KR102059749B1 - Ladder-Structured Polysilsesquioxane/Al2O3 Nanocomposites for Transparent Wear-Resistant Windows - Google Patents

Abstract

The present invention relates to a polysilsesquioxane/Al_2O_3 nano-composite having a ladder structure for a transparent wear-resistant window. A novel organic/inorganic hybrid material according to the present invention can be cured at the low temperature, shows excellent transparency and thermal stability, has excellent mechanical properties such as wear resistance and hardness, and then is used as a display protection film comprising the same or the transparent wear resistant window comprising the same, thereby having a useful effect which can be applied to a deformable display recently attracting attention.

Description

Ladder-Structured Polysilsesquioxane / Al2O3 Nanocomposites for Transparent Wear-Resistant Windows}

The present invention relates to a polysilsesquioxane / Al ₂ O ₃ nanocomposite having a ladder structure for a transparent wear resistant window.

Recently, there is an increasing demand for lightweight, flexible, compact and multifunctional electronic devices, but it still remains a problem for the electronic devices to achieve resistance to mechanical stress exposed in the use environment.

In particular, the use of shape-deformable displays such as foldable, stretchable and flexible displays is expected to grow rapidly in the near future, but due to the demand for the use of polymer-based substrates that are vulnerable to mechanical stress, commercialization is delayed.

As such, since there is a limit in developing a neat polymer that simultaneously exhibits abrasion resistance such as glass and flexibility such as plastic, it is proposed to introduce a protective layer using an organic / inorganic hybrid material as an alternative to improve the durability of the display.

As a class of emerging hybrid materials, polysilsesquioxanes (PSSQ) derived from trifunctional silanes via sol-gel chemistry will provide flexibility due to the low rotational barrier of the framework and rigidity due to the adoption of curable pendant units. Can be.

Specifically, ladder-structured PSSQs (LPSQs) consisting of double strands of ladder chemical structure are attracting attention due to the opposing physical properties of the rigidity due to the adoption of flexible and curable pendant units due to the excellent optical transparency and low rotational barrier of the framework. have.

However, when applied as a protective layer of a deformable display, LPSQ should be able to effectively cure at low temperatures due to the thermal stability of the polymer-based substrate.

In addition, various LPSQs are polymerized to include monomers containing several types of curable moieties, in order to impart high surface hardness to their excellent flexibility, in the case of the most commonly used curing units acrylate or epoxy, UV irradiation Only 50-60% of the curing units are under the problem, and further heat treatment of about 150 ° C. is required for at least 2 hours to ensure the desired level of surface hardness.

Accordingly, the present inventors, while trying to solve the problems of the prior art described above, by using the amine functionalized Al ₂ O ₃ nanoparticles in LPSQ containing a periodic epoxy group, to prepare a LPSQ-Al ₂ O ₃ nanocomposite From this, it was confirmed that the excellent optical transparency and thermal stability, and also the epoxy conversion is improved, and after the light / heat curing process, the mechanical properties such as abrasion resistance, hardness, etc. have been remarkably improved, which can be used for the protective layer of the deformable display. After confirming the applicability, the present invention was completed.

S. Gupta, P. C. Ramamurthy, and G. Madras, Polym. Chem., 2, 221 (2011)

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel organic / inorganic hybrid material which is cured at a low temperature for use as a protective layer of a deformable display, at the same time exhibits excellent transparency and thermal stability, and further improves mechanical properties such as wear resistance and hardness. will be.

Another object of the present invention is to provide a method for producing the novel organic / inorganic hybrid material.

Yet another object of the present invention is to provide a display protective film comprising the novel organic / inorganic hybrid material.

Another object of the present invention is to provide a transparent wear resistant window comprising the novel organic / inorganic hybrid material or the display protective film.

In order to achieve the above object,

In one aspect of the invention,

A curable resin composition comprising a ladder polysilsesquioxane, and a mineral filler is provided.

In another aspect of the invention,

A nanocomposite prepared from the curable resin composition is provided.

In another aspect of the invention,

A display protective film including the nanocomposite is provided.

In another aspect of the invention,

A transparent wear-resistant window comprising the curable resin composition or the display protective film, a protective film for protecting electronic devices, a water repellent coating film for building protection, a UV blocking film, a plastic substrate, a flexible water repellent coating film of a fiber material, or a weatherproof film for wood (building) protection is provided. .

The novel organic / inorganic hybrid material according to the present invention can be cured at a low temperature and at the same time shows excellent transparency and thermal stability, and furthermore, excellent mechanical properties such as abrasion resistance and hardness, and a display protective film comprising the same, or the like. Used as a transparent wear resistant window, there is a useful effect that can be applied to the deformable display, which is recently attracting attention.

