JPH02223945A - Production of photographic substrate - Google Patents

Abstract

PURPOSE:To obviate the generation of stains in a production process without degrading flatness by subjecting the surface of raw paper to a heating treatment at a specific temp. for a specific period of time prior to a corona discharge treatment. CONSTITUTION:The raw paper to be used for the photographic substrate is essentially required to be added with an alkyl ketene dimer as a sizing agent among additives. This photographic substrate is formed by subjecting the raw paper to the corona discharge treatment, then extrusion coating a polyolefin resin on both surfaces thereof. The surface of the raw paper is subjected to the heating treatment for 0.5 to 20 seconds at the temp. higher by >=10 deg.C than the m. p. of the alkyl ketene dimer prior to the corona discharge treatment of this time. When the corona discharge treatment is executed, sticking of the alkyl ketene dimer to a corona treatment roll and a pass roll with which the raw paper web after the corona discharge treatment comes into contact first and the consequent contamination of the rolls are obviated in this way.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing a photographic support in which both sides of a base paper are coated with a polyolefin resin. In the production of a photographic support in which both sides of a base paper containing an alkyl ketene dimer are fully coated with a polyolefin resin in order to completely prevent edge stains due to infiltration of developer from the cut surface of the support, in the polyolefin resin coating step. This invention relates to a method VC for producing a photographic support that prevents staining by alkyl ketene dimers.

(Prior Art) Conventionally, so-called baryta paper, in which one side of the paper is coated with a baryta layer mainly composed of barium sulfate, has been used as a support for photographic paper, but in order to automate and speed up the development process, Waterproof photographic paper, in which both sides of the base paper are coated with a hydrophobic polyolefin layer, has come to be used and now accounts for the majority of paper.However, even when all of the above waterproof photographic papers are used, the base paper TMV is still hydrophilic. Because it uses wood pulp gold, the developer solution will not penetrate from the cut surface (the edge stains at the edges of the photographic paper will be raw).The edge stains will be significantly reduced if you rinse the developer solution with water for a long time, but the developer This goes against the demand for processing to be carried out in a short time, and for this reason, there was a strong desire to prevent the developer from entering from the cut surface.As a method to prevent the developer from entering, the base paper contains a sizing agent. However, the types of sizing agents that can be used are subject to various restrictions due to the special use of photographic paper. It must have a size effect on both of the following: It must not reduce the whiteness of the photographic paper. It must not have any negative effects on the photograph, such as fogging. For this reason, it is generally used as a paper sizing agent. A, gin-based or petroleum resin-based sizing agents are not used.

Higher fatty acid type sizing agents as shown in Tokko Akihiro 7-Koburi 4/No., US special RFZ, Koda 1. As shown in it (wax type sizing agent or JP-A-Shoj/
-/l (Although alkyl ketene dimers and the like have been used as sizing agents for photographic paper supports, they each have their own drawbacks and are not sufficient.
Higher fatty acid type sizing agents are relatively effective in sizing against alcohol intrusion in developing solutions, but are not sufficient against alkaline solutions. In addition, it is affected by the quality of the water used when manufacturing paper, and if the water is hard, it will cause sedimentation, which will cause stains in the process, so it has the disadvantage that it cannot be used for multi-wrinkle production. Similar to higher fatty acid type sizing agents, wax-type sizing agents have a relatively effective sizing effect against the infiltration of alcohol, but are insufficient against alkaline liquid.

- In the case of alkyl ketene dimers, the size effect against alcohol in the developer is low, but the size effect against alkaline solutions is extremely excellent, and the alcohol resistance of systems using this alkyl ketene dimer can be improved. Many proposals have been made.

In other words, along with alkyl ketene dimers, higher fatty acid salts, paraffin wax, epoxidized fatty acid amides,
Methods of using alcohol-resistant chemicals such as polyacrylamide in combination and methods of increasing the chain length of the alkyl group of alkyl ketene dimers have been disclosed, and both methods have shown great improvement in preventing edge staining. .

