JP2002053640A - Elastic member and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elastic member having excellent characteristics such as low hardness, micro cells, low residual strain of compression, high strength or the like. SOLUTION: This elastic member comprising polyurethane foam obtained by mixing a urethane prepolymer synthesized from a polyol and a polyisocyanate and water, uses (A) a polymer polyol synthesized by using a polyether polyol including >=70 wt.% of oxypropylene unit as a base, (B) a hydrophilic polyether polyol including >=50 wt.% of oxyethylene unit or jointly using (C) a polyether polyol including >=70 wt.% of oxypropylene unit to these, and an image forming device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic member used in an image forming apparatus such as an electrophotographic apparatus, an electrostatic recording apparatus, and a toner flying recording apparatus. The present invention relates to an elastic member having excellent characteristics such as residual strain and high strength, and an image forming apparatus equipped with the elastic member. The present invention also provides a puff material comprising a polyurethane foam forming the elastic member,
The present invention relates to cosmetic products such as sponges and scourers or bath products.

[0002]

2. Description of the Related Art In recent years, with the advance of electrophotographic technology, a medium resistance elastic roller has attracted attention as a transfer member, a toner supply member, a charging member and the like of a dry electrophotographic apparatus. Used for rollers, charging rollers, and the like. As a material for forming the medium resistance elastic roller, a polymer elastomer or a polymer foam having rubber elasticity has been used. Conventionally,
The members used for such purposes include NBR, E
There are elastomers and foams such as PDM, silicone rubber, and polyurethane, and members provided with conductivity by conductive carbon such as carbon black, metal oxides, ionic conductive agents, and the like are used as necessary. Among these, polyurethane materials can obtain low-hardness members suitable for the above members, and can be made into low-hardness foams by water, a method using a foaming agent such as a low-boiling compound, a method by mechanical stirring, or the like. , Are preferably used for the above members. The hardness of the polyurethane foam can also be reduced by selecting the raw materials that determine the chemical structure of the polyurethane and the amount of the raw materials that determine the chemical structure.

When a polyurethane foam is used as an elastic member for an image forming apparatus such as a toner supply roller,
It is required to have low hardness, low resistance, fine cells, low residual compression set, high tensile strength, and low cost. In such applications, the required electrical resistance of the elastic member varies depending on the type of toner (developer), the type of developing member, the power supply conditions, and the like. By adding or not adding, an elastic member having a low resistance to a high resistance is manufactured and used. Conventionally, as such an elastic member, an ester-based polyurethane foam from which relatively fine cells can be easily obtained by free foaming has been used. However, ester-based polyurethane foams have a problem that hydrolysis is likely to occur because they are ester-based. On the other hand, an ether-based polyurethane foam that does not hydrolyze tends to have large cells in free foaming, and requires pressure molding foaming to make the cells fine. In addition, the above-mentioned ester-based polyurethane foam is also used as a cosmetic product or a bath product, but the conventional ester-based polyurethane foam-made cosmetic puff material, bath scrubber, and the like are easily hydrolyzed, and therefore, in terms of durability. There is a problem and improvement is desired.

[0004]

SUMMARY OF THE INVENTION The present invention solves the problems of conventional elastic members, and comprises an elastic polyurethane foam having excellent properties such as low hardness, fine cells, low compression set, and high strength. It is an object of the present invention to provide a member, a cosmetic product and a bath product comprising the polyurethane foam.

[0005]

Means for Solving the Problems The present inventors have found that a polyurethane foam having fine cells is produced when a polyurethane foam is produced by stirring and mixing a urethane prepolymer synthesized from a polyol and a polyisocyanate with water and foaming with water. As a result of intensive studies on the method of producing a foam, the above-mentioned excellent properties were obtained by using a specific polymer polyol, a specific hydrophilic polyether polyol, and a polyether polyol having a large content of oxypropylene units in combination as a polyol. It has been found that an elastic member made of polyurethane foam having characteristics can be obtained. That is, when using a hydrophilic polyol alone, the cells of the polyurethane foam become fine, but since the hydrophilic polyol having a large number of polyoxyethylene chains has a high activity, the number of closed cells in the polyurethane foam increases, and when the foam is free-foamed, Normal polyurethane foam without shrinkage cannot be obtained. While maintaining the fine cells of the polyurethane foam when using the hydrophilic polyol, the present inventors,
After various investigations on a method for obtaining an appropriate polyurethane foam without shrinkage due to free foaming, it was found that by using a specific polymer polyol and a specific hydrophilic polyol in combination, uniform and fine cells were obtained, and closed cells were obtained. It has been found that a polyurethane foam which does not shrink can be obtained, and by further using a specific polyether polyol, a polyurethane foam having more excellent properties can be obtained. It has been found that it is suitable as a member to be mounted on a vehicle. In addition, they have found that such a polyurethane foam is suitable as a material for cosmetics and bath products. The present invention has been completed based on such findings.