1 is an FT-IR graph of the LPSQ polymer of Preparation Examples 1-3.
2 is a ²⁹ Si-NMR spectrum graph of the LPSQ polymer of Preparation Example 1-3.
Figure 3 is a graph showing the light transmittance in the visible light region band wavelength of Preparation Example 1-3 LPSQ.
4 is a thermogravimetric analysis graph of Preparation Example 1-3 LPSQ, and the illustration of FIG. 4 is a graph showing the thermal transfer behavior of Preparation Example 1-3.
5 is a graph of particle size distribution of amine functionalized Al ₂ O ₃ , measured by dynamic light scattering.
6 is an FT-IR graph of pure Al ₂ O ₃ and amine functionalized Al ₂ O ₃ .
7 is a graph showing the light transmittance in the visible light band region of Examples 1, 3, 4, 5 and Preparation Example 3. FIG.
8 is a TEM image of Examples 1, 3, and 4. FIG.
9 is an FT-IR graph measured before curing, after photocuring, and after photocuring and thermosetting of Preparation Example 3. FIG.
10 is an FT-IR graph measured before curing, after photocuring, and after photocuring and thermosetting of Example 1. FIG.
FIG. 11 is a graph showing the change in the conversion rate of the epoxy, which is the curable unit of Preparation Example 3 and Example 1, after subsequent heat treatment.
12 is a nano indentation graph for analyzing the hardness and the effective elastic modulus of Preparation Example 3, Examples 1-3.
FIG. 13 is an optical microscope image observed under nanoindentation test conditions for observing the modifications of Preparation Example 3, Examples 1-3.
FIG. 14 is H (hardness) and E (elastic modulus) graphs for Preparation Example 3, Examples 1-3 and various engineering materials (epoxy-silica nanocomposites, PEEK, epoxy, soda-lime glass, etc.).

Hereinafter, the present invention will be described in detail.

In one aspect of the invention,

A curable resin composition comprising a ladder polysilsesquioxane, and a mineral filler is provided.

Here, the ladder-type polysilsesquioxane (LPSQ; ladder-type polysilsesquioxanes) may be understood to be a kind of polysilsesquioxane (PSSQ) having a trifunctional silane group, and is a double strand of a ladder-type chemical structure It has a structure made of, having excellent optical transparency and flexibility due to the low rotational barrier of the framework, and can be employed in the curable pendant unit, and can be applied to the present invention without limitation as long as it can have rigidity.

On the other hand, there is a problem with the conventional LPSQ, the conversion rate of the curable residue is low, when applied as a protective layer of the deformable display, there is a problem that the low-temperature curing is not easy, an effort to solve this problem was required.

In the present invention surprisingly further comprising a mineral filler in the curable resin composition, preferably comprising an amine functionalized mineral filler, it was confirmed that the conversion of the curable residues can be significantly increased, from which the curing becomes easier, Through low temperature heat treatment or photocuring, a deformable display protective layer may be manufactured to a desired level.

In one embodiment of the invention,

The ladder-type polysilsesquioxane may be one containing at least one unit of formula (RSiO _1.5 ),

Wherein R may be C ₃ -C ₁₀ cycloalkyl-C ₁ -C ₅ alkyl substituted with at least one epoxy group,

Preferably, R may be C ₅ -C ₆ cycloalkyl-C ₁ -C ₃ alkyl substituted with at least one epoxy group.

In another embodiment of the invention,

The ladder polysilsesquioxane may be one containing at least one unit represented by the following formula (1).

[Formula 1]

(In Formula 1, n is an integer of 1 to 1000).

Alternatively, the ladder-type polysilsesquioxane may include a unit represented by Chemical Formula 1, but may contain 1000 to 100000 based on the number average molecular weight.

In another embodiment of the invention,

The mineral filler is alkaline earth metal oxide

Al ₂ O ₃ , TiO _2, ZrO ₂ , Si0 ₂ , B ₂ O ₃ , P ₂ 0 ₅ , Ge0 ₂ , TeO ₂ , As ₂ O ₃ and V ₂ 0 ₅ , TiO ₂ -coated mica compact (TiO ₂ -coated mica platelets), silicates and borosilicates can be one or more selected from the group consisting of.

In another embodiment of the invention,

The mineral filler may be a core-shell mineral filler, a hollow mineral filler, or a mixture thereof.

Here, the mineral filler is not particularly limited in terms of shape, so long as the advantages of the present invention, that is, the effect of introducing the mineral filler into the LPSQ is achieved, there are various known forms such as core-shell structure, hollow structure It may be a mineral filler, and the present invention includes all of them.

In another embodiment of the invention,

The mineral filler may be an amine functionalized mineral filler, wherein the amine functionalization is not limited if the amine functionalization method commonly used in the art, in particular, a method capable of introducing an amine group to the surface of the filler. Including but not limited to the present invention, for example, amino-propyltrimethoxysilane (APTMS) may be used to introduce an amine group into the mineral filler.

