Curing-free extinction protective composite material and preparation method therefor

Abstract

Disclosed in the present invention are a curing-free extinction protective composite material and a preparation method therefor. The composite material comprises the following components: ETFE powder, 75-85 parts by mass of ETFE particles, 5.5-12 parts by mass of a blocking agent, 0 or 0.04-0.08 parts by mass of a brightening agent, 0 or 0.01-0.03 parts by mass of a whitening agent, 0.2-0.3 parts by mass of silicon dioxide, 0.2-0.3 parts by mass of a coupling agent, 0.1-0.3 parts by mass of a dispersing agent and 0.05-0.2 parts by mass of an antioxidant, wherein the sum of the ETFE powder and ETFE particles is 100 parts by mass, and the melt index of the ETFE powder is 18-22 g / min. Moreover, the preparation method is simple and easy in terms of operation; the film prepared from the composite material of the present invention has excellent mechanical properties and good high temperature resistance and aging resistance, has an L value of not less than 94 and has a good identification effect; additionally, the film prepared from the composite material of the present invention requires no curing, has good hydrophobicity, offers a self-cleaning effect, and has low maintenance and construction costs and is convenient in terms of replacement, making it suitable for use in the field of communication base stations.

Description

A curing-free matte protective composite material and its preparation method Technical Field

[0001] This invention relates to the field of engineering materials technology, and in particular to a curing-free matte protective composite material and its preparation method. Background Technology

[0002] In the field of communication base station applications, coatings are usually applied to the outer surfaces of signal devices, poles, towers, and transmitting and receiving equipment to provide a certain degree of protection and identification. These coatings are generally organic or inorganic modified coatings, which have poor resistance to long-term aging, are prone to discoloration and peeling, and have high secondary maintenance costs. This is especially true in some demanding fields, such as the reception of highly reflective light signals, where the impact is significant. At the same time, the coatings also have poor high-temperature resistance. Furthermore, the coating application process requires strict temperature and humidity control, making the operation inconvenient. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a curing-free matte protective composite material and its preparation method, which can replace the coating to play a protective and marking role, does not require curing, has a high light blocking rate, excellent mechanical properties, high temperature resistance and aging resistance, and achieves a high whiteness value with less inorganic filler.

[0004] To address the aforementioned technical problems, a first aspect of the present invention is to provide a curing-free matte protective composite material, comprising the following components in parts by weight:

[0005] 15-25 parts by weight of ETFE powder;

[0006] 75-85 parts by weight of ETFE granules;

[0007] 5.5-12 parts by weight of barrier agent;

[0008] Brightening agent is either absent or 0.04-0.08 parts by weight;

[0009] Whitening agent is either not added or 0.01-0.03 parts by weight;

[0010] 0.2-0.3 parts by weight of silicon dioxide;

[0011] 0.2-0.3 parts by weight of coupling agent;

[0012] Dispersant 0.1-0.3 parts by weight;

[0013] Antioxidant 0.05-0.2 parts by weight;

[0014] The mixture consists of 100 parts by weight of ETFE powder and ETFE granules, with the ETFE powder having a melt flow index of 18-22 g / min.

[0015] In this invention, ETFE (ethylene tetrafluoroethylene copolymer) is used as the resin matrix, giving the composite material excellent mechanical properties, as well as good high-temperature resistance and aging resistance, ensuring that the composite material plays a good protective role when applied in the field of communication base stations. The barrier agent mainly plays a role in blocking light, whitening and reflecting light, ensuring that the composite material plays a good marking role when applied in the field of communication base stations. The addition of brightening agent and whitening agent helps to further improve the whitening effect of the composite material. In the composite material provided by this invention, the amount of inorganic filler added is small, but when the composite material is used as a film, its L value is not less than 94, which has a good marking effect. At the same time, it does not require curing, has good hydrophobicity, has a self-cleaning effect, low maintenance cost, is easy to replace, and has low construction cost.

[0016] In one specific scheme, the coupling agent is a fluorinated silane coupling agent (heptadecyltrimethoxysilane).

[0017] The antioxidant is one or more of antioxidant S80, antioxidant 608, or antioxidant 168;

[0018] The dispersant is one or more of PE wax, EBS, and polyester wax.

[0019] The barrier agent is titanium dioxide.