For polyolefin coating on both sides of base paper, melt extrusion coating is used for boat fishing, and many improvements have been made to improve the adhesion between base paper and polyolefin. In other words, increasing the polyolefin melting temperature, increasing the nip pressure during coating,
Alternatively, it has been proposed to apply an anchoring agent to the base paper, to perform flame treatment, or to perform corona discharge treatment, but among these, corona discharge treatment has the greatest effect and has come to be widely used. .

However, if the base paper containing the aforementioned alkyl ketene dimer is subjected to corona discharge treatment after aging, the alkyl ketene dimer will adhere to the corona discharge treatment roll and the nozzle that first comes into contact with the base paper web after corona discharge treatment. It became clear that the problem of contamination occurred. For this reason, the amount of alkyl ketene dimer added, which has a large size effect, is limited. Also, as a countermeasure against spores 1, etc., polyolefin coating is performed immediately after paper making, or anchor coating treatment is performed instead of corona discharge treatment.

(Problems to be Solved by the Invention) However, the above-mentioned measures are not preferable because they are subject to various manufacturing limitations and also cause quality problems such as deterioration of flatness, especially in the case of anchor coating treatment. .

The inventors of the present invention have conducted intensive studies to solve these drawbacks, and have found that, prior to corona discharge treatment of base paper containing alkyl ketene dimers, the surface of the base paper is heated at a temperature of 1000 degrees or more above the melting point of the alkyl ketene dimers. It has been discovered that the above problem can be solved by heat treatment, and the present invention has been achieved.

Therefore, an object of the present invention is to provide a method for manufacturing a photographic support in which both sides of a base paper containing an alkyl ketene dimer are coated with a polyolefin resin to prevent edge stains, without deteriorating the flatness of the photographic support. To provide an entire photographic support that does not cause stains and is cost-effective (C).

(Means for Solving All Problems 2: Non-explosion ψ) The purpose of the above is to produce a photographic support by applying a corona discharge treatment to a base paper containing alkyl ketene dimers, and then coating both sides of the base paper with a polyolefin resin. In this method, prior to the corona discharge treatment, the surface of the base paper was heat-treated for O,S~][theta] seconds at a temperature 7,000 or more higher than the melting point of the alkyl ketene dimer.

The present invention will be explained in more detail below.

The base paper used for the photographic support according to the present invention is made of softwood,
It is obtained by making a whole stock paper by adding the chemicals described below to the main raw material of natural pulp selected from broad fruit trees, etc.

Synthetic pulp may be used instead of the natural pulp, or a mixture of natural pulp and synthetic pulp in any ratio may be used. Short fibers, broad-leaved bulbs ftO sub-mouse%
It is preferable to use the above.

Additive chemicals include, in addition to the alkyl ketene dimer mentioned above, clay, Merck, calcium carbonate, fillers such as urea resin fine particles, rosin, higher fatty acid salts, paraffin wax, sizing agents such as alkenyl succinic acid, and paper such as polyacrylamide. Those to which a fixing agent such as a force enhancer, sulfuric acid bandate, etc. are added are used.

In addition, Dye-1 fluorescent stain, slime control agent, antifoaming agent, etc. may be added as necessary. Further, all of the following softeners can be added as required.

Regarding the softening agent, an example is described in the New Paper Processing Handbook (edited by Shigyo Times Co., Ltd.), published in 2010.Those with a molecule of J200 or more are particularly preferred. That is, it has a hydrophobic group with a carbon number of IQ or more, and also has an amine salt or a high class ammonium salt that self-fixes with cellulose.

Specific VCs include reaction products of maleic anhydride copolymer and polyalkylene polyamine, reaction products of higher fatty acid and polyalkylene polyamine, reaction products of urethane alcohol and alkylating agent, ≠ grade ammonium salts of higher fatty acids, etc. Among them, a reaction product of a maleic anhydride copolymer and a polyalkylene polyamine, and a reaction product of a urethane alcohol and an alkylating agent are particularly preferred.

Among the above additives, it is essential to add alkyl ketene dimer as a sizing agent, and as mentioned above, from the viewpoint of preventing edge staining during development processing, θ, / ~ 1
．． Yuden weight percent, preferably θ. 3~/, θ overlapping percent is added.

