JP3865204B2 - Ceramic green sheet composition - Google Patents

Description

ただし化１において、ｎ＝１〜６である。
【００１０】
ポリαオレフィンのセラミック粉末１００重量部に対する添加量は好ましくは０．３〜４重量部である。また、バインダーに対するポリαオレフィンの添加量は、好ましくは４．６〜６１．５ＰＨＲである。ポリαオレフィンのセラミック粉末に対する添加量が０．３重量部未満か、あるいはバインダーに対するポリαオレフィンの添加量が４．６ＰＨＲ未満であると、ポリαオレフィンの添加による剥離強度の低下の効果がほとんど得られない。
【００１１】
一方、ポリαオレフィンのセラミック粉末に対する添加量が４重量部を超えるか、あるいはバインダーに対するポリαオレフィンの添加量が６１．５ＰＨＲを超えると、ショート不良率が高くなり、歩留が悪くなる。
【００１２】
請求項２のセラミックグリーンシート用組成物は、セラミック粉末と、バインダーと、可塑剤とを含むセラミックグリーンシート用組成物であって、
前記組成物中にさらに剥離剤としてポリブテンを含有することを特徴とする。
【００１３】
請求項２のグリーンシート組成物は、請求項１と同様の工程により、グリーンシートを構成するものとして得られる。ポリブテンは、下記の化２の化学式で示される。
【００１４】
【化２】

ただし化２において、ｎ＝４〜２６である。
【００１５】
ポリブテンのセラミック粉末１００重量部に対する添加量は好ましくは０．３〜４重量部である。また、バインダーに対するポリブテンの添加量は、好ましくは４．６〜６１．５ＰＨＲである。ポリブテンのセラミック粉末に対する添加量が０．３重量部未満か、あるいはバインダーに対するポリブテンの添加量が４．６ＰＨＲ未満であると、ポリブテンの添加による剥離強度の低下の効果が得られない。
【００１６】
一方、ポリブテンのセラミック粉末に対する添加量が４重量部を超えるか、あるいはバインダーに対するポリブテンの添加量が６１．５ＰＨＲを超えると、ショート不良率が高くなり、歩留が悪くなる。
【００１７】
【発明の実施の形態】
本発明のセラミックグリーンシートは、セラミック粉末をバインダー、可塑剤、溶媒、剥離剤であるポリαオレフィンまたはポリブテンと共に混合してスラリーとし、このスラリーを、例えば特開平８−１３０１５２号あるいは特開平９−９２５６６号において開示したように、リールに巻かれたＰＥＴフィルム等の可撓性支持体を引き出し、張力を加えた状態で縦に張り、これを一定速度で移動しながら、押し出し式塗布ヘッドを前記可撓性支持体に押しつけ、スラリーを入れた容器に圧力をかけて前記押し出し式塗布ヘッドより前記可撓性支持体の面に押し出して薄層として塗布する。その後、例えば約７０℃乾燥して前記溶媒を飛ばしてセラミックグリーンシートを作製する。その後、グリーンシートに電子部品の多数個分の電極を厚膜印刷する。そして該グリーンシートを１セット分ごとに切断した後、前記可撓性支持体からグリーンシートを剥離する。そして剥離したグリーンシートを積層し、圧着して成形する。
【００１８】
その後個々のチップに切断し、例えば約３００℃で所定時間加熱することにより、前記バインダー、可塑剤、剥離剤を飛ばし、Ｎｉ系電極の場合には約１２５０℃で焼成する。そして焼付け等により端子電極を設ける。なお、端子電極を、積層工程ですでに積層体の両端面等に導体膜として形成する場合には、焼成後にめっきを施すことにより完成させることができる。
【００１９】
本発明においては、グリーンシート組成物中に、剥離剤としてポリαオレフィンまたはポリブテンを含有させることにより、剥離を容易化する。
【００２０】
（実施例１）
積層コンデンサを作製するため、平均粒径０．５μｍのチタン酸バリウム粉末１００重量部に、バインダーとしてのポリメタクリル酸イソブチル６．５重量部、溶媒としてのメチルエチルケトン４０重量部およびトルエン３０重量部、可塑剤としてのブチルベンジルフタレート３．５重量部とを加えると共に、剥離剤として、ポリαオレフィン（出光石油化学社製ＰＡＯ５００４）の量を種々に変更して加え、メディアと共にボールミル分散機で混合、分散しスラリーとした。
【００２１】
その後、前述した押し出し式塗布ヘッドにより、可撓性支持体としてのＰＥＴフィルムにスラリーを塗布し、乾燥することにより、５μｍの厚みで２０ｃｍ幅のフィルム付きグリーンシートを得た。次にコンデンサ電極となるＮｉペーストをスクリーン印刷によりグリーンシート表面に形成した。その後、このグリーンシートを１セット分ずつ切断した。１セット分の長さは２０ｃｍであり、コンデンサの約５０００個分である。
【００２２】
このようにコンデンサ電極を形成したグリーンシートの剥離強さを調べるため、ＰＥＴフィルムのグリーンシート形成面の反対側の面を固定し、グリーンシートをＰＥＴフィルムに対して９０度の角度で剥離する際に要する力を市販の引張り強度試験機により測定した。
【００２３】
また、このように作製したグリーンシートを２００枚重ね、加圧成形した。その後個々のチップに切断し、３００℃で加熱して前記バインダー、可塑剤、剥離剤を飛ばし、その後、１２５０℃で焼成した。その後、銅ペーストの塗布、焼成、めっきにより端子電極を形成した。そして作製したコンデンサについてショート不良率を調べた。その結果を表１に示す。
【００２４】
【表１】

