TW202019993A - Curable compositions for forming light scattering layers - Google Patents

Abstract

Curable compositions include at least one fluoropolymer, at least one monofunctional (meth)acrylate, at least one difunctional (meth)acrylate, and at least one initiator. The curable composition, when cured, forms an optically-scattering layer including a matrix and phase separated microdomains. The matrix and the phase separated microdomains have different refractive indices, and the microdomains are on the order of or larger than the wavelengths of visible light.

Description

Curable composition for forming light scattering layer

The present disclosure relates to an optical light scattering layer formed of a curable polymer composition.

Optical devices are becoming increasingly more complex and involve more and more multi-functional layers. As light travels through the layers of the optical device, the layers can change the light in a wide variety of ways. For example, light can be reflected, refracted, or absorbed. Layers are often included in optical devices for more than one purpose. For example, a layer used as a spacer layer to separate two layers (which are mechanical functions) may also be required to provide optical functions (such as transmitted or diffused light).

An optical function of the organic layer used is for light diffusion. For example, optical devices include information displays, such as liquid crystal displays and rear projection screens. These devices usually rely on optical construction of light diffusion to facilitate efficient operation and enhance readability. Without significantly compromising the intensity of forward scattered light, such light diffusion structures play a key role in these displays by forward scattering light from the light source. The resulting scattered, but high-transmittance light gives such displays the desired background brightness by reducing the amount of incident light that is scattered or reflected back to the light source. The elimination or limitation of this "backscattered" light is a key factor in the design of these light diffusion structures. The diffuser can be incorporated into the optical system by adding additional diffuser components to the system, or in some cases by incorporating diffuse properties into existing components.

Adding additional components to the optical system has the disadvantage of introducing additional absorption and generating additional interfaces that can reflect light, resulting in loss of illumination and other forms of image degradation. In addition, in some multi-layer systems, it may be difficult or impossible to add additional components.

The present disclosure relates to an optical light scattering layer formed of a curable polymer composition. Described herein are curable compositions, articles made with these curable compositions, and methods of forming optical articles.

The curable composition of the present disclosure includes at least one fluoropolymer, at least one monofunctional (meth)acrylate, at least one difunctional (meth)acrylate, and at least one initiator. In this disclosure, the terms "curable composition", "curable ink", and "ink" are used interchangeably and refer to the curable composition that can be deposited on the surface and cured Composition. Even though the curable composition can be described as an ink, it does not necessarily mean that it has been or needs to be applied by printing techniques. The curable composition generally does not contain a solvent, and has a viscosity of less than 30 centipoise at room temperature to 60°C.

Also revealed are items. In some embodiments, the articles include a substrate having a first major surface and a second major surface, and an optical scattering layer disposed on the first major surface of the substrate. The optical scattering layer includes a matrix and phase-separated microdomains, wherein the matrix and the phase-separated microdomains have different refractive indices, and wherein the microdomains are approximately or greater than the wavelength of visible light.

Also disclosed are methods of making articles. In some embodiments, the method includes providing a substrate having a first major surface and a second major surface; providing a curable composition; A layer of curable composition is formed on at least a portion of the first major surface of the substrate; and the layer of curable composition is cured to form a cured optical scattering layer. The curable composition includes at least one fluoropolymer, at least one monofunctional (meth)acrylate, at least one difunctional (meth)acrylate, and at least one initiator. As mentioned above, the curable composition generally has a viscosity of less than 30 centipoise at a temperature of room temperature to 60°C. The cured optical scattering layer includes a matrix and phase-separated microdomains, wherein the matrix and the phase-separated microdomains have different refractive indices, and wherein the microdomains are approximately or greater than the wavelength of visible light.

10A‧‧‧Base layer

10B‧‧‧Base layer

10C‧‧‧Base layer

10D‧‧‧Substrate layer

10E‧‧‧Base layer

10F‧‧‧Base layer

10G‧‧‧Base layer

10H‧‧‧Base layer

10I‧‧‧Substrate layer

20A‧‧‧curable composition

20B‧‧‧curable composition

20C‧‧‧curable composition

20F‧‧‧curable composition

20G‧‧‧curable composition

20H‧‧‧curable composition

20I‧‧‧curable composition

21D, 22D, 23D‧‧‧curable composition sublayer

21E‧‧‧curable composition sublayer

22E‧‧‧curable composition sublayer/surface sublayer

30A‧‧‧actinic radiation

30D‧‧‧actinic radiation

30E‧‧‧actinic radiation

30F, 30F’‧‧‧actinic radiation/radiation

30G‧‧‧actinic radiation/radiation

30H‧‧‧actinic radiation

30I‧‧‧actinic radiation

31B, 32B, 33B ‧‧‧actinic radiation

31C, 32C, 33C ‧‧‧actinic radiation

40A‧‧‧phase separation microdomain

40F, 41F, 42F‧‧‧‧phase separation microdomain

40G, 41G, 42G‧‧‧phase separated microdomain

40H‧‧‧phase separation microdomain

40I‧‧‧phase separation microdomain

41B, 42B, 43B‧‧‧phase separation microdomain

41C, 42C, 43C‧‧‧phase separation microdomain

41D, 42D, 43D‧‧‧phase separation microdomain

41E, 42E‧‧‧phase separation microdomain

50A‧‧‧cured matrix

50B‧‧‧cured matrix

50C‧‧‧Cure matrix

50D‧‧‧cured matrix

50E‧‧‧cured matrix

50F, 51F ‧‧‧ cured matrix

50G, 51G‧‧‧ cured matrix

50H‧‧‧cured matrix

50I‧‧‧cured matrix

60F‧‧‧Mask

70G‧‧‧actinic radiation/light source/radiation

80H‧‧‧Nano particles

90I‧‧‧Tool film

100‧‧‧Step

110‧‧‧Step

I ₁ , I ₂ , I ₃ ‧‧‧ Intensity

The following implementations of the various embodiments disclosed in the present disclosure can be more fully understood in conjunction with the accompanying drawings.

FIG. 1A shows a schematic diagram of the disclosed process for forming an optical light scattering article.

FIG. 1B shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

1C shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

FIG. 1D shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

FIG. 1E shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

FIG. 1F shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

FIG. 1G shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

FIG. 1H shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

FIG. 11 shows a schematic diagram of another process of the present disclosure for forming an optical light scattering article.

2 shows a cross-sectional view of an optical microscope view of the optical light scattering layer of Example 2. FIG.

3A shows a cross-sectional view of the AFM height image of the optical light scattering layer of Example 2. FIG.

3B shows a cross-sectional view of the AFM-IR map of the optical light scattering layer of Example 2. FIG.

3C shows a cross-sectional view of the AFM-IR mapping of the optical light scattering layer of Example 2. FIG.

3D shows a cross-sectional view of the AFM-IR image ratio mapping of the optical light scattering layer of Example 2. FIG.

4 shows a cross-sectional view of an optical microscope image of the optical light scattering layer of Example 1. FIG.

5A shows a cross-sectional view of the AFM height image of the optical light scattering layer of Example 1. FIG.

5B shows a cross-sectional view of the AFM-IR mapping of the optical light scattering layer of Example 1. FIG.

5C shows a cross-sectional view of the AFM-IR mapping of the optical light scattering layer of Example 1. FIG.

5D shows a cross-sectional view of the AFM-IR image ratio mapping of the optical light scattering layer of Example 1.

In the description of the embodiments shown below, reference is made to the accompanying drawings, which illustrate various embodiments that can implement the present disclosure. It should be understood that these embodiments may be adopted and structural changes may be made without departing from the scope of this disclosure. The drawings are not necessarily drawn to scale. Similar numbers used in the drawings refer to similar components. However, it will be understood that the use of component symbols in a given drawing to refer to a component is not intended to limit the components to the same component symbol in another drawing.

The increased complexity of optical devices makes it more difficult to meet the requirements for the materials used in them. In particular, organic polymeric materials have been found to be widely used in optical devices, but these polymeric materials have increasingly stringent requirements.

For example, for a wide range of applications in optical devices, such as adhesives, protective layers, spacer layers, and the like, thin organic polymer films are desirable. As items become more complex, the physical requirements for these layers have also increased. For example, As optical devices become more sophisticated, and at the same time often include more layers, thinner layers are more needed. At the same time, because the layer is thinner, the layer also needs to be more precise. For example, a thin spacer layer (having a thickness of 1 micrometer) needs to be flat and free of gaps and holes in order to effectively function as a spacer to provide a proper spacer function. This requires the organic layer to be deposited in a precise and consistent manner. One method that has been developed to provide accurate and consistent organic layer deposition is printing technology. In printing technology, a polymer or a curable composition that forms a polymer upon curing is printed onto the surface of a substrate to form a layer. In the case of printable polymers, generally a solvent is added to make the polymer a printable solution or dispersion. When using polymers, after printing to produce the desired polymeric layer, generally a drying step is necessary. In the case of a curable composition that will form a polymer upon curing, the curable composition may or may not include a solvent. The curable composition is then cured, generally using heat or radiation (such as UV light), and the layer can also be dried if a solvent is used. A wide variety of printing techniques can be used, and inkjet printing is particularly desirable because inkjet printing has excellent precision.

In addition, these layers must not only provide their physical roles (adhesion, protection, spacing, and the like), they must also provide the necessary optical properties. An optical property that is becoming increasingly important is light diffusion. In general, light diffusion has been achieved through the use of particles. The light-diffusing particles are dispersed in the polymerizable binder to form a curable mixture, and the curable mixture is placed on the surface and cured to form a layer having the light-diffusing particles suspended in the polymer matrix.

Although this method for preparing a light diffusing layer has been widely used, it has serious disadvantages and limitations. Adding pre-formed particles and fillers may be problematic, not only Because of the complexity of backscattering, and because the addition of such particles and fillers makes the filtration process more difficult, this procedure is usually needed to improve the uniformity of the coating. In addition, as the layer has become thinner and thinner, techniques such as inkjet printing are increasingly used to place the curable layer on the surface, and because the preformed particles tend to clog the printhead nozzle, the Printing to form particle-filled mixtures can be very difficult. In addition, although a uniform diffusion layer can be manufactured in this way, that is, a layer having the same diffusion properties over the entire area of the layer, it is difficult (if possible) to produce a selective diffusion layer in this way. As used herein, a selective diffusion layer refers to a layer with different diffusion properties in different regions of the layer.

Other techniques have been used to provide the scattering layer without using pre-formed particles for optical applications.

Yang et al. (US 2010/0259825) blended two incompatible monomers into an emulsion, applied it, and then cured to lock it in this form. This does not allow control of morphology during curing. Conversely, before curing, morphology control is performed by changing the mixing amount and/or mixing speed before dispensing. Emulsions require stabilizers and other chemical components to maintain stability and control the size of the microdomains formed, which can reduce the possible refractive index difference between the two phases, and therefore reduce the amount of scattering that can be achieved. No control of the size of these phases beyond initial emulsification was shown.

