Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1985-10-24
1987-03-24
Marquis, Melvyn I.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
357 72, 524104, 524167, 524173, 524211, 524233, 524323, 528 26, 528 38, 556419, 556423, C08K 534
Patent
active
046525980
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
This invention relates to improved polyamic acids prepared by the reaction of dianhydrides (or trianhydrides) with diamines containing about 0.75 to about 5 mole percent of a polysiloxane incorporated in the backbone of the polyamic acid. Such polyamic acids, preferably dissolved in a suitable solvent, are readily converted into shaped polyimide articles which are relatively free of voids, pinholes, crack and bubbles. The polysiloxane incorporated in the backbone of the polyamic acid enables the water of imidization and any solvent present to be readily removed without producing significant imperfections in the shaped polyimide article prepared by imidization of the polyamic acid. The polysiloxane has a monomeric unit formula of ##STR1## or of formula ##STR2## where the substituents are all as defined below.
DESCRIPTION OF THE PRIOR ART
U.S. Pat. No. 4,395,527 teaches that the properties of various polymers can be improved by the incorporation of a siloxane unit; the present invention relates to the discovery that low levels of siloxane incorporated into a polymer improve the drying of films or coatings without significantly affecting the other properties of the polymer.
BACKGROUND OF THE INVENTION
Polyamic acids, prepared by the reaction of dianhydrides (or trianhydrides) with diamines are typically prepared in high-boiling solvents such as diglyme or N-methylpyrrolidone. When used for coating purposes or for making film they are heated step-wise to 300.degree. C. to remove water of imidization and solvent. Certain poly(half-amides) particularly those containing polar groups, are very difficult to free of solvent because of their high polarity. Further, after heating at temperatures as high as 300.degree. C., films prepared from these systems tend to have significant numbers of bubbles or voids that are inimical to film quality.
It has been found unexpectedly, that when about 0.75 to about 5 mole percent of a polysiloxane are incorporated in polyamic acid backbone, the polyimide film formed can be more easily freed of solvent and water of imidization than a control film containing no polysiloxane.
DESCRIPTION OF THE INVENTION
It has been found that the drying properties of polyamic acids can be improved by the presence of about 0.75 to about 5 mole percent of a polysiloxane having a monomeric unit formula of ##STR3## or of formula ##STR4## where Q is a substituted or unsubstituted aromatic group; ##STR5## R and D is each unsubstituted or substituted hydrocarbylene; R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5 and R.sup.6 each independently unsubstituted or substituted hydrocarbyl; from 1 to 100. are suited for a variety of high-performance applications.
The monomeric unit of formula ##STR6## or of formula ##STR7## is derived from a bis(functional)polysiloxane of formula ##STR8## or of formula ##STR9## where F.sub.1 is a primary amino group (i.e. --NH.sub.2) or a dicarboxylic acid anhydride group (i.e. ##STR10## and Q, Z, R, D, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, x, y, z and w are as described above.
F.sub.1 can be directly bonded to Q or bonded via an intermediate alkyl or alkoxy group of from 1 to 8 carbon atoms, an aryl group, or via an intermediate Q--Z-- group.
Q is an aromatic nucleus and can be carbocyclic or heterocyclic; it can contain one or more rings and can be unsubstituted or substituted by one or more groups that do not interfere with the use to which the unit will be put. Thus, Q can be carbocyclic aromatic of 6 to 18 ring carbon atoms such as phenylene, naphthylene, anthracenylene and phenanthrylene. Q can be unsubstituted or substituted by from 1 to 4 of: alkyl or 1 to 12 carbon atoms, alkenyl of 2 to 12 carbon atoms, alkynyl of 2 to 12 carbon atoms, cycloalkyl of 4 to 8 carbon atoms, alkoxy of 1 to 12 carbon atoms, alkylthio of 1 to 12 carbon atoms, phenyl, alkylphenylene having 1 to 12 carbon atoms in the alkyl group, phenoxy, phenylthio, alkylcarbonyloxy of 2 to 12 carbon atoms, phenylalkylene of 1 to 12 carbon atoms in the alkylene gro
REFERENCES:
patent: 3926911 (1975-12-01), Greber et al.
patent: 4395527 (1983-07-01), Berger
patent: 4520075 (1985-05-01), Igarashi et al.
Bright R. E.
M&T Chemicals Inc.
Marquis Melvyn I.
Matalon J.
Parker S. H.
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