JP4569721B2 - Melam methanesulfonate, process for producing the same and flame retardant polyamide resin composition using the same - Google Patents

Description

【００１４】
（ただし、Ｃは炭素原子を表し、Ｈは水素原子を表し、Ｓは硫黄原子を表し、Ｎは窒素原子を表す。そしてｘとｙとは正数を表し、０．９０≦ｙ／ｘ＜１．３の相関にある。）で表される。
【００１５】
メラムは、化学式としてＣ₆Ｈ₉Ｎ₁₁で表される（Ｎ−４，６−ジアミノ−１，３，５−トリアジン−２−イル）−１，３，５−トリアジン−２，４，６−トリアミンである。これはメラミン２分子からアンモニア１分子が脱離して縮合した１，３，５−トリアジン誘導体である。
【００１６】
さらに本発明では、ポリアミド樹脂１００重量部に対して、本発明のメタンスルホン酸メラムを１〜１００重量部、又は該メタンスルホン酸メラムを１〜１００重量部と無機充填剤を１〜３００重量部に配合してなる難燃性ポリアミド樹脂組成物を提供する。
【００１７】
【発明の実施の形態】
本発明の（ａ）工程で使用されるメラミン、メタンスルホン酸などは市販されているものを使用することができる。メタンスルホン酸はそのまま使用してもよいし、メタンスルホン酸濃度５０重量％以上の水溶液として使用してもよい。
【００１８】
本発明において、メラミンとメタンスルホン酸との混合は、メラミン粉末に、撹拌下、メタンスルホン酸又はメタンスルホン酸濃度５０重量％以上のメタンスルホン酸水溶液を添加、混合する乾式混合又は半乾式混合が効率的で好ましい。
また過剰の水の存在下でスラリー状態で混合し、反応生成物を濾過、乾燥により得ることもできる。
【００１９】
メラミンとメタンスルホン酸の混合は、乾式混合又は半乾式混合の場合、自動乳鉢、万能ミキサー、ヘンシェルミキサー、レーディゲミキサー、ホモジナイザーなどの混合・攪拌装置を用いることができる。混合反応をより均一にするためには、せん断力のあるヘンシェルミキサー又はレーディゲミキサーが好ましい。
【００２０】
本発明において、メラミンとメタンスルホン酸とを、メタンスルホン酸１モルに対してメラミンは２．０〜３．０モルの比率に混合する。メタンスルホン酸１モルに対してメラミンが２．０モル未満の比率となると、後の焼成工程で得られる焼成生成物の酸が過剰になり酸性が強くなりすぎるため好ましくない。一方、メタンスルホン酸１モルに対してメラミンが３．０モルの比率を超えると、最終焼成生成物中にメラミン残存量が多くなりすぎたり、焼成時メラミンの揮発が大きくなりすぎるため好ましくない。
【００２１】
本発明のメラミンとメタンスルホン酸の混合時、メラミンとメタンスルホン酸は反応して塩を形成することにより、顕著な発熱が認められる。
【００２２】
本発明において、メラミンとメタンスルホン酸の混合時の温度は０〜２００℃でよい。半乾式混合における水分除去の場合、水分除去を効率的に行なうためには７０〜１５０℃がよい。吸引ポンプ等で吸引しながら、減圧下で混合を行うとより効率的に水分を除去できる。混合及び攪拌の総合計時間は混合の強さにもよるが、通常１０分〜２時間でよい。
【００２３】
本発明において必要に応じて後の焼成時の固結防止や焼成機への付着防止を目的として、混合時にコロイダルシリカパウダーを加えることもできる。コロイダルシリカパウダーは、沈降性シリカパウダー、気相法シリカパウダー、水性シリカゾルの分散質であるコロイダルシルカなどが挙げられ、１次粒子径が１００ｎｍ以下のものが好ましい。そして１次粒子径としては８〜５０ｎｍのものが容易に入手できてより好ましい。コロイダルシリカパウダーの添加量は、メラミンとメタンスルホン酸の合計量１００重量部に対して１０重量部以下の比率で加えればよい。
【００２４】
本発明の（ｂ）工程において、メラミンとメタンスルホン酸との混合反応生成物を３００〜４００℃、好ましくは３２０〜３８０℃で、０．１〜３０時間、好ましくは０．５〜１０時間焼成することにより、目的とするメタンスルホン酸メラムを得ることができる。本発明で得られるメタンスルホン酸メラムは、白色又はわずかに黄色味を帯びた粉末である。
【００２５】
（ｂ）工程の焼成により、混合反応生成物中のメラミンが脱アンモニア反応してメラム化し、最終的には硫黄原子１モルに対して、０．９０〜１．３０モルの比率を有するメタンスルホン酸メラムが得られる。焼成温度が３００℃未満では混合反応生成物中のメラミンのメラム化反応が遅くなり、焼成生成物中に未反応メラミンが残存しやすくなる。４００℃を越えた場合はメタンスルホン酸メラムの分解が起こるので好ましくない。また焼成時間は、０．１時間未満では目的とするメタンスルホン酸メラムの生成が不充分であり、３０時間よりも長くてもよいが、３０時間を越えると経済的ではない。
【００２６】
本発明の（ｂ）工程の焼成は、電気炉、熱風乾燥機、ロータリーキルン、ダブルシャフト方式撹拌型焼成機、ダブルシャフト方式ニーダー型焼成機、流動焼成炉などを単独又は組み合わせて用いることができる。焼成時のメラミンの昇華による流出をある程度抑制しながらメラミンの縮合により生成するアンモニアを選択的に除去すると、メラミンのメラム化が効率的に進む。そのため、フタ付きの磁製やアルミナ製匣鉢等による焼成が好ましい。さらに均一に焼成するために撹拌できるタイプの焼成炉がより好ましく、特に、雰囲気の制御が可能なダブルシャフト方式撹拌型焼成機やロータリーキルンでは、メラミンの昇華物を系内に戻すと共に、発生するアンモニアを系外に排出しながら焼成することができて、より好ましい。また焼成は、回分式又は連続式のどちらの方法でもよい。
【００２７】
上記の焼成により目的とするメタンスルホン酸メラムが得られるが、ポリアミド樹脂の難燃剤として適用する場合に成形時のメラミン昇華を抑制するために、焼成生成物中には未反応のメラミンを極力残さないことが好ましい。またメタンスルホン酸メラム中には、焼成条件により、副反応生成物であるメラミン２分子からアンモニア２分子が脱離して縮合したメレムのメタンスルホン酸塩が数重量％含有される場合もある。
【００２８】
本発明により得られるメタンスルホン酸メラムは、水（２５℃）に対する溶解度が０．０１〜０．１０ｇ／１００ｍｌと極めて低いので、耐水性に優れる。また１０重量％水性スラリー（２５℃）として３．０〜７．０のｐＨを有することを特徴とする。さらに後の実施例１で示すように、ＴＧ／ＤＴＡ分析によれば４００℃まではほとんど分解せず、耐熱性に非常に優れることが特徴である。
【００２９】
本発明の焼成生成物であるメタンスルホン酸メラムは、必要に応じてミキサー、ピンディスクミル、ボールミル、ジェットオーマイザーなどの乾式粉砕機やカウンタージェットミル、イノマイザーなどの乾式粉砕分級機で粉砕分級することにより、好ましい平均粒子径（メジアン径）２０μｍ以下、より好ましくは平均粒子径（メジアン径）１０μｍ以下の微粉末とすることができる。
【００３０】
