A PVD process protective film and preparation method thereof

Abstract

The present invention relates to a PVD process protective film and a preparation method thereof. The PVD process protective film comprises a coating layer, a PET substrate layer, an acrylate adhesive layer and a non-silicon release film layer. The PVD process protective film of the present invention adds a coating layer to the PET protective film, thereby playing a role in supporting the protective film, reducing deformation of the protective film, controlling the expansion and contraction rate, and preventing undesirable conditions such as overflow plating in the PVD process.

Description

Technical Field

[0001] The present invention belongs to the technical field of protective films, and in particular, relates to a PVD process protective film and a preparation method thereof. Background Art

[0002] The PVD process of mobile phone glass requires a relatively high temperature and vacuum degree, generally baking at 160℃-180℃ for 2-3 hours. The performance requirements for the protective film are getting higher and higher, requiring the protective film to not wrinkle and have a small expansion and contraction rate. The existing high-temperature resistant PVD process protective film has a large deformation due to high temperature conditions, which often causes quality problems such as overflow plating and lack of plating in the PVD process.

[0003] There is an urgent need to develop a PVD process protective film for mobile phone glass that will not cause quality problems such as over-plating and under-plating. Summary of the invention

[0004] In view of the above-mentioned defects of the prior art, the present invention provides a PVD process protective film for mobile phone glass which does not cause quality problems such as over-plating and under-plating, and a preparation method thereof.

[0005] The technical objectives of the present invention are achieved through the following technical solutions:

[0006] The invention provides a PVD process protective film, which comprises a coating layer, a PET substrate layer, an acrylate adhesive layer and a non-silicon release film layer.

[0007] Furthermore, the coating layer of the present invention comprises the following raw material components by weight: 80-100 parts of hydroxy acrylic resin, 5-20 parts of coating layer curing agent, 1-15 parts of gas silica, and 0.1-1.0 parts of leveling agent.

[0008] Furthermore, the hydroxy acrylic resin of the present invention has a Tg value of 40-60° C., a solid content of 50-60%, a viscosity of 7000-10000 mPa.s / 25° C., and a hydroxyl value of 10-100 mgKOH / g.

[0009] Furthermore, the coating layer curing agent of the present invention is selected from HDI or TDI type closed curing agent, which has good flexibility and chemically crosslinks with acrylic resin after heating and unsealing (unsealing temperature>95°C), thereby increasing adhesion to the PET film; preferably, the coating layer curing agent is selected from Bayer BL3175.

[0010] Furthermore, the gas silica of the present invention is selected from hydrophobic fumed silica; preferably, the gas silica is selected from Evonik Degussa R972; preferably, the leveling agent is selected from silicone leveling agents; preferably, the leveling agent is selected from BYK300.

[0011] Furthermore, the acrylate adhesive layer of the present invention comprises the following raw material components by weight: 90-100 parts of acrylate resin, 1-5 parts of epoxy resin, and 1-10 parts of isocyanate curing agent. The thickness of the acrylate adhesive layer is 5-10 μm.

[0012] Furthermore, the number average molecular weight of the acrylic resin of the present invention is 100,000 to 1,000,000, the Tg value is -60 to -40°C, the solid content is 30% to 50%, the viscosity is 10,000±5,000cps (23±2°C), and the acid value is 20 to 50mgKOH / g; the acrylic resin is selected from Zongyan C-439; the epoxy resin is selected from the epoxy resin of meta-phenylenediamine; and the isocyanate curing agent is Bayer N3390.

[0013] Furthermore, the thickness of the non-silicone release film layer of the present invention is 25-75 μm, and the release force is 5-20 gf / 25 mm.

[0014] Furthermore, the thickness of the PET substrate layer of the present invention is 6-10 μm, and the small molecule precipitates are less than 0.2% (by weight) under the conditions of 180±1° C. and 60±1 min.

