Flexible composite weather-resistant layer and preparation method and application thereof

Abstract

The invention provides a flexible composite weather-proof layer and a preparation method and application thereof.The weather-proof layer is sequentially composed of an interface layer, a connecting layer and an anti-aging layer from inside to outside, the interface layer is connected with a base film, the connecting layer is connected with the interface layer, the anti-aging layer is connected with the connecting layer, the thickness of the interface layer is 1-3 microns, and the thickness of the connecting layer is 1-3 microns. The thickness of the connecting layer ranges from 2 micrometers to 3 micrometers, the thickness of the anti-aging layer ranges from 3 micrometers to 6 micrometers, and the total thickness of the weather-proof layer does not exceed 10 micrometers. By optimizing the interface layer formula and adopting the weather-proof layer with a new structure, the interface bonding firmness of the weather-proof layer and the base film is improved, and the layers are mutually infiltrated to form a whole.

Description

Technical Field

[0001] The invention relates to the field of composite materials, and in particular to a flexible composite weather-resistant layer and a preparation method and application thereof. Background Art

[0002] The performance of the multi-layered flexible composite material, as the main component of the airship capsule, will affect the use and application effect of the airship. The weather-resistant layer of the flexible composite material is located on the outermost surface and plays an anti-aging role. The general weather-resistant layer material is polyvinylidene fluoride (PVDF) or polyvinyl fluoride (PVF) film. Among them, PVF film is a thermoplastic resin with excellent performance, excellent chemical resistance, wear resistance, high transparency, anti-aging and corrosion resistance. PVF film has excellent resistance and durability to moisture, oxidation and light. PVDF also has excellent aging resistance. Compared with PVF film, PVDF that has not been low-temperature modified is prone to brittleness in low-temperature environments, and its application in the field of airships is relatively small.

[0003] PVF film, PVDF film and the base film in the flexible composite material are generally connected by adhesives, and the interlayer peel strength is generally 2 to 6N / cm. After repeated use, the weather-resistant layer is prone to debonding and other performance defects between the base film layer; secondly, due to the limitations of the preparation process and equipment, PVF film generally adopts the "paste processing method", and the current equipment can only produce products with thickness specifications of 38μm and 20μm. PVDF film mainly adopts two hot melt processing methods, cast film and blow molding. Films of certain thickness specifications can be processed by adjusting the gap between the equipment die, but the thickness is generally not less than 15μm. It can be seen that PVF film and PVDF film have technical difficulties in interlayer interface performance and thickness lightweighting, which restricts the improvement of interlayer performance of flexible composite materials and the development of lightweight materials. Summary of the invention

[0004] The present invention provides a flexible composite weather-resistant layer and a preparation method and application thereof, wherein an interface layer, a connection layer and an anti-aging layer are sequentially formed by coating the surface of a base film in stages, and the weather-resistant layer is composed of the above three layers. The weather-resistant layer of the present application is used to improve the interface bonding strength between the weather-resistant layer and the base film by optimizing the interface layer formula and using a weather-resistant layer with a new structure, and mutual infiltration occurs between the layers to make the weather-resistant layer a whole.

[0005] In order to solve the above technical problems, the present invention provides a flexible composite weather-resistant layer, which is composed of an interface layer, a connecting layer and an anti-aging layer from the inside to the outside, the interface layer is connected to the base film, the connecting layer is connected to the interface layer, the anti-aging layer is connected to the connecting layer, the thickness of the interface layer is 1μm to 3μm, the thickness of the connecting layer is 2μm to 3μm, the thickness of the anti-aging layer is 3μm to 6μm, and the total thickness of the weather-resistant layer does not exceed 10μm.

[0006] Preferably, the interface layer is a mixture of polyester polyol, isocyanate and organic solvent, and the mixture of polyester polyol, isocyanate and organic solvent has a hydroxyl value of 350-450 KOH·mg / g and an acid value of ≤1.5 KOH·mg / g.

[0007] Preferably, the polyester polyol is an aromatic polyester polyol or a polycaprolactone polyol.

[0008] Preferably, the polycaprolactone polyol is a mixture of polycaprolactone triol and polycaprolactone diol, and the mass ratio of polycaprolactone triol to polycaprolactone diol is 2-3:1.

