Color masterbatch and method for producing the same, color photographic paper

Abstract

The application discloses a color masterbatch, a preparation method thereof and color paper. The color masterbatch comprises 1-20 parts by mass of red pigment, 1-20 parts by mass of blue pigment, 0.1-5 parts by mass of fluorescent whitening agent and 80-100 parts by mass of carrier resin, wherein at least one of the red pigment and the blue pigment is inorganic pigment. The color masterbatch provided by the application can reduce the types of the color masterbatch, simplify the process flow, save the process cost, effectively improve the stability of the color tone of the color paper, and solve the problem of uneven color of the film in the plastic coating process.

Description

Technical Field

[0001] This invention belongs to the field of color masterbatch technology, specifically, it relates to a color masterbatch and its preparation method, and color photographic paper. Background Technology

[0002] Color photographic paper is made by coating photographic base paper with a plastic coating to form a plasticized paper base, which is then coated with a color emulsion to form color photographic paper. During use, color photographic paper needs to be developed with a developer to form an image, ultimately becoming a photograph. In this series of production processes, the plastic coating plays a crucial role. The two main functions of the plastic coating are: firstly, to protect the paper base from damage by the developer; and secondly, to adjust the basic color tone of the photographic paper, making the finished photograph more vibrant and realistic. The key ingredient in the plastic coating formula that plays a crucial role in adjusting the basic color tone of the photographic paper is the plastic coating masterbatch.

[0003] In the production of plastics, color masterbatch is often used to color them. In addition to coloring requirements, the color masterbatch for photographic paper plastic layer must also meet special requirements such as high dispersibility, stable photographic paper tone, adjustment of brightness, and whitening.

[0004] In existing technologies, in order to achieve the above objectives, it is usually necessary to mix multiple color masterbatches. However, directly mixing multiple color masterbatches can easily cause unstable color fluctuations and uneven coating colors, which directly affects the quality of the finished photo. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one objective of this invention is to provide a color masterbatch and its preparation method, as well as color photographic paper. The use of this color masterbatch can reduce the types of color masterbatches used, improve the stability of photographic paper color tones, and also solve the problem of uneven coating color during the coating process.

[0006] In a first aspect, the present invention provides a color masterbatch, according to an embodiment of the present invention, comprising: 1 part by weight to 20 parts by weight of red pigment, 1 part by weight to 20 parts by weight of blue pigment, 0.1 part by weight to 5 parts by weight of fluorescent whitening agent, and 80 parts by weight to 100 parts by weight of carrier resin, wherein at least one of the red pigment, blue pigment, and fluorescent whitening agent is an inorganic pigment.

[0007] According to the above embodiments of the present invention, the masterbatch includes red pigment, blue pigment, fluorescent whitening agent, and carrier resin. The red pigment can be used in the red channel, and the blue pigment can be used in the blue channel. The interaction of the red and blue pigments can achieve specific color effects, thereby stabilizing the color tone of the photographic paper. Furthermore, by limiting the mass fractions of red and blue pigments added, the amount of red and blue pigments added can be uniformly adjusted in batches according to the color tone of the base paper, resulting in cool white high-gloss photographic paper bases or warm yellow warm-toned photographic paper bases, thus fulfilling customers' personalized customization needs. The fluorescent whitening agent can enhance the hiding power and vividness of the pigments, improve the color reproduction ability and clarity of the photographic paper, and also increase the brightness of the photographic paper, improving the overall quality of the photographic paper. The carrier resin can disperse the pigments into fine, stable particles, protecting the pigments and ensuring their stable effect. In addition, at least one of the red pigment, blue pigment, and fluorescent whitening agent is an inorganic pigment. Inorganic pigments have high color vividness and saturation and strong hiding power, which can increase the overall color effect and hiding effect of the color photographic paper. By mixing inorganic and organic pigments at micron-sized particle sizes, the pigments can fill gaps during granulation, increasing friction between them and enhancing dispersibility. This improves the uniformity of the coating color and reduces the need for dispersants and other additives. It also prevents volatile substances generated at high temperatures during the coating process from affecting the photographic properties of the paper. Furthermore, the prepared masterbatch meets the requirements for paper coating while saving on process costs and effectively improving the stability of the paper color. Therefore, the masterbatch provided in this application, through the synergistic effect of its components, meets the requirements of the paper coating. Its use reduces the types of masterbatches used, effectively improves the stability of the paper color, and solves the problem of uneven coating color during the coating process.

