JP2005187697A - Conductive adhesive material having ionic conductivity - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conductive adhesive material composed of a polyurethane gel, having high ionic conductivity, causing little lowering of conductivity with time and having high adhesiveness. <P>SOLUTION: The conductive adhesive material is produced by mixing an adhesive polyurethane gel having an alkylene oxide segment with an ionic compound and a polar solvent having a saturated vapor pressure of ≤10 mmHg at 20°C. The lowering of conductivity and adhesiveness with time can be suppressed by using the ionic compound in combination with the low-volatile or nonvolatile polar solvent having a saturated vapor pressure of ≤10 mmHg at 20°C. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a high ion conductive pressure-sensitive adhesive material made of a polyurethane gel that is less likely to cause a decrease in conductivity over time.

  As this type of conductive adhesive, the ionic conductive polymer adhesive previously proposed by the present applicant, that is, a polyurethane polyol prepolymer having an alkylene oxide chain or / and a polyol having an alkylene oxide chain, and an alkylene oxide chain. There is known a pressure-sensitive adhesive material in which an ionic compound is contained in a polyurethane gel obtained by reacting a polyurethane polyisocyanate prepolymer having (Patent Document 1).

This non-hydrogel, one-component conductive adhesive material having a liquid polyalkylene oxide chain has a volume resistivity of the order of 10 ³ to 10 ⁴ Ω · cm by containing a small amount of water, and Since it has good adhesiveness, it is preferably used for applications such as dry bioelectrode materials. However, when the water content decreases or becomes anhydrous due to drying, the volume resistivity increases to the original 10 ⁴ to 10 ⁷ Ω · cm and the conductivity decreases, so that the bioelectrode material and other high conductivity However, it was difficult to use it for the required applications.
Japanese Patent Laid-Open No. 62-139628

  The present invention has been made to address the above problems, and provides a conductive adhesive material made of polyurethane gel that has high ionic conductivity and is less likely to cause a decrease in conductivity over time due to evaporation of moisture. Is a solution issue.

  In order to solve the above-described problems, the conductive adhesive material of the present invention contains an ionic compound and a polar solvent having a saturated vapor pressure at 20 ° C. of 10 mmHg or less in an adhesive polyurethane gel having an alkylene oxide segment. It is characterized by being.

In the conductive adhesive material of the present invention, 20 to 400 parts by weight of a polar solvent is contained in 100 parts by weight of the polyurethane gel, and the ionic compound is the number of moles of ether oxygen of the alkylene oxide of the polyurethane gel and the ether in the molecule of the polar solvent. It is preferable to contain so that it may become 2/100-10/100 mole number of the total mole number with the mole number of oxygen. The polar solvent is preferably a single solvent of diglyme, triglyme, tetraglyme, propylene carbonate, γ-butyrolactone, or ε-caprolactone, or a mixed solvent of two or more, and diglyme, triglyme, tetraglyme. , Propylene carbonate, γ-butyrolactone, ε-caprolactone, or a mixed solvent of two or more and ethylene carbonate is also preferably used. The conductive adhesive material of the present invention has an initial volume resistivity of 10 ² to 10 ⁴ Ω · cm, an initial adhesive force of 60 to 610 gf / 25 mm width according to JIS Z0237 180-degree peeling method, and a 45 ° C. Those having a volume resistivity and adhesive strength within the above-mentioned range even after being left in an oven for 1 week are preferable.

  In the conductive pressure-sensitive adhesive material of the present invention, ether oxygen present in the alkylene oxide segment of the polyurethane gel forms a complex with the ionic compound to disperse the ions, and when the potential is applied to the polyurethane gel, the ions move. To develop conductivity. At this time, when the polar solvent is contained in the polyurethane gel like the conductive adhesive material of the present invention, the movement of the gel segment dissolved in the polar solvent and the movement of ions are facilitated, and the conductivity is improved. This polar solvent has a low saturated vapor pressure at 20 ° C. of 10 mmHg or less and is difficult to diffuse from the polyurethane gel at room temperature and normal pressure. Therefore, it often causes a decrease in conductivity with time due to a decrease in the polar solvent. And good conductivity can be maintained.

