JPH02206640A - Acrylic elastomer composition - Google Patents

Abstract

PURPOSE:To obtain a composition effective for constituting element of battery or sensor, etc., having excellent electric conductivity by adding a salt-electrolyte substance and two same metallic monovalent salts of polymeric acid salt such as sulfonic acid-type and carboxylic acid-type to an acrylic elastomer. CONSTITUTION:(A) 100 pts.wt. polymer of alkyl acrylate having 1-8C alkyl and/or alkoxyalkyl acrylate having 2-8C alkoxyalkyl is optionally mixed with 20 pts.wt. plasticizer having low molecular weight and high permittivity (preferably alkylene carbonate) and mixed with (B) 5-100 pts.wt. salt-electrolyte substance miscible with at least one of the component A (preferably perchlorate, etc.) and (C) 20-400 pts.wt. salt of copolymer having polymeric acid salt of carboxylic acid-type, polymeric acid salt of sulfonic acid-type, or both acid salts, having same metallic monovalent salt as the component B (preferably Li salt) to afford the aimed composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to acrylic elastomer compositions. More specifically, the present invention relates to an acrylic elastomer composition that is excellent in electrical conductivity.

[Conventional technology]

JP-A-59-206,444 describes a conductive polymer material composition in which a water-soluble inorganic salt electrolyte material and a water-soluble polymer material are blended into a base polymer material made of thermoplastic resin or rubber. ing.

However, in this composition, there is insufficient compatibility between the base polymeric substance and the water-soluble polymeric substance, and if the water-soluble polymeric substance is used in a proportion exceeding a certain level, phase separation may occur. , the mechanical strength is reduced, and for these reasons, the amount of electrolyte that can be dissociated is also restricted, and as a result, it is not possible to increase the conductivity as much as expected.

Therefore, the present inventors conducted various studies in search of a method for increasing the conductivity of a base polymer material in the coexistence of an electrolyte material and a water-soluble polymer material. An acrylic elastomer, which is not exemplified in , is selected as the base polymer material, and this acrylic elastomer has strong polarity and has good compatibility with the water-soluble polymer material in the coexistence of an electrolyte material or a plasticizer. By discovering the property of having
Publication No. 7).

By the way, an acrylic elastomer composition consisting of such an acrylic elastomer, an electrolyte substance and a water-soluble polymer substance which are compatible with the acrylic elastomer, and preferably a plasticizer added thereto, can be used when a plasticizer is added. The conductivity obtained is 10-'s-em-1 (20°C, 55
%R). this is.

This is thought to be due to the following reasons: the Tg of the entire composition increased due to the addition of a water-soluble polymer substance with a high Tg, and the degree of dissociation and mobility did not increase much due to anion acting as a strong trap.

[Problem to be solved by the invention]

Therefore, with the aim of further increasing the conductivity of the acrylic elastomer composition, we have proposed a new polymer solid electrolyte that is added to the acrylic elastomer together with an electrolyte substance (Japanese Patent Application No. 75904/1982). .

The acrylic elastomer composition added with the new polymeric solid electrolyte proposed herein is preferably composed of an acrylic elastomer and a mixture of the same monovalent salt of a salt electrolyte material and a polymeric acid salt that are compatible with the polymer. Further, a low molecular weight high dielectric constant plasticizer is added thereto.

This acrylic elastomer composition has fine particles of a polymeric acid salt dispersed in an acrylic elastomer in which a salt electrolyte has been dissolved, and uses fast ion diffusion at the interface to improve ionic conductivity. .

An object of the present invention is to provide an acrylic elastomer composition that increases the ionic conductivity of the polymeric acid salt fine particles, thereby increasing the ionic diffusion rate at the interface and increasing the overall ionic conductivity. .

[Means to solve the problem]

Therefore, the object of the present invention is to provide (a) an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and/or (b)
) A polymer of alkoxyalkyl acrylate having an alkoxyalkyl group having 2 to 8 carbon atoms, a salt electrolyte substance compatible with the polymer, and the same monovalent acid salt of two types of polymers, sulfonic acid type and carboxylic acid type. This is achieved by forming an acrylic elastomer composition consisting of a mixture of salts, preferably further adding a low molecular weight high dielectric constant plasticizer.

Forming the acrylic elastomer used in the present invention (
Examples of the alkyl acrylate component a) include methyl acrylate, ethyl acrylate, n- or iso-propyl acrylate, n- or iso-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, Alkyl acrylates having an alkyl group having 1 to 8 carbon atoms (including those having a substituent such as a cyano group) such as n-octyl acrylate and 2-cyanoethyl acrylate are used, and preferably ethyl acrylate or n-butyl acrylate is used. used.

