DE2044780A1 - - Google Patents

Description

September 8, 197ο Gzy / Ha.

SGHOELLER TECHNICAL PAPERS, INC., Pulaski, New York / U.S.A.

Paper for photographic purposes and processes for its

Manufacturing

The invention relates to a gray, opaque, made of fibrous paper for photographic purposes, in particular Can be used in diffusion photography. She concerns also a method for producing such a paper.

It is known to use light absorbing dyes such as water-dispersible black pigments or water-soluble ones Add black dyes to paper to make opaque papers. The black papers so produced are for some purposes are unsuitable, especially when they have to be coated with a coating of white pigments in order to achieve a to maintain white surface · To achieve a complete Opacity also required the addition of very large amounts of light absorbing dyes.

In photographic processes in which the image is created by touching the negative with the positive print paper outside the camera, it is important that the negative and positive be opaque to actinic light. To the generation a clear and distinct picture, it is also necessary that the paper must be white for the positive

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printing surface.

So far the paper for the positives has been made by applying a photographic emulsion to white paper. Diss38 paper had one or two white-pigmented coatings, Q13 in gelatine gelatine and barite contained the opacity of such a paper for actinic light was characterized erhalt5.T. _5, characterized in that the rear side with a coating agent ^as übersc.gf Ä iK. an organic solvent sin. black light absorbing material contained _e In some cases became s £ t2lion sin white pigmented *> V c3? z'ig applied over the black Ov sr .3Ug on the jerk site.

! The production of this "Dekanaten paper = for aie positive was .s-clr-visrigj. Seil several achvvare coating a;: ig avenge be muli: t ■:.: · ;. _s Since the G-ewicr.t eier Üteraügs i: L ratio to weight c.ö-5 P-. · pi ar ss high "7ar. _: had the same papisra one low

P- ^ s yrZ irid-uiigsgeitiäSe Papiar iat marked thereby, da. '; te in 4-l.gif.3igerpre-division 9in Titariptgsent, a Li ./:-3 , hiwX'3i3renden dye and colloidal milk € n. old one elö ^ tr: i.3cheri charge contains , i.lle this Be a ir and share kcim-ar 0-or PHlρ3 of the paper forming I ^! a3c: "Jtoffas in the form of waür- _: -go ^: :: i dispersions or solutions are z'aszzzt- ,

liae örfilnciangsga according to? Papiar can be one on one side White pigmented over-eye can be on disaes coating Eins d-irohlässiga emulsion be applied, on the gegenü-börlisganden Side, the paper can have a rough, pigmented, have a coating that is resistant to water and solvents,

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2Ü44780

The paper according to the invention is practically opaque, even if the amount of the light-absorbing dyes is only 1.3 grams., per square meter of paper. The reason for this may be cannot be explained. It is possible that the light scattering pigment particles by refraction and reflection at d c -, '»flatten with air a longer way for the light through the paper and therefore have more opportunities for the light to absorb from the dyes will. Furthermore, the electrically charged ones also wear colloidal particles may help to increase the light-scattering effect of the titanium pigments.

The paper according to the invention has the advantage that it is gray, and that it is therefore not necessary Überitlge especially on the back to apply the required opcs ^ tfit au achieve. The gray appearance diminishes also the amount ^ r white pigmented coatings that necessary to give the paper a white surface. The number and thickness of these coatings can therefore be reduced will. A positive release paper of higher strength is obtained because of the quantitative proportion of colored fibers is higher.

A paper is considered to be opaque if it does not let in enough light to get a very good result within a certain period of time Visibly desensitize sensitive negative emulsion upon exposure to light. The test for opacity is carried out so that the emulsion side of a sensitive negative, e.g. Polaroid 3ooo Speed Negative, with the paper to be tested is covered. From a distance of 23 cm, use the light of a 375 watt lamp for one minute

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BATH ORIGINAL

"exposed" The negative exposed in this way is then used until it is developed and fixing according to the usual procedures in the dark The paper to be tested is considered completely opaque if the negative is not visibly blackened and black spots are absent.

As according to the invention can light-absorbing dyes used in water-dispersible black pigments or water-soluble black dyes ^ "A preferred dye is colloidal carbon black ₀ Commercially such carbon black is in the form of a colloidal dispersion 38 ^ strength is available, the ZOB ₀ sold by the Columbia Carbon Company under the trade name "Aquablak ⁿ B ⁿ . This carbon black is designated in the Color Index of 1956 as C ₀ I ₀ Pigment Black 7 (C ₀ L 77266). The carbon black can be wholly or partly water-soluble black dye ©. A preferred dye 1st Nigrosin WSB ₀ In the Color Index of 1956 this dye is designated as C ₀ I ₀ Acid Black 2 (C ₀ I ₀ 5o42o) «,

Usable titanium pigments according to the invention are titanium dioxide W in rutile and anastase form, furthermore potassium titanate, mixtures of titanium dioxide and potassium titanate are particularly valuable. The titanium dioxide is one that is usually used as a filler for paper ₀ It usually has an average diameter of about 35o Millimicrons. Potassium titanate is fibrous. A method for producing such a fibrous titanate.1st described in US _{Pat. No. 0} 3 328 117 “Particularly suitable fibrous potassium titanate has fibers about 10 microns in length and about 2oo millimicrons in diameter. One such pigment is from

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2Ü4478Q

the E.I. du Pont de Nemours & Company, Wilmington, Delaware, under the trade name PKQ? pigmentary potassium titanate.