Further, but not limited thereto, amine functionalization using the amino-propyltrimethoxysilane (APTMS) is described in S. Gupta, P. C. Ramamurthy, and G. Madras, Polym. It may be carried out according to the method described in Chem., 2, 221 (2011).

In another embodiment of the invention,

The mineral filler may be preferably contained to such an extent that it is possible to maintain transparent optical properties of the resin composition, and further, in order to improve mechanical properties such as wear resistance after curing of the resin composition, a suitable amount may be selectively contained. have.

Although not limited thereto, preferably the mineral filler may be contained in less than 5% by weight, less than 3% by weight, less than 2% by weight of the resin composition, or preferably less than 1.8% by weight.

Alternatively, the mineral filler may be contained in 0.1 to 2% by weight, 0.2 to 1.9% by weight, or 0.3 to 1.8% by weight of the resin composition.

Alternatively, it can be understood that the mineral filler contains an amount that can effectively participate in the curing reaction, for example, the mineral filler is less than 2% by weight, less than 1% by weight, less than 0.8% by weight of the resin composition It may be contained as, or preferably less than 0.6% by weight.

In another aspect of the invention,

A nanocomposite prepared from the curable resin composition is provided.

Here, the nanocomposite can be understood that the curable resin composition is cured,

The nanocomposite may be prepared by curing the curable resin composition of claim 1 by thermosetting, photocuring, or a combination thereof, for example, photocuring, thermosetting, or thermosetting, followed by photocuring. .

In one embodiment of the invention,

It can be understood that it is hardened by the curable unit which LPSQ of the said curable resin composition has. The curable unit is not particularly limited, but may include an acrylate, an epoxy group, or both, and preferably, an epoxy group.

Here, it can be understood that the conversion of the curable unit is improved from that the nanocomposite further comprises a mineral filler.

Without being limited to a particular theory, it can be understood that the cure group of the curing unit is improved by the amine group introduced from amine functionalizing the mineral filler of the nanocomposite.

In one embodiment of the invention,

The conversion rate of the curing unit of the nanocomposite of the present invention is not particularly limited as long as it is improved compared to pure LPSQ before the mineral filler is introduced into the nanocomposite, but, for example, 70% or more, 80% or more, 90% or more, 91 At least%, at least 92%, at least 93%, at least 95%, or at least 98%.

In another embodiment of the invention,

The photocuring may be cationic photocuring or radical photocuring.

In addition, the curable composition may be performed by further including a photoinitiator, wherein the photoinitiator is not particularly limited as long as it can initiate curing of LPSQ (ladder-type polysilsesquioxane), but is not limited thereto, for example, It may be a sex photoinitiator.

For example, the cationic photoinitiator may be a triaryl-sulfonium hexafluoro-antimonate salt.

In another example, the cationic photoinitiator, diphenyl iodonium hexafluorophosphate, diphenyl iodonium triflate, triphenylsulfonium triflate, diphenyl iodonium nitrate, triarylsulfonium hexafluoro Phosphate salt, 2- (4-methoxystyryl) -4,6-bis (trichloromethyl) -1,3,5-triazine, N-hydroxy-5-norbornene-2,3-dica Voximide perfluoro-1-butanesulfonate, bis (4-tert-butylphenyl) iodonium perfluoro-1-butanesulfonate, bis (4-tert-butylphenyl) iodonium perfluoro- 1-butanesulfonate, bis (4-tert-butylphenyl) iodonium triflate, triphenylsulfonium perfluoro-1-butanesulfonate, tris (4-tert-butylphenyl) sulfonium perfluoro- 1-butanesulfonate, bis (4-tert-butylphenyl) iodonium p-toluenesulfonate, N-hydroxynaphthalimide triflate, diphenyliodonium p-toluenesul Nate, (4-tert-butylphenyl) diphenylsulfonium triflate, tris (4-tert-butylphenyl) sulfonium triflate, (4-phenylthiophenyl) diphenylsulfonium triflate, (4-fluoro Phenyl) diphenylsulfonium triflate, (4-methylthiophenyl) methyl phenyl sulfonium triflate, (4-phenoxyphenyl) diphenylsulfonium triflate, (4-iodophenyl) diphenylsulfonium triflate , Boc-methoxyphenyldiphenylsulfonium triflate, (4-methoxyphenyl) diphenylsulfonium triflate, diphenyliodonium chloride, and the like, but are not limited thereto, and preferably Photoacid generators capable of generating an acid can be used without limitation, and more preferably, a system in which at least one photoacid generator is mixed may be applied comprehensively.

