A highly reflective flash-spun film

Abstract

The present application relates to a kind of high-reflective flash spinning film, the raw material of flash spinning film includes polyethylene, in the wavelength range of visible light 350~800 nanometer, the reflectivity of unit fineness of flash spinning film is 0.22~0.99 microns ‑1 ;Unit fineness reflectivity=reflectivity / average diameter of fiber;The testing method of reflectivity is:ISO 9050:2003.The flash spinning film of the present application has higher reflective performance, especially as the technical field of agricultural mulch.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thin films, in particular to a high-reflectivity flash-spun film. BACKGROUND

[0002] Common high-reflective thin flash-spun film materials mainly include the following types and reflection mechanisms:

[0003] (1) Metal reflective film, common types: common types include aluminum film, silver film, gold film, etc. Reflection mechanism: mainly based on collective oscillation of free electrons, i.e., plasmon resonance. When light is incident on the metal surface, the free electrons in the metal will undergo collective oscillation under the action of the electric field. This oscillation will interact with the incident light, causing most of the light to be reflected back. Metals have high electrical conductivity and can quickly respond to changes in electric field, thereby producing strong reflection of light. For example, silver has extremely high reflectivity in the visible light range, because the free electron density of silver is high and the plasmon resonance frequency matches well with the frequency of visible light.

[0004] (2) Dielectric reflective film, common types: multilayer film structures made of dielectric materials such as titanium dioxide (TiO2) and silicon dioxide (SiO2). Mechanism: uses optical interference principle. Different refractive index dielectric materials are alternately stacked to form a multilayer film structure, when light propagates in these film layers, reflection and transmission will occur at different interfaces. By precisely designing the thickness and refractive index of the film layers, the light of a specific wavelength can be made to produce constructive interference between the reflected light at each layer, thereby achieving high reflectivity. The multilayer film composed of high and low refractive index dielectric materials alternately, when light is incident, the reflected light at each interface will be superimposed in phase according to the relationship between the film layer thickness and the refractive index, enhancing the reflection effect at certain specific wavelengths.

[0005] (3) Metal-dielectric composite reflective film, types: composed of metal layers and dielectric layers. Reflection mechanism: combines the reflection characteristics of metals and dielectrics. The metal layer provides high initial reflectivity, while the dielectric layer can further enhance reflection or improve other characteristics by adjusting optical properties. Covering a layer of appropriate dielectric material on the metal surface can reduce oxidation and scattering of the metal surface, improve the stability of reflectivity. At the same time, the dielectric layer can also play the role of protecting the metal layer, adjusting the reflection spectrum range, etc.

[0006] (4) Plastic film, material is normal PE, PVC, etc., the feature is: uniform thickness; Ensure the consistency of coverage, so that the soil receives more uniform heat preservation, water retention, etc. Generally speaking, the thickness of plastic film is usually in the tens of microns. Plastic film can adapt to different terrain farmland, not easy to break or damage during laying, can be stretched and covered conveniently, fit the ups and downs of the ground, ensure good coverage effect. But the reflectivity of plastic film is not very high, which is a common problem of plastic film, which should be due to the preparation process of extrusion stretching process, the reflectivity is not high, which is one of the defects of the application of plastic film.

[0007] However, the application is completely different from the preparation process of traditional high-emission film, and has a different way, using flash process to spin polyethylene raw material, and then film, using the ordered characteristics of flash fiber in the film distribution to obtain good reflection effect, especially in the field of agricultural mulch has wide application prospect. SUMMARY

[0008] The purpose of the present application is to overcome the technical problem of low reflectivity of flash spun film used in the field of agricultural mulch, and to provide a high-reflective flash spun film.

[0009] The purpose of the present application is achieved by the following technical solutions:

[0010] A high-reflective flash spun film, the raw material of the flash spun film comprises polyethylene, in the wavelength range of 350-800 nanometers of visible light, the reflectivity of the flash spun film per unit fineness is 0.22-0.99 microns -1 ;

[0011] The reflectivity per unit fineness = reflectivity / average diameter of the fiber;

[0012] The test method of reflectivity is ISO 9050:2003.

[0013] The reflectivity per unit fineness of the flash spun film is 0.22-0.32 microns -1 .

[0014] The reflectivity per unit fineness of the flash spun film is 0.32-0.42 microns -1 .

