JP3293495B2 - Electrophotographic carrier coating agent and electrophotographic carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a coating agent for an electrophotographic carrier and an electrophotographic carrier coated with the coating agent.

[0002]

2. Description of the Related Art The developer of a two-component dry copying machine is composed of two components, a fine toner and a larger carrier. The toner and the carrier are electrostatically charged to different signs. A visible image is formed by electrostatically adhering the charged toner to the electrostatic latent image formed on the photoreceptor, and copying is achieved by transferring and fixing this image to a transfer sheet. You.
In this case, oxidized or unoxidized iron powder is usually used as a carrier. However, if this powder is used as it is in the form of a mixture with toner, the triboelectrification characteristics for the toner are insufficient and the toner is not used. In addition, since the toner adheres to the carrier surface to form a toner film (spent), the charging characteristics of the carrier change with time, resulting in a short life of the developer.

Further, there is a disadvantage that the difference in charge characteristics of the carrier between dry and wet conditions is large.

In order to prevent such defects, an acrylic resin, a styrene-acrylic copolymer,
2. Description of the Related Art Coating with a resin such as a silicone resin, a polyester, or a fluororesin is performed.

[0005] Among them, silicone resin, fluororesin and the like are attracting attention because they can reduce the phenomenon of spent due to their low surface energy. In particular, in the case of silicone resin, it can be dissolved in various kinds of solvents and various molecular structures can be formed by selecting a monomer. Therefore, carriers having various charge levels depending on the selection, the third component, and the processing conditions can be used. There is an advantage that can be made. For example, a method of curing a room-temperature moisture-curable silicone resin at a high temperature (Japanese Patent Publication No. 62-61948) or a silicone resin containing a tin compound (Japanese Patent Publication No. 2-3181)
And JP-A-6-1392) have proposed a method of controlling the charge amount. However, these methods have a problem that the charge amount increases with the number of copies. In particular, in the case of heating and curing using a room-temperature moisture-curable silicone resin, the reaction does not proceed during heating because there is no water essential for the reaction, and the reaction proceeds during cooling. Therefore, there is a problem that the charge amount easily varies depending on the season due to the influence of the atmosphere during cooling. In addition, deoxime-curable silicone resins generally used as room-temperature-curable resins are concerned about the toxicity of decomposed products of oximes that are by-produced.

[0006] On the other hand, the heat-curable silicone resin usually cures due to the condensation of silanol, but has a problem that the amount of silanol, which is a curing point, is small, the drying property at low temperatures is poor, blocking occurs, and coating is difficult. there were. In particular, a methyl-based silicone resin having a high charge level has a problem that the wettability is poor and a uniform coating cannot be obtained.

Further, the above-mentioned silicone resin has a higher charge level than other organic resins, but is lower than fluororesins. In the case of a toner which does not contain a large amount of a charge control agent and is hardly charged, a fluorosilicone resin ( JP-A-2-1
6573, 2-103563, Tokuhei 2-318
No. 1, JP-A-4-343363 and JP-A-7-72668) have been used. However, the introduction of fluorine deteriorates the curability, deteriorates the drying property at low temperatures, causes blocking, and has a problem that coating is difficult.

[0008] The present invention has been made in view of the above circumstances,
A coating agent for an electrophotographic carrier containing a silanol condensation-curable organopolysiloxane as a main component, which is excellent in drying property, has a high charge level, and can provide stable charging characteristics without spent. The purpose of the present invention is to provide a carrier for electrophotography.

[0009]

Means for Solving the Problems and Embodiments of the Invention
The inventors have conducted intensive studies to achieve the above object.
As a result, the following average composition formula (1) R¹ _aSi (OH)_b(X¹)_cO_{(4-abc) / 2} (1) (where R¹Is also a hydrogen atom or an unsubstituted group having 1 to 18 carbon atoms
Or two or more selected from substituted monovalent hydrocarbon groups
The above group, X¹Represents a hydrolyzable group, and a, b, and c represent
0.6 ≦ a ≦ 1.8, 0.2 ≦ b ≦ 0.8, 0 ≦ c ≦
0.5, 0.8 ≦ a + b + c ≦ 2.0
You. ) And the following general formula (2):¹ Si (OH)_d(X¹)_eO_{(3-de) / 2} (2) (where R¹And X¹Has the same meaning as above, and d and e
Are 0, 1 or 2 respectively, and d + e = 0, 1 or
Is an integer satisfying 2. ) Is 3
0-100 mol%, and the structure of the formula (2)
The unit is the following general formulas (3a) and (3b):¹Si (OH) O_2/2 (3a) R¹Six¹O_2/2 (3b) (wherein, R¹And X¹Has the same meaning as described above. )
Containing a total of 30 to 80 mol% of the structural unit
Organopolysiloxane having an average molecular weight of 500 or more
The main component of the coating agent for electrophotographic carriers
In this case, this organopolysiloxane is
It is a curing type and is not affected by the atmosphere during cooling.
Stable charge amount and high content of silanol groups
This makes it possible to cure at low temperatures, dry well, and
Hard and flexible, this organopolysilo
Coating carrier core particles with a cured product of xan
The carrier for electrophotography obtained by
Polysiloxane has excellent drying properties, so blocking
And the charge amount is high.
Change over time), without spent, stable charging
Durability and adhesion due to its characteristics and excellent flexibility
Found that the properties are also good, and led to the present invention.
It is.