[0020] In this specific embodiment of the invention, the barrier agent is titanium dioxide, which has a good whitening effect, especially when it works synergistically with brightener and whitening agent. However, the amount of titanium dioxide, brightener and whitening agent added cannot be too large or too small. If the amount added is too small (e.g., less than or equal to 5), the whitening effect is not obvious and cannot meet the requirement of L value greater than 94. If the amount of barrier agent added is in the range of 5.5-12, the surface of the film made of composite material will gradually become rough and the particle feel will gradually become obvious. If the amount is increased further, after exceeding 12, the film-forming properties of composite material are poor, or even unable to form a film.

[0021] In one specific embodiment, when the composite material is a 60 μm thick film, it has the following properties:

[0022] L value is greater than 94;

[0023] Tensile strength greater than 35 MPa;

[0024] Elongation at break greater than 300%;

[0025] Light transmittance is less than 10%.

[0026] To address the aforementioned technical problems, a second aspect of the present invention provides a method for preparing the aforementioned curing-free matte protective composite material, characterized by comprising the following steps:

[0027] S1. Preparation of bulk agglomerates: After the ETFE powder, barrier agent, silica and dispersant are mixed and dispersed evenly, they are preheated and melted in an internal mixer to obtain bulk agglomerates;

[0028] S2. Masterbatch preparation: The agglomerated bulk material obtained in step S1 is pressed to obtain uniformly shaped granules, i.e., masterbatch;

[0029] S3. Preparation of primary modified particles: Coupling agent and antioxidant are coated on the surface of the masterbatch obtained in step S2 to obtain modified masterbatch;

[0030] S4. Preparation of secondary modified particles: The primary modified particles and ETFE particles from step S3 are modified and granulated by a twin-screw granulation extruder to obtain secondary modified particles.

[0031] S5. Preparation of curing-free matte protective composite material: The secondary modified particles obtained in step S4 are passed through a twin-screw extruder again to obtain curing-free matte protective composite material particles.

[0032] In this invention, step S1 mainly uses ETFE powder to coat inorganic fillers, such as barrier agents. These fillers have very low content, and direct blending with the resin can lead to uneven dispersion and difficulty in controlling the metering accuracy. Using ETFE powder with a melt flow index preferably of 18-22 g / min allows for the initial coating of the inorganic filler powder, ensuring uniform dispersion and facilitating metering. Step S3 primarily involves thoroughly mixing the masterbatch with the coupling agent and antioxidant, ensuring uniform dispersion of the coupling agent and antioxidant. This results in stable composite material particles during granulation. Furthermore, it should be noted that the two granulation processes further improve the dispersion uniformity of the components in the composite material, preventing the appearance of particles or agglomerates on the film surface during later film-making processes, which could affect product quality. The material exhibits superior performance after two granulation processes.

[0033] In one specific scheme, the preheating melting temperature in step S1 is 200-230℃, and the time is 15-20min;

[0034] In step S2, a pressing machine is used for pressing;

[0035] The initial preparation of modified particles in step S3 is carried out in a high-speed mixer;

[0036] The temperature for both twin-screw granulation processes in steps S4 and S5 is 225-285℃.

[0037] In one specific embodiment, in step S1, the ETFE powder is 15-25 parts by weight, the barrier agent is 5.5-12 parts by weight, the dispersant is 0.1-0.3 parts by weight, and the silica is 0.2-0.3 parts by weight.

[0038] In step S3, the coupling agent is 0.2-0.3 parts by weight, and the antioxidant is 0.05-0.2 parts by weight;

[0039] In step S4, the ETFE granules are 75-85 parts by weight;

[0040] The total weight of ETFE powder and ETFE granules is 100 parts, and the melt index of ETFE powder is 18-22 g / min.

[0041] In one specific embodiment, the coupling agent is a fluorinated silane coupling agent;

[0042] The antioxidant is one or more of antioxidant S80, antioxidant 608, or antioxidant 168;

[0043] The dispersant is one or more of PE wax, EBS, and polyester wax;

[0044] The barrier agent is titanium dioxide.

