JP3971926B2 - Manufacturing method of rubber roller - Google Patents

Description

表１より、実施例の方が工程数が多いにも関わらず、注入の合計時間は３分近く短いことが分る。
【００５５】
【発明の効果】
以上の説明に加え、本発明によれば、以下に記載するような具体的効果が得られる。
【００５６】
先ず、熱硬化性液状ゴムの硬化を待たずに、注入ノズルを外すことができ、ノズルタッチを含めた注入に要する時間が短縮することができるため、ゴムローラを製造する装置全体の稼働率が向上する。
【００５７】
また、熱硬化性液状ゴムを注入する際に、通気孔を通じてエアーが逃げ、また、通気孔に熱硬化性液状ゴムが達し僅かに進入すると、断面積が小さいためすぐに硬化し、これが栓の役目を果たすため、注入後すぐに成形金型を反転しても、熱硬化性液状ゴムが垂れることがない。
【００５８】
更に、オーバーフローによるゴム廃棄材が無くなるので、材料コストを低減できる。
【図面の簡単な説明】
【図１】本発明の成形金型を説明するための模式的断面図である。
【図２】従来の成形金型を説明するための模式的断面図である。
【図３】本発明における上駒を説明するための模式的斜視図である。
【符号の説明】
１ 上駒
１ｂ 通気孔（溝）
１ｃ 穴
２ 金型本体
３ 下駒
３ａ 注入口
４ 芯金
５ａ 注入ノズル
５ｂ 注入ノズル
６ ノズルタッチ板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding die and a method for manufacturing a rubber roller using a thermosetting liquid rubber.
[0002]
[Prior art]
As a method of manufacturing a rubber roller using thermosetting liquid rubber, the injection nozzle is pressed (nozzle touch) directly or via a nozzle touch plate to the lower piece fitted to the lower part of the cylindrical mold body, There is a method in which a thermosetting liquid rubber is injected from an injection port provided in a piece and cured to form a rubber layer.
[0003]
Thus, by arranging the injection port on the lower side and injecting the thermosetting liquid rubber from the lower side of the molding die, it is possible to suppress the generation of bubbles in the thermosetting liquid rubber.
[0004]
However, in this method, in order to avoid dripping uncured thermosetting liquid rubber from the injection port, it is necessary to press the injection nozzle until the thermosetting liquid rubber near the injection port is cured. In some cases, the time required for injecting the thermosetting liquid rubber including the nozzle touch becomes long.
[0005]
In order to prevent the thermosetting liquid rubber from drooping even if the injection nozzle is removed immediately after the injection of the thermosetting liquid rubber, it is possible to provide a dripping prevention mechanism on the lower part of the mold. It is described in. However, in the method described in the publication, the mold structure may be complicated.
[0006]
[Problems to be solved by the invention]
As described above, in the method in which the injection nozzle is pressed against the lower piece fitted to the lower part of the mold directly or via the nozzle touch plate and the thermosetting liquid rubber is injected from the injection nozzle, the heat near the injection port is obtained. The injection nozzle cannot be released until the curable liquid rubber is cured, and the productivity may be insufficient.
[0007]
Further, if a dripping prevention mechanism is provided at the lower part of the mold, the manufacturing cost of the mold increases, and as a result, the manufacturing cost of the rubber roller may increase.
[0008]
In view of the above situation, the present invention aims to reduce the time required for injection of thermosetting liquid rubber including nozzle touch by removing the injection nozzle without waiting for curing of the thermosetting liquid rubber. To do.
[0009]
[Means for Solving the Problems]
According to the present invention for achieving the above object, a step of arranging a cored bar in a hollow cylindrical mold body,
Each cross-sectional area is 0.5 mm ² or less, and the sum total of the cross-sectional areas is 1.5 mm ² or less. The upper piece provided with a plurality of fine ventilation holes and the lower part provided with the injection port. A step of fitting a piece into the mold body and assembling a molding mold;
Connecting an injection nozzle to the injection port;
Injecting the thermosetting liquid rubber from the injection nozzle connected to the injection port so that the inside of the molding die is filled;
Immediately after the end of the injection step, the step of turning the molding die upside down with the injection nozzle connected to the injection port;
Removing the injection nozzle from the injection port with the molding die turned upside down;
Reversing the top and bottom of the removed injection nozzle to return to the initial arrangement;
A method for producing a rubber roller is provided.