[0015] Another technical object of the present invention is to provide a method for preparing a PVD process protective film, comprising the following steps:

[0016] 1) dissolving the raw material of the acrylate adhesive layer with a solvent, such as toluene or ethyl acetate (the amount of the solvent used is 2 to 3 times the weight of the acrylate adhesive layer) to obtain a glue mixture;

[0017] 2) coating the glue mixture on the non-silicone release film layer, drying, laminating with the PET substrate film, and rolling;

[0018] 3) dissolving the coating layer raw materials with a solvent (e.g., toluene, ethyl acetate) (the amount of the solvent used is 2 to 3 times the weight of the coating layer) to obtain a coating mixture;

[0019] 4) Apply the coating mixture on the other side of the PET substrate film, dry, roll up, and mature.

[0020] Compared with the prior art, the present invention has the following beneficial effects: the PVD process protective film of the present invention adds a coating layer to the PET protective film, thereby playing a role in supporting the protective film, reducing deformation of the protective film, controlling expansion and shrinkage, and preventing adverse conditions such as overflow plating in the PVD process. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of the high temperature resistant PVD process protective film of the present invention.

[0022] 1- coating layer; 2- PET substrate layer; 3- acrylic resin adhesive layer; 4- non-silicone release film layer. DETAILED DESCRIPTION

[0023] In order to better illustrate the technical purpose, technical solution and advantages of the present invention, the present invention is further described in conjunction with the accompanying drawings and specific embodiments. The unit of weight parts mentioned in the embodiments is gram.

[0024] like Figure 1 As shown, the PVD process protective film of the present invention includes a coating layer, a PET substrate film, an acrylate adhesive layer and a non-silicon release film layer.

[0025] The thickness of the PET substrate layer is 7 μm, and the small molecule precipitates of the PET substrate film are less than 0.2% under high temperature conditions (180° C. for 160 min). The thickness of the non-silicone release film is 50 μm, and the release force is 10 gf / 25 mm.

[0026] 1. Preparation of Acrylate Adhesive Layer

[0027] The formula of the acrylic adhesive layer includes the following components by weight:

[0028]

[0029] The number average molecular weight of the acrylate resin is 700,000, the Tg value is -56°C, the solid content is 30%, the viscosity is 10,000-15,000 cps (2312°C), and the acid value is 30 mgKOH / g; the acrylate resin is Zongyan C-439; the epoxy resin is an epoxy resin of the m-phenylenediamine type; and the isocyanate curing agent is Bayer N3390.

[0030] The acrylic adhesive layer can be prepared on site by weighing and mixing according to the formula.

[0031] 2. Preparation of coating layer

[0032] Coating layer formulation

[0033] The raw materials for preparation include the following components by weight, as shown in Table 1:

[0034] Table 1 Formulation of coating layer of Examples 1-5

[0035] The acrylic resin used in the coating layer has a Tg value of 47°C (theoretical value), a solid content of 55%, a viscosity of 7000-10000mPa.s / 25°C, and a hydroxyl value of 49.5mgKOH / g.

[0036] The coating layer can be prepared on site by weighing and mixing according to the formula.

[0037] 3. Preparation method of protective film

[0038] The method for preparing the protective film comprises the following steps:

[0039] 1) Add the raw material components of the acrylate adhesive layer and ethyl acetate (twice the weight of the acrylate adhesive layer) into a reactor, stir at room temperature for 30 minutes at a stirring speed of 300-500 r / min to obtain an acrylate glue mixed solution.

[0040] 2) Apply the acrylic ester glue mixture on the release film layer, dry at 110°C, laminate with the PET substrate layer (low precipitation PET film), and roll up. The thickness of the acrylic ester glue layer is 6 μm.

[0041] 3) As shown in Table 1, add the hydroxy acrylate resin of the coating layer, ethyl acetate (the amount of the solvent is 2 times the total weight of the coating layer), and the leveling agent into the reactor, stir it on the machine, and stir it at a speed of 500-800r / min. Slowly add the gas silicon while stirring, and after all the powder is stirred into the hydroxy acrylate resin, disperse it at a high speed of 2500-3000 for 10-20 minutes. After all the powder is dispersed, add ethyl acetate (20% of the total weight of the solvent) and the coating layer curing agent, stir evenly, and obtain a coating mixture.

