JPH0782252B2 - Resin composition for toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a resin composition for a toner. More specifically, it relates to a resin composition for a toner which gives a wide fixing temperature range to the toner.

[Prior Art] A method using a heat roller is widely used to fix an electrostatic latent image visualized with toner in electrophotography.

A wide fixing temperature range is desired in this method. The fixing temperature range is indicated by the difference (T _O −T _L ) between the temperature at which offset to the heat roller occurs (T _O ) and the minimum fixing temperature (T _L ).

Generally, when a polymer having a low molecular weight is used as a resin composition for toner, the lower limit temperature of fixing is low but the temperature at which offset occurs is also low. On the other hand, when a polymer having a high molecular weight is used as the resin composition for toner, on the contrary, there arises a problem that the offset temperature becomes high.

In order to meet these contradictory requirements, a polymer having a high molecular weight polymer portion and a low molecular weight polymer portion is used as a toner resin composition.

When the lower limit fixing temperature is low and the offset temperature is to be kept high, the molecular weight and weight fraction of each of the low molecular weight polymer portion and the high molecular weight polymer portion are adjusted to satisfy the required performance. Specifically, when the molecular weight of the low molecular weight polymer portion is increased, it is necessary to increase the weight fraction of the low molecular weight polymer portion in order to maintain the fixing lower limit temperature, and conversely when the weight fraction of the low molecular weight polymer portion is decreased. In order to keep the fixing lower limit temperature low, it is necessary to reduce the molecular weight of the low molecular weight portion.

[Problems to be Solved by the Invention] However, in the case of carrying out polymerization with an ordinary radical initiator for the purpose of sufficiently lowering the molecular weight of the above-mentioned low molecular weight polymer portion, the polymerization initiation is carried out with respect to 100 parts by weight of the polymerizable monomer. It requires 3 to 20 parts by weight of the agent. Therefore, when used as a resin composition for a toner having a large amount of polymerization initiator decomposing terminal residue at the molecular end of the obtained polymer, the charging property of the toner, the dependence on the charging environment, and the deterioration of storage stability are caused. It is not economically preferable to use a large amount of polymerization initiator.

Further, for the purpose of obtaining a low molecular weight polymer in which the decomposition terminal residue of the polymerization initiator is sufficiently small so as not to cause deterioration of the chargeability and storage stability of the toner, thermal polymerization at high temperature or a small amount of polymerization initiator at high temperature (Specifically, 0 to 1 part by weight of a polymerization initiator to 100 parts by weight of a polymerizable monomer) is used in combination to obtain a low molecular weight polymer having an ethylenically unsaturated double bond having a polymerization retarding effect at the molecular end. When a high molecular weight polymer is polymerized in the presence of a low molecular weight polymer containing a large amount of S, not only rubbing which causes a delay in the polymerization but also sufficient offset resistance performance that significantly reduces the degree of polymerization of the obtained high molecular weight polymer Can't get Especially in a system using a small amount of a polymerization initiator, a large amount of unreacted polymerizable monomer remains in the resulting polymer which causes a dead end of the polymerization, resulting in problems such as toxicity, odor generation and deterioration of storage stability. Becomes

[Means for Solving the Problems] The inventors of the present invention have made earnest studies on a resin composition for a toner that imparts a sufficiently low minimum fixing temperature and is excellent in toner chargeability, charge environment dependency, and storage stability. Invented.

That is, the present invention is a resin composition for a toner, characterized in that the following polymer (1) is dissolved in one or more polymerizable monomers (M1) containing styrene and then polymerized.

Polymer (1): a polymer (A) having a glass transition temperature of 30 to 90 ° C and a Lewis acid, which is obtained by polymerizing one or more polymerizable monomers (M2) containing styrene at 150 to 250 ° C. A polymer in which the double bond present in the polymer chain is substantially eliminated by reacting with.

In the present invention, the polymerizable monomers (M1) and (M2) include those in the same range, and each of (M1) and (M2) is 1
The constitution of one or more kinds of monomers may be the same or different.
Examples of (M1) and (M2) include styrene or a mixture thereof with a styrene monomer, a (meth) acrylic monomer, a maleic acid monomer and the like.

As the styrene-based monomer, a styrene substitution product (alkyl styrene such as α-methyl styrene, o-, m- or p-) is used.
-Methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, etc.) and the like.

Examples of the (meth) acrylic monomer include alkyl (meth) acrylate [alkyl having 1 to 18 carbon atoms, such as methyl (meth) acrylate, ethyl (meth) acrylate, n- or i-butyl (meth) acrylate. , N-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth)
Acrylate and stearyl (meth) acrylate], hydroxyl group-containing (meth) acrylate [hydroxylethyl (meth) acrylate, etc.] and the like. Of these, methyl (meth) acrylate, ethyl (meth) acrylate, n-
Or i-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and a mixture of two or more thereof.

