An ultrathin optical grade polyester-based film

Abstract

The utility model discloses a kind of ultra-thin optical grade polyester base films, including at least five layers of co-extrusion composite structure, from outside to inside in turn are: first skin, including optical grade polyester chip and antistatic agent;First adhesive layer, including optical grade polyester chip and tackifying masterbatch;Core layer, by pure optical grade polyester chip is formed;Second adhesive layer, with first adhesive layer symmetry;Second skin, with first skin symmetry;The base film surface has the release coating of on-line coating.The utility model passes through five layers structure design, balances mechanical property and optical property;On-line coating integration process reduces pollution, reduces energy consumption;Release force adjustable (5~15g / in), adapts to the diversification demand of electronic field.

Description

Technical Field

[0001] This utility model relates to the field of polymer materials technology, specifically an ultrathin optical-grade polyester film. Background Technology

[0002] Currently, the release protective films commonly used in the electronics field mainly adopt the following two technical routes:

[0003] Combining single-layer polyester film with offline coating: After preparing a single-layer PET film through biaxial stretching, a silicone release agent is applied using an offline coating process. This technology has the following drawbacks: low light transmittance (typically ≤88%), resulting in deterioration of optical performance due to solvent residue and multiple processing steps; poor release force stability (fluctuation range ±2g / in or more), affecting the accuracy of electronic component bonding; and cumbersome process, requiring slitting and secondary processing, increasing energy consumption by more than 30%.

[0004] Three-layer co-extruded film:

[0005] While the surface / core / surface structure improves mechanical properties, it has several drawbacks: the lack of a functional adhesive layer results in insufficient bonding strength with the adhesive (peel force < 0.5 N / 25 mm); and the absence of an integrated online coating design makes it difficult to meet electronic-grade surface cleanliness requirements (particle contamination ≥ 50 particles / m²). 2 ). Summary of the Invention

[0006] The purpose of this invention is to provide an ultra-thin optical-grade polyester film suitable for release protection applications in display manufacturing, optical tape and flexible circuit board processing.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] An ultrathin optical-grade polyester base film is characterized by comprising at least five co-extruded composite layers, which, from the outside to the inside, are: a first surface layer comprising optical-grade polyester chips and an antistatic agent; a first adhesive layer comprising optical-grade polyester chips and an tackifying masterbatch; a core layer composed of pure optical-grade polyester chips; a second adhesive layer symmetrical to the first adhesive layer; and a second surface layer symmetrical to the first surface layer; wherein the base film surface has an online-coated release coating.

[0009] The present invention further provides that the release coating comprises acrylate resin, silicone release agent and nano-SiO2, wherein the particle size of nano-SiO2 is 10-50nm and accounts for 0.5-3% of the total mass of the coating.

[0010] The present invention further comprises that the tackifying masterbatch is maleic anhydride grafted modified polyester, which has a mass fraction of 1-5% in the first adhesive layer or the second adhesive layer and a grafting rate of 0.8-1.5%.

[0011] The present invention further comprises a core layer having a thickness of 50-70% of the total thickness of the base film and a density of 1.38-1.40 g / cm³. 3 Its intrinsic viscosity is 0.65±0.02 dL / g.

[0012] The present invention further provides that the antistatic agent is a permanent antistatic agent selected from polyether ester amide or quaternary ammonium salt compounds, and its mass fraction in the first or second surface layer is 0.5-2%.

[0013] The present invention further provides that the surface roughness of the release coating is ≤0.01μm and the coating thickness is 0.5~1.2μm.

[0014] The present invention further provides that the total thickness of the base film is 25-150 μm, the light transmittance is ≥90%, the haze is ≤1.0%, and the surface tension is ≥50 dyn / cm.

[0015] The present invention further provides that the longitudinal tensile strength of the base film is ≥150MPa, the transverse tensile strength is ≥130MPa, and the heat shrinkage rate is ≤1.5%.

[0016] The present invention further provides that the release force of the release coating is 5 to 15 g / in, and the release force fluctuation range is ≤ ±1 g / in.

