JP4051723B2 - Melamine polymetaphosphate and process for producing the same - Google Patents

Description

（４）粉末Ｘ線回折
Ｘ線回折装置 ＪＥＯＬ ＪＤＸ−８２００Ｔ（日本電子（株）製）を用いて、測定した。（対陰極：Ｃｕ−Ｋα）
（５）嵩比重（ゆるみ見掛け密度）
パウダーテスター（ホソカワミクロン（株）製）にて測定した。
（６）平均粒子径
５０％体積径（メジアン径）を平均粒子径とした。
【００３３】
その５０％体積径（メジアン径）は遠心沈降法粒子測定装置ＳＡ−ＣＰ３（（株）島津製作所製）にて測定した。
（測定条件） 溶媒 純水（２５℃）。
（７）１０重量％水性スラリー（２５℃）のｐＨ
３００ｍｌビーカーに、試料を２５ｇを採取後、次にメスシリンダーで計量した純水２２５ｇ（２５℃）を添加した。次に、そのビーカーにマグネチック撹拌子を入れてマグネチックスターラーで３０分間撹拌して、１０重量％水性スラリーを調製した。
【００３４】
次に、上記１０重量％水性スラリーをｐＨ計 Ｍ−８ＡＤ（（株）堀場製作所製）を用いて、測定した。
（８）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撹拌子を入れてマグネチックスターラーで３０分間撹拌して、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。
【００３５】
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８０℃に加温しておいた熱風乾燥機にそのシャーレを入れて５時間乾燥した。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。
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。
【００３６】
溶解度（ｇ／１００ｍｌ）は １００・（ａ−ｂ）／２５０の計算式にて求めた。
尚、水（３０℃）の溶解度の測定方法は、上記の純水の液温を３０℃とし、濾過操作は恒温（３０℃）下で行った以外は上記の測定方法に従った。
【００３７】
【実施例】
実施例１
（ａ）工程
５Ｌの万能ミキサー（ステンレス製）にメラミン（日産化学工業（株）製）６２０ｇ（４．９２モル）と、工業用粒状尿素（日産化学工業（株）製）１３５ｇ（２．２５モル）とを採取し、１０分間混合を行った。このメラミンと尿素との混合物に攪拌下にオルトリン酸分８５重量％のオルトリン酸水溶液（東ソー（株）製）４４３ｇ（オルトリン酸分３．８４モル）を３０分間で添加して混合した。更に添加終了後３０分間攪拌を保持した。オルトリン酸１モルに対してメラミンは１．２８モルの比率であった。このオルトリン酸水溶液の添加により顕著な発熱が起こり、水蒸気が発生した。よってウエットパウダー状生成物１１８５ｇを得た。
（ｂ）工程
（ａ）工程で得られた生成物全量１１８５ｇをステンレス製バットに入れ、電気炉にて３１０℃で焼成を行った。昇温時間は約４時間で３１０℃となり、焼成温度３１０℃を５時間保持した。尚、脱水により若干の固結が起こるため固結防止のため、昇温時被焼成物温度が１５０℃になったところで取り出し、固結状態のものを崩した上で焼成を続行した。焼成により尿素の分解とメラミンの昇華とが顕著に認められた。焼成物として７６８ｇ（理論量７９１ｇ）を得た。この焼成物を冷却後ピンディスクで粉砕を行った。
【００３８】
得られた焼成物のピンディスク粉砕品は嵩比重０．６ｇ／ｍｌ及び平均粒子径８．２μｍの粉体特性を有していた。
得られた焼成物に関して、元素分析の結果とポリメタリン酸メラミンの理論値と比較すると、炭素１７．４重量％（理論値１７．５重量％）、窒素４０．５重量％（理論値４０．８重量％）、水素５．５重量％（理論値３．４重量％）、リン１４．８重量％（理論値１５．０重量％）であった。またこの結果から焼成物中の酸素は２１．８重量％と計算され、リン原子１モルに対して２．８５モルの酸素原子の比率を有し、ポリメタリン酸のリン原子１モルに対して３．０モルの酸素原子の比率（理論値）とほぼ一致した。焼成物中の炭素原子１モルに対して２．００モルの窒素原子の比率を有し、明らかにメラミンの炭素原子１モルに対して２．０モルの窒素原子（理論値）の比率と一致した。及びリン原子１モルに対して３．０４モルの炭素原子の比率を有すことより、リン原子１モルに対して１．０１モルのメラミンの比率であった。
【００３９】
示差熱分析の結果得られた生成物は３５０℃まで重量減がほとんど認められず、非常に良好な耐熱性を示した。
焼成物は結晶性であり、粉末Ｘ線回折の結果、回折ピークにオルトリン酸メラミン、ピロリン酸メラミン、メラミンのピークは観察されなかった。
１０重量％水性スラリー（２５℃）として３．０９のｐＨを有していた。また、水（２５℃）に対する溶解度は０．０３ｇ／１００ｍｌ、そして水（３０℃）に対する溶解度は０．０４ｇ／１００ｍｌと非常に小さい値を示した。
【００４０】
また、ここでは溶解特性の評価として、測定条件を変えて溶解度を測定した。
（１）溶媒量の変更
記載された水（２５℃）に対する溶解度溶解度測定方法において、溶媒である純水２５０ｍｌ（２５℃）を純水５００ｍｌ（２５℃）に変えて、測定した。その水（２５℃）に対する溶解度は０．０２ｇ／１００ｍｌと記載方法で測定した値とほぼ同一の値を示した。
【００４１】
（２）測定試料の前処理
上記ピンディスク粉砕品２５ｇを２０００ｍｌビーカーに採取し、純水１５００ｍｌ（２５℃）を添加した後、３０分間分散させた。得られた分散液をＮｏ．５Ａの濾紙にて濾過し、未溶解物を純水６０００ｍｌ（２５℃）で洗浄後濾別した。その濾別した未溶解物を１１０℃にて乾燥した水洗浄処理試料を得た。得られた水洗浄処理試料に関して、水（２５℃）に対する溶解度は０．０３ｇ／１００ｍｌとなった。水洗浄処理前後では得られる溶解度は同一であることを確認した。
【００４２】
以上の結果から（ｂ）工程で得られた焼成物はポリメタリン酸メラミンであると判定した。得られた焼成物は純度の高いポリメタリン酸メラミンと考えられる。
比較例１
（ａ）工程において、メラミン採取量を７７４ｇ（６．１４モル）とした以外は実施例１と同様に実施した。
【００４３】
焼成物として８９２ｇ（理論量７９１ｇ）を得た。この焼成物を冷却後ピンディスクで粉砕を行った。
得られた焼成物のピンディスク粉砕品は嵩比重０．６ｇ／ｍｌ及び平均粒子径８．５μｍの粉体特性を有していた。
得られた焼成物に関して、元素分析の結果は、炭素１９．３重量％、窒素４３．５重量％、水素４．０重量％、リン１３．２重量％であった。またこの結果から焼成物中の酸素は２０．０重量％と計算され、リン原子１モルに対して２．９４モルの酸素原子の比率を有し、ポリメタリン酸のリン原子１モルに対して３．０モルの酸素原子の比率（理論値）とほぼ一致した。焼成物中の炭素原子１モルに対して１．９３モルの窒素原子の比率を有し、メラミンの炭素原子１モルに対して２．０モルの窒素原子（理論値）の比率とほぼ一致した。しかし、リン原子１モルに対して３．７８モルの炭素原子の比率を有すことより、リン原子１モルに対して１．２６モルのメラミンの比率であった。よって、得られた焼成物はポリメタリン酸メラミン及びメラミンを含有していた。
【００４４】
１０重量％水性スラリー（２５℃）として４．６３のｐＨを有していた。
比較例２
（ａ）工程において、工業用粒状尿素採取量を１１．５ｇ（０．１９モル）とした以外は実施例１と同様に実施した。
焼成物として７３４ｇ（理論量７９１ｇ）を得た。この焼成物を冷却後ピンディスクで粉砕を行った。
【００４５】
得られた焼成物のピンディスク粉砕品は嵩比重０．６ｇ／ｍｌ及び平均粒子径８．７μｍの粉体特性を有していた。
得られた焼成物に関して、元素分析の結果は、炭素１６．９重量％、窒素４０．０重量％、水素３．７重量％、リン１５．９重量％であった。またこの結果から焼成物中の酸素は２３．５重量％と計算され、リン原子１モルに対して２．８６モルの酸素原子の比率を有し、ポリメタリン酸のリン原子１モルに対して３．０モルの酸素原子の比率（理論値）とほぼ一致した。焼成物中の炭素原子１モルに対して２．０３モルの窒素原子の比率を有し、メラミンの炭素原子１モルに対して２．０モルの窒素原子の比率（理論値）とほぼ一致した。しかし、リン原子１モルに対して２．７５モルの炭素原子の比率を有すことより、リン原子１モルに対して０．９２モルのメラミンの比率であった。よって、得られた焼成物はポリメタリン酸メラミン及び遊離のポリメタリン酸を含有していた。
【００４６】
１０重量％水性スラリー（２５℃）として２．４０のｐＨを有していた。
比較例３
（ａ）工程において、工業用粒状尿素採取量を４６１ｇ（７．６８モル）とした以外は実施例１と同様に実施した。
焼成物として７１８ｇ（理論量７９１ｇ）を得た。この焼成物を冷却後ピンディスクで粉砕を行った。
【００４７】
得られた焼成物のピンディスク粉砕品は嵩比重０．６ｇ／ｍｌ及び平均粒子径８．３μの粉体特性を有していた。
得られた焼成物に関して、元素分析の結果は、炭素１６．７重量％、窒素３９．６重量％、水素３．７重量％、リン１６．３重量％であった。またこの結果から焼成物中の酸素は２３．７重量％と計算され、リン原子１モルに対して２．８２モルの酸素原子の比率を有し、ポリメタリン酸のリン原子１モルに対して３．０モルの酸素原子の比率（理論値）とほぼ一致した。焼成物中の炭素原子１モルに対して２．０３モルの窒素原子の比率を有し、メラミンの炭素原子１モルに対して２．０モルの窒素原子の比率（理論値）とほぼ一致した。しかし、リン原子１モルに対して２．６５モルの炭素原子の比率を有すことより、リン原子１モルに対して０．８８モルのメラミンの比率であった。よって、得られた焼成物はポリメタリン酸メラミン及び遊離のポリメタリン酸を含有していた。
【００４８】
１０重量％水性スラリー（２５℃）として２．２３のｐＨを有していた。
実施例２
（ａ）工程
５Ｌの万能ミキサー（ステンレス製）にメラミン（日産化学工業（株）製）５４０ｇ（４．２９モル）と、工業用粒状尿素（日産化学工業（株）製）１０８ｇ（１．８０モル）と、コロイダルシリカとして沈降性シリカパウダー（カープレックス＃８０（登録商標）、塩野義製薬（株）製、比表面積１９３ ｍ³／ｇ、シリカ分９５重量％、１次粒子径１０〜２０ｎｍ）２１ｇとを採取し、１０分間混合を行った。このメラミンと尿素とコロイダルシリカとの混合物に攪拌下にオルトリン酸分８５重量％のオルトリン酸水溶液（東ソー（株）製）４４３ｇ（オルトリン酸分３．８４モル）を３０分間で添加して混合した。更に添加終了後３０分間攪拌を保持した。オルトリン酸１モルに対してメラミンは１．１１モルの比率であった。このオルトリン酸水溶液の添加により顕著な発熱が起こり、水蒸気が発生した。よってウエットパウダー状生成物１１００ｇを得た。
【００４９】
