Silica gel protective film and preparation method thereof

Abstract

The invention discloses a silica gel protective film and a preparation method thereof, and belongs to the technical field of protective film preparation. The silica gel protective film comprises a base material layer, a silica gel bonding layer and a protective layer from bottom to top, the silica gel bonding layer is prepared from the following components in parts by weight: 80 to 100 parts of organic silicon pressure-sensitive adhesive, 0.3 to 0.6 part of cross-linking agent, 0.05 to 0.1 part of anchoring agent, 0.25 to 0.5 part of catalyst, 0.1 to 0.2 part of inhibitor and 50 to 70 parts of solvent. The preparation method comprises the following steps: sequentially adding the organic silicon pressure-sensitive adhesive, the cross-linking agent, the anchoring agent, the inhibitor, the catalyst and the solvent into a reaction container, uniformly stirring, and coating. The dosage of the anchoring agent is reduced to 0.05-0.1% from 0.3% of the weight of an organic silicon pressure-sensitive adhesive in the prior art, and the silicon transfer rate of the prepared silica gel protective film can be controlled within 10% and is far lower than the industrial standard.

Description

Technical Field

[0001] The invention belongs to the technical field of protective film preparation, and specifically relates to a silicone protective film and a preparation method thereof. Background Art

[0002] Silicone protective film is a screen protective film mainly used to protect electronic products. The mainstream silicone protective film is PET silicone screen protective film, which is suitable for various screen protections, computer keyboards and other protections during the production process. Although silicone pressure-sensitive adhesive protective film can be applied to release layers with different peeling forces and has a good effect, it is easy to leave residues at the interface of the release layer during the subsequent transfer process, and the residual silicon-containing material is easy to cause silicon pollution, and affect the viscosity and service life of the adhesive layer.

[0003] The patent application with publication number CN 116925667 A discloses a method comprising the following steps: adding a diluent solvent, vinyl polysiloxane, hydrogen-containing polysiloxane and 3-chloropropyltriethoxysilane, a reaction product of sodium silicate, chlorotrimethylsilane and isopropyl alcohol, hydrogen-containing polysiloxane and tetramethyldivinyldisiloxane into a reaction kettle and stirring to obtain a dispersion; adding a silane coupling agent, a Pt catalyst and 2-methyl-3-butyn-2-ol while stirring the dispersion, and mixing them uniformly to obtain an organic silicone pressure-sensitive adhesive; coating the organic silicone pressure-sensitive adhesive on a substrate, coating the pressure-sensitive adhesive on the surface of the substrate by a tape coater, and curing in an oven after coating to obtain an adhesive layer. The silicone pressure-sensitive adhesive prepared in this application improves the efficiency of rapid winding of protective film production, but inevitably, the silicone protective film adhesive layer will produce silicon transfer, causing a series of problems such as cohesive failure, substrate damage, transmission residue, and even easily causing silicon contamination; based on this design, preparing a silicone protective film that reduces silicon transfer is an urgent problem to be solved. Summary of the invention

[0004] The object of the present invention is to provide a silicone protective film and a preparation method thereof, so as to reduce the silicon transfer rate of the silicone protective film.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A silicone protective film comprises, from bottom to top, a substrate layer, a silicone adhesive layer and a protective layer;

[0007] The silicone adhesive layer comprises, by weight, 80-100 parts of organic silicone pressure-sensitive adhesive, 0.3-0.6 parts of cross-linking agent, 0.05-0.1 parts of anchoring agent, 0.25-0.5 parts of catalyst, 0.1-0.2 parts of inhibitor and 50-70 parts of solvent.

[0008] Furthermore, the substrate film material is one or a combination of BOPP, BOPET, BOPA, PET, PE, PC, TAC, PP, PS, PMMA, TPU, PI, PVB and PVC.

[0009] Furthermore, the protective layer is a release film protective layer.

[0010] Furthermore, the model of the organic silicone pressure-sensitive adhesive is 7687N, 7666, 76000; and the solid content is 20%-80%.

