JP2016011402A - Composition for conductive member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for a conductive member in which the generation of precipitation caused by reaction a catalyst and an ion conductant agent is suppressed.SOLUTION: Provided is a composition for a conductive member used for a conductive member containing at least one elastic layer including polyurethane obtained by reacting polyol, isocyanate and a catalyst, and an ion conductant agent. The catalyst includes an organic tin compound having functional group-containing parts directly coupled to tin atoms, and the molecular weight of at least one functional group-containing part in the functional group-containing parts being below 150.

Description

  The present invention relates to a composition for a conductive member, and in particular, for a conductive member used for a conductive member having at least one elastic layer containing a polyurethane obtained by reacting a polyol, an isocyanate and a catalyst, and an ionic conductive agent. Relates to the composition.

Conventionally, in the production of a conductive roller as a conductive member having an elastic layer containing polyurethane, it is known to use an organic tin compound as a catalyst for urethane reaction (urethane reaction catalyst) (for example, patent document) 1).
Here, in the step of forming the elastic layer containing polyurethane, usually, a mixture (pre-formulation) of an organic tin compound, a polyol and an ionic conductive agent is prepared, and an isocyanate is added to the prepared pre-formulation, thereby ionic conduction. An agent-containing polyurethane is obtained.

JP-A-2005-321764

For example, when dibutyltin dilaurate, an organic tin compound, is used as a catalyst, an unintended reaction occurs between dibutyltin dilaurate and an ionic conductive agent in a pre-formulation (a mixture of dibutyltin dilaurate, polyol, and ionic conductive agent). In addition, since precipitates are generated, it has been found that there is a problem that the pot life (storage period) of the pre-blend is short, and that it is difficult to handle when mass-producing conductive members.
Therefore, in the selection of the organic tin compound used for the production of a conductive member having an elastic layer containing polyurethane, a catalyst in which the generation of precipitates in the pre-formulation is suppressed is desired.

  An object of this invention is to provide the composition for electroconductive members by which generation | occurrence | production of precipitation produced by reaction of a catalyst and an ionic conductive agent was suppressed.

The composition for a conductive member of the present invention is a composition for a conductive member used for a conductive member having at least one elastic layer containing a polyurethane obtained by reacting a polyol, an isocyanate and a catalyst, and an ionic conductive agent. The catalyst contains an organic tin compound having a functional group-containing portion that directly binds to a tin atom, and the molecular weight of at least one functional group-containing portion of the functional group-containing portion is less than 150. And
According to this structure, generation | occurrence | production of the precipitation which arises by reaction of a catalyst and an ionic conductive agent can be suppressed.

In the present specification, the “functional group-containing portion that is directly bonded to a tin atom” refers to a structural portion that includes a specific functional group and does not include a tin atom in a tin compound having a specific functional group. For example, if the specific functional group is an ester group, it refers to a structural part containing an ester group (for example, a structural part of “OCOCH ₃ ” in a compound represented by the following chemical formula (1)). The compound represented by the chemical formula (1) has two “functional group-containing parts (OCOCH ₃ )” having the same structure.
In the compound represented by the following chemical formula (2), the “functional group-containing portion directly bonded to a tin atom” refers to a structural portion of “OCOCH = CHCOOCH ₂ CH ₃ ”. The compound represented by the chemical formula (2) has two “functional group-containing parts (OCOCH = CHCOOCH ₂ CH ₃ )” having the same structure.
In the present specification, the “organotin compound” is a tin compound having, for example, a hydrocarbon.

  In the conductive member composition of the present invention, the functional group-containing part is preferably an ester group-containing part. According to this structure, generation | occurrence | production of the precipitation which arises by reaction with a catalyst and an ionic conductive agent can be suppressed more.

  In the composition for a conductive member of the present invention, the organotin compound has one tin atom, two ester group-containing parts, and the molecular weights of the two ester group-containing parts are both 150. It is preferable that it is less than. According to this structure, generation | occurrence | production of the precipitation which arises by reaction of a catalyst and an ionic conductive agent can further be suppressed.

