JP4528482B2 - Polyamide particles and method for producing the same - Google Patents

Description

【００１６】
ポリアミド粒子は、好ましくはアミド形成モノマー（Ａ）５０〜１００重量％及びアミド形成モノマー（Ｂ）０〜５０重量％から合成されるポリアミドからなること、
さらに好ましくはアミド形成モノマー（Ａ）６０〜１００重量％とアミド形成モノマー（Ｂ）０〜４０重量％から合成されるポリアミドからなること、
特に好ましくはアミド形成モノマー（Ａ）６５〜１００重量％とアミド形成モノマー（Ｂ）０〜３５重量％から合成されるポリアミドからなることが好ましい。
ポリアミドのアミド形成モノマー（Ａ）が５０重量％未満では結晶化が起こりやすく、球状粒子が得られるために好ましくない。
【００１７】
ポリアミド形成性モノマー（Ａ）としては、炭素数９〜２２のω−アミノカルボン酸、炭素数９〜２２のラクタム、或いは炭素数９〜２２のジアミンと炭素数９〜２２のジカルボン酸から合成されるもの及び／又はそれらの塩から選ばれる少なくとも一種の脂肪族、脂環族及び芳香族を含むポリアミド形成性モノマーが使用される。
【００１８】
ポリアミド形成性モノマー（Ｂ）としては、炭素数４〜８のω−アミノカルボン酸、炭素数４〜８のラクタム、或いは炭素数２〜８のジアミンと炭素数２〜８のジカルボン酸から合成されるもの及び／又はそれらの塩から選ばれる少なくとも一種の脂肪族、脂環族及び芳香族を含むポリアミド形成性モノマーが使用される。
本発明のポリアミド粒子は、脂肪族及び／又は脂環族からなるポリアミド粒子が好ましい。
【００１９】
ジアミンとジカルボン酸から合成されるもの及び／又はそれらの塩において、ジアミンとしては、脂肪族ジアミン、脂環式ジアミン及び芳香族ジアミン又はこれらの誘導体から選ばれる少なくとも一種のジアミン化合物などを挙げることが出来、
ジカルボン酸としては、脂肪族ジカルボン酸、脂環式ジカルボン酸及び芳香族ジカルボン酸又はこれらの誘導体から選ばれる少なくとも一種のジカルボン酸化合物などを挙げることが出来る。
特に、ジアミンとジカルボン酸から合成されるもの及び／又はそれらの塩において、脂肪族ジアミン化合物と脂肪族ジカルボン酸化合物の組合せを使用することが好ましい。
ジアミンとジカルボン酸のモル比（ジアミン／ジカルボン酸）は０．９〜１．１の範囲が好ましく、０．９３〜１．０７の範囲がさらに好ましく、０．９５〜１．０５の範囲がより好ましく、０．９７〜１．０３の範囲が特に好ましい。この範囲から外れると高分子量化しにくくなる場合があるため好ましくない。
【００２０】
ジアミンとジカルボン酸から合成されるもの及び／又はそれらの塩において、炭素数２〜２２のジアミンの具体例としては、エチレンジアミン、トリメチレンジアミン、テトラメチレンジアミン、ヘキサメチレンジアミン、ヘプタメチレンジアミン、オクタメチレンジアミン、ノナメチレンジアミン、デカメチレンジアミン、ウンデカメチレンジアミン、ドデカメチレンジアミン、２，２，４−トリメチルヘキサメチレンジアミン、２，４，４−トリメチルヘキサメチレンジアミン、３−メチルペンタメチレンジアミンなどの炭素数２〜２２の脂肪族ジアミンなどのジアミン化合物を挙げることが出来、
ジカルボン酸の具体例としては、シュウ酸、コハク酸、グルタル酸、アジピン酸、ピメリン酸、スベリン酸、アゼライン酸、セバシン酸、ドデカン二酸のような炭素数２〜２２の脂肪族ジカルボン酸などのジカルボン酸化合物を挙げることが出来る。
ラクタムとしては、ε−カプロラクタム、ω−エナントラクタム、ω−ウンデカラクタム、ω−ドデカラクタム、２−ピロリドンなどの炭素数４〜２０の脂肪族ラクタムなどを挙げることが出来る。
ω−アミノカルボン酸としては、６-アミノカプロン酸、７−アミノヘプタン酸、８−アミノオクタン酸、１０−アミノカプリン酸、１１−アミノウンデカン酸、１２−アミノドデカン酸などの炭素数４〜２０の脂肪族ω−アミノカルボン酸などを挙げることが出来る。
【００２１】
ポリアミドとしては、公知の種々のものを挙げることができる。例えば、環状アミドの開環重合、あるいはジカルボン酸とジアミンの重縮合などで得られる。モノマーとしては、ω−ラウロラクタム等の環状アミドを開環重合、ε−アミノカプロン酸、ω−アミノドデカン酸、ω−アミノウンデカン酸などのアミノ酸の重縮合で得られる。
【００２２】
ポリアミドの一例として、ポリアミド１０、ポリアミド１１、ポリアミド１２、ポリアミド１４、ポリアミド１６、ポリアミド１２−６、ポリアミド１２−６６、ポリアミド１２−４、ポリアミド１１−６などポリアミド形成性モノマー（Ａ）を５０〜１００重量％含むものを挙げることが出来る。
【００２３】
本発明のポリアミド粒子は、ポリアミド、溶媒、水及び非溶媒とを混合して均一な溶液を製造し、該均一な溶液を製造後溶液温度５〜６０℃で１分〜４８時間の間で析出させる方法で製造することが出来る。
さらに本発明のポリアミド粒子は、ポリアミドと溶媒からなるポリアミド溶液と、水及び非溶媒とを混合して均一な溶液を製造し、該均一な溶液を製造後溶液温度５〜６０℃で１分〜４８時間の間で析出させる方法で製造することが出来る。