Further, the longer the chain length of the alkyl group of the alkyl ketene dimer, the greater the effect on edge staining, and it is preferable. Ordinary alkyl ketene dimers contain approximately equal amounts of stearic acid and palmitic acid as raw materials (the melting point of the alkyl ketene dimer is 70C), while those containing behenic acid as the main ingredient (the melting point of the alkyl ketene dimer +, t'
e) is particularly preferred. As a method for incorporating the alkyl ketene dimer into the base paper, the alkyl ketene dimer is added in the form of an emulsion prepared by emulsifying it with cationic starch or the like to the paper t1 having a pulp density of Q and a weight of J' to 4%.

The surface of the pulp can also be subjected to surface size treatment with a film-forming polymer such as gelatin, starch, carboxymethylcellulose, polyacrylamide, polyvinyl alcohol, or a modified product of polyvinyl alcohol. Examples of polyvinyl alcohol modified products in this case include carboxyl Mfa products, silanol modified products, and copolymers with acrylamide. Further, when surface size treatment is performed using a film-forming polymer, the coating amount of the film-forming polymer is θ, /-j, 09/m, preferably O1
Evening~ko 0,! Adjusted to il/rn 2. In this case, an antistatic agent, a fluorescent whitening agent, a pigment, an antifoaming agent, etc. can be added to the film-forming polymer as necessary.

In addition, the base paper is made from a pulp slurry containing the above-mentioned pulp and additives such as filler, sizing agent, paper strength reinforcing agent, fixing agent, etc. added as necessary, using a paper machine such as a Fourdrinier paper machine. It is manufactured by drying, rolling and rolling. The above-mentioned surface size treatment is performed either before or after this drying, and calender treatment is performed after drying or during winding.

If the surface size treatment is carried out after drying, this calender treatment can be carried out either before or after the surface size treatment, but in order to effectively achieve the object of the present invention, It is preferable to perform such calendar processing in the final finishing step after performing various processing.

In the calendering process according to the present invention, metal rolls,
As the elastic arule, a known one used in the production of ordinary paper is used.

The base paper used for the photographic paper support of the present invention is subjected to the above-mentioned calendar treatment, and finally! O~ko! Qμm
is adjusted to

The density of the base paper is o, rt, ip7cm3, preferably /, 0-/, ip9/cm2.

The photographic support according to the present invention is prepared by subjecting the base paper to a corona discharge treatment and then extruding and coating both sides of the base paper with a polyolefin resin. The heat treatment is performed at a temperature touc or higher than the melting point, preferably 20°C or higher. The higher the heat treatment temperature, the more effective it is against roll stains in a short treatment time.
”Since deterioration of the flatness of the base paper was observed when cutting the c.
'cf! - It is preferable not to get angry. As a method of heat treatment, contact with a heating drum, blowing of hot air, heating with microwaves, flame treatment, etc. are possible, but contact with a heating drum is particularly efficient and preferred. The treatment time varies depending on the temperature, but is preferably 0.15 to 20 seconds.

) Examples of polyolefin resins include polymers of α-olefins such as polyethylene and polypropylene, and mixtures of these various polymers. Particularly preferred polyolefins are high density polyethylene, low density polyethylene and mixtures thereof. There is no particular restriction on the molecular weight of these polyolefins as long as they can be extrusion coated, but polyolefins having a molecular weight in the range of 2o, ooo to cooo, ooo are usually used.

There is no particular limit to the thickness of the polyolefin resin coating layer (although it can be determined according to the thickness of the polyolefin resin coating layer for conventional photographic paper supports, it is usually l~!~!).
Qμm is preferred.

Known additives such as white pigments, colored pigments, fluorescent whitening agents, and antioxidants can be added to the polyolefin resin layer. In particular, it is preferable to add a white pigment and a colored pigment to the polyolefin resin coating layer on the surface to which the photographic emulsion is applied.

Note that when extrusion coating polyolefin, a conventional extruder and laminator for polyolefin are used as extrusion coating equipment.

