Fluorine-free silicon high-temperature resistant protective film and preparation method thereof

Abstract

The application discloses a fluorine-free silicon high-temperature-resistant protective film and a preparation method thereof. The method comprises the following steps: weighing ethyl acetate, toluene, isooctyl acrylate, n-butyl acrylate, methyl methacrylate, acrylic acid, a special monomer and an initiator, stirring the above substances to obtain solution A; weighing solution A and heating solution A to 78-85 DEG C for stirring reaction for a period of time; after the reaction is completed, 200-300 parts of solution A is continuously added to the system for dropwise addition for 0.5-2 hours; after the dropwise addition is completed, the initiator is added and the reaction is continuously carried out; after the reaction is completed, 2-8 parts of a crosslinking monomer is added after the temperature is reduced to room temperature; and the adhesive for the fluorine-free silicon high-temperature-resistant protective film is obtained after stirring for 10-20 minutes. The adhesive is coated on PET and vacuum dried. The application keeps the high initial adhesion and low peeling force of the traditional protective film system, and greatly improves the bonding performance of the protective film at high temperature through the cooperation of the special monomer, the crosslinking monomer and the protective film adhesive.

Description

Technical Field

[0001] This invention relates to a fluorine-free silicon high-temperature resistant protective film and its preparation method. Background Technology

[0002] The essential function of protective films is to protect delicate or expensive items. However, with the rapid development of modern technology, the definition of protective films has gradually broadened, no longer limited to macroscopic fields, but rather applied in specific areas. Protective film materials can be categorized according to their application: metal product surfaces, plastic product surfaces, automotive paint protection, electronic screen surfaces, special profile product surfaces, and other product surfaces. These application scenarios continuously increase the performance requirements for protective films, such as high-temperature resistance, UV resistance, and resistance to humid heat conditions.

[0003] Analyzing the chemical structure of the protective film reveals a contradiction between its inherent chemical properties and the high-temperature resistance, UV resistance, and other weather-resistant characteristics it possesses. This is because, during use, the protective film not only exhibits high initial tack but, more importantly, requires minimal force to peel off from the surface of the protected object. This necessitates a chemical structure with a low glass transition temperature and low cohesive strength. High-temperature resistance and other properties are directly positively correlated with cohesive strength; therefore, developing a specialized protective film system with these properties is a pressing scientific challenge. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of high-temperature adhesive residue and increased high-temperature peel strength in conventional protective film adhesive systems, and to provide a fluorine-free silicone high-temperature resistant protective film and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a fluorine-free silicon high-temperature resistant protective film, wherein the method is as follows:

[0007] Step 1: Weigh out 150-300 parts ethyl acetate, 50-100 parts toluene, 100-200 parts isooctyl acrylate, 70-150 parts n-butyl acrylate, 30-60 parts methyl methacrylate, 1-3 parts acrylic acid, 2-7 parts special monomers, and 0.5-3 parts initiator according to the following weight proportions.

[0008] Step 2: Add all the substances from Step 1 into a flask and stir at a speed of 30-80 rpm for 10-20 minutes to obtain solution A;

[0009] Step 3: Weigh 100-300 parts of solution A according to the mass fraction and heat it to 78℃-85℃. Stir at 100-150 rpm for 1-2 hours.

[0010] Step 4: After the reaction is complete, continue to add 200-300 parts of solution A to the system dropwise over a period of 0.5-2 hours.

[0011] Step 5: After the dropwise addition is complete, add 0.3-0.8 parts of initiator and continue the reaction for 2-4 hours. After the reaction is complete and the system temperature drops to room temperature, add 2-8 parts of crosslinking monomer to the system. Stir for 10-20 minutes to obtain the fluorine-free silicone high-temperature resistant protective film adhesive. The chemical structural formula of the crosslinking monomer is as follows: Figure 1 As shown;

[0012] Step 6: Weigh 10-30 parts of the prepared adhesive according to the mass ratio and coat it onto the PET. After coating, place it in a vacuum oven at 140-170℃ and dry for 5-10 minutes to obtain a fluorine-free silicone high-temperature resistant protective film.

[0013] Furthermore, in step one, the special monomer is an acrylonitrile monomer containing a double-bonded reactive group.

[0014] Furthermore, in step one, the acrylonitrile monomer containing a double-bonded reactive group is one of acrylonitrile, 3-cyclopentylacrylonitrile, or 3-phenylacrylonitrile.

[0015] Furthermore, in step five, the initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile, and dicumyl peroxide.

[0016] Furthermore, in step five, the crosslinking monomer is a polyether-modified cyanate resin, a bisphenol A type cyanate resin, or a triazine type cyanate resin.