Accordingly, the present invention provides a coating agent for an electrophotographic carrier containing the above-mentioned organopolysiloxane as a main component, and an electrophotographic carrier obtained by coating a carrier core surface with a cured product of the coating agent.

Hereinafter, the present invention will be described in more detail.
The coating agent for an electrophotographic carrier of the present invention comprises an organopolysiloxane represented by the following average composition formula (1): R ¹ _a Si (OH) _b (X ¹ ) _c O _{(4-abc) / 2} (1) Main component.

Here, R ¹ is a hydrogen atom or a compound having 1 to 1 carbon atoms.
One or more groups selected from 18 unsubstituted or substituted monovalent hydrocarbon groups. Unsubstituted monovalent hydrocarbon groups include methyl, ethyl, propyl, butyl,
Hexyl group, decyl group, alkyl group such as octadecyl group, vinyl group, allyl group, alkenyl group such as propenyl group, butenyl group, phenyl group, tolyl group, aryl group such as naphthyl group, benzyl group, phenylethyl group etc. Aralkyl groups and the like. Examples of the substituted monovalent hydrocarbon group include those obtained by substituting some or all of the hydrogen atoms of these unsubstituted monovalent hydrocarbon groups with a substituent. In this case, specific substituents include (i) a halogen atom such as fluorine and chlorine, (ii) an alkenyl group such as a vinyl group, (iii) an epoxy functional group such as a glycidyloxy group and an epoxycyclohexyl group, and (iv) Methacrylic group,
(Meth) acrylic functional groups such as acrylic groups, (v) amino functional groups such as amino groups, aminoethyl groups, phenylamino groups, dibutylamino groups, (vi) sulfur-containing functional groups such as mercapto groups and tetrasulfide groups, (Vii) an alkyl ether group such as a (polyoxyalkylene) alkyl ether group, (viii) an anionic group such as a carboxyl group and a sulfonyl group, and (ix) a group containing a quaternary ammonium salt structure. Examples of such a substituted monovalent hydrocarbon group include a trifluoropropyl group, a perfluorobutylethyl group, a perfluorooctylethyl group, a γ-chloropropyl group, a β-chloromethylphenylethyl group, and a γ-glycidyloxy group. Propyl group, β-
(3,4-epoxycyclohexyl) ethyl group, 5,6
An epoxyhexyl group, a 9,10-epoxydecyl group,
γ-aminopropyl group, N- (2-aminoethyl) aminopropyl group, N-phenylaminopropyl group, dibutylaminopropyl group, γ-methacryloxypropyl group,
γ-acryloxypropyl group, γ-mercaptopropyl group, β- (4-mercaptomethylphenyl) ethyl group,
Examples thereof include a polyoxyethyleneoxypropyl group, a γ-hydroxycarbonylpropyl group, and a γ-tributylammoniumpropyl group. R ¹ is preferably an alkyl group, a phenyl group, or a 3,3,3-trifluoropropyl group, particularly preferably an alkyl group and a phenyl group from the viewpoint of charging characteristics, and particularly preferably a methyl group and a phenyl group.

X ¹ is a hydrolyzable group, such as a halogen atom such as chlorine, an alkoxy group having 1 to 6 carbon atoms (a methoxy group,
Ethoxy, butoxy, isopropenoxy, etc.), acyloxy (acetoxy, etc.), amino, oxime and the like.
Ethoxy groups are preferred. X ¹ is a hydrolyzable group which is not hydrolyzed and remains in a small amount during the hydrolysis of the hydrolyzable group-containing silane described later, and is usually not contained at all or contained in a small amount.

A, b and c are 0.6 ≦ a ≦ 1.8,
More preferably, 0.9 ≦ a ≦ 1.6, 0.2 ≦ b ≦ 0.
8, more preferably 0.25 ≦ b ≦ 0.6, 0 ≦ c ≦
0.5, more preferably 0 ≦ c ≦ 0.3, and 0.8
≦ a + b + c ≦ 2.0, more preferably 1.0 ≦ a + b
+ C ≦ 1.8.