更に難燃剤としては、上記焼成生成物の粉砕品を使用すると共に、本発明のメタンスルホン酸メラム１００重量部に対して、シリカパウダーや無機塩基性物質などの無機物質を２５重量％以下添加し調整した粉砕品を使用することができる。その添加は室温から４００℃でよい。即ち、その添加は上記焼成終了前に加えてもよいし、焼成終了後冷却したものに加えてもよい。この添加はせん断力を有する混合装置、例えば、ヘンシェルミキサー、レーディゲミキサー、ホモジナイザー 、ホモミキサー、等を用いるのが好ましいが、Ｖ型ミキサーや万能ミキサーで混合後、ピンディスクミル、ジェットオーマイザー、ボールミル、カウンタージェットミル、イノマイザーなどの粉砕装置にかける方法でもよい。この場合も、粉砕することにより、平均粒子径２０μｍ以下、好ましくは平均粒子径１０μｍ以下の微粉末とすることができる。また、室温混合後、３００〜４００℃で再焼成してもよい。ここで上記の無機物質とは水に不溶又は溶解度の低い物質である。例えば、好ましい例として、水酸化マグネシウム、水酸化アルミニウム、水酸化カルシウム、珪酸カルシウム、珪酸マグネシウム、炭酸カルシウム、シリカパウダー、タルク、酸化亜鉛などが挙げられる。これらの無機物質は市販されているものを用いることができる。本発明の焼成生成物と上記記載の無機物質とを含む難燃剤は、水（２５℃）に対して０．０１〜０．１０ｇ／１００ｍｌの溶解度、及び１０重量％水性スラリー（２５℃）として４．０〜８．０のｐＨとすることができる。
【００３１】
次に本発明の難燃性ポリアミド樹脂組成物について説明する。本発明の難燃性ポリアミド樹脂組成物は、ポリアミド樹脂１００重量部に対して、上記のメタンスルホン酸メラムを１〜１００重量部、好ましくは３〜８０重量部に配合された物である。更に、ポリアミド樹脂１００重量部に対して、上記のメタンスルホン酸メラムを１〜１００重量部、好ましくは３〜８０重量部と、無機充填剤を１〜３００重量部とに配合されたものである。メタンスルホン酸メラムの添加量が１重量部未満では難燃効果が十分でなく、１００重量部以上配合してもそれ以上難燃効果が上がるわけではなく、かえって成形加工性が低下する。
【００３２】
本発明の難燃性ポリアミド組成物は、高度な難燃性を有し、またＵＬ−９４垂直燃焼試験時にドリップ現象を極めて起こしにくい。更に混練時の分解ガスの発生や発泡現象はほとんどなく、成形加工時の金型の汚染も解消される。
【００３３】
本発明において使用されるポリアミド樹脂としては、ε−カプロラクタム、アミノカプロン酸、エナントラクタム、７−アミノヘプタン酸、１１−アミノウンデカン酸、９−アミノノナン酸、α−ピロリドン、α−ピペリドンなどの重合体、テトラメチレンジアミン、ヘキサメチレンジアミン、ノナメチレンジアミン、ウンデカメチレンジアミン、ドデカメチレンジアミン、メタキシリレンジアミンなどのジアミンとテレフタル酸、イソフタル酸、アジピン酸、セバシン酸、ドデカン二塩基酸、グルタル酸などのジカルボン酸とを重縮合して得られる重合体又はこれらの共重合体、例えばポリアミド、４、６、７、８、１１、１２、４・６、６・６、６・９、６・１０、６・１１、６・１２、６Ｔ、９Ｔ、ＭＸＤ６などが挙げられる。これらのポリアミド樹脂は２種以上を併用してもよいし、その他の熱可塑性樹脂例えばポリオレフィン系樹脂、ポリスチレン樹脂、ＡＢＳ樹脂、ＡＳ樹脂、ポリカーボネート樹脂、ポリフェニレンエーテル樹脂、変性ポリフェニレンエーテル樹脂、ポリエステル樹脂、ポリアセタール樹脂、ポリスルホン樹脂、ポリフェニレンサルファイド樹脂、ポリイミド樹脂などを含有してもよい。
【００３４】
本発明において使用される無機充填剤としては、公知のものを使用することができる。例えばガラス繊維、炭素繊維、タルク、マイカ、シリカ、カオリン、クレー、ウオラストナイト、ガラスビーズ、ガラスフレーク、チタン酸カリウム、炭酸カルシウム、硫酸マグネシウム、酸化チタンなどが挙げられる。これらの無機充填剤の形状は、繊維状、粒状、板状、針状、球状、粉末等のいずれでもよい。
【００３５】
本発明の難燃性ポリアミド樹脂組成物においては、メタンスルホン酸メラム以外の難燃剤として、リン系難燃剤、水酸化アルミニウムや水酸化マグネシウム、シリコーン系難燃剤等の無機系難燃剤、窒素系難燃剤等の公知の難燃剤を併用することも可能である。また上記の成分以外に、熱安定剤、光安定剤、酸化防止剤、帯電防止剤、顔料、充填剤、潤滑剤、可塑剤、カップリング剤などの一般的な合成樹脂の製造の際に通常使用されるものと併用することができる。
【００３６】
また本発明のメタンスルホン酸メラムは、ポリアミド樹脂以外の樹脂、例えばフェノール樹脂、エポキシ樹脂、ポリウレタン樹脂、不飽和ポリエステル樹脂などの熱硬化性樹脂、ＰＥ，ＰＰ，ＥＶＡ，ＥＥＡなどのポリオレフィン系樹脂、ＰＳ，ＨＩＰＳ，ＡＳ，ＡＢＳ等のポリスチレン系樹脂、塩化ビニル樹脂、ポリカーボネート樹脂、ポリフェニレンエーテル樹脂、変成ポリフェニレンエーテル樹脂、ポリエステル樹脂、ポリアセタール樹脂、ポリスルホン樹脂、ポリフェニレンサルファイド樹脂、ポリイミド樹脂などの熱可塑性樹脂及びこれらのコポリマー、アロイなど幅広い樹脂の難燃剤として有用である。また、これらの樹脂成形品、樹脂含有塗料や接着剤、繊維及び繊維製品などの難燃剤として有用である。
【００３７】
更に、本発明のメタンスルホン酸メラムは難燃剤としての目的以外に、樹脂安定剤としての用途としても使用することができる。
【００３８】
なお、本発明における試料評価方法は下記の通りである。
（１）元素分析
（ｉ）炭素、窒素、水素及び硫黄
元素分析装置 ｖａｒｉｏ ＥＬ〔エレメンタール社製〕を用いて、測定した。
（２）高速液体クロマトグラフィー
試料中の塩基成分であるメラミン、メラム、メレムなどは、高速液体クロマトグラフィー装置Ｈｉｔａｃｈｉ Ｌ−４００〔（株）日立製作所製〕にて測定した。カラムは陽イオン交換樹脂系カラムを用いた。
【００３９】
（測定条件）
カラム ＰＡＴＩＳＩＬ １０−ＳＣＸ（２５０ｍｍ×４．６ｍｍφ）、
キャリヤー溶媒 ０．０５Ｍ ｐＨ３．７ リン酸緩衝液、
キャリヤー流量 １．０ｍｌ／ｍｉｎ、
オーブン温度 ４０℃、
検出方法 ＵＶ検出法（２３０ｎｍ）、
測定試料溶液調製 試料５ｍｇをオルトリン酸濃度８５重量％のオルトリン酸水溶液４９ｇに溶解後、純水にて５００ｍｌに希釈して測定試料溶液を調製する。
（３）１０重量％水性スラリー（２５℃）のｐＨ
１００ｍｌビーカーに、試料を５ｇを採取後、純水４５ｇ（２５℃）を添加した。次に、そのビーカーにマグネチック攪拌子を入れてマグネチックスターラーで１０分間攪拌して、１０重量％水性スラリーを調製した。次に、上記１０重量％水性スラリーをｐＨ計 ＨＭ−２６Ｓ〔東亜電波工業（株）製〕を用いて、測定した。
（４）水（２５℃）に対する溶解度
