CN1061579C - Process for preparing copper powder for electromagnetic shield conducting paint - Google Patents
Process for preparing copper powder for electromagnetic shield conducting paint Download PDFInfo
- Publication number
- CN1061579C CN1061579C CN 95111554 CN95111554A CN1061579C CN 1061579 C CN1061579 C CN 1061579C CN 95111554 CN95111554 CN 95111554 CN 95111554 A CN95111554 A CN 95111554A CN 1061579 C CN1061579 C CN 1061579C
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- China
- Prior art keywords
- copper powder
- silver
- preparation
- edta
- acid ester
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Abstract
The present invention relates to a method for preparing silver-plated copper powder for electromagnetic shield conducting paint. Disodium edta salt is used as a chelating disperse agent for implementing copper-silver displacement reaction. Micro silver ions are reduced by tartaric acid so that silver is deposited on the surface of the copper powder and is filtered and dried to prepare the silver-plated copper powder which is then treated by mixed solution composed of titanate and fatty acid ester. Thus, the electricity conducting copper powder with a multi-layer structure is prepared. The resistance value of the copper powder is 0.3 omega (the internal resistance of a universal meter is 0.3 omega). The copper powder has the characteristics of low silver content, even plating performance, good effect of the shield of electromagnetic wave interference, etc. The present invention is widely used for preparing the conducting paint, a conducting adhesive and conducting plastics.
Description
The present invention relates to a kind of preparation method of copper powder for electromagnetic shield conducting paint, or rather, the present invention relates to a kind of preparation method of silver-plated copper powder of sandwich construction.
Along with digital device carries the universal of machine (for example private with electronic computer, dry copier, facsimile machine and do not have code telephone set etc.), require the seal box of these machines must shield electromagnetic interference, common way is that the coating conductive coating paint shields electromagnetic interference on seal box.For now, it is four kinds that the kind of the conductive coating paint that the shielding electromagnetic wave is used has nickel system, copper system, silver-plated copper system and silver, takes all factors into consideration the effect and the price factor of shielding Electromagnetic Interference, and silver-plated copper is that the application of coating is increasing.
Copper is that the effect of coating shielding Electromagnetic Interference is excellent, but the resistance to oxidation poor stability, the time has been grown, and copper powder forms oxide layer, makes it become insulator from electric conductor, thereby loses shielding Electromagnetic Interference effect.In order to overcome this shortcoming; in prior art CN 1049622A; a kind of preparation method of silver-plated copper powder of sandwich construction is disclosed; it utilizes the characteristics of silver-colored resistance to oxidation and good stability; the conductive shield electromagnetic wave effect that keeps copper; after the copper powder degreasing; remove the oxide-film on copper powder surface with acid; after being washed till neutrality; with conventional method silver powder is plated on the copper powder surface, forms layer protective layer, after filtering, being washed to neutrality; handle copper powder with titanate coupling agent, drying makes the conductive copper powder of sandwich construction.The specific insulation of sticking with paste with the conduction of this copper powder production is 4.0 * 10
-4Ω cm.In the method, coat one deck silver intermediate protective layer on the copper powder surface with general chemical method, the general chemical method is not here commented, and in general, silver-colored intermediate protective layer is uneven to the covering of copper powder.In the sandwich construction copper powder that this method makes, the content of silver is higher, is generally 1～30% (weight), and the best is 5～20% (weight), so the production cost of this copper powder is higher.
The objective of the invention is to overcome weak point of the prior art, prepare that a kind of silver content is low, plating evenly, the good silver-plated copper powder of shielding Electromagnetic Interference effect.The silver-plated amount of this copper powder is 1～5% of a copper powder weight, and silver-colored rate 〉=more than 95% is covered on the copper powder surface, with specific insulation≤5.0 * 10 of the electrically-conducting paint of this copper powder production
-4Ω cm.Another object of the present invention is to make the filler of electrically-conducting paint, electroconductive binder and conductive plastics with the silver-plated copper powder that the present invention makes.
The present invention is a kind of preparation method of copper powder for electromagnetic shield conducting paint; be characterized in: in EDTA (EDTA) and sodium-salt aqueous solution thereof; add the thin copper powder of electrolysis (average grain diameter is 25 μ m); under 20～65 ℃; stir; then add silver nitrate aqueous solution, make copper displacement silver ion, allow deposition of silver on the surface of copper powder; then; add reductive acid, micro silver ion in the reducing solution makes trace silver also be deposited on the copper powder; form the silver-colored protective layer of one deck densification on the copper powder surface; above-mentioned reactant liquor after filtration; after the drying, the silver-plated copper powder that obtains is handled with the organic acid ester mixed liquor, makes anti-oxidant; the conductive copper powder of sandwich construction.
