JP2001294642A - Polyurethane elastomer-based actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyurethane elastomer-based actuator having excellent electrostriction characteristics. SOLUTION: The polyurethane elastomer-based actuator is produced from a polyisocyanate and at least one kind of polyol selected from a polyol having amide group and a polyol containing a polymer having amide group. The water content of the polyurethane elastomer-based actuator is 0.01-50 wt.% and the actuator has a property to amplify the strain caused by the orientation of the polyurethane elastomer in the direction of electric field applied to the elastomer in a water-containing state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane elastomer actuator. More specifically, the present invention relates to a polyurethane elastomer-based actuator utilizing orientation characteristics by applying an electric field.

[0002]

2. Description of the Related Art Conventionally, lead zirconate titanate (PZT)
2. Related Art Piezoelectric ceramics and piezoelectric polymers such as polyvinylidene fluoride (PVDF) are known as piezoelectric materials. These materials are recognized for their performance as acoustic materials, and have already been put to practical use in applications such as speakers and headphones. However, these piezoelectric materials are not suitable as actuators driven at low voltage. This is because these materials have a disadvantage that the amount of electrostriction does not increase unless the applied voltage is considerably increased.

On the other hand, polyurethane elastomers have also been reported in many researches as actuator materials and new piezoelectric materials (for example, Seiji Asai et al., Journal of Polymers, No. 56).
Vol. 2, No. 67-76, 1999), and patent applications. JP-A-6-85339 discloses a polyurethane elastomer having a dielectric polyol or a polyol having a substituent having a relatively strong dipole moment, wherein the polyol is subjected to an electric field by applying a DC electric field to the polyurethane elastomer. A directionally oriented polyurethane elastomer actuator is disclosed.

As the polyol used in the invention according to the above publication, polyester polyols, polyether polyols, polycarbonate polyols, polybutadiene polyols and the like are described. Examples of the polyether polyol include polypropylene glycol, polyethylene glycol, a copolymer of propylene oxide and ethylene oxide, polytetramethylene ether glycol, and a copolymer of tetrahydrofuran and propylene oxide or ethylene oxide.

However, although the polyurethane elastomer materials using polyols used in these systems can be driven even at a relatively low applied voltage, the electrostriction constant expressing the electrostriction characteristics is at a considerably low level from the practical level. It is.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyurethane elastomer actuator which can be driven even at a relatively low applied voltage and has excellent electrostrictive characteristics.

[0007]

Means for Solving the Problems As a result of diligent studies to solve the above-mentioned problems, polyurethane elastomers were obtained by using a polyol having an amide group, a polyol containing a polymer having an amide group, or a mixture thereof as the polyol. The present inventors have found that the above-mentioned problems can be solved by preparing and adding a specific amount of water to the polyurethane elastomer, and arrived at the present invention.

According to the present invention, there is provided a polyurethane elastomer-based actuator produced from at least one polyol selected from a polyol having an amide group and a polyol containing a polymer having an amide group, and a polyisocyanate. A polyurethane elastomer-based actuator having a water content of 0.01 to 50% by weight and having a characteristic of amplifying a strain based on the orientation of the polyurethane elastomer in an electric field direction by application of an electric field in the water-containing state. Is done.

In the polyurethane elastomer actuator according to the present invention, the content of the amide group unit in at least one kind of polyol selected from a polyol containing an amide group and a polyol containing a polymer having an amide group is 3 to 60% by weight. It is preferred that The electrostriction constant, which is a main characteristic of the polyurethane elastomer-based actuator according to the present invention, is 5 × 10 ^{−17 to} 100 ×.
It is preferably in the range of 10 ⁻¹⁷ m ² / V ² .

In the present invention, the strain and the electrostriction constant are as follows:
This is a value calculated by the method described in the examples described later.

