JPH0323096B2 - - Google Patents
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- Publication number
- JPH0323096B2 JPH0323096B2 JP13223286A JP13223286A JPH0323096B2 JP H0323096 B2 JPH0323096 B2 JP H0323096B2 JP 13223286 A JP13223286 A JP 13223286A JP 13223286 A JP13223286 A JP 13223286A JP H0323096 B2 JPH0323096 B2 JP H0323096B2
- Authority
- JP
- Japan
- Prior art keywords
- copolymer
- methylolacrylamide
- temperature
- reaction
- thermoreversible
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Processes Of Treating Macromolecular Substances (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
Description
産業上の利用分野
本発明は、熱可逆的特性を有するアクリル系共
重合体の架橋成形体の製造方法に関するものであ
る。さらに詳しくいえば、本発明は水中において
所定温度以上に加熱すると白濁するが、それ以下
では透明化するという熱可逆特性を有し、しかも
水に不溶性で原形状を保持しうる成形体であつ
て、温室、シヨーウインドウなどの遮光体、吸着
材、玩具、水呼吸体、被覆材、分離膜、メカノケ
ミカル材料などとして広く利用することができる
新規な材料の製造方法に関するものである。
従来の技術
水溶液としたときに、所定の温度（転移温度又
は曇点）以上では析出して白濁状となりその温度
以下では溶解して透明化する水溶性高分子化合物
は、通常熱可逆高分子と称され、その可逆性を利
用して遮光体や吸着剤などへの応用がはかられて
いる。
これまで、アクリル系の熱可逆高分子として、
Ｎ−アルキル置換−アクリルアミド又はメタクリ
ルアミドの重合体が知られている。しかし、この
アクリル系熱可逆高分子は、所要の形状に成形し
ても、低温下では水に溶解し、その形状を保つこ
とができないため、おのずから用途が制限される
のを免れない。
アクリル系重合体以外にも、多くの熱可逆高分
子が提案されているが、所定の形状を維持したま
ま、高温で白濁し、低温で透明化するというもの
は知られていなかつた。
他方、Ｎ−イソプロピルアクリルアミドとＮ−
メチロールアクリルアミドとの共重合体は、拡散
転写式写真用受像紙の材料として知られているが
（米国特許第3421893号明細書）、これが熱可逆特
性を有することや、これを架橋体としうることは
全く知られていなかつた。
発明が解決しようとする問題点
本発明の目的は、熱可逆的特性を有し、しかも
水に不溶でその形状を保持しうるアクリル系高分
子架橋成形体を製造するための方法を提供するこ
とである。
問題点を解決するための手段
本発明者らは、熱可逆的特性を有し、かつ成形
したときに任意の温度においてもその形状を保持
しうる材料を開発するために、鋭意研究を重ねた
結果、Ｎ−プロピルアクリルアミドとＮ−メチロ
ールアクリルアミドから得られる共重合体を架橋
させることによりその目的を達成しうることを見
出し、この知見に基づいて本発明をなすに至つ
た。
すなわち、本発明は、一般式
（式中のR1は水素原子又はメチル基、R2はｎ
−プロピル基又はイソプロピル基である）
で表わされる化合物１モルに１モルを超えない量
のＮ−メチロールアクリルアミドを加え、溶液状
態でラジカル重合させ、得られた共重合体を成形
後、加熱して架橋させることを特徴とする熱可逆
性高分子架橋成形体の製造方法を提供するもので
ある。
本発明方法においては、一般式（）の化合物
１モル当り１モルを超えない量、好ましくは
0.002〜１モルのＮ−メチロールアクリルアミド
を用いることが必要である。この量が少ないと架
橋した場合に不溶化が不十分になるし、またこの
量が１モルを超えると水溶性高分子となるため熱
可逆的特性が示されなくなる。
本発明方法において、一般式（）の化合物と
Ｎ−メチロールアクリルアミドを共重合するに
は、単量体を均一に混合しうる溶媒を用いて行う
ことが必要である。このような溶媒の例として
は、水、アルコール、Ｎ，Ｎ−ジエチルアセトア
ミド、ジメチルスルホキシド、アセトン、ジオキ
サン、テトラヒドロフラン、ベンゼン、クロロホ
ルム、四塩化炭素などを挙げることができる。こ
れらの溶媒は単独で用いてもよいし、また２種以
上組み合わせて用いてもよい。
本発明方法においては、これらの溶媒中に、単
量体を１〜100重量％の濃度で溶解し、溶液状態
でラジカル重合させる。このラジカル重合は、通
常のラジカル重合開始剤例えばアゾビスイソブチ
ロニトリル、過酸化ベンゾイル、過酢酸などの存
在下で加熱してもよいし、また放射線や光照射に
よつて行つてもよい。
この共重合体は、成形体に加工するのに適した
分子量を有するように、例えばクロロホルム又は
メタノール溶液中、30℃における極限粘度〔η〕
が0.01〜6.0程度、特に0.1〜3.0の範囲に製造する
のが好ましい。
次に、このようにして得た共重合体を、慣用の
方法例えばキヤスト法、湿式紡糸法などによつて
成形したのち、乾式加熱することによつて、非水
溶性の成形体とする。この際の架橋化条件は、共
重合体の組成、使用する反応温度や反応時間に左
右されるが、一般的に、Ｎ−メチロールアクリル
アミド単位が多いものは、反応温度が低くなり、
また反応時間が短かくなるし、Ｎ−メチロールア
クリルアミド単位が少ないものは、反応温度が高
くなり、反応時間が長くなる。通常は、反応温度
は100〜200℃、反応時間は１〜500分の範囲内で
ある。
前記共重合体の転移温度は、各単量体単位のモ
ル比に依存し、Ｎ−メチロールアクリルアミドの
割合の増加とともに高温側に移動する。したがつ
て、このモル比を変えることによつて転移温度を
任意に調節することができる。
一方、この共重合体の熱応答感度は、Ｎ−メチ
ロールアクリルアミドの割合が増加するとともに
低下するが、この低下の割合は小さいので、全体
的に熱応答感度は良好である。
実施例
