JPH09118733A - Production of urethane elastomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a urethane elastomer excellent in molding surface precision by performing molding and curing by using a specified urethane prepolymer and a curing agent comprising an amine-type polyol or a mixture of a polyol and/or a polyhydric alcohol. SOLUTION: An aromatic polyisocyanate such as 4,4'-diphenylmethane diisocyanate is reacted with a polyol (e.g. polyoxyalkylene polyol) having an active hydrogen equivalent of about 500-5,000, and a functionality of about 2-3 to prepare a urethane prepolymer of an isocyanate equivalent of 200-1,000. Next, this prepolymer is mixed with a curing agent comprising a tert.-amino- containing amine or a mixture comprising an amine-type polyol and a polyol and/or a polyhydric alcohol in amounts to give an equivalent ratio of the active hydrogens of the curing agent to the isocyanato groups of the prepolymer of about 1.20-0.75. The resultant mixture is poured into e.g. a centrifugal molding machine and molded and cured at 100-170 deg.C to obtain a urethane elastomer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a urethane elastomer whose molding surface is mirror-like and has good surface accuracy.

[0002]

2. Description of the Related Art As a method for producing a urethane elastomer, for example, a urethane prepolymer composed of polyester polyol and diphenylmethane diisocyanate is used as a main component and a curing agent composed of 1,4-butanediol and trimethylolpropane is used for centrifugal molding. Is known (for example, JP-A-63-8685).

[0003]

However, in the conventional method, when the molding is performed by centrifugal molding or single-sided open mold casting, the molding surface becomes uneven, and the surface accuracy is low. Therefore, for example, it is pressed against a photoreceptor such as an electrophotographic copying machine. When it is used for a cleaning blade used for cleaning fine particle toner, there is a problem that cleaning property is insufficient.

[0004]

Means for Solving the Problems In the method of manufacturing by centrifugal molding or single-sided open mold casting, the present inventors have
The present invention has been achieved as a result of extensive studies on a method for producing a urethane elastomer having a good molding surface accuracy. That is, the present invention is characterized in that, when a urethane elastomer is produced by centrifugal molding or single-sided open mold casting, it is cured at a temperature of 100 to 170 ° C. by using the following main component and curing agent, and the molding surface accuracy is good. A method for producing a urethane elastomer having a main component: an isocyanate group equivalent derived from a polyol (a) and an aromatic polyisocyanate (b) is 200.
To 1,000 urethane prepolymer (A) Curing agent: amine-based polyol (d) alone or (d)
And a polyol (a) and / or a polyhydric alcohol (c) (the equivalent ratio of the amine-based polyol in the curing agent is 3 to 100%), and an electrophotographic photograph of a urethane elastomer obtained by the production method. The present invention relates to a cleaning blade for a copying machine.

Examples of the polyol (a) constituting the urethane prepolymer (A) as the main component in the present invention include polyoxyalkylene polyol (a), polyester polyol (b), polyolefin polyol (c),
Acrylic polyols (d), castor oil-based polyols (e), and mixtures of two or more thereof.

Examples of the polyoxyalkylene polyol (a) include active hydrogen-containing compounds [polyhydric alcohols {aliphatic dihydric alcohols (ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, neopentyl Glycol, 1,6-hexanediol, 1,8-octamethylenediol, etc.), low molecular weight diols having a cyclic group [1,4-bis (hydroxymethyl) cyclohexane,
m- and p-xylylene glycol, 1,4-bis (2-hydroxyethoxy) benzene, 1,4-bis (α-hydroxyisopropyl) benzene, 2,2-bis (4-hydroxyethoxyphenyl) propane, etc.] Trihydric alcohols (glycerin, trimethylolpropane, hexanetriol, etc.), tetrahydric or higher polyhydric alcohols (sorbitol, sucrose, etc.), phenols (hydroquinone, bisphenol A, etc.)], and alkylene oxide (2 carbon atoms
To alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide and a combination of two or more of these) are added (in the case of combined use, block or random addition is possible). Specific examples of the polyoxyalkylene polyol (a) include polyoxypropylene glycol, polyoxypropylene triol, polyoxyethylene polyoxypropylene glycol, polyoxyethylene polyoxypropylene triol, polyoxypropylene tetraol, and polyoxytetramethylene. Examples include glycol.