When an electric field is applied to the polyurethane elastomer-based actuator of the present invention, a change in the polymer conformation of the polyurethane elastomer occurs due to the orientation of the relatively strong dipole moment of the polyurethane elastomer itself. In particular, in the present invention, a high concentration of polar amide groups can be introduced by an amide group of the polyol or a polymer having an amide group dispersed in the polyol. A distortion characteristic is exhibited. for that reason,
In a state where the effective current is substantially extremely small, it may be possible to change the shape of the polyurethane elastomer only by the force of molecular orientation. In addition, the energy required for the deformation generated at the time of this shape change can be used as actuation.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. As described above, the function of the polyurethane elastomer material of the present invention as an actuator is based on the change in the polymer conformation of the polyurethane elastomer itself. For this reason, it has a feature that the response speed to the application of the voltage is extremely fast.

The polyurethane elastomer of the present invention can be obtained by the following method. That is, a polyol containing an amide group-containing polyol or a polymer containing an amide group-containing polymer, and an organic polyisocyanate, and a chain extender, if necessary, are reacted by a conventionally known method to produce a polyurethane elastomer-based actuator. . For example, a method comprising reacting a polyol containing an amide group or a polyol containing a polymer having an amide group with an organic polyisocyanate to obtain a urethane prepolymer and, if necessary, reacting a chain extender, or There is a so-called one-shot method in which reactions are simultaneously performed at a predetermined ratio. When a polyurethane elastomer is produced from an polyol having an amide group or a polyol containing a polymer having an amide group and an organic polyisocyanate, the molar ratio of NCO / OH is 0.5-2.
Is preferable. It is more preferably in the range of 0.6 to 1.5, and still more preferably in the range of 0.8 to 1.3.

As the polyisocyanate, 2
As long as it has at least two isocyanate groups,
For example, 4,4′-diphenylmethane diisocyanate,
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate,
Polymethylene polyfernyl polyisocyanate, norbornane diisocyanate, isophorone diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 4,4′-methylenebis ( Cyclohexyl isocyanate), p-phenylene diisocyanate, 1,5-
Naphthalene diisocyanate, 1,3-xylylene diisocyanate, α, α, α ′, α′-tetramethyl-1,3
-Xylylene diisocyanate, and modified isocyanurate, carbodiimidated, and buret modified products of these polyisocyanates. These may be used alone or in combination of two or more.

In the present invention, a polyol containing an amide group having strong polarity is used as the polyol. The amide group unit content in the polyol is preferably from 3 to 60% by weight from the viewpoint of amplifying the strain based on the orientation of the polyurethane elastomer in the electric field direction by applying an electric field. More preferably 6 to 40% by weight, even more preferably 9 to 30% by weight.
% By weight. In the present invention, as the polyol, a polyol having an amide group, a polyol containing a polymer having an amide group, or a mixture thereof can be used.

The polyol having an amide group used in the present invention is obtained, for example, by condensation of an amino alcohol or an amine having two or more amino groups in the molecule with an acid having two or more carboxyl groups in the molecule. Amide polyols, amino alcohols or half esters obtained by adding an amine having two or more amino groups in the molecule to an acid anhydride or alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, etc. Amide polyols obtained by the addition of

Examples of the amino alcohol include monoethanolamine, diethanolamine, N- (2-aminoethyl) ethanolamine, 2-hydroxyaniline,
Hydroxyaniline, 3- (2-hydroxyethylaminopropylamine) and the like. Examples of the amine having two or more amino groups in the molecule include ethylenediamine,
Triethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 3,
3′-iminobis (propylamine), 3- (methylamino) propylamine, N-methyl-3,3′-iminobis (propylamine), tolylenediamine, 4,4 ′
-Diaminodiphenylmethane, norbornanediamine,
Examples include isophoronediamine and polyetheramine obtained by converting a terminal hydroxyl group of a polyether polyol to an amino group. Examples of the acid having two or more carboxylic acids in the molecule include terephthalic acid, isophthalic acid, succinic acid, itaconic acid, adipic acid, azelaic acid, sebacic acid, dodecane diacid, and paraoxybenzoic acid. Examples of the acid anhydride include phthalic anhydride, maleic anhydride, succinic anhydride, trimellitic anhydride and the like. These may be used alone or in combination of two or more from the exemplified groups.