次に実施例により本発明をさらに詳細に説明す
る。
実施例 １
Ｎ−メチロールアクリルアミド及びＮ−イソプ
ロピルアクリルアミドの組合せ仕込量を変えて
種々の組成比の共重合体を製造した。重合開始剤
としてアゾビスイソブチロニトリルを用い、その
濃度５mg／mlメタノール溶液20mlを所定の組成及
び濃度のモノマー溶液に投入、反応温度50℃で14
時間反応させた。反応後、反応溶液をアセトン溶
液とし、ジエチルエーテルに沈殿させ、ポリマー
を回収した。共重合体中のＮ−メチロールアクリ
ルアミド分率は、重合率100％と仮定して算出し
た。得られた熱可逆高分子の転移温度は、その水
溶液の温度に伴う光透過率変化から決定した。す
なわち、１％濃度のポリマー水溶液を調整して、
温度コントロール付分光光度計にセツトし、昇温
速度１℃／minで昇温させながら波長500nmでの
光透過率変化を測定すると第１図のごとき結果が
得られる。
転移温度は、この図で、光透過率が初期透過率
の1/2となる点から決定した。
各実験におけるモノマー仕込量、共重合体中の
Ｎ−メチロールアクリルアミド分率、転移温度を
第１表にまとめて示す。
INDUSTRIAL APPLICATION FIELD The present invention relates to a method for producing a crosslinked molded article of an acrylic copolymer having thermoreversible properties. More specifically, the present invention is a molded article that has thermoreversible properties such that it becomes cloudy when heated above a predetermined temperature in water, but becomes transparent when heated below that temperature, and is insoluble in water and capable of retaining its original shape. The present invention relates to a method for producing a novel material that can be widely used as a light shielding material for greenhouses, show windows, etc., adsorbent materials, toys, water-breathing materials, coating materials, separation membranes, mechanochemical materials, and the like. Prior Art Water-soluble polymer compounds that, when made into an aqueous solution, precipitate and become cloudy at temperatures above a certain temperature (transition temperature or cloud point) and dissolve and become transparent below that temperature are usually called thermoreversible polymers. Its reversibility is being used to find applications in light shielding materials, adsorbents, etc. Until now, as an acrylic thermoreversible polymer,
Polymers of N-alkyl substituted acrylamide or methacrylamide are known. However, even if this acrylic thermoreversible polymer is molded into a desired shape, it dissolves in water at low temperatures and cannot maintain its shape, so its uses are naturally limited. Many thermoreversible polymers other than acrylic polymers have been proposed, but none are known to become cloudy at high temperatures and transparent at low temperatures while maintaining a predetermined shape. On the other hand, N-isopropylacrylamide and N-
A copolymer with methylol acrylamide is known as a material for diffusion transfer photographic image receiving paper (US Pat. No. 3,421,893), but it is known that it has thermoreversible properties and that it can be used as a crosslinked product. was completely unknown. Problems to be Solved by the Invention An object of the present invention is to provide a method for producing an acrylic polymer crosslinked molded product that has thermoreversible properties, is insoluble in water, and can retain its shape. It is. Means for Solving the Problems The present inventors have conducted extensive research