Protective film for electronic mobile equipment and preparation method and terminal thereof

Abstract

The present application belongs to the field of protective films for electronic mobile devices, and in particular, relates to a protective film for electronic mobile devices, a preparation method thereof, and a terminal. The protective film for electronic mobile devices of the present application comprises a release layer, an adhesive layer, and a base layer stacked in sequence, wherein the base layer is mainly prepared from methyl methacrylate monomer, an initiator, MBS, acrylonitrile-styrene copolymer, and diphenyl phosphate. The present application greatly improves the mechanical properties while ensuring its transmittance by selecting materials for the base layer and adjusting the proportions of its components, and optimizing its process flow.

Description

Technical Field

[0001] The present application belongs to the technical field of protective films for electronic mobile devices, and in particular, relates to a protective film for electronic mobile devices, a preparation method thereof, and a terminal. Background Art

[0002] With the development of technology, touch-screen products such as mobile phones and tablet computers have become indispensable in people's lives. In order to prevent the touch screen from being scratched by other hard objects, most consumers will stick a layer of protective film on the touch screen.

[0003] In order to meet the needs of consumers and achieve better results, screen protectors for electronic devices are constantly being updated. The functions of screen protectors are no longer limited to scratch protection. Other properties such as light transmittance, hardness, and drop resistance are increasingly required. The materials used to make screen protectors have also evolved from the original PC (polycarbonate) film, PVC (polyvinyl chloride) film, and PET (polyethylene terephthalate) film to the current mainstream TPU film, tempered film, hydrogel film, etc.

[0004] The light transmittance and mechanical properties of existing protective films still need to be improved. Summary of the invention

[0005] The present application proposes a protective film for an electronic mobile device, a preparation method thereof, and a terminal, aiming to provide a protective film with high mechanical properties (such as surface hardness, tensile strength, elongation at break, etc.) and high light transmittance.

[0006] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0007] In a first aspect, the present application provides an electronic mobile device protective film, comprising a release layer, an adhesive layer and a base layer stacked in sequence, wherein the base layer is mainly made of the following raw materials:

[0008] Methyl methacrylate monomer;

[0009] An initiator, wherein the amount of the initiator added is 0.1% to 0.3% of the methyl methacrylate monomer;

[0010] MBS, wherein the addition amount of the MBS is 0-20% of the methyl methacrylate monomer;

[0011] Acrylonitrile-styrene copolymer, wherein the addition amount of the acrylonitrile-styrene copolymer is 5% to 15% of the methyl methacrylate monomer;

[0012] Diphenyl phosphate, wherein the addition amount of the diphenyl phosphate is 0-5% of the methyl methacrylate monomer.

[0013] In some possible implementations, the raw materials for preparing the base layer further include: divinylbenzene, and the added amount of the divinylbenzene is 0-0.2% of the methyl methacrylate monomer. At this time, the added amount of the acrylonitrile-styrene copolymer is 5%-8% of the methyl methacrylate monomer.

[0014] In some possible implementations, the material of the adhesive layer is selected from at least one of an organic silicone adhesive, an epoxy resin adhesive, and an acrylate adhesive.

[0015] In a second aspect, the present application provides a method for preparing an electronic mobile device protective film, which is used to prepare a substrate layer in the electronic mobile device protective film as described above, comprising the following preparation steps:

[0016] S1, adding an initiator to a methyl methacrylate monomer, dissolving, heating in a water bath, and cooling to obtain a methyl methacrylate monomer prepolymer slurry;

[0017] S2, adding acrylonitrile-styrene copolymer and MBS to the methyl methacrylate monomer prepolymer slurry, stirring and dissolving, and standing to obtain a first mixed slurry;

[0018] S3, adding diphenyl phosphate to the first mixed slurry, stirring evenly, to obtain a second mixed slurry;

[0019] S4, placing the second mixed slurry in a container for hot water bath polymerization, and obtaining a composite raw material after drying;

[0020] S5, extruding the composite material into a film through a single screw extruder to obtain a base layer;

[0021] S6, coating a bonding liquid on one surface of the base layer and drying the bonding liquid to form the adhesive layer, and attaching the release layer to a side of the adhesive layer away from the base layer.

[0022] In some possible implementations, before the step of "S4, placing the second mixed slurry in a container for water bath heating polymerization, and obtaining a composite material after drying", the step further includes: adding divinylbenzene to the second mixed slurry, stirring, and standing.

