Polyester resin composition

Abstract

Provided is a polyester-based resin composition comprising: (a) at least one dicarboxylic acid component selected from aromatic dicarboxylic acids and ester-forming derivatives of the aromatic dicarboxylic acids; (b) a bisphenylfluorene diol component; and (c) a tetracyclobutane diol component, wherein the content of the bisphenylfluorene diol component is 20 to 90 mol % based on the total diol components, and the polyester-based resin composition has a glass transition temperature (Tg) of 100°C or higher.

Description

[Technical field]

[0001] The present invention relates to a polyester resin composition which is a main component of molded articles usable for optical purposes, and relates to a composition which has high heat resistance, a high refractive index and reduced birefringence and is therefore suitable for applications such as optical lenses. [Background technology]

[0002] In order to overcome the problems of glass lenses, such as high specific gravity and low impact resistance, plastic lenses have been introduced, and a representative example is a copolymer of polyethylene glycol-bis-aryl carbonate and modified diaryl phthalate. Although the above material can produce lenses with good physical properties such as moldability, dyeability, hard coat adhesion, and impact resistance, it has a problem of a relatively low refractive index.

[0003] Polymethyl methacrylate and polyolefins having an aliphatic ring are suitable as raw materials for optical lenses because they have high transparency, small birefringence, and little chromatic aberration, but they have a low refractive index and insufficient heat resistance.On the other hand, polycarbonate has excellent transparency and heat resistance, but has the problem of large birefringence.

[0004] In order to solve these problems, it has been proposed to use copolymer polyester resins mainly composed of bisphenylfluorene compounds as diol components as optical materials. However, these materials can only satisfy one of the properties of high heat resistance, high refractive index, or low birefringence in optical products, but do not fully satisfy all physical properties.

[0005] The copolymer polyester resin disclosed in Japanese Patent Registration No. 4908781 has a glass transition temperature (Tg) of 141° C. to 184° C. and a refractive index of 1.655 to 1.663, making it suitable for optical lens applications. However, the birefringence is 85×10 -4 ~140×10 -4 and the birefringence characteristics are not sufficient.

[0006] Therefore, the reality is that there is still a need to develop optical resins that satisfy all of the requirements for heat resistance, refractive index, and birefringence. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 6-184288 [Patent Document 2] JP 2013-49784 A [Patent Document 3] JP 2015-172147 A Summary of the Invention [Problem to be solved by the invention]

[0008] The object of the present invention is to provide a polyester resin having high heat resistance, high refractive index and reduced birefringence by introducing a copolymerization monomer, so as to improve the problems of polyester resins mainly composed of fluorene compounds, which are existing optical materials. [Means for solving the problem]

[0009] In order to achieve the above object, in one embodiment of the present invention, a polyester resin composition is provided having the following composition and conditions.

[0010] (a) at least one dicarboxylic acid component selected from aromatic dicarboxylic acids and ester-forming derivatives of said aromatic dicarboxylic acids; (b) a bisphenylfluorene diol component represented by the following formula I: (c) A polyester resin composition comprising a tetracyclobutane diol component represented by the following chemical formula II, the content of the bisphenylfluorene diol component being 20 to 90 mol % based on the total diol components, and having a glass transition temperature (Tg) of 100° C. or higher:

[0011] [ka] (wherein, in the above formula I, R1 represents a hydrogen atom or a hydroxyalkyl group having 1 to 4 carbon atoms; R2, R3, R4, and R5 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 1 to 4 carbon atoms, or an aralkyl group having 1 to 4 carbon atoms; and R2 to R5 are the same or different from each other);

[0012] [ka] (In the above chemical formula II, at least two of R1 to R8 are each independently a hydroxy group or a hydroxyalkyl group having 1 to 4 carbon atoms, and the remaining are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and the alkyl groups having 1 to 4 carbon atoms are the same or different.)

[0013] In one embodiment, the aromatic dicarboxylic acid may include one or more selected from terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid dimethyl ester, and the ester-forming derivative of the aromatic dicarboxylic acid may include one or more selected from the group consisting of dimethyl terephthalate, dimethyl isophthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl biphenyl-4,4'-dicarboxylate, and 4,4'-diphenyletherdicarboxylic acid dimethyl ester.

[0014] In one embodiment, the tetracyclobutane-based diol component represented by Formula II may be 2,2,4,4-tetramethyl-1,3-cyclobutanediol, and the bisphenylfluorene-based diol component represented by Formula I may be 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene.