in order to develop a material that has thermoreversible properties and can maintain its shape at any temperature when molded. As a result, the inventors discovered that the objective could be achieved by crosslinking a copolymer obtained from N-propylacrylamide and N-methylolacrylamide, and based on this knowledge, the present invention was accomplished. That is, the present invention provides the general formula (R 1 in the formula is a hydrogen atom or a methyl group, R 2 is n
-Propyl group or isopropyl group) N-methylol acrylamide in an amount not exceeding 1 mole is added to 1 mole of the compound represented by the formula (propyl group or isopropyl group), radical polymerization is carried out in a solution state, and the resulting copolymer is molded and then heated. The present invention provides a method for producing a thermoreversible polymer crosslinked molded article, which is characterized by crosslinking. In the process of the invention, an amount not exceeding 1 mole per mole of compound of general formula (), preferably
It is necessary to use 0.002 to 1 mol of N-methylolacrylamide. If this amount is small, insolubilization will be insufficient when crosslinked, and if this amount exceeds 1 mol, the polymer will become water-soluble and will not exhibit thermoreversible properties. In the method of the present invention, in order to copolymerize the compound of general formula () and N-methylolacrylamide, it is necessary to use a solvent that can uniformly mix the monomers. Examples of such solvents include water, alcohol, N,N-diethylacetamide, dimethyl sulfoxide, acetone, dioxane, tetrahydrofuran, benzene, chloroform, carbon tetrachloride, and the like. These solvents may be used alone or in combination of two or more. In the method of the present invention, monomers are dissolved in these solvents at a concentration of 1 to 100% by weight, and radical polymerization is carried out in a solution state. This radical polymerization may be carried out by heating in the presence of a conventional radical polymerization initiator such as azobisisobutyronitrile, benzoyl peroxide, peracetic acid, etc., or by radiation or light irradiation. This copolymer has an intrinsic viscosity [η] at 30°C in a chloroform or methanol solution, for example, so that it has a molecular weight suitable for processing into a molded body.
is preferably in the range of about 0.01 to 6.0, particularly 0.1 to 3.0. Next, the copolymer thus obtained is molded by a conventional method such as a casting method or a wet spinning method, and then dry heated to form a water-insoluble molded product. The crosslinking conditions at this time depend on the composition of the copolymer, the reaction temperature and reaction time used, but in general, the more N-methylolacrylamide units there are, the lower the reaction temperature will be.
