Composite material and preparation method therefor

Abstract

The present application discloses a composite material and a preparation method therefor, belonging to the field of organic materials. The composite material comprises: a transparent substrate layer and a first protective layer stacked on the transparent substrate layer. The raw materials for preparing the transparent substrate layer comprise a base material, an ultraviolet absorber and an antioxidant; the raw material for preparing the first protective layer is selected from at least one of a multifunctional acrylic resin, an epoxy-modified acrylic resin, a polyurethane-modified acrylic resin, a fluoropolyether-modified acrylic resin, a polysiloxane resin, an epoxy resin and a polyurethane resin. The composite material not only has excellent resistance to ultraviolet yellowing, but also has excellent resistance to yellowing due to dirt.

Description

Composite material and preparation method thereof

[0001] This application claims priority to Chinese patent application No. 202310767734.1, filed on June 26, 2023, entitled “Composite Materials and Methods for Preparing Them,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to the field of organic materials, and in particular to composite materials and methods for preparing the same. Background Art

[0003] Transparent mobile phone protective cases can not only protect the phone, but also show the material and design of the phone itself. TPU (Thermoplastic Urethane) is commonly used to prepare transparent protective cases due to its high transparency and low hardness.

[0004] However, transparent protective cases made of TPU material are prone to irreversible yellowing after a certain period of use, which affects the user experience. Therefore, it is necessary to improve the yellowing resistance of transparent protective cases.

[0005] Public content

[0006] In view of this, the present disclosure provides a composite material and a preparation method thereof, which can solve the technical problem in the related art that the transparent protective cover has poor yellowing resistance.

[0007] Specifically, the following technical solutions are included:

[0008] In one aspect, a composite material is provided, comprising: a transparent substrate layer and a first protective layer stacked on the transparent substrate layer;

[0009] The raw materials for preparing the transparent substrate layer include base material, ultraviolet absorber and antioxidant;

[0010] The raw material for preparing the first protective layer is selected from at least one of multifunctional acrylic resin, epoxy-modified acrylic resin, polyurethane-modified acrylic resin, fluoropolyether-modified acrylic resin, polysiloxane resin, epoxy resin, and polyurethane resin.

[0011] The composite material provided by the embodiments of the present disclosure includes a transparent substrate layer and a first protective layer. By making the raw materials for preparing the transparent substrate layer include an ultraviolet absorber and an antioxidant, the ultraviolet absorber can absorb ultraviolet rays, reduce the damage caused by UV light to the transparent substrate layer, improve its weather resistance and aging resistance, and thus delay its yellowing. The antioxidant and the ultraviolet absorber work synergistically to achieve a good synergistic anti-aging effect, further improving the UV yellowing resistance of the transparent substrate layer itself. By providing a first protective layer on the transparent substrate layer, the raw materials for preparing the first protective layer are selected from at least one of a multifunctional acrylic resin, an epoxy-modified acrylic resin, a polyurethane-modified acrylic resin, a fluoropolyether-modified acrylic resin, a polysiloxane resin, an epoxy resin, and a polyurethane resin. Such resin layers have good density and hardness, which can prevent yellowing caused by the penetration of sweat and dirt such as cosmetics into the transparent substrate layer, while also improving its wear resistance, thereby increasing its yellowing resistance life. It can be seen that the composite material provided by the embodiments of the present disclosure not only has excellent anti-ultraviolet yellowing performance, but also has excellent anti-dirt yellowing performance.

[0012] In some possible implementations, the curing degree of the first protective layer is greater than or equal to 85%, thereby ensuring high density of the first protective layer and effectively preventing dirt such as chemicals and moisture from penetrating into the transparent substrate layer.

[0013] In some possible implementations, the composite material further includes: a second protective layer, and the second protective layer is selected from one of a reflection-enhancing layer and a dirt-resistant layer.

[0014] In some possible implementations, the composite material further includes: a third protective layer, and the third protective layer is selected from the other of the reflection-enhancing layer and the anti-fouling layer.

[0015] The reflective enhancement layer can further improve the surface hardness of the composite material, and at the same time can reflect UV light, further preventing UV light from entering the transparent substrate layer, and effectively improving the UV yellowing resistance of the composite material.

[0016] The anti-fouling layer can improve the surface hydrophobicity and oleophobicity of the composite material and reduce the residue of dirt on its surface. This can effectively prevent dirt such as chemicals and water from invading the transparent substrate layer, and further avoid yellowing of the transparent substrate layer caused by the intrusion of dirt such as chemicals and water.

[0017] In some possible implementations, the raw materials for preparing the reflection-enhancing layer include at least one of titanium oxide, zirconium oxide, tin oxide, zinc oxide, silicon oxide, niobium oxide, aluminum oxide, chromium oxide, magnesium oxide, germanium oxide, gallium oxide, antimony oxide, and platinum oxide.