In one embodiment of the present invention, the photoinitiator content is not particularly limited, for example, it may be mixed in 0.1 to 10% by weight based on the total weight of the composition.

On the other hand, if the photocuring causes the conversion of the curable unit of the LPSQ in accordance with the light irradiation, it is possible to use light in the wavelength range not particularly limited, preferably UV irradiation using, for example, a high-pressure mercury lamp It may be initiated by.

By the said light irradiation, the ring-opening reaction of a curable unit, for example, an epoxy group is started, and the said curable resin composition hardens.

In particular, the nanocomposites of the present invention further comprise an amine functionalized mineral filler, so that in addition to conventional photocuring, further heat treatment, for example, when the curable unit is acrylate or epoxy, is at least about 2 hours, It can effectively solve the problem that additional heat treatment was required.

Although not limited thereto, as shown in the following Examples and Experimental Examples of the present invention, it was experimentally shown that the nanocomposite of the present invention achieved a curing conversion at a desired level only by photocuring.

In particular, in shape-deformable displays such as foldable, stretchable, and flexible displays, the use of polymer-based substrates that are vulnerable to mechanical stress is required, and due to the thermal stability of the polymer-based substrates, they must be able to be cured effectively at low temperatures. In the present invention, the curable resin composition and the nanocomposite exhibit excellent curing conversion even by photocuring, and even when the heat treatment optionally includes additional heat treatment, a low temperature short heat treatment, for example, less than 100 ℃, less than 90 ℃, 85 ℃ or less Or only a heat treatment of about 10 to 90 ° C., or 85 ° C. is sufficient, and the heat treatment time is not particularly limited, for example, less than 100 minutes, less than 90 minutes, 80 minutes or less, or 10 to 90 minutes. Alternatively, only 80 minutes of heat treatment can be performed to show sufficient curing conversion.

Therefore, the curable resin composition and the nanocomposite of the present invention can be usefully used in shape-deformable displays such as foldable, stretchable and flexible displays, for example, a protective layer can be applied as a protective film or the like.

Further, in another embodiment of the present invention,

The nanocomposite exhibits excellent mechanical properties, such as excellent hardness and good wear resistance, as shown through the following examples and experimental examples.

The nanocomposites of the present invention can exhibit abrasion resistance, such as glass, and flexibility, such as plastic, from containing an amine functionalized mineral filler in a specific range of concentrations.

Thus, the present invention curable resin composition and nanocomposite, but is not limited to, for example, may be useful as a protective layer, protective film for improving the durability of the display.

Furthermore, in another embodiment of the present invention,

The thermosetting is not particularly limited, and may be not particularly limited as long as it is a predetermined heat treatment and heat treatment time at which the curable resin composition may be cured. Preferably, for example, the substrate applied to the deformable display is polymer-based. In this case, if the low temperature heat treatment can be carried out and the heat treatment time can be made, it may be desirable to shorten it.

In another aspect of the invention,

There is provided a protective film comprising the nanocomposite.

In one embodiment of the invention,

The protective film may be understood as a protective layer, for example, may be used as a display protective film.

Here, the protective film is applied to the protective film, such as electronic devices, displays, such as foldable, stretchable and flexible displays, from mechanical properties such as advantages, excellent stiffness and wear resistance, flexibility of the nanocomposite Can be.

In another aspect of the invention,

A transparent wear-resistant window comprising the curable resin composition or the display protective film, a protective film for protecting electronic devices, a water repellent coating film for building protection, a sunscreen film, a plastic substrate, a flexible water repellent coating film for textile materials, or a weatherproof film for wood (building) protection is provided. .

Hereinafter, the present invention will be described in detail through production examples, examples, and experimental examples. However, the following Preparation Examples, Examples and Experimental Examples should be understood as one example for describing the present invention, and the present invention should not be construed as being limited thereto.

< Preparation Example 1 > Of LPSQ  Manufacture 1

Scheme 1

In a two necked round bottom flask, potassium carbonate (K ₂ CO ₃ ) (0.06 g, 0.44 mmol) and deionized water (7.31 g, 405.5 mmol) were added and stirred for 10 minutes. After complete dissolution of K ₂ CO ₃ , tetrahydrofuran (THF) (13.67 g, 189.5 mmol) was added to the reaction mixture and stirred for an additional 30 minutes. Thereafter, monomer 2- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane (30 g, 121.77 mmol) was added dropwise under argon atmosphere. The reaction solution was stirred for 1 day (LPSQ10) at room temperature. The solvent is then evaporated in vacuo and the residue is dissolved in dichloromethane. After washing several times with deionized water, the organic layer was dried over MgSO ₄ and filtered. Final LPSQ was obtained after evaporation of the solvent and used without further purification.