（ｂ）工程
（ａ）工程で得られた生成物全量１１００ｇをステンレス製バットに入れ、電気炉にて３１０℃で焼成を行った。昇温時間は約４時間で３１０℃となり、焼成温度３１０℃を５時間保持した。尚、脱水により若干の固結が起こるため固結防止のため、昇温時被焼成物温度が１５０℃になったところで取り出し、固結状態のものを崩した上で焼成を続行した。焼成により尿素の分解とメラミンの昇華とが顕著に認められた。焼成物として７８０ｇ（理論量８１１ｇ）を得た。この焼成物を冷却後ピンディスクで粉砕を行った。
【００５０】
得られた焼成物のピンディスク粉砕品は嵩比重０．６ｇ／ｍｌ及び平均粒子径７．０μｍの粉体特性を有していた。
得られた焼成物に関して、元素分析の結果は、炭素１７．０重量％、窒素３９．５重量％、水素５．２重量％、リン１４．４重量％であり、そしてシリカ分の分析の結果は２．４重量％であった。またこの結果から焼成物中の酸素は２１．５重量％と計算され、リン原子１モルに対して２．８９モルの酸素原子の比率を有し、ポリメタリン酸のリン原子１モルに対して３．０モルの酸素原子の比率（理論値）とほぼ一致した。焼成物中の炭素原子１モルに対して１．９９モルの窒素原子の比率を有し、明らかにメラミンの炭素原子１モルに対して２．０モルの窒素原子の比率（理論値）と一致した。及びリン原子１モルに対して３．０５モルの炭素原子の比率を有すことより、リン原子１モルに対して１．０２モルのメラミンの比率であった。
【００５１】
示差熱分析の結果得られた生成物は３５０℃まで重量減がほとんど認められず、非常に良好な耐熱性を示した。
焼成物は結晶性である。そして、粉末Ｘ線回折の結果、回折ピークは実施例１の回折ピークと一致して、オルトリン酸メラミン、ピロリン酸メラミン、メラミンのピークは観察されなかった。
【００５２】
以上の結果から（Ｂ）工程で得られた焼成物はポリメタリン酸メラミンとコロイダルシリカとの混合物であると判定した。
得られた焼成物はポリメタリン酸メラミン９７．６重量％及びコロイダルシリカ２．４重量％を含有しており、１０重量％水性スラリー（２５℃）として３．２７のｐＨを有していた。また、水（２５℃）に対する溶解度は０．０３ｇ／１００ｍｌと非常に小さい値を示した。
【００５３】
実施例３
（ａ）工程
５Ｌの万能ミキサー（ステンレス製）にメラミン（日産化学工業（株）製）４９４ｇ（３．９２モル）と、工業用粒状尿素（日産化学工業（株）製）１４８ｇ（２．４７モル）と、沈降性シリカパウダー（カープレックス＃８０（登録商標）、塩野義製薬（株）製、シリカ分９５重量％、比表面積１９３ ｍ³／ｇ、１次粒子径１０〜２０ｎｍ）２１ｇとを採取し、１０分間混合を行った。このメラミンと尿素とコロイダルシリカとの混合物に攪拌下にオルトリン酸分８５重量％のオルトリン酸水溶液（東ソー（株）製）４４３ｇ（オルトリン酸分３．８４モル）を３０分間で添加して混合した。更に添加終了後３０分間攪拌を保持した。オルトリン酸１モルに対してメラミンは１．０２モルの比率であった。このオルトリン酸水溶液の添加により顕著な発熱が起こり、水蒸気が発生した。よってウエットパウダー状生成物１０９０ｇを得た。
【００５４】
（ｂ）工程
（ａ）工程で得られた生成物全量１０９０ｇをステンレス製バットに入れ、電気炉にて２５０℃で焼成を行った。昇温時間は約２．５時間で２５０℃となり、焼成温度２５０℃を１２時間保持した。尚、脱水により若干の固結が起こるため固結防止のため、昇温時被焼成物温度が１５０℃になったところで取り出し、固結状態のものを崩した上で焼成を続行した。焼成物として８０５ｇ（理論量８１１ｇ）を得た。
【００５５】
焼成により、ステンレス製バットへの付着及びステンレス製バットの腐食は認められなかった。
得られた焼成物に関して、元素分析の結果は、炭素１７．０重量％、窒素３９．７重量％、水素４．８重量％、リン１４．５重量％であり、そしてシリカ分の分析の結果は２．３重量％であった。またこの結果から焼成物中の酸素は２１．７重量％と計算され、リン原子１モルに対して２．９０モルの酸素原子の比率を有し、ポリメタリン酸のリン原子１モルに対して３．０モルの酸素原子の比率（理論値）とほぼ一致した。焼成物中の炭素原子１モルに対して２．００モルの窒素原子の比率を有し、明らかにメラミンの炭素原子１モルに対して２．０モルの窒素原子の比率（理論値）と一致した。及びリン原子１モルに対して３．０３モルの炭素原子の比率を有すことより、リン原子１モルに対して１．０１モルのメラミンの比率であった。
【００５６】
示差熱分析の結果得られた生成物は３５０℃まで重量減がほとんど認められず、非常に良好な耐熱性を示した。
焼成物は結晶性である。そして、粉末Ｘ線回折の結果、回折ピークは実施例１の回折ピークと一致して、オルトリン酸メラミン、ピロリン酸メラミン、メラミンのピークは観察されなかった。
【００５７】
よって、得られた焼成物はポリメタリン酸メラミン９７．７重量％及びコロイダルシリカ２．３重量％を含有していた。
実施例４
３０Ｌの撹拌機付ポリポロピレン製容器にオルトリン酸分８５重量％のオルトリン酸水溶液（東ソー（株）製）２０．０ｋｇ（オルトリン酸分１７３モル）を採取し、これに撹拌下にメラミン（日産化学工業（株）製）２．１９ｋｇ（１７．４モル）を加えた混合した後、混合液温度８０℃で２時間加熱し、メラミンを溶解したオルトリン酸水溶液２２．１９ｋｇを得た。この溶解液はオルトリン酸分７６．６重量％及びメラミン分９．８７重量％を含有し、オルトリン酸１モルに対して０．１０モルのメラミンの比率を有していた。
【００５８】
（ａ）工程
２００Ｌのジャケット付ヘンシェルミキサー（ステンレス製）にメラミン（日産化学工業（株）製）１９．６Ｋｇ（１５６モル）と、工業用粒状尿素（日産化学工業（株）製）５．０ｋｇ（８３．３モル）と、沈降性シリカパウダー（カープレックス＃８０（登録商標）、塩野義製薬（株）製、シリカ分９５重量％、比表面積１９３ ｍ³／ｇ、１次粒子径１０〜２０ｎｍ）１．１ｋｇとを採取し、５分間混合を行った。
【００５９】
このメラミンと尿素とコロイダルシリカとの混合物に攪拌下に上記メラミンを溶解したオルトリン酸水溶液１９．９ｋｇ（オルトリン酸分１５６モル、メラミン分１５．６モル）を２０分間で添加して混合した。更に添加終了後ヘンシェルミキサーのジャケットに加熱用水蒸気を通過させ加温しながら１時間撹拌を続行した。そしてドライパウダー状生成物４０．８ｋｇを得た。その生成物は、オルトリン酸１モルに対して１．１０モルのメラミンの比率の組成であった。
【００６０】
（ｂ）工程
（ａ）工程で得られた生成物をダブルシャフト方式連続焼成炉（ステンレス製）でジャケット温度３４０℃、炉内被焼成物温度２９０℃の条件で平均滞留時間が４時間になるように連続焼成を行った。連続焼成時、焼成炉には焼成物の付着も認められず、焼成終了後リン酸による焼成炉内部の腐食も認められなかった。
【００６１】
得られた焼成物は３１．８ｋｇ（理論量３３．２ｋｇ）であった。この焼成物は吸湿性が非常に少なく流動性の良好な粉体であり、ピンディスクミルにより容易に粉砕することができた。
得られた焼成物のピンディスク粉砕品は嵩比重０．６ｇ／ｍｌ及び平均粒子径８．８μｍの粉体特性を有していた。
【００６２】
得られた焼成物に関して、元素分析の結果は、炭素１７．０重量％、窒素３９．２重量％、水素４．４重量％、リン１４．５重量％であり、そしてシリカ分の分析の結果は３．１重量％であった。またこの結果から焼成物中の酸素は２１．８重量％と計算され、リン原子１モルに対して２．９１モルの酸素原子の比率を有し、ポリメタリン酸のリン原子１モルに対して３．０モルの酸素原子の比率（理論値）とほぼ一致した。焼成物中の炭素原子１モルに対して１．９８モルの窒素原子の比率を有し、明らかにメラミンの炭素原子１モルに対して２．０モルの窒素原子の比率（理論値）と一致した。及びリン原子１モルに対して３．０３モルの炭素原子の比率を有すことより、リン原子１モルに対して１．０１モルのメラミンの比率であった。
【００６３】
示差熱分析の結果得られた生成物は３５０℃まで重量減がほとんど認められず、非常に良好な耐熱性を示した。
焼成物は結晶性である。そして、粉末Ｘ線回折の結果、回折ピークは実施例１の回折ピークと一致して、オルトリン酸メラミン、ピロリン酸メラミン、メラミンのピークは観察されなかった。
【００６４】
以上の結果から（ｂ）工程で得られた焼成物はポリメタリン酸メラミンとコロイダルシリカとの混合物であると判定した。
よって、得られた焼成物はポリメタリン酸メラミン９６．９重量％及びコロイダルシリカ３．１重量％を含有していた。１０重量％水性スラリー（２５℃）として３．４５のｐＨを有していた。また、水（２５℃）に対する溶解度は０．０３ｇ／１００ｍｌと非常に小さい値を示した。
【００６５】
示差熱分析と粉末Ｘ線回折の結果を図１、図２に示す。尚、示差熱分析において１０００℃での焼成残査が１０．４重量％であるのはコロイダルシリカとリン酸の反応により生成したリン酸シリカガラス（ ＳｉＯ₂・Ｐ₂Ｏ₅）に起因するものである。
実施例５
実施例４の（ｂ）工程で得られた焼成物２３．０ｋｇに無機の塩基性物質である水酸化マグネシウム（キスマ５（登録商標）、協和化学工業（株）製）１．３８ｋｇをヘンシェルミキサー混合した後、ピンディスクミルで粉砕混合した。
【００６６】
得られた焼成物のピンディスク粉砕品は嵩比重０．６ｇ／ｍｌ及び平均粒子径１０．０μｍの粉体特性を有していた。
得られた焼成物はポリメタリン酸メラミン９１．４重量％、コロイダルシリカ２．９重量％、及び水酸化マグネシウム５．７重量％であり、１０重量％水性スラリー（２５℃）として７．３１のｐＨを有していた。また、水（２５℃）に対する溶解度は０．０２ｇ／１００ｍｌと非常に小さい値を示した。
【００６７】
示差熱分析の結果は、３５０℃まで重量減がほとんど認められず、非常に良好な耐熱性を示した。
比較例４
（ａ）工程
１０Ｌの型万能ミキサー（ステンレス製）にメラミン（日産化学工業（株）製）１０８０ｇ（オルトリン酸分８．５７モル）を採取し、これに攪拌下にオルトリン酸分８５重量％のオルトリン酸水溶液（東ソー（株）製）８８６ｇ（７．６８モル）を３０分間で添加して混合した。更に添加終了後３０分間攪拌を保持した。よってウエットパウダー状生成物１９３０ｇを得た。その生成物は、オルトリン酸１モルに対して１．１１モルのメラミンの比率の組成であった。
【００６８】
（ｂ）工程
（ａ）工程で得られた生成物９６５ｇをステンレス製バットに入れ、電気炉にて２９０℃で焼成を行った。昇温時間は約４時間で２９０℃となり、、焼成温度２９０℃を５時間保持した。尚、脱水により若干の固結が起こるため固結防止のため、昇温時被焼成物温度が１５０℃になったところで取り出し、固結状態のものを崩した上で焼成を続行した。焼成物として８０６ｇを得た。粉末Ｘ線回折の結果、ピロリン酸メラミンを主成分とし、少量のポリメタリン酸メラミンの存在が確認された。
【００６９】
比較例５