EDTA of the present invention (EDTA) and sodium salt thereof are meant that selection is a kind of, wherein preferable with disodium salt arbitrarily from EDTA and single sodium salt, disodium salt and trisodium salt, and its consumption is 1～6% of a copper powder weight, and the best is 2～4%.EDTA here and sodium salt thereof can with copper ion in conjunction with forming chelate complex, it has played chelating and has disperseed, in addition because its shows faintly acid, so can remove the surface oxide layer of copper powder again.
It is 1.5～8% of copper powder weight that the present invention adds the silver nitrate consumption, and the silver-colored compacted zone silver content on copper powder surface is 1～5% of a copper powder weight.After silver nitrate adds, the displacement reaction of copper, silver having taken place, makes deposition of silver at last on copper powder.
Reductive acid among the present invention is that selection is a kind of, wherein preferable with tartaric acid arbitrarily from tartaric acid, oxalic acid, and its consumption is 1～5% of a copper powder weight, and the silver ion of trace also is plated on the copper powder surface trace silver in the reducible solution of tartaric acid.
Organic acid ester mixed solution among the present invention is meant the mixture of titanate esters and fatty acid ester, and the mixed proportion of titanate esters and fatty acid ester is between 20: 80～80: 20, and their total additions are 2～8% of copper powder weight, and the best is 2～5%.
Titanate esters among the present invention is to have to select a kind ofly in the ester class of following general formula, and general formula is:
(RO)x-Ti-(OR’)
4-x，
Wherein: RO is that R is C
2～C
4The hydrophilic radical of carbochain,
OR ' is that R ' is C
3～C
13The lipophile group of carbochain,
X is the integer between 1～3.
They can be isopropyl three (dioctyl phosphinylidyne) titanate esters, isopropyl three (dioctyl pyrophosphoryl) titanate esters, two (dioctyl phosphinylidyne) ethylidene titanate esters etc.
Fatty acid ester is C
8～C
18High-grade aliphatic ester, wherein the best is tristerin and isopropyl stearate.
Copper powder with method for preparing is measured with universal meter, and resistance value is 0.3 Ω (the universal meter internal resistance value is 0.3 Ω), with electrically-conducting paint specific insulation≤5 * 10 of this copper powder preparation
-4Ω cm.
The present invention has a significant effect compared with the prior art, and the silver coating plating of the silver-plated copper powder that the present invention makes is even, silver content is low, and its silver-plated amount only is 1～5% of a copper powder weight, the silver-colored rate 〉=more than 95% covered on copper powder surface.The resistance value of the silver-plated copper powder that makes with the present invention is 0.3 Ω (the universal meter internal resistance value is 0.3 Ω), and stores more than 6 months, and resistance value still is 0.3 Ω.Specific insulation≤5 * 10 with the electrically-conducting paint of this copper powder preparation
-4Ω cm.Under 500 megahertzes, electromagnetic shielding is 57～60dB.40 ℃ of relative humidity be 95% and aging 100 hours situations under, electromagnetic shielding is 57～58dB, effectiveness is good.The following examples are to the specifying of content of the present invention, but are not limitation of the present invention.
Embodiment 1
2.5 gram EDTA disodium salts and 300ml distilled water are joined in 2 liters of reactors that have agitating device, be heated to 50 ℃, be stirred well to the EDTA sodium salt and dissolve fully, add 100 gram 600 orders (25 μ m) copper powders, stirred 5～10 minutes, to being uniformly dispersed.Then 4.7 gram silver nitrates and 150ml water mixed solutions are added dropwise in the reaction vessel, are controlled at and added in the kind in 30～45 minutes.This moment, temperature was 45～50 ℃, reacted 45～60 fens kinds after dropwising again, then 2 gram tartaric acid and 100ml water mixed solution was added dropwise in the reaction vessel, and kind dripped in about 20 minutes, continued 30 fens kinds of reaction.With distilled water reaction solution is washed till neutrality, through suction filtration, the silver-plated copper powder that obtains is dried with infra-red furnace, handle by isopropyl three (dioctyl phosphinylidyne) titanate esters of weight ratio mixing in 20: 80 and the mixed liquor of tristerin with 3 grams then, after the drying, get the conduction silver-plated copper powder of the uniform sandwich construction of 90 gram plating.This copper powder is measured with universal meter, and resistance value is 0.3 Ω (the universal meter internal resistance is 0.3 Ω), and room temperature storage is after 6 months, and resistance value is still for being 0.3 Ω.