As the polyester polyol (b),
Condensed polyester polyols obtained by reacting the above-exemplified polyhydric alcohols or polyoxyalkylene polyols (a) with dicarboxylic acids, polylactone polyols obtained by ring-opening polymerization of lactones, ethylene carbonate and 1,6-hexane Polycarbonate polyols obtained by reaction with diols are included.

Examples of the dicarboxylic acids constituting the condensed polyester polyol include aliphatic dicarboxylic acids (succinic acid, adipic acid, sebacic acid, glutaric acid, azelaic acid, maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (terephthalic acid). Acid, isophthalic acid, etc.); anhydrides of these dicarboxylic acids, lower alkyls (C1-C1)
4) ester or halide (such as chloride); and a mixture of two or more kinds thereof. Examples of lactones include ε-caprolactone.

Specific examples of the polyester polyol (b) include polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polyneopentyl adipate, polyethylene propylene adipate,
Polyethylene butylene adipate, polybutylene hexamethylene adipate, polydiethylene adipate, poly (polytetramethylene ether) adipate, polyethylene azelate, polyethylene sebacate, polybutylene azelate, polybutylene sebacate, polyethylene terephthalate, polycaprolactone diol , Polycaprolactone triol, polycarbonate diol and the like.

Specific examples of the polyolefin polyol (c) include polybutadiene polyol, hydrogenated polybutadiene polyol and polyisoprene polyol.

As the acrylic polyol (d), a hydroxyl group-containing ethylenically unsaturated monomer [2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, etc.] and other than that, for example, JP-A No. 4/1999 can be used. Examples thereof include copolymers with an ethylenically unsaturated monomer described in JP-A-292683. Specific examples of the acrylic polyol (d) include a copolymer of hydroxyethyl acrylate and ethyl acrylate, a copolymer of hydroxyethyl acrylate, ethyl acrylate and styrene, and the like.

Examples of castor oil-based polyols (e) include castor oil, polyester polyols of castor oil fatty acid and the above polyhydric alcohols and polyoxyalkylene polyols (castor oil fatty acid mono- or diglyceride, castor oil fatty acid and Mono-, di- or triesters from trimethylolpropane, mono- or diesters from castor oil fatty acids and polyoxypropylene glycols, castor oils with addition of alkylene oxides and mixtures of two or more thereof. Can be given.

Among the above-mentioned polyols (a), preferred are (a), (b) and (c).

The active hydrogen equivalent of the polyol (a) is usually 300 to 10,000, preferably 500 to 5,000.
0. The number of functional groups is usually 2 to 4, preferably 2 to 3.
It is.

Specific examples of the aromatic polyisocyanate (b) include 1,4-phenylene diisocyanate, toluene diisocyanate (TDI), diphenylmethane-2,4'- or 4,4'-diisocyanate (MDI), naphthalene-. 1,5-diisocyanate,
3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, o-tolidine diisocyanate, crude T
DI, polyphenylmethane polyisocyanate (crude M
DI), modified products thereof (carbodiimide group, uretidione group, uretoimine group, urea group, buret group,
Modified products having isocyanurate groups, urethane groups, etc. introduced therein and mixtures of two or more thereof.

The isocyanate group equivalent of the urethane prepolymer (A) used in the present invention is usually 200 to 1.0.
00, preferably 200 to 850. If the isocyanate group equivalent is less than 200, the surface accuracy of the molded product will be insufficient, and if it exceeds 1,000, the viscosity of the prepolymer will increase and centrifugal molding will be difficult.