Preparation Example 2 Preparation of LPSQ 2

LPSQ was prepared in the same manner as in Preparation Example 1, except that the reaction time was 1.5 days (LPSQ15).

Preparation Example 3 Preparation of LPSQ 2

LPSQ was prepared in the same manner as in Preparation Example 1, except that the reaction time was 3 days (LPSQ30).

In Preparation Examples 1-3, all starting materials were purchased from Aldrich and TCI and used without purification.

< Experimental Example  1> Comparison of LPSQ Characteristics According to Polymerization Time

In order to compare the properties of Preparation Example 1-3 LPSQ produced according to polymerization time, molecular weight, 29 Si-NMR, thermal properties, and optical properties were measured and evaluated as follows.

<1-1> molecular weight measurement

The molecular weight and PDI of the LPSQ polymer of Preparation Example 1-3 obtained were determined by gel permeation chromatography (GPC, Waters) using chloroform as eluent and polystyrene as standard at room temperature, and are shown in FIG. 1 and Table 1 below. It was.

As shown in FIG. 1, functional group analysis by FT-IR spectroscopy showed that there are two asymmetric absorption peaks at 1050 and 1150 cm ⁻¹ due to Si—O—Si oscillations in the LPSQ. In addition, there was no characteristic absorption of silanol groups (Si-OH) at 930 and 3500 cm ⁻¹ .

From these results, it was confirmed that the in-situ polymerization proceeded completely through the consumption of the hydrolyzed monomer under the K ₂ CO ₃ catalyst, and that the ladder structure was fairly well formed in all the obtained LPSQs.

<1-2> ²⁹ Si-NMR Spectrum

Meanwhile, ²⁹ Si-NMR spectra were recorded in CDCl ₃ solution at room temperature using AVANCE III (Bruker, 500 MHz), and in T ² (-57 to -61 ppm) and T ³ (-65 to -69 ppm) The intensity of the corresponding characteristic absorption was measured and shown in FIG. 2 and Table 1 below.

The structural orderness of Preparation Example 1-3 LPSQ obtained therefrom was confirmed.

Since the chemical shift of the Si atom depends on the number of its siloxane (—O—SiR 3) bonds, the ²⁹ Si NMR spectrum of Production Example 1-3 LPSQ obtained was recorded and the degree of ladder structure regularity was compared.

Referring to FIG. 2, when the number of siloxane bonds attached to Si atoms through polycondensation is defined as T ⁿ (Si), the structure of T ⁰ (Si) and Si—O—Si (OH) _{2 of} RSi (OH) ₃ are defined. The T1 (Si) structure of R generally shows peaks around -43 and -51 ppm, respectively. However, this peak is longer the polymerization time was completely disappeared, R-Si (OSi-) corresponding to T ³ (-65 to -69 ppm) and _{R-Si (OSi-) 2 (} OH) corresponding to the _three The amount of each T ² (-57 to -61 ppm) structure increased with longer polymerization time.

These results indicate that the hydrolyzed monomer was consumed almost completely during the in situ polymerization, which is consistent with the FT-IR analysis and indicated that a polymer with a more complete ladder structure was formed at longer polymerization times.

<1-3> Thermal Characteristic Evaluation

The thermal stability of Preparation Example 1-3 was analyzed by a TA Q500 instrument by heating to 25 to 600 ℃ under N ₂ atmosphere at a heating rate of 10 ℃ min ^-1, the thermal transition behavior of Preparation Example 1-3 was Discovery DSC TA apparatus Was monitored by DSC at a heating and cooling rate of 10 ° C. min ⁻¹ under N ₂ atmosphere, and the results are shown in FIG. 4 and Table 1 below.

Referring to FIG. 4, during thermogravimetric analysis (TGA), all LPSQs of Preparation Examples 1-3 showed a weight loss of less than 5% up to> 420 ° C. In addition, most of the weight loss occurred at about 150 ° C., which was confirmed to be due to the thermal curing of the epoxy groups in LPSQ (see illustration in FIG. 4).

Furthermore, it can be seen from these results that the thermal stability of Preparative Examples 1-3 LPSQ based curable material will be further enhanced by the preparation of photo- and / or heat-cured films.

<1-3> evaluation of optical properties

Preparation Example 1-3 In order to evaluate the transparency of the LPSQ, the light transmittance was measured for the visible region versus the wavelength, the results are shown in Figure 3 and Table 1.

As shown in FIG. 3, the obtained LPSQ showed excellent optical transparency of at least 99% throughout the visible region.

From this, it can be seen that Preparation Examples 1-3 are useful as matrix resins for polymer-based transparent substrates.

