Compositions: coating or plastic – Coating or plastic compositions – Carbohydrate or derivative containing
Patent
1982-12-01
1984-07-17
Griffin, Ronald W.
Compositions: coating or plastic
Coating or plastic compositions
Carbohydrate or derivative containing
106176, 106191, 106195, 106187, 360134, 149 96, 149100, 524 31, 524590, 536 35, C08L 118, C08L 7504, G11B 570
Patent
active
044604114
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to nitrocellulose chips containing substantially no water and a process for producing the same. More particularly, the present invention relates to nitrocellulose chips suitable for preparing a magnetic tape binder and a process for producing the same.
BACKGROUND ART
At present, the magnetic tape is produced mainly by coating a binder containing magnetic powder onto a plastic film such as polyester and cellulose acetate.
The film-forming material of the magnetic tape binder is selected from polyurethane resin which is crosslinked with an isocyanate compound, a thermoplastic resin such as polyvinyl acetate, polyester, and vinyl chloride-vinyl acetate copolymer, and a mixture thereof. There is disclosed in some known literature that polyurethane resin which is crosslinked with an isocyanate compound is improved in the adhesion and surface hardness when incorporated with nitrocellulose. (Japanese Patent Publication Nos. 6428/1967, 22065/1972, 24522/1973, and 48004/1977)
If water or alcohol as a wetting agent for nitrocellulose is brought into the binder composition, it reacts with isocyanate, impairing the effect of nitrocellulose. Therefore, it is desirable to incorporate the binder with nitrocellulose which contains substantially no water nor alcohol reactive with isocyanate.
A nitrocellulose composition containing no water or alcohol is prepared by replacing water or alcohol with an organic solvent which contains no active hydrogen and does not dissolve nitrocellulose as disclosed in Japanese Patent Publication Nos. 20230/1969 and 9397/1970, or by removing the wetting agent while roll-milling a binder resin for magnetic tapes and nitrocellulose wetted with water or alcohol and then dissolving the resulting resin-nitrocellulose mixture in a solvent inert to isocyanate as disclosed in Japanese Patent Laid-Open No. 142756/1977. These methods still involve problems.
Nitrocellulose wetted with an organic solvent which is inert to isocyanate and does not dissolve nitrocellulose has a disadvantage that the organic solvent is unevenly distributed and is easily charged with electricity because of its low dielectric constant. Thus, it needs care in storage and transportation. Roll-milling with resin requires heating to remove the wetting agent, and this heating discolors nitrocellulose due to thermal decomposition and impairs the working environment with solvent vapors. In addition, some resins stick to the roll, making rolling work difficult with danger and decreasing the operating efficiency.
DISCLOSURE OF INVENTION
In order to overcome the above disadvantages, the present inventors have carried out a series of researches which led to the findings that water disappears selectively from nitrocellulose and an organic solvent remains when nitrocellulose wetted with water is mixed with an organic solvent inert to isocyanate at a certain ratio and the resulting doughlike composition is extruded or rolled into a sheet or string having a large surface area, which is then dried at a comparatively low temperature. The present invention is based on these findings.
The present invention covers a nitrocellulose composition in the form of chips containing 50 to 80 wt% of nitrocellulose and less than 1 wt% of water and a process for producing the same, said process comprising the steps of dissolving nitrocellulose and polyurethane resin in water-wetted nitrocellulose, adding an organic solvent inert to isocyanate in an amount of 30 to 300 parts by weight, preferably 50 to 300 parts by weight, based on 100 parts by weight of dry nitrocellulose, mixing, rolling or extrusion molding, drying at 30.degree. to 55.degree. C., preferably at 30.degree. to 45.degree. C., and cutting.
The nitrocellulose used in this invention is wetted with less than 50 wt% of water and contains nitrogen preferably in an amount of 10.7 to 12.2 wt%.
The organic solvent used in this invention dissolves nitrocellulose and polyurethane resin and does not contain such groups as OH, COOH, and NH.sub.2 which a
REFERENCES:
patent: 3163567 (1964-12-01), Silk
patent: 3280746 (1966-10-01), Brown
patent: 3346675 (1967-10-01), Sapiego
patent: 3671515 (1972-06-01), Cox et al.
patent: 3702271 (1972-11-01), Henderson et al.
patent: 3741781 (1973-06-01), Plazanet et al.
patent: 3824108 (1974-07-01), Stoetzer et al.
patent: 3861932 (1975-01-01), Kabacoff et al.
patent: 3925125 (1975-12-01), Cox et al.
patent: 3948675 (1976-04-01), Rat et al.
patent: 3962382 (1976-06-01), Johnson et al.
Chemical Abstracts, vol. 88, No. 24, Jun. 12, 1978, p. 763, Abstract No. 88:181587g.
Higuchi Akihiko
Ohtake Etsuo
Daicel Chemical Industries Ltd.
Griffin Ronald W.
LandOfFree
Nitrocellulose composition and process for producing the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Nitrocellulose composition and process for producing the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nitrocellulose composition and process for producing the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1489362