JPS60181131A - Production of master batch for photography, and manufacture of resin-coated paper for photography - Google Patents

Abstract

PURPOSE:To obtain a coated paper resistant to the generation of microgrits on the surface of a photograph, by diluting a master batch containing titanium dioxide pigment at a high concentration to obtain a master batch having low concentration, and combining the master batch with a specific dilution resin. CONSTITUTION:The object master batch for photographing use and containing a resin and a titanium dioxide pigment is prepared by the following process. A high-concentration resin composition (acid-free) containing titanium dioxide pigment at a concentration higher than the titanium dioxide pigment concentration in the objective master batch is diluted with a dilution resin to obtain a low-concentration composition containing the titanium dioxide pigment at a lower concentration than the above high-concentration resin composition and at a higher concentration than the resin composition to be used in the production of a coated paper. The obtained low-concentration composition is diluted with a dilution resin having a melt index of 2-9, and applied to a sheet of paper or synthetic paper base by extrusion. The titanium dioxide pigment contents in the high-concentration composition, the low-concentration composition and the resin composition to be used in the coated paper production are 40-80pts.(wt.), 20-60pts. and 5-20pts., respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a photographic masterbatch, and more particularly to a method for producing a photographic masterbatch (microgrits) using the photographic masterbatch.
The present invention relates to a method for producing photographic resin-covered paper with extremely low cro grit.

The essential structure of a photographic resin-coated paper containing a photographic masterbatch in a resin layer is already known; for example, as disclosed in U.S. Pat. No. 3,501,298, both sides of a paper base are coated with a resin. However, the resin layer on the side to which the emulsion is coated contains all of the titanium dioxide pigment, blue pigment, fluorescent whitening agent, and the like.

However, in the manufacturing method of photographic resin-coated paper,
The reality is that sufficient measures have not yet been taken to effectively prevent the generation of microgrit.

The term "microgrit" as used herein refers to microscopic foreign matter or microscopic particles that appear on the surface of the coated resin in photographic resin-coated paper in which at least one side of the paper or synthetic paper base is coated with a resin composition. .

There are various main causes of microgrit, but for example, the main cause of microgrit that appears on photographic resin-coated paper manufactured by melt-extruding photographic resin onto at least one side of a paper or synthetic paper substrate using a melt-extruder is as follows: (1) If the resin used itself generates a lot of gel, (2)
When the molten resin is extruded into a film from the bath melt extruder through the die, if the proper temperature cannot be maintained and the flow is uneven, (3) If the screen you are using is dirty, (4)
Examples include cracks in the barrel liner in the melt extruder, and (5) insufficient bending in the melt extruder, but these can often be resolved relatively easily by skilled engineers. .

However, the most difficult countermeasure against microgrit is when microgrit occurs in photographic resin-coated paper in which the paper or synthetic paper substrate is coated with a resin composition consisting of at least a resin and a pigment.

In the first place, the method of incorporating pigments into resin is to create a so-called masterbatch in which the pigments are included in the entire resin at a constant concentration, and then dilute and mix them with a diluent resin to the desired ratio. It is usual to prepare and use a so-called compound in which a desired composition ratio of the compound is contained in a resin from the beginning.

However, when preparing a masterbatch or Konnokurand by melt-kneading resin and pigment using an ordinary melt mixer such as a Banbury mixer or a kneader, relatively coarse pigments may be present in the resin. Particles tend to be dispersed as they are without being dispersed into a fine state.
Thus, undispersed pigment particles will be present in the masterbatch or compound. As a result, at least one surface of the paper or synthetic paper substrate is coated with a resin composition comprising at least a pigment and a resin produced using the masterbatch or the compound. microgrit will be generated.

The occurrence of microgrit in resin-coated papers used as photographic supports causes serious photographic defects.

That is, when a person is photographed on a photographic paper having microgrit-generated resin-coated paper as a photographic support, if microgrit appears in areas such as the face, the photograph has no commercial value.