[0011] Among them, silicone pressure-sensitive adhesive generally refers to pressure-sensitive adhesive with silicone polymer as the main body, or acrylic and silicone-modified rubber pressure-sensitive adhesive modified by silicone polymer. The solid content of silicone pressure-sensitive adhesive is generally between 10% and 100%, and the viscosity ranges from a few hundred CPS to millions of CPS.

[0012] Furthermore, the cross-linking agent model is H-165.

[0013] The role of the crosslinking agent is to generate chemical bonds between linear molecules, so that the linear molecules are connected to each other to form a network structure, thus improving the strength and elasticity of the rubber. For example, polyethylene, polyvinyl chloride, chlorinated polyethylene, EVA, polystyrene, acrylic acid, polyacrylate, polyalkyl acrylate, epoxy resin, DAP (polydiallyl phthalate), unsaturated polyester, thermoplastic polyester, TAIC, etc. can all use crosslinking agents to improve strength, heat resistance, wear resistance, solvent resistance and other properties.

[0014] Furthermore, the model of the anchoring agent is 297.

[0015] The main function of the anchoring agent is to improve the surface treatment ability, improve the dispersion and adhesion of the resin in the organic pressure-sensitive adhesive, and improve the bonding strength and applicability to climate, water vapor and other environments.

[0016] Furthermore, the model of the catalyst is one of F50040, 4000, 4500 or a combination of several of them.

[0017] The role of the catalyst is to change the chemical reaction rate of the reactants (increase or decrease) without changing the chemical equilibrium, and its own quality and chemical properties will not change before and after the chemical reaction.

[0018] Furthermore, the inhibitor is of the type I-224, PH212 or a combination of several of them.

[0019] Among them, inhibitors, also known as retarders, have the same effect as negative catalysts, but are the opposite of catalysts. They are substances used to block or reduce the speed of chemical reactions. They cannot stop polymerization reactions, but only slow them down.

[0020] Furthermore, the solvent is one or a combination of toluene, xylene, ethyl acetate, butanone, 100-200 solvent oil, and evaporates after preparation.

[0021] A method for preparing a silicone protective film comprises the following steps:

[0022] The silicone pressure-sensitive adhesive, cross-linking agent, anchoring agent, catalyst, inhibitor and solvent are sequentially added into a reaction container, stirred evenly and then coated on the substrate film, heated and cured to form a silicone adhesive layer, and then a protective layer is attached to the surface of the silicone adhesive layer to obtain a silicone protective film.

[0023] Furthermore, the temperature of the heating and curing is 100-200°C.

[0024] Furthermore, the thickness of the substrate layer is 10 to 200 μm, the thickness of the silicone adhesive layer is 10 to 1000 μm, and the thickness of the protective layer is 10 to 200 μm.

[0025] Beneficial effects of the present invention:

[0026] (1) The present invention provides a silicone protective film, which reduces the area of ​​silicon transfer and thus reduces the amount of silicon transfer by reducing the amount of anchoring agent in the silicone layer. Compared with the prior art, the present invention reduces the amount of anchoring agent from 0.3% by weight of the silicone pressure-sensitive adhesive in the prior art to 0.05% to 0.1%. The silicon transfer rate of the obtained silicone protective film can be controlled within 10%, which is far lower than the industry standard.

[0027] (2) The present invention provides a method for preparing a silicone protective film. The silicone protective film prepared by the method reduces the amount of silicon transfer and increases the service life of the silicone protective film without affecting the viscosity and performance of the silicone protective film itself. At the same time, the preparation method is simple and easy, the raw material price is low, and it is suitable for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below in conjunction with the accompanying drawings.

[0029] Figure 1 The figure is a schematic diagram of the structure of the silicone protective film prepared by the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1

[0032] 100 parts of silicone pressure-sensitive adhesive 7687N, 0.42 parts of cross-linking agent H-165, 0.1 parts of anchoring agent 297, 0.35 parts of catalyst F50040, 0.1 parts of inhibitor I-224 and 60 parts of toluene are added to a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, and cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer, the thickness of the substrate layer is 100 μm, the thickness of the silicone adhesive layer is 250 μm, and the thickness of the release film protective layer is 100 μm, to obtain a silicone protective film.

