TW201306967A - Silver powder and method for producing same - Google Patents

Silver powder and method for producing same Download PDF

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TW201306967A
TW201306967A TW101121743A TW101121743A TW201306967A TW 201306967 A TW201306967 A TW 201306967A TW 101121743 A TW101121743 A TW 101121743A TW 101121743 A TW101121743 A TW 101121743A TW 201306967 A TW201306967 A TW 201306967A
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Taiwan
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silver
silver powder
paste
particles
powder
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TW101121743A
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Chinese (zh)
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TWI579073B (en
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Masahito Inoue
Yuji Kawakami
Tomomichi Nihei
Toshiaki Terao
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Sumitomo Metal Mining Co
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER
    • B22F9/00Making metallic powder or suspensions thereof
    • B22F9/16Making metallic powder or suspensions thereof using chemical processes
    • B22F9/18Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
    • B22F9/24Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER
    • B22F1/00Special treatment of metallic powder, e.g. to facilitate working, to improve properties; Metallic powders per se, e.g. mixtures of particles of different composition
    • B22F1/0003Metallic powders per se; Mixtures of metallic powders; Metallic powders mixed with a lubricating or binding agent
    • B22F1/0007Metallic powder characterised by its shape or structure, e.g. fibre structure
    • B22F1/0011Metallic powder characterised by size or surface area only
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER
    • B22F1/00Special treatment of metallic powder, e.g. to facilitate working, to improve properties; Metallic powders per se, e.g. mixtures of particles of different composition
    • B22F1/0081Special treatment of metallic powder, e.g. to facilitate working, to improve properties
    • B22F1/0096Treatment resulting in the production of agglomerates
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B22CASTING; POWDER METALLURGY
    • B22FWORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER
    • B22F1/00Special treatment of metallic powder, e.g. to facilitate working, to improve properties; Metallic powders per se, e.g. mixtures of particles of different composition
    • B22F1/02Special treatment of metallic powder, e.g. to facilitate working, to improve properties; Metallic powders per se, e.g. mixtures of particles of different composition comprising coating of the powder

Abstract

In order to provide a silver powder which has excellent compatibility with a solvent, a resin, etc. in a silver paste, and excellent dispersibility, and a method for producing the same, a silver powder according to the invention has an organic coating layer formed on the surface thereof and has an internal friction angle of 20 or less and a contact angle with an aqueous solution of 50 vol% methanol of 100 or more.

Description

銀粉及其製造方法 Silver powder and its manufacturing method
本發明為關於銀粉及其製造方法,更詳而言之為關於在電子機器之配線層或電極等之形成時,成為所利用的銀糊料(paste)之主成分的銀粉及其製造方法。 The present invention relates to a silver powder and a method for producing the same, and more particularly to a silver powder which is a main component of a used silver paste when a wiring layer or an electrode of an electronic device is formed, and a method for producing the same.
本申請案為基於在日本國於2011年6月16日所提出發明專利申請的日本專利申請號特願2011-134337,並主張其為優先權者,藉由參考此等申請案而援用於本申請案。 The present application is based on Japanese Patent Application No. 2011-134337, filed on Jun. Application.
如樹脂型銀糊料或煅燒型銀糊料般的銀糊料正廣泛地使用於電子機器之配線層或電極等之形成。將此等銀糊料塗布或印刷於各種基材上後,藉由加熱硬化或加熱煅燒而可形成成為配線層或電極等之導電膜。 A silver paste such as a resin type silver paste or a calcined silver paste is widely used for formation of a wiring layer or an electrode of an electronic device. After the silver paste is applied or printed on various substrates, a conductive film such as a wiring layer or an electrode can be formed by heat curing or heating and firing.
例如,樹脂型銀糊料為由銀粉、樹脂、硬化劑、溶劑等所成,印刷於導電體電路圖型或端子上,以100℃~200℃使加熱硬化來製成導電膜,而形成配線層或電極。 For example, the resin type silver paste is made of silver powder, a resin, a curing agent, a solvent, etc., and is printed on a conductor pattern or a terminal, and is heat-hardened at 100 ° C to 200 ° C to form a conductive film to form a wiring layer. Or electrode.
又,煅燒型銀糊料為由銀粉、玻璃、溶劑等所成,印刷於導電體電路圖型或端子上後,以600℃~800℃加熱煅燒來製成導電膜,而形成配線層或電極。 Further, the calcined silver paste is formed of silver powder, glass, solvent, or the like, and is printed on a conductor pattern or a terminal, and then fired at 600 ° C to 800 ° C to form a conductive film to form a wiring layer or an electrode.
以此等銀糊料所形成的配線層或電極,係藉由銀粉之連接而形成電氣接續的電流路徑。 The wiring layer or the electrode formed by the silver paste is formed by the connection of the silver powder to form an electrically connected current path.
此等銀糊料中所使用的銀粉,粒徑為0.1μm至數 μm,依照形成的配線層寬度或電極厚度等,所使用的銀粉之粒徑會有所不同。又,藉由使銀粉均勻地分散於銀糊料中,可形成均勻寬度的配線層、均勻厚度的電極。 The silver powder used in these silver pastes has a particle size of 0.1 μm to several Μm, the particle size of the silver powder used may vary depending on the width of the wiring layer or the thickness of the electrode formed. Further, by uniformly dispersing the silver powder in the silver paste, a wiring layer having a uniform width and an electrode having a uniform thickness can be formed.
一般而言,製造銀糊料之方法,係將各構成要素計量並置入於指定的容器,使用萬能攪拌器或揉合機等進行預備混練後,再使用三軸輥等進行主混練。在預備混練,使各構成要素彼此充分地潤濕並分散為重要的,藉由充分地進行此預備混練,以防止在主混練之銀箔之產生,並使銀糊料中銀粉之粒度迅速地降低至目的之粒度,使銀粉在銀糊料中之均勻分散成為可能的。 In general, a method of producing a silver paste is to measure and place each component in a predetermined container, and perform preliminary kneading using a universal stirrer or a kneading machine, and then perform main kneading using a triaxial roll or the like. In the preliminary kneading, it is important to sufficiently wet and disperse the respective constituent elements, and the preliminary kneading is sufficiently performed to prevent the occurrence of the silver foil in the main kneading, and the particle size of the silver powder in the silver paste is rapidly lowered. The particle size to the purpose makes it possible to uniformly disperse the silver powder in the silver paste.
因此,對於在銀糊料中為佔據大部分重量之銀粉,要求著不僅是粒徑為均勻且凝聚為少,亦對於由溶劑或樹脂等所構成的媒液(vehicle)為混合良好、在銀糊料中之分散性高等之特性。如此般之特性,不僅會因為體密度或粒度分布等粉體之結構性性質,亦會因為粉體表面之滑動容易性或親水性、疏水性等銀粉表面之化學性質而變化。 Therefore, in the silver paste, it is required that not only the particle diameter is uniform but also agglomerated, and the vehicle is composed of a solvent or a resin, and the mixture is good in silver. The characteristics of high dispersibility in the paste. Such characteristics are not only due to the structural properties of the powder such as bulk density or particle size distribution, but also due to the sliding property of the powder surface or the chemical nature of the surface of the silver powder such as hydrophilicity and hydrophobicity.
關於銀糊料中所使用的銀粉,例如在專利文獻1中記載著,球狀銀粉為藉由具有特定的體密度以及成形體密度,而與媒液或樹脂之相溶性成為良好者。然而,在專利文獻1中未記載有關表面化學性質,僅以如此般之結構性參數來控制與媒液或樹脂之相溶性為困難的。又,專利文獻1中關於銀粉之製造方法,並未記載銀粉之壓碎方法等之製造方法(係對於上述表面化學性質為具有大影響者)。 In the case of the silver powder used in the silver paste, for example, Patent Document 1 discloses that the spherical silver powder has a specific bulk density and a molded body density, and the compatibility with the vehicle liquid or the resin is good. However, Patent Document 1 does not describe surface chemistry, and it is difficult to control the compatibility with a vehicle or a resin only by such a structural parameter. Further, in the method for producing silver powder in Patent Document 1, there is no description of a production method such as a crushing method of silver powder (which has a large influence on the surface chemistry described above).
另一方面,在專利文獻2中記載著,將藉由粒度分布 測定的D50值與藉由圖像解析所得到的粒徑DIA之比D50/DIA,作為粉體之凝聚度之基準,只要此為特定值以下時,則為低凝聚性。的確,當此值越小時,吾人係認知粉體中的凝聚體數為越少。然而,專利文獻2中亦與專利文獻1相同地,對於在糊料化時會影響與媒液或樹脂之相溶性之銀粉之表面化學性質相關之記載,或會影響化學性質之製造方法相關之記載,皆未有揭示。 On the other hand, Patent Document 2 describes that the particle size distribution will be adopted. The ratio D50/DIA of the measured D50 value to the particle diameter DIA obtained by image analysis is the basis of the degree of aggregation of the powder, and if it is below a specific value, it is low in cohesiveness. Indeed, the smaller the value, the less the number of aggregates in the cognitive powder. However, in Patent Document 2, similarly to Patent Document 1, the description relates to the description of the surface chemistry of the silver powder which affects the compatibility with the vehicle liquid or the resin during the paste formation, or the manufacturing method which affects the chemical properties. The records have not been revealed.
對於使用於銀糊料之銀粉,如專利文獻1或專利文獻2般之體密度或成形體密度、粉體之凝聚度等,僅以結構性質時無法充分地改善銀糊料之與溶劑或樹脂等之相溶性、分散性。因此,對於銀粉要求著相溶性及分散性之進一步的提昇。 For the silver powder used in the silver paste, the bulk density, the density of the molded body, the degree of aggregation of the powder, etc., as in Patent Document 1 or Patent Document 2, cannot sufficiently improve the silver paste with the solvent or the resin only in terms of structural properties. Such as compatibility and dispersibility. Therefore, further improvement in compatibility and dispersibility is required for the silver powder.
[先前技術文獻] [Previous Technical Literature] [專利文獻] [Patent Literature]
[專利文獻1]日本國特開2006-097086公報 [Patent Document 1] Japanese Patent Publication No. 2006-097086
[專利文獻2]日本國特開2004-100013公報 [Patent Document 2] Japanese Patent Publication No. 2004-100013
在此,本發明係有鑑於上述以往之事情者,以提供與銀糊料之溶劑或樹脂等之相溶性及分散性為優異的銀粉及其製造方法為目的。 In view of the above-described conventional matters, the present invention has an object of providing a silver powder excellent in compatibility and dispersibility with a solvent or a resin of a silver paste, and a method for producing the same.
達成上述目的之本發明相關的銀粉,其特徵係內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為100°以上。 The silver powder according to the present invention which achieves the above object is characterized in that the internal friction angle is 20 or less, and the contact angle in the methanol 50% by volume aqueous solution is 100 or more.
達成上述目的之本發明相關的銀粉之製造方法,其特徵係藉由對於銀粒子進行表面處理,在表面形成有機皮膜層後,以不對於有機被膜層造成損傷之程度充分地進行壓碎處理。 A method for producing a silver powder according to the present invention which achieves the above object is characterized in that, by subjecting silver particles to a surface treatment, an organic film layer is formed on the surface, and then the crushing treatment is sufficiently performed so as not to cause damage to the organic film layer.