[0015] In the embodiment, the content of the tetracyclobutane diol component represented by the formula II may be 10 to 50 mol% based on the total diol components contained in the polyester resin. Furthermore, the tetracyclobutane diol component represented by the formula II may include cis-tetracyclobutane diol and trans-tetracyclobutane diol.

[0016] In one embodiment, the polyester resin composition may further include, in addition to the above-mentioned components, (d) one or more selected from an aliphatic diol component having 2 to 6 carbon atoms or an alicyclic diol component having 6 to 14 carbon atoms. In this case, the aliphatic diol component having 2 to 6 carbon atoms may include one or more selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 1,4-pentanediol, 1,5-pentanediol, 1,3-pentanediol, and neopentyl glycol. In addition, the alicyclic diol component having 6 to 14 carbon atoms may include one or more selected from 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, and 1,4-cyclohexanediethanol. Effect of the Invention

[0017] The polyester resin composition of the present invention has high heat resistance, a high refractive index, and reduced birefringence by introducing a new monomer, which is more suitable for applications such as optical lenses. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Before describing the present invention in detail below, it should be understood that the terms used in the present specification are merely for describing specific embodiments, and are not intended to limit the scope of the present invention, which is limited only by the appended claims. All technical and scientific terms used in the present specification have the same meaning as commonly understood by those of ordinary skill in the art, unless otherwise specified.

[0019] Throughout this specification and the claims, unless otherwise stated, the words comprise, comprise, and comprising are used to mean the inclusion of the mentioned items, steps or group of items and steps and not to the exclusion of any other items, steps or group of items or groups of steps.

[0020] However, the various embodiments and examples of the invention may be combined with other examples unless expressly indicated to the contrary. Any feature indicated as being particularly preferred or advantageous may also be combined with other features and features indicated as being preferred or advantageous.

[0021] The present invention will be described in detail below.

[0022] According to one embodiment of the present invention, there is provided a polyester resin composition comprising: (a) at least one dicarboxylic acid component selected from aromatic dicarboxylic acids and their ester-forming derivatives; (b) a bisphenylfluorene diol component represented by the following chemical formula I; and (c) a tetracyclobutane diol component represented by the following chemical formula II, the content of the bisphenylfluorene diol component being 20 to 90 mol% based on the total diol components, and the glass transition temperature (Tg) being 100°C or higher.

[0023] [ka]

[0024] [ka]

[0025] (In the above chemical formula I, R1 represents a hydrogen atom or a hydroxyalkyl group having 1 to 4 carbon atoms; R2, R3, R4, and R5 may each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 1 to 4 carbon atoms, or an aralkyl group having 1 to 4 carbon atoms; R2 to R5 are the same or different; and in the above chemical formula II, at least two of R1 to R8 are each independently represent a hydroxy group or a hydroxyalkyl group having 1 to 4 carbon atoms, and the remaining are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and the alkyl groups having 1 to 4 carbon atoms are the same or different).

[0026] A polyester resin according to one embodiment of the present invention Fat (a) one or more dicarboxylic acid components selected from aromatic dicarboxylic acids and their ester-forming derivative compounds; (b) a bisphenylfluorene diol component represented by the following chemical formula I; and (c) a bisphenylfluorene diol component represented by the following chemical formula I. II The copolymer can be produced by copolymerizing a tetracyclobutane diol component represented by the following formula:

[0027] [ka]

[0028] (wherein, in formula I, R1 represents a hydrogen atom or a hydroxyalkyl group having 1 to 4 carbon atoms; R2, R3, R4, and R5 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an aryl group having 1 to 4 carbon atoms, or an aralkyl group having 1 to 4 carbon atoms; and R2 to R5 are the same or different from each other);

[0029] [ka]

[0030] (In the above chemical formula II, at least two of R1 to R8 are each independently a hydroxy group or a hydroxyalkyl group having 1 to 4 carbon atoms, and the remaining are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and the alkyl groups having 1 to 4 carbon atoms are the same or different.)

[0031] The dicarboxylic acid component is a basic raw material for polyester resins and can be used without limitation as long as it can produce a polyester resin. The dicarboxylic acid component may be an aromatic dicarboxylic acid or an ester-forming derivative compound of the aromatic dicarboxylic acid.

[0032] The aromatic dicarboxylic acid may include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid. The ester-forming derivatives of the aromatic dicarboxylic acid may include, but are not limited to, dimethyl terephthalate, dimethyl isophthalate, dimethyl 2,6-naphthalenedicarboxylate, dimethyl biphenyl-4,4'-dicarboxylate, 4,4'-diphenyletherdicarboxylic acid dimethyl ester, and the like.