３００ｍｌビーカーに、試料を５．００ｇ（ａｇ）を精秤後、メスシリンダーで計量した純水２５０ｍｌ（２５℃）を添加した。次に、恒温（２５℃）下、そのビーカーにマグネチック攪拌子を入れてマグネチックスターラーで３時間攪拌して、スラリーを調製した。予め乾燥し重量を精秤したＮｏ．５Ａ濾紙にて、調整したスラリーを吸引濾過した。その際、一担濾過が終了後、濾液を別容器に採取して、その濾液でスラリーを調製したビーカー内の残存スラリーを先程濾過に使用した未溶解試料が付着しているＮｏ．５Ａ濾紙に洗い流した。よって、未溶解試料をＮｏ．５Ａ濾紙にほぼ全量を回収した。
【００４０】
次に重量を精秤したシャーレに未溶解試料を回収したＮｏ．５Ａ濾紙を入れ、予め１０５℃に加温しておいた熱風乾燥機にそのシャーレを入れて一晩乾燥した。その後、直ちにそのシャーレをデシケーターに入れて、放冷した。
【００４１】
放冷後、総重量を測定し、総重量よりＮｏ．５Ａ濾紙とシャーレの重量を差し引いて、未溶解試料量（ｂｇ）を出した。
【００４２】
溶解度（ｇ／１００ｍｌ）は １００・（ａ−ｂ）／２５０の計算式にて求めた。
（５）平均粒子径
５０％体積径（メジアン径）を平均粒子径とした。その５０％体積径（メジアン径）はレーザー回折式粒度分析計 ＰＲＯ−７０００Ｓ〔（株）セイシン企業製〕にて測定した。
【００４３】
（測定条件） 溶媒：イソプロピルアルコール（２５℃）。
（６）示差熱分析
示差熱分析装置 ＴＧ／ＤＴＡ３２０〔セイコー電子工業（株）製〕を用いて、測定した。
【００４４】
（測定条件）測定温度範囲２０〜５５０℃、昇温速度１０℃／分、空気量３００ｍｌ／分。
【００４５】
【実施例】
実施例１
（ａ）工程
ジャケットを装備した１３０Ｌのレーディゲミキサー（ステンレス製）にメラミン〔日産化学工業（株）製〕３１．０ｋｇ（２４６．０モル）を仕込み、撹拌下に濃度７０重量％のメタンスルホン酸水溶液〔東洋化成工業（株）製〕１３．５ｋｇ（メタンスルホン酸分９８．４モル）を２０分間で添加して混合した。添加終了後、ジャケットに９０℃温水を通し、真空ポンプで吸引しながら３０分間撹拌を保持し、水分を乾燥除去した。メタンスルホン酸分１モルに対してメラミンは２．５モルの比率であった。得られた白色粉末状反応生成物は４０．４ｋｇであった。
（ｂ）工程
（ａ）工程で得られた反応生成物１５ｋｇをダブルシャフト方式撹拌型焼成機に入れ、撹拌下、３４０℃で焼成を行った。昇温時間は約２時間で３４０℃となり、焼成温度３４０℃で６時間保持した。焼成によりメラミンの昇華とメラミンの縮合反応によるアンモニアの発生とが認められた。焼成生成物として１３．８ｋｇの白色粉末を得た。
【００４６】
この焼成生成物を冷却後ピンディスクミルで粉砕を行った。得られた粉砕品の平均粒子径は、４．６μｍであった。
【００４７】
この焼成生成物に関して、高速液体クロマトグラフィーの結果、メラミン／メラム／メレム＝０．８／９３．３／５．９（重量比）であった。
【００４８】
元素分析の結果は、炭素２５．９６重量％、窒素４８．７４重量％、水素３．９６重量％、硫黄８．５２重量％であった。
【００４９】
元素分析における窒素と硫黄の結果と、高速液体クロマトグラフィーにおける塩基成分のメラミンと、メラムと、メレムとの重量比より計算すると、メラム／硫黄原子＝１．１１／１．００（モル比）であった。
【００５０】
この焼成生成物は１０重量％水性スラリー（２５℃）として５．１のｐＨを有していた。また、水（２５℃）に対する溶解度は０．０４ｇ／１００ｍｌと非常に小さい値を示した。
【００５１】
この焼成生成物の示差熱分析（ＴＧ／ＤＴＡ）の結果を図１に示した。
【００５２】
実施例２
（ａ）工程
ジャケットを装備した１３０Ｌのレーディゲミキサー（ステンレス製）にメラミン〔日産化学工業（株）製〕３１．０ｋｇ（２４６．０モル）を仕込み、撹拌下に濃度７０重量％のメタンスルホン酸水溶液〔東洋化成工業（株）製〕１６．１ｋｇ（メタンスルホン酸分１１７．４モル）を２０分間で添加して混合した。
添加終了後、ジャケットに９０℃温水を通し、真空ポンプで吸引しながら３０分間撹拌を保持し、水分を乾燥除去した。メタンスルホン酸分１モルに対してメラミンは２．１モルの比率であった。得られた白色粉末状反応生成物は４２．２ｋｇであった。
（ｂ）工程
（ａ）工程で得られた反応生成物１５ｋｇをダブルシャフト方式撹拌型焼成機に入れ、撹拌下、３３０℃で焼成を行った。昇温時間は約２時間で３３０℃となり、焼成温度３３０℃で５時間保持した。焼成によりメラミンの昇華とメラミンの縮合反応によるアンモニアの発生とが認められた。焼成生成物として１３．９ｋｇの白色粉末を得た。
【００５３】
この焼成生成物を冷却後ピンディスクミルで粉砕を行った。得られた粉砕品の平均粒子径は、５．０μｍであった。
【００５４】
この焼成生成物に関して、高速液体クロマトグラフィーの結果、メラミン／メラム／メレム＝０．４／９９．１／０．５（重量比）であった。
【００５５】
元素分析の結果は、炭素２５．０７重量％、窒素４７．１６重量％、水素４．０２重量％、硫黄９．７１重量％であった。
【００５６】
元素分析における窒素と硫黄の結果と、高速液体クロマトグラフィーにおける塩基成分のメラミンと、メラムと、メレムとの重量比より計算すると、メラム／硫黄原子＝１．００／１．００（モル比）であった。
【００５７】
この焼成生成物は１０重量％水性スラリー（２５℃）として５．０のｐＨを有していた。また、水（２５℃）に対する溶解度は０．０５ｇ／１００ｍｌと非常に小さい値を示した。
【００５８】
以下の実施例及び比較例において、燃焼試験として酸素指数、ＵＬ−９４垂直燃焼試験を、押し出しペレットの発泡状態を次のようにして評価した。
（１）酸素指数
ＪＩＳ Ｋ７２０１に準拠して実施した。
（２）ＵＬ−９４垂直燃焼試験
米国アンダーライターズ・ラボラトリーズが定めたＵＬ−９４垂直燃焼試験の方法によって測定した。試験片の厚みは１／８インチとした。
（３）押し出しペレットの発泡状態
押し出しペレットの切断面の発泡状態を目視で観察し、下記の３段階で評価した。○：発泡による気泡が殆ど見られない、△：発泡による気泡が若干見られる、×：発泡による気泡が著しく見られる
実施例３、４、５
３０％ガラス繊維強化ナイロン６６（東レ（株）製：商品名ＣＭ３００１−Ｇ３０）に実施例１で製造したメタンスルホン酸メラム（ＭＭＳ−１）を表１に示す割合でミキサーで混合し、これを２軸押出機〔（株）栗本鉄工所製〕を用いてシリンダー温度２７５℃の条件下で混練してストランド状に押し出し、冷却後、切断、乾燥してペレットを得た。得られたペレットを射出成形機〔日精樹脂工業（株）製〕にて成形し、燃焼試験用の試験片を得た。これらの材料の評価結果を表１に示した。
【００５９】
実施例６、７、８
実施例１で製造したメタンスルホン酸メラム（ＭＭＳ−１）の代わりに、実施例２で製造したメタンスルホン酸メラム（ＭＭＳ−２）を使用した他は、実施例３、４、５と同様に行った。これらの材料の評価結果を表１に示した。
【００６０】
比較例１
メタンスルホン酸メラムを使用せず、３０％ガラス繊維強化ナイロン６６を直接射出成形し、燃焼試験用の試験片を得た。評価結果を表１に示した。
【００６１】
比較例２
メタンスルホン酸メラムの代わりにメラミンシアヌレート（日産化学工業（株）製：ＭＣ−６４０）を使用し、その他は実施例６と同様に行った。評価結果を表１に示した。