[0033] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0034] Example 2

[0035] Compared with Example 1, this embodiment differs in that the thicknesses of the substrate layer, the silicone adhesive layer and the release film protective layer are changed. The specific implementation steps are as follows:

[0036] 100 parts of silicone pressure-sensitive adhesive 7687N, 0.42 parts of cross-linking agent H-165, 0.1 parts of anchoring agent 297, 0.35 parts of catalyst F50040, 0.1 parts of inhibitor I-224 and 60 parts of toluene are added to a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, and cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer, the thickness of the substrate layer is 100 μm, the thickness of the silicone adhesive layer is 500 μm, and the thickness of the release film protective layer is 100 μm, to obtain a silicone protective film.

[0037] The remaining raw materials and preparation process remain the same as in Example 1.

[0038] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0039] Example 3

[0040] Compared with Example 1, this embodiment differs in that the thicknesses of the substrate layer, the silicone adhesive layer and the release film protective layer are changed. The specific implementation steps are as follows:

[0041] 100 parts of silicone pressure-sensitive adhesive 7687N, 0.42 parts of cross-linking agent H-165, 0.1 parts of anchoring agent 297, 0.35 parts of catalyst F50040, 0.1 parts of inhibitor I-224 and 60 parts of toluene are added into a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer, the thickness of the substrate layer is 150 μm, the thickness of the silicone adhesive layer is 150 μm, and the thickness of the release film protective layer is 150 μm, to obtain a silicone protective film.

[0042] The remaining raw materials and preparation process remain the same as in Example 1.

[0043] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0044] Example 4

[0045] Compared with Example 1, this embodiment differs in that the ratio of raw materials is changed, and the specific implementation steps are as follows:

[0046] 80 parts of silicone pressure-sensitive adhesive 7687N, 0.3 parts of cross-linking agent H-165, 0.05 parts of anchoring agent 297, 0.25 parts of catalyst F50040, 0.1 parts of inhibitor I-224 and 50 parts of toluene are added into a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer, the thickness of the substrate layer is 100 μm, the thickness of the silicone adhesive layer is 250 μm, and the thickness of the release film protective layer is 100 μm, to obtain a silicone protective film.

[0047] The remaining raw materials and preparation process remain the same as in Example 1.

[0048] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0049] Example 5

[0050] Compared with Example 1, this embodiment differs in that the ratio of raw materials is changed, and the specific implementation steps are as follows:

[0051] 120 parts of silicone pressure-sensitive adhesive 7687N, 0.6 parts of cross-linking agent H-165, 0.1 parts of anchoring agent 297, 0.5 parts of catalyst F50040, 0.2 parts of inhibitor I-224 and 70 parts of toluene are added to a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, and cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer. The thickness of the substrate layer is 100 μm, the thickness of the silicone adhesive layer is 250 μm, and the thickness of the release film protective layer is 100 μm, so as to obtain a silicone protective film.

[0052] The remaining raw materials and preparation process remain the same as in Example 1.

[0053] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0054] Example 6

[0055] Compared with Example 1, the difference between this embodiment and Example 1 is that the silicone pressure-sensitive adhesive 7687N is replaced by the silicone pressure-sensitive adhesive 7666. The specific implementation steps are as follows:

[0056] 100 parts of silicone pressure-sensitive adhesive 7666, 0.42 parts of cross-linking agent H-165, 0.1 parts of anchoring agent 297, 0.35 parts of catalyst F50040, 0.1 parts of inhibitor I-224 and 60 parts of toluene are added to a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, and cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer. The thickness of the substrate layer is 100 μm, the thickness of the silicone adhesive layer is 250 μm, and the thickness of the release film protective layer is 100 μm, so as to obtain a silicone protective film.

