JPH09258386A - Zeolite molecular sieve for packaging structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the packaging structure capable of improving dryness and absorbing gases by forming at least a part of the packaging vessel with a blend comprising the granular molecular sieve and a polymer. SOLUTION: At least a part of the packaging vessel is formed with the material blended of the granular molecular sieve material and the polymer. Air pollution gases, such as H2 O2 , SO3 , and O3 are catalytically decomposed and the stabilities of nonused and processed films are raised. Even when the molecular sieve is saturated with water, the structure is kept stable and electrically conductive and it protects the structure materials electrostatically, and further, the water content decreases during storage and consequently, the glass transition point of a gelatin emulsion is elevated, thus permitting the storage stability of the nonused photographic film to be improved.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to water vapor absorption or S
The present invention relates to a method and an article for improving the storability of a substance which is deteriorated by absorption of O ₂ or ozone. More particularly, this invention relates to the storage of photographic film.

[0002]

BACKGROUND OF THE INVENTION Processed and unprocessed photographic film
The ability to store without changing the properties of the film
It is important to maintain the exposed and developed film as well as to maintain the unchanged performance of the unexposed film. It is expected that the archivability of photographic film should be measured in decades. The properties of the unexposed film are intended to remain stable upon storage for extended periods of time under a variety of conditions.

It is common practice to use a hermetically sealed container of plastic or metal or to seal in a metal-coated polymeric bag to prevent moisture or moisture approaching the film. It is also desirable to protect the film from gases such as SO ₂ and ozone. Other materials such as food also need to be sealed and protected. This is usually a Modified Atmosphere P
ackaging) (MAP). This is the case when creating specific environmental conditions within the package that differ from typical ambient atmospheric conditions.

Also, US Pat. No. 5,215,215 to Ram et al.
No. 192 discloses the inclusion of particulate material, such as molecular sieve zeolite, in the film storage container for the exposed film to improve the storability of the exposed film. Desiccants for packaging inserts for films or cameras or coatings for packaging are also available at Deffe
Proposed in yes US Pat. No. 4,036,360.

Schroder US Pat. No. 5,18
No. 9,581 it is proposed to put a desiccant in the video camera to dry the camera.

[0006] However, the above system for containing a substance for drying in a package or device has some drawbacks. Disposal of desiccant packs is difficult because the consumer does not know how to handle it. Furthermore,
These can be replaced or destroyed and interfere with the function of the components provided with humidity protection. In addition, these add to the cost due to the separate assembly steps for placing the desiccant pack in the package as well as the cost of manufacturing the desiccant package.

[0007]

There is a need for a method of providing packages and articles with improved drying and gas absorption protection. Further, there is a need for better ways to provide photographic articles and packages with dry protection.

[0008]

The object of the present invention is to overcome the drawbacks of the prior art methods and articles. Another object of the invention is to provide improved moisture protection for photographic articles. An additional objective is to provide improved storage quality and containers for storing photographic materials.

These and other objects of the present invention generally relate to storage quality of a container comprising at least a portion of the structure of the container formed from a material comprising a blend of a particulate molecular sieve material and a polymer. This is accomplished by providing an improved method. Another aspect of the present invention provides
At least a portion of the structure of the container is a container made of a blend of a particulate molecular sieve material and a polymer. A preferred container is a film holder.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention is advantageous in that cameras and cartridges operate under different climatic conditions with less variability because it is formed, at least in part, from the dry materials of the present invention. have. The curls and coresets inherent in film in magazines and cartridges will be reduced. The addition of the molecular sieve of the present invention also produces H ₂ O ₂ , SO
Air pollutants such as ₃ and ozone are catalytically decomposed, which increases the constancy of virgin and treated films. Even when water saturation of the molecular sieve of the present invention occurs, the structural product maintains its constancy and is also electrically conductive, providing electrostatic protection to the material. The present invention also has the advantage that the reduction of moisture during storage improves the virgin film shelf life of photographic films by increasing the glass transition temperature of the gelatin emulsion due to the reduced moisture content. . The present invention also has the advantage that ferrotyping / sticking / blocking of roll film under normal and reverse storage conditions is minimized regardless of the film support material. Stable storage of film will also lead to improved film drive in cameras and cartridges. In addition, by reducing the water content during storage, film degradation is reduced by reducing the hydrolysis of the support which leads to film degradation over long periods of storage, both for virgin films and especially for treated films. Will decrease. These and other advantages will be apparent from the description below.