In particular, 100 parts by weight of the polyurethane gel contains 20 to 400 parts by weight of a polar solvent, and the ionic compound is a total mole of the number of moles of ether oxygen in the alkylene oxide of the polyurethane gel and the number of moles of ether oxygen in the molecule of the polar solvent. The conductive adhesive contained so as to have a molar number of 2/100 to 10/100 of the number has a volume resistivity of about 10 ² to 10 ³ Ω · cm, as supported by experimental data described later. It has high conductivity. When the polar solvent is less than 20 parts by weight, the conductivity is lowered, and when it exceeds 400 parts by weight, the strength and adhesiveness of the polyurethane gel are lowered. Further, when the number of moles of the ionic compound is less than 2/100 of the total number of moles, the conductivity is lowered. When the number of moles of the ionic compound is more than 10/100 of the total number of moles, complex formation with ether oxygen is more than necessary. Thus, the movement of the alkylene oxide segment is suppressed and hardened, so that the conductivity and the adhesiveness are lowered.

  All of the above diglyme, triglyme, tetraglyme, propylene carbonate, γ-butyrolactone, and ε-caprolactone are non-volatile or low-volatile polar solvents having a saturated vapor pressure of 0.01 to 3 mmHg at 20 ° C. or 25 ° C. Therefore, the conductive adhesive containing this can maintain good conductivity for a long time. Ethylene carbonate has a low saturated vapor pressure at 36.4 ° C., as low as 0.02 mmHg, but has a melting point of 36.4 ° C., so it must be contained as a mixed solvent with each of the above polar solvents. A conductive adhesive containing a mixed solvent can maintain good conductivity over a long period of time.

  Hereinafter, specific embodiments of the present invention will be described in detail.

  The polyurethane gel used as the base material of the conductive adhesive material of the present invention is an adhesive polyurethane gel having an alkylene oxide segment. For example, polyol components A to D having the following structural formula and polyisocyanate components E to I are reacted. Thus, a segment polyurethane of a so-called three-dimensional penetration network obtained by urethane-bonding the —OH group and —NCO group of both components.

（Ｒ１，Ｒ２はアルキル化合物、脂環式化合物、芳香族化合物のいずれかでありＡＯはアルキレンオキサイドのセグメントである。）

(R1 and R2 are alkyl compounds, alicyclic compounds, or aromatic compounds, and AO is an alkylene oxide segment.)

（ＡＯはアルキレンオキサイドのセグメントであり、ｌは１又は４である。）

(AO is an alkylene oxide segment, and 1 is 1 or 4.)

（ＡＯはアルキレンオキサイドのセグメントである。）

(AO is an alkylene oxide segment.)

（ＡＯはアルキレンオキサイドのセグメントであり、Ｒは水素原子もしくはアルキル化合物、脂環式化合物、芳香族化合物のいずれかである。）

(AO is an alkylene oxide segment, and R is a hydrogen atom, an alkyl compound, an alicyclic compound, or an aromatic compound.)

（Ｒはアルキル基、脂環式化合物、芳香族化合物のいずれかであり、ＡＯはアルキレンオキサイドのセグメントである。）

(R is an alkyl group, alicyclic compound, or aromatic compound, and AO is an alkylene oxide segment.)

（Ｒはアルキル基、脂環式化合物、芳香族化合物のいずれかであり、ＡＯはアルキレンオキサイドのセグメントである。）

(R is an alkyl group, alicyclic compound, or aromatic compound, and AO is an alkylene oxide segment.)

（Ｒはアルキル基、脂環式化合物、芳香族化合物のいずれかであり、ＡＯはアルキレンオキサイドのセグメントであり、ｌは１又は４である。）

(R is an alkyl group, an alicyclic compound, or an aromatic compound, AO is an alkylene oxide segment, and 1 is 1 or 4.)

（Ｒはアルキル基、脂環式化合物、芳香族化合物のいずれかであり、ＡＯはアルキレンオキサイドのセグメントである。）

(R is an alkyl group, alicyclic compound, or aromatic compound, and AO is an alkylene oxide segment.)

（Ｒはアルキル基、脂環式化合物、芳香族化合物のいずれかであり、ＡＯはアルキレンオキサイドのセグメントである。）

(R is an alkyl group, alicyclic compound, or aromatic compound, and AO is an alkylene oxide segment.)