That is, the present invention relates to an elastic member made of a polyurethane foam obtained by stirring and mixing a urethane prepolymer synthesized from a polyol and a polyisocyanate with water, wherein the polyol contains (A) oxypropylene units in an amount of 70% by weight. A combination of a polymer polyol synthesized based on the above-mentioned polyether polyol and (B) a hydrophilic polyether polyol containing 50% by weight or more of oxyethylene units, or (A)
A polymer polyol synthesized on the basis of a polyether polyol containing 70% by weight or more of oxypropylene units, (B) a hydrophilic polyether polyol containing 50% by weight or more of oxyethylene units, and (C) 70% by weight of oxypropylene units An object of the present invention is to provide an elastic member characterized by using the above-mentioned polyether polyol in combination, an image forming apparatus equipped with the elastic member, and a cosmetic product and a bath product comprising the above-mentioned ether-based polyurethane foam.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a polymer polyol (A) is a polymer polyol synthesized on the basis of a polyether polyol containing at least 70% by weight of oxypropylene units. For example, polymer particles obtained by polymerizing a monomer having an ethylenic double bond, preferably a monomer such as acrylonitrile or styrene, are dispersed in a polyether polyol. In the polymer polyol (A), the content of oxypropylene units is 7
It is preferably from 0 to 100% by weight, particularly preferably from 80 to 100% by weight. The polyether polyol is obtained by addition polymerization of propylene oxide and ethylene oxide to an initiator such as glycerin, trimethylolpropane, ethylene glycol, propylene glycol, pentaerythritol, and sorbitol.
The polymer polyol (A) has 2 to 6 functional groups, particularly
Those having a weight average molecular weight of from 2,000 to 4,000, particularly from 2,500 to 5,000 are preferably used. The polymer component (solid content) contained in the polymer polyol is preferably 15 to 45% by weight, particularly preferably 20 to 40% by weight. As a monomer constituting the polymer, for example, a monomer having an ethylenic double bond, specifically, acrylonitrile or styrene is preferably mentioned, and in addition, melamine and the like can be mentioned.
As the polymer component, an acrylonitrile homopolymer or a copolymer of acrylonitrile and styrene is preferable. The hydrophilic polyether polyol (B) is a hydrophilic polyether polyol containing 50% by weight or more of oxyethylene units, and includes glycerin, trimethylolpropane, ethylene glycol, propylene glycol,
It is obtained by adding propylene oxide and ethylene oxide to an initiator such as pentaerythritol and sorbitol. In the hydrophilic polyether polyol (B), the content of the oxyethylene unit is preferably 50% by weight or more. The hydrophilic polyether polyol (B) has a functional group number of 2 to 6, particularly 2.5 to 4, and a weight average molecular weight of 1500 to 6000, particularly 2500 to 5000.
Is preferably used. The polyether polyol (C) is a polyether polyol containing oxypropylene units in an amount of 70% by weight or more. Propylene oxide and ethylene oxide are used as initiators such as glycerin, trimethylolpropane, ethylene glycol, propylene glycol, pentaerythritol, and sorbitol. Is subjected to addition polymerization. In the polyether polyol (C), the content of oxypropylene units is 80
It is particularly preferable that the content be from 100 to 100% by weight. The polyether polyol (C) has a functional group number of 2 to 6, especially 2.5 to 5.
4, weight average molecular weight of 1500 to 6000, especially 250
Those having 0 to 5000 are preferably used.

