JPH10338779A - Rubber composition and vulcanized rubber composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition, having a low electrical resistance value, excellent in electroconductivity, capable of preventing bleeding, etc., from occurring and excellent in appearance by including an ethylene-olefin-based copolymer rubber and a surface treated filler therein. SOLUTION: This rubber composition is obtained by including (A) 100 pts.wt. ethylene-α-olefin-based copolymer rubber and (B) 10-500 pts.wt. surface treated filler prepared by compounding a compound represented by formula I (Y is a substituted 2-22C aliphatic or aromatic carboxylic acid residue; R1 is H or a 1-15C alkyl; Z is a 2-4C alkylene) J is 1-30; K is 1-4) and/or a compound represented by formula II [R2 and R3 are each a 1-15C alkyl or a 1-15C alkenyl; R4 is H or methyl; (p) is 2-20] with an alkali metallic salt-containing compound and/or an alkaline earth metallic salt-containing compound [e.g. LiClO4 or Ba(ClO4 )2 ] and supporting the resultant composition on a filler (e.g. calcium carbonate or silica).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a rubber composition and a vulcanized rubber composition. More specifically, the present invention relates to a rubber composition containing an ethylene-α-olefin-based copolymer rubber as a rubber component, which has a low electric resistance value, thus has excellent conductivity, and prevents the occurrence of bleed and the like. ,
Therefore, the present invention relates to a rubber composition and a vulcanized rubber composition which are excellent in appearance and can be made white.

[0002]

2. Description of the Related Art Ethylene-α-olefin copolymer rubber represented by ethylene-propylene rubber has weather resistance,
Due to its excellent ozone resistance and heat resistance, it is widely used for various office supplies and electrical products.

[0003] Rubber products used for applications such as various office supply parts and electric product parts are required to have a low electric resistance value, that is, to have excellent conductivity. This is to prevent various failures due to accumulation of static electricity. As a method for increasing the conductivity of rubber products, a method of blending a large amount of carbon black is known. However, the rubber product obtained by this method is inevitably black, which is unsatisfactory from an aesthetic point of view, and it is difficult to impart sufficient conductivity while suppressing contamination of OA paper and the like used for office equipment. Was. Also, Japanese Patent Application Laid-Open No. 2-2450
No. 38 discloses a method using a specific plasticizer. However, this method can provide white rubber, but is insufficient in that sufficient conductivity is imparted while suppressing the occurrence of bleeding and the like.

[0004]

In view of the above situation, an object of the present invention is to provide a rubber composition containing an ethylene-α-olefin-based copolymer rubber as a rubber component and having an electric resistance value. Another object of the present invention is to provide a rubber composition and a vulcanized rubber composition which are low in conductivity, are excellent in conductivity, prevent the occurrence of bleeding and the like, are excellent in appearance, and can be made white.

[0005]

That is, one aspect of the present invention relates to a rubber composition containing the following components (A) and (B). (A): ethylene-α-olefin-based copolymer rubber (B): an alkali metal salt with respect to a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2) -Treated filler obtained by supporting a compound obtained by compounding a compound containing an alkali metal earth salt and / or a compound containing an alkali metal earth on a filler (In the formula (1), Y is a group having 2 to 2 carbon atoms which may have a substituent.
2 represents an aliphatic, alicyclic or aromatic carboxylic acid residue or a carboxylic acid residue of an epoxycyclohexane ring,
R ₁ represents a hydrogen atom or a linear or branched alkyl group having 1 to 15 carbon atoms; Z represents an alkylene group having 2 to 4 carbon atoms; J represents a number of 1 to 30; Represents an integer. In the formula (2), R ₂ and R ₃ represent an alkyl group or an alkenyl group having 1 to 15 carbon atoms, R ₄ represents a hydrogen atom or a methyl group, and p represents an integer of 2 to 20. )

Another aspect of the present invention relates to a vulcanized rubber composition obtained by vulcanizing the above rubber composition.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) of the present invention comprises ethylene-
α-Olefin copolymer rubber.

[0008] Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, and 4-hexene.
Examples thereof include methyl-1-pentene, 1-octene, and 1-decene, and among them, propylene is preferable. Examples of the non-conjugated diene include 1,4-hexadiene,
Chain non-conjugated dienes such as 1,6-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene; cyclohexadiene, dicyclopentadiene , Methyltetrahydroindene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6
Cyclic non-conjugated dienes such as -chloromethyl-5-isopropenyl-2-norbornene; 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2・
2-norbornadiene, 1,3,7-octatriene,
Trienes such as 1,4,9-decatriene are mentioned, among which 5-ethylidene-2-norbornene or 5
-Both ethylidene-2-norbornene and dicyclopentadiene are preferred.

The ratio (molar ratio) of ethylene / α-olefin / non-conjugated diene in component (A) is usually 1 /
(0.1-1) / (0-0.2).

