A method for improving the low temperature color development performance of thermal printing medical film

Abstract

The invention discloses a method for improving the anti-low-temperature color development performance of thermal printing medical film, wherein the phenolic hydroxyl group of the developer D-8 is protected by boron trifluoride, and the obtained complex of boron trifluoride and the developer D-8 is used as a developer in a thermal coating, and the thermal coating is coated on a film base to prepare a thermal printing medical film. The protection method of the invention has simple production conditions, low cost, and high implementation feasibility; through the complex protection effect of boron trifluoride and the developer D-8, the anti-low-temperature color development performance of the thermal printing medical film is improved. When the thermal film is thermally developed, the protective agent boron trifluoride is heated and releases D-8 molecules, and D-8 enters the thermal dye microcapsule through thermal motion and penetration, and a color development reaction occurs to form an image, thereby solving the problem of low-temperature color development of the thermal film caused by the ionization of the developer D-8 molecules, and improving the anti-fog performance of the thermal printing medical film.

Description

Technical Field

[0001] The invention belongs to the technical field of medical films, and in particular relates to a method for improving the low-temperature color development performance of thermal printing medical films. Background Art

[0002] Thermal printing technology has become a research hotspot in the medical industry. Thermal printing medical film is prepared by dispersing thermal dye microcapsule materials in protective glue in the form of coating. At present, the thermal dye used in medical film is mainly ODB-2 fluorane recessive dye, and the color developer used is mainly D-8 color developer. The color developer is directly dispersed into the thermal dye microcapsule coating liquid by grinding to micro-nano level, and the thermal layer is formed by coating to record information. This method has the advantages of easy control of dispersion effect, convenient preparation, and high image density. However, in the process of storage and transportation, due to the humid environment, the ionization of the hydroxyl group in the D-8 molecule causes the recording material to color at low temperature, resulting in an increase in the gray fog value, thereby affecting the image quality. The color developer microencapsulation method can effectively reduce the generation of gray fog during the storage and transportation of the material, maintain the stability of the image, and maintain a high image density.

[0003] However, traditional microencapsulation is to coat a layer of polymer material on the surface of the developer by emulsion polymerization. This method is complex and costly. As market competition pressure increases, inventing a low-cost solution has become the key to price competition in the industry. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects in the prior art and provide a method for improving the low temperature color development performance of thermal printing medical film.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a method for improving the low-temperature color development performance of thermal printing medical film, using boron trifluoride to protect the phenolic hydroxyl group of the color developer D-8, and the obtained complex of boron trifluoride and the color developer D-8 is used as a color developer in a thermal coating, and the thermal coating is coated on a film base to prepare a thermal printing medical film.

[0006] Furthermore, the specific steps of protecting the phenolic hydroxyl group of the color developer D-8 with boron trifluoride are as follows: in an inert atmosphere, using boron trifluoride and the color developer D-8 as raw materials and acetonitrile as a solvent, a complex reaction is carried out at a certain temperature. After the reaction is completed, filtering, washing with deionized water, and drying to obtain a complex of boron trifluoride and the color developer D-8.

[0007] Furthermore, the molar feed ratio of boron trifluoride to the developer D-8 is 1 to 5:1.

[0008] Furthermore, the inert gas is nitrogen, helium or argon.

[0009] Furthermore, the temperature of the complexation reaction is 30-50°C.

[0010] Furthermore, the complexation reaction time is 1 to 3 hours.

[0011] Furthermore, the ratio of the raw material to the solvent is 1 mol:2000 mL.

