KR20200078154A - Novel copolymer and optical article comprising the same - Google Patents

Abstract

A copolymer according to the present invention has improved moisture stability while maintaining thermal stability compared to poly(methyl methacrylate) known in the prior art, and thus can be used as a material for various optical articles.

Description

Novel copolymer and optical article comprising the same}

The present invention is to provide a copolymer having a novel structure with improved thermal stability while maintaining thermal stability compared to polymethyl methacrylate and an optical article comprising the same.

Polymethyl methacrylate (PMMA) is widely used in various optical materials due to its high transparency. However, polymethyl methacrylate has a disadvantage in that it has a glass transition temperature of about 100 to 110°C, which is vulnerable to heat.

Techniques for modifying the structure of polymethyl methacrylate have been reported to compensate for the disadvantages of heat and moisture. Representatively, a method of introducing a bulky substituent into polymethylmethacrylate has been reported, and it is known that vulnerability to heat can be improved by introducing a bulky substituent. However, while the stability to heat increases, the absorbency is rather weak, and thus cannot be a fundamental solution.

As another method, development of a resin having improved stability against heat and moisture using coordination polymerization such as cyclic olefin copolymer (COC) or cyclic olefin polymer (COP) has been reported, but the fragility of COC and multi-step synthesis of COP There is a problem in that manufacturing is complicated by the like.

Accordingly, the present inventors tried to improve the vulnerability to moisture while maintaining the thermal stability of the polymethyl methacrylate. As a result, by introducing a bulky substituent and a perfluorinated substituent as described below, The invention was completed by confirming that is achieved.

The present invention is to provide a copolymer having a novel structure with improved stability to moisture while maintaining thermal stability compared to polymethyl methacrylate.

In addition, the present invention is to provide an optical article comprising the copolymer.

In order to solve the above problems, the present invention provides a copolymer represented by the following Chemical Formula 1 or 2.

[Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,

R ₁ is C _1-5 alkyl, C _3-10 cycloalkyl, dicyclopentanyl, adamatanyl, or isobornyl,

R _'1 is C _1-5 alkyl, C _3-10 cycloalkyl, cycloalkyl-di fentanyl (dicyclopentanyl), Ada manta carbonyl (adamatanyl), or isobornyl (isobornyl) and, with the proviso that, R ₁ and R' ₁ are different from each other and,

R ₂ is perfluoro (C _6-10 aryl), pentafluorobenzyl, or perfluoro (C _1-10 alkyl),

n, n'and m are each independently an integer of 50 to 1000.

Hereinafter, the present invention will be described in detail.

(Copolymer)

The copolymer according to the present invention includes substantially two types of repeating units as shown in Chemical Formula 1, or additionally repeating units as shown in Chemical Formula 2 in addition thereto. Here, the formulas 1 and 2 mean that two or three types of repeat units are randomly coupled, and should be understood as a random copolymer. In addition, the copolymer according to the present invention does not contain substantially other repeating units other than the two or three repeating units.

Based on the formula (1), the copolymer according to the present invention basically includes the first repeating unit, and according to this structure, the copolymer according to the present invention may have thermal stability. In addition, the copolymer according to the present invention includes a second repeating unit in addition to the first repeating unit, and the second repeating unit is for introducing a perfluorinated substituent. Thermal stability is increased by the first repeating unit, but when only the first repeating unit is included, stability to moisture is not improved. Thus, by including the second repeating unit together, thermal stability and moisture stability are also increased.

Preferably, R ₁ is methyl, or cyclohexyl. Preferably, R ₂ is perfluorophenyl, or pentafluorobenzyl.

In Chemical Formula 1, n and m mean the number of repetitions of each repeating unit, which can be adjusted by adjusting the starting material used in the method for preparing a copolymer according to the present invention, as will be described in the manufacturing method to be described later. have.

Preferably, the ratio of n and m is 1:3 to 3:1.

