US2992121A

US2992121A - Thermosensitive colouring materials

Info

Publication number: US2992121A
Authority: US
Inventors: Francis Frederick George; Seaward John Albert
Original assignee: Caribonum Ltd
Current assignee: Caribonum Ltd
Priority date: 1957-05-16
Filing date: 1958-05-07
Publication date: 1961-07-11
Anticipated expiration: 1978-07-11
Also published as: GB842655A

Description

- THERMOSENSITIVE OLOURING MATERIAL Frederick George Francis, Old Southgate, London, and 'fJohniAlbert ,Seaward, Enfield, England, assiguors to Caribonum ll'imitemLondon, England, a British com '2 1:10 'DraWiBg'.'- Filed May 7,1958, Ser. No. 733,469 Cla1ms-pr10rity, appli ation Gre'at Britain May 16, 1 957- 1; .f'. 1(Cl.. 106-1-2'3) presentinvention relatesjtocolouring materials and is-concerned particularly, but not exclusively, with colouring materials employed in the manufacture of inks, typewriter and other inked ribbons and carbon papers.

Copying processesare 'known, which make use of thermo-sensitive paper or other sheet material. In such processes, 'a sheet of thermo-sensitive material, such as a sheet of paper; coated with one or, more layers of a thermo sensitive composition which produces a distinctive colouration in those areas; subjected to a suitable increase in temperature, is placed in contact with and above the printed, typewritten or other material to be copied and the sheets, are then irradiated with infra-red rays. This generates a heat pattern inv the copy sheet in accordance with the characters or other markings on the material to 2,992,121 2 Patented July 11,1961

matic-coloured, isused hereinafterand. in the appended claims to mean such. coloured, non-blackpigments or othercolouring materials.

gAcoording to the invention, a chromatic-coloured ink composition is provided,-.which is adapted to produce coloured written copy matter capable of'being copied by a thermosensitive copyingprocess, which ink composition consists essentially .of an oil-containing vehicle, at least one chromatic-coloured colouring material in an amount of from 15% to 30% by weight of the ink composition and finely-divided antimony in an amount sufficient to give "satisfactory thermosensitive copy by imparting infrared absorptive properties to the ink composition without the antimony being'presjent in an -amount sufliciently large to 'obscure the chromatic colour of the] ink composition.

The colouring material ink composition of the present invention may be embodiedin'sor used as printing or other'inks, or may be used to impregnate typewriter and other inked ribbons or may be incorporated in a transferable. composition usedinthe manufacture of carbon paper and other. transfer sheet material.

be copiedend this heat pattern-develops'the copy sheet byproducing the colouration in the thermo-sensitive composition thereof to produce'a copy of the original material. In general, the infra-red rays are directed on to the material to be copied'through the copy sheet, which is not itself absorbentof infra-red radiation.

' It has been found that, generally speaking, satisfactorycopiescan be obtained by such processes only from black writings, drawings or typings and black pencil writings and that it is'virtually impossible to operate a thermosensitive copying process'with coloured material. This method of copying is therefore not normally feasible with material which is partly in black and partly in a colour, e.g. red. Good copies can be obtained, however, from typed material produced by means of a black typewriter ribbon, which is impregnated with an which contains carbon black. Red typewriter ribbons and other coloured ribbons, such as purple, green and blue, are almost completely unsatisfactory from the'standpoint of obtaining copiesbyfmeans of ther fno-sensitive copying paper from material typed with them. Depending upon the colouring' material used, brown ribbons will sometimes produce matter which can be 'copiedin' this way, particularly if the brown colouring material in the typewriter ribbon ink is obtained by the addition 'of carbon black to another colouring matter, such as a red pigment.

In order to overcome this defectof coloured material, it has been proposed to add graphite'in a very high proportion in respect of the other coloured pigmentary matter used in the manufacture of typewriterribbon ink. German Gebrauchsmuster No, 1,734,641 refers to the use of a "small quantity of graphite for this 'purpose, butit has not been found possible to obtain any useful results unless large quantities are employed. This is the principal disadvantage of graphite for this purpose, since the high proportion necessary to incorporate sufficient black into the colouring material to enable writings produced with it to be absorbent of infra-red radiation renders the writings so dull in character as to be unsatisfactory for ordinary purposes.

It is therefore an object of the present invention to provide a coloured, i.e. non-black, colouring material which overcomes the defects of ordinary colouring materials in respect of thermo-sensitive copying processes and also avoids the disadvantages attendant upon graphitecontaining colouring materials. The expression chro- .It hasbeenfound that fairly large quantities of powdered or otherwise finely-divided antimony are generally required to give satisfactory results, but the colour of the other pigmentary or colouring matter used in the colouring. material. is not adversely affected and very good results can be obtained in producing written matter by printing, writing, typing or by using carbon paper. The actual quantity of antimony required to give the best results, as regards the quality of copies produced from the ,written matter ;by*means of a thermo-sensitive copy paper, depends to some extent upon'the colour and nature of the pigment or pigments, but in general it has been found satisfactory to employ the powdered antimony inan' amount of 15 to 25% by weight of the ink, the latter preferably containing 15 to 30% by weight of lake colour or other pigment or coloured material.

Commercial antimony can be readily powdered and can be'mixe'dand ground with the other ingredients of theink or other colouring material as if it were a pig- In entself it is carefully ground, such as on a triple roll mill, antimony can be obtained in an extremely finelydivided condition. 'If such an ink is used to impregnate a typewriter ribbon, the material produced by typing with the ribbon is found to be a better and much-brighter colour than that obtained with a graphite-containing ink ribbon. Y.

In order that the invention may be readily understood, the following specific examples are given.