Examples of the alkoxyalkyl acrylate of component (b) include methoxymethyl acrylate, ethoxymethyl acrylate, 2-methoxyethyl acrylate, 2-
Alkoxyalkyl acrylates having an alkoxyalkyl group having 2 to 8 carbon atoms, such as ethoxyethyl acrylate and 2-butoxyethyl acrylate, are used, and 2-methoxyethyl acrylate and 2-ethoxyethyl acrylate are preferably used.

These components (a) and (b) are each used as a homopolymer, but generally have a polymer content of about 99.9 to 9
It is copolymerized and used at a ratio of 0 mol%, and when both components (a) and (b) are used, the former has a content of about 1% by mole.
The latter is generally used in a proportion of 0 to 90 mol %, with the latter being about 90 to 10 mol %.

A part of these components (a) and/or (b), specifically up to about 10 mol %, may be substituted with other copolymerizable monomers and copolymerized. Examples of such copolymerizable monomers include vinyl chloride, vinylidene chloride, acrylonitrile, styrene, vinyl acetate, ethyl vinyl ether, butyl vinyl ether, alkyl methacrylate, and alkoxyalkyl methacrylate.

Depending on the use of the acrylic elastomer, crosslinkable groups may be introduced therein. The following crosslinking agents are used depending on the type of component forming the crosslinking point and its reactive group.

(a) Epoxy group-containing vinyl monomer allyl glycidyl ether, glycidyl acrylate,
Glycidyl methacrylate is exemplified, and examples of crosslinking agents include polyamines such as diethylenetriamine and metaphenylenediamine, polycarboxylic acids such as adipic acid, acid anhydrides such as pyromellitic anhydride and maleic anhydride, and polyamides. and sulfonamides are used.

(b) Carboxyl group-containing vinyl monomers such as acrylic acid, methacrylic acid, and itaconic acid are exemplified, and examples of crosslinking agents for these include polyepoxides such as ethylene glycol diglycidyl ether and 1,6-hexanesiol diglycidyl ether. , 1,4-butanediol,
Polyols such as 1,1.1-trimethylolpropane are used. Instead of using these crosslinking agents, crosslinking may be performed only by heating.

(c) Reactive halogen-containing vinyl monomers Examples include 2-chloroethyl vinyl ether and monochloroacetic acid, and examples of crosslinking agents for these include diethylenetriamine,
Polyamines such as triethylenetetramine, polycarbamates such as hexamethylene diamine carbamate, etc. are used.

(d) Diene monomers divinylbenzene, piperylene, isoprene, pentadiene, vinylcyclohexene, chloroprene, butadiene, methylbutadiene, cyclopentadiene, methylpentadiene, ethylene glycol diacrylate, propylene glycol diacrylate, ethylene glycol dimethacrylate , propylene glycol dimethacrylate, etc. Examples of crosslinking agents include sulfur, organic peroxides such as benzoyl peroxide and dicumyl peroxide, azo compounds such as azobisisobutyronitrile, and divinylbenzene. , triallyl cyanurate, triallyl isocyanurate, etc. are used. Instead of using these crosslinking agents, crosslinking may be performed only by heating.

(e) Hydroxyl group-containing vinyl monomers Examples include hydroxyalkyl methacrylate, hydroxyalkoxy acrylate, and N-methylol acrylamide. Examples of crosslinking agents for these include polyisocyanates such as hexamethylene diisocyanate and tolylene diisocyanate, and adipine. Polycarboxylic acids such as acids, alkoxymethylmelamines such as methoxymethylmelamine, and the like are used.

(f) Amide group-containing vinyl monomers such as acrylamide and methacrylamide are exemplified, and as a crosslinking agent for these, aminoformaldehyde and the like are used, for example. Alternatively, crosslinking may be effected only by heating.

To explain the polymerization reaction of the above polymerizable monomers in terms of copolymerization reaction, the copolymerization reaction can be carried out by any method such as bulk polymerization method, emulsion polymerization method, suspension polymerization method, solution polymerization method, etc. For example, this is done as follows. In a flask equipped with a reflux condenser, a dropping funnel, and a stirrer, 100 parts by weight of solvent (approximately 5 to
98% by weight) and maintained at a predetermined temperature. In the dropping funnel, a monomer mixture of about 10 to 900
Add a solution in which about 1 to 10 parts by weight of a polymerization initiator is dissolved in 1 part by weight, and dropwise add it over about 0.5 to 5 hours.
Continue the reaction for ~5 hours. Under these reaction conditions, the polymerization rate is about 80 to 95%. In order to further increase the polymerization rate, after the monomer mixture has been added dropwise, add a polymerization initiator of about 1 to
By adding 5 parts by weight, the polymerization rate can be increased to 99% or more.

