JPH0841288A - Molded article for photosensitive material and resin composition used therefor - Google Patents

Abstract

PURPOSE:To obtain the composition useful as a magazine for housing a photosensitive material, having a reduced concentration of formaldehyde produced from a molded article, prepared not to damage photographic properties, comprising a polyacetal resin composition. CONSTITUTION:This composition comprises (A) 100 pts.wt. of a polyacetal resin, (B) 0.05-3.0wt.%, preferably 0.06-2.0wt.%, especially preferably 0.067-1.0wt.% of an active imino group-containing organic cyclic compound (preferably compound of hydantoins) and more preferably (C) 0.001-1.0wt.% of a hindered phenol-based antioxidant or (D) 0.05-25wt.% of a light-screening substance. The composition has <=20ppm concentration of formaldehyde generated from a molded article composed of the composition in a closed container. The composition is prepared so as not to damage photographic properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magazine for storing photographic light-sensitive materials such as photographic film and photographic paper, or molded products for photographic light-sensitive materials such as springs and rollers used around these photographic light-sensitive materials. And a molding resin composition used therefor.

[0002]

2. Description of the Related Art Polyacetal resin, which is a thermoplastic resin, has excellent mechanical properties, heat resistance, friction and wear resistance,
Due to its fatigue resistance, it is used as a molding material for bearings, gears, rollers, cams, clips, leaf springs of various devices. However, since a small amount of formaldehyde, which is the monomer, is dissolved in the molded product of the polyacetal resin, it is gradually released into the air, resulting in a deterioration of the work environment and a decrease in work efficiency. Depending on the purpose of use, various harmful effects may occur. For example, due to the presence of chemically active formaldehyde, polyacetal resins may be of concern for use in food and hygiene packaging and the like.

It is known that formaldehyde also has an adverse effect on photographic light-sensitive materials such as photographic film and photographic paper. Although silver halide emulsions are used in these photographic light-sensitive materials, formaldehyde acts to reduce silver halide, resulting in chemical fog. Therefore, it is generally impossible to use a polyacetal resin in a resin composition of various molded articles used in the magazines containing these photographic light-sensitive materials or in the vicinity thereof, and elasticity is required like a film pressure plate, for example. Metal parts were often used for parts.

Considering these circumstances, JP-A-4-345648 describes the use of a hydrazide compound as an additive in order to reduce the concentration of formaldehyde gas in an acetal resin molded article, and also JP-A-4-345648. The use of a fatty acid ester of a polyhydric alcohol compound as an additive is described in JP-A-6-107900.

[0005]

However, when a hydrazide compound is added as an additive to a polyacetal resin, its by-product hydrazine itself may act as a reducing agent on the photographic light-sensitive material, and the polyhydric compound has a high polyvalent content. When the fatty acid ester of an alcohol compound is used as an additive, the effect of reducing formaldehyde is insufficient, and there has been a practical problem as a resin composition for molded articles for photographic light-sensitive materials.

The present invention has been made to solve the above problems, and a polyacetal resin having excellent properties such as mechanical properties, heat resistance and fatigue resistance is used as a resin composition of a molded article for a photographic light-sensitive material. The purpose is to be applicable.

[0007]

In order to achieve the above object, the present invention provides a resin composition for a molded article for a photographic light-sensitive material, wherein the formaldehyde concentration generated from the molded article is 20 ppm or less in a sealed container, and A polyacetal resin prepared so as not to impair photographic properties is used. The concentration of formaldehyde gas generated from a molded product of such a polyacetal resin is extremely small, does not reduce the silver halide emulsion to cause chemical fog, and does not affect other harmful chemicals that affect photographic properties. It is suitable for a resin composition used for a molded article for a photographic light-sensitive material because it does not generate a substance.

Furthermore, when adding an antioxidant to the above polyacetal resin in order to prevent thermal denaturation due to oxidation during heating, a hindered phenol-based antioxidant is added in an amount of 0.0
By using it in the range of 01 to 1.0% by weight, it becomes possible to more effectively suppress the generation of formaldehyde. If it is less than 0.001% by weight, the effect of addition is not exhibited, and if it exceeds 1.0% by weight, not only the photographic properties are adversely affected but also the physical properties are deteriorated. In addition, the light-shielding substance is 0.
By adding in the range of 05 to 25% by weight, it is possible to improve the light-shielding function required for a molded product used around a photographic light-sensitive material without impairing the chemical and physical characteristics of the polyacetal resin. . If it is less than 0.05% by weight, the light-shielding property cannot be secured, the purpose of addition cannot be achieved, and the cost increases. If it exceeds 25% by weight, the physical strength is lowered and the appearance is deteriorated.

