A silver halide industrial radiographic material for direct use in a daylight room

Abstract

A kind of silver halide industrial radiograph material directly used in daylight room, including silver halide industrial radiograph, metal foil intensifying screen layer and light-proof packaging layer, silver halide industrial radiograph is located in middle layer, metal foil intensifying screen layer is provided with two layers, respectively set in silver halide industrial radiograph two sides, light-proof packaging layer is provided with two layers, respectively set outside two metal foil intensifying screen layers, three are vacuum or airtight package together;Silver halide industrial radiograph is coated with silver halide emulsion layer and protective layer in turn on the two sides of blue transparent support body in symmetry;Protective layer is hydrophilic gelatin layer, and hydrophilic gelatin layer includes sulfonic acid group modified polyvinyl alcohol, low molecular weight polyacrylamide and other auxiliaries.The sulfonic acid group modified polyvinyl alcohol and low molecular weight polyacrylamide added in the protective layer of silver halide industrial radiograph effectively solve the problems such as adhesion, static and pollution caused by the contact between the protective layer of silver halide industrial radiograph and metal foil intensifying screen layer.

Description

Technical Field

[0001] This invention relates to a silver halide photographic material for industrial X-ray nondestructive testing that can be used directly in a bright room, belonging to the field of photosensitive materials technology. Background Technology

[0002] Industrial silver halide radiographic films are one of the most commonly used non-destructive testing methods, widely used in the non-destructive testing of workpiece materials in industries such as electronic components, synthetic materials, castings, construction, metal welding, shipbuilding, nuclear industry, and aerospace. Industrial silver halide radiographic films record the intensity of radiation transmitted from X-ray sources, gamma rays from radioactive isotopes, and high-energy rays from particle accelerators. This allows for the inspection of welding defects and other structural flaws in workpiece materials without damaging the material. The recorded information can be archived long-term, making it an important recording material in the field of non-destructive testing. In practical applications, silver halide industrial X-ray film often requires thin metal foil, such as lead foil, to be irradiated by a radiation source along with the film. In this case, both the thin metal foil and the silver halide particles on the film absorb the radiation energy from the source. After absorbing the radiation energy, the thin metal foil releases secondary electrons and secondary rays. Some of the energy of the secondary electrons can be absorbed again by the silver halide particles on the film, forming more developable latent images and thus enhancing the sensitization effect. At the same time, when the radiation energy passes through the workpiece, it generates scattered rays within the workpiece. These scattered rays are often of low energy and most of them are absorbed and blocked by the metal foil, preventing them from being scattered onto the film and thus improving the image quality of the silver halide industrial X-ray film.

[0003] Typically, silver halide industrial X-ray films are manually packed into dark bags by technicians along with metal foil intensifying screens before use in workpiece material inspection. This process requires operation in a darkroom, is labor-intensive and time-consuming, and problems arise after prolonged storage of the silver halide industrial X-ray films and metal foil intensifying screens under vacuum or sealed packaging conditions, such as metal contamination of the film from the metal foil, static electricity during screen-film peeling, or adhesion making separation difficult. US Patent 62648384 provides a radiographic film packaging for non-destructive testing, including radiographic film, an intensifying screen with a lead-bonded layer on paper, and a vacuum heat-sealed package with an aluminum layer and a heat-sealable, easily peelable thermoplastic layer. To achieve a durable vacuum and ensure excellent contact between the film and the intensifying screen for at least one year after the packaging manufacturing date, the heat-sealed packaging material uses a polyethylene terephthalate layer on the outside, an aluminum layer in the middle, and a heat-sealable thermoplastic layer on the inside. However, the patent does not address the problem of metal contamination of the film after contact between the film and the intensifying screen. German patent DE60102116T2, "Silver Halide Photographic Materials and Imaging Systems for Direct Radiographic Imaging," describes an industrial radiographic film with a pre-packaged lead screen in a plastic sleeve. The protective layer contains antistatic agents such as polythiophene, vanadium oxide, or tin oxide, and colloidal silica. As seen in the examples, this industrial radiographic film extensively uses crosslinking agents to reduce the water and moisture absorption properties of gelatin, resulting in a higher content of precious metal silver. European patent EP92203639 provides a packaging for non-destructive testing radiographic film that does not contain a metal foil intensifying screen. This patent involves coating a separate antistatic layer between the heat-sealing layer and the protective layer of the radiographic film. This antistatic layer contains fluorides and polyoxyethylene compounds to address the problem of electrostatic sparks when removing the radiographic film from its packaging. However, because there is no metal foil intensifying screen, there is also no problem of metal contamination of the film. Chinese patent CN201010613943.3 describes an antistatic protective coating for metal intensifying screens. This coating involves applying amorphous colloidal vanadium oxide to the surface of a metal foil intensifying screen to prevent static electricity from being generated when the film and the metal intensifying screen are used together. This coating on the surface of the metal foil intensifying screen can alleviate the problem of metal contamination of the film to some extent. However, adding a coating can introduce new coating defects, affecting the detection and recording results of silver halide industrial X-ray films. Furthermore, the processing of metal foil intensifying screens, such as lead foil, is difficult and easily damaged, resulting in waste and increased costs. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a silver halide industrial X-ray photographic material for direct use in a bright room. A protective layer is set on the silver halide industrial X-ray film, and functional additives sulfonic acid-modified polyvinyl alcohol and low molecular weight polyacrylamide are added to the protective layer. This effectively solves the problem of metal contamination of industrial X-ray film in the metal foil during long-term storage under vacuum or sealed packaging conditions.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A silver halide industrial X-ray radiographic material for direct use in a bright room, comprising a silver halide industrial X-ray film, a metal foil intensifying screen layer, and a light-proof packaging layer. The silver halide industrial X-ray film is located in the middle layer. Two metal foil intensifying screen layers are disposed on both sides of the silver halide industrial X-ray film. Two light-proof packaging layers are disposed outside the two metal foil intensifying screen layers. All three are vacuum-sealed or airtightly packaged together. The silver halide industrial X-ray film has a silver halide emulsion layer and a protective layer symmetrically coated on both sides of a blue transparent support. The protective layer is a hydrophilic gelatin layer, comprising sulfonic acid-modified polyvinyl alcohol, low molecular weight polyacrylamide, and other additives.

