WO2015156479A1 - Polymer composition for transparent substrate, containing silica nanotubes, and plastic thin film composite sheet using same - Google Patents

Abstract

Provided are a polymer composition for a transparent substrate, which is synthesized from a transparent organic polymer as a base material of the plastic thin film composite sheet and 0.1-10wt% of silica nanotubes on the basis of the total weight of the composition; and a plastic thin film composite sheet using the same, of which the flexure determined by the 85/85 test is 1mm or less. In addition, provided is a transparent window substrate for a display using the same.

Description

Polymer composition for transparent substrates including silica nanotubes and plastic thin film composite sheet using same

The present invention relates to a polymer composition for a transparent substrate including silica nanotubes and a plastic thin film composite sheet using the same, and more particularly, to a transparent substrate in which silica nanotubes are added to a transparent organic polymer constituting the base substrate of the plastic thin film composite sheet. It relates to a polymer composition and a plastic thin film composite sheet using the same, a transparent window substrate for a display.

Important commercial products including optically functional products such as display windows, IT parts, solar light, furniture, home appliances, automotive interiors, decor films, etc. of various electronic products including mobile phone LCD screens with keypads in the past have been known for their transparency, water resistance, Plastic multi-layer sheet has been used which has good processability and low cost.

Among the multilayered plastic sheets, polycarbonate (Poly Carbonate, PC) and polymethyl methacrylate (PMMA) were the most commonly used. In particular, recently, multilayer sheets combining the advantages of PC and PMMA have been widely used (hereinafter referred to as PC / PMMA multilayer sheet). It is composed of a base substrate composed mainly of polycarbonate and a skin layer composed mainly of polymethylmethacryl. The base substrate polycarbonate has good water resistance, heat resistance, and impact resistance, but it has disadvantages in surface hardness and weather resistance. It is used as a two-layer or three-layer structure in a multi-layered structure with a skin layer made of polymethylmethacryl for reinforcement.

According to the prior art document 1 (Patent No. 10-2013-0074167), a thin plastic substrate including a hard coating layer is provided, but as the plastic substrate becomes thinner and larger in area, bending due to the characteristics of the sheet made of plastic material ), There are still problems that are vulnerable to scratches, wear, hardness, and the like. In particular, touch screen panels are used instead of keypads, and in the case of smart phones in a large area, the problem is more serious.

In order to compensate for these problems, tempered glass has been used as a substitute for PC / PMMA multilayer sheets, but it has a disadvantage that it is heavier than the plastic substrate and has a low impact strength, which is easy to break, and the defect rate and the cost are high in processing the product.

The present invention is to provide a transparent substrate polymer composition containing silica nanotubes in order to solve the problems of the conventional PC / PMMA multilayer sheet and tempered glass as described above.

Another object of the present invention is to provide a plastic thin film composite sheet having high strength and hardness, light weight, good processability, and low processing cost without losing transparency using the polymer composition for transparent substrate.

In another aspect, the present invention is to provide a transparent window substrate for a display using the plastic thin film composite sheet.

It has a space in the tube wall, the silica nanotubes having a length of 0.1 ~ 1000nm, the inner diameter 40 ~ 50nm, the outer diameter 80 ~ 90nm, the content of the silica nanotubes is 0.1 to 10% by weight relative to the total weight of the polymer composition for transparent substrate A polymer composition for transparent substrates is provided.

A base substrate made of the polymer composition for transparent substrate; And a first skin layer formed on one surface or both surfaces of the base substrate, and provides a plastic thin film composite sheet having a bending by 85/85 test of 1.0 mm or less.

The present invention also provides a transparent window substrate for a display comprising the plastic thin film composite sheet and further comprising at least one of a hard coating layer, a fingerprint coating layer, and a composite coating layer.

The present invention provides a plastic thin film composite sheet and a transparent window substrate for display having high hardness (impact resistance), optical transparency, low processability and low processing cost by using a polymer composition for transparent substrates including silica nanotubes. Can provide.

1 is a cross-sectional view of a plastic multilayer sheet.

2 is a cross-sectional view of a transparent window substrate for a display including a hard coat layer.

3 is a cross-sectional view of a transparent window substrate for a display including an anti-fingerprint coating layer.

4 is a cross-sectional view of a transparent window substrate for a display including a hard coat layer and a fingerprint coating layer.

Prior to describing the present invention in detail below, it is understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention, which is limited only by the scope of the appended claims. shall. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise indicated.