[0008] In addition, the color masterbatch according to the above embodiments of the present invention may have the following additional technical features:

[0009] In some embodiments of the present invention, the inorganic pigment accounts for no less than 10% of the total mass of the red pigment, blue pigment, and fluorescent whitening agent. This enhances the overall color effect and opacity of the color photographic paper.

[0010] In some embodiments of the present invention, the sum of the mass parts of the red pigment, blue pigment, and fluorescent whitening agent is 1 to 30 parts. This reduces the number of types of masterbatch used, effectively improves the stability of the photographic paper's color tone, and also solves the problem of uneven color during the coating process.

[0011] In some embodiments of the present invention, the particle size of the red pigment is 0.1 μm-10 μm. This enhances the dispersibility of the pigment and improves the uniformity of the film color.

[0012] In some embodiments of the present invention, the red pigment includes at least one selected from permanent red, iron oxide red, golden red, ultramarine violet, quinacridone violet, and permanent violet. Therefore, it can be used in combination with other pigments, which is beneficial for improving the tonal stability of photographic paper.

[0013] In some embodiments of the present invention, the particle size of the blue pigment is 0.1 μm-10 μm. This enhances the dispersibility of the pigment and improves the uniformity of the film color.

[0014] In some embodiments of the present invention, the blue pigment includes at least one selected from cobalt blue, cobalt chromium blue, iron blue, ultramarine, ultramarine blue, and phthalocyanine blue. Therefore, it can be used in combination with other pigments, which is beneficial for improving the stability of photographic paper tones.

[0015] In some embodiments of the present invention, the absorption wavelength of the fluorescent whitening agent is 60nm-380nm. This improves the whiteness and brightness of the photographic paper, and is beneficial for enhancing the stability of the photographic paper's tone.

[0016] In some embodiments of the present invention, the melting point of the fluorescent whitening agent is 280°C-350°C. This improves the uniformity of the coating tone and enhances the stability of the photographic paper tone.

[0017] In some embodiments of the present invention, the fluorescent whitening agent includes at least one of fluorescent whitening agent OB-1 and fluorescent whitening agent KSN. Therefore, it can be well adapted to the photo paper coating process, does not decompose or melt, and does not produce other substances that affect photo paper printing, thus improving the stability of the photo paper's tone.

[0018] In some embodiments of the present invention, the melt index of the carrier resin at 190°C and a load of 2.16 kg is 2 g / 10 min to 20 g / 10 min. This allows it to match the melt index of the polyethylene used in the plastic coating of photographic paper, which is beneficial for coating applications.

[0019] In some embodiments of the present invention, the carrier resin includes at least one of low-density polyethylene and linear low-density polyethylene. This ensures good compatibility with the polyethylene in the photographic paper plastic layer and prevents the formation of pigment spots and plastic spots.

[0020] In a second aspect, the present invention provides a method for preparing the aforementioned color masterbatch. According to an embodiment of the present invention, the method includes:

[0021] Red pigment, blue pigment, fluorescent whitening agent and carrier resin are mixed and granulated to obtain color masterbatch.

[0022] In a third aspect, the present invention provides a color photographic paper. This color photographic paper comprises the aforementioned masterbatch or a masterbatch obtained by the aforementioned method. Compared with the prior art, using the masterbatch provided in this application, while meeting the requirements for color photographic paper preparation, reduces the types of masterbatches used, simplifies the process, saves process costs, effectively improves the stability of photographic paper color tone, and also solves the problem of uneven coating color during the coating process.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0024] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] Color photographic paper is made by coating photographic base paper with polyethylene on both sides to form a coated paper base. This coated paper base is then further coated to form color photographic paper. The coating layer plays a crucial role in the use of photographic paper: firstly, it prevents seepage and water penetration, protecting the paper base from liquids and moisture; secondly, it adjusts the basic color tone of the color photographic paper, making the finished photographs more vibrant and realistic. However, the key ingredient in the coating formula that plays this role in adjusting the basic color tone of the photographic paper is the coating masterbatch.

