JP2005028400A - Brazing binder and heat exchanger member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brazing binder which prevents the detachment of a brazing material caused by the deformation during working before brazing and a working fluid, and does not deteriorate brazing properties by being decomposed and evaporating during the brazing. <P>SOLUTION: The brazing binder is composed of a (meta) acrylic acid ester copolymer including a constituent unit derived from a mono (meta) acrylate of (poly) ethylene glycol substituted with a specific group and a constituent unit derived from an acid radical-containing ethylenically unsaturated monomer. A binder composition comprises the brazing binder and 0.1-50 pts.wt of crosslinker, based on 100 pts.wt. of the brazing binder. A brazing composition comprising the binder composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００９】
［一般式（１）において、Ｒ^１は水素又はメチル基、Ｒ^２は炭素数１〜１８のアルキル基、炭素数６〜１８のアリール基、又は炭素数７〜２０のアルアルキル基を表し、ｎは１〜１００の整数を表す。）
【００１０】
また、本発明のバインダ組成物は、前記ろう付け用バインダと、該ろう付け用バインダ１００重量部あたり０．１〜５０重量部の架橋剤とを含有することを特徴とする。
また、本発明のろう付け用組成物は、アルミニウム材用ろう材と前記バインダ組成物とが混合されてなることを特徴とする。
また、本発明のろう付け用組成物は、フラックスと、前記バインダ組成物と、あるいはさらにアルミニウム用ろう材とが混合されてなることを特徴とする。
【００１１】
また、本発明のペーストは、前記バインダ組成物又は前記のいずれかのろう付け用組成物が炭素数１〜８のアルコールに混合されてなることを特徴とする。
また、本発明の熱交換器部材は、前記バインダ組成物又は前記のいずれかのろう付け用組成物又は前記ペーストが表面の少なくとも一部に塗布されてなることを特徴とする。
【００１２】
【発明の実施の形態】
本発明で用いられる一般式（１）で表される（メタ）アクリル酸エステル（ａ１）において、Ｒ^２は炭素数１〜１８、好ましくは１〜６のアルキル基、炭素数６〜１８、好ましくは６〜１０のアリール基、又は炭素数７〜２０、好ましくは７〜１１のアルアルキル基を表し、アルキル基としては、メチル基、エチル基、ｎ−プロピル基、ｉ−プロピル基、ｎ−ブチル基、ｉ−ブチル基、ｔ−ブチル基、ペンチル基、ヘキシル基、シクロヘキシル基、ヘプチル基、メチルシクロヘキシル基、オクチル基、ジメチルシクロヘキシル基、ノニル基、デシル基、デカリル基、ウンデシル基、ラウリル基、トリデシル基、テトラデシル基、ペンタデシル基、ヘキサデシル基、ヘプタデシル基、オクタデシル基等を例示できる。また、アリール基としては、フェニル基、トリル基、キシリル基、エチルフェニル基、プロピルフェニル基、ブチルフェニル基、ナフチル基、ペンチルフェニル基、ヘキシルフェニル基、オクチルフェニル基、ノニルフェニル基等を例示できる。アルアルキル基としてはベンジル基、メチルベンジル基、フェニルエチル基、ナフチルメチル基等を例示できる。
なお、本発明においては、（メタ）アクリル酸とはアクリル酸とメタクリル酸の一方又は両方を示す。
（メタ）アクリル酸エステル（ａ１）においてはエステル部分の（ポリ）オキシエチレン鎖の末端がアルキル基、アリール基、アルアルキル基で封鎖されているので、ＯＨ末端の場合より、ろう材への相互作用が少なく、炭化物発生による黒色残渣の発生を抑制できる。かつ、バインダの極性を調整し、加工油への耐性を付与できるという特徴を有する。
代表的な（ａ１）としては、エトキシポリエチレングリコールモノアクリレート、エトキシポリエチレングリコールモノメタクリレート、メトキシポリエチレングリコールモノアクリレート、メトキシポリエチレングリコールモノメタクリレート等が挙げられる。
【００１３】
また、本発明で用いられる酸基含有エチレン性不飽和単量体（ａ２）において、酸基はカルボン酸基、リン酸基、又はスルホン酸基から選ばれる１種以上であることが好ましい。
カルボン酸基含有エチレン性不飽和単量体としては、（メタ）アクリル酸、ビニル酢酸、アリル酢酸、マレイン酸、フマル酸、イタコン酸等を例示でき、これらの中では（メタ）アクリル酸が好ましく用いられる。
リン酸基含有エチレン性不飽和単量体としては、エチレンホスホン酸等を例示でき、スルホン酸基含有エチレン性不飽和単量体としてはエチレンスルホン酸等を例示できる。酸基含有エチレン性不飽和単量体は１種のみを用いてもよく２種以上の組み合わせであってもよい。
酸基含有エチレン性不飽和単量体（ａ２）の酸基がカルボン酸基であると、粉末ろうとのバインダ力が向上するという効果を有し、リン酸基であると、アルミ基材との密着性が向上するという効果を有し、スルホン酸基であると、加工性（曲げ、切削、プレス加工等）が向上するという効果を有するので、酸基含有エチレン性不飽和単量体（ａ２）の酸基は、カルボン酸基、リン酸基、スルホン酸基から選ばれる１種以上であることが好ましい。
【００１４】
（メタ）アクリル酸エステル系共重合体（Ａ）は、上記（ａ１）に由来する構成成分、上記（ａ２）に由来する構成成分の他、必要に応じてこれら（ａ１）、（ａ２）と共重合可能な単量体に由来する構成成分を含むことができる。
