US 2751276 A
Description (OCR text may contain errors)
June 19, 1956 w. c. EATON COLORED ADHESIVE TAPE Filed April 29, 1955 COLORED ADHESIVE TAPE Wentworth C. Eaton, Rochester, N. Y., assgnor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application April 29, 1953, Serial No. 351,849
4 Claims. (Cl. 8-18) This invention relates to a light-sealing adhesive tape. More particularly this invention concerns an improved light-sealing adhesive tape which is particularly adapted for uses in the photographic industry.
In the art there are many instances where there is a need for an adhesive tape having the property of being capable of not only joining parts together but to form a relatively light-tight joint. This need is encountered frequently in the photographic industry. That is, for example, in sealing packages containing light-sensitive photo` graphic materials it is, of course, important that the seal be sufficiently light-tight that any light leakage be well below that which would cause fogging of the photographic materials. It will also be noted that the accomplishment of such light-tight seals should be with materials which would not chemically or otherwise exert an injurious effect on the sensitive photographic contents.
It has been customary in the prior art to prepare such type tape by rather heavily impregnating or loading the tape with dark colored pigments. For example, the use of rather substantial quantities of graphite in the production of such type tape has been resorted to. While the resultant prior art tape has merit from the standpoint of giving a relatively light-proof sealing, there have been cer tain disadvantages in such prior art tape. For example, tape containing or associated with a high content of a dark pigment may be of such an overall dark color that it presents an unpleasing appearance. Furthermore, because of the dark color of such tape it is either impossible to place readily visible markings upon the tape, or if an attempt is made to mark it, here again relatively unsatisfactory results have been obtained.
It is therefore apparent that providing an improved light-proof tape which is of pleasing appearance and which is receptive to clear visible marking, represents a highly desirable result. After extensive investigation I have found how such improved tape may be prepared in an economical manner, lending itself to large scale manufacture.
This invention has for one object to provide an improved relatively light-impermeable adhesive tape. A special object is to provide a light-impermeable tape of the class mentioned, which is especially adapted for uses in the photographic industry. A still further object is to provide a relatively light-impermeable tape which is especially adapted for sealing seams of various types of containers where -it is desired to prevent the penetration of light to the interior of said containers. Another object is to provide a tape of the class indicated which is not only more pleasing in appearance, but which may be printed upon or otherwise marked with the result that said markings are more clearly and readily observable. Still another object is to provide a method for the manufacture of the improved tape referred to herein. Other objects will appear hereinafter.
In the broader aspects of my invention I have found that a light-colored fabric base may be first coated with a light-colored adhesive. The light-colored adhesive is then damage thereto.
2,751,276 Patented June 19, 1956 overcoated with a dark, such as a black, adhesive coating composition. By this combination the light-sealing qualities of the adhesive tape appear to be maintained. However, the fabric side of the tape, namely the side away from the dark-colored adhesive, still maintains its light color, hence more readily Visible and pleasing appearance.
' industry, the fabric tape is of a light color, colored by certain coloring materials which are noninjurious photographically. The light-colored fabric foundation is then coated with a white adhesive of a special composition which will be described in detail hereinafter. This white adhesive is then overcoated with a black adhesive composition of a special formulation as will also be described in detail hereinafter.
The foregoing describes the generic aspects of my invention. However, if desired, the printed fabric portion may be overcoated with a lacquer glaze or other type of textile nish. Also as desired, the adhesive surface of my tape may be overcoated with a thin protective tissue media or coating for temporarily covering the adhesive prior to use. Such coatings may be detachable to expose the adhesive or may be of such minute thinness that upon the application of pressure they merge into the adhesive permitting the adhesive to function. However my tape as generically described is sutliciently stable that the adhesive side may be rolled up against the fabric side without In other words, my adhesive combination is of such a character that the dark coloring therein does not migrate into the fabric either when in direct contact therewith or by migrating through the intermediate light-colored adhesive layer.
As respects the fabric base material, while various commercially obtainable cloths may be employed, I have found that a material described as thin lawn cloth is quite satisfactory. This material is of an approximate construction of 96 x 100 ends and picks per inch and a weight of 7 yards per pound.
For a further understanding of the instant invention reference will be made to the attached drawing. Fig. l is a diagrammatic side elevation view of apparatus arrangements such as might be used in manufacturing light-impermeable tapes in accordance with the present invention.
Fig. 2 is a diagrammatic representation on an exaggerated scale of a cross section of the tape of the present invention.
