Double-sided antistatic silicone protective film for graphite sheet calendering and preparation method thereof

Abstract

The invention relates to the technical field of protective films, in particular to a double-sided antistatic silicone protective film for graphite sheet calendering and a preparation method thereof; the film comprises an outer antistatic layer, a substrate layer, an inner antistatic layer, a silicone pressure-sensitive adhesive layer and a release layer; the silicone pressure-sensitive adhesive layer comprises the following components, calculated by weight: 20 to 40 parts by weight of an organic silicone resin, 0.1 to 0.5 parts by weight of a cross-linking agent, 0.1 to 0.5 parts by weight of an anchoring agent, 0.1 to 0.5 parts by weight of a catalyst, 0.5 to 1.5 parts by weight of an ionic liquid, and 50 to 80 parts by weight of an organic solvent; the double-sided antistatic silicone protective film has a stable and moderate peeling force, which helps to reduce the problem of separation of the silicone protective film and a graphite sheet due to too low viscosity and powder loss of the graphite sheet when being torn off due to too high viscosity; and the double-sided antistatic silicone protective film has a double-sided antistatic coating, which can effectively reduce dust adsorption and damage caused by static electricity accumulation compared with a single-sided antistatic silicone protective film, and more comprehensively protect the graphite sheet.

Description

Technical Field

[0001] The invention relates to the technical field of protective films, in particular to a double-sided antistatic silicone protective film for graphite sheet calendering and a preparation method thereof. Background Art

[0002] Graphite sheet calendering is a material processing technology mainly used to produce thermally conductive graphite sheets. Due to its unique grain orientation and layered structure, it can conduct heat evenly in two directions and is widely used in the heat dissipation field of electronic products such as smartphones and tablets. In the process of graphite sheet calendering, the protective film plays multiple roles. During the processing, the protective film needs to provide appropriate adhesion for the graphite sheet. It is necessary to prevent the adhesion from being too low, causing the protective film to fall off the graphite sheet, and to prevent the adhesion from being too high, causing the graphite sheet to fall off or residual glue when the protective film is torn off. In addition, in the manufacture of electronic equipment, the protective film also needs to have certain anti-static properties to reduce the generation of static electricity, thereby protecting the graphite sheet from static damage.

[0003] Invention patent CN107151342A provides a double-sided antistatic protective film for graphite sheet calendering, which converts the hydroxyl groups inside nano-white carbon black into surface hydroxyl groups. The surface hydroxyl groups form hydrogen bonds with each other to form a conductive mechanism, thereby increasing the conductive properties of the protective film. However, the added nano-white carbon black has a high specific surface area and is prone to agglomeration, which affects the uniformity of the protective film. In addition, the addition of colored white carbon black will cause the light transmittance of the transparent protective film to decrease, thereby affecting the appearance of the protective film. Invention patent CN116218406A provides a graphite silicone protective film with stable peeling force. The protective film is coated with glue with a high storage modulus. The glue surface is not easy to deform, and the peeling force rises less. However, the protective film is a single-sided antistatic protective film, which cannot protect the graphite sheet from the influence of electrostatic adsorption more comprehensively than the double-sided antistatic protective film.

[0004] Based on this, the present invention provides a double-sided antistatic silicone protective film for graphite sheet calendering and a preparation method thereof to solve the above-mentioned technical problems. Summary of the invention

[0005] The purpose of the present invention is to provide a double-sided antistatic silicone protective film for calendering a graphite sheet and a preparation method thereof. The double-sided antistatic silicone protective film for calendering a double graphite sheet has a stable and moderate peeling force, which helps to reduce the problem of separation of the silicone protective film and the graphite sheet due to too low viscosity and powder loss of the graphite sheet when being torn off due to too high viscosity; and the double-sided antistatic silicone protective film for calendering a graphite sheet has a double-sided antistatic coating, which can effectively reduce dust adsorption and damage caused by static electricity accumulation compared with a single-sided antistatic silicone protective film, and more comprehensively protect the graphite sheet.