[0009] Preferably, the isocyanate is triphenylmethane triisocyanate, tris(4-phenylisocyanate)phosphorothioate, dimethyltriphenylmethane tetraisocyanate, isophorone diisocyanate trimer or hexamethylene diisocyanate isocyanurate trimer.

[0010] Preferably, the organic solvent is one or more of acetone, butanone, ethyl acetate and butyl acetate.

[0011] Preferably, the connecting layer is a polycaprolactone aliphatic resin, a polyester aliphatic resin or a polyether aliphatic resin.

[0012] Preferably, the polyether aliphatic resin is prepared by polyol, diisocyanate, chain extender, phenyl silicone rubber and white pigment; the polyol is polytetrahydrofuran, the diisocyanate is HMDI, the chain extender is butanediol, the content of soft segment to hard segment is 2 to 3:1, the hardness of the polyether aliphatic resin is 60A to 75A, the content of phenyl silicone rubber is 1% to 5%, the content of phenyl in silicone rubber is 3% to 5%, and the white pigment is titanium white, lithopone or zinc white, and the content of white pigment is 5% to 10%.

[0013] Preferably, the anti-aging layer is made of a mixture of tetrafluoroethylene resin, a copolymer of fluorinated ethylene and vinyl ether, polyvinyl fluoride or polyvinylidene fluoride resin, aliphatic polyurethane resin or phenyl silicone rubber, and white pigment; the addition ratio of the aliphatic polyurethane resin or phenyl silicone rubber is ≤30%; the addition ratio of the white pigment is 5% to 10%, wherein the white pigment is titanium white, lithopone or zinc white.

[0014] Based on the same inventive concept, the present invention also provides a method for preparing a flexible composite weather-resistant layer, comprising the following steps:

[0015] S1: Apply the interface layer on the surface of the base film, fully stir the components, the stirring time is 5min to 30min, and the apparent viscosity is controlled at 500cps to 3200cps; the drying temperature of the weather-resistant layer is 50℃ to 80℃, and the drying time is 0.5min to 5min;

[0016] S2: Apply a layer of aliphatic polyurethane resin on the surface of the interface layer to form a connecting layer, and fully stir the components for 5 to 10 minutes, and the apparent viscosity is controlled at 1500cps-4500cps; the drying temperature of the weather-resistant layer is 60℃~100℃, and the drying time is 0.5~5min;

[0017] S3: Apply an anti-aging layer on the surface of the connecting layer, fully stir the components, and control the apparent viscosity of the system at 2000cps~5000cps; the stirring time is 5min to 30min; the drying temperature of the weather-resistant layer is 60℃~100℃, and the drying time is 0.5~5min.

[0018] The present invention also provides an application of a flexible composite weather-resistant layer, wherein the flexible composite weather-resistant layer is used for an airship skin.

[0019] The above one or more technical solutions of the present invention have at least one or more of the following technical effects:

[0020] The invention provides a flexible composite weather-resistant layer and a preparation method and application thereof. The peel strength between the weather-resistant layer and the base film layer is not less than 6N / cm or the interlayer damage form is bulk damage. A mixed liquid of isocyanate and polyurethane polyol is coated on the surface of the base film to strengthen the interlayer fastness between the weather-resistant layer and the base film. Secondly, a highly elastic aliphatic polyurethane resin is arranged between the interface layer and the anti-aging layer to form a connecting layer, which can connect and buffer the anti-aging layer and improve the multiple bending and flexing performance of the flexible composite material. Fluorocarbon resin is used as the anti-aging layer. The fluorocarbon resin has excellent weather resistance and can be used outdoors for more than 20 years. At the same time, a small proportion (less than 30%) of aliphatic polyurethane resin needs to be mixed in the fluorocarbon resin to further improve the flexing performance of the weather-resistant layer, so that the flexing times of the weather-resistant layer are greater than 5000 times and the appearance is intact. By adding a certain proportion of white pigment to the connecting layer and the anti-aging layer, the weather-resistant layer is made opaque in the ultraviolet and visible light regions; and by optimizing the raw materials for the preparation of the interface layer, the connecting layer and the anti-aging layer, the proposed weather-resistant layer has good aging resistance. Compared with the currently used single-layer PVF film and PVDF film weather-resistant layer system, the proposed weather-resistant layer has obvious advantages in interlayer fastness, deflection, rubbing and lightweight surface density. And by adjusting the coating thickness, weather-resistant layers of different thicknesses can be prepared, which is more flexible in the lightweight design and preparation of weather-resistant layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 , schematic diagram of the structure of the flexible composite weather-resistant layer;

