Modified PBT release film and preparation method thereof

Abstract

The invention discloses a modified PBT release film which comprises a film body, the film body comprises a first film layer, a second film layer and a third film layer which are sequentially arranged, both the first film layer and the third film layer are modified high-temperature-resistant PBT film layers, and the second film layer is a modified toughened PBT film layer. The invention also discloses a preparation method of the modified PBT release film. According to the invention, the first layer of film and the third layer of film are release layers prepared by adding a nano cage-like polysilsesquioxane (POSS) silicon-based material with good release property and temperature and scratch resistance, a flexibilizer ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA) and an antioxidant into a PBT resin matrix; the middle layer is made of an EMA and antioxidant modified PBT material, the three-layer structure can improve the overall mechanical property, the first layer and the third layer can be well fused together, and the prepared release film is good in release property and free of layering.

Description

Technical Field

[0001] The present invention relates to the field of release films, and in particular to a method for preparing a modified PBT release film. Background Art

[0002] High-temperature-resistant, adhesive-resistant release film was first developed by Sekisui Co., Ltd. in Japan. This process involves co-extruding a five-layer composite of TPX (poly-4-methylpentene-1) film from raw materials from Mitsui and Sumitomo. The outer two layers consist of TPX film, with a central layer of PE film. This film is primarily used for lamination of flexible printed circuits (FPCs). Due to the high price of TPX particles, which is monopolized by Mitsui Co., Ltd., and the indispensability of heat-resistant release films, the development of new high-temperature-resistant release film products is becoming increasingly important.

[0003] Currently, release films based on PBT (polybutylene terephthalate) are available on the market, but they often suffer from poor release properties and limited adhesive resistance. Furthermore, due to PBT's inherently low glass transition temperature, its temperature resistance is insufficient for use in high-temperature or harsh environments. Therefore, there is an urgent need to develop a release film with excellent high-temperature resistance and release properties that can meet the requirements of flexible circuit board (FPC) lamination and improve the yield rate of flexible circuit boards. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a modified PBT release film.

[0005] The innovation of the present invention lies in that the first and third layers of the film are release layers made by adding nano-cage polysilsesquioxane (POSS) silicon-based materials with good release properties and heat resistance and scratch resistance, toughening agent ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA), and antioxidant into a PBT resin matrix, and the middle layer is a PBT material modified with EMA and an antioxidant. Such a three-layer structure can not only improve the overall mechanical properties, but also enable the first and third layers to be well integrated together, so that the prepared release film has good release properties and does not delaminate.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution of the present invention is:

[0007] A modified PBT release film, wherein the film body comprises a first film layer, a second film layer and a third film layer arranged in sequence, the first film layer and the third film layer are both modified high-temperature resistant PBT film layers, and the second film layer is a modified toughened PBT film layer.

[0008] Furthermore, the thickness of the membrane body is 100-150 μm, the thickness of the first membrane layer is equal to that of the third membrane layer, and the thickness ratio of the first membrane layer to the second membrane layer is 1:3-5.

[0009] Furthermore, the modified high-temperature resistant PBT film layer is obtained by mixing PBT particles, nano-cage polysilsesquioxane and antioxidant, extruding and granulating the mixture, and then extruding the mixture through a first main machine.

[0010] Furthermore, the nano caged polysilsesquioxane includes one or more of alkenyl caged polysilsesquioxane, epoxy caged polysilsesquioxane, amino caged polysilsesquioxane, and ester caged polysilsesquioxane.

