JPH09296072A - Molding containing high-electrical-resistance carbon black - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a highly reinforced high-electrical-resistance molding by molding a composition comprising a specified matrixforming substance (hereinbelow referred to as M) and silica-surfacetreated carbon black (hereinbelow referred to as C) surface-coated with a specified amount of silica. SOLUTION: Examplcs of component M used include a member selected among vulcanizable rubbers (e.g. natural rubber or butadiene rubber), thermoplastic resins (e.g. polyamide resin) and thermosetting resins (e.g. epoxy resin) and a mixture of at least two of these members. The carbon black to be surface-coated with silica is desirably one having a nitrogen adsorption specific surface area of 20-250m<2> /g and a DBP absorption of 40-180ml/100g. The amount of component M and silica adhered is 10-50wt.% based on the weight of the carbon black. The composition contains 100 pts.wt. component M and 30-150 pts.wt. component C. Component C may contain a silane coupling agent (e.g. vinyltrichlorosilane).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses a crosslinkable rubber, a thermoplastic resin, or a thermosetting resin as a matrix-forming substance and has silica attached to the surface thereof (hereinafter referred to as silica surface-treated carbon black). ), A high electrical resistance molding particularly suitable for use in the fields of communication cables, optical fiber cable jackets, rubber rollers for copiers, radiator hoses for automobiles, etc. Regarding goods.

[0002]

2. Description of the Related Art In recent years, cables for communication cables and optical fibers have been used.
Cables, rubber rollers for copiers, and lathes for automobiles.
For matrix components in fields such as radiator hoses
High electric resistance car that can give high electric resistance
The development of bon black is desired, for example, Japanese Patent Laid-Open No. 7-
No. 3,164,63 discloses a nitrogen adsorption specific surface area of 15 to 50.
m^Two/ G, DBP oil absorption (D₀) And compressed DBP oil absorption
(D₁) Ratio (D₀/ D ₁) Is in the range of 1.6 to 2.0
Yes, and compressed DBP oil absorption (D₁) Is 45 to 90 ml
/ 100g high resistance carbon brush with characteristics
Is disclosed. However, matrix reinforcement
From the viewpoint of achieving both high resistance and high electrical resistance,
Not enough.

Carbon black having silica adhered to its surface is known as a pigment, for example, Japanese Patent Publication No. 7-302.
In Japanese Patent No. 69, carbon black is dispersed in water,
A method for surface treatment of carbon black for powder coatings is described in which amorphous silica is deposited on the surface of carbon black particles using sodium silicate while adjusting the pH to 6 or higher and keeping the temperature at 70 ° C. or higher. However, this publication does not describe at all about blending the carbon black having the silica adhered to the surface thereof with rubber or other matrix components.

Accordingly, the present invention provides a high electrical resistance molded article obtained by molding a composition containing a matrix reinforcing carbon black capable of imparting high electrical resistance while maintaining the characteristics of reinforcing carbon. With the goal.

[0005]

According to the present invention, at least one matrix-forming substance selected from crosslinkable rubbers, thermoplastic resins and thermosetting resins and silica are used in an amount of 10 to 10% by weight of carbon black. Provided is a high electrical resistance molded article obtained by molding a composition containing 50% by weight of silica surface-treated carbon black adhered to the surface.

[0006]

According to the present invention, as described above, carbon black having silica adhered or deposited on the surface of a matrix material of rubber, thermoplastic resin and / or thermosetting resin (silica surface-treated carbon black) is used. ) Is blended. The amount of silica attached to the silica surface-treated carbon black is generally 10 to 50% by weight, preferably 12 to 45% by weight, based on the carbon black. If the content of this silica is too small, the desired high electric resistance cannot be obtained, and if it is too large, the electric resistance value does not change, which is not preferable.

The method for producing the silica surface-treated carbon black according to the present invention is not particularly limited. For example, first, after producing the carbon black by the oil furnace method or the like,
It is produced by putting in an atmosphere for producing white carbon and adhering silica to the surface of carbon black. As an example, it can be manufactured according to the method described in JP-A-63-63755. That is, carbon black is dispersed in water, the pH is adjusted to 6 or higher, preferably 10 to 11, and the temperature is 70 ° C. or higher, preferably 8 or higher.
It can be produced by, for example, hydrolyzing sodium silicate and adhering or depositing amorphous silica on the surface of carbon black particles while maintaining the temperature at 5 to 95 ° C.

The total amount of silica in the rubber reinforcing agent produced by such a method is not always physically or chemically bound to the surface of carbon black, but observation with a transmission electron microscope (about 60 It has been confirmed that there is silica adhering to the carbon black according to (10,000 times).

