【発明の詳細な説明】[Detailed description of the invention]
本発明はキトサン又はキトサン酸塩を出発原料
として新規なキトサン繊維の製造方法に関するも
のである。更に詳しくは、本発明は湿式成形によ
りキトサン繊維の製造する際、キトサン又はキト
サン酸塩から繊維を紡出する紡出原液を製造する
ための薬品及び該原液を凝固成形させる溶媒に特
定の組成のものを使用することにより、高品質の
キトサン繊維の製造する方法に関する。
キトサンはエビ、カニ等の甲殻類、バツタ、カ
ブトムシ等の昆虫類等に含まれ自然界に広く分布
し存在しているＮ−アセチル−Ｄ−グルコサミン
β−1.4−グルコシド結合した多糖類のキチンを
濃苛性アルカリで熱処理し、アセチル基を加水分
解し脱アセチル化キチンとしてものであることは
知られている。そして、キトサンは水や低分子物
質を透過する性質を具備し、抗凝血性にも勝れて
生体組織との親和性も良好であり組織反応を生ぜ
ず、バイオマテリアルとしての性能があり、マイ
クロカプセル材料、透析膜、人造臓器、手術用材
料、血管補綴材等への応用が計られている。従
来、キトサンを出発原料として成形用溶液とする
のにキトサンを酢酸水溶液に溶解して原液とし、
アルコールと水と混合凝固浴中に紡出し繊維に成
形する方法が特開昭56−26049に記載されている
が、キトサンを酢酸水溶液に溶解させた時、キト
サン分子間の水素結合が強固であるために該原液
の粘度が極端に高くなり紡糸の際の可紡性に欠点
として現れ、又水／メタノール混合溶媒の凝固浴
中では凝固再生させるのにかなりの時間を必要と
し、凝固浴槽を長くしなければならない欠点があ
る。この諸欠点を改善するために本発明者等は特
開昭59−116418号公報特願昭57−232464）でキト
サンを水−ジクロル酢酸混合液に溶解して原液と
し、キトサン酸塩を原料とする時は水又は水−ジ
クロル酢酸混合溶液で溶解し原液とし、諸原液を
金属塩水溶液中で凝固成形させ、その後キレート
試薬を用いて処理する方法を提案し、原液の曵糸
性及び凝固促進等の改善を計つた。
しかし、上述の薬品の中には皮膚に対する刺戟
性が強く、実技的に取扱いの上で危険性を伴うも
のがあるため、本薬品と同一又は更に効果があり
安全性の高い薬品を選択使用することについて鋭
意検討の結果、キトサン又はキトサン酸塩を酢酸
水溶液と尿素の混合液中に溶解させることにより
良好な曵糸性を具備した紡出に適した粘度の原液
が得られることを見出した。
一方、キトサン繊維の製造において、凝固浴と
して塩基性物質を含む水溶液を用いることは、特
開昭56−106901に開示されているが、本発明の方
法により得た紡糸原液を塩基性物質のみを含む凝
固浴を用いて紡出すると凝固浴中での凝固速度が
早過ぎ、成形される繊維表面に於ける凝固のみが
進行してしまい、内部に於ける原液の凝固再生が
遅れてマイブレーシヨンを起し、キトサン原液溶
媒が表面に浸出し、折角紡出した単繊維の合着を
生じ易い欠点がある。本発明においてはかかる欠
点を解決するため、凝固浴中にアルコールを添加
し、アルコールの凝固に対する緩衝効果により、
繊維全体に均一な凝固速度を生じさせ得ることを
見出した。また、アルコールの添加により、次工
程である洗浄工程でも過剰の塩基性物質の除去が
容易となる利点もある。
上記のように、本発明はキトサン又はキトサン
酸塩を酢酸水溶液と尿素の混合溶液に溶解して紡
糸原液とし、該原液を塩基性水溶液とアルコール
の混合液中で成形してキトサン繊維の製造するも
のである。
キトサンはキチンを濃厚アルカリで熱処理し、
脱アセチル化した白色無定形粉末で、キトサン酸
塩としては、例えばキトサン酢酸塩はキトサンを
希酢酸に溶解し、イソプロピルアルコールで沈澱
させて水洗、乾燥して得られる白色無定形粉末で
あり、その他、酢酸以外の蟻酸等の有機酸や鉱酸
からも同様の処理を行つて得ることができる。キ
トサン及びキトサン酸塩は酢酸水溶液と尿素の混
合溶液に溶解する。尿素を全く添加しない場合
は、キトサンを溶解した酢酸水溶液は、キトサン
濃度が３重量％程度であつても通常はゲル化状態
であり、紡出が困難である。尿素を添加すること
により紡出液の粘度を低下せしめ、良好な紡出液
とすることができるが尿素の添加量は必要以上に
増加せしめても、その効果はあまり顕著ではな
い。また、酢酸水溶液の濃度が増加する時には凝
固浴の塩基性水溶液濃度を高くする必要があるの
で、あまり高くすることは好ましくない。酢酸と
尿素は、それぞれ混合水溶液中の濃度が0.5〜20
重量％と0.1〜10重量％、好ましくは１〜10重量
％と0.1〜５重量％となるような範囲で適宜組合
せ使用する。
上記のようにして調製された紡糸原液は塩基性
水溶液とアルコールの混合液中に紡糸される。塩
基性物質としては、NaOH，KOH，NH4OH，
NaHCO3等のアルカリ性物質が用いられ、アルコ
ールとしてはCH3OH，C2H5OH等が好ましく、
塩基性物質を分離してしまう性質のある、例えば
イソプロピルアルコール等が除去されることは言
うまでもない。塩基性水溶液の濃度は１〜50重量