[0015] The reflectivity per unit fineness of the flash spun film is 0.42-0.52 microns -1 .

[0016] The reflectivity per unit fineness of the flash spun film is 0.52-0.62 microns -1 .

[0017] The reflectivity per unit fineness of the flash spun film is 0.62-0.72 microns -1 .

[0018] The reflectivity of the flash-spun film per unit fineness is 0.72-0.82 microns -1 .

[0019] The reflectivity of the flash-spun film per unit fineness is 0.82-0.92 microns -1 .

[0020] The reflectivity of the flash-spun film per unit fineness is 0.92-0.99 microns -1 .

[0021] The reflectivity of the flash-spun film per unit fineness is 0.92-0.99 microns

[0022] The reflectivity of the flash-spun film per unit fineness is 0.92-0.99 microns

[0023] The reflectivity of the flash-spun film per unit fineness is 0.92-0.99 microns

[0024] The reflectivity of the flash-spun film per unit fineness is 0.92-0.99 microns

[0025] The reflectivity of the flash-spun film per unit fineness is 0.92-0.99 microns

[0026] A processing method of a high-reflectivity flash-spun film, characterized in that it comprises the following technical steps:

[0027] (1) dissolving a polymer in a spinning solvent to form a spinning solution; the mass fraction of the polymer in the spinning solution is 7-16%;

[0028] wherein the polymer is polyethylene or the like; the spinning solvent is aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, unsaturated hydrocarbons, halogenated hydrocarbons, alcohols, esters, ethers, ketones, nitriles, amides, fluorocarbons, sulfur dioxide, carbon disulfide, nitromethane, water, and a mixture of one or more of the above;

[0029] (2) flash-spinning the spinning solution obtained in step (1) through a spinning assembly to obtain flash-spun fibers, and then performing webbing and hot rolling to obtain a high-reflectivity flash-spun film;

[0030] wherein the spinneret of the spinning assembly is arranged in three layers, wherein the upper layer has three spinning holes, the middle layer has four spinning holes, and the lower layer has three spinning holes; and the size of each spinning hole is the same, and the diameter of the spinning hole is 0.075-0.1 mm.

[0031] In the hot rolling process, the hot rolling temperature is controlled at 105-115℃, the hot rolling pressure is controlled at 0.5-2MPa, and the hot rolling time is controlled at 10-30s.

[0032] When the hot rolling pressure and the shorter time (less than 1MPa, less than 10s) obtain the lower unit fineness reflectivity less than 0.22 microns -1 The main reasons are: (1) the limited degree of fiber combination: the lower hot rolling pressure makes the combination between the flash fibers not tight enough, and there are still more gaps and relatively independent structures between the fibers. The shorter hot rolling time is also not enough for the fibers to fully fuse and deform, and the fibers basically maintain the initial state after flash spinning. This relatively loose structure is not conducive to multiple reflection and scattering of light, and light can easily penetrate the gaps between the fibers, so that the amount of light participating in reflection is relatively small, resulting in lower reflectivity. (2) The fiber surface morphology changes little: under such hot rolling conditions, the fiber surface is subjected to limited pressure and action time, and its surface morphology does not change significantly, still maintaining a certain roughness and irregularity. This not very smooth surface will cause light to be diffusely reflected when reflected, and part of the light will be scattered in different directions, which cannot form concentrated and high-intensity reflection, thereby resulting in lower unit fineness reflectivity.

[0033] With the increase of the spinneret hole, the internal structure of the fiber becomes more loose or uneven. When light is incident on the fiber, more light will enter the fiber and be scattered and absorbed, resulting in a decrease in reflected light, which leads to a decrease in reflectivity, and ultimately a significant decrease in the unit fineness reflectivity of the product.

[0034] Compared with the prior art, the positive effects of the present application are:

[0035] The present application adopts the design of this spinneret and precisely controls the hot rolling process parameters, which can make the diameter of the flash fiber finer and the combination state between the fibers better, which is conducive to the reflection of light and meets the demand for higher reflectivity in the field of agricultural mulch. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The schematic diagram of the spinneret of the present application.

[0037] The marks in the drawings are: 1 is the spinneret hole. DETAILED DESCRIPTION

[0038] The following provides a specific embodiment of a high-reflective flash spun film of the present application.

