JP3411175B2 - Resin composition for toner and toner - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for a toner used in electrophotography and the like, and more specifically, a toner used in a dry developing method of the methods for developing an electrostatic image. Resin composition and toner.

[0002]

2. Description of the Related Art A dry developing system is often used as a system for developing an electrostatic charge image in electrophotography or the like. In this dry development method, a triboelectric chargeable toner is prepared by mixing a carrier such as iron powder or glass beads with a fine powder containing a colorant such as carbon black or other additives in a resin composition for toner serving as a binder ( A developer) is used.

In order to obtain a copy by the above-mentioned dry development method, usually, an electrostatic latent image is formed on a photoreceptor, and a triboelectrically chargeable toner is electrically adhered thereto to form a toner image, This toner image is transferred onto a sheet such as a sheet of paper, and the toner image is fixed by a hot pressing roller having releasability to the toner to form a permanent visible image.

The basic performance of the above toner is offset resistance (the toner adheres to a hot pressing roller for fixing,
It is required that the paper does not stain the paper), the fixability (the toner adheres strongly to the paper), and the blocking resistance (the toner particles do not aggregate). In particular, a toner having a wide fixing temperature range and excellent in offset resistance is required.

In response to such a request, Japanese Patent Laid-Open No. 56-1
Japanese Patent Laid-Open No. 58340 proposes a method of broadening the molecular weight distribution of a resin by using a low molecular weight component and a high molecular weight component. By this method, it is possible to obtain an excellent offset resistance, fixing property, and blocking resistance, but in order to further improve the fixing property in response to the recent demand for low temperature fixing, the offset resistance is It was difficult to balance the property and the blocking resistance.

On the other hand, measures have been taken to lower the softening point by lowering the molecular weight of the resin, or to narrow the molecular weight distribution of the resin to sharpen the melting behavior, but the cohesive force of the toner is taken. Was insufficient, sufficient fixing strength (fixed image strength) was not obtained, and it was also difficult to achieve both offset resistance and blocking resistance.

Further, a method of adding a low melting point crystalline compound to a resin component for fixing at a low temperature is known, but bleeding out occurs due to its low viscosity, and toner and paper are fixed at the time of fixing. There is a problem that the toner is deposited on the interface to lower the fixing strength or the blocking resistance of the toner is lowered. As a solution to this problem, a method has been proposed in which a low melting point crystalline compound is chemically grafted or slightly crosslinked to a binder resin (binder resin) (Japanese Patent Laid-Open No. 7-64).
No. 323, JP-A-5-323664, etc.).

However, in the above method, since the low melting point crystalline compound is chemically bonded to the binder resin (binder resin), the glass transition point (Tg) of the binder resin is lowered and the toner is fixed. There is a problem in that it is difficult to balance both the storage property and the storability.

[0009]

SUMMARY OF THE INVENTION The present invention is to solve the problems of the above-mentioned conventional toners, and its object is to fix at low temperature, anti-offset property, anti-blocking property, and storage stability. (EN) Provided are a resin composition for toner, which is excellent in fixing property and a fixing strength, and a toner which uses the resin composition for toner.

[0010]

A resin composition for a toner of the present invention comprises a vinyl-based copolymer having a styrene-based monomer and a (meth) acrylic acid ester-based monomer as constitutional units, and a terminal copolymer. A resin composition for a toner, which comprises a low melting point crystalline compound having -OH as a polar group as a main component, wherein the vinyl-based copolymer has a low molecular weight of 3,000 to 50,000 as a weight average molecular weight (Mw). Combined component and weight average molecular weight (Mw) 100,000-5
The resin composition for a toner, which comprises 1,000,000 to 30% by weight of a component having a high molecular weight polymer component of, 000,000 and having -OH or a halogen group as a polar group in the vinyl-based copolymer. Contains 1 to 30% by weight of a low melting point crystalline compound having —OH as a polar group at the terminal, and has a shear fracture energy per unit area of 100 to 2,000.
It is characterized by being N / m.

The vinyl copolymer used in the present invention comprises a styrene monomer and a (meth) acrylic acid ester monomer as constitutional units.