[0011]
The present invention solves the problem by inverting the upper and lower sides of the molding die immediately after the injection of the thermosetting liquid rubber is completed.
[0012]
That is, when the injection of the thermosetting liquid rubber is completed, the molding die is turned upside down with the injection nozzle connected. After inversion, since the injection part is located above the mold, the uncured thermosetting liquid rubber will not leak even if the injection nozzle is removed.
[0013]
The removed injection nozzle is immediately connected to the injection port of the next molding die to inject thermosetting liquid rubber.
[0014]
In addition, since a vent is formed in the upper piece of the molding die, air inside the molding die is exhausted to the outside through the vent as the thermosetting liquid rubber is injected. And when the thermosetting liquid rubber reaches the vent hole and enters slightly, the vent hole is fine and the cross-sectional area of the vent hole is small, so that the thermosetting liquid rubber is immediately cured in and / or near the vent hole, Serves as a vent plug. For this reason, even if the mold is turned upside down, the thermosetting liquid rubber is prevented from leaking from the vent hole.
[0015]
Therefore, the thermosetting liquid rubber is injected from the injection nozzle connected to the injection port of the lower piece, and when the injection is completed, the molding die is immediately turned upside down while the injection nozzle is connected, and after the molding die is inverted, thermosetting is performed. By removing the connected injection nozzle without waiting for the curing of the curable liquid rubber, the time required for the injection of the thermosetting liquid rubber including the nozzle touch can be shortened.
[0016]
As a result, since the time required for injecting the thermosetting liquid rubber including the nozzle touch can be shortened without complicating the structure of the molding die, the rubber roller can be manufactured with good productivity and low cost.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
The vent hole formed in the upper piece is made fine enough that the thermosetting liquid rubber does not leak even if the molding die is turned upside down immediately after the injection of the thermosetting liquid rubber.
[0018]
Specifically, the cross-sectional area of the air hole is preferably 0.5 mm ² or less.
[0019]
On the other hand, in order to sufficiently exhaust the air inside the molding die, the cross-sectional area of the vent is preferably 0.05 mm ² or more.
[0020]
The upper piece is preferably provided with a plurality of vent holes. In this case, since the cross-sectional area per vent hole can be reduced, the liquid leakage of the thermosetting liquid rubber can be more reliably suppressed when the molding die is turned upside down. Further, the air inside the molding die can be exhausted evenly.
[0021]
From the above viewpoint, when a plurality of vent holes are provided, it is preferable that any cross-sectional area of the vent holes is 0.05 mm ² or more and 0.5 mm ² or less. Moreover, it is preferable that the sum total of the cross-sectional area of several ventilation hole is 1.5 mm < ² > or less.
[0022]
Further, a groove is formed in the fitting portion of the upper piece with the mold body, and it is preferable that the groove is made into a vent hole by fitting the upper piece and the mold body. In this case, if a cured product of the thermosetting liquid rubber remains in the vent hole, it can be easily removed.
[0023]
Furthermore, the connection of the injection nozzle to the injection port may be either directly or via an attachment.
[0024]
In addition, when the thermosetting liquid rubber is injected by arranging the injection port on the lower side and injecting the thermosetting liquid rubber from the lower side of the molding die, bubbles are generated in the thermosetting liquid rubber. This can be suppressed.
[0025]
Further, by filling all the spaces in the molding die with the thermosetting liquid rubber, it is possible to suppress the generation of bubbles in the thermosetting liquid rubber when the molding die is turned upside down.
[0026]
Furthermore, the molding die is preferably preheated to the curing temperature of the thermosetting liquid rubber prior to the injection of the thermosetting liquid rubber.
[0027]
When the molding die is heated to the curing temperature of the thermosetting liquid rubber in advance and an injection nozzle is connected to the injection port of the lower piece of the molding die to inject the thermosetting liquid rubber, Alternatively, since the thermosetting liquid rubber in the vicinity is more fully cured, the liquid leakage of the thermosetting liquid rubber can be more reliably prevented when the molding die is turned upside down.
[0028]
As the thermosetting liquid rubber injected into the molding die, thermosetting liquid silicone rubber, thermosetting liquid urethane rubber or the like is used.