The component (B) of the present invention has the general formula (1)
And / or a mixture of a compound represented by the following general formula (2) and a compound represented by the following general formula (3) are mixed with an alkali metal salt-containing compound and / or an alkali metal earth salt. It is a surface-treated filler obtained by supporting a blend obtained by blending a content compound with a filler.

As the filler, calcium carbonate, silica, talc, clay, magnesium carbonate, zeolite,
Examples thereof include aluminum sulfate, barium sulfate, mica, aluminum hydroxide, zinc oxide, and titanium white, and are preferably calcium carbonate and silica. The filler is preferably in a powder form. In addition, silica as a filler has a DBA (dibutylamine) adsorption amount of 100 to 4
00 mmol / kg and a BET specific surface area of 50 to 3
It is preferably a powder having a water content of 00 m ² / g and a pH of 5 to 12.

A preferred specific example of the compound represented by the general formula (1) is bis [2- (2-butoxyethoxy)
Ethyl] adipate, bis (2-butoxyethyl) phthalate, diester compounds derived from polyethylene glycol having a molecular weight of 100 to 2,000 and adipic acid, and diester compounds derived from polyethylene glycol having a molecular weight of 100 to 2,000 and phthalic acid. it can.

Preferred examples of the compound represented by the general formula (2) include trioxyethylene glycol dioctoate, tetraoxyethylene glycol dioctoate and heptaoxyethylene glycol dioctoate.

In the present invention, a compound represented by the following general formula (3) is used in combination with the compound represented by the above general formula (1) and / or the compound represented by the above general formula (2). May be.

[0015]

(Wherein, L and M represent 1 or 2, N and O represent an integer of 1 to 3, X represents an alkylene group having 2 to 4 carbon atoms, and R ₄ and R ₅ represent a carbon number. Represents 1 to 8 linear or branched alkyl groups.)

Preferred specific examples of the compound represented by the general formula (3) include bis [2- (2-butoxyethoxy)
Ethyl) thiodipropionate and bis (2-butoxyethyl) thiodipropionate can be mentioned.

As the cation site of the alkali metal salt or alkaline earth metal salt of the component (B), Li, Na, K,
Mg, Ba, Ca, etc. can be mentioned, and Cl, Br, I, BF ₄ , PF ₄ , Cl
O ₄ , NO ₃ , CO _{3 and the} like can be mentioned.

The compound containing an alkali metal salt or the compound containing an alkali metal earth salt includes LiClO ₄ , Ba (C
lO ₄ ) ₂ , LiI and MgCO ₃ are preferred.

The mixture of the compound represented by the general formula (1) and / or the compound represented by the general formula (2) and the compound represented by the general formula (3) is added to a compound containing an alkali metal salt and / or Alternatively, when the compound containing an alkali metal earth salt is compounded, the compounding ratio of the compound represented by the general formula (1) and the compound represented by the general formula (2) is 100 parts by weight of the compound represented by the general formula (2). The total amount of the compound and the compound containing an alkali metal earth salt is preferably 0.01 to 30 parts by weight, more preferably 0.1 to 20 parts by weight. When the total amount of the alkali metal salt-containing compound and the alkali metal earth salt-containing compound is too small, the electric resistance value does not sufficiently decrease, and the antistatic effect may be poor. The effect of lowering the electric resistance value with respect to the additional amount of the metal salt-containing compound and the alkali metal earth salt-containing compound may level off and become uneconomical.

In order to obtain the blend in the component (B), the compound represented by the general formula (1) and / or the compound represented by the general formula (2) is added to the compound containing an alkali metal salt and / or the compound represented by the general formula (2).
Alternatively, a compound containing an alkali metal earth salt may be blended.

The weight ratio of the compound / filler in the component (B) is preferably from 60/40 to 5/95, and more preferably from 55/45 to 10/90. If the ratio is too small, the conductivity may be insufficient, while if the ratio is too large, the compound cannot be supported on the surface of the filler, and the compound may be formed on the surface of the obtained vulcanized rubber. May bleed. When two or more fillers are used in combination, the weight of the filler is based on the total amount of all the fillers.

As a method for obtaining the surface-treated filler which is the component (B) of the present invention, for example, a Henschel mixer, a tumbling drum, a super mixer, a ball mill, an atomizer or the like is used to add the above-mentioned compound to the filler as a carrier. May be carried.

In the rubber composition of the present invention, the content of the component (B) per 100 parts by weight of the component (A) is from 10 to 5%.
00 parts by weight, more preferably 10 parts by weight.
４００400 parts by weight. If the amount of the component (B) is too small, the conductivity may be insufficient. On the other hand, if the amount of the component (B) is too large, the compound viscosity may increase and the processability may be poor. In the present invention, a rubber other than the ethylene-α-olefin-based copolymer rubber as the component (A) may be used in combination within a range that does not impair the object of the present invention. A) The amounts of the components are based on the total amount including the amounts of all rubbers.