[0023] In some possible implementations, in the “S2, adding acrylonitrile-styrene copolymer and MBS to the methyl methacrylate monomer prepolymer slurry, stirring to dissolve, and letting stand to obtain a first mixed slurry”, the acrylonitrile-styrene copolymer and the MBS are melt-blended in a single-screw extruder and then added to the methyl methacrylate monomer prepolymer slurry, stirring to dissolve, and letting stand to obtain a first mixed slurry.

[0024] In some possible implementations, the rotation speed of the single-screw extruder is 450 r / min-600 r / min, and the temperature of the extruder head is 210° C.-220° C.

[0025] In some possible implementations, the added amount of MBS is 0-20% of the methyl methacrylate monomer, the added amount of acrylonitrile-styrene copolymer is 5%-15% of the methyl methacrylate monomer, and the added amount of diphenyl phosphate is 0-5% of the methyl methacrylate monomer.

[0026] In some possible implementations, the amount of MBS added is 0-20% of the methyl methacrylate monomer, the amount of acrylonitrile-styrene copolymer added is 5%-8% of the methyl methacrylate monomer, the amount of diphenyl phosphate added is 0-5% of the methyl methacrylate monomer, and the amount of divinyl benzene added is 0-0.2% of the methyl methacrylate monomer.

[0027] In a third aspect, the present application provides a terminal, comprising: the electronic mobile device protective film as described above, or the electronic mobile device protective film prepared by the aforementioned method for preparing the electronic mobile device protective film, and a main body; the release film of the electronic mobile device protective film is torn off and attached to the side of the main body that needs to be protected.

[0028] The base layer of the above-mentioned electronic mobile device protective film of the present application is mainly prepared from methyl methacrylate monomer, initiator, MBS, acrylonitrile-styrene copolymer and diphenyl phosphate. By adjusting the ratio of each component and its process flow, the mechanical properties are greatly improved while ensuring its transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 It is a cross-sectional schematic diagram of the protective film for electronic mobile equipment provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0033] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all mean: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b, c can be single or multiple.

[0034] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0035] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0036] Related parameters not specifically mentioned in the present application, such as temperature, stirring time, stirring speed, etc., represent that they can adopt conventional numerical parameters in the art.

[0037] The weight of the relevant components mentioned in the examples of the present specification can not only refer to the specific content of each component, but also indicate the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components in the examples of the present specification is proportionally enlarged or reduced, it is within the scope disclosed in the examples of the present specification. Specifically, the mass described in the examples of the present specification can be mass units known in the chemical industry such as µg, mg, g, and kg.

[0038] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0039] In a first aspect, the present application provides a protective film for an electronic mobile device, comprising a release layer 10, an adhesive layer 20 and a base layer 30 which are stacked in sequence, wherein the base layer 30 is mainly prepared from methyl methacrylate monomer, an initiator, MBS, an acrylonitrile-styrene copolymer and diphenyl phosphate, and the added amount of the initiator is 0.1% to 0.3% of the methyl methacrylate monomer, the added amount of MBS is 0 to 20% of the methyl methacrylate monomer, the added amount of the acrylonitrile-styrene copolymer is 5% to 15% of the methyl methacrylate monomer, and the added amount of the diphenyl phosphate is 0 to 5% of the methyl methacrylate monomer.

[0040] Exemplarily, the amount of the initiator added can be 0.1%, 0.13%, 0.15%, 0.18%, 0.2%, 0.22%, 0.25%, 0.27%, 0.28%, 0.3% of the methyl methacrylate monomer, or any typical but non-limiting point value or an interval value between any two point values, wherein the aforementioned 0.1% to 0.3% means including 0.1% and also including 0.3%.

[0041] Exemplarily, the addition amount of MBS can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% of the methyl methacrylate monomer, or any typical but non-limiting point value or an interval value between any two point values, but the addition amount of MBS is not 0, and the aforementioned 0-20% means not including 0 but including 20%.

[0042] Exemplarily, the addition amount of acrylonitrile-styrene copolymer can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% of the methyl methacrylate monomer, and other typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values, and the aforementioned 5-15% means including 5% and 15%.

[0043] Exemplarily, the addition amount of diphenyl phosphate can be 0.5%, 1%, 2%, 3%, 4%, 5%, etc. of the methyl methacrylate monomer, which is typical but not limiting, or an interval value between any two values. The aforementioned 0-5% means excluding 0 but including 5%.

