JPH055102B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a peel-apart type instant film unit, and more particularly to an instant film unit whose screen frame has good writability.

[Prior art]

A peel-apart type instant film unit (hereinafter simply referred to as a film unit) is a film unit in which a photosensitive sheet on which a negative image is recorded is superimposed on a photosensitive sheet, as described in detail in, for example, Japanese Patent Publication No. 44-2528. It mainly consists of an image-receiving sheet, which is reversed into a negative image and transferred to the image-receiving sheet when the image is transferred to the image-receiving sheet. The photosensitive sheet is bonded to a drawer sheet, and the image receiving sheet is bonded to a mask. The leading end of this mask is joined to the drawer sheet.

After the photosensitive sheet is exposed, when the film unit is pulled out from the film pack, the photosensitive sheet and image receiving sheet pass between developing rollers in an overlapping state. When passing through this developing roller, the developer pot attached to the drawer sheet splits and a jelly-like developing solution (hereinafter referred to as developer)
flows out between the photosensitive sheet and the image-receiving sheet. This flowing developer is spread to a predetermined thickness by a spreading roller, and the negative image recorded on the photosensitive sheet is transferred to the image receiving sheet as a positive image. When the photosensitive sheet and the image-receiving sheet are peeled off after a standard peeling time (standard development time), a photographic image can be obtained on the image-receiving sheet.

The mask is composed of a mask material and a weak sealing layer. Kraft paper, glassine paper, or the like is used as the mask material, and a weak sealing layer is formed on the lower surface of the masking material, and the masking material and the image-receiving sheet are heat-sealed via this weak sealing layer. Examples of conventional weak sealing layers include, for example, U.S. Pat.
As disclosed in No. 1, there is a known method comprising a release layer coated on the lower surface of a mask material and an adhesive layer coated thereon. In US Pat. No. 2,563,387, the release layer is made of zein, a vegetable protein, mixed with triethylene glycol as a plasticizer, and the adhesive layer is made of ethyl cellulose mixed with diethyl phthalate as a plasticizer. It is used. Also, in the above-mentioned US Patent No. 2659673 and US Patent No. 2678274,
Polyvinyl alcohol is used as the release layer,
The adhesive layer is made of ethyl cellulose mixed with diethyl phthalate or triphenyl phosphate as a plasticizer.

In the conventional weak sealing layer, the adhesive strength between the mask material and the release layer and between the adhesive layer and the image-receiving sheet is stronger than that between the release layer and the adhesive layer, so when the image-receiving sheet is peeled off from the mask. It is planned that peeling will occur between the release layer and the adhesive layer, and the adhesive layer will be transferred to the image-receiving sheet and remain as a white screen frame.

However, with conventional weak sealing layers, if the image-receiving sheet is peeled off from the mask after a little longer than the standard peeling time (for example, 30 seconds for monochrome types), the adhesive layer may not be partially transferred to the image-receiving sheet.
Alternatively, a part of the release layer often peels off from the mask material and is transferred to the image-receiving sheet together with the adhesive layer, which causes problems such as an unsightly appearance. As a result of researching this problem, we found that the developer permeates through the mask material and release layer during development.
It was found that the cause was that it reached the adhesive layer and caused the weak sealing layer to swell. It was also confirmed that the degree of swelling of the release layer and adhesive layer increases as the peeling time (development time) increases.

[Purpose of the invention]

The present invention enables stable peeling between the release layer and the adhesive layer even after the standard peeling time has elapsed, and transfers the adhesive layer entirely to the screen frame to improve the appearance. It is an object of the present invention to provide a film unit which provides a clear screen frame and provides good writing performance on the screen frame.

