JP4275820B2 - Method for producing polyvinyl acetal resin - Google Patents
Method for producing polyvinyl acetal resin Download PDFInfo
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- JP4275820B2 JP4275820B2 JP26603099A JP26603099A JP4275820B2 JP 4275820 B2 JP4275820 B2 JP 4275820B2 JP 26603099 A JP26603099 A JP 26603099A JP 26603099 A JP26603099 A JP 26603099A JP 4275820 B2 JP4275820 B2 JP 4275820B2
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- polyvinyl acetal
- acetal resin
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Description
【０００１】
【発明の属する技術分野】
本発明はポリビニルアセタール樹脂の製造方法に関する。
【０００２】
【従来の技術】
ポリビニルブチラール樹脂に代表されるポリビニルアセタール樹脂は、その優れた接着性によって、塗料、接着剤、安全ガラス用中間膜等の広範な分野で汎用されている。
これらのポリビニルアセタール樹脂は、ポリビニルアルコールとアルデヒド類とを縮合反応させて得られるが、その製造方法としては、ポリビニルアルコールを有機溶媒に分散させ、酸触媒を用い、アルデヒド化合物を加えて反応させ、生成したポリビニルアセタール樹脂溶液からポリビニルアセタール樹脂を析出させた後、水洗乾燥させる溶解法や酸触媒の存在下に水相中で反応が進行し、生成したポリビニルアセタール樹脂が溶解性を失って生成系に粒子状に沈殿して反応系の水溶媒から分離する沈殿法等が知られている。上記沈殿法は、単一工程で水溶液から粉末状のポリビニルアセタール樹脂を得ることができるので、生成系のポリビニルアセタール樹脂の有機溶剤溶液からポリビニルアセタール樹脂を析出させる工程を余分に必要とする溶解法に比して工程が少なく且つ容易であり、より高い生産性を示す方法として評価される。
【０００３】
しかし、沈殿法は、反応温度が高くなって生成系のポリビニルアセタール樹脂の粒子が粗大化し易く、その結果、粗大化したポリビニルアセタール樹脂の粒子内に、使用した酸触媒が多量に取り込まれることとなる。
【０００４】
上記酸触媒等の残渣の夾雑は、ポリビニルアセタール樹脂をセラミックス系電子部品のバインダー等の用途に供される場合、特に、その品質が問題とされるものであって、上記ポリビニルアセタール樹脂の品質低下を避けるため、前記する縮合反応を比較的低温度で実施し、生成系のポリビニルアセタール樹脂を微粒子化している。
【０００５】
しかし、如何に生成系のポリビニルアセタール樹脂を微粒子化しても、得られたスラリー状生成物から水洗のみで上記酸触媒等の夾雑を含まないポリビニルアセタール樹脂を分離することは難しく、通常、水洗工程に中和工程が組み込まれる。
即ち、前記する縮合反応で得られたスラリー状生成物の母液中の酸触媒を中和剤を投入する常温中和、又は、水洗して酸触媒濃度を減じた後、上記中和剤を投入し、中和塩及び残存中和剤を水洗し、乾燥して微粒子状ポリビニルアセタール樹脂を製品化している。
【０００６】