[0007] In the above-mentioned silver halide industrial radiographic material used directly in a bright room, the amount of sulfonic acid-modified polyvinyl alcohol solids accounts for 10.0% to 30.0% of the total amount of hydrophilic gelatin and sulfonic acid-modified polyvinyl alcohol solids in the protective layer, and the amount of low molecular weight polyacrylamide solids is the same as the amount of sulfonic acid-modified polyvinyl alcohol solids.

[0008] The silver halide industrial X-ray photographic material used directly in the above-mentioned bright room has a sulfonic acid-modified polyvinyl alcohol solid content of (0.15~0.45) g / m² in the protective layer of each side of the silver halide industrial X-ray film.

[0009] The aforementioned silver halide industrial radiographic material used directly in a bright room has a sulfonic acid-modified polyvinyl alcohol with a degree of alcoholysis ≥99% and a degree of polymerization of 300.

[0010] The silver halide industrial radiographic material used directly in the above-mentioned bright room has a molecular weight range of 400,000 to 600,000 for the low molecular weight polyacrylamide.

[0011] The aforementioned silver halide industrial X-ray radiographic material used directly in a bright room comprises a metal foil intensifying screen layer formed by laminating metal foil onto backing paper; a light-proof packaging layer is made of polyethylene containing black masterbatch laminated onto stretchable kraft paper or aluminum-plastic film; the silver halide industrial X-ray film is located in the middle layer, with the metal foil surfaces of the two metal foil intensifying screen layers facing the protective layers on both sides of the silver halide industrial X-ray film, and the polyethylene surfaces containing black masterbatch of the two light-proof packaging layers facing the backing paper surfaces of the two metal foil intensifying screen layers.

[0012] The silver halide industrial radiographic material used directly in the above-mentioned bright room includes other additives such as surfactants, lubricants, surface agents and crosslinking agents. The total amount of solids is 8.5% to 10.0% of the total amount of gelatin and sulfonic acid-modified polyvinyl alcohol in the protective layer, and the amount of surface agent used on each side of the film is (0.0125 to 0.0375) grams per square meter.

[0013] The beneficial effects of this invention are:

[0014] 1. This invention adds sulfonic acid-modified polyvinyl alcohol and low molecular weight polyacrylamide to the protective layer of silver halide industrial X-ray film, effectively solving the problem of metal contamination of industrial X-ray film in the metal foil during vacuum or sealed packaging storage of the protective layer and the metal foil intensifying screen layer of silver halide industrial X-ray film.

[0015] 2. The metal foil intensifying screen used in the silver halide industrial X-ray imaging material of this invention does not require special treatment on its surface, such as anti-adhesion, anti-contamination and antistatic coatings, which effectively reduces the impact of new coating defects on the detection results of silver halide industrial X-ray film; at the same time, it reduces the manufacturing difficulty of the metal foil intensifying screen layer, improves the utilization rate of the metal foil intensifying screen layer, and reduces the amount of metal foil used.

[0016] 3. The silver halide industrial radiographic material of the present invention is convenient, quick, and can be used directly in a bright room. The silver halide industrial radiographic material produced has good storage properties. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the layer structure of the silver halide industrial radiographic material of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of industrial X-ray film for silver halide.

[0019] In the diagram: 1. Silver halide industrial X-ray film; 1-1. Blue transparent support; 1-2. Silver halide emulsion layer; 1-3. Protective layer; 2. Metal foil intensifying screen layer; 3. Light-proof packaging layer. Detailed Implementation

[0020] The silver halide industrial radiographic material provided by the present invention comprises a coating liquid on which a silver halide emulsion layer and a protective layer are symmetrically coated on both sides of a blue transparent support, and is dried multiple times to form a silver halide industrial radiographic film.

[0021] (1) Coating and drying methods

[0022] The coating method in this invention can be extrusion coating, curtain coating, or slope extrusion coating, with slope extrusion coating being the preferred method. The drying method after coating can be hot air drying or infrared drying, with hot air drying being the preferred method. The drying tunnel can be vertical, roller-type, or flat-plate type, with flat-plate drying being the preferred method.