Example 1 Parts by weight Lardoil 29 Light mineral oil 31.5 Triethanolamine oleate i p, b 2.4 Strong Violet Lake 20. Antimony 16.6

Example 2 Castor oil 41.7 Lard oil 10.4 Light mineral oil 14.0 Strong Red Lake 13.0 Dark Red Lake 3.5 Anti-oxidant 1 0.8 Antimony 16.6

1 Nonoxol D.C.P.

3 2 Example 3 Lard oil 26.5 Light mineral oil 29.5 Triethanolamine oleate 2.2 Strong Blue Lake 25.0 Antimony 16.7

Example 4 Light mineral oil 62.5 Strong Deep Green Lake 20.8 Antimony 16.7

The foregoing examples set out compositions suitable for use as inks, which can be used as such or used to impregnate typewriter or other ribbons. The following Example 5 sets out a formulation for the transferable coating of a carbon paper.

Example 5 Parts by weight The colour of the particular lake is chosen to suit the desired colour of the carbon paper dope, from the Strong Violet Lake, Strong Red Lake, Dark Red Lake, Strong Blue Lalze land Strong Deep Green Lake mentioned in Examples 1 o a ove.

We claim:

1. A coloured ink composition which is adapted to produce coloured written copy matter capable of being copied by a thermo-sensitive copying process, which ink composition consists essentially of an oil-containing vehicle, at least one chromatic-coloured colouring material in an amount of from 15% to 30% by weight of the ink composition and finely-divided antimony in an amount sufficient to give satisfactory thermosensitive copy by imparting infra-red absorptive properties to the ink composition without the antimony being present in an amount sufiiciently large to obscure the chromatic colour of the ink composition.

2. A violet-coloured ink composition according to claim 1, which consists in parts by weight of 29 parts of lard oil, 31.5 parts of light mineral oil, 2.4 parts of triethanolamine oleate, 20.5 parts of Strong Violet Lake and 16.6 parts of finely-divided antimony.

3. A red-coloured ink composition according to claim 1, which consists in parts by weight of 41.7 parts of castor oil, 10.4 parts of lard oil, 14.0 parts of light mineral oil, 13.0 parts of Strong Red Lake, 3.5 parts of Dark Red Lake, 0.8 part of antioxidant and 16.6 parts of finelydivided antimony.

4. A blue-coloured ink composition according to claim 1, which consists in parts by weight of 26.5 parts of lard oil, 29.5 parts of light mineral oil, 2.2 parts of triethanolamine oleate, 25.0 parts of Strong Blue Lake and 16.7 parts of finely-divided antimony.

5. A green-coloured ink composition according to claim 1, which consists in parts by weight of 62.5 parts of light mineral oil, 20.8 parts of Strong Deep Green Lake and 16.7 parts of finely-divided antimony.

6. A coloured transfer sheet material which is adapted to produce coloured written copy matter capable of being copied by a thermo-sensitive copying process, which consists of a paper web carrying a transferable coloured ink composition consisting essentially of an oil-containing vehicle, at least one chromatic-coloured colouring material in an amount of from 15% to 30% by weight of the ink composition and finely-divided antimony in an amount of from 15 %to 25% by weight of the ink composition, the antimony thereby being present in an amount sufi'icient to give satisfactory thermosensitive copy by imparting infra-red absorptive properties to the ink composition without obscuring the chromatic colour of the ink composition.

7. The coloured transfer sheet material of claim 6 in which the transferable coloured ink composition consists, in parts by weight of, 12.2 parts of fatty grey carnauba wax, 11.9 parts of ceresin wax and 30.7 parts of mineral oil as the oil-containing vehicle, 27.7 parts of a Strong Lake colour selected from the group consisting of Strong Violet Lake, Strong Red Lake, Dark Red Lake, Strong Blue Lake and Strong Deep Green Lake and 17.5 parts of finely-divided antimony.

8. A coloured inked ribbon adapted to produce coloured written copy matter capable of being copied by a thermosensitive copying process, which consists of a ribbon impregnated with a coloured ink composition consisting essentially of an oil-containing vehicle, at least one chromatic-coloured colouring material in an amount of from 15% to 30% by weight of the ink composition and finely-divided antimony in an amount of from 15% to 25% of the ink composition, the antimony thereby being present inan amount suflicient to give satisfactory thermosensitive copy by imparting infra-red absorptive properties to the ink composition without obscuring the chromatic colour of the ink composition.

References. Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Murmann: Zeitschrift-fiir Physik, vol. 54, March 1929 (pages 746-748).

Koller: General Electric Review, Infra-Red, March 1941 (pages 167-173).

Mitchell: The Analyst (1935), vol. (pages 454-61).

Claims

1. A COLOURED INK COMPOSITION WHICH IS ADAPTED TO PRODUCE COLOURED WRITTEN COPY MATTER CAPABLE OF BEING COPIED BY A THERMO-SENSITIVE COPYING PROCESS, WHICH INK COMPOSITION CONSISTS ESSENTIALLY OF AN OIL-CONTAINING VEHICLE, AT LEAST ONE CHROMATIC-COLOURED COLOURING MATERIAL IN AN AMOUNT OF FROM 15% TO 30% BY WEIGHT OF THE INK COMPOSITION AND FINELY-DIVIDED ANTIMONY IN AN AMOUNT SUFFICIENT TO GIVE SATISFACTORY THERMOSENSITIVE COPY BY IMPARTING INFRA-RED ABSORPTIVE PROPERTIES TO THE INK COMPOSITION WITHOUT THE ANTIMONY BEING PRESENT IN AN AMOUNT SUFFICIENTLY LARGE TO OBSCURE THE CHROMATIC COLOUR OF THE INK COMPOSITION.