然るに、上記酸触媒の中和反応は、反応熱によって得られた微粒子状ポリビニルアセタール樹脂が、そのガラス転移温度（以下、Ｔｇと略称する）以上の中和恒温域の温度になって粒子同士の合着が発生し、合着粒子内に中和塩及び残存中和剤が一部取り込まれてしまい、次いで行われる水洗処理では、これらの合着粒子内に取り込まれた中和塩等を完全には洗浄除去することが難しくなる。
上記中和反応の中和恒温域の温度を低下させようと中和剤投入量を加減すると酸触媒が残存し、別にポリビニルアセタール樹脂の品質問題を惹起することになる。
【０００７】
【発明が解決しようとする課題】
本発明は、上記事実に鑑みなされたものであって、その目的とするところは、前記する縮合反応で生成したポリビニルアセタール樹脂スラリー中の酸触媒を中和する過程で生成する中和塩等の、ポリビニルアセタール樹脂粒子内への取り込みを抑制し、夾雑電解質の含有量の少ない優れたポリビニルアセタール樹脂を製造する方法を提供することにある。
【０００８】
【課題を解決するための手段】
請求項１記載の発明のポリビニルアセタール樹脂の製造方法は、酸触媒の存在下に水相中でポリビニルアルコールとアルデヒド類とを縮合反応させて得られたポリビニルアセタール樹脂生成物を中和、水洗するポリビニルアセタール樹脂の製造方法であって、上記中和、水洗工程は、複数回繰り返して行われ、初回の中和反応は、得られたポリビニルアセタール樹脂生成物が、該樹脂生成物のガラス転移温度に達すると同時に実施されるものである。
【０００９】
請求項２記載の発明のポリビニルアセタール樹脂の製造方法は、請求項１記載の発明のポリビニルアセタール樹脂の製造方法であって、初回の中和水洗後に行われる中和反応が、得られたポリビニルアセタール樹脂のガラス転移温度以上の温度に達した後に実施されるものである。
【００１０】
本発明のポリビニルアセタール樹脂の製造方法で用いられるポリビニルアルコール及びアルデヒド類は、酸触媒の存在下に水相中で縮合反応によりアセタール化し、これらよりポリビニルアセタール樹脂が得られるものであれば特に限定されるものではない。
上記酸触媒は、上記アセタール化反応を良好に触媒するものであれば特に限定されるものではない。
【００１１】
本発明のポリビニルアセタール樹脂の製造方法にあって、複数回繰り返して行われる上記中和、水洗工程は、中和処理が施され、水洗処理される工程が少なくとも２回以上行われることを指すものであるが、先ず水洗して酸触媒濃度を減じた後、上記中和剤を投入し、更に水洗処理するように、１回の中和処理に対して、水洗処理が複数回にわたる場合でも、中和処理の内容から、上記中和、水洗工程は１回とカウントされるものである。
【００１２】
請求項１記載の発明のポリビニルアセタール樹脂の製造方法は、酸触媒の存在下に水相中でポリビニルアルコールとアルデヒド類とを縮合反応させて得られたポリビニルアセタール樹脂生成物を中和、水洗するポリビニルアセタール樹脂の製造方法であって、上記中和、水洗工程は、複数回繰り返して行われ、初回の中和反応は、得られたポリビニルアセタール樹脂生成物が、該樹脂生成物のＴｇに達すると同時に実施されるものであるので、ポリビニルアセタール樹脂の粒子同士の合着が阻止され、もしくは合着が発生する前に、生成した中和塩及び残存中和剤が洗い流サレル。よって、ポリビニルアセタール樹脂の粒子に付着し、もしくは該粒子内に取り込まれた中和塩及び残存中和剤は極めて微量となり、繰り返し行われる中和、水洗工程によって、中和塩及び残存中和剤等の夾雑量は、より低レベルとなって、半導体素子等の電子部品等に供されるセラミックス類のバインダー等として高い性能を発揮し得るものとなるのである。
【００１３】
請求項２記載の発明のポリビニルアセタール樹脂の製造方法は、請求項１記載の発明のポリビニルアセタール樹脂の製造方法であって、初回の中和水洗後に行われる中和反応が、得られたポリビニルアセタール樹脂のＴｇ以上の温度に達した後に実施されるものであるので、初回の中和水洗によって殆ど除去され、僅かに残存する酸触媒も、中和恒温時のポリビニルアセタール樹脂のＴｇ以上の温度において新たな中和剤によって中和処理されるので、殆ど完全に中和され、水洗によってポリビニルアセタール樹脂より除去される。