特に本発明のポリアミド粒子は、ポリアミドと良溶媒からなるポリアミド溶液と、水及び非溶媒とを混合して一時的に均一な溶液を作成し、該均一な溶液を製造後溶液温度５〜６０℃で１分〜４８時間の間で析出させる方法で製造することが出来る。
上記ポリアミド溶液、水及び非溶媒とを混合して均一な溶液を製造する場合、ポリアミド溶液５０〜９５重量％と、水及び非溶媒の合計量が５〜５０重量％が好ましい。ポリアミド溶液、水及び非溶媒の合計１００重量％に対し、水及び非溶媒の合計量が５０重量％を超えると、重合体の析出時間が速く不定型粒子や塊状粒子あるいは比表面積の大きな多孔質粒子などが生成して、楕円状、筒状、ダンベル状または鼓状の形状を有する粒子が得られにくいため好ましくない。
【００２４】
本発明のポリアミドの分子量は、好ましくは２，０００〜１００，０００の範囲であり、さらに好ましくは５，０００〜４０，０００の範囲である。
【００２５】
ポリアミドの良溶媒としては、芳香族フェノール系溶媒、または有機酸などを挙げることが出来、具体例として、フェノール、０−クレゾール、ｍ−クレゾール、ｐ−クレゾール、クロロフェノールなどの芳香族フェノール系溶媒、蟻酸などの有機酸などを挙げることができる。
【００２６】
本発明のポリアミド溶液は、ポリアミドが０．１〜３０重量％と良溶媒が９９．９〜７０重量％が好ましく、さらにポリアミドが０．２〜２５重量％と良溶媒が９９．８〜７５重量％の範囲が好ましい。ポリアミド溶液中でポリアミドの割合が３０重量％を越えると、溶解しにくくなったり、均一な溶液にならないことがあり、さらに溶解しても溶液の粘度が高くなり、取扱いにくくなるので好ましくない。ポリアミドの割合が０．１重量％より低くなると、ポリマー濃度が低く、製品の生産性が低くなるので好ましくない。
【００２７】
非溶媒は、ポリアミドを難溶性の水と混ざる溶媒を用いることが出来、特に炭素数１〜４の脂肪族アルコールが好ましい。
非溶媒の一例として、メタノール、エタノール、ｎ−プロパノ−ル、イソプロパノ−ル、ｎ−ブタノ−ル、２−ブタノール、ｔｅｒｔ−ブタノールなどの炭素数１〜４の脂肪族アルコールを挙げることが出来、これらの混合物を用いることができる。
非溶媒と水とを含むポリアミドの析出水溶液としては、非溶媒が５０〜１００重量％（１００重量％を除く）と、水が０〜５０重量％（０重量％を除く）からなることが好ましく、さらに好ましくは非溶媒が９５〜５０重量％と水が５〜５０重量％からなることが好ましい。
上記析出水溶液は、水を含まない場合、ポリアミド粒子の析出が遅く、本発明の粒子形状が得られない。析出水溶液は、水を５０重量％超えて含むと、得られるポリアミド粒子は凝集した粒子となり好ましくない。
【００２８】
本発明において、ポリアミド溶液、水及び非溶媒の添加順序は、得られる混合溶液の均一性が保たれれば、特に制限はなく、ポリアミド溶液に水及び非溶媒を加えてもよく、水及び非溶媒にポリアミド溶液を加えてもよい。
本発明においては、ポリアミド溶液、水及び非溶媒の３者が肉眼で観察して、一時的に均一に相溶することが重要であり、ポリアミド溶液、水及び非溶媒のそれぞれの割合は、一時的に均一に相溶の溶液となる組成を選ぶ必要がある。これにより、均一相溶の溶液を形成させて、時間的な経過を経て、本発明のポリアミド粒子を析出させるものである。
【００２９】
ポリアミド溶液と、水及び非溶媒との混合時間は、０．１秒〜２４０分程度が好ましく、さらに１秒〜１２０分間が好ましく、一時的にも均一に相溶することが重要である。ポリアミド溶液と析出水溶液との混合は、必要ならば、適当な撹拌を加えることができる。
本発明において、ポリアミド溶液と析出水溶液との混合物が均一な溶液を形成すると、その後撹拌の必要はなく、ポリアミド粒子が析出し始める時以降は、静置しておくことが好ましい。
【００３０】
ポリアミド溶液と析出水溶液との均一な溶液からポリアミド粒子を析出させる温度は、５〜６０℃が好ましい。温度によっては、溶液が均一になる組成範囲が広くなることがある。温度が５℃より低いと、均一になる領域が狭くなる溶媒組成の場合がある。温度が６０℃より高いと、溶媒の蒸気圧が高くなり好ましくない。
ポリマーが析出するのに要する時間は、１分〜４８時間の間が好ましく、さらに３分〜１０時間が好ましい。
【００３１】
析出したポリアミド粒子は、溶液から遠心分離、濾過、デカンテイションなどの通常の方法で分離することができる。例えば、縣濁した溶液を、メタノールなどで希釈して、遠心分離に掛けてもよい。数回メタノールで洗浄して遠心分離に掛けてもよい。次に熱風乾燥、真空乾燥に供してもよい。
【００３２】
本発明のポリアミド粒子は触媒担持体、粉体塗料、電子写真のトナーなどの工業材料、化粧品などの日用品などに、またエレクトロニクス用、医療用、食品工業分野用の機能性粒子として用いることができる。
【００３３】
【実施例】
以下、実施例により本発明を具体的に説明するが、本発明はこれらの実施例に限定されるものではない。粒子形状、比表面積などの測定は次のようにして行った。
【００３４】
