JPH07319106A - Heat-treatment type imaging element containing adhesive intermediate layer - Google Patents

Abstract

PURPOSE: To provide a thermal-processable image forming element imparted with satisfactory adhesive strength between an overcoat layer and an image forming layer without exerting any adverse influence upon sensitometry. CONSTITUTION: This thermal-processable image forming element is composed of a substrate 1, a thermography image forming layer or photothermography image forming layer 2, an overcoart layer 3 formed on the image forming layer 2, and on intermediate adhesive layer 4 for adhering the overcoat layer to the image forming layer. The intermediate adhesive layer contains at least either one of polymer having pyrrolidone functionarity, polymer having epoxy functionarity or polyalkoxysilane.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention generally relates to imaging elements,
Especially thermally processable imaging elements
imaging element, hereinafter referred to as a heat-treatable image forming element). More specifically, the present invention relates to an imaging element comprising a thermographic or photothermographic layer; an overcoat layer; and an adhesive intermediate layer interposed between the overcoat layer and the thermographic or photothermographic layer.

[0002]

Thermally processable imaging elements, including films and photographic papers, for forming images by thermal processing are well known. These elements include photothermographic elements in which the element is imagewise exposed and then developed by uniform heating of the element to form an image.
These elements also include thermographic elements that are imaged by the imagewise heating of the element. Such elements are described, for example, in Research Disclosure , June 1978.
Mon, Item No. 17029 and US Pat. No. 3,080,2
54, No. 3,457,075 and No. 3,933,5
08.

An important feature of the heat-processible imaging elements described above is the protective overcoat layer. Protective overcoat layers for such imaging elements, to be sufficiently acceptable, impart (a) resistance to deformation of the element layer during heat treatment, and (b). It is intended to prevent or reduce the loss of volatile components in the element during heat treatment, and (c) overcoat from one or more element layers during manufacture of the element or during storage prior to image formation and heat treatment. To reduce or prevent migration of essential imaging components into the layer, (d) to allow satisfactory adhesion of the overcoat to adjacent element layers, and (e) to cracking. And undesired markings, for example wear markings during the manufacture, storage and processing of the element.

A particularly preferred overcoat for heat-processible imaging elements is US Pat. No. 4,741,992 (1
An overcoat comprising poly (silicic acid) as described in May 3, 988). Advantageously, this overcoat layer comprises a water-soluble hydroxyl-containing monomer or polymer with poly (silicic acid). The combination of poly (silicic acid) and a water-soluble hydroxyl-containing monomer or polymer compatible with the poly (silicic acid) is described in US Pat. No. 4,828,971 (1989).
It is also useful in a backing layer on the side of the support opposite the imaging layer, as described in May 9, 2013).

In the manufacture of heat-processible imaging elements, one of the most difficult problems is that protective overcoat layers typically do not exhibit sufficient adhesion to the imaging layers. The problem of obtaining sufficient adhesion is made particularly difficult by the fact that the imaging layer is typically hydrophobic, whereas the overcoat layer is typically hydrophilic. One solution to this problem is US Pat. No. 4,886,739 (issued December 12, 1989).
Polyalkoxysilanes are added to thermographic or photothermographic imaging compositions and hydrolyzed in situ to crosslink with the binders present in the imaging and overcoat layers. To form a Si (OH) ₄ portion having
Another solution to this problem is US Pat. No. 4,942,11.
No. 5 (issued on July 17, 1990),
An adhesion promoting layer consisting of some kind of adhesion promoting terpolymer is interposed between the image forming layer and the overcoat layer.

Known solutions to the problem of providing overcoats with sufficient adhesion to heat-treatable elements have certain drawbacks that have hindered their commercial use. For example, the inclusion of a polyalkoxysilane in an imaging composition causes a gradual increase in adhesion with aging of the element,
In-situ hydrolysis of polyalkoxysilanes is slow,
The rate is limited by the availability of water in the coating. Furthermore, alcohols produced as a by-product of hydrolysis, such as ethyl alcohol produced by the hydrolysis of tetraethoxysilane, cannot escape through the highly impermeable overcoat layer and enter the support. Tends to move. The support is typically polyester (most commonly poly (ethylene terephthalate)) and transfer of alcohol into such a support causes highly undesirable width-wise curling. This curling makes handling the imaging element extremely difficult. Even with a very low degree of curling, a significant consequence of such widthwise curling is clogging of the processing equipment.

Undesirable curling problems can be reduced by the use of the adhesion promoting interlayer of US Pat. No. 4,942,115, but the use of this interlayer adversely affects sensitometry and is economical. May require additional coating steps which are undesirable in nature and may require the use of expensive, difficult to handle and environmentally deficient terpolymers.

Undesirable curling consists of poly (silicic acid) and water-soluble hydroxyl-containing monomers or polymers compatible with poly (silicic acid), and with a barrier layer interposed between the support and the imaging layer. U.S. Pat. No. 5,264,334 (November 23, 1993)
It can be reduced by the use of the one described in (Published daily). However, this method also requires the use of additional coating steps.

Undesirable curling is also described in US Pat. No. 5,294,526 (issued Mar. 15, 1994).
Can be reduced by including a prehydrolyzed polyalkoxysilane in the imaging composition, as described in. By using a pre-hydrolyzed polyalkoxysilane, a by-product of hydrolysis, for example,
The ethyl alcohol formed by the hydrolysis of tetraethoxysilane is not present in the imaging layers, thus avoiding the problems caused by migration to these supports. However, this method requires precise control of all process parameters.

[0010]

It is an object of the present invention to provide an improved heat treatable imaging element having an adhesion promoting interlayer which overcomes the above mentioned disadvantages of the prior art.

[0011]

According to the invention, the heat-processible imaging element comprises: (1) a support; (2) a thermographic imaging layer or a photothermographic imaging layer; (3) the imaging layer described above. An overcoat layer on top of;
And (4) an adhesive intermediate layer for adhering the overcoat layer to the image forming layer; wherein the adhesive intermediate layer comprises (1) a polymer having pyrrolidone functionality,
It is characterized in that it comprises at least one of (2) a polymer having epoxy functionality and (3) a polyalkoxysilane.

