JP2000320684A - Resin composition for seal sliding member and seal sliding member using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity and economy while holding sealing function by dispersing and including grease in thermoplastic elastomer and forming a resin composition for a seal sliding member. SOLUTION: In manufacturing a seal sliding member 1 suited for being used for a part in contact with a fine powder body, or toner in particular in a copying machine, a cylindrical bearing part 2 and an annular lip part 3 for pivoting a rotary shaft are treated by a resin composition including grease and thermoplastic elastomer so as to be integrally formed. The lip part 3 is projected inward from one end side of the bearing part 2 in the radial direction and inclined in the direction of the bearing part 2 and the shape of the lip part 3 is formed into an acute cross section as gradually thinning its thickness from the root side toward the tip side. The seal sliding member 1 is so formed that the lip part 3 abuts on the outer circumferential face of the rotary shaft to be fitted into the bearing part 2 while applying a presser force thereto so that the lip part 3 can prevent the leakage of the toner via the seal sliding member 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing and a rotary shaft seal sliding member suitable for use in a developing section of a copying machine, a printer, a facsimile or the like, particularly a portion which comes into contact with fine powder such as toner. The present invention relates to a resin composition used for the above.

[0002]

2. Description of the Related Art Conventionally, a bearing 101 having a sealing function as shown in FIG. 7 and a rotating shaft 111 having a sealing function as shown in FIG. And a configuration in which the toner does not leak from the developing unit.

A bearing 101 having a sealing function is provided on a bearing portion 102 for supporting a rotating shaft, a rubber O-ring 103 mounted on the outer periphery of the bearing portion 102, and one end of a bearing surface of the bearing portion 102. And a rubber seal 104 to be formed.
The O-ring 103 prevents the toner from leaking from the outer periphery of the bearing 101 with a sealing function, and a rubber seal 104.
The bearing 10 with the sealing function is formed by the annular lip 105.
This prevents toner from leaking from between 1 and the rotating shaft. The bearing portion 102 is made of polyacetal having self-lubricating properties, and the O-ring 103 and the rubber seal 104 are made of nitrile rubber, fluorine rubber, or the like.

The rotating shaft 111 with a sealing function includes a cylindrical shaft portion 112 and a hollow short cylindrical seal portion 113 fitted to the shaft portion 112. The seal portion 113 is in contact with a housing 114 on which the shaft portion 112 is supported, thereby preventing toner from leaking. The shaft portion 112 is made of metal, resin, or the like, and the seal portion 113 is made of a foam made of urethane resin or the like.

[0005]

The bearing 101 with a seal function and the rotary shaft 111 with a seal function, which are the conventional seal sliding members, have the following inconveniences. That is, (1) The bearing 101 with a sealing function is satisfactory in the function of sealing the toner and the function as a bearing. However, a plurality of components including the bearing portion 102, the O-ring 103, and the rubber seal 104 are combined. Due to the configuration, assembling the bearing with seal function 101 requires time and effort. In addition, since these parts include expensive parts (especially the rubber seal 104), it is inevitable that the cost as a whole product increases.

(2) Similarly, since the rotating shaft 111 with a sealing function has a configuration in which the shaft portion 112 and the sealing portion 113 are combined, it is difficult to assemble and the cost is increased.

(3) In order to avoid such difficulty in assembly,
A bearing 101 with a seal function has been developed in which the bearing 101 with a seal function is integrally formed of a rubber material used for the rubber seal 104, and the rubber seal 104 and the O-ring 103 which are separate from the bearing section 102 have been developed. However, there is a problem that the cost is increased. Therefore, the rubber material constituting the bearing with the sealing function was changed and the manufacturing method was improved.However, the improvement was not satisfactory from the structural limit, and on the contrary, there was a problem that the sealing function was reduced. Has occurred.

The present invention has been made in view of these disadvantages, and a resin composition for a seal sliding member capable of improving productivity and economy while maintaining a sealing function, and a seal using the same. The purpose is to provide a sliding member.