本發明係藉由銀粉之內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為100°以上,而與溶媒或樹脂等之相溶性為高、分散性優異,且為可容易糊料化者。藉此,本發明可提昇銀糊料之品質及生產性。 In the present invention, the internal friction angle of the silver powder is 20° or less, and the contact angle of the 50% by volume aqueous solution of methanol is 100° or more, and the compatibility with the solvent or the resin is high, and the dispersibility is excellent, and the dispersibility is easy. Paste. Thereby, the present invention can improve the quality and productivity of the silver paste.
《實施發明之形態》 "Formation of Inventions"
以下,對於本發明所適用的銀粉及其製造方法進行詳細說明。尚,未有特別限定,本發明並不限定於以下詳細之說明。 Hereinafter, the silver powder to which the present invention is applied and a method for producing the same will be described in detail. Further, the present invention is not particularly limited, and the present invention is not limited to the following detailed description.
圖1所示之銀粉1,係含有於由硬化劑、樹脂、溶劑等所構成的樹脂型銀糊料或由玻璃、溶劑等所構成的煅燒型銀糊料中。含有銀粉1的樹脂型銀糊料或煅燒型銀糊料,為使用於配線層或電極之形成。因此,為試圖電氣接續般地,銀粉1必須與銀糊料之溶劑或樹脂為相溶性良好, 且均勻地分散於糊料中。銀粉1特別適合於使用疏水性溶劑之銀糊料。 The silver powder 1 shown in Fig. 1 is contained in a resin type silver paste composed of a curing agent, a resin, a solvent, or the like, or a calcined silver paste composed of glass, a solvent, or the like. The resin type silver paste or the calcined type silver paste containing the silver powder 1 is used for formation of a wiring layer or an electrode. Therefore, in order to attempt to electrically continue, the silver powder 1 must have good compatibility with the solvent or resin of the silver paste. And uniformly dispersed in the paste. Silver powder 1 is particularly suitable for use with a silver paste of a hydrophobic solvent.
銀粉1為內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為100°以上。更,銀粉1較佳為藉由丙酮滴定法之表面SP值為18以下。此銀粉1為藉由將粉體之表面化學性質設定為低親水性而改善滑動,而為與銀糊料之溶劑或樹脂等媒液之相溶性為良好者。尚,所謂的銀粉1,除了一次粒子以外,亦設定為包含二次粒子及凝聚體者。在此,如圖1(A)所示般,所謂的一次粒子,係指個別的球狀銀粒子2;如圖1(B)所示般,將藉由融著、固著等而一次粒子為複數連結的銀粒子2稱為二次粒子。 如圖1(C)所示般,將此等一次粒子或二次粒子之銀粒子2為凝聚者稱為凝聚體。 The silver powder 1 has an internal friction angle of 20 or less, and has a contact angle of 100 or more in a 50% by volume aqueous solution of methanol. Further, the silver powder 1 preferably has a surface SP value of 18 or less by acetone titration. The silver powder 1 is improved in sliding by setting the surface chemical property of the powder to a low hydrophilicity, and is compatible with a solvent such as a solvent or a resin of a silver paste. In addition, the so-called silver powder 1 is also set to include secondary particles and aggregates in addition to primary particles. Here, as shown in FIG. 1(A), the primary particles refer to individual spherical silver particles 2; as shown in FIG. 1(B), primary particles are bonded by fusion or fixation. The silver particles 2 connected in plurality are referred to as secondary particles. As shown in FIG. 1(C), the primary particles or the secondary particles of the silver particles 2 are aggregated and referred to as aggregates.
銀粉1,一次粒子之平均粒徑較佳為0.1μm~1.5μm之範圍。藉由一次粒子之平均粒徑為0.1μm以上,在製成銀糊料(導電性糊料)時,不會產生電阻,可使成為導電性良好者。又,藉由設定一次粒子之平均粒徑為1.5μm以下,不會使分散性惡化,在混練之際不會產生銀薄片(flake),亦可使印刷性成為良好。一次粒子之平均粒徑可藉由掃瞄型電子顯微鏡(SEM)觀察來進行測定。又,銀粉1之粒度,使用雷射繞射散射法所測定的D50(體積累積50%徑),較佳為0.5μm~5μm,更佳為1.0μm~4.0μm。藉由將D50設定為此範圍係成為作為銀糊料用為最佳者,內部摩擦角為最適化,可改善在糊料中之 分散性。 In the silver powder 1, the average particle diameter of the primary particles is preferably in the range of 0.1 μm to 1.5 μm. When the average particle diameter of the primary particles is 0.1 μm or more, when a silver paste (conductive paste) is produced, electric resistance is not generated, and it is possible to obtain conductivity. In addition, by setting the average particle diameter of the primary particles to 1.5 μm or less, the dispersibility is not deteriorated, and silver flakes are not generated during kneading, and the printability is also improved. The average particle diameter of the primary particles can be measured by scanning electron microscope (SEM) observation. Further, the particle size of the silver powder 1 is D50 (volume accumulation 50% diameter) measured by a laser diffraction scattering method, preferably 0.5 μm to 5 μm, more preferably 1.0 μm to 4.0 μm. By setting D50 to this range, it is the best for use as a silver paste, and the internal friction angle is optimized to improve the paste. Dispersibility.
所謂的銀粉1之內部摩擦角,為表示粉體之滑動容易性之參數,可藉由市售的粉體層剪切力測定裝置來進行測定。銀糊料用之銀粉1時,當內部摩擦角超過20°時,粒子(係在銀粉1中獨立存在的一次粒子、二次粒子或凝聚體)間之滑動會變差。其結果,在進行糊料化時,溶劑或樹脂無法進入到銀粉1之粒子間,而變得只能將銀粉1之表面之一部份潤濕而已。如此般之狀態時,即使是進行攪拌,粒子彼此亦不易分解,而銀粉1之分散性變為差者。分散性為差的銀粉1,在將各構成要素彼此潤濕並使分散之預備混練時不僅需花費時間,在藉由三軸輥摩機等之主混練時,凝聚的銀粉1亦會被壓壞而變得容易產生銀薄片。因此,銀粉1為藉由內部摩擦角為20°以下,而滑動變得良好,溶劑或樹脂會進入到粒子間,由於相溶性變得良好,故銀糊料中之分散性變得良好。 The internal friction angle of the silver powder 1 is a parameter indicating the easiness of sliding of the powder, and can be measured by a commercially available powder layer shear force measuring device. In the case of silver powder 1 for silver paste, when the internal friction angle exceeds 20°, the sliding between the particles (primary particles, secondary particles or aggregates which are independently present in the silver powder 1) is deteriorated. As a result, when the paste is formed, the solvent or the resin cannot enter between the particles of the silver powder 1, and only one part of the surface of the silver powder 1 can be wetted. In such a state, even if stirring is performed, the particles are not easily decomposed, and the dispersibility of the silver powder 1 is deteriorated. In the case of the silver powder 1 having poor dispersibility, it takes time not only to wet the components but also to prepare for the dispersion, and the coagulated silver powder 1 is also pressed when the main mixing is performed by a triaxial roll machine or the like. It is easy to produce silver flakes. Therefore, the silver powder 1 has an internal friction angle of 20 or less, and the sliding property is good, and the solvent or the resin enters between the particles, and since the compatibility is good, the dispersibility in the silver paste is good.
又,銀粉1在製造後當下,內部摩擦角當然為20°以下,較佳為即使是在製造後內部摩擦角亦維持在20°以下,且即使是在混合至溶劑或樹脂中來進行糊料化之際,亦為20°以下。例如,在製造銀粉1之後,即使是經過例如室溫1個月後,銀粉1之內部摩擦角亦為20°以下。內部摩擦角為因為粒子之凝聚而變化之參數,在製造後當下即使是凝聚程度為低之粉體,藉由粒子間之經時性凝聚之進行,內部摩擦角亦有變大之情形。當經時性變化而內部摩擦角為超過20°時,進行糊料化時分散性會降低,而銀粉 1會引起凝聚等各式各樣之問題。在此,只要能維持20°以下的內部摩擦角,由於可抑制凝聚之進行,故可防止糊料化之際問題之產生。 Further, the silver powder 1 is, after the manufacture, the internal friction angle is of course 20 or less, and it is preferable that the internal friction angle is maintained at 20 or less even after the production, and the paste is mixed even in a solvent or a resin. At the time of the transformation, it is also below 20°. For example, after the silver powder 1 is produced, even after passing through, for example, room temperature for one month, the internal friction angle of the silver powder 1 is 20 or less. The internal friction angle is a parameter which changes due to the aggregation of the particles. Even after the production, even if the powder has a low degree of aggregation, the internal friction angle is also increased by the temporal cohesion between the particles. When the internal friction angle is more than 20° over time, the dispersibility is lowered when the paste is formed, and the silver powder is lowered. 1 will cause a variety of problems such as cohesion. Here, as long as the internal friction angle of 20° or less can be maintained, since the progress of aggregation can be suppressed, it is possible to prevent the occurrence of problems during the paste formation.
接著,對於銀粉1之接觸角進行說明。銀粉1為在甲醇50容量%水溶液之接觸角為100°以上。接觸角為表示:銀粉1之表面之相對於溶劑之潤濕容易性之參數,例如,當相對於水之接觸角越大時,變得越容易被疏水性糊料溶劑潤濕。相反地,當相對於水之接觸角越小時,越為親水性,相對於疏水性糊料溶劑之潤濕會變差。銀粉1之接觸角,一般為在已成形的表面上來進行測定,惟當以水進行測定時,疏水性為大之粉體時,水滴在成形粉體之表面上會成為真圓狀,由於水滴會滑動而難以精準地進行計測。因此,係進行著將甲醇等極性為低之溶媒添加於水中,將溶媒之極性降低來進行測定之方法。在製作銀糊料之際,一般大多使用疏水性之溶劑。因此,當銀粉1為具有接觸角為未滿100°之親水性表面時,糊料之相對於溶劑或樹脂之相溶性為差,銀粉1與溶劑或樹脂無法產生潤濕,而進行糊料化會變得困難。又,強行予以混練進行糊料化時,由於分散安定性差而再凝聚,變得容易產生糊料之分離。 Next, the contact angle of the silver powder 1 will be described. The silver powder 1 has a contact angle of 100° or more in a 50% by volume aqueous solution of methanol. The contact angle is a parameter indicating the ease of wetting of the surface of the silver powder 1 with respect to the solvent, for example, the larger the contact angle with respect to water, the easier it is to be wetted by the hydrophobic paste solvent. Conversely, the smaller the contact angle with respect to water, the more hydrophilic it is, and the wetting with respect to the hydrophobic paste solvent is deteriorated. The contact angle of the silver powder 1 is generally measured on the surface to be formed. However, when the water is a large powder when measured by water, the water droplets become a true round shape on the surface of the formed powder due to water droplets. It will slide and it is difficult to measure accurately. Therefore, a method in which a solvent having a low polarity such as methanol is added to water and the polarity of the solvent is lowered is measured. At the time of making a silver paste, a hydrophobic solvent is generally used. Therefore, when the silver powder 1 is a hydrophilic surface having a contact angle of less than 100°, the compatibility of the paste with respect to the solvent or the resin is poor, and the silver powder 1 does not wet with the solvent or the resin, and is paste-formed. It will become difficult. Further, when the paste is forcibly mixed and re-agglomerated due to poor dispersion stability, separation of the paste is likely to occur.