・粒子の観察：走査型電子顕微鏡写真（拡大倍率５０００倍）を用いて、写真より粒子２０個を任意で選び、その粒子形状を観察し、粒子長及び粒子径を測定する。粒子長及び粒子径は、２０個の平均値とする。
【００３５】
・比表面積：粒子の比表面積は、窒素吸着によるＢＥＴ法で３点測定で行う。
【００３６】
［実施例１］
ポリアミド１２（宇部興産製３０１４Ｕ，分子量１４，０００）を、濃度２重量％ｍ−クレゾール溶液とした。ポリアミドのｍ−クレゾール溶液５０重量部に、１−プロパノール２５重量部と水２５重量部とを、マグネチックスターラーで攪拌しながら添加し、均一に相溶した溶液を得た。攪拌を停止し、溶液を静置し、静置３０分後にポリマーが析出してきた。温度は２５℃で行った。静置２４時間後に、デカンテイションして、遠心分離でポリマー粒子を分離した。得られた粒子を洗浄した後、走査型電子顕微鏡にて観察し、その写真を図１に示す。
【００３７】
得られた粒子を走査型電子顕微鏡で観察したところ、ダンベル状粒子であった。その粒子長は、２．６５μｍであり、変動係数は１２％であり、Ｌ／ｄは４．５であった。粒子径の分布がシャープな、分散性に優れた粒子であった。比表面積は３．５ｍ^２／ｇであった。
【００３８】
［実施例２］
ポリアミドクレゾール溶液６３重量部、１−プロパノ−ル３１重量部、水６重量部としたほかは、実施例１と同様にした。得られた粒子を観察したところ、ダンベル状の分散性の優れた粒子であった。粒子長は、３．８μｍ、変動係数は１３％であり、Ｌ／ｄは４．１であった．比表面積は３．６ｍ^２／ｇであった。得られた粒子を洗浄した後、走査型電子顕微鏡にて観察し、その写真を図２に示す。
【００３９】
［実施例３］
ポリアミド１２−６共重合体（宇部興産製７１１５ｕ、ポリアミド１２ 重量％含有）を用いた以外は、実施例２と同様にしてポリマー粒子を得た。ダンベル状粒子であり、粒子長は、２．３μｍ、変動係数は１０％であり、Ｌ／ｄは４．４であった．比表面積は５．６ｍ^２／ｇであった。
【００４０】
［比較例１］
ポリアミド６（宇部興産製１０３０Ｂ、分子量１３、０００）を、濃度２重量％ｍ−クレゾール溶液１４重量とし、メタノール７２重量部と、水１４重量部を添加して攪拌し、均一な溶液になった。１時間後に析出したポリマーをろ過した。得られたポリマーを走査型電子顕微鏡で観察すると、粒子径は、８．４μｍの球状粒子であった。比表面積は１０．６ｍ^２／ｇであった。
【００４１】
［比較例２］
ポリアミド１２の２重量％のクレゾール溶液４０重量部に、１−プロパノ−ル４０重量部、水２０重量部としたほかは、実施例１と同様にした。得られた析出物は、無定形の粒子が凝集した塊状となっていた。
【００４２】
［比較例３］
ポリアミド１２の２重量％のクレゾール溶液６７重量部に、１−プロパノ−ル３３重量部を添加し、水を加えなかったほかは実施例１と同様にした。溶液は均一になったが、２日間経過してもポリアミドは析出しなかった。
【００４３】
【発明の効果】
本発明のポリアミド粒子は、特定の形状を有し、特定の粒子長及び粒子径であり、粒子径分布が狭い、均一で、分散性の優れた粒子である。
【図面の簡単な説明】
【図１】 本発明の実施例１で得られたポリアミド粒子の走査型電子顕微鏡写真である。
【図２】 本発明の実施例２で得られたポリアミド粒子の走査型電子顕微鏡写真である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to polyamide particles having moderate porosity with excellent dispersibility and having a cylindrical shape or a dumbbell shape, and a method for producing the same.
[0002]
[Prior art]
As for the spherical particles, Japanese Patent Application Laid-Open No. 5-70598 discloses that a powder of nylon 11 is obtained by spraying a solution of nylon 11 in a molten state and cooling.
Japanese Patent Application Laid-Open No. 6-256529 discloses polymer particles characterized by dissolving a resin in a non-aqueous solvent, adding a specific proportion of a poor solvent, and adding a second non-aqueous solvent for cosmetics and toners. Is disclosed.
JP-A-8-73602 discloses a production method for obtaining spherical polyamide particles by using lactam as an insoluble polymerization medium as a coating powder.