[0006] To achieve the above object, the present invention provides the following technical solutions: The first aspect of the present invention provides a double-sided antistatic silicone protective film for graphite sheet calendering, the double-sided antistatic silicone protective film comprising an outer antistatic layer, a substrate layer, an inner antistatic layer, a silicone pressure-sensitive adhesive layer and a release layer; The silicone pressure-sensitive adhesive layer comprises the following components calculated by weight: 20-40 parts by weight of organic silicon resin; Cross-linking agent 0.1-0.5 parts by weight; Anchoring agent 0.1-0.5 parts by weight; Catalyst 0.1-0.5 parts by mass; 0.5 to 1.5 parts by mass of ionic liquid; 50 to 80 parts by mass of organic solvent

[0007] The present invention is further configured as follows: the outer antistatic layer and the inner antistatic layer both comprise the following components calculated by weight: 20-30 parts by weight of low-density polyethylene; 5 to 8 parts by mass of maleic anhydride; 1 to 5 parts by weight of dicumyl peroxide; 2-4 parts by weight of composite antistatic agent; The preparation processes of the outer antistatic layer and the inner antistatic layer are as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent, place low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent in a mixing device, and mix at 500-1000 r / min for 20-30 min; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.5 to 2:1.

[0008] The present invention is further configured as follows: the organic silicone resin is one or more combinations of MQ organic silicone resins consisting of monofunctional groups and tetrafunctional groups.

[0009] The present invention is further configured as follows: the MQ silicone resin is one of methyl MQ silicone resin, vinyl MQ silicone resin, hydrogen-containing MQ silicone resin, phenyl MQ silicone resin, and fluorine-containing MQ silicone resin.

[0010] The present invention is further configured as follows: the crosslinking agent is one of hydrogen-containing siloxane, vinyl siloxane, epoxy siloxane, amino siloxane, and organic peroxide.

[0011] The present invention is further configured as follows: the anchoring agent is an organic silicon compound, which includes a functionalized organic siloxane compound containing vinyl groups and epoxy groups.

[0012] The present invention is further configured as follows: the organic siloxane compound is a polymeric anchoring agent, which is composed of oligomeric alkenyl siloxane and / or high molecular weight epoxy polysiloxane.

[0013] The present invention is further configured as follows: the catalyst is one of a metal catalyst, an organic peroxide catalyst and an inorganic catalyst.

[0014] The present invention is further configured as follows: the ionic liquid is one of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate, lauryl amide propyl trimethylamine, and dodecyl imidazoline quaternary ammonium salt.

[0015] The present invention is further configured as follows: the substrate layer is selected from any one of polyethylene terephthalate (PET) film, polyethylene (PE) film, and polypropylene (PP) film.

[0016] The present invention is further configured as follows: the release layer is selected from any one of polyethylene terephthalate (PET) film and polypropylene (PP) film.

[0017] The present invention is further configured as follows: the organic solvent is toluene.

[0018] The second aspect of the present invention is to provide a method for preparing the above-mentioned double-sided antistatic silicone protective film for graphite sheet calendering, comprising the following steps: Step 1: Compounding the outer antistatic layer and the inner antistatic layer on both sides of the single-sided corona substrate layer to form a double-sided antistatic film; Step 2: Mix and stir the silicone resin, cross-linking agent, anchoring agent, catalyst, ionic liquid and organic solvent evenly, apply a silicone pressure-sensitive adhesive layer on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 5 to 10 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer at 130 to 150° C. for 10 to 20 minutes, and compound a release film on the obtained silicone pressure-sensitive adhesive layer to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering.