[0033] In polymerizing the polyester resin composition according to an embodiment of the present invention, the aromatic dicarboxylic acid or its ester-forming derivative may be used alone, or two or more selected from the aromatic dicarboxylic acid or its ester-forming derivative may be used together. For example, dimethyl terephthalate and dimethyl isophthalate may be used together, and the molar ratio of dimethyl terephthalate to dimethyl isophthalate may be 20:80 to 80:20.

[0034] As shown in the above examples, when dimethyl terephthalate and dimethyl isophthalate are used together as dicarboxylic acid components in a polyester resin composition, the dicarboxylic acid components have similar structures, which may facilitate the preparation of the resin composition, and the effects of birefringence and heat resistance are different from each other, which may be advantageous for adjusting physical properties. In terms of adjusting such physical properties, the content ratio of dimethyl terephthalate and dimethyl isophthalate can be adjusted, but in the above examples, if the content of dimethyl phthalate is high and the molar ratio of dimethyl terephthalate exceeds 80, the birefringence reduction effect may be reduced. On the other hand, if the content of dimethyl isophthalate is high and the molar ratio exceeds 80, the birefringence reduction effect may be excellent, but it may be disadvantageous in terms of ensuring heat resistance.

[0035] In the polyester resin composition according to an embodiment of the present invention, the bisphenylfluorene diol component represented by the formula I may include, but is not limited to, 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]fluorene, and 9,9-bis[4-(2-hydroxyethoxy)-3,5-diethylphenyl]fluorene.

[0036] The content of the bisphenylfluorene diol component represented by the chemical formula I is preferably 20 to 90 mol% of the total diol components contained in the polyester resin. If the content of the bisphenylfluorene diol component represented by the chemical formula I is less than 20 mol%, the heat resistance and refractive index may decrease, and if it exceeds 90 mol%, the fluidity and mechanical properties of the resin may decrease.

[0037] In one embodiment of the present invention, the tetracyclobutane-based diol component represented by Formula II is a component that helps improve heat resistance, and may include, but is not limited to, 2,2,4,4-tetramethylcyclobutane-1,3-diol (TMCD), 2,2,4,4-tetraethyl-1,3-cyclobutanediol (TECD), and 3,3,4,4-tetramethyl-1,2-cyclobutanediol.

[0038] The content of the tetracyclobutane-based diol component represented by the formula II may be 10 to 80 mol% of the total diol components contained in the polyester resin. If the content is less than 10 mol%, the effect of improving heat resistance may be small, and if it exceeds 80 mol%, the fluidity of the resin may decrease, resulting in decreased moldability and decreased mechanical properties.

[0039] The tetracyclobutane diol component represented by the formula II may contain both cis and trans isomers, and in this case, the molar ratio of cis-tetracyclobutane diol and trans-tetracyclobutane diol may be 1:99 to 99:1. In order to achieve the object of the present invention, it is not necessary to particularly limit the molar ratio of cis and trans isomers of the tetracyclobutane diol component, but the molar ratio of cis-tetracyclobutane diol and trans-tetracyclobutane diol may be 90:10 to 10:90, and further 80:20 to 20:80.

[0040] Experimentally, when tetracyclobutane diol contains both cis and trans isomers, it is believed that the more the cis content is, the better the effect of increasing heat resistance. Although this has not been theoretically established, it is speculated that the reason why heat resistance increases as the cis content is more prevalent is because, in the three-dimensional structure within the molecule, the cis form is advantageous for twisting the molecular chain, and therefore the twisted structure within the molecule increases.

[0041] The polyester resin according to an embodiment of the present invention may further include an aliphatic diol component having 2 to 6 carbon atoms. The aliphatic diol component having 2 to 6 carbon atoms may include, but is not limited to, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 1,4-pentanediol, 1,5-pentanediol, 1,3-pentanediol, neopentyl glycol, and the like.

[0042] The polyester resin according to an embodiment of the present invention may further include an alicyclic diol component having 6 to 14 carbon atoms. The alicyclic diol component having 6 to 14 carbon atoms may include, but is not limited to, 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol, 1,4-cyclohexanediethanol, etc.

[0043] In one embodiment of the present invention, the aliphatic diol component and the alicyclic diol component may be simultaneously contained in the polyester resin. For example, ethylene glycol and 1,4-cyclohexanedimethanol may be used as the aliphatic diol component.