【００６２】
比較例３
メタンスルホン酸メラムの代わりに次に示す方法により合成したメラムを使用し、その他は実施例４と同様に行った。評価結果を表１に示した。
【００６３】
メラムは以下のように調製した。メラミン５０４ｇとパラトルエンスルホン酸一水和物３８０ｇとの均一混合粉を、２９０℃に設定した電気炉内で６時間焼成した。焼成生成物はこげ茶色を呈していた。この焼成物を３％アンモニア水溶液でパラトルエンスルホン酸を洗浄除去し、その後濾過、乾燥して３００ｇのメラムを得た。得られたメラムは高速液体クロマトグラフィーの結果、メラミン／メラム／メレム＝１．２／９８．８／０．０（重量比）であった。
【００６４】
【表１】

【００６５】
【発明の効果】
本発明により得られたメタンスルホン酸メラムは、耐熱性、耐水性に優れ、特にポリアミド樹脂用の難燃剤として極めて有用である。また、このメタンスルホン酸メラムを使用することによって、ハロゲン系難燃剤を使用することなく、合成樹脂の難燃化を達成することが可能となる。
【図面の簡単な説明】
【図１】 実施例１で得られたメタンスルホン酸メラムの示差熱分析図である。
【符号の説明】
１・・・示差熱分析（ＤＴＡ）の結果を示す曲線である。
２・・・熱重量分析（ＴＧ）の結果を示す曲線である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to melam methanesulfonate, a process for producing the same, and a flame retardant polyamide resin composition using the same. Melam methanesulfonate is suitably used as a flame retardant for synthetic resins, particularly polyamide resins.
[0002]
[Prior art]
As for the salt of melamine and sulfur-containing acid, JP-A-8-231517 discloses that an aminotriazine sulfate composition having water resistance reacts melamine and sulfuric acid in a molar ratio of 1: 0.1 to 1. A process for producing the characteristic melamine sulfate composition is described. Regarding the calcined products of sulfuric acid and melamine, the American Chemical Society Symposium Series 425 “Fire and Polymers” (ACS Symposium Series No.425 “Fire and Polymers”), Chapter 15, pages 211 to 238 [American Chemical Society] (American Chemical Society, Washington, DC, published in 1990), pyrosulfuric acid by heating melamine sulfate [melamine / sulfur atom = 1/1 (molar ratio)] at 300 to 400 ° C. It is described that dimethylam is formed.
[0003]
As a salt of 1,3,5-triazine derivative containing melam and inorganic acid, WO 98/39306 (corresponding to Japanese Patent Application Publication No. 10-306081) includes a molar ratio of melamine and phosphoric acid of 1: 2. A method for producing a melamine / melam / melem double salt polyphosphate by calcining a reaction product mixed at 0.0 to 4.0 at 340 to 450 ° C. is described. Further, in WO98 / 39307 (corresponding Japanese Patent Application Publication: JP-A-10-306082), a reaction product obtained by mixing melamine, phosphoric acid and sulfuric acid at a specific ratio is calcined at 340 to 400 ° C., The production of a melamine melam melem double salt of a polyacid consisting of phosphorus, sulfur and oxygen is disclosed.
[0004]
In WO96 / 16948 (Japanese Patent Publication No. 10-511409), as a method for producing melam which is one of melamine condensation products, a mixture of melamine and paratoluenesulfonic acid which is one of organic acids is 250 to 350. A method is described in which the melam salt of the acid is obtained by heating at 0 ° C. and purification. However, since the melam salt of paratoluenesulfonic acid obtained in the heating step of this method exhibits a strong brown color, for example, when used as an additive of a synthetic resin, it is limited in toning.
[0005]
No melamane methanesulfonate obtained by calcining a reaction product of melamine and methanesulfonic acid has been reported so far.