[0003]
JP-A-2-215838 discloses a method for producing polymer particles, in which a polymer and a solvent such as polyester are heated to a melting point or higher and then cooled to a melting point or higher to obtain polymer particles.
Japanese Patent No. 3165184 discloses a method characterized in that a polymer such as nylon, ethylene glycol, and a polar solvent are heated and dissolved in a dissolution tank and then cooled to obtain specific spherical polymer particles.
Japanese Patent Application Laid-Open No. 9-316206 discloses a technique for dissolving and precipitating polyamide in a solvent and water that are dissolved for the first time under high temperature and high pressure.
[0004]
As a method for obtaining porous particles, Japanese Patent Laid-Open No. 1-278541 discloses that a porous uniform polymer particle is obtained by spraying into a gas phase from a polymer solution, charging it, and then immersing it in a coagulation liquid by cooling. It is disclosed.
Japanese Patent Application Laid-Open No. 3-26729 discloses a method of obtaining porous polymer particles by crystallization with two types of solvents and non-solvents having different hydrogen bond indices.
As a porous particle, JP-A-1-230630 discloses a method characterized in that it is produced at a supersaturated temperature by anionic polymerization of lactam.
Japanese Patent No. 2568392 discloses that a single spherulite particle is obtained by dissolving in a phase separation solvent at a high temperature and then cooling to induce phase separation.
[0005]
[Problems to be solved by the invention]
Polyamide particles relating to spherical particles and porous particles are disclosed. These are used as daily necessities such as cosmetics and adsorbents, or industrial materials such as powder paints, abrasives and catalyst carriers.
[0006]
Unlike spherical particles, elliptical, cylindrical, dumbbell-shaped or drum-shaped particles have a large coefficient of friction.
An object of the present invention is to provide polyamide particles having an oval shape, a cylindrical shape, a dumbbell shape, or a drum shape, and moderately porous, and a method for producing the same.
