JP2005190747A5

JP2005190747A5 -

Info

Publication number: JP2005190747A5
Application number: JP2003428572A
Authority: JP
Filing date: 2003-12-25
Publication date: 2006-03-23
Anticipated expiration: 2023-12-25

Description

本発明は、（ａ）脂肪族共役ジエン系単量体からなる構成単位５０〜８０重量％、（ｂ）エチレン系不飽和カルボン酸単量体からなる構成単位２０〜５０重量％、ならびに（ｃ）上記脂肪族共役ジエン系単量およびエチレン系不飽和カルボン酸と共重合可能な他の単量体からなる構成単位０〜３０重量％［ただし、（ａ）＋（ｂ）＋（ｃ）＝１００重量％］からなる共重合体ラテックスを主成分とする２次電池電極用増粘結着剤に関する。
また、本発明は、本発明の２次電池電極用増粘結着剤に、電極活物質を混合、分散させて得られる電池電極用組成物を集電材に塗布して得られることを特徴とする２次電池電極に関する。 The present invention includes (a) 50 to 80 % by weight of a structural unit composed of an aliphatic conjugated diene monomer, (b) 20 to 50 % by weight of a structural unit composed of an ethylenically unsaturated carboxylic acid monomer, and (c ) 0 to 30 % by weight of a structural unit composed of the above aliphatic conjugated diene monomer and another monomer copolymerizable with an ethylenically unsaturated carboxylic acid [where (a) + (b) + (c) = 100 wt%] of the present invention relates to a thickening binder for secondary battery electrodes, the main component of which is a copolymer latex.
Further, the present invention is characterized in that it is obtained by applying a battery electrode composition obtained by mixing and dispersing an electrode active material to the thickening binder for secondary battery electrodes of the present invention to a current collector. The present invention relates to a secondary battery electrode.

以下に本発明を詳細に説明する。
本発明の２次電池電極用増粘結着剤は、（ａ）脂肪族共役ジエン系単量体からなる構成単位５０〜８０重量％、（ｂ）エチレン系不飽和カルボン酸単量体からなる構成単位２０〜５０重量％、ならびに（ｃ）上記脂肪族共役ジエン系単量およびエチレン系不飽和カルボン酸と共重合可能な他の単量体からなる構成単位０〜３０重量％［ただし、（ａ）＋（ｂ）＋（ｃ）＝１００重量％］からなる共重合体ラテックスを主成分とする。
ここで、当該共重合体ラテックスは、通常、（ａ）脂肪族共役ジエン系単量体５０〜８０重量％、（ｂ）エチレン系不飽和カルボン酸単量体２０〜５０重量％、および（ｃ）上記単量体（ａ）〜単量体（ｂ）と共重合可能な他の単量体０〜３０重量％[ただし、(ａ)＋（ｂ）＋（ｃ）＝１００重量％]からなる単量体成分を乳化重合して得られる。 The present invention is described in detail below.
The thickening binder for secondary battery electrodes of the present invention comprises (a) 50 to 80 % by weight of a structural unit composed of an aliphatic conjugated diene monomer, and (b) an ethylenically unsaturated carboxylic acid monomer. 20 to 50 % by weight of a structural unit, and (c) 0 to 30 % by weight of a structural unit composed of the above aliphatic conjugated diene monomer and another monomer copolymerizable with an ethylenically unsaturated carboxylic acid [where ( a) + (b) + (c) = 100 wt%] as a main component.
Here, the copolymer latex is usually (a) 50 to 80 % by weight of an aliphatic conjugated diene monomer, (b) 20 to 50 % by weight of an ethylenically unsaturated carboxylic acid monomer, and (c) ) From the above monomer (a) to other monomer copolymerizable with monomer (b) 0 to 30 % by weight [however, (a) + (b) + (c) = 100% by weight] Obtained by emulsion polymerization.