Embodiment 2
Except that the EDTA disodium salt is that 2 grams, silver nitrate are that 3.14 grams, tartaric acid are that the mixed liquor of 2 grams, isopropyl three (dioctyl phosphinylidyne) titanate esters and tristerin is 2 grams, all the other prescriptions, reaction condition and step are with embodiment 1, and the result gets the conduction silver-plated copper powder of the uniform sandwich construction of 89.2 gram plating.The resistance value of this copper powder is with embodiment 1.
Embodiment 3
Except that the EDTA disodium salt is that 4 grams, silver nitrate are that 6.3 grams, tartaric acid are that the mixed liquor of 5 grams, isopropyl three (dioctyl phosphinylidyne) titanate esters and tristerin is 5 grams, all the other prescriptions, reaction condition and step are with embodiment 1, and the result gets the conduction silver-plated copper powder of the uniform sandwich construction of 90.8 gram plating.The resistance value of this copper powder is with embodiment 1.
Embodiment 4
Prepare electrically-conducting paint with above-mentioned silver-plated copper powder by following proportioning:
100 parts of silver-plated copper powders
50～60 parts of 40% acrylic acid modified resins
2 parts of silicone couplet KH-550
20 parts of butyl acetates
20 parts of dimethylbenzene
10 parts of butanone
This electrically-conducting paint energy cold curing that sprays, its performance is as follows after tested:
Outward appearance: silver-colored dark brown viscous fluid
Viscosity: η
25 ℃=1.2Pas
Relative density: 1.8～2.0
Specific insulation≤5 * 10
-4Ω cm.
Adhesive force (to the adhesive force of ABS plate): O level
Surface resistivity :≤0.1 Ω/cm
2
Environment resistant: at 70 ℃, aging 100 hours, surface resistivity≤0.2 Ω/cm
2
At 40 ℃, relative humidity is 95% and aging 100 hours, surface resistivity≤
0．2Ω／cm
2。(the specimen area is effectiveness: 25 * 25cm
2):
Under 500 megahertzes, initial value is 57～60dB;
Be 95% and be 57～58dB under the situation in aging 100 hours at 40 ℃, relative humidity.
Claims (12)
1; a kind of preparation method of copper powder for electromagnetic shield conducting paint; it is characterized in that: in EDTA (EDTA) and sodium-salt aqueous solution thereof, add the thin copper powder of electrolysis; at 20～65 ℃; stir; then add silver nitrate aqueous solution; make copper displacement silver ion; allow silver be deposited on the surface of copper powder; add reductive acid then; micro silver ion in the reducing solution also is deposited on the copper powder trace silver, forms the silver-colored protective layer of one deck densification on the copper powder surface; above-mentioned reactant liquor after filtration; the silver-plated copper powder that obtains after the drying is handled with the organic acid ester mixed solution, makes anti-oxidant; the conduction silver-plated copper powder of sandwich construction.
2, the preparation method of copper powder as claimed in claim 1 is characterized in that: EDTA and sodium salt thereof are that selection is a kind of arbitrarily from EDTA and single sodium salt, disodium salt and trisodium salt.
3, the preparation method of copper powder as claimed in claim 2 is characterized in that: EDTA and sodium salt thereof are EDTA and disodium salt thereof, and its consumption is 1～6% of a copper powder weight.
4, the preparation method of copper powder as claimed in claim 3 is characterized in that: the consumption of EDTA and disodium salt thereof is 2～4% of a copper powder weight.
5, the preparation method of copper powder as claimed in claim 1 is characterized in that: the silver nitrate consumption is 1.5～8.0% of a copper powder weight.
6, the preparation method of copper powder as claimed in claim 1 is characterized in that: reductive acid is that selection is a kind of arbitrarily from tartaric acid, oxalic acid, and its consumption is 1～5% of a copper powder weight.
7, the preparation method of copper powder as claimed in claim 6 is characterized in that: reductive acid is a tartaric acid, and its consumption is 1～5% of a copper powder weight.