In the composition for a conductive member of the present invention, the organotin compound is preferably a compound represented by the following general formula (I). According to this structure, generation | occurrence | production of the precipitation which arises by reaction with a catalyst and an ionic conductive agent can be suppressed further.
[In the general formula (I),
R ¹ represents a linear hydrocarbon having 4 to 8 carbon atoms,
R ² is hydrogen or a structure having 1 to 6 carbon atoms, and may have an ester bond or an unsaturated bond. ]

  In the composition for a conductive member of the present invention, the organotin compound is preferably at least one of dioctyltin diacetate and dioctyltin bis (ethylmalate). According to this configuration, the occurrence of precipitation caused by the reaction between the catalyst and the ionic conductive agent can be particularly suppressed.

  In the conductive member composition of the present invention, the blending amount of the catalyst with respect to the polyol is preferably 0.01 to 2.0% by mass. According to this structure, reaction of a polyol and isocyanate can be adjusted moderately.

  In the composition for a conductive member of the present invention, the ionic conductive agent is preferably an alkali metal salt. If the ionic conductive agent is an alkali metal salt, precipitation is likely to occur. According to this configuration, even if the ionic conductive agent is an alkali metal salt, the occurrence of precipitation can be suppressed.

  The composition for a conductive member of the present invention is preferably used for a charging member. If the composition for conductive members of the present invention is applied, the charging member can be produced while suppressing precipitation.

  ADVANTAGE OF THE INVENTION According to this invention, the composition for electroconductive members in which generation | occurrence | production of precipitation produced by reaction of a catalyst and an ionic conductive agent was suppressed can be provided.

FIG. 1 is a cross-sectional view of an example of a conductive member produced using the composition for a conductive member of the present invention. FIG. 2 is a photograph of the appearance of the pre-blend of Comparative Example 1.

  The form for implementing this invention is illustrated below.

(Composition for conductive member)
The composition for a conductive member of the present invention is used for a conductive member, and includes at least polyurethane and an ionic conductive agent, and further includes other components as necessary.

<Conductive member>
The conductive member includes at least one elastic layer, and further includes a shaft, a surface layer, and other members as necessary.

  FIG. 1 is a cross-sectional view of an example of a conductive member. A conductive member 1 shown in FIG. 1 includes a shaft 2 that is attached by being axially supported at both ends in the length direction, and an elastic layer 3 disposed on the outer side in the radial direction of the shaft 2. The conductive member 1 shown in FIG. 1 has only one elastic layer 3, but may have two or more elastic layers. The conductive member 1 shown in FIG. 1 includes a surface layer 4 on the outer side in the radial direction of the elastic layer 3. In the conductive member 1 shown in FIG. 1, the surface layer 4 includes fine particles 5, but it is not essential to contain fine particles. Furthermore, although the conductive member 1 shown in FIG. 1 has only one surface layer 4, it may have two or more surface layers.

There is no restriction | limiting in particular as a kind of said electroconductive member, According to the objective, it can select suitably, For example, a charging member, a toner supply member, a developing member, a transfer member, a cleaning member, a fixing member etc. are mentioned. .
Among these, if the composition for a conductive member of the present invention is applied to a charging member, it is advantageous in terms of manufacturing convenience in that the pot life in the manufacturing process can be prolonged while maintaining the quality of the charging member. It is.

<< Elastic layer >>
The elastic layer in the conductive member includes at least polyurethane and an ionic conductive agent, and further includes other components as necessary.

-Polyurethane-
The polyurethane is obtained by reacting at least a polyol, an isocyanate and a catalyst. The polyurethane may be either unmodified polyurethane or modified polyurethane.

--Polyol--
The polyol is not particularly limited as long as it is a compound having a plurality of hydroxyl groups (OH groups), and can be appropriately selected according to the purpose. For example, polyether polyol, polyester polyol, polytetramethylene glycol, polybutadiene polyol, Examples include alkylene oxide-modified polybutadiene polyol and polyisoprene polyol. These may be used individually by 1 type and may use 2 or more types together.