比較例４の（ａ）工程で得られた生成物９６５ｇをステンレス製バットに入れ、電気炉にて３１０℃で焼成を行った。昇温時間は約４時間で３１０℃となり、焼成温度として３１０℃を５時間保持した。尚、脱水により若干の固結が起こるため固結防止のため、昇温時被焼成物温度が１５０℃になったところで取り出し、固結状態のものを崩した上で焼成を続行した。焼成によりメラミンの昇華が顕著に認められた。得られた焼成物は７４０ｇであったが、焼成により表面は生成したポリリン酸により黒っぽくなっており、焼成物が著しくステンレス製バットに付着し、かつポリリン酸メラミンからのメラミンの脱離により生成したポリリン酸によりステンレス製バットに著しい腐食が起きていた。得られた焼成物は遊離のポリリン酸を含有しているため吸湿が大きく難燃剤として使用できるものではなかった。粉末Ｘ線回折の結果、焼成物はポリメタリン酸メラミンと判定されるが、ピークの位置にシフトが認められた。
【００７０】
得られた焼成物は、１０重量％水性スラリー（２５℃）として２．０の非常に低いｐＨを有した。そして、示差熱分析でも２８０℃からメラミンの脱離による重量減が観察され、３５０℃では４．０％の重量減を示し、耐熱性は良好ではなかった。
比較例６
実施例２に示した（ａ）工程で得られたウエットパウダー状生成物１１００ｇをステンレス製バットに入れ、電気炉にて２００℃で焼成を行った。昇温時間は約２時間で２００℃となり、焼成温度２００℃を５時間保持した。尚、脱水により若干の固結が起こるため、昇温時被焼成物温度が１５０℃になったところで取り出し、固結状態のものを崩した上で焼成を続行した。得られた焼成物は９２０ｇであった。
【００７１】
粉末Ｘ線回折の結果、生成物の回折ピークはピロリン酸メラミンの回折ピークと一致し、ポリメタリン酸メラミンの生成は認められなかった。
【００７２】
【発明の効果】
本発明の方法により得られた生成物は元素分析、粉末Ｘ線回折、示差熱分析などによりポリメタリン酸メラミン（結晶性）であることを確認した。
また、従来より知られていたポリリン酸メラミン及びポリリン酸アンモニウム・メラミン複塩とは異なり、本発明のポリメタリン酸メラミンは水（２５℃）に対して０．１０ｇ／１００ｍｌ以下の溶解度、つまり実施例に記載されているような水（２５℃）に対して０．０２〜０．０３ｇ／１００ｍｌの溶解度、及び１０重量％水性スラリー（２５℃）として２．５〜４．５のｐＨを有している。
【００７３】
本発明の製造法によれば、基本的には混合と焼成という簡単な操作により、効率よく、ポリメタリン酸メラミンを製造することができる。このポリメタリン酸メラミンは、難燃剤として、従来のリン酸メラミンと異なり、耐熱性、耐水性に優れ、かつ粉砕性、分散性、流動性など粉体特性にも優れ、更に高いリン含有量により優れた難燃性を示す。
【００７４】
本発明のポリメタリン酸メラミンはフェノール樹脂、エポキシ樹脂、ポリウレタン、不飽和ポリエステルなどの熱硬化性樹脂、ポリアミド、芳香族ポリアミド、ポリエチレンオキシド、ポリカーボネート、ポリオレフィン（ポリエチレン、ポリプロピレン、ポリスチレンなど）、ポリフェニレンエーテル、変成ポリフェニレンエーテル、ゴム変性スチレンアクリルニトリルーブタジエンースチレン（ＡＢＳ）、ポリエステル、ポリサルホン、ポリブチレンテレフタレート、塩ビ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、接着剤、繊維、繊維製品などの難燃剤として有用である。
【００７５】
本発明のポリメタリン酸メラミンはガラス繊維、カーボン繊維、チタン酸カリウムウィスカーのような強化剤、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プラスチックス物質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。また、本発明のポリメタリン酸メラミンは他のリン系難燃剤、ブロム系難燃剤などと併用することができる。
【００７６】
更に、本発明のポリメタリン酸メラミンは難燃剤以外の樹脂安定剤としても使用することができる。
【図面の簡単な説明】
【図１】 実施例４で得られたポリメタリン酸メラミンとコロイダルシリカとの混合物（ピンディスク粉砕品）の示差熱分析図である。
【図２】 実施例４で得られたポリメタリン酸メラミンとコロイダルシリカとの混合物（ピンディスク粉砕品）の粉末Ｘ線回折図である。
【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 melamine polymetaphosphate and a method for producing the same.
[0002]
[Prior art]
Regarding melamine polyphosphate, various forms of melamine polyphosphate compounds are described in the literature. For example, Japanese Examined Patent Publication No. 40-28594 discloses a method for producing a calcined melamine phosphate in which a part of the melamine orthophosphate is characterized by calcining melamine orthophosphate at 180 to 250 ° C. However, it has been pointed out that this melamine phosphate is a complex of melamine orthophosphate and melamine pyrophosphate and does not have sufficient water resistance.
[0003]
US Pat. No. 3,920,796 discloses that melamine pyrophosphate is produced by baking melamine orthophosphate at 170 to 325 ° C.
U.S. Pat. No. 4,950,757 discloses a method for producing melamine pyrophosphate, characterized by reacting pyrophosphate and melamine at 0 to 60 [deg.] C. in an aqueous medium.
[0004]
Japanese Patent Application Laid-Open No. 61-126091 discloses a condensed phosphoric acid characterized in that a condensed phosphoric acid and melamine are subjected to a solid phase reaction in the substantial absence of an aqueous medium at a temperature of spontaneously generated heat to 170 ° C. A method for producing melamine is disclosed.
It is known to employ urea as a condensing agent in the production of polyphosphates. For example, Japanese Examined Patent Publication No. 53-2170 discloses ammonium phosphate as orthophosphate, orthophosphoric acid, condensed phosphoric acid, phosphoric anhydride, urea phosphate, and mixtures thereof, and melamine, dicyancyanamide, and guanidine as nitrogen sources. Amide nitrogen obtained by carrying out a heat condensation reaction in the presence of urea, urea phosphate, and a mixture thereof, using a cyanamide derivative such as guanylurea, and a mixture thereof. A process for the production of the containing polyphosphate amide (amide polyphosphate) is disclosed. The production conditions include urea / phosphoric acid (H_ThreePO_Four) / Cyanamide derivative = 0.8 to 1.5 / 1 / 0.05 to 1 (molar ratio) in an ammonia gas atmosphere at 150 to 350 ° C. for 10 minutes to 5 hours, preferably 1 to 4 hours. It is described. In Example 1 of the publication, ammonium orthophosphate, industrial urea and melamine were mixed with urea / phosphoric acid (H_ThreePO_FourAs) / melamine = 1/1 / 0.5 (molar ratio), and a substantially water-insoluble polyphosphoric acid amide obtained by heat-condensing a raw material for firing at 240 to 260 ° C for 2.5 hours. (33.48% by weight of nitrogen, 44.73% by weight of diphosphorus pentoxide, elution rate (10% of sample was put into 100 ml of water and stirred for 1 hour at a predetermined temperature for 1 hour) 1.36%, 1 % Solution pH 8.26) is described.