Examples of the styrene-based monomer include
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-
Dodecyl styrene, p-methoxy styrene, p-phenyl styrene, etc. are mentioned, and styrene is preferable among these.

Examples of the (meth) acrylic acid ester type monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
N-Butyl (meth) acrylate, isobutyl (meth) acrylate, n-octyl (meth) acrylate, (meth)
Dodecyl acrylate, 2-ethylhexyl acrylate,
In addition to (meth) acrylic acid esters such as stearyl acrylate, phenyl (meth) acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, bisglycidyl methacrylate, polyethylene glycol dimethacrylate, methacryloxyethyl phosphate And the like. Among these, methyl methacrylate, (meth) acrylic acid n
-Butyl, 2-ethylhexyl acrylate are preferred.

The vinyl copolymer comprises a low molecular weight polymer component and a high molecular weight polymer component, and the low molecular weight polymer component has a weight average molecular weight (Mw) of 3,000 to 50,000 and a high molecular weight polymer component. Has a weight average molecular weight (Mw) of 100,000 to 500.
In many cases.

When the weight average molecular weight (Mw) of the low molecular weight polymer component is less than 3,000, the glass transition point (Tg) is low.
The blocking resistance of the resin composition decreases due to the decrease of
If it exceeds 50,000, the low-temperature fixability of the resin composition will deteriorate. Also, the weight average molecular weight (Mw) of the above high molecular weight polymer component
However, when it is less than 100,000, the melt viscosity of the resin composition is lowered and the offset resistance is lowered, and when it exceeds 5 million, the fixability of the resin composition is lowered.

The vinyl-based copolymer has a polar group and
And contains 1 to 30% by weight of a component having -OH or a halogen group . The content of the component having a polar group is 1% by weight
If the amount is less than 30% by weight, the interaction with the low-melting-point crystalline compound described below is lowered, the low-melting-point crystalline compound is easily bleed out, the blocking resistance and the fixing strength are lowered,
When it is more, the cohesive force between the vinyl-based copolymers increases and the low-temperature fixability of the resin composition decreases.

The polar group-containing component may be present in either the high molecular weight polymer component or the low molecular weight polymer component, or in both of them. The component having a polar group is obtained by polymerizing a monomer having a polar group in two steps, for example, using a polymerization initiator having two radical decomposition temperatures. To be

Examples of the monomer having the polar group, for example if <br/>, click Roroechiren, halogenated ethylene such as tetrafluoroethylene; halogenated styrene derivatives p- chloromethylstyrene, p- chlorostyrene and the like; p- hydroxymethylstyrene, 2-(p- vinylphenyl) hydroxylated styrene derivatives such as ethanol; click Roroechiru <br/> (meth) acrylate, beta-hydroxy ethyl (meth)
Acrylate, N chromatography (2-hydroxyethyl) acrylate <br/> Ami de, chloro acryloxypropyl Nitrile Le and the like.

The low-melting crystalline compounds used in the present invention are those having a polar group at the end, as the polar group, preparative toner charge amount of easy control, the ease of synthesis - Limited to those containing OH (hydroxyl group).

The low melting point crystalline compound has a melting point of 5
Compounds at 0-130 ° C are preferred. If the melting point is less than 50 ° C, the storage stability may decrease, and the melting point is 130 ° C.
If it is higher than the above range, the low temperature fixability may be deteriorated.

Examples of the low melting point crystalline compound include the following low molecular weight crystalline compounds and crystalline polymers.
Specific examples of the low molecular weight crystalline compound include, for example,
1-hexadecanol, 1-heptadecanol, stearyl alcohol, 1-nonadecanol, 1-eicosanol, 1-
Docosanol, 1-Torikosanoru, 1-tetracosanol, include higher alcohol such as glyceryl alcohol.