That is, the organopolysiloxane of the present invention essentially comprises a trifunctional siloxane unit (T unit), a monofunctional siloxane unit (M unit), a bifunctional siloxane unit (D unit), and a tetrafunctional siloxane unit (Q unit). ) May be included. In this case, in the present invention, “functional” means having an oxygen atom (—O—Si≡), a hydroxyl group, and a hydrolyzable group bonded to one silicon atom. Is 3
Is the case.

It is preferable that the organopolysiloxane of the formula (1) of the present invention contains T unit as a main component among them, and in order to further increase the hardness of the cured film, it is good to use mainly Q unit in combination. Conversely, for the purpose of imparting flexibility to the cured film, it is preferred to use mainly D units. The range of the number of moles a of the organic group R ^{1 in} 1 mole of Si atom is determined by these structural units, and the range is 0.6 ≦ a ≦ 1.8 as described above. If it is less than 0.6 (the number of Q units is large), cracks are likely to occur and the mechanical strength is weak. On the other hand, if the ratio exceeds 1.8 (the number of D units and M units increases), the crosslink density decreases and the hardness decreases. Further, the number of moles b of silanol in one mole of Si atom is 0.2 ≦ b ≦ 0.8 as described above. If it is less than 0.2, the drying property is deteriorated. If it exceeds 0.8, the cured film is hard but brittle. Si
The number of moles c of the hydrolyzable group X ¹ in one mole of the atom satisfies 0 ≦ c ≦ 0.5 as described above. It is preferable that the number of these functional groups is as small as possible. However, when it exceeds 0.5, the drying property deteriorates and the charge amount becomes low. Furthermore, a + b
If + c is less than 0.8, the storage stability becomes poor, and a +
When b + c exceeds 2.0, the drying property deteriorates.

The organopolysiloxane of the formula (1) of the present invention
Is further represented by the following general formula (2):¹ Si (OH)_d(X¹)_eO_{(3-de) / 2} (2) 30 to 100 mol% of the structural unit represented by
Or 60 to 100 mol%. This unit is 30 mol
% Is preferable because the formed film has low hardness.
I don't. The remaining structural units are represented by R¹ _TwoSiO
_2/20 to 70 mol% of units, especially 0 to 40 mol%, R¹ _ThreeS
iO_1/20-40 mol% of units, especially 0-20 mol%, S
iO_4/2The unit is 0 to 70 mol%, particularly 0 to 40 mol%.
(R¹Has the same meaning as described above).

Here, in the equation (2), R¹, X¹Is above
Where d and e are 0, 1 or 2,
D + e = 0, 1 or 2. Follow
The unit of the formula (2) is R¹Si (OH) O_2/2 (3a) R¹Six¹O_2/2 (3b) R¹SiO_3/2 (4) R¹Si (OH)_TwoSiO_1/2 (5a) R¹Si (OH) X¹SiO_1/2 (5b) R¹Six¹ _TwoO_1/2 The present invention comprises one or more units represented by (5c).
Is represented by the above formula (2)
The structural unit represented by the above formula (3a) or (3b)
30 to 80 mol% in total, more preferably 35 to 7 mol%.
It is necessary to contain 0 mol%, and thereby high curability
While maintaining good storage stability, and also as a cured coating
Flexibility can be imparted. In contrast, equation (3)
If the total of the units a) and (3b) is less than 30 mol%,
Of silanol groups contributing to the curing of luganopolysiloxane
The absolute amount is insufficient, and the hardness of the cured film is insufficient. Further
The charge amount is low, and the drying property during coating is poor,
It is not preferable because it causes blocking and the like.
On the other hand, the total content of the units of the formulas (3a) and (3b) is
In order to make it exceed mol%, it is necessary to
The degree of polymerization must be kept low because the formation of
It is necessary to form a chain or ring structure at low polymerization degree
Is difficult, the cured film has high crystallinity, flexibility, strength
Run out. In addition, storage stability in a solution is reduced.
Not preferred.

Further, the organopolysiloxane of the present invention has a number average molecular weight of 500 or more, preferably 500 to 1
0000, more preferably 700-5000. If the number average molecular weight is less than 500, an appropriate structure cannot be secured, so that good flexibility cannot be obtained and storage stability is poor. Further, it is not preferable because the drying property at the time of coating is inferior and blocking or the like occurs.

Although the method for producing the organopolysiloxane of the present invention is not particularly limited, the following general formula (6): R ¹ _n SiX ² _4-n (6) (wherein, R ¹ has the same meaning as described above) .X ² above X ¹
And the same hydrolyzable group or OH group. n is 0, 1,
2 or 3. ) Is preferably produced by hydrolyzing one or two or more silane monomers or partial hydrolysates or mixed partial hydrolysates thereof. However, in this case, it is necessary to use a trifunctional silane represented by R ¹ SiX ² ₃ at least 30 mol%.