[0007]
[Means for Solving the Problems]
The first of the present invention is characterized in that the particle length is 0.5 to 25 μm, the L / D (particle length / particle diameter) is 3 to 50, and the specific surface area is 0.1 to 10 m ² / g. To provide polyamide particles.
[0008]
In the second aspect of the present invention, the polyamide particles are composed of a polyamide synthesized from 50 to 100% by weight of the amide-forming monomer (A) and 0 to 50% by weight of the amide-forming monomer (B), and the amide-forming monomer (A) is carbon. Provided is a polyamide particle which is an amide-forming monomer having 9 to 22 and the amide-forming monomer (B) is an amide-forming monomer having 2 to 8 carbon atoms.
[0009]
According to a third aspect of the present invention, the polyamide particles are mixed with a polyamide solution composed of polyamide and a solvent, and a polyamide non-solution containing water and a non-solvent to produce a uniform solution. Provided is a polyamide particle which is a polyamide particle which precipitates at a temperature of 5 to 60 ° C. for 1 minute to 48 hours.
[0010]
4th of this invention provides the manufacturing method of the polyamide particle as described in 1st or 2nd invention.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The polyamide particles of the present invention have a particle length of 0.5 to 25 μm, an L / D (particle length / particle diameter) of 3 to 50, and a specific surface area of 0.1 to 10 m ² / g. Polyamide particles.
The polyamide particles of the present invention are particles having an elliptical shape, a cylindrical shape, a dumbbell shape, or a drum shape.
[0012]
The particle length of the polyamide particles is 0.5 to 25 μm, preferably 1 to 10 μm, more preferably 1 to 8 μm, and particularly preferably 1 to 5 μm.
[0013]
The L / D (particle length / particle diameter) of the polyamide particles is in the range of 3-50, preferably in the range of 3-20, more preferably in the range of 3-15, and particularly preferably in the range of 3-10.
Here, L / D is a value obtained by dividing the particle length by the particle diameter, and the particle diameter is a particle diameter in the vicinity of the center of the particle. For example, the particle diameter is the diameter of the central portion of particles having an elliptical shape and a cylindrical shape, and is the diameter of a thin portion of the central portion of particles having a dumbbell shape and a drum shape.
[0014]
The specific surface area of the polyamide particles is 0.1 to 10 m ² / g, preferably 0.5 to 8 m ² / g, more preferably 1 to 7 m ² / g, and particularly preferably ² to 6 m ² / g.
[0015]
The coefficient of variation of the particle length distribution of the polyamide particles is preferably 20% or less, more preferably 15% or less. When the variation coefficient of the particle length distribution of the polyamide particles exceeds 20%, the variation in the particle length distribution is large, it is difficult to obtain a uniform product, and the friction coefficient is excessively increased. The variation coefficient of the particle length distribution of the polyamide particles can be calculated according to the mathematical formula (1).
[Expression 1]

[0016]
The polyamide particles preferably comprise a polyamide synthesized from 50 to 100% by weight of the amide-forming monomer (A) and 0 to 50% by weight of the amide-forming monomer (B),
More preferably, it comprises a polyamide synthesized from 60 to 100% by weight of the amide-forming monomer (A) and 0 to 40% by weight of the amide-forming monomer (B).
It is particularly preferable that the polyamide is synthesized from 65 to 100% by weight of the amide-forming monomer (A) and 0 to 35% by weight of the amide-forming monomer (B).
If the polyamide amide-forming monomer (A) is less than 50% by weight, crystallization is likely to occur and spherical particles are obtained, which is not preferable.
[0017]
The polyamide-forming monomer (A) is synthesized from ω-aminocarboxylic acid having 9 to 22 carbon atoms, lactam having 9 to 22 carbon atoms, or diamine having 9 to 22 carbon atoms and dicarboxylic acid having 9 to 22 carbon atoms. Polyamide-forming monomers containing at least one aliphatic, alicyclic and aromatic selected from those and / or their salts are used.
[0018]
The polyamide-forming monomer (B) is synthesized from a ω-aminocarboxylic acid having 4 to 8 carbon atoms, a lactam having 4 to 8 carbon atoms, or a diamine having 2 to 8 carbon atoms and a dicarboxylic acid having 2 to 8 carbon atoms. Polyamide-forming monomers containing at least one aliphatic, alicyclic and aromatic selected from those and / or their salts are used.
The polyamide particles of the present invention are preferably polyamide particles composed of aliphatic and / or alicyclic groups.
[0019]
Examples of diamines synthesized from diamines and dicarboxylic acids and / or salts thereof include at least one diamine compound selected from aliphatic diamines, alicyclic diamines, aromatic diamines, and derivatives thereof. Done,
Examples of the dicarboxylic acid include at least one dicarboxylic acid compound selected from aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, aromatic dicarboxylic acid, and derivatives thereof.