[0018] In some possible implementations, the raw material for preparing the anti-fouling layer is at least one of a fluorine-containing multifunctional acrylic resin, a fluorine-containing epoxy-modified acrylic resin, a fluorine-containing polyurethane-modified acrylic resin, a fluorine-containing fluoropolyether-modified acrylic resin, a fluorine-containing polysiloxane resin, a fluorine-containing epoxy resin, and a fluorine-containing polyurethane resin.

[0019] In some possible implementations, the anti-fouling layer is an anti-fingerprint coating.

[0020] The anti-fingerprint coating has good hydrophobicity and oleophobicity, which can make the composite material have an excellent smooth feel and is not easy to produce fingerprints.

[0021] In some possible implementations, the base material satisfies at least one of the following conditions: transmittance ≥ 50%, haze ≤ 20%, hardness ≥ Shore hardness 60A, tensile strength ≥ 30 MPa, and elongation at break ≥ 50%.

[0022] By limiting the physical properties of the base material as described above, it is ensured that the transparent substrate has good transparency, impact resistance and touch feel, thereby meeting the needs of protective cases for hand-touch devices such as mobile phones.

[0023] In some possible implementations, the matrix material is selected from at least one of TPU, TPE, TPEE, PC, PMMA, TPO, and transparent nylon.

[0024] In some possible implementations, in the raw materials for preparing the transparent substrate layer, the mass percentage of the base material is 94%-97%, the mass percentage of the ultraviolet absorber is 2%-5%, and the mass percentage of the antioxidant is 0.1%-1.5%.

[0025] In some possible implementations, the composite material is in the form of a plate.

[0026] In some possible implementations, the composite material has a structural form of a shell.

[0027] In some possible implementations, the housing is a protective shell of a handheld device, and the handheld device includes a mobile phone, a tablet computer, a camera, or a remote control, for example, a mobile phone protective shell.

[0028] In another aspect, a method for preparing a composite material is provided, wherein the composite material is as described above;

[0029] The preparation method of the composite material comprises: preparing a transparent substrate layer;

[0030] A first protective layer is prepared on at least one surface of the transparent substrate layer.

[0031] In some possible implementations, the method for preparing the composite material further includes: preparing a second protective layer on a surface of the first protective layer away from the transparent substrate layer.

[0032] In some possible implementations, the method for preparing the composite material further includes: preparing a third protective layer on a surface of the second protective layer away from the first protective layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG1 is a schematic structural diagram of a first exemplary composite material provided by an embodiment of the present disclosure;

[0034] FIG2 is a schematic structural diagram of a second exemplary composite material provided in an embodiment of the present disclosure;

[0035] FIG3 is a schematic structural diagram of a third exemplary composite material provided in an embodiment of the present disclosure;

[0036] FIG4 is a schematic structural diagram of a fourth exemplary composite material provided by an embodiment of the present disclosure;

[0037] FIG5 is a schematic structural diagram of a fifth exemplary composite material provided by an embodiment of the present disclosure.

[0038] The reference numerals represent:

[0039] 100. Transparent substrate layer;

[0040] 200, first protective layer;

[0041] 300, second protective layer;

[0042] 400, the third protective layer;

[0043] 001, reflective layer;

[0044] 002. Dirt-resistant layer. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present disclosure in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0046] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0047] In the description of the present disclosure, it should be understood that the terms "upper" and "lower" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are intended only to facilitate the description of the present disclosure and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific position, be constructed and operate in a specific position, and therefore should not be understood as a limitation on the present disclosure. For example, these positional nouns are generally based on the relative positions shown in Figures 1-5, and are used only to more clearly describe the relationship between structures, not to describe absolute positions. When the product is placed in different postures, the position may change, for example, "upper" and "lower" may be interchangeable.

[0048] In the related art, transparent protective cases made of TPU material are susceptible to irreversible yellowing after a period of use due to the influence of ultraviolet (UV) rays, thus affecting the user experience. Therefore, it is very necessary to improve the yellowing resistance of transparent protective cases.

[0049] The present disclosure provides a composite material comprising: a transparent substrate layer; and a first protective layer laminated on the transparent substrate layer. The transparent substrate layer is prepared from raw materials including a base material, a UV absorber, and an antioxidant; the first protective layer is prepared from raw materials selected from at least one of a multifunctional acrylic resin, an epoxy-modified acrylic resin, a polyurethane-modified acrylic resin, a fluoropolyether-modified acrylic resin, a polysiloxane resin, an epoxy resin, and a polyurethane resin.

