JP4038145B2 - Binder resin for toner - Google Patents

Description

【００４１】
【表２】

【００４２】
実施例１〜１２及び比較例１〜６（実施例８は参考例である）
表３に示す結着樹脂１００重量部、カーボンブラック「ＭＯＧＵＬ−Ｌ」（キャボット社製）４重量部及びポリエチレンワックス「ＳＰ−１０５」（サゾール社製、融点：１０５℃）０．５重量部をヘンシェルミキサーで十分混合した後、ロール内加熱温度１００℃の同方向回転二軸押出し機を用いて溶融混練し、得られた混練物を冷却、粗粉砕した後、ジェットミルにて粉砕し、分級して、体積平均粒径８．０μｍの粉体を得た。
【００４３】
得られた粉体１００重量部に外添剤として疎水性シリカ「ＴＳ−５３０」（キャボット社製、平均粒子径：８ｎｍ）０．１重量部を添加し、ヘンシェルミキサーで混合することにより、粉体に表面処理を施してトナーを得た。
【００４４】
試験例１〔耐環境性〕
ステンレス製の現像ロールを装備した非磁性一成分現像装置「ページプレストＮ−４」（カシオ計算機社製）にトナーを実装し、４０℃、９０％の高温高湿環境下で５００枚の画像を得た。５０枚目と５００枚目の画像の画像濃度を透過型マクベス濃度計「ＴＲ−９２７」を用いて測定し、以下の評価基準に従って、耐環境性を評価した。結果を表３に示す。
【００４５】
〔評価基準〕
５００枚目の画像濃度／５０枚目の画像濃度の値が、
◎：０．９５以上
○：０．８５以上、０．９５未満
×：０．８５未満
【００４６】
試験例２〔耐久性〕
トナー３重量部と平均粒子径９０μｍのシリコーンフェライトキャリア（関東電化工業社製）９７重量部とを混合して得られた二成分現像剤を、「プリテール５５０」（リコー社製）に実装し、印字率５％の画像を１０時間連続印刷した後、現像剤を取りだし、目開きが３２μｍの篩を用いてトナーを吸引し、キャリアのみを残存させる。残存したキャリアの炭素量を炭素分析装置「ＥＭＩＡ‐１１０」（堀場製作所製）を用いて測定し、あらかじめトナーと混合する前に測定しておいたキャリアの炭素量との差を求め、耐久性として評価した。結果を表３に示す。すなわち、炭素量の差が大きいほど、キャリアに多量のトナーが付着しており、トナーの耐久性が低いと判断できる。
【００４７】
〔評価基準〕
連続印刷前後のキャリアの炭素量の差が
◎：０．０５以下
○：０．０５〜０．１
×：０．１以上
【００４８】
【表３】