[0022] Among them: 1-interface layer, 2-connection layer, 3-anti-aging layer, 4-weather-resistant layer. DETAILED DESCRIPTION

[0023] An embodiment of the present invention provides a flexible composite weather-resistant layer, which is composed of an interface layer, a connecting layer and an anti-aging layer from the inside to the outside, the interface layer is connected to the base film, the connecting layer is connected to the interface layer, the anti-aging layer is connected to the connecting layer, the thickness of the interface layer is 1μm to 3μm, the thickness of the connecting layer is 2μm to 3μm, the thickness of the anti-aging layer is 3μm to 6μm, and the total thickness of the weather-resistant layer does not exceed 10μm.

[0024] The following is a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the obtained embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0025] Example 1

[0026] The weather-resistant layer is composed of anti-aging layer / connecting layer / interface layer from outside to inside, the base film is PET, and the film thickness ranges from 5 to 50μm. Among them, the interface layer is polycaprolactone polyol, polycaprolactone triol and polycaprolactone diol, the mixing ratio is 2:1, 5% thiophosphate tris (4-phenyl isocyanate) is added, the organic solvent content is 20%, and the total thickness of the interface layer is 1μm; the connecting layer is polyether aliphatic polyurethane, the soft segment and hard segment content ratio is 2:1, 1% phenyl silicone rubber is mixed in the system, and the hardness of the polyurethane resin is 70A; titanium dioxide (TiO2) white pigment is added to the connecting layer, the addition ratio is 5%, and the organic solvent content is 15%; the thickness of the connecting layer is 3μm; the main component of the anti-aging layer is FEVE, and 20% phenyl silicone rubber is added to the FEVE resin, the thickness of the anti-aging layer is 3μm, and the total thickness of the weather-resistant layer is 7μm.

[0027] Preparation process: the first step is to add 5% tris(4-phenylisocyanate)thiophosphate and 20% ethyl acetate to the polycaprolactone polyol system and stir them thoroughly for 10 minutes. The apparent viscosity is 1700cps. The organic solvent is ethyl acetate and butyl acetate, which are prepared in a ratio of 1:2. The drying temperature of the interface layer is 60°C, 70°C, 80°C and 90°C, and the drying time is 5 minutes. The second step is to mix polyether aliphatic polyurethane, 1% phenyl silicone rubber, 5% titanium dioxide, 10% ethyl acetate and 5% ether into a mixed solution. The agent is fully stirred for 10 minutes, the apparent viscosity is 2500cps, the drying temperature of the connecting layer is 60℃, 70℃, 80℃ and 90℃, and the drying time is 5min; the main components of the anti-aging layer are fluoroFEVE resin and phenyl silicone rubber, the addition ratio of phenyl silicone rubber is 20%, and a mixed solvent of 10% ethyl acetate and 15% ether is added, the stirring time is 30min, and the apparent viscosity is 3000cps; the drying temperature of the anti-aging layer is 60℃, 70℃, 80℃ and 90℃, and the drying time is 5min.

[0028] The weather-resistant layer prepared by the above method was subjected to a performance test. The surface density of the weather-resistant layer was 11 g / m 2 (GB / T4669), UV transmittance is 0 (GB / T2680), visible light transmittance is 0.151% (GB / T2680), interlayer peel strength is 15N / cm (GB8808), the weather-resistant layer does not fall off after flexing 5000 times, the appearance is intact, and there is no leakage after ink application (QB / T 2714-2018). The weather-resistant layer was tested for solar reflectance and absorption ratio, and the solar reflectance was 0.56% (GJB 2502.2), and the solar absorption ratio was 0.10% (GJB 2502.2). After 56d 1120W / m 2 Solar radiation accelerates aging. After aging, the weather-resistant layer has a good appearance without cracking, powdering and other performance defects (GJB 8177).

