JP2987970B2 - Conductive urethane elastomer forming composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for forming a conductive urethane elastomer, and more particularly, a conductive urethane elastomer formed exhibits excellent durability as a connector sheet for a connector element, a board inspection element and the like. The present invention relates to a conductive urethane elastomer-forming composition.

[0002]

2. Description of the Related Art A conductive sheet is effectively used for various purposes as a member for achieving electrical connection. Conventionally, a conductive sheet having a structure in which metal particles are uniformly dispersed in an insulating polymer elastic body (see JP-A-51-93393), a conductive magnetic material in the insulating polymer elastic body, Known are those having a structure in which particles are dispersed at an uneven density (see JP-A-53-147772 and JP-A-54-146873).
Various silicone rubbers are used as the insulating polymer elastic body.

[0003]

However, a conventional conductive sheet using an insulating polymer elastic body increases the electrical resistance with the number of times of use, and the conductive state becomes unstable, so that the connector element is not used. In addition, there is a problem that the durability as a connector sheet for a board inspection element or the like is low.

An object of the present invention is to provide a conductive urethane elastomer-forming composition capable of forming a conductive urethane elastomer having excellent durability as a connector sheet for a connector element, a board inspection element, and the like. .

[0005]

The conductive urethane elastomer-forming composition of the present invention comprises (a) a polyol compound in which at least 50% by weight is a polycarbonate diol and a polyisocyanate compound, and a urethane-forming reaction. 100 parts by weight of a urethane elastomer-forming component forming a urethane elastomer, (b) conductive particles 30 to 10
It is characterized in that 00 parts by weight are dispersed.

Hereinafter, the present invention will be described specifically.
The composition of the present invention comprises (a) a urethane elastomer-forming component (hereinafter also referred to as “component (a)”) containing a polyol compound in which at least 50% by weight is a polycarbonate diol and a polyisocyanate compound, and The essential component is (a) the conductive particles dispersed in the component (b).

[0007] Component (a) The component (a) is a urethane elastomer-forming component comprising a polyol compound and a polyisocyanate compound. The component (a) is liquid under a temperature condition of room temperature to 80 ° C. or lower, and can uniformly mix conductive particles described later.

The polyol compound used as the component (a) is at least 50% by weight of a polycarbonate diol. Other polyol compounds include polyester polyols, polyether polyols, polybutadiene polyols, and castor oil polyols. And silicone-based polyols. The polycarbonate diol is a linear polyol compound having an OH group at both ends obtained by reacting an alkanediol and a carbonate compound [structural formula: HO- [RO-CO-
O] _n -R-OH (R: alkylene group). As the alkanediol, propylene glycol, dipropylene glycol, ethylene glycol, diethylene glycol, 1,4-butanediol, 1,5-heptanediol, 1,6-hexanediol and the like, preferably 1,6-hexanediol is used. You. As the carbonate compound, ethylene carbonate, diethyl carbonate,
Preferably ethylene carbonate, such as diphenyl carbonate, is used. The molecular weight of the polycarbonate diol is usually from 1,000 to 4,000, preferably from 2,000 to 40.
00. Examples of the polyester-based polyol include polycarbonate polyols other than the polycarbonate diol, polymethylpentanediol adipate-based polyol, polymethylvalerolactone-based polyol, polycaprolactone-based polyol, and polybutanediol-adipate-based polyol. Polyether polyols include polypropylene glycol,
Examples thereof include polytetramethylene glycol and modified products thereof. Examples of the polybutadiene-based polyol include polybutadiene diol and hydrogenated polybutadiene diol. Examples of the silicone polyol include silicone diol and silicone triol. Further, as a polyol compound, 1,4-butanediol, 1,6-hexanediol,
Polyhydric alcohols such as 1,5-pentanediol, trimethylolpropane and neopentyl glycol can also be used. Among these, as other polyol compounds, polyester-based polyols include polymethylpentanediol adipate-based polyols and polymethylvalerolactone-based polyols, and polyether-based polyols include polytetramethylene glycol and polytetramethylene glycol. A modified product with methylene glycol is preferable, and trimethylolpropane is preferable as a polyhydric alcohol. These compounds can use not only one kind but two or more kinds as the polyol compound according to the present invention. The component (a) is at least 50% by weight of a polycarbonate diol. 50% by weight
If it is less than 1, a conductive urethane elastomer having good durability cannot be obtained. The polyol compound used is 2
It is preferable to contain not only a functional polyol compound but also a trifunctional or higher functional polyol compound such as trimethylolpropane, trimethylolethane, hexanetriol, and pentaerythritol. The molar ratio of the trifunctional or higher functional polyol compound to the bifunctional polyol compound is preferably 0.5 / 0.5 to 0.9 / 0.1, and more preferably 0.7 / 0.3 to 0.9 / 0.1.