  The prepolymer as the polyol component listed in the structural formulas A to D will be described. The structural formula A is a polyurethane polyol prepolymer which is a reaction product of a polyether polyol and a diisocyanate, and both terminal components are composed of a polyether polyol. The terminal is an —OH group. The diisocyanate compound used here is the same as that in the polyurethane polyisocyanate prepolymer described later. For example, phenylene diisocyanate, 2,4-toluylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate ( MDI), naphthalene-1,5-diisocyanate, hexamethylene diisocyanate (HMDI), tetramethylene diisocyanate (TMDI), lysine diisocyanate, xylylene diisocyanate (XDI), water-added TDI, hydrogenated MDI, dicyclohexyldimethylmethane-p, p '-Diisocyanate, diethyl fumarate diisocyanate, isophorone diisocyanate (IPDI) and the like can be arbitrarily used.

  Structural formula B is obtained by adding polyether polyol to glycerol (1 = 1) or sorbitol (1 = 4), and structural formula C is obtained by adding polyether to trimethylolpropane. Similarly, 1,2,6-hexanetriol of the following structural formula J, trimethylolethane of the structural formula K, pentaerythlit slit of the structural formula L, polyglycerin of the structural formula M (n = 2 to 30) and its Adducts of polyhydric alcohols such as partial esters and polyether polyols can also be used.

  Structural formula D is a polyether polyol having an alkylene oxide segment, where both ends are —OH groups, and one end is blocked with an alkyl group, aromatic group, etc. Available at:

  Next, the polyisocyanate prepolymer shown in the structural formulas E to I will be described. In the structural formula E, two molecules of triisocyanate obtained by reacting diisocyanate with trimethylolpropane are converted into two molecules of alkylene oxide (AO). It is a quantified tetraisocyanate that is tetrafunctional. A tetraisocyanate having the structural formula F is obtained by using glycerol instead of trimethylolpropane. Since this type of tetraisocyanate tends to dimerize triisocyanate with 2 or 3 molecules of AO, it is necessary to finely control the reaction. Therefore, although unreacted triisocyanate is mixed, when reacting with polyol, the size of segment polyurethane molecules varies, which may act on the side convenient for controlling the adhesiveness.

  Structural formula G is obtained by reacting diisocyanate with the polyol of structural formula B. Similarly, structural formula H is a trifunctional compound obtained by reacting a polyol of structural formula C with a diisocyanate. Structural formula I is a reaction product of polyether polyol and diisocyanate and is bifunctional.

  In the alkylene oxide segment represented by AO in the above structural formulas A to I, the ratio of the ether oxygen to the carbon number of the methylene group is relatively large in consideration of enhancing conductivity, and the ionic compound and the complex Since it is desirable to have many opportunities to form, specifically, hydrophilic ethylene oxide (EO), hydrophobic propylene oxide (PO), and these EO-PO copolymers [for example, represented by the following structural formula N Block copolymers,-(PO-EO-EO-PO) m-,-(PO-PO-EO) m-,-(EO-EO-PO) m-,-(EO-PO-EO-) PO) m- and other alternating copolymers (m is a positive number of 1 or more), random copolymers of EO and PO, etc., hydrophobic butylene oxide (BO), BO-EO copolymers Etc. are suitable .

  In order to obtain a polyurethane gel having good adhesiveness, most or all of the above AO segments are desirably liquid at room temperature, and therefore the molecular weight is restricted. The molecular weight MW of the EO segment is suitably 150-1000, preferably 300-800. On the other hand, the PO segment is a liquid even if its molecular weight is tens of thousands, and the range of molecular weight that can be used is wide. However, the smaller the end group ratio, the lower the reaction probability, and in the case of a very long segment, the polyurethane gel is rich in fluidity and poor in shape retention, so a range of about 200 to several thousand is appropriate.

  In addition, the fluidity (softness) and the adhesiveness of EO-PO copolymers are affected by their ratio and arrangement. For example, in the block copolymer, when the molar fraction of PO is high, it is liquid even if the molecular weight is high, but even if the molar fraction of PO is low, it is liquid if the molecular weight of EO is low. However, as mentioned above, if the molecular weight of PO is high, problems such as shape retention occur. Therefore, a liquid EO-PO copolymer having a molecular weight of 600 to 8000, preferably 800 to 6000 is used at room temperature. .