【００２５】
表１に示すように、剥離剤を添加しない場合、あるいは添加量がセラミック粉末１００重量部に対して０．３重量部に達しない場合には、剥離に要する力（剥離強さ）は４５ｍｍＮ以上となり、剥離が困難となり、良好な積層成形体を得ることができない。
【００２６】
一方、剥離剤の添加量がセラミック粉末１００重量部に対して０．３重量部以上になると、剥離強さは４５Ｎ以下になり、剥離性が向上し、グリーンシートは破断することなく剥離可能となる。ただし、剥離剤の添加量がセラミック粉末１００重量部に対して４重量部を超えると、ショート不良率が増大する。また、４重量部を超えると、積層時の圧着における層間の密着が悪くなり、焼成において、デラミネーションやクラックが発生し、耐圧不良率が急激に増加するので、剥離剤の添加量は、０．３〜４重量部の範囲にすることが好ましい。この範囲は、バインダーに対する重量比×１００の値であるＰＨＲで表示すると、
３／６．５）×１００＝４．６ＰＨＲ
ないし（４／６．５）×１００＝６１．５ＰＨＲの範囲に相当する。なお、前記剥離剤の添加量の範囲はさらに好ましくは１〜３重量部／セラミック粉末１００部（１５．４〜４６．２ＰＨＲ）である。
【００２７】
（実施例２）
前記剥離剤として前記ポリαオレフィンの代わりにポリブテン（出光石油化学社製出光ポリブデンＯＨ）を用い、その添加量を種々に変えて前記同様にシート剥離性、、剥離強さ、ショート不良率を調べた結果を表２に示す。
【００２８】
表２から分かるように、ポリブテンの場合にもポリαオレフィンの場合と同様の剥離性向上の効果が得られる。ポリブテンの場合にも、剥離剤のセラミック粉末に対する添加量は、０．３〜４重量部（４．６〜６１．５ＰＨＲ）の範囲にすることが好ましく、さらに好ましくは、１〜３重量部／セラミック粉末１００部（１５．４〜４６．２ＰＨＲ）である。
【００２９】
本発明は、積層コンデンサのみならず、積層インダクタあるいはこれらの複合電子部品にも適用できる。
【００３０】
【表２】

