JPH0615586B2 - Non-aqueous resin dispersion - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a non-aqueous resin dispersion liquid which is particularly useful for applications such as toners, printing inks, paints and adhesives for electrostatographic liquid developers.

BACKGROUND ART Non-aqueous resin dispersions can be used in various applications such as electrostatic photography liquid developers and printing inks. Considering their use in liquid developers, however, electrostatic photography liquid developers are well known. As described above, a toner mainly composed of a colorant and a resin is dispersed in a carrier liquid such as an aliphatic hydrocarbon solvent. It is known that a cross-linking resin is preferably used as the toner resin in the wet development transfer system using such a liquid developer in order to improve transfer efficiency. Further, this crosslinked resin has an advantage that it can be produced in one step when polymerized with a monomer having two or more vinyl groups in one molecule. Conventionally, such a crosslinked resin is produced by solution polymerization of a monomer having a vinyl group in the presence of a polymerization initiator according to a conventional method. However, it is difficult to make a stable product in a solution, and there is a large variation in products between manufacturing lots. Moreover, the crosslinked resin obtained by the conventional method has insufficient stability and redispersibility when a pigment such as carbon black is dispersed.

A first object of the present invention is to provide a crosslinked resin dispersion liquid in which the viscosity is easily controlled by performing the crosslinking reaction in the copolymer solution and the product variation between the production lots is small. .

A second object of the present invention is to provide a crosslinked resin dispersion which is excellent in dispersion stability and redispersibility when a pigment is dispersed.

The composition of the non-aqueous resin dispersion of the present invention is at least represented by the general formula I in a non-aqueous solvent containing an aliphatic hydrocarbon solvent as a main component. [Where R is -H or -CH _3, R 'is -COOCmH ₂ m _{+ 1} or -OCOCmH ₂ m ₊ 1 (m is 6-20 of integral) Monomer A and formula II represented by (Wherein R is —H or —CH ₃ , n is an integer of 1 to 10) and a polymerizable monomer C having a carboxyl group are polymerized.

The present inventors have made various studies as to what kind of properties (resin) should be used in order to achieve all the above-mentioned objects, and have reached the following conclusions. That is, the properties of this polymer are 1) a solvating component is present in the polymer, and this polymer has a uniform cross-linking structure, 2) a cross-linking monomer component in which the cross-linking reaction does not occur too rapidly is included, 3 ) It contains a monomer component such that the copolymerization reaction and the crosslinking reaction occur separately, 4) it has an affinity for the pigment, and 5) it does not dissolve in a non-aqueous solvent, and therefore, simply in a non-aqueous solvent. It can be dispersed. Therefore, as a result of exploring various polymers from these viewpoints, the present inventors have found that a monomer that can be a solvating agent before and after polymerization and a monomer A such as the unsaturated compound of the general formula I that can be a crosslinking component after the polymerization. A copolymer obtained by a crosslinking reaction by a step of subjecting the monomer B of the general formula II to a copolymerization reaction, and further by an esterification reaction of the glycidyl group of the monomer B and the polymerizable monomer C containing a carboxyl group is optimal. I found that there is. The present invention is based on such knowledge.

In order to prepare the cross-linked copolymer resin dispersion of the present invention, generally, the above-mentioned monomer A and monomer B are generally benzoyl peroxide in a solvent mainly containing an aliphatic hydrocarbon,
A glycidyl group-containing copolymer is produced by heat-polymerizing at about 60 to 150 ° C. in the presence of a polymerization initiator such as azobisisobutyronitrile, and then this copolymer and a monomer C having a carboxyl group are combined with pyridine, The esterification reaction may be carried out in the presence of a basic catalyst such as amine to crosslink.

Here, the monomer A / monomer B / monomer C ratio is 50 to
99.5 / 0.5 to 50 / 0.5 to 50 (weight) is suitable, and the amount of the polymerization initiator is suitably 0.1 to 5% (weight) of the amount of the monomer used in each step.