FIG. 1 schematically shows a film pack molded from the polyacetal resin composition of the present invention. Exposure aperture 2
A box-shaped case 3 formed with a box-shaped case 3 and a bottom lid 5 to which a leaf spring 4 is fixed constitute a pack body, in which a light-shielding sheet 6 is formed.
Then, about 10 mono-sheet type instant film units 7 are stored. The polyacetal resin of the present invention can be used as a molding material for the case 3, the leaf spring 4, the bottom cover 5, and the light-shielding sheet 6. However, appropriate resins among these components can be used as other resins such as polystyrene resin. You may shape.

In addition to the exposure opening 2, the case 3 is provided with a slit-shaped discharge port 8 and a notch 9 into which a scraping claw is inserted. When the bottom cover 5 is fixed to the bottom surface of the case 3,
The leaf spring 4 pushes up the instant film unit 7 and the light shielding sheet 6 housed in the pack body, and the light shielding sheet 6 covers the exposure opening 2 from the inner surface side of the case 3. As a result, the instant film unit 7 in the pack body is
Is kept light tight. The outlet 8 is covered with a flexible light-shielding film.

The instant film unit 7 is provided with a developing solution pod 7a containing a developing solution. After the film pack is loaded into the camera and the light-shielding sheet 6 is ejected, it is possible to take a picture. When photographing is performed, a scraping claw provided in the camera enters through the notch 9 and scrapes out the instant film unit 7 exposed through the exposure opening 2 from the discharge port 8. After that, the developing roller built in the camera rotates the exposed instant film unit 7 coming out from the discharge port 8 while pressing it from above and below, and crushes the developer pod 7a to discharge it.

The leaf spring 4 presses the uppermost one of the instant film units 7 housed in the pack body against the inner surface of the exposure opening 2 to expose the instant film unit 7 used for the next photographing. It acts to position it. Therefore, particularly when the leaf spring 4 is made of a resin molded product, it is necessary to mold the resin with a resin having sufficient elasticity and not losing its elasticity even when left for a long time.

The resin composition of the present invention has the characteristics that, even when used as a molding material for the leaf spring 4 as described above, it has the elasticity required for it and almost no creep deformation occurs. The resin composition of the present invention uses a polyacetal resin as a monomer, and the polyacetal resin used here is a polyacetal resin that has been commonly used until now, and is an aldehyde, for example, a cyclic oligomer of formaldehyde and formaldehyde. Polymers obtained by polymerizing or copolymerizing trioxane, tetraoxane or the like, or polymers obtained by copolymerizing these aldehydes and cyclic ethers or cyclic acetals such as ethylene oxide, probion oxide and 1,3-dioxolane. .

The main chain of this polyacetal resin is "-
(CH ₂ O) _n - "units (n is a natural number) and / or" -
(CHR-O) _n - "units (R is alkyl: n is a natural number) a, or terminal groups is not protected, or" -OCOCH ₃ "," - OCH ₃ "," - OCH ₂ -
It is a linear polymer protected by a group such as "OH" and has a number average molecular weight of 10,000 to 100,000, preferably 1.
It is 8,000 to 70,000.

In order to reduce the concentration of formaldehyde gas released from the polyacetal resin, 0.05 to 3.0 parts by weight of the organic cyclic compound having an active imino group represented by the general formula (I) is added to 100 parts by weight of the polyacetal resin. It is preferable to add 0.06 to 2.0% by weight, and particularly preferably 0.067 to 1.0% by weight. Here, R ¹ , R ² and R ³ in the general formula (I) represent divalent organic radicals, each of which represents a cyclic organic compound formed by a covalent bond.

[0016]

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The active imino compound has a highly reactive imino group, and reacts with formaldehyde as shown in the following reaction formula (II) in the process in which the polyacetal resin crystallizes and solidifies and after solidification. Compounds capable of forming are desirable.

