Base film for antibacterial dry film and preparation method of base film

Abstract

The invention belongs to the technical field of polyester films, and particularly relates to a base film for an antibacterial dry film and a preparation method of the base film. The base film comprises the following raw materials in parts by weight: 80-100 parts of PET resin, 1-5 parts of an antioxidant, 1-5 parts of a lubricant, 1-5 parts of a silane coupling agent and 10-15 parts of an organic-inorganic composite antibacterial agent. The prepared base film for the antibacterial dry film has excellent product performance (high light transmittance, low heat shrinkage rate, low haze, low surface roughness and the like) and antibacterial performance, and the antibacterial rate on escherichia coli, staphylococcus aureus and candida albicans reaches 99% or above.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyester film, and particularly relates to an antibacterial dry film base film and a preparation method thereof. BACKGROUND

[0002] Photosensitive dry film is widely used in the fields of electronics and printed circuit board (PCB) manufacturing. Photosensitive dry film plays a key role in PCB manufacturing. Through the irradiation of ultraviolet light, a stable adherend is generated to tightly adhere to the surface of the copper plate, thereby effectively blocking electroplating, etching and hole masking, so as to accurately transfer the PCB design pattern to the actual product. The photosensitive dry film is usually composed of three layers of a polyester (PET) base film, a photoresist layer and a polyethylene (PE) protective film. The PET base film, as a temporary carrier and physical support of the photoresist layer, plays a crucial role in multiple links such as coating, storage, transportation, exposure and pre-peeling. An ideal PET base film for dry film needs to have high light transmittance, excellent surface flatness and cleanliness, good dimensional stability, appropriate peeling performance and moderate adhesion to the photoresist layer, so as to ensure high precision and high reliability of pattern transfer.

[0003] With the development of the electronic information industry towards high density, high precision and high reliability, and the increase of production and storage environment diversity, more stringent requirements are put forward for the stability of dry film and its components. However, during production, slitting, packaging and storage, the surface of the dry film may be contaminated by bacteria, mold and other microorganisms brought by the environment or contact with personnel. Under suitable temperature and humidity conditions, these microorganisms may breed on the surface of the base film, or even migrate to the interface of the photoresist layer. Microbial contamination may cause multiple potential hazards to the quality of the dry film and the PCB process, such as the formation of physical defects by microbial colonies or metabolites, which may cause pattern defects during subsequent exposure, resulting in problems such as short circuit and open circuit of the circuit. For dry film products that need to be stored for a long time or shipped by sea, the risk of microbial breeding increases in a humid environment, which may cause unpredictable degradation of product performance over time.

[0004] At present, the conventional PET base film for dry film on the market mainly focuses on optimizing its optical, mechanical and surface physical properties, such as improving flatness, reducing haze and controlling peeling force by means of raw material purification, nanoparticle addition and surface coating modification. However, these base films generally do not have active antibacterial function. Although individual high-end electronic material fields may strictly control the microbial environment in the clean room, this belongs to external environmental control, which is costly and cannot completely eliminate the risk of secondary contamination of the product in subsequent links. Therefore, it is an inherent demand to endow the PET base film with antibacterial properties, so as to improve the comprehensive reliability of the dry film product from the source, prolong the storage life and adapt to a wider range of application scenarios.

[0005] Therefore, developing a dry film base film with excellent optical performance and antibacterial performance has clear market demand and technical value for improving the quality reliability and environmental adaptability of high-end electronic manufacturing materials. SUMMARY

[0006] The main purpose of the present application is to provide a dry film base film with excellent optical performance and antibacterial performance. The present application will be realized by the following technical solutions: An antibacterial dry film base film, comprising the following raw materials by weight: PET resin 80-100 parts Antioxidant 1-5 parts Lubricant 1-5 parts Silane coupling agent 1-5 parts Organic-inorganic composite antibacterial agent 10-15 parts The preparation method of the organic-inorganic composite antibacterial agent comprises the following steps: Step S1: Zinc acetate dihydrate and anhydrous ethanol are added to a reactor, stirred uniformly, and then KOH ethanol solution is added for reaction. After the reaction is completed, it is cooled to room temperature, filtered, and the filter cake is washed with anhydrous ethanol and deionized water, respectively. The filter cake is vacuum dried to obtain nano ZnO; Step S2: Nano ZnO is added to Tris-buffer buffer solution, stirred uniformly, and then dopamine hydrochloride is added for reaction. After the reaction is completed, it is cooled to room temperature, filtered, and the filter cake is washed with deionized water. The filter cake is vacuum dried to obtain polydopamine modified nano ZnO; Step S3: Antimicrobial modifier , N , N Carbonyl diimidazole and toluene are added to the reactor to obtain activated antimicrobial modifier. Then, polydopamine modified nano ZnO is added for reaction. After the reaction is completed, it is cooled to room temperature, filtered, and the filter cake is washed with anhydrous ethanol and deionized water, respectively. The filter cake is vacuum dried to obtain an organic-inorganic composite antibacterial agent.