The polyisocyanate compound used in the present invention includes tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, dianisidine isocyanate, diphenyl ether diisocyanate, vitriylene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, hexamethylene diisocyanate. , Isophorone diisocyanate, meta-xylylene diisocyanate, and modified products thereof. Of these, tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate, isophorone diisocyanate, and modified products thereof can be preferably used. The polyisocyanate compound used is not only a bifunctional polyisocyanate compound, but also polymeric diphenylmethane diisocyanate, triphenylmethane triisocyanate, triisocyanate phenyl thiophosphate, tolylene diisocyanate trimethylol propane adduct, tolylene diisocyanate isocyanurate, It preferably contains a tri- or higher functional polyisocyanate compound such as a methylene diisocyanate-buret compound, in which case a good urethane elastomer can be formed after curing. The molar ratio of the trifunctional or higher polyisocyanate compound to the bifunctional polyisocyanate compound is preferably 0.5 / 0.5 to 0.9 / 0.1, and more preferably 0.7 / 0.3 to 0.9 / 0.1.

[0010] The polyol compound and the polyisocyanate compound may be mixed as they are to form the component (a). Further, a part of the polyol compound and a polyisocyanate compound containing an isocyanate group in an equivalent amount or more with respect to a part of the hydroxyl groups of the polyol compound are reacted to synthesize a urethane prepolymer. The component (a) may be constituted by mixing a polyol compound. The latter case is preferred in that a urethane elastomer having excellent polymer properties such as tensile strength is formed. The entire polyol compound and polyisocyanate compound contain the hydroxyl group of the polyol compound and the isocyanate group of the polyisocyanate compound in an equivalent ratio, usually from 1 / 1.0 to 1 / 1.3.

The component (a) includes, if necessary, a catalyst such as dibutyltin laurate, triethylamine and triethylenediamine, and an amine curing agent such as methylene bis (2-chloroaniline) and polytetramethylene oxide di-p-aminobenzoate. , A filler such as silica and hydrophobic silica, a castor oil derivative, a thixotropic regulator such as basic calcium sulfonate, and a flame retardant auxiliary such as a phosphorus compound.

The viscosity of the component (a) at a temperature of 25 ° C. is as follows:
Preferably, the strain rate is in the range of 10 ⁴ to 10 ⁷ centipoise at a strain rate of 10 ^-1 sec ^-1 . If the viscosity is too low, sedimentation of the conductive particles tends to occur. On the other hand, when the viscosity is excessive, the conductive particles are difficult to disperse, and the defoaming treatment of the composition tends to be difficult. The viscosity can be adjusted by adding a filler or a thixotropic agent, and it is also possible to use means for diluting with a solvent such as toluene or xylene.

The component (a) forms a urethane elastomer by a urethane-forming reaction, and the hardness of the formed urethane elastomer measured by a JISA type hardness tester is 15 to 70.
Is preferably, and more preferably 20 to 60. If the hardness is less than 15, there may be cases where stable conductivity cannot be exhibited during use, while if it exceeds 70, the electrical resistance during use becomes excessive, so that the sheet is applied as a conductive sheet. This can be difficult.

Conductive Particles Conductive particles include, for example, particles of magnetic metals such as nickel, iron, and cobalt, particles of alloys of these metals, gold, silver, and palladium on the surfaces of particles of magnetic metals or alloys. And those obtained by plating non-magnetic metal particles, glass beads, or other inorganic particles or polymer particles with a conductive magnetic material such as nickel or cobalt. Of these,
From the viewpoint of reducing the manufacturing cost, in particular, conductive particles composed of nickel, iron or an alloy thereof are preferable, and the conductive particles further subjected to gold plating are small in terms of electrical characteristics such as low contact resistance. preferable.