[0018]

Embedded image

In order for the imino group to have this reactivity, the electron concentration of the imino group must be low enough to cause an electron nucleophilic reaction. For that purpose, an organic radical directly chemically bonded to the imino group is required. Must be electron-withdrawing. Such an organic radical, that is, an organic radical represented by R ¹ , R ² , and R ³ in the above general formula (I) has “—CO—” at a position bonded to an imino group,
"-COO -", "- NH -", "- NH _2", a phenyl group, a biphenyl group, a compound having a naphthalene group and the like.

Further, when a compound is added to the polyacetal resin, it is essential that the compound does not migrate by melt mixing or cause thermal decomposition. From the above, examples of the compound represented by the general formula (I) include hydantoins, imidazole compounds, and the like, but in the present invention, hydantoins are preferable. Examples of the hydantoin compound include hydantoin, 5,5-dimethylhydantoin, 5,5-diphenylhydantoin, allantoin, and the like.
It is not necessarily limited to these.

Further, the acetal resin composition used in the present invention needs a lubricant, a light-shielding substance, an antioxidant, a heat stabilizer, and further an appropriate plasticizer or filler within a range not impairing the effects of the present invention. Can be added accordingly.

Typical lubricant names and manufacturer names that can be used in the acetal resin composition of the present invention are listed below. (1) Silicone-based lubricant Various grades of dimethylpolysiloxane and its modified products (Shin-Etsu Silicone, Toray Silicone) (2) Oleic acid amide lubricant Armoslip CP (Lion Akzo), Neutron (Nippon Seika), Neutron E -18 (Nippon Seika),
Amide O (Nitto Kagaku), Alfro E: 10 (Nippon Yushi), Diamid O-200 (Nippon Kasei), Diamid C-200 (Nippon Kasei), etc.

(3) Elucic acid amide lubricant Alfro-F-10 (NOF Corporation), etc. (4) Stearic acid amide lubricant Alflo-S-10 (NOF CORPORATION), Neutron 2 (NIPPON SEISAKU), DIA Mid 200 (Nippon Kasei) etc. (5) Bis fatty acid amide lubricant bisamide (Nippon Kasei), Diamid 200 bis (Nippon Kasei), Armowax BBS (Lion Akzo), etc. (6) Nonionic surfactant lubricant Electrostripper TS-2, Electro Stripper-TS-3 (Kao Soap), etc.

(7) Hydrocarbon lubricant Liquid paraffin, natural paraffin, micro wax,
Synthetic paraffin, polyethylene wax, polypropylene wax, chlorinated hydrocarbon, fluorocarbon (8) Fatty acid type lubricant Higher fatty acid (C ₁₂ or more is preferable), Oxy fatty acid (9) Ester type lubricant Lower alcohol ester of fatty acid, polyhydric alcohol of fatty acid Esters, polyglycol esters of fatty acids, fatty alcohol esters of fatty acids

(10) Alcohol-based lubricant Polyhydric alcohol, polyglycol, polyglycerol (11) Metal soap Higher fatty acid such as lauric acid, stearic acid, ricinoleic acid, naphthenic acid and oleic acid, and Li, Mg, Ca, S
Compounds with metals such as r, Ba, Zn, Cd, Al, Sn and Pb

Further, examples of the light-shielding substance added to secure the light-shielding property include the following. (1) Inorganic compound A. Oxide Silica, diatomaceous earth, alumina, titanium oxide, iron oxide, zinc oxide, magnesium oxide, antimony oxide, barium ferrite, strontium ferrite, beryllium oxide, pumice, pumice balloon, alumina fiber, etc. B. Carbonate calcium carbonate, magnesium carbonate, dolomite, dawsonite, etc.

C. Silicate talc, clay, mica, asbestos, glass fiber, glass balloon, glass beads, calcium silicate, montmorillonite, bentonite, etc. D. Carbon Carbon black, graphite, carbon fiber, carbon hollow sphere, etc. E. Other iron powder, copper powder, lead powder, tin powder, stainless powder, pearl pigment,
Aluminum powder, molybdenum sulfide, boron fiber, silicon carbide fiber, brass fiber, potassium titanate, lead zirconate titanate, zinc borate, barium metaborate, calcium borate, sodium borate, aluminum paste,
Talc etc.