When such a dropwise polymerization method is adopted, there is an advantage that the copolymerization ratio of monomers having different reactivities is not much different between the start and end of polymerization, and a copolymer elastomer with a uniform composition can be obtained. In addition, when copolymerizing monomers with extremely different reactivities, a relatively uniform composition can be achieved by increasing the concentration of the monomer with low reactivity at the beginning of dropping and lowering the concentration at the end of dropping. A copolymer elastomer is obtained.

When the copolymerization reaction is carried out using a mercapto compound as a chain transfer agent in the polymerization reaction carried out in this manner, the resulting copolymer elastomer provides a crosslinked product with excellent vulcanization properties.

As the mercapto compound, ω-mercaptoalkanol, alkylmercaptan, allylmercaptan, mercaptocarboxylic acid, alkyldithiol, dithioglycerin, trithioglycerin, etc. are used, but preferably 2-mercaptoethanol, 3-mercaptopropanol, 4- An ω-mercaptoalkanol such as mercaptobutanol is used. These mercapto compounds are used in a proportion of about 0.1 to 3 mole %, preferably about 0.15 to 1 mole, based on the monomer mixture.

Another advantage of using these mercapto compounds is that the copolymerization ratio of the crosslinkable group-containing monomer can be increased. In general, increasing this copolymerization ratio makes gelation easier, but by using this chain transfer agent,
Even if a relatively large amount of the crosslinkable group-containing monomer, about 0.1 to 10 mol %, is copolymerized, the copolymerization can be effected without gelation.

Monovalent salt electrolyte substances that are compatible with the acrylic elastomer and are added to the acrylic elastomer thus polymerized together with the polymeric acid salt include hydrohalic acid, perhalogenated oxyacid, halogenated oxyacid, Alkali metal salts such as halogenated oxyacids, hypohalous oxyacids, tetrahalogenated boric acids, hexahalogenated phosphoric acids, trihalogenated metasulfonic acids, thiocyanic acids, nitric acids, sulfuric acids, phosphoric acids, carbonic acids, Ammonium salts, furthermore, organic carboxylates, organic sulfonates, various onium salts, quaternary ammonium salts, etc. are used, preferably perchlorates such as lithium perchlorate, and quaternary ammonium salts such as benzylpyridinium chloride. Thiocyanate salts such as , sodium thiocyanate, and lithium thiocyanate are used.

These monovalent salt electrolyte materials are used together with a polymeric acid monovalent salt having the same type of salt as the electrolyte material. The polymeric acid that forms such a monovalent salt is a homopolymer consisting of monomer units represented by the general formula (in the formula, R8 is hydrogen or an alkyl group having 1 to 5 carbon atoms), or It includes a copolymer in any proportion with a monomer unit represented by the formula (wherein R2 is hydrogen, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, or an aralkyl group).

In the present invention, such salts of sulfonic acid type and carboxylic acid type polymeric acids are used in combination in an amount of about 40 to 60% by weight, preferably about 40 to 60% by weight. Examples of sulfonic acid-type polymeric acids include polystyrene sulfonic acid, polyα-methylstyrene sulfonic acid, styrene-styrene sulfonic acid copolymer, polyethylene sulfonic acid, polypropylene sulfonic acid, and methyl acrylate.
A propylene sulfonic acid copolymer or the like is used. Further, as the carboxylic acid type polymeric acid, for example, polyacrylic acid, polymethacrylic acid, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, etc. are used. Moreover, instead of using both of these in combination, a copolymer having a sulfonic acid group and a carboxylic acid group, such as an ethylene sulfonic acid-acrylic acid copolymer, can also be used. The degree of polymerization of these 2tt2 polymeric acids is 10'' to 105, preferably 10' to 10''.

The polymeric acid is used as a monovalent salt such as an alkali metal salt such as a sodium salt or a lithium salt, or an ammonium salt, and is preferably used as a lithium salt. Polymeric acid salts are usually stored in the form of an aqueous solution of sodium salt, so if a monovalent salt other than the sodium salt is used, this aqueous solution is passed through an acid-form ion exchange resin to convert it into the acid form. After returning, it is used after being neutralized with an aqueous hydroxide solution having the same monovalent cation as the electrolyte substance used in combination.

The sulfonic acid type and carboxylic acid type polymeric acid salts are prepared separately as such neutralized aqueous solutions and then mixed, or the respective polymeric acid salt powders are mixed in water and then mixed with ethanol and methyl ethyl ketone. are added sequentially to reprecipitate particles with an average particle size of about 0.1 to 0.3 μm,
After spray drying, it is heated and dried at about 120 to 150° C. under reduced pressure before use.