【００４９】
以上の結果より、実施例のトナーは、いずれも、粉砕性、耐環境性及び耐久性のいずれにおいても良好な結果が得られていることが分かる。
これに対し、
▲１▼ 比較例１では、低粉砕性指数樹脂の酸価が高いため、耐環境性が低下していること、
▲２▼ 比較例２、４では、低粉砕性指数樹脂と高粉砕性指数樹脂の粉砕性が近いために、トナーを製造する際の粉砕面が不安定となり、耐環境性が低下するともに、微粉の発生による耐久性の低下も生じていること、
▲３▼ 比較例３では、高粉砕性指数樹脂の酸価をアルコール成分の増量により調整しているために、未反応アルコール成分の多量の残存により耐久性が低下していること、
▲４▼ 比較例５では、結着樹脂として酸価の高い高粉砕性指数樹脂のみを含有しているため、耐環境性が低下していること、
▲５▼ 比較例６では、結着樹脂として酸価の低い低粉砕性指数樹脂のみを含有しているため、耐久性が低下していること
がそれぞれ分かる。
【００５０】
【発明の効果】
本発明により、粉砕性及び耐久性を損なうことなく、耐環境性に優れたトナー及び該トナーに用いられるトナー用結着樹脂を提供することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention is used as a binder resin for a toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and contains a binder resin for toner and the binder resin. It relates to toner.
[0002]
[Prior art]
As the versatility of copiers increases, there is a demand for a toner with good environmental resistance that can produce a clear image under the severe conditions of high temperature and high humidity or low temperature and low humidity as in the normal environment. In particular, polyesters are liable to have low environmental resistance due to the presence of terminal functional groups, particularly carboxyl groups, and improvement thereof is desired. As a countermeasure, it is conceivable to lower the acid value by increasing the molecular weight or increasing the alcohol component, but in the former case, the pulverization property and fixability are likely to decrease due to the increase in gel content, and in the latter case, the carrier is affected by the unreacted alcohol. Spent increases and durability tends to decrease. Further, simply using a resin with good pulverizability does not improve the durability. In addition, adjustment of cross-linking point density (see Patent Document 1), hybridization with vinyl resin (see Patent Document 2), adjustment of grindability index (see Patent Document 3), etc. have been studied, but further improvement is desired. It is rare.
[0003]
[Patent Document 1]
JP-A-7-140710 (Claim 1)
[Patent Document 2]
JP-A-7-98517 (Claim 1)
[Patent Document 3]
JP-A-8-30027 (Claim 1)
[0004]
[Problems to be solved by the invention]
An object of the present invention is to provide a toner excellent in environmental resistance and a binder resin for toner used in the toner without impairing pulverization and durability.
[0005]
[Means for Solving the Problems]
The present invention
(1) A binder resin for toner comprising two kinds of resins having different grindability indexes of 5 or more, wherein the acid value of the resin having a lower grindability index (low grindability index resin) is 10 mgKOH / g And a binder resin for toner in which the acid value of the resin having a higher grindability index (high grindability index resin) is 15 mgKOH / g or more, and (2) the toner binder resin and the colorant It relates to the toner.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The binder resin for toner of the present invention contains two kinds of resins each having a specific acid value and different grindability indexes, and the use of such a binder resin impairs grindability and durability. Thus, the environmental resistance of the toner can be improved. This is a combination of a resin having a low pulverization index and a low acid value that is easily pulverized, and a resin having a high pulverization index and a high acid value that is difficult to pulverize, and is melt-kneaded together with a colorant as a binder resin. When the toner is crushed into toner, it is presumed that the toner particle surface has a low acid value because it is easily pulverized at a resin part having a low pulverizability index, and the environmental resistance is improved without impairing the pulverizability and durability. The
[0007]
From the above viewpoint, the difference in grindability index between two types of resins having different grindability indices is 5 or more, preferably 5 to 20, more preferably 8 to 18. The grindability index of the low grindability index resin is preferably 2-20, more preferably 5-15, and the grindability index of the high grindability index resin is preferably 10-40, more preferably 15-35.
[0008]
The acid value of the low grindability index resin is 10 mgKOH / g or less, preferably 2 to 10 mgKOH / g, and the acid value of the high grindability index resin is 15 mgKOH / g or more, preferably 15 to 40 mgKOH / g. g.
[0009]
The softening point of the low grindability index resin is preferably 75 to 130 ° C, more preferably 85 to 115 ° C, and the glass transition point is preferably 55 to 70 ° C.
[0010]
The softening point of the high grindability index resin is preferably 135 to 170 ° C, more preferably 145 to 160 ° C, the glass transition point is preferably 60 to 80 ° C, and the chloroform insoluble content is preferably 5 to 50% by weight, 10 to 35% by weight is more preferable.
[0011]
The grindability index, softening point, and glass transition point of the resin can be adjusted by the monomer species and their ratio, the degree of crosslinking, the molecular weight, and the like.
[0012]
Examples of the two resins having different grindability indexes contained in the binder resin of the present invention include polyester, styrene-acrylic resin, epoxy resin, polycarbonate, polyurethane, and the like. Particularly required polyesters are preferable because the effects of the present invention are more remarkably exhibited.
[0013]
The low grindability index resin is preferably a linear resin, and the high grindability index resin is preferably a non-linear resin. In the present invention, the linear resin has a crosslinkable monomer content of less than 0.05 mol%, preferably 0 mol% in all monomers, and the non-linear resin has a valence of 3 or more. The monomer content is 0.05 to 40 mol%, preferably 1 to 35 mol%, and more preferably 3 to 30 mol% in all monomers. In addition, a crosslinkable monomer means the monomer which can make resin three-dimensional, for example in the case of vinyl resin, divinylbenzene, and polyester, such as trimellitic acid.
[0014]
As a raw material monomer for polyester, a known divalent or higher valent alcohol component and a known carboxylic acid component such as a divalent or higher carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used. The trihydric or higher alcohol component and the trivalent or higher carboxylic acid component correspond to the crosslinkable monomer.
[0015]
Examples of the divalent alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) Alkylene (2 to 3 carbon atoms) oxide adducts of bisphenol A such as propane, ethylene glycol, 1,2-propylene glycol, 1,4-butanediol, neopentyl glycol, polyethylene glycol, polypropylene glycol, hydrogenated bisphenol A, etc. Is mentioned.
[0016]
Examples of the trihydric or higher polyhydric alcohol include sorbitol, pentaerythritol, glycerin, trimethylolpropane and the like.
[0017]
Examples of the divalent carboxylic acid component include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, and other aliphatic carboxylic acids; dodecenyl succinic acid, octyl succinic acid Succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms such as: aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; anhydrides of these acids and their Alkyl (C1-C3) ester of acid etc. are mentioned. In particular, in the case of a low grindability index resin, aromatic dicarboxylic acids are preferable among them, and the content thereof is preferably 10 to 100 mol%, more preferably 50 to 100 mol% in the divalent carboxylic acid component. preferable.
[0018]
Examples of the trivalent or higher polyvalent carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid and acid anhydrides thereof, and lower alkyl. (C1-C3) ester etc. are mentioned.
[0019]
Polyester, for example, polycondensates an alcohol component and a carboxylic acid component at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst such as a tin-based catalyst or a titanium-based catalyst. Can be manufactured.
[0020]
The weight ratio of the high grindability index resin to the low grindability index resin (high grindability index resin / low grindability index resin) is preferably 60/40 to 98/2, and more preferably 70/30 to 90/10.
[0021]
Each of the high grindability index resin and the low grindability index resin may be a mixture of a plurality of resins.
[0022]
Furthermore, a toner containing the binder resin and the colorant of the present invention is provided.
[0023]
As the colorant, all of dyes and pigments used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Disazo Yellow and the like can be used alone or in combination of two or more. In the present invention, the toner is black toner, color Either toner or full color toner may be used. The content of the colorant is preferably 1 to 40 parts by weight and more preferably 3 to 10 parts by weight with respect to 100 parts by weight of the binder resin.