[0012] The advantages and beneficial effects of the present invention are as follows: the present invention utilizes the structural characteristics of the electron-deficient structure of boron trifluoride and the presence of lone pairs of electrons in phenolic hydroxyl groups, and forms a complex by the two, thereby solving the problem of low-temperature color development in thermal printing caused by the ionization of phenolic hydroxyl groups in the molecule of D-8 under the co-existence of a humid environment and residual solvents at room temperature, and improving the anti-fog performance of thermal medical film. The protection method of the present invention has simple production conditions, low cost, and high feasibility of implementation; the medical film prepared by the present invention improves its anti-low-temperature color development performance through the complex protection effect of boron trifluoride and the color developer D-8. When the thermal film is thermally developed, the protective agent boron trifluoride is heated and leaves to release D-8 molecules, and D-8 enters the thermal dye microcapsule through thermal motion and penetration, thereby solving the problem of low-temperature color development in thermal printing caused by the ionization of phenolic hydroxyl groups in the molecule of the color developer D-8 under the co-existence of a humid environment and residual solvents. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a photograph of the heat-sensitive coating prepared after complexing with boron trifluoride D-8 in Example 6 after being left for seven days.

[0014] Figure 2 This is a photo of the heat-sensitive coating of D-8 configuration without complexation in Example 1 after being left for seven days.

[0015] Figure 3 The film is coated and printed using the heat-sensitive coating of Example 6.

[0016] Figure 4 The film is coated and printed using the heat-sensitive coating of Comparative Example 1. DETAILED DESCRIPTION

[0017] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0018] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or apparatuses.

[0019] Example 1

[0020] Under nitrogen atmosphere, the color developer D-8 (29.20 g, 0.1 mol) was dissolved in 200 ml of acetonitrile. Under nitrogen protection, at a reaction temperature of 30°C, boron trifluoride (3.39 g, 0.05 mol) was introduced for complexation reaction for 1 hour. After the reaction was completed, the product was directly filtered, washed with deionized water, and dried to obtain the D-8 complex of boron trifluoride. The complexation yield was 89% (based on D-8).

[0021] Example 2

[0022] Take the color developer D-8 (29.20g, 0.1mol) and dissolve it in 200ml acetonitrile. Under the protection of helium, at the reaction temperature of 30℃, introduce boron trifluoride (33.90g, 0.5mol) to carry out complexation reaction for 1 hour. After the reaction is completed, the product is directly filtered, washed with deionized water, and dried to obtain the D-8 complex of boron trifluoride. The complexation yield is 98% (based on D-8).

[0023] Example 3

[0024] Take the color developer D-8 (29.20g, 0.1mol) and dissolve it in 200ml acetonitrile. Under the protection of helium, at the reaction temperature of 50℃, introduce boron trifluoride (33.90g, 0.5mol) to carry out complexation reaction for 3 hours. After the reaction is completed, the product is directly filtered, washed with deionized water, and dried to obtain the D-8 complex of boron trifluoride. The complexation yield is 99% (based on D-8).

[0025] Example 4

[0026] Take the color developer D-8 (29.20g, 0.1mol) and dissolve it in 200ml acetonitrile. Under the protection of helium, at the reaction temperature of 50℃, introduce boron trifluoride (16.95g, 0.25mol) to carry out complexation reaction for 2 hours. After the reaction is completed, the product is directly filtered, washed with deionized water, and dried to obtain the D-8 complex of boron trifluoride. The complexation yield is 95% (based on D-8).

[0027] Example 5

[0028] Take the color developer D-8 (29.20g, 0.1mol) and dissolve it in 200ml acetonitrile. Under the protection of argon, at the reaction temperature of 40℃, introduce boron trifluoride (16.95g, 0.25mol) to carry out complexation reaction for 2 hours. After the reaction is completed, the product is directly filtered, washed with deionized water, and dried to obtain the boron trifluoride D-8 complex. The complexation yield is 95% (based on D-8).

[0029] Example 6

[0030] Take the color developer D-8 (29.20g, 0.1mol) and dissolve it in 200ml acetonitrile. Under the protection of argon, at the reaction temperature of 50℃, introduce boron trifluoride (16.95g, 0.25mol) to carry out complexation reaction for 3 hours. After the reaction is completed, the product is directly filtered, washed with deionized water, and dried to obtain the D-8 complex of boron trifluoride. The complexation yield is 97% (based on D-8).