[0009]

Means for Solving the Problems The invention made to solve the above problems is a resin composition for a seal sliding member in which grease is dispersed and contained in a thermoplastic elastomer. Grease is generally composed of a base oil such as a synthetic oil or a mineral oil and a thickener such as a stearate or a urea compound, and the thickener retains the base oil to form a semi-solid state. Has become. Therefore, the grease contained in the resin composition is dispersed in a form in which the thickener incorporates the base oil, so that the base oil is prevented from spouting from the resin composition, and stable friction resistance and wear for a long period of time are obtained. Function can be exhibited.

Therefore, a seal slide using the resin composition and having one of a shaft portion and a bearing portion and an annular lip portion for preventing powdery foreign matter such as toner from entering a sliding portion thereof. When the moving member is formed integrally, the frictional resistance and wear of the sliding portion can be stably reduced for a long period of time.

The grease content is 2% by weight or more and 2% by weight or more.
It is preferably 0% by weight or less. If the grease content is less than 2% by weight, the above-mentioned functions of reducing frictional resistance and wear cannot be sufficiently exhibited.
When it exceeds 0% by weight, in the production of the resin composition,
This is because kneading with an extruder or the like becomes difficult.

The grease is based on hydrocarbon oil,
Lithium stearate may be used as the thickener. The reason why the hydrocarbon oil is used as the base oil is that even if it oozes into the sliding portion, it does not easily adversely affect the thermoplastic elastomer and peripheral parts. In addition, when lithium stearate is used as the thickener, the grease is susceptible to interactions such as polarity and hydrogen bond in the molecular structure, and as a result, the base oil can be stably retained in the material, and the frictional resistance and It is possible to promote stabilization of the function of reducing wear and prolongation of the function.

The thermoplastic elastomer is JIS-A
Those having a hardness of 80 or more and 90 or less are preferable. This is because if the JIS-A hardness of the thermoplastic elastomer is smaller than the above range, deformation occurs at the time of removal from a mold or the like, and the productivity is reduced. Conversely, if the JIS-A hardness exceeds the above range, This is because the contact force at the sliding portion is large, and the toner is fused by frictional heat, which may further increase the sliding resistance. Here, "JIS-A hardness" is defined as JIS
Means the hardness by the spring type hardness test (A type) specified in the above.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings as appropriate. 1 to 4 are schematic cross-sectional views showing a seal sliding member according to the first to fourth embodiments of the present invention, respectively.

A seal sliding member 1 shown in FIG. 1 is a bearing with a sealing function, and a cylindrical bearing portion 2 for supporting a rotating shaft and an annular lip portion 3 are integrally formed of a resin composition described later. Things. The lip 3 protrudes from one end of the bearing 2 inward in the radial direction and inclined in the direction of the bearing 2. In addition, the shape of the lip portion 3 is reduced in thickness from the root side to the tip (inner diameter end) side, that is, the cross-sectional shape is formed at an acute angle.

The seal sliding member 1 comes in contact with the outer peripheral surface of the rotating shaft fitted to the bearing portion 2 while the lip portion 3 exerts a pressing force. The lip 3 prevents toner from leaking through the seal sliding member 1. Therefore, a rubber seal or the like, which is necessary for the conventional bearing to prevent the intrusion of the fine powder such as the toner, becomes unnecessary.

The resin composition constituting the seal sliding member 1 contains grease and a thermoplastic elastomer. Conventionally, there has been a means of containing mineral oil to provide self-lubricating properties to the seal sliding member.However, if only mineral oil is used, the mineral oil easily blows out onto the surface of the molded product, thereby reducing frictional resistance and wear. The function of reducing is not stably exhibited for a long time. In addition, a silicone-modified urethane-based thermoplastic elastomer (trade name “Rezamin PS” manufactured by Dainichi Seika Co., Ltd.)
-22490 "), a urethane-based thermoplastic elastomer containing a fluorine-based lubricant (trade name" Milactran F598FCOO "manufactured by Nippon Milactran Co., Ltd.) and the like were used to improve friction resistance and wear resistance. There are some, but the wear is large and it is not suitable for seal sliding members. Since the seal sliding member 1 contains grease, it is possible to solve the problems caused by the above-described conventional means and to stably reduce frictional resistance and wear for a long period of time. In order to effectively exert such an effect, the grease content is 2% by weight.
The content is preferably not less than 20% by weight or less.