[0044] The initiator may be AIBN or BPO, and the methyl methacrylate monomer and the initiator are bulk polymerized to form the methyl methacrylate monomer.

[0045] In some possible implementations, the raw material for preparing the base layer 30 also includes divinylbenzene, and the amount of divinylbenzene added is 0-0.2% of the methyl methacrylate monomer. In this case, the amount of acrylonitrile-styrene copolymer added needs to be controlled to be 5%-8% of the methyl methacrylate monomer. The addition of divinylbenzene and acrylonitrile-styrene copolymer can greatly improve the mechanical properties of the material, but will have a certain negative impact on its light transmittance. Therefore, it is necessary to strictly control the introduction content of divinylbenzene, and when the divinylbenzene raw material is introduced, the amount of acrylonitrile-styrene copolymer added needs to be appropriately reduced. Generally speaking, the more divinylbenzene is added, the less acrylonitrile-styrene copolymer should be added, and the two are inversely proportional.

[0046] At the same time, when divinylbenzene is introduced, the amount of MBS added should be greater than the amount of acrylonitrile-styrene copolymer added. At this time, the light transmittance of the material will not decrease due to the introduction of divinylbenzene. Some experimental data can be found in Table 1.

[0047] In some possible implementations, the material of the adhesive layer 20 is selected from at least one of a silicone adhesive, an epoxy resin adhesive, and an acrylate adhesive, among which acrylate adhesive is preferred because this adhesive has a stronger bonding ability and is not easily separated from the base layer 30 when peeled off, causing it to stick to the surface to be protected.

[0048] In a second aspect, the present application provides a method for preparing an electronic mobile device protective film, which is used to prepare the electronic mobile device protective film as described above, comprising the following preparation steps:

[0049] S1, adding an initiator to a methyl methacrylate monomer, dissolving, heating in a water bath, and cooling to obtain a methyl methacrylate monomer prepolymer slurry;

[0050] S2, adding acrylonitrile-styrene copolymer and MBS to the methyl methacrylate monomer prepolymer slurry, stirring and dissolving, and standing to obtain a first mixed slurry;

[0051] S3, adding diphenyl phosphate to the first mixed slurry, stirring evenly, to obtain a second mixed slurry;

[0052] S4, placing the second mixed slurry in a container for hot water bath polymerization, and obtaining a composite raw material after drying;

[0053] S5, extruding the composite raw material into a film through a single screw extruder to obtain a base layer 30;

[0054] S6, coating a bonding liquid on one surface of the base layer 30 and drying the bonding liquid to form the adhesive layer, and attaching the release layer 10 to the side of the adhesive layer facing away from the base layer 30.

[0055] Referring to Table 1, the preparation method of the present application for preparing the base layer 30 has at least the following beneficial effects:

[0056] Firstly, instead of directly using methyl methacrylate monomer as raw material, in-situ polymerization is used to form the methyl methacrylate monomer composite material, because the methyl methacrylate monomer composite material formed by in-situ polymerization has higher purity, and the raw materials can be closely blended before polymerization, thereby improving the quality of the finished product effect; secondly, the introduction of acrylonitrile-styrene copolymer itself can significantly improve the mechanical properties of the material; thirdly, the introduction of MBS can synergize with acrylonitrile-styrene copolymer to further optimize the mechanical properties of the material and effectively improve the toughness of the product, and controlling the addition amount of MBS and acrylonitrile-styrene copolymer can improve the toughness of the product without reducing the transmittance too much; fourthly, methyl methacrylate monomer is easy to absorb moisture during storage and use, resulting in warping, deformation, cracking and other phenomena, which have a fatal effect on the performance of methyl methacrylate monomer, and the addition of diphenyl phosphate can effectively reduce the water absorption rate of the product, thereby extending its service life or storage period, but its addition amount needs to be strictly controlled to avoid excessive addition leading to reduced transmittance.

[0057] In some possible implementations, the amount of MBS added is 0-20% of the methyl methacrylate monomer, the amount of acrylonitrile-styrene copolymer added is 5-15% of the methyl methacrylate monomer, and the amount of diphenyl phosphate added is 0-5% of the methyl methacrylate monomer. The content of acrylonitrile-styrene copolymer should not be too high, as it may easily weaken the toughness of the product.

[0058] In some possible implementations, before "S4, placing the second mixed slurry in a container for water bath heating polymerization, and drying to obtain a composite material", the method further includes: adding divinylbenzene to the second mixed slurry, stirring, and standing. Divinylbenzene is a cross-linking agent. When added before the hot water bath polymerization reaction occurs, it can effectively prevent the medium from being rapidly heated and causing implosion.

