JP7066436B2 - Manufacturing method of external additive for toner - Google Patents

Description

The present invention relates to a method for producing an external additive for toner used in an electrophotographic method, an electrostatic recording method, a magnetic recording method, and the like.

In recent years, electrophotographic devices have been pursued to be faster than before. In addition, there is still a high demand for energy saving, and low temperature fixability of toner is very important. In response to such problems, various inventions have been made regarding the external additive existing on the surface layer of the toner particles.

For example, Patent Document 1 proposes a toner in which core-shell type composite particles in which the surface of resin fine particles is coated with silica are externally added. The feature of this method is that the durability is equivalent to that of the conventional external additive, and the inhibition of fixability can be reduced by using an organic substance. However, since the melting temperature of the external additive is higher than that of the parent particles, no effect on low temperature fixability can be expected.
In particular, in an electrophotographic apparatus having a high process speed for forming an electrophotographic image, it is necessary to increase the speed even in the fixing process. The faster fixing process means that the paper on which the unfixed toner is placed can receive heat from the fixing roller for a shorter time during heat fixing.

Japanese Unexamined Patent Publication No. 2012-1377 JP-A-2017-134398

How the toner particles can be melted to bond the toner particles to each other and / or the toner particles to the paper within this short heating time is important for improving the low temperature fixability.
Therefore, the present inventors can melt the surface of the toner particles even with a short heating time by externally adding a crystalline material to the surface of the toner particles so that the toner particles are present on the surface of the toner particles. Was considered to be able to be improved.
However, when particles coated with silica are produced as in Patent Document 2, it is difficult to increase the crystallinity of the crystalline resin, and the resin fine particles are aggregated and / or combined in the silica coating step. Unification occurred and it was difficult to prepare an external additive having a uniform particle size.
The present invention provides a method for producing an external additive for toner, which can solve the above problems.
Specifically, it provides a method for producing an external additive for toner, which has a high degree of crystallinity and a sharp particle size distribution.

The present invention
Fine particles containing crystalline material and
A coating layer containing an organosilicon condensate on the surface of the fine particles,
It is a method for manufacturing an external additive for toner, which is used to manufacture an external additive for toner.
The manufacturing method is
( A) A step of dissolving a crystalline material having an acid value of 5.0 mgKOH / g or more and 30.0 mgKOH / g or less in an organic solvent to prepare a crystalline material solution 1.
( B) A step of adding a neutralizing agent having a pKa of 7.0 or more to the crystalline material solution 1 to prepare the crystalline material solution 2.
( C) A step of adding an aqueous medium to the crystalline material dissolution liquid 2 to prepare a dispersion liquid A by phase inversion emulsification, and
( D) A step of forming a coating layer containing an organosilicon condensate on the surface of the fine particles by mixing the organosilicon compound with the dispersion A and causing the organosilicon compound to undergo a hydrolysis reaction and a condensation reaction.
Have,
After the step (c) and before the step (d), the pH of the dispersion A is adjusted to 4.0 or less.
The present invention relates to a method for producing an external additive for toner, which is characterized by the above.

According to the present invention, it is possible to provide a method for producing an external additive for toner, which has a high degree of crystallinity and a sharp particle size distribution.

In the present invention, the description of "○○ or more and XX or less" and "○○ to XX" indicating a numerical range means a numerical range including a lower limit and an upper limit which are end points, unless otherwise specified.
The crystalline material is a material in which an endothermic peak is observed in differential scanning calorimetry (DSC).

The method for producing an external additive for toner of the present invention (hereinafter, also simply referred to as a production method) is
Fine particles containing crystalline material and
A coating layer containing an organosilicon condensate on the surface of the fine particles,
It is a manufacturing method of an external additive for toner having
a) A step of dissolving a crystalline material having an acid value of 5.0 mgKOH / g or more and 30.0 mgKOH / g or less in an organic solvent to prepare a crystalline material solution 1.
b) A step of adding a neutralizing agent having a pKa of 7.0 or more to the crystalline material solution 1 to prepare the crystalline material solution 2.
c) A step of adding an aqueous medium to the crystalline material solution 2 to prepare a dispersion liquid A by phase inversion emulsification, and
d) A step of forming a coating layer containing an organosilicon condensate on the surface of the fine particles by mixing the organosilicon compound with the dispersion A and causing the organosilicon compound to undergo a hydrolysis reaction and a condensation reaction. It is characterized by including.

An external toner additive having a coating layer containing an organic silicon condensate on the surface of fine particles containing a crystalline material plasticizes the surface of the toner particles by melting the crystalline material during heating, and the toner particles and each other and / Or it is expected to bond the toner particles to the paper.
However, it is difficult to increase the crystallinity of the crystalline material by the conventional production method, and the amorphous portion having a low glass transition temperature tends to be exposed on the surface of the fine particles. As a result, in the step of forming the coating layer containing the organic silicon condensate, aggregation and / or coalescence of fine particles occurs, and an external additive having a uniform particle size (that is, a sharp particle size distribution) is produced. It is difficult to do.
In order to solve this, it is necessary to increase the crystallinity of the crystalline material as much as possible.
In order to increase the crystallinity of the crystalline material, it is required to reduce the amount of the surfactant and other auxiliaries used as much as possible when producing the fine particles.
The reason is that when a surfactant or other auxiliary agent is present in the fine particles, the crystalline material is easily plasticized, which causes a factor of lowering the crystallinity.

On the other hand, the external additive for toner also has a role of controlling the chargeability and adhesive force of the toner.
If the surface of the fine particles does not have a coating layer containing an organosilicon condensate, or if the coating layer is not uniform, it tends to cause a charge leak of toner and an increase in adhesive force.
In the production method of the present invention, the crystallinity of the crystalline material can be increased, and at the same time, homogenization of the coating layer containing the organosilicon condensate can be achieved.