As the curing agent in the present invention, a combination of a polyhydric alcohol (c) and an amine polyol (d), a combination of the polyol (a), a polyhydric alcohol (c) and an amine polyol (d). , A combination of the polyol (a) and the amine-based polyol (d), an amine-based polyol (d) alone, and the like. The equivalent ratio of the amine-based polyol (d) in the curing agent is usually 3 to 1.
It is 00%, preferably 5 to 100%. If it is less than 3%, the surface accuracy is insufficient. By using the amine-based polyol (d) as an essential component, it is possible to obtain a high-strength urethane elastomer having no unevenness and excellent surface accuracy. Although the mechanism of action is not clear, the movements of the amine-based polyol (d) that cause unevenness due to curing shrinkage or the like immediately before gelation in the process leading to curing because the reaction rates of the respective components are too different.
It is presumed that the high reactivity and the catalytic action of sucrose have been balanced.

As the above amine-based polyol (d),
Alkanolamines (triethanolamine, N-methyldiethanolamine, diethanolamine, triisopropanolamine, ethanolamine, etc.), amine compounds (ethylenediamine, tetramethylenediamine,
Hexamethylenediamine, n-butylamine, stearylamine, aniline, diethylaminoethylamine, diethylenetriamine, etc.) and compounds obtained by adding alkylene oxide to alkanolamine.
Among these, preferred are amine-based polyols having a tertiary amino group in the molecule.

The polyhydric alcohol (c) includes at least one polyhydric alcohol exemplified as the starting material for the polyoxyalkylene polyol (a).

The above-mentioned urethane prepolymer (A) can be produced by a one-shot method or a multi-step method in which predetermined amounts of the polyol (a) and the aromatic polyisocyanate (b) are added, if necessary, in the presence of a known urethanization catalyst. Known methods can be mentioned. Examples of the method for producing the above-mentioned curing agent include a method in which the polyhydric alcohol (c) and the amine-based polyol (d) are mixed and dehydrated if necessary.

When the urethane elastomer is produced by the method of the present invention, the equivalent ratio of the active hydrogen group of the curing agent to the isocyanate group of the main agent is usually 1.2 to 0.75.

The method for producing the urethane elastomer of the present invention is as follows:
It is a method of using a centrifugal molding machine or a method of casting in a single-sided open mold. When using a centrifugal molding machine,
After mixing the main agent and the curing agent, the mixture is poured into a centrifugal molding machine and usually cured at a temperature of 100 to 170 ° C. and a rotation speed of 300 to 1500 rotations / minute to produce a urethane elastomer. When casting in a single-sided open mold, after mixing the main agent and the curing agent, pour into the mold, usually at a temperature of 100
Cure at ~ 170 ° C. In any of the above cases, the preferable range of the curing temperature is 120 to 160. Curing temperature is 10
If the temperature is lower than 0 ° C., especially in the case of urethane prepolymer of polyester polyol, the elastomer crystallizes and becomes cloudy, and an elastomer having satisfactory surface accuracy and physical properties cannot be obtained. On the other hand, if the temperature exceeds 170 ° C, the elastomer deteriorates.

