A reflective laminated film

Abstract

The application relates to the technical field of laminated films, in particular to a reflective laminated film. The reflective laminated film is obtained by alternately laminating A layers and B layers for 20 times or more, wherein the A layer is a layer taking NPG type PETG resin A as a main component, and the B layer is a layer taking a polyester resin B with a higher refractive index than the NPG type PETG resin A as a main component. The application takes the NPG type PETG resin A as the main component of the A layer, the existence of the upper side methyl of the NPG type PETG resin A makes the copolyester molecular chains repel each other, the intermolecular distance is increased, the resistance of the copolyester chain segment to entering the crystal lattice is increased, the possibility of mutual penetration and fusion of the NPG type PETG resin A and the polyester resin B during co-extrusion is reduced, the laminated film has lower haze and higher clarity under the premise of ensuring high reflectivity of the laminated film.

Description

Technical Field

[0001] This application relates to the field of laminated film technology, and more specifically, to a reflective laminated film. Background Technology

[0002] Optical multilayer reflective films are generally formed by alternating layers of two or more organic polymer resins with different refractive indices. Light is selectively reflected and projected through constructive and destructive interference at the interlayer interfaces. Typically, high-refractive-index and low-refractive-index organic polymer resins are alternately layered and extruded into a film using a casting and co-extrusion method.

[0003] By rationally designing the reflective wavelengths of thin films, such as the ultraviolet and visible light bands, the thin films can exhibit certain reflective effects within these wavelength ranges. Thin films with specific wavelength reflectivity can be widely used in electronic displays, automotive windows, building UV and infrared blocking, as well as clothing, packaging, and other fields.

[0004] Currently, CHDM-type PETG is commonly used as the low-refractive-index component in laminated films, which is cast with high-refractive-index polyester resin. However, when CHDM-type PETG resin is co-extruded and cast with polyester resin, the two resin components tend to interpenetrate, resulting in indistinct layer boundaries. This leads to high haze and low clarity in the laminated film, failing to meet the requirements for use. Summary of the Invention

[0005] To improve the problem of high haze in multilayer films, this application provides a reflective multilayer film.

[0006] In a first aspect, this application provides a reflective laminated film, which adopts the following technical solution:

[0007] A reflective laminated film includes an A layer and a B layer, wherein the A layer and the B layer are alternately laminated in more than 20 layers, wherein the A layer is a layer with NPG-type PETG resin A as the main component, and the B layer is a layer with polyester resin B with a refractive index higher than that of NPG-type PETG resin A as the main component.

[0008] By adopting the above technical solution, using NPG-type PETG resin A as the main component of layer A, compared with using CHDM-type PETG resin, the presence of methyl groups on the upper side of NPG-type PETG resin A causes the copolyester molecular chains to repel each other, increasing the intermolecular distance and increasing the resistance of copolyester chain segments to enter the crystal lattice. This reduces the possibility of mutual penetration and fusion when NPG-type PETG resin A and polyester resin B are co-extruded, resulting in lower haze and higher clarity of the laminated film while ensuring high reflectivity.

[0009] Preferably, the refractive index difference between the NPG-type PETG resin A and the polyester resin B is ≥0.03.

[0010] Preferably, the refractive index difference between the NPG-type PETG resin A and the polyester resin B is ≥0.05.

[0011] Preferably, the refractive index difference between the NPG-type PETG resin A and the polyester resin B is ≥0.08.

[0012] Preferably, the B layer comprises the following raw materials in parts by weight: 100 parts polyester resin B and 2-6 parts amino-terminated silane coupling agent modified reflective filler.

[0013] By adopting the above technical solution, the reflective filler modified by terminal aminosilane coupling agent has good dispersibility in layer B, which further improves the reflectivity of the laminated film while reducing the influence of the reflective filler on the haze of the laminated film.

[0014] Preferably, layer A comprises the following raw materials in parts by weight: 100 parts NPG type PETG resin A and 5-12 parts single-hydroxyl-terminated silicone oil modified epoxy resin.

[0015] By adopting the above technical solution, the single-hydroxyl-terminated silicone oil modified epoxy resin contains hydrophobic silicone oil side chains. The presence of hydrophobic side chains, on the one hand, works synergistically with the side methyl groups on NPG-type PETG resin A, further reducing the possibility of mutual penetration and fusion during the co-extrusion of NPG-type PETG resin A and polyester resin B; on the other hand, it improves the compatibility between the modified epoxy resin and NPG-type PETG resin A, further improving the clarity and mechanical properties of the laminated film.