[0031] Comparative Example 1

[0032] 21 g of D-8 was ball-milled to micrometer level and directly dispersed in 150 mL of thermosensitive dye microcapsule emulsion produced by Nanyang Kelier Technology Co., Ltd. to obtain a thermosensitive coating prepared with uncomplexed D-8.

[0033] Take 21g of the D-8 complex of boron trifluoride prepared in Examples 1 to 6, and then directly disperse it in 150mL of thermosensitive dye microcapsule emulsion produced by Nanyang Kelier Technology Co., Ltd. after ball milling to micrometer level. Use a wire rod to evenly coat the mixture on a PET substrate, dry it in air for 3h, and directly print it with a thermal printer. After printing, place it in a 60℃ oven for 5h aging, and then use an X-Rite spectrodensitometer to measure the fog value and imaging density. (The results are shown in Table 1).

[0034] In order to evaluate the storage performance of the boron trifluoride D-8 complex coating solution, 100 ml of the coating solution of Example 6 and Comparative Example 1 were taken and placed at room temperature for 7 days under magnetic stirring. The storage performance (stratification and agglomeration) of the two coating solutions was evaluated by visual inspection (the results are shown in Figure 1 and Figure 2 ), the coating liquid prepared in comparative example 1 was obviously stratified. After seven days of storage, thermal printing was performed using the coating liquid without complex protection and the coating liquid after complex protection. The results are shown in Figure 3 and Figure 4 It can be seen that the performance of the coating liquid of the D-8 complex of boron trifluoride is significantly better than that of the coating liquid without complex protection. The film prepared in Comparative Example 1 has severe gray fog caused by low-temperature color development.

[0035] Table 1 Performance of medical films prepared from D-8 complexes C1 to C6 of boron trifluoride in Examples 1 to 6

[0036] Sample name Imaging density Fog value Medical film prepared with D-8 color developer 2.45 0.19 Example 1: Medical film prepared 2.89 0.00 Medical film prepared in Example 2 2.88 0.00 Example 3: Medical film prepared 2.88 0.00 Example 4: Medical film prepared 2.92 0.00 Example 5: Medical film prepared 2.90 0.00 Example 6: Medical film prepared 2.91 0.00

[0037] Table 2 Storage performance of coating solutions prepared from boron trifluoride D-8 complexes C1 to C6 in Examples 1 to 6

[0038] Sample name Layering Reunion Coating solution prepared by D-8 color developer Obvious stratification Serious reunion Example 1 Coating solution prepared Unstratified No reunion Example 2 Coating solution prepared Unstratified No reunion Example 3 Coating solution prepared Unstratified No reunion Example 4 Coating solution prepared Unstratified No reunion Example 5 Coating solution prepared Unstratified No reunion Example 6 Coating solution prepared Unstratified No reunion

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for improving the low temperature color development performance of thermal printing medical film, characterized in that: The phenolic hydroxyl group of the color developer D-8 is protected by boron trifluoride, and the electron-deficient structure of boron trifluoride and the structural characteristics of the lone pair of electrons of the phenolic hydroxyl group are utilized to form a complex between the two, and the obtained complex of boron trifluoride and the color developer D-8 is used as a color developer in a thermal coating, and the thermal coating is coated on a film base to prepare a thermal printing medical film, and when the thermal film is thermally developed, the protective agent boron trifluoride is heated and leaves to release D-8 molecules; The specific steps of protecting the phenolic hydroxyl group of the developer D-8 with boron trifluoride are as follows: in an inert gas atmosphere, using boron trifluoride and the developer D-8 as raw materials and acetonitrile as a solvent to carry out a complex reaction at a certain temperature; after the reaction is completed, filtering, washing with deionized water, and drying to obtain a complex of boron trifluoride and the developer D-8; The temperature of the complexation reaction is 30 to 50°C; The complexing reaction time is 1 to 3 hours.

2. The method for improving the low temperature color development performance of thermal printing medical film according to claim 1, characterized in that: The inert gas is nitrogen, helium or argon.

3. The method for improving the low temperature color development performance of thermal printing medical film according to claim 1, characterized in that: The ratio of the raw material to the solvent is 1 mol:2000 mL.

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