[0023] (2) Support

[0024] The support used in this invention as the industrial radiographic material for silver halide should have good dimensional stability, should not deform or stretch during processing, should have low hygroscopicity, low shrinkage, and high flatness. It can be made of polyethylene terephthalate (PET), polyethylene naphthalate (PET), or polycarbonate transparent polyester material. The support thickness is generally 160-190 micrometers, preferably 175 micrometers thick polyethylene terephthalate (PET). To further improve the visual comfort of the images, the prepared industrial radiographic material for silver halide needs to have a cool-toned image. This can be achieved using techniques known to those skilled in the art, by adding a certain mass fraction of one or more anthraquinone or phthalocyanine blue masterbatches to the polyethylene terephthalate slices, followed by biaxial stretching to form a cool-toned blue polyester film. The present invention requires coating a base layer on both sides of the support to obtain good adhesion between the support and the adjacent silver halide emulsion layer. The base layer can be one or more adhesive coatings known to those skilled in the art. The base layer should have a certain degree of hydrophilicity. A special hydrophilic coating can be applied on the adhesive coating, or a hydrophilic substance can be added to the adhesive layer to form a hydrophilic adhesive coating. The measures in Chinese Patent ZL201711385265.8 can also be used in the present invention.

[0025] (3) Silver halide emulsion layer

[0026] In this invention, the silver halide particles used as the emulsion layer in industrial X-ray film can be cubic or plate-like. The structure of the silver halide particles can be one or a mixture of silver bromide, silver chlorobromoide, silver bromoiodide, silver chlorobromoiodide, and silver chloroiodide. The size of the silver halide particles and the amount of silver coated are designed comprehensively according to the type of industrial X-ray film. From an economic perspective, a lower amount of silver coated is better. However, considering factors such as the film's sensitivity, resolution, and grain size, in practice, the silver halide particle size in the industrial X-ray film emulsion layer can range from 0.1 micrometers to 2.5 micrometers, and the total silver amount coated on both sides can range from 5 grams per square meter to 16 grams per square meter, depending on the application scenario.

[0027] In this invention, the preparation of silver halide emulsion is carried out in a reaction vessel equipped with a stirrer and adjustable stirring speed, and with temperature control and adjustable temperature. A gelatin aqueous solution of a certain mass concentration is added to the reaction vessel, and the temperature and stirring speed are controlled. Multiple pumps are used to inject silver nitrate aqueous solution and one or more halide aqueous solutions of potassium bromide, sodium chloride, or potassium iodide into the reactor for mixing. The silver halide crystals generated in the reaction precipitate into the gelatin aqueous solution. The pump injection method for the silver nitrate aqueous solution and the halide aqueous solution can be simultaneous or separate, continuous or segmented; the injection flow rate can be constant or variable. The specific pump injection method is implemented according to the formulation design requirements. Generally, the ion concentration electrode potential of the mixture in the reaction vessel is measured by an ion electrode. Based on the ion concentration electrode potential designed in the formulation, the feeding rate of each pump is adjusted to control the ion concentration electrode potential required by the formulation design. In practice, it is expressed as the negative logarithm of the bromide ion concentration, pBr value. The stirring speed and temperature in the reactor are adjusted or not adjusted according to the formulation design, as well as the concentrations of gelatin, silver nitrate aqueous solution and halide aqueous solution, etc., to prepare silver halide microcrystals with different crystal forms, structures and sizes. Then, through processes such as sedimentation, water washing of the gelatin salt and remelting and replenishing the gelatin, a basic silver halide emulsion is made. To improve the photographic performance of the emulsion, heavy metals such as iridium and rhodium can be doped during the crystal growth process of silver halide. The silver halide basic emulsion prepared by the above method needs to be chemically sensitized by adding a chemical sensitizer. During the sensitization process, functional additives such as binders, stabilizers, anti-fogging agents, and surfactants can be added to prepare emulsion coating solutions for different types of industrial X-ray films. In the practice of this invention, a large number of known functional additives can be used. These functional materials include binders (including gelatin), chemical sensitizers (including sulfur and gold compounds), stabilizers (including tetrazolium-indene compounds), anti-fogging agents (including thiol compounds and tetrazolium compounds), surfactants, etc. The anti-fogging measures in Chinese Patent ZL201711490400.5 can also be used in this invention. Surfactants are beneficial for coating wetting and reduce coating defects. The surfactant type can be anionic, nonionic, or amphoteric. Different types of surfactants with different structures can be used in combination, or multiple types of surfactants can be used in combination. In addition, the same crosslinking agent as the underlying protective layer can be added to improve the coating strength. However, considering the photographic performance and economy, this invention does not add a crosslinking agent to the emulsion layer.

[0028] (4) Protective layer

[0029] The protective layer used in this invention for industrial X-ray films containing silver halide needs to provide sufficient protection for the silver halide emulsion layer. This protection not only reflects the requirements of general photographic materials such as scratch resistance, antistatic properties, and anti-adhesion, ensuring strong development penetration during development, but also reflects the fact that in this invention, the film is not easily contaminated by the metal foil intensifying screen layer during long-term vacuum or sealed packaging together with the metal foil intensifying screen layer. It can also be easily separated from the metal foil intensifying screen layer during use. This is mainly reflected in the fact that after separation, the industrial X-ray film containing silver halide exhibits clear and good image quality after normal development and setting processes.

[0030] In this invention, the protective layer is a hydrophilic coating with photographic gelatin as the main adhesive. The preparation process of the protective layer coating liquid involves adding sulfonic acid-modified polyvinyl alcohol and low molecular weight polyacrylamide to a gelatin aqueous solution at a certain temperature. In addition, the addition of surfactants, lubricants, crosslinking agents, and surface-texturing functional additives is necessary.

