Erasable film containing silica gel and preparation process thereof

Abstract

The invention relates to the technical field of erasable films, in particular to a silica gel-containing erasable film and a preparation process thereof. The erasable film containing the silica gel comprises a base film layer, an adhesive layer and a release layer which are sequentially arranged from top to bottom, the adhesive layer comprises the following materials in parts by weight: 60-70 parts of modified polyester resin, 25-35 parts of silica gel, 8-10 parts of tackifying resin, 5-7 parts of paraffin, 1-2 parts of an antioxidant, 0.5-1 part of a catalyst and 4-6 parts of filler. The prepared silica gel-containing erasable film not only has excellent protection performance, but also can realize rapid and traceless cleaning, effectively avoids the adhesion of stains, and improves the anti-aging performance to a certain extent.

Description

Technical Field

[0001] The invention relates to the technical field of erasable films, and in particular to an erasable film containing silica gel and a preparation process thereof. Background Art

[0002] With the continuous upgrading of modern office environment, the demand for the integration of various electronic devices and office furniture is growing. Among them, office whiteboards are important tools for team collaboration and information display, and the protection of their surfaces is becoming increasingly prominent. Although traditional whiteboard films can protect the surface of whiteboards to a certain extent, they still need to be improved in terms of wear resistance, weather resistance, easy cleaning and erasability. Therefore, the market urgently needs a high-performance protective film designed specifically for office whiteboards - erasable film.

[0003] Erasable films, especially erasable whiteboard films containing silicone, have become the new favorite of modern office spaces due to their excellent wear resistance, weather resistance, excellent easy cleaning and repeated erasing ability. As a high-performance material, silicone provides a solid material basis for erasable whiteboard films with its good elasticity, heat resistance, cold resistance, oxidation resistance and chemical stability. At the same time, the self-healing properties of silicone enable the whiteboard film to self-recover after slight damage, greatly extending its service life.

[0004] In the office environment, whiteboards are key places for meetings, discussions and creative inspiration. However, the surface of whiteboards is easily contaminated by stains such as marker marks, dust and fingerprints, which not only affects the appearance, but also may reduce the efficiency of whiteboard use. The erasable film containing silicone can not only effectively protect the surface of the whiteboard from scratches and stains, but also easily erase various marks while maintaining the clarity of the whiteboard, ensuring accurate communication of information.

[0005] However, existing erasable whiteboard films containing silicone on the market still have some problems, such as aging, discoloration, and edge degumming after long-term use, which affect the protective effect and service life of the whiteboard film. In addition, some whiteboard films may have problems of incomplete curing or poor weather resistance during the preparation process, which affects the user experience. Based on this, the present invention provides an erasable film containing silicone and a preparation process thereof. Summary of the invention

[0006] The purpose of the present invention is to provide an erasable film containing silica gel and a preparation process thereof, which not only has excellent protective performance and can achieve fast and traceless cleaning, but also improves the adhesion of the erasable film to a certain extent, reduces foaming during the film application process, and simultaneously achieves improved anti-aging performance.

[0007] In the first aspect, the present invention provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 60-70 parts of polyester resin, 25-35 parts of silicone, 8-10 parts of tackifying resin, 5-7 parts of paraffin, 1-2 parts of antioxidant, 0.5-1 parts of catalyst, and 4-6 parts of filler.

[0008] Furthermore, the base film layer is a transparent PET film with a thickness of 25-75 μm, and the thickness of the adhesive layer is 25-35 μm.

[0009] Furthermore, the tackifying resin includes C5 petroleum resin and / or C9 petroleum resin; the antioxidant includes at least one of antioxidant 168, antioxidant 1010 and antioxidant 1075; and the catalyst is dibutyltin dilaurate.

[0010] Furthermore, the filler comprises alumina-modified mica and calcined kaolin in a weight ratio of (4-6):(1-2).

[0011] Furthermore, the preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano-mica powder, and stirring at 90-100° C. for 1-2 hours to obtain the alumina-modified mica.

[0012] Furthermore, the weight ratio of the nano-mica powder, aluminate coupling agent, aluminum oxide and ethanol is 10:(1-2):(2-4):(14-16).

[0013] Furthermore, the preparation method of the calcined kaolin includes: calcining kaolin at 600-650° C. for 2-3 hours to obtain calcined kaolin; the particle size of the kaolin raw material is less than 325 mesh.