[0005]
Japanese Patent Publication No. 53-15478 discloses a method for producing ammonium polyphosphate which is hardly soluble in water by calcining ammonium phosphate and urea or crystalline urea phosphate as raw materials. Production of modified ammonium polyphosphate characterized in that the raw material is heat-condensed under the condition that melamine content is 5 to 50% by weight (ratio to the total amount of raw material and melamine or melamine phosphate). A method is disclosed. In Example 1 of the same publication, ammonium phosphate, industrial urea and melamine were mixed with urea / phosphoric acid (H_ThreePO_FourAnd / or a product obtained by heat condensing the raw material mixed so as to be melamine = 1/1 / 0.5 (molar ratio) at 260 to 270 ° C for 1.5 hours in a rotary indirect heating furnace. The product was pulverized to a particle size of 32 mesh (standard sieve) and then condensed by heating at 270 ° C. for 1.5 hours in a rotary indirect heating furnace under an ammonia gas atmosphere. Ammonium polyphosphate (total nitrogen 34.52 wt%, ammonia nitrogen 8.15 wt%, diphosphorus pentoxide 44.03 wt%, elution rate (10 g of sample was put into 100 ml of water at a temperature of 25 ° C) It is described that the elution fraction after stirring for 1 hour was 0.31%, and the pH of the 1% solution was 7.60).
[0006]
Japanese Examined Patent Publication No. 55-49004 discloses a method for producing a hardly soluble ammonium polyphosphate and melamine mixture characterized by a solid-phase reaction in which a mixture of melamine phosphate and urea is heated to 240 ° C. or higher. Yes. In Example 2 of the same publication, a mixture of poorly soluble ammonium polyphosphate and melamine obtained by using 10 kg of melamine phosphate and 6 kg of urea (1.5 mol of urea with respect to 1 mol of phosphoric acid) (phosphorus 14. 5%, water solubility (10% of sample is put in 100 ml of water and the amount of elution after shaking for 30 minutes at room temperature is 4.8%).
[0007]
U.S. Pat. No. 4,043,987 discloses a process for producing ammonium polyphosphate / melamine double salt as a substituted ammonium polyphosphate. In Example 1 of the same specification, 47 g of urea was added while stirring 100 g of condensed phosphoric acid, then 8 g of melamine was added to the mixed solution, and the entire amount was calcined at 240 ° C. for 30 minutes, thereby polyphosphoric acid. It is described that a foam-like solid (a solubility of 5.4 g / 100 ml in water (25 ° C.), pH 5.68 of a 10 wt% aqueous slurry (25 ° C.)), which is an ammonium melamine double salt, was obtained. Further, the remaining foam-like solid was pulverized, and the pulverized product was pressed at a pressure of 4 × 10 using a metal pressure vessel.^FiveA pulverized product obtained by heat treatment at 170 ° C. for 13 hours under Pa (carbon 4%, nitrogen 18%, phosphorus 29%, solubility in water (25 ° C.) 3.92 g / 100 ml, 10 wt% aqueous slurry ( PH 6.63) at 25 ° C) is described.
[0008]
On the other hand, the use of melamine polyphosphate as a flame retardant has been known for a long time, and many proposals have been made so far. For example, Japanese Patent Laid-Open No. 53-49054 discloses a polyamide resin composition having improved flame retardancy, which comprises adding an inorganic filler and melamine phosphate to polyamide.
In JP-A-61-126091, condensed melamine phosphate is effective as a flame retardant for thermoplastic resins such as polyester, polyamide and polyolefin, thermosetting resins such as phenol and urethane epoxy, and cellulose materials. Are listed.
[0009]
Further, JP-A-7-316415 discloses a flame-retardant polyphenylene ether resin composition characterized by adding melamine phosphate to a polyphenylene ether resin composition.
[0010]
[Problems to be solved by the invention]
All of the melamine orthophosphate, melamine pyrophosphate, and calcined melamine disclosed in the above prior art have a high water content and do not have sufficient heat stability, and before reaching a heating temperature of 300 ° C. In addition, there are a drawback that water and melamine are remarkably eliminated and a high water-soluble component content. In addition, the above-mentioned condensed melamine phosphate is improved with little water and ammonia desorption by heating to a temperature of 300 ° C., but has a drawback of high water-soluble component content. Therefore, these melamine orthophosphates and melamine polyphosphates are effective as flame retardants for resins and cellulose materials having a low molding temperature, but the molding temperature is such that the resin temperature is 300 ° C. even temporarily. It is difficult to use effectively as a high resin flame retardant.
[0011]
In addition, the above-mentioned polyphosphate amide prepared by adopting urea as a condensing agent, a mixture of ammonium polyphosphate and melamine, ammonium polyphosphate / melamine double salt, etc. can be desorbed by heating to 300 ° C. Although improved a little, thermal decomposition and desorption of ammonia occurs. And most have the fault that water-soluble component content is high. Therefore, they are effective as flame retardants for resins with low molding temperatures and cellulose materials, but are effective as flame retardants for resins with high molding temperatures such that the resin temperature is 300 ° C even if temporarily. It is difficult to use.
[0012]
The present invention provides a melamine polymetaphosphate capable of withstanding a wide range of uses as a flame retardant, and a method for producing the same, by solving the above-mentioned drawbacks of the prior art.
[0013]
[Means for Solving the Problems]
The method for producing melamine polymetaphosphate of the present invention includes the following steps (a) and (b):
(A) Melamine, urea, and an orthophosphoric acid aqueous solution containing 40% by weight or more of orthophosphoric acid in a ratio of 1.0 to 1.5 moles of melamine per mole of orthophosphoric acid, and orthophosphoric acid 1 Urea is mixed in a molar ratio of 0.1 to 1.5 at a temperature of 0 to 140 ° C. to form a reaction mixture, and the reaction mixture is subjected to moisture at a temperature of 0 to 140 ° C. A step of obtaining a powdery product consisting of a double salt of orthophosphoric acid, melamine and urea by stirring while removing
(B) It consists of the process of obtaining the melamine polymetaphosphate by baking the powdery product obtained at the process (a) for 0.1 to 30 hours at the temperature of 240-340 degreeC, preventing caking. .
[0014]
  And as an improvement method of the manufacturing method of the melamine polymetaphosphate of this invention, in implementation of the said (a) and (b) process,In the step (a), colloidal silica is added in a ratio of 16 parts by weight or less with respect to 100 parts by weight of melamine,Colloidal silica is contained in the powdered product.
[0015]
In the melamine polymetaphosphate of the present invention, the degree of polymerization (n) of the melamine salt of chain phosphate increases, and the formula (1)
(MHP0_Three)_n .... (1)
(However, M represents melamine, H represents a hydrogen atom, P represents a phosphorus atom, O represents an oxygen atom, and n represents an integer.) Melamine of a long-chain polyphosphate represented by Salt.
[0016]
Where melamine has the formula (2)
C_ThreeN₆H₆   (2)
It is represented by
Regarding the solubility of the melamine polymetaphosphate of the present invention, it has a solubility of 0.01 to 0.10 g / 100 ml with respect to water (25 ° C.). In the analysis of the same sample, almost the same value can be obtained as the solubility even if the solute and solvent ratio are changed as the dissolution condition. Furthermore, even if the sample is carefully washed with water and dried, and the solubility is measured, the same value as before the treatment can be obtained. On the other hand, conventionally known melamine polyphosphate and ammonium melamine polyphosphate double salt have 0% of water (25 ° C.) due to the high solubility of the compound or the large amount of water-soluble components contained. Most have solubility characteristics exceeding the value of 10 g / 100 ml.
[0017]
The 10 wt% aqueous slurry (25 ° C) of the melamine polymetaphosphate of the present invention has a pH of 2.5-4.5. On the other hand, it is described that a conventionally known solution of ammonium polyphosphate / melamine double salt has a pH of 5.0 to 9.0.
In the composition of melamine polymetaphosphate of the present invention, it has a ratio of oxygen atom of approximately 3.0 mol per mol of phosphorus atom, and a ratio of nitrogen atom of approximately 2.0 mol per mol of carbon atom. And having a ratio of 3.0 to 3.3 moles of carbon atoms to 1 mole of phosphorus atoms, and a ratio of 1.0 to 1.1 moles of melamine to 1 mole of phosphorus atoms. . Focusing on nitrogen atoms, it has a ratio of 6.0 to 6.6 nitrogen atoms per mole of phosphorus atoms. On the other hand, it has been described that melamine polyphosphate and ammonium polyphosphate / melamine double salt which are conventionally known have a nitrogen atom ratio of 1.4 to 4.5 mol per mol of phosphorus atom. .
[0018]
From the result of differential thermal analysis, the melamine polymetaphosphate of the present invention shows very good heat resistance with no weight loss observed up to 350 ° C. From the results of powder X-ray diffraction, the melamine polymetaphosphate of the present invention is a crystalline substance. In the diffraction peak, melamine orthophosphate, melamine pyrophosphate and melamine are not observed.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
The melamine, urea, and orthophosphoric acid aqueous solution used for this invention can use what is marketed.
As the orthophosphoric acid aqueous solution, both of the dry method and the wet method can be used with an orthophosphoric acid concentration of 40% by weight or more, but the concentration is preferably as high as possible. An aqueous orthophosphoric acid solution is particularly preferred. An orthophosphoric acid aqueous solution having a concentration of less than 40% by weight is not preferable because water is excessive in the step (a) and it takes too much time to dry after the mixing reaction.
[0020]
Urea can be either granular urea or powdered urea.
In the present invention, a mixing / stirring device such as an automatic mortar, a universal mixer, a Henschel mixer, or a homogenizer can be used in the reaction in the step (a).