[0059] In some possible implementations, the amount of MBS added is 0-20% of the methyl methacrylate monomer, the amount of acrylonitrile-styrene copolymer added is 5%-8% of the methyl methacrylate monomer, the amount of diphenyl phosphate added is 0-5% of the methyl methacrylate monomer, and the amount of divinylbenzene added is 0-0.2% of the methyl methacrylate monomer. The introduction of divinylbenzene can significantly improve the mechanical properties of the material, but its dosage needs to be strictly controlled, and the amount of acrylonitrile-styrene copolymer added needs to be appropriately reduced. Generally speaking, the more divinylbenzene is added, the less acrylonitrile-styrene copolymer should be added, and the two are inversely proportional. Moreover, when divinylbenzene is introduced, it should be ensured that the amount of MBS added is greater than the amount of acrylonitrile-styrene copolymer added. At this time, the light transmittance of the material will not be reduced due to the introduction of divinylbenzene.

[0060] In some possible implementations, in the step “S2, adding acrylonitrile-styrene copolymer and MBS to the methyl methacrylate monomer prepolymer slurry, stirring to dissolve, and standing to obtain a first mixed slurry”, the acrylonitrile-styrene copolymer and the MBS are melt-blended by a single-screw extruder and then added to the methyl methacrylate monomer prepolymer slurry, stirring to dissolve, and standing to obtain a first mixed slurry. Melting the acrylonitrile-styrene copolymer and MBS before adding them to the prepolymer slurry is helpful for improving their mechanical properties.

[0061] In some possible implementations, the speed of the single screw extruder is 450 r / min to 600 r / min, and the extruder head temperature is 210° C. to 220° C. Within this speed and head temperature range, as the speed and head temperature increase, the impact strength of the material increases significantly, while the tensile strength decreases slightly.

[0062] In the third aspect, the present application provides a terminal, comprising: the electronic mobile device protective film as described above, or the electronic mobile device protective film prepared by the preparation method of the electronic mobile device protective film, and a main body; the release film of the electronic mobile device protective film is torn off and attached to the side of the main body that needs to be protected. The main body can be a smart phone, a tablet computer, an e-reader, a computer, etc., or even any household appliance or other electronic device with a screen display. Of course, the electronic mobile device protective film is not limited to being attached to the screen, but can also be attached to any place on the device that needs surface protection.

[0063] The base layer 30 of the above-mentioned electronic mobile device protective film of the present application is mainly prepared from methyl methacrylate monomer, initiator, MBS, acrylonitrile-styrene copolymer and diphenyl phosphate. By selecting the material of the base layer 30 and adjusting the proportion of its components and optimizing its process flow, the mechanical properties are greatly improved while ensuring its transmittance.

[0064] Example 1 to Example 7 and Comparative Example 1 to Comparative Example 4

[0065] Embodiments 1 to 7 and Comparative Examples 1 to 4 of the present application respectively provide a finished material of a base layer 30 in a protective film for an electronic mobile device. The raw material components and weight fractions used in each embodiment are shown in Table 1 below:

[0066] Table 1

[0067] Methyl Methacrylate Monomer Initiator MBS Acrylonitrile-styrene copolymer diphenyl phosphate Divinylbenzene Example 1 M 0.1%M 10%M 5%M 0 0 Example 2 M 0.3%M 10%M 10%M 0 0 Example 3 M 0.2%M 10%M 15%M 0 0 Example 4 M 0.2%M 10%M 10%M 5%M 0 Example 5 M 0.2%M 15%M 8%M 5%M 0.1%M Example 6 M 0.2%M 15%M 7%M 5%M 0.15%M Example 7 M 0.2%M 15%M 5%M 5%M 0.2%M Comparative Example 1 M 0.2%M 0 0 0 0 Comparative Example 2 M 0.2%M 10%M 20%M 0 0 Comparative Example 3 M 0.2%M 3%M 8%M 5 0.1%M Comparative Example 4 M 0.2%M 3%M 5%M 5 0.2%M

[0068] In order to verify the progress of the embodiments of the present application, the surface hardness, tensile strength, elongation at break, light transmittance and water absorption of the protective films for electronic mobile devices prepared in the above embodiments and comparative examples were tested respectively:

[0069] The water absorption rate is tested according to the test standard of ISO 62; the surface hardness is tested according to the test standard of GB / T 6739-86; the tensile strength is tested according to the test standard of ISO 527; the light transmittance is tested according to the test method of ISO 13468;

[0070] The test results are shown in Table 2 below:

[0071] Table 2

[0072] Transmittance / % Water absorption / % Surface hardness (pencil) / H Tensile strength / MPa Elongation at break / MPa Example 1 92 0.46 2H 87 7.5 Example 2 91 0.46 2H 87 7 Example 3 91 0.45 3H 86 8 Example 4 90 0.21 2H 88 8 Example 5 85 0.24 3H 87 9 Example 6 86 0.26 3H 88 8 Example 7 87 0.24 3H 88 9 Comparative Example 1 93 0.48 H 83 7 Comparative Example 2 88 0.42 3H 77 5 Comparative Example 3 77 0.23 3H 88 8 Comparative Example 4 79 0.23 3H 88 8

[0073] It should be noted that the above embodiments are only selected and displayed. As long as the raw materials are within the above-given ranges, the expected technical effects mentioned in this application can be achieved.

[0074] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A protective film for electronic mobile equipment, comprising a release layer, an adhesive layer and a base layer stacked in sequence, characterized in that: The substrate layer is mainly made of the following raw materials: Methyl methacrylate monomer; An initiator, wherein the amount of the initiator added is 0.1% to 0.3% of the methyl methacrylate monomer; MBS, wherein the addition amount of the MBS is 10-15% of the methyl methacrylate monomer; Acrylonitrile-styrene copolymer, wherein the addition amount of the acrylonitrile-styrene copolymer is 5% to 8% of the methyl methacrylate monomer; Diphenyl phosphate, wherein the addition amount of the diphenyl phosphate is 0-5% of the methyl methacrylate monomer, and the addition amount of the diphenyl phosphate is not 0; Divinylbenzene, wherein the added amount of the divinylbenzene is 0.1-0.2% of the methyl methacrylate monomer.

2. The protective film for electronic mobile equipment according to claim 1, characterized in that: The material of the adhesive layer is selected from at least one of organic silicone adhesive, epoxy resin adhesive and acrylate adhesive.

3. A method for preparing a protective film for an electronic mobile device, for preparing the protective film for an electronic mobile device as claimed in claim 1, characterized in that: The method comprises the following preparation steps: S1, adding an initiator to a methyl methacrylate monomer, dissolving, heating in a water bath, and cooling to obtain a methyl methacrylate monomer prepolymer slurry; S2, adding acrylonitrile-styrene copolymer and MBS to the methyl methacrylate monomer prepolymer slurry, stirring and dissolving, and standing to obtain a first mixed slurry; S3, adding diphenyl phosphate to the first mixed slurry, stirring evenly, to obtain a second mixed slurry; S4, placing the second mixed slurry in a container for hot water bath polymerization, and obtaining a composite raw material after drying; S5, extruding the composite material into a film through a single screw extruder to obtain a base layer; S6, applying an adhesive liquid on one surface of the base layer and drying the adhesive liquid to form the adhesive layer, and attaching the release layer to the side of the adhesive layer away from the base layer, thereby obtaining; Wherein, before the step of "S4, placing the second mixed slurry in a container for water bath heating polymerization, and drying to obtain a composite raw material", it also includes: adding divinylbenzene to the second mixed slurry, stirring, and standing.

4. The method for preparing a protective film for electronic mobile equipment according to claim 3, characterized in that: In the "S2, adding acrylonitrile-styrene copolymer and MBS to the methyl methacrylate monomer prepolymer slurry, stirring to dissolve, and standing to obtain a first mixed slurry", the acrylonitrile-styrene copolymer and the MBS are melt-blended by a single-screw extruder and then added to the methyl methacrylate monomer prepolymer slurry, stirring to dissolve, and standing to obtain a first mixed slurry.

5. The method for preparing a protective film for electronic mobile equipment according to claim 4, characterized in that: The rotation speed of the single screw extruder is 450 r / min-600 r / min, and the temperature of the extruder head is 210° C.-220° C.

6. A terminal, characterized in that: include: main body; An electronic mobile device protective film as claimed in any one of claims 1 to 2, or an electronic mobile device protective film prepared by the method for preparing an electronic mobile device protective film as claimed in any one of claims 3 to 5; The release film of the electronic mobile device protective film is torn off and attached to the side of the main body that needs to be protected.

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