Illustrating these silane monomers, 3
As the functional silane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltributoxysilane, methyltri (methylethylketoxime) silane, methyltriisopropenoxysilane, methyltriacetoxysilane, methyltrichlorosilane, ethyltrisilane Methoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, decyltrimethoxysilane, octadecyltrimethoxysilane,
Vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (methylethylketoxime) silane,
5-hexenyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltrichlorosilane, trifluoropropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane,
γ-glycidoxypropyltriethoxysilane, γ-
(Meth) acryloxypropyltrimethoxysilane, γ
-(Meth) acryloxypropyltriethoxysilane,
γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane and the like.Other functional silanes include γ-glycidoxypropyl Methyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ-aminopropylmethyldimethoxysilane, γ- Aminopropylmethyldiethoxysilane,
γ-mercaptopropylmethyldimethoxysilane, γ-
Mercaptopropylmethyldiethoxysilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, dimethoxydiacetoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylbutoxysilane, dimethyldiisopropenoxysilane, dimethyldichlorosilane, dimethyl Diacetoxysilane,
Hexamethylcyclotrisilazane, ethylmethyldimethoxysilane, propylmethyldimethoxysilane, hexylmethyldimethoxysilane, cyclohexylmethyldimethoxysilane, decylmethyldimethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane,
Examples thereof include phenylmethyldimethoxysilane, phenylethyldiethoxysilane, diphenyldichlorosilane, phenylmethyldichlorosilane, and trimethylmethoxysilane, and also include partially hydrolyzed products thereof. The usable organosilicon compound is not limited to this. Further, a cyclic silane compound having no hydrolyzable group may be allowed to coexist therewith.

Water is added to such a silane or a mixture thereof in the presence of a catalyst to effect hydrolysis. In addition,
A solvent or the like may be present during the hydrolysis.

As the hydrolysis catalyst, conventionally known catalysts can be used. In particular, acidic hydrogen halides, carboxylic acids, sulfonic acids, acidic or basic inorganic salts, ion exchange resins, organometallic catalysts and the like can be used. preferable. Examples include hydrogen fluoride, hydrochloric acid, nitric acid, sulfuric acid, acetic acid, organic acids represented by maleic acid, methylsulfonic acid, and cation exchange resins having sulfonic acid groups or carboxylic acid groups on the surface. The amount of the hydrolysis catalyst is preferably in the range of 0.001 to 10 mol% based on 1 mol of the hydrolyzable group on the silicon atom.

The amount of water is 0.8 to 100 of the amount required for hydrolysis (0.5 mol per mol of hydrolyzable group).
If it is 0 times and less than 0.8 times, the amount of water in the reaction system is small, and the amount of silanol becomes insufficient. If it exceeds 1,000 times, the acid concentration becomes low, the reaction does not proceed easily, and the pot yield becomes extremely low.

Solvents that coexist and are diluted during the hydrolysis include ketones such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and acetylacetone, methanol, ethanol, isopropyl alcohol, n-butanol, isobutanol, and the like. t-
Alcohols such as butanol, t-amyl alcohol, butyl cellosolve, 3-methyl-3-methoxybutanol, diacetone alcohol (DAA), propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, ethers such as diisopropyl ether, and ethyl acetate And solvents such as esters such as isobutyl acetate, but are not limited thereto.

As a specific example of the production method, the first method is a method carried out in the presence of excess water. In this method, the units of the formulas (3a) and (3b) are mixed with the hydrolyzed silicon compound in a layer substantially containing water as a main component in the unit of the formula (2).
The polyorganosiloxane is condensed to contain 0 mol%. Condensation may be accelerated by aging at room temperature or under heating at 80 ° C. or less, and when using alkoxysilane as a raw material,
The alcohol produced by the hydrolysis or the alcohol and water may be distilled off under reduced pressure of 20 to 100 mmHg to promote the hydrolysis / condensation reaction. The siloxane resin hydrolyzate solution thus obtained may be slightly turbid or turbid in some cases, and this is separated into two layers when left standing. The upper layer is a water-alcohol solution containing 5% by weight or less of a siloxane component, and the lower layer is a viscous siloxane resin containing a small amount of water or alcohol. When it becomes such a high molecular weight number average molecular weight 500 or more, hydrophilic silanol groups are reduced to some extent,
The solubility in water may be reduced and the siloxane resin layer may settle. In this case, after the sediment is separated, an organic solvent may be added to redissolve the precipitate, or it may be extracted and separated with an organic solvent that is hardly soluble in water. The polysiloxane thus obtained can be used by dissolving or diluting it in the above-mentioned organic solvent in addition to water.

