JP2003263923A - Black conductive synthetic resin composition containing fine powder of rbc or crbc and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a black conductive synthetic resin composition in which various additives can be uniformly dispersed. <P>SOLUTION: The black conductive synthetic resin is prepared by dispersing an impalpable powder of carbon material (namely, RBC or CRBC), made from defatted rice bran and a thermosetting resin by mixing, kneading, drying and burning in an inert gas atmosphere, with a synthetic resin of a mass ratio of 20-90:80-10. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a conductive black synthetic resin composition in which a fine powder of RBC or CRBC is uniformly dispersed in a resin. Kazuo Horikirikawa, the first inventor of the present case, is trying to obtain a porous carbon material by using rice bran, which is discharged 900,000 tons / year in Japan and 33 million tons / year worldwide. Known for research. (Functional Materials May 1997 Vol.17 N
o. 5 p24-28) Here, a degreased bran obtained from rice bran and a thermosetting resin are mixed and kneaded, and a pressure-molded molded body is dried, and then the dried molded body is subjected to an inert gas atmosphere. RB ceramics (hereinafter referred to as RBCs), which is a carbon material fired therein, and a manufacturing method thereof are shown. The thermosetting resin may be any one as long as it is thermoset, and typically, a phenol resin, a diaryl phthalate resin, an unsaturated polyester resin, an epoxy resin, a polyimide resin, a triazine resin is used. Can be mentioned. Particularly, a phenol resin is preferably used.
The mixing ratio of the degreased bran and the thermosetting resin is 5 by mass.
0 to 90:50 to 10, but preferably 75:25
Is used. The firing temperature is 700 ° C. to 1000 ° C., a rotary kiln is usually used, and the firing time is about 40 to 120 minutes. CRB ceramics (hereinafter CR
(BC) is an improved material of RB ceramics obtained from a degreased bran obtained from rice bran and a thermosetting resin. The degreased bran obtained from rice bran and the thermosetting resin are mixed and kneaded, After primary firing in an inert gas at 700 ° C to 1000 ° C, it is pulverized to about 100 mesh or less to give a carbonized powder, the carbonized powder and a thermosetting resin are mixed and kneaded, and a pressure of 20 MPa to 30 MPa is applied. After molding, the molded body is again 500 ° C to 1100 ° C in an inert gas atmosphere.
It is a black resin or porous ceramics obtained by heat treatment in.

RBC and CRBC have the following excellent features.・ High hardness.・ The shape of the particles is distorted. -The coefficient of expansion is very small. -The organizational structure is porous.・ Has electrical conductivity.・ Small and light weight.・ The coefficient of friction is very small.・ Excellent wear resistance. -Since the material is rice bran, it has little adverse effect on the global environment, leading to resource conservation. In the present invention, such RBC and CRBC have an average particle diameter of 300 μm or less, preferably 10 to 100 μm.
Particularly preferably, the present invention relates to a black synthetic resin composition for electroconductivity, which is obtained by pulverizing it to 10 to 50 μm and mixing it with a synthetic resin.

[0003]

2. Description of the Related Art Conventionally, conductive black synthetic resin compositions have been
A fine powder of Bon Black was blended. If necessary, the conductive black synthetic resin composition containing carbon black fine powder may contain stabilizers, antioxidants, colorants, antistatic agents, ultraviolet absorbers, lubricants, flame retardants, and other constitutions. Various fillers such as fillers are added, but stabilizers, antioxidants, colorants, antistatic agents, UV absorbers, lubricants, flame retardants, other constitutional fillers, etc. have differences in polarity, solubility, specific gravity, etc. Therefore, it is very difficult to uniformly disperse the resin in the resin, and it is difficult to obtain a conductive black synthetic resin composition having stable conductive characteristics.

[0004]

The present inventor has found that when various additives are dispersed in various synthetic resins, if the additives that cannot be well dispersed in the resin are RB ceramics and / or CR.
The fact that the presence of fine powder of B ceramics exhibits high dispersibility in which stabilizers, antioxidants, colorants, antistatic agents, UV absorbers, lubricants, flame retardants, and other body fillers are more evenly dispersed. Was discovered, and the present invention was completed. The bulk specific gravity of RB ceramics and / or CRB ceramics is about 1.22 to 1.35 (g · cm ⁻³ ).
(For bulk specific gravity, the JIS R 1601.4 test piece
IS R 7222.7 The bulk specific gravity was measured by the measuring method. Since RB ceramics and / or CRB ceramics are porous, only bulk specific gravity can be measured. ) And RB made into a fine powder
It was found that by using ceramics and / or CRB ceramics dispersed in a resin, a black conductive synthetic resin composition having stable characteristics can be obtained.