[0016] Preferably, the single-hydroxyl-terminated silicone oil modified epoxy resin has a weight ratio of 8-12 parts.

[0017] Preferably, the single-hydroxyl-terminated silicone oil modified epoxy resin is prepared by reacting single-hydroxyl-terminated silicone oil and epoxy resin in a mass ratio of 1:(10-18).

[0018] By adopting the above technical solution, single-hydroxyl-terminated silicone oil and excess epoxy resin react to generate single-hydroxyl-terminated silicone oil modified epoxy resin. The single-hydroxyl-terminated silicone oil modified epoxy resin also has unreacted active groups. These active groups can bond with the terminal amino silane coupling agent modified reflective filler in layer B, thereby improving the adhesion strength between layer A and layer B and further improving the mechanical properties of the laminated film.

[0019] Preferably, the polyester resin B used in the laminated film is selected from one or more of polyethylene terephthalate and its copolymers, polyethylene naphthalate and its copolymers, polybutylene terephthalate and its copolymers, polybutylene naphthalate and its copolymers, and polyhexamethylene terephthalate and its copolymers and polyhexamethylene naphthalate and its copolymers.

[0020] or,

[0021] The polyester resin B used in the laminated film is obtained by polymerization of monomers with aromatic dicarboxylic acids or aliphatic dicarboxylic acids and diols as the main components.

[0022] Among them, the aromatic dicarboxylic acid is selected from one or more of terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid and 4,4'-diphenyl sulfone dicarboxylic acid;

[0023] Aliphatic dicarboxylic acids, selected from one or more of adipic acid, octanoic acid, sebacic acid, dimer acid, dodecanoic acid, 1,4-cyclohexanedicarboxylic acid and their ester derivatives; among which, terephthalic acid and 2,6-naphthalenedicarboxylic acid, which exhibit high refractive index, are preferred.

[0024] The glycol is selected from one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-cyclohexanediethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis(4-hydroxyethoxyphenyl)propane, isosorbide, and spirocyclic glycol, with ethylene glycol being preferred.

[0025] In summary, this application has the following beneficial effects:

[0026] 1. This application uses NPG-type PETG resin A as the main component of layer A. Compared with CHDM-type PETG resin, the presence of methyl groups on the upper side of NPG-type PETG resin A causes the copolyester molecular chains to repel each other and the intermolecular distance to increase. This increases the resistance of the copolyester chain segments to entering the crystal lattice, reducing the possibility of mutual penetration and fusion when NPG-type PETG resin A and polyester resin B are co-extruded. Under the premise of ensuring high reflectivity of the laminated film, the laminated film has lower haze and higher clarity. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of a square distributor according to an embodiment of this application.

[0028] Figure 2This is the reflectance spectrum of Embodiment 1 of this application.

[0029] Figure 3 This is the reflectance spectrum of Embodiment 2 of this application.

[0030] Figure 4 This is the reflectance spectrum of Embodiment 3 of this application. Detailed Implementation

[0031] Preparation example of reflective filler modified with amino-terminated silane coupling agent

[0032] Preparation Example A

[0033] The amino-terminated silane coupling agent modified reflective filler is prepared according to the following steps:

[0034] Take 1 kg of titanium dioxide (particle size: 40 nm), 3 kg of acetone and 2 kg of terminal aminosilane coupling agent (model: KH-550) and mix them. Disperse them ultrasonically for 1 h, heat to 65 °C and keep the reaction at that temperature for 5 h. Separate and dry the product to obtain the terminal aminosilane coupling agent modified reflective filler.

[0035] Preparation example of epoxy resin modified with single-hydroxyl-terminated silicone oil

[0036] Preparation Example 1

[0037] The epoxy resin modified with single-hydroxyl-terminated silicone oil was prepared according to the following steps:

[0038] Take 100g of single-ended vinyl hydroxyl silicone oil (model: KM-9600), 1kg of epoxy resin (E-20 type) and 15g of sodium hydroxide, mix them, heat to 120℃, and keep the reaction for 2h to obtain single-ended hydroxyl silicone oil modified epoxy resin.