[0057] The remaining raw materials and preparation process remain the same as in Example 1.

[0058] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0059] Example 7

[0060] Compared with Example 1, this example differs in that the types of catalyst and inhibitor are changed. The specific implementation steps are as follows:

[0061] 100 parts of silicone pressure-sensitive adhesive 7687N, 0.42 parts of cross-linking agent H-165, 0.1 parts of anchoring agent 297, 0.35 parts of catalyst 4000, 0.1 parts of inhibitor PH21 and 60 parts of toluene were added into a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, cured at 150°C to form a silicone adhesive layer, and then a release film protective layer was attached to the surface of the silicone adhesive layer, the thickness of the substrate layer was 100 μm, the thickness of the silicone adhesive layer was 250 μm, and the thickness of the release film protective layer was 100 μm, to obtain a silicone protective film.

[0062] The remaining raw materials and preparation process remain the same as in Example 1.

[0063] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0064] Comparative Example 1

[0065] Compared with Example 1, this comparative example is different in that the amount of anchoring agent is increased, and the specific implementation steps are as follows:

[0066] 100 parts of silicone pressure-sensitive adhesive 7687N, 0.42 parts of cross-linking agent H-165, 0.3 parts of anchoring agent 297, 0.35 parts of catalyst F50040, 0.1 parts of inhibitor I-224 and 60 parts of toluene are added to a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, and cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer, the thickness of the substrate layer is 100 μm, the thickness of the silicone adhesive layer is 250 μm, and the thickness of the release film protective layer is 100 μm, to obtain a silicone protective film.

[0067] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0068] Comparative Example 2

[0069] Compared with Example 1, this comparative example is different in that no anchoring agent is added, and the specific implementation steps are as follows:

[0070] 100 parts of silicone pressure-sensitive adhesive 7687N, 0.42 parts of cross-linking agent H-165, 0.1 parts of anchoring agent 297, 0.35 parts of catalyst F50040, 0.1 parts of inhibitor I-224 and 60 parts of toluene are added to a reaction container in sequence, stirred evenly and coated on the substrate film BOPP, and cured at 150°C to form a silicone adhesive layer, and then a release film protective layer is attached to the surface of the silicone adhesive layer, the thickness of the substrate layer is 100 μm, the thickness of the silicone adhesive layer is 250 μm, and the thickness of the release film protective layer is 100 μm, to obtain a silicone protective film.

[0071] The remaining raw materials and preparation process remain the same as in Example 1.

[0072] The structure of the silicone protective film prepared in the above steps is as follows: Figure 1 shown.

[0073] The performance of the silicone protective films prepared in Examples 1 to 7 and Comparative Examples 1 to 2 was tested.

[0074] Adhesion of protective film (g / in): stick the test sample to the adhesive steel plate and let it stand for 20 minutes; tear off 10mm of the sample strip from the bottom to the top on the steel plate, then insert the bottom of the steel plate completely into the bottom of the card slot of the tensile testing machine, and then move the steel plate to align the sample strip with the adhesive strip, and tighten the screws to fix the steel plate; stick the torn 10mm strip completely overlapping the adhesive strip together, and select a 180° peel force test speed of 300mm / min to test its adhesion.

[0075] Light transmittance (%): According to GB T 2410-2008 “Determination of light transmittance and haze of transparent plastics”, the light transmittance of the silicone protective film obtained in each embodiment and comparative example of the present application was tested;

[0076] Silicon transfer rate (%): The protective film is attached to the special 188μm PET and loaded with a load (7.5g / cm 2 ) After placement, tear off the protective film. At this time, the area covered by the protective film is the silicon-contaminated area; use the special tape NITTO31B to test the adhesion of the uncontaminated (NITTO31B tape adhesion) and contaminated areas, and do two or more groups to find the average.