The particle size of the conductive particles is preferably from 3 to 200 μm, particularly preferably from 10 to 100 μm.
By using the conductive particles having a particle diameter in such a range, in the finally obtained conductive urethane elastomer, sufficient electric contact between the conductive particles is achieved at the time of use, and the conductive portion is miniaturized. Can be handled.

The amount of the conductive particles used is 30 to 1,000 parts by weight based on 100 parts by weight of the component (a). If the amount used is less than 30 parts by weight, the conductive urethane elastomer finally obtained does not have a sufficient conductive path even at the time of use, and does not have a good switching function due to an excessively high electric resistance value. On the other hand, if the used amount exceeds 1000 parts by weight, the obtained conductive urethane elastomer becomes fragile, and it becomes difficult to use.

Production Method The conductive urethane elastomer-forming composition of the present invention comprises:
It can be produced by mixing the component (a) and the conductive particles and stirring the mixture.

Molding Method The conductive urethane elastomer-forming composition of the present invention is cured by a urethanization reaction to form a conductive urethane elastomer having rubbery elasticity. Actually, after the composition of the present invention is subjected to a defoaming treatment, a molding process may be performed. As a method for producing a sheet of conductive urethane elastomer, the composition of the present invention is injected into a mold having a magnetic pole plate, and a magnetic field treatment is performed to arrange the conductive particles in the thickness direction. A method of forming a sheet-shaped conductive urethane elastomer by heat-curing the composition in, the composition of the present invention is printed on a substrate having a lead electrode portion by a screen printing method or the like, and then subjected to a magnetic field treatment. After arranging the conductive particles in the thickness direction and thermally curing the composition,
A method of forming a conductive portion integrally formed on the substrate may be used.

When the magnetic field treatment is performed, the use of a magnetic pole plate having portions having different magnetic field strengths causes unevenness of conductive particles in the cured urethane elastomer sheet, so that the conductive portion and the insulating portion are separated from each other. Existing anisotropically conductive urethane elastomer sheets can also be formed. Here, the conductive portion may be pressurized conductive in which the conductive portion is formed by reducing the resistance value by being pressed in the thickness direction.

[0020]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1 <Synthesis of Main Agent> As shown in Table 1, polycarbonate diol "DN-986" (manufactured by Nippon Polyurethane Industry Co., Ltd.) 35
g, modified polytetramethylene glycol “PTGL-40”
00 "(manufactured by Hodogaya Chemical Co., Ltd.), 20 g of polymeric diphenylmethane diisocyanate" Millionate MR-200 "
13.5 g (manufactured by Nippon Polyurethane Industry Co., Ltd.) and modified diphenylmethane diisocyanate "Sumidur PF"
(Sumitomo Bayer Urethane Co., Ltd.)
The mixture was reacted by heating and stirring at 5 ° C. for 5 hours to synthesize a viscous liquid prepolymer. This is designated as “base agent P-1”.

<Preparation of Curing Agent> As shown in Table 1, 85 g of polycarbonate diol "Nipporan 982R" (manufactured by Nippon Polyurethane Industry Co., Ltd.) and 15 g of polyester triol "Kurapol P-3000" (manufactured by Kuraray) were mixed. Thus, a mixture of polyol compounds was prepared. This is designated as "curing agent H-1".

<Preparation of Component (a)> As shown in Table 1,
The main agent P-1 and the curing agent H-1 were added in a weight ratio of 1.0 / 2.0.
[OH group / NCO group = 1.0 / 1.05 (equivalent)] was mixed to prepare the component (a). This is referred to as “Component A-
1 ".

<Preparation of Composition> As shown in Table 2, 100 parts by weight of component A-1 and 400 parts by weight of conductive particles made of nickel having an average particle diameter of 40 μm (hereinafter referred to as “component B-1”). And the components were mixed to prepare a composition of the present invention. This is designated as “composition C-1”.