[0006]
In general, the flame retardancy of a polyamide resin is performed by a method of adding a halogen compound or a nitrogen compound. However, when a halogen-based compound is used, the mold may be corroded due to the generation of corrosive gas during molding, and there is also a problem that a toxic halogenated gas is generated during combustion. Accordingly, a flame retardant that does not use a halogen-based compound has attracted attention.
[0007]
As a typical non-halogen nitrogen-based flame retardant for polyamide resin, melamine cyanurate disclosed in JP-A No. 53-31759 (corresponding US Patent: US Pat. No. 4,298,518) The method of using is widely known. WO96 / 17013 (Japanese Patent Publication No. 10-509998) discloses a method of using melam as a flame retardant for a polyamide resin having a melting point of 260 ° C. or more. However, in these methods, the non-reinforced polyamide resin shows a high flame retardant effect, but it was placed under the test piece in the UL-94 vertical combustion test of the Underwriters Laboratory, which is a typical flame retardant test. Although cotton is not ignited, there is a problem that melt dripping (drip phenomenon) occurs. In recent years, there has been a tendency to increase the flame retardancy of synthetic resins, and the development of flame retardant formulations that do not melt and drip during combustion is desired. Furthermore, when these nitrogen-based flame retardants are used particularly for polyamide resins reinforced with inorganic fillers such as glass fibers, it is difficult to exhibit a sufficient flame retardant effect. In the case of a reinforced polyamide resin having a higher molding temperature, these nitrogen-based flame retardants are liable to decompose and sublimate at the time of molding, which causes problems such as foaming and mold contamination.
[0008]
[Problems to be solved by the invention]
The nitrogen-based flame retardant disclosed in the above prior art is not sufficient in the flame retardant effect, particularly in a reinforced polyamide resin, and is liable to decompose and sublimate during molding and easily cause foaming phenomenon, mold contamination, etc. It is difficult to use effectively as a flame retardant.
[0009]
The object of the present invention is to provide melam methane sulfonate and a method for producing the same, using melamine and methane sulfonic acid as raw materials, which can overcome the above-mentioned disadvantages of the prior art and can withstand a wide range of uses as a flame retardant for polyamide resin. To do. Furthermore, the present invention provides a flame retardant polyamide resin composition containing melam methanesulfonate.
[0010]
[Means for Solving the Problems]
The method for producing melam methanesulfonate of the present invention will be described.
[0011]
Solubility of 0.01 to 0.10 g / 100 ml in water (25 ° C.), pH of 3.0 to 7.0 as 10 wt% aqueous slurry (25 ° C.), and 0 to 1 mole of sulfur atom The method for producing melam methanesulfonate having a melam ratio of 90 to 1.30 mol includes the following steps (a) and (b):
(A) A step of obtaining a reaction product by mixing melamine and methanesulfonic acid at a temperature of 0 to 200 ° C. at a ratio of 2.0 to 3.0 mol with respect to 1 mol of methanesulfonic acid. ,as well as
(B) a step of firing the reaction product obtained in step (a) at a temperature of 300 to 400 ° C. for 0.1 to 30 hours;
Consists of.
[0012]
The melam methanesulfonate of the present invention has the general formula (1)
[0013]
[Chemical 1]

[0014]
(However, C represents a carbon atom, H represents a hydrogen atom, S represents a sulfur atom, N represents a nitrogen atom, and x and y represent positive numbers, 0.90 ≦ y / x < 1.3 correlation)).
[0015]
Melam has the chemical formula C ₆ H ₉ N ₁₁ (N-4,6-diamino-1,3,5-triazin-2-yl) -1,3,5-triazine-2,4,6-triamine represented by the formula: This is a 1,3,5-triazine derivative in which one molecule of ammonia is desorbed and condensed from two molecules of melamine.
[0016]
Further, in the present invention, 1 to 100 parts by weight of the methanesulfonic acid melam of the present invention or 1 to 100 parts by weight of the methanesulfonic acid melam and 1 to 300 parts by weight of the inorganic filler with respect to 100 parts by weight of the polyamide resin. A flame retardant polyamide resin composition is provided.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Commercially available melamine, methanesulfonic acid and the like used in step (a) of the present invention can be used. Methanesulfonic acid may be used as it is, or as an aqueous solution having a methanesulfonic acid concentration of 50% by weight or more.
[0018]
In the present invention, the mixing of melamine and methanesulfonic acid is performed by adding dry methanesulfonic acid or a methanesulfonic acid aqueous solution having a methanesulfonic acid concentration of 50% by weight or more to the melamine powder, and mixing them. Efficient and preferred.
It is also possible to obtain a reaction product by mixing in a slurry state in the presence of excess water and filtering and drying.
[0019]
For the mixing of melamine and methanesulfonic acid, in the case of dry mixing or semi-dry mixing, a mixing / stirring device such as an automatic mortar, universal mixer, Henschel mixer, Ladige mixer, and homogenizer can be used. In order to make the mixing reaction more uniform, a Henschel mixer or a Ladige mixer with shearing force is preferable.
[0020]
In the present invention, melamine and methanesulfonic acid are mixed in a ratio of 2.0 to 3.0 mol with respect to 1 mol of methanesulfonic acid. When the ratio of melamine is less than 2.0 moles relative to 1 mole of methanesulfonic acid, the acid of the fired product obtained in the subsequent firing step becomes excessive and the acidity becomes too strong, which is not preferable. On the other hand, if the ratio of melamine exceeds 3.0 moles with respect to 1 mole of methanesulfonic acid, the amount of melamine remaining in the final fired product becomes too large or the volatilization of melamine becomes too large at the time of firing.
[0021]
When the melamine and methanesulfonic acid of the present invention are mixed, remarkable heat generation is recognized by the reaction of melamine and methanesulfonic acid to form a salt.
[0022]
In this invention, the temperature at the time of mixing of a melamine and methanesulfonic acid may be 0-200 degreeC. In the case of removing moisture in semi-dry mixing, 70 to 150 ° C. is preferable in order to efficiently remove moisture. Moisture can be removed more efficiently by mixing under reduced pressure while sucking with a suction pump or the like. The total time for mixing and stirring is usually 10 minutes to 2 hours, although it depends on the intensity of mixing.
[0023]
In the present invention, if necessary, colloidal silica powder can be added during mixing for the purpose of preventing caking during subsequent firing and preventing adhesion to the firing machine. Examples of the colloidal silica powder include precipitated silica powder, gas phase method silica powder, colloidal silk which is a dispersoid of aqueous silica sol, and the like, and those having a primary particle diameter of 100 nm or less are preferable. A primary particle size of 8 to 50 nm is more preferable because it is easily available. What is necessary is just to add the addition amount of colloidal silica powder in the ratio of 10 weight part or less with respect to 100 weight part of total amounts of a melamine and methanesulfonic acid.
[0024]
In the step (b) of the present invention, the mixed reaction product of melamine and methanesulfonic acid is baked at 300 to 400 ° C., preferably 320 to 380 ° C., for 0.1 to 30 hours, preferably 0.5 to 10 hours. By doing so, the target melamsulfonic acid melam can be obtained. The melam methanesulfonate obtained in the present invention is a white or slightly yellowish powder.