【００３１】
【発明の効果】
本発明によれば、グリーンシートにポリαオレフィンまたはポリブテンを添加したので、グリーンシートを薄くした場合にも剥離性が向上し、セラミック積層電子部品、特にコンデンサを得る場合に、誘電体層を薄くすることができるので、高い容量のコンデンサを容易に得ることができ、グリーンシートを使用する積層電子部品の小型化、薄型化を可能とする。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composition for a ceramic green sheet for producing a multilayer electronic component such as a multilayer ceramic capacitor, an inductor or a composite thereof.
[0002]
[Prior art]
When manufacturing laminated electronic components using green sheets, ceramic powder, binders made of resins such as polymethacrylic acid esters and poly vinyl brillials, plasticizers such as phthalic acid esters, ketones, aromatic hydrocarbons, alcohols, etc. The solvent is mixed to make a slurry. And this slurry is apply | coated to flexible supports, such as a polyethylene terephthalate (PET) film by which release agents, such as silicone, were apply | coated to the surface. Then, it is dried and the solvent is removed by evaporation to produce a ceramic green sheet. Thereafter, electrodes for a large number of electronic components are printed on the green sheet. Then, the green sheet is cut for each set in which electrodes for several thousand chips are formed, and then the green sheet is peeled from the flexible support. Then, the peeled green sheets are stacked and pressed to form.
[0003]
[Problems to be solved by the invention]
As a method for increasing the capacity of a multilayer ceramic capacitor, a reduction in the thickness of a dielectric layer has been studied. In order to make the dielectric layer thinner, it is necessary to make the ceramic green sheet thinner. However, the thinned ceramic green sheet has a low mechanical strength, and if the peel strength is the same as the conventional one, the sheet is likely to break when peeled from the flexible support. It becomes difficult.
[0004]
In order to solve the problem of breakage at the time of peeling when the green sheet is thinned, it is conceivable to increase the mechanical strength by increasing the ratio of a resin such as a binder in the green sheet. However, when the amount of resin in the green sheet is increased, structural defects such as delamination (delamination between the dielectric layer and the conductor layer) are likely to occur during firing.
[0005]
On the other hand, instead of changing the composition of the green sheet, if the release agent applied to the film as the flexible support is made easy to peel off the green sheet, the slurry is repelled when the slurry is applied to the film. Defects such as pinholes are likely to occur. In addition, wrinkles are easier with the green sheet on the film.
[0006]
In the present invention, in view of the above-mentioned problems of the prior art, in order to reduce the thickness and performance of laminated electronic components, when the ceramic green sheet is thinned, the peeling of the green sheet from the flexible support is not broken. An object of the present invention is to provide a composition for a ceramic green sheet that can be easily performed.
[0007]
[Means for Solving the Problems]
The ceramic green sheet composition of claim 1 is a ceramic green sheet composition comprising ceramic powder, a binder, and a plasticizer,
The composition further comprises a polyalphaolefin as a release agent.
[0008]
The green sheet composition of claim 1 is obtained as a green sheet by mixing with ceramic powder, a binder, a plasticizer, and a solvent to form a slurry, and then removing the solvent by drying. The polyalphaolefin is represented by the following chemical formula 1.
[0009]
[Chemical 1]

