Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phenol – phenol ether – or inorganic phenolate
Reexamination Certificate
1999-09-23
2001-06-19
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
C528S044000, C528S048000, C528S052000, C528S173000, C528S174000, C528S220000, C528S224000, C528S310000, C528S322000, C528S350000, C528S351000, C528S353000, C428S473500
Reexamination Certificate
active
06248857
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an aromatic polycarbodiimide and a polycarbodiimide sheet. More particularly, the present invention relates to an aromatic polycarbodiimide having high heat resistance, low hygroscopicity and a low dielectric constant and to a sheet made from such an aromatic polycarbodiimide.
2. Description of the Related Art
There have been known aromatic polycarbodiimides produced by polymerizing diphenylmethane diisocyanate (MDI) or tolylene diisocyanate (TDI) as a monomer. These aromatic polycarbodiimides are used as flame resistant films or heat resistant adhesives because of their excellent heat resistance.
From the point of view that these aromatic polycarbodiimide films do not generate a volatile gas or decomposed monomer even when they are exposed to a temperature higher than 400° C., it can be said that these aromatic polycarbodiimide films have acceptable heat resistance. However, they have low moisture resistance, and loses self supporting properties and become fragile when they are heat-treated at 200° C. or more, so that they are not fit for practical use. In addition, they have poor solubility in an organic solvent and low workability.
SUMMARY OF THE INVENTION
The inventors of the present invention have conducted intensive studies on various raw material monomers and aromatic polycarbodiimides to obviate the above defects of the conventional polycarbodiimides. As a result, they have found that the above problems can be solved by a polycarbodiimide having the following new skeleton and accomplished the present invention based on this finding.
1) In a first aspect, the present invention provides an aromatic polycarbodiimide comprising a structure represented by the following formula (1):
wherein Q is one selected from the group consisting of —CH
2
—,
m is 0 or 1, A is a divalent organic group having 4 or less carbon atoms, Ph is a phenyl group, X's are a hydrogen atom when Q is
and the same or different halogen atoms when Q is —CH
2
—, and n is an integer of 2 to 300.
2) The aromatic polycarbodiimide according to 1) above, which the structure represented by the above formula (1) may be contained in an amount of more than 10 mol %.
3) The aromatic polycarbodiimide according to 1) above, which n may be an integer of 4 to 100 in the formula (1).
4) The aromatic polycarbodiimide according to 1) above, which n may be an integer of 4 to 40 in the formula (1).
5) The aromatic polycarbodiimide according to 1) above, which the aromatic polycarbodiimide may comprise a structure represented by the following formula (2):
wherein n is an integer of 2 to 300, m is 0 or 1, A is a divalent organic group having 4 or less carbon atoms, and Ph is a phenyl group.
6) The aromatic polycarbodiimide according to 1) above, which the aromatic polycarbodiimide may comprise a structure represented by the following formula (3):
wherein n is an integer of 2 to 300.
7) The aromatic polycarbodiimide according to 1) above, which the aromatic polycarbodiimide may comprise a structure represented by the following formula (4):
wherein n is an integer of 2 to 300, and X's are the same or different halogen atoms.
8) In a second aspect, the present invention provides a polycarbodiimide solution prepared by dissolving the aromatic polycarbodiimide in an organic solvent, wherein the aromatic polycarbodiimide is one selected from the group consisting of 1) to 7) above.
9) In a third aspect, the present invention provides a polycarbodiimide sheet, which comprises as a main ingredient the aromatic polycarbodiimide, wherein the aromatic polycarbodiimide is one selected from the group consisting of 1) to 7) above.
Regarding the aromatic polycarbodiimide having a structure represented by the formula (2), the aromatic polycarbodiimide represented by the following formula
(wherein n is an integer, the position of substitution of the two phenoxy group attached to the central benzene ring is 1,3- or 1,4-) is known (Japanese Patent Application Laid-open No. Hei 9-235341). However, there has been no report on the aromatic polycarbodiimide having a substituent on the central benzene ring in the repeating unit of the main chain as in the present invention. By introduction of a substituent on the central benzene ring in the repeating unit of the main chain, the polycarbodiimide of the present invention has improved solubility and heat resistance as compared with the corresponding polymer without such substituents.
Also, regarding the aromatic polycarbodiimide having a structure represented by the formula (4), the polycarbodiimide represented by the following formula
(wherein R
2
and R
3
independently represent a hydrogen atom, a low alkyl group or an alkoxy group, X represents an oxygen atom or a methylene group) is known (Japanese Patent Application Laid-open No. Hei 3-62814). However, there has been no report on the aromatic polycarbodiimide having a halogen atom on the benzene rings in the main chain as in the aromatic polycarbodiimide having a structure represented by the formula (4) of the present invention.
Other objects and advantages of the present invention will become apparent from the detailed description to follow taken in conjunction with the appended claims.
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G. Greber et al., A New Synthesis of Isocyanates and Isothiocyanates, Angew. Chem Internat Edit vol. 7 (1968) No. 12, p. 941. The month in the date of publication is not available.
Tod W. Campbell et al., “Carbodiimides. IV. High Polymers Containing the Carbodiimide Repeat Unit” Journal of American Chemical Society, vol. 28, pp. 2069-2075 (1963). The month in the date of publication is not available.
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Matsumura Akiko
Misumi Sadahito
Mochizuki Amane
Sakamoto Michie
Satsuma Michio
Hampton-Hightower P.
Nitto Denko Corporation
Sughrue Mion Zinn Macpeak & Seas, PLLC
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