JPH02103563A - Electrostatic charge developing carrier - Google Patents

Abstract

PURPOSE:To enhance adhesion of a polymer with a carrier core, and durability and electrostatic chargeability by coating the core with the copolymer of a combination of a monomer of tetrafluoroethylene, trifluoroethylene, or the like and a specified monomer or a composition containing said copolymer. CONSTITUTION:The carrier core is coated with the copolymer of the 50-95mol% monomer selected from a group composed of tetrafluoroethylene, trifluoroetnyldne or the like, and the 50-5mol% monomer represented by formula I in which R1 is 1-20 C alkyl or phenyl; R2 is methyl, ethyl, or the like; and (m) is 0 or an integer of 1-3, or a composition containing said polymer, thus permitting the coating layer of the carrier made of said copolymer to be supe rior in film strength and adhesion to the core material, and consequently, to be excellent in durability and to give high chargeability to the carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostatic charge developing carrier (hereinafter simply referred to as carrier) which constitutes an electrostatic charge image developer together with a toner in an electrophotographic copying machine.

Prior art and its problems Carriers in which a carrier core is coated with a fluorine-containing polymer are known (Japanese Patent Application Laid-Open No. 48-52239, JP-A No. 49-123037, and JP-A No. 59-53).
Publication No. 875). However, these polymers have
There is a problem in that the adhesion to the carrier core material is low.

In order to improve adhesion, it has been proposed to use a hydroxyl group-containing copolymer crosslinked with isocyanate, melamine, etc. (JP-A-59-53875, JP-A-60-59369, etc.) ), in these polymers, crosslinking may not proceed completely, so unreacted hydroxyl groups, isocyanates, etc. may remain, which may deteriorate charging characteristics.

Means for Solving the Problems As a result of repeated research in view of the problems of the prior art as described above, the present inventor has discovered that a copolymer made of a specific combination of monomers has excellent properties as a carrier film. I found out that it works.

That is, the present invention provides a carrier for electrostatic charge development comprising a coating layer made of the following copolymers: ■ (a) Tetrafluoroethylene, trifluoroethylene, talolotrifluoroethylene, and hexafluoropropylene. (b) (OR2) 3-.

(R+ represents an alkyl group having 1 to 20 carbon atoms or a phenyl group; R2 represents a methyl group, ethyl group, propyl group, or acetyl group; m is 0 or an integer of 1 to 3) A carrier for electrostatic charge development coated with a polymer containing a small amount of a monomer (50 to 5 mol% of one type of monomer or a composition containing the polymer) (hereinafter referred to as the first invention of the present application)
.

■ (a) 50 to 95 mol% of at least one monomer selected from the group consisting of tetrafluoroethylene, trifluoroethylene, tarolotrifluoroethylene, and hexafluoropropylene, and (b) (OR2) 3-1II (R+ is , represents an alkyl group or phenyl group having 1 to 20 carbon atoms; R2 represents a methyl group, ethyl group, propyl group or acetyl group; m is 0 or an integer of 1 to 3). 110 to 99% by weight of a polymer containing 50 to 5 mol% of at least one type; and (C) CH2=C(X)COORf (X represents hydrogen, fluorine or a methyl group; Rr is
70 to 99 mol% of at least one monomer represented by (representing a fluoroalkyl group), and (d) (OR3)3-p (X is the same as above; R3 represents a methyl group, ethyl group, or propyl group) ; p is 0, 1 or 2); p is 0, 1 or 2); p is 0, 1 or 2; (referred to as the second invention).

In addition, the alkyl group referred to in the present invention refers to linear, branched,
It may be cyclic, and also includes halogenated alkyl groups substituted with fluorine, chlorine, and bromine.

In the first invention of the present application and the second invention of the present application, specific examples of the monomer (OR2-m) used as the component (b) include the following.