The silica surface-treated carbon black according to the present invention preferably has a nitrogen specific surface area (N ₂ SA) of 20 to 20.
It is 300 m ² / g. If the nitrogen specific surface area is less than 20 m ² / g, the reinforcing property to rubber may be insufficient, and the breaking strength and abrasion resistance may be decreased. On the contrary, if it exceeds 300 m ² / g, kneading into rubber becomes difficult. , There is a risk of poor dispersion.

The matrix-forming substances to be incorporated in the molding composition of the molded article according to the present invention are crosslinkable rubber, thermoplastic resin and thermosetting resin, which are used alone or as a mixture of two or more kinds. be able to. Any rubber can be used as the crosslinkable rubber, for example, natural rubber (NR), various butadiene rubbers (BR), various styrene-butadiene copolymer rubbers (SBR), polyisoprene rubbers (IR), butyl rubbers. (IIR), acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene copolymer rubber, ethylene-propylene-diene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber,
It is possible to use isoprene-butadiene copolymer rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorophodrin rubber, polysulfide rubber, silicone rubber, fluororubber, urethane rubber and the like. When a blend is used, the blend ratio is not particularly limited.

The thermoplastic resin as the matrix-forming substance used in the present invention is, for example, a polyamide resin (for example, nylon 6 (N6), nylon 66).
(N66), Nylon 46 (N46), Nylon 11
(N11), nylon 12 (N12), nylon 610
(N610), nylon 612 (N612), nylon 6/66 copolymer (N6 / 66), nylon 6/66 /
610 copolymer (N6 / 66/610), nylon MX
D6 (MXD6), nylon 6T, nylon 6 / 6T copolymer, nylon 66 / PP copolymer, nylon 66 /
PPS copolymer), polyester resin (for example, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polyethylene isophthalate (P
E1), PET / PEI copolymer, polyarylate (P
AR), polybutylene naphthalate (PBN), liquid crystalline polyester, aromatic polyester such as polyoxyalkylene diimidic acid / polybutyrate terephthalate copolymer), polynitrile resin (for example, polyacrylonitrile (PAN), polymethacrylonitrile, Acrylonitrile / styrene copolymer (AS), methacrylonitrile / styrene copolymer, methacrylonitrile / styrene / butadiene copolymer), polymethacrylate resin (eg polymethylmethacrylate (PMMA), polyethylmethacrylate) , Polyvinyl resins (for example, vinyl acetate, polyvinyl alcohol (PVA), vinyl alcohol / ethylene copolymer (EVOH), polyvinylidene chloride (PDVC), polyvinyl chloride (PVC), vinyl chloride / vinyl chloride) Copolymer, vinylidene chloride / methyl acrylate copolymer), cellulose resin (eg cellulose acetate, cellulose acetate butyrate), fluorine resin (eg polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), polychlorofluoroethylene) (P
CTFE), tetrafluoroethylene / ethylene copolymer), imide resin (eg aromatic polyimide (P
I)) etc. can be mentioned.

The thermosetting resin used as the matrix-forming substance in the present invention is, for example, an epoxy resin (glycidyl ether type, glycidyl ester type, glycidyl amine type, alicyclic type), unsaturated polyester resin, phenol resin. , Urea / melamine resin, polyurethane resin, silicone resin, etc.

According to the present invention, it is preferable to add 30 to 150 parts by weight, preferably 35 to 120 parts by weight of silica surface-treated carbon black to 100 parts by weight of the matrix-forming substance. If the blending amount is too small, the desired curing cannot be obtained, and conversely, if the blending amount is too large, the hardness may become too high and the workability may be deteriorated.

In the rubber composition according to the present invention, in addition to the above-mentioned silica surface-treated carbon black, any carbon black and / or silica usually blended in a rubber composition can be used in combination. In this case, the amount of the usual carbon black and / or silica should not exceed 10 times, preferably 8 times the weight of the silica surface-treated carbon black. If the amount of this carbon black is too large,
It is not preferable because a desired effect cannot be obtained.

In the present invention, the carbon black to which silica is attached on the surface thereof preferably has a nitrogen adsorption specific surface area (measured according to ASTM D 3037) of 20 to 25.
0 m ² / g, more preferably at 25~150m ² / g,
DBP oil absorption (measured according to JIS K 6221)
Is 40 to 180 ml / 100 g. If the value of the nitrogen adsorption specific surface area of carbon black is too low, the reinforcing effect on the matrix is reduced, which is not preferable, while if it is too high, dispersion during kneading becomes difficult, which is not preferable.

There are no particular restrictions on the properties of the carbon black without silica attached, which can be optionally compounded in the molding composition of the high electrical resistance molded product according to the present invention, but preferably normal rubber. It is used for blending and is a carbon of SRF to SAF grade as a particle size grade. In some cases, carbon black for color may be used. These may be blended.