[0029]
As the thermosetting liquid silicone rubber, for example, a two-component mixed type in which a solution A containing a main component of silicone rubber and a solution B in which a curing agent is mixed can be used. As the main component of the silicone rubber, linear dimethylpolysiloxane and the like are preferable, and the terminal and / or side chain may contain an alkyl group such as a vinyl group or an ethyl group, an aryl group such as a phenyl group, or the like. Moreover, in order to improve heat insulation and intensity | strength, fillers, such as a silica and a bengara, and electrically conductive materials, such as carbon black, can be mix | blended in order to improve electroconductivity.
[0030]
As the thermosetting liquid urethane rubber, for example, a liquid urethane prepolymer obtained from polyisocyanate and polymer polyol can be used.
[0031]
Specific examples of the polyisocyanate include diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), and the like.
[0032]
Examples of the polymer polyol include polyester polyols, polyether polyols, caprolactone ester polyols, polycarbonate ester polyols, and silicone polyols. These weight average molecular weights are usually 500 or more and 5000 or less.
[0033]
More specifically, polyethylene adipate (PEA), polybutylene adipate (PBA), polyhexylene adipate, a copolymer of ethylene adipate and butylene adipate, and the like can be used as the polyester polyol. Polycaprolactone, polyoxytetramethylene glycol, polyoxypropylene glycol and the like can be used.
[0034]
Moreover, a chain extender, a crosslinking agent, a catalyst, etc. can also be mixed with a liquid urethane prepolymer as needed.
[0035]
【Example】
As a rubber roller manufacturing method of the present invention, a manufacturing example of a pressure roller of an electrophotographic copying apparatus will be described with reference to the drawings. However, the present invention is not limited to the following embodiments. Unless otherwise specified, commercially available high-purity products were used as reagents.
[0036]
(Example)
The molding die (FIG. 1) used in the examples has a die body 2 having an inner shape of 21 mm in inner diameter and a cylindrical shape of 240 mm in length, and an upper piece 1 fitted on the die body 2. It is composed of three parts including a lower piece 3 fitted under the mold body 2. An injection nozzle 5 a is connected to the lower piece 3, and each injection nozzle 5 a is communicated with the mold body 2 through an injection port 3 a having a diameter of 1.5 mm.
[0037]
A vent hole 1b is formed in the fitting portion between the mold body and the upper piece. In order to form the ventilation hole 1b, as shown in FIG. 3, the upper piece 1 has a width of 1.5 mm and a height of 0 at four locations from the abutment portion of the mold body and the upper piece to the fitting portion. A 2 mm groove 1b is formed. In this case, the cross-sectional area of one ventilation hole is 0.3 mm ² and the total cross-sectional area is 1.2 mm ² .
[0038]
In addition, a core metal 4 is disposed inside the mold body 2.
[0039]
As the thermosetting liquid rubber, a two-component mixed type thermosetting liquid silicone rubber mixed with silica and bengara and having a viscosity of 0.5 Pa · s was used.
[0040]
First, prior to the injection of the thermosetting liquid silicone rubber, the mold is heated in advance to the thermosetting liquid silicone rubber curing temperature of 140 ° C., and then directly injected into the inlet of the lower piece fitted in the lower part of the mold. The nozzle was connected. Injection of thermosetting liquid silicone rubber was started from this nozzle, and an amount of thermosetting liquid silicone rubber necessary for completely filling the inside of the mold body was injected. Simultaneously with the end of injection, the molding die was turned upside down with the injection nozzle connected.
[0041]
At this time, the thermosetting liquid silicone rubber in and near the vent hole was cured, and no liquid leakage occurred. Also, no bubbles were generated in the thermosetting liquid silicone rubber when the thermosetting liquid silicone rubber was injected or when the molding die was reversed.
[0042]
After the reversal of the molding die, the injection nozzle was separated from the molding die, and the injection nozzle was turned upside down to return to the initial arrangement. Further, the obtained rubber roller was released from the molding die by removing the upper piece of the molding die. When a cured product of the thermosetting liquid silicone rubber remained in the vent hole, it was removed with good workability.
[0043]
In addition, the time required for each process was measured, and the time required from the connection of the injection nozzle to the nozzle inversion was taken as the total time for injection.
[0044]
(Comparative example)
As a comparative example, a method is shown in which, after injecting a thermosetting liquid silicone rubber, the thermosetting liquid silicone rubber is cured without turning the mold upside down, and then the injection nozzle is removed.