In the step (a), remarkable heat generation occurs by mixing melamine, urea, and an orthophosphoric acid aqueous solution. For this reason, when the orthophosphoric acid solution used has a high concentration of orthophosphoric acid, the water contained in the orthophosphoric acid aqueous solution evaporates, and the product is obtained as a wet or dry powder. On the other hand, when the concentration of orthophosphoric acid is low, heating is performed during mixing and stirring of the mixture, and the target wet or dry powder product is obtained by increasing the amount of water evaporation. The mixing / stirring device is preferably a Henschel mixer having shearing force in order to make the reaction uniform.
[0021]
In the step (a) of the present invention, the ratio of melamine is 1.0 to 1.5 moles per mole of orthophosphoric acid, and the ratio of urea is 0.1 to 1.5 moles per mole of orthophosphoric acid. Is preferred.
In the present invention, the mixing ratio of melamine and orthophosphoric acid may basically be a ratio of 1.0 mole of melamine per mole of orthophosphoric acid, but melamine is reduced by sublimation in step (b). ) In the step, it is preferable to make melamine excess in advance. Melamine may exceed the ratio of 1.5 moles per mole of orthophosphoric acid, but exceeding 1.5 moles is not preferable because the sublimation of melamine increases and the environment is deteriorated. The ratio of melamine is particularly preferably from 1.02 to 1.30 moles per mole of orthophosphoric acid. In step (a), melamine is added to an orthophosphoric acid aqueous solution in advance at a ratio of 0.15 mol or less, preferably 0.05 to 0.15 melamine to 1 mol of orthophosphoric acid. By using it, the reaction can be made more uniform and a uniform product can be obtained. In the present invention, urea promotes dehydration condensation of orthophosphoric acid in step (b) and plays an important role in the production of melamine polymetaphosphate. When the ratio of urea is less than 0.1 mol with respect to 1 mol of orthophosphoric acid, this effect is reduced and melamine is decomposed. On the other hand, when the ratio exceeds 1.5 mol, excess urea remains, and ammonia gas is generated in the step (b), which is not preferable because it promotes sublimation of melamine. In order to prevent decomposition of melamine and excessive urea, 0.3 to 0.7 is more preferable.
[0022]
In the step (a) of the present invention, the temperature during mixing and stirring of melamine, urea, and aqueous orthophosphoric acid may be 0 to 140 ° C., but preferably 80 to 110 ° C. in order to efficiently remove moisture. Good. The total time for mixing and stirring is usually 10 minutes to 2 hours, although it depends on the intensity of mixing. Moreover, since mixing of melamine, urea, and orthophosphoric acid aqueous solution is an exothermic reaction, it is preferable to mix melamine and urea in advance and then add and mix the orthophosphoric acid aqueous solution over time.
[0023]
In the step (a) of the present invention, orthophosphoric acid and melamine and urea react by mixing to form a double salt as a compound of orthophosphoric acid, melamine and urea. Although the composition is not specified, the total molar amount of melamine and urea is in a molar ratio of 1.1 to 1 mole of orthophosphoric acid, and melamine has a ratio of 1 mole to 2 moles to 1 mole of orthophosphoric acid. The compound having a ratio of 1 mole and 3 moles of urea with respect to 1 mole of orthophosphoric acid exists, and the double salt has a total mole amount of melamine and urea of 1 mole with respect to 1 mole of orthophosphoric acid. It is estimated that it has the above ratio. The product obtained in the step (a) is a wet powder product or a dry powder product composed of a mixture of this double salt and excess urea.
[0024]
In the step (a) of the present invention, colloidal silica is previously added in the step (a), and the colloidal silica is 16 parts by weight or less with respect to 100 parts by weight of the melamine content of the powdery product obtained in the step (a). In this ratio, colloidal silica can be contained in the powder product. (A) Considering the use as a flame retardant, the amount of colloidal silica added in step (a) has no flame retardant effect per se, so the ratio of colloidal silica to 16 parts by weight or less with respect to 100 parts by weight of melamine In addition, it is necessary to prevent a decrease in the flame retardant effect. A preferable addition ratio of colloidal silica is a ratio of 0.5 to 10 parts by weight of colloidal silica with respect to 100 parts by weight of melamine. In the step (a), the addition of colloidal silica can promote the formation of a double salt more uniformly in the mixed stirring of melamine, urea, and orthophosphoric acid. Colloidal silica is an inert substance in this double salt reaction.
[0025]
In step (b) of the present invention, melamine polymetaphosphate can be produced by firing the product obtained in step (a) at a firing temperature of 240 to 340 ° C. for 0.1 to 30 hours. In step (b) of the present invention, melamine polymetaphosphate is produced at a low temperature such as 240 ° C. where melamine pyrophosphate is usually produced, although surprisingly via melamine pyrophosphate. This is because urea is decomposed and eliminated from the orthophosphoric acid, melamine and urea double salt obtained in step (a) by firing, and polymetaphosphoric acid produced due to the dehydration condensation promoting effect of urea is strongly recombined with melamine. It is estimated that melamine acid was generated. If it is less than 240 ° C., melamine polymetaphosphate cannot be obtained, and if it exceeds 340 ° C., melamine desorption from melamine polymetaphosphate is increased, which is not preferable. In particular, a temperature of 260 to 320 ° C. is preferable because elimination of melamine is suppressed.
[0026]
If the calcination time in step (b) of the present invention is less than 0.1 hour, the production of melamine polyphosphate is insufficient and may be longer than 30 hours, but if it exceeds 30 hours, it is not economical.
For the baking in the step (b) of the present invention, an electric furnace, a hot air dryer, a rotary kiln, a double shaft continuous baking furnace, a fluidized baking furnace, or the like can be used alone or in combination. In the step (b), a type of baking furnace that can be stirred at the time of baking is preferable since solidification of the powder occurs due to dehydration and gas is generated due to decomposition of urea, sublimation of melamine, and the like. As a preferable firing furnace, a double shaft type continuous firing furnace can be exemplified. Furthermore, it is more preferable to fire in a fluidized firing furnace after firing in a double shaft type continuous firing furnace.
[0027]
Colloidal silica is amorphous silica in which primary particles have a colloidal dimension. In the step (b) of the present invention, containing colloidal silica in the powdery product prevents adhesion of melamine polymetaphosphate to the baking apparatus during baking and also suppresses corrosion. In addition, there is an effect of improving powder characteristics such as dispersibility and fluidity of melamine polymetaphosphate. Examples of colloidal silica include precipitated silica powder, gas phase method silica powder, colloidal silica 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. Even if colloidal silica is not added in advance in the step (a), the colloidal silica can be added to the powder product by adding the colloidal silica in the step (b). The amount of colloidal silica added in the step (b) has no flame retardant effect in view of the use as a flame retardant, so the melamine content of the powdery product obtained in the step (a) is 100. It is necessary to add colloidal silica to the ratio of 16 parts by weight or less with respect to parts by weight to prevent a reduction in flame retardant effect. And the addition ratio of a preferable colloidal silica is a ratio of 0.5-10 weight part of colloidal silica with respect to 100 weight part of melamine contents of the powdery product obtained at the step (a).
[0028]
These calcined products are subjected to dry pulverization with a mixer, a pin disc mill, a ball mill, a jet ohmizer or the like, if necessary, so that the average particle diameter (median diameter) is preferably 20 μm or less, more preferably an average particle diameter ( The median diameter can be a fine powder of 10 μm or less.
Furthermore, as a flame retardant, using the pulverized product of the fired product obtained in step (b) of the present invention, 100 parts by weight of the fired product obtained in step (b) of the present invention, A pulverized product prepared by adding 25 parts by weight or less of an inorganic and / or organic basic substance can be used. The addition may be from room temperature to 340 ° C. That is, the addition may be added before the end of firing in step (b) 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 homogenizer, or a homomixer. You can also use the method. In this case as well, fine powder having an average particle size of 20 μm or less, preferably an average particle size of 10 μm can be obtained by pulverization. Further, after mixing at room temperature, it may be refired at 240 to 340 ° C.
[0029]
Here, the inorganic and / or organic basic substance is a substance that has basicity capable of reacting with phosphoric acid and is insoluble or low in solubility in water. For example, as preferable examples, inorganic substances such as magnesium hydroxide, aluminum hydroxide, calcium hydroxide, calcium silicate, magnesium silicate, calcium carbonate, zinc oxide, melamine, N-alkyl melamine and other melamine derivatives, melem, melon, Organic substances such as melamine resin, amide resin, amino-based silane coupling agent, phenol resin, and amines can be used. As these inorganic and / or organic basic substances, commercially available ones can be used.
[0030]
The baked product obtained in the step (b) of the present invention is basically acidic with melamine polymetaphosphate, but the mixture containing an inorganic and / or organic basic substance is neutralized by the basic substance. From weakly acidic to weakly alkaline, it exhibits a pH of 5-9. In addition, the sample evaluation method in this invention is as follows. Here, a pin disc pulverized product was adopted as a sample.
(1) Elemental analysis
(I) carbon, nitrogen, and hydrogen
Measurement was performed using an elemental analyzer 2400CHN Elemental Analyzer (Perkin Elmer).
[0031]
(Ii) phosphorus
It was measured by phosphovanadomolybdic acid spectrophotometry.
(2) Silica (silicon oxide: SiO₂) Minute analysis
Measurement was performed using a fluorescent X-ray analyzer SEA2001L (manufactured by Seiko Denshi Kogyo Co., Ltd.).
(3) Differential thermal analysis
It measured using the differential thermal analyzer TG / DTA320U (Seiko Electronics Co., Ltd. product).
[0032]

(4) Powder X-ray diffraction
Measurement was performed using an X-ray diffraction apparatus JEOL JDX-8200T (manufactured by JEOL Ltd.). (Counter cathode: Cu-Kα)
(5) Bulk specific gravity (loose apparent density)
Measurement was performed with a powder tester (manufactured by Hosokawa Micron Corporation).
(6) Average particle size
The 50% volume diameter (median diameter) was taken as the average particle diameter.
[0033]
The 50% volume diameter (median diameter) was measured with a centrifugal sedimentation particle measuring apparatus SA-CP3 (manufactured by Shimadzu Corporation).