(2) Organic compound Wood powder (pine, oak, sawdust, etc.), cereal fiber (almond,
Peanuts, fir shells, etc.), various colored fibers such as cotton, jute, paper strips, cellophane strips, nylon fibers, polypropylene fibers, starch, aromatic polyamide fibers, etc.

Among these light-shielding substances, carbon black is preferable because it can reduce the amount of bleed-out. Examples of particularly preferable carbon black raw material classifications include gas black, furnace black, channel black, anthracene black, acetylene black, Ketjen carbon black, lamp black, oil smoke, pine smoke, animal black, and vegetable black.

In the present invention, furnace carbon black is preferable for the purpose of improving the light-shielding property, cost and physical properties, and acetylene carbon black and Ketjen carbon black which is a modified synthetic carbon black are expensive as the light-shielding substance having an antistatic effect. Is preferred. If necessary, it is also preferable to mix the former and the latter according to the required characteristics.

There are various forms of blending the light-shielding substance,
The masterbatch method is preferable from the viewpoints of cost and prevention of contamination of the workplace. Japanese Patent Publication No. 40-19696 discloses a method of dispersing a carbon black in a solution of a polymer dissolved in an organic solvent to prepare a polymer-carbon black masterbatch, and Japanese Patent Publication No. 43-10362. A method of dispersing carbon black in polyethylene to make a masterbatch is described.

When used as a molded product for a photographic light-sensitive material of the present invention, no fog is generated on the photographic light-sensitive material,
The increase or decrease in the photosensitivity is small, the light-shielding ability is large, and even when added to the resin composition of the present invention, it is difficult to generate lumps of carbon black and pinholes due to fish eyes. PH in black
A furnace carbon black having an average particle diameter of 6.0 to 9.0 and an average particle diameter of 10 to 120 mμ is preferable, and of these, a furnace carbon black having a volatile component of 2.0% or less and an oil absorption of 50 ml / 100 g or more is preferable. Since channel carbon black is expensive, it often causes fog on the photographic light-sensitive material, which is not preferable. Even if it is absolutely necessary to use it, its influence on photographic properties should be investigated and selected.

A commercially available product of carbon black is, for example, carbon black # 20 manufactured by Mitsubishi Kasei.
(B), # 30 (B), # 33 (B), # 40 (B),
# 44 (B), # 45 (B), # 50, # 55, # 10
0, # 600, # 2200 (B), # 2400 (B),
MA8, MA11, MA100 and the like can be mentioned.

As overseas products, for example, Black Pearls 2, 46, 70, 71, 74, 80 manufactured by Cabot Corporation,
81, 607, etc., Regal 300, 330, 400, 66
0, 991, SRF-S, etc., Vulcan 3, 6, etc., Sterli
ng 10, SO, V, S, FT-FF, MT-FF and the like. In addition, United of Ashland Chemical
R, BB, 15, 102, 3001, 3004, 30
06, 3007, 3008, 3009, 3011, 30
12, XC-3016, XC-3017, 3020, but not limited thereto.

The amount of the light-shielding substance added is 0.05 to 25% by weight, preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight, and most preferably 1.0 to 7.0. It is in the range of% by weight.

Further, it is preferable to add an antioxidant in order to prevent thermal deterioration of the resin and to prevent fish eyes and lumps (lump-like non-uniform failure) from occurring. Representative examples of the most preferred hindered phenolic antioxidants for the present invention are shown below.

1,3,5-trimethyl 2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tetrakis [methylene-3- (3 '.
5'-di-tert-butyl-4'-hydroxyphenyl)
Probionate] Methane, octadecyl-3,5-di-
tert-butyl-4-hydroxy-hydrocinnamate,
2,2 ', 2'-Tris [(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] ethyl isocyanurate, 1,3,5-Tris (4-tert-
Butyl-3-hydroxy-2,6-di-methylbenzyl] isocyanurate, tetrakis (2,4-di-tert.
-Butylphenyl) 4,4'-biphenylenediphosphite,