[0031] The function and application method of the surfactant in this invention are the same as those described in the emulsion layer. However, for practical effect in reducing surface tension, the surfactant in the protective layer is preferably a fluorocarbon anionic surfactant. To reduce the coefficient of friction of the film surface, a lubricant is added to the protective layer. The lubricant can be an oil-in-water dispersion of substances such as silicone oil or stearic acid. Silver halide industrial X-ray films are frequently in motion during actual use, including cutting, processing, and observation. To reduce harmful scratches caused by surface friction and increase the scratch resistance of the protective layer, a crosslinking agent is added to the adhesive gelatin. The crosslinking agent can be glyoxal, trichlorotriazine, or vinyl sulfone, etc., with vinyl sulfone crosslinking agents being preferred. The crosslinking agent is preferentially added to the protective layer and then diffused into the silver halide emulsion layer. In special cases, it can also be added to the silver halide emulsion layer. The crosslinking agent can be added directly to the protective layer coating liquid or added using a static mixer. For mass production, it is preferred to add it by mixing it with the protective layer coating liquid using a static mixer. Meanwhile, the photographic gelatin structure contains many carboxyl and amino groups, giving it strong hydrophilicity. Typically, after the silver halide industrial X-ray film is prepared, the overall coating retains less than 2% water content. The carboxyl groups in the photographic gelatin readily adhere to the external medium in a low-moisture environment. Therefore, adding a crosslinking agent to the photographic gelatin can alleviate the adhesion and contamination problems caused by the contact between the protective layer and the external medium. However, if the amount of crosslinking agent in the protective layer is too small, the crosslinking effect is insufficient, leading to severe adhesion and contamination problems. Especially after adhesion to metal, substances on the metal surface can affect the silver halide in the emulsion layer through the protective layer, forming unwanted fog density. If the amount of crosslinking agent is too large, although the crosslinking is sufficient, the hydrophilicity of the protective layer decreases significantly. At the same time, a large amount of crosslinking agent will also seep into the emulsion layer during drying, directly affecting the developer penetration of the entire coating, causing a deterioration in photographic performance. This necessitates coating the emulsion layer with more silver, increasing product costs and making it uneconomical. Therefore, the selection of the amount of crosslinking agent used is still quite limited, and it cannot completely solve the problems of adhesion and contamination caused by the contact between the protective layer and the external medium. In addition, adding a surface-finishing agent to the protective layer can reduce the contact area between the film and the outside world, thereby reducing adhesion and reducing the amount of crosslinking agent used. The surface-finishing agent can be silica or polymethyl methacrylate microspheres, preferably polymethyl methacrylate microspheres. Typically, the particle size of the microspheres is 2 micrometers to 10 micrometers. If the particle size of the microspheres is too small, they will be buried in the protective layer and become ineffective. If the particle size of the microspheres is too large, the anti-adhesion is better, but it is very easy to cause the degradation of the film image quality. Various combinations of commercially available microspheres with different particle sizes are used, but their usage is still limited, and it cannot completely solve the problems of adhesion and contamination caused by the contact between the protective layer and the external medium. Therefore, this invention adds sulfonic acid-modified polyvinyl alcohol and low molecular weight polyacrylamide to the protective layer of silver halide industrial X-ray film.

[0032] This invention utilizes sulfonic acid-modified polyvinyl alcohol and low molecular weight polyacrylamide, both of which possess excellent hydrophilicity. Their addition to the coating does not affect the penetration of the developer, allowing them to replace the same mass of photographic gelatin and reducing its usage. In a low-moisture environment, the sulfonic acid groups in sulfonic acid-modified polyvinyl alcohol readily ionize and conduct electricity, making it less prone to static electricity. While the hydroxyl groups also exhibit strong hydrophilicity, their adhesion to the external medium is weak, allowing for easy separation. The low molecular weight polyacrylamide used in this invention is a linear polymer with certain surface activity and metal adsorption characteristics. Adding it to the protective layer smooths the surface, reduces surface roughness, and adsorbs small amounts of metal substances resulting from adhesion, minimizing the adverse effects of metal substances penetrating the protective layer on silver halide formation in the emulsion layer. Therefore, when the amounts of crosslinking agents and surface roughening agents are limited, the protective layer formed by combining sulfonic acid-modified polyvinyl alcohol and low molecular weight polyacrylamide in photographic gelatin effectively solves the problems of adhesion and contamination caused by the contact between the protective layer and the external medium.

[0033] After extensive experimentation, sulfonic acid-modified polyvinyl alcohol (PVC) such as L-3266 and CKS-50 (Japan Synthetic Chemicals) were selected, with CKS-50, a sulfonic acid-modified PVC with a degree of hydrolysis of 99% and a degree of polymerization of 300, being more preferred. The amount of sulfonic acid-modified PVC solids used accounts for 10.0% to 30.0% of the total amount of protective layer gelatin and sulfonic acid-modified PVC solids. The amount of sulfonic acid-modified PVC solids in the protective layer of each side of silver halide industrial X-ray film is (0.15 to 0.45) g / m². Too low a dosage of sulfonic acid-modified PVC makes it difficult to solve the anti-pollution problem of this invention; too high a dosage, because PVC has no freezing point, cannot be cold-set during the drying process, and traditional photographic material drying equipment is prone to defects such as surface streaks. Simultaneously, the introduction of sulfonic acid-modified groups into PVC improves its solubility, reduces the viscosity of the PVC solution, which is beneficial for controlling the viscosity of the protective layer coating liquid, and also improves the electrostatic conductivity of the coating.