Further, a polyol containing a polymer having an amide group can also be used. That is, it is a so-called polymer-dispersed polyol in which polymer fine particles containing an amide group are dispersed in a polyol. Examples of the polymer having an amide group include polyacrylamides, aromatic polyamide, and nylon. Among these amide polyols, a polymer-dispersed polyol in which a polymer containing an amide group is dispersed in a polyol is preferred.

The polymer-dispersed polyol preferably used in the present invention will be described below. There are two methods for producing a polymer-dispersed polyol. (1) A method in which a polymer having an amide group is polymerized in a polyol to disperse polymer fine particles, and (2) A polymer particle obtained by polymerizing a monomer having an amide group in a solvent other than the polyol is dispersed in the polyol. It is a way to make it. In the method (2), the polymer particles in the solvent may be added to the polyol and then the solvent may be distilled off, or the dried polymer particles may be dispersed in the polyol. The dispersed amide group-containing polymer fine particles are at least one selected from amide group-containing vinyl polymers such as polyacrylamides and condensation polymers such as nylon. Preferably, it is a vinyl polymer containing an amide group.

The vinyl polymer containing an amide group is a vinyl polymer obtained by polymerizing a vinyl monomer containing a vinyl monomer having one or more amide groups in a molecule. Vinyl monomers having one or more amide groups in the molecule include acrylamide, N, N-dimethylacrylamide, N, N-dimethylaminomethylacrylamide, N, N-dimethylaminopropylacrylamide,
N-isopropylacrylamide, N-methylolacrylamide, N, N-dimethylolacrylamide,
N, N-diethylacrylamide, diacetoneacrylamide, acryloylmorpholine, acryloyl-L-
Glutamic acid dimethyl ester, acryloyl-L-proline methyl ester, acryloylpyrrolidine, 1,
Acrylamides such as 4-diacryloylpiperazine, N, N-dioctylacryloylamide, methylenebisacrylamide; methacrylamide, N, N-dimethylmethacryloylamide, 1-methacryloylimidazole, methacryloyl-L-valine methyl ester, methacryloyl-L- At least one of methacrylamides such as leucine methyl ester can be used.

The vinyl polymer containing an amide group may be a copolymer with a vinyl monomer other than a vinyl monomer having one or more amide groups in the molecule. Vinyl monomers other than the vinyl monomer having an amide group in the molecule include acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, 2-methylstyrene, 3
-Methylstyrene, 4-methylstyrene, 2-vinylphenol, 3-vinylphenol, 4-vinylphenol, p-isopropenylphenol, 3-vinylbenzoic acid, 4-vinylbenzoic acid, 4
-Vinylthiophenol, 4-methoxystyrene, 4-
Ethoxystyrene, 4-vinylbiphenyl, sodium p-styrenesulfonate, potassium p-styrenesulfonate, 4-aminostyrene, 5-aminostyrene, 4-
Dimethylaminostyrene, 4-vinylbenzyl alcohol, 4-phenoxystyrene, 4-vinylbenzoate, 4-acetoxystyrene, vinylphenylacetonitrile, 4-t-butylstyrene, p-octylstyrene, p-cyclohexylstyrene, p-dodecylstyrene , 4-isopropylstyrene, N- (4-vinylphenyl) maleimide, aromatic vinyl monomers such as divinylbenzene, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) Acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate,
Lauryl (meth) acrylate, stearyl (meth) acrylate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl crotonate, vinyl n-hexanoate, n-
Vinyl octanoate, vinyl n-decanoate, vinyl laurate, vinyl palmitate, vinyl stearate, N,
N-dimethylaminoethyl (meth) acrylate, 3-
Dimethylaminoneopentyl (meth) acrylate, 3
-(Dimethylamino) propyl (meth) acrylate,
Glycidyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and the like can be mentioned. Preferably, acrylonitrile and styrene are used.

Examples of the polyol in which the vinyl polymer containing an amide group is dispersed include polyoxyalkylene polyols, polyester polyols, polyether ester polyols which are usually used as raw materials for polyurethane.
Polyols such as polycarbonate polyols and polybutadiene polyols can be used.