By changing the mixing ratio of the above polymer polyol (A), hydrophilic polyether polyol (B) and polyether polyol (C), polyurethane foams having various hardnesses can be obtained. Polymer polyol (A) and hydrophilic polyether polyol (B)
The mixing ratio of the polyether polyol (C) and the polyether polyol (C) is preferably from 3 to 4 in terms of reducing the compression set of the polyurethane foam and reducing the dimensional change.
80% by weight, hydrophilic polyether polyol (B) 20
-60% by weight and polyether polyol (C) 0-6
It is preferably 0% by weight. If the amount of the polymer polyol (A) is too large, the hardness of the polyurethane foam becomes too high. On the other hand, if the blending amount of the polymer polyol (A) is too small, communication of the foam is not promoted, and the foam after foaming tends to shrink. If the amount of the hydrophilic polyether polyol (B) is too large, the compression set of the polyurethane foam increases,
In addition, dimensional changes due to environmental conditions increase. If the amount of the hydrophilic polyether polyol (B) is too small, the cells of the polyurethane foam become large, which is unsuitable for an elastic member requiring fine cells. If the amount of the polyether polyol (C) is too large, there is a disadvantage that the cell diameter of the polyurethane foam becomes large. In the present invention, the combination of the two components of the polymer polyol (A) and the hydrophilic polyether polyol (B) provides the desired hardness, number of cells, electric resistance, compression set,
When physical properties such as tensile strength can be obtained, it is not necessary to add the polyether polyol (C). In this case, it is particularly preferable that the polymer polyol (A) is 60 to 75% by weight and the hydrophilic polyether polyol (B) is 25 to 40% by weight. When the polymer polyol (A), the hydrophilic polyether polyol (B) and the polyether polyol (C) are used in combination, the polymer polyol (A) has a content of 30 to 75% by weight and the hydrophilic polyether polyol (B) has a content of 25 to 75%. It is particularly preferred that the content is 40% by weight and the polyether polyol (C) is 10 to 30% by weight. When the polyol (C) is used in combination, the desired hardness,
There is an advantage that it is easier to obtain physical properties such as the number of cells, electric resistance, residual compression strain, and tensile strength.

As the polyol used in the synthesis of the prepolymer according to the present invention, if necessary, polyether polyols, polyester polyols, polyisoprene polyols, polybutadiene polyols, hydrogenated polybutadiene polyols and the like other than the above three kinds of polyols may be used. Can be appropriately used in a range that does not hinder the effect of the above.
Examples of the polyether polyol include polytetramethylene glycol, polyethylene glycol, propanediol, butanediol, and the like. Examples of the polyester polyol include a condensation-based polyester polyol obtained by condensation of a dicarboxylic acid and a diol or a triol, a lactone-based polyester polyol obtained by ring-opening polymerization of a lactone based on a diol or a triol, and a lactone terminated with a lactone. And an ester-modified polyol modified with an ester.

The polyisocyanate used in the synthesis of the prepolymer according to the present invention includes tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (crude MDI), isophorone diisocyanate, hydrogenated diphenylmethane isocyanate as isocyanate components. Polyisocyanates having no unsaturated bond, such as naphthalate, hydrogenated tolylene diisocyanate, hexamethylene diisocyanate, and modified isocyanurates thereof;
Modified products such as carbodiimide modified products and glycol modified products are preferably used. Particularly preferred is TDI-80 in which the ratio of 2,4-tolylene diisocyanate to 2,6-tolylene diisocyanate is 80/20 by weight. The NCO group (isocyanate group) content of the prepolymer according to the present invention is preferably 3 to 30% by weight, particularly preferably 5 to 15% by weight.

NCO groups / O of urethane prepolymer and water
The chemical equivalent ratio of the H group is preferably from 1/100 to 1/2, and particularly preferably from 2/100 to 10/100. In the present invention, a foam stabilizer is added during the stirring and mixing of the urethane prepolymer and water to stabilize the cells of the polyurethane foam. As the foam stabilizer, a polyether-modified silicone foam stabilizer is preferred, and those containing 55% by weight or more, especially 60% by weight or more of oxyethylene units in the polyether portion are preferred. The amount of the silicone foam stabilizer is preferably 1 to 5 parts by weight, particularly preferably 2 to 3 parts by weight, based on 100 parts by weight of the urethane prepolymer.