[0019] Compared with the prior art, the present invention has the following beneficial effects: The present invention comprises an outer antistatic layer, a substrate layer, an inner antistatic layer, a silicone pressure-sensitive adhesive layer and a release layer; wherein the silicone pressure-sensitive adhesive layer is made of organic silicone resin, a crosslinking agent, an anchoring agent, a catalyst, an ionic liquid, an organic solvent, etc. The double-sided antistatic silicone protective film for double-graphite sheet calendering provided by the present invention has a stable and moderate peeling force, which helps to reduce the problem of separation of the silicone protective film and the graphite sheet due to too low viscosity and the problem of graphite sheet powder falling off when being torn off due to too high viscosity; and the double-sided antistatic silicone protective film for graphite sheet calendering has a double-sided antistatic coating, which can effectively reduce dust adsorption and damage caused by static electricity accumulation compared with a single-sided antistatic silicone protective film, and more comprehensively protect the graphite sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic structural diagram of a double-sided antistatic silicone protective film for graphite sheet calendering.

[0021] Description of Figure Numbers: 1. External antistatic layer; 2. Base material layer; 3. Internal antistatic layer; 4. Silicone pressure-sensitive adhesive layer; 5. Release layer. DETAILED DESCRIPTION

[0022] 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.

[0023] The present invention provides a double-sided antistatic silicone protective film for graphite sheet calendering, wherein the double-sided antistatic silicone protective film comprises an outer antistatic layer, a substrate layer, an inner antistatic layer, a silicone pressure-sensitive adhesive layer and a release layer; The silicone pressure-sensitive adhesive layer comprises the following components calculated by weight: 20-40 parts by weight of organic silicon resin; Cross-linking agent 0.1-0.5 parts by weight; Anchoring agent 0.1-0.5 parts by weight; Catalyst 0.1-0.5 parts by mass; 0.5 to 1.5 parts by mass of ionic liquid; 50 to 80 parts by mass of organic solvent

[0024] The outer antistatic layer and the inner antistatic layer both include the following components calculated by weight: 20-30 parts by weight of low-density polyethylene; 5 to 8 parts by mass of maleic anhydride; 1 to 5 parts by weight of dicumyl peroxide; 2-4 parts by weight of composite antistatic agent; The preparation processes of the outer antistatic layer and the inner antistatic layer are as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent, place low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent in a mixing device, and mix at 500-1000 r / min for 20-30 min; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.5 to 2:1.

[0025] In some embodiments, the silicone resin is one or more combinations of MQ silicone resins composed of monofunctional groups and tetrafunctional groups. Preferably, the MQ silicone resin is methyl MQ silicone resin, vinyl MQ silicone resin, hydrogen-containing MQ silicone resin, phenyl MQ silicone resin, and fluorine-containing MQ silicone resin. MQ silicone resin has a double-layer structure of a compact spherical body, the core of the sphere is connected by Si-O chains and has a high density, and the shell is composed of a lower-density R3SiO1 / 2 layer. The cage-like structure with a high degree of polymerization provides excellent mechanical properties and heat resistance for the silicone protective film.

[0026] In some embodiments, the crosslinking agent is one of hydrogen-containing siloxane, vinyl siloxane, epoxy siloxane, amino siloxane, and organic peroxides, such as benzoyl peroxide and 2,4-dichlorobenzoyl peroxide. The crosslinking agent provides the silicone pressure-sensitive adhesive with high-temperature adhesion and aging resistance.

[0027] In some embodiments, the anchoring agent is an organosilicon compound, including a functionalized organosiloxane compound containing vinyl and epoxy groups; a polymeric anchoring agent, including oligomeric alkenyl siloxane and / or high molecular weight epoxy polysiloxane. The anchoring agent forms a strong chemical bond with the surface of the substrate through specific functional groups in its molecular structure, such as vinyl, epoxy, alkoxy and other groups, thereby improving the bonding performance of the silicone material and enhancing the application effect and service life of the silicone protective film.

[0028] In some embodiments, the catalyst is a metal catalyst, an organic peroxide catalyst, or an inorganic catalyst. The catalyst connects some molecules of the silicone resin through the mutual condensation reaction of silanol groups, thereby improving the cohesion of the silicone pressure-sensitive adhesive. Preferably, the metal catalyst is a noble metal catalyst such as platinum, palladium, and silver, which promotes the addition reaction between silicon-hydrogen bonds (Si-H) and vinyl (Si-Vi) or hydrogen functional groups to form stable silicon-oxygen bonds (Si-O-Si), which helps to improve the selectivity of the reaction and reduce the occurrence of side reactions, thereby improving the stability of the silicone pressure-sensitive adhesive.