[0026] In addition to coloring requirements, the masterbatches used in the coating of photographic paper also need to meet specific needs such as high dispersibility, stable paper tone, brightness adjustment, and whitening. To achieve these functions, multiple masterbatches are often mixed during the coating process. However, directly mixing multiple masterbatches can easily lead to uneven coating color, and the complex feeding process for multiple masterbatches increases the manufacturing cost of color photographic paper. Furthermore, because the amount of each masterbatch added is relatively small, fluctuations in weighing can cause unstable tone fluctuations in the coated paper base, directly affecting the quality of the finished photograph.

[0027] In view of this, in one aspect of the present invention, a color masterbatch is provided, the color masterbatch comprising: 1 part by weight to 20 parts by weight of red pigment, 1 part by weight to 20 parts by weight of blue pigment, 0.1 part by weight to 5 parts by weight of fluorescent whitening agent and 80 parts by weight to 100 parts by weight of carrier resin, wherein at least one of the red pigment, blue pigment and fluorescent whitening agent is an inorganic pigment.

[0028] For example, the red pigment can be 1 part, 5 parts, 10 parts, 15 parts, 20 parts, etc., the blue pigment can be 1 part, 5 parts, 10 parts, 15 parts, 20 parts, etc., the fluorescent whitening agent can be 0.1 part, 0.5 parts, 1 part, 3 parts, 5 parts, etc., and the carrier resin can be 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, etc.

[0029] According to the above embodiments of the present invention, the color masterbatch includes red pigment, blue pigment, fluorescent whitening agent, and carrier resin. The red pigment can be used in the red channel, and the blue pigment can be used in the blue channel. The interaction of the red and blue pigments can achieve specific color effects, thereby stabilizing the color tone of the photographic paper. Furthermore, by limiting the mass fractions of red and blue pigments added, the amount of red and blue pigments added can be uniformly adjusted in batches according to the color tone of the base paper, resulting in cool white high-gloss photographic paper bases or warm yellow warm-toned photographic paper bases, thus meeting customers' personalized customization needs. The fluorescent whitening agent can enhance the hiding power and vividness of the pigments, improve the color reproduction ability and clarity of the photographic paper, and also increase the brightness of the photographic paper, improving the overall quality of the photographic paper. The carrier resin can disperse the pigments into fine, stable particles, protecting the pigments and ensuring their stable effect. In addition, at least one of the red pigment, blue pigment, and fluorescent whitening agent is an inorganic pigment. Inorganic pigments have high color vividness and saturation and strong hiding power, which can increase the overall color effect and hiding effect of the color photographic paper. Therefore, the color masterbatch provided in this application, through the synergistic effect between the above-mentioned components, can meet the requirements of the photo paper coating layer. Moreover, the use of this color masterbatch can reduce the types of color masterbatch used, effectively improve the stability of the photo paper color tone, and also solve the problem of uneven coating color during the coating process.

[0030] It's important to note that red pigment is a commonly used dye and colorant. For color photographic paper, the purity and saturation of red pigment are crucial to the color quality of the red channel. Because red light is a long wavelength in the visible spectrum, red pigment can complement other colors (such as blue and green) to achieve color balance and neutralization. Furthermore, red pigment can be used with fluorescent whitening agents to enhance the pigment's hiding power and vibrancy. Blue pigment is the primary color providing the blue channel in color photographic paper. Because blue light is a short wavelength in the visible spectrum, blue pigment can complement other colors (such as red and green) to achieve color balance and neutralization. In some color photographic papers, blue pigment also plays a role in masking other colors. This helps improve color purity and vibrancy, and enhances color contrast.