％、好ましくは１〜20重量％であり、塩基性水溶
液とアルコールの混合比率は、容量比で塩基性水
溶液／アルコールが95/5〜30/70、好ましくは95/
５〜50/50である。
本発明によれば、作業環境が良好であり、紡糸
に要する時間も比較的短く、得られる繊維は充分
な強度を有する良好なものであつて、各方面に利
用可能である。尚、上記記載は繊維についてなさ
れているが、同様にして良好なフイルム、その他
の成形物が得られることは勿論である。
以下、本発明を実施例を挙げて説明するが、本
発明はこれらの範囲に限定されるものではない。
尚、実施例中に記載の％は、特に規定しない限
り重量％を示すものとする。
実施例 １
紅ずわいガニの外殻から得られた30〜40メツシ
ユ粒のキトサンを５〜酢酸水溶液と尿素１％を含
む混合溶液に撹拌溶解し、過脱泡を行つて濃度
3.5％、粘度152ポイズの原液を得た。この原液を
NaOH濃度５％、10％、20％の３水準で、NaOH
水溶液／エタノール混合比率（Vo／Vo）を9
０／１０，70/30，50/50，30/70，10/90と変更して調
製した常温の夫々の紡浴中に0.14m/m×180Hノズ
ルを用い押出し、1mの凝固浴中で繊維形成さ
せ、温水で後処理し1.25倍の延伸倍率で捲き取
り、緊張状態のまま80℃で30分乾燥させた。
夫々の得られた繊維につき糸試験を行つた結果
を第１表に示した。第１表から明かな如く同一原
液では凝固浴中のNaOH水溶液／エタノール混合
比率が50/50より10/90の如く変ると紡糸困難であ
ることが明かで、それ以外の条件で得られた繊維
の糸質は夫々良質なものであつた。
表中の紡糸状態を示す◎，〇，△，×印は、紡
糸の容易性、状態を夫々優、良、可、不可の４段
階として示したものであり、以下の各表において
も同様である。
The present invention relates to a novel method for producing chitosan fibers using chitosan or chitosanate as a starting material. More specifically, when producing chitosan fibers by wet molding, the present invention provides chemicals for producing a spinning stock solution for spinning fibers from chitosan or chitosanate salts, and a solvent with a specific composition for coagulating and molding the stock solution. This invention relates to a method for producing high quality chitosan fibers by using Chitosan is a concentrated form of chitin, a polysaccharide with N-acetyl-D-glucosamine β-1.4-glucosidic bonds that is widely distributed in nature and is found in crustaceans such as shrimp and crabs, and insects such as grasshoppers and rhinoceros beetles. It is known that chitin can be heat-treated with caustic alkali to hydrolyze the acetyl groups, resulting in deacetylated chitin. Chitosan has the property of permeating water and low-molecular substances, has excellent anticoagulant properties, has good affinity with living tissues, does not cause tissue reactions, and has the performance as a biomaterial. Applications are being planned for capsule materials, dialysis membranes, artificial organs, surgical materials, vascular prosthesis materials, etc. Conventionally, to make a molding solution using chitosan as a starting material, chitosan was dissolved in an acetic acid aqueous solution to make a stock solution.