[0011] A method for preparing a modified PBT release film, characterized in that:

[0012] (1) pouring the raw materials of the high temperature resistant layer modified masterbatch into a blender and stirring and mixing them uniformly to obtain a modified mixture, and then putting the modified mixture into a twin-screw extruder for granulation to obtain the high temperature resistant layer modified masterbatch, wherein the raw materials of the high temperature resistant layer modified masterbatch include PBT particles, nanocage polysilsesquioxane, and an antioxidant;

[0013] (2) The toughening layer modified masterbatch containing pure PBT and toughening agent powder is granulated, wherein the mass fraction of pure PBT is 90-99.5wt% and the mass fraction of toughening agent is

[0014] 0.5~10wt%;

[0015] (3) The modified masterbatch of the high temperature resistant layer is placed in the first main machine, and the modified masterbatch of the toughening layer is placed in the second main machine, and the PBT release film is prepared by three-layer co-extrusion. The first layer of film and the third layer of film are extruded from the first main machine, and the film extruded from the first main machine is a modified high temperature resistant PBT film layer. The second layer of film is extruded from the second main machine, and the film extruded from the second main machine is a modified toughened PBT film layer.

[0016] Furthermore, in the step (1), the mass fraction of the PBT particles is 75-97.9 wt%, the mass fraction of the nano-cage polysilsesquioxane is 2-20 wt%, and the mass fraction of the antioxidant is 0.1-5 wt%.

[0017] Furthermore, the toughening agent is ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA).

[0018] The beneficial effects of the present invention are:

[0019] 1. In the present invention, PBT particles are modified by using nano-cage polysilsesquioxane (POSS), a toughening agent (ethylene-methyl acrylate-glycidyl methacrylate terpolymer, EMA), and an antioxidant to improve the mechanical properties of the PBT particles. The interaction between the nano-cage polysilsesquioxane (POSS), the toughening agent, and the antioxidant improves the thermal stability of the formed modified PBT film while maintaining the optical properties of the polymer product, thereby preparing the PBT release film with high temperature resistance, good stability, and good release properties.

[0020] 2. The first and third layers of the film in the present invention are release layers made by adding nano-cage polysilsesquioxane (POSS) silicon-based materials with good release properties and heat resistance and scratch resistance, toughening agent ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA), and antioxidant into the PBT resin matrix. The middle layer is a PBT material modified by ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA) and antioxidant. Such a three-layer structure can not only improve the overall mechanical properties, but also enable the first and third layers to be well integrated together, so that the prepared release film has good release properties and does not delaminate.

[0021] 3. The modified PBT release film of the present invention has good release effect and good temperature resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of the monomer structure of nanocage-like polysilsesquioxane (POSS); DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings.

[0024] Example 1: A modified PBT release film comprises a film body comprising a first, second, and third film layers arranged in sequence. The first and third film layers are modified high-temperature-resistant PBT film layers, and the second film layer is a modified toughened PBT film layer. The film body has a thickness of 100-150 μm, the first and third film layers are equal in thickness, and the thickness ratio of the first to second film layers is 1:3.

[0025] The modified high-temperature resistant PBT film layer is obtained by mixing PBT particles, nano-cage polysilsesquioxane, a toughening agent and an antioxidant, extruding granulation and then extruding through a first main machine. The nano-cage polysilsesquioxane is an alkenyl cage polysilsesquioxane.

[0026] Example 2: Referring to Example 1, the nano caged polysilsesquioxane is one or more of alkenyl caged polysilsesquioxane, epoxy caged polysilsesquioxane, amino caged polysilsesquioxane, and ester caged polysilsesquioxane; the thickness ratio of the first film layer to the second film layer is 1:4 or 5.

[0027] Example 3: A method for preparing a modified PBT release film.

[0028] (1) pouring the raw materials of the high-temperature resistant layer modified masterbatch into a blender and stirring and mixing them uniformly to obtain a modified mixture, and then putting the modified mixture into a twin-screw extruder for granulation to obtain the high-temperature resistant layer modified masterbatch, wherein the raw materials of the high-temperature resistant layer modified masterbatch include PBT particles, nano-cage polysilsesquioxane, and an antioxidant, wherein the mass fraction of the PBT particles is 75wt%, the mass fraction of the nano-cage polysilsesquioxane is 20wt%, and the mass fraction of the antioxidant is 5wt%; the nano-cage polysilsesquioxane is an alkenyl cage polysilsesquioxane;

[0029] (2) A toughening layer modified masterbatch is obtained by granulating pure PBT and toughening agent powder, wherein the mass fraction of pure PBT is 90 wt% and the mass fraction of toughening agent is 10 wt%; the toughening agent is ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA).