An adhesive intermediate layer comprising a polymer having pyrrolidone functionality, a polymer having epoxy functionality or a polyalkoxysilane is typically used between the hydrophilic overcoat and the typically hydrophobic imaging layer. It has been found to act as an effective adhesion promoting layer, overcoming the difficult task of improving the adhesion of the. Moreover, the use of such polymers for this purpose not only gives very effective adhesion, but also does not adversely affect sensitometry, is easy to handle and apply and is also environmentally advantageous. Inexpensive, readily available materials can be used.

The overcoat layer used in the heat-processable imaging element of the present invention serves several important functions as described above. The overcoat layer can be composed of hydrophilic colloids such as gelatin or poly (vinyl alcohol), but is preferably US Pat.
No. 41,992 (issued May 3, 1988) composed of poly (silicic acid) and a water-soluble hydroxyl-containing monomer or polymer.

In addition to the support, imaging layer, overcoat layer and adhesive interlayer, the heat-processible imaging element of the present invention can optionally include additional layers such as backing layers. Particularly useful backing layers are poly (silicic acid) and water-soluble compatible with poly (silicic acid), as described in US Pat. No. 4,828,971 (issued May 9, 1989). It comprises a hydroxyl-containing monomer or polymer. Accordingly, the improved thermally processable imaging element of this invention comprises three different layers, each of which comprises poly (silicic acid):
(1) an overcoat layer whose purpose is to protect the element, as described in U.S. Pat. No. 4,741,992, and (2) described in U.S. Pat. No. 4,828,971. And a backing layer for the purpose of improving transportability, reducing static electricity and eliminating the formation of Newton's rings, and (3) hydrolysis subsides as described in US Pat. No. 5,264,334. A barrier layer may be included which is intended to protect the support against migration of organisms from the imaging layer and thereby prevent widthwise curling.

In a preferred embodiment, the heat-processible imaging element of this invention also imparts antistatic properties as described in US Pat. No. 5,310,640 (issued May 10, 1994). Also includes a conductive layer for.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The thermally processable imaging element of this invention can be a black and white imaging element or a dye-forming imaging element. The element of the present invention can have a wide variety of constitutions as long as it includes the support, the image forming layer, the overcoat layer and the adhesive intermediate layer.

A typical imaging element within the scope of this invention comprises (a) in a reactive combination in a binder, preferably a binder comprising hydroxyl groups.
In-situ and / or ex-situ prepared photographic silver halide, (b) (i) an organic silver salt oxidizing agent, preferably a silver salt of a long chain fatty acid, eg silver behenate, (ii) an organic An image-forming combination comprising a reducing agent for the silver salt oxidizing agent, preferably a phenolic reducing agent.
combination) and (c) at least one image forming layer containing an optical toning agent. Documents disclosing such an image-forming element include, for example, US Pat. Nos. 3,457,075; 4,459,350.
No. 4,264,725 and 4,741,992
Issue and Research Disclosure , June 1978, Item
No. 17029 is mentioned.

Polymers having pyrrolidone functionality, which are useful in the present invention, may vary widely in structure and may be homopolymers of N-vinyl-2-pyrrolidone, 2
Copolymers formed by the polymerization of three types of polymerizable monomers, one of which provides the pyrrolidone functionality, and interpolymers formed by the polymerization of three or more types of polymerizable monomers, of which at least one provides the pyrrolidone functionality. (Copolymer).

Polymers having epoxy functionality useful in the present invention may vary widely in structure and may include homopolymers of epoxy monomers, two polymerizable monomers, one of which provides epoxy functionality. Mention may be made of copolymers formed by polymerizing and interpolymers (copolymers) formed by polymerizing three or more polymerizable monomers, at least one of which provides epoxy functionality.

Polyalkoxysilanes useful in the present invention for forming an adhesive interlayer include those represented by Formula I or Formula II as follows: I Si (OR ₁ ) ₄ II R ₂ —Si (OR ₃ ) _{3 In the} above formula, R ₁ and R ₃ are each a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, for example, methyl,
Ethyl, propyl and butyl, R ₂ is substituted or unsubstituted alkyl, for example alkyl having 1 to 22 carbon atoms, such as methyl, ethyl, propyl, butyl and n-octadecyl; or unsubstituted or substituted Is phenyl.

Specific examples of polyalkoxysilanes useful for the aforementioned purposes include:

[0022]

[Chemical 1]

Polyalkoxysilanes can also be used as a component of overcoat layers, backing layers or barrier layers, or as components of imaging layers using the heat-processible imaging elements of this invention. The optimum layer thickness of the imaging layer, overcoat layer and adhesive interlayer depends on various factors such as specific factors, processing conditions, heat treatment means, desired image and specific components of the layer. Particularly useful imaging layer thicknesses are typically in the range of 1-10 microns, preferably 3-7 microns. Particularly useful overcoat layer thicknesses are also typically in the range of 1-10 microns, preferably 1-3 microns. Particularly useful adhesive interlayer thicknesses for polymers having pyrrolidone or epoxy functionality are typically in the range of about 0.008 to about 0.05 micron, preferably 0.01 to 0.02 micron. is there. Particularly useful adhesive interlayer thicknesses for use with polyalkoxysilanes are typically in the range of about 0.05 to about 1.0 micron, preferably 0.10 to 0.40 micron.

Useful overcoat compositions are typically clear and colorless. Even though the overcoat is not colorless and transparent, if the element is a photothermographic element, it must be at least transparent to the wavelength of radiation used for image formation and image viewing.
The overcoat is an imaging property of the element, such as sensitometric characteristics in the case of photothermographic elements,
For example, minimum density, maximum density or photographic speed is not significantly adversely affected.

The overcoat composition preferably comprises from 50 to 90% by weight of the overcoat of poly (silicic acid) and comprises a water-soluble hydroxyl-containing polymer or monomer compatible with the poly (silicic acid). It consists of Such overcoat compositions are described, for example, in US Pat. No. 4,741,992. Examples of water-soluble hydroxyl-containing polymers are acrylamide polymers, water-soluble cellulose derivatives, hydroxyethyl cellulose, water-soluble cellulose acetate, and poly (vinyl alcohol). In particular, hydrolyzed poly (vinyl alcohol) is preferable.

The heat-processible imaging element described above can contain multiple polymer-containing layers, for example, multiple overcoat layers. For example, the heat-processible imaging element comprises a first overcoat layer comprising a polymer other than poly (silicic acid), eg, a cellulose derivative, and a second overcoat layer comprising poly (silicic acid) and poly (vinyl alcohol). An overcoat can be included.