[0029] In some embodiments, the ionic liquid is one of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate, lauryl amide propyl trimethylamine, and dodecyl imidazoline quaternary ammonium salt. The positively charged quaternary ammonium cations in the ionic liquid neutralize the negatively charged static charge on the surface of the silicone pressure-sensitive adhesive, thereby reducing the accumulation of static electricity.

[0030] In addition, this embodiment also provides a method for preparing the above-mentioned double-sided antistatic silicone protective film for graphite sheet calendering, comprising the following steps: Step 1: Compounding the outer antistatic layer and the inner antistatic layer on both sides of the single-sided corona substrate layer to form a double-sided antistatic film; Step 2: Mix and stir the silicone resin, cross-linking agent, anchoring agent, catalyst, ionic liquid and organic solvent evenly, apply a silicone pressure-sensitive adhesive layer on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 5 to 10 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer at 130 to 150° C. for 10 to 20 minutes, and compound a release film on the obtained silicone pressure-sensitive adhesive layer to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering. Example

[0031] like Figure 1 As shown, this embodiment provides a double-sided antistatic silicone protective film for graphite sheet calendering, and the double-sided antistatic silicone protective film includes an outer antistatic layer 1, a substrate layer 2, an inner antistatic layer 3, a silicone pressure-sensitive adhesive layer 4 and a release layer 5; The silicone pressure-sensitive adhesive layer 4 comprises the following components in parts by weight: 40 parts by mass of methyl MQ silicone resin; 0.3 parts by mass of aminosilicone; 0.2 parts by mass of organosiloxane; 0.2 parts by mass of platinum catalyst; 1 part by mass of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate; 50 parts by mass of toluene.

[0032] The outer antistatic layer and the inner antistatic layer both include the following components calculated by weight: 20 parts by mass of low-density polyethylene; 5 parts by mass of maleic anhydride; 1 part by mass of dicumyl peroxide; 2 parts by mass of composite antistatic agent; The preparation process of the outer antistatic layer and the inner antistatic layer is as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and a composite antistatic agent, place the low-density polyethylene, maleic anhydride, dicumyl peroxide and the composite antistatic agent in a mixing device, and mix them at 500 r / min for 20 minutes; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.5:1.

[0033] In this embodiment, it should be noted that the low-density polyethylene was purchased from Dongguan Weicai Plastic Raw Materials Co., Ltd.

[0034] In addition, this embodiment also provides a method for preparing the above-mentioned double-sided antistatic silicone protective film for graphite sheet calendering, comprising the following steps: Step 1: Compounding the outer antistatic layer 1 and the inner antistatic layer 3 on both sides of the single-sided corona substrate layer 2 to form a double-sided antistatic film; Step 2: Mix and stir methyl MQ silicone resin, aminosiloxane, organic siloxane, platinum catalyst, octadecane dimethyl hydroxyethyl quaternary ammonium nitrate and toluene, apply a silicone pressure-sensitive adhesive layer 4 on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 5 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer 4 at 130°C for 10 minutes, and compound a release film 5 on the obtained silicone pressure-sensitive adhesive layer 4 to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering. Example

[0035] like Figure 1 As shown, this embodiment provides a double-sided antistatic silicone protective film for graphite sheet calendering, and the double-sided antistatic silicone protective film includes an outer antistatic layer 1, a substrate layer 2, an inner antistatic layer 3, a silicone pressure-sensitive adhesive layer 4 and a release layer 5; The silicone pressure-sensitive adhesive layer 4 comprises the following components in parts by weight: 35 parts by mass of methyl MQ silicone resin; 5 parts by mass of hydrogenated MQ silicone resin; 0.3 parts by mass of aminosilicone; 0.2 parts by mass of organosiloxane; 0.2 parts by mass of platinum catalyst; 1 part by mass of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate; 50 parts by mass of toluene.