このような単量体としては、（メタ）アクリル酸メチル、（メタ）アクリル酸エチル、（メタ）アクリル酸プロピル、（メタ）アクリル酸イソプロピル、（メタ）アクリル酸ブチル、（メタ）アクリル酸イソブチル、（メタ）アクリル酸ヘキシル、（メタ）アクリル酸−２−エチルヘキシル、（メタ）アクリル酸ラウリル、（メタ）アクリル酸シクロヘキシル、（メタ）アクリル酸ベンジル、（メタ）アクリル酸デシル、（メタ）アクリル酸イソデシル、（メタ）アクリル酸イソボルニル等の（メタ）アクリル酸エステル、アクリロニトリル、スチレン等を例示できる。
【００１５】
（メタ）アクリル酸エステル系共重合体（Ａ）中に占める上記（ａ１）に由来する構成単位は５〜５０重量％、より好ましくは１０〜４０重量％であることが好ましい。（ａ１）に由来する構成単位を５重量％以上とすることで、バインダのろう付け時の分解蒸発性が良好となり、加工油への耐性が向上するので好ましく、５０重量％以下にすることで、炭化物による黒色残渣を少なくすることができるので好ましい。
また、（メタ）アクリル酸エステル系共重合体（Ａ）中に占める上記（ａ２）に由来する構成単位は０．１〜１０重量％、より好ましくは０．５〜５重量％含有することが好ましい。（ａ２）に由来する構成単位を０．１重量％以上とすると、バインダの粉末ろう及びアルミ基材との密着性が向上するので好ましく、１０重量％以下にすることで、炭化物による黒色残渣を少なくすることができるので好ましい。
【００１６】
本発明において、（メタ）アクリル酸エステル系共重合体（Ａ）の重量平均分子量（スチレン換算）は、１０００〜１０００００であることが好ましい。重量平均分子量が１０００未満では加工油への耐性が低下する傾向にあり、１０００００を超えると、剥がれ発生などの加工性低下、ろう付け性の低下、黒色残渣の増加となる傾向にある。
本発明において、（メタ）アクリル酸エステル系共重合体（Ａ）のガラス転移温度（Ｔｇ）は０℃を超え、１００℃以下であることが好ましい。Ｔｇを０℃を超えるものとすることで、熱交換器部材のブロッキングを防止することができる。Ｔｇを１００℃以下とすることで、アルミニウム材用ろう材を浸漬により塗布する際にろう材の付着性を良好とすることができる。
【００１７】
本発明のろう付け用バインダは一般式（１）で示される（メタ）アクリル酸エステル（ａ１）と酸基含有エチレン性不飽和単量体（ａ２）とを共重合成分として含むので、アルミニウム材に対する密着性に優れ、このろう付け用バインダを用いてアルミニウム材用ろう材をろう付けした場合、ろう付け後の加工による部材の変形が生じてもろう材が脱落することなく、加工油と接触して膨潤、脱落することがない。また、ろう付け時にはろう付け温度に達する前に分解蒸発するのでろう付けを阻害することなく、ろう付け後の熱交換器の美観を損ねることがない。
【００１８】
次に本発明のバインダ組成物につき説明する。本発明のバインダ組成物は、前記ろう付け用バインダと、該ろう付け用バインダ１００重量部あたり０．１〜５０重量部の架橋剤とを含有する。
架橋剤は、酸基と反応する官能基を分子中に２つ以上有するものであり、このような架橋剤としてはＡｌ系、Ｆｅ系、Ｚｎ系に代表される金属キレート系化合物、オキサゾリン系化合物、エポキシ系化合物等を挙げることができ、これらの中では、金属キレート系化合物、オキサゾリン系化合物が好ましく用いられる。この架橋剤は１種のみを用いてもよいが、２種以上を併用することもできる。
本発明のバインダ組成物に架橋剤を含有させることにより、また、好ましくは加熱することにより、部材表面に塗布後にバインダを架橋させることができるので、加工油等による膨潤がなく、従って、アルミニウム材用ろう材塗布後にろう材が剥離脱落することがない。
架橋剤の使用量がろう付け用バインダ１００重量部あたり０．１重量部未満では、架橋剤の添加効果がなく、ろう付け前の加工時の素材の変形や、加工油による膨潤でろう材が剥がれやすくなる。逆に５０重量部を超えると、ろう付け時の分解蒸発が不充分となり、残渣として部材表面に残って、ろう付け性が低下したり、ろう付け後の熱交換器の美観を損なったりするおそれがある。
このバインダ組成物はろう付け用バインダと粉末状の架橋剤の混合物とするのが好ましい。
【００１９】
次に本発明のろう付け用組成物につき説明する。
本発明のろう付け用組成物はアルミニウム材用ろう材と前記バインダ組成物とが混合されてなる。
アルミニウム材用ろう材はろう付けされるアルミニウムあるいはアルミニウム合金よりも融点の低いアルミニウム合金が用いられ、通常、珪素−アルミニウム合金粉末が用いられる。
ろう付け組成物におけるアルミニウム材用ろう材とバインダ組成物の比率は、アルミニウム材用ろう材１００重量部あたり、バインダ組成物１〜１００重量部であることが好ましい。バインダ組成物が上記下限未満であると、ろう付け前の部材加工時にアルミニウム材用ろう材が剥離しやすくなる。バインダ組成物が上記上限を超えた量であると、ろう付け時の分解蒸発が不充分となり、残渣として部材表面に残って、ろう付け性が低下したり、ろう付け後の熱交換器の美観を損なったりするおそれがある。
【００２０】
また、本発明のろう付け用組成物は、フラックスと、前記バインダ組成物とが混合されたものであってもよい。
本発明において用いられるフラックスは、フラックスろう付け法で用いられるものであればどのようなものも用いることができ、例えば、塩化ナトリウム、塩化カリウム、塩化リチウム、塩化亜鉛、フッ化リチウムフッ化アルミン酸カリウムなどから選ばれる２種以上の混合物を例示できる。フラックスに対するバインダ組成物の比率は、フラックス１００重量部あたり、バインダ組成物が１〜１００重量部であることが好ましい。
また、本発明のろう付け用組成物は、フラックスと前記バインダ組成物とアルミニウム材用ろう材とが混合されてなるものであってもよい。
この場合のフラックスとアルミニウム材用ろう材の比率は通常フラックスろう付け法で用いられる比率とする。バインダ組成物のアルミニウム用ろう材に対する比率はアルミニウム材用ろう材１００重量部あたり、バインダ組成物１〜１００重量部であることが好ましい。バインダ組成物が上記下限未満であると、ろう付け前の部材加工時にアルミニウム材用ろう材が剥離しやすくなる。バインダ組成物が上記上限を超えた量であると、ろう付け時の分解蒸発が不充分となり、残渣として部材表面に残って、ろう付け性が低下したり、ろう付け後の熱交換器の美観を損なったりするおそれがある。
【００２１】
本発明のペーストは、前記バインダ組成物又は前記のいずれかのろう付け用組成物が炭素数１〜８のアルコールに混合されてなる。