[0031] According to some specific embodiments of the present invention, the inorganic pigment accounts for no less than 10% of the total mass of the red pigment, blue pigment, and fluorescent whitening agent. For example, the mass percentage of the inorganic pigment can be 10%, 20%, 50%, 70%, etc. By limiting the mass percentage of the inorganic pigment, the internal friction between different pigments can be increased, the dispersion effect can be improved, and the overall color effect of the color photographic paper can be further enhanced, making the photograph more vivid and bright. It can also further enhance the opacity of the color photographic paper, making the color more uniform and consistent.

[0032] According to some specific embodiments of the present invention, the sum of the mass parts of the red pigment, blue pigment, and fluorescent whitening agent is 1 to 30 parts. For example, it can be 1 part, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc. By limiting the sum of the mass parts of the red pigment, blue pigment, and fluorescent whitening agent to the above range, the requirements for color masterbatch used in the plastic coating of photographic paper can be met, while also realizing customers' personalized customization needs. Moreover, the use of this color masterbatch can reduce the types of color masterbatch used, simplify the process flow and save process costs, while effectively improving the stability of the photographic paper tone, and can also solve the problem of uneven coating color during the plastic coating process.

[0033] According to some specific embodiments of the present invention, the particle size of the red pigment is 0.1 μm-10 μm. For example, the particle size of the red pigment can be 0.1 μm-9 μm, 0.2 μm-8 μm, 0.3 μm-7 μm, 0.5 μm-6 μm, 0.7 μm-4 μm, 0.9 μm-3 μm, 1 μm-2 μm, etc. By limiting the particle size of the red pigment to the above range, it can interact with other pigments. Due to the different particle sizes of each pigment, they can fill the gaps during the granulation process, increase the mutual friction between the pigments, enhance the dispersibility of the pigment, and improve the uniformity of the coating tone. In addition, the efficient dispersion effect can effectively reduce the addition of volatile dispersants, thereby reducing the generation of fog in the imaging of silver halide photographic paper.

[0034] According to some specific embodiments of the present invention, the red pigment includes at least one selected from permanent red, iron oxide red, golden red, ultramarine violet, quinacridone violet, and permanent violet. By selecting the above-mentioned red pigment, it can be used well in combination with other pigments, and simultaneously possesses good lightfastness and weather resistance, is not prone to fading, and has a long service life. Therefore, the selection of the above-mentioned pigment allows for its use in combination with other pigments, which is beneficial for improving the stability of the photographic paper's color tone.

[0035] It should be noted that ultramarine violet is an inorganic pigment, characterized by its environmental friendliness, non-toxicity, and very vibrant hue. It can complement other colors (such as blue and green) to achieve color balance and neutralization. Quinacridone violet, also known as quinacridone, is a chemical substance. Its molecular formula is C1. 20H 12 N2O2 has a molecular weight of 312.32.

[0036] According to some specific embodiments of the present invention, the particle size of the blue pigment is 0.1 μm-10 μm. The particle size of the blue pigment can be 0.1 μm-9 μm, 0.2 μm-8 μm, 0.3 μm-7 μm, 0.5 μm-6 μm, 0.7 μm-4 μm, 0.9 μm-3 μm, 1 μm-2 μm, etc. By limiting the particle size of the red pigment to the above range, it can interact with other pigments. Due to the different particle sizes of each pigment, they can fill the gaps during granulation, increasing the mutual friction between pigments, enhancing pigment dispersibility, and improving the uniformity of the coating tone. Furthermore, the efficient dispersion effect can effectively reduce the addition of volatile dispersants, thereby reducing the generation of fogging in silver halide photographic paper imaging.

[0037] According to some specific embodiments of the present invention, the blue pigment includes at least one selected from cobalt blue, cobalt chromium blue, iron blue, ultramarine, ultramarine blue, and phthalocyanine blue. By selecting the above-mentioned blue pigment, the blue channel color can be provided in color photographic paper, and it can also be complementary to other colors (such as red and green), thereby achieving color balance and neutralization.