The organic solvent used in step a) is not particularly limited as long as it is an organic solvent capable of dissolving the crystalline material. For example, tetrahydrofuran (THF), toluene, ethyl acetate, acetone, methyl ethyl ketone (MEK), hexane and the like can be used.

The crystalline material may include, but is not limited to, the following:
Crystalline polyester resin, crystalline acrylic resin, crystalline polyester resin having a urethane bond, crystalline resin such as a hybrid resin having a crystalline polyester moiety and an amorphous vinyl polymer moiety, wax and the like. These can also be used alone or in combination.

The melting point of the crystalline material is preferably 40 ° C. or higher and lower than 95 ° C., and more preferably 50 ° C. or higher and lower than 85 ° C.
When the melting point of the crystalline material is within the above range, when a coating layer containing an organic silicon condensate is formed on the surface of the fine particles, the high-temperature heat resistance and low-temperature meltability required as an external additive for toner are simultaneously satisfied. Can be done.

The acid value of the crystalline material is 5.0 mgKOH / g or more.
The acid value is preferably 7.0 mgKOH / g or more, and more preferably 10.0 mgKOH / g or more.
When the lower limit of the acid value is in the above range, the dispersibility of the crystalline material is improved with a small amount of a surfactant or a neutralizing agent, and the crystallinity of the crystalline material can be increased.
On the other hand, the acid value of the crystalline material is 30.0 mgKOH / g or less.
The acid value is preferably 28.0 mgKOH / g or less, and more preferably 25.0 mgKOH / g or less.
When the upper limit of the acid value is in the above range, the inhibition of crystallization by the acidic functional group is reduced, so that the degree of crystallization can be increased.
Further, the lower limit value and the upper limit value of the acid value can be arbitrarily combined.
The method for controlling the acid value of the crystalline material differs depending on the material, but can be controlled by the amount of the acid monomer in the crystalline material, the amount of the acidic functional group, and the like. The method for measuring the acid value of the crystalline material will be described later.

The fine particles may contain a material other than the crystalline material to the extent that the effect of the present invention is not impaired. Examples of the material include conventionally known materials used for toner.

In the step b), the acid value of the crystalline material in the crystalline material solution 1 is neutralized.
By neutralizing the acid value of the crystalline material, the dispersibility of the crystalline material in the crystalline material solution 1 and in the aqueous medium can be remarkably improved.
In order to neutralize the acidic functional groups contained in the crystalline material, a neutralizing agent is added to the crystalline material solution 1.
The neutralizing agent is not particularly limited as long as it can neutralize the acidic functional group contained in the crystalline material, but its pKa is 7.0 or more and 14.0 or less.
Further, the pKa of the neutralizing agent is preferably 8.5 or more and 13.0 or less, more preferably 9.0 or more and 12.5 or less, and further preferably 9.0 or more and 11.0 or less. preferable.
When the pKa of the neutralizing agent is in the above range, the dispersibility of the crystalline material in the crystalline material solution 1 becomes good, so that the emulsification at the time of phase inversion becomes uniform, and the prepared external addition for toner. The particle size distribution of the agent becomes sharp.
When the neutralizing agent is not added or when the pKa of the neutralizing agent is less than 7.0, the particle size distribution of the produced external additive for toner becomes broad. If the amount of the surfactant or other auxiliary agent added to the aqueous medium is increased in order to prevent this, it becomes a factor that lowers the crystallinity of the crystalline material.

Examples of the neutralizing agent include, but are not limited to, the following compounds.
Aminemic water, N-methyl-ethanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, N-methyl-diethanolamine, bis-hydroxypropyl-methylamine , Tri-n-butylamine, bis-2-hydroxypropylamine, N-methyl-ethanolamine, 2-amino-2-methyl-1-propanol, 3-amino-1-propanol, 1-amino-2-propanol, Amines such as 2-amino-2-hydroxymethyl-1,3-propanediol, 2-amino-2-methyl-1,3-propanediol, cyclohexylamine, n-butylamine, t-butylamine, and N-methylmorpholin. , Salts of weak and strong bases such as sodium carbonate and potassium carbonate, hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide.

The boiling point of the neutralizing agent is preferably 180 ° C. or lower, more preferably 150 ° C. or lower, and even more preferably 130 ° C. or lower.
When the boiling point of the neutralizing agent is within the above range, the difference between the crystallization temperature and the melting temperature in the crystalline material becomes small, and the crystallinity of the produced external additive for toner becomes high.
It is considered that this is because the content of the neutralizing agent remaining inside the produced toner external additive is reduced.
If the neutralizing agent remains in the coating film after drying and curing, it affects the physical characteristics of the coating film. Therefore, it is preferable that the neutralizing agent volatilizes and does not remain after drying and curing.
From the above viewpoint, the neutralizing agent is preferably as shown below. The temperature in parentheses indicates the boiling point.
Aminemic water (-33 ° C), N-methyl-ethanolamine (155 ° C), N, N-dimethylethanolamine (133 ° C), N, N-diethylethanolamine (161 ° C), triethylamine (90 ° C), ethanol Amine (170 ° C), 2-amino-2-methyl-1-propanol (165 ° C), 1-amino-2-propanol (160 ° C), 2-amino-2-methyl-1,3-propanediol (151 ° C) Amines such as (° C.), cyclohexylamine (135 ° C.), t-butylamine (78 ° C.), N-methylmorpholine (115 ° C.).