Young et al. (US 9,093,666) also describe a phase separation solution in which two different epoxy polysiloxane monomers are mixed with cycloaliphatic epoxy monomers that do not contain polysiloxane and a photoinitiator. Before curing, one of the epoxy polysiloxane resins used is immiscible with cycloaliphatic epoxy resin, and before curing, stirring is used to achieve different particle size distributions in the range of 0.5 to 20 microns. Apply this layer as an encapsulation layer between two inorganic layers to enhance the OLED Light outcoupling of the device. During the curing step, the control of the degree of phase separation was not demonstrated or discussed.

Mazurek et al. (US 8343633B2) use a radiation-curable telechelic polysiloxane-containing monomer dissolved in a radiation-curable monomer that does not contain silicone. In this method, the two phases are miscible with each other before curing, but the phases separate after curing. During the curing step, it showed some degree of control over the size of the microdomains, although the two phases contained cross-linkable (meth)acrylate moieties, allowing cross-linking between the phases, thereby limiting diffusion and phase separation degree.

Another technique that has been used to prepare light-diffusing pressure-sensitive adhesives without the use of added particles is described in US Patent No. 9,238,762 (Schaffer et al.). In this application, the block copolymer is dissolved in a solvent with an optically clear pressure-sensitive adhesive matrix. After the solvent is dried, the block copolymer is separated from the polymer used for the pressure-sensitive adhesive. The micro-domain formed by the block copolymer is larger than the wavelength of visible light, thus diffusing visible light. During the drying step, control of the degree of phase separation was not discussed or demonstrated, and the distribution of micro-domain size was the same at all points along the layer.

The difference between this disclosure and these is that non-polymerizable amorphous fluoropolymer (generally fluoroelastomer) is dissolved in an organic radiation-curable monomer mixture to form an initial clear, miscible solution . Upon curing, the fluoropolymer phase is separated from the methacrylate phase, providing a change in refractive index that allows adequate optical scattering. Since the polymer will not copolymerize with the monomer during curing, this allows a greater amount of control over the scattering required for adequate phase separation. For example, the ability to control the particle size during the curing step has been demonstrated by changing the light intensity used during curing, thereby affecting the polymerization rate. In addition, it is surprising that the fluoropolymer can be dissolved in (non-fluorine) (meth)acrylate monomer, The two materials have very different chemical structures. The use of such chemically different materials allows for a large difference in refractive index provided by each of the components after phase separation occurs. Finally, the ability to control phase separation during the curing step allows the use of patterning methods well known in the art to produce a variety of different domain sizes within a layer, which may be beneficial in certain applications.

The present disclosure provides a curable composition that does not contain particles and can form a light-diffusing layer. The curable composition includes a fluoropolymer and (meth)acrylate and a radical initiator, and forms a homogeneous single phase before curing. In general, fluoropolymers have good miscibility with (meth)acrylate monomers, and therefore the uncured composition layer does not contain microdomains rich in fluorocarbon compounds. Conversely, fluoropolymer/(methyl ) The acrylate mixture is substantially homogeneous and transparent. The terms fluoropolymer and fluorocarbon are used interchangeably to refer to the fluoropolymer disclosed herein. When the photoinitiator is activated by UV irradiation, free radicals are generated in the film, which induces the polymerization of (meth)acrylate monomers and causes the phase separation of fluoropolymer or poly(meth)acrylate into discrete Domain, this is due to a decrease in entropy and an increase in the free energy of mixing between the two components. Due to the difference in refractive index between the poly(meth)acrylate and the fluoropolymer, the formation of phase-separated microdomains leads to an increase in forward scattering of light (also known as "haze"). When light rays are scattered forward, the light diffuses, but continues in the same general direction of incidence. In backscattering, light is directed back in the direction of incidence. Therefore, in backscattering, some light intensity is lost due to reflection back to the light source. In forward scattering, only a small amount of light is lost due to reflection because most of the light is transmitted along the incident direction, but only diffused. This is desirable when using a point light source, which will produce bright spots and adjacent non-light spots, the light from the point light source exists in the bright spots, and there is no light spot There is no light transmission. By using the forward scattering diffuser, the light from the point light source is spread over a larger area to eliminate the bright spot/no light spot phenomenon. Those of ordinary skill in the art fully understand forward and backscatter.

The light diffusion layer is prepared by disposing the curable composition on the substrate and curing the curable composition to form a cured organic layer having a matrix and phase-separated microdomains, where the matrix and phase-separated microdomains have different The refractive index. This procedure of curing the miscible composition to form a cured composition having phase separation domains is sometimes referred to as PIPS (polymerization-induced phase separation). In the present application, the domain size is large enough to diffuse visible light, in other words, its average diameter is about or greater than the wavelength of visible light (about 400 to 700 nm). The PIPS model means that it may be expected that the matrix will be a cross-linked (meth)acrylate matrix with microdomains of fluoropolymer. Although this does occur, as will be explained in more detail below, the cured organic layer formed is far more complex than a simple crosslinked (meth)acrylate matrix with microdomains of fluoropolymer. It has been found that the cured organic layer contains at least one of three different composition types or composition regions. Each of these regions includes a matrix and phase-separated microdomains. The first zone is a zone in which the substantially continuous matrix contains a cross-linked (meth)acrylate matrix and phase-separated fluorocarbon-rich microdomains, wherein the fluorocarbon-rich microdomains are mainly (if not substantially all) It is a fluorocarbon compound. This embodiment is described above. The second zone is a zone where the substantially continuous matrix contains a cross-linked (meth)acrylate matrix, and the phase-separated microdomains contain (meth)acrylate material and a fluoropolymer. In these embodiments, the microdomain can still be described as a fluoropolymer-rich microdomain, but it includes the fluoropolymer nanodomain and the crosslinked (meth)acrylate nanodomain. The third zone is where the substantially continuous matrix contains fluorocarbon-rich domains and phase-separated microdomains are rich The (meth)acrylate region, in which (meth)acrylate-rich microdomains contain at least cross-linked (meth)acrylate materials, and may also contain fluoropolymers.

The optical scattering layer includes at least one of the above regions. In some embodiments, the optical scattering layer is all one region, and the whole is substantially uniform. In other embodiments, the optical scattering layer contains more than one zone. This phenomenon in different regions is different from the selective diffusion property described below, and refers to the composition of the matrix and phase-separated microdomains.

Another feature of the present disclosure is the ability to use selective curing to create a selective diffusion layer. As used herein, a selective diffusion layer refers to a layer with different diffusion properties in different regions of the layer. This selectivity is described in more detail below and can be implemented in a wide variety of ways, such as by using variable intensity light sources and masking techniques.

Disclosed herein is a curable composition comprising at least one fluoropolymer, at least one monofunctional (meth)acrylate, at least one difunctional (meth)acrylate, and at least one initiator. The curable composition generally has a viscosity of less than 30 centipoise at room temperature to 60°C. This viscosity allows the curable composition to be printed by techniques such as inkjet printing technology, but of course a wide variety of coating techniques can be used to apply the curable composition.

Also disclosed herein is an article containing a cured layer prepared from a curable composition, wherein the cured layer includes a matrix and phase-separated microdomains, wherein the matrix and phase-separated microdomains have different refractive indices, and at least some of the microdomains It is approximately or greater than the wavelength of visible light, and therefore can diffuse visible light. In addition, a method of preparing such articles is described.

Unless otherwise specified, all numbers used to express the size, number and physical characteristics of features in the specification and patent application should be understood as modified by the word "about" in all cases. Therefore, unless otherwise indicated otherwise The numerical parameters proposed in the description and the accompanying patent application are approximate values, which can be different according to the desired characteristics of those skilled in the art using the teachings disclosed herein. The numerical range expressed by the endpoint includes all numbers included in the range (for example, 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within the range.

As used in this specification and the scope of the accompanying patent applications, the singular forms "a" and "the" cover embodiments with plural referents unless the context clearly indicates otherwise. For example, reference to "a layer" covers embodiments with one, two, or more layers. As used in this specification and the accompanying patent application, unless the context clearly indicates otherwise, the term "or (or)" is generally used to include "and/or (and/or)".

As used herein, the term "adjacent" refers to two layers next to another layer. Adjacent layers may be in direct contact with each other, or have an intervening layer. There is no empty space between adjacent floors.

The curable ink composition is "substantially solvent free" or "solvent free". As used herein, "substantially solvent-free" refers to non-polymerizable (eg, organic) solvents having less than 5wt-%, 4wt-%, 3wt-%, 2wt-%, 1wt-%, and 0.5wt-% The curable ink composition. The solvent concentration can be determined by known methods, such as gas chromatography (as described in ASTM D5403). The term "solvent free" means that the solvent is not present in the composition. It should be noted that no matter whether the curable ink composition is substantially solvent-free or solvent-free, no solvent is intentionally added.

Generally speaking, the curable ink composition is described as "100% solids". As used herein, "100% solids" refers to a curable ink composition that does not contain volatile solvents, so that all the mass deposited on the surface remains on the surface, and there is no volatile mass from Coating loss.

As used herein, the term "polymer" refers to a material that is a macromolecule and can be a homopolymer or copolymer. The term "homopolymer" as used herein refers to a polymeric material that is the reaction product of a monomer. The term "copolymer" as used herein refers to a polymeric material that is the reaction product of at least two different monomers.

The terms "Tg" and "glass transition temperature" are used interchangeably. Unless otherwise specified, if measured, the Tg value is determined by differential scanning calorimetry (DSC) at a scan rate of 10°C/min. Generally speaking, the Tg value of the copolymer is not measured, but is calculated using the well-known Fox equation, and the calculation uses the monomer Tg value provided by the monomer supplier, as those with ordinary knowledge in the technical field understanding.

The terms "room temperature" and "ambient temperature" are used interchangeably and have their conventional meaning, which refers to a temperature of 20 to 25°C.

As used herein, the term "organic" is used to refer to a cured layer, meaning that the layer is prepared from organic materials and contains no inorganic materials.

The terms "fluoropolymer" or "fluorinated polymer" are used interchangeably and refer to fluorine-based Carbon compound polymer. Fluoropolymers are hydrocarbon polymers in which hydrogen atoms (generally many hydrogen atoms, or even all hydrogen atoms) have been replaced by fluorine atoms. An example of a fluoropolymer is "fluoroelastomer". The fluoroelastomer system does not contain a large amount of crystallinity for special-purpose fluorocarbon-based synthetic rubber.

The term "(meth)acrylate" refers to the monomeric acrylate or methacrylate of alcohol. Acrylate and methacrylate monomers or oligomers are collectively referred to herein as "(meth)acrylates". As used herein, the term "(meth)acrylate-based" refers to a polymeric composition that includes at least one (meth)acrylate monomer and may include additional (meth) Acrylate or non-(meth)acrylate copolymerizable ethylenically unsaturated monomer. The (meth)acrylate-based polymer mainly contains (that is, greater than 50% by weight) (meth)acrylate monomers.

The terms "free radically polymerizable" and "ethylenically unsaturated" are used interchangeably and refer to a reactive group containing a carbon-carbon double bond that can be polymerized via a radical polymerization mechanism.