Examples of the maleic acid-based monomer include maleic acid; maleic anhydride; and maleic acid derivatives such as maleic acid dialkyl esters (maleic acid butyl ester, maleic acid-2-ethylhexyl ester, etc.). Of these, maleic acid dialkyl esters are preferred.

Other polymerizable monomers such as amino group-containing monomers {amino group-containing (meth) acrylate [dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, etc.], amino group-containing (meth) acrylamide [N, N-dimethylacrylamide etc.]}, nitrile group-containing (meth) acrylic compounds (acrylonitrile etc.), (meth) acrylic acid, vinyl esters (vinyl acetate, vinyl propionate etc.), aliphatic hydrocarbon vinyl monomers (butadiene etc.) , Nitrile compounds (acrylonitrile, methacrylonitrile, etc.), vinyl ethers (vinyl methyl ether, vinyl ethyl ether,
Vinyl isobutyl ether, etc.), vinyl ketone (vinyl methyl ketone, vinyl hexyl ketone, etc.), N-vinyl compound (N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone, etc.), vinyl halide (chloride) Vinyl, etc.), di- or polyvinyl compounds (divinylbenzene, divinyltoluene, ethylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, etc.)] and the like. The polymerizable monomer (M1) preferably contains a (meth) acrylic monomer together with styrene.

The composition ratio of each polymerizable monomer in each of (M1) and (M2) is such that styrene is usually 30 to 100% by weight, preferably 50 to 100%.
weight%. The other polymerizable monomer is usually 0 to 70% by weight, preferably 0 to 50% by weight. When using a di- or polyvinyl compound, it is usually 3% by weight or less, preferably 1% by weight or less. If the styrene content is less than 30% by weight, it is disadvantageous in terms of toner grindability. When producing the polymer (A), a polymerization initiator can be used if necessary. As the polymerization initiator, oil-soluble peroxides (benzoyl peroxide, lauroyl peroxide, etc.), azo-based polymerization initiators (2,2′-gazobisisobutyronitrile, 2,2′-azobis (2,2 4-dimethylvaleronitrile etc.), etc. These may be used alone or in admixture of two or more.

The amount of the polymerization initiator used is usually 0 to 5%, preferably 0 to 2%, based on the total weight of the polymerizable monomer (M2). The smaller the amount of the polymerization initiator used, the easier it becomes to adjust the chargeability of the toner.

If necessary, a chain transfer agent can be used for the polymerization.
Examples of the chain transfer agent include mercaptan compounds, halogen compounds, α-methylstyrene dimer and the like.

The amount of chain transfer agent is usually 5% or less, preferably 1% or less, based on the total weight of (M2).

A solvent can be used for the polymerization if necessary. As the solvent, aromatic hydrocarbon solvents (toluene, xylene, etc.), chlorine-based solvents (chloroform, carbon tetrachloride, ethylene dichloride, ethylene tetrachloride, etc.), ether solvent systems, and mixed solvents of two or more of these are used. Can be mentioned.

The amount of solvent is usually 0 to 200% by weight, preferably 0 to 50% by weight, based on the total (M2).

A component composed of such a polymerizable monomer (M2) is supplied to the reactor to carry out polymerization. The polymerization temperature is usually 150 to 250 ° C, preferably 180 to 240 ° C. If the polymerization temperature is less than 150 ° C., a large amount of polymerization initiator is required to obtain a polymer having a sufficiently low molecular weight, which may affect the charging property of the toner. On the other hand, if the polymerization temperature exceeds 250 ° C, depolymerization of the polymer and increase in the formation of dimer to pentamer will occur, and the storage stability of the toner will be deteriorated.

After the above-mentioned polymerization, unreacted polymerizable monomer and / or solvent may be removed by a method such as heating under reduced pressure.

The glass transition temperature (hereinafter abbreviated as Tg) of the polymer (A) can be obtained by differential scanning calorimetry of a sample obtained by removing unreacted polymerizable monomer, solvent and the like by heating under reduced pressure. Tg is usually 30-90
C, preferably 50-80C. When it is lower than 30 ° C, the storage stability of the toner is lowered, and when it exceeds 90 ° C, the lower limit fixing temperature of the toner is raised.

The number average molecular weight of the polymer (A) is usually 1,000 to 15,000, preferably 1,500 to 10,000 and can be measured by gel permeation chromatography (polystyrene standard).

A Lewis acid is reacted with this polymer.

