Hidenari Suyama

Mitsubishi Group (Japan)

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Mitsutaka Uzumaki

Mitsubishi Group (Japan)

Masao Ishii

Meteorological Research Institute

Tomoya Nakajima

Japan Agency for Marine-Earth Science and Technology

Hajime Haioka

Mitsubishi Group (Japan)

Shojun Satake

Mitsubishi Group (Japan)

Masataka Kiyota

Mitsubishi Group (Japan)

Cooperative Institutions

Mitsubishi Group (Japan)

Japan Agency for Marine-Earth Science and Technology

Meteorological Research Institute

Japan Meteorological Agency

Institute for Basic Science

Imperial College London

University of Bristol

University of Glasgow

Universidade do Estado do Rio de Janeiro

Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung

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STUDIES ON THE POLYVINYL ALCOHOL FIBERS

Sen i Gakkaishi (1962)

Hidenari Suyama Tomoya Nakajima

It is well known that conventional formalized polyvinyl alcohol fibers do not possess sufficient elastic recovery to render them applicable to practical uses. One of the prevailing methods which was found to improve the elastic properties of polyvinyl alcohol fibers is to treat the fibers with benzaldehyde. However, the fibers thus treated generally become hydrophobic and need special dyeing processes, because of its poor dyeability.The carrier dyeing process such as the use of benzoic acid, salthilic acid, methylsalicylate, n-buthanol, p-phenylphenol and chlorbenzene were investigated. It was found that methylsalicylate which is emulsified in dyeing bath is most effective as a carrier when the benzalized fibers is dyed by dispersed dyestuffs.

Polyvinyl Alcohol

Benzoic acid

Benzaldehyde

10.2115/fiber.18.100

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STUDIES ON POLYVINYL ALCOHOL FIBERS

Sen i Gakkaishi (1961)

Hidenari Suyama Mitsutaka Uzumaki Masao Ishii

The reaction of polyvinyl alcohol in powder form with aldehydes containing basic groups such as aminoacetaldehyde was studied for the purpose of improving the dye affinity of polyvinyl alcohol fibers. The fibers prepared from partially aminoacetalized polyvinyl alcohol, however, were obsurved to discolor during the heat treatment. Aldehydes containing tertiary amino groups such as dimethyl-amino acetaldehyde dimethyl acetal were found to yield fibers that are less susceptible to discoloration than those containing aminoacetaldehyde dimethyl acetal.Higher reaction temperatures and longer reaction periods are required for the system consisting of polyvinyl alcohol and dimethyl-amino acetaldehyde dimethyl acetal because of the slow rate of reaction. The use of sulphuric acid catalyst in this system is found to yield fibers with poor physical properties as the acid reacts with polyvinyl alcohol to form an ester. Hydrochloric acid, however, gave good results as a catalyst. The degree of preheat treatment of the polyvinyl alcohol powder prior to dimethyl-amino acetaldehyde dimethyl acetalization is found to influence the properties of the fibers. If the polyvinyl alcohol powder ls properly heat treated, then the properties of the fibers will be similar to those obtained from resaponified polyvinyl alcohol. This indicates that dimethyl-amino acetaldehyde dimethyl acetal is selectively incorporated into the polyvinyl alcohol molecule without disturbing crystallization of the fiber. The results of X-ray diffraction are found to be in agreement with the properties of the fibers and the degree of swelling of films prepared from partially dimethyl-amino acetalized polyvinyl alcohol.