Examples of the catalyst for curing the foam include monoamines such as triethylamine and dimethylcyclohexylamine, diamines such as tetramethylethylenediamine, tetramethylpropanediamine and tetramethylhexanediamine, pentamethyldiethylenetriamine and pentamethyldipropylene. Triamine,
Triamines such as tetramethylguanidine, cyclic amines such as triethylenediamine, dimethylpiperazine, methylethylpiperazine, methylmorpholine, dimethylaminoethylmorpholine, dimethylimidazole, dimethylaminoethanol, dimethylaminoethoxyethanol, trimethylaminoethylethanolamine, methyl Alcohol amines such as hydroxyethylpiperazine, hydroxyethylmorpholine, bis (dimethylaminoethyl) ether, ethylene glycol bis (dimethyl)
Ether amines such as aminopropyl ether, stannas octoate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin marker, dibutyltin thiocarboxylate, dibutyltin dimaleate, dioctyltin marker, dioctyltin thiocarboxylate, phenylmercurypropion And organometallic compounds such as lead octenoate. Of these, organotin catalysts are particularly preferred. These catalysts may be used alone or in combination of two or more. In the present invention, if necessary, other additives such as a flame retardant, a punching / cutting processability improving agent, an organic filler, and an inorganic filler can be added during the stirring and mixing.

The elastic member of the present invention can be formed into various shapes. When it is formed into a roller shape, the logarithmic value of the roller resistance (Ω) is 9.0 [log Ω] or more, particularly 10.
0 [logΩ] or more, and Asker F hardness of the roller is 40 to
85 degrees, especially 40 to 70 degrees, more preferably 45 to 65 degrees, the number of cells per 25 mm of the polyurethane foam is 50 to 2
00 pieces, especially 50-120 pieces, further 60-100 pieces,
Residual compression set is 1 to 10%, especially 1 to 5%, tensile strength is 0.1%.
Those having a pressure of 15 to 0.50 MPa are preferably used. The density of the polyurethane foam is 0.05 to 0.2 g / c.
m ³ is preferable, and 0.09 to 0.15 g / cm ³ is particularly preferable. Although the elastic member of the present invention can be used for various applications, it can be particularly suitably used as a developer supply member or a transfer member of an image forming apparatus. When these are formed in a roller shape, a form in which a polyurethane foam is formed around a metal shaft can be used. As the metal shaft, a steel shaft such as sulfur free-cutting steel plated with zinc or the like, or a shaft made of aluminum, stainless steel, phosphor bronze, or the like can be used. The ether-based polyurethane foam of fine cells according to the present invention is also preferably used as a cosmetic product such as a puff material or a bath product such as a scourer.

[0014]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, about the roller etc. obtained by the Example and the comparative example, the characteristic test was performed as follows. (1) Density The value was obtained by dividing the weight of the polyurethane foam in the air by the volume. (2) Number of cells Using a CCD video camera manufactured by Hilox Co., Ltd.
Photographs are taken at a magnification of 0 to 60 times, and the number of cells in the image is set to J.
It was measured in accordance with IS K6402. (3) Compression residual strain Measured according to JIS K 6382. (4) Tensile strength Measured according to JIS K6301. (5) Roller resistance A load of 100 g was applied to both ends of the roller to be tested and pressed against a copper plate, and a resistance value was measured by applying a voltage of 100 V using a resistivity meter R8340A (manufactured by Advantest).