The urethane elastomer produced by the method of the present invention may optionally contain known additives such as flame retardants, fillers, plasticizers and antiaging agents. Flame retardants include metal hydroxides (aluminum hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, strontium hydroxide, etc.), metal carbonates (magnesium carbonate, calcium carbonate, nickel carbonate, strontium carbonate, barium carbonate). Etc.), halogen-containing phosphate ester-based flame retardants [trischloroethylphosphate, trisdichloropropylphosphate, trischloropropylphosphate, tris (tribromophenyl) phosphate, trisdibromopropylphosphate, tris (dibromophenylphenyl) Phosphate, tris (tribromoneopentyl) phosphate, etc.], active hydrogen-containing flame retardant [di (isopropyl) N, N
-Bis (2-hydroxyethyl) aminomethyl phosphate, alkylene oxide adduct of brominated bisphenol A, etc.], brominated bisphenol A, urea, urea derivative (reaction product of urea and formalin), thiourea,
Examples include melamine, melamine derivatives (reaction products of melamine and formalin, etc.), antimony trioxide, antimony pentoxide, zinc oxide, zinc borate and the like. These are 2
You may use it in combination of 2 or more types. Examples of the filler include talc, mica, carbon black, titanium oxide, fine powder silica, straight asphalt, cutback asphalt and the like. Examples of the plasticizer include dioctyl phthalate, dibutyl phthalate, dioctyl adipate, dioctyl sebacate, chlorinated paraffin, petroleum resin and the like. As an anti-aging agent, a hindered amine type [4-benzoyloxy-2,2,6,6-tetramethylpiperidine (“SANOL LS-74 manufactured by Sankyo”) is used.
4 ")], hindered phenols [octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (Nippon Ciba Geigy" Irganox 1076 "), etc.], benzophenone (2- Hydroxy-4-methoxybenzophenone, etc.), benzotriazole-based [2- (5-methyl-2-hydroxyphenyl) benzotriazole, etc.] and the like.

The urethane elastomer obtained by the method of the present invention has surface smoothness, water resistance, mechanical strength, flexibility,
It is suitable for automobile members, electric product members, OA equipment members, building members and the like, which are required to have weather resistance, heat resistance, wear resistance and the like. Above all, it is particularly useful as a cleaning blade for an electrophotographic copying machine which requires surface accuracy.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be further described below with reference to examples, but the present invention is not limited to these examples. In the following, parts are parts by weight,% is% by weight, and ratios are weight ratios. The meanings of the abbreviations in the examples and the evaluation test methods are as follows. (Abbreviation) PBA: polybutylene adipate [molecular weight = 2000,
Product name = Sanester 4620, Sanyo Chemical Industry Co., Ltd.] PEA: Polyethylene adipate [Molecular weight = 2000,
Product name = San Ester 2620, manufactured by Sanyo Chemical Industry Co., Ltd.] MDI: 4,4′-diphenylmethane diisocyanate BD: 1,4-butanediol TMP: trimethylolpropane TE: triethanolamine TI: triisopropanolamine

(Evaluation Test Method) 1. Surface accuracy: Surface roughness meter [LT made by KEYENCE CORPORATION, LT
-8010] (unit = μm). 2. Hardness: Measured with A type of JIS K6301. 3. Tensile properties: Measured according to JIS K6301 (1
(00% stress and tensile strength; unit = Kg / cm ² , elongation rate; unit =%, tear strength; unit = Kg / cm).

[0027]

【Example】

[Production of Main Agent] Production Example 1 PBA716g and MDI284g in 4-necked Kolben
Was charged, and reacted at 90 ° C. for 5 hours in a nitrogen gas atmosphere,
The main agent <1> of the present invention having an isocyanate group equivalent of 646 was obtained.

Production Example 2 PEA (478 g) and MDI (522 g) in a 4-neck Kolben
Was charged, and reacted at 90 ° C. for 5 hours in a nitrogen gas atmosphere,
A main agent <2> of the present invention having an isocyanate group equivalent of 271 was obtained.

[Production of Curing Agent] Production Examples 3 to 7 The components shown in Table 1 were charged in a 4-necked Kolben and the mixture was heated to 70 ° C.
The mixture was stirred and mixed for 30 minutes to obtain the curing agents [1] to [5] of the present invention.

[0030]

[Table 1]

Examples 1 to 5 The main agent of which the temperature ratio was 80 ° C. and the temperature was 40 ° C.
The temperature-controlled curing agent was weighed in a container, mixed with a screw-bladed stirrer, and degassed in vacuum. The liquid was poured into a centrifugal molding machine whose temperature was adjusted to 150 ° C., and molded at 1000 rpm.
After 60 minutes, it was demolded and then after-cured at 100 ° C. for 10 hours to obtain a urethane elastomer. Table 2 shows the surface precision, hardness and tensile property test results for each of these elastomers.