[0077] Calculate the silicon transfer rate: 1-(viscosity after contamination / viscosity of NITTO 31B tape)*100%

[0078] The results are shown in Table 1:

[0079] Table 1

[0080]

[0081]

[0082] According to the embodiments, comparative examples and combined with Table 1, it can be seen that the difference between Examples 2-3 and Example 1 lies in the change of the thickness ratio of the substrate layer, the silicone adhesive layer and the release film protective layer; the difference between Examples 4-5 and Example 1 lies in the change of the raw material ratio of the silicone adhesive layer; the difference between Examples 6-7 and Example 1 lies in the replacement of the raw materials of the silicone adhesive layer within a reasonable range. From the results, the prepared silicone protective films all have good protective film viscosity, light transmittance and low silicon transfer rate, and excellent performance in all aspects.

[0083] Compared with Example 1, the difference between Comparative Example 1 is that the amount of anchoring agent is increased, which improves the silicon transfer rate. Compared with Example 1, the difference between Comparative Example 2 and Example 1 is that no anchoring agent is added, and the viscosity and transmittance of the protective film show a decreasing trend. Combining Comparative Examples 1-2 with the examples, it can be seen that the anchoring agent can improve the surface treatment ability, improve the dispersibility and adhesion of the resin in the organic pressure-sensitive adhesive, and improve the bonding strength, while too much anchoring agent will increase the silicon transfer rate of the silicone protective film and reduce the viscosity and service life of the adhesive layer.

[0084] In summary, the present invention provides a silicone protective film and a preparation method thereof. The prepared silicone protective film has good performance. The amount of anchoring agent used is reduced from 0.3% by weight of the silicone pressure-sensitive adhesive in the prior art to 0.05% to 0.1%. The silicon transfer rate of the prepared silicone protective film can be controlled within 10%, which is far lower than the industry standard. It is suitable for large-scale industrial production and has good application prospects.

[0085] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0086] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A silicone protective film, characterized in that: From bottom to top, it includes a substrate layer, a silicone adhesive layer and a protective layer; The silicone adhesive layer comprises, by weight, 80-100 parts of organic silicone pressure-sensitive adhesive, 0.3-0.6 parts of cross-linking agent, 0.05-0.1 parts of anchoring agent, 0.25-0.5 parts of catalyst, 0.1-0.2 parts of inhibitor and 50-70 parts of solvent.

2. A silicone protective film according to claim 1, characterized in that: The substrate film material is one or a combination of BOPP, BOPET, BOPA, PET, PE, PC, TAC, PP, PS, PMMA, TPU, PI, PVB and PVC.

3. The silicone protective film according to claim 1, characterized in that: The protective layer is a release film protective layer.

4. The silicone protective film according to claim 1, characterized in that: The model of the organic silicon pressure-sensitive adhesive is 7687N, 7666, 76000; the solid content is 20%-80%.

5. The silicone protective film according to claim 1, characterized in that: The cross-linking agent model is H-165; the anchoring agent model is 297.

6. The silicone protective film according to claim 1, characterized in that: The model of the catalyst is one of F50040, 4000, 4500 or a combination of several thereof; the model of the inhibitor is one of I-224 and PH212 or a combination of several thereof.

7. The silicone protective film according to claim 1, characterized in that: The solvent is one or a combination of toluene, xylene, ethyl acetate, butanone, 100-200 solvent oil, and is volatilized after preparation.

8. A method for preparing a silicone protective film according to any one of claims 1 to 7, characterized in that: The steps include: The silicone pressure-sensitive adhesive, cross-linking agent, anchoring agent, catalyst, inhibitor and solvent are sequentially added into a reaction container, stirred evenly and then coated on the substrate film, heated and cured to form a silicone adhesive layer, and then a protective layer is attached to the surface of the silicone adhesive layer to obtain a silicone protective film.

9. The method for preparing a silicone protective film according to claim 8, characterized in that: The temperature of the heating curing is 100-200°C.

10. The method for preparing a silicone protective film according to claim 8, characterized in that: The thickness of the substrate layer is 10 to 200 μm, the thickness of the silicone adhesive layer is 10 to 1000 μm, and the thickness of the protective layer is 10 to 200 μm.

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