As a result of various studies to improve these points, the present inventors have discovered a photographic masterbatch consisting of at least a resin and a titanium dioxide pigment, which can be used in photography without substantially containing an antioxidant. A titanium dioxide pigment-containing resin composition prepared in advance with a titanium dioxide pigment content higher than that of the masterbatch is prepared, and the titanium dioxide pigment content is lower than the titanium dioxide pigment content in the titanium dioxide pigment-containing composition,
and by applying it to a photographic resin-coated paper extrusion coated on one side of a whole paper or a synthetic paper substrate with a photographic masterbatch diluted with a diluent resin higher than the titanium dioxide pigment content in the resin composition used, It was discovered that the generation of microgrit was significantly suppressed, leading to the present invention.

It has been found that the effect is particularly significant when the resin used to dilute the photographic masterbatch has a melting index of 2 to 9.

Until now, the photographic masterbatch containing titanium dioxide pigment used for photographic resin-coated paper usually contains titanium dioxide pigment i20 to 40%! According to the quality of the photographic resin-coated paper required, at least one of the photographic resin-coated papers is used as a resin composition containing a desired titanium dioxide pigment content by appropriately blending a diluted resin. It was applied to the aspects of However, when producing photographic resin-coated paper by such a conventional method, microgrit is often generated, often resulting in deterioration in quality.

However, the photographic masterbatch is composed of at least a resin and a titanium dioxide pigment, and contains titanium dioxide pigment which is prepared in advance to have a titanium dioxide pigment content higher than that of the photographic masterbatch without substantially containing an antioxidant. composition (hereinafter referred to as high-concentration masterbatch), the total titanium di112 pigment content is lower than the titanium dioxide pigment content in the titanium dioxide pigment-containing composition. A photographic masterbatch diluted with a diluent resin that has a low titanium dioxide pigment content and is higher than the titanium dioxide pigment content in the resin composition used] (hereinafter, the words in brackets may be abbreviated as low-concentration masterbatch), whole paper or synthetic It has been found that by applying it to at least one side of the paper substrate, the generation of microgrit is significantly suppressed.

The high-concentration masterbatch referred to in the present invention is first diluted with a diluent resin to form a low-concentration masterbatch. After diluting the photographic masterbatch with a diluent resin having a melting index of 2 to 9, the paper or synthetic paper substrate is When extrusion coating is applied to at least one side of the paper or synthetic paper substrate, microscopic The reason why the generation of grit is significantly suppressed is still not clear, but it seems to be due to a special effect in combining a high concentration masterbatch with a low concentration masterbatch and then diluting the resin after waiting for a specific melting index. .

The melt index in the present invention is the melt index (M
It has the same meaning as I).

Incidentally, the generation of microgrit tends to be more likely to occur when the pigment in the masterbatch also contains ultramarine blue than when the pigment is a titanium dioxide pigment alone.

In the photographic industry, it is essential to apply ultramarine to the resin layer of photographic resin-coated paper in order to achieve a white appearance, which is called pluing, and an immediate solution is needed. It was wanted. In the present invention, particularly excellent results can be obtained not only when a titanium dioxide pigment is used alone, but also when a photographic masterbatch containing ultramarine blue is applied to the photographic resin-coated paper of the present invention.

As the ultramarine blue used in the present invention, any commercially available ultramarine blue can be used as long as it does not cause any problems when applied to photographic resin compositions. for example,
Dai-Kasei Kogyo Co., Ltd. Backguchi Gunyo A 8000, A40
00, A 3000, A 2000, Akakuchi Gunsoya 190
0, A 1500, A 300, processed ultramarine A3000
A, A1500AXPB-80, DV-1, DV-2, etc. In some cases, CB-80°, CB-50
Cosmetic ultramarines such as , DR-1, and DP-3 can also be used. In addition, various types of ultramarine may be used in appropriate combination to produce a desired color.

In the present invention, the amount of ultramarine contained in 100 parts by weight of the resin composition is preferably 0.05 to 10 parts by weight. If it exceeds 10 parts by weight, the generation of microgrit will be significantly increased, and if it is less than 0.05 parts by weight, the bluing effect will not be exhibited well.

In the present invention, the pigment content in the high concentration masterbatch is preferably 40 to 80 parts by weight, and the pigment content in the low concentration masterbatch is preferably 20 to 60 parts by weight.