[0042] 4) The coating mixture is coated on the other side of the PET film in step 2), dried at 120°C, and rolled up. The coating layer thickness is 5 μm.

[0043] 5) The protective film is placed in a curing chamber for curing at a temperature of 55° C. for 72 hours to obtain the coated PVD process protective film.

[0044] Comparative Example 1

[0045] 1. The PVD process protective film described in Comparative Example 1 comprises a low-precipitation PET film, an acrylate adhesive layer, and a non-silicon release film.

[0046] 2. The thickness of the PET substrate layer is 7 μm7 and the small molecule precipitates of the PET substrate layer are less than 0.2% under high temperature conditions (180°C 160 min). The thickness of the non-silicon PET release film is 50 μm and the release force is 10 gf / 25 mm.

[0047] 3. The raw materials for preparing the acrylic adhesive layer include the following components in parts by weight:

[0048]

[0049] The number average molecular weight of the acrylic resin is 7000007Tg value is -56℃, solid content is 30%, viscosity is 1000015000cps (2312℃)7acid value is 30mgKOH / g7Epoxy resin is an epoxy resin of the m-phenylenediamine type. Isocyanate curing agent is Bayer N3390.

[0050] 4. Comparative Example 1 The method for preparing the protective film comprises the following steps:

[0051] 1) Add the raw materials for preparing the acrylate adhesive layer and the solvent (toluene, ethyl acetate) into a reaction kettle, stir at room temperature for 30 minutes at a stirring speed of 300-500 r / min to obtain an acrylate glue mixed solution (the acrylate adhesive layer can be dissolved by the method of the embodiment of the present invention).

[0052] 2) The acrylic ester glue mixture is coated on the release film layer, dried at 110°C, and then compounded with the substrate layer (low precipitation PET film) and rolled up. The thickness of the acrylic ester glue layer is 6 μm.

[0053] 3) The protective film of step 2) is placed in a curing chamber for curing at a temperature of 50-55° C. for 72 hours to obtain the high temperature resistant PVD process protective film.

[0054] Comparative Example 2

[0055] 1. In this embodiment, a high temperature resistant PVD process protective film is provided, including a low precipitation PET film, an acrylate adhesive layer, and a non-silicon release film.

[0056] 2. The thickness of the low precipitation PET film is 7 μm7 and the small molecule precipitates of the low precipitation PET film are less than 0.2% under high temperature conditions (180°C 160 min). The thickness of the non-silicon PET release film is 50 μm and the release force is 10 gf / 25 mm.

[0057] 3. The raw materials for preparing the acrylic adhesive layer include the following components in parts by weight:

[0058]

[0059] The average molecular weight of hydroxy acrylate resin is 1000007Tg value is -50℃, solid content is 40%, viscosity is 500012000cps (2312℃), hydroxyl value is 33mgKOH / g7, and the isocyanate curing agent is Bayer N3390.

[0060] 4. The preparation method comprises the following steps:

[0061] 1) Add the raw materials for preparing the acrylic adhesive layer and the diluent (toluene, ethyl acetate) into a reaction kettle, stir at room temperature for 30 minutes at a stirring speed of 300-500 r / min to obtain an acrylic adhesive mixed solution.

[0062] 2) The acrylic ester glue mixture is coated on the release film layer, dried at 110°C, and then compounded with the substrate layer (low precipitation PET film) and rolled up. The thickness of the acrylic ester glue layer is 6 μm.

[0063] 3) The protective film of step 2) is placed in a curing chamber for curing at a temperature of 55° C. for 72 hours to obtain the high temperature resistant PVD process protective film.

[0064] 2. Performance Test

[0065] Test method: Punch the protective film sample with a hole puncher and stick it to the object (glass). Use a two-dimensional image measuring instrument to calibrate the basic data of the circle. After the PVD process, use the two-dimensional image measuring instrument to calibrate the deformation data of the circle. Calculate the expansion and contraction rate. Expansion and contraction rate = (radius after PVD process - original radius) / original radius 1100%.