  Since the BO segment becomes solid when the degree of polymerization is large, the preferred molecular weight range is 300 to 3000, and the molecular weight of the BO-EO copolymer is several hundred to several thousand, which is not much different from that of the EO-PO copolymer. .

  The polyurethane gel having each AO segment having a molecular weight as described above exhibits good adhesiveness because most or all of the AO segments are liquid at room temperature and have an appropriate molecular length (segment length). The AO segment having an appropriate molecular length is effective as a “field” in which the ether oxygen forms a complex with various ionic compounds, thereby exhibiting good conductivity as described above.

  In order to obtain a polyurethane gel having a relatively bulky three-dimensional network structure with good adhesion, the number of functionalities of the polyol component and the polyisocyanate component should be a combination of one bifunctional and the other trifunctional or higher. Or a combination of three or more functional groups. However, when reacting those having a functional number of 3 or more, the network chain concentration becomes too high, so if there is no very long AO segment, the elasticity exceeds the viscosity and it is difficult to obtain good adhesiveness. The retention of compounds and polar solvents is also reduced. Therefore, the preferred functional number of both components is a combination of about 2 to 4, and this combination makes it easy to control the tackiness and the like.

  The reaction ratio between the polyol component and the polyisocyanate component is such that the ratio of the functional groups at the ends, that is, the value of OH / NCO is 1 ≦ OH / NCO ≦ 5 in order to obtain a polyurethane gel with good tackiness. It is desirable to regulate. In this way, in the state where the OH / NCO value is 1 or more and 5 or less, it can be imagined that a straight segment having an OH group at the end in a group of bulky molecules moves freely with a tail. This works to improve the tackiness. The free tail becomes longer and larger as the OH / NCO value is closer to 5. If OH / NCO is less than 1, unreacted -NCO remains and causes a post-reaction, so it is necessary to set it to 1 or more.

  The range of molecular weight of polyol and polyisocyanate varies in a wide range depending on the type of AO or isocyanate, molecular shape, whether AO is a homopolymer or a copolymer, etc., but it is approximately 1400 to 10,000 for polyurethane polyol prepolymer, Approximately 150 to 6000, and approximately 500 to 10,000 for the polyurethane polyisocyanate prepolymer. Preferably, each can be selected in the range of about 1000 to 6000, about 300 to 3000, and about 1000 to 6000.

  Various metal salts are used as the ionic compound to be contained in the polyurethane gel. Among them, sodium chloride, potassium chloride, lithium chloride, lithium perchlorate, potassium chlorate, lithium borofluoride, sodium thiocyanate, trifluoride are used. An alkali metal salt that easily forms a complex with the ether oxygen of the AO segment, such as lithium methanesulfonate, is suitable. In particular, a lithium salt is preferably used because of excellent ion conductivity. Among lithium salts, lithium perchlorate is optimal because it easily dissolves in a polar solvent having a low saturation vapor pressure described later, forms a complex with ether oxygen, and exhibits high conductivity.

  Such an ionic compound is 2/100 to 10/100 of the total number of moles of ether oxygen in the AO segment of the polyurethane gel and the number of moles of ether oxygen in the molecule of the polar solvent described later contained in the polyurethane gel. It is desirable to adjust the content so that it is contained in the polyurethane gel so as to be the number of moles. When the number of moles of the ionic compound is within the above range, good conductivity and adhesiveness are expressed. However, when the number of moles of the ionic compound is less than 2/100 of the total number of moles, the conductivity is lowered. When it exceeds 10/100 of the total number of moles, complex formation with ether oxygen is increased more than necessary, and the movement of the AO segment is suppressed and hardened, resulting in inconvenience that conductivity and adhesiveness are lowered.

  The number of moles of ether oxygen in the AO segment is determined by dividing the molecular weight of the AO segment by the molecular weight of the alkylene unit. When the AO segment is made of, for example, polyethylene glycol (PEG) having a molecular weight of 400, a value obtained by dividing this by the molecular weight 44 of the ethylene unit, that is, 400/44 is the number of moles of ether oxygen. In addition, ether oxygen in the molecule of the polar solvent to be described later is in principle counted, but exceptionally, for ethylene carbonate and propylene carbonate, the number of ether oxygen is set to 1 from its unique structural formula, For the glyme-based ether oxygen, the ether oxygen of diglyme is 2, the ether oxygen of triglyme is 3, and the ether oxygen of tetraglyme is 4.