このアルコールとしては、メタノール、エタノール、ｎ−プロパノール、イソプロパノール、ｎ−ブタノール、ｉ−ブタノール、ｔ−ブタノール、ペンタノール、ヘキサノール、ラウリルアルコール、オクタノール、エチレングリコールモノメチルエーテル、エチレングリコールモノエチルエーテル、エチレングリコールモノブチルエーテル、ジエチレングリコールモノメチルエーテル、ジエチレングリコールモノエチルエーテル、ジエチレングリコールモノブチルエーテル、プロピレングリコールモノメチルエーテル、プロピレングリコールモノエチルエーテル、プロピレングリコールモノブチルエーテル、ジプロピレングリコールモノエチルエーテル、ジプロピレングリコールモノエチルエーテル等を例示できる。
バインダ組成物あるいはろう付け用組成物に対するアルコールの添加量は、バインダ組成物あるいはろう付け用組成物１００重量部あたり、アルコール１０〜１０００重量部であることが好ましい。アルコールとして、低引火点のアルコールを用いた場合は、火気のないところでペーストをろう付けする部材に塗布し、アルコールを揮発させてから次の処理にかかるのが好ましい。
このようなペーストを用いると、アルミニウム材に対するバインダ組成物あるいはろう付け用組成物の濡れ性を向上させ、均一な塗布を実現することができる。
【００２２】
本発明の熱交換器用部材は前記バインダ組成物又は前記のいずれかのろう付け用組成物又は前記ペーストが表面の少なくとも一部に塗布されてなる。
この熱交換器用部材としては熱交換器用チューブ、フィン用部材等を例示できる。
前記バインダ組成物あるいはバインダ組成物にアルコールを混合してなるペーストが表面の少なくとも一部に塗布されてなる熱交換器用部材は、その上にアルミニウム材用ろう材を塗布すれば、その後にプレス加工しても部材変形によるろう材の脱落、加工油による膨潤・剥離がない。また、ろう材のろう付け温度より低い温度でバインダが分解蒸発するのでろう付けが容易にできる。
前記のいずれかのろう付け用組成物またはろう付け用組成物にアルコールを混合してなるペーストが表面の少なくとも一部に塗布されてなる熱交換器用部材は、これをプレス加工しても部材変形によるろう材の脱落、加工油による膨潤・剥離がなく、ろう材のろう付け温度より低い温度でバインダが分解蒸発するのでろう付けが容易にできる。
【００２３】
【実施例】
以下に、実施例を用いて、本発明をさらに詳しく説明する。
なお、実施例、比較例においては、次の試験片を作成して、以下の評価を行った。
［試験片］
各実施例、比較例で得たろう付け用組成物を片面に塗布乾燥して固着させたアルミ板（３００３）を用いた。
［９０度曲げ加工耐性］
試験片のろう材が固着した面を外側にしてＲ１０で９０度曲げ加工し、曲げ加工した部位を指で擦り、剥離の有無を調査した。
○：剥離なし
×：剥離あり
［耐加工油性］
試験片を加工油に１時間浸漬後、ろう付け用組成物固着面の鉛筆引っ掻き試験を行い、塗膜の鉛筆硬度を測定した。
○：鉛筆硬度が４Ｂより高い
×：鉛筆硬度が４Ｂ以下
【００２４】
［ろう付け性］（図１を参照）
幅２５ｍｍ、長さ６０ｍｍ、厚さ１ｍｍの試験片１のろう付け用組成物塗布面の上に、ＳＵＳ３０４丸棒（φ１ｍｍ、長さ１５ｍｍ）からなるスペーサー２を置き、幅２５ｍｍ、長さ５５ｍｍ、厚さ１ｍｍのアルミニウム（３００３）製板３を一方の端がスペーサー２の上に乗り、他方の端が試験片１の上にあるように垂直に立てて置いてなる、図１に示す逆Ｔ字形隙間充填試験片を組み付け、ろう付けを行い、ろう付け性の評価を充填長さＬで行った。
○：充填長さＬ３０ｍｍ以上
×：充填長さＬ３０ｍｍ未満
［バインダ残渣発生状況］
ろう付け性評価で用いた試験片を目視で観察し、黒色残渣の有無を確認した。
○：残渣なし
×：残渣あり
【００２５】
（実施例１）
［ろう付け用バインダＡ１の調製］
攪拌装置、還流器、滴下ロート及び窒素導入管を備えた反応装置に、イソプロピルアルコール（溶媒）１０００重量部を入れて、窒素気流下で攪拌しながら８０℃まで昇温した。
次いで、メチルメタクリレート３００重量部、ｎ−ブチルメタクリレート４５０重量部、メトキシポリエチレングリコールモノメタクリレート（商品名：ブレンマーＰＭＥ−４００、日本油脂社製、一般式（１）におけるｎ≒９、Ｒ^１、Ｒ^２＝メチル、Ｍｗ≒４００）２５０重量部、メタクリル酸１０重量部、および重合開始剤としてアゾビスイソブチロニトリルを適量加えた混合物を２．０時間かけて滴下し、さらに１．０時間同温度に維持して重合を完結させ、ろう付け用バインダＡ１の溶液を得た。
Ａ１の重量平均分子量（ポリスチレン換算）は２４，０００、Ｔｇは５０℃であった。
【００２６】
［バインダ組成物（Ｂ１）及びろう付け用組成物（Ｃ１）の調製］
上記で得られたろう付け用バインダＡ１溶液の固形分１００重量部あたり、架橋剤としてオキサゾリジン系ポリマー溶液を固形分換算で２０重量部混合してバインダ組成物Ｂ１を得た。アルミニウム材用ろう材としてアルミニウム合金ＢＡ４０４５（Ａｌ−１０ｗｔ％Ｓｉ）からなる粉末ろうを１００重量部、フラックスとしてフッ化アルミニウムカリ塩を主成分とするフッ化物系フラックスを１０重量部、分散媒としてイソプロパノールを１００重量部混合してろう付け用組成物Ｃ１を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００２７】
（実施例２）
メタクリル酸１０重量部の代わりに同量の（２−メタクリロイロキシエチル）アシッドフォスフェート（共栄社化学社製）を用いた以外は実施例１と同様にしてろう付け用バインダＡ２を得た。
Ａ２の重量平均分子量は２０，０００、Ｔｇは４８℃であった。
得られたバインダＡ２を用いた以外は実施例１と同様にしてバインダ組成物Ｂ２及びろう付け用組成物Ｃ２を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００２８】
（実施例３）
メタクリル酸１０重量部の代わりに同量の２−アクリルアミド−２−メチルプロパンスルホン酸（東亞合成社製）を用いた以外は実施例１と同様にしてろう付け用バインダＡ３を得た。
Ａ３の重量平均分子量は１９，０００、Ｔｇは４９℃であった。
得られたバインダＡ３を用いた以外は実施例１と同様にしてバインダ組成物Ｂ３及びろう付け用組成物Ｃ３を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００２９】
（実施例４）
メトキシポリエチレングリコールモノメタクリレートとして、ブレンマーＰＭＥ−４００の代わりに同量のブレンマーＰＭＥ−１００（商品名、日本油脂社製、一般式（１）におけるｎ≒２、Ｒ^１＝メチル、Ｒ^２＝Ｈ、Ｍｗ≒１００）を用いた以外は実施例１と同様にしてろう付け用バインダＡ４を得た。
