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Historical development of manufacturing technology of viscose rayon fibers at Stages IV, V and VI, defined in the previous paper (This journal, 20, 1 (2005)), was studied. In particular, since Stage V was the time of social turbulent the study was made in close connection with social background. As supplement to the previous paper, details (causes and cut-off rate) of the operational curtailments with a golden age sandwiched between them in Stage III was surveyed. Conversion of autonomic control system (Stage III) to governmental compulsory control system (Stage IV) was studied on the basis of acts, royal ordinances, ministerial ordinances and notices. The first～fifth order national plans of reduction of production and the corresponding Asahi's achievements were examined. Numerous difficulties, such as shortage of resources, energy, and man-power, encountered by Japanese rayon producers in Stage IV (1938～1945) were investigated. Technological advance (if any) in Stage IV was studied: R & D activity of Asahi men (in comparison with that in Stage III), some key technology developments continued from Stage III, and Toramomen. The route of invention and commercialization of Tramomen at Asahi in Stage IV and at Tachikawa Research Institute in Stage V and evolution of Toramomen were surveyed. New concept of high-wet-modulus rayon (Toramomen, Polynosic rayon) and the worldwide evaluation of Toramomen (polynosic) were disclosed in detail. History of some restoration plans, approved by GHQ, in Stage V (1946～1951) was surveyed together with Asahi's restoration work. During Stage VI (1952～1956) the USA's technology, directly licensed to Japanese machinery manufactures, was introduced to Japanese viscose rayon producers. Characteristics of the technology at Stage VI were discussed.

First, whole history of Japanese viscose rayon industry was divided into eight stages: Stage I (embryo), Stage II (introduction), Stage III (un-aided development), Stage IV (mid-war ordeal), Stage V (post-war reconstruction), Stage VI (post-war expansion), Stage VII (long-term recession) and Stage VII (reformation). In the previous studies the technological advance at Stage II was studied comprehensively. In this article, study on the development of manufacturing technology in Japanese viscose rayon industry at Stage III (1930～1938) was attempted in systematic manner.

An atempt was made to evaluate the unperturbed chain dimensions A of polyacrylonitrile with a wide range of stereoregularity, and of copolymers of acrylonitrile (AN) and methacrylonitrile (MA) or vinylidene chloride (VDC). For this purpose, the fraction, separated from four PAN samples with meso-meso triad content mm=26, 51, 71 and 75% and together with those of copolymers from AN/MA (AN weight % ; 92) and AN/VDC (AN weight % :59) were utilized. The light scattering and viscosity data obtained for the above fractions were analyzed by the methods 2A～2G, proposed previously.

An attempt was made to investigate apre-history of emergence of chemical fiber industry. Socially widely prevailed tendency in late 19th century to produce high-value products by modifying chemically the naturally-occurred materials, which had been exclusively employed for low-value commodity, formed a strong incentive to invent new artificial materials such as cellulose nitrate. Existing industries were activated remarkably by replacing the natural materials with cellulose nitrate, which was then applied to bear new industries. Chemical fiber industry was a typical example. Numerous trials to produce artificial fiber from other materials than natural silk were historically surveyed mainly on the patent specifications. All the inventions, except Swan's, prior to Chardonnet's, were of 'Imagination Age'. Artificial thread was first produced temporarily on a small scale for electric incandescent lamp by carbonizing cellulose nitrate (to obtain carbon conductor). Electric lamp industry was a precursor of artificial industry. Five essential steps were noticed to be fulfilled concurrently to produce artificial silk for cloth or textiles. It was shown that all essential steps each had been invented, even though being far from perfection, separately by others than Chardonnet prior to Chardonnet's invention, which was commercialized on large scale for clothing. Chardonnet's process was consisted of cellulose nitrate, collodion, dry (or wet) spinning and after-treatment (denitration). In this sense, there was no significant originality in the principle of his process. However, Chardonnet's technology, judged from his patent specifications, was outstandingly precise and accurate enough to enable any one of average engineers or chemists to reproduce Chardonnet's invention by following the specification alone. Then, his patent specifications are equivalent or sometimes superior to contemporary scientific and technical papers. Chardonnet was the first, who used the term 'artificial silk' for the fibers spun from collodion. Chardonnet was also the first person, who applied his inventions internationally, and was the most productive: He had obtained 44 patents, which can be classified into 15 categories, ranging from 1884 to 1923 over almost 40 years (until one year before his death). These inventions had been commercialized worldwide by himself with financial help of investors. His predecessors each applied only single patent, which was not commercialized, to one country. Chardonnet studied at first in laboratory, then established a bench plant, which he operated for several years to accumulate know-how before commercialization. His development procedure is technologically very reasonable and now widely adopted in industry. Chardonnet's process evolved continuously even after commercialization.