Specific examples of the above crystalline polymer include ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol,
Polycondensation of polyols such as 1,6-hexanediol, hexamethylene glycol and tetramethylene glycol with polybasic acids such as fumaric acid, maleic acid, itaconic acid, terephthalic acid, succinic acid, adipic acid and sebacic acid Polyesters obtained; polyethylene glycol,
Polyethers such as polypropylene glycol; polymers including long-chain alkyl esters such as behenyl acrylate, behenyl methacrylate, behenyl itaconate, and stearyl itaconate as main polymerization units.

The content of the low melting point crystalline compound is 1 to 30% by weight in the resin composition. When the content of the low melting point crystalline compound is less than 1% by weight, the crystallinity of the entire resin composition is lowered to lower the low temperature fixability, and when it exceeds 30% by weight, the resin composition is plasticized to be stable in storage. Sex decreases.

The toner resin composition of the present invention contains the above vinyl-based copolymer in an amount not detrimental to the object of the present invention.
Monomers such as vinyl acetate, vinyl chloride and ethylene may be copolymerized, and polymers of these monomers may be mixed. Further, the resin composition for a toner includes a polyester resin, an epoxy resin, an aliphatic amide,
Bis fatty acid amide, metal soap, paraffin and the like may be mixed.

When the shear fracture energy per unit area of the toner resin composition is small, the cohesive force of the resin composition is small and sufficient fixing strength cannot be obtained, and when it is large, the pulverizing performance during toner production is deteriorated. However, since it becomes difficult to obtain a toner having a small particle diameter, it is limited to 100 to 2,000 N / m.

Further, when the shear fracture energy per unit area of the low melting point crystalline compound becomes small, high fixing strength cannot be obtained, and when it becomes large, the cohesive force of the resin composition becomes too large and the pulverizing performance at the time of toner production is increased. Is decreased, and it becomes difficult to obtain a toner having a small particle size.
It is preferably N / m.

The shear fracture energy per unit area of the resin composition for toner and the low melting point crystalline compound is measured by the following method. First, a 1 cm × 5 cm rectangular sample is prepared using an 80 mesh stainless steel mesh. Then, as shown in FIG.
The mesh portions were sufficiently impregnated with 0.2 g of the resin composition for toner (or low melting point crystalline compound) C heated and melted, and the tip portions of the samples A and B were overlapped with each other. A test piece D is produced by laminating so that the margin is about 1 cm × 1 cm.

The test piece is subjected to a tensile shear strength test in the arrow direction using a tensile tester to measure the breaking energy. The value obtained by dividing this breaking energy by the adhesive area is taken as the shear breaking energy per unit area. The test conditions were: chuck distance 30 mm, tensile speed 10 mm /
The temperature is 23 ° C. for minutes.

The toner resin composition of the present invention is, for example,
It can be produced by adding the above-mentioned other components to the vinyl-based copolymer and the low-melting-point crystalline compound, if necessary, mixing them, and melt-kneading them with a roll mill, a kneader, an extruder or the like.

In the toner of the present invention, for example, the resin composition for a toner obtained above is mixed with a charge control agent, a colorant, and other additives, and this is melt-kneaded by a roll mill, a kneader, an extruder or the like. To do. After cooling, finely pulverize using a pulverizer such as a jet mill, and if necessary, classify to a particle size of 5
The toner particles are 20 μm.

The above-mentioned other additives are additives which are added as required, and examples thereof include a release agent and magnetic fine particles.

Examples of the colorant include carbon black, chrome yellow, aniline blue and the like. Examples of the charge control agent include nigrosine,
Examples include dyes such as spirone black and phthalocyanine-based pigments. Examples of the release agent include low molecular weight polyethylene and polypropylene wax. Examples of the magnetic fine particles include fine powders of metals such as nickel, manganese, iron, cobalt and chromium, various ferrites and various alloys.

To the toner thus obtained, a fluidizing agent may be added later in order to enhance the fluidity as a powder. Examples of the fluidizing agent include hydrophobic silica powder, acrylic resin powder, fluorine resin powder, and higher fatty acid metal salt powder.