C1(-CH81(OC2H5)3 CI+2- CH31(OCHs) 2CH-CH8
i(CH3)2 CH-CH31(OCH3) (C112C112CF3)2 The monomer composition ratio in copolymer I used as a coating material for an electrostatic charge carrier in the first invention of the present application is monomer (a)/monomer (b). =50-95150-5 (molar ratio), more preferably 50-60150-40 (
molar ratio). Its molecular weight is about 0.1 to 1.0, which has an intrinsic viscosity [η] of methyl ethyl ketone as a solvent at 35°C.

When the monomer (a) is less than 50 mol%, the fluorine content decreases and the amount of charge when used as a carrier is insufficient, whereas when it exceeds 95 mol%, the core material This is not preferable because the adhesion with the material decreases, resulting in poor durability.

In the first invention of the present application, at least one of the following monomers can be used in combination as the third copolymer component constituting the copolymer (1) in an amount not exceeding 40 mol% of the copolymer (I).

Vinyl ethers: methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, chloroethyl vinyl ether, cyclohexyl vinyl ether, etc.

Vinyl esters: vinyl acetate, vinyl benzoate, vinyl versatate, vinyl trichloroacetate, etc.

(Meth)acrylic monomers; methyl acrylate, methyl methacrylate, cyclohexyl methacrylate, etc.

Others: ethylene, propylene, vinyl chloride, vinylidene chloride, etc.

Fluorine-containing monomer: CH2-CH0CH2(CF20F2)11 copolymer I
Preferred specific examples are as follows.

l-1 CH3S 1OcH3 CH3S 1OCH3 C2H5S i C2H5 CH30S 1OCH3 OCH2CF2CF2H OCH6 -O CH3 In the second invention of the present application, in order to increase the charge rise and chargeability of the carrier, monomer (C) represented by the formula and formula % A copolymer (1) with a monomer (d) represented by the formula (%) is used by mixing with the copolymer weight.

Specific examples of the monomer (C) include the following.

CH2-CHCOOCH2CF CH2-mCFC00CH2CF3 CH2-C(CH3)COOCH2CF3CH2-CH
COOCH, 2CH2CF20CF2-C(CH3)C
OOCH2CF3CF,, HCl2-CHCOOCH2
CF2CF3CH2=CCICOOCH2CF2 CF
3CH2””C(CH3)COOCH2CF2 CF3
CH2=CHC00C(CH3)2 CF2 CH2C
F2-C(CH3)C00C(CH3)2 cF2cF
2HCH2-CHCOOCH2CF2CFHCF3CH
2-C(CH3)COOCH2CF2 CFHCF3C
H2=CFCOOCH2(CF2 CF2)2 HCl
2 =C(CH3)COOCH2(CF2 CF2)2
HCl2-CHCOOCH2C(CF3)2 HCl
2-C(CH3)COOCH2C(CF3)2HCl
2 =CHCOOCH2CH2(CF2)7 CF3C
H2-C(CH3) COOCH2CH2(CF2
)y CF 3H2 CF2 CF3 CF3 CF3 CF3 CF3 CF3 CF3 CF.

F2 = CHCOOCH2CH2 (CF2 )7 CF (C
F3)2-C(CH3)COOCH2CH2(CF2
)7 CF (CF3)30CF2CF2CH20
COCH-CH20CF2 CF2 CH20COC(
CH3)-CH2CF20CF2 CF2CH20CO
CH-CH2CF20CF2 CF2 CH20COC
(CH3)-CH2(CF2)20CF2 CF2 C
H20COCH-CH2(CF2)2QCF
2 CF 2 CH20COC(CH3) -CH2(
CF2 )30CF2 CF2 CH20COCH-C
H2(CF2)30CF2 CF2 CH20COC(
CH3)-CH2CF2 CF2-CF2 CF3 CF3 F2 F2 F2 F2 CF.