(Measurement conditions) Solvent Pure water (25 ° C.).
(7) pH of 10 wt% aqueous slurry (25 ° C)
After collecting 25 g of a sample into a 300 ml beaker, 225 g (25 ° C.) of pure water weighed with a graduated cylinder was added. Next, a magnetic stirrer was placed in the beaker and stirred with a magnetic stirrer for 30 minutes to prepare a 10 wt% aqueous slurry.
[0034]
Next, the 10 wt% aqueous slurry was measured using a pH meter M-8AD (manufactured by Horiba, Ltd.).
(8) Solubility in water (25 ° C)
To a 300 ml beaker, 5.00 g (ag) of the sample was precisely weighed, and 250 ml of pure water (25 ° C.) weighed with a graduated cylinder was added. Next, under a constant temperature (25 ° C.), a magnetic stirrer was placed in the beaker and stirred for 30 minutes with a magnetic stirrer 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.
[0035]
Next, No. 1 was obtained by collecting the undissolved sample in a petri dish with precisely weighed weight. 5A filter paper was put, and the petri dish was put in a hot air dryer preheated to 80 ° C. and dried for 5 hours. Thereafter, the petri dish was immediately placed in a desiccator and allowed to cool.
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.
[0036]
The solubility (g / 100 ml) was determined by the calculation formula 100 · (ab) / 250.
In addition, the measuring method of the solubility of water (30 degreeC) followed the said measuring method except having performed the liquid temperature of said pure water 30 degreeC, and performing filtration operation under constant temperature (30 degreeC).
[0037]
【Example】
Example 1
(A) Process
Melamine (Nissan Chemical Co., Ltd.) 620 g (4.92 mol) and industrial granular urea (Nissan Chemical Industry Co., Ltd.) 135 g (2.25 mol) in a 5 L universal mixer (made of stainless steel) Collected and mixed for 10 minutes. To this mixture of melamine and urea, 443 g (orthophosphoric acid content 3.84 mol) of an orthophosphoric acid aqueous solution (manufactured by Tosoh Corporation) having an orthophosphoric acid content of 85% by weight was added and mixed for 30 minutes. Further, stirring was maintained for 30 minutes after the end of the addition. The ratio of melamine was 1.28 moles per mole of orthophosphoric acid. The addition of this orthophosphoric acid aqueous solution caused a significant exotherm, and water vapor was generated. Thus, 1185 g of a wet powder product was obtained.
(B) Process
A total of 1185 g of the product obtained in the step (a) was put in a stainless steel bat and fired at 310 ° C. in an electric furnace. The temperature raising time was 310 ° C. in about 4 hours, and the firing temperature of 310 ° C. was maintained for 5 hours. Since some solidification occurs due to dehydration, in order to prevent solidification, the material to be fired at the time of temperature rise was taken out when the temperature reached 150 ° C., and the solidified material was broken to continue the firing. The decomposition of urea and the sublimation of melamine were remarkably recognized by firing. As a fired product, 768 g (theoretical amount 791 g) was obtained. The fired product was cooled and pulverized with a pin disk.
[0038]
The obtained pin disc pulverized product of the fired product had powder characteristics with a bulk specific gravity of 0.6 g / ml and an average particle size of 8.2 μm.
The obtained fired product was compared with the result of elemental analysis and the theoretical value of melamine polymetaphosphate, 17.4% by weight of carbon (theoretical value 17.5% by weight), 40.5% by weight of nitrogen (theoretical value 40.8). % Of hydrogen), 5.5% by weight of hydrogen (theoretical value 3.4% by weight), and 14.8% by weight of phosphorus (theoretical value 15.0% by weight). Further, from this result, oxygen in the fired product was calculated to be 21.8% by weight, and had a ratio of 2.85 mol oxygen atom to 1 mol phosphorus atom, and 3 oxygen to 1 mol phosphorus atom of polymetaphosphoric acid. It almost coincided with the ratio (theoretical value) of 0.0 mol oxygen atom. It has a ratio of nitrogen atom of 2.00 mol to 1 mol of carbon atom in the fired product, and clearly agrees with the ratio of 2.0 mol of nitrogen atom (theoretical value) to 1 mol of carbon atom of melamine did. And it was a ratio of 1.01 mol of melamine to 1 mol of phosphorus atoms because it had a ratio of 3.04 mol of carbon atoms to 1 mol of phosphorus atoms.
[0039]
The product obtained as a result of the differential thermal analysis showed almost no weight loss up to 350 ° C. and showed very good heat resistance.
The fired product was crystalline, and as a result of powder X-ray diffraction, the peaks of melamine orthophosphate, melamine pyrophosphate, and melamine were not observed in the diffraction peaks.
It had a pH of 3.09 as a 10 wt% aqueous slurry (25 ° C). Further, the solubility in water (25 ° C.) was 0.03 g / 100 ml, and the solubility in water (30 ° C.) was 0.04 g / 100 ml.
[0040]
Here, as an evaluation of the dissolution characteristics, the solubility was measured by changing the measurement conditions.
(1) Changing the amount of solvent
In the solubility solubility measurement method for water (25 ° C.) described, the measurement was performed by changing 250 ml (25 ° C.) of pure water as a solvent to 500 ml (25 ° C.) of pure water. Its solubility in water (25 ° C.) was 0.02 g / 100 ml, which was almost the same as the value measured by the described method.
[0041]
(2) Pretreatment of measurement sample
25 g of the above pin disk pulverized product was collected in a 2000 ml beaker, and after adding 1500 ml of pure water (25 ° C.), it was dispersed for 30 minutes. The resulting dispersion was designated as No. The mixture was filtered through 5A filter paper, and the undissolved material was washed with 6000 ml of pure water (25 ° C.) and then filtered off. A water-washed sample obtained by drying the undissolved material separated by filtration at 110 ° C. was obtained. With respect to the obtained water-washed sample, the solubility in water (25 ° C.) was 0.03 g / 100 ml. It was confirmed that the solubility obtained before and after the water washing treatment was the same.
[0042]
From the above results, it was determined that the fired product obtained in step (b) was melamine polymetaphosphate. The obtained fired product is considered to be highly pure melamine polymetaphosphate.
Comparative Example 1
(A) In the process, it implemented similarly to Example 1 except the melamine collection amount having been 774g (6.14 mol).
[0043]
892 g (theoretical amount 791 g) was obtained as a fired product. The fired product was cooled and pulverized with a pin disk.
The obtained pin disc pulverized product of the fired product had powder characteristics with a bulk specific gravity of 0.6 g / ml and an average particle size of 8.5 μm.
With respect to the obtained fired product, the results of elemental analysis were as follows: carbon 19.3% by weight, nitrogen 43.5% by weight, hydrogen 4.0% by weight, and phosphorus 13.2% by weight. Further, from this result, oxygen in the fired product was calculated to be 20.0% by weight, and had a ratio of 2.94 mol of oxygen atoms to 1 mol of phosphorus atoms, and 3% to 1 mol of phosphorus atoms of polymetaphosphoric acid. It almost coincided with the ratio (theoretical value) of 0.0 mol oxygen atom. It has a ratio of 1.93 moles of nitrogen atoms to 1 mole of carbon atoms in the fired product, and almost coincides with the ratio of 2.0 moles of nitrogen atoms (theoretical value) to 1 mole of carbon atoms in melamine. . However, since it had a ratio of 3.78 moles of carbon atoms to 1 mole of phosphorus atoms, it was a ratio of 1.26 moles of melamine to 1 mole of phosphorus atoms. Therefore, the fired product obtained contained melamine polymetaphosphate and melamine.
[0044]
It had a pH of 4.63 as a 10 wt% aqueous slurry (25 ° C).
Comparative Example 2
In the step (a), the same procedure as in Example 1 was conducted except that the amount of industrial granular urea collected was 11.5 g (0.19 mol).
As a fired product, 734 g (theoretical amount: 791 g) was obtained. The fired product was cooled and pulverized with a pin disk.
[0045]
The obtained pin disc pulverized product of the fired product had powder characteristics with a bulk specific gravity of 0.6 g / ml and an average particle size of 8.7 μm.
With respect to the obtained fired product, the results of elemental analysis were as follows: carbon 16.9% by weight, nitrogen 40.0% by weight, hydrogen 3.7% by weight, and phosphorus 15.9% by weight. From this result, the oxygen in the fired product was calculated to be 23.5% by weight, and had a ratio of 2.86 moles of oxygen atom to 1 mole of phosphorus atom, and 3% to 1 mole of phosphorus atom of polymetaphosphoric acid. It almost coincided with the ratio (theoretical value) of 0.0 mol oxygen atom. It has a ratio of 2.03 moles of nitrogen atoms to 1 mole of carbon atoms in the fired product, and almost coincides with the ratio (theoretical value) of 2.0 moles of nitrogen atoms to 1 mole of melamine carbon atoms. . However, since it had a ratio of 2.75 moles of carbon atoms to 1 mole of phosphorus atoms, it was a ratio of 0.92 moles of melamine to 1 mole of phosphorus atoms. Therefore, the fired product obtained contained melamine polymetaphosphate and free polymetaphosphate.
[0046]
It had a pH of 2.40 as a 10 wt% aqueous slurry (25 ° C).
Comparative Example 3
In the step (a), the same procedure as in Example 1 was carried out except that the amount of industrial granular urea collected was 461 g (7.68 mol).
As a fired product, 718 g (theoretical amount 791 g) was obtained. The fired product was cooled and pulverized with a pin disk.
[0047]
The obtained pin disc pulverized product of the fired product had powder characteristics with a bulk specific gravity of 0.6 g / ml and an average particle size of 8.3 μm.