[0005]

The present inventor has found that RBC (R
B ceramics) or CRBC (CRB ceramics)
Surprisingly as a result of intensive research focusing on the specificity of RBC or CRBC, fine powders of RBC or CRBC were found to be stabilizers, antioxidants, colorants, antistatic agents, UV absorbers, lubricants, flame retardants, and other constitutions. It has been found that even if the filler or the like is hydrophilic or lipophilic, it has the property (high dispersibility) that it can be uniformly dispersed in the synthetic resin. We have not fully clarified why such a phenomenon occurs, but probably RBC
It is assumed that (RB ceramics) or CRBC (CRB ceramics) is a porous carbon body having an inorganic substance such as phosphorus (P) and potassium (K). At the same time, RBC (RB ceramics) or CR
It was also found that when a fine powder of BC (CRB ceramics) is contained in a synthetic resin and molded, a resin molded product having a surface with low friction characteristics can be obtained. A typical production method of the black synthetic resin composition for electrical conduction of the present invention is RBC or CRB.
After premixing the fine powder of C with at least one additive selected from the group consisting of a stabilizer, an antioxidant, a colorant, an antistatic agent, an ultraviolet absorber, a lubricant, a flame retardant and other fillers. It is easily obtained by adding the mixture at a temperature near the melting point of the synthetic resin and kneading to uniformly disperse the fine powder of RBC or CRBC and the additive.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The fine powder of RBC or CRBC used in the present invention has an average particle diameter of 300 μm or less. Particularly, those having an average particle diameter of 10 to 100 μm, more preferably 10 to 50 μm are suitable as the black synthetic resin composition for electroconductivity.

The synthetic resin which can be used in the present invention includes thermoplastic resins such as polyamide, polyester and polyolefin. Specifically, nylon 66 (polyhexamethylene adipamide), nylon 6 (polycapramide), nylon 11 (polyundecane amide), nylon 12, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polypropylene, polyethylene, polyphenylene sulfide, etc. A thermoplastic resin may be used. Especially nylon 6
6 is preferably used. These thermoplastic resins may be used alone or in combination of two or more.

Further, a thermosetting resin may be used in combination without departing from the scope of the present invention. Examples of such thermosetting resins include phenolic resins, diarylphthalate resins, unsaturated polyester resins, epoxy resins, polyimide resins, triazine resins and the like. As long as there is no problem in the compatibility of the resins with each other, one or two or more of them can be added in an amount of about 20% by mass or less of the total resin composition. In the present invention, the addition ratio varies depending on the intended electrical conductivity, but generally, the addition ratio of the synthetic resin is 20 to 90: mass ratio of fine powder of RBC or CRBC: synthetic resin.
It is preferably 80 to 10. If the addition ratio of the synthetic resin exceeds 80% by mass, the electrical conductivity characteristics deteriorate, and 1
If it is 0% by mass or less, molding becomes difficult.

As the stabilizer used in the present invention, a heat stabilizer represented by a phosphoric acid ester or a phosphorous acid ester or a light stabilizer includes a hindered amine light stabilizer, a phenylbenzoate light stabilizer, There are nickel complex salts. As a specific example of the hindered amine-based or phenylbenzoate-based light stabilizer, bis (2,2
2,6,6-tetramethyl-4-piperidyl) sepacate, succinic acid and N- (2-hydroxypropyl) -2,
Condensate with 2,6,6-tetramethyl-4-hydroxypiperidine, tetrakis (2,2,6,6-tetramethyl-4-piperidyl), 1,2,3,4-butanetetracarboxylate, N , N'-bis (2,2,6,6-
Polycondensation product of tetramethyl-4-piperidyl) hexamethylenediamine and 1,2-dibromoethane, bis (2,2
2,6,6-tetramethylpiperidyl) adipate, bis (2,2,6,6-tetramethylpiperidyl) fumarate, poly [[6- (1,1,3,3-tetramethylbutyl) imino-1, 3,5-Triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) Imino]], 2,4-di-
t-Butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, 4-octylphenyl-3,5
-Di-t-butyl-4-hydroxybenzoate, n-
Hexadecyl-3,5-di-t-butyl-4-hydroxybenzoate and the like can be mentioned.