[0036] The outer antistatic layer and the inner antistatic layer both include the following components calculated by weight: 22 parts by mass of low-density polyethylene; Maleic anhydride 6 parts by mass; 2 parts by mass of dicumyl peroxide; 3 parts by mass of composite antistatic agent; The preparation process of the outer antistatic layer and the inner antistatic layer is as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and a composite antistatic agent, place the low-density polyethylene, maleic anhydride, dicumyl peroxide and the composite antistatic agent in a mixing device, and mix them at 600 r / min for 22 minutes; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.7:1.

[0037] In this embodiment, it should be noted that the low-density polyethylene was purchased from Dongguan Weicai Plastic Raw Materials Co., Ltd.

[0038] In addition, this embodiment also provides a method for preparing the above-mentioned double-sided antistatic silicone protective film for graphite sheet calendering, comprising the following steps: Step 1: Mix and stir methyl MQ silicone resin, hydrogen-containing MQ silicone resin, aminosiloxane, organic siloxane, platinum catalyst, octadecane dimethyl hydroxyethyl quaternary ammonium nitrate and toluene, apply a silicone pressure-sensitive adhesive layer 4 on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 6 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer 4 at 132° C. for 11 min, and compound a release film 5 on the obtained silicone pressure-sensitive adhesive layer 4 to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering. Example

[0039] like Figure 1 As shown, this embodiment provides a double-sided antistatic silicone protective film for graphite sheet calendering, and the double-sided antistatic silicone protective film includes an outer antistatic layer 1, a substrate layer 2, an inner antistatic layer 3, a silicone pressure-sensitive adhesive layer 4 and a release layer 5; The silicone pressure-sensitive adhesive layer 4 comprises the following components in parts by weight: 30 parts by mass of methyl MQ silicone resin; 10 parts by mass of hydrogenated MQ silicone resin; 0.3 parts by mass of aminosilicone; 0.2 parts by mass of organosiloxane; 0.2 parts by mass of platinum catalyst; 1 part by mass of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate; 50 parts by mass of toluene.

[0040] The outer antistatic layer and the inner antistatic layer both include the following components calculated by weight: 25 parts by mass of low-density polyethylene; Maleic anhydride 7 parts by mass; 3 parts by mass of dicumyl peroxide; 3 parts by mass of composite antistatic agent; The preparation process of the outer antistatic layer and the inner antistatic layer is as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent, place low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent in a mixing device, and mix at 750 r / min for 25 min; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.7:1.

[0041] In this embodiment, it should be noted that the low-density polyethylene was purchased from Dongguan Weicai Plastic Raw Materials Co., Ltd.

[0042] In addition, this embodiment also provides a method for preparing the above-mentioned double-sided antistatic silicone protective film for graphite sheet calendering, comprising the following steps: Step 1: Compounding the outer antistatic layer 1 and the inner antistatic layer 3 on both sides of the single-sided corona substrate layer 2 to form a double-sided antistatic film; Step 2: Mix and stir methyl MQ silicone resin, hydrogen-containing MQ silicone resin, aminosiloxane, organic siloxane, platinum catalyst, octadecane dimethyl hydroxyethyl quaternary ammonium nitrate and toluene, apply a silicone pressure-sensitive adhesive layer 4 on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 7 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer 4 at 140°C for 15 minutes, and compound a release film 5 on the obtained silicone pressure-sensitive adhesive layer 4 to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering. Example

[0043] like Figure 1 As shown, this embodiment provides a double-sided antistatic silicone protective film for graphite sheet calendering, and the double-sided antistatic silicone protective film includes an outer antistatic layer 1, a substrate layer 2, an inner antistatic layer 3, a silicone pressure-sensitive adhesive layer 4 and a release layer 5; The silicone pressure-sensitive adhesive layer 4 comprises the following components in parts by weight: 25 parts by mass of methyl MQ silicone resin; 15 parts by mass of hydrogenated MQ silicone resin; 0.3 parts by mass of aminosilicone; 0.2 parts by mass of organosiloxane; 0.2 parts by mass of platinum catalyst; 1 part by mass of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate; 50 parts by mass of toluene.