[0030] (3) The modified masterbatch of the high temperature resistant layer is placed in the first main machine, and the modified masterbatch of the toughening layer is placed in the second main machine, and the PBT release film is prepared by three-layer co-extrusion. The first layer of film and the third layer of film are extruded from the first main machine, and the film extruded from the first main machine is a modified high temperature resistant PBT film layer. The second layer of film is extruded from the second main machine, and the film extruded from the second main machine is a modified toughened PBT film layer.

[0031] Example 4: A method for preparing a modified PBT release film.

[0032] (1) pouring the raw materials of the high-temperature resistant layer modified masterbatch into a blender and stirring and mixing them uniformly to obtain a modified mixture, and then putting the modified mixture into a twin-screw extruder for granulation to obtain the high-temperature resistant layer modified masterbatch, wherein the raw materials of the high-temperature resistant layer modified masterbatch include PBT particles, nano-cage polysilsesquioxane, and an antioxidant, wherein the mass fraction of the PBT particles is 97.9wt%, the mass fraction of the nano-cage polysilsesquioxane is 2wt%, and the mass fraction of the antioxidant is 0.1wt%; the nano-cage polysilsesquioxane is an epoxy cage polysilsesquioxane;

[0033] (2) granulating pure PBT and toughening agent powder to obtain a toughening layer modified masterbatch, wherein the pure PBT content is 95 wt% and the toughening agent content is 5 wt%;

[0034] (3) The modified masterbatch of the high temperature resistant layer is placed in the first main machine, and the modified masterbatch of the toughening layer is placed in the second main machine, and the PBT release film is prepared by three-layer co-extrusion. The first layer of film and the third layer of film are extruded from the first main machine, and the film extruded from the first main machine is a modified high temperature resistant PBT film layer. The second layer of film is extruded from the second main machine, and the film extruded from the second main machine is a modified toughened PBT film layer.

[0035] Example 5: A method for preparing a modified PBT release film.

[0036] (1) pouring the raw materials of the high-temperature resistant layer modified masterbatch into a blender and stirring and mixing them uniformly to obtain a modified mixture, and then putting the modified mixture into a twin-screw extruder for granulation to obtain the high-temperature resistant layer modified masterbatch, wherein the raw materials of the high-temperature resistant layer modified masterbatch include PBT particles, nano-cage polysilsesquioxane, and an antioxidant, wherein the mass fraction of the PBT particles is 85wt%, the mass fraction of the nano-cage polysilsesquioxane is 12wt%, and the mass fraction of the antioxidant is 3wt%; the nano-cage polysilsesquioxane is amino-cage polysilsesquioxane;

[0037] (2) granulating pure PBT and toughening agent powder to obtain a toughening layer modified masterbatch, wherein the pure PBT content is 99.5wt% and the toughening agent content is 0.5wt%;

[0038] (3) The modified masterbatch of the high temperature resistant layer is placed in the first main machine, and the modified masterbatch of the toughening layer is placed in the second main machine, and the PBT release film is prepared by three-layer co-extrusion. The first layer of film and the third layer of film are extruded from the first main machine, and the film extruded from the first main machine is a modified high temperature resistant PBT film layer. The second layer of film is extruded from the second main machine, and the film extruded from the second main machine is a modified toughened PBT film layer.

[0039] Comparative Example 1: Referring to Example 3, the mass fraction of nano-cage polysilsesquioxane is 4.9 wt % and is replaced by PBT particles.

[0040] Comparative Example 2: Referring to Example 3, the nanocage-like polysilsesquioxane and the antioxidant were replaced with PBT particles.

[0041] Evaluation method: Mold release evaluation: overlap the release film on a stainless steel plate with a smooth surface and press it at 180°C and 30 kgf / cm 2 Then, cut into 50mm x 30mm x 50mm in length and width and conduct peel test at a test speed of 500mm / min and a peel angle of 180°. 2 The following cases are marked as √, which will exceed 20gf / cm 2 The case is set to ×.

