Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2002-03-22
2003-06-10
Dawson, Robert (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C525S481000, C525S525000, C525S533000, C528S099000, C528S112000, C549S512000, C549S522000
Reexamination Certificate
active
06576690
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a phosphorous-containing flame retarding epoxy resin and their composition comprising the nitrogen-containing flame retarding epoxy resin. More specifically, the present invention relates to a flame retarding epoxy resin having a pendent phosphorous-containing functional group and their composition comprising the nitrogen-containing flame retarding epoxy resin.
BACKGROUND OF THE INVENTION
Under the consideration of economics and productivity, an encapsulating material for currently semiconductor devices is mostly an epoxy-based resin composition. To insure the use safety, electronic parts for the semiconductor are required to meet a flame retarding specification regulated by the UL. The approach to attain the flame retarding specification is addition of halogen-containing epoxy resin and diantimony trioxide as a flame retarding assistant into epoxy resin compositions for encapsulating electronic parts. However, it is known that such flame retarding assistants are harmful to human and animal. For example, diantimony trioxide has been classified a cancerous material while an epoxy resin containing halogen such as bromine will produce corrosive bromine free radical and hydrogen bromide during burning. Also, an aryl compound containing high content bromine will produce toxic brominated furanes and brominated dioxins compounds. Such toxic materials have adverse effects to human, animal and environment. Thus, it is eagerly required to semiconductor manufacture for developing a novel epoxy resin without halogen neither diantimony trioxide to resolve the problems associated with the use of halogen-containing epoxy resin and diantimony trioxide.
For flame retarding resins, a phosphorous-containing compound is widely used as a new generation flame retarding agent. Among others, it commonly uses phosphorus or phosphorous-containing organic compound (e.g. triphenyl phosphate (TPP), tricresyl phosphate (TCP), and phosphoric acid etc.,) as a flame retarding agent instead of halogen-containing flame retarding agents to improve flame retarding characteristic of thermosetting resin. By using such a conventional phosphorous-containing compound as a flame retarding agent, it is required to incorporate such a flame retarding agent in a large amount into epoxy resin composition formulations due to its poor flame retardant effect. It will cause lowering of relative amount of the epoxy resin and the curing agent contained in the formulation so that the performances of the epoxy formulation will decrease. Moreover, since the conventional phosphorous-containing compound has low molecular weight and in turn exhibits a high migration, it will directly affect the characteristics of the resulting epoxy resin, e.g. electrical property and strength, etc., and will make it impracticable. For example, Taiwan Patent Publication No. 339353 discloses the use of red phosphorous in stead of halogen and antimony compound as a flame retarding agent. However, when the article prepared from the resin containing red phosphorous is boiled at an elevated temperature, the red phosphorous contained therein will be hydrolyzed resulting in hazardous operation and then affect adversely on the process and product.
Recently, under the considerations of environmental protection and safety, a reactive type resin flame retarding agent is used to substitute for currently used flame retarding agent, especially a phosphorous-containing flame retarding agent is used in stead of brominated epoxy resin. For example, Japanese Patent Unexamined Publication Hei 9-235449 discloses the use a phosphorous-containing epoxy resin in stead of halogen and antimony compound as a flame retarding agent. The patent publication claims that the composition having the phosphorous-containing epoxy resin has improved fire resistance and would not produce dioxine during burning. However, since such additive type and reactive type phosphorous-containing substances possess low phosphorous content, the composition containing such phosphorous-containing substance exhibits poor fire resistance. To attain desired flame retarding effect, it is required to incorporating such a flame retarding agent in a large amount into epoxy resin composition formulations. It will cause lowering of relative amount of the epoxy resin and the curing agent contained in the formulation so that the performances of the epoxy formulation will decrease.
To replace of a halogen-containing compound and antimony-containing compound, it has recently developed a nitrogen- or phosphorous-containing compound as flame retarding agent. Most commonly used nitrogen-containing compound includes, for example, melamine, DICY, triazine-containing cyanate, etc. The phosphorous-containing compound includes reactive type phosphorous-containing compound having reactive functional group, and non-reactive type phosphorous-containing compound. The reactive type phosphorous-containing compound possesses a better heat stability than the non-reactive type phosphorous-containing compound since the reactive functional group contained therein could react with the other components to form a bond between therein. Therefore, the reactive type phosphorous-containing compound becomes a developed main stream in the future.
The most commonly used reactive type phosphorous-containing compound is a straight chain phosphorous-containing compound. Such a straight chain phosphorous-containing compound have a group of —O—P—O— in the main chain, it exhibits poor fire resistance than the flame retarding agent with or without containing halogen. Also, the straight chain reactive type phosphorous-containing compound or non-reactive type phosphorous-containing compound has poor processing ability.
To overcome the disadvantages associated with the current semiconductor encapsulating technique, the present inventors have investigated on epoxy resin and then developed a modified phosphorous-containing epoxy resin. Thus the present invention is completed.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The present invention relates to a phosphorous-containing flame retarding epoxy resin and their composition comprising the nitrogen-containing flame retarding epoxy resin. More specifically, the present invention relates to a flame retarding epoxy resin having a pendent phosphorous-containing functional group and their composition comprising the nitrogen-containing flame retarding epoxy resin.
The present invention relates to a phosphorous-containing epoxy resin of the following formula:
wherein R represents a C1-6 alkylene group;
a represents an integral number of from 1 to 10;
b represents an integral number of from 0 to 10;
X represents a group of formula —(O—CH
2
—CH(OH)—CH
2
-O—M—)
y
—, in which y represents an integral number of from 0 to 20; and M represents a group selected from the following groups (E1)□(E2), and (E3):
wherein R
3
represents a C
1-6
alkyl group; A represents a chemical bond, —O—, —S—, —SO
2
—, —CO—, C
1-6
alkylene group, or a group of the following formula:
wherein R
1
represents a hydrogen atom or a C
1-6
alkyl group, d represents an integral number of from 0 to 6, R
2
s are the same or different and represent a hydrogen atom or a group of the following formula:
in which R
1
is the same as defined above;
in which R
1
is the same as defined above; m and n are the same or different and represent an integral number of from 0 to 3;
Ar
1
and Ar
2
are the same or different and represent a group selected from the following formulae (E3) or (E4):
wherein R
1
, m, and n are the same as defined above.
The phosphorous-containing epoxy resin of the present invention is obtained from the steps of addition reacting a phosphorous-containing compound having the following formula:
(in which Hal represents a halogen atom, e.g. fluorine, chlorine, bromine, or iodine, etc.) with aldehydes having reactive functional group, then condensing reacting with phenols, and finally reacting with epihalohydrins.
As the phosphorous atom is located on the side chain o
Chen Chih-Fu
Chen Hong-Hsing
Hwang Kuen-Yuan
Aylward D.
Chang Chung Plastics Co., Ltd.
Dawson Robert
Kramsky Elliott N.
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