The term "hydrocarbon group" as used herein refers to any monovalent group that contains mainly or only carbon and hydrogen atoms. Alkyl and aryl groups are examples of hydrocarbon groups.

The term "alkyl" refers to a monovalent group of an alkane radical, which is a saturated hydrocarbon. The alkyl group may be linear, branched, cyclic, or a combination thereof, and generally has 1 to 20 carbon atoms. In some embodiments, the alkyl group contains 1 to 18, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. Examples of alkyl groups include but are not limited to Group, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tertiary butyl, n-pentyl, n-hexyl, cyclohexyl, n-heptyl, n-octyl, and ethylhexyl.

The term "aryl" refers to a monovalent group that is aromatic and carbocyclic. The aryl group may have one to five rings connected to or fused to the aromatic ring. The other ring structure may be an aromatic ring, a non-aromatic ring, or a combination thereof. Examples of aryl groups include, but are not limited to, phenyl, biphenyl, triphenyl, anthracenyl, naphthyl, acenaphthyl, anthraquinonyl, phenanthrenyl, anthracenyl, pyrenyl, perylene , And Fu Ji.

The term "alkylene" refers to a divalent radical of an alkane radical. The alkylene group may be linear, branched, cyclic, or a combination thereof. The alkylene group often has 1 to 20 carbon atoms. In some embodiments, the alkylene group contains 1 to 18, 1 to 12, 1 to 10, 1 to 8, 1 to 6, or 1 to 4 carbon atoms. The center of the alkylene group can be on the same carbon atom (ie, alkylene) or on a different carbon atom.

The term "heteroalkylene" refers to a divalent group including at least two alkylene groups connected by a thio group, an oxy group, or -NR-, wherein R is an alkyl group. The heteroalkylene group may be linear, branched, cyclic, substituted with an alkyl group, or a combination thereof. Some heteroalkylene groups are polyoxyalkylene groups in which the heteroatom is oxygen, such as, for example, —CH ₂ CH ₂ (OCH ₂ CH ₂ ) _n OCH ₂ CH ₂ —.

As used herein, the term "alicyclic" refers to a group having both aliphatic and cyclic properties, which contains one or more fully carbocyclic rings that may be saturated or unsaturated, but does not have aromatic Characteristics, and can be substituted by one or more alkyl groups.

Unless otherwise specified, "optically transparent" means having a high light transmittance in at least a portion of the visible spectrum (about 400 to about 700 nm) Layers, films, or articles. Generally speaking, an optically transparent layer, film, or article has a light transmittance of at least 90%.

Unless otherwise specified, the term "optically clear" refers to a layer, film, or article that has a high light transmittance in at least a portion of the visible light spectrum (about 400 to about 700 nm) and exhibits low fog degree. Generally speaking, the optical clear layer, film, or article has a visible light transmittance value of at least 90%, usually at least 95%, and a haze value of 5% or less, usually 2% or less. Light transmittance and haze can be measured using the techniques described in the "Examples" section.

This article discloses curable compositions, articles made using these curable compositions, and methods of making articles using these curable compositions. The curable composition disclosed herein provides a method for selectively preparing an optical scattering layer. Optical scattering means that the layer forward scatters visible light. As mentioned above, the optical scattering layer acts as a layer that diffuses visible light. The diffusion system in which visible light occurs is that the curable composition forms phase-separated microdomains in the matrix during curing, and the matrix and phase-separated microdomains have different refractive indexes. In the present disclosure, the phase-separated microdomain is approximately equal to or greater than the wavelength of visible light. Since visible light is usually characterized as having a wavelength of 400 to 700 nanometers, the phase-separated microdomain is usually at least 100 nm or larger, often 100 to 4,000 nm. Microdomain "fluoropolymer-rich" means that it has a high concentration of fluoropolymer in the (meth)acrylate matrix, but it does not necessarily consist entirely of fluoropolymer; or "rich "(Meth)acrylate-rich" means that it has a high concentration of (meth)acrylate in a fluoropolymer-rich matrix, but it is not necessarily entirely composed of (meth)acrylate Acrylic composition. The presence of a microdomain with a different refractive index from the surrounding matrix means that when visible light passing through the matrix encounters the microdomain, the visible light will The refractive index is mismatched and refracted or scattered, as described in Snell’s Law. This scattering is often referred to as forward scattering or haze. As mentioned above, forward scattering is desirable because it causes very little loss of light intensity of diffuse light.

In the present disclosure, a curable composition is provided, which contains a fluoropolymer and a curable (meth)acrylate monomer. These curable compositions are optically transparent or even optically clear because of the high miscibility of fluoropolymers with (meth)acrylate monomers. The curable composition also has a relatively low viscosity, allowing it to be applied by various methods including inkjet printing. Once the curable composition is cured, the curable composition forms a cured organic layer having a matrix and phase-separated microdomains, wherein the matrix and phase-separated microdomains have different refractive indices, and at least some of the phase-separated microdomains are approximately Or greater than the wavelength of visible light (400 to 700nm). In some embodiments, the phase-separated microdomains are in the range of 100 to 4,000 nm. This article also discloses a method for preparing an article having an optical scattering layer.

This article discloses curable compositions. The curable composition includes at least one fluoropolymer, at least one monofunctional (meth)acrylate, at least one difunctional (meth)acrylate, and at least one initiator. The curable composition generally has a viscosity of less than 30 centipoise at room temperature to 60°C. In general, the curable composition contains no solvent. In many embodiments, the curable composition is optically transparent or even optically clear. One advantage of these relatively low viscosity compositions is that they are inkjet printable. Inkjet printable means that the composition can be inkjet printed and does not mean that the composition must be inkjet printed or the composition has been inkjet printed. In this way, the inkjet printable expression is a compositional limit of the curable composition, and is not a program limit. The inkjet printable material can be applied in various ways.

The curable composition includes at least one fluoropolymer. Fluoropolymers are fluorocarbon-based polymers with multiple carbon-fluorine bonds. It is characterized by high resistance to solvents, acids, and alkalis. Fluoropolymers are hydrocarbon polymers in which hydrogen atoms (generally many hydrogen atoms, or even all hydrogen atoms) have been replaced by fluorine atoms.

Fluoropolymers share the properties of fluorocarbons, and unlike hydrocarbons, they are susceptible to van der Waals forces. Therefore, similar to fluorocarbon compounds, fluoropolymers are very stable due to the strength of carbon-fluorine bonds, one of the strongest in organic chemistry of carbon-fluorine bonds. Its strength is the result of the electronegative nature of fluorine, which imparts partial ionic properties through the partial charge on the carbon and fluorine atoms, which shortens and strengthens the bond through favorable covalent interactions. In addition, multiple carbon-fluorine bonds increase the strength and stability of other adjacent carbon-fluorine bonds on the same geminal carbon because the carbon has a higher positive partial charge. Furthermore, multiple carbon-fluorine bonds also strengthen the "skeletal" carbon-carbon bond from the induced effect. Therefore, saturated fluorocarbon compounds have better chemical and thermal stability than their corresponding hydrocarbon counterparts and virtually any other organic compounds. It is generally not miscible with most organic solvents (eg, ethanol, acetone, ethyl acetate, and chloroform), but is miscible with some hydrocarbons (eg, hexane in some cases). It has a low refractive index generally less than 1.45.

The curable composition of the present disclosure includes at least one fluoropolymer, based on 100% by weight of the total curable composition, the at least one fluoropolymer accounts for 1 to 20% by weight. Examples of suitable fluoropolymers are amorphous fluoropolymers containing 60 to 70% fluorine content. The fluorine content means that 60 to 70% of the replaceable hydrogen atoms have been replaced by fluorine groups. A particularly suitable class of fluoropolymers are fluoroelastomers. Fluoroelastic systems are amorphous and do not contain a large amount of crystallinity. They are special-purpose fluorocarbon-based synthetic rubbers. It has a wide range of chemical resistance and excellent Different performance, especially in high temperature applications in different media. Fluoroelastic systems are classified as FKM according to ASTM D1418 and ISO 1629 designations. This type of elastic system includes the copolymerization of hexafluoropropylene (HFP) and difluoroethylene (VDF or VF2), tetrafluoroethylene (TFE), difluoroethylene (VDF), and hexafluoropropylene (HFP). Products, and a family of perfluoromethyl vinyl ethers (PMVE) containing specialty chemicals. Particularly suitable copolymers of fluoroelastomer systems difluoroethylene (VDF) and hexafluoropropylene (HFP), such as materials commercially available from 3M Company, St. Paul, MN, FC 2145, FC 2178, and FC 2211.

As mentioned above, fluoropolymers generally have low miscibility with organic solvents and fluids. In the present disclosure, it has been observed that in the curable composition, the fluoropolymer has high miscibility with the (meth)acrylate monomer containing a cyclic portion. In fact, in many embodiments, the curable composition is optically clear. Other fluoropolymer systems that can be used are described in Jing et al. (US 2006/0147177 A1).

A desirable feature of fluoropolymer is that it has a different refractive index from the (meth)acrylate matrix, which is obtained by the polymerization of (meth)acrylate monomers described below form. Fluoropolymers generally have a refractive index in the range of 1.40 to 1.41. This refractive index is different from the refractive index of the (meth)acrylate matrix generally in the range of 1.48 to 1.50.

The curable composition also includes at least one monofunctional (meth)acrylate. A wide range of monofunctional (meth)acrylates are suitable. In some embodiments, the monofunctional (meth)acrylate comprises monofunctional methacrylate. In some embodiments, methacrylate is more desirable than acrylate, because methacrylate polymerizes more slowly, allowing a more controlled reaction rate, and thus has more control over the diffusion properties of the resulting film . Examples include but are not limited to acrylamides, such as acrylamide, methacrylamide, N-methacrylamide, N-ethylacrylamide, N-hydroxyethylacrylamide, diacetone acrylamide Amine, N,N-dimethylacrylamide, N,N-diethylacrylamide, N-ethyl-N-amine ethylacrylamide, N-ethyl-N-hydroxyethylacrylamide Amine, N,N-dihydroxyethyl acrylamide, tertiary butyl acrylamide, N,N-dimethylamine ethyl acrylamide, and N-octyl acrylamide. Examples of suitable monofunctional (meth)acrylates include cycloaliphatic methacrylates. The alicyclic compound is an organic compound having both aliphatic and cyclic properties. They contain one or more full carbon rings that can be saturated or unsaturated, but do not have aromatic characteristics. The alicyclic compound may have one or more attached aliphatic side chains. In some embodiments, alicyclic compounds may include one or more heteroatoms. Monocyclic cycloalkanes and cycloolefins include cyclopentane, cyclopentene, cyclohexane, cyclohexene, cycloheptane, cycloheptene, cyclooctane, cyclooctene, and the like. Bicycloalkanes and alkenes include norbornane, norbornene, and norbornadiene. Examples of suitable alicyclic (meth)acrylates include 3,3,5-trimethylcyclohexyl acrylate and methacrylate, 1-adamantyl acrylate and methacrylate, 3,5- Dimethyladamantyl acrylate and methacrylate, and isobornyl acrylate and methacrylate. Examples of heteroatom-functional cycloaliphatic (meth)acrylates include methyl tetrahydrofuran acrylate and methyl tetrahydrofuran methacrylate. The monofunctional (meth)acrylate can be present in a wide range of amounts. In some embodiments, the monofunctional (meth)acrylate contains 60 to 95 parts by weight based on the total weight of the curable components of the curable composition.