[0024]
The toner of the present invention further includes a charge control agent, a release agent, a conductivity modifier, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, a fluidity improver, and an improved cleaning property. An additive such as an agent may be appropriately contained.
[0025]
Charge control agents include nigrosine dyes, triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salt compounds, polyamine resins, imidazole derivatives and other positively chargeable charge control agents and metal-containing azo dyes, copper Examples include negatively chargeable charge control agents such as phthalocyanine dyes, metal complexes of alkyl derivatives of salicylic acid, and boron complexes of benzylic acid.
[0026]
Examples of the release agent include natural ester waxes such as carnauba wax and rice wax, synthetic waxes such as polypropylene wax, polyethylene wax, and Fischer Tropu, coal waxes such as montan wax, and waxes such as alcohol waxes. These may be contained alone or in admixture of two or more.
[0027]
The toner of the present invention is preferably a pulverized toner obtained by a kneading pulverization method. For example, after a binder resin, a colorant and the like are uniformly mixed with a mixer such as a Henschel mixer or a ball mill, It can be produced by melt-kneading with a monoaxial or biaxial extruder or the like, cooling, crushing, and classifying. At this time, as the binder resin, two kinds of resins having different grindability indexes may be used for mixing with a colorant or the like, respectively, and further, a mixture obtained by stirring and mixing two kinds of resins or two kinds of resins may be used. A step of melt-kneading and a binder resin obtained by pulverizing a kneaded product obtained by the melt-kneading step may be used. The volume average particle diameter of the toner is preferably 3 to 15 μm. A fluidity improver such as hydrophobic silica may be further externally added to the surface of the toner.
[0028]
When the toner of the present invention contains a magnetic fine powder, it is used alone as a developer, and when it does not contain a magnetic fine powder, it is used as a non-magnetic one-component developer or mixed with a carrier to develop a two-component developer. It can be used as an agent.
[0029]
【Example】
[Softening point]
Using a Koka type flow tester (manufactured by Shimadzu Corporation, CFT-500), a 1 g sample was heated at a heating rate of 6 ° C./min, a load of 1.96 Mpa was applied by a plunger, a diameter of 1 mm, A nozzle with a length of 1 mm is pushed out, and this draws a plunger drop amount (flow value) -temperature curve of the flow tester. When the height of the S-shaped curve is h, the temperature corresponding to h / 2 (resin The temperature at which half of the effluent flowed out) is taken as the softening point.
[0030]
[Glass transition point]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the sample was heated to 200 ° C., and the sample cooled to 0 ° C. at a temperature decrease rate of 10 ° C./min was measured at a temperature increase rate of 10 ° C./min. The temperature at the intersection of the base line extension below the maximum peak temperature and the tangent showing the maximum slope from the peak rising portion to the peak apex is defined as the glass transition point.
[0031]
[Chloroform insoluble matter]
(1) A resin sample was finely pulverized, and 5.0 g of a sample powder that passed through a 42 mesh (mesh opening: 355 μm) sieve was collected. The collected sample powder is put into a 150 ml container together with 5.0 g of filter aid (radiolite), and 100 g of chloroform is poured into this container, placed on a ball mill carrier and rotated for 5 hours. Dissolve.
(2) On the other hand, after placing a filter paper (No. 2) having a diameter of 7 cm in a pressure filter, pre-coating radiolite on it, adding a small amount of chloroform and bringing the filter paper into close contact with the filter, The contents in the container are poured into a filter. Further, the container is thoroughly washed with 100 ml of chloroform and poured into a filter so that deposits do not remain on the wall of the container.
(3) Close the upper lid of the filter and perform filtration. Filtration is performed under a pressure of 4 kg / cm ³ or less. After the outflow of chloroform is completed, the inside of the filter is washed with 100 ml of chloroform, followed by pressure filtration.
[0032]
(4) After filtration, all of the filter paper, the residue on it and radiolite are placed on an aluminum foil and placed in a vacuum dryer, and dried at a temperature of 85 ° C. and a pressure of 100 mmHg for 10 hours. The weight is calculated, and the weight ratio is calculated as the insoluble matter of chloroform.
[0033]
(Crushability index)
The resin is roughly crushed and passed through a sieve with mesh openings of 1 mm and 710 μm. A crushed material accumulated on a mesh having a mesh opening of 710 μm, that is, 20 g of a crushed material having a particle diameter of 710 μm or more and 1 mm or less, was pulverized for 10 seconds using a coffee mill (National CARIOCA-MILL MK-51M). The crushed crushed material is sieved with a mesh having an opening of 500 μm, and the ratio of the weight of the crushed material remaining on the lower mesh (g) / 20 × 100
The value calculated from is taken as the grindability index.
[0034]
Resin Production Example 1 (Resin L-1, L-3, L-5, L-6)
The amount of each raw material shown in Table 1 is put into a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and the reaction rate reaches 90% at 230 ° C. in a nitrogen atmosphere. And then reacted to a desired softening point at 8.3 kPa to obtain resins L-1, L-3, L-5, and L-6. In the present invention, the reaction rate means a value of reaction water amount (mol) / theoretical water generation amount (mol) × 100.
[0035]
Resin Production Example 2 (Resin L-2, L-7)
Among the raw materials used in Table 1, raw materials other than fumaric acid and hydroquinone were placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and under a nitrogen atmosphere, After reacting at 230 ° C. until the reaction rate reached 90%, the reaction was performed at 8.3 kPa for 1 hour. Thereafter, the mixture is cooled to 180 ° C., fumaric acid and hydroquinone are added, the temperature is raised to 210 ° C. over 3 hours, the reaction is carried out for 1 hour, and the reaction is carried out to the desired softening point at 8.3 kPa. L-2 and L-7 were obtained.
[0036]
Resin Production Example 3 (Resin L-4)
Put each amount of raw materials shown in Table 1 into a 5 liter four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer and thermocouple, and in a nitrogen atmosphere from 180 ° C to 210 ° C over 3 hours. After raising the temperature and allowing the reaction to proceed for 1 hour, the reaction was allowed to proceed to a desired softening point at 8.3 kPa to obtain Resin L-4.
[0037]
Resin production example 4 (resins H-1, H-4, H-5, H-7)
Of the raw materials shown in Table 2, raw materials other than fumaric acid, hydroquinone, and trimellitic anhydride are placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple. The reaction was allowed to proceed at 230 ° C. until the reaction rate reached 90%, and then reacted at 8.3 kPa for 1 hour. Then, it is cooled to 180 ° C., fumaric acid, trimellitic anhydride and hydroquinone are added, heated to 210 ° C. over 3 hours, reacted for 1 hour, and then to the desired softening point at 8.3 kPa. Reaction was carried out to obtain resins H-1, H-4, H-5, and H-7.
[0038]
Resin production example 5 (resins H-2, H-3, H-8)
Of the raw materials shown in Table 2, raw materials other than trimellitic anhydride are placed in a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and reacted at 230 ° C. in a nitrogen atmosphere. After reacting until the rate reached 90%, the reaction was performed at 8.3 kPa for 1 hour. Thereafter, it is cooled to 210 ° C. and trimellitic anhydride is reacted at room temperature for 1 hour, and then reacted to a desired softening point at 8.3 kPa to obtain resins H-2, H-3, and H-8. Obtained.
[0039]
Resin Production Example 6 (Resin H-6)
Each raw material other than the use amount of trimellitic anhydride shown in Table 2 is put into a 5-liter four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and 180 ° C. to 210 ° C. in a nitrogen atmosphere. The temperature was raised to 0 ° C. over 3 hours and reacted for 1 hour, and then reacted at 8.3 kPa for 1 hour. Thereafter, trimellitic anhydride was added and reacted at room temperature for 1 hour, and then reacted to a desired softening point at 8.3 kPa to obtain Resin H-6.
[0040]
[Table 1]