Further, the copolymer represented by Chemical Formula 2 includes an additional repeating unit in the copolymer represented by Chemical Formula 1 described above, and is specifically for introducing a R′ ₁ substituent. R _'1 is not the same as the substituent to be included as an additional repeating unit, R ₁ substituent. Copolymers according to the present invention as R _'1 substituent is further introduced into the structure is to have a more bulky, and can be further improved thermal stability.

Preferably, R _'1 is a cycloalkyl-di fentanyl (dicyclopentanyl). The dicyclopentanyl as used in the present invention is a structure derived from dicyclopentanyl methacrylate, and specifically means the following chemical structure.

In the formula (2), n, n'and m mean the number of repetitions of each repeating unit, as described in the production method to be described later, by controlling the starting material used in the production method of the copolymer according to the present invention , Can be adjusted. Preferably, the ratio of n and m is 1:3 to 3:1, and n:n' is 1:3 to 3:1.

Preferably, the weight average molecular weight of the copolymer is 10,000 to 1,000,000, and more preferably 100,000 to 300,000. Preferably, the copolymer has a PDI (molecular weight distribution; Mw/Mn) of 1 to 4.

In addition, the copolymer according to the present invention improves thermal stability by including two or three types of repeating units as described above, and the result of the improved thermal stability can be described as a high decomposition temperature and a glass transition temperature.

Preferably, the decomposition temperature of the copolymer according to the invention is 150 to 250°C. Preferably, the glass transition temperature of the copolymer according to the present invention is 80 to 130°C, more preferably 100 to 130°C.

In addition, the copolymer according to the present invention improves the stability to moisture by including two or three types of repeating units as described above, and the result of the improved stability to moisture can be described as having low water absorption. The absorption rate can be measured according to ASTM D570 as in the experimental example to be described later. Specifically, the copolymer can be molded in the form of a film to measure the absorption rate, wherein the thickness of the film is 0.28 mm to 0.31 mm.

Preferably, the absorption rate of the copolymer according to the present invention is 0.5% or less, more preferably 0.4% or less, 0.3% or less, or 0.2% or less. On the other hand, the lower limit of the absorption rate is theoretically 0%, but is, for example, 0.001% or more, 0.01% or more, or 0.1% or more.

(Method for producing copolymer)

Among the copolymers according to the present invention, the copolymer represented by Chemical Formula 1 may be prepared by copolymerizing a compound represented by Chemical Formula 1-1 and a compound represented by Chemical Formula 1-2.

[Formula 1-1]

[Formula 1-2]

In Chemical Formulas 1-1 and 1-2, R ₁ and R ₂ are as defined above.

In addition, among the copolymers according to the present invention, the copolymer represented by Chemical Formula 2 includes the compound represented by Chemical Formula 1-1, the compound represented by Chemical Formula 1-2, and the compound represented by Chemical Formula 1-3 below. It can be produced by copolymerization.

[Formula 1-3]

In Formula 1-3, R _'1 is as defined above.

The copolymerization can be used without limitation, a method for producing polymethyl methacrylate, except that the above-described compound is used as a starting material. In one example, the copolymerization may be performed by using the above-mentioned compound as a starting material, and in the presence of a polymerization initiator (eg, AIBN), copolymerize in a nitrogen atmosphere. The copolymerization may be performed at 40°C to 90°C for 1 hour to 48 hours. In addition, it may further include the step of purifying the prepared copolymer.

(Optical goods)

The copolymer according to the present invention described above has improved thermal stability while maintaining thermal stability compared to polymethyl methacrylate, which is widely used as an optical material, and has excellent transparency, and thus can be widely used as an optical material. have.

Accordingly, various optical articles, for example, transparent substrates and lenses, can be used as materials for various articles.

As in Examples and Comparative Examples to be described later, the above-described copolymer according to the present invention includes two or three types of copolymers, and thus it can be confirmed that the stability against heat and moisture is excellent, and thus, the conventionally used polymethyl meta. It can be seen that acrylate can be substituted.

As described above, the copolymer according to the present invention is characterized in that it can be used as a material for various optical articles, while improving thermal stability while maintaining thermal stability, as compared to conventionally known polymethyl methacrylate.

Hereinafter, preferred embodiments are provided to help understanding of the present invention. However, the following examples are only provided to more easily understand the present invention, and the contents of the present invention are not limited thereby.