--Isocyanate--
The isocyanate is not particularly limited as long as it has an isocyanate group, and can be appropriately selected according to the purpose. For example, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), Isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, hexamethylene diisocyanate (HDI); these isocyanurate-modified products, carbodiimide-modified products, glycol-modified products, and the like. These may be used individually by 1 type and may use 2 or more types together.

--Catalyst--
The catalyst includes an organotin compound having a functional group-containing portion that directly bonds to a tin atom.
Here, the organotin compound may have one or more tin atoms. Moreover, the said organotin compound may have one or more functional group containing parts in one tin atom. Among these, an organic tin compound having one tin atom and having two functional group-containing portions in the tin atom is preferable in that precipitation is hardly generated.
The molecular weight of the functional group-containing part is not particularly limited as long as it is less than 150 and can be appropriately selected according to the purpose, but is preferably 50 or more and less than 150.
When the molecular weight of the functional group-containing portion is 150 or more, precipitation easily occurs due to reaction with the ionic conductive agent. On the other hand, when the molecular weight of the functional group-containing portion is within the preferred range, it is advantageous in that the occurrence of precipitation caused by the reaction between the catalyst and the ionic conductive agent can be further suppressed.
In addition, when the said organic tin compound has two or more functional group containing parts couple | bonded with a tin atom, at least one functional group containing part should just be less than 150 among these functional group containing parts.

--- Functional group containing part ---
There is no restriction | limiting in particular as said functional group containing part, According to the objective, it can select suitably, For example, an ester group containing part, an ether group containing part, an amide group containing part, an imide group containing part, etc. are mentioned. . These may be used alone or in combination of two or more.
Among these, an ester group-containing part is preferable in that precipitation is less likely to occur.

--- Structure of organotin compound ---
As a structure of the said organic tin compound, the structure represented by the following general formula (I) is mentioned suitably, for example.
[In the general formula (I),
R ¹ represents a linear hydrocarbon having 4 to 8 carbon atoms,
R ² is hydrogen or a structure having 1 to 6 carbon atoms, and may have an ester bond or an unsaturated bond. ]

----- R ¹ -----
The carbon number of the linear hydrocarbon of R ^1, is not particularly limited and may be appropriately selected depending on the intended purpose, 4-8 is preferred.

----- R ² -----
R ² is not particularly limited as long as it is hydrogen or a structure having 1 to 6 carbon atoms. For example, R ² may have a bond such as an ester bond, an ether bond, or an amide bond, or is unsaturated in the structure. You may have a bond.

--- Specific examples of organotin compounds ---
As a specific example of the organic tin compound, an organic tin compound having a functional group-containing portion directly bonded to a tin atom and having a molecular weight of at least one functional group-containing portion of the functional group-containing portion of less than 150 is particularly preferable. There is no restriction | limiting, According to the objective, it can select suitably, For example, the compound dioctyl tin diacetate (For example, a manufacturing company name: Nitto Kasei Co., Ltd., brand name: U820) represented by following Chemical formula (1), the following Examples include dioctyltin bis (ethyl maleate) represented by chemical formula (2) (for example, manufacturing company name: Nitto Kasei Co., Ltd., trade name: U840), dioctyltin malate, dioctyltin diacetate, and the like. These may be used alone or in combination of two. These organotin compounds are also environmentally friendly catalysts and are good as catalysts used in production.
Among these, the dioctyltin diacetate is preferable because it can particularly suppress the occurrence of precipitation caused by the reaction between the catalyst and the ionic conductive agent. Moreover, it is preferable at the point which can have a sufficient effect in a small quantity rather than another catalyst.