With respect to the obtained fired product, the results of elemental analysis were as follows: carbon 16.7% by weight, nitrogen 39.6% by weight, hydrogen 3.7% by weight, and phosphorus 16.3% by weight. Further, from this result, oxygen in the fired product was calculated to be 23.7% by weight, and had a ratio of 2.82 mol oxygen atom to 1 mol phosphorus atom, and 3 oxygen to 1 mol phosphorus atom of polymetaphosphoric acid. It almost coincided with the ratio (theoretical value) of 0.0 mol of oxygen atoms. It has a ratio of 2.03 moles of nitrogen atoms to 1 mole of carbon atoms in the fired product, and almost coincides with the ratio (theoretical value) of 2.0 moles of nitrogen atoms to 1 mole of melamine carbon atoms. . However, since it had a ratio of 2.65 moles of carbon atoms to 1 mole of phosphorus atoms, it was a ratio of 0.88 moles of melamine to 1 mole of phosphorus atoms. Therefore, the fired product obtained contained melamine polymetaphosphate and free polymetaphosphate.
[0048]
It had a pH of 2.23 as a 10 wt% aqueous slurry (25 ° C).
Example 2
(A) Process
In a 5 L universal mixer (made of stainless steel), 540 g (4.29 mol) of melamine (Nissan Chemical Co., Ltd.) and 108 g (1.80 mol) of industrial granular urea (Nissan Chemical Co., Ltd.) Precipitating silica powder as colloidal silica (Carplex # 80 (registered trademark), manufactured by Shionogi & Co., Ltd., specific surface area 193 m^Three/ G, silica content 95 wt%, primary particle size 10-20 nm) 21 g were collected and mixed for 10 minutes. To this mixture of melamine, urea, and colloidal silica, 443 g (orthophosphoric acid content: 3.84 mol) of an orthophosphoric acid aqueous solution (produced by Tosoh Corporation) having an orthophosphoric acid content of 85% by weight was added and mixed with stirring for 30 minutes. . Further, stirring was maintained for 30 minutes after the end of the addition. Melamine was in a ratio of 1.11 moles per mole of orthophosphoric acid. The addition of this orthophosphoric acid aqueous solution caused a significant exotherm, and water vapor was generated. Thus, 1100 g of a wet powder product was obtained.
[0049]
(B) Process
A total amount of 1100 g of the product obtained in the step (a) was put in a stainless steel bat and fired at 310 ° C. in an electric furnace. The temperature raising time was 310 ° C. in about 4 hours, and the firing temperature of 310 ° C. was maintained for 5 hours. Since some solidification occurs due to dehydration, in order to prevent solidification, the material to be fired at the time of temperature rise was taken out when the temperature reached 150 ° C., and the solidified material was broken to continue the firing. The decomposition of urea and the sublimation of melamine were remarkably recognized by firing. As a fired product, 780 g (theoretical amount: 811 g) was obtained. The fired product was cooled and pulverized with a pin disk.
[0050]
The obtained pin disc pulverized product of the fired product had powder characteristics with a bulk specific gravity of 0.6 g / ml and an average particle size of 7.0 μm.
With respect to the obtained fired product, the results of elemental analysis are as follows: carbon 17.0% by weight, nitrogen 39.5% by weight, hydrogen 5.2% by weight, phosphorus 14.4% by weight, and silica content analysis result. Was 2.4% by weight. Further, from this result, the oxygen in the fired product was calculated to be 21.5% by weight, and had a ratio of 2.89 moles of oxygen atoms to 1 mole of phosphorus atoms, and 3 per mole of phosphorus atoms of polymetaphosphoric acid. It almost coincided with the ratio (theoretical value) of 0.0 mol oxygen atom. It has a ratio of 1.99 moles of nitrogen atoms to 1 mole of carbon atoms in the calcined product, and clearly agrees with the ratio (theoretical value) of 2.0 moles of nitrogen atoms to 1 mole of carbon atoms in melamine did. And it was a ratio of 1.02 mol of melamine to 1 mol of phosphorus atoms because it had a ratio of 3.05 mol of carbon atoms to 1 mol of phosphorus atoms.
[0051]
The product obtained as a result of the differential thermal analysis showed almost no weight loss up to 350 ° C. and showed very good heat resistance.
The fired product is crystalline. As a result of powder X-ray diffraction, the diffraction peak coincided with the diffraction peak of Example 1, and no melamine orthophosphate, melamine pyrophosphate, or melamine was observed.
[0052]
From the above results, the fired product obtained in step (B) was determined to be a mixture of melamine polymetaphosphate and colloidal silica.
The obtained fired product contained 97.6% by weight of melamine polymetaphosphate and 2.4% by weight of colloidal silica, and had a pH of 3.27 as a 10% by weight aqueous slurry (25 ° C.). Moreover, the solubility with respect to water (25 degreeC) showed the very small value as 0.03g / 100ml.
[0053]
Example 3
(A) Process
In a 5 L universal mixer (made of stainless steel), 494 g (3.92 mol) of melamine (Nissan Chemical Co., Ltd.), 148 g (2.47 mol) of industrial granular urea (Nissan Chemical Co., Ltd.), Precipitating silica powder (Carplex # 80 (registered trademark), manufactured by Shionogi & Co., Ltd., silica content 95% by weight, specific surface area 193 m^Three/ G, primary particle size 10 to 20 nm) was collected and mixed for 10 minutes. To this mixture of melamine, urea, and colloidal silica, 443 g (orthophosphoric acid content: 3.84 mol) of an orthophosphoric acid aqueous solution (produced by Tosoh Corporation) having an orthophosphoric acid content of 85% by weight was added and mixed with stirring for 30 minutes. . Further, stirring was maintained for 30 minutes after the end of the addition. Melamine was in a ratio of 1.02 mole per mole of orthophosphoric acid. The addition of this orthophosphoric acid aqueous solution caused a significant exotherm, and water vapor was generated. Thus, 1090 g of a wet powder product was obtained.
[0054]
(B) Process
A total amount of 1090 g of the product obtained in the step (a) was placed in a stainless steel bat and fired at 250 ° C. in an electric furnace. The temperature raising time became 250 ° C. in about 2.5 hours, and the firing temperature of 250 ° C. was maintained for 12 hours. Since some solidification occurs due to dehydration, in order to prevent solidification, the material to be fired at the time of temperature rise was taken out when the temperature reached 150 ° C., and the solidified material was broken to continue the firing. As a fired product, 805 g (theoretical amount: 811 g) was obtained.
[0055]
As a result of firing, adhesion to the stainless steel bat and corrosion of the stainless steel bat were not observed.
With respect to the obtained fired product, the results of elemental analysis were as follows: carbon 17.0 wt%, nitrogen 39.7 wt%, hydrogen 4.8 wt%, phosphorus 14.5 wt%, and silica content analysis results Was 2.3% by weight. Further, from this result, oxygen in the fired product was calculated to be 21.7% by weight, and had a ratio of 2.90 mol oxygen atom to 1 mol phosphorus atom, and 3 oxygen to 1 mol phosphorus atom of polymetaphosphoric acid. It almost coincided with the ratio (theoretical value) of 0.0 mol oxygen atom. It has a ratio of nitrogen atom of 2.00 mol to 1 mol of carbon atom in the fired product, and clearly agrees with the ratio (theoretical value) of 2.0 mol of nitrogen atom to 1 mol of carbon atom of melamine did. And it was a ratio of 1.01 mol of melamine to 1 mol of phosphorus atoms because it had a ratio of 3.03 mol of carbon atoms to 1 mol of phosphorus atoms.
[0056]
The product obtained as a result of the differential thermal analysis showed almost no weight loss up to 350 ° C. and showed very good heat resistance.
The fired product is crystalline. As a result of powder X-ray diffraction, the diffraction peak coincided with the diffraction peak of Example 1, and no melamine orthophosphate, melamine pyrophosphate, or melamine was observed.
[0057]
Therefore, the fired product obtained contained 97.7% by weight of melamine polymetaphosphate and 2.3% by weight of colloidal silica.
Example 4
20.0 kg of orthophosphoric acid aqueous solution (manufactured by Tosoh Corporation) having an orthophosphoric acid content of 85% by weight (173 mol of orthophosphoric acid) was collected in a 30 L polypropylene-equipped container, and melamine (Nissan Chemical Industries) 2.19 kg (17.4 mol) (mixed) was added and mixed, followed by heating at a mixed solution temperature of 80 ° C. for 2 hours to obtain 22.19 kg of an orthophosphoric acid aqueous solution in which melamine was dissolved. This lysate contained 76.6% by weight orthophosphoric acid and 9.87% by weight melamine and had a ratio of 0.10 moles of melamine to 1 mole of orthophosphoric acid.
[0058]
(A) Process
200 L Henschel mixer with jacket (made of stainless steel), 19.6 kg (156 mol) of melamine (manufactured by Nissan Chemical Industries) and 5.0 kg (83.3) of industrial granular urea (manufactured by Nissan Chemical Industries, Ltd.) Mol) and precipitated silica powder (Carplex # 80 (registered trademark), manufactured by Shionogi & Co., Ltd., silica content 95% by weight, specific surface area 193 m)^Three/ G, primary particle diameter 10-20 nm) and 1.1 kg were collected and mixed for 5 minutes.
[0059]
To this mixture of melamine, urea and colloidal silica, 19.9 kg (orthophosphoric acid content 156 mol, melamine content 15.6 mol) of an orthophosphoric acid solution in which the melamine was dissolved was added with stirring for 20 minutes. After completion of the addition, heating steam was passed through the jacket of the Henschel mixer and stirring was continued for 1 hour while heating. As a result, 40.8 kg of a dry powder product was obtained. The product had a composition with a ratio of 1.10 moles of melamine to 1 mole of orthophosphoric acid.
[0060]
(B) Process
The product obtained in step (a) is continuously fired in a double shaft type continuous firing furnace (made of stainless steel) so that the average residence time is 4 hours under conditions of a jacket temperature of 340 ° C. and a furnace firing temperature of 290 ° C. Went. During continuous firing, no adhesion of the fired product was observed in the firing furnace, and no corrosion inside the firing furnace due to phosphoric acid was observed after the firing.
[0061]
The obtained fired product was 31.8 kg (theoretical amount: 33.2 kg). This fired product was a powder having very low hygroscopicity and good fluidity, and could be easily pulverized by a pin disc mill.
The obtained pin disc pulverized product of the fired product had powder characteristics with a bulk specific gravity of 0.6 g / ml and an average particle size of 8.8 μm.