[0014] In a second aspect, the present invention provides a process for preparing an erasable film containing silicone, the steps comprising: mixing a formulated amount of adhesive layer raw materials, coating the adhesive layer on a base film layer by a coating machine, bonding a release layer after curing, rolling up, and ripening the film.

[0015] Furthermore, after coating, the coating is cured by being treated in an oven at a temperature of 80-110° C., and the speed of passing through the oven is 10-20 m / min.

[0016] Furthermore, the aging temperature is 50-60° C., and the aging time is 50-60 hours.

[0017] The beneficial effects of the present invention are:

[0018] The erasable film prepared in the present invention is writable and erasable on one side and adhesive-backed on the other side; the polyester resin in the raw material, as the main film-forming substance, has good adhesion and film-forming properties, and can ensure the close fit between the adhesive layer and the base film layer and the release layer. The addition of silica gel further enhances the flexibility and elasticity of the adhesive layer, so that it can better adapt to the surface morphology of different substrates and further improve the adhesion. C5 petroleum resin and / or C9 petroleum resin are used as tackifying resins to increase the interaction force between the adhesive layer and the adherend and improve the adhesion strength; these tackifying resins usually have a lower molecular weight and a higher polarity, and can form hydrogen bonds or van der Waals forces with polar groups on the surface of the substrate, thereby enhancing the adhesion effect.

[0019] In the present invention, alumina-modified mica and calcined kaolin are used as fillers, which can improve adhesion to a certain extent. Alumina and nano-mica powder are modified by aluminate coupling agent GR-AL18 to enhance the interaction between mica and the resin matrix. The enhancement of this interaction force helps to improve the adhesion between the adhesive layer and the base film layer and the surface of the object to be attached; the addition of alumina may increase the surface energy of the mica powder, making it easier to form a tight bond with the resin matrix, thereby further improving adhesion. Calcination treatment removes moisture and organic impurities in kaolin, improves its purity, and improves compatibility with the resin matrix; this improvement in compatibility helps to reduce the gaps between the interfaces and improve adhesion. And the calcined kaolin has a microporous structure, and these micropores can increase the contact area with the resin matrix like anchor points, thereby improving adhesion.

[0020] Furthermore, the uniform distribution of alumina-modified mica and calcined kaolin in the resin matrix helps to reduce stress concentration points inside the film layer, thereby reducing blistering caused by uneven stress during the film lamination process; the addition of fillers also improves the leveling of the adhesive layer, making it easier to form a uniform film layer during the coating process, reducing blistering caused by poor leveling.

[0021] In addition, alumina-modified mica enhances its compatibility with the resin matrix through the bridge effect of aluminate coupling agent GR-AL18. This improved compatibility helps to maintain a close bond between the filler and the resin under low temperature conditions and prevents interface separation caused by temperature reduction. Alumina is also a high-melting-point inorganic oxide that can significantly improve the thermal stability of the film layer. Under high temperature conditions, alumina can act as a thermal barrier to reduce the transfer of heat to the resin matrix, thereby delaying the thermal decomposition of the film layer. Nano-mica powder has a layered structure that can form a physical barrier in the resin matrix, reducing the movement of molecular segments at low temperatures, thereby maintaining the structural stability of the film layer. The calcined kaolin has a higher degree of crystallinity and a more stable structure, which can provide additional support in a low-temperature environment to prevent the film layer from cracking due to shrinkage or deformation. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is described clearly and completely below. 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] It should be noted that the polyester resin in the present invention is UP-RC511; the silica gel is type B silica gel, and the average pore size is Specific surface area 400-550m 2 / g, pore volume is 0.6-0.75mL / g; paraffin model is 66 paraffin; mica model is HP5 mica; kaolin model is SAP-200; montmorillonite model is K-10; attapulgite is purchased from Nanjing Bermuda Biotechnology Co., Ltd.

[0024] Example 1

[0025] The present embodiment provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.75 parts of catalyst, and 5 parts of filler;

[0026] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler includes alumina-modified mica and calcined kaolin in a weight ratio of 5:1.5;

[0027] The preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano-mica powder, and stirring at 95°C for 1.5 hours to obtain alumina-modified mica; the weight ratio of the nano-mica powder, aluminate coupling agent, alumina and ethanol is 10:1.5:3:15.