Polyvinyl Alcohol

10.2115/fiber.17.1179

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STUDIES ON POLYVINYL ALCOHOL FIBERS

Sen i Gakkaishi (1961)

Hidenari Suyama Mitsutaka Uzumaki

Polyvinyl alcohol was heat-treated in powder form to a degree which will render it soluble in hot water but insoluble in cold water to permit purification with cold water. The heat-treated polyvinyl alcohol was then subjected to a formalization treatment in powder form. It was assumed that the reaction takes place mainly in the amorphous region of the polyvinyl alcohol molecule so that the formalized groups exist as selectively substituted groups and may be considered as a form of block copolymer.This polyvinyl alcohol was employed to study the rate of formalization, the degree of swelling of films and the physical properties of fibers prepared therefrom. Polyvinyl alcohol containing formal groups in the amount not more than 5% appeared to be selectively substituted. Fibers obtained from partially formalized polyvinyl alcohol were found to have improved mecnanical properties, especially improved elastic recovery under low strain.

Polyvinyl Alcohol

10.2115/fiber.17.1079

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STUDIES ON THE POLYVINYL ALCOHOL FIBERS

Sen i Gakkaishi (1962)

Hidenari Suyama Mitsutaka Uzumaki

The strength, particularly their knot-strength, of polyvinyl alcohol fibers is known generally to be reduced by acetalization reaction. Acetalization is carried out in acidic aqueous solution, in which an antiswelling agent such as sodium sulfate is added in order to prevent swelling and shrinkage of the fibers during the acetalization reaction.As a result of investigations on various formalization conditions such as reaction temperature, concentration of each component in reaction bath and pre-treatment with adequate swelling agents, it is found that the decreasing of the concentration of formaldehyde and sulfuric acid in reaction. bath is most effective to prevent lowering of their knot strength.

Polyvinyl Alcohol

Shrinkage

Sodium sulfate

Wet strength

10.2115/fiber.18.96

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STUDIES ON THE POLYVINYL ALCOHOL FIBERS

Sen i Gakkaishi (1962)

Hidenari Suyama Hajime Haioka

As described in our last report, polyvinyl alcohol fibers are treated with such aldehyde as benzaldehyde in order to improve the elastic properties. In the prior article the benzalization reaction has been carried out in the presence of expensive organic solvents.A method of commercial advantage has been found wherein benzalization can be carried out in the presence of water. Since approximately 0.3% of benzaldehyde dissolves in water at 20°C., the fibers are treated in this saturated benzaldehyde solution in the presence of an acid catalyst. The addition of formaldehyde to the reaction bath yields fibers of further improved wet and dry heat resistance compared to those treated with benzaldehyde alone. Furthermore effects upon the dyeability and elastic properties of the fibers can be controlled by controlling the reaction temperature and the respective amounts of formadehyde and benzaldehyde that react with polyvinyl alcohol. Partially dimethylaminoacetalized polyvinyl alcohol was used as a basic raw material in this experiment. If the degree of benzalization is low, a high degree of formalization is obtained and vice versa. Dye absorptivity is good at low degrees of benzalization whereas at higher degrees of benzalization dye absorptivity becomes poor.

Benzaldehyde

Polyvinyl Alcohol

Molar absorptivity

10.2115/fiber.18.207

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Vinylon Filament Produced by Dry Spinning Method

Sen i Gakkaishi (1965)

Hidenari Suyama

10.2115/fiber.21.s162

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STUDIES ON THE POLYVINYL ALCOHL FIBERS

Sen i Gakkaishi (1962)

Mitsutaka Uzumaki Hidenari Suyama

The relation between the average degree of polymerization (D. P.) or its distribution of polyvinyl alcohol (P. V. A.) and physical properties of dry spun fiber was investigated.The stretchability of the obtained fiber was gradually reduced by raising average D. P. but wasremarkably improved by narrowing D. P. distribution. Furthermore, as the results of the continued studies, the poor stretchability was obvious due to the presence of larger molecules in P. V. A. In such case, the fact that the drawn fiber at approx. maximum draw ratio became milky fiber and then was broken.On the study of a few mechanical properties in addition to the above stretchability, it was understood that the tenacity, the elongation, and the hot water resistance were almost independent of the D. P. distribution of P. V. A., but only the hot water resistance was greatly dependent upon the average D. P. of P. V. A.

