KR102556372B1 - Polyester-based polymer and optical material comprising the same - Google Patents

Abstract

The present invention relates to a polyester-based resin and an optical member including the same, and more particularly, to a polyester-based resin including an aromatic repeating unit having a specific structure and an optical member including the same.

Description

Polyester-based resin and an optical member containing the same {POLYESTER-BASED POLYMER AND OPTICAL MATERIAL COMPRISING THE SAME}

It relates to a polyester-based resin and an optical member including the same, and more specifically, to a polyester-based resin including an aromatic repeating unit having a specific structure and an optical member including the same.

Recently, light and flexible plastic-based optical devices such as substrate materials for display devices, light extraction materials and optical adhesives for OLED devices, antireflection coatings, micro lenses for CCDs, and metal oxide semiconductors (CMOS) have been used in various fields. In order to be applied, plastic optical members satisfying various physical properties are being developed.

In particular, it is necessary to develop an optical member capable of realizing high refraction according to the demand for miniaturization and light weight of optical devices. In the case of a glass material conventionally used as a high refractive index material, there was a problem in that it was difficult to apply to various products due to its low stability and high specific gravity. Accordingly, the development of a high refractive index material based on a transparent soft polymer is required.

Examples of polymer materials usable as optical members include polyethylene glycol bisallyl carbonate, polymethyl methacrylate (PMMA), and a mixture of modified diaryl phthalate and ethylene glycol bisallyl carbonate. However, since these plastic materials have a low refractive index of about 1.5 seconds, there is a disadvantage in that the thickness of the product must be thick to increase the refractive angle.

Since an optical lens made of a mixture of diaryl phthalate and ethylene glycol bisallyl carbonate has a low refractive index, the edge thickness of the lens becomes thick, and distortion due to birefringence and chromatic aberration occurs.

Examples of transparent resins for optics having a high refractive index include polycarbonate made of bisphenol A (nD = 1.586, υD = 29) and polystyrene (nD = 1.578, υD = 34). In particular, polycarbonate resins made of bisphenol A have been widely studied as optical members because they have a high refractive index and excellent heat resistance and excellent mechanical properties. However, since both polycarbonate resins and polystyrene made of bisphenol A have a weakness of high birefringence, their applications are limited.

Therefore, while implementing a high refractive index, it is required to develop a polymer material capable of minimizing birefringence and distortion due to a high Abbe number and realizing appropriate levels of mechanical properties.

An object of the present invention is to provide a polyester-based resin capable of exhibiting high refractive index and high transmittance and at the same time implementing excellent mechanical properties, and an optical member including the same.

According to the present invention, a polyester-based resin comprising a repeating unit represented by Formula 1 is provided:

[Formula 1]

In Formula 1,

A is a substituted or unsubstituted biphenylene,

R ₁ and R ₂ are each independently hydrogen or substituted or unsubstituted C _1-10 alkyl;

m1 and m2 are each independently an integer of 0 to 4.

Further, according to the present invention, an optical member comprising the polyester-based resin having the specific structure described above is provided. The optical member according to the present invention can implement a high refractive index of about 1.65 to 1.80, so it is easy to apply to miniaturized optical devices.

Unless explicitly stated herein, terminology is only intended to refer to specific embodiments and is not intended to limit the present invention.

As used herein, the singular forms also include the plural forms unless the phrases clearly dictate the contrary.

As used herein, the meaning of 'comprising' specifies a particular property, domain, integer, step, operation, element, and/or component, and other particular property, domain, integer, step, operation, element, component, and/or group. does not exclude the presence or addition of

And, in this specification, terms including ordinal numbers, such as 'first' and 'second', are used for the purpose of distinguishing one component from other components, and are not limited by the ordinal number. For example, within the scope of the present invention, a first component may also be referred to as a second component, and similarly, a second component may be referred to as a first component.