[0038] According to some specific embodiments of the present invention, the absorption wavelength of the fluorescent whitening agent is 60nm-380nm. For example, the absorption wavelength of the fluorescent whitening agent can be 60nm, 100nm, 150nm, 200nm, 300nm, 380nm, etc. By limiting the wavelength of the fluorescent whitening agent to the above range, the fluorescent whitening agent can absorb invisible ultraviolet light and convert it into visible light with a longer wavelength, such as blue light or violet light, thereby compensating for the unwanted slight yellow tint in the matrix. Moreover, the blue light reflected by the fluorescent whitening agent can complement the original yellow light to become white light, thereby improving the whiteness and brightness of the photographic paper.

[0039] According to some specific embodiments of the present invention, the melting point of the fluorescent whitening agent is 280℃-350℃. For example, the melting point of the fluorescent whitening agent can be 280℃, 300℃, 310℃, 320℃, 350℃, etc. Fluorescent whitening agents with too low a melting point are easily decomposed under the high temperature of coating, while fluorescent whitening agents with too high a melting point do not melt during coating and cannot be fused with the plastic layer. Therefore, using fluorescent whitening agents within the melting point range of this application can match the photo paper coating process and improve the uniformity of the coating tone.

[0040] According to some specific embodiments of the present invention, the fluorescent whitening agent includes at least one of fluorescent whitening agent OB-1 and fluorescent whitening agent KSN. The use of the above-mentioned fluorescent whitening agent can achieve the whitening effect of the photographic paper coating layer, while also being well-suited to the photographic paper coating process, without decomposition, melting, or producing other substances that affect photographic paper printing.

[0041] According to some specific embodiments of the present invention, the melt index of the carrier resin at 190°C and 2.16 kg load is 2 g / 10 min to 20 g / 10 min. For example, the melt index can be 2 g / 10 min, 5 g / 10 min, 8 g / 10 min, 10 g / 10 min, 15 g / 10 min, 20 g / 10 min, etc. Carrier resins with melt indices that are too high or too low are not conducive to coating applications. However, the carrier resins with melt indices within the scope of this application can match the melt index of polyethylene used in photo paper plastic layers, which is beneficial for coating applications.

[0042] It should be noted that melt flow index is commonly used to measure the flowability of polymer melts. It refers to the number of grams of molten material that flows out through a standard capillary tube within a certain time (typically 10 minutes) under specific temperature and pressure conditions, expressed in g / 10min. Melt flow index is usually measured using a melt flow rate meter. According to the national standard GB / T3682-2000: after loading the melt sample into the barrel, a piston is placed inside the barrel, a selected load is applied to the piston, and the loaded piston descends under gravity, extruding the molten material. The length it flows through within a certain time is then measured to calculate the flow rate of the melt sample. In this embodiment, the selected load mass is 2.16 kg, and the temperature is 190℃ when measuring the melt flow index.

[0043] According to some specific embodiments of the present invention, the carrier resin includes at least one of low-density polyethylene and linear low-density polyethylene. The carrier resin used in this application can effectively wet pigments and has good compatibility with the polyethylene in the photographic paper plastic layer, without producing pigment spots or plastic spots.

[0044] In another aspect of the invention, a method for preparing the aforementioned color masterbatch is provided. According to an embodiment of the invention, the method includes: mixing and granulating a red pigment, a blue pigment, a fluorescent whitening agent, and a carrier resin to obtain the color masterbatch.

[0045] In this step, color masterbatch can be obtained by mixing and granulating red pigment, blue pigment, fluorescent whitening agent and carrier resin.

[0046] Specifically, the method includes: first, mixing red pigment, blue pigment, fluorescent whitening agent and first carrier resin in a high-speed mixer, then extruding the mixed powder into strips in a twin-screw extruder, cooling, and pelletizing to complete the first granulation and obtain the first masterbatch, then mixing the first masterbatch with the second carrier resin in a high-speed mixer, and extruding the mixed powder into strips in a twin-screw extruder, then cooling, and pelletizing to complete the second granulation and obtain the color masterbatch.

[0047] Thus, through two mixing and granulation processes, a color masterbatch with uniform dispersion, stable color tone, and direct application to photographic paper base can be obtained. This color masterbatch not only meets the requirements for preparing the plastic layer of photographic paper but also saves on process costs and effectively improves the stability of the color tone of photographic paper.