In the practice of the present invention, the molecular sieve material is then blended with a polymer formed into structural components that find their preferred use in the photographic art. The structural components of the polymer molecular sieve blend can be used in a container. This container contains processed film,
It can be used for exposed but untreated film or unexposed film. The structural polymeric materials of the present invention can also be used in other products that benefit from the absorption of water vapor and air pollutants by molecular sieves. The structural polymeric materials and containers will also find use in packaging electrical materials and dry foods.

In the storage of photographic materials, the gelatin containing the imaging material has various glass transition temperatures depending on the amount of residual moisture due to the relative humidity of the surrounding air at equilibrium as shown in Table I. It is important that the relative humidity be maintained at a low percent water content, as

[0013]

[Table 1]

As shown in the table above, a relative humidity of 80
%, The glass transition temperature is generally room temperature. Even at 70% relative humidity, the glass transition temperature can reach many storage conditions such as in a warehouse. Water absorption by the zeolite will raise the glass transition temperature of gelatin. The resulting increase in glass transition temperature will prevent rapid degradation of the film due to hydrolysis. The reduction of the glass transition temperature by chemicals other than water vapor must be prevented.

The term "film holder" as used in the description of this invention includes materials for storing and holding film material in both developed and undeveloped states. This includes single-use camera parts and multiple-use camera parts. This further includes the use of the material as a core to wind up the unexposed film. This includes forming or exposing containers and parts of containers for storing exposed and unexposed film (ie, 35 mm film cans, large format cartridges, aerial film cans, movie reel cans). Included is the use of the polymer blend material of the present invention as a core for winding and storing the treated film. It is intended to include everything that contains a film.

When the term "structural" or "structural" is used in the description of this invention, this phrase is intended to include the use of polymeric molecular sieve blends as an integral part of film holders or other articles. Is intended to By virtue of the integral member, the polymer and molecular sieve blend is not just an additional member or insert that serves to bring the molecular sieve into the article, but the molecular sieve-containing member functions in the formation of the film holder or other article. It is meant to perform the intended function. For example, the blends of the present invention can form a film core that winds film prior to insertion into a film cartridge, cassette or single-use camera. The film cassette can hold a support that records both magnetic and silver halide imaging media. The core of the present invention is a sheave-containing material, rather than a core having other polymer blends intercalated therein. The structural member may also be the lid of the container or at least part of the container itself. The term "structure" is intended to be distinguished from the encapsulation of the desiccant material in the structural member, which is not an integral part of the member and which serves no structural purpose.

Use of all suitable desiccants for the present invention
can do. Typical of suitable substances are calcium,
Such as cobalt, magnesium & aluminum salts
It is a salt of Group II and Group III metals. A particularly suitable salt is M
gSO_FourIt is. They blend well with the polymer
Has the ability to dry, has good desiccant properties, and SO _Two
Cellulose nitrate that absorbs other gases such as and during storage
Absorbs acids like acetic acid released from the film base
Therefore, the preferred material is molecular sieve zeolite.
It is.

For example, type A, type L, type X,
All suitable molecular sieve zeolites such as type Y and mixtures of these zeolites can be used in the present invention. The molecular sieve material is a crystalline hydrated metal aluminosilicate which is a synthetically produced or naturally occurring mineral. Such materials are disclosed in U.S. Pat. Nos. 2,882,243 and 2,882,24.
No. 4, No. 3,078,636, No. 3,140,2
35 and 4,094,652, all of which are incorporated herein by reference. In the practice of the present invention, two types, type A and type X, are preferred. Molecular sieve zeolites contain interconnected uniform sized cavities separated by narrower openings or pores of equal uniformity within each crystal. When formed, the crystalline network is filled with water, but upon gentle heating, water can be released from the cavities without changing the crystal structure. This leaves a cavity with its combined surface area and pore volume available for absorbing water or other substances. The process of emptying and refilling the cavity can be repeated indefinitely under advantageous conditions.

The molecular sieve allows for fine process control because the pores of the crystalline network are uniform rather than of varying size as with other adsorbents. With a large surface area and pore size, molecular sieves can utilize the homogeneity of the pores to separate molecules and distinguish on the basis of molecular size and configuration.