Polymerization time Mn (PDI) T ³ / T ² Transmittance
(at 400 nm) 5% weight loss
Temperature Preparation Example 1 1 day 5,654 (1.95) 6.09 99% 441 ℃ Preparation Example 2 1.5 days 5,121 (1.85) 9.75 99% 429 ℃ Preparation Example 3 3 days 5,808 (1.99) 11.05 99% 432 ℃

As further confirmed in Table 1, the molecular weight of the resulting LPSQ was found to vary greatly with the polymerization time, because the kinetics of the polycondensation mainly depends on the concentration ratio of the base, water and monomers employed in the polymerization.

Example 1 LPSQ-Al ₂ O ₃  Preparation of Nanocomposites 1

Step 1: Al with Amine Group Introduced ₂ O ₃  Preparation of Nanoparticles

S. Gupta, PC Ramamurthy, and G. Madras, Polym. Amine functionalization was performed on Al ₂ O ₃ nanoparticles with amino-propyltrimethoxysilane (APTMS) without catalyst, according to the method described in Chem., 2, 221 (2011).

Specifically, the clean Al ₂ O ₃ nanoparticles were dried in a vacuum oven at 110 ° C. for 15 hours, and the nanoparticles (200 mg) were dispersed in anhydrous toluene through sonication. APTMS (1 ml) was added to the mixture and then refluxed for 20 hours under inert conditions. The resulting powder was collected by centrifugation and washed several times with toluene to remove unreacted APTMS. After drying overnight in a vacuum oven, the resulting powder was redispersed in propylene glycol monomethyl ether acetate (PGMEA, 20% by weight) via sonication.

On the other hand, even when the amine-functionalized Al ₂ O ₃ nanoparticles were dispersed in PGMEA at a concentration of up to 30% by volume after the surface modification, the dispersion properties of the nanoparticles in the organic solvent were dramatically improved and no precipitation was observed.

Step 2: LPSQ-Al ₂ O ₃  Preparation of Nanocomposites

Al ₂ O ₃ nanoparticles introduced with the amine group obtained in step 1 was incorporated into the LPSQ (LPSQ30) of Preparation Example 3 at 0.3% by weight to prepare an LPSQ-Al ₂ O ₃ nanocomposite.

Example 2 LPSQ-Al ₂ O ₃  Preparation of Nanocomposites 2

Except that the Al ₂ O ₃ nanoparticles introduced with the amine group in step 2 of Example 1 was incorporated into LPSQ (LPSQ30) of Preparation Example 3, LPSQ-Al ₂ O ₃ nanocomposites were prepared.

Example 3 LPSQ-Al ₂ O ₃  Preparation of Nanocomposites 3

Except that the Al ₂ O ₃ nanoparticles introduced with the amine group in step 2 of Example 1 was incorporated into the LPSQ (LPSQ30) of Preparation Example 3, LPSQ-Al ₂ O ₃ nanocomposites were prepared.

Example 4 LPSQ-Al ₂ O ₃  Preparation of Nanocomposites 4

Except that the Al ₂ O ₃ nanoparticles in which the amine group was introduced in step 2 of Example 1 was incorporated in the LPSQ (LPSQ30) of Preparation Example 3 in the weight ratio of LPSQ-Al ₂ O ₃ nanocomposites were prepared.

Example 5 LPSQ-Al ₂ O ₃  Preparation of Nanocomposites 5

Except that the Al ₂ O ₃ nanoparticles introduced with the amine group in step 2 of Example 1 was incorporated into the LPSQ (LPSQ30) of Preparation Example 3 in 3.0% by weight, was carried out as in Example 1 LPSQ-Al ₂ O ₃ nanocomposites were prepared.

Experimental Example 2 Al ₂ O ₃  Confirmation of Amine Functionalization of Nanoparticles

In order to confirm the amine functionalization performed in Example step 1 above, FT-IR measurements were performed.

As a result, looking at Figure 6, the amine functionalization of the Al ₂ O ₃ nanoparticles was confirmed as a characteristic peak of the FT-IR spectrum around 1600 and 1120 cm ^-1 corresponding to NH bending and CN elongation, respectively.

In addition, strong absorption peaks around 1120 and 1030 cm −1 indicating Si—O—Al bonds also confirmed successful amine functionalization of Al ₂ O ₃ nanoparticles.

On the other hand, as measured in dynamic light scattering, as confirmed in FIG. 5, D ₅₀ = 51.7 nm of the size distribution of the functionalized Al ₂ O ₃ nanoparticles was found, which was compared with pure Al ₂ O ₃ nanoparticles (50.0 nm). As a result, there was almost no difference in particle size.

Experimental Example 3 Transmission Electron Microscope (TEM) Measurement

Of the Example LPSQ-Al ₂ O ₃ Nanocomposites of the Invention Using High Resolution Transmission Electron Microscopy (HR-TEM), JEM-3010 (JEOL) Nano particle size distribution was measured.

