JP2003140520A - Urethane composition for cleaning blade and cleaning blade obtained using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a urethane composition for a cleaning blade excellent in curability, wear and chipping resistances. SOLUTION: The urethane composition for a cleaning blade comprises the following components (A)-(D) as essential components and has an NCO index of >=115; (A) a polyol, (B) a polyisocyanate, (C) an organic acid and (D) a catalyst comprising at least one of 1,8-diazabicyclo (5,4,0)-undecene-7 and 1,5- diazabicyclo(4,3,0)-nonene-5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning blade urethane composition for removing toner remaining on the outer peripheral surface of a photosensitive drum of an electrophotographic copying machine and the like, and a cleaning blade using the same.

[0002]

2. Description of the Related Art In an electrophotographic copying machine, an outer peripheral surface of a photosensitive drum is uniformly charged, and then the outer peripheral surface is exposed through a copied image of a copying object, so that an electrostatic latent image is formed on the outer peripheral surface. Generally, an image is formed, and a charged toner is attached to the electrostatic latent image to form a toner image, and the toner image is transferred to a copy paper or the like to perform copying. In such an electrophotographic copying machine, after the toner image is transferred, the toner remains on the outer peripheral surface of the photosensitive drum. Therefore, a cleaning blade can be slid on the outer peripheral surface of the photosensitive drum to scrape off and remove the residual toner. It is being appreciated.

As the above-mentioned cleaning blade, a polyurethane composition having excellent mechanical properties such as abrasion resistance has been conventionally praised. For example, a polyurethane obtained by reaction curing in the presence of a diazabicycloamine salt. A cleaning blade made of an elastic material has been proposed (Japanese Patent Laid-Open No. 9-212059).

[0004]

However, in the cleaning blade described in JP-A-9-212059, since the catalyst is a salt, the reaction rate becomes slow and the balance between pot life and curability becomes poor. There's a problem. Further, since the NCO index is low, when used for a long period of time, there is a problem that the edge portion of the cleaning blade that is in sliding contact with the photosensitive drum is worn or chipped.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a urethane composition for a cleaning blade having excellent curability, wear resistance and chipping resistance, and a cleaning blade using the same. And

[0006]

In order to achieve the above object, the present invention comprises the following (A) to (D) as essential components,
The first gist is a urethane composition for a cleaning blade having an NCO index of 115 or more. (A) Polyol. (B) Polyisocyanate. (C) Organic acid. (D) 1,8-diazabicyclo (5,4,0) -undecene-7 and 1,5-diazabicyclo (4,3,0)
-A catalyst comprising at least one of Nonene-5.

A second aspect of the present invention is a cleaning blade comprising the urethane composition for a cleaning blade.

That is, the inventors of the present invention have conducted extensive studies in order to obtain a urethane composition for cleaning blades which is excellent in curability, abrasion resistance and chipping resistance. as a result,
The NCO index is set higher than before to increase abrasion resistance and chipping resistance by increasing nurate cross-linking, and the reaction is accelerated by using a specific catalyst and the reaction is blocked by using an organic acid. The inventors have found that the intended purpose can be achieved by adjusting the speed appropriately, and have reached the present invention.

When polybutylene adipate (PBA) is used as the above-mentioned polyol, abrasion resistance and chipping resistance are further improved.

Further, when triethylenediamine (catalyst) is used in combination with the above-mentioned specific catalyst (D component), the hydrolysis resistance becomes better, and the quaternary ammonium salt (catalyst) is obtained.
If used together, the workability becomes better.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described.

The cleaning blade urethane composition of the present invention comprises a polyol (component A), a polyisocyanate (component B), an organic acid (component C) and a specific catalyst (component D).
And are essential ingredients.

The polyol (component A) is not particularly limited, and examples thereof include polyester polyols such as polyester diol and polyester triol, and polyether polyols such as polycaprolactone, polycarbonate, polyoxytetramethylene glycol and polyoxypropylene glycol. Can be given. These may be used alone or in combination of two or more.