In the step c), an aqueous medium is added to the crystalline material dissolution liquid 2 and a dispersion liquid A is prepared by phase inversion emulsification.
Other methods of producing particles, such as forced emulsification, require the use of large amounts of surfactant, while phase inversion emulsification does not require the use of large amounts of surfactant, resulting in crystals of crystalline material. It is possible to increase the degree of crystallinity.
The water-based medium is not particularly limited, and a medium such as water may be used.
The phase inversion emulsification is also not particularly limited, and an aqueous medium is applied to 100 parts by mass of the crystalline material solution 2 in a state of being heated to a temperature at which the crystalline material does not precipitate from the crystalline material solution 2. It is preferable to stir and mix at an addition amount of about 200 parts by mass or more and 400 parts by mass or less and an addition rate of 0.1 parts by mass or more and 0.5 parts by mass or less.

In the step b), a surfactant or other auxiliary agent may be added after the addition of the neutralizing agent, but it is preferable to reduce the amount used as much as possible.
The surfactant is not particularly limited, but is preferably an anionic surfactant. Specifically, carboxylates such as sodium octanate, sodium decanoate, sodium laurate, sodium myristate, sodium stearate; sodium 1-decane sulfonate, sodium 1-dodecane sulfonate, sodium octylbenzene sulfonate, etc. Sulfates such as sodium lauryl sulphate, sodium myristyl sulphate, sodium polyoxyethylene alkylphenol sulphonate, ammonium lauryl sulphate;
The amount of the surfactant added is preferably 0.40 parts by mass or less, more preferably 0.30 parts by mass or less, and 0. It is more preferably 20 parts by mass or less, and particularly preferably substantially 0.

In step d), a known method can be used to form a coating layer containing an organosilicon condensate on the surface of the fine particles.
For example, a method using an organosilicon compound can be mentioned.
Specifically, it is advisable to add an organosilicon compound such as a silane coupling agent to the dispersion liquid A prepared in step c).
Then, in the dispersion liquid A, the organosilicon compound can undergo a hydrolysis reaction and a condensation reaction, and a coating layer containing the organosilicon condensate can be formed on the surface of the fine particles by hydrophobic interaction.
The coating layer may completely cover the surface of the fine particles, or the surface of a part of the fine particles may be exposed.
However, from the viewpoint of toner charge leakage and adhesive force, it is preferable that the coating layer containing the organosilicon condensate is uniform.
In the present invention, the uniformity of the coating layer is expressed by the difference between the maximum thickness and the minimum thickness of the coating layer in the toner external additive photographed by using a transmission electron microscope.
The difference between the maximum thickness and the minimum thickness of the coating layer is preferably less than 30 nm, more preferably less than 25 nm, and even more preferably less than 20 nm.
The details of the method for measuring the thickness of the coating layer and the method for evaluating the uniformity of the coating layer will be described later.

Prior to the step d), it is preferable to adjust the pH of the dispersion to 5.0 or less by using hydrochloric acid or the like. The pH is more preferably adjusted to 4.0 or less, and even more preferably 3.0 or less. On the other hand, the pH is preferably about 1.0 or higher.
When the pH is in this range, the reaction rates of the hydrolysis reaction and the condensation reaction become appropriate, and the organic silicon condensate is uniformly coated.

The organosilicon compound is preferably an organosilicon compound represented by the following formula (1).
Si [R ¹ _X (OR ² ) _Y (R ³ Q) _Z ] (1)
Further, the coating layer preferably contains an organosilicon condensate formed by condensing the organosilicon compound.
In the above formula (1), X + Y + Z = 4, X is 0 or 1, Y is an integer of 2 to 4 (preferably 2 to 3), and Z is 0 to 2 (preferably 1 to 2). Is an integer of.
Further, R ¹ is a hydrogen atom or an alkyl group (preferably having 1 to 4 carbon atoms).
^R2 is a methyl group or an ethyl group
R ³ is an alkylene group having 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms).
Q is a substituted or unsubstituted vinyl group, acryloyloxy group, or methacryloyloxy group.
By using the organosilicon compound represented by the formula (1), the organosilicon condensate can form a strong coating layer on the surface of the fine particles, so that the coalescence of the obtained particles is reduced and the particle size is uniform. It is possible to prepare an external preparation having the above.

Further, as the organosilicon compound, it is also possible to use an organosilicon compound having a polymerizable functional group. When an organic silicon compound having a polymerizable functional group is subjected to a hydrolysis reaction and a depolymerization reaction to form a coating layer containing the organic silicon decomplex polymer on the surface of fine particles, a stronger organic silicon depolymerized polymer can be obtained. It is possible to form a coated surface layer. Forming a strong coating layer has the effect of improving durability when a force is applied.
The organic silicon shrunk polymer is an organic silicon condensate and forms a shrunk polymer in which a polymerizable functional group is polymerized.
Examples of the polymerizable organosilicon compound include an organosilicon compound represented by the following formula (2).
Si [R ¹ _X (OR ² ) _Y (R ³ Q) _Z ] (2)
In the above equation (2), X + Y + Z = 4, X is 0 or 1, Y is an integer of 2 to 3, and Z is an integer of 1 to 2.
Further, R ¹ is a hydrogen atom or an alkyl group (preferably having 1 to 4 carbon atoms).
^R2 is a methyl group or an ethyl group
R ³ is an alkylene group having 1 to 10 carbon atoms (preferably 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms).
Q is a substituted or unsubstituted vinyl group, acryloyloxy group, or methacryloyloxy group.
In the polymerization reaction using the polymerizable functional group, it is preferable to proceed the polymerization on the surface of the fine particles by adding a radical polymerization initiator such as potassium persulfate. As the conditions for the polymerization reaction, conventionally known reaction conditions may be used.

When a crystalline polyester resin is used as the crystalline material, the following diols can be used for the production thereof, but the present invention is not limited thereto.
1,4-Butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1, , 11-Undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, 1,20-eicosandiol and other saturated aliphatic diols;
Unsaturated aliphatic diols such as 2-butene-1,4-diol, 3-hexene-1,6-diol, 4-octene-1,8-diol.
These can also be used alone or in combination.