The titanium dioxide pigment used in the practice of the present invention includes:
Those by sulfuric acid method, those by chlorine method, rutile type,
Any anatase type may be used, but the anatase type is advantageous in terms of whiteness. In addition, titanium dioxide pigments without surface treatment can be used, titanium dioxide pigments coated with an inorganic surface treatment agent such as hydrous aluminum oxide, or organic surface treatment agents such as orcappolysiloxane can be used. It is also possible to use a surface treated with a surface treatment agent, or a combination of an inorganic surface treatment agent and an organic surface treatment agent as appropriate.

The resin used in the photographic masterbatch (hereinafter sometimes abbreviated as MB) in the present invention may be any thermoplastic resin as long as it can be coated by melt extrusion, but polyolefin resins are particularly preferred; For example, polypropylene, high-density polyethylene, medium-density polyethylene, low-density polyethylene, or a combination of two or more of these resins can be used, and low-density polyethylene resin is particularly preferred.

As the diluting resin in the present invention, a polyolefin resin having a melting index of 2 to 9 is used. For example, polypropylene, polyethylene, etc. are used, and polyethylene is particularly preferred. As the polyethylene resin, high-density polyethylene, medium-density polyethylene, low-density polyethylene, etc. may all have a melting index of 2 to 9, or a combination of these resins with an 'e of 211 or more may be used.

The content of the titanium dioxide pigment used in the photographic resin composition of the present invention in the resin layer of the photographic resin-coated paper is 5% by weight or less based on the resin, so that it has a good hiding power as a photographic support. On the other hand, if it exceeds 40% by weight, the fluidity etc. decreases, which is not preferable, and particularly preferably 7.5% by weight to 25% by weight! It is within the range of 'chi'.

The resin coating of the photographic resin-coated paper of the present invention may contain a fatty acid metal salt. Examples of these fatty acid metal salts include zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, zirconium octylate, sodium palmitate, calcium palmitate, and sodium laurate. The amount added is preferably in the range of 0.01 to 5% by weight based on the resin composition containing the titanium dioxide pigment.

If necessary, the photographic resin composition of the present invention includes ridges,
White pigments such as zinc oxide, talc, and calcium carbonate, colored pigments such as cobalt blue, cobalt violet, and deep blue, and gold such as fluorescent whitening agents may be added.

The photographic resin-coated paper of the present invention is produced by melt-extruding a heated and melted resin composition onto at least one surface of a paper or synthetic paper base (hereinafter simply referred to as base paper) through a slit die in the form of a film. Usually, the melt extrusion temperature is preferably 200°C to 350°C.

Further, before coating the resin composition on the base paper, it is preferable to subject the base paper to an activation treatment such as a corona discharge treatment or a fire treatment. There is no particular limit to the thickness of the resin layer of the resin-coated paper, but it is generally advantageous to extrude coat it to a thickness of about 5 microns to 50 microns. In addition, in ordinary resin-coated paper, in which both sides of the base paper are coated with resin, the resin surface containing titanium dioxide pigment has a glossy surface, a matte surface, a silky surface, etc., depending on the use, and the opposite surface. The back surface of the side is usually a matte surface, and if necessary, the front surface or both the front and back surfaces can be subjected to activation treatment such as corona discharge treatment or fire treatment.

The base paper used in the practice of the present invention may be ordinary natural paper, synthetic fiber, or so-called synthetic paper made of synthetic resin film 6. Natural nokuru paper based on mixed pulp wood pulp is advantageously used. There are no particular restrictions on the thickness of the base paper, but it is preferable that the base paper has a smooth surface and has a basis weight of 50 to 250.
9/lt? 751 preferred.

The base paper containing natural noclub as a main component, which is advantageously used in the practice of the present invention, can contain various polymeric sieving agents. For example, as a dry paper strength enhancer,
Sizing agents such as cationized starch, cationic polyacrylamide, anionized polyacrylamide, carboxy-modified polyvinyl alcohol, gelatin, fatty acid salts, rosin derivatives, dialkyl ketene dimer emulsions, stone-based resin emulsions, styrene-maleic anhydride [
Ammonium salts of copolymer alkyl esters, etc. as pigments, clay, kaolin, calcium carbonate, barium sulfate, titanium oxide, etc. as wet paper strength enhancers, melamine resins, urea resins, epoxyhybolyamide resins, as fixing agents. , polyvalent metal salts such as aluminum sulfate and atubenium chloride, cationic modified polymers such as cationized starch, pH regulators such as caustic soda, soda carbonate, and hydrochloric acid, inorganic electrolytes such as common salt and mirabilite, dyes, and fluorescent substances. A whitening agent, latex, etc. can be contained in an appropriate combination.