A method of forming fibers by spinning them into a coagulating bath mixed with alcohol and water is described in JP-A-56-26049, but when chitosan is dissolved in an acetic acid aqueous solution, the hydrogen bonds between chitosan molecules are strong. Therefore, the viscosity of the stock solution becomes extremely high, which appears as a drawback in spinnability during spinning, and in a water/methanol mixed solvent coagulation bath, a considerable amount of time is required for coagulation and regeneration, and the coagulation bath is not used for a long time. There are drawbacks that must be met. In order to improve these drawbacks, the inventors of the present invention dissolved chitosan in a water-dichloroacetic acid mixture to obtain a stock solution, and used chitosanate as a raw material in Japanese Patent Application Laid-open No. 59-116418 (Japanese Patent Application No. 57-232464). In order to improve the spinnability and coagulation of the stock solution, we propose a method in which the stock solution is dissolved in water or a mixed solution of water and dichloroacetic acid, and the stock solution is coagulated and formed in an aqueous metal salt solution, and then treated with a chelating reagent. Improvements were made. However, some of the above-mentioned drugs are highly irritating to the skin and may be dangerous to handle in practice, so it is recommended to select and use a drug that is the same or more effective and safer than this drug. As a result of extensive studies, it was discovered that by dissolving chitosan or chitosanate in a mixed solution of acetic acid and urea, a stock solution with good spinnability and a viscosity suitable for spinning could be obtained. On the other hand, in the production of chitosan fibers, the use of an aqueous solution containing a basic substance as a coagulation bath is disclosed in JP-A-56-106901. If spinning is performed using a coagulation bath containing 100% of the raw material, the coagulation speed in the coagulation bath will be too fast, and coagulation will proceed only on the surface of the fiber to be formed, and the coagulation and regeneration of the raw solution inside will be delayed, resulting in migration. This has the disadvantage that the solvent of the chitosan stock solution leaches out onto the surface, which tends to cause coalescence of the single fibers that have been carefully spun. In the present invention, in order to solve this drawback, alcohol is added to the coagulation bath, and due to the buffering effect of alcohol on coagulation,
It has been found that uniform coagulation rates can be produced throughout the fiber. Furthermore, the addition of alcohol has the advantage that excess basic substances can be easily removed in the next washing step. As described above, the present invention involves dissolving chitosan or chitosanate in a mixed solution of aqueous acetic acid and urea to obtain a spinning stock solution, and molding the stock solution in a mixed solution of a basic aqueous solution and alcohol to produce chitosan fibers. It is something. Chitosan is made by heat-treating chitin with concentrated alkali.
A deacetylated white amorphous powder. Chitosanate salts include, for example, chitosan acetate, which is a white amorphous powder obtained by dissolving chitosan in dilute acetic acid, precipitating it with isopropyl alcohol, washing with water, and drying. It can also be obtained from organic acids such as formic acid and mineral acids other than acetic acid by the same treatment. Chitosan and chitosanate are dissolved in a mixed solution of acetic acid aqueous solution and urea. When no urea is added, the acetic acid aqueous solution in which chitosan is dissolved is usually in a gelled state even if the chitosan concentration is about 3% by weight, making spinning difficult. By adding urea, the viscosity of the spinning solution can be lowered and a good spinning solution can be obtained, but even if the amount of urea added is increased more than necessary, the effect is not so significant. Furthermore, when the concentration of the acetic acid aqueous solution increases, it is necessary to increase the concentration of the basic aqueous solution in the coagulation bath, so it is not preferable to increase the concentration too much. Acetic acid and urea each have a concentration of 0.5 to 20 in the mixed aqueous solution.