[0048] In a third aspect, the present invention provides a color photographic paper. According to embodiments of the present invention, the color photographic paper comprises the aforementioned masterbatch or a masterbatch prepared using the aforementioned method. Specifically, the color photographic paper comprises photographic base paper, a photographic paper plastic layer, and an emulsifier layer stacked sequentially, wherein the photographic paper plastic layer is formed on the photographic base paper, the emulsifier layer is formed on the photographic paper plastic layer, and the photographic paper plastic layer contains the aforementioned masterbatch or a masterbatch prepared using the aforementioned method. Therefore, by using the masterbatch provided in this application, while meeting the requirements for color photographic paper preparation, the types of masterbatches used can be reduced, the process flow simplified, process costs saved, the stability of photographic paper color tone effectively improved, and the problem of uneven coating color during the plastic coating process can be solved. It should be noted that the coating formulation of the photographic paper plastic layer and the composition of the emulsifier layer are conventional technologies in the art, and those skilled in the art can select them according to actual needs. Furthermore, the features and advantages described above for the masterbatch and its preparation method also apply to this color photographic paper, and will not be repeated here.

[0049] The present disclosure will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be construed as limiting the scope of the disclosure. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0050] Example 1

[0051] (1) 5 kg of phthalocyanine blue with a particle size of 2 μm, 5 kg of ultramarine violet with a particle size of 5 μm, 1 kg of fluorescent whitening agent KSN and 89 kg of linear low-density polyethylene with a melt index of 20 g / 10 min were placed in a high-speed mixer and stirred at 1500 r / min for 10 min at a temperature of 80℃. The mixed material was then placed in a twin-screw extruder with a length-to-diameter ratio of 60 and extruded into strips at extrusion temperatures of 190℃, 200℃, 200℃, 220℃, 220℃, and 220℃. After being pelletized by cold water, primary masterbatch was obtained.

[0052] (2) Place 20kg of the primary masterbatch from (1) and 80kg of low-density polyethylene with a melt index of 20g / 10min in a high-speed mixer. Stir at 1500r / min for 5min at 80℃. Place the mixed material in a twin-screw extruder with a length-to-diameter ratio of 60 for extrusion into strips. The extrusion temperatures are 190℃, 200℃, 200℃, 220℃, 220℃, and 220℃. After being granulated by cold water, the color masterbatch is obtained.

[0053] (3) Mix the color masterbatch according to the photo paper coating formula, blow out the plastic film on the blown film machine, and then test the plastic film.

[0054] Example 2

[0055] (1) 10 kg of ultramarine blue with a particle size of 2 μm, 5 kg of ultramarine violet with a particle size of 5 μm, 1 kg of fluorescent whitening agent OB-1 and 84 kg of low-density linear polyethylene with a melt index of 20 g / 10 min were placed in a high-speed mixer and stirred at 1500 r / min for 10 min at 80 °C. The mixed material was then placed in a twin-screw extruder with a length-to-diameter ratio of 60 and extruded into strips at extrusion temperatures of 190 °C, 200 °C, 200 °C, 220 °C, 220 °C, and 220 °C. After being pelletized by cold water, primary masterbatch was obtained.

[0056] (2) Place 20kg of the primary masterbatch from (1) and 80kg of low-density polyethylene with a melt index of 20g / 10min in a high-speed mixer. Stir at 1500r / min for 5min at 80℃. Place the mixed material in a twin-screw extruder with a length-to-diameter ratio of 60 for extrusion into strips. The extrusion temperatures are 190℃, 200℃, 200℃, 220℃, 220℃, and 220℃. After being granulated by cold water, the color masterbatch is obtained.

[0057] The compound masterbatch was mixed according to the photo paper coating formula, and the plastic film was blown out on a blown film machine for testing.

[0058] (3) Mix the color masterbatch according to the photo paper coating formula, blow out the plastic film on the blown film machine, and then test the plastic film.

