阅读说明：本技术 一种半导电发泡转印辊及其制造方法 (Semi-conductive foaming transfer roller and manufacturing method thereof ) 是由 李绍昌 于 2019-08-21 设计创作，主要内容包括：本发明提供了一种半导电发泡转印辊,该转印辊的发泡套管由以下重量百分比的组分所组成：NBR橡胶96-96.2％；发泡助剂0.5-0.7％；填充剂1.9-2.1％；发泡剂0.3-0.7％；促进剂0.4-0.8％；硫磺0.1-0.3％；其中,NBR橡胶中丙烯腈含量为40％,门尼黏度为50。本发明还提供了一种半导电发泡转印辊的制备方法。本发明相较于现有技术可以有效地解决转印辊在高温高湿(60℃、95％RH)环境中放置三天后的外径收缩问题。(The invention provides a semi-conductive foaming transfer roller, wherein a foaming sleeve of the transfer roller consists of the following components in percentage by weight: 96-96.2% of NBR rubber; 0.5 to 0.7 percent of foaming auxiliary agent; 1.9 to 2.1 percent of filling agent; 0.3 to 0.7 percent of foaming agent; 0.4 to 0.8 percent of accelerant; 0.1 to 0.3 percent of sulfur; wherein, the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50. The invention also provides a preparation method of the semiconductive foaming transfer roller. Compared with the prior art, the invention can effectively solve the problem of the shrinkage of the outer diameter of the transfer roller after the transfer roller is placed in a high-temperature and high-humidity (60 ℃ and 95% RH) environment for three days.)

1. A semiconductive foaming transfer roller is characterized in that a foaming sleeve of the transfer roller is composed of the following components in percentage by weight:

wherein the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

2. The semiconducting foam transfer roller of claim 1, wherein the foam sleeve of the transfer roller is composed of the following components in weight percent: 96% of NBR rubber; 0.7 percent of foaming auxiliary agent; 1.9% of a filler; 0.7 percent of foaming agent; 0.4 percent of accelerant; 0.3 percent of sulfur; wherein the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

3. The semiconducting foam transfer roller of claim 1, wherein the foam sleeve of the transfer roller is composed of the following components in weight percent: 96.1% of NBR rubber; 0.6 percent of foaming auxiliary agent; 2% of a filler; 0.6 percent of foaming agent; 0.6 percent of accelerant; 0.1 percent of sulfur; wherein the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

4. The semiconducting foam transfer roller of claim 1, wherein the foam sleeve of the transfer roller is composed of the following components in weight percent: 96.2% of NBR rubber; 0.5 percent of foaming auxiliary agent; 2.1% of a filler; 0.3 percent of foaming agent; 0.8 percent of accelerant; 0.1 percent of sulfur; wherein the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

5. A preparation method of a semiconductive foaming transfer roller is characterized by comprising the following preparation steps:

1) the rubber extruder extrudes the foaming sleeve in a continuous extrusion mode;

2) microwave curing the foaming sleeve, wherein the temperature of the microwave section is controlled to be 150-170 ℃, and the temperature of the hot air section is controlled to be 190-210 ℃;

3) cutting off the sleeve and embedding the shaft core;

4) the transfer roller is formed after grinding.

6. The method for manufacturing a semiconductive foam transfer roller according to claim 5, wherein in the step 2), the temperature of the microwave section is controlled to be 160 ℃.

7. The method according to claim 5, wherein in the step 2), a first hot air segment and a second hot air segment are provided, and the temperature of the first hot air segment is controlled to be 210 ℃ and the temperature of the second hot air segment is controlled to be 190 ℃.

Technical Field

The invention relates to the field of transfer rollers, in particular to a semiconductive foaming transfer roller and a manufacturing method thereof.

Background

The transfer roller of a laser printer or a copier is capable of maintaining or hardly changing the outer diameter dimension of the conductive material for a long period of time and is not changed with the change of the environmental temperature or humidity in addition to the requirements for the stability of the hardness and the resistance of the transfer roller itself in order to achieve a stable transfer effect.