  On the other hand, the polar solvent contained in the polyurethane gel dissolves the ionic compound to facilitate the formation of a complex with the ether oxygen of the AO segment and the movement of the ions, and exhibits good conductivity. It plays a role of maintaining for a long time, and it is necessary to use a polar solvent having a saturated vapor pressure at 20 ° C. of 10 mmHg or less. A polar solvent having a saturated vapor pressure higher than 10 mmHg evaporates in a relatively short time at room temperature and normal pressure and dissipates from the polyurethane gel. Therefore, it is difficult to maintain good conductivity for a long time. It is unsuitable as a polar solvent used in the present invention. A preferable saturated vapor pressure of the polar solvent is 5 mmHg / 20 ° C, and a more preferable saturated vapor pressure is 0.01 to 3 mmHg / 20 ° C.

  Such polar solvents include diglyme (3 mmHg / 20 ° C.), triglyme (0.9 mmHg / 20 ° C.), tetraglyme (0.01 mmHg / 20 ° C.), propylene carbonate (0.03 mmHg / 20 ° C.), γ-butyrolactone ( 0.45 mmHg / 25 ° C.), ε-caprolactone (0.135 mmHg / 25 ° C.) and the like, and these are contained alone or in combination of two or more in the polyurethane gel. All of these polar solvents have a boiling point in the range of 162.0 to 275.3 ° C. and, in combination with the saturation pressure as low as 3 mmHg / 20 ° C. or less, are extremely low volatility or substantial at room temperature and normal pressure. It is a non-volatile solvent and does not substantially dissipate from the polyurethane gel, and is retained in the polyurethane gel for a long time with the ionic compound dissolved. In addition, although γ-butyrolactone and ε-caprolactone have a saturated vapor pressure of 25 ° C., the saturated vapor pressure of 20 ° C. is lower than this, so that these have a saturated vapor pressure of 10 mmHg or less at 20 ° C. It is clear that this is a polar solvent.

  Ethylene carbonate (0.02 mmHg / 36.4 ° C.) is also a preferred polar solvent. Since this ethylene carbonate has a melting point of 36.4 ° C. and is solid at room temperature, any one of the above diglyme, triglyme, tetraglyme, propylene carbonate, γ-butyrolactone, and ε-caprolactone is at least two. It is mixed and contained in the polyurethane gel.

The polar solvent is preferably contained in the range of 20 to 400 parts by weight with respect to 100 parts by weight of the polyurethane gel. Within this range, when the polar solvent is contained in the polyurethane gel and the ionic compound is contained in the above content, a highly conductive pressure-sensitive adhesive material having a volume resistivity of about 10 ² to 10 ³ Ω · cm is obtained. If the content of the polar solvent is less than 20 parts by weight, the conductivity is lowered, and if it exceeds 400 parts by weight, the strength and adhesiveness of the polyurethane gel are lowered, which is not preferable.

  Such a conductive adhesive material can be easily manufactured, for example, by the following method. That is, a solution obtained by dissolving an ionic compound in a polar solvent is dissolved in either a liquid polyol component or a polyisocyanate component, and both components are mixed and reacted to obtain a polyurethane gel conductive adhesive. Alternatively, an ionic compound may be dissolved in a mixed solvent of a polar solvent and a liquid polyol component, and this may be mixed and reacted with a polyisocyanate component to obtain a conductive adhesive material. Alternatively, a polyol component and a polyisocyanate component may be mixed and reacted to create a polyurethane gel, and a solution obtained by dissolving an ionic compound in a polar solvent may be absorbed into the polyurethane gel to obtain a conductive adhesive material.

  For the purpose of increasing the strength of the gel, a synthetic resin nonwoven fabric may be embedded in the surface layer portion or the intermediate layer portion of the polyurethane gel.

  The conductive adhesive material as described above can be suitably used for various applications such as a touch panel (EL panel), a pressure switch, and a solid electrolyte of a battery as well as a biomedical electrode.

  Next, more specific examples and comparative examples of the present invention will be described.