According to a preferred embodiment of the present invention, a silane coupling agent can be further added to the above-mentioned rubber composition with respect to silica surface-treated carbon black. If the blending amount of the silane coupling agent is too large, not only the physical properties are not particularly improved, but also the cost is increased and the scorch time is shortened, which is not preferable.

As the silane coupling agent which can be used in the preferred embodiment of the present invention, any silane coupling agent which has been conventionally compounded in a rubber composition together with a silica filler can be compounded. Examples of such a silane coupling agent include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ -Glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- Methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxy Orchid, N-beta (aminoethyl)
γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxy Examples thereof include silane and bis- (3- [triethoxysilyl] -propyl) -tetrasulfan.

In the molding composition according to the present invention, in addition to the matrix-forming substance, carbon black having silica attached to the surface thereof, and an optional silane coupling agent, any of those commonly used in the art is used. The compounding agents, such as sulfur, organic peroxides, softening agents, antioxidants, vulcanization accelerators, fillers, plasticizers, etc., can be appropriately compounded, if necessary, within the usual compounding amount range.

[0020]

EXAMPLES The present invention will be further described with reference to the following examples, but it goes without saying that the scope of the present invention is not limited to these examples.

Preparation of silica surface-treated carbon black The silica surface-treated carbon black was prepared by the following method. That is, after preparing a carbon black slurry according to a conventional method and heating it to 90 ° C., the diluted JIS No. 3 sodium silicate was added over 4 hours with a metering pump to adjust the pH.
Silica was deposited on the carbon surface while maintaining 5 to 10 with dilute sulfuric acid and aqueous sodium hydroxide. Then, the mixture was left at pH 6 for 6 hours, filtered, washed with water and dried to obtain the desired product. The silica content was varied by adjusting the amount of sodium silicate added.

Silica surface-treated carbon black (CB)
The silica content in the inside was determined by ashing the silica surface-treated carbon black in an electric furnace at 600 ° C. and then performing the following treatment together with hydrogen fluoride by the following equation. Silica content (%) = [(hydrogen fluoride treatment weight loss) / (weight of surface treated CB)] × 100

The properties of the silica-treated carbon black prepared are shown in Table I below. The measuring method is as follows. Nitrogen specific surface area (N ₂ SA): ASTM D3037 Iodine adsorption amount (IA): JIS K6221 “Carbon black test method for rubber” Hydrogen fluoride treatment: Weigh about 200 mg of a sample and put it into a beaker made of polyethylene and put it in distilled water. After moistening with, add 5 mg of hydrogen fluoride. Stir this, leave it for 5 minutes,
Filter by suction, wash well with distilled water and dry.

Examples 1 to 4 and Comparative Examples 1 to 4 Various rubber compositions were mixed and kneaded by a Banbury mixer and a kneading roll machine according to a conventional method according to the compounding contents (parts by weight) shown in Table II and Table III. Prepared. These rubber compositions were press-vulcanized at 160 ° C. for 20 minutes to prepare target test pieces, and various tests were conducted. The results are shown in Table III. The standard formulation is as follows.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

Example 5 and Comparative Example 5 Using the formulations of Example 1 and Comparative Example 3, rubber hoses shown in the table below were prepared.

[0029]

[Table 4]

As shown in Table IV, the rubber hose using the surface-treated carbon black of the present invention is excellent in electric insulation. Therefore, when it is used as a pipe for gas (LPG or city gas, for example), a stray current in a house is generated. There is little risk of spark accidents.

[0031]

In general, in order to impart a high electric resistance to the matrix, the particle size is large contrary to the imparting of conductivity,
Although soft carbon, which has a low structure and suppresses the development of internal crystallites, is used, it has a problem of poor reinforcement. Further, Japanese Patent Application Laid-Open No. 7-316463 proposes that carbon having a specific colloidal characteristic improves the reinforcing property and the electrical conductivity, but further improvement in the reinforcing property and high electric resistance is required. On the other hand, in the carbon black of the present invention, the reinforcing property and electric resistance can be controlled by selecting what kind of carbon black is selected and by setting the silica adhesion amount.
As a result, it is possible to impart high reinforcement and high electrical resistance.

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Claims (3)

[Claims] 1. A crosslinkable rubber, at least one matrix-forming substance selected from a thermoplastic resin and a thermosetting resin, and silica in an amount of 1% by weight of carbon black.
A high electrical resistance molded article obtained by molding a composition containing 0 to 50% by weight of silica surface-treated carbon black adhered to the surface. 2. The amount of silica surface-treated carbon black compounded is 30 to 1 per 100 parts by weight of the matrix-forming substance.
The molded product according to claim 1, which is 50 parts by weight. 3. The molded article according to claim 1 or 2, which is formed by incorporating or adsorbing a silane coupling agent into silica surface-treated carbon black.