Example 1 A weight average molecular weight of 5 obtained by adding 15% by weight of ethylene oxide and 85% by weight of propylene oxide to glycerin.
Solid content based on polyether polyol of 000 (acrylonitrile, styrene polymer)
20 weight parts of a polymer polyol of about 28 weight%, 75 weight% of ethylene oxide and 25 weight% of propylene oxide added to glycerin, weight average molecular weight 3400
40 parts by weight of a hydrophilic polyether polyol which is a glycerin and 15% by weight of ethylene oxide and 85% by weight of propylene oxide, and a weight average molecular weight of 480.
After weighing out 40 parts by weight of polyether polyol (0) and 21 parts by weight of tolylene diisocyanate (TDI-80) into a sealable container, closing the container lid and shaking the container to thoroughly mix the contents, C. in a hot-air circulation oven. Occasionally, the container was removed from the oven, shaken, and heated for 48 hours while mixing the contents. The NCO content of the prepolymer synthesized in this way was 6.0% by weight. Then, a dipropylene glycol solution of 70% by weight of bis- (dimethylaminoethyl) -ether was used as a catalyst in 100 parts by weight of this prepolymer and 22.5 parts by weight of water [Kaolyzer No. 12]
0.1 parts by weight and a mixture of 2.5 parts by weight of a reactive silicone foam stabilizer comprising 70% by weight of polyoxyethylene (25.1 parts by weight in total) were mixed with a high-speed mixer. The mixture is 300 mm x 150 mm x 50
mm into a free foaming box without lid, and after foaming, 100 ℃
For 15 minutes to produce a polyurethane foam. Using a vertical cutter, form
Cut out to a size of 8mm x 28mm x 240mm, 28
A 5.0 mm diameter hole was made in the center of the surface of a 28 mm × 28 mm surface perpendicular to this surface, and this hole was hot-melt sheet wrapped around the surface and zinc-coated with a diameter of 6.0 mm. A steel shaft was inserted and heated in a hot air circulating oven at 120 ° C. for 70 minutes to bond the polyurethane foam to the shaft. The polyurethane foam with the shaft was polished by a grinder, and the end of the polyurethane foam was further cut to produce a polyurethane foam roller having an outer diameter of 13.4 mm and a length of 217 mm (polyurethane foam portion). This roller has a polyurethane foam density of 0.102 g / cm ³ , 113 cells / 25 mm, residual compression set of 3.4%, tensile strength of 0.163 MPa, 20 ° C. and 50% RH. The resistance was 10 ^10.55 Ω, the Asker F hardness of the roller was 49 degrees, and the roller had suitable characteristics. This roller is incorporated in a dry electrophotographic apparatus as a toner supply roller, and is subjected to low temperature and low humidity conditions (15 ° C., 10%) and high temperature and high humidity conditions (32.
(5 ° C., 85%) for 48 hours.
When a solid white image and a solid black image were printed, good images were obtained.

Example 2 A weight average molecular weight of 5 obtained by adding 15% by weight of ethylene oxide and 85% by weight of propylene oxide to glycerin.
Solid content based on polyether polyol of 000 (acrylonitrile, styrene polymer)
40 weight parts of a polymer polyol of about 28 weight%, 75 weight% of ethylene oxide and 25 weight% of propylene oxide added to glycerin, and a weight average molecular weight of 3400
60 parts by weight of a hydrophilic polyether polyol and 21 parts by weight of tolylene diisocyanate (TDI-80) are weighed into a sealable container, the container is closed, and the container is shaken to thoroughly mix the contents. It was placed in a hot air circulating oven at 60 ° C. Occasionally, the container was removed from the oven, shaken, and heated for 48 hours while mixing the contents. The NCO content of the prepolymer synthesized in this way is 6.
It was 0% by weight. Then, a dipropylene glycol solution of 70% by weight of bis- (dimethylaminoethyl) -ether was used as a catalyst in 100 parts by weight of this prepolymer and 22.5 parts by weight of water [Kaolyzer No. 1
2] A high-speed mixer is used to mix a mixture of 0.1 part by weight and 2.5 parts by weight of a reactive silicone foam stabilizer comprising polyoxyethylene in which 70% by weight of the ether chain is dissolved (total 25.1 parts by weight). And the mixture is 300 mm x 150 mm x
Pour into a 50mm free foam box without lid and after foaming 10
The composition was cured at 0 ° C. for 15 minutes to produce a polyurethane foam. This foam was processed in the same manner as in Example 1 to produce a polyurethane foam roller having an outer diameter of 13.4 mm and a length of 217 mm (polyurethane foam portion). The density of the polyurethane foam part of this roller is 0.0
77 g / cm ³ , 115 cells / 25 mm, residual compression set 6.2%, tensile strength 0.175 MPa, 20 ° C.
The roller resistance at 50% RH was 10 ^11.04 Ω, and the Asker F hardness of the roller was 34 degrees, which was favorable. This roller is incorporated in a dry electrophotographic apparatus as a toner supply roller, and is subjected to low temperature and low humidity conditions (15 ° C., 10 ° C.).
%) And high-temperature and high-humidity conditions (32.5 ° C., 85%) for 48 hours, respectively, and then a solid white image and a solid black image were printed. As a result, good images were obtained.