Examples of the polyether polyol include monools such as methanol, butanol and allyl alcohol, water, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol and 1,6-hexanediol. Diols such as neopentyl glycol, glycerin, hexanetriol, trimethylolpropane, pentaerythritol, sorbitol, polyols such as sucrose, bisphenol A, bisphenol F, dihydroxybiphenyl, hydroquinone, resorcinol,
Aromatic compounds such as phloroglucin, naphthalene diol, aminophenol, aminonaphthol, phenol formaldehyde condensate, methyldiethanolamine, ethyldiisopropanolamine, monoethanolamine, diethanolamine, triethanolamine, ethylenediamine, hexamethylenediamine, diethylenetriamine, bis (p -Aminocyclohexyl) methane,
An initiator is a compound arbitrarily selected from the group consisting of aniline, toluidine, tolylenediamine, diphenylmethanediamine, naphthalenediamine and the like, and usually a catalyst such as an alkali metal compound and at least one of amines or a complex metal cyanide complex. Using ethylene oxide,
Polyoxyalkylene polyols obtained by adding epoxides such as propylene oxide, butylene oxide and styrene oxide, and polytetramethylene ether glycol obtained by polymerizing tetrahydrofuran in the presence of an acidic catalyst such as a boron trifluoride etherate complex Is mentioned.

Tetrahydrofuran includes copolymers with other alkylene oxides, specifically, copolymers of tetrahydrofuran and propylene oxide, copolymers of tetrahydrofuran and ethylene oxide (all of which have a molecular weight of 500 Preferably 10,000 to 10,000). Each of them may be used alone, or a plurality of them may be used in combination.

The polyester polyol is, for example, a condensate of a polycarboxylic acid and a low molecular weight polyol,
Those having a molecular weight of 500 to 10,000 are mentioned. Specifically, poly (ethylene adipate) (PEA), poly (diethylene adipate) (PDA), poly (propylene adipate) (PPA), poly (tetramethylene adipate) (PBA), poly (hexamethylene adipate) (PHA) ), Poly (neopentylene adipate)
(PNA), a polyol composed of 3-methyl-1,5-pentanediol and adipic acid, a random copolymer of PEA and PDA, a random copolymer of PEA and PPA, P
A random copolymer of EA and PBA, a random copolymer of PHA and PNA, or a caprolactone polyol obtained by ring-opening polymerization of ε-caprolactone, β-methyl-δ-valerolactone by ring opening with ethylene glycol The resulting polyols (all of which have a molecular weight of 5
00 to 10000). Each of them may be used alone, or a plurality of them may be used in combination.

Further, examples of the polyester-based polyol include a copolymer of at least one of the following acids and at least one of glycols. Examples of the acid include terephthalic acid, isophthalic acid, phthalic anhydride, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecane diacid, dimer acid (mixture), paraoxybenzoic acid,
Trimellitic anhydride, ε-caprolactone, β-methyl-δ valerolactone and the like.

As the glycol, ethylene glycol, propylene glycol, 1,4-butanediol,
1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, pentaerythritol, 3-methyl-1,5-pentanediol, and the like. Can be

As the polyester ether polyol, a half ester formed by reacting a polyether polyol with a dicarboxylic anhydride such as phthalic anhydride is subjected to dehydration condensation, or an alkylene oxide is added to the half ester in the presence of a basic catalyst or the like. Examples thereof include those obtained by addition.

As the polycarbonate polyol,
Conventionally known polyol (polyhydric alcohol) and phosgene,
Various molecular weights obtained by condensation with chloroformate, dialkyl carbonate or diallyl carbonate are known. Particularly preferred as such a polycarbonate-based polyol, as the polyol, 1,6-hexanediol, 1,4-butanediol, 1,3-butanediol, neopentyl glycol, or 1,5-pentanediol was used. Having a molecular weight of about 500 to 10,000. Each of them may be used alone, or a plurality of them may be used in combination.

The following can be used as the polybutadiene polyol. Examples of the hydroxyl group-containing liquid diene polymer include a diene polymer and a diene copolymer having a molecular weight of 600 to 3,000 and an average number of functional groups of 1.7 to 3.0, and having 4 to 12 carbon atoms. Copolymers with α-olefinic addition-polymerizable monomers of Formulas 2 to 2.2, and the like.