A preferred overcoat comprises 50 to 90% by weight of poly (silicic acid) of the formula:

[0028]

[Chemical 2]

Wherein x is an integer in the range of at least 3 to about 600 and the overcoat is also 10-5.
It also comprises 0% poly (vinyl alcohol). The photothermographic element comprises a photosensitive component which consists essentially of photographic silver halide. In photothermographic materials, latent image silver from silver halide acts as a catalyst for the imaging combination described above during processing. The preferred concentration of photographic silver halide is 0. photographic silver halide per mole of silver behenate in the photothermographic material.
It is in the range of 01 to 10 mol. Other photosensitive silver halide salts are useful in combination with the photographic silver halides described above, if necessary. Preferred photographic silver halides are silver chloride, silver bromide, silver bromochloride, silver bromoiodide, silver chlorobromoiodide, and mixtures of these silver halides. Ultrafine grain photographic silver halide is especially useful. Photographic silver halide can be prepared by any of the procedures known in the photographic art. Such operations to form photographic silver halide and the morphology of photographic silver halide are:
For example, Research Disclosure , December 1978, Item
No. 17029 and Research Disclosure , June 1978, Item No. 17643. Tabular grain light sensitive silver halide is also useful and is described, for example, in U.S. Pat. No. 4,435,499. Photographic silver halide may be unwashed or washed, can be chemically sensitized, is protected against fog formation and is described in the Research Disclosure publications cited above. As described above, it is possible to stabilize the sensitivity during storage. The silver halide can be prepared in situ as described, for example, in U.S. Pat. No. 4,457,075, or prepared elsewhere by methods known in the photographic art. You can also

The photothermographic elements of this invention typically comprise an oxidation-reduction imaging combination containing an organic silver salt oxidizing agent, preferably a silver salt of a long chain fatty acid. Such an organic silver salt has resistance to darkening upon irradiation. A preferred organic silver salt oxidizing agent is a silver salt of a long chain fatty acid having 10 to 30 carbon atoms. Examples of useful organic silver salt oxidizing agents are silver behenate, silver stearate, silver oleate, silver laurate, silver hydroxystearate,
They are silver caprate, silver myristate and silver palmitate. The combined use of organic silver salt oxidizing agents is also effective. Examples of useful organic silver salt oxidizing agents that are not organic silver salts of fatty acids are silver benzoate and silver benzotriazole.

The optimum concentration of organic silver salt oxidizing agent in the photothermographic element will vary depending on the desired image, the organic silver salt oxidizing agent in question, the reducing agent and the photothermographic element. The preferred concentration of the organic silver salt oxidizing agent is
It is in the range of 0.1 to 100 mol of organic silver salt oxidizing agent per mol of silver in the element. When an organic silver salt oxidizing agent is used in combination, the total concentration of the organic silver salt oxidizing agent is preferably within the above range.

Various reducing agents are useful in the photothermographic element. Examples of useful reducing agents in imaging combinations include substituted phenols and naphthols such as bis-β-naphthols; polyhydroxybenzenes such as hydroquinones, pyrogallols and catechols; aminophenols. Kind, for example,
2,4-diaminophenols and methylaminophenols; ascorbic acid reducing agents such as ascorbic acid, ascorbine ketals and other ascorbic acid derivatives; hydroxylamine reducing agents; 3-pyrazolidone reducing agents such as 1-phenyl- 3-pyrazolidone and 4
-Methyl-4-hydroxymethyl-1-phenyl-3-
Pyrazolidone; and sulfonamide phenols, as well as other organic reducing agents known to be useful in photothermographic elements, such as US Pat.
933, 508, U.S. Pat. No. 3,801,321 and Research Disclosure , June 1978, Item No. 1
7029 are mentioned. The combined use of organic reducing agents is also useful in photothermographic elements.

Preferred organic reducing agents in photothermographic elements include sulfonamide phenol reducing agents such as those described in US Pat. No. 3,801,381. Examples of useful sulfonamide phenol reducing agents are 2,6-dichloro-4-benzenesulfonamide phenol; benzenesulfonamide phenol; and 2,6-dibromo-4-benzenesulfonamide phenol, and combinations thereof.

The optimum concentration of organic reducing agent in the photothermographic element depends on factors such as the photothermographic element in question, the desired image, the processing conditions, the organic silver salt oxidizing agent in question, and the polyalkoxysilane. Dependent. Photothermographic elements preferably comprise toning agents, also known as activator-toners or toner-accelerators. The combination of toning agents is also useful in photothermographic elements. Examples of useful toning agents and co-toning agents are found, for example, in Research Disclo
sure , June 1978, Item No. 17029 and U.S. Pat. No. 4,123,282. Examples of useful toning agents are, for example, phthalimide, N-hydroxyphthalimide, N-potassium-phthalimide, succinimide, N-hydroxy-1,8-naphthalimide, phthalazine, 1- (2H) -phthalazinone and 2-acetyl. Examples include phthalazinone.

Post-processing image stabilizers and latent image storage stabilizers are useful in the photothermographic element. Any stabilizer known in the photothermographic arts is useful for the photothermographic elements described above. Examples of useful stabilizers include photolysed (photolyt
wise) active stabilizers and stabilizer precursors, which are described, for example, in US Pat. No. 4,459,350. Other examples of useful stabilizers include azole thioethers and blocked azoline thione stabilizer precursors and carbamoyl stabilizer precursors such as those described in US Pat. No. 3,877,940.

The heat-treatable elements described above preferably contain various colloids and polymers, alone or in combination with vehicles and binders, in various layers. Useful materials are hydrophilic or hydrophobic. They are transparent or translucent and are natural substances such as gelatin, gelatin derivatives,
Both cellulose derivatives, polysaccharides such as dextran, gum arabic and the like; and synthetic polymeric materials such as water soluble polyvinyl compounds such as poly (vinylpyrrolidone) and acrylamide polymers. Other useful synthetic polymeric compounds include dispersed vinyl compounds, such as those in the latex form, especially those that enhance the dimensional stability of photographic elements. Effective polymers include insoluble polymers of acrylates,
Examples include alkyl acrylates and methacrylates, acrylic acid, sulfoacrylates, and those having a crosslinkable site. Preferred high molecular weight materials and resins include poly (vinyl butyral), cellulose acetate butyrate, poly (methyl methacrylate), poly (vinyl pyrrolidone), ethyl cellulose,
Mention may be made of polystyrene, poly (vinyl chloride), chlorinated rubber, polyisobutylene, butadiene-styrene copolymers, copolymers of vinyl chloride and vinyl acetate, copolymers of vinylidene chloride and vinyl acetate, poly (vinyl alcohol) and polycarbonates.