[0034]

In the resin composition for a toner of the present invention, the low molecular weight polymer component and the high molecular weight polymer component and the low melting point crystalline compound interact with each other due to intermolecular force such as hydrogen bond between polar groups. , Is pseudo-grafted to have an aggregated structure.
This aggregate structure prevents the low melting point crystalline compound from bleeding out, and the glass transition point (T
g) does not decrease, and the blocking resistance of the obtained toner is
The fixability and offset resistance (especially at low temperatures) are improved.

The fixing strength is related to the strength of the solid toner and can be evaluated by the shear fracture energy per unit area. Since the shear breaking energy per unit area of the resin composition for toner is 100 to 2,000 N / m, sufficient fixing strength can be obtained. Further, the fixing strength is also related to the strength of the low melting point crystalline compound contained therein, and the shear fracture energy per unit area is 100 to 5,000.
By using a low melting point crystalline compound having 0 N / m, a toner having higher fixing strength can be obtained.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION Examples and comparative examples of the present invention will be described below. (Example 1) Toluene 720 was placed in a 3 L (liter) separable flask.
g, styrene / n-butyl acrylate / methyl methacrylate (St-BA) having a weight average molecular weight of 1,000,000.
-MMA) 120 g of copolymer and 60 g of behenyl alcohol as a low melting point crystalline compound were added and dissolved. After replacing the gas phase with nitrogen gas, the system was heated to the reflux temperature of toluene. Then, with stirring in a state of refluxing toluene occurs, beta-hydroxyethyl methacrylate acrylate 60g as a component having a polar group, and Perhexa MC (manufactured by NOF Corporation, a two-stage decomposition type polymerization initiator) as a polymerization initiator 35g Was added dropwise over 1 hour, then 360 g of styrene and 36 g of n-butyl acrylate were added.
and 24 g of methyl methacrylate were added dropwise over 1.5 hours to carry out solution polymerization. After completion of dropping, after aging for 30 minutes while stirring at the reflux temperature of toluene,
While gradually raising the oil bath temperature to 150 ° C., the toluene was removed under reduced pressure to obtain a resin. After cooling the resin, ground to β- hydroxyethyl meth acrylate to obtain toner resin composition which is copolymerized blockwise.

100 parts by weight of this resin composition for toner, 5 parts by weight of carbon black ("MA-100" manufactured by Mitsubishi Chemical Co., Ltd.), and Spiron Black ("TRH" manufactured by Hodogaya Chemical Co., Ltd.)
About 1 part by weight and 3 parts by weight of PP wax (“Viscor 660P” manufactured by Sanyo Kasei Co., Ltd.) were melt-blended, cooled, coarsely pulverized, and then finely pulverized with a jet mill (“Labojet” manufactured by Nippon Pneumatic Mfg. Co., Ltd.), A toner powder having an average particle size of 8 to 12 μm was obtained and classified by a classifier (“MDS-2” manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to prepare a toner powder having an average particle size of 10 μm. To 300 g of this toner powder, 0.9 g of hydrophobic silica powder finely pulverized with a coffee mill was added and blended using a rotary table and a shaker to prepare a toner.

Example 2 β-hydroxyethyl was prepared in the same manner as in Example 1 except that 35 g of benzoyl peroxide was used as a polymerization initiator.
Meta acrylate is obtained a resin composition for toner which is copolymerized randomly, to prepare a toner in the same manner as in Example 1 from this toner resin composition.

Example 3 A resin composition for toner in which chloromethylstyrene was block-copolymerized in the same manner as in Example 1 except that 60 g of chloromethylstyrene was used as the monomer having a polar group. From the resin composition for toner, a toner was prepared in the same manner as in Example 1.

[0040]

Example 4 The same as Example 1 except that 120 g of β-hydroxyethyl methacrylate was used as the polar group-containing monomer and 360 g of styrene was used as the other monomer. A resin composition for toner was obtained in the same manner as described above, and a toner was prepared from this resin composition for toner in the same manner as in Example 1.

(Example 5 ) 120 g of behenyl alcohol as a low melting point crystalline compound
A toner resin composition was obtained in the same manner as in Example 1 except that the above was used.
A toner was prepared in the same manner as in.

