US3884692A

US3884692A - Photographic support

Info

Publication number: US3884692A
Application number: US340790A
Authority: US
Inventors: Nobuhiko Minagawa
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1972-03-14
Filing date: 1973-03-13
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20
Also published as: FR2176044B1; DE2312674A1; GB1415464A; FR2176044A1; DE2312674C2; JPS4894417A; JPS5218020B2

Abstract

On the back of a polyolefin laminated paper, a support for photographic light sensitive material, a coating layer composed of colloidal alumina is applied in order to prevent the paper from blistering during microwave heating.

Description

O United States Patent 1 [111 3,884,692 Minagawa May 20, 1975 [54] PHOTOGRAPHIC SUPPORT 3.l69,865 2/1965 Wood 96/85 3,352 682 11/1967 Harris et a1. 5 96/95 [75] Inventor: Nobuhrko Mlnagawa, Shrzuoka, 3,520,242 7/1970 Kemp et 96/85 Japan 3,525,621 8/1970 Miller 96/85 3,743,537 7/1973 Honjo et a1. 96/85 [73] Assgnee' 5" i' 3,769.020 10/1973 Verburg." 96/85 anagawa 3,793,029 2/1974 Parker 96/85 [22] Filed: Mar. 13, 1973 2 1 App] 340 790 Primary ExaminerMary F. Kelley Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [30] Foreign Application Priority Data Mar. 14, 1972 Japan 47-2588] [57] ABSTRACT U-S. CL R o th ba k of a polyolefin laminated paper, a sup- [51] hit. Cl G036 l/86 port for photographic light Sensitive material, a coat [58] Fleld of Search 96/85, 87 ing layer composed f colloidal alumina is applied in order to prevent the paper from blistering during mi- [56] References Cited crowave heating UNITED STATES PATENTS 7 7 2,647,835 8/1953 Weaver 96/85 14 Clams 2 Dmwmg 1 PHOTOG RAPl-IIC SUPPORT BACKGROUND OF Tl-IE'INVENTION l. Field of the Invention v The present invention relates to an improved'support for photographic papers.

2. Description of the Prior Art It has been a recent tendency the photographic lightsensitive material art to promote development processing. As a part of this trend, water-proof photographic paper has been developed and put into use. With a water-proof photographic paper comprising a paper support coated on both sides with a hydrophobic polyolefin resin the time required for washing and drying after development processing has been greatly shortened because the support does not absorb development processing solution. Such papers have, however, required the employment of a different method of drying as compared to conventional papers.

Heretofore, the drying of photographic papers subjected to development processing has usually been conducted by bringing the emulsion-coated surface of a non-dried photographic paper into contact with a heated, smooth metallic plate to thereby evaporate from the back of the photographic paper moisture contained in both the emulsion layer and the support paper, i.e., by so-calledferrotype drying.

However, in a water-proof photographic paper ferrotype drying cannot necessarily be said to be the optimal drying method because'the support does not have permeability to water vapor. Rather, there is a tendency to use drying methods based on hot air, infrared rays or the like. One drying method of extremely high efficiency, microwave heating, has recently been considered by the art. In microwave heating, the time'required for the temperature to rise due to thermal conduction is so small as to be negligible because microwave heating causes internal heat generation in the substance heated. In addition, microwave energy'is absorbed most efficiently by water molecules. Therefore, microwave heating can be said to be extremely advantageous as a method for drying photographic papers.

Where drying with microwaves is applied to a waterproof photographic paper, water contained in the emulsion layer absorbs microwave energy to generate heat which contributes to the drying of the emulsion layer, while water originally contained in a slight amount in the paper constituting the support similarly functions as a heat-producing body and promotes the drying of the emulsion layer. For these reasons, the microwave drying of water-proof photographic paper will probably be rapidly put into use in the near'future.

SUMMARY OF THE INVENTION The inventors have discovered, however, that the microwave drying of water-proof papers has two serious pletely dried with microwaves, water-,drops remain undried on the back of the support.