Since the present invention can have various changes and various forms, specific embodiments will be exemplified and described in detail below. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

I. Polyester-based resin

The present inventors, by polymerizing a diol component containing an ethylene glycol group on both sides of biphenylfluorene and a diacyl compound containing a biphenylene structure, realize superrefractive index by conjugated pi bonds of aromatic structures, and titrate within the molecule. Problems such as the occurrence of birefringence due to the packing structure and the deterioration of workability have been improved. In particular, it was confirmed that the compound having the above structure has excellent mechanical properties and can be used for various optical members.

According to one embodiment of the present invention, the polyester-based resin includes a repeating unit represented by Formula 1 below:

[Formula 1]

In Formula 1,

A is a substituted or unsubstituted biphenylene,

R ₁ and R ₂ are each independently hydrogen or substituted or unsubstituted C _1-10 alkyl;

m1 and m2 are each independently an integer of 0 to 4.

In the present invention, PART 1 is a structure in which a structure derived from a diol compound is introduced at both ends of the core structure of biphenylfluorene, and excessive packing in the molecule is suppressed by the fluorene core structure, resulting in a high value of about 1.65 or more While realizing the refractive index, it was possible to improve the problems of birefringence and deterioration of workability at the same time.

In addition, PART 2 is a structure derived from a diacyl-based compound containing an acyl group at the end of the biphenylene core structure of A, for example, in the group consisting of diacyl halides, dicarboxylic acids and dicarboxylates. A structure derived from one or more selected compounds. In the present invention, the biphenylene structure (-A-) realizes the above-described high refractive properties while improving mechanical properties, so that it can be applied to various light-term members.

According to one embodiment of the present invention, in Formula 1, R ₁ and R ₂ may each independently be hydrogen, methyl, or ethyl, preferably hydrogen. In addition, n1 and n2 may each independently be an integer of 1 to 3, and m1 and m2 may each independently be 0 or 1.

In the present invention, the biphenylene of A may be one in which all linking groups are bonded at para positions, and in this case, it is suitable for improving mechanical properties.

According to one embodiment of the present invention, the repeating unit represented by Chemical Formula 1 may be represented by Chemical Formula 1-1:

[Formula 1-1]

.

.

In the present invention, the polyester-based resin may have a glass transition temperature (Tg) of about 180 °C to about 190 °C, preferably about 185 °C to about 190 °C, due to the above-described structural characteristics. Accordingly, remarkably improved optical properties can be implemented without deterioration of thermal stability and mechanical properties of the polyester-based resin.

In the present invention, 'pyrolysis initiation temperature (Td _1% or Td _5% )' means the temperature at which about 1% by weight or about 5% by weight of the total weight of the resin is decomposed. Specifically, in thermogravimetric analysis (TGA), the temperature at which the degree of thermal decomposition of the total resin reaches about 1% by weight or about 5% by weight is measured, and in the present invention, a value that is an index of thermal stability. can be seen as

In the present invention, the polyester-based resin may have a thermal decomposition initiation temperature (Td _1% ) of 390°C or higher, preferably 395°C or higher, or 400°C or higher due to the structural characteristics described above. In addition, the thermal decomposition initiation temperature (Td _5% ) may be 410°C or higher, preferably 415°C or higher, or 418°C or higher.

In the present invention, when the thermal decomposition initiation temperature (Td _1% ) is less than 390 ° C or the thermal decomposition initiation temperature (Td5%) is less than 410 ° C, the resin has low heat resistance and is applied as a product and durability is significantly reduced when placed in a high temperature environment and yellowing may occur.

In the present invention, the polyester-based resin may have a weight average molecular weight (measured by GPC) of 20,000 g/mol to 200,000 g/mol, preferably 40,000 g/mol to 150,000 g/mol. When it exceeds 200,000 g/mol, fluidity is lowered and processability is lowered during actual product manufacturing, and when it is lower than 20,000 g/mol, mechanical properties are lowered and durability of the product is lowered.

According to one embodiment of the present invention, the polyester-based resin may be mixed with additional additives within a range that does not affect the desired effect of the present invention. For example, antioxidants, release agents, ultraviolet absorbers, fluidity modifiers, crystal nuclear agents, reinforcing agents, dyes, antistatic agents, antibacterial agents, and the like.