The greatest feature of the present invention is that the component (B) is used. Without using the present invention, when only the filler is used, the electric resistance cannot be sufficiently reduced. When the compound of the present invention is used without being carried on a filler, bleeding occurs and the appearance of the vulcanized rubber product is inferior.

The method for obtaining the rubber composition of the present invention includes:
For example, the following method can be used. That is, the components (A) and (B) of the present invention, and, if necessary, a reinforcing material, a softening agent such as process oil, an activator such as stearic acid, a vulcanization accelerating aid such as zinc oxide, A compound is obtained by kneading a white filler (extending material) such as calcium using a Banbury mixer, a kneader or the like. Next, a vulcanizing agent, a vulcanization accelerator, and the like are kneaded with the compound using an open roll, a kneader, or the like to obtain a rubber composition before vulcanization.
Here, sulfur and various organic peroxides are used as the vulcanizing agent. The rubber composition before vulcanization is vulcanized under normal conditions.

The rubber composition and the vulcanized rubber composition of the present invention have the above-mentioned characteristics, and are used for various office supplies, electric products, and the like, for example, rolls, belts, and sealing materials for electric machines. , Can be widely used in the fields of antistatic mats, conductive sheets and the like.

[0028]

Next, the present invention will be described by way of examples. Examples 1 to 6 and Comparative Examples 1 to 5 1 part by weight of stearic acid, 5 parts by weight of zinc white, 15 parts by weight of nip seal VN3 (silica), Diana PW-90 (process oil) 10 parts by weight and 10 parts by weight of Taipaque R550 (titanium white) were kneaded using a Banbury mixer to form a compound. Next, 1.0 part by weight of soscinol BZ (vulcanization accelerator) and sosinol TT (vulcanization accelerator) were added to the compound.
0.5 parts by weight, Succinol TRA (vulcanization accelerator)
5 parts by weight, 1.0 part by weight of succinol M (vulcanization accelerator) and 1.0 part by weight of sulfur were added and kneaded using an open roll to obtain a rubber composition. The obtained rubber composition was press-vulcanized at 160 ° C. for 15 minutes to obtain a vulcanized rubber composition. The vulcanized rubber composition was evaluated as follows.

(1) Conductivity: The volume resistivity was measured at an applied voltage of 500 V in accordance with JIS K 6911.

(2) Surface bleed: The obtained vulcanized rubber sheet was allowed to stand at room temperature for one week, and the presence or absence of bleed on the surface was visually observed, and evaluated by ○ (good) and × (poor).

Examples 7 to 8 and Comparative Examples 6 to 7 The composition shown in Table 2 and 1 part by weight of stearic acid, 5 parts by weight of zinc white, 30 parts by weight of nip seal VN3 (silica), and Diana PW-90 ( Process oil) 10 parts by weight, Taipaque R550 (titanium white) 30 parts by weight, PEG 4000
A compound was prepared by kneading 2 parts by weight of (polyethylene glycol) and 1 part by weight of a silane coupling agent (A-172) using a Banbury mixer. Next, DCP (dicumyl peroxide) was added to the compound.
A rubber composition was obtained by adding and kneading 3.5 parts by weight, 2 parts by weight of TAIC (triallyl isocyanurate) and 0.4 part by weight of sulfur. 170 ° C. of the obtained rubber composition
Press vulcanization was performed under conditions of × 20 minutes to obtain a vulcanized rubber composition. The same evaluation as described above was performed for the vulcanized rubber composition.

The following can be seen from the results. All examples satisfying the conditions of the present invention show satisfactory results in all evaluation items. On the other hand, Comparative Example 1, Comparative Example 6 and Comparative Example 7, in which the component (B) of the present invention was not used and the compound was not used, and Comparative Example 2 in which a relatively small amount of a conductive plasticizer was used, had poor conductivity. . In Comparative Example 3 using a large amount of the compound without using the component (B) of the present invention, surface bleeding occurred.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