[0017] A fluorine-free silicon high-temperature resistant protective film obtained by the above preparation method.

[0018] The advantages of this invention over the prior art are as follows: This invention designs an acrylate polymer with high-temperature micro-crosslinking function and prepares it by solution polymerization. Based on this, combined with the use of special crosslinking monomers, a fluorine-free silicone high-temperature resistant protective film adhesive is prepared and applied in the field of protective films.

[0019] This invention maintains the high initial tack and low peel strength of traditional protective film systems. Through the combined use of special monomers, crosslinking monomers, and protective film adhesives, it significantly improves the adhesion performance of the protective film at high temperatures. By controlling parameters such as monomer dosage, monomer type, crosslinking agent dosage, and structure, the degree of crosslinking and the crosslinking network can be adjusted, ultimately resulting in protective films with different high-temperature resistant adhesive strengths. The interaction, primarily the chemical reaction between the crosslinking monomers and the special monomers, forms a crosslinking network with a unique structure that greatly improves the adhesion performance of the protective film under high-temperature conditions. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the chemical structure of the crosslinking monomer;

[0021] Figure 2 Digital photographs of a fluorine-free silicone high-temperature resistant protective film adhesive that can withstand temperatures up to 160°C;

[0022] Figure 3 Digital photographs of a fluorine-free silicone high-temperature resistant protective film adhesive that can withstand temperatures up to 200°C;

[0023] Figure 4 Peel force data for a 160℃ fluorine-free silicone high-temperature protective film adhesive;

[0024] Figure 5 Peel force data for a 180℃ fluorine-free silicone high-temperature resistant protective film adhesive;

[0025] Figure 6 NMR data for a 160℃ fluorine-free silicone high-temperature protective film adhesive. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention that do not depart from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0027] Example 1: Preparation method of fluorine-free silicone high-temperature resistant protective film withstanding 160℃

[0028] First, weigh out 236 parts by weight of ethyl acetate, 55 parts by weight of toluene, 170 parts by weight of isooctyl acrylate, 85 parts by weight of n-butyl acrylate, 32 parts by weight of methyl methacrylate, 1.4 parts by weight of acrylic acid, 2.9 parts by weight of acrylonitrile, and 2.4 parts by weight of azobisisobutyronitrile. Add all the above substances to a flask and stir at a stirring speed of 45 rpm for 10 min to obtain solution A.

[0029] Next, according to the mass fraction, 237 parts of solution A were weighed and heated to 82°C. The stirring speed was 120 rpm and the reaction time was 1 h. After the reaction was completed, 230 parts of solution A were added dropwise to the system for 1.5 h. After the addition was completed, 0.7 parts of azobisisobutyronitrile were added and the reaction was continued for 2.2 h. After the reaction was completed and the system temperature was cooled to room temperature, 3.1 parts of polyether modified cyanate resin were added to the system. After stirring for 20 min, the fluorine-free silicone high-temperature resistant protective film adhesive was obtained.

[0030] Finally, weigh 12 parts of the prepared adhesive, coat it onto PET, and dry it in a vacuum oven at 150°C for 5 minutes to obtain a fluorine-free silicone high-temperature resistant protective film that can withstand 160°C.

[0031] Example 2: Preparation method of 180℃ fluorine-free silicone high-temperature resistant protective film

[0032] First, weigh out 175 parts by weight of ethyl acetate, 80 parts by weight of toluene, 131 parts by weight of isooctyl acrylate, 82 parts by weight of n-butyl acrylate, 47 parts by weight of methyl methacrylate, 2.1 parts by weight of acrylic acid, 4 parts by weight of 3-cyclopentylacrylonitrile, and 1.9 parts by weight of azobisisoheptanenitrile. Add all the above substances to a flask and stir at a stirring speed of 58 rpm for 13 min to obtain solution A.

[0033] Next, according to the mass fraction, 241 parts of solution A were weighed and heated to 79°C. The stirring speed was 110 rpm and the reaction time was 2 hours. After the reaction was completed, 267 parts of solution A were added dropwise to the system for 1.5 hours. After the addition was completed, 0.66 parts of azobisisobutyronitrile were added and the reaction was continued for 2.5 hours. After the reaction was completed and the system temperature was cooled to room temperature, 6 parts of bisphenol A cyanate resin were added to the system. After stirring for 15 minutes, the fluorine-free silicone high-temperature resistant protective film adhesive was obtained.