【００１４】
上記中和処理においてポリビニルアセタール樹脂は、そのＴｇ以上の中和恒温域の温度に曝されるので、該樹脂粒子同士の合着の発生はあるが、既に繰り返し行われた中和、水洗工程の後であるので、合着粒子内に一部取り込まれている中和塩等の夾雑物も極微量となっており、水洗、乾燥後のポリビニルアセタール樹脂粒子中の、残存中和塩及び残存中和剤量は極微量となっているのである。
【００１５】
【発明の実施の形態】
以下、本発明の実施例を説明するが、本発明は、これらの実施例のみに限定されるものではない。
【００１６】
（実施例１）
常法により、鹸化度９７．５％、重合度３６０のポリビニルアルコール２８３ｇを純水２６５７ｇに加え、攪拌して溶解させた。得られたポリビニルアルコール水溶液に濃度３５重量％の塩酸３６４ｇとｎ−ブチルアルデヒド１９６ｇを加えてアセタール化反応を行い、白色微粒子からなるポリビニルアセタール樹脂スラリーを得た。得られたポリビニルアセタール樹脂微粒子の見掛け粒子径は１０〜２０μｍ、アセタール化度は７４モル％、Ｔｇは６１℃であった。
【００１７】
得られたポリビニルアセタール樹脂スラリー母液中の塩素含有量が１０ｐｐｍになるまで水洗して酸触媒濃度を減じた後、ポリビニルアセタール樹脂スラリー４０００重量部を、該ポリビニルアセタール樹脂スラリー濃度が１０重量％になるように調整し、ソーダ灰４重量部を添加し、攪拌しながら中和処理系の温度が６１℃となるまで加熱した。
上記中和処理系の温度が６１℃に達したとき、直ちに水洗処理を行い生成した中和塩と残存中和剤等を除去した。
第１次の中和、水洗後のポリビニルアセタール樹脂スラリー母液中の塩素含有量が１０ｐｐｍ、ナトリウム含有量が６ｐｐｍであった。
【００１８】
次いで、第１次の中和、水洗処理が行われたポリビニルアセタール樹脂スラリー４０００重量部を、該ポリビニルアセタール樹脂スラリー濃度が１０重量％になるように調整し、ソーダ灰０．５重量部を添加し、攪拌しながら中和処理系の温度が６５℃となるまで加熱し、中和恒温を３時間とった後、水洗処理を行い生成した中和塩と残存中和剤等を除去した。
第２次の中和、水洗後のポリビニルアセタール樹脂スラリー母液中の塩素含有量が１０ｐｐｍ、ナトリウム含有量が８ｐｐｍであった。
第２次の中和、水洗処理されたポリビニルアセタール樹脂スラリーを乾燥し、白色微粒子状のポリビニルアセタール樹脂を作製した。
得られたポリビニルアセタール樹脂の見掛け粒子径は８０〜１００μｍ、塩素含有量が５９ｐｐｍ、ナトリウム含有量が４６ｐｐｍであった。
【００１９】
（比較例１）
実施例１の第１次の中和、水洗処理の中和処理系の温度を、６１℃から６５℃に変更し、中和恒温を３時間とった後、水洗処理を行ったこと以外は、実施例１と同様に、中和、水洗処理を行い、１回の中和、水洗処理後、乾燥工程を経て、白色微粒子状のポリビニルアセタール樹脂を作製した。
中和、水洗処理後のポリビニルアセタール樹脂スラリー母液中の塩素含有量が８ｐｐｍ、ナトリウム含有量が７ｐｐｍであった。又、得られたポリビニルアセタール樹脂の見掛け粒子径は８０〜１００μｍ、塩素含有量が３２０ｐｐｍ、ナトリウム含有量が３００ｐｐｍであった。
【００２０】
（実施例２）
常法により、鹸化度９４．８％、重合度８２０のポリビニルアルコール３２２ｇを純水２５９７ｇに加え、攪拌して溶解させた。得られたポリビニルアルコール水溶液に濃度３５重量％の塩酸３６４ｇとｎ−ブチルアルデヒド２１７ｇを加えてアセタール化反応を行い、白色微粒子からなるポリビニルアセタール樹脂スラリーを得た。得られたポリビニルアセタール樹脂微粒子の見掛け粒子径は１０〜２０μｍ、アセタール化度は７４モル％、Ｔｇは６０℃であった。