Furthermore, the reaction time becomes shorter, and those containing fewer N-methylolacrylamide units require a higher reaction temperature and longer reaction time. Usually, the reaction temperature is in the range of 100 to 200°C and the reaction time is in the range of 1 to 500 minutes. The transition temperature of the copolymer depends on the molar ratio of each monomer unit, and shifts toward higher temperatures as the proportion of N-methylolacrylamide increases. Therefore, by changing this molar ratio, the transition temperature can be adjusted as desired. On the other hand, the thermal response sensitivity of this copolymer decreases as the proportion of N-methylolacrylamide increases, but the rate of this decrease is small, so the thermal response sensitivity is good overall. Examples Next, the present invention will be explained in more detail with reference to Examples. Example 1 Copolymers having various composition ratios were produced by changing the combined amounts of N-methylolacrylamide and N-isopropylacrylamide. Using azobisisobutyronitrile as a polymerization initiator, 20 ml of a methanol solution with a concentration of 5 mg/ml was added to a monomer solution with a predetermined composition and concentration, and the reaction temperature was 50°C for 14 min.
Allowed time to react. After the reaction, the reaction solution was made into an acetone solution, precipitated in diethyl ether, and the polymer was recovered. The N-methylolacrylamide fraction in the copolymer was calculated assuming a polymerization rate of 100%. The transition temperature of the obtained thermoreversible polymer was determined from the change in light transmittance with the temperature of its aqueous solution. That is, by preparing a 1% concentration polymer aqueous solution,
When set in a spectrophotometer with temperature control and measuring the change in light transmittance at a wavelength of 500 nm while increasing the temperature at a rate of 1°C/min, the results shown in Figure 1 are obtained. The transition temperature was determined from the point in this figure where the light transmittance is 1/2 of the initial transmittance. Table 1 summarizes the amount of monomer charged, the N-methylolacrylamide fraction in the copolymer, and the transition temperature in each experiment.
【表】
これらの結果より得られた共重合体は熱応答感
度がすぐれ、かつ共重合体中のＮ−メチロールア
クリルアミドの含有量により広範囲に転移温度を
変化させうることが分つた。
また、実験No.３の試料をフイルム状に成形し、
150℃で１時間乾式加熱したところ、加熱前の形
状のままの架橋体が得られた。
実施例 ２
Ｎ−メチロールアクリルアミド及びＮ−ｎ−プ
ロピルアクリルアミドの組合せ仕込量を変えて
種々の組成比の共重合体を製造した。重合開始剤
としてアゾビスイソブチロニトリルを用い、その
濃度５mg／mlのメタノール溶液25mlを所定の組成
及び濃度のモノマー溶液に投入、反応濃度50℃で
40時間反応させた。反応後、メタノール溶液と
し、ジエチルエーテルに沈殿させポリマーを回収
した。共重合体中のＮ−メチロールアクリルアミ
ド分率は、重合率100％と仮定して算出した。転
移温度は実施例１の方法で求めた。
各実験におけるモノマー仕込量、共重合体中の
Ｎ−メチロールアクリルアミド分率・転移温度の
関係を第２表にまとめて示す。[Table] From these results, it was found that the copolymer obtained had excellent thermal response sensitivity, and the transition temperature could be varied over a wide range depending on the content of N-methylolacrylamide in the copolymer. In addition, the sample from Experiment No. 3 was formed into a film,
When dry heating was performed at 150° C. for 1 hour, a crosslinked product was obtained that remained in the same shape as before heating. Example 2 Copolymers having various composition ratios were produced by changing the combined amounts of N-methylolacrylamide and N-n-propylacrylamide. Using azobisisobutyronitrile as a polymerization initiator, 25 ml of a methanol solution with a concentration of 5 mg/ml was added to a monomer solution with a predetermined composition and concentration, and the reaction concentration was 50°C.
The reaction was allowed to proceed for 40 hours. After the reaction, it was made into a methanol solution and precipitated in diethyl ether to recover the polymer. The N-methylolacrylamide fraction in the copolymer was calculated assuming a polymerization rate of 100%. The transition temperature was determined by the method of Example 1. Table 2 summarizes the relationship between the amount of monomer charged, the N-methylolacrylamide fraction in the copolymer, and the transition temperature in each experiment.