[0034] Through extensive experimentation, the inventors selected low molecular weight polyacrylamide as another suitable material. Polyacrylamide is typically a linear polymer, generally classified into low, medium, high, and ultra-high molecular weight types. Polyacrylamide with a molecular weight range above 1 million is classified as medium molecular weight polyacrylamide, which has a flocculating effect on gelatin and other polymers in the protective coating liquid. Higher molecular weight polyacrylamides have hygroscopic properties, making them unsuitable for this invention. However, polyacrylamide with a very low molecular weight range has an insignificant effect in this invention. Therefore, low molecular weight polyacrylamide with a molecular weight range of less than 1 million was selected, preferably between 400,000 and 600,000, such as Lucky's customized G-50. The amount of low molecular weight polyacrylamide solid used is the same as that of sulfonic acid-modified polyvinyl alcohol solid.

[0035] The protective layer of the present invention, after being coated and dried into a film, has better anti-adhesion, anti-pollution and antistatic effects.

[0036] (5) Metal foil intensifying screen layer

[0037] The silver halide industrial radiographic material provided by this invention includes a metal foil intensifying screen. The metal foil used in the intensifying screen can be made of metals such as lead, steel, copper, molybdenum, tantalum and tungsten, or it can be an alloy foil made mainly of metals such as lead, steel, copper, molybdenum, tantalum and tungsten with the addition of other metals. Preferably, it is a lead alloy foil with a lead mass percentage greater than 96%.

[0038] In this invention, the average thickness of the metal foil used in the intensifying screen is 0.020 mm to 0.100 mm, preferably 0.025 mm to 0.035 mm, and more preferably 0.030 mm. Since the metal foil is easily damaged, one side of the metal foil can be bonded to the backing paper using an adhesive. The backing paper can be paper, plastic, or other suitable non-metallic materials. The paper material can be cellulose paper or cellulose paper with added kaolin. The cellulose paper basis weight is 50 g / m² to 90 g / m², preferably 60 g / m².

[0039] In this invention, the other side of the intensifying screen metal foil does not require special treatment, such as no coating, thereby reducing the impact of coating defects on the detection results. However, the surface of the metal foil should be free from defects such as holes, scratches, abrasions, wrinkles, and oil stains that are visible to the naked eye; the prepared metal foil intensifying screen should have a smooth, clean, and flat surface. The metal foil intensifying screen layer can be in roll form or sheet form, and its size is the same as the cutting size of silver halide industrial X-ray film.

[0040] (6) Lightproof packaging layer

[0041] The silver halide industrial X-ray radiographic material provided by this invention includes a light-proof packaging layer. The light-proof packaging layer mainly uses stretchable kraft paper or aluminum-plastic film. The stretchable kraft paper or aluminum-plastic film not only prevents the silver halide industrial X-ray film from being exposed but also effectively heat-seals it. A polyethylene layer containing black masterbatch needs to be laminated onto the kraft paper or aluminum-plastic film. The polyethylene layer can be low-density polyethylene, high-density polyethylene, or a mixture of high- and low-density polyethylene. As the main material for heat sealing, it needs a certain seam strength. The amount of black masterbatch used in the polyethylene layer needs to meet the light-proof test requirements of the packaging. To meet the requirements for airtight sealing, a certain weight of stretchable kraft paper is needed, and its tear strength, burst strength, and tensile strength must meet the standards, with a tear strength ≥ 14.6 mN·m. 2 / g, burst strength index ≥5.7kPa, tensile strength ≥5kN / m. To meet the packaging vacuum requirements for a certain period of time, the aluminum-plastic film used needs to have a certain thickness, and its tensile strength at break, elongation at break and puncture strength need to meet special requirements. Its tensile strength at break ≥45MPa, elongation at break ≥30%, and puncture strength ≥10N.

[0042] The packaging heat sealing method in this invention can be one or a combination of manual heat sealing, high-frequency heat sealing, hot plate heat sealing, pulse heat sealing, infrared radiation heat sealing, ultrasonic heat sealing, hot air heat sealing, etc.

[0043] The present invention will be further described below with reference to the embodiments.

[0044] The following specific embodiments further illustrate the silver halide industrial radiographic material of the present invention, but the present invention is not limited to these examples. In addition, unless otherwise specified, "%" in the examples means "mass percentage".

[0045] I. Preparation of Silver Halide Industrial X-ray Film

[0046] (I) Preparation of Silver Halide Emulsion Coating Solution

[0047] 1. Preparation of Emulsion Coating Solution E-1

[0048] In a 2L reaction vessel equipped with a stirrer and adjustable stirring speed and temperature, 650mL of a 1.5g / L gelatin solution and 1.5g of sodium chloride were added and dissolved completely. The temperature inside the reaction vessel was controlled at 60℃, and the stirring speed was 2000rpm. Simultaneously, 350mL of a 2M silver nitrate aqueous solution and 355mL of a 2M potassium bromide aqueous solution were injected using two pumps. The flow rate of the silver nitrate aqueous solution pump was set to 5mL / min, and the pBr value of the reaction vessel was controlled at 3.0. The flow rate of the potassium bromide aqueous solution pump was adjusted according to the pBr value. The injection of potassium bromide aqueous solution was stopped immediately after the silver nitrate aqueous solution was added. The remaining potassium bromide solution was not used. Stirring and heat preservation continued for 5 minutes. Stirring was stopped, the solution was transferred, cooled, settled, washed with water to desalinate, reconstituted, and then colloid and water were added. After sensitization with sulfur gold, stabilizers, anti-fogging agents, surfactants and other additives were added to obtain cubic silver chlorobromide emulsion E-1 with a mass of 2 kg (silver content measured to be 59 g / kg) and an average particle size of 0.70 micrometers. It was ready for use.