In particular, it is preferable to use a combination of an aliphatic diamine compound and an aliphatic dicarboxylic acid compound in one synthesized from a diamine and a dicarboxylic acid and / or a salt thereof.
The molar ratio of diamine to dicarboxylic acid (diamine / dicarboxylic acid) is preferably in the range of 0.9 to 1.1, more preferably in the range of 0.93 to 1.07, and more preferably in the range of 0.95 to 1.05. The range of 0.97 to 1.03 is particularly preferable. If it is out of this range, it may be difficult to increase the molecular weight.
[0020]
Specific examples of diamines having 2 to 22 carbon atoms synthesized from diamines and dicarboxylic acids and / or their salts include ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylene. Carbons such as diamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 3-methylpentamethylenediamine Diamine compounds such as aliphatic diamines of 2 to 22 can be mentioned,
Specific examples of the dicarboxylic acid include oxalic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and aliphatic dicarboxylic acid having 2 to 22 carbon atoms such as dodecanedioic acid. A dicarboxylic acid compound can be mentioned.
Examples of the lactam include aliphatic lactams having 4 to 20 carbon atoms such as ε-caprolactam, ω-enantolactam, ω-undecalactam, ω-dodecalactam, and 2-pyrrolidone.
The ω-aminocarboxylic acid has 6 to 20 carbon atoms such as 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 10-aminocapric acid, 11-aminoundecanoic acid, 12-aminododecanoic acid. Aliphatic ω-aminocarboxylic acid and the like can be mentioned.
[0021]
Examples of the polyamide include various known ones. For example, it can be obtained by ring-opening polymerization of a cyclic amide or polycondensation of a dicarboxylic acid and a diamine. The monomer is obtained by ring-opening polymerization of a cyclic amide such as ω-laurolactam and polycondensation of amino acids such as ε-aminocaproic acid, ω-aminododecanoic acid, ω-aminoundecanoic acid.
[0022]
As an example of polyamide, polyamide-forming monomer (A) such as polyamide 10, polyamide 11, polyamide 12, polyamide 14, polyamide 16, polyamide 12-6, polyamide 12-66, polyamide 12-4, polyamide 11-6, 50 to The thing containing 100 weight% can be mentioned.
[0023]
The polyamide particles of the present invention are prepared by mixing a polyamide, a solvent, water and a non-solvent to produce a uniform solution, and after the production of the uniform solution, precipitation is performed at a solution temperature of 5 to 60 ° C. for 1 minute to 48 hours. It can be manufactured by the method of making it.
Furthermore, the polyamide particles of the present invention are prepared by mixing a polyamide solution composed of polyamide and a solvent, water and a non-solvent to produce a uniform solution, and after producing the uniform solution, the solution temperature is 5 to 60 ° C. for 1 minute to It can be produced by a method of precipitation for 48 hours.
In particular, the polyamide particles of the present invention are prepared by mixing a polyamide solution composed of polyamide and a good solvent, water and a non-solvent to temporarily create a uniform solution, and after the production of the uniform solution, the solution temperature is 5 to 60 ° C. Can be produced by a method of precipitation in 1 minute to 48 hours.
When a uniform solution is produced by mixing the polyamide solution, water and a non-solvent, the polyamide solution is preferably 50 to 95% by weight and the total amount of water and the non-solvent is 5 to 50% by weight. When the total amount of water and non-solvent exceeds 50% by weight with respect to the total of 100% by weight of the polyamide solution, water and non-solvent, the precipitation time of the polymer is fast and the porous particles have a large irregular surface shape, massive particles or a large specific surface area. This is not preferable because particles are generated and it is difficult to obtain particles having an elliptical shape, a cylindrical shape, a dumbbell shape, or a drum shape.
[0024]
The molecular weight of the polyamide of the present invention is preferably in the range of 2,000 to 100,000, more preferably in the range of 5,000 to 40,000.
[0025]
Examples of good solvents for polyamide include aromatic phenol solvents or organic acids. Specific examples include aromatic phenol solvents such as phenol, 0-cresol, m-cresol, p-cresol, and chlorophenol. And organic acids such as formic acid.
