Antibacterial dry film base film and method for manufacturing the same

Abstract

The application belongs to the technical field of polyester film and specifically relates to an antibacterial dry film base film and a preparation method thereof.The base film comprises the following raw materials in parts by weight: PET resin 80-100 parts, antioxidant 1-5 parts, lubricant 1-5 parts, silane coupling agent 1-5 parts and organic-inorganic composite antibacterial agent 10-15 parts.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 base film to escherichia coli, staphylococcus aureus and candida albicans is as high as 99%.

Description

Technical Field

[0001] This invention belongs to the field of polyester film technology, specifically relating to an antibacterial dry film base film and its preparation method. Background Technology

[0002] Photosensitive dry film is widely used in electronics and printed circuit board (PCB) manufacturing. It plays a crucial role in PCB manufacturing by using ultraviolet light to trigger a polymerization reaction, generating a stable adhesive that adheres tightly to the copper plate surface. This effectively blocks electroplating, etching, and via masking, thus accurately transferring the PCB design circuitry onto the actual product. It typically consists of three layers: a polyester (PET) base film, a photoresist layer, and a polyethylene (PE) protective film. The PET base film, acting as a temporary carrier and physical support for the photoresist layer, plays a vital role in multiple stages, including coating, storage, transportation, exposure, and pre-development peeling. An ideal PET base film for dry film requires high light transmittance, excellent surface smoothness and cleanliness, good dimensional stability, suitable peelability, and moderate adhesion to the photoresist layer to ensure high precision and reliability of pattern transfer.

[0003] As the electronics and information industry develops towards higher density, higher precision, and higher reliability, and with the increasing diversity of production and storage environments, more stringent requirements are being placed on the stability of dry film and its components. However, during production, slitting, packaging, and storage, their surfaces may become contaminated with bacteria, mold, and other microorganisms from the environment or human contact. Under suitable temperature and humidity conditions, these microorganisms may proliferate on the base film surface or even migrate to the photoresist layer interface. Microbial contamination can pose multiple potential hazards to dry film quality and PCB manufacturing processes. For example, microbial colonies or metabolites may form physical defects, causing pattern flaws in subsequent exposures, leading to problems such as short circuits and open circuits. For dry film products requiring long-term warehousing or sea transport, the risk of microbial growth increases in humid environments, potentially causing unpredictable degradation of product performance over time.

[0004] Currently, commercially available conventional PET base films for dry film applications primarily focus on optimizing their optical, mechanical, and surface physical properties. This is achieved through methods such as raw material purification, nanoparticle addition, and surface coating modification to improve smoothness, reduce haze, and control peel force. However, these base films generally lack active antibacterial properties. While some high-end electronic materials fields implement strict microbial control in cleanroom environments, this involves external environmental management, is costly, and cannot completely eliminate the risk of secondary contamination in subsequent processes. Therefore, endowing PET base films with inherent antibacterial properties has become an inherent requirement for improving the overall reliability of dry film products, extending their shelf life, and adapting to a wider range of applications from the material source.

[0005] Therefore, developing a dry film base film that combines excellent optical and antibacterial properties has clear market demand and technological value for improving the quality reliability and environmental adaptability of high-end electronic manufacturing materials. Summary of the Invention

[0006] The main objective of this invention is to provide a base film for dry films that possesses both excellent optical and antibacterial properties. This invention will be achieved through the following technical solutions:

[0007] An antibacterial dry film base film, comprising, by weight, the following raw materials:

[0008] 80-100 parts of PET resin

[0009] 1-5 parts antioxidant

[0010] 1-5 parts lubricant

[0011] 1-5 parts of silane coupling agent

[0012] 10-15 parts of organic-inorganic composite antibacterial agent

[0013] The preparation method of the organic-inorganic composite antibacterial agent includes the following steps:

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] In some embodiments, the lubricant is selected from one or more of N,N-ethylene bis-stearamide, calcium stearate, zinc stearate, and pentaerythritol stearate.

[0019] 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.

[0020] In some implementations, 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).

[0021] The present invention also provides a method for preparing the base film for the above-mentioned antibacterial dry film, comprising the following steps:

[0022] 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.

[0023] In some embodiments, the thickness of the base film for the antibacterial dry film is 10~20μm.

[0024] In some implementations, the melt extrusion temperature is 270~310°C; the casting temperature is 20~40°C.

[0025] In some implementations, the transverse tensile ratio is 5-8 and the longitudinal tensile ratio is 4-6 during biaxial stretching, the stretching temperature is 100-120℃, and the stretching rate is 100-130 mm / s.