The thermoplastic elastomer used in the resin composition is not particularly limited, and examples thereof include olefin, styrene, ester, amide, urethane, silicone, and fluorine. . However, ester-based, amide-based, and urethane-based thermoplastic elastomers have abrasion resistance and are suitable for seal sliding members. JIS of the thermoplastic elastomer
-A hardness is preferably 80 or more and 90 or less.

The grease used in the resin composition is not particularly limited, and general grease can be used. However, for the ester-based, amide-based, and urethane-based thermoplastic elastomers, grease containing hydrocarbon oil as a base oil and lithium stearate as a thickener is preferable. This is because these greases are particularly susceptible to interactions such as polarity and hydrogen bond in the molecular structure, and can stably retain the base oil in the material.

As a method of manufacturing the seal sliding member 1, a method of injection-molding the above-described resin composition into a mold having the same internal space as the seal sliding member 1 is preferable. According to such injection molding, a product having a complicated shape can be easily manufactured.

The seal sliding member 4 of FIG. 2 is similar to the seal sliding member 1 of FIG. 1 in that the bearing portion 5 and the lip portion 6 are integrally formed of a resin composition. However, the lip portion 6 is inclined such that its tip is separated from the bearing portion 5 to enhance the effect of preventing toner from entering the bearing portion 5 side.
The resin composition of the seal sliding member 4 is the same as the resin composition of the seal sliding member 1.

The seal sliding member 7 of FIG. 3 is similar to the seal sliding member 4 of FIG. 2 in that a bearing portion 8 and a lip portion 9 inclined outward are integrally formed. However, the seal sliding member 7 is different from the seal sliding member 4 described above.
The ridge 10 is integrally formed on the cylindrical outer peripheral surface.
The ridge 10 protrudes in a semicircular cross section, and is continuous for one round in the circumferential direction. The ridges 10 have the effect of preventing toner leakage without using an O-ring, which is necessary for a conventional bearing. Further, by forming the ridges 10 integrally, leakage of toner can be prevented. The completeness of the effect can be increased. Note that the resin composition of the seal sliding member 7 is the same as the resin composition of the seal sliding member 1, and the frictional resistance is reduced and the wear resistance is improved.

The seal sliding member 11 shown in FIG. 4 is a rotary shaft having a sealing function, and has a cylindrical shaft portion 12 and an annular lip portion 13.
Are formed integrally with the resin composition. The lip portion 13 has the same shape as the lip portion 3 described above, and is formed so as to come into contact with the housing 14 when the shaft portion 12 is supported by the housing (bearing) 14.
This prevents toner leakage from between the housing 2 and the housing 14. The resin composition of the seal sliding member 11 is the same as the resin composition of the seal sliding member 1,
Reduction of frictional resistance and improvement of wear resistance are achieved.

[0024]

Hereinafter, the present invention will be described in detail with reference to Examples.
Of course, the present invention should not be construed as being limited based on the description of this embodiment.

(1) Experiment 1 [Example 1] An amide-based thermoplastic elastomer having a JIS-A hardness of 83 (trade name "TPAE" manufactured by Fuji Chemical Co., Ltd.)
-10HP ") and 100 parts by weight of synthetic oil-based grease (" Maltemp D No.
2)) 6.95 parts by weight were kneaded with a Henschel mixer, and the kneaded product was formed into pellets with an extruder.
The seal sliding member of Example 1 was obtained by forming the same shape as the seal sliding member 7 of FIG. 3 by injection molding. The synthetic oil-based grease uses synthetic oil as a base oil and lithium stearate as a thickener.

