JPH07113786B2 - Toner - Google Patents

Description

The present invention relates to a toner for developing an electrostatic charge image in electrophotography, electrostatic recording, electrostatic printing and the like.

[Conventional technology and its problems]

The electrophotographic method generally uses a photoconductive substance, forms an electrical latent image on a photoconductor by various means, and subsequently develops the latent image with a toner to fix a sheet such as paper. After the toner image is transferred onto it, it is fixed by heating, pressurizing, solvent vapor or the like to obtain a subject. Various methods and devices have been developed for fixing the above-mentioned toner image onto a fixing sheet such as paper, but the most general method at present is a heating and pressure bonding method using a heat roller.
In the method of fixing with a heat roller, since fixing is carried out under heat and pressure, it is fast and the thermal efficiency is very good, and therefore the fixing efficiency is good.

However, in the above method, since the surface of the heat roller and the toner image are in contact with each other under pressure in a molten state, a part of the toner image adheres to and transfers to the surface of the fixing roller, and this re-transfers to the next sheet to be fixed, so-called. An offset phenomenon may occur and the sheet to be fixed may be soiled. Therefore, preventing the toner from adhering to the surface of the heat fixing roller is one of the essential conditions of the heat roller fixing method.

By the way, the above-mentioned offset phenomenon easily occurs when a low molecular weight polymer is used. Therefore, the use of a crosslinked polymer is widely used as a method for preventing the offset phenomenon.

However, as a result of studies by the present inventors, when the degree of cross-linking is increased, the offset resistance is improved, but on the contrary, the fixing temperature is increased, and a binder for a toner having a good fixing-offset balance cannot always be obtained. . Therefore, in the conventional technique, the degree of cross-linking is suppressed to a low range to maintain a relatively good fixing-offset balance.However, even in this method, the temperature range in which the fixing-offset balances is extremely high. It is required to develop a toner that is well balanced over a narrow and wide range.

An object of the present invention is to obtain a toner having improved offset resistance, a wide fixing temperature range, and excellent fixability particularly at low temperatures.

[Means for solving problems]

In order to achieve these objects, the present invention provides a high molecular weight vinyl polymer obtained by reacting a vinyl polymer having an acid value with a metal compound, and a low molecular weight copolymer not involved in the reaction in a toner. The present invention has been completed by finding that the fact that it is contained in is effective.

That is, the present invention has an acid value of 3 to 50 and a weight average molecular weight of 7
A polymer obtained by reacting a vinyl-based polymer (A) of × 10 ³ or more with a metal compound, an acid value of 1 or less, and a weight-average molecular weight of 1 × 10 5.
^The present invention provides a toner characterized by containing ³ to 1 × 10 ⁵ vinyl polymer (B).

The vinyl-based polymer (A) of the present invention means vinyl-based monomer 1
It is a copolymer obtained by copolymerizing one or more species with unsaturated acids.
Here, vinyl-based monomers include, for example, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, cyclohexyl acrylate, lauryl acrylate, stearyl acrylate, benzyl acrylate, furfuryl acrylate. Acrylic acid esters such as tetrahydrofurfuryl acrylate, hydroxyethyl acrylate, hydroxybutyl acrylate, methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, butyl methacrylate, octyl methacrylate, lauryl methacrylate, stearyl methacrylate, cyclohexyl methacrylate,
Benzyl methacrylate, furfuryl methacrylate,
Methacrylic acid esters such as tetrahydrofurfuryl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl methacrylate, vinyltoluene, α-methylstyrene,
Aromatic vinyl monomers such as chlorostyrene, dibutyl maleate, dioctyl maleate, dibutyl fumarate,
Examples include unsaturated dibasic acid dialkyl esters such as dioctyl fumarate, vinyl esters such as vinyl acetate and vinyl propionate, and nitrogen-containing vinyl monomers such as acrylonitrile and methacrylonitrile.