[0039] Preparation Example 2

[0040] The epoxy resin modified with single-hydroxyl-terminated silicone oil was prepared according to the following steps:

[0041] Take 100g of single-ended vinyl hydroxyl silicone oil (model: KM-9600), 1.8kg of epoxy resin (E-20 type) and 15g of sodium hydroxide, mix them, heat to 120℃, and keep the reaction for 2h to obtain single-ended hydroxyl silicone oil modified epoxy resin.

[0042] Preparation Example 3

[0043] The epoxy resin modified with single-hydroxyl-terminated silicone oil was prepared according to the following steps:

[0044] Take 100g of single-ended vinyl hydroxyl silicone oil (model: KM-9600), 1.5kg of epoxy resin (E-20 type) and 15g of sodium hydroxide, mix them, heat to 120℃, and keep the reaction at this temperature for 2h to obtain single-ended hydroxyl silicone oil modified epoxy resin.

[0045] Example

[0046] Example 1

[0047] A reflective laminated film is prepared according to the following steps:

[0048] NPG-type PETG resin A (refractive index 1.57) is layered in a distributor through a casting pipe, and polyester resin B (PET, refractive index 1.60) is layered in another distributor through a casting pipe. The layers are then combined and cross-layered in a composite distributor, and extruded into a film through a T-die. At this stage, electrodes including, but not limited to, linear, strip, or blade-shaped electrodes are used; in this embodiment, blade-shaped electrodes are used. The cast film is pressed tightly against the cooling casting drum by electrostatic force to achieve a rapid cooling effect. This indicates that there are various cooling and curing methods, including but not limited to the following two: direct cooling and curing via a cooling roller, or rapid cooling and curing by blowing cold air from a slit-shaped, dot-shaped, or surface-shaped device. This not only achieves cooling and curing, but the strong airflow also allows the film to adhere more closely to the casting drum. In this embodiment, direct cooling and curing via a cooling roller is used. The distributor can be semi-circular, square, or other shapes suitable for this design concept, as shown in the reference. Figure 1 In this embodiment, a square distributor is selected.

[0049] The film system features a gradient thickness design as follows: The entire optical layer consists of 400 layers, with the thickness stacked linearly, increasing from 87nm in the initial layer to 100nm in the final layer, for a total thickness of 37.4μm. The protective layers on both sides of the optical layer are made of PET with a thickness of 2μm, resulting in an overall film thickness of 41.4μm.

[0050] The thin film's reflectance spectrum was tested and found to be as follows: Figure 2 As shown, the average reflectivity in the visible light 550nm-620nm band is ≥98%.

[0051] Example 2

[0052] A reflective laminated film is prepared according to the following steps:

[0053] NPG-type PETG resin A (refractive index 1.57) is layered in a distributor through a casting pipe, and polyester resin B (PET, refractive index 1.60) is layered in another distributor through a casting pipe. The layers are then combined and cross-layered in a composite distributor, and extruded into a film through a T-die. At this stage, electrodes including, but not limited to, linear, strip, or blade-shaped electrodes are used; in this embodiment, blade-shaped electrodes are used. The cast film is pressed tightly against the cooling casting drum by electrostatic force to achieve a rapid cooling effect. This indicates that there are various cooling and curing methods, including but not limited to the following two: direct cooling and curing via a cooling roller, or rapid cooling and curing by blowing cold air from a slit-shaped, dot-shaped, or surface-shaped device. This not only achieves cooling and curing, but the strong airflow also allows the film to adhere more closely to the casting drum. In this embodiment, direct cooling and curing via a cooling roller is used. The distributor can be semi-circular, square, or other shapes suitable for this design concept, as shown in the reference. Figure 1 In this embodiment, a square distributor is selected.

[0054] The film system features a gradient thickness design as follows: The entire optical layer system consists of 320 layers, with the thickness stacked in a linearly increasing manner, gradually increasing from 61 nm in the initial layer to 103 nm in the final layer, according to a certain linear increase rule, for a total thickness of 26.2 μm. The protective layers on both sides of the optical layer are made of PET with a thickness of 2 μm, resulting in an overall film thickness of 30.2 μm.

[0055] The thin film's reflectance spectrum was tested and found to be as follows: Figure 3 As shown, the average reflectivity in the visible light 400-760nm band is ≥98%.