Specifically, after coating the LPSQ30-Al ₂ O ₃ of Example 1-5 or pure LPSQ (Preparation Example 3) on the glass substrate, the resulting film was UV-cured and heat-cured. Subsequently, the cured film was peeled off and separated, and then dispersed in methanol and added dropwise to the TEM grid, and then TEM images were collected.

As a result, as shown in FIG. 7, the transmittance seems to decrease slightly at the wavelength of 400 nm or less due to the scattering effect, but in Example 1-5, it was confirmed that the transmittance of 90% or more was maintained in the visible light region.

On the other hand, as shown in FIG. 8, good compatibility between amine functionalized Al ₂ O ₃ nanoparticles and LPSQ. Compatibility can be confirmed, specifically, the added Al ₂ O ₃ nanoparticles can be present independently up to 3% by weight, some cluster particles were observed from 1.8% by weight.

From TEM image measurements, it was expected that Al ₂ O ₃ nanoparticles could be easily incorporated into the LPSQ polymer matrix via multiple bonds and covalently bonded with the epoxy residues of LPSQ through amine groups introduced to the nanoparticles.

In addition, excellent transparency was thought to be due to nanometer-scale hybridization, as demonstrated by high resolution transmission electron microscopy (TEM) and corresponding energy dispersive X-ray spectroscopy 2D mapping, and their components on the nanometer scale. Was found to be an amorphous material, which was uniformly distributed.

Experimental Example 4 Evaluation of Light- and Heat-Curing Efficiency

Example of the Invention In order to confirm the curing efficiency improved from the amine functionalized Al ₂ O ₃ particles of the nanocomposites, the following experiments were carried out.

Specifically, the light- and heat-curing efficiencies of the LPSQ30-Al ₂ O ₃ (0.3 wt.%) Nanocomposites of Example 1 and pure LPSQ30 were compared. Triaryl-sulfonium hexafluoro-antimonate salt was used as the cationic photoinitiator for the ring-opening reaction of epoxy residues in LPSQ30, the ring-opening reaction being FT around 3400 cm ^-1 corresponding to the hydroxyl group produced by the curing reaction. It was confirmed by the intensity change of the IR spectrum.

As can be seen in FIGS. 9 and 10, irrespective of whether or not LPSQ30 contains Al ₂ O ₃ nanoparticles, the epoxy groups of LPSQ30 are successfully interconnected through ring opening reaction by UV irradiation and subsequent heat treatment. monolithic) material, except for pure LPSQ30, where the remaining epoxy groups are identified after UV curing, essentially requiring additional heat treatment at 85 ° C. for 20 minutes, whereas LPSQ30-Al ₂ O ₃ of the present invention In the case of (0.3% by weight), the curing level of the desired level was confirmed only by UV curing under the same conditions.

Specifically, in order to quantitatively analyze the epoxy conversion, the change in absorption intensity of 880 cm ⁻¹ in the FT-IR spectrum corresponding to the alicyclic epoxy group was monitored several times during ultraviolet exposure and thermal curing at 85 ° C.

As can be seen in FIG. 11, UV exposure effectively promoted the curing reaction to achieve 87% epoxy conversion efficiency at an exposure of 0.5 J in both LPSQ30 and LPSQ30-Al2O3 (0.3 wt%). Epoxy conversion efficiency was found to increase to 89.0% at LPSQ30 and 91.4% (0.3 wt%) at LPSQ30-Al ₂ O ₃ as UV irradiation dose increased to 2 J,

Additionally, when the UV cured sample was continuously heated at 85 ° C. for 20 minutes, the epoxy conversion of LPSQ30 increased to 91.7%, but the conversion of LPSQ30-Al ₂ O ₃ (0.3 wt.%) Remained almost unchanged (91.3%).

Therefore, in the case of LPSQ30-Al ₂ O ₃ (0.3% by weight) of the present invention, even after the subsequent heat treatment, the addition reaction of the epoxy group does not occur, it was confirmed that the subsequent heat treatment is unnecessary, sufficient curing efficiency only by photocuring It was confirmed that this was achieved.

Experimental Example 5 Evaluation of Mechanical Properties

Example of the Invention In order to evaluate the mechanical properties of the LPSQ-Al ₂ O ₃ nanocomposite, the following experiment was carried out.

After forming a uniform film (20 μm) of LPSQ on the glass substrate, specimens for nanoindentation experiments were prepared by a continuous curing process. The sample was irradiated with ultraviolet (2.0 J) using a high pressure mercury lamp and then heat treated at 85 ° C. for 80 minutes. LPSQ-Al ₂ O ₃ nanocomposites uniformly distribute Al ₂ O ₃ nanoparticles (0.3, 0.6 and 0.9 wt.%) To LPSQ30 resin containing cationic photoinitiator (triaryl-sulfonium hexafluoroantimonate salt). After mixing it was made using the same manufacturing process.