[0041]
[Table 2]

[0042]
Examples 1-12 and Comparative Examples 1-6 (Example 8 is a reference example)
100 parts by weight of the binder resin shown in Table 3, 4 parts by weight of carbon black “MOGUL-L” (Cabot) and 0.5 parts by weight of polyethylene wax “SP-105” (Sazol, melting point: 105 ° C.) After thorough mixing with a Henschel mixer, melt kneading using a co-rotating twin-screw extruder with a heating temperature in the roll of 100 ° C., cooling and coarsely crushing the resulting kneaded product, crushing with a jet mill, and classification As a result, a powder having a volume average particle size of 8.0 μm was obtained.
[0043]
By adding 0.1 part by weight of hydrophobic silica “TS-530” (Cabot Corp., average particle size: 8 nm) as an external additive to 100 parts by weight of the obtained powder, and mixing with a Henschel mixer, The body was surface treated to obtain a toner.
[0044]
Test Example 1 [Environmental resistance]
Toner is mounted on a non-magnetic one-component developing device "Page Presto N-4" (manufactured by Casio Computer Co., Ltd.) equipped with a stainless steel developing roll, and 500 images are printed in a high-temperature and high-humidity environment of 40 ° C and 90% Obtained. The image densities of the 50th and 500th images were measured using a transmission Macbeth densitometer “TR-927”, and the environmental resistance was evaluated according to the following evaluation criteria. The results are shown in Table 3.
[0045]
〔Evaluation criteria〕
500th image density / 50th image density value is
◎: 0.95 or more ○: 0.85 or more, less than 0.95 ×: less than 0.85
Test Example 2 [Durability]
A two-component developer obtained by mixing 3 parts by weight of toner and 97 parts by weight of a silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd.) having an average particle size of 90 μm is mounted on “Pretail 550” (manufactured by Ricoh) After continuously printing an image with a printing rate of 5% for 10 hours, the developer is taken out, and the toner is sucked using a sieve having an opening of 32 μm, leaving only the carrier. The carbon content of the remaining carrier is measured using a carbon analyzer “EMIA-110” (manufactured by HORIBA, Ltd.), and the difference from the carbon content of the carrier that has been measured before mixing with the toner is determined in advance. As evaluated. The results are shown in Table 3. That is, it can be determined that the greater the difference in the carbon amount, the more toner is attached to the carrier and the lower the durability of the toner.
[0047]
〔Evaluation criteria〕
The difference in carbon content of the carrier before and after continuous printing is ◎: 0.05 or less ○: 0.05-0.1
×: 0.1 or more
[Table 3]

