US4407985A — Method of making and improved compositions for an…

Claim 1

Independent Claim 165 words

In a ball point writing instrument containing an ink capable of depositing a trace on an absorbent, paper-like writing surface having minute voids therein, said trace being characterized by initial erasability thereof by ordinary pencil erasers and the capability of developing permanence over a period of time, said ink comprising pigment, a polar elastomer, said polar elastomer having a selected molecular weight range of about 90,000 to 1,000,000 and a selected Mooney viscosity range of about 15 to 60 and requiring no mastication for use in said ink, and a solvent system, said solvent system comprising a volatile component having a boiling point less than about 180° C. and an essentially non-volatile component which includes pigment vehicle having a boiling point greater than about 300° C. and low viscosity plasticizer having a boiling point greater than 180° C. but less than 300° C., the solvent system being present in amount sufficient to impart a final ink viscosity in the range of about 1.5 million cps.

Claim 2

Dependent Claim 165 words

In a ball point writing instrument containing an ink capable of depositing a trace on an absorbent, paper-like writing surface having minute voids therein, said trace being characterized by initial erasability thereof by ordinary pencil erasers and the capability of developing permanence over a period of time, said ink comprising pigment, a polar elastomer, said polar elastomer having a selected molecular weight range of about 90,000 to 1,000,000 and a selected Mooney viscosity range of about 15 to 60 and requiring no mastication for use in said ink, and a solvent system, said solvent system comprising a volatile component having a boiling point less than about 180° C. and an essentially non-volatile component which includes pigment vehicle having a boiling point greater than about 300° C. and low viscosity plasticizer having a boiling point greater than 180° C. but less than 300° C., the solvent system being present in amount sufficient to impart a final ink viscosity in the range of about 1.5 million cps.

Claim 3

Dependent Claim 33 words

In a ball point writing instrument as defined in claim 1 wherein said polar elastomer is selected from the group consisting of butadiene/acrylonitrile copolymer rubbers and vinyl acetate/ethylene copolymer rubbers and mixtures thereof.

Claim 4

Dependent Claim 49 words

In a ball point writing instrument as defined in claim 1 wherein the pigment vehicle is present in about the same weight percentage of the ink composition as is the pigment component and these are used to provide a pigment paste which contains about 50/50 pigment and pigment vehicle.

Claim 5

Dependent Claim 25 words

In a ball point writing instrument as defined in claim 1 wherein said polar elastomer is present in the range of about 14-25% by weight.

Claim 6

Dependent Claim 25 words

In a ball point writing instrument as defined in claim 1 wherein said volatile component is present in the range of about 39-44% by weight.

Claim 7

Dependent Claim 26 words

In a ball point writing instrument as defined in claim 1 wherein said low viscosity plasticizer is present in the range of about 9-27% by weight.

Claim 8

Dependent Claim 26 words

In a ball point writing instrument as defined in claim 1 wherein said low viscosity plasticizer has a viscosity of about 2 cps at 25° C.

Claim 9

Independent Claim 224 words

The method of making an ink composition for ball point pen writing instrument, which composition when applied by the pen as a trace on a porous substrate such as paper will exhibit the characteristic of initial erasability by ordinary pencil eraser but developing indelibility with time, which comprises the steps of: forming an elastomer solution without pre-mastication of the elastomer and in the absence of milling by selecting a polar elastomer and contacting it, with stirring, with a volatile solvent for the polar elastomer until the polar elastomer swells in the volatile solvent and forms a smooth, homogeneous single phase, the solvent having a boiling point at atmospheric pressure of less than 180° C.; and adding to said single phase, with mixing, a trace intensity colorant amount of pigment having a particle size of less than about 5 microns, a writing smoothness and viscosity adjusting amount of an essentially non-volatile solvent component having a boiling point at atmospheric pressure of greater than 300° C., and a viscosity adjusting and indelibility-with-time controlling amount of a low viscosity, essentially non-volatile solvent component having a boiling point at atmospheric pressure which is within the range of 180°-300° C., and continuing such mixing until a smooth, homogeneous final ink composition having the consistency of a relatively loose-structured gel and a viscosity of about 1.5 million cps is attained.