<Formation of connector layer> Each width is 0.15 m
m, a connector layer having a flat outer surface as a whole is formed on the lead electrode area of the circuit board having a total of 240 lead electrodes formed by applying gold plating to copper having an electrode pitch of 0.25 mm as follows. The device was manufactured. After subjecting the composition C-1 to a defoaming treatment under reduced pressure, the composition C-1 is applied on a lead electrode by a screen printing method to form a conductive portion of a connector layer. Diluent
It was applied by spin coating to a region other than the lead electrode region to form an insulating portion of the connector layer. As shown in FIG. 1, a magnetic pole plate 30 composed of a ferromagnetic material portion M and a non-ferromagnetic material portion N and having a flat lower surface is used. 0.3 mm thick connector layer integrated with the circuit board 10 by allowing it to stand at 100 ° C for 4 hours while applying a parallel magnetic field with the upper mold 31 and the lower mold 32 in contact with the surface of Was formed. The width of the ferromagnetic portion M in the magnetic pole plate 30 used and the center-to-center distance (pitch) between adjacent ones are the same as the width and the electrode pitch of the lead electrode layer 13 of the circuit board 10. The conditions are the same in the following examples and comparative examples.

Example 2 <Preparation of component (a)>
The main agent P-2 is synthesized by performing the same operation as described above, and the curing agent H-
2 was prepared and further mixed at the weight ratio shown in Table 1 to obtain component A-
2 was prepared.

<Preparation of Composition> According to the formulation shown in Table 2,
The component B-1 was mixed with the component A-2 in the same manner as in Example 1 to prepare a composition C-2 of the present invention.

<Formation of Connector Layer> A conductive portion of a connector layer is formed by using composition C-2 instead of composition C-1, and a connector layer is formed by using component A-2 instead of component A-1. A connector layer having a thickness of 0.3 mm integrated with the circuit board was formed in the same manner as in Example 1 except that the insulating portion was formed.

Example 3 <Preparation of composition> As shown in Table 2, instead of the component B-1, nickel-plated nickel (40 g of gold per 1 kg of nickel) having an average particle size of 40 μm was used. Example 1 except that conductive particles (hereinafter referred to as “component B-2”) were used.
The composition C-3 of the present invention was prepared in the same manner as in the above.

<Formation of Connector Layer> A thickness integrated with a circuit board in the same manner as in Example 1 except that the conductive portion of the connector layer was formed using composition C-3 instead of composition C-1. A connector layer having a thickness of 0.3 mm was formed.

Comparative Example 1 <Preparation of Composition> 10 g of a curing agent "CAT1600" (manufactured by Shin-Etsu Silicone) was added to 100 g of room temperature-curable silicone rubber compound "KE-1600" (manufactured by Shin-Etsu Silicone) and mixed. . This mixture is referred to as “component a-1”. Table 3
As shown in the above, component B-1 was mixed with component a-1 in the same manner as in Example 1 to prepare composition c-1.

<Formation of Connector Layer> After subjecting composition c-1 to defoaming under reduced pressure, this composition c-1 is applied on a lead electrode by a screen printing method to form a conductive portion of the connector layer. A diluted solution of the component a-1 "RTV Thinner" (manufactured by Shin-Etsu Silicone Co., Ltd.) was applied to regions other than the lead electrode region by spin coating to form insulating portions of the connector layer. Thereafter, the same operation as in Example 1 was performed to form a connector layer having a thickness of 0.3 mm integrated with the circuit board.

Comparative Examples 2 and 3 <Preparation of Component (a)>
By performing the same operation as described above, the main agents p-2 and p-3 were synthesized, and curing agents h-2 and h-3 were prepared. Components a-2 and a-3 were prepared by mixing at the respective weight ratios shown in Table 1.

<Preparation of Composition> According to the formulation shown in Table 3,
Components c-2 and c-3 were prepared by mixing component B-1 with each of components a-2 and a-3 in the same manner as in Example 1.

<Formation of Connector Layer> A conductive portion of the connector layer is formed by using each of the compositions c-2 and c-3 instead of the composition C-1, and a component a is used instead of the component A-1.
The same operation as in Example 1 was performed except that an insulating portion of the connector layer was formed using each of -2 and a-3 to form a connector layer having a thickness of 0.3 mm integrated with the circuit board.

Comparative Examples 4 and 5 <Preparation of Composition> Composition c-4 and composition c-4 were prepared in the same manner as in Example 3 except that the amount of component B-2 was changed according to the formulation shown in Table 3. c-5 was prepared.

<Formation of Connector Layer> A circuit was formed in the same manner as in Example 1 except that the conductive portion of the connector layer was formed using each of compositions c-4 and c-5 instead of composition C-1. A connector layer having a thickness of 0.3 mm integrated with the substrate was formed.