Ａ４の重量平均分子量は２２，０００、Ｔｇは４７℃であった。
得られたバインダＡ４を用いた以外は実施例１と同様にしてバインダ組成物Ｂ４及びろう付け用組成物Ｃ４を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００３０】
（実施例５）
重合開始剤の使用量を調整することにより、Ａ１と同一の組成であるが、重量平均分子量７５，０００、Ｔｇ５５℃のろう付け用バインダＡ５を得た。
得られたバインダＡ５を用いた以外は実施例１と同様にしてバインダ組成物Ｂ５及びろう付け用組成物Ｃ５を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００３１】
（実施例６）
メチルメタクリレート３００重量部、ｎ−ブチルメタクリレート４５０重量部の代わりにメチルメタクリレート５６０重量部、ｎ−ブチルメタクリレート１９０重量部を用いた以外は実施例１と同様にしてろう付け用バインダＡ６を得た。
Ａ６の重量平均分子量は２７，０００、Ｔｇは７９℃であった。
得られたバインダＡ６を用いた以外は実施例１と同様にしてバインダ組成物Ｂ６及びろう付け用組成物Ｃ６を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００３２】
（実施例７）
メトキシポリエチレングリコールモノメタクリレート（商品名：ブレンマーＰＭＥ−４００）の代わりに同量のメトキシポリエチレングリコールモノアクリレート（商品名：ブレンマーＡＭＥ−４００、日本油脂社製、ｎ≒９、Ｒ^１＝Ｈ、Ｒ^２＝メチル、Ｍｗ≒４００）を用いた以外は実施例１と同様にしてろう付け用バインダＡ７を得た。
Ａ７の重量平均分子量は２３，０００、Ｔｇは４９℃であった。
得られたバインダＡ７を用いた以外は実施例１と同様にしてバインダ組成物Ｂ７及びろう付け用組成物Ｃ７を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００３３】
（比較例１）
メトキシポリエチレングリコールモノメタクリレート（商品名：ブレンマーＰＭＥ−４００）の代わりに同量のポリエチレングリコールモノメタクリレート（商品名：ブレンマーＰＥ−３５０、日本油脂社製、ｎ≒８、Ｍｗ≒３５０）を用いた以外は実施例１と同様にしてろう付け用バインダＤ１を得た。
Ｄ１の重量平均分子量は２２，０００、Ｔｇは５３℃であった。
得られたバインダＤ１を用いた以外は実施例１と同様にしてバインダ組成物Ｅ１及びろう付け用組成物Ｆ１を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００３４】
（比較例２）
メトキシポリエチレングリコールモノメタクリレートを用いなかった以外は実施例１と同様にしてろう付け用バインダＤ２を得た。
Ｄ２の重量平均分子量は２６，０００、Ｔｇは４９℃であった。
得られたバインダＤ２を用いた以外は実施例１と同様にしてバインダ組成物Ｅ２及びろう付け用組成物Ｆ２を得た。
このろう付け用組成物を用いて試験片を作成し、９０度曲げ加工耐性、耐加工油性、ろう付け性の試験を行い、バインダ残渣発生状況も観察した。その結果を表１に示す。
【００３５】
【表１】

【００３６】
表１から明らかなように比較例１のろう付け組成物（Ｆ１）はろう付け用組成物塗布面に残渣が発生し、比較例２のろう付け組成物（Ｆ２）で、耐加工油性で加工油浸漬によりバインダが膨潤したのに対し、実施例で得たろう付け用組成物はいずれも９０度曲げ加工耐性、耐加工油性に優れ、ろう付け特性も優れ、バインダ残渣も発生しない、優れたろう付け用組成物であることがわかる。
【００３７】
【発明の効果】
以上から明らかなように、本発明のバインダを用いた場合、良好な加工性、耐加工油性、ろう付け性が得られ、かつ、バインダの残渣が発生しないため、製品の美観を損なうことがない。
【図面の簡単な説明】
【図１】逆Ｔ字形隙間充填試験片を組み付けたろう付け用組成物塗布板を示す。
【符号の説明】
１：試験片 ２：スペーサー ３：垂直板
Ｌ：充填長さ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a binder for brazing an aluminum material.
[0002]
[Prior art]
Aluminum and aluminum alloys (hereinafter also referred to as aluminum materials) are widely used for fins of heat exchangers such as room air conditioners and industrial heat exchangers because of their light weight, workability, and thermal conductivity.
The assembly manufacture of the heat exchanger using an aluminum material was performed by brazing the fin which consists of a brazing sheet which clad the brazing material to the aluminum material with respect to the tube which consists of a multi-hole pipe | tube.
However, conventionally, when brazing a brazing material to an aluminum material, since a brazing material is used, a sheet in which the brazing material is clad on the entire surface of the aluminum material is used. From the point of view, the brazing material other than the brazing part was wasted and contributed to the high cost.
In recent years, heat exchangers, including those for automobiles, are strongly required to reduce costs, and cost reduction is a major point.
