US4681718A — Method of fabricating composite or encapsulated a…

Claim 1

Independent Claim 294 words

A method for forming a resin based filler reinforced composite article which comprises the steps of: (a) providing a rigid mold having a cavity therein and an opening in one surface of said mold and communicating with said cavity; (b) providing a chamber for containing said mold and for applying heat and varying pressures to said cavity of said mold; (c) heating said chamber to a predetermined temperature and maintaining said temperature in said chamber; (d) loading a quantity of a particulate filler material in said cavity of said mold; (e) loading said mold containing said filler into said heated chamber; (f) filling the mold cavity with a low viscosity heat curable themosetting resin which cures at said predetermined temperature; (g) evacuating the mold cavity to a subatmospheric pressure within the range of about 1 to 200 millimeters of mercury for about 1 to 5 minutes, to impose a vacuum on the mold to thereby impregnate the filler material with the resin, degas the mold contents, and expand any remaining voids in the resin; (h) releasing the vacuum to atmospheric pressure to collapse any gas bubbles remaining in the mold contents; (i) applying a superatmospheric pressure within the range of about 100, to 1000 pounds per square inch (about 6.90×10 5 to 6.90×10 6 pascals) for about 1 to 2 hours, to the mold to burst any said gas bubbles and cause the heat curable resin to compact and encapsulate particles of the filler loaded in the mold, the temperature and the superatmospheric pressure being maintained for a time sufficient to partially cure the resin and form a unitary structure; (j) ejecting the structure from the mold cavity; and (k) subjecting the ejected structure to a further heating cycle to completely cure the resin.

Claim 2

Independent Claim 294 words

A method for forming a resin based filler reinforced composite article which comprises the steps of: (a) providing a rigid mold having a cavity therein and an opening in one surface of said mold and communicating with said cavity; (b) providing a chamber for containing said mold and for applying heat and varying pressures to said cavity of said mold; (c) heating said chamber to a predetermined temperature and maintaining said temperature in said chamber; (d) loading a quantity of a particulate filler material in said cavity of said mold; (e) loading said mold containing said filler into said heated chamber; (f) filling the mold cavity with a low viscosity heat curable themosetting resin which cures at said predetermined temperature; (g) evacuating the mold cavity to a subatmospheric pressure within the range of about 1 to 200 millimeters of mercury for about 1 to 5 minutes, to impose a vacuum on the mold to thereby impregnate the filler material with the resin, degas the mold contents, and expand any remaining voids in the resin; (h) releasing the vacuum to atmospheric pressure to collapse any gas bubbles remaining in the mold contents; (i) applying a superatmospheric pressure within the range of about 100, to 1000 pounds per square inch (about 6.90×10 5 to 6.90×10 6 pascals) for about 1 to 2 hours, to the mold to burst any said gas bubbles and cause the heat curable resin to compact and encapsulate particles of the filler loaded in the mold, the temperature and the superatmospheric pressure being maintained for a time sufficient to partially cure the resin and form a unitary structure; (j) ejecting the structure from the mold cavity; and (k) subjecting the ejected structure to a further heating cycle to completely cure the resin.

Claim 3

Dependent Claim 27 words

The method of claim 1 wherein the heat curable resin is selected from the group consisting of an epoxy resin, a polyimide resin and a bismaleimide resin.

Claim 4

Dependent Claim 29 words

The method of claim 1 wherein the heat curable resin is an epoxy resin comprising a mixture of a polyglycidyl aromatic amine and a polycarboxylic acid anhydride curing agent.

Claim 5

Dependent Claim 24 words

The method of claim 3 wherein the polyglycidyl aromatic amine is diglycidyl orthotoluidine and the polycarboxylic acid anhydride curing agent is nadic methyl anhydride.

Claim 6

Dependent Claim 23 words

The method of claim 3 wherein the polyglycidyl aromatic amine is diglycidyl aniline and the polycarboxylic anhydride curing agent is methyl tetrahydrophthalic anhydride.

Claim 7

Dependent Claim 32 words

The method of claim 3 wherein the structure ejected from the mold is heated at about 250° (121° C.) to about 350° F. (177° C.) for about 1.25 to about 4 hours.

Claim 8

Dependent Claim 52 words

The method of claim 1 wherein the filler material comprises fibers and hollow microspheres, the fibers being formed of a material selected from the group consisting of graphite, glass, carbon, ceramic, and polyamide, and the microspheres being formed of a material selected from the group consisting of glass, silica, phenolic and carbon.

Claim 9

Dependent Claim 26 words

The method of claim 7 wherein said fibers comprise whiskers formed of a material selected from the group consisting of silicon carbide, silicon nitride, and sapphire.

Claim 10

Dependent Claim 26 words

The method of claim 3 wherein the mold is heated to a curing temperature of about 150° F. (66° C.) to about 250° F. (121° C.).

Claim 11

Dependent Claim 28 words

The method of claim 1 wherein the heat curable resin is an epoxy resin and the completely cured epoxy resin unitary structure is subsequently electrolessly plated with copper.

Claim 12

Dependent Claim 29 words

The method of claim 1 wherein the heat curable resin is an epoxy resin and the time sufficient to partially cure the resin is about 1 to 2 hours.

Claim 13

Dependent Claim 78 words

The method set forth in claim 1 which further includes: (a') providing a second or subsequent rigid mold; (b') loading a second or subsequent quantity of particulate filler in said cavity of said second or subsequent mold; (c') following said ejecting of step "j", repeating steps "e" through "k" with said second or subsequent mold, whereby said method is performed in cyclic fashion to form continuously in sequence a plurality of said resin based filler reinforced composite articles.

Claim 14

Dependent Claim 38 words

The method set forth in claim 1 wherein prior to said filling of step "f", said chamber is evacuated to a pressure of about one millimeter of mercury or less and subsequently said filling occurs under said vacuum.