It is also possible to use monomers containing unsaturation in the form of vinyl groups. These are well known in the art to perform chemical reactions and crosslink into (meth)acrylate matrices. Preferred examples of vinyl-containing monomers (which also include cyclic moieties) include n-vinyl Pyrrolidone and n-vinylcaprolactam. A suitable range of the vinyl-containing monomer includes 1 to 20 parts by weight based on the total weight of the curable components of the curable composition.

The curable composition also includes at least one multifunctional (meth)acrylate. In some embodiments, the multifunctional (meth)acrylate comprises a bifunctional (meth)acrylate. In some embodiments, the bifunctional (meth)acrylate comprises bifunctional methacrylate. Again, as with monofunctional (meth)acrylates, bifunctional methacrylates can be particularly suitable because they polymerize more slowly than the corresponding acrylates, allowing more control over the polymerization rate. Examples of suitable bifunctional (meth)acrylates include aliphatic (meth)acrylates of general formula I:

H ₂ C=CR2-(CO)-OAO-(CO)-R2C=CH ₂ Formula I where R2 is hydrogen or methyl, (CO) is carbonyl C=O, and A contains alkylene or heteroalkylene Divalent group. Examples of the alkylene group include those having 4 to 20 carbon atoms, and may include cyclic groups. Examples of heteroalkylene groups include polyoxyethylene groups, polyoxypropylene groups, and the like. Examples of useful polyfunctional (meth)acrylates include, but are not limited to, 1,6-hexanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, propylene glycol di(meth)acrylate Base) acrylate, ethylene glycol di(meth)acrylate, hydroxytrimethylacetate neopentyl glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, bisphenol A di( Methacrylate, tricyclodecane dimethanol di(meth)acrylate, poly(ethylene glycol) di(meth)acrylate, polybutadiene di(meth)acrylate, polycarbamic acid Ester di(meth)acrylate, glycerol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ginseng (2-hydroxyethyl) isocyanurate triacrylate, neopentyl Tetraol tri(meth)acrylate, neopentyl tetraol (meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, di Neopentaerythritol hexa(meth)acrylate, as well as ethoxylated and propoxylated versions, and mixtures thereof.

The multifunctional (meth)acrylate or crosslinking agent can be present in a wide range of amounts. In some embodiments, the multifunctional (meth)acrylate accounts for 1 to 20 parts by weight based on the total weight of the curable components of the curable composition. The amount and characteristics of the cross-linking agent or cross-linking agents may vary, but generally the total amount of cross-linking agent is present in an amount of at least 5% by weight. The wt% refers to the wt% of all curable components of the curable ink composition.

The curable composition also contains at least one initiator. In general, the initiator is a photo-initiator, which means that the initiator is activated by light (generally ultraviolet (UV) light). The photoinitiator is well understood by those having ordinary knowledge in the technical field of (meth)acrylate polymerization.

Useful photoinitiators include those known to be useful for free radical photocuring of multifunctional (meth)acrylates. Exemplary photoinitiators include benzoin and its derivatives, such as α-methyl benzoin; α-phenyl benzoin; α-allyl benzoin; α-benzyl benzoin; benzoin ethers, such as benzophenone dimethyl Ketals (for example, "OMNIRAD BDK" from IGM Resins USA Inc., St. Charles, IL), benzoin methyl ether, benzoin ethyl ether, benzoin n-butyl ether; acetophenone and its derivatives, such as 2 -Hydroxy-2-methyl-1-phenyl-1-acetone (e.g. available from IGM Resins USA Inc., St. Charles, IL under the trade name OMNIRAD 1173) and 1-hydroxycyclohexyl phenyl ketone (e.g. a trademark) The name OMNIRAD 184 was purchased from IGM Resins USA Inc., St. Charles, II); 2-methyl -1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-acetone (for example, it can be purchased from IGM Resins USA Inc., St. Charles, IL under the trade name OMNIRAD 907); 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone (for example, it can be purchased from IGM Resins USA Inc. under the trade name OMNIRAD 369 St. Charles, IL); and phosphine oxide derivatives, such as ethyl-2,4,6-trimethylbenzylphenylphosphinate (for example, available from IGM Resins USA Inc under the trade name TPO-L ., St. Charles, IL) and bis(2,4,6-trimethylbenzyl)-phenylphosphine oxide (e.g. available from IGM Resins USA Inc., St. Charles, IL under the trade name OMNIRAD 819 ).

類、二苯基酮及其衍生物、錪鎓鹽類及鋶鹽類、鈦錯合物(諸如雙(η-2,4-環戊二烯-1-基)-雙[2,6-二氟-3-(1H-吡咯-1-基)苯基]鈦，例如可以商標名稱CGI 784DC購自BASF,Florham Park,NJ)；鹵甲基硝基苯類(例如4-溴甲基硝基苯)、及光起始劑的組合，其中一個組分係單-或雙-醯基膦氧化物(例如可以商標名稱IRGACURE 1700、IRGACURE 1800、及IRGACURE 1850購自BASF,Florham Park,NJ、以及以商標名稱OMNIRAD 4265購自IGM Resins USA Inc.,St.Charles,IL)。 Other useful photoinitiators include, for example, pivaloin ethyl ether, anisoin ethyl ether, anthraquinones (e.g. anthraquinone, 2-ethylanthraquinone, 1-chloroanthraquinone, 1,4-dimethylanthraquinone, 1-methoxyanthraquinone, or benzanthraquinone (benzanthraquinone), halomethyl tri

, Diphenyl ketone and its derivatives, phosphonium salts and osmium salts, titanium complexes (such as bis(η-2,4-cyclopentadien-1-yl)-bis[2,6- Difluoro-3-(1H-pyrrol-1-yl)phenyl] titanium, available for example under the trade name CGI 784DC from BASF, Florham Park, NJ); halomethylnitrobenzenes (eg 4-bromomethylnitrate Benzene), and a combination of photoinitiators, one of which is a mono- or bis-acylphosphine oxide (for example, under the trade names IRGACURE 1700, IRGACURE 1800, and IRGACURE 1850 from BASF, Florham Park, NJ, And purchased from IGM Resins USA Inc., St. Charles, IL under the trade name OMNIRAD 4265).

Generally, the photoinitiator is used in an amount of 0.01 to 5 parts by weight, more generally 0.1 to 0.5 parts by weight, relative to 100 parts by weight of the total reactive components.

The curable composition may include additional optional additives. Optional additives can be reactive or non-reactive. The higher refractive index difference (△n) between the minority and majority phases will increase the haze and scattering power of the film. This will enable the use of less fluoropolymer to achieve the same optical effect as a larger amount of fluoropolymer with a smaller (Δn). Less fluoropolymer will make the viscosity of the ink formulation lower, which will also benefit inkjet performance. Metal oxide nanoparticles will be particularly useful for increasing the refractive index of the poly(meth)acrylate matrix phase.

A wide range of metal oxide nanoparticles are suitable, but as described above, since it is desired to increase the refractive index of the curable ink composition, metal oxide nanoparticles having a high refractive index are desirable. Examples of suitable metal oxide nanoparticles include metal oxides of titanium, aluminum, hafnium, zinc, tin, cerium, yttrium, indium, antimony, and zirconium, and mixed metal oxides, such as, for example, indium tin oxide. In this context, high refractive index refers to a refractive index of 2.0 or higher. More desirable metal oxide nanoparticles are metal oxide nanoparticles of titanium, aluminum, and zirconium. Nanoparticles of titanium oxide, often referred to as titanium dioxide nanoparticles, are particularly suitable because of their high refractive index. In many cases, a single type of metal oxide nanoparticles is used, but a mixture of metal oxide nanoparticles can also be used.

As mentioned earlier, the size of such particles is selected to avoid significant visible light scattering. The surface-treated metal oxide nanoparticles may be (eg, unassociated) particles with a primary particle size or an associated particle size greater than 1 nm, 5 nm, or 10 nm. The primary or associated particle size is usually less than 100 nm, 75 nm, or 50 nm. Generally speaking, the primary or associated particle size is less than 40 nm, 30 nm, or 20 nm. The desire is that the nanoparticles are unassociated and remain unassociated over time. The equivalent measurement can be based on a transmission electron microscope (transmission electron microscopy, TEM) or dynamic light scattering (dynamic light scattering, DLS).

The zirconia and titania nanoparticles may have a particle size of 5 to 50 nm, or 5 to 15 nm, or 8 nm to 12 nm. Suitable zirconia (zirconium dioxide nanoparticles) is available from Nalco Chemical Co. under the trade name "Nalco OOSSOO8" and from Buhler AG Uzwil, Switzerland under the trade name "Buhler zirconia Z-WO sol". Nanoparticles of titanium dioxide (nanoparticles of titanium dioxide) are particularly suitable. Titanium dioxide nanoparticles containing a mixture of anatase and brookite crystal structures are commercially available as "NTB-1" from Showa Denko Corp., Japan.

Nanoparticles are preferably surface treated to improve compatibility with organic matrix materials, and to keep the nanoparticles non-associative, non-cohesive, or combinations thereof in the curable ink composition. The surface treatment for producing surface-treated nanoparticles is a silane surface treatment agent containing at least two silane-functional surface treatment agents.

Another particularly suitable optional additive is an adhesion promoter. Adhesion promoters are used as additives or primers to promote the adhesion of coatings, inks, or adhesives to the substrate of interest. Adhesion promoters usually have an affinity for the substrate and the applied coating, ink, or adhesive. Suitable adhesion promoters are silane-functional compounds, titanates, and zirconates. Examples of suitable titanates and zirconates include titanium butyrate or zirconium butyrate. In general, if used, adhesion promoters contain silane-functional compounds. Sometimes silane-functional adhesion promoters are called coupling agents, because they have different functionalities at each end of the compound, so they can play the role of coupling different surfaces (such as inorganic surfaces and organic surfaces). A wide range of silane adhesion promoters are suitable, such as (meth)acrylate from Momentive Performance Materials Can alkoxy silane SILQUEST A-174. With this type of adhesion promoter, alkoxysilane functionality will interact with the inorganic surface, and (meth)acrylate functionality will copolymerize with the curable ink composition. Other examples of suitable silane coupling agents include octadecyltrimethoxysilane, isooctyltrimethoxysilane, hexadecyltrimethoxysilane, hexyltrimethoxysilane, methyltrimethoxysilane, hexamethyldimethoxysilane Silazane, hexamethyldisilazane, aminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, 3-propenyloxypropylene Trimethoxysilane, and the like.