Example 3 Using the same mixture as in Example 1, a polyurethane foam was produced by a pressure molding method. That is, as a pressure mold, a rubber packing is used at a portion where the upper mold and the lower mold are rubbed, there is no vent hole, and the inner dimension is 50 mm.
The above mixture was injected into this pressure mold by using an aluminum thing of 50 mm × 50 mm × 300 mm.
The composition was cured at 0 ° C. for 15 minutes to produce a polyurethane foam. This foam was processed in the same manner as in Example 1 to produce a polyurethane foam roller having an outer diameter of 13.4 mm and a length of 217 mm (polyurethane foam portion). The density of the polyurethane foam part of this roller is 1.3
3 g / cm ³ , number of cells is 158/25 mm, residual compression set is 8.3%, tensile strength is 0.196 MPa, 20 ° C., 5
The roller resistance at 0% RH was 10 ^10.40 Ω, the Asker F hardness of the roller was 72 degrees, and the roller had suitable characteristics. This roller is incorporated in a dry electrophotographic apparatus as a toner supply roller, and is used under low-temperature and low-humidity conditions (15 ° C., 10%)
After standing for 48 hours under high-temperature and high-humidity conditions (32.5 ° C., 85%), a solid white image and a solid black image were printed, and good images were obtained. Example 4 Using the same mixture as in Example 2, a polyurethane foam was produced by a pressure molding method in the same manner as in Example 3. This foam was processed in the same manner as in Example 1 and had an outer diameter of 1
A polyurethane foam roller having a length of 3.4 mm and a length of 217 mm (polyurethane foam portion) was produced. The density of the polyurethane foam part of this roller is 1.11 g / c.
m ³ , the number of cells is 186/25 mm, and the compression set is 8.9.
%, Tensile strength 0.207MPa, 20 ° C, 50% RH
The roller resistance was 10 ^10.88 Ω, and the Asker F hardness of the roller was 60 degrees, and the roller had suitable characteristics.
This roller was incorporated in a dry electrophotographic apparatus as a toner supply roller, and left for 48 hours under low-temperature and low-humidity conditions (15 ° C., 10%) and high-temperature, high-humidity conditions (32.5 ° C., 85%). When a solid black image was printed, a good image was obtained.

Comparative Example 1 Glycerin was added with 15% by weight of ethylene oxide and 85% by weight of propylene oxide.
After weighing 100 parts by weight of polyether polyol 800 and 22.2 parts by weight of tolylene diisocyanate (TDI-80) in a sealable container, closing the container lid, shaking the container and thoroughly mixing the contents. And placed in a hot air circulation oven at 60 ° C. Occasionally, the container was removed from the oven, shaken, and heated for 48 hours while mixing the contents. The NCO content of the prepolymer synthesized in this way was 6.1% by weight. Next, this prepolymer 10
A 70% by weight dipropylene glycol solution of bis- (dimethylaminoethyl) -ether as a catalyst in 0 parts by weight and 22.5 parts by weight of water [Kaolyser N manufactured by Kao Corporation]
o. 12] 0.1 parts by weight and a mixture of 2.5 parts by weight of a silicone foam stabilizer composed of polyoxyethylene in which 50% by weight of an ether chain is dissolved (25.1 parts by weight in total) are mixed by a high-speed mixer, The mixture is 300mm x 300mm x
Inject into a 70mm free foam box without lid and after foaming 10
The composition was cured at 0 ° C. for 15 minutes to produce a polyurethane foam. This foam was processed in the same manner as in Example 1 to produce a polyurethane foam roller having an outer diameter of 13.4 mm and a length of 217 mm (polyurethane foam portion). The density of the polyurethane foam part of this roller is 0.0
91 g / cm ³ , number of cells is 79/25 mm, residual compression set is 6.9%, tensile strength is 0.161 MPa, 20 ° C., 5
The roller resistance at 0% RH was 10 ^11.76 Ω, the Asker F hardness of the roller was 55 degrees, the compression residual strain was small and good, but the cell was large. This roller is incorporated into a dry electrophotographic apparatus as a toner supply roller, and is subjected to low temperature and low humidity conditions (15 ° C., 10%) and high temperature and high humidity conditions (32.5
(C, 85%) for 48 hours, and then, when a solid white image and a solid black image were printed, image irregularities considered to be caused by coarse cells occurred under any of the conditions.