--- Blending amount of catalyst with respect to polyol ---
There is no restriction | limiting in particular as the compounding quantity with respect to the polyol of the said catalyst, Although it can select suitably according to the objective, 0.01-2.0 mass% is preferable, and 0.2-1.3 mass% is more. preferable.
When the blending amount of the catalyst with respect to the polyol is less than 0.01% by mass, the polyol and the isocyanate may not react, and when it exceeds 2.0% by mass, the polyol and the isocyanate react excessively to increase productivity. May get worse. On the other hand, when the blending amount of the catalyst with respect to the polyol is within the preferable range or the more preferable range, it is advantageous in that the reaction between the polyol and the isocyanate can be appropriately adjusted. Moreover, it is advantageous in that both productivity and quality of the conductive member can be achieved.

-Ionic conductive agent-
The ionic conductive agent is not particularly limited and may be appropriately selected depending on the purpose. For example, alkali metal salts, alkaline earth metal salts, quaternary ammonium perchlorates, chlorates, hydrochlorides, Examples thereof include bromate, iodate, borofluoride, sulfate, trifluoromethyl sulfate, sulfonate, bis (trifluoromethanesulfonic acid) imide salt, and the like. These may be used individually by 1 type and may use 2 or more types together.

--Alkali metal salt--
There is no restriction | limiting in particular as alkali metal salt, According to the objective, it can select suitably, For example, lithium salt, sodium salt, potassium salt etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.
Among these, lithium salts are preferable from the viewpoint of increasing the conductivity (lowering the resistance value).

--- Lithium salt ---
There is no restriction | limiting in particular as lithium salt, According to the objective, it can select suitably, For example, lithium salt of organic acids, such as boric acid, a sulfonic acid, trifluoromethanesulfonic acid; Perchloric acid, tetrafluoroboric acid Inorganic acid lithium salts; organoboron complex lithium salts; and the like. These may be used individually by 1 type and may use 2 or more types together.
Specific examples of the lithium salt include Li [B (C ₁₄ H ₁₀ O ₃ ) ₂ ], Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, for example. , LiClO ₄ , LiBF ₄ , LiPF ₆ , LiCF ₃ SO ₃ , LiAsF ₆ , LiC ₄ F ₉ SO ₃ , and the like.
Among these, the organic boron complex lithium salt is advantageous in that it hardly generates rust on the shaft of the conductive member, and Li [B (C ₁₄ H ₁₀ O ₃ ) ₂ ] rusts on the shaft of the conductive member. It is more advantageous in that it is difficult to reliably generate.

-Other ingredients-
There is no restriction | limiting in particular as said other component, According to the objective, it can select suitably, For example, a foam stabilizer, a filler, a peptizer, a foaming agent, a plasticizer, a softening agent, a tackifier, adhesion Examples thereof include an inhibitor, a separating agent, a release agent, an extender, a colorant, a crosslinking agent, a vulcanizing agent, a polymerization initiator, and a polymerization inhibitor. These may be used individually by 1 type and may use 2 or more types together.

<< Shaft >>
The conductive member has a shaft as necessary.
The shaft is not particularly limited as long as it has good conductivity, and can be appropriately selected according to the purpose. Examples thereof include hollow cylinders, solid cylinders, and the like made of metal or resin. It is done. These may be used individually by 1 type and may use 2 or more types together.

<< surface layer >>
The conductive member has a surface layer as necessary.
The surface layer is used to increase the hardness of the member, to control the chargeability and adhesion to the toner, to reduce the frictional force with the photosensitive drum and stratified blade, etc., and to prevent contamination of the photosensitive drum etc. by the elastic layer. , Formed on the outer peripheral surface of the elastic layer.
There is no restriction | limiting in particular as the material contained in the said surface layer, According to the objective, it can select suitably, For example, an ultraviolet curable resin, a fluorine-containing resin, microparticles | fine-particles, a silicon-containing resin etc. are mentioned. These may be used individually by 1 type and may use 2 or more types together.

<< Other parts >>
The conductive member has other members as necessary.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not limited to the following Example at all, In the range which does not change the summary, it can change suitably.