As the polyester polyol, a hydroxyl polyester polyol having a hydroxyl group as an end group, which is produced from a polybasic organic acid and a polyol, is preferably used. The polybasic organic acid is not particularly limited, and examples thereof include saturated fatty acids such as oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and isosebacic acid.
Unsaturated fatty acids such as maleic acid and fumaric acid, dicarboxylic acids such as aromatic acids such as phthalic acid, isophthalic acid, terephthalic acid, acid anhydrides such as maleic anhydride and phthalic anhydride, dialkyl esters such as dimethyl terephthalate, Examples thereof include dimer acid obtained by dimerization of unsaturated fatty acids. The above-mentioned polyol is not particularly limited, and examples thereof include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butylene glycol,
Examples thereof include diols such as neopentyl glycol and 1,6-hexylene glycol, trimethylolethane, trimethylolpropane, hexanetriol, triols such as glycerin, and hexaols such as sorbitol.

As the above polyether polyol, those produced by ring-opening polymerization or copolymerization of cyclic ether are preferably used. Examples of the cyclic ether include ethylene oxide, propylene oxide, trimethylene oxide, butylene oxide,
Examples include α-methyltrimethylene oxide, 3,3′-dimethyltrimethylene oxide, tetrahydrofuran, dioxane and dioxamine.

In the present invention, as the above-mentioned polyol (component A), polybutylene adipate (PBA) is preferably used among the above series because of its excellent abrasion resistance and chipping resistance.

The number average molecular weight (Mn) of the polyol (component A) is preferably in the range of 1000 to 3000, and particularly preferably 1500 to 2600. That is, when the Mn of the polyol (component A) is less than 1000, the physical properties of the cleaning blade to be obtained tend to deteriorate, and conversely when Mn exceeds 3000, workability tends to deteriorate. Is.

The polyisocyanate (component B) used together with the polyol (component A) is not particularly limited, and examples thereof include 4,4'-diphenylmethane diisocyanate (MDI) and 2,4-tolylene diisocyanate (2,4). -TDI), 2,6-tolylene diisocyanate (2,6-TDI), 3,3'-vitrylene-4,
4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, 2,4-tolylene diisocyanate uretidinedione (2,4-TD
I dimer), 1,5-naphthylene diisocyanate,
Metaphenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4 '
-Dicyclohexyl methane diisocyanate (hydrogenated MD
I), carbodiimide-modified MDI, orthotoluidine diisocyanate, xylene diisocyanate, paraphenylene diisocyanate, lysine diisocyanate methyl ester, triphenylmethane-4,4 ', 4 "-triisocyanate, polymeric MDI, etc. These may be used alone or Two or more of these are used in combination, and among these, MDI is preferably used from the viewpoint of wear resistance.

The amount of the polyisocyanate (component B) to be blended must be set so that the NCO index (isocyanate index) is 115 or more, and it is particularly preferable to set the NCO index to be in the range of 115 to 130. . That is, if the NCO index is less than 115, wear resistance and chipping resistance are poor.

The NCO index is the total equivalent weight of raw material components having a hydroxyl group that reacts with an isocyanate group, 1
Mean equivalent of isocyanate to 00.

The organic acid (C component) used together with the above A component and B component is not particularly limited, and examples thereof include formic acid, acetic acid, propionic acid, valeric acid, caproic acid,
2-ethylhexanoic acid, cyanoacetic acid, pyruvic acid, benzoic acid, capric acid, stearic acid, butyric acid, monocarboxylic acids such as malic acid, adipic acid, azelaic acid, sebacic acid, isophthalic acid, terephthalic acid, oxydiacetic acid, Fumaric acid, oxalic acid, maleic acid, speric acid, pimelic acid, glutaric acid, malonic acid, phthalic anhydride, succinic anhydride, succinic acid, 1,11-undecadicarboxylic acid, 1,12-dodecanedicarboxylic Acid, undecadioic acid, decanedicarboxylic acid, dicarboxylic acid such as hexadecanedioic acid, salicylic acid, m-oxybenzoic acid, p-oxybenzoic acid, oxyphenylacetic acid,
Protocatechuic acid, gentisic acid, α-resorcinic acid,
β-resorcinic acid, γ-resorcinic acid, orseric acid,
Examples thereof include phenolic acids (phenolic carboxylic acids) such as caffeic acid, umbellic acid, gallic acid, and 3-oxyphthalic acid, phenol, and citric acid. These may be used alone or in combination of two or more. Among these, formic acid, acetic acid, and phenol are preferably used in terms of pot life and reactivity.

The content of the organic acid (component C) is preferably 0.00001 to 0.02% by weight, and particularly preferably 0.0001 to 0.02% by weight, based on the total weight of the urethane composition. That is, when the content of the organic acid (component C) is less than 0.00001% by weight, the reaction rate is fast and casting becomes difficult, while when it exceeds 0.02% by weight, the reaction is slow and the curability becomes poor. Because it is inferior.