Throughout this specification and claims, unless otherwise indicated, the termcomprise, constitutes, and configure means to include the referenced article, step, or group of articles, and step, and any other article It is not intended to exclude a stage or group of things or groups of stages.

On the other hand, various embodiments of the present invention can be combined with any other embodiment unless clearly indicated to the contrary. Any feature indicated as particularly preferred or advantageous may be combined with any other feature and features indicated as preferred or advantageous. Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and embodiment of the present invention, the effect according to it.

Polymer composition for transparent substrates

The present invention includes a transparent substrate polymer composition in which silica nanotubes (SNT) are added to a transparent organic polymer as an embodiment.

The transparent organic polymer is polycarbonate (Poly Carbonate, PC), polyethylene (Poly Ethylene, PE), polypropylene (Poly Propylene, PP), ethylene vinyl acetate (Ethylene Vinyl Acetate, EVA), poly vinyl chloride (Poly Vinyl Chloride, PVC), Polyamide (PA), Polyurethane (PU), Poly Methyl Methacrylate (PMMA), Poly Vinyl Acetate (PVAC), Polyethylene phthalate , PET), polyimide (Polyimide, PI), poly butylene terephthalate (Poly Butylene Terephthalate (PBT)) may include any one or more. It is preferable to include polycarbonate in order to provide a polymer composition for transparent substrates having excellent impact resistance, good dimensional stability, transparent, light and easy processing.

The polycarbonate synthesis method includes a transesterification method in which bisphenol A (BPA) and diphenyl carbonate (Di-Phenyl Carbonate, DPC) are melted and reacted under reduced pressure and high temperature. Another method for synthesizing polycarbonates is the phosgene method of reacting bisphenol A with phosgene.

The method for forming the polymer composition for transparent substrates will be described as an example in which the transparent organic polymer is polycarbonate. First, there is a method of adding silica nanotubes directly to the synthesized polycarbonate. The addition ratio of the silica nanotubes may be added in an amount of 0.1 to 10% by weight based on the total weight of the polymer composition for a transparent substrate. Preferably it may be added in 1 to 5% by weight. It is difficult to obtain high strength below the above range, and deflection improvement may be insufficient. If the above range is exceeded, optical properties and dispersibility may be a problem.

Secondly, there is a method of adding silica nanotubes at the time of polycarbonate polymerization. In the transesterification process, silica nanotubes are added together when melting the bisphenol A and the diphenylcarbonate as precursors, or the silica nanotubes are reacted with the phosgene (Phosgene) together with the bisphenol A as the precursor in the phosgene method. To form a polycarbonate composition. The addition ratio of the silica nanotubes may be added in an amount of 0.1 to 10% by weight, preferably 1 to 5% by weight, based on the total weight of the precursor. It is difficult to obtain high strength below the above range, and deflection improvement may be insufficient. If the above range is exceeded, optical properties and dispersibility may be a problem.

One of the methods for preparing the added silica nanotubes is the Sol-Gel Template Method (SGTM). More specifically, the first space-forming step of adding water and ethanol to the template to heat until the solution becomes transparent and then holding it while stirring; An addition step of further adding a silica precursor and stirring it vigorously and storing it at room temperature and still state; And a second space forming step of recovering the template using ethanol. Silica nanotubes synthesized in this way exhibit higher alignment and higher silica crystallinity compared to silica nanotubes synthesized in the usual way and have a space in the tube wall.

The template may be a peptide-based template, for example, may be selected from glycylalkylamide having an alkyl group having 8 to 18 carbon atoms. Preferably, at least one selected from glycyldodecylamide (GDA), 2-amino-N-dodecylacetamide, 2-amino-N-decylacetamide, 2-amino-N-tetradecylacetamide, It is good to use.

In the first space forming step, the size of the silica nanotubes may be adjusted according to the stirring temperature. The silica nanotubes synthesized when the template was stirred at 2 ° C. had a cylindrical shape with a length of 0.1-1000 nm, an internal diameter of 40-50 nm, an outer diameter of 80-90 nm, and when the template was stirred at room temperature, the synthesized silica nanotubes had a length of 0.1 to 1000nm, the inner diameter may be 2-3nm, the outer diameter may be 10-30nm.

Through the temperature control in the first space forming step, it is possible to provide two kinds of silica nanotubes at the same time, and economical and environmental advantages in that the relatively expensive template can be easily recovered and used as ethanol. There is this.