[0056] Example 3

[0057] A reflective laminated film is prepared according to the following steps:

[0058] NPG-type PETG resin A (refractive index 1.57) is layered in a distributor through a casting pipe, and polyester resin B (PET, refractive index 1.60) is layered in another distributor through a casting pipe. The layers are then combined and cross-layered in a composite distributor, and extruded into a film through a T-die. At this stage, electrodes including, but not limited to, linear, strip, or blade-shaped electrodes are used; in this embodiment, blade-shaped electrodes are used. The cast film is pressed tightly against the cooling casting drum by electrostatic force to achieve a rapid cooling effect. This indicates that there are various cooling and curing methods, including but not limited to the following two: direct cooling and curing via a cooling roller, or rapid cooling and curing by blowing cold air from a slit-shaped, dot-shaped, or surface-shaped device. This not only achieves cooling and curing, but the strong airflow also allows the film to adhere more closely to the casting drum. In this embodiment, direct cooling and curing via a cooling roller is used. The distributor can be semi-circular, square, or other shapes suitable for this design concept, as shown in the reference. Figure 1In this embodiment, a square distributor is selected.

[0059] The film system features a gradient thickness design as follows: The entire optical layer system consists of 150 layers, with the thickness stacked linearly, increasing from 58nm in the initial layer to 69nm in the final layer, according to a specific linear increase rule, for a total thickness of 9.5μm. The protective layers on both sides of the optical layer are made of PET with a thickness of 2μm, resulting in an overall film thickness of 13.5μm.

[0060] The reflectance spectrum of the thin film was tested as follows: Figure 4 As shown in the figure, the average reflectivity in the visible light 380-455nm band is ≥98%.

[0061] Example 4

[0062] A reflective laminated film, which differs from Example 1 in that the refractive index of polyester resin B in this example is 1.62, and the average reflectivity in the visible light 550cm-620nm band is ≥98%.

[0063] Example 5

[0064] A reflective laminated film, which differs from Example 1 in that the refractive index of polyester resin B in this example is 1.65, and the average reflectivity in the visible light 550cm-620nm band is ≥98%.

[0065] Example 6

[0066] A reflective laminated film, which differs from Example 1 in that the polyester resin B is replaced with a B layer material (1000g of polyester resin B and 20g of amino-terminated silane coupling agent modified reflective filler prepared in Example A), with a refractive index of 1.65 and an average reflectivity ≥99% in the visible light band of 550cm-620nm.

[0067] Example 7

[0068] A reflective laminated film, which differs from Example 1 in that the polyester resin B is replaced with a B layer material (1000g of polyester resin B and 60g of amino-terminated silane coupling agent modified reflective filler prepared in Example A), with a refractive index of 1.67 and an average reflectivity ≥99% in the visible light 550cm-620nm band.

[0069] Example 8

[0070] A reflective laminated film, which differs from Example 7 in that, in this example, NPG-type PETG resin A is replaced with A-layer raw material (1000g NPG-type PETG resin A and 50g single-hydroxyl-terminated silicone oil-modified epoxy resin prepared in Preparation Example 1), with a refractive index of 1.57 and an average reflectivity ≥99% in the visible light 550cm-620nm band.

[0071] Example 9

[0072] A reflective laminated film, which differs from Example 7 in that, in this example, NPG-type PETG resin A is replaced with A-layer raw material (1000g NPG-type PETG resin A and 120g single-hydroxyl-terminated silicone oil-modified epoxy resin prepared in Preparation Example 1), with a refractive index of 1.56 and an average reflectivity ≥99% in the visible light 550cm-620nm band.

[0073] Example 10

[0074] A reflective laminated film, which differs from Example 7 in that, in this example, NPG-type PETG resin A is replaced with A-layer raw material (1000g NPG-type PETG resin A and 80g single-hydroxyl-terminated silicone oil-modified epoxy resin prepared in Preparation Example 1), with a refractive index of 1.57 and an average reflectivity ≥99% in the visible light 550cm-620nm band.

[0075] Example 11

[0076] A reflective laminated film, which differs from Example 7 in that, in this example, NPG-type PETG resin A is replaced with A-layer raw material (1000g NPG-type PETG resin A and 50g single-hydroxyl-terminated silicone oil-modified epoxy resin prepared in Preparation Example 2), with a refractive index of 1.57 and an average reflectivity ≥99% in the visible light 550cm-620nm band.