【００２１】
以降の工程は、第１次の中和、水洗工程における中和時の加熱温度を６０℃に変更したこと以外は、実施例１と同様にして第２次の中和、水洗工程並びに乾燥工程を経て白色微粒子状のポリビニルアセタール樹脂を作製した。
第１次の中和、水洗後のポリビニルアセタール樹脂スラリー母液中の塩素含有量が８ｐｐｍ、ナトリウム含有量が６ｐｐｍであり、第２次の中和、水洗後のポリビニルアセタール樹脂スラリー母液中の塩素含有量が９ｐｐｍ、ナトリウム含有量が８ｐｐｍであった。
又、得られたポリビニルアセタール樹脂の見掛け粒子径は８０〜１００μｍ、塩素含有量が１２０ｐｐｍ、ナトリウム含有量が９６ｐｐｍであった。
【００２２】
（比較例２）
実施例２の第１次の中和、水洗処理の中和処理系の温度を、６０℃から６５℃に変更し、中和恒温を３時間とった後、水洗処理を行ったこと以外は、実施例１と同様に、中和、水洗処理を行い、１回の中和、水洗処理後、乾燥工程を経て、白色微粒子状のポリビニルアセタール樹脂を作製した。
中和、水洗処理後のポリビニルアセタール樹脂スラリー母液中の塩素含有量が１０ｐｐｍ、ナトリウム含有量が８ｐｐｍであった。又、得られたポリビニルアセタール樹脂の見掛け粒子径は８０〜１００μｍ、塩素含有量が４２０ｐｐｍ、ナトリウム含有量が３９０ｐｐｍであった。
【００２３】
【発明の効果】
請求項１記載の発明のポリビニルアセタール樹脂の製造方法は、上述のように構成されているので、酸触媒の存在下に水相中でポリビニルアルコールとアルデヒド類を縮合反応させて得られたポリビニルアセタール樹脂スラリーの中和処理工程において、ポリビニルアセタール樹脂の粒子同士の合着が阻止され、もしくは合着が発生する前に、生成した中和塩及び残存中和剤を洗い流すものであるためポリビニルアセタール樹脂の粒子に付着し、もしくは該粒子内に取り込まれた中和塩及び残存中和剤は極めて微量となり、繰り返し行われる中和、水洗工程によって、中和塩及び残存中和剤等の夾雑量は、より低レベルとなって、半導体素子等の電子部品等に供されるセラミックス類のバインダー等として高い性能を発揮し得るものとなるのである。
【００２４】
請求項２記載の発明のポリビニルアセタール樹脂の製造方法は、上述のように構成されているので、前記する効果を奏すると共に、先の中和水洗によって殆ど除去され、僅かに残存する酸触媒は、中和恒温時のポリビニルアセタール樹脂のＴｇ以上の温度において新たな中和剤によって中和処理されるので、殆ど完全に中和され、水洗によってポリビニルアセタール樹脂より除去される。
【００２５】
上記中和処理においてポリビニルアセタール樹脂は、そのＴｇ以上の中和恒温域の温度に曝されるので、該樹脂粒子同士の合着の発生はあるが、既に繰り返し行われた中和、水洗工程の後であるので、合着粒子内に一部取り込まれる中和塩等の夾雑物も極微量となっていて、水洗、乾燥後のポリビニルアセタール樹脂粒子は、残存中和塩及び残存中和剤量は極微量となっているのである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polyvinyl acetal resin.
[0002]
[Prior art]
Polyvinyl acetal resins represented by polyvinyl butyral resins are widely used in a wide range of fields such as paints, adhesives, safety glass interlayers and the like due to their excellent adhesion.