Claim 15

Dependent Claim 40 words

The method of claim 1 wherein said filler material is loaded in the mold cavity concurrent with the filling of the mold cavity with the resin and prior to the loading of said mold into said chamber in step "e".

Claim 16

Independent Claim 281 words

A method for encapsulating an electrical component which comprises the steps of: (a) providing a rigid mold having a cavity therein and an opening in one surface of said mold and communicating with said cavity; (b) providing a chamber for containing said mold and for applying heat and varying pressures to said cavity of said mold; (c) heating said chamber to a predetermined temperature and maintaining said temperature in said chamber; (d) loading the component in said cavity of said mold; (e) loading said mold containing said component into said heated chamber; (f) filling the mold cavity with a low viscosity heat curable thermosetting resin which cures at said predetermined temperature; (g) evacuating the mold cavity to a subatmospheric pressure within the range of about 1 to 4 millimeters of mercury for about 1 to 5 minutes, to impose a vacuum on the mold to thereby impregnate the component with the resin, degas the mold contents, and expand any remaining voids in the resin; (h) releasing the vacuum to atmospheric pressure to collapse any gas bubbles remaining in the mold contents; (i) applying a superatmospheric pressure within the range of about 50 to 100 pounds per square inch (about 3.45×10 5 to 6.90×10 5 pascals) for about 30 minutes to 3 hours, to the mold to burst any said gas bubbles and cause the heat curable resin to encapsulate the component loaded in the mold, the temperature and the superatmospheric pressure being maintained for a time sufficient to partially cure the resin and form a unitary structure; (j) ejecting the structure from the mold cavity; and (k) subjecting the ejected structure to a further heating cycle to completely cure the resin.

Claim 17

Independent Claim 281 words

A method for encapsulating an electrical component which comprises the steps of: (a) providing a rigid mold having a cavity therein and an opening in one surface of said mold and communicating with said cavity; (b) providing a chamber for containing said mold and for applying heat and varying pressures to said cavity of said mold; (c) heating said chamber to a predetermined temperature and maintaining said temperature in said chamber; (d) loading the component in said cavity of said mold; (e) loading said mold containing said component into said heated chamber; (f) filling the mold cavity with a low viscosity heat curable thermosetting resin which cures at said predetermined temperature; (g) evacuating the mold cavity to a subatmospheric pressure within the range of about 1 to 4 millimeters of mercury for about 1 to 5 minutes, to impose a vacuum on the mold to thereby impregnate the component with the resin, degas the mold contents, and expand any remaining voids in the resin; (h) releasing the vacuum to atmospheric pressure to collapse any gas bubbles remaining in the mold contents; (i) applying a superatmospheric pressure within the range of about 50 to 100 pounds per square inch (about 3.45×10 5 to 6.90×10 5 pascals) for about 30 minutes to 3 hours, to the mold to burst any said gas bubbles and cause the heat curable resin to encapsulate the component loaded in the mold, the temperature and the superatmospheric pressure being maintained for a time sufficient to partially cure the resin and form a unitary structure; (j) ejecting the structure from the mold cavity; and (k) subjecting the ejected structure to a further heating cycle to completely cure the resin.

Claim 18

Dependent Claim 65 words

The method set forth in claim 15 which further includes subsequent to said ejecting of step "j", loading a second or subsequent component into said mold cavity through said opening in said mold and repeating steps "e" through "k" for said second or subsequent component whereby said method is performed in cyclic fashion to form continuously in sequence a plurality of encapsulated said electrical components.

Claim 19

Dependent Claim 38 words

The method set forth in claim 15 wherein prior to said filling of step "f", said chamber is evacuated to a pressure of about one millimeter of mercury or less and subsequently said filling occurs under said vacuum.

Claim 20

Dependent Claim 30 words

The method of claim 15 wherein the heat curable resin is an epoxy resin and the time sufficient to partially cure the resin is about 0.5 to about 3 hours.

Claim 21

Dependent Claim 27 words

The method of claim 15 wherein the heat curable resin is selected from the group consisting of an epoxy resin, a polymide resin and a bismaleimide resin.

Claim 22

Dependent Claim 29 words

The method of claim 15 wherein the heat curable resin is an epoxy resin comprising a mixture of a polyglycidyl aromatic amine and a polycarboxylic acid anhydride curing agent.

Claim 23

Dependent Claim 24 words

The method of claim 20 wherein the polyglycidyl aromatic amine is diglycidyl orthotoluidine and the polycarboxylic acid anhydride curing agent is nadic methyl anhydride.

Claim 24

Dependent Claim 23 words

The method of claim 20 wherein the polyglycidyl aromatic amine is diglycidyl aniline and the polycarboxylic anhydride curing agent is methyl tetrahydrophthalic anhydride.

Claim 25

Dependent Claim 32 words

The method of claim 20 wherein the structure ejected from the mold is heated at about 250° (121° C.) to about 350° F. (177° C.) for about 1.25 to about 4 hours.

Claim 26

Dependent Claim 26 words

The method of claim 20 wherein the mold is heated to a curing temperature of about 150° F. (66° C.) to about 250° F. (121° C.).

Claim 27

Dependent Claim 53 words

The method of claim 15 wherein prior to loading the component in the mold cavity, a predetermined quantity of filler material is loaded in the mold cavity whereby the unitary structure comprises the electrical component encapsulated and impregnated with the resin and coated with a layer of a resin based filler reinforced composite.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1990-07-20	1991-01-19	1991-07-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1994-07-20	1995-01-19	1995-07-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1998-07-20	1999-01-19	1999-07-21	$7700.00	Window Closed / Lapsed

Method of fabricating composite or encapsulated articles

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