On the other hand, the following acid components can be used in the production of the crystalline polyester resin, but the present invention is not limited thereto.
Glyric acid, malonic acid, amber acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, 1,9-nonandicarboxylic acid, 1,10-decandicarboxylic acid, 1,11-undecandicarboxylic acid, Saturated aliphatic carboxylic acids such as 1,12-dodecanedicarboxylic acid, 1,13-tridecanedicarboxylic acid, 1,14-tetradecanedicarboxylic acid and 1,18-octadecanedicarboxylic acid;
Unsaturated aliphatic carboxylic acids such as fumaric acid, maleic acid, 3-hexendioic acid, 3-octendioic acid;
Aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid;
Tricarboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,4-cyclohexanetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, pyromellitic acid; and lower alkyl esters thereof. , And acid anhydrides.
These can also be used alone or in combination.

The crystalline polyester resin preferably has a urethane bond.
When a crystalline polyester resin having a urethane bond is used as the crystalline material, the elasticity of the toner when a large amount of heat is applied during fixing increases, which is very effective in improving the fixing unevenness.
Examples of the isocyanate component for forming the urethane bond include the following.
Aromatic diisocyanates having 6 or more and 20 or less carbon atoms (excluding carbons in NCO groups, the same applies hereinafter), aliphatic diisocyanates having 2 or more and 18 or less carbon atoms, alicyclic diisocyanates having 4 or more and 15 or less carbon atoms, and these diisocyanates. Modified products (modified products containing urethane group, carbodiimide group, allophanate group, urea group, burette group, uretdione group, uretoimine group, isocyanurate group, oxazolidone group; hereinafter also referred to as modified diisocyanate), and two or more of these. blend.
Examples of the aromatic diisocyanate include the following.
m- and / or p-xylylene diisocyanate (XDI), α, α, α', α'-tetramethylxylylene diisocyanate.
Examples of the aliphatic diisocyanate include the following.
Ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate.
Examples of the alicyclic diisocyanate include the following.
Isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate.
Among these, aromatic diisocyanates having 6 to 15 carbon atoms, aliphatic diisocyanates having 4 to 12 carbon atoms, and alicyclic diisocyanates having 4 to 15 carbon atoms are preferable. More preferably, it is HDI, IPDI, and XDI.
Further, in addition to the diisocyanate, a trifunctional or higher functional isocyanate compound can also be used.

The method for producing the crystalline polyester resin is not particularly limited, and the crystalline polyester resin can be produced by a general method in which the acid component and the diol component are reacted.
For example, depending on the type of monomer, direct polycondensation or transesterification method can be appropriately used for production.
In the production method, the polymerization temperature is preferably between 180 ° C. and 230 ° C. or lower, and it is preferable to reduce the pressure in the reaction system as necessary to remove water and alcohol generated during condensation.
If the monomer dissolves or does not dissolve at the reaction temperature, it is preferable to add a solvent having a high boiling point as a dissolution aid to dissolve the monomer.
The polycondensation reaction may be carried out while distilling off the dissolution auxiliary solvent. When a monomer having poor compatibility is present in the copolymerization reaction, it is preferable to condense the monomer having poor compatibility with the monomer and an acid or diol to be polycondensed in advance, and then polycondensate with the main component.
Examples of the catalyst that can be used in the production include a titanium catalyst and a tin catalyst.
Examples of the titanium catalyst include titanium tetraethoxydo, titanium tetrapropoxide, titanium tetraisopropoxide, titanium tetrabutoxide and the like.
Examples of the tin catalyst include dibutyltin dichloride, dibutyltin oxide, and diphenyltin oxide.

When wax is used as a crystalline material, for example, the following can be mentioned.
Esters of monovalent alcohols and aliphatic monocarboxylic acids such as behenyl behenate, stearyl stearate, palmityl palmitate, or esters of monovalent carboxylic acids and aliphatic monoalcohols;
Esters of divalent alcohols and aliphatic monocarboxylic acids such as dibehenyl sebacate, hexanediol dibehenate, or esters of divalent carboxylic acids and aliphatic monoalcohols;
Esters of trihydric alcohols and aliphatic monocarboxylic acids such as glycerin tribehenate, or esters of trivalent carboxylic acids and aliphatic alcohols;
Esters of tetrahydric alcohols and aliphatic monocarboxylic acids such as pentaerythritol tetrastearate, pentaerythritol tetrapalmitate, or esters of tetravalent carboxylic acids and aliphatic monoalcohols;
Esters of hexahydric alcohols and aliphatic monocarboxylic acids such as dipentaerythritol hexastearate, dipentaerythritol hexapalmitate, or esters of hexavalent carboxylic acids and aliphatic monoalcohols;
Esters of polyhydric alcohols and aliphatic monocarboxylic acids such as polyglycerin behenate, or esters of polyhydric carboxylic acids and aliphatic monoalcohols;
Natural ester waxes such as carnauba wax and rice wax;
Petroleum waxes such as paraffin wax, microcrystalline wax, petrolatum and their derivatives;
Hydrocarbon wax by Fischer-Tropsch method and its derivatives;
Polyolefin waxes such as polyethylene wax, polypropylene wax and derivatives thereof.

Examples of the wax include a modified wax obtained by acid-modifying or alcohol-modifying an aliphatic hydrocarbon-based wax.
The modified wax may include 0-valent, monovalent, and divalent or higher, and the mixture of modified wax contains 40 mass of monovalent (monocarboxylic acid or monoalcohol) modified wax. It is preferable that it is contained in% or more. More preferably, it is contained in an amount of 50% by mass or more.
Examples of the acid-modified aliphatic hydrocarbon-based wax include those obtained by acid-modifying polyethylene or polypropylene with a monovalent unsaturated carboxylic acid such as acrylic acid. The melting point of the acid-modified wax can be controlled by the molecular weight.