The molecular sieve is a crystalline metal aluminosilicate having a three-dimensional network structure of silica and alumina tetrahedra. This very uniform crystal structure gives the molecular sieve the property of making it an excellent desiccant in high volumes at high temperatures. This tetrahedron is formed by four oxygen atoms surrounding silicon or aluminum atoms. Each oxygen atom has two negative charges and each silicon has four positive charges. This structure allows for distributive placement, forming tetrahedra uniformly in four directions. The trivalency of aluminum negatively charges the alumina tetrahedron and requires additional cations to equilibrate the system. Therefore,
The final structure has sodium, potassium, calcium or other cations within the network. These charge balancing cations are exchangeable ions of zeolite structure.

In the crystalline structure, less than half of the tetravalent silicon atoms can be replaced by trivalent aluminum atoms. Zeolites containing different ratios of silicon ions to aluminum ions are available, as are different crystal structures containing various cations. In Type A, the most common commercially available zeolite, the tetrahedra are grouped to form truncated octahedra with silica or alumina tetrahedra at each point. This structure is known as a sodalite cage.

When the sodalite cages are stacked in a simple cube shape, the result is a mesh of cavities of about 11.5Å in size that are accessible through openings on all six sides. These openings are surrounded by eight oxygen ions. One or more exchangeable cations also partially block the face area. In the sodium form, this ring of oxygen ions provides a 4.2 Å diameter opening into the structure. This crystal structure is chemically represented by the formula: Na ₁₂ [(AlO ₂ ) ₁₂ (SiO ₂ ) ₁₂ ] XH ₂ O. The water of hydration that fills the cavities during crystallization is loosely bound and can be removed by mild heating. The pores previously occupied by this water can be refilled by absorbing various gases or liquids. The number of water molecules in the structure (value of X) can be increased as 27.

The sodium ions attached to the aluminum tetrahedra may tend to block the openings or, conversely, may aid in the passage of molecules slightly oversized by their charge. As a result, this sodium forms a molecular sieve, commercially referred to as 4A, which can be considered to have a uniform opening of approximately 4Å diameter. Due to its basic exchange properties, zeolites can be easily prepared by replacing the sodium part with other metals.

Of the synthetic zeolites, two modifications have been found to be particularly useful in industry. By replacing most of the sodium with potassium ions, (about 3Å
3A molecular sieves (with openings of 3) are formed. Similarly, when using calcium ions for exchange, 5A (with an opening of about 5Å) is formed. The crystal structure of Type X zeolite is formed by placing a basic sodalite cage in a tetrahedral volume stack (diamond structure) with a bridge across a 6-membered oxygen atomic ring. These rings have a diameter of 9-10Å inside the structure.
Make an opening. The overall charge is balanced by the positively charged cation (s), as in the Type A structure. The chemical formula representing the unit cell of the type X molecular sieve in the soda form is shown below. As in the case of Na ₈₆ [(AlO ₂ ) ₈₆ (SiO ₂ ) ₁₀₆ ] XH ₂ O type A crystals, the water of hydration is removed by gentle heating and the pores thus created are separated by other liquids. Or it can be refilled with gas. The value of X can be as large as 276.

The basic requirement for all adsorbents is to have a large surface area per unit volume.
Furthermore, this surface is chemically inert and must be available for essential adsorbates. From a purely theoretical point of view, the rate at which the molecules are adsorbed depends on the rate at which the molecules come into contact with the surface of the adsorbent particles and the rate at which the molecules diffuse into the particles after contact, with all other factors being equal. One or the other of these factors can be controlled under all given circumstances. In either case, one way to accelerate mass transfer is to reduce the size of the adsorbent particles.

Although the synthetic crystals of zeolites are relatively small, eg 0.1 μm to 10 μm, these small particles can bind or agglomerate into larger shapes. Typical commercially available spherical particles are from 1000 μm to 500 μm.
It has an average bound particle size of 0 μm (4-12 mesh). Pellets (1-3 mm diameter), Raschig rings,
Other molecular sheep shapes such as saddles and the like are also useful. Molecular sieves must be used as received from the manufacturer in the driest conditions. If the molecular sieve is exposed to the atmosphere,
It is preferred to reactivate it according to the manufacturer's recommendations.