The support for photographic stamp 1IkI paper of the present invention is further coated with a photographic emulsion layer on one side and dried to become a photographic photographic paper. Various embodiments are possible, such as the possibility of providing layers.

(Effects of the Invention) According to the present invention, when corona discharge treatment is performed on base paper containing alkyl ketene dimers, the alkyl ketene dimer is added to the nozzle that the corona treatment roll and the base paper web after corona discharge treatment first come into contact with. It is possible to solve the problem of staining due to adhesion to the product, and to avoid appearance defects due to transfer to the product. However, the present invention is not limited to these embodiments.

Example I A wood pulp consisting of 30 parts of L88P and LBK/'Pyo parts was beaten with a Discri 7 Einer and Canadian Freeness soo, cc-1, and 0.7 parts of sodium stearate, 1.3 parts of anionic polyacrylamide, 2.0 parts of aluminum sulfate, polyamide polyamine epichlorohydrin, tg, and alkyl ketene dimer (melting point guar °C) o and r parts were added in the absolute dry weight ratio to the wood bulb, and the mixture was processed using a Fourdrinier paper machine. t/yoθg/m
A base paper with a thickness of 1UOμ was made. After aging for IQ days, both sides of this base paper were extrusion coated with polyolefin resin. Corona discharge treatment during polyolefin coating (Prior to this, heat treatment was performed on the base paper surface (both front and back sides) for 2 seconds using a QoC heating drum. No stains were generated on the corona treatment roll and pass roll. There was no problem.The coated polyolefin resin is as follows.T, that is, the front mountain on which the photographic emulsion layer is provided] 11th cut is LDPE/HDPE containing T i 02 of /θ sub-weight percent.
The back side was coated with LDPE/HDPE=, ZO/rO (D polyethylene:/f26 micron).

Comparative Example 1 When the base paper of Example 1 was subjected to corona discharge treatment without heat treatment before corona discharge treatment, alkyl ketene dimer was found on the corona treatment roll and the first e-spool after corona treatment. Contamination occurred.

Example 2 Anionic polyacrylic 7410 was added to the beaten paper stock of Example 1.
Part 7, cationic polyacrylamide Q.

7 parts, polyamide polyamine epichlorohydrin o, r
1 part, 0.3 part of epoxidized fatty acid amide, and 0.7 part of alkyl ketene dimer (melting point A, t'C), all in the absolute dry weight ratio to the bulb, and paper was made in the same manner as in Example 1 to prepare base paper 7. did. After aging this base paper for 1 day, Example 1
Corona discharge treatment and polyolefin coating were performed in the same manner as above. Heat treatment prior to corona discharge is
/θQ0C heating drum7. There are γC rows for j seconds. As in Example 1, no staining of the corona-treated roll or pass roll occurred.

Comparative Example 2 Using the same base paper as in Example 2, corona discharge treatment was performed without heat treatment before corona discharge, and the corona treatment roll and JIIl first pass roll after corona treatment were stained by alkyl ketene dimer. There has occurred. The degree of contamination is one pretension compared to Comparative Example 1.

From the results of Examples and Comparisons of 4 Parts and 2 Examples, after corona discharge treatment was applied to the base paper containing alkyl ketene dimer gold in the paper,
It is clear that the manufacturing method according to the present invention is extremely good in terms of process stability in the manufacturing method of photographic supports that are coated with polyolefin.

Claims (3)

[Claims] (1) In a method for producing a photographic support in which a base paper containing an alkyl ketene dimer is subjected to a corona discharge treatment and then both sides of the base paper are coated with a polyolefin resin, the alkyl ketene dimer is applied to the surface of the base paper prior to the corona discharge treatment. A method for producing a photographic support, which comprises performing a heat treatment for 0.5 to 20 seconds at a temperature 10°C or more higher than the melting point. (2) The method for producing a photographic support according to claim (1), wherein the alkyl ketene dimer content in the base paper is 0.1 percent or more based on the weight of the pulp. (3) The method for producing a photographic support according to claim (1), wherein the alkyl ketene dimer has a melting point of 40 to 80°C.