JPH0776848B2 - Static charge imparting agent - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electrostatic charge-imparting agent.

[Conventional technology]

Conventionally, in electrophotography, electrostatic recording paper, etc., an electrostatic charge imparting agent that is negatively or positively charged is used as an internal or external additive to the toner for the purpose of imparting electrostatic charge to the toner used for developing an electrostatic charge image. It is known that means are used.

As the positively-charged electrostatic charge imparting agent, a polymer type acrylic resin having a quaternary ammonium salt group described in U.S. Pat. No. 4,415,646 and a polystyrene resin described in JP-B-64-44308 are known. There is.

[Problems to be solved by the invention]

However, the conventionally known polymer-based electrostatic charge imparting agent has an external addition method of the toner, and does not substantially have an internal addition method. Poor dispersibility in the toner resin, which is the main constituent of the toner, causes uneven charging of the toner particles, resulting in poor image quality, and insufficient thermal stability that causes partial decomposition at the toner processing temperature conditions. In addition, there is a problem that a stable image has a particularly large environmental dependency and is stable, and it is difficult to maintain a stable charge for long-term use even if a constant static charge is maintained in the initial stage of copying.

[Means for solving problems]

The inventors of the present invention have conducted earnest studies for the purpose of obtaining an electrostatic charge imparting agent that is uniformly dispersed in a toner resin, has a uniform charge, maintains a stable charge for long-term use, and has less environmental dependence. As a result, the present invention has been reached.

That is, the present invention is an amino group-containing resin having a structure obtained by the reaction of a resin selected from the group consisting of a copolymer resin of olefin and an unsaturated carboxylic acid and an unsaturated dibasic acid-modified polyolefin resin, or An electrostatic charge imparting agent comprising a resin having a group having a structure in which an amino group is further converted into an amine salt form or a quaternary ammonium salt form.

In the unsaturated dibasic acid-modified polyolefin resin of the present invention, examples of the unsaturated dibasic acid include unsaturated dicarboxylic acids such as maleic acid, itaconic acid and their acid anhydrides. Maleic acid and maleic anhydride are preferred.

Examples of the polyolefin resin include polymers and copolymers of monoenes and / or polyenes having 2 to 12 carbon atoms, such as polypropylene, polyethylene, random or block copolymers of propylene and ethylene, and propylene and at most 12 carbon atoms. Random or block copolymers with other α-olefins (1-butene, etc.), terpolymers of propylene-ethylene-diene monomers (butadiene, etc.), chlorinated polypropylene, chlorinated polyethylene and polybutadiene, and these two Mixtures of more than one species are mentioned. Preferred are polypropylene, a random or block copolymer of propylene and ethylene, and a random or block copolymer of propylene and other α-olefins having at most 12 carbon atoms, and more preferred is polypropylene.

The weight average molecular weight of this polyolefin resin is usually 24
From 1 to 1 million, preferably from 4000 to 500,000. If the weight average molecular weight exceeds 1,000,000, it is disadvantageous in that the appropriate dispersibility in the toner resin is maintained.

Low molecular weight polyolefin resins with a molecular weight of around 4,000 are high molecular weight polyolefin resins (weight average molecular weight from 100,000).
It may be a low molecular weight resin produced as a by-product during the production, or a polyolefin resin obtained by thermal degradation of a high molecular weight polyolefin resin. Oxidized polyolefin (acid value is usually 5 to 20) or non-oxidized polyolefin resin may be used.

The amount of unsaturated dibasic acid units (which become saturated dibasic acid units after modification) in the unsaturated dibasic acid-modified polyolefin resin in the present invention is usually 1 to 20% based on the weight of the resin,
It is preferably 4 to 15%. If it is less than 1%, the charge imparting effect is difficult to be obtained, and if it exceeds 20%, the modification with unsaturated dibasic acid is difficult to proceed.

In obtaining the modified polyolefin resin, the ratio of the polyolefin resin to the unsaturated dibasic acid is usually 1 to 10 moles of the unsaturated dibasic acid which can react with the unsaturated dibasic acid in the polyolefin resin. Ratio up to moles.
Increasing the amount of unsaturated dibasic acid to more than 1 mol does not significantly affect the degree of modification.