[0066] Examples 1-5 are all high temperature resistant PVD process protective films with a coating layer. Comparative Examples 1 and 2 are ordinary high temperature resistant PVD process protective films (without a coating layer), and their expansion and contraction rates are tested:

[0067] Table 2 Expansion and shrinkage results of Examples 1-5 and Comparative Examples 1-2

[0068] Test items Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Expansion and Shrinkage Rate 0.20％ 0.18％ 0.15％ 0.22％ 0.25％ 0.45％ 0.50％

[0069] Experimental conclusion: The coating layer added to the PVD process protective film of Examples 1 to 5 can effectively support the protective film, reduce the deformation of the protective film, and control the expansion and shrinkage rate in the PVD process, thereby reducing the undesirable conditions such as over-plating and under-plating in the PVD process. The formula of the coating layer includes hydroxy acrylate resin, isocyanate curing agent, gas silicon and leveling agent, which can control the expansion and shrinkage rate range of 0.15%-0.25%, thereby playing a role in supporting the protective film and reducing the deformation of the protective film. However, since there is no coating layer added to Comparative Examples 1 and 2, their expansion and shrinkage rates are above 0.45%, which obviously does not meet the expansion and shrinkage rate requirements.

[0070] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. In addition, the present invention may also be implemented in other ways. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the technical solution of the present invention may be modified or equivalently replaced, but these modifications or replacements are all within the protection scope of the present invention.

Claims

1. A PVD process protective film, characterized in that: It comprises a coating layer, a PET substrate layer, an acrylate adhesive layer and a non-silicone release film layer; the coating layer comprises the following raw material components by weight: 80-100 parts of hydroxy acrylic resin, 5-20 parts of coating layer curing agent, 1-15 parts of gas silicone, and 0.1-1.0 parts of leveling agent; the hydroxy acrylic resin has a Tg value of 40-60°C, a solid content of 50-60%, a viscosity of 7000-10000mpa.s / 25°C, and a hydroxyl value of 10-100mgKOH / g; the coating layer curing agent is selected from HDI or TDI type closed curing agent.

2. The PVD process protective film according to claim 1, characterized in that: The coating layer curing agent is selected from Bayer BL3175.

3. The PVD process protective film according to claim 1, characterized in that: The fumed silica is selected from hydrophobic fumed silica.

4. The PVD process protective film according to claim 3, characterized in that: The gas silicon is selected from Evonik Degussa R972.

5. The PVD process protective film according to claim 1, characterized in that: The leveling agent is selected from silicone leveling agents.

6. The PVD process protective film according to claim 5, characterized in that: The leveling agent is selected from BYK300.

7. The PVD process protective film according to claim 1, characterized in that: The acrylate adhesive layer comprises the following raw material components by weight: 90-100 parts of acrylate resin, 1-5 parts of epoxy resin, and 1-10 parts of isocyanate curing agent.

8. The PVD process protective film according to claim 7, characterized in that: The number average molecular weight of the acrylic resin is 100,000 to 1,000,000, the Tg value is -60 to -40°C, the solid content is 30% to 50%, the viscosity is 10,000±5,000 cps at a temperature of 23±2°C, and the acid value is 20 to 50 mgKOH / g; the epoxy resin is selected from the epoxy resin of the meta-phenylenediamine type; and the isocyanate curing agent is Bayer N3390.

9. The PVD process protective film according to claim 1, characterized in that: The non-silicone release film layer has a thickness of 25-75 μm and a release force of 5-20 gf / 25 mm.

10. The PVD process protective film according to claim 1, characterized in that: The thickness of the PET substrate layer is 6-10 μm, and the small molecule precipitate is less than 0.2% under the conditions of 180±1° C. and 60±1 min.

11. A method for preparing a PVD process protective film, characterized in that: The following steps are involved: 1) Dissolving the raw materials of the acrylic adhesive layer to obtain a glue mixture; 2) Apply the glue mixture on the non-silicone release film layer, dry it, laminate it with the PET substrate film, and roll it up; 3) dissolving the raw materials of the coating layer to obtain a coating mixture; 4) Apply the coating mixture on the other side of the PET substrate film, dry, reel and mature.

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