4,4 ': thiobis- (6-tert-butyl-O-cresol), 2-2'thiobis (6-tert-butyl-4-methylphenol), tris- (2-methyl-4-hydroxy) -5-tert-butylphenyl) butane, 2,2'-methylene-bis- (4-methyl-6-te
rt-butylphenol), 4,4'-methylene-bis-
(2,6-di-tert-butylphenol), 4,4'-
Butylidene-bis- (3-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-methylphenol, 4-hydroxymethyl-2,6-di-tert
-Butylphenol, 2,6-di-tert-4-n-butylphenol,

2,6-bis (2'-hydroxy-3 '
-Tert-butyl-5'-methylbenzyl) -4-methylphenol, 4,4'-methylene-bis- (6-tert-
Butyl-O-cresol, 4,4'-butylidene-bis (6-tert-butyl-m-cresol), 3.9-bis {1.1-dimethyl-2- [β- (3-t-butyl- Four
-Hydroxy-5-methylphenyl) propionyloxy] ethyl} 2,4,8,10-tetraoxaspiro [5,5] undecane and the like. Among these, those having a melting point of 100 ° C. or higher, particularly 120 ° C. or higher are preferable. The amount of the hindered phenolic antioxidant added is 0.001 to 1.0% by weight, preferably 0.00
The range is 5 to 0.8% by weight, more preferably 0.01 to 0.6% by weight, and most preferably 0.02 to 0.4% by weight.

Further, as the heat stabilizer added to the resin composition of the present invention, a polyamide compound, particularly a nylon terpolymer, US Pat. Nos. 4,776,168 and 4,814 are used.
There are hydroxy-containing polymers such as those described in 397, and also non-melting nitrogen-containing or hydroxy-containing polymers such as those described in EP 0388809,
More specifically, polyamide 6, polyamide 6/12 copolymer, polyamide 6/66/610 terpolymer,
Polyamide 6/66/612 terpolymers, ethylene / vinyl alcohol copolymers, acrylamide (co) polymers, acrylamide / N, N-methylenebisacrylamide copolymers, and the like. Generally, the total amount of heat stabilizers added to the polyacetal resin composition is the acetal resin 1
It is 0.05 to 5.0 parts by weight, preferably 0.05 to 1.50 parts by weight with respect to 00 parts by weight.

A molded article composed of such a polyacetal resin composition can be molded by any method including compression molding, injection molding, extrusion molding, blow molding, rotational molding, melt spinning and thermoforming. In particular, injection molding is preferable in order to obtain a molded product according to the present invention.

[0042]

EXAMPLES Hereinafter, specific examples of the present invention will be described together with comparative examples, but the present invention is not limited to the examples given here.

The polyacetal resins used in the following examples are Delrin 900 PNC10 (trade name: melt index 11.5 g / min) and Delrin 1700 PNC10 (trade name: melt), which are high flow standard grades of polyacetal homopolymer manufactured by DuPont. Index 1
It was 8.0 g / min), and the following were prepared as additives used for the purpose of preventing oxidation at the time of heating the resin and reducing formaldehyde gas.

Additive 1: Hydantoin (manufactured by Mitsui Toatsu Chemicals, Inc.) Additive 2: 5,5-Dimethylhydantoin (manufactured by Mitsui Toatsu Chemicals, Inc.) Additive 3: Dihydrazide adipic acid (manufactured by Nippon Hydrazine Industry Co., Ltd.) ) Additive 4: stearic acid monoglyceride (manufactured by Riken Vitamin Co., Ltd.)

Example A Delrin 900 PNC10 (5000 g) simple substance, 25 g of one of the above additives 1 to 4 was further added to Delrin 900 PNC10 (5000 g) simple substance, melt-kneaded with a 35 mm twin-screw extruder and cut into pellets. 5 kinds of resin materials in the shape of a circle were obtained. The resin temperature at this time is 195
The feed rate was about 30 kg / hr at ˜198 ° C. Five types of test pieces A-1 to A5 each having a cylindrical shape were molded by a 75-ton Sumitomo Nestal injection molding machine using the obtained resin pellets. The resin temperature and the mold temperature in the molding were 250 ° C and 75 ° C, respectively.