Examples of the antioxidant used in the present invention include phenol-based, phosphorus-based and sulfur-based antioxidants.
Here, as the phenolic antioxidant, 2,6-di-t
-Butyl-4-methylphenol, tris (3,5-di-t-
Butyl-4-hydroxybenzyl) isocyanurate, tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane, n-octadecyl-3- (3 ', 5'-di -t-butyl-4'-hydroxyphenyl) propionate, 4,4'butylidene bis- (3-methyl-6-t-butylphenol, triethylene glycol-bis [3- (3-t-butyl-4-hydroxy) -5-methylphenyl) propionate], 3,9-bis [2- [3 (3-t-butyl-4-humanroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl] -2,4 8,10-Tetraoxaspiro [5,5]
For example, undecane.

Further, as phosphorus antioxidants, trisnonylphenyl phosphite, distearyl pentaerythritol diphosphite, tris (2,4-di-t-
Butylphenyl) phosphite, tetrakis (2,4-
Di-t-butylphenyl) -4,4'-biphenylene-
Di-phosphonite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol-diphosphite, 2,2,- Examples thereof include methylenebis (4,6-di-t-butylphenyl) octyl phosphite. Examples of the sulfur-based antioxidant include dilauryl-3,3'-thiodipropionate, dimyristyl-3,3'-thiodipropionate, distearyl-3,3'-thiodipropionate,
Pentaerythritol tesrakis (3-lauryl thiopropionate) etc. can be mentioned.

The color of the conductive black synthetic resin composition of the present invention is naturally black, and a colorant is used to add depth to this black color. Colorants include dyes and pigments, and addition of pigments is particularly preferable. Specific examples of the pigment include white pigments such as titanium oxide, zinc white, lead white, and lithobon, black pigments such as aniline black, iron black, carbon black, yellow lead, yellow iron oxide, titanium yellow, Hansa yellow, and benzine. Yellow pigments such as yellow and permanent yellow, chrome vermillion, permanent orange,
Orange pigments such as vulcan first orange, iron oxides, brown pigments such as permanent brown and para brown, red iron oxide, cadmium red, antimony vermillion, permanent red, alizarin lake, thioindigo red, PV
Red pigments such as carmine and monolight fast red,
Purple pigments such as cobalt purple, manganese purple, fast violet, methyl violet lake, ultramarine blue, dark blue, cobalt blue, peacock blue lake, Victoria blue lake, metal-free phthalocyanine blue, blue pigments such as indigo, chrome green, chromium oxide, emerald In addition to green pigments such as green, green gold, acid green lake, malachite green lake and phthalocyanine green, metal powder pigments and the like can be mentioned.

The ultraviolet absorbers and ultraviolet absorbers used in the present invention include benzotriazole compounds, benzophenone compounds, salicylate compounds, cyanoacrylate compounds, benzoate compounds, oxazalide compounds, hindered amine compounds and nickel complex salts. Etc. Further, as the lubricant used in the present invention, talc, magnesium carbonate, calcium carbonate,
Kaolin is also included. Examples of the flame retardant used in the present invention include tetrabromobisphenol A derivatives,
Halogen-containing compounds such as hexabromodiphenyl ether and tetrabromophthalic anhydride: Triphenyl phosphate, triphenyl phosphite, phosphorus-containing compounds such as red phosphorus and ammonium polyphosphate: Nitrogen-containing compounds such as urea and guanidine: Silicon oil, organic Silicon-containing compounds such as silane and aluminum silicate:
Examples thereof include antimony compounds such as antimony trioxide and antimony phosphate. Further, examples of the other fillers used in the present invention include glass flakes, glass beads, silica, quartz, amorphous silicic acid, alumina, metal powder, calcium silicate, mica, wollastonite, and the like. Further, in the present invention, CRB, conductive materials other than CRBC, such as carbon black, graphite, carbon fiber,
It goes without saying that a good conductive filler having a small electric resistivity, such as metal fiber or metal powder, can be used in combination. Molding of the black synthetic resin composition for electroconductivity of the present invention can be carried out by various procedures which are usually carried out. For example, it can be made into pellets and molded by a processing machine such as an extruder, an injection molding machine, or a roll mill. It has also been found that it is better to set the mold temperature to a slightly lower temperature. Basically, the temperature in the range of the glass transition point or melting point of the synthetic resin is good. Further, it has been found that a mold having a good friction characteristic can be obtained when the mold is gradually cooled rather than rapidly cooled.