2. In microwave drying blisters are liable to occur on the'polyolefin film coated on the back of water-proof photographic papers. .k

The inventors will not herein venture to discuss in detail the cause of such blisters, but, roughly speaking, the cause is consideredto be as follows; water contained in a paper support is vaporized by the microwave heating, resulting in an increase in-the pressure inside the support, which leads to the deformation of the polyolefin laminated on the back of the support, the polyolefin being in a softened state.

Water drops described in item (1) above hinder the effeciency of the heating process, which is the strongest merit of microwave heating,'and the blisters described in item (2) above spoil the appearance of the photographic paper to such an extent that the commercial value of the photographic papers is completely lost. Therefore, in putting microwave drying of water-proof photographic papers into use, it is necessary to remove the above-described two defects. v

As a result of extensive investigations to solve these problems, the inventors reached the present invention, i.e., the above defects are overcome with a photographic support comprising a polyolefin-laminated paper having on its back a coating layer of colloidal alumina.

BRIEF DESCRIPTION OF THE DRAWINGS DETAILED DESCRIPTION OF THBiNyENTi There is no particularrestriction onthe kind and thickness of the paper used in the invention; but paper for photographic uses, art paper,etc. having smooth surfaces and weighing g/m to 300 g/m is preferred. I

The polyolefins used in this invention are polyethylene, polypropylene and mixtures thereof in any proportion.

The polyethylene and polypropylene used may beslected from any of those in' the prior art, and their equivalents, which have been used to form polyolefin laminated papers, and the improved results of the present invention are achieved with all of such materials. Preferably the polyethylene has a melt index of about 1 to about 30 and a density of about 0.91 to about 0.97, while the polypropylene has a melt index of about 0.1 to about 20 and a density of about 0.88 to about 0.91. These ranges are not limitative, however, and are merely to serve as a guideline to one skilled in the art.

The polyolefin can be used in various thicknesses, but at thicknesses much less than .1 [J. insufficient water-proofing may be achieved, while no need exists to use a thickness much greater than 100 u.

Polyolefin-laminated papers are usually prepared by casting molten polyolefin onto arunning paper base, i.e., by the socalled extrusion coating method, whereby both sides of the paper are laminated or coated with polyolefin. The surface of the polyolefin-laminated paper to which an emulsion will be applied can be a glossy surface, matted surface, silk-like surface, etc. depending upon the use thereof, whereas the back of the laminated paper is usually non-glossy.

The colloidal alumina used in the invention is fibrous alumina (hydrate) l mu to 1,000 mu, preferably 10 my. to 100 mu, in size. Processes for producing the same and the properties thereof are explained in detail in Japanese Pat. Nos. 20150/64, 14292/65 and 570/66.

A process for providing a coating layer of colloidal alumina on the back of a photographic support comprising a polyolefin-coated paper is specifically described below.

Colloidal alumina is diluted with water or an organic solvent miscible with water to prepare a coating solution. The concentration of colloidal alumina in the coating solution is set taking into consideration the coating amount required, the viscosity of the solution suitable for the coating method employed and the like. However, usually, the concentration of solid ingredients, i.e., alumina, is in the range of from 1 g to 50 g per 1 liter of the coating solution. In addition, it does not destroy the benefits of the present invention to add various resins, dyes, matting agents such as silica, inorganic substances, and the like to the colloidal alumina coating solution in order to improve other characteristics such as the coefficient of friction, writing property and color. For instance, the additive resins can be water or organic solvent soluble resins such as polyvinyl acetate, polyvinyl alcohol, gelatin, nitrocellulose, etc., the dyes can be any dye which is not decomposed at process conditions, the matting agents can be selected from those commonly used in the art, e.g., clay, silica, etc. and appropriate inorganic substances are water soluble compounds such as sodium chloride, sodium sulfate, potassium nitrate, etc.

The thus obtained coating solution containing colloidal alumina is applied to the back of a polyolefinlaminated paper by any usual coating method such as roll coating, bar coating, gravure coating, etc.

It is sufficient to apply the colloidal alumina in an amount of not more than 1 g per 1 m of a support (exclusive of other components), generally in an amount greater than 0.05 g/m Amounts greater than 1 g/m can .be used, if desired, but no significant increase in improved results is obtained. The 0.05 g/m is a more important parameter as the upper figure is nonlimiting.