[0059] Example 3

[0060] (1) 10 parts of ultramarine blue with a particle size of 2μm, 10 kg of permanent violet with a particle size of 5μm, 1 part of fluorescent whitening agent OB-1 and 79 kg of low-density linear polyethylene with a melt index of 20g / 10min were placed in a high-speed mixer and stirred at 1500r / min for 10min at 80℃. The mixed material was then placed in a twin-screw extruder with a length-to-diameter ratio of 60 and extruded into strips at extrusion temperatures of 190℃, 200℃, 200℃, 220℃, 220℃, and 220℃. After being pelletized by cold water, primary masterbatch was obtained.

[0061] (2) Place 20kg of the primary masterbatch from (1) and 80kg of low-density polyethylene with a melt index of 20g / 10min in a high-speed mixer. Stir at 1500r / min for 5min at 80℃. Place the mixed material in a twin-screw extruder with a length-to-diameter ratio of 60 for extrusion into strips. The extrusion temperatures are 190℃, 200℃, 200℃, 220℃, 220℃, and 220℃. After being granulated by cold water, the color masterbatch is obtained.

[0062] (3) Mix the color masterbatch according to the photo paper coating formula, blow out the plastic film on the blown film machine, and then test the plastic film.

[0063] Comparative Example 2

[0064] (1) 5 kg of ultramarine blue with a particle size of 2 μm, 5 kg of ultramarine violet with a particle size of 5 μm, 1 kg of fluorescent whitening agent KSN, 2 kg of polyethylene wax and 87 kg of low-density linear polyethylene with a melt index of 20 g / 10 min are placed in a high-speed mixer and stirred at 1500 r / min for 10 min at 80°C. The mixed material is then placed in a twin-screw extruder with a length-to-diameter ratio of 60 and extruded into strips at extrusion temperatures of 190°C, 200°C, 200°C, 220°C, 220°C and 220°C. After being pelletized by cold water, primary masterbatch is obtained.

[0065] (2) Place 20kg of the primary masterbatch from (1) and 80kg of low-density polyethylene with a melt index of 20g / 10min in a high-speed mixer. Stir at 1500r / min for 5min at 80℃. Place the mixed material in a twin-screw extruder with a length-to-diameter ratio of 60 for extrusion into strips. The extrusion temperatures are 190℃, 200℃, 200℃, 220℃, 220℃, and 220℃. After being granulated by cold water, the color masterbatch is obtained.

[0066] (3) Mix the color masterbatch according to the photo paper coating formula, blow out the plastic film on the blown film machine, and then test the plastic film.

[0067] Comparative Example 3

[0068] The red masterbatch, blue masterbatch, and whitening masterbatch were weighed separately according to the coating formula and then mixed. The resulting plastic film was blown out on a blown film machine and tested.

[0069] The color masterbatches of Examples 4-20 and Comparative Examples 1 and 4-6 are the same as those of Example 1, except for the different experimental parameters (see Table 1).

[0070] The experimental parameters of the color masterbatches in Examples 1-21, Comparative Examples 1-2, and Comparative Examples 4-6 of this application are shown in Table 1.

[0071] Table 1

[0072]

[0073]

[0074] " / " indicates no

[0075] Testing and Analysis

[0076] Under the same conditions, the dispersibility and hue stability of the color masterbatches prepared in Examples 1-20 and Comparative Examples 1-6 were tested. The specific test methods are as follows:

[0077] Dispersibility: The red masterbatch, blue masterbatch, and whitening masterbatch were weighed separately according to the coating formulation and then mixed. The mixture was blown into a plastic film on a blown film machine and tested. (Note: If the pigment agglomerate particles per square meter of film are ≤3, the dispersibility of the masterbatch is excellent.)

[0078] Tone stability: A deviation of ±0.02 for tone stability a value and b value is considered excellent, while a deviation >0.05 is considered poor.

[0079] Photographic performance stability: If the change in photographic performance sensitivity is greater than 10 after 7 days of aging, or if there is excessive fogging, it will affect the normal use of the photos.

[0080] The test results are shown in Table 2.

