JPH0322628B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a fixing roll for heating and fusing an image transferred to paper in an electrophotographic copying machine, a printer, etc.
Addition-type liquid silicone rubber in which silicone rubber containing SiH group-containing siloxane as a crosslinking agent and a platinum-based compound as a catalyst for promoting the reaction between vinyl groups and SiH groups is adhered to a core metal via a primer. related to manufactured fixing rolls. Conventionally, the silicone rubber used in the above-mentioned fixing roll generally contains dry fine powder silica as a reinforcing filler in order to improve strength, heat resistance, and oil resistance. This has disadvantages in that it causes the so-called offset phenomenon in which copying paper adheres to the copy paper, and it also causes the copy paper to wrap around. In view of the above points, an object of the present invention is to provide a fixing roll that rationally contains a reinforcing filler in silicone rubber and has excellent strength, heat resistance, and oil resistance as well as mold release properties. shall be. In order to achieve the above object, the present invention provides the fixing roll made of addition-type liquid silicone rubber described above, in which dry fine powder silica and wet fine powder silica are added to the silicone rubber in a weight ratio of 20 to 80 wt%. It is characterized by containing a filler mixed in a state. That is, based on various experiments, using wet-processed finely powdered silica as a filler alone has excellent mold release properties but lacks heat resistance and oil resistance, but when mixed with dry-processed finely divided silica in a predetermined ratio as described above We have discovered that we can take advantage of mutual advantages by using these rolls, and as a result, we are able to provide a fixing roll that not only has excellent strength, heat resistance, and oil resistance, but also has excellent mold releasability. Durability can be improved without causing damage to the silicone rubber, and moreover, it has excellent mold releasability, making it possible to avoid occurrence of offset phenomenon and wrapping of copy paper. The vinyl group-containing siloxane used in the present invention is represented by the general formula ViR ₂ SiO(R ₂ SiO)nSiR ₂ Vi. In the formula, R is a C ₁ to ₈ hydrocarbon group;
More than 90 mol% is CH ₃ − group, and Vi is CH ₂ =CH
- group, and the viscosity at 25℃ is 500~
It is 30,000 centistokes. As SiH group-containing siloxane, 3
It is a dimethylpolysiloxane having more than 10 SiH groups, and has a viscosity of 10 to 1000 centistokes at 25°C, and has a vinyl group-containing siloxane.
It is blended in an amount that provides 0.9 to 3.0 moles of SiH to the Vi group. The platinum-based compound is a platinum compound used in general addition reactions. Examples of dry fine powder silica with a surface area of 50 m ² /g or more include commercially available Aerosil A300 (manufactured by Nippon Aerosil Co., Ltd.), Tullanox 500 (manufactured by Talco Co., Ltd.),
Aerosil R-972 (manufactured by Nippon Aerosil Co., Ltd.)
etc. In addition, as wet fine powder silica, the surface area is 50m ² /g.
For example, commercially available Nipsil E200 (manufactured by Nippon Silica Kogyo), Nipsil SS-30 (manufactured by Nippon Silica Kogyo),
Zeoseal 1000V (manufactured by Taki Chemical) etc. In addition,
Said Tullanox500, Aerosil R-972 and
Nipsil SS-30 has been subjected to surface hydrophobization treatment. The content of the mixture of dry finely divided silica and wet finely divided silica is preferably 10 to 50 parts by weight based on 100 parts by weight of the mixture of vinyl group-containing siloxane, SiH group-containing siloxane, and platinum compound. If it is less than 10 parts by weight, the strength will decrease;
This is because if the amount exceeds 1 part by weight, the viscosity becomes too high and molding becomes difficult. In order to obtain suitable strength and viscosity, the amount is preferably 20 to 45 parts by weight. Furthermore, in addition to the above-mentioned components, quartz powder with a surface area of 50 m ² /g or less, which is used for conventional fixing rolls,
For example, commercially available Min-U-Sil (manufactured by Philadelphia Quartz Co., Ltd.) with a size of 5 microns, ImSil A-10
(manufactured by Illinois Mineral Co.), crystallite (manufactured by Tatsumori Industries), diatomaceous earth, etc. may also be used. Also,
For example, color pigments such as iron oxide, titanium oxide, and zinc oxide, heat-resistant additives such as cerium oxide, aluminum oxide, calcium carbonate, and zinc carbonate, and
A plasticizer such as dimethyl silicone oil may also be used. Embodiments of the present invention will be described below with reference to the drawings. First, the manufacturing process of the fixing roll will be explained. (1) First cleaning step (see Figure 1) Using a cleaning machine 4 equipped with a hot bath 1, an ultrasonic bath 2, and a steam bath 3, a core bar 5 made of aluminum or the like is attached to a carrier 6, and the cleaning process is performed in order. Then, cutting oil and the like adhering to the surface of the core metal 5 are removed. In the figure, 3a indicates a cooling pipe. (2) Core metal surface treatment process (see Figure 2) The core metal 5 after the cleaning treatment is mounted on the rotary table 7, and the surface of the core metal 5 is activated by supplying a chemical solution through the nozzle 8. After that, a blasting machine ( (not shown) to roughen the surface of the core metal 5. (3) Second cleaning step (see Figure 3) Using the cleaning machine 4, an ultrasonic bath 2 and a steam bath 3
This removes contaminants that have adhered during the above-mentioned surface treatment. (4) Primer application step (see Fig. 4) The core metal 5 is supported by rotating jigs 9, 9, and the rotating core metal 5 is coated with the primer of the example described later to a thickness of 0.5 to 20 μm using a spray device 10. Apply with water. (5) Air-drying process (see Figure 5) The core metal 5a coated with the primer is mounted on the support stand 11 in an upright position, and dried at room temperature by blowing air in the drying chamber 12 for 15 to 60 minutes. 6 Pre-bake process (see Figure 6) After the air-drying process, the core bar 5a is placed in the hot-air drying oven 13.
Heat the primer and harden it by blowing hot air at 100 to 180℃ for 15 to 60 minutes. 7 Injection molding process (see Figure 7) The core metal 5a with hardened primer is
The fixed mold 14 heated to ~200°C is fixedly supported, and the movable mold 15 is attached to it, and liquid silicone rubber is injected into it through the nozzle 16 for 30 seconds to 10 seconds until the silicone rubber hardens by addition curing. Leave it as it is for a minute. (8) Aging process (see Figure 8) After being left to stand, the obtained roll 5b is placed in a thermostatic oven 17 and heated at 100 to 250°C for 60 to 300 minutes to perform aging. It not only makes the curing of the rubber material that has completed the primary curing more complete, but also improves the physical properties against permanent compressive strain and the like. (9) Polishing process (see Fig. 9) After aging, the roll 5b is run through a polishing machine 18 to cut the outer periphery of the silicone rubber layer of the roll 5b, finishing it in an outer diameter close to the final outer diameter. Note that this polishing step may be omitted if the outer diameter of the roll 5b after aging is close to the final outer diameter. (10) Oil dipping process Attach the roll 5b to the carrier 6a and
9, and is incorporated into a copying machine and immersed in the same silicone oil that is applied during fixing, while being fluidized by a stirrer 20, and during copying, as the silicone oil is applied, the resulting material is impregnated with silicone oil. The silicone rubber is swollen by the roll 5b.
In order to prevent the outer diameter of the roll 5b from changing, the roll 5b is allowed to swell in equilibrium in advance. (11) Polishing step (see FIG. 9) Finally, the same polishing machine 18 as in the polishing step described above is used to cut the outer surface of the roll 5b, thereby obtaining a fixing roll as a product with a predetermined size. Note that if the final outer diameter is guaranteed even after the oil dipping step, this step may be omitted. [Example] Consists of 97 mol% dimethylsiloxane units and 3 mol% methylvinylsiloxane units, and has a viscosity of
It consists of 100 parts by weight of methylvinylpolysiloxane with a temperature of 5,000,000 centistokes (25°C), 35 mol% of methylsiloxane units, 30 mol% of dimethylsiloxane units, and 35 mol% of phenylsiloxane units, and has a silanol content of 0.12 mol/100g. 20 parts by weight of silicone resin, 10 parts by weight of γ-methacryloxypropyltrimethoxysilane, 100 parts by weight of ethyl polysilicate, methylhydrogen polysiloxane with a viscosity of 15 centistokes (30 mol% dimethylsiloxane units, 70 mol% methylhydrogen siloxane units) A primer was prepared by adding 500 parts by weight of toluene and 1000 parts by weight of ethyl acetate to 100 parts by weight of an isopropanol solution of chloroplatinic acid (Pt concentration 10 ^-5 concentration) and 5 parts by weight of tetrapropyl titanate. This primer was applied to an aluminum core (outer diameter 40 mm) to a thickness of 10 μm by spray coating, followed by air drying and a prebaking process at 150° C. for 40 minutes. Next, as an addition-curing liquid silicone rubber,
Dimelpolysiloxane [Me ₂ ViSiO (Me 2 SiO) nSiMe 2 Vi] with a viscosity of 3000 centistokes at 25°C and end-blocking with dimethylvinylsilyl groups [Me 2 ViSiO (Me ₂ SiO) nSiMe ₂ Vi] (Me: methyl group, Vi: vinyl group) Approximately 97% by weight 3 parts by weight of a siloxane containing 6 SiH groups with a viscosity of 13 centistokes at 25°C, 2.0 x 10 ^-5 parts by weight of a platinum compound, 20 parts by weight of dry finely divided silica, 15 parts by weight of wet finely divided silica.
Parts by weight of quartz powder, 50 parts by weight of quartz powder, and 1 part by weight of red iron were thoroughly mixed, and the process was carried out at the following temperature and treatment time to finally form an addition-type liquid silicone rubber with a thickness of 0.5 mm. A silicone rubber fixing roll was obtained.・Injection molding process Mold temperature: 150℃ Standing time: 5 minutes ・Aging process: Temperature: 200℃ Time: 4 hours ・Oil dating process: Temperature: 180℃ Time: 24 hours The silicone oil used has a viscosity of 100 centistokes at 25℃. there was. [Comparative Example 1] A fixing roll was obtained under exactly the same conditions as in the above example except that 15 parts by weight of wet fine powder silica was replaced with dry fine powder silica. [Comparative Example 2] A fixing roll was obtained under exactly the same conditions as in the above example except that 20 parts by weight of dry fine powder silica was replaced with wet fine powder silica. The fixing rolls obtained in the above Examples, Comparative Example 1, and Comparative Example 2 were installed in a silico oil coating type copying machine, and the heating temperature for the fixing roll was adjusted.
When the temperature was controlled to 160°C and copies were made on A4 paper, the following results were obtained. Example: Even after 500,000 copies were made, no rubber damage, offset, or paper wrapping occurred. Comparative Example 1: Rubber failure occurred after 200,000 copies, and offset and copy paper wrapping frequently occurred. Comparative example: Rubber failure occurred after 30,000 sheets. That is, from the above results, the fixing roll of the present invention
Excellent in heat resistance, oil resistance, and mold releasability,
It was clear that good copying could be achieved over a long period of time while avoiding any of the occurrence of rubber breakage, offset phenomena, and wrapping of the copy paper. When the weight ratio of dry fine powder silica (indicated by A in the table) and wet fine powder silica (indicated by B in the table) was changed little by little, the results shown in the table below were obtained.
However, the content of this mixed filler is platinum-based compound
It was set at 35 parts by weight per 100 parts by weight.