The photothermographic elements and thermographic elements described above can contain addenda known to aid in the formation of useful images. The photothermographic element comprises a development modifier, a sensitizing dye, a hardener, an antistatic agent, a plasticizer and a lubricant, a coating aid, an optical brightener, an absorbing dye and a filter dye, which functions as a speed-enhancing compound. For example, Research Disclosure , 197.
December 8th, Item No.17643 and Research Disclo
sure , June 1978, Item No. 17029 can be contained.

The heat-treatable element can comprise various supports. Examples of useful supports are poly (vinyl acetal) films, polystyrene films, poly (ethylene terephthalate) films, polycarbonate films and related film and resin materials, as well as paper, glass, metals and heat treatment temperatures. Another support.

The layer of the heat-treatable element is a dip coating,
The support is coated by coating methods known in the photographic art including air knife coating, curtain coating or extrusion coating using a hopper. If desired, two or more layers are coated simultaneously. Spectral sensitizing dyes are useful in photothermographic elements to further impart sensitivity to the element. Useful sensitizing dyes are described, for example, in Research Disclosure , June 1978, Item N.
170.29 and Research Disclosure , 1978 1
It is described in Item No.17643 in February.

The photothermographic element described above preferably comprises a heat stabilizer to help stabilize the photothermographic element prior to exposure and processing. Such heat stabilizers improve the stability of the photothermographic element during storage. The preferred heat stabilizer is 2-bromo-2.
-Arylsulfonylacetamides, such as 2-bromo-2-p-trisulfonylacetamide; 2- (tribromomethylsulfonyl) benzothiazole; and 6
-Substituted-2,4-bis (tribromomethyl) -s-triazines, such as 6-methyl or 6-phenyl-
It is 2,4-bis (tribromomethyl) -s-triazine.

The heat treatable element is exposed by various forms of energy means. For photo thermographic elements,
As energy in such a form, silver halide for photography is exposed to light, and the electromagnetic spectrum in the ultraviolet region, visible region and infrared region, and electron beam, β-ray irradiation, γ-ray, X-ray
Includes particulate wave-like radiant energy, either incoherent (random phased) or coherent (phased), in the form of rays, alpha particles, neutron irradiation, and other forms generated by lasers. The exposure is monochrome, orthochromatic or panchromatic, depending on the spectral sensitization of photographic silver halide. Imagewise exposure is preferably for a time and intensity sufficient to form a developable latent image in the photothermographic element.

After imagewise exposure of the photothermographic element,
The resulting latent image is developed by simply heating the element to the heat treating temperature. This overall heating simply causes the photothermographic element to reach a temperature in the range of about 90 ° C to 180 ° C until a developed image is formed, for example about 0.5
Only needs to be heated for about 60 seconds. Shorter or longer treatment times are required depending on increasing or decreasing the heat treatment temperature. The preferred heat treatment temperature is in the range of about 100 ° C to about 130 ° C.

In the case of a thermographic element, the thermal energy source and imaging means can be any thermal energy source and means known in the thermographic imaging art. The thermographic image forming means can be, for example, an infrared heating means, a laser, a microwave heating means, or the like. Heating means known in the photothermographic and thermographic imaging arts are useful in providing the desired processing temperatures for the exposed photothermographic element. These heating means are, for example, simple hot plates, irons, rollers, heating drums, microwave heating means, heated air and the like.

The heat treatment is preferably carried out under ambient pressure and humidity conditions. Conditions that differ from normal atmospheric pressure and humidity are also useful. The components of the heat-treatable element can be placed anywhere in the element so long as the desired image is obtained. If desired, one or more components can be provided in more than one layer of the element.
For example, in some cases it may be desirable to include a percentage of reducing agents, toners, stabilizers and / or other additives in the overcoat layer that covers the photothermographic imaging layer of the element. In some cases this reduces migration of certain additives in the element layers.

The components of the imaging combination must be "in association" with each other to form the desired image. In this specification, the term “related state (in
By "association)" is meant that in a photothermographic element the photographic silver halide and the imaging combination are in a relative relationship with each other to allow the desired processing and to form a useful image.

The heat-processable imaging element of the present invention preferably comprises a backing layer. The backing layer used in the present invention is the outermost layer and is located on the side of the support opposite to the image forming layer. The backing layer typically comprises a binder and a sufficient amount of matting agent dispersed in the binder to provide the desired surface roughness. A wide variety of materials can be used to produce backing layers that meet the requirements of heat-processable imaging elements. The backing layer should be clear and colorless and should not adversely affect the sensitometric properties of the photothermographic element such as minimum density, maximum density and photographic speed. A preferred backing layer is US Pat. No. 4,828,
No. 971 and poly (silicic acid) and a water-soluble hydroxyl-containing monomer or polymer compatible with poly (silicic acid). A combination of poly (silicic acid) and poly (vinyl alcohol) is particularly useful. Other useful backing layers include polymethylmethacrylate, cellulose acetate, crosslinked polyvinyl alcohol, acrylonitrile, vinylidene chloride and 2- (methacryloyloxy) ethyltrimethylammonium methosulfate terpolymer, crosslinked gelatin, polyesters and polyurethanes. Those formed from.

Either organic or inorganic matting agents can be used in the heat-processible imaging element of the present invention. Examples of organic matting agents are particles, often in the form of beads, of polymers such as polymeric esters of acrylic and methacrylic acid such as poly (methylmethacrylate), styrene polymers and copolymers. Examples of inorganic matting agents are particles of glass, silicon dioxide, titanium dioxide, magnesium oxide, aluminum oxide, barium sulfate, calcium carbonate and the like. Matting agents and their use are further described in US Pat. No. 3,411,
907 and 3,754,924.

The backing layer preferably has a glass transition point (Tg) above 50 ° C., more preferably above 100 ° C., a Roughness Average (Ra) of greater than 0.8, and Preferably it has a surface roughness such that it is greater than 1.2, and most preferably greater than 1.5. U.S. Pat. No. 4,828,971
Roughness Average (R
a) is the arithmetic mean of all differences from the mean line of the rough surface.