[0045] The method for preparing the curable matting protective composite material provided by this invention involves sequentially preparing agglomerated bulk material, masterbatch, primary modified particles, secondary modified particles, and composite material particles. This ensures that the inorganic filler, which requires a small amount of additive, can be uniformly dispersed in the resin matrix. In particular, the barrier agent, silica, and dispersant are first coated with ETFE powder at a concentration of 18-22 g / min, which further promotes the uniform dispersion of the inorganic filler. The composite material preparation method of this invention is simple and easy to operate, and is readily applicable to the preparation of curable matting protective composite material particles. Detailed Implementation

[0046] The technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0047] The raw materials used in the embodiments of this invention are all commercially available, including:

[0048] ETFE powder (melt index 18-22 g / 10 min), ETFE granules (melt index 8-13 g / 10 min), titanium dioxide, zinc oxide, barium sulfate, silica, fluorinated silane coupling agent (heptadecyltrimethoxysilane), antioxidant S80, antioxidant 608, brightener, whitening agent and dispersant (PE wax).

[0049] The equipment used in the embodiments of this invention is all commercially available, including: high-speed mixer, internal mixer, press, high-speed mixer, and twin-screw granulation extruder.

[0050] Example 1: Preparation of Curing-Free Matte Protective Composite Material

[0051] S1. Preparation of bulk agglomerates: ETFE powder, barrier agent, silica and dispersant are stirred and dispersed in a high-speed mixer. The resulting blended powder is placed in an internal mixer and preheated and melted at 200-230℃ to obtain bulk agglomerates.

[0052] S2. Masterbatch preparation: The lumpy material obtained in step S1 is placed in a press and pressed into uniformly shaped granules, i.e., masterbatch;

[0053] S3. Preparation of primary modified particles: The masterbatch, fluorinated silane coupling agent, antioxidant S80, and antioxidant 608 are mixed in a high-speed mixer, and the temperature is controlled at 25-40℃. The surface of the masterbatch is modified to obtain primary modified particles coated with modifiers and antioxidants.

[0054] S4. Place the primary modified particles and ETFE particles from step S3 into a twin-screw extruder for granulation at a temperature of 225-285℃ to obtain secondary modified particles.

[0055] S5. Preparation of curing-free matte protective composite material: The secondary modified particles obtained in step S4 are placed in a twin-screw extruder for secondary granulation at a temperature of 225-285℃ to obtain curing-free matte protective composite material particles.

[0056] The addition ratio of each material in this embodiment is detailed in Table 1.

[0057] Example 2 and Comparative Examples 1-4

[0058] The composite material preparation processes of Examples 1-2 and Comparative Examples 1-4 are the same as those of Example 1, except that the types and amounts of materials added are different, as detailed in Table 1.

[0059] Table 1

[0060] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 ETFE Powder 202020202020 ETFE Particles 808080808080 Titanium Dioxide 127.55005 Zinc Oxide 000500 Barium Sulfate 000050 Silica 0.25 0.25 0.25 0.25 0.25 0.25 Fluorosilane Coupling Agent 0.25 0.25 0.25 0.25 0.25 0.25 Antioxidant s800 0.10.10.10.10.10.1 Antioxidant 6080 0.10.10.10.10.10.1 Brightening Agent 00.06 0000 0.06 Whitening Agent 00.02 0000 0.02 Dispersant 0.20.20.20.20.20.20.20.2

[0061] Test case

[0062] The testing method for this test case is as follows:

[0063] Tensile strength and elongation at break were tested according to the test method of GB / T 1040.3-2006. The standard for tensile strength is greater than 35 MPa, and the standard for elongation at break is greater than 300%.

[0064] Roughness was tested using a roughness tester, and the standard roughness range was 0.7-1.3.

[0065] The L-value test is conducted using a colorimeter, and the standard is an L-value greater than 94.

[0066] The appearance of the film is determined by visual inspection, and the standard is good film-forming properties, no pores, and no black spots;

[0067] Heat shrinkage was tested at 180℃ for 30 minutes, with a standard of less than 5%.

[0068] The water contact angle (on the bonding surface) is tested using a water contact angle tester, with a standard range of 50-75°.

[0069] Light transmittance was tested using a light transmittance meter, and the standard was that the light transmittance in the 350-2400nm wavelength range was less than 10%.

[0070] Gloss is tested using a gloss meter, with a standard range of 10°-20°.

[0071] In this test example, the standard selected is the requirement standard for thin films used in communication base stations.

[0072] Test sample preparation: The composite material particles obtained in Examples 1-2 and Comparative Examples 1-4 were extruded into 60μm films using a casting extruder. The extrusion temperature was 275-335℃, and the films were then cooled at 90-150℃ to obtain film samples.