[0081] Table 2

[0082] Example 1 excellent excellent No impact Example 2 excellent excellent No impact Example 3 excellent excellent No impact Example 4 excellent excellent No impact Example 5 excellent excellent No impact Example 6 excellent excellent No impact Example 7 excellent excellent No impact Example 8 excellent excellent No impact Example 9 excellent excellent No impact Example 10 excellent excellent No impact Example 11 excellent excellent No impact Example 12 excellent excellent No impact Example 13 excellent excellent No impact Example 14 excellent excellent No impact Example 15 excellent excellent No impact Example 16 excellent excellent No impact Example 17 excellent excellent No impact Example 18 excellent excellent No impact Example 19 excellent excellent No impact Example 20 Difference Difference No impact Comparative Example 1 Difference Difference / Comparative Example 2 Difference / Reduced sensitivity, increased fog Comparative Example 3 / Difference / Comparative Example 4 Difference Difference / Comparative Example 5 / Difference / Comparative Example 6 / Difference /

[0083] " / " indicates no

[0084] As shown in Table 2, compared with Comparative Example 1, the masterbatches obtained in Examples 1-19 have comparable dispersing performance to those with added dispersants. Furthermore, the color photographic paper made from the masterbatches provided in this application does not produce small molecule substances that affect photographic performance after high-temperature treatment, ensuring the stability of the photographic performance. Compared with Comparative Example 2, the masterbatches obtained in Examples 1-19 do not contain inorganic pigments, thus failing to enhance the dispersion effect through inter-pigment friction. Comparative Examples 3, 4, 5, and 6 reduced the number of pigment types, directly and severely affecting the color tone of the photographic paper, potentially leading to photos that are bluish, reddish, or yellowish, impacting usability. In Example 20, the pigments have the same particle size, preventing them from filling gaps during granulation, thus affecting pigment dispersibility. In Comparative Example 1, all pigments are organic, resulting in uneven color in the photographs.

[0085] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," "some implementations," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0086] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A color masterbatch, characterized in that, The masterbatch is composed of the following components: 1-20 parts by weight of red pigment, 1-20 parts by weight of blue pigment, 0.1-5 parts by weight of fluorescent whitening agent, and 80-100 parts by weight of carrier resin, wherein at least one of the red pigment and blue pigment is an inorganic pigment. The particle size of the red pigment is 0.1μm-10μm; The particle size of the blue pigment is 0.1μm-10μm; The red and blue pigments have different particle sizes.

2. The color masterbatch according to claim 1, characterized in that, Based on the total mass of red pigment, blue pigment, and fluorescent whitening agent, the inorganic pigment accounts for no less than 10% of the total mass.

3. The color masterbatch according to claim 1 or 2, characterized in that, The total mass fraction of the red pigment, blue pigment, and fluorescent whitening agent is 1 to 30 parts.

4. The color masterbatch according to claim 1 or 2, characterized in that, The red pigment includes at least one of permanent red, iron oxide red, golden red, ultramarine violet, quinacridone violet, and permanent violet.

5. The color masterbatch according to claim 1 or 2, characterized in that, The blue pigment includes at least one of cobalt blue, cobalt chromium blue, iron blue, ultramarine, ultramarine blue, and phthalocyanine blue.

6. The color masterbatch according to claim 1 or 2, characterized in that, The absorption wavelength of the fluorescent whitening agent is 60nm-380nm; Optionally, the melting point of the fluorescent whitening agent is 280℃-350℃; Optionally, the fluorescent whitening agent includes at least one of fluorescent whitening agent OB-1 and fluorescent whitening agent KSN.

7. The color masterbatch according to claim 1 or 2, characterized in that, The melt flow index of the carrier resin at 190°C and 2.16 kg load is 2 g / 10 min to 20 g / 10 min.

8. The color masterbatch according to claim 1 or 2, characterized in that, The carrier resin includes at least one of low-density polyethylene and linear low-density polyethylene.

9. A method for preparing the color masterbatch according to any one of claims 1-8, characterized in that, include: Red pigment, blue pigment, fluorescent whitening agent and carrier resin are mixed and granulated to obtain color masterbatch.

10. A type of color photographic paper, characterized in that, Includes the color masterbatch according to any one of claims 1-8 or the color masterbatch obtained by the method according to claim 9.

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