In the present invention, the polyester-based resin may be synthesized by condensation polymerization of a diol-based compound represented by Chemical Formula 1-A and a diacyl-based compound represented by Chemical Formula 1-B.

[Formula 1-A]

[Formula 1-B]

In the formula, A, R ₁ , R ₂ , m1 and m2 are as defined above.

The reaction may be prepared by a known melt polycondensation method in which a synthesis method known in the art is applied without particular limitation, and the reaction is performed in the presence of a basic compound catalyst, a transesterification catalyst, or a mixed catalyst composed of these.

Examples of the basic compound catalyst include alkali metal compounds, alkaline earth metal compounds, and nitrogen-containing compounds, and catalyst compounds known in the art may be used without particular limitation. Salts of zinc, tin, zirconium, and lead are preferably used as the transesterification catalyst, and these may be used alone or in combination, and catalyst compounds known in the art may be used without particular limitation.

As the reaction solvent, diphenyl ether, N-methyl pyrrolidine (NMP), dimethylacetamide (DMAc), and the like may be used, preferably diphenyl ether, and the like.

The reaction may be carried out as a single reaction or a multi-step reaction, and may be carried out at a temperature of 180 °C to 260 °C, preferably 200 °C to 240 °C.

II. optical member

According to another embodiment of the present invention, an optical member including a polyester-based resin including a repeating unit represented by Chemical Formula 1 is provided.

[Formula 1]

In Formula 1,

A is a substituted or unsubstituted biphenylene,

R ₁ and R ₂ are each independently hydrogen or substituted or unsubstituted C _1-10 alkyl;

m1 and m2 are each independently an integer of 0 to 4.

In the present invention, all of the above information about the polyester-based resin including the repeating unit represented by Chemical Formula 1 may be equally applied.

According to one embodiment of the present invention, the optical member may have a refractive index of about 1.65 or more measured according to the ASTM D542 standard due to the structural characteristics of the polyester-based resin including the repeating unit of Formula 1 described above, preferably. , may be from about 1.65 to about 1.80. When exhibiting the above high refractive index, it can be used in a miniaturized optical member to implement excellent light efficiency.

In addition, according to one embodiment of the present invention, the optical member has a transmittance of about 80% or more, preferably about 80% to 90%, or about 85 % to 80%. In the case of exhibiting the above high transmittance, it can be used in various optical members to realize excellent light efficiency.

The optical member according to the present invention is a material applied to various fields requiring super refractive index, and includes, for example, an optical lens, a coating layer of an optical lens, a display substrate, and the like.

Meanwhile, according to another aspect of the present invention, a display device including the above-described optical member may be provided.

The optical member according to one aspect of the present invention, while having a high refractive index of about 1.65 or more and high transmittance, is lightweight, has excellent strength and hardness, and can be used in various types of display devices as described above.

The polyester-based resin according to the present invention makes it possible to provide an optical member capable of implementing excellent mechanical properties while implementing a high refractive index and high transmittance.

Hereinafter, preferred embodiments are presented to aid understanding of the invention. However, the following examples are only for exemplifying the invention and are not intended to limit the invention only to these.

[ manufacturing example ] - Polyester resin synthesis

manufacturing example 1 - Synthesis of A-1 resin

In a 250 mL three-necked round bottomed flask, 4.39 g of 9,9-Bis[4-(2-hydroxyethoxy)phenyl]fluorene, 2.79 g of 4,4'-Biphenyldicarbonyl Chloride, solvent diphenyl ether 35.9 g was added to proceed with the reaction at 220 ° C. for 4 hours. An excess of MeOH was added to the reaction-completed solution to obtain a precipitate, which was filtered to obtain crystals. Thereafter, this was dried in an oven at a temperature of 100°C to obtain a polyester-based resin (A-1). At this time, the prepared polyester resin had a weight average molecular weight of 97,000 g/mol, a glass transition temperature of 187°C, Td _1% of 400°C, and Td _5% of 418°C.