[0017] The present invention further includes a corona treatment layer in the base film, which is disposed between the release coating and the surface layer, with a corona treatment power of 5 to 15 kW and a treatment speed of 10 to 30 m / min.

[0018] The beneficial effects of this utility model are: the five-layer structure design balances mechanical and optical properties; the online coating integrated process reduces pollution and energy consumption; and the release force is adjustable (5-15g / in) to meet the diverse needs of the electronics field. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0020] Figure 1 This is a schematic diagram of the structure of the polyester-based film of this utility model.

[0021] Reference numerals: 10, first surface layer; 20, first adhesive layer; 30, core layer; 40, second adhesive layer; 50, second surface layer of the present invention; Detailed Implementation

[0022] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0023] This invention provides an ultrathin optical-grade polyester film comprising at least five co-extruded composite layers, from the outside to the inside: a first surface layer comprising optical-grade polyester chips and an antistatic agent; a first adhesive layer comprising optical-grade polyester chips and an tackifying masterbatch; a core layer composed of pure optical-grade polyester chips; a second adhesive layer symmetrical to the first adhesive layer; and a second surface layer symmetrical to the first surface layer; the surface of the film has an online-coated release coating.

[0024] The present invention further provides that the release coating comprises acrylate resin, silicone release agent and nano-SiO2, wherein the particle size of nano-SiO2 is 10-50nm and accounts for 0.5-3% of the total mass of the coating.

[0025] The present invention further comprises that the tackifying masterbatch is maleic anhydride grafted modified polyester, which has a mass fraction of 1-5% in the first adhesive layer or the second adhesive layer and a grafting rate of 0.8-1.5%.

[0026] The present invention further comprises a core layer having a thickness of 50-70% of the total thickness of the base film and a density of 1.38-1.40 g / cm³. 3 Its intrinsic viscosity is 0.65±0.02 dL / g.

[0027] The present invention further provides that the antistatic agent is a permanent antistatic agent selected from polyether ester amide or quaternary ammonium salt compounds, and its mass fraction in the first or second surface layer is 0.5-2%.

[0028] The present invention further provides that the surface roughness of the release coating is ≤0.01μm and the coating thickness is 0.5~1.2μm.

[0029] The present invention further provides that the total thickness of the base film is 25-150 μm, the light transmittance is ≥90%, the haze is ≤1.0%, and the surface tension is ≥50 dyn / cm.

[0030] The present invention further provides that the longitudinal tensile strength of the base film is ≥150MPa, the transverse tensile strength is ≥130MPa, and the heat shrinkage rate is ≤1.5%.

[0031] The present invention further provides that the release force of the release coating is 5 to 15 g / in, and the release force fluctuation range is ≤ ±1 g / in.

[0032] The present invention further includes a corona treatment layer in the base film, which is disposed between the release coating and the surface layer, with a corona treatment power of 5 to 15 kW and a treatment speed of 10 to 30 m / min.

[0033] The beneficial effects of this utility model are: the five-layer structure design balances mechanical and optical properties; the online coating integrated process reduces pollution and energy consumption; and the release force is adjustable (5-15g / in) to meet the diverse needs of the electronics field.

[0034] The specific embodiments are now described in detail:

[0035] Example 1:

[0036] High-transmittance release protective film

[0037] 1. Raw material formula

[0038] Layer A (surface layer): Optical grade PET chips (intrinsic viscosity 0.65 dL / g) + 1.5% polyether ester amide antistatic agent

[0039] Layer B (adhesive layer): Optical grade PET chips + 3% maleic anhydride grafted modified polyester (grafting rate 1.2%)

[0040] Layer C (core layer): Pure optical-grade PET slices (density 1.39 g / cm³) 3 )

[0041] Release coating: Acrylic resin (60wt%), silicone release agent (30wt%), nano-SiO2 (2wt%, particle size 30nm), ethyl acetate (8wt%)

[0042] 2. Preparation process:

[0043] Co-extrusion parameters:

[0044] Layer A: 265℃ | Layer B: 270℃ | Layer C: 275℃

[0045] Die head pressure 18MPa, melt pump metering error ±0.3%.