[0003]
Therefore, as one of the solutions, powder brazing is notable, in which an expensive brazing sheet is not used, and a brazing material powdered only on necessary portions is applied and brazed.
In this powder brazing, it is necessary to use a binder together in order to apply a brazing composition such as a powder brazing material or a flux to a brazing target portion of an aluminum material and fix it.
A member made of an aluminum material to which the brazing composition containing this binder is fixed is assembled for bending or cutting using a processing oil, drilling, thickness adjustment, etc. before being assembled as a heat exchanger. Various processing such as pressing is performed. At that time, the binder is also required to prevent the brazing composition from peeling off from the aluminum material.
Further, at the time of brazing heating after being assembled in the heat exchanger, it is also required that the binder is decomposed and evaporated before the powdered brazing material melts and flows, so that the brazing property is not hindered.
[0004]
As a brazing binder, there is a proposal for improving wettability to an aluminum material by using an aqueous solution of a saponified product of a specific methacrylate ester polymer (see, for example, Patent Document 1).
Moreover, as a thing with little dropout at the time of processing before brazing, a proposal of a binder mainly composed of a copolymer having an acid value of 50 or more including acrylic acid half ester of methacrylic acid ester and polyalkylene glycol (for example, Patent Document 2), a proposal of a binder mainly composed of a similar copolymer having a hydroxyl value of less than 60 and a glass transition temperature of 0 ° C. or lower (for example, see Patent Document 3), and the same purpose as above. There is also a proposal of a binder made of a methacrylic acid ester copolymer to which an oxysilane group-containing resin is added (see, for example, Patent Document 4).
Furthermore, there is also a proposal to use a polymer having a cationic polymerizable functional group as a binder that does not cause elution even when an organic solvent adheres in the heat exchanger manufacturing process (see, for example, Patent Document 5).
[0005]
[Patent Document 1]
JP 2000-153393 A
[Patent Document 2]
Japanese Patent Laid-Open No. 11-123588
[Patent Document 3]
Japanese Patent Laid-Open No. 11-10389
[Patent Document 4]
Japanese Unexamined Patent Publication No. 2000-687
[Patent Document 5]
JP 2000-79496 A
[0006]
[Problems to be solved by the invention]
However, the binders conventionally used as described above have problems to be solved, and the binders described in Patent Documents 1, 2, 3, and 5 cannot be decomposed and evaporated during brazing heating. Some carbonized and remained on the member surface as a black residue. Due to this residue, there is a problem that the brazing property is deteriorated or the beauty of the heat exchanger after brazing is impaired. Furthermore, the binders described in Patent Documents 1 to 3 also have a problem that the concern of swelling due to processing oil remains. In addition, the binder described in Patent Document 4 has a problem that peeling due to bending, cutting, pressing, or the like is a concern.
The present invention does not use an expensive glazing sheet, and is a binder suitable for the production of a brazing material that can be applied only to a necessary portion of a target base material, that is, a brazing material by deformation or processing oil during processing before brazing. It is an object of the present invention to provide a brazing binder that prevents falling off and decomposes and evaporates during brazing and does not impair brazing properties.
[0007]
[Means for Solving the Problems]
That is, the brazing binder of the present invention has a constitutional unit derived from the (meth) acrylic acid ester (a1) represented by the general formula (1) and an acid group-containing ethylenically unsaturated monomer (a2). It consists of the (meth) acrylic acid ester type copolymer (A) containing a unit, It is characterized by the above-mentioned.
[0008]
[Chemical 2]

[0009]
[In the general formula (1), R ¹ Is hydrogen or methyl group, R ² Represents an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, and n represents an integer of 1 to 100. )
[0010]
The binder composition of the present invention is characterized by containing the above-mentioned brazing binder and 0.1 to 50 parts by weight of a crosslinking agent per 100 parts by weight of the brazing binder.
In addition, the brazing composition of the present invention is characterized in that a brazing material for an aluminum material and the binder composition are mixed.
Further, the brazing composition of the present invention is characterized in that a flux, the binder composition, or a brazing material for aluminum is further mixed.
[0011]
The paste of the present invention is characterized in that the binder composition or any one of the above brazing compositions is mixed with an alcohol having 1 to 8 carbon atoms.
Moreover, the heat exchanger member of the present invention is characterized in that the binder composition or any one of the brazing compositions or the paste is applied to at least a part of the surface.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the (meth) acrylic acid ester (a1) represented by the general formula (1) used in the present invention, R ² Represents an alkyl group having 1 to 18 carbon atoms, preferably 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, preferably 7 to 11 carbon atoms, Examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group, methylcyclohexyl. Examples include a group, an octyl group, a dimethylcyclohexyl group, a nonyl group, a decyl group, a decalyl group, an undecyl group, a lauryl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, and an octadecyl group. Examples of the aryl group include a phenyl group, a tolyl group, a xylyl group, an ethylphenyl group, a propylphenyl group, a butylphenyl group, a naphthyl group, a pentylphenyl group, a hexylphenyl group, an octylphenyl group, and a nonylphenyl group. . Examples of the aralkyl group include a benzyl group, a methylbenzyl group, a phenylethyl group, and a naphthylmethyl group.
In the present invention, (meth) acrylic acid means one or both of acrylic acid and methacrylic acid.
In the (meth) acrylic acid ester (a1), the end of the (poly) oxyethylene chain of the ester moiety is blocked with an alkyl group, an aryl group, or an aralkyl group. There is little effect | action and generation | occurence | production of the black residue by carbide | carbonized_material generation | occurrence | production can be suppressed. And it has the characteristics that the polarity of a binder can be adjusted and the tolerance to processing oil can be provided.
Representative examples of (a1) include ethoxy polyethylene glycol monoacrylate, ethoxy polyethylene glycol monomethacrylate, methoxypolyethylene glycol monoacrylate, methoxypolyethylene glycol monomethacrylate, and the like.
[0013]
In the acid group-containing ethylenically unsaturated monomer (a2) used in the present invention, the acid group is preferably at least one selected from a carboxylic acid group, a phosphoric acid group, or a sulfonic acid group.