The surface of the organosilicon condensate may be further treated with silicone oil. By treating with silicone oil, the hydrophobicity of the external additive can be further enhanced. This makes it possible to obtain a toner having stable developability even in a high temperature and high humidity environment.

As the surface treatment method with the silicone oil, a known method may be used.
As the silicone oil, one having a viscosity at 25 ° C. of 30 mm ² / s or more and 1000 mm ² / s or less is used. Specific examples of such silicone oil include dimethyl silicone oil, methyl phenyl silicone oil, α-methyl styrene modified silicone oil, chlorphenyl silicone oil, fluorine-modified silicone oil and the like. Examples of the method for treating silicone oil include the following methods. A method of directly mixing silica fine particles treated with a silane coupling agent and silicone oil using a mixer such as a Henschel mixer. A method of spraying silicone oil on the base silica fine particles. Alternatively, a method in which the silicone oil is dissolved or dispersed in an appropriate solvent, and then silica fine particles are added and mixed to remove the solvent is more preferable.

Next, a method for measuring each physical property according to the present invention will be described.
<Measurement method of acid value>
The acid value is the number of mg of potassium hydroxide required to neutralize the acid contained in 1 g of the sample.
The acid value of the resin is measured according to JIS K 0070-1992. Specifically, the following procedure is followed.
(1-1) Preparation of Reagents A phenolphthalein solution is prepared by dissolving 1.0 g of phenolphthalein in 90 mL of ethyl alcohol (95% by volume) and adding ion-exchanged water to make the liquid volume 100 mL.
Dissolve 7 g of special grade potassium hydroxide in 5 mL of water and add ethyl alcohol (95% by volume) to make the liquid volume 1 L. Next, put this solution in an alkali-resistant container so as not to come into contact with carbon dioxide gas or the like, leave it for 3 days, and then filter it to prepare a potassium hydroxide solution.
The factor of the potassium hydroxide solution was the hydroxylation required for neutralization when 25 mL of 0.1 mol / L hydrochloric acid was taken in a triangular flask, several drops of phenolphthalein solution were added, and titration was performed with the potassium hydroxide solution. Obtained from the amount of potassium solution. The 0.1 mol / L hydrochloric acid used at this time is prepared according to JIS K 8001-1998.
(1-2) Operation (A) Main test 2.0 g of the crushed sample is precisely weighed in a 200 mL Erlenmeyer flask, 100 mL of a mixed solution of toluene: ethanol (2: 1) is added, and the mixture is dissolved over 5 hours.
Then, a few drops of phenolphthalein solution are added as an indicator, and titration is performed using a potassium hydroxide solution. The end point of the titration is when the light red color of the indicator continues for about 30 seconds. (B) Blank test Titration is performed in the same manner as above except that no sample is used (that is, only a mixed solution of toluene: ethanol (2: 1) is used).
(1-3)
Substitute the obtained result into the following formula to calculate the acid value.
A = [(CB) x f x 5.61] / S
In the formula, A represents the acid value (mgKOH / g), B represents the addition amount (mL) of the potassium hydroxide solution in the blank test, and C represents the addition amount (mL) of the potassium hydroxide solution in the main test. ).
f represents the factor of the potassium hydroxide solution, and S represents the mass (g) of the sample.

<pH measurement method>
Weigh 0.100 g of a sample into a 250 mL tall beaker, add 150 mL of water, and dissolve over 30 minutes to obtain a measurement solution. A pH electrode is placed in the measurement solution and the pH is read to obtain the pH of the sample. The temperature of the measurement solution is 30 ° C.

<Measurement method of pKa>
Weigh 0.100 g of a sample into a 250 mL tall beaker, add 150 mL of water, and dissolve over 30 minutes to obtain a measurement solution. Add 10 μL each of 0.1 mol / L potassium hydroxide ethyl alcohol solution (manufactured by Kishida Chemical Co., Ltd.), and perform titration while reading the pH each time.
Add 0.1 mol / L potassium hydroxide ethyl alcohol solution until the pH becomes 10 or more and the pH does not change even if 30 μL is added.
From the obtained results, the pH with respect to the addition amount of 0.1 mol / L potassium hydroxide ethyl alcohol solution is plotted to obtain a titration curve.
From the obtained titration curve, the point where the gradient of pH change is the largest is set as the neutralization point, and half the amount of 0.1 mol / L potassium hydroxide ethyl alcohol solution required up to the neutralization point is used. The pH is read from the titration curve, and the read pH value is defined as pKa. The temperature of the measurement solution is 30 ° C.

<Measurement method of peak molecular weight of crystalline material>
The peak molecular weight (Mp) of the crystalline material is measured by gel permeation chromatography (GPC) as follows.
First, the sample is dissolved in toluene at 50 ° C. for 24 hours. Then, the obtained solution is filtered through a solvent-resistant membrane filter "Maeshori Disc" (manufactured by Tosoh Corporation) having a pore diameter of 0.2 μm to obtain a sample solution. The sample solution is adjusted so that the concentration of the component soluble in toluene is about 0.8% by mass. This sample solution is used for measurement under the following conditions.
Equipment: HLC8120 GPC (detector: RI) (manufactured by Tosoh Corporation)
Column: 7 stations of Shodex KF-801, 802, 803, 804, 805, 806, 807 (manufactured by Showa Denko KK)
Eluent: Toluene flow rate: 1.0 mL / min
Oven temperature: 40.0 ° C
Sample injection volume: 0.10 mL
In calculating the molecular weight of the sample, standard polystyrene resin (trade names "TSK Standard Polystyrene F-850, F-450, F-288, F-128, F-80, F-40, F-20, F-10," A molecular weight calibration curve created using F-4, F-2, F-1, A-5000, A-2500, A-1000, A-500 ", manufactured by Toso Co., Ltd.) is used.