[0046] Stretching process:

[0047] Longitudinal (MD): 3.5x, 100℃ | Transverse (TD): 3.8x, 110℃ Coating and Curing:

[0048] Microgravure coating amount: 3.0 g / m 2 Coating speed 30m / min, UV curing energy 500mJ / cm 2 (wavelength 365nm)

[0049] Post-processing: Corona treatment power 12kW, speed 25m / min

[0050] 3. Performance Test Results

[0051]

[0052] Example 2: High antistatic release protective film

[0053] 1. Improved raw materials (Layer A): Increase antistatic agent to 2% (quaternary ammonium salt).

[0054] Release coating: Adding 0.5% carbon nanotubes (CNTs) enhances antistatic properties. 2. Key process adjustments increase corona treatment power to 15kW.

[0055] Infrared drying (80℃, 10s) is added after coating.

[0056] 3. Performance Comparison

[0057]

[0058]

[0059] Example 3: Ultrathin (25μm) base film

[0060] 1. Structural optimization

[0061] Thickness distribution: Layer A 5μm | Layer B 3μm | Layer C 12μm | Layer B 3μm | Layer A 5μm Coating weight: Reduced to 2.5g / m2 (coating thickness 0.8μm)

[0062] 2. Process Challenges and Solutions

[0063] Problem: Thin layers are prone to uneven stretching

[0064] improve:

[0065] A synchronous stretching machine is used (MD / TD synchronization error ≤1%).

[0066] The temperature of the cooling roller is accurate to ±0.5℃.

[0067] 3. Performance Data

[0068]

[0069] Comparative Example 1 (Traditional Offline Coating Process)

[0070] Method: Co-extruded film is first slit and then coated offline. Defects: Light transmittance is reduced to 88.5% (caused by solvent residue), and release force fluctuates by ±2g / in. Example 4: High temperature resistant base film (suitable for FPC process).

[0071] 1. Material improvement

[0072] Layer C: Added 0.1% nano Al2O3 (to improve temperature resistance)

[0073] Release coating: Changed to high-temperature resistant silicone resin (withstands 230℃)

[0074] 2. High Temperature Test Results

[0075]

[0076] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0077] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes that element.

[0078] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept by means of the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. An ultrathin optical-grade polyester-based film, characterized in that, It comprises at least five co-extruded composite structures, from the outside to the inside as follows: a first surface layer containing optical-grade polyester chips and an antistatic agent; a first adhesive layer containing optical-grade polyester chips and a tackifying masterbatch; a core layer composed of pure optical-grade polyester chips; a second adhesive layer symmetrical to the first adhesive layer; a second surface layer symmetrical to the first surface layer; and the base film surface has an online-coated release coating.

2. The ultrathin optical-grade polyester film according to claim 1, characterized in that, The core layer accounts for 50-70% of the total thickness of the base film, has a density of 1.38-1.40 g / cm³, and an intrinsic viscosity of 0.65±0.02 dL / g.

3. The ultrathin optical-grade polyester film according to claim 1, characterized in that, The surface roughness of the release coating is ≤0.01 μm, and the coating thickness is 0.5~1.2 μm.

4. The ultrathin optical-grade polyester film according to claim 1, characterized in that, The base film has a total thickness of 25~150 μm, a light transmittance of ≥90%, a haze of ≤1.0%, and a surface tension of ≥50 dyn / cm.

5. The ultrathin optical-grade polyester film according to claim 1, characterized in that, The base film has a longitudinal tensile strength ≥150 MPa, a transverse tensile strength ≥130 MPa, and a heat shrinkage rate ≤1.5%.

6. The ultrathin optical-grade polyester film according to claim 1, characterized in that, The release force of the release coating is 5~15 g / in, and the release force fluctuation range is ≤±1 g / in.

7. The ultrathin optical-grade polyester film according to claim 1, characterized in that, The base film also includes a corona treatment layer disposed between the release coating and the surface layer, with a corona treatment power of 5~15 kW and a treatment speed of 10~30 m / min.

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