These polyvinyl acetal resins can be obtained by condensation reaction of polyvinyl alcohol and aldehydes, and as a production method thereof, polyvinyl alcohol is dispersed in an organic solvent, an acid catalyst is used, an aldehyde compound is added and reacted, After the polyvinyl acetal resin is precipitated from the generated polyvinyl acetal resin solution, the reaction proceeds in the aqueous phase in the presence of an acid catalyst or a dissolving method that is washed with water and dried, and the generated polyvinyl acetal resin loses solubility. There are known precipitation methods in which particles are precipitated in the form of particles and separated from the aqueous solvent in the reaction system. Since the above precipitation method can obtain a powdery polyvinyl acetal resin from an aqueous solution in a single step, the dissolution method requires an extra step of precipitating the polyvinyl acetal resin from the organic solvent solution of the generated polyvinyl acetal resin. Compared to, the number of steps is simple and easy, and it is evaluated as a method showing higher productivity.
[0003]
However, in the precipitation method, the reaction temperature becomes high and the particles of the generated polyvinyl acetal resin are likely to be coarsened. As a result, a large amount of the used acid catalyst is taken into the coarsened particles of the polyvinyl acetal resin. Become.
[0004]
Contamination of the residue such as the acid catalyst is particularly problematic when the polyvinyl acetal resin is used for a binder such as a ceramic electronic component, and the quality of the polyvinyl acetal resin is deteriorated. In order to avoid this, the condensation reaction described above is carried out at a relatively low temperature, and the resulting polyvinyl acetal resin is finely divided.
[0005]
However, it is difficult to separate the polyvinyl acetal resin containing no impurities such as the above-mentioned acid catalyst from the resulting slurry-like product by washing with water, even if the production system of polyvinyl acetal resin is made into fine particles. A neutralization step is incorporated in
That is, neutralize the acid catalyst in the mother liquor of the slurry product obtained by the condensation reaction described above, or neutralize the acid catalyst, or wash with water to reduce the concentration of the acid catalyst, and then add the neutralizer. Then, the neutralized salt and the remaining neutralizing agent are washed with water and dried to produce a particulate polyvinyl acetal resin.
[0006]
However, in the neutralization reaction of the acid catalyst, the particulate polyvinyl acetal resin obtained by the heat of reaction becomes a temperature in the neutral temperature isothermal region above the glass transition temperature (hereinafter abbreviated as Tg), and the particle Adhesion occurs, and the neutralized salt and the remaining neutralizing agent are partially taken into the coalesced particles. In the subsequent washing treatment, the neutralized salt and the like incorporated into these coalesced particles are completely removed. It becomes difficult to remove by washing.
If the amount of the neutralizing agent added is adjusted so as to lower the temperature in the neutralization constant temperature region of the neutralization reaction, the acid catalyst remains, which causes another quality problem of the polyvinyl acetal resin.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above facts, and its object is to provide a neutral salt or the like produced in the process of neutralizing the acid catalyst in the polyvinyl acetal resin slurry produced by the condensation reaction described above. Another object of the present invention is to provide a method for producing an excellent polyvinyl acetal resin that suppresses the incorporation into polyvinyl acetal resin particles and has a small content of contaminating electrolyte.
[0008]
[Means for Solving the Problems]
The method for producing a polyvinyl acetal resin according to the first aspect of the invention comprises neutralizing and washing with water a polyvinyl acetal resin product obtained by condensation reaction of polyvinyl alcohol and aldehydes in an aqueous phase in the presence of an acid catalyst. A method for producing a polyvinyl acetal resin, wherein the neutralization and water washing steps are repeated a plurality of times, and the initial neutralization reaction is performed by the obtained polyvinyl acetal resin product having a glass transition temperature of the resin product. Will be implemented as soon as
[0009]
The method for producing a polyvinyl acetal resin according to claim 2 is the method for producing a polyvinyl acetal resin according to claim 1, wherein the neutralization reaction performed after the first neutralization water washing is obtained. This is performed after reaching a temperature equal to or higher than the glass transition temperature of the resin.
[0010]
The polyvinyl alcohol and aldehydes used in the method for producing the polyvinyl acetal resin of the present invention are particularly limited as long as they are acetalized by a condensation reaction in the aqueous phase in the presence of an acid catalyst, and a polyvinyl acetal resin can be obtained therefrom. It is not something.
The acid catalyst is not particularly limited as long as it favorably catalyzes the acetalization reaction.
