Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2001-06-28
2003-03-25
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C528S038000, C525S431000, C427S387000, C428S447000
Reexamination Certificate
active
06538093
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a polyimide silicone resin especially less containing volatile cyclic siloxane oligomers, a process for its production, and a polyimide silicone resin composition comprised of it as an effective component and having a good adhesiveness (bond strength).
2. Description of the Prior Art
Polyimide resins are commonly used as materials for printed circuit boards and heat-resistant adhesive tapes because of their high heat resistance and superior electrical insulation properties. Although the polyimide resins are used as resin varnish to form surface protective films and interlayer insulating films of electronic parts and semiconductor materials, they are capable of dissolving only in limited solvents. Accordingly, a method is commonly employed in which a solution prepared by dissolving in an organic solvent a polyimide precursor polyamic acid capable of relatively readily dissolving in various organic solvents is coated on a substrate, followed by removal of the solvent and then high-temperature treatment to effect dehydration cyclization and the product obtained is used as polyimide resin. Also, in order to, e.g., improve the solubility of polyimide resin in solvents, improve its adhesive force to substrates and impart flexibility, it is popular to introduce a siloxane chain into the polyimide skeleton. Siloxane materials widely used to introduce a siloxane chain into the polyimide skeleton are diaminosiloxanes, i.e., straight-chain silicones having amino groups at both terminals.
However, diaminosiloxanes which are commonly available contain cyclic siloxanes as impurities. Some cyclic siloxanes are volatile, and such volatile siloxanes are known to cause trouble in electrical contacts of relays, switches, motors and so forth used in electronic and electrical equipment. Also, as is seen from the fact that siloxanes are used as release agents (parting agents), they have had a problem that the presence of cyclic siloxanes in polyimide silicones may lower the adhesiveness or bond strength to substrates.
Meanwhile, electronic and electrical equipment or semiconductor chips are increasingly made compact or made high-performance. Accordingly, it is long-awaited to provide a polyimide silicone resin or polyimide silicone resin composition having a high reliability and a high adhesiveness.
SUMMARY OF THE INVENTION
Under such circumstances, an object of the present invention is to provide a polyimide silicone resin made to less contain the cyclic siloxane oligomers causative of the trouble in electrical contacts, a process for its production, and a polyimide silicone resin composition comprised of such a resin as an effective component and showing a good adhesiveness (bond strength) to substrates and a high reliability.
As a result of extensive studies made in order to solve the problems discussed above, the present inventors have discovered that a polyimide silicone resin less containing cyclic siloxane oligomers and having a relatively low glass transition point and a composition containing this resin as an effective component can solve the problems. They have also discovered that the polyimide silicone resin less containing cyclic siloxane oligomers can be obtained by using as a diamine component a diaminosiloxane less containing cyclic siloxane oligomers. Thus, they have accomplished the present invention.
More specifically, the present invention in the first aspect provides a polyimide silicone resin which contains not more than 300 ppm of a cyclic siloxane oligomer having 10 or less silicon atoms, has a glass transition point of 250° C. or below and is soluble in an organic solvent.
The present invention in the second aspect provides a process for producing a polyimide silicone resin from a tetracarboxylic dianhydride and a diamine, wherein the diamine contains a diaminosiloxane represented by the following general formula (10), and the diaminosiloxane contains not more than 300 ppm of a cyclic siloxane oligomer having 10 or less silicon atoms.
wherein n represents an integer of from 0 to 120, and R
1
and R
2
each represent an alkyl group having 1 to 8 carbon atoms or a phenyl group.
The present invention also in the third aspect provides a polyimide silicone resin composition comprising from 50% by mass to 99% by mass of the above polyimide silicone resin and from 1% by mass to 50% by mass of an epoxy compound.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described below in detail.
In the polyimide silicone resin of the present invention, a cyclic siloxane oligomer having 10 or less silicon atoms is kept in a small content.
In the present invention, the cyclic siloxane oligomer having 10 or less silicon atoms may include, for example, compounds represented by the following general formula:
(R
3
R
4
SiO)
m
wherein R
3
and R
4
may be the same or different and each represent an alkyl group having 1 to 8 carbon atoms or a phenyl group, the alkyl group including e.g., a methyl group, an ethyl group or a propyl group; and m is an integer of 3 to 10; and may specifically include hexamethylcyclotrisiloxane and octamethylcyclotrisiloxane. Any of these cyclic siloxane oligomer in the polyimide silicone resin must be in a content not more than 300 ppm in order to materialize a high reliability and a high adhesive performance. It may more preferably be in a content of 100 ppm or less.
The polyimide silicone resin of the present invention may also preferably have not so high glass transition point in order to materialize a good adhesiveness or bond strength. It may have a glass transition point of 250° C. or below, and more preferably from 50° C. to 200° C.
When the polyimide silicone resin of the present invention is used as a component of adhesives, it is dissolved in an organic solvent to prepare them, and hence must be soluble in the organic solvent.
The organic solvent used here may include polar solvents such as N-methyl-2-pyrrolidone, cyclohexanone, N,N-dimethylformamide and N,N-dimethylacetamide, ketone type solvents such as 2-butanone and 4-methyl-2-pentanone, and ether type solvents such as tetrahydrofuran and propylene glycol dimethyl ether.
As methods for making the content of the cyclic siloxane oligomer small in the polyimide silicone resin, known methods may be used, which may include, e.g., a method in which the polyimide silicone resin is once dissolved in a solvent and thereafter re-precipitated to take out the polyimide silicone resin to bring the cyclic siloxane oligomer into a small content, and a method in which a siloxane originally having the cyclic siloxane oligomer in a small content is used as a material. In particular, the method in which a siloxane originally having the cyclic siloxane oligomer in a small content is used as a material is desirable from the viewpoint of saving of natural resources and power saving.
As this siloxane material, it is preferable to use the diaminosiloxane represented by the general formula (10). In this diaminosiloxane, the cyclic siloxane oligomer may preferably be in a content not more than 300 ppm, and more preferably not more than 100 ppm. As methods for making the content of the cyclic siloxane oligomer small in the diaminosiloxane, known methods may be used, which may include, e.g., methods such as striping at high temperature and extraction making use of a solvent. In the general formula (10), n represents an integer of from 0 to 120, and R
1
and R
2
each represent an alkyl group having 1 to 8 carbon atoms or a phenyl group.
As the above polyimide silicone resin, it is preferable to use a polyimide silicone resin having repeating units represented by the following general formulas (a) and (b).
In the formulas;
X is at least one organic group selected from tetravalent organic groups represented by the formulas (1), (2) and (3):
Y is an organic group selected from i) a divalent organic group represented by the general formula (4):
where B is at least one organic group selected from organic groups represented by the for
Kato Hideto
Sugo Michihiro
Moore Margaret G.
Shin-Etsu Chemical Co. , Ltd.
LandOfFree
Polyimide silicone resin, process for its production, and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Polyimide silicone resin, process for its production, and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polyimide silicone resin, process for its production, and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3036196