Activation of the polyolefin surface prior to the coating of the colloidal alumina is not particularly required, but, where resin is contained in the coating solution or where especially strong adhesion between the coating layer and the polyolefin surface is required, it is preferred to activate the polyolefinlaminated surface by corona discharge or the like, e.g., corona discharge as described in British Pat. Specification Nos. 771,234; 715,914; 870,224; 989,377; 971,058; 1,005,631; 1,019,664; 1,043,703; 1,134,211 and 1,136,902; U.S. Pat. Nos. 3,411,908; 3,53,922; 3,549,406; 3,520,242; and 3,076,720; mechanical roughening as described in British Pat. Specification No. 1,076,410; flame treatment as described in U.S. Pat. Nos. 3,072,483; 3,153,683; 3,255,034; 3,375,126; 3,431,135; 3,590,107, etc. and in British Pat. Specification No. 1,010,649; elution as described in U.S. Pat. No. 2,846,727; ozone treatment as described in U.S. Pat. No. 2,715,075; radio frequency electromagnetic treatment as described in British Pat. Specification No. l,294,l 16; andchromic acid treatment as described in Japanese Pat. No. 38-22148.

The characteristics required of the thus obtained backcoating layer are: it should not be delaminated during the production or use of the photographic lightsensitive material; it should exert no harmful influence on a photographic emulsion; it should not cause sticking or adhesion to the surface emulsion layer under high humidity conditions; and it should prevent the formation of above-described'water drops and blisters. The colloidal alumina coating layer in accordance with the invention satisfies all of the above-described requirements.

Furthermore, in addition to the intended microwave drying capability, the colloidal alumina also provides the substantial merits that a pasting property (ability to adhere materials to the substrate by adhesives and a writing property, which a noncoated support does not possess, are obtained.

The method employed in this specification to rate the microwave drying capability of water-proof papers is as follows: a water-proof paper is subjected to a development processing by an usual development processing as shown in FIG. 1, and the non-dried, processes waterproof paper is dried by means of a microwave heating apparatus shown in FIG. 2.

In FIG. 1, numeral 1 denotes a water-proof photographic paper wound as a roll and 2 denotes a development processing bath.

It is to be specifically noted that no criticality is attached to the development processing of the present invention and any developing known to the art for the emulsion involved (any photographic emulsion may, of course, be used) can be used.

In FIG. 2, numeral 3 denotes a microwave generator, 4 denotes a waveguide, and 5 denotes a water-proof photographic paper which has been subjected to development processing. In FIGS. 1 and 2, the water-proof photographic paper runs in the direction indicated by the arrow.

The microwave drying capability was rated by examining the relationship between both the oscillation power and the velocity of the microwaves traveling through the waveguide and the state of the dried surface of the water-proof photographic paper.

The microwaves can be of any type known to the art which provide a sufficient drying effect. Preferably, and this range includes commercially available microwave sources, the microwaves have a frequency of about 900 MHZ to 2,500 MHz.

The present invention will now be illustrated in greater detail by several non-limiting examples of preferred embodiments of the invention.

In all examples the microwaves used were of a frequency of 900 MHz to 2,500 MHz.

In Examples 1 3 the polyolefins were coated by extrusion coating. In Example 4 the paper base was covered by preformed polypropylene films on both sides.

EXAMPLE 1 Both sides of a photographic paper weighing 180 g/m were laminated with polyethylene (density 0.92, melting index 2.6), ata thickness of 30 p. to prepare support A. A colloidal alumina solution having the following composition was applied to the back of support A to prepare support B.

ALUMINA SOL-* (colloidal alumina 'made by Nissan Chemicals Industries, Ltd.)

-Continued Methanol 2 liter (the composition of ALUMINA SOL-100 is it) wtfk M 2 wL'Z HCl and 88 wt. water. size is in the range I my, to llKIll mp.)

The amount of solid ingredients coated to prepare support B was 1.0 g/m To each of support A and support B was applied the same emulsion for color photographic paper to thereby prepare two water-proof color photographic papers.