Specifically, butadiene homopolymer, isoprene homopolymer, butadiene-styrene copolymer, butadiene-isoprene copolymer, butadiene-
An acrylonitrile copolymer, a butadiene-2-ethylhexyl acrylate copolymer, a butadiene-n-octadecyl acrylate copolymer and the like can be exemplified. These liquid diene polymers can be produced, for example, by subjecting a conjugated diene monomer to a heat reaction in a liquid reaction medium in the presence of hydrogen peroxide.
Commercially available products include Poly-bd (trade name of ARCO) and NissoPB (trade name of Nippon Soda Co., Ltd.).

Furthermore, a mixture of two or more arbitrarily selected from these polyols, or a mixture of the polyol and a polyolefin-based polyol appropriately can be used.

Among the above polyols, preferred polyols have an average number of functional groups of 1 to 8 and a hydroxyl value of 10 to 600 mg.
At least one polyol selected from a polyoxyalkylene polyol having a KOH / g, a polyester polyol and a polyester ether polyol.
Further, a polyolefin-based polyol in which the double bond of the liquid diene-based polymer is saturated may be blended with the polyol component.

As the chain extender, those generally used when a urethane prepolymer is cured to form a polyurethane elastomer may be used. For example, a polyol compound, a polyamine compound and the like can be mentioned. As the polyol compound, a primary polyol, a secondary polyol,
Any of the tertiary polyols may be used. In particular,
Trimethylolpropane ("TMP"), ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, propylene glycol, dipropylene glycol, 1,2 -Butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 2,3-pentanediol, 2,5-hexanediol, 2,4-hexanediol, 2-ethyl- 1,3
-Hexanediol, cyclohexanediol, 2-ethyl-2- (hydroxymethyl) -1,3-propanediol and the like.

Examples of the polyamine compound include diamine, triamine, tetraamine and the like, primary amine, secondary amine,
Any of the tertiary amines can be used. Specifically, aliphatic amines such as hexamethylenediamine, 3,
Alicyclic amines such as 3'-dimethyl-4,4'-diaminodicyclohexylmethane, 4,4'-methylenebis-2
-Chloroaniline, 2,2'3,3'-tetrachloro-
Examples thereof include aromatic amines such as 4,4'-diaminophenylmethane and 4,4'-diaminodiphenyl, and 2,4,6-tris (dimethylaminomethyl) phenol.
One of these chain extenders may be used alone, or a plurality thereof may be used in combination. It is not necessary to use it.

The above-mentioned polyol or polymer-dispersed polyol and an organic polyisocyanate, if necessary, a chain extender,
To produce a urethane prepolymer. The obtained urethane prepolymer can be cured by a known method, including the mixing ratio of the chain extender to the urethane prepolymer, the curing temperature, the curing time, and the like. In the present invention, the polyurethane elastomer may contain additives and the like. Examples of the additive include a nonionic plasticizer, a flame retardant, a filler, a stabilizer, and a colorant.

Examples of the plasticizer include dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate (DOA), triethylene glycol dibenzoate, tricresyl phosphate, dioctyl phthalate, and pentaeristol. Fatty acid esters, dioctyl sebacate, diisooctyl azelate, dibutoxyethoxyethyl adipate and the like can be used.

[0038] As a method of obtaining a polyurethane elastomer, to obtain a urethane prepolymer by reacting the above polyol and an organic polyisocyanate, then Kusarinobe
There are a method of reacting a long agent, and a one-shot method of simultaneously reacting a polyol and an organic polyisocyanate at a predetermined ratio. In any case, a urethane-forming catalyst may be used.