Example 1: P(MMA-co- PFBMA )( poly (methyl methacrylate -co- pentafluorobenzyl methacrylate))

To a flask containing anhydrous toluene (5 g), MMA (methyl methacrylate, 0.7 g, 7.00 mmol) and PFBMA (pentafluorobenzyl methacrylate, 4.3 g, 16.2 mmol) were added, and AIBN (azobisisobutyronitrile, 7.5 mg, 0.045 mmol) was added. After sealing, the reaction was carried out overnight at 80°C under nitrogen. To this, THF was added and the diluted solution was added dropwise to methanol to purify the polymer. This purification process was repeated 3 times to remove unreacted monomers and solvents. The purified polymer was dried in a vacuum oven at 60° C. and molecular weight was confirmed through GPC. At this time, GPC was analyzed at 40° C. with THF as eluent, and PS (polystyrene) was used as a standard sample at a flow rate of 1 ml/min. (4.2 g, Mn=56,000 g/mol, Mw=115,000 g/mol, PDI=2.05).

Example 2: P( CHMA -co- PFBMA )( poly ( cyclohexyl methacrylate -co-pentafluorobenzyl methacrylate))

To a flask containing anhydrous toluene (5 g) was added CHMA (cyclohexyl methacrylate, 3 g, 17.8 mmol), PFBMA (2 g, 7.5 mmol) and AIBN (7.5 mg, 0.045 mmol), sealed and sealed at 80° C. under nitrogen. The reaction proceeded overnight. To this, THF was added and the diluted solution was added dropwise to methanol to purify the polymer. This purification process was repeated 3 times to remove unreacted monomers and solvents. The purified polymer was dried in a vacuum oven at 60° C. and molecular weight was confirmed through GPC. At this time, GPC was analyzed at 40° C. with THF as eluent, and PS (polystyrene) was used as a standard sample at a flow rate of 1 ml/min. (4.3 g, Mn=85,000 g/mol, Mw=253,000 g/mol, PDI=2.97).

Example 3: P(MMA-co- DCPMA -co- PFBMA )( poly (methyl methacrylate Preparation of -co-dicyclopentanyl-co-pentafluorobenzyl methacrylate)

To a flask containing anhydrous toluene (5 g), add MMA (0.775 g, 7.74 mmol), DCPMA (dicyclopentanyl methacrylate, 2.25 g, 10.2 mmol), PFBMA (1.98 g, 7.42 mmol), AIBN (7.5 mg, 0.045 mmol) ) Was further added and sealed to proceed the reaction at 80° C. under nitrogen overnight. To this, THF was added and the diluted solution was added dropwise to methanol to purify the polymer. This purification process was repeated 3 times to remove unreacted monomers and solvents. The purified polymer was dried in a vacuum oven at 60° C. and molecular weight was confirmed through GPC. At this time, GPC was analyzed at 40° C. with THF as eluent, and PS (polystyrene) was used as a standard sample at a flow rate of 1 ml/min. (4.3 g, Mn=72,000 g/mol, Mw=192,000 g/mol, PDI=2.67).

Comparative example 1: PMMA( poly (methyl methacrylate )) Preparation of homopolymer

After adding MMA (5 g, 49.9 mmol) and AIBN (7.5 mg, 0.045 mmol) to the flask containing anhydrous toluene (5 g), the mixture was sealed and reacted at 80° C. under nitrogen overnight. After adding THF, the diluted solution was added dropwise to methanol to purify the polymer. This purification process was repeated 3 times to remove unreacted monomers and solvents. The purified polymer was dried in a vacuum oven at 60° C. and molecular weight was confirmed through GPC. At this time, GPC was analyzed at 40° C. with THF as eluent, and PS (polystyrene) was used as a standard sample at a flow rate of 1 ml/min. (4.2 g, Mn = 96,000 g/mol, Mw = 198,000 g/mol, PDI = 2.06).

Experimental Example

The following physical properties were evaluated for the polymers of the prepared examples and comparative examples.