In the present invention, olefin (having 2 to 8 carbon atoms, such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-octene, 2-butene) and unsaturated carboxylic acid (acryl) are used. It is also possible to use a copolymer with an acid, methacrylic acid, itaconic acid, maleic acid, dodecenyl maleic anhydride, etc. and optionally a vinyl ester (vinyl acetate, vinyl propionate etc.).
In this case, the amount of unsaturated carboxylic acid is usually 4-20%, based on the weight of total monomers.

In the following description, the unsaturated dibasic acid-modified polyolefin resin will be described as a representative.

The unsaturated dibasic acid-modified polyolefin resin in the present invention is prepared by dissolving a polyolefin resin and an unsaturated dibasic acid in an organic solvent and reacting them under heating in the presence of an initiator such as an organic peroxide. Can be obtained. The organic peroxide may be one generally used as an initiator in radical polymerization, and examples thereof include dialkyl peroxide such as dicumyl peroxide and diaryl peroxide such as benzoyl peroxide.

Examples of the organic solvent include aliphatic hydrocarbons (hexane, heptane, etc.), aromatic hydrocarbons (benzene, toluene, xylene, etc.), halogenated hydrocarbons (chlorobenzene, etc.), and mixtures of two or more thereof.

The reaction temperature may be a temperature at which the polyolefin used is dissolved, and generally 60 ° C to 160 ° C is preferable. It can also be obtained by reacting by a melting method without using a solvent.

The acid value (including acid anhydride) of the obtained modified polyolefin resin is usually 10 to 300, preferably 40 to 200.

As the amine in the present invention, a monoamine having a primary, secondary or tertiary amino group having an active hydrogen capable of reacting with a group having an acid or acid anhydride structure of an unsaturated dibasic acid-modified polyolefin resin, or Examples include polyamines.

Such amines include aliphatic monoamines (hydroxyalkylamines such as hydroxyethyldimethylamine, hydroxyethyldilaurylamine, hydroxyethylpropylamine, dihydroxyethyloleylamine and trihydroxyethylamine), alicyclic and heterocyclic monoamines. , (N-hydroxyethylcarbazole, N-hydroxyethylcyclohexylamine, N-hydroxyethylmorpholine, benzoxazole, etc.) Aliphatic polyamines (ethylenediamine, N, N-dimethyl-1,3-propanediamine, N, N- Diethyl-1,6-
Hexanediamine, N, N-diphenylethylenediamine,
N, N-dihydroxyethyl-1,3-propanediamine, tetramethylenepentamine, etc.) and alicyclic or heterocyclic polyamines (pyrazole, benzimidazole, N-
Hydroxyethylimidazole, N-hydroxyethylpurine, N, N'-dihydroxyethylpiperazine and N, N
-Dimethyl-1,4-phenylenediamine and the like can be mentioned.

Preferred among these amines are hydroxyethyldimethylamine, hydroxyethyldilaurylamine, N-hydroxyethylmorpholine, N, N-dimethyl-1,3-propanediamine, N, N-diphenylethylenediamine and N, N. -Dimethyl-1,4-phenylenediamine.

Further, in both monoamine and polyamine, one group having an active hydrogen such as a primary or secondary amino group is preferable in one molecule. If it has 2 or more, a complicated crosslinking reaction occurs with the dibasic acid-modified polyolefin and the dispersibility in the toner resin is significantly lowered.

In obtaining the amino group-containing resin, the ratio of unsaturated dibasic acid-modified polyolefin resin to amine is usually up to 2 mol of amine per 1 mol of carboxyl group in the modified resin. It is preferably about 1: 1. If the amine is used in excess, it is necessary to remove the unreacted amine. If the unreacted amine remains, it migrates in the toner and a constant static charge cannot be obtained. Reaction temperature is usually 60 ℃
To 130 ° C. If the temperature is higher than 130 ° C, the reaction product is decomposed and the coloring becomes remarkable.

The reaction time is usually 3 to 20 hours. The reaction is usually carried out in a solvent, but the reaction is possible without using a solvent.

Examples of the solvent include alcohols (methanol, ethanol, etc.), aromatic hydrocarbons (toluene, xylene, etc.), amides (dimethylformamide, etc.), and mixed solvents of two or more thereof.

Solid content concentration is 5% to 70% by weight, preferably 20%
From 60%.

The amino group-containing resin having the obtained structure includes a salt, an amide, an imide and / or an ester (in the case of a hydroxyl group-containing amine) of a modified polyolefin resin with a dicarboxylic acid (or its acid anhydride) moiety and an amine. For example, the expression Or expression When the amine represented by the formula (1) is used, at least a part of the carboxyl group (or acid anhydride group) of the modified polyolefin resin is replaced with one or two or more groups represented by the following formula. .

