Abstract Carbon paper coatings of the type embodying a vinyl resin matrix which embraces a pigment-carrying nonvolatile liquid exudable under pressure to make a mark on a copy sheet, are provided. The coating is of such character that pigments having a high agglomerative tendency, especially magnetic pigments such as iron oxide, can be used and still be carried properly from the layer along with the liquid vehicle when pressure is applied. In the case of magnetic pigments this makes it possible to provide marks which embody sufficient pigment to give appropriate signal strength for scanning. The result is achieved by including in the mixture an amine type wetting agent, and by providing as a portion of the volatile vehicle used to render the mixture coatable a pair of control solvents of different types. The control solvents are one of the ketone type and the other of a nonketone type (such as ethyl acetate, 2-nitro propane, or equivalent). The optimum ratio between the control solvents is usually between about 1:2 and about 1:1.
A marking element as set forth in claim 1 in which the amine type wetting agent is tallow 1,3propylene diamine dioleate.
Claim 2
Dependent Claim
66 words
A marking element as set forth in claim 1 in which the layer of marking composition is the dried residue of a mixture embodying the ingredients stated in claim 1 together with a volatile liquid vehicle comprising a ketone and a nonketonic solvent of the ethyl acetate-2 nitropropane class, and in which the volatile vehicle contains these ingredients in a ratio of between 1:2 and 1:1.
Claim 3
Dependent Claim
32 words
A marking element as set forth in claim 3 in which the dried layer is the result of treating the undried coating by impinging on its exposed surface a stream of air.
Claim 4
Dependent Claim
21 words
A marking element as set forth in claim 4 in which the amine type wetting agent is tallow 1,3-propylene diamine dioleate.
Claim 5
Dependent Claim
75 words
A marking element as set forth in claim 5 in which the softener is castor oil and is present in an amount equal to about 10 parts by weight; the magnetic iron oxide pigment is present in an amount equal to about 27 parts by weight; and the wetting agent is present in an amount equal to about 2.8 parts by weight of which at least 1 part by weight is tallow 1,3-propylene diamine dioleate.
Claim 6
Independent Claim
123 words
The method of preparing a pressure sensitive ink-releasing element which comprises coating a foundation with a thin layer of a composition consisting essentially of: 10 parts by weight of a substantially nonpressure transferable thermoplastic resin base of a sofT vinyl chloride-acetate copolymer or mixture of such copolymers; 7 to 15 parts by weight of a nonvolatile liquid softener, immiscible with the base; 10 to 40 parts by weight of an agglomerative magnetic pigment, 0.1 to 5 parts by weight of a wetting agent, a substantial share of which is a wetting agent of the amine type; and a volatile liquid vehicle which is a solvent for the base and miscible with the softener in an amount sufficient to render the mixture readily coatable.
Claim 7
Dependent Claim
37 words
The method of preparing a pressure sensitive ink-releasing element as set forth in claim 7 in which the setting of the layer is abetted by causing a stream of air to impinge on the exposed surface thereof.