Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
2002-04-25
2004-02-17
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S523000, C525S905000, C549S517000, C549S539000
Reexamination Certificate
active
06693149
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for preparing a curable polyphenylene ether (PPE) resin. More particularly, the present invention relates to a process for preparing a curable polyphenylene ether resin, which involves introducing an epoxy group-containing functional group to the terminal end of PPE (Mn>3000) by modifying the hydroxy and ester groups on the terminal end.
2. Description of the Prior Art
Communication devices tend to function at higher speeds and frequencies. The substrate material for such devices, such as wireless communication networks, satellite communication equipment, high performance and broadband devices, high speed computers and computer work stations, demands a high glass transition temperature (Tg), low dielectric constant (Dk), and low loss factor (Df). Presently, the copper-clad laminate used for printed circuit boards (PCB) is mainly FR-4, the substrate of which is epoxy resin. However, electrical properties (such as Dk and Df) of FR-4 can no longer meet the increasing needs of high frequency.
Polyphenylene ether (PPE), having high Tg and superior electrical properties, is a potential material for high frequency substrates. Therefore, PPE resin has been introduced into the epoxy-made FR-4 substrate, in order to enhance the limited properties of epoxy resin. However, epoxy resin and PPE resin have great difference in chemical structure. Thus, the chemical comparability between these two resins is inferior. When epoxy and PPE resins are mixed, they cannot undergo crosslinking, and phase separation occurs. It is very difficult to use the PPE-Epoxy resin system in printed circuit boards. Therefore, some researchers have attempted to solve the phase separation when PPE and epoxy are mixed.
For example, in U.S. Pat. No. 4,853,423, after PPE and epoxy resins are mixed, zinc acetylacetonate or zinc stearate is added as a compatabilizer. Thus, coordination bonding is generated between PPE and epoxy and no phase separation occurs. However, the addition of these metal salts makes the substrate have inferior electrical properties.
In U.S. Pat. No. 5,834,565, PPE resin is modified to have a smaller molecular weight. The smaller the molecular weight of PPE, the less chance the phase separation between PPE and epoxy. However, when PPE has a too small molecular weight, particularly less than 3000, the PPE-epoxy resin has inferior electrical properties. The addition of PPE is in vain.
In Japanese Patent No. 09291148, PPE resin is redistributed to obtain a PPE resin with Mn of 1000 to 3000. Then, epoxy functional groups are introduced into the redistributed PPE. Although small-molecular-weight PPE resin has better processability, the glass transition temperature is adversely decreased.
Therefore, there is still a need to develop a new process to solve the inferior comparability and phase separation between PPE and epoxy and to obtain an epoxy group-containing PPE with high glass transition temperature.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-mentioned problems and to provide a process for preparing an epoxy group-containing curable polyphenylene ether resin with high glass transition temperature.
To achieve the above objects, the process for preparing an epoxy group-containing curable polyphenylene ether (PPE) resin of the present invention includes reacting a polyphenylene ether resin represented by formula (I), a strong base, and a compound containing a leaving group and epoxy group to obtain a curable polyphenylene ether resin represented by formula (II).
Formula (I) has a number average molecular weight higher than 3000 and is
wherein
R
1
can be the same or different and is H, alkyl having from 1 to 3 carbon atoms, or
wherein R
11
is alkylene having from 1 to 3 carbon atoms, and R
12
is aryl;
Z
1
can be the same or different and is H, OH, or
and at least one Z
1
is OH or
wherein R
13
is aryl; and
p is from 25 to 165.
The compound containing leaving group and epoxy group has the formula (A):
wherein
X is a leaving group of halogen or sulfonate; and
n is an integer of 1 to 6.
Formula (II) is:
wherein
R
2
can be the same or different and is H, alkyl having from 1 to 3 carbon atoms,
wherein
R
11
is alkylene having from 1 to 3 carbon atoms;
R
12
is aryl;
n is an integer of 1 to 6; and
s is 0 or an integer of 1 to 6;
Z
2
can be the same or different and is H, OH,
and at least one is a group represented by formula (i), wherein R
13
is aryl, n and s are defined above; and
p is 25 to 165.
REFERENCES:
patent: 4732937 (1988-03-01), Sybert
Kang Hung-Chou
Lin Chien-Ting
Yin Meng-Song
Aylward D.
Darby & Darby
Dawson Robert
Industrial Technology Research Institute
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