[0044] When the 1,4-cyclohexanedimethanol component is contained, the steric hindrance in the entire molecular structure increases, and the strength of the molecular chain increases, so that the heat resistance and impact strength of the polyester resin can be further improved.

[0045] Furthermore, the 1,4-cyclohexanedimethanol may contain both cis and trans isomers. In this case, the content of the trans isomer in the 1,4-cyclohexanedimethanol may be 70 mol%. The higher the content of the trans isomer in the 1,4-cyclohexanedimethanol, the better the effect of increasing heat resistance, and when the content of the cis isomer is high, the effect of increasing the tensile elongation of the molded article can be obtained.

[0046] In one embodiment of the present invention, the total diol components including the bisphenylfluorene diol component, the tetracyclobutane diol component, or the aliphatic diol component having 2 to 6 carbon atoms may be contained in an amount of 100 parts by mole relative to 100 parts by mole of one or more compounds selected from the aromatic dicarboxylic acid and its ester-forming derivative component.

[0047] By copolymerizing the above-mentioned components, the polyester resin of the present invention has a glass transition temperature (Tg) of 100° C. or more, a refractive index of 1.6 or more, and a 2-fold birefringence of 5.0×10 -4 It can be the following:

[0048] [Example] The present invention will be described in more detail with reference to the following examples. However, these examples are intended to explain the present invention in more detail and are not intended to limit the present invention.

[0049] (Examples 1 to 6 and Comparative Examples 1 to 5) The dicarboxylic acid component and the diol component were added to a polyester production polymerization reactor equipped with an agitator to produce a copolymer polyester resin. The types and contents of the dicarboxylic acid and diol components are shown in Table 1 below.

[0050] The polymerization reaction proceeded in two stages. In the first stage, the raw materials and catalyst were all put into the reactor, and the temperature of the reaction tube was raised from normal pressure to 190°C over one hour. The temperature of the reaction tube was then raised to 220°C over two hours, and then to 240°C over an additional hour while methanol was discharged from within the tube.

[0051] For the second-stage polymerization, after the outflow of methanol was completed, the tube temperature was gradually raised to 280°C in a vacuum atmosphere over the course of 1 hour, and then a condensation polymerization reaction was carried out at 280°C for approximately 4 hours. After the reaction was completed, stirring was stopped, nitrogen was introduced to release the vacuum, and the copolymer polyester resin was granulated while applying pressure.

[0052] [Table 1]

[0053] The compositions of the polyester resins obtained in Examples 1 to 6 and Comparative Examples 1 to 5 are shown in Table 2 below.

[0054] [Table 2]

[0055] The polyester resins obtained in Examples 1 to 6 and Comparative Examples 1 to 5 To fat The physical properties of the polymer were measured, including intrinsic viscosity, glass transition temperature (Tg), refractive index, and two-fold birefringence. The measured physical properties are shown in Table 3, and the measurement methods for each property are as follows.

[0056] [Measurement of intrinsic viscosity] 2g of sample was placed in 25ml of ortho-chlorophenol and dissolved at 100℃ and 200rpm for 1 hour. 7.5ml of sample solution was taken using a whole pipette in a thermostatic bath at 25℃, then placed in a Canon viscometer and incubated for 20 minutes. The solution taken into the viscometer was sucked up using a vacuum and passed the upper scale of the meniscus viscometer, and at the same time a second timer was started. The number of seconds it took for the meniscus to pass the lower scale was measured to calculate the intrinsic viscosity.

[0057] [Measurement of glass transition temperature] The glass transition temperature of the test specimen was measured using a differential scanning calorimeter (DSC1) manufactured by Mettler Toledo Co., Ltd., based on the standard of ASTM D3418.

[0058] [Refractive index measurement] 1 g of resin was hot-pressed at 200°C to produce a transparent film with a thickness of approximately 150 μm, and the refractive index was measured at 20°C using an Abbe refractometer (ATAGO DR-M4). The refractive index values ​​shown in the examples and comparative examples were measured at a wavelength of 589 nm.

[0059] [Measurement of double birefringence] 1g of resin was hot-pressed at 200℃ to produce a film with a thickness of about 100-400um, which was then cut into a 15×40mm piece. It was then stretched twice at 20% / sec at Tg+10℃, and then quenched to obtain a stretched film. The birefringence of the obtained stretched film when stretched twice was measured using Oji's KOBRA-WPR.