[Example 1]
The conductive adhesive material of Example 1 was produced with the composition shown in Table 1 below. That is, 49.3 parts by weight (33.77 wt%) of EO-PO random copolymer diol which is a polyol component and 7.4 parts by weight (5.07 wt%) of monomethoxy PEG and ethylene carbonate / propylene carbonate which is a polar solvent In a mixed solution of 40 parts by weight (equal mole) of mixed solvent (27.40 wt%), 6 parts by weight of lithium perchlorate (4.11 wt% as an ionic compound, this is the number of moles of ether oxygen and the number of moles of polar solvent. And 43.3 parts by weight (29.66 wt%) of EO-PO random copolymerized triisocyanate, which is a polyisocyanate component, is sufficiently added. After mixing, an appropriate amount of an organotin catalyst was further added and mixed. The blended solution was degassed under reduced pressure, and the blended solution was poured into a mold on the release film and reacted at 60 ° C. for 3 hours to prepare a 1 mm polyurethane gel conductive adhesive.

  The obtained conductive adhesive material was punched into a circle with a diameter of 25 mm to prepare a sample. The sample immediately after the manufacture was sandwiched between two SUS plates (50 mm square, thickness 1 mm), and an LCR meter (Hewlett Packard). The electrical conductivity was examined by measuring the volume resistivity (Ω · cm) under the condition of 1VP-P × 1 kHz. The results are shown in Table 1 below.

  Also, a primer-treated polyethylene terephthalate (PET) film (thickness: 50 μm) was bonded to one side of the obtained conductive adhesive material, and this was cut into 25 mm (width) × 150 mm (length) samples. Was made. This sample was affixed to a SUS plate, and the adhesion was examined by performing a peeling test at a speed of 300 mm / min by the 180-degree peeling method of JIS Z0237.

Further, the obtained conductive adhesive material was allowed to stand for 1 week in a GAO oven at 45 ° C., and the conductivity and adhesive force after 1 week were examined in the same manner as described above using the left conductive adhesive material. The results are shown in Table 1 below.

[Examples 2 and 3]
As shown in Table 1 below, the blending amount of the ethylene carbonate / propylene carbonate mixed solvent as the polar solvent is changed from 40 parts by weight to 120 parts by weight (52.59 wt%) with respect to 100 parts by weight of the polymer component. With the change of the polar solvent, the blending amount of lithium perchlorate was 8.2 parts by weight (3.59 wt%, which is the sum of the number of moles of ether oxygen in the polyurethane gel and the number of moles of ether oxygen in the polar solvent. A conductive adhesive material of Example 2 having a thickness of 1 mm was produced in the same manner as in Example 1 except that it was changed to 2.5 / 100 of the number of moles).

  As shown in Table 1 below, the blending amount of the polar solvent, ethylene carbonate / propylene carbonate mixed solvent, was changed from 40 parts by weight to 350 parts by weight (75.32 wt%) with respect to 100 parts by weight of the polymer component. As the polar solvent is changed, the amount of lithium perchlorate is changed to 14.7 parts by weight (3.16 wt%, the number of moles of ether oxygen in the polyurethane gel and the number of moles of ether oxygen in the polar solvent). The conductive adhesive material of Example 3 having a thickness of 1 mm was produced in the same manner as in Example 1 except that the total number of moles was 2.5 / 100.

  About the electroconductive adhesive material of these Examples 2 and 3, it carried out similarly to Example 1, and investigated the electroconductivity and adhesive force immediately after preparation and 1 week after progress. The results are shown in Table 1 below.

[Comparative Examples 1 and 2]
As shown in Table 1 below, the blending amount of the polar solvent ethylene carbonate / propylene carbonate mixed solvent is changed to 10 parts by weight (8.68 wt%) with respect to 100 parts by weight of the polymer component. Accordingly, the blending amount of lithium perchlorate was 5.2 parts by weight (4.51 wt%, which is 2.5 / of the total number of moles of ether oxygen in the polyurethane gel and moles of ether oxygen in the polar solvent. A conductive adhesive material of Comparative Example 1 having a thickness of 1 mm was produced in the same manner as in Example 1 except that it was changed to 100).