The photographic resin-coated paper of the present invention can be provided with various silver halide photographic emulsion layers.

For example, silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide emulsions) can be provided. In addition, color couplers are contained in the silver halide photographic emulsion layer,
Multilayer silver halide photographic constituent layers can be formed into gold films. As the binder for these silver halide emulsion layers, in addition to ordinary gelatin, hydrophilic polymeric substances such as polyvinylpyrrolidone, polyvinyl alcohol, and polysaccharide sulfate ester compounds can be used. Further, the above-mentioned silver halide emulsion layer can contain various additives. For example, as sensitizing dyes, cyanine dyes, merocyanine dyes, etc.; as chemical sensitizers, water-soluble gold compounds, sulfur compounds, etc.; as anti-capri agents or stabilizers; hydroxy-triazolopyrimidine compounds, mercapto-compounds; Ring compounds, etc., as hardening agents, formalin,
Vinyl sulfone compounds, aziridine compounds, etc., as coating aids, benzene sulfonate, sulfosuccinic acid ester salts, etc., stain preventive agents, dialkylhydroquinone compounds, etc., development accelerators, hydroquinone, phenidone, etc., ultraviolet absorbers, benzene, etc. In addition to triazole compounds, fluorescent whitening agents, sharpness-enhancing dyes, antistatic agents, pH adjusters, and water-soluble iridium compounds and water-soluble rhodium compounds may be contained in appropriate combinations during the production and dispersion of silver halide. can.

Further, on the back side of the photographic resin-coated paper in the present invention, that is, on the support surface opposite to the side on which the photographic constituent layer, in most cases the silver halide photographic constituent layer, is coated, anti-curl, antistatic, etc. A coating layer consisting of a hydrophilic colloid layer called a backcoat layer can be provided for the purpose of preventing adhesion and smearing.

Such a bank coat layer may contain a binder, a protective colloid, a curing agent, an antistatic agent, a surfactant, a matting agent, a latex, and the like.

Next, examples will be described in order to explain the present invention more specifically.

Example 1 Low density polyethylene (density 0.92t/ad, MI=8
) 15ffitWk (into a saw mixer, add the amount of titanium dioxide pigment, amount of ultramarine, and amount of zinc stearate listed in Table 1, Note 1, respectively, and knead well at 150 ° C. Each obtained a high concentration master's goal.

Low-density polyethylene (density 0.92f/+!, MI=
8) and then melt-extruded using a vented extruder to obtain a low concentration masterbatch as shown in Table 1, Note 2.

Separately, a comparison mask was created as follows. That is, 57.5 parts by weight of low-density polyethylene i, the same as that used in sample boiling 4, was placed in a mixer (1) and 40 parts by weight of titanium dioxide pigment, 0.5 parts by weight of ultramarine, and zinc stearate were added. Add 2 parts by weight (all of these are the same as those used for samples A1 to 7), and add 15 parts by weight.
Knead well at 0°C to obtain a comparative masterbatch containing pigments, etc., which will be referred to as sample A8).

On the other hand, a mixed paper stock of 50 parts by weight of hardwood bleached kraft pulp and 50 parts by weight of softwood bleached sulfide pulp was beaten to Canadian Standard Freeness 310, and to 100 parts by weight of pulp, 3 parts by weight of cationized starch and anionic 0.2 parts by weight of polyacrylamide, alkyl ketene dimer emulsion (as ketene dimer content)
0.4 parts by weight of polyaminopolyamide epichlorohydrin resin were added to form paper having a basis weight of 160 f/-. The obtained wet paper was dried at 110° C., and subsequently mixed with 3 parts by weight of carboxy-modified polyvinyl alcohol, 0.05 parts by weight of a fluorescent brightener, 0.002 parts by weight of blue dye, 0.2 parts by weight of citric acid and 97 parts by weight of water. It was impregnated with an impregnating solution of 25 parts by weight, dried with hot air at 100°C, calendered at a linear pressure of 90 kg/cm, and then treated with corona discharge on both sides to form a base for photographic resin-coated paper. All paper was manufactured.