【表】
これらの結果より、実施例１と同様に共重合体
中のＮ−メチロールアクリルアミド含有量により
広範囲に転移温度を変化させうることが分つた。
また、実験No.15の試料をフイルム状に成形し、
150℃で１時間乾式加熱したところ、加熱前の形
状を保ち架橋した。
実施例 ３
Ｎ−メチロールアクリルアミド及びＮ−イソプ
ロピルメタクリルアミドの組合せ仕込量を変えて
種々の組成比の共重合体を製造した。重合開始剤
としてアゾビスイソブチロニトリルを用い、その
濃度５mg／mlのメタノール溶液20mlを所定の組
成、濃度のモノマー溶液に投入し、反応温度50℃
で70時間反応させた。反応後メタノール溶液をア
セトン溶液とし、ジエチルエーテルに沈殿させポ
リマーを回収した。共重合体中のＮ−メチロール
アクリルアミド分率は重合率100％と仮定して算
出した。転移温度は、実施例１の方法で求めた。
各実験におけるモノマー仕込量、共重合体中の
Ｎ−メチロールアクリルアミド分率、転移温度の
関係を第３表にまとめて示す。[Table] From these results, as in Example 1, it was found that the transition temperature could be varied over a wide range depending on the N-methylolacrylamide content in the copolymer. In addition, the sample from Experiment No. 15 was molded into a film,
When it was dry-heated at 150°C for 1 hour, it maintained its shape before heating and was crosslinked. Example 3 Copolymers having various composition ratios were produced by changing the combined amounts of N-methylolacrylamide and N-isopropylmethacrylamide. Using azobisisobutyronitrile as a polymerization initiator, 20 ml of a methanol solution with a concentration of 5 mg/ml was added to a monomer solution with a predetermined composition and concentration, and the reaction temperature was 50°C.
The reaction was carried out for 70 hours. After the reaction, the methanol solution was made into an acetone solution, and the polymer was recovered by precipitation in diethyl ether. The N-methylolacrylamide fraction in the copolymer was calculated assuming a polymerization rate of 100%. The transition temperature was determined by the method of Example 1. Table 3 summarizes the relationship among the amount of monomer charged, the N-methylolacrylamide fraction in the copolymer, and the transition temperature in each experiment.
【表】
これらの結果より、実施例１と同様に共重合体
のＮ−メチロールアクリルアミドの含有量により
広範囲に転移温度を変化させうることが分つた。
また、実験No.21の試料をフイルム状に成形し、
150℃で１時間加熱したところ、加熱前の形状を
保ち架橋した。
実施例 ４
Ｎ−メチロールアクリルアミド1.30ｇ、Ｎ−イ
ソプロピルアクリルアミド12.07ｇ、アゾビスイ
ソブチロニトリルを含むメタノール溶液（濃度５
mg／ml）100mlをアンプルに入れ、液体ちつ素を
用いて減圧脱気を行い、上部をバーナーで封じ
た。これを50℃の恒温槽に入れ、24時間放置し重
合させた。反応後、開封しメタノールを減圧除去
した。さらにこれをアセトン溶液としジエチルエ
ーテル中に沈殿させポリマーを回収した。共重合
体中のＮ−メチロールアクリルアミド分率は、
10.7％であつた。この共重合体１％水溶液の転移
温度は、36.0℃であつた。また、この共重合体の
極限粘度は、クロロホルム溶液として30℃での粘
度測定より〔η〕＝0.48であつた。
この共重合体をアセトンに溶かし、テフロン板
上に流して風乾し、フイルムを作成した。このフ
イルム状成形体を乾式加熱処理した時の処理条件
と架橋状態との関係を第４表に示す。[Table] From these results, as in Example 1, it was found that the transition temperature could be varied over a wide range depending on the content of N-methylolacrylamide in the copolymer. In addition, the sample from Experiment No. 21 was molded into a film,
When heated at 150°C for 1 hour, the shape before heating was maintained and crosslinked. Example 4 A methanol solution containing 1.30 g of N-methylolacrylamide, 12.07 g of N-isopropylacrylamide, and azobisisobutyronitrile (concentration 5
mg/ml) was placed in an ampoule, degassed under reduced pressure using liquid nitrogen, and the upper part was sealed with a burner. This was placed in a constant temperature bath at 50°C and left to polymerize for 24 hours. After the reaction, the container was opened and methanol was removed under reduced pressure. Furthermore, this was made into an acetone solution and precipitated in diethyl ether to recover the polymer. The N-methylolacrylamide fraction in the copolymer is
It was 10.7%. The transition temperature of this 1% aqueous copolymer solution was 36.0°C. Further, the intrinsic viscosity of this copolymer was determined to be [η]=0.48 by viscosity measurement at 30°C as a chloroform solution. This copolymer was dissolved in acetone, poured onto a Teflon plate, and air-dried to produce a film. Table 4 shows the relationship between the treatment conditions and the crosslinking state when this film-like molded product was subjected to dry heat treatment.
