EP0092578B1
Expired / Lapsed
EP
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Erasable inks containing thermoplastic block copolymers
Assignee: Gillette Co LLC
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Filing: 1982-10-22
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Granted: 1989-09-20
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Expires: 2002-10-22
Abstract
Abstract An erasable ink containing a thermoplastic block copolymer, pigment particles, and a solvent. In a preferred embodiment, an erasable ink requiring little or no pressurization is provided by employing a mixture of radial and linear block copolymers and a mixed solvent system falling within a specific range of solubility parameter. Polybutene and poly-alpha-methylstyrene are preferred additives to decrease smearing tendency.
Inventors
- 👤 Edward John Ferguson
- 👤 Iii Robert Franklin Farmer
- 👤 Diane A. Riesgraf
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 22:52
CPC Classifications
C; C09; C09D; C09D11/00; C09D11/16; C09D11/18; C09D153/00; C09D153/02
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
120 words
An erasable ink for use in a ball-point pen and comprising a pigmented organic solvent solution of a polymeric material characterized by said solution including a thermoplastic block copolymer having glassy A (thermoplastic) blocks and B (rubbery) blocks having an arrangement consisting of ABA, (AB) n X, or (―AB)― wherein X is an organic or inorganic connecting molecule with a functionality of 2-4 and n is a number corresponding to the functionality of X, and said thermoplastic blocks consist of polystyrene blocks, said rubbery blocks consist of polybutadiene, polyisoprene or polyethylene-polybutylene blocks, the ratio of said rubbery blocks to said thermoplastic blocks is from 60:40 to 90:10, and the solubility parameter of said organic solvent is from 7 to 10.5.
Claim 2
Dependent Claim
120 words
An erasable ink for use in a ball-point pen and comprising a pigmented organic solvent solution of a polymeric material characterized by said solution including a thermoplastic block copolymer having glassy A (thermoplastic) blocks and B (rubbery) blocks having an arrangement consisting of ABA, (AB) n X, or (―AB)― wherein X is an organic or inorganic connecting molecule with a functionality of 2-4 and n is a number corresponding to the functionality of X, and said thermoplastic blocks consist of polystyrene blocks, said rubbery blocks consist of polybutadiene, polyisoprene or polyethylene-polybutylene blocks, the ratio of said rubbery blocks to said thermoplastic blocks is from 60:40 to 90:10, and the solubility parameter of said organic solvent is from 7 to 10.5.
Claim 3
Dependent Claim
20 words
An ink according to claim 1, characterized in that the block copolymer is a styrene-isoprene-styrene, styrene-butadiene-styrene, or styrene-ethylene/butylene-styrene block copolymer.
Claim 4
Dependent Claim
20 words
An ink according to claim 2, characterized in that said block copolymer is a linear styrene-isoprene-styrene or styrene-butadiene-styrene block copolymer.
Claim 5
Dependent Claim
18 words
An ink according to claim 2, characterized in that the ratio of styrene to isoprene is about 30:70.
Claim 6
Dependent Claim
18 words
An ink according to claim 2, characterized in that the ratio of styrene to butadiene is about 14:86.
Claim 7
Dependent Claim
27 words
An ink according to anyone of claims 1 to 5, characterized in that the thermoplastic block copolymer is a mixture of radial and linear thermoplastic block copolymers.
Claim 8
Dependent Claim
27 words
An ink according to claim 6, characterized in that the ratio of linear to radial block copolymer is between 1:1 and 1:7, and preferably is about 1:3.
Claim 9
Dependent Claim
21 words
An ink according to claim 6 or 7, characterized in that each of said block copolymers is a styrene-isoprene-styrene block copolymer.
Claim 10
Dependent Claim
27 words
An ink according to any one of the preceding claims, characterized in that the block copolymer is present in a concentration by weight between 10% and 30%.
Claim 11
Dependent Claim
20 words
An ink according to any one of the preceding claims, characterized in that particles of pigment are dispersed in dioctylphthalate.
Claim 12
Dependent Claim
23 words
An ink according to any one of the preceding claims, characterized in that the solvent has a solubility parameter between 8.1 and 8.7.
Claim 13
Dependent Claim
19 words
An ink according to any one of the preceding claims, characterized in that said solvent is toluene or hexane.
Claim 14
Dependent Claim
17 words
An ink according to any one of the preceding claims, characterized by additionally comprising polybutene and/or poly-alpha-methylstyrene.
Claim 15
Dependent Claim
28 words
An ink according to claim 13, characterized in that polybutene is present at less than 10% by weight, or poly-alpha-methylstyrene is present at less than 10% by weight.
Claim 16
Dependent Claim
25 words
An ink according to any one of the preceding claims, characterized in that the concentration of particles of pigment is less than 9% by weight.
Claim 17
Dependent Claim
54 words
An ink according to any one of the preceding claims, characterized by comprising between 10% and 30% by weight of the thermoplastic block copolymer, less than the critical pigment concentration of particles of pigment, and between 71% to 85% by weight of a low volatility solvent having a solubility parameter between 8.1 and 8.7.
Claim 18
Dependent Claim
30 words
An ink according to claim 16, characterized in that the solvent has a volatility of not greater than 10 on a scale where butyl acetate has a volatility of 100.
Claim 19
Dependent Claim
50 words
An ink according to claim 16, characterized in that the solvent is a mixed solvent system with a first solvent of the mixed solvent system having a solubility parameter between 7.2 and 7.8, and a second solvent of the mixed solvent system having a solubility parameter between 8.7 and 8.9.
References Cited (Backward Citations)
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