Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From silicon reactant having at least one...
Reexamination Certificate
2002-08-19
2004-08-10
Robertson, Jeffrey B. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From silicon reactant having at least one...
C528S012000, C528S020000, C528S021000, C528S034000, C556S450000, C556S455000, C556S459000, C556S460000, C556S463000, C556S464000, C556S466000, C556S467000, C525S474000
Reexamination Certificate
active
06774202
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to polyorganosilsesquioxane and a process for preparing the same, and more particularly, to polyorganosilsesquioxane having organosilanetriol as starting materials, and a process for preparing the same.
2. Description of the Related Art
With the development of high-level advanced technology, research into high-performance, multi-functional high-technology materials is being conducted in various fields. In particular, in research into novel polymeric materials, much attention has been paid to novel high-functional organic polymers, e.g., organic polymers having improved heat resistance and glass transition temperature (T
g
), and technology of forming organic or inorganic hybrid materials, such as an organic and inorganic hybrid complex.
There are known many existing organic or inorganic hybrid materials. In particular, due to importance of thermal stability between organic polymer and inorganic polymer, keen attention is focused on polyorganosilsesquioxane, which is a high-heat-resistance polymer.
Polyorganosilsesquioxane was first introduced in an article of J. Am. Chem. Soc., 82, 6194 (1960) by Brown et al., and commercialized in trade names of “Glass-resin” and “SST-resin” by Owens Illinois and Gelest. However, polyorganosilsesquioxane is not being put into practical use as industrial material because of difficulties of controlling the polymer structure and adjusting the molecular weight thereof.
A highly regular ladder form of polyorganosilsesquioxane accounts for its improved performance properties. Thus, along with development of novel starting materials that can easily form a ladder-form structure, research into condensation methods thereof has been made in various fields of industry in various ways.
Among known methods of preparing polyorganosilsesquioxane, a representative method is to dehydrate and condense a precursor hydrolyzed product (oligomer), synthesized by hydrolyzing trichlorosilane or trialkoxysilane in the presence of alkali/acidic catalyst, thereby easily obtaining a low-molecular weight polymer (having a number-average molecular weight (M
n
) of 20,000 to 30,000 and a degree of dispersion (M
w
/M
n
) of 3 to 5.
A conventional method of preparing polyorganosilsesquioxane using trichlorosilane will first be described. Oligomer produced by co-hydrolytic condensation when hydrolyzing trichlorosilane, the oligomer having of M
n
of 1,000 to 2,000 and a polydispersity index value (PDI) of 2 to 5, has a complicated, diverse structure, compared to silanetriol which is a single structure. In the case of forming high-molecular weight oligomer, a three-dimensional network structure is easily formed by constructural deformity due to the presence of inter-hydroxy group, and the inherent structure of oligomer, having the following disadvantages: 1) The structure of produced polymer is uncontrollable; 2) It is difficult to adjust the molecular weight of produced polymer and to obtain high-molecular weight polymer; 3) The produced polymer loses high regularity, lowering solubility against solvent; and 4) Remaining low-molecular weight components may adversely affect the heat resistance and mechanical property of polymer.
A conventional process for preparing polyorganosilsesquioxane using trialkoxysilane is also advantageous from the viewpoint of handling convenience, such as controllability of a hydrolysis rate, compared to trichlorosilane. However, various studies reported that this process had the following disadvantages caused by the oligomer molecular deformity due to the presence of inter-hydroxy group, and by the presence of alkoxy group: 1) A polymer of a branch structure, rather than a ladder structure, is formed; 2) selection of catalyst used, amount of the selected catalyst, selection of reactant solvent, careful adjustment of pH of selected reactant solvent, and so on, are not easy to achieve; and 3) a three-dimensional network structure causes micro-gelation. These disadvantages may adversely affect preparation of highly regular silicon ladder-form polymer.
As described above, a great attention has been paid to polyorganosilsesquioxane and constant research into the same has been made. According to known various synthesizing methods, e.g., a sol-gel method, a ring-opening polymerization method or an equilibrium polymerization method, and research into the structure of polyorganosilsesquioxane, condensation thereof is very complicated and versatile, so that the structure of polymer cannot be sufficiently controlled. Thus, even a product commercially available in the trade name of glass resin, also called T-type resin, cannot meet several requirements to be used as a novel industrial material, which becomes impediment to practical use.
Requirements of novel industrial materials using organic or inorganic hybrid materials are: a low dielectric constant of 2 to 3; excellent thermal stability such as a pyrolysis starting temperature of 400° C. or higher; low hygroscopicity; a low thermal expansion coefficient; excellent gap filling capability; excellent bondability.
To overcome the above-described problems, the present inventors proposed polyphenylsilsesquioxane having high regularity and crystallinity, which cannot be controlled by conventional methods, using high-purity organosilanetriol as a starting material, rather than oligomer having various molecular weights and structures.
However, there is still a need for polyorganosilsesquioxane having high regularity/crystallinity.
SUMMARY OF THE INVENTION
It is an objective of the present invention to provide a novel high-technology inorganic material having excellent properties through development of new precursors, and preparation method thereof, the precursors being: 1) easy in handling; 2) capable of adjusting the rate of polymerization; 3) capable of uniformly distributing hydroxy groups at both ends of polymer; 4) capable of introducing R—SiO
3/2
to the main chain of polymer with high regularity; 5) easily capable of adjusting the crosslinking structure of polymer, specifically, crosslinkablity or crosslinking density; 6) capable of facilitating chemical modification by spreading the structure of polymer; 7) easily capable of forming nano-sized pores in the backbone of polymer; and 8) capable of imparting high functionality and versatile properties to polymer.
To accomplish the above objective of the present invention, there is provided polyorganosilsesquioxane and a process for preparing the same.
Polyorganosilsesquioxane according to the present invention is a compound represented by formula 1, 2 or 3:
wherein R
1
is a hydrogen atom, an unsubstituted or substituted aliphatic hydrocarbon group having 1 to 30 carbon atoms, an unsubstituted or substituted aromatic hydrocarbon group having 1 to 30 carbon atoms, an unsubstituted or substituted alicyclic hydrocarbon group having 1 to 30 carbon atoms, an unsubstituted or substituted silyl group having 1 to 30 carbon atoms, an unsubstituted or substituted allyl group having 1 to 30 carbon atoms, an unsubstituted or substituted acyl group having 1 to 30 carbon atoms, a vinyl group, an amine group, an acetate group or an alkali metal, and n is an integer of 2 to 300,000.
wherein R
1
is as defined above, R
3
is as defined as in R
1
, l is a multiple integer of 2, ranging from 2 to 300,000, and m and n are integers from 2 to 300,000.
wherein R
1
, R
3
, l, m and n are as defined above.
Cyclictetraorganosilsesquioxane represented by formula 4 is provided as a precursor for preparing the compound represented by Formula 1, 2 or 3:
wherein R
1
is as defined above.
The process for preparing the cyclictetraorganosilsesquioxane represented by formula 4 provided as a precursor for preparing the polyorganosilsesquioxane according to the present invention can be expressed in the reaction scheme 1:
wherein R
1
is as defined above.
As expressed in the reaction scheme 1, the cyclictetraorganosilsesquioxane represented by formula 4 provided as a precursor for preparing the polyorganosilses
Intersilicone Ltd.
Robertson Jeffrey B.
Rothwell Figg Ernst & Manbeck P.C.
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