Nano indentation (indentation) experiments were performed using a diamond Berkovich (Nano Indenter® XP instrument (MTS system) equipped with Berkovich tip and optical microscope).

All indentation pressure experiments were performed using the same load-unload order. That is, the indentation pressure was given in the order of loading (0-100 mN), holding at 100 mN for 0.5 seconds, and rapidly unloading (100 to 0 mN). Effective elastic modulus and nano indentation hardness were calculated from the rod displacement curve obtained using Oliver-Pharr analysis.

As shown in FIG. 12, in the example of preparing the nanocomposite by mixing the amine functionalized Al ₂ O ₃ nanoparticles with LPSQ, the nano-indentation hardness (H) compared to pure LPSQ was increased from 0.69 to 1.09 GPa and was effective. The modulus of elasticity (E *) increased from 9.21 to 12.16 GPa.

In addition, the nanoindentation test in FIG. 13 did not induce permanent deformation in any specimen, as confirmed by optical microscopy under the specified test conditions.

From these results, it can be seen that the present invention LPSQ30-Al ₂ O ₃ nanocomposites are very suitable for wear-resistant coatings.

On the other hand, in order to compare the promising mechanical properties of the present nanocomposites with those of other general materials, a material selection chart of E versus H of various engineering materials was prepared, as shown in FIG. 14.

In Fig. 14, the diagonal dashed lines represent the selection criteria according to the H ³ / E ^{* 2} values directly related to the resistance to yield pressure. Because of the combined mechanical properties (high H and low E ^* ), the H ³ / E ^{* 2} values of the inventive nanocomposites exceed the highest values of the polymerizable materials and are identified at levels comparable to those of ceramics such as soda-lime glass. It became.

In addition, the present nanocomposites have been found to achieve superior wear resistance compared to epoxy-silica nanocomposites containing similar curable functional groups and reinforcing fillers (silica).

These results were thought to play a pivotal role in the wear resistance of the nanocomposites as the added amine functionalized Al ₂ O ₃ nanoparticles could covalently bind to LPSQ. However, when the content of the added Al ₂ O ₃ nanoparticles exceeds 0.6% by weight, Al ₂ O ₃ is not effectively involved in the curing reaction, it was estimated that there is a decrease in wear resistance due to the plasticizer effect.

According to the present invention, LPSQ nanocomposites containing Al ₂ O ₃ nanoparticles have been found to improve the conversion of epoxy, which is a curing unit applied to LPSQ, compared to pure LPSQ, and also pure LPSQ in mechanical properties such as hardness and wear resistance. It has been found to exhibit improved mechanical properties compared to conventionally used products and materials.

In addition, the excellent mechanical properties of the LPSQ-Al ₂ O ₃ nanocomposites of the present invention are not only three-dimensionally interconnected networks of organic-inorganic hybrid-type chemical structures of LPSQ, but also amine functionalized Al ₂ O covalently interconnected with LPSQ. It can be seen that this is due to the effect (additional reinforcement) provided by the ₃ nanoparticles.

Claims (11)

Ladder-shaped polysilsesquioxanes containing at least one unit of formula (RSiO _1.5 ); And curable resin composition comprising an amine functionalized mineral filler,
Wherein R is C ₃ -C ₁₀ cycloalkyl-C ₁ -C ₅ alkyl substituted with at least one epoxy group.
delete The method of claim 1,
The ladder-type polysilsesquioxane is characterized in that it comprises at least one or more units represented by the following formula (1), curable resin composition:
[Formula 1]

(In Formula 1, n is an integer of 1 to 1000).
The method of claim 1,
The amine functionalized mineral filler is Al ₂ O ₃ , TiO _2, ZrO ₂ , Si0 ₂ , B ₂ O ₃ , P ₂ 0 ₅ , Ge0 ₂ , TeO ₂ , As ₂ O ₃ and V ₂ 0 ₅ , TiO ₂ − At least one member selected from the group consisting of coated mica plates (TiO ₂ -coated mica plates), silicates and borosilicates is amine functionalized.
delete delete Nanocomposite prepared from the curable resin composition of claim 1.
The method of claim 7, wherein
The nanocomposite is prepared by photocuring the curable resin composition, nanocomposites.
The method of claim 8,
When the nanocomposite is photocured, the nanocomposite further comprises a photoinitiator in addition to the curable resin composition.
Display protective film comprising the nanocomposite of claim 7.
A transparent wear-resistant window comprising the curable resin composition of claim 1, a protective film for protecting electronic devices, a water-repellent coating film for building protection, a sunscreen film, a plastic substrate, a flexible water-repellent coating film for textile materials, or a weatherproof film for protecting wood (buildings).

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