* The weight average molecular weight was measured by GPC using PS Standard (Standard) using an Agilent 1200 series.

* Glass transition temperature (Tg) was measured according to the ISO 11359-2 method.

* Thermal decomposition initiation temperature (Td _1% ) and thermal decomposition initiation temperature (Td _5% ) were obtained by heating the prepared resin to 800 ° C at a rate of 10 ° C / min using an instrument thermogravimetric analyzer (TGA Q500). A thermogravimetric analysis (TGA) was performed, and the temperature at which the degree of thermal decomposition of the entire resin reached about 1% by weight or about 5% by weight was measured.

[ Example and comparative example ] - Specimen preparation

Example One

The polycarbonate resin A-1 obtained in Preparation Example was dissolved in dimethylacetamide (DMAc) to prepare a casting solution of about 15 wt%. casting through, and a film specimen was prepared by performing a drying process at about 200° C. so that the final thickness was about 10.7 μm. The glass substrate was removed after the drying process.

comparative example One

Film specimens were prepared in the same manner as in Example 1, except that about 3 wt% of a casting solution was prepared by dissolving a resin (B-1, Mw 120,000) having a repeating unit structure of Formula b-1 below in THF. .

[Formula b-1]

.

.

Experimental example

The properties of the specimens made of the resins of Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1 below.

Experimental example 1: Refractive index evaluation

The refractive index (n) and Abbe's number (vD) were measured according to the measurement method of ASTM D542 using a ATAGO refractometer, and the resulting values are shown in Table 1 below.

The Abbe number (vD) is a value calculated according to Equation 1 below by measuring refractive indices of nD (589.16nm), nF (486.26m), and nC (656.36nm) in the corresponding wavelength region, respectively.

[Equation 1]

vD = (nD-1)/(nF-nC)

Experimental example 2: Permeability evaluation

The transmittance at 400 nm was measured according to the measurement method according to the ISO 13468 standard using UV-3600 (SHIMADZU), and the results are shown in Table 1.

division profit Refractive index (n) Abbe number (υD) Permeability (%)
at 400nm type Tg(℃) Td _1% Td _5% Example 1 A-1 187 400 418 1.65 20.35 86 Comparative Example 1 B-1 160 - 407 1.64 19.21 78

As can be seen from Table 1, when the polyester-based resin having a specific structure according to the present invention is used, transmittance is excellent, and in particular, a high refractive index of 1.65 and a high Abbe number can be simultaneously realized, making it easy to use as a miniaturized optical member. confirmed one.

In the case of Comparative Example 1 using a resin having a different core structure of the repeating unit from that of the present invention, it was confirmed that the thermal properties of the resin itself were lowered, and the refractive index, Abbe number, and transmittance characteristics were significantly lowered compared to the examples.

Claims (8)

A polyester-based resin comprising a repeating unit represented by Formula 1 below and having a glass transition temperature (Tg) of 180° C. to 190° C.:
[Formula 1]

In Formula 1,
A is biphenylene;
R ₁ and R ₂ are each independently hydrogen, methyl or ethyl;
m1 and m2 are each independently 0 or 1.
delete According to claim 1,
A polyester-based resin having a thermal decomposition onset temperature (Td _1% ) of 390°C or higher.
According to claim 1,
A polyester-based resin having a thermal decomposition onset temperature (Td _5% ) of 410°C or higher.
According to claim 1,
A polyester-based resin having a weight average molecular weight (measured by GPC) of 20,000 g/mol to 200,000 g/mol.
An optical member comprising a repeating unit represented by Formula 1 below and a polyester-based resin having a glass transition temperature (Tg) of 180° C. to 190° C.:
[Formula 1]

In Formula 1,
A is biphenylene;
R ₁ and R ₂ are each independently hydrogen, methyl or ethyl;
m1 and m2 are each independently 0 or 1.
According to claim 6,
An optical member having a refractive index of 1.65 or more measured according to the ASTM D542 standard.
According to claim 6,
An optical member having a transmittance of 80% or more in a wavelength region of 300 nm to 700 nm measured according to ISO 13468 standards.