[0062]
With respect to the obtained fired product, the results of elemental analysis were as follows: carbon 17.0 wt%, nitrogen 39.2 wt%, hydrogen 4.4 wt%, phosphorus 14.5 wt%, and silica content analysis Was 3.1% by weight. Further, from this result, oxygen in the fired product was calculated to be 21.8% by weight, and had a ratio of 2.91 mol oxygen atom to 1 mol phosphorus atom, and 3 oxygen to 1 mol phosphorus atom of polymetaphosphoric acid. It almost coincided with the ratio (theoretical value) of 0.0 mol oxygen atom. It has a ratio of 1.98 moles of nitrogen atoms to 1 mole of carbon atoms in the calcined product, and clearly agrees with the ratio (theoretical value) of 2.0 moles of nitrogen atoms to 1 mole of melamine carbon atoms. did. And it was a ratio of 1.01 mol of melamine to 1 mol of phosphorus atoms because it had a ratio of 3.03 mol of carbon atoms to 1 mol of phosphorus atoms.
[0063]
The product obtained as a result of the differential thermal analysis showed almost no weight loss up to 350 ° C. and showed very good heat resistance.
The fired product is crystalline. As a result of powder X-ray diffraction, the diffraction peak coincided with the diffraction peak of Example 1, and no melamine orthophosphate, melamine pyrophosphate, or melamine was observed.
[0064]
From the above results, it was determined that the fired product obtained in step (b) was a mixture of melamine polymetaphosphate and colloidal silica.
Therefore, the fired product obtained contained 96.9% by weight of melamine polymetaphosphate and 3.1% by weight of colloidal silica. It had a pH of 3.45 as a 10 wt% aqueous slurry (25 ° C). Moreover, the solubility with respect to water (25 degreeC) showed the very small value as 0.03g / 100ml.
[0065]
The results of differential thermal analysis and powder X-ray diffraction are shown in FIGS. In the differential thermal analysis, the firing residue at 1000 ° C. is 10.4% by weight because the silica phosphate glass (SiO 2) produced by the reaction of colloidal silica and phosphoric acid.₂・ P₂O_Five).
Example 5
23.0 kg of the calcined product obtained in the step (b) of Example 4 and 1.38 kg of magnesium hydroxide (Kisuma 5 (registered trademark), manufactured by Kyowa Chemical Industry Co., Ltd.), an inorganic basic substance, are added to the Henschel mixer. After mixing, the mixture was pulverized and mixed with a pin disc mill.
[0066]
The obtained pin disc pulverized product of the fired product had powder characteristics with a bulk specific gravity of 0.6 g / ml and an average particle size of 10.0 μm.
The resulting fired product was 91.4 wt% melamine polymetaphosphate, 2.9 wt% colloidal silica, and 5.7 wt% magnesium hydroxide, and had a pH of 7.31 as a 10 wt% aqueous slurry (25 ° C). Had. Moreover, the solubility with respect to water (25 degreeC) showed the very small value as 0.02g / 100ml.
[0067]
As a result of differential thermal analysis, almost no weight loss was observed up to 350 ° C., indicating very good heat resistance.
Comparative Example 4
(A) Process
Into a 10 L type universal mixer (made of stainless steel), 1080 g of melamine (manufactured by Nissan Chemical Industries, Ltd.) (8.57 mol of orthophosphoric acid) was sampled, and an orthophosphoric acid aqueous solution having an orthophosphoric acid content of 85% by weight (with stirring) 886 g (7.68 mol) manufactured by Tosoh Corporation was added and mixed in 30 minutes. Further, stirring was maintained for 30 minutes after the end of the addition. Accordingly, 1930 g of a wet powder product was obtained. The product had a composition with a ratio of 1.11 moles of melamine per mole of orthophosphoric acid.
[0068]
(B) Process
(965) 965 g of the product obtained in the step was placed in a stainless steel bat and baked at 290 ° C. in an electric furnace. The temperature raising time was about 290 ° C. in about 4 hours, and the firing temperature was kept at 290 ° C. for 5 hours. Since some solidification occurs due to dehydration, in order to prevent solidification, the material to be fired at the time of temperature rise was taken out when the temperature reached 150 ° C., and the solidified material was broken to continue the firing. As a fired product, 806 g was obtained. As a result of powder X-ray diffraction, it was confirmed that melamine pyrophosphate was the main component and a small amount of melamine polymetaphosphate was present.
[0069]
Comparative Example 5
965 g of the product obtained in the step (a) of Comparative Example 4 was placed in a stainless steel bat and fired at 310 ° C. in an electric furnace. The temperature raising time was 310 ° C. in about 4 hours, and the firing temperature was maintained at 310 ° C. for 5 hours. Since some solidification occurs due to dehydration, in order to prevent solidification, the material to be fired at the time of temperature rise was taken out when the temperature reached 150 ° C., and the solidified material was broken to continue the firing. Substantial melamine sublimation was observed upon firing. Although the obtained fired product was 740 g, the surface was darkened by the polyphosphoric acid produced by firing, and the fired product was remarkably attached to the stainless steel vat and produced by detachment of melamine from melamine polyphosphate. Polyphosphoric acid caused significant corrosion on the stainless steel bat. Since the obtained fired product contained free polyphosphoric acid, it was not hygroscopic and could not be used as a flame retardant. As a result of powder X-ray diffraction, the fired product was determined to be melamine polymetaphosphate, but a shift was observed in the peak position.
[0070]
The resulting fired product had a very low pH of 2.0 as a 10 wt% aqueous slurry (25 ° C). Also in the differential thermal analysis, a weight loss due to melamine desorption was observed from 280 ° C., and a weight loss of 4.0% was shown at 350 ° C., and the heat resistance was not good.
Comparative Example 6
1100 g of the wet powder product obtained in the step (a) shown in Example 2 was placed in a stainless steel bat and fired at 200 ° C. in an electric furnace. The temperature raising time became 200 ° C. in about 2 hours, and the firing temperature was maintained at 200 ° C. for 5 hours. Since some solidification occurs due to dehydration, the product was taken out when the temperature of the material to be fired reached 150 ° C. at the time of temperature rise. The fired product obtained was 920 g.
[0071]
As a result of powder X-ray diffraction, the diffraction peak of the product coincided with the diffraction peak of melamine pyrophosphate, and formation of melamine polymetaphosphate was not observed.
[0072]
【The invention's effect】
The product obtained by the method of the present invention was confirmed to be melamine polymetaphosphate (crystalline) by elemental analysis, powder X-ray diffraction, differential thermal analysis and the like.
Further, unlike the conventionally known melamine polyphosphate and ammonium polyphosphate / melamine double salt, the melamine polymetaphosphate of the present invention has a solubility of 0.10 g / 100 ml or less with respect to water (25 ° C.), that is, Examples Having a solubility of 0.02 to 0.03 g / 100 ml in water (25 ° C.) as described in, and a pH of 2.5 to 4.5 as a 10 wt% aqueous slurry (25 ° C.) ing.
[0073]
According to the production method of the present invention, melamine polymetaphosphate can be efficiently produced basically by a simple operation of mixing and baking. This melamine polymetaphosphate is a flame retardant, unlike conventional melamine phosphate, excellent in heat resistance and water resistance, excellent in powder properties such as pulverization, dispersibility, and fluidity, and more excellent in high phosphorus content. Show flame retardancy.
[0074]
Melamine polymetaphosphate of the present invention is a thermosetting resin such as phenol resin, epoxy resin, polyurethane, unsaturated polyester, polyamide, aromatic polyamide, polyethylene oxide, polycarbonate, polyolefin (polyethylene, polypropylene, polystyrene, etc.), polyphenylene ether, modified It is useful as a flame retardant for a wide range of resins such as thermoplastic resins such as polyphenylene ether, rubber-modified styrene acrylonitrile-butadiene-styrene (ABS), polyester, polysulfone, polybutylene terephthalate, and vinyl chloride, copolymers thereof, and alloys. Moreover, it is useful as a flame retardant for these resin molded products, resin-containing paints, adhesives, fibers, fiber products and the like.
[0075]
Melamine polymetaphosphate of the present invention is a reinforcing agent such as glass fiber, carbon fiber, potassium titanate whisker, heat stabilizer, light stabilizer, antioxidant, antistatic agent, pigment, filler, lubricant, plasticizer, It can be used in combination with those usually used in the production of plastics materials such as coupling agents. The melamine polymetaphosphate of the present invention can be used in combination with other phosphorus flame retardants, bromine flame retardants and the like.
[0076]
Furthermore, the melamine polymetaphosphate of this invention can be used also as resin stabilizers other than a flame retardant.
[Brief description of the drawings]
FIG. 1 is a differential thermal analysis diagram of a mixture of melamine polymetaphosphate and colloidal silica obtained in Example 4 (pin disk pulverized product).
2 is a powder X-ray diffraction pattern of a mixture of melamine polymetaphosphate and colloidal silica (pin disk pulverized product) obtained in Example 4. 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 (3)

  Solubility of 0.01-0.10 g / 100 ml in water (25 ° C.), pH of 2.5-4.5 as a 10 wt% aqueous slurry (25 ° C.) and 1.0 per mol of phosphorus atom Melamine polymetaphosphate, characterized in that it has a ratio of ˜1.1 mol of melamine. The following steps (a) and (b):
(A) Melamine, urea, and an orthophosphoric acid aqueous solution containing 40% by weight or more of orthophosphoric acid in a ratio of 1.0 to 1.5 moles of melamine per mole of orthophosphoric acid, and orthophosphoric acid 1 Urea is mixed in a molar ratio of 0.1 to 1.5 at a temperature of 0 to 140 ° C. to form a reaction mixture, and the reaction mixture is subjected to moisture at a temperature of 0 to 140 ° C. A step of obtaining a powdery product comprising a double salt of orthophosphoric acid, melamine and urea by stirring while removing the powder, and (b) the powdery product obtained in step (a) is consolidated. A step of obtaining melamine polymetaphosphate by baking at a temperature of 240 to 340 ° C. for 0.1 to 30 hours while preventing,
The method for producing melamine polymetaphosphate according to claim 1, comprising: Further, in the step (a), colloidal silica is added in a ratio of 16 parts by weight or less with respect to 100 parts by weight of melamine, and the colloidal silica is contained in the powdered product. Production method of melamine polymetaphosphate.

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