As the urethanization catalyst, any of those usually used in the production of polyurethane can be used. For example, amine catalysts include triethylamine, tripropylamine, tributylamine, N, N, N ', N'
An organic metal catalyst such as tetramethylhexamethylenediamine, N-methylmorpholine, N-ethylmorpholine, dimethylcyclohexylamine, bis [2- (dimethylamino) ethyl] ether, triethylenediamine or a salt of triethylenediamine; Examples include tin, tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, lead octanoate, lead naphthenate, nickel naphthenate, and cobalt naphthenate. These catalysts can be arbitrarily mixed and used. The amount of use is 0.0001 to 10.0 parts by weight based on 100 parts by weight of the active hydrogen compound (polyol).

After the polyurethane elastomer having the above composition is molded into a sheet having a thickness of 2 mm, a DC electric field is applied to the sheet and the mechanical response thereof is measured using a strain sensor. At this time, there is also a method in which the polyurethane elastomer molded into a sheet is absorbed in advance and then dried appropriately before use. Thereafter, the upper and lower surfaces of the polyurethane elastomer molded into a plate shape are sandwiched between electrode plates, and a voltage is applied. The thickness change of the polyurethane elastomer is observed with a strain sensor, and the effects of potential, current, etc. are measured.

The present inventors have found that when the polyurethane elastomer is hydrated to some extent and then an electric field is applied, the magnitude of strain amplification and the electrostriction constant are higher. As a method for making the polyurethane elastomer contain water, there are 20 methods.
Immersed in water of about 100 ° C. for about 1 to 200 hours, and allowed to absorb water until a saturated state is reached.
Drying for about 200 hours to give a predetermined moisture content. The hydration and drying operations may be performed under normal pressure, increased pressure or reduced pressure. In consideration of increasing the amplification of strain when an electric field is applied, and increasing the electrostriction constant, the water content in the polyurethane elastomer is 0.01 to 0.01%.
A range of 50% by weight is preferred. More preferably 0.5 to
It is in the range of 10% by weight.

[0042]

The present invention will be described in more detail with reference to the following examples. In addition, each characteristic value shown in the Example was measured by the following method.

(1) Young's modulus (MPa) Tensilon RCT-1225 manufactured by Orientec Co., Ltd.
Use A. The pulling speed is 100 mm / min,
Other conditions conform to JIS K6301. The Young's modulus is calculated from a stress-strain curve having an elongation ratio in the range of 1.05 to 1.25.

(2) Breaking strength (MPa) and breaking elongation (%) Measured according to the method described in JIS A-6021.

(3) Strain Polyurethane elastomer sheet (length 25 mm, width 2)
(5 mm, thickness 2 mm), using the following device, applying a DC electric field under the following conditions, and measuring the mechanical response using a strain sensor. Applied voltage: DC voltage of 2.5 kV is applied for 2 minutes. DC power supply: manufactured by INTEX Co., Ltd .; type: HIGH VOLTAGE DC SU
PPLY V-710. Sensor for strain measurement device: Tra
nsducer assembly G. L. COLL
INS CORP. SS-203DC24V (sensitivity; 1
mV = 0.117 μm).

(4) Electrostriction constant (m ² / V ² ) Collection of Papers on Polymers (Vol. 56, No. 2, p. 69, 1999)
Is calculated using the following mathematical formula (1). S = ME ² (1) Here, S: strain, E: electric field strength (V / m), M: electrostriction constant (m ² / V ² ).

<Method for Preparing Polyurethane Elastomer>
In the following examples, each polyurethane elastomer was produced by the following procedure. A polyisocyanate is added to 100 parts by weight of a polyol at an equivalent ratio of NCO / OH of 1.
05 and mixed. The obtained mixture was poured into a mold, which was previously adjusted to 100 ° C. and had a thickness of 2 mm, under a nitrogen stream.
It was left in an oven at a day and a night to perform a curing reaction.