The existing extrusion foaming technology can realize stable correspondence of the parameters at normal temperature corresponding to products with the hardness of 25-60 ℃.

In order to obtain the required hardness and resistance of the transfer roller and to maintain stable dimensions, many attempts have been made to form the transfer roller by coating a high-resistance 10 Ω 10 · cm layer on the outside of a low-resistance 10 Ω 4 · cm layer or a high-resistance 10 Ω 10 · cm resin layer on the outside of a low-resistance 10 Ω 4 · cm layer. Some manufacturers have made various attempts to formulate materials, but the problem of shrinkage of the outer diameter after three days of storage, particularly at high temperature and humidity (60 ℃, 95% RH), is not well improved.

Disclosure of Invention

In view of this, the present invention provides a semiconductive foam transfer roller and a method for manufacturing the same, which can effectively solve the problem of the shrinkage of the outer diameter of the transfer roller after being left in a high-temperature and high-humidity (60 ℃, 95% RH) environment for three days.

To this end, in one aspect, the present invention provides a semiconductive foam transfer roller, the foam sleeve of which is composed of the following components in percentage by weight:

wherein, the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

Further, the foaming sleeve of the transfer roller consists of the following components in percentage by weight: 96% of NBR rubber; 0.7 percent of foaming auxiliary agent; 1.9% of a filler; 0.7 percent of foaming agent; 0.4 percent of accelerant; 0.3 percent of sulfur; wherein, the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

Further, the foaming sleeve of the transfer roller consists of the following components in percentage by weight: 96.1% of NBR rubber; 0.6 percent of foaming auxiliary agent; 2% of a filler; 0.6 percent of foaming agent; 0.6 percent of accelerant; 0.1 percent of sulfur; wherein, the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

Further, the foaming sleeve of the transfer roller consists of the following components in percentage by weight: 96.2% of NBR rubber; 0.5 percent of foaming auxiliary agent; 2.1% of a filler; 0.3 percent of foaming agent; 0.8 percent of accelerant; 0.1 percent of sulfur; wherein, the NBR rubber has an acrylonitrile content of 40% and a Mooney viscosity of 50.

In another aspect, the present invention provides a method for preparing a semiconductive foam transfer roller, comprising the steps of:

1) the rubber extruder extrudes the foaming sleeve in a continuous extrusion mode;

2) the microwave vulcanization foaming sleeve is characterized in that the temperature of a microwave section is controlled to be 150-170 ℃, and the temperature of a hot air section is controlled to be 190-210 ℃;

3) cutting off the sleeve and embedding the shaft core;

4) the transfer roller is formed after grinding.

Further, in the step 2), the temperature of the microwave band is controlled to be 160 ℃.

Further, in the step 2), a first hot air section and a second hot air section are provided, wherein the temperature of the first hot air section is controlled to be 210 ℃, and the temperature of the second hot air section is controlled to be 190 ℃.

Heretofore, a foaming tube is prepared by adding a foaming agent (OBSH), an auxiliary agent, an accelerator and a vulcanizing agent into a mixture of acrylonitrile-butadiene-acrylonitrile (NBR), ethylene-propylene-diene monomer (EPDM) and Epichlorohydrin (ECO) singly or together, mixing, and then extruding and foaming. Foaming means 1) and extruding by an extruder, and foaming by a vulcanizing oven or a vulcanizing tank, so that the efficiency is low, and the method is suitable for small-batch production. 2) Continuous extrusion, microwave vulcanization foaming, high extrusion efficiency, stable performance and larger 1-time investment. In any of the foaming techniques, the transfer roller product is obtained after the foaming process, the vulcanization process, the cutting process, the insertion process, and the grinding process.

The transfer roller produced by the process has countless single-bubble and continuous-bubble foaming bodies similar to rubber bubbles, and when the product is placed in a high-temperature high-humidity (60 ℃ and 95% RH) environment chamber for a placing test, the bubbles expand under heat, so the experimental process of placing the product in the high-temperature high-humidity (60 ℃ and 95% RH) environment chamber, namely the process of expanding the transfer roller under heat.