The molecular sieve is generally incorporated into the polymer by blending it with the polymer prior to forming it into an article. The polymer used is
It may be a thermoplastic semi-crystalline polyolefin polymer such as polyethylene polymer or polypropylene, an amorphous polymer such as polystyrene, butadiene styrene or polyphenylene ether or any thermosetting polymer. Polyester and acrylic resins are also suitable. High impact polystyrene is preferred for forming wound film cartridges. When blended with the polymer that forms the camera component, the resin is typically high impact polystyrene. High impact polystyrene (HIPS) is generally 5-12 wt%
The rubber content is modified with rubber. Containers for film cartridges are typically high density polyethylene or low density polyethylene.

Molecular sieve zeolites are generally in powder form when included in a polymer. However, although the molecular sieves may be somewhat larger than the powders, such as pellets, materials containing larger particles of the molecular sieve material are not strong and are not suitable for more demanding structural applications. .
The blend of polymer and zeolite can be recycled in the same way as pure polymer film holder parts.

The molecular sieve material may be included in any suitable amount. Generally, the average diameter is 0.1
When using molecular sieve zeolites with a particle size of -10 μm, this material may be present in any effective amount up to about 30% by weight of the blend of polymer and zeolite, and most photographic packaging and structures. Still provide suitable structural properties for use in dynamic camera components.
A suitable amount of molecular sieve material is from 2 to 40% by weight of the total weight of the blend of polymer and molecular sieve.
It is. This amount can be varied depending on the mechanical requirements of the structural member. Preferred inclusions for retention of the properties of high density polyethylene and high impact polystyrene used in the formation of photographic articles such as film winding cores, cameras and storage vessels, as well as good absorption of water vapor and other vapors. The amount is about 2-15% by weight of powder.

The method of forming the article can be by any compounding method. Typical polymer forming compounding methods can be used such as a two roll mixer, a line static mixer followed by a high intensity vane mixer and a single screw extrusion. Preferred for this method are:
It has been found to be a twin screw extruder. It is also possible to include a moisture indicator with the extrusion and mixing method. Such materials include anhydrous cobalt (II) salts. The forming method includes web formation. Injection molding is preferred for film holder parts.

Cartridges, containers and camera components that are at least partially formed from the molecular sieves of the present invention must be stored and stored dry until used. In general, when the material is used to form a container for storage of a film or camera component, especially a core for winding the film after loading a single-use camera or placing the film in a container, the packaging Seal the package so that there is no moisture until it is opened for use. Thus, the molecular sieve will be very effective in maintaining the absorption of all water vapor that it does with typical barrier seals for film packaging and storage. However, from high moisture exposure prior to loading the article with film, plastic molded cores, cartridges,
Precautions are needed to protect small cans containing zeolites or all other desiccants.

Above, we have described the use of molecular sieve polymer blend materials primarily for storing films, but this has been found in other areas, especially for drying and toxic gas protection for modified atmospheric packaging materials where it is in transit. They have also found use in packaging to give. The method and construction material can be used for the transportation of electrical components, pharmaceuticals or foods where high moisture conditions are undesirable. The invention also finds use in packaging for optical disks and audio tapes. Cores for audio tapes or optical disks can also be formed from the structural materials of the present invention. Packaging and storage containers for other information recording media, such as information recording discs, can also be formed from the structural members of the present invention. Magnetic and photographic media are subject to the field caused by the presence of nitrous gases and water vapor in the atmosphere to which they are exposed.
All of these would benefit from proximity to structural members such as those formed by the present invention. The inserts of the present invention have been described for use with photographic products. However, this insert has advantages in its ability to absorb water vapor and harmful gases, food, electronic products,
It has found applications in other packaging areas such as magnetic recording media, optical disks and pharmaceutical products.

[0033]

EXAMPLES The present invention will be further described with reference to the following examples, but it goes without saying that the scope of the present invention is not limited to these examples. Parts and percentages are by weight unless otherwise indicated.