The embodiments of the present invention are summarized as follows. (1) A black synthetic resin composition for electric conduction, which is obtained by dispersing 20 to 90:80 to 10 in a mass ratio of fine powder of RBC or CRBC: synthetic resin in the synthetic resin. (2) The synthetic resin is one or more resins selected from nylon 66, nylon 6, nylon 11, nylon 12, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polypropylene, polyethylene and polyphenylene sulfide. The conductive black synthetic resin composition described. (3) The average diameter of fine powder of RBC or CRBC is 30
The black synthetic resin composition for electroconductivity as described in 1 or 2 above, which is 0 μm or less. (4) The average diameter of fine powder of RBC or CRBC is 10
The black synthetic resin composition for electric conduction as described in 3 above, which has a thickness of ˜50 μm. (5) Any one of the above 1 to 4 containing at least one additive selected from a stabilizer, an antioxidant, a colorant, an antistatic agent, an ultraviolet absorber, a lubricant, a flame retardant and other fillers. The black synthetic resin composition for electroconductivity described in 1. (6) One or more thermosetting resins of the group consisting of a phenolic resin, a diaryl phthalate resin, an unsaturated polyester resin, an epoxy resin, a polyimide resin, and a triazine resin are added to the entire composition. The black synthetic resin composition for electrical conduction according to any one of 1 to 5 above, which is contained in an amount of 20% by mass or less. (7) Carbon black, graphite, carbon fiber, metal fiber,
The black synthetic resin composition for electroconductivity according to any one of 1 to 6 above, which uses one kind or two or more kinds of good conductive fillers selected from metal powders in combination. (8) RBC or CRBC fine powder and at least one additive selected from the group consisting of stabilizers, antioxidants, colorants, antistatic agents, ultraviolet absorbers, lubricants, flame retardants, and other fillers. Is mixed in advance, the mixture is added to the synthetic resin at a temperature near the melting point of the synthetic resin, and the mixture is kneaded.

(Examples) The present invention will be described in more detail based on examples. Example 1 (Production of RBC fine powder) Degreased bran 7 obtained from rice bran
50g and liquid phenol resin (resole) 250g
Were mixed and kneaded while being heated to 50 ° C to 60 ° C. A homogeneous mixture with plasticity was obtained. The mixture was baked at 900 ° C. for 100 minutes in a nitrogen atmosphere using a rotary kiln, and the obtained carbonized product was further crushed using a crusher and then sieved with a 150 mesh screen to have an average particle size of 140 to 160 μm. An RBC fine powder was obtained. (Preparation of RBC fine powder and synthetic resin mixture) RB obtained
C fine powder 500g, nylon 66 powder 500g 240
The mixture was mixed and kneaded while being heated to 290 to 290 ° C. A homogeneous mixture with plasticity was obtained. The content of the RBC fine powder was 50% by mass. (Preparation of test piece) A black synthetic resin composition for electroconductivity obtained by melting and mixing RBC fine powder and nylon 66 was injection molded to prepare a test piece.

Example 2 Using the same method as in Example 1, the average particle size was 140-16.
An RBC fine powder having a size of 0 μm was obtained. (Preparation of RBC fine powder and synthetic resin mixture) RB obtained
C fine powder 700g, nylon 66 powder 300g 240
The mixture was mixed and kneaded while being heated to 290 to 290 ° C. A homogeneous mixture with plasticity was obtained. The content of RBC fine powder was 70% by mass. (Preparation of test piece) A black synthetic resin composition for electroconductivity obtained by melting and mixing RBC fine powder and nylon 66 was injection molded to prepare a test piece.

Example 3 (Production of RBC fine powder) Defatted bran 7 obtained from rice bran
50g and liquid phenol resin (resole) 250g
Were mixed and kneaded while being heated to 50 ° C to 60 ° C. A homogeneous mixture with plasticity was obtained. The mixture is heated to 1000 ° C in a nitrogen atmosphere using a rotary kiln.
The obtained carbonized product was further pulverized by using a pulverizer and then passed through a 400-mesh sieve to obtain RBC fine powder having an average particle size of 40 to 50 μm. (Preparation of RBC fine powder and synthetic resin mixture) RB obtained
C fine powder 700g, nylon 66 powder 300g 240
The mixture was mixed and kneaded while being heated to 290 to 290 ° C. A homogeneous mixture with plasticity was obtained. The content of RBC fine powder was 70% by mass. (Preparation of test piece) A black synthetic resin composition for electroconductivity obtained by melting and mixing RBC fine powder and nylon 66 was injection molded to prepare a test piece.