[Features of the invention]

In order to achieve the above object, the present invention provides a processing liquid resistant layer having alkali resistance between the mask material and the weak sealing layer, so that the developer that has permeated the masking material is further transferred to the weak sealing layer. It is characterized in that it does not penetrate.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

[Structure of the invention]

The third part showing the film unit embodying the present invention.
In the figure, a photosensitive sheet 1 has a drawer sheet 2 joined to its front end, and a short skirt 3 for catching excess developer to its rear end. The drawer sheet 2 and skirt 3 are printed in black to eliminate surface reflections.
Furthermore, a developer pot 4 containing a developer is placed next to the photosensitive sheet 1 on the rear end side of the drawer sheet 2;
A funnel 5 is attached to guide the developer towards the photosensitive sheet 1, and a joint 6a of a tab 6 is joined to the tip end thereof.

The image receiving sheet 7 is for recording a final photographic image, and is bonded to the mask 8 via a weak sealing layer, which will be described later. This mask 8 is formed with an opening 8a corresponding to the screen size, and its tip is joined to the drawer sheet 2. Band-shaped rails 9 and 10 made of relatively thick paper are adhered to both sides of this opening 8a. At the rear ends of these rails 9, 10, two plate-like protrusions 1 are provided in order to secure a space for accommodating excess developer.
1 and 12 are glued together.

FIG. 4 shows the unfolded state of the film unit. As is well known, a plurality of the above-mentioned film units are housed in a film pack. This film pack has a spring-loaded film pressure plate housed therein, the photosensitive sheets of a plurality of film units are placed on top of the film pressure plate in an overlapping state, and a plurality of image receiving sheets are placed on top of the film pressure plate. They are located below the film pressure plate in an overlapping state.

When the tab 6 is pulled out by hand after the photosensitive sheet 1 is exposed, the pull-out sheet 2 is pulled out together with the tab 6. At this time, the mask 8 moves toward the exit of the film pack while gradually overlapping the pull-out sheet 2 from its leading end, and the photosensitive sheet 1 gradually goes behind the film pressure plate and is reversed. A pair of developing rollers 15 and 16 are arranged near the exit of the film pack, and the tab 6 passes over the developing roller 15, and the leading edge of the pull-out sheet 2 is slightly pushed out from between the developing rollers 15 and 16. At this time, the joint portion 6a at the rear end of the tab 6 is peeled off from the drawer sheet 2 by the unfolding roller 15.

Next, when the leading edge of the pull-out sheet 2 is grasped by hand and pulled out, the pull-out sheet 2 and the mask 8 first pass between the developing rollers 15 and 16 in an overlapping state, and then the photosensitive sheet 1 and the image-receiving sheet 7 It passes between the developing rollers 15 and 16 in an overlapping state. The drawer sheet 2 is spread out by the development rollers 15 and 16
When passing through the funnel 5, the developer pot 4 attached thereto is crushed, and the developer flows out through the funnel 5 to the rear. This flowing developer is
It is unfolded by the unfolding rollers 15 and 16, and the rail 9,
The thickness is uniform between the photosensitive sheet 1 and the image-receiving sheet 7 which face each other through the substrate 10, and the excess developer is removed by the skirt 3, the mask 8, and the pair of plate-like protrusions 1.
The surplus developer is stored in a surplus developer storage chamber surrounded by 1 and 12, and gradually hardens.

FIG. 1 shows the joint between the image receiving sheet and the mask. The image-receiving sheet 7 includes a support 70 made of baryta paper or the like, and an image-receiving layer 71 coated thereon. The mask 8 is
A mask material 80, a processing liquid resistant layer 81 for preventing permeation of a developer, and a weak sealing layer 8 with low adhesive strength.
2, and the mask material 80 is heat-sealed to the image receiving sheet 7 via this weak sealing layer 82. This weak sealing layer 82 is the release layer 8
3 and an adhesive layer 84, the mask 8
In order to cause peeling to occur between the release layer 83 and the adhesive layer 84 when the image receiving sheet 7 is peeled off, the adhesive strength between the release layer 83 and the adhesive layer 84 is made the weakest. The rail 9 is firmly bonded onto the mask material 80 by heat sealing.

As the mask material 80, kraft paper, glassine paper, etc. can be used, but in order to prevent partial blisters from occurring due to penetration of the developer, the following materials are used. is preferable.