【表】
×：水に溶解（未架橋）
○：水に未溶解（架橋）
第４表から明らかなようにフイルム状成形体を
乾式加熱処理することにより、容易に架橋成形体
とすることができる。
発明の効果
本発明方法により得られる熱可逆性高分子架橋
成形体は、水中において所定の温度以上では白濁
し、それ以下では透明になる熱可逆的特性を有
し、しかも非水溶性で成形したときの形状をその
まま保持しうるので、メカノケミカル材料、遮光
材、吸着剤、玩具素材、分離膜などとして広く利
用することができる。[Table] ×: Dissolved in water (uncrosslinked)
○: Not dissolved in water (crosslinked)
As is clear from Table 4, a film-like molded product can be easily made into a crosslinked molded product by subjecting it to dry heat treatment. Effects of the Invention The thermoreversible polymer crosslinked molded product obtained by the method of the present invention has a thermoreversible property of becoming cloudy in water above a predetermined temperature and becoming transparent below a certain temperature, and is non-water soluble. Since it can maintain its original shape, it can be widely used as mechanochemical materials, light shielding materials, adsorbents, toy materials, separation membranes, etc.
第１図はＮ−イソプロピルアクリルアミドとＮ
−メチロールアクリルアミドの共重合体、第２図
はＮ−ｎ−プロピルアクリルアミドとＮ−メチロ
ールアクリルアミドの共重合体の水溶液の光透過
率と温度の関係を示すグラフである。
Figure 1 shows N-isopropylacrylamide and N
- Copolymer of methylolacrylamide. FIG. 2 is a graph showing the relationship between the light transmittance and temperature of an aqueous solution of a copolymer of N-n-propylacrylamide and N-methylolacrylamide.
Claims (1)
−プロピル基又はイソプロピル基である） で表わされる化合物１モルに１モルを超えない量
のＮ−メチロールアクリルアミドを加え、溶液状
態でラジカル重合させ、得られた共重合体を成形
後、加熱して架橋させることを特徴とする熱可逆
性高分子架橋成形体の製造方法。[Claims] 1. General formula (R 1 in the formula is a hydrogen atom or a methyl group, R 2 is n
-Propyl group or isopropyl group) N-methylol acrylamide in an amount not exceeding 1 mole is added to 1 mole of the compound represented by the formula (propyl group or isopropyl group), radical polymerization is carried out in a solution state, and the resulting copolymer is molded and then heated. A method for producing a thermoreversible polymer crosslinked molded article, which comprises crosslinking.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13223286A JPS61287931A (en) | 1986-06-07 | 1986-06-07 | Production of thermoreversible high-molecular crosslinked molding |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13223286A JPS61287931A (en) | 1986-06-07 | 1986-06-07 | Production of thermoreversible high-molecular crosslinked molding |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18859784A Division JPS6166707A (en) | 1984-09-08 | 1984-09-08 | Production of crosslinkable, thermally reversible high polymer compound |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61287931A JPS61287931A (en) | 1986-12-18 |
| JPH0323096B2 true JPH0323096B2 (en) | 1991-03-28 |
Family
ID=15076458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13223286A Granted JPS61287931A (en) | 1986-06-07 | 1986-06-07 | Production of thermoreversible high-molecular crosslinked molding |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61287931A (en) |
-
1986
- 1986-06-07 JP JP13223286A patent/JPS61287931A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61287931A (en) | 1986-12-18 |
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