[0050] The composite material provided by the embodiments of the present disclosure includes a transparent substrate layer and a first protective layer. By making the raw materials for preparing the transparent substrate layer include an ultraviolet absorber and an antioxidant, the ultraviolet absorber can absorb ultraviolet rays, reduce the damage caused by UV light to the transparent substrate layer, improve its weather resistance and aging resistance, and thus delay its yellowing. The antioxidant and the ultraviolet absorber work synergistically to achieve a good synergistic anti-aging effect, further improving the UV yellowing resistance of the transparent substrate layer itself. By providing a first protective layer on the transparent substrate layer, the raw materials for preparing the first protective layer are selected from at least one of a multifunctional acrylic resin, an epoxy-modified acrylic resin, a polyurethane-modified acrylic resin, a fluoropolyether-modified acrylic resin, a polysiloxane resin, an epoxy resin, and a polyurethane resin. Such resin layers have good density and hardness, which can prevent yellowing caused by the penetration of sweat and dirt such as cosmetics into the transparent substrate layer, while also improving its wear resistance, thereby increasing its yellowing resistance life. It can be seen that the composite material provided by the embodiments of the present disclosure not only has excellent anti-ultraviolet yellowing performance, but also has excellent anti-dirt yellowing performance.

[0051] Studies have found that users' hands often have residues of cosmetics, hand creams and other chemicals. When the chemicals remaining on the hands of users penetrate into materials such as TPU together with hand sweat, the chemical compounds contained in the chemical, such as tocopherol acetate, are easily hydrolyzed into tocopherol. Tocopherol is oxidized into tocopherolquinone under the promotion of hand sweat and light. Tocopherol is yellowish-brown in color, which causes yellowing of the material due to the infiltration of dirt. The disclosed embodiment further adds a first protective layer on the transparent substrate layer, utilizing its good density and hardness characteristics to effectively prevent chemicals and hand sweat from invading the interior of the transparent substrate layer, thereby improving its anti-dirt and yellowing effect.

[0052] For the transparent substrate layer, the base material used therein satisfies at least one of the following conditions: transmittance ≥ 50%, haze ≤ 20%, hardness ≥ Shore hardness 60A, tensile strength ≥ 30 MPa, and elongation at break ≥ 50%.

[0053] In some examples, the base material can be configured to have a transmittance of at least 50% and a haze of ≤20%. Furthermore, the base material can be configured to have at least one of the following conditions: hardness ≥ Shore A 60A, tensile strength ≥30 MPa, and elongation at break ≥50%. For example, the base material can be configured to simultaneously meet all of the above conditions.

[0054] By limiting the physical properties of the base material as described above, it is ensured that the transparent substrate has good transparency, impact resistance and touch feel, thereby meeting the needs of protective cases for hand-touch devices such as mobile phones.

[0055] Exemplarily, the matrix material satisfying at least one of the above conditions can be selected from at least one of TPU (Thermoplastic Urethane), TPE (Thermoplastic Elastomer), TPEE (Thermoplastic Polyester Elastomer), PC (Polycarbonate), PMMA (Polymethyl Methacrylate), TPO (Thermoplastic polyolefin), and transparent nylon.

[0056] In the embodiments of the present disclosure, ultraviolet absorbers that can be applied to the above-mentioned base material and achieve good ultraviolet absorption effect include but are not limited to: salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, substituted acrylonitrile ultraviolet absorbers, triazine ultraviolet absorbers and hindered amine ultraviolet absorbers.

[0057] For example, the ultraviolet absorbers involved in the embodiments of the present disclosure include but are not limited to the following: ultraviolet absorber UV-0 (2,4-dihydroxybenzophenone), ultraviolet absorber UV-1 (N-(ethoxycarbonylphenyl)-N'-methyl-N'-phenylformamidine), ultraviolet absorber UV-9 (4-methoxy-2-hydroxybenzophenone), ultraviolet absorber UV-234 (2-(2H-benzotriazole-2)-4,6-bis(1-methyl-1-phenylethyl)phenol), ultraviolet absorber UV-326 (2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole), ultraviolet absorber UV-327 (2-(2'-hydroxy-3',5'-di-tert-butylbenzene UV absorber UV-328 (2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole), UV absorber UV-329 (2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole), UV absorber UV-360 (2,2'-methylenebis(4-tert-octyl-6-benzotriazolephenol)), UV absorber UV-531 (2-hydroxy-4-n-octyloxybenzophenone), UV absorber UV-1164 (2-(4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl)-5-octyloxyphenol), UV absorber UV-1577 (2-(4,6-diphenyl-1,3,5- triazine-2-yl)-5-hexyloxy-phenol), ultraviolet absorber UV-P (2-(2'-hydroxy-5'-methylphenyl)benzotriazole).

[0058] In the embodiment of the present disclosure, the antioxidant that can be applied to the above-mentioned base material and can act synergistically with the ultraviolet absorber can be a hindered phenol antioxidant, a thioester antioxidant, etc. Some exemplary antioxidants include but are not limited to: antioxidant 1010, antioxidant 1076, antioxidant 168, antioxidant 245, antioxidant 1790, antioxidant 330, antioxidant DSTP, antioxidant DSTDP, etc.