The silica precursor in the addition step is not limited, but tetraethoxyorthosilicate (TEOS), tetramethoxyorthosilicate (TMOS), tetra (methylethylketooxymo) silane, vinyloxymosilane (VOS), phenyl One or more types can be selected and used from a tris (butanone oxime) silane (POS) and methyloxymo (MOS). The amount of the silica precursor added is preferably added to 4 ~ 10 mmol with respect to 1.0 mmol of the casting agent. If the amount of the silica precursor is less than 4 mmol, the thickness of the silica may be too thin, which may hinder the stability of the structure. If the amount exceeds 10 mmol, the silica outer wall thickness may be too thick.

The transparent substrate polymer composition may include spherical silica nanopowder as an additive. It may be added to the composition in powder form, and may be added in the form of a sol dispersed in a solvent. When only silica nanotubes are added, the amount of silica nanotubes used may be limited due to the dispersion limit coming from the nanotube structure itself. Therefore, spherical silica powder can be used in parallel to solve the problem of dispersibility while increasing the strength. The content of the silica nanopowder may be included in an amount of 0.1 to 5% by weight based on the total composition, and the total content of the silica nanotubes and the spherical silica nanopowder is in the range of 0.2 to 15% by weight, preferably 1 to 10% by weight, based on the total composition. Can be.

Plastic Thin Film Composite Sheet

Plastic thin film composite sheet is a base substrate 10 made of a polymer composition for transparent substrates according to the present invention; And a first skin layer 20 formed on one or both surfaces of the base substrate.

1 is a cross-sectional view showing the structure of a plastic thin film composite sheet according to an embodiment of the present invention. Figure 1 (a) is a cross-sectional view of a two-layer plastic thin film composite sheet having a first skin layer on one side of the base substrate, (b) is a three-layer plastic with a first skin layer on both sides of the base substrate Sectional drawing of a thin film composite sheet.

The plastic thin film composite sheet manufacturing method is formed by applying, drying, and curing the first skin layer composition on one or both surfaces of the base substrate 10 including the polymer composition for transparent substrates described above, or using two to three extruders. The base substrate composition and the first skin layer composition may be simultaneously extruded and laminated in multiple layers in a molten state to form a plastic thin film composite sheet.

The base substrate composition may be a polymer composition for the transparent substrate described above, it is omitted because it was described above.

The first skin layer composition may be polycarbonate (PC), polyethylene (poly ethylene, PE), polypropylene (PP), ethylene vinyl acetate (Ethylene vinyl acetate, EVA), polyvinyl chloride Chloride, PVC), Polyamide (PA), Polyurethane (PU), Polymethyl Methacrylate (PMMA), Poly Vinyl Acetate (PVAC), Polyethylenephthalate ( Polyethylene phthalate (PET), polyimide (Polyimide, PI), and polybutylene terephthalene (Poly Butylene Terephthalate (PBT)) may include any one or more. It is preferable to include polymethylmethacrylate in order to compensate for the disadvantages of the base substrate having a relatively poor surface hardness and weather resistance.

Silica nanotubes may be added to the first skin layer composition. Addition methods include adding silica nanotubes directly to the synthesized polymethyl methacrylate and adding the polymethyl methacrylate at the time of polymerization. The addition ratio of the silica nanotubes is added at 0.1 to 10% by weight based on the total weight of the first skin layer composition. Preferably it is added 1 to 5% by weight.

The plastic thin film composite sheet of the present invention manufactured by the above method has a high strength (impact resistance), optical transparency, and maintains good workability and low processing cost compared to the conventional plastic thin film composite sheet.

Transparent window board for display

The transparent window substrate for a display according to the present invention is a transparent window substrate for a display installed outside the liquid crystal screen of a mobile device to protect the liquid crystal screen. Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

2 to 4 show the structure of a transparent window substrate for a display according to an embodiment of the present invention as a cross-sectional view. The transparent window substrate for a display according to the present invention includes a coating layer prepared by surface treatment on the plastic thin film composite sheet according to the present invention. 2 and 3, the coating layer may include any one or more of the hard coat layer 31 and the fingerprint coating layer 32. In addition, referring to Figure 4, the two-layer or three-layer plastic thin film composite sheet may include a hard coating layer 31 and an anti-fingerprint coating layer 32, as another embodiment both the hard coating function and the fingerprint function A single layer of the composite coating layer 33 may be included. The composite coating layer 33 may be formed of a mixture of a hard coating composition and a fingerprint coating composition.

In addition, the transparent window substrate for a display according to the present invention is a transparent window substrate for display, characterized by good transparency, lightness and high strength by the physical properties of the silica nanotubes included in the base substrate of the plastic thin film composite sheet.