(a) Base paper mixed with polyethylene (PE) and styrene/acrylic sizing agent added internally (b) Paper mixed with polyethylene The mixing ratio of polyethylene is 1 to 12% by weight, and the thickness is 30 to 40μ. be.

As the above-mentioned mask material, the material (a) is preferable, and in this case, the mixing ratio is 1 to 12% by weight and the thickness is 30 to 40μ.

As the processing liquid-resistant layer 81 applied to the lower surface of the mask material 80, a layer having excellent alkali resistance and good adhesion between the mask material 80 and the release layer 83 is used to suppress penetration of the developer. . Processing liquid-resistant layers having such characteristics include the following, and these may be used alone or in an appropriate mixture of two or more.

(a) Vinyl chloride and vinyl acetate copolymer A copolymer of vinyl chloride and vinyl acetate, preferably containing 80 to 95% by weight of vinyl chloride and the remainder being vinyl acetate. Such a vinyl chloride/vinyl acetate copolymer has a content of 90% by weight of vinyl chloride and 10% by weight of vinyl acetate, and has an average polymerization degree of 600.
(Product name: Nippon Zeon Co., Ltd.).

(b) Polyvinyl chloride (c) Polymethyl methacrylate This includes Sumipex (trade name) manufactured by Sumitomo Chemical Co., Ltd.

(b) Terpolymer of vinyl chloride, vinyl acetate, and vinyl alcohol This copolymer has a content of 91% by weight of vinyl chloride, 3% by weight of vinyl acetate, and 6% by weight of vinyl alcohol. vinyl light
3VAGH (Product name: Union Carbide)
There is.

(e) 3 of vinyl chloride, vinyl acetate, and maleic acid
Original copolymer This copolymer was Vinylite VMCH (trade name: manufactured by Union Carvant), which had a content of 86% by weight of vinyl chloride, 13% by weight of vinyl acetate, and 1% by weight of maleic acid. be.

(f) Methyl methacrylate (MMA) copolymer The molecular formula is (-MMA) _x --(-R) _y --. Here, R includes ethyl acrylate (EA), ethyl methacrylate (EMA), butyl acrylate (BA), butyl methacrylate (BMA), etc., x is 50 to 100, and y is 50 to 0.
It is.

(g) Polyvinylidene chloride This includes SOA (trade name: manufactured by Kureha Chemical Co., Ltd.).

(h) Polystyrene (PSt) or styrene (St) copolymer (-St) _x --(-R) _y --, R is methyl methacrylate, methyl acrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate,
There are butyl methacrylate, etc., where x is 50 to 100,
y is 0-50.

Among these treatment liquid-resistant agents, (a) vinyl chloride-vinyl acetate copolymer is most preferred.

A release layer 8 coated on the treatment liquid resistant layer 81
As the material 3, a polymer having alkali resistance and releasability to the adhesive layer 84 is used in order to suppress penetration of the developer. This polymer can be selected from among the treatment liquid resistant agents (a) to (h) described above. It is desirable to add the following additives to the release layer 83 in order to adjust the strength of the weak seal.

(a) Fatty acid amide Among the fatty acid amides, oleic acid amide is preferable, and the amount of oleic acid amide is 1 to 5% based on the solid content of the mold release agent.
Add % by weight.

(b) Glycerin ester rosin or bentaerythrite ester rosin, including Ester Gum H (trade name: Arakawa Hayashisan)
There is.

As the above-mentioned various mold release agents, it is preferable to use a combination of 50 to 70% by weight of polymethyl methacrylate to 50 to 30% by weight of vinyl chloride/vinyl acetate copolymer, and the peel strength can be controlled to a predetermined value depending on this composition ratio. I can do it. Furthermore, it is preferable to add oleic acid amide (a) to this in an amount of 3% by weight based on the solid content of the mold release agent.