[0025]
(B) The melamine in the mixed reaction product is deammoniated by the calcination in the step (b) to form melam, and finally methanesulfone having a ratio of 0.90 to 1.30 moles per mole of sulfur atoms. Acid melam is obtained. When the calcination temperature is less than 300 ° C., the melamation reaction of melamine in the mixed reaction product becomes slow, and unreacted melamine tends to remain in the baked product. When it exceeds 400 ° C., melam methanesulfonate is decomposed, which is not preferable. If the calcination time is less than 0.1 hour, the desired methanesulfonic acid melam is insufficiently produced and may be longer than 30 hours, but if it exceeds 30 hours, it is not economical.
[0026]
For the baking in the step (b) of the present invention, an electric furnace, a hot air dryer, a rotary kiln, a double shaft type stirring type baking machine, a double shaft type kneader type baking machine, a fluidized baking furnace, or the like can be used alone or in combination. When ammonia generated by condensation of melamine is selectively removed while suppressing the outflow due to sublimation of melamine during firing to some extent, melamization of melamine proceeds efficiently. For this reason, firing by a magnetic product with a lid or an alumina sagger is preferred. A firing furnace that can be stirred for more uniform firing is more preferable, and in particular, in a double shaft stirring-type firing machine or a rotary kiln capable of controlling the atmosphere, the sublimate of melamine is returned to the system and ammonia generated is generated. It is more preferable that it can be fired while discharging it out of the system. Further, the firing may be either a batch method or a continuous method.
[0027]
The target methanesulfonic acid melam is obtained by the above baking, but in order to suppress melamine sublimation during molding when applied as a flame retardant for polyamide resin, unreacted melamine remains as much as possible in the baking product. Preferably not. In addition, the melam methanesulfonate may contain several weight percent of melem methanesulfonate, which is obtained by desorbing and condensing 2 molecules of ammonia from 2 molecules of melamine, which is a side reaction product, depending on the firing conditions.
[0028]
The melam methanesulfonate obtained by the present invention has excellent water resistance since its solubility in water (25 ° C.) is as extremely low as 0.01 to 0.10 g / 100 ml. Moreover, it is characterized by having pH of 3.0-7.0 as 10 weight% aqueous slurry (25 degreeC). Further, as shown in Example 1 later, according to the TG / DTA analysis, it is characterized by being hardly decomposed up to 400 ° C. and extremely excellent in heat resistance.
[0029]
The methanesulfonic acid melam, which is a baked product of the present invention, is pulverized and classified by a dry pulverizer such as a mixer, a pin disc mill, a ball mill, a jet ohmizer, or a dry pulverizer such as a counter jet mill or an inomizer, as necessary. Thus, a fine powder having a preferable average particle diameter (median diameter) of 20 μm or less, more preferably an average particle diameter (median diameter) of 10 μm or less can be obtained.
[0030]
Further, as the flame retardant, the baked product pulverized product is used, and an inorganic substance such as silica powder or an inorganic basic substance is added in an amount of 25% by weight or less with respect to 100 parts by weight of melam methanesulfonate of the present invention. An adjusted pulverized product can be used. The addition may be from room temperature to 400 ° C. That is, the addition may be added before the end of the firing or may be added to the cooled product after the end of firing. For this addition, it is preferable to use a mixing device having a shearing force, such as a Henschel mixer, a Roedige mixer, a homogenizer, a homomixer, etc. Alternatively, it may be applied to a pulverizer such as a ball mill, counter jet mill or inomizer. In this case as well, fine powder having an average particle diameter of 20 μm or less, preferably an average particle diameter of 10 μm or less can be obtained by pulverization. Moreover, you may rebak at 300-400 degreeC after room temperature mixing. Here, the inorganic substance is a substance that is insoluble or has low solubility in water. For example, preferable examples include magnesium hydroxide, aluminum hydroxide, calcium hydroxide, calcium silicate, magnesium silicate, calcium carbonate, silica powder, talc, and zinc oxide. These inorganic substances can use what is marketed. The flame retardant containing the fired product of the present invention and the inorganic substance described above has a solubility of 0.01 to 0.10 g / 100 ml with respect to water (25 ° C.) and a 10 wt% aqueous slurry (25 ° C.). The pH can be 4.0 to 8.0.
[0031]
Next, the flame retardant polyamide resin composition of the present invention will be described. The flame retardant polyamide resin composition of the present invention is a compound in which 1 to 100 parts by weight, preferably 3 to 80 parts by weight of melam methanesulfonate is added to 100 parts by weight of polyamide resin. Furthermore, 1-100 parts by weight of the above methanesulfonic acid melam, preferably 3-80 parts by weight, and 1-300 parts by weight of an inorganic filler with respect to 100 parts by weight of the polyamide resin. . If the addition amount of melam methanesulfonate is less than 1 part by weight, the flame retardant effect is not sufficient, and even if it is added in an amount of 100 parts by weight or more, the flame retardant effect does not increase any more, but the moldability is rather lowered.
[0032]
The flame retardant polyamide composition of the present invention has a high level of flame retardancy, and is extremely unlikely to cause a drip phenomenon during the UL-94 vertical combustion test. Furthermore, there is almost no generation of decomposition gas or foaming phenomenon during kneading, and the contamination of the mold during molding is also eliminated.
[0033]
As the polyamide resin used in the present invention, polymers such as ε-caprolactam, aminocaproic acid, enantolactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone, Tetramethylenediamine, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, metaxylylenediamine and other diamines and terephthalic acid, isophthalic acid, adipic acid, sebacic acid, dodecanedioic acid, glutaric acid, etc. Polymers obtained by polycondensation with dicarboxylic acids or copolymers thereof, such as polyamides 4, 6, 7, 8, 11, 12, 4, 6, 6, 6, 6, 9, 6, 10, 6.11, 6.12, 6T, 9T, MXD6 and the like. These polyamide resins may be used in combination of two or more, and other thermoplastic resins such as polyolefin resins, polystyrene resins, ABS resins, AS resins, polycarbonate resins, polyphenylene ether resins, modified polyphenylene ether resins, polyester resins, You may contain polyacetal resin, polysulfone resin, polyphenylene sulfide resin, polyimide resin, etc.
[0034]
A well-known thing can be used as an inorganic filler used in this invention. For example, glass fiber, carbon fiber, talc, mica, silica, kaolin, clay, wollastonite, glass beads, glass flake, potassium titanate, calcium carbonate, magnesium sulfate, titanium oxide and the like can be mentioned. The shape of these inorganic fillers may be any of fiber, granule, plate, needle, sphere, powder and the like.