接著,對於銀粉1之表面SP值進行說明。銀粉1之表面SP值為18以下。表面SP值為表示銀粉1之表面極性之參數,越小時越為疏水性,越大時越為親水性。 Next, the surface SP value of the silver powder 1 will be described. The surface SP value of the silver powder 1 is 18 or less. The surface SP value is a parameter indicating the surface polarity of the silver powder 1, and the hydrophobicity is obtained as the case is smaller, and the hydrophilicity is made as the case is larger.
此表面SP值可使用市售的粉體潤濕性試驗機等進行 測定,簡易地使用如「色材、62(9)524-528」中所記載般的丙酮滴定法亦能測定。此丙酮滴定法時,係將疏水性粉體加入於水(A〔ml〕)中並使浮游。使用攪拌器緩慢地攪拌,同時以滴定管滴下丙酮,計測直到粉體為潤濕且沈降為止所需要的丙酮之滴下量(B〔ml〕)。水之SP值為23.43,丙酮之SP值為9.75,由使用的水之體積及使用的丙酮之體積,藉由下述式1來計算沈降的丙酮溶液之SP值,並將此值設定為銀粉1之表面SP值。 The surface SP value can be measured using a commercially available powder wettability tester or the like. The measurement can be carried out simply by using an acetone titration method as described in "Color material, 62 (9) 524-528". In this acetone titration method, a hydrophobic powder is added to water (A [ml]) and floated. The mixture was slowly stirred using a stirrer while dropping acetone in a burette, and the amount of acetone (B [ml]) required until the powder was wetted and settled was measured. The SP value of water is 23.43, and the SP value of acetone is 9.75. From the volume of water used and the volume of acetone used, the SP value of the settled acetone solution is calculated by the following formula 1, and this value is set as silver powder. 1 surface SP value.
銀粉1之表面SP值若較18為大時,親水性會過大,糊料之相對於溶劑或樹脂之相溶性會變差,銀粉1與溶劑或樹脂無法產生潤濕,而糊料化變得困難。又,即使是強行地予以混練進行糊料化,亦因為分散安定性為差而再凝聚,變得容易產生糊料之分離。另一方面,藉由銀粉1之表面SP值為18以下,銀粉1之親水性不會變得過大,與溶劑或樹脂之相溶性變得良好,由於成為分散性優異者,故糊料化變得容易。 When the surface SP value of the silver powder 1 is larger than 18, the hydrophilicity is too large, the compatibility of the paste with respect to the solvent or the resin is deteriorated, and the silver powder 1 and the solvent or the resin are not wetted, and the paste becomes difficult. Further, even if the paste is forcibly kneaded, the dispersion stability is re-agglomerated, and the separation of the paste is likely to occur. On the other hand, when the surface SP value of the silver powder 1 is 18 or less, the hydrophilicity of the silver powder 1 does not become excessively large, and the compatibility with a solvent or a resin becomes good, and the dispersibility is excellent, so the paste is changed. It's easy.
銀粉1係將藉由濕式還原法所得到的銀粒子2進行表面處理,如圖1般地,藉由在一次粒子或二次粒子之表面形成有機被膜層3,可使上述內部摩擦角為20°以下,且將在甲醇50容量%水溶液之接觸角設定為100°以上,更,亦可將藉由丙酮滴定法之表面SP值設定為18以下。此 有機被膜層3可藉由界面活性劑或界面活性劑及分散劑而予以形成。 The silver powder 1 is subjected to surface treatment by the silver particles 2 obtained by the wet reduction method. As shown in FIG. 1, by forming the organic film layer 3 on the surface of the primary particles or secondary particles, the internal friction angle can be made The contact angle of the 50% by volume aqueous solution of methanol is set to 100° or more, and the surface SP value by the acetone titration method may be set to 18 or less. this The organic film layer 3 can be formed by a surfactant, a surfactant, and a dispersing agent.
有機被膜層3較佳為藉由界面活性劑及分散劑所形成。銀粉1時,雖然藉由以電離狀態來使界面活性劑吸附於銀粒子2可抑制凝聚,惟,僅以界面活性劑來抑制凝聚時,添加量會變得過多。因此,即使在銀糊料中可得到良好的分散狀態,配線層或電極之導電性亦有不充分之情形。在此,為了使成為抑制銀粉1之凝聚且為配線層或電極之導電性充分者,併用界面活性劑與分散劑為有效的。 The organic film layer 3 is preferably formed by a surfactant and a dispersing agent. In the case of the silver powder 1, the aggregation of the surfactant is suppressed by the adsorption of the surfactant to the silver particles 2 in the ionized state. However, when the aggregation is suppressed only by the surfactant, the amount of addition is excessive. Therefore, even if a good dispersion state is obtained in the silver paste, the conductivity of the wiring layer or the electrode may be insufficient. Here, in order to suppress the aggregation of the silver powder 1 and to make the conductivity of the wiring layer or the electrode sufficient, it is effective to use a surfactant and a dispersant in combination.
有機被膜層3係藉由在界面活性劑之對於銀粒子2之吸附時或吸附後再添加分散劑,特佳為進而使分散劑形成於已吸附於銀粒子2的界面活性劑上。透過使分散劑藉由界面活性劑而吸附於銀粒子2之表面來形成有機被膜層3,除了有機被膜層3會強力地附著於銀粒子2之表面外,亦會變得與溶劑或樹脂之相溶性為良好者。藉此,即使是將銀粉1(係銀粒子2之表面為形成有幾乎一樣的有機被膜層3者)混合於溶劑或樹脂中,亦可抑制有機被膜層3之剝離等。 The organic film layer 3 is preferably formed by dispersing a dispersing agent at the time of adsorbing or adsorbing the silver particles 2 of the surfactant, and further forming a dispersing agent on the surfactant adsorbed on the silver particles 2. The organic film layer 3 is formed by adsorbing the dispersant on the surface of the silver particles 2 by the surfactant, and the organic film layer 3 is strongly adhered to the surface of the silver particles 2, and becomes a solvent or a resin. The compatibility is good. By this means, even if the silver powder 1 (the surface of the silver particles 2 is formed with almost the same organic film layer 3) is mixed in a solvent or a resin, peeling of the organic film layer 3 or the like can be suppressed.
例如,將氯化銀作為起始原料之銀粉1時,作為界面活性劑較佳為使用陽離子系界面活性劑。由於陽離子系界面活性劑不會受到pH之影響而會電離成正離子,故可得到對於銀粉1之吸附性之改善效果。 For example, when silver powder 1 containing silver chloride as a starting material is used, a cationic surfactant is preferably used as the surfactant. Since the cationic surfactant is ionized into a positive ion without being affected by the pH, the effect of improving the adsorption property of the silver powder 1 can be obtained.
陽離子系界面活性劑未特別限定者,較佳選自於以單烷基胺鹽所代表的烷基單胺鹽型;以N-烷基(C14~C18 )丙二胺二油酸鹽所代表的烷基二胺鹽型;以烷基三甲基氯化銨所代表的烷基三甲基銨鹽型;以棕櫚烷基二甲基苄基氯化銨所代表的烷基二甲基苄基銨鹽型;以烷基二聚氧乙烯甲基氯化銨所代表的4級銨鹽型;以烷基砒啶鹽型、二甲基硬脂胺所代表的3級胺型;以聚氧丙烯.聚氧乙烯烷基胺所代表的聚氧乙烯烷基胺型;以N,N’,N’-參(2-羥基乙基)-N-烷基(C14~18)1,3-二胺基丙烷所代表的二胺之氧乙烯加成型之至少1種,更佳為4級銨鹽型、3級胺鹽型之任一者或其混合物。 The cationic surfactant is not particularly limited, and is preferably selected from the group consisting of alkyl monoamine salts represented by monoalkylamine salts; and N-alkyl groups (C14 to C18). An alkyl diamine salt type represented by propylene diamine dioleate; an alkyl trimethyl ammonium salt type represented by alkyl trimethyl ammonium chloride; chlorinated with palm alkyl dimethyl benzyl An alkyl dimethyl benzyl ammonium salt type represented by ammonium; a 4-grade ammonium salt type represented by an alkyl dimer oxyethylene methyl ammonium chloride; an alkyl acridine salt type, dimethyl stearylamine The 3-grade amine type represented by polyoxypropylene. a polyoxyethylene alkylamine type represented by a polyoxyethylene alkylamine; a N,N',N'-parade (2-hydroxyethyl)-N-alkyl (C14-18) 1,3-diamine At least one of the oxyethylene addition molding of the diamine represented by the propane is more preferably any one of a quaternary ammonium salt type and a ternary amine salt type or a mixture thereof.
又,陽離子系界面活性劑,較佳為至少具有1個以甲基、丁基、十六基、十八基、牛脂、硬化牛脂、植物系硬脂醯所代表具有C4~C36之碳數之烷基。作為烷基,較佳為將選自於聚氧乙烯、聚氧丙烯、聚氧乙烯聚氧丙烯、聚丙烯酸、聚羧酸之至少1種經加成者。由於此等烷基與作為分散劑所使用的脂肪酸之吸附為強,故藉由界面活性劑使分散劑吸附於銀粒子2時,可強力地吸附脂肪酸。 Further, the cationic surfactant preferably has at least one carbon number of C4 to C36 represented by methyl, butyl, hexadecyl, octadecyl, tallow, hardened tallow, and plant stearin. alkyl. The alkyl group is preferably one selected from the group consisting of polyoxyethylene, polyoxypropylene, polyoxyethylene polyoxypropylene, polyacrylic acid, and polycarboxylic acid. Since the adsorption of these alkyl groups with the fatty acid used as the dispersing agent is strong, when the dispersing agent is adsorbed to the silver particles 2 by the surfactant, the fatty acid can be strongly adsorbed.
陽離子系界面活性劑未特別限定者,但較佳為選自於氟化物、溴化物、碘化物、氯化物、硫酸鹽、硝酸鹽、磷酸鹽之至少1種。此等係一般含有作為界面活性劑之主成分,且容易取得,故宜。 The cationic surfactant is not particularly limited, but is preferably at least one selected from the group consisting of fluoride, bromide, iodide, chloride, sulfate, nitrate, and phosphate. These systems generally contain a main component as a surfactant and are easily available.
作為分散劑,可使用例如脂肪酸、有機金屬、明膠等之保護膠體,惟當考量未有雜質混入之虞且與界面活性劑之吸附性時,較佳為使用脂肪酸或該鹽。尚,脂肪酸或該鹽可作為乳液來進行添加。 As the dispersing agent, for example, a protective colloid such as a fatty acid, an organic metal or gelatin can be used. However, when it is considered that no impurities are mixed in and adsorbed with the surfactant, it is preferred to use a fatty acid or a salt. Still, the fatty acid or the salt can be added as an emulsion.