[0073] The samples were tested, and the test results are shown in Table 2:

[0074] Table 2

[0075] Table 2 shows that when the barrier agent is zinc oxide and barium sulfate, the film-forming properties are poor, while when the additive is titanium dioxide, the film-forming properties are good. When the amount of titanium dioxide added is 5 parts by mass, even with the addition of brightener and whitening agent, the L value cannot meet the standard. Although further increasing the amount of brightener and whitening agent helps to increase the L value of the film, it has a significant impact on the film-forming properties. Therefore, the amount of brightener and whitening agent added should not be increased. However, when the amount of titanium dioxide added is increased to 7.5 parts by mass, not only is the film-forming property good, but all tests of the film meet the standard. When the amount of titanium dioxide is further increased to 12 parts by mass, even without the addition of brightener and whitening agent, the L value of the film can meet the standard requirements, but the film surface is rough and has a grainy feel.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. A curing-free matte protective composite material and its preparation method. Technical Field

[0077] This invention relates to the field of engineering materials technology, and in particular to a curing-free matte protective composite material and its preparation method. Background Technology

[0078] In the field of communication base station applications, coatings are usually applied to the outer surfaces of signal devices, poles, towers, and transmitting and receiving equipment to provide a certain degree of protection and identification. These coatings are generally organic or inorganic modified coatings, which have poor resistance to long-term aging, are prone to discoloration and peeling, and have high secondary maintenance costs. This is especially true in some demanding fields, such as the reception of highly reflective light signals, where the impact is significant. At the same time, the coatings also have poor high-temperature resistance. Furthermore, the coating application process requires strict temperature and humidity control, making the operation inconvenient. Summary of the Invention

[0079] The technical problem to be solved by the present invention is to provide a curing-free matte protective composite material and its preparation method, which can replace the coating to play a protective and marking role, does not require curing, has a high light blocking rate, excellent mechanical properties, high temperature resistance and aging resistance, and achieves a high whiteness value with less inorganic filler.

[0080] To address the aforementioned technical problems, a first aspect of the present invention is to provide a curing-free matte protective composite material, comprising the following components in parts by weight:

[0081] 15-25 parts by weight of ETFE powder;

[0082] 75-85 parts by weight of ETFE granules;

[0083] 5.5-12 parts by weight of barrier agent;

[0084] Brightening agent is either absent or 0.04-0.08 parts by weight;

[0085] Whitening agent is either not added or 0.01-0.03 parts by weight;

[0086] 0.2-0.3 parts by weight of silicon dioxide;

[0087] 0.2-0.3 parts by weight of coupling agent;

[0088] Dispersant 0.1-0.3 parts by weight;

[0089] Antioxidant 0.05-0.2 parts by weight;

[0090] The mixture consists of 100 parts by weight of ETFE powder and ETFE granules, with the ETFE powder having a melt flow index of 18-22 g / min.

[0091] In this invention, ETFE (ethylene tetrafluoroethylene copolymer) is used as the resin matrix, giving the composite material excellent mechanical properties, as well as good high-temperature resistance and aging resistance, ensuring that the composite material plays a good protective role when applied in the field of communication base stations. The barrier agent mainly plays a role in blocking light, whitening and reflecting light, ensuring that the composite material plays a good marking role when applied in the field of communication base stations. The addition of brightening agent and whitening agent helps to further improve the whitening effect of the composite material. In the composite material provided by this invention, the amount of inorganic filler added is small, but when the composite material is used as a film, its L value is not less than 94, which has a good marking effect. At the same time, it does not require curing, has good hydrophobicity, has a self-cleaning effect, low maintenance cost, is easy to replace, and has low construction cost.

[0092] In one specific scheme, the coupling agent is a fluorinated silane coupling agent (heptadecyltrimethoxysilane).

[0093] The antioxidant is one or more of antioxidant S80, antioxidant 608, or antioxidant 168;

[0094] The dispersant is one or more of PE wax, EBS, and polyester wax.

[0095] The barrier agent is titanium dioxide.