[0042] Thermal stability evaluation: The thermal decomposition temperature (Td5％ ),

[0043] Evaluation of resin exudation: Cut the release film into 10×10 cm squares and heat press it using a sliding vacuum heater press. Measure the distance between the end of the resin constituting the cushion layer that has exuded from the release film and the end of the release layer of the release film as the exudation distance. If the exudation distance is less than 1 mm, it is set as √. If it is more than 1 mm and less than 2 mm, it is set as The case exceeding 2 mm was marked as ×.

[0044]

[0045] The above analysis results indicate that modified PBT release films obtained by adding nanocage-like polysilsesquioxane (POSS) to PBT film through tape casting and multilayer coextrusion exhibit better high-temperature resistance and release properties than pure PBT release films. This is because the introduction of nanocage-like polysilsesquioxane reduces the film's surface tension, and its high glass transition temperature simultaneously improves the thermal stability of the PBT release film. This results in a PBT release film that exhibits high-temperature resistance, excellent release and adhesive resistance, and maintains excellent optical properties. This allows for better application in flexible circuit board lamination, expanding its application in the FPC electronics field.

[0046] The embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

Claims

1. A modified PBT release film, comprising a film body, characterized in that: The membrane body comprises a first membrane layer, a second membrane layer and a third membrane layer which are arranged in sequence. The first membrane layer and the third membrane layer are both modified high-temperature resistant PBT membrane layers, and the second membrane layer is a modified toughened PBT membrane layer.

2. The modified PBT release film according to claim 1, characterized in that The thickness of the membrane body is 100-150 μm, the thickness of the first membrane layer is equal to that of the third membrane layer, and the thickness ratio of the first membrane layer to the second membrane layer is 1:3-5.

3. The modified PBT release film according to claim 1, characterized in that: The modified high-temperature resistant PBT film layer is obtained by mixing PBT particles, nano-cage-shaped polysilsesquioxane and an antioxidant, extruding the mixture into granules, and then extruding the mixture through a first main machine.

4. The modified PBT release film according to claim 1, characterized in that The nano caged polysilsesquioxane includes one or more of alkenyl caged polysilsesquioxane, epoxy caged polysilsesquioxane, amino caged polysilsesquioxane, and ester caged polysilsesquioxane.

5. A method for preparing the modified PBT release film according to any one of claims 1 to 4, characterized in that: (1) Pour the raw materials of the high temperature resistant layer modified masterbatch into a blender and stir and mix them evenly to obtain a modified mixture, and then put the modified mixture into a twin-screw extruder for granulation to obtain the high temperature resistant layer modified masterbatch, wherein the raw materials of the high temperature resistant layer modified masterbatch include PBT particles, nanocage polysilsesquioxane, and antioxidant; (2) The toughening layer modified masterbatch containing pure PBT and toughening agent powder is granulated, wherein the mass fraction of pure PBT is 90~99.5wt% and the mass fraction of toughening agent is 0.5~10wt%; (3) The modified masterbatch of the high temperature resistant layer is placed in the first main machine, and the modified masterbatch of the toughening layer is placed in the second main machine. The PBT release film is prepared by three-layer co-extrusion. The first layer of film and the third layer of film are extruded from the first main machine. The film extruded from the first main machine is a modified high temperature resistant PBT film layer. The second layer of film is extruded from the second main machine. The film extruded from the second main machine is a modified toughened PBT film layer.

6. The method for preparing the modified PBT release film according to claim 3, wherein: In the step (1), the mass fraction of PBT particles is 75-97.9 wt%, the mass fraction of nano-cage polysilsesquioxane is 2-20 wt%, and the mass fraction of antioxidant is 0.1-5 wt%.

7. The method for preparing the modified PBT release film according to claim 3, wherein: The toughening agent is ethylene-methyl acrylate-glycidyl methacrylate terpolymer (EMA).

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