Examples 4 to 5 <Preparation of Composition> The same operations as in Examples 1 and 2 were carried out except that the amount of component B-1 was changed to 150 parts by weight according to the formulation shown in Table 4. The composition of the invention C-
4 to C-5 were prepared.

<Manufacture of Conductive Sheet> After subjecting each of the compositions C-4 to C-5 to a defoaming treatment under reduced pressure, each of the compositions C-4 to C-5 was treated as shown in FIG. A pole plate comprising a ferromagnetic portion M and a non-ferromagnetic portion N, wherein the non-ferromagnetic portion N protrudes 0.03 mm from the ferromagnetic portion M.
35, and in this state, as shown in FIG.
And the lower mold 32 is left for 4 hours at 100 ° C. while applying a parallel magnetic field to the magnetic pole plate 35 to be cured, and the conductive part 23 having a thickness of 0.3 mm in which the conductive particles E are arranged in the thickness direction; An anisotropic conductive sheet comprising an insulating portion 24 having a thickness of 0.24 mm and having a small probability of existence of the conductive particles E was produced.

Example 6 <Preparation of composition> The composition of the present invention was prepared in the same manner as in Example 3 except that the amount of component B-2 was changed to 150 parts by weight according to the formulation shown in Table 4. Compound C-6 was prepared.

<Production of Conductive Sheet> The thickness of the conductive portion was 0.3 mm and the thickness of the insulating portion was 0.24 in the same manner as in Example 4 except that the composition C-6 was used instead of the composition C-4. mm of an anisotropic conductive sheet was manufactured.

Comparative Examples 6 to 8 <Preparation of Composition> The compositions were prepared in the same manner as in Comparative Examples 1 to 3 except that the amount of the component B-1 was changed to 150 parts by weight according to the formulation shown in Table 5. Compounds c-6 to c-8 were prepared.

<Production of Conductive Sheet> A conductive part having a thickness of 0.3 mm was prepared in the same manner as in Example 4 except that each of the compositions c-6 to c-8 was used instead of the composition C-4. An anisotropic conductive sheet having a thickness of 0.24 mm of the insulating portion was manufactured.

Comparative Examples 9 to 10 According to the formulation shown in Table 5, composition c was used in place of composition C-4.
The thickness of the conductive part was 0.3 mm and the thickness of the insulating part was 0.24 in the same manner as in Example 4 except that each of -4 and c-5 was used.
mm of an anisotropic conductive sheet was manufactured.

<Evaluation of Connector Layer and Conductive Sheet> A circuit board device having a connector layer integrated with the circuit boards obtained in Examples 1 to 5 and Comparative Examples 1 to 5 is as follows. And the durability was evaluated. Measure the electrical resistance (initial value) when the connector layer is pressurized so that a 25% strain is generated.
Repeated 0000 times, the change in electric resistance was measured. In addition, after the conductive sheets obtained in Examples 4 to 6 and Comparative Examples 6 to 10 were aligned with the circuit board, the durability of the conductive sheets was evaluated in the same manner as described above. Table 2
Table 5 shows the average value of the initial resistance values and the average value of the resistance values after 30,000 pressurization histories. The hardness of the urethane elastomer sheet shown in Table 1 was obtained by the following method. <Measurement of hardness of urethane elastomer after curing> The hardness was measured by mixing a main component and a curing agent, defoaming under reduced pressure, and heat-curing to prepare a urethane elastomer sheet having a thickness of 13 to 15 mm. According to the test method, the test was performed using a spring type hardness tester A type.

[0046]

[Table 1]