[0096] In this specific embodiment of the invention, the barrier agent is titanium dioxide, which has a good whitening effect, especially when it works synergistically with brightener and whitening agent. However, the amount of titanium dioxide, brightener and whitening agent added cannot be too large or too small. If the amount added is too small (e.g., less than or equal to 5), the whitening effect is not obvious and cannot meet the requirement of L value greater than 94. If the amount of barrier agent added is in the range of 5.5-12, the surface of the film made of composite material will gradually become rough and the particle feel will gradually become obvious. If the amount is increased further, after exceeding 12, the film-forming properties of composite material are poor, or even unable to form a film.

[0097] In one specific embodiment, when the composite material is a 60 μm thick film, it has the following properties:

[0098] L value is greater than 94;

[0099] Tensile strength greater than 35 MPa;

[0100] Elongation at break greater than 300%;

[0101] Light transmittance is less than 10%.

[0102] To address the aforementioned technical problems, a second aspect of the present invention provides a method for preparing the aforementioned curing-free matte protective composite material, characterized by comprising the following steps:

[0103] S1. Preparation of bulk agglomerates: After the ETFE powder, barrier agent, silica and dispersant are mixed and dispersed evenly, they are preheated and melted in an internal mixer to obtain bulk agglomerates;

[0104] S2. Masterbatch preparation: The agglomerated bulk material obtained in step S1 is pressed to obtain uniformly shaped granules, i.e., masterbatch;

[0105] S3. Preparation of primary modified particles: Coupling agent and antioxidant are coated on the surface of the masterbatch obtained in step S2 to obtain modified masterbatch;

[0106] S4. Preparation of secondary modified particles: The primary modified particles and ETFE particles from step S3 are modified and granulated by a twin-screw granulation extruder to obtain secondary modified particles.

[0107] S5. Preparation of curing-free matte protective composite material: The secondary modified particles obtained in step S4 are passed through a twin-screw extruder again to obtain curing-free matte protective composite material particles.

[0108] In this invention, step S1 mainly uses ETFE powder to coat inorganic fillers, such as barrier agents. These fillers have very low content, and direct blending with the resin can lead to uneven dispersion and difficulty in controlling the metering accuracy. Using ETFE powder with a melt flow index preferably of 18-22 g / min allows for the initial coating of the inorganic filler powder, ensuring uniform dispersion and facilitating metering. Step S3 primarily involves thoroughly mixing the masterbatch with the coupling agent and antioxidant, ensuring uniform dispersion of the coupling agent and antioxidant. This results in stable composite material particles during granulation. Furthermore, it should be noted that the two granulation processes further improve the dispersion uniformity of the components in the composite material, preventing the appearance of particles or agglomerates on the film surface during later film-making processes, which could affect product quality. The material exhibits superior performance after two granulation processes.

[0109] In one specific scheme, the preheating melting temperature in step S1 is 200-230℃, and the time is 15-20min;

[0110] In step S2, a pressing machine is used for pressing;

[0111] The initial preparation of modified particles in step S3 is carried out in a high-speed mixer;

[0112] The temperature for both twin-screw granulation processes in steps S4 and S5 is 225-285℃.

[0113] In one specific embodiment, in step S1, the ETFE powder is 15-25 parts by weight, the barrier agent is 5.5-12 parts by weight, the dispersant is 0.1-0.3 parts by weight, and the silica is 0.2-0.3 parts by weight.

[0114] In step S3, the coupling agent is 0.2-0.3 parts by weight, and the antioxidant is 0.05-0.2 parts by weight;

[0115] In step S4, the ETFE granules are 75-85 parts by weight;

[0116] The total weight of ETFE powder and ETFE granules is 100 parts, and the melt index of ETFE powder is 18-22 g / min.

[0117] In one specific embodiment, the coupling agent is a fluorinated silane coupling agent;

[0118] The antioxidant is one or more of antioxidant S80, antioxidant 608, or antioxidant 168;

[0119] The dispersant is one or more of PE wax, EBS, and polyester wax;

[0120] The barrier agent is titanium dioxide.