Refering tor Fig. l (A), 2 represents a roll of the fabric which is to be converted into the fabric tape of the present invention. For example, this roll might be comprised of the lawn cloth referred to above. The fabric is unrolled and guided through the equipment by virtue of drive or guide rolls such as 3. The mangles 4, and pick-up roll 5 may be employed to motivate the fabric base through the equipment. In the passage of the fabric through the process it passes through dye or coloring tanks 6 and 7 where it is colored, then through mangles 4 to squeeze out surplus liquid, then over dryer drums 3 where remaining liquid is removed and finally wound up on 5.
Referring further to Fig. 1 and now to (B), the colored cloth on 5 is transferred to roll 12. The raw fabric passes by means of suction drive 13, consisting of a series of small driven rolls forming the top of a suction box which hold the material tightly against the rolls and the driven rolls pull the material away from the stock roll, in the vicinity of a hopper 16 or other equivalent device for applying the first adhesive layer, namely the layer of the light-colored adhesive. The preliminarily coated fabric then passes through suitable drying or solvent removing device 17. In this device the adhesive is caused to set up to some extent. However complete curing of the adhesive at this state is not necessary. Upon emerging from the dryer the preliminarily coated fabric passes in the vicinity of a second coating device 18, from which is applied the layer of dark-colored adhesive. Suitable smoothing means such as doctor blades, leveling knives or the like (not shown) of course can be included in the equipment for controlling the accuracy of the coating. Likewise in place of coating hoppers, coating rolls or the like may be used.
After the coating from device 18 is applied, the'fabric tape then passes into a second dryer 19 where suicient curing takes place to remove a'substantial portion of the solvent or other similar volatiles from the adhesive to form the finished tape. l
Other operations, such as preliminary slitting and the like, may be accomplished by suitable equipment, generally indicated at 20. The finished tape is wound up on rolls 23 and 24.
Referring now to Fig. 1 (C), the rolls from Z3 or 24 are mounted at 25 and fed through a printer 26 from which it then passes to any further treatment, such as overcoating with a lacquer, further slitting, etc.
Referring to Fig. 2, it will be observed that my tape is made up of the fabric or foundation layer 31, such as a layer of lawn cloth referred to above. This cloth in accordance with my preferred embodiment may be colored with certain dyes which do not exhibit an adverse photographic effect. A description of certain of these dyes will be set forth hereinafter. 32 represents the layer of light-colored adhesive. 33 represents the layer of dark-colored adhesive. The entire combination gives an excellent flexible, light-impermeable tape which has a pleasing appearance and is readily receptive to marking or printing with conventional inks and marking devices.
A more complete understanding of my invention, and t particularly the preferred embodiment thereof, will be had from a consideration of the following specific examples. It is to be understood that these specific examples concern a light-impermeable tape very suitable for use in the photographic industry. However, it is to be further understood that my tape has other uses and that the following speciiic examples are primarily for the purpose of illustration.
Example I ln accordance with this example, the fabric used was a light lawn cloth as above mentioned. Its approximate construction was about 100 ends and picks per inch and the weight was 7 yards per pound. The fabric was coated in an apparatus as shown in Fig. l. That is, the first coating applied from hopper 16 comprising white adhesive of the following composition:
Antioxidant r4 A portion of the benzene solvent was evaporated from the tirst coating. Then the black adhesive from hopper 18 was applied over the first-mentioned adhesive. This adhesive was of the following composition:
Natural rubber 7.50 Rosin 7.00 Lanolin 1.50 Graphite 1.00 Barytes 5.00 Benzene 77.50 Antioxidant .50
Example II In accordance with this Example a tape especially useful for photographic purposes was prepared. In this example the fabric used was of the same general weight and construction as the fabric of Example I. However, in this Example the fabric was colored with a yellow dye in 6 and 7. The dye used was Pontamine Yellow SXPE. This is a dye of the following general composition:
SOaNa Naoah dosNa The yellow dye is the sodium salt of dinitro azo distilbene tetra sulfonic acid, Inex No. 622.
It has been found that fabric thus colored does not exert an adverse photographic effect. In place of the dye just mentioned, it is possible to use Amanil Chrysophenine G. This latter dye has the following general composition:
NaOsS This is para-ethoxydiazobenzene stilbene disulphonate- Index No. 365, Schultz Index No. 726.
The yellow'fabric just described was then overcoated first with a white adhesive generally in accordance with the white adhesive used in Example I. The first adhesive coated was then further overcoated with the black adhesive of Example I. The finished tape was cured and wound up. This particular yellow tape was printed in red type with excellent results. in addition, the lightimpermeability of this type was most excellent. This may be due to some extent to the black and yellow dye combination of the tape as well as to the fact that the intervening white layer also exhibits some deterrence to light passage.
tially-the same as that described under Example Il, is used. However, the white adhesive used in this example is termed mixed white, and has the following composition: (approximate percentages by weight) GRS-80 synethetic rubber 8.00 Piccolyte resin 6.00 Titanium oxide 4.00 Barytes 2.00 Lanolin 1.50 Benzene 78.00 Antioxidant .50
The tape was overcoated with a black adhesive as already described in the other examples. Likewise, in this Example the finished tape exhibited an excellent appearance as well as good light-impermeability and capability of sealing package joints.