上記の単量体成分の組成は、（ａ）脂肪族共役ジエン系単量体５０〜８０重量％、（ｂ）エチレン系不飽和カルボン酸単量体２０〜５０重量％、ならびに（ｃ）上記（a）構成単位および（ｃ）構成単位と共重合可能な他の単量体０〜３０重量％［ただし、（ａ）＋（ｂ）＋（ｃ）＝１００重量％］からなる。
かかる（ａ）脂肪族共役ジエン系単量体は、電極活物質どうしの密着性および電極活物質と金属集電体との密着性発現に必須の成分であり、その使用割合は全単量体成分に対して、５０〜８０重量％である。この（ａ）成分が５０重量％未満であると、密着性に劣り、一方、８０重量％を超えると分散安定性に劣る。
また、（ｂ）エチレン系不飽和カルボン酸単量体の使用量は、全単量体成分に対して２０〜５０重量％である。（ｂ）成分が２０重量％未満では、増粘性に劣る結果、活物質の分散安定性に劣り、一方、５０重量％を超えると、密着性に劣る。
さらに、（ｃ）成分は、主として目的に応じた硬さ、電解質の膨潤性などの制御のために使用するものであり、その使用割合は０〜３０重量％である。 The composition of the monomer component is as follows: (a) 50-80 % by weight of aliphatic conjugated diene monomer, (b) 20-50 % by weight of ethylenically unsaturated carboxylic acid monomer, and (c) above (A) Constituent unit and (c) 0 to 30 % by weight of another monomer copolymerizable with the constituent unit [provided that (a) + (b) + (c) = 100% by weight].
The (a) aliphatic conjugated diene monomer is an essential component for the adhesion between the electrode active materials and the adhesion between the electrode active material and the metal current collector. 50 to 80 % by weight based on the components. When the component (a) is less than 50 % by weight, the adhesion is inferior, whereas when it exceeds 80 % by weight, the dispersion stability is inferior.
Moreover, the usage-amount of (b) ethylenically unsaturated carboxylic acid monomer is 20 to 50 weight% with respect to all the monomer components. If the component (b) is less than 20 % by weight, the viscosity is inferior, resulting in poor dispersion stability of the active material. On the other hand, if it exceeds 50 % by weight, the adhesion is poor.
Furthermore, the component (c) is used mainly for controlling the hardness according to the purpose, the swelling property of the electrolyte, and the use ratio thereof is 0 to 30 % by weight.

Claims

(A) 50-80 % by weight of a structural unit comprising an aliphatic conjugated diene monomer, (b) 20-50 % by weight of a structural unit comprising an ethylenically unsaturated carboxylic acid monomer, and (c) the above aliphatic Constituent units consisting of a conjugated diene monomer and another monomer copolymerizable with an ethylenically unsaturated carboxylic acid, 0 to 30 % by weight [where (a) + (b) + (c) = 100% by weight] A thickening binder for a secondary battery electrode, the main component of which is a latex copolymer.

The thickening binder for secondary battery electrodes according to claim 1 , wherein (a) is a structural unit composed of 1,3-butadiene and (b) is a structural unit composed of methacrylic acid.

The thickening binder for secondary battery electrodes according to claim 1 or 2, wherein the glass transition temperature of the copolymer constituting the copolymer latex is -60 to 20 ° C.

The thickening binder for secondary battery electrodes according to any one of claims 1 to 3, wherein the copolymer constituting the copolymer latex has a weight average molecular weight of 3,000 to 2,000,000.

A battery electrode composition obtained by mixing and dispersing an electrode active material in the thickening binder for a secondary battery electrode according to any one of claims 1 to 4 , is obtained by applying to a current collector. Secondary battery electrode.

A battery electrode composition comprising the binder for a secondary battery electrode according to any one of claims 1 to 4 and an electrode active material is applied in a slurry form to a current collector, heated, and dried. The manufacturing method of the secondary battery electrode of Claim 5 .