The concentration of matting agent required to impart the desired roughness depends on the average diameter of the particles and the amount of binder. Preferred particles have an average diameter of about 1 to about 15 micrometers, preferably 2 to 8 micrometers. Matt particles are about 1 to about 100 mg per square meter
Can be effectively used at a concentration of. A small amount of a colorant is added to the heat-treatable imaging element of the present invention to improve the image tone, improve printout, better visible contrast, and enhance its appearance in the overcoat layer and / or It can be added to the adhesive interlayer. Blue colorants such as Victoria Pure Blue BO; Vi
ctoria Brilliant BlueG; Serva Blue WS; Aniline
Blue; Page Blue G-90 and Methylene Blue are particularly useful for this purpose.

In a preferred embodiment of this invention, the heat-processible imaging element also comprises a conductive layer which acts as a charging layer. For this purpose, the conductive layer has an internal resistivity of less than 5 × 10 ¹⁰ ohm / square.
Should have Such conductive layers are described in US Pat. No. 5,310,640 (issued May 10, 1994).

In accordance with the teachings of the aforementioned US Pat. No. 5,310,640, the conductive layers used in the present invention are "inner layers.
(inner layer), ie a layer underlying one or more coating layers. This layer can be located on either side of the support. It has an internal resistivity of less than 5 × 10 ¹⁰ ohms / square, preferably the internal resistivity of the conductive layer is 1 × 10 ¹⁰ ohms / square.
It is less than a square.

The conductive layer can be comprised of any of a wide range of layerable compositions having suitable physical and electrical properties compatible with the requirements of heat-processible imaging elements. Useful conductive layers include: (1) A conductive layer consisting of conductive metal-containing particles dispersed in a polymeric binder. Examples of useful conductive metal-containing particles include donor-doped metal oxides, oxygen-deficient-containing metal oxides and conductive nitrides, carbides or borides. Specific examples of particularly useful particles include conductive TiO ₂ , SnO ₂ , Al ₂ O ₃ , ZrO ₂ , and I.
n ₂ O ₃ , ZnO, TiB ₂ , ZrB ₂ , NbB ₂ , T
aB ₂ , CrB ₂ , MoB, WB, LaB ₆ , ZrN,
TiN, TiC, WC, HfC, HfN and ZrC are mentioned.

Examples of the many patents describing conductive metal-containing particles useful in the present invention include: (a) semiconducting metal salts, eg, US Pat.
833, 3,428,451 and 5,075,
Cuprous iodide as described in US Pat. No. 171; (b) metal oxides, preferably US Pat. No. 4,27.
No. 5,103, No. 4,394,441, No. 4,41
6,963, 4,418,141, 4,43
No. 1,764, No. 4,495,276, No. 4,57
1,361, 4,999,276 and 5,12
Antimony-doped tin oxide, aluminum-doped zinc oxide and niobium-doped titanium oxide as described in US Pat. No. 4,203,769 and 5,00.
A vanadium pentoxide colloidal gel as described in US Pat. No. 6,451; (d) a non-conductive material such as those described in US Pat. Nos. 4,845,369 and 5,116,666. Fibrous conductive powder containing antimony-doped tin oxide coated on water-soluble titanium potassium whiskers; (e) Binder as described in JP-A-4-55492 (published February 24, 1992). Conductive ceramic particles dispersed therein, such as TiN, NbB ₂ ,
Particles of TiC, LaB ₆ or MoB; (2) Evaporated metal, for example a conductive layer made of silver, aluminum or nickel; (3) Evaporated metal film as described in US Pat. No. 4,078,935. (4) A crosslinked vinylbenzyl quaternary ammonium polymer of US Pat. No. 4,070,189 or US Pat. No. 4; , 237, 194, a conductive layer made of a conductive polymer such as the conductive polyanilines.

The vanadium pentoxide colloidal gel is particularly useful for forming a conductive layer. When vanadium pentoxide is used for this purpose, interposing a barrier layer between the conductive layer and the image-forming layer results in a negative effect on sensitometry from the conductive layer of vanadium pentoxide to the image-forming layer. It is desirable to prevent migration to. Suitable barrier layers include US Pat. No. 4,82.
The same composition as the backing layer of No. 8,971, that is,
Those having a mixture of poly (silicic acid) and water-soluble hydroxyl-containing monomers or polymers are mentioned.

In the present invention, when a vanadium pentoxide colloidal gel is used (for its production, 1980
(Described in U.S. Pat. No. 4,203,769, issued Mar. 20, 2008), many important advantages are obtained. Colloidal vanadium pentoxide gels are typically entangled, high aspect ratio, about 50-100 angstrom wide,
Thickness of about 10 Å and length of about 1000-1
It consists of a flat ribbon of 0000 angstroms.
These ribbons are laminated flat in the direction parallel to the surface when the gel is applied to form the conductive layer. The result is about three orders of magnitude greater than that observed for layers of the same thickness, which typically contain crystalline vanadium pentoxide,
The conductivity is extremely high. Low surface resistivity can be obtained with very low vanadium pentoxide coverage. As a result, optical absorption and scattering loss are reduced. In addition, the colloidal vanadium pentoxide gel-containing coating shows high adhesion to the underlying support material.

As mentioned above, the improved thermally processable imaging element of this invention comprises (1) a polymer having pyrrolidone functionality, (2) a polymer having epoxy functionality and (3).
It comprises at least one polyalkoxysilane and comprises an adhesive intermediate layer interposed between the imaging layer and the overcoat layer. The purpose of the adhesive interlayer is to strongly adhere the overcoat layer to the imaging layer so that it cannot be easily peeled off. The term "pyrrolidone functionality" means
By the presence of one or more pendant pyrrolidone rings. Preferably, the polymer consists of repeating units, at least 50 mol% of which comprise pendant pyrrolidone rings. The term "epoxy-functional" means the presence of one or more pendent oxirane rings. Preferably, the polymer consists of repeating units, at least 50 mol% of which comprise pendant oxirane rings.

Polymers having pyrrolidone functionality for use in the present invention include homopolymers of N-vinyl-2-pyrrolidone or N-vinyl-2-pyrrolidone and 1
It can be a copolymer with one or more ethylenically unsaturated copolymerizable monomers. Preferably, the copolymer contains at least 60% by weight N-vinyl-2-pyrrolidone.