The second method is a method performed in the presence of a polar solvent such as alcohol. This process involves reducing the amount of water required for hydrolysis in the presence of the solvent and catalyst from 0.8 to 5%.
The polyorganosiloxane is hydrolyzed with twice the amount of water and condensed until the units of formulas (3a) and (3b) contain 30 to 80 mol% of the units of formula (2). The condensation may be aged at room temperature or under heating at 150 ° C. or lower to promote the reaction, and furthermore, the hydrolysis or condensation reaction may be promoted by distilling off alcohol or alcohol and water. A high molecular weight substance having a number average molecular weight of 500 or more may be added with an organic solvent.

The coating agent of the present invention contains the above-mentioned organopolysiloxane as a main component. If necessary, the following curing catalyst and additives can be optionally added.

The curing catalyst used in the present invention includes lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium methylate, sodium acetate, sodium formate, n-
Hexylamine, tributylamine, diazabicycloundecene, γ-aminopropyltrimethoxysilane, γ
Basic compounds such as -aminopropyltriethoxysilane, N- (β-aminoethyl) aminopropyltrimethoxysilane, γ-aminopropylmethyldiethoxysilane, N- (β-aminoethyl) aminopropylmethyldimethoxysilane; Tetraisopropyl titanate or its homopolymer, tetrabutyl titanate or its homopolymer, aluminum triisobutoxide, aluminum triisopropoxide, aluminum acetylacetonate, aluminum di-n-butoxide monoethyl acetoacetate, aluminum di-acetate
Isopropoxide monoethyl acetoacetate, aluminum perchlorate, cobalt octylate, cobalt acetylacetonate, zinc octylate, zinc acetylacetonate, iron acetylacetonate, tin acetylacetonate, dibutyltin diacetate, dibutyltin dioctylate, dibutyltin Metal-containing compounds such as dilaurylate; and acidic compounds such as p-toluenesulfonic acid and trichloroacetic acid.

These may be used alone or in combination of two or more. The amount used is preferably 0.05 to 5% by weight based on the solid content of the resin.

In addition, organic resins, leveling agents, ultraviolet absorbers, storage stabilizers and the like can be used for the purpose of imparting excellent film performance. For example, metal oxide fine particles such as silica, alumina and titanium oxide (TiO ₂ ) for imparting abrasion resistance, and a buffer for adjusting pH (pH 3 to 6) for imparting stability of silanol groups. Acetic acid and sodium acetate, disodium hydrogen phosphate and citric acid, etc. may be added.

The carrier for electrophotography of the present invention is obtained by coating carrier core particles with a cured product of the above coating composition. In this case, as the carrier core particles used in the present invention, iron powder or ferrite powder is a typical one, but in addition, nickel, a magnetic metal such as cobalt or an oxide thereof, copper, carborundum, glass beads, It can be used by selecting from materials known as carrier core particles such as silicon dioxide.

The particle size of the carrier core particles is 10 to 100.
0 μm, preferably 20 to 300 μm. In the present invention, the above-mentioned coating composition is dissolved in an organic solvent, if necessary, and then applied onto carrier core particles by, for example, a fluidized bed method, an immersion method, a spray method, and the like, and then dried and cured. The thickness of the coating layer is 0.1 to 20 μm
It is preferable that If necessary, overcoating is possible, and depending on the purpose, the components of each layer can be changed and overcoated. The coating composition of the present invention comprises 5
What is necessary is just to heat and harden it at about 0-250 degreeC. In addition,
There is no particular limitation on the toner used with the carrier as a developer, and a toner prepared by dispersing various known synthetic dyes in a wide range of materials including a natural resin, a modifier combining natural and synthetic resins, and the like may be used. Can be.

[0034]

The organopolysiloxane as a main component of the coating composition of the present invention is a heat condensation-curable type of silanol, and has a stable charge amount without being affected by an atmosphere during cooling. Since it has a structure with a high content, it has the characteristics that it can be cured at a lower temperature, has better drying properties, has higher hardness and is more flexible than conventionally known silicones. By using this organopolysiloxane as a main component of a coating agent for an electrophotographic carrier, it has excellent drying properties, does not cause blocking, has a high charge level, has no charge-up, and has stable charging characteristics. In addition, durability is excellent because of excellent flexibility,
This has the effect that the adhesion is also good.

[0035]

EXAMPLES Hereinafter, Production Examples, Examples and Comparative Examples will be described.
The present invention is not limited to the following examples.