<Evaluation of number average particle size (Dp), volume average particle size (Dv), and particle size uniformity of the toner external additive>
The number average diameter (Dp) and volume average diameter (Dv) of the toner external additive are measured using a zetasizer "Nano-ZS" (manufactured by MALVERN).
First, as a sample, fine particles to be measured are dispersed in a dispersion medium to prepare a dispersion liquid. The obtained dispersion liquid is diluted with a dispersion medium so that the solid-liquid ratio is 0.10% by mass (± 0.02% by mass), collected in a quartz cell, and placed in a measuring unit.
As the dispersion medium, methyl ethyl ketone is used for the inorganic fine particles, and water is used for the organic fine particles and the external additive for toner.
As the measurement conditions, the refractive index of the sample, the refractive index of the dispersion medium, the viscosity and the temperature are input and measured by the control software "ZETASIZER SOFTWARE 6.30". DN is adopted as the number average particle size (Dp).
The refractive index of the inorganic fine particles is adopted from the Chemical Handbook.
As the refractive index of the organic fine particles, the refractive index of the material used for the organic fine particles is adopted from the refractive index built in the control software.
However, if there is no built-in refractive index, the value described in the National Institute for Materials Science Polymer Database is used.
The refractive index of the external additive for toner is calculated by taking the weight average from the refractive index of the inorganic fine particles and the refractive index of the material used for the organic fine particles.
For the refractive index, viscosity and temperature of the dispersion medium, select the numerical values built in the control software. In the case of mixed media, the weight average of the dispersion media to be mixed is taken.
The particle size uniformity is calculated from the following formula.
(Particle size uniformity) = Dv / Dp

<Evaluation of melting point of crystalline material and melting temperature of toner external additive>
The melting point of the crystalline material and the melting temperature of the toner external additive are measured using a differential scanning calorimeter "Q1000" (manufactured by TA Instruments) according to ASTM D3418-82.
The melting point of indium and zinc is used for temperature correction of the device detector, and the heat of fusion of indium is used for the correction of calorific value.
Specifically, 1 mg of a sample is precisely weighed, placed in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed in the measurement range of 20 ° C to 140 ° C with the following settings. ..
・ Temperature rise and fall rate 10 ℃ / min
・ After raising the temperature from 20 ° C to 140 ° C, the temperature is lowered from 140 ° C to 20 ° C. Further, the temperature is re-heated from 20 ° C. to 140 ° C. In this re-heating process, a specific heat change is obtained in the temperature range of 20 ° C. to 140 ° C. The melting point of the crystalline material and the melting temperature of the toner external additive are taken as the peak temperature of the maximum endothermic peak in the specific heat change curve.

<Evaluation of crystallinity of toner external additive>
The crystallinity of the toner external additive is measured using a differential scanning calorimetry device "Q1000" (manufactured by TA Instruments).
The melting point of indium and zinc is used for temperature correction of the device detector, and the heat of fusion of indium is used for the correction of calorific value.
Specifically, 1 mg of a sample is precisely weighed, placed in an aluminum pan, and an empty aluminum pan is used as a reference, and measurement is performed in the measurement range of 20 ° C to 140 ° C with the following settings. ..
・ Temperature rise and fall rate 10 ℃ / min
・ After raising the temperature from 20 ° C to 140 ° C, the temperature is lowered from 140 ° C to 20 ° C.
In this temperature lowering process, a specific heat change is obtained in the temperature range of 140 ° C. to 20 ° C. The crystallization temperature (Tc: ° C.) is the temperature of the maximum exothermic peak in the specific heat change curve.
From the melting point of the toner external additive and the crystallization temperature, the index of crystallization degree is obtained using the following formula.
The smaller the value obtained by the following formula, the higher the crystallinity.
(Crystallinity) = (melting point)-(crystallization temperature)

<Evaluation of the thickness of the coating layer containing the organosilicon condensate and the uniformity of the coating layer>
The thickness of the coating layer containing the organosilicon condensate is calculated using a transmission electron microscope (TEM) H-700H, H-800, or H-7500 (all manufactured by Hitachi, Ltd.). A transmission electron microscope can be used to distinguish between a coating layer containing an organosilicon condensate and an internal crystalline material.
The toner external additive is photographed at 20,000 times or more and 100,000 times or less, and the sample is observed at an arbitrary magnification with a baking magnification of 1 times or more and 5 times or less.
Particles having a diameter of 30 nm or more are selected, the thicknesses of the coating layers at 10 locations are measured in 36 degree increments, and the arithmetic mean value thereof is taken as the average value A1 of the coating layer of the particles. Here, the coating layer is measured by confirming between the internal crystalline material and the organosilicon condensate from the TEM image.
The same measurement is performed with 20 randomly selected toner external additives, and the average values A2 to A20 are calculated for each. From A1 to A20 calculated here, the thickness of the coating layer and the uniformity of the coating layer are calculated by the following formulas.
(Thickness of coating layer) = (A1 + A2 + ... + A20) ÷ 20
(Uniformity of coating layer) = (maximum value of A1 to A20)-(minimum value of A1 to A20)

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" and "%" of each material in Examples and Comparative Examples are all based on mass.