[0059] In some examples, based on 100% by mass of the raw materials for preparing the transparent substrate layer, the mass percentage of the base material is 94%-97%, the mass percentage of the ultraviolet absorber is 2%-5%, and the mass percentage of the antioxidant is 0.1%-1.5%.

[0060] Illustratively, the mass percentage of the matrix material includes but is not limited to 94%, 94.5%, 95%, 95.5%, 96%, 96.5%, 97%, etc., the mass percentage of the ultraviolet absorber includes but is not limited to 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc., and the mass percentage of the antioxidant includes but is not limited to 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, etc.

[0061] The base material, ultraviolet absorber and antioxidant work synergistically in the above-mentioned ratio to ensure that the prepared transparent substrate layer has excellent transparency, mechanical properties and tactile properties, as well as excellent resistance to UV yellowing and dirt yellowing.

[0062] When used, the base material can be in the form of particles. For example, the particle size of the base material particles can be 1 mm to 10 mm, which is convenient for storage and melting processing.

[0063] In the embodiment of the present disclosure, the first protective layer is a dense resin layer whose curing degree is greater than or equal to 85%. For example, its curing degree can be further greater than or equal to 90%, and further can be greater than or equal to 95%. This can ensure that the first protective layer has high density and effectively prevents chemicals, moisture and other dirt from penetrating into the transparent substrate layer.

[0064] The raw material for preparing the first protective layer is selected from at least one of multifunctional acrylic resin, epoxy-modified acrylic resin, polyurethane-modified acrylic resin, fluoropolyether-modified acrylic resin, polysiloxane resin, epoxy resin, and polyurethane resin.

[0065] The functionality of the multifunctional acrylic resin may be 2-12, further 2-6. Some suitable multifunctional acrylic resins include but are not limited to polyurethane acrylates, polyester acrylates, epoxy acrylates, and the like.

[0066] Taking multifunctional polyurethane acrylates as an example, this includes but is not limited to at least one of aromatic polyurethane hexaacrylate resin, aromatic polyurethane triacrylate resin, aromatic polyurethane diacrylate resin, aliphatic polyurethane methpentaacrylate resin, aliphatic polyurethane methhexaacrylate resin, aliphatic polyurethane methtetraacrylate resin, aliphatic polyurethane trimethacrylate resin, aliphatic polyurethane tetramethacrylate resin and aliphatic polyurethane pentamethacrylate resin.

[0067] In some implementations, the composite material provided by the embodiments of the present disclosure further includes: a second protective layer, wherein the second protective layer is selected from one of a reflection-enhancing layer and a dirt-resistant layer.

[0068] The reflective enhancement layer can further improve the surface hardness of the composite material, and at the same time can reflect UV light, further preventing UV light from entering the transparent substrate layer, and effectively improving the UV yellowing resistance of the composite material.

[0069] The anti-fouling layer can improve the surface hydrophobicity and oleophobicity of the composite material and reduce the residue of dirt on its surface. This can effectively prevent dirt such as chemicals and water from invading the transparent substrate layer, and further avoid yellowing of the transparent substrate layer caused by the intrusion of dirt such as chemicals and water.

[0070] In some implementations, the composite material provided by the embodiments of the present disclosure further includes: a third protective layer, which is different from the second protective layer and is selected from another one of a reflective enhancement layer and a dirt resistance layer.

[0071] By further arranging the third protective layer, it is further ensured that the transparent substrate layer can not only effectively prevent the transparent substrate layer from yellowing due to UV light, but also effectively prevent the transparent substrate layer from yellowing due to the intrusion of dirt such as chemicals and moisture.

[0072] In some examples, as shown in FIG1 , the composite material provided by the embodiments of the present disclosure includes: a transparent substrate layer 100 and a first protective layer 200, wherein the first protective layer 200 is laminated on at least one surface of the transparent substrate layer 100. For example, the first protective layer 200 is laminated on the upper surface of the transparent substrate layer 100 as shown in FIG1 . Of course, the first protective layer 200 can also be further laminated on the lower surface of the transparent substrate layer 100.

[0073] In some examples, as shown in FIG2 , the composite material provided by the embodiments of the present disclosure includes: a transparent substrate layer 100, a first protective layer 200, and a second protective layer 300. The first protective layer 200 is laminated and disposed on at least one surface of the transparent substrate layer 100, and the second protective layer 300 is laminated and disposed on a surface of the first protective layer 200 that is away from the transparent substrate layer 100. The second protective layer 300 is a reflection-enhancing layer 001.

[0074] In some examples, as shown in FIG3 , the composite material provided by the embodiments of the present disclosure includes: a transparent substrate layer 100, a first protective layer 200, and a second protective layer 300. The first protective layer 200 is laminated and disposed on at least one surface of the transparent substrate layer 100, and the second protective layer 300 is laminated and disposed on a surface of the first protective layer 200 that is away from the transparent substrate layer 100. The second protective layer 300 is an anti-fouling layer 002.