However, in Chemical formula 1, n = 1 to 6.
[0010]
The amount of polyαolefin added to 100 parts by weight of the ceramic powder is preferably 0.3 to 4 parts by weight. Moreover, the addition amount of the polyalphaolefin with respect to a binder becomes like this. Preferably it is 4.6-61.5PHR. If the addition amount of the poly α olefin to the ceramic powder is less than 0.3 parts by weight, or the addition amount of the poly α olefin to the binder is less than 4.6 PHR, the effect of lowering the peel strength due to the addition of the poly α olefin is little. I can't get it.
[0011]
On the other hand, when the addition amount of the poly α olefin to the ceramic powder exceeds 4 parts by weight or the addition amount of the poly α olefin to the binder exceeds 61.5 PHR, the short-circuit defect rate increases and the yield deteriorates.
[0012]
The ceramic green sheet composition of claim 2 is a ceramic green sheet composition comprising ceramic powder, a binder, and a plasticizer,
The composition further comprises polybutene as a release agent.
[0013]
The green sheet composition of claim 2 is obtained as a constituent of the green sheet by the same process as in claim 1. Polybutene is represented by the following chemical formula.
[0014]
[Chemical 2]

However, in Chemical formula 2, n = 4 to 26.
[0015]
The amount of polybutene added to 100 parts by weight of the ceramic powder is preferably 0.3 to 4 parts by weight. The amount of polybutene added to the binder is preferably 4.6 to 61.5 PHR. If the amount of polybutene added to the ceramic powder is less than 0.3 parts by weight or the amount of polybutene added to the binder is less than 4.6 PHR, the effect of reducing the peel strength due to the addition of polybutene cannot be obtained.
[0016]
On the other hand, if the amount of polybutene added to the ceramic powder exceeds 4 parts by weight, or the amount of polybutene added to the binder exceeds 61.5 PHR, the short-circuit defect rate increases and the yield deteriorates.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
In the ceramic green sheet of the present invention, ceramic powder is mixed with a binder, a plasticizer, a solvent, a polyalphaolefin or polybutene as a release agent to form a slurry, and this slurry is, for example, disclosed in JP-A-8-130152 or JP-A-9-9- As disclosed in US Pat. No. 92,566, a flexible support such as a PET film wound on a reel is pulled out, stretched vertically with tension applied, and moved at a constant speed, while the extrusion-type coating head is A pressure is applied to the flexible support, pressure is applied to the container in which the slurry is placed, and the film is extruded from the extrusion-type application head onto the surface of the flexible support and applied as a thin layer. Then, for example, the ceramic green sheet is produced by drying at about 70 ° C. and removing the solvent. Thereafter, electrodes for a large number of electronic components are printed on the green sheet by thick film printing. And after cutting this green sheet for every set, a green sheet is peeled from the said flexible support body. Then, the peeled green sheets are stacked and pressed to form.
[0018]
After that, it is cut into individual chips, and heated at a temperature of about 300 ° C. for a predetermined time, thereby skipping the binder, plasticizer, and release agent. In the case of a Ni-based electrode, it is fired at about 1250 ° C. Then, terminal electrodes are provided by baking or the like. In addition, when forming a terminal electrode as a conductor film in the both end surfaces of a laminated body already by a lamination process, it can complete by giving plating after baking.
[0019]
In the present invention, peeling is facilitated by incorporating a polyalphaolefin or polybutene as a release agent in the green sheet composition.
[0020]
Example 1
In order to produce a multilayer capacitor, 100 parts by weight of barium titanate powder having an average particle size of 0.5 μm, 6.5 parts by weight of polybutyl methacrylate as a binder, 40 parts by weight of methyl ethyl ketone as a solvent and 30 parts by weight of toluene, plastic Add 3.5 parts by weight of butyl benzyl phthalate as an agent, add various amounts of poly alpha olefin (PAO5004 manufactured by Idemitsu Petrochemical Co., Ltd.) as a release agent, and mix and disperse with media in a ball mill disperser A slurry was obtained.
[0021]
Then, the slurry was apply | coated to PET film as a flexible support body with the extrusion-type application | coating head mentioned above, and it dried and obtained the green sheet with a film of 20 cm width by thickness of 5 micrometers. Next, Ni paste used as a capacitor electrode was formed on the green sheet surface by screen printing. Thereafter, the green sheets were cut one set at a time. The length of one set is 20 cm, which is about 5000 capacitors.
[0022]
In order to examine the peel strength of the green sheet on which the capacitor electrode is formed in this way, when the surface opposite to the green sheet forming surface of the PET film is fixed and the green sheet is peeled at an angle of 90 degrees with respect to the PET film The force required for this was measured with a commercially available tensile strength tester.
[0023]
In addition, 200 green sheets thus produced were stacked and pressure-formed. Thereafter, the chips were cut into individual chips, heated at 300 ° C. to remove the binder, plasticizer, and release agent, and then fired at 1250 ° C. Thereafter, terminal electrodes were formed by applying copper paste, firing, and plating. And the short-circuit defective rate was investigated about the produced capacitor. The results are shown in Table 1.
[0024]
[Table 1]