In the formula, at least one of R ₁ , R ₂ and R ₃ is a hydrocarbon group which may have a nitrogen atom (preferably a tertiary amino group) and / or an oxygen atom (hydroxyl group, ether oxygen, etc.) (for example, R ₄ , -A'-OH, And the rest may be H. _{Two of} R ₁ , R ₂ and R ₃ (or 3
May be combined with each other to form a heterocycle with N. A,
A ', A "is a divalent hydrocarbon group (e.g. an alkylene radical of _{C 2 ~ 4), R 4} , R 5 is a monovalent hydrocarbon group (e.g., C ₁ ~ ₁₈
Alkyl, alkenyl, aryl groups, etc.) and R ₅
May be H.

Examples of the amine salt in the present invention include a neutral salt of an organic acid or an inorganic acid and an amino group. Examples of the organic acid include monobasic acids such as acetic acid and lauric acid, dibasic acids such as maleic acid and fumaric acid, and tribasic or higher polybasic acids such as trimellitic acid.

Examples of the inorganic acid include boric acid. Strong acids such as sulfuric acid and hydrochloric acid may corrode the machine.

The amine salt in the present invention can be easily obtained by a usual neutralization reaction between an amine and an acid. In addition, an intramolecular neutralization salt of the carboxyl group and the amino group of the unsaturated dibasic acid-modified polyolefin resin which is ring-opened by the reaction can also be mentioned.

The amino group means an amino group having a structure obtained by an esterification reaction between an unsaturated dibasic acid-modified polyolefin resin and an amine having a hydroxy group, or a polyamine having a primary or secondary amine. The residual amino group that is not involved in amidation or imidation of the structure obtained by the reaction, and examples thereof include primary, secondary, and tertiary amino groups.

The tertiary amino group is practically useful.

Examples of the quaternary ammonium salt in the present invention include those in which at least a part of the carboxyl group (or acid anhydride group) of the modified polyolefin resin is substituted with one or more groups represented by the following formula. To be

(Where Q is And these amphoteric metal salts. A, R ₁ , R ₂ , R ₃ and A ′
Is the same as before.

Specific examples of Q (quaternary ammonium base) include, for example, trimethylammonium chloride group, tributylammonium bromide group, dimethylbenzylammonium iodide group, tribenzylammonium chloride group, N-methylmorpholinium methosulfate group, trimethyl. Ammonium dimethylphosphonate group, trimethylammonium p-toluenesulfonate group, trimethylammonium naphthylsulfonate group,
Trimethylammonium fluoroborate group, Can be mentioned.

Preferred are tribenzylammonium chloride group, dimethyllaurylammonium bromide group and tribenzylammonium dimethylphosphonate group.

The quaternary ammonium salt in the present invention is, for example, a residual tertiary amino acid that is not involved in amidation or imidation of an amino group-containing resin having a structure obtained by reacting an unsaturated dibasic acid-modified polyolefin resin with an amine. It can be obtained by reaction of a group with a quaternizing agent.

Examples of the quaternizing agent (including amphoteric agent) include alkyl halides or substituted alkyl halides (methyl chloride, butyl bromide, benzyl chloride, etc.),
Dialkyl sulfuric acid (dimethyl sulfuric acid, diethyl sulfuric acid, etc.),
Tolualkylphosphonates (such as trimethylphosphonate) and monohaloacetic acids (such as monochloroacetic acid),
Examples thereof include monohaloacetic acid salts (sodium monobromoacetate, etc.).

The tertiary amino group and the quaternizing agent are usually 1: 0.5 to 1: 1.1 mol. It is not preferable to use too much quaternizing agent. The reaction temperature, time, and solvent used are almost the same as the reaction conditions of the dibasic acid-modified polyolefin resin and amine. The reaction temperature is preferably slightly lower, up to 110 ° C.

Further, the quaternary ammonium salt is changed to a structure other than the counterion obtained by the reaction with the quaternizing agent by reacting the obtained negative counterion of the quaternary ammonium salt with, for example, a sulfonate. (Negative ion of p-toluenesulfonic acid, negative ion of hydroxynaphthylsulfonic acid, negative ion of tetrafluoroborate, etc.,
It is also possible to obtain a group amphoterized by a monohaloacetic acid salt, which has a structure neutralized by a metal ion).