Example Molecular sieve type A zeolite is UOP-Molecu
Obtained from lar Sieve Division, Inc. This zeolite has a chemical composition of sodium aluminosilicate and is about 5
It has an average particle size of microns. The molecular sieve was compounded into high impact polystyrene (HIPS) and high density polyethylene copolymer (HDPE) using a 0.812 counter-rotating twin screw compounding extruder. Two batches were formed: Batch A, a 20 percent sheave content masterbatch in HIPS and a 30 percent sheave content masterbatch in HDPE. This material was then unloaded with unblended HIPS and HDPE and molded into ASTM specimens. ASTM this test piece
Tested according to Method D638. The test results are listed in Table II.

[0035]

[Table 2]

[0036]

[Table 3]

In Table III, it is clear that the polymer blend has suitable properties for the structural elements of photographic materials. The formulation of the material was further tested to confirm that the molecular sieve properties of this material were present after blending with the HIPS and HDPE polymers. This polymeric zeolite blend maintains a substantial proportion of zeolite absorption capacity.

It can be seen that the molecular sieve retains most of its absorptive capacity after being formed into a polyethylene container such as those used for storage of film cartridges. Although the present invention has been described in detail with particular reference to its preferred embodiments, it will be understood that variations and modifications thereof can be practiced within the spirit and scope of the invention.

[0039]

The present invention provides a package that provides moisture protection without the need for a separate package of desiccant which presents disposal and packaging problems. The methods and articles of the present invention further provide a monolithic structure that is a structural part of the article and provides dry protection. The methods and articles of the present invention are inexpensive and provide improved film properties by allowing the material to be stored without degradation.

Various aspects of the present invention will be summarized below. Aspect 1: A method for improving the storage quality of a container, wherein at least a part of the structure of the container is formed of a material composed of a blend of a particulate molecular sieve substance and a polymer. Aspect 2: The method according to Aspect 1, wherein the container comprises a film holder. Aspect 3: The process according to aspect 1, wherein the blend consists of about 2-40% by weight of the molecular sieve material. Aspect 4: The method according to Aspect 2, wherein the holder comprises a film cartridge or a film cassette. Aspect 5: The method according to Aspect 2, wherein the holder comprises a single-use camera. Aspect 6: The molecular sieve comprises from about 2 to about 2 of the blend.
A method according to embodiment 1 which constitutes 15% by weight. Aspect 7: A container wherein at least a portion of the structure of the container comprises a blend of polymer and particulate molecular sieve material. Aspect 8: The container according to Aspect 7, wherein the container is a film holder. Aspect 9: The container according to aspect 8, wherein the film holder comprises a film cartridge and the core of the cartridge comprises the blend. Aspect 10: Aspect 8 wherein the holder is a single-use camera
A container according to claim 1. Aspect 11: The container according to aspect 8, wherein at least a part of the structure of the holder comprises at least a part of a small can for storing a film. Aspect 12: The method of aspect 7, wherein the blend consists of about 2-40% by weight of the particulate molecular sieve material. Aspect 13: A method of improving the storage quality of a film holder, which comprises providing a film holder, wherein at least part of the structure of the holder comprises a polymer and particles of salts of calcium, magnesium or aluminum. Aspect 14: Aspect 13 wherein the holder comprises a film cartridge or film cassette and the structure comprises a core
The method described in. Aspect 15: Aspect 1 in which the holder is a single-use camera
3. The method according to 3. Aspect 16: The method according to aspect 13, wherein the salt comprises magnesium sulfate. Aspect 17: A container wherein at least a portion of the structure of the container comprises a blend of a polymer and particles of at least one salt of magnesium, calcium or aluminum. Aspect 18: Aspect 17 wherein the container comprises a film holder
A container according to claim 1. Aspect 19: The film holder according to aspect 18, wherein at least a part of the structure of the holder comprises a core for holding a film in a film cartridge. Aspect 20: A film holder according to aspect 19, wherein the structure of the poulder comprises a small can for storing the film.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication G03C 3/00 580 G03C 3/00 580A B01J 20/18 B01J 20/18 B B65D 81/26 B65D 81 / 26 L C08K 3/34 KAH C08K 3/34 KAH C08L 23/04 LCH C08L 23/04 LCH 51/04 LKY 51/04 LKY

Claims (2)

[Claims] 1. A method of improving the storage quality of a container, which comprises forming at least a portion of the structure of the container from a material comprising a blend of a particulate molecular sieve material and a polymer. 2. A container wherein at least a portion of the structure of the container comprises a blend of a polymer and a particulate molecular sieve material.