[0025]
As shown in Table 1, when no release agent is added, or when the addition amount does not reach 0.3 parts by weight with respect to 100 parts by weight of the ceramic powder, the force (peel strength) required for peeling is 45 mmN or more. Therefore, it becomes difficult to peel off, and a good laminated molded body cannot be obtained.
[0026]
On the other hand, when the addition amount of the release agent is 0.3 parts by weight or more with respect to 100 parts by weight of the ceramic powder, the peel strength is 45 N or less, the peelability is improved, and the green sheet can be peeled without breaking. Become. However, when the addition amount of the release agent exceeds 4 parts by weight with respect to 100 parts by weight of the ceramic powder, the short-circuit defect rate increases. On the other hand, if the amount exceeds 4 parts by weight, the adhesion between the layers in the pressure bonding at the time of lamination deteriorates, delamination and cracks occur during firing, and the withstand voltage failure rate increases rapidly. It is preferable to be in the range of 3 to 4 parts by weight. This range is expressed by PHR which is a value of weight ratio to binder × 100.
3 / 6.5) × 100 = 4.6 PHR
To (4 / 6.5) × 100 = 61.5 PHR. In addition, the range of the addition amount of the release agent is more preferably 1 to 3 parts by weight / 100 parts of ceramic powder (15.4 to 46.2 PHR).
[0027]
(Example 2)
Using polybutene (Idemitsu Petrochemical Co., Ltd., Idemitsu Polybuden OH) instead of the poly-α-olefin as the release agent, the amount of addition was changed in various ways, and the sheet peelability, peel strength, and short-circuit defect rate were similarly examined. The results are shown in Table 2.
[0028]
As can be seen from Table 2, in the case of polybutene, the same effect of improving peelability as in the case of polyα-olefin can be obtained. Also in the case of polybutene, the amount of release agent added to the ceramic powder is preferably in the range of 0.3 to 4 parts by weight (4.6 to 61.5 PHR), more preferably 1 to 3 parts by weight / 100 parts of ceramic powder (15.4-46.2 PHR).
[0029]
The present invention can be applied not only to a multilayer capacitor but also to a multilayer inductor or a composite electronic component thereof.
[0030]
[Table 2]

[0031]
【The invention's effect】
According to the present invention, since poly alpha olefin or polybutene is added to the green sheet, the peelability is improved even when the green sheet is thinned, and the dielectric layer is thinned when obtaining a ceramic multilayer electronic component, particularly a capacitor. Therefore, a capacitor having a high capacity can be easily obtained, and the multilayer electronic component using the green sheet can be reduced in size and thickness.

Claims (2)

A ceramic green sheet composition comprising a ceramic powder, a binder, and a plasticizer and coated on a flexible support ,
The chemical formula of the following chemical formula 1 as a release agent in the composition (wherein n = 1 to 6 in chemical formula 1).

The composition for ceramic green sheets characterized by containing the poly-alpha olefin displayed by these. A ceramic green sheet composition comprising a ceramic powder, a binder, and a plasticizer and coated on a flexible support ,
The chemical formula of the following chemical formula 2 as a release agent in the composition (wherein n = 4 to 26 in chemical formula 2).

The composition for ceramic green sheets characterized by containing the polybutene displayed by these.