The specific catalyst (component D) used with the above components A to C is 1,8-diazabicyclo (5,4,4).
0) -undecene-7 (DBU) and 1,5-diazabicyclo (4,3,0) -nonene-5 (DBN).

The content of the specific catalyst (component D) is preferably 0.0001 to 0.1% by weight, and particularly preferably 0.005 to 0.05% by weight, based on the total weight of the urethane composition. That is, when the content of the specific catalyst (D component) is less than 0.0001% by weight, the composition is not sufficiently cured and it takes time to mold, and conversely, when it exceeds 0.1% by weight, the curing is quick. It is because it is too hard and hardens when stirred.

In the present invention, other catalysts may be used in combination with the above-mentioned specific catalyst (component D), for example, amine compounds such as tertiary amines, quaternary ammonium salts, organotin compounds. And the like. Examples of the tertiary amine include trialkylamines such as triethylamine, tetraalkyldiamines such as N, N, N ′, N′-tetramethyl-1,3-butanediamine, amino alcohols such as dimethylethanolamine, and the like. Ethoxylated amine, ethoxylated diamine,
Esteramines such as bis (diethylethanolamine) adipate, triethylenediamine (TEDA), N,
Cyclohexylamine derivatives such as N-dimethylcyclohexylamine, N-methylmorpholine, morpholine derivatives such as N- (2-hydroxypropyl) -dimethylmorpholine, N, N'-diethyl-2-methylpiperazine,
Examples thereof include piperazine derivatives such as N, N'-bis- (2-hydroxypropyl) -2-methylpiperazine.
The quaternary ammonium salt may be, for example, 2
-Hydroxypropyl trimethyl ammonium octylate (DABCO TMR, manufactured by Sankyo Air Products), 2-hydroxypropyl trimethyl ammonium ammonium formate (DABCO TMR-2, manufactured by Sankyo Air Products), and the like. Examples of the organic tin compound include dialkyltin compounds such as dibutyltin dilaurate and dibutyltin di (2-ethylhexoate), stannous 2-ethylcaproate, stannous oleate, and the like. To be These may be used alone or in combination of two or more. Among these catalysts, triethylenediamine (TEDA) is preferably used in terms of hydrolysis resistance, and a quaternary ammonium salt is preferably used in terms of processability.

The content of the other catalyst such as triethylenediamine is 0.0005 to 0.0 based on the total weight of the urethane composition.
A range of 3% by weight is preferable, and 0.001 is particularly preferable.
~ 0.01 wt%.

When the above-mentioned specific catalyst (component D) is used in combination with another catalyst, the mixing ratio by weight of both is preferably D component / other catalyst = 10/1 to 1/10.

The urethane composition used in the present invention contains, in addition to the components A to D, a chain extender, a foaming agent, a surfactant, a flame retardant, a colorant, a filler, a plasticizer, a stabilizer, and a release agent. A mold agent or the like may be contained.

Examples of the chain extender include 1,4-
Butanediol (1,4-BD), ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, xylene glycol, triethylene glycol, trimethylolpropane (TMP), glycerin,
Polyols having a molecular weight of 300 or less such as pentaerythritol, sorbitol, 1,2,6-hexanetriol, 2,2 ', 3,3'-tetrachloro-4,4'-diaminodiphenylmethane (TCDMA), 3,3'-Dichloro-4,4'-diphenylmethane, trimethylene-
Examples thereof include aromatic diamines such as bis (4-aminobenzoate) and 4,4′-diamino-3,3′-diethyl-5,5′-dimethyldiphenylmethane. These may be used alone or in combination of two or more.

A cleaning blade using the urethane composition of the present invention comprises, for example, as shown in FIG. 1, the urethane composition cured body 1 supported by a plate-shaped holder 2.

The cleaning blade of the present invention can be manufactured using the above-mentioned materials according to a conventional method. Specifically, it can be produced according to a prepolymer method, a semi-one-shot method, or a one-shot method. Among them, the semi-one-shot method is preferably used from the viewpoint of excellent workability.