[0075] In some examples, as shown in FIG4 , the composite material provided by the embodiments of the present disclosure includes: a transparent substrate layer 100, a first protective layer 200, a second protective layer 300, and a third protective layer 400. The first protective layer 200 is laminated and disposed on at least one surface of the transparent substrate layer 100, the second protective layer 300 is laminated and disposed on a surface of the first protective layer 200 remote from the transparent substrate layer 100, and the third protective layer 400 is laminated and disposed on a surface of the second protective layer 300 remote from the first protective layer 200. The second protective layer 300 is a reflection-enhancing layer 001, and the third protective layer 400 is an anti-fouling layer 002.

[0076] In some examples, as shown in FIG5 , the composite material provided by the embodiments of the present disclosure includes: a transparent substrate layer 100, a first protective layer 200, a second protective layer 300, and a third protective layer 400. The first protective layer 200 is laminated and disposed on at least one surface of the transparent substrate layer 100, the second protective layer 300 is laminated and disposed on a surface of the first protective layer 200 remote from the transparent substrate layer 100, and the third protective layer 400 is laminated and disposed on a surface of the second protective layer 300 remote from the first protective layer 200. The second protective layer 300 is an anti-fouling layer 002, and the third protective layer 400 is a reflection-enhancing layer 001.

[0077] On the basis of ensuring the yellowing resistance of the composite material, the thickness of each layer can be determined according to the actual application scenario of the composite material.

[0078] Taking the composite material as the shell as an example, the thickness of the transparent substrate layer can be 0.3mm-2mm, the thickness of the first protective layer can be 1μm-30μm, the thickness of the reflection-enhancing layer can be 10nm-300nm, and the thickness of the anti-fouling layer can be 1μm-10μm.

[0079] The thickness of the transparent substrate layer includes but is not limited to 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, etc.

[0080] The thickness of the first protective layer includes but is not limited to 1μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, etc.

[0081] The thickness of the reflection-enhancing layer includes but is not limited to 50 nm, 70 nm, 100 nm, 120 nm, 150 nm, 170 nm, 200 nm, 230 nm, 250 nm, 280 nm, 300 nm, etc.

[0082] The thickness of the anti-fouling layer includes but is not limited to 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0083] In the embodiment of the present disclosure, the raw materials for preparing the reflection-enhancing layer include at least one of titanium oxide, zirconium oxide, tin oxide, zinc oxide, silicon oxide, niobium oxide, aluminum oxide, chromium oxide, magnesium oxide, germanium oxide, gallium oxide, antimony oxide, and platinum oxide.

[0084] The reflection-enhancing layer may be a single-layer structure, which is prepared by any of the above-mentioned metal oxides. The reflection-enhancing layer may also be a multi-layer structure, wherein the multiple layers are prepared by different metal oxides.

[0085] The anti-reflection layer prepared by using the metal oxide can achieve a reflectivity of ≥20% for UV light with a wavelength of 280nm-400nm and a reflectivity of ≤5% in the visible light region of 400nm-700nm.

[0086] In the disclosed embodiments, the anti-fouling layer is prepared from at least one of a fluorinated multifunctional acrylic resin, a fluorinated epoxy-modified acrylic resin, a fluorinated polyurethane-modified acrylic resin, a fluorinated fluoropolyether-modified acrylic resin, a fluorinated polysiloxane resin, a fluorinated epoxy resin, and a fluorinated polyurethane resin. Fluorine is added to these resins to enhance their hydrophobic and oleophobic properties.

[0087] For example, the anti-fouling layer of the disclosed embodiments is an anti-fingerprint coating (AFC). This coating has excellent hydrophobicity and oleophobicity, which gives the composite material an excellent smooth feel and resists fingerprints. All currently known anti-fingerprint coatings in the art are suitable for use in the disclosed embodiments.

[0088] In some examples, for the first protective layer, its modulus can be 1GPa-10GPa, including but not limited to 1GPa, 2GPa, 3GPa, 4GPa, 5GPa, 6GPa, 7GPa, 8GPa, 9GPa, 10GPa, etc., so that the first protective layer has the desired hardness.

[0089] In some examples, the modulus of the anti-fouling layer can be 1 GPa-10 GPa, including but not limited to 1 GPa, 2 GPa, 3 GPa, 4 GPa, 5 GPa, 6 GPa, 7 GPa, 8 GPa, 9 GPa, 10 GPa, etc., so that the anti-fouling layer has the desired hardness.

[0090] The anti-fouling layer has a water drop angle of ≥90° and an oil drop angle of ≥50°. For example, the water drop angle of the anti-fouling layer can be greater than or equal to 100°, 110°, 120°, 130°, etc., and the oil drop angle can be greater than or equal to 60°, 70°, 80°, 90°, etc. This configuration ensures that the anti-fouling layer has excellent hydrophobic and oleophobic properties, preventing dirt from adhering to its surface.

[0091] The composite material provided by the embodiments of the present disclosure can be designed into various structural forms so that it can be used in various application scenarios.