[0026]
The polyamide solution of the present invention is preferably 0.1 to 30% by weight of polyamide and 99.9 to 70% by weight of good solvent, and further 0.2 to 25% by weight of polyamide and 99.8 to 75% by weight of good solvent. % Range is preferred. If the proportion of polyamide in the polyamide solution exceeds 30% by weight, it may be difficult to dissolve or a uniform solution may not be obtained, and even if further dissolved, the viscosity of the solution becomes high and handling becomes unfavorable. If the ratio of the polyamide is lower than 0.1% by weight, the polymer concentration is low and the productivity of the product is low, which is not preferable.
[0027]
As the non-solvent, a solvent in which polyamide is mixed with hardly soluble water can be used, and an aliphatic alcohol having 1 to 4 carbon atoms is particularly preferable.
Examples of non-solvents include aliphatic alcohols having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, tert-butanol, Mixtures of these can be used.
As an aqueous solution for precipitation of polyamide containing a non-solvent and water, the non-solvent is preferably composed of 50 to 100% by weight (excluding 100% by weight) and water is composed of 0 to 50% by weight (excluding 0% by weight). More preferably, the non-solvent is composed of 95 to 50% by weight and water is composed of 5 to 50% by weight.
When the precipitation aqueous solution does not contain water, the precipitation of polyamide particles is slow and the particle shape of the present invention cannot be obtained. When the precipitation aqueous solution contains water in an amount exceeding 50% by weight, the obtained polyamide particles are not preferable because they become aggregated particles.
[0028]
In the present invention, the order of addition of the polyamide solution, water and non-solvent is not particularly limited as long as the uniformity of the resulting mixed solution is maintained, and water and non-solvent may be added to the polyamide solution. A polyamide solution may be added to the solvent.
In the present invention, it is important that the polyamide solution, water, and non-solvent are observed with the naked eye, and are temporarily and uniformly compatible. The proportions of the polyamide solution, water, and non-solvent are Therefore, it is necessary to select a composition that provides a uniformly compatible solution. As a result, a homogeneous solution is formed, and the polyamide particles of the present invention are deposited over time.
[0029]
The mixing time of the polyamide solution, water and the non-solvent is preferably about 0.1 second to 240 minutes, more preferably 1 second to 120 minutes, and it is important that the polyamide solution is uniformly even temporarily. The mixing of the polyamide solution and the precipitation aqueous solution can be performed with appropriate stirring if necessary.
In the present invention, when the mixture of the polyamide solution and the precipitation aqueous solution forms a uniform solution, it is not necessary to stir thereafter, and it is preferable to leave it after the polyamide particles start to precipitate.
[0030]
The temperature at which the polyamide particles are precipitated from a uniform solution of the polyamide solution and the precipitation aqueous solution is preferably 5 to 60 ° C. Depending on the temperature, the composition range in which the solution becomes uniform may be widened. When the temperature is lower than 5 ° C., the solvent composition may become narrower in the uniform region. If the temperature is higher than 60 ° C., the vapor pressure of the solvent becomes high, which is not preferable.
The time required for the polymer to precipitate is preferably between 1 minute and 48 hours, and more preferably between 3 minutes and 10 hours.
[0031]
The precipitated polyamide particles can be separated from the solution by ordinary methods such as centrifugation, filtration, and decantation. For example, the suspended solution may be diluted with methanol and centrifuged. It may be washed several times with methanol and centrifuged. Next, you may use for hot air drying and vacuum drying.
[0032]
The polyamide particles of the present invention can be used as industrial particles such as catalyst carriers, powder coatings, electrophotographic toners, daily necessities such as cosmetics, and as functional particles for electronics, medical, and food industries. .
[0033]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. Measurement of particle shape, specific surface area, etc. was performed as follows.
[0034]
-Observation of particles: Using a scanning electron micrograph (magnification magnification 5000 times), 20 particles are arbitrarily selected from the photograph, the particle shape is observed, and the particle length and particle diameter are measured. The particle length and particle diameter are 20 average values.
[0035]
Specific surface area: The specific surface area of the particles is measured by three-point measurement by the BET method using nitrogen adsorption.
[0036]
[Example 1]
Polyamide 12 (Ube Industries 3014U, molecular weight 14,000) was used as a 2 wt% m-cresol solution. 25 parts by weight of 1-propanol and 25 parts by weight of water were added to 50 parts by weight of a polyamide m-cresol solution while stirring with a magnetic stirrer to obtain a uniformly compatible solution. Stirring was stopped, the solution was allowed to stand, and a polymer was precipitated after 30 minutes of standing. The temperature was 25 ° C. After 24 hours of standing, the polymer particles were decanted and separated by centrifugation. The obtained particles were washed and then observed with a scanning electron microscope, and a photograph thereof is shown in FIG.