The cross-linking reaction after the vulcanization of the rubber ensures that the rubber has different tensile strength, different tensile strength and different expansion degrees after being heated. The wall thickness of each foam is different, and the expansion of the foam is also affected. In addition, the different ratios of the single bubbles to the continuous bubbles also have an effect on the thermal expansion results. The smaller the change in thermal expansion, the less the change in thermal expansion relative to when left heated.

Here, in order to solve the problem of expansion change after heat exposure, countermeasures have been taken in three aspects of tensile strength of the material, thickness and uniformity of the wall thickness, and ratio of single bubbles and continuous bubbles. So that the external diameter shrinkage after the placement is controlled within the specification range.

The proposal solves the problem of the shrinkage of the outer diameter of the transfer roller after being placed for three days under high temperature and high humidity (60 ℃ and 95 percent RH). The transfer roller is foamed and then has numerous single bubbles and continuous bubbles of rubber, and these bubbles have different wall thicknesses and different tensile strengths, and thus have different degrees of expansion after being heated. After the rubber is foamed, the change degree of the rubber is different due to different quantities of continuous bubbles and single bubbles and the mixed connection phenomenon of the continuous bubbles and the single bubbles, and in addition, due to different wall thicknesses, the heat conduction conditions and the change degree of the rubber are different after being heated, so that the transfer roller with a more stable size can be obtained after being placed in a high-temperature and high-humidity environment for 3 days.

The technical scheme provided by the invention is mainly innovated from two aspects:

1) selected aspects of the material: the Mooney viscosity of the rubber determines the tensile strength of the foaming material; the higher the Mooney viscosity of the rubber, the higher the relative molecular mass, the larger the force acting between molecules, and the better the tensile strength. The higher the acrylonitrile content, the more polar the molecules, the higher the intermolecular forces, and the better the tensile strength will be. However, when the Mooney viscosity is too high, it is difficult to control the cell diameter of the transfer roller, and when the content of acrylonitrile is too high, the precipitation of the transfer roller is disadvantageously caused; for the foaming material with high acrylonitrile content and relatively high Mooney viscosity, the foamed product has good tensile strength, the wall of the foam hole is not easy to deform under the action of air pressure difference, and the outer diameter does not change greatly before and after high-temperature and high-humidity placement, so that the shrinkage after placement is also small;

2) the improvement aspect of the process is as follows: in order to obtain a foaming pipe with thicker and uniform wall thickness, and simultaneously, a product with higher continuous foaming rate and less single foaming rate, the control of the technological parameters of extrusion vulcanization is also an indispensable link. The thicker the wall thickness, the greater the resistance to changes in the cells caused by the hot air within the cells after exposure to heat. When the foaming pipe has a large continuous foaming ratio, the hot air has good fluidity, so that the hot air is not held in the rubber ball due to single foam, is preheated and expanded, and is slowly leaked to cause large shrinkage after cooling. In order to improve efficiency, microwave continuous foaming is a relatively efficient and stable foaming process, foaming temperatures of a microwave section and a hot air section are controlled through repeated tests and improvements, and good improvement effects are obtained for wall thickness improvement and single-bubble and continuous-bubble ratio control means.

Therefore, compared with the prior art, the invention mainly has the following advantages:

1) as one of the test indexes of the 0A industry, the outer diameter of a foam tube (transfer roller) shrinks to less than 0.05mm after being placed at high temperature and high humidity (60 ℃, 95% RH) for 3 days;

2) according to the test improvement scheme, after a foaming tube (transfer roller) product with a normal foaming process and a formula is placed for 3 days at high temperature and high humidity, the test outer diameter shrinkage is 0.08-0.15 mm; through repeated tests and process improvement of the formula, the outer diameter shrinkage of the product is below 0.03 mm;

3) from our experimental results, our improvement is effective in improving the problem of shrinkage of the outer diameter of the foam tube.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:

fig. 1 is a comparison graph of outer diameter variation curves before and after placing of a semiconductive foam transfer roller according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.