Example 2 100 parts by weight of a urethane-based thermoplastic elastomer having a JIS-A hardness of 83 (trade name "Rezamin P2183" manufactured by Dainichi Seika Co., Ltd.) and a synthetic oil-based grease (Kyodo Yushi ( A seal sliding member of Example 2 was obtained in the same manner as in Example 1 except that 6.95 parts by weight of a product name “Multemp SC-C” manufactured by K.K. The synthetic oil-based grease uses a synthetic oil as a base oil and an aromatic urea as a thickener.

Example 3 100 parts by weight of an ester-based thermoplastic elastomer having a JIS-A hardness of 83 (trade name "Hytrel 3083" manufactured by Toyobo Co., Ltd.) and grease (manufactured by Kyodo Yushi Co., Ltd.) (Product name "Excelite EP")
A seal sliding member of Example 3 was obtained in the same manner as in Example 1 except that 14 parts by weight was used. The grease is
It uses an ester synthetic oil as a base oil and an aromatic urea compound as a thickener.

Example 4 100 parts by weight of an olefin-based thermoplastic elastomer having a JIS-A hardness of 83 (trade name "PER T310E" manufactured by Tokuyama Corporation) and grease (manufactured by Kyodo Yushi Co., Ltd.) Product name "Excelite E
P ") A seal sliding member of Example 4 was obtained in the same manner as Example 1 except that 14 parts by weight was used.

Example 5 100 parts by weight of a styrene-based thermoplastic elastomer having a JIS-A hardness of 83 (trade name "TR2003" manufactured by JSR Corporation) and grease (a product manufactured by Kyodo Yushi Co., Ltd.) (Exelite EP) was used in the same manner as in Example 1 except that 14 parts by weight of the seal sliding member of Example 5 was obtained.

Comparative Example 1 Bearing 10 with Seal Function of FIG. 7
In the same manner as in Example 1, an O-ring and a rubber seal were attached to a bearing portion made of polyacetal to obtain a seal sliding member of Comparative Example 1.

[Evaluation of Characteristics] Using the seal sliding members for bearings of Examples 1 to 5 and Comparative Example 1, an experiment was conducted to evaluate the presence or absence of toner leakage. As shown in FIG. 5, an evaluator 15 used in this experiment has a pair of seal sliding members 17 fitted to both ends of a cylindrical housing 16 and one cylindrical sliding member 17 is fitted to the pair of seal sliding members 17. The stainless steel rotary shaft 18 is supported. The rotating shaft 18 has a motor 19 connected to one end thereof, and an agitating screw 20 for agitating the toner on the outer peripheral portion. Further, the inside of the housing 16 was filled with toner. The evaluation device 15 was operated for 1000 hours, and the presence or absence of toner leakage was examined. The results are shown in Table 1 below.

[0032]

[Table 1]

As shown in Table 1, the seal sliding members of Examples 1 to 5 did not leak toner, and had the same sealing function and bearing function as the seal sliding member of Comparative Example 1. confirmed. Further, it can be seen that the seal sliding members of Examples 1 to 5 can greatly reduce the number of parts and are excellent in productivity and economical efficiency as compared with the seal sliding member of Comparative Example 1.

(2) Experiment 2 [Example 6] An amide-based thermoplastic elastomer having a JIS-A hardness of 90 (trade name "TPAE" manufactured by Fuji Kasei Co., Ltd.)
-8 ") and 100 parts by weight of synthetic oil-based grease (trade name" Multemp D No. 2 "manufactured by Kyodo Yushi Co., Ltd.)
95 parts by weight were kneaded with a Henschel mixer, and the kneaded material was formed into pellets with an extruder, and then formed into the same shape as the seal sliding member 11 of FIG. 4 by injection molding. A seal sliding member was obtained.

Example 7 100 parts by weight of a urethane-based thermoplastic elastomer having a JIS-A hardness of 90 (trade name "Rezamin P4070" manufactured by Dainichi Seika Co., Ltd.) and a synthetic oil-based grease (Kyodo Yushi ( Example 6 except for using 6.95 parts by weight of a product name "Multemp SC-C" manufactured by KK Corporation.
In the same manner as in the above, a seal sliding member of Example 2 was obtained.