Example 6 A toner resin composition was obtained in the same manner as in Example 1 except that 30 g of Perhexa MC was used as a polymerization initiator.
A toner was produced from this resin composition for toner in the same manner as in Example 1.

Example 7 120 g of St-BA-MMA copolymer having Mw of 2,000,000
A toner resin composition was obtained in the same manner as in Example 1 except that the above was used, and a toner was produced from this toner resin composition in the same manner as in Example 1.

Example 8 A toner resin composition was obtained in the same manner as in Example 1 except that 60 g of a high molecular weight alcohol having an Mw of 500 was used as the low melting point crystalline compound. A toner was prepared in the same manner as in Example 1.

Example 9 A toner resin composition was obtained in the same manner as in Example 1 except that 120 g of a high molecular weight alcohol having an Mw of 500 was used as the low melting point crystalline compound. A toner was prepared in the same manner as in Example 1.

Example 10 A toner resin composition was obtained in the same manner as in Example 1 except that 60 g of polyester having Mw of 3,500 was used as the low melting point crystalline compound. A toner was prepared in the same manner as in Example 1.

Comparative Example 1 A toner resin composition was obtained in the same manner as in Example 1 except that the low-melting-point crystalline compound behenyl alcohol was not added at all. A toner was prepared in the same manner as in 1.

(Comparative Example 2) A toner resin composition was obtained in the same manner as in Example 1 except that 400 g of behenyl alcohol was used as the low melting point crystalline compound, and this toner resin composition was obtained in the same manner as in Example 1. To prepare a toner.

(Comparative Example 3) Styrene 36 was used as a monomer.
A resin composition for toner was obtained in the same manner as in Example 1 except that 0 g, 50 g of n-butyl acrylate and 70 g of methyl methacrylate were used, and a toner was prepared from this resin composition for toner in the same manner as in Example 1. did.

Comparative Example 4 A resin composition for a toner was obtained in the same manner as in Example 1 except that 400 g of β-hydroxyethyl methacrylate was used as the polar group-containing monomer. A toner was prepared from the resin composition for toner in the same manner as in Example 1.

Comparative Example 5 A resin composition for toner was obtained in the same manner as in Example 1 except that 50 g of Perhexa MC was used as a polymerization initiator, and this resin composition for toner was obtained in the same manner as in Example 1. A toner was prepared.

(Comparative Example 6) A resin composition for toner was obtained in the same manner as in Example 1 except that 20 g of perhexa MC was used as a polymerization initiator, and the resin composition for toner was obtained in the same manner as in Example 1. A toner was prepared.

Comparative Example 7 St-BA-MM with Mw 90,000
A resin composition for toner was obtained in the same manner as in Example 1 except that 120 g of the A copolymer was used, and a toner was prepared from this resin composition for toner in the same manner as in Example 1.

The resin compositions for toner obtained in the above Examples and Comparative Examples and the toners using the same were evaluated for the following items, and the evaluation results are shown in Tables 1 to 3.

(1) Molecular Weight Measurement From the molecular weight distribution of the resin composition for toner obtained by gel permeation chromatography (GPC), the weight average molecular weight of the low molecular weight polymer component and the high molecular weight polymer component was determined. . Here, the GPC is "HTR-C" manufactured by Japan Millipore Limited, and "KF-800P" (one) manufactured by Showa Denko KK and "KF-" is used as a column.
"806M" (two) and "KF-802.5" (one) were connected in series and used. The measurement conditions were a temperature of 40 ° C., a sample concentration of 0.2 wt% THF solution (passed through a 0.45 μm filter), and an injection amount of 100 μl was injected. Standard polystyrene was used as a calibration sample.

(2) Measurement of glass transition point (Tg) Using a "DSC220C" manufactured by Seiko Denshi Kogyo Co., Ltd., a DSC curve of the resin composition for toner was measured under the measurement conditions of a heating rate of 10 ° C / min. The glass transition temperature (Tg) was obtained.