Preparation Example 1 <Polyurethane Elastomer Sheet A> (1) Preparation of Polymer-Dispersed Polyol A In the presence of a KOH catalyst, propylene oxide is added to glycerin and then ethylene oxide is added to polyether polyol A (hydroxyl value). 33mgKOH /
g, number average molecular weight 5000, EO content 14% by weight) 80
5 parts by weight of acrylamide, 3 parts by weight of acrylonitrile, and styrene at 100 ° C. in the presence of 0.5 parts by weight of 2,2′-azobis (2-methylbutyronitrile) as a radical initiator, 12 parts by weight were copolymerized to prepare a polymer-dispersed polyol A. The hydroxyl value of the polymer-dispersed polyol A is 28 mgK
OH / g. The amide group content of the copolymer in the polymer-dispersed polyol A was 15.5% by weight. Abbreviation of composition: AAM-AN-St. (2) Polyisocyanate Mitsui Cosmonate LK [trade name, manufactured by Mitsui Chemicals, diphenylmethane diisocyanate carbodiimide modified product, NCO% = 28.0] was used.

Preparation Example 2 <Polyurethane elastomer sheet B> A polymer-dispersed polyol was prepared in the same manner as in Example 1 except that 10 parts by weight of acrylamide and 10 parts by weight of styrene were used as monomers for producing the copolymer. B was produced. The hydroxyl value of the polymer-dispersed polyol B was 28 mgKOH / g, and the amide group content of the copolymer was 31.0% by weight. Abbreviation of composition: AAM-St. Next, a polyurethane elastomer sheet B was prepared in the same manner as in Preparation Example 1 except that the polymer-dispersed polyol B was used.

Comparative Preparation Example 1 <Polyurethane elastomer sheet C> A polyurethane elastomer sheet C was prepared in the same manner as in Preparation Example 1, except that polyether polyol A was used in place of polymer-dispersed polyol A. Abbreviation of composition: PPG.

Comparative Preparation Example 2 <Polyurethane elastomer sheet D> In the presence of a KOH catalyst, glycerin was added with ethylene oxide, and then propylene oxide was added, and the hydroxyl value was 56 mg.
A polyether polyol B (EO content 15% by weight) having a KOH / g and an average molecular weight of 3000 was produced. Then, using 60 parts by weight of polyether polyol B as a reaction medium,
At 100 ° C., 2,2′-
In the presence of 0.5 parts by weight of azobis (2-methylbutyronitrile), 12 parts by weight of acrylonitrile and styrene 2
8 parts by weight were polymerized to prepare a polymer-dispersed polyol D having a hydroxyl value of 44 mgKOH / g. Abbreviation of composition:
AN-St. Next, a polyurethane elastomer sheet D was prepared in the same manner as in Preparation Example 1 except that the polymer-dispersed polyol D was used.

The Young's modulus, breaking strength and breaking elongation of each urethane elastomer were measured by the above methods. The results obtained are shown in [Table 1].

Example 1 The polyurethane elastomer sheet A obtained in Preparation Example 1 was immersed in warm water at 80 ° C. for 60 hours. After the water content calculated from the weight loss became constant, the product was gradually dried, and the water content was adjusted to 1.5% by weight to obtain a polyurethane elastomer actuator A1. The distortion of the obtained polyurethane elastomer-based actuator A1 was measured by the above method. The electrostriction constant was calculated from the above formula (1) based on the obtained measurement values. The results obtained are shown in [Table 1].

Comparative Example 1 The polyurethane elastomer sheet A was not immersed in water.
A polyurethane elastomer actuator A2 was obtained in the same manner as in Example 1 except that the water content was changed to 0% by weight. The results obtained are shown in [Table 2].

Examples 2-3 Using the polyurethane elastomer sheet B obtained in Preparation Example 2, the water content was adjusted to 2.7% by weight and 0.7% by weight in the same manner as in Example 1. Except for the above, a polyurethane elastomer actuator B1 to B2 was obtained in the same manner as in Example 1. The strain was measured in the same manner as in Example 1, and the electrostriction constant was calculated. The results obtained are shown in [Table 1].

Comparative Example 2 The polyurethane elastomer sheet B was not immersed in water.
A polyurethane elastomer actuator B3 was obtained in the same manner as in Example 2, except that the water content was changed to 0% by weight. The results obtained are shown in [Table 2].

COMPARATIVE EXAMPLES 3-4 Except that the polyurethane elastomer sheet C obtained in Comparative Preparation Example 1 was used and the water content was adjusted to 0 or 0.9% by weight in the same manner as in Comparative Example 1 or Example 1. Example 1
In the same manner as in the above, polyurethane elastomer-based actuators C1 and C2 were obtained. The results obtained are shown in [Table 2].