[0034] Finally, weigh 18 parts of the prepared adhesive, coat it onto PET, and dry it in a vacuum oven at 160°C for 8 minutes to obtain a fluorine-free silicone high-temperature resistant protective film that can withstand 180°C.

[0035] Example 3: Preparation method of fluorine-free silicone high-temperature resistant protective film resistant to 200℃

[0036] First, weigh out 160 parts by weight of ethyl acetate, 97 parts by weight of toluene, 120 parts by weight of isooctyl acrylate, 75 parts by weight of n-butyl acrylate, 57 parts by weight of methyl methacrylate, 2.7 parts by weight of acrylic acid, 5 parts by weight of 3-phenylacrylonitrile, and 0.55 parts by weight of dicumyl peroxide. Add all the above substances to a flask and stir at a stirring speed of 60 rpm for 18 min to obtain solution A.

[0037] Next, according to the mass fraction, weigh 285 parts of solution A and heat it to 78°C. Stir at 150 rpm for 1.5 h. After the reaction is complete, continue to add 286 parts of solution A to the system for 2 h. After the addition is complete, add 0.35 parts of dicumyl peroxide and continue the reaction for 3.5 h. After the reaction is complete and the system temperature drops to room temperature, add 6.5 parts of triazine cyanate resin to the system and stir for 18 min to obtain the fluorine-free silicone high-temperature resistant protective film adhesive.

[0038] Finally, weigh 25 parts of the prepared adhesive, coat it onto PET, and dry it in a vacuum oven at 170°C for 10 minutes to obtain a fluorine-free silicone high-temperature resistant protective film that can withstand 200°C.

[0039] Figure 2 and Figure 3 This demonstrates the excellent light transmittance of this adhesive system.

[0040] The prepared adhesive tape was pressed against a sample using a standard pressure roller (mass 2000±50g, rubber hardness Shore A 60±5) to ensure uniform contact. A 180° test was then performed to obtain the final peel force curve. Figure 4 and Figure 5 As shown, this protective film has good peelability.

[0041] Figure 6 This demonstrates the successful synthesis of the adhesive for this type of protective film.

Claims

1. A method for preparing a fluorine-free silicon high-temperature resistant protective film, characterized in that: The method is as follows: Step 1: Weigh out 150-300 parts ethyl acetate, 50-100 parts toluene, 100-200 parts isooctyl acrylate, 70-150 parts n-butyl acrylate, 30-60 parts methyl methacrylate, 1-3 parts acrylic acid, 2-7 parts special monomers, and 0.5-3 parts initiator according to the following weight proportions. Step 2: Add all the substances from Step 1 into a flask and stir at a speed of 30-80 rpm for 10-20 minutes to obtain solution A; Step 3: Weigh 100-300 parts of solution A according to the mass fraction and heat it to 78℃-85℃. Stir at 100-150 rpm for 1-2 hours. Step 4: After the reaction is complete, continue to add 200-300 parts of solution A to the system dropwise over a period of 0.5-2 hours. Step 5: After the droplet addition is complete, add 0.3 to 0.8 parts of initiator and continue the reaction for 2 to 4 hours. After the reaction is complete, wait for the system temperature to drop to room temperature, then add 2 to 8 parts of crosslinking monomer to the system and stir for 10 to 20 minutes to obtain the fluorine-free silicone high-temperature resistant protective film adhesive. Step 6: Weigh 10-30 parts of the prepared adhesive according to the mass ratio and coat it onto the PET. After coating, place it in a vacuum oven at 140-170℃ and dry for 5-10 minutes to obtain a fluorine-free silicone high-temperature resistant protective film.

2. The method for preparing the fluorine-free silicon high-temperature resistant protective film according to claim 1, characterized in that: In step one, the special monomer is an acrylonitrile monomer containing a double-bonded reactive group.

3. The method for preparing the fluorine-free silicon high-temperature resistant protective film according to claim 2, characterized in that: In step one, the acrylonitrile monomer containing a double-bonded reactive group is one of acrylonitrile, 3-cyclopentylacrylonitrile, or 3-phenylacrylonitrile.

4. The method for preparing the fluorine-free silicon high-temperature resistant protective film according to claim 1, characterized in that: In step five, the initiator is one or more of azobisisobutyronitrile, azobisisoheptanenitrile, and dicumyl peroxide.

5. The method for preparing the fluorine-free silicon high-temperature resistant protective film according to claim 1, characterized in that: In step five, the crosslinking monomer is a polyether-modified cyanate resin, a bisphenol A type cyanate resin, or a triazine type cyanate resin.

6. A fluorine-free silicon high-temperature resistant protective film obtained by the preparation method according to any one of claims 1 to 5.

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