JP2727078B2 - Semi-insulating resin composition for transfer roller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the Invention [Industrial Application Field] The present invention relates to a semi-insulating resin composition used for a surface coating material of a transfer roller of an electronic copying machine.

[Prior art and its problems] A transfer roller in an electronic copying machine moves by rotation while electrostatically adsorbing and holding a charged toner (developer) on its surface, and conveys it to a photosensitive drum. The electrostatic latent image formed on the rotating surface of the photoreceptor drum (image surface of the formed object due to the point of disappearance of the charge) is electrostatically attracted and transferred to generate a visible image.

Therefore, the surface coating material of the transfer roller must satisfy the following requirements.

(1) semi-insulating enough to electrostatically adsorb the toner; (2) semi-insulating enough to adjust the amount of electrostatically adsorbed toner; (3) gap between the photosensitive drum (4) Abrasion resistance to rolling friction via toner (5) Coating surface has appropriate hardness [Means for Solving the Problems] In view of the above requirements, the present invention provides an appropriate conductivity and secures the stability of the conductivity, durability against rolling friction, and the like, leading to an improvement in performance, Conducting intensive research on issues such as the reduction of resin dripping during coating drying and the reaction curing time during coating film curing leading to improved productivity, and the expansion of the range of electrical conductivity leading to the expansion of applications. As a result, the epoxy compound A thermosetting resin composed of a phenol-formaldehyde resin and a semi-insulating resin of a cationic quaternary ammonium salt copolymerized with an acrylic resin and a tertiary amine having two 2-hydroxyethyl groups in the molecule are mixed. The present inventors have found that a composition having a very characteristic feature that solves the above-mentioned problems can be obtained by selecting the compounding ratio by using the above-described method.

That is, the present invention provides (a) a general formula: (Where l, m and n in the formula are integers of 0 to 2) A thermosetting resin comprising 5 to 30 parts by weight of an epoxy compound represented by the following formula and (b) 70 to 95 parts by weight of a resole-type phenol formaldehyde resin. (C) Acrylic resin copolymerized cationic quaternary ammonium salt which is solid at room temperature and (d) a tertiary amine which is liquid at room temperature and has two 2-hydroxyethyl groups per 100 parts by weight are mixed. (C) a cationic quaternary ammonium salt copolymerized with an acrylic resin in a fixed form at room temperature and (d) two 2-hydroxy groups in a liquid form at room temperature. The mixing ratio R [= (c) / (d)] with the tertiary amine having an ethyl group is
The semi-insulating resin composition preferably has a range of 0.3 to 0.6.

The epoxy compound used in the present invention improves the adhesion between the coating film and the coating film support, and has a conductive property between the resin of the cationic quaternary ammonium salt having a semi-insulating property to be described later as shown in Table 1. A synergistic relationship arises that extends the range of rates. The content ratio of the capoxy compound in the thermosetting resin is 5 to 30.
It is preferable to select the weight%. When the content is 5% by weight or less, the conductivity range is not expanded. However, when the compounding ratio is 5% by weight or more, a synergistic relationship in which the conductivity range is expanded is recognized. Also,
If the blending ratio is 30% by weight or more, resin dripping occurs during coating and drying, making it difficult to form a uniform coating film, and hardening time is prolonged, resulting in poor productivity and weakening of the finished coating film. There are disadvantages such as becoming. When the content is 30% by weight or less, such defects are eliminated, and resin dripping does not occur during coating and drying, so that a uniform coating film can be easily formed, and the curing time becomes an appropriate length, and the cured coating film is uniform. And the strength of the completed coating film can be increased.

Note that there was no synergistic relationship between the other epoxy resins and the semi-insulating resin in expanding the range of conductivity.

The resol-type phenol formaldehyde resin is obtained by reacting phenol alone or a mixture of phenol and other phenols with formaldehyde in the presence of an alkali catalyst, and is preferably a semi-solid or solid at room temperature and a short curing time. The mixing ratio of resole type phenol formaldehyde resin in thermosetting resin is 70-95
It is preferable to select the weight%. If the compounding ratio is less than 70% by weight, it takes a long time to cure and the productivity is poor, and the finished coating film cannot be formed firmly, but if it exceeds 70% by weight, the cured film is formed firmly. it can.

Acrylic resin copolymerized cation-expanded quaternary ammonium salts that are solid at room temperature have semi-insulating properties, and a synergistic relationship with an epoxy compound that expands the range of electrical conductivity is recognized. Further, it is quick-drying and has an effect of preventing resin dripping at the time of coating.
In addition, the strength of the coating film at the time of completion is increased, and thus the durability against rotation is improved.

The tertiary amine having two 2-hydroxyethyl groups in a molecule which is liquid at normal temperature is preferably a tertiary amine having an acyl group other than the two 2-hydroxyethyl groups in the molecule, and is a solid at room temperature. And the acrylic resin copolymerized cationic type quaternary ammonium salt has a synergistic relationship for expanding the semi-insulating region.

(C) Mixing ratio R [= (c) of a cationic quaternary ammonium salt copolymerized with an acrylic resin at room temperature and a tertiary amine having two 2-hydroxyethyl groups in a molecule liquid at room temperature. ) / (D)] is preferably in the range of 0.3 ≦ R ≦ 0.6.

When the mixing ratio R is 0.3 or less, the coating film becomes hard and brittle and lacks durability, but when the mixing ratio R is 0.3 or more, there is no resin dripping during coating and drying, and the coating film has excellent durability against rolling, A synergistic effect of expanding the range of conductivity with the cationic semi-insulating resin is observed. Further, the mixing ratio R
When the ratio is 0.6 or more, resin dripping occurs during coating and drying, and the curing reaction between the epoxy compound and the resole-type phenol formaldehyde resin is inhibited.