[0007] In some embodiments, the antioxidant is selected from one or more of antioxidant 168, antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 2246, and antioxidant BHT.

[0008] In some embodiments, the lubricant is selected from one or more of N,N-ethylene bis stearyl amide, calcium stearate, zinc stearate, and pentaerythritol stearate.

[0009] In some embodiments, the coupling agent is selected from one or more of KH-550, KH-560, KH-570, KH-792, KH-791, and DL-602.

[0010] In some embodiments, the mass ratio of nano-ZnO to dopamine hydrochloride is 1:(0.1-0.5); the molar ratio of the antibacterial modifier to the carbonyl diimidazole is 1:(1-1.5). N , N In some embodiments, the mass ratio of nano-ZnO to dopamine hydrochloride is 1:(0.1-0.5); the molar ratio of the antibacterial modifier to the carbonyl diimidazole is 1:(1-1.5).

[0011] The application also provides a preparation method of the antibacterial dry film base film, comprising the following steps: The PET resin, the antioxidant, the lubricant, the organic-inorganic composite antibacterial agent, and the silane coupling agent are mixed uniformly in parts by weight, and then melt-extruded, cast into a sheet, bidirectionally stretched, and drawn and wound to obtain the antibacterial dry film base film.

[0012] In some embodiments, the thickness of the antibacterial dry film base film is 10-20 μm.

[0013] In some embodiments, the melt-extrusion temperature is 270-310°C; and the sheet casting temperature is 20-40°C.

[0014] In some embodiments, the bidirectional stretching is performed at a transverse stretching ratio of 5-8, a longitudinal stretching ratio of 4-6, a stretching temperature of 100-120°C, and a stretching rate of 100-130 mm / s. The application has the following beneficial effects: 1) The antibacterial dry film base film prepared by the application has excellent product performance (high light transmittance, low heat shrinkage, low haze, and low surface roughness) and antibacterial performance, and the antibacterial rate of the film against E. coli, Staphylococcus aureus, and Candida albicans is as high as 99% or more.

[0015] 2) The application obtains polydopamine-modified nano-ZnO by polymerizing dopamine hydrochloride on the surface of zinc oxide nanoparticles, and then modifies the polydopamine-modified nano-ZnO using an antibacterial modifier containing a carboxyl group. The polydopamine-modified nano-ZnO is modified to introduce triazole groups with high antibacterial activity, and the triazole groups can synergize with zinc oxide and polydopamine to improve the antibacterial effect of the organic-inorganic composite antibacterial agent. DETAILED DESCRIPTION

[0016] The following detailed description of various example embodiments of the application should not be considered to be limiting of the application, but merely illustrative in nature. The description is presented in the following order: 1. General Description of the Invention; 2. Detailed Description of Various Example Embodiments of the Invention; 3. Definitions; 4. Examples; and 5. References. The description of the application is presented in the order of the above order for the sake of clarity. However, it should be understood that the description of the application in the above order is merely illustrative in nature and that any order of the description of the application is contemplated as long as the scope of the application is not affected. Furthermore, the terms described in the present application are merely for describing the particular embodiments and are not intended to limit the present application. In addition, for the numerical ranges in the present application, it is understood that each intermediate value between the upper limit and the lower limit of the range is specifically disclosed. Each intermediate value within any stated value or stated range, and any other stated value or intermediate value within the stated range, is expressly included in the present application. The upper and lower limits of these smaller ranges can be independently included or excluded from the ranges.

[0017] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application, preferred methods and materials are described. All documents mentioned herein are incorporated by reference to disclose and describe the methods and / or materials in connection with which the documents are cited. In case of conflict between the present specification and any document incorporated by reference, the present specification will control. In addition, the materials employed by the present application, unless otherwise specified, are commercially available.

[0018] Preparation of Organic-Inorganic Composite Antibacterial Agent A Step S1 : Zinc acetate dihydrate (5.0 g) and anhydrous ethanol (100 mL) were added to a three-necked flask, and stirred uniformly at 75°C, then a 2.5 mol / L KOH ethanol solution (30 mL) was slowly added, and the reaction was continued to stir at 75°C for 10 h. After the reaction, it was cooled to room temperature, filtered, and the filter cake was washed with anhydrous ethanol and deionized water for 3 times, and the filter cake was dried at 100°C under vacuum for 12 h, and then ground to obtain nano-ZnO.