[0045]
The molding die (FIG. 2) used in the comparative example has a cylindrical mold body 2 having an inner diameter of 21 mm and a length of 240 mm, and an upper piece fitted on the mold main body 2 as in the embodiment. 1 and a lower piece 3 fitted under the mold main body 2.
[0046]
Unlike the embodiment, the upper piece 1 has four holes 1c for releasing the thermosetting liquid silicone rubber for overflow. The hole 1c is narrower on the roller side and becomes thicker toward the top. The narrowest part is a hole of φ1 mm.
[0047]
In addition, the lower piece 3 is formed with an injection port 3a to which a nozzle touch plate 6 is connected. The injection nozzle 5 b is connected to the nozzle touch plate 6.
[0048]
From this injection nozzle, injection of the same thermosetting liquid silicone rubber as that used in the examples was started, and an amount of thermosetting liquid silicone rubber necessary to completely fill the inside of the mold body was injected. After completion of the injection, the thermosetting liquid silicone rubber in the vicinity of the injection port was cured in a state where the injection nozzle was in contact with the molding die not being turned upside down. At this point, the thermosetting liquid silicone rubber did not leak and the injection nozzle was removed.
[0049]
As in the case of the example, the time required for each step was measured, and the time required from connecting the injection nozzle to the molding die until the injection nozzle was removed was defined as the total injection time.
[0050]
(Total time of injection)
In the examples, the total injection time is the time required to connect the nozzle, the time required to inject the thermosetting liquid silicone rubber, the time required to turn the molding die upside down, and the time required to remove the nozzle. , And the total time required to reverse the top and bottom of the nozzle to return to the initial arrangement.
[0051]
On the other hand, in the comparative example, the total injection time is the time required to connect the nozzle, the time required to inject the thermosetting liquid silicone rubber, the time to keep the nozzle connected (nozzle touch time), the nozzle This is the total of the time required for removal.
[0052]
The nozzle touch time is equivalent to the time required for the thermosetting liquid silicone rubber in the vicinity of the injection port to cure.
[0053]
The measurement results of the above time are shown in Table 1.
[0054]
[Table 1]

From Table 1, it can be seen that the total injection time is nearly 3 minutes shorter, although the embodiment has more steps.
[0055]
【The invention's effect】
In addition to the above description, according to the present invention, specific effects as described below can be obtained.
[0056]
First, the injection nozzle can be removed without waiting for the thermosetting liquid rubber to cure, and the time required for injection including nozzle touch can be shortened, improving the operating rate of the entire apparatus for manufacturing rubber rollers. To do.
[0057]
In addition, when the thermosetting liquid rubber is injected, air escapes through the vent hole. In order to fulfill the role, the thermosetting liquid rubber does not sag even if the molding die is reversed immediately after injection.
[0058]
Furthermore, since there is no rubber waste material due to overflow, the material cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view for explaining a molding die of the present invention.
FIG. 2 is a schematic cross-sectional view for explaining a conventional molding die.
FIG. 3 is a schematic perspective view for explaining an upper piece in the present invention.
[Explanation of symbols]
1 Upper piece 1b Vent (groove)
1c Hole 2 Mold body 3 Lower piece 3a Inlet 4 Core metal 5a Injection nozzle 5b Injection nozzle 6 Nozzle touch plate

Claims (2)

Placing the cored bar in the hollow cylindrical mold body;
Each cross-sectional area is 0.5 mm ² or less, and the sum total of the cross-sectional areas is 1.5 mm ² or less . The upper piece provided with a plurality of fine ventilation holes and the lower part provided with the injection port. A step of fitting a piece into the mold body and assembling a molding mold;
Connecting an injection nozzle to the injection port;
Injecting the thermosetting liquid rubber from the injection nozzle connected to the injection port so that the inside of the molding die is filled;
Immediately after the end of the injection step, the step of turning the molding die upside down with the injection nozzle connected to the injection port;
Removing the injection nozzle from the injection port with the molding die turned upside down;
A method of manufacturing a rubber roller, comprising the step of inverting the top and bottom of the removed injection nozzle to return to the initial arrangement. Assembled the molding die prior to injection of the thermosetting liquid rubber, the manufacturing method of the rubber roller according to claim 1, characterized in that it is pre-heated to the curing temperature of the thermosetting liquid rubber.

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