[Table] In the above results, when the content of dry fine powder silica was 7 parts by weight and the weight ratio was 20 wt%, some rubber destruction was observed when the number of copies was about 400,000 sheets, but in practical use , it was possible to use even 500,000 sheets. In addition, when the content of dry fine powder silica was 28 parts by weight and the weight ratio was 80 wt%, some offset occurred when the number of copies was about 450,000 sheets.
In practice, it was possible to use more than 500,000 sheets. In addition, 10 parts by weight of dry fine silica and 40 parts by weight of wet fine silica make the weight ratio of dry fine silica 20wt%, and 40 parts by weight of dry fine silica and 40 parts by weight of wet fine silica. silica
The weight ratio of dry fine powder silica is 10 parts by weight.
When the above-mentioned experiment was carried out with 80 wt%, it was possible to make more than 500,000 copies without rubber damage, offset, or wrapping of the copying machine. From the above results, when the absolute content of dry-processed finely powdered silica and wet-processed finely powdered silica is less than 10 parts by weight, the former tends to have lower hardness and rubber breakage during copying, while the latter tends to cause rubber breakage. Offset and wrapping of multiple papers tend to occur easily, so it is preferable that the absolute content of each of the above-mentioned silicas is 10 parts by weight or more. It is clear that silicone rubber should contain a filler mixed with finely divided silica in a weight ratio of 20 to 80 wt%.