[0049] 2. Preparation of Emulsion Coating Solution E-2

[0050] In a 2L reaction vessel equipped with a stirrer and adjustable stirring speed and temperature, 600mL of 0.6g / L gelatin solution and 0.8g potassium bromide were added and dissolved completely. The temperature inside the reaction vessel was controlled at 50℃, and the stirring speed was 1200rpm. 200mL of 0.8M silver nitrate aqueous solution and 210mL of 0.8M potassium bromide aqueous solution were prepared and injected simultaneously using two pumps at a flow rate of 6mL / min for 2 minutes. Stirring was then continued for 15 minutes while the temperature inside the reaction vessel was raised to 65℃ and the stirring speed was increased to 1500rpm. The remaining silver nitrate and potassium bromide aqueous solutions were then injected, with the silver nitrate pump flow rate at 3mL / min, maintaining a pBr value of 2.2 in the reaction vessel. The potassium bromide pump flow rate was also adjusted according to the pBr value. Immediately after the silver nitrate solution was added, the injection of potassium bromide solution was stopped. The remaining potassium bromide solution was not used. Stirring and maintaining the temperature for 10 minutes were continued. Then, 1g of potassium bromide solution was added instantaneously to the reaction vessel. 0 mL of a solution containing 1.6 g of potassium iodide was dissolved. The mixture was stirred and kept at 65°C for 5 minutes. The stirring speed was adjusted to 1800 rpm. Simultaneously, 250 mL of a newly prepared 2M silver nitrate solution and 260 mL of a prepared 2M potassium bromide solution were added. The silver nitrate solution was pumped at a flow rate of 3 mL / min, and accelerated at a rate of 0.1 mL / min. The pBr value of the reaction vessel was controlled at 2.4. The potassium bromide solution was pumped at the same flow rate. The concentration of silver nitrate aqueous solution was adjusted according to the pBr value until the silver nitrate aqueous solution was completely added. Immediately after this, the addition of potassium bromide aqueous solution was stopped. The remaining potassium bromide solution was not used. The mixture was stirred and kept warm for 20 minutes. Then, the stirring was stopped, the mixture was transferred, cooled, allowed to settle, and washed with water to remove salt. The mixture was then reconstituted, and colloid and water were added. After sensitizing with sulfur gold, stabilizers, anti-fogging agents, surfactants, and other additives were added to obtain a 2 kg (silver content measured at 56 g / kg) flake silver bromide iodide emulsion E-2 with an average particle size of 1.20 micrometers. This emulsion was then ready for use.

[0051] (II) Preparation of Protective Coating Solution

[0052] 1. Preparation of protective coating solution P-1

[0053] Weigh 54g of solid gelatin and add it to 766g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 20g of 30% CKS-50 aqueous solution (sulfonic acid modified polyvinyl alcohol, degree of alcoholysis 99%, degree of polymerization 300, produced by Nippon Synthetic Chemicals); 20g of 30% G-50 dispersion (polyacrylamide, molecular weight range 400,000 to 600,000, customized); 20g of 8% 1292 aqueous solution (anionic surfactant sodium diisooctyl succinate sulfonate); 5g of 5% FS-31 aqueous solution (nonionic fluorocarbon surfactant produced by DuPont, USA); 5g of 5% S-10 dispersion (lubricant dimethyl silicone oil); 30g of 5% T-546 dispersion (polymethyl methacrylate microspheres with a particle size distribution range of 3 to 8 micrometers); and 80g of 3% H-15 aqueous solution (vinyl sulfone crosslinking agent) to obtain P-1, which is ready for use.

[0054] 2. Preparation of protective coating solution P-2

[0055] Weigh 48g of solid gelatin and add it to 732g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 40g of 30% CKS-50 aqueous solution; 40g of 30% G-50 dispersion; 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-2, which is ready for use.

[0056] 3. Preparation of protective coating solution P-3

[0057] Weigh 42g of solid gelatin and add it to 698g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 60g of 30% CKS-50 aqueous solution; 60g of 30% G-50 dispersion; 10g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 10g of 5% T-546 dispersion; and 110g of 3% H-15 aqueous solution to obtain P-3, which is ready for use.

[0058] 4. Preparation of protective coating liquid layer P-4

[0059] Weigh 36g of solid gelatin and add it to 664g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 80g of 30% CKS-50 aqueous solution; 80g of 30% G-50 dispersion; 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-4, which is ready for use.

[0060] 5. Preparation of protective coating solution P-5

[0061] Weigh 63g of solid gelatin and add it to 797g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 10g of 30% CKS-50 aqueous solution; 10g of 30% G-50 dispersion; 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-5, which is ready for use.

[0062] 6. Preparation of protective coating solution P-6

[0063] Weigh 48g of solid gelatin and add it to 732g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 40g of 30% L-3266 aqueous solution (sulfonic acid modified polyvinyl alcohol, degree of alcoholysis 86.5%~89.0%, degree of polymerization 250, produced by Nippon Synthetic Chemicals); 40g of 30% G-50 dispersion; 20g of 4% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-6, which is ready for use.

[0064] 7. Preparation of protective coating liquid P-7

[0065] Weigh 48g of solid gelatin and add it to 732g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 40g of 30% CKS-50 aqueous solution; 40g of 30% G-80 dispersion (polyacrylamide molecular weight range 600,000 to 1,000,000, customized); 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-7, which is ready for use.