[0092] One example is that the structural form of the composite material is a plate. The composite material in plate form can be cut into various shapes or formed into various shapes through molds. It is suitable for existing in a flat state. For example, the plate can be used as a surface protection pad, such as for a desktop, etc.

[0093] Another example is that the structure of the composite material is in the form of a shell. For example, the shell can be a protective shell for a handheld device, where the handheld devices involved include but are not limited to mobile phones, tablet computers, cameras, remote controls, and the like.

[0094] In some embodiments, the embodiments of the present disclosure provide a mobile phone protective case, the material of which is the composite material involved in the embodiments of the present disclosure. In this way, even if the user's hands are sweaty or there are chemicals such as cosmetics and hand creams on their hands and they touch the mobile phone protective case for a long time, the mobile phone protective case will not turn yellow.

[0095] The sheet material or housing provided by the embodiments of the present disclosure possesses all the advantages mentioned above for the composite materials. Specifically, the sheet material or housing provided by the embodiments of the present disclosure exhibits at least excellent resistance to UV yellowing, resistance to yellowing from dirt, and impact resistance. Furthermore, the housing also exhibits excellent smoothness and anti-fingerprint properties.

[0096] In another aspect, embodiments of the present disclosure also provide a method for preparing a composite material, comprising: preparing a transparent substrate layer; and forming a first protective layer on at least one surface of the transparent substrate layer. Thus, a composite material comprising the transparent substrate layer and the first protective layer can be prepared.

[0097] Furthermore, the method for preparing the composite material provided in the embodiment of the present disclosure further includes: forming a second protective layer on a surface of the first protective layer away from the transparent substrate layer. Thus, a composite material including the transparent substrate layer, the first protective layer, and the second protective layer can be prepared.

[0098] Furthermore, the method for preparing the composite material provided in the embodiments of the present disclosure further includes forming a third protective layer on a surface of the second protective layer away from the first protective layer. Thus, a composite material comprising a transparent substrate layer, a first protective layer, a second protective layer, and a third protective layer can be prepared.

[0099] The preparation process for the transparent substrate layer can be adaptively designed based on the composite material's structural form. For example, for a composite material in the form of a sheet, the transparent substrate layer preparation method includes: utilizing the raw materials for the transparent substrate layer and applying a coating process to form the transparent substrate layer on a substrate. Applicable coating processes include, but are not limited to, spray coating, dip coating, blade coating, roller coating, ultrasonic spray coating, and slot coating.

[0100] For a composite material in the form of a shell, a method for preparing a transparent substrate layer includes: using raw materials for preparing the transparent substrate layer, and obtaining the transparent substrate layer through an injection molding process, a hot pressing process, or an extrusion molding process. When forming the transparent substrate layer through injection molding, a mold having a specific structural form is used to obtain the transparent substrate layer having the specific structural form.

[0101] The first protective layer can be prepared by coating the raw materials for preparing the first protective layer on the transparent substrate layer through a coating process. Suitable coating processes include, but are not limited to, spray coating, dip coating, blade coating, roller coating, ultrasonic spray coating, and slit coating.

[0102] The preparation processes for the second and third protective layers are as follows, based on their respective raw materials. When one of the second and third protective layers is a reflection-enhancing layer, the reflection-enhancing layer is prepared on the surface of the corresponding layer using the raw materials for the reflection-enhancing layer by a vapor deposition process.

[0103] When one of the second protective layer and the third protective layer is a stain-resistant layer, the stain-resistant layer is deposited on the surface of the corresponding layer using raw materials for the stain-resistant layer through a vapor deposition process or a coating process. Suitable coating processes include, but are not limited to, spray coating, dip coating, doctor blade coating, roller coating, ultrasonic spray coating, and slot coating.

[0104] The preferred embodiment of the present application will be described in more detail below. Although the preferred embodiment of the present application is described below, it should be understood that the present application can be realized in various forms and should not be limited by the embodiment set forth herein. In the embodiment, if no specific technology or conditions are indicated, the technology or conditions described in the document in this area or the product instructions are used. If the reagents used or the instrument are not indicated by the manufacturer, they are all conventional products that can be obtained commercially.

[0105] Example 1

[0106] This embodiment 1 provides a composite material, see Figure 2, the composite material includes a transparent substrate layer 100 with a thickness of 2 mm, a first protective layer 200 with a thickness of 20 μm, and a second protective layer 300 with a thickness of 200 nm. The first protective layer 200 is stacked on the upper surface of the transparent substrate layer 100, and the second protective layer 300 is a reflection-enhancing layer 001, which is stacked on the upper surface of the first protective layer 200.

[0107] The transparent substrate layer 100 is prepared from the following raw materials: 96% by mass of aliphatic TPU, 3% by mass of ultraviolet absorber 326, and 1% by mass of antioxidant 245. The aliphatic TPU is prepared using hexamethylene diisocyanate (HDI) as a monomer.