(Example 1)
<Preparation of preparation>
100 parts by weight of polyol (manufacturer: Asahi Glass Co., Ltd., trade name: Exenol 420), 16 parts by weight of foam stabilizer (manufacturer: Toray Dow Corning, trade name: SF2937F), ionic conductive agent (manufacturer: Japan) Carlit Co., Ltd., trade name: PEL-46 (organic boron complex lithium salt) 1 part by mass, and dioctyltin diacetate (manufacturer name: Nitto Kasei Co., Ltd., trade name: U820, tin content 25.7%). 2 parts by mass were mixed and stirred to obtain a pre-formulation (mixture of polyol, foam stabilizer, ionic conductive agent and catalyst).

<Production of conductive member (roller)>
100 parts by weight of a pre-blend, 462 parts by weight of isocyanate (manufacturer name: Asahi Glass Co., Ltd., trade name: polyol-modified TDI), and 9 parts by weight of fine particles (manufacturer name: Denki Kagaku Kogyo, trade name: Denka Black) On the 14th day after preparing the pre-formulation, foamed by mechanical floss method, and injected into a cylindrical mold set with a shaft, and has an elastic layer made of polyurethane foam by RIM molding A conductive member was produced.

For the pre-blend, elastic layer substrate, and conductive member obtained as described above, (i) Appearance evaluation of pre-blend, (ii) Resistance evaluation of elastic layer substrate and conductive member, (iii) The hardness evaluation of the elastic layer and the conductive member, (iv) the appearance evaluation of the elastic layer and the conductive member, and (v) the image test using the conductive member were evaluated by the following methods. The evaluation results are shown in Tables 1 and 2 below.

<Appearance evaluation of pre-blend>
The pre-blend was left to stand at room temperature for 14 days, and the appearance of the pre-blend was confirmed after 1 day, 7 days, and 14 days from the day the pre-blend was prepared. In the case of the pre-formulation, when the catalyst and the ionic conductive agent reacted, a white precipitate was formed, and the formation of the precipitate could be confirmed with the naked eye. The results are shown in Table 1. Evaluation criteria were evaluated by ○, Δ, and ×. If it is ○, there is no practical problem.

<Resistance evaluation>
Table 2 shows the results of applying an applied voltage of 10 V to the obtained elastic layer base material, applying an applied voltage of 200 V to the obtained conductive member, and measuring the current value.

<Hardness evaluation>
Table 2 shows the results of measuring the Asker hardness of the obtained elastic layer substrate and conductive member using a micro hardness meter (MD-1 manufactured by Kobunshi Keiki Co., Ltd.).

<Appearance evaluation>
The external appearance of the obtained elastic layer base material and conductive member was visually evaluated. The results are shown in Table 2. The evaluation criteria were evaluated by ◯ ×. ○ indicates that a substrate that does not recognize defects such as dents (voids) on the surface of the substrate can be produced, and × indicates that it is difficult to produce the substrate itself, or even if the substrate can be produced, it is recessed on the surface of the substrate. It means to recognize defects such as (void). If it is ○, there is no practical problem.

<Image evaluation>
A conductive member was incorporated in the cartridge, mounted on a printer, and imaged to evaluate the presence or absence of image defects. The results are shown in Table 2. Evaluation criteria were evaluated by ○ and ×. ○ indicates that it is possible to produce a roller that does not easily cause image defects such as fog, and × indicates that it is difficult to produce the roller itself, or that even if the roller can be produced, image defects such as fog occur on the roller. means. If it is ○, there is no practical problem.

(Example 2)
In Example 1, instead of using dioctyltin diacetate, 0.64 parts by mass of dioctyltin bis (ethylmalate) (manufacturer name: Nitto Kasei Co., Ltd., trade name: U840, tin content 18.8%) is used. Except for the above, a pre-blend, an elastic layer base material and a conductive member were produced in the same manner as in Example 1, and the same evaluation was performed. The evaluation results are shown in Tables 1 and 2 below.