[0066] 8. Preparation of protective coating liquid P-8

[0067] Weigh 48g of solid gelatin and add it to 732g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 40g of 30% CKS-50 aqueous solution; 40g of 30% G-200 dispersion (polyacrylamide molecular weight range 1 million to 3 million, customized); 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-8, which is ready for use.

[0068] 9. Preparation of protective coating liquid P-9

[0069] Weigh 48g of solid gelatin and add it to 732g of deionized water to swell for 30 minutes. Heat to 40℃ and stir until completely dissolved. Then add 40g of 30% CKS-50 aqueous solution; 40g of 30% G-30 dispersion (polyacrylamide molecular weight range 200,000-400,000, customized); 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-9, which is ready for use.

[0070] 10. Preparation of protective coating liquid P-10

[0071] Weigh 48g of solid gelatin and add it to 772g of deionized water to swell for 30 minutes. Heat the solution to 40℃ and stir until completely dissolved. Then add 40g of 30% CKS-50 aqueous solution; 20g of 8% 1292 aqueous solution; 5g of 5% FS-3 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 95g of 3% H-15 aqueous solution to obtain P-10, which is ready for use.

[0072] 11. Preparation of protective coating liquid P-11

[0073] Weigh 60g of solid gelatin and add it to 745g of deionized water to swell for 30 minutes. Heat the solution to 40℃ and stir until completely dissolved. Then add 40g of 30% G-50 dispersion; 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 15g of 5% T-546 dispersion; and 110g of 3% H-15 aqueous solution to obtain P-11, which is ready for use.

[0074] 12. Preparation of protective coating liquid P-12

[0075] Weigh 60g of solid gelatin and add it to 770g of deionized water to swell for 30 minutes. Heat the solution to 40℃ and stir until completely dissolved. Then add 20g of 8% 1292 aqueous solution; 5g of 5% FS-31 aqueous solution; 5g of 5% S-10 dispersion; 30g of 5% T-546 dispersion; and 110g of 3% H-15 aqueous solution to obtain P-12, which is ready for use.

[0076] (III) Silver halide industrial X-ray films

[0077] Take the above-mentioned emulsion coating solution E-1 and protective film coating solutions P-1 to P12, keep the temperature of each coating solution at 40℃, and use the slope flow extrusion coating method to coat one side of a 175-micron thick blue transparent PET with a base layer on both sides. The lower layer is the emulsion coating with a silver coating amount of 7 g / m², and the upper layer is the protective coating with a coating amount of 25 g / m². The two layers are coated together. After coating, the film is first set with cold air at a temperature of 12℃, and then dried with hot air at a temperature not exceeding 40℃. After drying, the same emulsion coating solution and the same amount of silver coating solution and the same amount of protective coating solution are used on the other side. The same coating and drying method is used to complete the preparation of silver halide industrial X-ray films F-1 to F-12 one by one, which are ready for use.

[0078] Take the above-mentioned emulsion coating solution E-2 and protective film coating solution P-2, keep the temperature of each coating solution at 40℃, and use the slope flow extrusion coating method to coat one side of a 175-micron thick blue transparent PET with a base layer on both sides. The lower layer is the emulsion coating with a silver coating amount of 7 g / m², and the upper layer is the protective coating with a coating amount of 25 g / m². The two layers are coated together. After coating, the film is first set with cold air at a temperature of 12℃, and then dried with hot air at a temperature not exceeding 40℃. After drying, the same emulsion coating solution and the same amount of silver coating solution and the same protective coating solution and protective film coating amount are used on the other side. The same coating and drying method is used to complete the preparation of silver halide industrial X-ray film F-13, which is ready for use.

[0079] III. Fabrication of Metal Foil Sensitizing Screen Layer

[0080] Adhesive is applied to cellulose paper with a basis weight of 60 g / m². After drying to remove most of the solvent, the paper is laminated onto a lead-tin-antimony alloy foil with a thickness of 0.030 mm using rollers under certain pressure. The foil is then wound up and dried at a certain temperature for a certain period of time. After removing excess solvent from the adhesive, the paper is cut into roll metal foil sensitizing screen layer S-1 and loose metal foil sensitizing screen layer S-2 of the required size for later use.

[0081] IV. Preparation of the Light-Proof Packaging Layer

[0082] (a) The stretchable kraft paper and the polyethylene layer containing black masterbatch are laminated together by heating and laminating equipment to form a light-proof packaging layer. The light-proof packaging layer B-1 is cut into rolls of the required size and is ready for use.

[0083] (ii) The aluminum-plastic film and the polyethylene layer containing black masterbatch are laminated together by heating and laminating equipment to form a light-proof packaging layer. The film is then cut to the required size. Two films of equal size are taken and heat-sealed on three sides with the polyethylene layer facing each other to prepare a packaging bag B-2 with a suitable size for loose film, which is ready for use.

[0084] V. Preparation of Industrial X-ray Radiographic Materials of Silver Halides

[0085] Different silver halide industrial X-ray films, metal foil sensitizing screen layers, and light-proof packaging layers were prepared using the methods described in the table below. The silver halide industrial X-ray films and metal foil sensitizing screen layers were cut to the same size. The Lucky 01 roll laminating machine and the VS-600S external vacuum packaging machine were used to prepare the examples and comparative examples, as shown in Table 1 below.