The pendant pyrrolidone ring of this polymer may be substituted or unsubstituted. For example, these rings may be substituted with alkyl groups. A homopolymer of N-vinyl-2-pyrrolidone, ie poly (N-vinyl-2-pyrrolidone), is represented by the formula:

[0059]

[Chemical 3]

In the above formula, n is an integer, for example, a number high enough to give a molecular weight of several hundreds to several hundreds of thousands.
These polymers are well known and are disclosed, for example, in US Pat. No. 2,265,540 (issued Dec. 9, 1941) and US Pat. No. 2,335,454 (issued Nov. 30, 1943). It can be produced by the method for polymerizing N-vinyl-2-pyrrolidone described above.

Ethylenically unsaturated monomers copolymerizable with N-vinyl-2-pyrrolidone include: vinyl acetate glycidyl acrylate glycidyl methacrylate vinyl propionate vinyl chloride styrene methyl acrylate methyl methacrylate ethyl acrylate n-propyl. Acrylate ethyl methacrylate butyl acrylate butyl methacrylate methylacrylamide methylmethacrylamide N-isopropylacrylamide N, N-dimethylacrylamide N-acryloylmorpholine N-acryloylpiperidine vinylpyridine and the like.

Specific examples of polymers having pyrrolidone functionality which are preferred for use in the present invention include: poly (N-vinyl-2-pyrrolidone), poly (N-
Vinyl-2-pyrrolidone-co-vinyl acetate), poly (N-vinyl-2-pyrrolidone-co-glycidyl acrylate), poly (N-vinyl-2-pyrrolidone-co-
Glycidyl methacrylate), poly (N-vinyl-2-)
Pyrrolidone-co-N-acryloylmorpholine), poly (N-vinyl-2-pyrrolidone-co-N-acryloylpiperidine), poly (N-vinyl-2-pyrrolidone-co-methyl acrylate), poly (N-vinyl- 2-pyrrolidone-co-ethylmethacrylate), poly (N-vinyl-2-pyrrolidone-co-4-vinylpyridine), poly (N-vinyl-2-pyrrolidone-co-N, N-dimethylacrylamide), poly ( N-vinyl-2-pyrrolidone-co-N-isopropylacrylamide) and the like.

In a particularly preferred embodiment of the invention,
Polymers with pyrrolidone functionality consist of repeating units represented by the formula:

[0064]

[Chemical 4]

In the above formula, R ₁ is hydrogen or methyl, D is alkylene having 1 to 6 carbon atoms, and L is
Is

[0066]

[Chemical 5]

X = 30 to 100 mol%, y = 0 to 70 mol%. Polymers having preferred epoxy functionality for use in the present invention consist of repeating units represented by the formula:

[0068]

[Chemical 6]

In the above formula, R ₁ is hydrogen or methyl,
R ₂ is alkyl having 1 to 8 carbon atoms or 3 carbon atoms
~ 8 cycloalkyl, D is 1 to 6 carbon atoms
Alkylene and L is

[0070]

[Chemical 7]

A = 30 to 70 mol%, b = 0 to
10 mol%, c = 20 to 70 mol%. The above-mentioned polymers having epoxy functionality are readily prepared by reacting a polymerizable epoxy compound with one or more polymerizable acrylic monomers.

Examples of suitable polymerizable acrylic monomers include: ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, styrene, methyl acrylate, lauryl acrylate, lauryl methacrylate, allyl methacrylate and the like. .

Examples of suitable polymerizable epoxy monomers include: glycidyl methacrylate, glycidyl acrylate, allyl glycidyl ether. Specific examples of polymers having epoxy functionality that are preferably used in the present invention include: poly (butyl acrylate-co-allyl methacrylate-co-glycidyl methacrylate), poly (butyl methacrylate-co-allyl methacrylate-co). -Glycidyl methacrylate), poly (butyl acrylate-co-glycidyl methacrylate), poly (lauryl methacrylate-co-allyl methacrylate-co-glycidyl methacrylate).

In a particularly preferred embodiment of the invention,
The overcoat layer comprises polysilicic acid and polyvinyl alcohol, the imaging layer comprises polyvinyl butyral, and the adhesive intermediate layer comprises poly (N-vinyl-).
2-pyrrolidone). In a second particularly preferred embodiment of the invention, the overcoat layer comprises polysilicic acid and polyvinyl alcohol, the imaging layer comprises polyvinyl butyral and the adhesive interlayer comprises poly (butyl acrylate-co-). Allyl methacrylate-
Co-glycidyl methacrylate).

In a third particularly preferred embodiment of the present invention, the overcoat layer comprises polysilicic acid and polyvinyl alcohol, the imaging layer comprises polyvinyl butyral, and the adhesive intermediate layer comprises glycidoxypropyltrialkyl. It consists of methoxysilane. The use of polymers with pyrrolidone functionality, polymers with epoxy functionality or polyalkoxysilanes in the adhesive interlayer is highly advantageous compared to the prior art. Thus, for example, U.S. Pat. No. 4,942,115 discloses poly (2-propenenitrile-co-1,1-dichloroethene-co-2.
-Propenoic acid) or poly (2-propenoic acid methyl ester-co-1,1-dichloroethene-co-itaconic acid) and the use of an adhesive intermediate layer comprising a terpolymer polymer. ing. Although these terpolymers are very effective at imparting good adhesion, they are costly, difficult to handle and environmentally disadvantageous, yet undesirably high D _min- like. May adversely affect sensitometry.

The present invention will be described more specifically by the following examples. Example 1 A heat-processable imaging element is coated on a 0.114 millimeter thick poly (ethylene terephthalate) film support,
It was prepared by coating a photothermographic imaging layer, an adhesive interlayer and a protective overcoat layer. The photothermographic imaging composition was coated with a solvent mixture containing 90 parts by weight of methyl isobutyl ketone and 10 parts by weight of acetone to form an imaging layer of the following composition:

[0077] Ingredient coverage (g / m ²⁾ silver behenate 0.952 AgBr 0.388 Succinimide 0.428 ^* Surfactant 0.018 2-bromo -2-p-tolyl sulfonyl acetamide 0.070 2, 4-bis (trichloromethyl) -6- (1-naphtho) -S-triazine 0.017 Sensitizing dye 0.005 4-Benzenesulfonamidophenol 1.132 ^** Binder 3.020 ^* Trademark SF from General Electric Company Polysiloxane fluid commercially available under -96.