[Production Example 1] 408 g (3.0 mol) of methyltrimethoxysilane was placed in a flask equipped with a stirrer, a Liebig condenser, a dropping funnel and a thermometer.
At 0 ° C. or lower, 800 g of water was added and mixed well. There, 216 g (12.0 mol) of 0.05N hydrochloric acid aqueous solution was added.
Was added dropwise over 40 minutes to effect hydrolysis. After completion of the dropwise addition, the mixture was stirred at room temperature for 3 hours. Thereafter, methanol produced by the hydrolysis was distilled off under reduced pressure. The solution was cloudy and separated into two layers when allowed to stand. The lower layer becomes insoluble in water, which is the precipitated polysiloxane. To this was added 469 g of methyl isobutyl ketone (MIBK), and the precipitated polysiloxane was completely dissolved in MIBK. Water layer and MIBK
After separating the aqueous layer, the lower aqueous layer was removed, and the solid content was 30.2%.
668 g of a weight-% (105 ° C./3 hr) colorless and transparent silicone solution (A) was obtained. The number average molecular weight of the polysiloxane obtained by GPC measurement was 1.8 × 10 ³ , the number average degree of polymerization was 27, and the molecular weight distribution was Mw / Mn = 3.0.

The structure of this polysiloxane was determined by ²⁹ Si nuclear magnetic resonance spectrum ( ²⁹ Si-NMR) and infrared absorption spectrum (IR). First, when ²⁹ Si-NMR of the silicone solution (A) was measured, three broad signals were shown, and these chemical shifts were d = 46.
-48 ppm, d = 54-58 ppm, d = 62-68
ppm, respectively, in formulas (a), (b), and (c).
Attributable to the silicon atom of the structural unit represented by The molar ratio of each structure calculated from each signal intensity ratio is represented by the formula (a): formula (b): formula (c) = 1.9: 41.6: 5.
6.5.

CH_ThreeSi (OX)_TwoO_1/2 … (A) CH_ThreeSi (OX) O_2/2 … (B) CH_ThreeSiO_3/2 ... (c) (X is H or CH_Three)

In order to examine the presence or absence of unhydrolyzed alkoxy groups remaining in the polysiloxane resin, this solution was applied to a NaCl plate and air-dried for 30 minutes to measure the infrared absorption spectrum of a thin film. As a result, broad absorption derived from the silanol group was largely observed around 3200 cm ^-1 . Further, the carbon of the remaining methoxy group
Although absorption due to stretching vibration of hydrogen bonds is observed at around 2840 cm ⁻¹ , no absorption was observed for this polysiloxane. On the other hand, unhydrolyzed residual methoxy groups in the resin were determined by subjecting the resin to thermal cracking under strong alkaline conditions, and measuring the amount of methanol distilled off by gas chromatography. As a result, no methanol was detected and I
No methoxy group-derived peak was observed in the R spectrum, indicating that the residual methoxy group of this resin was below the detection limit.

Accordingly, it was confirmed from this that the average composition formula of the silicone solution (A) was (CH ₃ ) _1.00 Si (OH) _0.45 O _1.28 (100 mol% of the unit of the formula (2), the formula (2) (41.6 mol% of the unit of the formula (3a) in the unit of (1)).

[Production Example 2] Using the same apparatus as in Production Example 1, 408 g (3.0 m) of methyltrimethoxysilane was used as a raw material.
ol) and 90 g of dimethyldimethoxysilane (0.75 m
ol), and the others follow the same formulation as in Production Example 1,
840.0 g of a colorless and transparent silicone solution (B) having a solid content of 29.5% by weight was obtained. The number average molecular weight of the polysiloxane obtained from GPC measurement was 1.5 × 10 ³ ,
The molar ratio of each structure derived from trimethoxysilane is represented by the formula (a):
Formula (b): Formula (c) = 2.2: 39.0: 58.8, and the molar ratio of each structure derived from dimethylsilane is Formula (d): Formula (e) = 1.1: 98.9. there were.

(CH_Three)_TwoSi (OX) O_1/2 ... (d) (CH_Three)_TwoSiO_2/2 ... (e) The residual methoxy group content was below the measurement limit.

From this, it was confirmed that the average composition formula of the silicone solution (B) was (CH ₃ ) _1.20 Si (OH) _0.35 O _1.23 (80 mol% of the unit of the formula (2), the unit of the formula (2) 39 mol% of the unit of the formula (3a) therein.

Production Example 3 Using the same apparatus as in Production Example 1, 408 g of methyltrimethoxysilane (3.0 m
ol) and 183.3 g of diphenyldimethoxysilane
(0.75 mol) in the same manner as in Production Example 1, except that 1165 g of a colorless and transparent silicone solution (C) having a solid content of 30.1% by weight was obtained. The number average molecular weight of the polysiloxane obtained by GPC measurement was 1.6 × 10 ³ , and the molar ratio of each structure derived from trimethoxysilane was represented by Formula (a): Formula (b): Formula (c) = 4. 1: 48.2: 4
7.7, the molar ratio of each structure derived from diphenylsilane was Formula (f): Formula (g) = 4.2: 95.8.