(1) Decomposition temperature (Td)

Using a TGA2 model from Mettler Toledo, one set point was identified by measuring a range of 30 to 600°C at a scan rate of 10°C/min. The sample was measured by drying in a vacuum oven at 60° C. before measurement.

(2) Glass transition temperature (Tg)

DSC was measured by using 2 cycles of Mettler Toledo's DSC3+ model at a scan rate of 30°C to 250°C at a scan rate of 10°C/min, and the mid-point of the peak found in the second was confirmed by Tg. The sample was measured by drying in a vacuum oven at 60° C. before measurement.

(3) Absorption rate

Water absorption was measured according to ASTM D570. Specifically, after drop casting a polymer solution dissolved in toluene at 30 wt% in a 2×2 cm dish, the film was obtained by drying sequentially at 40° C. for 1 hour, 80° C. for 1 hour, and 110° C. for 24 hours. . The thickness of the dried sample was measured using a top-probe meter. After measuring the weight (W ₀ ) of the obtained film and soaking it in distilled water for 2 weeks, the weight (W ₁ ) of the film was measured and the absorption rate was calculated by the following equation.

Absorption rate (%) = (W ₁ -W ₀ )/W ₀ × 100

(4) Refractive index and Abbe's number

A polymer solution diluted to 10 wt% was added to a Si wafer, and the refractive index (n _D ) was measured using an ellipsometer by coating using a spin casting method. The Abbe number (v _D ) was calculated using the following formula.

v _D = (n _D -1)/(n _F -n _C )

The results are shown in Table 1 below.

Thermal properties Absorption rate Optical properties Td
(℃) Tg
(℃) Film thickness
(mm) Absorption rate
(%) Refractive index Abbe Example 1 P(MMA-co-PFBMA) 190 87 0.286 0.17 1.485 42.5 Example 2 P(CHMA-co-PFBMA) 226 108 0.292 0.29 1.492 50.0 Example 3 P(MMA-co-DCPMA-co-PFBMA) 225 123 0.310 0.41 1.500 52.3 Comparative Example 1 PMMA 269 125 0.133 0.95 1.491 56.9

As shown in Table 1 above, it was confirmed that the polymer according to the present invention had a similar thermal characteristic and a low absorption rate compared to the comparative example of polymethyl methacrylate. In particular, the film thickness of the copolymer of the Example was confirmed to be significantly lower in water absorption, despite being thicker than the film thickness of the Comparative Example.

Claims (10)

Copolymer represented by Formula 1 or 2 below:
[Formula 1]

[Formula 2]

In Chemical Formulas 1 and 2,
R ₁ is C _1-5 alkyl, C _3-10 cycloalkyl, dicyclopentanyl, adamatanyl, or isobornyl,
R _'1 is C _1-5 alkyl, C _3-10 cycloalkyl, cycloalkyl-di fentanyl (dicyclopentanyl), Ada manta carbonyl (adamatanyl), or isobornyl (isobornyl) and, with the proviso that, R ₁ and R' ₁ are different from each other and,
R ₂ is perfluoro (C _6-10 aryl), pentafluorobenzyl, or perfluoro (C _1-10 alkyl),
n, n'and m are each independently an integer of 50 to 1000.
According to claim 1,
R ₁ is methyl or cyclohexyl,
Copolymer.
According to claim 1,
The R _'1 is di cycloalkyl fentanyl (dicyclopentanyl),
Copolymer.
According to claim 1,
R ₂ is perfluorophenyl, or pentafluorobenzyl,
Copolymer.
According to claim 1,
n:m is 1:3 to 3:1,
Copolymer.
According to claim 1,
n:n' is 1:3 to 3:1,
Copolymer.
According to claim 1,
The copolymer has a weight average molecular weight of 10,000 to 1,000,000,
Copolymer.
According to claim 1,
PDI of the copolymer is 1 to 4,
Copolymer.
According to claim 1,
The glass transition temperature of the copolymer is 80 to 130 ℃,
Copolymer.
According to claim 1,
The copolymer has an absorption rate of 0.5% or less measured according to ASTM D570,
Copolymer.