在作為分散劑所使用的脂肪酸方面,未有特別限定者,但較佳為選自於硬脂酸、油酸、肉豆蔻酸、棕櫚酸、亞麻油酸、月桂酸、次亞麻油酸之至少1種。此等脂肪酸由於沸點相對為低,因而對於使用銀糊料所形成的配線層或電極之不良影響為少。脂肪酸本來即為疏水性,係透過使分散劑藉由界面活性劑而吸附於銀粒子2之表面,而變成多數為存在於有機被膜層3之外面側,認為因而銀粉1會變得具有如疏水性般地。特別容易吸附於銀粒子2,例如,藉由選擇一界面活性劑,其係以電荷性為與銀粒子2表面為相反之電荷而會電離者,可使分散劑充分地藉由界面活性劑而吸附,銀粉1變得展現出充分的疏水性。 The fatty acid used as the dispersing agent is not particularly limited, but is preferably selected from at least stearic acid, oleic acid, myristic acid, palmitic acid, linoleic acid, lauric acid, and linoleic acid. 1 species. Since these fatty acids have a relatively low boiling point, there is little adverse effect on the wiring layer or the electrode formed using the silver paste. The fatty acid is inherently hydrophobic, and the dispersing agent is adsorbed on the surface of the silver particle 2 by the surfactant, and most of it is present on the outer surface side of the organic film layer 3, and it is considered that the silver powder 1 becomes hydrophobic as it is. Sexually. It is particularly easy to adsorb to the silver particles 2, for example, by selecting a surfactant which is ionized by a charge opposite to the surface of the silver particles 2, so that the dispersant can be sufficiently used by the surfactant. Adsorption, silver powder 1 becomes fully hydrophobic.
界面活性劑之添加量,較佳為相對於銀粒子2為0.002質量%~1.000質量%之範圍。由於幾乎全數量的界面活性劑會吸附於銀粒子2,故界面活性劑之添加量與吸附量幾乎會成為相等者。若界面活性劑之添加量未滿0.002質量%時,有無法得到抑制銀粒子2之凝聚或改善分散劑之吸附性效果之情形。另一方面,若添加量超過1.000質量%時,由於使用銀糊料所形成的配線層或電極之導電性會降低,故不宜。 The amount of the surfactant added is preferably in the range of 0.002% by mass to 1.000% by mass based on the silver particles 2. Since almost all of the surfactant is adsorbed to the silver particles 2, the amount of the surfactant added and the amount of adsorption are almost equal. When the amount of the surfactant added is less than 0.002% by mass, the aggregation of the silver particles 2 may be suppressed or the effect of improving the adsorptivity of the dispersant may not be obtained. On the other hand, when the amount added exceeds 1.000% by mass, the conductivity of the wiring layer or the electrode formed using the silver paste is lowered, which is not preferable.
分散劑之添加量,較佳為相對於銀粒子2為0.01質量%~3.00質量%之範圍,更佳為0.01質量%~1.00質量%。雖然依照分散劑之種類對於銀粒子2之吸附量會有所差異,但當添加量未滿0.01質量%時,銀粒子2為未吸附有能充分得到抑制銀粒子2之凝聚效果之量之分散劑 情形。另一方面,當分散劑之添加量超過3.00質量%時,吸附於銀粒子2的分散劑變多,使用銀糊料所形成的配線層或電極有無法充分得到導電性之情形。 The amount of the dispersant added is preferably in the range of 0.01% by mass to 3.00% by mass, more preferably 0.01% by mass to 1.00% by mass based on the silver particles 2. Although the amount of adsorption of the silver particles 2 varies depending on the type of the dispersing agent, when the amount added is less than 0.01% by mass, the silver particles 2 are dispersed without being adsorbed in an amount sufficient to suppress the aggregation effect of the silver particles 2. Agent situation. On the other hand, when the amount of the dispersant added exceeds 3.00% by mass, the amount of the dispersant adsorbed to the silver particles 2 increases, and the wiring layer or the electrode formed using the silver paste may not sufficiently obtain conductivity.
銀粉1為藉由使用陽離子系界面活性劑,由於大幅地改善界面活性劑之對於銀粒子2之吸附性,故可使界面活性劑堅固地吸附於銀粉1。更佳為藉由使吸附於銀粒子2的界面活性劑安定地吸附,可得到更進一步抑制凝聚且在糊料中之分散性為優異的銀粉1。 Since the silver powder 1 is a cationic surfactant, since the adsorbability of the surfactant to the silver particles 2 is greatly improved, the surfactant can be strongly adsorbed to the silver powder 1. More preferably, the adsorbent adsorbed on the silver particles 2 is stably adsorbed, whereby the silver powder 1 which further suppresses aggregation and is excellent in dispersibility in the paste can be obtained.
接著,對於本發明之銀粉1之製造方法,進行每步驟之說明。 Next, a description will be given of each step of the method for producing the silver powder 1 of the present invention.
銀粉1之製造方法,例如將氯化銀設定為起始原料時,如同以下。首先為進行以下之步驟:將銀錯合物溶液(其係藉由錯化劑將氯化銀溶解所得到的含有銀錯合物者)與還原劑溶液混合,並將銀錯合物還原,藉由使銀粒子2析出的濕式還原法而生成銀粒子漿料。在此生成銀粒子漿料之步驟,不需要設置:在將硝酸銀作為起始原料之以往方法中所必須的亞硝酸氣體之回收裝置或廢水中的硝酸系氮之處理裝置,亦由於對於環境之影響為少之製程,故可試圖製造成本之降低。 The method for producing the silver powder 1, for example, when silver chloride is used as a starting material, is as follows. First, the following steps are carried out: mixing a silver complex solution (which is obtained by dissolving silver chloride by a distoring agent) with a reducing agent solution, and reducing the silver complex. A silver particle slurry is produced by a wet reduction method in which silver particles 2 are deposited. In the step of producing a silver particle slurry, it is not necessary to provide a nitrous acid gas recovery device or a nitric acid nitrogen treatment device in a waste water in a conventional method using silver nitrate as a starting material, and also for the environment. The impact is a small process, so it is possible to try to reduce the manufacturing cost.
具體地,在生成銀粒子漿料之步驟時,首先,使用錯化劑溶解氯化銀,並調製含有銀錯合物之銀錯合物溶液。作為錯化劑未有特別限定者,較佳為使用容易與氯化銀形成錯合物,且不含作為雜質而殘留成分之氨水。又,氯化銀較佳為使用高純度者。作為如此般之氯化銀,純度 99.9999質量%之高純度氯化銀為可工業性安定製造。 Specifically, in the step of producing a silver particle slurry, first, silver chloride is dissolved using a distoring agent, and a silver complex solution containing a silver complex is prepared. The distorting agent is not particularly limited, and it is preferred to use ammonia water which is easily formed into a complex with silver chloride and which does not contain a component as an impurity. Further, it is preferred that silver chloride be used in a high purity. As such a silver chloride, purity 99.9999% by mass of high-purity silver chloride is industrially stable.
作為氯化銀等之溶解方法,例如作為錯化劑為使用氨水時,可在製作氯化銀之漿料後再添加氨水,為了提高錯合物濃度以提昇生產性,較佳為將氯化銀添加於氨水中進行溶解。溶解氯化銀之氨水,可使用一般工業用使用者,惟為了防止雜質混入,較佳為使用盡可能高純度之氨水。 As a method of dissolving silver chloride or the like, for example, when ammonia water is used as the distorting agent, ammonia water may be added after the slurry of silver chloride is produced, and in order to increase the concentration of the complex to improve productivity, chlorination is preferred. Silver is added to the ammonia water for dissolution. Ammonia water in which silver chloride is dissolved can be used by a general industrial user. However, in order to prevent impurities from being mixed, it is preferred to use ammonia water of the highest purity as possible.
接下來,調製與銀錯合物溶液混合的還原劑溶液。作為還原劑,一般可使用肼或福馬林等。由於抗壞血酸之還原作用緩慢,銀粒子2中的結晶粒容易成長,故特宜。由於肼或福馬林之還原力強,故銀粒子2中的結晶容易變小。又,為了控制反應之均勻性或反應速度,亦可將還原劑以純水等溶解或稀釋,以作為濃度調整過的水溶液使用。 Next, a reducing agent solution mixed with the silver complex solution is prepared. As the reducing agent, hydrazine or formalin or the like can be generally used. Since the reduction of ascorbic acid is slow, the crystal grains in the silver particles 2 tend to grow, which is particularly preferable. Since the reducing power of hydrazine or fumarin is strong, the crystal in the silver particles 2 tends to be small. Further, in order to control the uniformity of the reaction or the reaction rate, the reducing agent may be dissolved or diluted with pure water or the like to be used as a concentration-adjusted aqueous solution.
在進行還原反應之際,較佳為添加水溶性高分子。作為添加的水溶性高分子,未特別限定,較佳為聚環氧乙烷、聚乙二醇、聚乙烯醇或聚乙烯吡咯啶酮之至少1種。在將銀錯合物還原使銀粒子2析出之際,為了不使銀之一次粒子或二次粒子過度凝聚,水溶性高分子為吸附於銀粒子2之表面,並擔任使銀粒子2分散之分散劑的角色。未添加水溶性高分子時,因為銀錯合物之還原,產生的核或核為成長的銀粒子2會過度凝聚,故會成為分散性差者。即使是未添加水溶性高分子之情形,藉由還原條件,亦能將銀粉1之粒度調整至作為銀糊料用為較佳之程度,惟,藉由水溶性高分子之添加,可調整成作為銀糊料用為更佳之粒度。水溶性高分子之添加量,只要依照水溶性高分子之 種類及所欲得到銀粉1之粒徑予以適當地決定即可,相對於銀錯合物溶液中所含有的銀,較佳設定為1質量%~10質量%之範圍。藉由將水溶性高分子之含有量設定為1質量%~10質量%,不會產生銀之一次粒子或二次粒子之過度凝聚,於調整銀粉1之粒度之同時,在後續步驟中,可適度地將有機被膜層3形成於銀粒子2之表面。 When the reduction reaction is carried out, it is preferred to add a water-soluble polymer. The water-soluble polymer to be added is not particularly limited, and at least one of polyethylene oxide, polyethylene glycol, polyvinyl alcohol or polyvinylpyrrolidone is preferred. When the silver complex 2 is precipitated and the silver particles 2 are precipitated, the water-soluble polymer is adsorbed on the surface of the silver particles 2 so as not to disperse the primary particles or the secondary particles of silver, and the silver particles 2 are dispersed. The role of the dispersant. When the water-soluble polymer is not added, the silver or the nucleus which is produced by the reduction of the silver complex is excessively aggregated, and thus the dispersibility is poor. Even in the case where a water-soluble polymer is not added, the particle size of the silver powder 1 can be adjusted to a level suitable for use as a silver paste by reducing conditions, but it can be adjusted by addition of a water-soluble polymer. Silver paste is used for better particle size. The amount of water-soluble polymer added is as long as it is in accordance with water-soluble polymer The type and the particle size of the silver powder 1 to be obtained may be appropriately determined, and it is preferably in the range of 1% by mass to 10% by mass based on the silver contained in the silver complex solution. By setting the content of the water-soluble polymer to 1% by mass to 10% by mass, excessive aggregation of primary particles or secondary particles of silver does not occur, and the particle size of the silver powder 1 is adjusted, and in the subsequent step, The organic film layer 3 is formed on the surface of the silver particles 2 moderately.