[0035]
In the flame retardant polyamide resin composition of the present invention, as a flame retardant other than melam methanesulfonate, an inorganic flame retardant such as a phosphorus flame retardant, aluminum hydroxide, magnesium hydroxide, or a silicone flame retardant, a nitrogen flame retardant It is also possible to use a known flame retardant such as a flame retardant together. In addition to the above components, it is usually used in the production of general synthetic resins such as heat stabilizers, light stabilizers, antioxidants, antistatic agents, pigments, fillers, lubricants, plasticizers, and coupling agents. Can be used in combination with those used.
[0036]
In addition, the methanesulfonic acid melam of the present invention is a resin other than a polyamide resin, for example, a thermosetting resin such as a phenol resin, an epoxy resin, a polyurethane resin, an unsaturated polyester resin, a polyolefin resin such as PE, PP, EVA, EEA, Thermoplastic resins such as polystyrene resins such as PS, HIPS, AS, ABS, vinyl chloride resins, polycarbonate resins, polyphenylene ether resins, modified polyphenylene ether resins, polyester resins, polyacetal resins, polysulfone resins, polyphenylene sulfide resins, polyimide resins, and the like It is useful as a flame retardant for a wide range of resins such as these copolymers and alloys. Moreover, it is useful as flame retardants for these resin molded products, resin-containing paints and adhesives, fibers and fiber products.
[0037]
Furthermore, melam methanesulfonate of the present invention can be used not only as a flame retardant but also as a resin stabilizer.
[0038]
In addition, the sample evaluation method in this invention is as follows.
(1) Elemental analysis
(I) carbon, nitrogen, hydrogen and sulfur
Measurement was performed using an elemental analyzer vario EL (manufactured by Elemental).
(2) High performance liquid chromatography
Melamine, melam, melem and the like, which are base components in the sample, were measured with a high performance liquid chromatography apparatus Hitachi L-400 [manufactured by Hitachi, Ltd.]. A cation exchange resin column was used as the column.
[0039]
(Measurement condition)
Column PATISIL 10-SCX (250 mm × 4.6 mmφ),
Carrier solvent 0.05M pH 3.7 phosphate buffer,
Carrier flow rate 1.0ml / min,
Oven temperature 40 ℃,
Detection method UV detection method (230 nm),
Preparation of measurement sample solution 5 mg of a sample is dissolved in 49 g of an orthophosphoric acid aqueous solution having an orthophosphoric acid concentration of 85% by weight, and then diluted to 500 ml with pure water to prepare a measurement sample solution.
(3) pH of 10 wt% aqueous slurry (25 ° C)
After collecting 5 g of a sample in a 100 ml beaker, 45 g (25 ° C.) of pure water was added. Next, a magnetic stirrer was placed in the beaker and stirred for 10 minutes with a magnetic stirrer to prepare a 10 wt% aqueous slurry. Next, the 10 wt% aqueous slurry was measured using a pH meter HM-26S [manufactured by Toa Denpa Kogyo Co., Ltd.].
(4) Solubility in water (25 ° C)
To a 300 ml beaker, 5.00 g (ag) of the sample was precisely weighed, and 250 ml (25 ° C.) of pure water weighed with a graduated cylinder was added. Next, under a constant temperature (25 ° C.), a magnetic stirrer was placed in the beaker and stirred with a magnetic stirrer for 3 hours to prepare a slurry. No. 1 was dried in advance and precisely weighed. The adjusted slurry was suction filtered with a 5A filter paper. At that time, after the one-part filtration was completed, the filtrate was collected in a separate container, and the remaining slurry in the beaker in which the slurry was prepared with the filtrate was attached to the undissolved sample previously used for filtration. Washed off on 5A filter paper. Therefore, the undissolved sample was No. Almost the entire amount was recovered on 5A filter paper.
[0040]
Next, No. 1 was obtained by collecting the undissolved sample in a petri dish with precisely weighed weight. The 5A filter paper was put, and the petri dish was put into a hot air dryer preheated to 105 ° C. and dried overnight. Thereafter, the petri dish was immediately placed in a desiccator and allowed to cool.
[0041]
After standing to cool, the total weight was measured. The undissolved sample amount (bg) was obtained by subtracting the weight of the 5A filter paper and the petri dish.
[0042]
The solubility (g / 100 ml) was determined by the calculation formula 100 · (ab) / 250.
(5) Average particle size
The 50% volume diameter (median diameter) was taken as the average particle diameter. The 50% volume diameter (median diameter) was measured with a laser diffraction particle size analyzer PRO-7000S (manufactured by Seishin Enterprise Co., Ltd.).
[0043]
(Measurement conditions) Solvent: Isopropyl alcohol (25 ° C.).
(6) Differential thermal analysis
It measured using the differential thermal analyzer TG / DTA320 [Seiko Electronics Co., Ltd. product].
[0044]
(Measurement conditions) Measurement temperature range 20-550 ° C., temperature rising rate 10 ° C./min, air volume 300 ml / min.
[0045]
【Example】
Example 1
(A) Process
Melamin [manufactured by Nissan Chemical Industries, Ltd.] 31.0 kg (246.0 mol) was charged into a 130-liter Laedige mixer (stainless steel) equipped with a jacket, and a 70 wt% aqueous methanesulfonic acid solution [ Toyo Kasei Kogyo Co., Ltd.] 13.5 kg (98.4 mol of methanesulfonic acid) was added and mixed in 20 minutes. After the addition was completed, 90 ° C. warm water was passed through the jacket, and stirring was maintained for 30 minutes while sucking with a vacuum pump to remove moisture. Melamine was 2.5 moles per mole of methanesulfonic acid. The obtained white powdery reaction product was 40.4 kg.
(B) Process
(A) 15 kg of the reaction product obtained in the step was put into a double shaft type stirring type baking machine, and baking was performed at 340 ° C. with stirring. The temperature rising time was about 340 ° C. in about 2 hours, and the firing temperature was maintained at 340 ° C. for 6 hours. It was found that calcination caused sublimation of melamine and generation of ammonia by melamine condensation reaction. As a baked product, 13.8 kg of white powder was obtained.
[0046]
The fired product was cooled and pulverized with a pin disk mill. The average particle size of the obtained pulverized product was 4.6 μm.
[0047]
With respect to this baked product, the result of high-performance liquid chromatography was melamine / melam / melem = 0.8 / 93.3 / 5.9 (weight ratio).
[0048]
The results of elemental analysis were as follows: carbon 25.96 wt%, nitrogen 48.74 wt%, hydrogen 3.96 wt%, and sulfur 8.52 wt%.
[0049]
When calculated from the results of nitrogen and sulfur in elemental analysis and the weight ratio of melamine, melam, and melem as basic components in high performance liquid chromatography, melam / sulfur atom = 1.11 / 1.00 (molar ratio). there were.
[0050]
The fired product had a pH of 5.1 as a 10 wt% aqueous slurry (25 ° C). Moreover, the solubility with respect to water (25 degreeC) showed the very small value as 0.04g / 100ml.
[0051]
The result of differential thermal analysis (TG / DTA) of this fired product is shown in FIG.