Example 4 (Production of CRBC fine powder) 750 g of defatted bran obtained from rice bran and 250 g of liquid phenol resin (resole) were mixed and kneaded while heating at 50 ° C to 60 ° C. A homogeneous mixture with plasticity was obtained. The mixture was baked at 900 ° C. for 60 minutes in a nitrogen atmosphere using a rotary kiln. The carbonized product thus obtained is pulverized by using a pulverizer and then 200
After sieving through a mesh, the average particle size is 100-120 μm
A fine RBC powder was obtained. The obtained RBC fine powder 75
0 g and solid phenol resin (resole) 500 g were mixed and kneaded while heating at 100 ° C to 150 ° C. A homogeneous mixture with plasticity was obtained. Then
The plastic was pressure-molded at a pressure of 22 MPa into a spherical shape having a diameter of about 1 cm. The mold temperature was 150 ° C. Remove the molded body from the mold, raise the temperature at a rate of 1 ° C / min up to 500 ° C in a nitrogen atmosphere, and hold at 500 ° C for 60 minutes,
Sintered at 900 ° C. for about 120 minutes. Next, the temperature was lowered at a cooling rate of 2 to 3 ° C./min up to 500 ° C., and when the temperature reached 500 ° C. or less, the mixture was naturally cooled. The obtained CRBC molded product was crushed by using a crusher and then passed through a 500-mesh sieve to obtain CRBC fine powder having an average particle size of 20 to 30 μm. (Preparation of CRBC Fine Powder and Synthetic Resin Mixture) Obtained C
RBC fine powder 500g, nylon 66 powder 500g 2
The mixture was mixed and kneaded while being heated to 40 ° C to 290 ° C.
A homogeneous mixture with plasticity was obtained. The content of CRBC fine powder was 50% by mass. (Preparation of test piece) A black synthetic resin composition for electroconductivity obtained by melt-mixing CRBC fine powder and nylon 66 was injection-molded to prepare a test piece.

Examples 5-9 and Comparative Example 1 Same as Examples 1-4, RBC or CRBC fine powder, 2,6-di-t-butyl-4-methylphenol as antioxidant, malachite green lake as pigment A test piece was prepared under the conditions shown in Table 1 by adding a tetrabromobisphenol A derivative as a flame retardant. Further, a comparative test 1 was carried out by using a commercially available activated carbon fine powder (average particle diameter 30 μm) in place of the RBC or CRBC fine powder, and a comparative test 2 in which no RBC or CRBC fine powder or a commercially available activated carbon fine powder was added.

[0020]

[Table 1] Table 2 summarizes the characteristics of the conductive black synthetic resin compositions obtained in Examples 1 to 9. The dispersibility was evaluated by visual inspection.

[0021]

[Table 2]

[0022]

As is clear from the results of Table 2, the conductive black synthetic resin composition comprising the fine powder of RBC or CRBC of the present invention and the synthetic resin is excellent in the dispersibility of the additive, Further, it was found that increasing the content of fine powder of RBC or CRBC is useful as a conductive resin composition.

Continued front page    F-term (reference) 4F070 AA13 AA15 AA42 AA47 AA54                       AA58 AC04 AC37 AD04 AE01                       AE03 AE04 AE05 AE06 AE07                       AE09 FB08                 4J002 BB031 BB121 CB001 CF061                       CF071 CL011 CL031 CN011                       DA016 DA027 DA057 DE107                       DE127 DE137 DE147 DE237                       DH057 DJ017 DJ037 DJ047                       DJ057 DL007 EJ027 EJ067                       EL138 ER027 ET017 EU087                       EU187 EU197 EV067 EW047                       EW067 EW117 EX007 FA027                       FA047 FD037 FD047 FD057                       FD097 FD107 FD137 FD177                 5G301 DA18 DA42 DA43 DA51 DA53                       DD10 DE01

Claims (6)

[Claims] 1. A conductive black synthetic resin composition comprising 20 to 90:80 to 10 in a mass ratio of fine powder of RBC or CRBC: synthetic resin dispersed in the synthetic resin. 2. The synthetic resin is one or more resins selected from nylon 66, nylon 6, nylon 11, nylon 12, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polypropylene, polyethylene and polyphenylene sulfide. Item 1. A black synthetic resin composition for electrical conduction according to item 1. 3. The conductive black synthetic resin composition according to claim 1, wherein the RBC or the fine powder of CRBC has an average diameter of 300 μm or less. 4. The conductive black synthetic resin composition according to claim 3, wherein the RBC or the fine powder of CRBC has an average diameter of 10 to 50 μm. 5. A stabilizer, an antioxidant, a colorant, an antistatic agent, an ultraviolet absorber, a lubricant, a flame retardant, and at least one additive selected from other fillers.
A black synthetic resin composition for electrical conduction according to claim 4. 6. A fine powder of RBC or CRBC, a stabilizer, an antioxidant, a colorant, an antistatic agent, an ultraviolet absorber,
After premixing at least one additive selected from the group consisting of lubricants, flame retardants, and other extender fillers, the mixture is added to the synthetic resin at a temperature near the melting point of the synthetic resin,
A method for producing a conductive black synthetic resin composition to be kneaded.