[0044] The outer antistatic layer and the inner antistatic layer both include the following components calculated by weight: 28 parts by mass of low-density polyethylene; Maleic anhydride 7 parts by mass; 4 parts by mass of dicumyl peroxide; 3 parts by mass of composite antistatic agent; The preparation process of the outer antistatic layer and the inner antistatic layer is as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and a composite antistatic agent, place the low-density polyethylene, maleic anhydride, dicumyl peroxide and the composite antistatic agent in a mixing device, and mix them at 900 r / min for 28 minutes; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.8:1.

[0045] In this embodiment, it should be noted that the low-density polyethylene was purchased from Dongguan Weicai Plastic Raw Materials Co., Ltd.

[0046] In addition, this embodiment also provides a method for preparing the above-mentioned double-sided antistatic silicone protective film for graphite sheet calendering, comprising the following steps: Step 1: Compounding the outer antistatic layer 1 and the inner antistatic layer 3 on both sides of the single-sided corona substrate layer 2 to form a double-sided antistatic film; Step 2: Mix and stir methyl MQ silicone resin, hydrogen-containing MQ silicone resin, aminosiloxane, organic siloxane, platinum catalyst, octadecane dimethyl hydroxyethyl quaternary ammonium nitrate and toluene, apply a silicone pressure-sensitive adhesive layer 4 on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 9 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer 4 at 145°C for 18 minutes, and compound a release film 5 on the obtained silicone pressure-sensitive adhesive layer 4 to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering. Example

[0047] like Figure 1 As shown, this embodiment provides a double-sided antistatic silicone protective film for graphite sheet calendering, and the double-sided antistatic silicone protective film includes an outer antistatic layer 1, a substrate layer 2, an inner antistatic layer 3, a silicone pressure-sensitive adhesive layer 4 and a release layer 5; The silicone pressure-sensitive adhesive layer 4 comprises the following components in parts by weight: 20 parts by mass of methyl MQ silicone resin; 20 parts by mass of hydrogenated MQ silicone resin; 0.3 parts by mass of aminosilicone; 0.2 parts by mass of organosiloxane; 0.2 parts by mass of platinum catalyst; 1 part by mass of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate; 50 parts by mass of toluene.

[0048] The outer antistatic layer and the inner antistatic layer both include the following components calculated by weight: 30 parts by mass of low-density polyethylene; 8 parts by mass of maleic anhydride; 5 parts by mass of dicumyl peroxide; 4 parts by weight of composite antistatic agent; The preparation process of the outer antistatic layer and the inner antistatic layer is as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and a composite antistatic agent, place the low-density polyethylene, maleic anhydride, dicumyl peroxide and the composite antistatic agent in a mixing device, and mix them at 1000 r / min for 30 minutes; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.5 to 2:1.

[0049] In this embodiment, it should be noted that the low-density polyethylene was purchased from Dongguan Weicai Plastic Raw Materials Co., Ltd.

[0050] In addition, this embodiment also provides a method for preparing the above-mentioned double-sided antistatic silicone protective film for graphite sheet calendering, comprising the following steps: Step 1: Compounding the outer antistatic layer 1 and the inner antistatic layer 3 on both sides of the single-sided corona substrate layer 2 to form a double-sided antistatic film; Step 2: Mix and stir methyl MQ silicone resin, hydrogen-containing MQ silicone resin, aminosiloxane, organic siloxane, platinum catalyst, octadecane dimethyl hydroxyethyl quaternary ammonium nitrate and toluene, apply a silicone pressure-sensitive adhesive layer 4 on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 10 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer 4 at 150°C for 20 minutes, and compound a release film 5 on the obtained silicone pressure-sensitive adhesive layer 4 to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering.