Comparative Example 2 Rotary Shaft 1 with Seal Function of FIG. 8
In the same manner as in No. 11, a seal made of urethane foam was attached to the stainless steel shaft to obtain a seal sliding member of Comparative Example 2.

[Evaluation of Characteristics] Using the seal sliding members for the rotating shaft of Examples 6 and 7 and Comparative Example 2, an experiment was conducted to evaluate the presence or absence of toner leakage. As shown in FIG. 6, an evaluator 21 used in this experiment has a cylindrical housing 22.
Seal sliding members 24 for the rotating shaft
And the lip portion 25 of the seal sliding member 24 is brought into contact with both ends 23 of the housing 22. A motor 26 is connected to the seal sliding member 24, and the housing 22 is filled with toner. The evaluator 21 was operated for 1000 hours, and the presence or absence of toner leakage was examined. The results are shown in Table 2 below.

[0038]

[Table 2]

As shown in Table 2 above, the seal sliding members for the rotating shafts of Examples 6 and 7 and Comparative Example 2 did not cause toner leakage and were not integrated. It was confirmed that it had the same sealing function and bearing function as the moving member. Further, it can be seen that the seal sliding members of Examples 6 and 7 can reduce the number of parts and are superior in productivity and economical efficiency as compared with the seal sliding member of Comparative Example 2.

[0040]

As described above, according to the resin composition for a seal sliding member of the present invention and the seal sliding member using the same, the same bearing as a conventional bearing having a sealing function using a rubber seal or an O-ring is used. It has a bearing function and a sealing function, and has a rotating shaft function and a sealing function equivalent to a conventional rotating shaft with a sealing function using a sealing part. Furthermore, cost reduction and production by reducing the number of parts Performance can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a seal sliding member according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view showing a seal sliding member according to a second embodiment of the present invention.

FIG. 3 is a schematic sectional view showing a seal sliding member according to a third embodiment of the present invention.

FIG. 4 is a schematic sectional view showing a seal sliding member according to a fourth embodiment of the present invention.

FIG. 5 is a schematic sectional view showing an evaluator for evaluating the toner sealing property of the seal sliding member for a bearing according to the present invention.

FIG. 6 is a schematic cross-sectional view showing an evaluator for evaluating the toner sealing property of the rotary shaft seal sliding member according to the present invention.

FIG. 7 is a schematic sectional view showing a conventional bearing with a sealing function.

FIG. 8 is a schematic sectional view showing a conventional rotary shaft with a sealing function.

[Explanation of symbols]

 1, 4, 7 ... seal sliding member 2, 5, 8 ... bearing part 3, 6, 9 ... lip part 10 ... convex ridge part 11 ... seal sliding member 12 ...・ Shaft part 13 ・ ・ ・ Lip part 14 ・ ・ ・ Housing 15, 21 ・ ・ ・ Evaluator 16,22 ・ ・ ・ Housing 17, 24 ・ ・ ・ Seal sliding member 18 ・ ・ ・ Rotating shaft 19, 26 ・ ・・ Motor 20 ・ ・ ・ Stirring screw 23 ・ ・ ・ End 25 ・ ・ ・ Lip

Claims (5)

[Claims] 1. A resin composition for a seal sliding member in which grease is dispersed and contained in a thermoplastic elastomer. 2. The grease content is at least 2% by weight.
The resin composition for a seal sliding member according to claim 1, which is 0% by weight or less. 3. The resin composition for a seal sliding member according to claim 1, wherein the grease comprises a hydrocarbon oil as a base oil and lithium stearate as a thickener. 4. The method according to claim 1, wherein the thermoplastic elastomer is JIS-
4. The resin composition for a seal sliding member according to claim 1, which has an A hardness of 80 or more and 90 or less. 5. The seal according to claim 1, wherein one of the shaft portion and the bearing portion, and an annular lip portion for preventing powder foreign matter from entering a sliding portion thereof. A seal sliding member integrally formed of a resin composition for a sliding member.