[0086] Table 1. Preparation methods of examples and comparative examples

[0087]

[0088] VI. Test:

[0089] (I) Screen-to-chip separation effect test:

[0090] The above materials were placed in a constant temperature and humidity chamber and stored for 7 days using an accelerated aging method to simulate long-term storage. The temperature inside the chamber was set at 50°C and the relative humidity at 80%. After being removed, the materials were directly irradiated for 5 seconds under a GE ISOVOLT Titan E320 X-ray machine with a voltage of 100KV, a power supply of 5mA, and a focal length of 900mm. In a dark room, the separation effect of the metal foil intensifying screen and the silver halide industrial X-ray film was observed after the light-proof packaging layer was opened.

[0091] Screen-to-chip separation performance evaluation criteria

[0092] A: No adhesion, no static electricity, easy to separate, and excellent separation effect.

[0093] B: Adhesive or slightly statically charged particles are difficult to separate, but the separation effect is good.

[0094] C: Adhesion or static electricity makes it difficult to peel off, resulting in poor separation effect.

[0095] (II) Metal contamination testing:

[0096] After the metal foil intensifying screen layer of the silver halide industrial X-ray film is separated, it is processed in a Bluetech NDT-2 automatic washing machine with Lucky G30 reagent at 28°C for 8 minutes to obtain a light-density gray film. The gray film is then observed under transmitted light (adjustable brightness) to see if there is lead foil metal contamination in the deep-density image.

[0097] Metal pollution assessment standards

[0098] A: The gray flakes have uniform density and are free of contamination.

[0099] B: The gray sheet has a small number of areas with deep-density contamination.

[0100] C: The gray sheet contains a large number of areas with deep-density contamination.

[0101] VII. Test results are shown in Table 2 below.

[0102] Table 2. Test results for the examples and comparative examples.

[0103]

[0104] From Tables 1 and 2, it can be seen that in Examples 1-6 of the present invention, by adding sulfonic acid-modified polyvinyl alcohol and low molecular weight polyacrylamide to the protective layer of silver halide industrial X-ray film, and limiting the amount of solid sulfonic acid-modified polyvinyl alcohol to 10.0% to 30.0% of the total amount of hydrophilic gelatin and solid sulfonic acid-modified polyvinyl alcohol in the protective layer, and the amount of solid low molecular weight polyacrylamide to be the same as that of solid sulfonic acid-modified polyvinyl alcohol, the protective layer prepared in this way can be applied to silver halide industrial X-ray radiographic materials used directly in bright rooms, effectively solving the problems of adhesion, static electricity and contamination caused by the contact between silver halide industrial X-ray film and metal foil intensifying screen, and the screen-film separation effect is excellent.

Claims

1. A silver halide industrial radiographic material for direct use in a bright room, characterized in that: The silver halide industrial X-ray radiographic material includes a silver halide industrial X-ray film (1), a metal foil intensifying screen layer (2), and a light-proof packaging layer (3). The silver halide industrial X-ray film is located in the middle layer. The metal foil intensifying screen layer has two layers, which are respectively disposed on both sides of the silver halide industrial X-ray film. The light-proof packaging layer has two layers, which are respectively disposed outside the two metal foil intensifying screen layers. All three are vacuum or sealed together. The silver halide industrial X-ray film is formed by symmetrically coating silver halide emulsion layer (1-2) and protective layer (1-3) on both sides of a blue transparent support (1-1). The protective layer is a hydrophilic gelatin layer, which includes sulfonic acid-modified polyvinyl alcohol, low molecular weight polyacrylamide, and additives. The amount of solid sulfonic acid modified polyvinyl alcohol is 10.0% to 30.0% of the total amount of hydrophilic gelatin and solid sulfonic acid modified polyvinyl alcohol in the protective layer, and the amount of solid low molecular weight polyacrylamide is the same as the amount of solid sulfonic acid modified polyvinyl alcohol. The molecular weight of the low molecular weight polyacrylamide ranges from 400,000 to 600,000.

2. The silver halide industrial radiographic material for direct use in a bright room according to claim 1, characterized in that: The amount of sulfonic acid-modified polyvinyl alcohol solids in the protective layer of each side of the silver halide industrial X-ray film is (0.15~0.45) g / m².

3. The silver halide industrial radiographic material for direct use in a bright room according to claim 1, characterized in that: The sulfonic acid-modified polyvinyl alcohol has a degree of alcoholysis ≥99% and a degree of polymerization of 300.

4. The silver halide industrial radiographic material for direct use in a bright room according to claim 1, characterized in that: The metal foil intensifying screen layer is formed by laminating metal foil onto backing paper; the light-proof packaging layer is made of polyethylene containing black masterbatch laminated onto stretchable kraft paper or aluminum-plastic film; the silver halide industrial X-ray film is located in the middle layer, with the metal foil surfaces of the two metal foil intensifying screen layers facing the protective layers on both sides of the silver halide industrial X-ray film, and the polyethylene surfaces containing black masterbatch of the two light-proof packaging layers facing the backing paper surfaces of the two metal foil intensifying screen layers.

5. The silver halide industrial radiographic material for direct use in a bright room according to claim 1, characterized in that: The additives include surfactants, lubricants, surface roughening agents, and crosslinking agents. The total amount of solids used is 8.5% to 10.0% of the total amount of gelatin and sulfonic acid-modified polyvinyl alcohol solids in the protective layer, and the amount of surface roughening agent used on each side of the film is (0.0125 to 0.0375) grams per square meter.

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