Among these groups having a structure in the form of amine salt and quaternary ammonium salt, those having a structure containing a tertiary amino group and / or an organic acid salt of a tertiary amino group can withstand the temperature during toner kneading. It is preferable in terms of thermal stability and easy maintenance of an appropriate melt viscosity during processing.

A quaternary ammonium salt group is preferred from the viewpoint of charge imparting ability.

Either is selected according to the purpose of use.

Specific examples of the resin in the present invention include a. N, N Dimethylaminopropyl maleimidated polypropylene b. Benzyl chloride quaternary product of the above maleimidated polypropylene c. P-toluenesulfonic acid ion instead of the chlorine ion in (b) d. Polyamidated polypropylene with the tertiary amino group ampholyzed with monochloroacetic acid. (2: 8) Copolymer of N, N dimethylaminoethyl maleimidated ethylene and propylene f. Examples include morpholino ethyl ester of maleated polyethylene.

The amino group-containing resin of the present invention, or a resin having a group having a structure in which the amino group is further in the form of an amino salt or a quaternary ammonium salt, is a composition, structure, molecular weight, distribution of molecular weight, and molecular weight of a polyolefin resin. Various melt viscosities and softening points can be obtained depending on the degree of saturation dibasic acid modification and the type of polar groups such as amino groups that are derived. Generally, it is light brown and solid at room temperature.

When melted, the viscosity at 160 ° C is usually 100 centipoise or more. From a practical range, it is preferably 200 centipoise or more, but a low viscosity is preferable because dispersibility in the toner resin is easy. The upper limit is not particularly limited.

Many modified resins having a quaternary ammonium ion group exceed 100,000 centipoise.

Generally, the viscosity increases in the order of modified resin with unsaturated dibasic acid, amino group-containing resin, amine salt or quaternary ammonium salt.

The softening point is usually 100 to 250 ° C. or higher, and preferably 120 to 200 ° C. or higher from the viewpoint of toner resin.

The electrostatic charge-imparting agent of the present invention is usually used by mixing and melting a toner resin together with a colorant, a fluidizing agent, etc. in a toner manufacturing process according to a known method.

Examples of the toner resin generally include styrene (meth) acrylic acid ester copolymer resins, polyester resins, epoxy resins, and the like.

The amount used is usually 0.5 to 30 parts by weight per 100 parts of the toner resin. It is preferably 1 to 20 parts. Depending on the purpose and quality used, more can be used than conventional static charge imparting agents. This is advantageous in that the electrostatic charge can be uniformly charged to each toner particle.

Some colorants also have an effect as an electrostatic charge imparting agent, for example, carbon black, nigrosine dye, aniline blue, chrome yellow, deupon oil red, quinoline yellow, malachite green oxalate and other metals. Examples include dyes.

Examples of the fluidizing agent include silica derivatives, fatty acid metal salts, metal aluminum and the like.

The electrostatic charge-imparting agent of the present invention may be added in advance in a toner resin production process such as a polymerization process, and may be mixed in the toner resin or used in a partially bonded form.

Further, after being made into a toner, it can be mixed and used in a powder state.

〔Example〕

The present invention will be further described below with reference to examples, but the present invention is not limited thereto. The middle part of an Example shows a weight part.

Example 1. 886 parts of low molecular weight polypropylene (A) having a weight average molecular weight of 8500 and a melt viscosity of 160 ° C. and 0.7 poise and 114 parts of maleic anhydride were dissolved in 1500 parts of a xylene solvent by heating and dissolved, followed by catalysis. Then, 40 parts of dicumyl peroxide was added and the temperature was raised, and the reaction was carried out at the boiling point of the solvent for 4 hours to obtain a maleated polypropylene having an acid value of 115 in terms of solid content. The maleic anhydride content is 10.1%. Solvent distillation part of this thing
905 parts and 95 parts of N, N dimethyl-1,3-propanediamine were dissolved in 1810 parts of toluene and reacted at the boiling temperature of the solvent for 15 hours.

Water was added to the toluene solution of the reaction mixture and stirred, and the toluene-soluble resin component obtained by removing the water-soluble portion was analyzed,
The imide bond was confirmed by infrared spectrum.