The unsaturated acids include, for example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, cinnamic acid, maleic acid,
Unsaturated dicarboxylic acids such as maleic anhydride, fumaric acid, itaconic acid, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monooctyl fumarate, etc. And unsaturated dicarboxylic acid monoesters.

The vinyl-based polymer (A) of the present invention can be prepared by a known method in such a proportion that the acid value of the copolymer obtained from one or more of the above vinyl-based monomers and one or more of the unsaturated acids can be 3 to 50. It can be obtained by polymerization.

The acid value of the vinyl polymer (A) is from 3 to 50, and when the acid value is less than 3, the offset generation temperature does not increase, and when it exceeds 50, the lower limit fixing temperature increases. Further, the weight average molecular weight needs to be 7 × 10 ³ or more, and if it is less than 7 × 10 ³ , the offset generation temperature is low. The acid value is measured according to JIS K-5400.

The metal compound is a compound capable of reacting with an acid in a copolymer such as a metal oxide, a metal hydroxide, a metal halide, and an organometallic compound, and includes a metal ion having a valence of 2 or more. Things can be used. Suitable divalent metal ions
Ba ²⁺ , Mg ²⁺ , Ca ²⁺ , Be ²⁺ , Hg ²⁺ , Sr ²⁺ , Pb ²⁺ , Fe ²⁺ , Co
²⁺ , Ni ²⁺ , Zn ^2+, etc. Suitable trivalent metal ions include Al ³⁺ , Se ³⁺ , Fe ³⁺ , Co ³⁺ , Ni ³⁺ , Cr ³⁺ . Among the above-mentioned metal compounds, those having a higher reactivity give better results.

The reaction between the polymer (A) and the metal compound includes a method of reacting by kneading the above-mentioned polymer with the metal compound, a method of adding the metal compound to the polymerization system and reacting. The ratio of the vinyl polymer (A) to the metal compound is 5 to 200 equivalent%, preferably 5 to 100 equivalent% based on the acid value of the vinyl polymer (A).

The vinyl polymer (B) is a polymer obtained by polymerizing one kind or two or more kinds of vinyl monomers. Here, as the vinyl-based monomer, the vinyl-based monomer used in the vinyl-based polymer (A) can be exemplified here.

The acid value of the vinyl polymer (B) is required to be 1 or less, and when it exceeds 1, the lower limit fixing temperature becomes high. The weight average molecular weight is in the range of 1 × 10 ³ to 1 × 10 ⁵ . If it is less than 1 × 10 ³ , the strength of the toner is weak and the toner is excessively pulverized in the machine and the scattering is severe. If it exceeds 1 × 10 ⁵ , the lower limit fixing temperature becomes high.

The weight ratio of the polymer (A) reacted with the metal compound to the polymer (B) in the present invention is not particularly limited, but the effect of the present invention is to maintain the fixing temperature and dramatically increase the offset generation temperature. In order to obtain a toner having good improvement and pulverizability, the weight ratio of the polymer (A) reacted with the metal compound to the polymer (B) is preferably 10:90 to 90:10, and particularly 30: 70
~ 70: 30 is preferred.

In the present invention, by reacting the polymer (A) with a metal compound, that is, by crosslinking the polymer, the cohesive force is remarkably improved, the offset generation temperature is increased, and the polymer (B) not involved in the reaction is simultaneously contained. It is possible to maintain the fixing temperature and prevent deterioration of pulverizability. Therefore, when the acid value of the polymer (A) is 3 to 50 and the acid value of the polymer (B) is 1 or less, the fixability and the offset property are remarkably improved.

Further, the toner of the present invention is not inferior to conventional toners in toner properties such as blocking resistance, developing property, transfer property, cleaning property, crushing property, and charging property.