Examples of the Lewis acid include boron trifluoride, boron trifluoride complex (boron trifluoride ether complex, etc.), aluminum chloride, titanium tetrachloride, tin tetrachloride and the like. Of these, boron trifluoride and boron trifluoride ether complex are preferable.

If necessary, a cocatalyst may be used in the reaction with the Lewis acid. Examples of the cocatalyst include water, alcohol, acid (acetic acid, ethyl acetate, acetic anhydride, etc.), ether, halogen compound and the like. Of these, acetic acid and acetic anhydride are preferred.

If necessary, a solvent may be used in the reaction with the Lewis acid.
As the solvent, the above-mentioned solvent that can be used at the time of polymerization can be similarly used.

The amount of Lewis acid is usually 0.01 to 3% by weight, preferably 0.03 to 1% by weight, based on the weight of the polymerizable monomer (M2) before polymerization. If it is less than 0.01% by weight, the double bond existing in the polymer chain cannot be sufficiently eliminated, and if it exceeds 3% by weight, the polymer is colored.

The amount of cocatalyst is usually 0 to 10% by weight, preferably 0.01 to 5% by weight, based on the weight of (M2) before polymerization.

The amount of the solvent is usually 0 to 200% by weight, preferably 1 to 50% by weight, based on the weight of (M2) before the polymerization.

The reaction temperature with the Lewis acid is usually 40 to 200 ° C, preferably 60
~ 150 ° C. If the temperature is below 40 ° C, the reaction rate will be too low,
If it exceeds ℃, there is a problem such as coloring.

The disappearance of the double bond is due to the proton in the polymerized chloroform solution.
It can be confirmed by NMR measurement.

The composition of the present invention is obtained by dissolving and polymerizing the polymer (1) in which the double bond is substantially eliminated in the polymerizable monomer (M1).

Examples of this polymerization method include a method in which (1) is dissolved and then bulk polymerization or suspension polymerization, a method in which the polymerizable monomer (M1) is added dropwise to the heat-melted (1), and the like. Polymerization in each method can be carried out in the presence or absence of a polymerization initiator, a chain transfer agent or the like.

The amount of (1) when the polymer (1) is dissolved in the polymerizable monomer (M1) is usually 5 to 90%, preferably 15 to 80% based on the total weight of the resin composition of the present invention. To be 5%
If it is less than 100%, the lower limit fixing temperature is too high, and if it exceeds 90%, sufficient hot offset resistance cannot be obtained. The toner using the toner resin composition according to the present invention is used by being fixed to a support (paper, polyester film, etc.), and as a fixing method, known heat roll fixing method and pressure fixing method can be applied. Particularly, it can be preferably applied to a heat roll fixing method.

[Examples] Hereinafter, the present invention will be further described with reference to Examples, but the present invention is not limited thereto. Parts in the examples are parts by weight.

Synthesis Example 1 144 parts of styrene, 38 parts of methyl methacrylate and n-
A polymerizable monomer mixture of 18 parts of butyl acrylate was charged into a reactor equipped with a thermometer, a stirrer, a gas introduction tube and a cooling tube. The system was purged with nitrogen and then kept under a nitrogen atmosphere. The temperature was raised to 150 ° C. with stirring, and thereafter the system after thermal polymerization was adjusted to 205 ° C. by the heat of polymerization. A polymerizable monomer mixture of 576 parts of styrene, 152 parts of methyl methacrylate and 72 parts of n-butyl acrylate was added dropwise for polymerization to obtain a polymerization rate of 99.8%. Unreacted polymerizable monomers are removed by heating under reduced pressure to remove the polymer (A
-1) was obtained. The number average molecular weight was 9,800 and Tg was 66 ° C.

Synthesis Example 2 100 parts of xylene was charged into a pressure resistant reactor equipped with a stirrer, the system was replaced with nitrogen, and the pressure was reduced. The temperature was raised to 210 ° C., 100 parts of styrene was injected under pressure to carry out polymerization, and the reaction was carried out for 2 hours. Xylene and unreacted polymerizable monomers were removed by heating under reduced pressure to obtain a polymer (A-2). The number average molecular weight was 8,900 and Tg was 62 ° C.

Comparative Synthesis Example 3 920 parts of xylene was placed in a reactor equipped with a thermometer, a stirrer, a gas introduction tube and a cooling tube. The system was purged with nitrogen and then kept under a nitrogen atmosphere. The temperature was raised to reflux with xylene while stirring. 720 parts of styrene, 190 parts of methyl methacrylate, 90 parts of n-butyl acrylate, and 135 parts of di-t-butyl peroxide were added dropwise under reflux polymerization, and after completion of aging polymerization (polymerization rate of 99% or more), xylene was added by heating under reduced pressure. It was removed to obtain a polymer (A-3). Number average molecular weight 9,100, Tg 60 ℃
Met.