The hard coating layer is a coating layer for improving the surface hardness, the kind is not limited. Preferably a UV hard coating composition can be used. For example, a silane compound may be used as a precursor. Hard coating composition production method comprises the steps of mixing the silane compound in ethanol and stirring at room temperature; It may comprise the step of stirring at room temperature while slowly adding dropwise to the dilute distilled water and concentrated hydrochloric acid solution. The molar ratio of silane compound: ethanol: distilled water: hydrochloric acid may be 1: 4: 4: 0.03.

The method of coating the prepared hard coating composition on the plastic thin film sheet is not limited, but because it is affected by the environmental atmosphere of coating, it is preferable to coat the plastic thin film sheet according to the present invention by using a glove box in a nitrogen atmosphere in a vacuum state. good. After coating the hard coating composition on the plastic thin film sheet according to the present invention may be dried for 10 minutes at room temperature in order to adhere to the surface may include curing through UV irradiation. On the other hand, the hard coating composition may use a thermosetting hard coating composition. Preferably, the hard coating composition is coated on a plastic thin film composite sheet in which the transparent organic polymer is polycarbonate, but is not limited thereto.

The transparent window substrate for a display including the hard coating layer 31 has a large surface hardness, has a high resistance to scratches, an adhesion with a plastic thin film composite sheet, and a uniform surface quality.

The anti-fingerprint coating layer 32 may be formed by coating the anti-fingerprint coating composition on the plastic thin film composite sheet or on the hard coating layer. As an example, a primary coating step of forming a primary coating layer by coating a primary coating agent containing silicon dioxide, and by coating a secondary coating agent containing fluorine organic siloxane (organic siloxane) on the primary coating layer to form a secondary coating layer It may include a secondary coating step.

The secondary coating agent may include 30 to 50% by weight of the organic siloxane, 5 to 25% by weight of colloidal silica, 5 to 25% by weight of zirconia and 15 to 35% by weight of the solvent based on the total weight of the secondary coating. The organic acid may be any one selected from the group consisting of citric acid, citric acid, lactic acid, sorbic acid, and combinations thereof.

The method of coating the primary coating and the secondary coating is not particularly limited, and for example, a wet method such as dipping, spin coat, roll coat, spray coat, or the like Or a dry method such as PVD (physical vapor deposition) or CVD (chemical vapor deposition) such as vacuum deposition, reactive vapor deposition, ion beam assist, sputtering, or ion plating.

The transparent window substrate for a display including the anti-fingerprint coating layer 32 is excellent in stain resistance and fingerprint resistance.

Claims (8)

1. In the polymer composition for a transparent substrate comprising a transparent organic polymer and silica nanotubes,

   The content of the silica nanotubes is a transparent substrate polymer composition, characterized in that 0.1 to 10% by weight relative to the total weight of the transparent substrate polymer composition.
2. The method of claim 1,

   The transparent organic polymer is polycarbonate, polyethylene, polypropylene, ethylene vinyl acetate, polyvinyl chloride, polyamide, polyurethane, polymethyl methacrylate, polyvinylacetate, polyethylene phthalate, polyimide, polybutylene terephthalene Polymer composition for transparent substrates comprising at least one.
3. The method of claim 1,

   The silica nanotube has a space in the tube wall, the length is 0.1 ~ 1000nm, the inner diameter 40 ~ 50nm, the outer diameter 80 ~ 90nm characterized in that the polymer composition for transparent substrate.
4. A base substrate made of a polymer composition for transparent substrates; And

   A plastic thin film composite sheet comprising a first skin layer formed on one or both surfaces of a base substrate,

   The polymer composition for transparent substrate is a plastic thin film composite sheet, characterized in that 0.1 to 10% by weight of silica nanotubes added to the total weight of the transparent substrate polymer composition.
5. The method of claim 4, wherein

   The silica nanotube has a space in the tube wall, the plastic thin film composite sheet, characterized in that the length is 0.1 ~ 1000nm, the inner diameter 40 ~ 50nm, the outer diameter 80 ~ 90nm.
6. The method of claim 4, wherein

   Plastic thin film composite sheet with a warpage of less than 1.0mm by 85/85 test.
7. A transparent window substrate for a display comprising the plastic thin film composite sheet of claim 4.
8. The method of claim 7, wherein

   Transparent window substrate for display further comprises at least one or more of a hard coating layer, an anti-fingerprint coating layer, a composite coating layer.

Images