CF3 CH20CH2CH20COCH-CH2CH20CH
2ca2ococ (CH3')-CH2HCF20C
H2CH20COCH-CH2HCF20CH2CH2
0COC(CH3)-CH2HCF2 (OCH2C
H2) OCOCH-CH2HCF2 (OCH2CH
2) OCOC(CH3)=CH2CF2CF2CH20
CH20COCH-CH2CF2 CF2 CH20C
H2CH20COC(CH3)-CH2 monomer (d)
Specific examples include the following.

CH2=CHCOOCH2Si (OCH3)3CH2
=C(CHi)COOCH2Sl (OCH3)3C
H2-CHCOOCH2CH2S i (OCH3)
3CH2=C(CH3)COOCH2CH2Si (O
CH3)3CH2=CHCOOCH2CH2CH2Si
(OCH3)3CH2-C(CH3)COOCH2C
H2CH2Si (OCH3)3CH2=CFCOO
CH2CH2CH2S t (OCH3)3CH2-
CCJCOOCIh CH2CH2Si (OCH3)
3CH2-C(CH3)COOCH2CH2Si (O
CH2CH3)3CH2-C(CH3)COOCH2C
H2CH2Si (CH3) (OCH3)2CH2=C
FCOOCH2CH2CH2Si (OCH2CH20
CH3) 3 In the second invention of the present application, is the monomer composition ratio in the copolymer (■) blended with the copolymer (■) used?
-(c)/monomer -(d) = 70-99/1
-30 (molar ratio), more preferably 90-99/
1 to 10 (molar ratio). Its molecular weight is approximately 0.1 to 1.5 in intrinsic viscosity [η) at 35° C. and in the solvent methyl ethyl ketone or m-xylene hexafluoride. If the amount of the monomer (C) is less than 1 mol %, the adhesion to the core material and the crosslinkability with the copolymer (2) will be insufficient, resulting in poor durability of the carrier. On the other hand, if the amount of the monomer (C) exceeds 30 mol %, the chargeability of the copolymer decreases and the performance of the carrier becomes insufficient.

The copolymer H used in the second invention of the present application may contain, for example, up to 30% of (meth)acrylic monomer, styrene, vinylidene chloride, within a range that does not impair its properties.
Monomers such as ethylene and propylene may be copolymerized.

Preferred specific examples of copolymer H are as follows.

l-2 (OC2Hs) 2 The production of the carrier of the present invention, that is, the coating on the carrier core material, is carried out in substantially the same manner as a conventional method. That is, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; acetate ester solvents such as ethyl acetate, cellosolve acetate, and n-butyl acetate; tetrahydrofuran, dioxane, dimethylformamide, dimethylacetamide, chloroform, 1,1.1-1 The above copolymer I or
may be applied to the surface of the carrier core material by any known method, and if necessary, heat treatment may be performed at a temperature of up to 150° C. after film formation.

From the viewpoint of evaporation rate, etc., the solvent should have a boiling point of 80 to 1
It is more preferable to use a temperature of about 40°C.

As the carrier core material used in the present invention, all known materials can be used, and there are no particular limitations. Specifically, metals such as iron, cobalt, and nickel; alloys such as ferrite, magnetite, and Mn-Cu-AJSMn-Cu-3n; and metal oxides such as CrO2 are exemplified.

Effects of the Invention The coating layer of the carrier made of the copolymer used in the present invention has excellent film strength and good adhesion to the core material, so it not only has excellent durability but also has a stable and high chargeability on the carrier. give.

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention.

Examples 1 to 7 Copolymers I shown above I-1 to I-4 alone or n
Acetone-methyl ethyl ketone-isopropanol (45/4
After dissolving the coating solution in a mixed solvent of 5/10 (weight ratio) to a concentration of 2%, spherical iron powder (trademark "DSP") was added as a carrier core material by a fluid spray method according to a conventional method
135C'' (manufactured by Dowa Iron Powder Industries Co., Ltd.) with a film thickness of 2.
Seven types of μm carriers were obtained.