[0029] Example 2

[0030] The weather-resistant layer is composed of anti-aging layer / connecting layer / interface layer from outside to inside, the base film is PET, and the film thickness ranges from 5 to 50μm. Among them, the interface layer is polycaprolactone polyol, in which the mixing ratio of polycaprolactone triol and polycaprolactone diol is 2.5:1, the content of tri(4-phenylisocyanate) thiophosphate is 5%, the content of butyl acetate is 20%, and the total thickness of the interface layer is 2μm. The connecting layer is polyether aliphatic polyurethane, in which the ratio of soft segment to hard segment is 2:1, 5% phenyl silicone rubber and 5% titanium dioxide (TiO2) white pigment are mixed in the system, the hardness of the polyurethane resin is 65A, and the thickness of the connecting layer is 2μm; the main component of the anti-aging layer is FEVE, 15% phenyl silicone rubber is added to the FEVE resin, the thickness of the anti-aging layer is 5μm, and the total thickness of the weather-resistant layer is 9μm.

[0031] Preparation process: the first step is to add 5% tris(4-phenylisocyanate)thiophosphate and 25% ethyl acetate to the polycaprolactone polyol system and stir them fully for 10 minutes. The apparent viscosity is 1500cps. The interface layer is coated on the surface of the base film. The interface layer is dried in stages. The drying temperatures are 60°C, 70°C, 80°C and 90°C respectively. The drying time is 5 minutes. After drying, the film is rolled up with a supercooled roller. The second step is to stir polyether aliphatic polyurethane, 1% phenyl silicone rubber, 5% titanium dioxide, 15% ethyl acetate and 20% ether fully for 10 minutes. The apparent viscosity of the system after stirring is 1500cps. The viscosity of the connecting layer is 3000cps, and the drying temperature of the connecting layer is 60℃, 70℃, 80℃ and 90℃ respectively, and the drying time is 5min, ensuring that there is only a small amount of solvent. After drying, the film is rolled up by a supercooled roller. The main components of the anti-aging layer are FEVE resin and phenyl silicone rubber, of which the addition ratio of phenyl silicone rubber is 15%, and a mixed solvent of 10% ethyl acetate and 5% ether is added. It is fully stirred for 30min, and the apparent viscosity is 3000cps. The drying temperature of the anti-aging layer is 60℃, 70℃, 80℃ and 90℃, and the drying time is 5min. After drying, the film is rolled up by a supercooled roller.

[0032] The performance of the weather-resistant layer prepared by the above method was tested. The surface density of the weather-resistant layer was 10 g / m 2(GB / T4669), UV transmittance is 0 (GB / T2680), visible light transmittance is 0.176% (GB / T2680), interlayer peeling strength is bulk destruction (GB8808), the weather-resistant layer does not fall off after flexing 5000 times, the appearance is intact, and there is no leakage after ink application (QB / T 2714-2018). The weather-resistant layer was tested for solar reflectance and absorption ratio, and the solar reflectance was 0.54% (GJB2502.2), and the solar absorption ratio was 0.14% (GJB 2502.2). After 56d 1120W / m 2 After accelerated aging by solar radiation, the weather-resistant layer has a good appearance without cracking, powdering and other performance defects (GJB 8177).

[0033] Comparative Example

[0034] The flexible composite material is weather-resistant layer / glue layer / PET / glue layer / aromatic polyester fiber woven fabric / thermoplastic polyurethane TPU from outside to inside. Among them, the weather-resistant layer is PVDF film, the weather-resistant layer thickness is 20μm, and it is white. The weather-resistant layer is connected to the base film PET through the glue layer. The performance test of the above weather-resistant layer shows that the surface density of the weather-resistant layer is 25g / m 2 (GB / T 4669), UV transmittance is 0 (GB / T2680), visible light transmittance is 0.126% (GB / T2680), interlayer peel strength is 13N / cm (GB8808), the weather-resistant layer has no peeling after 5000 flexures, there are fine cracks, and leakage occurs after ink is applied (QB / T 2714-2018). The weather-resistant layer is tested for solar reflectance and absorption ratio, and the solar reflectance is 0.59% (GJB2502.2), and the solar absorption ratio is 0.12% (GJB 2502.2). After 56d1120W / m 2 After accelerated aging by solar radiation, the weather-resistant layer has a good appearance without cracking, powdering and other performance defects (GJB 8177).