[0051] Comparative Example 1: The difference from Example 1 is that the silicone pressure-sensitive adhesive layer includes the following components calculated by weight: 30 parts by mass of methyl MQ silicone resin; 10 parts by mass of hydrogenated MQ silicone resin; 0.2 parts by mass of organosiloxane; 0.2 parts by mass of platinum catalyst; 1 part by mass of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate; 50 parts by mass of toluene.

[0052] Comparative Example 2: The difference from Example 1 is that the silicone pressure-sensitive adhesive layer includes the following components calculated by weight: 30 parts by mass of methyl MQ silicone resin; 10 parts by mass of hydrogenated MQ silicone resin; 0.3 parts by mass of aminosilicone; 0.2 parts by mass of platinum catalyst; 1 part by mass of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate; 50 parts by mass of toluene.

[0053] Comparative Example 3: The difference from Example 1 is that the silicone pressure-sensitive adhesive layer includes the following components calculated by weight: 30 parts by mass of methyl MQ silicone resin; 10 parts by mass of hydrogenated MQ silicone resin; 0.3 parts by mass of aminosilicone; 0.2 parts by mass of organosiloxane; 0.2 parts by mass of platinum catalyst; 50 parts by mass of toluene.

[0054] Performance test: The double-sided antistatic silicone protective film samples for graphite sheet calendering provided in Examples 1 to 5 and Comparative Examples 1 to 3 are marked as Examples 1 to 5 and Comparative Examples 1 to 3, respectively; and the relevant properties of the double-sided antistatic silicone protective film for graphite sheet calendering provided in Examples 1 to 5 and Comparative Examples 1 to 3 are tested as follows: 1. Peel strength test: The test method is in accordance with the national standard GB / T 2792-2014 "Test method for peel strength of adhesive tape", and the test object is a graphite sheet.

[0055] 2. Peel force climbing test: The test method is to cut the prepared silicone protective film into samples with a size of 15cm*2.5cm, peel off the release film and stick it on the graphite sheet, place it in a 70℃ oven, take it out after 72 hours, place it in a 23℃ / 50%RH environment for 2 hours to return to temperature, and pull the protective film to test its 180° peel force on the graphite sheet.

[0056] 3. Film tearing voltage test: The test method is to measure according to the national standard GB / T 33375-2016 "Test method for electrostatic properties of adhesive tapes". Cut the produced silicone protective film into samples of 8cm*15cm size, place them in an environment of 23℃ / 50%RH for 2 hours, and stick them on the glass test board after the release film is torn off. Fix the film tearing voltage tester TREK520 on the machine, keep the probe 10cm away from the test glass board, and the tester wears anti-static gloves and wristbands, peels the silicone protective film from the glass test board at a speed of 20cm / s, and records the film tearing static voltage.

[0057] 4. Light transmittance / haze test: The test method is in accordance with the national standard GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics".

[0058] The following Tables 1 and 2 list the specific raw material formulations and product test data of different embodiments and comparative examples.

[0059]

[0060]

[0061] By comparing and analyzing the relevant data in Table 1 and Table 2, it can be seen that the double-sided antistatic silicone protective film for graphite sheet calendering provided by the present invention has a stable and moderate peeling force, which helps to reduce the separation of the silicone protective film and the graphite sheet due to too low viscosity and the problem of graphite sheet powder falling off when being torn off due to too high viscosity; and the double-sided antistatic silicone protective film for graphite sheet calendering has a double-sided antistatic coating, which can effectively reduce dust adsorption and damage caused by static electricity accumulation compared with the single-sided antistatic silicone protective film, and more comprehensively protect the graphite sheet. This shows that the double-sided antistatic silicone protective film for graphite sheet calendering provided by the present invention and its preparation method have a broader market prospect and are more suitable for promotion.