水溶性高分子亦可添加於銀錯合物溶液及還原劑溶液之雙方或任一方中。關於水溶性高分子之添加於銀錯合物溶液及還原劑溶液之雙方或任一方中,可在還原處理之前事先添加於添加對象之溶液中,亦可在用於還原處理之將含銀錯合物溶液及還原劑溶液混合時進行添加。更佳為將水溶性高分子事先混合於還原劑溶液中放著。此情形係經實驗性所確認之結果,藉由將還原劑溶液與水溶性高分子混合放著,水溶性高分子會存在於核產生或核成長之場合,由於水溶性高分子會迅速地吸附於生成的核或銀粒子2之表面,故認為可抑制過度的凝聚。又,將水溶性高分子混合於銀錯合物溶液之際之濃度,更佳設定為超過3質量%、10質量%以下。將水溶性高分子事先添加於含銀錯合物溶液中時,水溶性高分子難以供給於核產生或核成長之場合,由於有無法使水溶性高分子適度地吸附於銀粒子2之表面之虞,故添加較3質量%為多。 The water-soluble polymer may be added to either or both of the silver complex solution and the reducing agent solution. The water-soluble polymer may be added to both the silver complex solution and the reducing agent solution in advance, or may be added to the solution to be added before the reduction treatment, or may be used in the reduction treatment. The compound solution and the reducing agent solution are added as they are mixed. More preferably, the water-soluble polymer is previously mixed in a reducing agent solution. This case is an experimentally confirmed result. By mixing the reducing agent solution with the water-soluble polymer, the water-soluble polymer may be present in the case of nuclear generation or nuclear growth, since the water-soluble polymer will rapidly adsorb. On the surface of the generated core or silver particles 2, it is considered that excessive aggregation can be suppressed. Moreover, the concentration at the time of mixing the water-soluble polymer in the silver complex solution is more preferably set to more than 3% by mass and not more than 10% by mass. When the water-soluble polymer is added to the silver-containing complex solution in advance, the water-soluble polymer is hardly supplied to the nucleus or the nucleus, and the water-soluble polymer is not able to be appropriately adsorbed on the surface of the silver particle 2 Oh, so add more than 3 mass%.
在添加水溶性高分子時,在還原反應時由於有發泡情形,故亦可於銀錯合物溶液或還原劑混合液中添加消泡劑。消泡劑未特別限定者,只要是通常還原時所使用者即可 。惟,為了不阻礙還原反應,消泡劑之添加量以能得到消泡效果之最小限度為佳。 When a water-soluble polymer is added, an antifoaming agent may be added to the silver complex solution or the reducing agent mixture because of foaming during the reduction reaction. The antifoaming agent is not particularly limited as long as it is a user who is usually reduced. . However, in order not to hinder the reduction reaction, the amount of the antifoaming agent added is preferably minimized to obtain a defoaming effect.
尚,關於在調製銀錯合物溶液及還原劑溶液之際所使用之水,為了防止雜質之混入,較佳使用雜質為已除去之水,特佳為使用純水。 Further, in order to prevent the incorporation of impurities in the water used for preparing the silver complex solution and the reducing agent solution, it is preferred to use the impurities as the removed water, and it is particularly preferable to use pure water.
在生成銀粒子漿料之步驟,將如上述般調製的銀錯合物溶液與還原劑溶液混合,以還原銀錯合物並使銀粒子2藉由濕式還原法析出。此還原反應可為分批法,或可使用如管式反應器法或溢流法般之連續還原法來進行。又,銀粒子2之粒徑,可藉由控制銀錯合物溶液與還原劑溶液之混合速度或銀錯合物之還原速度,可容易控制作為目的之粒徑。然後,將得到的銀粒子漿料使用過濾器等進行過濾,並將銀粒子2固液分離。 In the step of forming a silver particle slurry, the silver complex solution prepared as described above is mixed with a reducing agent solution to reduce the silver complex and precipitate the silver particles 2 by a wet reduction method. This reduction reaction can be carried out in a batch process or can be carried out using a continuous reduction process such as a tubular reactor process or an overflow process. Further, the particle diameter of the silver particles 2 can be easily controlled by controlling the mixing speed of the silver complex solution and the reducing agent solution or the reduction rate of the silver complex. Then, the obtained silver particle slurry is filtered using a filter or the like, and the silver particles 2 are solid-liquid separated.
以此步驟所得到的銀粒子2,表面會吸附著大量的氯離子及剩餘的水溶性高分子。因此,為了將使用銀糊料所形成的配線層或電極之導電性設定為足夠者,將得到的銀粒子2之漿料在接下來的洗淨步驟中進行洗淨,必須將此等表面吸附物藉由洗淨而予以除去。 The silver particles 2 obtained in this step have a large amount of chloride ions and the remaining water-soluble polymer adsorbed on the surface. Therefore, in order to set the conductivity of the wiring layer or the electrode formed using the silver paste to be sufficient, the obtained slurry of the silver particles 2 is washed in the subsequent washing step, and it is necessary to adsorb the surface. The matter is removed by washing.
作為洗淨方法未特別限定者,一般為使用將由漿料固液分離的銀粒子2投入於洗淨液中,使用攪拌機或超音波洗淨器攪拌後,再度進行固液分離將銀粒子2回收之方法。又,為了充分地除去表面吸附物,較佳為重複進行由投入於洗淨液中、攪拌洗淨及固液分離所構成之操作適當之數回。 The washing method is not particularly limited, and generally, the silver particles 2 separated from the slurry by solid-liquid separation are put into the washing liquid, stirred by a stirrer or an ultrasonic cleaner, and then subjected to solid-liquid separation to recover the silver particles 2 The method. Moreover, in order to sufficiently remove the surface adsorbate, it is preferable to repeat the operation which is performed by the washing liquid, the stirring washing, and the solid-liquid separation.
洗淨液可使用水,惟為了效率良好地除去氯,可使用鹼水溶液。作為鹼溶液未特別限定者,較佳使用殘留之雜質為少且廉價的氫氧化鈉水溶液。作為洗淨液若使用氫氧化鈉水溶液時,在使用氫氧化鈉水溶液之洗淨後為了除去鈉,宜將銀粒子2或該漿料進一步以水洗淨。 Water can be used as the washing liquid, but in order to remove chlorine efficiently, an aqueous alkali solution can be used. The alkali solution is not particularly limited, and it is preferred to use an anhydrous sodium hydroxide solution which is low in residual impurities. When a sodium hydroxide aqueous solution is used as the cleaning liquid, it is preferred to wash the silver particles 2 or the slurry with water in order to remove sodium after washing with an aqueous sodium hydroxide solution.
使用於洗淨的氫氧化鈉水溶液之濃度,較佳為0.01mol/l~1mol/l。若未滿0.01mol/l時,洗淨效果會不充足;若超過1mol/l時,會有容許值以上之鈉殘留於銀粒子2中之情形。尚,使用於洗淨液之水,較佳為未含有對於銀粒子2為有害之雜質元素,特佳為純水。 The concentration of the aqueous sodium hydroxide solution used for washing is preferably from 0.01 mol/l to 1 mol/l. If it is less than 0.01 mol/l, the washing effect may be insufficient; if it exceeds 1 mol/l, the sodium of the allowable value or more may remain in the silver particles 2. Further, the water used in the cleaning liquid preferably contains no impurity element which is harmful to the silver particles 2, and particularly preferably pure water.
更,進行將有機被膜層3形成於銀粒子2之表面之表面處理步驟。在對於銀粒子2之表面處理步驟,為使用界面活性劑來將銀粒子2進行,或更佳為使用界面活性劑與分散劑來進行處理。此表面處理,只要在銀粒子2乾燥前,可在任何階段進行,惟,若將氯及水溶性高分子完全除去時,銀粒子2會凝聚,由於在除去後的表面處理會難以對於銀粒子2之表面進行一樣的表面處理,故較佳為在還原同時或還原後當下來進行表面處理、或在將銀粒子2由銀粒子漿料固液分離後且為洗淨步驟前來進行表面處理、或與洗淨步驟為同時來進行表面處理。 Further, a surface treatment step of forming the organic film layer 3 on the surface of the silver particles 2 is performed. In the surface treatment step for the silver particles 2, the silver particles 2 are used for the use of a surfactant, or more preferably a surfactant and a dispersant are used for the treatment. This surface treatment can be carried out at any stage before the silver particles 2 are dried. However, when the chlorine and the water-soluble polymer are completely removed, the silver particles 2 aggregate, and it is difficult to apply silver particles to the surface after the removal. Since the surface of 2 is subjected to the same surface treatment, it is preferred to carry out surface treatment at the same time as or after reduction, or to perform surface treatment after the silver particles 2 are separated from the silver particle slurry by solid-liquid separation and before the washing step. Or surface treatment at the same time as the washing step.
在表面處理步驟,例如,藉由在將銀粒子2由銀粒子漿料固液分離後來進行表面處理,可防止由於起因為還原劑之殘留有機物等之妨礙界面活性劑或分散劑之吸附。因此,可形成充分的有機被膜層3,並可確保與溶劑或樹脂 等之相溶性及分散性。 In the surface treatment step, for example, by subjecting the silver particles 2 to solid phase separation from the silver particle slurry and then performing surface treatment, it is possible to prevent adsorption of the surfactant or the dispersant due to the residual organic matter or the like of the reducing agent. Therefore, a sufficient organic film layer 3 can be formed and can be secured with a solvent or a resin Such as compatibility and dispersibility.
又,若重複進行複數回之洗淨時,可在任一的洗淨時來進行表面處理,只要將殘留於銀粒子2的氯及剩餘的水溶性高分子除去至不會對於表面處理造成影響之程度,且以銀粒子2不會進行凝聚之狀態來進行,例如,較佳為在進行1回以上之洗淨後,再來進行表面處理。 Further, when the washing is repeated for a plurality of times, the surface treatment can be performed at any of the washings, and the chlorine remaining in the silver particles 2 and the remaining water-soluble polymer can be removed without affecting the surface treatment. To the extent that the silver particles 2 are not aggregated, for example, it is preferable to perform surface treatment after one or more washes.
例如,作為使用界面活性劑與分散劑之較佳表面處理之具體方法,進行洗淨前之表面處理時,將由銀粒子漿料固液分離所得到的銀粒子2投入於添加有界面活性劑及分散劑之水中進行攪拌,或只要投入添加有界面活性劑之水中進行攪拌後,再進而添加分散劑進行攪拌即可。又,藉由將界面活性劑及分散劑同時地添加於洗淨液,或於界面活性劑之添加後,再添加分散劑,可使洗淨與表面處理同時地進行。為了改善界面活性劑及分散劑之對於銀粒子2之吸附性,較佳為將銀粒子2投入於添加有界面活性劑之水或洗淨液進行攪拌後,再進而添加分散劑來進行攪拌者。 For example, as a specific method of preferably surface treatment using a surfactant and a dispersant, when the surface treatment before washing is performed, the silver particles 2 obtained by solid-liquid separation of the silver particle slurry are added to the surfactant and added thereto. The water of the dispersing agent may be stirred or added to the water to which the surfactant is added, and then the dispersing agent may be further added and stirred. Further, by adding the surfactant and the dispersing agent to the cleaning liquid at the same time or after adding the surfactant, the dispersing agent is added to carry out the washing and the surface treatment simultaneously. In order to improve the adsorptivity of the surfactant and the dispersant to the silver particles 2, it is preferred to introduce the silver particles 2 into the water or the washing liquid to which the surfactant is added, and then add the dispersing agent to stir the mixture. .