8, the preparation method of copper powder as claimed in claim 1, it is characterized in that: the organic acid ester mixed solution is the mixture of titanate esters and fatty acid ester, the mixed proportion of titanate esters and fatty acid ester is between 20: 80～80: 20, and their total additions are 2～8% of copper powder weight.
9, the preparation method of copper powder as claimed in claim 8 is characterized in that: the mixed proportion of titanate esters and fatty acid ester is between 20: 80～80: 20, and their total additions are 2～5% of copper powder weight.
10, the preparation method of copper powder as claimed in claim 8 is characterized in that: titanate esters be have select in the ester class of following general formula a kind of,
(RO)
x-Ti-(OR’)
4-x
Wherein RO is that R is C
2～C
4The hydrophilic radical of carbochain, OR ' are that R ' is C
8～C
13The lipophile group of carbochain, X are the integer between 1～3,
Fatty acid ester is C
8～C
18High-grade aliphatic ester.
11, the preparation method of copper powder as claimed in claim 10 is characterized in that: described fatty acid ester is a tristerin.
12, the preparation method of copper powder as claimed in claim 10 is characterized in that: described fatty acid ester is an isopropyl stearate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95111554 CN1061579C (en) | 1995-03-08 | 1995-03-08 | Process for preparing copper powder for electromagnetic shield conducting paint |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 95111554 CN1061579C (en) | 1995-03-08 | 1995-03-08 | Process for preparing copper powder for electromagnetic shield conducting paint |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1130553A CN1130553A (en) | 1996-09-11 |
| CN1061579C true CN1061579C (en) | 2001-02-07 |
Family
ID=5078830
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 95111554 Expired - Lifetime CN1061579C (en) | 1995-03-08 | 1995-03-08 | Process for preparing copper powder for electromagnetic shield conducting paint |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1061579C (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4389148B2 (en) * | 2002-05-17 | 2009-12-24 | 日立化成工業株式会社 | Conductive paste |
| CN1315604C (en) * | 2003-11-08 | 2007-05-16 | 桂林工学院 | Chemical Preparation for sheet superfine copper powder |
| CN100400708C (en) * | 2004-05-25 | 2008-07-09 | 桂林工学院 | A method for preparing silver plated copper powder |
| CN100418394C (en) * | 2006-09-14 | 2008-09-10 | 同济大学 | Inorganic non-metallic conductivity, electromagnetic shielding powder and method for making same and application |
| CN100493781C (en) * | 2007-04-06 | 2009-06-03 | 深圳市危险废物处理站 | Method of producing sheet shaped silver-plated copper powder |
| CN101887767B (en) * | 2010-06-11 | 2011-08-17 | 山东大学 | Method for preparing conductive paste by taking copper powder with surface coverage silver nanostructures as packing |
| CN101905321B (en) * | 2010-08-20 | 2011-11-16 | 中国兵器工业集团第五三研究所 | Preparation method of flake silver-plated copper powder |
| CN103128308B (en) * | 2013-03-06 | 2014-10-29 | 东南大学 | Method for preparing compact silver-coated copper powder by using one pot method |
| CN103396711A (en) * | 2013-06-26 | 2013-11-20 | 南京市荣达树脂有限公司 | Preparation method of conductive resin coating |
| CN103360879A (en) * | 2013-06-26 | 2013-10-23 | 南京市荣达树脂有限公司 | Conductive resin coating |
| BR112016024827A2 (en) * | 2014-04-23 | 2017-08-15 | Alpha Metals | method for making metal powder |
| CN103920876B (en) * | 2014-05-07 | 2016-08-24 | 南京宜洛辞电子科技有限公司 | A kind of resistant to elevated temperatures high connductivity silver-coated copper powder and preparation method thereof |
| JP6368925B2 (en) * | 2014-10-01 | 2018-08-08 | 協立化学産業株式会社 | Coated copper particles and method for producing the same |
| CN104530873A (en) * | 2014-12-30 | 2015-04-22 | 西安泰力松新材料股份有限公司 | Copper-based electromagnetic shielding coating and preparation method thereof |
| CN111587056A (en) * | 2020-05-14 | 2020-08-25 | 湖南省国银新材料有限公司 | Electromagnetic shielding silver paste for communication equipment and preparation method thereof |
-
1995
- 1995-03-08 CN CN 95111554 patent/CN1061579C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| CN1130553A (en) | 1996-09-11 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
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| CX01 | Expiry of patent term |
Expiration termination date: 20150308 Granted publication date: 20010207 |