The method for producing the toner of the present invention includes, for example, a pulverized product of the polymer (A) or a reaction product of the polymer (A) and a metal compound, a pulverized product of the polymer (B), and a polymer (A). When a pulverized product of a reaction product with a metal compound is not used, a metal compound, various colorants typified by carbon black and a charge for adjusting triboelectrification property as needed, for example, nigrosine, charge of metal-containing azo dye, etc. Examples include a method in which a regulator and a low-molecular weight wax for preventing offset are kneaded with a kneader or the like, and then ground and classified. It is also possible to mix other resin components as long as the effect of the present invention is not impaired.
Other resin components include polyester resin, polyurethane resin, epoxy resin, styrene-butadiene resin, rubber and the like.

〔Example〕

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. still,
[Parts] represents parts by weight.

In the production examples, the reaction with the metal compound was confirmed by the change in MI (melt index) value. The MI value was measured with the following equipment and measurement conditions.

Equipment Toyo Seiki Seisakusho Co., Ltd. Melt indexer Measurement conditions Temperature 150 ℃ Load 2160g Temperature 190 ℃ Load 1000g Measurement method Measure the extrusion rate per 10 minutes by the manual cutting method.

Production Example 1 Monomers of the following composition were bulk-polymerized, then solution-polymerized in the presence of a xylol solvent, and desolvated to obtain a polymer having an MI value shown in Table 1. The molecular weight of this polymer is 2 ×
It was about 10 ⁵ .

Further, the polymer and 0.5 parts by weight of acetylacetone Ca are heat-kneaded to obtain the desired resins (A-1) to (A-4) and (a).
-1) to (a-3) were obtained.

Production Example 2 Solution-polymerization of the compositional monomers shown in Table 2 using an initiator AIBN (azoisobisisobutylnitrile) in the presence of a xylol solvent and desolvation were carried out to obtain a polymer (B-1 having a MI value shown in Table 2). ) (B-1) and (b-2) were obtained. The molecular weight of this polymer was about 5 × 10 ³ .

Example 1 Polymers (a-1) to (a-3), (A-1) to (A-
50 parts by weight of one of 4) and 50 parts by weight of (B-1),
5 parts by weight of carbon black, 1 part by weight of Spiron Black TRH, and 2 parts by weight of polypropylene wax are mixed, melt-kneaded by a twin-screw extruder, pulverized by a jet pulverizer, and classified to obtain a toner having a particle diameter of about 10 μ. Obtained.

This toner was evaluated using a copying machine. Table 3 shows the evaluation results
Shown in.

When the acid value of the polymer (A) is less than 3, the lower limit fixing temperature is not changed, but the offset generation temperature is not so high. If the acid value is more than 50, the offset generation temperature becomes sufficiently high, but on the contrary, the lower limit fixing temperature becomes high, which is not desirable. Therefore, the acid value of the polymer (A) is 3 to 50.
Is desirable.

Example 2 50 parts by weight of polymer (A-2) and (B-1) (b-1) (b
A toner was manufactured in the same manner as in Example 1 except that 50 parts by weight of the one type of polymer of -2) and other conditions were used.

Evaluation was performed in the same manner as in Example 1, and the results are shown in Table 4.

From Table 4, when the acid value of the polymer (B) is more than 1, the lower limit fixing temperature becomes high, which is not desirable in the physical properties of the toner. Therefore, the acid value of the polymer (B) is preferably 1 or less.

Production Example 3 Resins having the same composition as in (A-2) of Production Example 1 but different molecular weights were synthesized. It is shown in Table 5. This resin was polymerized and desolvated in the same manner as in Production Example 1, and then acetylacetone Ca was heat kneaded to obtain the objective resins (a-4), (A-5) to (A-).
8) was obtained.

Example 3 Polymers (a-4), (A-2), (A-5) to (A-
50 parts by weight of 8), (B-1) 50 parts by weight, carbon black 5 parts by weight, Spiron Black TRH 1 part by weight,
Two parts by weight of polypropylene wax were mixed, melt-kneaded with a twin-screw extruder, and then pulverized with a jet pulverizer for classification to obtain a toner having a particle diameter of about 10 μm. This toner was evaluated using a copying machine. The evaluation results are shown in Table 6.