Comparative Example 5 A polyurethane elastomer actuator D1 was obtained in the same manner as in Example 1 except that the polyurethane elastomer sheet D obtained in Comparative Preparation Example 2 was used and the water content was adjusted to 0.8% by weight. Was. The results obtained are shown in [Table 2].

[0059]

[Table 1]

[0060]

[Table 2]

<Description of [Table 1] and [Table 2]> [Table 1]
The symbols described in the above mean the following. POP-A: polymer-dispersed polyol-A, POP-B: polymer-dispersed polyol-B, polyol-A: polyether polyol-A, polyol-B: polyether polyol-B.

<Consideration of Examples> As shown in [Table 1] and [Table 2], in a polyurethane elastomer B using a polymer-dispersed polyol in which a vinyl polymer obtained by copolymerizing acrylamide is dispersed in a polyol, a water absorption rate was measured. Was 1.5% by weight, 0.7% by weight and 2.7% by weight, high mechanical strain and high electrostriction constant were obtained. Further, as described in Table 2, mechanical distortion could not be observed in polyurethane elastomer A, which is a vinyl polymer dispersion in which acrylamide was similarly copolymerized, because the water absorption was 0%. The polyurethane elastomer C containing no vinyl polymer has a water absorption of 0.9%.
%, The mechanical strain and the electrostriction constant exhibited low values. Furthermore, the polyurethane elastomer D in which the vinyl polymer dispersed in the polyol is acrylonitrile and styrene copolymer also has a water absorption of 0.8%.
% Showed low values of mechanical strain and electrostriction constant.

[0063]

According to the present invention, a shape change (strain amplification) of a polyurethane elastomer is efficiently induced by applying an electric field to a polyurethane elastomer produced from a polyol containing an amide group and a polyisocyanate while containing water. And can be used as a polyurethane elastomer-based actuator.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shiko Nishikawa 2-1-1 Tango-dori, Minami-ku, Nagoya, Aichi Prefecture Inside of Mitsui Chemicals, Inc. (72) Inventor Saku Izugawa 2-chome Tango-dori, Minami-ku, Nagoya, Aichi No. 1 F-term in Mitsui Chemicals, Inc. (Reference) 4J034 BA02 BA03 BA09 BA10 CA02 CA04 CA12 CA13 CA15 CB03 CB07 CB08 CC03 CC12 CC26 CC45 CC52 CC54 CC61 CC62 CC65 CC67 DA01 DB03 DB07 DF01 DF02 DF11 DF12 DF14 DF21 DF21 DF20 DF21 DG08 DG09 DG16 DG23 DG24 GA02 GA03 GA05 GA06 GA33 HA01 HA07 HB08 HC03 HC12 HC13 HC17 HC22 HC46 HC54 HC61 HC64 HC71 HC73 KA01 KB02 KC17 KC18 KC35 KD02 KD12 MA24 QB06 QB19 RA11 RA12

Claims (5)

[Claims] 1. A polyurethane elastomer actuator produced from at least one polyol selected from a polyol having an amide group and a polyol containing a polymer having an amide group, and a polyisocyanate, wherein the water content of the polyurethane elastomer actuator is Is 0.01 to 50% by weight, and has a characteristic of amplifying a strain based on the orientation of the polyurethane elastomer in the electric field direction by application of an electric field in the water-containing state. 2. The polyurethane elastomer actuator according to claim 1, wherein the content of the amide group unit in the polyol is 3 to 60% by weight. 3. The polyurethane elastomer actuator according to claim 1, wherein the polyol is a polyol containing a polymer having an amide group. 4. The polyurethane elastomer actuator according to claim 3, wherein the polyol containing an amide group-containing polymer is a polymer-dispersed polyol in which amide group-containing vinyl polymer fine particles are dispersed in the polyol. 5. The polyurethane elastomer actuator according to claim 1, wherein the polyurethane elastomer has an electrostriction constant of (5 to 100) × 10 ⁻¹⁷ m ² / V ² .