(Comparative Example 1)
In Example 1, instead of using dioctyltin diacetate, dibutyltin dilaurate (manufacturer name: Nitto Kasei Co., Ltd., trade name: U100) 0.32 parts by mass, and isocyanate and fine particles were pre-blended. A pre-blend, an elastic layer base material and a conductive member were prepared in the same manner as in Example 1 except that the mixture was mixed on the seventh day from the date of preparation of the pre-blend, and the same evaluation was performed. Went. The evaluation results are shown in Tables 1 and 2 below. Furthermore, the photograph of the external appearance on the 14th day after pre-formulation preparation is shown in FIG.

(Comparative Example 2)
In Example 1, instead of using dioctyltin diacetate, dibutyltin bis (oil malate) (manufacturer name: Nitto Kasei Co., Ltd., trade name: U15) was used except that 0.32 parts by mass were used. In the same manner as in Example 1, a pre-blend, an elastic layer base material and a conductive member were prepared and evaluated in the same manner. The evaluation results are shown in Tables 1 and 2 below.

  As shown in Table 1, the pre-formulations of Examples 1 and 2 did not precipitate at least after 14 days. On the other hand, in the pre-blend of Comparative Example 1, a precipitate was generated after 14 days. The pre-blend of Comparative Example 2 already had a precipitate after 1 day. Since the catalyst used in Examples 1 and 2 does not cause an unexpected reaction (precipitation reaction) in the pre-formulation, the pot life (storage period) of the pre-formation is extended, and the productivity of the conductive member is increased. Will improve.

  The details of the mechanism by which the catalysts of Comparative Examples 1 and 2 having a functional group-containing molecular weight of 150 or more react with the ionic conductive agent are not clear, but the cause is that the catalyst decomposes when the ionic conductive agent coexists. it is conceivable that. Since the molecular weight of the functional group-containing part of the catalyst affects the strength of the Sn—O covalent bond of the catalyst, the catalysts of Examples 1 and 2 in which the molecular weight of the functional group-containing part is less than 150 are stable in the covalent bond. It is considered that the catalyst is not easily affected by the ionic conductive agent.

  As shown in Table 2, it can be seen that the elastic layer base materials and conductive members of Examples 1 and 2 exhibit the same characteristics (current value, Asker hardness, appearance, image evaluation) as Comparative Example 1.

  The conductive member composition of the present invention includes, for example, a conductive member (conductive roller), a charging member (charging roller), a toner supply member (toner supply roller), a developing member (developing roller), and a transfer member (transfer roller). ), A cleaning member (cleaning roller), a fixing member (fixing roller), and the like.

DESCRIPTION OF SYMBOLS 1 Conductive member 2 Shaft 3 Elastic layer 4 Surface layer 5 Fine particle

Claims (8)

A composition for a conductive member used for a conductive member having at least one elastic layer containing a polyurethane obtained by reacting a polyol, an isocyanate and a catalyst, and an ionic conductive agent,
The catalyst includes an organic tin compound having a functional group-containing portion that directly bonds to a tin atom,
The composition for conductive members, wherein the molecular weight of at least one of the functional group-containing parts is less than 150.   The composition for conductive members according to claim 1, wherein the functional group-containing part is an ester group-containing part.   The electroconductive compound according to claim 2, wherein the organic tin compound has one tin atom, two ester group-containing parts, and the molecular weights of the two ester group-containing parts are both less than 150. Composition for adhesive members. The composition for conductive members according to any one of claims 1 to 3, wherein the organotin compound is represented by the following general formula (I).
[In the general formula (I),
R ¹ represents a linear hydrocarbon having 4 to 8 carbon atoms,
R ² is hydrogen or a structure having 1 to 6 carbon atoms, and may have an ester bond or an unsaturated bond. ]   The composition for conductive members according to any one of claims 1 to 4, wherein the organic tin compound is at least one of dioctyltin diacetate and dioctyltin bis (ethylmalate).   The composition for conductive members according to any one of claims 1 to 5, wherein a blending amount of the catalyst with respect to the polyol is 0.01 to 2.0 mass%.   The composition for conductive members according to any one of claims 1 to 6, wherein the ionic conductive agent is an alkali metal salt.   The composition for conductive members according to claim 1, wherein the composition for conductive members is used for a charging member.