Table 1 shows details of the copolymers used in each example.

1st Copolymer I (polymerization part) table Copolymer■ (Junior N Department) Example 1 1-1:to.

2, I-1: 50 11-1:
503 I-1: 70 ll-
1: 304 I-2: 100 5 I-2: eo ll-2:
406 I-3:100 7 I-4: go ll-1:
20 Comparative Example 1 Chlorotrifluoroethylene/alkyl vinyl ether/hydroxyl group-containing vinyl ether (trademark "Lumiflon LF2")
00'', manufactured by Asahikawako Co., Ltd.) was dissolved in xylene to a concentration of 2%, and the isocyanate was OH/NGO = 1/1.
．． 1 (molar ratio), and using this as a coating liquid, a carrier was obtained in the same manner as in Example 1.

Test Example 1 After stirring each of the carriers obtained in Examples 1 to 7 and Comparative Example 1 for 100 hours in a ball mill, the film peeling resistance was determined by comparing the amount of elution of the film before and after stirring.

The results are shown in Table 2.

The criteria for determining film peeling resistance are as follows.

◎... No film peeling O... Film peeling less than 5% △... Film peeling 5-10% ×... Film peeling 10% or more It is clear that the film has excellent film strength and good adhesion.

Test Example 2 Polystyrene resin (trademark “Picolastic D135”)
Shell Standard Oil Co., Ltd.) 100T 1 part,
10 parts by weight of a toner with an average particle size of 10 μm, which is a mixture of 5 parts by weight of "Biares 155°" (manufactured by Columbia Ribbon and Manufacturing Co., Ltd.) and 5 parts by weight of "Oil Black BW" (manufactured by Orient Chemical Industry Co., Ltd.); 100 parts by weight of the copolymers obtained in each of Examples 1 to 7 and Comparative Example 1 were mixed, and the toner charge amount was measured by a blow-off method.The results are shown in Table 3.

Carrier Table 3 Toner charge amount Q/M (μc/g) +20 +28 +25 +18 +27 +27 +24 +3 As is clear from the results shown in Table 3, in the carrier of the present invention using a specific copolymer, the toner charge Quantity is high.

On the other hand, in the case of the carrier according to the comparative example, The amount of charge is extremely low.

(Hereafter Up)

Claims (1)

[Scope of Claims] [1] (a) 50 to 95 mol% of at least one monomer selected from the group consisting of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene; and (b) ▲ Formula , chemical formulas, tables, etc.▼ (R_1 represents an alkyl group having 1 to 20 carbon atoms or a phenyl group; R_2 represents a methyl group, ethyl group, propyl group, or acetyl group; m is 0 or 1 to at least one monomer represented by (an integer of 3) from 50 to
A carrier for electrostatic charge development coated with a polymer containing 5 mol % or a composition containing the polymer. [2] (a) 50 to 95 mol% of at least one monomer selected from the group consisting of tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, and hexafluoropropylene, and (b) ▲ mathematical formula, chemical formula, table, etc. ▼ (R_1 represents an alkyl group having 1 to 20 carbon atoms or a phenyl group; R_2 represents a methyl group, ethyl group, propyl group, or acetyl group; m is 0 or an integer of 1 to 3 ) At least one monomer represented by 50 to
(c) CH_2=C(X)COOR_f (X represents hydrogen, fluorine or a methyl group; R_f represents a fluoroalkyl group) 70 to 99 mol% of at least one kind of monomer, and (d) ▲ Numerical formula, chemical formula, table, etc. ▼ (X is the same as above; R_3 represents a methyl group, ethyl group, or propyl group; n is 1 90 to 1% by weight of a polymer II containing 1 to 30 mol% of at least one monomer represented by: an integer of ~4; p is 0, 1 or 2)
A carrier for electrostatic charge development coated with a mixture consisting of.