[0032]

[Table 2]

Examples 6 to 7 The main agent of which the temperature ratio is 80 ° C. and the temperature ratio of 40 ° C. are shown in Table 3.
The temperature-controlled curing agent was weighed in a container, mixed with a screw-bladed stirrer, and degassed in vacuum. The liquid was poured into a single-sided open mold whose temperature was adjusted to 150 ° C. to mold. After 60 minutes, it was demolded and then after-cured at 100 ° C. for 10 hours to obtain a urethane elastomer. Table 3 shows the test results of surface accuracy, hardness and tensile properties of each of these elastomers.

COMPARATIVE EXAMPLE 1 The main agent adjusted to a temperature of 80 ° C. and the temperature of 40 ° C. in the part ratio shown in Table 4 were used.
The temperature-controlled curing agent (BD and TMP were mixed in advance in the part ratio shown in Table 4) was weighed in a container and screwed.
The mixture was mixed with a stirrer with wings and degassed in vacuum. 150 ℃ the liquid
It was poured into a centrifugal molding machine whose temperature was adjusted to 1000 and molded at 1000 rpm. After 60 minutes, it was demolded and then after-cured at 100 ° C. for 10 hours to obtain a urethane elastomer. Table 4 shows the test results of surface accuracy, hardness and tensile properties of this elastomer.

COMPARATIVE EXAMPLE 2 The main agent adjusted to a temperature of 80 ° C. and the temperature of 40 ° C. in the part ratio shown in Table 4 were used.
The temperature-controlled curing agent (BD and TMP were mixed in advance in the part ratio shown in Table 4) was weighed in a container and screwed.
The mixture was mixed with a stirrer with wings and degassed in vacuum. 150 ℃ the liquid
It was molded by pouring into a single-sided open mold whose temperature was adjusted to.
After 60 minutes, it was demolded and then after-cured at 100 ° C. for 10 hours to obtain a urethane elastomer. Table 4 shows the test results of surface accuracy, hardness and tensile properties of this elastomer.

As is clear from Table 2, Table 3 and Table 4, the urethane elastomer obtained by the production method of the present invention is
Especially the surface accuracy is excellent.

[0037]

EFFECT OF THE INVENTION By using the method of the present invention, it is possible to produce a urethane elastomer having extremely high surface accuracy. Further, the obtained elastomer is excellent in abrasion resistance, mechanical properties, water resistance, heat resistance, flexibility and the like. Due to the above effects, the elastomer obtained by the method for producing a urethane elastomer of the present invention is suitable for use in cleaning blades for OA equipment (electrophotographic copying machines, etc.), squeegees for printing, belts, glass run members for automobiles, etc. Especially useful for.

[Table 3]

[Table 4]

Claims (3)

[Claims] 1. When manufacturing a urethane elastomer by centrifugal molding or single-sided open mold casting, the following main component and a curing agent are used to cure at a temperature of 100 to 170 ° C., and the molding surface precision is good. Method for producing flexible urethane elastomer. Main agent: An isocyanate group equivalent derived from the polyol (a) and the aromatic polyisocyanate (b) is 200.
To 1,000 urethane prepolymer (A) Curing agent: amine-based polyol (d) alone or (d)
And a polyol (a) and / or a polyhydric alcohol (c) (the equivalent ratio of the amine-based polyol in the curing agent is 3 to 100%). 2. The production method according to claim 1, wherein the amine-based polyol (d) is a polyol having a tertiary amino group in the molecule. 3. A cleaning blade for an electrophotographic copying machine, comprising a urethane elastomer obtained by using the manufacturing method according to claim 1.