尚,洗淨及表面處理時所使用的裝置,只要是通常洗淨或表面處理時所使用的裝置即可,可使用例如附有攪拌機的反應槽等。 In addition, the apparatus used for washing and surface treatment may be any apparatus used for usual washing or surface treatment, and for example, a reaction tank equipped with a stirrer or the like can be used.
接著,進行將表面已形成有有機被膜層3之銀粒子2回收之回收步驟。此回收步驟為在進行表面處理及洗淨後,進行固液分離來回收銀粒子2。又,固液分離時所使用的裝置,只要是通常使用者即可,可使用例如離心機、吸 引過濾機、壓濾機等。 Next, a recovery step of recovering the silver particles 2 on which the organic film layer 3 has been formed is performed. This recovery step is carried out by subjecting the surface treatment and washing to solid-liquid separation to recover the silver particles 2. Moreover, as long as it is a normal user, the apparatus used for solid-liquid separation can be used, for example, a centrifuge, suction. Filter filter, filter press, etc.
接下來,結束洗淨及表面處理,進行使固液分離所得到的銀粒子2之水分蒸發並使乾燥的乾燥步驟。作為乾燥方法,例如,將洗淨及表面處理結束後所回收的銀粒子2放置於不銹鋼襯墊上,並使用大氣烘烤箱或真空乾燥機等市售乾燥裝置,只要以40~80℃之溫度進行加熱即可。 Next, the washing and the surface treatment are completed, and the drying step of evaporating the water of the silver particles 2 obtained by the solid-liquid separation and drying is performed. As a drying method, for example, the silver particles 2 recovered after the washing and surface treatment are placed on a stainless steel liner, and a commercially available drying device such as an air oven or a vacuum dryer is used, as long as it is 40 to 80 ° C. The temperature can be heated.
接著,將乾燥後的銀粒子2,以對於形成於表面的有機皮膜層3為不會造成損傷之程度之充分弱的能量,來充分地壓碎至作為銀糊料用為較佳之粒度,並進行分級處理之壓碎.分級步驟,而得到銀粉1。壓碎方法,只要是不會對於有機皮膜層3造成損傷之程度,未特別限定,較佳可使用噴射摩機、高速攪拌機等壓碎力為弱的裝置。壓碎力為強的裝置時,不僅會對於有機皮膜層3造成損傷,銀粉1亦有變形之情形,故不宜。分級裝置未特別限定者,可使用氣流式分級機、篩等。 Then, the dried silver particles 2 are sufficiently crushed to have a sufficiently weak energy to the extent that the organic film layer 3 formed on the surface is not damaged, and is preferably used as a silver paste. The crushing and classification steps of the classification treatment are carried out to obtain silver powder 1. The crushing method is not particularly limited as long as it does not cause damage to the organic film layer 3, and it is preferable to use a device having a weak crushing force such as a jet motor or a high-speed mixer. When the crushing force is strong, not only the organic film layer 3 is damaged, but also the silver powder 1 is deformed, so it is not suitable. The classification device is not particularly limited, and an air flow classifier, a sieve, or the like can be used.
所謂的壓碎處理,係指為將乾燥後的凝聚粉分解至表面處理前之一次粒子或二次粒子之狀態之操作。作為壓碎之手段,可使用球摩機或衝突式氣流型粉碎器、衝撃式粉碎器、筒型高速攪拌機等各種,惟,當壓碎之能量過弱時,無法充分地將在濕式處理中或乾燥過程所生成的凝聚體分解,而無法使內部摩擦角成為20°以下。另一方面,當壓碎之能量過強時,由於會對於銀粉1之表面有機皮膜層3造成損傷,或二次粒子中一次粒子彼此之結合部會被破壞,而在銀粉1之表面會新露出金屬銀之新生面,因而表 面之親水性會變大,而使在甲醇50容量%水溶液之接觸角未滿100°,或使藉由丙酮滴定法之表面SP值變得較18為大。更,露出的新生面會成為活性點,保管中會再凝聚,而亦有使內部摩擦角變得經時性增大之情形。 The term "crushing treatment" refers to an operation of decomposing the dried agglomerated powder into the state of primary particles or secondary particles before surface treatment. As a means of crushing, a ball type machine or a conflict type air flow type pulverizer, a punch type pulverizer, a barrel type high speed mixer, or the like can be used, but when the energy of crushing is too weak, it cannot be sufficiently wet-treated. The aggregate formed by the middle or drying process is decomposed, and the internal friction angle cannot be made 20 or less. On the other hand, when the energy of the crushing is too strong, the surface of the organic powder layer 3 of the silver powder 1 may be damaged, or the joint of the primary particles in the secondary particles may be destroyed, and the surface of the silver powder 1 will be new. Exposed to the new face of metal silver, thus the watch The hydrophilicity of the surface becomes large, so that the contact angle of the 50% by volume aqueous solution of methanol is less than 100°, or the surface SP value by the acetone titration method becomes larger than 18. Further, the exposed new surface becomes an active point, and re-aggregation occurs during storage, and the internal friction angle is also increased over time.
因此,不論是在使用何種壓碎處理機之情形,一邊確認內部摩擦角、接觸角、表面SP值等參數,一邊來調整壓碎條件,並抑制一次粒子彼此結合的結合部之破壞,同時必須施加以對於銀粉1表面之有機皮膜層3為不會造成損傷之程度,即未產生有機被膜層3剝離而露出銀粒子2般之壓碎處理。壓碎條件為依照壓碎裝置之大小或已製作的銀粉1之狀態等,予以適度地決定壓碎裝置之回轉數、壓碎時間、溫度等。 Therefore, it is possible to adjust the crushing conditions and suppress the breakage of the joint of the primary particles with each other while confirming the parameters such as the internal friction angle, the contact angle, and the surface SP value, regardless of the type of the crusher. It is necessary to apply a crushing treatment such that the organic film layer 3 on the surface of the silver powder 1 is not damaged, that is, the organic film layer 3 is not peeled off and the silver particles 2 are exposed. The crushing conditions are such that the number of revolutions of the crushing device, the crushing time, the temperature, and the like are appropriately determined depending on the size of the crushing device or the state of the silver powder 1 to be produced.
例如,使用高速攪拌機時,雖依照攪拌機之容量而條件會有所差異,但因應銀粒子2之投入量,以有機被膜層3為不會損傷般地,來調整攪拌機之周速與攪拌時間等。作為使用高速攪拌機時的壓碎條件,例如,將周速設定為10m/秒~40m/秒,較佳為將壓碎時間設定為10分鐘~60分鐘之程度。 For example, when a high-speed agitator is used, the conditions vary depending on the capacity of the agitator. However, the peripheral speed and the stirring time of the agitator are adjusted so that the organic coating layer 3 is not damaged in response to the amount of the silver particles 2 to be supplied. . As the crushing conditions when the high-speed mixer is used, for example, the peripheral speed is set to 10 m/sec to 40 m/sec, and it is preferable to set the crushing time to the extent of 10 minutes to 60 minutes.
尚,壓碎處理後,就除去在銀粒子漿料之生成步驟或在壓碎.分級步驟中所生成或混入的塊體狀之銀粉凝聚體為目的,較佳為進行氣流式或篩式等之分級處理。 Further, after the crushing treatment, the silver particle agglomerates formed or mixed in the step of forming the silver particles or the crushing and classifying step are removed, and it is preferred to carry out air flow or sieve type. Hierarchical processing.
在上述的銀粉1之製造方法,係將有機被膜層3形成於藉由銀粒子漿料之生成步驟所得到的銀粒子2之表面上後,藉由抑制在銀粒子2之金屬銀之新生面之再生成般地 來進行壓碎,可得到內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為100°以上的低親水性之銀粉1。更,此銀粉1,藉由丙酮滴定法之表面SP值為18以下。藉此,在此製造方法,藉由銀粉1之內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為100°以上,由於銀糊料之對於溶劑或樹脂等之潤濕性為優異,故分散性為良好,並可容易糊料化而製作銀糊料。 In the method for producing the silver powder 1 described above, the organic film layer 3 is formed on the surface of the silver particles 2 obtained by the step of forming the silver particle slurry, and then the new surface of the metal silver in the silver particles 2 is suppressed. Regenerate By crushing, a low-hydrophilic silver powder 1 having an internal friction angle of 20 or less and a contact angle of 100 or more in a methanol 50% by volume aqueous solution was obtained. Further, the silver powder 1 had a surface SP value of 18 or less by acetone titration. Therefore, in this manufacturing method, the internal friction angle of the silver powder 1 is 20° or less, and the contact angle of the 50% by volume aqueous solution of methanol is 100° or more, because of the wettability of the silver paste with respect to a solvent or a resin. It is excellent, so the dispersibility is good, and it is easy to paste and make a silver paste.
又,藉由此製造方法所製造的銀粉1,由於為進行充分的表面處理,故不僅是在製造後當下,即使是在銀糊料與樹脂或溶劑混合之際,內部摩擦角亦為20°以下,因而即使是在製造後暫時地與溶劑混合之情形,與溶劑或樹脂等之相溶性亦為良好,由於分散性優異,故可容易地糊料化。 Further, since the silver powder 1 produced by the production method is subjected to sufficient surface treatment, the internal rubbing angle is 20° even when the silver paste is mixed with the resin or the solvent, not only after the manufacture, but also when the silver paste is mixed with the resin or the solvent. In the case where it is temporarily mixed with a solvent after the production, the compatibility with a solvent or a resin is good, and since it is excellent in dispersibility, it can be easily paste-formed.
因此,由於上述銀粉1在銀糊料中為均勻地分散,故使用銀糊料來形成配線層或電極之際,可使電氣接續成為良好。 Therefore, since the silver powder 1 is uniformly dispersed in the silver paste, electrical connection can be made good by forming a wiring layer or an electrode using a silver paste.
[實施例] [Examples]
以下對於適用本發明之具體實施例進行說明。惟,本發明並不受到此等實施例任何限定。 Specific embodiments to which the present invention is applied will be described below. However, the invention is not limited by the examples.
<實施例1> <Example 1>
在實施例1,首先,在38℃之溫浴中,於保持於液溫 36℃的25%氨水36L中,一邊攪拌一邊將氯化銀2490g(住友金屬鑛山(股)製)投入,來製作銀錯合物溶液,並在溫浴中保持於36℃。 In Example 1, first, in a warm bath at 38 ° C, while maintaining the liquid temperature In 36 L of 25% ammonia water at 36 ° C, 2490 g of silver chloride (manufactured by Sumitomo Metal Mine Co., Ltd.) was charged while stirring to prepare a silver complex solution, which was kept at 36 ° C in a warm bath.
另一方面,將還原劑之抗壞血酸1318g(關東化學(股)製,試藥)溶解於36℃的純水10L中,來製作還原劑溶液。 On the other hand, 1318 g of ascorbic acid (manufactured by Kanto Chemical Co., Ltd., reagent) of the reducing agent was dissolved in 10 L of pure water at 36 ° C to prepare a reducing agent solution.