After the solvent was distilled off, the total amine value of the electrostatic charge imparting agent of the present invention was 48.
To obtain N, N-dimethylaminopropylmaleimidated polypropylene. The appearance was light brown solid, and the softening point was 143 ℃.

Effect of application of electrostatic charge-Preparation of sample-100 parts of styrene-acrylic acid butyl ester copolymer resin (80 parts of styrene, 20 parts of butyl acrylate, weight average molecular weight 110,000) and 100 parts of the present invention obtained in this example. 3 parts, 5 parts and 7 parts of the electrostatic charge imparting agent were premixed in a sample mill. Sample names are I-3, I-5 and I-
7

-The premixed sample was kneaded for 30 minutes at 138 ° C to 140 ° C using a Labo Plastomill (manufactured by Toyo Seiki).

Then, after preliminary pulverization, fine pulverization was performed with a jet mill to obtain a pulverized product having an average particle size of 15 μm.

-As a comparative product, a sample to which the charge-imparting agent was not added in the same manner as above and a sample to which only 3 parts of the raw material polypropylene used for the maleated polypropylene were added were used. The sample names are I-0 and A-3, respectively.

-Measurement of electrification 0.5 parts of the sample prepared above and 25 parts of a carrier made of Nippon Iron Powder were sampled in a wide-mouthed bottle with a stopper, and the humidity was adjusted to 25 ° C and 65% RH. The mixture was mixed under the same conditions for 1 minute, 5 minutes, and 10 minutes with a shaker, and then the charge amount was measured at the same temperature and humidity using a blow-off charge amount measuring device (manufactured by Toshiba).

The measurement results are shown in Table 1.

The comparative products I-0 and A-3 of the resin alone were negatively charged, but the comparative examples I-3, I-5 and I-7 of the present invention were positively charged, and the friction time with the carrier was It was confirmed that the value remained almost constant after reaching the equilibrium charge regardless of the temperature.

Further, when the flow characteristics of the powders of Samples I-3 and A-3 were compared, I-3 was better.

Example 2. (2-1) 1000 parts of the imidized product of the maleated polypropylene obtained in Example 1 and 110 parts of benzyl chloride were dissolved in a toluene solvent and reacted at the boiling temperature of toluene for 5 hours.
The total amine value of the reaction product after the solvent was distilled off was 1.5, and it was confirmed that the static charge imparting agent (quaternary ammonium salt) of the present invention having a chlorion as a negative counterion was produced. The appearance of this product after solvent evaporation was light brown, solid, and the melt viscosity was 160 ° C, 100,000 centipoise or more.

The softening point was above 200 ° C.

(2-2) After dissolving 891 parts of maleimidated polypropylene having a quaternary ammonium salt in which the negative ion obtained in (2-1) is a chlorine ion in a solvent, 134 parts of sodium p-toluenesulfonate Add 20% aqueous solution of
After stirring for an hour, chloro ion was replaced with sulfonate ion. After removing the salt produced by the reaction and removing the solvent, a maleimidated polypropylene, which is an electrostatic charge imparting agent of the present invention, having a quaternary ammonium salt having a sulfonate ion as a negative counter ion was obtained.

The product had a light brown solid appearance and a softening point of 200 ° C or higher.

(2-3) 953 parts of the maleimidized polypropylene obtained in Example 1 and 95 parts of sodium monochloroacetate were dissolved in a toluene solvent and reacted at 90 ° C. for 8 hours with stirring. After removing the by-produced salt and distilling off the solvent, an electrostatic charge imparting agent of the present invention having a total amine value of 3 and an amphoteric tertiary amine group was obtained. The appearance of this product was a light brown solid.

Evaluation of electrostatic charge Styrene / acrylic acid ester copolymer resin (softening point 145
(C; ring and ball method, Tg.58 ° C.) 6 parts of each of the electrostatic charge imparting agents (2-1), (2-2) and (2-3) of the present invention in 100 parts.
A part was added and a measurement sample was prepared in the same manner as in Example 1. The sample names are II-6, III-6 and IV-6.

Separately, 10 parts of Carbon Black MA-100 (manufactured by Mitsubishi Kasei) and 6 parts of the electrostatic charge imparting agent (2-1) were added to the above copolymer resin to prepare a measurement sample with the same formulation.

The sample name is V-6.

Table 2 shows the results of measuring the amount of electrification by controlling the humidity of each of the four obtained samples to 20 ° C and 70% RH.