Next, apply high-density polyethylene (density 0.96
A 1:1 mixture of t/ld, MI=5) and low density polyethylene (density 0.92t/ctdXMI=5) was coated to a thickness of 30μ using a melt extrusion coating machine at a resin temperature of 330°C. . Next, a resin composition consisting of 25 parts by weight of MB described in Note 2 of Table 1 and 75 parts by weight of low-density polyethylene for dilution described in Note 3 of Table 1 was thoroughly mixed on the surface of the base paper, and then extruded as a set of screws with an extrusion opening diameter of 65 mm. machine and 750
■ Using a melt extruder with a wide T-die, the resin temperature is 3.
Each resin-coated paper containing titanium dioxide pigment and the like was produced by coating at 20° C. to a thickness of 30 μm. At that time, the surface resin layer containing titanium dioxide pigment etc. was processed into a flat glossy surface, and the back resin layer was processed into a paper-like matte surface.

The number of microgrits was determined by visually counting the number of microgrits generated on the resin surface containing titanium dioxide pigment, etc. of the photographic resin-coated paper produced by the method described above.

The results obtained are shown in Table 1.

Table 1 Note 1) (1) TiO2: Anatase-type titanium dioxide surface-treated with hydrous aluminum oxide (0.5% by weight calculated in the form of Az20.) (2) Ultramarine: Manufactured by Dai-Kasei Kogyo Co., Ltd. Kuchigunsoni 20
00 (3) Zn-st zinc nistearate From Table 1, the high-concentration masterbatch in the present invention is a low-concentration masterbatch in the resin composition combined with the low-density polyethylene for dilution described in Note 3. It can be seen that all samples No. 1 to No. 5 having a melting index (MI) of 2.5 to 9 have little microgrit generation. Further, it can be seen that samples A6 and A7, in which the Ml of the low density polyethylene for dilution is 12 and 20, generate more microgrit than the samples A~5.

On the other hand, in a masterbatch prepared from the beginning with a low concentration masterbatch, even if the MI of the diluent resin was 8, microgrit was generated in a large amount, and it was unsuitable as a photographic resin-covered paper.

Example 2 The resin, titanium dioxide pigment, group, and magnesium stearate were each placed in a Banbury mixer so that the contents were as shown in Table 2, Note 4, and the mixture was thoroughly kneaded at 150°C to obtain the pigments, etc. This highly concentrated masterbatch is a total bargain.

The high-concentration masterbatch obtained in this manner and an equal weight of medium-density polyethylene (density 0.93, MI = 6) were thoroughly mixed and then melt-extruded using a cross-wire extruder.
The low concentration masterbatches described in Note 5 were obtained.

Separately, the following masterbatch for comparison was prepared. That is, a total of 76.5 parts by weight of the same medium density polyethylene used in samples A10 to A14 was mixed in a Banbury mixer.
20 parts by weight of titanium dioxide pigment and 2 parts of ultramarine blue.
．． 5 parts by weight and 1 part by weight of magnesium stearate (both of which are the same as those used for Sample A 10-414) were added and kneaded well at 150°C to obtain a comparative masterbatch containing pigments, etc. ( Sample A15).

The procedure was the same as in Example 1, except that the resin composition used in melt extrusion using the extruder described in the Example was as shown in Table 2, note 6, line 9.

The results obtained are shown in Table 2.

Table 2 Note 4) (1) Resin: Medium density polyethylene (density 0.93, M
I=6) A 1500 (4) Mg-st Magnesium Nistearate Note 6) (1) MB: Low concentration master knot (2) LD
PE: Low density polyethylene (@ degree 0.92, Ml=3
) From Table 2, in the resin composition in which a low concentration masterbatch of high concentration masterbatch is combined with the low density polyethylene for dilution described in Note 6, the ultramarine content in the high concentration masterbatch. It can be seen that all the samples containing 0.05 to 10 parts by weight (samples AIO to A13) generate less microgrit.