接著,將水溶性高分子之聚乙烯醇187.5g((股)Kuraray製,PVA205,相對於銀粒子為10.0質量%)分餾,並將溶解於36℃的純水4.6L之溶液混合至上述還原劑溶液中。 Next, 187.5 g of a water-soluble polymer polyvinyl alcohol (manufactured by Kuraray, PVA 205, 10.0% by mass based on the silver particles) was fractionated, and a solution of 4.6 L of pure water dissolved at 36 ° C was mixed to the above reduction. In the solution.
接著,將上述銀錯合物溶液與還原劑溶液,使用Mohno Pump(兵神裝備(股)製),分別以2.44L/min及0.90L/min送液至桶內,來將銀錯合物還原。此時的還原速度,以銀量為127g/min。尚,上述樋為使用內徑25mm及長725mm的氯乙烯製管。將含有藉由銀錯合物之還原所得的銀粒子之漿料,一邊攪拌一邊接受於接受槽中。於接受結束後,在接受槽內持續攪拌60分鐘。將攪拌結束後的上述銀粒子漿料使用壓濾機進行過濾,並將銀粒子固液分離。 Next, the silver complex solution and the reducing agent solution were supplied to the barrel at 2.44 L/min and 0.90 L/min using a Mohno Pump (manufactured by Bingshen Co., Ltd.) to separate the silver complex. reduction. The reduction rate at this time was 127 g/min in terms of the amount of silver. Further, the above-mentioned crucible is a tube made of vinyl chloride having an inner diameter of 25 mm and a length of 725 mm. The slurry containing the silver particles obtained by the reduction of the silver complex is received in the receiving tank while stirring. After the end of the acceptance, stirring was continued for 60 minutes in the receiving tank. The silver particle slurry after the completion of the stirring was filtered using a filter press, and the silver particles were solid-liquid separated.
之後,對於固液分離後的銀粒子進行表面處理。將作為表面處理劑之市售陽離子系界面活性劑之聚氧乙烯加成4級銨鹽0.90g(Croda Japan(股)製,商品名Cirrasol G-265,相對於銀粒子為0.048質量%)及分散劑之硬脂酸乳液16.87g(中京油脂(股)製,SELOSOL 920,相對 於銀粒子為0.90質量%)投入20L之純水中,並攪拌來對於銀粒子之表面進行表面處理。之後,使成為0.05mol/L之濃度般地加入NaOH,攪拌15分鐘並洗淨後,使用壓濾機進行過濾以回收銀粒子。 Thereafter, the silver particles after the solid-liquid separation are subjected to surface treatment. 0.90 g of a polyoxyethylene addition-grade ammonium salt of a commercially available cationic surfactant as a surface treatment agent (manufactured by Croda Japan Co., Ltd., trade name Cirrasol G-265, 0.048% by mass based on silver particles) and Dispersing agent stearic acid emulsion 16.87g (made by Zhongjing Oil & Fat Co., Ltd., SELOSOL 920, relative 20 L of pure water was added to the silver particles, and the surface of the silver particles was surface-treated by stirring. Thereafter, NaOH was added at a concentration of 0.05 mol/L, stirred for 15 minutes, washed, and then filtered using a filter press to recover silver particles.
接著,在將回收後的銀粒子進行乾燥前,將銀粒子投入0.05mol/L之NaOH水溶液中,攪拌15分鐘並洗淨後,使用壓濾機進行過濾並予以回收。之後,重複進行藉由此洗淨操作及過濾的固液分離操作3回。 Next, before the recovered silver particles were dried, the silver particles were placed in a 0.05 mol/L NaOH aqueous solution, stirred for 15 minutes, washed, and then filtered and collected by a filter press. Thereafter, the solid-liquid separation operation by this washing operation and filtration was repeated three times.
將固液分離後的銀粒子投入於20L之純水中,攪拌及過濾後,將銀粒子移至不銹鋼襯墊,使用真空乾燥機以60℃乾燥10小時。 The silver particles after solid-liquid separation were placed in 20 L of pure water, stirred and filtered, and then the silver particles were transferred to a stainless steel liner, and dried at 60 ° C for 10 hours using a vacuum dryer.
乾燥後為進行壓碎及分級。壓碎為秤取乾燥後的銀粒子1.5kg,並投入於5L的高速攪拌機(日本焦碳(股)製FM5C/I)中,以回轉翼為15m/秒之周速使回轉30分鐘,來進行壓碎處理。更,將壓碎後的銀粒子使用氣流式分級機(日本鑛業(股)EJ-3型),以7μm作為分級點來進行分級處理而得到銀粉。將得到的銀粉藉由SEM觀察,一次粒子之平均粒徑為0.98μm,使用雷射繞射散射法所測定的粒度(D50)為2.35μm。 After drying, it is crushed and classified. 1.5 kg of silver particles after drying were weighed and placed in a 5 L high-speed mixer (FM5C/I made by Japan Coke), and rotated for 30 minutes at a peripheral speed of 15 m/sec. Perform crushing treatment. Further, the crushed silver particles were subjected to classification treatment using a gas flow classifier (Japan Mining Co., Ltd. EJ-3 type) at a classification point of 7 μm to obtain silver powder. The obtained silver powder was observed by SEM, and the average particle diameter of the primary particles was 0.98 μm, and the particle size (D50) measured by the laser diffraction scattering method was 2.35 μm.
如以上般進行,而得到實施例1之銀粉。對於得到的銀粉進行內部摩擦角、接觸角、表面SP值之測定。 The silver powder of Example 1 was obtained as above. The internal rubbing angle, the contact angle, and the surface SP value were measured for the obtained silver powder.
內部摩擦角之測定為使用粉體層剪切力測定裝置((股)Nano Seeds公司製NS-S300型)。在常溫下將銀粉18g填充至內徑15mm的SUS製晶胞(cell)中後,將壓 入荷重之設定值設定為20N,並以壓入速度0.2mm/秒施加荷重。在達到設定荷重後,於100秒後以10μm/秒之速度開始橫剪切。尚,採樣的頻率設定為10Hz。將橫剪切開始時的壓入載重除以晶胞(cell)的斷面積之值設定為垂直應力σ(N/cm2),並將在橫剪切後所測定的剪切力之最大值除以晶胞(cell)的斷面積而得到之值設定為剪切應力τ(N/cm2)。 The internal friction angle was measured by using a powder layer shear force measuring device (NS-S300 type manufactured by Nano Seeds Co., Ltd.). After filling 18 g of silver powder into a cell of SUS having an inner diameter of 15 mm at normal temperature, the set value of the press-in load was set to 20 N, and the load was applied at a press-in speed of 0.2 mm/sec. After the set load was reached, the transverse shear was started at 100 μm/sec after 100 seconds. Still, the sampling frequency is set to 10 Hz. The value of the press-in load at the start of the transverse shear divided by the cross-sectional area of the cell is set to the vertical stress σ (N/cm 2 ), and the maximum shear force measured after the transverse shear is obtained. The value obtained by dividing the sectional area of the cell is set as the shear stress τ (N/cm 2 ).
接著,將壓入載重之設定值設定為40N,並相同地測定垂直應力σ及剪切應力τ。更,將壓入載重之設定值設定為60N,並相同地測定垂直應力σ及剪切應力τ。將在以上的3個條件中所得到的垂直應力σ作為橫軸,將剪切應力τ作為縱軸進行標繪(plot),將使用最小二乘方法所得到的近似直線之斜率(度)設定為內部摩擦角。 Next, the set value of the press-in load was set to 40 N, and the vertical stress σ and the shear stress τ were measured in the same manner. Further, the set value of the press-in load was set to 60 N, and the vertical stress σ and the shear stress τ were measured in the same manner. The vertical stress σ obtained in the above three conditions is taken as the horizontal axis, the shear stress τ is plotted as the vertical axis, and the slope (degree) of the approximate straight line obtained by the least squares method is set. For the internal friction angle.
使用以上之方法所測定的實施例1之銀粉之內部摩擦角為7.1°。將此銀粉在室溫下放置1個月後,使用與上述相同之方法來測定內部摩擦角,結果為7.8°。 The internal friction angle of the silver powder of Example 1 measured by the above method was 7.1. After the silver powder was allowed to stand at room temperature for one month, the internal friction angle was measured by the same method as above, and it was 7.8 °.
在甲醇50容量%水溶液之接觸角之測定,為使用接觸角測定裝置(協和界面科學(股)製CA-X150)。在常溫下將銀粉以約1MPa之荷重壓製成形,而得到銀粉為已壓密填充的平板狀試驗體。對於此試驗體來測定甲醇50容量%水溶液所形成的接觸角。使用此方法所測定實施例1之銀粉之接觸角為110°。 The contact angle of the methanol 50% by volume aqueous solution was measured using a contact angle measuring device (CA-X150 manufactured by Kyowa Interface Science Co., Ltd.). The silver powder was press-formed at a normal temperature at a load of about 1 MPa, and the silver powder was obtained into a flat-packed test body which was pressure-filled. The contact angle formed by the methanol 50% by volume aqueous solution was measured for this test body. The contact angle of the silver powder of Example 1 measured by this method was 110°.
藉由丙酮滴定法之表面SP值之測定,係如以下般地進行。將銀粉0.5g添加於水50ml中,一邊緩慢地攪拌一 邊將丙酮連續滴下於含有銀粉之水中,當浮游於水面的銀粒子分散,且溶液變得白濁時設定為終點。將由此時的丙酮之添加體積所計算的丙酮水溶液之表面SP值設定為銀粉之表面SP。使用此方法所測定的實施例1之銀粒子之表面SP值為16.7。 The measurement of the surface SP value by the acetone titration method was carried out as follows. 0.5 g of silver powder was added to 50 ml of water while stirring slowly. Acetone was continuously dropped in water containing silver powder, and when the silver particles floating on the water surface were dispersed and the solution became cloudy, the end point was set. The surface SP value of the aqueous acetone solution calculated from the added volume of acetone at this time was set as the surface SP of the silver powder. The surface SP value of the silver particles of Example 1 measured by this method was 16.7.
接著,使用得到的銀粉來進行糊料化之評估。糊料化之評估,首先,在不銹鋼製的小盤子中秤取銀粉9.2g,及環氧樹脂(三菱化學(股)製,JER 819)與萜品醇之重量比為1:7之媒液0.8g。此時觀察到,銀粉之表面會因為媒液而迅速地潤濕。接下來,將此使用金屬性刮勺進行混合時,為容易混合、分散為進行,可使成為糊料狀。更,將此糊料使用自公轉型混練機((股)Thinky製ARE-250型)以2000rpm混練5分鐘,並得到均勻的銀糊料。將得到的銀糊料之分散性使用研摩細度規進行評估之結果,最大粒徑Dmax為小的7μm,並展現出優異的分散性。 Next, the obtained silver powder was used for evaluation of paste formation. For the evaluation of pasteification, first, 9.2 g of silver powder was weighed in a small stainless steel plate, and a medium liquid of epoxy resin (manufactured by Mitsubishi Chemical Corporation, JER 819) and terpineol was 1:7. 0.8g. At this time, it was observed that the surface of the silver powder was quickly wetted by the vehicle liquid. Next, when mixing using a metal spatula, it is easy to mix and disperse, and it can become paste shape. Further, this paste was kneaded at 2000 rpm for 5 minutes using a self-transformation kneading machine (manufactured by Thinky ARE-250 type), and a uniform silver paste was obtained. As a result of evaluation of the dispersibility of the obtained silver paste using a mortar fine gauge, the maximum particle diameter Dmax was 7 μm small and exhibited excellent dispersibility.