  As shown in Table 1 below, the blending amount of the ethylene carbonate / propylene carbonate mixed solvent, which is a polar solvent, is changed to 500 parts by weight (80.80 wt%) with respect to 100 parts by weight of the polymer component. In accordance with the change, the blending amount of lithium perchlorate was 18.8 parts by weight (3.04 wt%, which was 2.4 of the total number of moles of ether oxygen in the polyurethane gel and the mole of ether oxygen in the polar solvent. A conductive adhesive material of Comparative Example 2 having a thickness of 1 mm was produced in the same manner as in Example 1 except that it was changed to 5/100).

  About the electroconductive adhesive material of these comparative examples 1 and 2, it carried out similarly to Example 1, and investigated the electroconductivity and adhesive force immediately after preparation and 1 week after progress. The results are shown in Table 1 below.

[Examples 4 and 5]
As shown in Table 1 below, 40 parts by weight (27.38 wt%) of γ-butyrolactone is blended as a polar solvent with respect to 100 parts by weight of the polymer component, and accordingly, the blending amount of lithium perchlorate is 6. Example except that it was changed to 1 part by weight (4.18 wt%, which corresponds to 2.5 / 100 of the total number of moles of ether oxygen in the polyurethane gel and the mole of ether oxygen in the polar solvent) In the same manner as in Example 1, a conductive adhesive material of Example 4 having a thickness of 1 mm was produced.

  Further, as shown in Table 1 below, 40 parts by weight (27.25 wt%) of tetraglyme as a polar solvent is blended with 100 parts by weight of the polymer component, and accordingly, the blending amount of lithium perchlorate is 6 .8 parts by weight (4.63 wt%, which corresponds to 2.5 / 100 of the total number of moles of ether oxygen in the polyurethane gel and the number of moles of ether oxygen in the polar solvent) In the same manner as in Example 1, a conductive adhesive material of Example 5 having a thickness of 1 mm was produced.

  About the electroconductive adhesive material of these Examples 4 and 5, it carried out similarly to Example 1, and investigated the electroconductivity and adhesive force immediately after preparation and 1 week after progress. The results are shown in Table 1 below.

[Comparative Examples 3 and 4]
As shown in Table 1 below, 40 parts by weight (27.38 wt%) of monoglyme is blended as a polar solvent with respect to 100 parts by weight of the polymer component, and accordingly the blending amount of lithium perchlorate is 6.1 weights. Parts (4.18 wt%, which corresponds to 2.5 / 100 of the total number of moles of ether oxygen in the polyurethane gel and the number of moles of ether oxygen in the polar solvent). Similarly, a conductive adhesive material of Comparative Example 3 having a thickness of 1 mm was produced.

  About this electroconductive adhesive material, it carried out similarly to Example 1, and investigated the electroconductivity and adhesive force immediately after preparation and 1 week after progress. The results are shown in Table 1 below.

[Comparative Example 4]
A conductive adhesive material of Comparative Example 4 having a composition shown in Table 1 below was produced by the following method. That is, lithium perchlorate 4 was added to a mixed solution of 49.3 parts by weight (33.77 wt%) of an EO-PO random copolymer diol as a polyol component and 7.4 parts by weight (5.07 wt%) of monomethoxy PEG. 9.9 parts by weight (3.92 wt%, which corresponds to 2.5 / 100 of the total number of moles of ether oxygen in the polyurethane gel and the number of moles of water to be permeated later) After adding 43.3 parts by weight (34.67 wt%) of EO-PO random copolymerized triisocyanate, which is a polyisocyanate component, and mixing well, an appropriate amount of an organotin catalyst was further added and mixed. Using this blended solution, a polyurethane gel having a thickness of 1 mm was produced in the same manner as in Example 1, and this polyurethane gel was further allowed to stand for 36 hours in a 45 ° C. humidifier with a relative humidity of 90%. Then, 20 parts by weight (16.01 wt%) of water was absorbed to produce the conductive adhesive material of Comparative Example 4.

  About this electroconductive adhesive material, it carried out similarly to Example 1, and investigated the electroconductivity and adhesive force immediately after preparation and 1 week after progress. The results are shown in Table 1 below.