[0062] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0063] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A double-sided antistatic silicone protective film for graphite sheet calendering, characterized in that: The double-sided antistatic silicone protective film comprises an outer antistatic layer, a substrate layer, an inner antistatic layer, a silicone pressure-sensitive adhesive layer and a release layer; The silicone pressure-sensitive adhesive layer comprises the following components calculated by weight: 20-40 parts by weight of organic silicon resin; Cross-linking agent 0.1-0.5 parts by weight; Anchoring agent 0.1-0.5 parts by weight; Catalyst 0.1-0.5 parts by mass; 0.5 to 1.5 parts by mass of ionic liquid; 50 to 80 parts by mass of organic solvent 2. The double-sided antistatic silicone protective film for graphite sheet calendering according to claim 1, characterized in that: The outer antistatic layer and the inner antistatic layer both include the following components in parts by weight: 20-30 parts by weight of low-density polyethylene; 5 to 8 parts by mass of maleic anhydride; 1 to 5 parts by weight of dicumyl peroxide; 2-4 parts by weight of composite antistatic agent; The preparation processes of the outer antistatic layer and the inner antistatic layer are as follows: Accurately weigh low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent, place low-density polyethylene, maleic anhydride, dicumyl peroxide and composite antistatic agent in a mixing device, and mix at 500-1000 r / min for 20-30 min; After the mixing is completed, the mixture is placed in a twin-screw extruder for mixing and extrusion, and a film is prepared by film blowing and cast molding processes; The composite antistatic agent is prepared by mixing ethoxylated alkylamine and polyethylene glycol glycidyl ether in a mass ratio of 1.5 to 2:

1.

3. The double-sided antistatic silicone protective film for graphite sheet calendering according to claim 1, characterized in that: The organic silicone resin is one or more combinations of MQ organic silicone resins consisting of monofunctional groups and tetrafunctional groups.

4. The double-sided antistatic silicone protective film for graphite sheet calendering according to claim 3, characterized in that: The MQ silicone resin is one of methyl MQ silicone resin, vinyl MQ silicone resin, hydrogen-containing MQ silicone resin, phenyl MQ silicone resin, and fluorine-containing MQ silicone resin.

5. The double-sided antistatic silicone protective film for graphite sheet calendering according to claim 1, characterized in that: The crosslinking agent is one of hydrogen-containing siloxane, vinyl siloxane, epoxy siloxane, amino siloxane, and organic peroxide, such as benzoyl peroxide and 2,4-dichlorobenzoyl peroxide.

6. The double-sided antistatic silicone protective film for graphite sheet calendering according to claim 1, characterized in that: The anchoring agent is an organic silicon compound, which includes a functionalized organic siloxane compound containing vinyl and epoxy groups.

7. The double-sided antistatic silicone protective film for graphite sheet calendering according to claim 6, characterized in that: The organic siloxane compound is a polymeric anchoring agent, which is composed of oligomeric alkenyl siloxane and / or high molecular weight epoxy polysiloxane.

8. The double-sided antistatic silicone protective film for graphite sheet calendering according to claim 1, characterized in that: The ionic liquid is one of octadecane dimethyl hydroxyethyl quaternary ammonium nitrate, lauryl amide propyl trimethylamine, and dodecyl imidazoline quaternary ammonium salt.

9. The method for preparing a double-sided antistatic silicone protective film for graphite sheet calendering according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: Compounding the outer antistatic layer and the inner antistatic layer on both sides of the single-sided corona substrate layer to form a double-sided antistatic film; Step 2: Mix and stir the silicone resin, cross-linking agent, anchoring agent, catalyst, ionic liquid and organic solvent evenly, apply a silicone pressure-sensitive adhesive layer on the double-sided antistatic film prepared in step 1, and pull the double-sided antistatic film at a speed of 5 to 10 mm / s; bake the double-sided antistatic film coated with the silicone pressure-sensitive adhesive layer at 130 to 150° C. for 10 to 20 minutes, and compound a release film on the obtained silicone pressure-sensitive adhesive layer to finally obtain a finished double-sided antistatic silicone protective film for graphite sheet calendering.

Images