[0039] Example 1

[0040] A processing method of a high-reflective flash spun film, which comprises the following technical steps:

[0041] (1) The polymer is dissolved in a spinning solvent to form a spinning solution; the mass fraction of the polymer in the spinning solution is 7%;

[0042] The polymer is polyethylene;

[0043] The spinning solvent is cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1H-perfluoroheptane, and 1,1,1,3,3-pentafluorobutane, with a mass ratio of 5:3:1:1.

[0044] (2) The spinning solution obtained in step (1) is flash spun through the spinning assembly at a temperature of 220±5℃ to obtain flash fiber, which is then laid into a web and hot rolled at a temperature of 110±3℃ to obtain a high-reflectivity flash spun film.

[0045] Among them, such as Figure 1 As shown, the spinneret of the spinning assembly is arranged in three layers, with three spinneret holes 1 in the upper layer, four spinneret holes 1 in the middle layer, and three spinneret holes 1 in the lower layer; and each spinneret hole 1 has the same size, with a diameter of 0.085 mm.

[0046] During the hot rolling process, the hot rolling temperature is controlled at 110℃, the hot rolling pressure is controlled at 0.6MPa, and the hot rolling time is controlled at 12s.

[0047] Example 2

[0048] A method for processing a high-reflectivity spun film, comprising the following technical steps:

[0049] (1) The polymer is dissolved in a spinning solvent to form a spinning solution; the mass fraction of the polymer in the spinning solution is 10%;

[0050] The polymer is polyethylene;

[0051] The spinning solvent is cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1H-perfluoroheptane, and 1,1,1,3,3-pentafluorobutane, with a mass ratio of 5:3:1:1.

[0052] (2) The spinning solution obtained in step (1) is flash spun through the spinning assembly at a temperature of 220±5℃ to obtain flash fiber, which is then laid into a web and hot rolled at a temperature of 110±3℃ to obtain a high-reflectivity flash spun film.

[0053] Among them, such as Figure 1 As shown, the spinneret of the spinning assembly is arranged in three layers, with three spinneret holes 1 in the upper layer, four spinneret holes 1 in the middle layer, and three spinneret holes 1 in the lower layer; and each spinneret hole has the same size, with a diameter of 0.085 mm.

[0054] During the hot rolling process, the hot rolling temperature is controlled at 110℃, the hot rolling pressure is controlled at 1.4MPa, and the hot rolling time is controlled at 19s.

[0055] Example 3

[0056] A method for processing a high-reflectivity spun film, comprising the following technical steps:

[0057] (1) The polymer is dissolved in a spinning solvent to form a spinning solution; the mass fraction of the polymer in the spinning solution is 13%;

[0058] The polymer is polyethylene;

[0059] The spinning solvent is cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1H-perfluoroheptane, and 1,1,1,3,3-pentafluorobutane, with a mass ratio of 5:3:1:1.

[0060] (2) The spinning solution obtained in step (1) is flash spun through the spinning assembly at a temperature of 220±5℃ to obtain flash fiber, which is then laid into a web and hot rolled at a temperature of 110±3℃ to obtain a high-reflectivity flash spun film.

[0061] Among them, such as Figure 1 As shown, the spinneret of the spinning assembly is arranged in three layers, with three spinneret holes 1 in the upper layer, four spinneret holes 1 in the middle layer, and three spinneret holes 1 in the lower layer; and each spinneret hole has the same size, with a diameter of 0.085 mm.

[0062] During the hot rolling process, the hot rolling temperature is controlled at 110℃, the hot rolling pressure is controlled at 2MPa, and the hot rolling time is controlled at 28s.

[0063] Comparative Example 1

[0064] A method for processing a high-reflectivity spun film, comprising the following technical steps:

[0065] (1) The polymer is dissolved in a spinning solvent to form a spinning solution; the mass fraction of the polymer in the spinning solution is 10%;

[0066] The polymer is polyethylene;

[0067] The spinning solvent is cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1H-perfluoroheptane, and 1,1,1,3,3-pentafluorobutane, with a mass ratio of 5:3:1:1.

[0068] (2) The spinning solution obtained in step (1) is flash spun through the spinning assembly at a temperature of 220±5℃ to obtain flash fiber, which is then laid into a web and hot rolled at a temperature of 110±3℃ to obtain a high-reflectivity flash spun film.