[0108] The first protective layer is made of epoxy-modified acrylic resin, and the second protective layer 300 is an anti-fingerprint coating, which is prepared using Shin-Etsu fluorine antifouling coating.

[0109] The composite material provided in Example 1 was tested for resistance to UV yellowing. Using a UVA bulb, the composite material was exposed to ultraviolet light at 50°C for 4 hours and then condensed at 60°C for 4 hours for 100 hours. No yellowing of the composite material was detected. The composite material provided in Example 1 was also tested for resistance to dirt and yellowing. The composite material was coated on its surface with a mixture of cosmetics containing tocopheryl acetate and water (at a mass ratio of 1:1) and stored in a sealed environment. After 100 hours, no yellowing of the composite material was detected.

[0110] It can be seen that the composite material provided in Example 1, by using aliphatic TPU as the matrix material, does not have a benzene ring therein, and UV irradiation will not cause irreversible yellowing due to the formation of quinone imine. By adding an ultraviolet absorber 326 and an antioxidant 245 to the transparent substrate layer 100, the two work synergistically to absorb UV light incident on the interior of the transparent substrate, further effectively improving its resistance to UV yellowing. By providing a first protective layer 200, utilizing its good density, it is possible to effectively prevent dirt from entering the transparent substrate layer 100, reduce the penetration of dirt into the transparent substrate layer 100, and effectively improve its resistance to dirt and yellowing. By providing a second protective layer 300, the surface of the composite material is given excellent hydrophobic and oleophobic properties, effectively reducing the residue of dirt on the surface, and further improving the composite material's resistance to dirt and yellowing.

[0111] Example 2

[0112] This embodiment 2 provides a composite material, see Figure 3, the composite material includes a transparent substrate layer 100 with a thickness of 2 mm, a first protective layer 200 with a thickness of 20 μm, and a second protective layer 300 with a thickness of 6 μm. The first protective layer 200 is stacked on the upper surface of the transparent substrate layer 100, and the second protective layer 300 is a dirt-resistant layer 002, which is stacked on the upper surface of the first protective layer 200.

[0113] The transparent substrate layer 100 is made of the same raw materials as in Example 1 and will not be described in detail herein. The first protective layer is made of polyurethane modified acrylic resin, and the second protective layer 300 is the anti-reflection layer 001, which is made of zirconium dioxide.

[0114] The composite material provided in Example 2 was subjected to an anti-UV yellowing test and an anti-dirt yellowing test using the same yellowing test method as in Example 1, and no yellowing phenomenon was detected in the composite material.

[0115] The composite material provided in Example 2 effectively enhances its resistance to UV yellowing by adding an ultraviolet absorber 326 and an antioxidant 245 to the transparent substrate layer 100. The first protective layer 200, with its excellent density, effectively prevents dirt from entering the transparent substrate layer 100, reducing dirt's ability to penetrate the transparent substrate layer 100 and effectively improving its resistance to yellowing. The second protective layer 300, while ensuring high light transmittance, reflects a greater amount of UV light, further enhancing the composite material's resistance to UV yellowing.

[0116] Example 3

[0117] This embodiment 3 provides a composite material, see Figure 4, the composite material includes a transparent substrate layer 100 with a thickness of 2 mm, a first protective layer 200 with a thickness of 20 μm, a second protective layer 300 with a thickness of 200 nm, and a third protective layer 400 with a thickness of 5 μm. The first protective layer 200 is stacked on the upper surface of the transparent substrate layer 100, the second protective layer 300 is a reflection-enhancing layer 001, which is stacked on the upper surface of the first protective layer 200, and the third protective layer 400 is an anti-fouling layer 002, which is stacked on the upper surface of the second protective layer 300.

[0118] The transparent substrate layer 100 is made from the same raw materials as in Example 1 and will not be further described here. The first protective layer 200 is made of aliphatic polyurethane methyl hexaacrylate resin, the second protective layer 300 is made of zirconium dioxide, and the third protective layer 400 is an anti-fingerprint coating made from Shin-Etsu fluorine-based antifouling coating.

[0119] The composite material provided in Example 3 was subjected to an anti-UV yellowing test and an anti-dirt yellowing test using the same yellowing test method as in Example 1, and no yellowing phenomenon was detected in the composite material.

[0120] The composite material provided in Example 3 effectively improves its resistance to UV yellowing by adding an ultraviolet absorber 326 and an antioxidant 245 to the transparent substrate layer 100. By providing a first protective layer 200 and utilizing its good density, it can effectively prevent dirt from entering the transparent substrate layer 100, reduce the penetration of dirt into the transparent substrate layer 100, and effectively improve its resistance to dirt and yellowing. By providing a second protective layer 300, while ensuring that the composite material has a high light transmittance, more UV light is reflected, further improving the composite material's resistance to UV yellowing. By providing a third protective layer 400, the composite material surface is given excellent hydrophobic and oleophobic properties, effectively reducing the residue of dirt on the surface, and further improving the composite material's resistance to dirt and yellowing.