[0028] The preparation method of the calcined kaolin comprises: calcining kaolin at 625° C. for 2.5 hours to obtain calcined kaolin; and the particle size of the kaolin raw material is less than 325 meshes.

[0029] In this embodiment, a preparation process of an erasable film containing silicone comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on a base film layer by a coating machine, curing them in an oven at a temperature of 100°C, passing through the oven at a speed of 15m / min, and bonding a release layer after curing, rolling it up, and then curing it; the curing temperature is 55°C, and the curing time is 55h.

[0030] Example 2

[0031] The present embodiment provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 63 parts of polyester resin, 28 parts of silicone, 9 parts of tackifying resin, 5 parts of paraffin, 1 part of antioxidant, 1 part of catalyst, and 4 parts of filler;

[0032] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C9 petroleum resin; the antioxidant is antioxidant 1010; the catalyst is dibutyltin dilaurate; the filler includes alumina-modified mica and calcined kaolin in a weight ratio of 5:1;

[0033] The preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano-mica powder, and stirring at 90°C for 1 hour to obtain alumina-modified mica; the weight ratio of the nano-mica powder, aluminate coupling agent, alumina and ethanol is 10:1:3:14.

[0034] The preparation method of the calcined kaolin comprises: calcining kaolin at 620° C. for 2 hours to obtain calcined kaolin; and the particle size of the kaolin raw material is less than 325 meshes.

[0035] In this embodiment, a preparation process of an erasable film containing silicone comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on a base film layer by a coating machine, curing them by treating them in an oven at a temperature of 80°C, passing through the oven at a speed of 10m / min, and after curing, bonding a release layer, rolling it up, and curing it; the curing temperature is 50°C, and the curing time is 50h.

[0036] Example 3

[0037] The present embodiment provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 68 parts of polyester resin, 32 parts of silicone, 9 parts of tackifying resin, 7 parts of paraffin, 2 parts of antioxidant, 1 part of catalyst and 6 parts of filler;

[0038] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 1075; the catalyst is dibutyltin dilaurate; the filler includes alumina-modified mica and calcined kaolin in a weight ratio of 3:1;

[0039] The preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano-mica powder, and stirring at 100°C for 2 hours to obtain alumina-modified mica; the weight ratio of the nano-mica powder, aluminate coupling agent, alumina and ethanol is 10:2:4:16.

[0040] The preparation method of the calcined kaolin comprises: calcining kaolin at 650° C. for 2 hours to obtain calcined kaolin; and the particle size of the kaolin raw material is less than 325 meshes.

[0041] In this embodiment, a preparation process of an erasable film containing silicone comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on a base film layer by a coating machine, curing them by treating them in an oven at a temperature of 110°C, passing through the oven at a speed of 20m / min, and bonding a release layer after curing, rolling it up, and then curing it; the curing temperature is 60°C, and the curing time is 60h.

[0042] Example 4

[0043] The present embodiment provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.8 parts of catalyst, and 5 parts of filler;

[0044] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin includes C5 petroleum resin and / or C9 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler includes alumina-modified mica and calcined kaolin in a weight ratio of 3:1;

[0045] The preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano-mica powder, and stirring at 100°C for 1 hour to obtain alumina-modified mica; the weight ratio of the nano-mica powder, aluminate coupling agent, alumina and ethanol is 10:1.5:2.5:15.

[0046] The preparation method of the calcined kaolin comprises: calcining kaolin at 600-650° C. for 3 hours to obtain calcined kaolin; and the particle size of the kaolin raw material is less than 325 meshes.

[0047] In this embodiment, a preparation process of an erasable film containing silicone comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on a base film layer by a coating machine, curing them by oven treatment at a temperature of 110°C, passing through the oven at a speed of 10m / min, and bonding a release layer after curing, rolling it up, and then curing it; the curing temperature is 60°C, and the curing time is 60h.

[0048] Comparative Example 1

[0049] This comparative example provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.75 parts of catalyst, and 5 parts of filler;

[0050] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler includes manganese oxide modified mica and calcined kaolin in a weight ratio of 5:1.5;

[0051] The preparation method of the manganese oxide modified mica comprises: adding aluminate coupling agent GR-AL18, manganese oxide and ethanol to dry nano mica powder, and stirring at 95°C for 1.5 hours to obtain manganese oxide modified mica; the weight ratio of the nano mica powder, aluminate coupling agent, manganese oxide and ethanol is 10:1.5:3:15.