Claim 10

Independent Claim 224 words

The method of making an ink composition for ball point pen writing instrument, which composition when applied by the pen as a trace on a porous substrate such as paper will exhibit the characteristic of initial erasability by ordinary pencil eraser but developing indelibility with time, which comprises the steps of: forming an elastomer solution without pre-mastication of the elastomer and in the absence of milling by selecting a polar elastomer and contacting it, with stirring, with a volatile solvent for the polar elastomer until the polar elastomer swells in the volatile solvent and forms a smooth, homogeneous single phase, the solvent having a boiling point at atmospheric pressure of less than 180° C.; and adding to said single phase, with mixing, a trace intensity colorant amount of pigment having a particle size of less than about 5 microns, a writing smoothness and viscosity adjusting amount of an essentially non-volatile solvent component having a boiling point at atmospheric pressure of greater than 300° C., and a viscosity adjusting and indelibility-with-time controlling amount of a low viscosity, essentially non-volatile solvent component having a boiling point at atmospheric pressure which is within the range of 180°-300° C., and continuing such mixing until a smooth, homogeneous final ink composition having the consistency of a relatively loose-structured gel and a viscosity of about 1.5 million cps is attained.

Claim 11

Dependent Claim 213 words

In a pressurized ball point writing instrument containing an ink capable of depositing a trace on an absorbent, paper-like writing surface having minute voids therein, said trace being characterized by initial erasability thereof by ordinary pencil erasers and the capability of developing permanence over a period of time, said ink having the consistency of a relatively loose-structured gel and comprising pigment, a polar elastomer having a Mooney viscosity of about 15-60 and a molecular weight in the range of about 90,000-1,000,000 and a solvent system; said solvent system comprising a volatile component having a boiling point less than about 180° C. in which the volatile component is a solvent for the polar elastomer and is present in an amount sufficient, in the presence of the polar elastomer alone, to cause the polar elastomer to swell therein and form a smooth homogeneous single phase, and an essentially non-volatile component which includes pigment vehicle having a boiling point greater than 300° C. and low viscosity plasticizer having a boiling point greater than 180° C. but less than 300° C.; said pigment, polar elastomer and solvent system cooperating to produce said loose-structured gel consistency and being present in such relative amounts as to impart a viscosity in the order of 1.5 million cps to the ink.

Claim 12

Dependent Claim 213 words

In a pressurized ball point writing instrument containing an ink capable of depositing a trace on an absorbent, paper-like writing surface having minute voids therein, said trace being characterized by initial erasability thereof by ordinary pencil erasers and the capability of developing permanence over a period of time, said ink having the consistency of a relatively loose-structured gel and comprising pigment, a polar elastomer having a Mooney viscosity of about 15-60 and a molecular weight in the range of about 90,000-1,000,000 and a solvent system; said solvent system comprising a volatile component having a boiling point less than about 180° C. in which the volatile component is a solvent for the polar elastomer and is present in an amount sufficient, in the presence of the polar elastomer alone, to cause the polar elastomer to swell therein and form a smooth homogeneous single phase, and an essentially non-volatile component which includes pigment vehicle having a boiling point greater than 300° C. and low viscosity plasticizer having a boiling point greater than 180° C. but less than 300° C.; said pigment, polar elastomer and solvent system cooperating to produce said loose-structured gel consistency and being present in such relative amounts as to impart a viscosity in the order of 1.5 million cps to the ink.

Claim 13

Dependent Claim 35 words

In a pressurized ball point pen writing instrument as defined in claim 9 wherein said polar elastomer is selected from the group consisting of butadiene acrylonitrile copolymer rubbers, vinyl acetate/ethylene copolymer rubbers and mixtures thereof.

Claim 14

Dependent Claim 29 words

In a pressurized ball point pen writing instrument as defined in claim 10 wherein said polar elastomer is present in amount of about 14-25% by weight of the ink.

Claim 15

Dependent Claim 29 words

In a pressurized ball point pen writing instrument as defined in claim 11 wherein said volatile component is present in amount of about 12-35% by weight of the ink.

Claim 16

Dependent Claim 30 words

In a pressurized ball point pen writing instrument as defined in claim 12 wherein said low viscosity plasticizer is present in amount of about 9-27% by weight of the ink.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1986-10-03	1987-04-04	1987-10-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1990-10-03	1991-04-04	1991-10-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1994-10-03	1995-04-04	1995-10-04	$7700.00	Window Closed / Lapsed

Method of making and improved compositions for an initially erasable ink for a ball point writing instrument

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