[0011]
In the method for producing a polyvinyl acetal resin of the present invention, the above neutralization and water washing steps that are repeated a plurality of times indicate that the neutralization treatment is performed and the water washing treatment step is performed at least twice. However, after reducing the acid catalyst concentration by washing with water first, the neutralizing agent is added, and even if the washing treatment is performed multiple times for one neutralization treatment, From the content of the neutralization treatment, the neutralization and water washing steps are counted as one time.
[0012]
The method for producing a polyvinyl acetal resin according to the first aspect of the invention comprises neutralizing and washing with water a polyvinyl acetal resin product obtained by condensation reaction of polyvinyl alcohol and aldehydes in an aqueous phase in the presence of an acid catalyst. The method for producing a polyvinyl acetal resin, wherein the neutralization and water washing steps are repeated a plurality of times, and the initial neutralization reaction is such that the obtained polyvinyl acetal resin product reaches the Tg of the resin product. Since the coalescence of the polyvinyl acetal resin particles is prevented, or before the coalescence occurs, the neutralized salt and the remaining neutralizing agent are washed away. Therefore, the neutralized salt and residual neutralizing agent adhering to the particles of the polyvinyl acetal resin or taken into the particles become very small amounts, and the neutralized salt and residual neutralizing agent are repeatedly subjected to neutralization and water washing steps. The amount of impurities such as these becomes a lower level and can exhibit high performance as a binder for ceramics used for electronic parts such as semiconductor elements.
[0013]
The method for producing a polyvinyl acetal resin according to claim 2 is the method for producing a polyvinyl acetal resin according to claim 1, wherein the neutralization reaction performed after the first neutralization water washing is obtained. Since it is carried out after reaching a temperature equal to or higher than the Tg of the resin, the acid catalyst which is almost removed by the initial neutralization water washing and slightly remains is also at a temperature equal to or higher than the Tg of the polyvinyl acetal resin at the neutral temperature. Since it is neutralized by a new neutralizing agent, it is almost completely neutralized and removed from the polyvinyl acetal resin by washing with water.
[0014]
In the neutralization treatment, since the polyvinyl acetal resin is exposed to a temperature in the neutralization constant temperature region of Tg or higher, there is an occurrence of coalescence of the resin particles, but the neutralization and water washing steps that have already been repeated are performed. Since it is later, the impurities such as neutralized salts partially incorporated in the coalesced particles are also in a very small amount, and the residual neutralized salts and remaining in the polyvinyl acetal resin particles after washing and drying The amount of the hydrating agent is extremely small.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described below, but the present invention is not limited to these examples.
[0016]
(Example 1)
By a conventional method, 283 g of polyvinyl alcohol having a saponification degree of 97.5% and a polymerization degree of 360 was added to 2657 g of pure water and dissolved by stirring. To the obtained aqueous polyvinyl alcohol solution, 364 g of hydrochloric acid having a concentration of 35% by weight and 196 g of n-butyraldehyde were added to carry out an acetalization reaction to obtain a polyvinyl acetal resin slurry composed of white fine particles. The apparent particle diameter of the obtained polyvinyl acetal resin fine particles was 10 to 20 μm, the degree of acetalization was 74 mol%, and Tg was 61 ° C.
[0017]
After washing with water until the chlorine content in the obtained polyvinyl acetal resin slurry mother liquor is 10 ppm and reducing the acid catalyst concentration, 4000 parts by weight of the polyvinyl acetal resin slurry becomes 10% by weight of the polyvinyl acetal resin slurry concentration. Then, 4 parts by weight of soda ash was added, and the mixture was heated with stirring until the temperature of the neutralization treatment system reached 61 ° C.
When the temperature of the neutralization system reached 61 ° C., the neutralized salt generated, the residual neutralizing agent, and the like were removed by immediately washing with water.
The chlorine content in the polyvinyl acetal resin slurry mother liquor after the first neutralization and water washing was 10 ppm, and the sodium content was 6 ppm.