The thus obtained water-proof color photographic papers were exposed and subjected to development processing using a standard commercial color developer and the apparatus shown in FIG. 1 and subsequently dried by means of the microwave drier shown in FIG. 2. The relationship between the running rate of the water-proof photographic paper being dried and the state of the dried surface was examined while set- -Continued Potassium bromide 4 2 Water I l After developing and water-washing, the paper was fixed in the following solution for 4 min.

Sodium thiosulfate (anhydride) Sodium sulfite (anhydride) Water 350g lOg ll Thiourea 60 g ting the power of the microwave generator at 1.5 KW. Potassium bromide 30 g The results shown in Table l were obtained. Hydrochlorlc acld 30 ml 2-amino-3-hydroxyphenadine 0.0 ll Table 1 Water I I Support State of dried Running rate r surface m/ iin. The paper was washed with water and then sub ected 1 2 4 to silver-bleaching in the following solution. A At the back 0 0 e e Blister G O O O B At the back O O O O Blister O O O O Crystalline copper sulfate 100 g Hydrochloric acid In this and the following examples, O in the line At the Back means that the back of the paper is dried, while 6 means that the back of the paper is still wet or water drops remain on the back. Also, O in the line Blister means that no blisters formed on the back of the paper, while e means that blisters formed on the back of the paper.

As is clear from Table l, in the water-proof photographic paper where support A is used the drying conditions where no blisters formed on the back of the paper and complete drying is attained is narrow, whereas in the water-proof photographic paper wherein support B is used the range of drying conditions is wide, the drying velocity is large and, in addition, blisters on the back of the paper do not occur. Preparation of Color Photographic Emulsion Used 0.2 g of magenta coupler, 4-(3',5-dibutyloxycarbonylphenyl azo )-5-amino-l-naphthol, was dissolved in 2 ml of tricresylphosphate. The solution was added to a 10% by weight aqueous gelatin solution containing 2 ml of a 10 weight aqueous sodium alkyl benzene sulfonate solution and then the mixture was subjected to homogenizing to emulsify. Six g of the resulting emulsion was mixed with 20 g of a silver chlorobromide photographic emulsion containing about 30 g of silver bromide per 1 kg of the emulsion to provide the final emulsion.

Development Processing Used After exposing, the color papers were developed in the solutions having the following compositions for 10 minutes;

Sodium carbonate ml Water 1 l The paper was then washed with water, fixed in the fixing bath, washed again and then dried.

By the above treatment, a magenta image having completely bleached halide portions was obtained.

This material was favorable for the magenta component image of a malti-colored photosensitive material.

EXAMPLE 2 Both sides of a high quality paper weighing g/m were laminated with polyethylene (density 0.96, melt index 15) at a thickness of 30 u to prepare support C. On the other hand, the back of support C was subjected to corona discharge treatment at a discharge output of 4 KW and a discharge treating velocity of 100 m/min., and subsequently coated with a solution having the following composition to prepare support D.

ALUMlNA SOL-I00, as in Example I 2 kg MOVINYL DMlH*( polyvinyl acetate emulsion, made by Hoechst 0.01 kg Gosei K.K.)

Water 8 liter (39 wt.% polyvinyl acetate and 70 wt.% water) The amount of solid ingredients coated to prepare support D was 0.3 g/m To each of support C and support D was applied the same emulsion for black-andwhite photographic paper to produce water-proof photographic papers. The thus obtained waterproof photographic papers were subjected to development processing and dried using the same apparatus as was used in Example I. In this example, the power of the microwave generator was set at 3.0 KW, and the relationship between the running rate of the water-proof photo- ALUMINA SOL-200*(colloidal alumina made by Nissan Chemicals Industries, Ltd.)

. 7 8 graphic paper in the drier and the state of dried surface Cominued was examined. The results shown in Table 2 were obtamed g SNOWTEX-O**(colloidal silica made 2 kg by Nissan Chemicals Industries, Ltd.)