For the adhesive layer 84, a thermoplastic polymer having hydrophilic groups such as -CONH- and -OH is used in order to provide writing properties to liquid ink. Examples of such adhesives include:

(a) Polyamides These include polyamides based on dimer acids, preferably DPX-
1163, 1175, 1300, 1358, Macromate 6212
(Product name: manufactured by Henkel Hakusuisha).

(b) Low degree of saponification polyvinyl alcohol (degree of saponification 30 to 50 mol%, degree of polymerization 300 to 600) Preferred examples include L5407 and L7514 (trade name: manufactured by Nippon Gosei Kagaku Kogyo Co., Ltd.).

(c) Polyvinyl acetate, vinyl acetate/maleic acid polymer (d) Polyvinylpyrrolidone (PVP) A matting agent may be added to the various adhesives mentioned above to make the surface rough and make it easier to write with a pencil. An example of this matting agent is silica. This silica has an average particle size of 2 to 5μ
It is recommended to add 5 to 20% by weight based on the solid content of the adhesive, and this includes untreated, inorganic treated, and organic treated types. Particularly preferred are those that have undergone inorganic treatment. The untreated product is S-224, the inorganic treated product is S-978 (product name: Fuji Davison), and the organically treated product is OK-412 (all products are manufactured by Fuji Davison). Product name: Manufactured by Degussa of West Germany).

The optimal combination of the adhesive and matting agent is
They are polyamide and silica, and if 20% by weight of this silica is added to the solid content of polyamide, it can give good writing properties to a pencil. After sequentially applying the seal layer 82 by gravure coating, when the mask 8 is temporarily wound up into a roll,
This is effective in preventing the adhesive layer 84 from sticking to the back surface of the facing mask material 80 (referred to as blocking).

FIG. 2 shows the state in which the image-receiving sheet and the mask are separated. Specified peeling time e.g. monochrome
When the image-receiving sheet 7 and mask 8 are peeled off after 45 seconds and 90 seconds have elapsed for color, peeling occurs between the release layer 83 and the adhesive layer 84, and the adhesive layer 84 is completely attached to the image-receiving sheet 7. It is transferred to form a white screen frame.

〔Effect of the invention〕

In the present invention, since the processing liquid resistant layer 81 is provided between the mask material 80 and the weak seal layer 82, the developer that has penetrated from the mask material 80 is further transferred to the weak seal layer 82.
2 can be prevented from penetrating. Therefore, since the release layer 83 and the adhesive layer 84 are not swollen by the developer, the mask material 80 and the processing liquid-resistant layer 81, the processing liquid-resistant layer 81 and the release layer 83, and the adhesive layer 84 and the image receiving layer The adhesive strength between the release layer 83 and the adhesive layer 84 is maintained at least 10 minutes after the standard peeling time, so that the mask 8 When the image-receiving sheet 7 and the image-receiving sheet 7 are separated, the adhesive layer 84 can be completely transferred to the image-receiving sheet 7. This makes it easy to peel off the image receiving sheet 7, and
The appearance of the screen frame after peeling off is beautiful, and it is possible to write well on this screen frame. especially,
Adding silica to the adhesive layer 84 is effective in preventing blocking and can provide good writing properties to the pencil.

Examples of the present invention will be described below.

〔Example〕

As the mask material 80, a material to which the styrene/acrylic sizing agent (a) was added and 12% by weight of PE was mixed into a base paper to a thickness of 33 μm was used. As a treatment liquid-resistant agent, the above-mentioned (a) vinyl chloride-acetate copolymer (400
×150M) with a dry coating amount of 2.5g/m ²
A treatment liquid-resistant layer 81 was formed by gravure coating the mask material 80 so that the mask material 80 had the following properties. As a mold release agent, the aforementioned vinyl chloride/vinyl acetate copolymer (400 x 150M) and polymethyl methacrylate (MHO) were mixed at a ratio of 30:70 (wt%).
The dry coating amount is 1.3.
g/m ² by gravure coating and release layer 83
Layered. As an adhesive, the polyamide (DPX-1163) mentioned above (a) was added with organically treated silica (S-978) at 20% by weight based on the polyamide. 4.0
g/m ² and apply gravure coating to adhesive layer 8.
4 was layered.