^** Trademark BUTVA from Monsanto Company
Poly (vinyl butyral) commercially available under R B-76. The adhesive intermediate layer consisted of poly (N-vinyl-2-pyrrolidone) (molecular weight 360,000) coated at a coverage of 0.11 g / m ² . To produce the protective overcoat layer, polysilicic acid was added to 29.4 wt% water, 1.2 wt% some normal p-toluene sulfonic acid, 34 wt% methanol and 35.4 wt%.
Was prepared by mixing 16.2% by weight of tetraethoxysilane to prepare a 16.3 wt% polysilicic acid solution. This polysilicic acid was mixed with polyvinyl alcohol, a surfactant, matte beads and water to form a protective overcoat layer having the following composition.

[0079] Ingredient coverage (g / m ^{2) *} Polyvinyl alcohol 1.1 polysilicic acid 1.65 ^** surfactant 0.044 polymethyl methacrylate beads 0.055 ^* EIduPont deNemours and Company from trademark Elvanol
High molecular weight polyvinyl alcohol commercially available under 52/22.

^** Trademark Surfactant from Olin Corporation
Para-isononylphenoxy polyglycidol surfactant marketed under 10G. A second heat-processible imaging element (Control A) was prepared similar to the above element except that the adhesive interlayer was omitted. A third heat-treatable imaging element (Control B) was prepared by adding poly (N-vinyl-2-pyrrolidone) in the adhesive interlayer to poly (butyl acrylate-co-2-sulfo-1,1-dimethylethylacrylamide- Co-methyl-2-acrylamido-2-methoxyacetate), but prepared in the same manner as the above elements.

For each of Example 1, Control A and Control B,
The adhesion of the overcoat layer to the image forming layer,
It was evaluated using a tape adhesion test. To carry out the test, a 35 mm wide sample was prepared and then laid flat on a table and Minnesota Mining and Manufacturi
SCOTCH Magic Tape # 8 available from ng Company
A portion of 11 was placed across the width of the sample and then flattened by hand to ensure a uniform bond. The tape was peeled off by hand and the% peel of the overcoat layer was evaluated and related to adhesion. Ideally, the degree of exfoliation would be zero. This test was performed 10 times for each sample. The measurement was performed on a fresh (freshly prepared) sample, a sample after 2 weeks under ambient conditions, and a sample after 2 weeks at 49 ° C./15% relative humidity.

The effect of the adhesive interlayer on the sensitometry was determined by the D _min of each sample after exposure (10 ⁻³ sec, EG & G, Wratten 29 filter) and heat treatment at 119 ° C. for 5 sec.
Was determined by measuring The lower the D _min value, the better the result. In each case, D _min is 49 ℃ / 15
% Relative humidity was measured on the sample after 2 weeks. The results obtained in both the adhesion test and the sensitometry test are summarized in Table I below.

[0083]

[Table 1]

The data reported in Table I show that the inclusion of an adhesive interlayer according to the present invention in a heat treatable element substantially improves the adhesion of the overcoat layer to the imaging layer. As a striking control, with the adhesive interlayer used in Control B, the adhesion was improved, but D
_min increased to a highly undesirable degree.

Example 2 To evaluate the effect of the thickness of the adhesive interlayer, poly (N
-Vinyl-2-pyrrolidone) four types of samples with varying coating amounts were prepared. In this test, the component ratio in the image-forming layer was slightly different from that of Example 1, and palmitic acid was added in the image-forming layer. Dedio et al. US Pat. No. 4,8
Palmitic acid and similar carboxylic acids can be incorporated into photothermographic elements for the purpose of improving latent image stability, as disclosed in US Pat. No. 57,439 (issued Aug. 15, 1989).

The composition of the image forming layer was as follows. Component coverage (g / m ² ) Silver behenate 1.008 AgBr 0.400 Succinimide 0.352 ^* Surfactant 0.019 2-Bromo-2-p-tolylsulfonylacetamide 0.072 2,4-bis (Trichloromethyl) -6- (1-naphtho) -S-triazine 0.017 Sensitizing dye 0.005 Palmitic acid 0.110 4-Benzylsulfonamidophenol 1.166 ^** Binder 3.092 ^{* From} General Electric Company A polysiloxane fluid sold under the trademark SF-96.

^** Trademark BUTVA from Monsanto Company
Poly (vinyl butyral) commercially available under R B-76. Tape adhesion test (49 ° C / 15% in each case) performed by changing the thickness of the poly (N-vinyl-2-pyrrolidone) layer
The results obtained in RH) were performed on the elements after 2 weeks) are summarized in Table II below.

[0088]

[Table 2]

The results reported in Table II show that the coverage of poly (N-vinyl-2-pyrrolidone) is important and must be sufficient to obtain the desired good adhesion. Show. Generally, the coverage of the adhesive interlayer with the polymer having pyrrolidone functionality should be at least about 0.1 g / m ² .

Examples 3-6 Polymers with pyrrolidone functionality coated with a dry coverage of 0.11 g / m ² were evaluated as adhesive interlayers using the Deformation Adhesion Test. In this example, the imaging layer was of the same composition as described in Example 2. In this adhesion test, SCOTCH Magic Tape # 811 is 1.
The 25 x 4.0 cm strip was pressed firmly against the overcoat layer by hand and then peeled off by hand. This test was performed on freshly prepared fresh samples for 1 hour 60
Performed on samples dried at ° C. The amount of exfoliation of the overcoat layer was measured and these samples were ranked based on the following criteria: good-no delamination fairly good-partial delamination poor-entire layer delamination obtained in this test. The results are summarized in Table III below.

[0091]

[Table 3]

As shown by the data reported in Table III, both homopolymers of N-vinyl-2-pyrrolidone and copolymers of N-vinyl-2-pyrrolidone and ethylenically unsaturated copolymerizable monomers were Good adhesion can be shown in tests carried out after drying for 1 hour at ° C. In contrast, when a 50/50 wt% copolymer of N-vinyl-2-pyrrolidone and vinyl acetate was used, the results in both tests were poor. Similarly, N-vinyl-2
-Using a 30/70 wt% copolymer of pyrrolidone and vinyl acetate, the results in both tests were poor.
These results indicate that the polymers of the present invention must have a sufficient level of pyrrolidone functionality in order to achieve their full success. Typically, when N-vinyl-2-pyrrolidone is copolymerized with one or more other monomers, the amount of N-vinyl-2-pyrrolidone should be at least about 60% by weight. .