Examples of the carboxylic acid group-containing ethylenically unsaturated monomer include (meth) acrylic acid, vinyl acetic acid, allylic acetic acid, maleic acid, fumaric acid, itaconic acid, etc. Among them, (meth) acrylic acid is preferable. Used.
Examples of the phosphoric acid group-containing ethylenically unsaturated monomer include ethylenephosphonic acid, and examples of the sulfonic acid group-containing ethylenically unsaturated monomer include ethylenesulfonic acid. Only one type of acid group-containing ethylenically unsaturated monomer may be used, or a combination of two or more types may be used.
If the acid group of the acid group-containing ethylenically unsaturated monomer (a2) is a carboxylic acid group, it has the effect of improving the binder power of the powder wax, and if it is a phosphate group, Since it has the effect that adhesiveness improves and it has the effect that workability (bending, cutting, press work, etc.) improves if it is a sulfonic acid group, an acid group containing ethylenically unsaturated monomer (a2 The acid group is preferably at least one selected from a carboxylic acid group, a phosphoric acid group, and a sulfonic acid group.
[0014]
The (meth) acrylic acid ester-based copolymer (A) includes the components derived from the above (a1) and the components derived from the above (a2), and if necessary, these (a1), (a2) and A component derived from a copolymerizable monomer can be included.
Such monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate , (Meth) acrylic acid hexyl, (meth) acrylic acid-2-ethylhexyl, (meth) acrylic acid lauryl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid benzyl, (meth) acrylic acid decyl, (meth) acrylic Examples include (meth) acrylic acid esters such as isodecyl acid, isobornyl (meth) acrylate, acrylonitrile, styrene, and the like.
[0015]
The structural unit derived from the above (a1) in the (meth) acrylic acid ester copolymer (A) is preferably 5 to 50% by weight, more preferably 10 to 40% by weight. By making the structural unit derived from (a1) 5% by weight or more, decomposition evaporability at the time of brazing of the binder is improved and resistance to processing oil is improved, and is preferably made 50% by weight or less. This is preferable because black residue due to carbides can be reduced.
Further, the structural unit derived from the above (a2) in the (meth) acrylic acid ester copolymer (A) is contained in an amount of 0.1 to 10% by weight, more preferably 0.5 to 5% by weight. preferable. When the structural unit derived from (a2) is 0.1% by weight or more, the adhesiveness between the binder powder brazing and the aluminum base material is improved. Since it can reduce, it is preferable.
[0016]
In this invention, it is preferable that the weight average molecular weights (styrene conversion) of (meth) acrylic acid ester type copolymer (A) are 1000-100000. When the weight average molecular weight is less than 1000, the resistance to the processing oil tends to decrease. When the weight average molecular weight exceeds 100000, the processability such as peeling occurs, the brazing property decreases, and the black residue tends to increase.
In the present invention, the glass transition temperature (Tg) of the (meth) acrylic acid ester copolymer (A) is preferably higher than 0 ° C and not higher than 100 ° C. By making Tg more than 0 ° C., blocking of the heat exchanger member can be prevented. By setting Tg to 100 ° C. or less, the adhesiveness of the brazing material can be improved when the brazing material for aluminum material is applied by dipping.
[0017]
Since the binder for brazing of the present invention contains the (meth) acrylic acid ester (a1) represented by the general formula (1) and the acid group-containing ethylenically unsaturated monomer (a2) as a copolymerization component, an aluminum material When brazing an aluminum brazing material using this brazing binder, the brazing material does not fall off and comes into contact with the processing oil without deformation. It will not swell or fall off. Moreover, since it decomposes and evaporates before reaching the brazing temperature at the time of brazing, the aesthetic appearance of the heat exchanger after brazing is not impaired without inhibiting brazing.
[0018]
Next, the binder composition of the present invention will be described. The binder composition of the present invention contains the brazing binder and 0.1 to 50 parts by weight of a crosslinking agent per 100 parts by weight of the brazing binder.
The cross-linking agent has two or more functional groups that react with acid groups in the molecule. Examples of such cross-linking agents include metal chelate compounds typified by Al, Fe, and Zn, and oxazoline compounds. And epoxy compounds, among which metal chelate compounds and oxazoline compounds are preferably used. Although this crosslinking agent may use only 1 type, it can also use 2 or more types together.
By including a crosslinking agent in the binder composition of the present invention, and preferably by heating, the binder can be crosslinked after application to the surface of the member, so that there is no swelling due to processing oil or the like, and therefore the aluminum material The brazing material does not peel off after application of the brazing material.
When the amount of the crosslinking agent used is less than 0.1 parts by weight per 100 parts by weight of the brazing binder, there is no effect of adding the crosslinking agent, and the brazing filler metal is deformed during processing before brazing or is swollen by processing oil. It becomes easy to peel off. On the other hand, if it exceeds 50 parts by weight, decomposition and evaporation during brazing will be insufficient, and it will remain as a residue on the surface of the member, which may deteriorate brazing performance or damage the appearance of the heat exchanger after brazing. There is.
This binder composition is preferably a mixture of a brazing binder and a powdery crosslinking agent.
[0019]
Next, the brazing composition of the present invention will be described.
The brazing composition of the present invention comprises a mixture of an aluminum brazing material and the binder composition.
As the brazing material for the aluminum material, aluminum to be brazed or an aluminum alloy having a melting point lower than that of the aluminum alloy is used, and usually a silicon-aluminum alloy powder is used.
The ratio of the brazing material for an aluminum material and the binder composition in the brazing composition is preferably 1 to 100 parts by weight of the binder composition per 100 parts by weight of the brazing material for aluminum material. When the binder composition is less than the above lower limit, the brazing material for aluminum material is easily peeled off when the member is processed before brazing. If the amount of the binder composition exceeds the above upper limit, decomposition and evaporation at the time of brazing will be insufficient, and it will remain as a residue on the surface of the member, resulting in a decrease in brazeability or the appearance of the heat exchanger after brazing. May be damaged.
[0020]
Further, the brazing composition of the present invention may be a mixture of a flux and the binder composition.
As the flux used in the present invention, any flux used in the flux brazing method can be used. For example, sodium chloride, potassium chloride, lithium chloride, zinc chloride, lithium fluoride fluorinated aluminate A mixture of two or more selected from potassium and the like can be exemplified. The ratio of the binder composition to the flux is preferably 1 to 100 parts by weight of the binder composition per 100 parts by weight of the flux.
