Asahi Kasei Kogyo Kabushiki Kaisha

Kenji Kamide

Kunihiko Okajima

Toshihiko Matsui

Shuji Kajita

Yutaka Honda

Disclosed is an acrylic fiber composed of an acrylonitrile homopolymer or copolymer whose surface consists of particulate and/or microfibrillar structures having a width of 0.01 to 0.5 .mu.m and a length of 0.05 to 10 .mu.m and fibrillar structures formed by aggregation of the particulate and/or microfibrillar structures and having a width of 0.1 to 10 .mu.m and a length of at least 50 .mu.m. The fiber is prepared by spinning a dope of an acrylonitrile homopolymer or copolymer in a solvent at a draft ratio of at least 5 into a coagulating bath comprising a solvent and a coagulant and having a composition such that a skin layer is not formed on the coagulated fiber; taking up the coagulated fiber from the coagulating bath so that the retention time in the coagulating bath is within 60 seconds; and then drawing the fiber in a drawing bath comprising a solvent and a coagulant and having a coagulating property to the dope and a composition such that a skin layer is not formed on the fiber.

Acrylic fiber having excellent durability and dyeability and process for

Described is a cellulose dope which is an aqueous alkali solution containing substantially at least 3% by weight of cellulose having a degree of polymerization of at least 100, wherein in the .sup.13 C-NMR spectrum of the cellulose, the C.sub.4 -position carbon peak is found at a magnetic field higher by at least 7 ppm than the magnetic field of the C.sub.4 -position carbon peak of solid cellulose attributed to the strong intramolecular hydrogen bond. This dope is prepared by maintaining a mixture comprising 100 weight parts of cellulose, which may have any crystal form, and 10 to 1000 weight parts of a hydrogen bond-cleaving solution at 100.degree. C. to 350.degree. C. under a pressure of 10 to 250 atmospheres, promptly exposing the mixture to the ambient atmosphere, mixing the resulting cellulose with an aqueous alkali solution maintained at a temperature not higher than 50.degree. C., and then stirring the mixture at a temperature not higher than 10.degree. C. to dissolve the cellulose in the aqueous alkali solution. The dope may be used for the manufacture of a shaped article or for coating.

Cellulose dope, process for preparation and method for application

Disclosed is carboxymethyl cellulose or its salt derived from cellulose having a crystal form of cellulose II, wherein the total saturation degree &lt;&lt;F&gt;&gt; represented by the following formula:

Cellulose derivative excellent in liquid absorbing property, process for

A mesophase dope useful for producing shaped articles, for example, filaments and films, comprises at least 10% by weight of at least one cellulose derivative and the balance consisting of an aqueous solution of at least 5% by weight of at least one inorganic acid, the dope exhibiting the mesophase property even in the case where no fluid dynamic stress is applied thereto.

Mesophase dope containing cellulose derivative and inorganic acid

A cellulose sulfate salt having a heparinic action is provided, which satisfies requirements of 0.8.ltoreq.&lt;&lt;F&gt;&gt;.ltoreq.2.6, &lt;&lt;f.sub.2 &gt;&gt;.gtoreq.&lt;&lt;f.sub.3 &gt;&gt; and &lt;&lt;f.sub.2 &gt;&gt;.gtoreq.&lt;&lt;f.sub.6 &gt;&gt; wherein &lt;&lt;f.sub.2 &gt;&gt;, &lt;&lt;f.sub.3 &gt;&gt; and &lt;&lt;f.sub.6 &gt;&gt; stand for probability of substitution of atoms H in the OH groups bonded to the C.sub.2, C.sub.3 and C.sub.6 positions of the glucopyranose ring unit by sulfuric acid radicals, respectively, and &lt;&lt;F&gt;&gt; stands for the total substitution degree which is the sum of &lt;&lt;f.sub.2 &gt;&gt;, &lt;&lt;f.sub.3 &gt;&gt; and &lt;&lt;f.sub.6 &gt;&gt;. The cellulose sulfate salt is prepared by reacting a cellulose having a crystal form I with an SO.sub.3 /amine or SO.sub.3 /amide complex in an amount of 2 to 4 mole equivalents per glucose unit of the cellulose at -10.degree. C. to 40.degree. C. to form a gelatinous product; adding water to the gelatinous product in an amount 0.1 to 5 times the amount of the starting cellulose used for the reaction; treating the mixture at a high temperature to relatively reduce the values of &lt;&lt;f.sub.6 &gt;&gt; and &lt;&lt;f.sub.3 &gt;&gt; among the values of &lt;&lt;f.sub.2 &gt;&gt;, &lt;&lt;F.sub.3 &gt;&gt; and &lt;&lt;f.sub.6 &gt;&gt;; neutralizing, precipitating and drying the so obtained crude cellulose sulfate; dissolving the crude cellulose sulfate in water again; treating the solution with an adsorbent; and subjecting the treated cellulose sulfate to precipitation, drying, re-dissolution, dialysis, precipitation and then drying.

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Ikoma, Japan

Kenji Kamide