Test pieces A-1 to A thus prepared
Five pieces of each -5 (total weight of about 75 g) were placed in a polyethylene container having a capacity of 1 liter and sealed. Then, after leaving it in the room for 24 hours, the formaldehyde concentration in the container was measured to a ppm level using a formal meter Meter II (Lion, UK). The results of this measurement are shown in Table 1.

[0047]

[Table 1]

As is clear from Table 1, any of the additives has an effect of reducing the formaldehyde concentration in the molded article, and of these, the additive 2 is particularly effective. Although the effect of the fatty acid ester-based additive 4 is recognized, it is found that it is insufficient. In addition, additive 3
The formaldehyde concentration can be suppressed to 15 ppm or less even with the use of, but with this, hydrazine is gradually released and exerts a reducing action on the photographic light-sensitive material, which adversely affects the photographic property and also affects the human body. It becomes harmful. Considering these points, the degree of influence of hydrazide contained in each test piece is shown in the hydrazide evaluation column of Table 1. Further, the degree of fog of the photographic light-sensitive material is shown in the fog evaluation column based on the formaldehyde concentration. In the marks attached to these evaluation columns, ◯ means no problem in practical use, ● means practical limit, ▲ means improvement required, and × means impractical.

Example B 200 g of the above-mentioned additive 2 was added to Delrin 900 PNC10 (9,800 g), melt-kneaded with a 35 mm twin-screw extruder (Toshiba TEM35), and cut into pellets of the additive 2. A concentrate (masterbatch) was created. The resin temperature at this time is about 200 °
C, the feed rate was 25 kg / hr. The concentrate of the obtained additive 2 is referred to as additive A.

Additive A was used as a highly fluid Delrin D1700PN
C10 pellets were mixed at different ratios, and cylindrical test pieces B-1 to B-7 were molded in the same manner as in Example A. The test piece B-1 is a sample containing no additive A. The formaldehyde concentrations of these test pieces B-1 to B-7 were measured under the same conditions as in Example A. The measurement results are shown in Table 2.

[0051]

[Table 2]

As is apparent from Table 2, in order to reduce the formaldehyde concentration in the molded product to the extent that fog does not occur in the photographic light-sensitive material, it is sufficient to add the additive 2 in an amount of 0.05% by weight or more. I understood. However, if the concentration of the hydrazide contained in the additive 2 is too high, it acts as a reducing agent on the photographic light-sensitive material and also has an adverse effect on the human body.
The amount is preferably 3.0% by weight, preferably 0.06 to 2.0% by weight, and particularly preferably 0.067 to 1.0% by weight. When the concentration of the additive 2 exceeds 0.5% by weight, the elastic modulus of the molded product is considerably lowered, so that there is a problem when the molded product molded from this resin is used as a spring material.

Example C Next, using the resin having the same composition as the test pieces B-1 to B-6 of Example B, the leaf spring 4 shown in FIG. 1 was injection molded.
A sample was collected from each of the leaf springs thus obtained so as to weigh 75 g, and the sample was hermetically stored together with the photographic light-sensitive material in a moisture-proof bag (water vapor transmission rate: 0.5 g / m ² · 24 hr).
It was left for 3 days in a dry atmosphere at ° C. FUJICOLOR NC-160 was used as the photographic light-sensitive material.

Then, the photographic light-sensitive material was taken out and developed, and the fog density D _min in the blue color where fog was most likely to occur was measured. The fog density D _min represents the density difference from the standard photographic light-sensitive material which was left alone for 3 days under the same conditions as described above. The measured values are shown in Table 3 and Example B.
A graph showing the correlation with the formaldehyde concentration measured in FIG. 2 is shown in FIG.

[0055]

[Table 3]

According to the graph of FIG. 2, if the addition amount of the additive 2 having a function of trapping formaldehyde is 0.067% by weight or more, the chemical fog density due to formaldehyde is blank test / fog density standard D. _min =
It can be seen that it converges to 0.8 ± 0.2. And, in this range, the concentration of formaldehyde is suppressed to 5 ppm or less,
Since the fog density can be set to 1.0 or less, there is no problem even if it is used around the photographic light-sensitive material.