Comparative Example 2 Glycerin was added with 75% by weight of ethylene oxide and 25% by weight of propylene oxide.
100 parts by weight of a hydrophilic polyether polyol of 400 and tolylene diisocyanate (TDI-80) 23
Weigh the weight in a sealable container, close the lid of the container,
After shaking the container to thoroughly mix the contents, the container was placed in a 60 ° C. hot air circulation oven. Occasionally, the container was removed from the oven, shaken, and heated for 48 hours while mixing the contents. The NCO content of the prepolymer synthesized in this way was 5.9% by weight. Next, this prepolymer 1
A 70% by weight solution of bis- (dimethylaminoethyl) -ether in dipropylene glycol as a catalyst in 00 parts by weight and 22.5 parts by weight of water [Kaolyser N manufactured by Kao Corporation]
o. 12] 2.5 parts by weight of a reactive silicone foam stabilizer comprising 0.1 parts by weight and 70% by weight of ether chains of polyoxyethylene
Parts by weight of the mixture (25.1 parts by weight in total) were mixed with a high-speed mixer, and the mixture was 300 mm × 150 mm.
It was poured into a free foaming box having a size of 50 mm x 50 mm without a lid, and after foaming, cured at 100 ° C for 15 minutes to produce a polyurethane foam. This foam has strong closed cells,
It shrank and deformed as it cooled. We also tried foam crushing to prevent this shrinkage, but we could not perform crushing because the closed cells were strong, and when the foam was further compressed, the foam punctured, and a normal polyurethane foam that can be used for rollers was I couldn't get it.

Comparative Example 3 Glycerin was added with 75% by weight of ethylene oxide and 25% by weight of propylene oxide.
60 parts by weight of a hydrophilic polyether polyol of 400, 40 parts by weight of a polyether polyol having a weight average molecular weight of 4800 obtained by adding 15% by weight of ethylene oxide and 85% by weight of propylene oxide to glycerin, and tolylene diisocyanate (TDI-80) 23 parts by weight were weighed out in a sealable container, the lid of the container was closed, the container was shaken to sufficiently mix the contents, and then placed in a 60 ° C. hot air circulation oven. Occasionally, the container was removed from the oven, shaken, and heated for 48 hours while mixing the contents. The NCO content of the prepolymer synthesized in this way was 6.0% by weight. Next, this prepolymer 10
A 70% by weight dipropylene glycol solution of bis- (dimethylaminoethyl) -ether as a catalyst in 0 parts by weight and 22.5 parts by weight of water [Kaolyser N manufactured by Kao Corporation]
o. 12] 2.5 parts by weight of a reactive silicone foam stabilizer comprising 0.1 parts by weight and 70% by weight of ether chains of polyoxyethylene
Parts by weight of the mixture (25.1 parts by weight in total) were mixed with a high-speed mixer, and the mixture was 300 mm × 150 mm.
It was poured into a free foaming box having a size of 50 mm x 50 mm without a lid, and after foaming, cured at 100 ° C for 15 minutes to produce a polyurethane foam. This foam has strong closed cells,
It shrank and deformed as it cooled. We also tried foam crushing to prevent this shrinkage, but the closed cells were so strong that crushing could not be performed, and when the foam was further compressed, the foam punctured and a normal polyurethane foam that could be used for rollers was used. I couldn't get it.

Comparative Example 4 Glycerin was added with 15% by weight of ethylene oxide and 85% by weight of propylene oxide.
Solid content based on polyether polyol of 000 (acrylonitrile, styrene polymer)
About 28% by weight of a polymer polyol 60 parts by weight, glycerin added with 15% by weight of ethylene oxide and 85% by weight of propylene oxide, and has a weight average molecular weight of 4800.
Weighing 40 parts by weight of polyether polyol and 19 parts by weight of tolylene diisocyanate (TDI-80) in a sealable container, closing the lid of the container, shaking the container and thoroughly mixing the contents, and then heating at 60 ° C. In a hot air circulation oven. Occasionally, the container was removed from the oven, shaken, and heated for 48 hours while mixing the contents. The NCO content of the prepolymer synthesized in this way was 6.1% by weight. Next, 100 parts by weight of the prepolymer,
A solution of bis- (dimethylaminoethyl) -ether in 70% by weight of dipropylene glycol as a catalyst in 22.5 parts by weight of water [Kaolyzer No. 12] 0.1
Parts by weight and a mixture (2.5 parts by weight in total) in which 2.5 parts by weight of a reactive silicone foam stabilizer comprising polyoxyethylene in which 70% by weight of the ether chain is composed of polyoxyethylene are mixed by a high-speed mixer, and the mixture is mixed. 300mm x 150mm x 50mm
Into a free foam box without a lid, and after foaming,
It was cured for 5 minutes to produce a polyurethane foam. This foam was processed in the same manner as in Example 1 and had an outer diameter of 1
A polyurethane foam roller having a length of 3.4 mm and a length of 217 mm (polyurethane foam portion) was produced. The density of the polyurethane foam part of this roller is 0.118 g /
cm ³ , the number of cells is 56/25 mm, and the compressive residual strain is 6.4
%, Tensile strength 0.151MPa, 20 ° C, 50% RH
The roller resistance was 10 ^11.02 Ω, the Asker F hardness of the roller was 87 degrees, the cells were larger than the target polyurethane foam, and the hardness was higher. This roller was incorporated in a dry electrophotographic apparatus as a toner supply roller, and left for 48 hours under low-temperature and low-humidity conditions (15 ° C., 10%) and high-temperature, high-humidity conditions (32.5 ° C., 85%). When a solid black image was printed, image irregularities considered to be caused by the coarse cells occurred under any conditions.