(C₆H_Five)_TwoSi (OX) O_1/2 … (F) (C₆H_Five)_TwoSiO_2/2 ... (g) The residual methoxy group content was below the measurement limit.

From this, the average composition formula of the silicone solution (C) is (CH ₃ ) _0.8 Si (C ₆ H ₅ ) _0.4 Si (OH) _0.46 O
_1.17 (80 mol% of units of formula (2), 48.2 mol% of units of formula (3a) in units of formula (2)).

[Production Example 4] Using the same apparatus as in Production Example 1, 408 g of methyltrimethoxysilane (3.0 m
ol), and 2.0 g of an acidic ion exchange resin (Purolite CT-169) and 100 g of methanol were added.
Mix well. Then, 162 g of ion-exchanged water was added to 30
The mixture was added dropwise in minutes, and hydrolysis was performed. After completion of the dropwise addition, the mixture was stirred under methanol reflux for 5 hours. After cooling, the ion exchange resin was removed by filtration, and the solid content was 30.8% by weight (1%).
655 g of a colorless and transparent silicone solution (D) having a temperature of 05 ° C./3 hr) was obtained. The number average molecular weight of the polysiloxane obtained by GPC measurement was 1.4 × 10 ³ , and the molar ratio of each structure derived from trimethoxysilane was represented by the formula (a): formula (b): formula (c) = 6. 0: 57.9: 36.1.

The amount of residual methoxy groups was 4.6% by weight.

From this, it was confirmed that the average composition formula of the silicone solution (D) was (CH ₃ ) _1.0 Si (OH) _0.59 (OCH ₃ ) _0.11 O _1.15 (100 mol% of the formula (2), (Total of 57.9 mol% of the unit of the formula (3a) and the unit of the formula (3b) in the unit of (2)).

[Production Example 5] Using the same apparatus as in Production Example 1, 367 g of methyltrimethoxysilane (2.7 m
ol), trifluoropropyltrimethoxysilane 6
5.4 g (0.3 mol) was added, and 2.3 g of an acidic ion exchange resin (Purolite CT-169) and 158 g of methanol were added and mixed well. Thereto, 162 g of ion-exchanged water was added dropwise over 30 minutes, and hydrolysis was performed. After completion of the dropwise addition, the mixture was stirred under methanol reflux for 5 hours. After cooling, the ion exchange resin was removed by filtration to obtain 741 g of a colorless and transparent silicone solution (E) having a solid content of 31.1% by weight (105 ° C./3 hr). The number average molecular weight of the polysiloxane obtained by GPC measurement was 1.7 × 10 ³
And the molar ratio of each structure derived from trimethoxysilane is represented by the following formula (a): formula (b): formula (c) = 3.1: 52.2: 4
4.7, the molar ratio of each structure derived from trifluoropropylsilane is as follows: Formula (h): Formula (i): Formula (j) = 35.2: 5
6.6: 8.2 (100 mol% of the unit of the formula (2), the unit of the formula (3a) in the unit of the formula (2) and the formula (3)
b) a total of 52.2 mol% of units).

[0051] CF_ThreeCH_TwoCH_TwoSi (OX)_TwoO_1/2 … (H) CF_ThreeCH_TwoCH_TwoSi (OX) O_2/2 ... (i) CF_ThreeCH_TwoCH_TwoSiO_3/2 ... (j) The residual methoxy group content was 5.1% by weight.

From this, the average composition formula of the silicone solution (E) is (CH ₃ ) _0.9 (CF ₃ CH ₂ CH ₂ ) _0.1 Si (OH) _0.51
Accepted (OCH ₃₎ is _0.14 O _1.18.

[Comparative Production Example 1] In the same apparatus as in Production Example 1, 408 g of methyltrimethoxysilane was placed in a flask.
(3.0 mol) and toluene at 15 ° C. or less.
4.7 g and methanesulfonic acid 10.1 g were added and mixed well. Thereto, 97.2 g of water was added dropwise over 60 minutes to carry out hydrolysis. After completion of the dropwise addition, the mixture was stirred at room temperature for 5 hours.
After neutralizing methanesulfonic acid, methanol generated by hydrolysis was distilled off. After washing with water and dehydration, 478 g of a colorless and transparent silicone solution (F) having a solid content of 40.0% by weight (105 ° C./3 hr) was obtained. The number average molecular weight of the polysiloxane obtained by GPC measurement was 1.9 × 10 ³ , and the molar ratio of each structure derived from trimethoxysilane was represented by the following formula (a): formula (b): formula (c) = 0. 4: 27.4: 72.2.