[0052] The preparation method of the calcined kaolin comprises: calcining kaolin at 625° C. for 2.5 hours to obtain calcined kaolin; and the particle size of the kaolin raw material is less than 325 meshes.

[0053] The preparation process of an erasable film containing silicone in this comparative example comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on the base film layer by a coating machine, curing them in an oven at a temperature of 100°C, passing through the oven at a speed of 15m / min, and bonding the release layer after curing, rolling it up, and then curing it; the curing temperature is 55°C, and the curing time is 55h.

[0054] Comparative Example 2

[0055] This comparative example provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.75 parts of catalyst, and 5 parts of filler;

[0056] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler includes zinc oxide modified mica and calcined kaolin in a weight ratio of 5:1.5;

[0057] The preparation method of the zinc oxide modified mica comprises: adding aluminate coupling agent GR-AL18, zinc oxide and ethanol to dry nano mica powder, and stirring at 95°C for 1.5 hours to obtain zinc oxide modified mica; the weight ratio of the nano mica powder, aluminate coupling agent, zinc oxide and ethanol is 10:1.5:3:15.

[0058] The preparation method of the calcined kaolin comprises: calcining kaolin at 625° C. for 2.5 hours to obtain calcined kaolin; and the particle size of the kaolin raw material is less than 325 meshes.

[0059] The preparation process of an erasable film containing silicone in this comparative example comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on the base film layer by a coating machine, curing them in an oven at a temperature of 100°C, passing through the oven at a speed of 15m / min, and bonding the release layer after curing, rolling it up, and then curing it; the curing temperature is 55°C, and the curing time is 55h.

[0060] Comparative Example 3

[0061] This comparative example provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.75 parts of catalyst, and 5 parts of filler;

[0062] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler includes mica and calcined kaolin in a weight ratio of 5:1.5;

[0063] The preparation method of the calcined kaolin comprises: calcining kaolin at 625° C. for 2.5 hours to obtain calcined kaolin; and the particle size of the kaolin raw material is less than 325 meshes.

[0064] The preparation process of an erasable film containing silicone in this comparative example comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on the base film layer by a coating machine, curing them in an oven at a temperature of 100°C, passing through the oven at a speed of 15m / min, and bonding the release layer after curing, rolling it up, and then curing it; the curing temperature is 55°C, and the curing time is 55h.

[0065] Comparative Example 4

[0066] This comparative example provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.75 parts of catalyst, and 5 parts of filler;

[0067] The base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler includes alumina-modified mica and kaolin in a weight ratio of 5:1.5;

[0068] The preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano-mica powder, and stirring at 95°C for 1.5 hours to obtain alumina-modified mica; the weight ratio of the nano-mica powder, aluminate coupling agent, alumina and ethanol is 10:1.5:3:15.

[0069] The particle size of the kaolin raw material is less than 325 mesh.

[0070] The preparation process of an erasable film containing silicone in this comparative example comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on the base film layer by a coating machine, curing them in an oven at a temperature of 100°C, passing through the oven at a speed of 15m / min, and bonding the release layer after curing, rolling it up, and then curing it; the curing temperature is 55°C, and the curing time is 55h.

[0071] Comparative Example 5

[0072] This comparative example provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.75 parts of catalyst, and 5 parts of filler;

[0073] The base film layer is a transparent PET film with a thickness of 50 μm, and the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler is alumina-modified mica; the preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano mica powder, and stirring at 95°C for 1.5 hours to obtain alumina-modified mica; the weight ratio of the nano mica powder, aluminate coupling agent, alumina and ethanol is 10:1.5:3:15.

[0074] The preparation process of an erasable film containing silicone in this comparative example comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on the base film layer by a coating machine, curing them in an oven at a temperature of 100°C, passing through the oven at a speed of 15m / min, and bonding the release layer after curing, rolling it up, and then curing it; the curing temperature is 55°C, and the curing time is 55h.