<Production example of crystalline material 1>
・ (Acid component) sebacic acid 116.0 parts ・ (Acid component) Trimellitic acid 12.5 parts ・ (Alcohol component) 1,6-hexanediol 55.7 parts Equipped with a stirrer, thermometer, and nitrogen introduction tube The above raw materials were charged in the reaction vessel.
Subsequently, 0.1% by mass of titanium tetraisopropoxide was added to the total amount of the above raw materials, reacted at 180 ° C. for 4 hours, heated to 210 ° C. at 10 ° C./1 hour, and 8 at 210 ° C. After holding for a long time, the reaction was carried out at 8.3 kPa for 1 hour to obtain a crystalline polyester resin.
Subsequently, the crystalline polyester resin was charged in a reaction vessel equipped with a stirrer, a thermometer, and a nitrogen introduction tube. 14 parts of hexamethylene diisocyanate (HDI) was added as an isocyanate component with respect to the total amount of the acid component and the alcohol component.
Tetrahydrofuran (THF) was added thereto so that the concentrations of the crystalline polyester resin and HDI were 50% by mass.
The urethanization reaction was carried out over 10 hours by heating to 50 ° C.
The solvent THF was distilled off to obtain a crystalline material 1.
The presence or absence of urethane bond in the crystalline material 1 was confirmed by the following method.
Equipment: Frontier (Fourier transform infrared spectroscopic analyzer, manufactured by PerkinElmer) equipped with Universal ATR Sampleing Accessory (universal ATR measurement accessory)
ATR crystal: Ge ATR crystal (refractive index = 4.0)
The FT-IR spectrum by the ATR method had a peak top at 1528 cm ^-1 , and it was confirmed that it had a urethane bond.
Table 2 shows the acid value, melting point, and peak molecular weight (Mp) of the crystalline material 1.

<Production examples of crystalline materials 2 to 6>
Crystalline materials 2 to 6 were obtained in the same manner as in the production example of the crystalline material 1 except that the monomer formulation and the isocyanate component were changed as shown in Table 1 and the reaction conditions were adjusted.
Table 2 shows the physical properties of the crystalline materials 2 to 6.

<Production example of wax 1 (hereinafter, also referred to as crystalline material 7)>
By condensing 1,6-hexanediol and behenic acid, 1,6-hexanediol dibehenate (acid value 7.0 mgKOH / g, melting point 82 ° C.) was obtained.

<Production example of wax 2 (hereinafter, also referred to as crystalline material 8)>
Maleic anhydride-modified polyethylene (acid value 32.0 mgKOH / g, melting point 44 ° C.) was obtained by modifying polyethylene with maleic anhydride.

<Production example of amorphous material 1>
In a container with a stirrer substituted with nitrogen, 3 parts of soft dodecylbenzenesulfonic acid was dissolved in 150 parts of ion-exchanged water, and then 95 parts of styrene was emulsified to prepare a polymerizable monomer emulsion.
After raising the temperature of the emulsion to 80 ° C., 0.6 part of potassium persulfate dissolved in 10 parts of ion-exchanged water was added and polymerized for 2 hours.
Subsequently, after the temperature of the reaction product was lowered to 40 ° C., 5 parts of divinylbenzene was added and the mixture was stirred for 2 hours.
Then, the temperature was raised to 85 ° C., 0.1 part of potassium persulfate dissolved in 2 parts of water was added, a polymerization reaction was carried out for 4 hours, and an aqueous hydroquinone solution was added as a reaction terminator to complete the polymerization. The polymerization conversion rate at this time was 99%. Water-soluble substances were removed by ultrafiltration.
The concentration of the emulsion was adjusted to obtain an emulsion of the amorphous material 1 having a solid content concentration of 50% by mass.

<Example 1>
In a reaction vessel equipped with a stirrer, a condenser, a thermometer, and a nitrogen introduction tube, 5 parts of crystalline material 1 and 10 parts of methyl ethyl ketone (MEK) were charged and heated to 50 ° C. to dissolve.
Then, with stirring, 0.45 parts of triethylamine is added.
After confirming that the crystalline material is sufficiently dissolved, 40 parts of water is added dropwise at a rate of 2.5 parts / minute for phase inversion emulsification, whereby the fine particle dispersion liquid 1 (solid content concentration 9.0) is added. Mass%) was obtained.
MEK was sufficiently distilled off by an evaporator at 60 ° C.
Here, the pH of the fine particle dispersion 1 was 9.0. The pH was measured while dropping 0.1 mol / L hydrochloric acid into the fine particle dispersion 1, and the pH was adjusted to 2.0.
15 parts of methacryloxypropyltrimethoxysilane (MPTMS) was added to 10 parts of the fine particle dispersion, and the mixture was heated at 65 ° C. for 30 minutes.
Then, 1.5 parts of a 10% by mass aqueous solution of potassium sulfate was added and heated at 80 ° C. for 3 hours to promote hydrolysis and polycondensation to prepare a coating layer containing an organic silicon polymer.
Then, it cooled and dried to obtain the external additive 1. The following evaluation was carried out using the obtained external additive. The evaluation results are shown in Table 4.

<Examples 2 to 18>
External preparations 2 to 18 were obtained in the same manner as in Example 1 except for the changes shown in Table 3-1 and Table 3-2. Table 4 shows various physical characteristics of the obtained external additive.
In Examples 9 to 18, 0.04 part of sodium lauryl sulfate was added in step b). Hereinafter, Examples 10 to 18 will be referred to as Reference Examples 10 to 18, respectively.

<Comparative Example 1>
Comparative external additive 1 was obtained in the same manner as in Example 1 except for the changes shown in Table 3-1 and Table 3-2. Table 4 shows various physical characteristics of the obtained external additive.
In Comparative Example 1, 10 parts of the emulsion of the amorphous material 1 is used. Further, in step b), 0.40 part of sodium lauryl sulfate is added without using a neutralizing agent.

<Comparative Example 2>
The comparative external additive 2 was obtained in the same manner as in the production example of Example 1 except for the changes shown in Table 3-1 and Table 3-2. Table 4 shows various physical characteristics of the obtained comparative external additive 2. In Comparative Example 2, in step b), 0.40 part of sodium lauryl sulfate was added without using a neutralizing agent.