Claims

1. A flexible composite weather-resistant layer, characterized in that: The weather-resistant layer is composed of an interface layer, a connecting layer and an anti-aging layer from the inside to the outside, the interface layer is connected to the base film, the connecting layer is connected to the interface layer, the anti-aging layer is connected to the connecting layer, the thickness of the interface layer is 1μm to 3μm, the thickness of the connecting layer is 2μm to 3μm, the thickness of the anti-aging layer is 3μm to 6μm, and the total thickness of the weather-resistant layer does not exceed 10μm.

2. The flexible composite weather-resistant layer according to claim 1, characterized in that: The interface layer is a mixture of polyester polyol, isocyanate and organic solvent, wherein the mixture has a hydroxyl value of 350-450 KOH·mg / g and an acid value of ≤1.5 KOH·mg / g.

3. The flexible composite weather-resistant layer according to claim 2, characterized in that: The polyester polyol is an aromatic polyester polyol or a polycaprolactone polyol.

4. The flexible composite weather-resistant layer according to claim 3, characterized in that: The polycaprolactone polyol is a mixture of polycaprolactone triol and polycaprolactone diol, and the mass ratio of polycaprolactone triol to polycaprolactone diol is 2-3:

1.

5. The flexible composite weather-resistant layer according to claim 2, characterized in that: The isocyanate is triphenylmethane triisocyanate, tri(4-phenylisocyanate)phosphorothioate, dimethyltriphenylmethane tetraisocyanate, isophorone diisocyanate trimer or hexamethylene diisocyanate isocyanurate trimer.

6. The flexible composite weather-resistant layer according to claim 2, characterized in that: The organic solvent is one or more of acetone, butanone, ethyl acetate and butyl acetate.

7. The flexible composite weather-resistant layer according to claim 1, characterized in that: The connecting layer is a polycaprolactone aliphatic resin, a polyester aliphatic resin or a polyether aliphatic resin.

8. The flexible composite weather-resistant layer according to claim 7, characterized in that: The polyether aliphatic resin is prepared by polyol, diisocyanate, chain extender, phenyl silicone rubber and white pigment; the polyol is polytetrahydrofuran, the diisocyanate is HMDI, the chain extender is butanediol, the content of soft segment to hard segment is 2-3:1, the hardness of the polyether aliphatic resin is 60A-75A, the content of phenyl silicone rubber is 1%-5%, the content of phenyl in silicone rubber is 3%-5%, the white pigment is titanium white, zinc barium white or zinc white, and the content of white pigment is 5%-10%.

9. The flexible composite weather-resistant layer according to claim 1, characterized in that: The anti-aging layer is made of a mixture of tetrafluoroethylene resin, a copolymer of fluorinated ethylene and vinyl ether, polyvinyl fluoride or polyvinylidene fluoride resin, aliphatic polyurethane resin or phenyl silicone rubber, and white pigment; the addition ratio of the aliphatic polyurethane resin or phenyl silicone rubber is ≤30%; the addition ratio of the white pigment is 5% to 10%, wherein the white pigment is titanium white, lithopone or zinc white.

10. A method for preparing the flexible composite weather-resistant layer according to any one of claims 1 to 8, characterized in that: The steps include: S1: Apply the interface layer on the surface of the base film, fully stir the components, the stirring time is 5min to 30min, and the apparent viscosity is controlled at 500cps to 3200cps; the drying temperature of the weather-resistant layer is 50℃ to 80℃, and the drying time is 0.5min to 5min; S2: Apply a layer of aliphatic polyurethane resin on the surface of the interface layer to form a connecting layer, and fully stir the components for 5 to 10 minutes, and the apparent viscosity is controlled at 1500cps-4500cps; the drying temperature of the weather-resistant layer is 60℃~100℃, and the drying time is 0.5~5min; S3: Apply an anti-aging layer on the surface of the connecting layer, fully stir the components, and control the apparent viscosity of the system at 2000cps~5000cps; the stirring time is 5min to 30min; the drying temperature of the weather-resistant layer is 60℃~100℃, and the drying time is 0.5~5min.

11. An application of the flexible composite weather-resistant layer according to any one of claims 1 to 8, characterized in that: The flexible composite weather-resistant layer is used for the airship skin.

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