Polyvinyl Alcohol

Tenacity (mineralogy)

Elongation

Degree of polymerization

10.2115/fiber.18.321

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STUDIES ON THE POLYVINYL ALCOHL FIBERS

Sen i Gakkaishi (1962)

Hidenari Suyama Shojun Satake Masao Ishii Masataka Kiyota

In wet spinning of polyvinyl alcohol fibers, aqueous solutions saturated with salt such as sodium sulfate are usually employd as a coagulation bath. However, sodium sulfate salted out during drying process obstructs the operation such as heat-treatment. As the polyvinyl alcohol fibers, stretched adequately in coagulation bath, become insoluble in water under tension, the effects of washing on the fibers were investigated under the conditions mentioned above. The conclusions were as follows.By washing the stretched fibers under tension, the operations such as drying and heating process became smooth and the strength of the fibers thus removed salt was improved.Conventional wet-spun polyvinyl alcohol fibers microscopically two regions, i.e. the skin and core regions, and show a paler and duller shade as compared with the dry-spun polyvinyl alcohol fibers under same dyeing conditions. Such properties of dyeings seems mainly to be due to the presence of a porous structure of the core in the wet-spun fibers. By stretching the wet-spun fibers at adequate ratio, washing at adequate interval and succeeding drying at high temperature, such fiber structure disappears. The fibers heat-treated and formalized after above treatment show a deeper and brighter shade as compared with conventional wet-spun fibers under same dyeing conditions.

Polyvinyl Alcohol

Synthetic fiber

Salt solution

Sodium sulfate

10.2115/fiber.18.317

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STUDIES ON THE POLYVINYL ALCOHOL FIBERS

Sen i Gakkaishi (1962)

Hidenari Suyama Masao Ishii Mitsutaka Uzumaki

The polyvinyl alcohol made by convenional saponification method of polyvinyl acetate contains generally approximately 0.5mol. % of unsaponified acetyl groups. The properties of thh polyvinyl alcohol fibers depend on the amount of such unsaponified acetyl groups. In wet spinning process of the polyvinyl alcohol fibers, such unsaponified acetyl group can be removed by adding alkali to the spinning solution. The remaining alkali in spinning solution then is neutralized by controlling the pH of the coagulation bath in order to prevent discoloration of the fibers during the heattreatment process.When polyvinyl alcohol is to be spun by a dry spinning process, the raw material must be highly purified to remove all traces of impurities such as alkali and sodium acetate, otherwise the fiber product will tend to discolor during the heat-treatment process. The content of unsaponified acetyl groups could be decreased from 0.6mol. % to 0.05mol. % by means of re-saponifying the polyvinyl alcohol powder (ordinary saponified and then heat-treated) with an aqueous alkaline solution in suspension state. After re-saponification, the sample was washed and then submitted to the dry spinning.As the results, the fibers thus obtained have higher softening temperature and higher hot water resistance than the fibers made of the conventional polyvinyl alcohol. Furtheromore by increasing draw ratio and heat-treatment temperature of such re-saponified polyvinyl alcohol fibers, the fibers having boiling water resistance without acetalization could be obtained.

Polyvinyl Alcohol

Saponification

Polyvinyl acetate

10.2115/fiber.18.217

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STUDIES ON POLYVINYL ALCOHOL FIBERS

Sen i Gakkaishi (1961)

Hidenari Suyama Mitsutaka Uzumaki

Dry spinning of polyvinyl alcohol solutions containing lower members of methylol derivatives and ethylenimine derivatives was studied for the purpose of improving the dye affinity of polyvinyl alcohol fibers. Distinctive differences in the viscosity of the spinning solution and the physical properties of the heat-treated fibers were observed between the spinning solution containing methylol derivatives and that containing ethylenimine derivatives. This is explained by a different reactivities of methylol derivatives and ethylenimine derivatives upon polyvinyl alcohol.

Polyvinyl Alcohol

10.2115/fiber.17.1073

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