At least 1o fo of the titanium pigment can be replaced by known inexpensive fillers, such as sodium silicoaluminate, without the properties of the paper according to the invention being noticeably changed as a result.

To produce the paper according to the invention, the " Pulp of the fibrous materials at least H grams of titanium pigment and at least 1.3 grams of the light absorbing. Add dye per square meter of paper. The table below I shows the preferred and sufficient amounts of these Substances per square meter of paper, these quantities being independent of the weight or thickness of the paper. at the determination of these values were papers with a thickness used from 0.15 to 0.23 millimeters.

Table I.

'- ■' Jf. '.. ■■■'

more preferred usable

Titanium pigment

Light absorbing dye 2.5 g 1.3-3.8 g

As an electrically charged colloidal material becomes water-containing Magnesium silicate preferred. This consists of rod-shaped particles with an average diameter of about 20 millimicrons. The particles are electrically negative charged. A method of making one colloidal magnesium silicate is described in the United States patent No. 3 458 393. It is distributed by the

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20447

FMG Corporations, Philadelphia, Pennsylvania, under the tradename Avibest C, another electrified colloidal material that can be used in the present invention is hydrous alumina. This material has an average particle diameter of about 30 millimicrons and is electrically positively charged. It is obtained by the hydrolysis of aluminum chloride in a flame, whereby aluminum oxide crystals are formed. About 90% of these crystals are in the form of gamma. This material is sold by the Cabot Corporation Boston, Massachusetts under the trademark ^: snam®n Alon C ₀ These is trically charged colloidal particles are added in amounts from $ 1.5 to $ 15 based on the weight of the titanium pigment to obtain an opaque paper of the properties given above, as shown in Table I.

Example I.

A 2 ^ aqueous dispersion of hydrous magnesium silicate (Avibest) and an aqueous 50% dispersion of titanium dioxide in rutile form ₉ which held 1% sodium silicoaluminate were prepared separately, one with a high speed running mixer was used. The dispersion of the titanium dioxide contained, in addition o, 3 $> Sodium "hexamstaphosphatj based on the weight of the titanium dioxide to the dispersion of the pigment particles to © rleichtern" DI® two dispersions a 3 ^ strength slurry of Sulfitkraftzellatoff were added in is specified above. This pulp had previously been refined to a Canadian liberty of about 35o. Ea were ©, 5 Ί "magnesium silicate and 1o%> of fill off pigment β added, based on the weight of the fibers" Before Herateilung

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ORiGINAL JWSPECTED

20447

opaque paper on a Fourdrinier machine was added 2 fo cationic starch and about 1 $ to resin, both based on the content of fibers. By the addition of alum was the pH adjusted to about 4 ₉ 5 ₀ "was then added 1.5 $ Predispersed carbon black, based on the amount of fibers, immediately after the addition of the cationic starch. A paper containing no knots and holes was then produced by conventional methods. The paper was pressed and dried in the conventional manner. The finished paper was glued with 6 io oxidized starch. This was followed by calendering with a machine in order to obtain a smooth surface for the other coatings.

The gray paper obtained had a thickness of O, 19 mm., A weight vcm 17o grams per square meter and contained .je square 15 ₉ 5 grams of the fillers and 2.1 grams of carbon black. The fillers and other additives were practically completely retained by the paper because the white water was kept in circulation. The paper obtained had a uniform gray color and was completely opaque according to the test methods described above «,

Examples II and III

After following Example I, more gray papers became made that looked similar. Deviating from the example I the dispersions of magnesium silicate and titanium dioxide were mixed before adding them to the fiber suspension admitted. Further differences emerge from Table II.

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ORIGINAL BATHROOM

Table il

Example II Example III Thickness, millimeters o, 18 mm o, 19 mm Weight g / m 166 165 Fillers g / m ² 18.4 19.0 Carbon black g / m ² 2.36 2.5 held fill
amount of substance fo, calculated
as ashes 94 93 Opacity of the paper Great Completely

Example IV

The 0.19 mm thick gray paper made according to Example I. was, was coated on one side in an amount of 50 g / m with an aqueous coating of 62 parts Titanium dioxide, 38 parts of barium sulfate, 1o, 8 parts of gelatin and Contained 6 parts of glycerine. The obtained sheet was completely opaque and coated on top. Page completely white without the gray color of the paper.

Example Y

A gray paper according to Example II was coated in two stages in an amount of 45 g / m with an aqueous mixture, 100 parts of titanium dioxide, 12 parts of gelatin and 6 parts Contained glycerine. The paper coated in this way was calendered again. Brought to the opposite side of the paper a latex coating is applied in an amount of 18 g / m, which contains 55 parts of polyvinylidene chloride, 5 parts of titanium dioxide and 0.19 Contained parts of soot.