On the other hand, for the high concentration masterbatch with an ultramarine blue content of 15 parts by weight (sample A14) and the comparative masterbatch (sample 15), even if the MI of the low density polyethylene for dilution was 3. However, many microgrits were generated, making it unsuitable for use as resin-coated paper for photography.

Example 3 55.6 parts by weight of the low-density polyethylene listed in Table 2, Note 6 in Samples A12 and 415 of Example 2 were added to 30.6 parts by weight of the low-density polyethylene and high-density polyethylene (density 0.97, MI = 7). ) Samples A12 and A15 of Example 2 were carried out in the same manner as Samples A12 and A15, except that 25 parts by weight of each was used, and the same results as in Example 2 were obtained.

Claims (1)

[Scope of Claims] 1. A photographic masterbatch comprising at least a resin and a titanium dioxide pigment, wherein the photographic masterbatch contains substantially no antioxidant and has a predetermined amount of titanium dioxide pigment in the photographic masterbatch. The highly prepared titanium dioxide pigment-containing resin composition is prepared such that the titanium dioxide pigment content is lower than the titanium dioxide pigment content in the titanium dioxide pigment-containing composition, and the dazzling titanium pigment in the used resin composition is used. A method for producing a photographic masterbatch in which the t% of the content is higher than that of a diluent resin. 2. The titanium dioxide pigment-containing resin composition of the photographic masterbatch prepared in advance has a titanium dioxide pigment content of 40 to 80 parts by weight, Claim 1 The method for producing a photographic masterbatch as described in Section 1. 3. The method for producing a photographic masterbatch according to claim 1, wherein the photographic masterbatch has a titanium dioxide pigment content of 20 to 60]i dobe. 4. The photographic masterbatch containing titanium dioxide pigment contains 0.05 to 10 parts by weight of ultramarine in 100 parts by weight of a titanium dioxide pigment-containing resin composition prepared in advance. How to make a photographic masterbatch. 5. In the production of photographic resin-coated paper in which at least one side of a paper or synthetic paper substrate is coated with a resin composition comprising at least a resin and a titanium dioxide pigment, a photograph comprising at least a resin and a titanium dioxide pigment is used. A titanium dioxide pigment-containing resin composition that is prepared in advance to have a titanium dioxide pigment content higher than that of the photographic masterbatch without substantially containing an antioxidant is added to the photographic masterbatch. A photographic masterbatch diluted with a diluent resin was diluted with a diluent resin, and the titanium dioxide pigment content was lower than the titanium dioxide pigment content in the titanium dioxide pigment-containing composition, but higher than the titanium dioxide pigment content in the resin composition used. A process for producing resin-covered photographic paper, which is then coated by extrusion on one side of a paper or synthetic paper substrate. 6. The titanium dioxide pigment content in the titanium dioxide pigment-containing resin composition, which is prepared in advance to be higher than the titanium dioxide pigment content of the photographic masterbatch used for the photographic resin-coated paper, is 40 to 80 M parts. The fifth claim is
Method for manufacturing resin-coated paper for photographs as described in Section 1. 7. The method for producing a photographic resin-covered paper according to claim 5, wherein the photographic masterbatch used for the photographic resin-covered paper has a titanium dioxide pigment content of 20 to 60 parts by weight. 8. 0.05 to 10 parts by weight of ultramarine was contained in 100 parts by weight of a titanium dioxide pigment-containing resin composition that had been prepared in advance to have a higher titanium dioxide pigment content than that of the photographic masterbatch used in the photographic resin-coated paper. A method for producing a photographic resin-covered paper according to claim 5. 9. The method for producing a photographic resin-coated paper according to claim 5, wherein the content of titanium dioxide pigment in the resin composition used during the production of the photographic resin-coated paper is 5 to 20 parts by weight. 10. A patent claim in which the diluting resin for diluting the photographic masterbatch used in the photographic resin-covered paper to the titanium dioxide pigment content in the resin composition used is a polyolefin resin with a melting index of 2 to 9. A method for producing a photographic resin-coated paper according to item 5.