<Manufacturing example of Comparative Example 3>
Comparative external additive 3 was obtained in the same manner as in Example 1 except for the changes shown in Table 3-1 and Table 3-2. Table 4 shows various physical characteristics of the obtained comparative external additive 3.
In Comparative Example 3, 0.08 part of sodium lauryl sulfate was added in step b) without using a neutralizing agent.
Further, in step c), forced emulsification was performed according to the following procedure. That is, after confirming that the crystalline material 1 is sufficiently dissolved, the crystalline material 1 dissolution solution is added to 40 parts of water while stirring, and the mixture is dispersed with an ultrasonic homogenizer for 5 minutes (intermittent irradiation: irradiation 1s, Stopped 1s).

<Manufacturing examples of Comparative Examples 4 to 6>
Comparative external additives 4 to 6 were obtained in the same manner as in Example 1 except for the changes shown in Table 3-1 and Table 3-2. Table 4 shows various physical characteristics of the obtained comparative external additives 4 to 6.
The organosilica sol used in Comparative Example 6 is an organosilica sol (MEK-ST-40, manufactured by Nissan Chemical Industries, Ltd.).

The criteria for each evaluation are shown below.
<Evaluation of particle size uniformity>
(Evaluation criteria)
A: Particle size uniformity is less than 1.80 B: Particle size uniformity is 1.80 or more and less than 2.30 C: Particle size uniformity is 2.30 or more and less than 2.80 D: Particle size uniformity is 2.80 or more

<Evaluation of melting temperature>
(Evaluation criteria)
A: Melting temperature is 50 ° C or more and less than 70 ° C B: Melting temperature is 45 ° C or more and less than 50 ° C or 70 ° C or more and less than 90 ° C C: Melting temperature is 40 ° C or more and less than 45 ° C or 90 ° C or more and less than 110 ° C D: Melting The temperature is less than 40 ° C or 110 ° C or higher

<Evaluation of crystallinity>
(Evaluation criteria)
A: Crystallinity is less than 35 B: Crystallinity is 35 or more and less than 45 C: Crystallinity is 45 or more and less than 55 D: Crystallinity is 55 or more

<Evaluation of uniformity of coating layer>
(Evaluation criteria)
A: Uniformity of the coating layer is less than 15 nm B: Uniformity of the coating layer is 15 nm or more and less than 25 nm C: Uniformity of the coating layer is 25 nm or more and less than 35 nm D: Uniformity of the coating layer is 35 nm or more

Claims (7)

Fine particles containing crystalline material and
A coating layer containing an organosilicon condensate on the surface of the fine particles,
It is a method for manufacturing an external additive for toner, which is used to manufacture an external additive for toner.
The manufacturing method is
( A) A step of dissolving a crystalline material having an acid value of 5.0 mgKOH / g or more and 30.0 mgKOH / g or less in an organic solvent to prepare a crystalline material solution 1.
( B) A step of adding a neutralizing agent having a pKa of 7.0 or more to the crystalline material solution 1 to prepare the crystalline material solution 2.
( C) A step of adding an aqueous medium to the crystalline material dissolution liquid 2 to prepare a dispersion liquid A by phase inversion emulsification, and
( D) A step of forming a coating layer containing an organosilicon condensate on the surface of the fine particles by mixing the organosilicon compound with the dispersion A and causing the organosilicon compound to undergo a hydrolysis reaction and a condensation reaction.
Have,
After the step (c) and before the step (d), the pH of the dispersion A is adjusted to 4.0 or less.
A method for manufacturing an external additive for toner, which is characterized by the above. In the step ( d), the organosilicon compound represented by the following formula (1) is mixed with the dispersion A, and the organosilicon compound is allowed to undergo a hydrolysis reaction and a condensation reaction, thereby forming the surface of the fine particles. The method for producing an external additive for toner according to claim 1, which is a step of forming a coating layer containing the organosilicon condensate.
Si [R ¹ _X (OR ² ) _Y (R ³ Q) _Z ] (1)
(In the formula (1), X + Y + Z = 4, X is 0 or 1, Y is an integer of 2 to 4, Z is an integer of 0 to 2, and R ¹ is a hydrogen atom or an alkyl group. R ² is a methyl group or an ethyl group, R ³ is an alkylene group having 1 to 10 carbon atoms, and Q is a substituted or unsubstituted vinyl group, an acryloyloxy group, or a methacryloyloxy group. ) In the step ( d), the organic silicon compound represented by the following formula (2) is mixed with the dispersion liquid A, and the organic silicon compound is allowed to undergo a hydrolysis reaction and a polypolymerization reaction, whereby the surface of the fine particles is formed. The method for producing an external additive for toner according to claim 1 or 2, which is a step of forming a coating layer containing the organic silicon condensate.
Si [R ¹ _X (OR ² ) _Y (R ³ Q) _Z ] (2)
(In the formula (1), X + Y + Z = 4, X is 0 or 1, Y is an integer of 2 to 3, Z is an integer of 1 to 2, and R ¹ is a hydrogen atom or an alkyl group. R ² is a methyl group or an ethyl group, R ³ is an alkylene group having 1 to 10 carbon atoms, and Q is a substituted or unsubstituted vinyl group, an acryloyloxy group, or a methacryloyloxy group. ) The method for producing an external additive for toner according to any one of claims 1 to 3, wherein the pKa of the neutralizing agent is 9.0 or more and 11.0 or less. The method for producing an external additive for toner according to any one of claims 1 to 4 , wherein the neutralizing agent has a boiling point of 130 ° C. or lower. The method for producing an external additive for toner according to any one of claims 1 to 5 , wherein the crystalline material is a crystalline resin. The method for producing an external additive for toner according to claim 6 , wherein the crystalline resin is a crystalline polyester resin.