Useful additives may include polymers containing functional groups known in the art, such as epoxy groups, allyloxy groups, (meth)acrylate groups, (meth)acrylamide groups, epoxides, Episulfide, vinyl, hydroxyl, cyanoester, acetoxy, thiol, silanol, carboxylic acid, amine, phenol, aldehyde, alkyl halide, cinnamic acid ester, azide, aziridine, Olefin, urethane, amide imine, amide, alkyne, ethylenically unsaturated group, vinyl ether group, and any derivatives and any combination thereof. Alternatively, the polymer additive may be non-reactive, such as poly(methyl methacrylate), poly(vinyl butyral), poly(acrylic acid), poly(vinyl alcohol), and others may be used. These polymers may also include copolymers, that is, the polymer is made from more than one type of monomer unit during polymerization. Copolymers can contain different architectures, such as linear, star, graft, random, or block copolymers.

Other optional additives include heat stabilizers, ultraviolet light stabilizers, free radical scavengers, chain transfer agents, photosensitizers, and combinations thereof. Examples of suitable commercially available ultraviolet light stabilizers include diphenyl ketone type ultraviolet absorbers, which can be purchased from BASF Corp., Parsippany, NJ under the trade name "UVINOL 400"; and under the trade names "TINUVIN 900" and "TINUVIN 1130 ”Purchased from BASF, Tarrytown, NY. Relative to polymerizable The total weight of the combined precursors, examples of suitable concentrations of ultraviolet light stabilizers in the polymerizable precursor range from about 0.1wt.% to about 10wt.%, particularly suitable total concentration range from about 1wt.% to about 5wt. %.

Examples of suitable free radical scavengers include hindered amine light stabilizer (HALS) compounds, hydroxylamines, stereo hindered phenols, and combinations thereof. Examples of suitable commercially available HALS compounds include those sold by BASF under the trade names "TINUVIN 123" and "TINUVIN 292". An example range of suitable concentrations of free radical scavenger in the polymerizable precursor ranges from about 0.05 wt.% to about 0.25 wt.% of the precursor solution.

Articles are also revealed in this article. The article includes a substrate having a first major surface and a second major surface; and an optical scattering layer on the first major surface of the substrate, wherein the optical scattering layer. The optical scattering layer scatters visible light. The optical scattering layer is prepared by curing the above curable composition. The optical scattering layer is described in more detail below.

A wide range of substrates are suitable for the items disclosed. The substrate included in the article may contain a polymeric material, a glass material, a ceramic material, a metal-containing material (such as a metal or metal oxide), or a combination thereof. The substrate may include multiple layers of materials, such as support layers, primer layers, hard coats, decorative designs, and the like. The substrate can be permanently or temporarily attached to the adhesive layer. For example, the release liner may be temporarily attached and then removed to attach the adhesive layer to another substrate.

The substrate may have various functions, such as, for example, providing flexibility, encapsulation, barriers, rigidity, strength or support, reflectivity, anti-reflection, polarization, or transmissivity (eg, selective for different wavelengths). That is, the base material can be flexible or rigid; Radiant or non-reflective; visually clear, color but transmissive, graphical (ie with printed images or markings), or opaque (eg non-transmissive); and polarized or non-reflective Polarized.

Exemplary substrates include, but are not limited to, external surfaces of electronic displays (such as liquid crystal, inorganic (LED), or organic light-emitting diode (OLED) displays), external surfaces of windows or glazing, optical components (such as reflective The outer surface of the polarizer, polarizer, diffraction grating, mirror, or lens), another film (such as a graphic or decorative film or another optical film), or the like.

Representative examples of polymeric substrates include polycarbonates, polyesters (e.g. polyethylene terephthalate and polyethylene naphthalate), polyurethanes, poly(meth)acrylates (e.g. (Polymethyl methacrylate), polyvinyl alcohol, polyolefins (such as polyethylene and polypropylene), polyvinyl chloride, polyimide, cellulose triacetate, acrylonitrile-butadiene-styrene copolymer, and Similar to the polymeric substrate.

The substrate may also include an inorganic layer. The inorganic layer may be prepared from various materials, including metals, metal oxides, metal nitrides, metal oxynitrides, metal carbides, metal boron oxides, and combinations thereof. A wide range of metals are suitable for metal oxides, metal nitrides, and metal oxynitrides. Particularly suitable metals include Al, Zr, Si, Zn, Sn, and Ti. A particularly suitable material for the inorganic barrier layer is silicon nitride. In some embodiments, the inorganic layer provides encapsulation and barrier functions to prevent water and oxygen from entering the display device.

The disclosed items can be included in larger items and devices. In some embodiments, a substrate with a light-scattering coating can be incorporated into a display device.

The article of the present disclosure includes an optical scattering layer. The optical scattering layer is prepared by curing the above curable composition. The cured optical scattering layer contains a matrix with microdomains of material, which is different from the material of the matrix. The composition of the matrix and microdomains has been found to be more complicated than expected by the PIPS (polymerization induced phase separation) model. In the PIPS model, it is expected that curable compositions (including fluoropolymers and (meth)acrylate monomers that are miscible with each other, and therefore optically clear fluids) will form in cross-linked (meth)acrylic acid once cured The microdomains of the fluoropolymer in the ester matrix. Although this does occur during curing, the composition of the resulting matrix and microdomains is much more complex.

The optical scattering layer has at least one of three different types of regions. Each of these regions includes a matrix and phase-separated microdomains, where the matrix and phase-separated microdomains have different refractive indices, and wherein the microdomains are approximately or greater than the wavelength of visible light. Generally speaking, the wavelength of visible light is in the range of 400 to 700 nm. Generally, the average diameter of the phase-separated microdomain is 100 to 4,000 nanometers, or 400 to 2,000 nanometers, or 400 to 1,000 nanometers, or even 400 to 700 nanometers. The first type of zone is a zone in which the substantially continuous matrix contains a cross-linked (meth)acrylate matrix and phase-separated fluorocarbon-rich microdomains. The second type of zone is a zone in which a substantially continuous matrix contains a cross-linked (meth)acrylate matrix and the phase-separated microdomains contain a (meth)acrylate material and a fluoropolymer. In these embodiments, the microdomain can still be described as a fluoropolymer-rich microdomain, but it includes the fluoropolymer nanodomain and the crosslinked (meth)acrylate nanodomain. The third type is a region in which the substantially continuous matrix contains fluorocarbon-rich domains and phase-separated (meth)acrylate-rich microdomains, wherein the (meth)acrylate-rich microdomains contain at least Cross-linked (meth)acrylate materials, and may also contain fluoropolymers.

The optical scattering layer includes at least one of the aforementioned types of regions. In some embodiments, the optical scattering layer includes only one type of region, and the entire system is substantially uniform. In other embodiments, the optical scattering layer contains more than one type of region.

In some embodiments, the optical scattering layer includes a cured cross-linked (meth)acrylate matrix with microdomains rich in fluoropolymer. In some embodiments, the fluoropolymer-rich microdomains contain substantially all fluoropolymer (type 1 zone). In other embodiments, the fluoropolymer-rich microdomains include (meth)acrylate material and fluoropolymer (type 2 region). In these embodiments, the fluoropolymer-rich microdomains include fluoropolymer nanodomains and crosslinked (meth)acrylate nanodomains. In some embodiments, the optical scattering layer may include a type 1 region and a type 2 region.

In still other embodiments, the cured light scattering layer includes a region (type 3 region) in which the substantially continuous matrix is rich in fluorocarbon compounds and the phase-separated microdomains are rich in (meth)acrylate. Generally speaking, when there is a third type area, there is also a first type area, a second type area, or a combination of the first type area and the second type area. Since the fluorocarbon compound exists as a secondary component (less than 50% by weight) of the curable composition, there is not enough fluorocarbon compound to form a continuous domain throughout the cured organic layer, but the type 3 region exists in In the localized area of the cured light scattering layer.

As mentioned above, it is not expected to produce three different types of regions in the cured light scattering layer. The PIPS model proposes a relatively simple procedure for forming a cured light scattering layer from a curable composition containing a fluorocarbon compound and (meth)acrylate material. Surprisingly, the fluorocarbon polymer and the (meth)acrylate single system are miscible, because the fluorocarbon polymer and the (meth)acrylate polymer are usually incompatible with each other. compatible. However, since the two materials are miscible with each other before forming the cross-linked poly(methacrylate) matrix, but the fluoropolymer is not miscible with the cross-linked poly(methacrylate) matrix, it is presumed that by polymerization When the (meth)acrylate matrix is formed, fluoropolymer domains are formed. It is desirable to control the size of these domains so that they are micro-domains with an average diameter of 100 to 4,000 nanometers, or 400 to 2,000 nanometers, or 400 to 1,000 nanometers, or even 400 to 700 nanometers. As mentioned above, the cured optical scattering layer is much more complicated than that proposed by the PIPS model.

It has been shown that the cured optical scattering layer (whether it contains only one type area or contains more than one type area) is an optical scattering layer. The optical scattering layer can forward-scatter visible light as needed, as evidenced by the fact that the cured light-scattering layer has a haze value of 5% or higher when measured as described in the “Examples” section.

A relatively new technique combining Atomic Force Microscopy (AFM) and Infrared Spectroscopy (IR) is used to detect the complexity of the cured optical scattering layer, ie the presence of up to three different types of regions within the layer. This new technology is abbreviated as AFM-IR. AFM-IR (technology based on photothermal induced resonance effect (PTIR)) is a combination of atomic force microscopy (AFM) and infrared spectroscopy (IR) for nanoscale characterization. At the same time, it provides the morphology and chemical information of the second 50nm features. AFM-IR technology uses a sharp, gold-coated AFM tip to detect rapid thermal expansion of the sample caused by short (10 nanosecond) pulses absorbing IR radiation. When monochromatic laser radiation approaches the IR frequency that excites molecular vibrations in the sample, the light is absorbed and induces rapid thermal expansion of the sample in contact with the AFM needle tip. This causes the tip of the AFM to flex at the same time, and causes the cantilever to "ring down" at its natural flex resonance frequency when the heat dissipates. Cantilever The motion is "detected" by the second laser beam reflected from the top of the cantilever, and this signal is measured using a position sensitive light detector. The resonance amplitude induced in the cantilever is proportional to the amount of IR radiation absorbed by the sample. Therefore, when tuning the IR laser on the IR fingerprint area, the AFM-IR spectrum is generated by measuring the ringing amplitude. In addition, the IR laser can be fine-tuned to a fixed wavenumber, so that when the AFM tip scans the sample, it can measure the IR absorption that varies with the position. Therefore, a chemical composition map is generated, which shows the distribution of the chemical composition of the entire sample.

This article also discloses a method of preparing articles. In some embodiments, the method includes providing a substrate having a first major surface and a second major surface; providing a curable composition; forming a layer of curable composition on at least a portion of the first major surface of the substrate And curing the layer curable composition to form a cured cross-linked optical scattering layer. The curable composition has been described above and contains at least one fluoropolymer, at least one monofunctional (meth)acrylate, at least one difunctional (meth)acrylate, and at least one initiator, wherein the curable composition It generally has a viscosity of less than 30 centipoise at room temperature to 60°C. The cured cross-linked layer includes a (meth)acrylate matrix and fluoropolymer-rich microdomains, where the microdomains are approximately or greater than the wavelength of visible light. Typically, the microdomain is in the range of 100 to 4,000 nanometers, in some embodiments, in the range of 400 to 2,000 nanometers, 400 to 1,000 nanometers, or even 400 to 700 nanometers.