[0049]
From the above results, it can be seen that all of the toners of the examples have good results in terms of pulverization, environmental resistance, and durability.
In contrast,
(1) In Comparative Example 1, since the acid value of the low grindability index resin is high, the environmental resistance is lowered.
(2) In Comparative Examples 2 and 4, since the grindability of the low grindability index resin and the high grindability index resin is close, the grinding surface during the production of the toner becomes unstable, and the environmental resistance decreases. There is also a decrease in durability due to the generation of fine powder,
(3) In Comparative Example 3, since the acid value of the high grindability index resin is adjusted by increasing the amount of the alcohol component, the durability is lowered due to a large amount of unreacted alcohol component remaining.
(4) In Comparative Example 5, since only the high pulverization index resin having a high acid value is contained as the binder resin, the environmental resistance is lowered.
{Circle around (5)} In Comparative Example 6, since only the low pulverizability index resin having a low acid value is contained as the binder resin, it can be seen that the durability is lowered.
[0050]
【The invention's effect】
According to the present invention, a toner excellent in environmental resistance and a binder resin for toner used in the toner can be provided without impairing pulverization and durability.

Claims (4)

A binder resin for toner comprising two types of resins having different grindability indexes of 5 to 17 , wherein the acid value of the resin having a lower grindability index (low grindability index resin) is 7.6 mgKOH / A binder resin for toner, in which the acid value of a resin having a higher pulverizability index (high pulverizability index resin) is 15 mgKOH / g or more.   2. The binder resin for toner according to claim 1, wherein the two resins having different grindability indexes are polyesters.   The binder resin for toner according to claim 1 or 2, wherein a weight ratio of the high pulverization index resin and the low pulverization index resin (high pulverization index resin / low pulverization index resin) is 60/40 to 98/2. Claim 1-3 toner containing the binder resin for toner and a colorant of any one.