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Example VI

A gray paper according to Example I was coated according to Example "V, with the exception that the back coating was a Thickness of 0.025 millimeters and of unpigmented High density polyethylene was made, which was applied by extrusion became.

Usual gelatin positive emulsions were applied to the papers applied according to Example V and Example VI. The positive papers thus obtained could be used successfully in combination with an opaque negative, developing outside the chamber, i.e. in the presence of; · actinic light, took place. In any case, the photographic prints were satisfactory and had no stains or defects from light penetration. .

Example VII . _: . , ·

Following the procedure of Example I, a gray paper 0.2 mm thick was produced. In this the magnesium silicate was replaced by 0.5 % hydrous aluminum oxide (alum C). It contained $ 13.5> fillers based on the weight of the fibers. The paper weighed 166 grams per square meter and contained 19.5 grams of filler and 2.3 grams of carbon black per square meter. The fillers were retained in an amount of 93 # as determined from the determination of the ash. The paper produced in this way was uniformly gray and completely opaque.

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- 1 © -

Example VIII

laugh, the procedure of Example I made a 0.2 m thick. made of gray paper "Bi © - fillers" consisted of 7 ° / o titanium dioxide and 7 $ Kslituatitaaat ,. based on the amount of fiber ₀ The paper had a QimöratmetergewiGhf of 154 grams, "It contained two © Sramm titanium pigments and 2 per square meter, 2 grams of HuS ₀ The filler was retained in an amount of $ 93. The resulting gray paper έβ, τ completely opaque.

When comparing the opacities worn papers, iron which one® was made according to Example I and three others were made generally in the same manner but (A) the hydrous® magnesium silicate was omitted,., Or (B) the titanium pigm® at omitted wr _s © egg (G) the Rui was omitted j @ r'ga "b

Paper Ä (lcsdn water-containing lagium silicate) paper B (no sitan pigment) Paper C (no cover)

clear kegatiT, no black Meeken

vi'ele 'black hedges many black HeeXen ·. negative turned dark.

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Claims (17)

20U78Q Patent claims: Gray, opaque paper for photographic purposes consisting of fibrous materials, characterized in that it contains a titanium pigment, a light-absorbing dye and in an amount of about 1.5 to 15 percent by weight, based on the weight of the titanium pigment, colloidal particles an elsewhere • charge contains » 2. Paper according to claim 1, characterized in that it contains about 1.3 to 3.8 grams of the light-absorbing dye per square meter. 3. Paper according to spoke 1 or 2, characterized in that % Q contains , as a light-absorbing dye, black pigaente dispersible in water, black dyes soluble in water, or a seaiseh of both. 4. Paper after. Addressed 3, characterized in that it is as water-dispersible pigment contains colloidal carbon black. 5. Paper according to spoke 3 or 4-, characterized in that it contains ÜTigrosin WSB as a water-soluble dye. 6i. Paper according to one of Claims 1 to 5, characterized in that there is about 14 to 26 grams of des per square meter Contains titanium pigments. 7. Paper according to one of claims 1 to 6, characterized in that that it contains titanium dioxide and / or fibrous potassium titanate as titanium pigment. 1771526 BATH 2 ü U 4 7 8 Q 8. Paper according to one of claims 1 to 7, characterized in that that up to 1o ^ of the Titanplgments are replaced by an equivalent amount of a filler. 9. Paper according to one of claims 1 to 8, characterized in that it is as colloidal particles, with an electrical Charging particles of hydrous magnesium silicate about 20 millimicrons in diameter P - and a negative electrical charge. 10. Paper according to one of claims 1 to 8, characterized in that that it is as colloidal particles with an electrical charge particles of hydrous aluminum oxide with a diameter of about 30 millimicrons and contains a positive electrical charge » 11. Paper according to one of claims 1 to 1o, characterized in that that it has a white pigmented coating on one side. ik 12. Paper according to claim 11, characterized in that it on the opposite side of the white pigmented coating, a rough, pigmented coating that is resistant to water and solvents has a permanent coating. 13. Paper according to claim 12, characterized in that the coarse pigmented coating consists essentially of polyethylene and has a thickness of about 0.025 mm. 14. A method for producing paper according to any one of claims 1 to 1o, characterized in that one 109817/1526 bath aqueous pulp of the fibers forming the paper an aqueous one Slurry of the colloidal particles with an electrical charge and an aqueous slurry of the titanium pigment, then adding an aqueous slurry of the light absorbing dye by adding Alum adjusts to an acidic pH, and the suspension thus obtained in a conventional manner on paper processed and this dries. 15. The method according to claim 14, characterized in that the aqueous slurries of the colloidal particles with an electrical charge and the titanium pigment prior to adding to the pulp. ν 16. The method according to claim H or 15 for the production of paper according to claim 11, characterized in that one after processing into paper on one side white pigmented coating. 17. The method according to claim 16 for the production of paper according to claim 12 or 13 ,. characterized in that after applying the white pigmented coating on the opposite side a rough, pigmented _. ^ _ett ^ .... g _ö g _eH fag _3ΘΓ and Msmittel · bea-to-coating brings up. , 10 98 d? / 15 26