They are used in appropriate combinations within the range of 0.1 to 10% by weight, preferably 1 to 10% by weight and 0.1 to 5% by weight. The spinning stock solution prepared as described above is spun into a mixture of a basic aqueous solution and alcohol. Basic substances include NaOH, KOH, NH 4 OH,
An alkaline substance such as NaHCO 3 is used, and the alcohol is preferably CH 3 OH, C 2 H 5 OH, etc.
Needless to say, substances such as isopropyl alcohol, which have the property of separating basic substances, are removed. The concentration of the basic aqueous solution is 1 to 50% by weight, preferably 1 to 20% by weight, and the mixing ratio of the basic aqueous solution and alcohol is 95/5 to 30/70 by volume, preferably 30/70 (basic aqueous solution/alcohol). is 95/
5 to 50/50. According to the present invention, the working environment is favorable, the time required for spinning is relatively short, and the obtained fibers are good and have sufficient strength, and can be used in various fields. Although the above description has been made regarding fibers, it goes without saying that good films and other molded products can be obtained in the same manner. The present invention will be described below with reference to Examples, but the present invention is not limited to these scopes. Incidentally, the percentages described in the examples indicate weight percentages unless otherwise specified. Example 1 Thirty to forty mesh pieces of chitosan obtained from the outer shell of red snow crab were stirred and dissolved in a mixed solution containing an aqueous solution of five to acetic acid and 1% urea, and the concentration was determined by excessive defoaming.
A stock solution of 3.5% and viscosity of 152 poise was obtained. This stock solution
At three levels of NaOH concentration: 5%, 10%, and 20%, NaOH
Aqueous solution/ethanol mixing ratio (Vo/Vo) is 9
0/10, 70/30, 50/50, 30/70, and 10/90 were extruded into the respective spinning baths at room temperature using a 0.14 m/m x 180 H nozzle, and into a 1 m coagulation bath. The fibers were formed, post-treated with hot water, rolled up at a stretching ratio of 1.25 times, and dried under tension at 80° C. for 30 minutes. Table 1 shows the results of a yarn test performed on each of the obtained fibers. As is clear from Table 1, it is clear that with the same stock solution, it is difficult to spin when the NaOH aqueous solution/ethanol mixing ratio in the coagulation bath changes from 50/50 to 10/90. The quality of each thread was of good quality. The ◎, 〇, △, and × marks indicating the spinning condition in the table indicate the ease of spinning and the condition as four grades: excellent, good, fair, and poor, and the same applies to each table below. be.
【表】
実施例 ２
キトサンを５％酢酸水溶液と尿素を0.2％、１
％、５％、10％と変化させた混合溶液にそれぞれ
撹拌溶解し、過、脱泡をし、濃度3.5％の原液
を夫々調製し実施例１と同様の方法で凝固浴組成
NaOH10％水溶液／エタノールで混合比率50/50
（Vo／Vo）の凝固浴中に紡糸し繊維を得て、
夫々の得られた繊維について糸試験を行つた結果
を第２表に示した、表中の紡糸状態の判定は実施
例１、と同様で、酢酸水濃度が同一の時には尿素
の添加量による物性の差異は大きくなく良好で、
原液の粘度は尿素を添加することによつて著しく
減少し、また尿素の添加量が増えると低下する傾
向のあることが明かである。[Table] Example 2 Chitosan in 5% acetic acid aqueous solution and urea in 0.2%, 1
%, 5%, and 10%, respectively, by stirring and dissolving, filtering, and defoaming to prepare stock solutions with a concentration of 3.5%, and the coagulation bath composition was prepared in the same manner as in Example 1.
Mixing ratio 50/50 with NaOH 10% aqueous solution/ethanol
(Vo/Vo) to obtain fibers by spinning in a coagulation bath,
Table 2 shows the results of the thread test for each of the obtained fibers.The determination of the spinning state in the table is the same as in Example 1, and when the acetic acid water concentration is the same, the physical properties are determined by the amount of urea added. The difference is good and not large,
It is clear that the viscosity of the stock solution is significantly reduced by adding urea, and tends to decrease as the amount of urea added increases.