[0018]
Next, 4000 parts by weight of the first neutralized and water-washed polyvinyl acetal resin slurry is adjusted so that the concentration of the polyvinyl acetal resin slurry is 10% by weight, and 0.5 parts by weight of soda ash is added. Then, the mixture was heated with stirring until the temperature of the neutralization treatment system reached 65 ° C., and the neutralization constant temperature was set at 3 hours, followed by washing with water to remove the produced neutralized salt and residual neutralizing agent.
The chlorine content in the polyvinyl acetal resin slurry mother liquor after the secondary neutralization and water washing was 10 ppm, and the sodium content was 8 ppm.
The polyvinyl acetal resin slurry subjected to the secondary neutralization and water washing treatment was dried to prepare a white fine particle-like polyvinyl acetal resin.
The apparent particle diameter of the obtained polyvinyl acetal resin was 80 to 100 μm, the chlorine content was 59 ppm, and the sodium content was 46 ppm.
[0019]
(Comparative Example 1)
The first neutralization in Example 1, the temperature of the neutralization treatment system of the water washing treatment was changed from 61 ° C. to 65 ° C., and after the neutralization constant temperature was 3 hours, the water washing treatment was performed. In the same manner as in Example 1, neutralization and water washing treatment were performed, and after a single neutralization and water washing treatment, a white fine particle-like polyvinyl acetal resin was produced through a drying step.
The chlorine content in the polyvinyl acetal resin slurry mother liquor after the neutralization and washing treatment was 8 ppm, and the sodium content was 7 ppm. Moreover, the apparent particle diameter of the obtained polyvinyl acetal resin was 80 to 100 μm, the chlorine content was 320 ppm, and the sodium content was 300 ppm.
[0020]
(Example 2)
By a conventional method, 322 g of polyvinyl alcohol having a saponification degree of 94.8% and a polymerization degree of 820 was added to 2597 g of pure water, and dissolved by stirring. To the obtained aqueous polyvinyl alcohol solution, 364 g of hydrochloric acid having a concentration of 35% by weight and 217 g of n-butyraldehyde were added to carry out an acetalization reaction to obtain a polyvinyl acetal resin slurry composed of white fine particles. The obtained polyvinyl acetal resin fine particles had an apparent particle diameter of 10 to 20 μm, an acetalization degree of 74 mol%, and a Tg of 60 ° C.
[0021]
Subsequent steps are the same as in Example 1 except that the heating temperature at the time of neutralization in the first neutralization and water washing step is changed to 60 ° C. The second neutralization, water washing step and drying step. After that, a white fine particle-like polyvinyl acetal resin was produced.
The chlorine content in the polyvinyl acetal resin slurry mother liquor after the first neutralization and water washing is 8 ppm, the sodium content is 6 ppm, the second neutralization, the chlorine content in the polyvinyl acetal resin slurry mother liquor after the water washing The amount was 9 ppm and the sodium content was 8 ppm.
Moreover, the apparent particle diameter of the obtained polyvinyl acetal resin was 80 to 100 μm, the chlorine content was 120 ppm, and the sodium content was 96 ppm.
[0022]
(Comparative Example 2)
The temperature of the neutralization treatment system of the first neutralization and washing treatment of Example 2 was changed from 60 ° C. to 65 ° C., and the neutralization constant temperature was changed to 3 hours, and then the washing treatment was performed. In the same manner as in Example 1, neutralization and water washing treatment were performed, and after a single neutralization and water washing treatment, a white fine particle-like polyvinyl acetal resin was produced through a drying step.
The chlorine content in the polyvinyl acetal resin slurry mother liquor after neutralization and water washing treatment was 10 ppm, and the sodium content was 8 ppm. Moreover, the apparent particle diameter of the obtained polyvinyl acetal resin was 80 to 100 μm, the chlorine content was 420 ppm, and the sodium content was 390 ppm.