According to the semi-one-shot method, the cleaning blade of the present invention is manufactured, for example, as follows. That is, first, the above polyol (component A)
And polyisocyanate (component B) are prepared, both are mixed in an appropriate mixing ratio, and reacted under appropriate reaction conditions to prepare a urethane prepolymer. Then, an organic acid (C component) is blended with the urethane prepolymer to prepare a base material liquid composed of the urethane prepolymer and the organic acid (C component). On the other hand, the above-mentioned polyol (component A) and, if necessary, a chain extender and the like are prepared, these are blended in an appropriate blending ratio, and mixed under appropriate mixing conditions to prepare a curing agent liquid. Next, in the presence of the above-mentioned specific catalyst (component D) and other catalysts, the above-mentioned main agent liquid and curing agent liquid are added to the specified NC.
The mixture is mixed and mixed at an appropriate mixing ratio so as to obtain the O index, and the mixed liquid is injected into the cleaning blade molding die holding the plate-shaped holder 2 to be reactively cured. Then, the obtained cured product is taken out of the mold and processed into a predetermined shape. In this way, the cleaning blade integrally formed with the plate-shaped holder 2 as shown in FIG. 1 can be obtained.

The organic acid (component C) may be blended in the curing agent liquid. Further, the specific catalyst (D component) and other catalysts may be blended in the curing agent liquid. In this case, it is preferable that the specific catalyst (D component) is blended on the side of a liquid different from the liquid in which the organic acid (C component) is blended.

Further, the cleaning blade of the present invention is
It is not always necessary to integrally mold the plate-shaped holder 2, and for example, it may be manufactured by a post-bonding method in which the plate-shaped holder 2 is bonded to the surface later.

The hardness (JIS A) of the cured product is 80.
The angle is preferably less than or equal to 0 °, particularly preferably in the range of 70 to 80 °. That is, when the hardness exceeds 80 °, it tends to be too hard and the cleaning property tends to be poor.

Next, examples will be described together with comparative examples.

First, prior to Examples and Comparative Examples, the following materials were prepared.

[Polyol] PBA (manufactured by Nippon Polyurethane Industry Co., Ltd., N4010, Mn: 2000, OH value: 5)
6.1 KOHmg / g)

[Polyol] Polycaprolactone (PC
L) (Placcel 220, M, manufactured by Daicel Chemical Industries, Ltd.
n: 2000, OH value: 56.1 KOHmg / g)

[Low molecular weight polyol] 1,4-BD and T
Mixture of MP (mixing molar ratio: 1,4-BD / TMP = 6
0/40)

[0041]

Examples 1 to 6 and Comparative Examples 1 to 4 First, urethane compositions prepared by mixing the components shown in Tables 1 and 2 below in the proportions shown in the same table were prepared.

Next, the urethane compositions of Examples and Comparative Examples were used to evaluate each characteristic according to the following criteria. The results are also shown in Tables 1 and 2 below.

[Pot life] A main agent liquid (liquid temperature 70) comprising a prepolymer and an organic acid (comparative example is not blended)
C.) and a curing agent liquid (liquid temperature 70.degree. C.) were prepared. Then, in the presence of a catalyst, both liquids were mixed so as to have a predetermined NCO index, stirred for 30 seconds with a stirring blade while defoaming in vacuum, and then the liquid temperature was raised to 140 ° C, and the viscosity of the liquid was measured with a B-type viscometer. Was measured using. As an evaluation criterion, the pot life time from the start of mixing until the viscosity reached 1,000 mPa · s was measured, and when the pot life time was 1 minute and 50 seconds or more, it was evaluated as ○, and when it was less than 1 minute and 50 seconds, it was evaluated as ×. .

[Curing] The viscosity is 10 after pot life.
The curing time until it reached 10,000 mPa · s was measured. The evaluation criteria for curability were as follows: those with a curing time of 3 minutes and 30 seconds or less were evaluated as ○, and those with a curing time exceeding 3 minutes and 30 seconds were evaluated as ×.

[Hardness] First, a cleaning blade molding die in which a plate-shaped holder is arranged is prepared, and each of the urethane compositions is injected into the die and allowed to react at 140 ° C. for 30 minutes for curing to obtain a cured product. Got After that, the mold was removed, and a desired cleaning blade was produced by forming it into a predetermined shape using a knife. Then, the hardness (JIS A) of the cured product was measured.

[Chiping Resistance] Each cleaning blade was incorporated into a commercially available laser printer, and 30,000 sheets of A3 size were printed under a high temperature and high humidity environment (35 ° C. × 85% RH). Then, the presence or absence of chipping of the edge portion of the cleaning blade after the image formation of 30,000 sheets was observed with a scanning electron microscope at a magnification of 500 times. The evaluation criteria were ◯ when there was no chipping, and x when there was a chipping and there was a practical problem.