【表】
実施例 ３
キトサンをそれぞれ１％、５％、10％の酢酸水
溶液と尿素１％の混合溶液に撹拌溶解し過脱泡
を行い夫々濃度3.5％、粘度152ポイズの原液を調
製し、実施例１と同様に凝固浴としてNaOH濃度
５％、10％、20％で夫々NaOH水溶液／エタノー
ル混合比率50/50（Vo／Vo）の凝固浴中に
夫々紡出し得た繊維につき夫々繊維試験を行つた
結果を第３表に示す。この結果から酢酸水溶液の
濃度が増加した時凝固浴中のNaOHの濃度が或る
程度以上ないと凝固しにくいことが明かである。[Table] Example 3 Chitosan was stirred and dissolved in a mixed solution of 1%, 5%, and 10% acetic acid aqueous solution and 1% urea, and excessive defoaming was performed to prepare stock solutions with a concentration of 3.5% and a viscosity of 152 poise, respectively. Similarly to Example 1, fiber tests were conducted on fibers spun into coagulation baths with NaOH concentrations of 5%, 10%, and 20%, respectively, and a NaOH aqueous solution/ethanol mixing ratio of 50/50 (Vo/Vo). The results are shown in Table 3. From this result, it is clear that when the concentration of acetic acid aqueous solution increases, coagulation is difficult unless the concentration of NaOH in the coagulation bath exceeds a certain level.
【表】
実施例 ４
紅ずわいガニの外殻から得られた30〜40メツシ
ユ粒のキトサン酢酸塩を濃度１％、５％、10％の
酢酸水溶液３水準と尿素１％の混合溶液に夫々撹
拌、溶解し、過、脱泡を行つて濃度3.5％で粘
度が夫々146ポイズ、122ポイズ、110ポイズの原
液を得た。
この原液をNaOH濃度５％、10％、20％の３水
準で、NaOH水溶液／エタノール混合比率（Vo
／Vo）を50/50に調整した常温の夫々の紡浴
中に実施例１と同様に紡出し夫々繊維を得た。
夫々の得られた繊維の物性質を第４表に示した。
この結果はキトサンを原料とした実施例と同様に
良質の繊維が得られた。[Table] Example 4 30 to 40 mesh pieces of chitosan acetate obtained from the outer shell of red snow crab were added to a mixed solution of three levels of acetic acid aqueous solution with concentrations of 1%, 5%, and 10% and 1% urea, respectively. Stirring, dissolving, filtering, and defoaming were performed to obtain stock solutions with a concentration of 3.5% and viscosities of 146 poise, 122 poise, and 110 poise, respectively. This stock solution was used at three levels of NaOH concentration: 5%, 10%, and 20%, and the NaOH aqueous solution/ethanol mixing ratio (Vo
/Vo) was adjusted to 50/50 in the respective spinning baths at room temperature to obtain respective fibers by spinning in the same manner as in Example 1.
Table 4 shows the physical properties of each of the obtained fibers.
The results showed that fibers of good quality were obtained, similar to the examples using chitosan as the raw material.
【表】
実施例 ５
キトサン酢酸塩を原料とし酢酸水溶液５％と尿
素１％の混合溶液中に溶解し濃度3.5％の原液を
得て凝固浴組成としてNaOH濃度５％でNaOH水
溶液／エタノール混合比率（Vo／Vo）を90/
１０，70/30，50/50，30/70，10/90と変更し実施例
４と同様に紡出し繊維を得た。夫々の物性値を第
５表に示したが、キトサンを原料とした時と同様
にNaOH水溶液／エタノール混合比率が変ると紡
糸が困難となる。[Table] Example 5 Chitosan acetate was used as a raw material and dissolved in a mixed solution of 5% acetic acid aqueous solution and 1% urea to obtain a stock solution with a concentration of 3.5%, and the coagulation bath composition was NaOH aqueous solution/ethanol mixing ratio with NaOH concentration of 5%. (Vo／Vo)90/
Spun fibers were obtained in the same manner as in Example 4, with the changes being 10, 70/30, 50/50, 30/70, and 10/90. The respective physical properties are shown in Table 5, but as with the case when chitosan was used as a raw material, spinning became difficult if the mixing ratio of NaOH aqueous solution/ethanol was changed.
【表】【table】