[0023]
【The invention's effect】
Since the method for producing a polyvinyl acetal resin according to the first aspect of the present invention is configured as described above, a polyvinyl acetal obtained by subjecting a polyvinyl alcohol and an aldehyde to a condensation reaction in an aqueous phase in the presence of an acid catalyst. In the neutralization process of the resin slurry, since the coalescence of the particles of the polyvinyl acetal resin is prevented or before the coalescence occurs, the produced neutralized salt and the remaining neutralizing agent are washed away, so the polyvinyl acetal resin The amount of neutralized salt and residual neutralizing agent adhering to or taken into the particles is extremely small, and the amount of contamination such as neutralized salt and residual neutralizing agent is reduced by repeated neutralization and washing steps. , It becomes a lower level, and can exhibit high performance as a binder of ceramics used for electronic parts such as semiconductor elements. A.
[0024]
Since the production method of the polyvinyl acetal resin of the invention according to claim 2 is configured as described above, the above-mentioned effect is achieved, and the acid catalyst which is almost removed by the previous neutralization water washing and slightly remains is: Since neutralization is performed with a new neutralizing agent at a temperature equal to or higher than Tg of the polyvinyl acetal resin at the time of neutralization and constant temperature, it is almost completely neutralized and removed from the polyvinyl acetal resin by washing with water.
[0025]
In the neutralization treatment, since the polyvinyl acetal resin is exposed to a temperature in the neutralization constant temperature region of Tg or higher, there is an occurrence of coalescence of the resin particles, but the neutralization and water washing steps that have already been repeated are performed. Since it is later, impurities such as neutralized salt partially incorporated into the coalesced particles are also in a very small amount, and the polyvinyl acetal resin particles after washing and drying are the amount of residual neutralized salt and residual neutralizing agent. Is extremely small.
Claims (2)
上記中和、水洗工程は、複数回繰り返して行われ、
初回の中和工程は、加熱を行いながら、得られたポリビニルアセタール樹脂生成物のガラス転移温度に達するまで行い、前記初回の中和工程の終了後、直ちに初回の水洗工程を行う
ことを特徴とするポリビニルアセタール樹脂の製造方法。A method for producing a polyvinyl acetal resin comprising neutralizing and washing a polyvinyl acetal resin product obtained by condensation reaction of polyvinyl alcohol and aldehydes in an aqueous phase in the presence of an acid catalyst,
The neutralization and water washing steps are repeated a plurality of times,
The first neutralization step is performed while heating until reaching the glass transition temperature of the obtained polyvinyl acetal resin product, and immediately after the first neutralization step, the first water washing step is performed. The manufacturing method of the polyvinyl acetal resin characterized by the above-mentioned.
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| JP26603099A JP4275820B2 (en) | 1999-09-20 | 1999-09-20 | Method for producing polyvinyl acetal resin |
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| JP26603099A JP4275820B2 (en) | 1999-09-20 | 1999-09-20 | Method for producing polyvinyl acetal resin |
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| JP4012480B2 (en) | 2003-03-28 | 2007-11-21 | Ａｚエレクトロニックマテリアルズ株式会社 | Fine pattern formation aid and process for producing the same |
| US6919416B2 (en) * | 2003-04-11 | 2005-07-19 | E. I. Du Pont De Nemours And Company | Acetoacetylated polyvinyl polymers |
| JP5588091B2 (en) * | 2007-03-01 | 2014-09-10 | 積水化学工業株式会社 | Polyvinyl acetal resin and method for producing the same |
| US7960503B2 (en) * | 2009-05-26 | 2011-06-14 | Solutia, Inc. | Continuous washing of poly(vinyl butyral) |
| EP2554578B1 (en) * | 2010-03-31 | 2018-11-21 | Kuraray Co., Ltd. | Polyvinyl acetal film and uses thereof |
| JP5940301B2 (en) * | 2010-09-28 | 2016-06-29 | 株式会社クラレ | Polyvinyl acetal resin for thermoforming |
| US11374222B2 (en) | 2015-03-20 | 2022-06-28 | Sekisui Chemical Co., Ltd. | Composition for lithium secondary battery electrodes |
| CN108028387B (en) | 2016-04-01 | 2022-06-28 | 积水化学工业株式会社 | Composition for lithium secondary battery electrode |
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