[0037]
When the obtained particles were observed with a scanning electron microscope, they were dumbbell-shaped particles. The particle length was 2.65 μm, the coefficient of variation was 12%, and L / d was 4.5. The particles had a sharp particle size distribution and excellent dispersibility. The specific surface area was 3.5 m ² / g.
[0038]
[Example 2]
The same procedure as in Example 1 was performed except that 63 parts by weight of the polyamide cresol solution, 31 parts by weight of 1-propanol, and 6 parts by weight of water were used. The obtained particles were observed to be dumbbell-shaped particles having excellent dispersibility. The particle length was 3.8 μm, the coefficient of variation was 13%, and L / d was 4.1. The specific surface area was 3.6 m ² / g. The obtained particles were washed and then observed with a scanning electron microscope, and a photograph thereof is shown in FIG.
[0039]
[Example 3]
Polymer particles were obtained in the same manner as in Example 2 except that a polyamide 12-6 copolymer (Ube Industries, Ltd. 7115u, containing 12% by weight of polyamide) was used. It was dumbbell-shaped particles, the particle length was 2.3 μm, the coefficient of variation was 10%, and L / d was 4.4. The specific surface area was 5.6 m ² / g.
[0040]
[Comparative Example 1]
Polyamide 6 (Ube Industries, Ltd. 1030B, molecular weight 13,000) was adjusted to a concentration of 2% by weight m-cresol solution 14 weights, 72 parts by weight of methanol and 14 parts by weight of water were added and stirred to obtain a uniform solution. . The polymer precipitated after 1 hour was filtered. When the obtained polymer was observed with a scanning electron microscope, the particle diameter was spherical particles of 8.4 μm. The specific surface area was 10.6 m ² / g.
[0041]
[Comparative Example 2]
Example 1 was repeated except that 40 parts by weight of a 2% by weight cresol solution of polyamide 12 was changed to 40 parts by weight of 1-propanol and 20 parts by weight of water. The obtained precipitate was a lump in which amorphous particles were aggregated.
[0042]
[Comparative Example 3]
The same procedure as in Example 1 was conducted except that 33 parts by weight of 1-propanol was added to 67 parts by weight of a 2% by weight cresol solution of polyamide 12 and no water was added. The solution became homogeneous, but polyamide did not precipitate even after 2 days.
[0043]
【The invention's effect】
The polyamide particles of the present invention are particles having a specific shape, a specific particle length and particle size, a narrow particle size distribution, and uniform and excellent dispersibility.
[Brief description of the drawings]
FIG. 1 is a scanning electron micrograph of polyamide particles obtained in Example 1 of the present invention.
FIG. 2 is a scanning electron micrograph of polyamide particles obtained in Example 2 of the present invention.

Claims (5)

A polyamide synthesized from 50 to 100% by weight of an amide-forming monomer (A) having 9 to 22 carbon atoms and 0 to 50% by weight of an amide-forming monomer (B) having 2 to 8 carbon atoms,
It has an elliptical shape, a cylindrical shape, a dumbbell shape, or a drum shape, a particle length of 0.5 to 25 μm, an L / D (particle length / particle diameter) of 3 to 50, and a specific surface area of 0.1 to Polyamide particles characterized by being 10 m ² / g. 2. The polyamide particle according to claim 1, comprising an aliphatic polyamide . The polyamide particles are mixed with a polyamide solution 50 to 95% by weight comprising a polyamide and a solvent and a polyamide non-solution 5 to 50% by weight containing water and a non-solvent to produce a uniform solution. 3. The polyamide particles according to claim 1, wherein the polyamide particles are precipitated at a solution temperature of 5 to 60 ° C. for 1 minute to 48 hours after production. 50 to 95 wt% of a polyamide solution comprising a polyamide synthesized from 50 to 100 wt% of an amide forming monomer (A) having 9 to 22 carbon atoms and 0 to 50 wt% of an amide forming monomer (B) having 2 to 8 carbon atoms % And 5 to 50% by weight of a polyamide non-solution containing water and a non-solvent to produce a uniform solution. After the production of the uniform solution, the solution temperature is 5 to 60 ° C. for 1 minute to 48 hours. Among them, it has an elliptical shape, a cylindrical shape, a dumbbell shape or a drum shape, a particle length of 0.5 to 25 μm, an L / D (particle length / particle diameter) of 3 to 50, and a specific surface area of 0. .1-10m ² / G of polyamide particles are precipitated, a method for producing polyamide particles. The production method according to claim 4, wherein the produced polyamide particles comprise an aliphatic polyamide.

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