As can be seen from Table 6, when the weight average molecular weight of the polymer (A) is 5 × 10 ⁻³ , the effect of increasing the offset generation temperature is small. Therefore, it is desirable that the weight average molecular weight of the polymer (A) is 7 × 10 ⁻³ or more.

Production Example 4 Resins having the same composition as (B-1) in (Production Example 2) but different molecular weights were synthesized and desolvated to obtain a polymer having an MI value shown in Table 7.

Example 4 50 parts by weight of polymer (A-2), polymer (b-3), (b-
4), 50 parts by weight of one of (B-1) to (B-4),
5 parts by weight of carbon black, 1 part by weight of Spiron Black TRH, and 2 parts by weight of polypropylene wax are mixed, melt-kneaded by a twin-screw extruder, pulverized by a jet pulverizer, and classified to obtain a toner having a particle diameter of about 10 μ. Obtained. This toner was evaluated using a copying machine. The evaluation results are shown in Table 8.

From Table 8, when the weight average molecular weight of the polymer (B) is 5 × 10 ^-2 , the fixing-offset balance is appropriate, but the strength of the toner is weak because the molecular weight of the polymer (B) is small. The toner is excessively pulverized in the machine, and the toner scattering is seriously undesirable.

Further, when it is 5 × 10 ⁵ , the lower limit fixing temperature becomes high, which is not desirable in terms of toner physical properties.

Therefore, the weight average molecular weight of the polymer (B) is 1 × 10 ³ to
It is desirable that it is 1 × 10 ⁵ .

Example 5 5 parts by weight of carbon black and Spyron black were used by changing the blend ratio of the polymer (A-2) and the polymer (B-1).
1 part by weight of TRH and 2 parts by weight of polypropylene wax were mixed, melted and kneaded by a twin-screw extruder, then pulverized by a jet pulverizer, and classified to obtain a toner having a particle diameter of about 10 μm.

This toner was evaluated using a copying machine. Table 9 shows the evaluation results.
Shown in.

From Table 9, when (A) / (B) is 5/95, the effect of increasing the offset generation temperature is small, and scattering is not desirable. In the case of 95/5, the lower limit fixing temperature rises, which is not desirable. Therefore, the ratio is preferably 10/90 to 90/10
30/70 to 70/30 is preferable.

Example 6 In order to examine the influence of the kind and amount of the metal compound, 50 parts by weight of a resin obtained by heat-kneading the base resin of the polymer (A-2) with the metal compound shown in Table 10 below and the polymer (B -1)
50 parts by weight, carbon black 5 parts by weight, spirone black TRH 1 part by weight, polypropylene wax 2 parts by weight are mixed, melt-kneaded with a twin-screw extruder, pulverized with a jet pulverizer, and classified to carry out particle size. About 10μ of toner was obtained.

This toner was evaluated using a copying machine. Table 10 shows the evaluation results.
Shown in.

From Table 10, it was found that a toner having a good fixing-offset balance can be obtained regardless of the kind and amount of the metal compound.

[Advantages of the Invention] As described above, by using the toner containing the polymer of the present invention, it is possible to obtain a toner having a much better fixing-offset balance than the conventional crosslinking type toner.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP-A-57-178249 (JP, A) JP-A-61-126562 (JP, A) JP-A-62-9356 (JP, A) JP-A-61- 123857 (JP, A) JP 61-110155 (JP, A) JP 61-110156 (JP, A) JP 56-158340 (JP, A)

Claims (1)

[Claims] 1. A vinyl polymer (A) having an acid value of 3 to 50 and a weight average molecular weight of 7 × 10 ³ or more reacted with a metal compound, and an acid value of 1 or less and a weight average molecular weight of 1 × 10 5. ³ ~ 1 x 1
Toner for electrophotography which is characterized by containing 0 ⁵ vinyl polymer of (B).