The formation of the layer of the curable composition can be performed by a wide variety of coating, printing, or other patterning techniques. The printing technique is particularly suitable because these techniques provide excellent control of the layer formation. Examples of suitable printing techniques include screen printing, inkjet printing, flexographic printing, gravure printing, lithographic printing, needle dispensing, and patch coating. In some embodiments, the curable composition is Inkjet printing to apply. In general, the formed layer has a thickness of 1 to 76 microns, and in some embodiments, a thickness of 1 to 51 microns, or even 1 to 25 microns.

The curing of the curable composition is performed by activating the initiator present in the curable composition to initiate free radical polymerization. In general, initiators are photoinitiators that are usually activated by UV or visible light. UV light can be supplied through a variety of different sources, such as lamps. The radiation source used for curing can be "internal" (for example, if the coating is applied to a display, the display sub-pixel itself can be used for curing) or external (laser, a row of UV black light bulbs, UV-LED lights, etc.). If an internal light source is used, red, green, or blue photosensitizers can be added to the resin along with standard free radical initiators. A series of red, green, or blue flashes on the display can be used to cure the ink above each sub-pixel, assuming that the absorbance of the visible light photosensitizer does not overlap. The flashes of each color may have different intensities corresponding to the required curing speed of each sub-pixel scattering layer. A blanket UV flood exposure can be used to complete the curing of the coating area not directly above the sub-pixel.

If you use an external light source, you can use raster scanning, direct writing laser, or UV light source full-face exposure technology with a photomask. If a laser is used for patterning, the laser can have different wavelengths or intensities as needed to create a scattering layer. A laser can be used to illuminate the film at an angle to create a cone of scattering particles within the film instead of a cylinder of scattering particles. In the whole-surface exposure of the UV source, three different masks can be used, where each mask contains opening windows corresponding to the positions of the red, green, or blue sub-pixels, respectively. Perhaps the same fine metal mask used for the evaporation of three different emitting dyes in OLED displays can also be used as a mask for phase-separated inks. Then, different radiation intensities can be used for each exposure as needed.

The curing can be performed in selective subsections of the layer, or the entire layer can be cured. In some embodiments, curing includes pattern-wise curing selected areas of the layer such that the layer contains a series of microdomains. This pattern curing can be performed by selective irradiation or through the use of a mask. Selective irradiation can be performed in various ways. For example, irradiation of different intensities at different points can give variable irradiation, or laser or similar light sources can be used to irradiate a selected area of the irradiation source in a selected area, followed by curing the surface with a conventional light source The rest of the area. A layer of curable composition formulation can be used as a single film over the entire area of the device, or for example, three different inkjet print heads can deposit three different ink formulations over each R, G, and B sub-pixel. Each of the three formulas can be fine-tuned to correct the defects of each emission wavelength.

After the curable composition is deposited, the first (low) radiation intensity can be used to form the scattering domain and lock it into the cross-linked matrix. The second radiation pulse (with higher intensity) can be used to complete the curing of the remaining acrylate monomer. Higher intensity may also lead to phase-separated fluoropolymer domains, but these domains are extremely small and are considered optically insignificant. Other uses of such domain-sized multi-peaks or gradient distributions can also be considered, such as for some degree of light steering or optical focusing.

Once polymerization starts, an optical scattering layer is formed. As mentioned above, three different types of regions can be formed in the layer. The optical scattering layer includes a matrix and phase-separated microdomains. The microdomains can be rich in fluoropolymers or rich in (meth)acrylates. Without being bound by theory, since it is believed that the formation of microdomains is limited by diffusion, the speed of formation of the cross-linked poly(meth)acrylate matrix can directly affect the size of the microdomains. Since the curing speed of the poly(meth)acrylate matrix can be directly affected by changing the intensity of the curing radiation, we expect to be able to use different light intensities to Pattern different levels of scattering. For example, low light intensity can be used to produce large fluoropolymer or acrylate microdomains in one area of the layer, and high light intensity can be used to produce small fluoropolymer or (meth)acrylic acid in another area of the layer Ester microdomains. In each of the layer regions, different domain sizes will cause changes in haze and optical scattering. According to Mie theory, assuming that particles are smaller than the wavelength of light, the intensity of scattered light is proportional to the square of the difference in refractive index between the two phases and the sixth power of the radius of the dispersed phase. Other ways to affect the curing speed include changing the functionality, viscosity, and molecular weight of the (meth)acrylate monomer used in the resin mixture. In this way, when selective curing is performed, the radiation exposure of different regions of the cured composition layer is different, and the formation of microdomains is also different. In other words, selective curing can produce light diffusing layers with different microdomains at different points on the layer. For particle-based light diffusing layers or for the light diffusing layers described in US Patent No. 9,238,762 (Schaffer et al.), this selectivity is not possible because these light diffusing layers are at all points of the layer identical.

The method of the present disclosure can be further understood through FIGS. 1A to 1I. 1A to 1I illustrate a wide range of curing methods that can be used to produce the optical scattering layer of the present disclosure. It should be noted that the figures are intended to be illustrative and not to scale.

FIG. 1A shows a curable layer including a substrate layer 10A , wherein the curable composition 20A is disposed on the substrate layer. The curable composition was exposed to actinic radiation 30A . Actinic radiation is generally UV light, and it cures the curable composition 20A to form a cured matrix 50A with phase-separated microdomains 40A .

FIG. 1B shows a curable layer including a substrate layer 10B , wherein the curable composition 20B is disposed on the substrate layer. The curable composition is exposed to actinic radiation 31B, 32B, and 33B of different intensities (shown as I ₁ , I ₂ , and I ₃ ). Actinic radiation 31B has an intensity I ₁ , actinic radiation 32B has an intensity I ₂ , and actinic radiation 33B has an intensity I ₃ , where the relative intensity of actinic radiation is: I ₁ <I ₂ <I ₃ . Actinic radiation is generally UV light, and it cures the curable composition 20B to form a cured matrix 50B having phase separated microdomains 41B, 42B, and 43B . The sizes of the phase-separated microdomains 41B, 42B, and 43B are shown to be different. Although the phase-separated microdomains 41B, 42B, and 43B are different, it should be noted that the size is representative and not proportional.

FIG. 1C shows a curable layer including a substrate layer 10C , wherein the curable composition 20C is disposed on the substrate layer. The curable composition is exposed to actinic radiation 31C, 32C, and 33C of different intensities. The intensity of actinic radiation 31C is lower than the intensity of actinic radiation 32C , and the intensity of actinic radiation 33C is lower than that of actinic radiation 32C , and may be the same as or may be different from the intensity of actinic radiation 31C . Actinic radiation is generally UV light, and it cures the curable composition 20C to form a cured matrix 50C with phase separated microdomains 41C, 42C, and 43C . The sizes of the phase-separated microdomains 41C, 42C, and 43C are shown to be different. Although the phase-separated microdomains 41C, 42C, and 43C are different, it should be noted that the size is representative and not proportional.

FIG. 1D shows a curable layer including a base material layer 10D , wherein the curable composition layers including the curable composition sublayers 21D, 22D, and 23D are disposed on the base material layer. In this embodiment, the curable composition sublayer may represent, for example, curable compositions with different viscosities. Three sub-layers are shown for clarity, but it should be understood that a wide range of sub-layer systems are possible. Sublayers can be generated by the intensity gradient of light received throughout the film body. For example, a film containing molecules that absorb ultraviolet radiation (such as an ultraviolet absorber) can receive a higher light intensity on the top of the film than on the bottom of the film. The curable composition is exposed to actinic radiation 30D . Actinic radiation is generally UV light, and it cures the curable composition sublayers 21D, 22D, and 23D to form a cured matrix 50D with phase-separated microdomains 41D, 42D, and 43D . The sizes of the phase-separated microdomains 41D, 42D, and 43D are shown to be different. Although the phase-separated microdomains 41D, 42D, and 43D are different, it should be noted that the size is representative and not to scale.

FIG. 1E shows a curable layer including a base material layer 10E , and a curable composition layer including curable composition sublayers 21E and 22E is disposed on the base material layer. In this embodiment, the curable composition sublayer is different because the surface sublayer 22E is exposed to an oxygen atmosphere because the curable article is not present in an inert atmosphere (such as nitrogen). The curable composition is exposed to actinic radiation 30E . Actinic radiation is generally UV light, and it cures the curable composition sublayers 21E and 22E to form a cured matrix 50E with phase-separated microdomains 41E and 42E . It is expected that the presence of oxygen in the surface sublayer 22E will hinder the polymerization rate in this sublayer. The size of the phase-separated microdomains 41E and 42E are shown to be different. Although the phase-separated microdomains 41E and 42E are different, it should be noted that the size is representative and not to scale.

FIG. 1F shows a curable layer including a substrate layer 10F , wherein the curable composition 20F is disposed on the substrate layer. A part of the curable composition 20F is blocked by the mask 60F . The curable composition was exposed to actinic radiation 30F . Due to the mask 60F , only a part of the curable composition 20F receives actinic radiation 30F . Actinic radiation is generally UV light, and it cures the curable composition 20F to form a cured matrix 50F , where the cured matrix has phase-separated microdomains 40F in the area that receives radiation 30F . Remove the mask 60F and expose the composition to actinic radiation 30F' . Actinic radiation 30F' may be the same as or different from actinic radiation 30F . Actinic radiation is generally UV light, and it cures the uncured curable composition to form a cured matrix 51F , where the cured matrix has phase-separated microdomains 41F and 42F in the area that receives radiation 30F' .

FIG. 1G shows a curable layer including a base material layer 10G , wherein the curable composition 20G is disposed on the base material layer. A part of the curable composition 20G is exposed to actinic radiation 70G . The actinic radiation 70G may be a laser, for example. Because the light source 70G is narrow, only a part of the curable composition 20G receives actinic radiation. Actinic radiation cures the curable composition 20G to form a cured matrix 50G , where the cured matrix has phase-separated microdomains 40G in the region that receives radiation 70G . Expose the composition to actinic radiation 30G . Actinic radiation 30G is generally exposed to the entire surface of UV light, and it cures the uncured curable composition to form a cured matrix 51G , where the cured matrix has phase-separated microdomains 41G and 30G in the region that receives radiation 30G . 42G .

FIG. 1H shows a curable layer including a substrate layer 10H , wherein the curable composition 20H is disposed on the substrate layer. The curable composition 20H contains nanoparticles 80H . The curable composition 20H is exposed to actinic radiation 30H . Actinic radiation is generally UV light, and it cures the curable composition 20H to form a cured matrix 50H with phase-separated microdomains 40H . The surface of these nanoparticles can be engineered as seed crystals for nucleation phase separation, or it can be used for other functions, such as modifying the refractive index.