[Abrasion resistance] Each cleaning blade was incorporated into a commercially available laser printer, and 30,000 sheets of A3 size were printed in a high temperature and high humidity environment (35 ° C. × 85% RH), and then a scanning type electronic The amount of wear at the edge of the cleaning blade was observed with a microscope. Then, the cross-sectional area (U μm ² ) of the worn portion and the unit length (Xμ
m), and the wear amount (Wμ
m ³ ) was calculated. As the evaluation criteria, the case where the amount of wear was less than 50 μm ³ was ◯, and the case where the wear amount was 50 μm ³ or more was x.

[0048]

[Table 1]

[0049]

[Table 2]

From the above results, it can be seen that the products of Examples all have a good pot life and are excellent in curability, chipping resistance and abrasion resistance.

On the other hand, in Comparative Example 1, the catalyst is TE
It can be seen that since only DA is used, the curability and wear resistance are poor. Further, it is understood that Comparative Examples 2 to 4 products are inferior in curability, chipping resistance and abrasion resistance because the catalyst is a DBU salt.

[0052]

As described above, the urethane composition for cleaning blades of the present invention improves abrasion resistance and chipping resistance by setting the NCO index higher than before and increasing nurate crosslinking, and , The reaction is accelerated by using a specific catalyst and the reaction is blocked by using an organic acid to optimize the reaction rate. As a result, the urethane composition for cleaning blades of the present invention has a good pot life and excellent curability, and the cleaning blade of the present invention using the same has excellent wear resistance and chipping resistance.

Further, when polybutylene adipate (PBA) is used as the polyol (component A), the abrasion resistance and chipping resistance are further improved.

Furthermore, when triethylenediamine (catalyst) is used in combination with the above-mentioned specific catalyst (D component), the hydrolysis resistance becomes better, and the quaternary ammonium salt (catalyst) is obtained.
If used together, the workability becomes better.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing an example of a cleaning blade of the present invention.

[Simple explanation of symbols]

1 Urethane composition cured product 2 Plate-shaped holder

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Suzuki             Tokai Rubber Works, Higashi 3-chome, Komaki City, Aichi Prefecture             Business (72) Inventor Akihiro Maeda             Tokai Rubber Works, Higashi 3-chome, Komaki City, Aichi Prefecture             Business (72) Inventor Hiroyuki Mori             Tokai Rubber Works, Higashi 3-chome, Komaki City, Aichi Prefecture             Business (72) Inventor Fumio Misumi             Tokai Rubber Works, Higashi 3-chome, Komaki City, Aichi Prefecture             Business F term (reference) 2H134 GA01 GB02 HD04 HD19 KD08                       KD11 KH15                 4F071 AA53 AC12 AE03 AF14 AF22                       AH16 BA09 BB01 BB12 BC03                 4J034 BA08 CA02 CA03 CA04 CA05                       CA15 CA22 CA24 CA25 CB01                       CB02 CB03 CB04 CB05 CB07                       CC03 CC12 CD13 DA01 DB04                       DB05 DB07 DF01 DF02 DF12                       DF16 DF20 DF22 DG02 DG03                       DG04 DG05 DG06 HA01 HA02                       HA06 HA07 HA08 HB12 HC03                       HC12 HC13 HC17 HC22 HC34                       HC46 HC52 HC61 HC64 HC65                       HC67 HC71 HC73 JA01 KA01                       KB02 KC17 KD12 KE02 QA03                       QB15 QC08 QD03 RA14

Claims (5)

[Claims] 1. The following (A) to (D) as essential components,
A urethane composition for a cleaning blade having an NCO index of 115 or more. (A) Polyol. (B) Polyisocyanate. (C) Organic acid. (D) 1,8-diazabicyclo (5,4,0) -undecene-7 and 1,5-diazabicyclo (4,3,0)
-A catalyst comprising at least one of Nonene-5. 2. The urethane composition for a cleaning blade according to claim 1, wherein the polyol (A) is polybutylene adipate. 3. The urethane composition for a cleaning blade according to claim 1, which contains triethylenediamine. 4. The urethane composition for a cleaning blade according to claim 1, which contains a quaternary ammonium salt. 5. A cleaning blade comprising the urethane composition for a cleaning blade according to claim 1.