[0022]

The elastic member of the present invention has excellent characteristics such as low hardness, fine cells, low compression set and high strength, and the polyurethane foam forming the elastic member can be produced by free foaming. Things. The elastic member of the present invention is suitable as a member for an image forming apparatus such as a developer supply roller and a transfer roller, and a cosmetic or bath product made of this polyurethane foam has excellent durability.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // (C08G 18/48 (C08G 18/48 F 101: 00) 101: 00) F-term (Reference) 2H032 AA05 2H077 AC04 FA22 3J103 AA02 FA12 GA02 GA52 GA54 GA57 GA58 HA03 HA20 HA48 4J034 BA07 DA01 DF01 DG03 DG04 DG09 DG14 DP12 DQ05 DQ16 DQ18 GA06 GA33 HA01 HA07 HC03 HC12 HC17 HC22 HC46 HC52 HC64 HC67 HC71 NA73 KB73

Claims (9)

[Claims] An elastic member comprising a polyurethane foam obtained by stirring and mixing a urethane prepolymer synthesized from a polyol and a polyisocyanate and water,
As the polyol, (A) an oxypropylene unit of 70
A polymer polyol synthesized based on a polyether polyol containing not less than 50% by weight and (B) a hydrophilic polyether polyol containing not less than 50% by weight of oxyethylene units, or (A) 70% by weight of oxypropylene units; A polymer polyol synthesized on the basis of the above-mentioned polyether polyol, (B) a hydrophilic polyether polyol containing 50% by weight or more of oxyethylene units, and (C) 70% of oxypropylene units
An elastic member characterized in that it is used in combination with a polyether polyol containing not less than% by weight. 2. The polyether polyol (C) wherein the oxypropylene unit in the polymer polyol (A) is 75 to 100% by weight, and the oxyethylene unit in the hydrophilic polyether polyol (B) is 60 to 100% by weight. The oxypropylene unit in is 75 to 10
The elastic member according to claim 1, which is 0% by weight. 3. The mixing ratio of the polymer polyol (A), the hydrophilic polyether polyol (B) and the polyether polyol (C) is from 3 to 3 of the polymer polyol (A).
80% by weight, hydrophilic polyether polyol (B) 20
-60% by weight and polyether polyol (C) 0-6
3. The elastic member according to claim 1, wherein the amount is 0% by weight. 4. The elastic member according to claim 1, wherein the stirring and mixing of the urethane prepolymer and water are performed by further adding a catalyst and a foam stabilizer. 5. The elastic member according to claim 4, wherein the foam stabilizer is a polyether-modified silicone foam stabilizer, and the polyether portion of the foam stabilizer contains 60% by weight or more of oxyethylene units. 6. The elastic member has a roller shape, and the roller has an electric resistance of a logarithmic value [logΩ].
9.0 or more, Asker F hardness is 40 to 85 degrees, and the number of cells per 25 mm of the polyurethane foam is 50 to 200.
Pieces, compression residual strain is 1-10%, and tensile strength is 0.15-0.1.
The elastic member according to claim 1, wherein the elastic member has a pressure of 50 MPa. 7. The elastic member according to claim 1, wherein the elastic member is a developer supply roller or a transfer roller for an image forming apparatus. 8. An image forming apparatus comprising the elastic member according to claim 1. 9. A cosmetic or bath product comprising the polyurethane foam according to claim 1.