In 1921 Asahi Kenshoku (AKS) had introduced a viscose rayon techonology from a German leading company, Vereinigte Glanzstoff A. G. (VGF), forming a first world-scale Japan-foreign joint venture with BGF (20% share holder of the capital) and establighing a plant under guidance of VGF. Afterwards, AKS catched up Europe technology. In this article an attempt was made to clarify the prcess of catch-up.

An attempt was made to uncover and investigate, from meticulous analysis on the data base of scientific papers, reviews and patents constructed in the previous paper (This journal, vol. 17, (2002)), R & D achievements of 25 ex-Asahi chemist individuals, before and during work at and after resignation from Asahi. Total number of the publications amounted to 26, 60 and 154, corresponding to the above three periods. Average duration of the employment by other organizations before joining to Asahi was 3.7 years. Judging from previous job career and R & D achievements, 3 experienced graduate chemists, 3 mid-career technical college graduates and 13 new recruitments joined to Asahi in 1919～1927. Five individuals, all of them belonging to the categories of the established and mid-career engineers, published totally 12 papers, 7 reviews (Code no. 1) and 5 patents (Code no. 6) before joining to Asahi. Ex-Asahi engineers, who resigned from Asahi before full retirement (defined as Group I), stayed on average 6 years at Asahi. All Asahi engineers, who were once employed by Asahi, published 16 papers and 44 patents at Asahi. Close correlation was confirmed among them between the productivity of scientific research and that of technological development. Research activity of some major chemists was investigated in connection with their job positions. Role of Asahi chemists was demonstrated in the three cases to vary significantly, depending on the time of resignation from Asahi.

An attempt was made to construct the most reliable database on stereoregular polyacrylonitrile (PAN) solutions for further analysis. For this purpose, literature data, reported for these 25 years by Kamicle and his coworkers at Asahi, on light scattering and limiting viscosity number [η] of PAN with various tacticity (meso-meso triad content of 26-75%) dissolved in solvents including aq. nitric acid with concentration 51-80% were utilized. The molecular weight dependences of [η]([η] = K_mM_w^a; M_w: weight-average molecular weight) and of the radius of gyration _z^ = (_z^ = K_γM_ω^γ) wene evaluated for each polymer solutions. Flory's theta solvent compositions were determined experimentally as the solution, in which the second virial coefficient A_2 vanishes a = γ = 0.5 holds in Flory solvents. The unperturbed chain dimension A and Flory viscosity parameter φ_0 were directly determined at Flory condition.

An attempt was made to survey the research and development activity of Asahi engineers before, during work at and after employment at Asahi Jinzo Kenshi (AJK) and its successor Asahi Kenshoku (ASK), which introduced a total system of German technology of viscose rayon in the form of the first joint venture with Vereinigte Glanzatoff Fabriken A. G in Japan, in 1920-1940s. For this purpose the thorough publication lists including scientific papers, reviews, books and patents were constructed exhaustively for twenty two + three Asahi engineers, using Complete Abstracts Japanese Chemical Literature and Japanese Patent Publications.