This mask 8 was heat-sealed to a monochrome image receiving sheet 7. The conditions for this heat sealing are that the sealing temperature is in the range of 100 to 150 degrees and the sealing time is
The time is 0.3 seconds and the pressure is 2.5Kg/cm ² . By this heat sealing, it was possible to obtain a good adhesive strength that would prevent the mask 8 and the image receiving seal 7 from peeling off unnecessarily.

When 45 seconds, which is the standard monochrome peeling time, has elapsed after the start of development, when 5 minutes have passed since the start of development, and when 10 minutes have passed since the start of development, the mask 8 and the image-receiving sheet 78 are peeled off for easy peeling. Adhesive layer 84
The transferability of the image to the image-receiving sheet 7 and the writing ability of the transferred adhesive layer (screen frame) were investigated. the result,
The ease of peeling was good at all peeling times. Further, the adhesive layer 84 was completely transferred to the image receiving sheet 7, and a screen frame with a beautiful appearance could be obtained. Also, this screen frame is a pencil (hardness
HB), had good writing properties with ballpoint pens, water-based pens, and oil-based pens.

Regarding film units without a processing liquid-resistant layer,
When a comparative experiment was conducted, it was found that the peelability was good under the standard peeling time, but the transferability and writability were somewhat degraded. Further, when the peeling time was 5 minutes, the ease of peeling was good, but the transferability and writability were considerably deteriorated. When the peeling time was set to 10 minutes, the ease of peeling, transferability, and writability all deteriorated.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the layer structure of a mask and an image-receiving sheet. FIG. 2 is a perspective view showing a state in which the mask and the image-receiving sheet are separated. FIG. 3 is a perspective view of the film unit. FIG. 4 is a sectional view showing the developed state of the film unit. 1...Photosensitive sheet, 2...Drawer sheet, 4...
...Developer pot, 5...Funnel, 6...Tab, 7...Image receiving sheet, 8...Mask, 9, 10
...Rail, 15, 16...Development roller, 70...
... Support, 71 ... Image-receiving layer, 80 ... Mask material,
81... Processing liquid resistant layer, 82... Weak sealing layer, 83
...Release layer, 84...Adhesive layer.

Claims (1)

[Claims] 1. An image receiving sheet bonded to a mask material in which an opening corresponding to the screen is formed via a weak sealing layer consisting of a release layer and an adhesive layer, and an image receiving sheet that is superimposed on the image receiving sheet after exposure. , and a photosensitive sheet on which a developer is spread, and the instant film unit is peeled off between the release layer and the adhesive layer after the developer is spread, and between the weak sealing layer and the mask material, An instant film unit characterized in that a processing liquid-resistant layer made of a polymer with excellent alkali resistance is provided to prevent the developer from penetrating the weak sealing layer. 2. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of vinyl chloride-vinyl acetate copolymer. 3 The vinyl chloride vinyl acetate copolymer contains 80% vinyl chloride.
3. The instant film unit according to claim 2, wherein the amount is 95% by weight and the remainder is vinyl acetate. 4. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of polyvinyl chloride. 5. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of polymethyl methacrylate. 6. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of vinyl chloride/vinyl acetate copolymer and polymethyl methacrylate. 7. The instant film unit according to claim 6, wherein the vinyl chloride/vinyl acetate copolymer is 30 to 50% by weight, and the remainder is polymethyl methacrylate. 8. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of a ternary copolymer of vinyl chloride, vinyl acetate, and vinyl alcohol. 9. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of a ternary copolymer of vinyl chloride, vinyl acetate, and maleic acid. 10. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of methyl methacrylate copolymer. 11. The instant film unit according to claim 1, wherein the treatment-resistant liquid layer is made of vinylidene chloride. 12. The instant film unit according to claim 1, wherein the processing liquid-resistant layer is made of polystyrene or a copolymer thereof.