[0060] [Table 3]

[0061] From the measured physical properties, the polyester resin compositions prepared in Examples 1 to 6 have a glass transition temperature of 100° C. or higher, good heat resistance, a high refractive index of 1.6 or higher, and a 2-fold birefringence of 5.0×10 -4 It can be seen that the value is low, as shown below.

[0062] On the other hand, in the case of Comparative Example 1, in which the bisphenylfluorene diol component was out of the appropriate content range, the refractive index was not measurable, and in the case of Comparative Example 2, in which no tetracyclobutane diol component was included, the 2-fold birefringence was high and unsuitable for optical use. In addition, in the case of Comparative Example 3, in which only an aliphatic diol component was included in the diol component, the glass transition temperature was lower than 100°C, the heat resistance was insufficient, and the 2-fold birefringence properties were also inappropriate. In the case of Comparative Example 4, in which no bisphenylfluorene diol component was included, the 2-fold birefringence properties were satisfied, but the heat resistance was insufficient.

[0063] On the other hand, in the case of Comparative Example 5 in which the bisphenylfluorene diol component and the tetracyclobutane diol component were out of the appropriate range, the refractive index was low and the composition was not suitable for optical use. [Industrial Applicability]

[0064] The polyester resin composition according to the present invention has high heat resistance, a high refractive index, and can reduce birefringence, and can therefore be used to provide molded articles suitable for applications such as optical lenses.

Claims

1. (a) at least one dicarboxylic acid component selected from aromatic dicarboxylic acids and ester-forming derivatives of the aromatic dicarboxylic acids; (b) a bisphenylfluorene diol component represented by the following formula I: (c) containing a tetracyclobutane-based diol component represented by the following chemical formula II: The dicarboxylic acid component comprises terephthalic acid or dimethyl terephthalate and isophthalic acid or dimethyl isophthalate in a molar ratio of 80:20 to 20:80; The content of the bisphenylfluorene diol component is 20 to 90 mol % based on the total diol components, The content of the tetracyclobutane diol component is 10 to 50 mol % based on the total diol components, The glass transition temperature (Tg) of the polyester resin produced by copolymerization is 100° C. or higher. Polyester resin composition: 【Chemistry 1】 (In the above formula I, R １ represents a hydrogen atom or a hydroxyalkyl group having 1 to 4 carbon atoms; R ２ , R ３ , R ４ , R ５ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ２ ~R ５ are the same or different), 【Chemistry 2】 (In the above formula II, R １ ~R ８ Two of the above are each independently a hydroxy group or a hydroxyalkyl group having 1 to 4 carbon atoms, and the remaining are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and the alkyl groups having 1 to 4 carbon atoms are the same or different.

2. 2. The polyester resin composition according to claim 1, wherein the aromatic dicarboxylic acid further comprises at least one selected from the group consisting of 2,6-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid dimethyl ester.

3. The aromatic dicarboxylic acid further includes at least one selected from 2,6-naphthalenedicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, and 4,4'-diphenyletherdicarboxylic acid dimethyl ester; The polyester resin composition according to claim 1, wherein the ester-forming derivative of the aromatic dicarboxylic acid further comprises at least one selected from the group consisting of dimethyl 2,6-naphthalenedicarboxylate, dimethylbiphenyl-4,4'-dicarboxylate, and 4,4'-diphenyletherdicarboxylic acid dimethyl ester.

4. 2. The polyester resin composition according to claim 1, wherein the tetracyclobutane diol component represented by the chemical formula II is 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

5. 2. The polyester resin composition according to claim 1, wherein the bisphenylfluorene diol component represented by formula I is 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene.

6. 2. The polyester resin composition according to claim 1, wherein the tetracyclobutane diol component represented by the chemical formula II includes cis-tetra-cyclobutane diol and trans-tetra-cyclobutane diol.

7. 2. The polyester resin composition according to claim 1, further comprising (d) at least one selected from the group consisting of an aliphatic diol component having 2 to 6 carbon atoms and an alicyclic diol component having 6 to 14 carbon atoms.

8. The polyester resin composition according to claim 7, wherein the aliphatic diol component having 2 to 6 carbon atoms includes at least one selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 1,4-pentanediol, 1,5-pentanediol, 1,3-pentanediol, and neopentyl glycol.

9. The polyester resin composition according to claim 7, wherein the alicyclic diol component having 6 to 14 carbon atoms includes at least one selected from the group consisting of 1,2-cyclohexanediol, 1,3-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanediethanol, 1,3-cyclohexanediethanol and 1,4-cyclohexanediethanol.

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