In Table 1, the following polyol compounds and polyisocyanate compounds constituting the main component and the following polyol compounds constituting the curing agent component were used. Further, dibutyltin laurate was used as a urethanization reaction catalyst, and silica fine powder "Aerosil" (manufactured by Nippon Aerosil Co., Ltd.) was used as a filler. [Polyol compound] PO-1: polycarbonate diol "DN-986"
PO-2: Modified polytetramethylene glycol "PTG"
L-4000 "(Hodogaya Chemical Industry Co., Ltd.) PO-3: Silicone diol" KF6003 "(Shin-Etsu Silicone Co., Ltd.) PO-4: Polycarbonate diol" Nipporan 982 "
R "(manufactured by Nippon Polyurethane Co., Ltd.) PO-5: Polyester triol" Kurapol P-30 "
00 "(Kuraray) PO-6: Trimethylolpropane (Mitsubishi Gas Chemical) PO-7:" DK-08-779 "(Dow Corning) PO-8: Polyester diol" Kurapol P1010 "
(Kuraray) [Polyisocyanate compound] PI-1: Tolylene diisocyanate (Mitsui Toatsu Chemicals) PI-2: Polymeric diphenylmethane diisocyanate "Millionate MR-200" (Nippon Polyurethane) PI-3: Modified diphenylmethane Diisocyanate "Sumidur PF" (Sumitomo Bayer Urethane Co., Ltd.)

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

[Table 4]

[0051]

[Table 5]

In Tables 3 and 5, * 1 indicates that the connector layer was peeled off from the circuit board in the middle and a positional shift between the connector layer and the circuit board occurred, and * 2 was a conductive portion of the connector layer in the middle. Indicates that it was damaged.

Examples 1 to 3 and Comparative Examples 1 to 5
This is an example in which a connector layer integrated with a circuit board is formed. It is understood that the compositions of these examples have good adhesion to the epoxy substrate and exhibit stable conductivity even during the durability test.

On the other hand, a conventional silicone rubber composition a-1
In Comparative Example 1, the connector layer was poor in adhesion to the circuit board, and the connector layer was peeled off from the circuit board during the test, resulting in displacement between the two. In Comparative Example 2, the contact of the conductive particles was insufficient, and a high resistance value was exhibited in the durability test. In Comparative Example 3, stable conductivity could not be maintained. In Comparative Example 4, since the amount of the conductive particles used was too small, the formation of the conductive path was insufficient and the resistance value was high even in the durability test, whereas in Comparative Example 5, the amount of the conductive particles used was excessive. Therefore, the strength of the connector layer is insufficient, so that it cannot withstand a durability test, and none of them functions suitably as a connector layer.

Examples 4 to 6 and Comparative Examples 6 to 10
This is an example of manufacturing a conductive sheet. In Comparative Examples 6 to 10, since the conductive sheet and the circuit board were not integrated,
A time-dependent increase in the resistance value was observed due to the positional deviation between the two, which occurred each time the durability test was performed, and none of them suitably functioned as the connector layer. On the other hand, it is understood that Examples 4 to 6 using the composition of this Example still show stable durability.

[0056]

According to the present invention, by setting the composition of the component (a), the hardness of the urethane elastomer to be formed, and the amount of the conductive particles (b) in a specific range, it is possible to obtain a durable conductive material. A urethane elastomer can be obtained. Further, since the urethane elastomer has high adhesiveness to an adherend, an integrated conductive layer is formed on the circuit board, and an element having higher reliability in electrical connection can be obtained. Therefore, the conductive urethane elastomer-forming composition of the present invention can be suitably used for the production of a board inspection element requiring durability, or a connector element having a large number of insertions / removals, and the like. It is also suitable for manufacturing.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view showing a state where a connector layer is directly formed on a circuit board and a parallel magnetic field is applied.

FIG. 2 is an explanatory sectional view showing a state when a conductive composition is injected between magnetic pole plates.

FIG. 3 is an explanatory sectional view showing that a conductive composition and an insulating portion of a connector layer are formed by applying a parallel magnetic field after injecting a conductive composition between pole plates.

[Explanation of symbols]

 10 Circuit board 13 Lead electrode layer 20 Connector layer 21 Conducting part 22 Insulating part 23 Conducting part 24 Insulating part 30 Magnetic pole plate 31 Upper die 32 Lower die 35 Magnetic pole plate M Ferromagnetic material part N Non-magnetic material part E Conductive particles

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-6255 (JP, A) JP-A-62-95342 (JP, A) JP-A-62-179541 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) C08G 18/44 C08K 3/08 C08L 75/04

Claims (1)

(57) [Claims] (1) 100 parts by weight of a urethane elastomer-forming component which contains a polyol compound in which 50% by weight or more is a polycarbonate diol and a polyisocyanate compound, and forms a urethane elastomer by a urethanization reaction; (3) A conductive urethane elastomer-forming composition, wherein 30 to 1000 parts by weight of conductive particles are dispersed.