  From Comparative Example 1, Examples 1 to 3 and Comparative Example 2 in Table 1, the content of the mixed solvent of ethylene carbonate / propylene carbonate, which is a polar solvent, is increased. It can be seen that when the number of moles is increased to 2.5 / 100 of the total number of moles of the polar solvent, the initial conductivity is lowered and the conductivity is improved. And any of the conductive electrodes of Comparative Example 1, Examples 1 to 3 and Comparative Example 2 have almost the same volume resistivity after one week as the initial volume resistivity, and are conductive even after time. It can be seen that there is no substantial reduction. Moreover, it turns out that adhesiveness falls, so that content of a polar solvent increases.

The conductive adhesives of Examples 1, 2, and 3 in which the polar solvent content is in the range of 20 to 400 parts by weight with respect to 100 parts by weight of the polymer component, that is, the polyurethane gel, have a volume resistivity of 10 ² to 10 ³ Ω. -It has excellent conductivity in the order of cm, and has an adhesive strength by a peeling test in the range of 70 to 600 gf / 25 mm, which is suitable for practical use. In contrast, the conductive pressure-sensitive adhesive material of Comparative Example 1 in which the content of the polar solvent is 10 parts by weight with respect to 100 parts by weight of the polyurethane gel has an initial volume resistivity and a volume resistivity of 10 after one week. It is on the order of ⁴ Ω · cm, indicating that it is unsuitable for applications requiring high conductivity. Moreover, the conductive adhesive material of Comparative Example 2 in which the content of the polar solvent is 500 parts by weight with respect to 100 parts by weight of polyurethane is inferior with an initial adhesive force of 33 gf / 25 mm and an adhesive force after one week of 21 gf / 25 mm. It can be seen that it does not have a practical adhesiveness. From these things, it turns out that it is essential to make content of a polar solvent into 20-400 weight part with respect to 100 weight part of polyurethane gel.

In addition, the conductive adhesive materials of Examples 4 and 5 containing γ-butyrolactone and tetraglyme having a saturated vapor pressure of 10 mmHg or less as a polar solvent have good initial volume resistivity on the order of 10 ³ Ω · cm. Even if one week passes, there is no substantial decrease in conductivity, and the adhesive strength at the initial stage and after one week is very good at around 600 gf / 25 mm. On the other hand, the conductive adhesive of Comparative Example 3 containing monoglyme having a saturated vapor pressure of 48 mmHg at 20 ° C., and the conductive property of Comparative Example 3 containing water having a saturated vapor pressure of 17.5 mmHg at 20 ° C. All of the adhesive materials have good initial volume resistivity on the order of 10 ³ Ω · cm, but the volume resistivity after one week has increased to the order of 10 ⁴ Ω · cm, and the conductivity has decreased over time. You can see that it happens. From this, it can be seen that it is essential to contain a polar solvent having a saturated vapor pressure at 20 ° C. of 10 mmHg or less in order not to cause the electrical conductivity over time.

Claims (5)

  A conductive pressure-sensitive adhesive material having ion conductivity, characterized in that an adhesive polyurethane gel having an alkylene oxide segment contains an ionic compound and a polar solvent having a saturated vapor pressure at 20 ° C. of 10 mmHg or less.   20 to 400 parts by weight of a polar solvent is contained in 100 parts by weight of the polyurethane gel, and the ionic compound is the total number of moles of ether oxygen of the alkylene oxide of the polyurethane gel and the number of moles of ether oxygen in the molecule of the polar solvent. The conductive adhesive material according to claim 1, which is contained so as to have a molar number of 2/100 to 10/100.   The conductive adhesive according to claim 1 or 2, wherein the polar solvent is a single solvent of diglyme, triglyme, tetraglyme, propylene carbonate, γ-butyrolactone, or ε-caprolactone, or a mixed solvent of two or more. .   The polar solvent is a mixed solvent of at least one of diglyme, triglyme, tetraglyme, propylene carbonate, γ-butyrolactone, and ε-caprolactone, and ethylene carbonate. The electroconductive adhesive material of description. The initial volume resistivity is 10 ² to 10 ⁴ Ω · cm, and the initial adhesive strength according to JIS Z0237 180-degree peeling method is 60 to 610 gf / 25 mm width. The electroconductive pressure-sensitive adhesive material according to any one of claims 1 to 4, which has a volume resistivity and adhesive strength within the above range.