[0077] Example 12

[0078] A reflective laminated film, which differs from Example 7 in that, in this example, NPG-type PETG resin A is replaced with A-layer raw material (1000g NPG-type PETG resin A and 50g single-hydroxyl-terminated silicone oil-modified epoxy resin prepared in Preparation Example 3), with a refractive index of 1.56 and an average reflectivity ≥99% in the visible light 550cm-620nm band.

[0079] Comparative Example

[0080] Comparative Example 1

[0081] A reflective laminated film, which differs from Example 1 in that the NPG type PETG resin A is replaced with CHDM type PETG resin in this example, and the average reflectivity in the visible light 550cm-620nm band is ≤90%.

[0082] Performance testing

[0083] Reflectance measurement of laminated films prepared in the examples and comparative examples: The reflectance of samples cut into 5cm×5cm sections was measured using the integrating sphere attached to the U-4100 Spectrophotomater (manufactured by Hitachi, Ltd.).

[0084] Haze measurement of laminated films prepared in the examples and comparative examples: According to ISO 14782, haze was measured using a haze meter (NDH-7000, manufactured by Nippon Denshoku Kogyo Co., Ltd.) on 15cm × 5cm (75cm) laminated film samples prepared in the examples and comparative examples. 2 The average value at 5 locations was taken as the haze measurement value. The specific test results are shown in Table 1 below:

[0085] Mechanical property testing of laminated films prepared in the examples and comparative examples: The tensile strength of the laminated films was measured according to GB / T1040-2006, and the specific test results are shown in Table 1 below:

[0086] Table 1. Performance Testing of Laminated Membranes

[0087] project Haze (%) Tensile strength (MPa) Example 1 2.3 78.4 Example 2 1.9 70.9 Example 3 2.1 69.3 Example 4 1.8 80.2 Example 5 2.0 79.8 Example 6 2.1 81.3 Example 7 1.9 81.9 Example 8 0.8 89.2 Example 9 0.6 92.1 Example 10 0.5 93.4 Example 11 0.7 91.7 Example 12 0.4 90.6 Comparative Example 1 14.8 75.5

[0088] As can be seen from Table 1, the haze of the laminated film prepared in the embodiments of this application is ≤2.3% and the tensile strength is ≥69.3MPa. This indicates that the laminated film prepared in this application has low haze, high tensile strength, and high reflectivity for light of different wavelengths.

[0089] Combining Example 1 and Comparative Example 1 with Table 1, it can be seen that the haze of the laminated film prepared in Example 1 is much lower than that in Comparative Example 1. This may be because: the raw material for layer A in Example 1 is NPG-type PETG resin, while the raw material for Comparative Example 1 is CHDM-type PETG resin. The presence of methyl groups on the upper side of NPG-type PETG resin A causes the copolyester molecular chains to repel each other, increasing the intermolecular distance and increasing the resistance of the copolyester chain segments to enter the crystal lattice. This reduces the possibility of mutual penetration and fusion when NPG-type PETG resin A and polyester resin B are co-extruded. Under the premise of ensuring high reflectivity of the laminated film, the laminated film has lower haze and higher clarity.

[0090] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A reflective laminated film, characterized in that: It includes an A layer and a B layer, which are stacked alternately in more than 20 layers. The A layer is a layer with NPG-type PETG resin A as the main component, and the B layer is a layer with polyester resin B with a refractive index higher than that of NPG-type PETG resin A as the main component. The refractive index difference between the NPG-type PETG resin A and the polyester resin B is ≥0.03; The B layer comprises the following raw materials in parts by weight: 100 parts polyester resin B, 2-6 parts amino-terminated silane coupling agent modified reflective filler; The A layer comprises the following raw materials in parts by weight: 100 parts NPG type PETG resin A, 5-12 parts single-hydroxyl-terminated silicone oil modified epoxy resin. The single-hydroxyl-terminated silicone oil modified epoxy resin is prepared by reacting single-hydroxyl-terminated silicone oil and epoxy resin in a mass ratio of 1:(10-18).

2. The reflective laminated film according to claim 1, characterized in that: The refractive index difference between the NPG-type PETG resin A and the polyester resin B is ≥0.

05.

3. The reflective laminated film according to claim 2, characterized in that: The refractive index difference between the NPG-type PETG resin A and the polyester resin B is ≥0.

08.

4. A reflective laminated film according to claim 1, characterized in that: The single-hydroxyl-terminated silicone oil modified epoxy resin is 8-12 parts by weight.

Images