* 1 Formulation A-1: Ethylene-propylene-5-ethylidene-2-
Norbornene copolymer rubber (ethylene ratio = 80% by weight, iodine value = 15, Mooney viscosity at 100 ° C. =
35) A-2: Ethylene-propylene-dicyclopentadiene copolymer rubber (ethylene ratio = 65% by weight, iodine value =
8, Mooney viscosity at 100 ° C. = 55) B-1: weight ratio of calcium carbonate / compound-1 = 75 /
25 supported product B-2: supported product of silica / compound-1 weight ratio = 75/25 B-3: supported product of calcium carbonate / silica / compound-2 weight ratio = 49/21/30 compound-1 : Bis [2- (2-butoxyethoxy) ethyl] adipate / bis [2- (2-butoxyethoxy)
Ethyl) thiodipropionate / LiClO ₄ (weight ratio) = 49/1/1 mixture Compound-2: Ester obtained from 1 mol of adipic acid and 2 mol of polyethylene glycol having an average molecular weight of 600 /
LiClO ₄ (weight ratio) = 20/1 mixture CaCO ₃ : powdered calcium carbonate Common formulation: In Table 1, in addition to the components described in Table 1,
As a common formulation, stearic acid 1 part by weight, zinc white 5 parts by weight, nip seal VN3 (silica) 15 parts by weight, Diana PW-90 (process oil) 10 parts by weight, Taipaque R550 (titanium white) 10 parts by weight, soscinol BZ
(Vulcanization accelerator) 1.0 part by weight, succinol TT (vulcanization accelerator) 0.5 part by weight, succinol TRA (vulcanization accelerator) 0.5 part by weight, succinol M (vulcanization accelerator)
0 parts by weight and 1.0 parts by weight of sulfur were used. In Table 2, in addition to the components described in Table 2, 1 part by weight of stearic acid, 5 parts by weight of zinc white, nip seal VN3
(Silica) 30 parts by weight, Diana PW-90 (process oil) 10 parts by weight, Taipaque R550 (titanium white)
30 parts by weight, PEG 4000 (polyethylene glycol) 2 parts by weight, silane coupling agent (A-172) 1
Parts by weight, 3.5 parts by weight of DCP (dicumyl peroxide), 2 parts by weight of TAIC (triallyl isocyanurate) and 0.4 parts by weight of sulfur were used.

[0037]

As described above, according to the present invention, there is provided a rubber composition containing an ethylene-α-olefin copolymer rubber as a rubber component, which has a low electric resistance value, and therefore has excellent conductivity and bleed. Thus, it was possible to provide a rubber composition and a vulcanized rubber composition which are capable of preventing the occurrence of such a phenomenon and having an excellent appearance and being white.

Claims (11)

[Claims] 1. A rubber composition containing the following components (A) and (B). (A): ethylene-α-olefin-based copolymer rubber (B): an alkali metal salt with respect to a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2) -Treated filler obtained by supporting a compound obtained by compounding a compound containing an alkali metal earth salt and / or a compound containing an alkali metal earth on a filler (In the formula (1), Y is a group having 2 to 2 carbon atoms which may have a substituent.
2 represents an aliphatic, alicyclic or aromatic carboxylic acid residue or a carboxylic acid residue of an epoxycyclohexane ring,
R ₁ represents a hydrogen atom or a linear or branched alkyl group having 1 to 15 carbon atoms; Z represents an alkylene group having 2 to 4 carbon atoms; J represents a number of 1 to 30; Represents an integer. In the formula (2), R ₂ and R ₃ represent an alkyl group or an alkenyl group having 1 to 15 carbon atoms, R ₄ represents a hydrogen atom or a methyl group, and p represents an integer of 2 to 20. ) 2. The rubber composition according to claim 1, wherein the α-olefin of the component (A) is propylene. 3. The rubber composition according to claim 1, wherein the filler of the component (B) is calcium carbonate or silica or a mixture thereof. 4. The rubber composition according to claim 1, wherein the compound represented by the general formula (1) is bis [2- (2-butoxyethoxy) ethyl] adipate or bis (2-butoxyethyl) phthalate. 5. The compound represented by the general formula (1) is a diester compound derived from polyethylene glycol having a molecular weight of 100 to 2,000 and adipic acid or having a molecular weight of 100.
The rubber composition according to claim 1, which is a diester compound derived from polyethylene glycol and phthalic acid. 6. The rubber composition according to claim 1, wherein the compound represented by the general formula (2) is trioxyethylene glycol dioctoate, tetraoxyethylene glycol dioctoate or heptaoxyethylene glycol dioctoate. . 7. The cation site of the alkali metal salt or alkaline earth metal salt of the component (B) is Li, Na, K, Mg,
Ba or Ca, wherein the anion site is Cl, Br, I,
_{BF 4, PF 4, ClO 4} , NO 3 or CO ₃ in a claim 1 rubber composition. 8. The method according to claim 1, wherein the compound containing an alkali metal salt or the compound containing an alkali metal earth salt is LiClO ₄ , Ba (ClO
₄ ) The rubber composition according to claim 1, which is ₂ , LiI or MgCO ₃ . 9. The rubber composition according to claim 1, wherein the weight ratio of compound / filler in component (B) is from 60/40 to 5/95. 10. The rubber composition according to claim 1, wherein the content of the component (B) is 10 to 500 parts by weight per 100 parts by weight of the component (A). 11. A vulcanized rubber composition obtained by vulcanizing the rubber composition according to claim 1.