[0075] Comparative Example 6

[0076] This comparative example provides an erasable film containing silicone, comprising a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer comprises the following materials in parts by weight: 65 parts of polyester resin, 30 parts of silicone, 9 parts of tackifying resin, 6 parts of paraffin, 1.5 parts of antioxidant, 0.75 parts of catalyst, and 5 parts of filler;

[0077] Among them, the base film layer is a transparent PET film with a thickness of 50 μm, the thickness of the adhesive layer is 30 μm; the tackifying resin is C5 petroleum resin; the antioxidant is antioxidant 168; the catalyst is dibutyltin dilaurate; the filler is calcined kaolin; wherein the preparation method of the calcined kaolin includes: calcining kaolin at 625°C for 2.5 hours to obtain calcined kaolin; the particle size of the kaolin raw material is less than 325 mesh.

[0078] The preparation process of an erasable film containing silicone in this comparative example comprises the following steps: mixing the adhesive layer raw materials in a formulated amount, coating them on the base film layer by a coating machine, curing them in an oven at a temperature of 100°C, passing through the oven at a speed of 15m / min, and bonding the release layer after curing, rolling it up, and then curing it; the curing temperature is 55°C, and the curing time is 55h.

[0079] The erasable films prepared in Examples 1-4 and Comparative Examples 1-6 were tested:

[0080] 180 degree peeling force: refer to standard GBT-2792-2014, use universal tensile machine, measure each set of data 3 times, and take the average value;

[0081] High temperature aging resistance: Paste the prepared erasable film sample on a smooth steel plate, place it in an oven at 100°C for 2 hours, take it out and peel it off immediately while it is still hot, and observe whether there is any residue on the steel plate;

[0082] Low temperature aging resistance: The prepared erasable film sample was pasted on a smooth steel plate and placed in a frost-free refrigerator at -10°C for 5 hours. After taking it out, the adhesion state of the steel plate and the erasable film sample was observed; the test results are shown in Table 1.

[0083] Table 1 Test results

[0084]

[0085]

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. An erasable film containing silica gel, characterized in that: It includes a base film layer, an adhesive layer and a release layer arranged in sequence from top to bottom; the adhesive layer includes the following materials in parts by weight: 60-70 parts of polyester resin, 25-35 parts of silica gel, 8-10 parts of tackifying resin, 5-7 parts of paraffin, 1-2 parts of antioxidant, 0.5-1 parts of catalyst and 4-6 parts of filler.

2. The erasable film containing silica gel according to claim 1, characterized in that: The base film layer is a transparent PET film with a thickness of 25-75 μm, and the adhesive layer has a thickness of 25-35 μm.

3. The erasable film containing silica gel according to claim 1, characterized in that: The tackifying resin includes C5 petroleum resin and / or C9 petroleum resin; the antioxidant includes at least one of antioxidant 168, antioxidant 1010 and antioxidant 1075; and the catalyst is dibutyltin dilaurate.

4. The erasable film containing silica gel according to claim 1, characterized in that: The filler comprises alumina-modified mica and calcined kaolin in a weight ratio of (4-6):(1-2).

5. The erasable film containing silica gel according to claim 4, characterized in that: The preparation method of the alumina-modified mica comprises: adding aluminate coupling agent GR-AL18, alumina and ethanol to dry nano-mica powder, and stirring at 90-100° C. for 1-2 hours to obtain the alumina-modified mica.

6. The erasable film containing silica gel according to claim 5, characterized in that: The weight ratio of the nano-mica powder, the aluminate coupling agent, the aluminum oxide and the ethanol is 10:(1-2):(2-4):(14-16).

7. The erasable film containing silica gel according to claim 4, characterized in that: The preparation method of the calcined kaolin comprises: calcining kaolin at 600-650° C. for 2-3 hours to obtain calcined kaolin; the particle size of the kaolin raw material is less than 325 meshes.

8. A process for preparing an erasable film containing silica gel according to any one of claims 1 to 7, characterized in that the steps include: The adhesive layer raw materials in the formula amount are mixed, coated on the base film layer by a coating machine, and after curing, the release layer is attached, rolled up, and matured to obtain the product.

9. The process for preparing an erasable film containing silica gel according to claim 8, characterized in that: After coating, the coating is cured by being treated in an oven at a temperature of 80-110° C., and the speed of passing through the oven is 10-20 m / min.

10. The process for preparing an erasable film containing silica gel according to claim 8, characterized in that: The aging temperature is 50-60° C., and the aging time is 50-60 hours.

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