While the foregoing examples are illustrative of my preferred embodiments, certain changes may be made in my invention. For example, it is possible to incorporate suitable yellow coloring in the white adhesive composition, particularly where this light-colored composition is to be applied to a yellow facbric. However, the white adhesive does brighten the yellow fabric to some extent. Also, in the manufacture of tape for uses such as the sealing of food containers against light peneration or other uses where the problems of a photographic damage and the like may not be present, it may be possible to uitilize different adhesive compositions than those set forth above. That is, in some instances a carbon black-containing black adhesive may be employed. However, the graphite-containing adhesive specified above is regarded as much superior. Likewise, in place of the natural rubber in some instances it may be possible to use synthetic rubber or mixtures of natural and snythetic rubber.
The proportions may be varied several percent each way from the value given. That is, considering the rubber content of 8%, for example, this may vary from 4% to The solvent may vary from 60-80%, the pigment from 5% to 20%. In still further detail, the amount of rosin may vary between 3 to 12%, lanolin .5 to 3%, zinc oxide 2 to 6%, barytes 1 to 10%, antioxidant .25 to 2%, and graphite ylo to 4%.
In place of the pigments and certain other ingredients given in the preferred embodiment, the following may be used. Various mixtures of TiOz and BaSO4 and a lead salt from the group consisting of PbCrO4 and PbCr2O:. Other resins such as Piccolyte,1 Staybelite,2 and coumarine indene resins.
As antioxidant I may use aldol alpha-naphthylamine, phenyl beta-naphthylamine, or p-(p-to1ylsulfonylamido)- dipheulamine.
As indicated above, the tapes in accordance with the 1 Terpene resin.
2 Hydrogenated rosin.
195(lmdbook of Material Trade Names, Zimmerman & Lavine,
present invention may be used for any of the various uses for which similar tapes have been utilized. In addition they are especially valuable for use where it is desired to print or mark upon the tape in some manner.
l. A tape consisting essentially of light colored cloth, one surface only being coated with pigmented light colored adhesive, said light colored adhesive being further coated with a black pressure-sensitive adhesive pigmented with graphite, said tape being light impermeable and capable of taking printing ink on the nonadhesive coated side.
2. A tape consisting essentially of a light colored lawn cloth, one surface only being coated with a pigmented light colored adhesive, said light colored adhesive having the following composition (percentages by weight), natural rubber 4--l6, rosin 3-12, lanolin .543, zinc oxide 246, barytes l-5, benzene -80, antioxidant .25-2, said light colored adhesive being further coated with a black pressure-sensitive adhesive, said black adhesive having the following composition: (percentages by weight) natural rubber 4-16, rosin 3-12, lanolin .5-3, graphite .5-4, barytes 3-10, solvent 60-80, antioxidant .252, whereby a light impermeable adhesive tape is obtained which has a pleasing appearance and is capable of receiving ordinary ink printing on the light colored cloth surface thereof.
3. A tape consisting essentially of light colored cloth, one surface only being coated with pigmented llight colored adhesive, said pigment being from the group consisting of PbCrO4 and PbCrzOv, said light colored adhesive being further coated with a black pressure-sensitive adhesive pigmented with graphite, said black adhesive also containing rubber, rosin, and barytes, said tape being light impermeable and capable of taking printing ink on the nonadhesive coated side.
4. A tape consisting essentially of light colored cloth which cloth is colored with a yellow dye from the group consisting of Pontarnine Yellow SXPE and Amanil Chrysophenine G, one surface only of the cloth being coated with a pigmented light colored adhesive, said light colored adhesive containing natural rubber', rosin, lanolin, zinc oxide and barytes, said light colored adhesive being further coated with a black pressure-sensitive adhesive pigmented with graphite, said black adhesive in addition to the graphite also containing natural rubber, rosin, lanolin, barytes, said tape being light impermeable and capable of taking printing ink on the nonadhesive side.
References Cited in the le of this patent UNITED STATES PATENTS 2,236,567 Drew Apr. 1, 1941 2,352,463 Wenzelberger .Tune 27, 1944 2,355,632 Coffey Aug. 15, 1944 2,555,745 Hopkins June 5, 1951