[0026] The present invention has achieved the following beneficial effects:

[0027] 1) The antibacterial dry film base film prepared by this invention has excellent product performance (high light transmittance, low heat shrinkage, low haze, low surface roughness, etc.) and antibacterial properties, with an antibacterial rate of over 99% against Escherichia coli, Staphylococcus aureus, and Candida albicans.

[0028] 2) This invention obtains polydopamine-modified nano-ZnO by polymerizing dopamine hydrochloride on the surface of zinc oxide nanoparticles, and then uses a carboxyl-containing antibacterial modifier. Polydopamine-modified nano-ZnO is modified to introduce triazole groups with high antibacterial activity. These triazole groups can synergistically enhance the antibacterial effect of the organic-inorganic composite antibacterial agent with zinc oxide and polydopamine. Detailed Implementation

[0029] Various exemplary embodiments of the present invention are now described in detail. This detailed description should not be considered as a limitation of the invention, but rather as a more detailed description of certain aspects, features, and embodiments of the invention. Furthermore, the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Additionally, for numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included within the scope of this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail. Furthermore, unless otherwise stated, all materials used in this invention are commercially available.

[0031] Preparation Example 1: Preparation of Organic-Inorganic Composite Antibacterial Agent A

[0032] Step S1: Add 5.0 g of zinc acetate dihydrate and 100 mL of anhydrous ethanol to a three-necked flask, heat to 75 °C and stir until homogeneous. Then slowly add 30 mL of a 2.5 mol / L KOH ethanol solution and continue stirring at 75 °C for 10 h. After the reaction is complete, allow to cool to room temperature, filter, and wash the filter cake three times with anhydrous ethanol and deionized water respectively. Dry the filter cake under vacuum at 100 °C for 12 h, then grind to obtain nano-ZnO.

[0033] Step S2: Add 5.0 g of nano-ZnO to 100 mL of Tris-buffer buffer at pH 8.5, stir well, then add 0.5 g of dopamine hydrochloride, heat to 50 °C and stir for 2 h. After the reaction is complete, allow to cool to room temperature, filter, wash the filter cake three times with deionized water, and vacuum dry at 100 °C for 10 h to obtain polydopamine-modified nano-ZnO.

[0034] Step S3: Apply antibacterial modifier (0.1 mol) N , N0.1 mol of '-carbonyl diimidazole (CDI) and 200 mL of toluene were added to a three-necked flask, and the mixture was heated to 70 °C and stirred for 2 h to obtain an antibacterial modifier activated by CDI. Then, 10.0 g of polydopamine-modified nano-ZnO was added, and the mixture was sonicated for 0.5 h. Finally, the mixture was stirred at 70 °C for another 5 h. After the reaction was complete, the mixture was allowed to cool to room temperature, filtered, and the filter cake was washed three times with anhydrous ethanol and deionized water, respectively. The filter cake was then vacuum dried at 100 °C for 12 h to obtain organic-inorganic composite antibacterial agent A.

[0035] Preparation Example 2: Preparation of Organic-Inorganic Composite Antibacterial Agent B

[0036] Based on Preparation Example 1, the antibacterial modifier in step S3 was added. Replace with Other operating steps and conditions are the same as in Preparation Example 1, to obtain organic-inorganic composite antibacterial agent B.

[0037] Example 1: A method for preparing a base film for an antibacterial dry film, comprising the following steps:

[0038] By weight, 90 parts of PET resin (brand: CZ-333), 3 parts of antioxidant 1010, 2 parts of lubricant N,N-ethylene bis-stearamide, 10 parts of organic-inorganic composite antibacterial agent A (obtained in Preparation Example 1), and 3 parts of coupling agent KH-550 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 with a thickness of 15 μm is obtained.

[0039] The melt extrusion temperature is 305℃; the casting temperature is 25℃; the transverse stretching ratio is 7 and the longitudinal stretching ratio is 5.5 during biaxial stretching, the stretching temperature is 100℃, and the stretching rate is 120mm / s.

[0040] Example 2: A method for preparing a base film for an antibacterial dry film, comprising the following steps:

[0041] 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 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 with a thickness of 15 μm is obtained.

[0042] The melt extrusion temperature is 305℃; the casting temperature is 25℃; the transverse stretching ratio is 7 and the longitudinal stretching ratio is 5.5 during biaxial stretching, the stretching temperature is 100℃, and the stretching rate is 120mm / s.