[0019] Step S2: Nano-ZnO (5.0 g) was added to a Tris-buffer buffer solution (100 mL) with pH = 8.5, and then dopamine hydrochloride (0.5 g) was added after stirring uniformly, and the reaction was continued to stir at 50°C for 2 h. After the reaction, it was cooled to room temperature, filtered, and the filter cake was washed with deionized water for 3 times, and dried at 100°C under vacuum for 10 h to obtain polydopamine modified nano-ZnO.

[0020] Step S3: The antibacterial modifier (0.1 mol), N , N'-carbonyl diimidazole (CDI) (0.1 mol) and toluene (200 mL) were added into a three-necked flask, and the mixture was stirred at 70°C for 2 h to obtain the CDI-activated antibacterial modifier; then polydopamine-modified nano-ZnO (10.0 g) was added, and the mixture was ultrasonically treated for 0.5 h, and finally the mixture was continuously stirred at 70°C for 5 h. After the reaction, the mixture was allowed to cool to room temperature, filtered, and the filter cake was washed with anhydrous ethanol and deionized water for 3 times, respectively, and the filter cake was dried at 100°C under vacuum for 12 h to obtain the organic-inorganic composite antibacterial agent A.

[0021] Preparation of organic-inorganic composite antibacterial agent B in Preparation Example 2 In Preparation Example 1, the antibacterial modifier in step S3 was replaced by , and other operation steps and conditions were the same as those in Preparation Example 1 to obtain the organic-inorganic composite antibacterial agent B.

[0022] Example 1 A method for preparing an antibacterial base film for dry film, comprising the following steps: By weight, 90 parts of PET resin (brand: CZ-333), 3 parts of antioxidant 1010, 2 parts of lubricant N,N-ethylene bis stearyl amide, 10 parts of organic-inorganic composite antibacterial agent A (obtained in Preparation Example 1), and 3 parts of coupling agent KH-550 were uniformly mixed, and then melt-extruded, cast into a sheet, and after forming the sheet, bidirectional stretching, traction and winding were performed to obtain an antibacterial base film for dry film, and the thickness of the base film was 15 μm.

[0023] The melt-extrusion temperature was 305°C; the sheet casting temperature was 25°C; the lateral stretching ratio was 7, the longitudinal stretching ratio was 5.5, and the stretching temperature was 100°C, and the stretching rate was 120 mm / s.

[0024] Example 2 A method for preparing an antibacterial base film for dry film, comprising the following steps: By weight, 100 parts of PET resin (brand: CZ-333), 2 parts of antioxidant 168, 4 parts of lubricant calcium stearate, 15 parts of organic-inorganic composite antibacterial agent A (obtained in Preparation Example 1), and 5 parts of coupling agent KH-570 were uniformly mixed, and then melt-extruded, cast into a sheet, and after forming the sheet, bidirectional stretching, traction and winding were performed to obtain an antibacterial base film for dry film, and the thickness of the base film was 15 μm.

[0025] The melt-extrusion temperature was 305°C; the sheet casting temperature was 25°C; the lateral stretching ratio was 7, the longitudinal stretching ratio was 5.5, and the stretching temperature was 100°C, and the stretching rate was 120 mm / s.

[0026] Example 3 A method for preparing an antibacterial base film for dry film, comprising the following steps: ​Example 1 A base film for an antibacterial dry film was prepared by mixing 95 parts of PET resin (trade name: CZ-333), 1.5 parts of antioxidant 1076, 3 parts of lubricant pentaerythritol stearate, 12 parts of organic-inorganic composite antibacterial agent A (obtained in Preparation Example 1), and 3.5 parts of coupling agent KH-550 by weight, followed by melt extrusion, casting into a sheet, bidirectional stretching, and take-up.

[0027] The melt extrusion temperature was 305°C, the casting temperature was 25°C, the lateral stretching ratio was 7, the longitudinal stretching ratio was 5.5, the stretching temperature was 100°C, and the stretching rate was 120 mm / s.

[0028] Comparative Example 1 On the basis of Example 1, the organic-inorganic composite antibacterial agent A (obtained in Preparation Example 1) was replaced with polydopamine modified nano-ZnO (obtained in step S2 of Preparation Example 1), and the other operation steps and conditions were the same as in Example 1.

[0029] Comparative Example 2 On the basis of Example 1, the organic-inorganic composite antibacterial agent A (obtained in Preparation Example 1) was replaced with organic-inorganic composite antibacterial agent B (obtained in Preparation Example 2), and the other operation steps and conditions were the same as in Example 1.