The brazing composition of the present invention may be a mixture of a flux, the binder composition, and a brazing material for an aluminum material.
In this case, the ratio of the flux to the brazing material for the aluminum material is the ratio normally used in the flux brazing method. The ratio of the binder composition to the aluminum brazing material is preferably 1 to 100 parts by weight of the binder composition per 100 parts by weight of the aluminum brazing material. When the binder composition is less than the above lower limit, the brazing material for an aluminum material is easily peeled off when the member is processed before brazing. If the amount of the binder composition exceeds the above upper limit, decomposition and evaporation at the time of brazing will be insufficient, and it will remain as a residue on the surface of the member, resulting in a decrease in brazeability or the appearance of the heat exchanger after brazing. May be damaged.
[0021]
The paste of the present invention is obtained by mixing the binder composition or any one of the above brazing compositions with an alcohol having 1 to 8 carbon atoms.
As this alcohol, methanol, ethanol, n-propanol, isopropanol, n-butanol, i-butanol, t-butanol, pentanol, hexanol, lauryl alcohol, octanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol Examples thereof include monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monoethyl ether and dipropylene glycol monoethyl ether.
The amount of alcohol added to the binder composition or brazing composition is preferably 10 to 1000 parts by weight of alcohol per 100 parts by weight of the binder composition or brazing composition. When an alcohol having a low flash point is used as the alcohol, it is preferable to apply the paste to a brazing member where there is no fire and volatilize the alcohol before starting the next treatment.
When such a paste is used, the wettability of the binder composition or the brazing composition with respect to the aluminum material can be improved, and uniform coating can be realized.
[0022]
The heat exchanger member of the present invention is formed by applying the binder composition or any one of the brazing compositions or the paste to at least a part of the surface.
Examples of the heat exchanger member include a heat exchanger tube and a fin member.
The heat exchanger member formed by applying the binder composition or a paste obtained by mixing alcohol to the binder composition on at least a part of the surface is coated with a brazing material for aluminum, and then pressed. Even so, there is no loss of brazing material due to deformation of the member, nor swelling or peeling due to processing oil. Further, since the binder is decomposed and evaporated at a temperature lower than the brazing temperature of the brazing material, brazing can be easily performed.
Any of the above brazing compositions or a heat exchanger member in which a paste formed by mixing alcohol with a brazing composition is applied to at least a part of the surface is deformed even if it is pressed. The brazing material does not fall off and does not swell or peel off due to processing oil, and the binder decomposes and evaporates at a temperature lower than the brazing temperature of the brazing material, so that brazing can be performed easily.
[0023]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
In Examples and Comparative Examples, the following test pieces were prepared and evaluated as follows.
[Test pieces]
An aluminum plate (3003) in which the brazing composition obtained in each Example and Comparative Example was applied and dried on one side and fixed was used.
[90-degree bending resistance]
The surface of the test piece to which the brazing material was fixed was turned outward, bent at 90 degrees with R10, and the bent portion was rubbed with a finger to investigate the presence or absence of peeling.
○: No peeling
×: With peeling
[Processing oil resistance]
After immersing the test piece in the processing oil for 1 hour, a pencil scratch test of the brazing composition fixing surface was performed to measure the pencil hardness of the coating film.
○: Pencil hardness is higher than 4B
X: Pencil hardness is 4B or less
[0024]
[Brassability] (See Fig. 1)
A spacer 2 made of a SUS304 round bar (φ1 mm, length 15 mm) is placed on the brazing composition-coated surface of the test piece 1 having a width of 25 mm, a length of 60 mm, and a thickness of 1 mm, and the width is 25 mm, the length is 55 mm, A 1 mm thick aluminum (3003) plate 3 is placed upright so that one end rests on the spacer 2 and the other end is on the test piece 1. A character-shaped gap filling test piece was assembled, brazed, and evaluation of brazing was performed with a filling length L.
○: Filling length L30mm or more
X: Filling length L less than 30 mm
[Binder residue generation status]
The test piece used for brazing evaluation was visually observed to check for the presence of black residue.
○: No residue
×: Residual
[0025]
(Example 1)
[Preparation of Binder A1 for Brazing]
1000 parts by weight of isopropyl alcohol (solvent) was placed in a reactor equipped with a stirrer, a reflux device, a dropping funnel and a nitrogen introducing tube, and the temperature was raised to 80 ° C. while stirring under a nitrogen stream.
Next, 300 parts by weight of methyl methacrylate, 450 parts by weight of n-butyl methacrylate, methoxypolyethylene glycol monomethacrylate (trade name: Bremer PME-400, manufactured by NOF Corporation, n≈9 in the general formula (1), R ¹ , R ² = Methyl, Mw≈400) 250 parts by weight, methacrylic acid 10 parts by weight, and a mixture obtained by adding an appropriate amount of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2.0 hours, and the temperature was further maintained for 1.0 hour. To complete the polymerization and obtain a solution of a brazing binder A1.
The weight average molecular weight (in terms of polystyrene) of A1 was 24,000, and Tg was 50 ° C.
[0026]
[Preparation of Binder Composition (B1) and Brazing Composition (C1)]
Binder composition B1 was obtained by mixing 20 parts by weight of an oxazolidine-based polymer solution as a crosslinking agent in terms of solid content per 100 parts by weight of solid content of the above-obtained binder A1 solution for brazing. 100 parts by weight of powder solder made of aluminum alloy BA4045 (Al-10 wt% Si) as a brazing material for aluminum material, 10 parts by weight of a fluoride-based flux mainly composed of potassium aluminum fluoride as a flux, and isopropanol as a dispersion medium Was mixed to obtain a brazing composition C1.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0027]
(Example 2)
A brazing binder A2 was obtained in the same manner as in Example 1 except that the same amount of (2-methacryloyloxyethyl) acid phosphate (manufactured by Kyoeisha Chemical Co., Ltd.) was used instead of 10 parts by weight of methacrylic acid.
The weight average molecular weight of A2 was 20,000, and Tg was 48 ° C.