Table 2 Methanol 10 liters I 5 pp 8mm of dried Running rate 2; 2 wt.'7r acetic acid and 88 wt)? water, size is in the range l mu Surface' 1 "3"" 4 mm Wm SiO anJ so wt water) C back 8 g g g 0 The amount of colloidal alumina coated to prepare D A! the back O O O support F was 0.4 g/m To each of support E and sup- 3 O O O 0 port F was applied the'same emulsion for color photo- V v graphic paper as was used in Example 1 to produce wa- As is evident from Table 2, in the water-proof paper ter'proof P Q f P P p whlch' after pwherein support C is used there is observed either reent processing in the apparatus of FIG. 1 using a demaining water drops on the back or the formation of Veloper as Example 1, were mlcmwaves' blisters on the back under any drying conditions, which in the Same manner as in EXamPle In this mpl virtually makes 'microwave drying impossible. In conthe power of the microwave generator was 2.0 KW. trast, in the water-proof photographic paper wherein The relationship between the drying velocity and the pp D 15 used, the State of the (med Surface 15 g state of the dried surface was examined. The results obeven when the running rate of the water-proof phototamed are Shown in Table graphic paper, i.e., drying velocity, is as large as 5 m/min. Thus, the effects of coating the alumina sol to T the back of support are seen to be highly beneficial. 2 Composition of Black & White Photographic Emulsion 5 ppo Sta e of d ied Running rate Used surface (m/min.)

Silver chlorobromide containing E $2 1 back 3 g g g 50 mole of silver bromide 28 g (particle size: 0.6 micron) 30 F A, the back 0 o o -O Gelatin 120 g BIlSIel' O O O O 6 weight aqueous saponin solution 2.5 cc 5 weight aqueous chromium alum 5 cc solution I 6 weight aqueous formaldehyde 10 cc From Table 3 it is seen that the effects of coatlng the $212? to 1000 cc back of the support in accordance with the present invention are evident. The composition of the developer used EXAMPLE 4 w h I h l A I 5 40 Polypropylene films 20 p. inthickness (density 0.91) t t golgieumysaulililsgnfil;grige su ae) 450 g were laminated on both sides of a paper for photo- Hydroquinone l g-8 g graph c use weighing 200 g/m to prepare support G. 132%: l hydrate) 210 Z Separately, a solution having the following composition Water I 10 3000 cc was applied to the back of support G to prepare support l-l.

' EXAMPLE 3 The surface of a high quality art paper weighing 300 g/m was laminated with polyethylene (density 0.92 I ALUMINA SOL-200 2 l g/cm", melt index 25) and the back thereof was lami- Methaml 200 mm nated with a mixture of polyethylene (same as above) (0.8 part byweight) and polypropylene (0.2 part by g weight) of (density 092 glcma melt index 4) each The amount of collczldal alumina coated to prepare layer of a thickness of 30 u, to prepare support E. Sepav PP F g/ To each of 511M301t G and P rately, the back of support E was subjected to corona port H wasapplied the same emulsion for color photodischarge treatment at a corona discharge treating vegraphic paper as was used in Example 1 to produce walocity of 100 m/min. and subsequently coated with a t f photographic papers. The resulting photo-' s having thefollowmg smf 2 P graphic papers were subjected to-a development prosupport F. The'strength of the corona discharge treatessing by means 20f the development processing-111% Kw per Z' P- expresseclijas chine shown in FIG. 1 using a developer as inExample decimal power. S t b Smfce t ggigg l, and then the nondried, water-proof photographic pa- S 5 charge Y iz it i g g at: e perswere dried by passing them through a microwave pose o g drier as shown in FIG. 2. In this example, the state of the dried surface was examined by changing the power of the microwave oscillation while fixing the running rate of the paper in the microwave drier to bel m/min.

Table 4 Support State of dried Power of oscillation surface (KW) At the hack Q Q 0 O Blister O O O Q H At the back O O O O Blister O O O O From Table 4, it is seen that coating of alumina on the back of the support prevents the formation of blisters and, in addition, the back can be dried with micro waves of low energy.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

What is claimed is:

l. A photographic light-sensitive material comprising a. a support which comprises a polyolefin-laminated paper having on its back a coating layer composed of fibrous colloidal alumina (hydrate), and

b. a silver halide emulsion layer on the side of said support opposite the alumina coated side.

2. A photographic light-sensitive material as claimed in claim 1, wherein both surfaces of said paper are polyolefin coated.

3. A photographic light-sensitive material as claimed in claim 1, wherein the thickness of a polyolefin layer on said paper is from to 100 ,u.