[0030] Performance test The light transmittance, haze, thermal shrinkage, roughness, and antibacterial performance of the base films for antibacterial dry films of Examples 1-3 and Comparative Examples 1-2 were determined, and the test standards were as follows: 1) Light transmittance and haze: determined in accordance with the GB / T2410-2008 standard; 2) Longitudinal / Transverse Thermal Shrinkage: determined in accordance with the GB / T27584-2011 standard. Five sets of data were taken for each sample, and the sample size was 300 mm x 300 mm. The sample was placed in a 150°C oven for 2 hours, then cooled to room temperature to measure the size change in the MD (longitudinal) and TD (transverse) directions; 3) Surface roughness R a : determined in accordance with the GB / T1031-2009 standard; the surface roughness R a of the base film was measured using a VK-X160K tester, and five sets of data were taken for each sample, with the average value being taken; 4) Antibacterial performance test: determined in accordance with the GB / T31402-2023 standard for "Determination of Antibacterial Activity on the Surface of Plastics and Other Non-porous Materials".

[0031] The results are shown in Table 1.

[0032] Table 1 Performance test results

[0033] As shown in Table 1, the antibacterial dry film base film prepared by the present application has excellent product performance (high light transmittance, low heat shrinkage, low haze, low surface roughness, etc.) and antibacterial performance, and the antibacterial rate of Escherichia coli, Staphylococcus aureus and Candida albicans is as high as 99% or more. The main reason for achieving the above excellent effects may be that the polydopamine modified nano ZnO is obtained by polymerizing dopamine hydrochloride on the surface of zinc oxide nanoparticles, and then an antibacterial modifier containing a carboxyl group is used The polydopamine modified nano ZnO is modified to introduce triazole groups with high antibacterial activity, and the triazole groups can synergistically improve the antibacterial effect of the organic-inorganic composite antibacterial agent with zinc oxide and polydopamine.

[0034] The above examples are preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods, and are all included in the protection scope of the present application.

Claims

1. An antibacterial dry film base film, comprising, by weight, the following raw materials: 80-100 parts of PET resin 1-5 parts antioxidant 1-5 parts lubricant 1-5 parts of silane coupling agent 10-15 parts of organic-inorganic composite antibacterial agent The preparation method of the organic-inorganic composite antibacterial agent includes the following steps: Step S1: Add zinc acetate dihydrate and anhydrous ethanol to the reactor, stir evenly, then add KOH ethanol solution to react. After the reaction is completed, cool to room temperature, filter, and wash the filter cake with anhydrous ethanol and deionized water respectively. Vacuum dry the filter cake to obtain nano ZnO. Step S2: Add nano ZnO to Tris-buffer buffer, stir evenly, then add dopamine hydrochloride to react. After the reaction is complete, cool to room temperature, filter, wash the filter cake with deionized water, and vacuum dry the filter cake to obtain polydopamine modified nano ZnO. Step S3: Apply antibacterial modifier , N , N '-Carbonyl diimidazole and toluene were added to a reactor to obtain an activated antibacterial modifier; then polydopamine-modified nano-ZnO was added to react. After the reaction was completed, the mixture was allowed to stand and cool to room temperature, filtered, and the filter cake was washed with anhydrous ethanol and deionized water, respectively. The filter cake was then vacuum dried to obtain an organic-inorganic composite antibacterial agent.

2. The antibacterial dry film base film according to claim 1, characterized in that, The antioxidant is selected from one or more of antioxidant 168, antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 2246 and antioxidant BHT.

3. The antibacterial dry film base film according to claim 1, characterized in that, The lubricant is selected from one or more of N,N-ethylene bis-stearamide, calcium stearate, zinc stearate, and pentaerythritol stearate.

4. The antibacterial dry film base film according to claim 1, characterized in that, The coupling agent is selected from one or more of KH-550, KH-560, KH-570, KH-792, KH-791 and DL-602.

5. The antibacterial dry film base film according to claim 1, characterized in that, The mass ratio of nano-ZnO to dopamine hydrochloride is 1:(0.1~0.5); the antibacterial modifier and N , N The molar ratio of '-carbonyldiimidazole is 1:(1~1.5).

6. A method for preparing the antibacterial dry film base film according to any one of claims 1-5, comprising the following steps: By weight, PET resin, antioxidant, lubricant, organic-inorganic composite antibacterial agent and silane coupling agent are mixed evenly, and then melt extruded and cast into sheets to form a sheet. After biaxial stretching and traction winding, an antibacterial dry film base film is obtained.

7. The preparation method according to claim 6, characterized in that, The thickness of the base film used for the antibacterial dry film is 10~20μm.

8. The preparation method according to claim 6, characterized in that, The melt extrusion temperature is 270~310℃; the casting temperature is 20~40℃.

9. The preparation method according to claim 6, wherein the transverse stretching ratio is 5-8 and the longitudinal stretching ratio is 4-6 during biaxial stretching, the stretching temperature is 100-120℃, and the stretching rate is 100-130mm / s.

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