All samples showed positive charging.

Sample V-6 to which carbon was added had approximately 20 μC / g lower charge than Sample II-6 to which the same static charge imparting agent was used but no carbon was added. Change in charge with respect to friction time with carrier Was almost the same throughout the measurement.

Example 3. 440 parts of polypropylene having a weight average molecular weight of 54,000 and a melt viscosity of 160 ° C. and 40 poise and 35 parts of maleic anhydride were dissolved by heating in 700 parts of a toluene solvent, and then 21 parts of dicumyl peroxide as a catalyst. After the addition, the temperature was raised with stirring and the reaction was carried out at the boiling point of the solvent for 8 hours to obtain a maleated polypropylene having an acid value of 74.

944 parts of a solvent distillate of this product and 110 parts of dimethylethanolamine were dissolved in 1000 parts of toluene and reacted at the boiling point of the solvent for 15 hours.

After completion of the reaction, the resulting reaction product had a total amine value of 68 and an acid value of 3, and the acid anhydride type group of the maleated polypropylene was ring-opened and esterified by the reaction with the amine. confirmed. Then, half of the amine value was neutralized with HBr to obtain a total amine value of 34.

Charging characteristics Example 1 was prepared by mixing 100 parts of a styrene / methacrylic acid butyl ester copolymer resin having a weight average molecular weight of 160,000 with 2 parts, 4 parts, and 6 parts of the electrostatic charge imparting agent prepared in this example, respectively. A measurement sample was prepared by the same method. Name the samples VI-2, VI-4
And VI-6.

Separately, as a comparative product, 0.5 parts, 1 part, and 2 parts of benzyldimethyllauryl ammonium chloride as a low-molecular-weight quaternary ammonium salt were added to prepare similar measurement samples.
The sample names are VII-0.5, VII-1 and VII-2.

Separately, 1 part and 4 parts of a copolymer of vinylbenzyltrimethylammonium chloride and styrene (50:50) was similarly added as a polymeric quaternary ammonium salt to prepare measurement data. Sample names are VIII-1 and VIII-4
And

Table 3 shows the results of measuring the charge amount in the same manner as in Example 1 except that the humidity of the sample was adjusted to 25 ° C. and 50% RH.

As shown in No. 3, all the comparative products having quaternary ammonium ion groups show positive charge, but the low molecular weight sample VII system has a small charge amount, and the rising after friction start is slow and the equilibrium is reached. It is hard to get a value.

On the other hand, it was observed in the plastomill-kneaded sample that the polymer sample VIII system had a small amount of charge and had very poor dispersibility in the resin.

On the other hand, the electrostatic charge-imparting agent of the present invention is easily microdispersed in the resin (about 1 to 6 μm), and in an appropriate addition amount range, the equilibrium is almost maintained regardless of the friction time, and the charge at the start of friction is charged. It was confirmed that the rising edge of was quick. Also,
It was confirmed that the dependency on humidity was smaller in the imparting agent of the present invention than in the comparative product 2 series.

Example 4 Heat-degraded low molecular weight low density polyethylene having a melt viscosity of 290 centipoise at 140 ° C. was reacted with maleic anhydride in a xylene solvent to obtain a maleated polyethylene having an acid value of 30 in terms of solid content. .

Then, it was reacted with N-hydroxyethylmorpholine to obtain a morpholinoethyl esterified compound in which the group having an acid anhydride structure was ring-opened. The appearance is light brown,
It was solid.

The electrostatic charge imparting agent of the present invention in which the tertiary amino group was quaternized with trimethylphosphate was added to the formulation of Example 2 containing 10 parts of carbon to prepare a cohesive toner. It showed + 25μC / g at 20 ℃ and 40% RH.

Example 5 90 parts of ethylene and 10 of dimethylaminoethyl methacrylate
Parts were reacted under pressure in the presence of a benzoyl peroxide catalyst at 150 ° C. to 165 ° C. for 7 hours to obtain a copolymer resin having a weight average molecular weight of 25,000.

Six parts of this product were uniformly mixed with 100 parts of the styrene-acrylic acid ester copolymer resin of Example 2 and 10 parts of carbon black MA-100, and pulverized to prepare a cohesive toner, and the charging was evaluated. It showed +20 µC / g at ℃ and 60% RH.

〔The invention's effect〕

 The electrostatic charge imparting agent of the present invention has the following effects.