The electrolyte substance and the polymeric acid salt each contain about 5 to 100 parts by weight, preferably about 30 to 50 parts by weight, and the latter about 20 to 100 parts by weight, respectively, based on 100 parts by weight of the acrylic elastomer.
400 parts by weight, preferably about 60 to 150 parts by weight, and the former is about 1 to 70% by weight of the total amount of both.
, preferably in a proportion of about 10 to 50% by weight.

In addition to these two, approximately 20 parts by weight of a low molecular weight high dielectric constant plasticizer is added to 100 parts by weight of the acrylic elastomer.

It is also preferably added in a proportion of about 5 to 15 parts by weight. Any plasticizer can be used as long as it has a polarity that dissociates the electrolyte, is nonvolatile, and is compatible with the acrylic elastomer, such as monovalent or polyvalent carboxylic acids. Although esters, triesters of phosphine oxide, sulfamide compounds, alkylene glycols or alkyl etherified products thereof may also be used, alkylene carbonate compounds such as ethylene carbonate and propylene carbonate are preferably used.

The composition is prepared by adding electrolyte substances to the acrylic elastomer and adding methyl ethyl ketone, dimethyl formamide,
A dispersion is prepared by adding two types of polymeric acid salt particles to a solution mixed and dissolved in an organic solvent such as dimethyl sulfoxide or hexamethylphosphoramide, and then stirring and dispersing the particles. If a dielectric constant plasticizer is added, it is added at this preparation stage. A film-like material is formed from this dispersion by a casting method or the like.

〔Effect of the invention〕

By using two types of sulfonic acid type and carboxylic acid type as the pentapolymer acid salt in an acrylic elastomer composition consisting of a mixture of an acrylic elastomer and the same monovalent salt of a salt electrolyte and a polymeric acid salt. ,
Its conductivity can be increased by about twice.

Film-like materials obtained from the acrylic elastomer composition of the present invention with improved ionic conductivity can be effectively used as constituent elements of batteries, sensors, display elements, and the like.

〔Example〕

Next, the present invention will be explained with reference to examples.

Example (A) Elastomer-low molecular salt mixture solution: A solution in which polyethyl acrylate Log and 2 g of lithium perchlorate were mixed and dissolved in 200 mQ of methyl ethyl ketone (B) Polymer acid salt particles: Poly(P-styrene sulfone) After mixing 6 g of lithium acrylate and stium polyacrylate in 200+* Q of water, 250 m Q of ethanol was added, and then 1000 m Q of methyl ethyl ketone was added dropwise with stirring to form particles with an average particle size of about 0.2 μm. After reprecipitation and spray drying, dry at 120° C. and 10-' Torr for 12 hours Sample IA: Add particles (B) to the above (A) solution, stir thoroughly, and then mix for 2 minutes. One dispersion sample nA: 2 g of propylene carbonate was added to the other dispersion, which was divided into two halves. Each of these samples was cast to a final thickness of about 1 mm.
00μm film, this was heated at 100℃, IF'To
After drying in rr for 24 hours, conductivity (20
(values determined from complex impedance plots at frequencies of 5 to 13 x 10'Hz) were measured at 20°C.

Comparative Example 1 In Samples IA and ■A, lithium polyacrylate was not used, and 10 g of only poly(P-lithium styrene sulfonate) was used as Samples IB and nB, respectively, and the film conductivity was measured in the same manner.

Comparative Example 2 In samples HA and ■A, poly(lithium P-styrene sulfonate) was not used, and only 10 g of lithium polyacrylate was used as samples IC and ■C, respectively, and the film conductivity was measured in the same manner.

The measurement results for the above Examples and Comparative Examples are shown in the following table.

table Example 1-”kμ yaw Example IA IA Comparative example I IB IB Comparative example 2 IC ■C Guide 1J■ΣEvening〔υ− 7,2X 10-' 1.8X10-' 4.2x 10”’ 8.3X10-' 1.5 x 10-' 4.7X 10-'

Claims (1)

[Scope of Claims] 1. A polymer of (a) an alkyl acrylate having an alkyl group having 1 to 8 carbon atoms and/or (b) an alkoxyalkyl acrylate having an alkoxyalkyl group having 2 to 8 carbon atoms, and the polymer An acrylic elastomer composition comprising a mixture of the same monovalent salt of a salt electrolyte substance which is compatible with the sulfonic acid type and two types of polymeric acid salts of the sulfonic acid type and the carboxylic acid type. 2. Polymers of (a) alkyl acrylates having an alkyl group having 1 to 8 carbon atoms and/or (b) alkoxyalkyl acrylates having an alkoxyalkyl group having 2 to 8 carbon atoms, low molecular weight high dielectric constant plasticizers, and these. An acrylic elastomer composition comprising a mixture of the same monovalent salt of a salt electrolyte substance that is compatible with at least one of the following: and two types of polymeric acid salts, a sulfonic acid type and a carboxylic acid type.