[0052]
Example 2
(A) Process
Melamin [manufactured by Nissan Chemical Industries, Ltd.] 31.0 kg (246.0 mol) was charged into a 130-liter Laedige mixer (stainless steel) equipped with a jacket, and a 70 wt% aqueous methanesulfonic acid solution [ Toyo Kasei Kogyo Co., Ltd.] 16.1 kg (methane sulfonic acid content 117.4 mol) was added over 20 minutes and mixed.
After the addition was completed, 90 ° C. warm water was passed through the jacket, and stirring was maintained for 30 minutes while sucking with a vacuum pump to remove moisture. Melamine was in a ratio of 2.1 moles per mole of methanesulfonic acid. The obtained white powdery reaction product was 42.2 kg.
(B) Process
(A) 15 kg of the reaction product obtained in the step was put into a double shaft type stirring type baking machine, and baking was performed at 330 ° C. with stirring. The temperature raising time was 330 ° C. in about 2 hours, and the temperature was kept at 330 ° C. for 5 hours. It was found that calcination caused sublimation of melamine and generation of ammonia by melamine condensation reaction. As a baked product, 13.9 kg of white powder was obtained.
[0053]
The fired product was cooled and pulverized with a pin disk mill. The average particle size of the obtained pulverized product was 5.0 μm.
[0054]
With respect to this baked product, the result of high-performance liquid chromatography was melamine / melam / melem = 0.4 / 99.1 / 0.5 (weight ratio).
[0055]
As a result of elemental analysis, carbon was 25.07% by weight, nitrogen was 47.16% by weight, hydrogen was 4.02% by weight, and sulfur was 9.71% by weight.
[0056]
Calculated from the results of nitrogen and sulfur in elemental analysis and the weight ratio of the basic components melamine, melam, and melem in high performance liquid chromatography, melam / sulfur atom = 1.00 / 1.00 (molar ratio) there were.
[0057]
The fired product had a pH of 5.0 as a 10 wt% aqueous slurry (25 ° C). Moreover, the solubility with respect to water (25 degreeC) showed the very small value as 0.05g / 100ml.
[0058]
In the following examples and comparative examples, the oxygen index and the UL-94 vertical combustion test were evaluated as the combustion test, and the foamed state of the extruded pellet was evaluated as follows.
(1) Oxygen index
This was carried out in accordance with JIS K7201.
(2) UL-94 vertical combustion test
It was measured by the UL-94 vertical combustion test method defined by US Underwriters Laboratories. The thickness of the test piece was 1/8 inch.
(3) Foamed state of extruded pellets
The foamed state of the cut surface of the extruded pellet was visually observed and evaluated in the following three stages. ○: Bubbles due to foaming are hardly seen, Δ: Some bubbles due to foaming are seen, ×: Bubbles due to foaming are noticeable
Examples 3, 4, 5
30% glass fiber reinforced nylon 66 (manufactured by Toray Industries, Inc .: trade name CM3001-G30) was mixed with methanesulfonic acid melam (MMS-1) produced in Example 1 at a ratio shown in Table 1, using a mixer. Using a twin screw extruder (manufactured by Kurimoto Iron Works Co., Ltd.), the mixture was kneaded under a cylinder temperature of 275 ° C., extruded into a strand, cooled, cut and dried to obtain pellets. The obtained pellets were molded by an injection molding machine [manufactured by Nissei Plastic Industry Co., Ltd.] to obtain a test piece for a combustion test. The evaluation results of these materials are shown in Table 1.
[0059]
Examples 6, 7, and 8
In the same manner as in Examples 3, 4, and 5 except that melam methanesulfonate (MMS-2) produced in Example 2 was used instead of melam methanesulfonate (MMS-1) produced in Example 1. went. The evaluation results of these materials are shown in Table 1.
[0060]
Comparative Example 1
Without using melam methanesulfonate, 30% glass fiber reinforced nylon 66 was directly injection molded to obtain a test piece for combustion test. The evaluation results are shown in Table 1.
[0061]
Comparative Example 2
Melamine cyanurate (manufactured by Nissan Chemical Industries, Ltd .: MC-640) was used instead of melam methanesulfonate, and the others were performed in the same manner as in Example 6. The evaluation results are shown in Table 1.
[0062]
Comparative Example 3
The melam synthesized by the following method was used instead of melam methanesulfonate, and the others were carried out in the same manner as in Example 4. The evaluation results are shown in Table 1.
[0063]
Melam was prepared as follows. A uniformly mixed powder of 504 g of melamine and 380 g of paratoluenesulfonic acid monohydrate was fired in an electric furnace set at 290 ° C. for 6 hours. The fired product had a dark brown color. The calcined product was washed with 3% aqueous ammonia to remove paratoluenesulfonic acid, then filtered and dried to obtain 300 g of melam. As a result of high performance liquid chromatography, the obtained melam was melamine / melam / melem = 1.2 / 98.8 / 0.0 (weight ratio).
[0064]
[Table 1]

[0065]
【The invention's effect】
The methanesulfonic acid melam obtained by the present invention is excellent in heat resistance and water resistance, and is extremely useful as a flame retardant for polyamide resins. Moreover, by using this melam of methanesulfonic acid, it becomes possible to achieve flame retardancy of the synthetic resin without using a halogen-based flame retardant.
[Brief description of the drawings]
1 is a differential thermal analysis diagram of melam methanesulfonate obtained in Example 1. FIG.
[Explanation of symbols]
1 is a curve showing the results of differential thermal analysis (DTA).
2 is a curve showing the results of thermogravimetric analysis (TG).

Claims (4)

Solubility of 0.01 to 0.10 g / 100 ml in water (25 ° C.), pH of 3.0 to 7.0 as 10 wt% aqueous slurry (25 ° C.), and 0 to 1 mole of sulfur atom Melam methanesulfonate having a melam ratio of 90 to 1.30 moles. The following steps (a) and (b):
(A) A step of obtaining a reaction product by mixing melamine and methanesulfonic acid in a ratio of 2.0 to 3.0 mol with respect to 1 mol of methanesulfonic acid at a temperature of 0 to 200 ° C. And (b) baking the reaction product obtained in step (a) at a temperature of 300 to 400 ° C. for 0.1 to 30 hours,
A solubility of 0.01-0.10 g / 100 ml in water (25 ° C.), a pH of 3.0-7.0 as a 10 wt% aqueous slurry (25 ° C.), and 1 mole of sulfur atoms A process for preparing melam methanesulfonate having a melam ratio of 0.90 to 1.30 moles. For 100 parts by weight of polyamide resin,
Solubility of 0.01 to 0.10 g / 100 ml in water (25 ° C.), pH of 3.0 to 7.0 as 10 wt% aqueous slurry (25 ° C.), and 0 to 1 mole of sulfur atom A flame-retardant polyamide resin composition comprising 1 to 100 parts by weight of melam methanesulfonate having a melam ratio of 90 to 1.30 mol. Furthermore, with respect to 100 parts by weight of the polyamide resin,
The flame-retardant polyamide resin composition according to claim 3, wherein 1 to 300 parts by weight of an inorganic filler is blended.

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