Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
2000-07-14
2001-11-06
Hampton-Hightower, P. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phenol, phenol ether, or inorganic phenolate
C528S310000, C528S322000, C528S353000, C428S473500
Reexamination Certificate
active
06313258
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a novel aromatic polycarbodiimide and a film thereof. The aromatic polycarbodiimide of the present invention gives films, moldings, and adhesives each having various excellent characteristics such as high heat resistance, and high dimensional stability.
BACKGROUND OF THE INVENTION
Conventionally, polymerized products of an aromatic diisocyanate such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), etc., have been known as an aromatic polycarbodiimide. Such an aromatic polycarbodiimide has been used as flame and fire resistant films and heat resistant adhesives due to its excellent heat resistance.
A film of a conventionally known aromatic polycarbodiimide has a heat resistance in the point that even when the film is exposed to high temperature of higher than 400° C., the film does not form a volatile gas and decomposed monomers. However, when the film is subjected to a heat treatment at a temperature of higher than 200° C., the film loses the self-retention property and becomes brittle, thereby the film cannot endure the practical use. Further, the film has a low moisture resistance at high temperature and high pressure.
A conventional polymer induced from a known aromatic diisocyanate has the disadvantages that since the polymer has a high melting point, a melt-molding thereof is difficult, and film forming from the polymer solution is difficult because they have low solubility to organic solvents. Further, it may be difficult to generally produce a polymer having a high degree of polymerization for the conventional aromatic diisocyanate. Also, to obtain the mechanical characteristics of the polymer suitable for films and moldings, a divalent aromatic residue in the polymer skeleton must be a p-substituted bond, but such a polymer skeleton has a rigidity and is poor in flexibility.
SUMMARY OF THE INVENTION
As a result of various investigations to overcome the disadvantages of conventional aromatic polycarbodiimides and to obtain an aromatic polymer capable of giving high-efficient films and moldings excellent in heat resistance as well as moldability and flexibility, a novel polymer of the present invention has been successfully obtained.
According to the present invention, there is provided an aromatic polycarbodiimide having a structural unit represented by the following formula (A)
wherein R represents a divalent organic group represented by the following formula (1), (2), or (3) and n represents an integer;
wherein X represents a fluorine atom or a hydrogen atom;
wherein substituting positions of the 2 phenoxy groups bonding to the central benzene ring are 1,3-bonds or 1,4-bonds; and
wherein X represents a fluorine atom or a hydrogen atom.
As a related information where R in the above formula (A) is represented by the above formula (1) , an aromatic diisocyanate represented by the following formula (4) is disclosed in Example 12 of U.S. Pat. No. 4,017,459;
However, there is no description in the above U.S. patent about the production of a polycarbodiimide by polymerizing the aromatic diisocyanate. Furthermore, about the formula (1) in the formula (A) described above, wherein X is a fluorine atom, neither polymers nor monomers are reported.
REFERENCES:
patent: 2941966 (1960-06-01), Campbell
patent: 4017459 (1977-04-01), Onder
patent: 5338794 (1994-08-01), Imashiro et al.
patent: 6008311 (1999-12-01), Sakamoto et al.
patent: 6051677 (2000-04-01), Maeda et al.
patent: 6107448 (2000-08-01), Sakamoto et al.
G. Greber and H.R. Kricheldorf, A New Synthesis of Isocyanates and Isothiocyanates, Angew, Chem. Internat. Edit., vol. 7 (1968) No. 1 p. 941.
V.L.K. Valiii and H. Alper, A Simple, Convenient, and Efficient method for the Synthesis of Isocyanates from Urethanes, J. Org. Chem. 1995, 60, pp. 257-258.
Mochizuki Amane
Sakamoto Michie
Yamamoto Michiharu
Hampton-Hightower P.
Nitto Denko Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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