<實施例2> <Example 2>
在實施例2,除了將聚乙烯醇之量設定為75g(相對於銀粒子為4.00質量%),並將高速攪拌機之回轉翼以28m/秒之周速使回轉以外,與實施例1以相同之方法得到銀粉,並同時進行評估。得到的銀粉之一次粒子之平均粒徑為1.01μm,粒度(D50)為2.73μm。 In Example 2, the same as in Example 1, except that the amount of polyvinyl alcohol was set to 75 g (4.00% by mass with respect to the silver particles), and the rotary wing of the high-speed mixer was rotated at a peripheral speed of 28 m/sec. The method of obtaining silver powder is evaluated at the same time. The primary particle of the obtained silver powder had an average particle diameter of 1.01 μm and a particle size (D50) of 2.73 μm.
實施例2的銀粉之內部摩擦角為10.4°,在室溫下放 置1個月後的內部摩擦角為10.6°。又,實施例2的銀粉之接觸角為109°,表面SP值為17.4。 The internal friction angle of the silver powder of Example 2 was 10.4°, and it was placed at room temperature. The internal friction angle after 1 month was 10.6°. Further, the contact angle of the silver powder of Example 2 was 109°, and the surface SP value was 17.4.
接著,使用得到的銀粉來進行與實施例1為相同的糊料化評估。觀察到銀粉之表面會因為媒液而迅速地潤濕。將此使用金屬性刮勺進行混合時,為容易混合、分散為進行,可使成為糊料狀。更,將此糊料與實施例1為相同地使用自公轉型混練機來進行混練,得到均勻的銀糊料。將得到的銀糊料之分散性使用研摩細度規進行評估之結果,最大粒徑Dmax為小的6μm,並展現出優異的分散性。 Next, the same paste evaluation as in Example 1 was carried out using the obtained silver powder. It was observed that the surface of the silver powder was quickly wetted by the vehicle. When this is mixed using a metal spatula, it can be easily mixed and dispersed, and it can be in the form of a paste. Further, this paste was kneaded using a self-transition kneading machine in the same manner as in Example 1 to obtain a uniform silver paste. As a result of evaluation of the dispersibility of the obtained silver paste using a mortar scale, the maximum particle diameter Dmax was 6 μm small and exhibited excellent dispersibility.
<比較例1> <Comparative Example 1>
在比較例1,除了將高速攪拌機之回轉翼以42m/秒之周速使回轉以外,與實施例1以相同之方法得到銀粉,並同時進行評估。得到的銀粉之一次粒子之平均粒徑為0.99μm,粒度(D50)為1.82μm。又,比較例1的銀粉之內部摩擦角為20.8°,相較於實施例為相當地高。又,比較例1的銀粉之接觸角為85°,表面SP值為18.7。 In Comparative Example 1, silver powder was obtained in the same manner as in Example 1 except that the rotary blade of the high-speed mixer was rotated at a peripheral speed of 42 m/sec, and evaluation was simultaneously performed. The primary particles of the obtained silver powder had an average particle diameter of 0.99 μm and a particle size (D50) of 1.82 μm. Further, the internal friction angle of the silver powder of Comparative Example 1 was 20.8°, which was considerably higher than that of the examples. Further, the contact angle of the silver powder of Comparative Example 1 was 85°, and the surface SP value was 18.7.
接著,使用得到的銀粉來進行與實施例1為相同的糊料化評估。幾乎未觀察到銀粉之表面之因為媒液的潤濕。又,將此使用金屬性刮勺進行攪拌時,為變成大的黏土狀狀態,無法使成為糊料狀。更,將此銀糊料與實施例1為相同地使用自公轉型混練機來進行混練,使成為糊料狀。將得到的銀糊料之分散性使用研摩細度規進行評估之結果,最大粒徑Dmax為大的20μm,且分散性為差。 Next, the same paste evaluation as in Example 1 was carried out using the obtained silver powder. The surface of the silver powder was hardly observed due to the wetting of the vehicle. Moreover, when this metal stirring blade is used for stirring, it is in a large clay state, and it cannot be made into a paste shape. Further, this silver paste was kneaded in the same manner as in Example 1 using a self-transition kneading machine to obtain a paste. As a result of evaluation of the dispersibility of the obtained silver paste using a mortar scale, the maximum particle diameter Dmax was 20 μm large, and the dispersibility was poor.
<比較例2> <Comparative Example 2>
在比較例2,除了將高速攪拌機之回轉翼以7m/秒之周速使回轉以外,與實施例2以相同之方法得到銀粉,並同時進行評估。得到的銀粉之一次粒子之平均粒徑為1.00μm,粒度(D50)為3.52μm。又,比較例2的銀粉之內部摩擦角為25.8°,相較於實施例為相當地高。又,比較例2的銀粉之接觸角為110°,表面SP值為17.4。 In Comparative Example 2, silver powder was obtained in the same manner as in Example 2 except that the rotary vane of the high-speed mixer was rotated at a peripheral speed of 7 m/sec, and evaluation was simultaneously performed. The primary particle of the obtained silver powder had an average particle diameter of 1.00 μm and a particle size (D50) of 3.52 μm. Further, the internal friction angle of the silver powder of Comparative Example 2 was 25.8°, which was considerably higher than that of the examples. Further, the contact angle of the silver powder of Comparative Example 2 was 110°, and the surface SP value was 17.4.
接著,使用得到的銀粉來進行與實施例1為相同的糊料化評估。幾乎未觀察到銀粉之表面之因為媒液的潤濕。又,將此使用金屬性刮勺進行攪拌時,為變成大的黏土狀狀態,無法使成為糊料狀。更,將此糊料與實施例1為相同地使用自公轉型混練機來進行混練,使成為糊料狀。將得到的銀糊料之分散性使用研摩細度規進行評估之結果,最大粒徑Dmax為大的18μm,且分散性為差。 Next, the same paste evaluation as in Example 1 was carried out using the obtained silver powder. The surface of the silver powder was hardly observed due to the wetting of the vehicle. Moreover, when this metal stirring blade is used for stirring, it is in a large clay state, and it cannot be made into a paste shape. Further, this paste was kneaded in the same manner as in Example 1 using a self-transition kneading machine to obtain a paste. As a result of evaluation of the dispersibility of the obtained silver paste using a mortar scale, the maximum particle diameter Dmax was 18 μm large, and the dispersibility was poor.
由以上的實施例及比較例可得知,即使是藉由相同方法所製作的銀粉,相較於比較例,以不使形成於銀粉表面之被膜損傷之程度而充分地壓碎的實施例1及實施例2,內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為成為100°以上,並得到與媒液之相溶性良好、分散性優異的銀粉。又,在實施例1及實施例2,進而藉由丙酮滴定法之表面SP值為18以下。更,在實施例1及實施例2,即使是將銀粉在室溫下放置1個月後,內部摩擦角亦為20°以下,抑制了凝聚之進行。 According to the above examples and comparative examples, even in the case of the silver powder produced by the same method, the first embodiment was sufficiently crushed to the extent that the film formed on the surface of the silver powder was not damaged. In the second embodiment, the internal friction angle is 20° or less, and the contact angle of the 50% by volume aqueous solution of methanol is 100° or more, and silver powder having good compatibility with the vehicle liquid and excellent dispersibility is obtained. Further, in Example 1 and Example 2, the surface SP value by the acetone titration method was 18 or less. Further, in Example 1 and Example 2, even after the silver powder was allowed to stand at room temperature for one month, the internal rubbing angle was 20 or less, and the progress of aggregation was suppressed.
另一方面,在比較例1,由於壓碎條件過強,而損傷了形成於銀粉表面之有機被膜層,內部摩擦角變得較20°為大,接觸角亦變得較100°為小。更,表面SP值亦變得較18為大。又,在比較例2,由於壓碎條件弱,無法充分地將凝聚體分解,因而內部摩擦角為25.8°,變得相當地大。藉由,在比較例1及比較例2,與媒液之相溶性為差,且銀粉之分散性變差。 On the other hand, in Comparative Example 1, since the crushing conditions were too strong and the organic film layer formed on the surface of the silver powder was damaged, the internal rubbing angle was larger than 20°, and the contact angle was also smaller than 100°. Furthermore, the surface SP value also becomes larger than 18 . Further, in Comparative Example 2, since the crushing conditions were weak, the aggregates could not be sufficiently decomposed, and the internal friction angle was 25.8°, which was considerably large. In Comparative Example 1 and Comparative Example 2, the compatibility with the vehicle liquid was poor, and the dispersibility of the silver powder was deteriorated.
1‧‧‧銀粉 1‧‧‧Silver powder
2‧‧‧銀粒子 2‧‧‧Silver particles
3‧‧‧有機被膜層 3‧‧‧Organic coating
[圖1]模擬展示有關銀粒子形態與粒子之表面狀態之圖。 [Fig. 1] A simulation showing a graph of the morphology of silver particles and the surface state of particles.

Claims (5)

  1. 一種銀粉,其特徵係內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為100°以上。 A silver powder characterized by an internal friction angle of 20 or less and a contact angle of 100 or more in a 50% by volume aqueous solution of methanol.
  2. 如申請專利範圍第1項之銀粉,其中,進而藉由丙酮滴定法之表面SP值為18以下。 The silver powder of the first aspect of the patent application, wherein the surface SP value by the acetone titration method is 18 or less.
  3. 如申請專利範圍第1或2項之銀粉,其中,在與銀糊料之溶劑混合之際的上述內部摩擦角為20°以下。 The silver powder according to claim 1 or 2, wherein the internal friction angle is 20 or less when mixed with a solvent of the silver paste.
  4. 一種銀粉之製造方法,其特徵係藉由對於使用濕式還原法所合成的銀粒子進行表面處理,在表面形成有機皮膜層後,以不對於上述有機被膜層造成損傷之程度充分地進行壓碎處理,來製造內部摩擦角為20°以下,且在甲醇50容量%水溶液之接觸角為100°以上之銀粉。 A method for producing a silver powder characterized by subjecting a silver particle synthesized by a wet reduction method to surface treatment, and forming an organic film layer on a surface thereof, and then sufficiently crushing the organic film layer without causing damage to the organic film layer The silver powder having an internal friction angle of 20 or less and a contact angle of 100 or more in a methanol 50% by volume aqueous solution was produced.
  5. 如申請專利範圍第4項之銀粉之製造方法,其中,上述壓碎處理之方法為使用高速攪拌機,且攪拌翼之周速為10m/秒以上、40m/秒以下之條件。 The method for producing a silver powder according to the fourth aspect of the invention, wherein the method of crushing is a high-speed agitator, and the peripheral speed of the stirring blade is 10 m/sec or more and 40 m/sec or less.
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