[0121] Example 4

[0122] This Example 4 provides a composite material, the structure of which is shown in Figure 4. The composite material of Example 4 is substantially the same as the composite material of Example 3, except that the aliphatic TPU in the transparent substrate is replaced with an aromatic TPU. The aromatic TPU is prepared using diphenylmethane diisocyanate (MDI) as a monomer.

[0123] The composite material provided in Example 4 was subjected to UV yellowing resistance test and dirt yellowing resistance test using the same yellowing test method as in Example 1. No yellowing phenomenon was detected in the composite material. It can be seen that the composite material can also achieve excellent UV yellowing resistance and dirt yellowing resistance effects.

[0124] Example 5

[0125] This embodiment 5 provides a composite material, the structure of which is shown in FIG4 . The composite material described in embodiment 5 is substantially the same as the composite material described in embodiment 3, except that the aliphatic TPU in the transparent substrate is replaced with TPEE.

[0126] The composite material provided in Example 4 was subjected to anti-UV yellowing test and anti-fouling yellowing test using the same yellowing test method as in Example 1. No yellowing was detected in the composite material. This shows that the composite material can also achieve excellent anti-UV yellowing and anti-fouling yellowing effects, and in particular, its anti-fouling yellowing effect is even better.

[0127] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solutions of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the scope of protection of the present disclosure.

Claims

1. A composite material, wherein: The composite material comprises: a transparent substrate layer and a first protective layer stacked on the transparent substrate layer; The raw materials for preparing the transparent substrate layer include a base material, an ultraviolet absorber and an antioxidant; The raw material for preparing the first protective layer is selected from at least one of multifunctional acrylic resin, epoxy-modified acrylic resin, polyurethane-modified acrylic resin, fluoropolyether-modified acrylic resin, polysiloxane resin, epoxy resin, and polyurethane resin.

2. The composite material according to claim 1, wherein The curing degree of the first protective layer is greater than or equal to 85%.

3. The composite material according to claim 1, wherein The composite material further comprises: a second protective layer, which is selected from a reflection enhancement layer and a dirt resistance layer.

4. The composite material according to claim 3, wherein: The composite material further includes: a third protective layer, and the third protective layer is selected from the other of the reflection enhancement layer and the dirt resistance layer.

5. The composite material according to claim 3, wherein The raw material for preparing the reflection enhancement layer includes at least one of titanium oxide, zirconium oxide, tin oxide, zinc oxide, silicon oxide, niobium oxide, aluminum oxide, chromium oxide, magnesium oxide, germanium oxide, gallium oxide, antimony oxide and platinum oxide.

6. The composite material according to claim 3, wherein: The raw material for preparing the anti-fouling layer is at least one of fluorine-containing multifunctional acrylic resin, fluorine-containing epoxy-modified acrylic resin, fluorine-containing polyurethane-modified acrylic resin, fluorine-containing fluoropolyether-modified acrylic resin, fluorine-containing polysiloxane resin, fluorine-containing epoxy resin, and fluorine-containing polyurethane resin.

7. The composite material according to claim 3, wherein The anti-fouling layer is an anti-fingerprint coating.

8. The composite material according to any one of claims 1 to 7, wherein: The base material meets at least one of the following conditions: light transmittance ≥ 50%, haze ≤ 20%, hardness ≥ Shore hardness 60A, tensile strength ≥ 30 MPa, and elongation at break ≥ 50%.

9. The composite material according to any one of claims 1 to 7, wherein: The matrix material is selected from at least one of TPU, TPE, TPEE, PC, PMMA, TPO and transparent nylon.

10. The composite material according to any one of claims 1 to 9, wherein: In the raw materials for preparing the transparent substrate layer, the mass percentage of the base material is 94%-97%, the mass percentage of the ultraviolet absorber is 2%-5%, and the mass percentage of the antioxidant is 0.1%-1.5%.

11. The composite material according to any one of claims 1 to 10, wherein: The composite material is in the form of a plate.

12. The composite material according to any one of claims 1 to 10, wherein: The composite material has a structural form of a shell.

13. The composite material according to claim 12, wherein: The housing is a protective shell of a handheld device, and the handheld device includes a mobile phone, a tablet computer, a camera or a remote controller.

14. A method for preparing a composite material, wherein: The composite material is as described in any one of claims 1 to 13; The method for preparing the composite material comprises: preparing a transparent substrate layer; A first protective layer is prepared on at least one surface of the transparent substrate layer.

15. The method for preparing a composite material according to claim 14, wherein: The method for preparing the composite material further includes: preparing a second protective layer on a surface of the first protective layer away from the transparent substrate layer.

16. The method for preparing a composite material according to claim 15, wherein: The method for preparing the composite material further includes: preparing a third protective layer on a surface of the second protective layer away from the first protective layer.

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