A binder composition B2 and a brazing composition C2 were obtained in the same manner as in Example 1 except that the obtained binder A2 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0028]
(Example 3)
A brazing binder A3 was obtained in the same manner as in Example 1 except that the same amount of 2-acrylamido-2-methylpropanesulfonic acid (manufactured by Toagosei Co., Ltd.) was used instead of 10 parts by weight of methacrylic acid.
The weight average molecular weight of A3 was 19,000, and Tg was 49 ° C.
A binder composition B3 and a brazing composition C3 were obtained in the same manner as in Example 1 except that the obtained binder A3 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0029]
(Example 4)
As methoxypolyethyleneglycol monomethacrylate, instead of Blemmer PME-400, the same amount of Blemmer PME-100 (trade name, manufactured by NOF Corporation, n≈2, R in general formula (1), R ¹ = Methyl, R ² = H, Mw≈100). A brazing binder A4 was obtained in the same manner as in Example 1.
The weight average molecular weight of A4 was 22,000, and Tg was 47 ° C.
A binder composition B4 and a brazing composition C4 were obtained in the same manner as in Example 1 except that the obtained binder A4 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0030]
(Example 5)
By adjusting the amount of the polymerization initiator used, a brazing binder A5 having the same composition as A1 but having a weight average molecular weight of 75,000 and Tg of 55 ° C. was obtained.
A binder composition B5 and a brazing composition C5 were obtained in the same manner as in Example 1 except that the obtained binder A5 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0031]
(Example 6)
A brazing binder A6 was obtained in the same manner as in Example 1 except that 300 parts by weight of methyl methacrylate and 450 parts by weight of n-butyl methacrylate were used, and 560 parts by weight of methyl methacrylate and 190 parts by weight of n-butyl methacrylate were used.
The weight average molecular weight of A6 was 27,000, and Tg was 79 ° C.
A binder composition B6 and a brazing composition C6 were obtained in the same manner as in Example 1 except that the obtained binder A6 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0032]
(Example 7)
In place of methoxypolyethylene glycol monomethacrylate (trade name: Blemmer PME-400), the same amount of methoxypolyethylene glycol monoacrylate (trade name: Blemmer AME-400, manufactured by NOF Corporation, n≈9, R ¹ = H, R ² = Methyl, Mw≈400). A brazing binder A7 was obtained in the same manner as in Example 1.
A7 had a weight average molecular weight of 23,000 and a Tg of 49 ° C.
A binder composition B7 and a brazing composition C7 were obtained in the same manner as in Example 1 except that the obtained binder A7 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0033]
(Comparative Example 1)
Other than using the same amount of polyethylene glycol monomethacrylate (trade name: Blemmer PE-350, manufactured by NOF Corporation, n≈8, Mw≈350) instead of methoxypolyethylene glycol monomethacrylate (trade name: Blemmer PME-400) Obtained a brazing binder D1 in the same manner as in Example 1.
The weight average molecular weight of D1 was 22,000, and Tg was 53 ° C.
A binder composition E1 and a brazing composition F1 were obtained in the same manner as in Example 1 except that the obtained binder D1 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0034]
(Comparative Example 2)
A brazing binder D2 was obtained in the same manner as in Example 1 except that methoxypolyethylene glycol monomethacrylate was not used.
The weight average molecular weight of D2 was 26,000, and Tg was 49 ° C.
A binder composition E2 and a brazing composition F2 were obtained in the same manner as in Example 1 except that the obtained binder D2 was used.
A test piece was prepared using this brazing composition, tested for 90 ° bending resistance, processing oil resistance, and brazing, and the occurrence of binder residue was also observed. The results are shown in Table 1.
[0035]
[Table 1]

[0036]
As is apparent from Table 1, the brazing composition (F1) of Comparative Example 1 generates a residue on the brazing composition coating surface, and the brazing composition (F2) of Comparative Example 2 is processed with resistance to processing oil. While the binder swelled by oil immersion, all the brazing compositions obtained in the examples were excellent in brazing resistance to 90 ° bending and oil resistance, excellent brazing characteristics, and no binder residue. It can be seen that the composition is for use.
[0037]
【The invention's effect】
As is apparent from the above, when the binder of the present invention is used, good workability, oil resistance and brazing properties are obtained, and no binder residue is generated, so that the appearance of the product is not impaired. .
[Brief description of the drawings]
FIG. 1 shows a brazing composition-coated plate assembled with an inverted T-shaped gap filling test piece.
[Explanation of symbols]
1: Test piece 2: Spacer 3: Vertical plate
L: Filling length

Claims (9)

A (meth) acrylic acid ester containing a structural unit derived from the (meth) acrylic acid ester (a1) represented by the general formula (1) and a structural unit derived from the acid group-containing ethylenically unsaturated monomer (a2) A binder for brazing, comprising a copolymer (A).

[In General Formula (1), R ¹ represents hydrogen or a methyl group, R ² represents an alkyl group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, n represents an integer of 1 to 100. ) The acid group-containing ethylenically unsaturated monomer (a2) is a carboxylic acid group-containing ethylenically unsaturated monomer, a phosphoric acid group-containing ethylenically unsaturated monomer, and a sulfonic acid group-containing ethylenically unsaturated monomer. The brazing binder according to claim 1, wherein the binder is at least one selected from the group consisting of: 2. The structural unit derived from (a1) in the copolymer (A) is 5 to 50% by weight, and the structural component derived from (a2) is 0.1 to 10% by weight. Or the binder for brazing of 2 description. The weight average molecular weight of a copolymer (A) is 1,000-100,000, Glass transition temperature is over 0 degreeC, It is 100 degrees C or less, The any one of Claims 1-3 characterized by the above-mentioned. Binder for brazing. A binder composition comprising the binder for brazing according to any one of claims 1 to 4 and 0.1 to 50 parts by weight of a crosslinking agent per 100 parts by weight of the brazing binder. A brazing composition obtained by mixing a brazing material for an aluminum material and the binder composition according to claim 5. A brazing composition obtained by mixing a flux, the binder composition of claim 5, or a brazing material for aluminum. A paste comprising the binder composition according to claim 5 or the brazing composition according to claim 6 or 7 mixed with an alcohol having 1 to 8 carbon atoms. A heat exchanger member obtained by applying the binder composition according to claim 5, the brazing composition according to claim 6 or 7, or the paste according to claim 8 to at least a part of the surface.

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