4. A photographic light-sensitive material as claimed in claim 1, wherein said polyolefin is polyethylene, polypropylene or ,a mixture of polyethylene and polypropylene.

5. A photographic light-sensitive material as claimed in claim 1, wherein the size of the alumina is from 1 to 1,000 mu.

6. A photographic light-sensitive material as claimed in claim 1, wherein the coating amount of alumina is 10 more than 0.05 g/m 7. A photographic light-sensitive material as claimed in claim 5, wherein the size of the alumina is from 10 12. A photographic light-sensitive material as claimed in claim 1, wherein the polyolefin is polyethylenepolypropylene mixture.

13. A photographic light-sensitive material as claimed in claim 4, wherein the polyethylene has a density of about 0.91 to about 0.97 and a melt index of about 1 to about 30 and the polypropylene has a density of about 0.88 to about 0.91 and a melt index of about 0.1 to about 20.

14. A photographic light-sensitive material as claimed in claim 4, wherein:

a. the paper has a weight of g/m to 300 g/m and is coated on both sides with a polyolefin layer; b. a polyolefin layer is 10 to 100 ,a thick; c. the alumina has a size of 1 my. to 1,000 mu; d. the alumina is present in a layer consisting essentially of alumina in an amount of 0.05 to l g/m esthe polyethylene has a density of from about 0.91 to about 0.97 and a melt index of from about 1 to about 30; and f. the polypropylene has a density of from about 0.88 to about 0.91 and a melt index of from about 0.1

to about 20.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3, 884, 692

DATED May 20, I975 INVENTO R(S) Nobuhiko MINAGA WA It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below: 4 O

IN THE SPECIFICATION:

Column 3, line 53 delete "3, 53, 922" and insert 3, 253, 922

Q Signed and Scaled this twenty-first D 3.) Of October 1975 [SEAL] Attest:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner ufParenrs and Trademarks

Claims

1. A PHOTOGRAPHIC LIGHT-SENSITIVE MATERIAL COMPRISING A. A SUPPORT WHICH COMPRISES A POLYOLEFIN-LAMINATED PAPER HAVING ON ITS BACK A COATING LAYER COMPOSED OF FIBROUS COLLOIDAL ALUMINA (HYDRATE), AND

3. A photographic light-sensitive material as claimed in claim 1, wherein the thickness of a polyolefin layer on said paper is from 10 to 100 Mu .

4. A photographic light-sensitive material as claimed in claim 1, wherein said polyolefin is polyethylene, polypropylene or a mixture of polyethylene and polypropylene.

5. A photographic light-sensitive material as claimed in claim 1, wherein the size of the alumina is from 1 to 1,000 m Mu .

6. A photographic light-sensitive material as claimed in claim 1, wherein the coating amount of alumina is more than 0.05 g/m2.

7. A photographic light-sensitive material as claimed in claim 5, wherein the size of the alumina is from 10 to 100 m Mu .

8. A photographic light-sensitive material as claimed in claim 6, wherein the coating amount of alumina is less than 1 g/m2.

9. A photographic light-sensitive material as claimed in claim 1, wherein the paper has a weight of 100 g/m2 to 300 g/m2.

10. A photographic light-sensitive material as claimed in claim 1, wherein the support polyolefin is polyethylene.

11. A photographic light-sensitive material as claimed in claim 1, wherein the polyolefin is polypropylene.

12. A photographic light-sensitive material as claimed in claim 1, wherein the polyolefin is polyethylenepolypropylene mixture.

14. A photographic light-sensitive material as claimed in claim 4, wherein: a. the paper has a weight of 100 g/m2 to 300 g/m2 and is coated on both sides with a polyolefin layer; b. a polyolefin layer is 10 to 100 Mu thick; c. the alumina has a size of 1 m Mu to 1,000 m Mu ; d. the alumina is present in a layer consisting essentially of alumina in an amount of 0.05 to 1 g/m2; e. the polyethylene has a density of from about 0.91 to about 0.97 and a melt index of from about 1 to about 30; and f. the polypropylene has a density of from about 0.88 to about 0.91 and a melt index of from about 0.1 to about 20.