Examples 7-9 To evaluate the effect of molecular weight variation, three types of samples were prepared using different molecular weight poly (N-vinyl-2-pyrrolidone). In these tests, the same support as in Example 1,
A photothermographic imaging layer and a protective overcoat layer were used. The layers were coated simultaneously using a multi-layer slide hopper coating technique. Example 7
In each of ~ 9, poly (N-vinyl-2-pyrrolidone) was coated at a coverage of 0.22 g / m ² .
Tape Adhesion Test Measurements Example 1 for fresh samples
And the D _min value was measured by the method described in Example 1.

The results obtained in both the adhesion test and the sensitometry test are summarized in Table IV below.

[0095]

[Table 4]

The data reported in Table IV show that good results are obtained with poly (N-vinyl-2-pyrrolidone) having a wide range of molecular weights.

[0097]Example 10 In this example, the support, photothermographic imaging layer and
And the protective overcoat layer is the same as that described in Example 1.
It was one. Adhesive intermediate layer is 0.11 g / m ²Coating
Poly (butyl acrylate-co-
-Allyl methacrylate-co-glycidyl methacrylate
G)

Using the tape adhesion test described in Example 1 for each of the elements of this example, Control A and Control B,
The adhesion of the overcoat layer to the image forming layer was evaluated and the effect of the adhesive interlayer on sensitometry was measured in the same manner as described in Example 1. The results obtained in both the adhesion test and the sensitometry test are summarized in Table V below.

[0099]

[Table 5]

The data reported in Table V show that the inclusion of the adhesive intermediate layer of the present invention in the heat-treatable element substantially improved the adhesion of the overcoat layer to the imaging layer.
And it shows that it is improved without adversely affecting D _min . As marked contrast, the use of adhesive interlayer employed in Control B, and the improved adhesion, but D _{mi n}
Has increased to an extremely undesirable degree.

[0101]Example 11 In this example, the support, photothermographic imaging layer and
And the protective overcoat layer is the same as that described in Example 1.
It was one. Adhesive intermediate layer is 0.11 g / m ²Coating
Amount coated glycidoxypropyltrimetho
Made of xysilane.

Using the tape adhesion test described in Example 1 for each of the elements of this example, Control A and Control B,
The adhesion of the overcoat layer to the image forming layer was evaluated and the effect of the adhesive interlayer on sensitometry was measured in the same manner as described in Example 1. The results obtained in both the adhesion test and the sensitometry test are summarized in Table VI below.

[0103]

[Table 6]

The data reported in Table VI show that the inclusion of the adhesive interlayer of the present invention in a heat-treatable element substantially improved the adhesion of the overcoat layer to the imaging layer.
And it shows that it is improved without adversely affecting D _min . As marked contrast, the use of adhesive interlayer employed in Control B, and the improved adhesion, but D _{mi n}
Has increased to an extremely undesirable degree.

Example 12 A heat-processible imaging element was prepared as described in Example 1 except that tetraethoxysilane was used in place of glycidoxypropyltrimethoxysilane in the adhesive interlayer. The results obtained are the same as in Example 11 and the% peeling is
10% for fresh samples, zero for samples left at ambient conditions for 2 weeks, and 49 ° C / 15% RH for 2 weeks
It was zero for the sample and D _min was 0.21. Therefore, tetraethoxysilane behaves like glycidoxypropyltrimethoxysilane in that it effectively improves adhesion without adversely affecting sensitometry.

Example 13 Four samples with varying glycidoxypropyltrimethoxysilane coverages were prepared to evaluate the effect of adhesive interlayer thickness. In this test, the components of the imaging layer were the same as described in Example 2. Tape adhesion test was conducted by varying the thickness of the glycidoxypropyltrimethoxysilane layer (in each case, 2 weeks, 49 ° C /
The results obtained under (for elements stored at 15% RH) are summarized in Table VII below.

[0107]

[Table 7]

The results reported in Table VII show that the thickness of glycidoxypropyltrimethoxysilane did not affect its adhesive performance.

Example 14 Glycidoxypropyltrimethoxysilane coated with a dry coverage of 0.11 g / m ² was evaluated as an adhesive interlayer using the Deformation Adhesion Test. In this example,
The imaging layer was of the same composition as described in Example 2. In this adhesion test, SCOTCH Magic Tape # 81
A 1.25 x 4.0 cm strip of 1 was pressed firmly against the overcoat sample by hand and then peeled off by hand.
This test was performed on fresh samples and for 60 hours
Performed on samples dried at ° C. The amount of overcoat layer delamination was measured and these samples were ranked based on the following criteria: good-no delamination fairly good-partial delamination poor-whole layer delamination. The rank was good for both of the tests on the sample dried at 60 ° C. for 1 hour, while the rank for Control A with no adhesive interlayer deployed was poor for the fresh sample, 60 It was quite good for the sample after drying for 1 hour at ° C.

[0110]

The present invention provides significant improvements in heat-processible imaging elements. Hydrophilic overcoat layer, for example
Layers containing poly (silicic acid) and poly (vinyl alcohol) provide excellent protective layers for the element. However, the degree of adhesion of such overcoat layers to hydrophobic imaging layers, such as those containing poly (vinyl butyral), is a consequence of the general lack of compatibility of hydrophilic and hydrophobic layers. Is insufficient. In contrast, the adhesive interlayer of the present invention overcomes the problem of poor adhesion, yet is low cost, readily available, easy to coat and handle, environmentally advantageous and sensitometric. The above problem is overcome by using a material that does not adversely affect the above.

Claims (1)

[Claims] 1. A support; (2) a thermographic image-forming layer or a photothermographic image-forming layer; (3) an overcoat layer on the image-forming layer;
And (4) a heat-treatable imaging element comprising an adhesive intermediate layer for adhering the overcoat layer to the image forming layer, wherein the adhesive intermediate layer is (i) a pyrrolidone functional group. An element characterized in that it comprises at least one of a polymer having properties, (ii) a polymer having epoxy functionality and (iii) a polyalkoxysilane.