FIG. 1I shows a curable layer, which includes a substrate layer 10I , wherein the curable composition 20I is disposed on the substrate layer. The tool film 90I has a microstructured pattern in a surface. In step 100 , the tool film 90I is brought into contact with the curable composition 20I to form a laminated structure. The curable composition is exposed to actinic radiation 30I . Actinic radiation is generally UV light, and it cures the curable composition 20I to form a cured matrix 50I with phase-separated microdomains 40I . Next, the tool film 90I is removed in step 110 to produce a structured cured layer having a cured matrix 50I and phase separated microdomains 40I .

This disclosure includes the following embodiments:

Some of these embodiments are curable compositions. Example 1 includes a curable composition comprising: at least one fluoropolymer; at least one monofunctional (meth)acrylate; at least one difunctional (meth)acrylate; and at least one initiator.

Embodiment 2 is the curable composition of embodiment 1, wherein the curable composition does not contain a solvent and has a viscosity of less than 30 centipoise at a temperature of room temperature to 60°C.

Embodiment 3 is the curable composition of embodiment 1 or 2, wherein the at least one monofunctional (meth)acrylate comprises a monofunctional alicyclic (meth)acrylate.

Embodiment 4 is the curable composition of any one of embodiments 1 to 3, wherein the at least one monofunctional (meth)acrylate comprises a monofunctional alicyclic methacrylate.

Embodiment 5 is the curable composition of any one of embodiments 1 to 4, wherein the at least one difunctional (meth)acrylate comprises a bifunctional aliphatic (meth)acrylate.

Embodiment 6 is the curable composition of any one of embodiments 1 to 5, wherein the at least one difunctional (meth)acrylate comprises a bifunctional aliphatic methacrylate.

Embodiment 7 is the curable composition of any one of embodiments 1 to 6, wherein the bifunctional (meth)acrylate accounts for 1 to 20 based on the total weight of the curable components of the curable composition Parts by weight.

Embodiment 8 is the curable composition of any one of embodiments 1 to 7, wherein the at least one fluoropolymer accounts for 1 to 20% by weight based on 100% by weight of the total curable composition.

Embodiment 9 is the curable composition of any one of embodiments 1 to 8, wherein the at least one fluoropolymer comprises an amorphous fluoropolymer, and the amorphous fluoropolymer comprises a fluorine content of 60 to 70%.

Embodiment 10 is the curable composition of any one of embodiments 1 to 9, wherein the at least one fluoropolymer comprises fluoroelastomer.

Embodiment 11 is the curable composition of any one of embodiments 1 to 10, which further comprises at least one copolymerizable vinyl monomer.

Embodiment 12 is the curable composition of embodiment 11, wherein the copolymerizable polyvinyl monomer comprises N-vinylpyrrolidone or N-vinylcaprolactam monomer.

Embodiment 13 is the curable composition of any one of embodiments 1 to 12, further comprising at least one additive selected from the group consisting of metal oxide nanoparticles, adhesion promoters, functional polymers, heat stabilizers, Ultraviolet light stabilizer, free radical scavenger, chain transfer agent, photosensitizer, and combinations thereof.

Also revealed are items. Embodiment 14 includes an article comprising: a substrate having a first main surface and a second main surface; and an optical scattering layer on the first main surface of the substrate, wherein the optical scattering layer is prepared from A curable composition, wherein the curable composition comprises: at least one fluoropolymer; at least one monofunctional (meth)acrylate; at least one difunctional (meth)acrylate; and at least one initiator; and wherein The optical scattering layer includes a matrix and phase-separated microdomains, wherein the matrix and the phase-separated microdomains have different refractive indices, and wherein the microdomains are approximately or greater than the wavelength of visible light.

Embodiment 15 is the article of embodiment 14, wherein the optical scattering layer has at least one of three types of regions, wherein: the first type region includes a (meth)acrylate matrix, and the (meth)acrylate matrix A phase separation microdomain with a fluorocarbon-rich compound; the second type region includes a (meth)acrylate matrix with a phase separation microdomain with a fluorocarbon-rich compound, wherein the rich The fluorocarbon-containing phase-separated microdomain further includes a (meth)acrylate-rich nanodomain; and the third type region includes a fluorocarbon-rich matrix, the fluorocarbon-rich matrix has a rich Phase separation microdomains of (meth)acrylate.

Embodiment 16 is the article of embodiment 15, wherein the optical scattering layer includes at least two of the three types of regions.

Embodiment 17 is the article of embodiment 15, wherein the optical scattering layer includes three types of regions.

Embodiment 18 is the article of any one of embodiments 14 to 17, wherein at least some of the phase-separated microdomains include fluorocarbon-rich microdomains.

Embodiment 19 is the article of any of embodiments 14 to 18, wherein the phase-separated microdomains are 100 to 4,000 nanometers.

Embodiment 20 is the article of any one of embodiments 14 to 18, wherein the phase-separated microdomains are 400 to 2,000 nanometers.

Embodiment 21 is the article of any one of embodiments 14 to 18, wherein the phase-separated microdomains are 400 to 1,000 nanometers.

Embodiment 22 is the article of any of embodiments 14 to 18, wherein the phase-separated microdomains are 400 to 700 nanometers.

Embodiment 23 is the article of any one of embodiments 14 to 22, wherein the optical scattering layer containing phase-separated microdomains includes regions with different concentrations of phase-separated microdomains, different-sized phase-separated microdomains, or a combination thereof .

Embodiment 24 is the article of embodiment 23, wherein the optical scattering layer includes regions with different concentrations of phase-separated microdomains, different-sized phase-separated microdomains, or a combination thereof, including the concentration difference across the thickness of the layer.

Embodiment 25 is the article of embodiment 23, wherein the optical scattering layer includes regions with different concentrations of phase-separated microdomains, different-sized phase-separated microdomains, or a combination thereof, including the concentration in the length and width regions of the layer difference.

Embodiment 26 is the article of any of embodiments 14 to 25, wherein the optical scattering layer has a thickness of 1 to 76 microns.

Embodiment 27 is the article of any one of embodiments 14 to 25, wherein the optical scattering layer has a thickness of 1 to 51 microns.

Embodiment 28 is the article of any one of embodiments 14 to 25, wherein the optical scattering layer has a thickness of 1 to 25 microns.

Embodiment 29 is the article of any one of embodiments 14 to 28, wherein the article includes a display article.

Embodiment 30 is the article of any of embodiments 14 to 29, wherein the optical scattering layer includes a structured surface.

Embodiment 31 is the article of embodiment 30, wherein the structured surface comprises a microstructured surface.

Also disclosed are methods of making articles. Embodiment 32 includes a method of preparing an article, the method comprising: providing a substrate having a first main surface and a second main surface; providing a curable composition comprising: at least one fluoropolymer; at least one monofunctional ( Meth)acrylate; at least one bifunctional (meth)acrylate; and at least one initiator; forming a layer of curable composition on at least a portion of the first major surface of the substrate; curing the layer curable Composition to form a cured optical scattering layer, comprising: an optical scattering layer on a first major surface of the substrate, wherein the optical scattering layer includes a matrix and phase-separated microdomains, wherein the matrix and the phases are separated The micro-domains have different refractive indexes, and the micro-domains are approximately or greater than the wavelength of visible light.

Embodiment 33 is the method of embodiment 32, wherein the curable composition contains no solvent and has a viscosity of less than 30 centipoise at a temperature of room temperature to 60°C.

Embodiment 34 is the method of embodiment 32 or 33, wherein forming a layer of curable composition on at least a portion of the first major surface of the substrate comprises printing the curable composition.

Embodiment 35 is the method of embodiment 34, wherein printing comprises inkjet printing.

Embodiment 36 is the method of any one of embodiments 32 to 35, wherein the phase-separated microdomains are 100 to 4,000 nanometers.

Embodiment 37 is the method of any one of embodiments 32 to 35, wherein the phase-separated microdomains are 400 to 2,000 nm.

Embodiment 38 is the method of any one of embodiments 32 to 35, wherein the phase-separated microdomains are 400 to 1,000 nanometers.

Embodiment 39 is the method of any one of embodiments 32 to 35, wherein the phase-separated microdomains are 400 to 700 nm.

Embodiment 40 is the method of any one of embodiments 32 to 39, wherein curing includes pattern curing the selected regions of the layer so that the layer includes a series of phase-separated microdomains.

Embodiment 41 is the method of embodiment 40, wherein pattern curing includes exposing different regions of the layer to different levels of radiation.

Embodiment 42 is the method of embodiment 40, wherein pattern curing includes applying a photomask over a portion of the layer and exposing the layer to radiation.

Embodiment 43 is the method of embodiment 42, further comprising removing the reticle and exposing the layer to irradiation, wherein the radiation is different from the irradiation used when the reticle is in place.

Embodiment 44 is the method of embodiment 40, wherein the pattern curing includes using a laser to cure selected areas of the layer.

Embodiment 45 is the method of embodiment 44, further comprising curing the rest of the layer by exposure to radiation.

Embodiment 46 is the method of any one of embodiments 32 to 45, wherein the cured optical scattering layer has a thickness of 1 to 76 microns.

Embodiment 47 is the method of any one of embodiments 32 to 45, wherein the cured optical scattering layer has a thickness of 1 to 51 microns.

Embodiment 48 is the method of any one of embodiments 32 to 45, wherein the cured optical scattering layer has a thickness of 1 to 25 microns.

Examples

Preparation of curable ink composition. The material was applied to the substrate, and the physical, optical, and mechanical properties were evaluated as shown in the following examples. These examples are for illustrative purposes only and are not intended to limit the scope of the accompanying patent application. All parts, percentages, ratios, etc. in the examples and the rest of the description are by weight unless otherwise stated. The solvents and other reagents used were obtained from Sigma-Aldrich Chemical Company, St. Louis, Missouri, unless otherwise noted. The following abbreviations are used in this article: nm=nanometer; mm=millimeter; cm=centimeter; um=micrometer; m=meter; N=Newton; mW=milliwatt; min=minute; K=1,000 (ie, 15KDa=15,000 Dalton molecular weight); Hz=Hertz; cPs=centipoise; mol=mole; ℃=degrees Celsius; T=transmittance; H=haze; C=sharpness, avg=average, and stdev=standard deviation. The terms wt% and weight% are used interchangeably.

testing method Sample preparation

A winding bar (model: RDS10, RDS Specialties, Webster, NY) was used to manufacture the coating for optical testing on the substrate S1. Immediately after coating with a CA-3200 UV-LED curing chamber (λ=365 to 400 nm, Clearstone Technologies Inc., Hopkins, MN) with integrated N2 purge, ultraviolet (UV) curing of the film was performed.