The amount of residual methoxy groups was 4.2% by weight.

From this, it was recognized that the average composition formula of the silicone solution (F) was (CH ₃ ) _1.0 Si (OH) _0.18 (OCH ₃ ) _0.10 O _1.36 (100 mol% of the unit of the formula (2), (27.4 mol% in total of the unit of the formula (3a) and the unit of the formula (3b) in the unit of (2)).

[Comparative Production Example 2] Silicone solution (F) 1
00 parts, 12 parts of methyltris (methylethylketoxime) silane, 0.4 part of a 50% xylene solution of dibutyltin dioctoate, and a volatile solvent are added so as to have a nonvolatile content of 25%. A silicone solution (G) was obtained.

Comparative Production Example 3 Using the same apparatus as in Production Example 1, 408 g (3.0 mol) of methyltrimethoxysilane was used.
l), 200 g of methanol was added and mixed well. 1
At 0 ° C. or lower, 216 g of a 0.05N hydrochloric acid aqueous solution was added dropwise over 30 minutes to carry out hydrolysis. After completion of the dropwise addition, the mixture was stirred at 10 ° C. or lower for 40 minutes and at room temperature for 6 hours. After cooling, the mixture was filtered to obtain 811 g of a colorless and transparent silicone solution (H) having a solid content of 23.8% by weight (105 ° C./3 hr). The number average molecular weight of the polysiloxane obtained by GPC measurement was 420, and the molar ratio of each structure derived from trimethoxysilane was represented by the following formula (a): formula (b): formula (c) = 4.8: 53.5. : 4
1.5.

The residual methoxy group content was 2.5% by weight.

From this, it was confirmed that the average composition formula of the silicone solution (H) was (CH ₃ ) _1.0 Si (OH) _0.57 (OCH ₃ ) _0.06 O _1.19 (100 mol% of the unit of the formula (2), (Total of 53.5 mol% of the unit of the formula (3a) and the unit of the formula (3b) in the unit of (2)). This solution had poor stability and gelled after one month.

Examples and Comparative Examples The silicone solutions (A) to (H) obtained in the above Production Examples were adjusted to 2% using a diluent as shown in Table 1. The solution was applied as carrier core particles at 90 ° C. for 30 minutes using a 1 kg fluidized bed of ferrite having an average particle size of 100 μm. Then 200 ° C
For 30 minutes to prepare a carrier material. Table 2 shows the results of the state (blocking) during coating and heating.

In 95 parts of the carrier material, a positively charged toner (toner (black), Vision 450, manufactured by Fuji Xerox Co., Ltd.) is used.
Add 5 parts and shake in a poly bottle (vibration width 50 mm,
After charging at a shaking speed of 200 times / min), the charge amount of the toner was measured with a blow-off powder charge meter (manufactured by Toshiba Chemical Corporation). Table 3 shows the results.

[0062]

[Table 1]

[0063]

[Table 2]

[0064]

[Table 3]

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masaaki Yamaya 1-10 Hitomi, Matsuida-machi, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Technology Laboratory (56) References JP-A-2-73372 ( JP, A) JP-A-5-88413 (JP, A) JP-A-2-33159 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 9/113

Claims (3)

(57) [Claims] 1. The following average composition formula (1): R¹ _aSi (OH)_b(X¹)_cO_{(4-abc) / 2} (1) (where R¹Is also a hydrogen atom or an unsubstituted group having 1 to 18 carbon atoms
Or two or more selected from substituted monovalent hydrocarbon groups
The above group, X¹Represents a hydrolyzable group, and a, b, and c represent
0.6 ≦ a ≦ 1.8, 0.2 ≦ b ≦ 0.8, 0 ≦ c ≦
0.5, 0.8 ≦ a + b + c ≦ 2.0
You. ) And the following general formula (2):¹ Si (OH)_d(X¹)_eO_{(3-de) / 2} (2) (where R¹And X¹Has the same meaning as above, and d and e
Are 0, 1 or 2 respectively, and d + e = 0, 1 or
Is an integer satisfying 2. ) Is 3
0-100 mol%, and the structure of the formula (2)
The unit is the following general formulas (3a) and (3b):¹Si (OH) O_2/2 (3a) R¹Six¹O_2/2 (3b) (wherein, R¹And X¹Has the same meaning as described above. )
Containing a total of 30 to 80 mol% of the structural unit
Organopolysiloxane having an average molecular weight of 500 or more
An electrophotographic carrier coating characterized by being a main component.
Ting agent. 2. In the formula (1), the value of b is 0.25 ≦
2. The coating agent according to claim 1, wherein b ≦ 0.6. 3. A carrier for electrophotography, wherein carrier core particles are coated with a cured product of the coating agent according to claim 1.