Further, in the present invention, other polymerizable monomer, silica fine particles, wax or polyolefin having a softening point of about 60 to 130 ° C. can be added to the step of producing the copolymer dispersion.
When silica fine particles are used, the copolymer is considered to be obtained in a state where the silica fine particles are incorporated in the crosslinked structure. In this case, it is considered that the silica itself does not undergo any physical change such as dissolution during the reaction. In any case, in the case of silica, the dispersion stability can be further improved by making the specific gravity approximate to that of the aliphatic hydrocarbon that is the dispersion medium and preventing the copolymer from gelling. On the other hand, when wax or polyolefin is used, it is dissolved in the reaction system by heating during the polymerization reaction, but after the reaction, it is precipitated in the form of particles by cooling, so that the copolymer is obtained in a state of being adsorbed on these fine particles. It is considered to be a thing. Here, wax or polyethylene has a specific gravity similar to that of the dispersion medium and prevents gelation of the copolymer, and since the molecular structure is similar to that of the dispersion medium, it not only helps to improve dispersion stability but also has a low softening point. Therefore, it also helps improve adhesion.
The amount of silica, wax or polyolefin added is appropriately about 5 to 50 parts by weight per 100 parts by weight of the copolymer.

Next, each material used in the present invention will be described.

First, as specific examples of the monomer A of the general formula I, lauryl methacrylate, lauryl acrylate, stearyl methacrylate, stearyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate, dodecyl methacrylate, dodecyl acrylate,
Examples thereof include cyclohexyl acrylate, cyclohexyl methacrylate, hexyl methacrylate, hexyl acrylate, octyl methacrylate, octyl acrylate, cetyl methacrylate, cetyl acrylate, vinyl laurate and vinyl stearate.

Specific examples of the monomer B of the general formula II include the following.

As the polymerizable monomer C having a carboxyl group, acrylic acid, methacrylic acid, fumaric acid, itaconic acid, maleic acid, 2-methacryloyloxyethyl succinic acid, 2-
Methacryloyloxyethyl maleic acid, 2-methacryloyloxyethyl phthalic acid, 2-hetacryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl maleic acid, 2-acryloyloxyethyl phthalic acid, 2-
Examples thereof include acryloyloxyethyl hexahydrophthalic acid.

As a polymerization initiator for low-temperature polymerization, azobisisobutyronitrile, benzoyldimethylaniline peroxide,
There are diethyl zinc, hydrogen peroxide and the like, and those for high temperature polymerization include benzoyl peroxide, lauryl peroxide, t-butyl peroxide, di-t-butyl peroxide, cumene hydroperoxide and dicumyl peroxide. is there.

Examples of the aliphatic hydrocarbon used as the reaction solvent include kerosene, ligroin, cyclohexane, n-hexane, n
-Pentane, n-heptane, n-octane, isooctane, isododecane, isononane (these commercial products are Isopar H, G, L, K; Exxon H; G, L, K; Naphtha No. 6)
And Ciel Sole Oil Co., Ltd.), carbon tetrachloride, perchlorethylene, perfluoroethylene and the like. These aliphatic hydrocarbons are high-insulating (electrical resistance 10 ¹⁰ Ω · cm or more) and low dielectric constant (dielectric constant 3 or less) nutrient media. When used as a carrier liquid in these aliphatic solvents, a small amount of an aromatic solvent such as benzene or toluene can be added.

In the present invention, other polymerizable monomers, wax-like substances and the like can be added in the step of producing the copolymer dispersion, but other polymerizable monomers include styrene, vinyltoluene, nitrostyrene, vinyl acetate, vinylpyrrolidone and dimethylamino. Examples thereof include ethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate and diethylaminoethyl acrylate.

Specific examples of commercially available wax or polyolefin having a softening point of 60 to 130 ° C. are as follows.

Polyethylene example Example of wax (paraffin wax) Examples of the present invention will be shown below.