The semi-insulating resin composition for a transfer roller of the present invention, 25 to
It is preferable to use it by dissolving it in 400 parts by weight of an organic solvent, such as methanol, ethanol, or the like.
Alcohols such as isopropanol and butanol; ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as toluene and xylene; and ethers such as methyl cellosolve and ethyl cellosolve. or,
If a water-soluble resol-type phenol formaldehyde resin is used, it can be used as an aqueous resin, but for dip coating, a single solvent or a mixture of two solvents is preferable.

The transfer roller is coated with a resin composition dissolved in an organic solvent on a transfer roll support to a predetermined thickness using a dip coater.After air drying, the temperature is gradually increased from a low temperature in a hot air dryer at 40 ° C to 170 ° C, and the resin is cured. It is formed by forming a conductive resin film.

[Examples and Comparative Examples] Resol type phenol formaldehyde resin is abbreviated as PR, and glycerol polyglycidyl ether is referred to as Epx.
(1), bisphenol A diglycidyl ether is abbreviated as Epx (2), 1,6-hexanediol diglycidyl ether is abbreviated as Epx (3), and Chemistat 250
0 (Sanyo Kasei Kogyo Co., Ltd. is abbreviated as IS, and acrylic resin copolymerized cationic quaternary ammonium salt is abbreviated as IC. Example 1: PR: 90 parts by weight Epx (1): 10 parts by weight On the other hand, IS: 50 parts by weight IC: 75 parts by weight Example 2: PR: 80 parts by weight Epx (1): 20 parts by weight, IS: 50 parts by weight IC: 70 parts by weight Example 3: PR: 70 parts by weight Part: Epx (1): 30 parts by weight, IS: 50 parts by weight IC: 75 parts by weight Example 4: PR: 80 parts by weight Epx (1): 20 parts by weight, IS: 60 parts by weight IC: 90 Parts by weight Example 5: PR: 80 parts by weight Epx (1): 20 parts by weight, IS: 70 parts by weight IC: 105 parts by weight Comparative Example 1: PR: 100 parts by weight, IS: 50 parts by weight IC … 75 parts by weight Comparative Example 2: PR… 100 parts by weight, IS… 70 parts by weight IC… 105 parts by weight Comparative Example 3: PR… 100 parts by weight, IS… 100 parts by weight Comparative Example 4: PR… 100 IC: 100 parts by weight based on parts by weight Comparative Example 5: PR: 8 0 parts by weight Epx (2) ... 20 parts by weight, IS ... 50 parts by weight IC ... 75 parts by weight Comparative Example 6: PR ... 80 parts by weight Epx (3) ... 20 parts by weight, IS ... 50 parts by weight IC ... A composition of 75 parts by weight was prepared. In each case, the solid content and viscosity were adjusted with methyl cellosolve to a suitable solid content and viscosity. The curing conditions were air-drying for 1 hour → 40 ° C x 30 minutes → 90 ° C x 30. Min → 150 ℃ × 30min → 170 ℃
Heating was performed for 1 hour, and the cured product was tested for volume resistivity, hardness, adhesion, and resin dripping during curing. As shown in Table 1, Examples 1, 2, 3, 4, and 5 showed good results in all of volume resistivity, hardness, adhesion, and resin sag.

The conditions and criteria for the test items are as follows.

Resin sag property: applied to a 50 mm wide aluminum plate so as to have a dry film thickness of 100 μm, and after one hour in air-drying, dried in a dryer with the aluminum plate upright, and the resin sag distance was measured.

Volume resistivity; applied voltage 100V, applied time 1 minute, 25 ° C, 60
Measured under% RH conditions.

Adhesion; vertical eleven to 1mm intervals, divided into compartments of 1mm ² units an incision in the transverse eleven cutter knife, at the time of peeling stuck cellophane tape, 1mm ² unit blocks of and how many contact Counting Displayed by the number / 100 pieces.

 Coating film hardness; depends on pencil hardness.

(C) Effects of the Invention As can be seen from the above Examples and Comparative Examples, when the semi-insulating resin composition for a transfer roller of the present invention is used for a transfer roller, the toner can be electrostatically adsorbed and the toner is electrostatically adsorbed. The volume can be set to an adjustable volume resistance, there is no resin dripping at the time of curing, the coating drying property is good, a uniform coating film is obtained, and the appropriate hardness as the transfer roller and excellent durability Have

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical indication (C09D 163/00 133: 02)

Claims (2)

(57) [Claims] (1) A general formula: (Where l, m and n in the formula are integers of 0 to 2) A thermosetting resin comprising 5 to 30 parts by weight of an epoxy compound represented by the following formula and (b) 70 to 95 parts by weight of a resole-type phenol formaldehyde resin. (C) Acrylic resin copolymerized cationic quaternary ammonium salt which is solid at room temperature and (d) a tertiary amine having two 2-hydroxyethyl groups in a molecule which is liquid at room temperature with respect to 100 parts by weight. A semi-insulating resin composition for a transfer roller containing 100 to 175 parts by weight by mixing. 2. A mixing ratio of (c) a cationic quaternary ammonium salt copolymerized with an acrylic resin which is solid at ordinary temperature and (d) a tertiary amine which is liquid at ordinary temperature and has two 2-hydroxyethyl groups in a molecule. 2. The semi-insulating resin composition for a transfer roller according to claim 1, wherein R [= (c) / (d)] is in the range of 0.3 to 0.6.