[0043] Example 3: A method for preparing a base film for an antibacterial dry film, comprising the following steps:

[0044] By weight, 95 parts of PET resin (brand: 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 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 with a thickness of 15 μm is obtained.

[0045] The melt extrusion temperature is 305℃; the casting temperature is 25℃; the transverse stretching ratio is 7 and the longitudinal stretching ratio is 5.5 during biaxial stretching, the stretching temperature is 100℃, and the stretching rate is 120mm / s.

[0046] Comparative Example 1

[0047] Based on 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 other operating steps and conditions were the same as in Example 1.

[0048] Comparative Example 2

[0049] Based on 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 other operating steps and conditions were the same as in Example 1.

[0050] Performance testing

[0051] The transmittance, haze, thermal shrinkage, roughness, and antibacterial properties of the base films used for the antibacterial dry films of Examples 1-3 and Comparative Examples 1-2 were measured according to the following standards:

[0052] 1) Light transmittance and haze: measured in accordance with GB / T2410-2008 standard;

[0053] 2) Longitudinal / transverse heat shrinkage rate: The measurement was performed according to the standard GB / T27584-2011. Five sets of data were collected for each sample. The sample size was 300mm x 300mm. The samples were placed in an oven at 150℃ and cooled to room temperature for 2 hours before measuring the dimensional changes of MD (longitudinal) and TD (transverse).

[0054] 3) Surface roughness R a The determination was carried out in accordance with GB / T1031-2009 standard; the surface roughness R of the base film was tested using a VK-X160K tester. a Five sets of data were taken for each sample, and the average value was calculated.

[0055] 4) Antibacterial performance test: The test shall be conducted in accordance with the standard GB / T31402-2023 "Determination of antibacterial activity of plastics and other non-porous materials".

[0056] The results are shown in Table 1.

[0057] Table 1 Performance Test Results

[0058]

[0059] As shown in Table 1, the antibacterial dry film base film prepared by this invention possesses excellent product performance (high light transmittance, low thermal shrinkage, low haze, low surface roughness, etc.) and antibacterial properties, with an antibacterial rate of over 99% against Escherichia coli, Staphylococcus aureus, and Candida albicans. The main reason for achieving these excellent results may be that this invention obtains polydopamine-modified nano-ZnO by polymerizing dopamine hydrochloride on the surface of zinc oxide nanoparticles, and then uses a carboxyl-containing antibacterial modifier. Polydopamine-modified nano-ZnO is modified to introduce triazole groups with high antibacterial activity. These triazole groups can synergistically enhance the antibacterial effect of the organic-inorganic composite antibacterial agent with zinc oxide and polydopamine.

[0060] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A base film for antibacterial dry film, comprising the following raw materials in parts 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, 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, and the filter cake is vacuum dried to obtain nano ZnO; Step S2: nano ZnO is added to Tris-buffer buffer solution, stirred uniformly, then dopamine hydrochloride is added for reaction, after the reaction is completed, it is cooled to room temperature, filtered, the filter cake is washed with deionized water, and the filter cake is vacuum dried to obtain polydopamine modified nano ZnO; Step S3: adding an antibacterial modifier , N , N carbonyl diimidazole and toluene into the reactor to obtain an activated antibacterial modifier; then adding polydopamine modified nano-ZnO for reaction, after the reaction, standing and cooling to room temperature, suction filtration, and washing the filter cake with anhydrous ethanol and deionized water respectively, vacuum drying the filter cake to obtain an organic-inorganic composite antibacterial agent.

2. The antibacterial dry film base film according to claim 1, characterized by 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 base film for a dry film according to claim 1, characterized by The lubricant is selected from one or more of N,N-ethylene bis-hydroxystearic acid amide, calcium stearate, zinc stearate and pentaerythritol stearate.

4. The antibacterial base film for a dry film according to claim 1, characterized by The silane 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 by 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 preparation method of the base film for antibacterial dry film according to any one of claims 1-5, comprising the following steps: The PET resin, antioxidant, lubricant, organic-inorganic composite antibacterial agent and silane coupling agent are mixed uniformly in parts by weight, then melt extruded, cast into a sheet, after the sheet is bidirectionally stretched and drawn, the antibacterial dry film base film is obtained.

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

8. The preparation method according to claim 6, characterized in that, The melt extrusion temperature is 270-310℃; the sheet casting temperature is 20-40℃. 9.The preparation method according to claim 6, wherein the lateral stretching ratio is 5-8, the longitudinal stretching ratio is 4-6, the stretching temperature is 100-120℃, and the stretching rate is 100-130 mm / s.

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