[0121] The method for preparing the curable matting protective composite material provided by this invention involves sequentially preparing agglomerated bulk material, masterbatch, primary modified particles, secondary modified particles, and composite material particles. This ensures that the inorganic filler, which requires a small amount of additive, can be uniformly dispersed in the resin matrix. In particular, the barrier agent, silica, and dispersant are first coated with ETFE powder at a concentration of 18-22 g / min, which further promotes the uniform dispersion of the inorganic filler. The composite material preparation method of this invention is simple and easy to operate, and is readily applicable to the preparation of curable matting protective composite material particles. Detailed Implementation

[0122] The technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0123] The raw materials used in the embodiments of this invention are all commercially available, including:

[0124] ETFE powder (melt index 18-22 g / 10 min), ETFE granules (melt index 8-13 g / 10 min), titanium dioxide, zinc oxide, barium sulfate, silica, fluorinated silane coupling agent (heptadecyltrimethoxysilane), antioxidant S80, antioxidant 608, brightener, whitening agent and dispersant (PE wax).

[0125] The equipment used in the embodiments of this invention is all commercially available, including: high-speed mixer, internal mixer, press, high-speed mixer, and twin-screw granulation extruder.

[0126] Example 1: Preparation of Curing-Free Matte Protective Composite Material

[0127] S1. Preparation of bulk agglomerates: ETFE powder, barrier agent, silica and dispersant are stirred and dispersed in a high-speed mixer. The resulting blended powder is placed in an internal mixer and preheated and melted at 200-230℃ to obtain bulk agglomerates.

[0128] S2. Masterbatch preparation: The lumpy material obtained in step S1 is placed in a press and pressed into uniformly shaped granules, i.e., masterbatch;

[0129] S3. Preparation of primary modified particles: The masterbatch, fluorinated silane coupling agent, antioxidant S80, and antioxidant 608 are mixed in a high-speed mixer, and the temperature is controlled at 25-40℃. The surface of the masterbatch is modified to obtain primary modified particles coated with modifiers and antioxidants.

[0130] S4. Place the primary modified particles and ETFE particles from step S3 into a twin-screw extruder for granulation at a temperature of 225-285℃ to obtain secondary modified particles.

[0131] S5. Preparation of curing-free matte protective composite material: The secondary modified particles obtained in step S4 are placed in a twin-screw extruder for secondary granulation at a temperature of 225-285℃ to obtain curing-free matte protective composite material particles.

[0132] The addition ratio of each material in this embodiment is detailed in Table 1.

[0133] Example 2 and Comparative Examples 1-4

[0134] The composite material preparation processes of Examples 1-2 and Comparative Examples 1-4 are the same as those of Example 1, except that the types and amounts of materials added are different, as detailed in Table 1.

[0135] Table 1

[0136] Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 ETFE Powder 202020202020 ETFE Particles 808080808080 Titanium Dioxide 127.55005 Zinc Oxide 000500 Barium Sulfate 000050 Silica 0.25 0.25 0.25 0.25 0.25 0.25 Fluorosilane Coupling Agent 0.25 0.25 0.25 0.25 0.25 0.25 Antioxidant s800 0.10.10.10.10.10.1 Antioxidant 6080 0.10.10.10.10.10.1 Brightening Agent 00.06 0000 0.06 Whitening Agent 00.02 0000 0.02 Dispersant 0.20.20.20.20.20.20.20.2

[0137] Test case

[0138] The testing method for this test case is as follows:

[0139] Tensile strength and elongation at break were tested according to the test method of GB / T 1040.3-2006. The standard for tensile strength is greater than 35 MPa, and the standard for elongation at break is greater than 300%.

[0140] Roughness was tested using a roughness tester, and the standard roughness range was 0.7-1.3.

[0141] The L-value test is conducted using a colorimeter, and the standard is an L-value greater than 94.

[0142] The appearance of the film is determined by visual inspection, and the standard is good film-forming properties, no pores, and no black spots;

[0143] Heat shrinkage was tested at 180℃ for 30 minutes, with a standard of less than 5%.

[0144] The water contact angle (on the bonding surface) is tested using a water contact angle tester, with a standard range of 50-75°.

[0145] Light transmittance was tested using a light transmittance meter, and the standard was that the light transmittance in the 350-2400nm wavelength range was less than 10%.

[0146] Gloss is tested using a gloss meter, with a standard range of 10°-20°.

[0147] In this test example, the standard selected is the requirement standard for thin films used in communication base stations.

[0148] Test sample preparation: The composite material particles obtained in Examples 1-2 and Comparative Examples 1-4 were extruded into 60μm films using a casting extruder. The extrusion temperature was 275-335℃, and the films were then cooled at 90-150℃ to obtain film samples.