The electrostatic charge imparting agent of the present invention having a polar group having an electrostatic charge imparting function in a pendant type on a polyolefin resin skeleton is
In general, although other polymer-type imparting agents having polar groups have poor dispersibility in the toner resin, they are characterized by being uniformly dispersed in the micro state even though they are the same polymer type.

The conventionally known low-molecular weight charge-imparting agent having a molecular weight of several hundreds to 1,000 has a large proportion of the polar group in the molecular weight, and therefore has poor compatibility with the toner resin and is not uniformly dispersed in the resin. Further, for example, an electrostatic charge imparting agent known as a polyacrylic polymer has a poor compatibility, so that it can be applied to toner only by an external addition method. Poor dispersion causes non-uniform charging of toner particles and causes a reduction in image humidity.

Since the electrostatic charge-imparting agent of the present invention can be finely dispersed in about 1/10 or less of toner particles, it can be used even by a method of internally adding to the toner, and the toner particles are uniformly charged and are clear and good. Images can be obtained.

The electrostatic charge imparting agent of the present invention is uniformly micro-dispersed in the toner resin, but they are independent of each other, and unlike the low molecular weight type electrostatic charge imparting agent, migration with time in the toner, especially surface layer There is substantially no migration to the resin, and unlike some electrostatic charge imparting agents having too good compatibility, it does not continuously disperse in the resin so as to be electrically continuous with each other.

Therefore, the electric charge once charged due to friction does not easily leak from the toner particles, so that high electric charge can be maintained. That is, it has an excellent charge imparting ability. Further, it has a characteristic that it does not substantially change with time.

Since the electrostatic charge-imparting agent of the present invention can be used by being added to the toner resin, unlike a polymer type electrostatic charge-imparting agent by a certain toner surface treatment, the ratio of soiling the carrier during continuous copying is much less. It is possible to maintain stable image quality for a long period of time.

A method of introducing a polar group having an electrostatic charge imparting function such as a tertiary amino group into the toner resin skeleton is also known, but these are also used during resin production and during melt kneading for toner formation, The number of times that a high thermal history is passed is large, and in particular, when a resin is manufactured, it receives a longer thermal history than during toner processing, so that the effect tends to be reduced due to partial thermal decomposition of the polar group having the electrostatic charge imparting function. Is inevitable. Further, a polar group having a larger effect of imparting an electrostatic charge has a problem that the tendency is stronger, but since the imparting agent of the present invention is substantially limited to the heat history only at the time of melt kneading of the toner, it is possible to maintain a high imparting performance. it can.

Since the electrostatic charge imparting agent of the present invention can easily introduce various polar groups, it is easy to obtain a target level of charge adjusting ability.

The electrostatic charge-imparting agent of the present invention can be incorporated into a toner resin by appropriately selecting the molecular weight of the polyolefin resin as a polymer skeleton in a low molecular weight region (for example, a region having a weight average molecular weight of several thousands to tens of thousands). Not only can the degree of dispersion be changed, but it can also have a release effect from the heat roll during copying. Even when it is used in combination with a low molecular weight polyolefin, the compatibility with the electrostatic charge imparting agent of the present invention is good, so that the effect is evenly exhibited effectively.

The electrostatic charge imparting agent of the present invention is positively charged.
Conventionally, nigrosine dyes have been known as positively charged electrostatic charge imparting agents, but since they are dye-based, they are colored, and their use is restricted. However, the electrostatic charge imparting agent of the present invention can have a structure without coloring, and has a high positive electrostatic charge imparting ability.

These are excellent features that conventional electrostatic charge imparting agents do not have.

The electrostatic charge imparting agent of the present invention is useful for toners used for electrophotography, electrostatic recording paper, etc. because of the above effects.

Claims (3)

[Claims] 1. An amino group-containing resin having a structure obtained by reacting a resin with a resin selected from the group consisting of a copolymer resin of olefin and unsaturated carboxylic acid and an unsaturated dibasic acid-modified polyolefin resin, or An electrostatic charge imparting agent comprising a resin having a group having a structure in which the amino group is further in the form of an amine salt or a quaternary ammonium salt. 2. The imparting agent according to claim 1, wherein the copolymer resin and the polyolefin resin each have a propylene unit. 3. The imparting agent according to claim 1 or 2, wherein the amine is a polyamine having at least primary and / or secondary amino groups, or an amine having a hydroxyl group.