(3) Measurement of Shear Fracture Energy The resin composition for toner and the low melting point crystalline compound were measured. First, a 1 cm × 5 cm rectangular sample is prepared using an 80 mesh stainless steel mesh. Then, as shown in FIG. 1, the two samples A,
The tip portion of B was sufficiently impregnated with 0.2 g of the resin composition for toner (or low melting point crystalline compound) C that was heated and melted, and the overlap margin of the tip portions of Samples A and B was 1 cm.
A test piece D was produced by laminating the pieces so that the size was about 1 cm.

The test piece was subjected to a tensile shear strength test using a universal tensile tester ("Tensilon UTA-500" manufactured by Orientec Co., Ltd.) to measure breaking energy.
The value obtained by dividing this breaking energy by the adhesion area was taken as the shear breaking energy per unit area. The test conditions are
The distance between chucks was 30 mm, the pulling speed was 10 mm / min, and the temperature was 23 ° C.

(4) Preservation test 5 g of the toner was placed in a 100 ml sample bottle and kept at 45 ° C.
After standing in a constant temperature bath at 50 ° C. and 55 ° C. for 8 hours in sequence, the state of caking was visually observed to determine the temperature at which aggregation occurred. In the table,> 55 indicates that aggregation did not occur at 55 ° C.

(5) Measurement of fixing temperature 6.5 parts by weight of toner is mixed with 93.5 parts by weight of iron powder carrier having a particle size of about 50 to 80 μm to prepare a developer, and a copy image is formed using this developer. Obtained. The electrophotographic copying machine used is a modification of "Xerox 3500" manufactured by Fuji Xerox. The fixing temperature is such that the copy image obtained by changing the set temperature of the heat roller of the electrophotographic copying machine is rubbed with a pad, and the change rate of the density of the copy image, that is, the fixing rate is 8%.
The set temperature was 5%.

(6) Measurement of fixing strength: 30 above the fixing temperature obtained by the measurement in (5) above.
Sekisui Chemical Co., Ltd.'s "Sekisui Mending Tape" was attached to the copy image obtained at a high temperature of ℃, and then peeled off.
If there is no reduction in the density of the copied image, ◎ 10
Those with less than 10% were evaluated as ◯, and those with 10% or more were evaluated as x.

(7) Measurement of non-offset width The temperature range in which the offset did not occur was measured by variously changing the set temperature of the heat roller of the electrophotographic copying machine. In the table,>
200 indicates that the offset did not occur up to 200 ° C., and the temperature exceeding it could not be measured due to the convenience of the measuring device.

[0064]

[Table 1]

[0065]

[Table 2]

[0066]

[Table 3]

[0067]

EFFECTS OF THE INVENTION The resin composition for a toner of the present invention, having the above-mentioned constitution, provides a toner excellent in offset resistance, low temperature fixing property, storage stability and pulverizability, and also excellent in fixing strength. .

[Brief description of drawings]

FIG. 1 is a schematic view showing a test piece used for a tensile shear strength test.

[Explanation of symbols]

A, B sample (stainless steel mesh) C Toner resin composition (or low melting point crystalline compound) D test piece

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-194872 (JP, A) JP-A-8-44109 (JP, A) JP-A-8-95289 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. A vinyl-based copolymer having a styrene-based monomer and a (meth) acrylic acid ester-based monomer as constituent units, and a low melting point crystalline compound having —OH as a polar group at a terminal. A resin composition for a toner having a main component, wherein the vinyl-based copolymer has a weight average molecular weight (Mw) of 3,000 to 5
10,000 low molecular weight polymer components and weight average molecular weight (Mw) 10
1 to 5 million high molecular weight polymer components, and
In the vinyl-based copolymer , --OH or halogen is used as a polar group.
1 to 30% by weight of a component having an amine group, and the resin composition for a toner contains 1 to 30% by weight of a low-melting-point crystalline compound having -OH as a polar group at a terminal, and a unit. Shear fracture energy per area is 100-
A resin composition for toner, which is 2,000 N / m. 2. The toner resin composition according to claim 1, wherein the low melting point crystalline compound has a shear fracture energy per unit area of 100 to 5,000 N / m. . 3. A toner comprising the resin composition for toner according to claim 1 or 2.