[0149] The samples were tested, and the test results are shown in Table 2:

[0150] Table 2

[0151] Table 2 shows that when the barrier agent is zinc oxide and barium sulfate, the film-forming properties are poor, while when the additive is titanium dioxide, the film-forming properties are good. When the amount of titanium dioxide added is 5 parts by mass, even with the addition of brightener and whitening agent, the L value cannot meet the standard. Although further increasing the amount of brightener and whitening agent helps to increase the L value of the film, it has a significant impact on the film-forming properties. Therefore, the amount of brightener and whitening agent added should not be increased. However, when the amount of titanium dioxide added is increased to 7.5 parts by mass, not only is the film-forming property good, but all tests of the film meet the standard. When the amount of titanium dioxide is further increased to 12 parts by mass, even without the addition of brightener and whitening agent, the L value of the film can meet the standard requirements, but the film surface is rough and has a grainy feel.

[0152] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A curing-free matte protective composite material, characterized in that, Includes the following components in parts by mass: 15-25 parts by weight of ETFE powder; 75-85 parts by weight of ETFE granules; 5.5-12 parts by weight of barrier agent; Brightening agent is either absent or 0.04-0.08 parts by weight; Whitening agent is either not added or 0.01-0.03 parts by weight; 0.2-0.3 parts by weight of silicon dioxide; 0.2-0.3 parts by weight of coupling agent; Dispersant 0.1-0.3 parts by weight; Antioxidant 0.05-0.2 parts by weight; The mixture consists of 100 parts by weight of ETFE powder and ETFE granules, with the ETFE powder having a melt flow index of 18-22 g / min.

2. The composite material of claim 1, wherein, The coupling agent is a fluorinated silane coupling agent; The antioxidant is one or more of antioxidant S80, antioxidant 608, or antioxidant 168; The dispersant is one or more of PE wax, EBS, and polyester wax; The barrier agent is titanium dioxide.

3. The composite material of claim 1, wherein, When the composite material is a 60 μm thick film, it has the following properties: L value is greater than 94; Tensile strength greater than 35 MPa; Elongation at break greater than 300%; Light transmittance is less than 10%.

4. A method for preparing a curing-free matte protective composite material as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Preparation of bulk agglomerates: After the ETFE powder, barrier agent, silica and dispersant are mixed and dispersed evenly, they are preheated and melted in an internal mixer to obtain bulk agglomerates; S2. Masterbatch preparation: The agglomerated bulk material obtained in step S1 is pressed to obtain uniformly shaped granules, i.e., masterbatch; S3. Preparation of primary modified particles: Coupling agent and antioxidant are coated on the surface of the masterbatch obtained in step S2 to obtain modified masterbatch; S4. Preparation of secondary modified particles: The primary modified particles and ETFE particles from step S3 are modified and granulated by a twin-screw granulation extruder to obtain secondary modified particles. S5. Preparation of curing-free matte protective composite material: The secondary modified particles obtained in step S4 are passed through a twin-screw extruder again to obtain curing-free matte protective composite material particles.

5. The preparation method according to claim 4, characterized in that, In step S1, the preheating melting temperature is 200-230℃, and the time is 15-20 min; In step S2, a pressing machine is used for pressing; The initial preparation of modified particles in step S3 is carried out in a high-speed mixer; The temperature for both twin-screw granulation processes in steps S4 and S5 is 225-285℃.

6. The preparation method according to claim 4, characterized in that, In step S1, the amount of ETFE powder is 15-25 parts by weight, the amount of barrier agent is 5.5-12 parts by weight, and the amount of dispersant is 0.1-0.3 parts by weight; In step S3, the coupling agent is 0.2-0.3 parts by weight, and the antioxidant is 0.05-0.2 parts by weight; In step S4, the ETFE granules are 75-85 parts by weight; The total weight of ETFE powder and ETFE granules is 100 parts, and the melt index of ETFE powder is 18-22 g / min.

7. The preparation method according to claim 4, characterized in that, The coupling agent is a fluorinated silane coupling agent; The antioxidant is one or more of antioxidant S80, antioxidant 608, or antioxidant 168; The dispersant is one or more of PE wax, EBS, and polyester wax.

8. The composite material as described in claim 4, characterized in that, Step S1 also includes adding 0.04-0.08 parts by weight of brightening agent and 0.01-0.03 parts by weight of whitening agent.