as the third polymer is difficult to fibrillate. Even if a polymer having no affinity with the fiber-forming polymer is added as the third polymer, no improvement in anti-frosting property is observed. In order to confirm the performance of these conductive fibers, we knitted a fabric with a pile length of 10 mm and wrapped it around a metal cylinder with a diameter of 60 mm to make a circular brush. Table 2 shows the results of a copying test in which cellulose acetate fiber _F5 was also added for comparison. When 5,000 copies were made and the stains were compared, it was clear that the brush using the conductive fiber _F2 of the present invention showed particularly excellent performance. When I observed these brushes, I found that they were conductive fibers.
Fibrillation was observed in the conductive fibers other than _F2 , and it was confirmed that toner was mixed between the fibrils and caused copying stains, and it was also found that the wiping effect was reduced.

【table】

[Table] Example 2 Antistatic polymer consisting of methoxypolyethylene glycol methacrylate/AN (50/50) wt%
B ₂ was made by solution polymerization of dimethyl sulfoxide. On the other hand, apart from this, a third polymer C ₃ , C ₄ , C ₅
was polymerized. Polymer C ₃ is a copolymer of methoxypolyethylene glycol methacrylate and AN, Polymer C ₄ is a copolymer of methoxypolyethylene glycol methacrylate and methyl acrylate, and Polymer C ₅ is a copolymer of methoxypolyethylene glycol methacrylate and glycidyl methacrylate. The composition ratio was (25/75) wt% in both cases. Obtained in Example 1 in the same manner as in Example 1
The AN polymer A ₁ , the antistatic polymer B ₂ , carbon black, and the third polymer C ₃ , C ₄ , and C ₅ were mixed and spun to form conductive fibers (monocarbons) as shown in Table 3. Yarn denier 2.5d) F ₆ , F ₇ , F ₈ , and F ₉ were prepared, and the anti-frosting properties were evaluated and the results are shown. As the third polymer, a polymer C ₃ having an intermediate composition between the fiber-forming polymer A ₁ and the antistatic polymer B ₂
It can be seen that the conductive fiber F7 of the present invention to which _F7 is added has particularly excellent anti-frosting properties. The electrical specific resistance of conductive fiber F ₇ is 1×10 ⁴ Ω・cm
It was good. When a brush was prepared in the same manner as in Example 1 and a copying test was conducted, almost no stains were observed even after copying 5000 sheets, confirming that the brush had superior performance compared to conventional products.

【table】

[Table] Example 3 Conductive fibers of the present invention (single yarn denier 2.5d) F ₂ , F ₄ prepared in Example 1, commercially available metal fibers (diameter 25 μ) and carbon fibers (single yarn denier) as comparative examples.
1d), length 1m, nap length 20mm, density 2
g/m, and a current collector potential measuring device (Kasuga Denki Co., Ltd.) is installed 25 cm in front and behind the static eliminating brush.
Table 4 shows the results of measuring the charging voltage of a polyester film (thickness: 70 μm, width: 1 m) while running at a speed of 10 m/min. Fibrillation resistance was determined by observation using a stereomicroscope after 100 hours of cumulative running. As can be seen from the results of this practical test, conductive fiber F ₂ to which a polymer having an intermediate composition between a fiber-forming polymer and an antistatic polymer was added as the third polymer had a short distance to the film. 0, that is, the piloerection did not fibrillate even when brought into contact. The nylon-based composite conductive fiber _F4 was fibrillated, and some parts with white tips were also observed. The carbon fibers were found to have broken and shortened ends, and the raised ends of the metal fibers were slightly widened, indicating poor recovery from deformation. On the other hand, there is no problem with the static elimination effect for any sample as long as the brush and film are not in contact with each other, but for samples made of raised fluff other than those of the present invention, if they are kept in contact for a long time, the static elimination performance will slightly decrease over time. I understand that.

[Table] Example 4 The conductive fiber of the present invention (single yarn denier 2.5d) F ₂ prepared in Example 1 was mixed into polyester filament (single yarn denier 2.0d), and the same procedure as in Example 3 was carried out. Length 1m, nap length 20mm, density 2g/
m, the mixing ratio (weight percent) of conductive fibers is
We have produced 10%, 30%, 40%, 50%, 70%, and 100% static elimination brushes. This brush was placed in contact with the polyester film running at a speed of 10 m/min as described in Example 3, and one end was grounded and charged using a current collector potential measuring device (KS-325 model manufactured by Kasuga Denki Co., Ltd.). The voltage was measured. As shown in Figure 4, at a mixing ratio of around 40%, the result is less than half of the original charging voltage, and the value is
It can be seen that the potential is as low as 2.2kV, and in order to further reduce the potential to 1kV or less, it is necessary to include 60% or more of conductive fibers. In addition, as a result of evaluating the fibrillation resistance,
There was no problem with fibrillation even after 50 hours of continuous use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional basic composite conductive fiber, and FIG. 2 is a schematic cross-sectional view illustrating a conductive fiber used in the present invention to which a third polymer is applied.
Figure 3 is a longitudinal cross-sectional view of the conductive fiber of the present invention in which fine fibrils in the conductive part form a network structure in the non-conductive part, and Figure 4 shows the relationship between the mixing ratio of the conductive fiber and the charging voltage. It is a diagram. 1: conductive part, 2: non-conductive part, 3: third polymer.

Claims (1)

[Claims] 1 An acrylonitrile-based polymer is used as a fiber-forming polymer component, a polyalkylene glycol-based polymer containing carbon black is used as an antistatic polymer component, and the antistatic polymer component forms fibrils in the fiber-forming polymer. In the acrylic conductive fibers dispersed in a network structure, the antistatic polymer component and the fiber-forming polymer component are a third component consisting of a copolymer of polyalkylene glycol and acrylonitrile. Acrylic conductive fibers for static elimination brushes bonded by polymer.