Plastic and nonmetallic article shaping or treating: processes – Direct application of electrical or wave energy to work – Polymerizing – cross-linking – or curing
Reexamination Certificate
2000-04-24
2001-12-25
Ortiz, Angela (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Direct application of electrical or wave energy to work
Polymerizing, cross-linking, or curing
C264S272190, C264S272200, C029S605000
Reexamination Certificate
active
06332998
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a molding composition, molded parts made therefrom, and a method of manufacturing molded parts.
BACKGROUND OF THE INVENTION
Hitherto, the method of manufacturing molded parts buried in a thermosetting resin involves the steps of:
(1) putting parts to be buried into a heated die,
(2) filling the die containing the parts with a curable thermosetting resin molding material by either an injection method or a transfer method to cover the parts with the resin,
(3) curing the thermosetting resin in the die by heating to a temperature above the reaction starting temperature, and
(4) finally completely curing to finish the curing reaction, and removing the molded parts from the die.
In order to shorten the curing time and enhance productivity, it is necessary to raise the temperature of the molding material as promptly as possible above the reaction starting temperature. To this purpose, by preliminarily heating either the parts to be buried or the molding material, one hopes to decrease the curing time.
In the known conventional method of preliminarily heating the parts to be buried, when the parts are heated to a temperature close to the reaction starting temperature of the thermosetting resin, curing starts during the step of injecting the mold into the die in which the heated parts are placed. As such, the molding material is not completely injected into the die, or the molding material is not completely charged into the parts. Or, the cured molded parts are cracked, and complete molded parts are not obtained. Thus, the preliminary heating temperature of the parts to be buried cannot be raised too high.
Moreover, the reaction starting temperature and the curing time of the thermosetting resin depend greatly on the type of polymerization initiating agent, such as a peroxide, added to the resin. Hence the curing time can be controlled by selecting the type of polymerization initiating agent. However, the polymerization initiating agent to decrease the curing time generally causes a simultaneous drop in the reaction starting temperature. This means that the storage period of the molding material is shorter, and the storage stability of the molding material is inferior.
It is hence an object of the present invention to provide a molding composition having enhanced productivity and a method of manufacturing molded parts from that molding composition.
SUMMARY OF THE INVENTION
The molding composition of the present invention includes:
an unsaturated alkyd resin, and
a crosslinking monomer to be crosslinked to the unsaturated alkyd resin,
in which the crosslinking monomer includes a first crosslinking monomer having a [C═C] group, a [—CO
2
—] group and a [—OH] group. These groups are, respectively, an ethylenically unsaturated group, a carboxyl group, and a hydroxy group.
A molded part of the present invention includes:
(a) a cured resin resulting from curing a molding composition comprising
(1) an unsaturated alkyd resin, and
(2) a crosslinking monomer to be crosslinked to the unsaturated alkyd resin, in which the crosslinking monomer includes a first crosslinking monomer having a [C═C] group, a [—CO
2
—] group, and a [—OH] group, and
(b) an electronic component covered with the cured resin (a).
A method of manufacturing a molded part of the present invention from the corresponding molding composition comprises the following steps:
(a) covering with a molding composition the outside of an electronic component that can be heated,
(b) feeding power to the electronic component to generate heat in the electronic component, and
(c) curing the molding composition using the heat generated in the electronic component.
Preferably, the first crosslinking monomer is at least one of 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate.
Preferably, the electronic component has a coil formed by winding a conductive wire, and the coil generates heat as power is fed to the coil.
In this construction the molding composition curing time is decreased. Moreover, the productivity of the manufacture of molded parts is enhanced.
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Onishi Hiroshi
Terada Takahiko
Yamagata Yoshikazu
Yamashita Fumitoshi
Matsushita Electric - Industrial Co., Ltd.
Ortiz Angela
Parkhurst & Wendel LLP
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