As described above, it is confirmed that increasing the amount of the additive 2 added has an effect of reducing the formaldehyde concentration, but if the amount is too large, the elasticity of the molded product is impaired. FIG. 3 shows a graph showing the correlation between the addition amount of the additive 2 and the flexural modulus of the molded product. As can be seen from this graph, when the additive 2 is added in an amount of 0.5% by weight or more, the flexural modulus is remarkably lowered, and when the leaf spring 4 shown in FIG. 1 is molded with the polyacetal resin of the present invention, the additive is added. 2 is preferably added in the range of 0.5% by weight or less.

As described above, the additive 2 was added in an amount of 0.05 to 3.
According to the polyacetal resin added in the range of 0% by weight, preferably 0.06 to 2.0% by weight, the residual concentration of formaldehyde can be significantly reduced, and even if it is used together with a photographic light-sensitive material, it causes a problem. To a certain extent, fog does not occur on the photographic light-sensitive material. When the addition amount of the additive 2 is in the range of 0.067 to 1.0% by weight, the bending elasticity of the molded product is hardly reduced, and even if it is used as a spring member, no problem occurs. There is no such thing.

The polyacetal resin of the present invention having such characteristics is used not only for the magazine for storing the photographic light-sensitive material such as the above-mentioned film pack, but also for the production line of the photographic light-sensitive material, the camera, the film and the photographic paper. It can be applied to various molded products such as plate materials, transport rollers and gears used in the periphery.

Further, preferred embodiments included in the present invention are as follows. (1) A resin composition for use in a molded article for a photographic light-sensitive material according to claim 1, comprising a polyacetal resin composition containing at least a polyacetal resin and an organic cyclic compound having an active imino group. (2) The resin composition used in a molded article for a photographic light-sensitive material according to claim 1, which comprises a polyacetal resin composition containing at least a polyacetal resin and a hydantoin compound. (3) A lubricant containing 0.01 to 10% by weight,
Alternatively, the resin composition used in the molded article for a photographic light-sensitive material according to any one of the above embodiments (1) and (2).

[0061]

As described above, in the polyacetal resin of the present invention, the generated formaldehyde concentration is 20 ppm or less in the sealed container so that the photographic property is not impaired. It does not cause chemical fog even if it is used in the surrounding area.
In order to effectively reduce the concentration of formaldehyde generated from the polyacetal resin, a hindered phenol compound can be used as an antioxidant added to the polyacetal resin, and the addition amount thereof is 0.001 to 1.0.
By setting the content in the range of weight%, it becomes possible to prevent fog of the photographic light-sensitive material. Moreover, 0.05-2
It is also possible to add an appropriate light-shielding substance in the range of 5% by weight, and it is possible to reliably prevent the occurrence of optical fog.

Further, since the resin molded article prepared as described above does not cause chemical or optical fog on the photographic light-sensitive material, it can be used in various forms such as magazines, plate materials and rollers. In addition to the above, it is possible to easily mold a material having sufficient elasticity and use it as a spring material.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an instant film pack using the present invention.

FIG. 2 is a graph showing the correlation between formaldehyde concentration and fog concentration.

FIG. 3 is a graph showing the correlation between the amount of 5,5-dimethylhydantoin added and the flexural modulus.

[Explanation of symbols]

 3 Case 4 Leaf spring 5 Bottom lid 7 Instant film unit

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Kenichi Shinohara 4997 Shinyoshida-cho, Kohoku-ku, Yokohama-shi, Kanagawa DuPont Co., Ltd. Central Research Laboratory (72) Inventor Robert J. Cassall Wilmington Market Street, Delaware, USA 1007 within EAI DuPont de Nemours & Company

Claims (4)

[Claims] 1. A photograph characterized by being a polyacetal resin composition, wherein the concentration of formaldehyde generated from a molded article made of the composition is 20 ppm or less in a sealed container and the photographic property is not impaired. A resin composition used for a molded article for a photosensitive material. 2. The resin composition for use in a molded article for a photographic light-sensitive material according to claim 1, which contains 0.001 to 1.0% by weight of a hindered phenolic antioxidant. 3. The resin composition for use in a molded article for a photographic light-sensitive material according to claim 1, which contains a light-shielding substance in an amount of 0.05 to 25% by weight. 4. A molded article for a photographic light-sensitive material, characterized by being molded with the resin composition according to any one of claims 1 to 3.