[Brief explanation of drawings]

The drawings are explanatory diagrams showing each process for manufacturing the fixing roll of the present invention, in which Fig. 1 shows the first cleaning process, Fig. 2 shows the core metal surface treatment process, and Fig. 3 shows the second cleaning process and the fourth process. The figure shows the primer application process, Figure 5 shows the air drying process, Figure 6 shows the pre-baking process, Figure 7 shows the injection molding process, Figure 8 shows the aging process, Figure 9 shows the polishing process, and Figure 10 shows the oil date process. The ping process is shown.

Claims (1)

[Claims] 1. Vinyl group-containing siloxane, as a crosslinking agent
In an addition type liquid silicone rubber fixing roll in which silicone rubber containing SiH group-containing siloxane and a platinum compound as a catalyst for promoting the reaction between vinyl groups and SiH groups is adhered to a core metal through a primer. , one weight ratio of dry fine powder silica and wet fine powder silica is added to the silicone rubber.
An addition-type liquid silicone rubber fixing roll containing a filler mixed at 20 to 80 wt%. 2 The vinyl group-containing siloxane, the SiH group-containing siloxane as a crosslinking agent, and the vinyl group and SiH
The addition-type liquid silicone rubber fixer according to claim 1, wherein the filler is contained in an amount of 10 to 50 parts by weight per 100 parts by weight of a mixture of platinum-based compounds as a catalyst for promoting reaction with groups. roll.