Example 1 500 g of kerosene was charged into a flask of 3 equipped with a stirrer, a thermometer, a condenser and a dropping funnel, heated to 85 ° C., and stirred while lauryl acrylate 10 was added thereto.
0 g, No. 1 monomer B (50 g) and azobisisobutyronitrile (5 g) were added dropwise by a dropping funnel over 2 hours. After that, a polymerization reaction was carried out at this temperature for 4 hours under stirring, 10 g of methacrylic acid, 0.1 g of triethylamine and 0.01 g of hydroquinone were added, and the mixture was reacted at 80 ° C. for 20 hours. Next, 3 g of di-t-butyl peroxide was added,
Polymerization reaction was continued at 110 ° C. for 3 hours to obtain a resin dispersion having a polymerization rate of 93.8% and a viscosity of 330 _cp .

Example 2 400 g of n-hexane was put into the flask used in Example 1, heated to 60 ° C., 95 g of 2-ethylhexyl methacrylate, 25 g of No. 4 monomer B and 2 g of azobisisobutyronitrile were added dropwise while stirring. By 1
The solution was added dropwise over a period of time and then polymerized at this temperature for 6 hours. Next, acrylic acid 12.5g, hydroquinone 0.01
g and 0.2 g of pyridine were added and reacted at 80 ° C. for 20 hours. Further, add 4 g of benzoyl peroxide, and add 90 ° C.
By further performing a polymerization reaction under stirring for 4 hours, a resin dispersion having a polymerization rate of 98.1% and a viscosity of 260 cp was obtained.

Example 3 400 g of Isopar G was placed in the flask used in Example 1, heated to 90 ° C. and stirred while stearyl methacrylate 200 g, No. 6 monomer B 10 g, itaconic acid 6 g and benzoyl peroxide 3 g were added by a dropping funnel. Dropwise over time. Next, 30 g of styrene and 3 g of benzoyl peroxide were added, and the polymerization reaction was carried out at the above temperature for 4 hours with stirring, and the polymerization rate was 96% and the viscosity was 3%.
A 80 cp non-aqueous resin dispersion was obtained.

Example 4 200 g of Isopar G and 50 g of polyethylene (AC polyethylene 1106 manufactured by Allied Chemical Co., Ltd.) were placed in the flask used in Example 1 and heated to 90 ° C. to dissolve the polyethylene. 50g of No. 9 Monomer B in this
And 10 g of azobisisobutyronitrile were added dropwise with a dropping funnel over 2 hours, and the mixture was stirred at the above temperature for 6 hours.
The polymerization reaction was carried out for a time. Next, cetyl methacrylate 100
g, 2-methacryloyloxyethyl maleic acid 10 g
And t-butyl peroxide (5 g) were added, and further 130
Polymerization was carried out under stirring at ℃ for 6 hours, then diethylamine
0.2 g was added and an esterification reaction was carried out at 80 ° C. for 24 hours to obtain a polyethylene-containing resin dispersion liquid having a polymerization rate of 96.5% and a viscosity of 660 cp.

Example 5 AC polyethylene 61 was added to the fat dispersion liquid obtained in Example 2.
13 g was added, and the mixture was heated and dissolved at 90 ° C. for 2 hours and then allowed to cool to produce a polyethylene-containing resin dispersion having a viscosity of 290 cp.

Example 6 To the polyethylene-containing resin dispersion obtained in Example 4, 40 g of Sanwax 131-P was added, and the mixture was heated and dissolved at 90 ° C. for 2 hours, and then allowed to cool to produce a wax- and polyethylene-containing resin dispersion having a viscosity of 980 cp. did.

As described above, according to the present invention, by using the three specific monomers in combination, the viscosity can be easily controlled, the product variation between the production lots is small, and the pigment is dispersed. A non-aqueous resin dispersion having excellent dispersion stability and redispersibility can be obtained.

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08L 31/02 LHK 6904-4J 33/08 LJF 7921-4J // G03G 9/13

Claims (1)

[Claims] 1. A compound of at least general formula I in a non-aqueous solvent based on an aliphatic hydrocarbon solvent. [Where R is -H or -CH _3, R 'is -COOCmH ₂ m _{+ 1} or -OCOmH ₂ m ₊ 1 (m is 6-20 of integral) Monomer A and formula II represented by (Wherein R is —H or —CH ₃ , n is an integer of 1 to 10) and a non-hydrogen resin dispersion liquid obtained by polymerizing a polymerizable monomer C having a carboxyl group.