[0069] Among them, such as Figure 1 As shown, the spinneret of the spinning assembly is arranged in three layers, with three spinneret holes 1 in the upper layer, four spinneret holes 1 in the middle layer, and three spinneret holes 1 in the lower layer; and each spinneret hole has the same size, with a diameter of 0.085 mm.

[0070] During the hot rolling process, the hot rolling temperature is controlled at 110℃, the hot rolling pressure is controlled at 0.3MPa, and the hot rolling time is controlled at 5s.

[0071] Comparative Example 2

[0072] A method for processing a high-reflectivity spun film, comprising the following technical steps:

[0073] (1) The polymer is dissolved in a spinning solvent to form a spinning solution; the mass fraction of the polymer in the spinning solution is 10%;

[0074] The polymer is polyethylene;

[0075] The spinning solvent is cis-1,2-dichloroethylene, trans-1,2-dichloroethylene, 1H-perfluoroheptane, and 1,1,1,3,3-pentafluorobutane, with a mass ratio of 5:3:1:1.

[0076] (2) The spinning solution obtained in step (1) is flash spun through the spinning assembly at a temperature of 220±5℃ to obtain flash fiber, which is then laid into a web and hot rolled at a temperature of 110±3℃ to obtain a high-reflectivity flash spun film.

[0077] Among them, such as Figure 1 As shown, the spinneret of the spinning assembly is arranged in three layers, with three spinneret holes 1 in the upper layer, four spinneret holes 1 in the middle layer, and three spinneret holes 1 in the lower layer; and each spinneret hole has the same size, with a diameter of 0.15 mm.

[0078] During the hot rolling process, the hot rolling temperature is controlled at 110℃, the hot rolling pressure is controlled at 1.4MPa, and the hot rolling time is controlled at 19s.

[0079]

[0080] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the concept of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A highly reflective flash-spun film characterized in that, The raw material of the flash-spun film contains polyethylene, and the reflectivity of the flash-spun film per unit fineness is 0.22-0.99 micrometers in the wavelength range of 350-800 nanometers of visible light -1 ; Reflectivity of unit fineness = Reflectivity / average diameter of fiber; The testing method of reflectivity is ISO 9050:2003.

2. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film is 0.22 to 0.32 microns per unit fineness -1 .

3. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film is 0.32 to 0.42 microns per unit fineness -1 .

4. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film was 0.42-0.52 microns per unit denier -1 .

5. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film was 0.52-0.62 microns per unit denier -1 .

6. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film was 0.62-0.72 microns per unit denier -1 .

7. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film is 0.72 to 0.82 microns per unit fineness -1 .

8. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film was 0.82 to 0.92 microns per unit fineness -1 .

9. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash-spun film is 0.92 to 0.99 microns per unit fineness -1 .

10. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash spinning film is 0.89-0.99 in the range of 350-800 nm of visible light wavelength.

11. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash spinning film is 0.89-0.92 in the range of 350-800 nm of visible light wavelength.

12. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash spinning film is 0.92-0.95 in the range of 350-800 nm of visible light wavelength.

13. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash spinning film is 0.95-0.97 in the range of 350-800 nm of visible light wavelength.

14. A high reflective flash spun film as claimed in claim 1, wherein, The reflectivity of the flash spinning film is 0.97-0.99 in the range of 350-800 nm of visible light wavelength.

15. The method for processing a high-reflectivity spun film as described in claim 1, characterized in that, The technical steps thereof are: (1) dissolving the polymer in a spinning solvent to form a spinning solution; the mass fraction of the polymer in the spinning solution is 7-16%; (2) the spinning solution obtained in step (1) is subjected to flash spinning through a spinning assembly to obtain flash fibers, and then is subjected to web laying and hot rolling to obtain a high-reflectivity flash spinning film; The spinning assembly has a spinneret arranged in three layers, wherein the upper layer has three spinning holes, the middle layer has four spinning holes, and the lower layer has three spinning holes; and the size of each spinning hole is the same.

16. A method of processing a high reflective flash spun film as claimed in claim 15, wherein, The diameter of the spinning hole is 0.075-0.1 mm; in the hot rolling process, the hot rolling temperature is controlled at 105-115 ℃, the hot rolling pressure is controlled at 0.5 MPa-2 MPa, and the hot rolling time is controlled at 10-30 s.

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