The sample was prepared by sandwiching the resin between two pieces of base PET (S1) substrate. The S1/resin/S1 stack is then placed on a reticle (IG1) patterned with chromium of different thicknesses to achieve several discrete intensity levels across the sample when UV radiation passes through the reticle. Place another piece of bare glass over the top of the S1/Resin/S1 stack, and then clamp the entire construction in close contact with the adhesive clamp. A thick piece of black plastic is placed on top of the sandwich structure to prevent UV reflection from the top of the curing chamber during curing. Curing was performed through the photomask for 30 minutes, followed by 15-minute full-face exposure with a UV intensity of 95.6 mW/cm ² without a photomask. As described in Table 4 and Table 5, a light meter (UV PowerPuck II, Electronic Instrumentation and Technology Inc., Sterling, VA) was used to measure the light intensity passing through each of the photomask regions.

Test Method 1: Transmittance, haze, clarity, and b* measurement

Using a haze meter (BYK Gardiner, brand name "BYK HAZEGARD Plus, Columbia, MD") based on ASTM D1003-13, transmittance, haze, average% of clarity, and b* were measured. The results are recorded in Table 5.

Test Method 2: Viscosity test

17 mL of each ink formulation was loaded into a 25 mm diameter double gap coaxial concentric cylinder device (DIN 53019) on a viscometer (BOHLIN VISCO 88, Malvern Instruments Ltd, Malvern, UK). The thermal jacket equipped with the double-gap unit heats the circulating water flow to 25°C and 35°C, respectively. Before making each measurement, the system was allowed to equilibrate for 30 minutes. Raise the shear rate from 100 to 1000 Hz at 100 Hz intervals and repeat the measurement three times. Take the average and standard deviation of all data points as the viscosity, the unit is centipoise. The results are recorded in Table 3.

Test Method 3: Atomic Force Microscope Measurement (AFM)

A Leica EM UC6 microtome was used to cut the cross-section of the cured resin sample between the substrates S1 at room temperature. An atomic force microscope was used to image the cross-section of the phase-separated ink coating. The imaging system is in Bruker operating in tapping mode Dimension Icon microscope (Bruker Nano Inc., 112 Robin Hill Road, Santa Barbara, CA 93117) was performed under ambient conditions in the air. During operation, a Bruker OTESPA silicon cantilever tip with an aluminum backside coating (nominal spring constant = 40 N/m, nominal frequency = 300 kHz, nominal tip radius = 8 nm) was used. The image size is 20×20 microns, with 1024×1024 data points. Perform domain size analysis on the three images of each sample at each light intensity. Use Nanoscope Analysis v1.7 (Bruker, Santa Barbara, CA) software to accurately measure the size of each measurement. The average and standard deviation are recorded and listed in Table 4.

Test Method 4: Atomic Force Microscope-Infrared Spectroscopy (AFM-IR)

The samples were frozen and sectioned to obtain 250 nm cross-section slides for AFM-IR studies. Frozen sectioning was performed at -40°C using the Leica ultrathin microtome EM UC7 unit. Then, the cross-sectional slices were transferred to a 10 mm×10 mm ZnS single crystal plane for AFM-IR testing.

A nano-IR2-FS platform (Bruker Anasys, Santa Barbara, CA) was used for AFM-IR experiments. Thin-section slices were examined in contact mode using a gold-coated SiN AFM tip (Anasys Instruments) with a nominal tip radius of 20 nm. Fine-tune the repetition rate of the IR laser to match the second contact resonance of the AFM cantilever to enhance sensitivity. All measurements are made under ambient conditions.

The cross ^- sections of the film samples are IR mapped at two characteristic laser frequencies of 1730 cm ^-1 and 1210 cm ^-1 , which are characteristic IR absorption bands of methacrylate and fluoroelastomer, respectively.

Examples formula

Produce a stock solution of pure fluoroelastomer in each of the methacrylate monomers. The fluoroelastomer sheet was cut from a larger block into small squares of 2×2 mm, and added to each of the pure methacrylate monomers in an amber vial. Place the vial on the roller for two days or until a clear homogeneous solution is formed. Remove an aliquot from the stock solution bottle and mix it with other components. 80:20 mol:mol ratio of mono-functional monomer: bi-functional mono-system is used in the photo-curable part of the formulation of most examples. The photoinitiator (PH1) and spacer beads (B1) were added relative to the total weight of the fluoropolymer/monomer solution. The solution was sonicated for 30 minutes or until a homogeneous blend was formed. See Table 2 for the recipes used in each example.

AFM and AFM-IR images

2 and 4 show optical micrographs of the cross-sections of the films produced in Example 2 and Example 1, respectively, and were analyzed by Test Method 3: Atomic Force Microscope. Atomic force microscope IR mapping clearly shows the spatial distribution of methacrylate and fluoropolymer, which confirms the obvious phase separation. AFM-IR technology is used to map the chemical composition on the 30μm×30μm area of this profile, and at the same time fix the frequency of the IR laser at 1730cm ^-1 and 1210 cm ^{-1 respectively} . The IR mapping at 1730 cm ^-1 and 1210 cm ^-1 is depicted in FIGS. 3B and 3C. Figure 3A shows the AFM topography map obtained simultaneously with the IR map. Figures 3B and 3C clearly identify the obvious chemical separation between the fluoropolymer phase and the methacrylate phase. The image matrix in FIG. 3B has a lighter color on the data scale, indicating that this region has higher IR absorption at 1730 cm ^-1 , which corresponds to the C=O (carbonyl chemical moiety) stretching mode in the methacrylate phase. Figure 3C identifies these microdomains as having a higher IR absorption at 1210 cm ^-1 , which corresponds to the CF extension mode in the fluoroelastomer phase. This color inversion between Figure 3B and Figure 3C means that the matrix is rich in methacrylate and the microdomain is rich in fluoroelastomer. In addition, careful observation of the inside of the microdomains of the fluoroelastomer revealed the nanodomains of the methacrylate phase, which indicates a more complicated phase separation phenomenon. In order to eliminate image artifacts caused by topography, the absorption intensity ratio of the IR map is calculated. The built-in software of nanoIR2-FS equipment (Bruker Anasys, Santa Barbara, CA) was used to calculate the absorption intensity ratio of IR mapping. The absorption ratio at two IR laser frequencies is calculated for each pixel on the map. Figure 3D shows the ratio of the absorption intensity of the 1210 cm ^-1 map to the 1730 cm ^-1 map. The greatly improved contrast clearly depicts the phase separation morphology of methacrylate and fluoropolymer. Similarly, Figure 5 shows the topography map and chemical map of Example 1. As shown in the two IR maps (Figures 5B and 5C) and the image ratio (Figure 5D), the spherical methacrylate-rich domains are dispersed in the fluoroelastomer-rich matrix, which is the same as in Figure 3 The phase separation pattern is completely opposite.

10A‧‧‧Base layer

20A‧‧‧curable composition

30A‧‧‧actinic radiation

40A‧‧‧phase separation microdomain

50A‧‧‧cured matrix

Claims (24)

A curable composition comprising: At least one fluoropolymer; At least one monofunctional (meth)acrylate; At least one bifunctional (meth)acrylate; and At least one initiator. The curable composition according to claim 1, wherein the curable composition does not contain a solvent and has a viscosity of less than 30 centipoise at a temperature of room temperature to 60°C. The curable composition according to claim 1, wherein the at least one monofunctional (meth)acrylate comprises a monofunctional alicyclic (meth)acrylate. The curable composition of claim 1, wherein the at least one monofunctional (meth)acrylate comprises a monofunctional alicyclic methacrylate. The curable composition of claim 1, wherein the at least one difunctional (meth)acrylate comprises a difunctional aliphatic (meth)acrylate. The curable composition of claim 1, wherein the at least one difunctional (meth)acrylate comprises a difunctional aliphatic methacrylate. The curable composition according to claim 1, wherein the bifunctional (meth)acrylate accounts for 1 to 20 parts by weight based on the total weight of the curable components of the curable composition. The curable composition according to claim 1, wherein the at least one fluoropolymer accounts for 1 to 20% by weight based on 100% by weight of the total curable composition. The curable composition according to claim 1, wherein the at least one fluoropolymer contains an amorphous fluoropolymer, and the amorphous fluoropolymer contains a fluorine content of 60 to 70%. The curable composition of claim 1, wherein the at least one fluoropolymer contains fluorine Elastomer. The curable composition according to claim 1, further comprising at least one copolymerizable vinyl monomer. The curable composition according to claim 11, wherein the copolymerizable polyvinyl monomer comprises N-vinylpyrrolidone or N-vinylcaprolactam monomer. An article that contains: A substrate having a first main surface and a second main surface; and An optical scattering layer on the first main surface of the substrate, wherein the optical scattering layer is prepared from a curable composition, wherein the curable composition includes: At least one fluoropolymer; At least one monofunctional (meth)acrylate; At least one bifunctional (meth)acrylate; and At least one initiator; and wherein the optical scattering layer includes a matrix and phase-separated microdomains, wherein the matrix and the phase-separated microdomains have different refractive indices, and wherein the microdomains are approximately or greater than the wavelength of visible light. The article of claim 13, wherein the optical scattering layer has at least one of three types of regions, wherein: The first type zone contains a (meth)acrylate matrix, the (meth)acrylate matrix has phase separation microdomains rich in fluorocarbon compounds; The second type region includes a (meth)acrylate matrix having phase separation microdomains rich in fluorocarbon compounds, wherein the phase separation microdomains rich in fluorocarbon compounds further include rich Nano domains containing (meth)acrylate; and The third type zone contains a fluorocarbon-rich matrix that has phase separation microdomains rich in (meth)acrylate. The article of claim 14, wherein the optical scattering layer includes at least two of the three types of regions. The article of claim 13, wherein the phase-separated microdomains are 100 to 4,000 nanometers. The article of claim 13, wherein the optical scattering layer containing phase-separated micro-domains includes regions with different concentrations of phase-separated micro-domains, phase-separated micro-domains of different sizes, or a combination thereof. The article of claim 13, wherein the optical scattering layer has a thickness of 1 to 76 microns. An item as in claim 13, wherein the item includes a display item. The article of claim 13, wherein the optical scattering layer includes a structured surface. A method of preparing an article, comprising: Provide a substrate having a first main surface and a second main surface; Provide a curable composition comprising: At least one fluoropolymer; At least one monofunctional (meth)acrylate; At least one bifunctional (meth)acrylate; and At least one initiator, wherein the curable composition has a viscosity of less than 30 centipoise at a temperature of room temperature to 60°C, Forming a layer of curable composition on at least a portion of the first major surface of the substrate; Curing the layer of the curable composition to form a cured optical scattering layer, the cured optical scattering layer comprising: An optical scattering layer on the first main surface of the substrate, wherein the optical scattering layer includes a matrix and phase-separated microdomains, wherein the matrix and the phase-separated microdomains It has different refractive indexes, and the micro-domains are approximately or greater than the wavelength of visible light. The method of claim 21, wherein the phase-separated microdomains have a size in the range of 100 to 4,000 nanometers. The method of claim 21, wherein curing comprises pattern-wise curing selected areas of the layer such that the layer contains a series of phase-separated microdomains. The method of claim 21, wherein the cured optical scattering layer has a thickness of 1 to 76 microns.

Images