Example 1 600 parts of the polymer (A-1) and 400 parts of toluene were charged into a reactor equipped with a thermometer, a stirrer, a gas introduction tube and a cooling tube, and the system was replaced with nitrogen and thereafter kept under a nitrogen atmosphere. While stirring, the temperature was raised by heating and maintained at 90 ° C. 0.5 parts of boron trifluoride diethyl ether complex and 5 parts of acetic acid were added dropwise, and the mixture was reacted for 90 minutes and heated under reduced pressure to evaporate torunene to obtain a polymer (A-4).

Dissolve 333 parts of polymer (A-4) in 520 parts of styrene and 147 parts of n-butyl acrylate, add 3 parts of benzoyl peroxide, and add 2
After suspension polymerization for 1 hour, washing and drying were performed to obtain a resin composition for toner (B-1).

Example 2 600 parts of the polymer (A-2) and 400 parts of xylene were charged into a reactor equipped with a thermometer, a stirrer, a gas introduction tube and a cooling tube, and the system was replaced with nitrogen, and thereafter kept under a nitrogen atmosphere. While stirring, the temperature was raised by heating and maintained at 115 ° C. 0.5 parts of boron trifluoride diethyl ether complex and 2 parts of acetic anhydride were added dropwise, and after reacting for 90 minutes, they were heated under reduced pressure to distill off xylene. The temperature of the reactor was adjusted to 120 ° C, 310 parts of styrene and 90 parts of n-butylmethacrylate were added dropwise, and the reaction was heated to raise the temperature in 7 hours to complete the polymerization, and unreacted polymerizable monomer was removed under reduced pressure for toner. A resin composition (B-2) was obtained.

Comparative Example 1 520 parts of styrene and 147 parts of n-butyl acrylate were dissolved in 333 parts of the polymer (A-1), and 3 parts of benzoyl peroxide was added.
After suspension polymerization for 1 hour, the resin was washed and dried to obtain a toner resin composition (B-3). The toner resin composition (B-3) has Tg
At 38 ° C., the unreacted polymerizable monomer had a strong odor and could not withstand the following use as a toner resin composition.

Comparative Example 2 600 parts of the polymer (A-2) was charged into a thermometer, a stirrer, a reactor equipped with a gas introduction tube and a cooling tube, and the system was replaced with nitrogen, and thereafter kept under a nitrogen atmosphere. The contents were melted by heating up to 120 ° C. Styrene 310 parts, n-butyl methacrylate 9
0 part was added dropwise, and heating and temperature reaction were carried out for 7 hours to complete the polymerization, and unreacted polymerizable monomer was removed under reduced pressure to remove the toner resin composition (B
-4) was obtained.

Comparative Example 3 The polymer (A-4) of Example 1 was replaced with the polymer (A-3), and then the same procedure as in Example 1 was performed.
-5) was obtained.

Examples 1 and 2 Comparative Examples 2 and 3 Resin compositions for toner (B-1, B-2, B-
4 and B-5) were made into toner under the same conditions and fixing evaluation was carried out to obtain the results shown in Table 1.

[Effects of the Invention] The composition of the present invention is a resin composition for a toner that imparts excellent low-temperature fixability and hot offset resistance to the toner and does not cause fogging due to uneven charging.

Since it has the above effects, the resin composition for a toner of the present invention is useful for an electrophotographic toner.

Claims (6)

[Claims] 1. A resin composition for a toner, comprising the following polymer (1) dissolved and polymerized in one or more polymerizable monomers (M1) containing styrene. Polymer (1): a polymer (A) having a glass transition temperature of 30 to 90 ° C. and a Lewis acid, which is obtained by polymerizing one or more polymerizable monomers (M2) containing styrene at 150 to 250 ° C. A polymer in which the double bond present in the polymer chain is substantially eliminated by reacting with. 2. The composition according to claim 1, wherein the content of the polymer (1) is 15 to 80% by weight. 3. The composition according to claim 1, wherein the polymerization of (M2) is carried out in the presence of a polymerization initiator, and the amount of the polymerization initiator used is 5% by weight or less based on (M2). 4. The composition according to claim 1, wherein the polymerization of (M2) is carried out substantially without using a polymerization initiator. 5. The composition according to claim 1, wherein (M1) further contains a (meth) acrylic monomer. 6. The composition according to claim 1, wherein the polymer (A) has a number average molecular weight (polystyrene standard) of 1,500 to 10,000 as determined by gel permeation chromatography.